The functional impact on voice of sternothyroid muscle division during thyroidectomy.
ABSTRACT Post-thyroidectomy voice dysfunction may occur in the absence of laryngeal nerve injury. Strap muscle division has been hypothesized as one potential contributor to dysphonia.
Vocal-function data, prospectively recorded before and after thyroidectomy from two high-volume referral institutions, were utilized. Patient-reported symptoms, laryngoscopic, acoustic, and aerodynamic parameters were recorded at 2 weeks and 3 months postoperatively. Patients with and without sternothyroid muscle division during surgery were compared for voice changes. Patients with laryngeal nerve injury, sternohyoid muscle division, arytenoid subluxation or no early postoperative follow-up evaluation were excluded. Differences between study groups and outcomes were compared using t-tests and rank-sum tests as appropriate.
Of 84 patients included, 45 had sternothyroid division. Distribution of age, gender, extent of thyroidectomy, specimen size, and laryngeal nerve identification rates did not differ significantly between groups. There was a significant predilection for or against sternothyroid muscle division according to medical center. No significant difference in reported voice symptoms was observed between groups 2 weeks or 3 months after thyroidectomy. Likewise, acoustic and aerodynamic parameters did not differ significantly between groups at these postoperative study time points.
Sternothyroid muscle division is occasionally employed during thyroidectomy to gain superior pedicle exposure. Division of this muscle does not appear to be associated with adverse functional voice outcome, and should be utilized at surgeon discretion during thyroidectomy.
Article: Strap muscle neurovascular supply.[show abstract] [hide abstract]
ABSTRACT: Knowledge and preservation of the neurovascular supply to strap muscles, such as the sternohyoid (SH) muscle, used in laryngotracheal reconstruction are important in preventing loss of tissue and bulk from ischemia and/or denervation. Arteriovenous and neural supply variations to the strap muscles were examined in cadaver specimens. Strap muscle neurovascular supply was studied in 16 cadavers, including one transparent corrosion cast specimen with injected vessels. For the upper SH and upper belly of the omohyoid (OMO), the arterial supply consistently arose from a branch of the superior thyroid artery (STA) most commonly terminating at the cricothyroid membrane. The inferior SH was supplied by the inferior thyroid artery. The ansa cervicalis innervated the SH inferiorly with a branch below the loop. Each arterial branch to the muscles had an accompanying venous tributary. The corrosion cast specimen demonstrated that the arterial lumen diameters were almost threefold larger in branches entering the upper SH, compared with the lower SH or OMO. Small intramuscular arteries without axial supply were found within the middle third of the upper SH, the lower SH, and the upper OMO. It is possible to preserve neurovascular integrity in an inferiorly based SH flap. The superior and medial borders are released, with dissection of vascular supply laterally and deep to the muscle, and preservation of the inferior terminal ansa branch.The Laryngoscope 08/1998; 108(7):973-6. · 1.98 Impact Factor
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ABSTRACT: Vocal dysfunction in patients with thyroid pathology has been poorly documented, and dysfunction after thyroid surgery is generally reported in terms of recurrent laryngeal nerve or external laryngeal nerve palsy. But voice dysfunction is more complex than simply nerve integrity. The present study reports the incidence of dysphonia in patients presenting for thyroid surgery, and relates postoperative changes in vocal function to recurrent and external laryngeal nerve function, and the surgical handling of the strap muscles. Fifty patients were assessed by Visipitch before and after thyroidectomy. Following surgery the patients filled out a questionnaire. Overall 26 of 44 patients had no subjective postoperative voice change, while 10 reported subjective deterioration and eight reported subjective improvement in voicing. Postoperative objective assessment of these patients found that 17 were the same, eight refused to come for testing because they felt their voice had not changed, 13 were better and six were worse. Following surgery two patients (4.5%) had temporary recurrent laryngeal nerve palsies (2.5% of nerves at risk), and four patients (10%) suffered external laryngeal nerve palsies. Division of strap muscles was not detrimental to voicing. Six patients were lost to follow-up. Fifteen patients (34%) presented with vocal abnormalities, six (40%) of whom improved postoperatively. Patients may have voicing abnormalities before thyroid surgery is performed. Surgery may improve or worsen the voice irrespective of the pre-operative voice status.Australian and New Zealand Journal of Surgery 04/2000; 70(3):179-83.
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ABSTRACT: Injury of the inferior laryngeal nerve is not the only cause of voice alteration after thyroidectomy; many patients notice minimal changes immediately after operation, without evidence of inferior laryngeal nerve damage. We hypothesized that there may be other causes for voice modification, such as injuries of the superior laryngeal nerve, prethyroid strap muscles, and cricothyroid muscles. We describe voice changes after total thyroidectomy, without inferior laryngeal nerve injury, using a computer program to objectively compare different patterns of voice. Forty-six consecutive patients who underwent total thyroidectomy were studied between March 1997 and December 1999. Acoustic voice analysis was performed preoperatively and at the second, fourth, and sixth postoperative months using a microphone adapted to a personal computer. Parameters measured were intensity of the voice (Shimmer) and fundamental frequency (Fo). No complications occurred during operation or in the postoperative period. Voice fatigue during phonation was the most common symptom after thyroidectomy. Forty patients (87%) stated that their voices had changed since the operation, and common complaints were voice alteration while speaking loudly, changes in voice pitch, and voice disorder while singing. Changes in the Fo and Shimmer values in smokers versus nonsmokers were similar (Fo overall, p = 0.56; Shimmer overall, p = 0.66), as were the same parameters in benign and malignant pathologies (Fo overall, p = 0.66; Shimmer overall, p = 0.67). Voice changes after uncomplicated thyroidectomy occur and can be objectively measured. This is important in the preoperative counseling of patients before thyroidectomy, for ethical and legal purposes.Journal of the American College of Surgeons 11/2004; 199(4):556-60. · 4.50 Impact Factor