Stapedectomy 

Updated: Oct 24, 2018
Author: Rodney C Diaz, MD, FACS; Chief Editor: Arlen D Meyers, MD, MBA 

Overview

Background

History of Procedure

Hearing loss due to stapes fixation was first described by Valsalva in 1704 in his volume on the human ear.[1] It is unknown when the first attempts at stapes surgery were performed, although Kessel is credited as being the founder of stapes surgery in the 1870s.

Early attempts at stapes mobilization were fraught with complications, including fatal labyrinthitis, and provided hearing gain for only days. These results prompted leading otologists in 1899 at the Sixth International Otology Congress to declare stapes surgery useless, dangerous, and unethical,[2] thus ending further work on stapes mobilization procedures.

Following the turn of the 20th century, interest in surgery for stapes fixation was again reignited when Holmgren developed the fenestration procedure, in which a fenestra is created in the lateral semicircular canal, allowing sound to bypass the fixed stapes altogether. This was modified again by Sourdille in the 1930s, but it was Lempert who was credited with popularizing the fenestration procedure when, in 1938, he demonstrated a single-stage endaural fenestration procedure, which was quickly adopted as the procedure of choice for stapes ankylosis.

The current era of stapedectomy was started by Shea in the 1950s, when he created the first stapes prosthesis from Teflon. Various prostheses were then created during the following decade. The concept of stapes footplate surgery also changed, with various authors suggesting removing only portions of the footplate before placement of the prosthesis, and ultimately to the concept of the stapedotomy, in which a small hole is created in the fixated footplate for placement of the prosthesis. This allowed placement of the prosthesis piston into an appropriately sized hole and minimized the potential injury to the inner ear. Such techniques are still used today as the primary method of stapes surgery.

Indications

Indications and selection criteria for stapedectomy are as follows:

  • Reasonably good health to tolerate anesthesia, especially if general anesthesia is needed

  • Conductive hearing loss due to fixation of the stapes

  • Presence of an air-bone gap of at least 15 dB across 3 frequencies confirmed with tuning-fork testing

  • Good cochlear reserve as demonstrated by presence of good speech discrimination and adequate bone conduction thresholds, although this is not a universal requirement

    • Note: Stapedectomy does not treat sensorineural hearing loss (SNHL). A significant conductive component (as demonstrated by air-bone gap) is pertinent to patient selection especially when considering stapedectomy in patients with advanced otosclerosis (a patient with otosclerosis who has severely decreased speech recognition). Severe retrofenestral sclerosis and speech recognition scores of < 30% are associated with poor results.[3]

The ear with poorer hearing, based on the patient’s report rather than audiography, should undergo the operation first. In bilateral cases, the second ear can be operated on 6 months later, assuming this is now the poorer-hearing ear.

Contraindications

Contraindications to stapedectomy include the following:

  • Only hearing ear with serviceable hearing

  • Inner ear malformations (such as a large vestibular aqueduct and X chromosome-linked gusher)

  • Poor physical health

  • Current vertigo or balance problems such as active Meniere disease or especially in the case of superior semicircular canal dehiscence, in which the corresponding air-bone gap can potentially mimic otosclerosis

  • A fluctuating type hearing loss

  • Pre-existing tympanic membrane perforation

  • Active external or middle ear infection

  • An air-bone gap less than 15 dB across 3 frequencies

  • Lateral ossicular chain fixation (perform ossiculoplasty or mobilize lateral chain instead of stapedectomy)

Technical Considerations

Safe and effective stapedectomy requires a thorough knowledge of the anatomy of the middle ear and proper identification of anatomical variants if present. For more information, see Ear Anatomy.

Outcomes

Surgery is considered successful when the air-bone gap is closed to less than 10 dB across 90% or more of frequencies with improvement in air conduction by > 20 dB and bone conduction not worsened by more than 5 dB on postoperative audiography.

Large studies of thousands of patients who have undergone stapedectomy show that the success rate generally exceeds 95% for primary cases and 50%–70% in revision cases.[4, 5]  In two large-volume studies, patients reporting concurrent tinnitus had total resolution or decrease in intensity after stapes surgery.[6, 7]

The failure rate is approximately 5%–10% overall with stapedectomy, which most commonly results from prosthesis malposition. The second most common cause of failure is necrosis of the incus. Recent reports also suggest that patients with otosclerosis are at a higher risk of sensorineural hearing loss (SNHL) than hearing loss due to presbycusis.[8] The authors of this article suggest continued follow-up, as most patients who undergo this procedure ultimately require auditory rehabilitation or hearing aids.

Complications

Potential complications of stapedectomy include the following:

  • Tympanic membrane perforation

  • Floating or subluxed stapes footplate

  • Perilymph gusher

  • Facial nerve injury

  • Dysgeusia

  • Hearing loss

  • Vertigo

  • Failure of prosthesis/incus necrosis

  • Granuloma formation
  • Serous or suppurative labyrinthitis
  • Persistent Bleeding / Persistent stapedial artery

Tympanic membrane perforation

If a small perforation occurs during surgery, a fat or fascia myringoplasty or medial graft tympanoplasty can be performed to repair the defect intraoperatively, and stapes surgery can proceed. If a larger perforation is created or encountered, the safest choice is to perform tympanoplasty only and stage the stapedectomy to a subsequent procedure.

Floating or subluxed stapes footplate

This may occur during down-fracture of the stapes superstructure when the footplate can become separated from the annular ligament that attaches it to the oval window. If this occurs, the footplate may be completely pushed into the vestibule. If the footplate does enter the vestibule, the operation should be aborted and the oval window covered with fascia and the prosthesis placed. If the footplate is not completely submerged, it can be removed with small hooks if a pre-existing control hole was made prior to attempted footplate removal. Using a laser for stapedotomy can reduce the force placed on the oval window annulus; this can allow for stapedotomy to proceed or prevent this complication.[9] ​ 

Once retrieved, a fascial graft and the prosthesis can be placed. An alternative is to allow the footplate to become re-fixed and then return for the placement of the prosthesis later. No attempt should be made to remove a completely submerged footplate as this has high incidence of SNHL with attempted extrication.[9]

Perilymph (CSF) gusher

If the cochlear aqueduct is widely patent, there may be excessive perilymph flow once the fenestration has been created. In such cases, it is usually not noted until the footplate has already been opened or removed. Usually, the flow of fluid diminishes and stops.

The head of the bed should be immediately elevated if a gusher is encountered. A fascia plug that can underlie the prosthesis should be fashioned, and this should be held in place while the prosthesis is placed. In rare cases, a lumbar drain is necessary to reduce intracranial pressure sufficiently to stop the flow of perilymph. The middle ear and external auditory canal should also be packed to reduce flow as much as possible.

Use of preoperative imaging may demonstrate anatomic anomalies increasing risk of perilymph gusher such as a connection between the subarachnoid space and the perilymph or delineate an enlarged vestibular aqueduct.  

Facial nerve injury

The facial nerve is frequently dehiscent in its tympanic segment; however, this dehiscence is on the undersurface and rarely appreciated in most cases. If the dehiscent segment is sufficiently large, the nerve may prolapse and partially cover the footplate. If this is the case, the nerve may be gently retracted superiorly in order to expose the footplate and place the prosthesis. Generally, if the prosthesis must be bent to be placed, it will not provide a satisfactory hearing result. Additionally, when the nerve is dehiscent, extreme care must be used with the laser, as the heat damage from a direct hit with the laser can lead to a facial palsy.  A potential contraindication to stapedectomy can be an anomalous facial nerve that bifurcates around the superstructure, in which mobilization superiorly cannot be performed.[9]   

The facial nerve monitor may aid the surgeon by providing feedback during microdissection in the vicinity of the nerve but will not eliminate the risk of facial nerve injury. Facial nerve monitoring is only conducted in cases performed under general anesthesia and is not done in cases performed under conscious sedation.  

Dysgeusia

Transient dysgeusia is common (61.9%) after stapes surgery, however, the majority of these patients (95.8%) will recover within one year.24 Taste disturbances can result from injury to the chorda tympani. During the procedure, the chorda tympani is frequently in a position that obstructs a full view of the oval window. If this is the case, the nerve can be gently retracted superiorly or inferiorly. If, however, a significant stretch or partial tear develops, the nerve should be completely severed, since patients will have shorter-lived dysgeusia if the nerve is completely sectioned rather than partially injured. Some patients report of a metallic taste on the operated side if the nerve is cut.

Unilateral chorda tympani loss is usually not a devastating injury for patients; however, in patients who will undergo bilateral middle ear surgery, great care should be taken to ensure that at least one fully functional nerve remains. Patients in whom bilateral chorda tympani have been sacrificed can suffer from dry mouth and severe taste disturbances.

Hearing loss

Sensorineural hearing loss can result from damage to the cochlea during excessive manipulation of the stapes or inadvertent injury to the cochlea. The incidence of SNHL n stapedectomy surgery is low, with large studies reporting permanent SNHL of more than 15 dB at less than 0.5%.[10] This incidence is slightly more common in revision cases. Generally, the only therapeutic management in such cases is amplification with hearing aids in appropriate patients.

Vertigo

Vertigo can result from excessive manipulation of the stapes during surgery. This is slightly more common in revision cases and is ascertainable only if the patient is undergoing surgery under local anesthesia. If this occurs, the patient can be treated with intravenous droperidol and ondansetron to treat the vertigo.

During laser or mechanical stapedotomy, bone fragments may become mobile and fall into the vestibule, which may increase the chances of postoperative vertigo.  Any attempts at removal of such bony fragments from within the vestibule would potentially cause severe injury to the membranous labyrinth and thus should be avoided at all costs. Vertigo due to this mechanism is typically transient, clearing within one to two months of surgery.[9]

Postoperative vertigo  can also be caused by a prosthesis that is too long. This cause of vertigo is typically longer lasting and dose not resolve beyond two months postoperatively. If this is the case, the prosthesis should be removed and a shorter prosthesis reimplanted. Temporal bone CT has not been shown to be an accurate method of assessing piston depth within the vestibule.[11]  Therefore duration of persistent postoperative, true spinning vertigo alone should be the sole indicator driving clinical decision making on whether to revise and explant a potentially problematic stapes piston. 

Failure of prosthesis

Failure of the prosthesis most commonly results from an inappropriately measured and/or crimped prosthesis. Rarely, the crimping is too tight on the incus, leading to necrosis of the end of the incus long process and displacement of the prosthesis off of the incus. If this occurs, the prosthesis must be replaced in a modified fashion farther up on the incus long process or, occasionally, on the malleus manubrium.

Granuloma formation

A rare occurrence after primary prosthesis insertion (0.07%–5%), this cause of failure is not entirely understood but is thought to be a foreign body tissue reaction, with gelfoam and fat being the most commonly implicated substances implanted within the middle ear causing their development.[12]  

Serous or suppurative labyrinthitis

Another uncommon complication is suppurative labyrinthitis or other surgical site infection such as acute otitis media or meningitis following stapedectomy.  Prophylactic antimicrobial therapy has not been shown to reduce the incidence of this already rare complication.[13]

Persistent bleeding/persistent stapedial artery (PSA)

Initial injection of anesthetic agent with diluted epinephrine (1:100,000) normally provides adequate anesthesia and vasoconstriction to perform stapedotomy.  However, otosclerotic bone and overlying mucosa may be more hyperemic during the active phase of otospongiotic bone turnover. Bleeding during the procedure is usually controlled with topical application of epinephrine on a gelfoam sponge, and hemostasis is obtained prior to placing the stapes prosthesis to provide adequate view for proper placement.  

A persistent stapedial artery (PSA) (incidence 0.02%–0.48% in general population) may provide an additional challenge during stapes surgery and if not identified prior to surgical manipulation of the stapes can lead to brisk bleeding. A PSA can also be a mimic to otosclerosis audiometrically and cause a CHL by limiting the movement of the stapes. When the artery is small in size, it can be appropriately managed by cauterization with use of bipolar cautery or diffuse mode laser, and middle ear surgery can safely proceed.[14]  If a larger diameter PSA is encountered, it is best left in place until it is determined through angiographic studies not to be a critical branch in CNS circulation.[9]

 

Periprocedural Care

Pre-Procedure Planning

Preoperative evaluation

A thorough preoperative evaluation including a comprehensive physical exam should be performed to identify conditions that may present similarly to otosclerosis or may occur in conjunction with otosclerosis. For example, a history suggestive of a congenital dysplasia, as in the case of an enlarged vestibular aqueduct, or autophony, with accompanied sound induced vertigo, would be more suggestive of a semicircular canal dehiscence.

Otoscopy

Preoperative binocular microscopy should be performed and with inspection of the tympanic membrane to rule out evidence of atelectasis or cholesteatoma. Close inspection for the presence of myringosclerosis can point towards fixation of any of the ossicles.

Tuning fork testing

Rinne and Weber testing should be performed with 512 Hz (and optionally 1024 Hz and 2048 Hz) tuning forks to document conductive hearing loss.

Audiometry

Preoperative audiometry should be performed in all patients undergoing stapedectomy. Pure tone thresholds should be confirmed with tuning-fork tests prior to surgery for documentation of true hearing loss. Speech audiometry is important to document integrity of speech discrimination.

Immittance testing is necessary for all patients undergoing stapedectomy surgery. Acoustic reflex testing is a requirement, as the presence of intact acoustic reflexes must compel the surgeon to search for other causes of conductive hearing loss, such as superior semicircular canal dehiscence or other third-window fistulae

The usual pattern of otosclerosis is a normally shaped tympanogram with a large air-bone gap with absent stapedial muscle reflexes for both ipsilateral and contralateral stimulation. Occasionally, an A subtype S tympanogram may be identified, signifying normal tympanometry with decreased compliance in ossicular chain mobility. A Carhart notch, decreased bone conduction threshold at 2000 Hz, is typical and is indicative of otosclerosis. 

Preoperative imaging

Temporal bone CT can sometimes be used in preoperative analysis of oval window width and facial promontory angle to predict operative difficulty.[15]

However, in general, for primary procedures, preoperative imaging is not required for patients with a typical presentation of otosclerosis. Occasionally, CT scanning of the temporal bone can be useful for identifying anatomical variants (ie, dysplasia of the IAC or cochlea consistent with X linked gusher) that could pose problems during surgery or for possible factors that could explain surgical failure in revision operations.  

Equipment

Necessary equipment for stapedectomy includes a full set of middle-ear instruments with multiple sizes of otologic specula. Some surgeons use a speculum holder for steadying the speculum and freeing the hands for other instruments. Various blades, including a sickle knife and round knife, must also be available.

An operating microscope with a 200- to 250-mm objective is used for the entire procedure. Various microscopes are available with both fixed and adjustable focal lengths. The microscope is typically covered with a sterile drape for the procedure.

Recently, the endoscope has been used as an alternative approach to visualization during stapedectomy/stapedotomy. However, the mainstay of stapes surgery remains the transcanal approach utilizing the operating microscope. One study analyzed the audiological outcomes achieved by endoscopic surgery versus those with the microscope and showed similar hearing outcomes. However, the endoscopic approach required longer initial operative times. Challenges to stapes surgery with the endoscope include instrument limitation, single-handed work, lack of stereoscopic view, and a potentially high surgeon learning curve.[16, 17, 18]

Various methods are used for creating the fenestration in the stapes footplate. A Skeeter drill or microdrill has been used by some surgeons. Other authors suggest using a laser to minimize the vibrations caused by the drill on the stapes footplate, with a possible drop in bone conduction thresholds from sensorineural hearing loss at high frequencies due to acoustic trauma at the basal turn.[19] Multiple types of lasers have been advocated, including argon, KTP, and CO2 lasers.[20, 21, 22] Reports have shown no apparent difference between microdrill and the various laser techniques regarding drop in bone conduction thresholds.[23, 24, 25, 22, 26] Various modifications, including hand-held laser delivery devices (eg, Omniguide), are also available.

Potential damage to the membranous labyrinth due to the different absorptive properties of the various laser wavelengths in relation to the inner ear structures has caused some stapes surgeons to advocate for specific laser modalities over others. There are theoretical advantages to the use of the CO2 laser, due to its high reflectance off of the perilymph, versus the KTP and argon laser, which due to their lower wavelengths allow greater penetration into the perilymph and potentially greater energy absorption by the pigmented tissues of the membranous labyrinth in the line of laser fire at the base of the vestibule (ie, the saccule).[27]

When patients are under general anesthesia for the procedure, a facial nerve monitor is often used during the case. It is important to realize that the use of the facial nerve monitor does not eliminate the risk of facial nerve injury during stapedectomy. There is no substitute for a thorough knowledge of the middle-ear anatomy in order to avoid complications. The monitor can provide the surgeon with feedback while microdissection in the area of the facial nerve is performed, allowing the surgeon to modify technique to minimize risk of injury to the nerve. Electrodes are usually applied above the eye on the operative side within the orbicularis oculi muscle and above or below the lip on the operative side within the orbicularis oris. Grounding electrodes are placed in the forehead, upper chest, or shoulder.

Types of prostheses

Many types of prostheses exist for reconstruction in stapes surgery. Prostheses can be categorized as either hooked or handled prostheses.

Hook prostheses have shepherd’s crook–type open loops that hook around and are mechanically crimped or self-crimp around the incus, whereas handled prostheses have an articulating handle that swings above the incus to secure the incus lenticular process into a bucket-shaped hollow within the prosthesis shaft.

Self-crimping prostheses are made from nitinol. The wire of the prosthesis is made to the diameter of the incus; this will be stretched to the appropriate size for placement during surgery. When heated with a laser during surgery, it will return to its original diameter allowing for circumferential crimping of the hook without having to squeeze the incus with a manual crimper.[28]  

There have been few studies comparing the many available prostheses, and a true comparison of outcomes is not feasible due to outcomes being heavily dependent on experience of the operating surgeon. 

Patient Preparation

Anesthesia

Stapedectomy procedures are performed under either local monitored anesthesia care (MAC) or general anesthesia. Long-acting paralytics are not recommended owing to the inability to monitor facial nerve function.

The planned posterior canal skin incision area is typically infiltrated with lidocaine or bupivacaine (Marcaine) with diluted epinephrine. Some surgeons use diluted epinephrine (ie, 1:100,000) without anesthetic since injected solution sometimes migrates into the middle ear in the vicinity of the facial nerve, with resultant inability to monitor facial nerve function. Currently, however, no published literature supports the necessity of this practice.[29]

In patients who undergo surgery under MAC anesthesia, routine facial nerve monitoring is not required.

Approximately 2.5–3 mL of the anesthetic of choice is used. Injection is also performed at the vascular strip in order to reduce bleeding during the incision. Some surgeons also include an incision just anterior to the helical crus for improved exposure for the procedure.[30] If this is to be included, additional anesthetic should also be injected into this area.

Positioning

The patient is placed in the supine position on the operating table with the head turned to the opposite side from the operative ear, to about 30–45°. The head is held in place by tape placed across the patient’s forehead, securing him or her to the bed. The bed is almost uniformly turned 180° and the patient’s head positioned as close to the operating side as possible. The patient’s arms are tucked to his or her sides with adequate padding. Additionally, the patient is secured to the table with a waist band in case the bed must be rotated during the procedure.

Monitoring & Follow-up

Typically, patients are discharged home the same day following surgery.

Some patients experience vertigo or dysequilibrium after stapes surgery and should be counseled for this possibility during their preoperative evaluation. This is typically present for only several hours but may last up to several days and is almost always self-limited. Patients should be instructed not to blow their nose after surgery and to sneeze with an open mouth. They also should not strain themselves for a total of 2–4 weeks after surgery.

Patients are generally able to remove the cotton ball and Band-Aid from their ear after surgery the following day. If a Shaw disk is used, it is removed at their first follow-up, in one week following the procedure.

An audiogram is usually performed 3 weeks to one month after surgery, after most patients have regained their hearing. In the subset of patients in whom recovery is more slow, an audiogram repeated at 3–4 months can also be performed.

If the patient requires a revision surgery, it is usually not performed until 3–6 months have passed to allow time for full recovery. Hearing loss with a persistent ABG > 25 dB, persistent intractable vertigo, or facial nerve complication requiring intervention are the main indications for revision surgery.[12]

Patients should undergo annual audiography for the first 5 years after the procedure to ensure stability in hearing improvement.

The failure rate is approximately 5%–10% overall with stapedectomy, which most commonly results from prosthesis malposition. The second most common cause of failure is necrosis of the incus. Recent reports also suggest that patients with otosclerosis are at a higher risk of sensorineural hearing loss than hearing loss due to presbycusis.[8] The authors of this article suggest continued follow-up, as most patients who undergo this procedure ultimately require auditory rehabilitation or hearing aids.

 

Technique

Initial Approach

Once the patient is prepared and draped for the procedure, the operating microscope is brought into the field and used throughout the procedure. The povidone-iodine solution is irrigated out of the ear canal using warm saline and the tympanic membrane examined to ensure that there are no perforations.

The posterior canal incision is then created using a sickle knife or beaver blade.

If a standard posterior canal incision is made, it should be started at the 12 o’clock position about 3–4 mm from the annulus. This should then extend in a crescent from the 12 o’clock to the 6 o’clock position, extending to about 7-8 mm from the annulus along the posterior wall and swinging back toward the annulus to be within 3–4 mm at the 6 o’clock position. The flap should be slightly longer mid-flap than at either of the ends to ensure that the flap will reach the canal wall after some bone has been removed from the posterior scutum.

Other forms of incisions that can be used include the H flap, which involves a superior and inferior vertical incision at 12 o’clock and 6 o’clock and a connecting incision 7-–8 mm lateral to the annulus. In the modified H flap, the inferior vertical incision starts 1 mm from the annulus and is curved, starting from the vertical incision 8 mm lateral to the annulus and curving superiorly to the 12 o’clock position. Several clean passes with the knife are used to ensure that the cuts have progressed through the periosteum to the bone.

The tympanomeatal flap is then elevated with a wide elevator in a uniform manner toward the tympanic membrane. Care must be taken not to tear the flap as it is elevated.

Once the annulus is reached, the fibrous annulus is elevated off the bony annulus using a fine blade or needle such as a tab dissector or a Rosen needle. This is elevated in the inferior aspect of the incision to avoid inadvertent injury to the chorda tympani as it exits the bone.

Once the middle ear mucosa is identified, the middle ear is entered using the Rosen needle. The fibrous annulus is then fully lifted off the underlying bony annulus using a flap elevator such as Gimmick or the Rosen needle. This allows identification of the position of the chorda tympani nerve. The needle is then inserted superior to the nerve in a similar manner and carried anteriorly until it contacts the malleus. With the superior and inferior exposures obtained, the tympanic membrane is then separated from the chorda tympani, allowing anterior elevation of the tympanomeatal flap. Any bleeding at this stage is controlled with topical epinephrine.

In order to expose the oval window and the stapes, bone from the posterior scutum must be removed. This is accomplished with either a stapes curette or drill until the entire oval window can be visualized. If the beginning of the curve of the incus is visible, it could lead to a subsequent retraction pocket developing here, which should be avoided. The exposure should provide a view of the attachment of the anterior and posterior crura to the footplate, as well as the stapedial tendon from the pyramidal process to its attachment on the stapes. The surgical field is bordered in the middle ear by the round window niche inferiorly, the posterior scutal margin posteriorly, the Fallopian canal superiorly, and the malleus anteriorly.

At this point, the stapes and the remaining ossicular chain should be palpated to ensure that the stapes is indeed fixed. Once confirmed, a small, round right-angle knife is used to separate the incudostapedial joint. The intact stapedial tendon provides some resistance that can help avoid an inadvertent stapes subluxation. Small sawing or jiggling motions should be used to separate the joint, as strong direct pressure can lead to a dislocation of the incus as the joint separates. Once the joint is separated, palpation of the incus and malleus should reveal good mobility. Malleus fixation results in failure in hearing improvement despite a properly performed stapedectomy.  

The stapedius muscle tendon is then cut with scissors or the laser and any adhesions within the middle ear transected in order to completely free the stapes from any attachments. The stapes superstructure is then removed in any of numerous ways. Classically, a Rosen needle or other narrow-micro instrument is placed on the superior side of the stapes arch near the neck to swiftly down-fracture the anterior and posterior crura simultaneously. Another approach is to use a laser to vaporize the posterior crus near its attachment to the footplate and then to down-fracture the anterior crus in a similar fashion. In either case, most of the stapes superstructure should be removed to allow unobstructed placement of the prosthesis.

The distance from the incus to the fixed footplate is then measured. Most surgeons measure from the outer aspect of the incus and size the prosthesis accordingly. In most cases, the length from the outer aspect of the incus to the footplate is 4.5 mm but may range from 3.5 to 5.5 mm.

Stapedectomy Versus Stapedotomy

The classic description of a stapedectomy from this point is to completely remove the posterior and anterior portions of the footplate, leaving the membrane below the footplate intact. This is accomplished with various instruments angled appropriately to allow removal of the bone with preservation of the underlying membrane. Suction in this area is undertaken with great care as not to remove perilymph from the vestibule during this portion of the procedure. The oval window is then covered with a previously prepared piece of fascia or other tissue of choice to allow placement of the prosthesis over this.

The more recent modification and more commonly performed procedure is stapedotomy. In this procedure, the entire footplate is not removed; instead, a fenestration is created in the footplate to allow placement of a prosthesis within this. This has the theoretical advantages of reducing the risk of perilymph fistula from removal of the entire footplate and avoiding sensorineural hearing loss due to excessive manipulation of the footplate during removal in a stapedectomy. Studies have shown equivalent results for both techniques,[31, 32] with excellent long-term results for stapedotomy as well.[4]

Currently, stapedotomy is the treatment of choice for otosclerosis with stapes fixation, since it is both simpler and safer than stapedectomy. Complete removal of the footplate is now reserved only for select cases. 

With stapedotomy, once the stapes superstructure has been removed, a laser is used to create the fenestration in the footplate. This usually begins by focusing the laser on a vessel on the footplate in order to produce char that will allow the subsequent creation of a rosette of laser perforations. This initial step is necessary with the KTP or argon lasers, since the light is better absorbed by the hemoglobin pigment than the tissue of the footplate itself. The CO2 laser does not have the same requirement. The rosette is enlarged sufficiently to accommodate the prosthesis within the footplate. Perilymph that seeps through the fenestration can be removed carefully using a 24-gauge suction.

An alternative to using the laser for creating the fenestration is the microdrill. This has the benefit of developing a uniform fenestration; however, the noise created by this technique in a patient under local anesthesia is sometimes intolerable, and the patient should be warned of an impending loud noise so he or she is not startled.

Once the fenestration has been created and adequately sized, the distance from the incus to the footplate is measured and the prosthesis appropriately sized. Various prostheses types are available, ranging from the Richardson bucket handle prosthesis to the SMart nitinol-polytef piston. Regardless of the prosthesis used, it is used to reestablish continuity between the long process of the incus to the stapes footplate. Most of these use a hook that attaches over the incus with a piston that inserts into the fenestration. The SMart piston is crimped in place by the laser on the hook. Other devices are crimped using special instruments or a nonserrated alligator. 

Stapes surgery continues to evolve, and an even less invasive, implantless procedure has been described where removal of only the fixed anterior footplate is performed while maintaining ossicular continuity via the posterior crus.[33]

Once the prosthesis is in place, the mobility of the ossicular chain is tested. Adequate mobility is ensured, and there should be some perceptible movement of the round window noted when the chain is palpated. Once this is complete, small pieces of Gelfoam are placed around the prosthesis to ensure it remains in its proper place, and the tympanomeatal flap is laid back into position. Some surgeons use a Shaw disk to hold the flap in proper alignment. Surgeons may dress the canal incision with gelfoam followed by packing the ear canal with an antibiotic ointment for greater flap support. A cotton ball and bandage are placed over the conchal bowl for dressing.