Faculty Bibliography

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.

BACKGROUND:The treatment of oligometastatic (≤5 metastases) spinal disease has trended toward ablative therapies, yet to the authors' knowledge little is known regarding the prognosis of patients presenting with oligometastatic spinal disease and the value of this approach. The objective of the current study was to compare the survival and clinical outcomes of patients with cancer with oligometastatic spinal disease with those of patients with polymetastatic (>5 metastases) disease. METHODS:The current study was an international, multicenter, prospective study. Patients who were admitted to a participating spine center with a diagnosis of spinal metastases and who underwent surgical intervention and/or radiotherapy between August 2013 and May 2017 were included. Data collected included demographics, overall survival, local control, and treatment information including surgical, radiotherapy, and systemic therapy details. Health-related quality of life (HRQOL) measures included the EuroQOL 5 dimensions 3-level questionnaire (EQ-5D-3L), the 36-Item Short Form Health Survey (SF-36v2), and the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ). RESULTS:Of the 393 patients included in the current study, 215 presented with oligometastatic disease and 178 presented with polymetastatic disease. A significant survival advantage of 90.1% versus 77.3% at 3 months and 77.0% versus 65.1% at 6 months from the time of treatment was found for patients presenting with oligometastatic disease compared with those with polymetastatic disease. It is important to note that both groups experienced significant improvements in multiple HRQOL measures at 6 months after treatment, with no differences in these outcome measures noted between the 2 groups. CONCLUSIONS:The treatment of oligometastatic disease appears to offer a significant survival advantage compared with polymetastatic disease, regardless of treatment choice. HRQOL measures were found to improve in both groups, demonstrating a palliative benefit for all treated patients.

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BACKGROUND:Minimal access surgery (MAS) allows for an early return to systemic and radiation therapy in patients with cancer, leading to its increasing usage in the treatment of spinal metastases. Systematic examination of surgical indications resulted in the development of an algorithm for implementation of MAS in the treatment of spinal metastases. The objective of the present study was to evaluate a spine tumor MAS treatment algorithm using patient-reported outcomes for patients with cancer undergoing treatment of spinal metastases. METHODS:We performed a prospective cohort study of patients who had undergone spinal percutaneous instrumented stabilization with the addition of MAS spinal cord or nerve root decompression and/or kyphoplasty when indicated at a tertiary cancer center from December 2013 to August 2016. Validated patient-reported outcome measures, including the Brief Pain Inventory and the MD Anderson Symptom Inventory-spine module, were used. The patient-reported outcome measures were collected and compared at baseline, 3 months, and long-term follow-up (range, 4.5-12 months). RESULTS:A total of 51 patients were included. MAS resulted in a statistically significant decrease in the severity of pain and improved activity, ability to work, and enjoyment of life (P < 0.001). The improvement was reported at the short- and long-term follow-up points. CONCLUSIONS:We present our treatment algorithm for MAS implementation in the treatment of thoracolumbar spinal metastases. Prospectively collected data have demonstrated that using this algorithm, MAS surgery for the treatment of spinal metastases results in significant decreases in pain severity and symptom interference with daily activities.

OBJECTIVEThe purpose of this study was to investigate the spectrum of current treatment protocols for managing newly diagnosed chordoma of the mobile spine and sacrum.METHODSA survey on the treatment of spinal chordoma was distributed electronically to members of the AOSpine Knowledge Forum Tumor, including neurosurgeons, orthopedic surgeons, and radiation oncologists from North America, South America, Europe, Asia, and Australia. Survey participants were pre-identified clinicians from centers with expertise in the treatment of spinal tumors. The suvey responses were analyzed using descriptive statistics.RESULTSThirty-nine of 43 (91%) participants completed the survey. Most (80%) indicated that they favor en bloc resection without preoperative neoadjuvant radiation therapy (RT) when en bloc resection is feasible with acceptable morbidity. The main area of disagreement was with the role of postoperative RT, where 41% preferred giving RT only if positive margins were achieved and 38% preferred giving RT irrespective of margin status. When en bloc resection would result in significant morbidity, 33% preferred planned intralesional resection followed by RT, and 33% preferred giving neoadjuvant RT prior to surgery. In total, 8 treatment protocols were identified: 3 in which en bloc resection is feasible with acceptable morbidity and 5 in which en bloc resection would result in significant morbidity.CONCLUSIONSThe results confirm that there is treatment variability across centers worldwide for managing newly diagnosed chordoma of the mobile spine and sacrum. This information will be used to design an international prospective cohort study to determine the most appropriate treatment strategy for patients with spinal chordoma.

OBJECTIVEPercutaneous vertebral augmentation procedures such as vertebroplasty and kyphoplasty are often performed in cancer patients to relieve mechanical axial-load pain due to pathological collapse deformities. The collapsed vertebrae in these patients can be associated with varying degrees of spinal canal compromise that can be worsened by kyphoplasty. In this study the authors evaluated changes to the spinal canal, in particular the cross-sectional area of the thecal sac, following balloon kyphoplasty (BKP) prior to stereotactic radiosurgery (SRS).METHODSThe authors retrospectively reviewed the records of all patients with symptomatic vertebral compression fractures caused by metastatic disease who underwent kyphoplasty prior to single-fraction SRS. The pre-BKP cross-sectional image, usually MRI, was compared to the post-BKP CT myelogram required for radiation treatment planning. The cross-sectional area of the thecal sac was calculated pre- and postkyphoplasty, and intraprocedural CT imaging was reviewed for epidural displacement of bone fragments, tumor, or polymethylmethacrylate (PMMA) extravasation. The postkyphoplasty imaging was also evaluated for evidence of fracture progression or fracture reduction.RESULTSAmong 30 consecutive patients, 41 vertebral levels were treated with kyphoplasty, and 24% (10/41) of the augmented levels showed a decreased cross-sectional area of the thecal sac. All 10 of these vertebral levels had preexisting epidural disease and destruction of the posterior vertebral body cortex. No bone fragments were displaced posteriorly. Minor epidural PMMA extravasation occurred in 20% (8/41) of the augmented levels but was present in only 1 of the 10 vertebral segments that showed a decreased cross-sectional area of the thecal sac postkyphoplasty.CONCLUSIONSIn patients with preexisting epidural disease and destruction of the posterior vertebral body cortex who are undergoing BKP for pathological fractures, there is an increased risk of further mass effect upon the thecal sac and the potential to alter the SRS treatment planning.

BACKGROUND:Conventional external beam radiation and stereotactic radiosurgery are common radiation techniques used to treat spinal tumors. Intraoperative brachytherapy (BT) may serve as an alternative when other options have been exhausted or as an adjunct in combination with other therapies. The objective of this study was to systematically review the literature on BT use in spinal tumor surgery. METHODS:PubMed and Embase databases were systematically queried for literature reporting the use of BT in the surgical treatment of spinal tumors. PRISMA guidelines were followed. A meta-analysis was performed. RESULTS:Of the 203 initial articles queried, 15 studies were included. Of the 370 total patients described, 78% were treated for spine metastases. Indications for BT included tumors refractory to previous treatments and inability to tolerate chemotherapy, radiation, and/or open surgery. Seed placement was the most common method of delivery (58%) compared with plaques (42%). BT was placed during an open procedure in 52%, and of the remaining percutaneous procedures, 47% were combined with cement augmentation. Tumor recurrence rates varied from 13% to 49%. Seven studies reporting visual analog scale scores reported significant improvement in pain control. CONCLUSIONS:BT was used to treat metastatic disease in patients who failed previous therapies and could not tolerate open surgery or further therapy. This review summarizes the major findings in the available literature pertaining to patient background, indications, and outcomes. Spinal BT seems to be a viable option for spine tumor treatment and should be made available at treating centers.