Evidence-based surgical management of substernal goiter.

BACKGROUND: A number of reports have been published concerning the surgical treatment of substernal goiters; however, there is yet to be a comprehensive review of this body of literature using evidence-based methodology.
METHODS: This article is a systematic review of the literature using evidence-based criteria and a review of unpublished data from our institution.
RESULTS: Issue 1. Limited level III/IV data suggest that the incidence of cancer in substernal goiters is not higher than the incidence of cancer in cervical goiters. Risk factors for malignancy in substernal goiters may include a family history of thyroid pathology, a history of cervical radiation therapy, recurrent goiter, and the presence of cervical adenopathy (grade C recommendation). Issue 2. Prospective level V data suggest that, for most patients, expert endocrine surgeons utilize an extracervical approach approximately 2% of the time to remove a substernal goiter safely; a sternotomy or thoracotomy appears more likely in cases of a primary substernal goiter or a mass larger than the thoracic inlet (no recommendation). Issue 3. There may be a higher rate of permanent hypoparathyroidism and unintentional permanent recurrent laryngeal nerve injury when total thyroidectomy is performed for removal of a substernal goiter than for removal of a cervical goiter alone (grade C recommendation). Injury of the external branch of the superior laryngeal nerve was not specifically addressed and is almost certainly underreported. Issue 4. The presence of a substernal goiter, especially being present more than 5 years and causing significant tracheal compression, is likely a risk factor for tracheomalacia and tracheostomy (grade C recommendation). Tracheomalacia with substernal goiter is an infrequent occurrence, and many cases of tracheomalacia can be managed without tracheostomy (no recommendation). Issue 5. Prospective level V data suggest that about 5% to 10% of operations for substernal goiters are performed because of recurrent or persistent disease, although retrospective level V data report an even higher rate, up to 37%. The most common initial operations with recurrence or persistence appear to be subtotal or hemithyroidectomy (no recommendation).
CONCLUSION: Evidence-based recommendations provide reliable information regarding the pathologic findings and operative management of substernal goiters in expert hands.