Do optic nerve head and visual field parameters in patients with obstructive sleep apnea syndrome differ from those in control individuals?

BACKGROUND It has been suggested that sleep apnea syndrome may play a role in normal-tension glaucoma contributing to optic nerve damage. The purpose of this study was to evaluate if optic nerve and visual field parameters in individuals with sleep apnea syndrome differ from those in controls. PATIENTS AND METHODS From the records of the sleep laboratory at the University Hospital in Bern, Switzerland, we recruited consecutive patients with severe sleep apnea syndrome proven by polysomnography, apnea-hypopnea index >20, as well as no sleep apnea controls with apnea-hypopnea index <10. Participants had to be unknown to the ophtalmology department and had to have no recent eye examination in the medical history. All participants underwent a comprehensive eye examination, scanning laser polarimetry (GDx VCC, Carl Zeiss Meditec, Dublin, California), scanning laser ophthalmoscopy (Heidelberg Retina Tomograph II, HRT II), and automated perimetry (Octopus 101 Programm G2, Haag-Streit Diagnostics, Koeniz, Switzerland). Mean values of the parameters of the two groups were compared by t-test. RESULTS The sleep apnea group consisted of 69 eyes of 35 patients; age 52.7 ± 9.7 years, apnea-hypopnea index 46.1 ± 24.8. As controls served 38 eyes of 19 patients; age 45.8 ± 11.2 years, apnea-hypopnea index 4.8 ± 1.9. A difference was found in mean intraocular pressure, although in a fully overlapping range, sleep apnea group: 15.2 ± 3.1, range 8-22 mmHg, controls: 13.6 ± 2.3, range 9-18 mmHg; p<0.01. None of the extended visual field, optic nerve head (HRT) and retinal nerve fiber layer (GDx VCC) parameters showed a significant difference between the groups. CONCLUSION Visual field, optic nerve head, and retinal nerve fiber layer parameters in patients with sleep apnea did not differ from those in the control group. Our results do not support a pathogenic relationship between sleep apnea syndrome and glaucoma.

Elevated liver regeneration in response to pharmacological reduction of elevated portal venous pressure by terlipressin after partial hepatectomy.

BACKGROUND Liver regeneration is of crucial importance for patients undergoing living liver transplantations or extended liver resections and can be associated with elevated portal venous pressure, impaired hepatic regeneration, and postoperative morbidity. The aim of this study was to assess whether reduction of portal venous pressure by terlipressin improves postoperative liver regeneration in normal and steatotic livers after partial hepatectomy in a rodent model. METHODS Portal venous pressure was assessed after minor (30%), standard (60%), or extended (80%) partial hepatectomy (PH) in mice with and without liver steatosis. Liver regeneration was assessed by BrdU incorporation and Ki-67 immunostaining. RESULTS Portal venous pressure was significantly elevated post-PH in mice with normal and steatotic livers compared to sham-operated mice. Reduction of elevated portal pressure after 80% PH by terlipressin was associated with an increase of hepatocellular proliferation. In steatotic livers, animals treated with terlipressin had an increase in liver regeneration after 30% PH and increased survival after 60% PH. Mechanistically, terlipressin alleviated IL-6 mRNA expression following PH and down-regulated p21 and GADD45 mRNA suggesting a reduction of cell cycle inhibition and cellular stress. CONCLUSIONS Reduction of elevated portal pressure post-PH by the use of terlipressin improves liver regeneration after PH in lean and steatotic mouse livers.

Support of hepatic regeneration by trophic factors from liver-derived mesenchymal stromal/stem cells

Mesenchymal stromal/stem cells (MSCs) have multilineage differentiation potential and as such are known to promote regeneration in response to tissue injury. However, accumulating evidence indicates that the regenerative capacity of MSCs is not via transdifferentiation but mediated by their production of trophic and other factors that promote endogenous regeneration pathways of the tissue cells. In this chapter, we provide a detailed description on how to obtain trophic factors secreted by cultured MSCs and how they can be used in small animal models. More specific, in vivo models to study the paracrine effects of MSCs on regeneration of the liver after surgical resection and/or ischemia and reperfusion injury are described.

Bone marrow-derived mesenchymal stromal cells improve vascular regeneration and reduce leukocyte-endothelium activation in critical ischemic murine skin in a dose-dependent manner

BACKGROUND AIMS Stem cells participate in vascular regeneration following critical ischemia. However, their angiogenic and remodeling properties, as well as their role in ischemia-related endothelial leukocyte activation, need to be further elucidated. Herein, we investigated the effect of bone marrow-derived mesenchymal stromal cells (BM-MSCs) in a critically ischemic murine skin flap model. METHODS Groups received either 1 × 10(5), 5 × 10(5), or 1 × 10(6) BM-MSCs or cell-free conditioned medium (CM). Controls received sodium chloride. Intravital fluorescence microscopy was performed for morphological and quantitative assessment of micro-hemodynamic parameters over 12 days. RESULTS Tortuosity and diameter of conduit-arterioles were pronounced in the MSC groups (P < 0.01), whereas vasodilation was shifted to the end arteriolar level in the CM group (P < 0.01). These effects were accompanied by angiopoietin-2 expression. Functional capillary density and red blood cell velocity were enhanced in all treatment groups (P < 0.01). Although a significant reduction of rolling and sticking leukocytes was observed in the MSC groups with a reduction of diameter in postcapillary venules (P < 0.01), animals receiving CM exhibited a leukocyte-endothelium interaction similar to controls. This correlated with leukocyte common antigen expression in tissue sections (P < 0.01) and p38 mitogen-activated protein kinase expression from tissue samples. Cytokine analysis from BM-MSC culture medium revealed a 50% reduction of pro-inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-12, tumor necrosis factor-α, interferon-γ) and chemokines (keratinocyte chemoattractant, granulocyte colony-stimulating factor) under hypoxic conditions. DISCUSSION We demonstrated positive effects of BM-MSCs on vascular regeneration and modulation of endothelial leukocyte adhesion in critical ischemic skin. The improvements after MSC application were dose-dependent and superior to the use of CM alone.

What is the frequency of nerve injuries associated with acetabular fractures?

BACKGROUND Acetabular fractures and surgical interventions used to treat them can result in nerve injuries. To date, only small case studies have tried to explore the frequency of nerve injuries and their association with patient and treatment characteristics. High-quality data on the risk of traumatic and iatrogenic nerve lesions and their epidemiology in relation to different fracture types and surgical approaches are lacking. QUESTIONS/PURPOSES The purpose of this study was to determine (1) the proportion of patients who develop nerve injuries after acetabular fracture; (2) which fracture type(s) are associated with increased nerve injury risk; and (3) which surgical approach was associated with the highest proportion of patients developing nerve injuries using data from the German Pelvic Trauma Registry. Two secondary aims were (4) to assess hospital volume-nerve-injury relationship; and (5) internal data validity. METHODS Between March 2001 and June 2012, 2236 patients with acetabular fractures were entered into a prospectively maintained registry from 29 hospitals; of those, 2073 (92.7%) had complete records on the endpoints of interest in this retrospective study and were analyzed. The neurological status in these patients was captured at their admission and at the discharge. A total of 1395 of 2073 (67%) patients underwent surgery, and the proportions of intervention-related and other hospital-acquired nerve injuries were obtained. Overall proportions of patients developing nerve injuries, risk based on fracture type, and risk of surgical approach type were analyzed. RESULTS The proportion of patients being diagnosed with nerve injuries at hospital admission was 4% (76 of 2073) and at discharge 7% (134 or 2073). Patients with fractures of the "posterior wall" (relative risk [RR], 2.0; 95% confidence interval [CI], 1.4-2.8; p=0.001), "posterior column and posterior wall" (RR, 2.9; CI, 1.6-5.0; p=0.002), and "transverse+posterior wall" fracture (RR, 2.1; CI, 1.3-3.5; p=0.010) were more likely to have nerve injuries at hospital discharge. The proportion of patients with intervention-related nerve injuries and that of patients with other hospital-acquired nerve injuries was 2% (24 of 1395 and 46 of 2073, respectively). They both were associated with the Kocher-Langenbeck approach (RR, 3.0; CI, 1.4-6.2; p=0.006; and RR, 2.4; CI, 1.4-4.3; p=0.004, respectively). CONCLUSIONS Acetabular fractures with the involvement of posterior wall were most commonly accompanied with nerve injuries. The data suggest also that Kocher-Langenbeck approach to the pelvic ring is associated with a higher risk of perioperative nerve injuries. Trauma surgeons should be aware of common nerve injuries, particularly in posterior wall fractures. The results of the study should help provide patients with more exact information on the risk of perioperative nerve injuries in acetabular fractures. LEVEL OF EVIDENCE Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Clinical validity of the nerve root sedimentation sign in patients with suspected lumbar spinal stenosis

BACKGROUND CONTEXT The nerve root sedimentation sign in transverse magnetic resonance imaging has been shown to discriminate well between selected patients with and without lumbar spinal stenosis (LSS), but the performance of this new test, when used in a broader patient population, is not yet known. PURPOSE To evaluate the clinical performance of the nerve root sedimentation sign in detecting central LSS above L5 and to determine its potential significance for treatment decisions. STUDY DESIGN Retrospective cohort study. PATIENT SAMPLE One hundred eighteen consecutive patients with suspected LSS (52% women, median age 62 years) with a median follow-up of 24 months. OUTCOME MEASURES Oswestry disability index (ODI) and back and leg pain relief. METHODS We performed a clinical test validation study to assess the clinical performance of the sign by measuring its association with health outcomes. Subjects were patients referred to our orthopedic spine unit from 2004 to 2007 before the sign had been described. Based on clinical and radiological diagnostics, patients had been treated with decompression surgery or nonsurgical treatment. Changes in the ODI and pain from baseline to 24-month follow-up were compared between sedimentation sign positives and negatives in both treatment groups. RESULTS Sixty-nine patients underwent surgery. Average baseline ODI in the surgical group was 54.7%, and the sign was positive in 39 patients (mean ODI improvement 29.0 points) and negative in 30 (ODI improvement 28.4), with no statistically significant difference in ODI and pain improvement between groups. In the 49 patients of the nonsurgical group, mean baseline ODI was 42.4%; the sign was positive in 18 (ODI improvement 0.6) and negative in 31 (ODI improvement 17.7). A positive sign was associated with a smaller ODI and back pain improvement than negative signs (both p<.01 on t test). CONCLUSIONS In patients commonly treated with decompression surgery, the sedimentation sign does not appear to predict surgical outcome. In nonsurgically treated patients, a positive sign is associated with more limited improvement. In these cases, surgery might be effective, but this needs investigation in prospective randomized trials (Australian New Zealand Clinical Trial Registry, number ACTRN12610000567022).

MRI-guided and CT-guided cervical nerve root infiltration therapy: a cost comparison

PURPOSE To evaluate and compare the costs of MRI-guided and CT-guided cervical nerve root infiltration for the minimally invasive treatment of radicular neck pain. MATERIALS AND METHODS Between September 2009 and April 2012, 22 patients (9 men, 13 women; mean age: 48.2 years) underwent MRI-guided (1.0 Tesla, Panorama HFO, Philips) single-site periradicular cervical nerve root infiltration with 40 mg triamcinolone acetonide. A further 64 patients (34 men, 30 women; mean age: 50.3 years) were treated under CT fluoroscopic guidance (Somatom Definition 64, Siemens). The mean overall costs were calculated as the sum of the prorated costs of equipment use (purchase, depreciation, maintenance, and energy costs), personnel costs and expenditure for disposables that were identified for MRI- and CT-guided procedures. Additionally, the cost of ultrasound guidance was calculated. RESULTS The mean intervention time was 24.9 min. (range: 12 - 36 min.) for MRI-guided infiltration and 19.7 min. (range: 5 - 54 min.) for CT-guided infiltration. The average total costs per patient were EUR 240 for MRI-guided interventions and EUR 124 for CT-guided interventions. These were (MRI/CT guidance) EUR 150/60 for equipment use, EUR 46/40 for personnel, and EUR 44/25 for disposables. The mean overall cost of ultrasound guidance was EUR 76. CONCLUSION Cervical nerve root infiltration using MRI guidance is still about twice as expensive as infiltration using CT guidance. However, since it does not involve radiation exposure for patients and personnel, MRI-guided nerve root infiltration may become a promising alternative to the CT-guided procedure, especially since a further price decrease is expected for MRI devices and MR-compatible disposables. In contrast, ultrasound remains the less expensive method for nerve root infiltration guidance.