Neurological deterioration is commonly seen after surgical excision of clival meningiomas; however, an understanding of the risk factors associated with postoperative deterioration can lead to improvements in outcome. In 75 patients with clival meningiomas operated on over a 7-year period, the following data were studied; preoperative variables such as presenting Karnofsky scale score, age, sex, and prior operations or radiation therapy. Radiological findings on magnetic resonance imaging or arteriography, such as the development of the arachnoidal cleavage plane between tumor and the brain stem, brainstem edema, tumor size, extent of compression on the brain stem, vascular encasement, and blood supply from the basilar artery were among other data studied. In addition, intraoperative findings such as development of the arachnoid plane, vascular encasement, and the difficulty of dissection were noted. Finally, each patient's neurological and functional statuses were recorded at 1 week postoperatively and at follow-up examinations. Early postoperative functional deterioration occurred in 45 patients (60%) and ranged from mild (30 patients) to severe (three patients). Significant improvement had occurred by the time of follow-up examination in all but four patients; however, permanent postoperative dysfunction was present in 12 patients. Statistical analysis revealed significant correlations between early functional deterioration and preoperative Karnofsky scale scores, male gender, radiological findings of the absence of an arachnoid plane, edema of the brain stem, and arteriographic supply from the basilar artery. Operative features included difficulty with dissection, an absent arachnoidal cleavage plane, and incomplete tumor resection. Permanent functional deterioration was statistically associated with the following: blood supply from the basilar artery, difficulty of dissection, incomplete tumor resection, and early postoperative dysfunction. Logistical regression analysis revealed that the most important risk factor for early postoperative deterioration was tumor size. Patients with large or giant tumors had a 6.7 to 13 times greater risk of functional deterioration, respectively, than patients with small- or medium-sized tumors. Excluding tumor size, the most important factor for permanent deterioration was blood supply from the basilar artery. Patients in this category had a 4.4 times greater risk of permanent functional deterioration. Three stages of tumor relationship to the brainstem arachnoid and pial membranes are proposed. Based on the results of this clinical study of clival meningiomas, suggestions are made for changes in the management strategy of these difficult lesions.

INCE Mixter and Barr 21 first described herniated lumbar intervertebral disc-induced nerve root compression, numerous operative approaches have been used for treatment. Neural compromise caused by a herniated disc outside the confines of the spinal canal is more readily recognized by using computerized tomography and magnetic resonance imaging. Such herniations have been characterized as foraminal, 8 extraforaminal, 15 extreme-lateral, 1,23 far-lateral, 19 and extracanalicular 25 disc prolapse. We prefer the term "extraforaminal" because the boundaries of the neural foramen can be readily identified on computerized tomography and magnetic resonance images, and because extraforaminal lesions are distinct from intraspinal-foraminal, foraminal, and foraminal-extraforaminal lesions.The clinical and radiological characteristics of extraforaminal lesions have been reported. 1,8,10,14,23 Currently two surgical approaches commonly used for the treatment of this type of disc herniation are 1) a conventional approach via a midline laminotomy/fenestration, or one of its modifications, and 2) a paramedian approach. Removal of a truly extraforaminal herniated disc via the midline approach necessitates sacrificing a significant portion, if not all, of the facet joint. The paramedian approach, however, which is performed at the level of the facet joint, provides a more direct route to this lesion. Although several Materials and Methods Anatomical StudiesTwenty-four lumbar extraforaminal disc spaces were studied in three human cadavers. In one cadaver predissection, the arteries and Object. Familiarity with the microsurgical anatomy of the far-lateral compartment is essential for operating in patients with far-lateral discs. In this report the authors address the microsurgical anatomy studied in 24 extraforaminal lumbar disc spaces in three cadavers.Methods. Cadaveric dissections confirmed the authors' operative experience in which they found an arterial arcade to be associated with the nerve trunk. The main trunk of the lumbar artery was located lateral to the exiting nerve root in the region of intervertebral foramen. The trunk of the lumbar spinal nerve descending from the level above was 7 mm (Ϯ 3 mm [standard deviation]) lateral to the lumbar artery.Conclusions. Clarification of the microsurgical anatomy of the far-lateral compartment confirmed the authors' clinical impression that the optimum approach to far-lateral discs is via the inferomedial quadrant of the extraforaminal compartment. In this quadrant, exposure of the main nerve root can be facilitated by dividing the posterior primary ramus and a newly described arterial arcade that envelops the nerve trunk. Once this arcade is divided, the nerve can be retracted with relative ease and safety, and the disc can be removed more easily. KEY WORDS • spine • lumbar intervertebral disc • microsurgery • anatomical study • surgical approachS

After excluding more common causes of spontaneous subarachnoid hematoma in this patient, we suggest that chronic spinal cord compression (spondylotic myelopathy) and arterial hypertension in this patient may have caused the pathogenesis of this rare clinical entity. Experimental data supporting this hypothesis are discussed.

There is limited evidence to suggest that anterior approaches for the resection of ventral intramedullary lesions of the cervical spinal cord may result in superior neurological outcomes compared with those following more traditional posterior approaches. To the authors’ knowledge, no report of an anterior approach to resect a ventral intramedullary capillary hemangioma exists in the literature. In the following paper, the case of a 75-year-old male who presented with progressive neck and left shoulder pain, weakness of the left hand, myelopathy, and gait imbalance is reported. Postcontrast T1-weighted MRI demonstrated a homogeneously enhancing intramedullary lesion with associated severe impingement of the cervical spinal cord at C-4. Following a C-4 corpectomy, intradural exposure revealed a vascular lesion that circumferentially enveloped the anterior spinal artery. Gross-total resection of the lesion was performed, followed by reconstruction of the corpectomy defect, without neurological deterioration. Pathology was consistent with capillary hemangioma. In this instance, the anterior approach helped to avoid unnecessary neural manipulation and allowed for early identification of normal proximal and distal segments of the anterior spinal artery, which facilitated safe dissection and gross-total removal.

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