The Predictive Potential of Nutritional and Metabolic Burden: Development of a Novel Validated Metric Predicting Increased Postoperative Complications in Adult Spinal Deformity Surgery

STUDY DESIGN

A retrospective cohort review.

OBJECTIVE

To develop a scoring system for predicting increased risk of postoperative complications in adult spinal deformity (ASD) surgery based on baseline nutritional and metabolic factors.

BACKGROUND

Endocrine and metabolic conditions have been shown to adversely influence patient outcomes and may increase the likelihood of postoperative complications. The impact of these conditions has not been effectively evaluated in patients undergoing ASD surgery.

MATERIALS AND METHODS

ASD patients 18 years or above with baseline and two-year data were included. An internally cross-validated weighted equation using preoperative laboratory and comorbidity data correlating to increased perioperative complications was developed via Poisson regression. Body mass index (BMI) categorization (normal, over/underweight, and obese) and diabetes classification (normal, prediabetic, and diabetic) were used per the Centers for Disease Control and Prevention and the American Diabetes Associates parameters. A novel ASD-specific nutritional and metabolic burden score (ASD-NMBS) was calculated via Beta-Sullivan adjustment, and Conditional Inference Tree determined the score threshold for experiencing ≥1 complication. Cohorts were stratified into low-risk and high-risk groups for comparison. Logistic regression assessed correlations between increasing burden score and complications.

RESULTS

Two hundred one ASD patients were included (mean age: 58.60±15.4, sex: 48% female, BMI: 29.95±14.31, Charlson Comorbidity Index: 3.75±2.40). Significant factors were determined to be age (+1/yr), hypertension (+18), peripheral vascular disease (+37), smoking status (+21), anemia (+1), VitD hydroxyl (+1/ng/mL), BMI (+13/cat), and diabetes (+4/cat) (model: P <0.001, area under the curve: 92.9%). Conditional Inference Tree determined scores above 175 correlated with ≥1 post-op complication ( P <0.001). Furthermore, HIGH patients reported higher rates of postoperative cardiac complications ( P =0.045) and were more likely to require reoperation ( P =0.024) compared with low patients.

CONCLUSIONS

The development of a validated novel nutritional and metabolic burden score (ASD-NMBS) demonstrated that patients with higher scores are at greater risk of increased postoperative complications and course. As such, surgeons should consider the reduction of nutritional and metabolic burden preoperatively to enhance outcomes and reduce complications in ASD patients.

The Impact of Peri-operative Enhanced Recovery After Surgery Protocols on Outcomes Following Adult Cervical Deformity Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To assess the impact of Enhanced recovery after surgery (ERAS) protocols on peri-operative course in adult cervical deformity (ACD) corrective surgery.

METHODS

Patients ≥18 yrs with complete pre-(BL) and up to 2-year (2Y) radiographic and clinical outcome data were stratified by enrollment in an ERAS protocol that commenced in 2020. Differences in demographics, clinical outcomes, radiographic alignment targets, peri-operative factors and complication rates were assessed via means comparison analysis. Logistic regression analysed differences while controlling for baseline disability and deformity.

RESULTS

We included 220 patients (average age 58.1 ± 11.9 years, 48% female). 20% were treated using the ERAS protocol (ERAS+). Disability was similar between both groups at baseline. When controlling for baseline disability and myelopathy, ERAS- patients were more likely to utilize opioids than ERAS+ (OR 1.79, 95% CI: 1.45-2.50, P = .016). Peri-operatively, ERAS+ had significantly lower operative time (P < .021), lower EBL (583.48 vs 246.51, P < .001), and required significantly lower doses of propofol intra-operatively than ERAS- patients (P = .020). ERAS+ patients also reported lower mean LOS overall (4.33 vs 5.84, P = .393), and were more likely to be discharged directly to home (χ2(1) = 4.974, P = .028). ERAS+ patients were less likely to require steroids after surgery (P = .045), were less likely to develop neuromuscular complications overall (P = .025), and less likely experience venous complications or be diagnosed with venous disease post-operatively (P = .025).

CONCLUSIONS

Enhanced recovery after surgery programs in ACD surgery demonstrate significant benefit in terms of peri-operative outcomes for patients.

Highest Achievable Outcomes for Adult Spinal Deformity Corrective Surgery: Does Frailty Severity Exert a Ceiling Effect?

STUDY DESIGN

Retrospective Single-Center Study.

OBJECTIVE

To assess the influence of frailty on optimal outcome following ASD corrective surgery.

SUMMARY OF BACKGROUND DATA

Frailty is a determining factor in outcomes after ASD surgery and may exert a ceiling effect on best possible outcome.

METHODS

ASD patients with frailty measures, baseline and 2-year ODI included. Frailty was classified as Not Frail (NF), Frail (F) and Severely Frail (SF) based on the modified Frailty Index, then stratified into quartiles based on 2-year ODI improvement (most improved designated "Highest"). Logistic regression analyzed relationships between frailty and ODI score and improvement, maintenance, or deterioration. A Kaplan-Meier survival curve was used to analyze differences in time to complication or reoperation.

RESULTS

393 ASD patients were isolated (55.2% NF, 31.0% F, and 13.7% SF), then classified as 12.5% NF-Highest, 17.8% F-Highest, and 3.1% SF-Highest. The SF-group had the highest rate of deterioration (16.7%, P=0.025) at the second postoperative year but the groups were similar in improvement (NF: 10.1%, F: 11.5%, SF: 9.3%, P=0.886). Improvement of SF patients was greatest at 6 months (ΔODI of -22.6±18.0, P<0.001) but NF and F patients reached maximal ODI at 2 years (ΔODI of -15.7±17.9 and -20.5±18.4, respectively). SF patients initially showed the greatest improvement in ODI (NF: -4.8±19.0, F: -12.4±19.3, SF: -22.6±18.0 at 6 months, P<0.001). A Kaplan-Meier survival curve showed a trend of less time to major complication or reoperation by 2 years with increasing frailty (NF: 7.5±0.381 years, F: 6.7±0.511 years, SF: 5.8±0.757 years; P=0.113).

CONCLUSIONS

Increasing frailty had a negative effect on maximal improvement, where severely frail patients exhibited a parabolic effect with greater initial improvement due to higher baseline disability, but reached a ceiling effect with less overall maximal improvement. Severe frailty may exert a ceiling effect on improvement and impair maintenance of improvement following surgery.

LEVEL OF EVIDENCE

III.

An Economic Analysis of Early and Late Complications After Adult Spinal Deformity Correction

STUDY DESIGN/SETTING

Retrospective cohort.

OBJECTIVE

Adult spinal deformity (ASD) corrective surgery is often a highly invasive procedure portending patients to both immediate and long-term complications. Therefore, we sought to compare the economic impact of certain complications before and after 2 years.

METHODS

ASD patients with minimum 3-year data included. Complication groups were defined as follows: any complication, major, medical, mechanical, radiographic, and reoperation. Complications stratified by occurrence before or after 2 years postoperatively. Published methods converted ODI to SF-6D to QALYs. Cost was calculated using CMS.gov definitions. Marginalized means for utility gained and cost-per-QALY were calculated via ANCOVA controlling for significant confounders.

RESULTS

244 patients included. Before 2Y, complication rates: 76% ≥1 complication, 18% major, 26% required reoperation. After 2Y, complication rates: 32% ≥1 complication, 4% major, 2.5% required reoperation. Major complications after 2 years had worse cost-utility (.320 vs .441, P = .1). Patients suffering mechanical complications accrued the highest overall cost ($130,482.22), followed by infection and PJF for complications before 2 years. Patients suffering a mechanical complication after 2 years had lower cost-utility ($109,197.71 vs $130,482.22, P = .041). Patients developing PJF after 2 years accrued a better cost-utility ($77,227.84 vs $96,873.57; P = .038), compared to PJF before 2 years.

CONCLUSION

Mechanical complications had the single greatest impact on cost-utility after adult spinal deformity surgery, but less so after 2 years. Understanding the cost-utility of specific interventions at certain timepoints may mitigate economic burden and prophylactic efforts should strategically be made against early mechanical complications.

Can Baseline Disability Predict Outcomes in Adult Spinal Deformity Surgery?

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To assess if there is a threshold of baseline disability beyond which the patient-reported outcomes after surgical correction of adult spinal deformity (ASD) are adversely impacted.

BACKGROUND

Patient-reported outcomes vary after correction of adult spinal deformity, even when patients are optimally realigned. There is a paucity of literature examining the impact of baseline disability on patient-reported outcomes in ASD.

METHODS

Patients with baseline (BL) and two-year data were included. Disability was ranked according to BL Oswestry Disability Index (ODI) into quintiles: Q1 (lowest ODI score) to Q5 (highest ODI score). Adjusted logistic regression analyses evaluated the likelihood of reaching ≥1 MCID in Scoliosis Research Society Outcomes Questionnaire (SRS-22) Pain, SRS-22 Activity, and Short Form-36 physical component summary at two years across disability groups Q1-Q4 with respect to Q5. Sensitivity tests were performed, excluding patients with any "0" Schwab modifiers at BL.

RESULTS

Compared with patients in Q5, the odds of reaching MCID in SRS-22 Pain at 2Y were significantly higher for those in Q1 (OR: 3.771), Q2 (OR: 3.006), and Q3 (OR: 2.897), all P <0.021. Similarly, compared with patients in Q5, the odds of reaching MCID in SRS-22 Activity at two years were significantly higher for those in Q2 (OR: 3.454) and Q3 (OR: 2.801), both P <0.02. Lastly, compared with patients in Q5, odds of reaching MCID in Short Form-36 physical component summary at two years were significantly higher for patients in Q1 (OR: 5.350), Q2 (OR: 4.795), and Q3 (OR: 6.229), all P <0.004.

CONCLUSIONS

This study found that patients presenting with moderate disability at BL (ODI<40) consistently surpassed health-related quality of life outcomes as compared with those presenting with greater levels of disability. We propose that a baseline ODI of 40 represents a disability threshold within which operative inte rvention maximizes patient-reported outcomes. Furthermore, delaying the intervention until patients progress to severe disability may limit the benefits of surgical correction in ASD patients.

LEVEL OF EVIDENCE

3.

Comparison of multilevel low-grade techniques versus three-column osteotomies in adult spinal deformity surgery: does harmonious correction matter?

OBJECTIVE

Recent debate has arisen between whether to use a three-column osteotomy (3CO) or multilevel low-grade (MLG) techniques to treat severe sagittal malalignment in adult spinal deformity (ASD) surgery. The goal of this study was to compare the outcomes of 3CO and MLG techniques performed in corrective surgeries for ASD.

METHODS

ASD patients who had a baseline PI-LL > 30° and 2-year follow-up data were included. Patients underwent either 3CO or MLG (thoracolumbar posterior column osteotomies at ≥ 3 levels or anterior lumbar interbody fusion at ≥ 3 levels with no 3CO). The segmental utility ratio was used to assess relative segmental correction (segmental correction divided by overall correction in lordosis divided by the number of thoracolumbar interventions [interbody fusion, thoracolumbar posterior column osteotomies, and 3CO]). The paired t-test was used to assess lordotic distribution by differences in lordosis between adjacent lumbar disc spaces (e.g., L1-2 to L2-3). Multivariate analysis, controlling for age, sex, BMI, osteoporosis, baseline pelvic incidence, and T1 pelvic angle, was used to evaluate the complication rates and radiographic and patient-reported outcomes between the groups.

RESULTS

A total of 93 patients were included, 53% of whom underwent MLG and 47% of whom underwent 3CO. The MLG group had a lower BMI (p < 0.05). MLG patients received fewer previous fusions than 3CO patients (31% vs 80%, p < 0.001). MLG patients had 24% less blood loss but a 22% longer operative time (565 vs 419 minutes, p = 0.008). Using adjusted analysis, the 3CO group had greater segmental and relative correction at each level (segmental utility ratio mean 69% for 3CO vs 23% for MLG, p < 0.001). However, the 3CO group had lordotic differences between two adjacent lumbar disc pairs (range -0.5° to 9.0°, p = 0.009), while MLG was more harmonious (range 2.2°-6.5°, p > 0.4). MLG patients were more likely to undergo realignment to age-adjusted standards (OR 5.6, 95% CI 1.2-46.4; p = 0.033). MLG patients were less likely to develop neurological complications or undergo reoperation (OR 0.4, 95% CI 0.1-0.9; p = 0.041). Adjusted analysis revealed that MLG patients more often met a substantial clinical benefit in the Oswestry Disability Index score (OR 5.3, 95% CI 1.1-26.8; p = 0.043).

CONCLUSIONS

MLG techniques showed better utility in lumbar distribution and age-adjusted global correction while minimizing neurological complications and reoperation rates by 2 years postoperatively. In selected instances, these techniques may offer the spine deformity surgeon a safer alternative when correcting severe adult spinal deformity.

The Impact of Lumbopelvic Realignment Versus Prevention Strategies at the Upper-instrumented Vertebra on the Rates of Junctional Failure Following Adult Spinal Deformity Surgery

STUDY DESIGN/SETTING

Retrospective.

OBJECTIVE

Evaluate the surgical technique that has the greatest influence on the rate of junctional failure following ASD surgery.

SUMMARY OF BACKGROUND DATA

Differing presentations of adult spinal deformity(ASD) may influence the extent of surgical intervention and the use of prophylaxis at the base or the summit of a fusion construct to influence junctional failure rates.

MATERIALS AND METHODS

ASD patients with two-year(2Y) data and at least 5-level fusion to the pelvis were included. Patients were divided based on UIV: [Longer Construct: T1-T4; Shorter Construct: T8-T12]. Parameters assessed included matching in age-adjusted PI-LL or PT, aligning in GAP-relative pelvic version or Lordosis Distribution Index. After assessing all lumbopelvic radiographic parameters, the combination of realigning the two parameters with the greatest minimizing effect of PJF constituted a good base. Good s was defined as having: (1) prophylaxis at UIV (tethers, hooks, cement), (2) no lordotic change(under-contouring) greater than 10° of the UIV, (3) preoperative UIV inclination angle<30°. Multivariable regression analysis assessed the effects of junction characteristics and radiographic correction individually and collectively on the development of PJK and PJF in differing construct lengths, adjusting for confounders.

RESULTS

In all, 261 patients were included. The cohort had lower odds of PJK(OR: 0.5,[0.2-0.9]; P =0.044) and PJF was less likely (OR: 0.1,[0.0-0.7]; P =0.014) in the presence of a good summit. Normalizing pelvic compensation had the greatest radiographic effect on preventing PJF overall (OR: 0.6,[0.3-1.0]; P =0.044). In shorter constructs, realignment had a greater effect on decreasing the odds of PJF(OR: 0.2,[0.02-0.9]; P =0.036). With longer constructs, a good summit lowered the likelihood of PJK(OR: 0.3,[0.1-0.9]; P =0.027). A good base led to zero occurrences of PJF. In patients with severe frailty/osteoporosis, a good summit lowered the incidence of PJK(OR: 0.4,[0.2-0.9]; P =0.041) and PJF (OR: 0.1,[0.01-0.99]; P =0.049).

CONCLUSION

To mitigate junctional failure, our study demonstrated the utility of individualizing surgical approaches to emphasize an optimal basal construct. Achievement of tailored goals at the cranial end of the surgical construct may be equally important, especially for higher-risk patients with longer fusions.

LEVEL OF EVIDENCE

3.

Outcomes and survival analysis of adult cervical deformity patients with 10-year follow-up

BACKGROUND

Previous studies have demonstrated that adult cervical deformity patients may be at increased risk of death in conjunction with increased frailty or a weakened physiologic state. However, such studies have often been limited by follow-up duration, and longer-term studies are needed to better assess temporal changes in ACD patients and associated mortality risk.

PURPOSE

To assess if patients with decreased comorbidities and physiologic burden will be at lessened risk of death for a greater length of time after undergoing adult cervical deformity surgery.

STUDY DESIGN/SETTING

Retrospective review.

PATIENT SAMPLE

Two hundred ninety ACD patients.

OUTCOME MEASURES

Morbidity and mortality data.

METHODS

Operative ACD patients ≥18 years with pre-(BL) and 10-year (10Y) data were included. Patients were stratified as expired versus living, as well as temporally grouped by Expiration prior to 5Y or between 5Y and 10Y. Group differences were assessed via means comparison analysis. Backstep logistic regression identified mortality predictors. Kaplan-Meier analysis assessed survivorship of expired patients. Log rank analysis determined differences in survival distribution groups.

RESULTS

Sixty-six total patients were included (60.97±10.19 years, 48% female, 28.03±7.28 kg/m2). Within 10Y, 12 (18.2% of ACD cohort) expired. At baseline, patients were comparable in age, gender, BMI, and CCI total on average (all p>.05). Furthermore, patients were comparable in BL HRQLs (all p>.05). However, patients who expired between 5Y and 10Y demonstrated higher BL EQ5D and mJOA scores than their earlier expired counterparts at 2Y (p<.021). Furthermore, patients who presented with no CCI markers at BL were significantly more likely to survive until the 5Y-10Y follow-up window. Surgically, the only differences observed between patients who survived until 5Y was in undergoing osteotomy, with longer survival seen in those who did not require it (p=.003). Logistic regression revealed independent predictors of death prior to 5Y to be increased BMI, increased frailty, and increased levels fused (model p<.001). KM analysis found that by Passias et al frailty, not frail patients had mean survival time of 170.56 weeks, versus 158.00 in frail patients (p=.949).

CONCLUSIONS

Our study demonstrates that long-term survival after cervical deformity surgery may be predicted by baseline surgical factors. By optimizing BMI, frailty status, and minimizing fusion length when appropriate, surgeons may be able to further assist ACD patients in increasing their survivability postoperatively.

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.

Patient-Centered Outcomes Following Prone Lateral Single-Position Approach to Same-Day Circumferential Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVE

Evaluate surgical characteristics and postoperative 2-year results of the PL approach to spinal fusion.

SUMMARY OF BACKGROUND DATA

Prone-lateral(PL) single positioning has recently gained popularity in spine surgery due to lower blood loss and operative time but has yet to be examined for other notable outcomes, including realignment and patient-reported measures.

MATERIALS AND METHODS

We included circumferential spine fusion patients with a minimum one-year follow-up. Patients were stratified into groups based on undergoing PL approach versus same-day staged (Staged). Mean comparison tests identified differences in baseline parameters. Multivariable logistic regression, controlling for age, levels fused, and Charlson Comorbidity Index were used to determine the influence of the approach on complication rates, radiographic and patient-reported outcomes up to two years.

RESULTS

One hundred twenty-two patients were included of which 72(59%) were same-day staged and 50(41%) were PL. PL patients were older with lower body mass index (both P <0.05). Patients undergoing PL procedures had lower estimated blood loss and operative time (both P <0.001), along with fewer osteotomies (63% vs. 91%, P <0.001). This translated to a shorter length of stay (3.8 d vs. 4.9, P =0.041). PL procedures demonstrated better correction in both PT (4.0 vs. -0.2, P =0.033 and pelvic incidence and lumbar lordosis (-3.7 vs. 3.1, P =0.012). PL procedures were more likely to improve in GAP relative pelvic version (OR: 2.3, [1.5-8.8]; P =0.003]. PL patients suffered lesser complications during the perioperative period and greater improvement in NRS-Back (-6.0 vs. -3.3, P =0.031), with less reoperations (0.0% vs. 4.8%, P =0.040) by two years.

CONCLUSIONS

Patients undergoing PL single-position procedures received less invasive procedures with better correction of pelvic compensation, as well as earlier discharge. The prone lateral cohort also demonstrated greater clinical improvement and a lower rate of reoperations by two years following spinal corrective surgery.

LEVEL OF EVIDENCE

Level-III.

The Importance of Incorporating Proportional Alignment in Adult Cervical Deformity Corrections Relative to Regional and Global Alignment: Steps Toward Development of a Cervical-Specific Score

STUDY DESIGN/SETTING

Retrospective single-center study.

BACKGROUND

The global alignment and proportion score is widely used in adult spinal deformity surgery. However, it is not specific to the parameters used in adult cervical deformity (ACD).

PURPOSE

Create a cervicothoracic alignment and proportion (CAP) score in patients with operative ACD.

METHODS

Patients with ACD with 2-year data were included. Parameters consisted of relative McGregor's Slope [RMGS = (MGS × 1.5)/0.9], relative cervical lordosis [RCL = CL - thoracic kyphosis (TK)], Cervical Lordosis Distribution Index (CLDI = C2 - Apex × 100/C2 - T2), relative pelvic version (RPV = sacral slope - pelvic incidence × 0.59 + 9), and a frailty factor (greater than 0.33). Cutoff points were chosen where the cross-tabulation of parameter subgroups reached a maximal rate of meeting the Optimal Outcome. The optimal outcome was defined as meeting Good Clinical Outcome criteria without the occurrence of distal junctional failure (DJF) or reoperation. CAP was scored between 0 and 13 and categorized accordingly: ≤3 (proportioned), 4-6 (moderately disproportioned), >6 (severely disproportioned). Multivariable logistic regression analysis determined the relationship between CAP categories, overall score, and development of distal junctional kyphosis (DJK), DJF, reoperation, and Optimal Outcome by 2 years.

RESULTS

One hundred five patients with operative ACD were included. Assessment of the 3-month CAP score found a mean of 5.2/13 possible points. 22.7% of patients were proportioned, 49.5% moderately disproportioned, and 27.8% severely disproportioned. DJK occurred in 34.5% and DJF in 8.7%, 20.0% underwent reoperation, and 55.7% achieved Optimal Outcome. Patients severely disproportioned in CAP had higher odds of DJK [OR: 6.0 (2.1-17.7); P =0.001], DJF [OR: 9.7 (1.8-51.8); P =0.008], reoperation [OR: 3.3 (1.9-10.6); P =0.011], and lower odds of meeting the optimal outcome [OR: 0.3 (0.1-0.7); P =0.007] by 2 years, while proportioned patients suffered zero occurrences of DJK or DJF.

CONCLUSION

The regional alignment and proportion score is a method of analyzing the cervical spine relative to global alignment and demonstrates the importance of maintaining horizontal gaze, while also matching overall cervical and thoracolumbar alignment to limit complications and maximize clinical improvement.

Factors Influencing Maintenance of Alignment and Functional Improvement Following Adult Spinal Deformity Surgery: A 3-Year Outcome Analysis

STUDY DESIGN

This was a retrospective review.

OBJECTIVE

To assess the factors contributing to durability of surgical results following adult spinal deformity (ASD) surgery.

SUMMARY OF BACKGROUND

Factors contributing to the long-term sustainability of ASD correction are currently undefined.

MATERIALS AND METHODS

Operative ASD patients with preoperatively (baseline) and 3-year postoperatively radiographic/health-related quality of life data were included. At 1 and 3 years postoperatively, a favorable outcome was defined as meeting at least three of four criteria: (1) no proximal junctional failure or mechanical failure with reoperation, (2) best clinical outcome (BCO) for Scoliosis Research Society (SRS) (≥4.5) or Oswestry Disability Index (ODI) (<15), (3) improving in at least one SRS-Schwab modifier, and (4) not worsening in any SRS-Schwab modifier. A robust surgical result was defined as having a favorable outcome at both 1 and 3 years. Predictors of robust outcomes were identified using multivariable regression analysis with conditional inference tree for continuous variables.

RESULTS

We included 157 ASD patients in this analysis. At 1 year postoperatively, 62 patients (39.5%) met the BCO definition for ODI and 33 (21.0%) met the BCO for SRS. At 3 years, 58 patients (36.9%) had BCO for ODI and 29 (18.5%) for SRS. Ninety-five patients (60.5%) were identified as having a favorable outcome at 1 year postoperatively. At 3 years, 85 patients (54.1%) had a favorable outcome. Seventy-eight patients (49.7%) met criteria for a durable surgical result. Multivariable adjusted analysis identified the following independent predictors of surgical durability: surgical invasiveness >65, being fused to S1/pelvis, baseline to 6-week pelvic incidence and lumbar lordosis difference >13.9°, and having a proportional Global Alignment and Proportion score at 6 weeks.

CONCLUSIONS

Nearly 50% of the ASD cohort demonstrated good surgical durability, with favorable radiographic alignment and functional status maintained up to 3 years. Surgical durability was more likely in patients whose reconstruction was fused to the pelvis and addressed lumbopelvic mismatch with adequate surgical invasiveness to achieve full alignment correction.

Risk of spinal surgery among individuals who have been re-vascularized for coronary artery disease

HYPOTHESIS

Revascularization is a more effective intervention to reduce future postop complications.

METHODS

Patients undergoing elective spine fusion surgery were isolated in the PearlDiver database. Patients were stratified by having previous history of vascular stenting (Stent), coronary artery bypass graft (CABG), and no previous heart procedure (No-HP). Means comparison tests (chi-squared and independent samples t-tests, as appropriate) compared differences in demographics, diagnoses, and comorbidities. Binary logistic regression assessed the odds of 30-day and 90-day postoperative (postop) complications associated with each heart procedure (Odds Ratio [95 % confidence interval]). Statistical significance was set p < 0.05.

RESULTS

731,173 elective spine fusion patients included. Overall, 8,401 pts underwent a CABG, 24,037 pts Stent, and 698,735 had No-HP prior to spine fusion surgery. Compared to Stent and No-HP patients, CABG patients had higher rates of morbid obesity, chronic kidney disease, and diabetes (p < 0.001 for all). Meanwhile, stent patients had higher rates of PVD, hypertension, and hyperlipidemia (all p < 0.001). 30-days post-op, CABG patients had significantly higher complication rates including pneumonia, CVA, MI, sepsis, and death compared to No-HP (all p < 0.001). Stent patients vs. No-HF had higher 30-day post-op complication rates including pneumonia, CVA, MI, sepsis, and death. Furthermore, adjusting for age, comorbidities, and sex Stent was significantly predictive of a MI 30-days post-op (OR: 1.90 [1.53-2.34], P < 0.001). Additionally, controlling for levels fused, stent patients compared to CABG patients had 1.99x greater odds of a MI within 30-days (OR: 1.99 [1.26-3.31], p = 0.005) and 2.02x odds within 90-days postop (OR: 2.2 [1.53-2.71, p < 0.001).

CONCLUSION

With regards to spine surgery, coronary artery bypass graft remains the gold standard for risk reduction. Stenting does not appear to minimize risk of experiencing a post-procedure cardiac event as dramatically as CABG.

Impact of Frailty on the Development of Proximal Junctional Failure: Does Frailty Supersede Achieving Optimal Realignment?

BACKGROUND

Patients undergoing surgery for adult spinal deformity (ASD) are often elderly, frail, and at elevated risk of adverse events perioperatively, with proximal junctional failure (PJF) occurring relatively frequently. Currently, the specific role of frailty in potentiating this outcome is poorly defined.

PURPOSE

To determine if the benefits of optimal realignment in ASD, with respect to the development of PJF, can be offset by increasing frailty.

STUDY DESIGN

Retrospective cohort.

MATERIALS AND METHODS

Operative ASD patients (scoliosis >20°, SVA>5 cm, pelvic tilt>25°, or TK>60°) fused to the pelvis or below with available baseline and 2-year (2Y) radiographic and HRQL data were included. The Miller Frailty Index (FI) was used to stratify patients into 2 categories: Not Frail (FI <3) and Frail (>3). Proximal Junctional Failure (PJF) was defined using the Lafage criteria. "Matched" and "unmatched" refers to ideal age-adjusted alignment postoperatively. Multivariable regression determined the impact of frailty on the development of PJF.

RESULTS

Two hundred eighty-four ASD patients met inclusion criteria [62.2yrs±9.9, 81%F, BMI: 27.5 kg/m 2 ±5.3, ASD-FI: 3.4±1.5, Charlson Comorbidity Index (CCI): 1.7±1.6]. Forty-three percent of patients were characterized as Not Frail (NF) and 57% were characterized as Frail (F). PJF development was lower in the NF group compared with the F group (7% vs . 18%; P =0.002). F patients had 3.2 × higher risk of PJF development compared to NF patients (OR: 3.2, 95% CI: 1.3-7.3, P =0.009). Controlling for baseline factors, F unmatched patients had a higher degree of PJF (OR: 1.4, 95% CI:1.02-1.8, P =0.03); however, with prophylaxis, there was no increased risk. Adjusted analysis shows F patients, when matched postoperatively in PI-LL, had no significantly higher risk of PJF.

CONCLUSIONS

An increasingly frail state is significantly associated with the development of PJF after corrective surgery for ASD. Optimal realignment may mitigate the impact of frailty on eventual PJF. Prophylaxis should be considered in frail patients who do not reach ideal alignment goals.

Predictors of reoperation for spinal disorders in Chiari malformation patients with prior surgical decompression

Background

Chiari malformation (CM) is a cluster of related developmental anomalies of the posterior fossa ranging from asymptomatic to fatal. Cranial and spinal decompression can help alleviate symptoms of increased cerebrospinal fluid pressure and correct spinal deformity. As surgical intervention for CM increases in frequency, understanding predictors of reoperation may help optimize neurosurgical planning.

Materials and Methods

This was a retrospective analysis of the prospectively collected Healthcare Cost and Utilization Project's California State Inpatient Database years 2004-2011. Chiari malformation Types 1-4 (queried with ICD-9 CM codes) with associated spinal pathologies undergoing stand-alone spinal decompression (queried with ICD-9 CM procedure codes) were included. Cranial decompressions were excluded.

Results

One thousand four hundred and forty-six patients (29.28 years, 55.6% of females) were included. Fifty-eight patients (4.01%) required reoperation (67 reoperations). Patients aged 40-50 years had the most reoperations (11); however, patients aged 15-20 years had a significantly higher reoperation rate than all other groups (15.5% vs. 8.2%, P = 0.048). Female gender was significantly associated with reoperation (67.2% vs. 55.6%, P = 0.006). Medical comorbidities associated with reoperation included chronic lung disease (19% vs. 6.9%, P < 0.001), iron deficiency anemia (10.3% vs. 4.1%, P = 0.024), and renal failure (3.4% vs. 0.9%, P = 0.05). Associated significant cluster anomalies included spina bifida (48.3% vs. 34.8%, P = 0.035), tethered cord syndrome (6.9% vs. 2.1%, P = 0.015), syringomyelia (12.1% vs. 5.9%, P = 0.054), hydrocephalus (37.9% vs. 17.7%, P < 0.001), scoliosis (13.8% vs. 6.4%, P = 0.028), and ventricular septal defect (6.9% vs. 2.3%, P = 0.026).

Conclusions

Multiple medical and CM-specific comorbidities were associated with reoperation. Addressing them, where possible, may aid in improving CM surgery outcomes.

Concurrent Presence of Thoracolumbar Scoliosis and Chiari Malformation: Is Operative Risk Magnified?

STUDY DESIGN

Retrospective review of Kids' Inpatient Database (KID).

PURPOSE

Identify the risks and complications associated with surgery in adolescents diagnosed with Chiari and scoliosis.

OVERVIEW OF LITERATURE

Scoliosis is frequently associated with Chiari malformation (CM). More specifically, reports have been made about this association with CM type I in the absence of syrinx status.

METHODS

The KID was used to identify all pediatric inpatients with CM and scoliosis. The patients were stratified into three groups: those with concomitant CM and scoliosis (CMS group), those with only CM (CM group), and those with only scoliosis (Sc group). Multivariate logistic regressions were used to assess association between surgical characteristics and diagnosis with complication rate.

RESULTS

A total of 90,707 spine patients were identified (61.8% Sc, 37% CM, 1.2% CMS). Sc patients were older, had a higher invasiveness score, and higher Charlson comorbidity index (all p<0.001). CMS patients had significantly higher rates of surgical decompression (36.7%). Sc patients had significantly higher rates of fusions (35.3%) and osteotomies (1.2%, all p<0.001). Controlling for age and invasiveness, postoperative complications were significantly associated with spine fusion surgery for Sc patients (odds ratio [OR], 1.8; p<0.05). Specifically, posterior spinal fusion in the thoracolumbar region had a greater risk of complications (OR, 4.9) than an anterior approach (OR, 3.6; all p<0.001). CM patients had a significant risk of complications when an osteotomy was performed as part of their surgery (OR, 2.9) and if a spinal fusion was concurrently performed (OR, 1.8; all p<0.05). Patients in the CMS cohort were significantly likely to develop postoperative complications if they underwent a spinal fusion from both anterior (OR, 2.5) and posterior approach (OR, 2.7; all p<0.001).

CONCLUSIONS

Having concurrent scoliosis and CM increases operative risk for fusion surgeries despite approach. Being independently inflicted with scoliosis or Chiari leads to increased complication rate when paired with thoracolumbar fusion and osteotomies; respectively.

Natural history of adult spinal deformity: how do patients with suboptimal surgical outcomes fare relative to nonoperative counterparts?

OBJECTIVE

Management of adult spinal deformity (ASD) has increasingly favored operative intervention; however, the incidence of complications and reoperations is high, and patients may fail to achieve idealized postsurgical results. This study compared health-related quality of life (HRQOL) metrics between patients with suboptimal surgical outcomes and those who underwent nonoperative management as a proxy for the natural history (NH) of ASD.

METHODS

ASD patients with 2-year data were included. Patients who were offered surgery but declined were considered nonoperative (i.e., NH) patients. Operative patients with suboptimal outcome (SOp)-defined as any reoperation, major complication, or ≥ 2 severe Scoliosis Research Society (SRS)-Schwab modifiers at follow-up-were selected for comparison. Propensity score matching (PSM) on the basis of baseline age, deformity, SRS-22 Total, and Charlson Comorbidity Index score was used to match the groups. ANCOVA and stepwise logistic regression analysis were used to assess outcomes between groups at 2 years.

RESULTS

In total, 441 patients were included (267 SOp and 174 NH patients). After PSM, 142 patients remained (71 SOp 71 and 71 NH patients). At baseline, the SOp and NH groups had similar demographic characteristics, HRQOL, and deformity (all p > 0.05). At 2 years, ANCOVA determined that NH patients had worse deformity as measured with sagittal vertical axis (36.7 mm vs 21.3 mm, p = 0.025), mismatch between pelvic incidence and lumbar lordosis (11.9° vs 2.9°, p < 0.001), and pelvic tilt (PT) (23.1° vs 20.7°, p = 0.019). The adjusted regression analysis found that SOp patients had higher odds of reaching the minimal clinically important differences in Oswestry Disability Index score (OR [95% CI] 4.5 [1.7-11.5], p = 0.002), SRS-22 Activity (OR [95% CI] 3.2 [1.5-6.8], p = 0.002), SRS-22 Pain (OR [95% CI] 2.8 [1.4-5.9], p = 0.005), and SRS-22 Total (OR [95% CI] 11.0 [3.5-34.4], p < 0.001).

CONCLUSIONS

Operative patients with SOp still experience greater improvements in deformity and HRQOL relative to the progressive radiographic and functional deterioration associated with the NH of ASD. The NH of nonoperative management should be accounted for when weighing the risks and benefits of operative intervention for ASD.

Should Global Realignment Be Tailored to Frailty Status for Patients Undergoing Surgical Intervention for Adult Spinal Deformity?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Assess whether modifying spinal alignment goals to accommodate frailty considerations will decrease mechanical complications and maximize clinical outcomes.

SUMMARY OF BACKGROUND DATA

The Global Alignment and Proportion (GAP) score was developed to assist in reducing mechanical complications, but has had less success predicting such events in external validation. Higher frailty and many of its components have been linked to the development of implant failure. Therefore, modifying the GAP score with frailty may strengthen its ability to predict mechanical complications.

MATERIALS AND METHODS

We included 412 surgical ASD patients with two-year follow-up. Frailty was quantified using the modified Adult Spinal Deformity Frailty Index (mASD-FI). Outcomes: proximal junctional kyphosis and proximal junctional failure (PJF), major mechanical complications, and "Best Clinical Outcome" (BCO), defined as Oswestry Disability Index<15 and Scoliosis Research Society 22-item Questionnaire Total>4.5. Logistic regression analysis established a six-week score based on GAP score, frailty, and Oswestry Disability Index US Norms. Logistic regression followed by conditional inference tree analysis generated categorical thresholds. Multivariable logistic regression analysis controlling for confounders was used to assess the performance of the frailty-modified GAP score.

RESULTS

Baseline frailty categories: 57% not frail, 30% frail, 14% severely frail. Overall, 39 of patients developed proximal junctional kyphosis, 8% PJF, 21% mechanical complications, 22% underwent reoperation, and 15% met BCO. The mASD-FI demonstrated a correlation with developing PJF, mechanical complications, undergoing reoperation, and meeting BCO at two years (all P <0.05). Regression analysis generated the following equation: Frailty-Adjusted Realignment Score (FAR Score)=0.49×mASD-FI+0.38×GAP Score. Thresholds for the FAR score (0-13): proportioned: <3.5, moderately disproportioned: 3.5-7.5, severely disproportioned: >7.5. Multivariable logistic regression assessing FAR score demonstrated associations with mechanical complications, reoperation, and meeting BCO by two years (all P <0.05), whereas the original GAP score was only significant for reoperation.

CONCLUSION

This study demonstrated adjusting alignment goals in adult spinal deformity surgery for a patient's baseline frailty status and disability may be useful in minimizing the risk of complications and adverse events, outperforming the original GAP score in terms of prognostic capacity.

LEVEL OF EVIDENCE

III.

Surgical costs in adult cervical Deformity: Do higher cost surgeries lead to better Outcomes?

BACKGROUND

As our focus on delivering cost effective healthcare increases, interventions like cervical deformity surgery, which are associated with high resource utilization, have received greater scrutiny. The purpose of this study was to assess relationship between surgical costs, deformity correction, and patient reported outcomes in ACD surgery.

METHODS

ACD Patients ≥ 18 years with baseline (BL) and 2-year (2Y) data were included. Cost of surgery was calculated by applying average Medicare reimbursement rates by CPT code to surgical details of each patient in the cohort. CPT codes for corpectomy, ACDF, osteotomy, decompression, levels fused, and instrumentation were considered in the analysis. Costs of complications and reoperations were intentionally excluded from the cost analysis. Patients were ranked into two groups by surgical cost: lowest cost (LC) and highest cost (HC). ANCOVA assessed differences in outcomes while accounting for covariates as appropriate.

RESULTS

113 met inclusion criteria. While mean age, frailty, BMI and gender composition were similar between cost groups, mean CCI was significantly higher in the HC group compared to that of the LC group (p=.014). At baseline, LC and HC groups had similar HRQLs and radiographic deformity (all p >.05). Logistic regression accounting for baseline age, deformity and CCI found that HC patients had significantly lower odds of undergoing reoperation within 2-years (OR: 0.309, 95 % CI: 0.193 - 0.493, p <.001). Furthermore, logistic regression accounting for baseline age, deformity and CCI found odds of DJF were significantly lower for those in the HC group (OR: 0.163, 95 % CI: 0.083 - 0.323, p <.001). At 2-years, logistic regression accounting for age and baseline TS-CL found HC patients still had significantly higher odds of reaching a "0″ TS-CL modifier at 2-years (OR: 3.353, 95 % CI: 1.081 - 10.402, p=.036). Logistic regression accounting for age and baseline NDI score found HC patients had significantly higher odds of reaching MCID in NDI at 2-years (OR: 4.477, 95 % CI: 1.507 - 13.297, p=.007). A similar logistic regression accounting for age and baseline mJOA score found odds of reaching MCID in mJOA significantly higher for high-cost patients (OR: 2.942, 95 % CI: 1.101 - 7.864, p=.031).

CONCLUSIONS

While patient presentation influences surgical planning and costs, this study attempted to control for such variations to assess impact of surgical costs on outcomes. Despite continued scrutiny over healthcare costs, we found that more costly surgical interventions can produce superior radiographic alignment as well as patient reported outcomes for patients with cervical deformity.

Long-term Morbidity in Patients Following Surgical Correction of Adult Spinal Deformity: Results from a Cohort with Minimum 5 Year Follow-up

STUDY DESIGN

Retrospective.

OBJECTIVE

To describe the rate of post-operative morbidity before and after 2-year follow-up for patients undergoing surgical correction of adult spinal deformity.

SUMMARY OF BACKGROUND DATA

Advances in modern surgical techniques for deformity surgery have shown promising short-term clinical results. However, the permanence of radiographic correction, mechanical complications, and revision surgery in adult spinal deformity (ASD) surgery remains a clinical challenge. Little information exists on the incidence of long-term morbidity beyond the acute post-operative window.

METHODS

ASD patients with complete baseline (BL) and 5-year (5Y) health related quality of life (HRQL) and radiographic data were included. Rates of adverse events, including proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and reoperations up to 5Y were documented. Primary and revision surgeries were compared. We used logistic regression analysis to adjust for demographic and surgical confounders.

RESULTS

Of 118 patients eligible for 5Y follow up, 99(83.9%) had complete follow-up data. The majority were female (83%), mean age 54.1 yrs and 10.4 levels fused and 14 undergoing 3-CO. 33 patients had a prior fusion and 66 were primary cases. By 5Y postop the cohort had a adverse event rate of 70.7% with 25(25.3%) sustaining a major complication and 26(26.3%) receiving reoperation. 38 (38.4%) developed PJK by 5Y and 3 (4.0%) developed PJF. The cohort had a significantly higher rate of complications (63.6% vs. 19.2%), PJK (34.3% vs. 4.0%), and reoperations (21.2% vs. 5.1%) before 2Y, all P<0.01. The most common complications beyond 2Y were mechanical complications.

CONCLUSIONS

While incidence of adverse events was high before two years, there was a substantial reduction in longer follow-up indicating complications after two years are less common. Complications beyond two years consisted mostly of mechanical issues.

A Hierarchical Approach to Realignment Strategies in Adult Cervical Deformity Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Construct an individualized cervical realignment strategy based on patient parameters at the presentation that results in superior 2-year health-related quality of life metrics and decreased rates of junctional failure and reoperation following adult cervical deformity surgery.

SUMMARY OF BACKGROUND DATA

Research has previously focused on adult cervical deformity realignment thresholds for maximizing clinical outcomes while minimizing complications. However, realignment strategies may differ based on patient presentation and clinical characteristics.

METHODS

We included adult cervical deformity patients with 2-year data. The optimal outcome was defined as meeting good clinical outcomes without distal junctional failure or reoperation. Radiographic parameters assessed included C2 Slope, C2-C7, McGregor's slope, TS-CL, cSVA, T1 slope, and preoperative lowest-instrumented vertebra (LIV) inclination angle. Conditional inference trees were used to establish thresholds for each parameter based on achieving the optimal outcome. Analysis of Covariance and multivariable logistic regression analysis, controlling for age, comorbidities, baseline deformity and disability, and surgical factors, assessed outcome rates for the hierarchical approach within each deformity group.

RESULTS

One hundred twenty-seven patients were included. After correction, there was a significant difference in meeting the optimal outcome when correcting the C2 slope below 10 degrees (85% vs. 34%, P <0.001), along with lower rates of distal junctional failure (DJF) (7% vs. 42%, P <0.001). Next, after isolating patients below the C2 slope threshold, the selection of LIV with an inclination between 0 and 40 degrees demonstrated lower rates of distal junctional kyphosis and higher odds of meeting optimal outcome(OR: 4.2, P =0.011). The best third step was the correction of cSVA below 35 mm. This hierarchical approach (11% of the cohort) led to significantly lower rates of DJF (0% vs. 15%, P <0.007), reoperation (8% vs. 28%, P <0.001), and higher rates of meeting optimal outcome (93% vs. 36%, P <0.001) when controlling for age, comorbidities, and baseline deformity and disability.

CONCLUSION

Our results indicate that the correction of C2 slope should be prioritized during cervical deformity surgery, with the selection of a stable LIV and correction of cervical SVA below the idealized threshold. Among the numerous radiographic parameters considered during preoperative planning for cervical deformity correction, our determinations help surgeons prioritize those realignment strategies that maximize the health-related quality of life outcomes and minimize complications.

LEVEL OF EVIDENCE

Level-III.

External Validation of the National Surgical Quality Improvement Program Calculator Utilizing a Single Institutional Experience for Adult Spinal Deformity Corrective Surgery

BACKGROUND

Identify the external applicability of the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) risk calculator in the setting of adult spinal deformity (ASD) and subsets of patients based on deformity and frailty status.

METHODS

ASD patients were isolated in our single-center database and analyzed for the shared predictive variables displayed in the NSQIP calculator. Patients were stratified by frailty (not frail <0.03, frail 0.3-0.5, severely frail >0.5), deformity [T1 pelvic angle (TPA) > 30, pelvic incidence minus lumbar lordosis (PI-LL) > 20], and reoperation status. Brier scores were calculated for each variable to validate the calculator's predictability in a single center's database (Quality). External validity of the calculator in our ASD patients was assessed via Hosmer-Lemeshow test, which identified whether the differences between observed and expected proportions are significant.

RESULTS

A total of 1606 ASD patients were isolated from the Quality database (48.7 years, 63.8% women, 25.8 kg/m²); 33.4% received decompressions, and 100% received a fusion. For each subset of ASD patients, the calculator predicted lower outcome rates than what was identified in the Quality database. The calculator showed poor predictability for frail, deformed, and reoperation patients for the category "any complication" because they had Brier scores closer to 1. External validity of the calculator in each stratified patient group identified that the calculator was not valid, displaying P values >0.05.

CONCLUSION

The NSQIP calculator was not a valid calculator in our single institutional database. It is unable to comment on surgical complications such as return to operating room, surgical site infection, urinary tract infection, and cardiac complications that are typically associated with poor patient outcomes. Physicians should not base their surgical plan solely on the NSQIP calculator but should consider multiple preoperative risk assessment tools.

LEVEL OF EVIDENCE: 3

Failure to Normalize Risk Profile of Spine Fusion Patients With Coronary Artery Disease Previously Treated With Percutaneous Stent Revascularization

BACKGROUND

The impact of an initially less invasive cardiac intervention on outcomes of future surgical spine procedures has been understudied; therefore, we sought to investigate the effect of coronary stents on postoperative outcomes in an elective spine fusion cohort.

METHODS

Elective spine fusion patients were isolated with International Classification of Diseases-Ninth Edition and current procedural terminology procedure codes in the PearlDiver database. Patients were stratified by number of coronary stents: (1) 1 to 2 stents (ST12); (2) 3 to 4 stents (ST34); (3) no stents. Mean comparison tests compared differences in demographics, diagnoses, comorbidities, and 30-day and 90-day complication outcomes. Logistic regression assessed the odds of complications associated with coronary stents, controlling for levels fused, age, sex, and comorbidities (odds ratio [95% confidence interval]). Statistical significance was P < 0.05.

RESULTS

A total of 726,061 elective spine fusion patients were isolated. Of those patients, 707,396 patients had no stent, 17,087 ST12, and 1578 ST34. At baseline (BL), ST12 patients had higher rates of morbid obesity, chronic kidney disease, congestive heart failure, chronic obstructive pulmonary disease, and diabetes mellitus compared with no stent and ST34 patients (all P < 0.001). Relative to no stent patients, ST12 patients had a longer length of stay and, at 30 days, significantly higher complication rates, including pneumonia, myocardial infarction (MI), sepsis, acute kidney injury, urinary tract infection (UTI), wound complications, transfusions, and 30-day readmissions (P < 0.05). Controlling for age, sex, comorbidities, and levels fused, ST12 was a significant predictor of MI within 30 days (OR 2.15 [95% CI 1.7-2.7], P < 0.001) and 90 days postoperatively (OR 1.87 [95% CI 1.6-2.2], P < 0.001). ST34 patients compared with no stent patients at 30 days presented with increased rates of complication, including pneumonia, MI, sepsis, UTI, wound complications, and 30-day readmissions. Regression analysis showed no significant differences in complications between ST12 vs ST34 at 30 days, but at 90 days, ST34 was associated with significantly increased rate and odds of death (1.1% vs 0.3%, P = 0.021; OR 1.94 [95% CI 1.13-3.13], P = 0.01).

CONCLUSION

Cardiac stents failed to normalize risk profile of patients with coronary artery disease. Postoperatively at 90 days, elective spine fusion patients with 3 or more stents were significantly at risk of mortality compared with patients with fewer or no stents.

LEVEL OF EVIDENCE: 3

The Effects of Global Alignment and Proportionality Scores on Postoperative Outcomes After Adult Spinal Deformity Correction

BACKGROUND

Recent studies have suggested achieving global alignment and proportionality (GAP) alignment may influence mechanical complications after adult spinal deformity (ASD) surgery.

OBJECTIVE

To investigate the association between the GAP score and mechanical complications after ASD surgery.

METHODS

Patients with ASD with at least 5-level fusion to pelvis and minimum 2-year data were included. Multivariate analysis was used to find an association between proportioned (P), GAP-moderately disproportioned, and severely disproportioned (GAP-SD) states and mechanical complications (inclusive of proximal junctional kyphosis [PJK], proximal junctional failure [PJF], and implant-related complications [IC]). Severe sagittal deformity was defined by a "++" in the Scoliosis Research Society (SRS)-Schwab criteria for sagittal vertebral axis or pelvic incidence and lumbar lordosis.

RESULTS

Two hundred ninety patients with ASD were included. Controlling for age, Charlson comorbidity index, invasiveness and baseline deformity, and multivariate analysis showed no association of GAP-moderately disproportioned patients with proximal junctional kyphosis, PJF, or IC, while GAP-SD patients showed association with IC (odds ratio [OR]: 1.7, [1.1-3.3]; P = .043). Aligning in GAP-relative pelvic version led to lower likelihood of all 3 mechanical complications (all P < .04). In patients with severe sagittal deformity, GAP-SD was predictive of IC (OR: 2.1, [1.1-4.7]; P = .047), and in patients 70 years and older, GAP-SD was also predictive of PJF development (OR: 2.5, [1.1-14.9]; P = .045), while improving in GAP led to lower likelihood of PJF (OR: 0.2, [0.02-0.8]; P = .023).

CONCLUSION

Severely disproportioned in GAP is associated with development of any IC and junctional failure specifically in older patients and those with severe baseline deformity. Therefore, incorporation of patient-specific factors into realignment goals may better strengthen the utility of this novel tool.

The psychological burden of disease among patients undergoing cervical spine surgery: Are we underestimating our patients' inherent disability?

BACKGROUND

Studies have utilized psychological questionnaires to identify the psychological distress among certain surgical populations.

RESEARCH QUESTION

Is there an additional psychological burden among patients undergoing surgical treatment for their symptomatic degenerative cervical disease?

MATERIALS AND METHODS

Patients>18 years of age with symptomatic, degenerative cervical spine disease were included and prospectively enrolled. Correlations and multivariable logistic regression analysis assessed the relationship between these mental health components (PCS, FABQ) and the severity of disability described by the NDI, EQ-5D, and mJOA score. Patient distress scores were compared to previously published benchmarks for other diagnoses.

RESULTS

47 patients were enrolled (age: 56.0 years,BMI: 29.7kg/m²). Increasing neck disability and decreasing EQ-5D were correlated with greater PCS and FABQ(all P<0.001). Patients with severe psychological distress at baseline were more likely to report severe neck disability, while physician-reported mJOA had weaker associations. Compared to historical controls of lumbar patients, patients in our study had greater levels of psychological distress, as measured by FABQ (40.0 vs. 17.6; P<0.001) and PCS (27.4 vs. 19.3;P<0.001).

DISCUSSION AND CONCLUSION

Degenerative cervical spine patients seeking surgery were found to have a significant level of psychological distress, with a large portion reporting severe fear avoidance beliefs and catastrophizing pain at baseline. Strong correlation was seen between patient-reported functional metrics, but less so with physician-reported signs and symptoms. Additionally, this population demonstrated higher psychological burden in certain respects than previously identified benchmarks of patients with other disorders. Preoperative treatment to help mitigate this distress, impact postoperative outcomes, and should be further investigated.

LEVEL OF EVIDENCE

Level III.

Defining age-adjusted spinopelvic alignment thresholds: should we integrate BMI?

PURPOSE

To develop age- and BMI-adjusted alignment targets to improve patient-specific management and operative treatment outcomes.

METHODS

Retrospective review of a single-center stereographic database. ASD patients receiving operative or non-operative treatment, ≥ 18y/o with complete baseline (BL) ODI scores and radiographic parameters (PT, SVA, PILL, TPA) were included. Patients were stratified by age consistent with US-Normative values (norms) of SF-36(< 35, 35-55, 45-54, 55-64, 65-74, ≥ 75y/o), and dichotomized by BMI (Non-Obese < 30; Obese ≥ 30). Linear regression analysis established normative age- and BMI-specific radiographic thresholds, utilizing previously published age-specific US-Normative ODI values converted from SF-36 PCS (Lafage et al.), in conjunction with BL age and BMI means.

RESULTS

486 patients were included (Age: 52.5, Gender: 68.7%F, mean BMI: 26.2, mean ODI: 32.7), 135 of which were obese. Linear regression analysis developed age- and BMI-specific alignment thresholds, indicating PT, SVA, PILL, and TPA to increase with both increased age and increased BMI (all R > 0.5, p < 0.001). For non-obese patients, PT, SVA, PILL, and TPA ranged from 10.0, - 25.8, - 9.0, 3.1 in patients < 35y/o to 27.8, 53.4, 17.7, 25.8 in patients ≥ 75 y/o. Obese patients' PT, SVA, PILL, and TPA ranged from 10.5, - 7.6, - 7.1, 5.8 in patients < 35 y/o to 28.3, 67.0, 19.15, 27.7 in patients ≥ 75y/o. Normative SVA values in obese patients were consistently ≥ 10 mm greater compared to non-obese values, at all ages.

CONCLUSION

Significant associations exist between age, BMI, and sagittal alignment. While BMI influenced age-adjusted alignment norms for PT, SVA, PILL, and TPA at all ages, obesity most greatly influenced SVA, with normative values similar to non-obese patients who were 10 years older. Age-adjusted alignment thresholds should take BMI into account, calling for less rigorous alignment objectives in older and obese patients.

The Inherent Value of Preoperative Optimization-Absolute and Incremental Reduction in Components of Metabolic Syndrome Can Enhance Recovery and Minimize Perioperative Burden

BACKGROUND

Metabolic syndrome (MetS) is an amalgamation of medical disorders that ultimately increase patient complications. Factors such as obesity, hypertension, dyslipidemia, and diabetes are associated with this disease complex.

OBJECTIVE

To assess the incremental value of improving MetS in relation to clinical outcomes.

STUDY DESIGN

Retrospective cohort study.

METHODS

Patients undergoing elective spine surgery were isolated and separated into 2 groups: MetS patients (>2 metabolic variables: hypertension, diabetes, obesity, and triglycerides) and nonmetabolic patients (<2 metabolic variables). T tests and χ ² tests compared differences in patient demographics. Resolution of metabolic factors was incrementally analyzed for their effect on perioperative complications through utilization of logistic regressions.

RESULTS

A total of 2,855,517 elective spine patients were included. Of them, 20.1% had MeTS (81.4% two factors, 18.4% three factors, 0.2% four factors). MetS patients were older, less female, and more comorbid (P < 0.001). About 28.8% MetS patients developed more complications such as anemia (9.8% vs 5.9%), device related (3.5% vs 2.9%), neurologic (2.3% vs 1.4%), and bowel issues (9.7% vs 6.8 %; P < 0.05). Controlling for age and procedure invasiveness, having 3 MetS factors increased a patient's likelihood (0.89×) of developing a perioperative complication (P < 0.05), whereas 2 factors had lower odds (0.82). More specifically, patients who were diabetes, obese, and had hypertension had the greatest odds at developing a complication (0.58 [0.58-0.57]) followed by those who had concomitant hypertension, high triglycerides, and were obese (0.55 [0.63-0.48]; all P < 0.001). MetS patients with 2 factors, being obese and having hypertension produced the lowest odds at developing a complication (0.5 [0.61-0.43]; P < 0.001). These MetS patients also had a lower length of stay than those with 3 and 4 (P < 0.001).

CONCLUSIONS

Metabolic patients improved in perioperative complications incrementally, demonstrating the utility of efforts to mitigate burden of MetS even if not completely abolished.

CLINICAL RELEVANCE

This review contributes to the assessment of MetS optimization in the field of adult spine surgery.

LEVEL OF EVIDENCE: 3

"Reverse roussouly": cervicothoracic curvature ratios define characteristic shapes in adult cervical deformity

PURPOSE

To investigate normal curvature ratios of the cervicothoracic spine and to establish radiographic thresholds for severe myelopathy and disability, within the context of shape.

METHODS

Adult cervical deformity (CD) patients undergoing cervical fusion were included. C2-C7 Cobb angle (CL) and thoracic kyphosis (TK), using T2-T12 Cobb angle, were used as a ratio, ranging from -1 to + 1. Pearson bivariate r and univariate analyses analyzed radiographic correlations and differences in myelopathy(mJOA > 14) or disability(NDI > 40) across ratio groups.

RESULTS

Sixty-three CD patients included. Regarding CL:TK ratio, 37 patients had a negative ratio and 26 patients had a positive ratio. A more positive CL:TK correlated with increased TS-CL(r = 0.655, p =  < 0.001)and mJOA(r = 0.530, p = 0.001), but did not correlate with cSVA/SVA or NDI scores. A positive CL:TK ratio was associated with moderate disability(NDI > 40)(OR: 7.97[1.22-52.1], p = 0.030). Regression controlling for CL:TK ratio revealed cSVA > 25 mm increased the odds of moderate to severe myelopathy and cSVA > 30 mm increased the odds of significant neck disability. Lastly, TS-CL > 29 degrees increased the odds of neck disability by 4.1 × with no cutoffs for severe mJOA(p > 0.05).

CONCLUSIONS

Cervical deformity patients with an increased CL:TK ratio had higher rates of moderate neck disability at baseline, while patients with a negative ratio had higher rates of moderate myelopathy clinically. Specific thresholds for cSVA and TS-CL predicted severe myelopathy or neck disability scores, regardless of baseline neck shape. A thorough evaluation of the cervical spine should include exploration of relationships with the thoracic spine and may better allow spine surgeons to characterize shapes and curves in cervical deformity patients.

Improved Surgical Correction Relative to Patient-Specific Ideal Spinopelvic Alignment Reduces Pelvic Nonresponse for Severely Malaligned Adult Spinal Deformity Patients

BACKGROUND

Persistent pelvic compensation following adult spinal deformity (ASD) corrective surgery may impair quality of life and result in persistent pathologic lower extremity compensation. Ideal age-specific alignment targets have been proposed to improve surgical outcomes, though it is unclear whether reaching these ideal targets reduces rates of pelvic nonresponse following surgery. Our aim was to assess the relationship between pelvic nonresponse, age-specific alignment, and lower-limb compensation following surgery for ASD.

METHODS

Single-center retrospective cohort study. ASD patients were grouped: those who did not improve in Scoliosis Research Society-Schwab pelvic tilt (PT) modifier (pelvic nonresponders [PNR]), and those who improved (pelvic responders [PR]). Groups were propensity score matched for preoperative PT and assessed for differences in spinal and lower extremity alignment. Rates of pelvic nonresponse were compared across patient groups who were undercorrected, overcorrected, or matched age-specific postoperative alignment targets.

RESULTS

A total of 146 surgical ASD patients, 47.9% of whom showed pelvic nonresponse following surgery, were included. After propensity score matching, PNR (N = 29) and PR (N = 29) patients did not differ in demographics, preoperative alignment, or levels fused; however, PNR patients have less preoperative knee flexion (9° vs 14°, P = 0.043). PNR patients had inferior postoperative pelvic incidence and lumbar lordosis (PI-LL) alignment (17° vs 3°) and greater pelvic shift (53 vs 31 mm). PNR and PR patients did not differ in rates of reaching ideal age-specific postoperative alignment for sagittal vertical axis (SVA) or PI-LL, though patients who matched ideal PT had lower rates of PNR (25.0% vs 75.0%). For patients with moderate and severe preoperative SVA, more aggressive correction relative to either ideal postoperative PT or PI-LL was associated with significantly lower rates of pelvic nonresponse (all P < 0.05).

CONCLUSIONS

For patients with moderate to severe baseline truncal inclination, more aggressive surgical correction relative to ideal age-specific PI-LL was associated with lower rates of pelvic nonresponse. Postoperative alignment targets may need to be adjusted to optimize alignment outcomes for patients with substantial preoperative sagittal deformity.

CLINICAL RELEVANCE

These findings increase our understanding of the poor outcomes that occur despite ideal realignment. Surgical correction of severe global sagittal deformity should be prioritized to mitigate these occurrences.

LEVEL OF EVIDENCE: 3

Do the newly proposed realignment targets for C2 and T1 slope bridge the gap between radiographic and clinical success in corrective surgery for adult cervical deformity?

OBJECTIVE

Surgical correction of cervical deformity (CD) has been associated with superior alignment and functional outcomes. It has not yet been determined whether baseline or postoperative T1 slope (T1S) and C2 slope (C2S) correlate with health-related quality-of-life (HRQoL) metrics and radiographic complications, such as distal junctional kyphosis (DJK) and distal junctional failure (DJF). The objective of this study was to determine the impact of T1S and C2S deformity severity on HRQoL metrics and DJF development in patients with CD who underwent a cervical fusion procedure.

METHODS

All operative CD patients with upper instrumented vertebra above C7 and preoperative (baseline) and up to 2-year postoperative radiographic and HRQoL data were included. CD was defined as meeting at least one of the following radiographic parameters: C2-7 lordosis < -15°, TS1-cervical lordosis mismatch > 35°, segmental cervical kyphosis > 15° across any 3 vertebrae between C2 and T1, C2-7 sagittal vertical axis > 4 cm, McGregor's slope > 20°, or chin-brow vertical angle > 25°. Spearman's rank-order correlation and linear regression analysis assessed the impact of T1S and C2S on HRQoL metrics (Neck Disability Index [NDI], modified Japanese Orthopaedic Association [mJOA] scale, EuroQOL 5-Dimension Questionnaire [EQ-5D] visual analog scale [VAS] score, and numeric rating scale [NRS]-neck) and complications (DJK, DJF, reoperation). Logistic regression and a conditional inference tree (CIT) were used to determine radiographic thresholds for achieving optimal clinical outcome, defined as meeting good clinical outcome criteria (≥ 2 of the following: NDI < 20 or meeting minimal clinically important difference, mild myelopathy [mJOA score ≥ 14], and NRS-neck ≤ 5 or improved by ≥ 2 points), not undergoing reoperation, or developing DJF or mechanical complication by 2 years.

RESULTS

One hundred five patients with CD met inclusion criteria. By surgical approach, 14.7% underwent an anterior-only approach, 46.1% a posterior-only approach, and 39.2% combined anterior and posterior approaches. The mean baseline radiographic parameters were T1S 28.3° ± 14.5° and C2S 25.9° ± 17.5°. Significant associations were found between 3-month C2S and mJOA score (r = -0.248, p = 0.034), NDI (r = 0.399, p = 0.001), EQ-5D VAS (r = -0.532, p < 0.001), NRS-neck (r = 0.239, p = 0.040), and NRS-back (r = 0.264, p = 0.021), while significant correlation was also found between 3-month T1S and mJOA score (r = -0.314, p = 0.026), NDI (r = 0.445, p = 0.001), EQ-5D VAS (r = -0.347, p = 0.018), and NRS-neck (r = 0.269, p = 0.049). A significant correlation was also found between development of DJF and 3-month C2S (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.01-1.1, p = 0.015) as well as for T1S (OR 1.1, 95% CI 1.01-1.1, p = 0.023). Logistic regression with CIT identified thresholds for optimal outcome by 2 years: optimal 3-month T1S < 26° (OR 5.6) and C2S < 10° (OR 10.4), severe 3-month T1S < 45.5° (OR 0.2) and C2S < 38.0° (no patient above this threshold achieved optimal outcome; all p < 0.05). Patients below both optimal thresholds achieved rates of 0% for DJK and DJF, and 100% met optimal outcome.

CONCLUSIONS

The severity of CD, defined by T1S and C2S at baseline and especially at 3 months, can be predictive of postoperative functional improvement and occurrence of worrisome complications in patients with CD, necessitating the use of thresholds in surgical planning to achieve optimal outcomes.

The Prevalence of Hip Pathologies in Adolescent Idiopathic Scoliosis

Background

Adolescent idiopathic scoliosis (AIS) is the most common form of abnormal spine curvature observed in patients age 10 to 18. Typically characterized by shoulder height and waistline asymmetry, AIS may drive uneven distribution of force in the hips, leading to increased rates of concurrent hip diagnoses. The relationship between AIS and concurrent hip diagnoses is underexplored in the literature, and to date, there has been little research comparing rates of hip diagnoses between patients with AIS and those unaffected.

Purpose

Assess differences in rates and clusters of hip diagnoses between patients with AIS and those unaffected.

Study design

Retrospective review of Healthcare Cost and Utilization Project's (HCUP) Nationwide Inpatient Sample (NIS).

Patient sample

224,504 weighted inpatient discharges.

Outcome measures

Rates of hip diagnoses.

Methods

Patients in the NIS database (2005-2013) ages 10-18 years were isolated. Patients were grouped by those diagnosed with AIS (ICD-9: 737.30) and those unaffected. Patient groups were propensity score matched (PSM) for age. Means comparison tests assessed differences in demographic, comorbidity, and diagnosis profiles between patient groups for corresponding age categories. ICD-9 codes were used to identify specific hip diagnoses.

Results

Following PSM, 24,656 AIS and 24,656 unaffected patients were included. The AIS patient group was comprised of more females (66% vs 59%) and had lower rates of obesity (2.4% vs 3.5%, both p < 0.001). Overall, 1.1% of patients had at least one hip diagnosis: congenital deformity (0.31%), developmental dysplasia (0.24%), recurrent dislocation (0.18%), isolated dislocation (0.09%), osteonecrosis (0.08%), osteochondrosis (0.07%), acquired deformity (0.03%), and osteoarthritis (0.02%). AIS patients had lower rates of osteonecrosis (0.04% vs 0.12%, p = 0.003), but higher rates of all other hip diagnoses, including dysplasia (0.41% vs 0.07%, p < 0.001), recurrent dislocation (0.32% vs 0.03%, p < 0.001), isolated dislocation (0.13% vs 0.06%, p < 0.001), and osteoarthritis (0.04% vs 0.01%, p = 0.084. Co-occurrences of hip diagnoses were relatively rare, with 0.03% patients having more than one hip diagnosis. Rates of co-occurring hip diagnoses did not differ between AIS and unaffected groups (0.04% vs 0.02%, p = 0.225).

Conclusions

Compared to unaffected patients of similar ages, patients with AIS had higher overall rates of hip diagnoses, including dysplasia and recurrent dislocation. A higher trend of precocious osteoarthritis was also observed at a higher rate in AIS patients, although this difference was not statistically significant. Our results present an argument for surgical realignment in the coronal and sagittal planes to neutralize asymmetrical forces in the hips, and suggest the need for increased awareness and clinical screening for hip-related disorders in AIS patients.

Level of Evidence

III.

Cervical and spinopelvic parameters can predict patient reported outcomes following cervical deformity surgery

Background:

Recent studies have evaluated the correlation of health-related quality of life (HRQL) scores with radiographic parameters. This relationship may provide insight into the connection of patient-reported disability and disease burden caused by cervical diagnoses.

Purpose:

To evaluate the association between spinopelvic sagittal parameters and HRQLs in patients with primary cervical diagnoses.

Methods:

Patients ≥18 years meeting criteria for primary cervical diagnoses. Cervical radiographic parameters assessed cervical sagittal vertical axis, TS-CL, chin-to-brow vertical angle, C2-T3, CL, C2 Slope, McGregor's slope. Global radiographic alignment parameters assessed PT, SVA, PI-LL, T1 Slope. Pearson correlations were run for all combinations at baseline (BL) and 1 year (1Y) for continuous BL and 1Y modified Japanese Orthopaedic Association scale (mJOA) scores, as well as decline or improvement in those HRQLs at 1Y. Multiple linear regression models were constructed to investigate BL and 1Y alignment parameters as independent variables.

Results:

Ninety patients included 55.6 ± 9.6 years, 52% female, 30.7 ± 7kg/m². By approach, 14.3% of patients underwent procedures by anterior approach, 56% posterior, and 30% had combined approaches. Average anterior levels fused: 3.6, posterior: 4.8, and mean total number of levels fused: 4.5. Mean operative time for the cohort was 902.5 minutes with an average estimated blood loss of 830 ccs. The mean BL neck disability index (NDI) score was 56.5 and a mJOA of 12.81. While BL NDI score correlated with gender (P = 0.050), it did not correlate with BL global or cervical radiographic factors. An increased NDI score at 1Y postoperatively correlated with BL body mass index (P = 0.026). A decreased NDI score was associated with 1Y T12-S1 angle (P = 0.009) and 1Y T10 L2 angle (P = 0.013). Overall, BL mJOA score correlated with the BL radiographic factors of T1 slope (P = 0.005), cervical lordosis (P = 0.001), C2-T3 (P = 0.008), C2 sacral slope (P = 0.050), SVA (P = 0.010), and CL Apex (P = 0.043), as well as gender (P = 0.050). Linear regression modeling for the prior independent variables found a significance of P = 0.046 and an R² of 0.367. Year 1 mJOA scores correlated with 1Y values for maximum kyphosis (P = 0.043) and TS-CL (P = 0.010). At 1Y, a smaller mJOA score correlated with BL S1 sacral slope (P = 0.014), pelvic incidence (P = 0.009), L1-S1 (P = 0.012), T12-S1 (P = 0.008). The linear regression model for those 4 variables demonstrated an R² of 0.169 and a P = 0.005. An increased mJOA score correlated with PI-LL difference at 1Y (P = 0.012), L1-S1 difference (P = 0.036), T12-S1 difference (0.006), maximum lordosis (P = 0.026), T9-PA difference (P = 0.010), and difference of T4-PA (P = 0.008).

Conclusions:

While the impact of preoperative sagittal and cervical parameters on mJOA was strong, the BL radiographic factors did not impact NDI scores. PostOp HRQL was significantly associated with sagittal parameters for mJOA (both worsening and improvement) and NDI scores (improvement). When cervical surgery has been indicated, radiographic alignment is important for postoperative HRQL.

Establishing the minimal clinically important difference for the PROMIS Physical domains in cervical deformity patients

INTRODUCTION

Patient Reported Outcome Measurement Information System (PROMIS) instruments have been shown to correlate with established patient outcome metrics. The aim of this retrospective study was to determine the MCID for the PROMIS physical domains of Physical Function (PF), Pain Intensity (PI), and Pain Interference (Int) in a population of surgical cervical deformity (CD) patients.

METHODS

Surgical CD patients ≥ 18 years old with baseline (BL) and 3-month (3 M) HRQL data were isolated. Changes in HRQLs: ΔBL-3M. An anchor-based methodology was used. The cohort was divided into four groups: 'worse' (ΔEQ5D ≤ -0.12), 'unchanged' (≥0.12, but < -0.12), 'slightly improve' (>0.12, but ≤ 0.24), and 'markedly improved' (>0.24) [0.24 is the MCID for EQ5D]. PROMIS-PF, PI and Int at 3M was compared between 'slightly improved' and 'unchanged'. ROC computed discrete MCID values using the change in PROMIS that yielded the smallest difference between sensitivity ('slightly improved') and specificity ('unchanged'). We repeated anchor-based methods for the Ames-ISSG classification of severe deformity.

RESULTS

140 patients were included. EQ5D groups: 9 patients 'worse', 53 'unchanged', 20 'slightly improved', and 57 'markedly improved'. Patients classified as 'unchanged' exhibited a PROMIS-PF improvement of 2.9 ± 17.0 and those 'slightly improved' had an average gain of 13.3 ± 17.8. ROC analysis for the PROMIS-PF demonstrated an MCID of +2.26, for PROMIS-PI of -5.5, and PROMIS-Int of -5.4. In the Ames-ISSG TS-CL severe CD modifier, ROC analysis found MCIDs of PROMIS physical domains: PF of +0.5, PI of -5.2, and Int of -5.4.

CONCLUSIONS

MCID for PROMIS physical domains were established for a cervical deformity population. MCID in PROMIS Physical Function was significantly lower for patients with severe cervical deformity.

What are the major drivers of outcomes in cervical deformity surgery?

Background Context:

Cervical deformity (CD) correction is becoming more challenging and complex. Understanding the factors that drive optimal outcomes has been understudied in CD corrective surgery.

Purpose:

The purpose of the study was to weight baseline (BL) factors on impact upon outcomes following CD surgery.

Study Design Setting:

This was a retrospective review of a single-center database.

Patient Sample:

The sample size of the study was 61 cervical patients.

Outcome Measures:

Two outcomes were measured: “Improved outcome (IO)”: (1) radiographic improvement: “nondeformed” Schwab pelvic tilt (PT)/sagittal vertical axis (SVA) and Ames cervical sagittal vertical axis (cSVA)/T1 Slope – cervical lordosis (TSCL); (2) clinical: MCID Euro-QOL 5 Dimension (EQ5D), Neck Disability Index (NDI), or improvement in modified Japanese Orthopedic Association (mJOA) scale modifier; and (3) complications/reoperation: no reoperation or major complications and “poor outcome” (PO): (1) radiographic deterioration: “moderate” or “severely” deformed Schwab SVA/PT and Ames cSVA/TS-CL; (2) clinical: not meeting MCID EQ5D and NDI worsening in mJOA modifier; and (3) complications/reoperation: reoperation or complications.

Materials and Methods:

CD patients included full BL and 1-year (1Y) radiographic measures and Health related quality of life (HRQLs) questionnaires. Patients who underwent a reoperation for infection were excluded. Patients were categorized by IO, PO, or not. Random forest assessed ratios of predictors for IO and PO. Categorical regression models predicted how BL regional deformity (Ames cSVA, TS-CL, and horizontal gaze), BL global deformity (Schwab PI-LL, SVA, and PT), regional/global change (BL to 1Y), BL disability (mJOA score), and BL pain/function impact outcomes.

Results:

Sixty-one patients were included in the study (55.8 years, 54.1% of females). Surgical approach included 18.3% anterior, 51.7% posterior, and 30% combined. The average number of levels fused for the cohort was 7.7. Mean operative time was 823 min, and estimated blood loss (EBL): 1037ccs. At 1Y, 24.6% had an IO and 9.8% had PO. Random forest analysis showed the top five individual factors associated with an IO: BL maximum kyphosis, maximum lordosis, C0–C2, L4 pelvic angle, and NSR back pain (80% radiographic, 20% clinical). Categorical IO regression model (R² = 0.328, P = 0.007) showed low BL regional deformity (β = ‒0.082), low BL global deformity (β = ‒0.099), global improvement (β = ‒0.532), regional improvement (β = ‒0.230), low BL disability (β = ‒0.100), and low BL NDI (β = ‒0.024). Random forest demonstrated the top five individual BL factors associated with PO, 80% were radiographic: BL CL apex, DJK angle, cervical lordosis, T1 slope, and NSR neck pain. Categorical PO regression model (R² = 0.306, P = 0.012) showed high BL regional deformity (β = ‒0.108), high BL global deformity (β = ‒0.255), global decline (β = ‒0.272), regional decline (β = 0.443), BL disability (β = −‒0.164), BL and severe NDI (>69) (β = ‒0.181).

Conclusions:

Categorical weight demonstrated radiographic as the strongest predictor of both improved (global alignment) and PO (regional deformity/deterioration). Radiographic factors carry the most weight in determining an improved or PO, and can be ultimately utilized in preoperative planning and surgical decision-making to optimize outcomes.

What are the major drivers of outcomes in cervical deformity surgery?

Background Context:

Cervical deformity (CD) correction is becoming more challenging and complex. Understanding the factors that drive optimal outcomes has been understudied in CD correction surgery.

Purpose:

The purpose of this study is to assess the factors associated with improved outcomes (IO) following CD surgery.

Study Design Setting:

Retrospective review of a single-center database.

Patient Sample:

Sixty-one patients with CD.

Outcome Measures:

The primary outcomes measured were radiographic and clinical “IO” or “poor outcome” (PO). Radiographic IO or PO was assessed utilizing Schwab pelvic tilt (PT)/sagittal vertical axis (SVA), and Ames cervical SVA (cSVA)/TS-CL. Clinical IO or PO was assessed using MCID EQ5D, Neck Disability Index (NDI), and/or improvement in Modified Japanese Orthopedic Association Scale (mJOA) modifier. The secondary outcomes assessed were complication and reoperation rates.

Materials and Methods:

CD patients with data available on baseline (BL) and 1-year (1Y) radiographic measures and health-related quality of life s were included in our study. Patients with reoperations for infection were excluded. Patients were categorized by IO, PO, or not. IO was defined as “nondeformed” radiographic measures as well as improved clinical outcomes. PO was defined as “moderate or severe deformed” radiographic measures as well as worsening clinical outcome measures. Random forest assessed ratios of predictors for IO and PO. The categorical regression models were utilized to predict BL regional deformity (Ames cSVA, TS-CL, horizontal gaze), BL global deformity (Schwab PI-LL, SVA, PT), regional/global change (BL to 1Y), BL disability (mJOA score), and BL pain/function impact outcomes.

Results:

Sixty-one patients met inclusion criteria for our study (mean age of 55.8 years with 54.1% female). The most common surgical approaches were as follows: 18.3% anterior, 51.7% posterior, and 30% combined. Average number of levels fused was 7.7. The mean operative time was 823 min and mean estimated blood loss was 1037 ml. At 1 year, 24.6% of patients were found to have an IO and 9.8% to have a PO. Random forest analysis showed the top 5 individual factors associated with an “IO” were: BL Maximum Kyphosis, Maximum Lordosis, C0-C2 Angle, L4-Pelvic Angle, and NSR Back Pain (80% radiographic, 20% clinical). Categorical IO regression model (R² = 0.328, P = 0.007) found following factors to be significant: low BL regional deformity (β = ‒0.082), low BL global deformity (β = ‒0.099), global improve (β = 0.532), regional improve (β = 0.230), low BL disability (β = 0.100), and low BL NDI (β = 0.024). Random forest found the top 5 individual BL factors associated with “PO” (80% were radiographic): BL CL Apex, DJK angle, cervical lordosis, T1 slope, and NSR neck pain. Categorical PO regression model (R² = 0.306, P = 0.012) found following factors to be significant: high BL regional deformity (β = ‒0.108), high BL global deformity (β = ‒0.255), global decline (β = 0.272), regional decline (β = 0.443), BL disability (β = ‒0.164), and BL severe NDI (>69) (β = 0.181).

Conclusions:

The categorical weight demonstrated radiographic as the strongest predictor of both improved (global alignment) and PO (regional deformity/deterioration). Radiographic factors carry the most weight in determining an improved or PO and can be ultimately utilized in preoperative planning and surgical decision-making to optimize the outcomes.

The impact of postoperative neurologic complications on recovery kinetics in cervical deformity surgery

Objective:

The objective of the study is to investigate which neurologic complications affect clinical outcomes the most following cervical deformity (CD) surgery.

Methods:

CD patients (C2-C7 Cobb >10°, CL >10°, cSVA >4 cm or chin-brow vertical angle >25°) >18 years with follow-up surgical and health-related quality of life (HRQL) data were included. Descriptive analyses assessed demographics. Neurologic complications assessed were C5 motor deficit, central neurodeficit, nerve root motor deficits, nerve sensory deficits, radiculopathy, and spinal cord deficits. Neurologic complications were classified as major or minor, then: intraoperative, before discharge, before 30 days, before 90 days, and after 90 days. HRQL outcomes were assessed at 3 months, 6 months, and 1 year. Integrated health state (IHS) for the neck disability index (NDI), EQ5D, and modified Japanese Orthopaedic Association (mJOA) were assessed using all follow-up time points. A subanalysis assessed IHS outcomes for patients with 2Y follow-up.

Results:

153 operative CD patients were included. Baseline characteristics: 61 years old, 63% female, body mass index 29.7, operative time 531.6 ± 275.5, estimated blood loss 924.2 ± 729.5, 49% posterior approach, 18% anterior approach, 33% combined. 18% of patients experienced a total of 28 neurologic complications in the postoperative period (15 major). There were 7 radiculopathy, 6 motor deficits, 6 sensory deficits, 5 C5 motor deficits, 2 central neurodeficits, and 2 spinal cord deficits. 11.2% of patients experienced neurologic complications before 30 days (7 major) and 15% before 90 days (12 major). 12% of neurocomplication patients went on to have revision surgery within 6 months and 18% within 2 years. Neurologic complication patients had worse mJOA IHS scores at 1Y but no significant differences between NDI and EQ5D (0.003 vs. 0.873, 0.458). When assessing individual complications, central neurologic deficits and spinal cord deficit patients had the worst outcomes at 1Y (2.6 and 1.8 times worse NDI scores, P = 0.04, no improvement in EQ5D, 8% decrease in EQ5D). Patients with sensory deficits had the best NDI and EQ5D outcomes at 1Y (31% decrease in NDI, 8% increase in EQ5D). In a subanalysis, neurologic patients trended toward worse NDI and mJOA IHS outcomes (P = 0.263, 0.163).

Conclusions:

18% of patients undergoing CD surgery experienced a neurologic complication, with 15% within 3 months. Patients who experienced any neurologic complication had worse mJOA recovery kinetics by 1 year and trended toward worse recovery at 2 years. Of the neurologic complications, central neurologic deficits and spinal cord deficits were the most detrimental.