Indro Chakrabarti

Surgical management of primary and metastatic sarcoma of the mobile spine

OBJECT Sarcomas of the spine are a challenging problem due to their frequent and extensive involvement of multiple spinal segments and high recurrence rates. Gross-total resection to negative margins, with preservation of neurological function and palliation of pain, is the surgical goal and may be achieved using either intralesional resection or en bloc excision. The authors report outcomes of surgery for primary and metastatic sarcomas of the mobile spine in a large patient series. METHODS A retrospective review of patients undergoing resection for sarcomas of the mobile spine between 1993 and 2005 was undertaken. Sarcomas were classified by histology study results and as either primary or metastatic. Details of the surgical approach, levels of involvement, and operative complications were recorded. Outcome measures included neurological function, palliation of pain, local recurrence, and overall survival. RESULTS Eighty patients underwent 110 resections of either primary or metastatic sarcomas of the mobile spine. Twenty-nine lesions were primary sarcomas (36%) and 51 were metastatic sarcomas (64%). Intralesional resections were performed in 98 surgeries (89%) and en bloc resections were performed in 12 (11%). Median survival from surgery for all patients was 20.6 months. Median survival for patients with a primary sarcoma of the spine was 40.2 months and was 17.3 months for patients with a metastatic sarcoma. Predictors of improved survival included a chondrosarcoma histological type and a better preoperative functional status, whereas osteosarcoma and a high-grade tumor were negative influences on survival. Multivariate analysis showed that only a high-grade tumor was an independent predictor of shorter overall survival. American Spinal Injury Association scale grades were maintained or improved in 97% of patients postoperatively, and there was a significant decrease in pain scores postoperatively. No significant differences in survival or local recurrence rates between intralesional or en bloc resections for either primary or metastatic spine sarcomas were found. CONCLUSIONS Surgery for primary or metastatic sarcoma of the spine is associated with an improvement in neurological function and palliation of pain. The results of this study show a significant difference in patient survival for primary versus metastatic spine sarcomas. The results do not show a statistically significant benefit in survival or local recurrence rates for en bloc versus intralesional resections for either metastatic or primary sarcomas of the spine, but this may be due to the small number of patients undergoing en bloc resections.

En bloc resection of a multilevel high-cervical chordoma involving C-2: new operative modalities: technical note.

En bloc resection of cervical chordomas has led to longer survival rates but has resulted in significant morbidities from the procedure, especially when the tumor is multilevel and located in the high-cervical (C1-3) region. To date, there have been only 5 reported cases of multilevel en bloc resection of chordomas in the high-cervical spine. In this technical report the authors describe a sixth case. A complete spondylectomy was performed at C-2 and C-3 with spinal reconstruction and stabilization, using several new modalities that were not used in the previous cases. The use of 1) preoperative endovascular sacrificing of the vertebral artery, 2) CT image-guidance, 3) an ultrasonic aspirator for skeletonizing the vertebral artery, and 4) the custom design of an anterior cage all contributed to absence of intraoperative or long-term (20 months) hardware failure and pseudarthrosis.

The use of intraoperative navigation for complex upper cervical spine surgery

Imaging guidance using intraoperative CT (O-arm surgical imaging system) combined with a navigation system has been shown to increase accuracy in the placement of spinal instrumentation. The authors describe 4 complex upper cervical spine cases in which the O-arm combined with the StealthStation surgical navigation system was used to accurately place occipital screws, C-1 screws anteriorly and posteriorly, C-2 lateral mass screws, and pedicle screws in C-6. This combination was also used to navigate through complex bony anatomy altered by tumor growth and bony overgrowth. The 4 cases presented are: 1) a developmental deformity case in which the C-1 lateral mass was in the center of the cervical canal causing cord compression; 2) a case of odontoid compression of the spinal cord requiring an odontoidectomy in a patient with cerebral palsy; 3) a case of an en bloc resection of a C2-3 chordoma with instrumentation from the occiput to C-6 and placement of C-1 lateral mass screws anteriorly and posteriorly; and 4) a case of repeat surgery for a non-union at C1-2 with distortion of the anatomy and overgrowth of the bony structure at C-2.

Surgical treatment of sacral metastases: Indications and results: Clinical article

OBJECT Hematogenous metastases to the sacrum can produce significant pain and lead to spinal instability. The object of this study was to evaluate the palliative benefit of surgery in patients with these metastases. METHODS The authors retrospectively reviewed all cases involving patients undergoing surgery for metastatic disease to the sacrum at a single tertiary cancer center between 1993 and 2005. RESULTS Twenty-five patients (21 men, 4 women) were identified as having undergone sacral surgery for hematogenous metastatic disease during the study period. Their median age was 57 years (range 25-71 years). The indications for surgery included palliation of pain (in 24 cases), need for diagnosis (in 1 case), and spinal instability (in 3 cases). The most common primary disease was renal cell carcinoma. Complications occurred in 10 patients (40%). The median overall survival was 11 months (95% CI 5.4-16.6 months). The median time from the initial diagnosis to the diagnosis of metastatic disease in the sacrum was 14 months (95% CI 0.0-29.3 months). The numerical pain scores (scale 0-10) were improved from a median of 8 preoperatively to a median of 3 postoperatively at 90 days, 6 months, and 1 year (p < 0.01). Postoperative modified Frankel grades improved in 8 cases, worsened in 3 (due to disease progression), and remained unchanged in 14 (p = 0.19). Among patients with renal cell carcinoma, the median overall survival was better in those in whom the sacrum was the sole site of metastatic disease than in those with multiple sites of metastatic disease (16 vs 9 months, respectively; p = 0.053). CONCLUSIONS Surgery is effective to palliate pain with acceptable morbidity in patients with metastatic disease to the sacrum. In the subgroup of patients with renal cell carcinoma, those with the sacrum as their solitary site of metastatic disease demonstrated improved survival.

The use of flexion-extension magnetic resonance imaging for evaluating signal intensity changes of the cervical spinal cord

The authors present 2 cases involving patients who presented with myelopathy. Magnetic resonance imaging of the cervical spine showed spinal cord signal changes on T2-weighted images without any spinal cord compression. Flexion-extension plain radiographs of the spine showed no instability. Dynamic MR imaging of the cervical spine, however, showed spinal cord compression on extension. Compression of the spinal cord was caused by dynamic anulus bulging and ligamentum flavum buckling. This report emphasizes the need for dynamic MR imaging of the cervical spine for evaluating spinal cord changes on neutral position MR imaging before further workup for other causes such as demyelinating disease.