Vocal cord paralysis is a rather common problem causing speech problems to the patient. If the other cord doesn’t compensate adequately these patients may have troublesome aspiration also. Aspiration happens to be the most dreaded complication of vocal fold paralysis. Management of these patients is possible only by performing Medialization thyroplasty (Ishiki type I thyroplasty). Various graft materials have been used in this procedure. Presently lot of interest has been generated in Gor-Tex medicalization thyroplasty.
Advantages of Gor-Tex:
Gor-Tex is expanded polytetrafluroethylene has obvious advantages as an implant material in Medialization thyroplasty procedures.
1. It is malleable
2. Its position can easily be adjusted within the thyroid cartilage window
3. Only a small fenestration is necessary in the lamina of thyroid cartilage to introduce this material
4. This procedure is reversible and has very few complications
5. Creates less oedema when compared to that of silastic and hence over correction is not possible
6. Resultant quality of voice is really good
Hoffman and McCullouch reported the first case of medialization thyroplasty using Gor-Tex in May 1996.
Indications of Gor-Tex Medialization thyroplasty:
1. Unilateral vocal fold immobility due to paralysis, paresis, atrophy
2. Unilateral vocal fold scarring / soft tissue loss
3. In select cases of Parkinson’s disease with vocal fold atrophy
Contraindications of Gor-Tex thyroplasty:
1. Previous history of irradiation
2. Malignant lesions involving larynx
3. Poor abduction of contralateral vocal fold as this would cause impairment of airway
This procedure is ideally performed under local infiltration anesthesia using 2% xylocaine mixed with 1 in 100,000 units’ adrenaline.
Horizontal skin crease incision beginning at the mid portion of the thyroid cartilage extending to the paralyzed side.
The strap muscles are separated away from midline and held apart from the operating field using umbilical tape.
A tracheal hook is used at the level of laryngeal prominence and pulled medially. This helps in mobilizing the cartilage better.
The thyroid cartilage perichondrium is incised in the midline and extended laterally towards the paralyzed side. The thyroid lamina on the paralyzed side is skeletonized up to the level of cricothyroid membrane. Strips of cricothyoid muscle that come in the way are excised.
Dimensions of cartilage cuts:
Appropriate size of cartilage window is about 5mm x 10mm. The lower border of the window should be about 3mm above cricothyroid membrane. This ensures that the lower strut of thyroid lamina doesn’t fracture when window is being created. Anterior border of the window is about 8mm posterior to midline. If thyroid cartilage is calcified then fissure burr can be used to create the window.
The inner perichondrium is elevated from the under surface of thyroid lamina using scissors. The inner perichondrium incised posteriorly and inferiorly. It is not incised anteriorly. Now the cricothyroid membrane is incised in order to separate it from the lower border of thyroid cartilage. A septal elevator is introduced through the inferior margin of thyroid lamina and the paraglottic space is compressed medially while the voice of the patient is assessed. If the result is acceptable then 1 cm wide Gor-Tex strips dipped in bacitracin solution is introduced via the inferior margin of thyroid lamina and delivered via the window. The amount of Gor-Tex insertion is dependent on the improvement of quality of voice.
If necessary use prolene sutures passing via the inferior strut of thyroid lamina to stabilize Gor-Tex. Wound is closed in layers after keeping a penrose drain.
It is very important to perform pre operative and post operative video laryngeal examination.