Location of the Femoral Nerve in the Lateral Decubitus Versus Prone Position.

STUDY DESIGN: Cadaveric study. OBJECTIVE: To compare the position of the femoral nerve within the lumbar plexus at the L4-L5 disc space in the lateral decubitus vs prone position. METHODS: Seven lumbar plexus specimens were dissected and the femoral nerve within the psoas muscle was identified and marked with radiopaque paint. Lateral fluoroscopic images of the cadaveric specimens in the lateral decubitus vs prone position were obtained. The location of the radiopaque femoral nerve at the L4-L5 disc space was normalized as a percentage of the L5 vertebral body (0% indicates posterior location and 100% indicates anterior location at the L4-L5 disc space). The location of the femoral nerve at L4-L5 in the lateral decubitus vs prone position was compared using a paired t test. RESULTS: In the lateral decubitus position, the femoral nerve was located 28% anteriorly from the posterior edge of the L4-L5 disc space, and in the prone position, the femoral nerve was relatively more posterior, located 18% from the posterior edge of the L4-L5 disc space (P = .037). CONCLUSIONS: The femoral nerve was on average more posteriorly located at the L4-L5 disc space in the prone position compared to lateral decubitus. This more posterior location allows for a larger safe zone at the L4-L5 disc space, which may decrease the incidence of neurologic complications associated with Lateral lumbar interbody fusion in the prone vs lateral decubitus position; however, further studies are needed to evaluate this possible clinical correlation.

Increase in surgeons performing outpatient anterior cervical spine surgery leads to a shift in case volumes over time.

Background: Prior studies have demonstrated an increase in the performance of outpatient anterior cervical surgery. The degree to which this increase is due to volume increase per individual surgeon versus increase in individual surgeons performing outpatient cervical surgery is unknown. Methods: Patients undergoing anterior cervical discectomy and fusion (ACDF) or cervical disk arthroplasty (CDA) between 2010 and 2018 in NY state were identified. As a comparison we also evaluated trends for inpatient ACDF and CDA. Annual outpatient case volumes were calculated and defined as being high (> 20/year), intermediate (>5 and ≤ 20/year) or low (>1 and ≤ 5/year). Descriptive statistics were used to report temporal trends and Poisson regression was used to test for statistical significance. We also analyzed trends in various operative metrics by surgeon volume. Results: In 2010, there were 96 surgeons who performed outpatient ACDF or CDA on a total of 1,855 patients. In 2018, this increased to 253 surgeons performing outpatient ACDF or CDA on a total of 3,372 patients. In comparison, there were 350 surgeons performing 6,783 inpatient cases in 2010 and 376 surgeons performing 6,796 inpatient cases in 2018. The average annual outpatient case volume decreased from 18.8 (95% CI, 13.5 - 24.1) to 12.2 (95% CI, 10.0 - 14.3) surgeries per surgeon. The percentage of surgeons with a high case volume also decreased from 30.2% in 2010 to 10.7% in 2018, whereas the percentage with a low case volume increased (32.3% to 49.8%). Differences between high and low volume surgeons in operative time, length of stay and total charges widened over time. Conclusion: The increase in outpatient anterior cervical surgery appears to be primarily driven by a greater number of surgeons performing ACDF and CDA on an outpatient basis, as opposed to increased case volumes for each surgeon. In contrast, trends for inpatient anterior cervical surgery were stable.

Evaluation of the safety of tranexamic acid use in pediatric patients undergoing spinal fusion surgery: a retrospective comparative cohort study.

BACKGROUND: Pediatric spinal fusion may be associated with significant intraoperative blood loss, leading to complications from transfusion, hypoperfusion and coagulopathy. One emerging strategy to mediate these risks is by utilization of the anti-fibrinolytic agent tranexamic acid (TXA). However, concerns regarding potential adverse reactions, specifically postoperative seizures and thrombotic events, still exist. To assess these risks, we examined the perioperative morbidity of TXA use in a large national database. METHODS: Retrospective data from pediatric patients (age 18 years or younger), discharged between January 2013 to December 2015, who underwent primary or revision posterior spinal fusions, was collected from the Premier Perspective database (Premier, Charlotte, NC). Patients were stratified by TXA use and records were assessed for complications of new onset seizures, strokes, pulmonary embolisms (PE) or deep vein thromboses (DVT) occurring during the perioperative period. RESULTS: In this cohort of 2,633 pediatric patients undergoing posterior spinal fusions, most often to treat adolescent idiopathic scoliosis, 15% received TXA. Overall, adverse events were rare in this patient population. The incidence of seizure, stoke, PE, or DVT in the control group was 0.54% (95% CI, 0.31% to 0.94%) and not significantly different from the TXA group. There was no significant difference in the incidence of DVTs, and no incidences of stroke in either group. There were no new-onset seizures or PEs in patients who received TXA. CONCLUSIONS: The use of TXA was not associated with an increased risk of adverse events including seizure, stroke, PE, and DVT. Our findings support the safety of TXA use in pediatric patients undergoing spinal fusion surgery.

A multicenter study of the 5-year trends in robot-assisted spine surgery outcomes and complications.

Background: Although a growing amount of literature that suggests robots are safe and can achieve comparable outcomes to conventional techniques, much of this literature is limited by small sample sizes and single-surgeon or single center series. Furthermore, it is unclear what the impact of robotic technology has made on operative and clinical outcomes over time. This is the first and largest multicenter study to examine the trends in outcomes and complications after robot-assisted spine surgery over a 5-year period. Methods: Adult (≥18 years old) patients who underwent spine surgery with robot-assistance between 2015 and 2019 at four unique spine centers. The robotic systems used included the Mazor Renaissance, Mazor X, and Mazor Stealth Edition. Patients with incomplete data were excluded from this study. The minimum follow-up was 90 days. Results: A total of 722 adult patients were included (117 Renaissance, 477 X, 128 Stealth). Most patient and operative factors (e.g., sex, tobacco status, total instrumented levels, and pelvic fixation,) were similar across the years. Mean ± standard deviation Charlson comorbidity index (CCI) was 1.5±1.5. The most commonly reported diagnoses included high grade spondylolisthesis (40.6%), degenerative disc disease (18.4%), and degenerative scoliosis (17.6%). Mean (standard deviation) number of instrumented levels was 3.8±3.4. From 2015 to 2019, average robot time per screw improved from 7.2 to 5.5 minutes (P=0.004, R2=0.649). Average fluoroscopy time per screw improved from 15.2 to 9.4 seconds (P=0.002). Rates of both intraoperative screw exchange for misplaced screw (2015-2016: 2.7%, 2019: 0.8%, P=0.0115, R2=0.1316) and robot abandonment (2015-2016: 7.1%, 2019: 1.1%, P=0.011, R2=0.215) improved significantly over time. The incidence of other intraoperative complications (e.g., dural tear, loss of motor/sensory function, blood transfusion) remained consistently low, but similar throughout the years. The length of stay (LOS) decreased by nearly 1 day from 2015 to 2019 (P=0.007, R2=0.779). 90-day reoperation rates did not change significantly. Conclusions: At four institutions among seven surgeons, we demonstrate robot screw accuracy, reliability, operative efficiency, and radiation exposure improved significantly from 2015 to 2019. 90-day complication rates remained low and LOS decreased significantly with time. These findings further validate continued usage of robot-assisted spine surgery and the path toward improved value-based care.

What Is the Comparison in Robot Time per Screw, Radiation Exposure, Robot Abandonment, Screw Accuracy, and Clinical Outcomes Between Percutaneous and Open Robot-Assisted Short Lumbar Fusion?: A Multicenter, Propensity-Matched Analysis of 310 Patients.

STUDY DESIGN: Multicenter cohort. OBJECTIVE: To compare the robot time/screw, radiation exposure, robot abandonment, screw accuracy, and 90-day outcomes between robot-assisted percutaneous and robot-assisted open approach for short lumbar fusion (1- and 2-level). SUMMARY OF BACKGROUND DATA: There is conflicting literature on the superiority of robot-assisted minimally invasive spine surgery to open techniques. A large, multicenter study is needed to further elucidate the outcomes and complications between these two approaches. METHODS: We included adult patients (≥18 yrs old) who underwent robot-assisted short lumbar fusion surgery from 2015 to 2019 at four independent institutions. A propensity score matching algorithm was employed to control for the potential selection bias between percutaneous and open surgery. The minimum follow-up was 90 days after the index surgery. RESULTS: After propensity score matching, 310 patients remained. The mean (standard deviation) Charlson comorbidity index was 1.6 (1.5) and 53% of patients were female. The most common diagnoses included high-grade spondylolisthesis (grade >2) (48%), degenerative disc disease (22%), and spinal stenosis (25%), and the mean number of instrumented levels was 1.5(0.5). The operative time was longer in the open (198 min) versus the percutaneous group (167 min, P value = 0.007). However, the robot time/screw was similar between cohorts (P value > 0.05). The fluoroscopy time/ screw for percutaneous (14.4 s) was longer than the open group (10.1 s, P value = 0.021). The rates for screw exchange and robot abandonment were similar between groups (P value > 0.05). The estimated blood loss (open: 146 mL vs. percutaneous: 61.3 mL, P value < 0.001) and transfusion rate (open: 3.9% vs. percutaneous: 0%, P value = 0.013) were greater for the open group. The 90-day complication rate and mean length of stay were not different between cohorts (P value > 0.05). CONCLUSION: Percutaneous robot-assisted spine surgery may increase radiation exposure, but can achieve a shorter operative time and lower risk for intraoperative blood loss for short-lumbar fusion. Percutaneous approaches do not appear to have an advantage for other short-term postoperative outcomes. Future multicenter studies on longer fusion surgeries and the inclusion of patient-reported outcomes are needed.Level of Evidence: 3.

Does the Use of an Intra-Articular Local Anesthetic Injection During Total Hip Arthroplasty Reduce Patient Reported Pain Scores or Patient Opioid Consumption?

BACKGROUND: During primary total hip arthroplasty (THA), some surgeons use an intra-articular injection (IAI) containing 200 mg ropivacaine to target postoperative pain. There is no clear consensus on the efficacy of an IAI alone. The purpose of this study is to evaluate the effect of a 200 mg ropivacaine IAI on pain scores, opioid consumption, and mobility for primary THA patients. METHODS: We retrospectively reviewed 571 patients who underwent primary THA at a single institution. Patients were grouped according to those who received a 200 mg ropivacaine IAI and those who did not. Primary outcome measures for this study included pain scores, morphine milligram equivalents (MMEs) dosed, distance of ambulation achieved, and time to ambulation. RESULTS: The intervention group reported higher average pain scores with activity than the control group (P = .024). The intervention group also required higher MMEs. When striated by hour, a statistically significant uptick in pain started at 16 hours (P = .0009) and persisted to 28 hours (P = .032) in patients receiving a 200 mg ropivacaine IAI. This correlated with an increase in MMEs seen at hour 24 through 32 (P = .003 to P = .012). Level of ambulation, time to ambulation, and distance ambulated did not differ between groups. An IAI of 200 mg ropivacaine also appeared to lead to higher pain scores and higher opioid doses in males. CONCLUSION: The IAI does not appear to reduce postoperative pain scores or MMEs dosed for THA patients. More research is needed to look at the utilization and efficacy of intra-articular ropivacaine, especially focusing on functional outcomes and gender differences.

Immunoglobulin G4-Negative Inflammatory Pseudotumors of the Pancreas.

Inflammatory pseudotumor (IPT) can occur in any organ, but rarely shows pancreatic involvement. While surgical excision has been recommended as the primary treatment for IPT of the pancreas in the past, some authors suggest observation while medical management often results in regression. Corticosteroids, nonsteroidal anti-inflammatory drugs and immunosuppressive therapy have been used to treat IPTs. Spontaneous regression has also been reported in IPT managed without surgical intervention. A 62-year-old female was evaluated for worsening abdominal pain and a mass in the neck of the pancreas that was identified on ultrasound. Further imaging with magnetic resonance imaging revealed a pancreatic mass with dilated pancreatic duct and an atrophic parenchyma of the pancreatic neck. Her serum tumor markers were not elevated. As this lesion appeared to be resectable pancreatic cancer based on cross-sectional imaging, no biopsy was performed prior to surgical resection. Distal pancreatectomy and splenectomy was recommended and the patient desired to proceed. Her recovery was uneventful with no postoperative complications, including pancreatic fistula. Final pathology revealed a lesion consistent with the diagnosis of immunoglobulin G4 (IgG4)-negative IPT without neoplasm. IPT of the pancreas is a difficult entity to diagnose and treat due to clinical and imaging characteristics closely resembling pancreatic adenocarcinoma. Biopsy with immunohistochemical analysis can be useful in diagnosing IPT; however, symptomatic lesions and concerning findings on cross-sectional imaging may warrant more definitive surgical intervention.