Narayan Sundaresan

A novel classification system for spinal instability in neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology Study Group.

Study Design. Systematic review and modified Delphi technique. Objective. To use an evidence-based medicine process using the best available literature and expert opinion consensus to develop a comprehensive classification system to diagnose neoplastic spinal instability. Summary of Background Data. Spinal instability is poorly defined in the literature and presently there is a lack of guidelines available to aid in defining the degree of spinal instability in the setting of neoplastic spinal disease. The concept of spinal instability remains important in the clinical decision-making process for patients with spine tumors. Methods. We have integrated the evidence provided by systematic reviews through a modified Delphi technique to generate a consensus of best evidence and expert opinion to develop a classification system to define neoplastic spinal instability. Results. A comprehensive classification system based on patient symptoms and radiographic criteria of the spine was developed to aid in predicting spine stability of neoplastic lesions. The classification system includes global spinal location of the tumor, type and presence of pain, bone lesion quality, spinal alignment, extent of vertebral body collapse, and posterolateral spinal element involvement. Qualitative scores were assigned based on relative importance of particular factors gleaned from the literature and refined by expert consensus. Conclusion. The Spine Instability Neoplastic Score is a comprehensive classification system with content validity that can guide clinicians in identifying when patients with neoplastic disease of the spine may benefit from surgical consultation. It can also aid surgeons in assessing the key components of spinal instability due to neoplasia and may become a prognostic tool for surgical decision-making when put in context with other key elements such as neurologic symptoms, extent of disease, prognosis, patient health factors, oncologic subtype, and radiosensitivity of the tumor.

Spinal Instability Neoplastic Score: An Analysis of Reliability and Validity From the Spine Oncology Study Group

PURPOSE Standardized indications for treatment of tumor-related spinal instability are hampered by the lack of a valid and reliable classification system. The objective of this study was to determine the interobserver reliability, intraobserver reliability, and predictive validity of the Spinal Instability Neoplastic Score (SINS). METHODS Clinical and radiographic data from 30 patients with spinal tumors were classified as stable, potentially unstable, and unstable by members of the Spine Oncology Study Group. The median category for each patient case (consensus opinion) was used as the gold standard for predictive validity testing. On two occasions at least 6 weeks apart, each rater also scored each patient using SINS. Each total score was converted into a three-category data field, with 0 to 6 as stable, 7 to 12 as potentially unstable, and 13 to 18 as unstable. RESULTS The κ statistics for interobserver reliability were 0.790, 0.841, 0.244, 0.456, 0.462, and 0.492 for the fields of location, pain, bone quality, alignment, vertebral body collapse, and posterolateral involvement, respectively. The κ statistics for intraobserver reliability were 0.806, 0.859, 0.528, 0.614, 0.590, and 0.662 for the same respective fields. Intraclass correlation coefficients for inter- and intraobserver reliability of total SINS score were 0.846 (95% CI, 0.773 to 0.911) and 0.886 (95% CI, 0.868 to 0.902), respectively. The κ statistic for predictive validity was 0.712 (95% CI, 0.676 to 0.766). CONCLUSION SINS demonstrated near-perfect inter- and intraobserver reliability in determining three clinically relevant categories of stability. The sensitivity and specificity of SINS for potentially unstable or unstable lesions were 95.7% and 79.5%, respectively.

Surgery for solitary metastases of the spine: rationale and results of treatment.

Study Design. A spine tumor database of patients with solitary sites of spine involvement from solid tumors was retrospectively reviewed. Objectives. To analyze the long-term survival, neurologic outcome, and results of surgery in a well-defined subset of patients who had spinal metastases with epidural extension to define future treatment strategies. Summary of Background Data. Currently accepted indications for surgical treatment of spinal metastases include histologic diagnosis, neurologic palliation in those who have failed prior irradiation, and spinal stabilization. In all others, external irradiation is considered the mainstay of therapy. Several studies have shown that prior irradiation increases the frequency of complications from surgery and affects functional outcome. Methods. A retrospective review of 80 consecutive patients with solitary sites of spine involvement from solid tumors with varying degrees of epidural extension was performed. Complete clinical and radiologic follow-up assessment was available for all the patients. Clinical parameters, neurologic grade, preoperative pain, radiologic evaluation, and outcome measures were analyzed. Survival analysis was performed using the Kaplan–Meier product limit method, and differences between subgroups were analyzed using &khgr;2. Prognostic factors for long-term survival also were evaluated. Results. The overall median survival after surgery was 30 months, with 18% surviving 5 years or more. Survival varied by tumor type, with the best prognosis noted in patients with breast or kidney cancer. The surgical morbidity was significantly higher in those receiving prior irratiation (P < 0.03), and the local recurrence rate also increased in patients who had received prior irradiation. Conclusions. Patients with solitary sites of spine involvement from solid tumors represent a biologically favorable subgroup with potential for long-term survival. In this group, complete surgical excision before irradiation should be considered to increase the prospects of long-term palliation and possible cure.

Surgical treatment of spinal cord compression from epidural metastasis.

PURPOSE A retrospective study of the results of neoplastic cord compression was undertaken to determine the effectiveness of surgical treatment and to assess quality of life in patients undergoing extensive procedures with potential morbidity. PATIENTS AND METHODS Over a 5-year period (1989 to 1993), a total of 110 patients underwent surgery. Fifty-five patients (50%) had undergone prior treatment, including 47 (43%) who had failed to respond to prior irradiation (RT). Before surgery, 48 patients (44%) were nonambulatory, with severe paresis being present in 20. Surgery included staged anterior-posterior resections in 53 patients (48%), anterior resections in 33 (30%), and posterior resection in six (5%), all of whom required spinal instrumentation for reconstruction; only 18 patients underwent resection without instrumentation. RESULTS Postoperatively, 90 patients (82%) were improved, both in terms of pain relief and ambulatory status. Fifty-three patients (48%) experienced postoperative complications, related statistically to the following three factors: age over 65 years, prior treatment, and presence of paraparesis. The overall median survival duration was 16 months, with 46% alive at 2 years. Apart from primary tumor, the presence of preoperative paraparesis had the most significant impact on survival. CONCLUSION Our data suggest that the effective surgical treatment of neoplastic compression requires anterior-posterior resection in most patients to achieve the goal of total tumor resection, with the majority requiring instrumentation. Long-term survival is feasible in a subset of patients with this aggressive surgical approach.

Combined treatment of osteosarcoma of the spine.

We reviewed the clinical features and results of treatment in 24 patients with osteogenic sarcoma of the spine treated over a 35-year period. There were 14 male and 10 female patients 13 to 71 years old. The tumor arose de novo in 13 patients and was secondary to other conditions in 11. All patients presented with pain, and 16 (67%) had neurological deficits. Patients were divided into two treatment groups. Thirteen patients treated from 1949 to 1977 usually underwent limited tumor resection and external radiation therapy. The second group, 11 patients treated from 1978 to 1984, underwent more aggressive surgical resection and received combination chemotherapy as well as local radiation to the tumor bed. In the second group, there were 5 long term survivors, and only 1 patient developed metastatic disease while on therapy. Failure to obtain local control was the major cause of treatment failure. Complete surgical resection of the tumor by spondylectomy and combination chemotherapy offer the best prospect for cure of osteogenic sarcoma of the spine.

Spondylectomy for malignant tumors of the spine.

Spondylectomy is the complete surgical removal of all parts of one or more vertebrae above the sacrum. We report our initial experience with spondylectomy in eight patients with malignant tumors of the spine operated on over a 7-year period (1980 to 1986). Four patients had primary neoplasms of the spine, and four others had solitary metastases to the vertebrae. Following surgery, five patients underwent radiation therapy (RT) and chemotherapy depending on histology of the tumor. Radiographic confirmation of tumor resection was obtained on all patients. Pain relief was noted in all patients, and six patients with preoperative neurological deficits improved. There was no surgical mortality, and one patient developed wound dehiscence following surgery. Six of the eight patients are alive with a median follow-up of 36 months, and local control was achieved in six of the eight patients. These preliminary data suggest that malignant tumors of the spine can be completely resected using a staged approach. In potentially responsive tumors, systemic chemotherapy is recommended between the two operations to reduce the risk of systemic dissemination.

Surgical treatment of spinal cord compression in kidney cancer.

Forty-three patients with renal-cell carcinoma underwent treatment for spinal cord compression over a 7-year period. Of these, 32 patients underwent surgery, while 11 patients underwent radiation alone. Before operation, 25 patients had relapsed following prior radiation, while seven others received postoperative radiation. A more aggressive surgical approach, tailored to the site of compression within the spinal canal, was used with the majority undergoing gross total tumor resection by an anterior approach. Immediate stability of the spine was achieved with methyl-methacrylate reconstruction of the resected segments. Preoperative spinal angiography with embolization of hypervascular tumors was carried out in eight patients. Patient parameters in the surgical and irradiated groups were comparable, except that a greater proportion of the radiation alone group had more than one organ system involved (64% v 44%). The median survival of the surgically treated patients was 13 months, compared with 3 months for those treated by radiation alone. In addition, a greater proportion of the surgically treated patients were benefitted neurologically (70%) compared with those treated by radiation (45%). With the development of effective surgical treatment for spinal metastases, early consideration for surgical treatment (before radiation) should be considered in selected patients. Preoperative spinal angiography and embolization are recommended whenever feasible to minimize intraoperative blood loss.

Primary Malignant Tumors of the Spine

Primary malignant tumors of the spine account for less than 5% of primary bone tumors. Data from the SEER program suggest that the most common bone sarcomas are osteosarcoma, chondrosarcoma, Ewings sarcoma, chordoma, and malignant fibrous histiocytoma/fibrosarcoma. During the last two decades, tremendous progress has been made in clinical aspects, surgical approaches, and reconstruction with instrumentation at all levels of the spine. Stabilization procedures, including vertebroplasty and kyphoplasty, have further allowed palliation of pain and symptom relief from compression fractures. Improved radiation techniques have offered the potential for improved local control. This article reviews the changes in surgical philosophy in the management of malignant spinal tumors during the past two decades.

Craniofacial resections for tumors involving the base of the skull

Over a 10 year period, 42 patients with tumors involving the base of the skull underwent operation at our institution. Twenty-six patients had tumors involving the anterior fossa and cribriform plate, 3 patients had tumors involving the anterior fossa and orbit, 3 patients had invasion of the middle fossa, 5 patients had invasion of the temporal bone, and 5 patients had invasion of the clivus. A detailed analysis of the 26 patients who underwent craniofacial resection for tumors invading the anterior fossa cribriform plate region has been presented. Histologic studies revealed epithelial tumors in 18 patients, sarcoma in 6 patients, melanoma in one patient, and ossifying fibroma in one patient. The median survival in this group of patients was 60 months. Survival was influenced by histologic diagnosis. Malignant tumors involving the base of the skull can be successfully resected using a craniofacial approach with minimum morbidity and acceptable operative mortality as demonstrated in this experience. Unfavorable prognostic factors included massive intracranial extension, high grade tumor, and previous treatment failure.

Reoperation for brain metastases.

We report the results of reoperation for brain metastases in 21 patients with recurrent tumors following initial successful resection. The tumor recurrences were local (original site) in 14 patients, and occurred at other sites in the brain in the remaining seven. Time to CNS recurrence ranged from 3 to 30 months. At time of repeat craniotomy, disease was limited to the CNS in 12 (57%) of the patients. Median survival following second craniotomy was 9 months, and the actuarial 2-year survival was 25%. Neurological improvement was seen in two thirds of the patients; the median duration of neurological improvement was 6 months. There was no mortality, and only one patient developed increased deficit following surgery. We conclude that repeat resection of brain metastases is an important therapeutic option in selected patients, and should be considered in symptomatic patients with accessible mass lesions before the use of other experimental treatment.