title: Anatomical considerations of fascial release in ulnar nerve transposition: a concept revisited.
abstract: OBJECTIVE
  Surgical transposition of the ulnar nerve to alleviate entrapment may cause otherwise normal structures to become new sources of nerve compression. Recurrent or persistent neuropathy after anterior transposition is commonly attributable to a new distal compression. The authors sought to clarify the anatomical relationship of the ulnar nerve to the common aponeurosis of the humeral head of the flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS) muscles following anterior transposition of the nerve.
  
  
  METHODS
  The intermuscular septa of the proximal forearm were explored in 26 fresh cadaveric specimens. The fibrous septa and common aponeurotic insertions of the flexor-pronator muscle mass were evaluated in relation to the ulnar nerve, with particular attention to the effect of transposition upon the nerve in this region.
  
  
  RESULTS
  An intermuscular aponeurosis associated with the FCU and FDS muscles was present in all specimens. Transposition consistently resulted in angulation of the nerve during elbow flexion when this fascial septum was not released. The proximal site at which the nerve began to traverse this fascial structure was found to be an average of 3.9 cm (SD 0.7 cm) from the medial epicondyle.
  
  
  CONCLUSIONS
  The common aponeurosis encountered between the FDS and FCU muscles represents a potential site of posttransposition entrapment, which may account for a subset of failed anterior transpositions. Exploration of this region with release of this structure is recommended to provide an unconstrained distal course for a transposed ulnar nerve.
authors.affiliation: Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona;
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mahan
authors.affiliation: Division of Neurological Surgery, University of Texas Medical Branch, Galveston, Texas;
authors.forename: Jaime
authors.initials: J
authors.lastname: Gasco
authors.affiliation: Tulsa Bone and Joint Associates, Tulsa, Oklahoma; and.
authors.forename: David B
authors.initials: DB
authors.lastname: Mokhtee
authors.affiliation: Division of Neurosurgery, University of California, San Diego, La Jolla, California.
authors.forename: Justin M
authors.initials: JM
authors.lastname: Brown
mesh_terms: D002102:Cadaver; D005205:Fascia / Q000473:pathology; D000071938:Fasciotomy; D005542:Forearm / Q000033:anatomy & histology / Q000294:innervation / Q000601:surgery; D006801:Humans; D058430:Humeral Head / Q000033:anatomy & histology / Q000473:pathology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000473:pathology; D009408:Nerve Compression Syndromes / Q000473:pathology / Q000601:surgery*; D019635:Neurosurgical Procedures / Q000379:methods*; D012086:Reoperation; D017211:Treatment Failure; D014459:Ulnar Nerve / Q000033:anatomy & histology / Q000473:pathology / Q000601:surgery*; D020424:Ulnar Neuropathies / Q000473:pathology / Q000601:surgery*
keywords: FCU = flexor carpi ulnaris; FDP = flexor digitorum profundus; FDS = flexor digitorum superficialis; anatomy; cadaver study; distal compression; peripheral nerve; reoperation; transposition; ulnar nerve