Is testing the voice under sedation reliable in medialization thyroplasty?

Is Sedation of Choice in Thyroplasty Surgery? A Study on the Effects of Sedatives on Voice Quality

OBJECTIVE

In order to establish the ideal anesthetic protocol in thyroplasty type I surgery, where the intraoperative voice test is used to guide the medialization of the paralyzed fold, we have studied the effects of a sedation with midazolam premedication and adjusted intravenous doses of propofol and remifentanil on voice quality in patients without vocal fold pathology undergoing otorhinolaryngology surgery other than thyroplasty.

STUDY DESIGN

Prospective cross-sectional study included 40 adult patients.

METHOD

A voice recording was performed when the patient was fully awake and when an appropriate level of conscious sedation was reached. Following premedication with midazolam at anxiolytic doses, remifentanil and propofol were administrated by target controlled infusion pumps (TCI). These results were compared with those obtained in a previous study carried out by the same team using intravenous bolus (IV) according to weight. The recorded voice analysis was performed using the computer program Praat (v.5.3.39) for a sustained vowel.

RESULTS

All the parameters obtained from the acoustic analysis of the voice were altered after sedation with target controlled infusion in a statistically significant way. Comparing with bolus intravenous, harmonic and noise ratio (HNR) was the only parameter that decreased less in the TCI group.

CONCLUSION

The state of sedation obtained using midazolam premedication, propofol and remifentanil adjusted intravenous doses alters significantly all the voice parameters, although this alteration is considerably less than the changes produced by the medication administered in bolus IV. According to these results, the sedation and the voice test during thyroplasty surgery would present a series of limitations when it comes to guiding the medialization of the paralyzed vocal fold and therefore it could not be considered as the ideal anesthetic protocol in thyroplasty surgery.

Anesthetic Technique and Functional Outcomes in Modified Montgomery Thyroplasty

BACKGROUND

Montgomery thyroplasty type I is a surgical technique indicated in vocal cord paralysis which consists of the paralyzed cord medialization, improving the voice quality. The objective of the study is to describe in detail the anesthetic method to obtain optimal post-medialization voice results.

METHODOLOGY

Retrospective case series study including patients who underwent medialization thyroplasty using the modified Montgomery technique at the General University Hospital of Valencia between 2011 and 2021. The anesthetic technique consisted of general anesthesia with neuromuscular relaxation and a laryngeal mask. Pre- and post-surgical vocal functional data of maximum phonation times (MPT), G score, and Voice Handicap Index-30 (VHI-30) were evaluated.

RESULTS

All the patients presented an improvement in voice results, increasing MPT after surgery and a decrease in VHI-30 and G score postoperatively, with statistically significant differences between the pre- and post-surgical results (p-value < 0.05). There were no complications related to anesthesia or surgery.

CONCLUSIONS

The use of general anesthesia with muscle relaxation in modified Montgomery thyroplasty may be a good option to consider. The use of a laryngeal mask for ventilation combined with a fiberoptic check allows direct visualization of the vocal cords intraoperatively, providing good functional voice results.

[Cervical plexus block as an alternative anesthetic approach for type I thyroplasty: a case report]

BACKGROUND

The role of type I thyroplasty (TIP) is well established as the treatment for glottal insufficiency due to vocal fold paralysis, but the ideal anesthetic management for this procedure is still largely debated. We present the case of a novel anesthetic approach for TIP using combined intermediate and superficial Cervical Plexus Block (CPB) and intermittent mild sedation analgesia.

CASE REPORT

A 51-year-old presenting with left vocal fold paralysis and obstructive sleep apnea was scheduled for TIP. An ultrasound-guided intermediate CPB was performed using the posterior approach, and 15 mL of ropivacaine 0.5% were injected in the posterior cervical space between the sternocleidomastoid muscle and the prevertebral fascia. Then, for the superficial CPB, a total of 10 mL 0.5% ropivacaine was injected subcutaneously, adjacently to the posterior border of the sternocleidomastoid muscle, without penetrating the investing fascia. An intermittent sedation analgesia with a target-controlled infusion of remifentanyl (target 0.5 ng.mL^-1) was used to facilitate prosthesis insertion and the fiberoptic laryngoscopy. This technique offered a safe anesthetic airway and good operating conditions for the surgeon, as well as feasible voice monitoring and optimal patient comfort.

CONCLUSION

The use of regional technique is a promising method for the anesthetic management in TIP, especially in patients with compromised airway.

Cervical plexus block as an alternative anesthetic approach for type I thyroplasty: a case report

Background

The role of type I thyroplasty (TIP) is well established as the treatment for glottal insufficiency due to vocal fold paralysis, but the ideal anesthetic management for this procedure is still largely debated. We present the case of a novel anesthetic approach for TIP using combined intermediate and superficial Cervical Plexus Block (CPB) and intermittent mild sedation analgesia.

Case report

A 51-year-old presenting with left vocal fold paralysis and obstructive sleep apnea was scheduled for TIP. An ultrasound-guided intermediate CPB was performed using the posterior approach, and 15 mL of ropivacaine 0.5% were injected in the posterior cervical space between the sternocleidomastoid muscle and the prevertebral fascia. Then, for the superficial CPB, a total of 10 mL 0.5% ropivacaine was injected subcutaneously, adjacently to the posterior border of the sternocleidomastoid muscle, without penetrating the investing fascia An intermittent sedation analgesia with a target-controlled infusion of remifentanyl (target 0.5 ng.mL^-1) was used to facilitate prosthesis insertion and the fiberoptic laryngoscopy. This technique offered a safe anesthetic airway and good operating conditions for the surgeon, as well as feasible voice monitoring and optimal patient comfort.

Conclusion

The use of a regional technique is a promising method for the anesthetic management in TIP, especially in patients with compromised airway.