Faculty Bibliography

PURPOSE/OBJECTIVE:To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS. METHODS AND MATERIALS/METHODS:The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included disease progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis. RESULTS:Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥ 3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias/myositis. Thirteen treated levels (36.1%) in 12 patients demonstrated progressive vertebral body collapse or endplate fractures at a median of 25.7 months (range 11.6-76.0), of which 5 (14%) became symptomatic and subsequently required percutaneous cement augmentation or surgery. CONCLUSIONS:In the longest-term series to date, high-dose single-fraction spinal SRS retained an excellent safety profile among long-term survivors (>5 years).

The best clinical treatment for spinal metastases requires an integrated approach with input from an interdisciplinary cancer team. The principle goals of treatment are maintenance or improvement in neurologic function and ambulation, spinal stability, durable tumor control, and pain relief. The past decade has witnessed an explosion of new technologies that have impacted our ability to reach these goals, such as separation surgery and minimally invasive spinal procedures. The biggest advance, however, has been the evolution of stereotactic radiosurgery that has demonstrated durable tumor control both when delivered as definitive therapy and as a postoperative adjuvant even for tumors considered markedly resistant to conventional external beam radiation. In this paper, we perform an update on the management of spinal metastases demonstrating the integration of these new technologies into a decision framework NOMS that assesses four basic aspects of a patient's spine disease: Neurologic, Oncologic, Mechanical Instability and Systemic disease.

BACKGROUND CONTEXT/BACKGROUND:Pathologic vertebral compression fractures (VCFs) represent a major source of morbidity and diminished quality of life in the spinal oncology population. Procedures with low morbidity that effectively treat patients with pathologic fractures are especially important in the cancer population where life expectancy is limited. Vertebroplasty and kyphoplasty are often not effective for mechanically unstable pathologic fractures extending into the pedicle and facet joints. Combination of cement augmentation and percutaneous instrumented stabilization represents a minimally invasive treatment option that does not delay radiation and systemic therapy. PURPOSE/OBJECTIVE:The objective of the study was to evaluate the safety and efficacy of cement-augmented short-segment percutaneous posterolateral instrumentation for tumor-associated VCF with pedicle and joint involvement. METHODS:Forty-four consecutive patients underwent cement-augmented percutaneous spinal fixation for unstable tumors between 2011 and 2014. Retrospective analysis of prospectively collected data, including visual analog pain scale (VAS) response score and procedural complications, was performed. RESULTS:Patients with a median composite Spinal Instability Neoplastic Scale score of 10 (range=8-15) were treated with constructs spanning one to four disk spaces (median of two spaces, constituting 84% of all cases). The proportion of patients with severe pain decreased from 86% preoperatively to 0%; 65% of patients reported no referable instability pain postoperatively. There was one adjacent-level fracture responsive to kyphoplasty, and one case of asymptomatic screw pullout. Two patients subsequently required decompression in the setting of disease progression despite radiation; there was no perioperative morbidity. CONCLUSIONS:Percutaneous cement-augmented posterolateral spinal fixation is a safe and effective option for palliation of appropriately selected mechanically unstable VCF that extends into pedicle and/or joint.

BACKGROUND:Tumor-associated sacral insufficiency fractures (SIF) present a significant clinical challenge. As survival increases for many malignancies, sacral fractures associated with metastases, sacral or extended pelvic radiation, and paraneoplastic osteoporosis are increasingly common and yet remain difficult to treat in the setting of the potentially significant morbidity of open sacral surgery. OBJECTIVE:To describe our prospective experience with sacroplasty for tumor-associated lesions, including the largest series to date of radiation-induced SIF. METHODS:Twenty-five patients with symptomatic SIF underwent 31 percutaneous fluoroscopy-guided sacroplasties with a median 5.8 mL of polymethyl methacrylate or a ceramic-resin composite under fluoroscopic guidance and with concurrent biopsy acquisition. Eighteen patients had fractures related to previous sacral or pelvic radiation; 4 had viable lytic lesions; and 2 had oncology-related osteoporosis. Postoperative pain reduction, procedural morbidity, and functional outcomes were recorded. RESULTS:Twenty of 25 patients (80%) had reduction in their visual analog pain score at a median follow-up of 6.5 months; no patients worsened. The mean visual analog scale score decreased from 8.8 to 4.7 postprocedurally (P < .001), with significant reductions regardless of the underlying pathology (P < .001 to P < .05). Six of 13 patients with pretreatment ambulatory impairment required fewer ambulatory aids and 3 were newly ambulatory. Extravertebral cement migration was noted in 18 procedures; however, no instance was clinically relevant. Six repeat or contralateral procedures were performed. No morbidity was encountered. CONCLUSION/CONCLUSIONS:Sacroplasty is a safe and effective option for the palliation of sacral fractures in the oncologic population.

PURPOSE/OBJECTIVE:Sterilization of surgical margins for lesions involving the dura is complicated by the tolerance of the spinal cord and/or cauda equina, especially in the setting of prior radiation therapy (RT); use of intraoperative brachytherapy may allow local delivery of therapeutic dose without damaging sensitive structures. METHODS AND MATERIALS/METHODS:Patients with malignant lesions involving the dura received intraoperative brachytherapy with a (32)P plaque after maximal resection of the tumor. Local recurrence (LR) was analyzed using competing risks analysis; overall survival was analyzed using Kaplan-Meier statistics. RESULTS:Between September 2009 and April 2013, 68 patients with 69 lesions in the spine were treated with the (32)P plaque. Median followup was 10 months. Most patients (n=59, 85.5%) had previously been treated with at least one course of prior RT to the treated site. About 38 (55%) lesions received postoperative RT (median dose, 30 Gy; range, 18-30 Gy). The LR and overall survival at 12 months were 25.5% (95% confidence interval [CI]=15.5-37%) and 59.5% (95% CI=46-73%), respectively. For patients who received postoperative RT, LR at 12 months was 18.5% (95% CI=7.5-33%) compared with 34% (95% CI=18-51%) for those who were treated with the plaque alone (p=0.08 and 0.04 on univariate and multivariable analysis, respectively). There were no acute or long-term complications from treatment observed in this cohort. CONCLUSIONS:The (32)P intraoperative brachytherapy plaque is a useful adjunct to surgical intervention for primary recurrent and metastatic lesions of the spine involving the dura, and is not associated with additional toxicity.

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.

BACKGROUND CONTEXT/BACKGROUND:Lumbar metastases can result in spinal instability and mechanical radiculopathy, characterized by radicular pain produced by axial loading. This pain pattern represents a definitive symptom of neoplastic instability and may serve as a reliable indication for surgical stabilization. PURPOSE/OBJECTIVE:We examined the results of surgical decompression and fixation in the treatment of mechanical radiculopathy. STUDY DESIGN/SETTING/METHODS:A retrospective clinical study. PATIENT SAMPLE/METHODS:An internally maintained spine neurosurgery database was queried between February 2002 and April 2010. Patients were identified and deemed eligible for inclusion in this study based on the presence of all the following: metastatic tumor, lumbar surgery, and lumbar radiculopathy. OUTCOME MEASURES/METHODS:Visual analog scale (VAS) of pain and Eastern Cooperative Oncology Group (ECOG) status. METHODS:The Memorial Sloan-Kettering Cancer Center Department of Neurosurgery operative database was queried over an 8-year period to identify all patients with spinal metastases who underwent lumbar surgery. Only patients whose operative indication included mechanical radiculopathy were included. Pre- and postoperative pain was assessed with the VAS of pain, whereas pre- and postoperative performance status was evaluated using the ECOG. RESULTS:Fifty-five patients were included in the cohort. L2 and L3 were the most common levels involved, and most patients underwent multilevel posterior decompression and instrumented fusion. After surgery, 98% of patients reported pain relief. A significant difference between average pre- and postoperative pain scores was found (p<.01). Overall, 41.5% of patients experienced improvement in their ECOG score postoperatively. CONCLUSIONS:Mechanical radiculopathy in patients with spinal metastases represents a highly reliable surgical indication. Spinal decompression and fixation is an effective treatment for pain palliation in 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.