Endaural Endoscopic Atticoantrotomy (Retrograde Mastoidectomy) using a Constant Suction Bone-drilling Technique

Bone treating technique causes great technical challenge for endoscopic middle ear surgery. To address this problem, we developed a constant suction bone treating technique in our department, called endaural endoscopic atticoantrotomy. Our technique is quite simple, but efficient.

All we need to do is only a simple modification, of the traditional microscopic electrodrill handpiece. The suction tube is soft and flexible and the lens of endoscope is also protected. Place the patient in a supine position with the head rotated to the Contra lateral side, then sterilize and drape the surgical field.

After removing cerumen from EAC with forceps, administer local anesthesia to the EAC by injecting 1%lidocaine with adrenaline at seven and 11 o'clock positions. Under the endoscope make a circumferential incision with a round knife from two to six o'clock position counterclockwise for right ear, approximately eight millimeters from the tympanic membrane. Raise the tympanomeatal flap, with a one millimeter diameter suction tube and a small piece of gauze soaked with adrenaline.

Under direct vision, make an inner cartilaginous incision with the scalpel at the 12 o'clock position from the previously made circumferential incision towards the meatus and through the stretched intercartilaginous incisura. Make another radial incision with the scalpel at the six o'clock position from the previously made circumferential incision towards the meatus. Raise the flap enclosed by the medial circumferential incision in the two radial incisions outward with a curette.

Check the exposure of the lateral wall of the attic and the posterior wall of the EAC. Place a self retaining retractor to widen the meatus of the EAC and hold the lateral based skin flap in place. Tailor the tube of a disposable venous infusion needle to make a soft suction tube which will be used in the bone drilling stage.

Make several side holes at its distal end with scissors. Cut a small section of the tube of a disposable infusion set to make an electrodrill shaft sleeve that will protect the lens of the endoscope during bone drilling. Fix the sleeve to the drill handle with a sterile transparent sticker.

Put the distal end of the soft suction tube into the tympanic cavity and connect the other end of the tube to a vacuum aspirator. Execute bone drilling in an inside-out direction, starting from the posterior part of the scutum. Instruct the assistant to irrigate the meatus of the EAC with saline continuously and remove the lateral attic wall by bone drilling if the lesion extends superiorly.

As an optional step, remove malleus and incus for the purpose of lesion removal and ossicular chain reconstruction. Perform an extended atticoantrotomy, if the lesion extends further into the antrum. The operative cavity of this patient after completion of the endaural endoscopic atticoantrotomy is shown here.

After checking the integrity, and mobility of the ossicular chain after lesion removal, harvest a large piece of tragus cartilage with perichondrium on both sides. On one side detach the perichondrium from the cartilage with a round knife, leaving the perichondrium on the other side to form a cartilage perichondrium graft and tailor the cartilage perichondrium graft for reconstruction. Use the cartilage perichondrium graft in the perichondrium to reconstruct the lateral wall of the attic, in the tympanic membrane.

Reconstruct the ossicular chain with various mature surgical techniques. Tailor and reposition tympanomeatal flap and the lateral based skin flap and pack the EAC with a gelatin sponge. Suture the Intercartilaginous incision, and pack it with gauze.

The endaural exclusive endoscopic atticoantrotomy was performed on 11 patients using the above mentioned constant suction bone drilling technique. The patient's characteristics are described here. Most of these cases were cholesteatoma, and the most common sites of involvement were attic.

Intra-operative ossicular chain reconstruction was performed using methods, including titanium partial ossicular replacement prosthesis, and titanium total ossicular replacement prosthesis. The results of short-term follow up seem promising. However, the results of long-term follow up are still unclear, with respect to the hearing outcome, a better postoperative air-bone gap, or ABG was observed in five patients.

No significant change was observed in ABG in five patients, and a worse post-operative ABG was noted in one patient. Post-operative facial nerve function was normal in all the patients. A representative axial CT image of one patient showed Cholesteatoma in the attic, and antrum.

The pre-operative endoscopic image of the tympanic membrane, before the operation is shown here. Endoscopic images of the tympanic membrane six months after the operation is shown here. One month after the surgery, the endaural incision was almost invisible.

This constant suction bone treating technique, and the endaural endoscopic atticoantrotomy beside, provide an endoscopic solution for various middle ear lesions, especially for cholesteatoma with different extensions. It can also be used to enlarge the posterior bony part of neo-canal, which is quite useful for some patients with ear canal stenosis.