Faculty Bibliography

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.

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%).

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.

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.