Predicting the combined occurrence of poor clinical and radiographic outcomes following cervical deformity corrective surgery

Laminectomy and fusion better maintains horizontal gaze than laminoplasty in cervical spondylotic myelopathy

Background

Laminectomy and fusion (LF) and laminoplasty (LP) are common treatments for cervical spondylotic myelopathy and myeloradiculopathy. While both procedures show similar clinical improvement, LF requires bony fusion while LP offers motion preservation. Cervical sagittal alignment and horizontal gaze maintenance are key outcome measures, but their comparative effects between LF and LP remain unclear. This study evaluated postoperative horizontal gaze and cervical sagittal alignment in patients undergoing either procedure.

Methods

In this retrospective cohort study at 2 academic centers, patients underwent either LF or LP. Pre/postoperative cervical sagittal alignment parameters were collected, including C2-7 lordosis, C2-7 SVA, Occiput-C2 angle, and T1-slope. The McGregor slope measured horizontal gaze, with 8° flexion to 13° extension as normal range. Primary outcome was horizontal gaze maintenance at minimum 1-year follow-up. Secondary outcomes included changes in cervical spine alignment parameters.

Results

Sixty-four patients (30 LF, 34 LP) completed minimum 1-year follow-up. Pre/postoperative sagittal alignment measures showed no significant differences between groups. Within cohorts, LP increased C2-7 sagittal vertical axis (29.1-37.6 mm, p=.04) while LF decreased C2-7 lordosis (11.5°-5.00°, p=.04). Postoperatively, LF showed significantly more optimally aligned patients (90.0%) versus LP (57.8%) (p<.01). Multivariate analysis indicated LP predicted postoperative horizontal gaze malalignment (OR 13.90 [2.10-286.62], p=.022).

Conclusions

While both procedures yielded comparable cervical sagittal alignment outcomes, LF demonstrated superior maintenance of horizontal gaze. These findings suggest that laminectomy and fusion may preserve horizontal gaze better than laminoplasty.Level of Evidence: III.

Perseverance of Optimal Realignment is Associated With Improved Cost-utility in Adult Cervical Deformity Surgery

BACKGROUND

Early-term complications may not predict long-term success after adult cervical deformity (ACD) correction.

OBJECTIVE

Evaluate whether optimal realignment results in similar rates of perioperative complications but achieves longer-term cost-utility.

STUDY DESIGN

Retrospective cohort study.

METHODS

ACD patients with 2-year data included. Outcomes: distal junctional failure (DJF), good clinical outcome (GCO):[Meeting 2 of 3: (1) NDI>20 or meeting MCID, (2) mJOA≥14, (3)NRS-Neck improved≥2]. Ideal Outcome defined as GCO without DJF or reoperation. Patient groups were stratified by correction to 'Optimal radiographic outcome', defined by cSVA 9 (<40 mm) AND TS-CL (<15 deg) upon correction. Cost calculated by CMS.com definitions, and cost-per-QALY was calculated by converting NDI to SF-6D. Multivariable analysis controlling for age, baseline T1-slope, cSVA, disability, and frailty, was used to assess complication rates, clinical outcomes, and cost-utility based on meeting optimal radiographic outcome.

RESULTS

One hundred forty-six patients included: 52 optimal radiographic realignment (O) and 94 not optimal (NO). NO group presented with higher cSVA and T1-slope. Adjusted analysis showed O group suffered similar 90-day complications (P>0.8), but less DJK, DJF (0% vs. 18%; P<0.001) and reoperations (18% vs. 35%; P=0.02). Patients meeting optimal radiographic criteria more often met Ideal outcome [odds ratio: 2.2, (1.1-4.8); P=0.03]. Despite no differences in overall cost, O group saw greater clinical improvement, translating to a better cost-utility [mean difference: $91,000, ($49,000-$132,000); P<0.001].

CONCLUSION

Despite similar perioperative courses, patients optimally realigned experienced less junctional failure, leading to better cost-utility compared with those sub-optimally realigned. Perioperative complication risk should not necessarily preclude optimal surgical intervention, and policy efforts might better focus on long-term outcome measures in adult cervical deformity surgery.

LEVEL OF EVIDENCE

Level III.

Despite a Multifactorial Etiology, Rates of Distal Junctional Kyphosis After Adult Cervical Deformity Corrective Surgery Can be Dramatically Diminished by Optimizing Age Specific Radiographic Improvement

STUDY DESIGN

Retrospective cohort study of a prospectively collected single-center database.

OBJECTIVE

Distal Junctional Kyphosis (DJK) is one of the most common complications in adult cervical deformity (ACD) correction. The utility of radiographic alignment alone in predicting and minimizing DJK occurrence warrants further study. To investigate the impact of post-operative radiographic alignment on development of DJK in ACD patients.

METHODS

ACD patients (≥18 yrs) with complete baseline (BL) and two-year (2Y) radiographic data were included. DJF was defined as DJK greater than 15° (Passias et al) or DJK with reop. Multivariable logistic regression (MVA) identified 3-month predictors of DJK. Conditional inference tree (CIT) machine learning analysis determined threshold cutoffs. Radiographic predictors were combined in a model to determine predictive value using area under the curve (AUC) methodology. "Match" refers to ideal age-adjusted alignment.

RESULTS

140 cervical deformity patients met inclusion criteria (61.3 yrs, 67% F, BMI: 29 kg/m2, CCI: 0.96 ± 1.3). Surgically, 51.3% had osteotomies, 47.1% had a posterior approach, 34.5% combined approach, 18.5% anterior approach, with an average 7.6 ± 3.8 levels fused and EBL of 824 mL. Overall, 33 patients (23.6%) developed DJK, and 11 patients (9%) developed DJF. MVA controlling for age, and baseline deformity, followed by CIT found 3M cSVA <3.7 cm (OR: .2, 95% CI:.06-.6), and TK T4-T12 <50 (OR:.17, 95% CI:.05-.5, both P < .05) were significant predictors of a lower likelihood of DJK. Receiver operator curve AUC using age, T1S match, TS-CL match, LL-TK match, cSVA <3.7 cm, and T4-T12 <50 predicted DJK with an AUC of .91 for DJK by 2Y, and .88 for DJF by 2Y.

CONCLUSION

These findings suggest post-operative radiographic alignment is strongly associated with distal junctional kyphosis. When utilizing age-adjusted realignment in addition to newly developed thresholds, a suggested post-operative cSVA target of 3.7 cm and thoracic kyphosis less than 50, it is possible to substantially reduce the occurrence of distal junctional kyphosis and distal junctional failure.

Expectations of clinical improvement following corrective surgery for adult cervical deformity based on functional disability at presentation

PURPOSE

To assess impact of baseline disability on HRQL outcomes.

METHODS

CD patients with baseline (BL) and 2 year (2Y) data included, and ranked into quartiles by baseline NDI, from lowest/best score (Q1) to highest/worst score (Q4). Means comparison tests analyzed differences between quartiles. ANCOVA and logistic regressions assessed differences in outcomes while accounting for covariates (BL deformity, comorbidities, HRQLs, surgical details and complications).

RESULTS

One hundred and sixteen patients met inclusion (Age:60.97 ± 10.45 years, BMI: 28.73 ± 7.59 kg/m2, CCI: 0.94 ± 1.31). The cohort mean cSVA was 38.54 ± 19.43 mm and TS-CL: 37.34 ± 19.73. Mean BL NDI by quartile was: Q1: 25.04 ± 8.19, Q2: 41.61 ± 2.77, Q3: 53.31 ± 4.32, and Q4: 69.52 ± 8.35. Q2 demonstrated greatest improvement in NRS Neck at 2Y (-3.93), compared to Q3 (-1.61, p = .032) and Q4 (-1.41, p = .015). Q2 demonstrated greater improvement in NRS Back (-1.71), compared to Q4 (+ 0.84, p = .010). Q2 met MCID in NRS Neck at the highest rates (69.9%), especially compared to Q4 (30.3%), p = .039. Q2 had the greatest improvement in EQ-5D (+ 0.082), compared to Q1 (+ 0.073), Q3 (+ 0.022), and Q4 (+ 0.014), p = .034. Q2 also had the greatest mJOA improvement (+ 1.517), p = .042.

CONCLUSIONS

Patients in Q2, with mean BL NDI of 42, consistently demonstrated the greatest improvement in HRQLs whereas those in Q4, (NDI 70), saw the least. BL NDI between 39 and 44 may represent a disability "Sweet Spot," within which operative intervention maximizes patient-reported outcomes. Furthermore, delaying intervention until patients are severely disabled, beyond an NDI of 61, may limit the benefits of surgery.

Patient-specific Cervical Deformity Corrections With Consideration of Associated Risk: Establishment of Risk Benefit Thresholds for Invasiveness Based on Deformity and Frailty Severity

STUDY DESIGN/SETTING

This was a retrospective cohort study.

BACKGROUND

Little is known of the intersection between surgical invasiveness, cervical deformity (CD) severity, and frailty.

OBJECTIVE

The aim of this study was to investigate the outcomes of CD surgery by invasiveness, frailty status, and baseline magnitude of deformity.

METHODS

This study included CD patients with 1-year follow-up. Patients stratified in high deformity if severe in the following criteria: T1 slope minus cervical lordosis, McGregor's slope, C2-C7, C2-T3, and C2 slope. Frailty scores categorized patients into not frail and frail. Patients are categorized by frailty and deformity (not frail/low deformity; not frail/high deformity; frail/low deformity; frail/high deformity). Logistic regression assessed increasing invasiveness and outcomes [distal junctional failure (DJF), reoperation]. Within frailty/deformity groups, decision tree analysis assessed thresholds for an invasiveness cutoff above which experiencing a reoperation, DJF or not achieving Good Clinical Outcome was more likely.

RESULTS

A total of 115 patients were included. Frailty/deformity groups: 27% not frail/low deformity, 27% not frail/high deformity, 23.5% frail/low deformity, and 22.5% frail/high deformity. Logistic regression analysis found increasing invasiveness and occurrence of DJF [odds ratio (OR): 1.03, 95% CI: 1.01-1.05, P =0.002], and invasiveness increased with deformity severity ( P <0.05). Not frail/low deformity patients more often met Optimal Outcome with an invasiveness index <63 (OR: 27.2, 95% CI: 2.7-272.8, P =0.005). An invasiveness index <54 for the frail/low deformity group led to a higher likelihood of meeting the Optimal Outcome (OR: 9.6, 95% CI: 1.5-62.2, P =0.018). For the frail/high deformity group, patients with a score <63 had a higher likelihood of achieving Optimal Outcome (OR: 4.8, 95% CI: 1.1-25.8, P =0.033). There was no significant cutoff of invasiveness for the not frail/high deformity group.

CONCLUSIONS

Our study correlated increased invasiveness in CD surgery to the risk of DJF, reoperation, and poor clinical success. The thresholds derived for deformity severity and frailty may enable surgeons to individualize the invasiveness of their procedures during surgical planning to account for the heightened risk of adverse events and minimize unfavorable outcomes.

Is It Necessary to Cross the Cervicothoracic Junction in Posterior Cervical Decompression and Fusion for Multilevel Degenerative Cervical Spine Disease? A Systematic Review and Meta-Analysis

BACKGROUND

Posterior cervical decompression and fusion (PCF) is a common procedure for treating patients with multilevel degenerative cervical spine disease. The selection of lower instrumented vertebra (LIV) relative to the cervicothoracic junction (CTJ) remains controversial. This study aimed to compare the outcomes of PCF construct terminating at the lower cervical spine and crossing the CTJ.

METHODS

A comprehensive literature search was performed for relevant studies in the PubMed, EMBASE, Web of Science, and Cochrane Library database. Complications, rate of reoperation, surgical data, patient-reported outcomes (PROs), and radiographic outcomes were compared between PCF construct terminating at or above C7 (cervical group) and at or below T1 (thoracic group) in patients with multilevel degenerative cervical spine disease. A subgroup analysis based on surgical techniques and indications was performed.

RESULTS

Fifteen retrospective cohort studies comprising 2071 patients (1163 in the cervical group and 908 in the thoracic group) were included. The cervical group was associated with a lower incidence of wound-related complications (RR, 0.58; 95% CI 0.36 to 0.92, p = 0.022; 831 patients in cervical group vs. 692 patients in thoracic group), a lower reoperation rate for wound-related complications (RR, 0.55; 95% CI 0.32 to 0.96, p = 0.034; 768 vs. 624 patients), and less neck pain at the final follow-up (WMD, -0.58; 95% CI -0.93 to -0.23, p = 0.001; 327 vs. 268 patients). However the cervical group also developed a higher incidence of overall adjacent segment disease (ASD, including distal ASD and proximal ASD) (RR, 1.87; 95% CI 1.27 to 2.76, p = 0.001; 1079 vs. 860 patients), distal ASD (RR, 2.18; 95% CI 1.36 to 3.51, p = 0.001; 642 vs. 555 patients), overall hardware failure (including hardware failure of LIV and hardware failure occurring at other instrumented vertebra) (RR, 1.48; 95% CI 1.02 to 2.15, p = 0.040; 614 vs. 451 patients), and hardware failure of LIV (RR, 1.89; 95% CI 1.21 to 2.95, p = 0.005; 380 vs. 339 patients). The operating time was reasonably shorter (WMD, -43.47; 95% CI -59.42 to -27.52, p < 0.001; 611 vs. 570 patients) and the estimated blood loss was lower (WMD, -143.77; 95% CI -185.90 to -101.63, p < 0.001; 721 vs. 740 patients) when the PCF construct did not cross the CTJ.

CONCLUSIONS

PCF construct crossing the CTJ was associated with a lower incidence of ASD and hardware failure but a higher incidence of wound-related complications and a small increase in qualitative neck pain, without difference in neck disability on the NDI. Based on the subgroup analysis for surgical techniques and indications, prophylactic crossing of the CTJ should be considered for patients with concurrent instability, ossification, deformity, or a combination of anterior approach surgeries as well. However, long-term follow-up outcomes and patient selection-related factors such as bone quality, frailty, and nutrition status should be addressed in further studies.

Clinical and surgical results related to anterior-only multilevel cervical decompression and instrumented fusion for degenerative disease

Introduction

Anterior-only multilevel cervical decompression and fusion surgery (AMCS) on 3-5-levels is challenging due to potential complications. Also, outcome predictors after AMCS are poorly understood.

Research Question

We hypothesize that in patients with at most mild/moderate cervical kyphosis (CK) of the cervical spine, restoration of cervical lordosis (CL) positively influences clinical outcomes.

Methods

Analysis of consecutive patients presenting with symptomatic degenerative cervical disease or non-union undergoing AMCS. We measured CL from C2 to C7, Cobb angle of fused levels (fusion angle, FA), C7-Slope, and sagittal vertical axis C2-7 (cSVA, stratified into ≤4cm∖>4cm). Patients with excellent outcome were grouped in BEST-outcomes and with moderate/poor outcomes in WORST-outcomes.

Results

We included 244 patients. Fifty-four percent had 3-, 39% 4-level and 7% had 5-level fusion. At mean follow-up of 26 months, 41% of patients achieved BEST-outcome and 23% WORST-outcome. Complications and reoperation rates did not significantly differ. Non-union significantly influenced outcomes. The number of patients with non-union was significantly higher in patients with a preoperative cSVA>4cm (OR 13.1 (95%CI:1.8-96.8). Our model, based on the multivariable analysis with WORST-outcome as outcome variable showed a high accuracy (NPV=73%, PPV=77%, specificity=79%, sensitivity=71%).

Discussion and Conclusion

In 3-5-level AMCS, improvement of FA and cSVA were independent predictors of clinical outcome. Improvement of CL positively influenced clinical outcomes and rates of non-union.

Trends in Outcomes of a Prospective Consecutively Enrolled Single-Center Adult Cervical Deformity Series

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

The aim was to describe the two-year outcomes for patients undergoing surgical correction of cervical deformity (CD).

BACKGROUND

Adult CD has been shown to compromise health-related quality of life. While advances in spinal realignment have shown promising short-term clinical results in this parameter, the long-term outcomes of CD corrective surgery remain unclear.

MATERIALS AND METHODS

Operative CD patients >18 years with two-year (2Y) health-related quality of life/radiographic data were included. Improvement in radiographic, neurologic, and health-related quality of life outcomes were reported. Patients with a prior cervical fusion and patients with the greatest and smallest change based on Neck Disability Index (NDI), numeric rating scale (NRS) neck, modified Japanese Orthopaedic Association (mJOA) were compared using multivariable analysis controlling for age, and frailty, and invasiveness.

RESULTS

One hundred and fifty-eight patients were included in this study. By 2Y, 96.3% of patients improved in Ames cervical sagittal vertical axis modifier, 34.2% in T1 slope minus cervical lordosis (TS-CL), 42.0% in horizontal gaze modifier, and 40.9% in SVA modifier. In addition, 65.5% of patients improved in Passias CL modifier, 53.3% in TS-CL modifier, 100% in C2-T3 modifier, 88.9% in C2S modifier, and 81.0% in MGS modifier severity by 2Y. The cohort significantly improved from baseline to 2Y in NDI, NRS Neck, and mJOA, all P <0.05. 59.3% of patients met minimal clinically important difference for NDI, 62.3% for NRS Neck, and 37.3% for mJOA. Ninety-seven patients presented with at least one neurologic deficit at baseline and 63.9% no longer reported that deficit at follow-up. There were 45 (34.6%) cases of distal junctional kyphosis (DJK) (∆DJKA>10° between lower instrumented vertebra and lower instrumented vertebra-2), of which 17 were distal junctional failure (distal junctional failure-DJK requiring reoperation). Patients with the greatest beneficial change were less likely to have had a complication in the two-year follow-up period.

CONCLUSION

Correction of CD results in notable clinical and radiographic improvement with most patients achieving favorable outcomes after two years. However, complications including DJK or failure remain prevalent.

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.

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.

When can we expect global sagittal alignment to reach a stable value following cervical deformity surgery?

OBJECTIVE

Cervical deformity (CD) is a complex condition with a clear impact on patient quality of life, which can be improved with surgical treatment. Previous study following thoracolumbar surgery demonstrated a spontaneous and maintained improvement in cervical alignment following lumbar pedicle subtraction osteotomy (PSO). In this study the authors aimed to investigate the complementary questions of whether cervical alignment induces a change in global alignment and whether this change stabilizes over time.

METHODS

To analyze spontaneous changes, this study included only patients with at least 5 levels remaining unfused following surgery. After data were obtained for the entire cohort, repeated-measures analyses were conducted between preoperative baseline and 3-month and 1-year follow-ups with a post hoc analysis and Bonferroni correction. A subanalysis of patients with 2-year follow-up was performed.

RESULTS

One-year follow-up data were available for 121 of 168 patients (72%), and 89 patients had at least 5 levels remaining unfused following surgery. Preoperatively there was a moderate anterior cervical alignment (C2-7, -7.7° [kyphosis]; T1 slope minus cervical lordosis, 37.1°; cervical sagittal vertebral axis [cSVA], 37 mm) combined with a posterior global alignment (SVA, -8 mm) with lumbar hyperextension (pelvic incidence [PI] minus lumbar lordosis [LL] mismatch [PI-LL], -0.6°). Patients underwent a significant correction of the cervical alignment (median ΔC2-7, 13.6°). Simultaneously, PI-LL, T1 pelvic angle (TPA), and SVA increased significantly (all p < 0.05) between baseline and 3-month and 1-year follow-ups. Post hoc analysis demonstrated that all of the changes occurred between baseline and 3 months. Subanalysis of patients with complete 2-year follow-up demonstrated similar results, with stable postoperative thoracolumbar alignment achieved at 3 months.

CONCLUSIONS

Correction of cervical malalignment can have a significant impact on thoracolumbar regional and global alignment. Peak relaxation of compensatory mechanisms is achieved by the 3-month follow-up and tends to remain stable. Subanalysis with 2-year data further supports this finding. These findings can help to identify when the results of cervical surgery on global alignment can be best evaluated.

Surgical Strategy for the Management of Cervical Deformity Is Based on Type of Cervical Deformity

Objectives: Cervical deformity morphotypes based on type and location of deformity have previously been described. This study aimed to examine the surgical strategies implemented to treat these deformity types and identify if differences in treatment strategies impact surgical outcomes. Our hypothesis was that surgical strategies will differ based on different morphologies of cervical deformity. Methods: Adult patients enrolled in a prospective cervical deformity database were classified into four deformity types (Flatneck (FN), Focal kyphosis (FK), Cervicothoracic kyphosis (CTK) and Coronal (C)), as previously described. We analyzed group differences in demographics, preoperative symptoms, health-related quality of life scores (HRQOLs), and surgical strategies were evaluated, and postop radiographic and HROQLs at 1+ year follow up were compared. Results: 90/109 eligible patients (mean age 63.3 ± 9.2, 64% female, CCI 1.01 ± 1.36) were evaluated. Group distributions included FN = 33%, FK = 29%, CTK = 29%, and C = 9%. Significant differences were noted in the surgical approaches for the four types of deformities, with FN and FK having a high number of anterior/posterior (APSF) approaches, while CTK and C had more posterior only (PSF) approaches. For FN and FK, PSF was utilized more in cases with prior anterior surgery (70% vs. 25%). For FN group, PSF resulted in inferior neck disability index compared to those receiving APSF suggesting APSF is superior for FN types. CTK types had more three-column osteotomies (3CO) (p < 0.01) and longer fusions with the LIV below T7 (p < 0.01). There were no differences in the UIV between all deformity types (p = 0.19). All four types of deformities had significant improvement in NRS neck pain post-op (p < 0.05) with their respective surgical strategies. Conclusions: The four types of cervical deformities had different surgical strategies to achieve improvements in HRQOLs. FN and FK types were more often treated with APSF surgery, while types CTK and C were more likely to undergo PSF. CTK deformities had the highest number of 3COs. This information may provide guidelines for the successful management of cervical deformities.

Cervicothoracic Versus Proximal Thoracic Lower Instrumented Vertebra Have Comparable Radiographic and Clinical Outcomes in Adult Cervical Deformity

STUDY DESIGN

Comparative cohort study.

OBJECTIVE

Factors that influence the lower instrumented vertebra (LIV) selection in adult cervical deformity (ACD) are less reported, and outcomes in the cervicothoracic junction (CTJ) and proximal thoracic (PT) spine are unclear.

METHODS

A prospective ACD database was analyzed using the following inclusion criteria: LIV between C7 and T5, upper instrumented vertebra at C2, and at least a 1-year follow-up. Patients were divided into CTJ (LIV C7-T2) and PT groups (LIV T3-T5) based on LIV levels. Demographics, operative details, radiographic parameters, and the health-related quality of life (HRQOL) scores were compared.

RESULTS

Forty-six patients were included (mean age, 62 years), with 22 and 24 patients in the CTJ and PT groups, respectively. Demographics and surgical parameters were comparable between the groups. The PT group had a significantly higher preoperative C2-C7 sagittal vertical axis (cSVA) (46.9 mm vs 32.6 mm, P = 0.002) and T1 slope minus cervical lordosis (45.9° vs 36.0°, P = 0.042) than the CTJ group and was more likely treated with pedicle-subtraction osteotomy (33.3% vs 0%, P = 0.004). The PT group had a larger correction of cSVA (-7.7 vs 0.7 mm, P = 0.037) and reciprocal change of increased T4-T12 kyphosis (8.6° vs 0.0°, P = 0.001). Complications and reoperations were comparable. The HRQOL scores were not different preoperatively and at 1-year follow-up.

CONCLUSIONS

The selection of PT LIV in cervical deformities was more common in patients with larger baseline deformities, who were more likely to undergo pedicle-subtraction osteotomy. Despite this, the complications and HRQOL outcomes were comparable at 1-year follow-up.

Association of Spinal Alignment Correction With Patient-Reported Outcomes in Adult Cervical Deformity: Review of the Literature

Objective

Adult cervical deformity (ACD) is a debilitating spinal condition that causes significant pain, neurologic dysfunction, and functional impairment. Surgery is often performed to correct cervical alignment, but the optimal amount of correction required to improve patient-reported outcomes (PROs) are not yet well-defined.

Methods

A review of the literature was performed and Fisher's z-transformation (Zr) was used to pool the correlation coefficients between alignment parameters and PROs. The strength of correlation was defined according to the following: poor (0 < r ≤ 0.3), fair (0.3 < r ≤ 0.5), moderate (0.5 < r ≤ 0.8), and strong (0.8 < r ≤ 1).

Results

Increased C2-C7 SVA was fairly associated with increased Neck Disability Index (NDI) (pooled Zr = 0.31; 95% CI, -0.03, 0.58). Changes in TS-CL poorly correlated with NDI (pooled Zr = -0.04; 95% CI, -0.23-0.30). Increased C7-S1 was poorly associated with worse EQ-5D (pooled Zr = -0.22; 95% CI, -0.36, -0.06). Correction of horizontal gaze (CBVA) did not correlate with legacy metrics. mJOA correlated with C2-slope, C7-S1, and C2-S1.

Conclusion

Spinal alignment parameters variably correlated with improved HRQoL and myelopathy after corrective surgery for ACD. Further studies evaluating legacy PROs, PROMIS, and ACD specific instruments are needed for further validation.

Narrative Review of Predictive Analytics of Patient-Reported Outcomes in Adult Spinal Deformity Surgery

STUDY DESIGN

Narrative review.

OBJECTIVE

Decision making in surgery for adult spinal deformity (ASD) is complex due to the multifactorial etiology, numerous surgical options, and influence of multiple medical and psychosocial factors on patient outcomes. Predictive analytics provide computational tools to analyze large data sets and generate hypotheses regarding new data. In this review, we examine the use of predictive analytics to predict patient-reported outcomes (PROs) in ASD surgery.

METHODS

A search of PubMed, Web of Science, and Embase databases was performed to identify all potentially relevant studies up to February 1, 2020. Studies were included based on the use of predictive analytics to predict PROs in ASD.

RESULTS

Of 57 studies identified and reviewed, 7 studies were included. Multiple algorithms including supervised and unsupervised methods were used. Significant heterogeneity was observed with choice of PROs modeled including ODI, SRS22, and SF36, assessment of model accuracy, and with the model accuracy and area under the receiver operating curve values (ranging from 30% to 86% and 0.57 to 0.96, respectively). Models were built with data sets of patients ranging from 89 to 570 patients with a range of 22 to 267 variables.

CONCLUSIONS

Predictive analytics makes accurate predictions regarding PROs regarding pain, disability, and work and social function; PROs regarding satisfaction, self-image, and psychologic aspects of ASD were predicted with the lowest accuracy. Our review demonstrates a relative paucity of studies on ASD with limited databases. Future studies should include larger and more diverse databases and provide external validation of preexisting models.

Sagittal balance of the cervical spine: a systematic review and meta-analysis

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the cervical sagittal parameters between patients with cervical spine disorder and asymptomatic controls.

METHODS

Two independent authors systematically searched online databases including Pubmed, Scopus, Cochrane library, and Web of Science up to June 2020. Cervical sagittal balance parameters, such as T1 slope, cervical SVA (cSVA), and spine cranial angle (SCA), were compared between the cervical spine in healthy, symptomatic, and pre-operative participants. Where possible, we pooled data using random-effects meta-analysis, by CMA software. Heterogeneity and publication bias were assessed using the I-squared statistic and funnel plots, respectively.

RESULTS

A total of 102 studies, comprising 13,802 cases (52.7% female), were included in this meta-analysis. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Funnel plot and Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the mean (SD) values were: T1 slope (degree), 24.5 (0.98), 25.7 (0.99), 25.4 (0.34); cSVA (mm), 18.7 (1.76), 22.7 (0.66), 22.4 (0.68) for healthy population, symptomatic, and pre-operative assessment, respectively. The mean value of the SCA (degree) was 79.5 (3.55) and 75.6 (10.3) for healthy and symptomatic groups, respectively. Statistical differences were observed between the groups (all P values < 0.001).

CONCLUSION

The findings showed that the T1 slope and the cSVA were significantly lower among patients with cervical spine disorder compared to controls and higher for the SCA. Further well-conducted studies are needed to complement our findings.

A new nomenclature system for the surgical treatment of cervical spine deformity, developing, and validation of SOF system

PURPOSE

To develop and assess the reliability of new nomenclature system that systematically organizes osteotomy techniques and briefly describes the surgical approach, the surgical sequence, and the fixation technique for cervical spine deformity (CSD).

METHODS

We developed a new classification system (SOF system) for CSD surgery that describes the sequence of surgical approach (S), the grade of osteotomy (O), and the information of fixation (F) using alphanumeric codes. Twenty CSD osteotomies (8 anterior osteotomies, 12 posterior osteotomies) were included in this study to evaluate the inter- and intra-observer agreement based on operation records. Six observers performed independent evaluations of the operation records in random order. Each observer described 20 CSD surgeries using the SOF system twice (> 30 days between assessments) based on operation records to validate SOF system.

RESULTS

Overall agreement (among all six observers at the initial assessment) on the anterior and posterior osteotomy was ICC = 0.96 and ICC = 0.91, respectively. Overall agreement (repeat observations after at least 30 days) on the anterior and posterior osteotomy was ICC = 0.96 and ICC = 0.91, respectively. This data showed that both inter- and intra-observer agreement revealed 'excellent'.

CONCLUSION

This study introduces the SOF system of the CSD surgery to understand the surgical sequence, the type of osteotomy and the fixation techniques. The investigation of the inter- and intra-observer agreement revealed 'excellent agreement' for both anterior and posterior osteotomies. Thus, SOF system can provide a consistent description of the various CSD surgeries and its use will provide a common frame for CSD surgery and help communicate between surgeons.