The auricula as a new surgical landmark for the transverse-sigmoid-sinus-transition.

Introduction: The transverse-sigmoid-sinus-transition constitutes an important landmark during a retrosigmoid craniotomy. Due to anatomical variations, the location is highly variable. Landmarks for identification of the anterior border of the sigmoid sinus have been described extensively, such as the mastoid notch, digastric point, external auditory meatus and crux of the helix curvature. There is a paucity of landmarks for the identification of the posterior border, however. Research question: We examined the relationship between the transverse-sigmoid-sinus-transition and the most-posterior-part-of-the-auricula. Material and methods: We performed a retrospective analysis of one-hundred patients (38 males and 62 females) who underwent cerebral MRI examinations at Antwerp University Hospital (Belgium). Using Brainlab®, the transverse-sigmoid-sinus-transition and most-posterior-part-of-the-auricula coordinates were calculated and compared. Left and right sides were compared in both the anteroposterior and craniocaudal axis. Results: Mean age was 56.4 ± 16.1 years. Mean MPPA-TSST-distance in the anteroposterior direction was -1.93 mm (right) and -1.96 mm (left). Mean MPPA-TSST-distance in the craniocaudal direction was -5.16 mm (right) and -5.04 mm (left). Discussion and conclusion: The transverse-sigmoid-sinus-transition seems to be located more anterior and caudal with respect to the most-posterior-part-of-the-auricula, meaning that it can be considered a save landmark. A correction of five mm needs to be applied in order to identify the inferior border of the transverse sinus. Left/right and gender had no significant influence. The most-posterior-part-of-the-auricula can be considered a fast and practical anatomical landmark for identification of the transverse-sigmoid-sinus-transition, without affecting operative fluency, especially during an emergency craniotomy.

A rare trifocal presentation of a choroid plexus papilloma: Case report and review of the literature.

Introduction: CPP's present as slow-growing intraventricular neoplasms arising from epithelium of choroid plexus. They account for approximately 0.5-4% of intracranial neoplasms in adults and children, respectively. A trifocal presentation is exceedingly rare. Research question: We describe the case of a trifocal presentation of a CPP and explored the importance of genetic analyses. Material and methods: We present the case of an 18-year old adolescent who was treated for a fourth ventricular and suprasellar neoplasm. Brain MRI revealed an intraventricular lesion in the fourth ventricle, as well as a suprasellar lesion and a lesion located in the left internal auditory meatus. An adult-subtype CPP (WHO grade 1) was confirmed by means of histological and genetic analyses in the first two regions. Results: Optimal treatment strategy remains controversial, although it is accepted that surgical resection alone remains the gold standard, whereas chemoradiotherapy is reserved for specific cases. There are only a few articles reporting on a multifocal presentation or the coexistence of synchronous histologically different primary brain neoplasms. Reports on genetic examination are scarce. Discussion and conclusion: CPP's should be included in the differential diagnosis of posterior fossa tumors, both in children and adults. Genetic analyses (TP53/TERT mutations) should be considered, since they entail important diagnostic, prognostic and therapeutic implications. When a TERT mutation is present, adjuvant radiotherapy should be used with caution, since it plays a role in tumorigenesis, even when GTR could not be achieved. There is an association between TERT methylation status and malignant transformation, indicating that these patients should be followed more closely.

Unraveling cerebral saccular aneurysm mimics: Case report and review of the literature.

Introduction: Aneurysm mimics, such as an occluded cerebral artery, vascular loops or infundibular dilatations, should be beard in mind when planning a craniotomy for the treatment of an aneurysm. Although ischemic stroke caused by clot migration from an aneurysmal cavity has been described, an ischemic event should raise awareness of potential MCA branch occlusion instead of an aneurysm. Research question: We provided a scaffold that could be used to differentiate other saccular aneurysm mimics. We explored the current literature concerning ACM segment occlusions initially misdiagnosed as a saccular aneurysm. Material and methods: We present the case of a 58 year old female who experienced a subarachnoid hemorrhage. CT angiography could not reveal an underlying aneurysm. She had a medical history of right carotid artery occlusion with secondary ischemic stroke and left spastic hemiparesis. An aneurysm of the right MCA was suspected and she was scheduled for explorative craniotomy. Results: Peroperatively we did not encounter an aneurysm, although a thrombosed branch of the right MCA was noted. The most proximal part of the branch was still patent, mimicking a saccular aneurysm on angiographic records. Discussion and conclusion: Aneurysm mimics can potentially expose patients to unnecessary exploratory craniotomies in the presumptive diagnosis of a saccular aneurysm. MRI 3D-CISS can be a helpful adjunct, since MRA and DSA are frequently not sufficient. Although ischemic stroke can be caused by clot migration from an aneurysmal cavity, an ischemic event should raise awareness of potential cerebral artery occlusion.

Intraneural ganglion cyst of the common peroneal nerve causing foot drop in a 12-year old child.

OBJECTIVES: Intraneural ganglia are benign fluid-filled cysts contained within the subepineurial space of peripheral nerves. The common peroneal nerve at the fibular neck is by far the most frequently involved, although other nerves can be affected as well. Although the differential diagnosis of foot drop in adults and children show some differences, clinical presentation, diagnostic workup, treatment and follow-up of intraneural ganglia are quite similar in both groups. The primary objective was to create an overview of intraneural ganglia in children, with an emphasis on diagnostic workup and potential pitfalls during neurosurgical intervention, based on all available literature concerning this topic and own center experiences. As a secondary objective, we tried to raise the awareness concerning this unique cause of foot drop in childhood. PATIENTS AND METHODS: We performed a review of the literature, in which children who developed foot drop secondary to an intraneural ganglion cyst of the common peroneal nerve were examined. A total of eleven articles obtained from MEDLINE were included. Search terms included: "pediatric", "children", "child", "intraneural ganglia", "intraneural ganglion cysts", "foot drop", "peroneal nerve" and "fibular nerve". Additional studies were identified by checking reference lists. Furthermore, we present the case of a 12-year old girl with foot drop caused by an intraneural ganglion cyst. She underwent cyst decompression with evacuation of intraneural cyst fluid and articular branch disconnection. PRISMA and CARE statement guidelines were followed. RESULTS: We hypothesize that minor injury caused a breach in the joint capsule, resulting in synovial fluid egression along the articular nerve branch, corroborating the unifying articular theory and emphasizing the need for ligation of said branch. Foot drop is a predominant characteristic, explained by the proximity of the anterior tibial muscle motor branch near the articular branch nerve. In children, satisfactory motor recovery after surgical decompression is to be expected. CONCLUSION: Sudden or progressive foot drop in children warrants an exhaustive neurophysiological and radiological workup. The management of intraneural ganglia is specific, consisting of nerve decompression, articular branch ligation and joint disarticulation, if deemed necessary. Our surgical results support the unifying articular theory and emphasize the importance of ligation and transection of the articular branch nerve, distally from the anterior tibial muscle branch, in order to prevent intraneural ganglia recurrence. This well-documented case adds depth to the current literature on this sparsely reported entity.

The external carotid artery as a rare feeder of a spinal dural arteriovenous fistula causing cervical myelopathy: A review of the literature.

Introduction: A causal relationship between SDAVF's and cervical myelopathy is exceedingly rare. 1-2% of these lesions are located at the craniocervical junction of which 12% are caused by arterial feeders from the external carotid artery. A correct diagnosis can be challenging with a high rate of initial misdiagnosis. Research question: Which aspects constitute the most important potential pitfalls in the diagnostic workup and treatment of SDAVF's with feeders from the external carotid artery causing cervical myelopathy? Material and methods: We performed a PRISMA-guided review of the literature in which fourteen articles were included. We illustrate the diagnostic hazards through one of our own cases. Results: SDAVF's at the cervical segment contain unique clinical and radiographic characteristics which differ from those elsewhere. Cervical myelopathy is caused by a SDAVF in 2.3% of cases. Pitfalls are numerous and diagnosis can be challenging, due to a broad differential diagnosis, potential isolated lower extremity involvement and absence of spinal cord edema on MRI. MR-alterations not always correlate with fistula localization. Discussion and conclusion: A SDAVF should be part of the differential diagnosis in patients with subacute tetraparesis. When MRI shows signal alterations in combination with enlarged perimedullary vessels, a SDAVF should be suspected. Spinal angiography should include the vertebrobasilar system, as well as the internal and external carotid arteries. Early and adequate occlusion by means of an endovascular or neurosurgical approach of the draining radicular veins should be pursued. A multidisciplinary approach is key in the diagnostic workup and treatment of these patients.

Tuberculous spondylitis following intravesical bcg-instillation in the treatment of transitional cell carcinoma: Case report and systematic review.

OBJECTIVES: Tuberculous spondylitis (TS), also known as Pott's disease (PD), is a form of tuberculosis in which the vertebral column is affected. Since the first description by Katz et al. in 1992, it became clear that Bacillus Calmette-Guérin (BCG) instillations in the treatment of superficial transitional cell carcinoma (TCC) form a plausible way in which PD is introduced. Nowadays, BCG forms the most effective treatment modality for superficial TCC. The incidence of other than minor complications have been estimated under five per cent. Here we report a case of TS after BCG-instillation in the treatment of TCC. Furthermore, all available literature concerning this topic was gathered into a systematic review. The primary objective was to create an overview of all available literature concerning TS after intravesical BCG-instillations, with an emphasis on the neurosurgical approach of these patients, forming a scaffold at which future case reports can be compared. As a secondary objective, we tried to raise the awareness concerning this very rare complication of intravesical BCG-instillation as a possible cause of low back pain (LBP). PATIENTS AND METHODS: We performed a systematic review, in which patients who developed TS after intravesical BCG-therapy in the treatment of TCC, were examined. A total of twenty-three articles (twenty-four cases) obtained from MEDLINE were included. Search terms included: "tuberculous spondylitis", "Pott's disease", "vertebral osteomyelitis", "intravesical", "Bacillus Calmette-Guérin" and "transitional cell carcinoma". Additional studies were identified by checking reference lists. Furthermore, we present a case concerning one of our own patients who consulted our Neurosurgical department with a similar clinical presentation. This systematic review is in conformity with the PRISMA-guidelines. The case report is in accordance with the CARE statement guidelines. RESULTS: Results are based on twenty-five cases (twenty-four cases extracted from previous literature and our case report). All included articles are case reports written in English. Publication year and recruitment time varies from 1992 to 2018. Mean age at clinical presentation varies from 35 to 94 years old (mean 74). All patients were male. Surgery was performed in 17 out of 25 cases (68%). A posterior approach was performed in seven cases (41%), zero anterior approaches (0%), a combined approach in five cases (29%) and not specified in five cases (29%). All patients received intravesical BCG-instillation in the treatment of TCC, ranging from one month to twelve years before clinical presentation (mean 26). Radiographic abnormalities were seen in thoracic vertebral segments in thirteen cases (52%), eleven cases in lumbar segments (44%), one at the thoracolumbar transition level (4%) and not in cervical vertebral segments. CONCLUSION: Although very rare, TS should be part of the differential diagnosis in patients with LBP, even years after BCG-instillation for TCC. It mostly affects elderly men and involves the thoracolumbar spine through hematogenous spread via Batson's plexus. Antitubercular therapy remains the mainstay in the treatment of TS. A posterior surgical approach, with debridement and stabilization, should be preferred when surgical intervention seems necessary. To our knowledge, this systematic review forms one of the first comprehensive reviews evaluating neurosurgical intervention for PD following intravesical BCG-therapy in the treatment of TCC.

5-Aminolevulinic acid for recurrent malignant gliomas: A systematic review.

OBJECTIVES: Nowadays, several techniques have been developed in order to guide neurosurgeons during intended maximal safe resection of high-grade gliomas (HGG). Fluorescence-guided microsurgery using 5-aminolevulinic acid (5-ALA) is one of these. A large amount of studies have been performed evaluating benefits in newly diagnosed HGG. However, little is known about the safety, accuracy and efficacy in recurrent HGG. The primary objective of this thesis is to examine the value of 5-ALA in patients with recurrent HGG concerning diagnostic accuracy, extent of resection (EOR), safety and survival compared to white-light resection. As a secondary objective, we compared these results with current literature concerning 5-ALA in newly diagnosed HGG. PATIENTS AND METHODS: We performed a systematic review and included eighteen articles obtained from MEDLINE, EMBASE, Web of Science and TRIP database. Search terms include "glioma" and "aminolevulinic acid". Additional studies were identified through checking the reference lists. This study is in conformity with the PRISMA and BMJ guidelines. RESULTS: 5-ALA shows similar results regarding diagnostic accuracy in recurrent HGG compared to newly diagnosed HGG, although specificity and negative predictive value seem lower. It shows complementary value in identifying tumor boundaries compared to MRI-neuronavigation. Diagnostic accuracy is not influenced by previous chemo- or radiotherapy. New neurological deficits proved to be similar and were in general mainly temporary. However, adverse events overall were more common. Therefore, indications for repeat surgery should be followed strictly. 5-ALA might increase overall survival in recurrent gliomas, but has no clear impact on progression-free survival. CONCLUSION: 5-ALA should be regarded as a useful and safe intraoperative tool in recurrent glioma surgery.

External neurolysis as a treatment for foot drop secondary to weight loss: a retrospective analysis of 200 cases.

BACKGROUND: Peroneal nerve entrapment is the most common peripheral mononeuropathy of the lower limbs. Foot drop, a common presentation, leads to an impaired eversion and dorsiflexion of the foot. An intriguing observation is the occurrence of foot drop secondary to weight loss. METHODS: A retrospective study of patients surgically treated for peroneal nerve entrapment was performed between January 1, 1995 and December 31, 2016, at the Department of Neurosurgery, Genk, Belgium. Out of a total of 421 patients, 200 patients with foot drop secondary to weight loss were included. For each subject, motor and sensory outcomes after external neurolysis were investigated. As a primary objective, we examined the postoperative outcomes of external neurolysis as a treatment for foot drop in patients with peroneal nerve entrapment at the fibular head secondary to weight loss. As a secondary objective, we analyzed the correlation between patient characteristics and the success rate of external neurolysis. RESULTS: When defining success as a postoperative MRC score of 4 or 5, external neurolysis has a success rate of 85% in patients with foot drop secondary to weight loss. A significant difference (P = < 0.0001) between postoperative and preoperative MRC scores indicates that external neurolysis leads to significant improvement of motor function in patients with foot drop secondary to weight loss. A multiple logistic regression model showed that "preoperative MRC scores" and "duration of symptoms" were the only variables with an impact on postoperative MRC scores. Other variables such as "age," "gender," and "side of entrapment" had no significant impact on postoperative results. CONCLUSIONS: Statistical analysis emphasizes the important role of external neurolysis in the treatment of peripheral peroneal nerve entrapment. Therefore, external neurolysis at the fibular head should be regarded as a very effective and safe procedure in patients with foot drop secondary to weight loss.