The safety and efficacy of neuromodulation using percutaneous electrical nerve stimulation for the management of trigeminal‐mediated headshaking in 168 horses

Abstract

Summary Background Early results from the use of neuromodulation by percutaneous electrical nerve stimulation for the management of trigeminal‐mediated headshaking in horses were promising but lacked sufficient case numbers and long‐term follow‐up. The neuromodulatory procedure has since been established as EquiPENS™. Objectives The aim of this study was to report long‐term results from a larger number of cases and to investigate for predictors of outcome. Study design Prospective case series using international, multi‐centre data. Methods Eligible cases were horses with a veterinary diagnosis of trigeminal‐mediated headshaking, which received EquiPENS™ neuromodulation at trained centres between August 2013 and November 2017. The standard protocol was an initial three‐procedure course, with additional procedures should a horse go into remission but then relapse. Data collected included signalment, history, diagnostic tests performed, details of any complications, whether horses had gone into remission and the length of remission. Results Results were obtained from 168 horses, with 530 procedures. The complication rate was 8.8% of procedures. In all but one case, complications were mild and transient, without self‐trauma. Remission of headshaking following the initial course occurred in 53% (72/136) of horses. Median length of time recorded in remission was 9.5 weeks (range 2 days to 156 weeks ongoing). Where signs recurred, most horses went back into remission following additional procedures, usually for longer than from the previous procedure. No predictors for outcome were determined. Main limitations No placebo or control group, owner‐assessed results. Conclusions EquiPENS™ neuromodulation can be an effective and safe treatment for the management of trigeminal‐mediated headshaking in some horses. An increased understanding of neuromodulation could help optimise the technique. Advances in treatment for trigeminal‐mediated headshaking will remain limited until there is a greater understanding of the aetiopathogenesis of the condition.

A Systematic Review of Complementary and Alternative Veterinary Medicine in Sport and Companion Animals: Electrotherapy

“…Two descriptive case series studies were included for analysis in the PENS-related literature review [41,42] (Table 7).…”

In horses with trigeminal-mediated headshaking, is neuromodulation with EquiPENS™ more effective than with electroacupuncture?

“…Similarly, each study had essentially incomplete data sets with some patients lost to follow-up due to illness or injury. Length of followup and cut off times for publishing data meant that some horses that were still in remission had falsely short remission times reported, this was particularly evident in Roberts et al (2020). The strongest evidence was presented by Roberts et al (2020) with larger sample population, longer-term study and assessment of probabilities of outcome and potential hazards.…”

“…Length of followup and cut off times for publishing data meant that some horses that were still in remission had falsely short remission times reported, this was particularly evident in Roberts et al (2020). The strongest evidence was presented by Roberts et al (2020) with larger sample population, longer-term study and assessment of probabilities of outcome and potential hazards. However, all three studies are descriptive case series and provide no control group, blinding or randomisation.…”

Caecal microbiota in horses with trigeminal‐mediated headshaking

“…A variety of treatments with different mechanisms of action and variable results have been used in attempts to alleviate pain in suspected cases (Madigan & Bell, 2001; Pickles et al., 2014). Treatment has included antidepressants, anticonvulsants, channel blockers, antihistamines, corticosteroids, dietary management, facial physical devices, neurectomy or compression of the infraorbital nerve and percutaneous infraorbital nerve electrostimulation (Madigan & Bell, 2001; Mills et al., 2002; Pickles et al., 2014; Roberts et al., 2020). The trigeminal complex is responsible for facial sensation and consists of central (brainstem with relay to the cerebral cortex and first spinal cord segments) and peripheral (trigeminal ganglia and nerve with its multiple branches) parts (Aleman et al., 2013).…”