DISCUSSION
Contact granuloma, also called larynx contact ulcer or vocal process granuloma4. It is reported that the incidence of the contact ulcer is approximately 0.9%-2.7% in voice disorders5. It is more common in man than woman, more precisely, man suffer 2~9 times large than woman among the disease6 . The lesions usually appear in unilateral vocal folds and sometimes bilateral vocal folds, and typically in term of nodularation and epithelial ulceration of varying degrees. The diagnosis of granuloma is very easy, generally based on symptoms and laryngoscopy without biopsy, which is different from laryngeal cancer. Pathologically, contact granuloma is not true granuloma that because of lacking in cluster of mononuclear and multinucleated histiocytes. They usually manifested as infiltration of inflammation cells, capillary proliferation and fibrosis, and sometimes as epithelial hyperplasia and perichondrium keratosis7.According to a grading system by Farwell et al8, clinical manifestations of the patient may be asymptomatic or have varying degrees of voice disturbance, throat edema, and varying levels of laryngeal discomfort and breathing difficulties.
Contact granuloma is always considered idiopathic when the common causes like laryngopharyngeal reflux and anesthesia intubation are eliminated, and some other causes are no-good habits of voice like incorrect phonation and habitual throat clearing. That’s to say, The mechanical irritation caused by bilateral vocal fold collision and the inflammation caused by gastric acid reflux cause direct damage to the vocal fold mucosa9. meanwhile, Smoking, inflammation, allergic reaction, postnasal drip and social psychological pressure are also important inducing factors of granuloma10. Only a few patients can determine the reasons through application of reflux symptom index and reflux finding score, and pharyngo-oesophageal 24-h pH monitoring. The complexity of the causes makes the treatment difficult and controversial. The current treatment for LCG mainly includes voice correction, medication, surgical treatment and vocal fold injection. Empirically, voice therapy and PPI is its first-line treatment11. During the treatment cycle, patients are instructed to silence their voices, try to avoid unconscious throat clearing and coughing, and change incorrect phonation. At the same time, patients need to improve their lifestyles to reduce laryngopharyngeal reflux, including losing weight, reducing the amount of meals, and avoiding lying down within 3 hours after eating, adhering to a low-fat and low-acid diet, and avoiding intake carbonated or caffeinated beverages and spicy stimulation food.
PPI are effciency in contact granuloma even though the patient do not combined with laryngopharyngeal reflux12. However, the treatment cycle of internal medicine is very long, and the average treatment period is about 4.7 months13. Some patients may experience gastrointestinal disorders such as diarrhea, nausea, abdominal pain, or lack of gastric motility such as flatulence and constipation or other symptoms. The recurrence rate up to 12.12% when recurrent patient received PPI, and 3% even though combined with injection corticosteroids into granuloma14.
Surgical treatment is usually considered in the case of drug treatment failure or recurrence granuloma. Surgical removal were not recommended by some researchers because of it can shrink the size of the granuloma in the short term but has high rate of recurrence in the long term11. An recent study indicate that The initial non-surgical treatment (67 percent) has a much higher cure rate than surgical treatment (30 percent) in contact granuloma patients9. Jingyi Wu reported that given postoperative radiotherapy within 24 hours can reduce the recurrence of laryngeal granuloma effectively15. Vojko Djukic have studied that Zinc supplementation for the treatment of granuloma of the larynx is one of the conservative treatment16. Zinc affects the healing process of wounds though the exact mechanism is unclear.
From Q Pham, botulinum toxin A injection threaten the powerful collision and adduction of posterior portion larynx via relaxing lateral cricoarytenoid muscle17. The collision of bilateral arytenoid cartilage can cause local cartilage inflammation, mucosal ulcers, and granulation tissue hyperplasia. Therefore, botulinum toxin A injection can temporarily act on the denervated vocal fold muscles, reducing the strong collision of the bilateral vocal folds and promoting the repair of the vocal fold mucosa. The team’s previous research showed that surgery combined withbotulinum toxin A injection is highly effective in voice disorders18. A series of studies also show that botulinum toxin A injection is safe and effective in the treatment of LCG17,19. Botulinum toxin A injection broaden the structure of the granuloma strategy from a chemical point of view for the first time and transfer to innervated muscles and can be alternative therapy under patients’ choice and institution’s situation or applied to the failure on voice therapy or PPI 17,20.
The recurrence and refractory of LCG has always been the clinical focus of attention of otolaryngologists. Regardless of the surgery strategy, CO2 laser, angiolytic potassium titanyl phosphate laser or cold instrument resection, it is difficult to achieve the desired effect in the operation to remove the lesion alone. In this study, the pedicled mucosal flap of ventricular band was transferred to the wound after laser resection of granuloma, and the mucosa was anastomosed by microsurgery. This is an update of the traditional operation of Ni Xin et al21and solves the problem that the released mucosal margin of the wound cannot completely cover the fresh wound, which may resulting in easy recurrence. In this study, no matter the size of granulomatous wound, we can take the pedicled mucosal flap to completely close the wound, which eliminates the potential pathological basis of granulomatous inflammation and achieves the purpose of one-time basic cure. The acquisition and transfer of mucosal flap follows the principle of voice surgery, staying in as a superficial plane as possible and preserving the normal mucosa. It not only completely excises the lesion, but also limits the lesion wound to the root of granuloma, and completely reconstructs the cover-body of vocal fold (epithelium plus superficial lamina propria), which is conducive to the recovery of vocal fold mucosal wave and the prevention of local scar or stenosis. At the same time, assisted microsurgery can avoid mucosal avulsion and displacement, accelerate fibrosis of the mucosal flap wound and granuloma wound. Secondly, the choice and acquisition of mucosal flap is minimally invasive, easy to obtain and survive, which avoids open surgical trauma and increases the survival rate of mucosal flap. Recently, the combined treatment of vocal fold granuloma has significantly improved the efficiency compared with the single treatment, and has gradually become a trend 14,13, 22. This method combined with botulinum toxin A injection reserve a time window for the recovery of mucosal flap, also help to correct the phonation model and stabilize the surgical effect. Postoperative PPI therapy is an important step to consolidate the curative effect, control potential gastric acid reflux and avoid recurrence. It can be seen that the concept of combined treatment of LCG retains the advantages of various treatment methods, which is of great significance for the thorough treatment of the disease, and is an undeniable trend in the treatment of contact granuloma.
Precision operability with great patience and caution is needed in the surgery. The width of the pedicle should not be less than half of its length in theory, so that the flap can survive. When suturing, the surgeon should pay attention to the position of the needle and the control of the wrist strength, the tension should be appropriate, the torsion or fenestration of the pedicle of the microflap should be prevented from necrosis of the mucosa, and the fully mucosal coverage of the surgical wound is the key to the success of the operation. Furthermore, experienced anesthesiologists will use a smaller diameter endotracheal tube to expose the surgical field more clearly. At the same time, when the glottis is exposed by endotracheal intubation, surface anesthesia will be combined to reduce the fluctuation of vital signs and hemodynamics during the operation.
After standardized medical treatment and voice correction for 3 months, there was no significant improvement in refractory LCG. It was suggested that local pedicled mucosal flap transfer combined with botulinum toxin A injection should be performed. As a preliminary study, there were no systemic or local complications, high cure rate and low recurrence rate. The cure of the disease also inspired the treatment of vocal fold scar, adhesion, laryngeal stenosis, etc. we will continue to further clinical observation and including more patients.