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Mohammadali M. Shoja and Joshua J. Chern

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Martin M. Mortazavi, Andrew K. Romeo, Aman Deep, Christoph J. Griessenauer, Mohammadali M. Shoja, R. Shane Tubbs and Winfield Fisher

Object

Currently, mannitol is the recommended first choice for a hyperosmolar agent for use in patients with elevated intracranial pressure (ICP). Some authors have argued that hypertonic saline (HTS) might be a more effective agent; however, there is no consensus as to appropriate indications for use, the best concentration, and the best method of delivery. To answer these questions better, the authors performed a review of the literature regarding the use of HTS for ICP reduction.

Methods

A PubMed search was performed to locate all papers pertaining to HTS use. This search was then narrowed to locate only those clinical studies relating to the use of HTS for ICP reduction.

Results

A total of 36 articles were selected for review. Ten were prospective randomized controlled trials (RCTs), 1 was prospective and nonrandomized, 15 were prospective observational trials, and 10 were retrospective trials. The authors did not distinguish between retrospective observational studies and retrospective comparison trials. Prospective studies were considered observational if the effects of a treatment were evaluated over time but not compared with another treatment.

Conclusions

The available data are limited by low patient numbers, limited RCTs, and inconsistent methods between studies. However, a greater part of the data suggest that HTS given as either a bolus or continuous infusion can be more effective than mannitol in reducing episodes of elevated ICP. A meta-analysis of 8 prospective RCTs showed a higher rate of treatment failure or insufficiency with mannitol or normal saline versus HTS.

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Christoph J. Griessenauer, R. Shane Tubbs, Mohammadali M. Shoja, Joel Raborn, Christopher J. Boes, Martin M. Mortazavi and Giuseppe Lanzino

Alfred W. Adson was a pioneer in the field of neurosurgery. He described operations for a variety of neurosurgical diseases and developed surgical instruments. Under his leadership the Section of Neurological Surgery at the Mayo Clinic was established and he functioned as its first chair. Adson's contributions to the understanding of spinal and spinal cord tumors are less well known. This article reviews related medical records and publications and sets his contributions in the context of the work of other important pioneers in spinal tumor surgery at the time.

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R. Shane Tubbs, Joshua M. Beckman, Marios Loukas, Mohammadali M. Shoja and Aaron A. Cohen-Gadol

Object

Various donor nerves have been used for brachial plexus neurotization procedures. To the authors' knowledge, neurotization of median nerve branches to the pronator teres to the radial nerve at the elbow have not been explored.

Methods

In an attempt to identify an additional nerve donor candidate for neurotization procedures of the upper limb, 20 cadaveric upper limbs underwent dissection of the cubital fossa and identification of branches of the median nerve to the pronator teres. Measurements were made of such branches, and distal transection was then performed to determine the appropriate length so that the structure could be brought to the laterally positioned radial nerve via tunneling deep to the biceps brachii muscle.

Results

All specimens were found to have a median nerve branch to the pronator teres that was long enough to reach the radial nerve in the cubital fossa. Neural connections remained tension free with full pronation and supination. The mean length of these branches to the pronator teres was 3.6 cm. The overall mean diameter of these nerves was 1.5 mm. The mean proximal, midpoint, and distal diameters were 2.0, 1.8, and 1.5 mm, respectively. The mean distance between the origin of these branches to the pronator teres and the medial epicondyle of the humerus was 4.1 cm.

Conclusions

Based on the results of our cadaveric study, the use of the branch of the median nerve to the pronator teres muscle may be considered for neurotization of the radial nerve in the cubital fossa.

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R. Shane Tubbs, Martin M. Mortazavi, Marios Loukas, Mohammadali M. Shoja and Aaron A. Cohen-Gadol

Object

Knowledge of the detailed anatomy of the craniocervical junction is important to neurosurgeons. To the authors' knowledge, no study has addressed the detailed anatomy of the intracranial (first) denticulate ligament and its intracranial course and relationships.

Methods

In 10 embalmed and 5 unembalmed adult cadavers, the authors performed posterior dissection of the craniocervical junction to expose the intracranial denticulate ligament. Rotation of the spinomedullary junction was documented before and after transection of unilateral ligaments.

Results

The first denticulate ligament was found on all but one left side and attached to the dura of the marginal sinus superior to the vertebral artery as it pierced the dura mater. The ligament always traveled between the vertebral artery and spinal accessory nerve. On 20% of sides, it also attached to the intracranial vertebral artery and, histologically, blended with its adventitia. In general, this ligament tended to be thicker laterally and was often cribriform in nature medially. The hypoglossal nerve was always superior to the ligament, which always concealed the ventral roots of the C-1 spinal nerve. The posterior spinal artery traveled posterior to this ligament on 93% of sides. On one left side, the ascending branch of the posterior spinal artery traveled anterior to the ligament and the descending branch traveled posterior to it. Following unilateral transection of the intracranial denticulate ligament, rotation of the spinomedullary junction was increased by approximately 25%.

Conclusions

Knowledge of the relationships of the first denticulate ligament may prove useful to the neurosurgeon during procedures at the craniocervical junction.

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R. Shane Tubbs, Martin M. Mortazavi, Mohammadali M. Shoja, Marios Loukas and Aaron A. Cohen-Gadol

Object

Additional nerve transfer options are important to the peripheral nerve surgeon to maximize patient outcomes following nerve injuries. Potential regional donors may also be injured or involved in the primary disease. Therefore, potential contralateral donor nerves would be desirable. To the authors' knowledge, use of the contralateral spinal accessory nerve (SAN) has not been explored for ipsilateral neurotization procedures. In the current study, therefore, the authors aimed to evaluate the SAN as a potential donor nerve for contralateral nerve injuries by using a novel technique.

Methods

In 10 cadavers, the SAN was harvested using a posterior approach, and tunneled subcutaneously to the contralateral side for neurotization to various branches of the brachial plexus. Measurements were made of the SAN available for transfer and of its diameter.

Results

The authors found an SAN length of approximately 20 cm (from transition of upper and middle fibers of the trapezius muscle to approximately 2–4 cm superior to the insertion of the trapezius muscle onto the spinous process of T-12) available for nerve transposition. The average diameter was 2.5 mm.

Conclusions

Based on these findings, the contralateral SAN may be considered for ipsilateral neurotization to the suprascapular and axillary nerves.

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R. Shane Tubbs, Martin M. Mortazavi, Marios Loukas, Mohammadali M. Shoja and Aaron A. Cohen-Gadol

Object

Knowledge of the variations in the nerves of the posterior cranial fossa may be important during skull base approaches. To the authors' knowledge, intracranial neural interconnections between the glossopharyngeal and vagus nerves have not been previously investigated.

Methods

The senior author (A.C.G.) noted the presence of an intracranial interneural connection between the glossopharyngeal and vagus nerves during microvascular decompression surgery in a patient suffering from hemifacial spasm. To further investigate the approximate incidence and significance of such an interneural connection, the authors studied 40 adult human cadavers (80 sides) and prospectively evaluated 16 additional patients during microvascular procedures of the posterior cranial fossa.

Results

In the cadavers, the incidence of intracranial neural connections between the glossopharyngeal and vagus nerves was 2.5%. The only such connection found in our series of living patients was in the patient in whom the connection was initially identified. These interconnections were more common on the left side. Based on our findings, we classified these neural connections as Types I and II. In the cadavers, the length and width of this connection were approximately 9 mm and 1 mm, respectively. Histological analysis of these connections verified their neural content.

Conclusions

Although these connections are rare and the significance is unknown, knowledge of them may prove useful to surgeons who operate in the posterior fossa region so that they may avoid inadvertent traction or transection of these interconnections. Additionally, such connections might be considered in patients with recalcitrant neuralgia after microvascular decompression and rhizotomy of the glossopharyngeal nerve.

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R. Shane Tubbs, Mohammadali M. Shoja, Marios Loukas, W. Jerry Oakes and Aaron Cohen-Gadol

William Henry Battle (1855–1936) practiced medicine in England > 1 century ago and is primarily remembered for his description of ecchymosis over the mastoid, which indicates fracture of the skull base. Although Mr. Battle made many contributions to medicine, almost nothing exists in the literature regarding his life and findings, especially in regard to head injury. The following is a review of Battle's background and his contributions to medicine, specifically his observations associated with basilar skull fractures.

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Daniel H. Fulkerson, Ahilan Sivaganesan, Jason D. Hill, John R. Edwards, Mohammadali M. Shoja, Joel C. Boaz and Andrew Jea

Object

The physiological reaction of CSF white blood cells (WBCs) over the course of treating a shunt infection is undefined. The authors speculated that the CSF WBC count varies with different infecting organisms in peak level and differential percentage of polymorphonuclear (PMN) leukocytes, lymphocytes, monocytes, and eosinophils. The authors hope to identify clinically useful trends in the progression of CSF WBCs by analyzing a large group of patients with successfully treated shunt infections.

Methods

The authors reviewed 105 successfully treated cases of shunt infections at Riley Hospital for Children. The study dates ranged from 2000 to 2004; this represented a period prior to the routine use of antibiotic-impregnated shunt catheters. They analyzed the following organisms: coagulase-negative staphylococci, Staphylococcus aureus, Propionibacterium acnes, Streptococcal species, and gram-negative organisms. The initial CSF sample at diagnosis was analyzed, as were levels over 14 days of treatment. Model fitting was performed to generate curves for the expected progression of the WBC counts and the differential PMN leukocytes, lymphocyte, monocyte, and eosinophil percentages.

Results

Gram-negative organisms resulted in a higher initial (p = 0.03) and peak WBC count with a greater differential of PMN leukocytes compared with other organisms. Propionibacterium acnes infections were associated with a significantly lower WBC count and PMN leukocytes percentage (p = 0.02) and higher eosinophil percentage (p = 0.002) than other organisms. The pattern progression of the CSF WBC count and differential percentages was consistent for all infections. There was an initial predominance of PMN leukocytes, followed by a delayed peak of lymphocytes, monocytes, and eosinophils over a 14-day course. All values trended toward zero over the treatment course.

Conclusions

The initial and peak levels of CSF WBCs vary with the infecting organisms. The CSF cell counts showed a predictable pattern during the treatment of shunt infection. These trends may be useful to the physician in clinical decision making, although there is a wide range of variability.

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R. Shane Tubbs, Joshua Dixon, Marios Loukas, Mohammadali M. Shoja and Aaron A. Cohen-Gadol

Object

Knowledge of the anatomy of the ligaments that unite the head with the neck is important to the clinician who treats patients with lesions in this region. Although the anatomy and function of these ligaments have been well described, those of the Barkow ligament (BL) have yet to be studied.

Methods

Via an anterior approach, 13 unembalmed adult cadavers underwent dissection of the craniocervical junction with special attention to the presence, anatomy, and function of the BL.

Results

The BL was found in 92.3% of specimens. The attachment of each ligament onto the medial aspect of the occipital condyle was consistent and just anterior to the attachment of the alar ligaments. In 75% of specimens, there was some connection between the BL and the anterior atlantooccipital membrane. Connections between other adjacent ligamentous structures were not identified. The average width, length, and thickness of the BL were 4, 2.5, and 3.5 mm, respectively. With ranges of motion of the craniocervical junction, only extension of the atlantooccipital joint produced tension in the BL. The mean tension to failure of the ligament was 28 N. Statistical analysis revealed no significant difference in width, length, and thickness of the ligaments based on sex.

Conclusions

The BL was found in all but 1 of our specimens. This ligament appears to resist extension of the atlantooccipital joint and may be synergistic with the anterior atlantooccipital membrane. Interestingly, the function of this ligament as found in this study relies on the integrity of the transverse ligament. Knowledge of this ligament may aid in further understanding craniocervical stability and help in differentiating normal from pathological tissue using imaging modalities.