Preservation of function and histologic appearance in the injured glottis with topical mitomycin-C

A randomized trial of topical mitomycin-C in the immediate post-operative period for the short and long-term prevention of granulation tissue in mastoid cavities

BACKGROUND

Granulation tissue is a primary source of otorrhea in the ear, particularly after surgery, and may develop complications in patients. Hence, discovering an efficient treatment is crucial for this disorder.

PURPOSE

This study aimed to evaluate the mitomycin drops efficacy for germination prevention during the recovery process after mastoidectomy. Our purpose was to introduce novel treatment options in some conditions in which we could not reconstitute the cavity to prevent the possible germination.

MATERIALS AND METHODS

This clinical trial was performed on 52 patients undergoing mastoidectomy. Patients were randomly divided into two groups (26 patients in the mitomycin group and 26 patients in the placebo group). After drug administration, the granulation tissue and complications were recorded. All statistical analysis was performed using SPSS version 21.

RESULTS

The results of our study showed that mitomycin administration in patients undergoing mastoidectomy significantly reduced the formation of the granulation tissue in the first and third months after surgery (P < 0.05), which is associated with increased patient satisfaction (P < 0.05).

CONCLUSION

The germ formation after mastoidectomy is so common. Since mitomycin administration decreased the incidence of germ formation, it can be proposed as a suggestive treatment in all patients to increase surgical quality and decrease complications include granulation formation.

The Effects of Rapamycin on the Proliferation, Migration, and Apoptosis of Human Tracheal Fibroblasts (HTrF) and Human Tracheal Epithelial Cells (HTEpiC)

Background: Restenosis after airway stenting needs to be addressed urgently. Rapamycin has been proven to inhibit restenosis elsewhere. This study aimed at observing its effects on the respiratory tract. Methods: CCK-8, wound healing, Transwell and apoptosis assays were performed to detect the effects of rapamycin on the survival, migration, and apoptosis, respectively, of human tracheal fibroblasts (HTrF) and human tracheal epithelial cells (HTEpiC). Results: The effective concentrations of paclitaxel, mitomycin C and rapamycin on HTrF were 10⁻⁷–10⁻⁴ mol/L, 10⁻⁶–10⁻⁴ mol/L, and 10⁻⁵–10⁻⁴ mol/L, respectively. At the effective concentrations, the inhibition rates of paclitaxel on HTEpiC were (43.03 ± 1.12)%, (49.49 ± 0.86)%, (55.22 ± 1.43)%, and (93.19 ± 0.45)%; the inhibition rates of mitomycin C on HTEpiC were (88.11 ± 0.69)%, (93.82 ± 0.96)%, and (94.94 ± 0.54)%; the inhibition rates of rapamycin on HTEpiC were (10.19 ± 0.35)% and (94.55 ± 0.71)%. At the concentration of (1–4) × 10⁻⁵ mol/L, the inhibition rate of rapamycin on HTrF was more than 50%, and that on HTEpiC was less than 20% (p < 0.05). Conclusions: Compared to paclitaxel and mitomycin C, rapamycin had the least effect on HTEpiC while effectively inhibiting HTrF. The optimum concentration range was (1–4) × 10⁻⁵ mol/L.

[Endoscopic treatment of bronchial complications after lung transplantation]

OBJECTIVE

To analyze the incidence and structure of bronchial complications following lung transplantation and evaluate an effectiveness of endoscopic treatment of these events.

MATERIAL AND METHODS

The study enrolled 50 patients after bilateral lung transplantation (24 men and 26 women). Mean age of patients was 35.4±5 (19; 61) years. Ischemia of bronchial mucous membrane of the transplant was intraoperatively and postoperatively analyzed. We also assessed severity and prevalence of anastomotic and non-anastomotic cicatricial bronchial stenoses.

RESULTS

All patients after lung transplantation were diagnosed with bronchial complications, i.e. ischemia of bronchial mucous membrane of the transplant. In 76% of patients, these complications did not require endoscopic treatment. Surgical and endoscopic treatment was required in 24% of cases. Three patients (6%) underwent intraoperative correction of bronchial anastomosis. Bronchial suture failure was diagnosed in 3 patients (6%), cicatricial bronchial stenosis - in 6 (12%) cases. Endoscopic stenting was effective for recovery of bronchial patency with complete epithelialization of mucous membrane. Stenting of lobar bronchus with application of mitomycin C was effective in patients with non-anastomotic stenoses type III after lung transplantation.

CONCLUSION

Major bronchial complications occurred in 24% of patients after lung transplantation. Endoscopic treatment of bronchial complications using a self-fixing silicone endoprosthesis after lung transplantation was effective in all patients with anastomotic and non-anastomotic cicatricial strictures. Mitomycin C prevented excessive growth of granulation and scar tissue.

Subglottic Stenosis in Children: Preliminary Experience from a Tertiary Care Hospital

INTRODUCTION

This retrospective study describes our experience in the evaluation and management of infants with subglottic stenosis.

MATERIALS AND METHODS

The study included 10 patients aged between 1 wk and 18 months with 6 cases having congenital subglottic stenosis and 4 cases having acquired subglottic stenosis.

RESULTS

6 patients had grade I, 3 patients had grade II, and 1 patient had grade III subglottic stenosis. Tracheostomy was required in 4 patients at the time of presentation. 7 patients were treated successfully with Bougie dilation followed by topical application of mitomycin, whereas 1 patient who failed to serial dilation needed open reconstructive procedure. Laser excision of the anterior subglottic web was performed in one patient. Another patient with underlying cerebral palsy could not be operated upon and was managed with tracheostomy.

CONCLUSION

Subglottic stenosis may be effectively man-aged with endoscopic surgical techniques, although the number of such sittings required varies with the type and severity of stenosis. Open surgical procedures need to be individualised as per the needs of the patient only after all the other endoscopic possibilities have been exhausted.

Mitomycin C in the endoscopic treatment of tracheal stenosis: a prospective cohort study

Objective:

To evaluate the efficacy of mitomycin C (MMC) in the endoscopic treatment of tracheal stenosis.

Methods:

Patients with laryngotracheal, tracheal, or tracheobronchial stenosis were treated with dilation and topical MMC. The inclusion criteria were as follows: being ineligible for surgery (for medical reasons) at the time of evaluation; membranous stenosis responding well to dilation; and postoperative stenosis at the anastomosis site. Etiology of stenosis and indication for treatment with MMC, as well as site, length, and percentage of stenosis, together with presence of tracheostomy and duration of follow-up, were analyzed. The outcomes evaluated were symptom-free interval ≥ 12 months, number of dilations with topical application of MMC, and complications.

Results:

Twenty-two patients (15 men and 7 women) were treated between 2003 and 2010. Stenosis was due to endotracheal intubation in 15 patients and surgery in 8. Pure tracheal stenosis was encountered in 13 patients, subglottic stenosis was encountered in 4, tracheobronchial stenosis was encountered in 3, and complex stenosis was encountered in 2. The length of stenosis ranged from 0.5 cm to 2.5 cm, and the percentage of stenosis ranged from 40% to 100%. Nine patients had undergone tracheostomy and had a Montgomery T-tube in situ. Treatment was successful in 14 patients, who remained free of symptoms for at least 12 months. The number of topical applications of MMC ranged from 1 to 5, and complications included fungal infection, keloid scarring, granuloma, and mediastinal emphysema.

Conclusions:

MMC appears to be effective in the endoscopic treatment of tracheal stenosis.

Contact Diode Laser Myringotomy and Mitomycin C in Children

OBJECTIVE: To investigate the use of contact diode laser myringotomy (C-LAM), combined with topical mitomycin C, as an alternative method for prolonged middle ear ventilation in children with otitis media with effusion.

STUDY DESIGN AND SETTING: Prospective study at a tertiary care pediatric institution.

METHODS: Fifteen children enrolled in the study. Mitomycin C was applied to the intact tympanic membrane in the right ears, whereas saline on the left side was used for controls. C-LAM was then performed in all ears. Outcome measures included healing rate and scarring, ear infection, and long-term audiometric follow-up.

RESULTS: There was no significant difference in median healing rate. In each group, the median was between the third and fourth month. Normal hearing thresholds were obtained in all children at 2-year follow-up.

CONCLUSION: C-LAM proved to be an effective method for medium-term ventilation, but topical mitomycin C before C-LAM did not prolong patency rate in our patients. No significant complication was encountered at 2-year follow-up. (Otolaryngol Head Neck Surg 2004;130:742-6.)

Prevention of Posterior Glottic Stenosis by Mitomycin C

Objectives:

Posterior glottic stenosis (PGS) is a disabling disease commonly induced by endolaryngeal injury from intubation or surgery. Few experiments on PGS prevention, however, have been performed. The purpose of this study was to investigate the preventive effect of mitomycin C (MMC) on PGS in a randomized, controlled animal study.

Methods:

Twenty-six rabbits underwent laser injury of 6 W, continuous-focus mode on the posterior glottis. There were 6 uninjured controls. Thirteen animals were treated by a single topical use of 0.4 mg/mL MMC solution on the injured posterior glottis for 5 minutes, and 13 were sham-treated controls. The posterior glottis of all groups was blindly evaluated by telescopic examination under direct laryngoscopy 2 months after injury and was harvested for histologic analyses.

Results:

Scar, granulation tissue, and synechia formation of the posterior glottis were clearly induced by laser injury. Microscopic examination showed increased collagen content and fibroblast proliferation in the region. The use of MMC significantly decreased the incidence of such gross and microscopic changes of the posterior glottis (p < .05).

Conclusions:

This study suggests that topical MMC can be helpful in preventing the progression of PGS from mucosal injury of the posterior glottis.

Foresight in Laryngology and Laryngeal Surgery: A 2020 Vision

Laryngology and laryngeal surgery have been in the vanguard of minimally invasive human procedural interventions for approximately 150 years. The natural passages through the oral cavity, nose, and pharynx have provided an accessible gateway to the larynx that has allowed for rapid translation of a variety of diagnostic and therapeutic technologies. Transoral and transcervical laryngeal surgery have been further facilitated by progressive advancements in local, topical, intravenous, and general anesthesia. With rapid developments in engineering disciplines (ie, tissue, chemical, mechanical) and voice science, there are a variety of current and near-term opportunities to advance our field. This report represents a panel at the 2005 American Broncho-Esophagological Association meeting that sought to use present perspectives, combined with cutting-edge research insights, to provide foresight into key aspects of laryngology that we believe will be developed by the year 2020. We hope that aspiring laryngeal surgeons will find elements of this discussion valuable for devising a strategic roadmap for research initiatives in laryngology and laryngeal surgery.

Mitomycin C Effect on Fibrous Adhesions of Rabbit Temporomandibular Joint

OBJECTIVE: To evaluate influence of mitomycin C on fibrosis in temporomandibular joints of rabbits with mandibular traction.

STUDY DESIGN: Twenty rabbits (8 control, 12 mitomycin C group) were included. Titanium screws were placed in the anterior edge of the right masseter tuberosity and the posterior part of the right zygoma. Elastic bands were placed between 2 screws to initiate posterio-superior displacement of the mandible to the right. Animals in the control group (CG) received intraarticular NaCl (0.9%) on the nondrawing (left) side, and animals in the study group (SG) received mitomycin C weekly (0.4 mg/mL) for 6 weeks. Rabbits were decapitated, temporomandibular joints were removed, and histopathological investigation was performed.

RESULTS: Microscopically, 4 of 6 rabbits in the CG had fibrosis in the temporomandibular joint, whereas only 1 of 11 rabbits in the SG had fibrosis ( P < 0.05).

CONCLUSION: Application of mitomycin C to the temporomandibular joint of rabbits significantly reduces formation of intraarticular fibrous adhesions.

SIGNIFICANCE: This is the first study in the literature investigating the use of mitomycin C in the joints.

The Effects of Intradermal and Topical Mitomycin C on Wound Healing

OBJECTIVE: To determine the effect of intradermal and topical mitomycin C (MMC) on skin wound healing.

STUDY DESIGN/SETTING: A prospective, controlled study in a rat wound model performed in an academic medical center.

RESULTS: Intradermal and topical MMC application decreased wound integrity when compared with saline-treated animals at 1 week, 2 weeks, 1 month, and 6 months. Skin necrosis occurred in animals that received intradermal MMC. Hemotoxylin and eosin and immunohistochemical staining showed no consistent difference between treatment arms. Fibrosis and collagen deposition were reduced in MMC-treated wounds on trichrome staining.

CONCLUSIONS: MMC-treated wounds showed decreased wound strength compared with controls. Intradermal MMC can cause skin necrosis. Histologic findings did not always correspond with clinical data.

SIGNIFICANCE: The data suggest cautious use of MMC in clinical situations when wound breaking strength is critical.

Analysis of therapeutic methods for treating vocal process granulomas

CONCLUSION

The combination of laryngeal microsurgery and local injections of botulinum toxin type A (BTA) can increase the cure rate of patients with vocal process granulomas (VPGs).

OBJECTIVE

To analyze the therapeutic effects of conservative treatments, microsurgical resection with suturing and microsurgery in combination with local injections of BTA for the treatment of VPGs.

METHODS

A retrospective analysis of 168 cases of VPG was performed. All of the patients initially received a conservative treatment. Some of the patients who did not respond to the conservative treatments were treated using microsurgical resection and microsuturing using an 8-0 absorbable filament. Other patients additionally received a four-point injection of BTA into the thyroarytenoid muscle and the arytenoid muscle on the operated side.

RESULTS

The lesions of 41.3% (71/168) of the patients who were given the conservative treatments (including acid suppression, vocal rest, and voice therapy) disappeared, and the lesions of 10.7% (18/168) of the patients were reduced. The conservative treatments were unsuccessful for 47% (79/168) of the patients. The cure rate was 78.4% (29/37) for the patients who were treated by microscope resection using a CO2 laser and microsuturing of the surrounding mucosa. Of the eight patients who experienced a recurrence, five of them had lesions that disappeared after 3 months of conservative treatment, whereas the other three patients recovered after a second operation. The cure rate of the 42 patients who were treated using microsurgery combined with local injections of BTA was 95.2% (40/42), with only 2 cases of recurrence at 2 months post-treatment.

Dose-dependent effect of mitomycin C on human vocal fold fibroblasts

BACKGROUND

The purpose of this study was to evaluate in vitro cytotoxicity and antifibrotic effects of mitomycin C on normal and scarred human vocal fold fibroblasts.

METHODS

Fibroblasts were subjected to mitomycin C treatment at 0.2, 0.5, or 1 mg/mL, or serum control. Cytotoxicity, immunocytochemistry, and Western blot for collagen I/III were performed at days 0, 1, 3, and 5.

RESULTS

Significant decreases in live cells were measured for mitomycin C-treated cells on days 3 and 5 for all doses. Extracellular staining of collagen I/III was observed in mitomycin C-treated cells across all doses and times. Extracellular staining suggests apoptosis with necrosis, compromising the integrity of cell membranes and release of cytosolic proteins into the extracellular environment. Western blot indicates inhibition of collagen at all doses except 0.2 mg/mL at day 1.

CONCLUSION

A total of 0.2 mg/mL mitomycin C may provide initial and transient stimulation of collagen for necessary repair to damaged tissue without the long-term risk of fibrosis.

Endoscopic cold incision, balloon dilation, mitomycin C application, and steroid injection for adult laryngotracheal stenosis

OBJECTIVES/HYPOTHESIS

To describe the presentation, stenosis characteristics, etiological differences, and outcomes of adult laryngotracheal stenosis treated with endoscopic cold incision, balloon dilation, topical mitomycin C application, and steroid injection.

STUDY DESIGN

Retrospective chart review.

METHODS

Demographic and clinical data were extracted for patients treated between March 2000 and December 2010. Prolonged intubation and idiopathic patient data were utilized for comparative analysis.

RESULTS

Eighty patients (65 females; 15 males; 220 procedures; 2.9 years mean follow-up) presented with dyspnea (81%) and/or exercise intolerance (40%). Most commonly, etiologies were idiopathic (53 of 80; 66%) or prolonged intubation (14 of 80; 18%). Mean procedures per patient and interval between procedures were 2.8 procedures and 405 days, respectively. Mean stenosis length and distance from the caudal phonating edge of the true vocal folds were 9 mm and 19 mm. Complication, tracheotomy, and open-procedure rates were 1.8%, 1.4%, and 10.0%, respectively. Patients with more than two procedures demonstrated a mean 4-mm reduction in stenosis length and a 2-mm cephalad progression of stenosis over time. More caudal stenoses required more frequent procedures. Procedures were less frequent as more procedures were performed. Stenosis characteristics, interval between procedures, and total procedures were similar between idiopathic patients with or without intubation histories, but different between idiopathic and prolonged intubation patients.

CONCLUSIONS

This procedure was shown to be a viable option in adult laryngotracheal stenosis. Repeat dilation was likely, but was performed without adversely affecting stenosis characteristics. Stenoses farther from the vocal folds required procedures more frequently. Idiopathic patients with a history of brief, elective intubation had stenosis characteristics and responses to therapy similar to idiopathic patients without an intubation history. Both idiopathic groups together demonstrated stenosis characteristics and responses to therapy dissimilar to patients with a history of prolonged intubation.

Arytenoid and posterior vocal fold surgery for bilateral vocal fold immobility

PURPOSE OF REVIEW

Many procedures exist to address the airway restriction often seen with bilateral vocal fold immobility. We review the most recent studies involving arytenoid and/or posterior vocal fold surgery to provide an update on the issues related to these procedures. Specific focus is placed on selection of the surgical approach and operative side, use of adjunctive therapies, and outcome measures including decannulation rate, revision and complication rate, and postoperative results.

RECENT FINDINGS

Ten studies were identified between 2004 and 2011. Modifications to the orginal transverse cordotomy and medial arytenoidectomy techniques continue to be investigated to seek improvement in dyspnea symptoms with minimal decline in voice and/or swallowing function. Decannulation rates for these approaches are high. Postoperative dysphagia appears to be less commonly observed but requires continued study. The use of mitomycin-C in these procedures has been poorly studied to date.

SUMMARY

Both transverse cordotomy and medial arytenoidectomy procedures result in high success rates. However, many questions related to these procedures remain unanswered, particularly with respect to preoperative and postoperative evaluations of voice quality, swallowing function, and pulmonary status. There is need for rigorous prospective clinical studies to address these many issues further.

Endoscopic treatment of glottic stenosis: a report on the safety and efficacy of CO2 laser

Background:

Treatment of glottic stenosis is a considerable challenge to the otolaryngologist. Glottic airway patency can be compromised by bilateral vocal fold palsy, anterior webbing or a posterior segment scar, which may be significant enough to impair arytenoid movement.

Method:

A retrospective analysis of a prospective database of patients (n = 34) treated by a specialist airway surgeon. All patients underwent endoscopic treatment with a CO2 laser in an attempt to improve airway calibre and, in 12 patients, to decannulate tracheostomy tubes.

Results:

Twenty-one patients had bilateral vocal fold palsy and 13 had predominantly posterior glottic stenosis. A variety of pathology-directed treatment approaches were used to achieve good functional results. Four patients required a second endoscopic procedure. The overall revision rate was 5 per cent for bilateral fold palsy and 23 per cent for posterior glottic stenosis (p < 0.05). All patients had an adequate functional airway calibre, and all 12 tracheotomised patients were decannulated.

Discussion:

Pathology-directed endoscopic laser surgery is safe and effective treatment for glottic stenosis. Rather prescriptive use of unilateral or bilateral cordotomy or combined cordo-arytenoidectomy, clinicians must perform the procedure that will treat the lesion most adequately. Our success rate compared favourably with the best reported results.

Effect of mitomycin-C on post-operative adhesions in tendon surgery: an experimental study in rats

We investigated the effect of mitomycin-C on the reduction of the formation of peritendinous fibrous adhesions after tendon repair. In 20 Wistar albino rats the tendo Achillis was cut and repaired using a modified Kessler technique. The rats were divided into two equal groups. In group 1, an injection of mitomycin-C was placed between the tendon and skin of the right leg. In group 2, an identical volume of sterile normal saline was injected on the left side in a similar fashion. All the rats received mitomycin-C or saline for four weeks starting from the day of operation. The animals were killed after 30 days. The formation of peritendinous fibrous tissue, the inflammatory reaction and tendon healing were evaluated. The tensile strength of the repaired tendons was measured biomechanically. Microscopic evidence of the formation of adhesions and inflammation was less in group 1. There was no significant difference in the tensile load required to rupture the repaired tendons in the two groups. Mitomycin-C may therefore provide a simple and inexpensive means of preventing of post-operative adhesions.

[Bronchoscopic dilation techniques and topical application of mitomycin-C in the treatment of tracheal stenosis post intubation - two case reports]

Tracheal stenosis follows any injury to the airway mucosa, such as ischaemic, traumatic and other injuries. The treatment of tracheal stenosis remains a challenging problem despite all the advances in endoscopic and surgical techniques. Scar formation and reestenosis are the main causes of treatment failure. The authors present two cases of successful treatment of a tracheal stenosis after tracheal injury from prolonged oro -tracheal intubation / tracheostomy following dilatation with rigid broncoscope and laser therapy, associated with topical application of mitomycin C as an adjuvant treatment.

Topical use of MMC in the upper aerodigestive tract: a review on the side effects

Not much is known about the side effects of mitomycin C (MMC), an anti-fibrogenetic agent, in the upper aerodigestive tract. However, its use in ophthalmology is widely known and without quantitatively important side effects. A literature review was performed for side effects of MMC in the upper aerodigestive tract. Forty-six articles, describing the use of MMC to prevent scarring, were retracted from PubMed. Thirty-two are human studies. MMC is used in different concentrations (0.1–10 mg/ml) with different application times (2–5 min) and frequencies (up to 4 times). Five hundred and thirty-eight patients were included in those publications, of whom 19 developed side effects (3.53%). No side effects developed in studies, where post-application irrigation with saline was reported. The longest mean follow-up period is 75.5 months. Direct relations between the reported side effects and MMC seem absent in most studies. Serious complications seem to occur when MMC is used in high concentrations. Unfortunately, sometimes crucial information is lacking. One patient was described who supposedly developed laryngeal carcinoma after repeated treatment of hyperkeratosis and anterior commissure webbing. Animal studies show that excessive fibrin production can lead to acute airway obstruction. In conclusion, topical application of MMC on a wound with consecutive irrigation with saline can be performed safely to prevent scar formation in circular structures of the upper aerodigestive tract. Long-term yearly control of the application site seems advisable.

The butterfly procedure: a new technique and review of the literature for treating anterior laryngeal webs

Congenital laryngeal webs, subglottic stenosis, and laryngeal atresia result from various degrees of failure of airway recanalization as a spectrum. The symptoms also range from asymptomatic to dysphonia and severe airway obstruction. There are a number of methods for management of symptomatic patients. In this article, we discuss a new procedure that was used in the management of two anterior laryngeal web patients with relatively acceptable results.

Efeito da mitomicina-C tópica sobre os depósitos de colágeno total na submucosa das pregas vocais íntegras de suínos

OBJETIVO: Estudar o efeito da aplicação tópica de Mitomicina-C em diferentes concentrações sobre os depósitos de colágeno total na submucosa de pregas vocais íntegras de suínos. MÉTODOS: Os animais foram divididos em três grupos de acordo com o conteúdo da solução tópica aplicada sobre as pregas vocais: solução fisiológica 0,9 % (grupo controle); Mitomicina-C tópica 4 mg/mL (grupo 1); e Mitomicina-C 8 mg/mL (Grupo 2). Após 30 dias da aplicação, os animais foram submetidos à eutanásia, coletado amostras das pregas vocais e coradas pela técnica do picrosirius red com polarização para a quantificação computadorizada da deposição do colágeno, através do programa Image Pro plus 4.5Ò. Compararam-se as médias de área do colágeno depositado na submucosa das pregas vocais dos três grupos através do teste não paramétrico de Mann-Whitney. RESULTADOS: As médias das áreas de depósito colágeno na submucosa das pregas vocais foram de 3.110,44 micrômetros quadrados (mm²); 3.115,98 mm² e 3.105,78 mm² nos grupos controle, 1 e 2 respectivamente. Não houve diferença significativa nas áreas de depósitos de colágeno total da submucosa das pregas vocais entre os três grupos estudados (p>0,05). CONCLUSÃO: A mitomicina-C aplicada topicamente em pregas vocais suínas íntegras não alterou significativamente a deposição de colágeno na submucosa.

Comparative study in swines' vocal cords healing after excision of fragment with CO2 laser with mitomycin and 5-fluorouracil postoperative topical application

PURPOSE: To evaluate the deposition of collagen fibers at pig's vocal folds after topical use of mitomycin or 5-fluorouracil, when partial exeresis of mucosa layer had been promoted by CO2 laser. METHODS: There were used 18 Larger white pigs which were anesthetized and submitted to mucosa fragment's exeresis, bilaterally, at its free border. The animals were divided into 3 groups, each one with 6 animals: control group, without topical drug application; mitomycin group; and 5-fluorouracil group. After 30 days, the animals were subjected to euthanasia, and samples of the vocal folds were collected and stained by picrosirius red technique with polarization for quantification of total collagen deposition. RESULTS: In control group, the mean rate of right vocal fold's collagen deposition at submucosa consisted in a 3428.66 micrometers area. There was found an area whose size had, in average, 2196.36 micrometers, in mitomycin group, and 2269.19 micrometers, in 5-fluorouracil group. CONCLUSION: Mitomycin and 5-fluorouracil had promoted beneficial change in vocal fold's cicatrization with less collagen deposition, but there was no significant statistically difference when they were compared between themselves.

Study of wound healing in rats treated with topical and injected mitomycin-C

Experimental study in animals. Introduction: Mitomycin C has been used as a fibroblasts inhibitor, thus reducing the scaring process in surgical wounds.

Aim

This paper aims at assessing the use of Mitomycin C to reduce the scaring process through its topical use and later injected reinforcements.

Materials and Methods

We used a model of a creating a wound in the dorsum of rats, removing a circular piece of skin and letting it heal by itself. We used 18 rats, divided in three groups. The first group - Control, the second with topical use, and a third group with injected mitomycin C reinforcement, monthly for 2 months. After 3 months the animals were slaughtered and the scars were surgically removed and sent for histology study.

Results

We noticed, under different criteria, that healing with topical mitomycin is less intense; however, when it was injected, the parameters were again comparable to those from the control group.

Discussion

We believe that injected mitomycin C in the scar, since it is highly toxic, it destroys tissue and brings about scar neoformation.

Conclusions

Mitomycin C reduces the scaring process when used topically; however, it increases scar tissue formation when injected in these wounds.

Study of Wound Healing in Rats Treated with Topical and Injected Mitomycin C

Objectives:

Mitomycin C, a widely used chemotherapeutic drug, has been proposed as a potential adjuvant for the control of scar tissue in surgical wounds because of its capacity to inhibit fibroblast proliferation. The current study used a combination of topical and injected mitomycin C to slow the healing process of surgical wounds in rats.

Methods:

An experimental model of surgical wounding at the dorsum of rats was used. A total of 43 animals were subdivided into 3 groups: Control, topical mitomycin C, and a combination of topical treatment and intradermal injections of the drug at 30 and 60 days after the initial topical treatment. After 3 months, the animals were painlessly sacrificed and the surgical scars were removed for microscopic analysis.

Results:

The group that received only topical mitomycin C presented milder inflammatory signs and consequently had a less intense healing process than the control group. The group treated with a combination of both topical and injected mitomycin C presented results comparable to those of the control group.

Conclusions:

The toxic characteristics of mitomycin C were most likely responsible for the greater tissue damage that occurred when it was used in the injected form, causing increased scar tissue formation. Mitomycin C slows the healing process of surgical wounds when used topically, but causes enhanced scar tissue formation when injected.

Histopathologic changes in guinea pig mastoid mucosa after topical mitomycin C application followed by mastoidectomy

PURPOSE

This study was performed to investigate the histopathologic changes observed in mastoid cavity of guinea pigs after the application of mitomycin C after mastoidectomy.

MATERIALS AND METHODS

The study was performed on 50 guinea pigs. Unilateral (right ear) mastoidectomy was performed on all guinea pigs. Twenty-five guinea pigs were separated as study group and the remaining were separated as control group. A mitomycin C-soaked sponge was placed in the mastoid cavities of the study group and a dry sponge was placed in those of the control group. Their mastoid cavities were examined histopathologically for absorbable sponge waste, abscess formation, fibrosis, vascularization, polymorphonuclear leukocyte infiltration, edema, lymphoplasmacytic inflammatory infiltration, and granulation tissue.

RESULTS

Absorbable sponge waste, abscess formation, fibrosis, vascularization, edema, and lymphoplasmacytic inflammatory infiltration were not significantly different between the groups. However, polymorphonuclear leukocyte infiltration and granulation tissue were statistically different between the groups.

CONCLUSION

Mitomycin C can be used after mastoidectomy to decrease the granulation tissue formation in ear discharges and to prevent the discharge.

Mitomycin C and airway surgery: How well does it work?

Objective

Systematically review and critically evaluate all available published data on the use of topical mitomycin C (MMC) as an adjunctive in airway surgery.

Data Sources

Published studies indexed in MEDLINE, EMBASE, or Cochrane databases. Inclusion criteria were English language, sample size greater than five, and publication of data applicable to the analysis of topical MMC and airway surgery outcomes.

Review Methods

Evidence tables were compiled to include sample size, study design, and evidence level. Summary statistics, random-effects modeling, and subgroup analysis were performed.

Results

Twenty manuscripts (eight human, 12 animal) met the inclusion criteria. Seven of eight (87.5%) of the human studies and eight of 12 (66%) animal studies concluded topical MMC was beneficial to airway surgical outcomes. Eleven of twelve animal studies included randomization and a control group, compared with only two of eight human studies. Random-effects modeling of human studies (k=7) indicated that 81.4 percent (95% CI, 72.0%-90.9%; P < 0.001) of patients had improved outcomes attributable to MMC. Random-effects modeling of animal data included modeling of change in airway diameter (Hedge's G = −0.03; 95% CI, −0.66-0.60; P = 0.924) and the change in histologic measures (Hedge's G = 1.26; 95% CI, 0.596-1.92; P < 0.001) in MMC-treated animals vs controls.

Conclusion

The majority of the published literature individually suggests the use of topical MMC improves airway surgery outcomes. However, heterogeneity within the clinical studies, the lack of controlled data, and the lack of significance in the pooled animal data (other than histologic outcomes) suggest that the utility of MMC is still undetermined.

Foresight in laryngology and laryngeal surgery: a 2020 vision

Laryngology and laryngeal surgery have been in the vanguard of minimally invasive human procedural interventions for approximately 150 years. The natural passages through the oral cavity, nose, and pharynx have provided an accessible gateway to the larynx that has allowed for rapid translation of a variety of diagnostic and therapeutic technologies. Transoral and transcervical laryngeal surgery have been further facilitated by progressive advancements in local, topical, intravenous, and general anesthesia. With rapid developments in engineering disciplines (ie, tissue, chemical, mechanical) and voice science, there are a variety of current and near-term opportunities to advance our field. This report represents a panel at the 2005 American Broncho-Esophagological Association meeting that sought to use present perspectives, combined with cutting-edge research insights, to provide foresight into key aspects of laryngology that we believe will be developed by the year 2020. We hope that aspiring laryngeal surgeons will find elements of this discussion valuable for devising a strategic roadmap for research initiatives in laryngology and laryngeal surgery.

Topical mitomycin C effect on swine vocal folds healing

Several adjuvant therapies to surgery have been used to modulate the healing process of vocal folds, including topic mitomycin (MTC).

Aim

to evaluate the effect of topical MTC in the healing process of vocal folds 30 days after the exeresis of a mucosal fragment with CO₂ laser in a swine model (control group without mitomycin and study group with topical MTC), with collagen deposition measurement.

Study type

prospective experimental in swine.

Methods

two groups of 6 swine each were subjected to exeresis of a mucosal fragment of the vocal fold with CO₂ laser. Immediately after the procedure MTC was applied topically for three minutes on the study group. Thirty days later the animals were slaughtered and samples of the vocal folds were collected for histological analysis, with the purpose of quantifying collagen deposition by Picrosirius Red stain.

Results

the average area of total collagen in the vocal folds in the control group was 2.648,03 µm2, whereas in the study group it was 2.200,30 µm2 (p = 0.0043).

Conclusion

topical application of MTC after the exeresis of a mucous fragment of vocal fold with CO₂ laser in swine significantly decreased total collagen deposition.

Defining phonosurgery: a proposal for classification and nomenclature by the Phonosurgery Committee of the European Laryngological Society (ELS)

The term phonosurgery (PS) refers to any operation designed primarily for the improvement or restoration of voice. It is defined by the intended operative goal, which pertains to quality of life rather than its preservation, and informed consent needs to account for this emphasis. Since the aim is improvement or maintenance of vocal function, it is essential to document voice accurately pre-operatively. As important as the surgery itself is a team approach to perioperative care and rehabilitation. Although not a new concept, the PS portfolio of operations continues to grow rapidly, making this one of the most dynamic field in Laryngology. However, this has also led to confusion regarding terminology and classification, with the result that it is presently difficult to compare results between institutions. The aim of this paper is to establish a practical classification system for PS and to thereby establish a common language for reporting results. We propose four groups of operation: vocal fold surgery (VFS), laryngeal framework surgery (LFS), neuromuscular surgery (NHS) and reconstructive surgery (RCS) (for either partial or total laryngeal replacement).

The Efficacy of Mitomycin-C in the Treatment of Laryngotracheal Stenosis

OBJECTIVE

The purpose of this study is to evaluate whether the addition of topical mitomycin-C (MMC) application to the wound site after endoscopic treatment of laryngotracheal stenosis (LTS) resulted in measurable improvement in clinical outcomes.

STUDY DESIGN AND SETTING

A retrospective chart review of patients with LTS treated by the senior author over a 6-year period was performed. The treatment groups were stratified into two main categories: 1) endoscopic treatment alone and 2) endoscopic treatment + topical MMC. The "symptom-free" interval was determined (in months) for each subject using a two-tailed t test for statistical analysis of the control/study groups.

RESULTS

Sixty-seven procedures were performed in 36 patients with LTS with a mean of 1.86 surgical treatments per patient. The mean duration of the symptom-free interval after endoscopic treatment for LTS was 4.9 months in the endoscopic-only treatment group and 23.2 months in the endoscopic group receiving topical MMC. The symptom-free interval observed in the MMC group was significantly longer than the control subjects (P = 1 x 10).

CONCLUSIONS

The results of this study suggest that MMC is an effective adjuvant in the treatment of LTS. The results of this study provide strong supporting evidence that topical MMC is an effective adjuvant in the treatment of LTS.

Halofuginone prevents subglottic stenosis in a canine model

OBJECTIVES

Halofuginone is a low-molecular weight quinazolinone alkaloid coccidiostat that inhibits collagen type I synthesis, extracellular matrix deposition, and angiogenesis. This study was conducted to assess its potential in preventing subglottic stenosis (SGS).

METHODS

We induced SGS in 10 dogs randomly divided into 2 groups. Each group received treatment between 3 days before and 21 days after the induction of SGS. One group received oral halofuginone 40 microg/kg, and the other was given placebo. The area of the subglottic lumen was measured at baseline and 3 months later. In addition, human tracheal fibroblasts were cultured. The inhibitory effect of halofuginone was compared to the effect of mitomycin.

RESULTS

All dogs survived throughout the study with no side effects. Three months after the operation, no halofuginone-treated dog had SGS, in contrast to a 66% to 80% stenosis rate (mean, 72%) in controls (p < .008). Thick fibrotic tissue was found in the placebo-treated larynges, whereas an almost normal architecture was observed in halofuginone-treated larynges. Halofuginone inhibited the growth of human tracheal fibroblasts by 75%, in comparison with 60% inhibition by mitomycin (no statistically significant difference).

CONCLUSIONS

This preliminary study shows that halofuginone is effective in preventing SGS caused by an acute injury. Halofuginone has a potential therapeutic role in preventing SGS in humans.

Can Mitomycin C Really Prevent Airway Stenosis?

BACKGROUND/OBJECTIVES

Mitomycin C (MMC) is used in the prevention of upper airway stenosis. However, the efficacy of MMC is still debatable, and the potential complications of MMC use have been scarcely reported. We evaluated the efficacy and early complications of MMC in a wound model of the subglottis.

STUDY DESIGN

A randomized animal study.

METHODS

Sixty rabbits underwent a full-thickness injury to the posterior subglottis by diode laser. The animals were randomly assigned to three groups according to the different topical treatments of MMC 0.4 or 10 mg/mL or saline alone for 5 minutes. Animals were killed at 4 weeks, and gross and histologic findings were compared among different groups and 10 age-matched, non-wound, normal controls.

RESULTS

Thirty-two of the 60 (53%) animals died mainly of acute airway obstruction by necrotic debris, sloughs on, or cartilage collapse of the unhealed posterior subglottis during early weeks after wounding, higher in the MMC-treated animals (67%) than in the wound controls (25%) (P = .007). This resulted from the significant delay of wound healing in the MMC-treated groups compared with the wound controls (P = .012). The degree of subglottic stenosis was comparable among different groups (P > .8), although collagen deposition was significantly lower in the MMC-treated groups compared with the untreated controls (P = .036).

CONCLUSIONS

There was a significant risk of acute airway obstruction from delayed wound healing in rabbits that received subglottic laser wounding and MMC treatment. This risk should be considered in the use of MMC in clinical practice.

Airway complications from topical mitomycin C

OBJECTIVE

Topical application of mitomycin C appears to be a useful adjunct in reducing cicatricial scarring of the airways. Human and animal studies have demonstrated the efficacy and safety of mitomycin C topically in the treatment of airway stenosis at concentrations ranging from 0.4 mg/mL to 10 mg/mL. Although no reports of mitomycin C toxicity have been reported in the otolaryngology literature, the ophthalmologic literature has documented serious, vision-threatening complications resulting from the use of topical mitomycin C. The purpose of this study is to report complications related to mitomycin C use in the treatment of glottic and subglottic stenosis. Risk factors associated with these complications are identified.

STUDY DESIGN AND SETTING

A retrospective chart review of all patients treated by the senior author for laryngotracheal stenosis with endoscopic CO(2) laser incisions/dilation and adjuvant topical mitomycin C was performed to determine the incidence of complications. Variables studied included patient age and gender, location and severity of stenosis, medical comorbidities, length of procedure, postoperative instrumentation of the airway, and mitomycin C concentration.

RESULTS

Eighty-five cases of adjuvant topical mitomycin C use after CO(2) laser endoscopic treatment and dilation for upper airway stenosis were identified in a total of 44 patients. Complications that were believed to be caused by the local toxicity of mitomycin C occurred in 4 cases out of 85 (or 4.7%), manifested by accumulation of fibrinous debris at the operative site, resulting in partial airway obstruction and the need for emergent airway intervention.

CONCLUSIONS

Caution should be exercised when topical mitomycin C is used in the treatment of airway stenosis.

Successful treatment of laryngeal stenosis in laryngo-onycho-cutaneous syndrome with topical mitomycin C

Laryngo-onycho-cutaneous syndrome is a very rare entity found in Punjabi families. It affects the skin, nails, and larynx. Laryngeal involvement may cause lethal airway obstruction, and has in the past proved very difficult to treat. Mitomycin C is an antibiotic that acts as an alkylating agent, inhibiting DNA synthesis. It reduces fibroblast proliferation, and has previously been used to treat choanal atresia and laryngeal stenosis. We report an 18-year-old man with complete transglottic laryngeal stenosis secondary to laryngo-onycho-cutaneous syndrome. An airway was established by dissection with a bougie and sickle knife, and was initially maintained by the upper limb of a Montgomery T-tube. Laryngeal granulation tissue present on removal of the T-tube was treated with topical mitomycin C (2 mg/mL) applied for 4 minutes on two occasions with an interval of 1 month. A year later, the airway remained patent, with no granulation tissue.

Use of mitomycin C for treatment of keloid: a preliminary report

OBJECTIVES

Mitomycin C (MC) is an anti-neoplastic agent with an anti-proliferative effect on fibroblasts. We set out to evaluate the effect of MC application following keloid excision.

STUDY DESIGN AND SETTING

Patients with keloid in a tertiary referral center were enrolled in a prospective study. The scar was excised and prior to skin closure, a pledget with 1 cc of MC 0.4 mg/mL was applied for 5 minutes. Patient satisfaction and keloid thickness were assessed.

RESULTS

All patients were satisfied with the results, although complete disappearance of the keloid was evident only in two. Keloid thickness was measured and ranged from 5 to 26 mm. Following surgery and treatment at 2 months thickness ranged from 0 to 8 mm.

CONCLUSIONS

MC application following scar resection appears to be effective in treatment of keloid.

SIGNIFICANCE

As no specific effective treatment for keloid is currently available, utilization of this readily available therapeutic agent may improve treatment outcome.

Feasibility and safety of airway bypass stent placement and influence of topical mitomycin C on stent patency

OBJECTIVE

Airway bypass via transbronchial fenestration has been shown to improve forced expiratory volume and flow in explanted human emphysematous lungs. The aim of this study was to evaluate the feasibility and safety of in vivo airway bypass stent placement by using a canine model and to assess the influence of topical mitomycin C on the prolongation of stent patency.

METHODS

With dogs under general anesthesia, suitable segmental and subsegmental bronchial wall sites were selected by direct visualization with a flexible bronchoscope. Peribronchial blood vessel injury was avoided by using a Doppler probe. Transbronchial fenestration was formed with a 22-gauge transbronchial needle, and the passage was then dilated with a 2.5-mm angioplasty balloon. A balloon expandable stainless-steel stent (3 mm long x 3 mm wide) with a sleeve of silicone rubber covering was placed within the fenestration. Animals were bronchoscoped weekly to assess stent patency. Seventy stents were placed in 12 dogs. Thirty-five served as controls, and the other 35 received transbronchoscopic topical application of mitomycin C once weekly to evaluate the effect on the maintenance of stent patency. Mitomycin C stents were divided into 4 groups according to the number of treatments: group A, 1 treatment only; group B, 4 weeks; group C, 7 weeks; and group D, 9 weeks. Each once-weekly mitomycin C application consisted of 0.2 mL at a concentration of 1 mg/mL, delivered through a small polyethylene catheter.

RESULTS

Four instances of minor and brief bleeding occurred during stent placement and resolved without incident. One pneumothorax occurred and was treated by chest tube placement, without any adverse sequelae. There was no mortality associated with stent placement. No delayed hemorrhage or pneumothorax occurred. All control stents were occluded at the 1-week follow-up. The median durations of stent patency for group A (n = 8), group B (n = 9), group C (n = 10), and group D (n = 8) were 3, 8, 13, and greater than 20 weeks, respectively.

CONCLUSIONS

Airway bypass stent placement can be performed safely. In an animal model, most stents became occluded within 1 week, but topical mitomycin application resulted in significant prolongation of patency.

Topical application of mitomycin C prevents epineural scar formation in rats

The role of topically applied mitomycin C in preventing postoperative perineural fibrosis was examined by gross anatomical dissection and histological analysis in rats. The sciatic nerve was exposed bilaterally in 24 Wistar adult male rats, and an abrasion injury was produced on the exposed surface of the biceps femoris muscle in all animals. In the experimental group, cotton pads soaked with mitomycin C (0.5 mg/ml) were placed around the nerves for 5 min, whereas cotton pads soaked with saline were applied to the control group. Four weeks after surgery, the neurolysis sites were evaluated by blinded surgical dissection. Perineural adhesions were graded using a numerical grading scheme. The scar tissue formation index was also calculated, and a grading was made according to the number of fibroblasts/fibrocytes counted around the epineurium in histological evaluation. Mitomycin C-treated nerves showed significantly less perineural adhesions than controls. Quantification of the dense connective tissue surrounding the nerves revealed a statistically significant reduction around nerves treated with mitomycin C, and the number of fibroblast/fibrocytes was also significantly reduced. Application of topical mitomycin C might be effective in preventing epineural scar formation after neurolysis of peripheral nerves.

Mitomycine C : prévention et traitement des synéchies glottiques antérieures

OBJECTIVES

Topical applications of mitomycin C to the anterior glottis may prevent anterior glottic synechia (prevention group) or restenosis (treatment group).

METHODS

In the prevention group, six patients with glottic carcinoma involving the anterior commissure were treated by transoral laser surgery. Repeated procedures were performed in one patient. For the six patients in the treatment group, the anterior glottic synechia was secondary to frontolateral laryngectomy (three patients), transoral laser therapy for laryngeal papillomatosis (two patients) or bilateral glottic carcinoma (one patient). Mitomycin C (0.4 mg/ml) was used as a topical application on the anterior commissure for a duration of 4 minutes. Outcome was assessed clinically at three months using a visual scale: no synechia (success), micro-synechia (partial failure), and synechia (failure).

RESULTS

In the prevention group, there were six successes and one partial failure. In the treatment group, there were two successes, three partial failures, and one failure. No side effects were noted.

CONCLUSION

Topical application of mitomycin C was effective to prevent anterior glottic synechia after transoral laser surgery for glottic carcinoma involving the anterior commissure. It is an alternative to endolaryngeal keel in patients with sequellar synechia. These preliminary results should be further evaluated in a larger series.

Mitomycin Does Not Prevent Laryngotracheal Repeat Stenosis After Endoscopic Dilation Surgery: An Animal Study

OBJECTIVES/HYPOTHESIS

Conflicting data exist in the literature regarding the role of mitomycin in the prevention and treatment of laryngotracheal stenosis. The purpose of the study was to assess the value of mitomycin in preventing repeat stenosis after endoscopic dilation surgery of well-established stenoses.

STUDY DESIGN

Prospective controlled animal study.

METHODS

Laryngotracheal stenosis was induced in 16 dogs. After a period of 3 months the dogs underwent endoscopic dilation and were randomly divided into two groups. The control group received immediate topical application of normal saline. Dogs in the mitomycin group received immediate topical application of 0.5 mg mitomycin. The animals were then observed for 3 more months before euthanasia. The laryngeal lumens were measured endoscopically at baseline, before dilation, and before euthanasia. A comparison was made between the two study groups by means of the Wilcoxon rank-sum test for change in the percentage of stenosis attained by the endoscopic dilation.

RESULTS

Nine dogs were included in the control group, and seven in the mitomycin group. Group comparison for initial occlusion before endoscopic dilation using Wilcoxon rank-sum test showed no difference between the two groups (z = 0.16 [P =.87]). Three months after endoscopic dilation, no difference was observed between the two groups regarding the change in the percentage of occlusion (z = -0.21 [P =.83]).

CONCLUSION

Mitomycin exerts a benefit equal to that of normal saline when applied to a well-established laryngotracheal stenosis in dogs and does not prevent repeat stenosis after endoscopic dilation surgery.

The combined endoscopic CO2 laser posterior cordectomy and total arytenoidectomy for treatment of bilateral vocal cord paralysis

Upper airway obstruction, because of bilateral vocal cord paralysis, presents a serious challenge to the Otolaryngologist. Various surgical techniques have been advocated for the management of patients with vocal cord paralysis. Among these techniques, the individual use of laser CO(2) arytenoidectomy and posterior cordotomy has gained wide acceptance. In this report, we describe our experience in the management of bilateral vocal cord paralysis by combining posterior partial cordotomy as described by Dennis and Kashima, with total arytenoidectomy as described by Ossoff et al. We report the long-term results in the management of 18 patients treated in our department during the last 8 years.

Clinical and Histological Healing of Surgical Wounds Treated With Mitomycin C

OBJECTIVES/HYPOTHESIS

The proven ability of mitomycin C to inhibit fibroblasts in vitro has stimulated its use in research animals and in humans to control healing. The objective of the study was to follow the healing process of surgical wounds in the dorsum of rats treated topically with mitomycin C.

STUDY DESIGN

Prospective experimental study.

METHODS

Two distinct surgical wounds were made to the dorsum of 10 adult rats. One of the wounds received topical mitomycin C diluted at 0.5 mg/mL during a 5-minute period, and the other wound was used as a control. The healing process was followed clinically and histologically after the rats were killed at different post-treatment periods. The degree of fibrosis was evaluated histologically by two different pathologists.

RESULTS

Surgical wounds treated with mitomycin C presented delayed healing when compared with the untreated wounds, with remission of scabs 7 days after the control wounds. Histological analysis at 1 month after treatment revealed a significant reduction in fibrosis of the wounds treated with mitomycin C when compared with the untreated wounds. After the third month the degree of fibrosis was comparable in both wounds.

CONCLUSION

Topical mitomycin C delays the healing of surgical wounds in rats up to the fourth week following treatment, but the degree of fibrosis is comparable in both treated and untreated wounds after 12 weeks. In otolaryngology this characteristic of the drug may be useful in the treatment of external ear canal stenosis, choanal atresias, nasal cicatricial stenosis, laryngeal stenosis, and keloids.

Tratamento cirúrgico da otite média com efusão: tubo de ventilação versus aplicação tópica de mitomicina C

O uso do tubo de ventilação (TV) da orelha média, tratamento cirúrgico eleito da otite média com efusão (OME), não é isento de complicações, promovendo ainda limitação social pela necessidade de abandono dos banhos de imersão. A mitomicina C (MMC) é um antineoblástico, cuja aplicação tópica retarda a fibrose e previne a estenose cicatricial. Em cobaias, retardou o fechamento de timpanotomias, permitindo maior tempo de aeração da orelha média, à semelhança dos tubos de ventilação. FORMA DE ESTUDO: Clínico prospectivo. OBJETIVO: Comparar a eficácia entre timpanotomia, aspirado da efusão e inserção de tubo de ventilação (grupo TV) versus timpanotomia, aspirado da efusão e aplicação tópica de mitomicina C (grupo MMC). Comparar o tempo de manutenção da timpanotomia e a incidência de complicações nos dois grupos. RESULTADOS: O grupo MMC apresentou eficácia significativamente menor (52% versus 80%) que o grupo TV (p= 0,34). A presença de timpanometria tipo "B" e a ausência de comprometimento do óstio faríngeo tubário pelo tecido adenóide no pré-operatório representaram fatores de mau prognóstico. A aplicação tópica de MMC nas bordas da timpanotomia proporcionou um tempo de abertura da membrana timpânica por duas a três semanas. No grupo TV, a otorréia foi observada em 13,3% dos pacientes. No grupo MMC, apesar da menor eficácia, nenhum paciente apresentou complicações nem sofreu prolongada proibição dos banhos de imersão. CONCLUSÃO: Apesar de concluirmos que o TV apresenta maior eficácia, novos estudos utilizando maior concentração, maior tempo de aplicação ou o uso seriado de MMC no tratamento da otite média com efusão devem ser realizados.

O comportamento clínico e histológico da pele do rato submetida ao uso tópico e injetável de Mitomicina C

OBJETIVO: A Mitomicina C é um quimioterápico que apresenta a capacidade de inibir fibroblastos in vitro. Esta característica a levou a ser usada experimentalmente em animais de laboratório e no ser humano, principalmente em oftalmologia, para inibir o processo cicatricial. Este trabalho visa acompanhar o processo de cicatrização de feridas cirúrgicas feitas em dorsos de ratos e tratadas topicamente com Mitomicina C, comparando-as com feridas no mesmo local, não tratadas. Propõe-se também a avaliar a resposta da pele quando injetada com concentrações diferentes do medicamento. FORMA DE ESTUDO: Experimental. MATERIAL E MÉTODO: Foram feitas, em 10 ratos, duas feridas cirúrgicas em seus dorsos. Uma delas foi tratada topicamente com Mitomicina C na diluição de 0,5 mg/ml por 5 minutos e outra não. O processo de cicatrização destas feridas foi acompanhado clinicamente. Posteriormente, os ratos foram sacrificados em períodos diferentes, e suas feridas estudadas histologicamente quanto ao grau de fibrose por dois anatomopatologistas. Posteriormente, três ratos foram submetidos a injeções intradérmicas com concentrações diferentes de Mitomicina C, e o comprometimento local foi avaliado clínica e histologicamente, sendo que apenas na concentração de 0,01mg/ml não se observou necrose tecidual. RESULTADOS: As feridas tratadas com Mitomicina C tiveram seu processo cicatricial retardado, com o desaparecimento das crostas locais 7 dias após o das feridas não tratadas. Ao exame histológico, observado separadamente por dois anatomopatologistas, observou-se no primeiro mês uma nítida diminuição do grau de fibrose nas feridas tratadas com Mitomicina C em relação às não tratadas. Este grau de fibrose se iguala, nas duas feridas, no terceiro mês. Quanto às diluições injetadas, notou-se clínica e histologicamente uma necrose tecidual proporcional ao grau de concentração (0,5; 0,1; e 0,05 mg/ml), que não foi observada na concentração de 0,01mg/ml. CONCLUSÃO: A Mitomicina C usada topicamente em feridas cirúrgicas em ratos retarda seu processo de cicatrização até a 4ª semana. Na 12ª semana este processo se equaliza. Quando usada intradermicamente, causa necrose tecidual apenas em concentrações elevadas. Estas características da Mitomicina C podem ser usadas, em otorrinolaringologia, como coadjuvante no tratamento de estenoses do meato acústico externo, imperfurações coanais, sinéquias nasais, estenoses laríngeas e quelóides.

The effect of mitomycin on extracellular matrix proteins in a rat wound model

OBJECTIVE

To evaluate the effect of topical and injected mitomycin on the expression of extracellular matrix proteins by fibroblasts in an early surgical wound model.

STUDY DESIGN

A prospective, controlled study in a rat wound model.

METHODS

Six linear incisions were placed on the backs of each of three Sprague-Dawley rats, and polyvinyl alcohol sponges were implanted. Two control wounds were implanted with saline-soaked sponges. The two topical test group wounds were treated with 0.5 mg/mL topical mitomycin for 2 minutes, followed by sponge implantation. The two injection test group wounds were injected with 0.3 mL mitomycin (0.5 mg/mL) before incision and sponge implantation. Each incision was closed uniformly with 3-0 nylon suture. The sponges were harvested on the tenth postoperative day. Fibroblasts that had grown into the sponges were separated, and polymerase chain reaction analysis was used to quantify the expression of messenger RNA for several extracellular matrix proteins.

RESULTS

The expression of mRNA for some extracellular matrix proteins (elastase, hyaluronidase, and procollagen) was downregulated in the mitomycin test groups. The effect was more pronounced in the topical mitomycin test group compared with the injection test group. The wounds in the topical group were prone to dehiscence, and the wounds in the injection group demonstrated poor healing when compared with controls.

CONCLUSIONS

Mitomycin may inhibit wound healing by downregulating the gene expression for extracellular matrix proteins. This effect may be selective and may be more pronounced on inducible genes. Such findings prompt further studies regarding possible "best time" windows and selective gene suppression. The use of mitomycin may be limited in situations where wound integrity is necessary.

Mitomycin C for the prevention of adhesion formation after endoscopic sinus surgery: a randomized, controlled study

OBJECTIVE

Mitomycin C (MMC) is an antineoplastic agent that has been shown to decrease scar tissue after ophthalmologic surgery. Our goal was to determine whether the application of MMC at the conclusion of sinus surgery decreases the incidence of postoperative adhesion formation.

METHODS

At the completion of endoscopic sinus surgery in 55 patients, a cotton pledget saturated with 1 mL of 0.4 mg/mL MMC was placed for 4 minutes in the right or left middle meatus and a similar saline-soaked pledget was placed on the opposite side. Patients were examined postoperatively by a masked observer for the presence of synechiae and mucosal changes.

RESULTS

Postoperative adhesions were observed in 16 patients (29%) with a mean follow-up of 4.1 months. These adhesions were bilateral in 6 patients (10.9%) and unilateral in 10 patients (18%). Unilateral adhesions were observed on only 2 sides (3.6%) treated with MMC and 8 controls (14.5%) (P = 0.058). No adverse effects were observed.

CONCLUSIONS

MMC was found to be safe to use during sinus surgery, and it may reduce the incidence of postoperative adhesions at the dosage used in this study.

SIGNIFICANCE

Because of the observed trend toward decreased synechiae formation with MMC application, further trials using higher concentrations and application times are warranted.