title: Safe Zone for Neural Structures in Medial Displacement Calcaneal Osteotomy: A Cadaveric and Radiographic Investigation.
abstract: BACKGROUND
  We aimed to define reference lines on standard lateral ankle radiographs that could be used intraoperatively to minimize iatrogenic nerve injury risk in medial displacement calcaneal osteotomy.
  
  
  METHODS
  Forty cadaveric specimens were used. In 20 specimens, the sural, medial plantar (MP), and lateral plantar (LP) nerves were sutured to radiopaque wire, and a lateral ankle radiograph was obtained. On the radiograph, a line was drawn from the posterior superior apex of the calcaneal tuberosity to the origin of the plantar fascia and labeled as the "landmark line." A parallel line was drawn 2 mm posterior to the most posterior nerve, and the area between these lines was defined as the safe zone. In 20 additional specimens, an osteotomy was performed 1 cm anterior to the landmark line using a percutaneous or open technique. Dissection was performed to assess for laceration of the sural, MP, LP, medial calcaneal (MC), or lateral calcaneal (LC) nerves.
  
  
  RESULTS
  The safe zone was determined to be within the area 11.2 ± 2.7 mm anterior to the landmark line. After open osteotomy, lacerations were found in 3 of 10 MC nerves and 3 of 10 LC nerves. After percutaneous osteotomy, lacerations were found in 2 of 10 MC nerves and 1 of 10 LC nerves. No lacerations of the sural, MP, or LP nerves were found with either osteotomy.
  
  
  CONCLUSIONS
  The safe zone extended 11.2 ± 2.7 mm anterior to the described landmark line. The MC and LC nerves were always at risk during medial displacement calcaneal osteotomy.
  
  
  CONCLUSIONS
  Nerve injury to both major and minor sensory nerves is likely underrecognized as a source of morbidity after calcaneal osteotomy. The current study provides a ready intraoperative guideline for minimizing this risk.
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA Department of Orthopaedic Surgery, University of Michigan School of Medicine, Ann Arbor, Michigan, USA.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Talusan
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA.
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Cata
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Eric W
authors.initials: EW
authors.lastname: Tan
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA.
authors.forename: Brent G
authors.initials: BG
authors.lastname: Parks
authors.affiliation: Department of Orthopaedic Surgery, MedStar Union Memorial Hospital, Baltimore, MD, USA lyn.camire@medstar.net.
authors.forename: Gregory P
authors.initials: GP
authors.lastname: Guyton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000294:innervation* / Q000601:surgery*; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods*; D059348:Peripheral Nerve Injuries / Q000517:prevention & control*; D011859:Radiography; D013979:Tibial Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000293:injuries*
keywords: calcaneal osteotomy; percutaneous osteotomy; tibialis posterior tendinopathy