Faculty Bibliography

OBJECTIVE The aim of this study was to evaluate the safety and efficacy of kyphoplasty treatment prior to spine stereotactic radiosurgery (SRS) in patients with spine metastases. METHODS A retrospective review of charts, radiology reports, and images was performed for all patients who received SRS (single fraction; either standalone or post-kyphoplasty) at a large tertiary cancer center between January 2012 and July 2015. Patient and tumor variables were documented, as well as treatment planning data and dosimetry. To measure the photon scatter due to polymethyl methacrylate, megavolt photon beam attenuation was determined experimentally as it passed through a kyphoplasty cement phantom. Corrected electron density values were recalculated and compared with uncorrected values. RESULTS Of 192 treatment levels in 164 unique patients who underwent single-fraction SRS, 17 (8.8%) were treated with kyphoplasty prior to radiation delivery to the index level. The median time from kyphoplasty to SRS was 22 days. Four of 192 treatments (2%) demonstrated local tumor recurrence or progression at the time of analysis. Of the 4 local failures, 1 patient had kyphoplasty prior to SRS. This recurrence occurred 18 months after SRS in the setting of widespread systemic disease and spinal tumor progression. Dosimetric review demonstrated a lower than average treatment dose for this case compared with the rest of the cohort. There were no significant differences in dosimetry analysis between the group of patients who underwent kyphoplasty prior to SRS and the remaining patients in the cohort. A preliminary analysis of polymethyl methacrylate showed that dosimetric errors due to uncorrected electron density values were insignificant. CONCLUSIONS In cases without epidural spinal cord compression, stabilization with cement augmentation prior to SRS is safe and does not alter the efficacy of the radiation or preclude physicians from adhering to SRS planning and contouring guidelines.

BACKGROUND:Whether primary or metastatic, tumors of the craniovertebral junction (CVJ) are rare and challenging. OBJECTIVE:To examine the surgical indications, operative variables, and outcomes in patients with tumors of the CVJ undergoing occipitocervical (OC) stabilization. METHODS:A single-institution, retrospective case series was performed from a prospectively maintained spine database. Patients with primary or metastatic tumors of the CVJ who underwent OC stabilization were identified. Out of 46 patients who underwent OC fusion, 39 were for tumor. Paired t -tests and Wilcoxon rank-sum tests were performed to assess for postoperative changes. RESULTS:Ten patients (26%) harbored primary tumors, and the remaining 29 (74%) had metastatic disease. Of the metastatic patients, 14 had a neurological deficit, 10 had severe neck pain, and 5 were deemed mechanically unstable. Postoperative visual analog pain scores were significantly reduced at all 3 follow-up times ( P < .001, 95% confidence interval [CI; 3.2, 6.0]; P = .001, 95% CI [2.6, 7.7]; P = .020, 95% CI [0.6, 5.5]). The percentage of patients who were ambulatory and neurologically improved or intact remained stable postoperatively with no significant declines. There were 2 perioperative mortalities (5%), and 13 patients (33%) experienced a major complication. CONCLUSIONS:In patients with primary or metastatic tumor of the CVJ, OC stabilization using a cervical screw-rod system affixed to a midline-keel buttress plate, with or without posterior decompression, is a reliable method for CVJ stabilization in the oncologic setting. Improvement in pain and preservation of neurological function was seen.

OBJECTIVE The authors of this study aimed to identify the incidence of and risk factors for preoperative deep venous thrombosis (DVT) in patients undergoing surgical treatment for spinal metastases. METHODS Univariate analysis of patient age, sex, ethnicity, laboratory values, comorbidities, preoperative ambulatory status, histopathological classification, spinal level, and surgical details was performed. Factors significantly associated with DVT univariately were entered into a multivariate logistic regression model. RESULTS The authors identified 314 patients, of whom 232 (73.9%) were screened preoperatively for a DVT. Of those screened, 22 (9.48%) were diagnosed with a DVT. The screened patients were older (median 62 vs 55 years, p = 0.0008), but otherwise similar in baseline characteristics. Nonambulatory status, previous history of DVT, lower partial thromboplastin time, and lower hemoglobin level were statistically significant and independent factors associated with positive results of screening for a DVT. Results of screening were positive in only 6.4% of ambulatory patients in contrast to 24.4% of nonambulatory patients, yielding an odds ratio of 4.73 (95% CI 1.88-11.90). All of the patients who had positive screening results underwent preoperative placement of an inferior vena cava filter. CONCLUSIONS Patients requiring surgery for spinal metastases represent a population with unique risks for venous thromboembolism. This study showed a 9.48% incidence of DVT in patients screened preoperatively. The highest rates of preoperative DVT were identified in nonambulatory patients, who were found to have a 4-fold increase in the likelihood of harboring a DVT. Understanding the preoperative thrombotic status may provide an opportunity for early intervention and risk stratification in this critically ill population.

STUDY DESIGN/METHODS:Systematic review. OBJECTIVE:Surgical decompression and reconstruction of symptomatic spinal metastases has improved the quality of life in cancer patients. However, most data has been collected on cohorts of patients with mixed tumor histopathology. We systematically reviewed the literature for prognostic factors specific to the surgical treatment of prostate metastases to the spine. METHODS:A systemic review of the literature was conducted to answer the following questions: Question 1. Describe the survival and functional outcomes of surgery or vertebral augmentation for prostate metastases to the spine. Question 2. Determine whether overall tumor burden, Gleason score, preoperative functional markers, and hormonal naivety favor operative intervention. Question 3. Establish whether clinical outcomes vary with the evolution of operative techniques. RESULTS:A total of 16 studies met the preset inclusion criteria. All included studies were retrospective series with a level of evidence of IV. Included studies consistently showed a large effect of hormone-naivety on overall survival. Additionally, studies consistently demonstrated an improvement in motor function and the ability to maintain/regain ambulation following surgery resulting in moderate strength of recommendation. All other parameters were of insufficient or low strength. CONCLUSIONS:There is a dearth of literature regarding the surgical treatment of prostate metastases to the spine, which represents an opportunity for future research. Based on existing evidence, it appears that the surgical treatment of prostate metastases to the spine has consistently favorable results. While no consistent preoperative indicators favor nonoperative treatment, hormone-naivety and high Karnofsky performance scores have positive effects on survival and clinical outcomes.

Patients with cancer are frequently affected by spinal metastases. Treatment is palliative, with the principle goals of pain relief, preservation of neurologic function, and improvement in quality of life. In the past decade, we have witnessed a dramatic change in the treatment paradigms due to the development of improved surgical strategies and systemic and radiation therapy. The most important change to these paradigms has been the integration of spinal stereotactic radiosurgery (SSRS), allowing delivery of tumoricidal radiation doses with sparing of nearby organs at risk. High-dose SSRS provides durable tumor control when used either as definitive therapy or as a postoperative adjuvant therapy. Integration of SSRS has fundamentally changed the indications for and type of surgery performed for metastatic spine tumors. Although the role for surgical intervention is well established, a clear trend toward less-aggressive, often minimally invasive techniques has been observed. Targeted therapies are also rapidly changing the way cancer is being treated and have demonstrated improved survival for a number of malignancies. As these treatment decisions become more complex, a multidisciplinary approach including medical oncologists, radiation oncologists, surgeons, interventionalists, and pain specialists is required. In this article, the current evidence affecting the treatment of spinal metastases is integrated into a decision framework that considers four principal assessments of a patient's spine disease: NOMS (neurologic, oncologic, mechanical instability, and systemic disease).

AIM/OBJECTIVE:to identify preoperative factors associated with morbidity/mortality, hospital length of stay (LOS), 30-day readmission and operation rates following spinal stereotactic radiosurgery (SRS) for spinal tumors. METHODS:The American College of Surgeons National Quality Improvement Program was queried from 2012 to 2014 to identify patients undergoing SRS for spinal tumors. Logistic regression was performed to identify predictors. RESULTS:2714 patients were identified; 6.8% had major morbidity or mortality, 6.9% were readmitted within 30 days and 4.3% had a subsequent operation within 30 days. Age, BMI and American Society of Anesthesiologist (ASA) class were predictive of LOS. Major morbidity was predicted by age >80, BMI >35, high ASA, pretreatment functional dependence and baseline comorbidities. Predictors of operation within 30 days included preoperative steroid use, renal failure, BMI >35 and if the treatment was nonelective. DISCUSSION/CONCLUSIONS:4-7% of patients undergoing SRS for spinal tumors have morbidity following the procedure. Factors predictive of morbidity, LOS, and subsequent operation included age, BMI, baseline comorbidities and functional status. CONCLUSION/CONCLUSIONS:Identification of preoperative patient-specific factors that are predictive of post-treatment outcome will aid in patient selection and patient counseling leading to greater patient satisfaction and hospital efficiency.

Metastatic epidural spinal cord compression (MESCC) is an oncologic emergency requiring prompt treatment to maximize neurologic function, ambulatory function and local control. Traditionally, options for MESCC included external beam radiation therapy with or without surgery. Surgery has usually been reserved for the patient with optimal performance status, single level MESCC or mechanical instability. Advances in external beam radiation therapy such as the development of stereotactic body radiation therapy have allowed for the delivery of high-dose radiation, allowing for both long-term pain and local control. Surgical advances, such as separation surgery, minimal access spine surgery and percutaneous instrumentation, have decreased surgical morbidity. This review summarizes the latest advances and evidence in MESCC to enable modern management.

OBJECTIVE Primary osteosarcoma of the spine is a rare osseous neoplasm. While previously reported retrospective studies have demonstrated that overall patient survival is impacted mostly by en bloc resection and chemotherapy, the continued management of residual disease remains to be elucidated. This systematic review was designed to address the role of revision surgery and multimodal adjuvant therapy in cases in which en bloc excision is not initially achieved. METHODS A systematic literature search spanning the years 1966 to 2015 was performed on PubMed, Medline, EMBASE, and Web of Science to identify reports describing outcomes of patients who underwent biopsy alone, neurological decompression, or intralesional resection for osteosarcoma of the spine. Studies were reviewed qualitatively, and the clinical course of individual patients was aggregated for quantitative meta-analysis. RESULTS A total of 16 studies were identified for inclusion in the systematic review, of which 8 case reports were summarized qualitatively. These studies strongly support the role of chemotherapy for overall survival and moderately support adjuvant radiation therapy for local control. The meta-analysis revealed a statistically significant benefit in overall survival for performing revision tumor debulking (p = 0.01) and also for chemotherapy at relapse (p < 0.01). Adjuvant radiation therapy was associated with longer survival, although this did not reach statistical significance (p = 0.06). CONCLUSIONS While the initial therapeutic goal in the management of osteosarcoma of the spine is neoadjuvant chemotherapy followed by en bloc marginal resection, this objective is not always achievable given anatomical constraints and other limitations at the time of initial clinical presentation. This systematic review supports the continued aggressive use of revision surgery and multimodal adjuvant therapy when possible to improve outcomes in patients who initially undergo subtotal debulking of osteosarcoma. A limitation of this systematic review is that lesions amenable to subsequent resection or tumors inherently more sensitive to adjuvants would exaggerate a therapeutic effect of these interventions when studied in a retrospective fashion.