Is the phoenix sign phenomenon due to vasodilation? A double-blinded, randomized controlled trial comparing motor function recovery after diagnostic common fibular nerve block with lidocaine and papaverine.

Autor: Barrett SL; Neuropathy Centers, Marietta, GA, USA. slbarrettpod@me.com., Boyd B; Neuropathy Centers, Marietta, GA, USA., DuCasse S; Neuropathy Centers, Marietta, GA, USA., Nassier W; Neuropathy Centers, Marietta, GA, USA., Mitchell N; Neuropathy Centers, Marietta, GA, USA., Nagra AP; Neuropathy Centers, Marietta, GA, USA., Dalmau-Pastor M; Human Anatomy and Embryology Unit, Department of Pathology and Experimental Therapeutics, School of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain.; MIFAS by GRECMIP (Minimally Invasive Foot and Ankle Society), Merignac, France., Yamasaki DS; Enso Medical Technologies Inc, St. Augustine, FL, USA., Nickerson S; NE Wyoming Wound Care Clinic, Sheridan, WY, USA.
Jazyk: angličtina
Zdroj: BMC musculoskeletal disorders [BMC Musculoskelet Disord] 2024 Oct 23; Vol. 25 (1), pp. 840. Date of Electronic Publication: 2024 Oct 23.
DOI: 10.1186/s12891-024-07972-3
Abstrakt: Background: Focal entrapment of the common fibular (peroneal) nerve (CFN) is the most common nerve entrapment in the lower extremity. Accurate diagnosis can be difficult due to co-existent pathology such as low back pathology. A 1% lidocaine block of CFN is often used to confirm the local entrapment pathology and demonstrate possibility of pain relief. A surprising, unexpected and temporary strengthening of CFN supplied ankle and foot muscles is occasionally produced, termed the Phoenix sign. Aetiology of this phenomenon has been puzzling, but restoration of neural circulation and nutrition via improved local blood flow has been postulated to be responsible.
Methods: This is a double-blinded, randomized, prospective controlled trial of 20 patients, comparing 2 vasodilating agents and their ability to produce the Phoenix effect. Ultrasound guided infiltration of 0.3 mL 1% lidocaine or papaverine HCl 10 mg/mL was executed adjacent to CFN. Motor strength pre- infiltration and 4 min post-infiltration were measured for anterior compartment muscles utilizing MRC manual motor testing reported on a 0-5 scale. The extensor hallucis longus (EHL) muscle proved to be the most significant.
Results: Average motor strength of the EHL improved from 2.2 (+/-0.40) to 4.9 (+/-0.32).) in the lidocaine group. In the papaverine group, pre-infiltration EHL motor strength averaging 2.1 (+/-0.93) improved to 4.4 (+/- 1.01) post-infiltration. Papaverine and lidocaine produced similar statistically significant increases in muscle strength (p = < 0.05).
Conclusion: There was no difference between small local infiltrations of lidocaine or papaverine in production of increased anterior compartment EHL motor strength. It is most likely that the Phoenix Effect is explained by temporary local improvements in the microcirculation of the CFN vasa nervorum.
Trial Registration: NCT06637046 10/10/2024 Retrospectively registered.
(© 2024. The Author(s).)
Databáze: MEDLINE
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