Faculty Bibliography

PURPOSE/OBJECTIVE:Advances in stereotactic radiosurgery have improved local control of spine metastases, but local failure is still a problem and repeat irradiation is limited by normal tissue tolerance. A novel high-dose-rate (HDR) brachytherapy technique has been developed to treat these previously irradiated lesions. METHODS AND MATERIALS/METHODS:Five patients with progressive disease at previously irradiated sites in the spine who were not amenable to further external beam radiation were treated. Catheters were placed intraoperatively in 2 patients and percutaneously implanted in 3 patients with image-guided techniques. Conformal plans were generated to deliver dose to target tissues and spare critical structures. Patients received single-fraction treatment using HDR iridium-192 brachytherapy. RESULTS:Median dose was 14 Gy (range, 12-18 Gy) with a median gross total volume D90 of 75% (range, 31-94%); spinal cord/cauda equina dose constraints were met. At a median followup of 9 months, no local progression of disease has been observed. Four patients had reduction in pain 1-4 weeks after treatment. No brachytherapy-related complications have been observed. CONCLUSIONS:Intraoperative and percutaneous iridium-192 HDR spine brachytherapy techniques were not associated with complications or acute toxicity. There has been no local progression at treated sites, and most patients experienced reduction in cancer-related pain.

BACKGROUND:Spinal metastases frequently arise in patients with cancer. Modern oncology provides numerous treatment options that include effective systemic, radiation, and surgical options. We delineate and provide the evidence for the neurologic, oncologic, mechanical, and systemic (NOMS) decision framework, which is used at Memorial Sloan-Kettering Cancer Center to determine the optimal therapy for patients with spine metastases. METHODS:We provide a literature review of the integral publications that serve as the basis for the NOMS framework and report the results of systematic implementation of the NOMS-guided treatment. RESULTS:The NOMS decision framework consists of the neurologic, oncologic, mechanical, and systemic considerations and incorporates the use of conventional external beam radiation, spinal stereotactic radiosurgery, and minimally invasive and open surgical interventions. Review of radiation oncology and surgical literature that examine the outcomes of treatment of spinal metastatic tumors provides support for the NOMS decision framework. Application of the NOMS paradigm integrates multimodality therapy to optimize local tumor control, pain relief, and restoration or preservation of neurologic function and minimizes morbidity in this often systemically ill patient population. CONCLUSION/CONCLUSIONS:NOMS paradigm provides a decision framework that incorporates sentinel decision points in the treatment of spinal metastases. Consideration of the tumor sensitivity to radiation in conjunction with the extent of epidural extension allows determination of the optimal radiation treatment and the need for surgical decompression. Mechanical stability of the spine and the systemic disease considerations further help determine the need and the feasibility of surgical intervention.

BACKGROUND:Notochord-related lesions of the spinal column include benign notochordal cell tumors (BNCTs), ecchordosis physaliphora, both generally considered benign lesions, and chordomas, which represent malignant tumors. The histological similarity of these lesions to the notochord and each other and their strong predilection to the axial skeleton have led to the hypothesis that these lesions represent a continuum of malignant transformation from notochordal remnants, BNCTs, and finally chordomas. OBJECTIVE:To present a cohort of biopsy-proven BNCTs with a description of radiographic features, histology, and follow-up to help elucidate the optimal management of these lesions. METHODS:A retrospective chart review identified 13 patients with notochordal rest lesions confirmed by histology. Histologic inclusion criteria included notochordal features without evidence of septation, myxoid matrix, nuclear atypia, or mitotic figures. Tumors exhibiting evidence of cortical expansion or destruction were excluded. The natural history and histological and radiographic features were examined. RESULTS:Sixteen spinal lesions from 8 patients met the diagnostic criteria for BNCTs, identified on imaging after the patient presented with back pain. Radiographically, all lesions were hypointense on T1-weighted magnetic resonance imaging sequences and hyperintense on T2-weighted and short T1 inversion recovery. The median radiographic follow-up was 21.6 months (range, 8.5-71.2 months). None of the lesions exhibited radiographic or symptomatic progression. CONCLUSION/CONCLUSIONS:Although limited by short follow-up, our series confirms that these lesions may be safely observed without evidence of malignant transformation, which emphasizes the importance of distinction of BNCT from chordoma at diagnosis and the possibility of close follow-up for these lesions instead of aggressive treatment indicated in patients with chordomas.

BACKGROUND:En bloc wide-margin excision significantly decreases the risk of chordoma recurrence. However, a wide surgical margin cannot be obtained in many chordomas because they arise primarily in the sacrum, clivus, and mobile spine. Furthermore, these tumors have shown resistance to fractionated photon radiation at conventional doses and numerous chemotherapies. OBJECTIVE:To analyze the outcomes of single-fraction stereotactic radiosurgery (SRS) in the treatment of chordomas of the mobile spine and sacrum. METHODS:Twenty-four patients with chordoma of the sacrum and mobile spine were treated with high-dose single-fraction SRS (median dose, 2400 cGy). Twenty-one primary and 3 metastatic tumors were treated. Seven patients were treated for postoperative tumor recurrence. In 7 patients, SRS was administered as planned adjuvant therapy, and in 13 patients, SRS was administered as neoadjuvant therapy. All patients had serial magnetic resonance imaging follow-up. RESULTS:The overall median follow-up was 24 months. Of the 24 patients, 23 (95%) demonstrated stable or reduced tumor burden based on serial magnetic resonance imaging. One patient had radiographic progression of tumor 11 months after SRS. Only 6 of 13 patients who underwent neoadjuvant SRS proceeded to surgery. This decision was based on the lack of radiographic progression and the patient's preference. Complications were limited to 1 patient in whom sciatic neuropathy developed and 1 with vocal cord paralysis. CONCLUSION/CONCLUSIONS:High-dose single-fraction SRS provides good tumor control with low treatment-related morbidity. Additional follow-up is required to determine the long-term recurrence risk.

The existing literature on preoperative spine tumor embolization is limited in size of patient cohorts and diversity of tumor histologies. This report presents our experience with preoperative embolization of hypervascular thoracic, lumbar, and sacral spinal column tumors in the largest series to date. We conducted a retrospective review of 228 angiograms and 188 pre-operative embolizations for tumors involving thoracic, lumbar and sacral spinal column. Tumor vascularity was evaluated with conventional spinal angiography and was graded from 0 (same as normal adjacent vertebral body) to 3 (severe tumor blush with arteriovenous shunting). Embolic materials included poly vinyl alcohol (PVA) particles and detachable platinum coils and rarely, liquid embolics. The degree of embolization was graded as complete, near-complete, or partial. Anesthesia records were reviewed to document blood loss during surgery. Renal cell carcinoma (44.2%), thyroid carcinoma (9.2%), and leiomyosarcoma (6.6%) were the most common tumors out of a total of 40 tumor histologies. Hemangiopericytoma had the highest mean vascularity (2.6) of all tumor types with at least five representative cases followed by renal cell carcinoma (2.0) and thyroid carcinoma (2.0). PVA particles were used in 100% of cases. Detachable platinum coils were used in 51.6% of cases. Complete, near-complete, and partial embolizations were achieved in 86.1%, 12.7%, and 1.2% of all cases, respectively. There were no new post-procedure neurologic deficits or other complications with long-term morbidity. The mean intra-operative blood loss for the hypervascular tumors treated with pre-operative embolization was 1745 cc. Preoperative embolization of hypervascular thoracic, lumbar, and sacral spine tumors can be performed with high success rates and a high degree of safety at high volume centers.

OPINION STATEMENT/UNASSIGNED:The management of recurrent chordomas are clinically challenging because of its relentless nature. Local therapy, whether surgery or radiation, are important considerations since local progression of disease results in significant morbidity and locally aggressive treatment is often required. Stereotactic radiosurgery, shown to be very effective for radioresistant histologies, may be an important radiotherapeutic approach for recurrent tumors. Ultimately, the treatment of recurrent chordoma is palliative in intent, thus, enthusiasm for improving local control must be tempered against the possible impact of treatment on quality of life. Judicious use of radiotherapy and surgery can often provide meaningful palliation and local control of recurrences. Systemic treatment options, particularly with targeted molecules have great potential for chordomas in the recurrent setting, as the risk of disseminated disease is higher. The development of tools to help assess potential targets for drug therapy will be crucial. The incorporation of locally aggressive therapy and effective systemic therapy will be critical for the successful management of recurrent chordomas. At present, there is a paucity of published data regarding salvage therapy. Nonetheless, advances in surgical, medical, and radiation oncology are providing new avenues of research and potentially may have significant impact upon successful salvage treatment.

BACKGROUND:Treatment of spinal and intracranial tumors with dural involvement is complicated by radiation tolerance of sensitive structures, especially in the setting of previous treatment. OBJECTIVE:To evaluate whether intraoperative brachytherapy with short-range sources allows therapeutic dose delivery without damaging sensitive structures. METHODS:The median doses of previous treatment were 3000 cGy (range, 1800-7200 cGy) for 8 patients with primary/recurrent and 17 patients with metastatic spinal tumors and 5040 cGy (range, 1300-6040 cGy) for 5 patients with locally recurrent and 2 patients with metastatic intracranial tumors. Patients underwent gross total or maximal resection of the tumor and were then treated with an intraoperative brachytherapy plaque consisting of a flexible silicone film incorporating P. A dose of 1000 cGy was delivered to a depth of 1 mm; the percent depth dose was less than 1% at 4 mm from the prescription depth. Median postoperative radiation doses of 2700 cGy (range, 1800-3000 cGy) were delivered to 15 spinal tumor patients and 3000 cGy (range, 1800-3000 cGy) to 3 intracranial tumor patients. The median follow-up was 4.4 months (range, 2.6-23.3 months) for spinal tumor patients and 5.3 months (range, 0.7-16.2) for intracranial tumor patients. RESULTS:At 6-month follow-up, for all spinal tumor patients, local progression-free survival and overall survival rates were both 83.3% (95% confidence interval [CI]: 62.3%-94.3%); for all intracranial tumor patients, the local progression-free survival rate was 62.5% (95% CI: 23.8%-90.9%) and the overall survival rate was 66.7% (95% CI: 26.7%-92.9%). There were no intraoperative or postoperative complications secondary to radiotherapy. CONCLUSION/CONCLUSIONS:Use of the P brachytherapy plaque is technically simple and not associated with increased risk of complications, even after multiple radiation courses. Local control rates were more than 80% in patients with proven radiation-resistant spinal disease.

STUDY DESIGN/METHODS:A retrospective review. OBJECTIVE:To report our approach and results using a contralateral minimally invasive spinal surgical muscle splitting approach that allows visualization of the cyst without extensive removal of the adjacent facet joint. SUMMARY OF BACKGROUND DATA/BACKGROUND:The use of tubular retractors for spinal surgery can potentially minimize tissue injury. Contralateral approaches may be beneficial in visualizing pathology that is located adjacent or under the facet joint. This approach has not been reported previously. METHODS:Sixteen consecutive patients were treated using this approach using tubular retractors and the operating microscope. A retrospective chart and imaging review was conducted to determine operative and clinical measures. Subsequently, patients were contacted to obtain long-term clinical follow-up. RESULTS:Nine patients had an excellent and 5 had a good outcome, with median follow-up of 18 months, 2 patients were lost due to lack of follow-up. The mean operative time was 105 minutes and in all cases the blood loss was <40 mL. No postoperative instability was noted. CONCLUSIONS:A contralateral approach using a tubular retractor system provides excellent visualization of the facet cyst allowing safe cyst resection and nerve root decompression without compromising the facet joint. Larger case series with longer follow-up are needed to assess stability.