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.

STUDY DESIGN/METHODS:A single case is presented of a spontaneously resolving epidural arteriovenous fistula caused by a stab wound. OBJECTIVE:To demonstrate a unique case of a spontaneously resolving epidural arteriovenous fistula caused by a stab wound, as well as to present a brief review of pathology. SUMMARY OF BACKGROUND DATA/BACKGROUND:Spinal epidural arteriovenous fistulas (SEAVF) are high-flow vascular malformations characterized by an arteriovenous shunt involving the internal vertebral venous plexus (IVVP). SEAVFs can present with intramedullary, subarachnoid or epidural hemorrhages, spinal cord or nerve root compression, and progressive myelopathy secondary to medullary venous hypertension. The type of venous drainage (intradural, extradural, or mixed) strongly influences the mode of presentation. Spontaneous resolution of a spinal vascular malformation is a well-documented yet rare phenomenon. METHODS:Angiographical and magnetic resonance images of the lesion were obtained pre- and post spontaneous resolution. A brief review of the topic is also presented. RESULTS:Our observation identifies stabbing as an unusual mechanism for the formation of a SEAVF, and offers an angiographically documented example of complete spontaneous resolution of this type of vascular malformation. SEAVFs of traumatic origin have been previously reported, but we believe that our observation represents the first documentation of such a lesion being caused by stabbing with subsequent spontaneous resolution. CONCLUSION/CONCLUSIONS:Spinal epidural arteriovenous fistulas (SEAVFs) are increasingly diagnosed vascular malformations with the potential to inflict serious neurological damage if not recognized and treated in time. Spontaneous resolution of a spinal vascular malformation is a well-documented yet rare phenomenon. Our observation identifies stabbing as an unusual mechanism for the formation of a SEAVF, and offers an example of complete spontaneous resolution of this type of vascular malformation.

OBJECT/OBJECTIVE:Decompression surgery followed by adjuvant radiotherapy is an effective therapy for preservation or recovery of neurological function and achieving durable local disease control in patients suffering from metastatic epidural spinal cord compression (ESCC). The authors examine the outcomes of postoperative image-guided intensity-modulated radiation therapy delivered as single-fraction or hypofractionated stereotactic radiosurgery (SRS) for achieving long-term local tumor control. METHODS:A retrospective chart review identified 186 patients with ESCC from spinal metastases who were treated with surgical decompression, instrumentation, and postoperative radiation delivered as either single-fraction SRS (24 Gy) in 40 patients (21.5%), high-dose hypofractionated SRS (24-30 Gy in 3 fractions) in 37 patients (19.9%), or low-dose hypofractionated SRS (18-36 Gy in 5 or 6 fractions) in 109 patients (58.6%). The relationships between postoperative adjuvant SRS dosing and fractionation, patient characteristics, tumor histology-specific radiosensitivity, grade of ESCC, extent of surgical decompression, response to preoperative radiotherapy, and local tumor control were evaluated by competing risks analysis. RESULTS:The total cumulative incidence of local progression was 16.4% 1 year after SRS. Multivariate Gray competing risks analysis revealed a significant improvement in local control with high-dose hypofractionated SRS (4.1% cumulative incidence of local progression at 1 year, HR 0.12, p = 0.04) as compared with low-dose hypofractionated SRS (22.6% local progression at 1 year, HR 1). Although univariate analysis demonstrated a trend toward greater risk of local progression for patients in whom preoperative conventional external beam radiation therapy failed (22.2% local progression at 1 year, HR 1.96, p = 0.07) compared with patients who did not receive any preoperative radiotherapy (11.2% local progression at 1 year, HR 1), this association was not confirmed with multivariate analysis. No other variable significantly correlated with progression-free survival, including radiation sensitivity of tumor histology, grade of ESCC, extent of surgical decompression, or patient sex. CONCLUSIONS:Postoperative adjuvant SRS following epidural spinal cord decompression and instrumentation is a safe and effective strategy for establishing durable local tumor control regardless of tumor histology-specific radiosensitivity. Patients who received high-dose hypofractionated SRS demonstrated 1-year local progression rates of less than 5% (95% CI 0%-12.2%), which were superior to the results of low-dose hypofractionated SRS. The local progression rate after single-fraction SRS was less than 10% (95% CI 0%-19.0%).

Combined anterior cranial base resection is the mainstay of therapy for skull base malignancies. Improvements in surgical techniques and reconstruction have led to a reduction in morbidity and overall better survival rates. Meticulous attention to dural and skull base reconstruction is essential for reducing the major complications, including cerebrospinal fluid leak and pneumocephalus. Complications can be devastating, but timely effective management can limit the severity.

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.

OBJECTIVE:The evolution of imaging techniques, along with highly effective radiation options has changed the way metastatic epidural tumors are treated. While high-grade epidural spinal cord compression (ESCC) frequently serves as an indication for surgical decompression, no consensus exists in the literature about the precise definition of this term. The advancement of the treatment paradigms in patients with metastatic tumors for the spine requires a clear grading scheme of ESCC. The degree of ESCC often serves as a major determinant in the decision to operate or irradiate. The purpose of this study was to determine the reliability and validity of a 6-point, MR imaging-based grading system for ESCC. METHODS:To determine the reliability of the grading scale, a survey was distributed to 7 spine surgeons who participate in the Spine Oncology Study Group. The MR images of 25 cervical or thoracic spinal tumors were distributed consisting of 1 sagittal image and 3 axial images at the identical level including T1-weighted, T2-weighted, and Gd-enhanced T1-weighted images. The survey was administered 3 times at 2-week intervals. The inter- and intrarater reliability was assessed. RESULTS:The inter- and intrarater reliability ranged from good to excellent when surgeons were asked to rate the degree of spinal cord compression using T2-weighted axial images. The T2-weighted images were superior indicators of ESCC compared with T1-weighted images with and without Gd. CONCLUSIONS:The ESCC scale provides a valid and reliable instrument that may be used to describe the degree of ESCC based on T2-weighted MR images. This scale accounts for recent advances in the treatment of spinal metastases and may be used to provide an ESCC classification scheme for multicenter clinical trial and outcome studies.