Analysis of Preoperative and Operative Factors Influencing Postoperative Shoulder Imbalance in Lenke Type 1 Adolescent Idiopathic Scoliosis

Abstract

Background Postoperative shoulder imbalance is a common complication in adolescent idiopathic scoliosis and may impair patient satisfaction. The little data in the literature on the prediction and treatment of postoperative shoulder imbalance is incongruous. According to some studies, postoperative shoulder imbalance depends on the superior instrumented vertebral bodies, skeletal maturity, extent of correction and flexibility of the major curve.

Question Can preoperative radiological parameters from X-ray and traction films as well as correction of the curves be used to identify a factor impacting on postoperative shoulder imbalance?

Material and Methods Prospective data in adolescent idiopathic scoliosis with thoracic curve (Lenke type 1), operated on between 2015 and 2018 at a scoliosis centre, were analysed retrospectively based on full-length X-rays of the spine (pre-/postOP and follow-up (FU)) and preoperative-traction films: age; correction of proximal, main and lumbar curve; shoulder height [mm]; clavicle angle [°]; T1 tilt [°]; coronal plumb line deviation [mm]. The findings were expressed as means with standard deviation. Changes in parameters over time (postOP-FU) were compared by t test (significance level α = 0.05). The correlation between preOP parameters and extent of correction with postoperative shoulder imbalance (≥ 15 mm) was determined by Pearson correlation and regression classification analysis.

Outcomes 55 patients with adolescent idiopathic scoliosis, mean age of 15 ± 1.4 years. The FU-rate after a mean of 15 months was 80% (n = 44). Correction of proximal, main and lumbar curve: 47.0%, 75.8% and 68.8%, respectively, without statistically significant change (Δ) in FU (p > 0.05). Shoulder height was − 11.0 ± 12.7 mm (preOP), 15.5 ± 13.4 mm (postOP), 10.1 ± 10.6 mm (FU) (p < 0.05). 38% of those with adolescent idiopathic scoliosis had preOP right shoulder elevation; 55% (postOP) and 32% (FU) respectively had postoperative shoulder imbalance (left shoulder elevation). Strong statistical correlation was found for Δshoulder position (FU-preOP) with pre-OP shoulder position (r = − 0.7), and Δshoulder position (pre-OP traction films) (r = 0.5) with pre-OP clavicle angle (r = − 0.5). On regression classification analysis, 81.8% of cases did display postoperative shoulder imbalance if proximal curve correction was ≤ 64.4%; main and lumbar curve correction, Δshoulder elevation (preOP traction films) played a secondary role.

Discussion One common complication even in Lenke type 1 adolescent idiopathic scoliosis is postoperative shoulder imbalance. Preoperative planning should include traction films, preoperative shoulder position and clavicle angle to avoid postoperative shoulder imbalance. Moderate correction of proximal curve is critical for postoperative shoulder balance.

Key words

shoulder elevation - spinal deformity - posterior spinal fusion

Publication History

Article published online:
18 February 2021

• References/Literatur

• 1 Kuklo TR, Lenke LG, Graham EJ. et al. Correlation of radiographic, clinical, and patient assessment of shoulder balance following fusion versus nonfusion of the proximal thoracic curve in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2002; 27: 2013-2020 doi:10.1097/00007632-200209150-00009
• 2 Lenke LG, Betz RR, Harms J. et al. Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am 2001; 83: 1169-1181
• 3 Sielatycki JA, Cerpa M, Beauchamp EC. et al. The Amount of Relative Curve Correction Is More Important Than Upper Instrumented Vertebra Selection for Ensuring Postoperative Shoulder Balance in Lenke Type 1 and Type 2 Adolescent Idiopathic Scoliosis. Spine (Phila Pa 1976) 2019; 44: E1031-E1037 doi:10.1097/BRS.0000000000003088
• 4 Smyrnis PN, Sekouris N, Papadopoulos G. Surgical assessment of the proximal thoracic curve in adolescent idiopathic scoliosis. Eur Spine J 2009; 18: 522-530 doi:10.1007/s00586-009-0902-3
• 5 Trobisch PD, Ducoffe AR, Lonner BS. et al. Choosing fusion levels in adolescent idiopathic scoliosis. J Am Acad Orthop Surg 2013; 21: 519-528 doi:10.5435/JAAOS-21-09-519
• 6 Rose PS, Lenke LG. Classification of operative adolescent idiopathic scoliosis: treatment guidelines. Orthop Clin North Am 2007; 38: 521-529 vi doi:10.1016/j.ocl.2007.06.001
• 7 Lee CS, Hwang CJ, Lee DH. et al. Does fusion to T2 compared with T3/T4 lead to improved shoulder balance in adolescent idiopathic scoliosis with a double thoracic curve?. J Pediatr Orthop B 2019; 28: 32-39 doi:10.1097/BPB.0000000000000520
• 8 Yang H, Im GH, Hu B. et al. Shoulder balance in Lenke type 2 adolescent idiopathic scoliosis: Should we fuse to the second thoracic vertebra?. Clin Neurol Neurosurg 2017; 163: 156-162 doi:10.1016/j.clineuro.2017.10.036
• 9 Chang DG, Kim JH, Kim SS. et al. How to improve shoulder balance in the surgical correction of double thoracic adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2014; 39: E1359-E1367 doi:10.1097/brs.0000000000000578
• 10 Suk S, Kim WJ, Lee CS. et al. Indications of Proximal Thoracic Curve Fusion in Thoracic Adolescent Idiopathic Scoliosis – Recognition and Treatment of Double Thoracic Curve Pattern in Adolescent Idiopathic Scoliosis Treated with Segmental Instrumentation. Spine (Phila Pa 1976) 2000; 25: 2342-2349 doi:10.1097/00007632-200009150-00012
• 11 Cao K, Watanabe K, Hosogane N. et al. Association of postoperative shoulder balance with adding-on in Lenke Type II adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2014; 39: E705-E712 doi:10.1097/brs.0000000000000325
• 12 Kuklo TR, Lenke LG, Won DS. et al. Spontaneous proximal thoracic curve correction after isolated fusion of the main thoracic curve in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2001; 26: 1966-1975 doi:10.1097/00007632-200109150-00006
• 13 Winter RB, Denis F. The King V curve pattern. Its analysis and surgical treatment. Orthop Clin North Am 1994; 25: 353-362
• 14 Schwab F, Blondel B, Chay E. et al. The comprehensive anatomical spinal osteotomy classification. Neurosurgery 2014; 74: 112-120 discussion 120 doi:10.1227/NEU.0000000000000182o
• 15 Jian YM, Yang SH, Hu MH. Assessment of Change of Shoulder Balance in Patients with Adolescent Idiopathic Scoliosis after Correctional Surgery. Orthop Surg 2018; 10: 198-204 doi:10.1111/os.12399
• 16 Lee CS, Hwang CJ, Lim EJ. et al. A retrospective study to reveal factors associated with postoperative shoulder imbalance in patients with adolescent idiopathic scoliosis with double thoracic curve. J Neurosurg Pediatr 2016; 25: 744-752 doi:10.3171/2016.6.PEDS16162
• 17 Smith PL, Donaldson S, Hedden D. et al. Parentsʼ and patientsʼ perceptions of postoperative appearance in adolescent idiopathic scoliosis. Spine (Phila Pa 1976) 2006; 31: 2367-2374 doi:10.1097/01.brs.0000240204.98960.dd