Mini Screws for Improving Accuracy in Navigation-assisted Spine Surgery.

STUDY DESIGN: Presentation of a surgical technique with accompanying video (Supplemental Digital Content 1, http://links.lww.com/CLINSPINE/A67) of an illustrative case. OBJECTIVE: The objective of this study was to present a helpful and easy-to-implement technique for improving initial referencing accuracy, as well as rereferencing accuracy in cases of multilevel instrumentation or in cases of dislocation of the reference array. SUMMARY OF BACKGROUND DATA: Navigation-assisted spine surgery has become standard of care in most hospitals performing complex spine interventions. Although short-segment instrumentations are fairly straight-forward with current hardware and software solutions, obtaining ideal accuracies and troubleshooting reference array disruptions remain challenging. METHODS: A surgical technique is presented as a step-by-step guide using intraoperative videos and photographs as well as imaging data in an illustrative case of thoracic hemivertebra resection and dorsal instrumentation. TECHNIQUE/RESULTS: After skin incision is performed at the index level, posterior soft tissue preparation is performed. Before firmly attaching the reference array to a spinous process we then insert a minimum of four 5 mm mini screws at any bony structure within the exposure. Then an intraoperative navigation scan (3-dimensional computed tomography or x-ray) is obtained, and initial referencing is performed using the previously inserted mini screws as landmarks. This yields mean accuracies of 1 mm or lower and is easily verifiable by placing the navigation probe on a mini screw head. This action can be swiftly repeated at any time to prevent reduced accuracy because of insertion forces applied during pedicle screw placement. In addition, this allows for easy rereferencing in cases of disruption or complete removal of the navigation array, eliminating the need to perform additional computed tomography or x-ray scans during the procedure. CONCLUSIONS: The technique presented allows for rapid and highly accurate initial referencing and can be used in all cases of navigation-assisted spine surgery. It also allows for hassle-free rereferencing in cases of disruption or accidental removal of the reference array.

A New Approach for Photorealistic Visualization of Rendered Computed Tomography Images.

OBJECTIVE: Classical single-colored or multicolored 3-dimensional (3D) visualization of sectional images lacked in being realistic and revealed limited anatomical discrimination. Recently, a new technique called cinematic volume rendering for 3D reconstruction of computed tomography has been developed. The aim of this study was to analyze this new visualization algorithm from a technical perspective and to investigate potential benefits for neurosurgical applications. METHODS: A standard test in computer graphics called Cornell Box was adapted and applied for reproducibility of light effects in cinematic rendering opposed to classic rendering methods. Simulation of distinct camera effects such as variable apertures, exposition time, optics, and surface refinements are presented in a human skull, respectively. Postprocessing capabilities allow for immediate clinical use. RESULTS: This volume-rendering technique generates cadaver-like 3D reconstructions. By considering complex interactions between a scanned object and dynamic light patterns, a cinematic illumination of a 3D surface reconstruction can be achieved. A spinal tumor case and a complex intracranial carotid artery aneurysm are presented, comparing all available rendering techniques. Cinematic rendering results in greater spatial discrimination of neighboring anatomical structures. CONCLUSIONS: This technical and clinical description focuses on the neurosurgical relevance of a new rendering technique. Considering the improved image impression of cinematic rendering and viewers' perception, it seems likely that the technique will gain wide acceptance in the clinical routine.

Risk Factors and Management of Incidental Durotomy in Lumbar Interbody Fusion Surgery.

STUDY DESIGN: This is a retrospective study analysis. OBJECTIVE: In this retrospective study we evaluated risk factors for incidental durotomy and its impact on the postoperative course. SUMMARY OF BACKGROUND DATA: Lumbar interbody fusion (LIF) is increasingly applied for the treatment of degenerative instability. A known complication is incidental durotomy. MATERIALS AND METHODS: A cohort of 541 patients who underwent primary LIF surgery between 2005 and 2015 was analyzed. Previous lumbar surgery, age, surgeon's experience, intraoperative use of a microscope, and the number of operated levels were assessed and the risk for incidental durotomy was estimated using the Log-likelihood test and Wald test, respectively. The association of incidental durotomy and outcome parameters was analyzed using the quantile regression model. RESULTS: In 77 (14.2%) patients intraoperative cerebrospinal fluid (CSF) fistula was observed. Previous lumbar surgery (P<0.001), number of operated levels (P=0.03), and surgeon's experience (P=0.01) were significantly associated with incidental durotomy. Incidental durotomy was significantly associated with a prolonged bed rest (P<0.001), hospital stay (P=0.041), and an increased use of postoperative antibiotics (P<0.001). Eleven of 77 patients with incidental durotomy (14.3%) developed postoperative CSF fistula of whom 10 (91%) needed revision surgery for dural repair. CONCLUSIONS: We could identify important risk factors for incidental durotomy in LIF surgery. In patients who had undergone previous lumbar surgery and those with multilevel disease particular precaution is required. Furthermore, we were able to verify the morbidity associated with CSF fistula as shown by increased immobilization and follow-up surgeries for postoperative CSF fistula which emphasizes the importance to develop strategies to minimize the risk for incidental durotomy.

GAVCA Study: Randomized, Multicenter Trial to Evaluate the Quality of Ventricular Catheter Placement with a Mobile Health Assisted Guidance Technique.

BACKGROUND: Freehand ventricular catheter placement may represent limited accuracy for the surgeon's intent to achieve primary optimal catheter position. OBJECTIVE: To investigate the accuracy of a ventricular catheter guide assisted by a simple mobile health application (mhealth app) in a multicenter, randomized, controlled, simple blinded study (GAVCA study). METHODS: In total, 139 eligible patients were enrolled in 9 centers. Catheter placement was evaluated by 3 different components: number of ventricular cannulation attempts, a grading scale, and the anatomical position of the catheter tip. The primary endpoint was the rate of primary cannulation of grade I catheter position in the ipsilateral ventricle. The secondary endpoints were rate of intraventricular position of the catheter's perforations, early ventricular catheter failure, and complications. RESULTS: The primary endpoint was reached in 70% of the guided group vs 56.5% (freehand group; odds ratio 1.79, 95% confidence interval 0.89-3.61). The primary successful puncture rate was 100% vs 91.3% (P = .012). Catheter perforations were located completely inside the ventricle in 81.4% (guided group) and 65.2% (freehand group; odds ratio 2.34, 95% confidence interval 1.07-5.1). No differences occurred in early ventricular catheter failure, complication rate, duration of surgery, or hospital stay. CONCLUSION: The guided ventricular catheter application proved to be a safe and simple method. The primary endpoint revealed a nonsignificant improvement of optimal catheter placement among the groups. Long-term follow-up is necessary in order to evaluate differences in catheter survival among shunted patients.

Development and Validation of an Automatic Segmentation Algorithm for Quantification of Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: ABC/2 is still widely accepted for volume estimations in spontaneous intracerebral hemorrhage (ICH) despite known limitations, which potentially accounts for controversial outcome-study results. The aim of this study was to establish and validate an automatic segmentation algorithm, allowing for quick and accurate quantification of ICH. METHODS: A segmentation algorithm implementing first- and second-order statistics, texture, and threshold features was trained on manual segmentations with a random-forest methodology. Quantitative data of the algorithm, manual segmentations, and ABC/2 were evaluated for agreement in a study sample (n=28) and validated in an independent sample not used for algorithm training (n=30). RESULTS: ABC/2 volumes were significantly larger compared with either manual or algorithm values, whereas no significant differences were found between the latter (P<0.0001; Friedman+Dunn's multiple comparison). Algorithm agreement with the manual reference was strong (concordance correlation coefficient 0.95 [lower 95% confidence interval 0.91]) and superior to ABC/2 (concordance correlation coefficient 0.77 [95% confidence interval 0.64]). Validation confirmed agreement in an independent sample (algorithm concordance correlation coefficient 0.99 [95% confidence interval 0.98], ABC/2 concordance correlation coefficient 0.82 [95% confidence interval 0.72]). The algorithm was closer to respective manual segmentations than ABC/2 in 52/58 cases (89.7%). CONCLUSIONS: An automatic segmentation algorithm for volumetric analysis of spontaneous ICH was developed and validated in this study. Algorithm measurements showed strong agreement with manual segmentations, whereas ABC/2 exhibited its limitations, yielding inaccurate overestimations of ICH volume. The refined, yet time-efficient, quantification of ICH by the algorithm may facilitate evaluation of clot volume as an outcome predictor and trigger for surgical interventions in the clinical setting.

Evaluation of a New Brain Tissue Probe for Cerebral Blood Flow Monitoring in an Experimental Pig Model.

BACKGROUND: Bedside monitoring of cerebral blood flow (CBF) may provide new insights into the pathophysiology of brain injury, allow early detection of secondary ischemia, and help guide therapy. OBJECTIVE: To evaluate a new brain tissue probe for serial CBF monitoring using near-infrared spectroscopy and indocyanine green dye dilution (NeMo Probe) compared with the existing thermal diffusion probe (QFlow 500 Probe). METHODS: In 7 pigs, the NeMo Probe and QFlow 500 Probe were inserted into the subcortical white matter. Parallel measurements were recorded during (1) baseline, (2) hypotension, (3) hypertension, and (4) hyperventilation. Thereafter, protocol points 1 through 4 were repeated once. The Spearman correlation (rs), Bland-Altman plot, concordance rate, and coefficient of variation were used for statistical analysis. RESULTS: There was poor agreement between 56 pairs of absolute CBF values (rs = 0.52, P < .001). The mean bias was 10.7 mL·100 g·min with limits of agreement of -33.0 to 54.3 mL·100 g·min. The analysis of 49 pairs of changes in CBF showed a good correlation (rs = 0.83, P < .001), and the concordance rate was 93.3%. The coefficient of variation from repeated measurements under comparable physiological conditions was 51.6% for the QFlow 500 Probe and 12.9% for the NeMo Probe. CONCLUSION: Absolute CBF values obtained with the NeMo Probe and QFlow 500 Probe cannot be interpreted as equivalent. However, the NeMo Probe provides acceptable trending ability and reproducibility from repeated measurements, whereas the reproducibility of the QFlow 500 Probe was poor. Future clinical studies are warranted to evaluate the NeMo Probe in the setting of acute brain injury. ABBREVIATIONS: CBF, cerebral blood flowCBV, cerebral blood volumeICG, indocyanine greenICP, intracranial pressureMAP, mean arterial pressuremttICG, mean transit time of indocyanine greenNIRS, near-infrared spectroscopy.

Evaluation of a New Brain Tissue Probe for Intracranial Pressure, Temperature, and Cerebral Blood Flow Monitoring in Patients with Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: To evaluate an intraparenchymal probe for intracranial pressure (ICP) and temperature (TEMP) monitoring as well as determination of cerebral hemodynamics using a near-infrared spectroscopy (NIRS) and indocyanine green (ICG) dye dilution method (NIRS-ICP probe). METHODS: The NIRS-ICP probe was applied after aneurysmal subarachnoid hemorrhage if multimodal monitoring was established due to poor neurological condition. ICP and TEMP values were obtained from ventricular catheters and systemic temperature sensors. Repeated NIRS-ICG measurements (2 injections within 30 min) were performed daily for determination of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time of ICG (mttICG). Secondary neurologic dysfunction was defined as brain tissue oxygen tension <20 mmHg and/or lactate/pyruvate ratio >35 obtained from cerebral probing. RESULTS: A total of 128 NIRS-ICG measurements were performed in ten patients. The correlation coefficients between ICP and TEMP values obtained with the NIRS-ICP probe and values from routine monitoring were r = 0.72 and r = 0.96, respectively. The mean values were 30.3 ± 13.6 ml/100 g/min for CBF, 3.3 ± 1.2 ml/100 g for CBV, and 6.8 ± 1.6 s for mttICG. The coefficients of variation from repeated NIRS-ICG measurements were 10.9 % for CBF, 11.7 % for CBV, and 3.8 % for mttICG. The sensitivity for detection of secondary neurologic dysfunction was 85 % and the specificity 83 % using a CBF-threshold of 25 ml/100 g/min. CONCLUSION: Multimodal monitoring using the NIRS-ICP probe is feasible with high reproducibility of measurement values and the ability to detect secondary neurologic dysfunction. No safety concerns exist for the routine clinical use of the NIRS-ICP probe.

Visualization of pressure related vessel compression in the perihemorrhagic zone during endoscopic ICH evacuation.

OBJECTIVES: The existence of perihemorrhagic ischemia in intracerebral hemorrhage (ICH) has been subject to intense debate. In contrast, the concept of reduced cerebral blood flow (CBF) in the perihemorrhagic zone (PHZ) is widely accepted. This report aims to demonstrate preliminary experience with endoscopic visualization of perihemorrhagic vessel compression in patients with ICH. PATIENTS AND METHODS: Endoscopic findings in the PHZ during minimally invasive hematoma evacuation in six patients with basal ganglia ICH are described. 3D-Neuronavigation for exact real-time orientation and a translucent working channel for tissue visibility are used. RESULTS: While entering the hematoma with the endoscope, the same distinct areas are illustrated in five patients: In the cortical entry zone, uncompressed vessels are present. In the subcortical white matter, vessel quantity shows its physiological rarification. In perihemorrhagic white matter adjacent to the ICH however, vessels appear to be almost completely absent. After hematoma-evacuation, the lack of vessels in the PHZ vanishes and in contrast, correlates of hyperperfusion are observed. Occurrence of these findings does not show correlation with clinical or radiological parameters. However, the only patient without vessel compression in the PHZ had the best neurological outcome in this small case series. CONCLUSION: We present visual correlates of mechanical vasoconstriction due to tissue compression in the PHZ of patients with basal ganglia ICH. Removal of the hematoma leads to visible reperfusion of the PHZ. These findings may help to understand the perihemorrhagic pathophysiology associated with focal reduction of cerebral blood flow and possibly ischemic changes in ICH.

Against the Odds: Massive Lumbar Intradural Disk Herniation in the Elderly.

Study Design Case report. Objective Presentation of an unusual case of an elderly patient with massive intradural disk herniation at the L2-L3 level. Methods Clinical and imaging data are presented after obtaining informed consent from the patient. Results A 90-year-old man suffering from sudden-onset neurogenic bladder dysfunction and lower back pain but no further neurologic deficits initially presented with magnetic resonance imaging and laboratory values suggestive of an intraspinal infection. However, intraoperative inspection proved the unexpected finding of a large intradural lumbar disk herniation at the L2-L3 level. Conclusions Lumbar soft disk herniation to the intradural space is a rare event and has never been described in a patient over the age of 75. This case of a 90-year-old man with acute-onset bladder dysfunction underlines the necessity to consider this as a differential diagnosis in the case of a newly diagnosed intradural mass.

Intracranial haemorrhage in patients treated with direct oral anticoagulants.

INTRODUCTION: Direct oral anticoagulants (DOAC) are increasingly used for the prevention and treatment of thromboembolic events. However, only little evidence is available regarding the management of patients who are treated with DOAC and present with potentially life-threatening intracranial haemorrhage. Herein, we describe our experience with respective patients treated at our institution. METHODS: We retrospectively analysed all consecutive patients with DOAC intake and intracranial haemorrhage treated at our institution from 09/2011 to 03/2015. Patient characteristics were analysed with specific focus on results of laboratory studies, treatment modalities and patient outcomes. Findings were compared between survivors (SV) and non-survivors (NSV) on day 30 after admission. RESULTS: A total of 55 patients were identified. The 30-day mortality rate in this patient cohort was 20.0%. Neurosurgical procedures were carried out in 37 patients (67%). Median values of international normalized ratio (INR) did not differ significantly between SV (1.11) and NSV (1.09). Renal function was significantly lower in NSV (median serum creatinine: 115µmol/l) than in SV (median serum creatinine: 69µmol/l; p<0.05) and all patients with serum creatinine levels >125µmol/l died during in-hospital treatment. Pro-haemostatic therapy with prothrombin complex concentrates (PCC) had no effect on INR in repeated measurements. CONCLUSION: Our experience demonstrates that successful neurosurgical management of patients with intracranial haemorrhage and DOAC intake is feasible. However, drastic deterioration was observed in some patients, particularly when impaired renal function was present. The role of pro-haemostatic therapy with PCC is unclear. These findings underscore the urgent need of improving treatment modalities for these patients.

Is microdialysis useful for early detection of acute rejection after kidney transplantation?

INTRODUCTION: Acute rejection following kidney transplantation (KTx) is still one of the challenging complications leading to chronic allograft failure. The aim of this study was to investigate the role of microdialysis (MD) in the early detection of acute graft rejection factor following KTx in porcine model. METHODS: Sixteen pigs were randomized after KTx into case (n = 8, without immunosuppressant) and control groups (n = 8, with immunosuppressant). The rejection diagnosis in our groups was confirmed by histopathological evidences as "acute borderline rejection". Using MD, we monitored the interstitial concentrations of glucose, lactate, pyruvate, glutamate and glycerol in the transplanted grafts after reperfusion. RESULTS: In the early post-reperfusion phase the lactate level in our case group was significantly higher comparing to the control group and remained in higher levels until the end of monitoring. The lactate to pyruvate ratio showed a considerable increase in the case group during the post-reperfusion phase. The other metabolites (glucose, glycerol, glutamate) were nearly at the same levels at the end of our monitoring in both study groups. CONCLUSION: The increase in lactate and lactate to pyruvate ratios seems to be an indicator for early detection of acute rejection after KTx. Therefore, MD as a minimally invasive measurement tool may help to identify the need to immunosuppression adjustment in the early KTx phase before the clinical manifestation of the rejection.

Minimally invasive endoscopic surgery for treatment of spontaneous intracerebral haematomas.

Spontaneous intracerebral haemorrhage (ICH) is a devastating disease with a mortality rate of more than 40 % and a high morbidity rate with 10-15 % of survivors remaining fully dependent [11]. The role of surgical treatment of ICH remains a matter of controversy and ongoing investigation. Advances in neurosurgical techniques such as endoscopy and neuronavigation have been established in various fields of neurosurgery. Results of reported case series have suggested that some patients with ICH may benefit from haematoma evacuation through minimally invasive endoscopic procedures. In this article, we focus on the pathophysiologic rationales behind minimally invasive haematoma evacuation through endoscopic surgery and provide an overview of technical developments and reported patient series. In addition, the modalities of the surgical procedure at the authors' institution are described. Controlled clinical trials are needed to evaluate the full potential and limitations of this promising technique.

Perihemorrhagic ischemia occurs in a volume-dependent manner as assessed by multimodal cerebral monitoring in a porcine model of intracerebral hemorrhage.

BACKGROUND: Changes in the perihemorrhagic zone (PHZ) of intracerebral hemorrhage (ICH) are variable. Different mechanisms contribute to secondary neuronal injury after ICH. This multimodal monitoring study investigated early changes in the PHZ of ICH. METHODS: Twenty-four swine were anesthetized, ventilated, and underwent monitoring of vital parameters. Next to an intracranial pressure-probe (ICP), microdialysis (MD), thermodiffusion cerebral blood flow (td-CBF), and oxygen probes (PbrO2) were placed into the gray white matter junction for 12 h of monitoring. ICH was induced using the autologous blood injection model. Pre-defined volumes were 0 ml (sham), 1.5 ml ipsilateral (1.5 ml), 3.0 ml ipsilateral (3.0 ml), and 3.0 ml contralateral (3.0 ml contra). RESULTS: ICP equally increased in all groups after ICH. In the 3.0 ml group tissue oxygenation decreased to ischemic values of 9 ± 7 mmHg early after 6 h of monitoring. This decrease was associated with a significant perfusion reduction from 36 ± 8 ml/100 g/min to 20 ± 10 ml/100 g/min. MD correlated with a threefold lactate/pyruvate ratio increase. Measurements in all other groups were unchanged. CONCLUSION: Multimodal monitoring demonstrates volume-dependent changes of tissue oxygenation, blood flow, and ischemic MD markers in the PHZ independent of increased ICP suggesting early moderate ischemia. No evidence was found for the existence of a perihemorrhagic ischemia in the small hematoma groups.

Minimally invasive endoscopic surgery for treatment of spontaneous intracerebral hematomas: a single-center analysis.

BACKGROUND: Endoscopic minimally invasive surgery to evacuate ICH has been reported to be more effective than conservative treatment or standard surgical craniotomy. However, most of these reports are based on Asian populations, while European reports do not exist. Here, we, therefore, report our experience from a European neurosurgical stroke center. METHODS: The variables assessed were patient characteristics, technical aspects of surgery, surgical complications, the outcomes grade of hematoma evacuation, 30-day mortality, and functional outcome (defined by modified Rankin Scale, mRS). The mRS was dichotomized into favorable (0-3) and unfavorable outcome (4-6). Mortality was compared to external evidence on conservatively and surgically treated patients by Poisson regression analysis with adjustment for ICH score. RESULTS: Thirty-four patients with ICH were analyzed. The mean age was 62 (standard deviation [SD] 12) years, mean hematoma volume (SD) was 84 (35) ml, and mean time from onset to surgery (SD) was 17 (10) h. Operative times did not exceed 1.5 h. A significant mean hematoma reduction (SD) from 84 (35) ml to 21 (30) ml (p < 0.0001) could be achieved, resulting in a median evacuation rate of 87 %. Early complications related to surgery did not occur. A favorable outcome was observed in 44 % of the patients. Overall, 30-day mortality was 18 %. The relative risk of mortality compared to conventional treatment from other studies was 32 % (95 % confidence interval 23-43 %, p = 0.02). CONCLUSIONS: This European surgical stroke center series of an endoscopic operative technique demonstrates safety and efficacy with regard to reduction of hematoma size in patients with large and space-occupying spontaneous ICH. The study suggests that low mortality and acceptable outcomes may be achievable by minimally invasive hematoma surgery. Whether this technique reduces long-term morbidity compared to standard treatment needs to be further investigated in larger prospective randomized controlled trials.

The effect of ketamine on optical and electrical characteristics of spreading depolarizations in gyrencephalic swine cortex.

Spreading depolarization (SD) is a wave of mass neuronal and glial depolarization that propagates across the cerebral cortex and has been implicated in the pathophysiology of brain injury states and migraine with aura. Analgesics and sedatives seem to have a significant effect on SD modulation. Studies have shown that ketamine, an NMDA receptor blocker, has the capacity to influence SD occurrence. The aim of this study was to analyze the dose-dependent effect of ketamine on SD susceptibility through electrocorticography (ECoG) and intrinsic optical signal (IOS) imaging in a gyrencephalic brain. Ketamine in a low-dose infusion (2 mg/kg/h) decreases SD spread and had an effect on the amplitude of SD deflections, as well as on duration, and speed. Moreover, during ketamine infusion at this dose, there was a sustained decrease in the hyperemic response following SD. However, a high-dose infusion (4 mg/kg/h) of ketamine inhibited SD induction and expansion. Furthermore, a high-dose bolus (4 mg/kg), 1 min after stimulation, blocked SD propagation abruptly within 1-2 min, and hindered SD induction and expansion for the following 15-30 min. The results suggest that ketamine may be therapeutically beneficial in preventing SDs. Nonetheless, an adequate dosage and way of administration should be considered and established for human use.

Decompressive craniectomy in patients with aneurysmal subarachnoid hemorrhage: a single-center matched-pair analysis.

BACKGROUND: The role of decompressive craniectomy (DC) in aneurysmal subarachnoid hemorrhage (aSAH) patients is still controversial. In this study we evaluated the effect of DC for aSAH patients. METHODS: A matched-pair analysis was performed to compare the outcomes of patients with DC to those of patients without DC. Among 295 consecutive aSAH patients, 56 required DC. Of the remaining group, 56 matched controls were found. The match was conducted on the basis of epidemiological and potential prognostic factors, such as age, gender, World Federation of Neurosurgical Societies (WFNS) grade, Fisher group and occurrence of vasospasm. RESULTS: Fifty-four of 56 (96.4%) patients with DC were dependent or dead at 1 month, compared with 49 of 56 (87.5%) without DC. There was no significant difference between the groups (p = 0.16). One-year outcomes were available for 108 patients (96.4%). Thirty-nine of 54 (72.2%) patients treated with DC were dependent or dead at 1 year, compared with 30 of 54 (55.6%) patients in the control group. There was no significant difference between the groups (p = 0.11). This result was unaffected by age, sex and WFNS grade. Subgroup analyses whether DC was performed primarily or delayed, and whether DC was performed due to spasm, hematoma or vessel occlusion failed to detect any significant difference. CONCLUSION: There was no significant advantage for patients treated with DC, but more than 25% achieved a good long-term outcome. While the value of DC is deemed uncertain, it may be effective for a very specific subset of aSAH patients. Further comparative studies are needed to resolve this matter.

Delayed anticoagulation-related intracranial haemorrhage after minor head injury.

Treatment with anticoagulants and antiplatelet agents are well-known risk factors for an unfavourable outcome after traumatic brain injury (TBI). Guidelines for decision making in patients who sustained mild head injury do not apply to anticoagulated patients and therefore, in these cases diagnostic and therapeutic procedures have to be tailored patient-specific. A 69-year-old patient was referred to our hospital after sustaining mild head injury. Due to anticoagulation therapy, a cranial computed tomography was carried out and was without pathologic findings. After negative workup for TBI, the patient was admitted to the ward solely because of intermittent cardiac arrhythmia. The next day, the patient developed a hemiparesis and repeated brain imaging showed a large posttraumatic intracranial haematoma which had to be evacuated surgically. In the further clinical course, the patient recovered completely and a cardiac pacemaker was implanted. Emergency physicians have to be highly alert with anticoagulated patients after head injury, even if the trauma was mild and initial diagnostic procedures demonstrate no acute pathology. Delayed traumatic intracranial haemorrhage may have fatal consequences for patients and while the threshold for admission to a hospital ward should be low, adequate observation at home has to be ensured if patients are discharged.

Cortical spreading depression dynamics can be studied using intrinsic optical signal imaging in gyrencephalic animal cortex.

OBJECTIVE: The aim of this study was to co-record electrical changes using electrocorticography (ECoG) and blood volume changes using intrinsic optical signal (IOS) imaging during the induction, propagation, and termination of cortical spreading depolarizations (CSDs). METHODS: Anesthetized male swine were craniotomized and monitored over 16-20 h. A ten-contact electrode strip was placed on the cortex of one hemisphere for ECoG. An optical imaging recording was implemented using a camera with an optical bandpass filter (564 nm, FWHM:15 nm) and a full spectrum light source. CSDs were induced by mechanical and KCl stimulation. Co-occurrences of ECoG baseline shifts and blood volume changes around electrodes were identified. RESULTS: A mean of 3 CSDs per hour were induced, in a total of 4 swine during 80 h of recording. The propagation of the CSDs increased progressively over the monitoring time. IOS enabled us to clearly visualize the induction, propagation, and termination of CSDs with a spatial resolution within the sub-millimeter range. Every CSD recorded using ECoG could also be observed in IOS imaging, although some blood volume changes of CSDs were observed that terminated before reaching any of the ECoG electrodes. CONCLUSION: IOS imaging enables an in vivo evaluation of CSD dynamics over a large surface of gyrencephalic brain.

Evaluating the effects of extended cold ischemia on interstitial metabolite in grafts in kidney transplantation using microdialysis.

PURPOSE: During kidney transplantation (KTx), the length of cold ischemia time (CIT) and the subsequent changes in energy metabolism may lead to variations in interstitial metabolites. Using microdialysis (MD), we evaluated the effects of a short and long CIT on changes of these metabolites. METHODS: Sixteen pigs were randomized in two identical groups, one with a short CIT and the other one with a long CIT. Using MD in the transplanted grafts, we evaluated the parenchyma concentrations of glucose, lactate, pyruvate, glutamate and glycerol in different stages. RESULTS: We noted that during the warm ischemia time (WIT) and in the early post-reperfusion phase glucose levels increased more significantly in the long CIT group and remained high until the end of monitoring. At the end of CIT and during WIT, the long CIT group had a significantly higher glycerol level, but the level dropped gradually in the late post-reperfusion phase and reached a steady state in both groups. CONCLUSIONS: The extended CIT clearly results in considerably impaired graft metabolism. The high interstitial glucose levels within hours after KTx could be considered as a marker of primary delayed function of the graft. Furthermore, the glycerol value could reflect the extent of graft injury during the ischemia time or in case of acute impairment of graft perfusion.

Ectopic recurrent craniopharyngioma of the frontal bone.

Ectopic recurrence of craniopharyngioma is a rare phenomenon after transcranial resection of the primary tumor. The authors present a case of ectopic recurrent adamantinomatous craniopharyngioma of the frontal bone resected 16 years after initial transcranial resection of the primary tumor. The lesion was first radiographically described 12 years after surgery and was adjacent to the osteosynthesis plate that had been implanted at the craniotomy site. The recurrent craniopharyngioma was totally resected via a lateral eyebrow approach. No infiltration of the meninges or the brain was detected. Only 50 cases of ectopic recurrent craniopharyngioma have been described to date, with the present case being the first one with recurrence located at the skull bone. So far 2 mechanisms have been described: contamination with tumor cells alongside the surgical tract and spreading via CSF and the subarachnoid space. The authors reviewed the literature, provided the largest collection of cases so far, and performed basic statistical analysis regarding ectopic recurrence. Pediatric and adult patients as well as male and female ones are affected equally by this phenomenon. The mean time of ectopic recurrence after initial surgery was 7.1 years. Ectopic recurrence, although rare, should always be considered in a patient with a newly diagnosed intracranial lesion who has undergone transcranial craniopharyngioma resection before.