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Chin Med J (Taipei) 1997;59:254-8.
Department of Otolaryngology, Veterans General Hospital-Taipei; and National Yang-Ming University, Taipei, Taiwan, R.O.C.
Background. Vocal fold cyst is a common cause of dysphonia. In our reported series, most cases were retention cysts. Enucleation of the cyst under microlaryngoscopy is usually considered to be an ideal treatment despite the fact that cyst rupture is frequently encountered with this procedure. In this report, we present a wide opening method for vocal fold retention cyst.
Methods. Twenty consecutive patients with vocal fold retention cysts larger than 2 mm in diameter were operated upon using the wide opening method (marsupialization). The medial cyst wall was excised along with the overlying mucosa, while the lateral cyst wall was preserved on the vocal fold. The cyst was widely opened following this procedure.
Results. Perceptual voice improvement was noted postoperatively. Videostroboscopy and acoustic analysis were also applied to confirm the perceptual results.
Conclusions. The wide opening method has the advantages of simplicity, minimal tissue injury, rapid functional recovery and low recurrence. This technique can be considered another standard treatment of choice for medium- or large-sized vocal fold retention cysts.
[Chin Med J (Taipei) 1997;59:254-8.]
Keywords: vocal fold cyst, wide opening method
Received: September 7, 1996.
Accepted: January 10, 1997.
Address reprint requests to: Shyue-Yih Chang, MD, Department of Otolaryngology, Veterans General Hospital-Taipei, 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan, R.O.C.
Vocal fold cyst is a common cause of dysphonia. It is usually located in various parts of the submucosal Reinke's space of the vocal fold. Since the pliability of Reinke's space intimately influences mucosal wave propagation and voice quality, vocal fold cysts not only result in incomplete vibratory closure of the vocal fold, but also hinder mucosal wave propagation during phonation [1]. According to Monday's reports, vocal fold cysts are classified into two major groups: epidermoid cysts and retention cysts [2,3]. In our series, most cases were retention cysts which could have been a result of mucous glandular duct obstruction.
Surgical enucleation has been the standard treatment for vocal fold cysts [4]. However, the retention cyst wall, composed of only one to three layers of epithelial cells (Figure 1), ruptures easily during the procedure and incomplete cyst wall removal and recurrence may consequently occur. Significant neighboring tissue injury and vocal ligament exposure are other complications which can occur when complete removal of the ruptured cyst wall is attempted. To prevent the poor wound healing and unsatisfactory voice improvement which can often result [1], a wide opening method, simple in procedure and rarely mentioned in the literature, is herein proposed to try to eliminate some of the problems encountered with enucleation.
Twenty consecutive cases (8 male and 12 female, aged 18-73 years) of vocal fold retention cyst larger than 2 mm in diameter were operated upon with the wide opening method (Table 1). Most patients (15/20) used their voices in a professional capacity. The main complaint was dysphonia, lasting from one month to over 10 years, especially after vigorous vocal activity.
In this surgery, location of the cyst was first delineated under microlaryngoscopy. Dilated vessels, if noticed, were cauterized to minimize surgical bleeding. A small incision was then made on the mediolateral midpoint of the upper cyst wall and the content removed by suction. The outer part of the cyst wall, along with the overlying vocal fold mucosa, was everted and excised. The wound was then delicately trimmed with microsurgical instruments. A concavity on the vocal fold was the final appearance immediately after surgery. This was the preserved lateral cyst wall right above the vocal ligament. The actual surgical wound existed only at the junction of the marginal rim of the concavity and the surrounding mucosa (Figures 2,3).
Phoniatric evaluation was conducted before and two weeks after the operation. The tests employed were perceptual evaluation, videostroboscopy and acoustic analysis. Perceptual evaluation was done by a laryngologist and a speech pathologist, grading the severity of hoarseness from 0 to 3. The acoustic analysis of the voice recordings was carried out with CSL (Computerized Speech Labs, model 4300, Kay Elementric Corp.). Jitter, shimmer, and harmonics-to-noise ratio were calculated by computer after extracting two seconds arbitrarily from the spectrogram of a sustained vowel /a/ produced at a habitual, comfortable pitch and loudness. The analysis was repeated three times for each recording.
Among the 20 patients, nine had concomitant vocal fold disorders, including vocal sulcus and vocal nodule. Bilateral vocal fold cysts were noted in one patient (Table 1). The vocal nodule was also removed during the surgery. Two weeks after the operation, improved glottic closure was noted under videostroboscopy, except in two patients with obvious concomitant vocal sulcus. The concavity noticed immediately after the operation had almost disappeared, but some degree of mucosal congestion was found on the vocal fold. Mucosal wave propagation at the lesion site was nearly normal. No recurrence was found in the consecutive follow-up over the next six months and 18 of the patients had perceptual improvement in the severity of hoarseness. Both patients who failed to show improvement in perceptual evaluation had concomitant vocal sulcus (Figure 4).
In acoustic analysis, jitter and shimmer generally decreased postoperatively while harmonics-to-noise ratio tended to increase. These findings were comparable with the improvement in perceptual results (Figure 5).
Since the introduction of layered microstructure of the vocal fold by Dr. Hirano [4], the principle of endolaryngeal surgery has been widely accepted as a method for removing laryngeal lesions with as little surrounding normal tissue injury as possible. However, cyst rupture is frequently encountered during this procedure, partly because of the thinness of the cyst wall and partly because adhesion of the cyst wall to the overlying mucosa is often significant. In most cases, it is difficult to enucleate the cyst completely without cyst rupture, loss of mucosa or vocal ligament exposure. Recurrence may result from incomplete enucleation, whereas excessive vocal fold damage may result if complete cyst wall removal is attempted, as demonstrated in our report [1]. Enucleation, although ideal, is not applicable in practical terms, especially for many medium- or large-sized vocal fold retention cysts (>2 mm in diameter).
The pathogenesis of retention cysts can be obstruction of the mucous gland ducts, usually caused by inflammatory or traumatic processes [3,5-7]. With the presented technique, the cysts can be widely opened so that there is no more ductal obstruction or retention of secretion and recurrence is minimized. Although the mucosa overlying the medial cyst wall was excised in the procedure, the vocal ligament was still protected by the lateral cyst wall, with a minimal surgical wound located right at its junction with the vocal fold mucosa. The temporary concavity observed immediately after this operation was the result of the pliable Reinke's space being compressed by the cyst (Figures 2D,3). In the following two postoperative weeks, this concavity almost disappeared after eliminating the cause of compression since most retention cysts rarely invade the vocal ligament. We believe the preserved lateral cyst wall might take the place of the mucosa, since mucosal wave propagation returned to nearly normal at the lesion site under postoperative videostroboscopy. Eradication of the pathologic condition was thus achieved with minimal normal tissue injury. Whether the cuboidal cyst wall undergoes further histological changes on the vocal fold is still an unknown issue of interest, since there is no animal model for vocal fold surgery [8]. Results for the first six months following surgery were satisfactory, but long term follow-up is required to see if our reported method of surgery is producing consistent favorable results.
The wide opening method is technically simple and ordinary microsurgical instruments are adequate for the procedure. Cysts smaller than 2 mm in diameter were not selected in our series, owing to limitations imposed by the size of the instruments, and submucosal enucleation was suggested for this situation. Two patients with concomitant vocal sulcus showed no obvious perceptual improvement. One of them was a case of recurrent vocal fold cyst operated on two years earlier at another hospital and the other had severe hyperfunctional dysphonia. Therefore, the final voice outcome may be flawed by concomitant functional and organic disorders, which should be treated at the same time.
Although acoustic analysis revealed general improvement, many variations and exceptions were noted in our study. Human voice production is a highly complex procedure affected by laryngeal, articulatory and respiratory functions. The acoustic indices we used may reflect only a small part of voice production. Patients' motivation, temporary emotional status, previous practice and instruction also greatly affect the stability of each parameter. Further investigations with more attentive study designs and more parameters are required to obtain more information upon voice disorder through acoustic analysis.
Although it is difficult to objectively compare the results of different surgical techniques for vocal fold retention cysts, marsupialization can be an effective method, yielding results which are as satisfactory as enucleation. With the advantages of simplicity, high applicability, minimal tissue injury and low recurrence, it can be regarded as another standard treatment of choice for medium- or large-sized vocal fold retention cysts.
Copyright: 1997, Chinese Medical Association (Taipei)