Syringosubarachnoid shunt: insertion technique.

BACKGROUND: Syringomyelia is a rare disorder but its impact on patients' quality of life can be devastating. The exact pathophysiology remains unknown; the syrinx can either be idiopathic or associated with conditions such as Chiari malformation, scoliosis, malignancy, infection and trauma. Several techniques have been described to decompress syringomyelia with distal drainage to the subarachnoid space, pleura or peritoneum. METHOD: We present a modification of the syringosubarachnoid shunt insertion technique with minimal myelotomy and the use of a T shaped shunt which does not require suturing to the pia matter to prevent shunt migration. CONCLUSION: This technique for syringosubarachnoid shunt insertion is likely to prevent shunt migration and scarring whilst minimizing suturing and optimising syrinx decompression.

A novel case of paravertebral glomangiomyomatosis.

Glomangiomyomatosis is an extremely rare variant of glomus tumours. We describe the first known case of paravertebral glomangiomyomatosis in the literature to cause spinal cord compression. A 45-year old female patient presented with sudden onset of left leg pain and progressive weakness in left-sided hip flexion. An MRI spine revealed a large, lobulated, heterogeneous mass cantered on the left L2/3 foramen, mimicking a dumbbell nerve sheath tumour. The mass was invading the psoas muscle and displayed evidence of recent haemorrhage. The patient underwent debulking of the lesion via a left retroperitoneal approach. Surgery was uneventful, with clinical improvement and resolution of leg pain post-operatively. Histopathology of the tumour revealed delineated glomus-like cells and foci of spindled shaped cells resembling myoid differentiation. Immuno-histochemical features of the tumour confirmed the diagnosis of glomangiomyomatosis. The patient continued under close follow up, representing 18 months later with clinical and radiological progression of the disease with similar symptoms of leg pain but no weakness. Follow up MRI revealed progression of the intraspinal and paraspinal components of the tumour with thecal compression. A posterior approach was utilized in order to decompress the intraspinal component, which again was uneventful, and improved the patient's symptoms. This is the first known case of paravertebral glomangiomyomatosis in the literature and this rare entity should be considered in the differential diagnosis of nerve sheath tumours due to risk of progression and recurrence.

CSF rhinorrhoea after endonasal intervention to the anterior skull base (CRANIAL): proposal for a prospective multicentre observational cohort study.

BACKGROUND: The endonasal transsphenoidal approach (TSA) has emerged as the preferred approach in order to treat pituitary adenoma and related sellar pathologies. The recently adopted expanded endonasal approach (EEA) has improved access to the ventral skull base whilst retaining the principles of minimally invasive surgery. Despite the advantages these approaches offer, cerebrospinal fluid (CSF) rhinorrhoea remains a common complication. There is currently a lack of comparative evidence to guide the best choice of skull base reconstruction, resulting in considerable heterogeneity of current practice. This study aims to determine: (1) the scope of the methods of skull base repair; and (2) the corresponding rates of postoperative CSF rhinorrhoea in contemporary neurosurgical practice in the UK and Ireland. METHODS: We will adopt a multicentre, prospective, observational cohort design. All neurosurgical units in the UK and Ireland performing the relevant surgeries (TSA and EEA) will be eligible to participate. Eligible cases will be prospectively recruited over 6 months with 6 months of postoperative follow-up. Data points collected will include: demographics, tumour characteristics, operative data), and postoperative outcomes. Primary outcomes include skull base repair technique and CSF rhinorrhoea (biochemically confirmed and/or requiring intervention) rates. Pooled data will be analysed using descriptive statistics. All skull base repair methods used and CSF leak rates for TSA and EEA will be compared against rates listed in the literature. ETHICS AND DISSEMINATION: Formal institutional ethical board review was not required owing to the nature of the study - this was confirmed with the Health Research Authority, UK. CONCLUSIONS: The need for this multicentre, prospective, observational study is highlighted by the relative paucity of literature and the resultant lack of consensus on the topic. It is hoped that the results will give insight into contemporary practice in the UK and Ireland and will inform future studies.

How many patients require brain mapping in an adult neuro-oncology service?

Intraoperative mapping and neuromonitoring is an established technique to maximise tumour resection while minimising the risk of inducing permanent postoperative deficit. However, very little is known on how many patients require brain mapping within a general adult neuro-oncology service. A prospective study of all neuro-oncology patients operated over a 12 months' period (January-December 2017) was performed. All patients were seen in a dedicated neuro-oncology pre-assessment clinic after discussion in a neuro-oncology multidisciplinary team meeting. Inclusion criteria for brain mapping were age more than 18, performance status less than 2, tumour location in an eloquent area. Age, sex, histology, surgical technique, extent of resection and operative complications were analysed. Two hundred thirty-five craniotomies were performed in the study period. Intraoperative mapping was used for 57 (24%) cases. There were 22 females and 35 males; median age was 52 years (22-73).17 (30%) patients were operated awake for speech and 40 (70%) asleep for motor mapping. One hundred fifteen patients had a diagnosis of glioma; of these, 48 (42%) were operated with intraoperative mapping. Age (48.92 ± 2.18versus 58.43 ± 1.63, p = 0.001) and WHO grading were significantly lower in the mapping group and the extent of resection was significantly higher (GTR-81.25% versus 37.3%, p < .001). Within the mapping group, the awake subgroup had a better performance status (p = 0.039), less glioblastomas as histological diagnosis (p < 0.05) and an increased proportion of tumours in both temporal and insular locations (p < 0.05). Intraoperative mapping was employed in almost one quarter of our general adult neuro-oncology population. Four in 10 gliomas were operated with intraoperative mapping. This percentage reflects the need for specialised training in brain mapping and budget allocation within the neuro-oncology department.

Safety and accuracy of frameless electromagnetic-navigated (AXIEMTM)-guided brain lesion biopsies: a large single-unit study.

BACKGROUND: Brain biopsies are required to establish a definitive histological diagnosis for brain lesions that have been identified on imaging in order to guide further treatment for patients. OBJECTIVE: Various navigation systems are in use but little up to date evidence is available regarding the safety and accuracy of a frameless, electromagnetic technique to target brain lesions. METHODS: Data was collected retrospectively on all patients that had brain biopsies at our institution from 01/01/2010 to 31/12/2017. Operation notes, neuropathology reports, and clinical notes on electronic patient record were used to determine whether biopsy of adequate identifiable abnormal tissue was achieved, whether a definitive diagnosis was established, any adverse events occurred, and if a repeat biopsy was carried out. RESULTS: Three hundred seventy-one AxiEM (Medtronic, Minneapolis, USA)-guided brain tumor biopsies were performed in this 8-year period. Three hundred forty-nine (94.07%) procedures provided definitive tissue diagnosis, 22 (5.93%) were non diagnostic; in 6 cases (1.62%), repeat biopsy was performed and adverse events which caused clinical compromise were observed in 4 patients (1.08%). CONCLUSIONS: The AxiEM is a fast, effective, and safe frameless and pinless neuronavigational system. It offers a high degree of accuracy required for the establishment of a definitive diagnosis, permitting optimal further treatment, and thus improving patient outcomes.

Impact of remoteness and rurality on the treatment and survival of patients with glioblastoma in the north of Scotland.

Background: The geographical catchment area served by the Neurosurgical Unit in Aberdeen, Scotland is the largest in the United Kingdom. We examined whether a distance-decay effect on survival exists for patients diagnosed with glioblastoma, who have to travel substantial distances for neurosurgical and oncological treatment in the north of Scotland. Methods: Electronic medical records of adult patients with glioblastoma, referred for treatment between 2007 and 2018, who underwent surgical resection were reviewed. Travel time by car (as a measure of distance travelled) was calculated from the patients' home to their general practice (GP) and to their main neuro-oncological centre. Results: There were 122 patients; 71 (58.2%) were male and the mean age was 57.8 years. The urban-rural split was 61.5% and 38.5%, respectively. Median driving time to the neuro-oncological centre was 36 min and to the GP this was 6 min. Most patients underwent either sub-total (49.6%) or gross total (46.3%) surgical resection. Post-operative treatments included: radiotherapy only (15.6%), chemotherapy only (6.6%), and chemotherapy with radiotherapy (63.1%). Temozolomide was used in 70.5% of patients. Seventeen patients did not receive any post-operative chemo-radiotherapy. The median survival time was 345 days. There was no statistically significant association between distance travelled and survival time in days. MGMT methylation status, extent of resection, Charlson co-morbidity index and treatment received significantly affected survival. Conclusions: There was no evidence of disadvantage on survival time for patients living further from their neuro-oncological centre compared to those who live nearer.

5-Aminolevulinic Acid-Guided Resection in Grade III Tumors-A Comparative Cohort Study.

BACKGROUND: The benefits of using 5-aminolevulinic acid (5-ALA) in resection of grade IV tumors have been extensively researched. However, few studies have investigated the use of 5-ALA in grade III gliomas. OBJECTIVE: To discover whether 5-ALA provides significant benefit in assisting resection of grade III gliomas. METHODS: A single-center, retrospective cohort study between January 2013 and January 2019 of adult patients with grade III gliomas. Patients were separated into a 5-ALA-guided surgery group (5-ALA-GS) and non-5-ALA-guided surgery group (non-5-ALA-GS). Primary outcome was overall survival (OS); secondary outcomes were both postoperative and 6-month performance status (PS6m), and extent of resection (EoR). RESULTS: Sixty-nine patients with grade III gliomas were included (39 and 30 patients in the 5-ALA-GS group and non-5-ALA-GS group, respectively). There was no significant difference in tumor characteristics between the groups. No significant difference was observed in OS (P = .072) and EoR (P = .609) between both the groups. In a subgroup of the 5-ALA-GS where gross total resection (GTR) was achieved, there was a better OS (P = .043). Significantly worse outcomes were seen postoperatively (P = .044) and at PS6m (P = .041) in the 5-ALA-GS group, mainly because of the poorer outcome in the subtotal resection subgroup. CONCLUSION: Despite the benefits of 5-ALA in grade IV glioma surgery, these benefits are limited to a smaller group of patients with grade III tumors where there is sufficient fluorescence to allow GTR. In this cohort of patients, 5-ALA use may result in worse neurological outcomes particularly when GTR is not feasible and therefore caution is warranted.

5-Aminolevulinic acid-guided resection improves the overall survival of patients with glioblastoma-a comparative cohort study of 343 patients.

BACKGROUND: 5-Aminolevulic acid-guided surgery (5-ALA-GS) improves the extent of resection (EoR) and progression-free survival in patients with glioblastoma multiforme (GBM). METHODS: A single-center retrospective cohort study of adult patients with GBM who had surgical resection between 2013 and 2019, 5-ALA guided versus a non-5-ALA cohort. The primary outcome was the overall survival (OS). Secondary outcomes were EoR, performance status (PS), and new focal neurological deficit. RESULTS: Three hundred and forty-three patients were included: 253 patients in 5-ALA-GS group and 90 patients in the non-5-ALA-GS group. The OS (17.47 vs 10.63 months, P < .0001), postoperative PS (P < .0001), PS at 6 months (P = .002), new focal neurological deficit (23.3% vs 44.9%, P < .0001), and radiological EoR (gross total resection [GTR]-47.4% vs 22.9%, P < .0001) were significantly better in the 5-ALA-GS group compared to non-5-ALA-GS group. In multivariate analysis, use of 5-ALA (P = .003) and MGMT promoter methylation (P = .001) were significantly related with a better OS. In patients with radiological GTR, OS was also significantly better (P < .0001) in the 5-ALA-GS group compared to the non-5-ALA-GS group. CONCLUSIONS: 5-ALA-GS is associated with a significant improvement in the OS, PS after surgery and at 6 months, larger EoR, and fewer new motor deficits in patients with GBM.

Endoscopic removal of recurrent colloid cysts.

OBJECTIVE: Removal of colloid cysts of the third ventricle using a purely endoscopic method has been established as a safe and advantageous technique. It is hypothesized that endoscopic removal in recurrent cases might pose more technical challenges and result in less success. The objective of this study was to assess the feasibility and outcomes of using a purely endoscopic approach for the management of recurrent colloid cysts compared to primary cysts. METHODS: A retrospective cohort study was performed on patients who underwent purely endoscopic removal of their colloid cyst. Descriptive statistics were compared for patients undergoing surgery for a recurrent cyst and those for a control cohort undergoing surgery for a primary cyst. Bivariate analysis was conducted using a Fisher's exact test for categorical variables and Mann-Whitney U-test for continuous variables. RESULTS: In total, 121 patients had a primary colloid cyst endoscopically removed and 10 patients had a total of 11 recurrent cysts removed. Recurrence or progression after surgery occurred in 3 (2.5%) cases in the primary cyst group and 2 (18.2%) cases in the recurrent cyst group. Symptomatic presentation during the follow-up period occurred in 6 (54.5%) cases in the recurrent cyst group versus 75 (62%) cases in the primary cyst group (p = 0.749). Two patients (20%) in the recurrent group had a second recurrence in a mean period of 30 months (1 patient at 15 and 1 patient at 45 months). One of these patients required a tertiary endoscopic removal 8 years after the second resection. No immediate postoperative complications or new morbidities were observed after repeat endoscopic surgery. The authors' findings indicated a nonsignificant trend toward a higher recurrence rate (18.2% vs 2.5%, p = 0.055) and a decreased proportion of complete removal (90.9% vs 81.8%, p = 0.296) in the recurrent cyst group compared to the primary cyst group. However, a significantly higher rate of preoperative hydrocephalus was observed in the primary cyst group compared with the recurrent cyst group (63.6% vs 18.2%, p = 0.007). CONCLUSIONS: Purely endoscopic approaches for the removal of recurrent colloid cysts of the third ventricle are feasible and equally safe compared with endoscopic removal of primary cysts. The study's findings did not show a statistically significant difference in the rate of recurrence between the 2 groups. The proportion of patients with symptomatic cysts on presentation was lower in patients with recurrent cysts than in patients with primary cysts. Due to the high rate of complete removal with negligible morbidity, the authors continue to advocate for an endoscopic removal at the time of cyst recurrence.

Navigated Transcranial Magnetic Stimulation in Patient with Cranioplasty in Situ: Safe and Accurate Procedure.

BACKGROUND: Navigated transcranial magnetic stimulation (nTMS) is a nonsurgical mapping technique used in mapping of motor and language eloquent areas within and/or surrounding brain tumors. Previous reports support this as a safe technique with minor side effects associated with minor headaches and discomfort around the stimulation area. Currently there are no published reports concerning the accuracy and safety of this procedure in patients with a titanium cranioplasty in situ. CASE PRESENTATION: A 59-year-old lady was diagnosed with a recurrent glioma in the context of increasing seizure frequency, left-sided numbness, and weakness. She was diagnosed with a World Health Organization grade 2 oligodendroglioma 10 years before her presentation, which was initially treated with radiotherapy and then surgical resection of this lesion 5 years later. The procedure was complicated with a wound infection, treated with a craniectomy and wound washout, followed by a titanium cranioplasty. Before proceeding with surgery for recurrence, nTMS was performed for motor mapping. No complications were identified. She underwent a craniotomy for tumor resection with aminolevulinic acid HCl (Gliolan), and the tumor was completely removed. Intraoperatively, the direct cortical stimulation correlated with the preoperative nTMS. The pathologic diagnosis on recurrence was an anaplastic oligodendroglioma grade III, and the patient is currently undergoing adjuvant chemotherapy. CONCLUSION: This report confirms that nTMS is a safe and accurate procedure in patients who have a titanium cranioplasty in situ.

First United Kingdom Experience of Navigated Transcranial Magnetic Stimulation in Preoperative Mapping of Brain Tumors.

BACKGROUND: Surgery for lesions in eloquent brain areas remains challenging owing to the risk of permanent neurological deficits. To date, direct electrical stimulation (DES) and intraoperative neuromonitoring represent the reference standard. Recently, navigated transcranial magnetic stimulation (nTMS) has emerged as a mapping tool to optimize surgical planning. Our aim was to correlate nTMS with the intraoperative findings and assess its effects on surgical decision-making. METHODS: We retrospectively reviewed our series of patients who had undergone craniotomy for removal of a brain tumor at our institution with preoperative nTMS, intraoperative neuromonitoring, and DES from February 2017 to February 2018. Demographic data, tumor entity and location, extent of resection, change in surgical approach, and neurological outcome were collected. RESULTS: Of 35 patients, 24 (68.6%) had undergone preoperative motor mapping and 11 (31.4%) had undergone mapping for language. Histopathological examination demonstrated glioma in 88.6% (high grade, n = 24; low grade, n = 6), metastasis (n = 2), epidermoid cyst (n = 1), and cavernoma (n = 1). nTMS resulted in change in the surgical strategy in 31.5% (craniotomy size, n = 7; access pathway, n = 3; surgical indication, n = 1). The specificity of nTMS for language was 66.7%, with a negative predictive value of 74.1%. nTMS motor mapping correlated with DES in all cases, with a mean abductor pollicis brevis hotspot distance of 3.50 ± 0.66 mm (n = 9). CONCLUSIONS: nTMS is a safe, noninvasive adjunctive tool for preoperative mapping of brain tumors in eloquent areas. Furthermore, nTMS can influence the surgical decisions in up to one third of patients in our experience.

Somatotopy of corticospinal tract fibres of the intercostal muscles: report of a case and review of literature.

This study aimed at describing the first case of subcortical stimulation of the corticospinal tract leading to selective contraction of the intercostal muscles during surgery for removal of a tumour centred in the right central lobule/supplementary motor area. A 53-year-old male presented with partial motor seizures. Imaging demonstrated a low-grade glioma affecting the posterior aspect of the superior and middle frontal gyri and invading the precentral gyrus. Preoperative motor Transcranial Magnetic Stimulation and advanced diffusion tractography were performed to establish the relationship of the tumour with the motor cortex and corticospinal tract. Intraoperative motor mapping and monitoring were performed with monopolar stimulation ("train of 5" technique). At the posterior margin of resection, subcortical stimulation demonstrated a selective response from intercostal muscles, medial to responses from the lower limb and lateral to responses from the upper limb. PubMed literature search was performed to identify any case reporting similar findings. There were no cases previously reported in the literature. The location of the subcortical response for intercostal muscles confirms the somatotopy of the corticospinal tract. Intercostal muscles are controlled by selective fibres within the corticospinal tract. Damage to these fibres can lead to paralysis of voluntary respiratory muscles. Further studies are needed to define the cortico-subcortical network controlling voluntary respiratory muscles.

Spinal myoclonus: a rare presentation of cervical myelopathy.

Myoclonus describes a movement disorder characterised by brief, abrupt and involuntary contractions of muscles or groups of muscles, usually associated with intracranial lesions, with limited evidence linking it to spinal pathologies. The pathophysiology of spinal myoclonus is extensive and multifactorial. Infection, intramedullary and extramedullary space-occupying lesions, trauma, vascular abnormalities, degenerative processes and cervical spondylosis have been implicated with the disease, the latter been associated with cervical stenosis with no reported cases linking it to an underlying cervical disc herniation. Although medical therapy with clonazepam, levetiracetam, valproate, tetrabenazine hydrochloride and spinal block injections has been equivocal, spinal myoclonus secondary to disc herniation requires surgical intervention. This report describes a case of segmental spinal myoclonus, secondary to a herniated cervical intervertebral disc. After corpectomy and a cage-augmented fusion technique, the myoclonic symptoms resolved. To our knowledge, this was the first report to describe the successful management of discogenic spinal myoclonus with spinal surgery.

Primary intracerebral INI1-deficient rhabdoid tumor with CD34 immunopositivity in a young adult.

BACKGROUND: Primary CNS malignant rhabdoid tumors are very rare in adults and much less is known about their biological behavior than in children. Recently, two adult cases of SMARCB1 (also known as INI1)-deficient tumor with rhabdoid cells have been described, suggesting an emerging group of primary meningeal SMARCB1-deficient tumors. We have recently encountered a case of INI1-deficient tumor with similar histology and immunophenotype to the above cases, but with a superficial cerebral, yet apparent intra-axial origin. CASE DESCRIPTION: A 22-year-old woman presented with approximately one year history of focal sensorimotor right upper limb seizures and recently developed a slowly progressive weakness in her right hand. An MRI of the brain demonstrated an avidly enhancing lesion centered on the left perirolandic region with no definite dural involvement. The patient underwent a complete surgical excision. Histology revealed a tumor with monotonous epithelioid and spindle-shaped cells in a mucoid/myxoid background. There was focal mitotic activity and a few necrotic areas, in addition to many rhabdoid cells. The immunohistochemistry was negative for INI1 and there was strong positivity with CD34, while focal smooth muscle actin (SMA) and epithelial membrane antigen (EMA) immunoreactivity were also noted. CONCLUSIONS: As an addition to the two cases of adult SMARCB1-deficient tumors recently described, we present a further adult case with a similar immunohistochemical profile but with an apparent intra-axial origin, questioning the necessary meningeal origin of this type of tumor. The prognosis of this adult INI1/SMARCB1-deficient tumor is to be determined, but may be better than the pediatric atypical/teratoid tumor (AT/RT).

Spinal subdural hematoma post foramen magnum decompression-rare complication in a patient with rhomboencephalosynapsis.

Spinal subdural hematoma (SSDH) as a complication of posterior fossa surgery is extremely rare and can have potentially serious consequences. We report a case of delayed extensive SSHD presenting as cauda equina syndrome (CES) following foramen magnum decompression and occipito-cervical (OC) fusion.

Thoracic Arachnoid Cyst Made Symptomatic by Demyelination.

Spinal arachnoid cysts are uncommon distinct pouches of cerebrospinal fluid (CSF) or CSF-like fluid found adjacent to normal CSF spaces commonly extradural and rarely intradural. They are usually asymptomatic and discovered incidentally. We present a patient with rapid upper motor neuron neurologic deterioration over the course of 1 week. Findings on magnetic resonance imaging revealed various central nervous system demyelination lesions and thoracic arachnoid cyst with cord compression. This acute presentation, in the absence of trauma, is not in favor of the natural history of the intradural thoracic arachnoid cysts. The patient's sensory, gait, and lower limb neurologic deficits improved after surgery with residual mild but stable upper limb deficits. Our patient likely had a static compensated cyst made symptomatic by demyelination as an additional central nervous system lesion.