The Investigators Are Comparing Lidocaine and Papaverine Nerve Blocks to Determine Which Improves Blood Flow Better, Making the "Phoenix Sign" Clearer on Imaging. This Helps Accurately Diagnose Nerve Compression, Improving Patient Care

NCT ID: NCT06919289

Last Updated: 2025-04-09

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

4 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-03-07

Study Completion Date

2024-07-01

Brief Summary

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This pilot study aims to investigate the effects of nerve blocks in patients with diabetic peripheral neuropathy through a double-blinded, randomized trial involving 4 patients. Each participant will receive bilateral peripheral nerve blocks using either lidocaine or papaverine. Following randomization, each patient will receive one medication in one leg and the alternate medication in the contralateral leg. Researchers will measure parameters including motor strength, sensory function (two-point discrimination), arterial blood flow via Doppler ultrasound, and microvascular perfusion using near-infrared spectroscopy both prior to and following nerve block administration. This research seeks to explore potential diagnostic and therapeutic applications for peripheral nerve entrapment, a common yet challenging clinical condition.

Detailed Description

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Detailed Analysis of the Phoenix Sign and Vascular Changes Following Nerve Blocks in Diabetic Neuropathy

Study Background and Purpose

This study investigates the vascular and neurological phenomena associated with peripheral nerve blocks in patients with diabetic neuropathy. The primary aim is to assess whether observed changes following nerve block administration can be attributed to vasodilatory effects of lidocaine or neurological mechanisms.

Common peroneal nerve (CPN) entrapment is the third most common nerve entrapment pathology in humans and frequently results in foot drop, characterized by difficulty lifting the front part of the foot.

Study Design and Methodology

This pilot study is a double-blinded, randomized trial involving 4 diabetic patients presenting bilateral anterior compartment weakness affecting dorsiflexion. All participants will have confirmed diabetic neuropathy with severe sensory impairment.

Key methodological elements:

Randomized administration of 0.5 cc of papaverine HCL (30 mg/ml) or 0.5 cc of 1% lidocaine without epinephrine.

Initial randomization of the first leg via coin toss, with the contralateral leg receiving the alternate medication.

Double-blinded design, ensuring neither patients nor evaluating physicians are aware of medication allocation for each leg.

Ultrasound-guided perineural injection at the fibular neck level.

Comprehensive pre- and post-injection assessments.

Study assessments include:

Macrovascular assessment:

Ultrasound Doppler waveform analysis.

Measurement of blood flow velocity in dorsalis pedis and posterior tibial arteries.

Microvascular assessment:

Kent Snapshot Near-Infrared (NIR) imaging of dorsal and plantar foot surfaces.

Measurement of hemoglobin, deoxyhemoglobin, oxygen saturation (SpO2), and total hemoglobin.

Imaging scheduled pre-injection, at 4 minutes post-injection, and at 10 minutes post-injection.

Motor function assessment:

Movement Against Manual Resistance (MAMR) scored from 1-5 (normalized to 0.2-1.0).

Evaluation of three muscles: extensor hallucis longus (EHL), tibialis anterior (TA), and extensor digitorum longus (EDL).

Dynamometer measurements of EHL muscle strength (Newtons, N).

Sensory assessment:

Two-point discrimination testing

Conditions

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Drop Foot

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

DOUBLE

Participants Investigators

Study Groups

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Lidocaine group

This arm is randomized to the laterality of the subject for either lidocaine or papaverine

Group Type ACTIVE_COMPARATOR

Lidocaine infiltration

Intervention Type DRUG

The study was randomized and double blinded. For randomization, the first extremity had either an infiltration of 0.5 cc of papaverine HCL (30mg/ml) for a 15mg perineural infiltration, or .5 cc of 1% lidocaine without epinephrine determined by a coin toss application.

Papavarine

This arm is randomized to the laterality of the subject for either lidocaine or papaverine, for the first infiltration. The contralateral extremity will then receive the agent that was not administered on the first side from randomization.

Group Type ACTIVE_COMPARATOR

Infiltration of papaverine

Intervention Type DRUG

The study was randomized and double blinded. For randomization, the first extremity had either an infiltration of 0.5 cc of papaverine HCL (30mg/ml) for a 15mg perineural infiltration, or .5 cc of 1% lidocaine without epinephrine determined by a coin toss application.

Interventions

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Infiltration of papaverine

The study was randomized and double blinded. For randomization, the first extremity had either an infiltration of 0.5 cc of papaverine HCL (30mg/ml) for a 15mg perineural infiltration, or .5 cc of 1% lidocaine without epinephrine determined by a coin toss application.

Intervention Type DRUG

Lidocaine infiltration

The study was randomized and double blinded. For randomization, the first extremity had either an infiltration of 0.5 cc of papaverine HCL (30mg/ml) for a 15mg perineural infiltration, or .5 cc of 1% lidocaine without epinephrine determined by a coin toss application.

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* subjects were included if they were diabetic and neuropathic.

Exclusion Criteria

* Patients with Trypanophobia
Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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US Neuropathy Centers

OTHER

Sponsor Role lead

Responsible Party

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Stephen Barrett

US Neuropathy Centers Medical Director

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

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Indiana Foot and Ankle

Jasper, Indiana, United States

Site Status

Countries

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United States

References

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Barrett SL, Boyd B, DuCasse S, Nassier W, Mitchell N, Nagra AP, Dalmau-Pastor M, Yamasaki DS, Nickerson S. 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. BMC Musculoskelet Disord. 2024 Oct 23;25(1):840. doi: 10.1186/s12891-024-07972-3.

Reference Type BACKGROUND
PMID: 39443927 (View on PubMed)

Other Identifiers

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USNC-2025-3

Identifier Type: OTHER

Identifier Source: secondary_id

JIN-2025-0326

Identifier Type: -

Identifier Source: org_study_id

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