Dennis Y. Wen

Complications of subcutaneous low-dose heparin therapy in neurosurgical patients

BACKGROUND Venous thromboembolism is a major cause of postoperative morbidity and mortality in neurosurgery. The use of low-dose unfractionated heparin therapy perioperatively for prophylaxis against deep vein thromboses and pulmonary embolism has been well demonstrated in many other surgical specialties but is less commonly used in neurosurgery because of fears of devastating postoperative hematomas. METHODS The safety of such therapy has been analyzed in 950 patients undergoing an inpatient neurosurgical procedure. 872 patients (152 cranial procedures) completed treatment with 5000 U sodium heparin subcutaneously twice a day, commencing before surgery and continuing till patients were ambulatory. RESULTS There were three minor hemorrhagic complications-two superficial wound hematomas (one requiring treatment) and one gastrointestinal hemorrhage-identified. Three clinically significant major complications developed, two epidural hematomas after spinal surgery requiring evacuation and one intraventricular hemorrhage after brain biopsy. CONCLUSION This report, along with an analysis of previously published reports of low-dose perioperative heparin therapy in neurosurgical patients, suggests that such therapy is unlikely to be associated with increased morbidity. Given the known efficacy of low-dose heparin in reducing venous thromboembolism in other surgical patients, such therapy may reduce mortality and morbidity from thromboembolic complications in neurosurgical patients with minimal risk.

Targeted brain biopsy: a comparison of freehand computed tomography-guided and stereotactic techniques.

With computed tomography (CT) and magnetic resonance imaging stereotactic systems, biopsies of intracranial lesions can be made with safety and ease. Before the development of this technique, neurosurgeons often performed freehand brain biopsies under CT guidance. While stereotactic biopsy is the procedure of choice for small, deep lesions, few studies have compared the morbidity, mortality, and efficacy in obtaining a diagnosis associated with these two techniques for superficial lesions. A total of 167 consecutive CT-guided or stereotactic brain biopsies were performed in 154 patients. Fourteen of the stereotactic and 12 of the CT-guided biopsies were of deep lesions and were excluded from analysis. The results of 75 freehand CT-guided biopsies of superficial lesions in 69 patients were compared with those of 66 stereotactic biopsies (34 CT-guided and 32 MRI-guided) performed with the Brown-Roberts-Wells stereotactic system in 60 patients. Twenty-five of the lesions in the stereotactic biopsy group measured < or = 2 cm, as compared with 13 of those in the freehand CT-guided biopsy group. There were no biopsy-related deaths among the patients who underwent freehand CT-guided biopsy and one death among those who underwent stereotactic biopsy (1.5%). Freehand CT-guided biopsy was associated with 5% morbidity, compared with 6% morbidity for stereotactic biopsy. Seven CT-guided needle biopsies (9%) and 12 stereotactic biopsies (18%) were nondiagnostic. Statistical analysis showed no significant difference between morbidity and mortality in the two groups, but the rate of diagnostic failure was significant (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Infections in neurologic surgery. The intraventricular use of antibiotics.

Intraventricular antibiotics represent an important and effective mode of therapy for several central nervous system infections, especially ventriculitis and shunt infections. The efficacy, pharmacokinetics, and toxicity of various antibiotics commonly used for intraventricular therapy are discussed. Vancomycin is an extremely effective and safe agent. Gentamicin has been associated with reports of toxicity but remains useful because of the wealth of clinical experience reported for this agent.

Targeted Brain Biopsy

With computed tomography (CT) and magnetic resonance imaging stereotactic systems, biopsies of intracranial lesions can be made with safety and ease. Before the development of this technique, neurosurgeons often performed freehand brain biopsies under CT guidance. While stereotactic biopsy is the procedure of choice for small, deep lesions, few studies have compared the morbidity, mortality, and efficacy in obtaining a diagnosis associated with these two techniques for superficial lesions. A total of 167 consecutive CT-guided or stereotactic brain biopsies were performed in 154 patients. Fourteen of the stereotactic and 12 of the CT-guided biopsies were of deep lesions and were excluded from analysis. The results of 75 freehand CT-guided biopsies of superficial lesions in 69 patients were compared with those of 66 stereotactic biopsies (34 CT-guided and 32 MRI-guided) performed with the Brown-Roberts-Wells stereotactic system in 60 patients. Twenty-five of the lesions in the stereotactic biopsy group measured < or = 2 cm, as compared with 13 of those in the freehand CT-guided biopsy group. There were no biopsy-related deaths among the patients who underwent freehand CT-guided biopsy and one death among those who underwent stereotactic biopsy (1.5%). Freehand CT-guided biopsy was associated with 5% morbidity, compared with 6% morbidity for stereotactic biopsy. Seven CT-guided needle biopsies (9%) and 12 stereotactic biopsies (18%) were nondiagnostic. Statistical analysis showed no significant difference between morbidity and mortality in the two groups, but the rate of diagnostic failure was significant (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute cervical myelopathy from hereditary multiple exostoses: case report

A case of hereditary multiple exostoses with acute cervical myelopathy, tetraplegia, and apnea is reported. Neurological complications as a result of osteochondromas in hereditary multiple exostoses are rare. The majority of osteochondromas in the cervical spine arise from the neural arch. Magnetic resonance imaging and computed tomography are invaluable in localizing the origin of the lesion and its relationship to the spinal cord. Decompressive laminectomy usually results in excellent functional recovery. Where significant dorsal spinal cord compression exists without neurological deficit, prophylactic decompression can be recommended.

Microsurgical management of craniopharyngiomas

A retrospective analysis of 34 patients who underwent microsurgical therapy for craniopharyngioma from 1975 to 1989, a period when CT imaging was routinely used, is presented. Mean follow-up was 6.4 years with no patients lost to follow-up. Those who underwent subtotal resection with adjuvant radiation had a significantly better recurrence-free interval compared with those who either underwent total or subtotal surgical resection only (p < 0.05 and p < 0.025). Among patients treated with surgery alone, the total resection group had a recurrence rate of 20% and those with a subtotal resection 60%. Those with subtotal resection and radiation had a 12% rate of recurrence. Endocrine and visual deficits were common after surgery. Based on this review, our results suggest that with a policy of attempted total resection where possible, subtotal removal along with adjuvant radiation, in cases where total resection was deemed unsafe, may be more effective than aggressive total resection alone as the initial management of craniopharyngioma.

In vitro and in vivo variation in transferrin receptor expression on a human medulloblastoma cell line

The poor prognosis associated with pediatric central nervous system tumors such as medulloblastoma has led to the development and investigation of a variety of new treatment techniques. Therapeutic agents include targeted-toxin conjugates or immunotoxins that show significant in vitro activity against many brain tumors. Transferrin receptors (TRs) are specific, cell-surface antigens that are expressed preferentially on brain tumors rather than on normal human brain tissue. This antigen has been successfully targeted in human and nonhuman brain tumors in vitro and in vivo. In this study, when TRs were used as a target in the DAOY human medulloblastoma-derived cell line in vitro, a significant level of expression was confirmed by testing the sensitivity to different immunotoxins. To ensure the relevance of the in vitro data to the in vivo situation, we also analyzed TR expression in DAOY tumors growing in athymic mice and rats. Immunocytochemistry, immunohistochemistry, immunobead binding, immunofluorescence, 125iodine-transferrin binding, and Northern blot analysis were used to compare TR expression in DAOY cells in vitro and in vivo. All in vitro assays demonstrated significant TR expression, whereas in vivo, the TR expression was negligible in the DAOY tissue. The results caution against extrapolating in vitro antigen and receptor expression data directly to the in vivo situation. Using a transferrin-toxin conjugate in a nude rat model of leptomeningeal carcinomatosis, we achieved therapeutic efficacy, despite demonstrating reduced TR expression on tumor tissue. With respect to clinical efficacy, the reduced expression of TR on DAOY medulloblastoma in vivo may be less significant than expected because of the extreme potency of immunotoxins observed in central nervous system tumors.

Surgical management of cervical radiculopathy caused by redundant vertebral artery loop

In this article, the authors describe the case of a 27-year-old female presenting with a 2-year history of neck pain and radiculopathy attributable to compression of the right C-7 nerve root by tortuosity of the vertebral artery at the level of the C6-7 cervical foramina. An anterolateral approach to the transverse foramen was used to perform a vascular decompression to decompress the nerve root. The procedure was uneventful, and the patient woke up with almost all of her symptoms resolved. The authors also include a literature review of techniques performed in this setting, showing that multiple surgical approaches can be used and should be tailored to the patient symptoms and lesion characteristics.

Gene therapy for neurodegenerative disorders and malignant brain tumors

Gene therapy approaches have great promise in the treatment of neurodegenerative disorders and malignant brain tumors. Neuwelt et al. review available viral-mediated gene therapy methods and their blood-brain-barrier (BBB) disruption delivery technique, briefly mentioning nonviral mediated gene therapy methods. This commentary discussed the BBB disruption delivery technique, viral and nonviral mediated gene therapy approaches to Parkinsons disease, and the potential use of antisense oligo to suppress malignant brain tumors.