Anterior vertebral body tethering for idiopathic scoliosis in growing children: A systematic review

Differential vertebral body growth is maintained after vertebral body tethering surgery for idiopathic scoliosis: 4-year follow-up on 888 peri-apical vertebrae and 592 intervertebral discs

PURPOSE

To radiographically evaluate if vertebral body tethering (VBT) can maintain differential peri-apical vertebral growth at medium-term follow-up of 4 years.

METHODS

A prospective, international, multicenter database was queried to identify idiopathic scoliosis patients treated with thoracic VBT. Concave vs. convex vertebral body height, vertebral wedging, and disc wedging of the 3 peri-apical vertebrae were measured by two independent observers at 5 timepoints (pre-operative to 4-year follow-up).

RESULTS

65 skeletally immature patients (60 female, mean 12.8 years old, 21 with open triradiate cartilages) met inclusion criteria. Mean pre-operative maximum scoliosis of 50 ± 8° decreased significantly post-operatively to 27 ± 9° (p < 0.001), which remained stable at 4-year follow-up 30 ± 17° (p = 0.38 vs. post-operative). Mean instrumented scoliosis was 21 ± 14° at 4-year follow-up, which was significantly different than 4-year maximum scoliosis (p < 0.001). Mean pre-operative kyphosis of 30 ± 12° did not significantly change post-operatively (p = 1.0) and remained stable at 4-year follow-up (35 ± 18°; p = 0.05). Mean individual convex vertebral height increased from 17.7 ± 1.9 mm to 19.8 ± 1.5 mm (p < 0.001), while mean individual concave height increased from 14.8 ± 1.9 mm to 17.6 ± 1.6 mm (p < 0.001). Summing the peri-apical heights, the difference in height from pre-operative to 4-year follow-up was greater on the concave (8.3 ± 4.7 mm) than on the convex side (6.2 ± 4.7 mm) (p < 0.001). Mean individual vertebral wedging decreased from 6 ± 2° at pre-operative to 4 ± 2° at 4-year follow-up (p < 0.001). Mean total vertebral and disc wedging started at 29 ± 7° pre-operatively, decreased to 16 ± 6° at post-operative (p < 0.001), then further decreased to 14 ± 8° at 4-year follow-up (p < 0.001). Patients with open triradiate cartilages at the time of surgery had a larger height change over the 4 years compared to those with closed triradiate cartilages (p < 0.001).

CONCLUSION

Patients with idiopathic scoliosis treated with VBT demonstrated differential vertebral growth which was maintained at minimum 4-year follow-up. This effect was more pronounced in patients whose triradiate cartilages were open at the time of surgery.

LEVEL OF EVIDENCE

III.

Gender-Related Factors Influence the Subjective Perception of Deformity in Patients Undergoing Surgery for Idiopathic Scoliosis

The present study aims to depict the importance of gender-related factors in the subjective perception of spine deformity in adolescents undergoing posterior instrumented fusion for scoliosis. Patients undergoing posterior spinal instrumentation and fusion (PSF) for idiopathic adolescent scoliosis (AIS) were recruited. The following data were recorded: gender, age, parents' civil status, Tegner Activity Scale (TAS), body mass index (BMI), concomitant diseases, and history of neuropsychological disorders. Each patient underwent clinical and radiological evaluations according to the protocol used at our institution. All the patients were assessed before surgery using the following Patient-Reported Outcome Measures (PROMs): the Italian version of the revised Scoliosis Research Society-22 patient questionnaire (SRS-22R), the Quality-of-Life Profile for Spinal Deformities (QLPSDs) questionnaire, and the Spinal Appearance Questionnaire (SAQ). The present study recruited 80 patients (male: 19, female: 61). A significant correlation was observed between BMI, TAS, and subjective perception scores. A worse deformity perception was observed in female patients and patients with divorced parents. Gender-related factors impact the subjective perception of spine deformity in patients undergoing PSF for AIS. Specific assessment and correction are needed to improve postoperative outcomes in these patients.

Vertebral body tethering for idiopathic scoliosis: a systematic review and meta-analysis

PURPOSE

Vertebral body tethering (VBT) is a recent procedure to correct and reduce spinal curves in skeletally immature patients with adolescent idiopathic scoliosis (AIS). The purpose of this systematic review and meta-analysis is to determine the expected curve reduction and potential complications for adolescent patients after VBT.

METHODS

PubMed, Embase, Google Scholar and Cochrane databases were searched until February 2022. Records were screened against pre-defined inclusion and exclusion criteria. Data sources were prospective and retrospective studies. Demographics, mean differences in Cobb angle, surgical details and complication rates were recorded. Meta-analysis was conducted using a random-effects model.

RESULTS

This systematic review includes 19 studies, and the meta-analysis includes 16 of these. VBT displayed a statistically significant reduction in Cobb angle from pre-operative to final (minimum 2 years) measurements. The initial mean Cobb angle was 47.8° (CI 95% 42.9-52.7°) and decreased to 22.2° (CI 95% 19.9-24.5°). The mean difference is - 25.8° (CI 95% - 28.9-22.7) (p < 0.01). The overall complication rate was 23% (CI 95% 14.4-31.6%), the most common complication was tether breakage 21.9% (CI 95% 10.6-33.1%). The spinal fusion rate was 7.2% (CI 95% 2.3-12.1%).

CONCLUSION

VBT results in a significant reduction of AIS at 2 years of follow-up. Overall complication rate was relatively high although the consequences of the complications are unknown. Further research is required to explore the reasons behind the complication rate and determine the optimal timing for the procedure. VBT remains a promising new procedure that is effective at reducing scoliotic curves and preventing spinal fusion in the majority of patients.

LEVEL OF EVIDENCE

Systematic review of Therapeutic Studies with evidence level II-IV.

The different applications of Vertebral Body Tethering - Narrative review and clinical experience

Background

Vertebral body tethering (VBT) has been originally developed as a growth modulation technique for the surgical management of skeletally immature patients with adolescent idiopathic scoliosis (AIS). Given the positive results obtained in this setting, the use of VBT is gradually expanding to other patient categories, such as those with no or limited remaining growth or with non-idiopathic scoliosis. Aim of this manuscript is to offer an overview over the current applications of VBT, along with imaging and comments derived from the clinical experience. The work was based on a literature search conducted in January 2023 on Pubmed, Scopus and Web of Science databases. Following keywords were used for the search: vertebral body tethering, adolescent idiopathic scoliosis, early onset scoliosis, neuromuscular scoliosis, syndromic scoliosis.

Results

Three patient categories in which VBT has been applied have been highlighted: VBT for growth modulation in AIS, VBT as anterior scoliosis correction in AIS and VBT for non-idiopathic curves or early-onset scoliosis.

Conclusion

While growth modulation in AIS still represents the most widespread use of VBT, the use of this technique has yielded positive results in different settings as well, such as scoliosis correction in AIS or temporary or definitive curve management in non-AIS curves. While long-term results are lacking, patient selection seems to play a central role to reduce the complication rate and ensure predictable and stable results.

Vertebral body tethering: An alternative to posterior spinal fusion in idiopathic scoliosis?

Introduction

Skeletally immature patient with adolescent idiopathic scoliosis (AIS) whose curves continue to progress despite bracing should be treated surgically. Vertebral body tethering (VBT) is a non-fusion, compression-based, growth preserving alternative to posterior spinal fusion (PSF) based on the concept of 'growth modulation' to prevent possible functional complications secondary to fusion while correcting scoliotic deformity. This review aims to shed light on the indications of VBT, short- and medium-term outcomes, describe the surgical technique and associated complications, and to compare its efficacy to that of PSF.

Methods

A review of peer-reviewed literature on VBT as a surgical technique, its indications, outcomes, complications, and comparison with other surgical interventions to correct AIS was conducted in December 2022.

Results

Indications remain controversial and mainly include stage of skeletal maturity based on radiographic markers, curve location, magnitude and flexibility, and presence of secondary curve. Assessment of VBT clinical success should not be restricted to improvement in radiographic parameters but should include functional results and patient-centered outcomes, improved body image and pain, and durability of outcomes. In contrast to fusion, VBT seems to be associated with preserved spinal growth, shorter recovery, potentially better functional outcomes, less motion loss but possibly less curve correction.

Discussion

Yet still, with VBT there exists a risk of overcorrection, construct breakage or failure of procedure which require revision and at times conversion to PSF. Patient and family preferences must be accounted for acknowledging gaps in knowledge, attributes and drawbacks of each intervention.