Anterior Clinoidectomy and Opening of the Internal Auditory Canal Using an Ultrasonic Bone Curette

Neurosurgery ◽  
2003 ◽  
Vol 52 (4) ◽  
pp. 867-871 ◽  
Author(s):  
Hiromu Hadeishi ◽  
Akifumi Suzuki ◽  
Nobuyuki Yasui ◽  
Yuichirou Satou
Keyword(s):  
High Speed ◽  
Longitudinal Vibration ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Ultrasonic Frequency ◽  
Surgical Equipment ◽  
Anterior Clinoidectomy ◽  
Paraclinoid Aneurysm ◽  
Controlled Irrigation ◽  
Cranial Base Surgery

Abstract OBJECTIVE During cranial base surgery, use of a high-speed drill for osteotomy has become common. We performed anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette, and we report the advantages and clinical applications of this method. DESCRIPTION OF INSTRUMENTATION The ultrasonic surgical equipment comprises a power supply unit, footswitch, and handpiece (weight, 110 g; diameter, 20 mm; length, 140 mm from tip to angled section). The handpiece tip is 2 mm wide, and the amplitude of longitudinal vibration can be varied from 120 to 365 μm at an ultrasonic frequency of 25 kHz. Cool-controlled irrigation fluid emerges near the tip, through the sheath. EXPERIENCE AND RESULTS We performed anterior clinoidectomy in eight cases of paraclinoid aneurysm and opening of the internal auditory canal in six cases of acoustic neuroma without damage to the dura mater or nearby structures such as brain tissue, blood vessels, and cranial nerves. In addition, no damage to the facial nerve or labyrinthine organ resulted from heat or vibration caused by the ultrasonic bone curette. CONCLUSION Ultrasonic bone curettage represents safe instrumentation for performance of anterior clinoidectomy and opening of the internal auditory canal without damage to surrounding structures. This technique allows surgeons to perform procedures on deep areas without incurring psychomotor stress.

scholarly journals Trigeminal Nerve Schwannoma of the Cerebellopontine Angle

2018 ◽  
Vol 79 (S 05) ◽  
pp. S389-S390
Author(s):  
Maria Peris-Celda ◽  
Christopher Graffeo ◽  
Avital Perry ◽  
Lucas Carlstrom ◽  
Michael Link
Keyword(s):  
Trigeminal Nerve ◽  
Cerebellopontine Angle ◽  
Incidental Finding ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Clinical History ◽  
Sensory Loss ◽  
Meckel’S Cave ◽  
Neurologic Deficits ◽  
Meckel's Cave

Introduction Large and even moderate sized, extra-axial cerebellopontine angle (CPA) tumors may fill this restricted space and distort the regional anatomy. It may be difficult to determine even with high resolution magnetic resonance imaging (MRI) if the tumor is dural-based, or what the nerve of origin is if a schwannoma. While clinical history and exam are helpful, they are not unequivocal, particularly since many patients present with a myriad of symptoms, or conversely an incidental finding. We present an atypical appearing, asymptomatic CPA tumor, ultimately identified at surgery to be a trigeminal schwannoma. Case History A 40-year-old man presented with new-onset seizure. MRI identified an incidental heterogeneously contrast-enhancing CPA lesion (Fig. 1A–D). The tumor was centered on the internal auditory canal (IAC) with no tumor extension into Meckel's cave, IAC or jugular foramen. Audiometry demonstrated 10db of relative left-sided hearing loss with 100% word recognition. Physical examination was negative for focal neurologic deficits. A retrosigmoid craniotomy was performed and an extra-axial, yellow-hued mass was encountered and resected, which was ultimately confirmed to originate from the trigeminal nerve (Video 1). Gross total resection was achieved, and the patient recovered from surgery with partial ipsilateral trigeminal sensory loss and no other new neurologic deficits. Conclusion Pure CPA trigeminal schwannomas are rare, but should be considered in the differential for enhancing CPA lesions. Although, Meckel's cave involvement is frequently observed, it is not universal, and pure CPA schwannomas of all cranial nerves IV–XII have been reported in the literature.The link to the video can be found at: https://youtu.be/AlodYCu70F8.

High Jugular Bulb: Implications for Posterior Fossa Neurotologic and Cranial Base Surgery

1993 ◽  
Vol 102 (2) ◽  
pp. 100-107 ◽  
Author(s):  
Steven D. Rauch ◽  
Wen-Zhuang Xv ◽  
Joseph B. Nadol
Keyword(s):  
Temporal Bone ◽  
Posterior Fossa ◽  
Cerebellopontine Angle ◽  
Internal Auditory Canal ◽  
Petrous Bone ◽  
Jugular Bulb ◽  
Variable Position ◽  
High Jugular Bulb ◽  
Cranial Base Surgery ◽  
Bone Exposure

The suboccipital-retrosigmoid approach to the internal auditory canal and cerebellopontine angle is being used with increasing frequency for neurotologic surgery, including vestibular nerve section and resection of acoustic neuroma. It offers wide exposure of the cerebellopontine angle and the cranial nerve VII—VIII complex as it courses from the brain stem to the temporal bone. Exposure of the internal auditory canal can be achieved by removing its posterior bony wall. Safe utilization of this approach requires familiarity with the variable position of structures within the petrous bone, including the lateral venous sinus and jugular bulb. We report here a case in which bleeding resulted from injury to a high jugular bulb during surgical exposure of the internal auditory canal via the suboccipital route and discuss the regional anatomy of the jugular bulb based on study of 378 consecutive temporal bone specimens from the collection of the Massachusetts Eye and Ear Infirmary. High jugular bulb was defined as encroachment of the dome of the bulb within 2 mm of the floor of the internal auditory canal. Forty-six percent of scoreable specimens met this criterion. However, when donors less than 6 years of age were excluded, a high jugular bulb was identified in 63% of specimens. Relevance to neurotologic surgery of the posterior fossa is presented.

scholarly journals Central nervous system integration of sensorimotor signals in oral and pharyngeal structures: oropharyngeal kinematics response to recurrent laryngeal nerve lesion

2016 ◽  
Vol 120 (5) ◽  
pp. 495-502 ◽  
Author(s):  
Francois D. H. Gould ◽  
Jocelyn Ohlemacher ◽  
Andrew R. Lammers ◽  
Andrew Gross ◽  
Ashley Ballester ◽  
...  
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
High Speed ◽  
Motor Coordination ◽  
Cranial Nerves ◽  
Laryngeal Nerve ◽  
Nerve Lesion ◽  
Airway Protection ◽  
Liquid Feeding ◽  
Laryngeal Sensation ◽  
Central Coordination

Safe, efficient liquid feeding in infant mammals requires the central coordination of oropharyngeal structures innervated by multiple cranial and spinal nerves. The importance of laryngeal sensation and central sensorimotor integration in this system is poorly understood. Recurrent laryngeal nerve lesion (RLN) results in increased aspiration, though the mechanism for this is unclear. This study aimed to determine the effect of unilateral RLN lesion on the motor coordination of infant liquid feeding. We hypothesized that 1) RLN lesion results in modified swallow kinematics, 2) postlesion oropharyngeal kinematics of unsafe swallows differ from those of safe swallows, and 3) nonswallowing phases of the feeding cycle show changed kinematics postlesion. We implanted radio opaque markers in infant pigs and filmed them pre- and postlesion with high-speed videofluoroscopy. Markers locations were digitized, and swallows were assessed for airway protection. RLN lesion resulted in modified kinematics of the tongue relative to the epiglottis in safe swallows. In lesioned animals, safe swallow kinematics differed from unsafe swallows. Unsafe swallow postlesion kinematics resembled prelesion safe swallows. The movement of the tongue was reduced in oral transport postlesion. Between different regions of the tongue, response to lesion was similar, and relative timing within the tongue was unchanged. RLN lesion has a pervasive effect on infant feeding kinematics, related to the efficiency of airway protection. The timing of tongue and hyolaryngeal kinematics in swallows is a crucial locus for swallow disruption. Laryngeal sensation is essential for the central coordination in feeding of oropharyngeal structures receiving motor inputs from different cranial nerves.

Anatomic Considerations of the Medial Cuts in the Subtotal Temporal Bone Resection

1982 ◽  
Vol 90 (5) ◽  
pp. 641-645 ◽  
Author(s):  
J. Gail Neely ◽  
Michael Forrester
Keyword(s):  
Temporal Bone ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Lateral Wall ◽  
En Bloc Resection ◽  
Bloc Resection ◽  
Bone Resection ◽  
En Bloc ◽  
Temporal Bone Resection ◽  
Temporal Bones

Eighteen temporal bones, 20 sets of polytomograms, and two sets of histologically sectioned temporal bones were studied and the literature was reviewed in order to describe the evolution and anatomic detail of the medial limits of the subtotal temporal bone resection used when malignant neoplasia has invaded the middle ear. An en bloc resection requires incisions medial to the pneumatized spaces involved. The anatomy of the lines of resection through the glenoid fossa, medial to the lateral wall of the carotid canal, through the cochlea, internal auditory canal, and jugular bulb, and just lateral to cranial nerves IX, X, and XI was described in detail. Regardless of the techniques employed, or the feasibility of the task, the concept of en bloc resection must conform to the anatomy of the region.

scholarly journals Internal Auditory Canal Reconstruction After Vestibular Schwannomas Removal Through Retrosigmoid-Transmeatal Approach

2018 ◽  
Vol 26 (3) ◽  
pp. 237-241
Author(s):  
Ricardo Ramina ◽  
Gustavo Simiano Jung ◽  
Erasmo Barros Da Silva Jr ◽  
Guilherme José Agnoletto ◽  
Luis Fernando Moura Da Silva Jr ◽  
...  
Keyword(s):  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Jugular Foramen ◽  
Vestibular Schwannomas ◽  
Fat Tissue ◽  
Resonance Imaging ◽  
Tumor Removal ◽  
Postoperative Mri ◽  
Csf Leakage ◽  
Magnetic Resonance Imaging Mri

Objectives: To present a technique of internal auditory canal (IAC) reconstruction using a pediculated dural flap, after removal of vestibular schwannomas through the retrosigmoid craniotomy. Methods: From a series of 213 patients with vestibular schwannomas operated between January 2008 and March 2016 through the retrosigmoid-transmeatal approach, 183 underwent reconstruction of the internal auditory canal with a pediculated dural flap. The IAC was drilled towards the fundus preserving the labyrinthine structures. The dura mater over the IAC was dissected from the bone, remaining pediculated at the entrance of the jugular foramen. This dural flap was used to cover the cranial nerves inside the IAC after tumor removal. Opened mastoid cells and the IAC were closed with muscle or fat grafts and fibrin glue. Results: Reconstruction of the IAC using the described technique was possible in in 183 cases. Fifteen patients (6.8%) developed postoperative cerebrospinal fluid (CSF) leakage and seven patients required reoperation (3.2%) to close the fistulae. Postoperative magnetic resonance imaging (MRI) examinations showed the presence of CSF within the IAC around the preserved cranial nerves. Conclusions: This technique of IAC reconstruction after surgical resection of vestibular schwannomas may avoid scar and adhesion of muscle or fat tissue with preserved cranial nerves, allowing CSF enter inside the IAC. It may help to identify tumor remnants and/or recurrences in postoperative MRI examinations. Comparative studies are needed to evaluate if this technique improves postoperative hearing and facial nerve outcomes.

scholarly journals Anatomical location of AICA loop in CPA as a prognostic factor for ISSNHL

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6582 ◽  
Author(s):  
Sang Hyub Kim ◽  
Yeo Rim Ju ◽  
Ji Eun Choi ◽  
Jae Yun Jung ◽  
Sang Yoon Kim ◽  
...  
Keyword(s):  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Anterior Inferior Cerebellar Artery ◽  
Anatomical Location ◽  
Hearing Improvement ◽  
Cerebellar Artery ◽  
Hearing Recovery ◽  
Type Classification ◽  
Pure Tone Threshold

The cerebellopontine angle (CPA) is a triangular-shaped space that lies at the junction of the pons and cerebellum. It contains cranial nerves and the anterior inferior cerebellar artery (AICA). The anatomical shape and location of the AICA is variable within the CPA and internal auditory canal (IAC). A possible etiology of idiopathic sudden sensorineural hearing loss (ISSNHL) is ischemia of the labyrinthine artery, which is a branch of the AICA. As such, the position of the AICA within the CPA and IAC may be related to the clinical development of ISSNHL. We adopted two methods to classify the anatomic position of the AICA, then analyzed whether these classifications affected the clinical features and prognosis of ISSNHL. We retrospectively reviewed patient data from January 2015 to March 2018. Two established classification methods designed by Cahvada and Gorrie et al. were used. Pure tone threshold at four different frequencies (0.5, 1, 4, and 8 kHz), at two different time points (at initial presentation and three months after treatment), were analyzed. We compared the affected and unaffected ears, and investigated whether there were any differences in hearing recovery and symptoms between the two classification types. There was no difference in AICA types between ears with and without ISSNHL. Patients who had combined symptoms such as tinnitus and vertigo did not show a different AICA distribution compared with patients who did not. There were differences in quantitative hearing improvement between AICA types, although without statistic significance (p = 0.09–0.13). At two frequencies, 1 and 4 kHz, there were differences in Chavda types between hearing improvement and no improvement (p < 0.05). Anatomical variances of the AICA loop position did not affect the incidence of ISSNHL or co-morbid symptoms including tinnitus and vertigo. In contrast, comparisons of hearing improvement based on Chavda type classification showed a statistical difference, with a higher proportion of Chavda type 1 showing improvements in hearing (AICA outside IAC).

scholarly journals Generation and Evolution Conditions of Polygonal Wear of High-Speed Wheel

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Yahong Dong ◽  
Shuqian Cao
Keyword(s):  
High Speed ◽  
Longitudinal Vibration ◽  
Rotation Frequency ◽  
Element Model ◽  
Eighth Order ◽  
Bending Vibration ◽  
Constant Frequency ◽  
Mass Eccentricity ◽  
Polygonal Wear ◽  
Wheel Track

Wheel polygonal wear has long been a problem that confused the safety of railway operation which has important theoretical value and research significance. In this paper, the conditions of polygonal wear of high-speed wheel are analyzed based on the wear model and verified by the field measured data. Considering the wheel track interaction caused by rotation, a finite element model of wheelset rotor dynamics is established. The effects of rotor speed, mass eccentricity, wheelset, and track flexibility on the vibration characteristics of wheelset rotor system and wheel polygonal wear characteristics are analyzed by beam element and solid element, respectively. The results show that the wheel longitudinal vibration is the main reason of wheel polygonal wear, and the wheel polygonal wear follows the law of “constant frequency and divisible.” Its “constant frequency” comes from the wheel track contact vibration, which stimulates the third-order vertical bending vibration of wheelset and the eighth-order coupled bending vibration of track, and the order is equal to the ratio of “constant frequency” to the wheelset rotation frequency.

scholarly journals Comprehensive Effect of Arc and Ultrasonic Energy on MIG Arc Ultrasonic Welding

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4884
Author(s):  
Qihao Chen ◽  
Chengcheng Wang ◽  
Yihao Wang ◽  
Jiahui Wang ◽  
Sanbao Lin ◽  
...  
Keyword(s):  
Energy Density ◽  
High Speed ◽  
Weld Zone ◽  
Ultrasonic Energy ◽  
Second Phase ◽  
Ultrasonic Frequency ◽  
Excitation Voltage ◽  
Welding Arc ◽  
Arc Shape ◽  
Frequency Current

Ultrasonic energy is introduced into the Metal Inert Gas (MIG) welding arc and weld pool by superposition of an ultrasonic frequency current. In this study, the arc shape, arc energy, and ultrasonic energy that responded to ultrasonic excitation voltage and frequency is investigated. The comprehensive influence of arc and ultrasonic energy on weld formation, microstructure, and mechanical properties is further studied. The arc and ultrasonic energy are analyzed by using a high-speed camera and microphone, respectively. The results showed that the arc width increased, and the arc energy density decreased after the superposition of ultrasonic current. The arc height could be compressed under certain ultrasonic excitation parameters. The ultrasonic excitation voltage and frequency had a direct influence on the ultrasonic energy. The arc height, arc energy density, and ultrasonic energy together determined the weld width. Ultrasound could effectively refine the microstructure of the weld zone and fusion zone but had little effect on the heat-affected zone. Ultrasound improved the hardness of the joint by refining the grain and the second phase. The joint hardness was the highest when the ultrasonic excitation voltage was 100 V, and the frequency was 30 kHz.

Dynamic analysis of high-speed traction elevator and traction car–rope time-varying system

2019 ◽  
Vol 50 (2) ◽  
pp. 37-45 ◽  
Author(s):  
Qing Zhang ◽  
Yu-hu Yang ◽  
Tao Hou ◽  
Rui-jun Zhang
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Longitudinal Vibration ◽  
Variable Mass ◽  
Traction Force ◽  
Vertical Vibration ◽  
Time Varying ◽  
Quintic Polynomial ◽  
Input Motion ◽  
Rope System

In this study, the compensating ropes and tension device on elevator vibration, as well as the car and hoisting ropes between the top of the car and traction wheel in a high-speed traction elevator lift system, were considered a system to analyze the effect of traction force. In addition, the vertical vibration of the system was used as the research object. The influence of hoisting ropes quality was measured, and a time-varying dynamic model with variable mass, damping, and stiffness for the car–hoisting rope system was constructed from the perspective of time-varying structural mechanics. Simultaneously, the ideal running state of the elevator, which is fitted by using the quintic polynomial, was utilized as input motion parameter. Then, a case study was conducted by using the fine integral method for the vertical vibration dynamic model of the car–hoisting rope system. Finally, the nonlinear vertical vibration response of the car–hoisting rope system during the operation of high-speed traction elevator was obtained. Results indicated that the influence of traction force, compensating ropes, and tension device on the vibration of the car–hoisting rope system when the elevator is in the upward process is greater than when the elevator is in the downward process. In addition, the low quality of the elevator car leads to the production of strong longitudinal vibration. The linear density of the hoisting ropes has a slight effect on the longitudinal vibration of elevator.

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