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.

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.

Practical Answers to Frequently Asked Questions in Anterior Cervical Spine Surgery for Degenerative Conditions.

INTRODUCTION: Surgical counseling enables shared decision making and optimal outcomes by improving patients' understanding about their pathologies, surgical options, and expected outcomes. Here, we aimed to provide practical answers to frequently asked questions (FAQs) from patients undergoing an anterior cervical diskectomy and fusion (ACDF) or cervical disk replacement (CDR) for the treatment of degenerative conditions. METHODS: Patients who underwent primary one-level or two-level ACDF or CDR for the treatment of degenerative conditions with a minimum of 1-year follow-up were included. Data were used to answer 10 FAQs that were generated from author's experience of commonly asked questions in clinic before ACDF or CDR. RESULTS: A total of 395 patients (181 ACDF, 214 CDR) were included. (1, 2, and 3) Will my neck/arm pain and physical function improve? Patients report notable improvement in all patient-reported outcome measures. (4) Is there a chance I will get worse? 13% (ACDF) and 5% (CDR) reported worsening. (5) Will I receive a significant amount of radiation? Patients on average received a 3.7 (ACDF) and 5.5 mGy (CDR) dose during. (6) How long will I stay in the hospital? Most patients get discharged on postoperative day one. (7) What is the likelihood that I will have a complication? 13% (8% minor and 5% major) experienced in-hospital complications (ACDF) and 5% (all minor) did (CDR). (8) Will I need another surgery? 2.2% (ACDF) and 2.3% (CDR) of patients required a revision surgery. (9 & 10) When will I be able to return to work/driving? Most patients return to working (median of 16 [ACDF] and 14 days [CDR]) and driving (median of 16 [ACDF] and 12 days [CDR]). CONCLUSIONS: The answers to the FAQs can assist surgeons in evidence-based patient counseling.

Impact of Preoperative Symptom Duration on Patient-Reported Outcomes Following Cervical Disc Replacement for Cervical Radiculopathy.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To determine the impact of preoperative symptom duration on postoperative functional outcomes following cervical disc replacement (CDR) for radiculopathy. SUMMARY OF BACKGROUND DATA: CDR has emerged as a reliable and efficacious treatment option for degenerative cervical spine pathologies. The relationship between preoperative symptom duration and outcomes following CDR is not well established. METHODS: Patients with radiculopathy without myelopathy who underwent primary 1- or 2-level CDRs were included and divided into shorter (<6 mo) and prolonged (≥6 mo) cohorts based on preoperative symptom duration. Patient-reported outcome measures (PROMs) included Neck Disability Index (NDI), Visual Analog Scale (VAS) Neck and Arm. Change in PROM scores and minimal clinically important difference (MCID) rates were calculated. Analyses were conducted on the early (within 3 mo) and late (6 mo-2 y) postoperative periods. RESULTS: A total of 201 patients (43.6±8.7 y, 33.3% female) were included. In both early and late postoperative periods, the shorter preoperative symptom duration cohort experienced significantly greater change from preoperative PROM scores compared to the prolonged symptom duration cohort for NDI, VAS-Neck, and VAS-Arm. The shorter symptom duration cohort achieved MCID in the early postoperative period at a significantly higher rate for NDI (78.9% vs. 54.9%, P=0.001), VAS-Neck (87.0% vs. 56.0%, P<0.001), and VAS-Arm (90.5% vs. 70.7%, P=0.002). Prolonged preoperative symptom duration (≥6 mo) was identified as an independent risk factor for failure to achieve MCID at the latest timepoint for NDI (OR: 2.9, 95% CI: 1.2-6.9, P=0.016), VAS-Neck (OR: 9.8, 95% CI: 3.7-26.0, P<0.001), and VAS-Arm (OR: 7.5, 95% CI: 2.5-22.5, P<0.001). CONCLUSIONS: Our study demonstrates improved patient-reported outcomes for those with shorter preoperative symptom duration undergoing CDR for radiculopathy, suggesting delayed surgical intervention may result in poorer outcomes and greater postoperative disability. LEVEL OF EVIDENCE: III.

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.

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: 106 patients with PBP (VAS back >VAS leg) and 139 patients with PLP (VAS leg >VAS back) who underwent laminectomy from 2017-2021 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 PBP patients, 83 (78.3%) had good muscle health, 23 (21.6%) had poor muscle health. Of 139 PLP patients, 54 (38.8%) had good muscle health, 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 to PLP after decompression surgery. LEVEL OF EVIDENCE: 3.

Ninety Percent of Patients Are Satisfied With Their Decision to Undergo Spine Surgery for Degenerative Conditions.

STUDY DESIGN: Cross-sectional survey and retrospective review of prospectively collected data. OBJECTIVE: To explore how patients perceive their decision to pursue spine surgery for degenerative conditions and evaluate factors correlated with decisional regret. SUMMARY OF BACKGROUND DATA: Prior research shows that one-in-five older adults regret their decision to undergo spinal deformity surgery. However, no studies have investigated decisional regret in patients with degenerative conditions. METHODS: Patients who underwent cervical or lumbar spine surgery for degenerative conditions (decompression, fusion, or disk replacement) between April 2017 and December 2020 were included. The Ottawa Decisional Regret Questionnaire was implemented to assess prevalence of decisional regret. Questionnaire scores were used to categorize patients into low (<40) or medium/high (≥40) decisional regret cohorts. Patient-reported outcome measures (PROMs) included the Oswestry Disability Index, Patient-reported Outcomes Measurement Information System, Visual Analog Scale (VAS) Back/Leg/Arm, and Neck Disability Index at preoperative, early postoperative (<6 mo), and late postoperative (≥6 mo) timepoints. Differences in demographics, operative variables, and PROMs between low and medium/high decisional regret groups were evaluated. RESULTS: A total of 295 patients were included (mean follow-up: 18.2 mo). Overall, 92% of patients agreed that having surgery was the right decision, and 90% would make the same decision again. In contrast, 6% of patients regretted the decision to undergo surgery, and 7% noted that surgery caused them harm. In-hospital complications (P=0.02) and revision fusion (P=0.026) were significantly associated with higher regret. The medium/high decisional regret group also exhibited significantly worse PROMs at long-term follow-up for all metrics except VAS-Arm, and worse achievement of minimum clinically important difference for Oswestry Disability Index (P=0.007), Patient-Reported Outcomes Measurement Information System (P<0.0001), and VAS-Leg (P<0.0001). CONCLUSIONS: Higher decisional regret was encountered in the setting of need for revision fusion, increased in-hospital complications, and worse PROMs. However, 90% of patients overall were satisfied with their decision to undergo spine surgery for degenerative conditions. Current tools for assessing patient improvement postoperatively may not adequately capture the psychosocial values and patient expectations implicated in decisional regret.

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.

Limited Improvement with Minimally Invasive Lumbar Decompression Alone for Degenerative Scoliosis with Cobb Angle over 20 Degrees: The Impact of Decompression Location.

STUDY DESIGN: Retrospective review of a prospectively collected multi-surgeon 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 degrees. MATERIALS AND METHODS: Patients who underwent MI decompression alone were included and categorized into the DS or control groups based on Cobb angle (>20 degrees). 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 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 non-achievement of MCID in ODI of the DS group at the ≥1 year timepoint. RESULTS: A total of 253 patients (41 DS) were included in the study. Following matching for age, gender, 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 non-achievement of MCID in ODI within the DS group. CONCLUSION: In patients with a Cobb angle>20 degrees, 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.

The Impact of Posterior Intervertebral Osteophytes on Patient-Reported Outcome Measures After L5-S1 Anterior Lumbar Interbody Fusion and Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: (1) To develop a reliable grading system to assess the severity of posterior intervertebral osteophytes and (2) to investigate the impact of posterior intervertebral osteophytes on clinical outcomes after L5-S1 decompression and fusion through anterior lumbar interbody fusion (ALIF) and minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF). BACKGROUND: There is limited evidence regarding the clinical implications of posterior lumbar vertebral body osteophytes for ALIF and MIS-TLIF surgeries and there are no established grading systems that define the severity of these posterior lumbar intervertebral osteophytes. PATIENTS AND METHODS: A retrospective analysis of patients undergoing L5-S1 ALIF or MIS-TLIF was performed. Preoperative and postoperative patient-reported outcome measures of the Oswestry Disability Index (ODI) and leg Visual Analog Scale (VAS) at 2-week, 6-week, 12-week, and 6-month follow-up time points were assessed. Minimal clinically important difference (MCID) for ODI of 14.9 and VAS leg of 2.8 were utilized. Osteophyte grade was based on the ratio of osteophyte length to foraminal width. "High-grade" osteophytes were defined as a maximal osteophyte length >50% of the total foraminal width. RESULTS: A total of 70 consecutive patients (32 ALIF and 38 MIS-TLIF) were included in the study. There were no significant differences between the two cohorts in patient-reported outcome measures or achievement of MCID for Leg VAS or ODI preoperatively or at any follow-ups. On multivariate analysis, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with leg VAS or ODI scores at any follow-up time point. In addition, neither the surgical approach nor the presence of high-grade foraminal osteophytes was associated with the achievement of MCID for leg VAS or ODI at 6 months. CONCLUSION: ALIF and MIS-TLIF are both valid options for treating degenerative spine conditions and lumbar radiculopathy, even in the presence of high-grade osteophytes that significantly occupy the intervertebral foramen. LEVEL OF EVIDENCE: 3.

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.

Preoperative and Postoperative Segmental and Overall Range of Motion in Patients Undergoing Lumbar Spinal Fusion Using HA-Infused PEEK and HA-Treated Titanium Alloy Interbody Cages.

STUDY DESIGN: Retrospective observational radiographic analysis. OBJECTIVE: Determine how single level lumbar interbody fusion (LIF) alters segmental range of motion (ROM) at adjacent levels and decreases overall ROM. METHODS: This study included 54 patients who underwent single-level anterior (ALIF, 39%), thoraco-LIF (TLIF, 26%), posterior LIF (PLIF, 22%), or lateral LIF (LLIF, 13%) (L2-3/L3-4/L4-5/L5-S1: 4%/13%/35%/48%). Segmental ROM from L1-2 to L5-S1 and the overall lumbar ROM (L1-S1) were assessed from preoperative and postoperative flexion-extension radiographs. K-means cluster analysis was used to identify ROM subgroups. RESULTS: The overall L1-S1 ROM decreased 14% (25.5 ± 20.4° to 22.0 ± 17.2°, P = .104) postoperatively. ROM at the fusion level decreased 77% (4.8 ± 5.0° to 1.1 ± 1.1°, P < .001). Caudal adjacent segment ROM decreased 12% (5.2 ± 5.7° to 4.6 ± 4.4°, P = .345) and cranially ROM increased 34% (4.3 ± 5.0° to 5.7 ± 5.7°, P = .05). K-cluster analysis identified 3 distinct clusters (P < .05). Cluster 1 lost more ROM and had less improvement in patient-reported outcomes measures (PROMs) than average. Cluster 2 had less ROM loss than average with worse PROMs improvement. Cluster 3 did not have changes in ROM and better improvement in PROMs than average. Successful fusion was verified in 96% of all instrumented segments with >6 months follow-up (ROM <4°). CONCLUSION: Following single-level L IF, patients should expect a loss of 3.3°, or 14% of overall lumbar motion with increases in ROM of the cranial segment. However, specific clusters of patients exist that experience different relative changes in ROM and PROMs.

Preoperative Disability Influences Effectiveness of Minimal Clinically Important Difference and Patient Acceptable Symptom State in Predicting Patient Improvement Following Cervical Spine Surgery.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To compare the characteristics of the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) metrics when interpreting Neck Disability Index (NDI) following cervical spine surgery. METHODS: Patients who underwent primary cervical fusion, discectomy, or laminectomy were included. NDI and global rating change (GRC) data at 6 months/1 year/2 years were analyzed. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MCID and PASS in predicting improvement on GRC were calculated for the overall cohort and separately for patients with minimal (NDI <30), moderate (NDI 30 - 49), and severe (NDI ≥ 50) preoperative disability. Two groups with patients who achieved PASS but not MCID and patients who achieved MCID but not PASS were analyzed. RESULTS: 141 patients (206 responses) were included. PASS had significantly greater sensitivity for the overall cohort (85% vs 73% with MCID, P = .02) and patients with minimal disability (96% vs 53% with MCID, P < .001). MCID had greater sensitivity for patients with severe disability (78% vs 57% with PASS, P = .05). Sensitivity was not significantly different for PASS and MCID in patients with moderate preoperative disability (83% vs 92%, P = .1). 17% of patients achieved PASS but not MCID and 9% of patients achieved MCID but not PASS. Most of these patients still reported improvement with no significant difference between the 2 groups (89% vs 72%, P = .13). CONCLUSION: PASS and MCID are better metrics for patients with minimal and severe preoperative disability, respectively. Both metrics are equally effective for patients with moderate preoperative disability.

Recovery Kinetics After Cervical Spine Surgery.

STUDY DESIGN: Retrospective review of a prospectively maintained multisurgeon registry. OBJECTIVE: To study recovery kinetics and associated factors after cervical spine surgery. SUMMARY OF BACKGROUND DATA: Few studies have described return to activities cervical spine surgery. This is a big gap in the literature, as preoperative counseling and expectations before surgery are important. MATERIALS AND METHODS: Patients who underwent either anterior cervical discectomy and fusion (ACDF) or cervical disk replacement (CDR) were included. Data collected included preoperative patient-reported outcome measures, return to driving, return to working, and discontinuation of opioids data. A multivariable regression was conducted to identify the factors associated with return to driving by 15 days, return to working by 15 days, and discontinuing opioids by 30 days. RESULTS: Seventy ACDF patients and 70 CDR patients were included. Overall, 98.2% of ACDF patients and 98% of CDR patients returned to driving in 16 and 12 days, respectively; 85.7% of ACDF patients and 90.9% of CDR patients returned to work in 16 and 14 days; and 98.3% of ACDF patients and 98.3% of CDR patients discontinued opioids in a median of seven and six days. Though not significant, minimal (odds ratio (OR)=1.65) and moderate (OR=1.79) disability was associated with greater odds of returning to driving by 15 days. Sedentary work (OR=0.8) and preoperative narcotics (OR=0.86) were associated with decreased odds of returning to driving by 15 days. Medium (OR=0.81) and heavy (OR=0.78) intensity occupations were associated with decreased odds of returning to work by 15 days. High school education (OR=0.75), sedentary work (OR=0.79), and retired/not working (OR=0.69) were all associated with decreased odds of discontinuing opioids by 30 days. CONCLUSIONS: Recovery kinetics for ACDF and CDR are comparable. Most patients return to all activities after ACDF and CDR within 16 days. These findings serve as an important compass for preoperative counseling.

Risk factors for failure to achieve minimal clinically important difference following cervical disc replacement.

BACKGROUND CONTEXT: While cervical disc replacement (CDR) has been emerging as a reliable and efficacious treatment option for degenerative cervical spine pathology, not all patients undergoing CDR will achieve minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) postoperatively-risk factors for failure to achieve MCID in PROMs following CDR have not been established. PURPOSE: To identify risk factors for failure to achieve MCID in Neck Disability Index (NDI, Visual Analog Scale (VAS) neck and arm following primary 1- or 2-level CDRs in the early and late postoperative periods. STUDY DESIGN: Retrospective review of prospectively collected data. PATIENT SAMPLE: Patients who had undergone primary 1- or 2-level CDR for the treatment of degenerative cervical pathology at a single institution with a minimum follow-up of 6 weeks between 2017 and 2022. OUTCOME MEASURES: Patient-reported outcomes: Neck disability index (NDI), Visual analog scale (VAS) neck and arm, MCID. METHODS: Minimal clinically important difference achievement rates for NDI, VAS-Neck, and VAS-Arm within early (within 3 months) and late (6 months to 2 years) postoperative periods were assessed based on previously established thresholds. Multivariate logistic regressions were performed for each PROM and evaluation period, with failure to achieve MCID assigned as the outcome variable, to establish models to identify risk factors for failure to achieve MCID and predictors for achievement of MCID. Predictor variables included in the analyses featured demographics, comorbidities, diagnoses/symptoms, and perioperative characteristics. RESULTS: A total of 154 patients met the inclusion criteria. The majority of patients achieved MCID for NDI, VAS-Neck, and VAS-Arm for both early and late postoperative periods-79% achieved MCID for at least one of the PROMs in the early postoperative period, while 80% achieved MCID for at least one of the PROMs in the late postoperative period. Predominant neck pain was identified as a risk factor for failure to achieve MCID for NDI in the early (OR: 3.13 [1.10-8.87], p-value: .032) and late (OR: 5.01 [1.31-19.12], p-value: .018) postoperative periods, and VAS-Arm for the late postoperative period (OR: 36.63 [3.78-354.56], p-value: .002). Myelopathy was identified as a risk factor for failure to achieve MCID for VAS-Neck in the early postoperative period (OR: 3.40 [1.08-10.66], p-value: .036). Anxiety was identified as a risk factor for failure to achieve MCID for VAS-Neck in the late postoperative period (OR: 6.51 [1.91-22.18], p-value: .003). CDR at levels C5C7 was identified as a risk factor for failure to achieve MCID in NDI for the late postoperative period (OR: 9.74 [1.43-66.34], p-value: .020). CONCLUSIONS: Our study identified several risk factors for failure to achieve MCID in common PROMs following CDR including predominant neck pain, myelopathy, anxiety, and CDR at levels C5-C7. These findings may help inform the approach to counseling patients on outcomes of CDR as the evidence suggests that those with the risk factors above may not improve as reliably after CDR.

Preoperative Disability Influences Effectiveness of MCID and PASS in Predicting Patient Improvement Following Lumbar Spine Surgery.

STUDY DESIGN: Retrospective cohort. SUMMARY OF BACKGROUND DATA: Although minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) are utilized to interpret Oswestry Disability Index (ODI), it is unclear whether there is a clearly better metric between the two and if not, which metric should be utilized when. OBJECTIVE: To compare the characteristics of MCID and PASS when interpreting ODI after lumbar spine surgery. METHODS: Patients who underwent primary minimally invasive transforaminal lumbar interbody fusion or decompression were included. The ODI and global rating change data at 1 year were analyzed. The global rating change was collapsed to a dichotomous outcome variable-(a) improved, (b) not improved The sensitivity, specificity, positive predictive value and negative predictive value of MCID and PASS were calculated for the overall cohort and separately for patients with minimal, moderate, and severe preoperative disability. Two groups with patients who achieved PASS but not MCID and patients who achieved MCID but not PASS were analyzed. RESULTS: Two hundred twenty patients (mean age 62 y, 57% males) were included. PASS (86% vs. 69%) and MCID (88% vs. 63%) had significantly greater sensitivity in patients with moderate and severe preoperative disability, respectively. Nineteen percent of patients achieved PASS but not MCID and 10% of patients achieved MCID but not PASS, with the preoperative ODI being significantly greater in the latter. Most of these patients still reported improvement with no significant difference between the 2 groups (93% vs. 86%). CONCLUSION: Significant postoperative clinical improvement is most effectively assessed by PASS in patients with minimal or moderate preoperative disability and by MCID in patients with severe preoperative disability. Adequate interpretation of ODI using the PASS and MCID metrics warrants individualized application as their utility is highly dependent on the degree of preoperative disability.

Improvement in predominant back pain following minimally invasive decompression for spinal stenosis.

OBJECTIVE: The objective of this study was to assess the outcomes of patients with predominant back pain (pBP) undergoing minimally invasive decompression surgery compared with patients with nonpredominant back pain (npBP). METHODS: This was a retrospective cohort study. Patients were divided into two groups based on the presenting complaint: 1) pBP, defined as visual analog scale (VAS) back pain score > VAS leg pain score; and 2) npBP. Changes in patient-reported outcome measures (PROMs) were compared at the early (< 6 months) and late (≥ 6 months) postoperative time points. Outcomes measures were: 1) PROMs (Oswestry Disability Index [ODI], VAS back and leg pain scores, 12-Item Short-Form Health Survey Physical Component Score [SF-12 PCS], and Patient-Reported Outcomes Measurement Information System Physical Function [PROMIS PF]), and 2) minimal clinically important difference (MCID) achievement rate and time. For the late MCID achievement point, a second analysis was conducted restricting VAS back and leg pain scores only to patients with preoperative scores ≥ 5. RESULTS: Three hundred ninety patients were included (126 with pBP and 264 with npBP). There were no differences in patient demographics and operated levels. There were no differences in preoperative ODI, SF-12 PCS, and PROMIS PF scores. The pBP cohort had a significantly greater preoperative VAS back pain score than the npBP cohort, whereas the npBP cohort had a significantly greater preoperative VAS leg pain score than the pBP cohort. There were no differences in the absolute values or changes in ODI, VAS back pain, SF-12 PCS, and PROMIS PF scores at any time point. There was a significant difference in the early VAS leg pain scores (greater in npBP) that disappeared by the late postoperative time point. There was no difference in the MCID achievement rate in the ODI, SF-12 PCS, or PROMIS PF scores. By the late postoperative time point, 51.2% and 55.3% achieved an MCID on the ODI, 58.1% and 62.7% on the SF-12 PCS, 60% and 67.6% on the PROMIS PF, 81.1% and 73.2% on VAS back pain scores for those with preoperative scores ≥ 5, and 72% and 83.6% on VAS leg pain scores for those with preoperative scores ≥ 5 for the pBP and npBP cohorts, respectively. Additionally, there were no differences in time to MCID achievement for any PROMs. CONCLUSIONS: The pBP and npBP cohorts showed similar improvement in PROMs and MCID achievement rates. This result shows that minimally invasive laminectomy is equally effective for patients presenting with pBP or npBP.

Surgeon Experience Influences Robotics Learning Curve for Minimally Invasive Lumbar Fusion: A Cumulative Sum Analysis.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To analyze the learning curves of three spine surgeons for robotic minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). SUMMARY OF BACKGROUND DATA: Although the learning curve for robotic MI-TLIF has been described, the current evidence is of low quality with most studies being single-surgeon series. MATERIALS AND METHODS: Patients who underwent single-level MI-TLIF with three spine surgeons (years in practice: surgeon 1: 4, surgeon 2: 16, and surgeon 3: two) using a floor-mounted robot were included. Outcome measures were operative time, fluoroscopy time, intraoperative complications, screw revision, and patient-reported outcome measures. Each surgeon's cases were divided into successive groups of 10 patients and compared for differences. Linear regression and cumulative sum (CuSum) analyses were performed to analyze the trend and learning curve, respectively. RESULTS: A total of 187 patients were included (surgeon 1: 45, surgeon 2: 122, and surgeon 3: 20). For surgeon 1, CuSum analysis showed a learning curve of 21 cases with the attainment of mastery at case 31. Linear regression plots showed negative slopes for operative and fluoroscopy time. Both learning phase and postlearning phase groups showed significant improvement in patient-reported outcome measures. For surgeon 2, CuSum analysis demonstrated no discernible learning curve. There was no significant difference between successive patient groups in either operative time or fluoroscopy time. For surgeon 3, CuSum analysis demonstrated no discernible learning curve. Even though the difference between successive patient groups was not significant, cases 11 to 20 had an average operative time of 26 minutes less than cases 1-10), suggesting an ongoing learning curve. CONCLUSIONS: Surgeons who are well-experienced can be expected to have no or minimal learning curve for robotic MI-TLIF. Early attendings are likely to have a learning curve of around 21 cases with the attainment of mastery at case 31. Learning curve does not seem to impact clinical outcomes after surgery. LEVEL OF EVIDENCE: Level 3.

Comparison of Robotics and Navigation for Clinical Outcomes After Minimally Invasive Lumbar Fusion.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To compare navigation and robotics in terms of clinical outcomes after minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). SUMMARY OF BACKGROUND DATA: Although robotics has been shown to have advantages like reduced radiation exposure, greater screw size, and slightly better accuracy over navigation, none of the studies has compared these two modalities in terms of clinical outcomes. METHODS: Patients who underwent single-level MI-TLIF using robotics or navigation and had a minimum of 1-year follow-up were included. The robotics and navigation groups were compared for improvement in patient-reported outcome measures (PROMs), minimal clinically important difference, patient-acceptable symptom state, response on the global rating change scale, and screw-related complication and reoperation rates. RESULTS: A total of 278 patients (143 robotics, 135 navigation) were included. There was no significant difference between the robotics and navigation groups in the baseline demographics, operative variables, and preoperative PROMs. Both groups showed significant improvement in PROMs at below six and six months or above, with no significant difference in the magnitude of improvement between the two groups. Most patients achieved minimal clinically important difference and patient-acceptable symptom state and reported feeling better on the global rating change scale, with no significant difference in the proportions between the robotics and navigation groups. The screw-related complication and reoperation rates also showed no significant difference between the two groups. CONCLUSIONS: Robotics did not seem to lead to significantly better clinical outcomes compared with navigation following MI-TLIF. Although the clinical outcomes may be similar, robotics offers the advantages of reduced radiation exposure, greater screw size, and slightly better accuracy over navigation. These advantages should be considered when determining the utility and cost-effectiveness of robotics in spine surgery. Larger multicenter prospective studies are required in the future to further investigate this subject.

Percutaneous Transforaminal Endoscopic Discectomy Learning Curve: A CuSum Analysis.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To describe the learning curve for percutaneous transforaminal endoscopic discectomy (PTED) and demonstrate its efficacy in treating lumbar disc herniation. SUMMARY OF BACKGROUND DATA: The learning curve for PTED has not yet been standardized in the literature. PATIENTS AND METHODS: Consecutive patients who underwent lumbar PTED by a single surgeon between December 2020 and 2022 were included. Cumulative sum analysis was applied to operative and fluoroscopy time to assess the learning curve. Inflection points were used to divide cases into early and late phases. The 2 phases were analyzed for differences in operative and fluoroscopy time, length of stay, complications, and patient-reported outcome measures (PROMs). Patient characteristics and operative levels were also compared. PROMs entailed the Oswestry Disability Index, Patient-Reported Outcomes Measurement Information System, Visual Analog Scale Back/Leg, and 12-item Short Form Survey at preoperative, early postoperative (<6 mo), and late postoperative (≥6 mo) time points. PROMs between PTED cases and a comparable cohort of tubular microdiscectomy cases, performed by the same surgeon, were compared. RESULTS: Fifty-five patients were included. Cumulative sum analysis indicated that both operative and fluoroscopy time diminished rapidly after case 31, suggesting a learning curve of 31 cases (early phase: n = 31; late phase: n = 24). Late-phase cases exhibited significantly lower operative times (85.7 vs . 62.2 min, P = 0.001) and fluoroscopy times (131.0 vs . 97.2 s, P = 0.001) compared with the early-phase cases. Both early and late-phase cases showed significant improvement in all PROMs. There were no differences in PROMs between the patients who underwent PTED and tubular microdiscectomy. CONCLUSION: The PTED learning curve was found to be 31 cases and did not impact PROMs or complication rates. Although this learning curve reflects the experiences of a single surgeon and may not be broadly applicable, PTED can serve as an effective modality for the treatment of lumbar disc herniation.