Faculty Bibliography

Cerebrospinal fluid (CSF) leaks result from a communication between the subarachnoid space and the upper aerodigestive tract. Because of the risk of complications such as meningitis, brain abscess, and pneumocephalus, all persistent CSF leaks should be repaired. Surgical repair may be achieved transcranially or extracranially using a wide variety of autogenous, allogenic, and synthetic patching materials. We report our results with a transnasal transsphenoidal endoscopic approach for the repair of CSF leaks coupled with a multilayer closure using acellular dermis (Allodermtrade mark). We conducted a retrospective review of all patients presenting to our institution over the past 5 years with isolated sphenoid sinus CSF fistulas. Results: Twenty-one patients were included in the study. Nineteen patients (90.5%) had their sphenoid sinus CSF fistula repaired during the first attempt; 2 patients (9.5%) needed a second attempt. The multilayer repair of the CSF leak using acellular dermis via a transsphenoidal endoscopic approach is an effective and successful method of surgical repair of the fistula site. Neither the number, size, nor cause of the CSF fistula affected surgical outcomes. However, the presence of hydrocephalus was a significant negative variable, altering the surgical outcomes of our patients. The acellular dermis offers the advantage of not requiring autogenous tissue for the effective repair of CSF leaks in the sphenoid sinus

OBJECT: Surgical access to tumors at the craniovertebral junction (CVJ) requires extensive bone removal. Guidelines for the use of occipitocervical fusion (OCF) after resection of CVJ tumors have been based on anecdotal evidence. The authors performed a retrospective study of factors associated with the use of OCF in 46 patients with CVJ tumors. The findings were used to develop recommendations for use of OCF in such patients. METHODS: The authors retrospectively reviewed the cases of 51 patients with CVJ tumors treated by their group between March 1991 and February 2004. Forty-six patients were available for follow up. Charts were reviewed to obtain data on demographic characteristics, presenting symptoms, and perioperative complications. Preoperative computerized tomography scans and magnetic resonance imaging studies were obtained in all patients. Occipitocervical fusion was performed in patients who had undergone a unilateral condyle resection in which 70% or more of the condyle was removed, a bilateral condyle resection with 50% removal, or C1-2 vertebral body destruction. Of the 46 patients, 16 had foramen magnum meningiomas, 17 had chordomas, one had a chondrosarcoma, two had Schwann cell tumors, two had glomus tumors, and eight had other types of tumors. Twenty-three (50%) of the 46 patients underwent OCF, including 15 of the 17 patients with chordomas (88%). None of the patients with meningiomas required fusion. Seventeen (71%) of the 24 patients presenting with neck pain preoperatively underwent OCF. CONCLUSIONS: Patients presenting with neck pain had a 71% chance of undergoing OCF. Patients with chordomas and metastatic tumors were most likely to require OCF. One patient with a 50% unilateral condylar resection returned with OC instability for which OCF was required. Based on their clinical experience and published biomechanical studies, the authors recommend that OCF be performed when 50% or more of one condyle is resected

OBJECT: Sphenoorbital meningiomas (SOMs) are complex tumors involving the sphenoid wing, orbit, and cavernous sinus, which makes their complete resection difficult or impossible. Sphenoidal hyperostosis that results in incomplete resection makes these tumors prone to high rates of recurrence with postoperative morbidity resulting in a nonfunctional globe. High-dose radiation therapy has often been described as the only treatment capable of achieving tumor control, although often at the expense of the patient's progressive visual deterioration. METHODS: This series consisted of 25 patients who were retrospectively analyzed over a 12-year period. Visual function was evaluated pre- and postoperatively in all patients. A standardized surgical approach to a frontotemporal craniotomy and orbitozygomatic osteotomy with intra- and extradural drilling of the optic canal and all the hyperostotic bone was performed. Orbital and cranial reconstruction was performed in all patients. The follow-up period was 6 months to 12 years (average 5 years). The patients presented with the classic triad of SOM: proptosis (86%), visual impairment (78%), and ocular paresis (20%). A gross-total resection was achieved in 70% of patients with surgery limited by the superior orbital fissure and the cavernous sinus. Proptosis improved in 96% of patients with 87% improvement in visual function. Ocular paresis improved in 68%, although 20% of patients experienced a temporary ocular paresis postoperatively. There were no perioperative deaths or morbidity related to the surgical approach or reconstruction. Ninety-five percent of patients reported an improved functional orbit. There was tumor recurrence in 8% of patients; in one case recurrence was delayed for longer than 11 years. CONCLUSIONS: Sphenoorbital meningiomas are a distinct category of tumors complicated by potentially extensive hyperostosis of the skull base. Successful resection requires extensive intra- and extradural surgery, necessitating drilling of the optic canal and an orbital osteotomy within anatomical limitations. The bone resection requires reconstruction with autograft, allografts, or alloplast for improved orbital function. All aspects of the clinical triad improved. A radical resection can be achieved with low morbidity, providing a significantly improved clinical outcome in the long-term period

The local invasiveness and occasional rapid growth of chordomas, despite optimal treatment, highlight the need to develop ways to predict their biologic behavior. Alterations in adhesion proteins have been shown to participate in proliferation, invasiveness, and metastasis in epithelial tumors. We therefore analyzed the expression of E-cadherin, N-cadherin, as well as their cytosolic binding proteins alpha-catenin, beta-catenin, and gamma-catenin, in 51 paraffin archived and 17 cryopreserved chordoma specimens. In the majority of chordomas, E-cadherin and N-cadherin expression was inversely correlated, whereas beta-catenin and gamma-catenin expression was directly correlated. By multivariate analysis, N-cadherin up-regulation correlated with a diminished recurrence-free survival, and E-cadherin down-regulation strongly correlated with increased probabilities of death as determined by the Kaplan-Meier log-rank test. There was a 3.28-fold increased probability of having a tumor recurrence and a 10.98-fold increased probability of dying when, respectively, N-cadherin was up-regulated and E-cadherin down-regulated. These results suggest that changes in the relative expression of the cadherin-catenin complex reflect chordoma aggressiveness; and that decreased expression of E-cadherin and increased expression of N-cadherin may underlie the transition from a less to a more aggressive tumor phenotype

OBJECTIVE: We discuss and evaluate surgical strategies and results in 42 patients with a variety of tumors involving the anterior and anterolateral foramen magnum and present factors affecting the degree of resection and patient outcomes. We describe our surgical techniques for resection of these tumors via the lateral approach, including consideration for occipital condylar resection and vertebral artery management. METHODS: A retrospective analysis was performed of 42 surgically treated patients with tumors involving the anterior and anterolateral foramen magnum. Patients received treatment between 1991 and 2002; patients' files, operative notes, and pre- and postoperative imaging studies were used for the analysis. RESULTS: The female-to-male ratio was 28:14. Mean patient age was 47 years. Pathological entities comprised 18 meningiomas, 12 chordomas, 3 glomus tumors, 3 schwannomas, and 6 miscellaneous tumors. We mobilized the vertebral artery at the dural entry point in all patients with meningiomas. The vertebral artery was mobilized at the C1 transverse foramen for the majority of extradural tumors. Partial condyle resection was performed in eight meningiomas and five extradural tumors. Complete condyle resection was required in 12 cases, including 9 chordomas, 2 carcinomas, and 1 bone-invading pituitary adenoma. Thirteen patients required occipitocervical fusion after tumor resection. CONCLUSION: In anterior or anterolaterally located foramen magnum tumors, we think the extreme lateral or far lateral approach affords significant advantages. Vertebral artery mobilization and occipital condyle resection may be needed depending on the extent and location of the foramen magnum tumor and its specific pathological characteristics. Tumor invading the occipital condyle or significant condylar resection may cause occipitocervical instability and require fusion

The search for the origin of the commonly held principle in current neurosurgery regarding the resectability of the anterior one third of the superior sagittal sinus unravels the many fascinating developments that occurred in neurosurgery during the early 20th century. All these occurrences can be traced back to, and are uniquely contextualized in, Harvey Cushing's seminal text, Meningiomas, Their Classification, Regional Behaviour, Life History, and Surgical End Results. Written with Louise Eisenhardt and published in 1938, Meningiomas is a monograph of incredible description and detail. The meticulous categorization of meningiomas, their presentation, clinical outcome, and surgical therapies are even further supplemented by Cushing's personal commentary, questions, and recollections. Cushing's genius was evident in his ability not only to make insightful clinical observations, but also to synthesize these ideas within the neurosurgical context of his era. As he says in Meningiomas, 'Thus the pathological curiosity of one day becomes in its proper time a commonplace... most of which are one and the same disorder--had, for their interpretation, to await the advent of the Neurosurgeon.'

OBJECTIVE: Surgical strategies and results for 50 patients with meningiomas involving the optic nerves are discussed and evaluated. Factors affecting the degree of resection and patient outcomes are presented. We emphasize our surgical techniques for resection of these tumors and we discuss the advantages of different approaches, depending on the relationship of the tumor to the optic nerves. METHODS: Data for 50 patients with meningiomas involving the optic nerves who were surgically treated between 1991 and 2002 were reviewed, by using patient files, operative notes, and pre- and postoperative imaging and ophthalmological examination findings. RESULTS: Thirty-one female patients and 19 male patients, with a mean age of 53 years, were treated. Thirty-one patients (62%) underwent complete tumor removal (Simpson Grade 1 or 2), and 19 patients underwent subtotal removal (Grade 4). Factors affecting the grade of resection were tumor size (P = 0.01), location (P = 0.007), and internal carotid artery encasement (P = 0.019). Patients who underwent Grade 1 or 2 resection exhibited a mean tumor size of 3.0 cm, and patients who underwent Grade 4 resection exhibited a mean tumor size of 4.1 cm. Only three patients had residual tumor on the optic nerve; all others had tumor in the cavernous sinus or at the orbital apex or exhibited vascular involvement. Visual outcomes were influenced predominantly by tumor size, preoperative visual function, and optic nerve encasement. CONCLUSION: Meningiomas that involve the optic nerves require special considerations and surgical techniques. Early decompression of the optic nerve within the bony canal allows identification and separation of the tumor from the nerve, permitting removal of the tumor from this area with minimal manipulation of the optic nerve