Australia’s novel surgical technique promises new life for tetraplegics
Select, formerly paralysed young adults in Australia are now able to perform everyday tasks independently thanks to a combination of nerve and tendon transfer surgeries. A nerve transfer is known to restore natural movement and fine motor control to the affected limb while a tendon transfer restores more power and heavy lifting ability. These allow for different styles of reconstruction and exhibit the innate strengths of both tendon and nerve transfers.
Surgeons recently completed 59 nerve transfers (27 limbs) in 16 participants in their mid-twenties with traumatic spinal cord injury to the neck, who were referred to Austin Health in Melbourne for restoration of function in the upper limb. The transfer involved taking working nerves to expendable muscles innervated above the spinal injury and attaching them to the nerves of paralysed muscles innervated below the injury to restore voluntary control and reanimate the paralysed muscle – for example, when a nerve to a shoulder muscle is attached to a muscle that straightens the elbow. Nerve transfers were also combined with tendon transfers to improve hand function in 10 of these participants (12 limbs) – a functioning muscle is re-sited to do the work of a paralysed muscle.
Participants then underwent independence assessments related to daily activities, such as hand opening ability and self-care, before and after surgery. At 24 months follow-up, significant improvements were noted in their ability to pick up and release several objects within a specified time frame. Pinch and grasp strength were also high enough to perform most activities of daily living.
Typically, nerve transfers have a shorter period of immobilisation after surgery (10 days in a sling vs. 6-12 weeks in a brace) and although three participants had four failed nerve transfers – a permanent decrease in sensation and a temporary decrease in wrist strength that resolved within the year following surgery – the overall surgery was well tolerated.
Dr. Natasha van Zyl, from Austin Health, believes that nerve transfer surgery offers an exciting new option for individuals with paralysis – the possibility of regaining arm/ hand functions to perform everyday tasks, which gives them greater independence and the ability to participate more easily in family and work life.
While it can take months after nerve transfer for nerve regrowth into the paralysed muscle to occur and full strength is achieved, Dr. Ida Fox from Washington University, US, thinks, “Nerve transfers are a cost-effective way to harness the body’s innate capability to restore movement in a paralysed limb. However, a detailed study of the reasons for nerve transfer failure is still required.”
