Surgery of Carotid Body Tumors
Trends in Neurovascular Complications of Surgical Management for Carotid Body and Cervical Paragangliomas: A Fifty Year Experience with 153 Tumors, Hallett, Journal of Vascular Surgery 7:284 (1988)
Most cervical paragangliomas adhere to or surround the carotid arteries and local cranial nerves. Because these tumors most commonly originate from the carotid body, they are usually referred to as carotid body tumors or paragangliomas.
In this article, the authors reviewed 153 cervical paragangliomas treated at the Mayo Clinic during a 50-year period (1935-1985). These tumors were staged according to the classification of Shamblin. Shamblin classified the tumors based on the difficulty of surgical resection. Group 1 tumors are localized between the external and internal at the carotid bifurcation. These tumors are localized and easily resected. Group 2 tumors are adherent or partially surrounding vessels. Group 3 paragangliomas intimately surround or encase the vessels. This articles contains drawings of these three groups. We examined the factors that may possibly increase the risk of stroke, cranial nerve injury or death. A preoperative cranial nerve deficit (7, 9, 10, and 11) was noted in 10%. Most tumors (70%) were in Group 2 or 3. In Shamblin Group 2 or 3, the carotid vessels and cranial nerves were at increased risk for injury during resection. Post-operative cranial nerve dysfunction remained essentially unchanged over fifty years and affected approximately 40% of patients.
In the period 1976 to 1986, there were 37 tumors examined and post-operative cranial nerve dysfunction occurred in 15 (40%). The most commonly involved nerves were the hypoglossal (12), superior laryngeal (10), vagus (10), mandibular branch of the facial nerve (7), the pharyngeal branch of the vagus nerve (10), glossopharyngeal (9), the spinal accessory, and the sympathetic chain (Horner’s Syndrome). Common complaints were dysphagia (9 and 10), hoarse voice (10), difficulty chewing food (12), and choking easily on food (9 and the pharyngeal branch of 10). Cranial nerve injury was temporary in 52% but permanent in 48%. The median tumor size among patients with post-operative complications was significantly larger than those without complications (median size 17 cm3 versus 7 cm3).
The authors recommend complete surgical resection of all cervical paragangliomas in good risk patients. Local recurrence affected 5% of patients, and metastatic disease was found in 1.7%. Although carotid body tumors may grow slowly and be asymptomatic for many years, they eventually cause symptoms in nearly 75% of patients. Large tumors are certainly more difficult to resect and they found in this study that they were associated with a significantly higher rate of neurovascular injury.
The authors conclude that cranial nerve deficits can be reduced. First, only 10% of patients have a preoperative deficit, and generally the only nerve that occasionally requires resection is the vagus nerve when a tumor involves it. Second, most cranial nerve deficits after operation are because of a poor understanding of their location in relation to the tumor, adherence or incorporation of the nerves in the tumor surface, inadequate exposure, and lack of commitment to a careful nerve preserving dissection.