Inhibition of peridural fibrosis after laminectomy using low-dose external beam radiation in a dog model.

OBJECTIVE: Clinical studies have demonstrated a significant association between the presence of extensive postlumbar discectomy peridural scar formation and the recurrence of low back and radicular pain. Low-dose perioperative radiation therapy has previously been demonstrated to inhibit peridural fibrosis after laminectomy in a rat model. The current study was designed to measure the effect of low-dose radiation on postlaminectomy peridural fibrosis development in a larger animal model. METHODS: Three dogs underwent a total of 12 lumbar hemilaminectomies. For each animal, two levels received 1) external beam radiation 24 hours before surgery, 2) surgery alone, or 3) radiation alone. Radiation was administered in a single fraction of 700 cGy using computed tomographic guidance for dosimetry planning. The isodose distribution was such that the dose conformed to the posterior epidural space with minimal exit dose to normal tissue. Port films were used to confirm the correct levels. Gadolinium-enhanced magnetic resonance imaging (MRI) of the lumbar spines was obtained before the animals were killed 12 weeks after surgery. The spines were harvested, and axial sections through the laminectomy defect were stained with hematoxylin and eosin and Masson's trichrome. All specimens were evaluated for extent of fibrosis along the dura, density of fibrosis, nerve root entrapment, and sublaminar fibrosis. RESULTS: There were no complications from the surgery, and no new neurological deficits were noted. There was a statistically significant difference between the irradiated and nonirradiated groups regarding the extent of fibrosis (P = 0.001) and the density of fibroblasts (P = 0.001). There was also a marked difference in nerve root entrapment (P = 0.182) and the presence of sublaminar fibrosis (P = 0.061) between the treatment and control groups. MRI revealed less gadolinium enhancement at the irradiated levels compared with the nonirradiated levels, confirming the usefulness of MRI in predicting the degree of epidural fibrosis. CONCLUSION: Low-dose external beam radiation therapy administered 24 hours before laminectomy in a dog model significantly decreased the extent and density of peridural fibrosis as well as nerve root entrapment and sublaminar fibrosis. This treatment strategy may be efficacious in patients with recurrent radicular pain after lumbar discectomy that is thought to be secondary to peridural fibrosis on the basis of gadolinium-enhanced MRI studies, and who might benefit from reoperation for nerve root decompression.

Inhibition of peridural fibrosis after laminectomy using low-dose external beam radiation in a rat model.

OBJECTIVE: Clinical studies have revealed a significant association between the presence of extensive postlumbar discectomy peridural scar formation and the reoccurrence of low back and radicular pain. Low-dose perioperative radiation therapy has been shown to inhibit scar formation. Its effect on peridural fibrosis, however, has not been studied. METHODS: Thirty male Sprague-Dawley rats underwent L5 laminectomies. Ten rats each received a single fraction of 700-cGy external beam radiation to the lumbar spine 24 hours before surgery; 10 rats each received 700 cGy 24 hours after surgery. The remaining 10 rats served as a control group. All of the rats were killed 30 days after surgery. The spines were harvested, and axial histological sections through the laminectomy defect were evaluated. Each specimen was scored for extent, density, and arachnoidal involvement by fibrosis. RESULTS: There was a statistically significant difference between the treatment and control groups regarding the extent of fibrosis along the dura (P < 0.001), the density of fibroblasts (P < 0.005), and the arachnoid involvement (P < 0.01). There was no difference in fibrosis reduction between the groups receiving pre- and postlaminectomy radiation. CONCLUSION: Low-dose external beam radiation therapy administered before or after laminectomy in a rat model significantly decreases the extent, density, and arachnoidal involvement of peridural fibrosis. This technique may improve the outcome of patients who undergo reoperations for recurrent radicular and/or low back pain after successful lumbar discectomy in whom there is a significant amount of peridural fibrosis.

Fatal clival subdural hematoma in a hemophiliac.

We report the case of a hemophiliac in whom developed an unusual site of intracranial bleeding, a subdural hematoma that extended in the posterior fossa anteriorly from the clivus into the upper spinal subdural space. The hematoma was delayed in onset and was fatal. We review the current management recommendations for hemophiliac patients with head injury and the clinical presentation of intracranial bleeding in hemophiliacs. The necessity for Factor VIII replacement and serial computed tomography scans is emphasized.

Thoracic discectomy using video assisted thoracoscopy.

STUDY DESIGN: The applicability of using video assisted thoracoscopic surgery (VATS) to resect thoracic discs was investigated. A laboratory study was conducted using two human cadavers and three live pigs as surgical specimens. A total of nine thoracic levels were decompressed. OBJECTIVE: To study the feasibility of performing thoracic resections using VATS. SUMMARY OF BACKGROUND DATA: VATS has been used by thoracic surgeons since 1991 to resect pulmonary lesions. As far as we know, VAT has not yet been used to resect thoracic discs. METHODS: Surgical resections of nine disc levels were carried out in two human cadavers and three anesthetized pigs. VATS was used to provide the surgeon with visualization of the surgical site. Large thoracotomy incisions were not necessary. RESULTS: Five of seven cadaver disc spaces and two of three porcine disc spaces were adequately evacuated of disc material. One episode of dural violation occurred. One animal died during the procedure from an anesthetic complication. CONCLUSION: VATS provides a useful means of performing thoracic discectomies using a small thoracotomy incision. The decrease in invasiveness provided by this new technology may reduce operative morbidity, hospitalization time, and costs. More work is needed, especially in the design of instrumentation, before this becomes a viable alternative to current surgical procedures.

Carpal tunnel release complicated by acute gout.

We report a patient who suffered an acute attack of gout in the wrist after surgical release for carpal tunnel syndrome. The postoperative management of this patient and a brief review of this complication of carpal tunnel release are discussed.

Dorsal root entry zone lesions for conus medullaris root avulsions.

We have found dorsal root entry zone (DREZ) lesions to be an effective treatment of chronic deafferentation pain in patients who have had avulsions of the dorsal rootlets from the spinal cord. Eight patients were operated in whom chronic pain of the lower extremity resulted from dorsal root avulsions from the conus medullaris. In 7 of the 8 patients, the mechanism of injury was a motor vehicle accident; all 7 sustained severe pelvic trauma. Seven of the 8 patients remained pain-free, off all narcotics, with an average follow-up of 33 months. All patients had DREZ lesions of the conus performed by radiofrequency techniques.

Conus medullaris nerve root avulsions.

The association of avulsive lesions and pain has been well established in avulsions of the brachial plexus from the cervical spinal cord, but avulsive lesions of the conus medullaris have not previously been recognized or documented by direct observation. Six patients with intractable lower-extremity pain due to avulsion of nerve roots from the conus medullaris were treated by thoracolumbar laminectomy and dorsal root entry zone (DREZ) lesions. Patients with avulsion of lumbosacral roots from the conus medullaris have a characteristic clinical presentation. They are usually young men who, as a result of a motorcycle accident, have suffered multiple pelvic or long-bone fractures or traumatic amputation of part of the lower extremity. Early in their course there is pain not directly attributable to the injured part. The pain is described as intense and burning, with episodic radiation and electric shock-like sensations in the injured or phantom limb. If the leg is intact, there is usually a dermatomal pattern to the distribution of the pain and neurological deficit. A myelogram often reveals a traumatic pseudomeningocele similar to those seen in the cervical region after avulsion of the brachial plexus. Surgical exploration of the conus medullaris usually reveals the extent of nerve root avulsion, and an appropriate DREZ operation can be performed.

Nucleus caudalis DREZ lesions for facial pain.

The records of the first 18 patients with intractable facial pain treated with nucleus caudalis dorsal root entry zone lesions were reviewed. The pain etiology varied but the largest group was that of post-herpetic neuralgia. Within the immediate postoperative period 90% of patients had satisfactory pain relief in comparison to 58% on subsequent follow-up. Seventy-one percent of those with post-herpetic neuralgia had satisfactory relief on subsequent follow-up. Favorable results tended to correlate with a lesser preoperative sensory deficit, pain restricted to trigeminal distributions and pain of a burning or lancinating/penetrating quality.