6. NERVE AUTOGRAFTING
Gold Standard in setting of a nerve gap
“ Expendable” donors:
• Sensory:
– MABC
– LABC
– Sural
Non‐immunogenic
• Sensory donors do not support motor regeneration
as well as mixed sensorimotor or pure motor nerves
• Motor:
-AIN
-PIN
-Nerve to gracilis
7. NERVE AUTOGRAFTING
the “down side”
• Harvest site morbidity (scarring,
neuroma formation, loss of donor
function)
(20-30% with painful donor site, cold
sensitivity, function alteration )
• Harvest time/cost
• Limited size and length available
8. Long Nerve grafts
• Long nerve grafts highly
successful in only one series
(biceps)
• Prognosis is nerve and site-
specific
• Axillary nerve graft results
mixed, generally 50% effective
• Reduced time to surgery,
shorter grafts associated with
improved outcomes
9. Vascularized nerve grafts
• Vascular pedicled ulnar nerve graft may offer some
advantages in poorly vascularized bed, but no
definitive data to support routine use
10. CONDUITS
• Often used for <3cm gaps in small-diameter sensory
nerves
• Potentially longer with biologic supplementation
• More questions about large mixed nerves
– Mackinnon, 2014 :In my practice, nerve conduits have
largely been replaced by acellularized nerve allografts
11. CONDUITS
the “down side”
• Use limited to small gaps;
– 34%-57% failure rate >5mm gaps
• cost
• lack laminin scaffolding
• lack Schwann Cells, which are crucial to axonal
regeneration
• Semi-rigid material cannot be used around joints
12. CONDUITS
the “down side”
• decreased concentration of neurotrophic factors
associated with larger diameter conduits
13. CONDUITS
the “down side”
• isograft is superior to nerve conduit even with minced nerve
• no significant difference in regeneration among motor,
sensory, or mixed minced nerves
15. NERVE ALLOGRAFTS
• taken from ABO blood‐type compatible individuals
– cadaveric
– living related donor
• small diameter nerves
(avoid necrosis of central aspect of nerve from lack of adequate
revascularization)
18. NERVE ALLOGRAFTS
• Mackinnon, 2014 :”should be reserved for unique
patients with irreparable peripheral nerve injuries,
which, left untreated, would lead to an essentially
nonfunctional limb”
19. ACELLULARIZED NERVE GRAFT
• Harvested from cadavers (Motor
nerves ,no branching)
• Decellularized with detergents
(Hudson et al.)
• Subjected to enzymatic
degradation of CSPGs with
chondroitinase (Neubauer et al.)
• Grafts sterilized with gamma
irradiation
• Stored at ‐80 C
26. ACELLULARIZED NERVE GRAFT
clinical studies
• RANGER® Study (ongoing)
• Meaningful Recovery (S3-S4 and M3-M5) in 87% of
nerve reconstructions
• No graft-related complications
27. ACELLULARIZED NERVE GRAFT
clinical studies
• MATCH® control arm of RANGER® study (ongoing)
• Outcomes are comparable to nerve autograft and
exceed those for nerve conduit in historical controls.
28. ACELLULARIZED NERVE GRAFT
skepticism
• McKinnon, 2014: “ contraindicated in motor nerve &
critical sensory nerve reconstruction ; autologous
repair with autograft or nerve transfer would always
be my reconstruction of choice in these defects”
• 2013 ASSH, San Francisco, CA: straw poll taken
during allograft nerve session found that the
overwhelming majority of surgeons would prefer
autograft to processed allograft if it were their own
mixed nerve being repaired.
32. • Pros
– Safe (as per studies)
– Single graft repair, no need for multiple cable graft orientation
– Multiple length and diameters (only up to 7cm length)
– Excellent handling properties
– Supporting clinical studies (ongoing)
– Time efficient
– ? Revision
• Cons
– Cost
– Must have a prediction of nerve and gap size
– Logistics ( scheduling, transfer and storage)
– Compromised host?/ previous infection?/ scarred bed?
cold preservation in University of Wisconsin solution antibiotics in solution
stored at 4 C for 7 days prior to implantation decreases immunogenicity
start FK506 three days pre‐operatively
Bassal laminae business. Chondroitin sulfate proteoglycans (CSPG deposits form a substantial barrier to regeneration