목적: Malleostapedotomy is a rare surgical procedure performed on patients with otosclerosis or congenital ossicular anomaly to enhance hearing and reduce air-bone gap in the absence of the incus long process. The loop of the malleus piston wire prosthesis (PWP) is usually hung up on the malleus handle while the other rod-shaped end is settled into the stapedotomy site. Because no malleus PWP is imported in Korea, patients have to prepare the malleus PWP by themselves before the surgery by going through a very complex cross-border shipping procedure under government approval. In this study, we aim to analyze the patients’ hearing gain from malleostapedotomy procedures using nitinol piston wires and to check for any complications after the surgery. Thanks to the shape memory effect of nitinol the crimping procedure is much easier resulting in a safer surgery. 방법:From 2021 to 2023, 13 patients underwent malleostapedotomy procedures using the nitinol piston wire prosthesis. The shape of the nitinol loop was fashioned to accommodate the unique oval and anterior angled shape of the malleus. The PWP had an offset axis of 15 degrees that correspond to the natural relationship between the malleus and stapes footplate. Among them 7 patients were female and 6 were male. Patient ages at the time of surgery ranged from 5 to 64 (20.8±19.0) while 8 of them were pediatric patients under age 11. Pediatric patients had an ossicular anomaly requiring ossiculoplasty to reduce the air-bone gap (n=8), sometimes for both ears (n=4). Non-pediatric patients were patients with otosclerosis (n=5). The mean follow up duration was 9.1±8.8 months. Pre and postoperative audiometry were compared to check the hearing gain. Also, any complications that occurred due to the surgical procedure were reviewed. 결과:The preoperative air-bone gap (ABG) was reduced from 46.7±7.55 dB to 19.5±7.38 dB after surgery for an average checkup time of 2 months. Word recognition scores (WRS) also increased by an average of 4.2±2.77% after 2 months. The loop closed automatically with a bipolar cauterization with a power of 7 mW or less. A 7 mm PWP were used for all patients except 2 who used 6mm PWP. No patient showed a sensorineural hearing loss or vertigo after surgery. There was no evidence of adverse reaction or infection during a mean follow up duration of 9.1±8.8 months (range 0.6 - 34.3 months). However, 1 patients had to go through revision surgery due to the misplacement of the PWP noticed during the outpatient clinic follow up. The piston was dislocated from the stapedotomy site. These postoperative problems were corrected by a single revision surgery. The chorda tympani nerve was preserved in all patients. 결론:Malleostapedotomy with nitinol PWP is a safe and effective treatment for patients with stapes fixation in the absence of incus long process. The angulation of the PWP and shape memory effect allowed easy surgery. The air-bone gap improvement was 27.2±9.93 dB and no deterioration found in this set of patients. Nitinol seems to be an biocompatible material in the middle ear with no evidence of adverse reaction. Revision surgery may be needed in 7.7% of patients but the problem was due to the anatomic factor of the patient and it was easily corrected with a single revision.