Frequency distribution in intraoperative stimulation-evoked EMG responses during selective dorsal rhizotomy in children with cerebral palsy-part 2: gender differences and left-biased asymmetry

Comparison of EMG Waveforms versus Degree of Spread in Selective Dorsal Rhizotomy

Selective dorsal rhizotomy (SDR) is a treatment for lower-extremity spasticity in disorders such as cerebral palsy (CP). "Selective" refers to sectioning nerve rootlets with the most abnormal responses on electromyography (EMG) upon intraoperative stimulation. EMG abnormalities can be classified by waveform appearance or by degree of spread throughout lower extremity muscles. We examine the relationship between different EMG waveforms and grades of spread. Intraoperative SDR EMG records from November 2009 through December 2021 were analyzed for waveform types and degrees of spread. Irregular, incremental, multiphasic, sustained, and clonic waveform patterns were considered more abnormal. Decremental, squared decremental, and squared waveforms were less abnormal. Degrees of spread were graded 0-4+, 4+ signifying the most abnormal spread. Distribution of grades of spread was compared between waveform patterns using pairwise Cochran-Armitage tests with Holm-Bonferroni correction. We hypothesized that more abnormal EMG waveform patterns would correlate with higher grades of spread. Sixty-three patients were included, with an average age of 8 years. Most had cerebral palsy (86%, n = 54). The remainder had brain malformations (8%, n = 5) and other etiologies (6%, n = 4). Higher grades of spread significantly increased the likelihood of multiphasic, sustained, or clonic patterns, compared to decremental, irregular, and squared patterns (p < .05). Squared waveforms decreased with higher grades of spread relative to other patterns (p < .05). Different EMG waveform patterns are associated with varying grades of spread in SDR, suggesting that evaluating both waveform pattern and degree of spread together can be useful in guiding rootlet sectioning.

Postoperative outcomes and stimulation responses for sectioned nerve roots during selective dorsal rhizotomy in cerebral palsy

BACKGROUND

Cerebral palsy (CP) is the most cause of motor dysfunction in children. Selective dorsal rhizotomy (SDR) plays a major role in long term spasticity control. However, limited data exists on the effect of SDR on postoperative spasticity treatment requirements and supraspinal effects, and the stimulation responses of dorsal nerve roots in those with CP.

METHODS

The current study included the outcome for 35 individuals undergoing SDR for motor functional outcome, spasticity, baclofen dose changes, botulinum toxin injection frequency, and spasticity related orthopedic procedures. We also report on the stimulation responses in 112 individuals who underwent SDR at our institution.

RESULTS

There was a significant difference in gross motor function measures (GMFM)-66 scores at last follow up that remained present when considering only ambulatory children but not with non-ambulatory children. Ashworth scores were significantly decreased for both upper and lower extremities after SDR at all follow up points. There was a significant decrease in Baclofen dose and botulinum toxin injections requirements after SDR, but no significant difference in the need for orthopedic intervention. A total of 5502 dorsal nerve roots were tested showing a decrease in stimulation intensity and increase in grade on the right side and for descending lumbosacral levels.

CONCLUSIONS

SDR improves gross motor scores during short term follow up but has additional benefits in decreasing baclofen dosing and botulinum toxin injections requirements after surgery. They stimulation responses of sectioned dorsal nerve roots adds to the limited available data and our understanding of the pathological changes that occur in CP.

Dorsal Rhizotomy in the Pediatric Patient

SUMMARY

The majority of cases of dorsal rhizotomy surgeries in children are done to improve the spasticity associated with cerebral palsy, and more recent techniques are selective in nature and referred to as selective dorsal rhizotomy (SDR). The techniques applied to selective dorsal rhizotomy surgery has changed since it was first described and continues to undergo modifications. Approaches to surgery and monitoring vary slightly among centers. This article provides a review of the rationale, variety of surgical approaches, and intraoperative neurophysiologic monitoring methods used along with discussion of the risks, complications and outcomes in these surgeries.

Cerebral palsy and sex differences in children: A narrative review of the literature

In the last years, new evidence has increased the attention on sex differences in the development of children with cerebral palsy (CP). Males seem to present with a higher risk for severe motor impairment and in the response to chirurgical and rehabilitative interventions. The published data confirmed a higher incidence of CP in males than in females. The aim of this literature review was to evaluate the impact of the sex on the most important areas that characterized CP: motor function, comorbidities (pain, cognitive impairment, communications skills, epilepsy, sleep, and behavior), and the different kind of interventions.