The Artificial Nerve Graft: A Comparison of Blended Elastomer-Hydrogel with Polyglycolic Acid Conduits

Abstract

A study was undertaken to compare the regeneration of rat peroneal nerves across a 0.5-cm gap repaired with either a permanent, porous or a resorbable, non-porous artificial nerve graft. The resorbable, impermeable artificial nerve graft was a synthetic passive conduit made from polyglycolic acid (PGA). The permanent, porous artificial nerve graft conduit was manufactured from a hydrophilic elastomeric biopolymer (HEB), and four variations were tested. Qualitative histology on short-term animals revealed similar inflammatory reactions to HEB and PGA. Axonal regeneration was evaluated in longer-term animals after three, four, and six months by qualitative and quantitative histology. Qualitative histology on longer-term animals demonstrated both artificial nerve grafts to be anti-immunogenic. All PGA-artificial nerve graft repairs among three-, four-, and six-month rats contained myelinated axons, as did all HEB-1 repairs. However, three other HEB-graft varieties accounted for a 25 percent failed regeneration rate. Quantitative histologic comparison of repair-site cross-sections in viable PGA and HEB matched pairs demonstrated statistically equivalent myelinated axon counts but larger average myelinated fiber diameters in HEB repairs, with p = .001.

Combined polyglycolic acid tube and autografting versus autografting or polyglycolic acid tube alone. A comparative study of peripheral nerve regeneration in rats

“…Bridging the gap between the ends of a sectioned nerve with tubular conduits is an alternative technique with theoretical advantages such as better confinement of the regenerating axonal fibers, reduced inflammatory reaction and formation of cicatricial tissue at the repair site, proper guiding of fiber growth towards the distal end, prevention of donor-site associated sequelae, and shortened duration of surgery 2,3 .…”

Tubo de ácido poliglicólico e GM1 na regeneração de nervos periféricos

“…1 However, there are factors that lead us to pursue a new kind of conductor for axonal growth: 1. the removal of autologous grafting material always produce morbidity to the donor site; 2. large defects demand removal of extensive portions of autogenous tissue; 3. the use of artificial material saves the time for removing autologous tissue. 1,3 The interposition of tube conductors as a bridge between the stumps of a sectioned nerve has presented encouraging experimental and clinical results. For fixing small defects, where the distance between stumps is not big enough to cause problems to chemotaxis and chemotrophic attraction exerted by distal stump on axonal growth cone, the results are comparable to The mean value of the preoperative sciatic function rate for each group was: Group A (autografting) -8.…”

“…The sciatic nerve was used to provide a peripheral nerve injury model, since its functional repair pattern can be assessed 19 , and this is an important fact to compare the best technique when repairing neural tissue defects. The surgical technique employed for accessing sciatic nerve, autografting, and polyglycolic acid tubing is the same employed by several authors 3,9 , as well as the standard gap size used. 3 The technique for preparing histological sections using fixation with osmium tetroxide and toluidine blue stain is the one that best preserves myelin sheath, being widely employed in peripheral nerve studies.…”

“…those obtained with autografting. [1][2][3][4][5][6][7] The tubing technique also offers additional theoretical advantages over traditional grafting methods: it provides good coaptation of both stumps with less manipulation trauma; enables a better confinement of growing fibers inside the tube, isolating the repair site from surrounding inflammatory response; guides fiber growth towards distal stump, enabling local neurotrophic factors concentration; reduces neuroma formation and fibers escape to out of the conductor; enables the flow of regeneration enhancer substances. 5,6 Several materials have been employed for building tubes, which may be absorbable 8 or non-absorbable.…”

A utilização do tubo de ácido poliglicólico e FK506 na regeneração de nervos periféricos

“…It drives the axonal growth and links the ends of distal and proximal stumps, reducing tension at the suture line, a factor that could inhibit neural regeneration (1) . When using autografting, some factors must be considered: 1) it always produces morbidity of the donator area; 2) extensive neural tissue losses demand large amounts of autologous tissue, sometimes insufficient; 3) the use of synthetic materials reduces surgery time (2,3) . Studies on large neural tissue losses and the need of bridges connecting proximal and distal ends have been conducted during the second half of Nineteenth Century (4) .…”