title: Safe zone for the superior gluteal nerve in the transgluteal approach to the dysplastic hip: intraoperative evaluation using a nerve stimulator.
abstract: BACKGROUND
  The superior gluteal nerve can be damaged during the transgluteal approach to the hip in total hip arthroplasty.
  
  
  METHODS
  We studied 30 patients with hip dysplasia who underwent total hip arthroplasty through the transgluteal approach. The course of the inferior branch of the superior gluteal nerve was identified using a nerve stimulator. The distance between the nerve and the tip of the greater trochanter was measured.
  
  
  RESULTS
  The mean distance was 37 (25-45) mm at the anterior third, 40 (30-50) mm at the middle third, and 44 (35-55) mm at the posterior third of the gluteus medius. The distance was influenced by the severity of hip dysplasia and decreased as the degree of hip dysplasia became more severe.
  
  
  CONCLUSIONS
  A 3-cm safe zone is appropriate in most dysplastic hips. In severely dysplastic hips, however, the superior gluteal nerve occasionally coursed within 3 cm of the tip of the greater trochanter. In such hips, a nerve stimulator can be used to identify the nerve.
authors.affiliation: Department of Orthopaedic Surgery, Kochi Medical School, Kochi University. Nankoku, 783-8505. Japan. ikeuchim@med.kochi-u.ac.jp
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ikeuchi
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Kawakami
authors.forename: Norio
authors.initials: N
authors.lastname: Yamanaka
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Okanoue
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Tani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D002081:Buttocks / Q000294:innervation*; D004558:Electric Stimulation; D005260:Female; D006617:Hip Dislocation / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000517:prevention & control; D011859:Radiography; D012449:Safety