Objective: Three-dimensional printing technology is being employed in a variety of medical and surgical specialties to improve patient care and advance resident physician training. As the costs of implementing three-dimensional printing have declined, the use of this technology has expanded, especially within surgical specialties. This article explores the types of threedimensional printing available, highlights the benefits and drawbacks of each methodology, provides examples of how three-dimensional printing has been applied within the field of otolaryngology -head and neck surgery, discusses future innovations, and explores the financial impact of these advances.Data Sources: Articles were identified from PubMed and Ovid Medline.Review Methods: PubMed and Ovid Medline were queried for English articles published between 2011and 2016, including a few articles prior to this time as relevant examples. Search terms included: three-dimensional printing, 3D-printing, otolaryngology, additive manufacturing, craniofacial, reconstruction, temporal bone, airway, sinus, cost, and anatomic models.Conclusions: Three-dimensional printing has been used in recent years in otolaryngology for preoperative planning, education, prostheses, grafting, and reconstruction. Emerging technologies include the printing of tissue scaffolds for the auricle and nose, more realistic training models, and personalized implantable medical devices. Implications for Practice:After accounting for the upfront costs of three-dimensional printing, its utilization in surgical models, patient-specific implants, and custom instruments can reduce operating room time and thus decrease costs. Educational and training models provide an opportunity to better visualize anomalies, practice surgical technique, predict problems that might arise, and improve quality by reducing mistakes.3

Bone conduction is an efficient pathway of sound transmission which can be harnessed to provide hearing amplification. Bone conduction hearing devices may be indicated when ear canal pathology precludes the use of a conventional hearing aid, as well as in cases of single-sided deafness. Several different technologies exist which transmit sound via bone conduction. Here, we will review the physiology of bone conduction, the indications for bone conduction amplification, and the specifics of currently available devices.

Prior studies suggest that the use of facial nerve monitoring decreases the rate of immediate postoperative facial nerve weakness in parotid surgery, but published data are lacking on normative values for these parameters or cutoff values to prognosticate facial nerve outcomes. OBJECTIVE To identify intraoperative facial nerve monitoring parameters associated with postoperative weakness and to evaluate cutoff values for these parameters under which normal nerve function is more likely. DESIGN, SETTING, AND PARTICIPANTS This retrospective case series of 222 adult patients undergoing parotid surgery for benign disease performed with intraoperative nerve monitoring was conducted at an academic medical institution from September 13, 2004, to October 30, 2014. The data analysis was conducted from May 2018 to January 2019. MAIN OUTCOMES AND MEASURES The main outcome measure was facial nerve weakness. Receiver operating characteristic curves were generated to define optimal cut point to maximize the sensitivity and specificity of the stimulation threshold, mechanical events, and spasm events associated with facial nerve weakness. RESULTS Of 222 participants, 121 were women and 101 were men, with a mean (SD) age of 51 (16) years. The rate of temporary facial nerve paresis of any nerve branch was 45%, and the rate of permanent paralysis was 1.3%. The mean predissection threshold was 0.22 milliamperes (mA) (range, 0.1-0.6 mA) and the mean postdissection threshold was 0.24 mA (range, 0.08-1.0 mA). The average number of mechanical events was 9 (range, 0-66), and mean number of spontaneous spasm events was 1 (range, 0-12). Both the postdissection threshold (area under the curve [AUC], 0.69; 95% CI, 0.62-0.77) and the number of mechanical events (AUC, 0.58; 95% CI, 0.50-0.66) were associated with early postoperative facial nerve outcome. The number of spasm events was not associated with facial nerve outcome. The optimal cutoff value for the threshold was 0.25 mA, and the optimal cutoff for number of mechanical events was 8. If a threshold of greater than 0.25 mA was paired with more than 8 mechanical events, there was a 77% chance of postoperative nerve weakness. Conversely, if a threshold was 0.25 mA or less and there were 8 mechanical events or less, there was 69% chance of normal postoperative nerve function. No parameters were associated with permanent facial nerve injury. CONCLUSIONS AND RELEVANCE Postdissection threshold and the number of mechanical events are associated with immediate postoperative facial nerve function. Accurate prediction of facial nerve function may provide anticipatory guidance to patients and may provide surgeons with intraoperative feedback allowing adjustment in operative techniques and perioperative management.

Objective: To describe postoperative hearing outcomes following transmastoid (TM) and middle cranial fossa (MCF) approaches for semicircular canal dehiscence (SSCD) repair. Study Design: Retrospective review. Setting: Academic, tertiary referral center. Patients: Adults with SSCD who underwent repair between 2005 and 2019. Interventions: Pure tone audiometry pre-and postoperatively after SSCD repair. Main Outcome Measures: Change in air-bone gap (ABG) at 250 and 500 Hz, pure tone average (PTA), bone conduction (BC), and air conduction (AC) thresholds at 500, 1000, 2000, and 4000 Hz for patients undergoing TM and MCF approaches for SSCD repair. Results: The average change in BC PTA for patients undergoing TM (n¼ 26) and MCF (n ¼ 24) SSCD repair was not significantly different between the two groups. The first and final postoperative PTAs were recorded an average of 1.7 (range 0.30-3.0) and 29.1 (range 3.5-154) months postoperatively. For patients who underwent MCF repair, the average BC PTAs increased (þ) by 2.2 dB HL ( p 0.43) and 0.57 dB HL ( p 0.88) at the first and final audiograms respectively compared to þ1.27 dB HL ( p 0.53) and a decrease (À) of 0.57 dB HL ( p 0.63) for the TM group. The average changes in low frequency ABG for patients undergoing MCF repair were À4.7 dB ( p 0.08) and À6.9 dB ( p 0.15) at first and final audiograms respectively compared to À4.9 dB ( p 0.06) and À4.1 dB ( p 0.36) for patients who underwent TM repair. There was a high frequency hearing loss noted at 8000 Hz for the MCF (30.0 dB AE 18.7 preop; 41.7 dB AE 21.7 postop; p 0.01) and TM (32.1 dB AE 23.2 preop; 44.3 dB AE 29.6 postop; p 0.001) groups which persisted on long term follow up. Conclusions: Both TM and MCF approaches to SSCD repair can be performed with long-term preservation of hearing. ABGs were reduced in each treatment group but did not reach significance. A high frequency hearing loss (8000 Hz) may be expected with either approach.