Faculty Bibliography

We present the case of a 65-year-old male with tumor-induced osteomalacia (TIO) caused by an FGF23-secreting phosphaturic tumor of C2 treated definitively with stereotactic body radiation therapy (SBRT) and kyphoplasty. The patient exhibited notable reduction in FGF23 6 weeks following radiotherapy. He also received a dose of the FGF23 monoclonal antibody, burosumab. We discuss the case with emphasis on radiation in the management of TIO. This case demonstrates SBRT as a well-tolerated local treatment option for the management of unresectable FGF23-producing tumors.

STUDY DESIGN/METHODS:General population utility valuation study. OBJECTIVE:The aim of this study was to develop a technique for calculating utilities from the Spine Oncology Study Group Outcomes Questionnaire v2.0 (SOSGOQ2.0). SUMMARY OF BACKGROUND DATA/BACKGROUND:The ability to calculate quality-adjusted life-years (QALYs) for metastatic spine disease would enhance treatment decision-making and facilitate economic analysis. QALYs are calculated using utilities. METHODS:Using a hybrid concept-retention and factorial analysis shortening approach, we first shortened the SOSGOQ2.0 to eight items (SOSGOQ-8D). This was done to lessen the cognitive burden of the utility valuation exercise. A general population sample of 2730 adults was then asked to evaluate 12 choice sets based on SOSGOQ-8D health states in a Discrete Choice Experiment. A utility scoring rubric was then developed using a mixed multinomial-logit regression model. RESULTS:We were able to reduce the SOSGOQ2.0 to an SOSGOQ-8D with a mean error of 0.003 and mean absolute error of 3.078 compared to the full questionnaire. The regression model demonstrated good predictive performance and was used to develop a utility scoring rubric. Regression results revealed that participants did not regard all SOSGOQ-8D items as equally important. CONCLUSION/CONCLUSIONS:We provide a simple technique for converting the SOSGOQ2.0 to utilities. The ability to evaluate QALYs in metastatic spine disease will facilitate economic analysis and patient counseling. We also quantify the importance of individual SOSGOQ-8D items. Clinicians should heed these findings and offer treatments that maximize function in the most important items.Level of Evidence: 3.

Spinal metastases are an increasing societal health burden secondary to improvements in systemic therapy. Estimates indicate that 100,000 or more people have symptomatic spine metastases requiring management. While open surgery and external beam radiotherapy have been the pillars of treatment, there is growing interest in more minimally invasive technologies (eg separation surgery) and non-operative interventions (eg percutaneous cementoplasty, stereotactic radiosurgery). The great expansion of these alternatives to open surgery and the prevalence of adjuvant therapeutic options means that treatment decision making is now complex and reliant upon multidisciplinary collaboration. To help facilitate construction of care plans that meet patient goals and expectations, clinical decision aids and prognostic scores have been developed. These have been shown to have superior predictive value relative to more classic prediction models and may become an increasingly important aspect of the clinical practice of spinal oncology. Here we overview current therapeutic advances in the management of spine metastases and highlight emerging areas for research. Given the rapid advancements in surgical technologies and adjuvants, the field is likely to undergo further transformative changes in the coming decade.

STUDY DESIGN/UNASSIGNED:International multicenter prospective observational cohort study on patients undergoing radiation +/- surgical intervention for the treatment of symptomatic spinal metastases. OBJECTIVES/UNASSIGNED:To investigate the association between the total Spinal Instability Neoplastic Score (SINS), individual SINS components and PROs. METHODS/UNASSIGNED:Data regarding patient demographics, diagnostics, treatment, and PROs (SF-36, SOSGOQ, EQ-5D) was collected at baseline, 6 weeks, and 12 weeks post-treatment. The SINS was assessed using routine diagnostic imaging. The association between SINS, PRO at baseline and change in PROs was examined with the Spearmans rank test. RESULTS/UNASSIGNED:< 0.001) for all patients. The presence of mechanical pain demonstrated to be moderately associated with a positive change in PROs at 12 weeks post-treatment. CONCLUSION/UNASSIGNED:Spinal instability, as defined by the SINS, was significantly correlated with PROs at baseline and change in PROs post-treatment. Mechanical pain, as a single SINS component, showed the highest correlations with PROs.

OBJECTIVE:High-grade metastatic epidural spinal cord compression from radioresistant tumor histologies is often treated with separation surgery and adjuvant stereotactic body radiation therapy. Historically, long-segment fixation is performed during separation surgery with posterior transpedicular fixation of a minimum of 2 spinal levels superior and inferior to the decompression. Previous experience with minimal access surgery techniques and percutaneous stabilization have highlighted reduced morbidity as an advantage to the use of shorter fixation constructs. Cement augmentation of pedicle screws is an attractive option for enhanced stabilization while performing shorter fixation. Herein, the authors describe their initial experience of open separation surgery using short-segment cement-augmented pedicle screw fixation for spinal reconstruction. METHODS:The authors performed a retrospective chart review of patients undergoing open (i.e., nonpercutaneous, minimal access surgery) separation surgery for high-grade epidural spinal cord compression using cement-augmented pedicle screws at single levels adjacent to the decompression level(s). Patient demographics, treatment data, operative complications, and short-term radiographic outcomes were evaluated. RESULTS:Overall, 44 patients met inclusion criteria with radiographic follow-up at a mean of 8.5 months. Involved levels included 19 thoracic, 5 thoracolumbar, and 20 lumbar. Cement augmentation through fenestrated pedicle screws was performed in 30 patients, and a vertebroplasty-type approach was used in the remaining 14 patients to augment screw purchase. One (2%) patient required an operative revision for a hardware complication. Three (7%) nonoperative radiographic hardware complications occurred, including 1 pathologic fracture at the index level causing progressive kyphosis and 2 incidences of haloing around a single screw. There were 2 wound complications that were managed conservatively without operative intervention. No cement-related complications occurred. CONCLUSIONS:Open posterolateral decompression utilizing short-segment cement-augmented pedicle screws is a viable alternative to long-segment instrumentation for reconstruction following separation surgery for metastatic spine tumors. Studies with longer follow-up are needed to determine the rates of delayed complications and the durability of these outcomes.

BACKGROUND:Historically, symptomatic, benign intradural extramedullary (IDEM) spine tumors have been managed with surgical resection. However, minimal robust data regarding patient-reported outcomes (PROs) following treatment of symptomatic lesions exists. Moreover, there are increasing reports of radiosurgical management of these lesions without robust health-related quality of life data. OBJECTIVE:To prospectively analyze PROs among patients with benign IDEM spine tumors undergoing surgical resection to define the symptomatic efficacy of surgery. METHODS:Prospective, single-center observational cohort study of patients with benign IDEM spine tumors undergoing open surgical resection. Pre- and postoperative Brief Pain Index (BPI) and MD Anderson Symptom Inventory (MDASI) questionnaires were used to quantitatively assess their symptom control after surgical intervention. Matched pairs were analyzed with the Wilcoxon signed-rank test. RESULTS:A total of 57 patients met inclusion criteria with both pre- and postoperative PROs. There were 35 schwannomas, 18 meningiomas, 2 neurofibromas, 1 paraganglioma, and 1 mixed schwannoma/neurofibroma. Most patients were American Spinal Injury Association Impairment (ASIA) E (93%) with high-grade spinal cord compression (77%), and underwent either a 2 or 3 level laminectomy (84%). Surgical resection resulted in statistically significant improvement in all 3 composite BPI constructs of pain-severity, pain-interference, and overall patient pain experience (P < .0001). Surgical resection resulted in statistically significant improvements in all composite scores for the MDASI core symptom severity, spine tumor, and disease interference constructs (P < .01). Three patients (5%) had postoperative complications requiring surgical interventions (2 wound revisions and 1 ventriculo-peritoneal shunt). CONCLUSION:Surgical resection of IDEM spine tumors provides rapid, significant, and durable improvement in PROs.

BACKGROUND:Over the last 2 decades, advances in systemic therapy have increased the expected overall survival for patients with cancer. It is unclear whether the same survival benefit has been conferred to patients requiring surgery for metastatic spinal disease. OBJECTIVE:To examine trends in postoperative survival over a 20-yr period for patients surgically treated for spinal metastatic disease. METHODS:Data were obtained for 1515 patients who underwent surgery for metastatic epidural spinal cord compression or tumor-related mechanical instability. Postoperative overall survival was calculated for all included patients using Kaplan-Meier methodology from date of surgery until death or last follow-up for those who were censored. Trends were analyzed using Cox proportional hazards modeling. RESULTS:Patients with renal, breast, lung, and colon cancers experienced a statistically significant improvement in survival over time based on the year of surgery (40%-100% improvement over the study period), whereas the overall survival trend for the entire cohort did not reach statistical significance (P = .12, median survival 0.71 yr, 95% CI 0.63-0.78). Patients presenting with synchronous metastatic disease had better survival compared to those presenting with metachronous disease (median overall survival: 0.94 vs 0.63 yr, respectively; log-rank P-value = .00001). CONCLUSION/CONCLUSIONS:The postoperative survival among patients with spinal metastases has improved over the past 20 yr, particularly in patients with kidney, breast, lung, and colon tumors metastatic to the spine. The observed survival improvement emphasizes the need for long-term outcome consideration in treatment decisions for patients undergoing surgery for spinal metastatic tumors.

BACKGROUND:Resection of large nerve sheath tumors in the lumbar spine using minimally invasive approaches is challenging, as approaches to tumors in this region may require facetectomy or partial resection of adjacent ribs for access to the involved neuroforamen and instrumentation across the involved joint to prevent subsequent kyphotic deformity. OBJECTIVE:To describe a robot-assisted retroperitoneal approach for resection of a lumbar nerve sheath tumor, obviating the need for facetectomy and instrumentation. The operation is described, together with intraoperative images and an annotated video, in the context of a schwannoma arising from the right L1 root. METHODS:The operation was performed by a urologic surgeon and a neurosurgeon. The patient was placed in lateral position, and the da Vinci Xi robot was used for retroperitoneal access via 5 ports along the right flank. Ultrasound was used to localize the tumor within the psoas. The tumor capsule was defined and released. Encountered nerves were stimulated, allowing small sensory nerves to be identified and safely divided. The tumor was traced into the right L1-L2 neuroforamen and removed. RESULTS:Complete en bloc resection of the tumor was achieved, including the paraspinal and foraminal components, without any removal of bone and without violation of the dura. CONCLUSION/CONCLUSIONS:In selected patients, a robot-assisted retroperitoneal approach represents a minimally invasive alternative to traditional approaches for resection of lumbar nerve sheath tumors. This approach obviates the need for bone removal and instrumented spinal fusion. Interdisciplinary collaboration, as well as use of adjunctive technologies, including intraoperative ultrasound and neurophysiologic monitoring, is advised.

BACKGROUND:Effective management of metastatic disease requires multidisciplinary input and entails high risk of disease-related and treatment-related morbidity and mortality. The factors that influence clinician decision-making around spinal metastases are not well understood. We conducted a qualitative study that included a multidisciplinary cohort of physicians to evaluate the decision-making process for treatment of spinal metastases from the clinician's perspective. METHODS:We recruited operative and nonoperative clinicians, including orthopaedic spine surgeons, neurosurgeons, radiation oncologists, and physiatrists, from across North America to participate in either a focus group or a semistructured interview. All interviews were audiorecorded and transcribed verbatim. We then performed a thematic analysis using all of the available transcript data. Investigators sequentially coded transcripts and identified recurring themes that encompass overarching patterns in the data and directly bear on the guiding study question. This was followed by the development of a thematic map that visually portrays the themes, the subthemes, and their interrelatedness, as well as their influence on treatment decision-making. RESULTS:The thematic analysis revealed that numerous factors influence provider-based decision-making for patients with spinal metastases, including clinical elements of the disease process, treatment guidelines, patient preferences, and the dynamics of the multidisciplinary care team. The most prominent feature that resonated across all of the interviews was the importance of multidisciplinary care and the necessity of cohesion among a team of diverse health-care providers. Respondents emphasized aspects of care-team dynamics, including effective communication and intimate knowledge of team-member preferences, as necessary for the development of appropriate treatment strategies. Participants maintained that the primary role in decision-making should remain with the patient. CONCLUSIONS:Numerous factors influence provider-based decision-making for patients with spinal metastases, including multidisciplinary team dynamics, business pressure, and clinician experience. Participants maintained a focus on shared decision-making with patients, which contrasts with patient preferences to defer decisions to the physician, as described in prior work. CLINICAL RELEVANCE/CONCLUSIONS:The results of this thematic analysis document the numerous factors that influence provider-based decision-making for patients with spinal metastases. Our results indicate that provider decisions regarding treatment are influenced by a combination of clinical characteristics, perceptions of patient quality of life, and the patient's preferences for care.

OBJECTIVES/OBJECTIVE:Intrathecal drug delivery systems (IDDS) are an important method of pain control for patients with refractory oncologic pain. Local anesthetics such as bupivacaine have been infused either alone or with opioids. While effective, bupivacaine can cause adverse effects such as numbness, weakness, and urinary retention. This study looks to establish a safe and efficacious fixed bupivacaine dosing algorithm in intrathecal pumps for cancer patients. MATERIALS AND METHODS/METHODS:A bupivacaine dosing algorithm was developed using data from 120 previous patients who underwent IDDS placement at Memorial Sloan Kettering Cancer Center. The outcomes were then evaluated for 43 subsequent patients who were treated with bupivacaine IDDS according to our aforementioned algorithm. RESULTS:Our data show that in patients treated with our bupivacaine guideline, visual analog pain scale scores decreased by 59% and oral morphine equivalence decreased by 70% from the period between IDDS implantation until discharge from the MSKCC hospital. However, 16.3% of our patients had bupivacaine-related side effects. CONCLUSIONS:For oncological patients, our data and experience support the initiation of intrathecal bupivacaine at the following doses: 5 mg/day for catheter tips in the cervical spine, 8 mg/day for catheter tips at T1-4, and 10 mg/day for catheter tips at T5-8. Given the higher likelihood of adverse effects in catheters at T9-12 and the lumbar spine, we start at 8 mg/day with close follow-up of the patient. Initiating these doses allow our patients to safely reach adequate analgesia faster, with a shorter hospitalization and quicker return to anti-cancer therapy.