The Effect of Radiofrequency and Mitomycin C on the Closure Rate of Human Tympanostomy

Chronic tympanic membrane perforation: Histopathological evidence of the experimental model

OBJECTIVES

This study aims to compare the effectiveness of three different models of chronic tympanic membrane perforations.

MATERIALS

The experimental study included 18 male chinchillas, divided into 3 equal groups. Group 1 perforations were performed with infolding technique myringotomy. Laser myringotomy was performed for perforation creation in Group 2. Group 3 perforations were performed with infolding myringotomy combined with ventilation tube insertion. At the end of the follow-up period, which lasts 8 weeks, all tympanic membranes with patent perforations were examined histologically.

RESULTS

Although, the mean perforation patency in Group 2 was significantly higher than in Group 1 (5 vs. 2.4 weeks, p < 0.01), both of them failed in creation of chronic perforation according to time parameters. Group 3 demonstrated the longest mean perforation patency among investigated models (8 weeks). In Group 3, histological examination of perforations, which were considered to be chronic, revealed, that stratified squamous epithelium continued from the lateral surface around the perforation edge to join with the medial mucosal layer of TM.

CONCLUSION

Our findings demonstrated that the combination of infolding technique and ventilation tube insertion seems to be a potential candidate for an effective animal model of tympanic membrane perforation. Further large-scale studies are required to verify our promising results.

The History of Myringotomy and Grommets

The first recorded myringotomy was in 1649. Astley Cooper presented 2 papers to the Royal Society in 1801, based on his observations that myringotomy could improve hearing. Widespread inappropriate use of the procedure followed, with no benefit to patients; this led to it falling from favor for many decades. Hermann Schwartze reintroduced myringotomy later in the 19th century. It had been realized earlier that the tympanic membrane heals spontaneously, and much experimentation took place in attempting to keep the perforation open. The first described grommet was made of gold foil. Other materials were tried, including Politzer's attempts with rubber. Armstrong's vinyl tube effectively reintroduced grommets into current practice last century. There have been many eponymous variants, but the underlying principle of creating a perforation and maintaining it with a ventilation tube has remained unchanged. Recent studies have cast doubt over the long-term benefits of grommet insertion; is this the end of the third era?

Surgical treatments for otitis media with effusion: a systematic review

BACKGROUND AND OBJECTIVE

The near universality of otitis media with effusion (OME) in children makes a comparative review of treatment modalities important. This study's objective was to compare the effectiveness of surgical strategies currently used for managing OME.

METHODS

We identified 3 recent systematic reviews and searched 4 major electronic databases. Eligible studies included randomized controlled trials, nonrandomized trials, and cohort studies that compared myringotomy, adenoidectomy, tympanostomy tubes (tubes), and watchful waiting. Using established criteria, pairs of reviewers independently selected, extracted data, rated risk of bias, and graded strength of evidence of relevant studies. We incorporated meta-analyses from the earlier reviews and synthesized additional evidence qualitatively.

RESULTS

We identified 41 unique studies through the earlier reviews and our independent searches. In comparison with watchful waiting or myringotomy (or both), tubes decreased time with OME and improved hearing; no specific tube type was superior. Adenoidectomy alone, as an adjunct to myringotomy, or combined with tubes, reduced OME and improved hearing in comparison with either myringotomy or watchful waiting. Tubes and watchful waiting did not differ in language, cognitive, or academic outcomes. Otorrhea and tympanosclerosis were more common in ears with tubes. Adenoidectomy increased the risk of postsurgical hemorrhage.

CONCLUSIONS

Tubes and adenoidectomy reduce time with OME and improve hearing in the short-term. Both treatments have associated harms. Large, well-controlled studies could help resolve the risk-benefit ratio by measuring acute otitis media recurrence, functional outcomes, quality of life, and long-term outcomes. Research is needed to support treatment decisions in subpopulations, particularly in patients with comorbidities.

Effect of mitomycin on normal dermal fibroblast and HaCat cell: an in vitro study

OBJECTIVE

To evaluate the effects of mitomycin on the growth of human dermal fibroblast and immortalized human keratinocyte line (HaCat cell), particularly the effect of mitomycin on intracellular messenger RNA (mRNA) synthesis of collagen and growth factors of fibroblast.

METHODS

The normal dermal fibroblast and HaCat cell were cultured in vitro. Cell cultures were exposed to 0.4 and 0.04 mg/ml of mitomycin solution, and serum-free culture medium was used as control. The cellular morphology change, growth characteristics, cell proliferation, and apoptosis were observed at different intervals. For the fibroblasts, the mRNA expression changes of transforming growth factor (TGF)-β1, basic fibroblast growth factor (bFGF), procollagen I, and III were detected by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The cultured normal human skin fibroblast and HaCat cell grew exponentially. A 5-min exposure to mitomycin at either 0.4 or 0.04 mg/ml caused marked dose-dependent cell proliferation inhibition on both fibroblasts and HaCat cells. Cell morphology changed, cell density decreased, and the growth curves were without an exponential phase. The fibroblast proliferated on the 5th day after the 5-min exposure of mitomycin at 0.04 mg/ml. Meanwhile, 5-min application of mitomycin at either 0.04 or 0.4 mg/ml induced fibroblast apoptosis but not necrosis. The apoptosis rate of the fibroblast increased with a higher concentration of mytomycin (p<0.05). A 5-min exposure to mitomycin at 0.4 mg/ml resulted in a marked decrease in the mRNA production of TGF-β1, procollagen I and III, and a marked increase in the mRNA production of bFGF.

CONCLUSIONS

Mitomycin can inhibit fibroblast proliferation, induce fibroblast apoptosis, and regulate intracellular protein expression on mRNA levels. In addition, mitomycin can inhibit HaCat cell proliferation, so epithelial cell needs more protecting to avoid mitomycin's side effect when it is applied clinically.

Histopathological and ultrastructural effects of cutting radiofrequency energy on palatal soft tissues: a prospective study

Radiofrequency (RF) surgery has gained popularity as a safe and effective method for treating patients with snoring and mild obstructive sleep apnoea (OSA). Both interstitial and cutting radiofrequency energy may be used for multi-segmental management of the upper airway. Little is known about the effect of cutting radiofrequency energy on human soft palate. Excessive collateral injury may have an impact on tissue healing and functional outcomes. A histological analysis of specimens of human soft palate and uvula following resection with cutting RF energy was performed. In addition, ultrastructural analysis using scanning electron microscopy of excision margins was performed and compared with CO(2) LASER. Twelve patients were included. In ten patients, specimens of redundant uvula and faucial pillars were collected and underwent formal histological analysis. The maximum depth of tissue injury was 1 mm in two specimens and overall average depth of injury was 0.15 mm. Injury depth was independent of tissue subtype at the resection margin. Ultrastructural analysis demonstrated accurate incision when compared to CO(2) LASER. Cutting RF energy causes minimal collateral injury to the soft palate during resection for the treatment of snoring and mild OSA. A detailed knowledge of local effects on resection specimens allows accurate inference of in vivo tissue injury at the resection margin and may enable more precise prediction of healing patterns and repair.

Mitomycin C-associated radiofrequency microelectrocautery used in myringotomy in an animal model

This study aimed at describing an alternative surgical technique to the insertion of a ventilation tube in the tympanic membrane: myringotomy by radiofrequency alone and associated with mitomycin C.

AIM

to show a surgical approach that can be simple to execute, not subject to complications arising from the ventilation tube.

MATERIALS AND METHODS

we compared myringotomy by microknife and by radiofrequency microcautery (0.3 mm and 0.7 mm tips) alone and associated with mitomycin C, considering the time of tympanic closure in Wistar rats. Experimental study.

RESULTS

there was a statistically significant difference between radiofrequency myringotomy and knife myringotomy. As we analyze the radiofrequency approach with the 0.7 mm tip associated with mitomycin C (Wilcoxon test), the p value found was lower than 0.001, showing a statistical significance. The maximum tympanic membrane closure time was 44 days and the median found was 14 days.

CONCLUSION

the radiofrequency myringotomy (with the larger diameter tip) associated with mitomycin C enhances the tympanic membrane healing time.

Effect of topical use of mitomycin C and 5-fluorouracil on the closure time of myringotomies created by radiofrequency unit

CONCLUSION

Both mitomycin C (MC) and 5-fluorouracil (5-FU) had a significant effect in prolonging the patency rate of radiofrequency myringotomy.

OBJECTIVE

To compare the effect of topical use of MC and 5-FU on the closure time of myringotomies created by a radiofrequency unit.

MATERIALS AND METHODS

Myringotomies were performed using a radiofrequency unit on 80 tympanic membranes of 40 rats. Rats were divided into two study groups and one control group. MC (0.4 mg/ml) and 5-FU (50 mg/ml) pledgets were applied topically in the right ears (study groups, 20 ears each) for 10 min and saline pledgets in the left ears (control group, 40 ears). Animals were monitored using otomicroscopy weekly and patency rates were recorded until myringotomy closure.

RESULTS

The mean patency times were 4.85 weeks for the MC group and 3.90 weeks for the 5-FU group. The mean patency rate for the control side was 1.30 weeks. The log-rank test revealed both study groups to have a significantly longer patency time than the control group (p<0.0001). Although the patency rate was found to be higher in the MC-treated group than the 5-FU-treated group, this difference was not statistically significant (p>0.05).

Radiophonosurgery of vocal fold nodules

PURPOSE OF REVIEW

To describe the current support in the literature for radiophonosurgery in cases of vocal fold nodules.

RECENT FINDINGS

Radiophonosurgery is a recent innovation in the field of laryngeal surgery. It is emerging as a reliable and practical method for treating benign superficial vocal fold lesions that is increasingly becoming popular. It induces an excellent subjective and objective improvement in voice parameters. Histologically, it produces unremarkable lateral thermal damage and char penetration, which is quite crucial in a functional surgery such as in phonosurgery. Well designed probes are still lacking in the market.

SUMMARY

Radiophonosurgery provides a new approach for patients with vocal fold nodules. It combines the advantages of both cold knife and laser phonosurgery and is easy, well tolerated, precise and effective with excellent tactile and hemostatic properties.

Comparative study of laser versus radiofrequency myringotomy in rabbits: The effectiveness of mitomycin C application

OBJECTIVE

To compare laser-assisted tympanostomy (LAT) with radiofrequency myringotomy (RFM), as well as the effectiveness of mitomycin C (MC) on the above techniques, in rabbits.

STUDY DESIGN

Experimental animal research protocol.

SETTING

University of Crete, School of Medicine, Medical Experimental Education and Research Center.

METHODS

Bilateral myringotomies were performed under general anesthesia on 40 rabbits. LAT was performed on 20 animals (40 ears) and RFM on the remaining 20 animals (40 ears). MC (0.3 mg/mL) pledgets were applied to the right ears and saline pledgets to the left ears. Animals were monitored weekly using otomicroscopy until myringotomy closure. Kaplan-Meier survival techniques were used to compare myringotomy patency times.

INTERVENTIONS

Under general anesthesia, bilateral LAT was performed on 20 rabbits and bilateral RFM on 20 rabbits.

MAIN OUTCOME MEASURES

Myringotomy patency time.

RESULTS

The mean patency times of the saline-treated ears were: 1.85 weeks (95% confidence interval [CI], 1.556-2.144 wk) for the LAT group and 1.70 weeks (95% CI, 1.494-1.906 wk) for the RFM group. This difference was not significant (p > 0.5). MC application significantly prolonged mean patency time (p < 0.0001) in both LAT and RFM groups. The mean patency times in the MC-treated ears were 5.45 weeks (95% CI, 5.226-5.674 wk) for the LAT group and 5.55 weeks (95% CI, 5.285-5.815 wk) for the RFM group. This difference was not significant (p > 0.5).

CONCLUSION

There is no significant difference in myringotomy patency times between LAT and RFM techniques in rabbits, whereas MC significantly prolongs the patency rate of either technique.

Chronic tympanic membrane perforation: a better animal model is needed

Developments in the treatment of chronic tympanic membrane perforation have been hindered by the lack of an ideal animal model. It is not appropriate to test such treatments on acute perforations as the majority of these heal spontaneously. An ideal animal model would be one that most closely resembles the human clinical situation. It should be inexpensive, readily available, and easy to create. There have been a number of attempts to create a chronic tympanic membrane perforation model with limited success. All published attempts at chronic tympanic membrane perforations have been reviewed and the limitations of each model are discussed. A number of areas for research exist for further developing a chronic tympanic membrane perforation model. These areas include a perforation model in the presence of bacteria and eustachian tube dysfunction. Understanding the molecular and genetic mechanisms of chronic otitis media and potential treatments will also be useful.

Pilot comparison between potassium titanyl phosphate laser and bipolar radiofrequency in paediatric tonsillectomy

OBJECTIVES

To compare the advantages and disadvantages of potassium titanyl phosphate laser with those of bipolar radiofrequency techniques, in paediatric tonsillectomy.

STUDY DESIGN

Prospective, randomised, clinical study.

PATIENTS AND METHODS

From July 2004 to April 2006, 80 patients aged between 10 and 15 years, with tonsillectomy planned for chronic tonsillitis, were included in the study. Children were prospectively randomised into two equal groups: potassium titanyl phosphate laser tonsillectomy and bipolar radiofrequency tonsillectomy. Operative time and intra-operative blood loss were recorded. Patients were scheduled for follow up during the first, second and fourth post-operative weeks. They were asked to record their pain and discomfort on a standardised visual analogue scale, from zero (no pain) to 10 (severe pain). Post-operative complications were also recorded and managed.

RESULTS

The potassium titanyl phosphate laser group showed a slightly longer operative time (mean 12 minutes) than the bipolar radiofrequency group (mean 10 minutes). Intra-operative blood loss was significantly less in the potassium titanyl phosphate laser group (mean 21 cm3) than in the bipolar radiofrequency group (mean 30 cm3). In the first week, post-operative pain scores were less in the potassium titanyl phosphate laser group than in the bipolar radiofrequency group (means 7.5 and 8.5, respectively). However, in the second week pain scores increased more in the potassium titanyl phosphate laser group than in the bipolar radiofrequency group (means 8.5 and 6, respectively). In the fourth week, both groups showed equal and nearly normal pain scores. No case of reactionary post-tonsillectomy haemorrhage was recorded in either group. Only one case of secondary post-tonsillectomy haemorrhage was recorded, in the potassium titanyl phosphate laser group (2.5 per cent), managed conservatively.

CONCLUSION

Both the potassium titanyl phosphate and the bipolar radiofrequency techniques were safe and easy to use for tonsillectomy, with reduced operative time, blood loss and complication rates and better post-operative general patient condition. Potassium titanyl phosphate laser resulted in reduced operative bleeding and immediate post-operative pain, compared with the bipolar radiofrequency technique. However, potassium titanyl phosphate laser required slightly more operative time and caused more late post-operative pain than the bipolar radiofrequency technique. The low rate of recorded complications showed that both techniques cause little damage to the tonsillar bed during dissection, thus minimising complications.

5-Fluorouracil Ointment for the Treatment of Otitis Media With Effusion

OBJECTIVES/HYPOTHESIS

Our aim was to evaluate the combined effect of 5-fluorouracil (5-FU) and myringotomy for the treatment of otitis media with effusion (OME). OME is usually treated with medication, myringotomy, or insertion of a ventilation tube (VT). Except for VT insertion, however, treatment effects are short-lived. VT insertion has numerous sequelae: increased susceptibility to infection, large perforation of the tympanic membrane, cholesteatoma, and eventual hearing deterioration. We estimated the depressant action of 5-FU on normal cell proliferation in vitro. In addition, clinically, we assessed whether 5-FU has the potential to prolong the effect of myringotomy.

STUDY DESIGN

An in vitro study and a clinical study were conducted.

MATERIALS AND METHODS

In study I, fibroblasts harvested from the peritoneum of three green fluorescent protein transgenic mice were cultured with different doses of 5-FU. After 2 weeks, their proliferation rates were compared. In study II, patients (54 males, 47 females) were selected randomly from a group of patients with intractable OME. Myringotomy with or without a single dose of 5-FU ointment (approximately 0.10-0.30 mg) was performed in group I (n = 64) and group II (n = 37), respectively. The natural closure rates of the tympanic membrane were assessed in both groups.

RESULTS

In vitro, 5-FU inhibited the growth of fibroblasts in a dose-dependent manner. The average time to tympanic membrane closure was 20.5 days in group I and 8.1 days in group II. No adverse events were observed in either group.

CONCLUSIONS

Topical application of 5-FU ointment is useful in prolonging the effect of myringotomy. 5-FU ointment therapy is easy, safe, and cost-effective and may be of wide application.

Topical Application of Mitomycin C to the Middle Ear Is Ototoxic in the Gerbil

HYPOTHESIS

Mitomycin C is ototoxic when applied topically to the structures of the middle ear.

BACKGROUND

Mitomycin C is a topically applied medication widely used in a variety of surgical procedures to prevent excessive scar tissue formation. Its safety for use during otologic procedures has not been fully evaluated.

METHODS

A laboratory study was undertaken using the Mongolian gerbil as an animal model. Both acute and chronic effects on cochlear function of mitomycin C were assessed with measurements of compound action potential (CAP) thresholds of the auditory nerve, CAP input/output functions, distortion product otoacoustic emissions, and endocochlear potentials. Morphologic changes were assessed with light microscopy using hematoxylin-eosin staining as well as transmission electron microscopy.

RESULTS

Five-minute applications of mitomycin C (0.5 mg/ml) to the entire surface of the middle ear adversely affected CAP thresholds, input/output functions, distortion product otoacoustic emissions, and the endocochlear potential. Ninety-minute exposures of mitomycin C solely to the round window produced similar changes. Histologic evaluation of animals 1 week after treatment showed damage to cochlear hair cells, the stria vascularis, and spiral ganglion neurons when compared with controls.

CONCLUSION

Mitomycin C can produce substantial sensorineural hearing loss when applied topically to the gerbil middle ear for even brief periods. Consequently, its safety for topical use in the human middle ear is highly questionable.

Bipolar radiofrequency dissection tonsillectomy: a prospective randomized trial

OBJECTIVES

To conduct a prospective randomized controlled study presenting and comparing bipolar radiofrequency dissection tonsillectomy (BRDT) to cold dissection tonsillectomy (CDT) regarding intra-operative blood loss, operative time, postoperative pain, and postoperative complications including hemorrhage.

MATERIALS AND METHODS

From January 2004 to March 2005, 200 children planned to undergo tonsillectomy were included in this study. Children were prospectively randomized into two equal groups: bipolar radiofrequency dissection tonsillectomy and cold dissection tonsillectomy. The operative time and intra-operative blood loss were recorded. Children were asked to record their pain on a standardized visual analog scale on days 1, 4, 7, and 14. All children were reviewed on the 4th, 7th, and 14th day after surgery. Postoperative complications were recorded and dealt with.

RESULTS

There was a shorter operative time (mean 8.5 minutes, P < 0.001) in the radiofrequency group. BRDT showed a decrease of 7 minutes in the mean when compared to the CDT group. The amount of blood lost during BRDT was minimal (mean 13 cc), with a mean difference of 69 cc when compared to CDT (P < 0.001). There was no statistical significant difference in pain score between the two groups except in the first postoperative day where the BRDT demonstrated a statistically significant lower parameters (P < 0.05). No evidence for statistically significant difference between the two groups regarding postoperative complications.

CONCLUSION

BRDT is a new, easy, and safe technique that offers a complete eradication of the tonsillar disease, short operating time, minimal intra-operative blood loss, and a suitable cost with no additional increase in postoperative pain and hemorrhage when compared to the conventional CDT. Our experience promotes BRDT as the preferred method of tonsillectomy.