An evaluation of preoperative computed tomography on patients with chronic otitis media

Correlation of Preoperative High-resolution Computed Tomography Temporal Bone Findings with Intra-operative Findings in Various Ear Pathologies

High resolution computed tomography (HRCT) is a tool which provide fine details of temporal bone and its associated pathologies which are of extreme use in making diagnosis, to evaluate extension of disease and most important to plan surgical approach. Aim of the present study was to correlate HRCT findings with operative findings in different ear pathologies. This observational, prospective study enrolled 70 patients of different ear pathologies required surgical intervention. They were subjected to HRCT temporal bone and its findings were correlated with surgical findings. Mean age of the study population was 20.3 ± 12.04 years with M: F = 1.12: 1. HRCT showed specificity and sensitivity of 100% and 92.31% respectively in detecting ossicular erosion. It was 100% sensitive and 98.51% specific in detecting LSCC erosion, 85.71% sensitive and 96.83% specific in detecting facial canal dehiscence, 100% sensitive and 98.11% specific in detecting scutum erosion, 75% sensitive and 96.97% specific to detect tegmen erosion, 100% sensitive and 97.01% specific in detecting sinus plate erosion, 100% sensitive and 95.38% specific in detecting high jugular bulb, sensitivity and specificity both are 100% in detecting labyrinthitis ossificans and 100% sensitive in detecting otosclerotic foci. HRCT findings showed a good association with operative findings in terms of sensitivity and specificity. Thus, HRCT is a acceptable tool to make diagnosis and to plan surgical approach.

Prevalence of facial canal dehiscence and other bone defects by computed tomography

INTRODUCTION

The facial nerve is the most vulnerable structure during otological surgeries. Facial canal dehiscence (FCD) is the main risk factor for iatrogenic injuries. Its prevalence in clinical studies ranges between 6 and 33.3%, while anatomical studies report 25-57%. The objective was to determine the prevalence of FCD stratified by age and gender in a healthy population.

MATERIALS AND METHODS

Temporal bones from high-resolution computed tomography (CT) were analyzed. Patients with a history of trauma or tumors of the temporal bone, cholesteatomas, chronic middle ear disease, and any pathology that could modify the bone's anatomy, were excluded.

RESULTS

A total of 184 temporal bones were included. FCD was observed in 94 (51.2%) of the analyzed bones. The tympanic portion was the most frequently affected site with 91 (49.5%), followed by the mastoid segment with 3 (1.6%). No dehiscence was found in the labyrinth portion. We observed 30 (31.9%) of the FCD involved the oval window. Other bone defects identified with the FCD included: 11 (11.7%) with a lateral semicircular canal fistula and 7 (7.4%) with tegmen tympani erosions.

CONCLUSION

FCD has a high prevalence among healthy patients. A pre-surgical otological evaluation using high-resolution CT should be indicated to properly assess the patient and reduce the risk of injury.

Cautionary High-resolution Computed Tomography Findings for the Presence of Facial Canal Dehiscence in Patients with Cholesteatoma

Objective

This study aimed to investigate the abnormal high-resolution computed tomography (HRCT) findings in cholesteatomatous chronic otitis media (CCOM) patients preoperatively and the coexistence of abnormal HRCT findings with facial canal dehiscence (FCD) observed intraoperatively to identify the predictive factors associated with FCD.

Methods

The medical records of 151 CCOM patients who had undergone tympanomastoidectomy at our center were retrospectively examined in terms of the patients’ age and gender, preoperative HRCT findings [scutum defect, posterior wall of external auditory canal (PWEAC) defect, lateral semicircular canal (LSSC) defect, tegmen defect, and sigmoid plate erosion]. Operation records containing information about FCD were also analyzed.

Results

The prevalence of FCD was found to be 33.8% (51/151). There was a significant correlation between the presence of scutum, PWEAC, LSSC, and tegmen defects and the presence of FCD. However, no statistically significant correlation was found between the presence of sigmoid plate erosion and the presence of FCD. The results of regression analysis of the coexisting pathologic findings for FCD showed that the risk of FCD was highest in patients with LSSC + scutum defects (34.3-fold increase), followed by LSSC + PWEAC defects (31.6-fold increase).

Conclusion

Our study revealed that the presence of scutum, PWEAC, LSSC, and tegmen defects on HRCT indicates a higher risk of FCD preoperatively. This risk is even greater when multiple abnormal findings coexist.

Pre-operative prediction of cholesteatomas from radiology: retrospective cohort study of 106 cases

Objective

Pre-operative imaging is often used to predict the extent of a cholesteatoma and anatomical variation to plan for surgery. This study aimed to measure the predictive accuracy of computed tomography findings.

Methods

A retrospective cohort study was conducted of all patients in a district general hospital undergoing mastoid surgery within a consecutive 12-month period, in whom computed tomography had been performed prior to operative intervention. The study measured the key findings of pre-operative computed tomography imaging and compared them to the intra-operative findings.

Results

A total of 106 patients were included. The sensitivity and specificity for predicting cholesteatoma were 79 per cent and 81 per cent respectively. The positive predictive value was 90 per cent and the negative predictive value was 65 per cent. In predicting complications of cholesteatomas, the sensitivity was 70 per cent, whereas the specificity was 91 per cent. The positive predictive value was 88 per cent and the negative predictive value was 76 per cent.

Conclusion

Pre-operative computed tomography conducted prior to mastoid surgery has high positive predictive values for both predicting cholesteatomas and complications (90 per cent and 88 per cent respectively).

A Retrospective Study to Identify the Relationship Between the Dimension of Osseous External Auditory Canal and Chronic Otitis Media

Whether the dimension of the osseous external auditory canal (OEAC) is related to chronic otitis media (COM) remains an important but unresolved issue. In the literature, routine canaloplasty has been suggested to help elucidate this problem. In this study, we intended to investigate the relationship between the diameter or shape of OEAC and COM. We retrospectively reviewed the high-resolution computed tomography (HRCT) images of the temporal bones of 62 patients with unilateral COM who underwent tympanoplasty from January 1, 2011, to December 31, 2013. For comparison, the HRCT images of another 62 patients with normal ears were collected to be the control group. The shape of OEAC was categorized into 5 groups according to Mahboubi's classification, and the dimension of each patient's OEAC was measured at 2 defined sections (annular section and isthmus/midcanal section). The most prevalent shape of OEAC for the lesion sides of the ears was cylindrical, followed by conical, and hourglass in both the COM and the control groups. As to the dimension of OEAC, there were no significant differences between lesion ears and normal ears among patients in the COM group as well as between lesion ears in the COM group and normal ears in the control group. We concluded that the bony dimension of the external ear canal was not related to COM. This suggested that chronic inflammation or infection of middle ear may not cause bony thickening of OEAC, despite the kind of OEAC shape involved.

Is Routine Use of High Resolution Computerized Tomography of Temporal Bone in Patients of Atticoantral Chronic Suppurative Otitis Media without Intracranial Complications Justified?

Role of high resolution computerized tomography (HRCT) of temporal bone is established in cases of atticoantral chronic suppurative otitis media (CSOM) with intracranial complications. Routine use of HRCT in management of patients of atticoantral CSOM without intracranial complications has been an issue of debate. The aim of this study was to evaluate the routine use of HRCT of temporal bone in such cases. This study was a prospective study done at LG hospital, AMC MET Medical College, Ahmedabad to evaluate and compare the temporal bone findings in HRCT and intraoperative findings in 100 patients with atticoantral CSOM. All patients underwent HRCT screening followed by surgical exploration of middle ear cleft. In extent of disease HRCT showed very high sensitivity and specificity for epitympanum (100, 94%) and mesotympanum (98, 98%) areas. It gave valuable information of disease extent in hidden areas like sinus tympani and facial recess of mesotympanum. HRCT satisfactorily delineated malleus and incus erosion but had 75% sensitivity for detecting erosion of stapes suprastructure, though specificity was of 97%. For bony anatomical landmarks HRCT showed very high sensitivity and specificity for detecting erosion of lateral semicircular canal, tegmen tympani and sinus plate. Detection of facial canal erosion on HRCT had moderate sensitivity of 75%. We concluded that routine use of HRCT is justified as a reliable preoperative tool in patients with atticoantral CSOM without intracranial complications and it helps to plan type of surgical intervention. HRCT has limited role to distinguish between granulations and cholesteatoma and also to delineate stapes supra structure and facial nerve canal.

The changing epidemiological and complications profile of chronic suppurative otitis media in a developing country after two decades

To evaluate the shift in epidemiological and complication profiles of chronic suppurative otitis media (CSOM) over two decades in a resource-limited economy. A retrospective analysis of the prevalence of CSOM and its complications in tertiary health institution a over a period of 2 years were compared between 203 cases seen in 2009 and December 2010 (present era); and 343 cases seen in 1990 and 1991 (previous era). Data were collected on the demographic characteristics of the patients, age of onset of otorrhoea, the disease type, laterality and complications of CSOM. The prevalence of CSOM significantly reduced from 9 % in the previous era to 5.1 % in the present era (P < 0.0001). The mean age of the recent group was 27.6 ± 19.3 years, and was 21.6 ± 18.2 years in the previous group. (P = 0.009). Although both group had peak age prevalence at 11-20 years, recent group saw more significant adult population >20 years of age (P ≤ 0.001). More significant cases of cholesteatoma were documented in the recent group (3.4 %) than previous era (0.9 %) (P = 0.02). Although no significant change was noted regarding the rates of complication of CSOM in the two eras (P = 0.18), there was a notable shift toward predominant extracranial pattern of complication in the recent group (P = 0.04). The prevalence of CSOM has shown a significant reduction after two decades and it appears that there has been a shift in the epidemiology of CSOM towards a predominantly adult population in the recent years. Despite an overall reduction in the incidence of intracranial complications of CSOM in our series, its complication rates have not changed remarkably after 20 years.

Computed Tomography Staging of Middle Ear Cholesteatoma

Background

To establish computed tomography (CT) staging of middle ear cholesteatoma and assess its impact on the selection of the surgical procedure.

Material/Methods

Prospective study was conducted on 61 consecutive patients (mean age 26.8 years) with middle ear cholesteatoma. CT scan of the temporal bone and surgery were performed in all patients. CT staging classified cholesteatoma according to its location in the tympanic cavity (T); extension into the mastoid (M); and associated complications (C). Cholesteatoma was staged as stage I (T1, T2), stage II (T3, M1, M2, C1), and stage III (C2).

Results

The overall sensitivity of CT staging of cholesteatoma compared to surgery was 88% with excellent agreement and correlation between CT findings and intra-operative findings (K=0.863, r=0.86, P=0.001). There was excellent agreement and correlation of CT staging with surgical findings for T location (K=0.811, r=0.89, P=0.001), good for M extension (K=0.734, r=0.88, P=0.001), and excellent for associated C complications (K=1.00, r=1.0, P=0.001). Atticotympanotomy was carried out in stage I (n=14), intact canal wall surgery was performed in stage II (n=38), and canal wall down surgery was done in stage III (n=5) and stage II (n=4).

Conclusions

We established CT staging of middle ear cholesteatoma that helps surgeons to select an appropriate surgery.