A New and Less Invasive Procedure for Arytenoid Adduction Surgery: Endoscopic-Assisted Arytenoid Adduction Surgery

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1 The Laryngoscope VC 2011 The American Laryngological, Rhinological and Otological Society, Inc. A New and Less Invasive Procedure for Arytenoid Adduction Surgery: Endoscopic-Assisted Arytenoid Adduction Surgery Takaaki Murata, MD, PhD; Yoshihito Yasuoka, MD; Tetsuaki Shimada, MD; Masato Shino, MD, PhD; Hideki Iida, MD; Katsumasa Takahashi, MD, PhD; Nobuhiko Furuya, MD, PhD Objectives/Hypothesis: Arytenoid adduction (AA) is the most effective procedure for improving voice function in patients affected by unilateral vocal fold paralysis (UVFP), but it is often associated with severe complications following airway obstruction. The aim of this study is to describe a new and less invasive AA surgical procedure termed endoscopicassisted AA surgery (EAAS) and to evaluate its voice outcomes. Study Design: We demonstrated this method using extirpated larynges from three laryngeal cancer patients. Ten patients with severe UVFP underwent EAAS alone or combined with type I thyroplasty or lipoinjection laryngoplasty. Methods: EAAS involves the placement of permanent adducting sutures around the muscular process (MP) of the arytenoid cartilage using two needles, a penetration needle and a loop needle, under endoscopic guidance. To define the anatomic position of the MP for safer needle insertion, the location of the MP was measured relative to three landmarks on computed tomography/x-ray images of the larynges and in resected larynges. For all patients with UVFP, the maximum phonation time, mean airflow rate, and three acoustic analysis parameters were measured before and after EAAS. Results: The values of the three variables were similar in all cases. Most patients achieved a maximum phonation time of more than 10 seconds and a mean airflow rate of less than 200 ml/second. All three acoustic analysis parameters were significantly improved after surgery. Conclusions: EAAS is a simple and effective arytenoid rotation procedure. Key Words: Arytenoid adduction, endoscopic surgery, vocal fold paralysis. Level of Evidence: 2c. Laryngoscope, 121: , 2011 INTRODUCTION Patients with unilateral vocal fold paralysis (UVFP) present with varying degrees of dysphonia, dysphagia, and/or aspiration risk. In the management of severe UVFP, arytenoid adduction (AA) surgeries are important procedures. They are particularly suitable for correcting the vocal fold level and closing pronounced posterior glottic chinks. The standard AA surgical procedure requires posterior dissection of the thyroid cartilage to gain access to the muscular process (MP) of the arytenoid cartilage. 1,2 However, this procedure is often associated with a risk of perforating the piriform sinus, bleeding, and edema of the larynx following airway obstruction. 3 Thus, a less invasive procedure for AA surgery is desired for both patients and surgeons. Meanwhile, in the management of bilateral vocal fold paralysis, Ejnell reported a less traumatic, laryngeal endoscopic guided suture technique for vocal fold From the Department of Otolaryngology, Gunma University Graduate School of Medicine, Gunma, Japan. Editor s Note: This Manuscript was accepted for publication January 24, The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Takaaki Murata, Department of Otolaryngology, Gunma University Graduate School of Medicine, Showamachi, Maebashi, Gunma , Japan. tmurata@showa.gunma-u.ac.jp DOI: /lary abduction. 4 This procedure involves permanently suturing the vocal folds laterally by using needles, and the degree of vocal fold abduction can be verified by indirect laryngoscopy. The only reported adverse effect of this procedure was moderate edema of the vocal folds and arytenoid cartilage. Thus, based on Ejnell s method, we designed a simple, less invasive AA method for UVFP in which we used looped traction nylon thread under laryngeal endoscopic guidance. This study aims to describe our new and less invasive method and evaluate the resultant voice outcomes. In this method, it is important that the location of the MP is precisely identified before the needle is inserted from the cricothyroid ligament. To define the anatomic position of the MP, its location is measured relative to other landmarks using both computed tomography (CT) and X-ray imaging of the larynges and resected specimens. To evaluate the clinical efficacy of this method, we performed aerodynamic and acoustic analyses in 10 patients who had received endoscopicassisted AA surgery (EAAS) alone or combined with another medialization laryngoplasty. MATERIALS AND METHODS Anatomic Measurements In this study, we describe the principle behind and the surgical procedure for our method. Before performing the

2 Surgical Procedure The operation is performed with general anesthesia. The patient is ventilated via a small endotracheal tube (6.5-mm outer diameter spiral tube). The tip of the tube is inserted close to the tracheal carina. Two surgeons operate at the same time: one operates externally on the neck, and the other performs endoscopic hypopharyngeal surgery using a curved laryngopharyngoscope (Sato-style) (Nagashima Medical Instruments, Tokyo, Japan) and a laryngeal videoendoscope (ENF TYPE VQ; Olympus Japan Inc., Tokyo, Japan) (Fig. 2A). The external surgeon makes an approximately 3-cm-long horizontal skin incision at the level of the cricothyroid ligament. The strap muscles are then separated at the midline, and the cricothyroid ligament is exposed. Before the insertion of the needles, the landmarks are drawn on the skin and cricothyroid ligament (Fig. 3). A horizontal line is then drawn parallel to the superior edge of the thyroid cartilage at the level of the vertical midpoint of the thyroid cartilage. After on the cricothyroid ligament based on a, c is marked as the intersection of the line at a degrees to the frontal neck tangent line with the lateral edge of the thyroid cartilage. Fig. 1. (A) Axial computed tomography image of the vocal fold and (B) the lateral X-ray view; lengths a, b, and c were calculated, and angle a was measured. Insertion was marked. The open dot indicates the muscular process. procedure, we defined the three landmarks described here and measured various distances and angles on CT/X-ray images. The distance from the midline of the thyroid cartilage to the MP ( a ) was measured (Fig. 1A), and the insertion point ) was defined as the point found at a distance of a lateral from the midline of the cricothyroid ligament on the axial CT image. The distance to the MP ( b ), which represents the needle insertion line, was measured, and the intersection of the extended insertion line with the lateral edge of the thyroid cartilage ( c ) was marked on a lateral X-ray of the larynx; a is the horizontal angle between the insertion line and the midline of the thyroid cartilage on the lateral X-ray view (Fig. 1B). Objective Evaluation of Anatomic Measurement To verify the reliability of our imaging measurements, the recorded data were compared to the actual values of curatively extirpated larynges from three laryngeal cancer patients. Duplicate measurements were recorded by a second researcher (blinded with respect to the initial data), and the two data sets were averaged. Fig. 2. Supportive instruments for endoscopic arytenoid adduction. (A) The direct laryngopharyngoscope used for endoscopic hypopharyngeal surgery was helpful for wide dilation and viewing of the piriform sinus during the insertion of the needles and the thread manipulation. (B) Upper image: penetration needle. Lower image: loop needle. To prevent penetration beyond the estimated distance c, the thread-bearing ends of the needles were sheathed in silicon tubes of appropriate lengths. 1275

3 depth of insertion should be within b þ 5 mm. After confirming that the needle tip has been correctly positioned, it is pushed toward the MP, and adduction of the vocal fold is performed under video monitoring. If the vocal fold does not turn outward in spite of the cartilage being pushed, the tip may touch the posterior wall of the cricoid cartilage. In such cases, the needle should be pulled back slightly and directed upward. When the arytenoid has been moved backward, the needle tip may put pressure on the medial or superior portion of the arytenoid cartilage. The risk of damaging the nearby larynx and hypopharynx is high if the needle is inserted far beyond the planned distance. After appropriate adjustment of the MP, the needle is pointed downward and protrudes into the piriform sinus near the cricoarytenoid joint (Fig. 4). The loop needle is then inserted a few millimeters above the penetration needle. The loop needle is passed above the MP and thrust into the piriform sinus. Under endoscopic guidance, the single line nylon thread projecting from the tip of the penetration needle is passed through the looped thread of the loop needle with forceps. The needles and looped thread are then withdrawn. The single line thread thus forms a loop around the MP. The external surgeon then tightens the loop until the endoscopist judges that the vocal fold Fig. 3. (A) Anterior view and (B) lateral view of the neck skin. The skin incision line, the superior border of the thyroid cartilage, and the vertical midpoint line of the thyroid cartilage, which is located at a similar level to the vocal fold, are shown. The protractor indicates the insertion angle a. C is marked as the intersection of the line at a degrees to the frontal neck tangent line with the lateral edge of the thyroid cartilage. Two needles (23 gauge, 5.5 cm) are inserted through the cricothyroid ligament: one needle carrying a single line 3-0 nylon monofilament thread (penetration needle) and another needle carrying looped nylon thread (loop needle) (Fig. 2B). With video monitoring of the larynx by means of a transoral flexible laryngoscope, the external surgeon inserts the penetration needle on the cricothyroid ligament in the sagittal direction toward c and directly into the paraglottic space to avoid intraluminal penetration of the trachea. The Fig. 4. (A) Schematic posterior view of the larynx; appropriate needle push-out points (dots) are drawn on the piriform sinus. (B) Endoscopic view of the piriform sinus; a single line nylon thread is passed through the looped thread. 1276

4 Fig. 5. The principle of endoscopicassisted arytenoid adduction surgery. (A) Schematic axial view of the larynx shows that the penetration needle and the loop needle are inserted from the cricothyroid ligament toward the piriform sinus, nearly passing through the muscular process. (B) The retracted nylon threads are tightened with a spacer at the cricothyroid ligament, and the arytenoid cartilage is successfully adducted. (C) A model larynx showing the manner in which the penetration needle should be passed near to the muscular process (left image: posterosuperior view; right image: lateral view; a indicates the insertion angle). has been sufficiently adducted. The thread is then tied between a spacer, such as an EndoButton (Smith & Nephew, Memphis, TN), to facilitate retightening if necessary. Figure 5 shows the principle behind EAAS, and a model larynx indicates the manner in which the penetration needle should be passed near to the MP. Gunma University Hospital Institutional Review Board approved this study (accession number: 780). Application Procedure and Vocal Functional Evaluation Based on the anatomic information and surgical procedure, endoscopic AA was performed in 10 patients (3 males, 7 females, age range: years) between October 2007 and December Informed consent was obtained from all patients. Our institutional criteria for EAAS included an appropriate age (20 80 years), a confirmed diagnosis of UVFP, and more than 3 months having elapsed from the onset of UVFP. Patients complicated with dysarthria were excluded from the study because of the difficulty of phonational evaluation. All surgical procedures were successful. However, two of the 10 patients were allowed to recover from the general anesthetic before the loop thread was tightened because it was desirable for the patients to phonate during the operation. In this study, we performed EAAS with or without type I thyroplasty or injection laryngoplasty because AA surgery is particularly suitable for correcting the vocal fold level and the closure of pronounced posterior vocal chinks. 5 The maximum phonation time (MPT) and mean airflow rate (MFR) were recorded before and after each surgery by using a sustained vowel (/a/) at a comfortable pitch and volume in all patients. The jitter, shimmer, and harmonics-to-noise ratio were also analyzed before and after each surgery. A Computer Speech Laboratory (model 4400; Kay Elemetrics Inc., Lincoln Park, NJ) and SPSS statistics 17.0 software (IBM, Somers, NY) were used for the data analysis. The data obtained from 6 months to 3 years postoperatively were used to assess the surgical outcome. All parameters were statistically compared from before and after surgery using the Wilcoxon signed rank sum test. RESULTS Consistency of Anatomic Measurements Between the Images and Extirpated Larynges To improve the proportion of correct needle insertions, we compared our measurements that is, the distance from the midline of the thyroid cartilage to the MP ( a ), the distance from the insertion point to the MP ( b ), and the horizontal angle between the insertion line and the midline of the thyroid cartilage ( a ) between the acquired images and extirpated larynges. 1277

5 TABLE I. Three Measurements Taken from Computed Tomography/X-Ray Images and Extirpated Larynges. a b a Extirpated Larynx Sex/Age (yr) CT Larynx X-ray Larynx X-ray Larynx 1 M/ M/ F/ Mean a ¼ distance from the midline of the thyroid cartilage to the muscular process in millimeters; b ¼ distance from the insertion point to the muscular process in millimeters; a ¼ horizontal angle between the insertion line and the midline of the thyroid cartilage; CT ¼ computed tomography; M ¼ male; F ¼ female. Although statistical analysis could not be performed because of the low sample number, the measurement values were similar for each parameter (Table I). In addition, we confirmed that our procedure resulted in successful adduction of the MP by passing a nylon thread around the MP using an extirpated larynx (Supplemental Movie 1). These results suggest that measurements from X-ray/CT images can assist in inserting the needles to the correct position in this procedure. Clinical Procedure and Vocal Functional Evaluation Clinical data for the 10 patients are listed in Table II. There were three cases of EAAS alone, three cases of EAAS with type I thyroplasty, and four cases of EAAS with lipoinjection laryngoplasty. The values of the anatomic measurements mentioned for each patient are listed in Supplemental Table I. Most patients achieved an MPT of more than 10 seconds (Table III). Their MFR values also improved to less than 200 ml/second, except in one case of EAAS alone (387 ml/second), in which severe vocal fold atrophy might have affected the MFR value. Based on the preoperative data for shimmer, jitter, and harmonics-to-noise ratio, the improvement in these three factors after surgery was estimated. EAAS alone also achieved improvements in MPT and MFR, respectively, compared with EAAS combined with type I thyroplasty or lipoinjection laryngoplasty. We did not observe any major complications such as excessive pain, airway obstruction requiring a tracheostomy, dysphagia, or wound infection. Minor complications occurred in two cases: a small sized paraglottic space hematoma and penetration of the endotracheal tube. DISCUSSION Since the AA method was first described by Isshiki, 1 it has become an important technique along with medialization laryngoplasty such as type I thyroplasty and injection laryngoplasty, especially for the correction of the vocal fold level and the closure of posterior glottic chinks. 5,6 Several modified versions of Isshiki s procedure have been reported for the purpose of improving its specificity and direct clinical applicability. 2,7 9 However, all previously reported AA procedures involved dissection of the posterior portion of the thyroid cartilage and removal of the hypopharyngeal mucosa to gain access to the MP. These procedures carry a risk of mucosal laceration, bleeding, or edema of the larynx following airway obstruction requiring tracheostomy. 3,10 In this study, we demonstrated a novel AA procedure involving Ejnell s less traumatic suture technique for vocal fold abduction and the use of several instruments under endoscopic guidance. 4 This endoscopic AA TABLE II. Summary of 10 Cases Treated with Endoscopic Arytenoid Adduction. Case No. Sex/Age (yr) Combined Operation Preop Postop Preop Postop 1 M/42 None , M/67 None F/68 None F/72 Lipoinjection F/69 Lipoinjection F/24 Lipoinjection F/43 Lipoinjection M/71 Type I TP F/54 Type I TP F/72 Type I TP MPT (s) MFR (ml/s) MPT ¼ maximum phonation time; MFR ¼ mean airflow rate; Preop ¼ preoperative; Postop ¼ postoperative; M ¼ male; F ¼ female; TP ¼ thyroplasty. 1278

6 Variables TABLE III. Results of Acoustic Analysis Before and After Surgery. Preoperative (Mean 6 SD) Postoperative (Mean 6 SD) P Value MPT (s) * MFR (ml/s) * Shimmer (%) * Jitter (%) * HNR * *Statistically significant at P <.05 SD ¼ standard deviation; MPT ¼ maximum phonation time; MFR ¼ mean airflow rate; HNR ¼ harmonics-to-noise ratio. procedure does not involve cutting the thyroid cartilage or exposing the MP; thus, it may reduce the risk and complications associated with AA surgery. Although there are limited numbers of clinical cases available for analysis, no major complications such as airway obstruction have occurred. A larger population would be helpful to support further refinement of the technique, and an interventional trial between conventional AA and our reported novel EAAS procedure would provide more accurate information about the incidence rate of complications. In AA surgery, identifying the location of the MP is important for both safety and success, and several reports have described less invasive methods for identifying the MP. 2,11,12 In EAAS, the most difficult tasks are aiming the penetration needle at the MP during its insertion through the cricothyroid space and intraluminal penetration of the piriform sinus. These tasks could result in failure or complications such as hematoma, mucosal laceration, and penetration of the endotracheal tube, especially when the procedure is performed by inexperienced surgeons. We recommend that, before one performs clinical procedures, many practice trials with cadaveric or clinically resected larynges, in which precise movement of the MP should be confirmed during needle insertion. The anatomic guidelines covering the procedure aid appropriate insertion and identification of the MP. Unlike conventional AA, in which the MP, lateral cricoarytenoid muscle, and thyroid cartilage are exposed, EAAS is performed in a limited area. Therefore, we analyzed anatomic information related to the depth and angle of the inserted needle using CT and lateral X-ray views and resected larynges from three patients with laryngeal cancer. The measurement values were similar between the images and the larynges in our study. Considering the individual and sex variability of the human larynx, it is necessary to incorporate multiple local anatomic landmarks from individual images and surgical techniques to identify the MP. Therefore, we applied the data obtained from the images to clinical trials of endoscopic AA, and the expected results were obtained with respect to MP identification, with only a few needle reinsertions required. For precise insertion of the needle toward the MP, it is necessary that the piriform sinus be sufficiently open to allow observation of the mucosal penetration of the needle. The curved laryngopharyngoscope (Sato style) is a very helpful device for this purpose and for avoiding extra mucosal damage. Observing the movement of a paralyzed vocal fold during the needle insertion is important for evaluating whether the inserted needle has passed through the correct position. Monitoring vocal fold movement and needle penetration with laryngeal endoscopy helps surgeons insert the needle to an accurate position. In EAAS, the pull method of percutaneous endoscopic gastrostomy is applied to monitor the retraction of the MP. 13 This method is quite simple and atraumatic and uses a small amount of nylon thread and conventional needles. The threads that retract the MP are tied between a spacer to facilitate retightening when necessary. Retightening the threads is possible under local anesthesia while the patient provides information about their voice and vocal folds, such as their tone of voice, vocal fold vibration, and the slit between the vocal folds during phonation. Using this method, the patient can understand the condition of their own vocal folds and voice and order the retraction of the threads to be adjusted to their satisfaction. EAAS is performed with general anesthesia to allow the curved laryngopharyngoscope to be inserted transorally. Thus, to test phonation during surgery, the patient needs to recover from the general anesthesia before the loop thread is tightened. However, even under local anesthesia, the patient sometimes cannot produce good phonation during surgery owing to the influence of sedation, atrophy of the paralyzed fold, and the physical and emotional burden placed on them by the surgery. Endoscopy might aid the surgeon in confirming that the adduction was performed accurately, even with intubation. In the end, the surgical approach chosen for AA might depend on the patient s wishes. The mean operation time of EAAS alone was 114 minutes, which is not much longer than that of standard AA. From the viewpoint of the minimal invasiveness of the operative procedure, we think that the operation time of EAAS is acceptable. Unlike conventional AA, EAAS requires CT and lateral X- ray images of the patient s larynx for correct insertion of needles. However, the risks associated with posterior dissection of the thyroid cartilage in standard AA, such as perforation of the piriform sinus, bleeding, or edema of the larynx, might be much greater than those associated with radiation exposure during CT/X-ray imaging. In general, AA surgery applied to correct the vocal fold level and medialization thyroplasty, such as type I thyroplasty, are concurrently performed for insufficient glottic closure of a highly atrophic vocal fold or a widely opened anterior glottic chink. 6,14 In the 10 cases described, we used several methods, endoscopic AA surgery alone or a combination of AA surgery and type I thyroplasty or fat injection laryngoplasty, based on the each patient s condition or the movement of the vocal fold observed by laryngeal endoscopy. All cases demonstrated dramatic improvements in MPT, MFR, acoustic parameters, and the patient s perception of his or her own voice. Although the mean MPT before the operation was 4.3 seconds, the postoperative mean MPT was improved to 14.1 seconds. Eight of 10 patients achieved MFR values of less than 200 ml/second after surgery. The mean values of shimmer and jitter were significantly improved after the operation. It is important to 1279

7 evaluate patients perceptions of their condition. We examined the patients perceptions of their own voices and the improvement in their quality of life postoperatively. All of the patients were satisfied with their voices and our procedure. Unfortunately, we did not evaluate them using an objective index such as the voice handicap index. Finally, these results suggest the validity and utility of our novel EAAS method. CONCLUSION We have demonstrated the principle behind and operative procedure for our novel EAAS technique. Our phonation analysis data indicate the efficacy of EAAS. Preoperative evaluation of the position of the MP on CT/ X-rays of the larynx and the use of several helpful devices during surgery helped to increase the proportion of correct insertions. EAAS can be used in combination with medialization laryngoplasty as a novel AA surgical option for UVFP. BIBLIOGRAPHY 1. Isshiki N, Tanabe M, Sawada M. Arytenoid adduction for unilateral vocal cord paralysis. Arch Otolaryngol Head Neck Surg 1978;104: Tokashiki R, Hiramatsu H, Tsukahara K, et al. A fenestration approach for arytenoid adduction through the thyroid ala combined with type I thyroplasty. Laryngoscope 2007;117: Abraham MT, Gonen M, Kraus DH. Complications of type I thyroplasty and arytenoid adduction. Laryngoscope 2001;111: Ejnell H, Mansson I, Bake B, Hallen O, Stenborg R, Lindstrom J. A simple operation for bilateral vocal cord paralysis. Laryngoscope 1984;94: Umeno H, Chitose S, Sato K, Nakashima T. Efficacy of additional injection laryngoplasty after framework surgery. Ann Otol Rhinol Laryngol 2008; 117: Friedrich G, de Jong F, Mahieu HF, Benninger MS, Isshiki N. Laryngeal framework surgery: a proposal for classification and nomenclature by the Phonosurgery Committee of the European Laryngological Society. Eur Arch Otorhinolaryngol 2001;258: Netterville JL, Stone RE, Civantos FJ, Luken ES, Ossoff RH. Silastic medialization and arytenoid adduction: The Vanderbilt experience. A review of 116 phonosurgical procedures. Ann Otol Rhinol Laryngol 1993;102: Kraus DH, Orlikoff RF, Rizk SS, Rosenberg DB. Arytenoid adduction as an adjunct to type I thyroplasty for unilateral vocal cord paralysis. Head Neck 1999;21: Maragos NE. The posterior thyroplasty window: Anatomical considerations. Laryngoscope 1999;109: Koufman JA, Isaacson G. Laryngoplastic phonosurgery. Otolaryngol Clin North Am 1991;24: Jin SM, Park CY, Lee JK, Ban JH, Lee SH, Lee KC. Transcutaneous injection laryngoplasty through the cricothyroid space in the sitting position: anatomical information and technique. Eur Arch Otorhinolaryngol 2008; 265: Mitchell JR, McRae BR, Halum SL. Localization of the muscular process for arytenoid adduction surgery. Laryngoscope 2009;119: DeLegge MH. Percutaneous endoscopic gastrostomy. Am J Gastroenterol 2007;102: Nito T, Ushio M, Kimura M, Yamaguchi T, Tayama N. Analyses of risk factors for postoperative airway compromise following arytenoid adduction. Acta Otolaryngol 2008;128: