Impact of age on comparative outcomes of decompression alone versus fusion for L4 degenerative spondylolisthesis.

PURPOSE: To compare the outcomes of decompression alone and fusion for L4-5 DLS in different age cohorts (< 70 years, ≥ 70 years). METHODS: This retrospective cohort study included patients who underwent minimally invasive decompression or fusion for L4-5 DLS and had a minimum of 1-year follow-up. Outcome measures were: (1) patient-reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale back and leg, VAS; 12-Item Short Form Survey Physical Component Score, SF-12 PCS), (2) minimal clinically important difference (MCID), (3) patient acceptable symptom state (PASS), (4) response on the global rating change (GRC) scale, and (5) complication rates. The decompression and fusion groups were compared for outcomes separately in the < 70-year and ≥ 70-year age cohorts. RESULTS: 233 patients were included, out of which 52% were < 70 years. Patients < 70 years showed non-significant improvement in SF-12 PCS and significantly lower MCID achievement rates for VAS back after decompression compared to fusion. Analysis of the ≥ 70-year age cohort showed no significant differences between the decompression and fusion groups in the improvement in PROMs, MCID/PASS achievement rates, and responses on GRC. Patients ≥ 70 years undergoing fusion had significantly higher in-hospital complication rates. When analyzed irrespective of the surgery type, both < 70-year and ≥ 70-year age cohorts showed significant improvement in PROMs with no significant difference. CONCLUSIONS: Patients < 70 years undergoing decompression alone did not show significant improvement in physical function and had significantly less MCID achievement rate for back pain compared to fusion. Patients ≥ 70 years showed no difference in outcomes between decompression alone and fusion.

Improvement following minimally invasive transforaminal lumbar interbody fusion in patients aged 70 years or older compared with younger age groups.

OBJECTIVE: The goal of this study was to assess the outcomes of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in patients ≥ 70 years old and compare them to younger age groups. METHODS: This was a retrospective study of data that were collected prospectively. Patients who underwent primary single-level MI-TLIF were included and divided into 3 groups: age < 60, 60-69, and ≥ 70 years. The outcome measures were as follows: 1) patient-reported outcome measures (PROMs) (i.e., visual analog scale [VAS] for back and leg pain, Oswestry Disability Index [ODI], 12-Item Short-Form Health Survey Physical Component Summary [SF-12 PCS]); 2) minimum clinically important difference (MCID) achievement; 3) return to activities; 4) opioid discontinuation; 5) fusion rates; and 6) complications/reoperations. RESULTS: A total of 147 patients (age < 60 years, 62; 60-69 years, 47; ≥ 70 years, 38) were included. All the groups showed significant improvements in all PROMs at the early (< 6 months) and late (≥ 6 months) time points and there was no significant difference between the groups. Although MCID achievement rates for VAS leg and ODI were similar, they were lower in the ≥ 70-year-old patient group for VAS back and SF-12 PCS. Although the time to MCID achievement for ODI and SF-12 PCS was similar, it was greater in the ≥ 70-year-old patient group for VAS back and leg. There was no significant difference between the groups in terms of return to activities, opioid discontinuation, fusion rates, and complication/reoperation rates. CONCLUSIONS: Although patients > 70 years of age may be less likely and/or take longer to achieve MCID compared to their younger counterparts, they show an overall significant improvement in PROMs, a similar likelihood of returning to activities and discontinuing opioids, and comparable fusion and complication/reoperation rates following MI-TLIF.

Are Grit and Self-Control Associated With Patient-Reported Outcomes Following Spine Surgery?

Background: Grit, defined as perseverance and passion for long-term goals, and self-control, defined as the capacity to regulate impulses in the presence of momentarily gratifying temptations or diversion, have shown to be predictors of professional achievement. Their role in health care outcomes is less well understood. Purpose: We sought to determine whether grit and self-control are associated with patient-reported outcome measures (PROMs) following spine surgery. Methods: We conducted a retrospective review of adult patients who underwent cervical or lumbar procedures by a single fellowship-trained spine surgeon between March 2017 and October 2020. We included patients who underwent anterior cervical discectomy and fusion, cervical disk replacement, minimally invasive laminectomy/laminoplasty (MI-D), or minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) with minimum 1-year follow-up. Grit and self-control scores were collected 1 year after the surgery. PROMs were collected preoperatively and at 6 postoperative timepoints. Grit and self-control were compared between patients who achieved substantial clinical benefit (SCB) in either physical or mental health versus those who did not. The association between grit/self-control and change in PROMs was also assessed. Results: In the 129 patients included in the analysis, we found that patients who achieved SCB in mental health had significantly higher grit scores than those who did not. In bivariate analysis, self-control was associated with greater improvement in leg pain scores at 1-year and 2-year follow-up following an MI-D. For the MI-TLIF cohort, grit was associated with a smaller change in Short Form 12 mental component score at 6 weeks, and self-control was associated with a smaller change in Patient-Reported Outcome Measurement Information System Physical Function at the 6-month timepoint. Grit and self-control were not associated with PROMs at other timepoints. Conclusion: This retrospective review found that grit and self-control were not significantly associated with PROMs at most postoperative timepoints in patients who underwent spine surgery.

Chat Generative Pretraining Transformer Answers Patient-focused Questions in Cervical Spine Surgery.

STUDY DESIGN: Review of Chat Generative Pretraining Transformer (ChatGPT) outputs to select patient-focused questions. OBJECTIVE: We aimed to examine the quality of ChatGPT responses to cervical spine questions. BACKGROUND: Artificial intelligence and its utilization to improve patient experience across medicine is seeing remarkable growth. One such usage is patient education. For the first time on a large scale, patients can ask targeted questions and receive similarly targeted answers. Although patients may use these resources to assist in decision-making, there still exists little data regarding their accuracy, especially within orthopedic surgery and more specifically spine surgery. METHODS: We compiled 9 frequently asked questions cervical spine surgeons receive in the clinic to test ChatGPT's version 3.5 ability to answer a nuanced topic. Responses were reviewed by 2 independent reviewers on a Likert Scale for the accuracy of information presented (0-5 points), appropriateness in giving a specific answer (0-3 points), and readability for a layperson (0-2 points). Readability was assessed through the Flesh-Kincaid grade level analysis for the original prompt and for a second prompt asking for rephrasing at the sixth-grade reading level. RESULTS: On average, ChatGPT's responses scored a 7.1/10. Accuracy was rated on average a 4.1/5. Appropriateness was 1.8/3. Readability was a 1.2/2. Readability was determined to be at the 13.5 grade level originally and at the 11.2 grade level after prompting. CONCLUSIONS: ChatGPT has the capacity to be a powerful means for patients to gain important and specific information regarding their pathologies and surgical options. These responses are limited in their accuracy, and we, in addition, noted readability is not optimal for the average patient. Despite these limitations in ChatGPT's capability to answer these nuanced questions, the technology is impressive, and surgeons should be aware patients will likely increasingly rely on it.

Reliability of Vertebral Pelvic Angles in Assessment of Spinal Alignment.

STUDY DESIGN: Reliability analysis. OBJECTIVES: Vertebral pelvic angles (VPA) are gaining popularity given their ability to describe the shape of the spine. Understanding the reliability and minimal detectable change (MDC) is necessary to determine how these measurement tools should be used in the manual assessment of spine radiographs. Our aim is to assess intra- and interobserver intraclass correlation coefficients (ICC) and the MDC in the use of VPA for assessing alignment in adult spinal deformity (ASD). METHODS: Three independent examiners blindly measured T1, T4, T9, L1, and L4PA twice in ASD patients with a 4-week window after the initial measurements. Patients who had undergone hip or shoulder arthroplasty, fused or transitional vertebrae, or whose hip joints were not visible on radiographs were excluded. Power analysis calculated a minimum sample size of 19. Both intra- and interobserver ICC and MDC, which denotes the smallest detectable change in a true value with 95% confidence, were calculated. RESULTS: Out of the 193 patients, 39 were ultimately included in the study, and 390 measurements were performed by 3 raters. Intraobserver ICC values ranged from .90 to .99. The interobserver ICC was .97, .97, .96, .95, and .92, and the MDC was 5.3°, 5.1°, 4.8°, 4.9°, and 4.1° for T1, T4, T9, L1, and L4PA, respectively. CONCLUSION: All VPAs showed excellent intra- and interobserver reliability, however, the MDC is relatively high compared to typical ranges for VPA values. Therefore, surgeons must be aware that substantial alignment changes may not be detected by a single VPA.

Comparison of the Safety of Inpatient Versus Outpatient Lumbar Fusion : A Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic Review and Meta-analysis. OBJECTIVE: The objective of this study is to synthesize the early data regarding and analyze the safety profile of outpatient lumbar fusion. SUMMARY OF BACKGROUND DATA: Performing lumbar fusion in an outpatient or ambulatory setting is becoming an increasingly employed strategy to provide effective value-based care. As this is an emerging option for surgeons to employ in their practices, the data is still in its infancy. METHODS: This study was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies that described outcomes of inpatient and outpatient lumbar fusion cohorts were searched from PubMed, Medline, The Cochrane Library, and Embase. Rates of individual medical and surgical complications, readmission, and reoperation were collected when applicable. Patient-reported outcomes (PROMs) were additionally collected if reported. Individual pooled comparative meta-analysis was performed for outcomes of medical complications, surgical complications, readmission, and reoperation. PROMs were reviewed and qualitatively reported. RESULTS: The search yielded 14 publications that compared outpatient and inpatient cohorts with a total of 75,627 patients. Odds of readmission demonstrated no significant difference between outpatient and inpatient cohorts [OR=0.94 (0.81-1.11)]. Revision surgery similarly was no different between the cohorts [OR=0.81 (0.57-1.15)]. Pooled medical and surgical complications demonstrated significantly decreased odds for outpatient cohorts compared with inpatient cohorts [OR=0.58 (0.34-0.50), OR=0.41 (0.50-0.68), respectively]. PROM measures were largely the same between the cohorts when reported, with few studies showing better ODI and VAS Leg outcomes among outpatient cohorts compared with inpatient cohorts. CONCLUSION: Preliminary data regarding the safety of outpatient lumbar fusion demonstrates a favorable safety profile in appropriately selected patients, with PROMs remaining comparable in this setting. There is no data in the form of prospective and randomized trials which is necessary to definitively change practice.

The Impact of Preoperative Sagittal Imbalance on Long-term Postoperative Outcomes Following Minimally Invasive Laminectomy.

Background: Postoperative sagittal alignment has been shown to be associated with patient-reported outcome measures (PROMs) following open lumbar decompression procedures, although it is unknown whether preoperative sagittal imbalance affects clinical outcomes of minimally invasive surgical (MIS) decompression only surgery. Purpose: We sought to evaluate the impact of preoperative pelvic incidence-lumbar lordosis (PI-LL) imbalance on PROMs after MIS laminectomy for the treatment of neurogenic claudication symptoms. Methods: We conducted a retrospective cohort study of adult patients undergoing MIS laminectomy for degenerative lumbar spinal stenosis between April 2017 and April 2021 at a single institution. Of the 52 patients included (mean follow-up, 17 months) radiographs were taken prior to surgery and assessed for sagittal alignment parameters. Patients were grouped based on the preoperative PI-LL (balanced vs unbalanced). Changes in PROMs were compared between unbalanced PI-LL and balanced PI-LL groups. Minimal clinically important difference (MCID) for Oswestry Disability Index (ODI) was also assessed. Results: Of the 52 patients, 17 (32.7%) had unbalanced age-adjusted preoperative PI-LL. There was no significant difference found in PROMs between unbalanced and balanced PI-LL groups preoperatively or at final follow-up. Compared with those with unbalanced PI-LL, patients with balanced PI-LL were shown to have no added benefit in achieving MCID for ODI at long-term follow-up and no added benefit in the time to achieving MCID. Conclusion: These retrospective findings suggest that patients with unbalanced preoperative PI-LL may experience significant benefit in long-term clinical outcomes following MIS laminectomy, similarly to those with balanced PI-LL at baseline. The findings also suggest that the presence of sagittal imbalance preoperatively may not appreciably influence the long-term clinical outcomes following MIS laminectomy. Prospective study involving a larger population is warranted.

Impact of Frailty and Cervical Radiographic Parameters on Postoperative Dysphagia Following Anterior Cervical Spine Surgery.

STUDY DESIGN: Retrospective review of a prospectively collected registry. OBJECTIVE: The purpose of the present study was to investigate the impact of frailty and radiographical parameters on postoperative dysphagia after anterior cervical spine surgery (ACSS). SUMMARY OF BACKGROUND DATA: There is a growing body of literature indicating an association between frailty and increased postoperative complications following various surgeries. However, few studies have investigated the relationship between frailty and postoperative dysphagia after anterior cervical spine surgery. MATERIALS AND METHODS: Patients who underwent anterior cervical spine surgery for the treatment of degenerative cervical pathology were included. Frailty and dysphagia were assessed by the modified Frailty Index-11 (mFI-11) and Eat Assessment Tool 10 (EAT-10), respectively. We also collected clinical demographics and cervical alignment parameters previously reported as risk factors for postoperative dysphagia. Multivariable logistic regression was performed to identify the odds ratio (OR) of postoperative dysphagia at early (2-6 weeks) and late postoperative time points (1-2 years). RESULTS: Ninety-five patients who underwent ACSS were included in the study. Postoperative dysphagia occurred in 31 patients (32.6%) at the early postoperative time point. Multivariable logistic regression identified higher mFI-11 score (OR, 4.03; 95% CI: 1.24-13.16; P =0.021), overcorrection of TS-CL after surgery (TS-CL, T1 slope minus C2-C7 lordosis; OR, 0.86; 95% CI: 0.79-0.95; P =0.003), and surgery at C3/C4 (OR, 12.38; 95% CI: 1.41-108.92; P =0.023) as factors associated with postoperative dysphagia. CONCLUSIONS: Frailty, as assessed by the mFI-11, was significantly associated with postoperative dysphagia after ACSS. Additional factors associated with postoperative dysphagia were overcorrection of TS-CL and surgery at C3/C4. These findings emphasize the importance of assessing frailty and cervical alignment in the decision-making process preceding ACSS.

Clinical and Radiological Predictors of Slower and Non-Improvement Following Surgical Treatment of L4-5 Degenerative Spondylolisthesis: Preliminary Results.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To identify the predictors of slower and non-improvement following surgical treatment of L4-5 degenerative lumbar spondylolisthesis (DLS). SUMMARY OF BACKGROUND DATA: There is limited evidence regarding clinical and radiological predictors of slower and non-improvement following surgery for L4-5 DLS. METHODS: Patients who underwent minimally invasive decompression or fusion for L4-5 DLS and had a minimum of 1-year follow-up were included. Outcome measures were: (1) minimal clinically important difference (MCID), (2) patient acceptable symptom state (PASS), and (3) global rating change (GRC). Clinical variables analyzed for predictors were age, gender, body mass index (BMI), surgery type, comorbidities, anxiety, depression, smoking, osteoporosis, and preoperative patient reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale, VAS back and leg; 12-Item Short Form Survey Physical Component Score, SF-12 PCS). Radiological variables analyzed were slip percentage, translational and angular motion, facet diastasis/cyst/orientation, laterolisthesis, disc height, scoliosis, main and fractional curve Cobb angles, and spinopelvic parameters. RESULTS: 233 patients (37% decompression, 63% fusion) were included. At <3 months, high pelvic tilt (PT) (OR 0.92, P 0.02) and depression (OR 0.28, P 0.02) were predictors of MCID non-achievement and GRC non-betterment, respectively. Neither retained significance at >6 months and hence, were identified as predictors of slower improvement. At >6 months, low preoperative VAS leg (OR 1.26, P 0.01) and high facet orientation (OR 0.95, P 0.03) were predictors of MCID non-achievement, high L4-5 slip percentage (OR 0.86, P 0.03) and L5-S1 angular motion (OR 0.78, P 0.01) were predictors of GRC non-betterment, and high preoperative ODI (OR 0.96, P 0.04) was a predictor of PASS non-achievement. CONCLUSIONS: High PT and depression were predictors of slower improvement and low preoperative leg pain, high disability, high facet orientation, high slip percentage, and L5-S1 angular motion were predictors of non-improvement. However, these are preliminary findings and further studies with homogeneous cohorts are required to establish these findings.

Impact of Metabolic Syndrome on Early Postoperative Outcomes After Cervical Disk Replacement: A Propensity-matched Analysis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To compare the demographics, perioperative variables, and complication rates following cervical disk replacement (CDR) among patients with and without metabolic syndrome (MetS). SUMMARY OF BACKGROUND DATA: The prevalence of MetS-involving concurrent obesity, insulin resistance, hypertension, and hyperlipidemia-has increased in the United States over the last 2 decades. Little is known about the impact of MetS on early postoperative outcomes and complications following CDR. METHODS: The 2005-2020 National Surgical Quality Improvement Program was queried for patients who underwent primary 1- or 2-level CDR. Patients with and without MetS were divided into 2 cohorts. MetS was defined, according to other National Surgical Quality Improvement Program studies, as concurrent diabetes mellitus, hypertension requiring medication, and body mass index ≥30 kg/m 2 . Rates of 30-day readmission, reoperation, complications, length of hospital stay, and discharge disposition were compared using χ 2 and Fisher exact tests. One to 2 propensity-matching was performed, matching for demographics, comorbidities, and number of operative levels. RESULTS: A total of 5395 patients were included for unmatched analysis. Two hundred thirty-six had MetS, and 5159 did not. The MetS cohort had greater rates of 30-day readmission (2.5% vs. 0.9%; P =0.023), morbidity (2.5% vs. 0.9%; P =0.032), nonhome discharges (3% vs. 0.6%; P =0.002), and longer hospital stays (1.35±4.04 vs. 1±1.48 days; P =0.029). After propensity-matching, 699 patients were included. All differences reported above lost significance ( P >0.05) except for 30-day morbidity (superficial wound infections), which remained higher for the MetS cohort (2.5% vs. 0.4%, P =0.02). CONCLUSIONS: We identified MetS as an independent predictor of 30-day morbidity in the form of superficial wound infections following single-level CDR. Although MetS patients experienced greater rates of 30-day readmission, nonhome discharge, and longer lengths of stay, MetS did not independently predict these outcomes after controlling for baseline differences in patient characteristics. LEVEL OF EVIDENCE: Level III.

Predictors of Nonhome Discharge After Cervical Disc Replacement.

STUDY DESIGN: Retrospective review of a national database. OBJECTIVE: The aim of this study was to identify the factors that increase the risk of nonhome discharge after CDR. SUMMARY OF BACKGROUND DATA: As spine surgeons continue to balance increasing surgical volume, identifying variables associated with patient discharge destination can help expedite postoperative placement and reduce unnecessary length of stay. However, no prior study has identified the variables predictive of nonhome patient discharge after cervical disc replacement (CDR). METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for patients who underwent primary 1-level or 2-level CDR between 2011 and 2020. Multivariable Poisson regression with robust error variance was employed to identify the predictors for nonhome discharge destination following surgery. RESULTS: A total of 7276 patients were included in this study, of which 94 (1.3%) patients were discharged to a nonhome destination. Multivariable regression revealed older age (OR: 1.076, P <0.001), Hispanic ethnicity (OR: 4.222, P =0.001), BMI (OR: 1.062, P =0.001), ASA class ≥3 (OR: 2.562, P =0.002), length of hospital stay (OR: 1.289, P <0.001), and prolonged operation time (OR: 1.007, P <0.001) as predictors of nonhome discharge after CDR. Outpatient surgery setting was found to be protective against nonhome discharge after CDR (OR: 0.243, P <0.001). CONCLUSIONS: Age, Hispanic ethnicity, BMI, ASA class, prolonged hospital stay, and prolonged operation time are independent predictors of nonhome discharge after CDR. Outpatient surgery setting is protective against nonhome discharge. These findings can be utilized to preoperatively risk stratify expected discharge destination, anticipate patient discharge needs postoperatively, and expedite discharge in these patients to reduce health care costs associated with prolonged length of hospital stay. LEVEL OF EVIDENCE: IV.

Discrepancy between global- and disease-specific outcome measures following lumbar spine surgery.

OBJECTIVE: The aim of this study was to assess the correlation between patient-perceived changes in health and commonly utilized patient-reported outcome measures (PROMs) in lumbar spine surgery. METHODS: This was a retrospective review of prospectively collected data on consecutive patients who underwent lumbar microdiscectomy, lumbar decompression, or lumbar fusion at a single academic institution from 2017 to 2023. Correlation between the global rating of change (GRC) questionnaire, a 5-item Likert scale (much better, slightly better, about the same, slightly worse, and much worse), and PROMs (Oswestry Disability Index, visual analog scale for back and leg pain, 12-Item Short Form Health Survey Physical Component Summary and Mental Component Summary, and PROMIS physical function) was assessed using Spearman's rank correlation coefficients. RESULTS: A total of 1871 patients (397 microdiscectomies, 965 decompressions, and 509 fusions) were included. A majority of patients in each group rated their lumbar condition as much better at each postoperative time point compared with preoperatively and reported improved health status at each postoperative time point compared with the previous follow-up visit. Statistically significant but weak to moderate correlations were found between GRC and change in PROM scores from the preoperative time point. Correlation between GRC and change in PROM scores from the prior visit showed some statistically significant correlations, but the strengths ranged from very weak to weak. CONCLUSIONS: A majority of patients undergoing lumbar microdiscectomy, decompression, or fusion endorsed notable improvements in health status in the early postoperative period and continued to improve at late follow-up. However, commonly used PROMs demonstrated very weak to moderate correlations with patient-perceived changes in overall lumbar spine-related health status as determined by GRC. Therefore, currently used PROMs may not be as sensitive at detecting these changes or may not be adequately reflecting changes in health conditions that are meaningful to patients undergoing lumbar spine surgery.

Psoas Muscle Health is Correlated With Time to Achieve MCID in Patients With Predominant Axial Back Pain Following Decompression Surgery: Early Results.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the impact of psoas muscle health [cross-sectional area (CSA)] on achieving minimal clinically important differences (MCID) in patient-reported outcome measures (PROMs) following laminectomy for patients with predominant back pain (PBP) and leg pain (PLP). SUMMARY OF BACKGROUND DATA: Psoas muscle health is linked to postoperative outcomes in decompression patients, with MRI-based grading of psoas CSA correlating with these outcomes. However, evidence on its impact on symptomatic recovery, measured by PROMs, is lacking. METHODS: One hundred six patients with PBP (VAS back > VAS leg) and 139 patients with PLP (VAS leg > VAS back) who underwent laminectomy from 2017 to 2021 were included. Axial T2 MRI images were analyzed for psoas CSA using a validated method. Based on the lowest-quartile normalized total psoas area (NTPA) thresholds, patients were divided into "good" and "poor" muscle health groups. The correlation analyses were performed between the psoas CSA and changes in PROMs. Kaplan-Meier survival analysis was conducted to determine the probability of achieving MCID as a function of time. RESULTS: Of 106 patients with PBP, 83 (78.3%) had good muscle health, and 23 (21.6%) had poor muscle health. Of 139 patients with PLP, 54 (38.8%) had good muscle health, and 85 (61.1%) had poor muscle health. In the PBP group, older age was associated with poor muscle health (69.70±9.26 vs . 59.92±15.01, P =0.0002). For both cohorts, there were no differences in the rate of MCID achievement for any PROMs between the good and poor muscle health groups. In the PBP group, Kaplan-Meier analysis showed patients with good psoas health achieved MCID-VAS back and Oswestry Disability Index (ODI) in median times of 14 and 42 days ( P =0.045 and 0.015), respectively. CONCLUSION: Good psoas muscle health is linked to faster attainment of MCID, especially in patients with PBP compared with PLP after decompression surgery. LEVEL OF EVIDENCE: III.

Preoperative Physical Therapy is Associated with Decreased Length of Stay and Improved Postoperative Mobility in Patients with Sarcopenia Undergoing Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the relationship between preoperative physical therapy (PT) and postoperative mobility, adverse events (AEs), and length of stay (LOS) among patients with low normalized total psoas area (NTPA) undergoing ASD surgery. SUMMARY OF BACKGROUND DATA: Sarcopenia as defined by low NTPA has been shown to predict poor perioperative outcomes following adult spinal deformity (ASD) surgery. However, there is limited evidence correlating the benefits of PT within the sarcopenic patient population. METHODS: NTPA was analyzed at the L3 and L4 mid-vertebral body on preoperative magnetic resonance imaging (MRI). Receiver operating characteristic (ROC) curve analysis was used to determine gender-specific NTPA cut-off values for predicting perioperative AEs. Patients were categorized as having low NTPA if both L3 and L4 NTPA were below these cut-off values. Perioperative outcomes were compared between patients with low NTPA that underwent documented formal PT within 6 months prior to ASD surgery with those that did not. RESULTS: 103 patients (42 males, 61 females) met criteria for low NTPA for inclusion in the study, of which 42 underwent preoperative PT and 61 did not. The preoperative PT group had a shorter LOS (111.2±37.5 vs. 162.1±97.0 h, P<0.001), higher ambulation distances (feet) on postoperative day (POD) 1 (61.7±50.3 vs. 26.1±69.0, P<0.001), POD 2 (113.2±81.8 vs. 62.1±73.1, P=0.003), and POD 3 (126.0±61.2 vs. 91.2±72.6, P=0.029), and lower rates of total AEs (31.0% vs. 54.1%, P=0.003) when excluding anemia requiring transfusion. Multivariable analysis found preoperative PT to be the most significant predictor of decreased LOS (OR 0.32, P=0.013). CONCLUSION: Sarcopenic patients may benefit from formal preoperative PT prior to undergoing ASD surgery to improve early postoperative mobility, decrease AEs, and decrease LOS. LEVEL OF EVIDENCE: 3.

Temporal Trends of Improvement After Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To analyze temporal trends in improvement after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). SUMMARY OF BACKGROUND DATA: Although several studies have shown that patients improve significantly after MIS TLIF, evidence regarding the temporal trends in improvement is still largely lacking. METHODS: Patients who underwent primary single-level MIS TLIF for degenerative conditions of the lumbar spine and had a minimum of 2-year follow-up were included. Outcome measures were: 1) patient reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale, VAS back and leg; 12-Item Short Form Survey Physical Component Score, SF-12 PCS); 2) global rating change (GRC); 3) minimal clinically important difference (MCID); and 4) return to activities. Timepoints analyzed were preoperative, 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years. Trends across these timepoints were plotted on graphs. RESULTS: 236 patients were included. VAS back and VAS leg were found to have statistically significant improvement compared to the previous timepoint up to 3 months after surgery. ODI and SF-12 PCS were found to have statistically significant improvement compared to the previous timepoint up to 6 months after surgery. Beyond these timepoints, there was no significant improvement in PROMs. 80% of patients reported feeling better compared to preoperative by 3 months. >50% of patients achieved MCID in all PROMs by 3 months. Most patients returned to driving, returned to work, and discontinued narcotics at an average of 21, 20, and 10 days, respectively. CONCLUSIONS: Patients are expected to improve up to 6 months after MIS TLIF. Back pain and leg pain improve up to 3 months and disability and physical function improve up to 6 months. Beyond these timepoints, the trends in improvement tend to reach a plateau. 80% of patients feel better compared to preoperative by 3 months after surgery.

Morbidly Obese Patients Have Similar Clinical Outcomes and Recovery Kinetics After Minimally Invasive Decompression.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To study the impact of class 2/3 obesity (body mass index, BMI >35) on outcomes following minimally invasive decompression. SUMMARY OF BACKGROUND DATA: No previous study has analyzed the impact of class 2/3 obesity on outcomes following minimally invasive decompression. METHODS: Patients who underwent primary minimally invasive decompression were divided into 4 cohorts based on their BMI: normal (BMI 18.5 to <25), overweight (25 to <30), class 1 obesity (30 to <35), and class 2/3 obesity (BMI >35). Outcome measures were: 1) intraoperative variables: operative time, estimated blood loss (EBL); 2) patient reported outcome measures (PROMs) (Oswestry Disability Index, ODI; Visual Analog Scale, VAS back and leg; 12-Item Short Form Survey Physical Component Score, SF-12 PCS); 3) global rating change (GRC), minimal clinically important difference (MCID), and patient acceptable symptom state (PASS) achievement rates; 4) return to activities; and 5) complication and reoperation rates. RESULTS: 838 patients were included (226 normal, 357 overweight, 179 class 1 obesity, 76 class 2/3 obesity). Class 1 and 2/3 obesity groups had significantly greater operative times compared to the other groups. Class 2/3 obesity group had worse ODI, VAS back and SF-12 PCS preoperatively, worse ODI, VAS back, VAS leg and SF-12 PCS at <6 months, and worse ODI and SF-12 PCS at >6 months. However, they had significant improvement in all PROMs at both postoperative timepoints and the magnitude of improvement was similar to other groups. No significant differences were found in MCID and PASS achievement rates, likelihood of betterment on the GRC scale, return to activities, and complication/reoperation rates. CONCLUSIONS: Class 2/3 obese patients have worse PROMs pre- and post-operatively. However, they show similar improvement in PROMs, MCID and PASS achievement rates, likelihood of betterment, recovery kinetics, and complication/reoperation rates as other BMI groups following minimally invasive decompression.

Limited Improvement With Minimally Invasive Lumbar Decompression Alone for Degenerative Scoliosis With Cobb Angle Over 20°: The Impact of Decompression Location.

STUDY DESIGN: Retrospective review of a prospectively collected multisurgeon registry. OBJECTIVE: To evaluate the outcomes of minimally invasive (MI) decompression in patients with severe degenerative scoliosis (DS) and identify factors associated with poorer outcomes. SUMMARY OF BACKGROUND CONTEXT: MI decompression has gained widespread acceptance as a treatment option for patients with lumbar canal stenosis and DS. However, there is a lack of research regarding the clinical outcomes and the impact of MI decompression location in patients with severe DS exhibiting a Cobb angle exceeding 20°. MATERIALS AND METHODS: Patients who underwent MI decompression alone were included and categorized into the DS or control groups based on Cobb angle (>20°). Decompression location was labeled as "scoliosis-related" when the decompression levels were across or between end vertebrae and "outside" when the operative levels did not include the end vertebrae. The outcomes, including the Oswestry Disability Index (ODI), were compared between the propensity score-matched groups for improvement and minimal clinical importance difference (MCID) achievement at ≥1 year postoperatively. Multivariable regression analysis was conducted to identify factors contributing to the nonachievement of MCID in ODI of the DS group at the ≥1-year time point. RESULTS: A total of 253 patients (41 DS) were included in the study. Following matching for age, sex, osteoporosis status, psoas muscle area, and preoperative ODI, the DS groups exhibited a significantly lower rate of MCID achievement in ODI (DS: 45.5% vs. control 69.0%, P =0.047). The "scoliosis-related" decompression (odds ratio: 9.9, P =0.028) was an independent factor of nonachievement of MCID in ODI within the DS group. CONCLUSIONS: In patients with a Cobb angle >20°, lumbar decompression surgery, even in the MI approach, may result in limited improvement of disability and physical function. Caution should be exercised when determining a surgical plan, especially when decompression involves the level between or across the end vertebrae. LEVEL OF EVIDENCE: 3.

Impact of preoperative age-adjusted sagittal imbalance on radiographic and clinical outcomes following 1-level minimally invasive transforaminal lumbar interbody fusion for degenerative spondylolisthesis.

OBJECTIVE: Prior studies investigating the use of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for treatment of degenerative lumbar conditions and concomitant sagittal deformity have not stratified patients by preoperative pelvic incidence (PI)-lumbar lordosis (LL) mismatch, which is the earliest parameter to deteriorate in mild sagittal deformity. Thus, the aim of the present study was to determine the impact of preoperative PI-LL mismatch on clinical outcomes and sagittal balance restoration among patients undergoing MI-TLIF for degenerative spondylolisthesis (DS). METHODS: Consecutive adult patients undergoing primary 1-level MI-TLIF between April 2017 and April 2022 for DS with ≥ 6 months radiographic follow-up were included. Patient-reported outcome measures (PROMs) included the Oswestry Disability Index, visual analog scale (VAS), 12-Item Short-Form Health Survey (SF-12), and Patient-Reported Outcomes Measurement Information System at preoperative, early postoperative (< 6 months), and late postoperative (≥ 6 months) time points. The minimal clinically important difference (MCID) for PROMs was also evaluated. Radiographic parameters included PI, LL, pelvic tilt (PT), and sagittal vertical axis (SVA). Patients were categorized into balanced and unbalanced groups based on preoperative PI-LL mismatch according to age-adjusted alignment goals. Changes in radiographic parameters and PROMs were evaluated. RESULTS: Eighty patients were included (L4-5 82.5%, grade I spondylolisthesis 82.5%, unbalanced 58.8%). Mean clinical and radiographic follow-up were 17.0 and 8.3 months, respectively. The average preoperative PI-LL was 18.8° in the unbalanced group and -3.3° in the balanced group. Patients with preoperative PI-LL mismatch had significantly worse preoperative PT (26.2° vs 16.4°, p < 0.001) and SVA (53.2 vs 9.0 mm, p = 0.001) compared with balanced patients. Patients with preoperative PI-LL mismatch also showed significantly worse PI-LL (16.0° vs 0.54°, p < 0.001), PT (25.9° vs 18.7°, p < 0.001), and SVA (49.4 vs 22.8 mm, p = 0.013) at long-term follow-up. No significant radiographic improvement was observed among unbalanced patients. All patients demonstrated significant improvements in all PROMs (p < 0.05) except for SF-12 mental component score. Achievement of MCID for VAS back score was significantly greater among patients with preoperative PI-LL mismatch (85.7% vs 65.5%, p = 0.045). CONCLUSIONS: Although 1-level MI-TLIF did not restore sagittal alignment in patients with preoperative PI-LL mismatch, patients presenting with DS can expect significant improvement in PROMs following 1-level MI-TLIF regardless of preoperative alignment or extent of correction. Thus, attaining good clinical outcomes in patients with mild sagittal imbalance may not require addressing imbalance directly.

Level-specific comparison of 3D navigated and robotic arm-guided screw placement: an accuracy assessment of 1210 pedicle screws in lumbar surgery.

BACKGROUND CONTEXT: Robotic spine surgery, utilizing 3D imaging and robotic arms, has been shown to improve the accuracy of pedicle screw placement compared to conventional methods, although its superiority remains under debate. There are few studies evaluating the accuracy of 3D navigated versus robotic-guided screw placement across lumbar levels, addressing anatomical challenges to refine surgical strategies and patient safety. PURPOSE: This study aims to investigate the pedicle screw placement accuracy between 3D navigation and robotic arm-guided systems across distinct lumbar levels. STUDY DESIGN: A retrospective review of a prospectively collected registry. PATIENT SAMPLE: Patients undergoing fusion surgery with pedicle screw placement in the prone position, using either via 3D image navigation only or robotic arm guidance. OUTCOME MEASURE: Radiographical screw accuracy was assessed by the postoperative computed tomography (CT) according to the Gertzbein-Robbins classification, particularly focused on accuracy at different lumbar levels. METHODS: Accuracy of screw placement in the 3D navigation (Nav group) and robotic arm guidance (Robo group) was compared using Chi-squared test/Fisher's exact test with effect size measured by Cramer's V, both overall and at each specific lumbosacral spinal level. RESULTS: A total of 321 patients were included (Nav, 157; Robo, 189) and evaluated 1210 screws (Nav, 651; Robo 559). The Robo group demonstrated significantly higher overall accuracy (98.6 vs 93.9%; p<.001, V=0.25). This difference of no breach screw rate was signified the most at the L3 level (No breach screw: Robo 91.3 vs 57.8%, p<.001, V=0.35) followed by L4 (89.6 vs 64.7%, p<.001, V=0.28), and L5 (92.0 vs 74.5%, p<.001, V=0.22). However, screw accuracy at S1 was not significant between the groups (81.1 vs 72.0%, V=0.10). CONCLUSION: This study highlights the enhanced accuracy of robotic arm-guided systems compared to 3D navigation for pedicle screw placement in lumbar fusion surgeries, especially at the L3, L4, and L5 levels. However, at the S1 level, both systems exhibit similar effectiveness, underscoring the importance of understanding each system's specific advantages for optimization of surgical complications.

Predictors for Failure to Respond to Erector Spinae Plane Block Following Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To identify the risk factors associated with failure to respond to erector spinae plane (ESP) block following minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). SUMMARY OF BACKGROUND DATA: ESP block is an emerging opioid-sparing regional anesthetic that has been shown to reduce immediate postoperative pain and opioid demand following MI-TLIF-however, not all patients who receive ESP blocks perioperatively experience a reduction in immediate postoperative pain. METHODS: This was a retrospective review of consecutive patients undergoing 1-level MI-TLIF who received ESP blocks by a single anesthesiologist perioperatively at a single institution. ESP blocks were administered in the OR following induction. Failure to respond to ESP block was defined as patients with a first numerical rating scale (NRS) score post-surgery of >5.7 (mean immediate postoperative NRS score of control cohort undergoing MI TLIF without ESP block). Multivariable logistic regressions were performed to identify predictors for failure to respond to ESP block. RESULTS: A total of 134 patients were included (mean age 60.6 years, 43.3% females). The median and interquartile range (IQR) first pain score post-surgery was 2.5 (0.0-7.5). Forty-nine (36.6%) of patients failed to respond to ESP block. In the multivariable regression analysis, several independent predictors for failure to respond to ESP block following MI TLIF were identified: female sex (OR 2.33, 95% CI 1.04-5.98, P=0.040), preoperative opioid use (OR 2.75, 95% CI 1.03- 7.30, P=0.043), anxiety requiring medication (OR 3.83, 95% CI 1.27-11.49, P=0.017), and hyperlipidemia (OR 3.15, 95% CI 1.31-7.55, P=0.010). CONCLUSIONS: Our study identified several predictors for failure to respond to ESP block following MI TLIF including female sex, preoperative opioid pain medication use, anxiety, and hyperlipidemia. These findings may help inform the approach to counseling patients on perioperative outcomes and pain expectations following MI-TLIF with ESP block. LEVEL OF EVIDENCE: III.