Abstract
BackgroundCurrent surgical treatment options for early onset scoliosis (EOS), with distraction- or growth-guidance implants, show limited growth and high complication rates during follow-up. We developed a novel implant concept, which uses compressed helical springs positioned around the rods of a growth-guidance construct. This spring distraction system (SDS) provides continuous corrective force to stimulate spinal growth, can be easily contoured, and can be used with all standard spinal instrumentation systems. PurposeTo assess curve correction and -maintenance, spinal growth, complication rate, and health-related quality of life following SDS treatment. Study DesignProspective cohort study. Patient sampleAll skeletally immature EOS patients with an indication for growth-friendly surgery and without bone- or soft tissue weakness were eligible to receive SDS. For this study, all included patients with at least 2-year follow-up were analyzed. Outcome measuresCoronal Cobb angle, sagittal parameters, T1-T12, T1-S1, and instrumented (ie, bridged segment) spinal height and freehand length, complications and re-operations, and the 24-Item Early Onset Scoliosis Questionnaires (EOSQ-24) score. MethodsAll primary- and conversion patients (conversion from failed other systems) with SDS and ≥2 years follow-up were included. Radiographic parameters were compared preoperatively, postoperatively and at latest follow-up. Spinal length increase was expressed as mm/year. ResultsTwenty-four skeletally immature EOS patients (18 primary and 6 conversion cases) were included. There were five idiopathic, seven congenital, three syndromic, and nine neuromuscular EOS patients. Mean age at implantation was 9.1 years (primary: 8.4; conversion: 11.2). Major curve improved from 60.3° to 35.3°, and was maintained at 40.6° at latest follow-up. Mean spring length increase during follow-up was 10.4 mm/year. T1-S1 height increased 9.9mm/year and the instrumented segment height showed a mean increase of 0.7 mm/segment/year. EOSQ-24 scores dropped after surgery from 75.6 to 67.4 but recovered to 75.0 at latest follow-up. In total, 17 reoperations were performed. Ten reoperations were performed to treat 9 implant-related complications. In addition, 7 patients showed spinal growth that exceeded expected growth velocity; their springs were retensioned during a small reoperation. ConclusionThe 2-year follow-up results from this prospective cohort study indicate that the concept of spring distraction may be feasible as an alternative to current growing spine solutions. Curve correction and growth could be maintained satisfactory without the need for repetitive lengthening procedures. However, as in all growth-friendly implants, complications and reoperations could not be prevented, which emphasizes the need for further improvement.
Highlights
Onset scoliosis (EOS), if left untreated, can cause severe cardiopulmonary dysfunction [1−3]
Current distraction-based implants are lengthened intermittently, either with repeated surgical procedures or with a magnetic actuator [4,5]. While these systems are widely used for the surgical treatment of early onset scoliosis (EOS), they are not without disadvantages
We developed the Spring Distraction System (SDS), which employs the continuous distraction force of a compressed helical coil spring that is positioned around a standard rod that is allowed to slide at the proximal- or distal foundation (Fig. 1) [36]
Summary
Onset scoliosis (EOS), if left untreated, can cause severe cardiopulmonary dysfunction [1−3]. Current distraction-based implants are lengthened intermittently, either with repeated surgical procedures (traditional growing rod; TGR) or with a magnetic actuator (magnetically controlled growing rod; MCGR) [4,5] While these systems are widely used for the surgical treatment of EOS, they are not without disadvantages. Current surgical treatment options for early onset scoliosis (EOS), with distraction- or growth-guidance implants, show limited growth and high complication rates during follow-up. We developed a novel implant concept, which uses compressed helical springs positioned around the rods of a growth-guidance construct This spring distraction system (SDS) provides continuous corrective force to stimulate spinal growth, can be contoured, and can be used with all standard spinal instrumentation systems.
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