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OBJECTIVE Cancer patients with spinal metastases may undergo surgery without clear assessments of prognosis, thereby impacting the optimal palliative strategy. Because the morbidity of surgery may adversely impact recovery and initiation of adjuvant therapies, evaluation of risk factors associated with mortality risk and complications is critical. Evaluation of body composition of cancer patients as a surrogate for frailty is an emerging area of study for improving preoperative risk stratification. METHODS To examine the associations of muscle characteristics and adiposity with postoperative complications, length of stay, and mortality in patients with spinal metastases, the authors designed an observational study of 484 cancer patients who received surgical treatment for spinal metastases between 2010 and 2019. Sarcopenia, muscle radiodensity, visceral adiposity, and subcutaneous adiposity were assessed on routinely available 3-month preoperative CT images by using a validated deep learning methodology. The authors used k-means clustering analysis to identify patients with similar body composition characteristics. Regression models were used to examine the associations of sarcopenia, frailty, and clusters with the outcomes of interest. RESULTS Of 484 patients enrolled, 303 had evaluable CT data on muscle and adiposity (mean age 62.00 ± 11.91 years; 57.8% male). The authors identified 2 clusters with significantly different body composition characteristics and mortality risks after spine metastases surgery. Patients in cluster 2 (high-risk cluster) had lower muscle mass index (mean ± SD 41.16 ± 7.99 vs 50.13 ± 10.45 cm2/m2), lower subcutaneous fat area (147.62 ± 57.80 vs 289.83 ± 109.31 cm2), lower visceral fat area (82.28 ± 48.96 vs 239.26 ± 98.40 cm2), higher muscle radiodensity (35.67 ± 9.94 vs 31.13 ± 9.07 Hounsfield units [HU]), and significantly higher risk of 1-year mortality (adjusted HR 1.45, 95% CI 1.05–2.01, p = 0.02) than individuals in cluster 1 (low-risk cluster). Decreased muscle mass, muscle radiodensity, and adiposity were not associated with a higher rate of complications after surgery. Prolonged length of stay (> 7 days) was associated with low muscle radiodensity (mean 30.87 vs 35.23 HU, 95% CI 1.98–6.73, p < 0.001). CONCLUSIONS Body composition analysis shows promise for better risk stratification of patients with spinal metastases under consideration for surgery. Those with lower muscle mass and subcutaneous and visceral adiposity are at greater risk for inferior outcomes.

OBJECTIVE Paraspinal ganglioneuromas are rare tumors that arise from neural crest tissue and can cause morbidity via compression of adjacent organs and neurovascular structures. The authors investigated a case series of these tumors treated at their institution to determine clinical outcomes following resection. METHODS A retrospective review of a prospectively collected cohort of consecutive, pathology-confirmed, surgically treated paraspinal ganglioneuromas from 2001 to 2019 was performed at a tertiary cancer center. RESULTS Fifteen cases of paraspinal ganglioneuroma were identified: 47% were female and the median age at the time of surgery was 30 years (range 10–67 years). Resected tumors included 9 thoracic, 1 lumbar, and 5 sacral, with an average maximum tumor dimension of 6.8 cm (range 1–13.5 cm). Two patients had treated neuroblastomas that matured into ganglioneuromas. One patient had a secretory tumor causing systemic symptoms. Surgical approaches were anterior (n = 11), posterior (n = 2), or combined (n = 2). Seven (47%) and 5 (33%) patients underwent gross-total resection (GTR) or subtotal resection with minimal residual tumor, respectively. The complication rate was 20%, with no permanent neurological deficits or deaths. No patient had evidence of tumor recurrence or progression after a median follow-up of 68 months. CONCLUSIONS Surgical approaches and extent of resection for paraspinal ganglioneuromas must be heavily weighed against the advantages of aggressive debulking and decompression given the complication risk of these procedures. GTR can be curative, but even patients without complete tumor removal can show evidence of excellent long-term local control and clinical outcomes.

OBJECTIVETo characterize the clinical outcomes when stereotactic body radiation therapy (SBRT) alone is used to treat high-grade epidural disease without prior surgical decompression, the authors conducted a retrospective cohort study of patients treated at the Memorial Sloan Kettering Cancer Center between 2014 and 2018. The authors report locoregional failure (LRF) for a cohort of 31 cases treated with hypofractionated SBRT alone for grade 2 epidural spinal cord compression (ESCC) with radioresistant primary cancer histology.METHODSHigh-grade epidural disease was defined as grade 2 ESCC, which is notable for radiographic deformation of the spinal cord by metastatic disease. Kaplan-Meier survival curves and cumulative incidence functions were generated to examine the survival and incidence experiences of the sample level with respect to overall survival, LRF, and subsequent requirement of vertebral same-level surgery (SLS) due to tumor progression or fracture. Associations with dosimetric analysis were also examined.RESULTSTwenty-nine patients undergoing 31 episodes of hypofractionated SBRT alone for grade 2 ESCC between 2014 and 2018 were identified. The 1-year and 2-year cumulative incidences of LRF were 10.4% (95% CI 0–21.9) and 22.0% (95% CI 5.5–38.4), respectively. The median survival was 9.81 months (95% CI 8.12–18.54). The 1-year cumulative incidence of SLS was 6.8% (95% CI 0–16.0) and the 2-year incidence of SLS was 14.5% (95% CI 0.6–28.4). All patients who progressed to requiring surgery had index lesions at the thoracic apex (T5–7).CONCLUSIONSIn carefully selected patients, treatment of grade 2 ESCC disease with hypofractionated SBRT alone offers a 1-year cumulative incidence of LRF similar to that in low-grade ESCC and postseparation surgery adjuvant hypofractionated SBRT. Use of SBRT alone has a favorable safety profile and a low cumulative incidence of progressive disease requiring open surgical intervention (14.5%).

Osteoblastomas are a rare, benign primary bone tumor accounting for 1% of all primary bone tumors, with 40% occurring within the spine. Gross-total resection (GTR) is curative, although depending on location, this can require destabilization of the spine and necessitate instrumented fixation. Through the use of minimally invasive, muscle-sparing approaches, these lesions can be resected while maintaining structural integrity of the spine. The authors present a case report and technical note of a single patient describing the use of a purely endoscopic technique to resect a right L5 superior articulating process osteoblastoma in a 45-year-old woman. The patient underwent an image-guided endoscopic resection of her superior articulating facet osteoblastoma. Intraoperative CT demonstrated GTR. On postoperative examination, she remained neurologically intact with resolution of her pain. At follow-up, she remained pain free. Resection of lumbar osteoblastoma through a fully endoscopic approach was a safe and effective technique in this patient. This technique allowed for GTR without compromising spinal structural integrity, thus eliminating the need for instrumented fixation.

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.

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.

OBJECTIVEThe Spinal Instability Neoplastic Score (SINS) correlates with preoperative disability and response to stabilization, with patients with higher scores experiencing greater relief after surgery. However, there is a paucity of data demonstrating the extent to which each component contributes to preoperative clinical status and response to stabilization surgery. The objectives of this study were 2-fold. First, to determine how SINS components correlate with pre- and postoperative patient-reported outcomes (PROs). Second, to determine whether patients with higher SINS (10–12) in the “indeterminate” group respond differently to surgery compared to patients with lower SINS (7–9).METHODSSINS and PROs were prospectively collected in 131 patients undergoing stabilization surgery for metastatic spinal disease. Association of SINS components and their individual scores with preoperative symptom burden and PRO symptom change after surgery was analyzed using the Spearman rank correlation coefficient (rho) and the Kruskal-Wallis test. SINS and association with preoperative PRO scores and mean differences in post- and preoperative PRO scores were compared for 2 SINS categories within the indeterminate group (7–9 vs 10–12) using the Wilcoxon 2-sample test and Wilcoxon signed-rank test.RESULTSThe presence of mechanical pain, followed by metastatic location, correlated most strongly with preoperative functional disability measures and lower disability PRO scores following surgical stabilization. Blastic rather than lytic bone lesions demonstrated stronger association with pain reduction following stabilization. Following surgery, patients with SINS 10–12 demonstrated markedly greater improvement in pain and disability PRO scores nearly across the board compared to patients with SINS 7–9.CONCLUSIONSThe presence of mechanical pain has the strongest correlation with preoperative disability and improvement in pain and disability PRO scores after surgery. Radiographic components of SINS also correlate with preoperative symptom severity and postoperative PRO, supporting their utilization in evaluation of spinal instability. Among patients with indeterminate SINS, patients with higher scores experience greater reduction in pain and disability PRO scores following surgical stabilization, suggesting that the indeterminate-SINS group includes distinct populations.

OBJECTIVEPrimary 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.METHODSA 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.RESULTSA 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).CONCLUSIONSWhile 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.

OBJECTIVE The objective of this study was to review clinical outcomes following resection of giant spinal schwannomas. METHODS The authors conducted a retrospective review of a case series of patients with giant spinal schwannomas at a tertiary cancer hospital. RESULTS Thirty-two patients with giant spinal schwannomas underwent surgery between September 1998 and May 2013. Tumor size ranged from 2.5 cm to 14.6 cm with a median size of 5.8 cm. There were 9 females (28.1%) and 23 males (71.9%), and the median age was 47 years (range 23–83 years). The median follow-up duration was 36.0 months (range 12.2–132.4 months). Three patients (9.4%) experienced recurrence and required further treatment. All recurrences developed following subtotal resection (STR) of cellular or melanotic schwannoma. There were 3 melanotic (9.4%) and 6 cellular (18.8%) schwannomas included in this study. Among these histological variants, a 33.3% recurrence rate was noted. In 1 case of melanotic schwannoma, malignant transformation occurred. No recurrence occurred following gross-total resection (GTR) or when a fibrous capsule remained due to its adherence to functional nerve roots. CONCLUSIONS Resection is the treatment of choice for symptomatic or growing giant schwannomas, frequently requiring anterior or combined approaches, with the goals of symptom relief and prevention of recurrence. In this series, tumors that underwent GTR, or where only capsule remained, did not recur. Only melanotic and cellular schwannomas that underwent STR recurred.

OBJECT Despite advances in therapies using radiation oncology and spinal oncological surgery, there is a subgroup of patients with spinal metastases who suffer from progressive or recurrent epidural disease and remain at risk for neurological compromise. In this paper the authors describe their initial experience with a novel therapeutic approach that consists of intraarterial (IA) infusion of chemotherapy to treat progressive spinal metastatic disease. METHODS The main inclusion criterion was the presence of progressive, metastatic epidural disease to the spine causing spinal canal compromise in patients who were not candidates for the standard treatments of radiation therapy and/or surgery. All tumor histological types were eligible for this trial. Using the transfemoral arterial approach and standard neurointerventional techniques, all patients were treated with IA infusion of melphalan in the arteries supplying the epidural tumor. The protocol allowed for up to 3 procedures repeated at 3- to 6-week intervals. Outcome measures included physiological measures: 1) periprocedural complications according to the National Cancer Institute’s Common Terminology Criteria for Adverse Events; and 2) MRI to assess for tumor response. RESULTS Nine patients with progressive spinal metastatic disease and cord compression were enrolled in a Phase I clinical trial of selective IA chemotherapy. All patients had metastatic disease from solid organs and were not candidates for further radiation therapy or surgery. A total of 19 spinal intraarterial chemotherapy (SIAC) procedures were performed, and the follow-up period ranged from 1 to 7 months (median 3 months). There was 1 serious adverse event (febrile neutropenia). Local tumor control was seen in 8 of 9 patients, whereas tumor progression at the treated level was seen in 1 patient. CONCLUSIONS These preliminary results support the hypothesis that SIAC is feasible and safe.

Stereotactic body radiotherapy (SBRT) for spinal metastases is an emerging therapeutic option aimed at delivering high biologically effective doses to metastases while sparing the adjacent normal tissues. This technique has emerged following advances in radiation delivery that include sophisticated radiation treatment planning software, body immobilization devices, and capabilities of detecting and correcting patient positional deviations with imageguided radiotherapy. There are limited clinical data specifically supporting the role of SBRT as a superior alternative to conventional radiation in the postoperative patient. The focus of this review was to examine the evidence pertaining to spine SBRT in the treatment of spinal metastases and to provide a comprehensive analysis of published patterns of failure, with emphasis on the postoperative patient.

Objective The evolution of imaging techniques, along with highly effective radiation options has changed the way metastatic epidural tumors are treated. While high-grade epidural spinal cord compression (ESCC) frequently serves as an indication for surgical decompression, no consensus exists in the literature about the precise definition of this term. The advancement of the treatment paradigms in patients with metastatic tumors for the spine requires a clear grading scheme of ESCC. The degree of ESCC often serves as a major determinant in the decision to operate or irradiate. The purpose of this study was to determine the reliability and validity of a 6-point, MR imaging–based grading system for ESCC. Methods To determine the reliability of the grading scale, a survey was distributed to 7 spine surgeons who participate in the Spine Oncology Study Group. The MR images of 25 cervical or thoracic spinal tumors were distributed consisting of 1 sagittal image and 3 axial images at the identical level including T1-weighted, T2-weighted, and Gd-enhanced T1-weighted images. The survey was administered 3 times at 2-week intervals. The inter- and intrarater reliability was assessed. Results The inter- and intrarater reliability ranged from good to excellent when surgeons were asked to rate the degree of spinal cord compression using T2-weighted axial images. The T2-weighted images were superior indicators of ESCC compared with T1-weighted images with and without Gd. Conclusions The ESCC scale provides a valid and reliable instrument that may be used to describe the degree of ESCC based on T2-weighted MR images. This scale accounts for recent advances in the treatment of spinal metastases and may be used to provide an ESCC classification scheme for multicenter clinical trial and outcome studies.

OBJECT Adjuvant radiation following epidural spinal cord decompression for tumor is a powerful tool used to achieve local disease control and preserve neurological function. To the authors' knowledge, only 1 published report addresses adjuvant stereotactic radiosurgery after this procedure, but that study used significantly lower doses than are currently prescribed. The authors review their experience using high-dose single-fraction radiosurgery as a postoperative adjuvant following surgical decompression and instrumentation to assess long-term local tumor control, morbidity, and survival. METHODS A retrospective chart review identified 21 patients treated with surgical decompression and instrumentation for high-grade, epidural, spinal cord compression from tumor, followed by single-fraction high-dose spinal radiosurgery (dose range 18-24 Gy, median 24 Gy). Spinal cord dose was limited to a cord maximal dose of 14 Gy. Tumor histologies, time between surgery and radiosurgery, time to local recurrence after radiosurgery as assessed by serial MR imaging, and time to death were determined. Competing risk analysis was used to evaluate these end points. RESULTS In this series, 20 tumors treated (95%) were considered highly radioresistant to conventional external beam radiation. The planning target volume received a high dose (24 Gy) in 16 patients (76.2%), and a low dose (18 or 21 Gy) in 5 patients (23.8%). During the study, 15 (72%) of 21 patients died, and in all cases death was due to systemic progression as opposed to local failure. The median overall survival after radiosurgery was 310 days (range 37 days to not reached). One patient (4.8%) underwent repeat surgery for local failure and 2 patients (9.5%) underwent spine surgery for other reasons. Local control was maintained after radiosurgery in 17 (81%) of 21 patients until death or most recent follow-up, with an estimated 1-year local failure risk of 9.5%. Of the failures, 3 of 4 were noted in patients receiving low-dose radiosurgery, equaling an overall failure rate of 60% (3 of 5 patients) and a 1-year local failure estimated risk of 20%. Those patients receiving adjuvant stereotactic radiosurgery with a high dose had a 93.8% overall local control rate (15 of 16 patients), with a 1-year estimated failure risk of 6.3%. Competing risk analysis showed this to be a significant difference between radiosurgical doses. One patient experienced a significant radiation-related complication; there were no wound-related issues after radiosurgery. CONCLUSIONS Spine radiosurgery after surgical decompression and instrumentation for tumor is a safe and effective technique that can achieve local tumor control until death in the vast majority of patients. In this series, those patients who received a higher radiosurgical dose had a significantly better local control rate.

Object In this retrospective analysis the authors describe the assessment and outcomes of 90 patients who underwent placement of posterior instrumentation at the cervicothoracic junction following the resection of a primary or metastatic tumor during a 10-year period. Methods All patients underwent a posterolateral laminectomy including uni- or bilateral facetectomy, and 44 patients additionally required vertebral body resection and reconstruction. In patients who underwent C-6 or C-7 decompression, the posterior instrumentation strategies changed from the use of lateral mass plate systems (LMPSs) to lateral mass screw/rod systems (LMSRSs). Similarly, for T1–3 tumor decompression, the strategy shifted from sublaminar hook/rod systems (SHRSs) to the use of pedicle screw systems (PSSs) in which the surgeon used either a 6.25-mm rod or dual-diameter rods with or without a connector. Results The overall surgical complication rate was 19% including fixation failure in 11 patients (12%), 6 of whom required reoperation. Fixation failure rates for cervical decompression decreased from 2 (29%) of 7 patients in the LMPS group to 0 (0%) of 8 in the LMSRS group (p = 0.2). The fixation failure rates for thoracic decompression were 7 (15%) of 48 patients in the SHRS group, and there was a decrease to 2 (7%) of 27 in the PSS group (p = 0.48). Neurological and functional outcomes including American Spinal Injury Association, Eastern Cooperative Oncology Group, and Medical Research Council muscle strength and pain scores remained stable or improved in 94, 96, 100, and 96% of patients, respectively. Conclusions Current posterior instrumentation strategies involving LMSRSs and PSSs provide excellent and safe stabilization of the cervicothoracic junction following resection of primary or metastatic tumors.

Object. Patients with metastatic spine tumors often have multicolumn involvement and high-grade epidural compression, requiring circumferential decompression and instrumentation. Secondary medical and oncological issues add morbidity to combined approaches. The authors present their experience in using the single-stage posterolateral transpedicular approach (PTA) to decompress the spine circumferentially and to place instrumentation. Methods. From September 1997 to February 2004, 140 patients with spine metastases underwent the PTA. Magnetic resonance imaging revealed high-grade spinal cord compression in 120 patients (86%) and lytic vertebral body destruction in all patients. Preoperatively 84 patients (60%) received radiotherapy directed to the involved level and 42 (30%) underwent tumor embolization. Following circumferential decompression, all patients underwent anterior reconstruction with polymethylmethacrylate and Steinmann pins, and posterior segmental fixation. The median operative time was 5.1 hours, the median blood loss was 1500 ml, and the median hospital stay was 9 days. Ninety-six percent of the patients experienced postoperative pain improvement and improvement in or stabilization of neurological status. In 51 nonambulatory patients with poor Eastern Cooperative Oncology Group grades, 75% regained the ability to walk. One month postoperatively 90% of patients achieved good-to-excellent performance scores. The overall median patient survival time was 7.7 months. Patients with colon and lung carcinomas had significantly shorter survival times. Major operative complications occurred in 20 patients (14.3%). Wound complications occurred in 16 patients (11.4%), but this was not correlated with preoperative radiation treatment. Conclusions. The PTA allows circumferential epidural tumor decompression and the placement of anterior and posterior spinal column instrumention. Immediate spinal stability is achieved without the use of brace therapy. This technique achieved a high success rate for pain palliation, neurological preservation, and functional improvement, while avoiding the morbidity associated with combined approaches.