Faculty Bibliography

BACKGROUND:The treatment of epidural spinal cord compression due to metastatic cancer represents an important clinical challenge. The NOMS (neurologic, oncologic, mechanical, and systemic) framework facilitates the determination of the optimal combination of systemic, radiation, and surgical therapies for individual patients. Spinal stereotactic radiosurgery (SRS) is an effective and safe modality for achieving durable control of local disease. Integrating SRS into the postoperative treatment plan allows surgical goals to be modified, thus decreasing the extent of tumor resection required. METHODS:Separation surgery is indicated for patients with spinal cord compression secondary to solid tumor metastases. During separation surgery, the spinal column is stabilized and the epidural tumor is resected without requiring significant vertebral body resection. RESULTS:Tumor separation from the spinal cord allows patients to undergo postoperative SRS. CONCLUSIONS:The combination of separation surgery and high-dose hypofractionated or single-fraction SRS results in high local tumor control at 1 year and is an effective palliative paradigm for this patient population.

BACKGROUND CONTEXT/BACKGROUND:Spine metastases occur frequently in patients with cancer. A variety of surgical approaches, including anterior transcavitary, lateral extracavitary, posterolateral, and/or combined techniques are used for spinal cord decompression and restoration of spinal stability. The incidence of symptomatic hardware failure is unknown for the majority of these approaches. PURPOSE/OBJECTIVE:The purpose of this study was to determine the incidence of symptomatic hardware failure and the associated risk factors in patients with metastatic epidural spinal cord compression (MESCC). STUDY DESIGN/SETTING/METHODS:This was a retrospective study. PATIENT SAMPLE/METHODS:The current series analyzes a cohort of 318 patients who underwent separation surgery, which involves single-stage posterolateral decompression and posterior segmental instrumentation for MESCC. OUTCOME MEASURES/METHODS:The event of interest was hardware failure; the competing event was death resulting from any cause. All patients were monitored for survival analysis. A competing risk analysis was conducted to examine univariately a number of potential risk factors associated with hardware failure, including junctional level, gender, construct length, and the presence or absence of prior chest wall resection. METHODS:A retrospective analysis and chart review were performed for 318 consecutive patients who underwent posterolateral decompression and posterior screw-rod fixation without supplemental anterior fixation from March 2004 to June 2011 at our institution. The median follow-up time for survivors without hardware failure was 399 days (range, 9-2,828), with a mean operative time of 3 hours. A total of 78% of patients died during the 7-year study period. RESULTS:Of the 318 patients, nine (2.8%) exhibited signs and symptoms of hardware failure and required revision of the instrumentation. Patients with chest wall resection and those with initial construct length greater than six contiguous spinal levels exhibited a statistically significantly higher risk of symptomatic hardware failure than their counterparts. We observed a trend toward an increased risk of failure in women compared with men (p=.09). CONCLUSIONS:The incidence of hardware failure is low in patients with MESCC who undergo posterolateral decompression and posterior screw-rod instrumentation. Moreover, the short operative time and low morbidity profile associated with this approach make it a reliable and acceptable method for the surgical treatment of MESCC. Patients with constructs spanning six or more levels or those with prior chest wall resection are at higher risk for instrumentation failure.

Significant evidence emerging in the spinal oncology literature recommends radiosurgery as a primary modality of treatment of spinal metastasis. Improvements in the methods of delivering radiation have increased the ability to provide a higher and more exacting dose of radiation to a tumor bed than previously. Using treatment-planning software, radiation is contoured around a specific lesion with the intent of administering a tumoricidal dose. Combined with a minimally invasive, tumor-load reducing surgery, this advanced form of radiation therapy can provide better local control of the tumor compared with conventional external beam radiation.

Treatment options for metastatic and primary spinal tumors have expanded in recent years, in part due to the advances made in stereotactic radiosurgery. For metastatic spinal tumors, our institution utilizes the neurologic, oncologic, mechanical, and systemic (NOMS) decision framework, which provides a treatment paradigm based on the neurologic, oncologic, mechanical and systemic status of the patient. Radiosurgery as a supplement to surgical decompression has allowed for less-invasive surgical procedures carrying minimal morbidity while still providing effective local tumor control. Although wide en bloc excision has traditionally been the goal for the treatment of high-grade primary spine tumors, recent studies have shown promise for radiosurgery in providing control in tumors such as chordomas and high-grade sarcomas. Despite advances in radiosurgery, there continues to be limitations in providing effective conformational doses with minimal toxicity to critical structures. One of the ways to circumvent this and supplement external beam radiation is through the use of brachytherapy delivered by radioactive plaque or seeds.

The NOMS considerations provide a dynamic decision framework to determine the optimal combination of systemic and radiation therapies and surgery. Generally, NSCLC metastases to the spine require SRS because cEBRT usually fails to provide consistent long-term local control. Patients with spinal cord compression secondary to NSCLC require surgical decompression to safely undergo SRS and to reduce the risk of radiation-induced spinal cord injury. Separation surgery allows spinal cord decompression and spinal stabilization using the posterior approach and, in combination with SRS, has been shown to provide reliable local control with low risk of wound complication or spinal hardware fracture.

OBJECT/OBJECTIVE:Radiation therapy is known to impair wound healing. Higher dose per fraction is believed to increase this risk. This study sought to quantify rates of wound complication in patients receiving preoperative conventionally fractionated radiotherapy (XRT) or high-dose hypofractionated image-guided radiation therapy (IGRT) for spinal metastasis, and to identify predictors of wound complication. METHODS:The records of 165 consecutive patients who underwent spine surgery for metastasis at Memorial Sloan-Kettering Cancer Center between 1999 and 2010, with a history of prior radiation therapy, were reviewed. Patients with primary spine tumors, 2 courses of prior radiation therapy to the surgical site, total dose < 9 Gy, or radiation therapy adjacent to or partially overlapping the surgical site, were excluded. One hundred thirty patients received XRT (≤ 3 Gy/fraction) and 35 received IGRT (> 3 Gy/fraction). The total dose prescribed to the 100% isodose line to treat the planning target volume was 18-30 Gy in 1-5 fractions. Clinical factors evaluated included age, Karnofsky Performance Scale score, body mass index, presence of diabetes, smoking, ambulatory status, prior surgery at same spinal site, preoperative laboratory results (hemoglobin, lymphocyte count, and albumin), perioperative chemotherapy or steroids, estimated blood loss, extent of stabilization hardware, time between radiation therapy and surgery, number of vertebral bodies irradiated, total radiation dose, and dose per fraction of radiation therapy. Wound complication was defined as poor healing, dehiscence, or infection. Potential predictors of wound complication were assessed by univariate analyses using competing-risk methods to adjust for risk of death. results: For XRT patients, median dose was 30 Gy (range 11.5-70 Gy) with 72% of them receiving 3 Gy × 10 fractions. For IGRT patients, 66% received 18-24 Gy × 1 fraction and 23% received 6 Gy × 5 fractions. Groups differed only by the mean number of vertebral bodies treated (4.6 XRT and 1.8 IGRT, p < 0.0001). Wound complications occurred at a median of 0.95 months (range 0.4-3.9 months). A total of 22 wound events occurred in the XRT group and 2 in the IGRT group. The 6-month cumulative incidence of wound complications for XRT was 17% and for IGRT was 6%. There was no significant difference in wound complications between groups (IGRT vs XRT: hazard ratio 0.31, 95% CI 0.08-1.3; p = 0.11). Higher dose per fraction appeared to be associated with a lower risk of wound complication (hazard ratio 0.27, 95% CI 0.06-1.15; p = 0.08), which trended toward significance. Univariate analyses did not reveal any significant predictors of wound complications. CONCLUSIONS:Patients who underwent XRT or IGRT did not have significantly different rates of postoperative wound complications. This finding may be explained by the treatment of fewer vertebral bodies in IGRT patients, or by the low overall number of total events. With a wound complication rate of 6%, preoperative IGRT, a highly conformal treatment, resulted in a very low rate of surgical wound complication.

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.