J Int Adv Otol 2016; 12(2): 152-5  • DOI: 10.5152/iao.2016.1575
Original Article
Comparison of Videonystagmography and Audiological 
Findings after Stapedotomy; CO2 Laser vs Perforator 
Sait Karaca, Oğuz Basut, Uygar Levent Demir, Ömer Afşın Özmen, Fikret Kasapoğlu, Hakan Coşkun
Department of Otolaryngology, Uludağ University School of Medicine, Bursa, Turkey
OBJECTIVE: Various types of laser, microdrill, and perforator are effectively used in the surgical treatment of otosclerosis. However, they have 
certain disadvantages along with advantages. The aim of this study was to evaluate the effects of carbon dioxide (CO2) laser and perforator stape-
dotomy techniques on audiological outcomes and postoperative vestibular functions via videonystagmography (VNG). 
MATERIALS and METHODS: This prospective and randomized clinical study was conducted in an academic tertiary medical center. Sixty-nine 
patients diagnosed with otosclerosis who underwent stapedotomy were enrolled in this study. Patients were divided into two groups based on 
the technique used in stapedotomy: CO2 laser and perforator. Postoperative hearing gain and VNG findings were the main outcome measures. 
Subsequently, the two study groups were compared for analysis. 
RESULTS: The preoperative air–bone gap was 32.7±8.9 decibel (dB) in the study population and it was improved to 12.9±8.4 dB after operation. 
There were no differences in VNG findings and vertigo symptoms between the laser and perforator groups at postoperative day 2. There was 
no significant gain difference regarding the air conduction, bone conduction, and air–bone gap between the two groups (p=0.294, p=0.57, and 
p=0.37, respectively).
CONCLUSION: Both CO2 laser and perforator stapedotomy have successful audiological outcomes with no difference in postoperative vestibular 
disturbance.
KEYWORDS: Otosclerosis, laser stapedotomy, vertigo, videonystagmography
INTRODUCTION
Since the first successful stapedectomy performed by Shea using teflon piston in May 1956, this surgery has been popular world-
wide. In early 1960s, Plester suggested the partial stapedectomy technique in which only portions of the footplate are removed [1]. 
Subsequently, partial stapedectomy technique has been improved and refined by Marquet [2], giving rise to a novel technique called 
as “stapedotomy,” which uses a small fenestra at the footplate.
Mechanical instruments were the only tools available to make a small fenestra at the footplate until Perkins first used an argon laser 
in stapedotomy [3]. Thereafter, other types of laser such as, carbon dioxide (CO2) laser, erbiyum yttrium aluminum garnet (Er:YAG) la-
ser, and potassium titanyl phosphate (KTP) laser, became available for middle ear surgery. Currently, surgical perforators, microdrills, 
and various types of laser are efficiently used in stapedotomy, although each technique has various advantages and disadvantages. 
Footplate fractures and sensorineural hearing (SNHL) loss were more frequent in conventional stapedotomy than in laser stapedot-
omy [4]. Recent data suggest that laser stapedotomy provides better hearing results compared to non-laser stapedotomy; however, 
subgroup analysis among the lasers was not available because of the lack of sufficient number of subjects [5]. In other studies, CO2 
laser had more favorable hearing outcomes than various other laser types [6, 7]. 
Stapedotomy may adversely influence vestibular functions. Postoperative symptoms of vertigo were reported between 27% and 
52% among different studies [8–11]. These symptoms usually subside within the early postoperative days, but very rarely, they may 
extend up to 6 months. Pressure and mobility changes in labyrinthine fluids, suppurative labyrinthitis, decrease of blood flow to the 
labyrinth, inner ear injury due to enzymatic process, and footplate complications are the proposed reasons for postoperative ver-
tigo [12]. Perilymphatic fistula and malposition or inappropriate length of prosthesis leads to the persistence of vertigo [13]. Sneezing 
and coughing increase the symptoms as they increase the perilymphatic pressure. We suggested that the technique used in stape-
dotomy may also influence postoperative vestibular symptoms. However, there are only very few studies that objectively evaluated 
the association between different techniques and vertigo via videonystagmography (VNG) [8–10].
Presented in: This study was presented at the 36th Turkish National Otorhinolaryngology and Head Neck Surgery Congress, 5-9 November 2014, Antalya, Turkey.
Corresponding Address: Uygar Levent Demir   E-mail: uygardemir@hotmail.com  
Submitted: 29.09.2015                Revision received: 31.03.2016                       Accepted: 01.04.2016 
152 ©Copyright 2016 by The European Academy of Otology and Neurotology and The Politzer Society - Available online at www.advancedotology.org
Karaca et al. Stapedotomy via using CO2 Laser vs Perforator
We argued that stapedotomy with a perforator may cause severe ver- Table 1. The demographic findings of patients
tigo compared to stapedotomy with laser because the former imparts   Total Laser Perforator p
direct trauma to the vestibule. Thus, the aim of this study was to assess Patient number 69 38 31 
the effects of CO2 laser and perforator stapedotomy techniques on au- Age 41.4±11.3 41.9±10.4 40.7±12.4 0.68
diological outcomes and postoperative vestibular functions via VNG 
and to compare the difference between these two techniques. Gender 
 Female  44 25 19 0.70
MATERIALS and METHODS  Male 25 13 12 
This prospective study was conducted between June 2012 and Janu-
ary 2014 at the Uludağ University School of Medicine, Department of Side
Otolaryngology. Sixty-nine patients diagnosed with otosclerosis who  Right  39 18 21
underwent surgery were enrolled in this study. Patients with congenital  Left 30 20 10 
nystagmus and a history of middle ear surgery were excluded. The pa- Follow-up  
tients were randomized into two groups according to the order of listing (months) 4±4.5 (1–28) 4.4±5.5 (1–28) 3.5±3 (1–12) 0.98
in the operation schedule as first one into laser stapedotomy and follow-
Patients who  
ing into perforator stapedotomy. Surgeons performed both techniques underwent VNG  38 19 19 
in equal numbers for randomization. Data including the intraoperative 
VNG: videonystagmography
findings, surgical technique, hearing outcomes, complications, vertigo 
symptoms, nystagmus, and VNG findings were retrieved. The study was 
approved by the ethical committee of Uludağ University School of Med- Table 2. The audiological findings in the laser and perforator groups
icine and written informed consent was obtained from each patient.  Perforator (n: 31) Laser (n: 38) p Total (n: 69)
Preop AC 55.4±11.4 59.6±15.9  57.7±14.1
All surgical interventions were performed under general anesthesia Postop AC 28.0±11.8 32.0±14.0 0.29 30.2±13.1
by senior surgeons using both techniques. Transcanal or endaural in-
cisions were used to reach the middle ear. After the suprastructure of Preop BC 22.2±10.2 27.3±11.4  25.0±11.1
stapes was removed, fenestration of the footplate was done either Postop BC 16.5±10.6 17.9±10.7 0.57 17.3±10.6
via CO2 laser at a 27-Watt single pulse mode on a scanner (Acupulse Preop ABG 33.2±8.2 32.3±9.6  32.7±8.9
40ST; Lumenis, Israel) or via a needle perforator manually. We used a Postop ABG 11.5±6.9 14.0±9.3 0.37 12.9±8.4
0.6-mm diameter teflon loop piston to reconstruct conduction be-
tween the footplate and incus. No oval window graft was used. Values are in dB±std dev. 
AC: air conduction; BC: bone conduction; ABG: air-bone gap
The patients were enquired for vertigo symptoms and examined for 
nystagmus during the early postoperative period. The hearing out- RESULTS
comes were assessed via postoperative changes in air conduction (AC), Of the 69 patients in the study group, 44 (63.8%) were females and 25 
bone conduction (BC), and air–bone gap (ABG) at frequencies of 0.5, 1, (36.2%) were males. Mean age of the study group was 41.4±11.3. The 
2, and 4 kHz (Intercoustics AC 40; Assens, Denmark). Postoperative ABG study group was divided into two different groups based on the surgi-
≤10 decibel (dB) was accepted as an outcome of successful hearing. cal technique used: the perforator group (n: 31) and laser group (n: 38). 
Mean follow-up duration was 4±4.5 months. There was no difference be-
We could perform VNG recording in only 38 patients, both on day 2 tween the perforator and laser groups with regard to age, gender, side, 
and at the first month after surgery (ICS CHARTR ENG/VNG 7.0.1 VNG; and follow-up duration (Table 1). Otosclerosis was present in 38 patients, 
Otometrics, Taastrup, Denmark). VNG recordings of the second post- tinnitus in 29 patients, and preoperative vertigo in two patients. In all, 38 
operative day consisted spontaneous nystagmus, gaze nystagmus patients of the study population underwent VNG recordings. Transcanal 
and positional nystagmus. At the end of the first month, we evalu- approach was used in 52 patients and endaural approach in 17 patients.
ated all the parameters of VNG including directional preponderance 
via caloric testing. Other 31 patients did not attend the testing ap- Audiological Findings
pointment at the first month. The slow phase velocity (SPV) limit was In the study population, preoperative BC, AC, and ABG were found to 
determined as 5 degrees per second. Maximal SPV value and direc- be 25±11.1 dB, 57.7±14.1 dB, and 32.7±8.9 dB, respectively, and post-
tion of nystagmus were considered as criteria for the assessment of operative BC, AC, and ABG were found to be 17.3±10.6 dB, 30.2±13.1 
caloric responses in the diagnosis of canal paresis and directional dB, and 12.9±8.4 dB, respectively. The comparative analysis between 
preponderance. the perforator and laser groups with regard to BC, AC, and ABG find-
ings is presented in Table 2. There was no significant difference be-
Statistical analysis was carried out using Statistical Package for Social tween the two groups in postoperative audiological findings (p=0.37 
Sciences (SPSS) v.22 (IBM Corp.; NY, USA). The comparisons of contin- for ABG, p=0.294 for AC, p=0.57 for BC). The distribution of postoper-
uous variables between discrete groups were done via the Student’s ative ABGs in the two patient groups is given in Table 3. 
t-test, if data was normally distributed and via the Mann-Whitney U 
test if not. The comparisons of categorical variables between discrete Vestibular Findings
groups were done via the Pearson Chi-square test. Level of signifi- Vertigo symptoms were observed in 11 patients who underwent laser 
cance was set at α=0.05. stapedotomy and in 13 patients in the perforator group on postoper-
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J Int Adv Otol 2016; 12(2): 152-5
Table 3. The distribution of air–bone gap (ABG) gains in the laser and abnormality in patients at the first month. The number of complications 
perforator groups and their distribution between the groups are shown in Table 6. 
Postop ABG Laser (n: 38) Perforator (n: 31)
0-10 dB 18 (47%) 17 (54.8%) DISCUSSION
11-20 dB 12 (31.5%) 14 (45.1%) The application of laser in stapedotomy has recently gained popular-
ity. Laser stapedotomy results in fewer footplate complications with 
21-30 dB 6 (18.4%) 0 better control during perforation [4]. Previous studies have shown 
>30 dB 2 (5.1%) 0 successful hearing outcomes using laser stapedotomy. Moscillo et al. 
[14]
Db: decibel; ABG: air-bone gap  compared the ABG closure between CO2 laser stapedotomy and 
conventional stapedotomy and indicated higher success rates in us-
[15]
Table 4. Videonystagmography and vestibular findings between the groups ing CO2 laser (90.6% vs 86%). In another study, Malafronte et al.  
at postoperative day 2 found ABG≤10 dB in 92% of patients who underwent CO2 laser stape-
dotomy and 90% of patients who underwent drill stapedotomy. In a 
 Perforator Laser p study by Motta and Moscillo, there was a significantly higher rate of 
Vertigo symptoms  13 (n: 31) 11 (n: 38) 0.26
successful ABG closure with CO2 laser compared with microdrill 
[16]. 
Spontaneous  A recent review comparing hearing outcomes between laser versus 
nystagmus at VNG 3 (n: 19) 0 (n: 19) 0.07 non-laser stapedotomy pointed out that laser surgery had signifi-
Gaze nystagmus at VNG 9 (n: 19) 9 (n: 19) 0.07 cantly better results [5]. We did not find a difference with respect to 
Positional nystagmus at VNG 4 (n: 19) 3 (n: 19) 0.68 ABG gain between the manual perforator and CO2 laser techniques. 
This finding may be due to lower success rates of hearing thresholds 
VNG: videonystagmography
via both techniques and low number of patients in our study.   
Table 5. The audiological findings in patients with or without postoperative Improvement in BC is another parameter of comparison between the 
vertigo laser and perforator stapedotomy groups. Kisilevsky et al. [17] indicat-
 Vertigo (+) (n: 24) Vertigo (-) (n: 45) p ed that bone conduction did not change following stapedotomy in 
Preop AC 55.3±13.2 60.0±14.6 0.20 a large series of primary cases. Moscillo et al. [14] did not show any dif-
Postop AC 27.4±13.5 31.7±12.8 0.14 ference in BC thresholds between the groups although both groups 
[18]
Preop BC 23.4±12.2 25.8±10.5 0.18 showed improvement. In a study by Brase et al. , better postopera-
tive BC threshold via laser stapedotomy was observed compared to 
Postop BC 16.0±12.7 18.0±9.4 0.25 manual perforator, but the difference was not significant. Similarly, 
Preop ABG 32.0±8.6 33.2±9.2 0.58 another study reported significant improvement in BC via laser com-
[19]
Postop ABG 11.4±6.5 13.7±9.2 0.50 pared to conventional stapedotomy . In our study, we found better 
Values are in dB±std dev. results in BC gain via laser compared to a perforator (9.4 dB vs. 5.7 dB, 
respectively), but there was no statistical significance. 
AC: air conduction; BC: bone conduction; ABG: air-bone gap
The association between the technique of stapedotomy and postoper-
Table 6. Postoperative complications in the laser and perforator groups ative vertigo remains controversial. Silverstein et al. [20] reported a high-
 Perforator Laser er incidence of postoperative vertigo in the laser stapedotomy group 
Floating footplate  4 1 compared to the conventional group (39% vs. 12%, respectively). 
However, in another study, there was no difference between these 
BPPV 1 2
groups in video-oculographic findings at postoperative week 1 [9]. 
Sensorineural hearing loss 1 - Similarly, we did not find statistical difference between two techniques 
Chorda tympani injury - 2 with regard to vertigo symptoms and objective findings in VNG. The 
Tympanic membrane perforation - 1 relation between the existence of postoperative vertigo and hearing 
improvement is another topic of debate. In their study, Aantaa and 
Persistent postoperative vertigo 1 1 Virolainen [8] showed that there was no association between hearing 
BPPV: benign paroxysmal positional vertigo outcomes and both the surgical technique and postoperative vertigo. 
Similarly, Birch and Elbrond [21] found that the presence of postopera-
tive vertigo had no influence on postoperative hearing levels. In an-
ative day 2 (p=0.26). We observed nystagmus in three patients in the other study, Ozmen et al. [22] reported no correlation between vestib-
laser group (n: 38) and in six patients in the perforator group (n: 31) at ular changes and audiological results via posturography. In our study, 
the early postoperative period (6 h after surgery) (p=0.16). VNG findings there was no association between the existence of vertigo and hearing 
on postoperative day 2 are shown in Table 4. There was no significant results, which is consistent with previous studies. 
difference between the laser and perforator groups with regard to the 
presence of spontaneous nystagmus, gaze nystagmus, and positional Benign paroxysmal positional vertigo (BPPV) is another cause of 
nystagmus (p=0.07, p=0.07, and p=0.68, respectively). The comparisons postoperative vertigo. Cupulolithiasis resulted due to manipulations 
of audiological outcomes between patients with or without vertigo on the footplate was suggested as the causative factor [23]. Atacan et 
symptoms revealed no difference (Table 5). VNG findings showed no al. [24] found significant difference in the incidence of BPPV in patients 
154
Karaca et al. Stapedotomy via using CO2 Laser vs Perforator
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financial support. [CrossRef]
26. Rangheard AS, Marsot-Dupuch K, Mark AS, Meyer B, Tubiana JM. Postop-
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