The effect of cannabinoids on single-level lumbar arthrodesis outcomes in a rat model.

BACKGROUND CONTEXT: The opioid epidemic is a public health crisis affecting spine care and pain management. Medical marijuana is a potential non-opioid analgesic yet to be studied in the surgical setting since its effects on bone healing are not fully understood. Studies have demonstrated analgesic and potentially osteoinductive properties of cannabinoids with endocannabinoid receptor expression in bone tissue. PURPOSE: We hypothesize that tetrahydrocannabinol (THC) and cannabidiol (CBD) will not decrease bone healing in spinal fusion. STUDY DESIGN: Seventy-eight adult Sprague-Dawley rats were used for this study. Utilizing allogenic bone grafts (6 donor rats), posterolateral inter-transverse lumbar fusion at the L4-L5 level was performed. The animals were equally divided into four treatment groups, each receiving 0.1 ml intraperitoneal injections weekly as follows: placebo (saline), 5 mg/kg THC, 5 mg/kg CBD, and a combination of 5 mg/kg THC and 5mg/kg CBD (Combo). METHODS: Callus tissue was harvested 2- and 8-weeks post-surgery for qPCR assessment to quantify changes in the expression of osteogenic genes. Manual palpation was done to assess the strength of the L4-L5 arthrodesis on all rats. µCT image-based callus analysis and histology were performed. One-way ANOVA followed by post hoc comparisons was performed. RESULTS: µCT demonstrated no significant differences. Treatment groups had slightly increased bone volume and density compared to control. qPCR at two weeks indicated downregulated RANKL/OPG ratios skewing towards osteogenesis in the CBD group, with the THC and CBD+THC groups demonstrating a downward trend (p>.05). ALPL, BMP4, and SOST were significantly higher in the CBD group, with CTNNB1 and RUNX2 also showing an upregulating trend. The CBD group showed elevation in Col1A1 and MMP13. Data at eight weeks showed ALPL, RUNX2, BMP4, and SOST were downregulated for all treatment groups. In the CBD+THC group, RANK, RANKL, and OPG were downregulated. OPG downregulation reached significance for the THC and CBD+THC group compared to saline. Interestingly, the RANKL/OPG ratio showed upregulation in the CBD and CBD+THC groups. RANKL showed upregulation in the CBD group. At 2 and 8 weeks, the CBD treatment group showed superior histological progression, increasing between time points. CONCLUSION: This study demonstrates that CBD and THC have no adverse effect on bone healing and the rate of spinal fusion in rats. Osteogenic factors were upregulated in the CBD-treated groups at two weeks, which indicates a potential for bone regeneration. In this group, compared to control, the RANKL/OPG ratio at the early healing phase demonstrates the inhibition of osteoclast differentiation, enhancing bone formation. Interestingly, it shows promoted osteoclast differentiation at the later healing phase, enhancing bone remodeling. This aligns with the physiological expectation of a lower ratio in the early phases and a higher ratio in the later remodeling phases. CLINICAL SIGNIFICANCE: CBD and THC showed no inhibitory effects on bone healing in a spinal fusion model. Moreover, histologic and gene expression analysis demonstrated that CBD may, in fact, enhance bone healing. Further research is needed to confirm the safe usage of THC and CBD in the post-operative setting following spinal fusions.

Post-operative Patient Portal Messaging is Associated With Return to the Emergency Department After Lumbar Spine Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVE: To explore the association between patients undergoing lumbar spine surgery who message their care team via an electronic patient portal (EPP) post-operatively and emergency department (ED) visits within 90 days of surgery. SUMMARY OF BACKGROUND DATA: Secure patient messaging through electronic patient portals has grown over recent years. Despite its frequent utilization by patients to engage with their care team, its association with clinical outcomes remains unknown in spine surgery. METHODS: This study was approved by our Institutional Review Board. Inclusion criteria were adults who underwent single-stage lumbar spine surgery between January 2016-June 2023. Patients with incomplete information, multi-stage surgeries, and those who died within 90 days of surgery were excluded. Patient sociodemographic, surgical, hospital readmission, and patient-provider engagement data were collected. RESULTS: A total of 13,135 patients were included. A total of 1,711 patients (13%) had a post-operative ED visit, and 4,791 patients (36%) used the patient portal to send a message after surgery. Sending a post-operative patient message after undergoing lumbar spine surgery was associated with an increased likelihood of having an ED visit that does not lead to readmission (1.29 (1.10-1.53), P = 0.002). Patients with high school degrees were more likely to have an ED visit without readmission (1.33 (1.08-1.65), P = 0.008). CONCLUSION: Patients at a higher risk of presenting to the ED post-operatively should be identified and may benefit from additional counseling and access to the care team virtually to limit unnecessary healthcare utilization. Focusing on patients who reach out via EPP messaging post-operatively may be a good target patient group to address first. Future research is needed to investigate the possible health literacy and other socioeconomic barriers affecting these patients so that appropriate, more cost-effective resources can be utilized to avoid clinically unnecessary and costly ED visits.

Assessing the variation and drivers of cost in 1-level lumbar fusion: a time-driven activity-based costing analysis.

BACKGROUND CONTEXT: As value-based health care arrangements gain traction in spine care, understanding the true cost of care becomes critical. Historically, inaccurate cost proxies have been used, including negotiated reimbursement rates or list prices. However, time-driven activity-based costing (TDABC) allows for a more accurate cost assessment, including a better understanding of the primary drivers of cost in 1-level lumbar fusion. PURPOSE: To determine the variation of total hospital cost, differences in characteristics between high-cost and non-high-cost patients, and to identify the primary drivers of total hospital cost in a sample of patients undergoing 1-level lumbar fusion. STUDY DESIGN/SETTING: Retrospective, multicenter (one academic medical center, one community-based hospital), observational study. PATIENT SAMPLE: A total of 383 patients undergoing elective 1-level lumbar fusion for degenerative spine conditions between November 2, 2021 and December 2, 2022. OUTCOME MEASURES: Total hospital cost of care (normalized); preoperative, intraoperative, and postoperative cost of care (normalized); ratio of most to least expensive 1-level lumbar fusion. METHODS: Patients undergoing a 1-level lumbar fusion between November 2, 2021 and December 2, 2022 were identified at two hospitals (one quaternary referral academic medical center and one community-based hospital) within our health system. TDABC was used to calculate total hospital cost, which was also broken up into: pre-, intra-, and postoperative timeframes. Operating surgeon and patient characteristics were also collected and compared between high- and non-high-cost patients. The correlation of surgical time and cost was determined. Multivariable linear regression was used to determine factors associated with total hospital cost. RESULTS: The most expensive 1-level lumbar fusion was 6.8x more expensive than the least expensive 1-level lumbar fusion, with the intraoperative period accounting for 88% of total cost. On average. the implant cost accounted for 30% of the total, but across the patient sample, the implant cost accounted for a range of 6% to 44% of the total cost. High-cost patients were younger (55 years [SD: 13 years] vs.63 years [SD: 13 years], p=.0002), more likely to have commercial health insurance (24 out of 38 (63%) vs. 181 out of 345 (52%), p=.003). There was a poor correlation between time of surgery (i.e., incision to close) and total overall cost (ρ: .26, p<.0001). Increase age (RC: -0.003 [95% CI: -0.006 to -0.000007], p=.049) was associated with decreased cost. Surgery by certain surgeons was associated with decreased total cost when accounting for other factors (p<.05). CONCLUSIONS: A large variation exists in the total hospital cost for patients undergoing 1-level lumbar fusion, which is primarily driven by surgeon-level decisions and preferences (e.g., implant and technology use). Also, being a "fast" surgeon intraoperatively does not mean your total cost is meaningfully lower. As efforts continue to optimize patient value through ensuring appropriate clinical outcomes while also reducing cost, spine surgeons must use this knowledge to lead, or at least be active participants in, any discussions that could impact patient care.

Inpatient opioid use varies by construct length among laminoplasty versus laminectomy and fusion patients.

Background: Laminoplasty (LP) and laminectomy and fusion (LF) are utilized to achieve decompression in patients with symptomatic degenerative cervical myelopathy (DCM). Comparative analyses aimed at determining outcomes and clarifying indications between these procedures represent an area of active research. Accordingly, we sought to compare inpatient opioid use between LP and LF patients and to determine if opioid use correlated with length of stay. Methods: Sociodemographic information, surgical and hospitalization data, and medication administration records were abstracted for patients >18 years of age who underwent LP or LF for DCM in the Mass General Brigham (MGB) health system between 2017 and 2019. Specifically, morphine milligram equivalents (MME) of oral and parenteral pain medication given after arrival in the recovery area until discharge from the hospital were collected. Categorical variables were analyzed using chi-squared analysis or Fisher exact test when appropriate. Continuous variables were compared using Independent samples t tests and Mann-Whitney U tests. Results: One hundred eight patients underwent LF, while 138 patients underwent LP. Total inpatient opioid use was significantly higher in the LF group (312 vs. 260 MME, p=.03); this difference was primarily driven by higher postoperative day 0 pain medication requirements. Furthermore, more LF patients required high dose (>80 MME/day) regimens. While length of stay was significantly different between groups, with LF patients staying approximately 1 additional day, postoperative day 0 MME was not a significant predictor of this difference. When operative levels including C2, T1, and T2 were excluded, the differences in total opioid use and average length of stay lost significance. Conclusions: Inpatient opioid use and length of stay were significantly greater in LF patients compared to LP patients; however, when constructs including C2, T1, T2 were excluded from analysis, these differences lost significance. Such findings highlight the impact of operative extent between these procedures. Future studies incorporating patient reported outcomes and evaluating long-term pain needs will provide a more complete understanding of postoperative outcomes between these 2 procedures.

Clinicians' perceptions around discectomy surgery for lumbar disc herniation: a survey of orthopaedic and neuro-surgeons in Australia and New Zealand.

INTRODUCTION: Understanding practice-based differences in treatment of lumbar disc herniations (LDHs) is vital for reducing unwarranted variation in the delivery of spine surgical health care. Identifying factors that influence surgeons' decision-making will offer useful insights for developing the most cost-effective and safest surgical strategy as well as developing surgeon education materials for common lumbar pathologies. This study was to capture any variation in techniques used by surgeons in Australia and New Zealand (ANZ) region, and perceived complications of different surgical procedures for primary and recurrent LDH (rLDH). MATERIALS AND METHODS: Web-based survey study was emailed to orthopaedic and neurosurgeons who routinely performed spinal surgery in ANZ from Decmber 20, 2018 to February 20, 2020. The response data were analyzed to assess for differences based on geography, practice setting, speciality, practice experience, practice length, and operative volume. RESULTS: Invitations were sent to 150 surgeons; 96 (64%) responded. Most surgeons reported microdiscectomy as their surgical technique of choice for primary LDH (73%) and the first rLDH (72%). For the second rLDH, the preferred choice for most surgeons was fusion surgery (82%). A surgeon's practice setting (academic/private/hybrid) was a statistically significant factor in what surgical procedure was chosen for the first rLDH (P = 0.014). When stratifying based on surgeon experience, there were statisfically significant differences based on the annual volume of spine surgeries performed (perceived reherniation rates following primary discectomy, P = 0.013; perceived reherniation rates following revision surgeries, P = 0.017; perceived intraoperative complications rates following revision surgeries, P = 0.016) and based on the annual volume of lumbar discectomies performed (perceived reherniation rates following revision surgeries, P = 0.022; perceived intraoperative complications rates following revision surgeries, P = 0.036; perceived durotomy rates following primary discectomy, P = 0.023). CONCLUSIONS: Surgeons' annual practice volume and practice setting have significant influences in the selection of surgical procedures and the perception of surgical complications when treating LDHs.

Does Nasal Screening for Methicillin-Resistant Staphylococcus aureus (MRSA) Prevent Deep Surgical Site Infections for Elective Cervical Spinal Fusion?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of this study was to determine the relationship between nasal methicillin-resistant Staphylococcus aureus (MRSA) testing and surgical site infection (SSI) rates in the setting of primary posterior cervical instrumented spine surgery. SUMMARY OF BACKGROUND DATA: Preoperative MRSA screening and decolonization has demonstrated success for some orthopedic subspecialties in prevention of SSIs. Spine surgery, however, has seen varied results, potentially secondary to the anatomic and surgical heterogeneity of the patients included in prior studies. Given that prior research has demonstrated greater propensity for gram positive SSIs in the cervical spine, we sought to investigate if MRSA screening would be more impactful in the cervical spine. MATERIALS AND METHODS: Adult patients undergoing primary instrumented posterior cervical procedures from January 2015 to December 2019 were reviewed for MRSA testing <90 days before surgery, preoperative mupirocin, perioperative antibiotics, and SSI defined as operative incision and drainage (I&D) <90 days after surgery. Logistic regression modeling used SSI as the primary outcome, MRSA screening as primary predictor, and clinical and demographic factors as covariates. RESULTS: This study included 668 patients, of whom MRSA testing was performed in 212 patients (31.7%) and 6 (2.8%) were colonized with MRSA. Twelve patients (1.8%) underwent an I&D. On adjusted analysis, preoperative MRSA testing was not associated with postoperative I&D risk. Perioperative vancomycin similarly had no association with postoperative I&D risk. Notably, 6 patients (50%) grew methicillin sensitive Staphylococcus aureus from intraoperative cultures, with no cases of MRSA. CONCLUSIONS: There was no association between preoperative nasal MRSA screening and SSIs in primary posterior cervical instrumented procedures, nor was there any association between vancomycin or infection rate. Furthermore, there was a preponderance of gram positive infections but none caused by MRSA. Given these findings, the considerable cost and effort associated with MRSA testing in the setting of primary posterior cervical instrumentation may not be justified. Further research should investigate if higher-risk scenarios demonstrate greater utility of preoperative testing.

Magnetic Resonance Imaging Is Inadequate to Assess Cervical Sagittal Alignment Parameters.

STUDY DESIGN: Retrospective radiographic study. OBJECTIVE: To evaluate cervical sagittal alignment measurement reliability and correlation between upright radiographs and magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Cervical sagittal alignment (CSA) helps determine the surgical technique employed to treat cervical spondylotic myelopathy. Traditionally, upright lateral radiographs are used to measure CSA, but obtaining adequate imaging can be challenging. Utilizing MRI to evaluate sagittal parameters has been explored; however, the impact of positional change on these parameters has not been determined. METHODS: One hundred seventeen adult patients were identified who underwent laminoplasty or laminectomy and fusion for cervical spondylotic myelopathy from 2017 to 2019. Two clinicians independently measured the C2-C7 sagittal angle, C2-C7 sagittal vertical axis (SVA), and the T1 tilt. Interobserver and intraobserver reliability were assessed by intraclass correlation coefficient. RESULTS: Intraobserver and interobserver reliabilities were highly correlated, with correlations greater than 0.85 across all permutations; intraclass correlation coefficients were highest with MRI measurements. The C2-C7 sagittal angle was highly correlated between x-ray and MRI at 0.76 with no significant difference ( P =0.46). There was a weaker correlation with regard to C2-C7 SVA (0.48) and T1 tilt (0.62) with significant differences observed in the mean values between the 2 modalities ( P <0.01). CONCLUSIONS: The C2-C7 sagittal angle is highly correlated and not significantly different between upright x-ray and supine MRIs. However, cervical SVA and T1 tilt change with patient position. Since MRI does not accurately reflect the CSA in the upright position, upright lateral radiographs should be obtained to assess global sagittal alignment when planning a posterior-based cervical procedure.

Surgical Intervention is Associated With Improvements in the ASIA Impairment Scale in Gunshot-induced Spinal Injuries of the Thoracic and Lumbar Spine.

STUDY DESIGN: Retrospective cohort study of patients from the National Spinal Cord Injury Statistical Center (NSCISC). OBJECTIVE: The aim was to compare the outcomes of patients with gunshot-induced spinal injuries (GSIs) treated operatively and nonoperatively. SUMMARY OF BACKGROUND DATA: The treatment of neurological deficits associated with gunshot wounds to the spine has been controversial. Treatment has varied widely, ranging from nonoperative to aggressive surgery. METHODS: Patient demographics, clinical information, and outcomes were extracted. Surgical intervention was defined as a "laminectomy, neural canal restoration, open reduction, spinal fusion, or internal fixation of the spine." The primary outcome was the American Spinal Injury Association (ASIA) Impairment Scale. Statistical comparisons of baseline demographics and neurological outcomes between operative and nonoperative cohorts were performed. RESULTS: In total, 961 patients with GSI and at least 1-year follow-up were identified from 1975 to 2015. The majority of patients were Black/African American (55.6%), male (89.7%), and 15-29 years old (73.8%). Of those treated surgically (19.7% of all patients), 34.2% had improvement in their ASIA Impairment Scale score at 1 year, compared with 20.6% treated nonoperatively. Overall, surgery was associated with a 2.0 [95% confidence interval (CI): 1.4-2.8] times greater likelihood of ASIA Impairment Scale improvement at 1 year. Specifically, benefit was seen in thoracic (odds ratio: 2.5; 95% CI: 1.4-4.6) and lumbar injuries (odds ratio: 1.7; 95% CI: 1.1-3.1), but not cervical injuries. CONCLUSIONS: While surgical indications are always determined on an individualized basis, in our review of GSIs, surgical intervention was associated with a greater likelihood of neurological recovery. Specifically, patients with thoracic and lumbar GSIs had a 2.5 and 1.7-times greater likelihood of improvement in their ASIA Impairment Scale score 1 year after injury, respectively, if they underwent surgical intervention.

Selecting the Next Class: The "Virtual Orthopaedic Rotation".

INTRODUCTION: When the COVID-19 pandemic forced the cancellation of visiting subinternships, we pivoted to create a virtual orthopaedic rotation (VOR). The purpose of this study was to assess the effect of the VOR on the residency selection process and determine the role of such a rotation in the future. METHODS: A committee was convened to create a VOR to replace visiting orthopaedic rotations for medical students who are interested in pursuing a career in orthopaedic surgery. The VOR was reviewed and sanctioned by our medical school, but no academic credit was granted. We conducted three 3-week VOR sessions. During each session, virtual rotators participated in regularly scheduled educational conferences and attended an invitation-only daily conference in the evenings that was designed for a medical student audience. In addition, students were paired with faculty and resident mentors in a structured mentorship program. Students' orthopaedic knowledge was assessed using prerotation and postrotation tests. RESULTS: From July to September 2020, 61 students from 37 distinct medical schools participated in the VOR. Notable improvements were observed in prerotation and postrotation orthopaedic knowledge test scores. In postrotation surveys, both students and faculty expressed high satisfaction with the curriculum but less certainty about how well they got to know each other. In the subsequent residency application cycle, 27.9% of the students who participated in the VOR were selected to interview, compared with 8.7% of the total application pool. DISCUSSION: The VOR was a valuable substitute for in-person clinical rotations during the COVID-19 pandemic. Although not likely to be a replacement for conventional away rotations, the VOR is a possible adjunct to in-person clinical rotations in the future.

Open epidural blood patch to augment durotomy repair in lumbar spine surgery: surgical technique and cohort study.

BACKGROUND CONTEXT: Incidental durotomy during elective spine surgery is relatively common. While usually benign and self-limited, it can be associated with morbidity, increased cost, and medicolegal ramifications. Dural repair typically involves performing a primary closure using a suture or dural staple; repairs are then frequently augmented with a sealant, patch, or fat/fascial graft. Although primary repair of an incidental durotomy is standard practice, the ideal secondary sealant or augment choice remains unclear. A wide variety of commercially available dural sealant options exist, and while none have demonstrated consistent superiority, all are associated with single-use costs in the hundreds to thousands of dollars and have concerns regarding swelling, local inflammation, or short-lived dural adherence. PURPOSE: The goal of this study is to compare the results of dural repair augmentation using an open intraoperative epidural blood patch to a hydrogel technique. STUDY DESIGN/SETTING: Retrospective comparative cohort study at an academic referral center PATIENT SAMPLE: Adult patients undergoing lumbar spine surgery from March 2017 to January 2021 who sustained an incidental durotomy. Patients undergoing surgery for infection were excluded. OUTCOME MEASURES: The primary outcome was failure of the repair as determined by a return to the operating room for re-exploration of a persistent cerebrospinal fluid (CSF) leak within 30 days of the index procedure. A secondary outcome was the incidence of a postoperative positional headache, and if present, the method used to obtain resolution. The primary predictor was use of a suture and hydrogel technique ("hydrogel" group), or the use of an epidural blood patch ("EBP" group). METHODS: The method for applying an open epidural blood patch is presented in detail and involves primarily repairing the durotomy followed by allowing whole blood to pool and clot in the operative field until the durotomy is completely covered. This was compared with a group of patients undergoing secondary augmentation with commercially available hydrogel. In both groups, mechanical resistance to CSF leakage was confirmed with direct visualization and a Valsalva maneuver, respectively. Patients were instructed to remain flat until the morning after surgery. Chart review was used for data abstraction on preoperative, demographic, perioperative, and postoperative clinical factors. To compare between the hydrogel and EBP group, Wilcoxon rank-sum testing was used to test for non-parametric comparisons of means, and chi-square testing between binomial data. RESULTS: Of 732 patients during the study period, forty-eight patients met study criteria. Twenty-five patients were in the hydrogel group and 23 in the EBP group. Mean age was 69.3 years (standard error 1.3 years). Patients were predominantly female (n = 31, 64.6%) with a mean BMI of 29.5 (SE 0.8), with no significant baseline differences between the hydrogel and EBP groups. Two patients in the hydrogel group (8.0%) and two in the EBP group (8.7%) had mild positional headaches postoperatively that resolved without intervention within 24 hours. One (4.3%) patient in the EBP group had positional headaches following an initial headache-free period; this patient was returned to the operating room and no evidence of a persistent CSF leak was found despite meticulous exploration. CONCLUSIONS: An open, intraoperatively placed epidural blood patch may be an efficacious and cost-effective way to manage an incidental durotomy. This method merits further study as an allergy-free, no swell, cost-neutral method of dural repair augmentation.

Osteoporosis is under recognized and undertreated in adult spinal deformity patients.

BACKGROUND: Adult spinal deformity (ASD) patients may have osteoporosis, predisposing them to an increased risk for surgical complications. Prior studies have demonstrated that treating osteoporosis improves surgical outcomes. In this study we determine the prevalence of osteoporosis in ASD patients undergoing long spinal fusions and the rate at which osteoporosis is treated. METHODS: ASD patients who frequented either of two major academic medical centers from 2010 through 2019 were studied. All study participants were at least 40 years of age and endured a spinal fusion of at least seven vertebral levels. Medical records were explored for a diagnosis of osteoporosis via ICD-10 code and, if present, whether pharmacological treatment was prescribed. T-tests and chi-squared analyses were used to determine statistical significance. RESULTS: Three hundred ninety-nine patients matched the study's inclusion criteria. Among this group, 131 patients (32.8%) had been diagnosed with osteoporosis prior to surgery. With a mean age of 66.4 years, osteoporotic patients were on average three years older than non-osteoporotic (P=0.002) and more likely to be female (74.8% vs. 61.9%; P=0.01). At the time of surgery, 34.4% of osteoporotic patients were receiving pharmacological treatment. Although not statistically significant, women were more likely to receive medical treatment than men (P=0.07). CONCLUSIONS: The prevalence of osteoporosis in ASD patients undergoing a long spinal fusion is substantially higher than that of the general population. Surgeons should have a low threshold for bone density testing in ASD patients. With only about one-third of osteoporotic patients treated, there is a classic "missed opportunity" in this population.

Development of machine learning and natural language processing algorithms for preoperative prediction and automated identification of intraoperative vascular injury in anterior lumbar spine surgery.

BACKGROUND: Intraoperative vascular injury (VI) may be an unavoidable complication of anterior lumbar spine surgery; however, vascular injury has implications for quality and safety reporting as this intraoperative complication may result in serious bleeding, thrombosis, and postoperative stricture. PURPOSE: The purpose of this study was to (1) develop machine learning algorithms for preoperative prediction of VI and (2) develop natural language processing (NLP) algorithms for automated surveillance of intraoperative VI from free-text operative notes. PATIENT SAMPLE: Adult patients, 18 years or age or older, undergoing anterior lumbar spine surgery at two academic and three community medical centers were included in this analysis. OUTCOME MEASURES: The primary outcome was unintended VI during anterior lumbar spine surgery. METHODS: Manual review of free-text operative notes was used to identify patients who had unintended VI. The available population was split into training and testing cohorts. Five machine learning algorithms were developed for preoperative prediction of VI. An NLP algorithm was trained for automated detection of intraoperative VI from free-text operative notes. Performance of the NLP algorithm was compared to current procedural terminology and international classification of diseases codes. RESULTS: In all, 1035 patients underwent anterior lumbar spine surgery and the rate of intraoperative VI was 7.2% (n=75). Variables used for preoperative prediction of VI were age, male sex, body mass index, diabetes, L4-L5 exposure, and surgery for infection (discitis, osteomyelitis). The best performing machine learning algorithm achieved c-statistic of 0.73 for preoperative prediction of VI (https://sorg-apps.shinyapps.io/lumbar_vascular_injury/). For automated detection of intraoperative VI from free-text notes, the NLP algorithm achieved c-statistic of 0.92. The NLP algorithm identified 18 of the 21 patients (sensitivity 0.86) who had a VI whereas current procedural terminologyand international classification of diseases codes identified 6 of the 21 (sensitivity 0.29) patients. At this threshold, the NLP algorithm had a specificity of 0.93, negative predictive value of 0.99, positive predictive value of 0.51, and F1-score of 0.64. CONCLUSION: Relying on administrative procedural and diagnosis codes may underestimate the rate of unintended intraoperative VI in anterior lumbar spine surgery. External and prospective validation of the algorithms presented here may improve quality and safety reporting.

Caudal Lumbar Disc Herniations Are More Likely to Require Surgery for Symptom Resolution.

STUDY DESIGN: Retrospective study. OBJECTIVES: We examined the impact that location of a lumbar disc herniation has on the likelihood that a patient will require surgery after at least 6 weeks of nonoperative management. METHODS: Using ICD-10 codes M51.26 and M51.27, we identified patients at a single academic institution from 2015 to 2016 who received a diagnosis of primary lumbar radicular pain, had magnetic resonance imaging confirming a lumbar disc herniation, and underwent at least 6 weeks of nonoperative management. Patients experiencing symptoms suggesting cauda equina syndrome or progressive motor deficits were excluded. RESULTS: Five hundred patients met inclusion/exclusion criteria. Twenty-nine (5.8%) had L3-L4 herniations, 245 (49.0%) had L4-L5 herniations, and 226 (45.2%) had L5-S1 herniations. Overall, 451 (90.2%) patients did not undergo surgery within 1 year of diagnosis. Nonsurgical patients had an average herniation size occupying 31.2% of the canal, compared with 31.5% in patients who underwent surgery. While herniation size, age, sex, and race failed to demonstrate a statistical association with the likelihood for surgery, location of disc herniation demonstrated a strong association. L3-L4 and L4-L5 herniations had odds ratios of 0.19 and 0.45, respectively, relative to L5-S1 herniations (P = .0047). Patients were more than twice as likely to require a surgery on an L5-S1 herniation in comparison with an L4-L5 herniation (P < .05). L3-L4 herniations rarely required surgery. CONCLUSIONS: Patients with caudal lumbar disc herniations were more likely to require surgery after at least 6 weeks of conservative management than those with disc herniations in the mid-lumbar spine.

Vancomycin-impregnated calcium sulfate beads compared with vancomycin powder in adult spinal deformity patients undergoing thoracolumbar fusion.

INTRODUCTION: Adult spinal deformity (ASD) surgery patients are at higher risk for surgical site infections (SSIs) due to large incisions, high blood loss, long surgical duration, and extensive instrumentation. The use of vancomycin powder has demonstrated inconsistent results in ASD surgery. Antibiotic-impregnated calcium sulfate beads have been used in arthroplasty and foot and ankle surgery with promising results. The purpose of this study was to provide preliminary data on the use of vancomycin-impregnated calcium sulfate beads in the prevention of SSI following ASD surgery and provide comparisons to the use of vancomycin powder. METHODS: A retrospective chart review was performed for 95 consecutive surgical ASD patients at a tertiary care center from January 2017 until March 2020. Patients received either vancomycin powder (powder group) or vancomycin-impregnated calcium sulfate beads (bead group) intrawound prior to closure. Patient demographics, operative course, and incidence of postoperative infections were recorded. A two-tailed chi-squared test was performed to compare infection rates. RESULTS: Ninety-five patients were included for review. Forty-two patients were in the powder group and 53 patients were in the bead group. The bead group was older (59.8 vs 67.8 years, p < 0.01) with similar BMI and rates of diabetes, smoking, and length of surgery. There were four postoperative SSI in the powder group requiring operative irrigation and debridement and one SSI in the bead group (9.5% vs 1.9%, p = 0.09). All infections occurred in the first 90 days of the postoperative period. CONCLUSION: Preliminary examination of the use of vancomycin-impregnated calcium sulfate beads demonstrated a 1.9% surgical site infection rate in adult spinal deformity surgical patients, which was not significantly different compared with the 9.5% infection rate in patients who received vancomycin powder. Prospective study is needed to determine if the differences found are significant in a larger number of patients.

Laminoplasty-an underutilized procedure for cervical spondylotic myelopathy.

BACKGROUND CONTENT: Cervical laminoplasty (LP) and laminectomy and fusion (LF) are commonly used surgical techniques for cervical spondylotic myelopathy (CSM). Several recent studies have demonstrated superior perioperative metrics and decreased overall costs with LP, yet LF is performed far more often in the United States. PURPOSE: To determine the percentage of patients with CSM who are radiographically candidates for LP. STUDY DESIGN: Retrospective comparative cohort study. PATIENT SAMPLE: Patients >18 years old who underwent LF or LP for CSM at 2 large academic institutions from 2017 to 2019. OUTCOME MEASURES: Candidacy for LP based on radiographic criteria. METHODS: Radiographs were assessed by 2 spine surgeons not involved in the care of the patients to determine the C2-C7 Cobb angle and the presence and extent of cervical instability. Patients with kyphosis >13°, > 3.5 mm of listhesis on static imaging, or > 2.5 mm of motion on flexion-extension or standing-supine films were not considered candidates for LP. Intraclass coefficient (ICC) was calculated to assess the interobserver reliability of angular measurements and the presence of instability. The percentage of patients for whom LP was contraindicated was calculated. RESULTS: One hundred eight patients underwent LF while 142 underwent LP. Of the 108 patients who underwent LF, 79.6% were radiographically deemed candidates for LP, as were all 142 patients who underwent LP. The ICC for C2-C7 alignment was 0.90; there was 97% agreement with respect to the presence of instability. CONCLUSIONS: In 250 patients with CSM, 228 (91.2%) were radiographically candidates for LP. These data suggest that LP may be an underutilized procedure for the treatment for CSM.

Surgeon-level variance in achieving clinical improvement after lumbar decompression: the importance of adequate risk adjustment.

BACKGROUND CONTEXT: Patient-Reported Outcome Measurement Information System (PROMIS) scores are increasingly utilized in clinical care. However, it is unclear if PROMIS can discriminate surgeon performance on an individual level. PURPOSE: The purpose of this study was to examine surgeon-level variance in rates of achieving minimal clinically important difference (MCID) after lumbar decompression. PATIENT SAMPLE: This is a prospective, observational cohort study performed across a healthcare enterprise (two academic medical centers and three community centers). Patients 18 years or older undergoing one- to two-level primary decompression for lumbar disc herniation (LDH) or lumbar spinal stenosis (LSS) were included. OUTCOME MEASURES: The primary outcome was achievement of MCID, using a distribution-based method, on paired PROMIS physical function scores. METHODS: Descriptive statistics were generated to examine the baseline characteristics of the study cohort. Bivariate analyses were used to examine the impact of surgeon-level variance on rates of MCID. Multivariable analyses were used to examine the risk-adjusted impact of surgeon-level variance on rates of MCID. RESULTS: Overall, 636 patients treated by nine surgeons were included. The median patient age was 58 [interquartile range (IQR): 46-70] and 62.3% (n=396) were female. Among all patients, 56.9% (n=362) underwent surgery for LDH. The overall rate of achieving MCID was 75.8% (n=482). Of the surgeons, the median years in practice were 12 (range 4-31) and 55.6% (n=5) were in academic practice settings. On bivariate analysis, patients treated by one of the surgeons had lower rates of achieving MICD (odds ratio=0.37, 95% confidence interval: 0.15-0.91, p=.03). However, on multivariable analysis adjusting for operative indication (LDH vs. LSS), body mass index, number of comorbidities, percent unemployment in patient zip code, and preoperative PROMIS physical function scores, all surgeons were equally likely to obtain MCID. CONCLUSIONS: In this cohort, variance in PROMIS scores after primary lumbar decompression is influenced by patient-related factors and not by individual surgeon. Adequate risk adjustment is needed if ascertaining clinical improvement on an individual surgeon basis. LEVEL OF EVIDENCE: 2.

Development of prediction models for clinically meaningful improvement in PROMIS scores after lumbar decompression.

BACKGROUND: The ability to preoperatively predict which patients will achieve a minimal clinically important difference (MCID) after lumbar spine decompression surgery can help determine the appropriateness and timing of surgery. Patient-Reported Outcome Measurement Information System (PROMIS) scores are an increasingly popular outcome instrument. PURPOSE: The purpose of this study was to develop algorithms predictive of achieving MCID after primary lumbar decompression surgery. PATIENT SAMPLE: This was a retrospective study at two academic medical centers and three community medical centers including adult patients 18 years or older undergoing one or two level posterior decompression for lumbar disc herniation or lumbar spinal stenosis between January 1, 2016 and April 1, 2019. OUTCOME MEASURES: The primary outcome, MCID, was defined using distribution-based methods as one half the standard deviation of postoperative patient-reported outcomes (PROMIS physical function, pain interference, pain intensity). METHODS: Five machine learning algorithms were developed to predict MCID on these surveys and assessed by discrimination, calibration, Brier score, and decision curve analysis. The final model was incorporated into an open access digital application. RESULTS: Overall, 906 patients completed at least one PROMs survey in the 90 days before surgery and at least one PROMs survey in the year after surgery. Attainment of MCID during the study period by PROMIS instrument was 74.3% for physical function, 75.8% for pain interference, and 79.2% for pain intensity. Factors identified for preoperative prediction of MCID attainment on these outcomes included preoperative PROs, percent unemployment in neighborhood of residence, comorbidities, body mass index, private insurance, preoperative opioid use, surgery for disc herniation, and federal poverty level in neighborhood of residence. The discrimination (c-statistic) of the final algorithms for these outcomes was 0.79 for physical function, 0.74 for pain interference, and 0.69 for pain intensity with good calibration. The open access digital application for these algorithms can be found here: https://sorg-apps.shinyapps.io/promis_pld_mcid/ CONCLUSION: Lower preoperative PROMIS scores, fewer comorbidities, and certain sociodemographic factors increase the likelihood of achieving MCID for PROMIS after lumbar spine decompression.

Osteoporosis increases the likelihood of revision surgery following a long spinal fusion for adult spinal deformity.

BACKGROUND: Adult spinal deformity (ASD) can be a debilitating condition that requires surgical intervention. ASD patients often present with osteoporosis, predisposing them to increased rates of instrumentation failure and postoperative fractures, frequent reasons for revision surgery. We hypothesized that the rate and timing of revision surgery are different in osteoporotic and nonosteoporotic patients undergoing long fusions for ASD. To our knowledge, the timing of revision surgeries, in particular, have not previously been explored. PURPOSE: To determine the rate and timing of revision surgery in osteoporotic and nonosteoporotic patients following a long fusion for ASD. STUDY DESIGN: Retrospective comparative study. PATIENT SAMPLE: ASD patients who underwent a long spinal fusion surgery at two large academic medical centers from 2010 to 2019. OUTCOME MEASURES: Occurrence of revision surgery. METHODS: Inclusion criteria were patient age of least 40 years and spinal fusion spanning at least seven levels for ASD. Patient records were reviewed for a diagnosis of osteoporosis as per ICD codes and revision surgery within 2 years of the index procedure. Revision surgery was defined as an unplanned procedure related to the index surgery for the treatment of a spine-related complication. Chi-squared tests comparing demographic data, revision rates, and multiple revisions were conducted. The incidence and prevalence of revision surgeries as a function of time and osteoporotic status were evaluated for significant differences via the Mann-Whitney U and Mantel-Haenszel log rank tests. Finally, a logistic regression analysis was utilized to determine the predictive value of osteoporosis, age, and gender on the likelihood for complications. RESULTS: Three hundred ninety-nine patients matched the study criteria. In the osteoporotic group, 40.5% of patients underwent a revision surgery compared to 28.0% in the nonosteoporotic group (p=.01). The occurrence of multiple revision surgeries following the index procedure was similar in both groups: 8.4% in osteoporotic patients and 8.6% in nonosteoporotic patients. Age and gender were not statistically correlated with the incidence of revision surgery. CONCLUSIONS: ASD patients with osteoporosis have an increased risk of undergoing revision for a surgery-related complication within 2 years of the index procedure. These complications included failure of hardware, pseudoarthrosis, proximal junction failure, and infection, among other issues that required surgical intervention. As others have also highlighted the importance of poor bone density on construct failure, our data further underscore the importance of preoperative osteoporosis surveillance. Though intuitive, further study is needed to demonstrate that improving patients' bone density can decrease the incidence of related complications and the need or revision surgery.

Age Is Just a Number: Patient Age Does Not Affect Outcome Following Surgery for Osteoporotic Vertebral Compression Fractures.

STUDY DESIGN: Retrospective study. OBJECTIVE: Multiple studies have shown that osteoporotic patients are at an increased risk for medical and surgical complications, making optimal management of these patients challenging. The purpose of this study was to determine the relationship between patient age and the likelihood of surgical complications, mortality, and 30-day readmission rates following surgery for osteoporotic vertebral compression fractures (OVCFs). METHODS: A retrospective analysis of the American College of Surgeons National Surgery Quality Improvement Project (ACS-NSQIP) database from 2007 to 2014 identified 1979 patients who met inclusion criteria. A multivariate logistic regression analysis was conducted to calculate odds ratios (OR), with corresponding P values and 95% confidence intervals, of the relationship between age (treated as a continuous variable) and perioperative mortality, surgical complications, and 30-day readmission rates. RESULTS: Younger patients were statistically more likely to endure a minor (OR = 0.98; P = .002) or major complication (OR = 0.97; P = .009). The older a patient was, on the other hand, the higher the likelihood that patient would be readmitted within 30 days of surgery (OR =1.02; P = .004). Mortality within the 30-day perioperative period was not statistically correlated with age. CONCLUSIONS: The impact of age on adverse outcomes following surgery for OVCF is mixed. While younger patients are more likely to endure complications, older patients are more likely to be readmitted within 30 days following surgery. Patient age showed no correlation with mortality rates. In the setting of surgical treatment for an OVCF, a patient's age can help determine the risk of complications and the rate of readmission following intervention.