Faculty Bibliography

BACKGROUND:A critical knowledge gap exists regarding the impact of neurologic deficits on surgical outcomes and health-related quality of life (HRQOL) for patients surgically treated for metastatic epidural spinal cord compression (MESCC). METHODS:This prospective, multicenter and international study analyzed the impact of the neurologic status on functional status, HRQOL, and postoperative survival. The collected data included the patient demographics, overall survival, American Spinal Injury Association (ASIA) impairment scale, Spinal Instability Neoplastic Score, treatment details and complications and HRQOL measures, including version 2 of the 36-Item Short Form Health Survey (SF-36v2) and version 2.0 of the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ2.0). RESULTS:A total of 239 patients surgically treated for spinal metastases were included. Six weeks after treatment, 99 of the 108 patients with a preoperative ASIA grade of E remained stable, 8 deteriorated to ASIA D, and 1 deteriorated to ASIA A. Of 55 patients with ASIA D, 27 improved to ASIA E, 27 remained stable and 1 deteriorated to ASIA C. Of 11 patients with ASIA A to C, 2 improved to ASIA E, 4 improved to ASIA D, and 5 remained stable. At the 6- and 12-week follow-up, better ASIA scores were associated with better scores on multiple SF-36v2 and SOSGOQ items. Postoperatively, patients with ASIA grades of A to D were more likely to have urinary tract infections and wound complications. Patients with a baseline ASIA grade of E or D survived significantly longer. CONCLUSIONS:Patients with neurologic deficits due to MESCC have worse HRQOL and decreased overall survival. Nevertheless, surgery can result in stabilization or improvement of neurologic function which may translate into better HRQOL. Postoperative care and follow-up are challenging for patients with neurologic deficits because they experience more complications.

OBJECTIVE:The current treatment of chordomas is associated with significant morbidity, high rates of local recurrence, and the potential for metastases. Stereotactic radiosurgery (SRS) as a primary treatment could reduce the need for en bloc resection to achieve wide or marginal margins. Spinal SRS outcomes support the exploration of SRS's role in the durable control of these conventionally radioresistant tumors. The goal of the study was to evaluate outcomes of patients with primary chordomas treated with spinal SRS alone or in combination with surgery. METHODS:Clinical records were reviewed for outcomes of patients with primary chordomas of the mobile spine and sacrum who underwent single-fraction SRS between 2006 and 2017. Radiographic local recurrence-free survival (LRFS), overall survival (OS), symptom response, and toxicity were assessed in relation to the extent of surgery. RESULTS:In total, 35 patients with de novo chordomas of the mobile spine (n = 17) and sacrum (n = 18) received SRS and had a median post-SRS follow-up duration of 38.8 months (range 2.0-122.9 months). The median planning target volume dose was a 24-Gy single fraction (range 18-24 Gy). Overall, 12 patients (34%) underwent definitive SRS and 23 patients (66%) underwent surgery and either neoadjuvant or postoperative adjuvant SRS. Definitive SRS was selectively used to treat both sacral (n = 7) and mobile spine (n = 5) chordomas. Surgical strategies for the mobile spine were either intralesional, gross-total resection (n = 5) or separation surgery (n = 7) and for the sacrum en bloc sacrectomy (n = 11). The 3- and 5-year LRFS rates were 86.2% and 80.5%, respectively. Among 32 patients (91%) receiving 24-Gy radiation doses, the 3- and 5-year LRFS rates were 96.3% and 89.9%, respectively. The 3- and 5-year OS rates were 90.0% and 84.3%, respectively. The symptom response rate to treatment was 88% for pain and radiculopathy. The extent or type of surgery was not associated with LRFS, OS, or symptom response rates (p > 0.05), but en bloc resection was associated with higher surgical toxicity, as measured using the Common Terminology Criteria for Adverse Events (version 5.0) classification tool, than epidural decompression and curettage/intralesional resection (p = 0.03). The long-term rate of toxicity ≥ grade 2 was 31%, including 20% grade 3 tissue necrosis, recurrent laryngeal nerve palsy, myelopathy, fracture, and secondary malignancy. CONCLUSIONS:High-dose spinal SRS offers the chance for durable radiological control and effective symptom relief with acceptable toxicity in patients with primary chordomas as either a definitive or adjuvant therapy.

OBJECTIVE:Dedifferentiated chordomas (DC) are genetically and clinically distinct from conventional chordomas (CC), exhibiting frequent SMARCB1 alterations and a more aggressive clinical course. We compared treatment and outcomes of DC and CC patients in a retrospective cohort study from a single, large-volume cancer center. METHODS:Overall, 11 DC patients were identified from 1994 to 2017 along with a cohort of 68 historical control patients with CC treated during the same time frame. Clinical variables and outcomes were collected from the medical record and Wilcoxon rank sum or Fisher exact tests were used to make comparisons between the two groups. Kaplan-Meier survival analysis and log-rank tests were used to compare DC and CC overall survival. RESULTS:DC demonstrated a bimodal age distribution at presentation (36% age 0-24; 64% age > 50). DC patients more commonly presented with metastatic disease than CC patients (36% vs. 3% p = 0.000). DC patients had significantly shorter time to local treatment failure after radiation therapy (11.1 months vs. 34.1 months, p = 0.000). The rate of distant metastasis following treatment was significantly higher in DC compared to CC (57% vs. 5%, p = 0.000). The median overall survival after diagnosis for DC was 20 months (95% CI 0-48 months) compared to 155 months (95% CI 94-216 months) for CC (p = 0.007). CONCLUSION/CONCLUSIONS:DC patients exhibit significantly higher rates of both synchronous and metachronous metastases, as well as shorter overall survival rates compared to conventional chordoma. The relatively poor survival outcomes with conventional therapies indicate the need to study targeted therapies for the treatment of DC.

BACKGROUND:Cancer patients experience pathological fractures and the typical poor bone quality frequently complicates stabilization. Methods for overcoming screw failure include utilization of fenestrated screws that permit the injection of bone cement into the vertebral body to augment fixation. OBJECTIVE:To evaluate the safety and efficacy of cement augmentation via fenestrated screws. METHODS:A retrospective chart review of patients with neoplastic spinal instability who underwent percutaneous instrumented stabilization with cement augmentation using fenestrated pedicle screws. Patient demographic and treatment data and intraoperative and postoperative complications were evaluated by chart review and radiographic evaluation. Prospectively collected patient reported outcomes (PRO) were evaluated at short (2- <6 mo) and long term (6-12 mo). RESULTS:Cement augmentation was performed in 216 fenestrated pedicle screws in 53 patients. Three patients required reoperation. One patient had an asymptomatic screw fracture at 6 mo postoperatively that did not require intervention. No cases of lucency around the pedicle screws, rod fractures, or cement extravasation into the spinal canal were observed. Eight cases of asymptomatic, radiographically-detected venous extravasation were found. Systemic complications included a pulmonary cement embolism, a lower extremity deep vein thrombosis, and a postoperative mortality secondary to pulmonary failure from widespread metastatic pulmonary infiltration. Significant improvement in PRO measures was found in short- and long-term analysis. CONCLUSION:Cement augmentation of pedicle screws is an effective method to enhance the durability of spinal constructs in the cancer population. Risks include cement extravasation into draining blood vessels, but risk of clinically significant extravasation appears to be exceedingly low.

Background/UNASSIGNED:Vertebral body compression fracture (VCF) is a complication following spinal stereotactic radiosurgery (SRS). However, the incidence of VCF in vertebrae adjacent to the level of SRS is unknown. This study aimed to determine the incidence of adjacent level VCF (adjVCF) following spinal SRS. Methods/UNASSIGNED:A retrospective review of 239 lesions treated with single-fraction SRS from 2011-2014 was performed. Clinical and pathologic factors were collected including evaluation of VCFs in adjacent levels to SRS site. In patients with adjVCFs, dose-volume histograms for adjacent-level endplates were calculated. Cox regression analysis was performed to determine any association among clinical factors and adjVCF occurrence. Results/UNASSIGNED:Median follow-up was 14.7 months. Twenty-six adjVCFs occurred (10.8%). Of the adjVCFs, 19 had metastases following SRS, and seven did not (2.9% of total treatments). Median time to fracture post-SRS was 13.5 months. In adjVCFs, median of the mean dose to adjacent level fractured endplate was 23.3 Gy, and median of the mean dose of sixteen non-fractured endplates immediately adjacent to the SRS site was 19.1 Gy. Age, gender, and histology were not associated with adjVCF. Conclusions/UNASSIGNED:AdjVCF after spinal SRS occurs at a rate of 2.9%, when excluding metastatic sites of disease. Adjacent level endplates should be investigated as an organ at risk during SRS planning.

Study Design/UNASSIGNED:Literature review. Objective/UNASSIGNED:To provide an overview of the recent advances in spinal oncology, emphasizing the key role of the surgeon in the treatment of patients with spinal metastatic tumors. Methods/UNASSIGNED:Literature review. Results/UNASSIGNED:Therapeutic advances led to longer survival times among cancer patients, placing significant emphasis on durable local control, optimization of quality of life, and daily function for patients with spinal metastatic tumors. Recent integration of modern diagnostic tools, precision oncologic treatment, and widespread use of new technologies has transformed the treatment of spinal metastases. Currently, multidisciplinary spinal oncology teams include spinal surgeons, radiation and medical oncologists, pain and rehabilitation specialists, and interventional radiologists. Consistent use of common language facilitates communication, definition of treatment indications and outcomes, alongside comparative clinical research. The main parameters used to characterize patients with spinal metastases include functional status and health-related quality of life, the spinal instability neoplastic score, the epidural spinal cord compression scale, tumor histology, and genomic profile. Conclusions/UNASSIGNED:Stereotactic body radiotherapy revolutionized spinal oncology through delivery of durable local tumor control regardless of tumor histology. Currently, the major surgical indications include mechanical instability and high-grade spinal cord compression, when applicable, with surgery providing notable improvement in the quality of life and functional status for appropriately selected patients. Surgical trends include less invasive surgery with emphasis on durable local control and spinal stabilization.

OBJECTIVEAs patients with metastatic cancer live longer, an increased emphasis is placed on long-term therapeutic outcomes. The current study evaluates outcomes of long-term cancer survivors following surgery for spinal metastases.METHODSThe study population included patients surgically treated at a tertiary cancer center between January 2010 and December 2015 who survived at least 24 months postoperatively. A retrospective chart and imaging review was performed to collect data regarding patient demographics; tumor histology; type and extent of spinal intervention; radiation data, including treatment dose and field; long-term sequelae, including local tumor control; and reoperations, repeat irradiation, or postoperative kyphoplasty at a previously treated level.RESULTSEighty-eight patients were identified, of whom 44 were male, with a mean age of 61 years. The mean clinical follow-up for the cohort was 44.6 months (range 24.2-88.3 months). Open posterolateral decompression and stabilization was performed in 67 patients and percutaneous minimally invasive surgery in 21. In the total cohort, 84% received postoperative adjuvant radiation and 27% were operated on for progression following radiation. Posttreatment local tumor progression was identified in 10 patients (11%) at the index treatment level and 5 additional patients had a marginal failure; all of these patients were treated with repeat irradiation with 5 patients requiring a reoperation. In total, at least 1 additional surgical intervention was performed at the index level in 20 (23%) of the 88 patients: 11 for hardware failure, 5 for progression of disease, 3 for wound complications, and 1 for postoperative hematoma. Most reoperations (85%) were delayed at more than 3 months from the index surgery. Wound infections or dehiscence requiring additional surgical intervention occurred in 3 patients, all of which occurred more than a year postoperatively. Kyphoplasty at a previously operated level was performed in 3 cases due to progressive fractures.CONCLUSIONSDurable tumor control can be achieved in long-term cancer survivors surgically treated for symptomatic spinal metastases with limited complications. Complications observed after long-term follow-up include local tumor recurrence/progression, marginal tumor control failures, early or late hardware complications, late wound complications, and progressive spinal instability or deformity.

An improved understanding of tumor biology, the ability to target tumor drivers, and the ability to harness the immune system have dramatically improved the expected survival of patients diagnosed with cancer. However, many patients continue to develop spine metastases that require local treatment with radiotherapy and surgery. Fortunately, the evolution of radiation delivery and operative techniques permits durable tumor control with a decreased risk of treatment-related toxicity and a greater emphasis on restoration of quality of life and daily function. Stereotactic body radiotherapy allows delivery of ablative radiation doses to the majority of spine tumors, reducing the need for surgery. Among patients who still require surgery for decompression of the spinal cord or spinal column stabilization, minimal access approaches and targeted tumor excision and ablation techniques minimize the surgical risk and facilitate postoperative recovery. Growing interdisciplinary collaboration among scientists and clinicians will further elucidate the synergistic possibilities among systemic, radiation, and surgical interventions for patients with spinal tumors and will bring many closer to curative therapies.

BACKGROUND:Despite major advances in radiation and systemic treatments, surgery remains a critical step in the multidisciplinary treatment of metastatic spinal cord tumors. OBJECTIVE:To describe the indications, rationale, and technique of "hybrid therapy" (separation surgery and concomitant spine stereotactic radiosurgery [SRS]) along with practical nuances. METHODS:Separation surgery describes a posterolateral approach for circumferential epidural decompression and stabilization. The goal is to decompress the spinal cord, stabilize the spine, and create adequate separation between the neural elements and the tumor for SRS to achieve durable tumor control. RESULTS:A transpedicular route to achieve ventrolateral access and limited resection of the tumorous vertebral body is carried out. In the setting of high-grade cord compression, caution must be taken when performing the tumor decompression. "Separation" of the ventral epidural tumor component anteriorly creates space for concomitant SRS while a simple laminectomy would not adequately achieve this goal. Dissection of the posterior longitudinal ligament allows maximal ventral decompression. Gross total tumor resection is not crucial for durable tumor control using the "hybrid therapy" model. Thus, attempts at ventral tumor resection may unnecessarily increase operative morbidity. Cement augmentation of the construct or vertebral body may improve construct stability. CT myelogram is the preferred exam for postoperative SRS planning. Radiosurgical planning constitutes a multidisciplinary effort and guidelines for contouring in the postoperative setting have recently become available. CONCLUSION:Separation surgery is an effective, well-tolerated, and reproducible surgery. It provides safe margins for concomitant SRS. Combined, this "Hybrid Therapy" allows durable local control, maintenance of spinal stability, and palliation of symptoms, while minimizing operative morbidity.