Welcome, I am Natasha Romanowski and today we will review Neurolysis for Spasticity Management. I have no disclosures. Today we have the following learning objectives. Identify when to consider Phenol Neurolysis within your treatment plan for spasticity. Analyze potential advantages and disadvantages. Review procedural considerations and common nerves injected. Chemical Neurolysis is an injectable treatment option for the management of focal spasticity. Generally phenol has been used, however, ethyl alcohol is often substituted. For the purposes of this talk, we will focus primarily on phenol as a neurolytic. Historically, phenol is used for the focal management of motor nerves, however, emerging evidence points to effective and safe use in mixed motor sensory nerves as well. We will discuss the risks of this in subsequent slides. Phenol Neurolysis may be used independently or in conjunction with other interventions as part of your treatment plan. Phenol works on the destruction of nerves by denaturing proteins. Phenol works as a neurolytic at concentrations of 5% to 7% while acting as an anesthetic at lower concentrations of 1% to 3%. Although the exact pharmacokinetics remain unknown, phenol is believed to be excreted renally. Advantages of Phenol Neurolysis include its relatively quick onset. A reduction in spasticity can be seen immediately with recent evidence showing continued improvement up to one week. Phenol is also known to have a long duration of action, ranging anywhere from 3 to 12 months. Additionally, in comparison to other injectable interventions, the cost of phenol is relatively low. The effect is generally dose dependent based upon clinical response. And lastly, phenol can be used in attempts to maximize use of neurotoxin elsewhere, especially when used in large muscles innervated by motor nerves. For example, the obturator is a common nerve for phenol neurolysis. And for a patient in which neurotoxin use is also indicated, the toxin could be delivered in larger doses elsewhere by sparing the need for use in the adductors. Despite numerous advantages, phenol has some notable limitations. The procedure requires significant technical skill to perform, which can be challenging given the lack of established protocols outlining the procedure. This can lead to variable efficacy and a variable side effect profile, as safety and efficacy is already less commonly documented in the literature. Having a good understanding of how and when to include phenol neurolysis into your treatment plan should include an understanding of potential risks. Phenol may lead to dysesthesias and prolonged neuropathic pain, especially in nerves with a sensory component. It can also lead to necrosis of surrounding tissue, which can lead to swelling and fibrosis, all of which may lead to muscle or tissue atrophy. The potential adverse effects listed here have a low rate of incidence. However, rare considerations, such as phenol toxicity, must be considered. Unintended toxicity may result in a myriad of complications, including but not limited to cardiovascular arrhythmia, central nervous system depression, end organ damage, and death. Now that you have an understanding of when to consider phenol neurolysis, as well as the safety profile, let's move on to procedural considerations. Once you've identified a patient with focal spasticity who may be amenable to phenol neurolysis, you may want to consider a diagnostic nerve block. This is useful in a diagnostic sense to determine if the nerve in question is contributing to the problem in which you aim to improve. Nerve blocks are useful to evaluate for functional changes once the nerve is blocked to ensure a patient does not lose function. Additionally, it may be useful to investigate spasticity versus contracture prior to planning for more permanent procedures, such as chemical neurolysis or referral for surgical intervention. Diagnostic nerve blocks use short-acting anesthetics delivered perineurally and thus are not long-lasting for spasticity management, but rather for diagnostic considerations only, as there is no permanent effect. When preparing for phenol neurolysis, one must be very familiar with musculoskeletal and neuroanatomy. The nerve or motor branch of interest should be identified, and it is recommended to utilize guidance, either a nerve stimulator or an ultrasound, to ensure accuracy and safety with the procedure. After identifying a nerve and placing your needle, a nerve stimulator works by stimulating the nerve in question. A contraction of the muscle in which it innervates is then noted. The goal is to be able to identify a contraction with minimal current. When this is achieved, injection of phenol then occurs. Additionally, or alternatively, ultrasound guidance can be used to visually identify the nerve for injection while simultaneously monitoring for vasculature in which to avoid. At present, there is no consensus on the amount of phenol in which should be injected. However, emerging literature is beginning to document current practice patterns. Once prepared, phenol has a variable shelf life. It can have as little as a 72-hour shelf life. However, some manufacturers have started creating options for a longer, stable shelf life, up to six months. Phenol is unstable in light and must be stored properly. Institutional protocols should be used for any spillage of the product. As we discussed, common nerves for injection include motor nerves with little to no sensory branches in order to reduce the risk of dysthesias. One common nerve for injection includes the obturator nerve, where phenol neurolysis works to reduce adductor spasticity or scissoring patterns. In the upper extremity, the nerve to the pectoralis can reduce adductor and internal rotation spasticity to the shoulder. And the musculocutaneous nerve can reduce elbow flexor spasticity. An example of a pre- and post-phenol injection to the left obturator nerve is shown. Additionally, mixed nerves have been gaining favor both clinically and within the literature. However, risks of dysthesias due to prominent sensory branches can occur. Neurolysis to the tibial nerve can assist with reduction in spasticity to the ankle and toes, while the sciatic nerve and branches to the hamstring can reduce spasticity in this region. For the upper limb, the median and ulnar nerve can be targeted for spasticity reduction of the forearm, wrist, and finger flexors. Which of the following is true regarding phenol neurolysis? A, it can be useful for focal spasticity management. B, there is a risk of dysthesias or prolonged pain in mixed motor sensory nerves. C, it has a quick onset within minutes. D, all of the above. The correct answer is D. Phenol is commonly used for neurolysis with focal spasticity. It has historically been effective in motor nerves. However, it can be used in mixed motor sensory nerves. There is a risk of dysthesias or prolonged pain. Phenol neurolysis has a quick onset within minutes. In summary, phenol neurolysis can be used to manage focal spasticity. Motor nerves are commonly injected. However, there is emerging evidence for use in mixed motor sensory nerves. Advantages include a relatively quick onset and long duration of effect. Disadvantages include variable efficacy, variable duration, and adverse effects such as pain and dysthesias. A diagnostic nerve block can be considered prior to phenol neurolysis. References are stated. Thank you.

Phenol neurolysis

focal spasticity

nerve denaturation

neuropathic pain

nerve blocks