Anaesthetic Management of Left Temporal Glioma Undergoing Awake Craniotomy

For an awake craniotomy, a 49 year old (ASA 2), 78 kg woman with type II DM was given regional anaesthesia (scalp block) with monitored anaesthesia care (MAC). She had a headache, which was primarily caused by a left temporal glioma. She was very apprehensive about having this procedure done while she was awake. Fentanyl and Dexmedetomidine infusions in combination with scalp block initially provided adequate operating conditions. Because the patient needed to be fully awake, alert and cooperative during the language and motor mapping, all sedation was turned off. Patient was cooperative and obeyed commands during motor and language mapping as well as during tumour excision. Patient underwent complete excision of tumour without any postoperative neurological deficit. The success of the awake craniotomy is dependent on the patient cooperation, anaesthesiologist's experience, adequate intraoperative analgesia coverage, careful sedation titration, and meticulous planning.

Novel Use of Stimulating Fence-Post Technique for Functional Mapping of Subcortical White Matter During Tumor Resection: A Technical Case Series

Background Maximal safe resection remains a key principle in infiltrating glioma management. Stimulation mapping is a key adjunct for minimizing functional morbidity while “fence-post” procedures use catheters or dye to mark the tumor border at the start of the procedure prior to brain shift. Objective To report a novel technique using stereotactically placed electrodes to guide tumor resection near critical descending subcortical fibers. Methods Navigated electrodes were placed prior to tumor resection along the deep margin bordering presumed eloquent tracts. Stimulation was administered through these depth electrodes for subcortical motor and language mapping. Results Twelve patients were included in this preliminary technical report. Seven patients (7/12, 58%) were in asleep cases, while the other 5 cases (5/12, 42%) were performed awake. Mapping of motor fibers was performed in 8 cases, and language mapping was done in 1 case. In 3 cases, both motor and language mapping were performed using the same depth electrode spanning corticospinal tract and the arcuate fasciculus. Conclusion Stereotactic depth electrode placement coupled with stimulation mapping of white matter tracts can be used concomitantly to demarcate the border between deep tumor margins and eloquent brain, thus helping to maximize extent of resection while minimizing functional morbidity.

Accuracy analysis of fMRI and MEG activations determined by intraoperative mapping

OBJECTIVEBy looking at how the accuracy of preoperative brain mapping methods vary according to differences in the distance from the activation clusters used for the analysis, the present study aimed to elucidate how preoperative functional neuroimaging may be used in such a way that maximizes the mapping accuracy.METHODSThe eloquent function of 19 patients with a brain tumor or cavernoma was mapped prior to resection with both functional MRI (fMRI) and magnetoencephalography (MEG). The mapping results were then validated using direct cortical stimulation mapping performed immediately after craniotomy and prior to resection. The subset of patients with equivalent MEG and fMRI tasks performed for motor (n = 14) and language (n = 12) were evaluated as both individual and combined predictions. Furthermore, the distance resulting in the maximum accuracy, as evaluated by the J statistic, was determined by plotting the sensitivities and specificities against a linearly increasing distance threshold.RESULTSfMRI showed a maximum mapping accuracy at 5 mm for both motor and language mapping. MEG showed a maximum mapping accuracy at 40 mm for motor and 15 mm for language mapping. At the standard 10-mm distance used in the literature, MEG showed a greater specificity than fMRI for both motor and language mapping but a lower sensitivity for motor mapping. Combining MEG and fMRI showed a maximum accuracy at 15 mm and 5 mm—MEG and fMRI distances, respectively—for motor mapping and at a 10-mm distance for both MEG and fMRI for language mapping. For motor mapping, combining MEG and fMRI at the optimal distances resulted in a greater accuracy than the maximum accuracy of the individual predictions.CONCLUSIONSThis study demonstrates that the accuracy of language and motor mapping for both fMRI and MEG is heavily dependent on the distance threshold used in the analysis. Furthermore, combining MEG and fMRI showed the potential for increased motor mapping accuracy compared to when using the modalities separately.Clinical trial registration no.: NCT01535430 (clinicaltrials.gov)

Patient Reported Experience Measures in navigated Transcranial Magnetic Stimulation

Introduction Navigated Transcranial Magnetic Stimulation (nTMS) is a non-invasive adjunct used in surgical planning for lesions in eloquent brain. However, its patient tolerability and effect on their overall healthcare experience is still unknown. To our knowledge, there is no other literature available evaluating patient experience with nTMS. Methods A single-institution prospective cohort study carried out between February 2018 and December 2018 at King’s College Hospital. All patients were supplied with a PREMs-TMS questionnaire to evaluate the different domains of the nTMS experience. Results Feedback was obtained from 50 patients. 26% of patients underwent motor mapping (MM), whilst 74% underwent both motor and language mapping (MLM). The former group reported a better overall experience (p=0.020). The mean exam duration was 103.3±5.1 min (MM 85.8±6.1 min; MLM 106.9±5.9 min). The whole experience of nTMS received positive feedback (94%), particularly with confidence in the staff (95%). Unsurprisingly, the exam domain received a poorer rating (70% as good) with significant anxiety and pain reported in 26% and 24% of patients respectively. None of the studied variables influenced the way patients rated the overall experience of nTMS (p>0.05). Conclusions nTMS is a non-invasive investigative tool, which allows patients to better understand their condition and symptoms related to their lesion. Serial assessment and feedback using a PREM tool, can only improve and enhance this experience. Departmental collaboration may be useful in comparing patient experience with nTMS in different centres.