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1.  An innovative method to evaluate the suture compliance in sealing the surgical wound lips 
Background and aim: The increasing number of surgical procedures performed with local anesthesia, followed by immediate patient discharge from the hospital, emphasizes the need for a tight waterproof suture that is capable of maintaining its tensile strength in the postoperative phase when the wound tumescence, edema due to the anesthetic drug, and surgical trauma disappear. Moreover, the issue of having an accurate surgical wound closure is very relevant in vivo in order to prevent hemorrhage and exogenous microbial infections. This study aimed at designing a new a lab technique that could be used for evaluating the best surgical material. Using such a technique, we compared the wound-lip-sealing properties of three commonly-used suture threads, namely polyurethane, polypropylene, and polyamide.
Materials and methods: The mechanical properties of same-size suture threads made from polyurethane, polypropylene, and polyamide, were compared in order to define the one that possess the best elastic properties by being able to counteract the tension-relaxation process in the first 12 hours following surgery. The tension holding capacity of the suture materials was measured in both in vivo and in vitro experiments. The surface area of the scar associated with the three different suture threads was measured and compared, and the permeability of the three different suture threads was assessed at 0 minute, 2 minute, 4 minute, 6 minute, and 8 minute- interval.
Results: Results showed that polyurethane suture threads had significantly (P < 0.05) better tensile strength, elongation endurance before breakage, and better elasticity coefficient as compared to polypropylene and polyamide suture threads. Moreover, polyurethane suture threads were significantly (P < 0.05) more impermeable as compared to the other two suture thread types (polypropylene and polyamide). This impermeability was also associated with a tighter wound-lip-sealing ability, and with significantly (P < 0.05) less scar formation.
Conclusion: Among the main concerns that surgeons, physicians, and patients often have is the development infection, oozing, and scar at the incision site following suturing. This always raises the question about which suture to use to avoid the above problems. This study provides evidence that the new technique developed in our lab could be used to compare the wound-lip sealing properties of different surgical suture threads. Using such a technique, the results show that polyurethane is significantly better than other commonly-used suture threads, like polypropylene and polyamide, in relation to wound sealing and scar formation.
PMCID: PMC2583338  PMID: 19015745
suture threads; polyurethane; polypropylene; polyamide; wound-lip-sealing properties
2.  Craniofacial Sutures: Morphology, Growth, and In Vivo Masticatory Strains 
Journal of morphology  1999;242(2):167.
The growth and morphology of craniofacial sutures are thought to reflect their functional environment. However, little is known about in vivo sutural mechanics. The present study investigates the strains experienced by the internasal, nasofrontal, and anterior interfrontal sutures during masticatory activity in 4–6-month-old miniature swine (Sus scrofa). Measurements of the bony/fibrous arrangements and growth rates of these sutures were then examined in the context of their mechanical environment. Large tensile strains were measured in the interfrontal suture (1,036 με ± 400 SD), whereas the posterior internasal suture was under moderate compression (−440 με ± 238) and the nasofrontal suture experienced large compression (−1,583 με ± 506). Sutural interdigitation was associated with compressive strain. The collagen fibers of the internasal and interfrontal sutures were clearly arranged to resist compression and tension, respectively, whereas those of the nasofrontal suture could not be readily characterized as either compression or tension resisting. The average linear rate of growth over a 1-week period at the nasofrontal suture (133.8 μm, ± 50.9 S.D) was significantly greater than that of both the internasal and interfrontal sutures (39.2 μm ± 11.4 and 65.5 μm ± 14.0, respectively). Histological observations suggest that the nasofrontal suture contains chondroid tissue, which may explain the unexpected combination of high compressive loading and rapid growth in this suture.
doi:10.1002/(SICI)1097-4687(199911)242:2<167::AID-JMOR8>3.0.CO;2-1
PMCID: PMC2813870  PMID: 10521876
sutures; mastication; bone strain; skull; growth; miniature swine
3.  AN EXPERIMENTAL INVESTIGATION OF THE TREATMENT OF WOUNDS OF THE HEART BY MEANS OF SUTURE OF THE HEART MUSCLE 
It would, of course, be incorrect to attempt to draw conclusions as to the dangers and the chances of success of suture of cardiac wounds in man from the results obtained by animal experimentation. Animals are placed in very unfavorable conditions after the operation. They are very restless and cannot be kept quiet. Ideal cleanliness is impossible and the animals may infect their wound by rubbing the external wound against the dirt on the floor of their cage. From the animal mortality in these investigations no rigid inferences applicable to human beings can therefore be made. Some conclusions of importance can, however, be drawn. Above all, my experiments seem to show that the mammalian heart will bear a much greater amount of manipulation than has hitherto been suspected. Very large wounds of the heart can heal and the healing process occurs in a manner entirely analogous to that in other muscular tissues. Even an extensive suture of the heart-wall of rabbits and dogs, although we know that thereby a large number of muscle fibres are destroyed and replaced by connective tissue, does not interfere with the function of the cardiac muscle as a whole. Can some of the results in the above recorded experiments be, with some restrictions of course, applied to the human heart? I think that this question must be answered in the affirmative. If we compare the knowledge we possess of wounds of the heart in man, with that obtained from animal experiments, and find that they agree in all essential particulars, then we are justified in reasoning by analogy that suture of wounds of the heart in man will give results similar to those obtained in the animal. In the last few decades, the advances made in all the branches of medicine—especially in pathology, bacteriology and surgery—have been due to a great extent to the generalization of the results of animal experimentation. To the careful and critical investigator, the results obtained in the animal experiment have always been of the greatest value in indicating to him the possibility of results to be obtained by similar procedures in the human body. From the study of wounds of the heart in man, and from the results obtained in my experiments, this conclusion seems therefore justified: wounds of the heart in man, when all other means have been tried and found wanting, can and ought to be closed by suture. The application itself of the suture is devoid of the one great danger that was feared in the past, i. e. of sudden arrest of the heart during the manipulations incident upon the application of the sutures. The number of sutures should be as small as possible so as to limit the amount of connective tissue which will be formed; for all the muscle fibres that are compressed by the sutures eventually atrophy and are replaced by new-formed connective tissue. It is probable that this connective tissue will not lead to degenerative changes in the heart-muscle. On the post-mortem table, fibrous plaques are often found in the otherwise normal human heart. In a number of the muscles of the body fibrous bands—tendinous intersections as they are called—are normally found. In the large number of microscopic sections of the heart-muscle that I have examined, I could find no evidence of pathological changes in the muscle fibres some distance from the scar. For similar reasons the suture should always be an interrupted one. We have shown that there are dangers and disadvantages in the continuous suture both on theoretical grounds and in practical use. The sutures should be passed through as little of the heart substance as possible; if they penetrate the epicardium and a small part of the thickness of the heart-muscle it will generally be sufficient. When the heart's action is not too rapid, each suture should be tied during a diastolic relaxation of the part under treatment. On this point we have not yet any experience in man. Cappelen, in his patient, tied the sutures during systole. Rehn tied them in his case during diastole. Only time and further experience will show how much importance is to be attached to this point. All that can be said, in the present state of our knowledge, is, that on theoretical grounds and from animal experimentation, it must be considered safest to tie the sutures during diastole. On first sight, it might appear difficult to apply sutures to an organ in such constant motion as is the heart. In practice, however, the difficulties have been proven not to be so great as might appear. The heart may be grasped with a forceps and the needle and suture easily passed. It is no more difficult to pass and tie a suture in a large dog than in a small rabbit. Hence we should infer that the difficulties of this procedure in the human heart, are not so great, a fact that has been borne out by the experience of those surgeons who have reported cases of heart-suture in man. The cases will always be few in which this extreme method of treatment—for so we must style it—is necessary. Indeed, of the patients that come under the care of the surgeon, there are some who will recover from even large heart wounds without any local treatment at all. Cases have been recently reported by Conner, Brugnoli, Hamilton and others, where after wounds as large as three centimetres, the hæmorrhage ceased spontaneously and the patients recovered. One cannot say, therefore, that wounds larger than a certain size must always be sutured. Each case must be carefully considered by itself. When we examine the nine cases of suture of the human heart in man (see pages 487 to 490) we cannot but hope for considerable success from this new method of surgical procedure. Of the nine cases, four recovered entirely, and four died of complications referable to other organs—quite an encouraging record in a few cases. Finally, I may be permitted to summarize these conclusions as follows: 1. Suture of a wound of the heart as a final resort is an operation worthy of consideration in some cases and often justifiable. 2. Suture of wounds of the heart in animals, and also in man, is devoid of the danger of sudden arrest of the heart, due to the manipulation of the heart incident to the procedure, unless Kronecker's coördination centre be injured. 3. The suture should be an interrupted one of silk, applied in most cases so that the epicardium and superficial layers of the myocardium should be the only ones penetrated, and tied, when possible, during diastole. 4. No stated indications can be given as to the cases that are operable or the time when the operation should be done. Each case must be considered by itself for symptoms which would justify operative interference.
PMCID: PMC2118011  PMID: 19866920
4.  New suture materials for midline laparotomy closure: an experimental study 
BMC Surgery  2014;14:70.
Background
Midline laparotomy closure carries a significant risk of incisional hernia. This study examines the behavior of two new suture materials, an elastic material, polyurethane (PUe), and a barbed polydioxanone (PDXb) suture thread in a rabbit model of midline incision closure.
Methods
Three 2-cm midline incisions were made in 68 New Zealand White rabbits. The incisions were closed by running suture using four 3/0 threads: polypropylene (PP) (Surgipro®, Covidien), PUe (Assuplus®, Assut Europe), PDX (Assufil®, Assut Europe) or PDXb (Filbloc®, Assut Europe). Animals in each suture group were euthanized 3 weeks and 6 months after surgery. Histological sections of the tissue-embedded sutures were subjected to morphological, collagen expression, macrophage response and uniaxial tensiometry studies.
Results
No signs of wound dehiscence or complications were observed. At 3 weeks, all sutures were surrounded by connective tissue composed mainly of collagen III. PUe showed greater collagen I expression than the other sutures. All sutures elicited a macrophage response that diminished from 3 weeks to 6 months (p < 0.001). This response was similar for the non-reabsorbable sutures (PP and PUe) yet PDXb showed a significantly greater response than the other reabsorbable suture (PDX) at 3 weeks (p < 0.01). At this early time point, the tensile strength of PUe was similar to that of control intact tissue (p > 0.05).
Conclusion
Three weeks after surgery, PUe revealed more collagen I deposition than the remaining materials and this translated to a similar biomechanical behavior to linea alba, that could avoid the appearance of short term dehiscences and thus reduce the incidence of incisional hernia. PDXb provides no additional advantages in their behavior regarding PDX suture.
doi:10.1186/1471-2482-14-70
PMCID: PMC4174389  PMID: 25231161
Polypropylene; Polyurethane; Polydioxanone; Abdominal wall closure; Midline closure; Laparotomy closure; Barbed sutures; Elastic sutures
5.  A Laparoscopic Knot-Tying Device for Minimally Invasive Cardiac Surgery 
Objectives
Intracorporeal suturing and knot tying can complicate, prolong or preclude minimally invasive surgical procedures, reducing their advantages over conventional approaches. An automated knot-tying device has been developed to speed suture fixation during minimally invasive cardiac surgery while retaining the desirable characteristics of conventional hand-tied surgeon's knots: holding strength and visual and haptic feedback. A rotating slotted disk (at the instrument's distal end) automates overhand throws, thereby eliminating the need to manually pass one suture end through a loop in the opposing end. Electronic actuation of this disk produces left or right overhand knots as desired by the operator.
Methods
To evaluate the effectiveness of this technology, 7 surgeons with varying laparoscopic experience tied knots within a simulated minimally invasive setting, using both the automated knot-tying tool and conventional laparoscopic tools. Suture types were 2-0 braided and 4-0 monofilament.
Results
Mean knot-tying times were 246 ±116 seconds and 102 ±46 seconds for conventional and automated methods, respectively, showing an average 56% reduction in time per surgeon (p=0.003, paired t-test). The peak holding strength of each knot (the force required to break the suture or loosen the knot) was measured using tensile testing equipment. These peak holding strengths were normalized by the ultimate tensile strength of each suture type (57.5 N and 22.1 N for 2-0 braided and 4-0 monofilament, respectively). Mean normalized holding strengths for all knots were 68.2% and 71.8% of ultimate tensile strength for conventional and automated methods, respectively (p= 0.914, paired t-test).
Conclusions
Experimental data reveal that the automated suturing device has great potential for advancing minimally invasive surgery: it significantly reduced knot-tying times while providing equivalent or greater holding strength than conventionally tied knots.
doi:10.1016/j.ejcts.2009.09.024
PMCID: PMC2826593  PMID: 19854658
automated suturing; knot-tying; fixation; minimally invasive surgery
6.  Development of a Surgically Optimized Graft Insertion Suture Technique to Accommodate a Tissue-Engineered Tendon In Vivo 
BioResearch Open Access  2013;2(5):327-335.
Abstract
The traumatic rupture of tendons is a common clinical problem. Tendon repair is surgically challenging because the tendon often retracts, resulting in a gap between the torn end and its bony insertion. Tendon grafts are currently used to fill this deficit but are associated with potential complications relating to donor site morbidity and graft necrosis. We have developed a highly reproducible, rapid process technique to manufacture compressed cell-seeded type I collagen constructs to replace tendon grafts. However, the material properties of the engineered constructs are currently unsuitable to withstand complete load bearing in vivo. A modified suture technique has been developed to withstand physiological loading and off load the artificial construct while integration occurs. Lapine tendons were used ex vivo to test the strength of different suture techniques with different sizes of Prolene sutures and tissue-engineered collagen constructs in situ. The data were compared to standard modified Kessler suture using a standard tendon graft. Mechanical testing was carried out and a finite element analysis stress distribution model constructed using COMSOL 3.5 software. The break point for modified suture technique with a tissue-engineered scaffold was significantly higher (50.62 N) compared to a standard modified Kessler suture (12.49 N, p<0.05). Distributing suture tension further proximally and distally from the tendon ends increased the mechanical strength of the repairs. We now have ex vivo proof of concept that this suture technique is suitable for testing in vivo, and this will be the next stage of our research.
doi:10.1089/biores.2013.0028
PMCID: PMC3776617  PMID: 24083088
biomaterials; extracellular matrix; tissue engineering; wounds
7.  Load transmission in the nasofrontal suture of the pig, Sus scrofa 
Journal of biomechanics  2006;40(4):837-844.
The nasofrontal suture links the nasal complex with the braincase and is subject to compressive strain during mastication and (theoretically) tensile strain during growth of nasal soft tissues. The suture’s ability to transmit compressive and tensile loads therefore affects both cranioskeletal stress distribution and growth. This study investigated the in vitro viscoelastic and failure properties of the nasofrontal suture in the pig, Sus scrofa. Suture specimens from two ages were tested in compression and tension and at fast and slow rates. In additional specimens, strain gauges were applied to the suture and nasal bone for strain measurement during testing. Relaxation testing demonstrated higher elastic moduli in tension than compression, regardless of test rate or pig age. In contrast, maximum elastic moduli from failure tests, as well as peak stresses, were significantly higher in compression than in tension. Sutures from older pigs tended to have higher elastic moduli and peak stresses, significantly so for tensile relaxation moduli. Strain gauge results showed that deformation at the suture was much greater than that of the nasal bone. These data demonstrate the viscoelasticity and deformability of the nasofrontal sutural ligament. The suture achieved maximal resistance to tensile deformation at low loads, corresponding with the low tensile loads likely to occur during growth of nasal soft tissues. In contrast, the maximal stiffness in compression at high loads indicates that the suture functions with a substantial safety factor during mastication.
doi:10.1016/j.jbiomech.2006.03.011
PMCID: PMC2789259  PMID: 16690062
Mechanical testing; Compression; Tension; Facial suture
8.  Healing of the Goat Anterior Cruciate Ligament After a New Suture Repair Technique and Bioscaffold Treatment 
Tissue Engineering. Part A  2013;19(19-20):2292-2299.
Primary suture repair of the anterior cruciate ligament (ACL) has been used clinically in an attempt to heal the ruptured ACL. The results, however, were not satisfactory, which in retrospect can be attributed to the used suturing technique and the suboptimal healing conditions. These constraining conditions can be improved by introducing a new suturing technique and by using small intestinal submucosa (SIS) as a bioscaffold. It is hypothesized that the suturing technique keep the torn ends together and that SIS enhance and promote the healing of the ACL. The goat was used as the study model. In the Suture group, the left ACL was transected and suture repaired with a new locking suture repair technique (n=5) allowing approximation and fixation under tension. The Suture-SIS group underwent the same procedure with the addition of SIS (n=5). The right ACL served as control. After 12 weeks of healing, anterior–posterior translation and in situ force of the healing ACL were measured, followed by the measurement of the cross-sectional area and structural stiffness. Routine histology was performed on tissue samples. Gross morphology showed that the healing ACL was continuous with collagenous tissue in both groups. The cross-sectional area of the Suture and the Suture-SIS group was 35% and 50% of the intact control, respectively. The anterior–posterior translations at different flexion angles were statistically not different between the Suture group and the Suture-SIS group. Only the in situ force at 30° in the Suture-SIS group was higher than in the Suture group. Tensile tests showed that the stiffness for the Suture group was not different from the Suture-SIS group (31.1±8.1 N/mm vs. 41.9±18.0 N/mm [p>0.05]). Histology showed longitudinally aligned collagen fibers from origo to insertion. More fibroblasts were present in the healing tissue than in the control intact tissue. The study demonstrated the proof of concept of ACL repair in a goat model with a new suture technique and SIS. The mechanical outcome is not worse than previously reported for ACL reconstruction. In conclusion, the approach of using a new suture technique, with or without a bioscaffold to heal the ACL is promising.
doi:10.1089/ten.tea.2012.0535
PMCID: PMC3761389  PMID: 23725556
9.  Visual Measurement of Suture Strain for Robotic Surgery 
Minimally invasive surgical procedures offer advantages of smaller incisions, decreased hospital length of stay, and rapid postoperative recovery to the patient. Surgical robots improve access and visualization intraoperatively and have expanded the indications for minimally invasive procedures. A limitation of the DaVinci surgical robot is a lack of sensory feedback to the operative surgeon. Experienced robotic surgeons use visual interpretation of tissue and suture deformation as a surrogate for tactile feedback. A difficulty encountered during robotic surgery is maintaining adequate suture tension while tying knots or following a running anastomotic suture. Displaying suture strain in real time has potential to decrease the learning curve and improve the performance and safety of robotic surgical procedures. Conventional strain measurement methods involve installation of complex sensors on the robotic instruments. This paper presents a noninvasive video processing-based method to determine strain in surgical sutures. The method accurately calculates strain in suture by processing video from the existing surgical camera, making implementation uncomplicated. The video analysis method was developed and validated using video of suture strain standards on a servohydraulic testing system. The video-based suture strain algorithm is shown capable of measuring suture strains of 0.2% with subpixel resolution and proven reliability under various conditions.
doi:10.1155/2011/879086
PMCID: PMC3049425  PMID: 21436874
10.  Effect of suture technique on the occurrence of incisional hernia after elective midline abdominal wall closure: study protocol for a randomized controlled trial 
Trials  2015;16:52.
Background
Based on a recent meta-analysis, a continuous suture technique with a suture to wound length ratio of at least 4:1, using a slowly absorbable monofilament suture material, is recommended for primary median laparotomy closure. Incisional hernia, which develops in 9 to 20% of patients, remains the major complication of abdominal wall closure. Current clinical data indicate that the incidence of incisional hernias increases by 60% between the first and the third year after median laparotomy, implicating that a follow-up period of 1 year postoperatively is too short with regard to this common complication. Trauma to the abdominal wall can be reduced by improvements in suture technique as well as suture material. Several factors, such as stitch length, suture tension, elasticity, and tensile strength of the suture material are discussed and currently under investigation. A Swedish randomized controlled trial showed a significant reduction in the incisional hernia rate by shortening the stitch length. However, a non-elastic thread was used and follow-up ended after 12 months. Therefore, we designed a multicenter, international, double-blinded, randomized trial to analyze the influence of stitch length, using an elastic, extra-long term absorbable monofilament suture, on the long term clinical outcome of abdominal wall closure.
Methods
In total, 468 patients undergoing an elective, median laparotomy will be randomly allocated to either the short stitch or the long stitch suture technique for abdominal wall closure in a 1:1 ratio. Centers located in Germany and Austria will participate. The primary endpoint measure is the incisional hernia rate 1 year postoperatively, as verified by ultrasound. The frequency of short term and long term complications as well as costs, length of hospital stay and patients’ quality of life (EQ-5D-5 L) will be considered as secondary parameters. Following hospital discharge, patients will be examined after 30 days and 1, 3, and 5 years after surgery.
Discussion
This study will provide further evidence on whether a short stitch suture technique in combination with an elastic, extra-long term absorbable monofilament suture can prevent incisional hernias in the long term, compared with the long stitch suture technique.
Trial registration
NCT01965249.
doi:10.1186/s13063-015-0572-x
PMCID: PMC4336759
Abdominal wall closure; Incisional hernia; Laparotomy; Large bites; Small bites; Suture technique
11.  Force Sensing in Surgical Sutures 
PLoS ONE  2013;8(12):e84466.
The tension in a suture is an important factor in the process of wound healing. If there is too much tension in the suture, the blood flow is restricted and necrosis can occur. If the tension is too low, the incision opens up and cannot heal properly. The purpose of this paper is to describe the design and evaluation of the Stitch Force (SF) sensor and the Hook-In Force (HIF) sensor. These sensors were developed to measure the force on a tensioned suture inside a closed incision and to measure the pulling force used to close the incision. The accuracy of both sensors is high enough to determine the relation between the force in the thread of a stitch and the pulling force applied on the suture by the physician. In a pilot study, a continuous suture of 7 stitches was applied on the fascia of the abdominal wall of multiple pigs to study this relationship. The results show that the max force in the thread of the second stitch drops from 3 (SD 1.2) to 1 (SD 0.3) newton after the 4th stitch was placed. During placement of the 5th, 6th and 7th stitch, the force in the 2nd stitch was not influenced anymore. This study indicates that in a continuous suture the force in the thread remains constant up to more than 3 stiches away from the pulled loose end of the suture. When a force feedback tool is developed specially for suturing in surgery on patients, the proposed sensors can be used to determine safety threshold for different types of tissue and sutures.
doi:10.1371/journal.pone.0084466
PMCID: PMC3871579  PMID: 24376812
12.  Novel method of knotless vesicourethral anastomosis during robot-assisted radical prostatectomy: feasibility study and early outcomes in 30 patients using the interlocked barbed unidirectional V-LOC180 suture 
Purpose:
Our purpose was to describe the safety and feasibility of a running posterior reconstruction (PR) integrated with continuous vesicourethral anastomosis (VUA) using a novel self-cinching unidirectional barbed suture in robot-assisted radical prostatectomy (RARP).
Methods:
Between March and October 2010, 30 consecutive patients with organ-confined prostate cancer underwent RARP by an experienced single surgeon (KCZ). Upon completion of radical prostatectomy, urinary reconstruction was carried out using 2 knotless, interlocked 6-inches 3-0 V-Loc-180 suture. The left tail of the suture was initially used for PR (starting at 5-o’clock and ran to re-approximate the retrotrigonal layer to the rectourethralis) followed by left-sided VUA (from 6- to 12-o’clock), while the right-sided suture completed the right-sided VUA. Assurance of watertight closure with an intraoperative 300 cc saline visual cystogram was performed in all cases prior to case completion. Perioperative outcomes and 30-day complications were recorded.
Results:
All anastamoses were performed without assistance and without knot tying. Median time for nurse setup and urinary reconstruction was 40 seconds (interquartile range [IQR] 25–60) and 14.6 min (IQR 10–18), respectively. The need to readjust suture tension or place Lapra-Ty clips (Ethicon Endo-Surgery, Cincinnati, OH) to establish watertight closure was observed in 2 cases (7%). No patient had clinical urinary leak and there was no urinary retention after catheter removal on mean postoperative day 5 (IQR 4–6).
Conclusions:
Our clinical experience with a novel technique using the interlocked V-Loc suture during RARP for both PR and anastomosis appears to be safe and efficient. Using the barbed suture prevents slippage and eliminates the need for bedside assistance to maintain suture tension or knot tying, thus assuring watertight tissue closure.
doi:10.5489/cuaj.10194
PMCID: PMC3114030  PMID: 21672482
13.  Useful ‘sliding-lock-knot’ technique for suturing dural patch to prevent cerebrospinal fluid leakage after extended transsphenoidal surgery 
Background:
Postoperative cerebrospinal fluid (CSF) leakage is a major problematic complication after extended transsphenoidal surgery (TSS). Watertight closure of the sellar dura with a fascial patch graft is a method of choice for preventing CSF leakage; however, suturing and knotting in a deep and narrow operative field is technically challenging and time consuming. To present a simple and effective knotting technique named the ‘sliding-lock-knot’ technique, in which the knot can easily be slid to the suturing point and tied automatically using only a single string, without loosening.
Methods:
We use a 6-0 nylon suture and Mosquito forceps. At first, after putting a stitch, a single knot is made by hand out of the nasal cavity. Then the ‘sliding-lock-knot’ is made using a forceps as shown in the illustration. The knot slides deep into the operative field through the nostril and it is automatically tied only by pulling a string.
Results:
A 73-year-old woman presented with progressive visual deterioration. She had an intra-and suprasellar craniopharyngioma that was compressing the optic chiasm. She underwent an extended TSS, and the tumor was totally resected. The dural defect was closed with a fascial patch graft sutured on the dura using this technique, then covered with a vascularized mucoseptal flap. Neither CSF leakage nor meningitis was encountered during the postoperative period.
Conclusion:
The ‘sliding-lock-knot’ technique is simple and useful for dural suturing in microscopic/endoscopic extended TSS. This technique is a helpful tool for preventing CSF leakage after this challenging surgical procedure.
doi:10.4103/2152-7806.107546
PMCID: PMC3589849  PMID: 23493948
Cerebrospinal fluid leakage; extended transphenoidal surgery; fascial patch graft; watertight closure
14.  Responses of intramembranous bone and sutures upon in vivo cyclic tensile and compressive loading 
Bone  2007;42(2):432-438.
Cranial vault and facial sutures interpose between mineralized bones of the skull, and may function analogously to appendicular and cranial base growth plates. However, unlike growth plates that are composed of chondrocyte lineage, cranial and facial sutures possess heterogeneous cell lineages such as mesenchymal cells, fibroblasts, and osteoblasts, in addition to vascular-derived cells. Despite recently intensified effort, the biological responses of intramembranous bone and sutures to mechanical loading are not well understood. This study was designed to investigate whether brief doses of tensile or compressive forces induce modeling and growth responses of intramembranous bone and sutures. In different groups of growing rabbits in vivo, cyclic tensile or compressive forces at 1 Newton and 8 Hz were applied to the maxilla for 20 min/d over 12 consecutive days. Computerized histomorphometric analyses revealed that the average sutural widths of both the premaxillomaxillary suture (PMS) and nasofrontal suture (NFS) loaded in either tension or compression were significantly higher than age- and sex-matched sham controls (P<0.01). The average cell density of tension- or compression-loaded PMS and NFS were significantly higher than sham controls (P<0.01). The average osteoblast occupied sutural bone surface loaded under tension was significantly higher than that of sham control (P<0.05). Interestingly, tensile loading significantly reduced the average osteoclast surface, in comparison to sham control (P<0.05). For the NFS, tensile loading significantly increased the average osteoblast occupied sutural bone surface, in comparison with that of sham control (P<0.05). Also for the NFS suture, compression significantly reduced the average sutural osteoclast surface in comparison with sham control (P<0.05). Taken together, the present data suggest that high-frequency cyclic forces in either tension or compression induce modeling and growth changes in cranial sutures. Due to the structural complexity of cranial vault and facial sutures, either tensile or compressive forces likely are transmitted as shear stresses and upregulate genes and gene products responsible for sutural growth.
doi:10.1016/j.bone.2007.05.014
PMCID: PMC4096789  PMID: 18032124
cranial sutures; forces; osteogenesis; osteoblasts; osteoclasts
15.  A New Method for Hepatic Resection and Hemostasis: Absorbable Plaque and Suture 
Objective:
Blunt and penetrating hepatic injuries are conditions that are frequently encountered in emergency surgeries, and they involve high mortality morbidity. In the handling of such injuries, methods ranging from the application of simple cauterization and suturing for hemostasis to hepatic lobectomies, which might involve the removal of the greater part of the organ, have been defined. Due to the organ’s fragility and susceptibility to bleeding, elective hepatic resections necessitate both surgical experience and technological equipment. Therefore, the demand still exists for an affordable and easy-to-use-method that could be applied by all centers.
Materials and Methods:
To meet this demand, we have developed a method of hemorrhage control via sutures supported by absorbable plaques that provide effective compression and prevent the suture from cutting the tissue during the application of the sutures in the treatment of such fragile organs as the liver.
In our method, we have achieved hemostasis by bilaterally compressing the tissue through strong ties after placing, on the part of the tissue on which the sutures are applied, absorbable and flexible plaques that prevent the suture from cutting the tissue during the application of a polyglactin suture to the solid organ. To prevent dislocation of the plaques, we have fastened the sutures by reeving them through the holes made in the plaques.
Results:
We have demonstrated the success and the practicality of our method by applying it on four pigs; we experimentally inflicted hepatic injuries on two pigs, and we performed resection on the other two pigs. The hepatic hemorrhages we developed in both of the animals were successfully restrained by the use of our method. On the other hand, two resections were performed on the right and left lobes of the other two animals. There were no hemorrhages during the surgery, and the procedure took 45 minutes in total. No postoperative complications occurred. While the liver function test values were high on the seventh day, due to the operation, they were observed to be normal on the thirtieth day. After the laparotomies, performed six months later, we observed that the plaques as well as the sutures were absorbed and that the injured tissues were completely healed. Additionally, it was observed during the pathological examination that the tissues beneath the area of application were healed through fibrosis and that the liver had no other pathologies.
Conclusions:
In conclusion, we believe that the method can be safely used in hepatic resections or traumatic hemorrhages in the proper locations.
doi:10.5152/eajm.2010.01
PMCID: PMC4261311  PMID: 25610107
Hepatic resection; Hepatic trauma; Plaque and suture
16.  Unique Modulation of Cadherin Expression Pattern during Posterior Frontal Cranial Suture Development and Closure 
Cells, Tissues, Organs  2009;191(5):401-413.
Cranial suture development involves coordinated expression of multiple genes and tissue contribution from neural crest cells and paraxial mesoderm for timely sutural morphogenesis. Transcription factors, growth factors, and neural crest determinant genes play critical roles in calvarial growth ensuring normal development of the underlying brain. In vitro studies have implicated cell-cell adhesion molecules as a driving force behind suture closure. We performed cDNA microarray to study differential expression of adhesion molecules during the timing of suture closure in a mouse model where only the posterior frontal (PF) suture closes. Our results indicate increased expression of E-cadherin during the period of PF suture closure. Quantitative RT-PCR analysis of E- and N-cadherin in PF closing suture revealed a biphasic expression of N-cadherin, the first phase coinciding with cellular condensation preceding chondrogenesis followed by a second phase coinciding with E-cadherin co-expression and suture closure. Furthermore, expression analysis of the N-cadherin and E-cadherin transcriptional repressors Wnt7a and Snail indicate a specific temporal regulation of these genes, suggesting their potential role as regulators of both E- and N-cadherin during the PF suture development and closure. Finally, given the in vitro evidence of fibroblast growth factor (FGF)-2 as a potential regulator of E- and N-cadherin we investigated the expression of E-cadherin during PF suture closure in Fgf-2 deficient mice. In contrast to in vitrodata previously reported, E-cadherin expression is normal in these animals, and PF suture closure occurs properly, probably due to potential redundancy of FGF ligands ensuring normal temporal expression of E-cadherin and PF suture closure.
doi:10.1159/000272318
PMCID: PMC2859230  PMID: 20051668
Cranial Suture; Closure; E-cadherin; N-cadherin; Development; FGF-2; Mouse
17.  Absorbable Versus Silk Sutures for Surgical Treatment of Trachomatous Trichiasis in Ethiopia: A Randomised Controlled Trial 
PLoS Medicine  2011;8(12):e1001137.
In this randomized trial, Saul Rajak et al. compare silk sutures (removed at 7–10 days) or absorbable sutures (left in place) during surgery for the management of trachomatous trichiasis.
Background
Trachoma causes blindness through an anatomical abnormality called trichiasis (lashes touching the eye). Trichiasis can recur after corrective surgery. We tested the hypothesis that using absorbable sutures instead of silk sutures might reduce the risk of recurrent disease among patients with major trichiasis in a randomised trial.
Methods and Findings
1,300 individuals with major trichiasis from rural villages in the Amhara Region of Ethiopia were recruited and assigned (1∶1) by computer-generated randomisation sequence to receive trichiasis surgery using either an absorbable suture (polyglactin-910) or silk sutures (removed at 7–10 days) in an otherwise identical surgical technique. Participants were examined every 6 months for 2 years by clinicians masked to allocation. The primary outcome measure was recurrent trichiasis (≥one lash touching the eye) at 1 year. There was no difference in prevalence of recurrent trichiasis at 1 year (114 [18.2%] in the absorbable suture group versus 120 [19.7%] in the silk suture group; odds ratio = 0.90, 95% CI 0.68–1.20). The two groups also did not differ in terms of corneal opacification, visual acuity, conjunctival inflammation, and surgical complications.
Conclusions
There was no evidence that use of absorbable polyglactin-910 sutures was associated with a lower prevalence of trichiasis recurrence at 1 year postsurgery than silk sutures. However, from a programmatic perspective, polyglactin-910 offers the major advantage that patients do not have to be seen soon after surgery for suture removal. The postoperative review after surgery using absorbable polyglactin-910 sutures can be delayed for 3–6 months, which might allow us to better determine whether a patient needs additional surgery.
Trial registration
ClinicalTrials.gov NCT00522860
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Globally, around 40 million people—mostly people living in rural areas in developing countries where there are water shortages, poor personal hygiene, and crowded living conditions—have active trachoma, an infectious eye disease that is caused by Chlamydia trachomatis. This bacterium is spread through contact with infected eye secretions or with contaminated towels or clothes, and by flies. Recurrent infections with C. trachomatis during early childhood cause inflammation of the tissue lining the eye lid (chronic conjunctival inflammation), which can lead to conjunctival scarring. If this scarring is severe, the eyelids turn inwards (entropion) and the lashes rub across the eye's surface (the cornea). This condition—trachomatous trichiasis—is extremely painful and, if not treated with surgery, can lead to irreversible corneal opacities and visual impairment by middle age. It is estimated that 8 million people have trichiasis and that an additional 8 million people are blind or visually impaired as a result of the condition.
Why Was This Study Done?
Surgery for trichiasis, antibiotics for infection, and facial cleanliness and environmental improvements to reduce transmission together constitute the SAFE strategy for the control of blinding trachoma. Unfortunately, trichiasis recurs in nearly two-thirds of patients within 3 years of surgery, often within the first year. How the surgery is performed, its quality, and the severity of entropion and conjunctival scarring at the time of surgery all contribute to trichiasis recurrence. In this randomized trial (a study in which randomly chosen groups of patients receive different treatments for a disease and are followed to compare the outcomes of these interventions), the researchers investigate whether using absorbable sutures instead of silk sutures reduces the risk of recurrent disease among patients with major trichiasis (more than five lashes touching the cornea). Sutures are used to sew up surgical incisions. Silk sutures, which are used routinely during trichiasis surgery, have to be removed 7–10 days after surgery when the incision may not have stably healed. Absorbable sutures might provide more stable fixation of the eye tissue while healing is taking place and might, therefore, reduce the recurrence of trichiasis after surgery.
What Did the Researchers Do and Find?
The researchers randomly assigned 1,300 people living in Ethiopia (the country with the highest rates of trachoma and trichiasis) to receive trichiasis surgery using silk sutures (removed at 7–10 days) or absorbable sutures (left in place); the other details of the surgery were identical for all the patients. The trial's primary outcome was recurrent trichiasis (one or more lash touching the eye) at 1 year. Secondary outcomes included the rate of recurrence, visual acuity, corneal opacity, and conjunctival inflammation at 2 years, and surgical complications. At 1 year, 18.2% of the patients in the absorbable suture group and 19.7% in the silk suture group had developed recurrent trichiasis. That is, the prevalence of recurrence in the two groups was similar. There was also no difference in the rate of trichiasis recurrence between the groups 2 years after surgery. Moreover, the two groups did not differ in terms of corneal opacity and visual acuity, conjunctival inflammation, or surgical complications.
What Do These Findings Mean?
These findings provide no evidence to suggest that the use of absorbable sutures during trichiasis surgery is clinically better than the use of silk sutures. However, the researchers note that the use of absorbable sutures would eliminate the need for patients to return to the clinic soon after their operation to have their sutures removed. In remote rural settings, it can be difficult for patients, who are often elderly and poor, to attend clinics. Thus, it might be better for trachoma services to concentrate on encouraging patients to return 3–6 months after surgery when the need for additional surgery can be determined rather than trying to encourage them to come back after 7–10 days for suture removal. The use of absorbable sutures would also avoid any complications arising from patients failing to come back to have their stitches removed. The researchers suggest, therefore, that trachoma control programs should now consider the potential logistical advantages of using absorbable sutures rather than silk sutures during trichiasis surgery despite the lack of any apparent clinical difference between the two suture types.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001137.
An accompanying PLoS Medicine Research Article by Saul Rajak et al. describes another randomized trial undertaken by these researchers that compares surgery and epilation (eyelash removal) for the treatment of trichiasis in Ethiopia
The World Health Organization has information on trachoma (in several languages), including details of the Alliance for Global Elimination of Trachoma by the year 2020 (GET 2020) and a personal story about blinding trachoma
The UK National Health Service Choices website also provide information on trachoma
Orbis, an international nonprofit organization devoted to blindness prevention and treatment in developing countries, provides information about trachoma
The International Trachoma Initiative provides detailed information about trachoma and a personal story about trichiasis surgery in Ethiopia
The Global Atlas of Trachoma is an open-access resource on the geographical distribution of trachoma
Light for the World is a nonprofit organization dedicated to ensuring the rights of persons with disabilities in developing countries, including people in Ethiopia with trachoma
doi:10.1371/journal.pmed.1001137
PMCID: PMC3236737  PMID: 22180732
18.  Midurethral Slings for Women with Stress Urinary Incontinence 
Executive Summary
Objective
The objective of the current review was to evaluate the safety, efficacy, and cost-effectiveness of midurethral slings compared with traditional surgery.
Background
This assessment was undertaken in order to update and expand upon the health technology & policy assessment of tension-free vaginal tape (TVT, Gynecare Worldwide, a division of Ethicon Inc, a Johnson & Johnson company, Somerville, New Jersey) sling procedure for stress urinary incontinence published by the Medical Advisory Secretariat in February 2004. Since the publication of the 2004 assessment, a number of TVT-like sling alternatives have become available which employ the same basic principles as TVT slings: minimally invasive, midurethral placement, self-fixing, and tension-free. This update will evaluate the efficacy and safety of midurethral slings.
Clinical Need
Normal continence is controlled by the nervous system and involves co-ordination between bladder, urethra, urethral sphincter, and pelvic floor. Incontinence occurs when the relationship among the above components is compromised, either due to physical damage or nerve dysfunction. (1) Stress urinary incontinence is the most common form of urinary incontinence in women. It is characterized by the “complaint of involuntary leakage on effort or exertion, or on sneezing or coughing” when there is increased abdominal pressure without detrusor (bladder wall) contraction. (2) There are 2 factors which define stress urinary incontinence: a weakening in the support of the proximal urethra, causing urethral hyper-mobility and deficiency in the sphincter, causing urethral leakage. Both factors are thought to coexist. (1) Accurate tests are not available to distinguish these 2 types of stress urinary incontinence.
Urinary incontinence is estimated to affect about 250,000 Canadian women and 8 million American women aged 65 and over. (3;4) The prevalence of stress urinary incontinence is very difficult to measure because women with stress urinary incontinence may not tell their health practitioner about their symptoms due to embarrassment associated with stress urinary incontinence. A cross-sectional postal survey of 15,904 adults aged 40 and over who were registered with a local GP in Leicestershire, United Kingdom, revealed that 18% to 34% of respondents had symptoms of SUI. (5) Just over 9% reported symptoms “sometimes,” while almost 3% reported symptoms “most of the time.” Stress urinary incontinence was most common for women in their 50s. A more recent study suggests that 24% of women aged 18 to 44 years and 37% of women aged 45 and over have symptoms of stress urinary incontinence. (6)
Stress urinary incontinence has been associated with a broad range of psychosocial stress and disablement, such as difficulties with activities of daily living, avoidance of social activities, fear of unpleasant odour, and embarrassment. (7) Economic burden may include the cost of pads, drugs, and devices, and the inability to participate in the work force in severe cases.
Midurethral Slings
Suburethral slings differ according to several criteria including placement, approach, method of fixation, and sling material. This review will evaluate slings which fulfill all of the following criteria:
Midurethral placement (as opposed to bladder neck placement)
Self-fixing (no sutures, bone anchors, etc.)
Minimally invasive (using local, epidural, or general anesthesia)
“Tension-free” placement
The different types of midurethral slings available vary according to 3 main parameters:
Implant material, i.e., monofilament, multifilament, elastic, non-elastic, smooth, serrated, etc.,
Delivery instruments, i.e., needles, curved trocars, disposable, reusable, etc.,
Surgical approach
As any one, or any combination of these parameters may vary across the different sling brands, it is difficult to ascribe observed differences in efficacy and safety across slings to any one factor.
Review Strategy
The literature published between January 2000 and February 2006 was searched in the following databases: OVID Medline, In Process and Other Non-Indexed Citations, Embase, Cochrane Database of Systematic Reviews and CENTRAL, INAHTA. The database search was supplemented with a search of relevant Web sites, and a review of the bibliographies of selected papers. The search strategy can be viewed in Appendix 1.
Inclusion Criteria
General population with SUI
Randomized controlled studies, health technology assessments, guidelines
Female subjects
Midurethral, self-fixing, and minimally invasive slings/tapes
English language
The search strategy yielded 391 original citations. Studies were excluded for a variety of reasons, such as using traditional, suburethral slings as opposed to midurethral slings, not including patients with stress urinary incontinence, including males in the study, case reports, and not reporting the outcomes of interest.
There were 13 randomized controlled trials identified that compared midurethral slings to other midurethral slings or traditional surgery. (8-20) (Table 1) Three of the randomized controlled trials (15;17;20) have had subsequent updated articles of longer term results. (21-23) The results of the randomized controlled trials have been stratified into 2 groups: TVT versus colposuspension and comparisons of midurethral slings. No randomized controlled trials were identified that compared a midurethral sling other than TVT to colposuspension.
Summary of Findings
Effectiveness
At this time, there does not appear to be one procedure that is more effective than another at curing stress urinary incontinence. TVT appears to have similar cure rates to open colposuspension; and the various midurethral sling types seem to have similar cure rates.
Procedure Time and Length of Hospital Stay
The procedure time and the length of hospital stay for TVT are significantly shorter than the procedure time and length of stay for colposuspension.
The procedure time and length of hospital stay for all midurethral slings appears to be similar.
Complications
The most frequently reported complications were bladder perforations, de novo voiding difficulties and device problems.
Quality of Life
Quality of life was not consistently reported in all of the randomized controlled trials. In the studies that reported quality of life there does not appear to be a significant difference in quality of life scores between the sling procedures.
PMCID: PMC3379163  PMID: 23074494
19.  Tensile strength of a surgeon’s or a square knot 
Journal of surgical education  2010;67(4):222-226.
Objective
To test the integrity of surgeon’s knots and flat square knots using four different suture materials.
Study Design
Chromic catgut, polyglactin 910, silk, and polydioxanone sutures were tied in the two types of knot configurations. For all sutures, a 0-gauge United States Pharmacopeia suture was used. Knots were tied by a single investigator (JB). Suture was soaked in 0.9 % sodium chloride for 60 seconds and subsequently transferred to a tensiometer where the tails were cut to 3 mm length. We compared the knots, measuring knot strength using a tensiometer until the sutures broke or untied.
Results
A total of 119 knots were tied. We found no difference in mean tension at failure between a surgeon’s knot (79.7 Newtons) and a flat square knot (82.9 Newtons). Using a Chi-square test, we did not find a statistically significant difference in the likelihood of knots coming untied between surgeon’s knots (29%) and flat square knots (38%).
Conclusions
Under laboratory conditions, surgeon’s knots and flat square knots did not differ in tension at failure or likelihood of untying.
doi:10.1016/j.jsurg.2010.06.007
PMCID: PMC4167833  PMID: 20816357
Suture Techniques; Tensile Strength; Suture end length; Polyglactin 910
20.  Parallel alternating sliding knots are effective for ligation of mesenteric arteries during resection and anastomosis of the equine jejunum 
BMC Veterinary Research  2014;10(Suppl 1):S10.
Background
In literature only one article describes and compares methods of achieving hemostasis in equine mesenteric arteries during jejunal resection and anastomosis, and most textbooks favor ligating-dividing mechanical devices. The latter method cannot always be used, not least because the devices are expensive and in some cases even contra-indicated. Various types of knots, including sliding knots, are widely used to provide hemostasis in laparoscopy.
The objective of this study was to compare a triple ligature for mesenteric vessels composed of three sliding knots with a triple ligature composed of a modified transfixing and two surgeon’s knots.
Methods
Portions of jejunum with associated mesenteric vessels were collected from 12 horses at a local abattoir. These were divided into 24 specimens containing five mesenteric arteries each. Each artery was closed with a triple ligature. In group A, a surgeon’s knot was used to tie the ligatures (two circumferential and one modified transfixing) while in group B all ligatures (three circumferential) were tied with a parallel alternating sliding knot. Both groups were divided ino two subgroups depending on suture material used (multifilament or monofilament suture material). Time to perform ligatures for every specimen were recorded and compared between groups.
After closure, arteries were cannulated and intraluminal pressures were increased until ligature failure. Leaking pressures were recorded and compared between groups.
Results
Ligation of mesenteric arteries was significantly faster to perform with sliding knots than with surgeon’s knots, both with monofilament and multifilament suture material. With multifilament suture material, the leaking pressure of sliding knot ligatures was significantly higher than that of surgeon’s knot ligatures. With monofilament suture, there were no statistically significant differences in leaking pressure between ligature methods. Both ligating methods were stronger with monofilament suture material than with multifilament suture material.
Conclusions
Regardless of the ligature used, monofilament suture material performed better than multifilament suture material to achieve hemostatic knots. Independently of the suture material, the sliding knot is comparable or better than the surgeon’s knot in providing hemostasis, and is faster to perform.
doi:10.1186/1746-6148-10-S1-S10
PMCID: PMC4122897  PMID: 25238115
21.  The TopClosure® 3S System, for skin stretching and a secure wound closure 
The principle of stretching wound margins for primary wound closure is commonly practiced and used for various skin defects, leading at times to excessive tension and complications during wound closure. Different surgical techniques, skin stretching devices and tissue expanders have been utilized to address this issue. Previously designed skin stretching devices resulted in considerable morbidity. They were invasive by nature and associated with relatively high localized tissue pressure, frequently leading to necrosis, damage and tearing of skin at the wound margins. To assess the clinical effectiveness and performance and, to determine the safety of TopClosure® for gradual, controlled, temporary, noninvasive and invasive applications for skin stretching and secure wound closing, the TopClosure® device was applied to 20 patients for preoperative skin lesion removal and to secure closure of a variety of wound sizes. TopClosure® was reinforced with adhesives, staples and/or surgical sutures, depending on the circumstances of the wound and the surgeon’s judgment. TopClosure® was used prior to, during and/or after surgery to reduce tension across wound edges. No significant complications or adverse events were associated with its use. TopClosure® was effectively used for preoperative skin expansion in preparation for dermal resection (e.g., congenital nevi). It aided closure of large wounds involving significant loss of skin and soft tissue by mobilizing skin and subcutaneous tissue, thus avoiding the need for skin grafts or flaps. Following surgery, it was used to secure closure of wounds under tension, thus improving wound aesthetics. A sample case study will be presented. We designed TopClosure®, an innovative device, to modify the currently practiced concept of wound closure by applying minimal stress to the skin, away from damaged wound edges, with flexible force vectors and versatile methods of attachment to the skin, in a noninvasive or invasive manner.
doi:10.1007/s00238-011-0671-1
PMCID: PMC3375424  PMID: 22719176
Wound closure; Skin stretching; Tissue expansion; Viscoelastic properties of skin; Mechanical creep; Stress relaxation
22.  Effect of Surgical Technique on Corneal Implant Performance 
Purpose
Our aim was to determine the effect of a surgical technique on biomaterial implant performance, specifically graft retention.
Methods
Twelve mini pigs were implanted with cell-free, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) cross-linked recombinant human collagen type III (RHCIII) hydrogels as substitutes for donor corneal allografts using overlying sutures with or without human amniotic membrane (HAM) versus interrupted sutures with HAM. The effects of the retention method were compared as well as the effects of collagen concentration (13.7% to 15% RHCIII).
Results
All implanted corneas showed initial haze that cleared with time, resulting in corneas with optical clarity matching those of untreated controls. Biochemical analysis showed that by 12 months post operation, the initial RHCIII implants had been completely remodeled, as type I collagen, was the major collagenous protein detected, whereas no RHCIII could be detected. Histological analysis showed all implanted corneas exhibited regeneration of epithelial and stromal layers as well as nerves, along with touch sensitivity and tear production. Most neovascularization was seen in corneas stabilized by interrupted sutures.
Conclusions
This showed that the surgical technique used does have a significant effect on the overall performance of corneal implants, overlying sutures caused less vascularization than interrupted sutures.
Translational Relevance
Understanding the significance of the suturing technique can aid the selection of the most appropriate procedure when implanting artificial corneal substitutes. The same degree of regeneration, despite a higher collagen content indicates that future material development can progress toward stronger, more resistant implants.
doi:10.1167/tvst.3.2.6
PMCID: PMC3988835  PMID: 24749003
biosynthetic cornea; corneal regeneration; biomaterials; recombinant human collagen; corneal transplantation
23.  Effect of Implantation on engineered skeletal muscle constructs 
The development of engineered skeletal muscle would provide a viable tissue for replacement and repair of muscle damaged by disease or injury. Current tissue engineering methods result in three-dimensional (3-D) muscle constructs that generate tension, but do not advance phenotypically beyond neonatal characteristics (Larkin et al., 2006). To develop to an adult phenotype, innervation and vascularization of the construct must occur. In this study, 3-D muscle constructs were implanted into the hindlimb of a rat along the sciatic nerve with the sural nerve isolated, transected and sutured to the construct to encourage innervation. Aortic ring anchors were sutured to the tendons of the biceps femoris muscle so that the construct would move dynamically with the endogenous muscle. After 1 week in vivo, constructs were explanted, evaluated for force production, and stained for muscle, nerve, and collagen markers. Implanted muscle constructs showed a developing capillary system, an epimysium-like outer layer of connective tissue, and an increase in myofiber content. The beginning of alpha-bungarotoxin clustering suggests that neuromuscular junctions (NMJ) could form on the implanted muscle given more time in vivo. Additionally, the constructs increased maximum isometric force from 192±41μN to 549±103μN (245% increase) compared to in vitro controls that increased from 276±23μN to 329±27μN (25% increase). These findings suggest that engineered muscle tissue survives 1 week implantation and begins to develop the necessary interfaces needed to advance the phenotype toward adult muscle. However, in terms of force production, the muscle constructs need longer implantation times to fully develop an adult phenotype.
doi:10.1002/term.537
PMCID: PMC3355234  PMID: 22328229
tissue engineering; implantation; skeletal muscle; innervation; vascularization
24.  Anatomical and biomechanical evaluation of the tension band technique in patellar fractures 
International Orthopaedics  2008;33(4):1113-1117.
Tension band wiring for patellar fractures is common, but some recent reports refer to disadvantages of this approach. Our anatomical and biomechanical study focused on use of tension band techniques in patellar fractures. The anatomy of the patella and tendon insertion was examined with knee magnetic resonance imaging (MRI) and correlated with the technical requirements of the tension band. Tension band wiring over tendinous tissue was simulated and calculated with a cyclic biomechanical test on cow patellae. According to tension band templating on the MRI section, Kirschner wire insertion was needed for the tension band to turn over the tendinous tissue. The tension band became more stable while turning over less tendinous tissue and more adjacent bone surface. Nevertheless, cyclic loading tests indicate that all tension band applications in this study lose their initial stability. Excessive initial compression by the tension band resulted in bending of the Kirschner wire and thus reduction failure. For optimum stabilisation, tension force transfer should be done directly on bone or at least material that protects the tendon would be useful.
doi:10.1007/s00264-008-0602-3
PMCID: PMC2898995  PMID: 18618113
25.  Left ventricle remodelling by double-patch sandwich technique 
Background
The sandwich double-patch technique was adopted as an alternative method for reconstruction of the left ventricle after excision of postinfarction dysfunctional myocardium to solve technical problems due to the thick edges of the ventricular wall.
Methods
Over a 5-year period, 12 of 21 patients with postinfarction antero-apical left ventricular aneurysm had thick wall edges after wall excision. It was due to akinetic muscular thick tissue in 6 cases, while in the other 6 with classic fibrous aneurysm, thick edges remained after the cut of the border zone. The ventricular opening was sandwiched between two patches and this is a technique which is currently used for the treatment of the interventricular septum rupture. In our patients the patches are much smaller than the removed aneurysm and they were sutured simply by a single row of single stitches. However, in contrast to interventricular septum rupture where the patches loosen the tension of the tissues, in our patients the patches pull strongly and restrain the walls by fastening their edges and supporting tight stitches. In this way they could narrow the cavity and close the ventricle.
Results
The resected area varied from 5 × 4 to 8 × 8 cm. Excision was extended into the interventricular septum in 5 patients, thus opening the right ventricle. CABG was performed on all patients but two. Left ventricular volumes and the ejection fraction changed significantly: end-systolic volume 93.5 ± 12.4 to 57.8 ± 8.9 ml, p < 0.001; end-diastolic volume 157.2 ± 16.7 to 115.3 ± 14.9 ml, p < 0.001; ejection fraction 40.3 ± 4.2 to 49.5 ± 5.7%, p < 0.001. All patients did well. One patient suffered from bleeding, which was not from the wall suture, and another had a left arm paresis. The post-operative hospital stay was 5 to 30 days with a mean 10.5 ± 7.5 days/patient. At follow-up, 9 to 60 months mean 34, all patients were symptom-free. NYHA class 2.5 ± 0.8 changed to 1.2 ± 0.4, p < 0.001.
Conclusion
The double-patch sandwich technique (bi-patch closure) offers some advantages and does not result in increased morbidity and mortality. In the case of excising a left ventricular aneurysm, this technique in no way requires eversion of the edges, felt strips, buttressed and multiple sutures, all of which are needed for longitudinal linear closure. Moreover, it does not require purse string sutures, endocardial scar remnant to secure the patch or folding the excluded non-functional tissue, all of which are needed for endoventricular patch repair.
doi:10.1186/1749-8090-2-10
PMCID: PMC1803783  PMID: 17266754

Results 1-25 (911714)