Coronal Imbalance Research Articles

The Variability of Pelvic Obliquity Measurements in Patients with Neuromuscular Scoliosis.

Background:Pelvic obliquity (PO), or pelvic alignment in the coronal plane, is an important radiographic parameter to indicate fusion levels and judge success of scoliosis correction in patients with neuromuscular scoliosis. There are multiple commonly used techniques to measure PO that have good to excellent interrater and intrarater reliability, but these different methods yield inconsistent values when used on the same radiograph. This study evaluates the inconsistency in the magnitude of PO measurements for patients with neuromuscular scoliosis among 5 common measurement techniques.Methods:Radiographs of 63 patients with neuromuscular scoliosis were evaluated by 5 raters. Each rater measured PO on each radiograph using the Osebold, O’Brien, Allen and Ferguson, Lindseth, and Maloney techniques. Patients were divided into 2 cohorts based on coronal balance or imbalance. Interrater and intrarater analyses were performed using a 2-way random effects model to calculate absolute agreement. The mean difference in PO between all possible pairs of the techniques was compared using a 2-tailed t test.Results:The Maloney and Osebold techniques demonstrated excellent interrater reliability, and the Maloney, Osebold, and O’Brien techniques demonstrated excellent intrarater reliability. Significant differences in PO measurement were found in 6 of the 10 comparisons for the balanced spines and 8 of the 10 comparisons for the unbalanced spines. Variability in measurement was captured by best-fit lines, which demonstrated greater dispersion between the means for the Osebold and Maloney techniques in the unbalanced spines than in the balanced spines.Conclusions:To our knowledge, this study is the first to evaluate mean differences in magnitude of PO among common measurement techniques while accounting for coronal imbalance. Although there is no gold standard for measuring PO, the Maloney and Osebold techniques are the most consistent. This study suggests that those 2 techniques can be used interchangeably when the spine is coronally balanced, but the Osebold technique becomes more inconsistent than the Maloney technique when coronal imbalance exceeds 2 cm.Clinical Relevance:This information is relevant to surgeons using PO to plan fusion levels and striving for objective ways to judge correction intraoperatively as well as for researchers compiling PO data from multiple centers or studies.

Investigation of sitting position of paralympic wheelchair basketball players

Purpose: The aim of this study was to examine the sitting position (posture) of wheelchair basketball (WB) players who cannot walk and can walk in daily life and to compare them with the able-bodied sedentary individuals. Methods: A total of 22 male individuals, including six WB players who could not walk in daily life, eight WB players who walked in daily life, and eight able-bodied sedentary individuals (control group) were included in the study. Posture analysis of individuals was evaluated using rastersterographic system DIERS formetric 4D device. Kruskal–Wallis test was used to compare the data obtained during posture analysis. The Mann–Whitney U-test was used to determine which group caused the difference in the data determined to be different. Statistical significance level was taken as P < 0.05. Results: Trunk-length, sacrum-width, sagittal and coronal imbalance, trunk-torsion, pelvic-obliqueness, pelvic-torsion, pelvic-inclination and fleche-cervicale were found to be values similar in the three groups (P > 0.05). It was determined that the lumbar lordosis and thoracic kyphosis angles were different between the groups, and the lumbar lordosis and thoracic kyphosis angles of the WB players who could not walk in daily life were higher than those of the WB players who walked in daily life and the control group (P < 0.05). Conclusions: Based on the results of our study, we suggest evaluating the sitting postures of WB players and rehabilitating WB players, especially those who cannot walk in daily life, with posture corrective exercises aimed at reducing and normalizing thoracic kyphosis.

Improving effects of vertebral column manipulator on lower instrumented vertebrate tilt and lumbar mobility of lenke 5C patients for follow-up of minimum 2 years

ObjectiveTo compare the lower instrumented vertebra (LIV) related parameters and lumbar function in the long-term follow-up of Lenke 5C adolescent idiopathic scoliosis patients treated with vertebrate column manipulator (VCM) or simple rod derotation (SRD) maneuver. Methods43 Lenke 5C patients treated with VCM or SRD maneuver were retrospectively enrolled without randomization. The clinical and radiographic data were completely documented. Thorough comparisons of relevant variables were performed at three different time points (preoperative, immediately postoperative, 2-year follow-up) between the two groups. ResultsThe curvatures of all patients were satisfactorily corrected with good sagittal achieved. No severe postoperative complications occurred. The postoperative LIV rotation of VCM group was significantly smaller than SRD group (7.12° ± 4.16° vs 11.64° ± 5.40°, P < 0.01). The LIV-tilt of VCM group were significantly better improved immediately after surgery (5.58° ± 3.60° vs 7.96° ± 5.89°, P = 0.021) and at 2-year follow-up (4.78° ± 3.11° vs 8.59° ± 5.51°, P < 0.01). Meanwhile, there was a spontaneous improvement of postoperative LIV-tilt in VCM group but an aggravation in SRD group. The relevant parameters that correlated with LIV-tilt were postoperative LIV rotation (r2 = 0.336, P < 0.001), 2-year LIV rotation (r2 = 0.410, P < 0.001) and 2-year coronal imbalance (r2 = 0.282, P < 0.001). In addition, VCM group conserved more lumbar mobility (46.90° ± 17.34° vs 30.91° ± 14.27°, P < 0.01). ConclusionsVCM system on Lenke 5C patients could improve the LIV rotation, LIV-tilt and the risk of trunk decompensation and distal adding-on more efficaciously than SRD maneuver in follow-up, as well as conserving more lumbar mobility.

Sacral Agenesis: A Neglected Deformity That Increases the Incidence of Postoperative Coronal Imbalance in Congenital Lumbosacral Deformities.

Study Design:A retrospective study.Objectives:To identify if there is a link between sacral agenesis (SA) and post-operative coronal imbalance in patients with congenital lumbosacral deformities.Methods:This study reviewed a consecutive series of patients with congenital lumbosacral deformities. They had a minimum follow-up of 2 years. According to different diagnosis, they were divided into SA and non-SA group. Comparison analysis was performed between patients with and without post-operative coronal imbalance and risk factors were identified.Results:A total of 45 patients (18 in SA group and 27 in non-SA group) were recruited into this study, among whom 33 patients maintained coronal balance while 12 demonstrated postoperative coronal imbalance at last follow-up (14.32 ± 7.67 mm vs 35.53 ± 3.91 mm, P < 0.001). Univariate analysis showed that preoperative lumbar Cobb angle, immediate postoperative coronal balance distance and diagnosis of SA were significantly different between patients with and without post-operative coronal imbalance (P < 0.05). Binary logistic regression analysis showed that SA was an independent risk factor for postoperative coronal imbalance.Conclusions:As an independent risk factor for postoperative coronal imbalance, high level of suspicion of SA should be aware in children with congenital lumbosacral deformities. Sufficient bone grafts at sacroiliac joint are recommended for SA patients to prevent postoperative coronal imbalance.

Directionality of Lumbosacral Fractional Curve Relative to C7 Plumb Line, A Novel Index Associated with Postoperative Coronal Imbalance in Patients with Degenerative Lumbar Scoliosis.

Retrospective case-control radiographic study. The aim of this study was to explore whether directionality of lumbosacral fractional curve relative to C7 plumb line (PL) affected postoperative coronal imbalance in patients with degenerative lumbar scoliosis (DLS). The spatial relationship between lumbar main curve and C7 PL was reported to have impact on postoperative coronal imbalance in DLS. Although fractional curve played more important role than lumbar main curve in DLS, the spatial relationship between fractional curve and C7 PL and their impact on the postoperative coronal balance are still unknown. One hundred one DLS patients treated with posterior instrumented fusion were reviewed. Coronal measurements included C7 migration, fractional curve, L4/L5 coronal tilt, major Cobb angle. Based on directionality of fractional curve (orientation of L4 coronal tilt was used to represent it) relative to C7 PL preoperatively, coronal patterns was separated into: consistency pattern, L4 coronally tilts toward C7 PL; opposition pattern, L4 coronally tilts opposite C7 PL; the distributions of these two patterns and Type A, B,C were analyzed. According to postoperative C7 migration, patients were divided into imbalanced group and balanced group. Compared to balanced group, the imbalanced group had higher percentage of preoperative consistency pattern (80.6% vs. 33.8%, P < 0.001) and Type C (36.1% vs. 7.7%, P < 0.001); larger fractional curve or L4 coronal tilt pre- and postoperatively, larger L5 coronal tilt postoperatively. Logistic regression analysis showed predictors for postoperative coronal imbalance were consistency pattern (odds ratio [OR] 5.103, 95% confidence interval [CI]: 1.660-15.687, P = 0.004) and type C (OR 4.061; 95% CI: 1.056-15.618; P = 0.041). Directionality of fractional curve relative to C7 PL was associated with postoperative coronal imbalance in DLS patients. In addition to type C, consistency pattern might be an independent risk factor for postoperative coronal imbalance.Level of Evidence: 3.

Spinal balance and lumbar curve stability after selective thoracic fusion in idiopathic scoliosis.

Selective thoracic fusion (STF) for double curve patterns in idiopathic scoliosis is an attractive treatment option. However, short-term coronal decompensation and truncal imbalance are known findings. Previous studies with hook constructs showed that eventually balance is achieved via an increase in lumbar curve magnitude, as the lumbosacral obliquity did not change following surgery. Our aim is to investigate patients with idiopathic curves who underwent STF using all-pedicle screw constructs to determine if the uninstrumented lumbar curve and lumbosacral obliquity responded in the same manner as was previously reported with all-hook constructs. 102 consecutive patients with Lenke 1B, 1C or 3C curves who underwent STF using all-screw constructs at a single institution were included in this study. Radiographic assessment was performed, and patient reported outcomes were obtained. Subgroup analyses were performed based on preoperative thoracic: lumbar curve ratio as well as lumbar curve magnitude. Overall, the patients showed statistically significant improvement in both trunk shift and L4-pelvis obliquity at final follow-up. The uninstrumented lumbar curves trended toward improvement over time, but did not reach statistical significance (p = 0.107). SRS-30 scores were statistically significantly improved in multiple domains. Selective thoracic fusion is an excellent treatment option in most double curve patterns. Balance in the coronal plane is predictably achieved at 2-year follow-up. The lumbosacral obliquity improves more with screw technology than was previously found with hook constructs; therefore, the improvement in balance over time does not depend upon an increase in the uninstrumented lumbar curve. IV.

Risk factors for postoperative coronal decompensation in adult lumbar scoliosis after posterior correction with osteotomy.

To determine potential risk factors for postoperative coronal imbalance following posterior osteotomy for adult scoliosis. A total of 74 patients underwent osteotomy for rigid adult lumbar scoliosis. A group of 20 patients with postoperative coronal imbalance was identified. Clinical data and surgical strategies were compared to determine the risk factors, including age, gender, etiology, Cobb angle, preoperative coronal balance distance, direction of preoperative imbalance, T1 tilt, tilt of upper instrumented vertebra (UIV), UIV translation, location of UIV (T6 above or below), fusion to L5 or S1, lower instrumented vertebra (LIV) tilt, LIV rotation, screw density, osteotomy procedure (PSO or SPOs) and use of iliac screws. Comparison between patients with and without postoperative coronal imbalance showed that postoperative coronal imbalance occurred in older patients and those with degenerative scoliosis as the etiology, UIV above T6, preoperative LIV rotation, preoperative LIV tilt and preoperative coronal imbalance towards the convex side and who underwent Smith-Petersen osteotomy. All seven parameters were included in the logistic regression analysis. UIV above T6 (P = 0.010), LIV rotation (P = 0.012) and preoperative coronal imbalance towards the convex side (P = 0.005) were identified as risk factors for postoperative coronal imbalance after osteotomy. Patients with preoperative coronal imbalance towards the convex side (UIV above T6) and LIV rotation were more likely to develop coronal imbalance than those without risk factors. Older patients and those with degenerative scoliosis were also at a relatively higher risk of postoperative coronal imbalance.

Risk Factors Associated With Failure to Reach Minimal Clinically Important Difference After Correction Surgery in Patients With Degenerative Lumbar Scoliosis.

A retrospective study. The aim of this study was to evaluate the factors affecting health-related quality of life (HRQOL) after surgery in patients with degenerative lumbar scoliosis (DLS) by minimum clinically important difference (MCID). MCID has been introduced in the adult spinal deformity to quantify the absolute minimum change that can be considered a success. There are limited data available to identify factors affecting reaching MCID after DLS surgery. This study reviewed a cohort of 123 DLS patients after correction surgery and with a minimum 2-year follow-up (FU). Inclusion criteria included age ≥40 and minimum five vertebrae fused and the availability of Scoliosis Research Society (SRS)-22 scores and radiographic data at baseline (BL) and FU. Using a multivariate analysis, two groups were compared to identify possible risk factors: those who reached MCID in the all four SRS domains (N = 65) at the last FU and those who missed MCID (N = 58). At baseline, patients differed significantly from matched normative data in all SRS-22 domains. The baseline HRQOL was comparable in reached MCID and missed MCID group patients (P > 0.05). The HRQOL scores at FU were significantly higher than those at baseline. Of 123 included patients, 77.2% (N = 95), 72.4% (N = 89), 76.4% (N = 94), and 89.4% (N = 110) reached MCID in SRS pain, activity, appearance, and mental domain, respectively. Pelvic incidence (PI) >55°, lumbar lordosis (LL) loss >4.65°, coronal imbalance at FU, sagittal vertical axis (SVA) at FU >80 mm, and presence of proximal junctional kyphosis (PJK) and distal junctional problem (DJP) had negative effects on the recovery process. Factors affecting reaching MCID after surgery for DLS were higher PI, LL loss, coronal imbalance, severe sagittal imbalance, and the occurrence of PJK and DJP. 4.

Orientation of L4 coronal tilt relative to C7 plumb line as a predictor for postoperative coronal imbalance in patients with degenerative lumbar scoliosis

The study design is case–control. To evaluate the impact of preoperative coronal patterns based on the relationship between orientation of L4 coronal tilt and C7 plumb line on immediate postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients. Although lumbosacral fractional curve has been long stressed in correction surgery of DLS, there is paucity of literature focusing on preoperative coronal pattern based on the relationship between orientation of L4 coronal tilt and C7 plumb line and its impact on immediate postoperative coronal imbalance in DLS patients. A consecutive series of DLS patients who underwent deformity correction surgery via posterior-only approach were reviewed. According to the relationship between orientation of L4 coronal tilt and C7 plumb line preoperatively, a total of 77 DLS patients who underwent posterior spinal corrective surgery were classified into: 1. Coronal consistency pattern, L4 coronally tilts toward C7 plumb line; 2. Coronal opposition pattern, L4 coronally tilts opposite C7 plumb line. Coronal imbalance was defined as global coronal malalignment (GCM) on either side more than or equal to 20 mm. Whole-spine standing radiographs of both pattern groups were assessed preoperatively and postoperatively. There were 37 patients with coronal consistency pattern and 40 patients with coronal opposition pattern. Compared to patients with coronal opposition pattern, patients with coronal consistency pattern had significantly higher postoperative GCM (P = 0.028), lower amount of GCM correction (P = 0.013) and higher incidence of postoperative coronal imbalance (P = 0.001); further logistic regression analysis revealed coronal consistency pattern was associated with increased odds of postoperative coronal imbalance (odds ratio: 5.981; 95% confidence interval 2.029–17.633; P = 0.001). DLS patients with preoperative coronal consistency pattern carried greater risk for immediate postoperative coronal imbalance following posterior long correction surgery.Level of evidence 3

Factors related to postoperative coronal imbalance in adult lumbar scoliosis.

The object of this study was to analyze the prevalence of postoperative coronal imbalance (CIB) and related factors in patients with adult lumbar scoliosis. This was a retrospective single-center study of data from patients with adult spinal deformity (ASD) who had undergone corrective surgery performed by a single surgeon between 2009 and 2017. The inclusion criteria were as follows: 1) age at surgery > 40 years, 2) Cobb angles of the thoracolumbar/lumbar (TL/L) curve > 40°, 3) upper instrumented vertebra of T9 or T10, 4) lowest instrumented vertebra of L5 or the pelvis, and 5) minimum 2-year follow-up period. Radiographic parameters were measured before surgery, 2 weeks after surgery, and at the latest follow-up. Curve flexibility was also assessed using side bending radiographs. Clinical outcomes were evaluated using the 22-Item Scoliosis Research Society Outcomes Questionnaire (SRS-22) and the SF-36. CIB was considered to have occurred if the C7 plumbline was more than 2.5 cm lateral to the central sacral vertical line (i.e., coronal vertical axis [CVA] > 2.5 cm) at the final follow-up. Parameters between the patients with (CIB group) and without (coronal balance [CB] group) CIB were compared, and factors related to CIB were evaluated. From among 66 consecutively treated ASD patients, a total of 37 patients (mean age at surgery 66.3 years, average follow-up 63 months) met the study inclusion criteria. CIB was found in 6 patients at the final follow-up (16.2%), and the CVA of all patients in the CIB group shifted to the convex side of the TL/L curve. A comparative analysis between the CB and CIB groups, respectively, at the final follow-up indicated the following factors were related to CIB: lumbosacral (LS) curve, 11.0°/16.5° (p = 0.02); LS correction rate (CR), 61%/47% (p = 0.02); and CR ratio (LS vs TL/L), 0.93/0.67 (p = 0.0002). Regarding clinical outcomes, the satisfaction domain of the SRS-22 (CB 4.4 vs CIB 3.5) showed a significant difference between the CIB and CB groups (p = 0.02), and patients in the CB group tended to score better on the pain domain (CB 4.3 vs CIB 3.7), but the difference was not significant (p = 0.06). Postoperative CIB negatively impacted patients' HRQOL. An imbalanced correction ratio between the TL/L and LS curves may cause postoperative CIB. Therefore, adequate correction of the LS curve may prevent postoperative CIB.

A case report of severe degenerative lumbar scoliosis associated with windswept lower limb deformity

BackgroundThe windswept lower limb deformity describes valgus deformity in one leg with varus deformity in the other. It is mostly seen in young children with metabolic bone diseases (such as rickets) and may lead to leg length discrepancy (LLD) and Degenerative scoliosis (DS) in older age. To the best of our knowledge, there was no report of the spinal surgery in patient with severe DS associated with windswept deformity. The objective of this study is to report the unique case of a 60-year-old woman with severe degenerative scoliosis (DS) associated with windswept deformity caused by rickets who underwent a posterior correction and fusion surgery in spine.Case presentationThe patient was diagnosed as rickets windswept lower limb deformity for 50 years but never went through routine treatment. Then, she performed lumbar scoliosis for more than 20 years and suffered from severe back pain for 4 years. After overall clinical evaluation and radiographic measures, we performed a posterior surgical correction and fusion from T9-L5. With this surgery, the main thoracolumbar curve Cobb angle corrected from 72.5° to 21.0°, the coronal balance from 0 cm to 2.0 cm while the sagittal vertical axis (SVA) from 1.5 cm to − 1.0 cm. At 2 years postoperative follow-up, her back pain has almost completely relieved with a satisfied fixation and bone fusion showed on CT scans. However, a coronal imbalance was found with C7-CSVLdistance equal to 4.0 cm. This coronal imbalance was highly correlated to the untreated LLD and pelvic obliquity, and should be improved by standing posture or shoe lifts.ConclusionsFor such patient, the pure spinal correction and fusion surgery, in spite of lower limbs deformity, can achieve good relieve of back pain symptom, however may accompany by the complication of coronal imbalance due to the unimproved pelvic obliquity and LLD. However, longer follow-up is necessary to observe the long-term outcome of this patient’s postoperative coronal imbalance.

Surgical challenges with spinal balance in adult spinal deformities-the forgotten coronal plane

This article gives abrief overview of the importance, planning and correction of coronal spinal imbalance in patients with adult and pediatric spinal deformity.

136. Can supine radiographs help in saving fusion levels in adolescent idiopathic scoliosis?

BACKGROUND CONTEXT Supine radiographs have previously been used to indicate flexibility in patients with adolescent idiopathic scoliosis (AIS). However, their utility for selecting LIV has not been previously demonstrated. PURPOSE To demonstrate whether supine radiographs may be used to determine lowest instrumented vertebral (LIV) level. STUDY DESIGN/SETTING Retrospective cohort study. PATIENT SAMPLE This study included 22 patients with Lenke 1 or 2 AIS treated with posterior fusion. OUTCOME MEASURES Coronal imbalance (CSVL) on immediate postoperative films and final follow-up. METHODS Preoperative standing and supine radiographs were taken and changes in stable vertebra (SV), last touched vertebra (LTV), neutral vertebra (NV), and end vertebra (EV) from preoperative standing and supine films were determined. This was used to define supine flexibility as any change in SV or LTV between standing and supine radiographs. Multivariate analysis, controlling for preoperative coronal imbalance (CSVL) and lumbar apical translation, was used to determine the relative change in postoperative CSVL based on LIV to the standing SV, standing LTV, or supine LTV. RESULTS There was a significant decrease in main thoracic (MT) (-15.1°), thoracolumbar (TL) (-11.0°) Cobb angle, and in thoracic kyphosis (TK) (-9.2°) between standing and supine radiographs (p 0.05). In total, 15 patients (68.2%) demonstrated supine flexibility, or a change in SV or LTV between standing and supine radiographs. Postoperatively, there was a significant decrease in MT (59.2°to 18.3°) and TL Cobb angle (32.8° to 10.6°) and an increase in TK (26.6° to 31.4°; p CONCLUSIONS In patients who demonstrate supine flexibility (change in stable or last touched vertebra on from standing to supine radiographs), fusion to the supine last touched vertebra may be appropriate. This may save as many as 2.1 levels in 68.2% percent of patients compared to fusion to the standing stable vertebra. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

P118. Pelvic fixation improves coronal balance, decreases pelvic obliquity, but is not essential in neuromuscular scoliosis (NMS)

BACKGROUND CONTEXT Non-ambulatory NMS patients are typically fused to the pelvis to augment fixation, prevent loss of correction and improve seating balance. However, pelvic fixation extends the length of surgery, increases EBL and may increase pain. PURPOSE This study aims to evaluate the radiographic outcomes after PSF with all pedicle screws in NMS fixated (FP) and not fixated at the pelvis (NFP). STUDY DESIGN/SETTING Retrospective and Prospective Review. PATIENT SAMPLE Ambulatory and non-ambulatory neuromuscular patients undergoing spinal deformity correction at one institution. OUTCOME MEASURES Preoperative and postoperative radiographic parameters and intraoperative clinical measures (estimated blood loss, operative time). METHODS Radiographic measurements, OR parameters and demographics were recorded for neuromuscular surgeries between 2006-2016. Patients were divided into NFP and FP. Median values and Wilcoxon rank sum tests were used. Subanalysis was performed for patients with preoperative PO 20°. RESULTS There were 91 patients; 63 were non-ambulatory. Between NFP (n=54) and FP (n=37), preop Cobb (p=0.215), PO (p=0.158), and decompensation (p=0.247) were similar. Both had similar final Cobb (p=0.146) and PO (p=0.162), but NFP had significant coronal imbalance (35.8 vs 14.6, p 20, patients had similar preop PO (p=0.545) and decompensation (p=0.075). NFP had higher final PO (p=0.123) and significantly higher decompensation (135.4 vs 25.2, p=0.008). The change in PO (p=0.298) and decompensation (p=0.616) from postop to final was similar. CONCLUSIONS NFP with preop PO>20 had significant coronal imbalance and PO at final follow-up. Change in PO and coronal balance over time was similar between the two groups in less severe PO. PF achieves better coronal and PO correction. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

How to select the lowest instrumented vertebra in Lenke type 5 adolescent idiopathic scoliosis patients?

BACKGROUND CONTEXTThe lowest instrumented vertebra (LIV) determination in Lenke type 5 Adolescent Idiopathic Scoliosis (AIS) requires a thorough understanding and prediction of the correction force on the LIV from coronal, sagittal, and axial plane. Although many LIV selection criteria have been reported, none of them comprehensively evaluated the multidimensional characteristics of the LIV till now. PURPOSETo develop and evaluate our LIV selection criteria in Lenke type 5 AIS patients using pedicle screw system via posterior approach. STUDY DESIGNA retrospective study. PATIENT SAMPLEAll consecutive patients with Lenke 5 curves who were treated with one-stage selective lumbar fusion using complete pedicle screw system in our center from January 2006 to December 2017, with minimum 2-year follow-up. OUTCOME MEASURESAge, gender and Risser grade, fused levels, operating time, intraoperative blood loss, complications, and Scoliosis Research Society (SRS)-22 questionnaires outcome were recorded. Coronal, sagittal, and axial parameters were measured from plain radiographs. METHODSA total of 138 consecutive patients with Lenke 5 curves treated with selective lumbar fusion were retrospectively analyzed, with minimum 2-year follow-up. Our LIV selection criteria include: (1) the most cephalad vertebrae touched by central sacrum vertical line (CSVL); (2) Nash-Moe rotation being equal or less than grade I on the standing AP radiograph; (3) CSVL cross between the two pedicles of LIV on concave bending film; (4) not at the apex of kyphosis. Radiographic data, operative data, perioperative complications and SRS-22 outcomes were collected and analyzed. RESULTSThe mean follow-up period was 50.9±24.7 months. The thoracolumbar/lumbar curve was corrected from 46.9°±8.9° before surgery to 5.5°±2.6° at the final follow-up. The C7-CSVL was 19.7±6.2 mm before surgery and 5.2±3.4 mm at the final follow-up. The LIV translation was corrected from 22.3 ±5.4 mm before surgery to 4.8 ± 2.6 mm at the final follow-up, with the correction rate of 78.4%. The LIV tilt was corrected from 21.6 ± 4.4° before surgery to 2.6 ± 2.3° at the final follow up, with the correction rate of 87.9%. Our LIV saved 0.3 level than SRS-last barely touching vertebra, 0.6 level than SRS-last substantially touching vertebra, 0.9 level than neutral vertebra, and 1.4 level than stable vertebra. CONCLUSIONThe present study indicates using our LIV criteria, our study achieved the correction rate of thoracolumbar/lumbar curve as 88.9%, with the rate of adding on or coronal imbalance as 8.7% (12/138). The criteria may provide important guidance for preoperative decision-making in Lenke 5 AIS patients, and more multicenter prospective studies with larger samples are needed to further validate the findings of this study.

Asymmetrical pedicle subtraction osteotomy for correction of concurrent sagittal-coronal imbalance in adult spinal deformity: a comparative analysis.

Rigid multiplanar thoracolumbar adult spinal deformity (ASD) cases are challenging and many require a 3-column osteotomy (3CO), specifically asymmetrical pedicle subtraction osteotomy (APSO). The outcomes and additional risks of performing APSO for the correction of concurrent sagittal-coronal deformity have yet to be adequately studied. The authors performed a retrospective review of all ASD patients who underwent 3CO during the period from 2006 to 2019. All cases involved either isolated sagittal deformity (patients underwent standard PSO) or concurrent sagittal-coronal deformity (coronal vertical axis [CVA] ≥ 4.0 cm; patients underwent APSO). Perioperative and 2-year follow-up outcomes were compared between patients with isolated sagittal imbalance who underwent PSO and those with concurrent sagittal-coronal imbalance who underwent APSO. A total of 390 patients were included: 338 who underwent PSO and 52 who underwent APSO. The mean patient age was 64.6 years, and 65.1% of patients were female. APSO patients required significantly more fusions with upper instrumented vertebrae (UIV) in the upper thoracic spine (63.5% vs 43.3%, p = 0.007). Radiographically, APSO patients had greater deformity with more severe preoperative sagittal and coronal imbalance: sagittal vertical axis (SVA) 13.0 versus 10.7 cm (p = 0.042) and CVA 6.1 versus 1.2 cm (p < 0.001). In APSO cases, significant correction and normalization were achieved (SVA 13.0-3.1 cm, CVA 6.1-2.0 cm, lumbar lordosis [LL] 26.3°-49.4°, pelvic tilt [PT] 38.0°-20.4°, and scoliosis 25.0°-10.4°, p < 0.001). The overall perioperative complication rate was 34.9%. There were no significant differences between PSO and APSO patients in rates of complications (overall 33.7% vs 42.3%, p = 0.227; neurological 5.9% vs 3.9%, p = 0.547; medical 20.7% vs 25.0%, p = 0.482; and surgical 6.5% vs 11.5%, p = 0.191, respectively). However, the APSO group required significantly longer stays in the ICU (3.1 vs 2.3 days, p = 0.047) and hospital (10.8 vs 8.3 days, p = 0.002). At the 2-year follow-up, there were no significant differences in mechanical complications, including proximal junctional kyphosis (p = 0.352), pseudarthrosis (p = 0.980), rod fracture (p = 0.852), and reoperation (p = 0.600). ASD patients with significant coronal imbalance often have severe concurrent sagittal deformity. APSO is a powerful and effective technique to achieve multiplanar correction without higher risk of morbidity and complications compared with PSO for sagittal imbalance. However, APSO is associated with slightly longer ICU and hospital stays.

Kickstand Rod Technique for Correcting Coronal Imbalance in Adult Scoliosis: 2-Dimensional Operative Video.

Restoration of spinal alignment and balance is a major goal of adult scoliosis surgery. In the past, sagittal alignment has been emphasized and was shown to have the greatest impact on functional outcomes. However, recent evidence suggests the impact of coronal imbalance on pain and functional outcomes has likely been underestimated.1,2 In addition, iatrogenic coronal imbalance may be common and frequently results from inadequate correction of the lumbosacral fractional curve.2,3 The "kickstand rod" is a recently described technique to achieve and maintain significant coronal-plane correction.4 Also, of secondary benefit, the kickstand rod may function as an accessory supplemental rod to offload stress and bolster primary instrumentation. This may reduce occurrence of rod fracture (RF) or pseudarthrosis (PA).5 Briefly, this technique involves positioning the kickstand rod on the side of coronal imbalance (along the major curve concavity or fractional curve convexity in our video demonstration). The kickstand rod spans the thoracolumbar junction proximally to the pelvis distally and is secured with an additional iliac screw placed just superior to the primary iliac screw. By using the iliac wing as a base, powerful distraction forces can reduce the major curve to achieve more normal coronal balance. This operative video illustrates the technical nuances of utilizing the kickstand rod technique for correction of severe lumbar scoliosis and coronal malalignment in a 60-yr-old male patient. Alignment correction was achieved and maintained without evidence of RF/PA after nearly 6 mo postoperatively. The patient gave informed consent for surgery and to use imaging for medical publication.

Severe persistent coronal imbalance following instrumented posterior spinal fusion for adolescent idiopathic scoliosis.

Retrospective case-control study. The aim of this study was to identify the risk factors and health-related quality of life (HRQoL) impact of severe (> 4cm) post-operative coronal imbalance at 2years following posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). Coronal imbalance is an unfavorable outcome following PSF for AIS, though the degree of imbalance in such patients is typically mild. We hypothesize that a small number of patients become and remain severely imbalanced post-operatively, though this phenomenon has not been well studied. Prospectively collected data from a large multicenter registry were reviewed. Patients with severe coronal imbalance (SCIB; > 4cm) 2years after PSF were included. Matched controls without SCIB at 2years were included at a 3:1 ratio. Comparisons were made between demographics, pre-operative radiographic measures, surgical factors, residual post-operative radiographic measures, and 2-year SRS-22 scores. Nine of 954 (0.9%) patients (88.9% females; mean age 14.8 ± 2.3years) were found to be severely imbalanced at 2years. These patients had significantly greater pre-operative bending thoracic curve magnitude (45° vs. 33°; p = 0.013), curve flexibility (22.9% vs. 63.3%; p = 0.004), and kyphosis (41° vs. 26.5°; p = 0.034) compared to matched controls. Pre-operative curve flexibility of < 20% was associated with a 23.8 times greater odds of SCIB (95% CI 2.1-250; p = 0.008). With respect to HRQoL, median SRS-22 pain (4.1 vs. 4.8; p = 0.041), self-image (3.9 vs. 4.6; p = 0.013), general function (4.5 vs. 5; p = 0.022), and total (4.1 vs. 4.7; p = 0.012) scores at 2years were significantly lower in cases compared to controls. In the present study, thoracic curve stiffness was a strong risk factor for severe post-operative coronal imbalance, which was associated with poor HRQoL measures. Increased pre-operative thoracic curve stiffness (< 20% flexibility) should raise surgeon awareness for altering surgical approach to minimize the risk of severe post-operative coronal imbalance. Level III.

Radiographic findings for surgery-related complications after pedicle subtraction osteotomy for thoracolumbar kyphosis in 230 patients with ankylosing spondylitis.

The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure. The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007). PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.

Hyper-Selective Posterior Fusion in Lenke 5C Adolescent Idiopathic Scoliosis: When Can We Stop Below the Upper End Vertebra?

A prospective analysis. To investigate whether the hyper-selective posterior fusion (upper instrumented vertebra [UIV] as the vertebra one level below the upper end vertebra [UEV], lower instrumented vertebra [LIV] as the lower end vertebra [LEV]) was applicable in posterior fusion of Lenke 5C adolescent idiopathic scoliosis (AIS) patients and what could be the indication of hyper-selective fusion. The improper UIV selection in selective fusion could lead to progressive thoracic compensatory curve, shoulder imbalance, and even coronal imbalance. However, few studies analyzed the clinical outcome of hyper-selective fusion. A prospective analysis of 80 patients with Lenke 5C AIS who underwent selective fusion was performed. According to the relationship between UEV and UIV, the patients were divided into UEV group (UIV = UEV) and UEV-1 group (UIV = UEV-1). Radiographic parameters and the incidence of postoperative proximal decompensation were compared. The Scoliosis Research Society (SRS)-22 scores were used to evaluate clinical outcomes between two groups. Thirteen patients (27%) in UEV group and six (18.75%) in UEV-1 group showed proximal decompensation during follow-up, and the incidence was equivalent (P = 0.280). Within the UEV-1 group, the patients with proximal decompensation showed similar Risser grade, baseline thoracic Cobb angle, and main Cobb angle (P = 0.611, 0.435, 0.708, respectively). However, the baseline L-T apical vertebral translation (AVT) ratio was significantly larger in patients with proximal decompensation (P = 0.028). Meanwhile, patients with proximal decompensation in UEV group showed significantly smaller preoperative UIV translation and lumbar AVT but similar postoperative UIV tilt. Hyper-selective posterior fusion strategy could be performed in Lenke 5C patients with Risser more than grade 2 and with thoracic compensatory curve over 15°. The UIV in patients with small baseline thoracic curve, represented by larger baseline lumbar-thoracic AVT ratio, should be selected as UEV to prevent proximal decompensation. 4.