Outcomes following surgical intervention for impending and gross instability caused by multiple myeloma in the spinal column.

Object: Multiple myeloma is the most common primary tumor of the spine and is the most common primary malignant tumor of bone. Although spinal myeloma is classically a radiosensitive lesion, clinical or radiographic signs of instability merit surgical intervention. The authors present the epidemiology, surgical indications, and outcome data of a series of consecutive cases involving 31 surgically treated patients with diagnoses of multiple myeloma and plasmacytoma of the spine (the largest such series reported to date).

Methods: Surgical instability was the criterion for operative intervention in this patient cohort. The Spinal Instability Neoplastic Score (SINS) was used to make this assessment of instability. The cases were analyzed using location of the lesion, spinal levels involved, Frankel score, adjuvant therapy, functional outcome, and patient survival.

Results: All patients undergoing surgical intervention were determined to have indeterminate or gross spinal column instability according to SINS criteria. The median survival was 78.9 months. No significant difference in survival was seen for patients with higher SINS scores or for older patients (> 55 years). There was a statistically significant difference in survival benefit observed for patients receiving chemotherapy and radiation versus radiation alone as an adjuvant to surgery (p = 0.02).

Conclusions: In this 10-year analysis, the authors report outcomes of surgical intervention for patients with indeterminate or gross spinal instability due to multiple myeloma and plasmacytoma of the spine with improved neurological function following surgery and low rates of instrumentation failure.