Convex Instrumented Hemiepiphysiodesis With Concave Distraction: A Treatment Option for Long Sweeping Congenital Curves

Comparison of the efficacy of the convex side short fusion combined with concave side single growing rod technique and the traditional bilateral growing rod technique in the treatment of early onset scoliosis

OBJECTIVES

The application of a growing rod technique can retain the growth and development potential of the spine and thorax while controlling the progression of scoliosis deformity. Theoretically, convex side short fusion combined with a concave side single growing rod technique can significantly reduce the asymmetric growth of the spine in the vertex region in most patients. However, the final clinical outcome of various techniques is yet to be clearly determined and compared between studies. Therefore, we compared the efficacy of these two growing rod techniques in treating early onset scoliosis.

METHODS

In a retrospective study of 152 EOS patients seen between 2013.1 and 2019.12, 36 cases of EOS patients were selected for inclusion. Among the 36 cases, 11 cases were treated with convex side short fusion combined with a concave side single growing rod technique, group (A) The remaining 25 cases were treated with traditional bilateral growing rod technique, group (B) Age, gender, etiology, follow-up time, Cobb angle of main curve, T1-S1 height, coronal trunk shift, sagittal vertical axis (SVA), Cobb angle of thoracic kyphosis at last follow-up, and Cobb angle at proximal junction kyphosis of the first and last post-operation follow-up were recorded. In addition, internal fixation related complications, infection, nervous system complications were recorded as well.

RESULTS

There was no statistically significant difference between group A and group B in preoperative age, Cobb angle of main curve, coronal trunk shift, T1-S1 height, SVA, Cobb angle of thoracic kyphosis (p > 0.05). However, at the last follow-up (Group A, mean 4.4 ± 1.01 years; Group B, mean 3.6 ± 0.01 years) the Cobb angle of the main curve was less and T1-S1 height greater in group A compared with group B (p < 0.05). There was no statistically significant difference between group A and group B in the correction rate of the Cobb angle of the main curve or the growth rate of T1-S1 height (p > 0.05). There was no statistically significant difference in the coronal imbalance ratio, thoracic kyphosis abnormality ratio, or the occurrence PJK ratio between group A and group B at the last follow-up (p > 0.05), but the sagittal imbalance ratio and internal fixation abnormality ratio were higher in group A than in the group B (p < 0.05).

CONCLUSIONS

During the treatment of EOS, both the convex side short fusion combined with concave side single growing rod technique and traditional bilateral growing rod technique can correct the Cobb angle of main curve with no significant hindering of the spinal growth observed. The traditional bilateral growing rod technique has advantages in control of the sagittal balance of the spine, and the complications associated with internal fixation were lower.

Dual Growing Rods and the Apical Control Technique for Treating Congenital Early-Onset Scoliosis: Lessons Learned

BACKGROUND

Congenital early-onset scoliosis (CEOS) is characterized by a spectrum of vertebral anomalies, including formation failures and segmentation failures at the apex segment, which makes CEOS different from other etiologies of early-onset scoliosis. To date, studies on patients who have graduated from CEOS treatment using traditional dual growing rods (TDGR) have been scarce, and the preliminary results of TDGR with or without the apical control technique (ACT) have varied. We therefore compared the final outcomes of patients with CEOS who graduated from TDGR with or without the ACT.

METHODS

A retrospective study of patients with CEOS who had graduated from TDGR treatment performed from 2007 to 2020 was conducted. Graduation included final fusion or observation after reaching skeletal maturity. Patients were divided into the ACT-TDGR group (apical vertebrectomy and/or hemivertebrectomy with short fusion and TDGR) and the TDGR-only group. Demographic characteristics, radiographic data, patient-reported clinical outcomes, pulmonary function, and complications were analyzed.

RESULTS

A total of 41 patients with CEOS were enrolled: 13 in the ACT-TDGR group and 28 in the TDGR-only group. The lengthening intervals were longer in the ACT-TDGR group (mean [and standard deviation], 1.26 ± 0.66 years) than in the TDGR-only group (0.80 ± 0.27 years). The preoperative main curve was larger in the ACT-TDGR group (80.53° ± 19.50°) than in the TDGR-only group (64.11° ± 17.50°). The residual curve was comparable between groups (26.31° ± 12.82° in the ACT-TDGR group compared with 27.76° ± 15.0° in the TDGR group) at the latest follow-up. The changes in apical vertebral rotation and thoracic rotation were significantly larger in the ACT-TDGR group. Patients had comparable T1-12 and T1-S1 heights, pulmonary function, and 22-item Scoliosis Research Society (SRS-22) scores at the latest follow-up. The mean number of mechanical-related complications per patient was lower in the ACT-TDGR group (0.77 ± 0.73) than in the TDGR-only group (1.54 ± 1.43). Seventeen patients underwent final fusion.

CONCLUSIONS

In this small-scale study, we observed that both ACT-TDGR and TDGR-only could correct the deformity while allowing for spinal growth in patients with CEOS. ACT-TDGR yielded better correction in severe cases and did not have a deleterious effect on spinal height. A large number of cases will be needed to validate the clinical value of the ACT.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Hybrid technique versus traditional dual growing rod technique to treat congenital early-onset scoliosis: a comparative study with more than 3 years of follow-up

OBJECTIVE

The authors' objective was to compare the intermediate outcomes of patients with severe congenital early-onset scoliosis (CEOS) treated with posterior vertebrectomy/hemivertebrectomy with short fusion and dual growing rods (hybrid technique [HT]) and those treated with traditional dual growing rods (TDGRs).

METHODS

A retrospective study of patients who underwent the HT and TDGR technique for CEOS was conducted. The inclusion criteria were CEOS (age < 10 years), Risser stage 0, treatment with HT or TDGR, index surgery performed between 2004 and 2017, and minimum follow-up of 3 years. For patients who completed lengthening procedures, the last lengthening procedure was considered the latest follow-up. Demographic, radiographic, clinical, and patient-reported outcomes and revisions were compared between groups.

RESULTS

Sixty-one patients with CEOS were included in this study, with 16 treated with HT and 45 with TDGR technique. There were no differences in age at index surgery, duration of treatment, or number of lengthening procedures. The lengthening interval was longer in the HT group. The preoperative mean ± SD main curve was 81.8° ± 17.1° for the HT group and 63.3° ± 16.9° for the TDGR group (p < 0.05). However, main curve correction was better in the HT group, and no differences in residual curve were found between groups. Although the preoperative apex vertebral translation (AVT) of the HT group was greater, the correction of AVT was better in the HT group (p < 0.05). No differences in T1-S1 and T1-12 height were found between groups at the latest follow-up. The growth of T1-S1 height was less in the HT group (p < 0.05), whereas the growth of T1-12 height was similar between groups. Patients in the HT group had a lower risk of mechanical complications but higher risks of dural tears and neurological complications.

CONCLUSIONS

HT may provide better correction and apex control ability than TDGR for EOS patients with severe and rigid deformity at the apex level, and it significantly decreased the risk of mechanical complications with little influence on growth of the thoracic spine. HT may be an option for patients with severe CEOS with large asymmetrical growth potential around the apex of the curve.

The Effect of Apical Vertebra Position on Growing Rod Treatment: A Clinical and Finite Element Study

BACKGROUND

Growing rods (GRs) is a commonly utilized technique for the management of early-onset scoliosis. The significance of the position of the apical vertebrae relative to the rods is not known. The purpose of this study is to analyze the potential effects of the position of the apical vertebrae in relation to the GRs on deformity control through plain radiographs and finite element analysis (FEA) modeling.

METHODS

We identified 140 patients treated with GR between 2000 and 2018. Patients who had a congenital vertebral anomaly or <2-year follow-up were excluded. Curve magnitude, traction radiograph under general anesthesia (TRUGA) flexibility, apical rotation, the lengths of T1-12, T1-S1, and the instrumented segments were recorded. Patients were divided into 3 groups according to the apical position on the postoperative radiographs: group 1 (both pedicles are between the rods), group 2 (convex rod is between the apical vertebra pedicles), group 3 (both pedicles are lateral to the convex rod). FEA models were created simulating the 3 groups. Both radiographic and FEA data were analyzed to compare the deformity control and growth in each group.

RESULTS

Fifty-eight patients were included in the final analyses (mean age 84 mo; range: 38 to 148). Ten patients (17%) were in group 1, 34 (59%) in group 2, and 14 (24%) in group 3. Difference between TRUGA flexibilities was statistically insignificant. Group 3 was the least successful in terms of both height gain and rotational control. FEA showed a decrease in rotation and displacement for every group, however, the residual rotation and displacement was highest in group 3.

CONCLUSIONS

Bringing the apex in line with the GR increases the capacity of growth preservation as it results in largest height gain and better deformity control. FEA model demonstrated that distraction alone is inadequate for controlling rotation, and with increasing apical translation, residual rotation after distraction also increases.

LEVEL OF EVIDENCE

Level III.

Hybrid Growing Rod Technique of Osteotomy With Short Fusion and Spinal Distraction: An Alternative Solution for Long-Spanned Congenital Scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVE

The current study aimed to evaluate the effectiveness of the hybrid growing rod (GR) technique for the treatment of young children with congenital scoliosis (CS).

SUMMARY OF BACKGROUND DATA

Congenital vertebral anomalies within long-spanned kyphoscoliosis were difficult to be managed by either definitive spinal fusion or standard GR technique. Hybrid technique of one-stage posterior osteotomy with short fusion and GR distraction was proposed in previous studies. There is, however, paucity of data regarding its effectiveness.

METHODS

Thirteen patients (mean age, 5.4 ± 2.0 yr) who had undergone hybrid GR treatment were retrospectively reviewed, including 8 patients treated with single GR and 5 patients with dual GR. All of their radiographic data were measured, and surgical complications were recorded.

RESULTS

On average, the current cohort had 4.1 ± 1.7 lengthening procedures. After the index surgery, the major curve improved remarkably from 86.4° ± 11.9° to 37.3° ± 12.4° (P < 0.001). The global kyphosis significantly decreased from 66.8° ± 16.1° to 33.3° ± 3.5° postoperatively. Both value remained steady during follow-up. There were no significant difference between single GR and dual GR groups in terms of the coronal deformity correction, whereas correction loss of global kyphosis in single GR group was significantly higher than that in dual GR group (P = 0.039). After the index surgery, T1-S1 height averagely gained 4.4 ± 0.8 cm and it grew at an average rate of 1.31 ± 0.24 cm/yr during the follow-up. Two complications were identified in two patients, including one with rod fracture and one with proximal junctional kyphosis.

CONCLUSION

The hybrid GR technique was effective in correcting spinal deformity and allowing continuous spinal growth. The optimal indications were young children with apical vertebrae anomalies and a long-spanned kyphoscoliosis.

LEVEL OF EVIDENCE

3.

Is Magnetically Controlled Growing Rod the Game Changer in Early-onset Scoliosis? A Preliminary Report

BACKGROUND

Magnetically controlled growing rod (MCGR) concept was introduced with the premise of minimizing the repetitive lengthening surgeries, which is default in traditional growing rod (TGR) treatment for early-onset scoliosis (EOS). Despite good radiographic outcomes, previous studies did not compare identical patient groups in terms of etiology and deformity characteristics; therefore, a true comparison of the MCGR and TGR is essential. This study was designed to compare 2 techniques in terms of clinical, radiologic, and health-related quality of life (HRQoL) outcomes.

METHODS

Patients with long sweeping congenital curves who underwent convex growth arrest and concave distraction (with TGR or MCGR) were retrospectively reviewed. Instrumented all-posterior convex growth arrest and concave distraction with growing rod technique were performed. Demographic parameters, follow-up time, number of lengthening procedures, radiographic parameters, number of unplanned surgeries, and complications were recorded. The Early-Onset Scoliosis Questionnaire (EOSQ-24) was used to evaluate HRQoL outcomes.

RESULTS

A total of 20 patients were included (10 MCGR, 10 TGR). No significant differences were found with regard to average age, follow-up time, radiographic parameters, or complications. Overall surgery per patient including index surgery, and planned and unplanned procedures were significantly lower in the MCGR group (8.8 vs. 1.3) (P=0.01). No patient in either group had graduated from growing rod treatment. HRQoL analysis revealed no significant difference between the 2 groups in any specific domain or in the overall score of the EOSQ-24.

CONCLUSIONS

Although equally effective in controlling the deformity and superior in reducing the number of surgeries with comparable complication rates, MCGR does not offer any significant improvement in HRQoL outcomes or the overall complication rate. Despite the obvious advantages, according to this preliminary report, the current technology and technique of MCGR may not be sufficient to be the long-awaited "game changer" in the treatment of EOS.