Fusion For Adult Spinal Deformity Research Articles

553 Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adult spinal deformity: a systematic review

553 Sociodemographic variables are rarely reported in randomized controlled trials investigating posterior spinal fusion for adult spinal deformity: a systematic review

Glycemic laboratory values are associated with increased length of stay and 90-day revision risk following surgical management of adult spinal deformity

BACKGROUND CONTEXTDiabetes mellitus (DM) is a common comorbidity among patients undergoing spinal fusion for adult spinal deformity (ASD) surgery. An elevated Hemoglobin A1c (HbA1c) and elevated postoperative glucose have been shown to increase the risk of complications following spine and other orthopedic surgeries; however, data is limited for ASD. PURPOSETo investigate glycemic control and ASD surgery to inform surgical decision making, medical optimization, and patient education. STUDY DESIGN/SETTINGRetrospective cohort. PATIENT SAMPLETotal of 106 adult patients undergoing surgical correction for ASD with an HbA1c drawn within 6 months preoperatively or 2 weeks postoperatively and valid plasma glucose levels throughout postoperative hospital stay. OUTCOME MEASURESLength of stay, 90-day wound complication, 90-day readmission, 90-day revision. METHODSAll patients undergoing spinal fusion of seven or more levels between 2021 and 2023 at two large academic medical centers were identified using institutional data acquisition software. Medical charts were then manually reviewed to obtain and confirm demographic, laboratory, and surgical characteristics and outcomes. Laboratory characteristics included preoperative HbA1c, mean postoperative glucose (PG), and maximum PG. Surgical characteristics and outcomes included procedure time, estimated blood loss (EBL), length of inpatient stay (LOS), transfusion requirement, 90-day complications, 90-day revision, and 90-day readmission. Bivariate analysis was performed followed by simple and multiple regression analysis. Odds ratios were established relative to the laboratory threshold values informed by receiver operating characteristics. RESULTSOf 872 original procedures identified, 106 patients (12.2%) were adults with preoperative HbA1c and postoperative plasma glucose measurements who underwent surgery for a diagnosis of ASD. Median patient age was 67 years (IQR 59–72 years), 59 (55.7%) were female, and 96 (90.6%) were of Caucasian race. Median LOS was 7 days (IQR 5–10 years) and median HbA1c was 5.9% (IQR 5.3%–6.5%). Higher preoperative HbA1c was correlated with increased LOS (R=0.22, p=.023). The odds ratio for patients requiring extended LOS was 2.49 (95% CI 1.06–5.86, p=.034) for those with HbA1c ≥6.3%. Multiple regression analysis of LOS identified HbA1c [B= 1.51 (95% CI 0.32–2.70), p=.013] as a positive predictor of LOS and mean PG [B= −0.05 (95% CI −0.10 to (−0.01)), p=.019] as a weakly negative predictor of LOS. Upon simple logistic regression, the odds ratio for 90-day revision was 1.81 (95% CI 1.02–3.19, p=.042) for every unit increase in HbA1c. Patients with mean PG ≥165 mg/dL [OR=5.76 (95% CI 1.28–26.01), p=.024] were at increased risk for 90-day revision. Glycemic laboratory values do not seem to predict 90-day wound complications or 90-day readmission following surgery for ASD. CONCLUSIONElevated preoperative HbA1c is associated with increased LOS and risk for revision within 90 days of ASD surgery. Postoperative hyperglycemia is also associated with increased 90-day revision risk. To our knowledge, this study is the first to evaluate HbA1c and outcomes following ASD surgery. These findings can be leveraged to inform preoperative medical optimization and highlight the importance of glycemic control in ASD patients undergoing corrective surgical intervention.

Utility of Risk Analysis Index for Assessing Morbidity in Patients Undergoing Posterior Spinal Fusion for Adult Spinal Deformity

This study investigates the predictive values of the Risk Analysis Index (RAI), the modified 5-item Frailty Index (mFI-5), and advanced age for predicting 30-day extended length of stay (LOS), 30-day complications, and readmissions in patients undergoing posterior spinal fusion (PSF) for adult spinal deformity (ASD). A retrospective cohort study was performed using the 2012-2021 American College of Surgeons National Surgical Quality Improvement Program database. Adults undergoing PSF for ASD were identified using Current Procedural Terminology and International Classification of Diseases codes. Using receiver operating characteristic and multivariable analyses, we compared the discriminative thresholds and independent associations of RAI, mFI-5, and greater patient age for extended LOS, 30-day complications, and readmissions. In this cohort of 3814 patients, RAI identified 90.7% as Robust, 6.0% as Normal, and 3.3% as Frail/Very frail, while mFI-5 classified 47.1% as Robust, 37.5% as Normal, and 15.3% as Frail/Very frail. Multivariable analysis revealed both RAI and mFI-5 as significant predictors of extended LOS for Normal (RAI: P < 0.001; mFI-5: P=0.013) and Frail/Very frail patients (RAI: P < 0.001; mFI-5: P= 0.003). Additionally, RAI was a significant predictor of 30-day complication risk for Normal patients (P= 0.005). Furthermore, mFI-5 was a significant predictor of 30-day readmission among Frail/Very frail patients (P=0.002). This study suggests that the utility of RAI and mFI-5 in predicting extended LOS patients undergoing PSF for ASD. RAI was found to be superior to mFI-5 for predicting 30-day readmissions, while mF-5 was greater for 30-day complications. These findings highlight the need for future studies to identify optimal methods in incorporating frailty assessments into preoperative surgical planning and patient discussions.

Early clinical outcomes and medical complications following long segment fusion for adult spinal deformity with and without three column osteotomy

BackgroundSurgical treatment of adult spinal deformity (ASD) commonly involves long-segment fusion with or without three column osteotomies (3CO) to provide satisfactory correction of sagittal and coronal balance. While some clinical studies have implicated 3CO as a driver of high surgical complication rates, these prior investigations are limited by small sample size. Herein, we compare early outcomes and adverse events in patients undergoing long segment posterior spinal fusion for ASD with and without 3CO. MethodsA multicenter administrative database was queried for patients undergoing elective posterior spinal fusion for ASD. Patients were stratified based upon long segment fusion with and without 3CO. Preoperative patient demographics, procedural characteristics, hospitalization events, and postoperative complication rates were evaluated. Student's t-test and Fisher's exact test were utilized where appropriate to compare differences between the two groups for continuous and categorical variables. Results340 cases met the inclusion criteria, of which 156 involved 3CO. Patients who required 3CO had a lower rate of preoperative diabetes (22.3 % vs 10.3 %, p = 0.003), higher rates of non-home discharge (26.2 % vs 57.1 %, p < 0.001), longer operation time (245.62 ± 9.45 vs. 434.40 ± 11.65, p < 0.001), and longer length of stay (4.17 ± 0.66 vs. 7.76 ± 0.83, p < 0.001). In terms of complications, 3CO patients had higher rates of deep surgical site infection (0 % vs 3.2 %, p = 0.02), reintubation (0 % vs 4.5 %, p = 0.004), inability to wean off ventilator (0 % vs 2.6 %, p = 0.04), and perioperative blood transfusion (20.1 % vs 76.3 %, p < 0.001). ConclusionsIn this retrospective analysis, posterior 3CO was frequently undertaken but associated with higher risk for postoperative adverse events following spinal deformity correction.

P283. Primary fragility fracture history predicts opioid dependence at 2-year follow-up in patients undergoing thoracolumbar fusion for adult spinal deformity

P283. Primary fragility fracture history predicts opioid dependence at 2-year follow-up in patients undergoing thoracolumbar fusion for adult spinal deformity

Novel method of iliac accessory rods for rod fracture prevention in adult deformity surgery: a case series of 82 patients with outcomes and complications.

Primary rod fracture after surgery for adult spinal deformity (ASD) is a leading cause of revision, with recent prospective multicenter fracture rates reported at 11%-14% by 2 years. Consequently, the addition of supplemental rods has been explored to reduce fractures. Here the authors describe their experience with a novel iliac accessory rod technique in which each accessory rod anchors to an independent iliac bolt caudally via lateral connector, and attaches to the primary rod rostrally via side-to-side connector. This retrospective, single-center case series included patients who underwent thoracolumbar/lumbar fusion for ASD between March 2019 and August 2023. Data on baseline demographics, radiographic parameters, surgical characteristics, complications, rod fracture, and revision rates were collected. Paired, 2-tailed t-tests were used to compare pre- and postoperative radiographic outcomes. Rod fracture rates were compared to prior investigations via chi-square goodness of fit testing. The technique for iliac accessory rod placement is described. The study consisted of 82 patients (mean age 66 years, 51% female, 26% with prior fusion) with a median follow-up of 2 years (IQR 28-104 weeks). A total of 50 patients (61%) had ≥ 2-year follow-up. Each surgery involved an average of 4 posterior column osteotomies and 8 segments. Iliac accessory rods were cobalt chromium and were placed bilaterally in 87% of constructs. Postoperative alignment improved significantly in the following parameters: maximum coronal Cobb angle, fractional curve, sagittal vertical axis, lumbar lordosis, thoracic kyphosis, and pelvic incidence to lumbar lordosis mismatch (p < 0.001 for all comparisons). Of 50 patients with ≥ 2-year follow-up, rod fracture occurred in 1 (2.0%), which was incidentally found and required no intervention. The present rod fracture rate was significantly lower than the authors' historically reported institutional rate of 21% for traditional dual-rod constructs, and the 11%-14% reported in recent prospective multicenter studies that used traditional and supplemental rod constructs (p < 0.05 for all comparisons). Reoperation occurred in 12 patients (14.6%); 7 (8.5%) for proximal junctional kyphosis and 5 (6.1%) for wound complication. Here the authors describe their experience with a novel iliac accessory rod technique to prevent rod fracture in patients undergoing surgery for ASD. The 2-year rod fracture rate (2.0%) in this study is significantly lower than the authors' historical dual-rod fracture rate, and other prospective multicenter investigations. Future studies with longer follow-up are needed to determine the durability of this technique.

Can We Rely on Prophylactic Two-Level Vertebral Cement Augmentation in Long-Segment Adult Spinal Deformity Surgery to Reduce the Incidence of Proximal Junctional Complications?

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results-a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)-could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.

The Optimal Patient Position on the Surgical Table for Lateral Lumbar Interbody Fusion in Adult Spinal Deformity Using Three-Dimensional Computed Tomography: A Retrospective Study

Lateral lumbar interbody fusion (LLIF) techniques have been extensively used in adult spinal deformity surgery. Preoperative knowledge of the optimal position of the patient on the surgical table is essential for a safe procedure. Therefore, this study aims to determine the optimal angle for positioning the patient on the surgical table during LLIF using three-dimensional computed tomography (3DCT). Data from 59 patients (2 males, 57 females, mean age 66.3±8.6 years) with adult spinal deformities treated by performing corrective spinal surgery were included in this observational retrospective study. Simulated fluoroscopic images were obtained using 3DCT images rotated from the reference position with the spinous process of S1 as the midline to the position with the spinous process in the center of the bilateral pedicle of T12-L5. The rotation angle of each vertebra was measured and defined as the optimal rotation angle (ORA). The angle that bisected the angle between the maximum and minimum ORA was defined as the optimal mean angle of the maximum and minimum ORA (OMA) and considered the optimal angle for the patient's position on the surgical table, as this position could minimize the rotation angle of the surgical table during surgery. A multiple regression analysis was performed to predict OMA. Multiple regression analysis revealed the following equation: OMA=1.959+(0.238×lumbar coronal Cobb angle)+(-0.208×sagittal vertical axis). When the patient is placed on the surgical table by rotating them at the OMA, the rotation of the surgical table can be reduced, ensuring a safe and efficient surgical procedure.

Sarcopenia in paraspinal muscle as a risk factor of proximal junctional kyphosis and proximal junctional failure after adult spinal deformity surgery.

The aim of this study was to identify the risk factors for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), including paraspinal muscle atrophy. Fifty-seven consecutive patients who underwent a long-instrumented fusion for adult spinal deformity (ASD) with a minimum follow-up of 2 years were included in the study. Patient, surgical, and radiological factors were evaluated. Muscle volume was measured using the muscle/vertebra ratio of the multifidus, erector spinae (ES), and psoas muscles, and muscle function was evaluated using the degree of fat infiltration at the L4-5 level. The study included 57 consecutive patients: 25 patients in the combined PJK/PJF group (13 with PJK and 12 with PJF) and 32 in the control group (without PJK or PJF). The mean time to onset of PJK and PJF was 15.7 and 1.7 months, respectively. Multivariate analysis showed that greater pre- and postoperative sagittal vertical axis was associated with the occurrence of PJK/PJF. ES muscle atrophy was more significant in the PJK/PJF group than in the control group, and more severe in the PJF than in the PJK group. This study showed that PJF occurred much earlier than PJK after ASD surgery. Paraspinal muscle atrophy was identified as a significant risk factor for PJK and PJF, especially PJF. The possibility of PJK and PJF development should be considered when long-segment fusion is planned for patients with paraspinal muscle atrophy.

Long-term Outcomes After Adult Spinal Deformity Surgery Using Lateral Interbody Fusion: Short Versus Long Fusion.

Retrospective cohort study. To investigate long-term outcomes after short or long fusion for adult spinal deformity using lateral interbody fusion. Lateral interbody fusion is commonly used in adult spinal deformity surgery. Favorable short-term outcomes have been reported, but not long-term outcomes. Lateral interbody fusion with strong ability to correct deformity may allow the selection of short fusion techniques. We retrospectively reviewed adults who underwent this surgery with a minimum of 5 years of follow-up. Short fusion with the uppermost instrumented vertebra in the lumbar spine was performed in patients without degenerative changes at the thoracolumbar junction (S-group); others underwent long fusion with the uppermost instrumented vertebra in the thoracic spine (L-group). We assessed radiographic and clinical outcomes. Short fusion was performed in 29 of 54 patients. One patient per group required revision surgery. Of the remainder, with similar preoperative characteristics and deformity correction between groups, correction loss (pelvic incidence-lumbar lordosis, P =0.003; pelvic tilt, P =0.005; sagittal vertical axis, P ˂0.001) occurred within 2 years postoperatively in the S-group, and sagittal vertical axis continued to increase until the 5-year follow-up ( P =0.021). Although there was a significant change in Oswestry disability index in the S-group ( P =0.031) and self-image of Scoliosis Research Society 22r score in both groups ( P =0.045 and 0.02) from 2- to 5-year follow-up, minimum clinically important differences were not reached. At 5-year follow-up, there was a significant difference in Oswestry Disability Index ( P =0.013) and Scoliosis Research Society 22r scores (function: P =0.028; pain: P =0.003; subtotal: P =0.006) between the groups, but satisfaction scores were comparable and Oswestry Disability Index score (29.8%) in the S-group indicated moderate disability. Health-related quality of life was maintained between 2- and 5-year follow-up in both groups. Short fusion may be an option for patients without degenerative changes at the thoracolumbar junction. III.

Effectiveness of a two-stage posterior-anterior–posterior surgery using subcutaneously preserved autologous bone grafts for adult spinal deformity: a retrospective observational study

BackgroundTo achieve optimal correction of rigid kyphoscoliosis, we developed a novel two-stage posterior-anterior–posterior (PAP) surgery using subcutaneously preserved autologous bone grafts. This study aimed to investigate the effectiveness of two-stage PAP surgery versus single-stage anterior–posterior (AP) surgery.MethodsThis was a retrospective analysis of patients undergoing combined anterior–posterior long-level fusion for adult spinal deformity (ASD) with a minimum 2-year follow-up. The indications for two-stage PAP surgery were rigid thoracolumbar deformity associated with hypertrophic facet arthritis and/or a large pelvic incidence–lumbar lordosis mismatch of > 25°. In the first stage of PAP surgery, pedicle screw insertion and multilevel Ponte osteotomies were performed. The resected local bone was embedded under sutured fascia. One week later, the embedded bone was retrieved in the right lateral position and used as an autograft for lateral lumbar interbody fusion. Final deformity correction was performed in the prone position.ResultsFrom January 2018 to April 2021, 12 and 16 patients with ASD underwent two-stage PAP surgery (PAP group) and single-stage AP surgery (AP group), respectively. Although PAP surgery was associated with a significantly longer operation time, the total blood loss volume was significantly less in the PAP group than the AP group. Compared with the AP group, the PAP group showed significantly larger postoperative changes in radiological parameters in the sagittal and coronal planes. The overall complication rate did not differ significantly between the two groups.ConclusionTwo-stage PAP surgery provided effective correction of rigid kyphoscoliosis without increasing blood loss and postoperative complication rates.

Lumbar Lordosis Redistribution and Segmental Correction in Adult Spinal Deformity: Does it Matter?

Retrospective analysis of prospectively collected data. Evaluate the impact of correcting normative segmental lordosis values on postoperative outcomes. Restoring lumbar lordosis magnitude is crucial in adult spinal deformity surgery, but the optimal location and segmental distribution remain unclear. Patients were grouped based on offset to normative segmental lordosis values, extracted from recent publications. Matched patients were within 10% of the cohort's mean offset, less than or over 10% were undercorrected and overcorrected. Surgical technique, patient-reported outcome measures, and surgical complications were compared across groups at baseline and two years. In total, 510 patients with a mean age of 64.6, a mean Charlson comorbidity index 2.08, and a mean follow-up of 25 months. L4-5 was least likely to be matched (19.1%), while L4-S1 was the most likely (24.3%). More patients were overcorrected at proximal levels (T10-L2; undercorrected, U: 32.2% vs. matched, M: 21.7% vs. overcorrected, O: 46.1%) and undercorrected at distal levels (L4-S1: U: 39.0% vs. M: 24.3% vs. O: 36.8%). Postoperative Oswestry disability index was comparable across correction groups at all spinal levels except at L4-S1 and T10-L2/L4-S1, where overcorrected patients and matched were better than undercorrected (U: 32.1 vs. M: 25.4 vs. O: 26.5, P =0.005; U: 36.2 vs. M: 24.2 vs. O: 26.8, P =0.001; respectively). Patients overcorrected at T10-L2 experienced higher rates of proximal junctional failure (U: 16.0% vs. M: 15.6% vs. O: 32.8%, P <0.001) and had greater posterior inclination of the upper instrumented vertebrae (U: -9.2±9.4° vs. M: -9.6±9.1° vs. O: -12.2±10.0°, P <0.001), whereas undercorrection at these levels led to higher rates of revision for implant failure (U: 14.2% vs. M: 7.3% vs. O: 6.4%, P =0.025). Patients undergoing fusion for adult spinal deformity suffer higher rates of proximal junctional failure with overcorrection and increased rates of implant failure with undercorrection based on normative segmental lordosis. Level IV.

Osteoporosis is a Risk Factor for Proximal Junctional Failure Following Long Spinal Fusion for Adult Spinal Deformity

Background: Bone health has emerged as a critical modifiable risk factor for complications following adult spinal deformity correction. Among these complications, mechanical issues and proximal junctional kyphosis/failure remain particularly challenging, affecting up to 61% and 44% of patients, respectively. We hypothesized that osteoporotic patients undergoing deformity correction experience higher rates of instrumentation failure and proximal junctional kyphosis/failure. Purpose: To evaluate and compare the complication profiles of osteoporotic and non-osteoporotic patients undergoing long thoracolumbar fusion for adult spinal deformity. Study Design: Retrospective comparative study Patient Sample: adult spinal deformity patients who underwent long thoracolumbar spinal fusion (&gt;7 levels) at two large academic medical centers between 2010 and 2019. Outcome Measures: The primary outcome was all-cause revision surgery. Secondary outcomes included pseudarthrosis with or without implant failure, proximal junctional kyphosis/failure rates, infection rates, and time to complication occurrence. Methods: This retrospective, multicenter study analyzed deformity patients undergoing long-segment instrumentation (≥7 levels) with a minimum two-year follow-up. Exclusion criteria included spinal deformity secondary to tumor, infection, trauma, or neuromuscular disorders. Preoperative osteoporosis status was determined using dual-energy X-ray absorptiometry (DXA) T-scores at the hip and femoral neck. The complication profiles of osteoporotic and non-osteoporotic deformity patients were compared using Chi-squared or Fisher’s exact tests for categorical variables and two-tailed t-tests for continuous variables. Results: Among 399 adult spinal deformity patients, 131 (32.8%) were osteoporotic. Osteoporotic patients were significantly older than their non-osteoporotic counterparts [66.43 (SD: 8.9) vs. 63.51 (SD: 8.9), P = 0.0018]. The overall complication rate was significantly higher in osteoporotic patients compared to non-osteoporotic patients [40.5% (n = 53) vs. 28.0% (n = 75), P = 0.0122]. Incidences of PJK [35.1% (n = 46) vs. 21.6% (n = 58), P = 0.0040] and PJF [19.8% (n = 26) vs. 6.7% (n = 18), P = 0.0001] were also higher in the osteoporotic group, while rates of construct failure/pseudarthrosis [11.5% vs. 15.7%, P = 0.2578] and infection [4.6% vs. 3.7%, P = 0.6849] showed no significant differences. Time to pseudarthrosis (8.1 vs. 8.3 months, P = 0.4582), infection (4.7 vs. 1.5 months, P = 0.0773), PJF (9.3 vs. 10.1 months, P = 0.7300), and overall time to first complication (8.4 vs. 7.6 months, P = 0.5119) were similar between the groups. Conclusions: Osteoporotic patients have increased risk of proximal junctional kyphosis and failure compared to non-osteoporotic patients, highlighting the need for preoperative osteoporosis surveillance, optimization, and postoperative monitoring to mitigate complications.

Comparison of Same-Day versus Staged Circumferential Spinal Fusion for Adult Spinal Deformity: A Systematic Review and Meta-Analysis

Comparison of Same-Day versus Staged Circumferential Spinal Fusion for Adult Spinal Deformity: A Systematic Review and Meta-Analysis

Predicting Postoperative Complications, Intensive Care Unit Length of Stay, and Transfusion Requirements in Posterior Spinal Fusion for Adult Spinal Deformity using Artificial Intelligence

Predicting Postoperative Complications, Intensive Care Unit Length of Stay, and Transfusion Requirements in Posterior Spinal Fusion for Adult Spinal Deformity using Artificial Intelligence

Spinopelvic Parameters in the Elderly: Does Inadequate Correction Portend Worse Outcomes?

This study aimed to compare the outcomes of corrective fusion for adult spinal deformity (ASD) in older people using two different sagittal correction goals: the conventional formula of "pelvic incidence (PI)-lumbar lordosis (LL) mismatch <10°" and an undercorrection strategy based on the range of 10°≤PI-LL≤20°. A total of 102 consecutive patients (11 male and 91 female patients; mean age, 72.0 years) aged above 65 years with scoliosis >20° or LL<20° who had undergone long-segment fusion from the lower thoracic spine to the pelvis for ASD and had been followed-up for a minimum of two years at our institution since March 2013 were included in this retrospective study. After excluding patients with PI-LL≤-10° on postoperative standing radiographs, the remaining patients were divided into two groups: 31 patients with 10°≤PI-LL≤20° (U group) and 63 patients with -10°<PI-LL<10° (M group). Radiological and clinical outcomes were compared between the groups. The incidence of proximal junctional kyphosis and mechanical failure was not significantly different between the groups (p=0.659 and 1.000, respectively). After excluding patients who underwent reoperation due to mechanical failure, there were no differences in the Oswestry Disability Index (ODI) and each domain of the Visual Analog Scale score, Scoliosis Research Society-22r patient questionnaire (SRS-22r), or the short form 36 health survey questionnaire at the final observation between the U (n=27) and M (n=57) groups. In addition, the non-inferiority and equivalence of the U group to the M group were demonstrated in all domains of the SRS-22r and ODI. Furthermore, the superiority of the U group was demonstrated by the functional domain of SRS-22r. For the sagittal correction goal in corrective fusion surgery for ASD in the elderly, strict adherence to "PI-LL mismatch <10°" is not necessary and "PI-LL≤20°" may be acceptable.

The Re-Evaluation of Frailty in Predicting Complications after Long-Segment Spinal Fusion for Adult Spinal Deformity

To evaluate on a national scale how frailty status (stratified using the 5-item Modified Frailty Index (mFI-5)) affects the operative characteristics of and complications after long-segment spinal fusion (LSF) for adult spinal deformity (ASD). Adults undergoing LSF of ≥3 vertebrae in the National Surgical Quality Improvement Program database years 2015-2020 were split into 2 cohorts: nonfrail with mFI= 0 or 1; frail with mFI ≥2. Demographics, operative characteristics, and 30-day complications were contrasted between the cohorts using the Student's t-test, the Fisher's exact test, or a multivariate analysis when appropriate. In the 340 LSF cases collected, 268 fell into the nonfrail cohort and 72 into the frail cohort. The frail cohort constituted a high rate of geriatric age (65.3% vs. 38.1%; P < 0.001), higher body mass index (32.9 ± 0.86 vs. 30.2 ± 0.39; P= 0.005), and more comorbidities in 9 of 14 measures. After surgery, the frail cohort experienced more urinary tract infections (odds ratio [OR], 3.33; confidence interval [CI], 1.01-10.94; P= 0.04). However, the frail cohort shared similarities with the nonfrail cohort in terms of length of stay (5.11 ± 0.51 vs. 6.01 ± 1.62 days; P= 0.60), home discharge (OR, 0.76; CI, 0.42-1.39; P= 0.38), readmission (OR, 2.45; CI, 0.87-6.89; P= 0.09), and overall rate of complications (OR, 0.89; CI, 0.50-1.59; P= 0.70). Despite trends found in past studies of ASD, this analysis showed that the frailty status of mFI ≥2 is a poor predictor of surgical and hospitalization course and overall complications in LSF when examined up to 30 days postoperatively.

Comparison of Staged vs Same-Day Circumferential Spinal Fusions for Adult Spinal Deformity.

Patients often undergo circumferential (anterior and posterior) spinal fusions to maximize adult spinal deformity (ASD) correction and achieve adequate fusion. Currently, such procedures are performed in staged (ST) or same-day (SD) procedures with limited evidence to support either strategy. This study aims to compare perioperative outcomes and costs of ST vs SD circumferential ASD corrective surgeries. This is a retrospective review of patients undergoing circumferential ASD surgeries between 2013 and 2018 in a single institution. Patient characteristics, preoperative comorbidities, surgical details, perioperative complications, readmissions, total hospital admission costs, and 90-day postoperative care costs were identified. All variables were tested for differences between ST and SD groups unadjusted and after applying inverse probability weighting (IPW), and the results before and after IPW were compared. The entire cohort included a total of 211 (ST = 50, SD = 161) patients, 100 of whom (ST = 44, SD = 56) underwent more than 4 levels fused posteriorly and anterior lumbar interbody fusion (ALIF). Although patient characteristics and comorbidities were not dissimilar between the ST and SD groups, both the number of levels fused in ALIF and posterior spinal fusion (PSF) were significantly different. Thus, using IPW, we were able to minimize the cohort incongruities in the number of levels fused in ALIF and PSF while maintaining comparable patient characteristics. In both the whole cohort and the long segment fusions, postoperative pulmonary embolism was more common in ST procedures. After adjustment utilizing IPW, both groups were not significantly different in disposition, 30-day readmissions, and reoperations. However, within the whole cohort and the long segment fusion cohort, the ST group continued to show significantly increased rates of pulmonary embolism, longer length of stay, and higher hospital admission costs compared with the SD group. Adjusted comparisons between ST and SD groups showed staging associated with significantly increased length of stay, risk of pulmonary embolism, and admission costs.

Minimal Clinically Important Differences in Gait and Balance Ability in Patients Who Underwent Corrective Long Spinal Fusion for Adult Spinal Deformity.

Retrospective observational study. The risk of a femoral neck fracture due to a fall after adult spinal deformity surgery has been reported. One of the most significant factors among walking and balance tests in post-operative ASD patients was the timed up-and-go test (TUG). This study aims to calculate the minimal clinically important difference (MCID) in balance tests after ASD surgery. Forty-eight patients, 4 males and 44 females, were included by exclusion criteria in 66 consecutive patients who underwent corrective surgery as a treatment for ASD at our institution from June 2017 to February 2022. The inclusion criteria for this study were age ≥50 years; and no history of high-energy trauma. The exclusion criteria were dementia, severe deformity of the lower extremities, severe knee or hip osteoarthritis, history of central nervous system disorders, cancer, and motor severe paralysis leading to gait disorders. The surgeries were performed in two stages, first, the oblique lumber interbody fusion (OLIF) L1 to L5 (or S1), and second, the posterior corrective fusion basically from T10 to pelvis. For outcome assessment, 10 m walk velocity, TUG, ODI, and spinopelvic parameters were used. Ten meter walk velocity of pre-operation and post-operation were 1.0 ± 0.3 m/s and 1.2 ± 0.2 m/s, respectively (p < 0.01). The TUG of pre-operation and post-operation were 12.1 ± 3.7 s and 9.7 ± 2.2 s, respectively (p < 0.01). The ODI improved from 38.6 ± 12.8% to 24.2 ± 15.9% after surgery (p < 0.01). All post-operative parameters except PI obtained statistically significant improvement after surgery. This is the first report of MCID of the 10 m walk velocity and TUG after ASD surgery. Ten meter walk velocity and the TUG improved after surgery; their improvement values were correlated with the ODI. MCID using the anchor-based approach for 10 m walk velocity and the TUG were 0.10 m/s and 2.0 s, respectively. These MCID values may be useful for rehabilitation after ASD surgery.

Polymethyl methacrylate augmentation and proximal junctional kyphosis in adult spinal deformity patients.

Proximal junctional kyphosis (PJK) is a complication following surgery for adult spinal deformity (ASD) possibly ameliorated by polymethyl methacrylate (PMMA) vertebroplasty of the upper instrumented vertebrae (UIV). This study quantifies PJK following surgical correction bridging the thoracolumbar junction ± PMMA vertebroplasty. ASD patients from 2013 to 2020 were retrospectively reviewed and included with immediate postoperative radiographs and at least one follow-up radiograph. PMMA vertebroplasty at the UIV and UIV + 1 was performed at the surgeons' discretion. Of 102 patients, 56% received PMMA. PMMA patients were older (70 ± 8 vs. 66 ± 10, p = 0.021), more often female (89.3% vs. 68.2%, p = 0.005), and had more osteoporosis (26.8% vs. 9.1%, p = 0.013). 55.4% of PMMA patients developed PJK compared to 38.6% of controls (p = 0.097), and the rate of PJK development was not different between groups in univariate survival models. There was no difference in PJF (p > 0.084). Reoperation rates were 7.1% in PMMA versus 11.4% in controls (p = 0.501). In multivariable models, PJK development was not associated with the use of PMMA vertebroplasty (HR 0.77, 95% CI 0.38-1.60, p = 0.470), either when considered overall in the cohort or specifically in those with poor bone quality. PJK was significantly predicted by poor bone quality irrespective of PMMA use (HR 3.81, p < 0.001). In thoracolumbar fusions for adult spinal deformity, PMMA vertebroplasty was not associated with reduced PJK development, which was most highly associated with poor bone quality. Preoperative screening and management for osteoporosis is critical in achieving an optimal outcome for these complex operations. 4, retrospective non-randomized case review.