Session Information
Session Title: AA 2022 Posters - Neurological Rehabilitation
Session Time: None. Available on demand.
Disclosures: Abraham Alfaro, PhD, DO: Owns AbbVie Stock (Products/Services: No) (Stockholder/Ownership Interest (excluding diversified mutual funds))
Objective: To determine if phenol injected onto tibial nerves can decrease sustained ankle clonus and increase ankle dorsiflexion, without causing dysesthesias, for post-stroke patients.
Design: Retrospective study with data analysis by t-tests with repeated measures, and with Wilcoxon Signed Rank Test for ordinal data.
Setting: Outpatient rehabilitation medicine clinic.
Participants: Post-stroke men and women who have sustained ankle clonus.
Interventions: Phenol 5% in water was injected onto the tibial nerve at the popliteal fossa when stimulation at < 1 mA produced strong muscle contractions and ankle dorsiflexion.
Main Outcome Measures: Stimulus current to identify tibial nerves; volume of phenol injected; ankle clonus on the Composite Spasticity Index (CSI with 1=no clonus, 2=clonus < 4 seconds, 3=clonus < 11 seconds, and 4=sustained clonus); ankle dorsiflexion changes with the knee extended (ADFKE) and with the knee flexed (ADFKF) when measured with goniometry; and number of years from the stroke to this injection.
Results: Phenol was injected onto tibial nerves for 44 patients who had sustained ankle clonus; 30 men had 35 injections, and 14 women had 16 injections. The mean ± standard deviation was: age 60.5±11.5 years; 0.46±0.13 mA current to identify tibial nerves when injected; 1.8±1.0 injection sites on tibial nerves; 1.09±0.93 mL of phenol injected per patient and 0.58±0.38 mL per tibial nerve site; -12.2±6.6° ADFKE pre-injection and -4.5±7.1° post-injection with an increase of 7.8±4.9° (P < 0.01); 0±-8.2° ADFKF pre-injection and 6.5±6.7° post-injection for an increase of 6.4±6.0° (p < 0.01); 4±0 CSI for ankle clonus pre-injection and 1.7±1.1 post-injection for a CSI decrease of 2±1.1 (p < 0.001); and 2.56±4.61 years from the stroke to injections. One patient had heel numbness post-injection for three days.
Conclusions: Phenol injections to tibial nerves significantly decreased ankle clonus and increased ankle dorsiflexion. Dysesthesias for only one patient may be due to injections with low phenol volumes, and onto tibial nerves identified with low stimuli.
Level of Evidence: Level III
To cite this abstract in AMA style:
Alfaro A. Phenol Injected Onto the Tibial Nerve at the Popliteal Fossa Decreased Ankle Clonus and Increased Ankle Dorsiflexion [abstract]. PM R. 2022; 14(S1)(suppl 1). https://pmrjabstracts.org/abstract/phenol-injected-onto-the-tibial-nerve-at-the-popliteal-fossa-decreased-ankle-clonus-and-increased-ankle-dorsiflexion/. Accessed May 21, 2025.« Back to AAPM&R Annual Assembly 2022
PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/phenol-injected-onto-the-tibial-nerve-at-the-popliteal-fossa-decreased-ankle-clonus-and-increased-ankle-dorsiflexion/