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OBJECTIVE The American Spine Registry (ASR) is a collaborative effort between the American Academy of Orthopaedic Surgeons and the American Association of Neurological Surgeons. The goal of this study was to evaluate how representative the ASR is of the national practice with spinal procedures, as recorded in the National Inpatient Sample (NIS). METHODS The authors queried the NIS and the ASR for cervical and lumbar arthrodesis cases performed during 2017–2019. International Classification of Diseases, 10th Revision and Current Procedural Terminology codes were used to identify patients undergoing cervical and lumbar procedures. The two groups were compared for the overall proportion of cervical and lumbar procedures, age distribution, sex, surgical approach features, race, and hospital volume. Outcomes available in the ASR, such as patient-reported outcomes and reoperations, were not analyzed due to nonavailability in the NIS. The representativeness of the ASR compared to the NIS was assessed via Cohen’s d effect sizes, and absolute standardized mean differences (SMDs) of < 0.2 were considered trivial, whereas > 0.5 were considered moderately large. RESULTS A total of 24,800 arthrodesis procedures were identified in the ASR for the period between January 1, 2017, and December 31, 2019. During the same time period, 1,305,360 cases were recorded in the NIS. Cervical fusions comprised 35.9% of the ASR cohort (8911 cases) and 36.0% of the NIS cohort (469,287 cases). The two databases presented trivial differences in terms of patient age and sex for all years of interest across both cervical and lumbar arthrodeses (SMD < 0.2). Trivial differences were also noted in the distribution of open versus percutaneous procedures of the cervical and lumbar spine (SMD < 0.2). Among lumbar cases, anterior approaches were more common in the ASR than in the NIS (32.1% vs 22.3%, SMD = 0.22), but the discrepancy among cervical cases in the two databases was trivial (SMD = 0.03). Small differences were illustrated in terms of race, with SMDs < 0.5, and a more significant discrepancy was identified in the geographic distribution of participating sites (SMDs of 0.7 and 0.74 for cervical and lumbar cases, respectively). For both of these measures, SMDs in 2019 were smaller than those in 2018 and 2017. CONCLUSIONS The ASR and NIS databases presented a very high similarity in proportions of cervical and lumbar spine surgeries, as well as similar distributions of age and sex, and distribution of open versus endoscopic approach. Slight discrepancies in anterior versus posterior approach among lumbar cases and patient race, and more significant discrepancies in geographic representation were also identified, yet decreasing trends in differences suggested the improving representativeness of the ASR over the course of time and its progressive growth. These conclusions are important to underline the external validity of quality investigations and research conclusions to be drawn from analyses in which the ASR is used.

Longitudinal observational comparative cohorts.The objective of this study is to compare 3 and 12-month radiographic sagittal parameters and patient-reported outcomes (PROs) in patients who underwent 3-level ACDF or a hybrid procedure.Anterior Cervical Discectomy and Fusion (ACDF), Anterior Cervical Corpectomy and Fusion (ACCF), and hybrids (combination ACCF-ACDF) are common procedures used to treat symptomatic cervical spondylosis. Although there is a relative abundance of literature comparing 1-level ACCF versus 2-level ACDF and 2-level ACCF versus 3-level ACDF, detailed comparisons of 3-level ACDF versus hybrid procedures have not been extensively addressed.Patients who underwent a 3-Level ACDF (3L-ACDF, N=47) or 1-Level Corpectomy/1-Level ACDF (Hybrid, N=52) with at least a 12-month post-op data available were identified. Standard demographic, surgical and PROs were collected in addition to preoperative and postoperative radiographic data, including C2 plumb line (C2PL), C2-C7 lordosis (CL), segmental lordosis (SL), and T1 slope (T1S).The 2 cohorts were similar in terms of demographics. At 3 months post-op, CL (9.04° vs. -2.12°, P=0.00) and SL (6.06° vs. -2.26°, P=0.003) were significantly greater in the 3L-ACDF group versus the HYBRID group. This significant difference was maintained at 12 months postoperative for CL [(6.62° vs. -0.60°, P=0.015) but not for SL (2.36° vs. -1.09°, P=0.199)]. There were no differences in PROs between the 2 groups before surgery, at 3 months postoperative or 12 months postoperative. Seven patients required revision surgery in the 1-year study period (1 in the 3L-ACDF, and 6 in the Hybrid P0.001).Three level ACDF resulted in greater C2-C7 lordosis and segmental lordosis postoperatively, which was maintained at 1 year for cervical lordosis. While PROs were similar between the groups, patients with hybrid instrumentation required significantly more revision surgeries than those treated with 3-level ACDF.

Computed tomography (CT) measurement of Hounsfield Units (HU) has been described as a tool for assessing BMD. For surgeons considering a revision lumbar fusion, knowledge of the BMD of the UIV is of value for surgical planning. However, the presence of metal artifact from instrumentation presents a potential confounder, and prior studies have not validated measurements of HU in this setting.To determine if HU can be measured reliably at the supra-adjacent and upper instrumented levels of a lumbar fusion.Retrospective observational cohort PATIENT SAMPLE: Consecutive series of patients who had lumbar CT scans after an instrumented posterior lumbar fusion.Hounsfield Units at the upper instrumented vertebra and levels proximal.We analysed pre- and postoperative CT scans of 50 patients who underwent L2 and distal instrumented lumbar fusion whose scans were no greater than 1 year apart, obtaining HU measurements of analogous axial cuts at the upper instrumented level (immediately caudal to the halo of the pedicle screw), as well as additional control levels above the construct.The HU at the pre-and postoperative UIV exhibited a strong correlation (r=0.917, p.001), as did one (r=0.887, p.001) and two (r=0.853, p.001) levels above the UIV. There were significant but predictable reductions in the postoperative HU compared to preoperative at one (-9.0±26.2) and two (-12.2±30.2) levels above the UIV, as well as T12 (-13.9±42.2). There was no significant difference in HU at the UIV (4.6±34.1).Postoperative HU at the UIV was strongly correlated with and not significantly different from the preoperative HU. Although the HU in the vertebrae proximal to the UIV were slightly lower postoperatively, this change was predictable using a correction factor.

Pain control is essential to successful total shoulder arthroplasty (TSA).This non-blinded, randomized clinical trial compared shoulder pain, narcotic use, interscalene (IS) block application time, and costs in 76 subjects who were randomly assigned to receive either a single injection IS nerve block of 10 cc (133 mg) liposomal bupivacaine mixed with 10 cc of 0.5% bupivacaine (Group 1), or 20 cc of 0.5% ropivacaine direct injection combined with an indwelling IS nerve block catheter delivering 0.2% ropivacaine at a continual 4 cc/h infusion for the initial 3 post-operative days (Group 2). Surgical time, local anesthesia duration, hospital stay length, morphine milligram equivalents (MME) consumed, worst shoulder pain at 24, 48 and 72 h, and complications were recorded. Patient reported function, pain and activity level surveys were completed before, and 6-week post-TSA (P 0.05).Group 1 had less pain 24-h (0.72 ± 0.8 vs. 3.4 ± 2.9, p 0.0001) and 48-h (2.5 ± 2.2 vs. 4.8 ± 2.6, p = 0.005) post-TSA. At 24-h post-TSA, MME consumption was similar (Group 1 = 4.5 ± 6.4 vs. Group 2 = 3.7 ± 3.8, p = 0.54), but was lower for Group 1 at 48 h (0.0 ± 0.0 vs. 0.64 ± 0.99, p = 0.001). Group 2 had longer IS block application time (10.00 ± 4.6 min vs. 4.84 ± 2.7 min, p 0.0001). Only group 2 had a strong relationship between MME consumption over the first 24-h post-TSA and pain 24-h post-TSA (r = 0.76, p 0.0001), a moderate relationship with pain 48-h post-TSA (r = 0.59, P = 0.001), and a weak relationship with pain 72-h post-TSA (r = 0.44, P = 0.02). Significant relationships for these variables were not observed for Group 1 (r ≤ 0.30, p ≥ 0.23). Group 1 IS block costs were less/patient than Group 2 ($190.17 vs. $357.12 USD).A single shot, liposomal bupivacaine interscalene nerve block provided better post-TSA pain control with less narcotic consumption, less time for administration and less healthcare system cost compared to interscalene nerve block using a continuous indwelling catheter.Level I, Prospective, Randomized.

BACKGROUND CONTEXT Excessive use of postoperative imaging after lumbar surgery has been documented, becoming a target for cutting costs. This must be balanced with the patient's need for information and allay their postoperative concerns. PURPOSE To determine the incidence and associated costs of patient interactions with the healthcare system, outside the standard follow up routine, in the first postoperative year. STUDY DESIGN Retrospective longitudinal cohort. PATIENT SAMPLE Consecutive series of 200 patients who underwent lumbar fusions from 2018 to 2019 from a multi-surgeon single tertiary spine center. OUTCOME MEASURES All healthcare encounters: phone calls, office and emergency department visits, and additional testing METHODS A consecutive series of 200 patients who underwent lumbar fusions from 2018 to 2019 were identified. All non-routine healthcare encounters: phone calls, office and emergency department visits, and additional testing were collected. Direct costs for all healthcare services were determined using the Medicare Allowable rates. Indirect costs were determined using local, median income, length of office visits, and distance from the clinic to the patient's home. RESULTS Of 200 patients, 14 with thoracic fusion were excluded. The mean age of the 186 included patients was 58.26 years and 85 (46%) were male. Forty-seven percent (87/186) had only routine postoperative visits and 24 had revision surgery. Seventy-five patients made a total of 102 phone calls, 55 office visits, leading to 38 diagnostic studies none of which led to an additional intervention. Using Medicare Allowable rates, the mean direct cost was $776 per patient and the using a median income of $16/h the mean indirect cost was $124 per patient. There were no differences in the baseline characteristics among the patients who only had routine post-op encounters, had non-routine encounters or had a repeat surgery. CONCLUSIONS Forty percent of the patients undergoing lumbar surgery had a healthcare encounter outside their routine follow up that did not result in additional intervention after their index operation. These potentially unnecessary encounters create additional cost and inconvenience to both the patient and healthcare system. Providing patient reassurance is important and providers should identify ways to reduce associated costs through patient education, virtual visits, or new technologies to monitor patient's postoperative progress.

Patients with advanced pyogenic spondylodiscitis can present with neurologic deficits. However, the prevalence, severity, and outcome of the neurologic deficits are not well known. A systematic review was performed to improve the knowledge of this commonly encountered clinical scenario. The considerable number of severe neurologic deficits in addition to their poor recovery, even after surgical intervention, demonstrates that the early diagnosis of pyogenic spondylodiscitis is crucial. Prompt surgical intervention is likely associated with a greater chance of improvement of neurologic status than nonsurgical treatment.

To provide an up-to-date description of knowledge and pitfalls related to the classification, definition and grading of Modic changes (MC) visualized on magnetic resonance imaging (MRI). State-of-the-art review of current knowledge regarding the definition and grading of MC on MRI. MC on MRI have been reported to be associated with low back pain and disability. However, previous studies have shown heterogeneous results in regards to the impact of MC and its clinical relevance in patients with back pain. MC is a term used with considerable variation in the literature. No strict definition has been provided previously, this has contributed to varying diagnostic inclusion criteria, heterogeneous study populations, and discrepancy in results. A definition of MC and a proposal for grading is provided in this state-of-the-art review. MC are important, clinically relevant findings. However, issues with the nomenclature, definition and grading of these changes need to be addressed. Our current review highlights relevant issues related to MC, and provides a definition and grading score for the term MC that includes the Modic type and the extent of vertebral body involvement. Future studies should seek to validate the MC grading score in clinically relevant populations.

STUDY DESIGN Retrospective single center propensity-matched observational cohort study that included patients who underwent 1- to 3-level lumbar fusion surgery for degenerative conditions. OBJECTIVE To compare 90-day complication rates between robotic-assisted and non-robotic-assisted lumbar spinal fusions in propensity-matched cohorts. SUMMARY OF BACKGROUND DATA A recent administrative database (PearlDiver) study reported increased 30-day complications with the utilization of robotic-assisted enabling technology. METHODS Of 146 robotic-assisted cases that met inclusion criteria, 114 were successfully propensity matched to 114 patients from 214 cases who had 1 to 3 level lumbar fusion without robotic assistance based on age, sex, body mass index, smoking status, American Society of Anesthesiologist grade, number of surgical levels, primary versus revision, and surgical approach (posterior-only or anterior-posterior). We excluded tumor, trauma, infection, or deformity cases. Outcomes included surgical and medical (major/minor) complications at intraoperative, immediately postoperative, 30- and 90-day postoperative intervals, including reoperations, and readmissions within 90 days. RESULTS All cause intraoperative complication rates were similar between non-robotic-assisted (5.3%) and robotic-assisted groups (10.5%, P = 0.366). Immediate postoperative medical complication rate was also similar between non-robotic-assisted (6.1%) and robotic-assisted groups (1.8%, P = 0.089). Thirty-day complication rates, 90-day complication rates, reoperation rates, and readmission rates showed no difference between non-robotic-assisted and robotic-assisted groups. There was no difference between return to OR for infection between the cohorts (non-robotic-assisted: 6 [5%] vs. robotic-assisted: 1 [0.8%], P = 0.119). There was however improved length of stay (LOS) in the robotic-assisted group compared with non-robotic-assisted group (2.5 vs. 3.17 days, P = 0.018). CONCLUSION In propensity-matched cohorts, patients undergoing 1- to 3-level robotic-assisted posterior lumbar fusion for degenerative conditions did not have increased 90-day complication rate, and had a shorter length of stay compared with non-robotic-assisted patients. There findings differ from a prior administrative database study as the robotic-assisted group in the current study had 0% return to OR for malpositioned screws and 0.8% return to OR for infection.Level of Evidence: 2.

PURPOSE Retrospective observational cohort study of primary adult spinal deformity (ASD) surgery during the transitional period prior to and after the implementation of Enhanced Surgical Recovery (ESR) at a single center. We sought to determine if ESR reduces in-hospital and 90-day post-operative opioid consumption for ASD surgery. METHODS We evaluated patients undergoing primary ASD surgery in the transition period prior to (N = 29) and after (N = 56) adoption of ESR, comparing in-hospital and 90-day post-operative opioid consumption. Regression analysis was used to control for confounders including age, number of surgical levels, surgical approach, staged vs same-day surgery, insurance type and pre-op opioid use. RESULTS Mean age of the cohort was 53 years with 57 (60%) females. Regression analysis showed that pre-operative opioid use and number of levels fused were associated with higher in-hospital and 90-day post-operative opioid consumption, while use of ESR was associated with lower in-hospital and 90-day post-operative opioid consumption. Secondary analysis showed that patients on ESR ambulated earlier (0.6 days vs 1.1, p = 0.028) and had their urinary catheter removed earlier (2.7 days vs 3.9, p = 0.006) compared to non-ESR patients. CONCLUSIONS ESR was associated with a significantly decreased in-hospital and 90-day post-operative opioid consumption and earlier mobilization with earlier urinary catheter removal in patients undergoing primary ASD surgery. These results demonstrate ESR's potential to improve outcomes in ASD perioperative care. LEVEL OF EVIDENCE 3.

Background The present study is a secondary analysis of data from a randomized, double-blind, placebo controlled clinical trial. Patients undergoing decompression and non-instrumented lumbar arthrodesis may have initial bone loss after surgery, increasing their fracture risk. The aim of this analysis is to determine whether short term systemic Teriparatide has a beneficial effect on Bone Mineral Density (BMD) in patients 60 years and older undergoing non-instrumented lumbar arthrodesis. Method Patients were 87 Danish patients eligible for spinal decompression and non-instrumented arthrodesis, who received either 20 micrograms Teriparatide (N=43) or placebo (N=44) daily for 3 months starting prior to surgery. Randomization and allocation were computer-generated. Outcome measures were BMD and Patient reported Outcome measures (PROs) containing Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for leg pain. DXA scans were performed preoperatively and at 1,3,6 and 12 months after surgery. PROs were collected at the same time points aside at 1 month after surgery. ANCOVA comparing Lumbar Spine BMD and Hip BMD in Teriparatide vs Placebo with gender, weight, age and baseline BMD as covariates were performed. Results There was some improvement in BMD in the Teriparatide group compared to placebo at 3 months after surgery, but not sustained at 6 and 12 months. There was a loss of Lumbar Spine BMD at 1 month after surgery in both groups. Conclusion Systemic Teriparatide provided a short term beneficial effect on BMD compared to placebo in patients undergoing decompression and non instrumented lumbar arthrodesis. There was an initial rapid bone loss 1 month after surgery in both groups.

Study Design.This was a dual-center study over an eight-year period on patients undergoing single level fusion surgery with either posterior- (PLIF) or transforaminal lumbar interbody fusion (TLIF). We analyzed prospectively collected pre- and postoperative data from the national Danish surgical spine database (DaneSpine).Objective.The aim of this study was to compare clinical and patient-reported outcome (PRO) 2 years after TLIF or PLIF in patients with symptomatic lumbar mechanical disc degeneration.Summary of Background Data.PLIF and TLIF are well-described techniques for treating lumbar mechanical disc degeneration but whether the theoretical differences between the two techniques translate to different clinical outcomes is unknown.Methods.The primary outcome was Oswestry Disability Index (ODI) score at 2-year follow-up. Secondary outcome measures were scores on the European Quality of Life-5 Dimensions (EQ-5D) and visual analog scale (VAS) and the rate of intraoperative complications. To minimize baseline differences between the groups, propensity-score matching was employed in a 1:1 fashion, balancing the groups on preoperative factors including age, sex, back and leg pain, ODI, EQ-5D, and previous spine surgery.Result.The matched cohort included 211 patients in each cohort. There was no significant difference between the groups in the mean score on the ODI at two years (PLIF: 33 ± 20 vs. TLIF: 35 ± 20, P = 0.328). We found no statistically significant differences in EQ-5D score (0.54 ± 0.35 vs. 0.51 ± 0.34, P = 0.327), VAS score for back pain (47 ± 32 vs. 48 ± 29, P = 0.570) or leg pain (42 ± 33 vs. 41 ± 32, P = 0.936) between the PLIF and TLIF groups, respectively, at 2-year follow-up. Dural tears occurred in 9.5% in the PLIF group and 1.9% in the TLIF group (P = 0.002) corresponding to a relative risk of 5.0 (95% CI 1.7-14.4).Conclusion.We found no significant difference in PRO at 2-year follow-up between PLIF and TLIF for the treatment of lumbar disc degeneration. PLIF is associated with a five times higher risk of dural tears.Level of Evidence: 3.

Background Lumbar disc herniation (LDH) is a common problem. When surgical treatment is required, the intervention is typically decompression without fusion. Successful return-to-work (RTW) is a standard expectation with these limited procedures. Occasionally, the size or location of the disc herniation suggests the need for fusion, but the inability to RTW is a significant concern in these cases. The purpose of this study is to determine if the addition of lumbar fusion, as compared to decompression alone, will substantially diminish RTW in patients with lumbar disc herniation. Methods This is a longitudinal cohort study using prospectively collected data from the Quality and Outcomes Database (QOD). Patients with LDH, eligible to RTW (not retired, a student, or on disability) with complete 12-month follow-up data, were identified. Standard demographic and surgical variables, patient-reported outcomes (PROs), and RTW status at 3 and 12 months were collected. Results Of the 5062 patients identified, 4560 (90%) had decompression alone and 502 (10%) had a concurrent fusion. Age and gender were similar in the two groups. The fusion group had worse back pain (NRS 6.52 vs. 5.96) and less leg pain (6.31 vs. 7.01) at baseline compared to the no fusion group. Statistically significant improvement in all PROs was seen in both groups. RTW at 3 months post-op was seen in 85% of decompression cases and 66% of cases with supplemental fusion. At 12 months post-op, RTW increased to 93% and 82%, respectively. Conclusion The need for fusion in LDH cases is unusual, seen in only 10% of cases in this series. The addition of fusion decreased the RTW rate from 85 to 66% at 3 months and from 93 to 82% at 12 months post-op. While the difference is significant, the ultimate deterioration in RTW may be less than anticipated. A reasonable RTW rate can still be expected in the rare patient who requires fusion as part of their treatment for LDH.

Adult spinal deformity; Patient reported outcomes; Spinal deformity surgery Deformidad espinal en el adulto; Resultados informados por el paciente; Cirugía de deformidad espinal Deformitat espinal de l'adult; Resultats informats pel pacient; Cirurgia de deformitat espinal Study Design: Prospective cohort. Objective: To prospectively evaluate PROs up to 5-years after complex ASD surgery. Methods: The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers. Inclusion criteria was Cobb angle of >80°, corrective osteotomy for congenital or revision deformity, and/or 3-column osteotomy. The following PROs were measured prospectively at intervals up to 5-years postoperative: ODI, SF36-PCS/MCS, SRS-22, NRS back/leg. Among patients with 5-year follow-up, comparisons were made from both baseline and 2-years postoperative to 5-years postoperative. PROs were analyzed using mixed models for repeated measures. Results: Seventy-seven patients (28.3%) had 5-year follow-up data. Comparing baseline to 5-year data among these 77 patients, significant improvement was seen in all PROs: ODI (45.2 vs. 29.3, P < 0.001), SF36-PCS (31.5 vs. 38.8, P < 0.001), SF36-MCS (44.9 vs. 49.1, P = 0.009), SRS-22-total (2.78 vs. 3.61, P < 0.001), NRS-back pain (5.70 vs. 2.95, P < 0.001) and NRS leg pain (3.64 vs. 2.62, P = 0.017). In the 2 to 5-year follow-up period, no significant changes were seen in any PROs. The percentage of patients achieving MCID from baseline to 5-years were: ODI (62.0%) and the SRS-22r domains of function (70.4%), pain (63.0%), mental health (37.5%), self-image (60.3%), and total (60.3%). Surprisingly, mean values (P > 0.05) and proportion achieving MCID did not differ significantly in patients with major surgery-related complications compared to those without. Conclusions: After complex ASD surgery, significant improvement in PROs were seen at 5-years postoperative in ODI, SF36-PCS/MCS, SRS-22r, and NRS-back/leg pain. No significant changes in PROs occurred during the 2 to 5-year postoperative period. Those with major surgery-related complications had similar PROs and proportion of patients achieving MCID as those without these complications. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was funded by AO Spine through the AO Spine Knowledge Forum Deformity, the Scoliosis Research Society (SRS), and Norton Healthcare. AO Spine Knowledge Forum Deformity is a focused group of international deformity experts. AO Spine is a clinical division of the AO Foundation, which is an independent medically-guided not-for-profit organization. Study support was provided directly through the AO Spine Research Department and the AO Innovation Translation Center, Clinical Evidence.

Study design Cross-sectional retrospective observational study. Objective To evaluate the reliability and clinical utility of the Modic changes (MC) grading score. Method Patients from the Danish national spine registry, DaneSpine, scheduled for lumbar discectomy were identified. MRI of patients with MC were graded based on vertical height involvement: Grade A (50%). All MRIs were reviewed by 2 physicians to evaluate the reliability of the MC grade. Results Of 213 patients included, 142 patients had MC, 71 with MC-1 and 71 with MC-2; 34% were Grade A, 45% were Grade B, and 21% were Grade C. MC grade demonstrated substantial intra-rater (κ = .68) and inter-rater (κ = .61) reliability. A significantly higher proportion (n = 40, 57%) of patients with MC-1 had a severe MC grade compared to patients with MC-2 (n = 30, 43%, P < .001). Severe MC grade was associated with the presence of severe lumbar disc degeneration (DD) (Pfirrmann grade = V, P = .024), worse preoperative ODI (52.49 vs 44.17, P = .021) and EQ-5D scores (.26 vs .46, P = .053). MC alone including type was not associated with a significant difference in patient-reported outcomes ( P > .05). Conclusion The MC grade score was demonstrated to have substantial intra- and inter-observer reliability. Severe MC grade was associated with both severe DD and MC type, being more prevalent in patients with MC-1. The MC grade was also significantly associated with worse disability and reduced health-related quality of life. Results from the study suggest that MC grade is more clinically important than MC type.

BACKGROUND: Novel methods of bone density assessment using computed tomography (CT) and magnetic resonance imaging (MRI) have been increasingly reported in the spine surgery literature. Correlations between these newer measurements and traditional Dual-Energy X-ray Absorptiometry (DEXA) is not well known. The purpose of this study is to perform an updated systematic review of correlations between bone mineral density (BMD) from CT or MRI and DEXA. METHODS: Articles published between 2011 and 2021 that reported correlations between the CT-HU or MRI measurements to DEXA t-scores or BMD of lumbar spine or hip were included in this systematic review. RESULTS: A total of 25 studies (15 CT, 10 MRI) met the inclusion criteria with a total number of 2,745 patients. The pooled correlation coefficient of spine CT-HU versus spine DEXA, spine CT-HU versus hip DEXA and spine CT-HU versus lowest t-score were 0.60, 0.50 and 0.60 respectively. Regarding spine DEXA parameters, the pooled r(2) for spine CT-HU versus spine t-score was 0.684 and spine CT-HU versus spine BMD was 0.598. Furthermore, in patients undergoing spine surgery in four studies, the pooled correlation between spine CT and spine DEXA was (r(2): 0.64). In MRI studies, the pooled r(2) of spine MRI versus spine DEXA and spine MRI versus hip DEXA were -0.41 and -0.44 respectively. CONCLUSIONS: CT-HU has stronger correlations with DEXA than MRI measurements. Lumbar CT-HU has the highest pooled correlation (r(2) = 0.6) with both spine DEXA and lowest skeletal t-score followed by lumbar CT-HU with hip DEXA (r(2) = 0.5) and lumbar MRI with hip (r(2) = 0.44) and spine (r(2) = 0.41) DEXA. Both imaging modalities achieved only a moderate correlation with DEXA. Few studies in both modalities have investigated the correlation in spine surgery populations and the available data shows that the correlations are worse in the degenerative spine population. A careful interruption of CT HU and MRI measurement when evaluation of BMD as they only moderately correlated with DEXA scores. At this time, it is unclear which modality is a better predictor of mechanical complications and clinical outcomes in spine surgery patients.

OBJECTIVE Although short-term adult symptomatic lumbar scoliosis (ASLS) studies favor operative over nonoperative treatment, longer outcomes are critical for assessment of treatment durability, especially for operative treatment, because the majority of implant failures and nonunions present between 2 and 5 years after surgery. The objectives of this study were to assess the durability of treatment outcomes for operative versus nonoperative treatment of ASLS, to report the rates and types of associated serious adverse events (SAEs), and to determine the potential impact of treatment-related SAEs on outcomes. METHODS The ASLS-1 (Adult Symptomatic Lumbar Scoliosis–1) trial is an NIH-sponsored multicenter prospective study to assess operative versus nonoperative ASLS treatment. Patients were 40–80 years of age and had ASLS (Cobb angle ≥ 30° and Oswestry Disability Index [ODI] ≥ 20 or Scoliosis Research Society [SRS]–22 subscore ≤ 4.0 in the Pain, Function, and/or Self-Image domains). Patients receiving operative and nonoperative treatment were compared using as-treated analysis, and the impact of related SAEs was assessed. Primary outcome measures were ODI and SRS-22. RESULTS The 286 patients with ASLS (107 with nonoperative treatment, 179 with operative treatment) had 2-year and 5-year follow-up rates of 90% (n = 256) and 74% (n = 211), respectively. At 5 years, compared with patients treated nonoperatively, those who underwent surgery had greater improvement in ODI (mean difference −15.2 [95% CI −18.7 to −11.7]) and SRS-22 subscore (mean difference 0.63 [95% CI 0.48–0.78]) (p < 0.001), with treatment effects (TEs) exceeding the minimum detectable measurement difference (MDMD) for ODI (7) and SRS-22 subscore (0.4). TEs at 5 years remained as favorable as 2-year TEs (ODI −13.9, SRS-22 0.52). For patients in the operative group, the incidence rates of treatment-related SAEs during the first 2 years and 2–5 years after surgery were 22.38 and 8.17 per 100 person-years, respectively. At 5 years, patients in the operative group who had 1 treatment-related SAE still had significantly greater improvement, with TEs (ODI −12.2, SRS-22 0.53; p < 0.001) exceeding the MDMD. Twelve patients who received surgery and who had 2 or more treatment-related SAEs had greater improvement than nonsurgically treated patients based on ODI (TE −8.34, p = 0.017) and SRS-22 (TE 0.32, p = 0.029), but the SRS-22 TE did not exceed the MDMD. CONCLUSIONS The significantly greater improvement of operative versus nonoperative treatment for ASLS at 2 years was durably maintained at the 5-year follow-up. Patients in the operative cohort with a treatment-related SAE still had greater improvement than patients in the nonoperative cohort. These findings have important implications for patient counseling and future cost-effectiveness assessments.

Study Design: Retrospective observational cohort. Objectives: We sought to evaluate the impact of ESR on in-hospital and 90-day postoperative opioid consumption, length of stay, urinary catheter removal and postoperative ambulation after lumbar fusion for degenerative conditions. Methods: We evaluated patients undergoing lumbar fusion surgery at a single, multi-surgeon center in the transition period prior to (N = 174) and after (N = 116) adoption of ESR, comparing in-hospital and 90-day postoperative opioid consumption. Regression analysis was used to control for confounders. Secondary analysis was preformed to evaluate the association between ESR and length of stay, urinary catheter removal and ambulation after surgery. Results: Mean age study participants was 52.6 years with 62 (47%) females. Demographic characteristics were similar between the Pre-ESR and ESR groups. ESR patients had better 3-month pain scores, ambulated earlier, had urinary catheters removed earlier and decreased in-hospital opioid consumption compared to Pre-ESR patients. There was no difference in 90-day opioid consumption between the 2 groups. Regression analysis showed that ESR was strongly associated with in-hospital opioid consumption, accounting for 30% of the variability in Morphine Milligram Equivalents (MME). In-hospital opioid consumption was also associated with preoperative pain scores, number of surgical levels, and insurance type (private vs government). Pre-op pain sores were associated with 90-day opioid consumption. Secondary analysis showed that ESR was associated with a shorter length of stay and earlier ambulation. Conclusions: This study showed ESR has the potential to improve recovery after lumbar fusion for degenerative conditions with reduced in-hospital opioid consumption and improved postoperative pain scores.

Controversy exists regarding the ability of posterior (transforaminal) lumbar interbody fusion (PLIF/TLIF) to achieve lordosis. We hypothesized that an interbody device (IBD) designed for positioning in the anterior disc space produces greater lordosis than IBDs designed for straight-in positioning. The purpose of this study is to determine if using either an anterior-position or straight-in position IBD design were associated with successful achievement of postoperative lordosis.A consecutive series of patients undergoing a undergoing a single-level, posterior open midline (transforaminal) lumbar interbody fusion procedure for degenerative spine conditions during a time period when the two types of interbody devices were being used at surgeon discretion were identified from a multi-surgeon academic training center. Patient demographics and radiographic measures including surgical level lordosis (SLL), anterior disc height, middle disc height, posterior disc height, IBD height, and IBD insertion depth were measured on preop, immediate postop, and one-year postop standing radiographs using PACS. Group comparison and regression analysis were performed using SPSS.Sixty-one patients were included (n=37 anterior, n=34 straight-in). Mean age was 59.8±8.7 years, 32 (52%) were female. There was no difference between IBD type (anterior vs. straight-in) for mean Pre-op SLL (19±7° vs. 20±6°, p=0.7), Post-op SLL (21±5° vs 21±6°, p=0.5), or Change in SLL (2±4° vs. 1±5°, p=0.2). Regression analysis showed that Pre-op SLL was the only variable associated with Change in SLL (Beta = negative 0.48, p=0.000). While the mean Change in SLL could be considered clinically insignificant, there was wide variability: from a loss of 9° to a gain of 13°. Gain of lordosis5° only occurred when Pre-op SLL was21°, and loss of lordosis5° only occurred when Pre-op SLL was21°.While group averages showed an insignificant change in segmental lordosis following a posterior (transforaminal) interbody fusion regardless of interbody device type, pre-operative lordosis was correlated with a clinically significant change in segmental lordosis. Preoperative hypolordotic discs were more likely to gain significant lordosis, while preoperative hyperlordotic discs were more likely to lose significant lordosis. Surgeon awareness of this tendency can help guide surgical planning and technique.

Retrospective chart review. To determine if the addition of an anterior lumbar interbody fusion (ALIF) improves the fractional curve in adult spinal deformity correction when compared to posterior surgery alone. ALIF is commonly advocated to improve lordosis and fusion in adult deformity surgery. Improved fractional curve correction may help level the pelvis and minimize proximal malalignment. Patients undergoing thoracolumbar fusion to the pelvis with S2AI screws for deformity were identified and stratified into patients who had an ALIF as part of their deformity correction procedure (ALIF + PSF), and those who had a posterior approach alone. The posterior approach (PSF) includes patients who had a posterolateral fusion with or without a transforaminal lumbar interbody fusion (TLIF). Radiographic parameters measured included pre-op and post-op fractional coronal curve Cobb angle, lumbar lordosis, pelvic tilt, pelvic incidence and sacral slope, major Cobb angle, coronal and sagittal SVA. There were 31 cases in the ALIF + PSF group and 28 in the PSF group. Baseline demographic characteristics of the two groups were similar. Mean pre-op fractional coronal Cobb (18.3° vs 13.4°, p = 0.027) was larger in the ALIF + PSF group, whereas lumbar lordosis (31.0° vs 33.6°, p = 0.487) and pelvic parameters were similar between the two groups. Post-op lumbar lordosis was similar (48.2° vs 43.0°, p = 0.092). Greater fractional coronal curve correction was achieved in the ALIF + PSF group (67%) compared to the PSF group (36%) with a smaller post-op fractional coronal curve in the ALIF + PSF group (6.1°) compared to the PSF group (8.6°, p = 0.053). There is a greater correction of the fractional curve in the ALIF + PSF group compared with the PSF group. While this may not be the primary indication for ALIF, it is a benefit which may facilitate overall deformity correction and leveling of the pelvis.

Hyperkyphosis, including Scheuermann and postural kyphosis, is associated with decreased perceived cosmesis and well being. No patient reported outcome questionnaire specific to kyphosis exists. We sought to assess the internal consistency, test–retest reliability and concurrent validity of a new Kyphosis-specific Spinal Appearance Questionnaire (K-SAQ). A K-SAQ was developed from a modified SAQ to measure kyphosis-specific aspects of appearance. Patients with hyperkyphosis (ages 10–20 years) curves ≥ 50° completed the K-SAQ and SRS-22R at baseline and the K-SAQ 2 weeks later. 55 patients completed the K-SAQ and SRS-22R. 28 patients completed the K-SAQ 2 weeks later. The K-SAQ total averages showed excellent internal consistency (Cronbach’s α = 0.91) and test–retest reliability (ICC = 0.84). Moderate associations were seen between the SRS-22R subtotal average score and K-SAQ total average score and (r = − 0.62, p

OBJECTIVELumbar fusion can lead to significant improvements in patient-reported outcomes (PROs) in patients with degenerative conditions. It is unknown whether the presence of hip or knee arthritis confounds the responses of patients to low-back–specific PROs. This study examined PROs with lumbar fusion in patients with concomitant lower-extremity arthritis. The purpose of the current study was to examine whether patients with significant lower-extremity arthritis who undergo lumbar fusion achieve similar improvements in low-back–specific PROs compared to patients without lower-extremity arthritis.METHODSPatients were identified from a prospectively enrolled multicenter registry of patients undergoing lumbar fusion surgery for degenerative conditions. Two hundred thirty patients identified with lumbar fusion and who also had concomitant lower-extremity arthritis were propensity matched to 233 patients who did not have lower-extremity arthritis based on age, BMI, sex, smoking status, American Society of Anesthesiologists grade, number of levels fused, and surgical approach. One-year improvement in PROs, numeric rating scales (0–10) for back and leg pain, and the Oswestry Disability Index and EuroQol-5D scores were compared for patients with and without lower-extremity arthritis.RESULTSBaseline demographics and preoperative outcome measures did not differ between the two propensity-matched groups with 110 cases each. Patients with concomitant lower-extremity arthritis achieved similar improvement in health-related quality-of-life measures to patients without lower-extremity arthritis, with no significant differences between the groups (p > 0.10).CONCLUSIONSThe presence of lower-extremity arthritis does not adversely affect the results of lumbar fusion in properly selected patients. Patients with lower-extremity arthritis who undergo lumbar fusion can achieve meaningful improvement in PROs similar to patients without arthritis.

BACKGROUND: The opioid epidemic is at epic proportions currently in the United States. Exposure to opioids for surgery and subsequent postoperative pain management is a known risk factor for opioid dependence. In addition, opioids can have a negative impact on multiple aspects including clinical outcomes, length of hospital stay, and overall cost of care. Thus, the greatest effort to reduce perioperative opioid use is necessary and a multimodal pain control (MMPC) has been gaining popularity. However, its efficacy in spine surgery is not well known. We aimed to evaluate the efficacy of a MMPC protocol in patients undergoing lumbar single-level anterior lumbar interbody fusion (ALIF). METHODS: This is a retrospective comparative study. From a prospective, single-surgeon, surgical database, consecutive patients undergoing single-level ALIF with or without subsequent posterior fusion for degenerative lumbar conditions were identified before and after initiation of the MMPC protocol. The MMPC protocol consisted of a preoperative oral regimen of cyclobenzaprine (10 mg), gabapentin (600 mg), acetaminophen (1 g), and methadone (10 mg). Postoperatively they received a bilateral transverse abdominis plane block with 0.5% Ropivacaine prior to extubation. We compared in-hospital opioid consumption between the MMPC and non-MMPC cohorts as well as baseline demographic, the length of hospital stay, cost, and rate of postoperative ileus. Opioid consumption was calculated and normalized to the morphine milligram equivalents (MMEs). RESULTS: In total, 68 patients in the MMPC cohort and 39 in the non-MMPC cohort were identified. There was no difference in baseline demographics including sex, body mass index, smoking status, or preoperative opioid use between the two groups. Although there was no difference in the MMEs on the day of surgery (58.5 vs. 66.9, P=0.387), cumulative MMEs each day after surgery was significantly lower in the MMPC cohort, with final cumulative MMEs being reduced by 62% (120.2 vs. 314.8, P

OBJECTIVEUnexpected nonhome discharge causes additional costs in the current reimbursement models, especially to the payor. Nonhome discharge is also related to longer length of hospital stay and therefore higher healthcare costs to society. With increasing demand for spine surgery, it is important to minimize costs by streamlining discharges and reducing length of hospital stay. Identifying factors associated with nonhome discharge can be useful for early intervention for discharge planning. The authors aimed to identify the drivers of nonhome discharge in patients undergoing 1- or 2-level instrumented lumbar fusion.METHODSThe electronic medical records from a single-center hospital administrative database were analyzed for consecutive patients who underwent 1- to 2-level instrumented lumbar fusion for degenerative lumbar conditions during the period from 2016 to 2018. Discharge disposition was determined as home or nonhome. A logistic regression analysis was used to determine associations between nonhome discharge and age, sex, body mass index (BMI), race, American Society of Anesthesiologists grade, smoking status, marital status, insurance type, residence in an underserved zip code, and operative factors.RESULTSA total of 1502 patients were included. The majority (81%) were discharged home. Factors associated with a nonhome discharge were older age, higher BMI, living in an underserved zip code, not being married, being on government insurance, and having more levels fused. Patients discharged to a nonhome facility had longer lengths of hospital stay (5.6 vs 3.0 days, p < 0.001) and significantly increased hospital costs ($21,204 vs $17,518, p < 0.001).CONCLUSIONSIncreased age, greater BMI, residence in an underserved zip code, not being married, and government insurance are drivers for discharge to a nonhome facility after a 1- to 2-level instrumented lumbar fusion. Early identification and intervention for these patients, even before admission, may decrease the length of hospital stay and medical costs.

Study Design: Retrospective/prospective study. Objective: Models based on preoperative factors can predict patients’ outcome at 1-year follow-up. This study measures the performance of several machine learning (ML) models and compares the results with conventional methods. Methods: Inclusion criteria were patients who had lumbar disc herniation (LDH) surgery, identified in the Danish national registry for spine surgery. Initial training of models included 16 independent variables, including demographics and presurgical patient-reported measures. Patients were grouped by reaching minimal clinically important difference or not for EuroQol, Oswestry Disability Index, Visual Analog Scale (VAS) Leg, and VAS Back and by their ability to return to work at 1 year follow-up. Data were randomly split into training, validation, and test sets by 50%/35%/15%. Deep learning, decision trees, random forest, boosted trees, and support vector machines model were trained, and for comparison, multivariate adaptive regression splines (MARS) and logistic regression models were used. Model fit was evaluated by inspecting area under the curve curves and performance during validation. Results: Seven models were arrived at. Classification errors were within ±1% to 4% SD across validation folds. ML did not yield superior performance compared with conventional models. MARS and deep learning performed consistently well. Discrepancy was greatest among VAS Leg models. Conclusions: Five predictive ML and 2 conventional models were developed, predicting improvement for LDH patients at the 1-year follow-up. We demonstrate that it is possible to build an ensemble of models with little effort as a starting point for further model optimization and selection.

OBJECTIVEMedical comorbidities, particularly preoperatively diagnosed anxiety, depression, and obesity, may influence how patients perceive and measure clinical benefit after a surgical intervention. The current study was performed to define and compare the minimum clinically important difference (MCID) thresholds in patients with and without preoperative diagnoses of anxiety or depression and obesity who underwent spinal fusion for grade 1 degenerative spondylolisthesis.METHODSThe Quality Outcomes Database (QOD) was queried for patients who underwent lumbar fusion for grade 1 degenerative spondylolisthesis during the period from January 2014 to August 2017. Collected patient-reported outcomes (PROs) included the Oswestry Disability Index (ODI), health status (EQ-5D), and numeric rating scale (NRS) scores for back pain (NRS-BP) and leg pain (NRS-LP). Both anchor-based and distribution-based methods for MCID calculation were employed.RESULTSOf 462 patients included in the prospective registry who underwent a decompression and fusion procedure, 356 patients (77.1%) had complete baseline and 12-month PRO data and were included in the study. The MCID values for ODI scores did not significantly differ in patients with and those without a preoperative diagnosis of obesity (20.58 and 20.69, respectively). In addition, the MCID values for ODI scores did not differ in patients with and without a preoperative diagnosis of anxiety or depression (24.72 and 22.56, respectively). Similarly, the threshold MCID values for NRS-BP, NRS-LP, and EQ-5D scores were not statistically different between all groups. Based on both anchor-based and distribution-based methods for determination of MCID thresholds, there were no statistically significant differences between all cohorts.CONCLUSIONSMCID thresholds were similar for ODI, EQ-5D, NRS-BP, and NRS-LP in patients with and without preoperative diagnoses of anxiety or depression and obesity undergoing spinal fusion for grade 1 degenerative spondylolisthesis. Preoperative clinical and shared decision-making may be improved by understanding that preoperative medical comorbidities may not affect the way patients experience and assess important clinical changes postoperatively.

OBJECTIVEPatients with lumbar disc herniation (LDH) typically present with lower-extremity radiculopathy. However, there are patients who have concomitant substantial back pain (BP) and are considered candidates for fusion. The purpose of this study was to determine if patients with LDH and substantial BP improve with discectomy alone.METHODSThe DaneSpine database was used to identify 2399 patients with LDH and baseline BP visual analog scale (VAS) scores ≥ 50 who underwent a lumbar discectomy at one of 3 facilities between June 2010 and December 2017. Standard demographic and surgical variables and patient-reported outcomes, including BP and leg pain (LP) VAS scores (0–100), Oswestry Disability Index (ODI), and European Quality of Life–5 Dimensions Questionnaire (EQ-5D) at baseline and 12 months postoperatively, were collected.RESULTSA total of 1654 patients (69%) had 12-month data available, with a mean age of 48.7 years; 816 (49%) were male and the mean BMI was 27 kg/m2. At 12 months postoperatively, there were statistically significant improvements (p < 0.0001) in BP (72.6 to 36.9), LP (74.8 to 32.6), ODI (50.9 to 25.1), and EQ-5D (0.25 to 0.65) scores.CONCLUSIONSPatients with LDH and LP and concomitant substantial BP can be counseled to expect improvement in their BP 12 months after surgery after a discectomy alone, as well as improvement in their LP.

Study Design Randomized controlled trial with minimum of 5-years follow-up. Objective The purpose of this study is to evaluate the peri- and postoperative complications rates, ectopic bone migration, and reoperation rates, and secondly evaluate the 5-year patient reported outcomes (PROs), in patients treated with decompression and non-instrumented posterolateral fusion with ABM/P-15 or allograft. Methods Patients with degenerative spondylolisthesis were enrolled in a Randomized Clinical Trial and randomized 1:1 to either ABM/P-15 or allograft bone. Patient Reported Outcomes were collected at 5-year follow-up, and patients were invited to a clinical follow-up including a computed tomography scan (CT) to evaluate signs of osteolysis, ectopic bone formation, and bone migration. Results Of 101 subjects enrolled in the primary study, 83 patients were available for the 5-year follow-up. We found a statistically significant difference in back pain and Oswestry Disability Index between groups. Fifty-eight patients agreed to participate in the CT study. Sixty percentage in the ABM/P-15 group vs 30% in the allograft group was classified as fused ( P = .037). There were no differences in complications, reoperation-, or infection rates between the 2 groups. We found 2 patients with migration of graft material. Both patients were asymptomatic at minimum 5-year follow-up. Conclusion Our study indicated that complication rates are no higher in patients treated with ABM/P-15 than allograft. We found significantly higher fusion rates in the AMB/P-15 group than in the allograft group, and patients in the ABM/P-15 group reported less back pain and lower disability score at 5-year follow-up.

A retrospective cohort study.To assess whether patient outcomes and cost-effectiveness of adult spinal deformity (ASD) surgery have improved over the past decade.Surgery for ASD is an effective intervention, but one that is also associated with large initial healthcare expenditures. Changes in the cost profile for ASD surgery over the last decade has not been evaluated previously.ASD patients who received surgery between 2008 and 2019 were included. Analysis of covariance was used to establish estimated marginal means for outcome measures [complication rates, reoperations, health-related quality of life, total cost, utility gained, quality adjusted life years (QALYs), cost-efficiency (cost per QALY)] by year of initial surgery. Cost was calculated using the PearlDiver database and represented national averages of Medicare reimbursement for services within a 30-day window including length of stay and death differentiated by complication/comorbidity, revision, and surgical approach. Internal cost data was based on individual patient diagnosis-related group codes, limiting revisions to those within two years (2Y) of the initial surgery. Cost per QALY over the course of 2008-2019 were then calculated.There were 1236 patients included. There was an overall decrease in rates of any complication (0.78 vs . 0.61), any reoperation (0.25 vs . 0.10), and minor complication (0.54 vs . 0.37) between 2009 and 2018 (all P0.05). National average 2Y cost decreased at an annual rate of $3194 ( R2 =0.6602), 2Y utility gained increased at an annual rate of 0.0041 ( R2 =0.57), 2Y QALYs gained increased annually by 0.008 ( R2 =0.57), and 2Y cost per QALY decreased per year by $39,953 ( R2 =0.6778).Between 2008 and 2019, rates of complications have decreased concurrently with improvements in patient reported outcomes, resulting in improved cost effectiveness according to national Medicare average and individual patient cost data. The value of ASD surgery has improved substantially over the course of the last decade.

Background The Global Alignment and Proportion (GAP) score, based on pelvic incidence-based proportional parameters, was recently developed to predict mechanical complications after surgery for spinal deformities in adults. However, this score has not been validated in an independent external dataset. Questions/purposes After adult spinal deformity surgery, is a higher GAP score associated with (1) an increased risk of mechanical complications, defined as rod fractures, implant-related complications, proximal or distal junctional kyphosis or failure; (2) a higher likelihood of undergoing revision surgery to treat a mechanical complication; and (3) is a lower (more proportioned) GAP score category associated with better validated outcomes scores using the Oswestry Disability Index (ODI), Scoliosis Research Society-22 (SRS-22) and the Short Form-36 questionnaires? Methods A total of 272 patients who had undergone corrective surgeries for complex spinal deformities were enrolled in the Scoli-RISK-1 prospective trial. Patients were included in this secondary analysis if they fulfilled the original inclusion criteria by Yilgor et al. From the original 272 patients, 14% (39) did not satisfy the radiographic inclusion criteria, the GAP score could not be calculated in 14% (37), and 24% (64) did not have radiographic assessment at postoperative 2 years, leaving 59% (159) for analysis in this review of data from the original trial. The GAP score was calculated using parameters from early postoperative radiographs (between 3 and 12 weeks) including pelvic incidence, sacral slope, lumbar lordosis, lower arc lordosis and global tilt, which were independently obtained from a computer software based on centralized patient radiographs. The GAP score was categorized as proportional (scores of 0 to 2), moderately disproportional (scores of 3 to 6), or severely disproportional (scores higher than 7 to 13). Receiver operating characteristic area under curve (AUC) was used to assess associations between GAP score and risk of mechanical complications and risk of revision surgery. An AUC of 0.5 to 0.7 was classified as "no or low associative power", 0.7 to 0.9 as "moderate" and greater than 0.9 as "high". We analyzed differences in validated outcome scores between the GAP categories using Wilcoxon rank sum test. Results A total of 159 patients were included in this study, with a mean age of 58 ± 14 years at the time of surgery. Most patients were female (72%, 115 of 159), the mean number of levels involved in surgery was 12 ± 4, and three-column osteotomy was performed in 76% (120 of 159) of patients. At a minimum of 2 years' follow-up, a higher GAP score was not associated with increased risks of mechanical complications (AUC = 0.60 [95% CI 0.50 to 0.70]). A higher GAP score was not associated with a higher likelihood of undergoing a revision surgery to treat a mechanical complication (AUC = 0.66 [95% 0.53 to 0.78]). However, a moderately disproportioned GAP score category was associated with better SF-36 physical component summary score (36 ± 10 versus 40 ± 11; p = 0.047), better SF-36 mental component summary score (46 ± 13 versus 51 ± 12; p = 0.01), better SRS-22 total score (3.4 ± 0.8 versus 3.7 ± 0.7, p = 0.02) and better ODI score (35 ± 21 versus 25 ± 20; p = 0.003) than severely disproportioned GAP score category. Conclusions Based on the findings of this external validation study, we found that alignment targets based on the GAP score alone were not associated with increased risks of mechanical complications and mechanical revisions in patients with complex adult spinal disorders. Parameters not included in the original GAP score needed to be considered to reduce the likelihood of mechanical complications. Level of evidence Level III, diagnostic study.

Adult spinal deformity (ASD) is a diagnosis that encompasses heterogeneous disorders with an increasing prevalence. This increasing prevalence may be due to greater patient longevity or greater awareness of available treatments. Outcome assessment in ASD has evolved over the last 3 decades from physician-based assessments to a patient-centered perception of improvement. Outcome assessment that is reliable, accurate and responsive to change is especially important in ASD, as surgical treatment is known to carry a high cost and complication rate Glassman (Spine Deform 3:199–203, 2015); Glassman (Spine (Phila Pa 1976) 32: 2764–2770, 2007); Smith (J Neurosurg Spine 25:1–14, 2016). In an era of value-based care, diagnosis associated with such heterogeneity and high cost must provide sound evidence to support the cost versus outcome ratio. Numerous general health and disease specific patient-reported outcome measures (PROMs) have been utilized in ASD. We discuss these instruments in detail in the following state-of-the-art review.

STUDY DESIGN Prospective longitudinal cohort. OBJECTIVES The aim of this study was to determine whether functional treadmill testing (FTT) demonstrates differences between patients treated operatively and nonoperatively for adult symptomatic lumbar scoliosis (ASLS). SUMMARY OF BACKGROUND DATA ASLS has become increasingly prevalent as the population ages. ASLS can be accompanied by neurogenic claudication, leading to difficulty walking. FTT may provide a functional tool to evaluate patients with ASLS. METHODS One hundred and eighty-seven patients who underwent nonoperative (n = 88) or operative treatment (n = 99) of ASLS with complete baseline and 2-year post-treatment FTTs and concurrent patient-reported outcomes were identified. FTT parameters included maximum speed, time to onset of symptoms, distance ambulated, time ambulated, and Back and Leg pain severity before and after testing. RESULTS At baseline, patients treated operatively reported worse post-FTT back pain (4.39 vs. 3.45, P = 0.032) than those treated nonoperatively, despite similar ODI, SRS-22 Pain and Activity domain scores. Mean time ambulated (+2.15 vs. -1.20 P = 0.001), pre-FTT back pain (+0.19 vs. -1.60, P

STUDY DESIGN: A registry-based comparative cohort study with 2-year follow-up.OBJECTIVE: To assess whether Modic changes (MCs) are associated with health-related quality of life, long-term physical disability, back- or leg pain after discectomy.SUMMARY OF BACKGROUND DATA: Previous studies have failed to show a clinically significant association between MCs and patient-reported outcomes (PROs) after discectomy.METHODS: Data from the Danish National Spine Registry on patients undergoing first-time lumbar discectomy at a single institution from 2014 to 2017 with an accessible preoperative lumbar magnetic resonance imaging, complete preoperative, and 2-year follow-up questionnaires were obtained. PROs including Oswestry disability index (ODI), European Quality of Life-Five Dimensions (EQ-5D), visual analogue scale (VAS) back and leg pain, and patient satisfaction were collected. Patients were stratified based on the presence (+MC) or absence (-MC) of MCs on the preoperative MRI.RESULTS: Of 620 patients included, MCs were present in 290 patients (47%). Of these, MC type 1 (MC-1) was present in 73 (25%) and MC type 2 (MC-2) in 217 (75%) patients. Preoperative data for ODI, EQ-5D, VAS-BP, and VAS-LP were comparable for the +MC and -MC groups. Both groups had a statistically significant improvement in PROs from baseline compared with 2-year follow-up (P CONCLUSION: MCs were not found to be associated with health-related quality of life, disability, back- or leg pain, or patient satisfaction 2 years after discectomy.LEVEL OF EVIDENCE: 2.

STUDY DESIGN: Longitudinal Comparative Cohort OBJECTIVE: The purpose of this study is to report on the cost-effectiveness of surgical versus nonsurgical treatment for Adult Symptomatic Lumbar Scoliosis (ASLS) using the as-treated data and provide a comparison to previously reported intent-to-treat (ITT) analysis. SUMMARY OF BACKGROUND DATA: Adult spinal deformity is a relatively prevalent condition for which surgical treatment has become increasingly common but concerns surrounding complications, revision rates and cost-effectiveness remain unresolved. Of these issues, cost-effectiveness is perhaps the most difficult to quantify as the requisite data is difficult to obtain. The purpose of this study is to report on the cost-effectiveness of surgical versus nonsurgical treatment for Adult Symptomatic Lumbar Scoliosis (ASLS) using the as-treated data and provide a comparison to previously reported intent-to-treat (ITT) analysis. METHODS: Patients with at least five-year follow-up data within the same treatment arm were included. Data collected every three months included use of nonoperative modalities, medications and employment status. Costs for surgeries and non-operative modalities were determined using Medicare Allowable rates. Medication costs were determined using the RedBook and indirect costs were calculated based on reported employment status and income. Quality Adjusted Life Years (QALY) was determined using the SF-6D. RESULTS: Of 226 patients, 195 patients (73 Non-op, 122 Op) met inclusion criteria. At five years, 29 (24%) patients in the Op group had a revision surgery of whom two had two revisions and one had three revisions. The cumulative cost for the Op group was $111,451 with a cumulative QALY gain of 2.3. The cumulative cost for the Non-Op group was $29,124 with a cumulative QALY gain of 0.4. This results in an ICER of $44,033 in favor of Op treatment. CONCLUSION: This as-treated cost effectiveness analysis demonstrates that surgical treatment for adult lumbar scoliosis becomes favorable at year-three, one year earlier than suggested by a previous intent-to-treat analysis. LEVEL OF EVIDENCE: II

Study Design: Longitudinal cohort. Objectives: Posterior spinal fusion (PSF) using all-pedicle screw constructs has become the standard procedure in the treatment of adolescent idiopathic scoliosis (AIS). However, there have been several reports that all-pedicle screw constructs or the use of pedicle screws at the upper instrumented vertebrae (UIV) increases the incidence of proximal junctional kyphosis (PJK). We aimed to evaluate the impact of instrumentation type on the incidence of PJK following PSF for AIS. Methods: We performed a stratified random sampling from 3654 patients enrolled in a multicenter database of surgically treated AIS to obtain a representative sample from all Lenke types. Patients were then allocated into 3 groups based on the instrumentation type: all-pedicle screw (PS), hook at UIV with pedicle screws distally (HT), and hybrid constructs (HB). We measured proximal junctional angle (PJA) and defined PJK as PJA ≥ 10° and PJA progression of >10° at the final follow-up. Results: Fifteen (4.3%) of 345 cases had PJK. PJK was significantly more common in PS (11%) compared with HB (1%) and HT (0%) ( P < .001). PJK patients were similar to non-PJK patients regarding age, sex, curve type, UIV, and preoperative coronal Cobb angle. Thoracic kyphosis was significantly higher in the PJK group before surgery. Patients who developed PJK had a statistically significantly larger negative sagittal balance compared with the non-PJK group. Conclusion: The incidence of PJK was 4.3% and was more common in all-pedicle screw constructs. Using hooks at UIV might be a treatment strategy to limit PJK.

OBJECTIVEThe Scoliosis Research Society-22r questionnaire (SRS-22r) has been shown to be reliable, valid, and responsive to change in patients with adult spinal deformity (ASD) undergoing surgery. The minimal clinically important difference (MCID) is the smallest difference in a health-related quality of life score that is considered to be worthwhile or clinically important to the individual. The authors hypothesized that the proportion of patients with ASD achieving an MCID in the SRS-22r score would be different between two culturally different cohorts. The purpose of this study was to compare the proportion of patients with ASD achieving MCID for the SRS-22r domains in North American (NA) and Japanese cohorts.METHODSA total of 137 patients from North America (123 women, mean age 60.0 years) and 60 patients from Japan (56 women, mean age 65.5 years) with at least 2 years of follow-up after corrective spine surgery for ASD were included. Except for self-image, published Japanese MCID values of SRS-22r for ASD were higher (function = 0.90, pain = 0.85, self-image = 1.05, subtotal = 1.05) than the published NA MCID values (function = 0.60, pain = 0.40, self-image = 1.23, subtotal = 0.43).RESULTSThere was a statistically significant improvement in all SRS-22r domain scores at 2 years compared to baseline in both cohorts. Except for mental health (NA = 0.32, Japanese = 0.72, p = 0.005), the mean improvement from baseline to 2 years was similar between the NA and Japanese cohorts. The proportion of patients achieving MCID was higher in North America for function (NA = 51%, Japanese = 30%, p = 0.006), pain (NA = 80%, Japanese = 47%, p < 0.001), and subtotal (NA = 72%, Japanese = 35%, p < 0.001), while there was no significant difference for self-image (NA = 53%, Japanese = 58%, p = 0.454).CONCLUSIONSDespite similar improvements in SRS-22r domain scores from baseline to 2 years postoperatively, the proportion of patients reaching SRS-22r MCID for function, pain, and subtotal after ASD surgery was higher in the NA cohort than in the Japanese cohort. This may imply that patients in North America and Japan may value observed changes in clinical status differently.

Study design A retrospective review of prospectively collected data. Objective The objective of this study was to investigate the fusion status of the lumbar spine and lumbosacral junction at 2 years postoperatively after complex adult spinal deformity (ASD) surgery. Summary of background data Achieving fusion is crucial for maintaining optimal alignment in ASD surgery. However, prospective data assessing fusion status using large patient populations are lacking in this patient population. Materials and methods Postoperative radiographs of 162 patients from the Scoli-Risk-1 database, who underwent complex ASD surgery with fusion to the sacrum, were evaluated by 3 independent spine surgeons at 6-week, 6-month, and 2-year follow-up. The fusion rate of the lumbar spine segments at a 2-year follow-up was determined by using previously published radiographic grading criteria. We also assessed the prevalence of instrumentation failures. Results The interrater reliabilities for grading the fusion status were overall fair at each level evaluated (Fleiss κ, 0.337-0.439). Overall, 70.3% (114/162) demonstrated the solid fusion of the entire lumbar spine at a 2-year follow-up. The fusion rates of each segment were L1/L2: 87.0%, L2/L3: 82.0%, L3/L4: 83.9%, L4/L5: 89.5%, and L5/S1: 89.5%. Pedicle screw loosening was the most frequent implant failure throughout the observation period (9.2%, 11.6%, and 11.0% at 6-wk, 6-mo, and 2-y follow-up, respectively). No rod breakage was observed at 6 weeks, increasing to 9.8% at 2-year follow-up. The prevalence of postoperative proximal junctional kyphosis was 5.5% at 6 weeks, showing no difference at 2 years postoperative. Conclusions In this series of complex ASD surgeries often requiring 3-column osteotomies, 70.3% showed solid fusion of the entire lumbar spine, including the lumbosacral junction. The lumbosacral segments showed a relatively high fusion rate at a 2-year follow-up likely due to the frequent use of anterior column support and graft. The prevalence of rod breakage increased as follow-up proceeded to 9.8%, which was most commonly observed at the lumbosacral junction. Level of evidence Level IV.

Study Design: Longitudinal cohort study with 13-year follow-up. Objective: To assess whether long-term disability is associated with baseline degenerative magnetic resonance imaging (MRI) findings in patients with low back pain (LBP). Methods: In 2004-2005, patients aged 18 to 60 years with chronic LBP were enrolled in a randomized controlled trial and lumbar MRI was performed. Patients completed the Roland-Morris Disability Questionnaire (RMDQ) and the LBP Rating Scale, at baseline and 13 years after the MRI. Multivariate regression analysis was performed with 13-year RMDQ as the dependent variable and baseline disc degeneration (DD, Pfirrmann grade), Modic changes (MC), facet joint degeneration (FJD, Fujiwara grade) smoking status, body mass index, and self-reported weekly physical activity at leisure as independent variables. Results: Of 204 patients with baseline MRI, 170 (83%) were available for follow-up. Of these, 88 had Pfirrmann grade >III (52%), 67 had MC (39%) and 139 had Fujiwara grade >2 (82%) on at least 1 lumbar level. Only MC (β = −0.15, P = .031) and weekly physical activity at leisure (β = −0.51, P < .001) were significantly, negatively, associated with 13-year RMDQ-score ( R2 = 0.31). Conclusion: DD and FJD were not associated with long-term disability. Baseline MC and weekly physical activity at leisure were statistically significantly associated with less long-term disability.

OBJECTIVEPosterior fixation with interbody cage placement can be accomplished via numerous techniques. In an attempt to expedite recovery by limiting muscle dissection, midline lumbar interbody fusion (MIDLIF) has been described. More recently, the authors have developed a robot-assisted MIDLIF (RA-MIDLIF) technique. The purpose of this study was to compare the index episode-of-care (iEOC) parameters between patients undergoing traditional open transforaminal lumbar interbody fusion (tTLIF), MIDLIF, and RA-MIDLIF.METHODSA retrospective review of a prospective, multisurgeon surgical database was performed. Consecutive patients undergoing 1- or 2-level tTLIF, MIDLIF, or RA-MIDLIF for degenerative lumbar conditions were identified. Patients in each cohort were propensity matched based on age, sex, smoking status, BMI, diagnosis, American Society of Anesthesiologists (ASA) class, and number of levels fused. Index EOC parameters such as length of stay (LOS), estimated blood loss (EBL), operating room (OR) time, and actual, direct hospital costs for the index surgical visit were analyzed.RESULTSOf 281 and 249 patients undergoing tTLIF and MIDLIF, respectively, 52 cases in each cohort were successfully propensity matched to the authors’ first 55 RA-MIDLIF cases. Consistent with propensity matching, there was no significant difference in age, sex, BMI, diagnosis, ASA class, or levels fused. Spondylolisthesis was the most common indication for surgery in all cohorts. The mean total iEOC was similar across all cohorts. Patients undergoing RA-MIDLIF had a shorter average LOS (1.53 days) than those undergoing either MIDLIF (2.71 days) or tTLIF (3.58 days). Both MIDLIF and RA-MIDLIF were associated with lower EBL and less OR time compared with tTLIF.CONCLUSIONSDespite concerns for additional cost and time while introducing navigation or robotic technology, a propensity-matched comparison of the authors’ first 52 RA-MIDLIF surgeries with tTLIF and MIDLIF showed promising results for reducing OR time, EBL, and LOS without increasing cost.

Economic modeling of data from a multicenter, prospective registry.The aim of this study was to analyze the cost utility of recombinant human bone morphogenetic protein-2 (BMP) in adult spinal deformity (ASD) surgery.ASD surgery is expensive and presents risk of major complications. BMP is frequently used off-label to reduce the risk of pseudarthrosis.Of 522 ASD patients with fusion of five or more spinal levels, 367 (70%) had at least 2-year follow-up. Total direct cost was calculated by adding direct costs of the index surgery and any subsequent reoperations or readmissions. Cumulative quality-adjusted life years (QALYs) gained were calculated from the change in preoperative to final follow-up SF-6D health utility score. A decision-analysis model comparing BMP versus no-BMP was developed with pseudarthrosis as the primary outcome. Costs and benefits were discounted at 3%. Probabilistic sensitivity analysis was performed using mixed first-order and second-order Monte Carlo simulations. One-way sensitivity analyses were performed by varying cost, probability, and QALY estimates (Alpha = 0.05).BMP was used in the index surgery for 267 patients (73%). The mean (±standard deviation) direct cost of BMP for the index surgery was $14,000 ± $6400. Forty patients (11%) underwent revision surgery for symptomatic pseudarthrosis (BMP group, 8.6%; no-BMP group, 17%; P = 0.022). The mean 2-year direct cost was significantly higher for patients with pseudarthrosis ($138,000 ± $17,000) than for patients without pseudarthrosis ($61,000 ± $25,000) (P 0.001). Simulation analysis revealed that BMP was associated with positive incremental utility in 67% of patients and considered favorable at a willingness-to-pay threshold of $150,000/QALY in52% of patients.BMP use was associated with reduction in revisions for symptomatic pseudarthrosis in ASD surgery. Cost-utility analysis suggests that BMP use may be favored in ASD surgery; however, this determination requires further research.2.

Study design Secondary analysis of subjects in the control anterior cervical discectomy and fusion (ACDF) arm of Medtronic Investigational Device Exemption (IDE) trials for cervical disc arthroplasty (CDA). Objectives To compare patient-reported outcomes (PROs) in patients with radiographic nonunion to patients with a solid fusion. Summary of background data The true prevalence of nonunion after ACDF is unknown. Nonunion may be under-reported, as some patients are not symptomatic enough to justify radiographic evaluation. Methods Three hundred forty-five subjects enrolled in the control arm of IDE trials for CDA who had single-level ACDF with allograft and plate with 24 month data formed the study cohort. Using the 24-month postop evaluation, subjects were divided into those who had radiographic fusion and those who did not using strict study criteria. SF-36, NDI, Neck and Arm pain NRS scores were reported at 12, 24, 36, 60, and 84 months postop. For subjects who had secondary surgery failures, the last observations before the secondary surgery were carried forward to future visits for the analysis. Results Forty-four (13%) patients had radiographic nonunion and 301 (87%) were fused at 24 months postop. At 24 months, PROs were similar between the two groups. Seven patients in the Nonunion group (16%) and 10 (3%) in the Fused group had additional surgery at the index level prior to the 24 follow-up (P = 0.003). Over the 84-month follow-up a total of 9 patients in the Nonunion group (21%) and 22 (7%) in the Fused group had additional surgery at the index level (P = 0.009). Conclusion While the radiographic nonunion rate at 24 months was 13%, PROs show that many of the radiographic nonunions were asymptomatic. Although the majority of patients with radiographic nonunion did not undergo additional surgery, the rate of secondary surgeries at the index level was significantly higher in the radiographic nonunion group. Level of evidence 2.

OBJECTIVEThe midline transforaminal lumbar interbody fusion (MIDLIF) using cortical screw fixation is a novel, minimally invasive procedure that may offer enhanced recovery over traditional open transforaminal lumbar interbody fusion (TLIF). Little information is available regarding the comparative cost-effectiveness of the MIDLIF over conventional TLIF. The purpose of this study was to compare cost-effectiveness of minimally invasive MIDLIF with open TLIF.METHODSFrom a prospective, multisurgeon, surgical database, a consecutive series of patients undergoing 1- or 2-level MIDLIF for degenerative lumbar conditions was identified and propensity matched to patients undergoing TLIF based on age, sex, smoking status, BMI, diagnosis, American Society of Anesthesiologists Physical Status Classification System (ASA) class, and levels fused. Direct costs at 1 year were collected, including costs associated with the index surgical visit as well as costs associated with readmission. Improvement in health-related quality of life was measured using EQ-5D and SF-6D.RESULTSOf 214 and 181 patients undergoing MIDLIF and TLIF, respectively, 33 cases in each cohort were successfully propensity matched. Consistent with propensity matching, there was no difference in age, sex, BMI, diagnosis, ASA class, smoking status, or levels fused. Spondylolisthesis was the most common indication for surgery in both cohorts. Variable direct costs at 1 year were $2493 lower in the MIDLIF group than in the open TLIF group (mean $15,867 vs $17,612, p = 0.073). There was no difference in implant (p = 0.193) or biologics (p = 0.145) cost, but blood utilization (p = 0.015), operating room supplies (p < 0.001), hospital room and board (p < 0.001), pharmacy (p = 0.010), laboratory (p = 0.004), and physical therapy (p = 0.009) costs were all significantly lower in the MIDLIF group. Additionally, the mean length of stay was decreased for MIDLIF as well (3.21 vs 4.02 days, p = 0.05). The EQ-5D gain at 1 year was 0.156 for MIDLIF and 0.141 for open TLIF (p = 0.821). The SF-6D gain at 1 year was 0.071 for MIDLIF and 0.057 for open TLIF (p = 0.551).CONCLUSIONSCompared with patients undergoing traditional open TLIF, those undergoing MIDLIF have similar 1-year gains in health-related quality of life, with total direct costs that are $2493 lower. Although the findings were not statistically significant, minimally invasive MIDLIF showed improved cost-effectiveness at 1 year compared with open TLIF.

BACKGROUND CONTEXT: Patients undergoing lumbar discectomy are typically referred for postoperative rehabilitation. However, evidence regarding effectiveness of postoperative rehabilitation to improve surgical outcome and hasten return to work is scarce with conflicting results in the published literature.PURPOSE: This study investigates the effect of postoperative rehabilitation on return to work, duration of sick leave and working ability after surgery for lumbar disc herniation.STUDY DESIGN/SETTING: Single center randomized controlled trial.PATIENT SAMPLE: Patients scheduled for primary discectomy due to lumbar disc herniation were included in the study.OUTCOME MEASURES: Self-reported measures included working ability, work status and job type defined by the International Standard Classification of Occupations. All outcomes including duration of sick leave were obtained from follow-up questionnaires at one and two years after surgery.METHODS: This is a secondary analysis from a randomized controlled trial comparing patients who were referred to rehabilitation at the municipal facility starting 4-6 weeks postoperative (REHAB) and patients sent home after surgery without any planned rehabilitation course (HOME). Linear regression was performed to identify baseline characteristics associated with duration of sick leave.RESULTS: One hundred forty-six patients were included and equally distributed between the groups. Follow-up rate was 78% after one and two years. Both groups had a similar postoperative sick leave period of approximately 9 weeks. After one year 79% had returned to work in the HOME-group versus 74% in the REHAB-group, which was not statistically significant. Working ability improved from baseline to one year in both groups and this improvement was sustained at two-year follow-up. Stepwise linear regression showed that preoperative duration of leg pain and working ability were associated with duration of postoperative sick leave.CONCLUSIONS: Referral for unstandardized municipal rehabilitation does not affect duration of postoperative sick leave, return to work or working ability in patients recovering after surgery for lumbar disc herniation. Duration of preoperative leg pain and preoperative working ability was significantly associated with the duration of postoperative sick leave.