Ultrasound-guided ethyl alcohol injection to the deep branch of the ulnar nerve to relieve hand spasticity in stroke patients: A case series.

Min Cheol Chang,Mathieu Boudier-Revéret,Gyu-Sik Choi

doi:10.1515/tnsci-2020-0188

Abstract

Hand spasticity with a flexor pattern is a common problem affecting stroke patients and can result in pain, contractures, esthetic concerns, skin maceration, and overall loss of function. Poststroke (≥6 months) hemiparetic adult patients having a Modified Ashworth Scale (MAS) score of ≥1 for metacarpophalangeal flexion and thumb adduction spasticity were selected to receive an ultrasound-guided 20% ethyl alcohol block performed perineurally at the level of the deep branch of the ulnar nerve. Their MAS scores were evaluated pretreatment at 1 month and the change in MAS scores was assessed using Wilcoxon’s test. The threshold for statistical significance was set at p < 0.05. The mean MAS score for the flexor muscles of the 5 MCP joints and for thumb adduction was reduced from 3.3 ± 0.5 at pretreatment to 0.9 ± 0.5 at 1 month after the injection for the 10 patients. One month after the injection, the MAS scores were significantly reduced compared with those at pretreatment (p < 0.001), without complications. These are encouraging results showing that ultrasound-guided alcohol blocks of the deep branch of the ulnar nerve are safe and can help chronic stroke patients with metacarpophalangeal flexion and thumb adduction spasticity at 1 month.

Highlights

Hand spasticity with a flexor pattern is a common problem affecting stroke patients and can result in pain, contractures, esthetic concerns, skin maceration, and overall loss of function
In 1987, Keenan et al reported successful treatment of intrinsic spasticity in the hands of stroke patients with phenol neurolysis of the deep branch of the ulnar nerve (DBUN), which is responsible for motor innervation of most of the intrinsic muscles of the hand, employing an open motor branch block in Guyon’s canal by exposing surgically the DBUN and injecting it subepineurally with a 5% solution of phenol in glycerine [5]
We used Modified Ashworth Scale (MAS) scores to assess the degree of spasticity in the flexor muscles of the five MCP joints and of thumb adductors: 0, no increase in muscle tone; 1, slight increase in muscle tone manifested by a catch and release or by minimal resistance at the end of the range of motion (ROM) when the affected part(s) was(were) moved in flexion or extension; 1+, slight increase in muscle tone manifested by a catch, followed by minimal resistance throughout the remainder of the ROM; 2, a more marked increase in muscle tone through most of the ROM, but affected part(s) moved; 3, considerable increase in muscle tone, passive movement difficult; 4, affected part(s) rigid in flexion or extension

Summary

Description of case series

We prospectively recruited ten stroke patients among the patients who visited the university hospital or the local rehabilitation clinic for a routine follow-up after discharge after inpatient rehabilitation treatment. Hemiparetic stroke patients were recruited into this study according to the following inclusion criteria: (1) ≥6 months after stroke onset, (2) finger flexor and thumb adduction spasticity (a Modified Ashworth Scale [MAS] score of ≥1), (3) age ≥20 years old, (4) no history of peripheral nerve injury, and (5) no history of any invasive procedure (injection of botulinum toxin, alcohol, or phenol) for the treatment of spasticity for at least 6 months before the initiation of this study. Ethyl alcohol injection and follow-up after the injection were performed in the university hospital for all the included patients. Informed consent: Informed consent has been obtained from all individuals included in this study

Clinical evaluation

Statistical analysis

Findings

Discussion