Cerebral palsy or CP is the single largest cause of childhood physical disability, with a prevalence of 2-3 per 1000 livebirths. Children with CP experience different primary symptoms, including abnormal increased muscle tone or spasticity. Selective dorsal rhizotomy (SDR) is applied in children with spastic CP as a non-reversible tone reduction procedure. Better understanding of the effects of SDR on a multidimensional outcome set in one CP-cohort and on macroscopic muscle morphology can improve insights and clinical decision making.

Cerebral palsy or CP is the single largest cause of childhood physical disability, with a prevalence of 2-3 per 1000 livebirths. Children with CP experience different primary symptoms, including abnormal increased muscle tone or spasticity. Selective dorsal rhizotomy (SDR) is applied in children with spastic CP as a non-reversible tone reduction procedure. During this neurosurgical procedure, dorsal rootlets are transected to diminish the excitatory input from the afferents, resulting in a reduction of the abnormal, increased muscle tone. Although different studies investigated the SDR-effect on separate sets of outcomes, such as spasticity, gait or gross motor function, no study so far has studied SDR-effects on combined outcome sets in one CP-cohort or on macroscopic muscle morphology.

The discrepancy between results of different previous studies highlight the added value of a multidimensional outcome set assessed within one cohort. Integrating outcomes of different levels will provide a better insight on how effects do or do not occur. Additionally, although SDR does not directly intervene with the macroscopic muscle structures, reducing the excitatory input from the afferents could potentially have an effect on muscle growth. Indicating macroscopic muscle morphology as an important outcome.

The current study will investigate the added value of a multidimensional outcome set, assessed in one single cohort. Important gaps in the literature will be addressed, including the effect of SDR on muscle morphology and the use of instrumented assessments. The primary objective of this study was to investigate changes in a multidimensional outcome set (including spasticity, muscle morphology, gait and gross motor function) pre- and post-SDR, in one single cohort of children with spastic CP. As a secondary objective, this study will compare outcomes of the clinical examination (spasticity, range of motion, strength, selectivity) pre- and post-SDR. Additionally, muscle morphology will be qualitatively compared in children with CP who received an SDR to children with CP without an SDR intervention.

Inclusion Criteria:

• Spastic CP, Uni- or bilateral involvement
• Gross Motor Classification System (GMFCS) levels I to III
• Children: 5 to 16 years of age at time of SDR
• SDR intervention
• Clinical follow-up pre- and post-SDR at the Clinical Motion Analysis Laboratory Pellenberg (CMAL, UZ Leuven, Campus Pellenberg)

Exclusion Criteria:

• Presence of dystonia or ataxia
• SDR intervention in combination with muscle surgery
• Severe co-morbidities (that are likely to prevent proper assessment, such as severe cognitive problems)

Children with spastic cerebral palsy, receiving SDR at the CP reference center of the University Hospitals Leuven and have clinical follow-up pre- and post-SDR at the Clinical Motion Analysis Laboratory Pellenberg (CMAL, UZ Leuven, Campus Pellenberg)

Control groups:

• Reference database of children with spastic cerebral palsy, without a SDR intervention
• Reference database of typically developing children