The anterolateral incision for pilon fracture surgery: an anatomic study of cutaneous blood supply.

The purpose of this study was to examine the blood supply to the adjacent skin and its vulnerability to anterolateral tibial plating performed with fibular plating through a single surgical incision. Ten lightly embalmed cadaver legs without a history of lower extremity trauma or surgery with a mean age of 71 years (range, 57 to 87 years) were used for this investigation. Each specimen was injected with a commercially available silicone compound through the popliteal artery. The left leg was plated through a modified extensile Böhler approach and the right leg served as the control. Each leg was anatomically dissected. All measurements were taken using a digital caliper by a single investigator. A mean of 93 (range, 4 to 17) perforating arteries were present and in the proximity of the fibula plate. Our findings suggest the potential for iatrogenic soft tissue breakdown along the posterior border of the anterolateral surgical incision in this procedure as a result of compromised blood supply to the skin.

Trigeminal nucleus caudalis anatomy: guidance for radiofrequency dorsal root entry zone lesioning.

OBJECT: This study seeks to improve the accuracy of trigeminal nucleus caudalis dorsal root entry zone (DREZ) radiofrequency lesioning by quantifying the size and orientation of the nucleus caudalis. METHODS: Using serial axial photographs of 6 formalin-fixed cadaver brainstems, digital nucleus caudalis measurements were taken at 1-mm intervals from the level of the obex to the C(2) dorsal nerve roots. RESULTS: From the obex to the C(2) dorsal nerve roots, the nucleus caudalis decreases in width (from 2.6 ± 0.2 to 1.0 ± 0.3 mm) and, excluding superficial tract thickness, decreases in axial nucleus depth (from 2.4 ± 0.3 to 1.7 ± 0.2 mm). At levels between the obex and 10 mm caudal to the obex, the accessory nerve rootlets exit the brainstem at the junction of the spinal trigeminal tract and the dorsal spinocerebellar tract. CONCLUSION: This study details the anatomic dimensions and orientation of the nucleus caudalis for surgeons who perform DREZ lesioning.

Anatomy and vascularization of the flexor hallucis longus muscle and its implication in free fibula flap transfer: an anatomical study.

Contracture as well as weakness of the flexor hallucis longus (FHL) are possible complications following free fibula flap harvest. Possible causes have been related to fibrotic change of the muscle either due to devascularization or compartment-like syndrome after a tight wound closure. This study elucidates the vascularization and nerve supply of the FHL muscle after fibula flap harvest in a fresh cadaver model.A fibula bone flap was harvested through a lateral approach in 20 fresh limbs. The popliteal artery was isolated and injected with a silicone compound, the muscle isolated, and its neurovascular supply visualized.The distal third and fourth portion of the FHL muscle was always found to be located in a more compressed and deeper compartment. The peroneal artery was entirely filled by the silicone compound in 17 fresh cadaver limbs with at least one branch supplying the distal fourth of the FHL. The posterior tibialis artery was filled in all limbs and an average of 2 branches was found to supply the muscle. In all dissections, the nerve supplying the FHL originated from the tibialis nerve with an average of three branches perforating the muscle.Following fibula harvest, the FHL muscle will maintain vascular supply through the distal portion of the peroneal artery and the posterior tibialis artery. Nerve injury to the FHL muscle is unlikely during flap harvest.

Mapping the columns of the acetabulum--implications for percutaneous fixation.

Knowledge of the bony thickness of the acetabular columns is one requisite for safe execution of percutaneous fixation of acetabular fractures. We performed a cadaveric study to determine anatomical dimensions of the columns of acetabulum with reference to percutaneous screw fixation. Twenty-two hemipelves (11 pairs) from 6 male and 5 female cadavers were measured and statistically analysed. In the anterior column, the psoas groove displayed the least vertical thickness of 15.1mm (range, 12.1-18.2mm), followed by the obturator canal with 15.9 mm (range, 12.2-20.6mm). The mean thickness of the posterior column wall of the acetabulum along the screw path displayed 21.3mm (range, 16.5-30.3mm). This study provides a clinical map for safe passage of both antegrade and retrograde percutaneous screws. Anatomic data suggests that 7.3mm cannulated screws can be safely accommodated by the anterior and posterior columns of the acetabulum.

Outside-in transobturator midurethral sling and the dorsal nerve of the clitoris.

INTRODUCTION AND HYPOTHESIS: An anatomical study on fresh cadavers was done to determine the vulnerability of the dorsal nerve of the clitoris to injury during "outside-in" transobturator sling procedures. METHODS: The dorsal nerve of the clitoris was identified bilaterally in ten fresh cadavers. Transfixing needles marked the inferomedial border of the obturator foramen. The distance between the foramen border and the nerve was measured. RESULTS: The nerve ran medially in close approximation to the ischiopubic ramus and inferior to the obturator foramen in all specimens. In no instance did the nerve follow an aberrant course traversing the obturator foramen. The mean distance between the inferomedial border of the obturator foramen and the nerve was 9.3 mm, range 3-14 mm. CONCLUSIONS: When the "outside-in" technique is used, the introducer cannot come into contact with the dorsal nerve of the clitoris because the introducer would have to pass through the ischio-pubic ramus. This is not anatomically possible.

Anterior transposition of the radial nerve--a cadaveric study.

OBJECTIVE: The radial nerve is at risk during the posterior plating of the humerus. The purpose of this anatomic study was to assess the extent of radial nerve dissection required for anterior transposition through the fracture site (transfracture anterior transposition). METHODS: A cadaver study was conducted approaching the humerus by a posterior midline incision. The extent of dissection of the nerve necessary for plate fixation of the humerus fracture was measured. An osteotomy was created to model a humeral shaft fracture at the spiral groove (OTA classification 12-A2, 12-A3). The radial nerve was then transposed anterior to the humeral shaft through the fracture site. The additional dissection of the radial nerve and the extent of release of soft tissue from the humerus shaft to achieve the transposition were measured. RESULTS: Plating required a dissection of the radial nerve 1.78 cm proximal and 2.13 cm distal to the spiral groove. Transfracture anterior transposition of the radial nerve required an average dissection of 2.24 cm proximal and 2.68 cm distal to the spiral groove. The lateral intermuscular septum had to be released for 2.21 cm on the distal fragment to maintain laxity of the transposed nerve. CONCLUSIONS: Transfracture anterior transposition of the radial nerve before plating is feasible with dissection proximal and distal to the spiral groove and elevation of the lateral intermuscular septum. Potential clinical advantages of this technique include enhanced fracture site visualization, application of broader plates, and protection of the radial nerve during the internal fixation.

The inguinal ligament and its lateral attachments: correcting an anatomical error.

The inguinal portions of the internal oblique and transversus abdominis muscles are generally described as arising from the inguinal ligament. Previous authors have shown that this description is incorrect. A new dissection study in 15 lightly embalmed cadavers confirms that in reality the inguinal portions of these muscles arise from a thickened strip of ilipsoas fascia that forms the superolateral part of the ilio-pectineal arch. Details are given of a new dissection technique that fully exposes the deep aspect of the inguinal ligament, without disrupting its continuity. The historical background of the persistent textbook error is explored. It originated at a time when there was widespread descriptive and semantic confusion regarding the structure now known as the inguinal ligament.

Anterior versus posterior pin placement of pelvic C-clamp in relationship to anatomical structures: a cadaver study.

OBJECTIVES: The objective of this study was to compare anterior and posterior pin placement of the pelvic C-clamp with specific reference to the proximity of the sciatic nerve, sciatic notch, hip joint capsule, and superior gluteal neurovascular bundle. METHODS: The pelvic C-clamp (Synthes, Paoli, PA) was applied to eight extracted pelvic specimens and five full cadavers (26 hips in total). Anterior and posterior pin placements were measured in relationship to the described anatomical structures. RESULTS: In 100% of the hips the distance from the posterior pin to the hip joint capsule was in 21 (80.8%), 23 (88.5%), and 20 (76.9%) of the hips, the anterior pin distances were greater than the posterior pin distances to the sciatic nerve, sciatic notch, and superior gluteal neurovascular bundle, respectively. CONCLUSIONS: Anterior pin placement is further from all anatomical structures studies with the exception of the hip joint capsule. The posterior pin was closer to the sciatic nerve, sciatic notch, and superior gluteal neurovascular bundle in all cases. Clinical decision-making for C-clamp placement should be individualised on a case-by-case basis.

The cutaneous arteries of the anterior abdominal wall: a three-dimensional study.

BACKGROUND: Abdominal perforator flaps represent a natural progression in the quest to minimize abdominal wall morbidity. Their one disadvantage is the significant rate of vascular complications to which they are subject in some series. The authors examined the vascular anatomy of the abdominal integument, to determine why such complications occur and how they may be prevented. METHODS: In 10 fresh cadavers, major arteries supplying the abdominal wall were injected with a lead-based contrast medium. The abdominal integument of each cadaver was imaged using a 16-slice spiral computed tomography scanner, to produce three-dimensional reconstructions of the arterial anatomy. Reconstructions were observed for orientation, course, and morphology of the major perforators within the abdominal integument. RESULTS: Perforators of the deep inferior epigastric artery (DIEA) varied markedly in their orientation, course, and morphology among specimens. By contrast, perforators of the superior epigastric artery (SEA) were relatively consistent in their morphology and orientation. In eight of 10 specimens, SEA perforators with extensive anatomical "territories" orientated toward the umbilicus were present. These SEA perforators pierced the rectus sheath within 4 cm of the costal margin and were present bilaterally in seven of eight specimens. CONCLUSIONS: The unpredictable orientation and course of DIEA perforators indicate that the blood supply of abdominal perforator flaps, raised without clear knowledge of their unique vascular anatomy, may often be more random than axial. This may account for much of the ischemia-related morbidity observed with DIEA-based perforator flaps. Preservation of SEA perforators adjacent to the costal margin during abdominoplasty will likely improve abdominal wall perfusion and reduce donor-site morbidity.

Three-dimensional CT angiography: a new technique for imaging microvascular anatomy.

To date there has been no satisfactory research method for imaging microvascular anatomy in three dimensions (3D). In this article we present a new technique that allows both qualitative and quantitative examination of the microvasculature in 3D. In 10 fresh cadavers (7 females, 3 males, mean age 68 years), selected arteries supplying the abdominal wall and back were injected with a lead oxide/gelatin contrast mixture. From these regions, 30 specimens were dissected free and imaged with a 16-slice spiral computed tomographic (CT) scanner. Using three-dimensional CT (3D-CT) angiography, reconstructions of the microvasculature of each specimen were produced and examined for their qualitative content. Two calibration tools were constructed to determine (1) the accuracy of linear measurements made with CT software tools, and (2) the smallest caliber blood vessel that is reliably represented on 3D-CT reconstructions. Three-dimensional CT angiography produced versatile, high quality angiograms of the microvasculature. Correlation between measurements made with electronic calipers and CT software tools was very high (Lin's concordance coefficient, 0.99 (95% CI 0.99-0.99)). The finest caliber of vessel reliably represented on the 3D-CT reconstructions was 0.4 mm internal diameter. In summary, 3D-CT angiography is a simple, accurate, and reproducible method that imparts a much improved perception of anatomy when compared with existing research methods. Measurement tools provide accurate quantitative data to aid vessel mapping and preoperative planning. Further work will be needed to explore the full utility of 3D-CT angiography in a clinical setting.

The use of lightly embalmed (fresh tissue) cadavers for resident laparoscopic training.

STUDY OBJECTIVE: The value of a cadaver training program in laparoscopic surgery has rarely been studied. As there is a dearth of cadaver training programs, it is important to evaluate them. The goal of this study was to estimate if our cadaver training program significantly and relatively rapidly taught residents laparoscopic surgical skills. DESIGN: Observational, timed comparative study (Canadian Task Force classification II-3). SETTING: University of Louisville School of Medicine, Fresh Tissue Laboratory, Louisville, KY. PARTICIPANTS: Twenty-nine obstetric/gynecology residents (15 postgraduate year PGY 2 and 14 PGY 3) participated in the study. INTERVENTION: During 5 half days, we compared the performance of each postgraduate year (PGY) 2 and PGY 3 obstetric/gynecology resident to his or her own results on five outcome skills before and after training in lightly embalmed cadavers. The testing was performed at the beginning and at the end of the week so that all improvement was secondary only to the training experience with the cadaver. Residents were assessed using laparoscopic techniques in a physical-reality simulator for three outcomes: bead transfer time, number of beads transferred, and suturing time on a stuffed vinyl glove and in two specific areas of the cadaver pelvis, with one slightly more difficult than the other. Assessment of suturing time was made on the two distinct tasks using the embalmed cadavers. Although the number of residents was relatively small, it covered two levels for one year. MEASUREMENTS AND MAIN RESULTS: The residents were assessed on a simulator before and after laparoscopic surgical training on the cadaver. The median decrease in bead transfer time (task I, simulator) was 38.5 seconds (p=.02); 69% of the residents showed some reduction in time to complete this task. The median increase in the number of beads transferred (task II, simulator) was 2.5 beads (p=.0001); 72.4% of the residents transferred at least one more bead after training. The median decrease in suture time (task III, simulator) was 63.5 seconds (p=.001); 79.3% of the residents performed this task more quickly after training. The median decrease in suture time (task IV, cadaver) was 54.5 seconds (p=.001); 72.4% of the residents showed improved performance on this task after training. The median reduction in suture time (task V, cadaver) was 53.5 seconds (p<.001); 82.8% of the residents completed this task more quickly after training. CONCLUSIONS: This cadaver surgical training program appeared to significantly improve laparoscopic surgical techniques in PGY 2 and PGY 3 obstetric/gynecology residents in a relatively short time. This model teaches residents specific training in the handling and manipulation of tissue as well as practice in surgical techniques for adnexal surgery, pelvic dissection, laparoscopic hysterectomy, and dissection within the space of Retzius that is not possible with mechanical trainers.

Scapular thickness--implications for fracture fixation.

The purpose of this study was to measure and map scapula osseous thickness to identify the optimal areas for internal fixation. Eighteen (9 pairs) scapulae from 2 female and 7 male cadavers were used. After harvest and removal of all soft tissues, standardized measurement lines were made based on anatomic landmarks. For consistency among scapulae, measurements were taken at standard percentage intervals along each line approximating the distance between two consecutive reconstruction plate screw holes. Two-mm-diameter drill holes were made at each point, and a standard depth gauge was used to measure thickness. The glenoid fossa (25 mm) displayed the greatest mean osseous thickness, followed by the lateral scapular border (9.7 mm), the scapula spine (8.3 mm), and the central portion of the body of the scapula (3.0 mm). To optimize screw purchase and internal fixation strength, the lateral border, the lateral aspect of the base of the scapula spine, and the scapula spine itself should be used for anatomic sites of internal fixation of scapula fractures.

Determining the relationship of the axillary nerve to the shoulder joint capsule from an arthroscopic perspective.

BACKGROUND: The axillary nerve is out of the field of view during shoulder arthroscopy, but certain procedures require manipulation of capsular tissue that can threaten the function or integrity of the nerve. We studied fresh cadavers to identify the course of the axillary nerve in relation to the glenoid rim from an intra-articular perspective and to determine how close the nerve travels in relation to the glenoid rim and the inferior glenohumeral ligament. METHODS: We dissected nine whole-body fresh-tissue shoulder joints and exposed the axillary nerve through a window in the inferior glenohumeral ligament. Then we cut coronal sections through the glenoid fossa of ten unembalmed, frozen shoulder specimens after the axillary nerve had been stained with Evans blue dye. All specimens were studied with the joint secured in the lateral decubitus position used for shoulder arthroscopy. RESULTS: Microsurgical dissection through the inferior glenohumeral ligament from within the joint capsule revealed the axillary nerve as it traversed the quadrangular space. In each dissection, the teres minor branch was the closest to the glenoid rim. The coronal sectioning of the unembalmed shoulder specimens demonstrated that the closest point between the axillary nerve and the glenoid rim was at the 6 o'clock position on the inferior glenoid rim. At this position, the average distance between the axillary nerve and the glenoid rim was 12.4 mm. The axillary nerve lay, throughout its course, at an average of 2.5 mm from the inferior glenohumeral ligament. CONCLUSIONS: We used two novel approaches to map the axillary nerve from an intra-articular perspective. Our analysis of the position of the nerve with use of these methods provides the shoulder arthroscopist with essential information regarding the location, route, and morphology of the nerve as it passes inferior to the glenoid rim and shoulder capsule.

Mesorectal lymph nodes: their location and distribution within the mesorectum.

PURPOSE: Total mesorectal excision is an alternative surgical approach for resectable rectal cancer and is associated with favorable results and a low rate of local recurrence. Despite the popularity of this technique, few data exist regarding the location and distribution of lymph nodes within the rectal mesentery. The purpose of this study was to define the distribution, size, and location of lymph nodes within the mesorectum and on the pelvic side wall. METHODS: Seven fresh cadavers at our institution's Fresh Tissue Dissection Laboratory were studied. The rectum, its mesentery, and all fatty tissue from both pelvic side walls were removed and placed in a lymph node clearing solution for 24 hours. After appropriate dissection, the distribution, size, and location of lymph nodes within the rectal mesentery and pelvic side wall tissue were documented. RESULTS: A total of 174 lymph nodes were identified (approximately 25 per patient). The majority (>80 percent) of lymph nodes were smaller than 3 mm in diameter. Fifty-six percent of the nodes within the rectal mesentery were located in the posterior mesentery, and most were located in the upper two-thirds of the posterior rectal mesentery. CONCLUSIONS: The majority of perirectal lymph nodes are small. There are few lymph nodes within the mesentery of the lower third of the rectum and relatively few in the right and left lateral portions of the mesorectum. We confirm that the majority of nodes are located in the proximal two-thirds of the posterior rectal mesentery. It is possible that removal of these nodes is responsible for the superior oncologic results found with total mesorectal excision in contrast to more traditional surgical techniques.

Anatomical evidence for the absence of a morphologically distinct cranial root of the accessory nerve in man.

The accessory nerve is conventionally described as having a cranial and spinal root. According to standard descriptions the cranial root (or part) is formed by rootlets that emerge from the medulla between the olive and the inferior cerebellar peduncle. These rootlets are considered to join the spinal root, travel with it briefly, then separate within the jugular foramen to become part of the vagus nerve. In 15 fresh specimens we exposed the posterior cranial fossa with a coronal cut through the foramen magnum and explored the course of each posterior medullary rootlet (PMR) arising from within the retro-olivary groove. We chose the caudal end of the olive as the landmark for the caudal end of the medulla. In all specimens every PMR that did not contribute to the glossopharyngeal nerve joined the vagus nerve at the jugular foramen. The distance between the caudal limit of the olive and the origin of the most caudal PMR that contributed to the vagus nerve ranged from 1-21 mm (mean = 8.8 mm). All rootlets that joined the accessory nerve arose caudal to the olive. The distance from the caudal limit of the olive and the most rostral accessory rootlet ranged from 1-15 mm (mean = 5.4 mm). We were unable to demonstrate any connection between the accessory and vagus nerves within the jugular foramen. Our findings indicate that the accessory nerve has no cranial root; it consists only of the structure hitherto referred to as its spinal root.