Glioblastoma complicated by fatal malignant acute ischemic stroke: MRI finding to assist in tricky surgical decision

BACKGROUND

In most cases, glioblastomas are associated with seizures, headaches, neurological deficits, aphasia, or bleeding. But these tumors are rarely associated with cerebral infarction and never so deadly.

CASE REPORT

A 40-year-old man presented with sudden morning isolated aphasia. One hour later, he developed a motor deficit at right upper member, quickly completed with a total right hemiplegia. Imaging studies revealed a left frontotemporal enhancing glioblastoma with a perilesional edema which produced an important mass effect on the posterior arm of the external capsule, on the primary motor cortex posteriorly and the entire sylvian valley anteriorly. Due to major surgical risks associated with left middle cerebral artery (MCA) inclusion and large edema, we decided to postpone the tumor removal and introduce quickly high concentrations of steroids. Twenty-four hours after his admittance, the patient presented a sudden impaired consciousness, coma, and a left mydriasis. A brain magnetic resonance image (MRI) revealed a left malignant MCA infarction, deadly for the patient.

CONCLUSION

To our knowledge, glioblastomas complicated by fatal ischemic stroke have not been reported. We discuss the pathology of such an event and try to figure out if it was predictable based on MRI finding, and inevitable with precocious surgery.

Multimodal angiographic assessment of cerebral arteriovenous malformations: a pilot study

PURPOSE

We describe our protocol of three-dimensional (3D) Roadmap intracranial navigation and image fusion for analysis of the angioarchitecture and endovascular treatment of brain arteriovenous malformations (AVMs).

METHODS

We performed superselective catheterization of brain AVMs feeders under 3D-Roadmap navigation. Angiograms of each catheterized artery on two registered orthogonal views were transferred to the imaging workstations, and dedicated postprocessing imaging software allowed automated multiple overlays of the arterial supply of the AVM superselective acquisitions on the global angiogram in angiographic or 3D views and on coregistered MRI datasets.

RESULTS

11 untreated brain AVMs (4 with hemorrhagic presentation) were explored. The superselective acquisitions were performed under 3D-Roadmap navigation in 74 arteries, for a total of 79 targeted arteries. Imaging analysis was available at table side or postoperatively for discussion of the therapeutic strategy. No complications occurred during superselective catheterization. The accuracy of the coregistration of angiogram and MRI was submillimetric after automated mutual information coregistration, with manual re-registration by the physicians.

CONCLUSIONS

Superselective angiograms acquired under 3D-Roadmap navigation can be postprocessed with multiple overlays. The fluoroscopic navigation under 3D-Roadmapping and the coregistration of 3D rotational angiography, selective angiography, and 3D MR datasets appears reliable with millimeter accuracy, and could be implemented in the critical brain AVM embolization setting to allow refined analysis of AVM angioarchitecture.

Transoral robotic-assisted skull base surgery to approach the sella turcica: cadaveric study

Transoral robotic surgery (TORS) offers new possibilities that have not been experimented in the field of minimally invasive skull base neurosurgery. We propose to evaluate the feasibility of transoral approach to the sella turcica with the da Vinci system on cadavers. We performed four robot-assisted dissections on human fresh cadavers in order to reach the pituitary fossa by the oral cavity. Cavum mucosa dissection was performed by the head and neck surgeon at the console and then the sphenoid was drilled by the neurosurgeon at the bedside, with intraoperative fluoroscopy and a "double surgeon" control. Mucosa closure was attempted with robotic arms. We succeeded in performing a sellar opening in all cadavers with a minimally invasive approach, as the hard palate was never drilled. The video endoscope offered a large view inside the sphenoidal sinus, as observed in transnasal endoscopy, but with 3D visualization. The camera arm could be inserted into the sphenoidal sinus, and instrument arms in the pituitary fossa. Operative time to reach the pituitary fossa was approximately 60 min in all procedures: 20 min of initial setup, 10 min of mucosal dissection, and 30 min of sphenoid surgery. New anatomical landmarks were defined. Advantages and pitfalls of such an unpublished technique were discussed. This is the first cadaveric study reported da Vinci robotic transoral approach to the sella turcica with a minimally invasive procedure. This innovative technique may modify the usual pituitary adenoma removal as the sella is approached infero-superiorly.

Targeting accuracy of transcranial magnetic resonance-guided high-intensity focused ultrasound brain therapy: a fresh cadaver model

OBJECT

This work aimed at evaluating the accuracy of MR-guided high-intensity focused ultrasound (MRgHIFU) brain therapy in human cadaver heads.

METHODS

Eighteen heads of fresh human cadavers were removed with a dedicated protocol preventing intracerebral air penetration. The MR images allowed determination of the ultrasonic target: a part of the thalamic nucleus ventralis intermedius implicated in essential tremor. Osseous aberrations were corrected with simulation-based time reversal by using CT data from the heads. The ultrasonic session was performed with a 512-element phased-array transducer system operating at 1 MHz under stereotactic conditions with thermometric real-time MR monitoring performed using a 1.5-T imager.

RESULTS

Dissection, imaging, targeting, and planning have validated the feasibility of this human cadaver model. The average temperature elevation measured by proton resonance frequency shift was 7.9°C ± 3°C. Based on MRI data, the accuracy of MRgHIFU is 0.4 ± 1 mm along the right/left axis, 0.7 ± 1.2 mm along the dorsal/ventral axis, and 0.5 ± 2.4 mm in the rostral/caudal axis.

CONCLUSIONS

Despite its limits (temperature, vascularization), the human cadaver model is effective for studying the accuracy of MRgHIFU brain therapy. With the 1-MHz system investigated here, there is millimetric accuracy.

Conservative management of a large occipital extradural haematoma

A 26-year-old male presented with a mild confusion and hemianopsia after traumatic brain injury. Cerebral CT-scan revealed a 62.5 cm(3) left occipital extradural haematoma (EDH). Although conventional neurosurgical management would have been to evacuate the haematoma, a conservative strategy was preferred, and the patient made a total recovery.

MR-guided adaptive focusing of therapeutic ultrasound beams in the human head

PURPOSE

This study aims to demonstrate, using human cadavers the feasibility of energy-based adaptive focusing of ultrasonic waves using magnetic resonance acoustic radiation force imaging (MR-ARFI) in the framework of non-invasive transcranial high intensity focused ultrasound (HIFU) therapy.

METHODS

Energy-based adaptive focusing techniques were recently proposed in order to achieve aberration correction. The authors evaluate this method on a clinical brain HIFU system composed of 512 ultrasonic elements positioned inside a full body 1.5 T clinical magnetic resonance (MR) imaging system. Cadaver heads were mounted onto a clinical Leksell stereotactic frame. The ultrasonic wave intensity at the chosen location was indirectly estimated by the MR system measuring the local tissue displacement induced by the acoustic radiation force of the ultrasound (US) beams. For aberration correction, a set of spatially encoded ultrasonic waves was transmitted from the ultrasonic array and the resulting local displacements were estimated with the MR-ARFI sequence for each emitted beam. A noniterative inversion process was then performed in order to estimate the spatial phase aberrations induced by the cadaver skull. The procedure was first evaluated and optimized in a calf brain using a numerical aberrator mimicking human skull aberrations. The full method was then demonstrated using a fresh human cadaver head.

RESULTS

The corrected beam resulting from the direct inversion process was found to focus at the targeted location with an acoustic intensity 2.2 times higher than the conventional non corrected beam. In addition, this corrected beam was found to give an acoustic intensity 1.5 times higher than the focusing pattern obtained with an aberration correction using transcranial acoustic simulation-based on X-ray computed tomography (CT) scans.

CONCLUSIONS

The proposed technique achieved near optimal focusing in an intact human head for the first time. These findings confirm the strong potential of energy-based adaptive focusing of transcranial ultrasonic beams for clinical applications.

Study of dural suture watertightness: an in vitro comparison of different sealants

BACKGROUND

CSF leakages constitute a major complication of intradural procedures, especially for posterior fossa and skull base surgery. Dural suture watertightness is a decisive issue, and neurosurgeons routinely use different products to reinforce their dural closure. We have designed an experimental system capable of testing CSF leak pressure levels in order to compare two types of sutures in vitro and particularly four different sealants.

METHODS

Twenty-five fresh human cadaveric dural samples were removed and prepared for testing in a pressure chamber system connected to a hydraulic pressure motor. CSF leak levels were objectively registered. First, simple interrupted stitches were compared to running simple closure on 50-mm linear suture. Secondly, four sealants (two sealants/glues, Bioglue®, Duraseal®; two haemostatics, Tachosil®, Tissucol®) were tested. Statistical analysis was performed with paired Student's t-test.

RESULTS

No significant difference between interrupted closure and running suture was observed (p = 0.079). All sealants increased the watertightness of the suture significatively. However, comparison of the means of the differences for each product revealed large variations. In the conditions of our experiment, one sealant (Duraseal®) and one haemostatic (Tachosil®) seemed to show better results. We observed two different types of leakage: at the dura-sealant interface and through the sealant itself.

CONCLUSIONS

We have developed an experimental device capable of testing dural closure watertightness. Interrupted stitch suturing seemed no different from running simple closure. On the contrary, the sealants tested show different watertightness capacities.

In vivo bubble nucleation probability in sheep brain tissue

Gas nuclei exist naturally in living bodies. Their activation initiates cavitation activity, and is possible using short ultrasonic excitations of high amplitude. However, little is known about the nuclei population in vivo, and therefore about the rarefaction pressure required to form bubbles in tissue. A novel method dedicated to in vivo investigations was used here that combines passive and active cavitation detection with a multi-element linear ultrasound probe (4-7 MHz). Experiments were performed in vivo on the brain of trepanated sheep. Bubble nucleation was induced using a focused single-element transducer (central frequency 660 kHz, f-number = 1) driven by a high power (up to 5 kW) electric burst of two cycles. Successive passive recording and ultrafast active imaging were shown to allow detection of a single nucleation event in brain tissue in vivo. Experiments carried out on eight sheep allowed statistical studies of the bubble nucleation process. The nucleation probability was evaluated as a function of the peak negative pressure. No nucleation event could be detected with a peak negative pressure weaker than -12.7 MPa, i.e. one order of magnitude higher than the recommendations based on the mechanical index. Below this threshold, bubble nucleation in vivo in brain tissues is a random phenomenon.

In vivo bubble nucleation probability in sheep brain tissue

Gas nuclei exist naturally in living bodies. Their activation initiates cavitation activity, and is possible using short ultrasonic excitations of high amplitude. However, little is known about the nuclei population in vivo, and therefore about the rarefaction pressure required to form bubbles in tissue. A novel method dedicated to in vivo investigations was used here that combines passive and active cavitation detection with a multi-element linear ultrasound probe (4-7 MHz). Experiments were performed in vivo on the brain of trepanated sheep. Bubble nucleation was induced using a focused single-element transducer (central frequency 660 kHz, f-number = 1) driven by a high power (up to 5 kW) electric burst of two cycles. Successive passive recording and ultrafast active imaging were shown to allow detection of a single nucleation event in brain tissue in vivo. Experiments carried out on eight sheep allowed statistical studies of the bubble nucleation process. The nucleation probability was evaluated as a function of the peak negative pressure. No nucleation event could be detected with a peak negative pressure weaker than -12.7 MPa, i.e. one order of magnitude higher than the recommendations based on the mechanical index. Below this threshold, bubble nucleation in vivo in brain tissues is a random phenomenon.

In vivo accuracy of two intraparenchymal intracranial pressure monitors

PURPOSE

To evaluate the in vivo accuracy of the new Pressio(®) device for intraparenchymal monitoring of intracranial pressure (ICP) versus the Codman(®) device and intraventricular measurement external ventricular drainage (EVD).

METHODS

Data were collected retrospectively for 30 consecutive patients admitted into a 25-bed neurosurgical intensive care unit of a university hospital between January and December 2009. Patients received both intraventricular and intraparenchymal ICP monitoring with Pressio(®) (n = 15) or Codman(®) (n = 15).

RESULTS

We obtained 3,089 data points from the 30 patients. Mean difference between intraparenchymal and EVD pressure (bias) was -0.6 mmHg, and limits of agreement (1.96 SD of the bias) were -8.1 to 6.9 mmHg with Pressio(®) and 0.3 mmHg with limits of agreement of -6.7 to 7.1 mmHg with Codman(®) (NS). The temporal difference was -0.7 ± 1.6 mmHg/100 h of monitoring with Pressio(®) and 0.1 ± 1.6 mmHg/100 h of monitoring with Codman(®) over the study period (NS).

CONCLUSIONS

Intraparenchymal pressure measured with both transducers approximates intraventricular cerebrospinal fluid pressure with an accuracy of ±7 mmHg.

[The mystery of prehistoric trepanations: Is neurosurgery the world eldest profession?]

Trepanation is known to be the first surgical procedure ever performed. Its origins date from the Neolithic Age in Europe and the operation was particularly performed in South America at the Pre-Colombian era, a few thousand years later. Based on many archeological studies on trepanned skulls, we compare the differences and similarities of these two periods through epidemiological, topographical, and technical approaches. Signs of bony regeneration are assessed in an attempt to understand the postoperative survival of trepanned patients. The literature in surgery and archeology does not mention the possible relation between trepanations and growing skull fractures. However, it is reasonable to think that these cranial holes, occurring after a pediatric skull fracture, could mimic real trepanation orifices. The possible connections between these two entities are discussed. The etiological hypotheses on prehistoric trepanation are reviewed.