Study Design. Retrospective review of prospectively collected data. Objective. To determine the Oswestry Disability Index (ODI) cutoff for achieving Patient Acceptable Symptom State (PASS) at one year following minimally invasive lumbar spine surgery. Summary of Background Data. An absolute score denoting PASS, rather than a change score denoting minimal clinically important difference (MCID), might be a better metric to assess clinical outcomes. Materials and Methods. Patients who underwent primary minimally invasive transforaminal lumbar interbody fusion or decompression were included. The outcome measure was ODI. The anchor question was the Global Rating Change. "Compared with preoperative, you feel (1) much better, (2) slightly better, (3) same, (4) slightly worse, or (5) much worse." For analysis, it was collapsed to a dichotomous outcome variable (acceptable = response of 1 or 2, unacceptable = response of 3, 4, or 5). Proportion of patients achieving PASS and the ODI cutoff using receiver operating characteristic curve analyses were assessed for the overall cohort as well as subgroups based on age, sex, type of surgery, and preoperative ODI. Differences between the PASS and MCID metrics were analyzed. Results. A total of 137 patients were included. In all, 87% of patients achieved PASS. Patients less than or equal to 65 years and those undergoing fusion were more likely to achieve PASS. The receiver operating characteristic curve analysis revealed an ODI cutoff of 25.2 to achieve PASS (area under the curve. 0.872, sensitivity: 82%, specificity: 83%). The subgroup analyses based on age, sex, and preoperative ODI revealed area under the curve > 0.8 and ODI threshold values consistent between 25.2 and 25.5 (except 28.4 in patients with preoperative ODI > 40). PASS was found to have significantly higher sensitivity compared with MCID (82% vs. 69%, P = 0.01). Conclusions. Patients with ODI <25 are expected to achieve PASS, irrespective of age, sex, and preoperative disability. PASS was found to have significantly higher sensitivity than MCID.

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 onein-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

Study Design. Retrospective review of prospectively collected data. Objective. To determine the Neck Disability Index (NDI) cut-off for achieving patient acceptable symptom state (PASS) at six months following degenerative cervical spine surgery. Summary of Background Data. An absolute score denoting PASS might be a better marker to assess clinical outcomes than a change score denoting minimal clinically important difference. Materials and Methods. Patients who underwent primary anterior cervical decompression and fusion, cervical disk replacement, or laminectomy were included. The outcome measure was NDI. The anchor used to assess PASS achievement at six months was the response on the Global Rating Change: "Compared with preoperative, you feel (1) much better, (2) slightly better, (3) same, (4) slightly worse, or (5) much worse." It was converted to a dichotomous outcome variable (acceptable = response of 1 or 2, unacceptable = response of 3, 4, or 5) for analyses. The overall cohort and subgroups based on age (65 yr and below, above 65 yr), sex, myelopathy, and preoperative NDI ( ≤ 40, > 40) were analyzed for the proportion of patients achieving PASS and the NDI cut-off using receiver operator curve. Results. Seventy-five patients (42 anterior cervical decompression and fusion, 23 cervical disc replacement, 10 laminectomy) were included. 79% of patients achieved PASS. Males, patients with age 65 years and below, preoperative NDI ≤ 40, and absence of myelopathy were more likely to achieve PASS.The receiver operator curve analysis revealed an Oswestry Disability Index cut-off of 21 to achieve PASS (area under the curve, AUC: 0.829, sensitivity: 81%, specificity: 80%). The subgroup analyses based on age, sex, myelopathy, and preoperative NDI revealed AUCs > 0.7 and NDI threshold values consistent between 17 and 23. Conclusions. With an AUC of 0.829, NDI showed an excellent discriminative ability. Patients with NDI ≤ 21 are expected to achieve PASS following degenerative cervical spine surgery.

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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 screwrelated 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.