Costs of Surgery in Adult Spinal Deformity: Do Higher Cost Surgeries Lead to Better Outcomes?

STUDY DESIGN: This was a retrospective study. OBJECTIVE: To assess the impact of surgical costs on patient-reported outcomes in adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: With increased focus on delivering cost-effective health care, interventions with high-resource utilization, such as ASD surgery, have received greater scrutiny. MATERIALS AND METHODS: ASD patients aged 18 years and older with BL and 2-year data were included. Surgical costs were calculated using the 2021 average Medicare reimbursement by Current Procedural Terminology code. Costs of complications and reoperations were intentionally excluded. Patients were ranked into tertiles by surgical cost: highest surgical costs (HC) and lowest surgical costs (LC). They were propensity score matched to account for differences in baseline age and deformity. Bivariate logistic regressions assessed odds of achieving outcomes. RESULTS: Four hundred twenty-one patients met inclusion (60.7 yr, 81.8% female, Charlson Comorbidity Index: 1.6, 27.1 kg/m 2 ), 139 LC and 127 HC patients. After propensity score matching, 102 patients remained in each cost group with an average reimbursement of LC: $12,494 versus HC: $29,248. Matched cohorts had similar demographics and baseline health-related quality of life. Matched groups had similar baseline sagittal vertical axis (HC: 59.0 vs. LC: 56.7 mm), pelvic incidence and lumbar lordosis (HC: 13.1 vs. LC: 13.4°), and pelvic tilt (HC: 25.3 vs. LC: 22.4°). Rates of complications were not significantly different between the cost groups. Compared with the LC group, by 2 years, HC patients had higher odds of reaching substantial clinical benefit in Oswestry Disability Index [odds ratio (OR): 2.356 (1.220, 4.551), P =0.011], in Scoliosis Research Society-Total [OR: 2.988 (1.515, 5.895), P =0.002], and in Numerical Rating Scale Back [OR: 2.739 (1.105, 6.788), P =0.030]. Similar findings were appreciated for HC patients in the setting of Schwab deformity outcome criteria. CONCLUSIONS: Although added cost did not guarantee an ideal outcome, HC patients experienced superior patient-reported outcomes compared with LC patients. Although cost efficiency remains an important priority for health policy, isolating cost reduction may compromise outcomes and add to future costs of reintervention, particularly with more severe baseline deformity. LEVEL OF EVIDENCE: 3.

Pedicle Subtraction Osteotomy Versus Multilevel Anterior Lumbar Interbody Fusion and Lateral Lumbar Interbody Fusion in the Treatment of Adult Spinal Deformity: Trends, Outcomes, and Cost.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of this study was to compare the outcomes of pedicle subtraction osteotomy (PSO) with multilevel anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) in posterior long-segment fusion. BACKGROUND: PSO and ALIF/LLIF are 2 techniques used to restore lumbar lordosis and correct sagittal alignment, with each holding its unique advantages and disadvantages. As there are situations where both techniques can be employed, it is important to compare the risks and benefits of both. PATIENTS AND METHODS: Patients aged 18 years or older who underwent PSO or multilevel ALIF/LLIF with posterior fusion of 7-12 levels and pelvic fixation were identified. 1:1 propensity score was used to match PSO and ALIF/LLIF cohorts for age, sex, and relevant comorbidities, including smoking status. Logistic regression was used to compare medical and surgical outcomes. Trends and costs were generated for both groups as well. RESULTS: ALIF/LLIF utilization in posterior long fusion has been steadily increasing since 2010, whereas PSO utilization has significantly dropped since 2017. PSO was associated with an increased risk of durotomy ( P < 0.001) and neurological injury ( P = 0.018). ALIF/LLIF was associated with increased rates of postoperative radiculopathy ( P = 0.005). Patients who underwent PSO had higher rates of pseudarthrosis within 1 and 2 years ( P = 0.015; P = 0.010), 1-year hardware failure ( P = 0.028), and 2-year reinsertion of instrumentation ( P = 0.009). Reoperation rates for both approaches were not statistically different at any time point throughout the 5-year period. In addition, there were no significant differences in both procedural and 90-day postoperative costs. CONCLUSIONS: PSO was associated with higher rates of surgical complications compared with anterior approaches. However, there was no significant difference in overall reoperation rates. Spine surgeons should select the optimal technique for a given patient and the type of lordotic correction required.

Economic burden of nonoperative treatment of adult spinal deformity.

OBJECTIVE: The purpose of this study was to investigate the cost utility of nonoperative treatment for adult spinal deformity (ASD). METHODS: Nonoperatively and operatively treated patients who met database criteria for ASD and in whom complete radiographic and health-related quality of life data at baseline and at 2 years were available were included. A cost analysis was completed on the PearlDiver database assessing the average cost of nonoperative treatment prior to surgical intervention based on previously published treatments (NSAIDs, narcotics, muscle relaxants, epidural steroid injections, physical therapy, and chiropractor). Utility data were calculated using the Oswestry Disability Index (ODI) converted to SF-6D with published conversion methods. Quality-adjusted life years (QALYs) used a 3% discount rate to account for residual decline in life expectancy (78.7 years). Minor and major comorbidities and complications were assessed according to the CMS.gov manual's definitions. Successful nonoperative treatment was defined as a gain in the minimum clinically importance difference (MCID) in both ODI and Scoliosis Research Society (SRS)-pain scores, and failure was defined as a loss in MCID or conversion to operative treatment. Patients with baseline ODI ≤ 20 and continued ODI of ≤ 20 at 2 years were considered nonoperative successful maintenance. The average utilization of nonoperative treatment and cost were applied to the ASD cohort. RESULTS: A total of 824 patients were included (mean age 58.24 years, 81% female, mean body mass index 27.2 kg/m2). Overall, 75.5% of patients were in the operative and 24.5% were in the nonoperative cohort. At baseline patients in the operative cohort were significantly older, had a greater body mass index, increased pelvic tilt, and increased pelvic incidence-lumbar lordosis mismatch (all p < 0.05). With respect to deformity, patients in the operative group had higher rates of severe (i.e., ++) sagittal deformity according to SRS-Schwab modifiers for pelvic tilt, sagittal vertical axis, and pelvic incidence-lumbar lordosis mismatch (p < 0.05). At 2 years, patients in the operative cohort showed significantly increased rates of a gain in MCID for physical component summary of SF-36, ODI, and SRS-activity, SRS-pain, SRS-appearance, and SRS-mental scores. Cost analysis showed the average cost of nonoperative treatment 2 years prior to surgical intervention to be $2041. Overall, at 2 years patients in the nonoperative cohort had again in ODI of 0.36, did not show a gain in QALYs, and nonoperative treatment was determined to be cost-ineffective. However, a subset of patients in this cohort underwent successful maintenance treatment and had a decrease in ODI of 1.1 and a gain in utility of 0.006 at 2 years. If utility gained for this cohort was sustained to full life expectancy, patients' cost per QALY was $18,934 compared to a cost per QALY gained of $70,690.79 for posterior-only and $48,273.49 for combined approach in patients in the operative cohort. CONCLUSIONS: Patients with ASD undergoing operative treatment at baseline had greater sagittal deformity and greater improvement in health-related quality of life postoperatively compared to patients treated nonoperatively. Additionally, patients in the nonoperative cohort overall had an increase in ODI and did not show improvement in utility gained. Patients in the nonoperative cohort who had low disability and sagittal deformity underwent successful maintenance and cost-effective treatment.

The Additional Economic Burden of Frailty in Adult Cervical Deformity Patients Undergoing Surgical Intervention.

SUMMARY OF BACKGROUND DATA: The influence of frailty on economic burden following corrective surgery for the adult cervical deformity (CD) is understudied and may provide valuable insights for preoperative planning. OBJECTIVE: To assess the influence of baseline frailty status on the economic burden of CD surgery. STUDY DESIGN: Retrospective cohort. MATERIALS AND METHODS: CD patients with frailty scores and baseline and two-year Neck Disability Index data were included. Frailty score was categorized patients by modified CD frailty index into not frail (NF) and frail (F). Analysis of covariance was used to estimate marginal means adjusting for age, sex, surgical approach, and baseline sacral slope, T1 slope minus cervical lordosis, C2-C7 angle, C2-C7 sagittal vertical axis. Costs were derived from PearlDiver registry data. Reimbursement consisted of a standardized estimate using regression analysis of Medicare payscales for services within a 30-day window including length of stay and death. This data is representative of the national average Medicare cost differentiated by complication/comorbidity outcome, surgical approach, and revision status. Cost per quality-adjusted life-year (QALY) at two years was calculated for NF and F patients. RESULTS: There were 126 patients included. There were 68 NF patients and 58 classified as F. Frailty groups did not differ by overall complications, instance of distal junctional kyphosis, or reoperations (all P >0.05). These groups had similar rates of radiographic and clinical improvement by two years. NF and F had similar overall cost ($36,731.03 vs. $37,356.75, P =0.793), resulting in equivocal costs per QALYs for both patients at two years ($90,113.79 vs. $80,866.66, P =0.097). CONCLUSION: F and NF patients experienced similar complication rates and upfront costs, with equivocal utility gained, leading to comparative cost-effectiveness with NF patients based on cost per QALYs at two years. Surgical correction for CD is an economical healthcare investment for F patients when accounting for anticipated utility gained and cost-effectiveness following the procedure. LEVEL OF EVIDENCE: III.

A Short-Term Assessment of Lumbar Sagittal Alignment Parameters in Patients Undergoing Anterior Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To determine if intraoperative on-table lumbar lordosis (LL) and segmental lordosis (SL) coincide with perioperative change in lordosis. SUMMARY OF BACKGROUND DATA: Improvements in sagittal alignment are believed to correlate with improvements in clinical outcomes. Thus, it is important to establish whether intraoperative radiographs predict postoperative improvements in LL or SL. MATERIALS AND METHODS: Electronic medical records were reviewed for patients ≥18 years old who underwent single-level and two-level anterior lumbar interbody fusion with posterior instrumentation between 2016 and 2020. LL, SL, and the lordosis distribution index were compared between preoperative, intraoperative, and postoperative radiographs using paired t tests. A linear regression determined the effect of subsidence on SL and LL. RESULTS: A total of 118 patients met inclusion criteria. Of those, 75 patients had one-level fusions and 43 had a two-level fusion. LL significantly increased following on-table positioning [delta (Δ): 5.7°, P <0.001]. However, LL significantly decreased between the intraoperative to postoperative radiographs at two to six weeks (Δ: -3.4°, P =0.001), while no change was identified between the intraoperative and more than three-month postoperative radiographs (Δ: -1.6°, P =0.143). SL was found to significantly increase from the preoperative to intraoperative radiographs (Δ: 10.9°, P <0.001), but it subsequently decreased at the two to six weeks follow up (Δ: -2.7, P <0.001) and at the final follow up (Δ: -4.1, P <0.001). On linear regression, cage subsidence/allograft resorption was predictive of the Δ SL (ß=0.55; 95% confidence interval: 0.16-0.94; P =0.006), but not LL (ß=0.10; 95% confidence interval: -0.44 to 0.65; P =0.708). CONCLUSION: Early postoperative radiographs may not accurately reflect the improvement in LL seen on intraoperative radiographic imaging, but they are predictive of long-term lumbar sagittal alignment. Each millimeter of cage subsidence or allograft resorption reduces SL by 0.55°, but subsidence does not significantly affect LL. LEVELS OF EVIDENCE: 4.

A Patient-specific Approach to Alignment and Proximal Junctional Kyphosis Risk Assessment in Adult Spinal Deformity Surgery: Development and Validation of a Predictive Tool.

STUDY DESIGN: This was a single-institution, retrospective cohort study. OBJECTIVE: We aimed to develop a predictive model for proximal junctional kyphosis (PJK) severity that considers multiple preoperative variables and modifiable surgical alignment. SUMMARY OF BACKGROUND DATA: PJK is a common complication following adult deformity surgery. Current alignment targets account for age and pelvic incidence but not other risk factors. MATERIALS AND METHODS: This is a single-institution, retrospective cohort study of adult deformity patients with a minimum 2-year follow-up undergoing instrumented fusion between 2009 and 2018. A proportional odds regression model was fit to estimate PJK probability and Hart-International Spine Study Group (ISSG) PJK severity score. Predictors included preoperative Charlson Comorbidity Index, vertebral Hounsfield Units near the upper instrumented vertebrae, pelvic incidence, T1-pelvic angle, and postoperative L1-L4 and L4-S1 lordosis. Predictor effects were assessed using adjusted odds ratios and a nomogram constructed for estimating PJK probability. Bootstrap resampling was used for internal validation. RESULTS: Of 145 patients, 47 (32%) developed PJK. The median PJK severity score was 6 (interquartile range, 4-7.5). After adjusting for predictors, Charlson Comorbidity Index, Hounsfield Units, preoperative T1-pelvic angle, and postoperative L1-L4 and L4-S1 lordosis were significantly associated with PJK severity ( P <0.05). After adjusting for potential overfitting, the model showed acceptable discrimination [ C -statistic (area under the curve)=0.75] and accuracy (Brier score=0.10). CONCLUSIONS: We developed a model to predict PJK probability, adjusted for preoperative alignment, comorbidity burden, vertebral bone density, and modifiable postoperative L1-L4 and L4-S1 lordosis. This approach may help surgeons assess the patient-specific risk of developing PJK and provide a framework for future predictive models assessing PJK risk after adult deformity surgery. LEVEL OF EVIDENCE: Level III.

Multicenter assessment of outcomes and complications associated with transforaminal versus anterior lumbar interbody fusion for fractional curve correction.

OBJECTIVE: Few studies have compared fractional curve correction after long fusion between transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) for adult symptomatic thoracolumbar/lumbar scoliosis (ASLS). The objective of this study was to compare fractional correction, health-related quality of life (HRQL), and complications associated with L4-S1 TLIF versus those of ALIF as an operative treatment of ASLS. METHODS: The authors retrospectively analyzed a prospective multicenter adult spinal deformity database. Inclusion required a fractional curve ≥ 10°, a thoracolumbar/lumbar curve ≥ 30°, index TLIF or ALIF performed at L4-5 and/or L5-S1, and a minimum 2-year follow-up. TLIF and ALIF patients were propensity matched according to the number and type of interbody fusion at L4-S1. RESULTS: Of 135 potentially eligible consecutive patients, 106 (78.5%) achieved the minimum 2-year follow-up (mean ± SD age 60.6 ± 9.3 years, 85% women, 44.3% underwent TLIF, and 55.7% underwent ALIF). Index operations had mean ± SD 12.2 ± 3.6 posterior levels, 86.6% of patients underwent iliac fixation, 67.0% underwent TLIF/ALIF at L4-5, and 84.0% underwent TLIF/ALIF at L5-S1. Compared with TLIF patients, ALIF patients had greater cage height (10.9 ± 2.1 mm for TLIF patients vs 14.5 ± 3.0 mm for ALIF patients, p = 0.001) and lordosis (6.3° ± 1.6° for TLIF patients vs 17.0° ± 9.9° for ALIF patients, p = 0.001) and longer operative duration (6.7 ± 1.5 hours for TLIF patients vs 8.9 ± 2.5 hours for ALIF patients, p < 0.001). In all patients, final alignment improved significantly in terms of the fractional curve (20.2° ± 7.0° to 6.9° ± 5.2°), maximum coronal Cobb angle (55.0° ± 14.8° to 23.9° ± 14.3°), C7 sagittal vertical axis (5.1 ± 6.2 cm to 2.3 ± 5.4 cm), pelvic tilt (24.6° ± 8.1° to 22.7° ± 9.5°), and lumbar lordosis (32.3° ± 18.8° to 51.4° ± 14.1°) (all p < 0.05). Matched analysis demonstrated comparable fractional correction (-13.6° ± 6.7° for TLIF patients vs -13.6° ± 8.1° for ALIF patients, p = 0.982). In all patients, final HRQL improved significantly in terms of Oswestry Disability Index (ODI) score (42.4 ± 16.3 to 24.2 ± 19.9), physical component summary (PCS) score of the 36-item Short-Form Health Survey (32.6 ± 9.3 to 41.3 ± 11.7), and Scoliosis Research Society-22r score (2.9 ± 0.6 to 3.7 ± 0.7) (all p < 0.05). Matched analysis demonstrated worse ODI (30.9 ± 21.1 for TLIF patients vs 17.9 ± 17.1 for ALIF patients, p = 0.017) and PCS (38.3 ± 12.0 for TLIF patients vs 45.3 ± 10.1 for ALIF patients, p = 0.020) scores for TLIF patients at the last follow-up (despite no differences in these parameters at baseline). The rates of total complications were similar (76.6% for TLIF patients vs 71.2% for ALIF patients, p = 0.530), but significantly more TLIF patients had rod fracture (28.6% of TLIF patients vs 7.1% of ALIF patients, p = 0.036). Multiple regression analysis demonstrated that a 1-mm increase in L4-5 TLIF cage height led to a 2.2° reduction in L4 coronal tilt (p = 0.011), and a 1° increase in L5-S1 ALIF cage lordosis led to a 0.4° increase in L5-S1 segmental lordosis (p = 0.045). CONCLUSIONS: Operative treatment of ASLS with L4-S1 TLIF versus ALIF demonstrated comparable mean fractional curve correction (66.7% vs 64.8%), despite use of significantly larger, more lordotic ALIF cages. TLIF cage height had a significant impact on leveling L4 coronal tilt, whereas ALIF cage lordosis had a significant impact on restoration of lumbosacral lordosis. The advantages of TLIF may include reduced operative duration and hospitalization; however, associated HRQL was inferior and more rod fractures were detected in the TLIF patients included in this study.

Association of complete uncinate process removal on 2-year assessment of radiologic outcomes: subsidence and sagittal balance in patients receiving one-level anterior cervical discectomy and fusion.

BACKGROUND: Many patients with cervical radiculopathy experience stenosis of the neural foramens due to cumulative osteophyte or uncovertebral joint hypertrophy. For cervical foraminal stenosis, complete uncinate process resection (UPR) is often conducted concurrently with anterior discectomy and fusion (ACDF). The aim of this study was to assess the clinical and radiological outcomes of ACDF with complete UPR versus ACDF without UPR. METHODS: In total, 105 patients who performed one-level ACDF with a cage-and-plate construct between 2011 and 2015 were retrospectively reviewed. Among them, 37 patients had ACDF with complete UPR, and 68 patients had ACDF without UPR. Radiologic outcomes of disc height, C2-C7 lordosis, T1 slope, C2-C7 sagittal vertical axis (SVA), center of the sella turcica-C7 SVA (St-SVA), spino-cranial angle (SCA), and fusion rate were evaluated on plain X-ray at pre-operation, immediately post-operation, and at 2-year follow-up. For statistically matched pairs analysis, ACDF with UPR group (24 patients) and ACDF without UPR (24 patients) were compared. RESULTS: All of the clinical parameters improved at the 2-year follow up (P < 0.0001). Improvement in visual analogue scale (VAS) scores for arm pain was significantly improved in the ACDF with complete UPR group immediately post-operation. All cervical sagittal parameters, including cervical lordosis, segmental angle, disc height, C2-C7 SVA, St-SVA, T1 slope, and SCA, except for preoperative St-SVA, SCA, and disc height of 2 years follow-up, were similar between the ACDF with complete UPR and ACDF without UPR groups. Differences in disc height, C2-C7 SVA, and SCA at 2-year follow up after preoperative examination, however, were statistically significant (p < 0.05). Subsidence occurred in 9 patients (ACDF with complete UPR: 8 cases [33%] versus ACDF without UPR: 1 cases [4%]; p < 0.05). CONCLUSIONS: Cervical sagittal alignment after ACDF with complete UPR is not significantly different from that achieved with ACDF without UPR. However, subsidence appears to occur more often after ACDF with complete UPR than after ACDF without UPR, although with little to no clinical impact. More precise and careful selection of patients is needed when deciding on additional complete UPR.

Assessment of Patient Outcomes and Proximal Junctional Failure Rate of Patients with Adult Spinal Deformity Undergoing Caudal Extension of Previous Spinal Fusion.

OBJECTIVE: This case series examined patients undergoing caudal extension of prior fusion without alteration of the prior upper instrumented vertebra (UIV) to assess patient outcomes and rates of proximal junctional kyphosis (PJK)/proximal junctional failure (PJF). METHODS: Patients eligible for 2-year minimum follow-up undergoing caudal extension of prior fusion with unchanged UIVs were identified. These patients were evaluated for PJK/PJF, and patient reported outcomes were recorded. RESULTS: In total, 40 patients were included. Mean follow-up duration was 2.2 ± 0.3 years. Patients in this cohort had poor preoperative sagittal alignment (pelvic incidence minus lumbar lordosis [PI-LL] 26.7°, T1 pelvic angle [TPA] 29.0°, sagittal vertical axis [SVA] 93.4 mm) and achieved substantial sagittal correction (ΔSVA -62.2 mm, ΔPI-LL -19.8°, ΔTPA -11.1°) after caudal extension surgery. At final follow-up, there was a 0% rate of PJF among patients undergoing caudal extension of previous fusion without creation of a new UIV, but 27.5% of patients experienced PJK. Patients experienced significant improvement in both the Oswestry Disability Index and Scoliosis Research Society-22r total score at 2 years postoperatively (P < 0.05). In total, 7.5% (n = 3) of patients underwent further revision, at an average of 1.1 ± 0.54 years after the surgery with unaltered UIV. All 3 of these patients underwent revision for rod fracture with no revisions for PJK/PJF. CONCLUSIONS: Patients undergoing caudal extension of previous fusions for sagittal alignment correction have high rates of clinical success, low revision surgery rates, and very low rates of PJF. Minimizing repetitive tissue trauma at the UIV may result in decreased PJF risk because the PJF rate in this cohort of patients with unaltered UIV is below historical PJF rates of patients undergoing sagittal balance correction.

Clinical Outcomes, Complications, and Cost-effectiveness in Surgically Treated Adult Spinal Deformity Over 70 Years: A Propensity score-Matched Analysis.

STUDY DESIGN: This is a multicentered retrospective study. SUMMARY OF BACKGROUND DATA: Surgical correction for the adult spinal deformity (ASD) is effective but carries substantial risks for complications. The diverse pathologies of ASD make it difficult to determine the effect of advanced age on outcomes. OBJECTIVE: The objective of this study was to assess how advanced age affects outcomes and cost-effectiveness for corrective surgery for ASD. MATERIALS AND METHODS: We used data from a multicenter database to conduct propensity score-matched comparisons of 50 patients who were surgically treated for ASD when at least 50 years old and were followed for at least 2 years, to clarify whether advanced age is a risk factor for inferior health-related quality of life and cost-effectiveness. Patients were grouped by age, 50-65 years (M group: 59±4 y) or >70 years (O group: 74±3 y), and were propensity score-matched for sex, body mass index, upper and lower instrumented vertebrae, the use of pedicle-subtraction osteotomy, and sagittal alignment. Cost-effectiveness was determined by cost/quality-adjusted life years. RESULTS: Oswestry Disability Index and Scoliosis Research Society-22 (SRS-22) pain and self-image at the 2-year follow-up were significantly inferior in the O group (Oswestry Disability Index: 32±9% vs. 25±13%, P=0.01; SRS-22 pain: 3.5±0.7 vs. 3.9±0.6, P=0.05; SRS-22 self-image: 3.5±0.6 vs. 3.8±0.9, P=0.03). The O group had more complications than the M group (55% vs. 29%). The odds ratios in the O group were 4.0 for postoperative complications (95% confidence interval: 1.1-12.3) and 4.9 for implant-related complications (95% confidence interval: 1.2-21.1). Cost-utility analysis at 2 years after surgery indicated that the surgery was less cost-effective in the O group (cost/quality-adjusted life year: O group: $211,636 vs. M group: 125,887, P=0.01). CONCLUSIONS: Outcomes for corrective surgery for ASD were inferior in geriatric patients compared with middle-aged patients, in whom the extent of spinal deformity and the operation type were adjusted similarly. Special attention is needed when considering surgical treatment for geriatric ASD patients.

Novel radiographic parameters for the assessment of total body sagittal alignment in adult spinal deformity patients.

OBJECTIVE: In this study, the authors' goal was to develop and validate novel radiographic parameters that better describe total body sagittal alignment (TBSA). METHODS: One hundred sixty-six consecutive operative spinal deformity patients were evaluated using full-body stereoradiographic imaging. Seven TBSA parameters were measured and then correlated to 6 commonly used spinopelvic measurements. TBSA measures consisted of 4 distance measures relating the cranial center of mass (CCOM) to the sacrum, hips, knees, and ankles, and 3 angular measures relating the CCOM to the hips, knees, and ankles. Furthermore, each TBSA parameter was correlated to patient-reported outcome (PRO) scores using the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 (SRS-22) instruments. Thirty patients were randomly selected for inter- and intraobserver reliability testing of the TBSA parameters using intraclass correlation coefficients (ICCs). RESULTS: All TBSA radiographic parameters demonstrated strong linear correlation with the currently accepted primary measure of sagittal balance, the C7 sagittal vertical axis (r = 0.55-0.96, p < 0.001). Moreover, 5 of 7 TBSA measures correlated strongly with ODI and SRS-22 total scores (r = 0.42-0.51, p < 0.001). Inter- and intraobserver reliability for all TBSA measures was good to excellent (interrater ICC = 0.70-0.98, intrarater ICC = 0.77-1.0). CONCLUSIONS: In spine deformity patients, novel TBSA radiographic parameters correlated well with PROs and with currently utilized spinal sagittal measurements. Inter- and intrarater reliability was high for these novel parameters. This is the first study to propose a reliable method for measuring head-to-toe global spinal alignment.

Polyetheretherketone Rods in Lumbar Spine Degenerative Disease: Mid-term Results in a Patient Series Involving Radiological and Clinical Assessment.

AIM: To evaluate the satisfaction of patients operated due to degenerative lumbar spinal diseases with dynamic stabilization placing polyetheretherketone (PEEK) rods and to share their radiological and clinical results (mid-term) with visual analogue scale (VAS) and Oswestry disability index (ODI) scores. MATERIAL AND METHODS: The preoperative and postoperative low back pain, leg pain VAS and ODI scores of 172 patients who were operated for degenerative spinal diseases, were evaluated. Preoperative and postoperative lumbar lordosis were compared. The patients included to the study were evaluated postoperatively around the 2nd year with lumbar MRI by means of adjacent segment disease (ASD) and additional problems. RESULTS: A statistically but not radiologically-by means of sagittal profile reconstruction-significant increase in lumbar lordosis angle was achieved. Significant improvement was observed in the comparison of preoperative and postoperative period in the analysis of patients’ preoperative low back pain (p < 0.0001), and decompression-related leg pain VAS scores (p < 0.0001). Significant improvement was also observed in the ODI scores of the patients (p < 0.0001). Among 172 patients with dynamic stabilization, there were 10 patients who underwent reoperation (5.8%). CONCLUSION: Although it is statistically significant, it can be seen that the lumbar lordosis can not be corrected at significant degrees radiographically in the operations performed with the PEEK rod. Dynamic stabilization with PEEK rod is insufficient for sagittal correction, but the mid-term results reached satisfactory reoperation rates clinically outcomes. Rate of ASD is quite low in stabilization with PEEK rod.

Assessment of radiographic and clinical outcomes of an articulating expandable interbody cage in minimally invasive transforaminal lumbar interbody fusion for spondylolisthesis.

OBJECTIVE The inability to significantly improve sagittal parameters has been a limitation of minimally invasive surgery for transforaminal lumbar interbody fusion (MIS TLIF). Traditional cages have a limited capacity to restore lordosis. This study evaluates the use of a crescent-shaped articulating expandable cage (Altera) for MIS TLIF. METHODS This is a retrospective review of 1- and 2-level MIS TLIF. Radiographic outcomes included differences in segmental and lumbar lordosis, disc height, evidence of fusion, and any endplate violations. Clinical outcomes included the numeric rating scale for leg and back pain and the Oswestry Disability Index (ODI) for low-back pain. RESULTS Thirty-nine patients underwent single-level MIS TLIF, and 5 underwent 2-level MIS TLIF. The mean age was 63.1 years, with 64% women. On average, spondylolisthesis was corrected by 4.3 mm (preoperative = 6.69 mm, postoperative = 2.39 mm, p < 0.001), the segmental angle was improved by 4.94° (preoperative = 5.63°, postoperative = 10.58°, p < 0.001), and segmental height increased by 3.1 mm (preoperative = 5.09 mm, postoperative = 8.19 mm, p < 0.001). At 90 days after surgery the authors observed the following: a smaller postoperative sagittal vertical axis was associated with larger changes in back pain at 90 days (r = -0.558, p = 0.013); a larger decrease in spondylolisthesis was associated with greater improvements in ODI and back pain scores (r = -0.425, p = 0.043, and r = -0.43, p = 0.031, respectively); and a larger decrease in pelvic tilt (PT) was associated with greater improvements in back pain (r = -0.548, p = 0.043). For the 1-year PROs, the relationship between the change in PT and changes in ODI and numeric rating scale back pain were significant (r = 0.612, p = 0.009, and r = -0.803, p = 0.001, respectively) with larger decreases in PT associated with larger improvements in ODI and back pain. Overall for this study there was a 96% fusion rate. Fourteen patients were noted to have endplate violation on intraoperative fluoroscopy during placement of the cage. Only 3 of these had progression of their subsidence, with an overall subsidence rate of 6% (3 of 49) visible on postoperative CT. CONCLUSIONS The use of this expandable, articulating, lordotic, or hyperlordotic interbody cage for MIS TLIF provides a significant restoration of segmental height and segmental lordosis, with associated improvements in sagittal balance parameters. Patients treated with this technique had acceptable levels of fusion and significant reductions in pain and disability.

An assessment of the most reliable method to estimate the sagittal alignment of the cervical spine: analysis of a prospective cohort of 138 cases.

OBJECTIVE Although there is increasing recognition of the importance of cervical spinal sagittal balance, there is a lack of consensus as to the optimal method to accurately assess the cervical sagittal alignment. Cervical alignment is important for surgical decision making. Sagittal balance of the cervical spine is generally assessed using one of two methods; namely, measuring the angle between C-2 and C-7, and drawing a line between C-2 and C-7. Here, the best method to assess sagittal alignment of the cervical spine is investigated. METHODS Data from 138 patients enrolled in a randomized controlled trial (Procon) were analyzed. Two investigators independently measured the angle between C-2 and C-7 by using Harrison's posterior tangent method, and also estimated the shape of the sagittal curve by using a modified Toyama method. The mean angles of each quantitative assessment of the sagittal alignment were calculated and the results were compared. The interrater reliability for both methods was estimated using Cronbach's alpha. RESULTS For both methods the interrater reliability was high: for the posterior tangent method it was 0.907 and for the modified Toyama technique it was 0.984. For a lordotic cervical spine, defined by the modified Toyama method, the mean angle (defined by Harrison's posterior tangent method) was 23.4° ± 9.9° (range 0.4°-52.4°), for a kyphotic cervical spine it was -2.2° ± 9.2° (range -16.1° to 16.9°), and for a straight cervical spine it was 10.5° ± 8.2° (range -11° to 36°). CONCLUSIONS An absolute measurement of the angle between C-2 and C-7 does not unequivocally define the sagittal cervical alignment. As can be seen from the minimum and maximum values, even a positive angle between C-2 and C-7 could be present in a kyphotic spine. For this purpose, the modified Toyama method (drawing a line from the posterior inferior part of the vertebral body of C-2 to the posterior upper part of the vertebral body of C-7 without any measurements) is a better tool for a global assessment of cervical sagittal alignment. Clinical trial registration no.: ISRCTN41681847 ( https://www.isrctn.com ).

The Impact of Lumbar Spine Disease and Deformity on Total Hip Arthroplasty Outcomes.

Concomitant spine and hip disease in patients undergoing total hip arthroplasty (THA) presents a management challenge. Degenerative lumbar spine conditions are known to decrease lumbar lordosis and limit lumbar flexion and extension, leading to altered pelvic mechanics and increased demand for hip motion. In this study, the effect of lumbar spine disease on complications after primary THA was assessed. The Medicare database was searched from 2005 to 2012 using International Classification of Diseases, Ninth Revision, procedure codes for primary THA and diagnosis codes for preoperative diagnoses of lumbosacral spondylosis, lumbar disk herniation, acquired spondylolisthesis, and degenerative disk disease. The control group consisted of all patients without a lumbar spine diagnosis who underwent THA. The risk ratios for prosthetic hip dislocation, revision THA, periprosthetic fracture, and infection were significantly higher for all 4 lumbar diseases at all time points relative to controls. The average complication risk ratios at 90 days were 1.59 for lumbosacral spondylosis, 1.62 for disk herniation, 1.65 for spondylolisthesis, and 1.53 for degenerative disk disease. The average complication risk ratios at 2 years were 1.66 for lumbosacral spondylosis, 1.73 for disk herniation, 1.65 for spondylolisthesis, and 1.59 for degenerative disk disease. Prosthetic hip dislocation was the most common complication at 2 years in all 4 spinal disease cohorts, with risk ratios ranging from 1.76 to 2.00. This study shows a significant increase in the risk of complications following THA in patients with lumbar spine disease. [Orthopedics. 2017; 40(3):e520-e525.].

Role of Ethnicity in Alignment Compensation: Propensity Matched Analysis of Differential Compensatory Mechanism Recruitment Patterns for Sagittal Malalignment in 288 ASD Patients From Japan, Korea, and United States.

STUDY DESIGN: Retrospective review of adult spinal deformity patients in a multiethnic database. OBJECTIVE: To investigate the role of ethnicity on recruitment of compensatory mechanisms for sagittal spinal deformity. SUMMARY OF BACKGROUND DATA: While the impacts of age, sex, and pelvic morphology on the ability to compensate for sagittal malalignment have been investigated, the role of ethnicity in compensatory mechanism recruitment is poorly understood. METHODS: Patients from USA (85% Caucasian) >25 y/o were propensity matched by age, sex, and pelvic incidence with patients from Korea and Japan. Only primary patients or those with existing fusion below T12 were retained for analysis. Groups were subclassified by deformity severity (aligned: sagittal vertical axis (SVA) <50 mm; moderate malalignment: SVA 50-100 mm; severe malalignment: SVA >100 mm). Radiographic measurements including pelvic retroversion, thoracic kyphosis, loss of lumbar lordosis (PI minus LL), cervical lordosis, and cervical SVA were compared between the groups. RESULTS: There were 288 patients (96 each in USA, KOR, JPN), with similar age (64-67 yr) and PI (49-53°). USA had smaller pelvic incidence minus lumbar lordosis in every alignment group (P <0.05). In moderate malalignment, JPN had more pelvic retroversion than USA (30° vs. 20°), and KOR had more thoracic hypokyphosis than USA (15 vs. 31°). In severe malalignment, JPN had more pelvic retroversion than USA (39° vs. 27°), and KOR had more thoracic hypokyphosis than USA (15° vs. 31°). KOR had smaller cSVA than USA in both aligned (11 vs. 27 mm) and moderate (19 vs. 31 mm) malalignment. In severe malalignment, KOR had less cervical lordosis (13° KOR vs. 15° USA vs. 27° JPN). All differences with P <0.05. CONCLUSION: Compensation for sagittal is ethnicity dependent. Korean patients favor thoracic compensation via hypokyphosis, and Japanese patients favor pelvic compensation via retroversion. Patient ethnicity should be considered when evaluating the sagittal plane and surgical correction strategies. LEVEL OF EVIDENCE: 3.

[Reckoning: Assessment of 21 years' work in spinal surgery]. / Számvetés: 21 éves gerincsebészeti tevékenység mérlege.

INTRODUCTION: Of the world-wide used Cotrel-Dubousset instrumentation and surgical technique providing breakthrough for the three-dimensional correction and multi-segmental fixation of spinal deformity surgery in Hungary is linked to the author's name, who carried out 1655 spine deformity surgeries in the last 21 years. AIM: The aim of the author was to discuss his own results in the field of spine surgery and compare his own data to those published in the international literature. METHOD: At the beginning hooks, followed by hybrid instrumentation with hooks in thoracic area and transpedicular screws in lumbar spine have been used for the segmental fixation. During the correction process, initially the classic derotation maneuver was used, followed by the translation and then the in situ bending techniques and, finally, a combination of the above three techniques have been applied. RESULTS: In addition to the restoration of normal sagittal balance, an average of 40.8° (SD, 25.9), a 65.5% correction was achieved in the frontal plane, which partly exceeds and partly consistent with the published international results. The incidence of inflammation (3.9%), and mechanical complications (1.7%) was similar to the international average, while the incidence of neurological complications (0.48%) was slightly lower than the average of international data. CONCLUSIONS: The author believes that the better correction results as compared to the international average could be due to the always consistent application of the Cotrel-Dubousset instrumentation correction philosophy based on the meticulous segmental analysis of spine deformities.

Comparison of anterior and posterior vertebral column resection versus anterior release with posterior internal distraction for severe and rigid scoliosis.

PURPOSE: This study aimed to compare efficacy, safety, and cost between staged vertebral column resection (VCR) and anterior release with internal distraction in treating severe and rigid idiopathic scoliosis. METHODS: We examined the records of 43 patients with severe and rigid idiopathic scoliosis treated in our hospital. Group A included 26 patients who underwent anterior VCR followed by posterior vertebral column resection and instrumentation from July 2007 to October 2009. Group B included 17 patients who underwent anterior release with temporary posterior internal distraction, followed by posterior fusion and instrumentation from November 2009 to June 2011. The average preoperative main curve for group A was 101.3° (range 90°-130°) and for group B was 104.8° (range 90°-136°). Minimum follow-up was 2 years. Radiographic and clinical outcomes were compared between the groups. RESULTS: A t test demonstrated that the differences between the groups in preoperative and postoperative coronal and sagittal imbalance, thoracic kyphosis correction, and lumbar lordosis were not statistically significant. Patients in group B showed better postoperative (P = 0.031) and final (P = 0.030) main thoracic curve correction (76.8 and 75.6 %, respectively) than patients in group A (68.3 and 67.7 %, respectively). Patients in group B had better thoracolumbar or lumbar curve correction (85.8 %) than those in group A (76.8 %; P = 0.048). The differences in blood loss and operation time were not statistically significant (P = 0.094 and P = 0.060, respectively). Hospital stay was longer (P = 0.001) and patient cost was higher (P < 0.001) for patients in group B. One patient in group A required ventilator support for 12 h after anterior surgery. One transient dyspnea occurred in group B. No neurologic deficits occurred in either group. CONCLUSION: Anterior release with posterior internal distraction produces better corrective effects than anterior and posterior VCR, though hospital stay and costs are greater.

Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy.

STUDY DESIGN: Narrative review. OBJECTIVE: To provide a comprehensive narrative review of cervical alignment parameters, the methods for quantifying cervical alignment, normal cervical alignment values, and how alignment is associated with cervical deformity and myelopathy with discussions of health-related quality of life. SUMMARY OF BACKGROUND DATA: Indications for surgery to correct cervical alignment are not well-defined and there is no set standard to address the amount of correction to be achieved. In addition, classifications of cervical deformity have yet to be fully established and treatment options defined and clarified. METHODS: A survey of the cervical spine literature was conducted. RESULTS: New normative cervical alignment values from an asymptomatic volunteer population are introduced, updated methods for quantifying cervical alignment are discussed, and describing the relationship between cervical alignment, disability, and myelopathy are outlined. Specifically, methods used to quantify cervical alignment include cervical lordosis, cervical sagittal vertical axis, and horizontal gaze with the chin-brow vertical angle. Updated methods include T1 slope. Evidence from a few recent studies suggests correlations between radiographical parameters in the cervical spine and health-related quality of life. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is emerging and critical. Cervical myelopathy and sagittal alignment of the cervical spine are closely related as cervical deformity can lead to spinal cord compression and tension. CONCLUSION: Cervical deformity correction should take on a comprehensive approach in assessing global cervical-pelvic relationships and the radiographical parameters that effect health-related quality of life scores are not well-defined. Cervical alignment may be important in assessment and treatment of cervical myelopathy. Future work should concentrate on correlation of cervical alignment parameters to disability scores and myelopathy outcomes. SUMMARY STATEMENTS: STATEMENT 1: Cervical sagittal alignment (cervical SVA and kyphosis) is related to thoracolumbar spinal pelvic alignment and to T1 slope. STATEMENT 2: When significant deformity is clinically or radiographically suspected, regional cervical and relative global spinal alignment should be evaluated preoperatively via standing 3-foot scoliosis X-rays for appropriate operative planning. STATEMENT 3: Cervical sagittal alignment (C2-C7 SVA) is correlated to regional disability, general health scores and to myelopathy severity. STATEMENT 4: When performing decompressive surgery for CSM, consideration should be given to correction of cervical kyphosis and cervical sagittal imbalance (C2-C7 SVA) when present.

Alternative grafts in anterior cervical fusion.

OBJECTIVE: The present retrospective study was conducted to compare the clinical and radiographic outcomes in patients undergoing anterior cervical discectomy with fusion (ACDF) using carbon fiber reinforced polymer (CFRP) cages, or allograft. METHODS: We retrospectively reviewed cases of ACDF using allograft in 20 patients, and CFRP in 19 who had sequential radiographs before and after surgery, and at 1 year. RESULTS: There were no apparent significant differences between the 2 groups in age (p=0.057), gender (p=0.635), or complications (p=0.648). At 12 months, there were no cases of construct failure, and fusion appeared to have been achieved in patients of both groups. Lordosis was increased significantly in both groups after surgery (p<0.001 in allograft and p=0.025 in CFRP), and was maintained up until 1 year (p<0.018 in allograft and p=0.05 in CFRP) without a difference between groups (p=0.721). Anterior interbody height was significantly increased (p<0.001 in both groups at each time points) after surgery, without a significant difference between groups (p>0.21). This increase in height was greatest in magnitude immediately after surgery, and declined with the passage of time. There was no detectable health-related quality of life difference between allograft and CFRP group after surgery (p>0.05). CONCLUSION: The present study demonstrates that CFRP cages appear to have comparable fusion rates, restoration of lordosis and disc space height, and complication rates to patients who undergo ACDF with allograft.