title: Increased electrical nerve stimulation threshold of the sciatic nerve in patients with diabetic foot gangrene: a prospective parallel cohort study.
abstract: BACKGROUND
  Peripheral neuropathy may affect nerve conduction in patients with diabetes mellitus.
  
  
  OBJECTIVE
  This study was designed to test the hypothesis that the electrical stimulation threshold for a motor response of the sciatic nerve is increased in patients suffering from diabetic foot gangrene compared to non-diabetic patients.
  
  
  METHODS
  Prospective non-randomised trial with two parallel groups.
  
  
  METHODS
  Two university-affiliated hospitals.
  
  
  METHODS
  Patients scheduled for surgical treatment of diabetic foot gangrene (n = 30) and non-diabetic patients (n = 30) displaying no risk factors for neuropathy undergoing orthopaedic foot or ankle surgery.
  
  
  METHODS
  The minimum current intensity required to elicit a typical motor response (dorsiflexion or eversion of the foot) at a pulse width of 0.1 ms and a stimulation frequency of 1 Hz when the needle tip was positioned under ultrasound control directly adjacent to the peroneal component of the sciatic nerve.
  
  
  RESULTS
  The non-diabetic patients were younger [64 (SD 12) vs. 74 (SD 7) years] and predominantly female (23 vs. 8). The geometric mean of the motor stimulation threshold was 0.26 [95% confidence interval (95% CI) 0.24 to 0.28] mA in non-diabetic and 1.9 (95% CI 1.6 to 2.2) mA in diabetic patients. The geometric mean of the electrical stimulation threshold was significantly (P < 0.001) increased by a factor of 7.2 (95% CI 6.1 to 8.4) in diabetic compared to non-diabetic patients.
  
  
  CONCLUSIONS
  The electrical stimulation threshold for a motor response of the sciatic nerve is increased by a factor of 7.2 in patients with diabetic foot gangrene, which might hamper nerve identification.
authors.affiliation: Department of Anaesthesiology, Heart Centre Freiburg University, Bad Krozingen, Germany. cornelius.keyl@universitaets-herzzentrum.de
authors.forename: Cornelius
authors.initials: C
authors.lastname: Keyl
authors.forename: Tanja
authors.initials: T
authors.lastname: Held
authors.forename: Georg
authors.initials: G
authors.lastname: Albiez
authors.forename: Astrid
authors.initials: A
authors.lastname: Schmack
authors.forename: Christoph
authors.initials: C
authors.lastname: Wiesenack
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000503:physiopathology; D017719:Diabetic Foot / Q000628:therapy; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D005528:Foot / Q000294:innervation* / Q000601:surgery; D005734:Gangrene / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D009431:Neural Conduction; D017288:Pain Threshold; D011446:Prospective Studies; D012307:Risk Factors; D012584:Sciatic Nerve / Q000502:physiology* / Q000503:physiopathology