Phenol is believed to reduce spasticity via direct neurolysis causing damage to the alpha motor fibers of the nerve(s) affected. Phenol neurolysis is not specific for the motor fibers and therefore can cause secondary sensory nerve damage and complications such as painful neuropathy (On et al. 1999). Phenol blocks have been used to successfully treat spasticity in a number of conditions including stroke, SCI, multiple sclerosis and cerebral palsy (Uchikawa et al. 2009; Albert et al. 2002; On et al. 1999; Kirazli et al. 1998; Yadav et al. 1994; Wassef et al. 1993).
Uchikawa et al. (2009) examined the use of phenol blocks for the management of painful shoulder girdle spasticity in persons with cervical level SCI. In an open label, case series, seven individuals with cervical level SCI with shoulder pain and limited range of motion were treated with phenol motor point blocks to the subscapularis muscle. They observed significant improvements in passive ROM in flexion, abduction, and external rotation and decreases in the VAS for shoulder pain (p<0.05 for all). However, they did not observe any significant change in the MAS for shoulder spasticity. The FIM score for eating improved significantly (p<0.05).
In another case series, Yasar et al. (2010) also examined the efficacy of a phenol block on the obturator nerve for the reduction of hip adductor spasticity. The authors reported a statistically significant decrease in spasticity post-treatment.
Ghai et al. (2012) reported a case series of three persons with SCI and hip adductor spasticity treated with phenol blocks of the obturator nerve. Results were variable, with two participants reporting improvement in pain, spasticity, range of motion and hygiene. The other participant reported improvement in pain but not spasticity, and was not satisfied with the results.
Ghai et al. (2013) conducted a pre-post study on the use of phenol blocks of the obturator nerve for the management of hip adductor spasticity in a population that included participants with SCI, multiple sclerosis and Koch’s spine. As SCI participants comprised ≥50% of the samples, and we were unable to obtain patient level data, data pertaining to the entire subject group were included. Ghai et al. (2013) observed significant improvements (p<0.05) in MAS, pain VAS, SFS, range of motion, and hygiene score, which measured the ability of nursing staff to access the perineal area. They reported an improved gait score after neurolysis as measured by the Gait Scale in three ambulatory participants. Inspection of gait after the injection revealed decreased scissoring of hips, improved balance and gait speed. All of them, however, still needed assistive devices for ambulation.
Most recently in a pre-post study, by Demir et. al. (2018), fourteen patients with traumatic spinal cord injury and lower extremity spasticity were treated with ultrasound guided phenol blocks. A total of 19 procedures were reported on. Subjects were reported to have experiences a significant decrease in the modified Ashworth’s score for hip flexors (p < 0.017) and knee extensors (p < 0.017) at one week and two months following treatment. This was associated with reported improvements on ease of catheterization, hygiene, and satification. Spasm frequency decreased significantly in the first week post injection, but was not sustained at the two month evaluations. No complications were reported. This study was limited by small numbers and the lack of a control group.
Alcohol neurolysis works in a manner similar to phenol. It has been studied in the management of spasticity in hemiplegia and in focal dystonias, all with some success. Our literature search failed to reveal any studies utilizing alcohol neurolysis in managing spasticity in SCI.
There is level 4 evidence (from one case series; Uchikawa et al. 2009) that phenol neurolysis improves pain, range of motion and function related to shoulder spasticity for individuals with tetraplegia in SCI.
There is level 4 evidence (from one pre-post study and two case series; Ghai et al. 2013; Ghai et al. 2012; Yasar et al. 2010) that phenol neurolysis reduces hip adductor spasticity in individuals with paraplegia and tetraplegia in SCI.
There is level 4 evidence (from one pre-post study; Demir et. al. 2018) that phenol neurolosis reduces spasticity in the hip flexors and knee extensors with associated improvements in ease of catheterization, hygiene and satisfaction.
There is no literature to support the use of focal neurolysis with alcohol in the management of spasticity in SCI.
Phenol block may improve pain, range of motion and function related to shoulder spasticity in individuals with tetraplegia.
Phenol block may reduce hip adductor spasticity in individuals with paraplegia and tetraplegia.