Prevention of Posterior Glottic Stenosis by Mitomycin C

"Quality, Readability, and Understandability of Online Posterior Glottic Stenosis Information"

OBJECTIVES

To assess the quality, readability, and understandability of posterior glottic stenosis (PGS) information available to patients online.

METHODS

The top 50 Google search results for "posterior glottic stenosis" were categorized based on website affiliation and target audience (patient or provider). Readability was assessed using the Flesch-Kincaid Grade Level (FKGL) and the Flesch Reading Ease (FRE) scores. The DISCERN tool was used to assess quality and the Patient Education Assessment Tool for Printed Materials (PEMAT-P) was used to assess understandability and actionability. Simple descriptive statistics were used to analyze the data.

RESULTS

36 of the top 50 results were eligible for scoring. 17% (6 of 36) were classified as patient-focused while 83% (30 of 36) were provider-focused. Patient-focused materials had a higher mean FRE score (36.9) than provider-focused materials (15.5) (P < 0.001). Patient-focused materials had an average reading level of 12.5 compared to 15.8 for provider-focused materials (P < 0.001). There was a significant correlation between overall PEMAT-P and DISCERN (r = 0.63, P < 0.001), PEMAT-P understandability and DISCERN (r = 0.63, P < 0.001) and FRES and FKGL (r = -0.67, P < 0.001). From this, we can infer that higher quality sites are easier to understand but not necessarily tailored to a certain reading level.

CONCLUSIONS

Shared decision making in PGS management is crucial as patients must be aware of how treatment modalities affect airway, voice, and swallowing. However, this study shows that patient targeted PGS information is limited, and the readability, quality, and understandability is generally low. We suggest the development of web pages with PGS information tailored for patient education and search optimization to make this information appear earlier in Google search results. Furthermore, future studies should seek to characterize the link between online health information and socioeconomic-based health disparities.

Type I Posterior Glottic Stenosis: Natural History and In-Office Management

Objectives:

To review the natural history of type I posterior glottic stenosis (PGS-I) and its treatment outcomes through a case presentation and demonstrate the feasibility of in-office management of PGS-I.

Methods:

The case of a middle-aged woman who developed PGS-I after prolonged intubation is presented. A review of the literature on management and treatment outcomes of PGS-I is also performed.

Results:

Initially presenting with a large granuloma that failed conservative management, the patient deferred surgical intervention and developed unilateral vocal fold hypomobility with posterior glottic synechia. The adhesion was successfully ablated in the office with potassium-titanyl-phosphate (KTP) laser; however, vocal fold hypomobility persisted after treatment.

Conclusions:

This case illustrates the natural history of the development of PGS-I, demonstrates the feasibility of office-based management of this condition, and provides further evidence that lysis of PGS-I synechia does not uniformly lead to restoration of normal laryngeal function and mobility.

Role of Topical Medication in Prevention of Post-extubation Subglottic Stenosis

Iatrogenic laryngotracheal injury is the most serious complication of endotracheal intubation since this method of establishing airway was first described by Eugene Bouchut in 1858. Even today, subglottic stenosis is the most dreaded complication of intubation. This animal study is focused on the host tissue response to intubation induced injury resulting in subglottic stenosis and methods to prevent this complication. To assess the role of topically applied Mitomycin-C and Triamcinolone Acetonide in wound healing process following post-extubation subglottic injury. Prospective Randomized block, single-blinded, experimental study. Forty New-Zealand white rabbits where block randomized and allocated into 4 groups based on the type of topical medication that was applied post-extubation. Further these groups where subdivided into 3 subgroups based on the time of sacrifice (4, 6 and 12 weeks) to study the histopathological changes that occurred in a temporal sequence at the subglottis. It was observed that the rabbits in the control group and those that received Mitomycin-C only had more respiratory distress compared to those treated with Triamcinolone Acetonide. Statistically significant histopathological changes were observed in all the 4 groups. Mitomycin-C applied topically did not alter the wound healing process following post-extubation injury in the subglottis. Triamcinolone Acetonide significantly altered wound healing in the subglottis and prevented occurrence of respiratory distress.

Minimally invasive endoscopic treatment for pediatric combined high grade stenosis as a laryngeal manifestation of epidermolysis bullosa

Epidermolysis bullosa refers to a clinically and genetically heterogeneous group of inherited mucocutaneous diseases. Laryngotracheal lesions are momentous regarding the risk of sudden airway obstruction. The traditional treatment is tracheostomy. This case report highlights the advantages of minimally invasive interventions. A successful combined endoscopic management of a life-threatening respiratory crisis is presented in a 4-year-old child. Combined commissure stenosis with supraglottic spread was treated by CO₂ laser dissection and bilateral endoscopic arytenoid abduction lateropexy, supplemented with mitomycin C application. Due to expectable less scarring, the combination of these modern methods may be an efficient solution in these vulnerable respiratory tracts.

Predictors of Posterior Glottic Stenosis: A Multi-Institutional Case-Control Study

OBJECTIVE

To assess intrinsic and extrinsic risk factors in the development of posterior glottic stenosis (PGS) in intubated patients.

METHODS

Patients diagnosed with PGS between September 2012 and May 2014 at 3 tertiary care university hospitals were included. Patient demographics, comorbidities, duration of intubation, endotracheal tube (ETT) size, and indication for intubation were recorded. Patients with PGS were compared to control patients represented by patients intubated in intensive care units (ICU).

RESULTS

Thirty-six PGS patients were identified. After exclusion, 28 PGS patients (14 male, 14 female) and 112 (65 male, 47 female) controls were studied. Multivariate analysis demonstrated ischemia (P < .05), diabetes (P < .01), and length of intubation (P < .01) were significant risk factors for the development of PGS. Fourteen of 14 (100%) males were intubated with a size 8 or larger ETT compared to 47 of 65 (72.3%) male controls (P < .05). Posterior glottic stenosis (P < .01), length of intubation (P < .001), and obstructive sleep apnea (P < .05) were significant risk factors for tracheostomy.

CONCLUSION

Duration of intubation, ischemia, diabetes mellitus, and large ETT size (8 or greater) in males were significant risk factors for the development of PGS. Reducing the use of size 8 ETTs and earlier planned tracheostomy in high-risk patients may reduce the incidence of PGS and improve ICU safety.

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.

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.

The combined endoscopic management of congenital laryngeal web

Laryngeal web in the anterior commissure is a rare congenital anomaly often leading to severe dyspnea. Endoscopic procedures based on a simple transsection in these cases may worsen the condition because vocal folds have a tendency for fibrosis and granulation tissue formation after surgical interventions. Thus the traditional treatment of choice is the demanding, externally performed laryngotracheal reconstruction generally with a rib cartilage graft and longer period of stenting. This report presents the successful endoscopic management of a congenital laryngeal web in a 2-year-old boy, who previously underwent an uneffective scar laser transsection that led to excessive glotto-subglottic refibrosis. After the CO(2)-laser transsection the authors applied Mitomycin-C and inserted a combined silicon stent by extra-endolaryngeal technique. After the removal of the stent the patient could be decannulated and his voice improved. The application of these minimally invasive endoscopic techniques was successful, hence it may be an effective alternative treatment option for laryngeal webs.

[Adjuvants in operative laryngology: corticosteroids, fibrin adhesives, Mitomycin C]

Medicinal adjuvants are often used in operative laryngology but their value is judged very differently. The scientific evidence is unsatisfactory for most of these substances. For corticosteroids it is proven that in pediatric intensive care they reduce stridor following extubation. Routine prophylactic use for intubation does not seem to be justified and methylprednisolone and dexamethasone are the preferred preparations. Fibrin adhesives are well tolerated and low in side-effects. The indications for their use should be primarily limited due to the cost factor. Their use in laryngology remains a decision on an individual case-to-case basis. Mitomycin C is used because of its antiproliferative effect on fibroblasts in order to reduce scar tissue formation. Many positive effects have been attributed to the topical application but there are large differences in dosage and exposure time.

The preventive effect of halofuginone on posterior glottic stenosis in a rabbit model

Objective

The aim of this study was to investigate the preventive effect of halofuginone on posterior glottic stenosis (PGS) in an animal model.

Study Design

A randomized, controlled animal study.

Subjects and Methods

Sixteen male New Zealand White rabbits were used for this study. After the mucosa of posterior glottis was removed for producing PGS, the study group (eight rabbits) was given intraperitoneal halofuginone at 0.1 mg/kg/day for 4 weeks and saline was injected into peritoneum in the control group. At 4 weeks after injury, postsurgical changes of posterior glottis were evaluated by gross and histologic examination.

Results

PGS was induced by the mucosal stripping of the posterior glottis. The halofuginone-treated group showed less scarring and granulation tissue formation. Also, the degree of synechia was significantly less than that of control group. Histologic analysis showed the decreased fibrosis in the halofuginone-treated group.

Conclusion

This study suggests that halofuginone can be helpful in preventing PGS after laryngeal injury.

Application of topical mitomycin C to the base of shave-removed keloid scars to prevent their recurrence

BACKGROUND

Keloid scars are formed by over-activity of fibroblasts producing collagen and they cause significant morbidity both from their appearance and from their symptoms. Existing treatments are often unsatisfactory. Topical mitomycin C is known to inhibit fibroblast proliferation.

OBJECTIVES

To determine whether application of mitomycin C to the base of shave-removed keloids would prevent their recurrence.

METHODS

Ten patients had all or part of their keloid shave-removed. After haemostasis topical mitomycin C 1 mg mL(-1) was applied for 3 min. This application was repeated after 3 weeks. The keloids were photographed before treatment and the patients were reviewed every 2 months for a total of 6 months when a final photograph of the keloid site was taken. The patients and the Clinical Trials Unit staff scored the outcome on a linear analogue scale of 0-10, where 0 = disappointed and 10 = delighted. The pretreatment and 6-month post-treatment photographs were also assessed by two dermatologists who were not involved in the clinical trial.

RESULTS

Four of the 10 patients were delighted with the outcome of treatment and only one was disappointed. On average there was an 80% satisfied outcome.

CONCLUSIONS

This new treatment of keloids has been shown to be effective in the majority of patients but further studies are required to confirm this benefit.

Application of mitomycin C after endoscopic lysis of congenital laryngeal web combined with epiglottic hypoplasia in a middle-aged man

Laryngeal webs and epiglottic hypoplasias are uncommon congenital anomalies. Anterior glottic web combined with epiglottic hypoplasia was found in a middle-aged man presenting with hoarseness and dyspnea on exertion. This can be considered as a unique isolated defect of the larynx during early fetal development. The laryngeal web can be successfully treated in a single stage with endoscopic lysis and topical application of mitomycin C for prevention of anterior glottic restenosis. This case and prior reports suggest that the novel approach may be effective in the treatment of laryngeal webs.

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.