Ossiculoplasty with semibiologic and composite prostheses.

Abstract

The Lippy-modified Robinson prosthesis has been used for years in revision stapedectomy and has proved successful in reconstructing the absent lenticular process. When this technique fails, an ossicle cup prosthesis can be used. The ossicle cup and columella have been used for 20 years with continuing success. The advantages of the semibiologic prostheses are as follows: The prosthesis can be sized as each case requires, giving a variable height above the remaining stapes. The prosthesis is designed not to touch the promontory or facial nerve canal. The synthetic portion of the semibiologic prosthesis does not touch the tympanic membrane. An efficient perpendicular action is achieved from the tympanic membrane to the stapes footplate. The prosthesis remains in place during tympanic membrane movement. A stable dynamic joint is provided with the stapes capitulum (ossicle cup). A safe platform is provided that distributes the weight of the assembly prosthesis over the entire stapes footplate (ossicle columella). Although both semibiologic prostheses are used routinely for partial and total ossicular replacement, other troublesome and technically difficult ossicular reconstruction problems can also be solved by the adaptability of the synthetic portion of the prosthesis. Because the synthetic portion of the prosthesis can be modified by notching, shaping, and trimming, the following problems can be overcome: A laterally healed tympanic membrane can be reached by increasing the length of the synthetic shaft. In the absence of the stapes capitulum, the cup is notched in two places (180 degrees apart) to fit the shoulders of the remaining stapes. Remaining crura on the footplate can be bypassed by trimming the synthetic footplate to fit in between the crura. The stapes with a low profile can be utilized by increasing the length of the synthetic shaft. An abnormal stapedial tendon attachment to the stapes capitulum can be overcome with a single notch in the cup. An overhanging facial nerve can usually be bypassed by the narrow design of the ossicle columella. The future of ossiculoplasty will rest more on the solution of ancillary problems than on ossiculoplasty techniques. These troublesome ancillary problems include eustachian tube dysfunction, cholesteatoma control, mucosa regeneration, and fibrosis during the healing process. The self-correcting process of ossiculoplasty is an evolutionary process, and the small surgical steps taken are slowly incorporated into surgical principles. Incorporating a synthetic prosthesis within a natural or synthetic ossicle is a logical and evolutionary step in the science of ossicular reconstruction.