OBJECT Chordomas and chondrosarcomas are rare and difficult to treat tumors for which the optimum treatment modality remains controversial. The aim of this study was to evaluate the surgery-related results and complications in a series of patients in whom radical resection was the treatment of choice. METHODS The authors conducted a retrospective analysis of the surgery-related results and complications associated with chordoma and chondrosarcoma in 64 patients of whom 33 (52%) had previously undergone some form of treatment. Total or near-total excision was achieved in 56% and this rate increased to 68% in patients without prior treatment. The main complications were postoperative cerebrospinal fluid leakage, intraoperative arterial injury, and new-onset cranial nerve deficits. Arterial injury occurred only and perioperative death occurred more often in patients who had undergone previous treatment. CONCLUSIONS Analysis of the results provides support for a policy of radical excision of chordomas and chondrosarcomas at the time of first presentation. A higher incidence of procedure-related complications is found in patients who have already undergone surgery and radiotherapy.

BACKGROUND We report the clinical, radiological, and surgical findings of patients with posterior fossa meningiomas surgically treated at our institution over the last 6 years.METHODS We reviewed 161 consecutive cases of posterior fossa meningiomas operated on between April 1993 and April 1999 at The George Washington University Medical Center.RESULTS There were 128 female and 33 male patients (mean age 47 years, range of 10-81 years). Meningiomas were classified as petroclival (110 cases), foramen magnum (21 cases), cerebellar hemispheric, lateral tentorial (14 cases), cerebellopontine angle (9 cases), and jugular foramen (7 cases). Mean tumor equivalent diameter (TED) = (D1XD2XDE)(1/3) was 3.1 cm (range of 0.53-8.95). Head pain (50% of cases) and disturbance of gait (44%) were the most common presenting symptoms, and cranial neuropathies the most common neurological signs on admission. Mean preoperative performance status (Karnofsky scale) was 80.2 (range 40-100). Surgical approaches to these tumors included partial labyrinthectomy petrous apicectomy, fronto-temporal/fronto-temporal orbitozygomatic osteotomy, retrosiginoidal, extreme lateral, transpetrosal, and combined. In 38 cases a staged procedure was performed. Gross-total resection was achieved in 57% of patients, and subtotal/partial in 43%. Surgical mortality was 2.5% and complications were encountered in 41% of patients. Postoperative CSF leak occurred in 22 cases (13.6%). The mean follow-up was 19 months, ranging from 0.2 to 63.6, and the mean performance status of patients with a follow-up of at least 12 months was 77 (range of 40-100). Recurrence or progression of disease was found in 13.7% of cases (follow-up 2 years or more).CONCLUSION Our experience suggests that although posterior fossa meningiomas represent a continuing challenge for contemporary neurosurgeons, such tumors may be completely or subtotally removed with low rate of mortality and acceptable morbidity, allowing most of these patients to achieve a good outcome in a long-term follow-up. (C) 2001 by Elsevier Science Inc.

Carotid and cranial nerve injuries from zone III (high cervical/cranial base) missile injuries are rare and difficult to treat. We have treated five patients with such injuries. We present our management scheme, and compare it to the management of the same injuries in other reports. Five consecutive zone III missile injuries presented to our institution. Trauma assessment by the trauma team, followed by detailed neurological assessment and radiographs (angiogram and computed tomography) were obtained on admission. All patients presented with dysphagia and carotid artery injury with good collateral flow, documented by angiogram. Two patients had facial nerve injury, one had trigeminal nerve injury, one patient presented with tongue weakness, and one patient suffered conductive hearing loss. No patient had evidence of stroke clinically or radiographically. Carotid artery injury was managed with bypass (3 of 5) or ligation (2 of 5). Cranial nerve injuries were documented and treated aggressively with surgery if needed. All patients were discharged to home. Patients presenting with zone III missile injuries should receive an expeditious neurological exam and four-vessel angiogram after initial trauma survey and resuscitation. Bypass of the injured portion of carotid artery is a valid treatment in the hemodynamically stable patient. The unstable patient should undergo ligation to stop hemorrhage and protect against immediate risk for stroke, with the option to bypass later. Cranial nerve injuries should be pursued and aggressively treated to minimize morbidity and prevent mortality.

Objective: There has been ongoing controversy about the optimum treatment modality of acoustic neuroma. Specifically, the question is whether it should be treated by radiosurgery or microsurgery, especially the smaller tumors. The aim of this study is to compare the results of microsurgery and radiosurgery on an equivalent group of patients with acoustic neuromas.Methods: Among a group of 69 acoustic neuromas, operated by the authors over a period of four years (from 1995 to 1999), 41 patients were chosen for the study, fulfilling the following criteria: Tumor Equivalent Diameter [Tumor Equivalent Diameter (TED) = (D(1)x D-2 x D-3)(1/3)] less than or equal to 2.9 cm, not previously operated or irradiated, operated by retrosigmoid approach, no evidence of neurofibromatosis type II, and follow-up period more than 3 months. Published results of radiosurgery, with at least two-year followup, were used to compare.Results: There is no significant difference in terms of hearing preservation or facial nerve function. Complications occurred in both the groups. However, reoperation was done in a few patients treated by radiosurgery, whereas none of the patients treated by microsurgery had recurrence.Conclusion: Radiosurgery is a valuable support, but in most of the cases, surgery is the first line of treatment. In a few selected cases, radiosurgery may be a valuable first line of treatment.

Object. The aim of this study was to describe six variations of the extreme-lateral craniocervical approach, their application, and treatment results. Methods. During a 4-year period 69 patients underwent surgery in which six variations of the extreme-lateral craniocervical approach were performed. The variations included: the transfacetal approach (TFA), performed to treat four lesions in the upper cervical spine anterior or anterolateral to the spinal cord; the retrocondylar approach, to treat five intradural lesions located anterolateral to the medulla oblongata and six vascular lesions to expose the extradural segment of the vertebral artery (VA); the partial transcondylar approach (PTCA), to treat 18 intradural lesions located anterior to the medulla oblongata; the complete transcondylar approach (CTCA), to treat 13 extradural lesions that involved the lower clivus and anterior upper cervical spine; the extreme-lateral transjugular approach, to treat 14 jugular foramen tumors; and the transtubercular approach with or without division of the sigmoid sinus, to treat complex VA and vertebrobasilar junction aneurysms. An anatomical prosection was performed to study the surgical exposure of each of the six variations of the extreme-lateral craniocervical approach. Total removal was achieved in 35 (69%) of the patients with tumor; subtotal resection was achieved in 16 (31%) of those patients. In the 12 patients with VA aneurysms, seven underwent clipping, three underwent trapping and a vein graft bypass procedure, and two underwent trapping without the use of a bypass procedure. In five other patients, different cystic, inflammatory, and other vascular lesions were successfully treated. Fifty percent of the patients who underwent surgery via the TFA, 83% via the of the CTCA, and 11% via the PTCA required an occipitocervical fusion procedure. The mean Karnofsky Performance Scale score was 74.7 preoperatively and 76.4 postoperatively. Major complications were hydrocephalus (nine patients), cerebrospinal fluid leakage (seven patients), worsened cranial nerve function (seven patients), vertebrobasilar vasospasm (one patient), and sigmoid sinus thrombosis (one patient). Conclusions. To treat lesions in the region of the foramen magnum and surrounding areas, the approach should be tailored to each specific lesion to provide the needed exposure without unnecessary operative steps.

The petrolingual ligament is the posteroinferior attachment of the lateral wall of the cavernous sinus, where the internal carotid artery enters the cavernous sinus. The petrous segment of the internal carotid artery finishes and the cavernous segment begins at the superior margin of this ligament. The ligament is surgically important due to its identification as a landmark for dissection of the internal carotid artery during the approaches to posterolateral intracavernous and extracavernous lesions. It can be well exposed after mobilization of the gasserian ganglion, or after the trigeminal root and ganglion have been split along the junction of V2 and V3 (the transtrigeminal approach). The petrolingual ligament was studied in five cadaveric head specimens from ten sides. The size of the ligament was measured, and its anatomical, clinical and surgical importance is discussed.

All patients undergoing neurological surgery are at risk for serious complications. Ischaemic damage presenting with hemiparesis or speech difficulties occurs in up to 6% of patients undergoing cerebral bypass procedures and other complicated neurosurgical procedures. Currently available methods for detection of such damage include the use of somatosensory evoked potentials (SSEPs) and electro-encephalography (EEG). Unfortunately, these techniques have false positives and may remain normal in the presence of severe focal neurological deficits. Early detection of potential deficits may prevent or minimize damage through a change in operative or anaesthetic strategy. With the availability of several potential neuroprotective compounds, it is also possible to treat patients at risk of developing ischaemic complications if the individuals are identified early. The excitatory neurotransmitter glutamate is not only a metabolic product, but is also thought to promote ischaemia induced cell injury if released into the extracellular space. It may be a significant parameter for ischaemic brain metabolism.

The management of acoustic neuromas has evolved significantly over the course of this century. Harvey Cushing introduced the modern era of surgery for acoustic neuromas by reducing the mortality rates from ∼50 to ∼10%. In 1906 he performed his first operation for an acoustic neuroma by using a bilateral suboccipital craniectomy with intracapsular subtotal removal of the tumor. Dandy in 1925 reported five cases with complete resection and no mortality. His technique for unilateral suboccipital exposure, internal decompression, unroofing of the internal acoustic meatus, and total removal of the tumor remains the basis for our modern suboccipital approach to acoustic neuromas (1). The next major advance in the treatment of acoustic neuromas came in 1964 when House introduced the operating microscope for the translabyrinthine removal of these tumors. Rand and Kurze in 1965 also employed the operating microscope for the transmeatal posterior fossa approach (1). The development of microsurgical techniques and subsequent technologic advances such as computed tomography, magnetic resonance imaging, intraoperative brainstem auditory evoked responses, and cranial nerve monitoring have further improved the results obtained in the surgical management of acoustic neuromas in the past quarter century. The advances in technology were not limited to the microsurgical management of acoustic neuromas. In 1969, Leksell introduced the technique of gamma knife radiosurgery for acoustic neuromas (2,3). He used a multiple-source gamma radiation unit together with stereotactic planning to conform a radiation dose to these tumors. Since then, the development of high-resolution neuroimaging with multiplanar capability and improvements in computer technology have allowed radiosurgeons to calculate complex dose patterns for irregularly shaped tumors. There are now >42 gamma knife units operating throughout the world, and many more linear accelerators (LINACs) adapted for use in delivering focused-beam stereotactic radiation (2,4-6). As both microsurgery and radiosurgery are widely used in acoustic neuroma treatment, it is paramount to define the role of each technique in the treatment of acoustic neuromas. We have gathered the results of various microsurgical and radiosurgical series and analyzed the advantages and disadvantages of each technique in an attempt to clarify the controversies that have arisen in this field. It is important to first define the therapeutic goals of both treatment modalities in relation to acoustic neuromas. The goal of microsurgery is complete tumor removal with preservation of neurologic function (7,8). The goal of radiosurgery is control of tumor growth (defined as the absence of tumor growth or a reduction in tumor volume) with preservation of neurologic function (2,5,6,9,10). Radiosurgeons believe that achieving tumor growth control is equivalent to achieving a tumor cure (2).

The outcomes of 114 patients with meningiomas operated at the University of Pittsburgh were analyzed. Cerebrospinal fluid leakage was the most frequent complication, observed in 25 patients (21%). Complications were more frequent in patients who had recurrent (previously operated) tumors and patients with extensive tumors. Our current analysis also indicates that patients with prior radio-therapy (usually external beam) have unacceptably high complication rates after microsurgery. Early results indicate that regrowth rates are much higher in patients with incomplete resection (20%) than those with gross total excision (5%). Of the 114 patients, 108 returned to independent living and/or their previous occupation.

A system of analysis addressing predictors of management outcomes in Cranial Base Surgery has yet to be published. We therefore report data on seventy-nine consecutive patients undergoing surgery for tumors involving the cranial base, excluding patients with the diagnosis of pituitary microadenoma. Outcomes were defined prospectively in terms of completeness of tumor resection, complications of treatment with emphasis on neurological morbidity, and return to work or independent living. Also, preoperative features are analyzed as influencing cost of treatment, estimated in terms of the number of surgical procedures required, duration of hospital and Intensive Care Unit stay, and time taken to return to work. Preliminary analysis of data reveals that severe brainstem compression, large tumor size (average diameter > 3 cm), high cavernous sinus grade, and tumor encasement of major cerebral arteries are associated with incomplete tumor resection (p < 0.05). Patient age greater than 65, preoperative Karnofsky Performance Score (KPS) less than 80, and severe brainstem compression are associated with increased risk of stroke (p < 0.05). Age greater than 65 and preoperative KPS less than 80 are associated with an increased length of stay (p < 0.05). Other untoward events did not occur with sufficient frequency to reach statistical significance. A model of outcomes analysis in Cranial Base Surgery is proposed utilizing a database to incorporate a group of non-operated patients and include quality of life measurements in long-term patient follow-up.

An extreme lateral transcondylar or extreme lateral transfacetal surgical approach was used to treat 22 patients with complex lesions over a 22-month period. The lesions included basilar invagination with vertebral artery pathology, giant aneurysm or arteriovenous fistula of the vertebral artery, meningioma, chordoma, chondrosarcoma, and paraganglioma. The approach was used alone or in combination with a presigmoid petrosal or subtemporal-infratemporal approach. Refinements of the operative technique, treatment strategies for complex lesions, and the avoidance of complications are discussed.Complications included cerebrospinal fluid leakage, meningitis, pseudomeningocele, hemiparesis or quadriparesis, lower cranial nerve deficits, and vertebral artery injury requiring repair. With treatment, major neurological deficits resolved completely in three patients and partially in two. There was no operative mortality, but four patients died during the follow-up period. For the 18 surviving patients, the mean preoperative and postoperative Karnofsky scores were 81 and 93, respectively. For the four who died, the mean preoperative Karnofsky score was 73 and the mean postoperative score was 63.

Patients with cranial base tumors often have impairment in visual function, either due to the pathologic process itself or as a result of surgical treatment of the lesion. We conducted a pilot study in which we performed ophthalmologic evaluations on patients before and after cranial base surgery. The results of the study were used to develop a protocol and reporting form for longitudinal assessment of visual function in these patients. Use of the protocol and reporting form for the past 2(1/2) years has shown that they are easy for physicians to use and that the results provide a representative evaluation of the patient's ability to function visually in everyday life. The authors propose implementation of the protocol and reporting form as a means of collecting data for further research into visual function in patients with cranial base tumors.

A FORTY-ONE-YEAR-OLD MAN with a cavernous hemangioma of the right cavernous sinus underwent a preoperative cerebral angiogram and a balloon occlusion test of the internal carotid artery. During the operation to remove the cavernous sinus lesion, the ipsilateral electroencephalogram was found to be abnormal. An embolic occlusion of the M2 and M3 segments of the middle cerebral artery (MCA) was discovered. A platelet and thromboembolus was removed via multiple incisions, and flow was restored. The cavernous sinus lesion was removed uneventfully. At the end of the operation, the MCA was found to be reclotted. Flow was eventually restored by replacing the M2 segment of the MCA with a 2-cm saphenous vein graft. The patient recovered without any deficits of brain function and with transient deficits of Cranial Nerves III and VI. Computed tomography revealed infarcts in the temporal and parietal areas. When MCA embolectomy is unsuccessful, vein graft replacement should be considered to restore flow and to avoid major neurological deficits.

The improvement in surgical techniques and the experience gained in treatment of skull base tumors have stimulated more aggressive management of larger lesions. Patients presenting with limited preoperative deficits have challenged the surgeon to design the surgical approach so as to minimize postoperative morbidity and preserve function. Tumors of the middle fossa and clivus with extension into the posterior fossa are usually approached by a combined subtemporal, transtentorial, transpetrous approach. In patients with preoperative hearing, the surgical exposure is often limited by the labyrinthine portion of the otic capsule. The technique of partial labyrinthectomy, removing the posterior and/or superior semicircular canals, maximizes exposure with preservation of hearing. This report details our experience with the partial labyrinthectomy approach for 14 patients with large skull base lesions. All patients had hearing preserved despite sacrifice of one or two of the semicircular canals. Bone pure-tone averages and speech discrimination scores were maintained near their preoperative levels. The indications, benefits, techniques, and hearing results of this approach are reviewed.