Sulcus vocalis and its management
Vocal fold cleft, vocal fold scarring.
Sulcus vocalis is caused by migration of the vocal fold epithelium in to the normally convex lamina propria, causing a cleft in the vocal fold. The presence of this cleft alters the way vocal folds osscilate causing voice changes.
Classification of sulcus vocalis:
Ford etal classified sulcus vocalis into three types: In all these types the cleft is present on the medial surface of the vocal fold. Ford Type I: Here the longitudinal depression of the vocal fold epithelium extends into the lamina propria, but does not reach the vocal ligament. This depression extends often along the full length of the vocal cord. This sulcus is commonly present and cause only a mild vocal dysfunction. Hence it is often termed as physiologic sulcus.
Ford Type II: The sulcus extends throughout the full length of the vocal cord. The depression extends upto the vocal ligament, there is also an associated loss of lamina propria. This anamoly causes a disruption of the mucosal wave pattern which is responsible for normal voice production.
Ford Type III: Here the sulcus is deep and focal in nature giving the apprearance of a pit. The whole length of the cord is not involved. There is also an associated loss of lamina propria. This type of defect causes a disruption of the mucosal wave. Histology of these lesions show diffuse fibrosis, neovascularisation and inflammation.
Etiopathogenesis of sulcus vocalis (Theories):
As usual congenital and acquired theories have been postulated to explain the etiopathogenesis of sulcus vocalis.
Arnold Bouchayer theory:
This theory attributes a congenital cause to explain the etiopathogenesis of sulcus vocalis. This theory postulates a faulty genesis of the 4th and 6th branchial arches as the cause for sulcus vocalis. Epidermoid cysts present in the vocal fold due to this faulty genesis of 4th and 6th arches are believed to rupture causing this disorder. Genetically, in these patinets vocal fold scars are characterised by replacement of the normal micro architecture by disorganised collagen causing a reduction in the volume of vocal fold thus making it less pliable to vibrations during speech.
The following factors favour this theory:
1. Appearance in childhood.
2. Not known to recur after surgery.
3. Familial propensity.
Microscopically these lesions are characterised by the presence of:
Van Canegham's theory:
attributes this condition to be acquired in nature. Trauma and mycobaterial infections have been implicated as probable causes for this condition. In fact a significant amount of sulcus vocalis has been found in the opposite vocal cord when the ipsilateral vocal cord is affected by malignant lesion. This lends credence to this theory.
Recent authors have accepted both these theories as probable cause of sulcus vocalis.
Patients will complain of chronic hoarseness of voice, vocal insufficiency and loss of quality of voice. Indirect laryngoscopy and direct laryngoscopic examinations will demonstrate the presence of sulcus vocalis in the free margin of the vocal folds. On video stroboscopy loss of mucosal wave in the affected portions of the vocal folds will be clearly appreciated.
The goal in managing this problem is to improve the glottic efficiency, reduce strain to the vocal folds, and improvement in the overall voice quality.
1. Patient must be advised adequate voice rest.
2. Speech therapy and speech councelling should be attempted.
3. GERD if present must be aggressively treated.
4. Rhinosinusitis if present must be treated
Multiple surgical techniques have been formulated for treatment of sulcus vocalis. Before prceeding with surgical management one aspect should be clearly assessed: the ability of the surgeon to visualise the full length of the vocal cord endoscopically. If such clear visualisation is not possible then medialisation thyroplasty or injection thyroplasty or voice therapy may be resorted to.
This technique is used to close the glottic gaps commonly seen in sulcus vocalis. This procedure cannot be performed endoscopically. This is an external procedure which uses different medialising implants like silastic, Gore-tex or hydroxyapatite blocks. Sometimes strap muscles can also be used is autogenous graft is preferred. Goretex is the preferred material to medialise the vocal fold. This material not only reduces the glottic gap it also maintains the normal pliability of the vocal folds. The surgical procedure will be detailed elsewhere.
Collagen can be injected into the vocal fold thereby causing medialisation of the injected vocal fold. This procedure can be preformed through an endoscopic approach. This injection can be performed under out patient settings. This injection closes the glottic gap causing an improvement in the quality of voice. The only problem with this method is that collagen has been known to be absorbed by tissues. No long term study is available to study the long term effects of this injection. Large gaps cannot be treated by this method.
This procedure is performed under microlaryngeal approach. It involves a longitudinal epithelial cordotomy with release of the sulcus from its depth followed by simple redraping of the epithelium. The major advantage of this procedure is that implants need not be used and is a fairly simple procedure to perform. The release of the tethered tissue helps to close the glottic chink somewhat better. One major word of caution is that the healing process of the epithelial cover is not under our control, ultimately the operated area may heal with fibrosis reducing the pliability of the vocal fold whereby worsening the condition. Surgery must hence be performed with utmost caution with minimal trauma to the covering mucosa.
Laser undermining with redraping: CO2 laser is used lto perform the cordotomy. It has the advantage of excellent hemostasis with minimal trauma to the surrounding tissues. Steroids are injected at the time of redraping and fibrin glue is applied to the epithelium to facilitate reapproximation and tissue healing of the epithelial cover.
Slicing technique of Pontes and Behlau:
This technique utilises the principles of scar contracture repair. The scar bands are interrupted with medial advancem ent of vocal fold cover. In this procedure cuts of varying lengths are made in the coronal plane of the vocal fold to release the longitudinal scar band. This procedure is reserved for cases of severe deformities where less aggressive surgical management may not suffice.
Glottic insufficiencies can be corrected by injecting fat into the paraglottic space. This can be achieved via a laryngofissure approach.