Minimally invasive subfrontal route for the resection of medial temporal region intrinsic tumors

Transorbital and supraorbital uniportal multicorridor approach to the orbit, anterior, middle and posterior cranial fossa: Anatomic study

Introduction

The transorbital route has been proposed for addressing orbital and paramedian skull base lesions. It can be complemented by further marginotomies, as per "extended-transorbital approach" and combined with others ventro-basal approaches featuring the concept of "multiportal surgery". Nevertheless, it cannot address some anatomical regions like the clinoid, carotid bifurcation and the Sylvian fissure. Therefore, we propose a combined transorbital and a supraorbital approach, attainable by a single infra-brow incision, and we called it "Uniportal multicorridor" approach.

Research question

The aim of our study is to verify its feasibility and deep anatomical targets through a cadaveric study.

Materials and methods

Anatomic dissections were performed at the Laboratory of ICLO Teaching and Research Center (Verona, Italy) on four formalin-fixed cadaveric heads injected with colored neoprene latex (8 sides). A stepwise dissection of the supraorbital and transorbital approaches (with an infra-brow skin incision) to the anterior tentorial incisura, clinoid area, lateral wall of the cavernous sinus, middle temporal fossa, posterior fossa, and Sylvian fissure is described.

Results

We analyzed the anatomic areas reached by the transorbital corridor dividing them as follow: lateral wall of the cavernous sinus, middle temporal fossa, posterior fossa, and Sylvian fissure; while the anatomic areas addressed by the supraorbital craniotomy were the clinoid area and the anterior tentorial incisura.

Conclusions

The described uniportal multi-corridor approach combines a transorbital corridor and a supraorbital craniotomy, providing a unique intra and extradural control over the anterior, middle, and posterior fossa, tentorial incisura and the Sylvian fissure, via an infra-brow skin incision.

Mini-craniotomy for intra-axial brain tumors: a comparison with conventional craniotomy in 306 patients harboring non-dural based lesions

The use of a mini-craniotomy approach involving linear skin incision and a bone flap of about 3 cm has been reported for several neurosurgical diseases, such as aneurysms or cranial base tumors. More superficial lesions, including intra-axial tumors, may occasionally raise concerns due to insufficient control of the tumor boundaries. The convenience of a minimally invasive approach to intrinsic brain tumors was evaluated by comparing 161 patients who underwent mini-craniotomy (MC) for intra-axial brain tumors with a group of 145 patients operated on by the same surgical team through a conventional craniotomy (CC). Groups were propensity-matched for age, preoperative condition, size and location of the tumor, and pathological diagnosis. Results were analyzed focusing on operative time, the extent of resection, clinical outcome, hospitalization time, and time to start adjuvant therapy. Mini-craniotomy was equally effective in terms of extent of resection (GTR: 70.9% in the MC group vs 70.5% in the CC group) but had shorter operative time (average: 165 min in the MC group vs 205 min in the CC group p < 0.001) and lower rate of postoperative complications both superficial (1.03% vs 6.5% in the CC group p = 0.009) and deep (4% in the MC group vs 5.5% in the CC group p = 0,47). No relationship was found between the size or location of the tumor and resection rate. The MC group had reduced hospitalization time (average: 5.8 days vs 7.6 in CC group p < 0.001) and faster access to adjuvant therapies. 92.5% of the MC patients, which were scheduled for treatment, started radiotherapy within 8 weeks after surgery as opposed to 84.1% in the CC group (p = 0.04). These findings support the increasing use of mini-craniotomy for intra-axial brain tumors.

Minimally Invasive Subfrontal Approach: How to Make it Safe and Effective from the Olfactory Groove to the Mesial Temporal Lobe

BACKGROUND

 Different surgical approaches have been developed to manage lesions of the anterior and middle skull base areas. Frontal, pterional, bifrontal, and fronto-orbito-zygomatic approaches are traditionally used to reach these regions. With advancements in the neurosurgical field, skull opening should be simple and as minimally invasive as possible, tailored on the surgical corridor to the target. The supraorbital approach and the "keyhole" concept have been introduced and popularized by Axel Perneczky starting from 1998 and are now considered a part of everyday practice. The extended possibilities of this surgical route, considering the reachable targets and surgical limits, are described and systematically analyzed, including a description of the salient surgical anatomy, presenting different illustrative cases.

METHODS AND RESULTS

 Different illustrative cases are presented and discussed to underline the potentials and limits of the minimally invasive subfrontal approach (MISFA) and the possibilities to tailoring the craniotomy on the basis of the targets: extra-axial lesions with different localizations (anterior roof of the orbit, olfactory groove, tuberculum sellae, medial third of the sphenoid wing, anterior and posterior clinoid process), deeper intra-axial lesions (gyrus rectus, medial temporal lobe-uncus-amygdala-anterior hippocampus), and vascular lesions (anterior communicating aneurysm). Each case has been preoperatively planned considering the anatomical and radiologic features and using virtual simulation software to tailor the best possible corridor to reach the surgical target.

CONCLUSIONS

 The MISFA is a safe multicorridor approach that can be used efficiently to manage lesions of the anterior and middle skull base areas with extremely low approach-related morbidity.

Surgical Management of Brain Cavernous Malformations

Surgical removal of accessible lesions is the only direct therapeutic approach for cerebral cavernous malformations (CCMs). The approach should be carefully evaluated according to clinical, anatomical, and neuroradiological assessment in order to both select the patient and avoid complications. In selected cases, a quantitative anatomical study with a preoperative simulation of surgery could be used to plan the operation. Neuronavigation, ultrasound, and neurophysiologic monitoring are generally required respectively to locate the CCMs and to avoid critical areas. The chapter describes all the possible surgical approaches for supratentorial, infratentorial, deep seated and brain stem CCMs. In any case before performing surgery, the physicians should always consider the benign nature of the lesions and the absolute necessity to avoid not only neurological deficits, but also a neuropsychological impairment that could affect the quality of life of the patients.