Topographic Changes in Petrous Bone Anatomy in the Presence of a Vestibular Schwannoma and Implications for the Retrosigmoid Transmeatal Approach

2014 ◽  
Vol 10 (3) ◽  
pp. 481-486 ◽  
Author(s):  
Florian H. Ebner ◽  
Maximilian Kleiter ◽  
Sören Danz ◽  
Ulrike Ernemann ◽  
Bernhard Hirt ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Petrous Bone ◽  
Sigmoid Sinus ◽  
Medial Border ◽  
Vestibular Aqueduct ◽  
Hearing Function ◽  
Before And After ◽  
Risk Pattern

AbstractBACKGROUND:The maneuver of transmeatal drilling carries the risk of injuring inner ear structures, which may cause immediate or delayed hearing loss.OBJECTIVE:To describe the changes in petrous bone anatomy caused by the tumor and to analyze both the incidence and the risk pattern for violation of the endolymphatic system in a surgical series.METHODS:One hundred patients operated on for vestibular schwannoma were included in this prospective study. Thin-slice computed tomography was performed before and after surgery. We assessed topographic measurements on both the pathological and healthy sides. Postoperatively, we evaluated anatomic and functional values.RESULTS:The diameter of the internal auditory canal was significantly larger (P < .001) in the petrous bones of the affected sides than in the contralateral healthy sides. An average of 5.6 ± 1.8 mm of the internal auditory canal was drilled, and the distance from the medial border of the sigmoid sinus to the drilling line (tangential to the drilled surface of the posterior lip of the internal auditory canal) was 9.8 ± 2.9 mm. A postoperative violation of the vestibular aqueduct (VA) was detected in 41 cases; the VA was intact in 55 cases; and the VA could not be clearly defined in 4 cases. The incidence of VA injury increased with increasing tumor size. In the patient group with good preoperative and postoperative hearing function, a VA injury occurred in 26% of cases, whereas the incidence increased to 67% in preoperatively deaf patients.CONCLUSION:Vestibular schwannomas cause significant distortion of the petrous bone anatomy. Detailed preoperative knowledge of the topography is necessary for the preservation of function.

Modified translabyrinthine approach and hearing preservation: imaging evaluation

2007 ◽  
Vol 121 (8) ◽  
pp. 736-741 ◽  
Author(s):  
G Magliulo ◽  
A Stasolla ◽  
D Parrotto ◽  
M Marini
Keyword(s):  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Hearing Preservation ◽  
Ct Scans ◽  
Successful Outcome ◽  
Imaging Evaluation ◽  
Translabyrinthine Approach ◽  
Hearing Function ◽  
Mri Scans ◽  
Magnetic Resonance Imaging Mri

AbstractAim:To establish if the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of the vestibule, after the removal of vestibular schwannoma by a modified translabyrinthine approach, correlate with a successful outcome, defined as hearing preservation.Materials and methods:Our study group consisted of 16 patients with vestibular schwannoma. All patients' pre-operative hearing was graded as class one or two according to the Gardner–Robertson scale. On MRI scans, the schwannoma, including the intracanalicular segment, were less than 2 cm in size in all the patients. The intracanalicular portion involved the fundus of the internal auditory canal in seven patients. In the remaining nine patients, the schwannoma had spread to involve two-thirds of the meatus, sparing its lateral third. The state of the labyrinth, in particular the integrity of the vestibule, was evaluated by CT scans and MRI prior to and following surgery.Results:The schwannoma was completely removed in all patients. None showed any signs of persistence or tumoral relapse on the post-operative MRI. The final follow up showed that seven patients had maintained their hearing function (i.e. four patients with class one hearing and three with class two). The MRI vestibular signal on the T2-weighted images was well depicted only in patients with hearing preservation. Bony vestibular integrity was observed in the CT scans of all cases with hearing preservation, and also in three cases with failure of hearing preservation.Conclusion:Our results confirm that total isolation and maintenance of an anatomically intact vestibule, as depicted by MRI examination, is one of the fundamental factors for successful preservation of hearing function following modified translabyrinthine approach schwannoma removal.

scholarly journals An aberrant venous channel mimicking the perilabyrinthine cells in the petrous bone of a patient with vestibular schwannoma: illustrative case

2021 ◽  
Vol 2 (18) ◽  
Author(s):  
Masato Ito ◽  
Yoshinori Higuchi ◽  
Kentaro Horiguchi ◽  
Shigeki Nakano ◽  
Shinichi Origuchi ◽  
...  
Keyword(s):  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Posterior Wall ◽  
Anatomical Variations ◽  
Petrous Bone ◽  
Bone Defects ◽  
Jugular Bulb ◽  
Illustrative Case ◽  
Computed Tomographic ◽  
Major Vein

BACKGROUND Anatomical variations, such as high jugular bulbs and air cell development in the petrosal bone, should be evaluated before surgery. Most bone defects in the internal auditory canal (IAC) posterior wall are observed in the perilabyrinthine cells. An aberrant vascular structure passing through the petrous bone is rare. OBSERVATIONS A 48-year-old man presented with a right ear hearing disturbance. Magnetic resonance imaging revealed a 23-mm contrast-enhancing mass in the right cerebellopontine angle extending into the IAC, consistent with a right vestibular schwannoma. Preoperative bone window computed tomographic scans showed bone defects in the IAC posterior wall, which ran farther posteroinferiorly in the petrous bone, reaching the medial part of the jugular bulb. The tumor was accessed via a lateral suboccipital approach. There was no other major vein in the cerebellomedullary cistern, except for the vein running from the brain stem to the IAC posterior wall. To avoid complications due to venous congestion, the authors did not drill out the IAC posterior wall or remove the tumor in the IAC. LESSONS Several aberrant veins in the petrous bone are primitive head sinus remnants. Although rare, their surgical implication is critical in patients with vestibular schwannomas.

Enlarged vestibular aqueducts and other inner-ear abnormalities in patients with Down syndrome

2016 ◽  
Vol 131 (4) ◽  
pp. 298-302 ◽  
Author(s):  
C M Clark ◽  
H H Patel ◽  
S G Kanekar ◽  
H Isildak
Keyword(s):  
Computed Tomography ◽  
Hearing Loss ◽  
Down Syndrome ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Internal Auditory Canal ◽  
Sensorineural Hearing ◽  
Vestibular Aqueduct ◽  
Computed Tomography Images ◽  
Temporal Bones

AbstractBackground:Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.Methods:A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.Results:Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.Conclusion:Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

Recovery of low-frequency sensorineural hearing loss following resection of a greater superficial petrosal nerve schwannoma

2007 ◽  
Vol 107 (1) ◽  
pp. 181-184 ◽  
Author(s):  
Burak Sade ◽  
Joung H. Lee
Keyword(s):  
Hearing Loss ◽  
Facial Nerve ◽  
Internal Auditory Canal ◽  
Low Frequency ◽  
Petrous Bone ◽  
Significant Loss ◽  
Speech Discrimination ◽  
Hearing Function ◽  
Greater Superficial Petrosal Nerve ◽  
Grade Ii

✓Facial nerve schwannomas can occur anywhere from the internal auditory canal to the parotid gland. Schwannomas arising from the greater superficial petrosal nerve are exceedingly rare. The authors report the case of a 63-year-old woman who presented with a selective low-frequency hearing loss of 3 weeks' duration. Neurological examination demonstrated a House–Brackmann Grade II facial paresis and asymmetrical hearing loss on the left side. Audiometric evaluation showed a significant loss of low-frequency hearing with a speech reception threshold (SRT) of 30 dB and a speech discrimination score (SDS) of 88% on the left side. Magnetic resonance imaging revealed a 2.4-cm enhancing left middle fossa mass. Near-complete resection was performed via a left temporal craniotomy. The tumor was located in the Glasscock triangle and had invaded the petrous bone overlying the cochlea. A very small piece of the tumor over the cochlea was left in order to preserve hearing. A postoperative audiogram showed significant improvement in the patient's hearing, with an SRT of 20 dB and an SDS of 100%. The histological findings were consistent with schwannoma. The patient experienced postoperative improvement of hearing function despite cochlear involvement, which has previously been reported as an unfavorable factor for postoperative hearing outcome in facial nerve schwannomas.

Transapical extension in difficult cerebellopontine angle tumours: preliminary report

2003 ◽  
Vol 117 (10) ◽  
pp. 788-792 ◽  
Author(s):  
Mario Sanna ◽  
Manoj Agarwal ◽  
Yogesh Jain ◽  
Alessandra Russo ◽  
Abdel Kader Taibah
Keyword(s):  
Vestibular Schwannoma ◽  
Cerebellopontine Angle ◽  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Petrous Bone ◽  
Vestibular Schwannomas ◽  
Type I ◽  
Posterior Surface ◽  
Prepontine Cistern ◽  
Anterior Extension

Difficult cerebellopontine angle (CPA) tumours namely large/giant vestibular schwannomas, vestibular schwannomas with a significant anterior extension and meningiomas of the posterior surface of the petrous bone extending anterior to the internal auditory canal (IAC) have always posed a problem for the otoneurosurgeon. Modifications of the enlarged translabyrinthine approach (ETLA) specifically aimed at dealing with these tumours are not reported. The aim of this paper is to introduce the transapical extension of ETLA which involves increased circumferential drilling around the IAC beyond 270°C. The extension allows enhanced surgical control over the tumour as well as the anterior aspect of the CPA including the prepontine cistern, the Vth and VIth cranial nerves. The extension is further classified into Type I and II depending upon the extent of drilling. Type I extension entails drilling around the IAC for 300–320° and is indicated for large/giant vestibular schwannomas (large vestibular schwannoma extrameatal diameter 3–3.9 cm, giant vestibular schwannoma extrameatal diameter [ges ]4 cm) and vestibular schwannomas with significant anterior extension. Type II extension involves complete drilling around the canal for 360° and is indicated for meningiomas of the posterior surface of the petrous bone extending anterior to the IAC.

Petrous Bone Pneumatization Is a Risk Factor for Cerebrospinal Fluid Fistula Following Vestibular Schwannoma Surgery

2010 ◽  
Vol 67 (suppl_2) ◽  
pp. ons509-ons515 ◽  
Author(s):  
Lennart Henning Stieglitz ◽  
Mario Giordano ◽  
Venelin Gerganov ◽  
Andreas Raabe ◽  
Amir Samii ◽  
...  
Keyword(s):  
Risk Factor ◽  
Cell Volume ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Tumor Grade ◽  
Petrous Bone ◽  
Control Group ◽  
Surgical Removal ◽  
Csf Fistula ◽  
The Mean

ABSTRACT BACKGROUND: For the prevention of postoperative CSF fistula a better understanding of origins and risk factors is necessary. OBJECTIVE: To identify the petrous bone air cell volume as a risk factor for developing CSF fistula, we performed a retrospective analysis. METHODS: From 2000 to 2007 519 patients had a retrosigmoidal surgical removal of a vestibular schwannoma. The 22 who had a postoperative CSF fistula were chosen for evaluation in addition to 78 patients who were randomly selected in 4 equally sized cohorts: male/female with small/large tumors. Preoperative CT scans were analyzed regarding petrous bone air cell volume, area of visible pneumatization at the level of the internal auditory canal (IAC), tumor grade, and sex. RESULTS: Women developed nearly half as many CSF fistulas (2.7%) as men (5.2%). The mean volume of the petrous bone air cells was 10.97 mL (SD, 4.9; range, 1.38-27.25). It was significantly lower for women (mean, 9.23 mL; SD, 3.8) than for men (mean, 12.5 mL; SD, 5.28; P = .0008). The mean air cell volume of CSF-fistula patients was 13.72 mL (SD, 5.22). The difference concerning the air cell volume between patients who developed CSF fistulas and patients from the control group was significant (P = .0042). There was a significant positive correlation between the air cell volume and the area of pneumatization in one CT slide at the level of the IAC. CONCLUSION: The higher incidence of CSF fistulas in men compared with women can be explained by means of differently pneumatized petrous bones. A high amount of petrous bone pneumatization has to be considered as a risk factor for the development of postoperative CSF fistula after vestibular schwannoma surgery.

Cerebrospinal fluid (CSF) otorhinorrhoea following vestibular schwannoma surgery treated by extended subtotal petrosectomy with obliteration

1993 ◽  
Vol 107 (12) ◽  
pp. 1122-1124 ◽  
Author(s):  
Jona Kronenberg ◽  
Erez Bendet ◽  
Gideon Findler ◽  
Yehudah Roth
Keyword(s):  
Cerebrospinal Fluid ◽  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Semicircular Canals ◽  
Jugular Bulb ◽  
Sigmoid Sinus ◽  
Mastoid Cell ◽  
Csf Leakage ◽  
Subtotal Petrosectomy

Extended subtotal petrosectomy as a treatment for persistent cerebrospinal fluid (CSF) otorhinorrhoea is presented. Four patients were successfully operated on by this technique, all previously having undergone suboccipital removal of vestibular schwannoma: other interventions used had failed to seal the fistulae. The internal auditory canal was the usual pathway for CSF leakage as well as retrosigmoid, retrolabyrinthine, retro- or perifacial cells. Total exenteration of middle ear and mastoid cell tracts, skeletonization of sigmoid sinus, jugular bulb and facial nerve, drilling out of semicircular canals, vestibule, and cochlea, and skeletonization of the internal auditory canal, followed by obliteration, are the main steps of this approach.

Mid-aortic syndrome: computed tomography angiography depicting extensive collateral circulation in an 11-year-old patient with thoracoabdominal aortic coarctation

VASA ◽  
2012 ◽  
Vol 41 (2) ◽  
pp. 132-135 ◽  
Author(s):  
Krohn ◽  
Gebauer ◽  
Hübler ◽  
Beck
Keyword(s):  
Computed Tomography ◽  
Computed Tomography Angiography ◽  
Collateral Circulation ◽  
Intestinal Ischemia ◽  
Clinical Presentation ◽  
Lower Limbs ◽  
Upper Body ◽  
Descending Aorta ◽  
Before And After ◽  
Blood Pressures

The mid-aortic syndrome is an uncommon clinical condition characterized by severe narrowing of the descending aorta, usually with involvement of its renal and visceral branches, presenting with uncontrollably elevated blood pressures of the upper body, renal and cardiac failure, intestinal ischemia, encephalopathy symptoms and claudication of the lower limbs, although clinical presentation is variable. In this article we report the case of an eleven-year-old patient with the initial diagnosis of a mid-aortic syndrome and present the computed tomography angiography pictures and reconstructions before and after surgical therapy.

Spreading of the vestibular schwannoma into porus acusticus internus. Endoscopic removal possibilities

2018 ◽  
pp. 40-44
Author(s):  
Orest Palamar ◽  
Andriy Huk ◽  
Dmytro Okonskyi ◽  
Ruslan Aksyonov ◽  
Dmytro Teslenko
Keyword(s):  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Residual Tumor ◽  
Endoscopic Technique ◽  
Vestibular Schwannomas ◽  
Endoscopic Removal ◽  
Tumor Removal ◽  
Tumor Spread ◽  
Microsurgical Technique ◽  
Tumor Visualization

Aim: To investigate the features of the vestibular schwannoma spread into the internal auditory canal and the possibilities of endoscopic removal. Objectives: To improve tumor visualization in the internal auditory canal; to create a sufficient view angle for tumor removal during endoscopic opening of the internal auditory canal. Materials and methods: The results of surgical treatment of 20 patients with vestibular schwannomas in which the tumor spread to the internal auditory canal were analyzed. Microsurgical tumor removal was performed in 14 cases; Fully endoscopic removal of vestibular schwannomas was performed in 6 cases. The internal auditory canal opening was performed in 14 cases using microsurgical technique and in 6 cases with fully the endoscopic technique. Results: Gross total removal was achieved in 18 cases, subtotal removal in 2 cases. The tumor spread into the internal auditory canal was removed in all cases (100%). Opening the internal auditory canal using the endoscopic technique allows to increase the view angle (up to 20%) and to visualize along the axis of canal. Conclusions: 1) Endoscopic assistance technique allows to improve residual tumor visualization much more better then microsurgical technique; 2) Internal auditory canal opening using endoscopic technique is much more effective than the microsurgical technique (trepanning depth is larger); 3) Endoscopic methods for the internal auditory canal opening allows to increase canal angle view up to 20% (comparing to the microsurgical view).

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