title: Implantation of cauda equina nerve roots through a biodegradable scaffold at the conus medullaris in rat.
abstract: BACKGROUND
  Traumatic injuries occurring at the conus medullaris of the spinal cord cause permanent damage both to the central nervous system and to the cauda equina nerve roots.
  
  
  OBJECTIVE
  This proof-of-concept study was to determine whether implanting the nerve roots into a biodegradable scaffold would improve regeneration after injury.
  
  
  METHODS
  All experimental works involving rats were performed according to the approved guidelines by the Mayo Clinic Institutional Animal Care and Use Committee. Surgical procedures were performed on 32 Sprague-Dawley rats. Four ventral cauda equina nerve roots were reimplanted either directly into the ventral cord stump or through a poly(lactic-co-glycolic acid) (PLGA) scaffold. These experimental groups were compared with a control group in which the nerves were inserted into a muscle fascia barrier that was placed between the spinal cord and the nerve roots. Animals were sacrificed at 4 weeks.
  
  
  RESULTS
  There was no difference in motor neuron counts in the spinal cord rostral to the injury in all treatment groups, implying equal potential for the regeneration into implanted nerve roots. One-way analysis of variance testing, with Tukey post hoc test, showed a statistically significant improvement in axon regeneration through the injury in the PLGA scaffold treatment group compared with the control (p<.05, scaffold n=11, control n=11).
  
  
  CONCLUSIONS
  This pilot study demonstrated that a PLGA scaffold improved regeneration of axons into peripheral nerve roots. However, the number of regenerating axons observed was limited and did not lead to functional recovery. Future experiments will employ a different scaffold material and possible growth factors or enzymes to increase axon populations.
authors: Mayo Graduate School, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Peter J
authors: PJ
authors: Grahn
authors: Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Sandeep
authors: S
authors: Vaishya
authors: Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Andrew M
authors: AM
authors: Knight
authors: Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Bingkun K
authors: BK
authors: Chen
authors: Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Ann M
authors: AM
authors: Schmeichel
authors: Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Bradford L
authors: BL
authors: Currier
authors: Department of Neurosurgery, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Robert J
authors: RJ
authors: Spinner
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA.
authors: Michael J
authors: MJ
authors: Yaszemski
authors: Mayo Graduate School, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA; Department of Neurology, Mayo Clinic, Rochester, 200 First Street SW, MN 55905, USA. Electronic address: windebank.anthony@mayo.edu.
authors: Anthony J
authors: AJ
authors: Windebank
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002420:Cauda Equina / Q000601:surgery*; D019344:Lactic Acid; D009416:Nerve Regeneration; D010865:Pilot Projects; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D012092:Replantation / Q000379:methods*; D013119:Spinal Cord Injuries / Q000601:surgery*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid
keywords: Cauda equina; Conus medullaris; Nerve root avulsion; Neuroregeneration; PLGA scaffold; Spinal cord injury