Faculty Bibliography

BACKGROUND: Tumors at the craniovertebral junction are difficult to remove because of their location and complex anatomic relations. The lateral transcondylar approach is a versatile approach to this area and allows access to a variety of intra- and extradural tumors. The lateral transcondylar approach has been used for a series of chordomas in this location. OBJECTIVE: The nuances of this operation and its effectiveness in this group of patients are presented. METHODS: There were 29 chordomas (1991-2007) in this region treated by one of the authors (CS) that were retrospectively reviewed. The imaging studies and medical records were evaluated. The location and extent of the tumor were defined, and the postoperative images were studied to determine the degree of resection. RESULTS: There were 11 male and 18 female patients; their age range was 7 to 67 years. Headache and neck pain were the predominant presenting symptoms, and hypoglossal nerve palsy was the most common cranial nerve palsy. Twelve patients had previous surgery and 9 had previous radiation. Anterior midline and lateral approaches were used independently or in combination to treat these patients. Dural invasion was found in 27 patients requiring resection of the dura. Surgery was performed in 1 stage in 19 patients, and the tumor resection in the remaining patients was done in 2 stages. The lateral transcondylar approach was used in 19 patients. The occipital condyle was involved in all these patients. Radical tumor resection was achieved in 17 patients. Patients who had complete removal of the occipital condyle required occipitocervical fusion (20 patients) in the immediate postoperative period. CONCLUSION: The lateral transcondylar approach is an effective approach to chordomas in this region. Most of the tumors were large and extended into multiple anatomic compartments. The approach allowed resection of all the involved tissues, intra- and extracranial, and afforded excellent neurovascular control

OBJECTIVE: Patients with partial or complete bilateral vertebral artery occlusion often present with signs and symptoms of transient ischemic attacks or infarction. Advances in phase contrast magnetic resonance imaging have led to noninvasive assessment of volumetric blood flow rates and direction that help in the workup and management of these patients. CLINICAL PRESENTATION: We present the case of a patient with symptoms of vertebrobasilar insufficiency without previous transient ischemic attacks or stroke. Quantitative magnetic resonance angiography (QMRA) demonstrated bilateral vertebral artery occlusion with reversal of flow in the basilar and vertebral arteries to the level of the posterior inferior cerebellar arteries bilaterally. A prominent right posterior communicating artery filled the basilar artery and proximal vertebral arteries. INTERVENTION: The presence of reversal and diminished flow in the basilar and vertebral arteries suggested that occipital artery-to-posterior inferior cerebellar artery bypass would improve posterior circulation, relieve symptoms, and reduce the risk of infarction. Postoperative QMRA and angiography confirmed revascularization, and QMRA confirmed correction of blood flow direction. CONCLUSION: This case illustrates the potential of QMRA as part of a comprehensive cerebrovascular assessment, operative planning, and follow-up of patients with vertebrobasilar insufficiency

We report a young man who presented with atrial fibrillation and was subsequently found to have a markedly elevated serum thyroid stimulating hormone level and a solid, noncalcified intrasellar mass on imaging. The patient was treated with thyroid radioablation and hormone replacement and followed for 7 years, during which time the tumor grew to 4.6 cm. He had no visual disturbances or other hormonal symptoms. At transsphenoidal surgery, a tumor consisting of a pituitary adenoma and adamantinomatous craniopharyngiomalike components was resected. Both components were closely intermingled, but there was no evidence of an intermediate morphologic phenotype. Immunohistochemically, the adenoma was not only positive for beta-thyroid stimulating hormone, alpha subunit, and pituitary transcription factor 1, but also stained for beta-follicle stimulating hormone, steroidogenic factor-1, adrenocorticotropic hormone, and pituitary-restricted transcription factor (Tpit), exhibiting an unusual plurihormonal profile. The craniopharyngiomalike component showed immunoreactivity for steroidogenic factor-1, one of the pituitary transcription factors. This lesion may represent an unusual composite tumor attributable to divergent differentiation of a common precursor. Alternatively, it may be viewed as a pituitary adenoma showing metaplastic change analogous to the development of squamous cell nests of the pars tuberalis from adenohypophyseal endocrine cells

Endovascular and cerebral bypass therapies are rarely used in children. The authors describe the treatment of a partially coiled giant distal vertebral artery (VA)-posterior inferior cerebellar artery (PICA) aneurysm in a child. They performed a side-to-side PICA-PICA anastomosis followed by endovascular VA aneurysm deconstruction with PICA preservation. A healthy 11-year-old boy developed progressive holocephalic headaches over the course of 2 months. Magnetic resonance imaging and magnetic resonance angiography revealed a large right PICA aneurysm causing brainstem compression. In November 2005, 2 Neuroform stents and Guglielmi detachable coils and Matrix were placed in the aneurysm at an outside institution. In 2006, angiography demonstrated aneurysm enlargement from which the PICA originated, coil compaction, and increased mass effect. The patient underwent a PICA-PICA bypass with intraoperative flow measurements followed by endovascular embolization of the aneurysm and parent VA. An angiogram obtained after the procedure demonstrated filling of the right PICA medullary branch through the bypass and obliteration of the aneurysm. The patient remained neurologically intact. Giant aneurysms of the posterior circulation are rare but do occur in children. With the aid of combined surgical and endovascular strategies the authors were able to safely eliminate the aneurysm from circulation with good outcome. Cerebral bypass and endovascular deconstructive therapies can be used safely in children but should be reserved for cases in which direct treatment carries significant risk. Careful surgical and endovascular planning with intraoperative flow assessment is essential for good outcome

OBJECT: Chordomas of the cervical spine are rare tumors. Although en bloc resection has proven to be the ideal procedure in other areas, there is controversy regarding this approach in the cervical spine. The goal in this study was to determine whether piecemeal tumor resection was efficient in the management of chordomas that arise in this location. METHODS: The authors retrospectively reviewed all 74 cases of chordoma treated by their group. Seven patients with isolated cervical chordomas who were treated between October 1992 and January 2006 were identified. There were four male and three female patients, whose ages ranged from 6 to 61 years (mean 34.4 years). Follow-up duration ranged from 7 to 169 months (median 23 months). All cases were managed using a retrocarotid approach with mobilization of the vertebral artery. When the tumor could not be completely resected via the initial anterior approach, a subsequent posterior resection was performed. Tumor resection was intralesional in all cases, and gross-total tumor resection was achieved in six cases. One patient required a second resection 4 months later. In all cases, a posterior stabilization procedure was performed. Five patients underwent anterior fusion (three with fibular allograft and two with iliac crest), whereas two underwent occipitocervical fusion. In two patients with dedifferentiated chordoma metastasis developed, and one of them died 7 months later. The other patient with metastasis died suddenly at home 26 months postsurgery, presumably from aspiration. At the time of this submission, there were no signs of recurrence in five patients. CONCLUSIONS: The authors believe that, in most cases, en bloc resection of cervical chordoma is not feasible. This is due to the tendency of chordomas to involve multiple compartments at the time of diagnosis. In the authors' experience, intralesional radical resection remains an effective surgical approach to this disease entity

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

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

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