Purpose: Spinal cord injury is definitive because the advancement of axon regeneration from cortical cells is blocked.

Material and methods: Research in the field began in 1980 with peripheral nerve grafts positioned between the stumps of the sectioned cord. Regenerated axons entered the grafts but were blocked when they reached the cord. We therefore developed the concept of connecting the fibres of the descending corticospinal cord directly to the nerves of selected muscles. Research was conducted over 22 years, first with rats then with monkeys. Mortality was high due to insufficient intensive care. For the surviving animals, muscles connected to the cord were trophic, moved, and responded to electrical stimulation of the nerve or the cord and presented histological features comparable to those of sutured peripheral nerves.

Results: After obtaining the approval of the national ethics commission, we performed the procedure in a young woman who was fully informed of the risks and volunteered for the operation. Before operating other patients, we decided to wait for the first clinical results. The operation consisted in connecting the corticospinal cord with the glutemus maximus and medius muscles and the quadriceps muscles (bilaterally). We expected to wait two years or more due to the distance between T10 and the innervated muscles. The patient moved and walked earlier than expected. At the present time, she is able to walk 10 to 15 minutes with a walking aid. In the pool, she is even able to climb a few steps. Her improvement continues.

Discussion: Since the innervation arises from the glutamatergic central motoneuron and the normal motor plaque is a cholinergic junction, research is continuing in rats to search for the genes which code for the receptors of the innervated muscle to learn whether the central motoneuron changes its transmittor or the muscle changes its receptors. Curarisation in these rats paralyses the normal muscles while the denervated muscles re-innervated with central motoneurons are not.

Conclusion: Apparently, the receptors of the motor plaque change. Further confirmation is needed.

Purpose: Carpal instability with scapho-lunate dissociation is still considered to result from the rupture of the so-called scapho-lunate (SL) ligament. Actually, this is not a ligament but a loose capsule allowing flexion of the scaphoid and lunate of very different magnitudes (92° versus 20°. Reconstruction of the SL “ligament” have often provided very disappointing results.

Material: Sections of the SL “ligament” on cadaveric specimens never produce SL dissociation. This dissociation can only occur if the scaphoid remains well-positioned in the articular facette of the radius. Rotory subluxation is possible only if the scapho-trapezotrapezoidal is cut, which allows posterior displacement of the scaphoid. This ligament is not described in anatomy textbooks because it is hidden by the sheath of the palmaris longus. Posterior luxation of the proximal pole of the scaphoid is required for dissociation from the semi-lunate.

Operative method: A reconstruction method for the volar scaphotrapezoid ligament using a band of the flexor carpi radialis tendon was developed on cadaveric specimens before application in 38 patients. The 7-cm band of the palmaris longus tendon, with an intact metatarsal attachment was passed through a tunnel drilled in the distal pole of the scaphoid. The band was then pulled dorsally (correctly positioning the scaphoid) and sutured to the dorsoulnar border of the radius.

Results: Carpal height was restored as was scaphoid-lunate mobility (flexion in radial deviation, extension in cubital deviation). The reduction was maintained at mid- and long-term with prevention of carpal collapse and arthritis. Among the 38 operated patients, 35 achieved full pain relief, three complained of moderate pain under stress. All patients were satisfied.

Discussion: Anatomic research and clinical results confirmed that the scaphotrapezoidal ligmament is the key element for dissociation and its repair.

Conclusion: This operation is currently the only procedure capable of providing easy and definitive repair of carpal instability with scapho-lunate dissociation.