Lumbar spinal epidural arteriovenous fistula with perimedullary venous drainage after endoscopic lumbar surgery

Spinal epidural arteriovenous fistulas (AVFs) with perimedullary venous drainage are rare. This report describes a case of lumbar epidural AVF in a patient with a history of endoscopic lumbar discectomy at the same level 8 years prior to presenting with progressive myelopathy secondary to retrograde venous reflux into the perimedullary vein. A 69-year-old man presented with progressive lower extremity weakness and sensory disturbance and loss of sphincter control 8 years after endoscopic lumbar discectomy for a disc herniation at L4–5 level. Magnetic resonance imaging showed spinal cord edema and dilated intradural perimedullary vessels. Spinal angiography revealed an epidural AVF at the site of the previous endoscopic lumbar surgery with intradural perimedullary venous drainage. The fistula was successfully occluded via endovascular transarterial embolization, and the patient had stabilization of his neurological deficits. Lumbar spinal epidural AVFs, especially those associated with iatrogenic trauma, are rare. Endoscopic surgical procedure can occlude the epidural venous plexus and disturb venous drainage, thereby inducing local venous hypertension and leading to epidural AVF with perimedullary venous drainage. This type of pathology should be considered within the differential diagnosis of delayed neurological deterioration after spinal surgery.     

Stromal Cell‐Derived Factor 1α Induces Accumulation of Intraveneously Administered Marrow‐Derived Stromal Cells in the Partially Obstructed Rat Bladder

Objectives: We investigated the time course of the stromal cell‐derived factor 1α (SDF1α) expression and behavior of intravenously administered bone marrow‐derived stromal (BMS) cells in the urinary bladder of partial bladder outlet obstruction (PBOO) rats. Methods: Study 1: Recombinant SDF1α or saline was directly injected into the bladder wall of female rats followed by intravenous administration of BMS cells isolated from green fluorescent protein (GFP) transgenic rats. The bladder was examined with immunohistochemistry to determine whether SDF1α would enhance migration of BMS cells to the bladder. Study 2: Following surgery of PBOO or sham in female rats, bladders were removed on days 1–14, and expression of hypoxia inducible factor 1α (HIF1α) and SDF1α were examined with real‐time polymerase chain reaction (PCR) to determine if PBOO preferentially increased their expression. Study 3: Female rats underwent PBOO or sham surgery followed by intravenous administration of GFP‐positive BMS cells. Bladders were examined with immunohistochemistry on days 1–14 to determine whether BMS cells preferentially accumulated in the bladder. Results: BMS cells were accumulated in the injection site of SDF1α but not saline in the bladder. SDF1α and HIF1α increased at day 1 after PBOO compared to sham. More BMS cells accumulated in the bladder of PBOO on day 1, and some BMS cells expressed smooth muscle phenotypes by day 14. Conclusion: SDF1α induced with ischemia/hypoxia due to PBOO is implicated in the accumulation of BMS cells in the bladder and regeneration of the bladder for PBOO.     

Fracture and Collapse of Balloon-Expandable Stents in the Bilateral Common Iliac Arteries Due to Shiatsu Massage

We report a case of stent fracture and collapse of balloon-expandable stents caused by shiatsu massage. A 76-year-old man presented with complaints of intermittent claudication of the right lower extremity. Stenoses of the bilateral common iliac arteries (CIAs) were detected. Balloon-expandable stents were deployed in both CIAs, resulting in resolution of symptoms. Five months later, pelvis x-ray showed collapse of both stents. Despite the stent collapse, the patient was asymptomatic, and his ankle brachial index values were within the normal range. Further history showed that the patient underwent daily shiatsu therapy in the umbilical region, which may have triggered collapse of the stent. Physicians should advise patients to avoid compression of the abdominal wall after implantation of a stent in the iliac artery.     

Microwave Ablation Compared with Radiofrequency Ablation for Breast Tissue in an Ex Vivo Bovine Udder Model

Purpose

To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue.

Materials and Methods

MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation.

Results

The mean short-axis diameters of the coagulation zones were 1.34 ± 0.14, 1.45 ± 0.13, and 1.74 ± 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 ± 0.09 and 1.26 ± 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 ± 0.65, 2.85 ± 0.72, and 4.45 ± 0.47 cm³ for MW ablation at outputs of 25W, 35W, and 45W and 1.18 ± 0.30 and 2.29 ± 0.55 cm³ got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations.

Conclusion

MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.     

Deteriorating consumptive coagulopathy with type III endoleak following endovascular repair for abdominal aortic aneurysm associated with liver cirrhosis.

PURPOSE: To report a case of deteriorating consumptive coagulopathy with type III endoleak following endovascular aneurysm repair (EVAR) of the abdominal aorta associated with liver cirrhosis. CASE REPORT: A 72-year-old man with liver cirrhosis developed type III endoleak following EVAR. Spontaneous intramuscular hematoma developed due to deteriorating consumptive coagulopathy induced by type III endoleak and liver dysfunction. Although additional EVAR was performed at 52 months after primary EVAR, the patient died due to multiorgan failure and multifocal hematoma of the muscles and subserosa. CONCLUSION: EVAR for patients with liver dysfunction and coagulopathy should be considered with great caution. We suggest that prompt and adequate treatment using an endovascular technique or surgical repair should be performed for patients with liver dysfunction, coagulopathy, and turbulent endoleak, even if the coagulopathies are worse compared to before EVAR.     

A case of pulmonary arteriovenous malformation treated by transcatheter embolization using coils]

The patient was a 21-year-old woman who, at 16 years old, had had no subjective symptoms. She was referred to our hospital because of abnormal shadows in the middle of the left lung that were seen on a chest radiograph during a school medical screening. In her first examination at our hospital, CT revealed tumor-like shadows with diameters of 2.0 cm in Lt-S6 and 0.5 cm in Rt-S5, together with arteries and veins. Lung ventilation and blood flow scintigraphy was used to obtain images of both kidneys and the head, and as a result, a pulmonary arteriovenous malformation (PAVM) was diagnosed. Because of a low shunt fraction of 10.8%, the patient was only kept under observation. However, at 21 years of age, she complained of dyspnea with exercise and was admitted to the hospital for further examination. Chest CT showed an increase in the diameter of the arteriovenous malformation (AVM) to 2.7 cm, and 3-D image reconstruction clearly revealed the position of the tumor in relation to the pulmonary artery and vein. The shunt fraction had increased to 18.3%. Coil embolization was therefore performed to A6b, the artery feeding the AVM (using interlocking detachable coils of 6 mm-10 cm and 8 mm-20 cm, and Trufill coils of two 7 mm-6 cm and 5 mm-4 cm). The patient had no serious postoperative complications. A decreased AVM diameter of 1.7 cm and an improved shunt fraction of 11% were observed, and she was discharged from the hospital. Since then, she has been well, without dyspnea, and her chest films show only coils and no aggravation of other AVMs. AVMs generally have no symptoms, but they can cause severe complications such as hypoxia from a right-to-left shunt, hemoptysis, hemothorax, and brain abscesses. Coil embolization should be considered more often for the treatment of AVM because it is safer, more effective and less invasive than traditional operations.     

Oxido-reductive regulation of vascular remodeling by receptor tyrosine kinase ROS1

Angioplasty and stenting is the primary treatment for flow-limiting atherosclerosis; however, this strategy is limited by pathological vascular remodeling. Using a systems approach, we identified a role for the network hub gene glutathione peroxidase-1 (GPX1) in pathological remodeling following human blood vessel stenting. Constitutive deletion of Gpx1 in atherosclerotic mice recapitulated this phenotype of increased vascular smooth muscle cell (VSMC) proliferation and plaque formation. In an independent patient cohort, gene variant pair analysis identified an interaction of GPX1 with the orphan protooncogene receptor tyrosine kinase ROS1. A meta-analysis of the only genome-wide association studies of human neointima-induced in-stent stenosis confirmed the association of the ROS1 variant with pathological remodeling. Decreased GPX1 expression in atherosclerotic mice led to reductive stress via a time-dependent increase in glutathione, corresponding to phosphorylation of the ROS1 kinase activation site Y2274. Loss of GPX1 function was associated with both oxidative and reductive stress, the latter driving ROS1 activity via s-glutathiolation of critical residues of the ROS1 tyrosine phosphatase SHP-2. ROS1 inhibition with crizotinib and deglutathiolation of SHP-2 abolished GPX1-mediated increases in VSMC proliferation while leaving endothelialization intact. Our results indicate that GPX1-dependent alterations in oxido-reductive stress promote ROS1 activation and mediate vascular remodeling.     

Evaluation of cellular adhesions on silicone and poly(methyl methacrylate) intraocular lenses in monkey eyes: An electron microscopic study

PURPOSE: To assess the biocompatibility of intraocular lens (IOL) material by studying the number of cells adhering to IOLs in monkey eyes. SETTING: Department of Ophthalmology, Kyushu University, Fukuoka, Japan. METHODS: Silicone or poly(methyl methacrylate) (PMMA) IOL implantation was performed in 21 monkeys. One eye of each animal had surgery. The IOL-implanted eyes were enucleated 1, 2, 3, 5, and 7 days and 1, 3, 4, 5, and 9 months after the procedure. One eye was studied at each time. Cells on the anterior IOL surface were photographed using a scanning electron microscope, counted and assessed with NEC, Graphtec, and Nikon equipment, and then observed using a transmission electron microscope. RESULTS: Leukocytes, macrophages, and giant cells were found on the anterior IOL surface. Numerous cells were observed on the PMMA IOLs in the early postoperative period; they gradually decreased. Few cells were seen on the silicone IOLs during the course of the study. The giant cells became larger during the postoperative period. CONCLUSION: The foreign-body reaction to silicone IOLs in monkey eyes was less than that to PMMA IOLs.