Osteoplastic Transpetrosal Approach

The main two problems in the standard transpetrosal approach are a cosmetic deformity and the cerebrospinal fluid (CSF) leakage. However, until now a few technical innovations has been introduced to overcome these problems. Domestically, there is no reports concerning this technique. We introduce a simple and easy technique of cosmetic reconstruction with a split-thickness mastoid bone flap after transpetrosal approach in three tumorous conditions at cerebellopontine region. This simple technique provides a superior cosmetic result, a significant reduction in uncomfortable symptoms, and a possibility of the CSF leakage.

A Study on the Selection Criteria of Surgical Approaches to Vestibular Schwannomas

This study was carried out in order to clarify the selection criteria of the surgical approaches and validate their efficacy in patients with vestibular schwannoma. The evolution and modification of the transpetrosal approach was evolved into combined approaches to vestibular schwannomas. These approaches have been advocated to reduce the mortality and morbidity as well as to improve the surgical results especially in large acoustic neurinoma. Having been stimulated with the fascinating preliminary surgical results of the suboccipital and combined transpetrosal approaches, we have builded up a decision making policy based on the tumor size and the preoperative hearing status for the surgical approaches to vestibular schwannomas. Between May 1996 and September 1997, 21 patients with vestibular schwannoma including one case of NF II underwent either suboccipital or various transpetrosal approaches. There was no surgical mortality. Gross total removal was achieved in 20 patients(95%). Facial nerve function was preserved in 19(90%) and hearing function in 6(46%) among the 13 patients who underwent hearing preservation surgery. The authors confirmed the validity of various transpetrosal approaches in this study and conclude that our policy on the surgical approaches to vestibular schwannomas is quite reasonable.

Modified Transpertrosal(mini-petrosal) Approach to Petroclival Tumors: Technical Note

The management of petroclival tumors has been improved by the techniques of cranial base surgery. However, these tumors are still among the most difficult cranial base lesions to treat. The t ranspetrosal approach is a routine procedure for petroclival tumors, but there are some disadvantages such as the time-consuming craniotomy during surgery. CSF leakage due to incomplete dural closure, postoperative infection, epidural hematoma and depressed deformity of the mastoid area after surgery. To solve these disadvantages, we modified the transpetrosal approach to mini-pet rosal technique involving total petrosectomy without temporal or suboccipital craniotomy. 11 petroclival tumors were operated on using this technique between August 1994 and August 1997. Gross total removal was achieved in tumors of up to 4cm diameter by this technique. The advantages of this approach are smaller skin incision, shorter operation time, and less postoperative complications such as epidural hematoma, CSF leakage infection, and headache. This technique can be indicated for medium to large petroclival tumors which do not extend to cavernous sinus and Jugular foramen.

Surgical Removal of Large Petroclival Meningiomas: the Transpetrosal Approach

For surgery involving complex lesions of the petroclival region, the transpetrosal approach-which may be anterior or posterioris known to have distinct advantages over traditional approaches. Six patients with large petroclival meningiomas(over 4.5cm), underwent surgery. In three cases, where the lesion extended only into the posterior fossa, the posterior transpetrosal approach was used, and in the other three, where it extended into the Meckels cave or cavernous sinus, surgery involved a combined anterior-posterior transpetrosal approach. In three cases with serviceable hearing, the retrolabyrinthine technique was employed, the remaining three, without serviceable hearing, were subjected to the translabyrinthine technique. Total removal was achieved in three cases(50%), and no patient died. Immediate postoperative neurological dysfunction appeared in all cases; almost all involved new cranial nerve deficit. As time passed, this dysfunction became less serious, though in four cases, it was permanent; there was mild to moderate hemiparesis in two cases and facial nerve paralysis in two. The surgical outcome was good in four cases, fair in one and poor in one. The authors suggest that the selection of surgical approach to petroclival meningiomas should be based upon the size and location of the tumor, the extent of dural attachment and the status of the patient's hearing. For a high-risk group, with brain stem invasion, arterial and cranial nerve encasement and cavernous sinus invasion, subtotal resection of the tumor is recommended.

Surgical Experiences of Transpetrosal Approach in Petroclival Lesions

This is a report of 15 consecutive cases of petroclival lesions performed by transpetrosal approach over five years. Pathologies from these cases include 13 cases of tumors and two cases of aneurysms. All cases of tumors were over 4.5cm in size. Two cases of very low-lying basilar bifurcation aneurysms and one case of facial schwanoma extended to the petrosal tip and temporal fossa were operated with anrerior transpetrosal approach, where as nine cases of petroclival tumor which was localized in the posterior fossa were operated via posterior transpetrosal approach. Of these nine cases, one case with lower clival extension was removed totally by adding a retrosigmoid dural opening. Remaining three cases extended to the Meckel's cave or cavernous sinus were operated by combined anterior-posterior transpetrosal approach. Of the 12 cases done with posterior transpetrosal or combined approach, nine cases with preserved serviceable hearing were approached by retrolabylinthine technique and remaining three cases without preservation of serviceable hearing were operated via retrolabylinthine technique. Total removal was achieved in 9 of 13 tumor cases. Of two cases, aneurysmal neck of the first case was clipped completely but was clipped together with right posterior cerebral artery in second case. There was no operative mortality. Immediate postoperative neurological dysfunction were appered in 12 cases. These were significantly improved by the time of follow up examination. Permanent postoperative dysfunction was present in 6 cases, hemiparesis in 2, facial paralysis in 2 and hearing impairment in 2 cases. These results suggest that when selecting the surgical approach to the petroclival lesions, the size, location, extent of the lesion and preoperative status of the hearing were important factors to be considered. We recommend combined anterior-posterior transpetrosal approach for the complex lesions in the petroclival area which extends into the middle fossa(Meckel's cavum or cavernous sinus). Also, we recommend combining with retrosigmoid dural opening or a far lateral type of suboccipital exposure in cases of complex petroclival lesions involving the entire clivus or foramen magnum. In cases with brain stem invasion by tumor, vascular encasement or cavernous sinus invasion without cranial nerve involvement, we recommend subtotal resection of the tumor and radiosurgery to prevent permanent postoperative sequele.

Partial Posterior Canal Labyrinthectomy for Pontine Cavernous Angioma

The transpetrosal approach to the anterior portion of a brain stem lesion with intact hearing is often limited by portions of the labyrinth. The technique of partial labyrinthectomy, by which the posterior and superior semicircular canals, maximizes surgical exposure while preserving hearing. We report the case of a patient who underwent a modified partial labyrinthectomy involving resection of the posterior semicircular canal only in the area of the labyrinth. Technical modification of the partial labyrinthectomy approach simplifies tumor removal while preserving hearing.

A Case of Huge Clival Meningioma: Case Report

Meningiomas in the clival region are not common. These tumors present some of the most formidable challenges in skull base surgery. Total removal of clival meningoma has carried a significant mortality and morbidity. Several approches and combinations of approaches have been used remove clival meningiomas. Transpetrosal operations have been shown to offer distinct advantages over traditional operations in approaching lesions of the clival area. The authors report a case of a huge clival meningioma that was totally removed using posterior transpetrosal translabyrinthine approach.

Transpetrosal Approach with Partial Labyrinthectomy for Hearing Preservation: Technical Note and Case Report

The transpetrosal transtentorial supra- and infratentorial combined approach has been used by many skull base surgeons for the total removal of large tumors in the cerebellopontine, petroclival, and dumbbell-shaped mass of the middle and posterior cranial bases. When surgeons use the retrolabyrinthine approach for hearing preservation, adequate exposure of the presigmoid dura might be hard to achive. In order to get a wider operating field with hearing preservation, the authors used the transpetrosal approach with partial labyrinthectomy for a large dermoid cyst in the cerebellopontine angle which extened to the middle cranial base through the Meckel's cave.

Subtemporal Transpetrosal Approach for Aneurysms of the Low-Lying Basilar Bifurcation

Surgical approaches for aneurysms of the basilar artery trunk are variable and utilized depending on the location of the aneurysms and direction of the fundus of the aneurysms. We operated one patient with low lying basilar bifurcation aneurysms facing toward the brain stem by subtemporal transpetrosal approach with successful clipping of aneurysms. The advantage of this approach to low-lying basilar bifurcation or basilar trunk aneurysms over the pterional, subtemporal(transtentorial), combined supratentorial and infratentorial, transoral, and suboccipital approach are discussed.