Correction Of Proximal Thoracic Curve Research Articles

Can We Control Lateral Shoulder Balance Through Proximal Thoracic Curve Correction in Lenke Type 2 Adolescent Idiopathic Scoliosis?

Proximal thoracic curve (PTC) correction has been considered to prevent lateral shoulder imbalance in Lenke Type 2 adolescent idiopathic scoliosis (AIS) patients; however, postoperative shoulder imbalance (PSI) commonly occurs despite these strategies with PTC correction. We investigated the hypothesis that PTC correction would not directly affect PSI in the majority of Lenke type 2 AIS cases. Furthermore, we investigated the risk factors for lateral PSI after corrective surgery. This study examined the records for AIS patients with Lenke type 2 who underwent corrective surgery and followed up for >2 years. Patients were categorized into PSI (-); radiologic shoulder height (RSH)<15mm, and PSI (+); RSH≥15mm. Repeated measures analysis of variance was performed at preoperatively, postoperatively, 1 month, and final follow-up. Postoperative lateral shoulder imbalance was predicted by the identification of univariate analysis and multivariate analysis. Among the 151 patients reviewed, 29 (19.2%) showed PSI at final follow-up. Lateral shoulder balance parameters showed different directionalities between PSI (-) and (+) groups at postoperatively, 1 month, and final follow-up (P<0.01 each). Preoperative PTC, middle thoracic curve (MTC) curve and MTC correction showed strong correlations with the RSH (P=0.01, 0.03, and 0.04, respectively). However, PTC correction did not show a significant correlation with the RSH. Moreover, only a smaller MTC curve and larger MTC correction rate were related to lateral PSI in multivariate analysis. In Lenke type 2 AIS curves, the MTC curve and its correction predominantly influence lateral shoulder imbalance after corrective surgery, irrespective of the PTC correction extent. Consequently, overemphasizing the correction of the PTC curve may not necessarily lead to an improved lateral shoulder balance. When MTC curve is smaller, surgeons should be more careful for MCT overcorrection leading to a lateral shoulder imbalance. Level III.

The amount of proximal thoracic curve correction may not affect postoperative right shoulder depression in Lenke type 2 adolescent idiopathic scoliosis

The amount of proximal thoracic curve correction may not affect postoperative right shoulder depression in Lenke type 2 adolescent idiopathic scoliosis

The Importance of the Pedicle Diameters at the Proximal Thoracic Vertebrae for the Correction of Proximal Thoracic Curve in Asian Patients With Idiopathic Scoliosis.

A retrospective comparative radiographic study. The purpose of this study was to evaluate differences in the pedicle diameters of proximal thoracic vertebrae in relation to the severity of the proximal thoracic curve in Asian patients with idiopathic scoliosis. A small pedicle diameter at the proximal thoracic vertebra has been reported in normal population, but the changes of pedicle diameter in patients with a proximal thoracic curve have not been properly evaluated. One hundred eighty-two patients with adolescent idiopathic scoliosis involving a greater than 10-degree proximal thoracic curve were analyzed. Sixty-nine and 113 patients had a structural and nonstructural proximal thoracic curve, respectively. The pedicle width was evaluated from T1 to T4 using a reconstructed computed tomography (CT) scan. The pedicle widths were compared between the convex and concave side, and between the structural and nonstructural proximal thoracic curve groups. The pedicle widths at T3 (0.76 ± 0.92 mm) and T4 (0.50 ± 0.69 mm) on the concave side for the structural proximal thoracic curves were extremely narrow compared with those for the nonstructural proximal thoracic curves (T3,1.17 ± 0.84 mm; T4,0.82 ± 0.72 mm) (P = 0.002, 0.003, respectively). However, the T2 pedicle width was comparable on the concave side in both groups (2.44 ± 0.94 mm for the nonstructural and 2.32 ± 0.97 mm for the structural proximal thoracic curve, P = 0.430). A pedicle screw insertion at the T3 or T4 vertebra on the concave side is not always possible in cases of a structural proximal thoracic curve; however, the pedicle width of the T2 vertebra is very wide and safe for the standard pedicle screw insertion. These results should be considered when the surgeon decides the upper instrumented vertebra or the correction method for the structural proximal thoracic curve. 3.

Does fusion to T2 compared with T3/T4 lead to improved shoulder balance in adolescent idiopathic scoliosis with a double thoracic curve?

Proximal fusion level selection in adolescent idiopathic scoliosis (AIS) with a double thoracic curve (Lenke-2) remains debatable. The aim of this study was to compare the radiological outcomes of corrective surgery for Lenke-2 AIS according to the upper instrumented vertebra (UIV). This study included 74 patients who underwent corrective surgery for Lenke-2 AIS with the right main thoracic and left proximal thoracic (PT) curve at a single center. Various radiological parameters were measured using whole-spine standing radiographs preoperatively and postoperatively. Patients were grouped by proximal fusion level: T2 (group F; fusion, N=15) or T3/T4 (group NF; nonfusion, N=59). Preoperative and postoperative radiological parameters were compared between the two groups. Group NF was divided on the basis of the existence of a postoperative shoulder imbalance (PSI; >15 mm) and a subgroup analysis was carried out. PT curve correction rate (58.5 vs. 46.3%, P=0.005), right shoulder depression (4.3 vs. 10.3 mm, P=0.020), and proximal adjacent wedging (1.1 vs. 3.5°, P<0.001) were different between groups F and NF postoperatively. In the subgroup analysis, the Risser grade (3.9 vs. 2.8, P=0.009) and the main thoracic curve flexibility (53.5 vs. 42.6%, P=0.038) were different between the PSI positive and the PSI negative group when T3 or T4 was chosen as the UIV in Lenke-2 AIS. If T2 is selected as the UIV in patients with Lenke-2 AIS, more PT curve correction, less right shoulder depression, and less adjacent disc wedging can be anticipated. If T3 or T4 is chosen as the UIV, then right shoulder depression can be a problem postoperatively. Greater skeletal maturity and higher flexibility of the main thoracic curve might be preoperative risk factors for PSI. Thus, extension of the proximal fusion to T2 can be considered if the patient shows greater skeletal maturation and more flexible main thoracic curve to prevent PSI in Lenke-2 AIS with the right main thoracic and left PT curve.

Shoulder Balance and Scoliosis: The Unresolved Issue

Background Data: The main indication of surgery in patients with AIS is better function and cosmesis. Shoulder balance should be considered amongst cosmetic parameters that are strongly associated with patient satisfaction after surgery in patients with AIS. Proper correction of the main and proximal thoracic curves in conjunction with horizontalization of upper instrumented vertebra (UIV) is supposed to promote shoulder balance. In other words, better correction of radiological parameters should promote clinical shoulder balance; however, this is not always observed.Purpose: Determining which of the following radiological measures correlate significantly with postoperative clinical shoulder balance: T1 tilt, UIV tilt, clavicle rib intersection angle, and degree of proximal thoracic curve correction.Study Design: Retrospective clinical case cohort study.Patients and Methods: The study included 20 patients of AIS operated for correction by pedicle screw instrumentation. There were 13 females and 7 males. The mean age at the time of surgery was 14±2.4 years with a range from 11 to 18 years. Mean preoperative Cobb angle of the major curve was 76.1±21.7° corrected to a mean postoperative Cobb 28.2±14.2°. Correction percentage of the major curve was 63.1±14.2%. The data obtained from high resolution back view photographs (to assess clinical shoulder balance) and whole spine X-ray films taken within the first year of follow-up period (to assess radiological measures related to shoulder balance) were retrospectively evaluated. Outcome measures: clinical shoulder balance was correlated with 4 radiological parameters, namely, proximal thoracic curve correction percentage, T1 tilt, UIV tilt, and clavicle-rib intersection angle. Measurements were done by Surgimap software version 2.2.12 (Nemaris, Inc.,US, https://www.surgimap.com).Results: A weak positive correlation was found between postoperative shoulder balance and UIV tilt (r)=0.242, P=0.305, and a very weak negative correlation was found between postoperative shoulder balance and proximal thoracic curve correction percentage (r)=-0.027, P=0.910. A moderate positive correlation but statistically nonsignificant was found between postoperative shoulder balance and T1 tilt (r)=0.440, P=0.052, and a statistically significant positive correlation was found between shoulder balance and clavicle rib intersection angle (r)=0.567, P=0.009.

Do Current Recommendations for Upper Instrumented Vertebra Predict Shoulder Imbalance? An Attempted Validation of Level Selection for Adolescent Idiopathic Scoliosis.

Shoulder balance for adolescent idiopathic scoliosis (AIS) patients is associated with patient satisfaction and self-image. However, few validated systems exist for selecting the upper instrumented vertebra (UIV) post-surgical shoulder balance. The purpose is to examine the existing UIV selection criteria and correlate with post-surgical shoulder balance in AIS patients. Patients who underwent spinal fusion at age 10-18years for AIS over a 6-year period were reviewed. All patients with a minimum of 1-year radiographic follow-up were included. Imbalance was determined to be radiographic shoulder height |RSH| ≥ 15mm at latest follow-up. Three UIV selection methods were considered: Lenke, Ilharreborde, and Trobisch. A recommended UIV was determined using each method from pre-surgical radiographs. The recommended UIV for each method was compared to the actual UIV instrumented for all three methods; concordance between these levels was defined as "Correct" UIV selection, and discordance was defined as "Incorrect" selection. One hundred seventy-one patients were included with 2.3 ± 1.1year follow-up. For all methods, "Correct" UIV selection resulted in more shoulder imbalance than "Incorrect" UIV selection. Overall shoulder imbalance incidence was improved from 31.0% (53/171) to 15.2% (26/171). New shoulder imbalance incidence for patients with previously level shoulders was 8.8%. We could not identify a set of UIV selection criteria that accurately predicted post-surgical shoulder balance. Further validated measures are needed in this area. The complexity of proximal thoracic curve correction is underscored in a case example, where shoulder imbalance occurred despite "Correct" UIV selection by all methods.

Analysis of posterior pedicle screw-only constructs in surgical treatment of adolescent idiopathic scoliosis with a minimum three-year follow-up

To evaluate clinical outcomes of a group of adolescent idiopathic scoliosis (AIS) patients undergoing posterior pedicle screw-only instrumentations. Between April 2002 and July 2006, 121 AIS patients (93 female and 28 male, average age at operation was 15.5 years which ranged from 10 to 20 years) received posterior pedicle screw-only instrumentation and fusion. All the patients were evaluated by the various-parameters measured in X-ray films before and after surgery, including Cobb angle on coronal plane, Cobb angle on sagittal plane, clavicle angle and shoulder height difference, lowest instrumented vertebrae (LIV) angulation, proximal junction kyphotic angle, the distances of central sacral vertical line (CSVL) to the LIV, to the apical vertebra and to the C(7) plumb line respectively. Complications were followed. An average of (11.0 + or - 1.5) levels was fused. An average coronal correction of proximal thoracic curve was 41.8%, of thoracic curve was 70.8%, of thoracolumbar/lumbar curves was 74.0%. No significant change was found in sagittal alignment. Shoulder balance and apex vertebral to central sacral line were restored well. There were no pseudoarthroses and loss of correction during the follow-ups. One adding-on, 4 proximal thoracic decompensation and 15 proximal junction kyphosis were found during the follow-ups. Posterior pedicle screw-only instrumentation and fusion has excellent radiographic and clinical results with minimal complications in the surgical treatment of AIS.

Spontaneous proximal thoracic correction after anterior selective correction in Lenke type 5 idiopathic scoliosis: the behavior and predictors.

Objective To demonstrate the behavior of spontaneous correction of the proximal tho-racic curve after selective anterior correction in idiopathic scoliosis and analyze its predictors. Methods A total of 29 females with Lenke type 5 idiopathic scoliosis, with an average age of 15.3±2.0 years (range, 12-20) and an average Hisser grade of 3.8±0.8 (range, 0-5), were included. They were treated with anterior se-lective correction, and followed up 24 to 58 months. Results The primary curves were corrected from 47.6°±6.2° preoperatively to 11.9°±7.3° at the final follow-up. The uninstrumented proximal thoracic curves spon-taneously changed from 27.4°±6.7° preoperatively to 16.7°±7.5° at the final follow-up. The correction on pre-operative side-bending X-ray was found to be lower in patients who had more than 2° proximal curve correc-tion loss (F=5.408, P=0.028). There were 3 patients with marked correction loss of proximal curve, among whom two had a preoperative Cobb angle larger than 35°, two bad a flexibility less than 50% and one had a Hisser sign of Grade 0. Correlation analyses revealed that the magnitude of the proximal curve at final follow-up was correlated positively with the preoperative proximal curve magnitude (r=0.664, P< 0.001), the preop-erative side-bending Cobb angle of proximal curve (r=0.555, P=0.001), and the ratio of the proximal curve to the primary curve before surgery (r=0.515, P=-0.002). And the correction rate of the proximal curve was cor-related positively with the correction rate on preoperative side-bending film (r=0.495, P=0.006). Conclusion Growth potential, the curve magnitudes and curve flexibility of proximal thoracic curves before surgery might influence the spontaneous correction of proximal thoracic curves after anterior selective fusion for Lenke type 5 scoliosis, whereas the extent of the spontaneous correction could not be fully predicted according to the curve flexibility. Key words: Scoliosis; Spinal fusion; Internal fixators

Correlation of radiographic, clinical, and patient assessment of shoulder balance following fusion versus nonfusion of the proximal thoracic curve in adolescent idiopathic scoliosis.

Retrospective clinical, radiographic, and patient outcome review of surgically treated adolescent idiopathic scoliosis. To correlate radiographic and clinical features of shoulder balance and the proximal thoracic curve with patient satisfaction outcomes at a minimum 2-year follow-up. Traditionally, radiographic features of a structural proximal thoracic curve have been T1 tilt, proximal thoracic Cobb angle, and proximal thoracic side-bending Cobb; however, these do not always correlate with clinical shoulder balance. A total of 112 patients (single surgeon) with adolescent idiopathic scoliosis and a proximal thoracic curve >or=20 degrees (average 32 degrees, range 20-78 degrees) were evaluated in terms of shoulder balance and curve flexibility/correction. Four groups were analyzed: Group 1, posterior spinal fusion to T2 (proximal thoracic curve included, n = 24); Group 2, posterior spinal fusion to T3 (proximal thoracic curve partially included, n = 23); Group 3, posterior spinal fusion to T4 or T5 (proximal thoracic curve not included, n = 21); and Group 4, anterior spinal fusion to T4 or below (proximal thoracic not included, n = 44). Proximal thoracic, main thoracic, and thoracolumbar-lumbar upright coronal, side-bending, and sagittal Cobb measurements were assessed before surgery, 1 week after surgery, and at a minimum 2-year postoperative follow-up (average 3.8 years, range 2.0-7.6 years). In addition to T1 tilt, clavicle angle (intersection of a horizontal line and the tangential line connecting the highest two points of each clavicle), coracoid height difference, trapezius length (horizontal distance of the T2 pedicle to second rib-clavicle intersection), first rib-clavicle height difference (vertical distance of first rib apex to superior clavicle), and proximal thoracic, main thoracic, and thoracolumbar-lumbar apical vertical translation were determined. Shoulder asymmetry as measured by the radiographic soft tissue shadow was graded as balanced (<1 cm), slight (1-2 cm), moderate (2-3 cm), or significant (>3 cm). A postoperative patient questionnaire addressed shoulder balance and overall appearance at most recent follow-up. The four groups were found to be statistically equivalent in terms of preoperative proximal thoracic curve (P = 0.4146), proximal thoracic side-bending Cobb (P = 0.2199), main thoracic curve (P = 0.6999), and main thoracic side-bending curves (P = 0.7307). Radiographic: Preoperative proximal thoracic measurements correlating with postoperative shoulder balance (P < 0.05) included the clavicle angle (three of four groups with a trend toward statistical significance in the fourth group, P = 0.07) and coracoid height (two of four groups). No other measurement, including T1 tilt and proximal thoracic side-bending Cobb, correlated in more than one group. Proximal thoracic curve correction was greatest in Group 1 (posterior spinal fusion to T2; average 12 degrees) and Group 4 (anterior spinal fusion to T4 or below; average 12 degrees). Clinical: Shoulder balance improved in all four groups (range 0.38-1.00 grades). There was no difference in shoulder balance between groups (P = 0.2723). Patient assessment: All four groups also reported improvement in self-perceived shoulder balance (63% up to one grade, 37% over two-grade improvement), whereas no patient reported worsening of shoulder balance. There was no significant difference in patient outcomes between the four groups (P = 0.3654). The clavicle angle, not T1 tilt, upright proximal thoracic, or side-bending proximal thoracic Cobb, provided the best preoperative radiographic prediction of postoperative shoulder balance. In each of the four groups, postoperative shoulder balance and clinical appearance also improved and correlated with patient postoperative assessments.