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  • Author or Editor: Robert G. Louis Jr x
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David N. Louis, E. P. Richardson Jr., G. Richard Dickersin, Debra A. Petrucci, Andrew E. Rosenberg and Robert G. Ojemann

✓ A case of primary intracranial leiomyosarcoma is presented, with clinical, radiological, light microscopic, immunohistochemical, and ultrastructural data. The histogenesis is discussed and the literature on smoothmuscle tumors of the central nervous system is reviewed.

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Robert G. Louis Jr., Chun Po Yen, Carrie A. Mohila, James W. Mandell and Jason Sheehan

The authors report the case of a patient with an intraosseous spinal arteriovenous malformation (AVM) presenting as an epidural mass lesion that was causing spinal cord compression. The 59-year-old woman had bilateral numbness, weakness, and hyperreflexia of both legs. Magnetic resonance imaging revealed intermediate T1 signal and hyperintense T2 signal involving the right transverse process, bilateral pedicles, and T-5 spinous process; the lesion's epidural extension was causing severe canal compromise and cord displacement. Coil embolization was performed, and the patient underwent resection, after which preoperative symptoms improved. Histopathological analysis revealed a benign vascular proliferation consistent with an intraosseous spinal AVM. On review of the literature, the authors found this case to be the second intraosseous spinal AVM, and the first in a patient whose clinical presentation was consistent with that of a mass lesion of the bone.

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Robert Dallapiazza, Aaron E. Bond, Yuval Grober, Robert G. Louis, Spencer C. Payne, Edward H. Oldfield and John A. Jane Jr.

Object

The object of this study was to compare surgical outcomes and complications in a contemporaneous series of patients undergoing either microscopic or endoscopic transsphenoidal surgery for nonfunctioning pituitary macroadenomas without imaging evidence of cavernous sinus invasion.

Methods

This is a retrospective analysis of a prospectively collected database from a single institution. Data were collected from patients whose surgery had occurred in the period from June 2010 to January 2013. Patients who underwent microscopic or endoscopic surgery for Knosp Grade 0, 1, or 2 nonfunctioning pituitary macroadenomas were included in the study. Patients who had clinically secreting or Knosp Grade 3 or 4 tumors and patients who were undergoing revision surgery were excluded from analysis. Eligible patient records were analyzed for outcomes and complications. Statistical analyses were performed on tumor volume, intraoperative factors, postoperative complications, and degree of resection on 1-year postoperative MRI. The results were used to compare the outcomes after microscopic and endoscopic approaches.

Results

Forty-three patients underwent microscopic transsphenoidal surgery, and 56 underwent endoscopic transsphenoidal surgery. There were no statistical differences in the intraoperative extent of resection or endocrinological complications. There were significantly more intraoperative CSF leaks in the endoscopic group (58% vs 16%); however, there was no difference in the incidence of postoperative CSF rhinorrhea (12% microscopic vs 7% endoscopic). Length of hospitalization was significantly shorter in patients undergoing an endoscopic approach (3.0 days vs 2.4 days). Two-month follow-up imaging was available in 95% of patients, and 75% of patients had 1-year follow-up imaging. At 2 months postprocedure, there was no evidence of residual tumor in 79% (31 of 39) and 85% (47 of 55) of patients in the microscopic and endoscopic groups, respectively. At 1 year postprocedure, 83% (25 of 30) of patients in the microscopic group had no evidence of residual tumor and 82% (36 of 44) of those in the endoscopic group had no evidence of residual tumor.

Conclusions

The microscopic and endoscopic techniques provide similar outcomes in the surgical treatment of Knosp Grades 0–2 nonfunctioning pituitary macroadenomas.

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R. Shane Tubbs, Christopher T. Wartmann, Robert G. Louis Jr., Mohammadali M. Shoja, Jason Cormier and Marios Loukas

Object

Graft sources for lumbar fusion include synthetic materials, donor grafts, and autologous bone such as the iliac crest. Considering the data indicating that autologous bone grafts generate the best results for fusion, the next logical step is to seek alternative donor sites in an attempt to reduce the complications associated with these procedures. To the authors' knowledge, autologous scapula has not been explored as a potential source for posterior lumbar fusion graft material. Therefore, the following study was performed to verify the utility of this bone in these procedures.

Methods

Six adult cadavers (mean age 71 years), four formalin-fixed and two fresh specimens, were used in this study. With the cadaver in the prone position, an incision was made over the spine of the scapula. Soft tissues were stripped from the middle of this region of the scapula, and bone segments were removed with a bone saw and used for a posterior lumbar fusion procedure.

Results

A mean length of 11.5 cm was measured for the spine of the scapula and the mean thicknesses of this bone at its medial part, segment just medial to the spinoglenoid notch, and acromion were 1 cm, 2.2 cm, and 2.5 cm, respectively. No obvious injury to surrounding vessels or nerves was found using this procedure, and adequate fusion was achieved with it.

Conclusions

Following clinical testing, such a bone substitute as autologous scapular spine might be a reasonable alternative to iliac crest grafts for use in posterior lumbar fusion procedures.

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R. Shane Tubbs, William Stetler, Robert G. Louis Jr., Ankmalika A. Gupta, Marios Loukas, David R. Kelly, Mohammadali M. Shoja and Aaron A. Cohen-Gadol

Object

The spinal accessory nerve (SAN) has been reported to have a distinctly coiled appearance in its course through the posterior cervical triangle of the neck. As this is unusual compared with other peripheral nerves including the cranial nerves, the present histological analysis was performed to further elucidate the reason for this anatomy with potential application in nerve injury and repair.

Methods

Ten adult cadavers underwent dissection of the neck. The SAN was harvested proximally and within the posterior cervical triangle. For comparison with other cranial nerves within the neck, the cervical vagus and hypoglossal nerves were also harvested. All nerves underwent histological analysis. Additionally, 2 human fetuses (11 and 20 weeks' gestation) underwent examination of the SAN in the posterior cervical triangle, and 3 randomly selected specimens were submitted for electromicroscopy.

Results

All SANs were found to have a straight gross configuration proximal to the posterior triangle and a coiled appearance within this geometrical area. Histologically, no differences were identified for the SAN in these 2 locations (that is, proximal to and within the posterior cervical triangle). The histology of the SAN both with routine analysis and electron microscopy was similar in both regions and to nerves used as controls (for example, vagus and hypoglossal nerves). Interestingly, both fetal specimens were found to have coiled SANs in the posterior cervical triangle.

Conclusions

Based on this study, it appears that the tortuous course of the SAN in the posterior triangle arises from functional as opposed to structural forces. It is hoped that this analysis will provide some insight into the nature behind the morphology observed in the SAN within the posterior cervical triangle and aid in future investigations regarding its injury. Moreover, such a coiled nature of this nerve may assist the neurosurgeon in identifying it during, for example, neurotization procedures.

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R. Shane Tubbs, Marios Loukas, Robert G. Louis Jr., Mohammadali M. Shoja, Cameron S. Askew, April Phantana-Angkool, E. George Salter and W. Jerry Oakes

Object

The basal vein of Rosenthal (BV) courses from the premesencephalic cistern, through the ambient cistern, and terminates in the quadrigeminal cistern. The aim of this study was to describe and quantitate the surgical anatomy of this structure and specifically to provide landmarks for identifying this vessel along its course. These data may be of use, for example, to surgeons using subtemporal operative approaches through regions where this vessel is concealed.

Methods

The authors examined 15 latex-injected adult cadaveric brains (30 sides) to delineate the morphological characteristics of the BV. Dissections of the BV were then performed and measurements were made between this structure and the tentorial incisura at the anterior, middle, and posterior borders of the lateral midbrain.

All specimens were found to have a left and right BV with varying morphological characteristics. The mean distance between the BV and posterior cerebral artery at the midpoint of the lateral midbrain was 16 mm. The BV was always found superomedial to the posterior cerebral artery along the lateral aspect of the midbrain, and the BV ranged in diameter from 1 to 5 mm. The BV drained into the vein of Galen in all but two specimens. The mean distances from the tentorial edge to the BV at the anterior, middle, and posterior borders of the lateral midbrain were 11, 13, and 4 mm, respectively. No statistically significant differences were found when comparing left and right sides or male and female specimens.

Conclusions

The authors hope that these data will help the neurosurgeon operating near the BV to avoid injury to this important structure.

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Marios Loukas, Robert G. Louis Jr., Lynsey Stewart, Barry Hallner, Terry DeLuca, Walter Morgan, Ranjil Shah and Jim Mlejnek

Object

Sensation in the palmar surface of the digits is supplied by the median and ulnar nerves, with the boundary classically being the midline of the ring finger. Overlap and variations of this division exist, and a communicating branch between the ulnar and median nerve could potentially explain further variations in digital sensory innervations. The aim of this study was to examine the origin and distribution of the communicating branch between the ulnar and median nerves and to apply such findings to the risk involved in surgical procedures in the hand.

Methods

The authors grossly and endoscopically examined 200 formalin-fixed adult human hands obtained in 100 cadavers, and a communicating branch was found to be present in 170 hands (85%). Of the specimens with communicating branches, the authors were able to identify four notable types representing different points of connections of the branches. The most common, Type I (143 hands, 84.1%), featured a communicating branch that originated proximally from the ulnar nerve and proceeded distally to join the median nerve. Type II (12 hands, 7.1%) designated a communicating branch that originated proximally from the median nerve and proceeded distally to join the ulnar nerve. Type III (six hands, 3.5%) designated a communicating branch that traversed perpendicularly between the median and ulnar nerves in such a way that it was not possible to determine which nerve served as the point of origin. Type IV (nine hands, 5.3%) designated a mixed type in which multiple communicating branches existed, arising from both ulnar and median nerves.

Conclusions

According to the origin and distribution of these branching patterns, the investigators were able to define a risk area in which the communicating branch(es) may be subject to iatrogenic injury during common hand procedures.

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R. Shane Tubbs, Robert G. Louis Jr., Christopher T. Wartmann, Marios Loukas, Mohammadali M. Shoja, Mohammad R. Ardalan and W. Jerry Oakes

Object

Facial nerve injury with resultant facial muscle paralysis is disfiguring and disabling. To the auhtors' knowledge, neurotization of the facial nerve using a branch of the brachial plexus has not been previously performed.

Methods

In an attempt to identify an additional nerve donor candidate for facial nerve neurotization, 5 fresh adult human cadavers (10 sides) underwent dissection of the suprascapular nerve distal to the suprascapular notch where it was transected. The facial nerve was localized from the stylomastoid foramen onto the face, and the cut end of the suprascapular nerve was tunneled to this location. Measurements were made of the length and diameter of the supra-scapular nerve. In 2 of these specimens prior to transection of the nerve, a nerve-splitting technique was used.

Results

All specimens were found to have a suprascapular nerve with enough length to be tunneled, tension free, superiorly to the extracranial facial nerve. Connections remained tensionless with left and right head rotation of up to 45°. The mean length of this part of the suprascapular nerve was 12.5 cm (range 11.5–14 cm). The mean diameter of this nerve was 3 mm. A nerve-splitting technique was also easily performed. No gross evidence of injury to surrounding neurovascular structures was identified.

Conclusions

To the authors' knowledge, the suprascapular nerve has not been previously explored as a donor nerve for facial nerve reanimation procedures. Based on the results of this cadaveric study, the authors believe that use of the suprascapular nerve may be considered for surgical maneuvers.

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R. Shane Tubbs, Robert G. Louis Jr., Christopher T. Wartmann, Robert Lott, Gina D. Chua, David Kelly, Cheryl Ann Palmer, Mohamadali M. Shoja, Marios Loukas and W. Jerry Oakes

Object

To the best of the authors' knowledge, no report exists that has demonstrated the histopathological changes of neural elements within the brachial plexus as a result of cervical rib compression.

Methods

Four hundred seventy-five consecutive human cadavers were evaluated for the presence of cervical ribs. From this cohort, 2 male specimens (0.42%) were identified that harbored cervical ribs. One of the cadavers was found to have bilateral cervical ribs and the other a single right cervical rib. Following gross observations of the brachial plexus and, specifically, the lower trunk and its relationship to these anomalous ribs, the lower trunks were submitted for immunohistochemical analysis. Specimens were compared with two age-matched controls that did not have cervical ribs.

Results

The compressed plexus trunks were largely unremarkable proximal to the areas of compression by cervical ribs, where they demonstrated epi- and perineurial fibrosis, vascular hyalinization, mucinous degeneration, and frequent intraneural collagenous nodules. These histological findings were not seen in the nerve specimens in control cadavers. The epineurium was thickened with intersecting fibrous bands, and the perineurium appeared fibrotic. Many of the blood vessels were hyalinized. The nerve fascicles contained frequent intraneural collagenous nodules in this area, and focal mucinous degeneration was identified.

Conclusions

Cervical ribs found incidentally may cause histological changes in the lower trunk of the brachial plexus. The clinician may wish to observe or perform further evaluation in such patients.

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R. Shane Tubbs, Marios Loukas, Robert G. Louis Jr., Mohammadali M. Shoja, Leslie Acakpo-Satchivi, Jeffrey P. Blount, E. George Salter, W. Jerry Oakes and John C. Wellons III

Object

The superior and inferior sagittal sinuses have been well studied. Interestingly, other venous structures within the falx cerebri have received scant attention in the medical literature. The present study was performed to elucidate the presence and anatomy of these midline structures.

Methods

The authors examined 27 adult latex- or ink-injected cadaveric specimens to observe the morphological features of the sinuses within the falx cerebri (excluding the inferior and superior sagittal sinuses).

Results

All specimens were found to have an extensive network of small tributaries within the falx cerebri that were primarily concentrated in its posterior one third. In this posterior segment, these structures were usually more pronounced in the inferior two thirds. The portion of the falx cerebri not containing significant falcine venous sinus was termed a “safe area.” These vascular channels ranged in size from 0.5 mm to 1.1 cm (mean 0.6 mm); 100% of these vessels communicated with the inferior sagittal sinus. Classification of the structures was then performed based on communication of the falcine venous sinus with the superior sagittal sinus. Type I falcine sinuses had no communication with the superior sagittal sinus, Type II falcine sinuses had limited communication with the superior sagittal sinus, and Type III falcine sinuses had significant communication with the superior sagittal sinus. Seventeen (63%) of 27 specimens communicated with the superior sagittal sinus (Types II and III). Further subdivision revealed 10 Type I, seven Type II, and 10 Type III falcine venous plexuses.

Conclusions

There are other venous sinuses in the falx cerebri in addition to the superior and inferior sagittal sinuses. Neurosurgical procedures that necessitate incising or puncturing the falx cerebri can be done more safely via a described safe area. Given that the majority of specimens in the authors' study were found to have a plexiform venous morphology within the falx cerebri, they propose that these channels be referred to as the falcine venous plexus and not sinus. The falcine venous plexus should be taken into consideration by the neurosurgeon.