Minimally Invasive Techniques for Iliac Bolt Placement: 2-Dimensional Operative Video

As the popularity of minimally invasive surgery (MIS) continues to grow, novel techniques are needed to meet the demands of multisegment fixation for advanced spinal diseases. In one such example, iliac bolts are often required to anchor large fusion constructs, but MIS technical notes are missing from the literature.  A 67-yr-old female presented with a symptomatic coronal deformity: preoperative pelvic incidence = 47°, pelvic tilt = 19°, and lumbar lordosis = 29°, sagittal vertical axis = +5.4 cm with 30° of scoliosis. The operative plan included T10-ilium fusion with transforaminal interbody grafts at L2-3, L3-4, L4-5, and L5-S1. The intraoperative video is of minimally invasive placement of iliac bolts using the O-Arm Surgical Imaging System (Medtronic®). The patient consented to the procedure.  A mini-open exposure that remains above the fascial planes allows for multilevel instrumentation with appropriate decompression at the interbody segments. After the placement of the pedicle screws under image-guidance, the direction is turned to the minimally invasive iliac bolts. Following the trajectory described in the standard open approach,1 the posterior superior iliac spine (PSIS) is identified with the navigation probe, which will guide the Bovie cautery through the fascia. This opening assists in the trajectory of the navigated-awl tap toward the anterior superior iliac spine (ASIS). Next, 8.5 mm x 90 mm iliac screws were placed in the cannulated bone under navigation. After intraoperative image confirmation of screw placement, the contoured rods are threaded under the fascia. The setscrews lock the rod in position. MIS approaches obviate cross-linking the rods, rendering pelvic fixation more facile.  This technique allows for minimal dissection of the posterior pelvic soft tissue while maintaining adequate fixation.

Disparities in outcomes after spine surgery: a Michigan Spine Surgery Improvement Collaborative study

OBJECTIVE

Most studies on racial disparities in spine surgery lack data granularity to control for both comorbidities and self-assessment metrics. Analyses from large, multicenter surgical registries can provide an enhanced platform for understanding different factors that influence outcome. In this study, the authors aimed to determine the effects of race on outcomes after lumbar surgery, using patient-reported outcomes (PROs) in 3 areas: the North American Spine Society patient satisfaction index, the minimal clinically important difference (MCID) on the Oswestry Disability Index (ODI) for low-back pain, and return to work.

METHODS

The Michigan Spine Surgery Improvement Collaborative was queried for all elective lumbar operations. Patient race/ethnicity was categorized as Caucasian, African American, and "other." Measures of association between race and PROs were calculated with generalized estimating equations (GEEs) to report adjusted risk ratios.

RESULTS

The African American cohort consisted of a greater proportion of women with the highest comorbidity burden. Among the 7980 and 4222 patients followed up at 1 and 2 years postoperatively, respectively, African American patients experienced the lowest rates of satisfaction, MCID on ODI, and return to work. Following a GEE, African American race decreased the probability of satisfaction at both 1 and 2 years postoperatively. Race did not affect return to work or achieving MCID on the ODI. The variable of greatest association with all 3 PROs at both follow-up times was postoperative depression.

CONCLUSIONS

While a complex myriad of socioeconomic factors interplay between race and surgical success, the authors identified modifiable risk factors, specifically depression, that may improve PROs among African American patients after elective lumbar spine surgery.

The influence of sagittal spinopelvic alignment on patient discharge disposition following minimally invasive lumbar interbody fusion

Background

The aim of this study was to investigate the changes to spinopelvic sagittal alignment following minimally invasive (MIS) lumbar interbody fusion, and the influence of such changes on postoperative discharge disposition.

Methods

The Michigan Spine Surgery Improvement Collaborative was queried for all patients who underwent transforaminal lumbar interbody fusion (TLIF)or lateral lumbar interbody fusion (LLIF) procedures for degenerative spine disease. Several spinopelvic sagittal alignment parameters were measured, including sagittal vertical axis (SVA), lumbar lordosis, pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch. Primary outcome measure-discharge to a rehabilitation facility-was expressed as adjusted odds ratio (ORadj) following a multivariable logistical regression.

Results

Of the 83 patients in the study population, 11 (13.2%) were discharged to a rehabilitation facility. Preoperative SVA was equivalent. Postoperative SVA increased to 8.0 cm in the discharge-to-rehabilitation division versus a decrease to 3.6 cm in the discharge-to-home division (P<0.001). The odds of discharge to a rehabilitation facility increased by 25% for every 1-cm increase in postoperative sagittal balance (OR_adj =1.27, P=0.014). The strongest predictor of discharge to rehabilitation was increasing decade of life (OR_adj =3.13, P=0.201).

Conclusions

Correction of sagittal balance is associated with greater odds of discharge to home. These findings, coupled with the recognized implications of admission to a rehabilitation facility, will emphasize the importance of spine surgeons accounting for SVA into their surgical planning of MIS lumbar interbody fusions.

Sarcopenia as a Prognostic Factor for 90-Day and Overall Mortality in Patients Undergoing Spine Surgery for Metastatic Tumors: A Multicenter Retrospective Cohort Study

BACKGROUND

Novel methods in predicting survival in patients with spinal metastases may help guide clinical decision-making and stratify treatments regarding surgery vs palliative care.

OBJECTIVE

To evaluate whether the frailty/sarcopenia paradigm is predictive of survival and morbidity in patients undergoing surgery for spinal metastasis.

METHODS

A total of 271 patients from 4 tertiary care centers who had undergone surgery for spinal metastasis were identified. Frailty/sarcopenia was defined by psoas muscle size. Survival hazard ratios were calculated using multivariate analysis, with variables from demographic, functional, oncological, and surgical factors. Secondary outcomes included improvement of neurological function and postoperative morbidity.

RESULTS

Patients in the smallest psoas tertile had shorter overall survival compared to the middle and largest tertile. Psoas size (PS) predicted overall mortality more strongly than Tokuhashi score, Tomita score, and Karnofsky Performance Status (KPS). PS predicted 90-d mortality more strongly than Tokuhashi score, Tomita score, and KPS. Patients with a larger PS were more likely to have an improvement in deficit compared to the middle tertile. PS was not predictive of 30-d morbidity.

CONCLUSION

In patients undergoing surgery for spine metastases, PS as a surrogate for frailty/sarcopenia predicts 90-d and overall mortality, independent of demographic, functional, oncological, and surgical characteristics. The frailty/sarcopenia paradigm is a stronger predictor of survival at these time points than other standards. PS can be used in clinical decision-making to select which patients with metastatic spine tumors are appropriate surgical candidates.

The Effect of Antithrombotics on Hematoma Expansion in Small- to Moderate-Sized Traumatic Intraparenchymal Hemorrhages

BACKGROUND

Although pre-injury antithrombotic agents, including antiplatelets and anticoagulants, are historically associated with expansion of traumatic intraparenchymal hemorrhage (tIPH), the literature has poorly elucidated the actual risk of hematoma expansion on repeat computed tomography (CT). The objective was to determine the effect of antithrombotic agents on hematoma expansion in tIPH by comparing patients with and without pre-injury antithrombotic medication.

METHODS

The volume of all tIPHs over a 5-year period at an academic Level 1 trauma center was measured retrospectively. The initial tIPH was divided into 3 equally sized quantiles. The third tercile, representing the largest subset of tIPH, was then removed from the study population because these patients reflect a different pathophysiologic mechanism that may require a more acute and aggressive level of care with reversal agents and/or operative management. Per institutional policy, all patients with small- to moderate-sized hemorrhages received a 24-hour stability CT scan. Patients who received reversal agents were excluded.

RESULTS

Of the 105 patients with a tIPH on the initial head CT scan, small- to moderate-sized hemorrhages were <5 cm³. The size of tIPH on initial imaging did not statistically significantly differ between the antithrombotic cohort (0.7 ± 0.1 cm³) and the non-antithrombotic cohort (0.5 ± 0.1 cm³) (P = 0.091). Similarly, the volume of tIPH failed to differ on 24-hour repeat imaging (1.0 ± 0.2 cm³ vs. 0.6 ± 0.1 cm³, respectively, P = 0.172). Following a multiple linear regression, only history of stroke, not antithrombotic medications, predicted increased tIPH on 24-hour repeat imaging.

CONCLUSIONS

In small- to moderate-sized tIPH, withholding antithrombotic agents without reversal may be sufficient.

Patient navigation in epilepsy care

The concept of patient navigation was first introduced in 1989 by the American Cancer Society and was first implemented in 1990 by Dr. Harold Freeman in Harlem, NY. The role of a patient navigator (PN) is to coordinate care between the care team, the patient, and their family while also providing social support. In the last 30 years, patient navigation in oncological care has expanded internationally and has been shown to significantly improve patient care experience, especially in the United States cancer care system. Like oncology care, patients who require epilepsy care face socioeconomic and healthcare system barriers and are at significant risk of morbidity and mortality if their care needs are not met. Although shortcomings in epilepsy care are longstanding, the COVID-19 pandemic has exacerbated these issues as both patients and providers have reported significant delays in care secondary to the pandemic. Prior to the pandemic, preliminary studies had shown the potential efficacy of patient navigation in improving epilepsy care. Considering the evidence that such programs are helpful for severely disadvantaged cancer patients and in enhancing epilepsy care, we believe that professional societies should support and encourage PN programs for coordinated and comprehensive care for patients with epilepsy.

What have we learned from C5 palsy - A short communication

A study group on C5 palsy retrospectively reviewed 1001 cervical operations at their institutions in order to understand the incidence, prognosticators, pathogenesis, and outcome of C5 palsy after cervical operations. Three studies are summarized. C5 palsy was higher after posterior versus anterior operations. C4-C5 foraminotomy and age were the strongest predictors of C5 palsy after posterior surgeries and anterior cervical decompression-fusion, respectively. Among patients undergoing C4-C5 posterior laminoforaminotomy with instrumented fusion, cord shift on postoperative imaging was thought to be implicated in the pathogenesis of C5 palsy. Among affected patients, 81.4% recovered. Median time to resolution of C5 palsy was between 6 months to 1 year.

Risk Factors Associated with Symptomatic Deep Vein Thrombosis Following Elective Spine Surgery: A Case-Control Study

BACKGROUND

Few studies provide insight into risk factors (RFs) associated with postoperative deep vein thrombosis (DVT) following elective spinal surgery. DVTs are detrimental in this population because of the risk of pulmonary embolization or surgical site hemorrhage with treatment.

OBJECTIVE

Elective spine surgery patients have a low incidence of DVT, thus a case-control study was selected to investigate RFs associated with postoperative, symptomatic DVT.

METHODS

Cases were matched to controls in a 1:2 ratio based on surgery type. Risk of having a prior DVT and choice of subcutaneous heparin dosing following surgery was analyzed in a multivariate regression model with other potentially confounding variables.

RESULTS

A total of 195 patients were included in this study. Independent of patient age, history of DVT was associated with postoperative symptomatic DVT (odds ratio [OR], 4.09; 95% confidence interval [CI], 1.22-13.78). Two versus 3 times daily postoperative heparin dosing (OR, 1.56; 95% CI, 0.32-7.56), surgery length (OR, 1.32; 95% CI, 0.98-1.79), and patient age (OR, 1.04; 95% CI, 1.0-1.08) were not statistically significant, independent RFs. Older age and longer length of surgery trended toward association with DVT without reaching significance. Length of stay was increased from 3-5 days (P < 0.001) in DVT patients compared with controls.

CONCLUSIONS

These results suggest that patients with a history of DVT undergoing elective spinal surgery are at higher risk of developing symptomatic DVT postoperatively resulting in significantly increased length of stay. Further studies on additional preoperative screening and medical optimization in elective spine surgery patients may help reduce the rate of symptomatic, postoperative DVT.

The Effect of Physical Therapy on Time to Discharge After Lumbar Interbody Fusion

BACKGROUND

With a lesser degree of tissue destruction, patients undergoing minimally-invasive spine surgery are primed to benefit from early mobilization, which can further enhance recovery and hasten rehabilitation. We aimed to determine the role of physical therapy on earlier discharge after minimally-invasive transforaminal lumbar interbody fusion (TLIF).

METHODS

Michigan Spine Surgery Improvement Collaborative (MSSIC) provided patients undergoing one- and two-level minimally-invasive TLIF for degenerative lumbar disease. The study population was divided into patients with a one-day length of stay (LOS 1), two days (LOS 2), and three or more days (LOS ≥ 3) to maintain three equal-time cohorts. On POD 0, physical therapy (or, in very rare circumstances, a spine-care-specialized nurse in patients arriving to the in-patient floors late after hours) must evaluate capacity to ambulate.

RESULTS

Of the 101 patients, the median day of first ambulation statistically significantly increased from the LOS 1 to LOS ≥ 3 cohort (P = 0.007). Mean distance ambulated decreased from 156.5 ± 123.1 feet in the LOS 1 group, 108.9 ± 83.9 feet in the LOS 2 group, to 69.2 ± 58.3 feet in the LOS ≥ 3 group (P = 0.002). Patient-reported outcomes did not differ among the three cohorts. Following a multivariable ordinal logistical regression controlling for disposition to rehab over home (OR_adj = 5.47, P = 0.045), the odds of longer LOS decreased by 39% for every 50-feet ambulated (P = 0.002).

CONCLUSIONS

Time to first ambulation independently increases the odds of earlier discharge, regardless of comorbidity burden and surgical determinants.

Prevalence of Alternative Diagnoses and Implications for Management in Idiopathic Normal Pressure Hydrocephalus Patients

BACKGROUND

Following Bayes theorem, ventriculomegaly and ataxia confer only a 30% chance of idiopathic Normal Pressure Hydrocephalus (NPH). When coupled with positive responses to best diagnostic testing (extended lumbar drainage), 70% of patients recommended for shunting will not actually have NPH. This is inadequate clinical care.

OBJECTIVE

To determine the proportion of alternative and treatable diagnoses in patients referred to a multidisciplinary NPH clinic.

METHODS

Patients without previously diagnosed NPH were queried from prospectively collected data. At least 1 neurosurgeon, cognitive neurologist, and neuropsychologist jointly formulated best treatment plans.

RESULTS

Of 328 total patients, 45% had an alternative diagnosis; 11% of all patients improved with treatment of an alternative diagnosis. Of 87 patients with treatable conditions, the highest frequency of pathologies included sleep disorders, and cervical stenosis, followed by Parkinson disease. Anti-cholinergic burden was a contributor for multiple patients. Of 142 patients undergoing lumbar puncture, 71% had positive responses and referred to surgery. Compared to NPH patients, mimickers were statistically significantly older with lower Montreal Cognitive Assessment (MoCA) score and worse gait parameters. Overall, 26% of the original patients underwent shunting. Pre-post testing revealed a statistically significant improved MoCA score and gait parameters in those patients who underwent surgery with follow-up.

CONCLUSION

Because the Multidisciplinary NPH Clinic selected only 26% for surgery (corroborating 30% in Bayes theorem), an overwhelming majority of patients with suspected NPH will harbor alternative diagnoses. Identification of contributing/confounding conditions will support the meticulous work-up necessary to appropriately manage patients without NPH while optimizing clinical responses to shunting in correctly diagnosed patients.

Occipital fixation techniques and complications

Occipitocervical fusions in the adult population are most commonly indicated for neoplastic tumors invading the craniocervical junction (CCJ), rheumatological deformities compromising the foramen magnum, and traumatic dislocations resulting in occiput-C1 instability. Appropriate preoperative imaging will not only assist in identifying the pathology but also determine a treatment regimen for the diseased junction. A treatment algorithm for craniocervical disease is proposed. Lesions must first be identified as irreducible versus reducible: restore extension and/or distraction of the craniovertebral junction without injuring the neural elements. Irreducible lesions require decompression only, while reducible lesions require an added fusion. Techniques in fusion are broadly divided into external immobilization versus internal fixation. The former entails halo rings and tongs for a prolonged duration. Fixation surgeries vary from wiring to screw fixation of the occiput-C1 segment. Details of the operation as well as potential complications are discussed.

Predictors of patient dissatisfaction at 1 and 2 years after lumbar surgery

OBJECTIVE

As compensation transitions from a fee-for-service to pay-for-performance healthcare model, providers must prioritize patient-centered experiences. Here, the authors' primary aim was to identify predictors of patient dissatisfaction at 1 and 2 years after lumbar surgery.

METHODS

The Michigan Spine Surgery Improvement Collaborative (MSSIC) was queried for all lumbar operations at the 1- and 2-year follow-ups. Predictors of patients' postoperative contentment were identified per the North American Spine Surgery (NASS) Patient Satisfaction Index, wherein satisfied patients were assigned a score of 1 ("the treatment met my expectations") or 2 ("I did not improve as much as I had hoped, but I would undergo the same treatment for the same outcome") and unsatisfied patients were assigned a score of 3 ("I did not improve as much as I had hoped, and I would not undergo the same treatment for the same outcome") or 4 ("I am the same or worse than before treatment"). Multivariable Poisson generalized estimating equation models were used to report adjusted risk ratios (RRadj).

RESULTS

Among 5390 patients with a 1-year follow-up, 22% reported dissatisfaction postoperatively. Dissatisfaction was predicted by higher body mass index (RRadj =1.07, p < 0.001), African American race compared to white (RRadj = 1.51, p < 0.001), education level less than high school graduation compared to a high school diploma or equivalent (RRadj = 1.25, p = 0.008), smoking (RRadj = 1.34, p < 0.001), daily preoperative opioid use > 6 months (RRadj = 1.22, p < 0.001), depression (RRadj = 1.31, p < 0.001), symptom duration > 1 year (RRadj = 1.32, p < 0.001), previous spine surgery (RRadj = 1.32, p < 0.001), and higher baseline numeric rating scale (NRS)-back pain score (RRadj = 1.04, p = 0.002). Conversely, an education level higher than high school graduation, independent ambulation (RRadj = 0.90, p = 0.039), higher baseline NRS-leg pain score (RRadj = 0.97, p = 0.013), and fusion surgery (RRadj = 0.88, p = 0.014) decreased dissatisfaction.Among 2776 patients with a 2-year follow-up, 22% reported dissatisfaction postoperatively. Dissatisfaction was predicted by a non-white race, current smoking (RRadj = 1.26, p = 0.004), depression (RRadj = 1.34, p < 0.001), symptom duration > 1 year (RRadj = 1.47, p < 0.001), previous spine surgery (RRadj = 1.28, p < 0.001), and higher baseline NRS-back pain score (RRadj = 1.06, p = 0.003). Conversely, at least some college education (RRadj = 0.87, p = 0.035) decreased the risk of dissatisfaction.

CONCLUSIONS

Both comorbid conditions and socioeconomic circumstances must be considered in counseling patients on postoperative expectations. After race, symptom duration was the strongest predictor of dissatisfaction; thus, patient-centered measures must be prioritized. These findings should serve as a tool for surgeons to identify at-risk populations that may need more attention regarding effective communication and additional preoperative counseling to address potential barriers unique to their situation.

CMET-15. SARCOPENIA INDEPENDENTLY AND STRONGLY PREDICTS SURVIVAL IN PATIENTS UNDERGOING SPINE SURGERY FOR METASTATIC TUMORS

INTRODUCTION

Predicting survival and surgical morbidity in patients with spinal metastases would help guide clinical decision making and stratify treatments between surgical intervention and palliative care. This multi-center retrospective cohort study evaluates whether the frailty/sarcopenia paradigm, as measured by psoas size, is predictive of survival in patients undergoing surgery for spinal metastasis.

METHODS

271 patients from four institutes who had undergone surgery for spinal metastasis were identified. Morphometric measurements were taken of the psoas muscle at the L4 vertebral level < 200d from surgery. Mortality hazard ratios were calculated using multivariate analysis, with variables included from past medical history, type and extent of tumor spread, type and intensity of surgery, and postoperative chemotherapy or radiation.

RESULTS

Psoas size was predictive of overall mortality; patients in the smallest tertile had shorter overall survival compared to the middle (OR 0.52, p< 0.001) and largest tertile (OR 0.45, p< 0.001). Psoas size predicted overall mortality more strongly than Tokuhashi score (OR 0.91, p= 0.010), Tomita score (OR 1.07, p= 0.04), and KPS (OR 0.99, p= 0.58). Psoas size was also predictive of 90-day survival; patients in the smallest tertile had shorter 90-day survival compared to the middle (OR 0.24, p= 0.003) and largest tertile (OR 0.16, p= 0.001). Psoas size predicted 90-day mortality more strongly than Tokuhashi score (OR 0.73, p= 0.002), Tomita score (OR 1.00, p= 0.92), and KPS (OR 0.98, p= 0.39).

CONCLUSION

In patients undergoing surgery for spine metastases, psoas size as a surrogate for frailty/sarcopenia predicts 90-day and overall mortality, independent of demographical, functional, oncological, and surgical characteristics. The sarcopenia/frailty paradigm is a stronger predictor of survival at these time points than the Tokuhashi score, Tomita score, and KPS. Psoas size can be used in clinical decision-making to select which patients with metastatic spine tumors are appropriate surgical candidates.

INNV-21. IN NEWLY-DIAGNOSED GLIOBLASTOMA, FRAILTY/SARCOPENIA PREDICTS 30D MORBIDITY & 30D, 90D, AND OVERALL MORTALITY AS ACCURATELY AS CURRENT STANDARDS

INTRODUCTION

Identification of novel prognostic biomarkers for glioblastoma (GBM) could stratify patients between aggressive or palliative treatments. Frailty, as measured by sarcopenia (lack of muscle mass), has been proven to predict survival in cancers. We evaluate whether the frailty/sarcopenia phenotype (FSP) predicts morbidity and mortality in GBM, and compare it to other survival markers.

METHODS

In 257 patients undergoing initial diagnostic surgery for GBM, FSP was defined by temporalis muscle thickness from preoperative MRI; patients were grouped into tertiles (thirds) based on size, which corresponded to the severity of FSP. Morbidity and mortality hazard ratios were calculated from surgery using multivariate analysis, accounting for age, gender, past medical history, tumor focality / laterality / eloquence / volume, extent of resection, MGMT / IDH status, and initiation of postoperative chemo/radiation. Morbidity was defined as any of these events within 30d: DVT, PE, SSI, UTI, MI, urinary retention, ileus, readmission.

RESULTS

FSP at diagnostic surgery predicted any morbidity (OR2.98, P= 0.005) at 30d. FSP at diagnostic surgery was the only risk factor associated with 30d mortality (OR10.0, P= 0.030), and was also strongly associated with 90d mortality (OR25.0, P= 0.003). FSP at diagnostic surgery was associated with decreased overall survival (OR0.41, P< 0.001) at a level comparable to other mortality predictors, including temozolomide/EBRT (OR0.27), gross total resection (OR0.54), favorable MGMT (OR0.44) or IDH (OR0.44) mutations. Kaplan-Meier curves display overall survival based on severity of FSP.

CONCLUSION

FSP is a preoperative, simple, accurate, and non-invasive methodology to predict 30d morbidity & 30-day, 90-day, and overall mortality from diagnosis in GBM. FSP is independent of age (not an age surrogate), demographic, oncologic, genetic, surgical, and therapeutic factors. Mortality prediction is comparable to temozolamid/EBRT, total resection, MGMT, and IDH. It is a low cost, intuitive, and potentially universal methodology to guide treatment decision making.

A direct comparison of prophylactic low-molecular-weight heparin versus unfractionated heparin in neurosurgery: A meta-analysis

Background

Several studies have confirmed the role of prophylactic low-molecular-weight heparin (LMWH) for venous thromboembolism (VTE) in neurosurgery; however, a paucity of literature has assessed its safety and efficacy versus prophylactic unfractionated heparin (UFH). The objective is to present a meta-analysis directly comparing prophylactic LMWH to UFH for the prevention of VTE in neurosurgery.

Materials and Methods

Relevant studies that directly compared LMWH to UFH for prophylaxis of VTE in neurosurgery and/or spine surgery were identified by MEDLINE and EMBASE searches plus a scrutiny of references from the original articles and reviews. Three randomized trials were included in the meta-analysis. Efficacy and safety were ascertained per three primary outcome measures: VTE, minor complications (decline in hemoglobin/hematocrit), and major complications. Forest plot analysis provided odds ratio (OR), 95% confidence intervals (CIs), and P-values.

Results

Of the 429 patients in the pooled analysis, the postoperative VTE rate of 5.6% (12/213) after LMWH chemoprophylaxis was equivalent to 3.7% (8/216) after UFH chemoprophylaxis (OR = 1.42, 95% CI 0.62-3.75, P = 0.308). Minor complications of 4.7% versus 4.6%, respectively, were nearly equal (OR = 1.01, 95% CI 0.41- 2.50, P = 0.929). All four major complications included intracranial hemorrhages: three after LMWH (1.4%) and one after UFH (0.5%) (OR = 2.32, 95% CI 0.34-16.01, P = 0.831). Tests for heterogeneity were nonsignificant in all three outcome measures.

Conclusion

Rates of VTE, minor complications, and major complications were equivalent between prophylactic LMWH and UFH in neurosurgery. Further, randomized clinical trials comparing the two heparin products are required to elucidate superior safety and efficacy in neurosurgical patients.

Trends in the Abscopal Effect After Radiation to Spinal Metastases: A Systematic Review

While the abscopal effect has been previously described, the phenomenon has been poorly defined in the case of spinal metastases. This article is unique in that we present the first systematic review of the abscopal effect after radiation therapy to metastatic spinal cancer, especially since the spinal column represents one of the most common metastatic locations. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) resources, a systematic review identified relevant studies via a computer-aided search of MEDLINE and Embase. Ten publications that met the inclusion and exclusion criteria from the PRISMA flow diagram described a total of 13 patients, 76.9% of whom demonstrated image findings of the abscopal effect. In summary, important trends in the nine patients who experienced the abscopal effect in this review include higher doses of radiation and treatment with immunomodulators, both of which may help guide treatment paradigms for spinal metastases superimposed on diffuse metastatic disease. These trends, however, still warrant further investigations with experimental and clinical studies for a mechanistic understanding of the abscopal effect.