Transthoracic anterolateral decompression for thoracic spinal lesions.

Since 1978, the authors have treated 11 patients with lesions of the ventral thoracic spine via a transpleural anterolateral approach. Each of the patients presented with pain and paraparesis, 8 had sensory dysfunction, and 6 had demonstrated sphincteric disturbances. All 11 had radiographic confirmation of anterior cord compromise, and each underwent an anterior decompression, with 8 requiring graft stabilization. There were no surgical mortalities, and the postoperative complications were limited. In follow-up, 10 of the 11 patients had complete resolution of their preoperative pain and were able to ambulate independently. Remission of sensory disturbances was noted in 6 patients, and 5 regained sphincteric control. The authors have found that this approach is both safe and effective, with several advantages over conventional laminectomy and posterolateral techniques.

Primary intracranial rhabdomyosarcoma.

Primary intracranial rhabdomyosarcoma is rare. Twenty-one cases with dismal outcomes have been reported. We add five children with this disease treated between 1977 and 1982. Their therapy consisted of surgical resection, craniospinal irradiation, and intravenous-intrathecal chemotherapy. Two children have recovered, 21 and 67 months after diagnosis; the last is the longest survival reported in the literature. Two succumbed to tumor recurrence, and one died due to pulmonary embolism. The posterior fossa was invariably a site of tumor at presentation. Diagnosis with light microscopy can be elusive; electron microscopic and immunohistochemical evaluation are necessary to confirm the pathological condition. This is essential so that early, aggressive therapy can be instituted. These diagnostic and therapeutic techniques have led to a reevaluation of this malignancy and its prognosis.

Effect of hemorrhagic shock upon spinal cord blood flow and evoked potentials.

Although somatosensory evoked potentials are being used in the evaluation of spinal cord injury and the monitoring of cord function during surgical procedures, their limitations in the face of fluctuations in blood pressure await further clarification. To study the effect of hypotension upon spinal cord blood flow (SCBF) and spinal evoked potentials (SEPs), we subjected five anesthetized lambs to graded hypotension to a mean arterial pressure (MAP) of 80, 60, 40, and less than or equal to 30 mm Hg. Five animals served as controls. Maximal hypotension was associated with a significant decrease in renal and sciatic nerve blood flow of 83% and 77%, respectively. SCBF, on the other hand, showed no decrease with hypotension down to a MAP of 40 mm Hg. As hypotension progressed, a gradual but significant slowing in nerve conduction velocity was noted without alteration in the cord conduction velocity from L7 to L1. Control animals demonstrated a decline in sciatic nerve blood flow of 48%, without any change in latency or amplitude of nerve action potentials. These findings suggest that, in hypotension, the peripheral nerve (lacking autoregulation) becomes ischemic, resulting in slowing of nerve conduction velocity with an increase in latency and decrease in amplitude of SEPs. Cord conduction velocity, on the other hand, remains unchanged. Caution is advised in relying upon SEPs generated by peripheral nerve stimulation to monitor cord function in situations where profound hypotension is anticipated. Variations in SEPs may reflect alterations in the peripheral nerve and not the spinal cord.

Direct spinal cord stimulation and recording in hemorrhagic stock.

Somatosensory evoked potentials (SSEPs) have been used extensively to evaluate the central nervous system. A limitation of using SSEPs is that the peripheral nervous system is intrinsically linked to the production of these potentials. Peripheral nerve ischemia and neuropathies have been shown to result in changes in SSEPs that may be misinterpreted as showing a pathological condition in the central nervous system. Our experimental paradigm was designed to study the practicality and possible benefits of obtaining spinal evoked potentials (SEPs) by direct cord stimulation and recording. Twelve lambs underwent laminectomies at C-7 and L-1. Epidural electrodes were placed at each level. Each lamb was then bled to produce mean arterial pressures of 80, 60, 40, and less than or equal to 30 mm Hg. At each of these designated pressures, SEPs were obtained by direct cord stimulation and recording. At the same time, spinal cord blood flow was measured using the radioactive microsphere technique. The spinal cord blood flow remained constant down to a mean arterial pressure of 40 mm Hg, whereas blood flow to the peripheral nerve and renal cortex decreased with the mean arterial pressure. SEPs produced by this method did not vary in terms of latency or amplitude over mean arterial pressures ranging from 100 to 30 mm Hg. We conclude that SEPs produced by direct cord recording and stimulation constitute a method of assessing cord viability free of the variables attributable to the peripheral nervous system.

Effect of laminectomy and anesthesia upon spinal cord blood flow.

Spinal cord blood flow (SCBF) in 10 sheep subjected to laminectomy at L6-7, T6-7, and C7-T1 was compared to that of 10 control sheep subjected to anesthesia alone. Blood flow was measured using the radioactive microsphere technique, with the PaCO2 maintained at 40 +/- 2 mm Hg. Both laminectomy and control animals showed a decrease in SCBF at a rate of 7% to 16%/hr for the 3 hours following the first blood flow determination. When prelaminectomy and postlaminectomy SCBF values were compared to their counterparts in the control animals, there were no significant differences. Laminectomy does not appear to alter SCBF from control values. Spinal evoked potentials (SEP's) were elicited in the laminectomy group by direct cord stimulation at C-7 and L-7. No changes were noted in amplitude or latency of SEP's over time in either caudal or rostral conduction.

Cervical spine surgery and handwriting: a case report.

The 53-year-old right-handed woman underwent decompressive laminectomies and foraminotomies at the C3-C7 levels. The course of illness and postoperative recovery were documented by handwriting and MRI views, but not statistical analysis.

Behavioural manifestations of third ventricular colloid cysts.

Three patients with third ventricular colloid cysts manifested disturbances of memory, emotion and personality in the absence of hydrocephalus. All three patients demonstrated significant improvement following removal of the tumours. The symptoms and signs associated with these neoplasms may be attributed to compression or vascular compromise of the diencephalon with disorder of major limbic system structures. Tumour removal should be undertaken in patients with symptoms even in the absence of hydrocephalus, and ventricular shunting may be inadequate as a sole therapeutic measure.