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 (p<0.01) by 11° at initial contact, 9° to 10° in stance phase, and 4° in swing phase. Sagittal plane ankle kinematics improved more for the cauda group than the conus group in both stance phase (10° vs 2°, p<0.01) and swing phase (13° vs 3°, p<0.01). 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. What this paper adds: Conus and cauda selective dorsal rhizotomy (SDR) resulted in mostly similar short-term gait and functional outcomes. Conus SDR resulted in residual equinus dynamically, despite normalized spasticity measures. Post-surgical complications were mostly similar between SDR techniques.