Limited-efficacy Testing of SDS and NEMOST for Early Onset Neuromuscular Scoliosis

Limited-efficacy Testing of Spring Distraction System (SDS) and a Bilateral One Way Rod (NEMOST) for Early Onset Neuromuscular Scoliosis (BiPOWR)

The primary aim of this study is to investigate and describe the limited efficacy of the Spring Distraction System (SDS) and Bilateral One Way Rod (NEMOST) in maintaining curve reduction without repeat lengthening procedures and complications.

Secondary aims are to describe growth of the instrumented spine, health-related quality of life, and to compare both devices.

Several innovative solutions have been developed to treat growing children with a severe scoliosis. One device (SDS) was developed internally at the department of orthopaedics UMC Utrecht in the Netherlands. The other device (NEMOST) was developed at the Necker Hospital in France.

This study is designed as a multicenter, limited-efficacy study using two prospective cohorts according a randomised clinical trial. The study will be performed in two centers (UMC Utrecht, Amsterdam UMC and Erasmus MC).

Primary endpoints are the limited-efficacy in terms of maintenance of curve correction and occurrence of SAEs related to the procedure. These data will be compared to a recently described cohort of patients that received a "standard treatment", the MGCR (Skov et al., 2017). Secondary endpoints include spinal- and implant growth, patient performance based on the EOSQ 24 questionnaire and surgical parameters.

Inclusion Criteria:

• Non ambulant
• Neuromuscular or syndromal scoliosis
• Progressive scoliosis indicated for bipolar fixation extending to the pelvis
• Diagnosis of scoliosis before age 10
• Patient under 12 and open triradiate cartilage (usually closes around 12 years for girls and 14 years for boys)
• Main curve proximal end vertebra below Th 3
• Non rigid curve
• Patients who have an indication for a primary surgery

Exclusion Criteria:

• Ambulant
• Patients with closed triradiate cartilage
• Patients with a skeletal dysplasia that effects growth (Achondroplasia, SED)
• Patients with a systemic disease which severely influences bone quality e.g. osteogenesis imperfecta, metabolic diseases
• Patients with soft tissue weakness (Ehler Danlos, Marfan, Neurofibromatosis, Prader Willi)
• Patients that have a congenital anomaly of the spine of more than 5 vertebrae
• Patients with an active systemic disease such as JIA, HIV, oncologic treatment
• Patients with a previous surgical fusion of the spine
• Patients that are expected to be lost to FU due to e.g. likely to immigrate within 1 year.
• Patients that have had a previous spine surgery.