Treatment Injury

Radial nerve compression

Theatre positioning, radial nerve compression

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Event: Theatre positioning
Injury: Radial nerve compression

Key Points

  • Iatrogenic nerve injuries are often preventable and this is the responsibility of the whole theatre team
  • Preventive actions include appropriate positioning and padding of at-risk sites
  • Early diagnosis and treatment assists optimal recovery
  • Treatment includes pain management, physiotherapy and orthosis to prevent contracture
  • “The do’s and don’ts of arm positioning under general anaesthesia”, a New Zealand-specific educational poster, can be obtained from the New Zealand Society of Anaesthetists (nzsa@anaesthesia.org.nz) or from Professor Stringer as a PDF (mark.stringer@anatomy.otago.ac.nz).

Case Study

Jeannie, a 41-year-old secretary, had an injury to her radial nerve during gynaecology surgery. Other than menorrhagia and medicated hypertension, Jeannie was generally well.

Following an elective total laparoscopic hysterectomy the nurses noted that she had a reddened area on her upper arm. In the next few hours Jeannie’s hand became increasingly painful and she developed a wrist drop. Whilst Jeannie was able to oppose she was unable to extend her wrist or fingers and was scoring the pain 8 out of 10.

A radial nerve injury at the humerus level due to positioning during anaesthetic was diagnosed. Jeannie’s arm and hand were elevated on a pillow but remained slightly swollen. Following review by the house surgeon Jeannie was commenced on gabapentin 300mg three times daily, and physiotherapy and pain service reviews were requested.

The pain service review found that Jeannie was still complaining of intense pain in the radial distribution of her left hand. The hand was swollen and had a definite difference in sensation, as well as weakness of extension of her wrist and fingers. The pain specialist advised continuing with the gabapentin but also starting Jeannie on amitriptyline 10mg at night and a ketamine infusion. The physiotherapy review findings were very similar but did note some improvement since the medications had been started. Jeannie was shown some gentle finger and thumb exercises, which she found helpful.

In the next 24 hours there was some easing in the pain but Jeannie still had paraesthesiae and loss of sensation, particularly over the dorsum of the index finger and first web. Jeannie was discharged with an appointment to be seen at the outpatient pain service clinic a month later.

On review at the clinic the swelling had gone and the pain was only minor, although there was still some residual weakness and numbness. Jeannie was reassured that, although it
could take time, generally patients with this injury have a full recovery. The specialist also advised her to wean off the gabapentin. Jeannie’s treatment injury claim for radial nerve injury was accepted and ACC was able to assist with her ongoing treatment and weekly compensation.

Expert Commentary

Mark Stringer, Professor of Anatomy, MS FRCP FRCS
Jeannie’s otherwise successful surgery was complicated by an iatrogenic nerve injury (INI) secondary to malpositioning under general anaesthesia. The radial nerve is vulnerable to external compression where it spirals around the back of the humerus. As a result of the extrinsic compression of her radial nerve she developed a distressing and disabling wrist drop.

In a recent analysis of treatment injury claims accepted by ACC in 2009, the single most common cause of INI, accounting for more than 10% of claims (35 in total), was malpositioning under general anaesthesia. More than half of these malpositioning- related nerve injuries occurred in orthopaedics or general surgery but no surgical specialty was exempt. The ulnar nerve at the elbow and the brachial plexus are most frequently injured. The cause of the injury is typically (i) excessive stretch of the nerve, such as when the patient’s elbow is flexed more than 90o or their shoulder abducted by more than 90o for prolonged periods, or (ii) external compression of the nerve against a bone by a rigid structure such as an anaesthetic screen pole, an arm board or the edge of the operating table. Thus the ulnar nerve can be compressed against the medial epicondyle of the humerus, the common peroneal (fibular) nerve against the neck of the fibula or, as in this case, the radial nerve against the back of the humerus.

The unconscious patient is at risk of such injuries because they are unable to reposition the limb in response to neurological symptoms. The key is prevention, which is the joint responsibility of the whole theatre team. Being aware of which nerves are particularly at risk and in what circumstances is crucial. If a perioperative nerve injury occurs, successful treatment depends on prompt and accurate diagnosis and referral to an appropriate specialist, since delayed treatment jeopardises optimal recovery. In addition to expert pain management and physiotherapy, which Jeannie received, any areas of sensory impairment must be protected from injury and an orthosis, such as a wrist or foot splint, may need to be fitted to prevent a contracture.

A New Zealand-specific guideline based on the recommendations of the American Society of Anesthesiologists Task Force on Prevention of Perioperative Peripheral Neuropathies and, in consultation with local anaesthetists an educational poster, was developed in 2011 to provide guidelines on how to safely position the upper limbs of adults undergoing general anaesthesia. The poster entitled “The do’s and don’ts of arm positioning under general anaesthesia” is available from the New Zealand Society of Anaesthetists (nzsa@anaesthesia.org.nz) or a PDF can be obtained from the author.

William Taine, MBChB FRACS (Orthopaedics)
INIs may arise as direct or indirect injuries from surgery, retraction or injection, or be pressure injuries related to positioning.

Reviews have suggested elements of individual susceptibility associated with pre-existing diseases such as diabetes, tobacco use, and an anatomical predisposition such as arthritis, particularly with regard to the ulnar nerve at the elbow. The common pressure sites are well established and many injuries ought to be preventable.

In 2011 the American Society of Anesthesiologists published guidelines on INI prevention, which is considered the responsibility of the whole theatre team: anaesthetist, surgeon and nursing staff. Preventive actions include appropriate positioning and padding of at-risk sites, whilst early diagnosis with timely acknowledgement, advice and management as required will assist the patient in dealing with this type of injury.

The diagnosis of an INI can usually be made clinically based on symptoms and signs. In this case, sensory loss on the dorsum of the first web of the hand, with motor loss affecting wrist and finger extension, suggests radial nerve palsy. The most common site for this is the mid zone of the posterior arm, where the radial nerve is applied to the humerus deep to triceps. Extension of the limb in external rotation, particularly across an edge or ridge, is the most common cause.

Recovery from a peripheral INI is usually spontaneous and often complete; however, residual deficits may remain, particularly if pressure has been high and/or sustained. The outcome and time to recovery will depend on whether the lesion is functional (neuropraxia) or more severe (axonotmesis).

Management following the diagnosis of a pressure injury to a peripheral nerve is expectant. Neuralgic pain may occur during recovery and require active management. Also appropriate may be advice on the protection of insensate areas, physiotherapy to prevent stiffness, and splintage for function, particularly if there is a foot drop or wrist drop (as in this case).

Investigations such as nerve conduction studies or electromyography may confirm the diagnosis and assist in establishing a prognosis, or in monitoring recovery if the expected pattern of return of function does not occur.

References

• References/websites available upon request.

Claims information

Between 1 July 2005 and 12 January 2013 ACC received 1,888 claims relating to nerve injury associated with surgery, of which 1,548 were accepted. The most common reason for declining was that there was no injury, no causal link between the injury and treatment or that the injury was an ordinary consequence of the treatment.

About this case study

This case study is based on information amalgamated from a number of claims. The name given to the patient is therefore not a real one.

The case studies are produced by ACC’s Treatment Injury Centre, to provide health professionals with:

  • an overview of the factors leading to treatment injury
  • expert commentary on how similar injuries might be avoided in the future.

The case studies are not intended as a guide to treatment injury cover.

Send your feedback to: TI.info@acc.co.nz

How ACC can help your patients following treatment injury

Many patients may not require assistance following their treatment injury.

However, for those who need help and have an accepted ACC claim, a range of assistance is available, depending on the specific nature of the injury and the person’s circumstances. Help may include things like:

  • contributions towards treatment costs
  • weekly compensation for lost income (if there’s an inability to work because of the injury)
  • help at home, with things like housekeeping and childcare.

No help can be given until a claim is accepted, so it’s important to lodge a claim for a treatment injury as soon as possible after the incident, with relevant clinical information attached. This will ensure ACC is able to investigate, make a decision and, if covered, help your patient with their recovery.

Download

Download the case study here

March 2013 Newsletter

Published 12/03/2013

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