Hearing Results with Clothespin Ossiculoplasty: Preliminary Report on the Kraus Modified Schuring Ossicle-Cup Prosthesis (Clothespin Prosthesis)

Abstract

The clothespin partial ossicular replacement prosthesis (PORP) is designed to Increase Joint stability during incus replacement ossiculoplasty. Fundamental modifications have been made in the Schuring ossicle-cup, which include a forked well, increased well wall thickness and length, and a flexible tip disk added to the shaft. The forked well functions like a straight clothespin rather than an inverted cup. The forked well enables the clothespin prothesis to slide down over the stapes superstructure, between the facial nerve canal and the promontory, to form a stable, mortise-and-tenon prosthesis-stapedial joint. Joint stability is enhanced because the inferior tine of the forked well is able to lever against the inferior surface of the stapes superstructure, creating a counterforce to gravity. This is in contrast to the more unstable ball-and-socket joint created by most partial ossicular replacement prostheses when they articulate with the stapes capitulum. The addition of a flexible disk to the shaft tip produces a tight, stable union between the prosthesis and the ossicular cap by increasing resistance at the shaft-ossicle interface. Fluoroplastic composition maximizes Intraoperative versatility and reliability while the ossicle cap minimizes extrusions. One-year hearing results for twelve chronic ear patients with mobile stapes undergoing clothespin ossiculoplasty during intact canal wall tympanomastoidectomy revealed postoperative air-bone gaps within 20 dB in 92% of cases. The mean postoperative air-bone gap was 8.9 dB, and the mean Improvement in air-bone gap was 14.4 dB. These results are attributable to greater prosthesis stability provided by the time-tested mortise-and-tenon joint concept rather than a ball-and-socket joint in a reconstructive situation in which stability is critical.