Usability of mixed reality in awake craniotomy planning.

PURPOSE: This study aimed to describe our institutional use of a commercially available mixed reality viewer within a multi-disciplinary planning workflow for awake craniotomy surgery and to report an assessment of its usability. MATERIALS AND METHODS: Three Tesla MRI scans, including 32-direction diffusion tensor sequences, were reconstructed with BrainLab Elements auto-segmentation software. Magic Leap mixed reality viewer headsets were registered to a shared virtual viewing space to display image reconstructions. System Usability Scale was used to assess the usability of the mixed reality system. RESULTS: The awake craniotomy planning workflow utilises the mixed reality viewer to facilitate a stepwise discussion through four progressive anatomical layers; the skin, cerebral cortex, subcortical white matter tracts and tumour with surrounding vasculature. At each stage relevant members of the multi-disciplinary team review key operative considerations, including patient positioning, cortical and subcortical speech mapping protocols and surgical approaches to the tumour.The mixed reality system was used for multi-disciplinary awake craniotomy planning in 10 consecutive procedures over a 5-month period. Ten participants (2 Anaesthetists, 5 Neurosurgical trainees, 2 Speech therapists, 1 Neuropsychologist) completed System Usability Scale assessments, reporting a mean score of 71.5. Feedback highlighted the benefit of being able to rehearse important steps in the procedure, including patient positioning and anaesthetic access and visualising the testing protocol for cortical and subcortical speech mapping. CONCLUSIONS: This study supports the use of mixed reality for multidisciplinary planning for awake craniotomy surgery, with an acceptable degree of usability of the interface. We highlight the need to consider the requirements of non-technical, non-neurosurgical team members when involving mixed reality activities.

Primary lumbar decompression using ultrasonic bone curette compared to conventional technique.

PURPOSE: The ultrasonic bone curette (Bone Scalpel) is a novel technique in neurosurgery for bony dissection. This study aimed to evaluate its use against conventional techniques for primary lumbar decompression. MATERIALS AND METHODS: This study was a retrospective cohort comparison, using Spine Tango Registry data. All patients undergoing a primary procedure for lumbar decompression secondary to degenerative disease during a 2-year period (2014-2016) were identified, split into age and gender matched cohorts utilising either bone scalpel or conventional techniques intra-operatively. RESULTS: Ninety-three patients were identified within each cohort, which did not differ significantly in terms of age, gender, BMI, number of operative vertebral levels or seniority of the principal surgeon. The incidence of intra-operative blood loss >100 ml was significantly reduced within the bone scalpel cohort (16.1% bone scalpel, 34.4% conventional, p = 0.04). There was no difference in the incidence of iatrogenic dural breach (9.7% bone scalpel, 16.1% conventional, p = 0.27). There was no significant difference in pre-operative Core Outcomes Measures Index (COMI) between the cohorts (7.91 bone scalpel, 8.02 conventional, p = 0.67) and both cohorts demonstrated a significant reduction in mean COMI at 24 months (bone scalpel p = 0.004, conventional p = <0.001). No difference in mean COMI existed between either cohort at any point across the 24-month post-operative period (p = 0.18). CONCLUSIONS: The use of ultrasonic bone curette for primary lumbar decompression is associated with reduced intra-operative blood loss compared to conventional techniques, alongside a comparable safety profile and equivalent patient reported outcomes.

Correction to: Incidental intracranial meningiomas: a systematic review and meta-analysis of prognostic factors and outcomes.

Issues with data analysis have recently been highlighted by a reader of our article. These have been addressed with changes to Tables 2&4, as shown below, and Online Resources 5-7. T2 and peritumoral signal are no longer prognostic factors on simple pooled (Online Resource 5) and IPD (Table 4) analyses respectively. In Table 5, the number of patients which informed the outcomes symptom development and intervention were 575 and 947 respectively; 69 developed symptoms (pooled proportion %8.4 [95% CI 2.8-16.7], I2 = 88.9%). These included motor and cognitive deficits (n = 1). We apologise to the readership of the Journal of Neuro-Oncology for these errors and thank the reader for helping us identify them.

Incidental intracranial meningiomas: a systematic review and meta-analysis of prognostic factors and outcomes.

BACKGROUND: Incidental discovery accounts for 30% of newly-diagnosed intracranial meningiomas. There is no consensus on their optimal management. This review aimed to evaluate the outcomes of different management strategies for these tumors. METHODS: Using established systematic review methods, six databases were scanned up to September 2017. Pooled event proportions were estimated using a random effects model. Meta-regression of prognostic factors was performed using individual patient data. RESULTS: Twenty studies (2130 patients) were included. Initial management strategies at diagnosis were: surgery (27.3%), stereotactic radiosurgery (22.0%) and active monitoring (50.7%) with a weighted mean follow-up of 49.5 months (SD = 29.3). The definition of meningioma growth and monitoring regimens varied widely impeding relevant meta-analysis. The pooled risk of symptom development in patients actively monitored was 8.1% (95% CI 2.7-16.1). Associated factors were peritumoral edema (OR 8.72 [95% CI 0.35-14.90]) and meningioma diameter ≥ 3 cm (OR 34.90 [95% CI 5.17-160.40]). The pooled proportion of intervention after a duration of active monitoring was 24.8% (95% CI 7.5-48.0). Weighted mean time-to-intervention was 24.8 months (SD = 18.2). The pooled risks of morbidity following surgery and radiosurgery, accounting for cross-over, were 11.8% (95% CI 3.7-23.5) and 32.0% (95% CI 10.6-70.5) respectively. The pooled proportion of operated meningioma being WHO grade I was 94.0% (95% CI 88.2-97.9). CONCLUSION: The management of incidental meningioma varies widely. Most patients who clinically or radiologically progressed did so within 5 years of diagnosis. Intervention at diagnosis may lead to unnecessary overtreatment. Prospective data is needed to develop a risk calculator to better inform management strategies.

The impact of major trauma centre implementation on the pathways and outcome of traumatic intracranial extradural haematoma in a regional centre.

INTRODUCTION: A new trauma care system with regional major trauma centres (MTC) was implemented on 1st April 2012 across England. We aimed to assess whether this has affected the referral pathways and mortality of patients undergoing emergency craniotomy for extradural haematoma (EDH), where clinical outcome is correlated with the time to intervention. MATERIALS AND METHODS: This was a retrospective cohort comparison study. All patients who had undergone evacuation of EDH from January 2011 to December 2013 were identified. Only those in whom a decision for emergency craniotomy had been made at the time of referral to the on-call neurosurgeon were included. The CRASH predicted risk of mortality was calculated for individual patients. Mortality was assessed at 14 days in order to compute standardised mortality ratios (SMR). RESULTS: Overall, 65 patients underwent EDH evacuation during the study period (21 pre-MTC and 44 post-MTC). Of those, 43 emergency procedures according to the aforementioned definition were included for further analysis (13 pre-MTC, 30 post-MTC). The mean CRASH predicted risk of mortality was 0.21 for the pre-MTC cohort (95% CI: 0.07-0.34) and 0.094 for the post-MTC cohort (95% CI: 0.039-0.15; p = 0.052). There was no significant difference in the rate of secondary transfers before and after MTC implementation (9/13 vs. 23/30, p = 0.71). The mean interval from referral to operation was 198 min for the pre-MTC cohort (95% CI: 123-273) and 201 min for the post-MTC cohort (95% CI: 141-262; p = 0.95). The SMR was 0.37 for the pre-MTC cohort (95% CI: 0.02-1.81; 1 death) and 0.71 for the post-MTC cohort (95% CI: 0.12-2.34; 2 deaths). CONCLUSIONS: MTC implementation has not affected the time to operation or the mortality following EDH evacuation.

Presentation, management, and outcomes of cauda equina syndrome up to one year after surgery, using clinician and participant reporting: A multi-centre prospective cohort study.

Background: Cauda equina syndrome (CES) results from nerve root compression in the lumbosacral spine, usually due to a prolapsed intervertebral disc. Evidence for management of CES is limited by its infrequent occurrence and lack of standardised clinical definitions and outcome measures. Methods: This is a prospective multi-centre observational cohort study of adults with CES in the UK. We assessed presentation, investigation, management, and all Core Outcome Set domains up to one year post-operatively using clinician and participant reporting. Univariable and multivariable associations with the Oswestry Disability Index (ODI) and urinary outcomes were investigated. Findings: In 621 participants with CES, catheterisation for urinary retention was required pre-operatively in 31% (191/615). At discharge, only 13% (78/616) required a catheter. Median time to surgery from symptom onset was 3 days (IQR:1-8) with 32% (175/545) undergoing surgery within 48 h. Earlier surgery was associated with catheterisation (OR:2.2, 95%CI:1.5-3.3) but not with admission ODI or radiological compression. In multivariable analyses catheter requirement at discharge was associated with pre-operative catheterisation (OR:10.6, 95%CI:5.8-20.4) and one-year ODI was associated with presentation ODI (r = 0.3, 95%CI:0.2-0.4), but neither outcome was associated with time to surgery or radiological compression. Additional healthcare services were required by 65% (320/490) during one year follow up. Interpretation: Post-operative functional improvement occurred even in those presenting with urinary retention. There was no association between outcomes and time to surgery in this observational study. Significant healthcare needs remained post-operatively. Funding: DCN Endowment Fund funded study administration. Castor EDC provided database use. No other study funding was received.

Slow-Growing Pituitary Metastasis from Renal Cell Carcinoma: Literature Review.

BACKGROUND: Tumor metastasis to the pituitary is rare, most commonly reported with either breast or lung cancer metastasizing to the neurohypophysis. Pituitary metastases of renal cell carcinoma (RCC) are by contrast infrequently described even within this scarce literature. We present an illustrative case of RCC pituitary metastasis 15 years after radical nephrectomy for primary disease and a review of the published literature. CASE DESCRIPTION: A 69-year-old female was diagnosed with a large sellar mass with suprasellar extension. The initial radiologic diagnosis was most in keeping with pituitary macroadenoma, although prominent vascular flow voids were noted. Endoscopic endonasal transsphenoidal adenectomy was challenging on account of significant intraoperative hemorrhage from an unusually vascular tumor. Pathologic examination supported a diagnosis of metastatic clear cell renal carcinoma. Literature review identified 41 cases of RCC pituitary metastasis since 1984. The mean age at time of diagnosis with pituitary metastasis was 59.5 years (range 35-81 years, 73% male). Pituitary metastasis was the initial presentation of RCC in 10 patients. The median time from RCC diagnosis to pituitary metastasis was 1 year (range 0-27 years). Surgical resection was performed for 30 patients, of which 47% reported a highly vascular tumor. CONCLUSIONS: We highlight the potential for delayed metastasis to the pituitary to masquerade as a macroadenoma. Imaging consistent with rich vascularity should bring the diagnosis of RCC metastasis into the differential and is important to note when planning surgical resection in such cases.

Giant Juvenile Ectopic Schwannoma of the Temporal Bone.

BACKGROUND: Ectopic intracranial schwannomas (those that do not arise from a named cranial nerve) are rare. They account for <2% of surgically resected central nervous system schwannomas. CASE DESCRIPTION: We report the case of a 14-year-old boy presenting with a left conductive hearing loss and temporal bone deformity. No facial or cranial nerve deficits were present. Cross-sectional imaging demonstrated a large expansile extra-axial temporal bone mass, extending into and distorting the middle cranial fossa. At surgical resection the tumor was functionally and anatomically distinct from the facial nerve or any other identifiable neural structure within the middle ear or temporal bone. Histology confirmed a World Health Organization grade 1 schwannoma. CONCLUSIONS: This is the first reported case of a giant juvenile ectopic schwannoma within the temporal bone.

Treatment Outcomes of Incidental Intracranial Meningiomas: Results from the IMPACT Cohort.

BACKGROUND: Incidental findings such as meningioma are becoming increasingly prevalent. There is no consensus on the optimal management of these patients. The aim of this study was to examine the outcomes of patients diagnosed with an incidental meningioma who were treated with surgery or radiotherapy. METHODS: Single-center retrospective cohort study of adult patients diagnosed with an incidental intracranial meningioma (2007-2015). Outcomes recorded were postintervention morbidity, histopathologic diagnosis, and treatment response. RESULTS: Out of 441 patients, 44 underwent treatment. Median age at intervention was 56.1 years (interquartile range [IQR], 49.6-66.5); patients included 35 women and 9 men. The main indication for imaging was headache (25.9%). Median meningioma volume was 4.55 cm3 (IQR, 1.91-8.61), and the commonest location was convexity (47.7%). Six patients underwent surgery at initial diagnosis. Thirty-eight had intervention (34 with surgery and 4 with radiotherapy) after a median active monitoring duration of 24 months (IQR, 11.8-42.0). Indications for treatment were radiologic progression (n = 26), symptom development (n = 6), and patient preference (n = 12). Pathology revealed World Health Organization (WHO) grade 1 meningioma in 36 patients and WHO grade 2 in 4 patients. The risk of postoperative surgical and medical morbidity requiring treatment was 25%. Early and late moderate adverse events limiting activities of daily living occurred in 28.6% of patients treated with radiotherapy. Recurrence rate after surgery was 2.5%. All meningiomas regressed or remained radiologically stable after radiotherapy. CONCLUSIONS: The morbidity after treatment of incidental intracranial meningioma is not negligible. Considering most operated tumors are WHO grade 1, treatment should be reserved for those manifesting symptoms or demonstrating substantial growth on radiologic surveillance.

A prognostic model to personalize monitoring regimes for patients with incidental asymptomatic meningiomas.

BACKGROUND: Asymptomatic meningioma is a common incidental finding with no consensus on the optimal management strategy. We aimed to develop a prognostic model to guide personalized monitoring of incidental meningioma patients. METHODS: A prognostic model of disease progression was developed in a retrospective cohort (2007-2015), defined as: symptom development, meningioma-specific mortality, meningioma growth or loss of window of curability. Secondary endpoints included non-meningioma-specific mortality and intervention. RESULTS: Included were 441 patients (459 meningiomas). Over a median of 55 months (interquartile range, 37-80), 44 patients had meningioma progression and 57 died (non-meningioma-specific). Forty-four had intervention (at presentation, n = 6; progression, n = 20; nonprogression, n = 18). Model parameters were based on statistical and clinical considerations and included: increasing meningioma volume (hazard ratio [HR] 2.17; 95% CI: 1.53-3.09), meningioma hyperintensity (HR 10.6; 95% CI: 5.39-21.0), peritumoral signal change (HR 1.58; 95% CI: 0.65-3.85), and proximity to critical neurovascular structures (HR 1.38; 95% CI: 0.74-2.56). Patients were stratified based on these imaging parameters into low-, medium- and high-risk groups and 5-year disease progression rates were 3%, 28%, and 75%, respectively. After 5 years of follow-up, the risk of disease progression plateaued in all groups. Patients with an age-adjusted Charlson comorbidity index ≥6 (eg, an 80-year-old with chronic kidney disease) were 15 times more likely to die of other causes than to receive intervention at 5 years following diagnosis, regardless of risk group. CONCLUSIONS: The model shows that there is little benefit to rigorous monitoring in low-risk and older patients with comorbidities. Risk-stratified follow-up has the potential to reduce patient anxiety and associated health care costs.