In this article, Professor Patrick Broe, retired Consultant Surgeon and Clinical Director at the RCSI Hospital Group, highlights the causes of surgical injury to the spinal accessory nerve, which is frequently not recognised, and discusses the risks with performing surgical cervical lymph node biopsy.

Damage to the spinal accessory nerve has life-long implications for the patient and can be associated with significant litigation costs. The State Claims Agency received five claims in the last six years relating to spinal accessory nerve injury, two of which were finalised resulting in paid damages of €261,308.

Table 1: NIMS (National Incident Management System) data for spinal accessory nerve injury claims*

Clinical vignette

A 17-year-old female was referred to a surgical clinic by her GP with a four-month history of persistent cervical lymphadenopathy in the posterior neck, with no other symptoms. An excision biopsy of one of the nodes was advised and performed two weeks later under general anaesthetic. Histology showed a benign, “reactive” node and the reporting pathologist raised the possibility of Toxoplasmosis. Only then did it emerge that the family owned a cat.

Eighteen months later the patient was referred by her GP to a neurologist with a four-month history of weakness in her left arm and discomfort in her left shoulder. The neurologist made a diagnosis of left spinal accessory nerve injury, due to the previous lymph node biopsy. Nerve conduction studies confirmed complete motor conduction block at the level of the surgical scar in her neck. Repair of the nerve was performed by a plastic surgeon, using a supraclavicular nerve graft. Nerve conduction studies, one year later, showed minimal partial re-innervation and no further return of muscle function could be expected.

Surgical injury of the spinal accessory nerve

The commonest cause of injury to the spinal accessory nerve is iatrogenic, occurring as it does during surgical excision biopsy of cervical lymph nodes in the posterior triangle of the neck. A 3-8% incidence rate following cervical node biopsy is recorded. The nerve is extremely vulnerable because it is covered only by the skin and subcutaneous fascia in the posterior triangle of the neck. The vast majority of surgeons are unaware that they have injured or transected the nerve during the procedure. Numerous case reports and small series question the diagnostic value of cervical node biopsy because the pathology report is almost always benign/ reactive.

Recognition of the injury within six months of the node biopsy operation allows for timely re-exploration of the wound and either primary repair of the nerve or interposition nerve grafting. The trapezius muscle then has a good chance of recovery. Patients identified later, with a significant muscular deficit, are unlikely
to benefit from repair.

Management of cervical lymphadenopathy

Cervical lymphadenopathy is common in children and young adults. In most patients, it is benign and self-limiting and, in most instances, the pathology is benign/reactive.

Following an appropriate history and physical examination, and provided there are no alarming features (large node size, hard consistency, associated skin induration) a three to fourweek period of observation is appropriate, followed by a review. Serology tests for EBV, CMV and Toxoplasmosis are worthwhile if there’s a history of immunocompromise, or if there’s a cat in the household. In the knowledge that the vast majority of cases are benign and self-limiting, there is no indication to proceed to biopsy early in the clinical course.

There may be increasing anxiety in the patient, or their parents, with the persistence of the lymphadenopathy, particularly if there has been a previous history of lymphoma or other cancers in the family. To allay anxiety, and in some other instances, fine needle aspiration (FNA) of the node can be performed, and where the node(s) are larger, core biopsy could be considered. Open biopsy under local or general anaesthetic should be a last resort in cases where the FNA or core biopsy results are inconclusive.

If open lymph node biopsy is necessary, the procedure, even though considered minor and routine, should be performed by an experienced surgeon who is aware of the potential for injury to surrounding structures, such as the spinal accessory nerve in the case of posterior triangle node biopsy. If a trainee or more junior surgeon performs the procedure, it must be under supervision of a senior, experienced colleague. Damage to the spinal accessory nerve has life-long implications for the patient, which is a high price to pay to confirm what is, in most cases, a benign process.