Outcome after surgical treatment of progressive posttraumatic cystic myelopathy.

OBJECT: Progressive posttraumatic cystic myelopathy (PPCM) can occur after an injury to the spinal cord. Traditional treatment of PPCM consists of inserting a shunt into the cyst. However, some authors have advocated a more pathophysiological approach to this problem. The authors of the present study describe their surgical treatment protocol and outcome in a series of patients with syringomyelia. METHODS: Medical records of 34 patients undergoing surgical treatment for PPCM were reviewed. Laminectomies and intraoperative ultrasonography were performed. In patients without focal tethering of the spinal cord and in whom only a confluent cyst had been revealed on ultrasonography, a syringosubarachnoid shunt was inserted; in those with both tethering and a confluent cord cyst, an untethering procedure was performed first. When a significant reduction (>50%) in the size of the cyst was shown after the untethering procedure, no shunt was inserted. When no changes in cyst size were demonstrated on ultrasonography, a short syringosubarachnoid shunt was used. The mean follow-up period was 28.7 months (range 12-102 months). The interval between the mechanism of injury and the operation ranged from 5 months to 37 years (mean 11 years). Pain was the most frequent symptom, which was followed by motor deterioration and spasticity. Postoperative improvement was noted in 55% of patients who experienced motor function deterioration and in 53% of those who demonstrated worsening spasticity. In 14 of 18 patients with an associated tethered spinal cord, tethering alone caused significant collapse of the cyst. Postoperative magnetic resonance imaging demonstrated cyst collapse in 92% of patients who had undergone untethering alone and in 93% of those who underwent syringosubarachnoid shunt placement. Treatment failure was observed in 7% of the former group and in 13% of the latter. CONCLUSIONS: Posttraumatic cystic myelopathy can occur with or without the presence of tethered cord syndrome. Intraoperative ultrasonography can readily demonstrate this distinction to aid in surgical decision making. Untethering alone in patients with tethered cord syndrome and cyst formation can reduce the cyst size and alleviate symptoms and signs of posttraumatic cystic myelopathy in the majority of these cases. Untethering procedures in which duraplasty is performed to expand the subarachnoid space may be a more physiologically effective way of treating tethered cord with associated syringomyelia.

Diagnostic and surgical management of spinal dural arteriovenous fistulas.

OBJECTIVE: A retrospective review was conducted to compare magnetic resonance (MR) and conventional spinal angiographic images and to investigate the outcome of our treatment protocol for patients with spinal dural arteriovenous fistulas (DAVFs). MATERIALS AND METHODS: Nine patients with a diagnosis of DAVF based on clinical myelopathy and preoperative MR imaging (MRI) and MR angiography (MRA) findings were treated at our institution by the senior author (BAG). All nine patients initially presented with progressive myelopathy. Preoperative MRI revealed T2-weighted signal abnormalities in all patients, and MRA was diagnostic in all patients. Each patient underwent a laminectomy and ligation of the arterialized draining vein. Selective spinal angiograms were used to confirm the level of fistula immediately before the surgical procedure was performed and to document complete obliteration after clip ligation of the medullary draining vein. Follow-up MRI and MRA were performed approximately 2 months postoperatively. RESULTS: MRI T2-weighted signal hyperintensity improved after surgery in all nine patients. Postoperatively, progression of motor weakness and gait difficulty was halted and some improvement was observed in all patients. No patient was neurologically normal, however. To date, there has been no clinical or MRA evidence of recurrence in any patient. CONCLUSION: Preoperative MRA and intraoperative spinal x-ray angiography present as an effective combination for diagnosing and intraoperatively confirming DAVF. Both T1-weighted enhancement and T2-weighted signal hyperintensity on MR images improved after the obliteration of the DAVFs and correlated with clinical improvement in all nine patients. MRA provides adequate visualization and localization of spinal DAVFs and may serve as a useful noninvasive tool for diagnosing and following patients with spinal DAVFs in the future.

Surgical treatment of spinal ependymoma and post-operative radiotherapy.

INTRODUCTION: With the advances in microsurgical and monitoring techniques, spinal ependymomas are gross totally resected more frequently. The use of adjuvant radiotherapy has become questionable with gross total resection and its role for residual neoplasm need to be redefined. A retrospective analysis of a series of patients was carried out to investigate our clinical outcome and selected use of post-operative radiotherapy. CLINICAL MATERIALS AND METHODS: Between July 1990 and May 1995, nineteen patients [M : F = 12 : 7; age range: 21 to 71 years] with a spinal ependymoma were treated at University of Miami by the senior author. (BAG) Pre-operative MRI diagnosed the intraspinal tumor, and pathology reports demonstrated that each patient had a histologically confirmed ependymoma. At the time of diagnosis, the most common symptoms presented were pain (in 16 patients = 84.2%). The pattern of progression of clinical symptoms was directly related to the location of the tumor. Each patient had an MRI immediately after surgery, approximately 6 months post-operatively, and then annually. RESULTS: All 19 patients underwent intradural microsurgical exploration with an attempted gross total resection (achieved in 16 patients = 79%) of the ependymoma through a posterior approach. Direct neural tissue stimulation halted further resection in 2 patients with questionable tumor margins. Radiation therapy was employed as a surgical adjunct in 3 patients (15.8%) because of possible residual tumor. All patients were followed up postoperatively for an average of 50.6 months (range 6 months to 6 years). All patients are surviving to date. Surgical resection of these tumors led to significant alleviation of pre-operative symptom. There has been no radiographic evidence of tumor recurrence or growth in any patient to date. CONCLUSION: Surgical resection of spinal ependymoma leads to significant improvement of pre-operative symptoms. Surgical removal alone, with an attempt to grossly resect the tumor, should be the treatment of choice, with careful clinical and radiographic follow-up. Radiation therapy should only be considered as a surgical adjunct where gross total resection is not achieved.

Safety and stability of open-door cervical expansive laminoplasty.

Cervical expansive laminoplasty has been utilized for over 20 years. This retrospective analysis investigated the safety and incidence of postoperative instability of patients undergoing a modified expansive laminoplasty. One hundred five patients underwent a modified cervical expansive laminoplasty and had at least a 6-month follow-up. These 105 patients were followed for a mean of 18.6 months (range 6-89 months). All patients remained in a rigid cervical collar for 8-12 weeks after the laminoplasty. Postoperative cervical plain radiographs were obtained on postoperative day 1, an average of 9.6 weeks postoperatively (range 8-12 weeks) and an average of 10.1 months (range 6-12 months) postoperatively. Thirty-five patients underwent further radiographs >18 months postoperatively. Laminoplasty was performed in 82 patients with progressive cervical spondylotic myelopathy, 4 patients with ossification of the posterior longitudinal ligament, 7 patients for posterior approach to a cervical neoplasm, and 12 patients for early posttraumatic decompression. The canal/vertebral body ratio showed a significant increase from 0.78 to 1.02 (paired t test, p < 0.001). Postoperatively, no incidence of graft dislodgement or segmental instability was diagnosed in any patient. Modified open-door expansive laminoplasty is an effective way of expanding the spinal canal. Its associated low incidence of postoperative instability and kyphotic deformity should make this procedure a desirable substitute for cervical laminectomy under many circumstances.