The anatomical knowledge is the most important and has a direct link with success of operation in cervical spine surgery. The authors measured various cervical parameters in cadaveric dry bones and compared with previous reported results.
We made 255 dry bones age from 19 to 72 years (mean, 42.3 years) that were obtained from 51 subjects in 100 subjects who donated their bodies. All measurements from C3-C7 levels were made using digital vernier calipers, standard goniometer, and self-made fix tool for two different cervical axes (canal and disc setting). We classified into 4 groups (uncinate process, vertebral body, lamina, and pedicle) and measured independently by two neurosurgeons for 28 parameters.
We analyzed 23970 measurements by mean value and standard deviations. In comparing with previous literatures, there are some different results. The mean values for uncinate process (UP) width ranged from 5.5 mm at C4 and 5 to 6.3 mm at C3 and C7 in men. Also, in women, the mean values for UP width ranged from 5.5 mm at C5 to 6.3 mm at C7. C7 was widest and C5 was most narrow than other levels. The antero-posterior length of UP tended to increase gradually from C3 to C6. The tip way, tip distance, and base distance of UP also showed increasing pattern from C3 to C7.
These measurements can provide the spinal surgeons with a starting point to address bony architectures surrounding targeted soft tissues for safeguard against unintended damages during cervical operation.
Cervical vertebra; Uncinate process; Dry bone; Parameters
The so called anterior meningeal artery (AMA) is a branch of the vertebral artery (VA), which had been interpreted as a supplying vessel of the dura in the foramen magnum and upper cervical level.
In this study, we examined the anatomy of this artery and relationships to its surrounding structures for treatment modalities. With the aid of magnification, five adult cadaveric head and neck complex and five cervical spines were examined after perfusion of the vessels with colored silicone.
The AMA arose from the VA between the C2 and C3 level, and passed medially through the intrervertebral foramen anterior to the dural sheath of the third cervical nerve root. It ran upwards dorsal to the deep layer of the posterior longitudinal ligament (PLL) with anterior internal vertebral venous plexus. Rostrally, it formed an arcade above the apex of the odontoid process with its contralateral mate.
The AMA gave off several tiny branches to the deep layer of the PLL, ligaments and soft tissues above the apex of the odontoid process, and vertebral bodies of the axis. At the level of the foramen magnum, it ended in several small twigs to the dura. Anastomoses between the AMA system and adjacent vessels were observed. One was directed through the hypoglossal canal to the ascending pharyngeal artery and the other was with the V3 segment of the VA. The origin and course of the two AMA, and anastomoses were symmetric. Although the AMA feeds the ventral dura of the foramen magnum, the perfusion area is larger than its name suggests, including the bony and ligamentous structures in the craniovertebral junction.
Anatomical knowledge of the AMA, including its anastomoses and layer relationships to the surrounding structures, may help to perform treatment modalities in this region rationally.
anatomy, anterior meningeal artery, craniovertebral junction, vertebral artery
A fundamental function of the respiratory system is the supply of oxygen to meet metabolic demand. Morphological constraints on the supply of oxygen, such as the structure of the lung, have previously been studied in birds. Recent research has shown that uncinate processes (UP) are important respiratory structures in birds, facilitating inspiratory and expiratory movements of the ribs and sternum. Uncinate process length (UPL) is important for determining the mechanical advantage for these respiratory movements. Here we report on the relationship between UPL, body size, metabolic demand and locomotor specialisation in birds. UPL was found to scale isometrically with body mass. Process length is greatest in specialist diving birds, shortest in walking birds and intermediate length in all others relative to body size. Examination of the interaction between the length of the UP and metabolic demand indicated that, relative to body size, species with high metabolic rates have corresponding elongated UP. We propose that elongated UP confer an advantage on the supply of oxygen, perhaps by improving the mechanical advantage and reducing the energetic cost of movements of the ribs and sternum.
Posterior instrumentation through the pedicle is a common surgery. Understanding the morphometry of the pedicle and the anatomy of adjacent neural structures should help decrease the risk of postoperative complications. T1–L5 segments from 15 sets of human vertebrae were separated into individual vertebrae and the morphometric characteristics of the thoracic and lumbar spine and the safe zone of the pedicle were analyzed. T11–L5 segments from six human cadavers were dissected. Measurements were taken from the pedicle to the dura and nerve roots superiorly, inferiorly, medially, and laterally, and the transverse angles of the nerve roots were measured. Pedicles were widest in L5 and narrowest in T4 in the transverse plane, and widest in T11 or T12 and narrowest in T1 in the sagittal plane. In individual pedicle, the ranges of the safe zone width and height were 3.4–7.7 and 8.6–13.7 mm, respectively, in T1–T10; and 7.2–17.8 and 13.9–16.7 mm, respectively, in T11–L5. The transverse angle of the pedicle decreases progressively from T1 to T12, then increase from L1 to L5. In sagittal angle, the largest angle localized at T2 and the smallest at L5. The mean distances from pedicles to adjacent neural structures were greater superiorly and laterally than inferiorly and medially. The lateral distance between nerve root and the pedicle ranged from 2.4 to 9.6 mm in lumbar spine. This study provides potential safe zones for the application of through-pedicle procedures to help decrease the risk of postoperative complications.
Posterior instrumentation; Morphometry; Thoracic and lumbar spine; Safe zone; Through-pedicle procedures
The uncinate fasciculus connects limbic structures, such as the hippocampus and amygdala, with frontal regions. This study utilized diffusion tensor imaging to examine the structural integrity of the uncinate fasciculus in late-life depression.
18 elderly depressed and 19 elderly nondepressed subjects were matched for age and sex; 8 subjects had mid- to late-onset of depression while 10 subjects had early-onset depression. 3T diffusion tensor imaging-based fiber tract mapping delineated the uncinate fasciculus in each hemisphere, which guided measurement of the fractional anisotropy of the uncinate fasciculus in the temporal stem. After controlling for age and sex, differences between diagnostic groups were assessed.
After controlling for age and sex, individuals with early onset depression exhibited lower anisotropy of the left uncinate fasciculus than did mid- and late-onset or nondepressed subjects (F2,36 = 4.50, p = 0.02). Analyses of the right uncinate fasciculus were not statistically significant.
This provides preliminary evidence that there is a structural connectivity deficit between left frontal and limbic structures in early-onset depression. Further work is needed to determine if this is seen in younger depressed subjects, and if it influences treatment outcomes.
depression; elderly; magnetic resonance imaging; temporal lobe
The objective of this study was to determine atlanto-axial bone morphometric measurements related to screw transarticular fixation technique. One hundred helical computerized tomography (helical CT) scans with volumetric acquisition, including the first and the second cervical vertebrae, were studied. The screw insertion axis according to the Magerl technique for C1–C2 transarticular fixation was the referential to select the correct oblique axial and oblique parasagittal planes obtained with multiplanar reconstruction (MPR) on helical CT. The selected measured parameters on each side of the vertebrae were C2 interarticular isthmus height and width, optimal screw length, optimal screw trajectory sagittal and axial angles, and the distance between the ideal screw trajectory and the vertebral artery groove. C2 interarticular isthmus height measured 7.75±1.27 mm, C2 interarticular isthmus width 7.94±1.72 mm, optimal screw length 39.03±2.81 mm, optimal screw trajectory sagittal angle 57.54±5.28°, optimal screw trajectory medial angle 7.90±4.05°. Isthmus narrowing under 5 mm (height and/or width) was seen in 5% of cases. In 30% of cases reconstructed parasagittal images showed the vertebral artery groove. In those cases, the distance between the vertebral artery groove and the ideal screw path was measured. This distance measured under 2.5 mm in 7% of C2 articular masses. A classification of C2 articular mass morfology was proposed. The C2 articular masses without anatomic variations predisposing to vertebral artery injury were considered type I. The C2 articular masses potentially associated with vascular injury (12%) were classified as type II. Potential risk was identified at the C2 isthmus only (3%), at the anterior portion of C2 articular mass only (7%) or at both regions (2%). According to selected criteria 18% of patients would have at least one side C2 articular mass with potential risk for the vertebral artery. In 6% of patients the potential risk was identified bilaterally. There is a great variation in the maximum and minimum values of the anatomic measurements. Therefore preoperative CT scans are very important to identify type II cases, such that the surgeon may preoperatively define the bony anatomy trough which the screws will pass.
Atlanto-axial joint; Arthrodesis; Helical computed tomography; Uupper cervical spine
The purpose of this study was to measure the structures of the ventral of lateral masses using cadaver specimens and to quantitatively compare the safety zone for the two major techniques used on each vertebral level from C3 to C6.
This study is based on 52 cervical vertebrae of 13 cadavers. The anatomical measurements focused on the anterior surface of the lateral mass. We investigated the safety width, heights, and the height of nerve roots.
The mean values of the safety width of the Magerl technique from C3 to C6 were 6.1, 7.3, 6.4 and 4.3 mm, respectively. The mean values of the safety width of the Roy-Camille technique were 6.7, 6.6, 5.8 and 5.4 mm, respectively. The mean values of the safety height of the Magerl technique were 5.0, 5.4, 5.8 and 5.2 mm, respectively. The mean values of the safety height of the Roy-Camille technique were 4.9, 4.0, 1.0 and −1.2 mm, respectively. The mean values of the nerve root height were 3.9, 4.9, 5.9 and 6.9 mm, respectively.
The safety width of the Magerl technique was shorter at C6 because the vertebral artery runs more laterally at C6. The height for the Magerl technique was not significantly different from C3 to C6, however, the safety height for the Roy-Camille technique was significantly shorter at C5 and C6. Our findings suggest that it is important to ensure that the screw(s) penetrate through the cranial side of the ventral aspect of a lateral mass when performing the Magerl technique at all vertebral levels, and to carefully select the screw length when using the Roy-Camille technique, especially at C5 and C6, in order to avoid nerve root injury.
Anatomy; Cervical foramen; Lateral mass screw
Morphometric data on dorsal cervical anatomy were examined in an effort to protect the nerve root near the lateral mass during posterior foraminotomy.
Using 25 adult formalin-fixed cadaveric cervical spines, measurements were taken at the lateral mass from C3 to C7 via a total laminectomy and a medial one-half facetectomy. The morphometric relationship between the nerve roots and structures of the lateral mass was investigated. Results from both genders were compared.
Following the total laminectomy, from C3 to C7, the mean of the vertical distance from the medial point of the facet (MPF) of the lateral mass to the axilla of the root origin was 3.2-4.7 mm. The whole length of the exposed root had a mean of 4.2-5.8 mm. Following a medial one-half facetectomy, from C3 to C7, the mean of the vertical distance to the axilla of the root origin was 2.1-3.4 mm, based on the MPF. Mean vertical distances from the MPF to the medial point of the root that crossed the inferior margin of the intervertebral disc were 1.2-2.7 mm. The mean distance of the exposed root was 8.2-9.0 mm, and the mean angle between the dura and the nerve root was significantly different between males and females, at 53.4-68.4°.
These data will aid in reducing root injuries during posterior cervical foraminotomy.
Posterior foraminotomy; Spinal nerve roots; Laminectomy; Facetectomy; Cadaveric study
In 1868 Thomas Huxley first proposed that dinosaurs were the direct ancestors of birds and subsequent analyses have identified a suite of ‘avian’ characteristics in theropod dinosaurs. Ossified uncinate processes are found in most species of extant birds and also occur in extinct non-avian maniraptoran dinosaurs. Their presence in these dinosaurs represents another morphological character linking them to Aves, and further supports the presence of an avian-like air-sac respiratory system in theropod dinosaurs, prior to the evolution of flight. Here we report a phylogenetic analysis of the presence of uncinate processes in Aves and non-avian maniraptoran dinosaurs indicating that these were homologous structures. Furthermore, recent work on Canada geese has demonstrated that uncinate processes are integral to the mechanics of avian ventilation, facilitating both inspiration and expiration. In extant birds, uncinate processes function to increase the mechanical advantage for movements of the ribs and sternum during respiration. Our study presents a mechanism whereby uncinate processes, in conjunction with lateral and ventral movements of the sternum and gastral basket, affected avian-like breathing mechanics in extinct non-avian maniraptoran dinosaurs.
Aves; theropod; uncinate processes; ventilation; gastralia
Although several clinical applications of transpedicular screw fixation in the lumbar spine have been documented for many years, few anatomic studies concerning the lumbar pedicle and adjacent neural structures have been published. The lumbar pedicle and its relationships to adjacent neural structures were investigated through an anatomic study. Our objective is to highlight important considerations in performing transpedicular screw fixation in the lumbar spine. Twenty cadavers were used for observation of the lumbar pedicle and its relations. After removal of whole posterior bony elements including spinous processes, laminae, lateral masses, and inferior and superior facets, the isthmus of the pedicle was exposed. Pedicle width and height (PW and PH), interpedicular distance (IPD), pedicle-inferior nerve root distance (PIRD), pedicle-superior nerve root distance (PSRD), pedicle-dural sac distance (PDSD), root exit angle (REA), and nerve root diameter (NRD) were measured. The results indicated that the average distance from the lumbar pedicle to the adjacent nerve roots superiorly, inferiorly and to the dural sac medially at all levels ranged from 2.9 to 6.2 mm, 0.8 to 2.8 mm, and 0.9 to 2.1 mm, respectively. The mean PH and PW at L1–L5 ranged from 10.4 to 18.2 mm and 5.9 to 23.8 mm, respectively. The IPD gradually increased from L1 to L5. The mean REA increased consistently from 35° to 39°. The NRD was between 3.3 and 3.9 mm. Levels of significance were shown for the P<0.05 and P<0.01 levels. On the basis of this study, we can say that improper placement of the pedicle screw medially and inferiorly should be avoided.
Anatomy Cadaver Lumbar pedicle Transpedicular fixation
Endonasal dacryocystorhinostomy (DCR) has been widely used to treat nasolacrimal duct obstruction. Here, we evaluated the anatomical advantages of the uncinate process as a landmark and to study the effect of unciformectomy on success rate and complications of endonasal DCR .
In total, 288 eyes of 265 adult patients who underwent endonasal DCR between January 2003 and February 2010 were reviewed retrospectively. The eyes were classified into two groups, according to whether unciformectomy was performed or not. All surgical procedures and surgical indications were the same except unciformectomy and endonasal DCR was performed by one surgeon. Unciformectomy was performed by resecting the anterior part of uncinate process.
One hundred and eighty-six eyes of 168 patients received endonasal DCR with unciformectomy, and 102 eyes of 97 patients received endonasal DCR alone. The average success rate of endonasal DCR with unciformectomy was 97.8 % and that of endonasal DCR alone was 90.2 %, with statistically significant difference (Student's t-test, p-value < 0.05). There were 14 eyes with post-operative nasolacrimal obstruction, caused by granuloma in five eyes, intranasal synechia in two eyes, membranous obstruction in six eyes, and canalicular stenosis in one eye. There were no serious complications such as orbital fat prolapse, cerebrospinal fluid leak, or delayed hemorrhage.
Anterior resection of the uncinate process gives improved access to the lacrimal bone by exposing the medial aspect of the lacrimal fossa and forming the precise location of the osteotomy on the lacrimal bone during endonasal DCR. Thus, the uncinate process can be used as an anatomical landmark for endonasal DCR. The unciformian endonasal DCR improves operation success rate by allowing access to the large space of the nasal cavity and reducing the synechiae of the nasal cavity.
Endonasal dacryocystorhinostomy; Nasolacrimal duct obstruction; Postoperative complications; Success rate; Uncinate process
Total disc replacement (TDR) is expected to provide a more physiologic alternative to fusion. However, long-term clinical data proving the efficacy of the implants is lacking. Limited clinical data suggest somewhat of a disagreement between the in vitro biomechanical studies and in vivo assessments. This conceptual paper presents the potential biomechanical challenges affecting the TDR that should be addressed with a hope to improve the clinical outcomes and our understanding of the devices. Appropriate literature and our own research findings comparing the biomechanics of different disc designs are presented to highlight the need for additional investigations. The biomechanical effects of various surgical procedures are analyzed, reiterating the importance of parameters like preserving uncinate processes, disc placement and its orientation within the cervical spine. Moreover, the need for a 360° dynamic system for disc recipients who may experience whiplash injuries is explored. Probabilistic studies as performed already in the lumbar spine may explore high risk combinations of different parameters and explain the differences between “standard” biomechanical investigations and clinical studies. Development of a patient specific optimized finite element model that takes muscle forces into consideration may help resolve the discrepancies between biomechanics of TDR and the clinical studies. Factors affecting long-term performance such as bone remodeling, subsidence, and wear are elaborated. In vivo assessment of segmental spine motion has been, and continues to be, a challenge. In general, clinical studies while reporting the data have placed lesser emphasis on kinematics following intervertebral disc replacements. Evaluation of in vivo kinematics following TDR to analyze the quality and quantity of motion using stereoradiogrammetric technique may be needed.
Biomechanics; Total disc replacement; Finite element technique; Kinematics; Patient specific biomechanical models
The formation of the maxillary sinus (MS) is tied to the maturation of the craniofacial bones during development. The MS and surrounding bone matrices in Japanese foetal specimens were inspected using cone beam computed tomography relative to the nasal cavity (NC) and the surrounding bones, including the palatine bone, maxillary process, inferior nasal concha and lacrimal bone. The human foetuses analysed were 223.2 ± 25.9 mm in crown-rump length (CRL) and ranged in estimated age from 20 to 30 weeks of gestation. The amount of bone in the maxilla surrounding the MS increased gradually between 20 and 30 weeks of gestation. Various calcified structures that formed the bone matrix were found in the cortical bone of the maxilla, and these calcified structures specifically surrounded the deciduous tooth germs. By 30 weeks of gestation, the uncinate process of the ethmoid bone formed a border with the maxilla. The distance from the midline to the maximum lateral surface border of the MS combined with the width from the midline to the maximum lateral surface border of the inferior nasal concha showed a high positive correlation with CRL in Japanese foetuses. There appears to be a complex correlation between the MS and NC formation during development in the Japanese foetus. Examination of the surrounding bone indicated that MS formation influences maturation of the maxilla and the uncinate process of the ethmoid bone during craniofacial bone development.
Cone beam CT; Maxillary sinus; Inferior nasal concha; Deciduous tooth; Development
Neuroimaging studies in late life depression have reported decreased structural integrity of white matter tracts in the prefrontal cortex. Functional studies have identified changes in functional connectivity among several key areas involved in mood regulation. Few studies have combined structural and functional imaging. In this study we sought to examine the relationship between the uncinate fasciculus, a key fronto-temporal tract and resting state functional connectivity between the ventral prefrontal cortex ((PFC) and limbic and striatal areas.
The sample consisted of 24 older patients remitted from unipolar major depression. Each participant had a magnetic resonance imaging brain scan using standardized protocols to obtain both diffusion tensor imaging and resting state functional connectivity data. Our statistical approach compared structural integrity of the uncinate fasciculus and functional connectivity data.
We found positive correlations between left uncinate fasciculus (UF) fractional anisotropy (FA) and resting state functional connectivity (rsFC) between the left ventrolateral PFC and left amygdala and between the left ventrolateral PFC and the left hippocampus. In addition, we found a significant negative correlation between left ventromedial PFC-caudate rsFC and left UF FA. The right UF FA did not correlate with any of the seed region based connectivity.
These results support the notion that resting state functional connectivity reflects structural integrity, since the ventral PFC is structurally connected to temporal regions by the UF. Future studies should include larger samples of patients and healthy comparison subjects in which both resting state and task-based functional connectivity are examined.
Stellate ganglion block (SGB) is very effective in management of chronic regional pain syndrome (CRPS-1). However, serious complication may occur due to accidental intravascular (intra-arterial) injection of local anaesthetic agents. Abdi and others, has suggested a modified technique in which fluoroscopy-guided block is given at the junction of uncinate process and body of vertebra at C7 level. In this approach vascular structures remain away from the trajectory of needle and thus avoid accidental vascular injection. We have used this technique of SGB in nine patients who were treated for CRPS-I. The blocks were effective in all the patients all the time without any vascular or other serious complication.
CRPS-I; modified technique; stellate ganglion block
Anatomical study of the relationship among the cervical nerve roots, intervertebral disc, and lateral mass is important for the neurosurgeon to avoid complications of posterior cervical foraminotomy.
Six adult cadavers were studied. The muscles of the back of the neck were removed to expose the cervical vertebrae posteriorly from C3 to C7. We measured the length, height, extent, and angulations of the nerve roots from the medial point of the facet (MPF) after a total laminectomy, then after one-half facetectomy. The height, width, anteroposterior diameter of the lateral mass, then the height and anteroposterior diameter of the neural foramen were also measured.
After total laminectomy from C3 to C7, all measures were taken from MPF showed that the mean length of the exposed root was 6.5–8.8 mm while vertical distance was 4–5.4 mm and the horizontal distance was 5.1–7.1 mm. Following a medial one-half facetectomy; the mean length of the exposed root was 8.9–12.3 mm, the vertical distance was 5.5–7.3 mm while the horizontal distance was 7.1–9.8 mm. The mean angulations of the nerve roots were 50.9–53.3º. There was a significant difference after total laminectomy and medial one-half facetectomy.
Anatomic and morphologic study of the cervical nerve roots and their relationships to the lateral mass and the intervertebral disc are useful landmarks to reduce the operative complications of the posterior foraminotomy.
Posterior cervical foraminotomy; Cervical laminoforaminotomy; Cervical nerve root anatomy
To investigate the morphometric characteristics of the pituitary gland and diaphragma sellae in Korean adults.
Using the 33 formaline fixed adult cadavers (23 male, 10 female), the measurements were taken at the diaphragma sellae and pituitary gland. The authors investigated the relationship between dura and structures surrounding pituitary gland, morphometric aspects of pituitary gland and stalk, and morphometric aspect of central opening of diaphragma sellae.
The boundary between the lateral surface of pituitary gland and the medial wall of cavernous sinus was formed by the thin dural layer and pituitary capsule. The pituitary capsule adherent tightly to the pituitary gland was observed to continue from the diaphragma sellae. Mean width, length, and height of the pituitary gland were 14.3 ± 2.1, 7.9 ± 1.3, and 6.0 ± 0.9 mm in anterior lobes, and 8.7 ± 1.7, 2.9 ± 1.1, and 5.8 ± 1.0 mm in posterior lobes, respectively. Although all dimensions of anterior lobe in female were slightly larger than those in male, statistical significance was noted in only longitudinal dimension. The ratio of posterior lobe to the whole length of pituitary gland was about 27%. The mean thickness of pituitary stalk was 2 mm. The diaphragmal opening was 5 mm or more in 26 (78.8%) of 33 specimen. The opening was round in 60.6% of the specimen, and elliptical oriented in an anterior-posterior or transverse direction in 39.4%.
These results provide the safe anatomical knowledge during the transsphenoidal surgery and may be helpful to access the possibility of the development of empty sella syndrome.
Pituitary gland; Diaphragma sellae; Cadaver
Variations in the bony components of the nose are often
encountered. One such variation was found in a 49-year-old male
who had undergone conventional external dacryocystorhinostomy
for adult onset nasolacrimal duct blockage. Intraoperatively, a
thick bar of bone was seen beneath and parallel to the lacrimal
sac fossa after a complete osteotomy had been made. Another
osteotomy had to be fashioned in this bone to reach the nasal
cavity. Postoperative 3D computed tomographic scan revealed
the bone to be an anatomical variation of the uncinate process
of the ethmoidal bone which was rather anteriorly placed, much
thicker than usual, and attached to the nasal roof.
The uncinate process is thin, curved and its anterior edge may
frequently overlap some part of the lacrimal fossa. However, to
our knowledge, the presence of such a large and thick uncinate
process necessitating an additional large osteotomy has not been
Dacryocystorhinostomy; nasal bones; uncinate process
Objectives: To reveal the variations of the iliolumbar artery and the iliolumabar veins and their correlation with the surrounding important structures.
Methods: We dissected the iliolumbar region bilaterally in 20 formalin-fixed adult cadavers. The diameter of the iliolumbar artery at its origin, its length up to the branching point, the distance between the iliolumbar artery and the inferior margin of the fifth lumbar vertebra and the distance between the iliolumbar artery and the bifurcation point of the common iliac artery, were measured. The pattern of drainage, the dimensions, the points of confluence with the common iliac vein and the obliquity of the iliolumbar vein were noted. The correlation between the iliolumbar artery and the veins to the obturator nerve and the lumbosacral trunk was recorded.
Results: The iliolumbar artery originated from the posterior trunk of the internal iliac artery or from the internal iliac artery. The mean diameter of the iliolumbar artery, at its origin, was 3.5±0.5 mm. The mean distance between the origin of the iliolumbar artery and the bifurcation point to the iliac and the lumbar branches was 12.2±5.5 mm. The distance between the origin of the iliolumbar artery and the lower edge of the fifth lumbar vertebra was 43.2±11.6 mm. The distance between the origin of the iliolumbar artery and the bifurcation point of the common iliac artery was 38.7±10.6 mm.
The mean distance of the iliolumbar veins from the inferior vena cava, overall, was 35± 9.9 mm. The mean width of the mouth of the iliolumbar vein was10.7 ± 5.1 mm and the mean angle of obliquity of the vein with respect to the long axis of the common iliac vein was 75.50. The tributaries which drained into the main iliolumbar vein were variable.
The iliolumbar artery passed anterior in 70% and it passed posterior to the obturator nerve in 30%. The veins were lying anterior to the obturator nerve in 45% and they were lying posterior in 55%. The multiple tributaries which drained into the iliolumbar vein relation of the tributaries were variable, few passed anterior and few passed posterior.
The iliolumbar artery was seen anterior to the lumbosacral trunk in 30%, it was posterior in 54%, it was cleaved in 8% and the branches of the artery were passing on either side of the lumbosacral trunk to enclose it like a clasp in 8%. The veins were anterior to the lumbosacral trunk in 40% and they were posterior in 60%.
Conclusion: The anatomical features of the iliolumbar artery, the iliolumbar veins and their correlation with the anatomical landmarks, which were presented here, would be helpful in decreasing the iatrogenic trauma to the neurovascular structures in the iliolumbar region.
Iliolumbar artery; Iliolumbar veins; Obturator nerve; Lumbosacral trunk; Injury; Spine surgery
The transoral approaches have become commonplace in modern neurosurgical practice for treatment of ventral midline lesions of the clivus and upper cervical spine. Although the standard technique of transoral surgery is conceptually simple, anatomic relationships are not so readily appreciated. The present study was undertaken in an effort to define more clearly the midline anatomic relationships as they pertain to the standard transoral and transpalatine operations. The anatomic relationships involved in planning microsurgical transoral approaches were examined in 15 human cadavers. Landmarks approximating the midline of the skull base and the upper cervical spinal canal were defined to assist the surgeon's orientation. Measurements were made in axial, sagital, and parasagittal planes to various neurovascular structures in the posterior cranial fossa and upper cervical spinal canal. The study revealed that, for the standard transoral and transoral-transpalatine dissections, the carotid arteries, abducens nerves, interior petrosal sinuses, hypoglossal nerves, and vertebral arteries would be a greatest risk being 0.76, 1.06, 1.51, 1.34, and 1.52 cm from the midline at specified locations. The measurements and the computed tomography images provide a useful reference for the surgeon.
A basic step of Functional Endoscopic sinus surgery—the most modern and revolutionary surgical treatment for chronic and recurring sinusitis, is removal of uncinate process to expose the infundibulum. The purpose of this study is to explore the functional role of uncinate process with special reference to endoscopic sinus surgery.
A fixed dose of sterile methylene blue was sprayed into the nasal cavities of post endoscopic sinus surgery cases, 20 without uncinate process preservation and 20 with uncinate process preservation. The area of staining/deposition of the stain in the ethmoidal cavity and the maxillary sinuses was endoscopically observed.
Deposition of methylene blue was consistently found to be occurring in a larger area of the ethmoidal cavity including the maxillary sinus in post endoscopic sinus surgery cases without uncinate process preservation.
Uncinate proces probably acts as a protective wall by directing the allergen bearing and contuminated inspired air away from the sinuses and facilitating ventilation of the sinuses in the mucocilliary pretreated expiratory phase. Injudictious removal of the uncinate process especially in cases with allergic rhinosinusitis should thus expose the sinus mucosa to contaminated air.
Uncinate process; Endoscopic sinus surgery
Introduction The cervical spine is a highly mobile segment of the spinal column, liable to a variety of diseases and susceptible to trauma. It is a complex region where many vital structures lie in close proximity. Lateral mass screw fixation has become the method of choice in stabilizing subaxial cervical spine among other posterior cervical fixation techniques whenever the posterior elements are absent or compromised.
Objective This study examined cervical specimens of cadavers and cervical computed tomography (CT) scans to minimize as much as possible complications of cervical lateral mass screw placement such as vertebral artery or nerve root injuries, facet joint violations, or inadequate placement.
Methods Forty normal cervical CT scans, obtained from the emergency unit as part of the trauma workup, were included in this study plus 10 cervical cadaveric specimens obtained from the Alexandria Neuro-anatomy laboratory. There were three fixed parameters for screw insertion in this study. First, the point of screw insertion was the midpoint of the lateral mass; it was the crossing point between the sagittal and axial planes of the posterior cortex of the lateral mass. Second, the direction of the screw in the craniocaudal plane was 30 degrees cranially to avoid facet joint penetration. Third, the exit point of the screw was located on the ventral cortex of the lateral mass just lateral to the root of the transverse process in the midaxial cut of each lateral mass, to make a sound bicortical fixation without injuring the vertebral artery or the nerve root. The selected screw trajectory in this study was the line drawn between the inlet and exit points. The depth and width of the lateral mass of the cervical vertebrae from C3 to C7 were measured as well as the angle of screw trajectory from the sagittal plane. All these measures were applied on the cadaveric specimens to make sure that no injury to the vertebral artery, nerve root, or facet joint occurred.
Results As regards the collected measurements of the lateral mass of all subaxial cervical vertebrae, the study revealed that the average depth of the lateral mass was 12.83 ± 1.28 mm. The average width of the lateral mass was 11.92 ± 0.96 mm. The average divergent angle of bicortical screw insertion without injury to the vertebral artery or the nerve root was 19.51 ± 1.83 degrees. As regard the cadaveric specimens, based on all the collected measurements taken from the CT scans, there was no reported injury to the vertebral arteries or nerve roots or penetration to the facet joints.
Conclusion Lateral mass fixation can be applied easily and safely for all levels of subaxial cervical spine from C3 to C6 with the following parameters: (1) the point of entry is the midpoint of the lateral mass; (2) the screw trajectory is directed 30 degrees cranially and 20 degrees laterally; (3) the screw length is 13 to 15 mm.
lateral mass fixation; vertebral artery; nerve root; facet joint
A cadaveric study was performed to investigate the relationship between disc degeneration and morphological changes in the intervertebral foramen of cervical spine, including the effect on the nerve root. Seven fresh frozen human cadavers were dissected from C1 to T1, preserving the ligaments, capsules, intervertebral disc and the neural structures. The specimens were scanned with MRI and then scanned through CT scan in the upright position. Direct mid-sagittal and 45 degree oblique images were obtained to measure the dimension of the intervertebral disc height, foraminal height, width, area and segmental angles. Disc degeneration was inversely correlated with disc height. There was a significant correlation between disc degeneration and foraminal width (p<0.005) and foraminal area (p<0.05), but not with foraminal height. Disc height was correlated with foraminal width but not with height. The segmental angles were decreased more in advanced degenerated discs. There was a correlation between nerve root compression and decreased foraminal width and area (p<0.005). This information and critical dimensions of the intervertebral foramen for nerve root compression should help in the diagnosis of foraminal stenosis of the cervical spine in patients presenting with cervical spondylosis and radiculopathy.
Cervical Vertebrae; Intervertebral Disk; Magnetic Resonance Imaging; Tomography, X-Ray Computed
Lateral mass (LM) screws are commonly used in posterior instrumentation of the cervical spine because of their perceived safety over pedicle screws. A possible complication of cervical LM screw placement is vertebral artery injury or impingement. Several screw trajectories have been described to overcome the risks of neurovascular injury; however, each of these techniques relies on the surgeon’s visual estimation of the trajectory angle. As the reliability hereof is poorly investigated, alignment with a constant anatomical reference plane, such as the cervical lamina, may be advantageous. The aim of this investigation was to determine whether alignment of the LM screw trajectory parallel to the ipsilateral cervical lamina reliably avoids vertebral artery violation in the sub-axial cervical spine. 80 digital cervical spine CT were analysed (40 female, 40 male). Exclusion criteria were severe degeneration, malformations, tumour, vertebral body fractures and an age of less than 18 or greater than 80 years. Mean age of all subjects was 39.5 years (range 18–78); 399 subaxial cervical vertebrae (C3–C7) were included in the study. Measurements were performed on the axial CT view of C3–C7. A virtual screw trajectory with parallel alignment to the ipsilateral lamina was placed through the LM. Potential violation of the transverse foramen was assessed and the LM width available for screw purchase measured. There was no virtual violation of the vertebral artery of C3–C7 with lamina-guided LM screw placement. LM width available for screw purchase using this technique ranged from 5.2 to 7.4 mm. The sub-axial cervical lamina is a safe reference plane for LM screw placement. LM screws placed parallel to the ipsilateral lamina find sufficient LM width and are highly unlikely to injure the vertebral artery, even in bi-cortical placement. Placing LM screws parallel to the lamina appears favourable over conventional techniques.
Lateral mass screw trajectory; Surgical technique; Subaxial cervical spine; Vertebral artery injury; Cervical spine anatomy
Portal annular pancreas (PAP) is a rare variant in which the uncinate process of the pancreas extends to the dorsal surface of the pancreas body and surrounds the portal vein or superior mesenteric vein. Upon pancreaticoduodenectomy (PD), when the pancreas is cut at the neck, two cut surfaces are created. Thus, the cut surface of the pancreas becomes larger than usual and the dorsal cut surface is behind the portal vein, therefore pancreatic fistula after PD has been reported frequently. We planned subtotal stomach-preserving PD in a 45-year-old woman with underlying insulinoma of the pancreas head. When the pancreas head was dissected, the uncinate process was extended and fused to the dorsal surface of the pancreas body. Additional resection of the pancreas body 1 cm distal to the pancreas tail to the left side of the original resection line was performed. The new cut surface became one and pancreaticojejunostomy was performed as usual. No postoperative complications such as pancreatic fistula occurred. Additional resection of the pancreas body may be a standardized procedure in patients with PAP in cases of pancreas cut surface reconstruction.
Portal annular pancreas; Pancreaticoduodenectomy; Pancreas fistula