Faculty Bibliography

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.

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.

Beginning with basic stereotactic operative methods in neurosurgery, intraoperative navigation and image guidance systems have since become the norm in that field. Following the introduction of image guidance into spinal surgery, there has been a dramatic increase in its utilization across disciplines and pathologies. Spine tumor surgery encompasses a wide range of complex surgical techniques and treatment strategies. Similarly to deformity correction and trauma surgery, spine navigation holds potential to improve outcomes and optimize surgical technique for spinal tumors. Recent data demonstrate the applicability of neuro-navigation in the field of spinal oncology, particularly for spinal stabilization, maximizing extent of resection and integration of minimally invasive therapies. The rapid introduction of new, less invasive, and ablative surgical techniques in spine oncology coupled with the rising incidence of spinal metastatic disease make it imperative for spine surgeons to be familiar with the indications for and limitations of imaging guidance. Herein, we provide a practical, current concepts narrative review on the use of spinal navigation in three areas of spinal oncology: (a) extent of tumor resection, (b) spinal column stabilization, and (c) focal ablation techniques.

BACKGROUND:Despite our inability to accurately predict survival in many cancer patients, a life expectancy of at least 3 mo is historically necessary to be considered for surgical treatment of spinal metastases. OBJECTIVE:To compare health-related quality of life (HRQOL) in patients surviving <3 mo after surgical treatment to patients surviving >3 mo to assess the validity of this inclusion criteria. METHODS:Patients who underwent surgery for spinal metastases between August 2013 and May 2017 were retrospectively identified from an international cohort study. HRQOL was evaluated using generic and disease-specific outcome tools at baseline and at 6 and 12 wk postsurgery. The primary outcome was the HRQOL at 6 wk post-treatment measured by the Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ). RESULTS:A total of 253 patients were included: 40 patients died within the first 3 mo after surgery and 213 patients survived more than 3 mo. Patients surviving <3 mo after surgery presented with lower baseline performance status. Adjusted analyses for baseline performance status did not reveal a significant difference in HRQOL between both groups at 6 wk post-treatment. No significant difference in patient satisfaction at 6 wk with regard to their treatment could be detected between both groups. CONCLUSION:When controlled for baseline performance status, quality of life 6 wk after surgery for spinal metastasis is independent of survival. To optimize improvement in HRQOL for this patient population, baseline performance status should take priority over expected survival in the surgical decision-making process.

OBJECTIVE:To 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. METHODS:High-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. RESULTS:Twenty-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). CONCLUSIONS:In 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%).

BACKGROUND CONTEXT/BACKGROUND:The SORG machine-learning algorithms were previously developed for preoperative prediction of overall survival in spinal metastatic disease. On sub-group analysis of a previous external validation, these algorithms were found to have diminished performance on patients treated after 2010. PURPOSE/OBJECTIVE:The purpose of this study was to assess the performance of these algorithms on a large contemporary cohort of consecutive spinal metastatic disease patients. STUDY DESIGN/SETTING/METHODS:Retrospective study performed at a tertiary care referral center. PATIENT SAMPLE/METHODS:Patients of 18 years and older treated with surgery for metastatic spinal disease between 2014 and 2016. OUTCOME MEASURES/METHODS:Ninety-day and one-year mortality. METHODS:Baseline patient and tumor characteristics of the validation cohort were compared to the development cohort using bivariate logistic regression. Performance of the SORG algorithms on external validation in the contemporary cohort was assessed with discrimination (c-statistic and receiver operating curve), calibration (calibration plot, intercept, and slope), overall performance (Brier score compared to the null-model Brier score), and decision curve analysis. RESULTS:Overall, 200 patients were included with 90-day and 1-year mortality rates of 55 (27.6%) and 124 (62.9%), respectively. The contemporary external validation cohort and the developmental cohort differed significantly on primary tumor histology, presence of visceral metastases, American Spinal Injury Association impairment scale, and preoperative laboratory values. The SORG algorithms for 90-day and 1-year mortality retained good discriminative ability (c-statistic of 0.81 [95% confidence interval [CI], 0.74-0.87] and 0.84 [95% CI, 0.77-0.89]), overall performance, and decision curve analysis. The algorithm for 90-day mortality showed almost perfect calibration reflected in an overall calibration intercept of -0.07 (95% CI: -0.50, 0.35). The 1-year mortality algorithm underestimated mortality mainly for the lowest predicted probabilities with an overall intercept of 0.57 (95% CI: 0.18, 0.96). CONCLUSIONS:The SORG algorithms for survival in spinal metastatic disease generalized well to a contemporary cohort of consecutively treated patients from an external institutional. Further validation in international cohorts and large, prospective multi-institutional trials is required to confirm or refute the findings presented here. The open-access algorithms are available here: https://sorg-apps.shinyapps.io/spinemetssurvival/.

BACKGROUND:As of May 4, 2020, the coronavirus disease 2019 (COVID-19) pandemic has affected >3.5 million people and touched every inhabited continent. Accordingly, it has stressed health systems worldwide, leading to the cancellation of elective surgical cases and discussions regarding health care resource rationing. It is expected that rationing of surgical resources will continue even after the pandemic peak and may recur with future pandemics, creating a need for a means of triaging patients for emergent and elective spine surgery. METHODS:Using a modified Delphi technique, a cohort of 16 fellowship-trained spine surgeons from 10 academic medical centers constructed a scoring system for the triage and prioritization of emergent and elective spine surgeries. Three separate rounds of videoconferencing and written correspondence were used to reach a final scoring system. Sixteen test cases were used to optimize the scoring system so that it could categorize cases as requiring emergent, urgent, high-priority elective, or low-priority elective scheduling. RESULTS:The devised scoring system included 8 independent components: neurologic status, underlying spine stability, presentation of a high-risk postoperative complication, patient medical comorbidities, expected hospital course, expected discharge disposition, facility resource limitations, and local disease burden. The resultant calculator was deployed as a freely available Web-based calculator (https://jhuspine3.shinyapps.io/SpineUrgencyCalculator/). CONCLUSIONS:We present the first quantitative urgency scoring system for the triage and prioritizing of spine surgery cases in resource-limited settings. We believe that our scoring system, although not all encompassing, has potential value as a guide for triaging spine surgical cases during the COVID pandemic and post-COVID period.

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.