A new surgical technique has enabled 13 people with quadriplegia to feed, drink, brush their teeth and write, restoring the functionality of paralyzed muscles. The study, published in The Lancet, brings together the largest case study on upper-limb nerve transplantation ever collected so far.
According to the WHO, up to 500,000 people suffer spinal cord injuries each year, more than half of which become a quadriplegic. For people with quadriplegia, the recovery of hand function is the most important goal. Recovering arm and hand functions for daily activities can give these patients greater independence and the ability to participate more easily in family and work life.
A recent study published in The Lancet reports on the results of the Australian team led by Dr. Natasha van Zyl in the field of tendon and nerve transplantation. Traditionally, the function of the upper limb is restored by tendon transfer. Healthy muscles are surgically repositioned to perform the work of the paralyzed muscles. Nerve transplants, on the other hand, allow the function of the paralyzed muscle to be recovered. This method consists of connecting motor nerves from healthy muscles located upstream of the lesion to nerves from paralyzed muscles located below the level of the lesion. This technique has several advantages, including the possibility of recovering the function of several muscles at the same time and a shorter period of post-surgery immobilization.
In the past, individual clinical cases and small retrospective studies have already shown that nerve transplant surgery is feasible and safe in people with quadriplegia. But this is the first prospective study that measures results in a standardized way and presents combinations of nerve transplantation and tendon transfer surgery. The study shows the progress of patients 24 months after surgery in terms of muscle strength (triceps) and dexterity and grip (flexors and extensors of the fingers).
In total, the study recruited 16 young adults (average age 27 years) with recent traumatic lesions of the spinal cord at the cervical level (C5-C7). Participants underwent single or multiple nerve transplants in one or both upper limbs to restore elbow extension, grasping, pinching and hand opening. In total, 59 nerve transfers were completed in 16 participants (13 men and three women, 27 limbs). In 10 participants (12 limbs), nerve transfers were combined with tendon transfers to improve hand function.
Participants completed assessments of their level of independence in relation to daily life activities before surgery, one year after surgery and again after two years. Two participants were lost, and there was a death (not related to surgery).
At 24 months, significant improvements were observed in the ability of the hands to collect and release different objects. Before surgery, none of the participants were able to score on the grip force or pinch force tests, but 2 years later the grip and pinch force were high enough to perform most of the activities of daily life.
Despite these results, the technique still has some limitations. For best results, transplants should ideally be performed within 6-12 months of the injury. In addition, it may take months for nerve regeneration in the paralyzed muscles and to achieve the restoration of a new movement, and years until full strength is restored.
Stem cells and neuroprostheses may change the landscape of regenerative medicine in the future. For now, nerve transplants are a convenient way to take advantage of the body's innate ability to restore movement in a paralyzed limb. It is a field of medicine that still requires a lot of research, but the results so far are encouraging.
Last month, in Turin, Italy this innovative and revolutionary technique was performed for the first time in the country. The patient - a 52-year-old former pastry chef - had suffered a complete cervical spinal cord injury following a car accident. The patient was driving his car one evening back from work during a bad storm in early 2019, when he lost control of his car, going off the road. The trauma caused by such events, in addition to the complete deficit of the lower limbs, can include the inability to open and close the fingers, removing the capacity to grab objects or to provide for the patient’s autonomous personal care. The surgery was performed six months after the trauma on both upper limbs. The surgical procedure lasted about 3 and a half hours per limb, during which still functioning nerves were connected to deficient nerves in an attempt to “reinnerve” the hands’ muscles. There were no periprocedural complications. The recovery of motor function takes many months and will be facilitated by modern physiotherapy treatments to preserve and promote the motility of the areas concerned.