Cartilage's Contribution in Otology: A Comprehensive Review of Its Role in Ear Surgery

This comprehensive review thoroughly examines the pivotal role of cartilage in otologic surgery, elucidating its multifaceted contributions to both cosmetic and functional outcomes. From reconstructing the external ear to reinforcing the tympanic membrane and restoring the ossicular chain, cartilage emerges as a versatile and resilient biological material with unique properties that make it an invaluable resource for otologic surgeons. The review explores the nuances of cartilage's applications in various surgical contexts, emphasizing its significance in promoting tissue regeneration and healing. The text delves into advancements in tissue engineering, biodegradable scaffolds, and 3D printing technology, pointing toward a future where more precise and personalized interventions may redefine the landscape of otologic surgery. The convergence of these innovations holds the promise of elevating the standard of care, minimizing complications, and improving the quality of life for patients undergoing cartilage-based otologic procedures. This synthesis of current knowledge and future possibilities provides a valuable resource for otologists, surgeons, and researchers in the dynamic field of otology.

Health-related quality of life after otologic surgical treatment for chronic otitis media: systematic review

Objective

This systematic review aims to describe the impact of otologic surgery as a treatment for chronic otitis media (COM) on the Health-Related Quality of Life (HRQoL) of adult patients.

Methods

A literature search was performed in PubMed, Scopus, Embase, and Web of Science until May 2023. Prospective studies including adult patients with COM (cholesteatoma) who underwent canal wall up mastoidectomy, canal wall down mastoidectomy, or tympanoplasty without mastoidectomy, with pre- and postoperative HRQoL measurements, were considered eligible. Questionnaire validation studies were excluded. The risk of bias and study quality were evaluated with a Quality Assessment Tool (for before-after studies with no control group). To assess the change in HRQoL, pre- and postoperative HRQoL values and absolute changes were extracted, synthesized, and presented in tables. Standardized mean differences (SMD) were calculated to enhance comparisons.

Results

Of the 720 studies identified, 16 met the inclusion criteria of this review. Different questionnaires were used throughout the studies. The CES and COMOT-15 were used in five studies and the ZCMEI-21 and COMQ-12 in three studies. All studies indicated statistically significant improvement in HRQoL from pre- to postoperative, measured with disease-specific HRQoL questionnaires. General HRQoL questionnaires did not show significant improvement. Calculated SMDs ranged from 0.24 to 6.99.

Discussion and conclusion

Included studies had low (n = 10) to high (n = 6) risk of bias and poor (n = 4), fair (n = 7) or good (n = 5) study quality. Surgical treatment positively impacts the HRQoL of adult COM patients with and without cholesteatoma. However, the clinical relevance of the reported changes is unknown due to the lack of minimal clinically important differences (MCID) or cut-off values in each questionnaire. Therefore, further research regarding the MCIDs of each questionnaire is needed. Future research should also report preoperative chief symptoms and indications for surgery to improve individual patient counseling.

SARS-CoV-2 in the Middle Ear-CovEar: A Prospective Pilot Study

In post-mortem analyses, SARS-CoV-2 was found in the middle ear of some, but not all, patients with COVID-19. It is not clear whether SARS-CoV-2 penetrated the ear passively post mortem, or existed in the middle ear of living patients during, and perhaps also after, infection. This study investigated whether SARS-CoV-2 can be found in the middle ear of living patients during ear surgery. Swabs from the nasopharynx, the filter connected to the tracheal tube and secretions from the middle ear were collected during middle ear surgery. All samples were tested for the presence of SARS-CoV-2 using PCR. History of vaccination, COVID-19 history and contact with SARS-CoV-2-positive individuals were recorded preoperatively. Postoperative SARS-CoV-2 infection was noted at the follow-up visit. Overall, 63 participants (62%) were children and 39 (38%) were adults. SARS-CoV-2 was found in the middle ear and in the nasopharynx of two and four CovEar study participants, respectively. The filter connected to the tracheal tube was sterile in all cases. Cycle threshold (ct) values of the PCR test were between 25.94 and 37.06. SARS-CoV-2 penetrated the middle ear of living patients and was found in asymptomatic patients. The presence of SARS-CoV-2 in the middle ear may have implications for ear surgery and can pose a risk of infection for operating room staff. It may also directly affect the audio-vestibular system.

Effects of Age on Delayed Facial Palsy After Otologic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVES

To report 4 cases of delayed facial palsy (DFP) after pediatric middle ear (ME) surgery and systematically review and analyze the associated literature to evaluate the effects of age on DFP etiology, management, and prognosis.

METHODS

Systematic review of PubMed, Cochrane Library, and Embase for articles related to DFP after cochlear implantation (CI) was performed. These articles were assessed for level of evidence, methodological limitations, and number of cases. Meta-analysis was performed to assess the effects of age on DFP incidence. Furthermore, a comprehensive list of all pediatric DFP cases after otologic surgery was assembled through a multi-institutional retrospective review and systematic review of the literature.

RESULTS

Twenty-nine articles fit the criteria for inclusion in the meta-analysis. The incidence of DFP after CI was 0.23% and 1.01% for pediatric and adult cases, respectively. This difference was statistically significant (P < .001, odds ratio 4.36). Twenty-three cases, adding to the 4 presented herein, were suitable for a comprehensive list. The mean age was 6.9 years. Average postoperative day of paresis onset was 5.4, with an average maximum House-Brackmann grade of 3.5. All patients obtained full facial recovery after an average of 23.5 days.

CONCLUSIONS

The systematic review demonstrates that DFP after pediatric CI is rare and occurs at a significantly lower rate than in adults, further supporting the viral reactivation hypothesis of DFP. The prognosis for pediatric DFP after otologic surgery is excellent, with a high rate of full recovery in a short time frame. However, steroid administration can be considered.

LEVEL OF EVIDENCE

IIa.

Aerosol Generation During Otologic Surgery

OBJECTIVE

To assess whether aerosol generation occurs during otologic surgery, to define which instruments are aerosol generating, and to identify factors that enhance safety in protection against airborne pathogens, such as severe acute respiratory syndrome coronavirus 2.

STUDY DESIGN

An observational prospective study on aerosol measurements during otologic operations recorded between August and December 2020.

SETTING

Aerosol generation was measured with an Optical Particle Sizer as part of otologic operations with anesthesia. Particles with a size range of 0.3 to 10 μm were quantified. Aerosol generation was measured during otologic operations to analyze aerosols during drilling in transcanal and transmastoid operations and when using the following instruments: bipolar electrocautery, laser, suction, and cold instruments. Coughing is known to produce significant concentration of aerosols and is commonly used as a reference for high-risk aerosol generation. Thus, the operating room background concentration and coughing were chosen as reference values.

PATIENTS

Thirteen otologic operations were included. The average drilling time per surgery was 27.00 minutes (range, 2.00-71.80 min).

INTERVENTION

Different rotation speeds during drilling and other instruments were used.

MAIN OUTCOME MEASURES

Aerosol concentrations during operations were recorded and compared with background and cough aerosol concentrations.

RESULTS

Total aerosol concentrations during drilling were significantly higher than background ( p < 0.0001, d = 2.02) or coughing ( p < 0.0001, d = 0.50). A higher drilling rotation speed was associated with higher particle concentration ( p = 0.037, η2 = 0.01). Aerosol generation during bipolar electrocautery, drilling, and laser was significantly higher than with cold instruments or suction ( p < 0.0001, η2 = 0.04).

CONCLUSION

High aerosol generation is observed during otologic surgery when drill, laser, or bipolar electrocautery is used. Aerosol generation can be reduced by using cold instruments instead of electric and keeping the suction on during aerosol-generating procedures. If drilling is required, lower rotation speeds are recommended. These measures may help reduce the spread of airborne pathogens during otologic surgery.

Hearing Results in 151 Primary Stapedotomies for Otosclerosis: The Effects of Using Different Audiologic Parameters and Criteria on Success Rates

OBJECTIVE

To describe the 151 hearing results of primary stapedotomy for otosclerosis using different criteria of success rates.

DESIGN

Retrospective case series of 151 patients with a diagnosis of otosclerosis and operated on by the same surgeon with the same technique, using a CO2 laser. Patients with revision surgery were excluded. The audiometric data were extracted from the patient files and divided into three groups: early postoperative follow-up (<1 mo after surgery), mid-term follow up (between 1 mo and 1 yr), and late postoperative follow-up (>1 yr).

RESULTS

The postoperative air-bone gap (ABG) was 10 dB or less in 45.2% in the mid-term follow up. For this same follow-up, ABG closure less or equal than 20 dB was achieved in 95.6% of cases. The lower percentage of patients with a postoperative ABG closure of less than or equal to 10 dB can be due to the high rate of bone conduction (BC) overclosure of 15.65%. The functional success described as an air conduction (AC) threshold less than or equal to 30 dB was achieved in 52.2% of patients. The mean speech reception threshold (SRT) in the mid-term follow up was 27.4 dB. The analysis of the data according to the Amsterdam Hearing Evaluation Plots (AHEPs) shows a success rate of 87% at early follow-up.

CONCLUSIONS

The success rate is mainly dependent on the definition and criteria as a measure of success. An analysis of the evolution of the BC is mandatory to avoid a false positive success rate when the ABG closure is used. Therefore, the use of the AHEPs would acquire additional information. The hearing outcome has also been based on the speech audiometry and the number of patients achieving an AC less than or equal to 30 dB as a more realistic measure of success. Our series confirms good long term hearing results achieved in stapedotomy surgery with the CO2 laser.

A Novel 3D-Printed Head Holder for Guinea Pig Ear Surgery

BACKGROUND

Otologic surgery in guinea pig requires head immobilization for microscopic manipulation. Existing commercially available stereotaxic frames are expensive and impede access to the ear as they rely on ear bars or mouthpieces to secure the head.

METHOD

Prototype head holders were designed using the Solidworks 2019 software and 3D-printed using Formlabs Form 2 Printers with photopolymer resin. The head holder consists of a C-shaped brace with adjustable radial inserts of 1/4-20 UNC standard screws with cone point tips providing head fixation for animals of various sizes. The C-shaped brace is attached to a rod that can be secured to a commercially available micromanipulator. The head holder design was tested during in vivo guinea pig experiments where their head motion with (n = 22) and without the head holder (n = 2) was evaluated visually through a stereotaxic microscope at 24× magnification during surgery.

RESULTS

The head holder design was easy to use and allowed for both nose cone administration of anesthesia and access to the ear for intraoperative auditory testing and manipulation. Functionally, the head holder successfully minimized head movement. Furthermore, harvested round window membranes evaluated at 72 hours following surgery showed precise perforations with the use of head holder.

CONCLUSION

The novel 3D-printed head holder enables simultaneous access for nose cone administration of anesthesia and surgical manipulation of the ear and brain. Moreover, it provides a modular, intuitive, and economical alternative to commercial stereotaxic devices for minimizing head motion during small animal surgery.

Pain Management Following Otological Surgery: A Prospective Study of Different Strategies

OBJECTIVES

The aim of this study was to prospectively assess pain and associated analgesic consumption after otological surgery comparing two prescription patterns.

STUDY DESIGN

A prospective nonrandomized consecutive cohort study.

METHODS

125 adult patients undergoing ambulatory otologic surgery-cochlear implantation and endaural middle ear surgery, were assigned (according to surgeon's preference) and prospectively studied in two arms: 1) acetaminophen 500 mg + ibuprofen 400 mg; 2) acetaminophen 500 mg + codeine 30 mg. Pain levels, medication dose, disposal patterns of opioids, and suspected side effects were evaluated.

RESULTS

All patients reported mild to moderate pain. There was a statistically significant reduction of pain from day to day, which was on average 0.26 lower than the day before. Sufficient pain control could be achieved with both drug regimens with no significant difference in pain levels. Only 50% of patients who were prescribed opioids used them. Additionally, the median tablet intake was 3 tablets while 10 to 20 tablets were prescribed. The majority of patients (97%) did not dispose of these drugs safely.

CONCLUSION

Adequate analgesia was achieved in both arms of this study. Pain control following otologic surgery with a combination of acetaminophen and nonsteroidal anti-inflammatory drugs is recommended unless contraindications or chronic opioid use are present. If opioids such as codeine (30 mg) are prescribed, the amount should be reduced as low as possible, such as five tablets, based on our studied population.

LEVEL OF EVIDENCE

Level 3-a prospective nonrandomized consecutive cohort study Laryngoscope, 2021.

Evidence of SARS-CoV-2 Virus in the Middle Ear of Deceased COVID-19 Patients

The presence of SARS-CoV-2 in the middle ear reveals the etiopathogenesis of otitis media in COVID-19, as well as an epidemiological risk during otologic examination and surgical procedures in COVID-19 patients. The study included 8 deceased patients with COVID-19. Tissue samples from the middle ear were subjected to virology, histopathology, scanning (SEM) and transmission (TEM) electron microscopy investigation. Ethmoidal mucosa samples were processed for virology analyses. qPCR resulted positive for 75% of nasal mucosa samples and 50% of middle ear samples. Ct values showed lower viral loads in middle ear samples. A proportion of 66.6% patients with positive results in the nasal mucosa showed positive results in the middle ear, and the subtype analysis of the complete genome sequences indicated B.1.1.7 lineage for all samples. In histopathological and SEM samples, no pathological aspects were identified. TEM revealed on the background of death critical alteration of cellular morphology, suggestive structures resembling SARS-CoV-2, goblet cells and immune cells. SARS-CoV-2 can be present in the middle ear of COVID-19 patients even if there is not clinical evidence of acute otitis media. Otolaryngologists could be particularly exposed to COVID-19 infection.

National Trends in Opioid Prescriptions Following Outpatient Otologic Surgery, 2005-2017

OBJECTIVE

To describe opioid stewardship in ambulatory otologic surgery from 2005 to 2017.

STUDY DESIGN

Descriptive study of US private insurance claims.

SETTING

Nationwide deidentified private insurance claims database (Clinformatics DataMart; Optum).

METHODS

A total of 17,431 adult opioid-naïve outpatients were included in the study. Patients were identified from CPT-4 codes (Current Procedural Terminology, Fourth Edition) as having undergone middle ear or mastoid surgery. Multiple regression was used to determine sociodemographic and geographic predictors of postoperative morphine milligram equivalents (MMEs) prescribed, including procedure type, year of procedure, age, sex, education, income level, and geographic region of the United States.

RESULTS

The mean prescribed perioperative dose over the examined period was 203.03 MMEs (95% CI, 200.27-205.79; 5-mg hydrocodone pill equivalents, 40.61). In multivariate analysis, patients undergoing mastoid surgery were prescribed more opioids than those undergoing middle ear surgery (mean difference, 39.89 MME [95% CI, 34.37-45.41], P < .01; 5-mg hydrocodone pill equivalents, 8.0). Men were prescribed higher doses than women (mean difference, 15.39 [95% CI, 9.87-20.90], P < .01; 5-mg hydrocodone pill equivalents, 3.1). Overall MMEs prescribed by year demonstrates a sharp drop in MMEs from 2015 to 2017.

CONCLUSION

While the amount of opioids prescribed perioperatively has declined in recent years, otologists should continue to be cognizant of potential overprescribing in light of previous studies of patients' relatively low opioid intake.

Pros and Cons of the Exoscope for Otologic Surgery

Introduction. There are a few discussions regarding usefulness of an exoscope in otologic surgery compared to a traditional microscope. Objective. The pros and cons of using a newly developed exoscope (ORBEYE™) during microotologic surgery were evaluated. Methods. The usefulness of the ORBEYE™ exoscope was retrospectively assessed in 6 otologic surgeries by 8 surgeons postoperatively. A questionnaire comprising 20 questions was designed and used for evaluation. Results. All the otologic surgeons agreed that the exoscope is useful as an educational tool; the exoscope had the highest score in the questionnaire (average: 4.75). The question "Will the ORBEYE^TM exoscope replace the conventional tympanoplasty or stapes surgery?" had the lowest score (average: 3.13). Conclusions. The quality of the images and movies in the exoscope was considered to be high and improved; therefore, the exoscope was considered as a useful educational tool in otologic surgery. Similar to otologic endoscopic surgery, all the members such as the operator and assistants could head up and share 1 image.

Cadaveric Simulation of Otologic Procedures: An Analysis of Droplet Splatter Patterns During the COVID-19 Pandemic

Objective

The otolaryngology community has significant concerns regarding the spread of SARS-CoV-2 through droplet contamination and viral aerosolization during head and neck examinations and procedures. The objective of this study was to investigate the droplet and splatter contamination from common otologic procedures.

Study Design

Cadaver simulation series.

Setting

Dedicated surgical laboratory.

Methods

Two cadaver heads were prepped via bilateral middle cranial fossa approaches to the tegmen (n = 4). Fluorescein was instilled through a 4-mm burr hole drilled into the middle cranial fossa floor, and presence in the middle ear was confirmed via microscopic ear examination. Myringotomy with ventilation tube placement and mastoidectomy were performed, and the distribution and distance of resulting droplet splatter patterns were systematically evaluated.

Results

There were no fluorescein droplets or splatter contamination observed in the measured surgical field in any direction after myringotomy and insertion of ventilation tube. Gross contamination from the surgical site to 6 ft was noted after complete mastoidectomy, though, when performed in standard fashion.

Conclusion

Our results show that there is no droplet generation during myringotomy with ventilation tube placement in an operating room setting. Mastoidectomy, however, showed gross contamination 3 to 6 ft away in all directions measured. Additionally, there was significantly more droplet and splatter generation to the left of the surgeon when measured at 1 and 3 ft as compared with all other measured directions.

[Our first experience with endoscopic ear surgery]

INTRODUCTION

For the last decades endoscopic ear surgery has become a common practice. Advantages of the endoscopic technique in middle ear surgery are high definition and magnification of the endoscope with a modern camera and the ability to 'look around the corner' with the angled scope.

MATERIAL AND METHODS

From March 2017 to November 2019 in NSRC PHOI named after Dmitry Rogachev in the Department of Oncology and Pediatric Surgery 53 patients (81 surgeries) have undergone endoscopic-assisted ear surgery: 3 biopsies for middle ear neoplasm with the transcanal endoscopic approach, 1 endoscopic tympanoplasty for attic retraction pocket with cholesteatoma, 2 endoscopic removal of middle ear tumors (including 1 combined approach) and 32 endoscopic myringoplasties, 22 canal wall down mastoidectomies for extensive middle ear and mastoid cholesteatoma, 21 second-look surgery with ossiculoplasty with overall good outcome. Age of the patients varied from 2 months to 16 years. Follow up period varied from 1 month to 3 years.

RESULTS

Two cases of middle ear tumor removal via endoscopic transcanal approach are described. In one case endoscopic transmeatal approach was used as an addition to the middle fossa approach for removal of facial nerve neurinoma located on the upper surface of petrous bone with expansion to the middle ear cavity. In the second case endoscopic transmeatal approach was used alone for removal of benign tumor (salivary gland choristoma) of middle ear cavity with extension to pneumatic system of petrous bone. In both cases endoscopic approach allowed to biopsy the tumor first and then to remove the tumor in a less invasive way, which lead to faster patient recovery.

CONCLUSION

In the majority of cases endoscopic technique is a method of assistance in otologic surgery, but sometimes could be a used a single method in middle ear surgery, allowing less traumatic approach and the implementation of high-definition camera for more precise disease control. In our preliminary experience endoscopic technique could be used in pediatric practice independently of the patient's age.

The Effect of Nasal Septal Deviation on the Postoperative Hearing Results of Patients With Tympanosclerosis

OBJECTIVE

The main aim is to discuss the effect of nasal septal deviation on the postoperative hearing results of patients with tympanosclerosis.

MATERIAL AND METHODS

We analyzed the hearing results of patients with tympanosclerosis who were operated on in a tertiary center. Pure tone audiometric results were compared according to the existence of nasal septal deviation.

RESULTS

This study included 48 patients with unilateral tympanosclerosis disease. Moderate or severe septal deviation had no significant effect on postoperative hearing results.

CONCLUSION

The nasal septal deviation as the only pathologic factor in patients with tympanosclerosis did not have a deteriorating effect after surgery.

Failure to close the gap: Concomitant superior canal dehiscence in otosclerosis patients

OBJECTIVE

Superior semicircular canal dehiscence (SSCD) causing conductive hearing loss with present reflexes is a known reason for stapes surgery failure. However, concomitant SSCD and otosclerosis occur rarely. We present a case series of SSCD diagnosed in positively identified otosclerosis patients.

METHODS

Retrospective review of clinical case series in two tertiary-referral neurotologic practices was performed. Clinical histories, operative findings, audiograms, and computed tomography (CT) images were reviewed for patients diagnosed with both SSCD and otosclerosis. Patients with present stapedial reflexes were excluded. Comprehensive literature review was performed.

RESULTS

Four cases were identified. Three reported improved hearing with partial or complete closure of the air-bone gap (ABG), including one patient with far-advanced otosclerosis. One patient had no improvement in pure tone average or ABG. One patient reported worsening of preoperative autophony and pulsatile tinnitus, but none developed new postoperative third-window symptoms. CTs demonstrated both SSCD and otosclerosis.

CONCLUSION

Failure to close the ABG in patients with positively identified otosclerosis intraoperatively may be due to SSCD as an occult concomitant diagnosis. SSCD should be considered as a possible cause of persistent conductive hearing loss after stapes surgery.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:1023-1027, 2020.

Histological Study of The Healing of Traumatic Tympanic Membrane Perforation After Vivosorb and Epifilm Application

BACKGROUND

Untreated traumatic tympanic membrane perforations (TMPs) may lead to permanent perforations and hearing loss. There are many materials that have been previously used for repairing the TMPs.

AIMS AND OBJECTIVES

The purpose of this study is to evaluate the clinical and histological effects of Vivosorb (Vv) and Epifilm on healing of TMPs in a rat model.

MATERIAL AND METHODS

The posterior-inferior quadrant of the tympanic membranes (TMs) in right ears of 14 rats was perforated using a 20-g needle and then the animals were randomly divided into 2 equal groups (n = 7). The perforated right TMs were treated with either Vv (Vv group) or Epifilm (Ep group). The left TMs of 7 rats were perforated in same way and allowed to close spontaneously without any topical material applications (spontaneous closure group as sham control, SC). The left tympanic membranes of the other 7 rats were not perforated and used as normal controls (NC group). On postoperative 15th day, tympanic bullas were extracted from killed rats and examined morphometrically and histopathologically.

RESULTS

Perforation closure rate was 85.7% (6/7) in both Vv and SC groups. Perforations of Ep group closed in 7/7 (100%) ears. The thicknesses of the perforated membranes were increased in SC and especially Vv groups. Also, connective tissue fibrosis, blood clots, and epithelial degenerations were detected in SC and Vv groups. The mean fibroblastic reaction scores of Vv, Ep, and SC groups were 2.14(+), 0.57(+), and 1.71(+) respectively, on comparison with NC group. The mean neovascularization score was 1.42(+) in Vv group, 0.14(+) in Ep group, and 0.57(+) in SC group.

CONCLUSION AND SIGNIFICANCE

Vivosorb and especially Epifilm can improve the healing process in traumatic TMPs and additionally, Epifilm might be more preferred for the treatment of TMPs because of causing lesser fibrosis.

Postoperative Venous Thromboembolism after Extracranial Otologic Surgery

OBJECTIVE

To determine the incidence of postoperative venous thromboembolism (VTE) in adults undergoing otologic surgery.

STUDY DESIGN

Cross-sectional retrospective study.

SETTING

Single tertiary academic center.

SUBJECTS AND METHODS

Adults undergoing nononcologic, extracranial otologic surgery from August 2009 to December 2016. Patients with postoperative diagnosis VTE codes were identified. Imaging and clinical documents were searched for VTE evidence within the first 30 postoperative days. Methods of thromboprophylaxis were documented, and Caprini risk scores were calculated.

RESULTS

In total, 1213 otologic surgeries were evaluated. No postoperative VTE events were identified (0/1268). Mean age was 51.0 ± 17.3 years (range, 18.1-93.4 years). Average length of surgery was 136.0 ± 79.0 minutes (range, 5-768 minutes). The average Caprini score in all patients was 4.0 ± 1.7 (range, 1-15). Eighty-five percent of patients had a Caprini score ≥3, the threshold at which chemoprophylaxis has been recommended in general surgery patients by the American College of Chest Physicians 2012 guidelines. Six patients had documented preoperative chemoprophylaxis and a Caprini score of 4.8 ± 1.7. This was not significantly different from that of patients who did not receive preoperative chemoprophylaxis (t test, P = .3). The literature would estimate a rate of 3.7% VTE in adults with similar Caprini scores undergoing general surgery procedures with no VTE prophylaxis.

CONCLUSION

The Caprini risk assessment model may overestimate VTE risk in patients undergoing extracranial otologic surgery. Postoperative VTE following otologic surgery is rare, even in patients traditionally considered moderate or high risk. Chemoprophylaxis guidelines in this group should be balanced against the potential risk of increased intraoperative bleeding and its associated effects on surgical visualization and morbidity.

Thermal Variations of Operative Microscopes in Otology

Objectives (1) Measure temperature variations achieved by common otomicroscopes. (2) Raise awareness about possible thermal injury during otologic procedures with the advent of newer, high-powered otomicroscopes. (3) Describe optical technology that aims to reduce the potential for thermal injury. Methods A variety of otomicroscopes, with different light sources (ranging from 100W halogen to 300W xenon), were studied. Temperatures were recorded from human auricular skin with a noncontact infrared thermometer at various microscope light intensities and with use of irrigation. Multiple recordings were done at 5-minute intervals, and a working distance of 225 mm was maintained. Results Maximum skin temperatures were found to plateau relatively quickly, with higher-wattage xenon light sources reaching greater temperatures. One-way analysis of variance revealed significant differences in temperatures with decreased light intensities. High-wattage xenon light sources reached significantly higher temperatures when compared with halogen models. Discussion There is substantial variation in maximal skin temperatures reached by otomicroscopes. Temperatures can be decreased to safe levels by reducing light intensity and with use of irrigation. The maximum temperature obtained in our study was 41.4°C. Second-degree skin burns have been described with prolonged exposures to temperatures >44°C. Implications for Practice Given the described potential for burns, surgeons performing procedures on the ear and temporal bone should take precautions to diminish temperature in the operative field.

Global surgery in a postconflict setting--5-year results of implementation in the Russian North Caucasus

Background

Collaborations for global surgery face many challenges to achieve fair and safe patient care and to build sustainable capacity. The 2004 terrorist attack on a school in Beslan in North Ossetia in the Russian North Caucasus left many victims with complex otologic barotrauma. In response, we implemented a global surgery partnership between the Vladikavkaz Children's Hospital, international surgical teams, the North Ossetian Health Ministry, and civil society organizations. This study's aim was to describe the implementation and 5-year results of capacity building for complex surgery in a postconflict, mid-income setting.

Design

We conducted an observational study at the Children's Hospital in Vladikavkaz in the autonomous Republic of North Ossetia-Alania, part of the Russian Federation. We assessed the outcomes of 15 initial patients who received otologic surgeries for complex barotrauma resulting from the Beslan terrorism attack and for other indications, and report the incidence of intra- and postoperative complications.

Results

Patients were treated for trauma related to terrorism (53%) and for indications not related to violence (47%). None of the patients developed peri- or postoperative complications. Three patients (two victims of terrorism) who underwent repair of tympanic perforations presented with re-perforations. Four junior and senior surgeons were trained on-site and in Germany to perform and teach similar procedures autonomously.

Conclusions

In mid-income, postconflict settings, complex surgery can be safely implemented and achieve patient outcomes comparable to global standards. Capacity building can build on existing resources, such as operation room management, nursing, and anesthesia services. In postconflict environments, substantial surgical burden is not directly attributable to conflict-related injury and disease, but to health systems weakened by conflicts. Extending training and safe surgical care to include specialized interventions such as microsurgery are integral components to strengthen local capacity and ownership. Our experience identified strategies for fair patient selection and might provide a model for potentially sustainable surgical system building in postconflict environments.

Preliminary Testing of a Compact, Bone-Attached Robot for Otologic Surgery

Otologic surgery often involves a mastoidectomy procedure, in which part of the temporal bone is milled away in order to visualize critical structures embedded in the bone and safely access the middle and inner ear. We propose to automate this portion of the surgery using a compact, bone-attached milling robot. A high level of accuracy is required to avoid damage to vital anatomy along the surgical path, most notably the facial nerve, making this procedure well-suited for robotic intervention. In this study, several of the design considerations are discussed and a robot design and prototype are presented. The prototype is a 4 degrees-of-freedom robot similar to a four-axis milling machine that mounts to the patient's skull. A positioning frame, containing fiducial markers and attachment points for the robot, is rigidly attached to the skull of the patient, and a CT scan is acquired. The target bone volume is manually segmented in the CT by the surgeon and automatically converted to a milling path and robot trajectory. The robot is then attached to the positioning frame and is used to drill the desired volume. The accuracy of the entire system (image processing, planning, robot) was evaluated at several critical locations within or near the target bone volume with a mean free space accuracy result of 0.50 mm or less at all points. A milling test in a phantom material was then performed to evaluate the surgical workflow. The resulting milled volume did not violate any critical structures.

Variability of the temporal bone surface's topography: implications for otologic surgery

Otologic surgery is performed for a variety of reasons including treatment of recurrent ear infections, alleviation of dizziness, and restoration of hearing loss. A typical ear surgery consists of a tympanomastoidectomy in which both the middle ear is explored via a tympanic membrane flap and the bone behind the ear is removed via mastoidectomy to treat disease and/or provide additional access. The mastoid dissection is performed using a high-speed drill to excavate bone based on a pre-operative CT scan. Intraoperatively, the surface of the mastoid component of the temporal bone provides visual feedback allowing the surgeon to guide their dissection. Dissection begins in "safe areas" which, based on surface topography, are believed to be correlated with greatest distance from surface to vital anatomy thus decreasing the chance of injury to the brain, large blood vessels (e.g. the internal jugular vein and internal carotid artery), the inner ear, and the facial nerve. "Safe areas" have been identified based on surgical experience with no identifiable studies showing correlation of the surface with subsurface anatomy. The purpose of our study was to investigate whether such a correlation exists. Through a three-step registration process, we defined a correspondence between each of twenty five clinically-applicable temporal bone CT scans of patients and an atlas and explored displacement and angular differences of surface topography and depth of critical structures from the surface of the skull. The results of this study reflect current knowledge of osteogenesis and anatomy. Based on two features (distance and angular difference), two regions (suprahelical and posterior) of the temporal bone show the least variability between surface and subsurface anatomy.