Comparing short-term outcomes between conus medullaris and cauda equina surgical techniques of selective dorsal rhizotomy

Aim To compare short-term outcomes between conus medullaris (conus) and cauda equina (cauda) selective dorsal rhizotomy (SDR) techniques in children with spastic cerebral palsy. Method This was a retrospective review of SDR at a single center from 2013 to 2017. Gait and functional outcome measures were assessed at no more than 18 months pre-SDR (baseline) and 8 to 36 months post-SDR (follow-up). Transient complications during inpatient stay were quantified. Results In total, 21 and 59 children underwent conus and cauda SDR respectively. Ashworth Scale scores were nearly normalized at follow-up. Most physical examination and functional measures exhibited similar baseline to follow-up responses for both groups. From baseline to follow-up, sagittal plane knee kinematics for both groups significantly improved (p0.01) by 11 degrees at initial contact, 9 degrees to 10 degrees in stance phase, and 4 degrees in swing phase. Sagittal plane ankle kinematics improved more for the cauda group than the conus group in both stance phase (10 degrees vs 2 degrees, p0.01) and swing phase (13 degrees vs 3 degrees, p0.01). Post-surgical complications were similar between groups. Interpretation Conus and cauda SDR techniques resulted in similar short-term outcomes except in ankle kinematics at follow-up. The cauda group exhibited a large improvement towards dorsiflexion, while there was residual equinus in the conus group despite Ashworth Scale scores normalizing equally in both groups.