Results of intraoperative neuromonitoring in thyroid surgery and preoperative vocal cord paralysis.

BACKGROUND: Systematic studies of intermittent intraoperative neuromonitoring (IONM) have shown that IONM enhances recurrent laryngeal nerve (RLN) identification via functional assessment, but does not significantly reduce rates of vocal cord (VC) paralysis (VCP). The reliability of functional nerve assessment depends on the preoperative integrity of VC mobility. The present study was therefore performed to analyze the validity of IONM in patients with pre-existing VC paralysis. METHODS: Of 8,128 patients, 285 (3.5 %) with preoperative VCP underwent thyroid surgery using standardized IONM of the RLN and vagus nerves (VNs). VC function was assessed by pre- and postoperative direct videolaryngoscopy. Quantitative parameters of IONM in patients with VCP were compared with IONM in patients with intact VC function. Clinical symptoms and surgical outcomes of patients with pre-existing VCP were analyzed. RESULTS: A total of 244 patients revealed negative, and 41 revealed positive IONM on the side of the VCP. VCP with positive IONM revealed significantly lower amplitudes of VN and RLN than intact VN (p = 0.010) and RLN (p = 0.011). Symptoms of patients with VCP included hoarseness (25 %), dyspnea (29 %), stridor (13 %), and dysphagia (13 %); 13 % were asymptomatic. New VCP occurred in five patients, ten needed tracheostomy for various reasons, and one patient died. CONCLUSIONS: Patients with pre-existing VCP revealed significantly reduced amplitude of ipsilateral VN and RLN, indicating retained nerve conductivity despite VC immobility. Preoperative laryngoscopy is therefore indispensable for reliable IONM and risk assessment, even in patients without voice abnormalities.

Hypercalcitoninemia in thyroid conditions other than medullary thyroid carcinoma: a comparative analysis of calcium and pentagastrin stimulation of serum calcitonin.

PURPOSE: Calcitonin screening aims at uncovering occult medullary thyroid cancer (MTC) in patients with nodular thyroid disease. Elevated basal calcitonin serum levels call for calcitonin stimulation, the level of which may direct the extent of surgery. Because pentagastrin has become restricted, calcium has increasingly been used instead for stimulation. This study identified a new spectrum of patients demonstrating a false-positive hypercalcitoninemia in the absence of C-cell disease, carrying multinodular goiter (MNG), thyroiditis, and non-MTC thyroid malignancy, and endeavored to explore the feasibility of extrapolating pentagastrin-stimulated to calcium-stimulated calcitonin thresholds. METHODS: Altogether, 43 (9.5 %) of 455 patients with nodular thyroid disease revealed increased basal calcitonin serum levels between 2005 and 2012, for which they underwent intravenous stimulation with pentagastrin (31 patients) or calcium gluconate (12 patients) before and after primary thyroidectomy. RESULTS: Stimulation with calcium gluconate resulted in significantly higher and more variable preoperative calcitonin serum levels after 2 (241.2 vs. 104.9 pg/mL; P = 0.018) and 5 min (240.6 vs. 87.4 pg/mL; P = 0.007) than stimulation with pentagastrin. Stimulation with calcium gluconate produced 10-fold (nodular goiter), 15-fold (thyroiditis), and 21-fold (thyroid neoplasia other than MTC) calcitonin increases over baseline, as opposed to 5-fold, 10-fold, and 8-fold increases after stimulation with pentagastrin. None of the 43 patients, all of whom reverted to undetectable calcitonin serum levels after thyroidectomy, had immunohistochemical evidence of C-cell disease. Subgroup analyses according to gender and thyroid disease, being limited by the low number of patients in each subgroup, did not yield significant differences. CONCLUSIONS: Calcium stimulation yields significantly greater calcitonin levels than pentagastrin stimulation, precluding generalization of pentagastrin-stimulated to calcium-stimulated calcitonin thresholds. After calcium stimulation, false-positive findings appear to be more common in patients of female gender and patients with thyroiditis and thyroid neoplasia other than MTC, potentially effecting surgical overtreatment.

Management of lymph fistulas in thyroid surgery.

PURPOSE: Postoperative lymphatic leakage following thyroid surgery represents a management problem with considerate potential morbidity, psychological, and economical impact. Conservative and surgical management strategies for high- and low-output lymph fistulas are inconsistent. Reliable criteria to predict outcome of conservative versus surgical treatment in clinically evident lymph fistula are lacking. MATERIAL AND METHODS: A retrospective single-center chart review of consecutively quality-control-documented thyroid surgeries from January 1998 to December 2009 was performed to identify reported postoperative lymph fistulas. Documentation of surgical procedures, drainage, medical, and nutritional management was analyzed to identify risk factors for occurrence and criteria for management of evident lymph fistulas. RESULTS: There were 29 patients identified with postoperative clinical evidence of lymph fistulas following thyroid surgery; incidence was 0.5%. Indication to surgery comprised benign nodular goiter, recurrent nodular goiter, and thyroid carcinoma or local and lymphonodal carcinoma recurrences. There were 12 (41%) primary and 17 (59%) redo surgeries performed. Surgical procedures performed included thyroidectomy, completion thyroidectomy, and primary and redo central and lateral systematic microdissection of lymphatic compartments. All patients were initially submitted to fasting diet and medical treatment, successfully in 19 (66%), whereas ten (34%) patients underwent surgical intervention for fistula closure after failure of conservative treatment. Complications were one wound infection and fistula recurrence in five (26%) patients in the conservative group and two (20%) in the surgical group. Hospital stay was exceedingly prolonged in both groups with a median of 21 and 11 versus 6 days in patients with regular postoperative course following thyroid surgery. CONCLUSIONS: Data of this series support definition of the two categories of high- and low-output fistulas according to drainage collection with >300 versus <200 ml/day. Fasting in low-output fistula facilitates conservative treatment with closed drainage, whereas in high-output fistulas surgical intervention should be sought. Attendant criteria for treatment stratification are equally important, like patient's compliance, nutritional, and general health status as well as evidence for wound infection. Surgical closure of lymph fistula may be demanding when identification of the secreting fistula is limited and even muscle flap fortification may fail. Ultimately, in unsuccessfully reoperated fistula recurrences, open drainage may become necessary. Lymph fistulas cause significantly prolonged hospital stay, possible critical clinical decay, and unfavorable cosmetic and oncologic outcome while the superior management remains to be defined.