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Curve Behavior of Distal Segments After Posterior-Only Hemivertebra Resection for Congenital Cervicothoracic
Yang Li1, Zezhang Zhu1, Wanyou Liu1
1Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
Insights
Distal compensatory curves in congenital cervicothoracic hemivertebra (CTH) scoliosis may slightly progress after posterior hemivertebra resection. Emerging scoliosis was observed in 19.6% of patients, necessitating close follow-up.
Area of Science:
- Spine surgery
- Pediatric orthopedics
- Scoliosis research
Background:
- Congenital cervicothoracic hemivertebra (CTH) scoliosis often requires surgical correction.
- Posterior hemivertebra resection effectively corrects spinal alignment but can lead to distal curve progression.
- The behavior and mechanisms of distal non-structural compensatory curves post-surgery remain unclear.
Purpose of the Study:
- To analyze the curve evolution of distal non-structural compensatory curves after posterior-only hemivertebra resection in CTH patients.
- To investigate the potential mechanisms driving these curve changes.
- To describe the characteristics of emerging scoliosis (ES) in this patient cohort.
Main Methods:
- Retrospective consecutive study of CTH patients undergoing posterior-only hemivertebra resection.
- Minimum 24-month follow-up with coronal plane parameter measurements (local scoliosis, clavicle angle, head shift, distal Cobb angle).
- Definition of emerging scoliosis (ES) as >20° progression in distal curves at least 2 levels from the lower instrumented vertebra.
Main Results:
- 51 CTH patients (mean age 8.5 years) showed significant correction of local scoliosis and clavicle angle (p<0.05).
- Distal compensatory curves slightly increased from 6.5° post-surgery to 11.6° at latest follow-up (p=0.002), correlating with clavicle angle changes (r=0.49, p=0.038).
- Emerging scoliosis (ES) occurred in 19.6% of patients, with compensatory ES appearing within 6 months and idiopathic ES later, potentially linked to growth. No revision surgeries were needed.
Conclusions:
- Distal compensatory curves in CTH patients tend to show slight progression post-posterior hemivertebra resection.
- Emerging scoliosis (ES) has a prevalence of 19.6%, with distinct compensatory and idiopathic curve behaviors identified.
- Longitudinal follow-up is crucial for CTH patients treated with posterior hemivertebra resection.
Study Design:
A retrospective and consecutive study.
Objective:
To demonstrate the curve evolution of distal non-structural compensatory curves in patients with congenital cervicothoracic hemivertebra (CTH) scoliosis undergoing posterior-only hemivertebra resection and to propose the possible mechanisms of this specific phenomenon.
Summary Of Background Data:
Though the spinal alignment could be well corrected via posterior hemivertebra resection in CTH patients, the high prevalence of distal curve progression was remarkable. However, the curve behavior of distal non-structural compensatory curves and its possible mechanisms were unclear.
Methods:
This study retrospectively reviewed a consecutive series of CTH patients undergoing posterior-only hemivertebra resection with a minimum 24 months follow-up. The parameters measured in coronal plane included local scoliosis, clavicle angle, head shift, and the Cobb angle of distal unfused segments. The distal curve was considered as an emerging scoliosis (ES) if with more than 20° progression and the apex of distal curve no less than 2 levels away from the lower instrumented vertebra.
Results:
A total of 51 CTH patients with a mean age of 8.5 ± 3.8 years at surgery and a mean 38.0 ± 5.3 months follow-up were recruited. The correction of local scoliosis and clavicle angle was statistically significant (p < 0.05 for all). The distal compensatory curve was 11.8 ± 5.3° before surgery and 6.5° ± 4.1° after surgery (p < 0.001), which was slightly increased to 11.6° ± 10.9° (p = 0.002) at the latest follow-up. During follow-up, the increase of distal compensatory curve was significantly correlated with the change in clavicle angle (r = 0.49, p = 0.038). The ES was observed in 10 patients (19.6%) with an average value of 28.0 ± 2.1° at diagnosis, including 7 patients within 6 months and 3 patients after 5 years postoperatively. The mean value of ES was 31.9° ± 3.1° at the latest follow-up, while no patients required revision surgery. The ES was classified into compensatory and idiopathic types according to the typical curve behaviors. The compensatory ES usually presented within 6 months after operation and was responsible for further reconstruction of head and shoulder balance. While the idiopathic ES occurred at adolescent which may be related to the rapid body growth.
Conclusions:
Distal compensatory curve had a tendency toward slight progression during follow-up in CTH patients with posterior hemivertebra resection surgery. The prevalence of emerging scoliosis was 19.6% and the typical compensatory and idiopathic curve behavior were firstly proposed. Close and longitudinal follow-up was thus highly recommended for CTH patients with posterior HV resection surgery.
