Objective: To present practice patterns for phenol neurolysis procedures conducted for spasticity management.
Design: A retrospective review of 185 persons with spasticity who underwent phenol neurolysis procedures (n = 293) at an academic rehabilitation hospital and clinic. Patient demographics, concomitant spasticity treatments, and procedure relevant information were collected.
Results: The cohort included 71.9% males and 61.6% inpatient procedures. Neurological diagnoses included stroke (41.0%), traumatic brain injury (28.6%) and spinal cord injury (24.3%). Musculoskeletal diagnoses included spastic hemiplegia or paresis (51.3%), tetraplegia (38.4) and paraplegia (9.2%). At the time of phenol neurolysis, most patients (77.5%) received concomitant pharmacological treatments for spasticity. Injection guidance modalities included electrical stimulation and ultrasound (69.3%) or ultrasound only (27.3%). A mean of 3.48 ml of phenol were injected per nerve and 10.95 ml of phenol were used per procedure. Most commonly injected nerves included the obturator nerve (35.8%) and sciatic branches to the hamstrings and adductor magnus (27.0%). Post-phenol neurolysis assessment was recorded in 54.9% of encounters, in which 84.5% reported subjective benefit. Post-procedure adverse events included pain (4.0%), swelling and inflammation (2.7%), dysaesthesia (0.7%) and hypotension (0.7%).
Conclusion: Phenol neurolysis is currently used to reduce spasticity for various functional goals, including preventing contractures and improving gait. Depending on the pattern of spasticity displayed, numerous peripheral nerves in the upper and lower extremities can be targeted for treatment with phenol neurolysis. Further research into its role in spasticity management, including studies exploring its cost-effectiveness and pharmacological and side-effects compared with other treatment options are needed.
Characterized by hyperexcitable stretch reflexes that increase muscle tonicity and exaggerate tendon jerks, spasticity is a common motor disorder that follows a variety of central nervous system insults (1). Implicated neurological insults most often include stroke, traumatic brain injury (TBI) or spinal cord injury (SCI). Spasticity is often associated with various complications including joint contractures, muscle shortening and postural deformities (1) that lead to multiple impairments. Early goal-directed spasticity management is instrumental in helping increase the likelihood of good outcomes and limiting complications (1, 2). Unfortunately, a lack of universally standardized management and an abundance of therapeutic options make spasticity management a challenging task.
Currently, spasticity is frequently managed through a combination of therapeutic modalities, pharmaceutical options and surgical procedures (3). Pharmaceutical options include medications delivered orally, via local injections, or through intrathecal pumps. Oral medications, including baclofen and tizanidine, help decrease spasticity (3). However, systemic side-effects, such as generalized muscle weakness, sedation, confusion, and hypotension, preclude the use of higher dosages that might be warranted for control of moderate-to-severe spasticity (3, 4). Intrathecal baclofen pump (ITB) is often indicated in treating severe and/or diffuse spasticity as a means to deliver high-dosage baclofen with less concern for systemic side-effects (4). Although ITB treatment is very effective, numerous complications and the requirement for commitment to maintenance associated with this treatment makes it favourable only for some patients with severe spasticity (4, 5).
Chemoneurolysis via localized injections can help provide focal spasticity relief (1, 3, 6). In addition, the use of single-event multi-level chemoneurolysis helps treat several areas of muscle spasticity, each with varying severities (7). Medications used in chemo-neurolysis procedures include botulinum neurotoxin (BoNT), phenol, and alcohol neurolysis (3–7). Compared with phenol and the understudied alcohol neurolysis, BoNT usage in treating spasticity is documented extensively in the literature with regards to pharmacodynamics, adverse effects and clinical benefits (7–9). However, the response to chemodenervation with BoNT often requires 3–5 days to generate spasticity benefit, which generally lasts approximately 3 months. Although clinical standards permit repeating chemodenervation every 3 months, the majority of patients with spasticity prefer an increased frequency for maintaining clinical benefit (10–12). BoNT injections are associated with significant costs, and repeated injections are often further restricted by financial feasibility. In the USA, depending on the insurance being used, the approved dosage of BoNT is only 400–600 units of every 3 months. These limitations prevent the sole utility of chemodenervation for a multi-pattern treatment, e.g. elbow flexion, clenched fist, stiff knee gait, and equinovarus of the foot. Consequently, phenol neurolysis (PN) and BoNT are used in complement, with PN frequently reserved for proximal nerves and BoNT used for distal musculature.
In contrast, PN produces an almost-immediate effect that manifests within minutes of injection, which may last as long as 6 months depending on the dosage used (1, 13). In addition, PN is significantly less expensive. PN may also be re-injected before 3 months, unlike BoNT. However, the safety and efficacy of PN is less-commonly documented in the literature than BoNT chemodenervation. PN also requires a higher level of expertise to administer, and has a worse side-effect profile, which includes hypotension, prolonged pain, dysaesthesias, site inflammation, and joint fibrosis (1, 13, 14). These disadvantages for phenol usage are associated with safety concerns relative to neurotoxins, thus making BoNT a vastly more popular option for chemoneurolysis. Phenol is therefore being used increasingly less in the USA and is poorly documented in the spasticity literature. Given its advantages, PN may be superior to chemodenervation with BoNT in certain clinical scenarios. Thus, the primary purpose of the current study is to describe the utilization pattern of PN at a single site.