# Lumbosacral Endoscopic Ventral–Dorsal Rhizotomy: A Novel Approach for Tone Reduction

## TL;DR

This paper introduces a new minimally invasive surgical technique for reducing muscle tone in patients with severe, treatment-resistant hypertonia.

## Contribution

The first reported case series of lumbosacral endoscopic ventral–dorsal rhizotomy (eVDR) for medically refractory hypertonia.

## Key findings

- eVDR was safely performed in four patients with severe rotatory scoliosis and fusion hardware.
- Significant reductions in muscle tone and dystonia scores were observed post-surgery.
- Patients experienced short hospital stays and minor perioperative events without additional surgeries.

## Abstract

Objective: Neurosurgical interventions for medically refractory hypertonia (MRH) benefit both patients and their caregivers. Concurrent severe rotatory scoliosis and fusion constructs can make traditional microsurgical rhizotomy and navigated radiofrequency ablation (RFA) peripheral rhizotomy technically infeasible. We report the first case series of lumbosacral endoscopic ventral–dorsal rhizotomy (eVDR) in patients with MRH, and highlight this novel, minimally invasive, safe, and effective technique. Material and Methods: We retrospectively reviewed our single institution series of four patients with advanced hypertonia, gross motor function classification scale (GMFCS) 5, and severe rotatory scoliosis who underwent an eVDR using a flexible endoscope. We report demographics, operative characteristics, and outcomes. Results: Four patients underwent bilateral L1-S1 eVDR. Two patients had spastic quadriplegia and two had mixed spastic and dystonic hypertonia. Mean operative time was 225 ± 11 min and mean estimated blood loss (EBL) was 28.8 ± 26.2 mLs. Average length of stay was 2.75 days (range = 1–5 days), and average follow-up was 5.75 months (range = 3–9 months). All patients had significant decrease in bilateral lower extremity modified Ashworth Scale (mAS) scores (median decrease = 3, interquartile range [IQR] = 1; Wilcoxon rank-sum test z = −2.3, p = 0.02). The median decrease in Barry–Albright Dystonia Scale (BADS) scores for both patients with dystonia was 8 (IQR = 0). Two patients had minor perioperative events; none required additional surgery. All parents reported improvement in caregiving metrics. Conclusions: eVDR offers a safe and effective approach for tone reduction in patients with MRH and severe rotatory scoliosis and/or fusion hardware, which disallows traditional approaches.