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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).

Table 28 Phenol Neurolysis for Reducing Spasticity

Author Year

Country
Research Design

Score
Total Sample Size

MethodsOutcome
 Demir et al. 2018

Turkey

Pre-Post

N=19

 

Population: SCI (n=19): Mean age=33±9.4yr; Gender: males=11, females=3; Level of injury: C=8, T=6; Mean time since injury=90.7±104.5mo; AIS scale: A=6, B=5, C=2, D=1.

Intervention: All participants received 19 ultra sound-guided femoral nerve block. Femoral neurolysis was performed with a peripheral nerve stimulator with a frequency of 1 Hz for 0.1 ms. Initial intensity was 3 mA. Three mL of 5% phenol was administered to the perineural area after stimulation. Outcome measures were assessed at baseline, end of the 1st wk, and at the end of the 2nd mo.

Outcome Measures: modified Ashworth Scale; frequency of spasms; satisfaction.

1.     There were significant decreases in mAS scores of hip flexor muscle tone at 1st wk and 2nd mo follow-up assessments when compared to baseline (p<0.017).

2.     There was were significant decreases in spasticity in the mAS score of knee extensor tone at end of 1st wk and 2nd mo when compared to baseline (p<0.017).

3.     There were significant increases in participant satisfaction regarding intervention at 1st wk and 2 mo follow-ups when compared to baseline. Moreover, satisfaction improved significantly from 1st wk to 2nd mo follow-up (p<0.017).

 

Ghai et al. 2013

India

Pre-Post

N=20

Population: Mean age: 36.7 yr; Gender: males=17, females=3; Injury etiology: SCI=16, koch’s spine=2, MS=2.

Intervention: 10 ml of 0.25% bupivacaine. If 1° MAS decrease and 20° range of motion increase were observed, obturator nerve blockade with 8-10 ml of 6% phenol was performed using the interadductor approach the next day. Outcomes were assessed at the 1st hr, 24th hr, end of 1st wk, and 1st, 2nd, and 3rd mo post intervention.

Outcome Measures: Modified Ashworth Scale (MAS), Visual Analog Scale (VAS), Spasm Frequency Scale (SFS), Range of Motion (ROM), Hygiene score, Gait scale score.

1.       All parameters with the exception of gait significantly improved (p<0.05) compared with the baseline during all time periods between 1 hr and 3 mo post intervention.

2.       Gait score showed significant improvement (p<0.05) compared with the baseline between 1 wk and 3 mo post treatment. There was no significant improvement in gait score before 1 wk.

3.       Adverse events: 2 participants developed dysesthesia lasting for 7 to 10 days; 1 participant developed fibrosis at the injection 20 days post-injection; no participants developed neuritis or secondary deafferentation pain

Ghai et al. 2012
India
Case Series
N=3
Population: Mean age: 18.3 yr; Gender: males=3, females=0; Level of injury: T4-6=2, C4-5=1; Level of severity: AIS D=3.

Intervention: 8-10 ml 65% alcohol to obturator nerves with interadductor approach after successful 10 ml of 0.5% bupivacaine block.

Outcome Measures: ROM, Pain Visual Analog Scale (VAS), Modified Ashworth Scale (MAS), Hygiene. Outcomes assessed at 1 wk, 3 mo and 4 mo post injection.

 

1 wk post-injection:
Case 1:
“Drastic” improvements in hip joint ROM, pain VAS, MAS, hygiene
Duration of improvements: 3 mo for ROM, MAS, hygiene; 4 mo for pain VAS
Case 2: “There was significant improvement in pain,
spasticity, range of motion of hip joint, hygiene scores, and number of muscle spasms. It has been 6mo now, and the effect of alcohol is still persisting”
Case 3:
“Though the VAS score decreased significantly but spasticity and numbers of spasms were not much alleviated, and the participant was quite unsatisfied with the block”
Yasar et al. 2010

Turkey

Retrospective Case Series

N=20

Population: Mean age: 42.9 yr; Gender: males=19, females=1; Injury etiology: traumatic, non-traumatic SCI; Level of injury: tetraplegia=3, paraplegia=17; Level of severity: AIS A=13, AIS B=7; Mean time since injury: 41.8 mo.

Intervention: Phenol obturator nerve blockade.

Outcome Measures: Hip adductor spasticity.

1.      Mean hip adductor spasticity decreased significantly after (p<0.001).

 

Uchikawa et al. 2009

Japan

Case Series

N=7

Population: Mean age: 55.8 yr; Gender: males=7, females=0; Injury etiology: SCI=7; Level of injury: C5=5; Time since injury: ≥5 mo.

Intervention: Subscapular phenol nerve block.

Outcome Measures: Shoulder Range of Motion (ROM), Visual Analog Scale (VAS) for pain, Ashworth Scale (AS), Eating functional independence measure item score.

1.     Significant improvements in passive ROM in flexion (23.71), abduction (19.41) and external rotation (16.81; p<0.05)

2.     Decreases in the VAS for shoulder pain which was reduced from 6.0 to 3.4 (p<0.05).

3.     No significant change in the MAS for shoulder spasticity.

4.     Eating Functional Independence Measure item score improved significantly (p<0.05).

Discussion

Phenol

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

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.

Conclusions

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.