Postoperative Coronal Balance Research Articles

Usefulness of modified S-line for upper instrumented vertebra selection in adolescent idiopathic scoliosis Lenke type 1C curve.

Determine the effect of using the modified S-line vertebra (MSLV) as the upper instrumented vertebra (UIV) on postoperative trunk balance, L4 tilt, and clinical outcomes in selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS) Lenke type 1C curve. Twenty-eight consecutive patients (all female; mean age: 15.4±2.0 years) with AIS Lenke type 1C curve were retrospectively enrolled. Primary outcome measures were coronal balance (absolute distance between C7 and the center of the sacral vertical line), L4 tilt, and Scoliosis Research Society (SRS)-22r scores at 2 years postoperatively. The group with the MSLV at the UIV was designated as the MSLV group (18 patients), and the group with the MSLV proximal (12 patients) or distal (4 patients) to the UIV was defined as the non-MSLV group. We observed no significant differences between the groups regarding age, LIV and stable vertebra positioning, or preoperative X-ray parameters. Postoperative coronal balance was significantly better in the MSLV group (0.39±0.08 vs. 1.34±0.22 cm; P.

Risk Factors of Postoperative Coronal Balance Transition in Degenerative Lumbar Scoliosis.

Retrospective radiographic study. To determine the potential risk factors influencing the transition of postoperative coronal balance in degenerative lumbar scoliosis (DLS) patients. As time passes after surgery, the spinal sequence of DLS patients may dynamically shift from coronal balance to imbalance, causing clinical symptoms. However, the transition of postoperative coronal balance and its risk factors have not been effectively investigated. We included 156 DLS patients. The cohort was divided into immediate postoperative coronal balance with follow-up balance (N=73) and follow-up imbalance (N=21), immediate postoperative coronal imbalance with follow-up balance (N=23) and follow-up imbalance (N=39). Parameters included age, sex, classification of coronal balance, coronal balance distance, fusion of L5 or S1, location of apical vertebra, apical vertebral translation (AVT), Cobb angle of main curve and lumbar-sacral curve, tilt and direction of L4/5, tilt and direction of upper instrumented vertebra (UIV), and Cobb angle of T1-UIV. Statistical testing was performed using chi-square/Fisher's exact test, t-tests or non-parametric tests, correlation testing, and stepwise logistic regression. We identified a significant difference in preoperative AVT, preoperative Cobb angle, and immediate postoperative UIV tilt between patients with and without follow-up balance. Logistic regression analysis demonstrated factors associated with follow-up coronal imbalance included preoperative AVT (P=0.015), preoperative Cobb angle (P=0.002), tilt of immediate postoperative UIV (P=0.018). Factors associated with immediate postoperative coronal imbalance patients with follow-up coronal balance were sex, correction ratio of main curve, and direction of L4. Logistic regression analysis further identified a correction ratio of main curve≤0.7 (P=0.009) as an important predictive factor. Patients with immediate postoperative coronal balance and higher preoperative AVT, preoperative Cobb angle, and tilt of immediate postoperative UIV were more likely to experience follow-up coronal imbalance. A correction ratio of main curve≤0.7 was an independent predictor of follow-up coronal imbalance. 3.

Long-term Outcomes of Posterior Multilevel Crack Osteotomy: Revisional Surgery for Scoliosis With a Fusion Mass.

Osteotomies are required for the mobilization of spinal segments in patients with revisional scoliosis surgery with a fusion mass; however, only a few techniques have shown efficacy and safety, and their mid- and long-term outcomes remain unelucidated. This study aimed to analyze long-term outcomes of the posterior multilevel crack osteotomy (PMCO) technique for revisional surgery for scoliosis with a fusion mass. Data from 18 patients who underwent revisional scoliosis surgery using PMCO between 2009 and 2015 and had more than 5-year follow-up were retrospectively reviewed. The Cobb angle and coronal and sagittal balance parameters were examined preoperatively, postoperatively, and during the final follow-up. Perioperative parameters and complications were also assessed. Preoperative and postoperative Cobb angles were 60.5° and 29.9°, respectively (p < 0.001); this improvement was maintained until the final follow-up (33.4°, p = 0.058). The difference in preoperative and postoperative coronal balance was statistically significant (15.9 mm and 9.2 mm, respectively; p < 0.001); this was maintained until the final follow-up (p = 0.071). There was no change in sagittal balance parameters over the 3 measurement periods. Only 1 patient showed PMCO-related motor weakness, but he spontaneously recovered 3 months after postsurgery. Pseudarthrosis was not observed during the follow-up period. Incomplete osteotomy using PMCO provided satisfactory deformity correction without severe complications during revisional surgery for scoliosis with a fusion mass. It may be a less invasive procedure that maintains cortical continuity, preserves soft tissues, and provides sufficient mobility for the correction of spinal segments.

Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery.

The aim of the present study is to elucidate preoperative risk factors for inadequate correction of coronal imbalance and/or creation of new postoperative coronal imbalance (iatrogenic CIB) in patients who undergo surgery for Adult Spinal Deformity (ASD). A retrospective review of adults who underwent posterior spinal fusion (>5 levels) for ASD was performed. Patients were divided into groups according to the Nanjing classification: type A (CSVL < 3 cm), type B (CSVL > 3 cm and C7 plumb line shifted to major curve concavity), and type C (CSVL > 3 cm and C7 plumb line shifted to major curve convexity). They were also divided according to postoperative coronal balance in balanced (CB) vs. imbalanced (CIB) and according to iatrogenic coronal imbalance (iCIB). Preoperative, postoperative, and last follow-up radiographical parameters and intraoperative data were recorded. A multivariate analysis was performed to identify independent risk factors for CIB. A total of 127 patients were included (85 type A, 30 type B, 12 type C). They all underwent long (average levels fused 13.3 ± 2.7) all-posterior fusion. Type C patients were more at risk of developing postoperative CIB (p = 0.04). Multivariate regression analysis indicated L5 tilt angle as a preoperative risk factor for CIB (p = 0.007) and indicated L5 tilt angle and age as a preoperative independent risk factors for iatrogenic CIB (p = 0.01 and p = 0.008). Patients with a preoperative trunk shift towards the convexity of the main curve (type C) are more prone to postoperative CIB and leveling the L4 and L5 vertebrae is the key to achieve coronal alignment preventing the "takeoff phenomenon".

Risk factors and clinical impact of persistent coronal imbalance after posterior spinal fusion in thoracolumbar/lumbar idiopathic scoliosis.

Persistent coronal imbalance (PCI) can develop postoperatively. In this study, the authors aimed to clarify the risk factors and clinical impact of PCI after posterior spinal fusion (PSF) in idiopathic scoliosis (IS) patients with a major thoracolumbar/lumbar (TL/L) curve. Data on 108 patients with Lenke type 5C or 6C IS who underwent PSF with a minimum of 2 years of follow-up were retrospectively analyzed. PCI was defined as coronal imbalance persisting 2 years after surgery. Radiographic parameters and clinical outcomes were compared between the PCI (+) and PCI (-) groups. Multivariate regression analyses of associated factors were performed to determine the risk factors for PCI. Of the 108 patients, 48 (44%) had immediate postoperative coronal imbalance, and 10 of these patients (9%) had coronal imbalance persisting 2 years after surgery. The PCI (+) group had significantly worse postoperative subtotal and satisfaction scores than the PCI (-) group. Preoperative apical vertebral translation (AVT) of the TL/L curve (AVT-TL/L) and postoperative coronal balance (CB) were identified as independent risk factors for PCI. The cutoff values of preoperative AVT-TL/L at 49.5 mm (area under the curve [AUC] 0.835, p = 0.001, 95% CI 0.728-0.941, sensitivity 70.0%, specificity 72.4%) and those of postoperative CB at -27.5 mm (AUC 0.837, p < 0.001, 95% CI 0.729-0.945, sensitivity 78.6%, specificity 70.0%) were used to predict PCI. In selective fusion cases, older age (OR 2.110, 95% CI 1.159-3.842, p = 0.015), greater preoperative AVT-TL/L (OR 1.199, 95% CI 1.029-1.398, p = 0.020), and less postoperative CB (OR 0.855, 95% CI 0.743-0.983, p = 0.027) were independent risk factors for PCI. Preoperative AVT-TL/L and postoperative CB are important parameters for predicting PCI. PCI adversely affects postoperative clinical outcomes. In selective fusion surgery, PCI tends to occur in older patients due to reduced flexibility and compensatory abilities.

Matching correction of main and compensatory curves is critical for immediate postoperative coronal balance in correction of severe adult idiopathic scoliosis.

To analyze the correlation between immediate postoperative coronal imbalance and the matching degree of the correction rates of the main curve and compensatory curves in the surgical treatment of severe adult idiopathic scoliosis. Patients were categorized into three types based on the preoperative coronal balance status (type A = balance, type B = shifted to cave side and type C = shifted to convex side), and each type was further divided into two subgroups based on the postoperative coronal balance status (balance and imbalance). Different coronal parameters before and after operations were calculated and compared. The rate of postoperative CIB was highest in type C patients (53.8%) and lowest in type A patients (31.5%). To avoid postoperative CIB, the value of the postoperative CRmain should fall within the range of 1.001 × CRcomp ± 2.84% in type A patients, 1.112 × CRcomp + 3.3% ± 5.02% in type B patients and 0.907 × CRcomp - 2.5% ± 4.38% in type C patients. Mismatch between the correction rates of the main curve and compensation curves is a critical cause of immediate postoperative CIB. The relatively equal correction of the main curve and compensatory curves is essential for type A patients to achieve postoperative coronal balance, while the correction rate of the main curve should be higher than the compensatory curves in type B patients and vice versa in type C patients. Three formulas for the three different types were developed to provide helpful guidance information for surgical planning.

Radiographic Coronal Imbalance and Shoulder Asymmetry Continue to Improve Between 2 and 5 Years Following Surgery of Adolescent Idiopathic Scoliosis.

Managing patients with coronal imbalance (CI) and shoulder height asymmetry following scoliosis surgery can be challenging. Little is known about the course of findings over time and whether they improve or persist. The aim was to report the rate of suboptimal radiographic CI or shoulder asymmetry (SA) at 5 years in patients who were already reported to have CI or SA 2 years after surgery for adolescent idiopathic scoliosis (AIS). An AIS database was reviewed for patients with both 2- and 5-year follow-up after surgery. From this cohort, patients with CI>2 cm or SA>2 cm at their 2-year follow-up were identified and reevaluated, using the same parameters, at 5-year follow-up. Of 916 patients, 157 (17%) patients had CI and 69 (8%) patients had SA at 2-year follow-up. At 5 years this improved to 53 (6%) and 11 patients (1%), respectively. Having coronal or shoulder imbalance 2 years after surgery for AIS does not guarantee continued imbalance 5 years after surgery. Most patients demonstrate some improvement in these measures of clinical deformity. Anticipating the potential course following a postoperative coronal balance and shoulder height differences can help surgeons manage and counsel their patients appropriately. Level II-therapeutic.

Intra operative assessment of the coronal balance in spinal deformity surgery : a technical note and retrospective study

Obtaining a spine that is well balanced after fusion for scoliotic deformity is primordial for the patients' quality of life. A simple T-shaped instrument combined with standard intraoperative fluoroscopy can be of great help to evaluate the coronal alignment quickly. The aim of this study was to evaluate if a T-shaped device could predict the postoperative coronal balance. Before finalization of the rod fixation, the balance was checked by verifying the relationship between the T-shaped instrument and the upper instrumented vertebra (UIV), and final adjustments were made to correct the coronal balance. A retrospective study was conducted on 48 patients who underwent surgery to correct scoliotic deformity. Intraoperative and postoperative coronal alignment was measured independently by two observers. The mean intraoperative horizontal offset measured between T-shaped instrument and the center of the UIV was 1,69mm to the right with a standard deviation (SD) of 12,43 mm. On postoperative full spine radiographs, the mean offset between the centra sacral vertical line and the center of the UIV was 2,44mm to the left with a SD of 13,10mm. There is no significant difference in coronal balance between both measurements (p=0,12). With this technique we were able to predict the postoperative coronal balance in all but one patient (97,92%). We conclude that the use of a simple T-shaped instrument can provide adequate intraoperative assessment of coronal balance in correcting scoliotic deformity. Level of evidence : IV - case series.

A novel integrated global coronal aligner helps prevent post-operative standing coronal imbalance in adult spinal deformity patients fused to pelvis: technical notes and preliminary results

BackgroundChieving postoperative coronal balance in adult spinal deformity correction surgeries can be challenging. Even with T square rod technique, there were still some cases with good intraoperative coronal alignment but unsatisfactory post-operative standing coronal imbalance. Thus, the novel techniques to obtain global coronal balance are still in great needs. The purpose of this study was to describe a novel integrated global coronal aligner (IGCA) and evaluate its efficacy on avoidance of post-operative coronal imbalance in adult spinal deformity patients fused to pelvis.MethodsA detailed description of IGCA technique was presented. 52 ASD patients fused to pelvis were divided into two groups (IGCA group, n = 27; and non-IGCA group, n = 25) according to whether intraoperative IGCA was used or not. Preoperative demographics and postoperative outcomes were compared.ResultsThere were no significant differences regarding coronal balance difference (CBD) and imbalance/balance ratio between IGCA and non-IGCA groups preoperatively. After surgery, CBD in IGCA group was significantly improved from 24.7 ± 20.3 mm preoperatively to 12.6 ± 6.4 mm postoperatively (t = 3.185 p = 0.004), and imbalance/balance ratio decreased significantly from 55.6% (15/27) preoperatively to 11.1% (3/27) postoperatively (χ2 = 12.000, p = 0.001), while CBD and imbalance/balance ratio in non-IGCA group were not significantly improved. Compared to non-IGCA group, the amount of correction in CBD was significantly larger in IGCA group (t = 3.274, P = 0.002), and imbalance/balance ratio in IGCA group was significantly lowered (χ2 = 8.606 p = 0.003). Further logistic regression analysis revealed IGCA technique was associated with increased odds ratio for postoperative coronal balance (odds ratio: 7.385; 95% confidence interval 1.760–30.980; P = 0.006).ConclusionsThe novel intraoperative IGCA technique could help improve CBD and reduce imbalance/balance ratio. It could help prevent post-operative coronal imbalance in adult spinal deformity patients fused to pelvis.Level of evidence3

What determines immediate postoperative coronal balance and delayed global coronal balance after anterior spinal fusion for Lenke 5C curves?

To determine the factors associated with 6-week postoperative global coronal balance and delayed global coronal balance at 2-year follow-up after anterior spinal fusion for Lenke 5C curves. A total of 124 consecutive Lenke 5C curves with minimum 2-year follow-up was studied. Radiographic parameters were studied preoperatively, 6 weeks postoperatively, and 2years postoperatively. Coronal balance was measured by C7-CSVL and trunk shift < 20mm. The study outcomes were patients with early coronal balance and those who had immediate imbalance but developed delayed balance. Multivariate regression analyses of associated factors were performed with cutoffs determined by receiver operating characteristic curve. 31.5% patients attained global coronal balance immediate postoperatively and 89.4% of the early imbalance cases showed spontaneous coronal balance at 2-year follow-up. Increased preoperative UIV tilt (OR 1.093; p = 0.026; 95% CI: 1.011-1.182) and reduced immediate postoperative RSH difference (OR 0.963; p = 0.015; 95% CI: 0.935-0.993) were associated with immediate postoperative balance. For those with immediate imbalance, larger preoperative major Cobb angle (OR 1.226; p = 0.047; 95% CI: 1.003-1.499), less preoperative C7-CSVL (OR 0.829; p = 0.016; 95% CI: 0.712-0.966), and less immediate postoperative LIV tilt (OR 0.728; p = 0.013; 95% CI: 0.567-0.934) were associated with 2-year coronal balance. There was significant improvement in function (p = 0.006), self-image (p = 0.039) and total score domains (p = 0.014) in immediate imbalance to 2-year balance and imbalance groups. Successful balance is achieved with a parallel fusion mass when performing anterior spinal fusion for Lenke 5C curves. Patients should be reassured that most attain eventual coronal balance despite the early imbalance. Level of evidence Therapeutic III.

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.

Postoperative neck tilt in Lenke 1 and 2 AIS patients after correction surgery: a novel predictive index

BackgroundPostoperative neck tilt (PNT) is a phenomenon in adolescent idiopathic scoliosis (AIS) patients which is distinct form shoulder imbalance. There were scarce studies performed to explore the risk factors for PNT in Lenke 1 and 2 AIS patients, and whether it can be predicted after surgery remains unknown. The objective of this study is to explore the prevalence and risk factors for PNT, and introduce an index for prediction of PNT in Lenke 1 and 2 AIS patients after correction surgery.MethodsMedical records of Lenke 1 and 2 AIS patients who received correction surgery were reviewed from February 2013 to February 2015. Posteroanterior films were evaluated before surgery and at 2 years’ follow-up. Patients were divided into two groups according to whether PNT occurred at the 2 years’ follow-up. Risk factors of PNT were analyzed, and PNT Index was proposed and verified.ResultsOne hundred two Lenke 1 and 2 AIS patients were recruited in this study. The prevalence of PNT after correction was 40.2%. According to the postoperative CAT (Cervical Axis Tilt), patients were divided into two group: PNT group (CAT≧5°, n = 41) and non-PNT group (CAT< 5°, n = 61). Postoperative T1 tilt, preoperative proximal thoracic curve (PTC), postoperative PTC and postoperative coronal balance (CB) were significantly different between two groups. Logistic regression showed that postoperative PTC and postoperative CB were the primary risk factors for PNT, which could be predicted by the regression equation: PNT Index = 1.1 x postoperative PTC (degrees) - 0.9 x postoperative CB (millimeters). On the basis of ROC curve, if PNT Index was more than 10, the occurrence rate of PNT was 86%. On the contrary, the rate of no PNT phenomenon was 80%.ConclusionPostoperative PTC and postoperative CB were the important factors for PNT in Lenke 1 and 2 AIS patients. Sufficient correction of PTC and moderate correction of CB should be recommended when operating on Lenke1 and 2 AIS patients.

Risk Factors for Postoperative Coronal Balance in Adult Spinal Deformity Surgery.

Study Design:A retrospective case-control study.Objectives:To determine factors influencing the ability to achieve coronal balance following spinal deformity surgery.Methods:Following institutional ethics approval, the radiographs of 47 patients treated for spinal deformity surgery with long fusions to the pelvis, were retrospectively reviewed. The postoperative measurements included coronal balance, L4 tilt, and L5 tilt, levels fused, apical vertebral translation and maximum Cobb angle. L4 and L5 tilt angles were measured between the superior endplate and the horizontal. Sagittal parameters including thoracic kyphosis, lumbar lordosis, pelvic incidence, and sagittal vertical axis were recorded. Coronal balance was defined as the distance between the central sacral line and the mid body of C7 being ≤40 mm. Surgical factors, including levels fused, use of iliac fixation with and without connectors, use of S2A1 screws, interbody devices, and osteotomies. Statistical tests were performed to determine factors that contribute to postoperative coronal imbalance.Results:Of the 47 patients reviewed, 32 were balanced after surgery and 14 were imbalanced. Coronal balance was 1.30 cm from center in the balanced group compared to 4.83 cm in the imbalanced group (P < .01). Both L4 and L5 tilt were statistically different between the groups. Gender and the use of transverse connectors differed between the groups but not statistically.Conclusions:In adult spinal deformity patients undergoing primary fusions to the pelvis, the ability to level the coronal tilt of L4 and L5 had the greatest impact on the ability to achieve coronal balance in this small series. A larger prospective series can help validate this important finding.

Radiological factors affecting post-operative global coronal balance in Lenke 5 C scoliosis.

Lenke 5 C curves are frequently associated with clinically and radiological coronal imbalance. Appropriate selection of proximal and distal levels of fusion is essential to ensure good coronal balance (CB). We aimed to evaluate radiological factors associated with (I) global CB in the early post-operative period; (II) late decompensation of CB; and (III) favourable spontaneous correction of CB on long term follow up. Twenty-three Lenke type 5C scoliosis cases treated with selective posterior lumbar instrumentation were retrospectively evaluated. Pre-operative, early post-operative and late post-operative (>2 years) whole length radiographs were analysed. Cobb's angle, lumbar lordosis, coronal imbalance, lower instrumented vertebra (LIV) tilt and translation and upper instrumented vertebra (UIV) tilt and translation were measured. The proximal and distal fusion levels were noted and correlated with post-operative CB. There were 21 females and 2 males with a mean follow up of 36 months. The mean pre-operative cobb angle was 55°±13.26°, which corrected to 14.7°±8.84° and was maintained on follow up. Eight patients had early post-operative coronal imbalance with spontaneous resolution seen in six cases on long term follow-up. At final follow-up, four cases had coronal imbalance (persistent imbalance since early post-operative period =2; late decompensation =2). In cases with early imbalance 5/8 cases had a pre-operative LIV tilt of ≥25°. All four patients with coronal imbalance at final follow-up had pre-operative LIV tilt ≥25°. Radiographic parameters which correlated with post-operative coronal imbalance were pre-operative LIV tilt (r=0.64, P=0.001), pre-operative LIV translation (r=0.696, P<0.001), pre-operative UIV translation (r=0.44, P=0.030), post-operative LIV tilt (r=0.804, P<0.001), and post-operative UIV tilt (r=0.62, P=0.001). In Lenke 5C scoliosis, a pre-operative LIV tilt ≥25° significantly correlates with post-operative global coronal imbalance. Increasing UIV tilt may be a factor that accounts for improvement of CB in late follow-up period.

Onset and remodeling of coronal imbalance after selective posterior thoracic fusion for Lenke 1C and 2C adolescent idiopathic scoliosis (a pilot study)

BackgroundPostoperative coronal imbalance is a significant problem after selective thoracic fusion for primary thoracic and compensatory lumbar curves in adolescent idiopathic scoliosis (AIS). However, longitudinal studies on postoperative behavior of coronal balance are lacking. This multicenter retrospective study was conducted to analyze factors related to onset and remodeling of postoperative coronal imbalance after posterior thoracic fusion for Lenke 1C and 2C AIS.MethodsTwenty-one Lenke 1C or 2C AIS patients, who underwent posterior thoracic fusion ending at L3 or above, were included with a minimum 2-year follow-up. The mean patients’ age was 15.1 years at the time of surgery. Radiographic measurements were performed on Cobb angles of the main thoracic (MT) and thoracolumbar/lumbar (TLL) curves and coronal balance. Factors related to the onset of immediately postoperative coronal decompensation (IPCD) and postoperative coronal balance remodeling (PCBR), defined as an improvement of coronal balance during postoperative follow-up, were investigated using comparative and correlation analyses.ResultsMean Cobb angles for the MT and TLL curves were 57.3° and 42.3° preoperatively and were corrected to 22.8° and 22.5° at final follow-up, respectively. Mean preoperative coronal balance of −3.8 mm got worse to −21.2 mm postoperatively, and regained to −12.0 mm at final follow-up. Coronal decompensation was observed in two patients preoperatively, in ten patients immediately postoperatively, and in three patients at final follow-up. The preoperative coronal balance and lowest instrumented vertebra (LIV) selection relative to stable vertebra (SV) were significantly different between patients with IPCD and those without. PCBR had significantly negative correlation with immediately postoperative coronal balance.ConclusionsIPCD after posterior thoracic fusion for Lenke 1C and 2C AIS was frequent and associated with preoperative coronal balance and LIV selection. However, most patients with IPCD regained coronal balance through PCBR, which was significantly associated with immediately postoperative coronal balance. A fixation more distal to SV shifted the coronal balance further to the left postoperatively.

Lumbosacral-levelization during surgery reduce the risk of post-operative coronal imbalance in degenerative lumbar scoliosis after long spinal fusion

Objective To evaluate the postoperative coronal balance and clinical outcomes of transforaminal lumbar interbody fusion (TLIF) at convex side utilized in adult degenerative lumbar scoliosis (DLS) patients with coronal imbalance type C (C7PL shifted to the convex side for more than 3 cm). Methods All of 27 patients (2 males and 25 females) receiving posterior long spinal segment fusion surgery (5 or more segments involved) from June 2006 to June 2015 were retrospectively reviewed. The average age of the cohort was (62.11±8.22) years, (range, 50-76 years). 11 patients underwent to a transforaminal lumbar inter-body fusion (TLIF) at convex side of fractional curve procedure, while 16 had only long fusion. The coronal parameters including Cobb angle and distance between C7 plumb line and center sacral vertical line (C7PL-CSVL), as well as oblique angle of L4, L5, S1 and fusion level of L4, 5, L5S1 were measured preoperatively, postoperatively and last follow up. The Short Form-36 Health Survey (SF-36), Oswestry dability index(ODI), visual analogue scale(VAS) were assessed at pre-operation, post-operation and follow up. Clinical and radiographic parameters were compared between the two groups. Results The average follow up period was (51±11) months(24-120 months). The preoperative Cobb angles were 41.9°±10.7°. Two groups of patients had similar preoperative and postoperative lumbar curve correction; there was no significant differences in SVA (sagittal vertical axis) between two groups. Preoperative L 4,5 or L 5S1 tilt existed in all two groups of patients. After surgery, there were significant differences in correction of L 5S1 tilt (LIV=L5, 2.1 ° and 8.1 °±3.7 °, LIV=S1, 3.8 °±2.4 ° and 8.1 °±2.9 °, LIV=S2, 3.1 °±2.8 ° and 8.7 °±3.9 °) in DLS patients with TLIF, and patients in TLIF group had better preservation of correction than those in no TLIF group at final follow-up. Coronal balance distance (coronal balance distance, CBD) of TLIF group at final follow-up was significantly less than no TLIF group (1.8 ± 0.9 cm and 2.5 ±1.5 cm). Patients in TLIF group had a significantly higher fusion rate (100%, 11/11 and 93.75%, 15/16) and less postoperative complications than those from no TLIF group. Conclusion Performing TLIF at convex side could even the lumbar-sacral junction, promote the fusion process, and reduce the risk of postoperative coronal imbalance in preoperative coronal imbalance type C DLS patients. Key words: Lumbar vertebrae; Scoliosis; Adult; Spinal fusion

Coronal balance in idiopathic scoliosis: a radiological study after posterior fusion of thoracolumbar/lumbar curves (Lenke 5 or 6).

To explore the compensation mechanisms of immediate postoperative coronal imbalance (CIB) and identify the correlation between preoperative lumbosacral obliquity and postoperative CIB in patients with Lenke 5/6 adolescent idiopathic scoliosis (AIS) during a 2-year follow-up period. Medical records of patients with Lenke 5/6 AIS who were admitted in our hospital between Jan. 2008 and Jan. 2013 were reviewed retrospectively. General information of the patients including gender, age, and Risser classification was collected. Patients were divided into coronal balance (CB) and CIB groups according to the postoperative CB. Radiographic assessment included preoperative, postoperative and full-length anteroposterior and lateral radiographs and passive lateral bending radiographs of the spine at the last follow-up. Altogether 80 patients (37 in CIB group and 43 in CB group) were included in this study, of whom 27 patients in CIB group achieved balance at the last follow-up. Binary logistic regression showed that preoperative bending L5 tilt (OR=1.498) was a potential risk factor of postoperative CIB (p<0.05). Pearson correlation analysis showed that the distal wedge angle was significantly associated with immediate postoperative CB. Preoperative L5 tilt on bending radiographs was an important risk factor of postoperative CIB in Lenke 5/6 AIS, which might be compensated by the way similar to that seen in the Lenke 1 distal adding-on phenomenon. Appropriate shortening of the fusion segments may help reduce the occurrence of postoperative CIB in patients with a relatively large L5 tilt on the postoperative bending radiograph.

The Surgical Overcorrection of Lenke Type 1 Deformities with Selective Fusion Segments: What Happens to the Coronal Balance?

PurposeThe aim of our study is to determine the alterations on coronal balance after overcorrection of Lenke type 1 curve, retrospectively.MethodsDatas of 34 patients (29 female, 5 male patients; mean age, 16.3±3.3 years; range, 13-24 years) surgically treated for scoliosis between 2004 and 2010 were reviewed, retrospectively. The adolescent idiopathic scoliosis patients with Lenke type 1 curve treated with only posterior pedicle screw and postoperative thoracic curves less than 10° by Cobb method on frontal plane were enrolled in this study. Mean follow-up period was 52.5±29.7 months.ResultsThe mean amount of the preoperative thoracic curves was measured as 41.2°±6.1° (range, 30°-56°). The mean amount of the early postoperative thoracic curves was measured as 6.5°±1.8° (range, 3°-9°). The mean amount of the thoracic curves was measured as 8.5°±4.6° (range, 3°-22°) during the last follow-up (p=0.01). The mean preoperative coronal balance was measured as 8.5mm(range, 1-30mm). The mean early postoperative coronal balance was measured as 3.5mm(range, 0-36 mm). The mean coronal balance was measured as 5.5mm(range, 0-38mm) during the last follow-up (p>0.05).ConclusionWe suggest that Lenke type 1B and 1C should be carefully evaluated and the fusion levels should be accurately selected in order to maintain the correction of coronal balance. We suggest that selective fusion with overcorrection in Lenke type 1A are applied to curves that can be corrected lumbar curve at the preoperative bending radiograph and curves that not have coronal decompensation and >10° distal junctional kyphosis, preoperatively.

Selective versus nonselective thoracic fusion in Lenke 1C curves: a meta-analysis of baseline characteristics and postoperative outcomes.

Lenke 1C curves are challenging to manage surgically due to the structural thoracic deformity and nonstructural lumbar curve. Selective thoracic fusion (STF) is considered the standard of care because it preserves motion of the lumbar segment, yet nonselective STF (NSTF) remains prevalent. This study aims to identify baseline patient characteristics that drive treatment and to compare postoperative outcomes for both procedures. Studies that compared baseline and postoperative demographic data, health-related quality of life (HRQL) questionnaires, and radiographic parameters of patients with Lenke 1C curves undergoing STF or NSTF were identified for meta-analysis. The effect measure is expressed as a mean difference (MD) with 95% CI. A positive MD signifies a greater STF value, or a mean increase within the group. One prospective and 6 retrospective case-control studies with sample size of 488 patients (344 STF and 144 NSTF) were identified. Baseline age, sex, and HRQLs were equivalent, except for better scores in the STF group for the Scoliosis Appearance Questionnaire (SAQ): Unrelated to Deformity item (3.47 vs 3.88, p = 0.01) and the Spine Research Society questionnaire, Item 22: Pain (4.13 vs 3.92, p = 0.04). Radiographic findings were significantly worse in NSTF, as measured by the thoracolumbar/lumbar (TL/L) Cobb angle (MD: -4.29°, p < 0.01) and TL/L apical vertebral translation (AVT) (MD: -6.08, p < 0.01). Radiographic findings significantly improved in STF, as measured in the main thoracic (MT) Cobb angle (MD: -27.78°, p < 0.01), TL/L Cobb angle (MD: -16.24°, p < 0.01), MT:TL/L Cobb ratio (MD: -0.21, p < 0.01), coronal balance (MD: 0.47, p = 0.02), and thoracic kyphosis (MD: 7.87°, p < 0.01); and in NSTF in proximal thoracic (PT) Cobb angle (24° vs 14.1°, p < 0.01), MT Cobb angle (53.5° vs 20.5°, p < 0.01), and TL/L Cobb angle (41.6° vs 16.6°, p < 0.01). Postoperative TL/L Cobb angle (23.1° vs 16.6°, p < 0.01) was significantly higher in STF; but PT Cobb angle, MT Cobb angle, and MT:TL/L Cobb ratio are equivalent. Patients with larger lumbar compensatory curves displaying a larger degree of coronal translation, as measured by the TL/L AVT, are more likely to undergo an NSTF. Contrary to established guidelines, larger MT curve magnitudes and MT:TL/L Cobb angle ratios have not been found to influence the decision to pursue a selective thoracic fusion. Although overall both STF and NSTF groups are found to have effective postoperative coronal balance, the STF group has only modest improvements in the lumbar curve position as determined by a relatively unchanged TL/L AVT. Furthermore, surgeons may prefer NSTF in patients who may have a worse overall perception of their spinal deformity as measured by HRQL measures of pain and desire for appearance change.