Type I: Physiological Sulcus

The sulcus affects only the epithelium and the SLP. Gross anatomical inspection may reveal a slight divot in the mucosa as well as a spindle-shaped glottal configuration during adduction. This minor deviation in the mucosa is believed to be congenital and is not always considered pathological.

Type II: Sulcus Vergeture

This pathological sulcus is characterized by an anterior-posterior groove between the upper and lower margins of the vocal fold. In this case, the SLP is significantly involved or even absent, with the epithelium tethered directly to the vocal ligament. Increased collagen deposits surround this focal lesion, creating a stiff, non-vibrating band along the medial edge of the vocal fold. This band affects vocal fold closure (resulting in a spindle-shaped glottal configuration) and mucosal wave propagation.

Type III: Sulcus Vocalis

The third sulcus type is the most severe , involving the full depth of the vocal fold. The epithelium folds into the LP with the deepest portion of the invagination tethered directly to the vocalis muscle. Collagen fibers are present in the LP surrounding the sulcus. The lumen of the pocket formed is lined with stratified epithelial cells that become more keratinized as they approach the vocalis muscle. Some hypothesize that these deep sulci are actually ruptured or open epidermoid cysts [32]. These sulci are often challenging to appreciate upon indirect endoscopic evaluation, but palpation of the region during direct laryngoscopy will reveal the groove. The complete absence of the SLP and vocal ligament as well as the increase in collagen deposits surrounding the sulcus can be appreciated functionally using stroboscopy, as the non-vibrating segment around the sulcus has a significantly reduced or absent mucosal wave (Fig. 30.2).

Case History

Children and adolescents who present with chronic vocal fold scarring frequently have extensive and complex medical histories. Individuals at particular risk for developing vocal fold scar include those with a history of JORRP [36, 37], prolonged intubation and/or upper airway reconstruction [38, 39], laryngeal web [40, 41], mass lesions involving the vocal ligament [35], and—while rare—laryngeal cancer [42–45]. When obtaining a case history, clinicians should assess the onset, duration, and current presentation of vocal complaints; daily voice use and vocal behaviors; and quality of life and academic impact of the vocal complaint. In addition to these standard questions, it is also important to obtain a thorough medical history. Many of these patients may present with active concomitant disease processes at the time of evaluation that may take precedence over treatment of poor vocal function. Therefore, as part of the case history, it is essential to evaluate not only the patient’s current medical status but also the patient’s and caregivers’ readiness and ability to pursue voice treatment.

Perceptual, Acoustic, and Aerodynamic Assessments

The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) [46, 47] and dysphonia grade, roughness, breathiness, asthenia, and strain (GRBAS) [48] scales are perceptual assessments conducted by a certified speech language pathologist that should be included in a comprehensive evaluation. Voice quality for patients with vocal fold sulcus or scarring (informed by findings from adult studies) is typically characterized by harsh voice, diplophonia, and abnormal pitch or volume; however, it has also been reported that patients with vocal fold sulcus may instead present with breathy voice due to incomplete glottal closure [35]. Patients with either disorder may complain of increased effort or vocal fatigue. Acoustic and aerodynamic data for patients with vocal fold scarring in the pediatric population are limited; however, based upon our understanding of the structural changes associated with vocal fold scar or sulcus, elevated perturbation measures of jitter and shimmer, and decreased harmonic to noise ratio would be expected. Fundamental frequency may be abnormal for age and gender due to changes in tissue mass, and airflow measures would be expected to be abnormal due to increased subglottal pressure and potentially incomplete glottal closure.

Laryngeal Imaging

Otolaryngologists visualize the gross anatomy and function of the larynx during a laryngoscopy using a flexible endoscope. The goal is to evaluate structural anomalies including irregular vocal fold edge (Fig. 30.3) and identify concomitant factors such as laryngopharyngeal reflux or chronic inflammation related to allergies or other disease processes which may contribute to, or exacerbate, vocal fold scarring. Laryngologists or speech pathologists will also conduct a videostroboscopic or high-speed videoendoscopic assessment of vocal fold vibration using either a rigid endoscope or distal-chip flexible endoscope. Although videostroboscopy is the current gold standard for functional assessment, challenging cases may benefit from high-speed videoendoscopy for improved temporal resolution of vocal fold vibration [49]. During the laryngeal imaging assessment, clinicians evaluate vibratory function for amplitude, mucosal wave, and glottal closure patterns. Deviations in these characteristics may range from mild to severe. The hallmark feature of scarring is a non-vibratory or adynamic segment visualized as reduced, asymmetric, or absent amplitude and mucosal wave. Visualization of the scarred region may be intermittent and brief (particularly if located along the inferior medial aspect of the vocal fold) and therefore challenging to appreciate [50]. Additional attention should be given to characterize any negative compensatory strategies that have been developed to manage disordered vibratory function.

Minimizing Risk

Since vocal fold scarring is a common sequela following intervention for other, more serious disorders of the larynx and upper airway, the surgical team must often balance the competing goals of maintaining or restoring the airway (intubation and/or airway reconstruction) and optimizing voice outcomes [38]. With this challenge in mind, one of the most effective approaches for reducing the effect of chronic vocal fold scarring is to take a conservative approach when treating other structural disorders which may ultimately result in scarring. Many of the recommendations for conservative treatment are borrowed from the adult population; however, they serve as valuable guidance for treating the pediatric population as well.

JORRP is the second most common cause of hoarseness among children and adolescents [37]. The nature of the JORRP disease process necessitates multiple surgical interventions to remove lesions from the vocal folds to maintain an adequate airway, and the management of JORRP depends on the degree of airway involvement. Recommended treatment options include surgical removal using laser, cold instrumentation, or microdebrider as well as potential use of adjuvant pharmacological therapies. To minimize the risk of vocal fold scarring, only diseased tissue should be removed, and the underlying lamina propria should be preserved as much as possible [51].

Prolonged intubation in medically fragile neonates and children also represents a significant risk factor for developing chronic vocal fold scar and/or laryngeal stenosis. Scarring may be caused by acute trauma to the vocal folds and posterior larynx during intubation. Long-term placement of an endotracheal tube may also cause irritation to the posterior larynx, as pressure from the wall of the tube against the posterior larynx can obstruct blood flow, delaying wound healing [39, 52]. Selection of the appropriate endotracheal tube materials and tube size is critical to reducing the risk of developing chronic scarring [53]. It is recommended that the tube with the minimum outer diameter necessary to maintain adequate ventilation should be used [39, 52, 53]. Benjamin further describes the composition for an ideal endotracheal tube for prolonged intubation. Specifically, it should be made of nontoxic, synthetic materials which are smooth enough to prevent irritation and have thermoplastic properties which allow it to conform to the tissue contours at body temperature. Additionally, both the tube walls and cuff should allow for a wide pressure distribution to minimize focal contact pressures [39]. As scar formation and possible posterior laryngeal stenosis may develop days to weeks following extubation, one could consider performing serial flexible laryngoscopies if injury was seen on prior exams or there was concern for injury based on post-extubation dysphonia or airway restriction symptoms [38, 39].

Laryngeal webbing may also present as a secondary sequela to prolonged intubation or surgical intervention, particularly when the mucosa is disrupted bilaterally, allowing web formation. Congenital laryngeal webbing has also been reported but is considered to be rare [40]. Clinical presentation ranges from asymptomatic to severe dysphonia with respiratory compromise. In mild cases, surgical intervention may not be warranted, as further disruption of the mucosa may increase the risk of additional scarring [54].

Voice Therapy

Despite implementation of adequate precautions, laryngeal scarring may be unavoidable. Voice therapy is an appropriate initial, noninvasive intervention for treatment of vocal fold scar. While voice therapy may not be completely effective in recovering premorbid vocal function, early intervention by a speech language pathologist is critical for developing optimal voice behaviors and preventing the development of negative compensatory strategies [38, 55, 56]. Therapeutic techniques should focus on improving tissue pliability while eliminating laryngeal tension or supraglottic compression. Attention to deficits in the respiratory and resonance systems may further improve overall system function. The voice therapy trajectory is highly dependent on the severity of the scar, the resources and ability of the family to support therapy, and patient buy-in and compliance. Clinical reports suggest that as the child matures, awareness of their voice disorder and subsequent readiness for change increase. Thus, some patients may pursue therapy years after the initial scar development, and clinical reports indicate that therapy is still beneficial despite scar maturation [55]. Patients who do not see acceptable improvement with voice therapy alone may receive benefit from surgical intervention.

Medical Intervention

There is little consensus on the optimal medical or surgical intervention for vocal fold scarring. Temporary therapeutic options for adults include collagen [57] or fat injectables [58–61] used primarily to increase tissue volume and improve glottal closure. Given the dynamic nature of laryngeal development in the pediatric population, temporary interventions such as injectables may be a first line of approach to mitigate symptoms. More invasive treatment approaches include microcauterization, repeated dilation of the glottis (particularly for webbing), and microflap elevation to release adhesions [38, 62]. Depending on the severity of the fibrosis, introducing a series of vertical incisions across the length of the sulcus or scar may improve voice quality. This technique, developed by Pontes and Behlau, releases the contracted tissue to improve pliability [39, 63]. Despite the seemingly traumatic nature of this treatment, positive outcomes have been reported [63]. Regardless of the type of intervention, care must be taken to prevent additional scarring due to surgical technique; if the mucosa is exposed bilaterally, placement of a laryngeal keel or other temporary prosthesis is recommended to separate the divided tissues and prevent additional scarring or web formation [54].