Timothée Jacquesson

The fully endoscopic supraorbital trans-eyebrow keyhole approach to the anterior and middle skull base

BackgroundThe purely endoscopic eyebrow supraorbital approach is an alternative to both the endoscopic endonasal and eyebrow microsurgical routes to the anterior and middle cranial base. It combines an enhanced visualization provided by the endoscope and the absence of cerebrospinal fluid (CSF) leaks and nasal complications.MethodsA trans-eyebrow 2-cm craniotomy is designed to allow the placement of a straight endoscope and visualize the skull base from the cribriform plate to the mesiotemporal lobe.ResultVisualization is considerably improved, while the keyhole mini-invasive concept is respected.ConclusionThe purely endoscopic eyebrow supraorbital keyhole approach is a valuable and alternative minimally invasive route to anterior and middle skull base lesions.

Which Routes for Petroclival Tumors? A Comparison Between the Anterior Expanded Endoscopic Endonasal Approach and Lateral or Posterior Routes

OBJECTIVEnPetroclival tumors remain a surgical challenge. Classically, the retrosigmoid approach (RSA) has long been used to reach such tumors, whereas the anterior petrosectomy (AP) has been proposed to avoid crossing cranial nerves. More recently, the endoscopic endonasal approach has been expanded (i.e., EEEA) to the petroclival region. We aimed to compare these 3 approaches to help in the surgical management of petroclival tumors.nnnMETHODSnPetroclival approaches were performed on 5 specimens after they were prepared with formaldehyde colored via latex injection.nnnRESULTSnThe EEEA provides a simple straightforward route to the clivus, but reaching the petrous apex requires the surgeon to circumvent the internal carotid artery either via a medial transclival, an inferior transpterygoid, or a lateral variant through the Meckels cave. In contrast, the AP offers a narrow direct superolateral access to the petroclival region crossed by the trigeminal nerve. Finally, the RSA provides a wide simple and quick exposure of the cerebellopontine angle, but access to the petroclival region needs the surgeon to deal with the V(th) to XI(th) cranial nerves.nnnDISCUSSION/CONCLUSIONnThe EEEA should be preferred for extradural midline tumors (chordomas, chondrosarcomas) or for cystic lesions when drainage is essential. The AP could be optimal for the radical removal of intradural vascularized tumors (meningiomas) with intrapetrous or supratentorial extensions. The RSA retains an advantage for small or cystic tumors near the internal acoustic meatus. The skull base surgeon has to master all of these routes to choose the more appropriate one according to the surgical objective, the tumor characteristics, and the patients medical status.

Anatomic comparison of anterior petrosectomy versus the expanded endoscopic endonasal approach: interest in petroclival tumors surgery.

PurposeSince the petroclival region is deep-seated with close neurovascular relationships, the removal of petroclival tumors still represents a fascinating surgical challenge. Although the classical anterior petrosectomy (AP) offers a meaningful access to this petroclival region, the expanded endoscopic endonasal approach (EEEA) recentlyxa0leads to overcome difficulties from trans-cranial approaches. Herein, we present an anatomic comparison of AP versus EEEA. We aim to describe the limits of these both approaches helping the choice of the optimal surgical route for petroclival tumors.MethodsSix fresh cadaveric heads were harvested and injected with colored latex. Each approach was step-by-step detailed until its final surgical exposure.ResultsThe AP provided a narrow direct supero-lateral access to the petroclival area that can also reach the cavernous sinus, the retrochiasmatic region and perimesencephalic cisterns. However, this corridor anterior to the internal acoustic meatus passed on each side of the trigeminal nerve. Moreover, tumor extensions toward the foramenxa0jugularis, inside the clivus or behind the internal acoustic meatus were difficult to control. The EEEA brought a straightforward access to the clivus but the petrous apex was hidden behind the internal carotid artery. Several variants were described: a medial transclival, a lateral through the Meckel’s cave and an inferior trans-pterygoid route. Elsewhere, tumor extension behind the internal acoustic meatus or above the tentorium could not be satisfactorily assessed.Discussion and conclusionPA and EEEA have their own limits in reaching the petroclival region in accordance with the tumor characteristics. The AP should be preferred for radical removal of middle-sized petrous apex intradural tumors like meningiomas. The EEEA would be of interest for extradural midline tumors like chordomas or for petrous apex cysts drainage.

The minimally invasive endoscopic management of septated chronic subdural hematomas: surgical technique.

BackgroundFibrin membranes and compartmentalization within the subdural space are a frequent cause of failure in the treatment of chronic subdural hematomas (CSH). This specific subtype of CSH classically requires craniotomy, which carries significant morbidity and mortality rates, particularly in elderly patients. In this work, we describe a minimally invasive endoscopic alternative.MethodsUnder local scalp anesthesia, a rigid endoscope is inserted through a parietal burr hole in the subdural space to collapse fibrin septa and cut the internal membrane. It also allows cauterization of active bleedings and the placement of a drain under direct visualization.ConclusionsThe endoscopic treatment of septated CSH represents a minimally invasive alternative to craniotomy especially for the internal membranectomy.

What is the dorsal median sulcus of the spinal cord? Interest for surgical approach of intramedullary tumors

PurposeFor intramedullary tumor (IMT) surgery, a balance has to be found between aggressively resecting the tumor and respecting all the sensory and motor pathways. The most common surgical approach is through the dorsal median sulcus (DMS) of the spinal cord. However, the precise organization of the meningeal sheats in the DMS remains obscure in the otherwise well-described anatomy of the spinal cord. A better understanding of this architecture may be of benefit to IMT surgeon to spare the spinal cord.MethodsThree spinal cords were studied. The organization of the spinal cord meninges in the DMS was described via macroscopic, microsurgical and optical microscopic views. A micro dissection of the DMS was also performed.ResultsNo macroscopic morphological abnormalities were observed. With the operative magnifying lens, the dura was opened, the arachnoid was removed and the pia mater was cut to access the DMS. The histological study showed that the DMS was composed of a thin rim of capillary-carrying connective tissue extending from the pia mater and covering the entire DMS. There was no true space between the dorsal columns, no arachnoid or crossing axons either.ConclusionOur work indicates that the DMS is not a sulcus but a thin blade of collagen extending from the pia mater. Its location is given by tiny vessels coming from the surface towards the deep. Thus, the surgical corridor has to follow the DMS as closely as possible to prevent damage to the spinal cord during midline IMT removal.

Total removal of a trigeminal schwannoma via the expanded endoscopic endonasal approach. Technical note.

BackgroundBecause of their deep location surrounded by closed numerous neurovascular structures, skull base tumors of the cavernous sinus are still difficult to manage. Recently, the endoscopic endonasal approach commonly used for pituitary tumor resection has been “expanded” to the parasellar, infratemporal and orbital compartments with some advantages compared to the intracranial route.MethodsThe authors reported the case of a 49-year-old male presenting a large extradural tumor of the left cavernous sinus with extensions toward the orbit, sphenoid sinus and infratemporal fossa. His ophthalmological examination was normal, and the body CT scan revealed no primary neoplasm.ResultsIn this operative video, the approach is described step by step with surgical nuances. The endoscopy provided a close-up panoramic view and various angles of vision. Also, it avoided an invasive craniotomy, cerebral retraction and cranial nerves damages. Thus, it allowed the total removal of this tumor originating from the maxillary branch of the trigeminal nerve. The pathologic examination confirmed a schwannoma.ConclusionThe expanded endoscopic endonasal approach provides an interesting corridor to cavernous sinus tumors with satisfactory control of extensions inferiorly toward the infratemporal fossa, anteriorly via the superior orbital fissure and medially within the sphenoid. Finally, the skull base surgeon has to master this anterior endoscopic route as well as all the other “open” transcranial skull base approaches to propose the best surgical route fitting the tumor characteristics.

MRI Tractography Detecting Cranial Nerve Displacement in a Cystic Skull Base Tumor

A 37-year-old man came to our neurosurgical department with a 2-month history of a progressive invalidating balance disorder. Cerebral magnetic resonance imaging found a T2-weighted hypersignal lesion of the right cerebellopontine angle that severely compressed the brainstem, however the position of cranial nerves was not clearly identified. The new MRI diffusion tool, tractography, allowed to reconstruct the trajectory of cranial nerves that were displaced by the tumor. As such, the acoustic facial bundle was severely flattened posteriorly and superiorly, while the lower nerves were pushed inferiorly. Effective neurosurgical decompression was performed and confirmed the position of cranial nerves V-XII. The patient was discharged and returned home without any cranial nerve deficit. This case illustrates how advances in imaging can now better describe the anatomy surrounding brain tumors and make surgery safer to the benefit of patients.

Overcoming Challenges of Cranial Nerve Tractography: A Targeted Review

BACKGROUNDnDiffusion imaging tractography caught the attention of the scientific community by describing the white matter architecture in vivo and noninvasively, but its application to small structures such as cranial nerves remains difficult. The few attempts to track cranial nerves presented highly variable acquisition and tracking settings.nnnOBJECTIVEnTo conduct and present a targeted review collecting all technical details and pointing out challenges and solutions in cranial nerve tractography.nnnMETHODSnA targeted review of the scientific literature was carried out using the MEDLINE database. We selected studies that reported how to perform the tractography of cranial nerves, and extracted the following: clinical context; imaging acquisition settings; tractography parameters; regions of interest (ROIs) design; and filtering methods.nnnRESULTSnTwenty-one published articles were included. These studied the optic nerves in suprasellar tumors, the trigeminal nerve in neurovascular conflicts, the facial nerve position around vestibular schwannomas, or all cranial nerves. Over time, the number of MRI diffusion gradient directions increased from 6 to 101. Nine tracking software packages were used which offered various types of tridimensional display. Tracking parameters were disparately detailed except for fractional anisotropy, which ranged from 0.06 to 0.5, and curvature angle, which was set between 20° and 90°. ROI design has evolved towards a multi-ROI strategy. Furthermore, new algorithms are being developed to avoid spurious tracts and improve angular resolution.nnnCONCLUSIONnThis review highlights the variability in the settings used for cranial nerve tractography. It points out challenges that originate both from cranial nerve anatomy and the tractography technology, and allows a better understanding of cranial nerve tractography.

The 360 photography: a new anatomical insight of the sphenoid bone. Interest for anatomy teaching and skull base surgery.

Skull base architecture is tough to understand because of its 3D complex shape and its numerous foramen, reliefs or joints. It is especially true for the sphenoid bone whom central location hinged with most of skull base components is unique. Recently, technological progress has led to develop new pedagogical tools. This way, we bought a new real-time three-dimensional insight of the sphenoid bone that could be useful for the teacher, the student and the surgeon. High-definition photography was taken all around an isolated dry skull base bone prepared with Beauchêne’s technique. Pictures were then computed to provide an overview with rotation and magnification on demand. From anterior, posterior, lateral or oblique views and from in out looks, anatomical landmarks and subtleties were described step by step. Thus, the sella turcica, the optic canal, the superior orbital fissure, the sphenoid sinus, the vidian canal, pterygoid plates and all foramen were clearly placed relative to the others at each face of the sphenoid bone. In addition to be the first report of the 360 Photography tool, perspectives are promising as the development of a real-time interactive tridimensional space featuring the sphenoid bone. It allows to turn around the sphenoid bone and to better understand its own special shape, numerous foramen, neurovascular contents and anatomical relationships. This new technological tool may further apply for surgical planning and mostly for strengthening a basic anatomical knowledge firstly introduced.

Disappearance of FDG uptake on PET scan after antimicrobial therapy could help for the diagnosis of Coxiella burnetii spondylodiscitis

A 55u2005year-oldxa0man was admitted for worsening of a chronic low back pain associated with L4-L5 anterolisthesis, despite taking non-steroidal anti-inflammatory drugs for several months. He had a medical history of high blood pressure and obesity (body mass index, 37u2005kg/m2). He lived in the countryside but had no direct contact with animals except his dog. There were no fever, chills, sweats or weight loss. C reactive protein (CRP) was <2.9u2005mg/L. Radiographs showed L4-L5 anterolisthesis with endplate erosions and bony sclerosis (figure 1A). On MRI (figure 1B), there was a significant enhancement of L4-L5 vertebral endplates and paravertebral soft tissues. Positron emission tomography (PET) CT scan showed an intense uptake of the L4-L5 space (figure 1C). …