title: What Protects Certain Nerves from Stretch Injury?
abstract: The human tibial nerves is less prone to injury following joint arthroplasty compared with the peroneal nerves. Besides the anatomical distribution, other features may confer protection from stretch injury. We therefore examined the size, shape and connective tissue distribution for the two nerves. The tibial and peroneal nerves from each side of nine fresh human cadavers we reharvested mid-thigh. Proximal segments manually stretched 20%-25% were fixed in aldehyde, while the adjacent distal segments were fixed in their natural length. Paraffin sections stained by Masson's trichrome method for connective tissue were examined by light microscopy. Tibial nerves had 2X more fascicles compared with the peroneal, but the axonal content appeared similar. Analysis showed that neither nerve had a significant reduction in cross sectional area of the fascicles following stretch. However, fascicles from stretched tibial nerves become significantly more oval compared with those from unstretched controls and peroneal nerves. Tibial nerves had a greater proportion that was extrafascicular tissue (50-55%) compared with peroneal nerves (38%-42%). This epineurium was typically adipose tissue. Perineurial thickness in both nerves was directly related to fascicular size. Tibial nerves have several unique histological features associated with size, shape and tissue composition compared with the peroneal nerve. We suggest that more fascicles with their tightly bound perineurium and more robust epineurium afford protection against stretch injury. Mechanical studies should clarify how size and shape contribute to nerve protection and/or neurapraxia.
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Schraut
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Sharon
authors.initials: S
authors.lastname: Walton
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Jad
authors.initials: J
authors.lastname: Bou Monsef
authors.affiliation: Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois.
authors.forename: Susan
authors.initials: S
authors.lastname: Shott
authors.affiliation: Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Anthony
authors.initials: A
authors.lastname: Serici
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Lioubov
authors.initials: L
authors.lastname: Soulii
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Farid
authors.initials: F
authors.lastname: Amirouche
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Gonzalez
authors.affiliation: Department of Orthopaedic Surgery, University of Illinois Chicago, Chicago, Illinois.|Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, Illinois.
authors.forename: James M
authors.initials: JM
authors.lastname: Kerns
mesh_terms: D000369:Aged, 80 and over; D003238:Connective Tissue / Q000033:anatomy & histology* / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D059348:Peripheral Nerve Injuries / Q000517:prevention & control*; D010525:Peripheral Nerves / Q000033:anatomy & histology* / Q000502:physiology; D010543:Peroneal Nerve / Q000033:anatomy & histology* / Q000293:injuries / Q000502:physiology; D013979:Tibial Nerve / Q000033:anatomy & histology* / Q000293:injuries / Q000502:physiology
keywords: cadaver study; histology; joint arthroplasty; nerve; stretch