Magnetically Controlled Growing Rods Graduation: Deformity Control with High Complication Rate.

STUDY DESIGN

A multicenter retrospective review of consecutive series of patients.

OBJECTIVE

Long-term experience with using the magnetically controlled growing rods (MCGR) to treat patients with deformity in the growing spine to the conclusion of treatment with posterior spine fusion.

SUMMARY OF BACKGROUND DATA

MCGR treatment for growing spine gained popularity with paucity of long-term follow up data. We hypothesized that final fusion might be more effective in bringing additional correction of the spine deformity after treatment with MCGR than that reported after traditional growing rods (TGR) due to less scarring and auto-fusion.

METHODS

Retrospective review of 47 patients with varied etiology, treated between 2011 and 2017 which graduated treatment were followed in five academic medical centers for average of 50 months (range, 10-88).

RESULTS

The initial mean coronal deformity of 69.6° (95% CI 65-74) was corrected to 40° (95% CI 36-40) immediately after the MCGR implantation but progressed to 52.8° (95% CI 46-59) prior to the final surgery (P < 0.01). Nevertheless, thoracic spine growth (T1-T12 height) improved from 187.3 mm (95% CI 179-195) following index surgery to 208.9 mm (95% CI 199-218) prior to final fusion (P < 0.01). Significant correction and spinal length were obtained at final fusion, but metallosis was a frequent observation (47%, 22/47). The average growth rate was 0.5 mm/month (95% CI 0.3-0.6). The overall complication rate within our cohort was 66% (31/47) with 45% (21/47) of unplanned returns to the operating theater. 32% (15/47) of the patients had an implant related complication. Unplanned surgery was highly correlated with thoracic kyphosis greater than 40° (OR 5.42 95% CI 1.3-23).

CONCLUSION

Treatment of growing spine deformities with MCGR provides adequate control of spine deformity it is comparable to previously published data about TGR. The overall high complications rate over time and specifically implant related complications.Level of Evidence: 4.