Surgical techniques of nerve grafting (standard/vascularized/allograft)

Poly(D,L-Lactide-Co-Glycolide) Tubes With Multifilament Chitosan Yarn or Chitosan Sponge Core in Nerve Regeneration

PURPOSE

The influence of different kinds of nerve guidance conduits on regeneration of totally transected rat sciatic nerves through a 7-mm gap was examined.

MATERIALS AND METHODS

Five different types of conduits made of chitosan and poly(D,L-lactide-co-glycolide) (PLGA) were constructed and tested in vivo. We divided 50 animals into equal groups of 10, with a different type of conduit implanted in each group: chitosan sponge core with an average molecular mass of polymer (Mv) of 287 kDa with 7 channels in a PLGA sleeve, chitosan sponge core with an Mv of 423 kDa with 7 channels in a PLGA sleeve, chitosan sponge core (Mv, 423 kDa) with 13 channels in a PLGA sleeve, chitosan multifilament yarn in a PLGA sleeve, and a PLGA sleeve only. Seven weeks after the operation, we examined the distance covered by regenerating nerve fibers, growing of nerves into the conduit's core, and intensity and type of inflammatory reaction in the conduit, as well as autotomy behavior (reflecting neuropathic pain intensity) in the animals.

RESULTS

Two types of conduits were allowing nerve outgrowth through the gap with minor autotomy and minor inflammatory reactions. These were the conduits with chitosan multifilament yarn in a PLGA sleeve and the conduits with 13-channel microcrystalline chitosan sponge in a PLGA sleeve.

CONCLUSIONS

The type of chitosan used to build the nerve guidance conduit influences the intensity and character of inflammatory reaction present during nerve regeneration, which in turn affects the distance crossed by regenerating nerve fibers, growing of the nerve fibers into the conduit's core, and the intensity of autotomy in the animals.

Effect of upper extremity nerve damage on activity participation, pain, depression, and quality of life

PURPOSE

To explore the relationship between upper extremity nerve damage and activity participation, pain, depression, and perceived quality of life.

METHODS

A total of 49 patients with upper extremity nerve damage completed standardized measures of activity participation, pain, depression, and quality of life. We analyzed scores for all subjects and for 2 diagnostic groups: patients with compressive neuropathy and patients with nerve injury (laceration, tumor, and brachial plexus injury), and explored predictors of overall quality of life.

RESULTS

Participants had given up 21% of their previous daily activities; greater activity loss was reported in patients with nerve injury. Pain was moderate and 39% had signs of clinical depression. Physical and psychological quality of life ratings were below the norms. Activity loss was strongly associated with higher levels of depression and lower physical and psychological quality of life. Higher depression scores correlated strongly with lower overall quality of life. Greater pain correlated moderately with higher depression scores and weakly with quality of life; no statistical relationship was found between pain and physical quality of life. Activity participation and depression predicted 61% of the variance in overall quality of life in patients with nerve damage.

CONCLUSIONS

The results of this study suggest that hand surgeons and therapists caring for patients with nerve compression and nerve injury should discuss strategies to improve activity participation, and decrease pain and depression, to improve overall effect on quality of life throughout the recovery process. Depression screening and referral when indicated should be included in the overall treatment plan for patients with upper extremity nerve damage.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

Anatomic bases of vascularized elbow joint harvesting to achieve vascularized allograft

In order to later make precise the operative technique of free vascularized elbow allograft transfer, the anatomic conditions necessary for the success of such an operation are reviewed. The exact topography of the nutrient foramina of the humerus, radius, and ulna has been specified on 102 dry bones. The osseous resection at the recipient will have to be carried out on these aspects: nutrient foramina of the three bones of the elbow (at 9 cm from medial epicondyle for the humerus; at 8 cm for the two bones of forearm) in order to preserve diaphysary vascularization of the recipient. A study of arterial and venous vascularization carried out on 18 anatomic specimens showed that the osseous ends were irrigated by a periosteal arterial network and were drained in the centromedullary cavities. Systematization of the arteriovenous blood supply of the distal end of the humerus and proximal ends of the two forearm bones is proposed after dissection of 18 anatomic specimens. Arterial periosteal territories are defined. The importance of each peri articular arteriole is estimated according to the surface of its respective section. A radial, constant, and musculoperiosteal collateral artery from the brachial artery is described. It accounts for 12% (+/- 3%) of the total contribution. The recurrent radial artery is the most significant: 31% (+/- 9%) of the total contribution. The profunda brachii artery is negligible: 4% (+/- 2%) of the total contribution. As well for vascular as mechanical reasons, osteosynthesis will have to be carried out using screwed plates, the optimal location of which is specified according to the arterial periosteal cartography. Ulnar and radial nerves and, to a lesser extent, the median nerve can be harvested "en bloc" preserving their vascular supply in order to make vascularized grafts of them. Free vascularized elbow allograft transfer is technically possible, if one respects these anatomic bases.

Bridging the neural gap

A major limitation to overall success in peripheral nerve surgery is time for regeneration. Although one can help speed up the regenerative process to some extent, success is hindered by issues such as number of coaptation sites, supply of donor nerves, and the limitations of nerve substitutes. In the case of a large gap, a nerve graft is often used to fill in the deficit. Autogenous nerve grafts are in limited supply, with sural nerve grafts being the primary source. Alternatives to the standard treatment include vein grafts, synthetic nerve conduits, nerve transfers, and nerve transplantation. Schwann cell-lined nerve conduits and tissue-engineered substitutions are still in their infancy and have some limited clinical application.