Abstracts of the 2013 Annual Meeting of the AANS/CNS Section on Disorders of the Spine and Peripheral Nerves
Phoenix, Arizona • March 6–9, 2013
Daryl R. Fourney, Laurence D. Rhines, Stephen J. Hentschel, John M. Skibber, Jean-Paul Wolinsky, Kristin L. Weber, Dima Suki, Gary L. Gallia, Ira Garonzik, and Ziya L. Gokaslan
En bloc resection with adequate margins is associated with the highest probability of long-term tumor control or cure in most cases of primary sacral malignancies. The authors present their experience with a systematic approach to these lesions. They provide a novel classification of surgical techniques based on the level of nerve root sacrifice and evaluate the functional and oncological outcomes.
Seventy-eight consecutive patients underwent 94 resections of sacral neoplasms at The University of Texas M. D. Anderson Cancer Center in Houston between August 1993 and June 2002. The records of 29 consecutive patients who underwent en bloc resection of primary sacral tumors were retrospectively reviewed. The median follow-up period was 55 months (range 1–103 months). Chordoma was the most frequent tumor type (16 cases). Midline sacral amputation was performed in 25 patients (eight low, four middle, seven high, and five total sacrectomies; one hemicorporectomy). Lateral sacrectomy was undertaken in four patients (two unilateral excisions of the sacroiliac joint and two hemisacrectomies). The surgical margins were wide in 19 cases, marginal in nine, and contaminated in one. The type of sacrectomy correlated with characteristic outcomes with respect to bladder, bowel, and ambulatory functions. Duration of hospital stay was related to the extent of sacrectomy (p = 0.003, Wilcoxon signed-rank test). The median Kaplan—Meier disease-free survival for patients with chordoma was 68 months (95% confidence interval 46–90 months).
Classification of en bloc sacral resection techniques by the level of nerve root transection is useful in predicting postoperative function and the potential for morbidity. Adequate surgical margins should not be compromised to preserve function when they are necessary to affect tumor control.
Stephen J. Hentschel, Allen W. Burton, Daryl R. Fourney, Laurence D. Rhines, and Ehud Mendel
Object. The purpose of this study was to examine a group of patients with cancer who underwent a vertebroplasty or a kyphoplasty for a vertebral body (VB) fracture, even though the procedure may have been considered contraindicated based on previous reports in the literature.
Methods. The electronic database maintained by the Departments of Neurosurgery and Anesthesiology—Pain Management at the University of Texas M. D. Anderson Cancer Center was searched for patients who underwent vertebroplasty or kyphoplasty between January 2001 and July 2003. The criteria defining a contraindicated procedure were based on a review of the literature. Group I consisted of patients who did not undergo a contraindicated vertebroplasty or kyphoplasty, whereas Group II consisted of patients who underwent one of these procedures even though it may have been considered contraindicated.
There were 53 patients with fractures at 132 levels who met the criteria for the study. Of these, 17 patients with fractures at 18 levels (14% of total) were considered to have undergone a contraindicated vertebroplasty or kyphoplasty (Group II). There were 12 complications (11%) in the 114 levels in Group I and seven complications (39%) in the 18 levels in Group II (p = 0.03). The most common complication was cement extrusion from the anterior VB that did not involve the venous system. No patient required an open surgical procedure to remove extruded cement.
Conclusions. Vertebroplasty and kyphoplasty appear to be safe and effective in the setting of severe back pain caused by VB fracture that is unresponsive to other therapies, even in the presence of relative contraindications to the procedures.
Case report and description of operative technique
Laurence D. Rhines, Daryl R. Fourney, Abdolreza Siadati, Ian Suk, and Ziya L. Gokaslan
✓ Chordomas are locally aggressive neoplasms with an extremely high propensity to recur locally following resection, despite adjuvant therapy. This biological behavior has led most authors to conclude that en bloc resection provides the best chance for the patient's prolonged disease-free survival and possible cure.
The authors present a case of an extensive upper cervical chordoma treated by en bloc resection, reconstruction, and long-segment stabilization. Total spondylectomy of C2–4 with sacrifice of the right C2–4 nerve roots and a segment of the right vertebral artery was performed. The inherent anatomical complexities of en bloc resection in the upper cervical spine are discussed. To the authors' knowledge, this represents the first report of an en bloc resection for multilevel cervical chordoma.
Case report and review of the literature
Daryl R. Fourney, Abdolreza Siadati, Janet M. Bruner, Ziya L. Gokaslan, and Laurence D. Rhines
✓ Several rare histological variants of ependymoma have been described. The authors report on a patient in whom cervical spinal cord astrocytoma was originally diagnosed after evaluation of a limited biopsy specimen. More abundant tissue obtained during gross-total resection included areas of well-differentiated ependymoma. The histological features of the tumor were extremely unusual, with a major component of pleomorphic giant cells. Its histological, immunohistochemical, and electron microscopic features, however, were consistent with ependymoma. Only two cases of terminal filum and two of supratentorial giant cell variant of ependymoma have been reported. To the authors' knowledge, this represents the first case of giant cell ependymoma of the spinal cord. The clinical significance is the potential for misdiagnosis with anaplastic (gemistocytic) astrocytoma, especially in cases in whom limited biopsy samples have been obtained.
Daryl R. Fourney, Julie E. York, Zvi R. Cohen, Dima Suki, Laurence D. Rhines, and Ziya L. Gokaslan
Object. The treatment of atlantoaxial spinal metastases is complicated by the region's unique biomechanical and anatomical characteristics. Patients most frequently present with pain secondary to instability; neurological deficits are rare. Recently, some authors have performed anterior approaches (transoral or extraoral) for resection of upper cervical metastases. The authors review their experience with a surgical strategy that emphasizes posterior stabilization of the spine and avoidance of poorly tolerated external orthoses such as the rigid cervical collar or halo vest.
Methods. The authors performed a retrospective review of 19 consecutively treated patients with C-1 or C-2 metastases who underwent surgery at The University of Texas M. D. Anderson Cancer Center between 1994 and 2001.
Visual analog pain scores were reduced at 1 and 3 months (p < 0.005, Wilcoxon signed-rank test); however, evaluation of pain at 6 months and 1 year was limited by the remaining number of surviving patients. Analgesic medication consumption was unchanged. There were no cases of neurological decline or sudden death secondary to residual or recurrent atlantoaxial disease during the follow-up period. One patient underwent revision of hardware at 11 months. The mean follow-up period was 8 months (range 1–32 months). Median survival determined by Kaplan—Meier analysis was 6.1 months (95% confidence interval 2.99–9.21).
Conclusions. Occipitocervical stabilization provided durable pain relief and preservation of ambulatory status over the remaining life span of patients. Because of the palliative goals of surgery, the authors have not found an indication for anterior-approach tumor resection in these patients. Successful stabilization obviates the need for an external orthosis.
Daryl R. Fourney, Donald F. Schomer, Remi Nader, Jennifer Chlan-Fourney, Dima Suki, Kamran Ahrar, Laurence D. Rhines, and Ziya L. Gokaslan
Object. The current North American experience with minimally invasive vertebro- and kyphoplasty is largely limited to the treatment of benign osteoporotic compression fractures. The objective of this study was to assess the safety and efficacy of these procedures for painful vertebral body (VB) fractures in cancer patients.
Methods. The authors reviewed a consecutive group of cancer patients (21 with myeloma and 35 with other primary malignancies) undergoing vertebro- and kyphoplasty at their institution. Ninety-seven (65 vertebro- and 32 kyphoplasty) procedures were performed in 56 patients during 58 treatment sessions. The mean patient age was 62 years (± 13 years [standard deviation]) and the median duration of symptoms was 3.2 months. All patients suffered intractable spinal pain secondary to VB fractures.
Patients noted marked or complete pain relief after 49 procedures (84%), and no change after five procedures (9%); early postoperative Visual Analog Scale (VAS) pain scores were unavailable in four patients (7%). No patient was worse after treatment. Reductions in VAS pain scores remained significant up to 1 year (p = 0.02, Wilcoxon signed-rank test). Analgesic consumption was reduced at 1 month (p = 0.03, Wilcoxon signed-rank test). Median follow-up length was 4.5 months (range 1 day–19.7 months). Asymptomatic cement leakage occurred during vertebroplasty at six (9.2%) of 65 levels; no cement extravasation was seen during kyphoplasty. There were no deaths or complications related to the procedures. The mean percentage of restored VB height by kyphoplasty was 42 ± 21%.
Conclusions. Percutaneous vertebro- and kyphoplasty provided significant pain relief in a high percentage of patients, and this appeared durable over time. The absence of cement leakage—related complications may reflect the use of 1) high-viscosity cement; 2) kyphoplasty in selected cases; and 3) relatively small 3volume injection. Precise indications for these techniques are evolving; however, they are safe and feasible in well-selected patients with refractory spinal pain due to myeloma bone disease or metastases.
Case report and description of operative technique
Zvi R. Cohen, Daryl R. Fourney, Rex A. Marco, Laurence D. Rhines, and Ziya L. Gokaslan
✓ The authors describe a technique for total spondylectomy for lesions involving the cervical spine. The method involves separately staged anterior and posterior approaches and befits the unique anatomy of the cervical spine. The procedure is described in detail, with the aid of radiographs, intraoperative photographs, and illustrations. Unlike in the thoracic and lumbar spine—for which methods of total en bloc spondylectomy have previously been described—a strictly en bloc resection is not possible in the cervical spine because of the need to preserve the vertebral arteries and the nerve roots supplying the upper limbs. Although the resection described in this case is by definition intralesional, it is oncologically sound, given the development of effective neoadjuvent chemotherapeutic regimens for osteosarcoma.
Daryl R. Fourney, Dima Abi-Said, Laurence D. Rhines, Garrett L. Walsh, Frederick F. Lang, Ian E. McCutcheon, and Ziya L. Gokaslan
Object. Thoracic or lumbar spine malignant tumors involving both the anterior and posterior columns represent a complex surgical problem. The authors review the results of treating patients with these lesions in whom surgery was performed via a simultaneous anterior—posterior approach.
Methods. The hospital records of 26 patients who underwent surgery via simultaneous combined approach for thoracic and lumbar spinal tumors at our institution from July 1994 to March 2000 were reviewed. Surgery was performed with the patients in the lateral decubitus position for the procedure. The technical details are reported.
The mean survival determined by Kaplan—Meier analysis was 43.4 months for the 15 patients with primary malignant tumors and 22.5 months for the 11 patients with metastatic spinal disease. At 1 month after surgery, 23 (96%) of 24 patients who complained of pain preoperatively reported improvements (p < 0.001, Wilcoxon signed-rank test), and eight (62%) of 13 patients with preoperative neurological deficits were functionally improved (p = 0.01). There were nine major complications, five minor complications, and no deaths within 30 days of surgery. Two patients (8%) later underwent surgery for recurrent tumor.
Conclusions. The simultaneous anterior—posterior approach is a safe and feasible alternative for the exposure tumors of the thoracic and lumbar spine that involve both the anterior and posterior columns. Advantages of the approach include direct visualization of adjacent neurovascular structures, the ability to achieve complete resection of lesions involving all three columns simultaneously (optimizing hemostasis), and the ability to perform excellent dorsal and ventral stabilization in one operative session.