Eric Suero Molina, Christian Ewelt, Nils Warneke, Michael Schwake, Michael Müther, Stephanie Schipmann and Walter Stummer
Recent efforts to improve visualization of 5-aminolevulinic acid (5-ALA)–induced protoporphyrin IX (PPIX) fluorescence resulted in a dual-labeling technique, combining it with fluorescein sodium in a prototype setup. Fluorescein identifies regions with blood-brain barrier breakdown in gliomas. However, normally perfused and edematous brain fluoresces unselectively, with strong background enhancement. The aim of this study was to test the feasibility of a novel, integrated filter combination using porphyrins for selective tumor identification and fluorescein for background enhancement.
A microscope with a novel built-in filter system (YB 475) for visualizing both fluorescein and 5-ALA–induced porphyrins was used. Resection limits were identified with the conventional BLUE 400 filter system. Six patients harboring contrast ring-enhancing lesions were analyzed.
The complete surgical field could now be illuminated. Fluorescein was helpful for improving background visualization, and enhancing dura, edematous tissue, and cortex. Overlapping regions with both fluorophores harbored merged orange fluorescence. PPIX fluorescence was better visualized, even in areas beyond a normal working distance of approximately 25 cm, where the BLUE 400 filters recognized no or weak fluorescence.
The novel filter system improved general tissue brightness and background visualization, enhancing fluorescence-guided tumor resection. Furthermore, it appears promising from a scientific perspective, enabling the simultaneous and direct observation of areas with blood-brain barrier breakdown and PPIX fluorescence.
Eric Suero Molina, Stephanie Schipmann, Isabelle Mueller, Johannes Wölfer, Christian Ewelt, Matthias Maas, Benjamin Brokinkel and Walter Stummer
Awake craniotomies have become a feasible tool over time to treat brain tumors located in eloquent regions. Different techniques have been applied in neurooncology centers. Both “asleep-awake-asleep” (asleep) and “conscious sedation” were used subsequently at the authors’ neurosurgical department. Since 2013, the authors have only performed conscious sedation surgeries, predominantly using the α2-receptor agonist dexmedetomidine as the anesthetic drug. The aim of this study was to compare both mentioned techniques and evaluate the clinical use of dexmedetomidine in the setting of awake craniotomies for glioma surgery.
The authors retrospectively analyzed patients who underwent operations either under the asleep condition using propofol-remifentanil or under conscious sedation conditions using dexmedetomidine infusions. In the asleep group patients were intubated with a laryngeal mask and extubated for the assessment period. Adverse events, as well as applied drugs with doses and frequency of usage, were recorded.
From 224 awake surgeries between 2009 and 2015, 180 were performed for the resection of gliomas and included in the study. In the conscious sedation group (n = 75) significantly fewer opiates (p < 0.001) and vasoactive (p < 0.001) and antihypertensive (p < 0.001) drugs were used in comparison with the asleep group (n = 105). Furthermore, the postoperative length of stay (p < 0.001) and the surgical duration (p < 0.001) were significantly lower in the conscious sedation group.
Use of dexmedetomidine creates excellent conditions for awake surgeries. It sedates moderately and acts as an anxiolytic. Thus, after ceasing infusion it enables quick and reliable clinical neurological assessment of patients. This might lead to reducing the amount of administered antihypertensive and vasoactive drugs as well as the length of hospitalization, while likely ensuring more rapid surgery.
Michael Schwake, Stephanie Schipmann, Michael Müther, Louise Stögbauer, Uta Hanning, Peter B. Sporns, Christian Ewelt, Rainer Dziewas, Jens Minnerup, Markus Holling and Walter Stummer
Decompressive craniectomies (DCs) are performed on patients suffering large cerebral infarctions. The efficacy of this procedure has been demonstrated in several trials. In some cases, however, this procedure alone is not sufficient and patients still suffer refractory elevations of intracranial pressure (ICP). The goal of this study was to determine whether resection of infarcted tissue, termed strokectomy, performed as a second-look procedure after DC, improves outcome in selected cases.
The authors retrospectively evaluated data of patients who underwent a DC due to a cerebral infarction at their institution from 2009 to 2016, including patients who underwent a strokectomy procedure after DC. Clinical records, imaging data, outcome scores, and neurological symptoms were analyzed, and clinical outcomes and mortality rates in the strokectomy group were compared to those for similar patients in recently published randomized controlled trials.
Of 198 patients who underwent DC due to cerebral infarction, 12 patients underwent strokectomy as a second surgical procedure, with a median National Institutes of Health Stroke Scale (NIHSS) score of 19 for patients with versus 16 for those without secondary strokectomy (p = 0.029). Either refractory increases of ICP > 20 mm Hg or dilated pupils in addition to herniation visible on CT images were triggers for strokectomy surgery. Ten of 12 (83%) patients had infarctions in more than one territory (p < 0.001). After 12 months, 43% of patients had a good outcome according to the modified Rankin Scale (mRS) score (≤ 3). In the subgroup of patients suffering infarctions in more than one vascular territory, functional outcome after 12 months was better (mRS ≤ 3 in 40% of patients in comparison to 9%; p = 0.027). A 1:3 case-control analysis matched to age, side of infarction, sex, and vascular territory confirmed these results (mRS ≤ 3, 42% in comparison to 11%; p = 0.032). Age, NIHSS score on admission, and number of vascular territories involved were identified as risk factors in multivariate analysis (p < 0.05). Patients in the strokectomy group had more infections (p < 0.001). According to these results, the authors developed a scale (Münster Stroke Score, 0–6 points) to predict whether patients might benefit from additional strokectomy. Receiver-operating characteristic (ROC) curve analysis revealed an area under the curve (AUC) of 0.86 (p < 0.001). The authors recommend a Münster Stroke Score of ≥ 3 as a cutoff, with a sensitivity of 92% and specificity of 66%, for predicting benefit from strokectomy.
In this study in comparison to former studies, mortality rates were lower and clinical outcome was comparable to that of previously published trials regarding large cerebral infarctions. Second surgery including strokectomy may help achieve better outcomes, especially in cases of infarction of more than one vascular territory.