In 1958, John J. Shea, Jr., revived the long abandoned concept of stapedectomy for the surgical treatment of otosclerosis.1 Unlike Blake and Jack earlier in this century, Shea covered the opened oval window with connective tissue and reconstructed the impedance transfer of the ossicular chain with a polyethylene prosthesis from the incus to the oval window. Like the pioneering work of Lempert and Rosen, Shea’s original surgical procedure was soon followed by many modifications of his technique. The common goal of all these subsequent stapes procedures is to restore the impedance transfer of the ossicular chain. Controversy for contemporary otosclerosis surgery is concerned primarily with the choice of surgical technique for bypassing the otosclerotic focus. It is our belief that there is no one correct way to perform stapes surgery for the treatment of otosclerotic stapes fixation. However, advances in instrumentation, particularly the introduction of microdrills and fiberoptic visible light laser hand pieces, have enabled surgeons to accomplish this goal in a more precise and delicate fashion.

Lasers in Otology

Stahle and Hogberg first proposed the use of surgical lasers for otologic surgery in 1965.² Unfortunately, this study and others using powerful pulsed lasers had distinctly chilling effects on early enthusiasm for otologic and neurologic laser surgery.^3–5 These studies demonstrated the devastating damage of pulsed lasers on the ear and brain. Unlike the –studies in biologic overkill” using pulsed lasers, an early study by Sataloff⁶ demonstrated the clinical potential of lasers in otosclerosis surgery. In 1967, using a neodymium-glass laser, Sataloff⁶ discretely fenestrated a cadaver stapes footplate. In 1979, Escudero et al.⁷ excited the otologic world by reporting the use of an argon laser in seven patients undergoing tympanoplasty. Perkins⁸ and DiBartolomeo and Ellis⁹ first reported the application of a surgical laser to clinical stapes surgery in 1980. Both DiBartolomeo and Perkins used the argon laser to create a small fenestra in the stapes footplate. Numerous reports have since outlined the use of argon, KTP-532, and CO₂ lasers for oto-sclerosis and other middle ear disorders.^10–31

While discussing the use of an argon laser in acoustic tumor surgery, Glasscock et al.,³² in 1981, pointed out the practical problems associated with microscope-mounted micromanipulator delivery systems, including increased working distance, decreased available light, the need to –bounce the laser off of small mirrors to reach inaccessible areas,” and the necessity of keeping one hand out of the operative field on the joystick of the micromanipulator. In 1986, we began to experiment with hand-held fiberoptic systems for the argon laser. The initial system consisted of a 200-μm fiber taped to a Rosen needle. In 1987, we developed several fiberoptic hand pieces for the argon laser. The hand pieces consist of a 200- m fiber housed in a 24-gauge graduated needle hand piece designed to be held and used in a manner similar to a traditional otologic instrument. Fiberoptic hand pieces have eliminated the practical problems described by Glasscock. Fiberoptic hand pieces for both argon and KTP-532 lasers have since been used in otosclerosis, middle ear, and acoustic tumor surgery.

Laser Safety

Laser damage to the inner ear structures or the facial nerve has been a concern since both before and after lasers proved clinically effective in otologic surgery. Silverstein et al.³³ reported adverse results in their first two cases using an argon laser fiberoptic hand piece. In a revision stapes procedure, their first patient developed a discrimination loss of 40%. In a second case, a total hearing loss resulted when a large granuloma of the tympanomeatal flap filled the middle ear and grew into the oval window.

In a study using model vestibules and thermocouples to monitor temperature changes, Lesinski and Palmer,¹³ questioned the safety of both argon and KTP-532 lasers in primary and revision stapes surgery. Lesinski and Palmer’s experimental model showed minimal (0.4°C) temperature elevations recorded by a large (0.5-mm) black thermocouple within a model vestibule with careful argon and KTP-532 laser stapedotomies but marked temperature elevations with direct laser irradiation of the thermocouple.

In 1992, we repeated the experiments of Lesinski and Palmer, using a model vestibule with a small (0.025-mm) silver thermocouple and a 200-µm optical fiber delivery system for an argon laser.³⁴ No significant changes in temperature within the vestibule were noted with vaporization of the stapes crura, footplate, or open vestibule. A temperature elevation was only obtained in an open vestibule when using a large thermocouple (0.5-mm) painted black and after saline was aspirated from the model vestibule. An interesting observation in our study was an 80°;C temperature elevation in a second thermocouple placed at the level of the facial nerve. Kodali et al.³⁵ recently performed a similar thermocouple study in the chinchilla and found no significant difference between fiberoptic KTP-532 and CO₂ lasers. These investigators concluded that there was no contraindication, in terms of thermal injury to the inner ear, for the use of a visible light laser with a hand-held probe delivery system as compared to the CO₂ laser for stapedotomy.

The safety of fiberoptic visible light laser use in an open vestibule is further implied by a recent series of publications on inner ear laser surgery. In 1990, Okuna et al.36 reported using the argon laser through the oval window after stapedectomy in guinea pigs and monkeys. These workers noted acute elevation of the supporting and sensory epithelium from the basement membrane in the irradiated area of the utricular macula. Two weeks after irradiation, the otoliths of the macula had disappeared; by 10 weeks, the entire macula had disappeared. In these experimental animals, there was no change in the structure of the membranous labyrinth, sensory epithelium of the cochlea or nonirradiated vestibular organs. Both Nomura et al.³⁷ and Anthony³⁸ have reported safe use of the fiberoptic argon laser for utricular macula ablation.

In the series of Anthony, 13 of 14 patients were treated without loss of auditory function with a power setting of 3.5 W for 0.5 s. In this procedure, the laser is directed at the utricule through a fiberoptic probe placed through the oval window. Anthony attributed the loss of auditory function in his one patient to opening the footplate in an ear with endolymphatic hydrops.

In summary, experimental data presented during the past decade do not support the concept of thermal damage to the inner ear using either argon, KTP-532, or CO₂ lasers. Clinically, the use of otologic lasers over the past two decades has proved safe and effective for the surgical treatment of otosclerosis as well as other otologic disorders.

Advantages of Lasers for Stapes Surgery

Early enthusiasm for lasers in stapes surgery was far from unanimous. In the discussion of Perkin’s first presentation, Frances Sooy cited Kaplan’s law, –When you give a kid a hammer, everything he sees needs pounding.”³⁹ Similarly, the fiberoptic argon laser hand pieces have been described as a gimmick and fad by more than one nationally recognized otologist. One may question whether surgical lasers are little more than technological bravado for an operation considered by many the quintessence of otologic surgery. We believe that surgical lasers offer several worthwhile advantages to the stapes surgeon. The most significant benefit is elimination of mechanical trauma. In our experience, the high-frequency notch occasionally seen after mechanical stapedectomy is avoided with use of the argon laser. The absence of mechanical trauma is particularly important during revision stapes. The small spot size of the CO₂, KTP-532, and argon lasers allows precise and controlled removal of both bone and soft tissue in the oval window. Finally, the CO₂, KTP-532, and argon lasers all have hemostatic qualities that virtually eliminate bleeding during fenestration of the stapes foot-plate. In our hands, we believe that these advantages have increased the speed, efficiency, and safety of the small fenestra stapes procedure.

From a practical point of view, the use of a fiberoptic hand piece avoids a cumbersome micromanipulator that must be attached to the microscope and increases the working distance from the surgeon to the operative field. The fiberoptic hand piece may be held similar to a traditional surgical instrument and avoids removal of the surgeon’s dominant hand from the operative field to control the joystick on the micro-manipulator. By moving the tip of the optical fiber closer or farther from the target, the power density may be changed instantaneously from a high-power density for cutting or vaporization to a low-power density for coagulation. Fiberoptic hand pieces can be used around corners by simple movement of the instrument in the surgeon’s hand rather than moving the entire micromanipulator/microscope system to a different visual axis or using micromirrors. Finally, the protective shutter may be left on the microscope at all times, and laser use is accomplished by turning on the system and attaching the fiberoptic hand piece. This avoids time-consuming micromanipulator calibration and testing.

Patient Selection and Evaluation

Although we believe that surgical lasers offer significant advantages to the surgeon, it is important to remember that a successful stapes operation is predicated on much more than the technique of footplate management. When asked to list the 20 fine points of otosclerosis surgery, J. Bernard Causse⁴⁰ related 9 of these 20 fine points to preoperative evaluation and patient selection. We feel that a brief review of preoperative considerations is important.

A family history of otosclerosis is helpful in making the diagnosis of otosclerotic stapes fixation, but it is not present in most patients, and it is not necessary to determine candidacy for surgery. A history of otitis media is important to elicit in order to anticipate lateral ossicular chain pathology. Patients with a history of fluctuating hearing loss, progressive hearing loss after head trauma, or congenital anomalies of the ear and head and neck, particularly in the young, should be considered for an associated inner ear anomaly. High-resolution computed tomography (CT) of the temporal bone is suggested for these patients. Large vestibular aqueduct syndrome frequently presents with a mixed hearing loss and is not improved with surgery. A large cochlear aqueduct or widened internal auditory canal suggests the possibility of a perilymph gusher, and these patients are best treated with hearing amplification.

Audiologic evaluation routinely includes pure tone air and bone conduction, speech testing, and impedance testing. A Carhart notch and absence of the stapedius reflex on impedance testing with a negative history of otitis media argues strongly for a diagnosis of otosclerosis. An on–off response on impedance testing implies partial stapes fixation and surgery should be deferred for complete fixation. Surgery need not be limited to patients with a very large conductive hearing loss. However, an average air–bone gap of 10 dB in the speech frequencies (500 to 3000 Hz) is considered a minimum for surgery. Patients with advanced otosclerosis resulting in a severe to profound mixed hearing loss can also benefit from stapedotomy. Closure of the air–bone gap in these patients greatly improves their ability to benefit from hearing amplification.

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