Anterior transpetrosal and subtemporal transtentorial approaches for pontine cavernomas

Objective  

Pontine cavernomas are benign vascular lesions whose surgical treatment is challenging due to their localization. We report our experience in the surgical management of these lesions exclusively using a lateral, subtemporal transtentorial approach in high pontine lesions and an anterior petrosal approach in low pontine lesions.     

Four subtypes of petroclival meningiomas: differences in symptoms and operative findings using the anterior transpetrosal approach

Summary   Background. Petroclival meningiomas are vaguely defined as tumours arising from the antero-medial zone to the internal auditory meatus. This report subclassifies petroclival meningiomas based on their origin determined by using radiological and intra-operative findings. Method. Ninety-one patients with petroclival meningioma underwent surgery via the anterior transpetrosal approach. The Meckel’s cave was routinely opened. Tumour origin was classified into four subtypes according to the main attachment and trigeminal nerve deviation into, upper clivus (UC), cavernous sinus (CS), tentorium (TE), and petrous apex (PA). Their characteristic clinical symptoms and anatomical features were investigated. Findings. The characteristic symptom was ataxia in the UC type (37.5%), abducens nerve palsy in the CS type (64.3%) and trigeminal neuropathy, mainly neuralgia in the PA type (80.0%) with a higher statistical difference from other subtypes. The rate of tumour invasion into Meckel’s cave reached 70.3% in average, with the lowest rate in the PA type (25.0%). The rate of middle fossa extension was the highest in the TE type (59.5%). The middle fossa approach was considered to be ideal for UC and TE types because of easier access to the Meckel’s cave. Radical dissection without complications was difficult in the CS type. Both the anterior transpetrosal approach and the lateral suboccipital approach could be indicated in the PA type due to the rare invasion of Meckel’s cave and middle fossa, and frequent extension into the internal auditory meatus. Conclusions. This classification is useful to predict the relation between the tumour and the cranial nerves based on symptoms and images. The anterior transpetrosal approach could be used for all four subtypes and with an absolute indication in the UC and TE types showing middle fossa extension. Correspondence: Takeshi Kawase, M.D., Ph.D., Department of Neurosurgery, Keio University School of Medicine, 35 Shinano-machi, Shinjukuku, Tokyo 160-8582, Japan.     

Radiological predictive factors for regrowth of residual benign meningiomas

The pre- and postoperative radiological predictive factors for the regrowth of residual benign meningiomas were investigated in 80 of 327 patients who underwent first surgery for intracranial meningioma, who met the following conditions: residual tumor observed on postoperative imaging, follow up for more than 5 years or until regrowth of the residual tumor, histological diagnosis of World Health Organization grade I, and no additional therapy performed within 1 month after surgery. These 80 patients were divided into those with no regrowth during the follow-up period (Group A, n = 54) and those with regrowth (Group B, n = 26), and the clinical characteristics and pre- and postoperative imaging findings were compared. Univariate analysis of factors influencing regrowth showed 6 factors were significant: tumor size ≥4 cm (p = 0.043), tumor volume ≥30 cm(3) (p = 0.026), presence of edema (p = 0.036), unclear brain-tumor interface (p < 0.001), presence of a pial-cortical blood supply (p = 0.031), and residual tumor volume ≥3.0 cm(3) (p < 0.001). Multivariate analysis showed only residual tumor volume ≥3.0 cm(3) was significant (p = 0.001). Generally, the significant imaging findings on univariate analysis suggest malignant meningioma. Similar findings may be observed even in grade I cases, and residual tumors may regrow in such cases. The possibility is particularly high if the residual tumor volume exceeds 3.0 cm(3), so early radiotherapy should be performed to prevent regrowth.     

Surgical approaches to intraventricular meningiomas of the trigone

A case of a large intraventricular meningioma of the trigone is described. The tumor was removed by the transcallosal route. The neuropsychological sequelae of this approach are discussed. The value of other surgical approaches for meningiomas of the trigone is reviewed. The transcallosal approach originally described by Kempe and Blaylock is highly recommended.     

Middle fossa transpetrosal-transtentorial approaches for petroclival meningiomas selective pyramid resection and radicality

Summary Fourty-two patients with petroclival meningioma were operated upon by the middle fossa transpetrosal-transtentorial approaches since 1977. Half of those showed tumour extension into the middle fossa and one-third in the cavernous sinus. Seventeen (40%) had a large tumour of 40 mm in diameter or larger, and 8 of those had a broad attachment from the clivus to petrous pyramid of the temporal bone. The site of pyramid resection was selected from three types, depending on the tumour location and the patients' pre-operative hearing. There was no surgical mortality. Significant risk of lower cranial nerves palsy was minimal and useful hearing was preserved in 18 out of 21 patients. The follow-up, an average of 4 and a half years, showed tumours were completely eradicated in 32 patients (76%) and there was regrowfh in 3 (7%). Thirty-four patients (81%) were independent, 3 disabled and only one died of rapid tumour regrowth. The most influential factor on surgical results was the extent to which the tumour had invaded the brain stem. The presence or absence of arterial encasement and of peritumoural oedema on MRI were important in the selection for radical surgery.     

The historical perspective in approaches to the spheno-petro-clival meningiomas

Neurosurgical Review - The current literature regarding surgical treatment for tumors in the sphenopetroclival (SPC) region is merely scarce. Through a comprehensive literature review, we...     

Enlarged entry space for the transpetrosal approach

This report describes the removal of the roof of the external auditory meatus in approaching the tentorial edge, the cerebropontine angle, hippocampal brainstem lesions, and upper clival lesions. This procedure not only provides more space in approaching the tentorial edge or upper brainstem, it also provides a wider entry space for approaching posterior fossa lesions. This approach is also for lesions located lower than the tentorium or in the upper clivus. There is still some confusion about the method for removing the roof of the external auditory canal. We describe the clinical experience and comprehensive surgical procedures used on cadavers. Our extended temporal craniotomy technique using the removal of the roof of the external auditory meatus is a simple, safe, and useful method for obtaining a wider entry space to approach deep perimesencephalic lesions and the posterior fossa.     

Functional liver reserve parameters predictive for posthepatectomy complications

Background

Posthepatectomy complications have markedly decreased with advances in techniques and management; however, surgical risk to patients with injured livers is still not negligible. We evaluated several preoperative parameters of functional liver reserve tests in patients with various liver diseases as predictors of posthepatectomy complications. A comprehensive evaluation of preoperative liver functions is necessary for the prediction of the risk of posthepatectomy complications.

Methods

Over a 10-y period, we examined 442 patients who underwent hepatectomy for liver and biliary diseases. The patients' background liver diseases included chronic viral liver diseases in 211 patients, obstructive jaundice in 29 patients, and normal liver in 202 patients. Hepatectomy-related postoperative complications (i.e., long-term ascites, intra-abdominal infection, and hepatic failure) occurred in 115 (26%) patients. A multivariate logistic analysis was performed to detect the predictive parameters, and a multivariate linear regression analysis was performed to derive a predictive formula for complications.

Results

A univariate analysis identified 15 significant parameters associated with hepatectomy-related complications, and eight parameters (i.e., presence of chronic hepatic injury, clearance index by technetium-99 m galactosyl human serum albumin liver scintigraphy of ≥0.60, total bilirubin level of >1 mg/dL, serum hyaluronic acid level of ≥75 ng/mL, major hepatectomy, blood loss of ≥950 mL, operating time of ≥500 min, and combined resection of another organ or major vessel) were independent predictive factors identified in the multivariate analysis. Clearance index by technetium-99 m galactosyl human serum albumin liver, bilirubin level, hyaluronic acid level, and major hepatectomy were the parameters included in the predictive formula.

Conclusions

In the present study, we present a comprehensive formula based on the predictive parameters for hepatic complications for prospective assessment to avoid posthepatectomy morbidity.     

Different microsurgical approaches to meningiomas of the anterior cranial base

Introduction  

Meningiomas of the anterior skull base show specific characteristics, which render them difficult to handle. These tumors include olfactory groove, supra- and parasellar, anterior sphenoid ridge, cavernous sinus, and spheno-orbital meningiomas. Tumor localization and size, encasement of important structures as well as the extent of dural attachment may influence the decision for an adequate approach.     

Measurements of the skull base for transpetrosal surgery

To understand the anatomy and the surgical approaches to the petrous, 19 adult human skulls (38 specimens) were studied. The foramen spinosum, groove for greater petrosal nerve, superior and posterior margins of the internal auditory meatus, fissure for the endolymphatic sac, and anterior margin of the groove for sigmoid sinus were the constant, easily identifiable bony landmarks located strategically; they served as guides during the transpetrosal approach. Measurements between various points helped both to understand the local anatomy better and to decide the degree and direction of safe bony removal during transpetrosal surgery.