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.

Systematic Review of Temporal Bone-Resurfacing Techniques for Pulsatile Tinnitus Associated with Vascular Wall Anomalies

OBJECTIVE

To systematically review literature evidence on temporal bone-resurfacing techniques for pulsatile tinnitus (PT) associated with vascular wall anomalies.

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Database. The period covered was from 1962 to 2018.

REVIEW METHODS

We included studies in all languages that reported resurfacing outcomes for patients with PT and radiographic evidence or direct visualization of sigmoid sinus wall anomaly, jugular bulb wall anomaly, or dehiscent or aberrant internal carotid artery.

RESULTS

Of 954 citations retrieved in database searches and 5 citations retrieved from reference lists, 20 studies with a total of 141 resurfacing cases involving 138 patients were included. Resurfacing outcomes for arterial sources of PT showed 3 of 5 cases (60%) with complete resolution and 2 (40%) with partial resolution. Jugular bulb sources of PT showed 11 of 14 cases (79%) with complete resolution and 1 (7%) with partial resolution. Sigmoid sinus sources of PT showed 91 of 121 cases (75%) with complete resolution and 12 (10%) with partial resolution. Symptoms occurred more in females and on the right side. Most cases (94%) used hard-density materials for resurfacing. Material density did not appear to be associated with resurfacing outcomes. Use of autologous materials was associated with improved outcomes for arterial sources resurfacing. Major complications involving sigmoid sinus thrombosis or compression were reported in 4% of cases without long-term morbidity or mortality.

CONCLUSIONS

Resurfacing surgery is likely effective and well tolerated for select patients with PT associated with various vascular wall anomalies.

Facial Nerve Outcome and Tumor Control Rate as a Function of Degree of Resection in Treatment of Large Acoustic Neuromas: Preliminary Report of the Acoustic Neuroma Subtotal Resection Study (ANSRS)

BACKGROUND

Patients with large vestibular schwannomas are at high risk of poor facial nerve (cranial nerve VII [CNVII]) function after surgery. Subtotal resection potentially offers better outcome, but may lead to higher tumor regrowth.

OBJECTIVE

To assess long-term CNVII function and tumor regrowth in patients with large vestibular schwannomas.

METHODS

Prospective multicenter nonrandomized cohort study of patients with vestibular schwannoma ≥2.5 cm who received gross total resection, near total resection, or subtotal resection. Patients received radiation if tumor remnant showed signs of regrowth.

RESULTS

Seventy-three patients had adequate follow-up with mean tumor diameter of 3.33 cm. Twelve received gross total resection, 22 near total resection, and 39 subtotal resection. Fourteen (21%) remnant tumors continued to grow, of which 11 received radiation, 1 had repeat surgery, and 2 no treatment. Four of the postradiation remnants (36%) required surgical salvage. Tumor regrowth was related to non-cystic nature, larger residual tumor, and subtotal resection. Regrowth was 3 times as likely with subtotal resection compared to gross total resection and near total resection. Good CNVII function was achieved in 67% immediately and 81% at 1-year. Better immediate nerve function was associated with smaller preoperative tumor size and percentage of tumor left behind on magnetic resonance image. Degree of resection defined by surgeon and preoperative tumor size showed weak trend toward better late CNVII function.

CONCLUSION

Likelihood of tumor regrowth was 3 times higher in subtotal resection compared to gross total resection and near total resection groups. Rate of radiation control of growing remnants was suboptimal. Better immediate but not late CNVII outcome was associated with smaller tumors and larger tumor remnants.

ABBREVIATIONS

CNVII, cranial nerve VIIGTR, gross total resectionHB, House-BrackmannMRI, magnetic resonance imageNTR, near total resectionSTR, subtotal resection.

Anatomy-Specific Virtual Reality Simulation in Temporal Bone Dissection: Perceived Utility and Impact on Surgeon Confidence

Objective

To evaluate the effect of anatomy-specific virtual reality (VR) surgical rehearsal on surgeon confidence and temporal bone dissection performance.

Study Design

Prospective pre- and poststudy of a novel virtual surgical rehearsal platform.

Setting

Academic otolaryngology–head and neck surgery residency training programs.

Subjects and Methods

Sixteen otolaryngology–head and neck surgery residents from 2 North American training institutions were recruited. Surveys were administered to assess subjects' baseline confidence in performing 12 subtasks of cortical mastoidectomy with facial recess. A cadaver temporal bone was randomly assigned to each subject. Cadaver specimens were scanned with a clinical computed tomography protocol, allowing the creation of anatomy-specific models for use in a VR surgical rehearsal platform. Subjects then rehearsed a virtual mastoidectomy on data sets derived from their specimens. Surgical confidence surveys were administered again. Subjects then dissected assigned cadaver specimens, which were blindly graded with a modified Welling scale. A final survey assessed the perceived utility of rehearsal on dissection performance.

Results

Of 16 subjects, 14 (87.5%) reported a significant increase in overall confidence after conducting an anatomy-specific VR rehearsal. A significant correlation existed between perceived utility of rehearsal and confidence improvement. The effect of rehearsal on confidence was dependent on trainee experience and the inherent difficulty of the surgical subtask. Postrehearsal confidence correlated strongly with graded dissection performance. Subjects rated anatomy-specific rehearsal as having a moderate to high contribution to their dissection performance.

Conclusion

Anatomy-specific virtual rehearsal improves surgeon confidence in performing mastoid dissection, dependent on surgeon experience and task difficulty. The subjective confidence gained through rehearsal correlates positively with subsequent objective dissection performance.

A new theory on the pathogenesis of acquired cholesteatoma: Mucosal traction

OBJECTIVES/HYPOTHESIS

Although the migration of its squamous outer surface of the tympanic membrane has been well characterized, there is a paucity of data available concerning the migratory behavior of its medial mucosal surface. Existing theories of primary acquired cholesteatoma pathogenesis do not adequately explain the observed characteristics of the disease. We propose a new hypothesis, based upon a conjecture that mucosal membrane interactions are the driving force in cholesteatoma.

STUDY DESIGN

A retrospective chart review and a prospective observational cohort study in rats.

METHODS

After developing the new theory, it was tested through both clinical and experimental observations. To evaluate whether impairment of middle ear mucociliary migration would influence cholesteatoma formation, a retrospective chart review evaluating cholesteatoma occurrence in a sizable population of patients with either primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) was performed. To study mucosal migration on the medial aspect of the tympanic membrane, ink tattoos were monitored over time in a rat model.

RESULTS

No cholesteatomas were identified in either PCD patients (470) or in CF patients (1,910). In the rat model, mucosa of the posterior pars tensa migrated toward the posterior superior quadrant, whereas the mucosa of the anterior pars tensa migrated radially toward the annulus.

CONCLUSION

Mucosal coupling with traction generated by interaction of migrating opposing surfaces provides the first comprehensive theory that explains the observed characteristics of primary acquired cholesteatoma. The somewhat counterintuitive hypothesis that cholesteatoma is fundamentally a mucosal disease has numerous therapeutic implications.

Development and characterization of chemical cochleostomy in the Guinea pig

OBJECTIVES

Creation of an atraumatic, hearing-preservation cochleostomy is integral to the future of minimally invasive inner ear surgery. The goal of this study was to develop and characterize a novel chemical approach to cochleostomy.

STUDY DESIGN

Prospective animal study.

SETTING

Laboratory.

METHODS

Experimental animal study in which phosphoric acid gel (PAG) was used to decalcify the otic capsule in 25 Hartley guinea pigs. Five animals in each of 5 surgical groups were studied: (1) mechanically opening the auditory bulla alone, (2) PAG thinning of the basal turn otic capsule, leaving endosteum covered by a layer of bone, (3) micro-pick manual cochleostomy, (4) PAG chemical cochleostomy, exposing the endosteum, and (5) combined PAG/micro-pick cochleostomy, with initial chemical thinning and subsequent manual removal of the last osseous layer. Preoperative and postoperative auditory brainstem responses and otoacoustic emissions were obtained at 2, 6, 10, and 16 kHz. Hematoxylin and eosin-stained paraffin sections were compared.

RESULTS

Surgical and histologic findings confirmed that application of PAG provided reproducible local bone removal, and cochlear access was enabled. Statistically significant auditory threshold shifts were observed at 10 kHz (P = .048) and 16 kHz (P = .0013) following cochleostomy using PAG alone (group 4) and at 16 kHz using manual cochleostomy (group 3) (P = .028). No statistically significant, postoperative auditory threshold shifts were observed in the other groups, including PAG thinning with manual completion cochleostomy (group 5).

CONCLUSION

Hearing preservation cochleostomy can be performed in an animal model using a novel technique of thinning cochlear bone with PAG and manually completing cochleostomy.

Temporal Bone Radiology: Beyond the Basics

Program Description:

Through this interactive presentation, the audience is exposed to challenging temporal bone radiology cases and offered strategies to improve their interpretation. We will cover key findings for chronic ear disease and conductive hearing loss, lateral skull base lesions, and the petrous apex. The emphasis is placed on subtle but pertinent findings on computed tomography and magnetic resonance imaging examinations and their importance in creating and narrowing a differential diagnoses. We will present guidelines to aid in the efficient acquisition and interpretation of imaging for patients with common otologic symptoms such as vertigo, sudden hearing loss, and pulsatile tinnitus.

Educational Objectives:

(1) Interpret key radiographic findings for common pathologic conditions of the temporal bone. (2) Order appropriate radiographic tests to evaluate common conditions and understand the strengths and limitations of various imaging modalities.

Development and Characterization of Chemical Cochleostomy in the Guinea Pig

Objectives:

Creation of an atraumatic, hearing-preservation cochleostomy is integral to the future of minimally invasive inner ear surgery. Current techniques generally take 1 of 2 approaches: mechanical or thermal. The goal of this study was to develop and characterize a novel chemical approach to cochleostomy.

Methods:

Experimental animal study in which phosphoric acid gel (PAG) was used to decalcify the otic capsule in 25 Hartley guinea pigs. Five animals in each of 5 groups were studied: (1) mechanically opening the auditory bulla alone, (2) PAG thinning of the basal turn otic capsule, leaving endosteum covered by a layer of bone, (3) micro-pick manual cochleostomy, (4) PAG chemical cochleostomy, exposing the endosteum, and (5) combined PAG/micro-pick cochleostomy, with initial chemical thinning and subsequent manual removal of the last osseous layer. Preoperative and postoperative auditory brainstem responses and otoacoustic emissions were obtained at 2, 6, 10, and 16 kHz. Hematoxylin and eosin stained paraffin sections were compared.

Results:

Surgical and histologic findings confirmed that application of PAG provided reproducible local bone removal, and cochlear access was enabled. Statistically significant auditory threshold shifts were observed at 10 and 16 kHz following cochleostomy using PAG alone (group 4), and at 16 kHz using manual cochleostomy (group 3) ( P < .05). No statistically significant postoperative auditory threshold shifts were observed in the other groups, including PAG thinning with manual completion cochleostomy (group 5).

Conclusions:

Hearing preservation cochleostomy can be performed in an animal model using a novel technique of thinning cochlear bone with PAG and manually completing cochleostomy.

Managing the Unexpected in Otologic Surgery

Program Description:

Sponsored by the American Neurotology Society, this interactive presentation aims to provide general practitioners tips and techniques employed by experts in management of intraoperative complications encountered during common otology cases such as tympanoplasty, tympanomastoidectomy, and stapedotomy. The panelists will present illustrative cases and discuss best practice approaches to intraoperative cerebrospinal fluid (CSF) leak and encephaloceles, facial nerve injury, vascular complications, stapedotomy challenges, ossicular chain and external auditory canal damage, and inner ear violation.

Educational Objectives:

(1) Recognize unexpected circumstances and anatomic variations that could lead to complications in otologic surgery. (2) Manage intraoperative complications such as facial nerve palsy, vascular injury, encephaloceles, CSF leaks, postoperative sensorineural hearing loss, and vertigo.

A case of stereotactic radiation in skull base solitary fibrous tumor: more harm than good?

Objective Due to its location, total resection of a skull base solitary fibrous tumor (SFT) can lead to morbidity with injury to lower cranial nerves, and a decision must be made between subtotal resection with possible stereotactic radiotherapy or total resection with cranial nerve morbidity. We report the long-term outcomes and review the literature of a case of stereotactic radiation in SFT to provide evidence for making this decision. Design A retrospective case review. Setting An academic tertiary referral center. Results We present a case with > 10 years follow-up of radiation following skull base SFT, initially misdiagnosed as schwannoma, where radiotherapy did not improve recurrence or metastatic behavior and led to complications during subsequent surgical resection. Conclusions SFT often masquerades as schwannoma, especially in the skull base. Careful immunohistochemistry, including CD34 expression, is critical to the diagnosis and management. This case highlights that total tumor resection of SFT remains the gold standard of treatment. Stereotactic radiation is not recommended in the management of skull base SFT.

Temporal Bone Radiology: Beyond the Basics

Program Description:

Through this interactive presentation, the audience is exposed to challenging temporal bone radiology cases and offered strategies to improve his or her interpretation. We will cover key findings for chronic ear disease and conductive hearing loss, lateral skull base lesions, and the petrous apex. The emphasis is placed on subtle but pertinent findings on computed tomography (CT) and MRI examinations and their importance in creating and narrowing a differential diagnosis. We will present guidelines to aid in the efficient acquisition and interpretation of imaging for patients with common otologic symptoms such as vertigo, sudden hearing loss, and pulsatile tinnitus.

Educational Objectives:

1) Interpret key radiographic findings for common pathologic conditions of the temporal bone. 2) Order appropriate radiographic tests to evaluate common conditions and understand the strengths and limitations of various imaging modalities.

The effect of haptic degrees of freedom on task performance in virtual surgical environments

Force and touch feedback, or haptics, can play a significant role in the realism of virtual reality surgical simulation. While it is accepted that simulators providing haptic feedback often outperform those that do not, little is known about the degree of haptic fidelity required to achieve simulation objectives. This article evaluates the effect that employing haptic rendering with different degrees of freedom (DOF) has on task performance in a virtual environment. Results show that 6-DOF haptic rendering significantly improves task performance over 3-DOF haptic rendering, even if computed torques are not displayed to the user. No significant difference could be observed between under-actuated (force only) and fully-actuated 6-DOF feedback in two surgically-motivated tasks.

Is It Valid to Calculate the 3-Kilohertz Threshold by Averaging 2 and 4 Kilohertz?

Many guidelines for reporting hearing results use the threshold at 3 kilohertz (kHz), a frequency not measured routinely. This study assessed the validity of estimating the missing 3-kHz threshold by averaging the measured thresholds at 2 and 4 kHz. The estimated threshold was compared to the measured threshold at 3 kHz individually and when used in the pure-tone average (PTA) of 0.5, 1, 2, and 3 kHz in audiometric data from 2170 patients. The difference between the estimated and measured thresholds for 3 kHz was within ±5 dB in 72% of audiograms, ±10 dB in 91%, and within ±20 dB in 99% (correlation coefficient r = 0.965). The difference between the PTA threshold using the estimated threshold compared with using the measured threshold at 3 kHz was within ±5 dB in 99% of audiograms ( r = 0.997). The estimated threshold accurately approximates the measured threshold at 3 kHz, especially when incorporated into the PTA.

Correlation of Measured vs Averaged 3kHz Pure Tone Averages

Objective: AAO-HNS reporting guidelines for hearing results recommend a pure tone average (PTA) using thresholds at 0.5, 1, 2, and 3 kHz. 3 kHz measurements, however, are not always included in routine audiometry. We determined the magnitude of PTA errors using 3 kHz thresholds interpolated from 2 and 4 kHz measurements.

Method: Retrospective analysis of audiogram data from an academic, tertiary referral center from April to August 2010. All patients (N = 1,204) in our clinic having audiograms for any reason were eligible for inclusion. Audiograms missing threshold data at any of the frequencies evaluated were excluded.

Results: The difference between calculated and measured 3 kHz was within 5 dB, 10dB, and 20dB in 89.5%, 68.9%, and 98.6% of audiograms respectively. When the 3kHz level varied more than 10 dB from actual, the error underestimated the degree of hearing loss by a 3:1 margin (7.9% vs 2.6%). The steeper the slope of the hearing loss, the greater the divergence of the interpolated value from actual. When factored into the PTA, however, measured verses interpolated thresholds at 3 kHz showed a difference within 5 dB in 98.6%, R = 0.996, with a mean difference of 0.6 dB (SD = 1.7dB).

Conclusion: While interpolation of 3 kHz introduces a degree of error in measurement of this specific frequency, the effect on PTA is minor. These data suggest that 3 kHz thresholds can be reliably interpolated using available 2 and 4 kHz thresholds when utilized in PTAs.