Cartilage Interposition in Ossiculoplasty with Hydroxylapatite Prostheses: A Histopathologic Study in the Guinea Pig

Abstract

In this experimental animal study, a cartilage disk was interposed between a synthetic middle ear prosthesis and the tympanic membrane in guinea pigs to investigate its effect on the extrusion process of the implant. Two groups of guinea pigs were studied. One group consisted of animals in which the prosthesis was directly in contact with the tympanic membrane, and the other group consisted of animals in which a cartilage disk had been inserted between the head of the prosthesis and the tympanic membrane. Before histologic processing, in situ inspection was performed with an operating microscope. After fixation and embedding, light microscopic and transmission electron microscopic examination were performed. We studied the histopathologic aspects of the tympanic membrane with regard to the protrusion and extrusion processes of the middle ear implant. In this experimental model, protrusion and extrusion of a hydroxylapatite middle ear prosthesis was greatly reduced by interposition of a cartilage disk. Further clinical evaluation of these experimental results is needed in the human middle ear.

Results of inlay cartilage myringoplasty in terms of closure of central tympanic membrane perforations

“…9 In addition, the abnormal pressure of the graft may interfere with the blood supply of the tympanic membrane, resulting in avascular necrosis. 10 Cartilage contains type II collagen, whereas the predominant collagen in the tympanic membrane is type I. 11 The tympanic membrane is capable of mounting inflammatory and immune responses.…”

How Do Cartilage and other Material Overlay over a Prosthesis Affect its Vibration Transmission Properties in Ossiculoplasty?

“…4 Cartilage reduces extrusion rates very significantly even with the newer, more biocompatible hydroxyapatite and titanium prostheses, 5,6 an effect also demonstrated in animal models. 7 The insertion of cartilage at the interface with the eardrum may well change the vibration mechanics of the prosthesis. The size of cartilage cover is one of the few variables that the surgeon has control over during the ossiculoplasty.…”

“…Cartilage was crucial for the older Plasti‐Pore® prostheses, because of the otherwise high extrusion rate without its use 4 . Cartilage reduces extrusion rates very significantly even with the newer, more biocompatible hydroxyapatite and titanium prostheses, 5,6 an effect also demonstrated in animal models 7 . The insertion of cartilage at the interface with the eardrum may well change the vibration mechanics of the prosthesis.…”

Butterfly Cartilage Tympanoplasty as an Alternative to Conventional Surgery for Tympanic Membrane Perforations: A Systematic Review and Meta-Analysis

“…22 Heavier weight and pressure of the graft may tear the fibers and affect the blood supply of the TM, resulting in graft failure. 47 Hence, it is essential to precisely measure the size and shape of the perforation in relation to the size of the cartilage graft to reduce errors caused by inaccurate visual observation and judgment. 48 Importantly, a meticulous middle ear evaluation is necessary as the opacity of cartilage may hide diseases (eg, cholesteatoma) behind the TM 23 ; this could be assisted with an endoscope.…”