Peripheral Nerve Stimulation in Diabetic Patients

Influence of Diabetic Neuropathy on Current Settings During Peripheral Nerve Stimulation in Regional Anesthesia

The prevalence of diabetes mellitus (DM) in industrialized countries is estimated to be about 7.3% and its incidence has been growing in recent years. The prevalence of diabetic neuropathy in the diabetic patient population is up to 50%. When limb surgery is necessary, it is reasonable to assume that diabetic patients will benefit from a peripheral regional anesthesia because of the severe comorbidities associated with DM. On the other hand, the use of regional anesthesia (RA) has generally not been recommended in patients with preexisting neuropathies mainly because of medical liability issues, as worsening neuropathy could be attributed to nerve damage caused by the regional anesthetic. The current state of the art of peripheral regional anesthesia for the identification of correct placement of an injection needle suitably close to the target nerve is to elicit a motor response by current injection through the needle. Constant reduction of the current as the nerve is approached ensures close proximity so that an effective nerve block is obtained when the local anesthetic is delivered through the needle, and absence of a motor response at 0.3 mA is generally accepted as a safety marker to avoid harmful intraneural injection. An important deficit in our understanding is whether diabetic neuropathy influences the stimulation parameters for peripheral nerve stimulation (PNS), possibly decreasing safety.

The currently proposed research is guided by the hypothesis that nerves in patients with DM are more resistant to stimulation and the current thresholds for PNS have to be set much higher to prevent injections from occurring within the epineurium. The investigators will examine the effect of DM on nerve excitability in a blinded, prospective, observational case control trial. Accordingly, the investigators have defined following aims:

Specific Aim 1: To characterize the required stimulation current in patients with and without diabetes mellitus.

Specific Aim 2: Follow-up to examine if the rate of adverse neurologic events is higher in diabetic patients.

Specific Aim 3: Guided by the results, formulate recommendations for the performance of regional anesthesia in patients with a history of DM.

These experiments will provide better understanding of the needle-current-nerve relationship during peripheral nerve stimulation. Findings from this study will have a major impact on patient safety, especially in the subgroup with preexisting neuropathy, undergoing regional anesthesia.

Study Overview

• Status: Completed
• Conditions: Diabetic Polyneuropathy
• Intervention / Treatment: Procedure: peripheral nerve stimulation

• Study Type: Observational
• Enrollment (Actual): 124

Contacts and Locations

Study Locations

• Austria
  • Graz, Austria, 8036
    • Medical University of Graz

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

Surgical patients scheduled for lower limb surgery and are eligible for a popliteal sciatic nerve block

Description

Inclusion Criteria:

• Patients of both sexes
• age more than 18 years
• American Society of Anesthesiology status 1 to 4
• signed informed consent

Exclusion Criteria:

• Pregnancy
• Allergies to local anesthetics
• Unwillingness or incapability to sign informed consent
• Any preexisting neurological deficit of the lower limb that cannot be attributed to diabetic neuropathy
• Ongoing dual anti-platelet therapy

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Diabetes Mellitus (DM); Patients with diagnosed diabetes mellitus type 1 or 2 undergoing surgery of the lower limb and are receiving regional anesthesia with peripheral nerve stimulation	Procedure: peripheral nerve stimulation; defining the minimal current threshold for distal motor response
Control (C); Patients with no history of diabetes mellitus Type 1 or 2 undergoing surgery of the lower limb and are receiving regional anesthesia with peripheral nerve stimulation	Procedure: peripheral nerve stimulation; defining the minimal current threshold for distal motor response

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Minimal current threshold for distal motor response at needle tip nerve contact	18 months

Collaborators and Investigators

• Sponsor: Medical University of Graz
• Investigators: Principal Investigator: Marcel Rigaud, PD, MD, Medical University of Graz

Publications and helpful links

General Publications

• Heschl S, Hallmann B, Zilke T, Gemes G, Schoerghuber M, Auer-Grumbach M, Quehenberger F, Lirk P, Hogan Q, Rigaud M. Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block. Br J Anaesth. 2016 Apr;116(4):538-45. doi: 10.1093/bja/aew027.

Study record dates

Study Major Dates

• Study Start: January 1, 2012
• Primary Completion (ACTUAL): December 1, 2013
• Study Completion (ACTUAL): December 1, 2013

Study Registration Dates

• First Submitted: December 2, 2011
• First Submitted That Met QC Criteria: December 6, 2011
• First Posted (ESTIMATE): December 8, 2011

Study Record Updates

• Last Update Posted (ESTIMATE): January 30, 2015
• Last Update Submitted That Met QC Criteria: January 29, 2015
• Last Verified: January 1, 2015

More Information

Terms related to this study

• Keywords: diabetes; regional anesthesia; diabetic neuropathy; peripheral nerve stimulation
• Additional Relevant MeSH Terms: Nervous System Diseases; Endocrine System Diseases; Diabetes Complications; Diabetes Mellitus; Neuromuscular Diseases; Peripheral Nervous System Diseases; Polyneuropathies; Diabetic Neuropathies
• Other Study ID Numbers: KLI 135