Multiple intracranial schwannomas of the vestibular and trigeminal nerves: Technical note

BACKGROUND

A schwannoma is a nerve sheath tumor that is formed by Schwann cells. Vestibular schwannomas are thought to account for the majority of intracranial schwannomas. Non-vestibular schwannomas account for about 10%, about half of which are trigeminal schwannomas. Multiple intracranial schwannomas originating from different cranial nerves are extremely rare.

OBSERVATION(S)

We describe the clinical case of a 42-year-old female patient with vestibular schwannoma and multiple trigeminal schwannomas. That case shows how multiple trigeminal schwannomas were identified intraoperatively during elective surgery for vestibular schwannoma removal, most of which were resected. No new neurological deficits were observed in the patient.

LESSONS

The presence of multiple intracranial schwannomas is extremely rare in neurosurgical practice and can change the intraoperative strategy and the course of the surgery.

Surgical corridor formation by minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach in pineal region tumor surgery: A review of 11 cases

INTRODUCTION

The pineal region is a hard-to-reach part of the brain. There is no unequivocal opinion on the choice of a surgical approach to the pineal region. The surgical approaches described differ in both trajectory (infra- and supratentorial, interhemispheric) and size of craniotomy. They have advantages and disadvantages. The minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach we have described has all the advantages of the standard supratentorial approach and minimizes its disadvantages, namely, compression and contusion of the occipital lobe. The minimally invasive craniotomy and small surgical corridor facilitate that.

METHODS

We describe 11 consecutive patients with various pineal region tumors (7 cases of pineal cysts, 2 cases of pinealocytoma, 1 case of medulloblastoma, and 1 case of meningioma) who were operated on in our hospital using the lateral OICST approach. Preoperative planning was performed using Surgical Theater®. The surgical corridor was formed using a retractor made from half of a syringe shortened according to the length of the surgical corridor. Preoperative lumbar drain was used.

RESULTS

The pineal region tumors were completely resected in all cases. The mean craniotomy size was 2.22 × 1.79 cm. No long-term neurological deficits were reported.

CONCLUSIONS

The use of semicircular retractors and intraoperative CSF drainage via a lumbar drain allows to form a small surgical corridor to the pineal region via minimally invasive craniotomy. This reduces traction and traumatization of the occipital lobe, as well as minimizes intra- and postoperative risks.

Fully endoscopic posterior fossa decompression for Chiari malformation type I: illustrative case

BACKGROUND

Surgery for symptomatic Arnold-Chiari malformation type I involves posterior fossa decompression. There are various approaches, including endoscope-assisted ones. New possibilities and fields of application of fully endoscopic techniques are currently being developed since new and advanced endoscopic equipment and instrumentation are available.

OBSERVATIONS

The authors describe the case of a fully endoscopic microsurgical procedure in a 30-year-old female patient with progressive vertigo who was diagnosed with Chiari malformation type I. Neuronavigation and neuromonitoring were used during the surgery.

LESSONS

Fully endoscopic surgery can be successfully performed in patients with Chiari malformation I. Intraoperative neuromonitoring and neuronavigation increase safety during this procedure.

Propionibacterium acnes: A Difficult-to-Diagnose Ventriculoperitoneal Shunt Infection. Case Report

BACKGROUND

 Ventriculoperitoneal (VP) shunt infections are a fairly common complication in both the early and late postoperative periods. Sometimes diagnosis is difficult despite the fact that infection is often accompanied by clinical symptoms. Furthermore, pathogenic bacteria can be detected in the cerebrospinal fluid.

METHOD

 We describe a case of chronic VP shunt infection in a 24-year-old female patient who was operated on for posterior fossa pilocytic astrocytoma and needed a VP shunt. The infection revealed itself 5 years after shunt implantation with nonspecific symptoms, and it took approximately 2 years to make a correct diagnosis. Meanwhile, the patient's condition became critical. The infection was caused by Propionibacterium acnes, which is capable of forming biofilms on implants, and which is difficult to identify due to the peculiarity of its cultivation.

RESULT

 When the bacterium was identified, the shunt was replaced and antimicrobial therapy was performed, after which the patient's condition improved dramatically and she got back to her normal life.

CONCLUSIONS

 This case shows how difficult the diagnosis of VP shunt infection can be and what clinical significance it can have for the patient.

The Brainstem Cavernoma Case Series: A Formula for Surgery and Surgical Technique

Background and Objectives: Cavernous malformations (CM) are vascular malformations with low blood flow. The removal of brainstem CMs (BS) is associated with high surgical morbidity, and there is no general consensus on when to treat deep-seated BS CMs. The aim of this study is to compare the surgical outcomes of a series of deep-seated BS CMs with the surgical outcomes of a series of superficially located BS CMs operated on at the Department of Neurosurgery, College of Tuebingen, Germany. Materials and Methods: A retrospective evaluation was performed using patient charts, surgical video recordings, and outpatient examinations. Factors were identified in which surgical intervention was performed in cases of BS CMs. Preoperative radiological examinations included MRI and diffusion tensor imaging (DTI). For deep-seated BS CMs, a voxel-based 3D neuronavigation system and electrophysiological mapping of the brainstem surface were used. Results: A total of 34 consecutive patients with primary superficial (n = 20/58.8%) and deep-seated (n = 14/41.2%) brainstem cavernomas (BS CM) were enrolled in this comparative study. Complete removal was achieved in 31 patients (91.2%). Deep-seated BS CMs: The mean diameter was 14.7 mm (range: 8.3 to 27.7 mm). All but one of these lesions were completely removed. The median follow-up time was 5.8 years. Two patients (5.9%) developed new neurologic deficits after surgery. Superficial BS CMs: The median diameter was 14.9 mm (range: 7.2 to 27.3 mm). All but two of the superficial BS CMs could be completely removed. New permanent neurologic deficits were observed in two patients (5.9%) after surgery. The median follow-up time in this group was 3.6 years. Conclusions: The treatment of BS CMs remains complex. However, the results of this study demonstrate that with less invasive posterior fossa approaches, brainstem mapping, and neuronavigation combined with the use of a blunt "spinal cord" dissection technique, deep-seated BS CMs can be completely removed in selected cases, with good functional outcomes comparable to those of superficial BS CM.

Minimally Invasive Dorsal Approach for the Treatment of Giant Presacral Schwannomas

BACKGROUND

The treatment of giant presacral schwannomas is currently a grand challenge for neurosurgeons. Although these tumors are benign and do not infiltrate the surrounding tissues, it is difficult to choose the best surgical approach because they are surrounded by the pelvic organs and great vessels. There is no universally accepted approach to the surgical treatment because giant presacral schwannomas are rare in the population. The anterior approach through laparotomy is more often recommended in the literature. A dorsal approach that involves laminotomy and stabilization is also described in the literature. However, these approaches are rather traumatic for the patient and have both intraoperative and postoperative risks.

OBJECTIVE

To report a minimally invasive dorsal approach for the treatment of giant presacral schwannomas.

METHODS

We present a fundamentally new approach to the treatment of these tumors using a minimally invasive dorsal approach, based on the specific anatomy and growth of giant presacral schwannomas. This approach is using the potential of modern neurosurgery.

RESULTS

We describe 2 cases of successful total tumor resection using this novel surgical approach. No complications have been registered after the surgery.

CONCLUSION

A minimally invasive dorsal approach for the treatment of giant presacral schwannomas is sufficient for complete tumor removal, minimizes intraoperative and postoperative risks, is associated with good cosmetic effect, and can be successfully applied in surgical practice.

The Minimally Invasive Lateral Occipital Infracortical Supra-/Transtentorial Approach in Surgery of Lesions of the Pineal Region: A Possible Alternative to the Standard Approaches

OBJECTIVE

The pineal region is an anatomical region that is difficult to access surgically, especially when it comes to removing neoplasms. Four main surgical approaches to this region are used as standards nowadays: infratentorial supracerebellar, occipital supra-/transtentorial, interhemispheric, and transventricular approaches. All methods have both advantages and disadvantages and are associated to any extent with intra- and postoperative risks. We have developed a lateral minimally invasive occipital infracortical supra-/transtentorial (OICST) approach, which retains the advantages of the standard occipital transtentorial approach while improving tumor exposure and minimizing its disadvantages.

METHODS

We describe 7 consecutive cases of successful complete removals of pineal tumor formations of various quality and size (3 pineal cysts, 2 pineocytomas, 1 meningioma, 1 medulloblastoma) using the OICST approach developed by us. Preoperative 3-dimensional and virtual reality-modeling and the use of a special retractor also contributed to reducing the size of the surgical approach.

RESULTS

All patients underwent surgery for removal of a lesion in the pineal region and suffered from no new and permanent neurological deficits postoperatively. The mean size of the craniotomies was 2.3 × 1.85 cm. The minimally invasive approach developed by us carries the advantages of the standard occipital transtentorial approach, but minimizes its disadvantages. The main disadvantage of the standard occipital approach is excessive retraction of the occipital lobe, which is frequently associated with visual neurological deficits. Also, with occipital approach, the Rosenthal vein lying along the surgical corridor is frequently not good visible since the tumor is approached from its tip rather than side which limits the overview of the surgical field and can pose a risk. Damage to this vein can cause infarction of the basal ganglia. By approaching the pineal region from more laterally the size of the craniotomy can significantly be reduced, excessive retraction of the occipital lobe can be avoided and the risk of damage to large deep veins can be minimized. The cosmetic outcome with a small skin incision of only about 3 cm is also a very good side effect of this minimally invasive technique.

CONCLUSIONS

The minimally invasive lateral OICST approach described by us can be successfully used in the surgery of pineal neoplasms. Reducing the size of the craniotomy does not limit the possibility of complete removal of tumors of various sizes and tissue consistency, and also minimizes the risks of both intra- and postoperative complications.

Minimally invasive dorsal approach in the surgery of giant thoracic disc herniation: technical note and clinical case report

Giant thoracic disc herniations are calcified hernias that fill more than 40% of the spinal canal and result in myelopathy with associated neurological symptoms. This is a fairly rare abnormality that requires surgical treatment. Currently, there is no unambiguous opinion about the surgical approach to the treatment this pathology. It is believed that the most effective method is the anterior approach (mini-thoracotomy or thoracoscopic approach), which reduces the risks of spinal cord injury, but is associated with the risks of damage to the lungs, pleura and major vessels. It is also quite large. We describe the case of a 60-year-old female patient with a giant thoracic disc herniation. Complete removal of the hernia through a minimally invasive dorsal approach was performed, followed by stabilization. No complications have been registered after the surgery. In this case, surgery resulted in a curative treatment outcome for the patient.

Total resection of presacral giant schwannoma via minimally invasive dorsal approach: illustrative case

BACKGROUND

Giant presacral schwannomas are extremely rare in neurosurgery. There are various approaches to the surgical treatment of symptomatic giant presacral schwannomas. The least traumatic is the one-stage surgery with a dorsal approach.

OBSERVATIONS

The authors describe a case of a 52-year-old male with pain in the sacral region and partial urinary dysfunction. A total tumor resection through a minimally invasive dorsal approach was performed, and anatomical and functional preservation of all sacral nerves with no postoperative complications was achieved.

LESSONS

The authors have shown the possibility of total tumor resection with a minimally invasive dorsal approach without the development of intra- and postoperative complications. Operative corridors that have been created by a tumor can be used and expanded for a minimally invasive dorsal approach to facilitate resection and minimize tissue disruption.

[Lumbar CT-guided radiofrequency ablation of the medial branch of the dorsal ramus of the spinal nerve : Anatomic study and description of a new technique]

BACKGROUND

The success of radiofrequency ablation (RF) of the medial branch of the dorsal ramus in patients with facet joint pain depends on the effective coagulation distance. To date, computed tomography(CT)-guided techniques do not reach the nerve in parallel but rather than punctually. We report a new CT-guided technique to enhance parallelism and proximity of the RF needle to the nerve.

MATERIALS AND METHODS

Two examiners with different experience with CT-guided procedures in corpses performed all punctures at the lumbar spine on 10 corpses. A RF needle was inserted 1 cm lateral to the spinous process of the vertebra located caudal to the target nerve. The needle was advanced under CT guidance at a flat angle between the superior articular process and the base of the costal or transverse process of the cranial vertebra. The position was verified by dissection. Needle position was judged successful provided the needle could be positioned in the first attempt with no more than one angle correction.

RESULTS

In 86 out of 100 possible cases (50 per side) at the 5 lumbar segments, the RF needle could be depicted by CT in the target area with no more than one correction of the needle position. Anatomical dissections revealed that 47 out of 86 needles (54.6%) fulfilled the requirements of parallelism and proximity to the nerve. The dorsal ramus was never reached by the RF needle. Higher success rates were obtained in the middle segments compared to the border segments of L1-L2 and L5-S1.

CONCLUSIONS

We could demonstrate that the principle of parallelism and proximity of the needle to the nerve could be fulfilled with this new technique; however, needle positioning requires practice due to the oblique puncture direction.

Feasibility and accuracy of a voxel-based neuronavigation system with 3D image rendering in preoperative planning and as a learning tool for young neurosurgeons, exemplified by the anatomical localization of the superior sagittal sinus

It is essential for a neurosurgeon to know individual anatomy and the corresponding anatomical landmarks before starting a surgery. Continuous training, especially of young neurosurgeons, is crucial for understanding complex neuroanatomy. In this study, we used a neuronavigation system with 3D volumetric image rendering to determine the anatomical relationship between the sagittal suture and the superior sagittal sinus (SSS) in patients with intracranial lesions. Furthermore, we discussed the applicability of such system in preoperative planning, residency training, and research. The study included 30 adult patients (18 female/12 male) who underwent a cranial computed tomography (CT) scan combined with venous angiography, for preoperative planning. The position of the sagittal suture in relation to the SSS was assessed in 3D CT images using an image guidance system (IGS) with 3D volumetric image rendering. Measurements were performed along the course of the sagittal sinus at the bregma, lambda, and in the middle between these two points. The SSS deviated to the right side of the sagittal suture in 50% of cases at the bregma, and in 46.7% at the midpoint and lambda. The SSS was displaced to the left of the sagittal suture in 10% of cases at the bregma and lambda and in 13% at the midpoint. IGSs with 3D volumetric image rendering enable simultaneous visualization of bony surfaces, soft tissue and vascular structures and interactive modulation of tissue transparency. They can be used in preoperative planning and intraoperative guidance to validate external landmarks and to determine anatomical relationships. In addition, 3D IGSs can be utilized for training of surgical residents and for research in anatomy.

Review of first clinical experiences with a 1.5 Tesla ceiling-mounted moveable intraoperative MRI system in Europe

High-field intraoperative MRI (iMRI) systems provide excellent imaging quality and are used for resection control and update of image guidance systems in a number of centers. A ceiling-mounted intraoperative MRI system has several advantages compared to a conventional iMRI system. In this article, we report on first clinical experience with using such a state-of-the-art, the 1.5T iMRI system, in Europe. A total of 50 consecutive patients with intracranial tumors and vascular lesions were operated in the iMRI unit. We analyzed the patients' data, surgery preparation times, intraoperative scans, surgical time, and radicality of tumor removal. Patients' mean age was 46 years (range 8 to 77 years) and the median surgical procedure time was 5 hours (range 1 to 11 hours). The lesions included 6 low-grade gliomas, 8 grade III astrocytomas, 10 glioblastomas, 7 metastases, 7 pituitary adenomas, 2 cavernomas, 2 lymphomas, 1 cortical dysplasia, 3 aneurysms, 1 arterio-venous malformation and 1 extracranial-intracranial bypass, 1 clival chordoma, and 1 Chiari malformation. In the surgical treatment of tumor lesions, intraoperative imaging depicted tumor remnant in 29.7% of the cases, which led to a change in the intraoperative strategy. The mobile 1.5T iMRI system proved to be safe and allowed an optimal workflow in the iMRI unit. Due to the fact that the MRI scanner is moved into the operating room only for imaging, the working environment is comparable to a regular operating room.

Thermocoagulation of the Medial Branch of the Dorsal Branch of the Lumbal Spinal Nerve: Flouroscopy Versus CT

Objective

For radiofrequency neurotomy of the medial branch of the lumbar dorsal rami, physicians use techniques guided either by fluoroscopy or computerized tomography (CT), and advocate for their respective techniques. Crucial to the choice of technique is how well each can capture the target nerve. The present study was, therefore, undertaken to assess in cadavers the accuracy of fluoroscopic-guided and CT-guided techniques.

Design

In10 cadavers preserved with Thiel's method, electrodes with 10mm active tips were placed in supine position on the right using a fluoroscopic-guided technique, and on the left using a CT-guided technique. Using a special dissection approach, the relationship between the target nerve and the tip of the electrode was revealed. The displacement between electrode and the nerve, and the extent to which the electrode was parallel to the nerve, were measured with callipers.

Results

Under fluoroscopy guidance, electrodes were placed accurately beside the nerve, and were parallel to it for 9 ±1.9 mm. In only two cases did the electrode pass too deeply. Under CT guidance, electrodes often failed to reach the nerve, but when they did they were parallel to it for only 3.2 ± 3.2 mm. In seven cases, the electrode passed too deeply beyond the target nerve.

Conclusion

The fluoroscopy-guided technique can be relied upon to achieve optimal placement of electrodes on the lumbar medial branches. The CT-guided technique fails to do so, and should not be used in practice until a modified version has been developed and validated.

Experiences in surgery of primary malignant brain tumours in the primary sensori-motor cortex practical recommendations and results of a single institution

OBJECTIVE

Tumour resection in the Rolandic region is a challenge. Aim of this study is to review a series of patients malignant glioma surgery in the Rolandic region which was performed by combinations of neuronavigation, sonography, 5-aminolevulinic acid fluorescence guided (5-ALA) surgery and intraoperative electrophysiological monitoring (IOM).

METHODS

29 patients suffering malignant gliomas in the motor cortex (17) and sensory cortex (12) were analyzed with respect to functional outcome and grade of resections.

RESULTS

Improvement of motor function was seen in 41.5% one week after surgery, 41.5% were stable, only 17% deteriorated. After three months patients had an improvement of motor function in 56%, of Karnofsky Score (KPS) 27% and sensory function was improved in 8%. Deterioration of motor function was seen in 16%, in sensory function 4% and in KPS 28% after three months. 25% showed no residual tumour in early post surgical contrast enhanced MRI. 10% had less than 2% residual tumour and 15% had 2-5% residual tumour.

CONCLUSIONS

Preoperative functional neuroimaging, neuronavigation for planning the surgical approach and resection margins, intraoperative sonography and 5-ALA guided surgery in combination with the application of IOM shows that functional outcome and total to subtotal resection of malignant glioma in the Rolandic region is feasible.

Male sex as a risk factor for the clinical course of skull base chordomas

Object

Chordomas of the skull base are rare and locally invasive and have a poor prognosis. The aim of this retrospective multicenter study was to evaluate the current pattern of care and clinical course and to identify prognostic factors.

Methods

A total of 47 patients (26 men; mean age 48.5 years) treated in 5 centers were included. Histology was centrally reviewed; additionally, semiquantitative N- and E-cadherin expression analysis was performed. Prognostic factors were obtained from multivariate regression models. For survival analysis the Kaplan-Meier method was used.

Results

The median follow-up period was 5.2 years. Complete resection, incomplete resection, and extended biopsy were performed in 14.9%, 80.9%, and 4.3% of patients, respectively. Surgical morbidity was not associated with extent of resection. Adjuvant radiation therapy was performed in 30 (63.8%) of 47 patients. The median progression-free survival (PFS) was 7.3 years. Complete resection prolonged median overall survival (OS) (p = 0.04). Male patients presented with worse PFS (4.8 years vs 9.8 years; p = 0.04) and OS (8.3 years vs not reached; p = 0.03) even though complete resection was exclusively achieved in the male subpopulation. Multivariate analysis confirmed male sex as the most important risk factor for tumor progression (p = 0.04) and death (p = 0.02). Age, duration of symptoms, initial Karnofsky Performance Scale score, brainstem compression, involvement of the petrous bone, infiltration of the dura mater, modality and dose of radiation therapy, and the E- and N-cadherin expression patterns did not gain prognostic relevance.

Conclusions

In skull base chordomas, male patients bear a higher risk of progressive disease and death. Male patients might benefit from more aggressive adjuvant therapy and/or from a closer follow-up schedule.

Patient response to awake craniotomy - a summary overview

BACKGROUND

Awake craniotomy is a valuable procedure since it allows brain mapping and live monitoring of eloquent brain functions. The advantage of minimizing resource utilization is also emphasized by some physicians in North America. Data on how well an awake craniotomy is tolerated by patients and how much stress it creates is available from different studies, but this topic has not consequently been summarized in a review of the available literature. Therefore, it is the purpose of this review to shed more light on the still controversially discussed aspect of an awake craniotomy.

METHODS

We reviewed the available English literature published until December 2013 searching for studies that investigated patients' responses to awake craniotomies.

RESULTS

Twelve studies, published between 1998 and 2013, including 396 patients with awake surgery were identified. Eleven of these 12 studies set the focus on the perioperative time, one study focused on the later postoperative time. The vast majority of patients felt well prepared and overall satisfaction with the procedure was high. In the majority of studies up to 30 % of the patients recalled considerable pain and 10-14 % experienced strong anxiety during the procedure. The majority of patients reported that they would undergo an awake craniotomy again. A post traumatic stress disorder was present neither shortly nor years after surgery. However, a normal human response to such an exceptional situation can for instance be the delayed appearance of unintentional distressing recollections of the event despite the patients' satisfaction concerning the procedure.

CONCLUSIONS

For selected patients, an awake craniotomy presents the best possible way to reduce the risk of surgery related neurological deficits. However, benefits and burdens of this type of procedure should be carefully considered when planning an awake craniotomy and the decision should serve the interests of the patient.

Primary cerebral low-grade B-cell lymphoma, monoclonal immunoglobulin deposition disease, cerebral light chain deposition disease and "aggregoma": an update on classification and diagnosis

Background

This work aims to add evidence and provide an update on the classification and diagnosis of monoclonal immunoglobulin deposition disease (MIDD) and primary central nervous system low-grade lymphomas. MIDD is characterized by the deposition of light and heavy chain proteins. Depending on the spatial arrangement of the secreted proteins, light chain-derived amyloidosis (AL) can be distinguished from non-amyloid light chain deposition disease (LCDD). We present a case of an extremely rare tumoral presentation of LCDD (aggregoma) and review the 3 previously published LCDD cases and discuss their presentation with respect to AL.

Case presentation

A 61-year-old woman presented with a 3½-year history of neurologic symptoms due to a progressive white matter lesion of the left subcortical parieto-insular lobe and basal ganglia. 2 former stereotactic biopsies conducted at different hospitals revealed no evidence of malignancy or inflammation; thus, no therapy had been initiated. After performing physiological and functional magnetic resonance imaging (MRI), the tumor was removed under intraoperative monitoring at our department. Histological analysis revealed large amorphous deposits and small islands of lymphoid cells.

Conclusion

LCCD is a very rare and obscure manifestation of primary central nervous system low-grade lymphomas that can be easily misdiagnosed by stereotactic biopsy sampling. If stereotactic biopsy does not reveal a definite result, a “wait-and-see” strategy can delay possible therapy for this disease. The impact of surgical removal, radiotherapy and chemotherapy in LCDD obviously remains controversial because of the low number of relevant cases.

“Imagine your neighbor mows the lawn”: a pilot study of psychological sequelae due to awake craniotomy

Object

Although it has been reported that awake neurosurgical procedures are well tolerated, the long-term occurrence of general psychological sequelae has not yet been investigated. This study assessed the frequency and effects of psychological symptoms after an awake craniotomy on health-related quality of life (HRQOL).

Methods

Sixteen patients undergoing an awake surgery were surveyed with a self-developed questionnaire, the Posttraumatic Stress Disorder Inventory For Awake Surgery Patients, which adopts the core components of the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) posttraumatic stress disorder (PTSD) criteria. The mean time between surgery and data collection was 97.3 ± 93.2 weeks. Health-related quality of life was assessed with the 36-Item Short Form Health Survey.

Results

Forty-four percent of the patients stated that they had experienced either repetitive distressing recollections or dreams related to the awake surgery, 18.8% stated persistent avoidance of stimuli associated with the awake surgery, and symptoms of increased arousal occurred in 62.5%. Two patients presented with postoperative psychological sequelae resembling PTSD symptoms. Younger age at surgery and female sex were risk factors for symptoms of increased arousal. The experience of intense anxiety during awake surgery appears to favor the development of postsurgical PTSD symptoms, while recurrent distressing recollections particularly affect HRQOL negatively.

Conclusions

In many cases awake craniotomy is necessary to preserve language and motor function. However, in some cases awake craniotomy can lead to postoperative psychological sequelae resembling PTSD symptoms. Therefore, possible long-term effects of an awake surgery should be considered and discussed with the patient when planning this type of surgery.

Neurosurgical procedures in the semisitting position: evaluation of the risk of paradoxical venous air embolism in patients with a patent foramen ovale

OBJECTIVE

To analyze the actual risk for patients with a patent foramen ovale (PFO) to experience a clinically relevant venous air embolism (VAE) during surgery performed in the semisitting position.

METHODS

All procedures were performed between January 2008 and December 2009, under general anesthesia and in the semisitting position. Transesophageal echocardiography (TEE) and capnometry were used intraoperatively to monitor for air bubbles in the venous system.

RESULTS

Of 200 consecutive patients who all were operated on in the semisitting position, 52 patients (26%) had a diagnosis of PFO. Rates of VAE in patients were graded as follows: grade 0 (no air bubbles visible, no air embolism), 23 patients (44.2%); grade I (air bubbles on TEE), 22 patients (42.3%); grade II (air bubbles on TEE with decrease of end-tidal carbon dioxide [ETCO2] ≤ 3 mm Hg), 2 patients (3.8%); grade III, air bubbles on TEE with decrease of ETCO2 >3 mm Hg, 4 patients (7.7%); grade IV, air bubbles on TEE with decrease of ETCO2 >3 mm Hg and decrease of mean arterial pressure ≥ 20% or increase of heart rate ≥ 40% (or both), 1 patient (1.9%); and grade V, VAE causing arrhythmia with hemodynamic instability requiring cardiopulmonary resuscitation, 0 patients (0%). There were no deaths in this series, and no new or unexplained, mild or severe neurologic deficits were caused by a VAE.

CONCLUSIONS

Under standardized anesthesia and neurosurgical protocols, patients with a PFO can be operated on safely in the semisitting position.

Hypericin for visualization of high grade gliomas: first clinical experience

AIMS

We aimed to demonstrate that Hypericin, a component of St. Johns Wort, selectively visualizes malignant gliomas. Hypericin is known as one of the most powerful photosensitizers in nature with excellent fluorescent properties.

METHODS

In five patients with a recurrence of a malignant glioma a newly developed water soluble formulation of hypericin was given intravenously (0.1 mg/kg body weight) 6 h before the surgical procedure. Tumor resection was performed under white light and fluorescence mode. The intensity grade of the tissue fluorescence was categorisized by the surgeon in three grades, highly fluorescent, weakly fluorescent and not fluorescent. In these areas tissue samples were taken and investigated by two blinded independent neuropathologists. Tissue samples were histologically classified differentiating between tumor tissue, tumor necrosis, tissue with scattered tumor cells and normal brain tissue.

RESULTS

In all patients tumor tissue was clearly distinguishable by its typically red fluorescence color from normal brain tissue which was colored blue under a special fluorescent filter. Histological evaluation of the 110 tissue samples showed a specificity of 100% and sensitivity of 91% for one of the two neuropathologists, whereas specificity for second pathologist was 90% and sensitivity 94%. The i.v. application of Hypericin proofed to be safe in all cases and there were no side effects observed.

CONCLUSION

Hypericin in its water soluble form is a well tolerated drug. In addition to its high photosensitizing properties hypericin will open up interesting new therapeutic possibilities especially when used in combination with fluorescence detection and simultaneously photodynamic therapy.

Levetiracetam compared to phenytoin for the prevention of postoperative seizures after craniotomy for intracranial tumours in patients without epilepsy

Anticonvulsant drugs are frequently given after craniotomy. Phenytoin (PHT) is the most commonly used agent; levetiracetam (LEV) is a new anticonvulsant drug with fewer side effects. To compare the incidence of seizures in patients receiving either prophylactic PHT or LEV perioperatively, 971 patients undergoing a craniotomy were analysed retrospectively during a 2-year period. PHT was used routinely and LEV was administered when PHT was contraindicated. Seizures documented during the first 7 days after craniotomy were considered. A total of 235 patients were treated with an antiepileptic drug: 81 patients received LEV, and 154 patients, PHT. Two patients receiving LEV (2.5%) and seven receiving PHT (4.5%) had a seizure despite this treatment. No patient had a documented side effect or drug interaction. The data show that LEV may be an alternative option in patients with contraindications to PHT.

Posterior cranial fossa gangliogliomas

Ganglioglioma (GG) is an uncommon primary lesion of the central nervous system that is typically located supratentorially. There are only a few reports of GG arising from the cerebellum. To the best of our knowledge this is the first case of a cerebellar GG with supratentorial extension and a longstanding history before its recognition. In fact, this 29-year-old male presented with an 11-year history of intermittent headaches. A cranial computerized tomography (CT) performed at the onset of his complaints failed to reveal the tumor. After a particularly longstanding cephalalgic episode, the patient underwent a new CT scan that was also negative. However, magnetic resonance (MR) imaging of the brain revealed a space-occupying lesion in the right cerebellar hemisphere with extension to the level of the superior colliculi and pineal recess. The tumor was partially removed through a midline suboccipital craniotomy and supracerebellar approach. Pathological examination of the tumor showed composition of atypical ganglion cells and astrocytes, indicating the diagnosis of cerebellar GG. At last follow-up, 24 months after surgery, the patient reported a marked improvement of his clinical condition with significant reduction of intensity and frequency of the headache. The present report illustrates how cerebellar GG may remain undetectable by CT and may therefore present with a longstanding history and nonspecific signs and symptoms. MR investigation can lead to the proper diagnosis. Even after partial removal the prognosis remains good and remission of the symptoms may be achieved. In this article, we review the literature and summarize the current understanding of infratentorial GGs.

Thrombophilia Due to Factor V and Factor II Mutations and Formation of a Dural Arteriovenous Fistula: Case Report and Review of a Rare Entity

Genetic mutations underlying thrombophilia are often recognized in patients with thromboembolic episodes. However, the clinical and therapeutic implications of such findings often remain unclear. We report the first case of a dural arteriovenous fistula (DAVF) in a patient with a combined factor II and factor V Leiden mutation. A 40-year-old man presented with a large left temporal and intraventricular hemorrhage. An initial angiogram showed thrombosis of the left sigmoid sinus but no evidence of a vascular malformation. One year after the hemorrhage, an angiographic study showed the appearance of a right DAVF. During the follow-up period, the patient was found to harbor heterozygosity for a mutation of factor V and a mutation of factor II. Recognition of the patient's thrombophilia led to prolonged oral anticoagulation therapy to reduce the risk of a recurrent thrombotic episode. Despite the increased risk of bleeding, the therapy was considered justified. DAVFs may occur after sinus thrombosis in patients with combined factor II and factor V mutations. This observation indicates the association of multiple hematological disorders with DAVFs in individual patients. Moreover, it raises the clinical conundrum of how to manage patients with thrombophilia, intracranial hemorrhage, and DAVFs.

Use of 5-ALA fluorescence guided endoscopic biopsy of a deep-seated primary malignant brain tumor

The introduction of fluorescence-guided resection of primary malignant brain tumors was a milestone in neurosurgery. Deep-seated malignant brain tumors are often not approachable for microsurgical resection. For diagnosis and therapy, new strategies are recommended. The combination of endoscopy and 5-aminolevulinic acid–induced protoporphyrin IX (5-ALA-induced Pp IX) fluorescence–guided procedures supported by neuronavigation seems an interesting option. Here the authors report on a combined approach for 5-ALA fluorescence–guided biopsy in which they use an endoscopy system based on an Xe lamp (excitation approximately λ = 407 nm; dichroic filter system λ = 380–430 nm) to treat a malignant tumor of the thalamus and perform a ventriculostomy and septostomy. The excitation filter and emission filter are adapted to ensure that the remaining visible blue remission is sufficient to superimpose on or suppress the excited red fluorescence of the endogenous fluorochromes. The authors report that the lesion was easily detectable in the fluorescence mode and that biopsy led to histological diagnosis.

Resection of malignant brain tumors in eloquent cortical areas: a new multimodal approach combining 5-aminolevulinic acid and intraoperative monitoring

OBJECT

Several studies have revealed that the gross-total resection (GTR) of malignant brain tumors has a significant influence on patient survival. Frequently, however, GTR cannot be achieved because the borders between healthy brain and diseased tissue are blurred in the infiltration zones of malignant brain tumors. Especially in eloquent cortical areas, resection is frequently stopped before total removal is achieved to avoid causing neurological deficits. Interestingly, 5-aminolevulinic acid (5-ALA) has been shown to help visualize tumor tissue intraoperatively and, thus, can significantly improve the possibility of achieving GTR of primary malignant brain tumors. The aim of this study was to go one step further and evaluate the utility and limitations of fluorescence-guided resections of primary malignant brain tumors in eloquent cortical areas in combination with intraoperative monitoring based on multimodal functional imaging data.

METHODS

Eighteen patients with primary malignant brain tumors in eloquent areas were included in this prospective study. Preoperative neuroradiological examinations included MR imaging with magnetization-prepared rapid gradient echo (MPRAGE), functional MR, and diffusion tensor imaging sequences to visualize functional areas and fiber tracts. Imaging data were analyzed offline, loaded into a neuronavigational system, and used intraoperatively during resections. All patients received 5-ALA 6 hours before surgery. Fluorescence-guided tumor resections were combined with intraoperative monitoring and cortical as well as subcortical stimulation to localize functional areas and fiber tracts during surgery.

RESULTS

Twenty-five procedures were performed in 18 consecutive patients. In 24% of all surgeries, resection was stopped because a functional area or cortical tract was identified in the resection area or because motor evoked potential amplitudes were reduced in an area where fluorescent tumor cells were still seen intraoperatively. Grosstotal resection could be achieved in 16 (64%) of the surgeries with preservation of all functional areas and fiber tracts. In 2 patients presurgical hemiparesis became accentuated postoperatively, and 1 of these patients also suffered from a new homonymous hemianopia following a second resection.

CONCLUSIONS

The authors' first results show that tumor resections with 5-ALA in combination with intraoperative cortical stimulation have the advantages of both methods and, thus, provide additional safety for the neurosurgeon during resections of primary malignant brain tumors in eloquent areas. Nonetheless, more cases and additional studies are necessary to further prove the advantages of this multimodal strategy.

Association of the Jun dimerization protein 2 gene with intracranial aneurysms in Japanese and Korean cohorts as compared to a Dutch cohort

In a previous study a linkage region for association to IA patients was found on chromosome 14q22. In this study, we report the findings of a positional candidate gene, Jun dimerization Protein 2 (JDP2), and single nucleotide polymorphisms (SNP) of that gene that are associated with intracranial aneurysms in different ethnic populations. We screened the linkage region around chromosome 14q22 and narrowed it down to JDP2. We then genotyped case and control groups of three different ethnic populations: 403 Japanese intracranial aneurysm (IA) cases and 412 controls, 181 Korean IA cases and 181 controls, 379 Dutch cases and 642 Dutch controls. Genotyping was performed using polymerase chain reaction and direct sequencing technology. The allele distribution of three SNPs (two intronic: rs741846; P=0.0041 and rs175646; P=0.0014, and one in the untranslated region: rs8215; P=0.019) and their genotype distribution showed significant association in the Japanese IA patients. The allelic and genotypic frequency of one intronic SNP (rs175646; P=0.0135 and P=0.0137, respectively) and the genotypic frequency for the SNP in the UTR region (rs8215; P=0.049) was also significantly different between cases and controls of the Korean cohort. There was no difference in allelic or genotypic frequencies in the Dutch population. These SNPs in JDP2 are associated with intracranial aneurysms, suggesting that variation in or near JDP2 play a role in susceptibility to IAs in East Asian populations.

Intraoperative electrical stimulation in awake craniotomy: methodological aspects of current practice

There is increasing evidence that the extent of tumor removal in low-grade glioma surgery is related to patient survival time. Thus, the goal of resecting the largest amount of tumor possible without leading to permanent neurological sequelae is a challenge for the neurosurgeon. Electrical stimulation of the brain to detect cortical and axonal areas involved in motor, language, and cognitive function and located within the tumor or along its boundaries has become an essential tool in combination with awake craniotomy. Based on a literature review, discussions within the European Low-Grade Glioma Group, and illustrative clinical experience, the authors of this paper provide an overview for neurosurgeons, neurophysiologists, linguists, and anesthesiologists as well as those new to the field about the stimulation techniques currently being used for mapping sensorimotor, language, and cognitive function in awake surgery for low-grade glioma. The paper is intended to help the understanding of these techniques and facilitate a comparison of results between users.

Real-time 3T fMRI data of brain tumour patients for intra-operative localization of primary motor areas

INTRODUCTION

In patients with tumours in or near the motor cortex reliable intra-operative identification of the precentral gyrus can be difficult due to anatomical dislocation. Maps of functional magnetic resonance imaging (fMRI) based on the blood oxygen level dependent (BOLD) effect are used to localize eloquent functional areas of the brain but require postprocessing for reduction of false positive activations. We set the focus of this study on the evaluation of feasibility and clinical usefulness of using real-time fMRI t-maps without postprocessing for pre-operative planning and intra-operative localization of functional motor areas.

METHODS

Real-time fMRI t-maps from a 3-T MRI scanner were co-registered with MRI data. Ten patients were operated under general anaesthesia using 3D neuronavigation with integrated real-time fMRI t-maps. Surgical and functional outcome was compared to results of 12 patients who previously underwent wake surgeries.

RESULTS

Good neurological outcome was achieved in all treated patients. Main activation clusters on fMRI real-time maps were easily identified. Co-registered real-time fMRI data without additional postprocessing were useful in planning the surgical approach. However, due to brain shift and large voxel size of BOLD contrast signals on t-maps exact localization of borders between tumours and functional areas was not possible intra-operatively.

CONCLUSION

Our method is very simple to use and effective in guiding the neurosurgeon safely through minimally invasive craniotomies to tumours in eloquent areas without setting lesions to functional areas. Furthermore, the neurosurgeon is more independent when tumour location requires acquisition of fMRI data for pre-operative planning and intra-operative navigation.

Predictive factors for beneficial application of high-frequency electromagnetics for tumour vaporization and coagulation in neurosurgery

Objective

To identify preoperative and intraoperative factors and conditions that predicts the beneficial application of a high-frequency electromagnetic field (EMF) system for tumor vaporization and coagulation.

Methods

One hundred three subsequent patients with brain tumors were microsurgically treated using the EMF system in addition to the standard neurosurgical instrumentarium. A multivariate analysis was performed regarding the usefulness (ineffective/useful/very helpful/essential) of the new technology for tumor vaporization and coagulation, with respect to tumor histology and location, tissue consistency and texture, patients' age and sex.

Results

The EMF system could be used effectively during tumor surgery in 83 cases with an essential contribution to the overall success in 14 cases. In the advanced category of effectiveness (very helpful/essential), there was a significant difference between hard and soft tissue consistency (50 of 66 cases vs. 3 of 37 cases). The coagulation function worked well (very helpful/essential) for surface (73 of 103 cases) and spot (46 of 103 cases) coagulation when vessels with a diameter of less than one millimeter were involved. The light-weight bayonet hand piece and long malleable electrodes made the system especially suited for the resection of deep-seated lesions (34 of 52 cases) compared to superficial tumors (19 of 50 cases).

The EMF system was less effective than traditional electrosurgical devices in reducing soft glial tumors. Standard methods where also required for coagulation of larger vessels.

Conclusion

It is possible to identify factors and conditions that predict a beneficial application of high-frequency electromagnetics for tumor vaporization and coagulation. This allows focusing the use of this technology on selective indications.

Surgical planning for retrosigmoid craniotomies improved by 3D computed tomography venography

OBJECTIVE

It is impossible to precisely anticipate the crooked course of the transverse and sigmoid sinuses and their individual relationship to superficial landmarks such as the asterion during retrosigmoid approaches. This study was designed to evaluate this anatomical relationship with the help of a surgical planning system and to analyze the impact of these in vivo findings on trepanation placement in retrosigmoid craniotomies.

METHODS

In a consecutive series of 123 patients with pathologies located in the cerebellopontine angle, 72 patients underwent surgical planning for retrosigmoid craniotomies based on 3D volumetric renderings of computed tomography venography. By opacity modulation of surfaces in 3D images the position of the asterion was assessed in relationship to the transverse-sigmoid sinus transition (TST) and compared to its intraoperative localization. We evaluated the impact of this additional information on trepanation placement.

RESULTS

The spatial relationship of the asterion and the underlying TST complex could be identified and recorded in 66 out of 72 cases. In the remaining 6 cases the sutures were ossified and not visible in the 3D CT reconstructions. The asterion was located on top of the TST in 51 cases, above the TST in 4 cases, and below the TST in 11 cases. The location of the trepanation was modified in 27 cases due to the preoperative imaging findings with major and minor modifications in 10 and 17 cases, respectively.

CONCLUSION

Volume-rendered images provide reliable 3D visualization of complex and hidden anatomical structures in the posterior fossa and thereby increase the precision in retrosigmoid approaches.

Image-guided craniotomy for frontal sinus preservation during meningioma surgery

OBJECTIVE

Preservation of the frontal sinus (FS) during the frontolateral approach to the skull base reduces morbidity, enhances patient comfort, and speeds up the surgical procedure. Due to its irregular outline, mental reconstruction of the borders of FS from two-dimensional images is challenging during surgery. This study was designed to evaluate the impact of neuronavigation on identification and preservation of the FS during frontolateral craniotomies.

METHODS

Forty-five patients with pathologies located in the anterior skull base and in the parasellar region were included. A standard computed tomography (CT) sequence was obtained from each patient and uploaded onto an image-guidance system for volumetric rendering of 3D images. The outline of the FS was visualized and the distance between its lateral border and the mid-pupillary line (MPL) was measured. The results were used for navigated craniotomies and compared to the intra-operative findings.

RESULTS

The FS was located medial, on and lateral to the MPL in 32, 4 and 9 cases, respectively. The individual outline of the FS could be identified with a mean target registration error of 1.4mm (+/-0.7 mm). The craniotomy could be custom-tailored for each patient according to the individualized landmarks while visualizing the lesion and the surgical landmarks simultaneously. Unintended opening of the frontal sinus or orbit did not occur in any of these cases.

CONCLUSION

Image-guided craniotomies based on 3D volumetric image rendering allow for fast and reliable demarcation of complex anatomical structures hidden from direct view in frontolateral approaches. The outline of the frontal sinus and the orbit can be appraised at a glance providing additional safety and precision during craniotomy.

VOLUMETRIC FOLLOW-UP OF MENINGIOMAS

OBJECTIVE

The most important treatment options for meningiomas are microsurgery, radiotherapy, and gamma knife radiosurgery (GKRS). The efficacy of GKRS in terms of local tumor control and tumor volume (TV) reduction can best be determined by accurate analysis of changes in tumor size in pre- and post-GKRS images. In this prospective study, we set the focus on evaluating TV changes and treatment outcome of meningiomas using a quantitative volumetric follow-up protocol after GKRS.

METHODS

Consecutive patients with World Health Organization Grade I and II meningiomas were included in this study. Most patients underwent a microsurgical TV reduction before being treated with GKRS. Follow-up examinations were performed according to a standardized protocol and included magnetic resonance imaging and quantitative volumetric tumor analyses as well as thorough neurological examinations.

RESULTS

Complete follow-up data was available for 211 patients (243 tumors) with a mean age of 57.9 years. TVs ranging from 0.1 to 48.3cm3 were treated with GKRS using prescription doses ranging from 10 to 22 Gy. The achieved overall tumor control rate determined with quantitative TV analyses after GKRS was 93.4%; a mean TV reduction of 42.1% was achieved in 74.5% of all treated patients.

CONCLUSION

Results of this study show that a quantitative volumetric follow-up study of meningiomas is a useful method to demonstrate the efficacy of GKRS for meningiomas. Statistically significant TV reductions with a low rate of side effects can be achieved with GKRS.

Applicability of an Electrosurgical Device Based on Electromagnetics in Neurosurgery

Because of electrical and thermal spread to healthy nervous tissue, the application of electrosurgical tools in neurosurgery has specific limitations. This is true for both bipolar and monopolar devices. These limitations are not inherent to an instrument in which action is based on electromagnetic interaction with human tissue. We evaluated the indications and the clinical applicability of a new radiofrequency electrosurgical unit that works on this biophysical principle. The system was found to be a useful addition for the resection of morphologically tougher tissue with keyhole approaches in which the ultrasound aspirator cannot easily be applied.

Volume reduction in meningiomas after gamma knife surgery

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.

Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.

The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.

Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

Volume reduction in meningiomas after gamma knife surgery

Object. The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.

Methods. A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.

The mean tumor volume was 5.9 cm3 (range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.

Conclusions. Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.