title: Can surface electromyography improve surgery planning? Electromyographic assessment and intraoperative verification of the nerve bundle entry point location of the gracilis muscle.
abstract: OBJECTIVE
  To verify the precision of surface electromyography (sEMG) in locating the innervation zone of the gracilis muscle, by comparing the location of the IZ estimated by means of sEMG with in vivo location of the nerve bundle entry point in patients before graciloplasty procedure due to fecal incontinence.
  
  
  METHODS
  Nine patients who qualified for the graciloplasty procedure underwent sEMG on both gracilis muscle before their operations. During surgery the nerve bundle was identified by means of electrical stimulation. The distance between the proximal attachment and the nerve entry point into the muscle's body was measured. Both measurements (sEMG and in vivo identification) were compared for each subject.
  
  
  RESULTS
  On average, the IZ was located 65.5mm from the proximal attachment. The mean difference in location of the innervation zones in each individual was 10±9.7mm, maximal - 30mm, the difference being statistically significant (p=0.017). It was intraoperatively confirmed, that the nerve entered the muscle an average of 62mm from the proximal attachment. The largest difference between the EMG IZ estimation and nerve bundle entry point was 5mm (mean difference 2.8mm, p=0.767).
  
  
  CONCLUSIONS
  Preoperative surface electromyography of both gracilis muscles is a safe, precise and reliable method of assessing the location of the innervation zones of the gracilis muscles. The asymmetry of the IZ location in left and right muscles may be important in context of technical aspects of the graciloplasty procedure.
authors.affiliation: 3rd Department of General Surgery, Jagiellonian University Medical College, Krakow, Poland. Electronic address: m.romaniszyn@mp.pl.
authors.forename: Michal
authors.initials: M
authors.lastname: Romaniszyn
authors.affiliation: 3rd Department of General Surgery, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Walega
authors.affiliation: Department of Medical Education, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Nowakowski
authors.affiliation: 3rd Department of General Surgery, Jagiellonian University Medical College, Krakow, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Nowak
mesh_terms: D000328:Adult; D000368:Aged; D000066491:Clinical Decision-Making / Q000379:methods*; D004576:Electromyography / Q000379:methods* / Q000592:standards; D005260:Female; D000071976:Gracilis Muscle / Q000294:innervation* / Q000502:physiology* / Q000601:surgery; D006801:Humans; D007430:Intraoperative Care / Q000379:methods* / Q000592:standards; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology / Q000601:surgery
keywords: Dynamic graciloplasty; Electrode arrays; Gracilis muscle; Innervation; Surface electromyography