Surgery of the ear and the lateral skull base: pitfalls and complications

Healthcare consumption among subjects with otitis media undergoing middle ear surgery-analysis of cost drivers

PURPOSE

To map healthcare utilized by subjects with chronic otitis media, with or without cholesteatoma and perform a cost analysis to determine key drivers of healthcare expenditure.

METHODS

A registry study of 656 adult subjects with chronic otitis media that underwent a middle ear surgery between 2014 and 2018. Healthcare contacts related to all publicly funded specialist ENT care, audiological care and primary care for a disease of the ear and mastoid process were extracted. The data are extracted from the Swedish National Patient Registry on subjects that reside in western Sweden.

RESULTS

Subjects made 13,782 healthcare contacts at a total cost 61.1 million SEK (6.0 million EUR) between 2014 and 2018. The mean cost per subject was 93,075 SEK (9071 EUR) and ranged between 3971 SEK (387 EUR) and 468,711 SEK (45,683 EUR) per individual. In the most expensive quartile of subjects, mean cost was 192,353 SEK (18,747 EUR) over the 5-year period. These subjects made 3227 ENT contacts (roughly four each year) and 60% of total costs were associated with in-patient ENT care.

CONCLUSION

Patients with chronic otitis media are associated with high ENT resource utilization that does not diminish after surgical intervention and the disease places a long-term burden on healthcare systems. Significant costs are attributed to revision surgeries, indicating that these patients could be managed more effectively. In many such cases, reoperation cannot be avoided, especially due to recurrence of cholesteatoma. However, in some patients, when the indication for subsequent surgery is only hearing improvement, alternative options, such as hearing aids or implants, should also be considered. This is especially true in difficult cases, where revision ossiculoplasty is likely.

Penetration of the Vestibule Following a History of Stapedectomy

This case study describes a 72-year-old female with a history of stapedectomy 40 years prior. She presented experiencing vertigo, fogginess, and imbalance for 9 months. Computed tomography (CT) imaging revealed that the prosthesis was displaced into the vestibule by approximately 2.1 to 2.4 mm. The patient was presented with treatment options, including observation, removal, replacement of the prosthesis, and an oval window patch. The patient opted for observation as the symptoms she was experiencing did not significantly impact her quality of life. Although a stapedectomy may fail for a multitude of reasons, some of the most common causes are prosthesis displacement, especially out of the oval window into the middle ear or away from the incus. Incus necrosis may also play a substantial role in failure.

Automated Registration-Based Temporal Bone Computed Tomography Segmentation for Applications in Neurotologic Surgery

OBJECTIVE

This study investigates the accuracy of an automated method to rapidly segment relevant temporal bone anatomy from cone beam computed tomography (CT) images. Implementation of this segmentation pipeline has potential to improve surgical safety and decrease operative time by augmenting preoperative planning and interfacing with image-guided robotic surgical systems.

STUDY DESIGN

Descriptive study of predicted segmentations.

SETTING

Academic institution.

METHODS

We have developed a computational pipeline based on the symmetric normalization registration method that predicts segmentations of anatomic structures in temporal bone CT scans using a labeled atlas. To evaluate accuracy, we created a data set by manually labeling relevant anatomic structures (eg, ossicles, labyrinth, facial nerve, external auditory canal, dura) for 16 deidentified high-resolution cone beam temporal bone CT images. Automated segmentations from this pipeline were compared against ground-truth manual segmentations by using modified Hausdorff distances and Dice scores. Runtimes were documented to determine the computational requirements of this method.

RESULTS

Modified Hausdorff distances and Dice scores between predicted and ground-truth labels were as follows: malleus (0.100 ± 0.054 mm; Dice, 0.827 ± 0.068), incus (0.100 ± 0.033 mm; Dice, 0.837 ± 0.068), stapes (0.157 ± 0.048 mm; Dice, 0.358 ± 0.100), labyrinth (0.169 ± 0.100 mm; Dice, 0.838 ± 0.060), and facial nerve (0.522 ± 0.278 mm; Dice, 0.567 ± 0.130). A quad-core 16GB RAM workstation completed this segmentation pipeline in 10 minutes.

CONCLUSIONS

We demonstrated submillimeter accuracy for automated segmentation of temporal bone anatomy when compared against hand-segmented ground truth using our template registration pipeline. This method is not dependent on the training data volume that plagues many complex deep learning models. Favorable runtime and low computational requirements underscore this method's translational potential.

Automated objective surgical planning for lateral skull base tumors

PURPOSE

Surgical removal of pathology at the lateral skull base is challenging because of the proximity of critical anatomical structures which can lead to significant morbidity when damaged or traversed. Pre-operative computed surgical approach planning has the potential to aid in selection of the optimal approach to remove pathology and minimize complications.

METHODS

We propose an automated surgical approach planning algorithm to derive the optimal approach to vestibular schwannomas in the internal auditory canal for hearing preservation surgery. The algorithm selects between the middle cranial fossa and retrosigmoid approach by utilizing a unique segmentation of each patient's anatomy and a cost function to minimize potential surgical morbidity.

RESULTS

Patients who underwent hearing preservation surgery for vestibular schwannoma resection (n = 9) were included in the cohort. Middle cranial fossa surgery was performed in 5 patients, and retrosigmoid surgery was performed in 4. The algorithm favored the performed surgical approach in 6 of 9 patients.

CONCLUSION

We developed a method for computing morbidity costs of surgical paths to objectively analyze surgical approaches at the lateral skull base. Computed pre-operative planning may assist in surgical decision making, trainee education, and improving clinical outcomes.

Facial Nerve Monitoring under Different Levels of Neuromuscular Blockade with Cisatracurium Besilate in Parotid Tumour Surgery

Background

Anaesthesia can alter neuronal excitability and vascular reactivity and ultimately lead to neurovascular coupling. Precise control of the skeletal muscle relaxant doses is the key in reducing anaesthetic damage.

Methods

A total of 102 patients with the normal functioning preoperative facial nerve who required parotid tumour resection were included in this study. Facial nerve monitoring was conducted intraoperatively. The surgeon stimulated the facial nerve at different myorelaxation intervals at TOF% (T4/T1) and T1% (T1/T0) and recorded the responses and the amplitude of electromyogram (EMG). Body movements (BM) or patient-ventilator asynchrony (PVA) was recorded intraoperatively.

Results

In parotid tumour resection, T1% should be maintained at a range of 30 to 60% while TOF% should be maintained at a range of 20 to 30%. Analysis of the decision tree model for facial nerve monitoring suggests a partial muscle relaxation level of 30% < T1% ≤ 50% and TOF ≤ 60%. A nomogram prediction model, while incorporating factors such as sex, age, BMI, TOF%, and T1%, was constructed to predict the risk of BM/PVA during surgery, showing good predictive performance.

Conclusions

This study revealed an adequate level of neuromuscular blockade in intraoperative parotid tumour resection while conducting facial nerve monitoring. A visual nomogram prediction model was constructed to guide anaesthetists in improving the anaesthetic plan.

Vestibular Schwannoma: What We Know and Where We are Heading

Vestibular schwannoma (VS) is a Schwann cell-derived tumour arising from the vestibulocochlear nerve. Although benign, it represents a threat to intracranial structures due to mass effect and carries a small risk of malignant transformation. VS therefore represents an important healthcare burden. We review the literature regarding pathogenesis, risk factors, and diagnosis of VS. The current and future potential management strategies are also discussed. A narrative review of all relevant papers known to the authors was conducted. The majority of VS remain clinically stable and do not require interventional procedures. Nevertheless, various surgical techniques exist for removing VS, the most common of which are translabyrinthine and retrosigmoid approaches. Due to surgical risks such as hearing loss, facial nerve dysfunction, post-operative headache, and cerebrospinal fluid leakage, a "watch and rescan" approach is adopted for most patients. Radiotherapy is a useful alternative and has been shown to have a similar response for growth restriction. Due to the heterogeneous nature of VS, there is a lack of consensus regarding management of tumours that are too large for conservative management but too small to indicate surgery. Emerging biologic therapies, such as Bevacizumab, Everolimus, and Lapatinib, as well as anti-inflammatories like aspirin are promising potential treatments; however, long-term evidence of their efficacy is required. The knowledge base regarding VS continues to improve. With increased understanding of the pathogenesis of these tumors, we believe future work should focus on pharmacologic intervention. Biologic therapies aimed toward improved patient outcomes are particularly promising.

Facial Nerve Intraoperative Monitoring in Otologic Surgeries under Sedation and Local Anesthesia - A Case Series and Literature Review

Introduction  Local anesthesia with sedation has been employed for an increasingly number of otolaryngology procedures, and might be associated with lower surgical morbidity and costs. Facial nerve monitoring is often advisable in otology to minimize the risks of injuries to this cranial nerve, but the principles, techniques and parameters involved have only been studied for procedures under general anesthesia. Objective  To report the preliminary outcomes of intraoperative facial nerve monitoring during otologic procedures under sedation and local anesthesia. Methods  A total of five procedures and their respective intraoperative electrophysiological main findings were described. Facial neuromonitoring was performed using the same device by an electrophysiologist. The monitor sensitivity was set at 100 mV, and a stimulating probe was used whenever needed. Results  Progressively decreasing low-amplitude baseline values were usually obtained as the level of anesthesia increased, with isolated oscillations possibly related to some degree of voluntary muscular activity. These oscillations could be easily distinguished from those of the surgical manipulation or electrical stimulation of the nerve, which tended to be of much greater amplitude and shorter latency, occurring during specific surgical steps. Conclusion  With a surgical team with proper procedural knowledge and broad expertise regarding the technique, intraoperative facial nerve monitoring under local anesthesia with sedation seemed both feasible and reliable. Thus, the need for intraoperative neuromonitoring should not be an obstacle for otologic procedures under less aggressive anesthetic management.

Incidence of Prolonged Systemic Steroid Treatment after Surgery for Acoustic Neuroma and Its Implications

Objectives  To determine the incidence of prolonged postoperative systemic corticosteroid therapy after surgery for acoustic neuroma as well as the indications and associated risk factors that could lead to prolonged steroid administration, and the incidence of steroid-related adverse effects. Study Designs  Retrospective chart review. Methods  Retrospective chart review of patients undergoing resection of acoustic neuroma between 2010 and 2017 at two tertiary care medical centers. Patient and tumor characteristics, operative approach, hospital length of stay, initial postoperative taper length, number of discrete postoperative steroid courses, and postoperative complications were analyzed. Results  There were 220 patients (99 male, 121 female) with an average age of 49.4 (range 16-78). There were 124 left-sided tumors and 96 right-sided tumors. Within the group, 191 tumors were operated through a retrosigmoid approach, 25 tumors through a translabyrinthine approach, and 4 tumors with a combined retrosigmoid-translabyrinthine approach under the same anesthetic. In total, 35 (15.9%) patients received an extended initial course of postoperative systemic steroids, defined as a taper longer than 18 days. Twenty six (11.8%) patients received additional courses of systemic steroids after the initial postoperative taper. There were 5 (2.3%) patients who required an extended initial taper as well as additional courses of steroids. Aseptic meningitis, often manifested as headache, was the most common indication for additional steroids (14 cases of prolonged taper and 17 cases of additional courses). None of the patient or tumor factors including age, gender, side, size, and approach were statistically significantly associated with either a prolonged initial steroid taper or additional courses of steroids. An extended hospital length of stay was associated with a prolonged initial steroid taper ( p  = 0.03), though the initial taper length was not predictive of additional courses of steroids. The cumulative number of days on steroids was associated with need for additional procedures ( p  < 0.01) as well as steroid-related side effects ( p  = 0.05). The administration of steroids was not found to significantly improve outcomes in postoperative facial paresis. Steroid-related complications were uncommon, seen in 9.26% of patients receiving steroids, with the most common being psychiatric side effects such as agitation, anxiety, and mood lability. Conclusions Systemic corticosteroids are routinely administered postoperatively for patients undergoing craniotomy for the resection of acoustic neuromas. In a review of 220 patients operated by a single neurotologist, no patient or tumor factors were predictive of requiring prolonged initial steroid taper or additional courses of steroids. The cumulative number of days on systemic steroids was associated with undergoing additional procedures and steroid-related side effects. The most common indications for prolonged or additional steroids were aseptic meningitis, cerebrospinal fluid leak, and facial paresis. Additional steroids for postoperative facial paresis did not significantly improve outcomes. Patient-reported steroid-related complications were infrequent and were most commonly psychiatric including agitation, anxiety, and mood lability.

A giant cholesteatoma of the mastoid extending into the foramen magnum: A case report and review of literature

Cholesteatomas are very rare benign, progressive lesions that have embryologic derivation and usually result in progressive exfoliation and confinement of squamous epithelium behind an intact or preciously infected tympanic membrane. To the best of our understanding no reports demonstrates the extension of cholesteatoma from the temporal bone into the foramen magnum. We therefore present a case of cholesteatoma extending down into the foramen magnum. We report a case of 67- year-old man with a giant cholesteatoma extending into the foramen magnum without substantial destruction of the mastoid and petrous temporal bones. The patient’s major symptoms were recurrent tinnitus in the left ear and dizziness with unilateral conductive hearing loss. A working diagnosis of cholesteatomas was made combining the symptoms and magnetic resonance imaging findings. He was then successfully operated on with very minimal postoperative complications. Cholesteatomas originating from the mastoid bone often linger with the patients for many years in a subclinical state and progress into a massive size before causing symptoms. Patients with unilateral conductive hearing loss who are otherwise asymptomatic and have a normal tympanic membrane should be suspected with a progressive cholesteatoma. Cholesteatoma should be one of the working diagnosis when an elderly patient present with unilateral conductive hearing loss that is associated with tinnitus and dizziness.

Drill-induced Cochlear Injury During Otologic Surgery: Intracochlear Pressure Evidence of Acoustic Trauma

HYPOTHESIS

Drilling on the incus produces intracochlear pressure changes comparable to pressures created by high-intensity acoustic stimuli.

BACKGROUND

New-onset sensorineural hearing loss (SNHL) following mastoid surgery can occur secondary to inadvertent drilling on the ossicular chain. To investigate this, we test the hypothesis that high sound pressure levels are generated when a high-speed drill contacts the incus.

METHODS

Human cadaveric heads underwent mastoidectomy, and fiber-optic sensors were placed in scala tympani and vestibuli to measure intracochlear pressures (PIC). Stapes velocities (Vstap) were measured using single-axis laser Doppler vibrometry. PIC and Vstap were measured while drilling on the incus. Four-millimeter diamond and cutting burrs were used at drill speeds of 20k, 50k, and 80k Hz.

RESULTS

No differences in peak equivalent ear canal noise exposures (134-165 dB SPL) were seen between drill speeds or burr types. Root-mean-square PIC amplitude calculated in third-octave bandwidths around 0.5, 1, 2, 4, and 8 kHz revealed equivalent ear canal (EAC) pressures up to 110 to 112 dB SPL. A statistically significant trend toward increasing noise exposure with decreasing drill speed was seen. No significant differences were noted between burr types. Calculations of equivalent EAC pressure from Vstap were significantly higher at 101 to 116 dB SPL.

CONCLUSION

Our results suggest that incidental drilling on the ossicular chain can generate PIC comparable to high-intensity acoustic stimulation. Drill speed, but not burr type, significantly affected the magnitude of PIC. Inadvertent drilling on the ossicular chain produces intense cochlear stimulation that could cause SNHL.

Temporal Lobe Cystic Collection and Associated Oedema: A Rare Complication of Translabyrinthine Resection of Vestibular Schwannoma

Vestibular schwannomas (VS) are benign tumours arising from the vestibulocochlear nerve. Among the management options available, surgical resection is often considered, especially if lesions are enlarging or symptomatic. Translabyrinthine (TL) resection of a vestibular schwannoma is one of three basic approaches available to the surgeon. Complications generally associated with this approach can include cerebrospinal fluid (CSF) leak, hearing and balance issues, infection, and facial nerve palsies. We present the case of a patient with a previously unreported type of complication: that of cystic CSF collection within the temporal lobe and associated oedema.