Comparison of polydioxanone and silicone plastic in the prevention of adhesive otitis media in the Mongolian gerbil

Comparison of functional outcomes of cartilage tympanoplasty with silastic sheet versus Gelfoam packing in middle ear

BACKGROUND AND AIM

Tympanoplasty is a common surgery in otorhinolaryngology field. In majority of procedures, in addition to the graft used for closure of tympanic membrane, a packing material is essential to be placed in the middle ear cavity. The main goals of packing can be summarized as providing support to the tympanic membrane and ossicular grafts, aeration of middle ear cavity and hemostasis. Several packing materials are currently available for using in middle ear surgeries. Each agent is associated with particular advantages and disadvantages, so choosing the proper packing agent is essential in tympanoplasty surgeries. In this study we aimed to compare two common packing materials (Gelfoam and silastic sheets) in cartilage tympanoplasty surgeries.

METHODS AND MATERIALS

In this block-randomized clinical trial, 78 patients undergoing tympanoplasty in Vali-e-asr hospital in 2017 and 2018 were enrolled. They were randomly assigned to silastic sheet or gelfoam groups. The functional outcomes were compared between the groups. Statistical analysis was performed by SPSS.

RESULTS

Success was achieved in 32 (82.1%) patients and 34 (87.2%) patients in gelfoam and silastic sheets' groups, respectively (p = 0.530). The perforation area percentage was significantly lower (P = 0.007) in Gelfoam group. The other parameters were statistically the same in both groups (P > 0.05).

CONCLUSION

Overall, Gelfoam and silastic sheet methods had similar efficacy in cartilage tympanoplasty. Using each method depends on the preferrence of surgeon and patients' characteristics. Multi-center studies with larger sample sizes are needed for more conclusive results.

Prevention of Craniofacial Pain Secondary to Harvesting of Temporalis Fascia - A Novel Technique

OBJECTIVES

A lesser known after effect of harvesting temporalis fascia is the post-surgical craniofacial pain. The aim of the study was to evaluate this pain after tympanomastoid surgeries and the effectiveness of silastic sheet interpositioning to prevent this pain.

MATERIALS AND METHODS

This pilot study that spanned one year, included patients who underwent tympanoplasty with or without mastoidectomy involving the harvesting of temporalis fascia. At the end of surgery, the wound was closed after silastic sheet was secured over the donor site in cases and without silastic sheet in controls. In the post-operative period, patients scored their temporal pain, tenderness and pain during opening of mouth and mastication on a visual analogue scale (VAS) on day 7, 15, 30 and 90.

RESULTS

Visual analogue scale (VAS) scores of the silastic group were lower than the control group on day 7 and 15 after surgery and the difference was statistically significant. In the control group, temporal pain and tenderness were 74% and 81% respectively on day 7. VAS scores of both groups decreased over time and were negligible after 3 months. There were no significant postoperative complications in either group and no reaction or rejection of silastic sheet in the cases.

CONCLUSION

Post-surgical craniofacial pain secondary to the harvesting of temporalis fascia is observed in a majority of the patients. This novel technique involving silastic sheet interposition can decimate early post-operative temporal pain, tenderness and masticatory pain.

Antiadhesive effect of bioresorbable polylactide film in abraded middle ear mucosa

BACKGROUND AND OBJECTIVE

Polylactide film (PLF) is used to prevent postoperative peridural adhesion in spinal surgery. Up until now, the antiadhesive effect of bioresorbable PLF in ear middle surgery has not been reported. The purpose of this study is to evaluate the antiadhesive effect of PLF in guinea pigs serving as a model for middle ear mucosal trauma.

MATERIALS AND METHODS

The animals were divided into two groups: the PLF group and the silastic sheeting group. There were seven guinea pigs (fourteen ears) in both groups. Under aseptic conditions, the middle ear mucosa was abraded using a pick inserted transbullaly. A PLF or silicone sheet was then placed into the guinea pigs' middle ear cavities. The auditory brainstem responses (ABRs) were assessed preoperatively and at three weeks postoperatively while the animals were under general anesthesia. A histopathological study was performed 3 weeks after the operation.

RESULTS

The difference between the ABR results before the operation and three weeks postoperatively were not statistically significant. The adhesion formation did not appeared in either group. Prominent fibrous capsule formation and inflammation were observed in the silastic sheeting group, but not in the PLF group. Mild fibrous thickening of regenerated mucosa was observed in the PLF group.

CONCLUSION

From our results, bioresorbable PLF is nonototoxic and biocompatible with the guinea pig's middle ear cavity by short-term evaluation. Further long-term evaluation study is necessary before clinical application.

Systematic review of animal models of middle ear surgery

Animal models of middle ear surgery help us to explore disease processes and intervention outcomes in a manner not possible in patients. This review begins with an overview of animal models of middle ear surgery which outlines the advantages and limitations of such models. Procedures of interest include myringoplasty/tympanoplasty, mastoidectomy, ossiculoplasty, stapedectomy, and active middle ear implants. The most important issue is how well the model reflects the human response to surgery. Primates are most similar to humans with respect to anatomy; however, such studies are uncommon now due to expense and ethical issues. Conversely, small animals are easily obtained and housed, but experimental findings may not accurately represent what happens in humans. We then present a systematic review of animal models of middle ear surgery. Particular attention is paid to any distinctive anatomical features of the middle ear, the method of accessing the middle ear and the chosen outcomes. These outcomes are classified as either physiological in live animals, (e.g., behavioural or electrophysiological responses), or anatomical in cadaveric animals, (e.g., light or electron microscopy). Evoked physiological measures are limited by the disruption of the evoking air-conducted sound across the manipulated middle ear. The eleven identified species suitable as animal models are mouse, rat, gerbil, chinchilla, guinea pig, rabbit, cat, dog, sheep, pig and primate. Advantages and disadvantages of each species as a middle ear surgical model are outlined, and a suggested framework to aid in choosing a particular model is presented.

Insertion of middle-ear Silastic sheeting during tympanoplasty: hearing outcomes

Objective:

To study the effect of Silastic®sheeting placed in the middle ear during tympanoplasty, including the effect on hearing.

Design:

Retrospective study.

Background:

Chronic inflammation of the middle ear is common. Surgical treatment sometimes results in middle-ear adhesions and hearing deterioration.

Materials and methods:

We selected 106 patients with chronic otitis media, middle-ear adhesions and intact ossicles, based on intra-operative findings. These patients underwent single-stage tympanoplasty either with or without insertion of Silastic sheeting. Audiometry was undertaken pre-operatively and one and 12 months post-operatively.

Results:

Patients who had undergone Silastic sheet insertion showed significantly better air conduction, bone conduction and air–bone gap averages one year post-operatively, compared with those who had not.

Thickness of the gerbil tympanic membrane measured with confocal microscopy

Thickness data for the gerbil tympanic membrane, an extremely thin biological membrane, are presented. Thickness measurements were performed on fresh material using fluorescence images taken perpendicular through the membrane with a commercial confocal microscope. Thickness varies strongly across the membrane. Similar thickness distributions in all samples (pars tensa n = 11; pars flaccida n = 3) were observed. The pars tensa has a rather constant thickness of about 7 microm in the central region curving as a horse shoe upwards around the manubrium. In the most superior parts of the pars tensa thickness becomes gradually twice as large. Thickness increases also steeply from the central region towards the edges (about 35 microm near the annulus and 20 microm near the manubrium). A pronounced, local thickening of about 30 microm is present close to the edge and extends as a ring along the entire annular periphery of the pars tensa. Overall, the pars flaccida is thicker than the pars tensa and has a rugged surface. Its central region has a mean thickness of about 24 microm with a mean variation of about 4 microm. The average thickness in the inferior region is slightly larger than in the superior region. The pars flaccida thickens steeply, up to about 80 microm, near the edges.