Temporal bone histopathology of open mastoidectomy cavities

Histopathological and Inflammatory Features of Chronically Discharging Open Mastoid Cavities: Secondary Analysis of a Randomized Clinical Trial

Importance

Many patients with an open radical mastoid cavity experience therapy-resistant otorrhea. Little is known about the underlying histopathological substrate of unstable cavities and the correlation with treatment failure.

Objective

To study the histopathological and inflammatory features of chronically discharging open radical mastoid cavities and the influence of different treatments.

Design, Setting, and Participants

This secondary analysis of a randomized clinical trial was a histopathology study of tissue samples of a cohort of 30 patients with a chronically discharging open mastoid cavity. Samples were taken from the cavities, which were treated with either honey gel or conventional eardrops in a tertiary center between 2012 and 2013. Tissue staining was performed in May 2014; final computer analysis/correlation studies were performed in June 2016.

Main Outcomes and Measures

Differences of epithelial tissue coverage, infiltration of T cells (CD3, CD4, CD8) and macrophage (CD68, isoenzyme nitric oxide synthase, arginase 1) (sub-)populations, infection status, and the correlation with clinical presentation.

Results

There were 30 patients (24 [80%] male; mean [SD] age, 59 [14] years). Cavities were covered with either stratified squamous (keratinized) epithelium (n = 10), respiratory columnar epithelium (n = 9), or granulation tissue (n = 10). The presence of respiratory epithelium was associated with lower treatment success (posttreatment VAS improvement of 3.1 [95% CI, 0.5 to 5.8] for discomfort and 3.6 [95% CI, 0.2 to 6.9] for otorrhea in the group with granulation tissue coverage vs 4.9 [95% CI, 0.2 to 9.6] and 5.8 [95% CI, -0.1 to 11.6] in the group with squamous [keratinized] epithelium coverage and 1.4 [95% CI, -1.2 to 4.1] and 2.5 [95% CI, -1.3 to 6.2] in the group with respiratory columnar epithelium coverage). In all 3 tissue types of cavity-covering tissues, T-cell infiltrates consisted of helper T cells and cytotoxic T cells, together with a lower number of macrophages. The immunopositivity for isoenzyme nitric oxide synthase and arginase 1 was high and not restricted to a macrophage subpopulation, but seen in various cell types. Inflammatory infiltrations varied strongly in all 3 tissue modalities.

Conclusions and Relevance

Discharging open mastoid cavities can be classified histologically into 3 different types, based on their coverage: squamous epithelium, respiratory epithelium, or granulation tissue. Treatment is less successful in cavities covered with respiratory epithelium, possibly explained by the status of bacterial infection and local immunological differences.

Split-thickness skin grafting in postmastoidectomy revision and in lateral temporal bone resection

Objectives

Use of split-thickness skin grafts (STSG) in revision canal wall-down (CWD) mastoidectomy was compared with STSG in lateral temporal bone resection (LTBR).

Study Design and Setting

A retrospective study of 11 patients undergoing revision CWD mastoidectomy and 6 patients undergoing LTBR with STSG in an academic health center setting.

Results

Successful epithelialization of the mastoid cavity occurred in 9 patients (82%) undergoing CWD mastoidectomy. Subjective success, measured as reduction in complaints of otorrhea, occurred in 10 patients (91%). In the 6 patients who underwent LTBR and STSG successful epithelialization of the temporal bone defect occurred in 5 patients (83%).

Conclusions

Successful and rapid epithelialization occurred in the revision mastoidectomy cohort as well as in the primary temporal bone resection cohort.

Significance

Placement of STSG is a useful adjunct in revision CWD mastoidectomy as well as in primary LTBR for cancer.

Unique microbiology of chronically unstable canal wall down tympanomastoid cavities: considerations for surgical revision

OBJECTIVE

To review the microbiology of open tympanomastoid cavities in patients who underwent revision surgery due to chronic instability.

METHODS

This paper describes a retrospective chart review of surgical revision cases of chronically unstable open mastoid cavities. Patient records from 2000 to 2010 were reviewed for the type of organism cultured, antimicrobial resistance and the presence of cholesteatoma.

RESULTS

In total, 121 revision surgical procedures were performed on 101 patients. Seventy-nine procedures involved culture specimen processing, 37 of which were positive. The most commonly cultured organism was Staphylococcus aureus, which was more than twice as common as any other pathogen. The presence of cholesteatoma had no impact on the likelihood of a positive culture or polymicrobial culture. Antimicrobial-resistant pathogens were uncommon.

CONCLUSION

A positive culture was not an overwhelmingly common characteristic of unstable tympanomastoid cavities. Furthermore, antimicrobial resistance did not appear to play an essential role in leading patients towards revision open mastoid surgery.

Down-regulation of toll-like receptor 4 in the granulation tissues of postoperative mastoid cavities with otorrhea

CONCLUSIONS

The expression of toll-like receptor (TLR) 4 and associated downstream events, such as the activation of signal pathway proteins and inflammatory cytokine production, were down-regulated in the granulation tissues of postoperative mastoid cavity with otorrhea, possibly leading to endotoxin tolerance.

OBJECTIVE

The postoperative mastoid cavity is exposed to a high density and diversity of bacteria, but very little is known about how the immune environment is maintained in these regions with otorrhea. In this study, we investigated the changes in the TLR2 and TLR4 signaling pathways and inflammatory cytokine production in the granulation tissues of mastoid cavities with otorrhea and in normal auditory canal skin.

MATERIALS AND METHODS

We investigated the expression of TLR2 and TLR4, as well as downstream signal pathway proteins, nuclear factor-kappaB (NF-kappaB) DNA binding, and secretion of tumor necrosis factor-alpha (TNF-alpha) in 28 samples of granulation tissue obtained from the postoperative mastoid cavity with otorrhea and 10 normal external auditory canal skin samples.

RESULTS

We found that the frequency of TLR2- and TLR4-positive cells was not increased in granulation tissues relative to normal skin, but the TLR4 mRNA and protein were down-regulated. In this pathophysiological process, there was also a lack of downstream signal pathway protein activation and secretion of TNF-alpha.

Silent intratympanic membrane cholesteatoma

OBJECTIVE

To detect the presence of intratympanic membrane cholesteatoma in cases of chronic otitis media.

DESIGN

Two hundred forty-three temporal bones from patients with chronic otitis media were studied for the presence of intratympanic membrane cholesteatoma.

METHODS

Specimens had been previously removed at autopsy, fixed in 10% buffered formalin, decalcified in trichloroacetic acid, dehydrated in a graded series of ethanol, and embedded in celloidin. Sections were cut at a thickness of 20 microm, stained with hematoxylin eosin, and examined using light microscopy.

RESULTS

Intratympanic membrane cholesteatomas were found in five of the 243 temporal bones with chronic otitis media. All temporal bones with intratympanic membrane cholesteatomas were from adult patients. Two patients had bilateral intratympanic cholesteatomas in symmetric quadrants of the tympanic membrane, and the remaining patients with unilateral intratympanic membrane cholesteatoma had been operated on previously for a cholesteatoma of the opposite ear. Other common findings included chronic granulation tissue in the middle ears and mastoids, ossicular pathologic conditions, and in four of the five ears, fluid in the middle ears and/or mastoids.

CONCLUSION

When a white area is observed on the tympanic membrane of patients (especially those with "silent" chronic otitis media), differential diagnosis should include not only tympanosclerosis, but also intratympanic membrane cholesteatoma.

Epithelial migration in open mastoidectomy cavities

Twenty patients who had undergone open cavity mastoidectomy for chronic middle ear disease were selected for study. Following initial microscopic aural toilet, each cavity was painted in its medial aspect with a marker solution of Bonney's Blue dye. Each patient was assessed at weekly intervals for a minimum of three months following application of dye, and a photographic record made of the cavity. Information was also sought regarding the clinical behaviour of the mastoid cavities, with particular regard to degree of otorrhoea, and accumulation of debris. Migration of epithelium inferred by visible movement of dye occurred in 17 of the 20 mastoid cavities. In all these cases migration occurred in a medial to lateral direction, towards the exterior. In two cases there was no visible migration throughout the period of observation, and inspection after six months revealed the dye to be still present in the original position. Both these cases were of dry trouble-free cavities in which accumulation of debris did not appear to be a problem. This finding calls into question the assumption that clean trouble-free cavities are maintained by a satisfactorily functioning epithelial migration. In the four cavities which suffered from intermittent otorrhoea, epithelial migration occurred at a similar rate to that in dry cavities.