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PURPOSE Meningiomas are the most frequent primary intracranial tumors. Patient outcome varies widely from benign to highly aggressive, ultimately fatal courses. Reliable identification of risk of progression for individual patients is of pivotal importance. However, only biomarkers for highly aggressive tumors are established ( CDKN2A/B and TERT), whereas no molecularly based stratification exists for the broad spectrum of patients with low- and intermediate-risk meningioma. METHODS DNA methylation data and copy-number information were generated for 3,031 meningiomas (2,868 patients), and mutation data for 858 samples. DNA methylation subgroups, copy-number variations (CNVs), mutations, and WHO grading were analyzed. Prediction power for outcome was assessed in a retrospective cohort of 514 patients, validated on a retrospective cohort of 184, and on a prospective cohort of 287 multicenter cases. RESULTS Both CNV- and methylation family–based subgrouping independently resulted in increased prediction accuracy of risk of recurrence compared with the WHO classification (c-indexes WHO 2016, CNV, and methylation family 0.699, 0.706, and 0.721, respectively). Merging all risk stratification approaches into an integrated molecular-morphologic score resulted in further substantial increase in accuracy (c-index 0.744). This integrated score consistently provided superior accuracy in all three cohorts, significantly outperforming WHO grading (c-index difference P = .005). Besides the overall stratification advantage, the integrated score separates more precisely for risk of progression at the diagnostically challenging interface of WHO grade 1 and grade 2 tumors (hazard ratio 4.34 [2.48-7.57] and 3.34 [1.28-8.72] retrospective and prospective validation cohorts, respectively). CONCLUSION Merging these layers of histologic and molecular data into an integrated, three-tiered score significantly improves the precision in meningioma stratification. Implementation into diagnostic routine informs clinical decision making for patients with meningioma on the basis of robust outcome prediction.

PURPOSE Meningiomas are the most frequent primary intracranial tumors. Patient outcome varies widely from cases with benign to highly aggressive, ultimately fatal courses. Reliable identification of risk of progression for the individual patient is of pivotal importance in clinical management. However, only biomarkers for highly aggressive tumors are established at present (CDKN2A/B and TERT), while no molecularly-based stratification exists for the broad spectrum of low- and intermediate-risk meningioma patients. PATIENTS AND METHODS DNA methylation data and copy-number information were generated for 3,031 meningiomas of 2,868 individual patients, with mutation data for 858 samples. DNA methylation subgroups, copy-number variations (CNV), mutations and WHO grading were comparatively analyzed. Prediction power for outcome of these parameters was assessed in an initial retrospective cohort of 514 patients, and validated on a retrospective cohort of 184, and on a prospective cohort of 287 multi-center cases, respectively. RESULTS Both CNV and methylation family- (MF)-based subgrouping independently resulted in an increase in prediction accuracy of risk of recurrence compared to the WHO classification (c-indexes WHO 2016, CNV, and MF 0.699, 0.706 and 0.721, respectively). Merging all independently powerful risk stratification approaches into an integrated molecular-morphological score resulted in a further, substantial increase in accuracy (c-index 0.744). This integrated score consistently provided superior accuracy in all three cohorts, significantly outperforming WHO grading (c-index difference p=0.005). Besides the overall stratification advantage, the integrated score separates more precisely for risk of progression at the diagnostically challenging interface of WHO grade 1 and grade 2 tumors (HR 4.56 [2.97;7.00], 4.34 [2.48;7.57] and 3.34 [1.28; 8.72] for discovery, retrospective, and prospective validation cohort, respectively). CONCLUSIONS Merging these layers of histological and molecular data into an integrated, three-tiered score significantly improves the precision in meningioma stratification. Implementation into diagnostic routine informs clinical decision-making for meningioma patients on the basis of robust outcome prediction.

Objective Pituitary carcinoma is a rare tumor, defined as a tumor of adenohypophyseal cells with systemic or craniospinal metastasis. We present a case of a growth hormone (GH)-secreting pituitary carcinoma with a review of literature to better characterize this disease. Design Case report and literature review of 25 cases of GH-secreting pituitary carcinomas Results The age of diagnosis of GH-secreting carcinomas ranged 24–69 years old with a mean age of 44.4 with 52% of cases present in females. Mean latency period between diagnosis of acromegaly and transition to pituitary carcinoma was 11.4 years with mean survival being 3.4 years. Conclusion Growth hormone (GH)-secreting pituitary carcinomas are rare and hard to distinguish from aggressive pituitary adenomas. From review of literature, treatment options include debulking surgery, radiotherapy, or chemotherapy with dismal outcomes. There are no diagnostic markers or features which can predict metastatic progression of these tumors. Future studies with genomic landscapes and relevant tumor markers are needed to identify pituitary tumors most likely to metastasize.

The cavernous sinus is a complex structure susceptible to a wide variety of vascular, neoplastic and inflammatory pathologies. Vascular pathologies include ICA aneurysms, carotid-cavernous fistulas, cavernous sinus thrombosis, and cavernous hemangioma. Neoplasms that involve the cavernous sinus include pituitary adenoma, meningioma, schwannoma, lymphoma, perineural tumor spread, metastases, and direct tumor invasion. Infectious and inflammatory diseases include Tolosa-Hunt syndrome, sarcoidosis, granulomatosis with polyangiitis, IgG-4 related disease and invasive fungal infections. In this article, we review the clinical and imaging findings of a number of pathologies involving the cavernous sinus, focusing on key features that can narrow the differential diagnosis and, in some cases, support a particular diagnosis.

Epigenetic patterns on the level of DNA methylation have already shown to separate clinically relevant subgroups of meningiomas. Based on a reference set (Sahm et al., Lancet Oncol 2017), an epigenetic meningioma classifier employing DNA methylation patterns is made available through molecularneurpathology.org. We now set out to identify prognostic implications of epigenetic modification on the proteome level, particularly modifications of histones. First focus was on H3K27 trimethylation (H3K27me3). H3K27me3 was assessed by immunohistochemistry on 232 meningiomas. In 194 cases, trimethylation was detected in tumor cells. In 25 cases, staining was limited to vessels while all tumor cells were negative. Finally, 13 cases yielded equivocal staining patterns. Reduced abundance of H3K27me3 in cases with staining limited to vessels was confirmed by mass spectrometry on a subset of cases. Lack of staining for H3K27me3 in all tumor cells was significantly associated with more rapid progression (p=0.009). In line, H3K27me3 negative cases were associated with a DNA methylation pattern of the more aggressive types among the recently introduced DNA methylation groups. Also, NF2 and SUFU mutations were enriched among cases with lack of H3K27me3 in tumor cells (p

Background Hemangiopericytomas (HPCs) are rare vascular tumors that resemble meningiomas on imaging and have a high rate of local recurrence and metastases. There remains a paucity of data to guide management decisions of intraspinal dissemination of HPCs in the literature, and none specifically related to anaplastic HPCs. Case Description We report a case of a 34-year-old woman with locally and distantly recurrent anaplastic HPC (World Health Organization grade III). She initially presented with tinnitus in her right ear. A well-circumscribed, contrast-enhancing lesion was identified in the right cerebellopontine angle. Treatment consisted of subtotal resection and postoperative radiation therapy (RT) to a dose of 60 Gy in 30 fractions. After a 3-year disease-free interval, 7 lesions recurred intra- and extracranially. The extracranial lesions were drop metastases of the original HPC through the cerebrospinal fluid into the spinal canal. Of note, fluorodeoxyglucose positron emission tomography (PET)/computed tomography scan was not sensitive enough to detect these new lesions. The intracranial recurrence was on the edge of the prior radiotherapy field, representing a marginal failure having received less than 50 Gy. The intracranial recurrences were treated with salvage gamma knife stereotactic radiosurgery (SRS) with local control. She underwent intradural extramedullary hemilaminectomy of a thoracic spine metastasis followed by fractionated proton beam therapy (PBT) with a boost to unresected lesions. Within a few months of PBT, she became pregnant. Pregnancy did not affect recurrence or ameliorate tumor growth. Conclusions This case report discusses the role genetics, adjuvant RT, SRS, magnetic resonance imaging, and PET scan played in this unique clinical scenario of anaplastic HPC.

e14044Background: Up to 20% of meningiomas behave aggressively with high recurrence rates and reduced survival. There is a lack of biomarkers predicting the risk of an unfavorable clinical course a...

✓ The extended frontal approach is a modification of the transbasal approach of Derome. The addition of a bilateral orbitofrontal or orbitofrontoethmoidal osteotomy improves the exposure of midline lesions of the anterior, middle, and posterior skull base, while minimizing the need for frontal lobe retraction. The authors present a 5-year experience with 49 patients operated on via the extended frontal approach. In seven patients, the extended frontal approach was used alone; in the remaining 42, it was combined with other skull base approaches. Highly malignant tumors were removed en bloc, whereas benign tumors and low-grade malignancies were removed either en bloc or piecemeal. Reconstruction was usually performed using fascia lata, a pericranial flap, and/or autologous fat. A temporalis muscle flap or a distant microvascular free flap was required for some patients. One patient died 1 month postoperatively due to superior mesenteric artery thrombosis. Three patients had postoperative infections, two had cerebrospinal fluid leaks requiring reoperation, and four had brain contusions or hematomas. All but two patients recovered to their preoperative functional level. After an average follow-up period of 26 months (range 6 to 56 months), 64% of patients with benign lesions, 64% of patients with low-grade malignancies, and 44% of patients with high-grade lesions were alive with no evidence of disease.

Craniofacial disassembly now plays a major role in the manage-ment of tumors that invade the skull base. The chief advantage of this technique is the greatly improved operative exposure it provides, allowing the surgeon to resect such tumors more completely and with an added margin of safety. Microneurosurgical advances have made it possible to preserve cranial nerve function in many cases, and modem reconstructive methods employing vascularized flaps have helped to reduce postoperative complications and deformity. Through the combination of craniofacial techniques and oncologic principles, the outlook for patients with skull base tumors is improving.

The main difficulty in dealing with intradural lesions located ventrally in the region of the craniovertebral junction (CVJ) is related to their relative inaccessibility. Posterolateral approaches involve some manipulation of the brain stem and provide limited access because of the necessity of working between the cranial nerves. Even then, the view of the ventral midline and across is limited. The transoral approach, which has been widely used for the management of extradural lesions in this area, is also useful for the treatment of intradural lesions. It provides an unimpeded although somewhat restricted, view of the ventral aspect of the CVJ without the need for brain retraction. The cranial nerves and vertebral arteries are not interposed between the surgeon and the lesion. The risks of cerebrospinal fluid leakage and infection are greatly diminished by the use of fibrin adhesive and prolonged diversion of the cerebrospinal fluid. The use of this approach, together with its technical difficulties and results, in the management of seven purely intradural lesions located ventrally at the CVJ, is discussed.

The complexity of cranial base surgery is a reflection of skull base anatomy as well as technical demands for maximum visualization, control of essential structures, adequate tumor resection and/or reconstruction. Facial translocation has been developed as a new approach to cranial base. It consists of extensive modular facial disassembly which includes displacement of composite facial soft tissue flap and craniofacial skeleton. It creates surgical field with epicenter in nasopharynx and infratemporal fossa allowing easy expansion into sphenoid bone and cranial fossae as well as craniovertebral junction. Recon-struction is functional and esthetic. Versatility of this approach permits expansion into neighboring craniofacial regions. During a 14-month period (11/88-12/89), this facial translocation approach to cranial base was utilized in 20 patients. The approach provided excellent visualization of the involved cranial base permitting oncological as well as reconstructive procedures. All patients healed primarily. Two patients were reoperated on at 4 and 6 months postoperatively; one for a bone graft infection and the other for tumor recurrence. The facial translocation approach offers favorable exposure of the critical zones of cranial base resulting in increased surgical safety and benefit of cranial base surgery.

✓ The subtemporal and preauricular infratemporal operative technique is an approach to the skull base through the anterior portion of the petrous temporal bone and is used for the removal of predominantly extradural tumors in this region. The present study, based on dissection of human cadavers, describes the use of this approach for the management of intradural lesions in the region of the clivus. Its main advantages include avoidance of brain retraction, the use of an extrapharyngeal route, and exposure of the ventral aspect of the pons and medulla and related structures caudal to the trigeminal root. This approach can easily be combined with an intradural subtemporal approach to provide additional exposure of the superior clivus rostral to the trigeminal root. Combining the two approaches provides direct access to the ventral surface of the entire brain stem from the dorsum sellae to the hypoglossal foramina. Five patients with lesions in the clivus and petrous apex have been operated on via this approach. Details of the anatomical aspects of the approach and its applications are presented.

A multidisciplinary approach to the treatment of malignant cranial base tumors has resulted in improved resections with less morbidity and a greater potential for cure. An improved understanding of the complex anatomy has allowed the development of new surgical approaches and improved methods of reconstruction. The authors' experience with the treatment of malignant neoplasms of the cranial base is reviewed, with emphasis on biologic behavior of this diverse group of neoplasms.

OBJECTIVE: The purpose of this study was to analyze the available clinical data on postoperative intracerebral hemorrhages that occur in locations remote from the sites of craniotomy. METHODS: The findings of 37 cases of postoperative intracerebral hemorrhages occurring remote from the craniotomy sites were reviewed (5 from our records and 32 from the literature). RESULTS: Remote postoperative intracerebral hemorrhages presented within the first few hours postoperatively in 78% of the patients and were not related to the types of lesions for which the craniotomies were performed. Supratentorial procedures that produced infratentorial hemorrhages involved operations in the deep sylvian fissure and paraclinoid region in 81% of the patients and hemorrhages in the cerebellar vermis in 67% of the patients. Infratentorial procedures that produced supratentorial hemorrhages were performed with the patient in the sitting position for 87% of the patients. The remote supratentorial hemorrhages that occurred were superficial and lobar in 84% of the patients, as opposed to deep and basal ganglionic, which are classic locations for hypertensive hemorrhages. Remote intracerebral hemorrhages occurring after craniotomies were not associated with hypertension, coagulopathy, cerebrospinal fluid drainage, or underlying occult lesions. These hemorrhages commonly led to significant complications; 5 of 37 patients(14%) were left severely disabled, and 12 of 37 patients (32%) died. CONCLUSIONS: Remote intracerebral hemorrhage is a rare complication of craniotomy with significant morbidity and mortality. Such hemorrhages likely develop at or soon after surgery, tend to occur preferentially in certain locations, and can be related to the craniotomy site, operative positioning, and nonspecific mechanical factors. They do not seem to be related to hypertension, coagulopathy, cerebrospinal fluid drainage, or underlying pathological abnormalities.

CAVERNOUS SINUS SURGERY has been performed increasingly in the last 2 decades because of new knowledge and technologies. With increasing international expertise in cavernous sinus surgery, the results must be analyzed critically to search for accurate prognosticators of outcome. We performed a retrospective review of 124 patients (40 male, 84 female; mean age, 45 years) who underwent cavernous sinus surgery for benign tumors from 1983 to 1992. Sixty-five percent had tumors encasing the internal carotid artery. Mean follow-up was 29 months (median, 26 mo). Gross total or near-total resection was possible in 80%. Patients with neurilemomas, angiofibromas, epidermoids, chondroblastomas, and hemangiomas were more likely to have total or near-total resection (100% versus 75%, P0.025). Disabling complications (five cerebral infarctions, two meningitis, and one hydrocephalus with chiasmal prolapse) occurred only in patients with meningiomas or pituitary adenomas. On follow-up, excellent/good binocular vision was achieved in 53% of patients entering surgery with excellent/good function versus 25% who entered surgery with fair/poor binocular vision (P0.025). Ninety-three percent of patients had a Karnofsky scoreor = 70 on follow-up. There were a total of 12 recurrences (10%), 6 in patients with meningiomas, 2 in patients with angiofibromas, 2 in patients with craniopharyngiomas, 1 in a patient with a pituitary adenoma, and 1 in a patient with an osteoblastoma. Patients with tumor growth or neurological symptoms indicative of progressive cavernous sinus involvement should undergo cavernous sinus exploration. This surgery has acceptable morbidity and mortality and, if the tumor can be removed easily, the surgeon should try to perform radical tumor resection. To avoid major complications, the surgeon must exercise utmost care to preserve the neurovascular structures of the cavernous sinus, with special attention to tumors that extend into the petroclival region. Better results from surgery can be expected in those patients with neurilemomas, hemangiomas, or epidermoids than in patients with meningiomas, craniopharyngiomas, or pituitary adenomas. Good functional outcome can be expected, particularly if the patient's preoperative clinical status is good. Particular attention must be paid to the reconstruction of anatomic barriers in order to prevent cerebrospinal fluid leakage and subsequent meningitis.

During the last 9 years, 31 patients with chordomas (20 cases) and chondrosarcomas (11 cases) involving the cavernous sinus have been treated using an aggressive surgical approach. On the basis of postoperative magnetic resonance imaging (MRI), 17 patients were considered to have undergone total removal, whereas in the remaining 14 cases the tumor was either subtotally or partially removed. Surgical complications were most commonly encountered among patients who had undergone previous operations. One patient died 3 months after the operation as a result of pulmonary embolism. Significant disability occurred in one patient because of thalamic perforator occlusion and hemorrhage. Recovery of extraocular muscle function was gratifying, and correlated to the preoperative functional level. After a median follow-up of 24 months, three recurrences (21%) occurred among the 14 patients who had undergone incomplete removal. No recurrence was observed among the 17 patients with total resection. This experience shows that gross radical removal of chordomas and chondrosarcomas involving the cavernous sinus can be accomplished with an acceptable surgical morbidity. However, much longer follow-up will be required to determine whether such aggressive surgical treatment results in cure or long-term control of these neoplasms.

The purpose of this study was to determine if it is possible to predict complications of surgery on cavernous sinus meningiomas on the basis of preoperative MR and CT findings.We retrospectively reviewed the CT, MR, and postoperative clinical findings in 65 consecutive patients with pathologically proved cavernous sinus meningiomas who had surgery during the period 1985-1991. Tumors were categorized on the basis of their relationship to the cavernous carotid artery. The presence of tumor in three anatomic sites (the sella, the sphenoid sinus, and the orbital apex) was also correlated with surgical complications.Category 1 tumors, which do not completely encircle the cavernous carotid artery, were dissected without injury, sacrifice, or grafting of the artery in 91% of cases. Category 2 lesions completely encircle the artery but do not narrow its lumen; they could be dissected from the cavernous carotid artery without arterial injury in 61% of cases, but imaging failed to discriminate differences within this group. Category 3 lesions, which completely encircle and narrow the cavernous carotid artery, are usually difficult to dissect free from the artery. The categories also correlated with recovery of extraocular motility; 84% of category 1 lesions compared with only 36% of category 2 or 3 lesions will recover to good or excellent extraocular motility after cavernous sinus surgery. Tumor involvement of the sella, orbital apex, and sphenoid sinus correlated with postoperative endocrine dysfunction, decreased visual acuity, and CSF leak, respectively.Imaging studies can frequently predict the difficulty of resecting cavernous sinus meningiomas from the cavernous carotid artery and the likelihood of permanent loss of extraocular motility after surgery on these lesions. This information is helpful in appropriate preoperative planning and in providing information to patients about to undergo such surgery.

This study reviewed 124 patients who required facial nerve manipulation during cranial base surgery. Most of them underwent only nerve displacement or selective transection for improved surgical access to the cranial base (70 and 34, respectively). Fourteen patients had the facial nerve resected for oncologic reasons and repaired with primary nerve grafting. Most patients regained quite satisfactory facial function with quality correlating with the degree of nerve injury. Six patients had facial nerve resected as part of oncologic palliation and had the facial deficit rehabilitated with regional tissue. A correlation between preoperative facial nerve weakness and the quality of nerve graft function was not found. An oncologic correlation, however, is suggested (patients with preoperative weakness had less favorable prognosis). Overall, patients who require facial nerve resection for oncologic reasons do not do as well as those with normal preoperative function.

During the last 7 years, approximately 170 neoplasms, and 35 vascular lesions involving the cavernous sinus were treated by the first two authors. During the treatment of such lesions, the direct vein graft reconstruction of the internal carotid artery from the petrous to the supraclinoid or infraclinoid ICA was performed in 23 patients. Graft occlusion occurred in 3 patients and in one of these, it was successfully salvaged by placing a long venous graft from the extracranial ICA to the M3 segment of the middle cerebral artery. The latter 3 patients were neurologically normal. One patient with significant athero-sclerotic disease suffered the dissection of the distal internal carotid artery with the graft being patent. The dissection presumably occurred because of the separation of the intima and the media and an improper suturing technique. This patient eventually died. Two patients with severely compromised collateral circulation suffered minor strokes due to the temporary occlssion of the ICA. This has been avoided in the more recent patients by the adoption of brain protection techniques such as moderate hypothermia, induced hypertension, and barbiturate coma. Low dose heparin therapy during grafting and high dose intravenous steroids prior to the grafting also appear to be beneficial. Direct vein graft reconstruction of the intracavernous carotid artery is a valuable tool during the management of cavernous sinus lesions. The advantages and disadvantages of this technique as well as the pros and cons of other revascularization techniques will be discussed. During microsurgical removal of cavernous sinus lesions, the cranial nerves III-VI were reconstructed by direct resuture or by nerve grafting in 16 patients. In the majority of these patients, recovery of cranial nerve function was observed, which was very encouraging. Cranial nerve reconstruction should be attempted whenever the nerves are sacrificed in a patient who has a fair to excellent eye function preoperatively or whenever inadvertent injury to such nerves occurs during cavernous sinus surgery.

Responses from the dorsal column nuclei (DCN) in the rat to stimulation of the upper limbs (median nerve) and lower limbs (sciatic nerve) showed a difference in the wave forms of the two responses. These results support results of earlier studies in the cat, monkey, and man that showed that only slow-conducting cutaneous afferents from the lower limbs travel in the dorsal column, while all afferents from the upper limbs travel in the dorsal column and synapse in the DCN. A comparison between the response from the DCN and that from the vertex to stimulation of the upper limbs showed correspondence between short-latency peaks, while no clear earlier waves could be discerned in the response from the vertex to stimulation of the lower limbs. Even when the dorsal column was transected on one side, the correspondence between the early peaks in the scalp and the DCN responses to stimulation of the upper limbs was maintained. The effect of the dorsal column lesion on the response recorded from the surface of the DCN to stimulation of the sciatic nerve was mainly a reduction in the number of peaks. Transection at the midbrain level resulted in elimination of the long-latency response in the scalp recording, but the initial negative peak was maintained, which corresponded to the initial negative peak of the DCN response to stimulation of the upper limbs.

The role of perioperative antibiotic prophylaxis was investigated in 95 patients undergoing 100 clean-contaminated cranial base surgeries. A variety of antibiotic regimens were employed. Potential risk factors for local infection were analyzed. Seven patients (7%) developed infections at the surgical site (meningitis, intracranial abscess, cellulitis/abscess, and osteomyelitis). Antibiotic prophylaxis for 24 hours or less was associated with a significantly increased risk of infection (p less than 0.04). Prolonged antibiotic prophylaxis (greater than 48 hours) was not more efficacious than prophylaxis for 48 hours. The surgical approach, type of reconstruction, duration of surgery, and use of drains were not significantly correlated with wound infection. The risk of intracranial infection following cranial base surgery is low despite the presence of bacterial contamination intraoperatively. Broad-spectrum coverage of gram-positive and gram-negative organisms for at least 48 hours is recommended. Attention to surgical technique is important in preventing infectious complications.

Treatment of some tumors and aneurysms of the skull base may require internal carotid artery (ICA) sacrifice. Preoperatively to determine the dependence of the cerebral blood flow on a particular vessel, we perform a balloon test occlusion (BTO) by temporarily occluding the vessel in an awake patient. During occlusion, clinical evaluations and cerebral blood flow measurements are assessed. We have performed 300 BTOs. Eleven patients (3.7%) have had complications. Six (2%) were asymptomatic dissections. Five (1.7%) had neurologic deficits that persisted beyond the test period. Of these five, one was back to baseline in less than 24 hours, one recovered completely in a week, and one (0.33%) had a minimal but persistent dysphasia. These latter three cases are unexplained but might have resulted from unrecognized dissections or embolic events. Finally, one patient with a persistent deficit required energency surgery for reasons unrelated to the BTO and was therefore difficult to assess, and one required emergency middle cerebral artery embolectomy and repair of the dissection. The preoperative knowledge of carotid dependence in cases in which the ICA is at risk is essential, since vascular grafts or alternative surgical approaches are necessary in patients unable to tolerate carotid sacrifice. Since approximately 15 to 20% of the population falls into this category, a preoperative BTO appears justified.

Nasopharynx, clivus, and cavernous sinus are difficult regions of the cranial base in which to perform oncologic surgery. We have developed an approach to this area by using facial soft tissue translocation and craniofacial osteotomies. Surgical field obtained at the skull base can extend from the contralateral eustachian tube to ipsilateral geniculate ganglion. It includes the nasopharynx, clivus, sphenoid, and cavernous sinus, as well as the entire infratemporal fossa and superior orbital fissure. Our experience with this technique in 12 patients is reported. All patients healed primarily.

✓ Saphenous vein graft reconstruction was performed from the petrous to the supraclinoid internal carotid artery (ICA) to replace the cavernous ICA in six patients during direct intracavernous operations. Four of these patients had intracavernous neoplasms with invasion of the ICA and two had intracavernous ICA aneurysms that could not be clipped or occluded with intraluminal balloons. All but one patient had evidence of poor collateral flow reserve in a balloon occlusion test of the ICA. The superficial temporal artery was not present in four patients, was minuscule in one, and was damaged during the initial dissection in another, making it unsuitable for superficial temporal-to-middle cerebral artery branch anastomosis. Blood flow within the graft could not be established intraoperatively in one patient (who had excellent collateral circulation) due to the small size of the vein (3 mm). In all others, the grafts were patent on follow-up arteriography and transcranial Doppler studies. Three patients who had severe reduction of cerebral blood flow during test occlusion of the ICA exhibited temporary hemispheric neurological deficits postoperatively; the deficits were related to the duration of temporary ICA occlusion. All three recovered completely without evidence of infarction on computerized tomography (CT). One patient who clinically could not tolerate the balloon occlusion test of the ICA also had temporary neurological deficits with good recovery but showed evidence of border-zone infarction on CT scans. The present role of saphenous vein graft bypass of the cavernous ICA is discussed.

On the basis of results of electrophysiological studies in patients undergoing microvascular decompression (MVD) operations to relieve hemifacial spasm (HFS), we have postulated that the abnormal muscle response characteristically found in patients with HFS is the result of irritation of the facial nerve by the blood vessel that is compressing the facial nerve near its exit from the brainstem in these patients. This abnormal muscle response is seen when one branch of the facial nerve is electrically stimulated and recordings are made from muscles that are innervated by other branches of the facial nerve. We further hypothesized that the facial nucleus is hyperactive in patients with HFS and that the spasm and the abnormal muscle response are results of a phenomenon known as "kindling". These hypotheses are supported by recent studies showing that chronic electrical stimulation of the facial nerve trunk in rats near the brainstem results in an abnormal muscle response that is similar to that seen in patients with HFS. In this paper, we present the results of recording from the facial motonucleus in rats that had been subjected to repeated electrical stimulation of the facial nerve. The results indicate that the abnormal muscle response in these rats was caused by changes in the function of the facial motonucleus. We interpret these results as showing that the physiological abnormalities that give rise to the signs of HFS in man are located in the facial motonucleus, and that the changes in the function of the nucleus are produced by chronic antidromic neutral activity resulting from close contact between a blood vessel and the facial nerve.

The main difficulty in dealing with intradural lesions located ventrally in the region of the craniovertebral junction (CVJ) is related to their relative inaccessibility. Posterolateral approaches involve some manipulation of the brain stem and provide limited access because of the necessity of working between the cranial nerves. Even then, the view of the ventral midline and across is limited. The transoral approach, which has been widely used for the management of extradural lesions in this area, is also useful for the treatment of intradural lesions. It provides an unimpeded although somewhat restricted, view of the ventral aspect of the CVJ without the need for brain retraction. The cranial nerves and vertebral arteries are not interposed between the surgeon and the lesion. The risks of cerebrospinal fluid leakage and infection are greatly diminished by the use of fibrin adhesive and prolonged diversion of the cerebrospinal fluid. The use of this approach, together with its technical difficulties and results, in the management of seven purely intradural lesions located ventrally at the CVJ, is discussed.

Meningiomas and neurofibromas are the most common intradural extramedullary tumors of the foramen magnum and cervical spine. Many of these tumors are located ventral or ventrolateral to the spinal cord and medulla. Posterior approaches, although adequate for the management of most of these tumors, can sometimes result in incomplete removal of the tumor and exacerbation of the neurological deficits. Although the transoral and transcervical approaches provide a direct route to the tumor, the exposure of the lateral margins in the case of large tumors is inadequate. In addition, because of the removal of vertebral bodies, subsequent fusion may be necessary. In the present report, an extreme lateral approach to the foramen magnum and cervical spine for the removal of intradural tumors is described. The approach provides a lateral exposure of the tumor-cord/stem interface, thus permitting safe dissection without retraction of the cord. The entire longitudinal and lateral extent of the tumor and also its extradural extension can be can be managed by this approach. This approach can be considered in such a group of patients harboring entirely ventral or recurrent tumors for which the conventional posterior approach has failed. Six patients who underwent this procedure are described to illustrate its application.

Reconstruction of surgical defects in 30 patients undergoing surgery of the anterior cranial base was performed using pericranial, galeopericranial, and galeal scalp flaps. Twenty-seven patients had resection of neoplasms, the majority of which were malignant. Fifty-seven percent of patients received prior therapy consisting of surgery and/or radiotherapy. Adequate healing of the cranial base was noted in all cases without persistent cerebrospinal fluid leaks, meningitis, or brain herniation. Mucosalization of the intranasal surface was noted. No skin grafts were used. At a median follow-up of 13 months, 67% of patients were alive with no evidence of disease. The pericranial, galeopericranial, and galeal flaps are highly reliable, versatile, and well suited for reconstruction of the anterior cranial base.

Summary Responses from the dorsal surface of the exposed dorsal column nuclei (DCN) in baboons and a monkey (Macaca fascicularis) were recorded in response to electrical stimulation of the posterior tibial nerve at the ankle, the common peroneal nerve at the knee, the sciatic nerve, the spinal cord at Tl0, and the median nerve at the wrist. Recordings of far-field potentials from the vertex with a non-cephalic reference were made before exposing the DCN and simultaneously with recordings from the DCN. The response recorded from the DCN using a monopolar electrode to median nerve stimulation was a negative deflection (N wave) followed by a large and slow positive wave (P wave). The N wave was often preceded by a small positive deflection. The response from the median nerve to electrical stimulation of the DCN had the same latency as the initial positive peak and the initial portion of the N wave in the response from the DCN to stimulation of the median nerve, indicating that the initial positive peak was generated by presynaptic events in the DCN. The response recorded from the surface of the DCN to stimulation of the lower limbs consisted of many irregular waves followed by a large, positive deflection. Sometimes these irregular waves were superimposed on a small negative peak, and they were preceded by a positive deflection. The response from the tibial nerve to stimulation of the DCN consisted of a series of waves that had the same latency as the waves of the response from the DCN to stimulation of the tibial nerve. When interpreting the data from responses to stimulation of the lower limbs it must be kept in mind that the peaks in the far-field responses are less pronounced than they are in the responses to stimulation of the upper limbs. The response recorded from the surface of the DCN is more complex than that recorded in response to stimulation of the upper limbs.

Forty-two patients with neoplasms involving the cavernous sinus had operations between 1983 and 1987. The lesions included 25 benign tumors (e.g., meningioma, neurilemoma) and 17 malignant tumors (e.g., chondrosarcoma, adenoid cystic carcinoma). The cavernous sinus was entered by inferior, anterolateral, or medial extradural approaches or by superior or lateral intradural approaches. The intracavernous internal carotid artery was managed by dissecting tumor away from it or by occlusion and excision with or without direct vein graft reconstruction, based on the results of a preoperative balloon occlusion test. Cranial nerves III, IV, V, and VI usually were dissected from tumor, but in 3 cases of tumor invasion, the excised nerve segment was reconstructed by direct suture or with a sural nerve interposition graft. Twenty-one of the benign tumors and 8 of the malignant tumors were excised totally and the remainder subtotally. On follow-up ranging from 3 to 48 months, one subtotally excised meningioma recurred and was treated with reexcision and adjuvant radiation therapy. Two “totally” excised malignant tumors recurred outside the cavernous sinus at the margins of excision. There was no operative mortality or permanent cerebral morbidity. Postoperatively, the ocular and neurological function of most patients was similar to the preoperative status; in some, it was significantly improved. Thirteen additional patients with intracavernous neoplasms also were evaluated during the same period and followed without operation. The early follow-up information regarding these patients is provided.

We show in this paper that daily electrical stimulation of the facial nerve near its entrance to the brain stem in rats results in abnormalities in the electromyographic response of the facial muscles that resemble those seen in patients with hemifacial spasm. After about 4 weeks of daily electrical stimulation of the facial nerve for 1 min/day, stimulation of the temporal branch of the facial nerve resulted in an abnormal EMG response from the mentalis/orbicularis oris muscles, consisting of an initial deflection with a latency of about 6 ms, followed by a burst of EMG activity lasting 10 to 50 ms. We found such "lateral spread" of antidromic activity in all 10 rats that were subjected to chronic stimulation, but not in normal rats and not in rats that had electrodes implanted but which had not been stimulated. Measurements of neural conduction times suggest that the location of the cross transmission that gives rise to this lateral spread response is central to the site where the facial nerve exits the brain stem, probably in the facial motor nucleus. We take these results to support the hypothesis that chronic stimulation of the facial nerve can change the facial nucleus in such a way that it becomes hyperactive, and cross transmission between neurons that are innervating different facial muscles is facilitated.

Between 1980 and 1988, 8 patients with chordomas and 9 with low-grade chondrosarcomas involving the cranial base were treated. All the patients were investigated preoperatively and postoperatively with computed tomographic or magnetic resonance imaging scans, according to a standard protocol. The tumors and the involved bony structures were surgically removed in one or more operations using different operative approaches. Ten patients underwent postoperative radiation therapy, either at our institution or prior to their referral to us. Total removal was defined as the absence of identifiable tumor on magnetic resonance imaging or computed tomographic obtained 3 months postoperatively, and was accomplished in 9 patients. The ability to achieve total removal was greatly increased in patients with tumors that had not previously been operated on. We believe that these tumors must be treated by aggressive surgical resection when initially diagnosed, and this can be accomplished with low morbidity. The follow-up period in our patients was too short to allow us to determine whether such total removals can result in a cure or in long-term control of these formidable tumors.

By monitoring spinal cord function during surgical procedures in and around the spinal cord, vital information can be obtained regarding the integrity of this structure. However, the techniques currently used have several limitations. This paper describes a system of monitoring in the cat, whereby, using electrodes placed outside the spine for stimulation of the cord, reproducible responses can be recorded from a midline electrode tapped into the calvarium overlying the sensorimotor cortex. The levels of activation of the spinal cord achieved by direct stimulation of the cord through epidural electrodes and by the epispinal method were found to be similar. By studying the effects of various lesions on the epispinal evoked response, components in the recorded response were identified that were carried in all three funiculi of the cord; the changes produced by these lesions in the epispinal evoked response were immediate. In addition, the sensitivities of the epispinal evoked response and of the somatosensory evoked response to the lesions were compared. When the dorsal blood supply was interrupted, it became evident that, unlike the somatosensory evoked response, which monitors only the dorsal blood supply, the epispinal evoked response monitors both the dorsal and ventral blood supply. By evaluating the recorded response obtained using this method of monitoring, it was possible to identify the particular quadrant of spinal cord injury.

The case described is thought to be the first report of ulnar neuropathy caused by a cystic myxomatous degeneration of fat necrosis. The 12-day preoperative duration of symptoms is also the shortest reported for nontraumatic ulnar neuropathy; the average period between onset of symptoms and operation is 10 months. At operation, the patient's nerve was found to be stretched severely over the tumor, which was excised, thus decompressing the ulnar nerve. The procedure relieved the patient's symptoms of tingling and numbness, and he remained asymptomatic at the 12-month follow-up examination.