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1.  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.
PMCID: PMC3049425  PMID: 21436874
2.  Arthroscopic Glenoid Labral Repair With an Oblique Mattress Configuration 
Arthroscopy Techniques  2013;2(3):e281-e283.
There have been several arthroscopic techniques described in the literature regarding the passage of sutures for an arthroscopic glenoid labral repair. With simple suture passage when tying knots, there is a concern of internal knot impingement, especially in the posterosuperior labrum. On the other hand, with simple suture passage with knotless technology, there is a concern of leaving the anchor hole exposed in the glenohumeral joint space, especially with anchors that are degradable over time. Whereas a horizontal mattress configuration may address these 2 issues in most cases, there is the issue of tissue cut-through with the labral tissue fibers being in the same plane as the horizontal mattress sutures. The purpose of this report is to describe the oblique mattress configuration, which allows the passage of suture through multiple labral tissue planes, covers up the anchor holes with labral tissue, and maintains the knots away from the articular surface if knots are tied.
PMCID: PMC3834891  PMID: 24265999
3.  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.
PMCID: PMC2789259  PMID: 16690062
Mechanical testing; Compression; Tension; Facial suture
4.  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.
PMCID: PMC2813870  PMID: 10521876
sutures; mastication; bone strain; skull; growth; miniature swine
5.  The history and evolution of sutures in pelvic surgery 
The purpose of the study is to review the history and innovations of sutures used in pelvic surgery. Based on a review of the literature using electronic- and hand-searched databases we identified appropriate articles and gynaecology surgical textbooks regarding suture for wound closure. The first documented uses of suture are explored and then the article focuses on the use of knotted materials in pelvic surgery. The development of suture of natural materials is followed chronologically until the present time where synthetic suture is implanted during countless surgeries every day. This millennial history of suture contains an appreciation of the early work of Susruta, Celsus, Paré and Lister, including a survey of some significant developments of suture methods over the last 100 years. Most surgeons know little about the history and science of sutures. A retrospective view of suture is critical to the appreciation of the current work and development of this common tool.
PMCID: PMC3046193  PMID: 21357979
6.  An In Vitro and In Vivo Evaluation of Tensile Strength and Durability of Seven Suture Materials in Various pH and Different Conditions: An Experimental Study in Rats 
The Indian Journal of Surgery  2010;72(5):386-390.
Development in material engineering provide many kinds of suture materials to medical fields. The choice of utilization depends on the surgeons decision, the durability, absorbtion times, tensile strength of the suture, and operation site in means of organ and tissue. In this study we aimed to investigate 7 different suture materials in vivo and in vitro conditions to evaluate the properties and durability. Basal tensile strength (TS) values of all sutures were measured and 168 Wistar albino rats were utilised in vivo groups. The sutures were placed in the bladder, stomach, intestine and bile duct (after obstructive jaundice). Urine and bile of rat, pH 1 and pH 10 were used as in vitro conditions. Seven different suture materials (Maxon, Vicryl, Plain Catgut, Surgical Silk, Polypropylene, Caprosyn and Biosyn) were investigated in 9 different in vitro and in vivo conditions. All sutures were chosen to be in size 5/0. In the following 5th day the sutures were tested related to durability and stability. Results were compared stastically using the Mann-Whitney U test and p < 0.05 was considered as stastically significant. Among all the suture materials only polypropylene proved to preserve its stability in vivo and in vitro surveys. Cat-gut and caprosyn lost its TS in all medias. Silk and biosyn lost its TS in all conditions except the stomach and intestines. Maxon also lost its TS in all condition except urine. Utilisation of caprosyn and biosyn in urinary procedures reduces stone formation and infections. The suture of choice in biliary tract should be vicryl, maxon or biosyn since polypropylene preserves its stability that could result in stone formation. In intestinal operations polypropylene, vicryl, and silk could be preferred.
PMCID: PMC3077148  PMID: 21966138
Suture materials; In vitro; In vivo conditions
7.  Bidirectional Barbed Sutures for Wound Closure: Evolution and Applications 
Traditionally, wound closure sutures have in common the need to tie knots with the inherent risk of extrusion, palpability, microinfarcts, breakage, and slippage. Bidirectional barbed sutures have barbs arrayed in a helical fashion in opposing directions on either side of an unbarbed midsegment. This suture is inserted at the midpoint of a wound and pulled through till resistance is encountered from the opposing barbs; each half of the suture is then advanced to the lateral ends of the wound. This design provides a method of evenly distributing tension along the incision line, a faster suture placement and closure time with no need to tie knots, and the possibility of improved cosmesis. Bidirectional barbed sutures, which are available in both absorbable and nonabsorbable forms, can be used for simple closures, multilayered closures, and closure of high-tension wounds in a variety of surgical settings.
PMCID: PMC3478908  PMID: 24527114
Bidirectional barbed sutures; Wound closure
8.  Comparative trial of Dexon (polyglycolic acid), collagen, and silk sutures in ophthalmic surgery. 
The tissue reaction, absorption, and handling properties of Dexon synthetic absorbable sutures, which are made from polymerized hydroxyacetic acid, were compared with those of silk and collagen in 51 eye operations, consisting mainly of cataract extractions and squint corrections. There was no significant difference between the sutures as regards degree of tissue reaction. The Dexon sutures were very strong and the knots held well. The sizes used in this series were found to be a little too thick and stiff for use in micro-surgery; smaller sizes would be easier to use and still remain strong enough. The Dexon was reliably absorbed in 5 weeks on average. No serious adverse reactions were seen with any of the sutures. Dexon was as well tolerated as the control sutures but had the advantage over silk of being absorbed and over collagen of containing no foreign protein.
PMCID: PMC1017446  PMID: 766826
9.  Application of Haptic Feedback to Robotic Surgery 
Robotic surgical systems have greatly contributed to the advancement of minimally invasive endoscopic surgery. However, current robotic systems do not provide tactile or haptic feedback to the operating surgeon. Under certain circumstances, particularly with the manipulation of delicate tissues and suture materials, this may prove to be a significant irritation. We hypothesize that haptic feedback, in the form of sensory substitution, facilitates the performance of surgical knot tying. This preliminary study describes evidence that visual sensory substitution permits the surgeon to apply more consistent, precise, and greater tensions to fine suture materials without breakage during robot-assisted knot tying.
PMCID: PMC1283126  PMID: 15245675
10.  Early Experience With Barbed Sutures for Abdominal Closure in Deep Inferior Epigastric Perforator Flap Breast Reconstruction 
Eplasty  2012;12:e24.
Objective: Barbed sutures have recently been introduced for closure of surgical incisions. These self-anchoring sutures incorporate evenly spaced barbs in a circumferential distribution along their length, facilitating knotless wound closure and even distribution of tension along the suture line. In this study, we evaluated postoperative complications associated with the use of unidirectional barbed sutures compared with standard sutures for closure of the abdominal incision in deep inferior epigastric perforator flap breast reconstruction. Methods: A consecutive series of 142 patients undergoing deep inferior epigastric perforator flap breast reconstruction were identified at a single institution. The abdominal closure in the first 71 patients was performed using standard suture materials. In the subsequent 71 patients, closure was performed using unidirectional barbed sutures. Patient demographics, complications, procedure time, and costs were compared between standard and barbed suture groups. Results: Demographic characteristics and comorbidity profiles were similar between the 2 groups. Overall, there was a significantly higher incidence of complications in the standard suture group (17 vs 7 complications,P = .0423). Similar rates of wound infection (P = .4412), wound dehiscence (P = .4934), and seroma (P = .1157) were recorded in both groups. Barbed sutures were $ 15.58 more expensive than standard sutures. No significant difference in total length of operation was observed. Conclusion: In this study, the utility of unidirectional barbed sutures in deep inferior epigastric perforator flap breast reconstruction has been demonstrated. Barbed sutures may be useful in a broad range of plastic surgery procedures, not only because of their convenience but also based on favorable clinical outcomes.
PMCID: PMC3359151  PMID: 22662282
11.  Useful ‘sliding-lock-knot’ technique for suturing dural patch to prevent cerebrospinal fluid leakage after extended transsphenoidal surgery 
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.
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.
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.
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.
PMCID: PMC3589849  PMID: 23493948
Cerebrospinal fluid leakage; extended transphenoidal surgery; fascial patch graft; watertight closure
12.  Cranial Sutures and Bones: Growth and Fusion in Relation to Masticatory Strain 
Cranial bones and sutures are mechanically loaded during mastication. Their response to masticatory strain, however, is largely unknown, especially in the context of age change. Using strain gages, this study investigated masticatory strain in the posterior interfrontal and the anterior interparietal sutures and their adjacent bones in 3- and 7-month-old miniature swine (Sus scrofa). Double-fluorochrome labeling of these animals and an additional 5-month group was used to reveal suture and bone growth as well as features of suture morphology and fusion. With increasing age, the posterior interfrontal suture strain decreased in magnitude and changed in pattern from pure compression to both compression and tension, whereas the interparietal suture remained in tension and the magnitude increased unless the suture was fused. Morphologically, the posterior interfrontal suture was highly interdigitated at 3 months and then lost interdigitation ectocranially in older pigs, whereas the anterior interparietal suture remained butt-ended. Mineralization apposition rate (MAR) decreased with age in both sutures and was unrelated to strain. Bone mineralization was most vigorous on the ectocranial surface of the frontal and the parietal bones. Unlike the sutures, with age bone strain remained constant while bone MARs significantly increased and were correlated with bone thickness. Fusion had occurred in the interparietal suture of some pigs. In all cases fusion was ectocranial rather than endocranial. Fusion appeared to be associated with increased suture strain and enhanced bone growth on the ectocranial surface. Collectively, these results indicate that age is an important factor for strain and growth of the cranium.
PMCID: PMC2813868  PMID: 14752854
cranial suture; masticatory strain; skull growth; pig
13.  Analysis and Physics of Laparoscopic Intracorporeal Square-Knot Tying 
Square knots are often used in open surgery to approximate tissue borders or tie off tubular structures like vessels or ducts. Three common methods are used for surgical square-knot tying: one-hand tying, two-hand tying, and the instrument-tying technique. Two types of suture placements are studied in both the open and laparoscopic surgical fields. The first called equal length has suture segment ends placed at equal distances from the tying site. The second called unequal length has one suture end further away from the tying site than the other. Laparoscopic intracorporeal square-knot tying maneuvers are analyzed herein. Mechanical analysis of square-knot tying movements reveals that regardless of location or method used in construction, all square knots consist of 2 half-knots. For study purposes, these sets of movements are identified in laparoscopy as maneuver A and maneuver B. Further breakout of these maneuvers reveals that they consist of 5 motions. This study reveals that 16 different ways exist to place a square knot by means of the laparoscopic intracorporeal technique. It is likely that difficulty mastering this essential skill is not just the result of poor instrumentation, improper port placement, or the limitations of a 2-dimensional video image. It may also be attributed to mixing up the different square-knot tying techniques during random practice exercises. This is possible if the surgeon is ignorant of the technical variations present in what most people consider a simple task.
PMCID: PMC3015543  PMID: 15791984
Laparoscopic square-knot tying; Laparoscopic physics; Laparoscopic education; Laparoscopic trainer; Pelvic trainer
14.  Technical Refinements in Single-Port Laparoscopic Surgery of Inguinal Hernia in Infants and Children 
The techniques of minimal access surgery for pediatric inguinal hernia are numerous and they continue to evolve, with a trend toward increasing use of extracorporeal knotting and decreasing use of working ports and endoscopic instruments. Single-port endoscopic-assisted percutaneous extraperitoneal closure seems to be the ultimate attainment, and numerous techniques have mushroomed in the past decade. This article comprehensively reviews and compares the various single-port techniques. These techniques mainly vary in their approaches to the hernia defect with different devices, which are designed to pass a suture to enclose the orifice of the defect. However, most of these emerging techniques fail to entirely enclose the hernia defect and have the potential to lead to higher incidence of hernia recurrence. Accompanying preperitoneal hydrodissection and keeping identical subcutaneous path for introducing and withdrawing the suture, the suture could tautly enclose the hernia defect without upper subcutaneous tissues and a lower peritoneal gap, and a trend towards achieving a near-zero recurrence rate.
PMCID: PMC2874921  PMID: 20508740
15.  Traditional Chinese surgical treatment for anal fistulae with secondary tracks and abscess 
AIM: To evaluate the efficacy and safety of traditional Chinese surgical treatment for anal fistulae with secondary tracks and abscess.
METHODS: Sixty patients with intersphincteric or transsphincteric anal fistulas with secondary tracks and abscess were randomly divided into study group [suture dragging combined with pad compression (SDPC)] and control group [fistulotomy (FSLT)]. In the SDPC group, the internal opening was excised and incisions at external openings were made for drainage. Silk sutures were put through every two incisions and knotted in loose state. The suture dragging process started from the first day after surgery and the pad compression process started when all sutures were removed as wound tissue became fresh and without discharge. In the FSLT group, the internal opening and all tracts were laid open and cleaned by normal saline postoperatively till all wounds healed. The time of healing, postoperative pain score (visual analogue scale), recurrence rate, patient satisfaction, incontinence evaluation and anorectal manometry before and after the treatment were examined.
RESULTS: There were no significant differences between the two groups regarding age, gender and fistulae type. The time of healing was significantly shorter (24.33 d in SDPC vs 31.57 d in FSLT, P < 0.01) and the patient satisfaction score at 1 mo postoperative follow-up was significantly higher in the SDPC group (4.07 in SDPC vs 3.37 in FSLT, P < 0.05). The mean maximal postoperative pain scores were 5.83 ± 2.5 in SDPC vs 6.37 ± 2.33 in FSLT and the recurrence rates were 3.33 in SDPC vs 0 in FSLT. None of the patients in the two groups experienced liquid and solid fecal incontinence and lifestyle alteration postoperatively. The Wexner score after treatment of intersphincter fistulae were 0.17 ± 0.41 in SDPC vs 0.40 ± 0.89 in FSLT and trans-sphincter fistulae were 0.13 ± 0.45 in SDPC vs 0.56 ± 1.35 in FSLT. The maximal squeeze pressure and resting pressure declined after treatment in both groups. The maximal anal squeeze pressures after treatment were reduced (23.17 ± 3.73 Kpa in SDPC vs 22.74 ± 4.47 Kpa in FSLT) and so did the resting pressures (12.36 ± 2.15 Kpa in SDPC vs 11.71 ± 1.87 Kpa in FSLT), but there were neither significant differences between the two groups and nor significant differences before or after treatment.
CONCLUSION: Traditional Chinese surgical treatment SDPC for anal fistulae with secondary tracks and abscess is safe, effective and less invasive.
PMCID: PMC3484338  PMID: 23155310
Traditional Chinese surgical treatment; Suture dragging; Pad compression; Anal fistulae; Secondary tracks and abscess
16.  Adipose-tissue-derived Stem Cells Enhance the Healing of Ischemic Colonic Anastomoses: An Experimental Study in Rats 
This experimental study verified the effect of adipose-tissue-derived stem cells (ASCs) on the healing of ischemic colonic anastomoses in rats.
ASCs were isolated from the subcutaneous fat tissue of rats and identified as mesenchymal stem cells by identification of different potentials. An animal model of colonic ischemic anastomosis was induced by modifying Nagahata's method. Sixty male Sprague-Dawley rats (10-week-old, 370 ± 50 g) were divided into two groups (n = 30 each): a control group in which the anastomosis was sutured in a single layer with 6-0 polypropylene without any treatment and an ASCtreated group (ASC group) in which the anastomosis was sutured as in the control group, but then ASCs were locally transplanted into the bowel wall around the anastomosis. The rats were sacrificed on postoperative day 7. Healing of the anastomoses was assessed by measuring loss of body weight, wound infection, anastomotic leakage, mortality, adhesion formation, ileus, anastomotic stricture, anastomotic bursting pressure, histopathological features, and microvascular density.
No differences in wound infection, anastomotic leakage, or mortality between the two groups were observed. The ASC group had significantly more favorable anastomotic healing, including less body weight lost, less ileus, and fewer ulcers and strictures, than the control group. ASCs augmented bursting pressure and collagen deposition. The histopathological features were significantly more favorable in the ASC group, and microvascular density was significantly higher than it was in the control group.
Locally-transplanted ASCs enhanced healing of ischemic colonic anastomoses by increasing angiogenesis. ASCs could be a novel strategy for accelerating healing of colonic ischemic risk anastomoses.
PMCID: PMC3398108  PMID: 22816056
Colonic anastomosis; Ischemia; Anastomotic healing; Adipose-tissue-derived stem cell; Angiogenesis
Cardiovascular Diseases  1977;4(1):61-68.
Polybutilate coated polyester (Dacron) sutures were evaluated in a variety of cardiovascular procedures performed on 117 patients. The age range was from 6 months to 88 years, and long-term follow-up was available in 100 patients. The most frequently sutured tissues were those of the aorta, atrium, fascia and pericardium. Suture sizes ranged from 1-0 through 5-0, the most common being 3-0. There were no suture related complications, and the performance was found to be superior to non-coated polyester sutures and other forms of coated sutures. Favorable characteristics were: 1) ease of passage through tissue, especially through prosthetic materials; 2) ease of tying, 3) increased knot security; and 4) better handling characteristics in general. Because of the firm bonding of polybutilate with the polyester suture, flaking (minute amounts of the coating which become dislodged) and suture drag characteristics of other coated polyester sutures were not experienced.
PMCID: PMC287638  PMID: 15216135
18.  Laparoscopic closure of small bowel perforation: Technique of small bowel anchoring to the abdominal wall 
More and more complicated laparoscopic abdominal surgeries are now being performed across the world. Laparoscopic suturing of the bowel perforations is being performed by experienced surgeons. We have developed our own technique of small bowel anchoring to the abdominal wall before suturing the perforation.
A single stitch is taken at the corner of the perforation. The long end of the suture is retrieved by a suture retrieval needle and the small bowel is anchored to the abdominal wall. Rest of the bowel perforation is suture by the intracorporeal knot-tying technique.
Anchoring the bowel to the abdominal wall helps in fixation of the bowel to be sutured. This helps specifically for large perforation. Suturing and knot tying is relatively easy by this technique.
PMCID: PMC2734901  PMID: 19727380
Bowel anchoring; laparoscopy; small bowel perforation
19.  Achilles tendon suture deteriorates tendon capillary blood flow with sustained tissue oxygen saturation – an animal study 
Treatment of ruptured Achilles tendons currently constitutes of conservative early functional treatment or surgical treatment either by open or minimal invasive techniques. We hypothesize that an experimental Achilles tendon suture in an animal model significantly deteriorates Achilles tendon microcirculation immediately following suturing.
Fifteen Achilles tendons of eight male Wistar rats (275–325 g) were included. After preparation of the Achilles tendon with a medial paratendinous approach, Achilles tendon microcirculation was assessed using combined Laser-Doppler and spectrophotometry (Oxygen-to-see) regarding:
- tendinous capillary blood flow [arbitrary units AU]
- tendinous tissue oxygen saturation [%]
- tendinous venous filling pressure [rAU]
The main body of the Achilles tendon was measured in the center of the suture with 50 Hz. 10 minutes after Achilles tendon suture (6-0 Prolene), a second assessment of microcirculatory parameters was performed.
Achilles tendon capillary blood flow decreased by 57% following the suture (70 ± 30 AU vs. 31 ± 16 AU; p < 0.001). Tendinous tissue oxygen saturation remained at the same level before and after suture (78 ± 17% vs. 77 ± 22%; p = 0.904). Tendinous venous filling pressure increased by 33% (54 ± 16 AU vs. 72 ± 20 AU; p = 0.019) after suture.
Achilles tendon suture in anaesthetised rats causes an acute loss of capillary perfusion and increases postcapillary venous filling pressures indicating venous stasis. The primary hypothesis of this study was confirmed. In contrast, tendinous tissue oxygen saturation remains unchanged excluding acute intratendinous hypoxia within the first 10 minutes after suture. Further changes of oxygen saturation remain unclear. Furthermore, it remains to be determined to what extent reduced capillary blood flow as well as increased postcapillary stasis might influence tendon healing from a microcirculatory point of view in this animal setting.
PMCID: PMC2731078  PMID: 19674439
20.  Modeling of Needle-Tissue Interaction Forces During Surgical Suturing 
This paper presents a model of needle tissue interaction forces that a rigid suture needle experiences during surgical suturing. The needle-tissue interaction forces are modeled as the sum of lumped parameters. The model has three main components; friction, tissue compression, and cutting forces. The tissue compression force uses the area that the needle sweeps out during a suture to estimate both the force magnitude and force direction. The area that the needle sweeps out is a direct result of driving the needle in a way that does not follow the natural curve of the needle. The friction force is approximated as a static friction force along the shaft of the needle. The cutting force acts only on the needle tip. The resulting force and torque model is experimentally validated using a tissue phantom. These results indicate that the proposed lumped parameter model is capable of accurately modeling the forces experienced during a suture.
PMCID: PMC3966136
21.  Task-specific bench model training versus basic laparoscopic skills training for laparoscopic radical prostatectomy: a randomized controlled study 
Performing a laparoscopic urethrovesical anastomosis (LUA) after a radical prostatectomy is technically challenging for the novice laparoscopic surgeon. We developed a low-fidelity urethrovesical model (UVM) to allow a urologist to practise this critical step. The aim of our study was to compare the effect of task-specific bench model training (anastomotic suturing on the UVM) with that of basic laparoscopic suturing on intracorporeal urethrovesical anastomosis performance.
We recruited 28 senior surgical residents, fellows or staff surgeons for this prospective, single-blinded, randomized controlled study. We randomly assigned participants to an intervention group practising LUA on the UVM or to a control group practising basic laparoscopic suturing and knot-tying on a foam pad. After practising, we videotaped participants performing 5 intra-corporeal interrupted sutures on a foam pad and a LUA on the UVM. A blinded expert scored the videotaped performance using a laparoscopic suturing checklist (CL) and a global rating scale (GRS), and timed the performance.
On the foam pad suturing task, the group that trained on the UVM had significantly higher CL scores (10.9 v. 8.1, p = 0.017). On the LUA task, the group that trained on the UVM had significantly higher CL scores (10.9 v. 8.1, p = 0.017), GRS (29.6 v. 22.8, p = 0.005) and shorter times (27.6 v. 38.3 min, p = 0.004) than the control group.
Our task-specific bench model was shown to be superior to basic laparoscopic suturing drills on a foam pad.
PMCID: PMC2645873  PMID: 19293971
Suture materials in orthopaedic surgery are used for closure of wounds, repair of fascia, muscles, tendons, ligaments, joint capsules, and cerclage or tension band of certain fractures. The purpose of this study was to compare the biomechanical properties of eleven commonly used sutures in orthopaedic surgery. Three types of braided non-absorbable and one type of braided absorbable suture material with different calibers (n=77) underwent biomechanical testing for maximum load to failure, strain, and stiffness. All samples were tied by one surgeon with a single SMC (Seoul Medical Center) knot and three square knots. The maximum load to failure and strain were highest for #5 FiberWire and lowest for #0 Ethibond Excel (p<0.001). The stiffness was highest for #5 FiberWire and lowest for #2-0 Vicryl (p<0.001). In all samples, the failure of the suture material occurred at the knot There was no slippage of the knot in any of the samples tested. This data will assist the orthopaedic surgeon in selection and application of appropriate suture materials and calibers to specific tasks.
PMCID: PMC2958276  PMID: 21045977
23.  Repair of olecranon fractures using fiberWire without metallic implants: report of two cases 
Olecranon fractures are a common injury in fractures. The tension band technique for olecranon fractures yields good clinical outcomes; however, it is associated with significant complications. In many patients, implants irritate overlying soft tissues and cause pain. This is mostly due to protrusion of the proximal ends of the K-wires or by the twisted knots of the metal wire tension band. Below we described 2 cases of olecranon fractures treated with a unique technique using FiberWire without any metallic implants. Technically, the fragment was reduced, and two K-wires were inserted from the dorsal cortex of the distal segment to the tip of the olecranon. K-wire was exchanged for a suture retriever, and 2 strands of FiberWire were retrieved twice. Each of the two FiberWires was manually tensioned and knotted on the posterior surface of the olecranon. Bony unions could be achieved, and patients had no complaint of pain and skin irritation. There was only a small loss of flexion and extension in comparison with that of the contralateral side, and the patient did not feel inconvenienced in his daily life. Using the method described, difficulty due to K-wire or other metallic implants was avoided.
PMCID: PMC2964611  PMID: 20937160
24.  Current Approaches for Management of Postpenetrating Keratoplasty Astigmatism 
Journal of Ophthalmology  2011;2011:708736.
A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages.
PMCID: PMC3147001  PMID: 21811668
25.  Uterine Compression Sutures as an Effective Treatment for Postpartum Hemorrhage: Case Series 
AJP Reports  2011;1(1):47-52.
We evaluated the role of uterine compression sutures as a conservative treatment for postpartum hemorrhage (PPH) after failed medical treatment. We retrospectively reviewed the charts of all patients who delivered between 2003 and 2009 at a single tertiary care center and who underwent uterine compression sutures for PPH. Twelve women had uterine compression sutures for PPH. The mean age of the patients was 36.3 ± 5.2 years. The mean gestational age at delivery was 37.7 ± 2.0 weeks, and the average estimated blood loss was 2.1 ± 1.1 L. The mean procedure time to perform the uterine compression sutures was 9.3 ± 2.8 minutes. The success rate of compression sutures was 92% with only one failure resulting in a hysterectomy. Uterine compression sutures are an effective method for the treatment of PPH, thus avoiding hysterectomy and preserving potential fertility.
PMCID: PMC3653545  PMID: 23705085
Fertility; postpartum hemorrhage; uterine compression sutures

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