Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, U.S.A
Send correspondence to Seth H. Dailey, MD, Division of Otolaryngology–Head and Neck Surgery, Department of Surgery, University of Wisconsin School of Medicine and Public Health, K4/760 Clinical Science Center, Madison, WI, 53792-7395. E-mail: firstname.lastname@example.org
Numerous original and successful techniques have built the armamentarium of options for displacing and augmenting vocal folds when the vocal folds meet incompletely.[1, 2] Voice results and surgical options retain meaningful limitations, however.[3-5] Implanted materials are exogenous, such as titanium, or autologous, such as fat. They can be prone to migration, allergic reaction, and extrusion. They may require a harvest site separate from the larynx. Also, they may not be durable long-term; exogenous injectables are resorbed, and injected autologous fat or fascia lacks a blood supply to maintain its survival. To help solve this dilemma, experimental work using human cadaveric larynges and an in-vivo canine model was performed to assess the safety and feasibility of the application of a novel vascularized soft tissue flap for reconstruction of the vocal fold. The Composite Thyroid Ala Perichondrium Flap (CTAP) incorporates fat from the preepiglottic space pedicled on vascularized perichodrium from the thyroid ala. The first two human cases of unilateral CTAP use are presented here.
MATERIALS AND METHODS
After Institutional Review Board approval, the charts of the two individuals undergoing CTAP placement for correction of glottic defects were accessed, and patient demographics, history, and outcomes recorded.
A 52-year-old woman presented with dysphonia following unilateral left vocal fold Teflon injection 15 years prior for idiopathic left vocal fold paralysis. Stroboscopic exam revealed an immobile left hemilarynx with convexity of the musculomembranous vocal fold, and total loss of mucosal wave with inflammatory change of the overlying epithelium. After informed consent was obtained, she underwent open removal of the Teflon through a thyroplasty type I window, and subsequent elevation and delivery of a laterally based CTAP into the defect to prevent lateralization of her vocal fold (“empty paraglottic space syndrome”).
Intravenous sedation and local anesthesia were delivered as during a standard thyroplasty. After standard exposure of the larynx for thyroplasty, an ipsilateral laterally based CTAP was outlined and elevated (Fig. 1), as described previously. A thyroplasty type I window was outlined and removed using an oscillating saw as, also as described previously. The Teflon of the paraglottic space was removed, leaving a convex vocal fold. The CTAP was delivered through the window into the paraglottic space defect and secured with Vicryl sutures (Fig. 2). Vocal feedback was solicited from the patient during placement of the CTAP to help assure optimal voice outcome. The wound was closed in layers over a passive drain.
A 70-year-old man presented with dysphonia following an open partial cordectomy for a right-sided T2N0M0 squamous cell carcinoma 7 years prior. Evaluation revealed a contracted right vocal fold with no mucosal wave, as well as a severely dysplastic lesion of the left vocal fold. After informed consent was obtained, he underwent right vocal fold reconstruction with a CTAP for restoration of glottic competence and 532 nm-pulsed KTP laser angiolysis for the dysplastic lesion.
Suspension microlaryngoscopy was performed permitting 0 degree telescopic views of the glottis to be projected onto a video monitor. The identical neck incision was used, as in case 1. A right-sided inferiorly based CTAP was outlined and elevated (Fig. 3). An oscillating saw was used to remove a 6 mm × 6 mm window of cartilage, with its medial edge 2 mm off of midline, and its superior edge at the level of the superior margin of the vocal folds—as determined by a 27-gauge “finder” needle. Custom-made dilators (Instrumentarium, Montreal, Canada) designed by the senior author (S.H.D.) were used over a guidewire to develop a plane immediately deep to the vocal fold epithelium for creation of a tunnel into which the CTAP was placed (Fig. 2).The contracted right vocal fold was noted to be smooth and straight following inset of the flap into the scarred lamina propria of the right vocal fold (Fig. 4). The wound was closed in layers over a passive drain. 532 nm KTP laser treatment of the left vocal fold dysplastic lesion was performed and the patient extubated.
There were no surgical complications, including wound, swallowing, or airway concerns. Neither patient has pursued additional reconstructive options for improvement of voice.
Follow-up time is 22 months for patient 1 and 11 months for patient 2. Voice measures are displayed in Table 1 and Table 2. Notable improvements in MPT and pitch range are present in case 1. Notable improvements in all parameters are present in case 2.
Table 1. Voice Results for Case 1 at Noted Timepoints for Available Outcome Measures.
RANGE denotes the frequency range (Hz).
GRBAS = grade of dysphonia (G), roughness (R), breathiness (B), asthenia (A), and strain (S); LVS = laryngovideostroboscopy; CLOSURE denotes the degree of vocal fold closure during a sustained /i/. JITTER denotes the percent Jitter (%). MPT = maximum phonation time (s).
Table 2. Voice Results for Case 2 at Noted Timepoints for Available Outcome Measures.
GFI denotes glottal function index. CLOSURE denotes the degree of vocal fold closure during a sustained /i/. JITTER denotes the percent Jitter (%). RANGE denotes the frequency range (Hz); SYMMETRY denotes the degree of symmetry of vocal fold oscillation during a sustained /i/.
AR = aerodynamic resistance (cm H20/L/s); CNA = could not assess; DSI = Dysphonia Severity Index; GRBAS = grade of dysphonia (G), roughness (R), breathiness (B), asthenia (A), and strain (S); IA3-QOL = Iowa voice assessment-quality of life; IA3-VQ = Iowa voice assessment-voice quality; LVS = laryngovideostroboscopy; MPT = maximum phonation time (s); PTP = phonation threshold pressure (cm H20); VHI = Vocal Handicap index.
Could not assess
The general notion of glottic function restoration is new neither for cases of Teflon granuloma nor for glottic defects following cancer surgery.[7-10] However, the lack of acceptance of a more standardized technique for reconstruction of a glottic defect relates to the ongoing limitation of glottic reconstructive substances. The stimulus for conceiving the CTAP was derived from the successes and limitations of previously implemented materials. An ideal surgical implant for the vocal fold must have the following characteristics: low-cost, avoid a separate harvest site, resist rejection, and require a minimally invasive approach. Plus it must be effective in voice improvement, tailorable to a glottic defect, applied to one or both vocal folds, and durable. Finally, it must exert minimal morbidity on the patient, and have physical properties that may be malleable with additional biologic adjustments.
The CTAP is an attempt to satisfy these requirements. As it is derived from the patient's larynx, there is no additional cost for an exogenous material. As it is derived from the surgical field for standard thyroplasty, there is no separate harvest site. Since it is autologous, there is no risk of rejection. Since it utilizes similar skill sets to standard laryngoplasty, it is no more invasive than modern techniques. Since CTAP can have substantial volume when harvested, it is therefore tailorable to larger or smaller defects, if desired. Furthermore, the CTAP can be placed, as demonstrated by these two cases, either laterally within the paraglottic space or superficially to reconstruct lamina propria defects. An inferiorly based CTAP allows for bilateral flap harvest and therefore use in one or both vocal folds. Since it carries its own blood supply, it is likely, although not yet proven, to be durable. Since it is derived from a noncritical region of the larynx in the preepiglottic space, it is likely to exert minimal morbidity on the patient provided that the surgeon avoids injury to the internal branch of the superior laryngeal nerve. Since CTAP is composed of adipose tissue, which contains adult-derived stem cells, and since the aerodynamic shear stress of phonation will exert an effect on the cells (a.k.a., a bioreactor), it is possible that morphologic and therefore functional change to the tissue may occur over time, with a resulting adaptation of the flap to the local environment. Particularly attractive is the possibility of favorable effects on a scarred environment by local adipose secretory factors, as noted in wrinkling.
Limitations to this study and approach exist and are acknowledged. Only two cases are reported and the longest follow-up date is 22 months postoperatively. Longer term follow-up is required to establish equivalence or superiority to established techniques, perhaps using fine-cut CT to evaluate persistence of the flap. Also, formal voice measures will be helpful for comparison to other techniques. The approach may be viewed as complex. However, the only novel element is the harvest of the flap since minithyrotomy and thyroplasty approaches have existed for one and three decades, respectively. Notably this reconstructive option might be difficult to reverse, but it could be revised endoscopically in the case of overcorrection or contour irregularity and does not “burn bridges” for additional reconstructive options. If the approach is to be used for vocal fold scar, then technical difficulty will always exist when developing the superficial tunnel. The custom dilators used here are similar in concept to the Marechal dilators used in the treatment of salivary duct pathology and may not be superior. Successful dilation relies on the distensibility of the surrounding tissue and risks perforation of the overlying epithelium, putting any implanted tissue at risk for extrusion or infection from secretions. Paniello et al. have suggested placement of free perichondrium to patch the epithelial rent in such a case. Potential solutions include the use of sialendoscopy instruments, whether for sharp dissection as with scissors or blunt dissection as with microballoons. High speed rotation of microdebrider tips has also been reported for dissection in Reinke's space.
These first two reported cases of CTAP application represent the translational movement of a new surgical technique into use for correction of glottic insufficiency. There were no operative complications or morbidity, and both standard and novel instrumentation were easily applied. CTAP was used successfully for correction of both a paraglottic space and a superficial vocal fold defect with improvement of voice in both individuals. Use under both sedation and general anesthesia were successful. These early successes suggest that further use of CTAP for correction of typical and atypical glottic defects of the lamina propria or vocal fold musculature may be promising.
Thanks to Dr. Nathan V. Welham for assisting in image management.