Thomas Reithmeier

Spreading depolarizations occur in human ischemic stroke with high incidence

Cortical spreading depression (CSD) and periinfarct depolarization (PID) have been shown in various experimental models of stroke to cause secondary neuronal damage and infarct expansion. For decades it has been questioned whether CSD or PID occur in human ischemic stroke. Here, we describe CSD and PID in patients with malignant middle cerebral artery infarction detected by subdural electrocorticography (ECoG).

Recurrent Spreading Depolarizations after Subarachnoid Hemorrhage Decreases Oxygen Availability in Human Cerebral Cortex

Delayed ischemic neurological deficit (DIND) contributes to poor outcome in subarachnoid hemorrhage (SAH) patients. Because there is continuing uncertainty as to whether proximal cerebral artery vasospasm is the only cause of DIND, other processes should be considered. A potential candidate is cortical spreading depolarization (CSD)‐induced hypoxia. We hypothesized that recurrent CSDs influence cortical oxygen availability.

Identification and Clinical Impact of Impaired Cerebrovascular Autoregulation in Patients With Malignant Middle Cerebral Artery Infarction

Background and Purpose— To study cerebrovascular autoregulation and its impact on clinical course in patients with impending malignant middle cerebral artery infarction, we used invasive multimodal neuromonitoring, including measurement of cerebral perfusion pressure, tissue oxygen pressure, and microdialysis. Methods— Fifteen patients with a stroke that involved >50% of the middle cerebral artery territory were included. Probes were placed into the ipsilateral frontal lobe. Autoregulation was assessed by calculation of the cerebral perfusion pressure–oxygen reactivity index (COR) and the correlation coefficient (R) of cerebral perfusion pressure and tissue oxygen pressure at 24 and 72 hours after stroke. Results— COR and R at 24 hours after stroke were higher in the 8 patients with a malignant course (ie, massive edema formation) compared with the 7 patients with a benign course (COR, 1.99±1.46 versus 0.68±0.29; R, 0.49±0.28 versus 0.06±0.31; P<0.05), indicating impaired autoregulation in the malignant course group. At 72 hours, further increases in COR and R were observed in the malignant course group in contrast to the benign course group with stable values over time (COR, 3.31±2.38 versus 0.75±0.31; R, 0.75±011 versus 0.36±0.27; P<0.05). With a COR of 0.99, a cutoff value for prediction of a malignant course was found. The lactate-pyruvate ratio was higher in patients with a malignant compared with a benign course at both time points. COR, R, and the lactate-pyruvate ratio showed significant correlations with outcome parameters as a midline shift on cranial computed tomography and score on the modified Rankin scale after 3 months. Conclusions— We found early impairment of cerebrovascular autoregulation in peri-infarct tissue of patients who developed malignant brain edema, whereas autoregulation was preserved in patients with a benign course. Impaired cerebral autoregulation seems to play a key role for development of a malignant course and might serve as a predictive marker. Impaired cerebral autoregulation also accentuates the need for consequent adjustment of cerebral perfusion pressure in patients with impaired autoregulation.

Relevance of ICP and ptiO2 for indication and timing of decompressive craniectomy in patients with malignant brain edema

SummaryBackground. The exact effects of decompressive craniectomy on intracranial pressure (ICP) and cerebral tissue oxygenation (ptiO2) are still unclear. Therefore, we have monitored ICP and ptiO2 intra-operatively and correlated these values to different operative steps during craniectomy.Methods. ICP and ptiO2 values have been monitored both, simultaneously and continuously, in 15 patients with cerebral edema due to posttraumatic or postischemic brain swelling. Indications for craniectomy were an increase in ICP above 25 mmHg or a decrease in ptiO2 below 10 mmHg resistant to conservative treatment (e.g. mannitol, hyperventilation, adequate arterial blood oxygenation, etc.). In all cases, we performed a fronto-temporo-parietal craniectomy (15×12 cm) and dura enlargement with galea-periosteum. During craniectomy, monitoring of ICP and ptiO2 in the affected hemisphere was continued. Values were recorded and correlated with the different operative steps.Findings. We performed craniectomy according to our treatment protocol in 5 patients. Prior to surgery, mean ICP values were 25.6 mmHg (range: 23–29 mmHg), mean ptiO2 values were 5.9 mmHg (range: 2.4–9.5 mmHg), and mean CPP values were 66 mmHg (range: 60–70 mmHg). After removing the bone flap, ICP values dropped to physiological values (mean: 7.4 mmHg), whereas ptiO2 values increased only slightly (mean: 11 mmHg). Opening of the dura resulted in a further decrease of ICP (mean 4.8 mmHg) and an increase of ptiO2 to normal limits (mean: 18.8 mmHg). After skin closure, mean ICP was 6.8 mmHg and mean ptiO2 was 21.7 mmHg, respectively. We found a significant decrease of ICP after craniectomy (p<0.042) and after dura enlargement (p<0.039) as well as a statistically significant increase in ptiO2 after craniectomy (p<0.043) and after dura enlargement (p<0.041).Conclusion. As a large bone flap in decompressive craniectomy is essential for adequate ICP reduction, the results of the presented cases suggest that dura enlargement is the crucial step to restore adequate brain tissue oxygenation and that ptiO2 monitoring could be an important tool for timing craniectomy in the future.

Spinal epidural abscess: prognostic factors and comparison of different surgical treatment strategies.

SummaryBackground. Spinal epidural abscess (SEA) is a rare but potentially devastating disease requiring immediate surgical intervention and appropriate antibiotic treatment. The standard approach to decompress SEA is laminectomy. No report covers comprehensively the indications for the less invasive interlaminar approach, the usefulness of intra-operative ultrasonography and the suspected benefit of inserting a suction-irrigation drainage.Method. A retrospective evaluation of the medical and radiological data was undertaken in 27 consecutive patients with SEA operated on during a period of 10 years by a dorsal approach. Factors influencing outcome were evaluated with special regard to different surgical strategies concerning the invasiveness of the operative approach, the use of intra-operative ultrasound and the use of different drainage systems.Findings. Outcome was mainly determined by the pre-operative neurological condition and the localization of the abscess. Recurrence rate was dependent on the longitudinal extent of the mass and the intra-operative finding of granulation tissue, but not on the administration of a postoperative suction-irrigation drainage. An interlaminar approach was equally matched to a decompression by laminectomy in lumbar SEA concerning the incidence of residual/recurrent abscess formation. In concomitant spondylodiscitis, laminectomy bore the risk of the formation of a postoperative kyphotic deformity. The use of intra-operative ultrasound allowed the visualization of hidden inflammatory masses and, thus, reduced the rate of residual abscess formation.Conclusion. An interlaminar approach should be considered instead of laminectomy in lumbar SEA and in impending anterior column instability due to spondylitis. Intra-operative ultrasound is a beneficial aid for the determination of the extent of decompression during surgery and is practicable even through a narrow interlaminar bony window. The insertion of postoperative suction-irrigation drainage had no beneficial effect on outcome but bore the risk of epidural fluid congestion.

Delayed bilateral craniectomy for treatment of traumatic brain swelling in children: case report and review of the literature.

IntroductionHead injury is the leading cause of accidental death in children. Recent reports have shown the benefit of decompressive craniectomy in children and the role of early timing has been emphasized. However, there is still a lack of data to determine the optimal time for performing craniectomy.Case report In contrast to most reports in the literature, this case report demonstrates successful bilateral decompressive craniectomy in a 10-year-old girl with multiple posttraumatic intracranial lesions and massive traumatic brain swelling on the 8th posttraumatic day.Conclusions Various pathophysiological mechanisms in the genesis of posttraumatic brain swelling make different treatment strategies necessary. Continuous monitoring of intracranial pressure (ICP), as well as serial cranial computed tomography (CCT), can help to differentiate between these mechanisms. Furthermore, repeated clinical and neurophysiological investigations are important for the timing of craniectomy.

Treatment strategies of space-occupying intradural metastases of the cauda equina of nonneurogenic origin

BackgroundCompressive intradural metastases of the cauda equina are a rare site of metastatic spread in systemic cancer. So far, only few reports have been published with conflicting statements concerning a surgical versus nonsurgical approach.MethodFive patients with symptomatic space-occupying intradural metastases of the cauda equina were analyzed retrospectively, focusing on the influence of surgical intervention on pain relief, neurological outcome and thus the patients’ quality of life.FindingsAt the time of diagnosis, all patients were in an advanced metastatic state. Surgical resection was the primary treatment in four patients and radiotherapy in one. Despite infiltration of the cauda rootlets, gross total tumour resection could be achieved in two of the four patients treated surgically. Functional outcome was beneficial in these patients with marked and immediate relief of pain and improvement of motor function even following incomplete tumour resection.ConclusionsSurgical treatment of compressive intradural metastases of the cauda equina seems to be feasible with low operative risk and with the potential benefit of an immediate relief of pain and improvement in motor function and thus an increase in quality of life.