Disclosures: Victoria L. Heasley, MD: No financial relationships or conflicts of interest

Case Description: 18-year-old male with history of bilateral pesplanovalgus deformity who underwent left flatfoot reconstruction in December 2016 with lateral column lengthening, accessory navicular excision, strayer procedure complicated by continued left lateral ankle pain.

Setting: Academic Institute

Patient: The patient experienced left lateral foot pain and was evaluated by an Orthopedic surgeon in 2018. He was advised to repeat formal physical therapy and continue to wear orthotics and bilateral AFOs. By March 2019, he experienced acutely worsened pain without inciting incident. His lateral left ankle pain was worse with weight bearing and hypersensitive to light touch. There was concern for a sural mononeuropathy, and he was referred to PM&R for ultrasound-guided sural nerve block with local anesthetic.
A diagnostic block of the left sural nerve was done with 1.5 ml of 0.5% bupivacaine and 1.5 ml of 1% lidocaine under ultrasound-guidance. The patient reported pain improvement and two months later requested a second injection, which was done with 2 ml of 1% lidocaine and 40 mg Kenalog under ultrasound-guidance. He had pain relief for ~45 days, but he started to notice the pain returning, subsequently making work difficult to tolerate. The decision was made to trial repeat sural nerve block with Phenol rather than sural neurotomy. This was done in July 2019 using 5 ml of 6% Phenol and 2 ml of 1% lidocaine. Assessment/

Results: Patient reported pain relief for 6 months and called for another Phenol injection.

Discussion: To our knowledge, this is the first reported use of Phenol for a sural nerve block to treat post-surgical pain and hypersensitivity.

Conclusion: Ultrasound-guided injection of the sural nerve with Phenol can be used to significantly decrease pain for at least 6 months or as a pre-surgical test to estimate benefits and results of a neurotomy.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/sural-nerve-block-under-ultrasound-guidance-with-phenol/