Laser-assisted posterior cordotomy for bilateral vocal fold paralysis: Our experience :Nitish Virmani, Jyoti Dabholkar, Journal of Head & Neck Physicians and Surgeons

ORIGINAL ARTICLE
Year : 2016 | Volume : 4 | Issue : 1 | Page : 23--28

Laser-assisted posterior cordotomy for bilateral vocal fold paralysis: Our experience

Nitish Virmani, Jyoti Dabholkar
Department of ENT and Head-Neck Surgery, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India

Correspondence Address:
Nitish Virmani
H. No. 576, Sector-37, Faridabad - 121 003, Haryana
India

Abstract

Introduction: Bilateral vocal fold paralysis (BVFP) is a relatively uncommon cause of respiratory distress. The goals of surgical treatment are an improvement in airway size by enlarging the glottis, thus, eliminating the need for tracheostomy, while at the same time avoiding a breathy voice and aspiration. Striking this balance is extremely important. Unilateral laser-assisted posterior cordotomy provides sufficient airway at posterior glottis while preserving phonatory and protective functions of the larynx. Aims: To evaluate long-term acoustic, aerodynamic and functional results of laser-assisted unilateral posterior cordotomy in BVFP. Materials and Methods: The prospective study includes seven patients of BVFP who underwent unilateral laser-assisted posterior cordotomy. Surgical success was evaluated regarding decannulation rate, time to decannulation and need for the second procedure. Voice assessment was done using voice handicap index (VHI), grade, roughness, breathiness, asthenia, strain and measurement of maximum phonation time (MPT). Effect of deglutition was assessed by the presence or absence and duration of aspiration. Observations and Results: Of seven patients, four had been tracheostomized at some time during their treatment. They were successfully decannulated within an average of 1 week after the surgery. The postoperative respiratory function was adequate for more than routine activity in all patients. None of the patients required a second procedure. VHI values demonstrated that while four patients had no/mild degree of voice handicap, two had moderate and one had a severe degree of handicap. While five patients had a normal MPT, two had a reduced MPT. Perceptual rating by a speech pathologist revealed that while two patients had mild dysphonia, four had moderate dysphonia. None of the patients complained of aspiration postoperatively. Conclusion: Unilateral CO₂laser posterior cordotomy is a simple, safe and short surgical technique that creates a satisfactory glottic airway to improve respiration while avoiding aspiration and having minimal to the mild effect on the voice.

How to cite this article:
Virmani N, Dabholkar J. Laser-assisted posterior cordotomy for bilateral vocal fold paralysis: Our experience.J Head Neck Physicians Surg 2016;4:23-28

How to cite this URL:
Virmani N, Dabholkar J. Laser-assisted posterior cordotomy for bilateral vocal fold paralysis: Our experience. J Head Neck Physicians Surg [serial online] 2016 [cited 2023 Jun 4 ];4:23-28
Available from: https://www.jhnps.org/text.asp?2016/4/1/23/182852

Full Text

Introduction

Bilateral vocal fold paralysis (BVFP) is a relatively uncommon cause of respiratory distress. The adducted/para-median position of the true cords results in a severely compromised airway at rest or on exertion with a relatively unaffected voice. Rehabilitation of bilaterally paralyzed larynx continues to remain a surgical challenge for the otolaryngologist who strives to create a balance between the creation of an adequate airway and preservation of voice and protective function of the larynx. Unilateral vocal fold paralysis is more common than BVFP, however the exact incidence of BVFP is unknown in the current literature.[1] Etiologies of BVFP include surgical trauma (44%), malignancies (17%), endotracheal intubation (15%), neurologic causes (12%), and idiopathic cases (12%).[2] The most common cause remains iatrogenic injury during thyroidectomy.[3] Airway compromise resulting from insufficient glottic chink often necessitates a tracheostomy to bypass the paralyzed larynx. Although permanent tracheostomy may provide the best possible airway as far as size is concerned, this is only a temporary measure because of numerous complications associated with a long-term tracheostomy. Many surgical techniques have been described to treat BVFP ranging from options as simple as a ventriculocordectomy by Chevalier Jackson in 1922 as a glottis widening procedure, to as complex as reanimation of the larynx with an electrical device.[4],[5] The ideal surgical technique for this condition should be able to relieve the airway obstruction while preserving laryngeal functions such as phonation and airway protection. Posterior transverse laser cordotomy was first described by Dennis and Kashima as a technique for providing an airway at the posterior glottis without preoperative tracheotomy; they reported it as a successful method with satisfactory functional results.[6] The aim of this prospective study was to evaluate long-term acoustic, aerodynamic, and functional results of laser-assisted unilateral posterior cordotomy in seven cases of BVFP.

Materials and Methods

This prospective study was conducted in the Otorhinolaryngology department of our hospital, a tertiary care referral center, from November 2014 to January 2016. Seven patients who presented to our OPD with BVFP and ultimately underwent CO2 laser posterior cordotomy as the surgical procedure were included in the study. Written informed consent was obtained from all patients. They underwent a detailed history and clinical examination to confirm the diagnosis and to determine the etiology of vocal cord palsy [Figure 1]. Contrast-enhanced computed tomography (skull base to chest) was done for cases other than iatrogenic to exclude organic lesions. All patients underwent unilateral posterior cordotomy using CO2 laser.{Figure 1}

Surgical technique

The surgical procedure was performed using suspension microlaryngoscopy under general anesthesia. Ventilation was maintained either through tracheostomy tube or a cuffed endotracheal laser tube in nontracheostomised patients. Neurosurgical patties moistened with saline were placed in subglottis to protect the cuffed tube from thermal damage. We used the CO2 laser with micromanipulator in a super pulse mode. The vocal process of arytenoid cartilage was identified using a suction tip [Figure 2]. The part of vocal cord just anterior to it was vaporized transversely by laser including the entire vocalis and thyroarytenoid muscle [Figure 3]. Care was taken to avoid injury to the vocal process. Contraction and retraction of the vocalis muscle would lead to a wedge-shaped defect in the posterior cord, thus, improving the glottic chink to about 5–6 mm [Figure 4]. The false vocal cord was vaporized to bring the diameter of the opening to match with tracheal wall.{Figure 2}{Figure 3}{Figure 4}

Postoperatively, patients were given a short course of antibiotics, steroids and steam inhalation [Figure 5]. The trial of decannulation was given on fifth postoperative day for tracheostomized patients, and they were finally decannulated within a week.{Figure 5}

Outcome analysis

Patients were followed-up regularly for a minimum period of 6 months. Surgical outcome was assessed by following measures:

Respiration: Respiratory function was assessed by grading dyspnea and stridor according to NYHA scores. Surgical outcome was evaluated regarding decannulation rate, time to decannulation and need for a second procedure Voice analysis: Multidimensional assessment of voice characteristics was done by a certified speech-language pathologist at 6 months postoperatively. Patient's perception was evaluated by voice handicap index (VHI). The voice was graded subjectively by a speech pathologist based on grade, roughness, breathiness, asthenia, strain (GRBAS) score Swallowing: Effect on deglutition was assessed by the presence or absence and duration of aspiration.

Observations and Results

The study included seven patients of BVFP. There were two male (28.57%) and five female (71.42%) patients. The age of patients ranged from 19 to 52 years, with the mean being 36.1 years [Table 1].{Table 1}

The most common etiological factor was iatrogenic, i.e., a result of previous thyroid surgery in four patients (66.7%). In one patient, a young man of 22 years, the cause was syringomyelia and syringobulbia, involving the brainstem and the spinal cord. Consequently, he had developed bilateral cord palsy, difficulty in swallowing and weakness of upper and lower limbs. He had been put on feeding through percutaneous endoscopic gastrostomy tube (PEG). Shunt procedures were done to drain cerebrospinal fluid following which his swallowing improved. At least three attempts at decannulation were made at an outside center but each time, he had to retracheostomized. No causative factor could be found for two patients (33.3%) even after appropriate radiological and evaluation and they were thus labeled as idiopathic.

Four of these patients presented to us with long-standing complaints of respiratory distress and stridor precipitated during ordinary activity and while sleeping at night. These patients had not required a tracheostomy during this period. One of these four, however, required an intra-operative tracheostomy due to the poor exposure of the posterior glottis. Three of the six patients, however, had presented with severe respiratory distress and stridor at rest requiring an emergency tracheostomy. Thus, overall, 4 out of 7 patients were tracheostomized at some point during their treatment (before laser surgery).

One patient had been previously operated outside by bilateral posterior cordectomy. However, her symptoms had returned within 3 months after the procedure with the same severity as during the preoperative period. This necessitated a revision procedure.

All patients underwent unilateral posterior cordotomy using CO2 laser as described previously.

Respiration

The four tracheostomized patients were successfully decannulated within an average of 1 week after the surgery. Thus, the decannulation rate was 100%. None of the patients required a second procedure [Figure 6].{Figure 6}

Postoperative respiratory function was adequate for more than routine activity in all patients. They could climb an average of four flights of stairs without getting breathless or stridorous. None of them had noisy breathing or stridor while sleeping at night.

Phonation

Effect on phonation was studied by three parameters: VHI, maximum phonation time (MPT) and GRBAS score. VHI values demonstrated that while four patients had no/mild degree of voice handicap, two patients had moderate and one patient had a severe degree of handicap. While five patients (66.7%) had a normal MPT (above 10), two patients (33.3%) had a reduced MPT (10 or below). Perceptual rating by a speech pathologist revealed that while two patients had mild dysphonia (Overall grade of 1), four patients had moderate dysphonia (overall grade of 2) [Table 2].{Table 2}

Swallowing

None of the patients in our study complained of aspiration postoperatively. The young man with syringomyelia had improved swallowing after the shunt procedures. PEG tube was removed postoperatively and he could resume normal oral feeding.

Discussion

BVFP has always been a surgical dilemma for the otolaryngologist. While unilateral vocal cord palsy allows for normal ventilation, reduction of airway area in BVFP can be life-threatening. Both voice and airway are affected in this condition. Airway compromise due to impaired abduction of cords results in respiratory distress in the form of inspiratory stridor, which can be severe enough to warrant tracheostomy. Although permanent tracheostomy may provide the best possible airway for these patients as far as airway size is concerned, a permanent tracheostomy is not without its own problems. Complications include tracheal stenosis, chronic infection, and psychosocial impairment.[7],[8],[9] This underlies the need for laryngeal surgery in these patients.

The goals of surgical treatment are an improvement in airway size by enlarging the glottis, thus, eliminating the need for tracheostomy, while at the same time avoiding a breathy voice and aspiration. Striking this balance is extremely important. Many surgical techniques have been proposed, making use of extralaryngeal as well as endoscopic approaches [Table 3]. The use of extralaryngeal approaches was introduced in 1922 by Jackson, who advocated a ventriculocordectomy whereby the entire vocal cord and ventricle was excised.[4] This created an excellent airway but resulted in a breathy voice. Submucosal resection of vocal fold proposed by Hoover resulted in excessive scarring, thus leading to glottic stenosis and postoperative dysphonia.[10] In 1946, Woodman proposed another technique for arytenoidectomy with the use of a posterolateral extralaryngeal approach in addition to suturing the vocal process to the inferior cornu of the thyroid cartilage to lateralize the vocal fold.[11] This technique is still considered one of the most significant transcervical approaches. Endoscopic approaches were subsequently introduced; including Thornell's arytenoidectomy [12] by electrocautery and CO2 laser arytenoidectomy by Ossoff et al.[13] Remacle et al. proposed the so-called subtotal arytenoidectomy by resecting the body of the arytenoid and preserving only a small posterior shell, which should protect the airway from aspiration.[14] However, the enlargement of the glottis chink may be only moderate unless additional submucosal cordectomy and lateralization are performed. Plouin-Gaudon et al. gave their long-term results on subtotal arytenoidectomy, indicating that the advantage of subtotal arytenoidectomy lied in the fact that it maintained a certain degree of rigidity along the posterior limit of the arytenoid frame, preventing inward collapse of the mucosa and thus lowering the risk of aspiration.[15] Crumley introduced the endoscopic laser medial arytenoidectomy where a resection of the medial part of the arytenoid body is performed under preservation of its complete lateral, posterior, and inferior aspects and the vocal process.[16] Bosley et al. determined that medial arytenoidectomy had the ability to enlarge laryngeal airway in BVFP and that it had minimal adverse effect on phonatory and swallowing function.[17]{Table 3}

In 1989, Dennis and Kashima introduced posterior cordotomy.[6] It consists of a transverse incision of the vocal fold in front of its insertion into the vocal process. It should completely cut the elastic cone and reach the perichondrium. Some authors perform a wedge excision of the vocal cord anterior to vocal process (cordectomy), however, we have found that it is not necessary. A transverse incision in the vocal cord (cordotomy) creates a wedge-shaped defect due to contraction and retraction of vocalis muscle.

Some authors extend the procedure to involve both vocal folds. Khalifa in his series of 22 cases did not report any complications related to deglutition, aspiration, or granuloma formation after performing bilateral posterior cordotomy.[18] We have had satisfactory outcomes with a unilateral procedure regarding airway size, decannulation rate and improvement in dyspnea. None of our patients required a second or a revision surgery. One of our patients had been operated on bilateral cords at an outside center, but her symptoms had returned shortly after the procedure. Intra-operatively, we found that the cordotomy of both sides had closed by fibrosis. Even in this patient, we performed a unilateral procedure with an excellent outcome.

We have used the VHI and the perceptual analysis for assessment of voice outcome. Only one of our patients reported a severe handicap on VHI scoring and a reduced MPT. She was, however, satisfied with the surgical outcome. Some amount of breathiness in voice is expected sequelae of this procedure since a permanent posterior glottic gap is being created. Thermal or laser damage to anterior part of vocal cords must be avoided to preserve the vibratory function and reduce the postoperative roughness in voice.

In our series, none of the patients complained of aspiration. Eckel et al. compared the results of patients treated with posterior cordotomy with those of a group of patients treated with complete arytenoidectomy. He found that both techniques were equally effective for achieving a functional airway, but patients treated with complete arytenoidectomy had more subclinical aspiration.[19] Lawson et al. also stated that arytenoidectomy resulted in subclinical aspiration while posterior cordotomy did not lead to this problem after surgery.[20]

Various local complications have been reported following laser cordotomy including granuloma formation, perichondritis, postoperative scarring. Khalil et al. reported the formation of vocal fold granuloma in three patients not requiring revision surgery.[21] In Özdemir et al.'s study, four patients suffered from the formation of vocal fold granuloma, and all of them needed a second intervention.[22] However, we did not experience any of the above complications in our patients. Certain precautions are necessary to avoid these such as removal of charring with saline-soaked patties, avoiding injury to vocal process of arytenoid by correctly identifying it and vaporizing the tissue just anterior to it.

Local complications have been reported more often after arytenoidectomy. Arytenoidectomy with the removal of the covering mucosa for glottic airway restoration is very susceptible to granuloma and scar formation. A raw surface in the larynx may cause excessive scar formation and scar contracture, which inevitably leads to a re-narrowing of the airway because the defect is not well covered with mucosa.[23],[24] Antonio et al. in his 18 cases of BVFP reported that granulation tissues formed in the arytenoid resection bed in two patients, which required surgical re-exploration. Transitory aspiration occurred in four patients and resolved spontaneously.[25]

Emerging research has shown that laryngeal reinnervation is a promising technique for BVFP.[26],[27] Re-innervation techniques, however, are still primarily in the research stage, with surgeries being performed only at select centers, but there are positive preliminary outcomes suggesting promise for bilateral vocal cord paralysis patients in the future, particularly in younger BVFI patients.[28]

Conclusion

Unilateral CO2 laser posterior cordotomy is a simple, safe and short surgical technique that creates a satisfactory glottic airway to improve respiration while avoiding aspiration and having minimal to the mild effect on voice. Local complications at the cordotomy bed can be avoided by following a few precautionary measures.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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