Extradural dermoid tumor of the petrous apex. Case report

Dermoid cysts are rare, benign, congenital tumors. Most case series thus far have featured intradural tumors. The authors report on a case of an extradural dermoid tumor of the middle cranial fossa with osseous invasion, successfully removed using a left subtemporal extradural approach. The clinical presentation, histological features, radiological findings, and management of this unique case are described.     

Extradural neuromas at the petrous apex: report of two cases

OBJECTIVE AND IMPORTANCE: Two rare cases of middle cranial fossa neuroma located in the epidural space at the petrous apex are reported. CLINICAL PRESENTATION: Two women, aged 58 and 49 years, were admitted to our hospital with diagnoses of cavernous sinus tumor. Analysis of preoperative computed tomography scans showed bone erosion of the petrous apex, and magnetic resonance imaging demonstrated the presence of an extradural mass located along the course of the petrous internal carotid artery in both patients. INTERVENTION: The tumor was completely removed in one patient and partially removed in the other by use of the epidural middle cranial fossa transpetrosal approach. In both patients, histological examination of tumor specimens revealed neuroma. CONCLUSION: Because surgical exploration revealed that these epidural tumors adhered tightly to the internal carotid artery, and because they had no relationship to the trigeminal nerve, facial nerve, or proximal greater superficial petrosal nerve, in our opinion, these tumors originated from the distal portion of the greater superficial petrosal nerve or the deep petrosal nerve. These neuromas were mainly found in a site under the cavernous sinus at the petrous apex, a location not previously reported.     

Extradural approach for cavernous hemangioma of the cavernous sinus: experience with 13 cases

The clinical, radiological, and surgical issues concerning cavernous hemangiomas located within the dural confines of the cavernous sinus were analyzed on the basis of experience with 13 cases. The feasibility of radical resection by an entirely extradural approach using a basal temporal surgical route to this relatively rare and formidable surgical problem was investigated. Thirteen patients, four males and nine females, with cavernous hemangioma involving the cavernous sinus were treated from 1992 to 2001. The patients were aged from 15 to 55 years. Headaches and deficits of the cranial nerves coursing through the cavernous sinus were the principal symptoms at presentation. Vision was affected in four patients. The radiological features in all patients were similar with a characteristic pattern of extension and encasement of internal carotid artery. The maximum size of the tumor was 28 to 73 mm (mean 44 mm). An entirely extradural route using the basal temporal approach was used successfully in seven cases. Total resection was achieved in 12 patients and partial resection was achieved in one patient. The follow up ranged from 8 months to 9 years (mean 45 months). The outcome of extraocular movements was poor in our series, possibly due to the massive sizes of the tumors encountered. There was no recurrence or growth of the residual tumor and all patients were leading active lives.     

Cholesterol granuloma of the petrous apex and sphenoidal sinus: a case report

A case of a cholesterol granuloma located in the petrous apex and eroding into the sphenoidal sinus is reported. Cholesterol granuloma is thought to occur when pneumatized cells in the temporal bone become obstructed. Although usually occurring in the middle ear, it can occur in the petrous apex. The diagnosis and surgical management are discussed.     

Two-staged gamma knife radiosurgery for the treatment of large petroclival and cavernous sinus meningiomas.

BACKGROUND: In this study, we report on the effectiveness and usefulness of two-staged gamma knife radiosurgery (GKS) for large petroclival and cavernous sinus meningiomas that have a high rate of surgical morbidity. METHODS: We have treated 7 patients suffering from large petroclival and cavernous sinus meningiomas using two-staged radiosurgery since March 1995. The tumors were located in the petroclival region in 4 patients, the cavernous sinus region in 2 patients, and in the petrocavernous region in the remaining patient. Three of the patients had been surgically treated and 4 patients (57%) were only followed with MR imaging. The volume of the tumors ranged between 34.5 to 101 cm(3) (mean 53.5 cm(3)). The treatment volume was between 6.8 to 29.6 cm(3) (mean 18.6 cm(3)). The treatment interval between the first GKS and second GKS was 6 months. The marginal doses for the tumors were 8 to 12 Gy (mean, 9 Gy). RESULTS: Six patients demonstrated tumor growth control during the follow-up period after the first radiosurgery (mean 39 months). Tumor regression was observed in 3 patients (43%). Three patients (43%) had improved clinically by the time of the follow-up examinations. No patient suffered from symptomatic radiation injury. CONCLUSION: Although we have treated only 7 patients using two-staged GKS, we believe this treatment may be a very useful option for large petroclival and cavernous sinus meningiomas in selected patients.     

Partial labyrinthectomy petrous apicectomy approach to the petroclival region: an anatomic and technical study

OBJECTIVE: The petroclival region generally is thought to be an inaccessible area in the intracranial compartment. A number of ways of reaching this area during surgery have been described, including the presigmoid petrosal approach. The partial labyrinthectomy petrous apicectomy approach is a relatively new approach to this region and is a variant of the presigmoid petrosal approach. This study aims to demonstrate the technique and the microsurgical anatomy of the partial labyrinthectomy petrous apicectomy approach and to provide a quantitative study of its exposure to compare it with other common approaches to this region, particularly the presigmoid petrosal approach. METHODS: Bilateral stepwise dissections were performed on 15 formalin-fixed and dye-injected cadaveric heads (30 sides) under x3 to x40 magnification. A temporal craniotomy was performed after a complete mastoidectomy. A partial labyrinthectomy and petrous apicectomy were performed next. The amount of dura exposed was measured before and after the partial labyrinthectomy and the petrous apicectomy. By measuring the angles of exposure, the approach was examined to analyze how much increased access was gained. RESULTS: This approach provided wide exposure to the petroclival region, the cerebellopontine angle, Meckel's cave, the cavernous sinus, and the prepontine region. On average, there was an increase of 10.8 mm in horizontal exposure as compared with the retrolabyrinthine approach. The average angle of vision achieved with the clival pit as the target was 58.9 degrees. In most of the specimens, an area from the IIIrd to the IXth cranial nerves was easily visible without any significant brain retraction. A high jugular bulb did not reduce the exposure. CONCLUSION: The partial labyrinthectomy petrous apicectomy approach converts two narrow tunnels into a wide corridor. It increases the angle of exposure markedly, providing easy and excellent exposure of the otherwise difficult-to-access petroclival region, and it may also preserve hearing.     

Infralabyrinthine approach for cholesterol granuloma of the petrous apex

Cholesterol granuloma of the petrous apex are cystic lesions, revealed by otologic and/or cranial nerve palsies, and diagnosed with the help of computed tomography and magnetic resonance imaging. Surgical treatment is not the complete removal of the lesion, but a conservative approach requiring drainage of the cyst and re-establishment of a correct aeration of the cavity. Three cases of cholesterol granuloma of the petrous apex were treated through a transmastoid infralabyrinthine procedure. Through a postauricular approach, a simple mastoidectomy was performed. The third portion of the facial nerve was identified. The posterior and lateral semicircular canals, and the jugular bulb were skeletonized. In two cases, a high diverticulum of the jugular bulb was impacted downwards with wax. The cystic lesion was then opened, and evacuated. The opening must be large to permit a correct aeration of the cavity and prevent stenosis of the drainage site. Hearing and the facial function were preserved in all cases. In conclusion, conservative approach to cholesterol granuloma of the petrous apex provides satisfactory drainage of this intrapetrous deep seated lesion with preservation of hearing and facial nerve function.     

Removal of petrous apex meningioma and microvascular decompression for trigeminal neuralgia through the anterior petrosal approach. Case report.

A 64-year-old female presented with right trigeminal neuralgia. Computed tomography and magnetic resonance (MR) imaging demonstrated a tumor attached to the right petrous apex. MR imaging also revealed that the trigeminal nerve was compressed and distorted by the tumor. Tumor removal and microvascular decompression (MVD) were performed via the anterior petrosal approach. The trigeminal nerve was distorted by the tumor and the superior cerebellar artery compressed the medial part of the root entry zone of the trigeminal nerve. The surgery resulted in complete relief of the trigeminal neuralgia. Posterior fossa tumors causing ipsilateral trigeminal neuralgia are not rare, and are often removed via the suboccipital retromastoid approach, as MVD for trigeminal neuralgia is usually performed through the retromastoid approach. The advantages of the anterior petrosal approach are shorter access to the lesion and direct exposure without interference from the cranial nerves, and that bleeding from the tumors is easily controlled as the feeding arteries can be managed in the early stage of the surgery. We conclude that the anterior petrosal approach is safe and advantageous for the removal of petrous apex tumor associated with trigeminal neuralgia.     

A giant thrombosed aneurysm of the petrous carotid artery presenting with cavernous sinus syndrome: case report

Aneurysms involving the petrous Carotid artery are rare and a review of the literature demonstrates that the mode of clinical presentation depends on the direction of expansion of the aneurysmal sac. The eighth nerve is the most commonly affected, followed by the fifth nerve, sixth nerve and seventh nerve, respectively. There has not been reported to date a lesion presenting with cavernous sinus syndrome. We present the case of a 46-year-old woman who complained of left facial pain and pan-ophthalmoplegia, and was shown to have a giant thrombosed aneurysm of the petrous carotid artery extending into the cavernous sinus. Because preoperative evaluation of the patient revealed good collateral flow, proximal balloon occlusion of the left internal carotid artery was performed. Neurological symptoms of the patient resolved 2 months after surgery except for the size of the left pupil. We conclude that an aneurysm of the petrous carotid artery should be included in the differential diagnosis of cases presenting with a cavernous sinus syndrome. Early diagnosis followed by definitive treatment is important for the alleviation of clinical symptoms associated with this lesion.     

Detailed anatomy knowledge: first step to approach petroclival meningiomas through the petrous apex. Anatomy lab experience and surgical series

Petroclival meningiomas are a challenge for neurosurgeons due to the complex anatomy of the region that is rich of vessels and nerves. A perfect and detailed knowledge of the anatomy is very demanding in neurosurgery, especially in skull base surgery. The authors describe the microsurgical anatomy to perform an anterior petrosectomy based on their anatomical and surgical experience and perform a literature review. The temporal bone is the most complex and fascinating bone of skull base. The apex is located in the angle between the greater wing of the sphenoid and the occipital bone. Removing the petrous apex exposes the clivus. The approach directed through the temporal bone in this anatomical area is referred to as an anterior petrosectomy. The area that must be drilled is the rhomboid fossa that is defined by the Kawase, premeatal, and postmeatal triangles. In Division of Neurosurgery - University of Turin, 130 patients, from August 2013 to September 2015, underwent surgical resection of intracranial meningiomas. In this group, we have operated 7 PCMs and 5 of these were approached performing an anterior petrosectomy with good results. In our conclusions, we feel that this surgery require an advanced knowledge of human anatomy and a specialized training in interpretation of radiological and microsurgical anatomy both in the dissection lab and in the operating room.     

Subcochlear approach for cholesterol granulomas of the inferior petrous apex

Cholesterol granulomas of the petrous apex are drained through two major extralabyrinthine routes: one, along the posterosuperior chain of air cells, and two, along the anteroinferior chain. Procedures that use the posterosuperior chain approach the apex from the sinodural angle, the base of the zygomatic arch, the attic, or through the arch of the superior semicircular canal. Operations that use the anteroinferior chain reach the apex along the internal carotid canal (Ramadier's operation) or by a posterior infralabyrinthine approach between the descending facial nerve and jugular bulb. Inferior petrous apex cholesterol granulomas may be unreachable by any of these routes, and hence the subcochlear route is proposed as an alternative. The subcochlear approach starts in a triangle bounded superiorly by the cochlea, anteriorly by the internal carotid canal and posteriorly by the deep jugular vein. This operation requires lowering the inferior bony canal wall to the level of the "crutch." It provides access to an inferiorly situated cholesterol granuloma, yet preserves hearing. It allows enough room for the placement of a tube drain from the petrous apex to the mastoid. It is particularly useful when a high jugular bulb precludes the use of the posterior infralabyrinthine route.     

Epidermoid and cholesterol cysts in the apex of the petrous bone

Cystic lesions in the petrous apex are nearly always either epidermoid cysts, with a soft but solid content, or cholesterol cysts, containing brown fluid. They may be symptomless, produce progressive cranial nerve palsies or, occasionally, reach the CSF pathways thus leading either to meningitis or a CSF leak. Thirteen cases and four unverified cases have been encountered amongst a series of more than 500 cerebellopontine angle tumours. Their clinical features, radiological diagnosis and difficulties of surgical approach are discussed.