Asian Spine J.  2019 Oct;13(5):793-800. 10.31616/asj.2018.0206.

Hooks at the Upper Instrumented Vertebra Can Adjust Postoperative Shoulder Balance in Patients with Adolescent Idiopathic Scoliosis: 5 Years or More of Follow-up

• Kuroya S
• Akazawa T
• Kotani T
• Sakuma T
• Minami S
• Torii Y
• Umehara T
• Iinuma M
• Murakami K
• Orita S
• Inage K
• Eguchi Y
• Fujimoto K
• Shiga Y
• Nakamura J
• Inoue G
• Miyagi M
• Saito W
• Ohtori S
• Niki H

• KMID: 2462009
• DOI: http://doi.org/10.31616/asj.2018.0206

Abstract

STUDY DESIGN: A retrospective cohort study. PURPOSE: This study aims to investigate postoperative shoulder imbalance (PSI) ≥5 years postoperatively in patients who underwent posterior spinal fusion using hooks at the upper instrumented vertebra (UIV) for Lenke type 1 adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: Studies have reported PSI due to excessive correction of the main thoracic curve.
METHODS
We examined 56 patients with AIS who underwent a posterior spinal fusion with hooks at the UIV from 2004 to 2010. Of these, we enrolled 14 patients who underwent surgery, at least, 5 years ago. X-rays and Scoliosis Research Society-22 (SRS-22) questionnaire were administered. To evaluate the shoulder balance, T1 vertebral tilt angle (T1 tilt), clavicle angle, and radiographic shoulder height (RSH) were measured. PSI was considered as the absolute value of the postoperative RSH being ≥20 mm. Based on radiographs obtained immediately postoperatively, we divided patients into two groups as follows: the balanced group (absolute value of RSH <20 mm) and imbalanced group (absolute value of RSH ≥20 mm).
RESULTS
The frequency of PSI was 28.6% immediately postoperatively, 0% 2 years postoperatively, and 7.1% at the last follow-up. In the balanced group, PSI did not occur even at 2 years postoperatively or at the last follow-up. In the imbalanced group, PSI was improved in all patients 2 years postoperatively and all patients, except one patient, at the last follow-up. No significant differences were noted in the frequency of distal adding-on at 2 years postoperatively or the last follow-up between the balanced group and the imbalanced group. We observed moderate negative correlations between the absolute value of T1 tilt and the SRS-22 pain and satisfaction at the last follow-up.
CONCLUSIONS
Hooks at the UIV could adjust the shoulder balance to avoid long-term PSI in patients with AIS.

Keyword

Adolescent idiopathic scoliosis; Long-term follow-up; Postoperative shoulder imbalance; Shoulder balance; Hook of the upper instrumented vertebra

MeSH Terms

Adolescent*
Clavicle
Cohort Studies
Follow-Up Studies*
Humans
Retrospective Studies
Scoliosis*
Shoulder*
Spinal Fusion
Spine*