Robert G. Ojemann

Spinal epidural abscess.

In an editorial describing his clinical experience of spinal epidural abscess, Heusner (1948) reminds us that “… the decisive factor in the outcome of most cases is the celerity with which the first physician suspects the probable nature of the ailment and summons expert aid”. On pathological grounds he recognized three presentations: (1) an acute metastatic presentation which evolves over hours to days and where the epidural abscess cavity contains frankly purulent material; (2) a subacute presentation evolving over days to weeks where the epidural abscess cavity comprises granulation tissue without significant quantities of necrotic material; (3) a chronic presentation, most often associated with osteomyelitis. The last accounted for only 10% of his series and involved a broader differential diagnosis. In more recent series (Hlavin et al. 1990; Nussbaum et al. 1992; Darouiche et al. 1992; Corboy and Price 1993) this classification has been less distinct with the acute variety predominating.Thirty-nine patients with spinal epidural abscess were evaluated at the Massachusetts General Hospital between 1947 and 1974. Twenty had acute symptoms, and purulent epidural collections were present; 19 had prolonged courses, and epidural granulation tissue was observed at operation. Staphylococcus aureus was the most common etiologic agent (57 per cent), followed by streptococci (18 per cent) and gram-negative bacilli (13 per cent). The source of infection was osteomyelitis in 38 per cent of cases and bacteremia in 26 per cent. In 16 per cent epidural abscess was due to postoperative infection. The progression from spinal ache to root pain to weakness followed by paralysis continues to be characteristic of spinal epidural abscess. Although the disease is uncommon, the complications are so serious that prompt diagnosis and treatment are of paramount importance. The combination of back pain with fewer and local tenderness is an indication for cerebrospinal-fluid examination and, depending on the results, immediate performance of myelography.

Cerebral vasospasm with ruptured saccular aneurysm--the clinical manifestations.

Fifty cases of verified intracranial ruptured saccular aneurysm were analyzed to investigate the relationship of the development of a delayed cerebral ischemic deficit to the presence of cerebral vasospasm visualized on angiography. Twenty-five patients developed a delayed ischemic deficit (DID), and all showed Grade 3+ or 4+ vasospasm. Nineteen patients had Grade 0, 1+, or 2+ vasospasm, and none developed a DID. It was concluded that in this study vasospasm accounted for all DIDs and that in the absence of vasospasm DID did not occur. The DID occurred most often on Day 8 (7 of 25 cases).

The relation of cembral vasospasrn to the extent and location of subarachnoid blood visualized by CT scan: A prospective study

In 41 cases of verified ruptured saccular aneurysm, we prospectively predicted the presence or absence of delayed symptomatic cerebral vasospasm. CT criteria quantifying the extent and location of subarachnoid blood (developed in our previous retrospective study) were used in this prospective series of patients. Twenty-two patients had recognizable subarachnoid clots larger than 3×5 mm or layers of blood more than 1 mm thick (measured on reproduced images). In 20 of the 22 patients with severe significant clot or thick layer, severe vasospasm was correctly predicted and localized (2 false positives). In 19 patients with no blood, or diffuse blood, or blood outside the subarachnoid space, the absence of severe vasospasm was correctly predicted in 14 (5 false negatives). All of the false-positive and false-negative cases could be explained by inadequate CT technique. The data indicate that the extent and location of blood in the subarachnoid space determine the severity and location of vasospasm and that patients in jeopardy of developing symptomatic cerebral vasospasm can now be identified. Early preventive measures may now be assessed more accurately.

Large and giant paraclinoid aneurysms: Surgical techniques, complications, and results

Twenty-five patients with giant (greater than 25 mm in diameter) and 9 patients with large (15 to 25 mm in diameter) aneurysms of the internal carotid artery in the ophthalmic or paraophthalmic region are reviewed. In 23 of these patients the aneurysm was clipped directly. There was 1 death in this group, and none of the survivors had disabling neurological complications outside the visual system. The other 11 patients were treated by a trapping procedure or by either common carotid ligation or internal carotid ligation in the neck. Of the 5 patients treated by internal carotid ligation preceded by an extracranial to intracranial bypass graft, 3 developed embolic complications, which in 1 patient resulted in death. One of the 4 patients treated by ligation of the common carotid artery died 1 year later from a recurrent subarachnoid hemorrhage. Of the total group, 18 patients had visual loss preoperatively as a result of aneurysmal compression; in 10 the vision was improved by operation, in 3 it was made worse, and in 2 it was unchanged. In another patient the vision continued to deteriorate slowly after common carotid occlusion, and the other 2 patients died postoperatively before vision could be assessed. The complications in the patients are described and analyzed in detail. Maneuvers found to be of value in the direct approach to these lesions are described. Of these, exposure of the internal carotid artery in the neck for temporary occlusion during clipping and thorough drilling of the anterior clinoid process and unroofing of the optic canal were particularly helpful. The literature on indirect methods of treatment by carotid occlusion with and without bypass graft is reviewed with special reference to the complications and effectiveness of each alternative. Based on this review of the literature and our experience, a treatment scheme is suggested for these aneurysms depending on their mode of presentation.

Management of Atypical and Malignant Meningiomas: Role of High-dose, 3D-conformal Radiation Therapy

AbstractObjective Atypical and malignant meningiomas are at high risk for local failure. The role of radiation therapy (RT) and dose levels required to improve tumor control are poorly defined. This study reviews our experience with RT. Material and methods Thirty-one patients underwent fractionated RT for atypical (AM, 15 patients) or malignant meningioma (MM, 16 patients) of the cranium. Sixteen patients presented with primary and 15 with recurrent disease. Eight patients received RT following total resection, 21 patients after subtotal resection and 2 patient following biopsy only. RT was given using megavoltage photons in 15 patients and combined photons and 160 MeV protons in 16 patients. Total target doses ranged from 50 to 68 (AM, mean 62) and from 40 to 72 (MM, mean 58) Gy or CGE (= cobalt-gray-equivalent). Results With mean observation time of 59 months (range: 7–155 months) actuarial local control rates at 5- and 8-years were similar for both histologies (38% and 19% for AM and 52 and 17% for MM). However, significantly improved local control was observed for proton versus photon RT (80% versus 17% at 5 years, p = 0.003) and target doses ≥60 Gy for both, atypical (p = 0.025) and malignant meningioma (p = 0.0006).At time of analysis, 14/15 patients (93%) with AM and 6/16 (38%) with MM were alive. Three patients (19%) with MM developed distant metastasis. Actuarial 5- and 8-year survival rates for MM were significantly improved by use of proton over photon RT and radiation doses ≥60 CGE. Three patients developed symptomatic radiation damage after 59.3, 68.4 and 72 Gy/CGE. Conclusion Conformal, high dose RT resulted in significant improvement of local control for atypical and malignant meningiomas. Increased local control resulted also in improved rates of survival for patients with malignant meningioma.

Long-term recurrence rates of atypical meningiomas after gross total resection with or without postoperative adjuvant radiation.

OBJECTIVEAtypical meningioma (AM) patients often undergo gross total resection (GTR) at the time of presentation, but subsequent prognosis and optimal management remain unclear. We sought to define the long-term recurrence rate of AMs after GTR, along with factors predicting recurrence, including postoperative radiation. METHODSWe performed a retrospective review of 108 AMs after GTR at our institution from 1993 to 2004. Recurrence risk factors were analyzed using multivariate Cox regression. RESULTSThere were 600 patient-years of imaging follow-up on 48 men and 60 women. Of 108 tumors, 30 (28%) recurred 3 to 144 months after GTR (mean, 36 months). Actuarial tumor recurrence rates were 7% (1 year), 41% (5 years), and 48% (10 years). Of 108 patients, 8 received postoperative radiation without recurrence (P = 0.1). Multivariate analysis including age, sex, postoperative radiation, tumor location, MIB-1 labeling index, and 6 atypical-defining histological features identified recurrence-predicting factors: older age (hazard ratio, 1.6/decade; P = 0.01), sheeting (hazard ratio, 2.2; P = 0.025), and prominent nucleoli (hazard ratio, 2.1; P = 0.034). Recursive partitioning identified a subset, men with mitoses and prominent nucleoli, with 70% recurrence (n = 14). All patients with recurrences received radiation, and 22 of 30 patients underwent craniotomies (average, 2.7 craniotomies per patient with recurrence; range, 1–7 craniotomies). Only 1 of 22 re-resected meningiomas underwent malignant transformation. Of 30 patients with recurrence, 10 experienced tumor-induced mortality an average of 7 years after recurrence (range, 1–14 years). CONCLUSIONAfter GTR without postoperative radiation, AMs have a high recurrence rate. Most recurrences occurred within 5 years after resection. Recurrences caused numerous reoperations per patient and shortened survival. Our finding suggesting lower recurrence rates in patients undergoing immediate postoperative radiation should be investigated in larger, prospective series.

Definitive radiation therapy for chordoma and chondrosarcoma of base of skull and cervical spine.

: Proton-beam radiation therapy has been developed for the treatment of chordomas or sarcomas of bone or soft tissue that abut the central nervous system. The authors report the results of treatment of 10 patients, six with chordoma, three with chondrosarcoma, and one with a neurofibrosarcoma. Local control has been achieved for all patients (with, however, one marginal failure) with a follow-up period ranging from 2 months to 6 years. High doses of radiation, up to 76 Cobalt Gray Equivalents (CGE), have been delivered without significant morbidity. In particular, no neurological sequelae have been observed.

Intramedullary cavernous angiomas of the spinal cord: clinical presentation, pathological features, and surgical management.

Cavernous angiomas of the spinal cord are rare lesions that can cause severe neurological symptoms. We add a series of 6 patients with intramedullary cavernous angiomas of the spinal cord to 30 patients with 31 histologically verified lesions already described in the literature. Four types of clinical presentation were seen in the 36 patients: 1) discrete episodes of neurological deterioration with varying degrees of recovery between episodes (13 patients); 2) slow progression of neurological decline (12 patients); 3) acute onset of symptoms with rapid decline (8 patients); and 4) acute onset of mild symptoms with subsequent gradual decline lasting weeks to months (3 patients). Of the 36 patients, 25 (69%) were women and 11 (31%) were men. The peak age of presentation was in the fourth decade. The thoracic spinal cord was affected in more than half the patients, with the cervical cord being the next most common location. Histological examination demonstrated the closely apposed vascular channels characteristic of cavernous angiomas. While most vascular channels were thickened and hyalinized, three angiomas had foci of small vessels resembling a capillary angioma. The available data suggest that surgical management of intramedullary angiomas should attempt complete extirpation. The lesions are often well circumscribed with a glial plane between the lesion and normal cord. However, spinal cord angiomas, unlike cranial lesions, have little room for enlargement before devastating symptoms occur. We achieved complete excision in all of our patients, who are all ambulatory and have improved symptoms. Little, if any, increase in neurological deficit was caused by myelotomy and lesion excision. These spinal lesions should be considered for surgery early, before repeated hemorrhage or enlargement can occur.

Temporal clustering of hemorrhages from untreated cavernous malformations of the central nervous system

OBJECTIVEHemorrhages from cerebral cavernous malformations (CMs) sometimes seem to occur in closely spaced “clusters” interspersed with long hemorrhage-free intervals. Clustering of hemorrhages could affect retrospective assessments of radiosurgery efficacy in prevention of CM rehemorrhage. However, this empirical observation had not been tested quantitatively. To test whether CM hemorrhages tend to cluster, we reviewed pretreatment rebleeding rates after a first symptomatic hemorrhage in CM patients who later underwent surgery or radiosurgery. METHODSWe performed a retrospective review of 141 patients with CMs who presented with clinically overt hemorrhage, and who subsequently underwent surgery or proton beam radiosurgery during an 18-year period. Statistical models were used to analyze all events per person and identify potential variation in rebleeding risk with time after a previous hemorrhage. RESULTSSixty-three of 141 patients experienced a second hemorrhage before treatment; 16 had additional hemorrhages. Five hundred thirty-eight patient years elapsed between first hemorrhages and treatment. The cumulative incidence of a second hemorrhage after the first CM hemorrhage was 14% after 1 year and 56% after 5 years. During the first 2.5 years after a hemorrhage, the monthly rehemorrhage hazard was 2%. The risk then decreased spontaneously to less than 1% per month, which represents a 2.4-fold decline (P < 0.001). Rehemorrhage rates were higher in younger patients (P < 0.01), but not in females or in patients with deep lesions. Shorter intervals between successive hemorrhages did not predict higher subsequent rehemorrhage risk. CONCLUSIONThe rehemorrhage rate from untreated CMs is high initially, and it decreases 2 to 3 years after a previous hemorrhage. This hazard pattern generates the observed temporal clustering of hemorrhages from untreated CMs.

Surgical treatment of acoustic neuroma (vestibular schwannoma) in the United States: report from the Acoustic Neuroma Registry.

In 1989, the Acoustic Neuroma Association established a multisurgeon, multi‐institutional registry to collect data related to the treatment of patients with acoustic neuroma. This report analyzes information from the 1579 surgically treated patients who were entered in the registry between January 1, 1989, and February 28, 1994.