Intraoperative neuromonitoring (IONM) in thyroid surgery offers a valid aid to the operator in identifying the recurrent laryngeal nerve and preserving its function. Spinal accessory nerve palsy results in weakness or complete loss of strength in trapezius muscle, causing limitations in shoulder's movements, pain and a syndrome known as "shoulder syndrome".

The aim of our study is to assess whether the use of the IONM helps to reduce the incidence of transient and permanent paralysis of the spinal accessory nerve, compared to "de visu" identification by the surgeon alone. We enrolled patients with laterocervical lymph nodes metastasis for thyroid cancer treated with functional radical neck dissection. We report the results in terms of transitory and/or permanent palsies of the accessory spinal nerve between two group: group A treated with the "de visus" identification of the nerve and group B with the aid of IONM. In group A the integrity of the nerve was evaluated and preserved only with visual identification. For group B the identification and evaluation of the spinal accessory nerve was helped by IONM.

In our case series, the use of the IONM reduced the incidence of transient paralysis, and no permanent paralysis was recorded. IONM facilitates the safe identification of the spinal accessory nerve in a region crossed by several structures.

The early diagnosis performed with the aid of IONM and therefore the precocious start of rehabilitation treatments allow a high rate of recovery from the transitory palsy and lead to a reduction in healthcare costs.