A Holographic Augmented Reality Interface for Visualizing of MRI Data and Planning of Neurosurgical Procedures.

The recent introduction of wireless head-mounted displays (HMD) promises to enhance 3D image visualization by immersing the user into 3D morphology. This work introduces a prototype holographic augmented reality (HAR) interface for the 3D visualization of magnetic resonance imaging (MRI) data for the purpose of planning neurosurgical procedures. The computational platform generates a HAR scene that fuses pre-operative MRI sets, segmented anatomical structures, and a tubular tool for planning an access path to the targeted pathology. The operator can manipulate the presented images and segmented structures and perform path-planning using voice and gestures. On-the-fly, the software uses defined forbidden-regions to prevent the operator from harming vital structures. In silico studies using the platform with a HoloLens HMD assessed its functionality and the computational load and memory for different tasks. A preliminary qualitative evaluation revealed that holographic visualization of high-resolution 3D MRI data offers an intuitive and interactive perspective of the complex brain vasculature and anatomical structures. This initial work suggests that immersive experiences may be an unparalleled tool for planning neurosurgical procedures.

Regenerated Nerve Defects with a Nerve Conduit Containing Dental Pulp Stem Cells in Pigs: An Immunohistochemical and Electrophysiological Evaluation.

BACKGROUND: Dental pulp stem cells (DPSCs) present an exciting new tool in the field of peripheral nerve regeneration due to their close embryonic origin. In this study, we examined their potential in pigs, using biodegradable collagen conduits filled with DPSCs. To our knowledge, this is the first time DPCSs are tested for peripheral nerve regeneration in such large animal model. MATERIALS AND METHODS: The second lateral incisor was extracted from every animal's lower jaw and stem cells were isolated and cultured. The collagen nerve conduits containing the DPSCs were subsequently transplanted into the transected fifth and sixth intercostal nerves, while the seventh intercostal nerve was used as a control and no stem cells were added on the respective collagen conduit. RESULTS: A histological examination was performed on the 3rd and 6th postoperative months and showed the gradual development of neural tissue and immunohistochemical expression of neuron-specific enolase. An electrophysiological study was performed on the 6th postoperative month and showed similar potentials between the stem cell infusion region (5 ± 0.04 units) and their proximal stumps (5 ± 0.05 units) and slightly smaller potentials in the respective distal stumps (4 ± 0.045 units). CONCLUSION: The nerves where DPSCs were injected exhibited morphological and functional recovery, in contrast to the control nerves where no recovery was detected; thus, there is a first evidence of the therapeutic potential of DPSCs in peripheral nerve regeneration.

The evaluation of the usefulness of CO2 laser in microsurgical resection of brain tumors.

Background: Since its introduction to surgery, the CO2 laser has been used in the treatment of various neurosurgical pathologies as it combines cutting, vaporizing, and coagulating properties in one tool and has a safe penetration depth. In this case series of 29 patients, we present the evaluation of the usefulness of the closed system type - sealed tube surgical CO2 laser in the surgical removal of brain tumors. Methods: The Sharplan 40C model SurgiTouch, sealed tube type CO2 laser, was used in the resection of 29 brain tumors; 13 meningiomas, six metastases, nine gliomas, and one acoustic neuroma. The same senior surgeon (BT) assessed and classified the benefit provided by the CO2 laser in the resection of the neoplasms to considerable (Group 1), moderate (Group 2), and poor (Group 3). Results: Group 1 included 14 patients with 13 meningiomas and one acoustic neuroma, Group 2 included six patients, all of whom had metastases, and Group 3 included nine patients of which six had glioblastoma and three astrocytoma. No complications or technical problems occurred due to the use of the CO2 laser. Conclusion: The CO2 laser is a valuable complementary tool in brain tumor surgery displaying high efficacy and practicality in the resection of neoplasms which are fibrous and have hard consistency. It has high acquisition and maintenance cost and cannot replace the bipolar diathermy. The newest generation of flexible CO2 laser fiber provides more ergonomy and promises new perspectives of its neurosurgical use in the modern era.

The Mini-Spheno-Supraorbital Craniotomy for Treatment of Ruptured Anterior Circulation Aneurysms.

Objective:Yasargil introduced the pterional approach mainly for clipping of anterior circulation (AC) aneurysms. We implemented the mini-spheno-supraorbital (MSS) craniotomy, changing the shape and reducing the size of the classical pterional craniotomy. The literature on clipping ruptured AC aneurysms through reduced-in-size craniotomies is sparse. This study aims to describe the technique and present our experience in clipping ruptured AC aneurysms through the MSS approach. Materials and methods: The MSS craniotomy was used in 114 cases of clipping ruptured AC aneurysms. A single burr hole was placed at the "keyhole" and an ellipsoid bone flap in the spheno-supraorbital region was raised. The tabula interna was thinned circumferentially, the roof of the orbit was flattened. Among aneurysm clipping, the lamina terminalis and the subarachnoid basal cisterns were opened. The imaging modality, the severity of the subarachnoid hemorrhage (SAH) according to Hunt & Hess (H&H), the size of the bone flap, the surgery duration and the aneurysm obliteration rate seen at the postoperative DSA were examined. Results:Out of all patients in the study, 71% had exclusively CT-angiogram as initial imaging and suffered low-grade (H&H I°) SAH (71%). The mean size of the bone flap was 1.6 x 4.5 cm (1.3 x 4.3 - 2 x 8.5 cm). The approach allowed adequate 360°-dissection, sufficient proximal and distal control, brain relaxation though laminoterminotomy and opening of the basal cisterns. The mean duration from skin incision to clip application was 130 minutes (64-236 mins). Total obliteration rate was 97.3%. Conclusion:The MSS craniotomy is feasible in terms of safety and speed for clipping of ruptured AC aneurysms especially in lower-grade SAH.

Spinal epidural abscess in a young girl without risk factors.

Spinal epidural abscess (SEA) is a rare infection associated with well-established risk factors mainly in adults. We describe an 11-year-old girl without any known risk factors who presented with fever and localized spinal tenderness in the lumbar area and was diagnosed with spinal MRI as suffering from a posterior SEA extending between T11 and L4. She was successfully managed with sequential intravenous and oral antibiotics along with minimally invasive surgery without laminectomy. Methicillin-sensitive Staphylococcus aureus was the responsible pathogen isolated at surgery. Immediate institution of antibiotics, spinal MRI, and well-timed neurosurgical consultation are mandatory for a favorable outcome in cases of SEA in children.

The Use of Real-Time 3D Intraoperative Ultrasound "Angiography" in Localization and Occlusion Control of a Ruptured Mycotic Aneurysm: A Case Report.

BACKGROUND: Infectious (mycotic) aneurysms are rare with high mortality and are most commonly found at the distal branches of the middle cerebral artery (MCA). Because aneurysms of the distal MCA are located deep in the Sylvian fissure and are small in size, intraoperative identification and safe clip occlusion of these aneurysms are challenging. Thus, the use of intraoperative imaging and navigation can be beneficial. We describe the use of intraoperative real-time 3D ultrasound "angiography" (3D-iUS) in localizing and occlusion control of a ruptured MCA M3 segment mycotic aneurysm. To our knowledge, its application in the surgery of a ruptured mycotic distal MCA aneurysm is not yet reported. CLINICAL PRESENTATION: A 54-year-old woman with a history of septic thrombophlebitis treated with long-term antibiotic therapy presented with sudden onset of headaches, dysphasia, and seizures. Computed tomography (CT) revealed subarachnoid hemorrhage in the distal portion of the left Sylvian fissure. Digital subtraction angiography (DSA) showed an aneurysm at the peripheral branch of the M3 segment of the MCA with characteristics of an infectious aneurysm. A microsurgical treatment was decided. 3D-iUS scan showed an aneurysm within the Sylvian fissure at a depth of 5 cm. The aneurysm was clipped and a repeated 3D-iUS scan showed total occlusion of the aneurysm and patency of the parent artery. The intraoperative findings were confirmed with a postoperative DSA. CONCLUSION: Our case report shows that real-time 3D-iUS, despite its limitations, is an important tool to locate and ascertain the successful clip occlusion of an aneurysm, especially when intraoperative angiography (IA) and indocyanine green (ICG) videoangiography are not available due to low-income settings.

Volumetric data of normal nucleus accumbens from magnetic resonance imaging scans.

Backgrounds and aims: The nucleus accumbens (AcN) belongs to the ventral striatum and it is involved in several neuropsychiatric disorders. In contrast to other subcortical structures, the number of morphometric studies that concern the healthy nucleus is limited. This study aims to investigate the normal volumetric data of the AcN as derived from a large number of manually segmented magnetic resonance imaging (MRI) scans. Methods: The measurements were performed in 106 MRI scans of healthy adults. The resulting volumes have been analyzed for differences related to hemisphere, sex and age. Results: The mean AcN volume was estimated at 473.3 mm3 (SD=±106.8). A slight interhemispheric difference in favor of the left side was found, the value of which was, however, within the limits of the method error. There were no sexual dimorphism signs concerning both the raw and the normalized volumes. A negative correlation between volumes and age was observed only in males. Conclusions: The study provides normal volumetric data of the AcN, useful in the conduct of comparative imaging and post-mortem studies in pathological conditions.

Magnetic Resonance Imaging patterns in central nervous system lymphomas: A pictorial review.

Five distinctive Magnetic Resonance Imaging (MRI) patterns of Central Nervous System Lymphomas (CNSL) are introduced in this pictorial essay - in an attempt to differentiate lymphoma from other abnormalities with similar MRI appearance, - namely a. solitary supratentorial, b. multiple supratentorial, c. infratentorial, d. intravascular, and e. extraparencymal. Recognition of a specific imaging pattern on brain MR imaging, may facilitate the early diagnosis and prompt treatment initiation, thus improving prognosis of brain lymphoma.

Clipping of a basilar tip aneurysm using hypothermia and circulatory arrest: a case report.

Treatment of complex and giant aneurysms remains challenging despite modern endovascular and microsurgical techniques. We report the first case of microsurgical clipping of a complex basilar tip aneurysm under circulatory arrest and hypothermia performed in Greece. A 52-year-old patient presented with a Hunt and Hess Grade 4 subarachnoid hemorrhage. The digital subtraction angiography revealed a complex basilar tip aneurysm. Due to aneurysm complexity, we decided for microsurgical clipping under hypothermia and circulatory arrest. We performed a right pterional craniotomy with orbitozygomatic osteotomy. The patient was then put on heart-lung-machine. Following hypothermia and circulatory arrest, the aneurysm was clipped with its complete occlusion. The patient was discharged with no neurological deficits. Clipping of complex aneurysms under hypothermia and cardiac arrest performed by experienced team is a safe alternative when endovascular therapy or bypass technique is not feasible.

Meningioma of the conus medullaris mimicking neurofibroma--possibly radiation induced.

BACKGROUND CONTEXT: Radiation-induced meningiomas (RIMs) of the brain are the most common RIMs. However, there has been no report in the literature of an RIM of the spine. Conus medullaris is a favorite site for ependymomas, whereas it is an extremely rare location for meningiomas. Dumbbell-shaped configuration is typical for nerve sheath tumors; however, it is very rarely seen in meningiomas. PURPOSE: To describe imaging findings of a possibly RIM at the level of the conus medullaris mimicking a neurofibroma. STUDY DESIGN: A 60-year-old male with 6-year history of irradiated urinary bladder cancer presented with paraparesis. METHODS: Radiography, computed tomography, and magnetic resonance imaging of the thoracolumbar spine were undertaken. RESULTS: Radiography showed widening of intervertebral foramina at T12-L1 level. Computed tomography and magnetic resonance imaging disclosed a lobulated intradural mass at the level of the conus medullaris causing widening and scalloping of adjacent bony structures, with dumbbell-shaped configuration. Surgical biopsy of the mass was consistent with fibroblastic meningioma. CONCLUSIONS: The reported tumor might have developed secondary to irradiation for urinary bladder cancer because meningiomas are the most common radiation-induced central nervous system tumors. Although location at the level of the conus medullaris is atypical for meningioma, and dumbbell-shaped configuration is rather characteristic for neurogenic tumors, they should not exclude a diagnosis of meningioma.

The traumatic brain injury: diagnosis and management at emergency department by general surgeon. A retrospective critical analysis on the use of the CT head scan.

AIM: In recent decades, considerable progress has been made in diagnosis and management of cranial trauma patients. Computed Tomography has resulted in a revolution in head injury diagnosis, making it possible to detect cases suitable for surgical treatment in a rapid, non-invasive manner. We present our experience in treating patients with head injuries at Emergency Department by describing the process and the criteria under which any diagnostic test is performed focusing in CT head scan. MATERIAL AND METHODS: Between 2007-2009 we studied 1356 adult patients (725 male and 631 female) who came at the emergency department claiming head injury. The factors registered were the mechanism of injury, the neurological evaluation, the Glasgow Coma Scale (GCS), the specialty of the doctor who made the first evaluation, and finally in which cases and with which criteria the CT scan was performed. RESULTS: Only a disproportionate small number of the patients who arrive at the emergency room claiming head injury require neurosurgical intervention (4.8% in our study). The majority of the CT scans who are performed as emergency procedure have no pathological findings (53.4%). CONCLUSION: The general surgeon with the appropriate education is able to evaluate the patients with head injury.

HRCT findings in the lungs of non-smokers with neurofibromatosis.

PURPOSE: Interstitial lung disease in neurofibromatosis (NF) has been disputed and attributed to smoking-related changes. The aim of this study was to describe HRCT findings in the lungs of non-smokers with NF. MATERIALS AND METHODS: Six never-smokers with NF underwent lung HRCT. Two radiologists evaluated the HRCT scans and a final decision was reached by consensus. The HRCT scans were analyzed with regard to the number, size, location (upper, middle or lower lung zone) and distribution (peripheral and central) of lung cysts and the presence of ground-glass density centrilobular micronodules. RESULTS: All patients with NF had small (2-18 mm) thin wall cysts and upper-lobe predominant patchy areas of ground-glass density centrilobular micronodules. In five cases, there were 3-17 cysts and in one there were numerous (>100). Lung cysts were central (1), subpleural (1) and in both locations (4). CONCLUSION: Interstitial lung disease in NF is not associated with smoking and may be entirely asymptomatic. HRCT may reveal small cysts, with barely perceptible walls therefore not representing emphysema and occasionally a minimal micronodular pattern of ground glass opacity. There was no radiologic evidence of lung fibrosis, honeycombing or severe bullous disease.

Subclavian steal syndrome secondary to Takayasu arteritis in a young female Caucasian patient.

Subclavian steal syndrome (SSS) is most frequently described in Caucasians aged over 50 years because of increased incidence of atherosclerosis in this population. Non-atherosclerotic etiologies of SSS are rare in Caucasians. We present a case of Subclavian Steal Syndrome secondary to Takayasu Arteritis (TA) in a 26 year-old female Caucasian patient. The present case underscores that despite the very low incidence of TA in Caucasians (0.8/1,000,000), this large-vessel vasculitis of unknown etiology should always be considered in the differential diagnosis of subclavian steal syndrome in Caucasian women aged less than 40 years.

Spontaneous bowel perforation complicating ventriculoperitoneal shunt: a case report.

Ventriculoperitoneal shunt placement is an effective treatment of hydrocephalus diverting the cerebrospinal fluid into the peritoneal cavity. Unfortunately, the shunt devices have a high incidence of malfunction mainly due to catheter obstruction or infection and are associated with various complications, 25% of which are abdominal. Spontaneous bowel perforation is a rare potentially fatal complication of ventriculoperitoneal shunt occurring anytime, few weeks to several years, after the placement of the ventriculoperitoneal shunt device. A 54-year-old Greek man with spontaneous perforation of sigmoid colon as a complication of distal ventriculoperitoneal shunt migration was treated successfully by antibiotic prophylaxis and abdominal surgery. Clinicians managing patients with ventriculoperitoneal shunt must be familiar with its possible complications and be aware for early recognition of them.