Supervisors info:
Νικολόπουλος Θωμάς, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Μαραγκουδάκης Παύλος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Δελίδης Αλέξανδρος, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Summary:
Introduction: Otosclerosis related procedures provide the surgical solution for the conductive hearing loss associated with the condition. A number of different techniques has been described in the literature. Our aim is to record and classify the described techniques. We will also attempt to compare the ones with available sufficient date for their effectiveness and safety profile.
Methodology: Literature research in the electronic databases PubΜed, Web of Science και Cochrane Library was conducted by using the terms “otosclerosis treatment” and
“otosclerosis management”. Exclusion criteria included non-surgical treatment, non-clear description of the surgical technique to allow classification of the treatment modality and non- measurable criterion of the postoperative hearing difference. Ideally description of complications should be mentioned in the publication. It was decided that slight modifications of the described technique would not result to sub classifications to as this would lead into numerous variations making results interpretation extremely difficult or impossible.
Results: The techniques of stapedotomy, stapedectomy, laser assisted otosclerosis treatment and endoscopic assisted otosclerosis treatment were the distinct ones for which enough data were available and could potentially lead to conclusions. 46 publications were included in the study and their results are presented in three different tables for reader’s convenience.
Discussion and Conclusions: Stapedectomy and stapedotomy are the surgical treatments of choice for the conductive hearing loss associated with the condition. They have demonstrated repeatedly excellent success rates with their results remaining stable postoperatively even after decades and significantly improving patients’ quality of life while maintaining an excellent safety profile.
The percentage of patients for which a mean postoperative air- bone gap (ABG) closure of less than 10 dΒ has been achieved, lies between 75% and 90% in almost all publications for both stapedotomy and stapedectomy. For frequencies up to 2 kHz, there are comparable results between the two techniques. For higher frequencies (3,4 kHz) differences in favor of stapedotomy are observed. Stapedotomy patients reach a difference of 10-20% in percentage of ABG closure when compared with stapedectomy for high frequencies.
Similar results are obtained if the postoperative ABG is used as measurement of
improvement. Comparable results, sometimes in favor of stapedectomy, are present for frequencies up to 2 kHz. ABG closure which is better between 5 and 15 dΒ is observed in 4 kHz in favor of stapedotomy.
Some studies use as a criterion the absolute difference of air conduction thresholds before and after the operation. Again in frequencies 4 kHz, 8 kHz the measurements are better between 10-15 dΒ for stapedotomy. It is quite interesting that bone conduction thresholds usually deteriorate in high frequencies in stapedectomy patients.
In terms of safety, results are also in favor of stapedotomy with sensorineural hearing loss or even deafness having a 2-3 times less relative risk to occur in comparison to stapedectomy. The same relative risk is present in postoperative vertigo/dizziness with stapedotomy being again superior.
It is worth mentioning that there is no relative literature comparing the two techniques over the last two decades. Stapedotomy is considered now the main technique for the surgical treatment of otosclerosis. Current literature mainly explores how stapedotomy could be improved in terms of effectiveness and safety by using sophisticated technology tools.
A number of different lasers has been used successfully in the surgical management of
otosclerosis demonstrating at the same time, an excellent safety profile. However, due to the variety of laser types options, it is extremely difficult to compare them in order to reach to specific conclusions with their use in otosclerosis.
In terms of safety, CO₂ laser is dominant in the otosclerosis related literature. CO₂ laser is superior to any other type of laser and to conventional instruments (microdrill-skeeter) as it presents less complications from inner ear (dizziness, hearing loss) and facial nerve. Diode laser follows in numbers of publications and it is also characterized by an excellent safety profile. Concerns regarding Thulium laser safety have been expressed in a prospective case series when compared with CO₂ laser. KTP laser, Argon, Er-YAG and YSGG laser share also an excellent safety profile but the number of publications on otosclerosis are minimal.
When it comes to effectiveness of the different types of lasers, the percentage of the patients in which an ABG closure less than 10% was achieved, this varied between 81% και 96.8%.
Most publications however ranged between 84 and 89%. If the ABG closure was used as the main outcome measurement, this varied between 3.1 and 14.86 dΒ in isolated series for all different types of laser (not including reviews or meta-analysis). These numbers are comparable to conventional stapedotomy.
CO₂ laser was superior to conventional stapedotomy in all series comparing the two methods by 1-4 dB in ABG closure and by 4-14% to the percentage of patients for which ABG closure <10 dΒ was achieved. CO₂ laser was also superior to isolated series versus Thulium laser, KTP laser and Er-Yag laser without the difference however to be statistically significant.
Diode laser gives practically the same comparable results with conventional stapedotomy (sυperior in ABG closure to conventional by 0.4 and 1.4 dΒ in two publications and inferior by 0.2 dB in a third publication) bearing however in mind that it seems more safe in complications from inner ear (dizziness, hearing loss).
There are two meta-analysis comparing laser stapedotomy (different types have been
included) with conventional stapedotomy. ABG closure <10 dΒ was achieved in 84.48% of laser patients versus 74.51% in patients with conventional stapedotomy in the first one
reaching statistical significance while in the second, results were marginally in favor of
conventional (74% versus 72.3%) with no statistically significant difference.
In both meta-analyses however laser assisted stapedotomy provides better safety profile when compared to conventional inner ear complications (tinnitus, dizziness, sensorineural hearing loss). These complications occurred in 4.28% of patients undergoing conventional versus 3% of patients undergoing laser assisted stapedotomy. Due to the limitations mentioned before, no conclusion of the specific preferable laser type could be extracted.
Endoscopic stapedotomy literature research could reach more definite conclusions as it requires only two groups – a conventional (microscope) stapes surgery group and an
endoscopic stapes surgery group. The enhanced field visualization and the possibility for the surgeon to see beyond the tip of the instrument are the main advantages of endoscopic stapes surgery while one hand instrumentation, lack of depth perception and difficulties in training junior otologists are the main disadvantages.
Results from different case series suggested an excellent safety profile and comparable results with conventional (microscopic) stapedotomy. In the highest quality available meta-analysis endoscopic stapedotomy seems to be superior to conventional by 2.6 dΒ in the mean ABG closure and by 1.33 dΒ when comparing mean air conduction postoperative thresholds. The clearest advantage however relates with the reduction of chorda tympani manipulations that result in 15.2% less possibility for dysgeusia. There were no differences to the mean operative time and postoperative dizziness.
In two more meta-analyses the conclusions were similar and again in favor of the endoscopic stapedotomy. Endoscopic assisted stapes surgery is here to stay and could be the main option for the surgical treatment of the conductive hearing loss associated with otosclerosis.
