A technique for creating critical-size defects in the metatarsus of sheep for use in investigation of healing of long-bone defects.

Objective: To develop a technique for use in investigation of healing of long-bone defects by creation of a critical-size defect in the left metarsal III and IV bone (metatarsus) of sheep.

Animals: 18 healthy adult sheep.

Procedure: Sheep were allocated to 4 groups (3, 3, 5, and 7 sheep in groups 1 to 4, respectively).

[Post-traumatic reconnection of the cervical spinal cord with skeletal striated muscles. Study in adult rats and marmosets].

In an attempt at repairing the injured spinal cord of adult mammals (rat, dog and marmoset) and its damaged muscular connections, we are currently using: 1) peripheral nerve autografts (PNG), containing Schwann cells, to trigger and direct axonal regrowth from host and/or transplanted motoneurons towards denervated muscular targets; 2) foetal spinal cord transplants to replace lost neurons. In adult rats and marmosets, a PNG bridge was used to joint the injured cervical spinal cord to a denervated skeletal muscle (longissimus atlantis [rat] or biceps brachii [rat and marmoset]). The spinal lesion was obtained by the implantation procedure of the PNG.

Motoneurons of the injured spinal cord of the adult dog can grow lengthy axons into an autologous peripheral nerve graft. A retrograde axonal tracing study.

To our knowledge, the capacity of injured spinal neurons to regenerate axons into peripheral nerve autografts has not yet been documented with axonal tracing methods in large adult mammals such as dogs. In the present study, one end of an autologous peripheral nerve graft (PNG), 10-15 cm long, was introduced dorsally into the lumbar (L4) spinal cord of six adult beagle dogs, thus producing a small focal lesion. The other end of the PNG was driven outside the spinal cord, then crushed and tied to nearby peripheral tissue with non-absorbable suture.