Intraoperative detection of blood vessels with an imaging needle during neurosurgery in humans

Intracranial hemorrhage can be a devastating complication associated with needle biopsies of the brain. Hemorrhage can occur to vessels located adjacent to the biopsy needle as tissue is aspirated into the needle and removed. No intraoperative technology exists to reliably identify blood vessels that are at risk of damage. To address this problem, we developed an “imaging needle” that can visualize nearby blood vessels in real time. The imaging needle contains a miniaturized optical coherence tomography probe that allows differentiation of blood flow and tissue. In 11 patients, we were able to intraoperatively detect blood vessels (diameter, \u3e500 μm) with a sensitivity of 91.2% and a specificity of 97.7%. This is the first reported use of an optical coherence tomography needle probe in human brain in vivo. These results suggest that imaging needles may serve as a valuable tool in a range of neurosurgical needle interventions

Neurosurgical Applications of Magnetic Resonance Diffusion Tensor Imaging

Magnetic Resonance (MR) Diffusion Tensor Imaging (DTI) is a rapidly evolving technology that enables the visualization of neural fiber bundles, or white matter (WM) tracts. There are numerous neurosurgical applications for MR DTI including: (1) Tumor grading and staging; (2) Pre-surgical planning (determination of resectability, determination of surgical approach, identification of WM tracts at risk); (3) Intraoperative navigation (tumor resection that spares WM damage, epilepsy resection that spares WM damage, accurate location of deep brain stimulation structures); (4) Post-operative assessment and monitoring (identification of WM damage, identification of tumor recurrence). Limitations of MR DTI include difficulty tracking small and crossing WM tracts, lack of standardized data acquisition and post-processing techniques, and practical equipment, software, and timing considerations. Overall, MR DTI is a useful tool for planning, performing, and following neurosurgical procedures, and has the potential to significantly improve patient care. Technological improvements and increased familiarity with DTI among clinicians are next steps

Full Issue: Volume 13, Issue 1 - Winter 2018

Full Issue: Volume 13, Issue 1 - Winter 201

Neurosurgery in Obsessive Compulsive Disorder:From targets to treatment to tracts and back again

People with obsessive compulsive disorder (OCD) suffer from obsessive thoughts and/or behavior, with a constant presence that can hardly be ignored. A range of interventions is effective in the management of OCD including behavioral therapy, cognitive therapy and cognitive behavioral therapy (CBT). In addition, a large body of evidence advocate on the use of selective serotonin reuptake inhibitors (SSRIs) and clomipramine, a tricyclic antidepressant, in the treatment of OCD, often used in combination with CBT. However, 40-60% of patients remain treatment-refractory, defined as a less than 25% reduction in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score. This scale is used to determine the severity of the disorder. The resistance of such a big amount of patients to therapy may urge the need for alternative treatment strategies, such as deep brain stimulation (DBS) of subcortical structures or gamma knife ventral capsulotomy (GVC), a noninvasive procedure using gamma rays to destroy certain brain tissues. The first part of this thesis aimed at identifying fiber bundles associated with clinical response to DBS or GVC. OCD patients consistently underperform across multiple cognitive domains. The second part of this thesis was focused on the neuropsychological outcome of OCD DBS in order to identify a cognitive pattern associated with a good outcome or that would (in part) help explain the functional mechanism of OCD-DBS. The third part focused on several postoperative aspects of (OCD)-DBS patients including surgical and hardware related adverse events of DBS and reviewing the effectiveness, timing and procedural aspects of CBT after DBS with the aim to provide clinical recommendations

Music and musicality in brain surgery:The effect on delirium and language

Delirium is a neuropsychiatric clinical syndrome with overlapping symptoms withthe neurologic primary disease. This is why delirium is such a difficult and underexposedtopic in neurosurgical literature. Delirium is a complication which mightaffect recovery after brain surgery, hence we describe in Chapter 2 a systematicreview which focuses on how delirium is defined in the neurosurgical literature.We included twenty-four studies (5589 patients) and found no validation studiesof screening instruments in neurosurgical papers. Delirium screening instruments,validated in other cohorts, were used in 70% of the studies, consisting of theConfusion Assessment Method (- Intensive Care Unit) (45%), Delirium ObservationScreening Scale (5%), Intensive Care Delirium Screening Checklist (10%), Neelonand Champagne Confusion Scale (5%), and Nursing Delirium Screening Scale (5%).Incidence of post-operative delirium after intracranial surgery was 19%, ranging from12 – 26% caused by variation in clinical features and delirium assessment methods.Our review highlighted the need of future research on delirium in neurosurgery,which should focus on optimizing diagnosis, and assessing prognostic significanceand management.It is unclear what the impact of delirium is on the recovery after brain surgery,as delirium is often a self-limiting and temporary complication. In Chapter 3 wetherefore investigated the impact of delirium, by means of incidence and healthoutcomes, and identified independent risk factors by including 2901 intracranialsurgical procedures. We found that delirium was present in 19.4% with an averageonset (mean/SD) within 2.62/1.22 days and associated with more Intensive CareUnit (ICU) admissions and more discharge towards residential care. These numbersconfirm the impact of delirium with its incidence rates, which were in line with ourprevious systematic review, and significant health-related outcomes. We identifiedseveral independent non-modifiable risk factors such as age, pre-existing memoryproblems, emergency operations, and modifiable risk factors such as low preoperativepotassium and opioid and dexamethasone administration, which shed lighton the pathophysiologic mechanisms of POD in this cohort and could be targetedfor future intervention studies.10As listening to recorded music has been proven to lower delirium-eliciting factors inthe surgical population, such as pain, we were interested in the size of analgesic effectand its underlying mechanism before applying this into our clinical setting. In Chapter4 we describe the results of a two-armed experimental randomized controlled trial inwhich 70 participants received increasing electric stimuli through their non-dominantindex finger. This study was conducted within a unique pain model as participantswere blinded for the outcome. Participants in the music group received a 20-minutemusic intervention and participants in the control group a 20-minute resting period.Although the effect of the music intervention on pain endurance was not statisticallysignificant in our intention-to-treat analysis (p = 0.482, CI -0.85; 1.79), the subgroupanalyses revealed an increase in pain endurance in the music group after correcting fortechnical uncertainties (p = 0.013, CI 0.35; 2.85). This effect on pain endurance couldbe attributed to increased parasympathetic activation, as an increased Heart RateVariability (HRV) was observed in the music vs. the control group (p=0.008;0.032).As our prior chapters increased our knowledge on the significance of delirium on thepost-operative recovery after brain surgery and the possible beneficial effects of music,we decided to design a randomized controlled trial. In Chapter 5 we describe theprotocol and in Chapter 6 we describe the results of this single-centered randomizedcontrolled trial. In this trial we included 189 patients undergoing craniotomy andcompared the effects of music administered before, during and after craniotomy withstandard of clinical care. The primary endpoint delirium was assessed by the deliriumobservation screening scale (DOSS) and confirmed by a psychiatrist accordingto DSM-5 criteria. A variety of secondary outcomes were assessed to substantiatethe effects of music on delirium and its clinical implications. Our results supportthe efficacy of music in preventing delirium after craniotomy, as found with DOSS(OR:0.49, p=0.048) but not after DSM-5 confirmation (OR:0.47, p=0.342). Thispossible beneficial effect is substantiated by the effect of music on pre-operativeautonomic tone, measured with HRV (p=0.021;0.025), and depth of anesthesia(p=&lt;0.001;0.022). Our results fit well within the current literature and support theimplementation of music for the prevention of delirium within the neurosurgicalpopulation. However, delirium screening tools should be validated and the long-termimplications should be evaluated after craniotomy to assess the true impact of musicafter brain surgery.Musicality and language in awake brain surgeryIn the second part of this thesis, the focus swifts towards maintaining musicality andlanguage functions around awake craniotomy. Intra-operative mapping of languagedoes not ensure complete maintenance which mostly deteriorates after tumor resection.Most patients recover to their baseline whereas other remain to suffer from aphasiaaffecting their quality of life. The level of musical training might affect the speed andextend of postoperative language recovery, as increased white matter connectivity inthe corpus callosum is described in musicians compared to non-musicians. Hence,in Chapter 7 we evaluate the effect of musicality on language recovery after awakeglioma surgery in a cohort study of forty-six patients. We divided the patients intothree groups based on the musicality and compared the language scores between thesegroups. With the first study on this topic, we support that musicality protects againstlanguage decline after awake glioma surgery, as a trend towards less deterioration oflanguage was observed within the first three months on the phonological domain (p= 0.04). This seemed plausible as phonology shares a common hierarchical structurebetween language and singing. Moreover, our results support the hypothesis ofmusicality induced contralateral compensation in the (sub-) acute phase through thecorpus callosum as the largest difference of size was found in the anterior corpuscallosum in non- musicians compared to trained musicians (p = 0.02).In Chapter 8 we addressed musicality as a sole brain function and whether it canbe protected during awake craniotomy in a systematic review consisting of tenstudies and fourteen patients. Isolated music disruption, defined as disruption duringmusic tasks with intact language/speech and/or motor functions, was identified intwo patients in the right superior temporal gyrus, one patient in the right and onepatient in the left middle frontal gyrus and one patient in the left medial temporalgyrus. Pre-operative functional MRI confirmed these localizations in three patients.Assessment of post-operative musical function, only conducted in seven patients bymeans of standardized (57%) and non-standardized (43%) tools, report no loss ofmusical function. With these results we concluded that mapping music is feasibleduring awake craniotomy. Moreover, we identified certain brain regions relevant formusic production and detected no decline during follow-up, suggesting an addedvalue of mapping musicality during awake craniotomy. A systematic approach to mapmusicality should be implemented, to improve current knowledge on the added valueof mapping musicality during awake craniotomy.<br/