What happens to the unfused upper thoracic curve after posterior spinal fusion for adolescent idiopathic scoliosis?

OBJECTIVE Spontaneous lumbar curve correction after selective thoracic fusion in surgery for adolescent idiopathic scoliosis (AIS) is well described. However, only a few articles have described the course of the uninstrumented upper thoracic (UT) curve after fusion, and the majority involve a hybrid construct. In this study, the authors sought to determine the outcomes and associated factors of uninstrumented UT curves in patients with AIS. METHODS The authors retrospectively reviewed a prospectively collected multicenter AIS registry for all consecutive patients with Lenke type 1–4 curves with a 2-year minimum follow-up. UT curves were considered uninstrumented if the upper instrumented vertebra (UIV) did not extend above 1 level from the lower end vertebra of the UT curve. The authors defined progression as > 5°, and divided patients into two cohorts: those with improvement in the UT curve (IMP) and those without improvement in the UT curve (NO IMP). Radiographic, demographic, and Scoliosis Research Society (SRS)–22 survey outcome measures were compared using univariate analysis, and significant factors were compared using a multivariate regression model. RESULTS The study included 450 patients (370 females and 80 males). The UT curve self-corrected in 86% of patients (n = 385), there was no change in 14% (n = 65), and no patients worsened. Preoperatively, patients were similar with respect to Lenke classification (p = 0.44), age (p = 0.31), sex (p = 0.85), and Risser score (p = 0.14). The UT curves in the IMP group self-corrected from 24.7° ± 6.5° to 12.6° ± 5.9°, whereas in the NO IMP group UT curves remained the same, from 20.3° ± 5.8° to 18.5° ± 5.7°. In a multivariate analysis, preoperative main thoracic (MT) curve size (p = 0.004) and MT curve correction (p = 0.001) remained significant predictors of UT curve improvement. Greater correction of the MT curve and larger initial MT curve size were associated with greater likelihood of UT curve improvement. CONCLUSIONS Spontaneous UT curve correction occurred in the majority (86%) of unfused UT curves after MT curve correction in Lenke 1–4 curve types. The magnitude of preoperative MT curve size and postoperative MT curve correction were independent predictors of spontaneous UT curve correction.

Does Thoracic Kyphosis Have Any Importance in Selective Versus Nonselective Fusion Preference in Patients With Lenke Type 5C Adolescent Idiopathic Scoliosis? A Contribution to the Guidance of the Lenke Classification

BackgroundAlthough Lenke classification analyses the sagittal plane as (+), N, and (-), it does not consider it in the choice of treatment, and it has limitations with overall thoracic kyphosis (TK). To investigate the importance of TK for treatment preference in patients with Lenke 5C adolescent idiopathic scoliosis (AIS) by comparing radiological outcomes of the patients who underwent selective fusion (SF) or nonselective fusion (NSF). MethodsThirty-two patients with Lenke type 5C AIS were included and then divided into two groups as per the fusion procedure used in the surgical treatment. SF group including 17 patients (15 females; mean age = 16 years, age range, 14–21) with normal TK and NSF group including 15 patients (11 females; mean age = 17 years, age range, 13–26) with thoracic hyper-kyphosis. Thorocolumbar/lumbar (TL/L) Cobb, thoracic (T) Cobb, TK and lumbar lordosis (LL) were measured on standing spine radiographs preoperatively and at the final follow-up. The correction rates (CR) of each radiographic parameter were calculated.ResultsNo significant differences were observed in the mean CR of all radiographic parameters, except TK and LL correction rates. The mean CR of TK was significantly higher in NSF group (-17% [range, -100–69]) than in SF group (67% [range, 9–100]) (p = 0.000). Likewise, the mean CR of LL was found significantly higher in NSF group (12.47% [range, -100–51]) than in SF group (-2.41% [range, -75–47]) (p = 0.036).ConclusionIn patients in whom Lenke's sagittal modifier is N, SF can be performed efficiently. NSF should be preferred in those with Lenke's sagittal modifiers (+) as TK can be better controlled with NSF.Level of Evidence: 3

Sagittal profile modifications in hybrid versus all screw technique in adolescent idiopathic scoliosis

Aim of the study was to evaluate sagittal parameters modifications, with particular interest in thoracic kyphosis, in patients affected by adolescent idiopathic scoliosis (AIS) comparing hybrid and all-screws technique. From June 2010 to September 2018, 145 patients were enrolled. Evaluation included: Lenke classification, Risser scale, coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS). Patients were divided in two groups (1 all-screws and 2 hybrid); a further division, in both groups, was done considering preoperative TK values. Descriptive and inferential statistical analysis was conducted. 99 patients were in group 1, 46 in group 2 (mean follow-up 3.7 years). Patients with a normo-kyphotic profile developed a little variation in TK (Δ pre–post = 2.4° versus − 2.0° respectively). Hyper-kyphotic subgroups had a tendency of restoring a good sagittal alignment. Hypo-kyphotic subgroups, patients treated with all-screw implants developed a higher increase in TK mean Cobb angle (Δ pre–post = 10°) than the hybrid subgroup (Δ pre–post = 5.4°) (p = 0.01). All-screws group showed better results in restoring sagittal alignment in all subgroups compared to hybrid groups, especially in hypo-TK subgroup, with the important advantage to give better correction on coronal plane.

The Influence of Lumbar Modifiers on Functional and Radiological Outcomes in the Brace Treatment of Lenke Type 1 Adolescent Idiopathic Scoliosis

Background Brace treatment prevents the progression of scoliosis and reduces surgical treatment rates. However, the efficacy of brace treatment varies depending on the patientʼs age, gender, curve magnitude and type, structure of the curve, and patient compliance at the beginning of treatment. Methods Between January 2009 and April 2015, 106 Lenke type 1 AIS consecutive patients (69 females, 37 males) who were treated with a brace were examined in three groups according to Lenke classification lumbar modifiers. The patients were evaluated at pre-bracing and 1 and 2 years after bracing. The Scoliosis Research Society 22 (SRS-22) and Oswestry Disability Index (ODI) were used for functional evaluation. Radiological evaluation revealed the Cobb angle, thoracic kyphosis angle, lumbar lordosis angle, trunk shift, shoulder asymmetry, and body height difference. Results Functional and radiological evaluation showed a statistically significant improvement in Lenke 1A, 1B, and 1C at 1 and 2 years after bracing compared to the pre-bracing (p = 0.000, p = 0.000, and p = 0.000, respectively). Lenke 1C had the best ODI score and followed by decreasing values of 1B and 1A respectively (p = 0.009). Lenke 1B had the best SRS-22 score and the mean scores of 1A and 1C were equal (p = 0.017). There was no significant difference between the groups in the parameters other than the trunk shift in radiological evaluation (p = 0.043). Conclusions Significant improvement was observed in all types of lumbar modifiers at the end of the 2nd year compared to pre-bracing. The best improvement in the ODI score was in the 1C modifier, whereas the best improvement in the SRS-22 score was in the 1B modifier. The type of lumbar modifier should be directly taken into consideration before starting brace treatment in Lenke type 1 AIS. Level of evidence Level III, retrospective study

Choosing the Distal Fusion Levels in Lenke Type 1 Adolescent Idiopathic Scoliosis: How Do the Existing Classifications and Recommendations Guide Us?

Study Design: Retrospective cohort. Objective: ( a) To compare the recommendations of Lenke and Peking Union Medical College (PUMC) classifications in choosing distal fusion levels in Lenke 1 adolescent idiopathic scoliosis (AIS) curves and ( b) to analyze whether the variability in distal fusion levels influences treatment outcomes. Methods: Hospital records of Lenke 1 AIS patients operated for single stage, posterior-only deformity correction were analyzed. Distal fusion levels recommended by Lenke and PUMC classifications were calculated and were compared with the actual distal fusion levels. The study population was divided based on whether the actual distal fusion levels were in agreement, shorter or longer than those recommended by Lenke classification. Subgroup analysis of Lenke 1C curves was done. The groups were compared with regard to the following outcome measures: Cobb angle correction, postoperative sagittal vertical axis, postoperative C7 offset, and Scoliosis Research Society–22r (SRS-22r) score at 24 months. Results: The distal fusion levels recommended by the 2 classifications were in agreement in 92 of 104 cases. In all the cases with disparity, Lenke classification recommended shorter fusions than the PUMC classification. No statistically significant difference was observed in the outcome measures—whether the actual distal fusion levels were in agreement, shorter, or longer than those recommended by the Lenke classification or whether or not the recommendations for selective fusion of any of these classifications were adhered to. Conclusion: Lenke classification can save fusion levels without compromising on treatment outcomes when compared with PUMC classification. Variability in choice of distal fusion levels is not clinically significant at 24-month follow-up.

INTRAOBSERVER AND INTEROBSERVER RELIABILITY OF THE LENKE CLASSIFICATION AMONG SPINE SURGEONS

ABSTRACT Objective The objective of this study was to analyze the intraobserver and interobserver reliability of the Lenke classification among spine surgeons from the city of Salvador, Bahia. Methods Preoperative imaging (front, profile and lateral inclinations) examinations of 20 patients at the Outpatient Clinic of the of Santa Izabel Hospital Orthopedic Department, Salvador, Bahia, who had been diagnosed with adolescent idiopathic scoliosis, were selected to be evaluated by 15 spine surgeons two times at an interval of 30 days, for analysis of the intraobserver and interobserver reliability of the Lenke classification. The project was first submitted for ethical analysis to the Institutional Review Board of the Santa Izabel Hospital - Santa Casa de Misericórdia da Bahia / Prof. Dr. Celso Figueirôa and approved with voucher number 002650/2019. All the participants signed the Informed Consent Form (ICF). Results Analyzing the concordance using the Kappa index, interobserver reproducibilities of 0.755, 0.525 and 0.840 were obtained for the type of curve and the lumbar and sagittal modifiers, respectively, while the intraobserver reliabilities for the same parameters were 0.921, 0.370 and 0.929. Conclusion For the study population, the reliability of Lenke’s classification was moderate to almost perfect. Level of evidence III; Interobserver and intraobserver reliability.

LEG LENGTH DISCREPANCY IN ADOLESCENT IDIOPATHIC SCOLIOSIS

ABSTRACT Objective The objective of this study is to evaluate leg length discrepancy in adolescent idiopathic scoliosis. Methods A retrospective study of 80 subjects with adolescent idiopathic scoliosis (AIS) was conducted. The inclusion criteria were patients aged 10 to 18 years old with posteroanterior (PA) and lateral full-length radiographs. The exclusion criteria were patients subjected to surgery or orthotic treatment, those with other spinal disease, and those with poor quality x-rays. The parameters evaluated were: age, sex, Risser stage (RS), triradiate cartilage (TC), scoliotic curvatures, differentiated according to Lenke classification, sagittal (SB) and coronal balance (CB), and leg length discrepancy, which was assessed through the difference between the femoral heads (LLD) and through the assessment of pelvic obliquity (PO). Results The majority of patients with AIS demonstrated a mild LLD (<1 cm). The mean LLD was significantly different (p<0.01) between the scoliotic population with a main thoracolumbar curvature and those with a main lumbar curvature. When there was an LLD, it was the left limb that was shortened in most cases. The side of the longer lower limb had a direct influence on the CB (p=0.052). Conclusions This study demonstrates that in an AIS population with small LLD values, the extent of the shortening has a stronger impact on coronal balance and location than on the dimension of the main scoliotic curvature. These results demonstrate the importance of a more in-depth study on the effects of LLD <1 cm in the development of AIS and coronal imbalance. Level of evidence IV; Case Series.

ADOLESCENT IDIOPATHIC SCOLIOSIS AND SIMILAR CONDITIONS: THREE-DIMENSIONAL CLASSIFICATION

ABSTRACT Objective: To create a new comprehensive, three-dimensional, applicable classification for Adolescent Idiopathic Scoliosis and similar conditions. Methods: The Three-Dimensional Classification was created with three components: the first, the quantitative factor, divides into three types according to the number of curves; the second, the locator factor defines the most structured point of the curve; and the third, the sagittal factor, evaluates the overall sagittal plane. To test the new classification, we studied the images of 99 patients comparing the intra- and interobserver agreement and reproducibility index of the Three-Dimensional Classification with that of Lenke. Results: It can be stated that, overall, the agreement between the three evaluators in relation to the Three-Dimensional Classification and that of Lenke in this series was considered very good. Conclusions: The case study showed a significant difference in the percentages between the two Classifications. In the evaluation of thoracic kyphosis, the Three-Dimensional Classification defined 26.6% of the cases as hyperkyphosis and 61.6% as normal, whereas the Lenke Classification defined 6.06% as hyperkyphosis and 84.18% as normal. However, in the global comparative analysis of the methods, the Three-Dimensional and Lenke systems presented statistically the same levels of agreement, since the values of the confidence intervals overlap. Level of Evidence II; Retrospective study.