Influence of sex and hormonal status on initial impact and neurocognitive outcome after subarachnoid haemorrhage in rats.

The aim of this study was to detect differences in functional outcome after experimental subarachnoid haemorrhage (SAH) in rodents with different hormonal status. For this purpose, the endovascular perforation model was applied to four groups of Sprague-Dawley-Rats: male intact, male neutered, female intact and female neutered animals. Initial impact was measured by ICP, CPP and cerebral blood flow in the first hour after SAH. From day 4-14, the modified hole board test was applied to assess functional and neuro-cognitive outcome. Histological outcome was examined in the motor cortex and hippocampus of each hemisphere. Mortality was highest in the female intact group albeit not statistically significant. Physiologic parameters did not differ significantly between groups either. In the modified hole board test, male intact animals showed a greater impairment of declarative memory than the female intact and neutered groups. However, male intact animals showed greater avoidance behaviour and male animals revealed higher anxiety levels independent of hormonal status. No differences in histological damage of hippocampus and motor cortex between groups could be shown. We therefore speculate that the marginal deficits in cognitive performance that are shown by the male intact group in the modified hole board test are mostly caused by higher anxiety levels and cannot be interpreted as pure cognitive impairment.

Ankylosing Spinal Disease-Diagnosis and Treatment of Spine Fractures.

BACKGROUND: In patients with ankylosing spinal disease, including ankylosing spondylitis and diffuse idiopathic skeletal hyperostosis, even low-impact trauma can lead to complex injuries. The injuries seem to be highly unstable and associated with greater mortality rates compared with the general spine trauma population. METHODS: We reviewed the medical records of a consecutive series of 41 patients (34 men, 7 women) with ankylosing spinal disease and unstable traumatic spine injuries who were admitted to our department from 2007 to 2016. RESULTS: The mean patient age was 73.4 ± 12.7 years. Of the 41 patients, 24 (58.5%) had ankylosing spondylitis and 17 (41.5%) had diffuse idiopathic skeletal hyperostosis. Low-velocity accidents were documented in 38 patients (92.7%). The most frequent injuries were type B spine fractures (61.0%). Accompanying spinal epidural hematoma was detected using magnetic resonance imaging in 12 patients (29.3%) but was not found by radiography or computed tomography. Of the 41 patients, 24 (58.5%) presented with American Spinal Injury Association impairment scale (AIS) grade E, 6 (14.6%) with grade D, and 8 (19.6%) with grade C or worse. All the patients had undergone internal fixation. All but 1 (97.6%) had received posterior fixation. In 25 (61%), a combined approach was performed. Five patients died of early complications. Of the 36 discharged patients, 11 died during the follow-up period and 1 was lost to follow-up. The surviving 24 patients had a median follow-up of 733 ± 576 days; 21 had AIS grade E, 2 had AIS grade D, and 1 had AIS grade C. CONCLUSIONS: A thorough diagnostic evaluation with multislice computed tomography and magnetic resonance imaging can reveal injuries that would remain undetected on conventional radiographs. A combined approach or posterior-only fixation seems safe.

Early Morbidity and Mortality in 50 Very Elderly Patients After Posterior Atlantoaxial Fusion for Traumatic Odontoid Fractures.

BACKGROUND: Traumatic odontoid fractures (tOFs) in the very elderly are associated with high morbidity and mortality. The best treatment strategy (conservative vs. surgery) is still unclear. METHODS: Between April 2008 and April 2014, fifty (17 male, 33 female) patients (mean age 87.2 ± 4.4 years; range: 80-99) were included in this retrospective cohort study. All patients underwent posterior fusion surgery for tOF. Early outcome, morbidity and mortality, length of hospital and intensive care unit (ICU) stay, comorbidities, and perioperative complications were assessed. RESULTS: The mean age-adjusted Charlson Comorbidity Index (CCI) was 5.8 ± 3.9 (range: 0-13), and the mean American Society of Anesthesiologists score was 3 ± 0.5 (range: 2-4). Surgery was delayed in 48% of patients. Thirty percent of patients had preoperative complications (72.4% severe), of which a leading cause was dysphagia with subsequent pneumonia, and 18% required preoperative assessment or improvement of health status. Surgery-related complications were experienced in 14% with no neurovascular lesion. Postoperative medical complications occurred in 52% of patients (67.3% severe). Major complications were mostly respiratory/pulmonary (66.7%), of which postoperative pneumonia (36.4%) was leading. Twenty-four percent of patients were ICU monitored. Mean length of ICU stay was 9 ± 6.6 days (1-20). Mean length of hospital stay was 15 ± 8.6 days (4-56). There was no in-hospital mortality, and 30-day mortality was 6%. CONCLUSIONS: Posterior fusion for tOF in patients 80 years or older seems to be a feasible treatment option in these high-risk patients. Despite a high incidence of severe comorbidities and perioperative complications, outcome was satisfactory. LEVEL OF EVIDENCE: Our research was a retrospective cohort study, Level III.

The far-lateral approach: destruction of the condyle does not necessarily result in clinically evident craniovertebral junction instability.

OBJECT Far-lateral or extreme-lateral approaches to the skull base allow access to the lateral and anterior portion of the lower posterior fossa and foramen magnum. These approaches include a certain extent of resection of the condyle, which potentially results in craniocervical junction instability. However, it is debated what extent of condyle resection is safe and at what extent of condyle resection an occipitocervical fusion should be recommended. The authors reviewed cases of condyle resection/destruction with regard to necessity of occipitocervical fusion. METHODS The authors conducted a retrospective analysis of all patients in whom a far- or extreme-lateral approach including condyle resection of various extents was performed between January 2007 and December 2014. RESULTS Twenty-one consecutive patients who had undergone a unilateral far- or extreme-lateral approach including condyle resection were identified. There were 10 male and 11 female patients with a median age of 61 years (range 22-83 years). The extent of condyle resection was 25% or less in 15 cases, 50% in 1 case, and greater than 75% in 5 cases. None of the patients who underwent condyle resection of 50% or less was placed in a collar postoperatively or developed neck pain. Two of the patients with condyle resection of greater than 75% were placed in a semirigid collar for a period of 3 months postoperatively and remained free of pain after this period. At last follow-up none of the cases showed any clear sign of radiological or clinical instability. CONCLUSIONS The unilateral resection or destruction of the condyle does not necessarily result in craniocervical instability. No evident instability was encountered even in the 5 patients who underwent removal of more than 75% of the condyle. The far- or extreme-lateral approach may be safer than generally accepted with regard to craniocervical instability as generally considered and may not compel fusion in all cases with condylar resection of more than 75%.

Impact of anesthesia on pathophysiology and mortality following subarachnoid hemorrhage in rats.

BACKGROUND: Anesthesia is indispensable for in vivo research but has the intrinsic potential to alter study results. The aim of the current study was to investigate the impact of three common anesthesia protocols on physiological parameters and outcome following the most common experimental model for subarachnoid hemorrhage (SAH), endovascular perforation. METHODS: Sprague-Dawley rats (n = 38) were randomly assigned to (1) chloral hydrate, (2) isoflurane or (3) midazolam/medetomidine/fentanyl (MMF) anesthesia. Arterial blood gases, intracranial pressure (ICP), mean arterial blood pressure (MAP), cerebral perfusion pressure (CPP), and regional cerebral blood flow (rCBF) were monitored before and for 3 hours after SAH. Brain water content, mortality and rate of secondary bleeding were also evaluated. RESULTS: Under baseline conditions isoflurane anesthesia resulted in deterioration of respiratory parameters (arterial pCO2 and pO2) and increased brain water content. After SAH, isoflurane and chloral hydrate were associated with reduced MAP, incomplete recovery of post-hemorrhagic rCBF (23 ± 13% and 87 ± 18% of baseline, respectively) and a high anesthesia-related mortality (17 and 50%, respectively). Anesthesia with MMF provided stable hemodynamics (MAP between 100-110 mmHg), high post-hemorrhagic rCBF values, and a high rate of re-bleedings (> 50%), a phenomenon often observed after SAH in humans. CONCLUSION: Based on these findings we recommend anesthesia with MMF for the endovascular perforation model of SAH.

Safety and efficacy of a new percutaneously implantable interspinous process device.

BACKGROUND: Lumbar spinal stenosis is a degenerative disease of the elderly population. Although microsurgical decompression has shown good long-term results, percutaneous techniques could provide an alternative in the presence of significant comorbidities. METHOD: Eighty-seven interspinous process decompression devices (In-space; Synthes, Umkirch, Germany) were implanted percutaneously in up to three segments of 50 patients. Outcome was assessed directly after surgery, at 6-8 weeks, and at average follow-up of 1 year (11.8 ± 6 months). Assessment included complications, pain and spinal claudication, neurodeficit, time to recurrence of symptoms, and time to second surgery. Subgroups with additional low back pain at presentation and mild spondylolisthesis were analyzed separately. FINDINGS: Intraoperative complications were rare (one misplacement and two cases of failed implantation); average operation time was 16.4 ± 12.2 min per segment. Initial response was very good with 72% good or excellent relief of symptoms. After a 1-year follow-up, 42% reported of lasting relief from spinal claudication. Thirteen percent of these complained about lasting or new-onset low back pain. A second surgery had been performed in 22%. Subgroup analysis was performed for patients presenting with additional low back pain and spondylolisthesis patients. No significant differences could be noted between subgroups. CONCLUSIONS: The In-space is a percutaneous treatment option of claudication in patients with lumbar spinal stenosis. Compared with microsurgical decompression surgery, recurrence rate within 1 year is, however, high and the device seems not suitable for the treatment of low back pain. Therefore, the authors suggest that the device should presently be used primarily in controlled clinical trials in order to get more information concerning the optimal indication.

Mild hypothermia (33 degrees C) reduces intracranial hypertension and improves functional outcome after subarachnoid hemorrhage in rats.

OBJECTIVE: After a subarachnoid hemorrhage (SAH), the primary cause of mortality is secondary brain injury occurring within the first 48 hours after the initial bleeding. Because of the unknown pathophysiology of these early events, therapeutic approaches are scarce. Because mild hypothermia (33 degrees C) is among the strongest neuroprotectants known so far, the aim of this study was to investigate acute and delayed effects of hypothermia if applied after SAH. METHODS: Male Sprague-Dawley rats were subjected to SAH and randomly assigned to the following groups: 1) SAH under normothermia, 2) SAH followed by 2 hours of hypothermia starting 1 hour after the bleeding, and 3) SAH followed by 2 hours of hypothermia starting 3 hours after the bleeding. Cerebral blood flow and intracranial pressure were continuously measured up to 6 hours after SAH. Mortality, neurological deficits, and body weight were assessed from postoperative day 1 to day 7. Brain water content and morphological brain damage were quantified 24 hours and 7 days after SAH, respectively. RESULTS: Mild hypothermia reduced intracranial pressure (P < 0.001) and posthemorrhagic neurological deficits (P < 0.05) and improved postoperative weight gain significantly (P < 0.05). Mortality, cerebral blood flow, and the formation of cerebral edema were not significantly influenced by mild hypothermia. CONCLUSION: The current results show that mild hypothermia (33 degrees C) exhibits sustained neuroprotection if applied up to 3 hours after SAH. Overall, mild hypothermia seems to be an effective neuroprotective strategy after SAH and should therefore be evaluated as a treatment option for SAH in patients.