A series of thyroplasty cases under general anaesthesia

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.

A sequential anesthesia technique for surgical repair of unilateral vocal fold paralysis

Thyroplasty with arytenoid adduction, a combined procedure for treatment of unilateral vocal fold paralysis, is typically performed under local anesthesia with sedation to allow for intraoperative voice assessment. However, the need for patient immobility and suppression of laryngeal responses to surgical manipulation can make sedation-analgesia challenging. We describe our first 26 consecutive cases undergoing thyroplasty and arytenoid adduction with a standardized technique consisting of a combination of general anesthesia with tracheal intubation followed by sedation-analgesia. Most patients (69 %) were women, with age of 53 ± 15 years (mean ± SD). Neck surgery was the cause of vocal fold paralysis in 50 % of patients. Initially, general anesthesia was maintained with desflurane and remifentanil with dexmedetomidine added just before tracheal extubation. During the sedation-analgesia phase, patients received infusions of remifentanil and dexmedetomidine. Duration of general anesthesia and sedation-analgesia phases was 162 ± 68.2 and 79 ± 18.3 min, respectively. Mean (SD) wake-up time was 8.0 ± 4.0 min after desflurane discontinuation. Extubation occurred without coughing, bucking, or agitation in 96 % of patients. All the patients were able to phonate appropriately and remained comfortable after emergence. This technique allowed improved surgical conditions with reduced patient discomfort and may be advantageous for other laryngeal and neck surgeries in which intraoperative patient feedback is required.

Anesthetic considerations and surgical caveats for awake airway surgery

The evolution of novel techniques for the treatment of laryngeal pathology has led to a significant expansion of the role of diagnostic assessment and the range of laryngeal procedures performed. These procedures typically benefit from an anesthetic approach that diverges from a standard general endotracheal or laryngeal mask airway-based inhalational anesthetic. The shared airway, need for intraoperative assessment of vocal cord function, risk of airway fire, and desire for rapid emergence and discharge are all important factors. In this article the authors undertake a collaborative anesthesia-surgical discussion of anesthetic management for airway procedures that are optimally performed with a spontaneously breathing, cooperative patient. An overview of pharmacologic approaches to airway anesthesia and cooperative sedation, followed by a discussion on the surgical requirements and anesthetic goals of commonly performed procedures, are presented.

Laryngeal mask airways in ear, nose, and throat procedures

The use of laryngeal mask airway (LMA) and its variants in ear, nose, and throat procedures have been extensively described in case reports, retrospective reviews, and randomized clinical trials. The LMA has developed a considerable following because of its lack of tracheal stimulation, which can be a considerable advantage in ear, nose, and throat (ENT) procedures. The incidence of coughing on emergence has been shown to be lower with the LMA than with the endotracheal tube (ETT). Although other approaches to smooth emergence have been described, few would argue that it is as easy to achieve a smooth emergence with an ETT as with an LMA. Although patients certainly exist for whom the LMA is contraindicated, many will experience better results with the LMA because of the features delineated in this article.

Dexmedetomidine sedation for laryngeal framework surgery

OBJECTIVES

Sedation for laryngeal framework surgery has lacked easy modulation between appropriate pain control, airway protection, and the alertness appropriate for vocal testing. Our objective was to determine whether dexmedetomidine hydrochloride could safely and effectively be used as the sole intravenous anesthetic agent in conjunction with local anesthesia for laryngeal framework procedures.

METHODS

We undertook a prospective review of 14 patients who underwent laryngeal framework surgery with dexmedetomidine anesthesia in 2004 and 2005. All dexmedetomidine doses, sedation levels, and vital signs, including blood pressure, heart rate, respiratory rate, and oxygen saturation level, were recorded every 15 minutes by the anesthesiologist throughout the duration of the procedures. Operative conditions were noted by the surgeon, focusing special attention on airway protection, patient arousability, and patient comfort.

RESULTS

Dexmedetomidine sedation produced hemodynamic and respiratory values that were maintained near preoperative values, and overall pharyngeal-laryngeal integrity provided superior operating conditions for the patient and the operating surgeon.

CONCLUSIONS

We believe that dexmedetomidine provides excellent sedative and operative conditions for awake laryngeal framework procedures. Coupled with local anesthesia, dexmedetomidine produced virtually no undesirable hemodynamic or respiratory effects, while allowing for adequate sedation the majority of the time. The operative conditions were markedly improved over those of previous standard monitored anesthesia regimens.

Efficacy of total intravenous anesthesia without intubation for laryngeal framework surgery

CONCLUSION

Total intravenous anesthesia (TIVA) without intubation has the advantages of both conventional general anesthesia and local anesthesia. It is useful in laryngeal framework surgery because intraoperative voice monitoring while the patient remains awake is required.

OBJECTIVE

In laryngeal framework surgery, it is desirable to monitor the voice during surgery. However, surgery is conducted under general anesthesia, although such a procedure renders the patient unable to phonate during surgery. We conducted TIVA without intubation, allowing patients to breathe spontaneously while undergoing operation, and succeeded in intraoperative voice monitoring with satisfactory postoperative voice production.

SUBJECTS AND METHODS

The subjects were 21 patients who underwent surgery. For TIVA, propofol and pentazocine were used as a sedative and analgesic, respectively. A bispectral index (BIS) monitor was used to measure the depth of the anesthesia. Before the vocal folds were to be rotated, propofol administration was interrupted to arouse and instruct the patient to phonate. Guided by the phonation, the vocal folds were correctly positioned. Then propofol administration was resumed, and the wound was closed.

RESULTS

The BIS value during continued administration of propofol was around 60, but exceeded 90 in all patients within 233.6 +/- 64.5 s after cessation. They clearly remembered the conversation they had with us during surgery.

Thyroplasty under total intravenous anaesthesia with intermittent positive pressure ventilation

BACKGROUND AND OBJECTIVES

Medialization thyroplasty is a surgical technique for improving voice quality, cough effort and laryngeal competence in patients with unilateral vocal fold paralysis. Precision surgery is enabled by operating under total intravenous anaesthesia with controlled ventilation and by using a laryngoscopic video-assisted technique. The anaesthetic challenge is to manage the shared airway with the surgeon, provide a stable operative field and ensure patient safety throughout the procedure. The objective of this case series was to evaluate the use of a modified general anaesthetic technique using the laryngeal mask airway, total intravenous anaesthesia with controlled ventilation.

METHODS AND RESULTS

In all, 29 patients underwent medialization thyroplasty using a disposable laryngeal mask airway, total intravenous anaesthesia and controlled ventilation. Standard anaesthetic monitoring including capnography was used intraoperatively. Total intravenous anaesthesia was achieved using effect site target-controlled infusions of propofol and remifentanil.

CONCLUSIONS

The technique proved safe with stable haemodynamic observations and only two minor complications. It also provided the surgeon with stable view of the vocal folds in order to perform this precision surgery under an operating microscope.

A new procedure of arytenoid adduction combined with type I thyroplasty under general anesthesia using a laryngeal mask

Laryngeal framework surgery is usually performed under local anesthesia. However, some patients are unable to tolerate extended surgery. A case of an 82-year-old woman who underwent medialization thyroplasty and arytenoid adduction of direct lateral cricoarytenoid (LCA) muscle pulling at the same time under general anesthesia using a laryngeal mask is reported. Endoscopic observation through the laryngeal mask allows direct visual control of the vocal cord. The LCA pulling method does not touch the posterior border of the thyroid cartilage so that the laryngeal mask does not disturb the arytenoid adducts.