Selective denervation (SD) is an operation that has been used for neck dystonia (spasmodic torticollis) for a number of years. It is a surgical operation to cut the nerves controlling the overactive muscles that are causing the symptoms of dystonia. The aim of the operation is to introduce a permanent paralysis to the muscles causing the problems. This information is provided by Mr James Palmer, Consultant Neurosurgeon and Medical Director at the Derriford Hospital in Plymouth.

When is denervation considered?

People normally consider SD when botulinum toxin treatment has been tried and has failed or is starting to fail. It is important to see patients early after the failure of previous treatments - not years later. If patients are referred early, denervation offers a chance of providing a permanent fix for their neck dystonia. However, patients who are referred  after many years often don’t do well: the constant twisting of torticollis will have caused destruction of the joints in the neck. However, even in these cases the procedure can often reduce pain and improve head position although it is difficult to return the neck to having a good range of movement once the bones have been damaged.

When is denervation not appropriate?

If the neck dystonia involves too many muscle groups, SD may not be feasible because it would involve trying to cut too many nerves. Some nerve pathways always need to be maintained to preserve neck movement. Some types of neck dystonia are easier to treat than others. The best results are usually obtained in cases of a rotation or twist of the neck. The hardest cases to treat are cases where the neck is pulled up and backwards because there are so many muscles involved. This wouldn’t necessarily preclude the operation taking place, but the chances of success are less.

What are the benefits of this surgery?

For the right patient, there is a very reasonable chance (maybe 40%) of eradicating the effects of dystonia. Even in other cases there should be marked – and permanent - improvement in position and body image which for me is one of the most rewarding reasons for carrying out this procedure. Following surgery, a neurophysiologist or a physiotherapist is on hand to teach the patient exercises to build up the strength of their neck muscles. This is important.

What are the disadvantages?

In a few cases there is a risk of incurring temporary swallowing problems. In extremely rare cases this can become permanent. As in the case of botulinum toxin, swallowing problems may follow injections but the symptoms do ease. Surgery can certainly leave you with several numb patches at the back of the head because some of the sensation nerves have to be removed. However it is an operation in which the muscles usually heal very well and there aren’t many risks involved in this type of surgery.

Is it difficult to get funding for this type of surgery?

Because it’s approved by the National Institute for Clinical Excellence (NICE) and has a tariff, our hospital is quite happy to operate and provide treatment. It’s free for every member of the NHS. I’ve not had a problem getting funding so far.

Why are there so few neurosurgeons performing this type of operation?

More are not needed! When I first started I worked out there were about 400 patients in the UK which might benefit from this operation. One surgeon can probably treat all 400 in their career. The technique is very different from other types of neurosurgery. I’m sure as I get older I will need to make sure another surgeon is trained to take over. You only need one or two surgeons in the UK to do this procedure as it needs particular expertise.


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