This is a prospective study that was carried out in Otorhinolaryngology department at Mansoura University Hospital.
This current study included forty patients with otosclerosis. Patients were allocated in two groups. Group A included twenty patients, who underwent classic stapedotomy operation under local anesthesia and fixation of the prosthesis using a drop of bone cement. Group B included twenty patients, who underwent classic stapedotomy operation under local anesthesia but without fixation of the prosthesis with bone cement just tightening of the prosthesis around the long process of the incus.
In the present study, twenty six of patients were females (65%) and fourteen were males (35%) with female to male ratio of 1.8:1. This ratio is approximately consistent with a large number of studies on otosclerotic patients in different populations.
In a study by Gupta et al, they had estimated a female to male ratio of 1.6:1. In study onTurkish otosclerotic patients by Ertugay et al, the female to male ratio was 1.4:1. Mahfudz reported a female to male ratio of 1.4:1. The same ratio was reported by Alharabi.
The study of Babighian, GG and Albu, S revealed that female to male ratio was 1.25:1. A different ratio was reported by Cordovés, AP et al, who found that 70.2% of patients were females and 29.8% were men with a ratio of 2.4:1. Another ratio of 2.6 female: 1 male was reported by Nemati et al.
In this current study, it has been found that the age of otosclerotic patients ranged from 20 years to 40 years with a mean value of 32.80 ± 5.44 in tested group and 31.0 ± 7.18 in control one. Gupta et al and Mahfudz support this finding by age of presentation of 31-40 years. Also, Ertugay et al reported the mean age was 37.77 ± 9.51 years and Nemati et al, found that the mean age was of 36.45 ± 10.84 years.
On the other hand, Babighian, GG and Albu, S reported a higher mean age of presentation with otosclerosis that reached almost 43.5 years. Also, Kuo et al had revealed that the mean age of otosclerotic patients was 42.81 ± 12.58 years. Cordovés, AP et al reported that most of patients were presented at the third to fifth decades of life.
In this current study, hypoacusis was the main complaint and was found in 100% of otosclerotic patients. Tinnitus was the second complaint in 50% of patients. Ertugay et al revealed the same percentage. Also, Cordovés, AP et al, had revealed that the most frequent symptoms were hypoacusis in 100% of patients, and tinnitus in 89.4%. Ayache et al had reported similar incidences of hearing loss and tinnitus in their patients. However, Nemati et al documented that 100% of patients had hearing loss, and 51.1% had tinnitus.
The hearing results in our study showed that there are significant statistical differences between the pre-operative and post-operative air conduction threshold and air-bone gap in both groups. However, in group A, There are significant statistical differences between the pre-operative and post-operative bone conductive thresholds only at 2000 Hz comparing to group B where there are no significant statistical differences between the pre-operative and post-operative bone conductive thresholds at 500-4000 Hz.
In group A, the mean pre-operative air-bone gap was 24.25 ±14.44dB, and the mean post-operative air-bone gap was 6.0 ±5.53dB after 1 month, 3.25 ±2.94 dB after 3 months and 2.50 ±3.03 dB after 6 months at 2000Hz. However, in group B, the mean pre-operative air-bone gap was 26.0± 11.65 dB, and the mean post-operative air-bone gap was 5.50 ±6.47dB at 2000Hz.
Kolo and Ramalingam reported the overall mean pre-operative air-bone gap was 43.14 ±6.82 dB, and the overall mean post-operative air-bone gap was 19.17 ±12.69dB.
Husban reported complete closure of the air-bone gap in 88% of cases. However, Saki et al reported that the post-operative air-bone gap was less than 10 dB in 63.9%, between 10 to 20 dB in 29.99% and more than 20 dB in 5% of cases.
Mahfudz had calculated the post-operative air bone gap by subtracting the pre-operative bone conduction threshold from the post-operative air conduction thresholds and the closure of air bone gap to within 10 dB was achieved in 74.3% of patients. However, Kos et al reported that this method tends to artificially improve the results leading to over closure of post-operative residual air-bone gap as the bone conduction threshold improves after surgery. In study of Kos et al, outcome of residual air-bone gap of less than 10 dB was achieved in 78.9% of patients.
Babighian, GG and Albu, S had reported that the main cause for revision stapedectomy is the incus necrosis. Also, Bajaj et al, documented that malcrimping of the prosthesis over the incus was the commonest cause for necrosis of the long process of incus leading to a residual air-bone gap.
Different types of stapes prosthesis and different types of adhesive materials were used to achieve a secure attachment to the incus. Singh and Goyal started by using titanium soft clip piston to avoid these problems and their results showed that the mean post-operative air-bone gap was within 10 dB in 40% of patients, up to 15 dB in 40% of patients and within 20 dB in 20% of patients.
In study of Baglam et al, bone cement was used to rebridge the incudostapedial joint and the post-operative air-bone gap less than 20 dB was achieved in 81.6% of patients.
In our study, bone cement was used in group A of patients to fix the prosthesis to the incus minimizing the possibility of incus erosion. There are significant statistical differences between the pre-operative and post-operative air conduction threshold and between the air-bone gaps. There is also significant statistical difference between the pre-operative and post-operative bone conduction threshold only at 2000 Hz.
Goebel et al reported that during exploration of 33 years old otosclerotic woman, the facial nerve was overhanging the oval window requiring crimping the piston. The prosthesis was lightly crimped to the incus followed by application of bone cement over the prosthesis fixing it in place.
During post-operative follow up of patients under study, two patients (10%) in group A and three patients (15%) in group B developed vertigo and vomiting. They were managed by intravenous fluid, corticosteroids, antivertiginous and antiemetic drugs. All patients improved after two days. In Hirvonen and Aalto study, 25% of the patients developed vertigo, 10% developed floating sensation and 10% developed unspecific dizziness.
In study of Albera et al, the most common cause of vertigo was the post-operative labyrinthine hydrops that respond to bed rest, oral antivertigenous drugs and a low sodium diet. Injectable antivertigenous and antiemetic drugs may be used. However in persistant vertigo or hearing loss, they recommended surgical exploration which may reveal a post-operative fistula, a slipped prosthesis or a long prosthesis.
In the current study, no cases of facial palsy or perforation of the tympanic membrane were recorded. Theissing reported that tears of tympanic membrane occur due to a thin atrophic membrane or inattention to elevation of the fibrous annulus during raising a tympanomeatal flap. In simple tears without loss of tympanic membrane tissue, gel foam may be used. However, a large defect should be repaired with adipose tissue from ear lobe.
Nuri Ozgirgin reported that the skin flap may be separated from the tympanic annulus. This usually occurs in inferior locations that require no repair. However, grafting may be needed in superior tears.
In study of Galindo et al, there were no significant differences between patients in whom the chorda tympani nerve were preserved compared with those in whom the chorda tympani were sacrificed during surgery. Disappearance of symptoms was evidenced in almost all patients one year after surgery.