CO2 laser stapedotomy safety: influence of laser energy and time on bone-conduction hearing levels

High fluence in laser stapedotomy aggravates transient subjective dizziness

BACKGROUND

Laser fenestration in stapedotomy has thermal effect to the vestibule.

AIMS/OBJECTIVES

To evaluate the role of energy density (fluence) in the severity of postoperative vestibular symptoms.

MATERIALS AND METHODS

The retrospective chart-review study included 84 patients with otosclerosis that underwent primary laser stapedotomy. Surgical outcomes, including nystagmus, and subjective vestibular symptoms during one-month follow-up, were compared between potassium titanyl phosphate (KTP) and CO2 laser. According to this study and literature, we assessed the relationship between laser parameters and the incidence of persistent vestibular symptoms lasting more than one week after surgery.

RESULTS

The KTP and CO2 laser group included 48 and 36 patients, respectively. Fluence was different between the KTP (637 J/cm2) and CO2 (141 J/cm2) laser (p < .001). The KTP group showed gradual decrease in dizziness during one-month observation period, while the CO2 group exhibited a steep recovery curve in the first postoperative week (9 and 4 d of duration, respectively). The incidence of persistent vestibular symptoms was correlated with both fluence (r = 0.80, p = .01) and spot size (r = -0.74, p = .01).

CONCLUSIONS AND SIGNIFICANCE

Appropriate setting of parameters with lower fluence is desirable for the efficiency and safety of laser stapedotomy.Abbreviations: ABG: air-bone gap; SD: standard deviation.

Revision Stapes Surgery

Purpose of Review

This review briefly covers the history of stapedectomy, discusses the indications and problems encountered with revision surgery, and provides case examples with solutions.

Recent Findings

Revision surgery is challenging and successful outcome even in the most experienced specialists is 45–71%, which is far less than that of primary surgery.

Summary

Careful evaluation of the reasons for reoperation, anticipation of the common problems, and patient education on reasonable expectations are all very important for success.

Hearing Results in 151 Primary Stapedotomies for Otosclerosis: The Effects of Using Different Audiologic Parameters and Criteria on Success Rates

OBJECTIVE

To describe the 151 hearing results of primary stapedotomy for otosclerosis using different criteria of success rates.

DESIGN

Retrospective case series of 151 patients with a diagnosis of otosclerosis and operated on by the same surgeon with the same technique, using a CO2 laser. Patients with revision surgery were excluded. The audiometric data were extracted from the patient files and divided into three groups: early postoperative follow-up (<1 mo after surgery), mid-term follow up (between 1 mo and 1 yr), and late postoperative follow-up (>1 yr).

RESULTS

The postoperative air-bone gap (ABG) was 10 dB or less in 45.2% in the mid-term follow up. For this same follow-up, ABG closure less or equal than 20 dB was achieved in 95.6% of cases. The lower percentage of patients with a postoperative ABG closure of less than or equal to 10 dB can be due to the high rate of bone conduction (BC) overclosure of 15.65%. The functional success described as an air conduction (AC) threshold less than or equal to 30 dB was achieved in 52.2% of patients. The mean speech reception threshold (SRT) in the mid-term follow up was 27.4 dB. The analysis of the data according to the Amsterdam Hearing Evaluation Plots (AHEPs) shows a success rate of 87% at early follow-up.

CONCLUSIONS

The success rate is mainly dependent on the definition and criteria as a measure of success. An analysis of the evolution of the BC is mandatory to avoid a false positive success rate when the ABG closure is used. Therefore, the use of the AHEPs would acquire additional information. The hearing outcome has also been based on the speech audiometry and the number of patients achieving an AC less than or equal to 30 dB as a more realistic measure of success. Our series confirms good long term hearing results achieved in stapedotomy surgery with the CO2 laser.

Conventional approaches versus laser CO2 surgery in stapes surgery: a multicentre retrospective study

PURPOSE

To analyze and compare surgical and audiological outcomes of conventional approaches versus laser CO2 surgery in stapes surgery.

METHODS

333 patients who underwent stapes surgery were enrolled in the study; the patient population was divided into three groups: group 1: 170 patients treated with conventional stapedotomy with manual microdrill (average age 49.13 years); group 2: 119 patients treated with conventional stapedotomy with electrical microdrill (average age 51.06 years); group 3: 44 patients (average age 50.4 years) who underwent CO2 laser stapedotomy. Intra-operative, postoperative outcomes and audiological results were investigated.

RESULTS

The average surgical time of laser CO2 surgery was longer than for other surgical procedures. No statistical differences emerged in post-operative abnormal taste sensation. There was also no difference in postoperative dizziness. Air-bone gap (ABG) went down from 29.7 ± 10 dB (group 1) and 27.32 ± 9.20 (group 2) to 10 ± 6.9 dB (group 1) and 10.7 ± 6.03 dB (group 2). In group 3 the preoperative ABG was lowered from 28.3 ± 10.1 to 11.8 ± 10.9, with a statistical difference in auditory recovery (p = 0.0001); The group of patients treated with laser CO2 showed a percentage of patients with an ABG closure of between 0 and 10 dB higher than in the group treated with manual microdrills (77.2% vs. 60%, respectively; p = 0.03).

CONCLUSION

Overall surgical results of CO2 laser and conventional stapedotomy are comparable without any significant difference; however, the group treated with CO2 laser appears to have a percentage of patients with an ABG closure 0-10 dB higher than the group treated using the conventional technique.

Evaluation of Audiological Results and Cochleo-Vestibular Subclinical Injury After CO2 Laser Stapedotomy

BACKGROUND AND OBJECTIVES

Evaluation of the effectiveness and safety of CO₂ laser stapedotomy, focusing on the audiological results, and on the surgical cochleo-vestibular trauma.

STUDY DESIGN/MATERIALS AND METHODS

Retrospective clinical trial on 38 patients with the diagnosis of otosclerosis, who underwent CO₂ laser stapedotomy between January 2015 and October 2019. Postoperative air-bone gap (ABG), mean air conduction gain, and postoperative changes of high frequency threshold were evaluated 1, 3, 6, and 12 months after surgery. Videoculography (VOG) was performed to assess the vestibular impairment preoperatively and 1 day, 1 week, and 1 month after surgery.

RESULTS

Postoperative ABG closure within 10 dB was obtained in 35 cases (92.1%), with a mean postoperative ABG of 4.4 dB and a mean air conduction improvement of 32.3 dB. No significant worsening of high frequency threshold was observed. Spontaneous nystagmus was found preoperatively in 5/38 patients (13.2%), 1 day after surgery in 13/38 patients (34.2%), 1 week after surgery in 12/38 patients (31.6%), and 1 month after surgery in 4/38 patients (10.5%). Positional nystagmus was found preoperatively in 12/38 patients (31.6%), 1 day after surgery in 25/38 patients (65.8%), 1 week after surgery in 22/38 patients (57.9%), and 1 month after surgery in 10/38 patients (26.3%). The occurrence of nystagmus did not always correlate with vestibular symptoms: after surgery, 10 patients (26.3%) experienced vertigo associated with dizziness, 8 patients (21.1%) suffered from dizziness without vertigo, and 14 patients (36.8%) showed nystagmus without any symptomatology. At 1 month after surgery none of the patients complained about vestibular symptoms.

CONCLUSION

CO₂ laser stapedotomy is a safe and effective technique, which allows to obtain good functional results with minimal perioperative cochleo-vestibular trauma.© 2021 Wiley Periodicals LLC.