Takanori Tokuda

Cement Leakage in Percutaneous Vertebroplasty for Osteoporotic Compression Fractures With or Without Intravertebral Clefts

OBJECTIVE The purpose of our study was to compare the incidence and location of cement leakage in percutaneous vertebroplasty for osteoporotic compression fractures with and without intravertebral clefts. MATERIALS AND METHODS Percutaneous vertebroplasty was performed in 120 consecutive patients with 300 osteoporotic compression fractures. The cement volume injected was recorded. The cement leakage was evaluated using spinal radiography, MRI, and fluoroscopy during the procedure and CT after the procedure. RESULTS One hundred seven vertebrae contained intervertebral clefts, and 193 vertebrae had no clefts. The cement volume injected (+/- SD) was 4.0 +/- 2.0 and 3.6 +/- 1.6 mL into vertebrae with clefts and without clefts, respectively, with no statistically significant difference (p = 0.14). There was no statistically significant difference in the incidence of cement leakage between vertebrae with clefts (53 of 107) and those without clefts (78 of 193) (p = 0.13). Leakage occurred into the epidural veins (12 of 107), perivertebral soft tissues (7 of 107), disks (41 of 107), intervertebral foramen (1 of 107), and spinal canal (1 of 107) in fractures with clefts and into the epidural veins (47 of 193), perivertebral soft tissues (13 of 193), disks (25 of 193), paravertebral veins (5 of 193), large vein (2 of 193), lung (2 of 193), intervertebral foramen (1 of 193), and spinal canal (1 of 193) in fractures without clefts. Cement leakage into the epidural vein was significantly more frequent in vertebrae without clefts (p < 0.01). Disk leakage was significantly more frequent in vertebrae with clefts compared with those without clefts (p < 0.01). CONCLUSION There was no statistically significant difference in the incidence of cement leakage between vertebrae with clefts and without clefts. However, cement leakage into the epidural vein was significantly more frequent in vertebrae without clefts and disk leakage was significantly more frequent in vertebrae with clefts.

Transcatheter embolization for peripheral pseudoaneurysms with n-butyl cyanoacrylate

The purpose of this study is to evaluate the clinical efficacy of transcatheter embolization for pseudoaneurysms of peripheral arteries with n-butyl cyanoacrylate (NBCA). From November 2000 to February 2008, 17 patients with 18 pseudoaneurysms were treated by transcatheter embolization at our affiliated hospitals. The locations of the pseudoaneurysms were right hepatic artery (n=3), renal artery (n=5), splenic artery (n=2), gastroduodenal artery (n=2), common hepatic artery (n=1), pancreatic arcade (n=1), external iliac artery (n=1), internal iliac artery (n=1), internal thoracic artery (n=1), and left gastric artery (n=1). We assessed technical success rate, embolization methods, and clinical course in this study. The technical success rate was 94.4% (17/18 cases). Embolization methods were isolation (n=17) and packing (n=1). Only NBCA was used in 14 cases, both coils and NBCA were used in four cases. Six patients were in shock prior to the procedure, but all patients recovered immediately after embolization procedure including transfusion. None of the patients died of procedure-related factors or had notable postoperative complications, but three patients died within a week of the procedure because of deterioration of the underlying disease. In conclusion, transcatheter embolization of pseudoaneurysms with NBCA is a safe and effective technique for treatment.

Water-soluble Polyvinyl Alcohol Microspheres for Temporary Embolization: Development and in Vivo Characteristics in a Pig Kidney Model

PURPOSE To preliminarily examine whether solubility of water-soluble polyvinyl alcohol (PVA) microspheres in blood plasma changes in proportion to their degrees of saponification. The study also examined their feasibility as a temporary embolic agents in the pig renal artery. MATERIALS AND METHODS Three types of PVA microspheres with the degrees of saponification of 97 mol% (S97), 98 mol% (S98), and 99 mol% (S99) were prepared. Seven kidneys in seven miniature pigs were embolized and divided into three groups so there would be at least two kidneys for each type of PVA. One animal in each group was euthanized immediately after angiography at 3 hours after embolization and the other one at 7 days after. In addition, one animal embolized with S99 microspheres was euthanized at 21 days after embolization. RESULTS With S97 microspheres, the vascular network had recovered to the preembolic state by 3 hours after embolization. With S98 microspheres, blood flow in the third-order branch had been restored in the same period. With S99 microspheres, the second- and lower order branches remained occluded until 21 days. Histopathologic specimens harvested at 3 hours revealed only a trace of PVA for S97 microspheres. With S98 microspheres, the vascular lumen was still found to be filled with PVA gel. With S99 microspheres, swollen microspheres densely filled the vascular lumen even on day 21. CONCLUSIONS Dissolution process in vitro and the duration of arterial occlusion in vivo were possibly related to the degree of saponification of PVA. This result may support feasibility of PVA microspheres as a temporary embolic agent.

Pancreatitis after transcatheter embolization of a splenic aneurysm

A 52-year-old woman was treated for a splenic aneurysm that was found on abdominal computed tomography (CT) during a preoperative assessment for rectal cancer. The aneurysm was embolized using the “double coil-delivered microcatheter technique,” and 4 ml of a mixture of N-butyl 2-cyanoacrylate (NBCA) and iodized oil (Lipiodol) (NBCA/Lipiodol = 1.0: 2.5) were injected into the aneurysm. The patient complained of left upper quadrant abdominal pain immediately after the procedure. A blood test 2 days after the procedure showed an increased white blood cell count (13 100/μl), C-reactive protein (13.36 mg/dl), and pancreatic amylase (428 U/l). Abdominal CT scan showed a huge cystic lesion at the pancreatic tail, in the center of which was a highly enhanced area due to accumulated NBCA-Lipiodol. Postembolization pancreatitis was diagnosed, and treatment with fasting and a drip infusion of nafamostat mesilate was started. The patient’s abdominal pain became less severe within 3 days, and the pancreatic enzyme level had normalized 14 days after treatment. On CT, the cystic lesion at the pancreatic tail was smaller 20 days after the procedure, and it had disappeared completely 75 days after the procedure.

Transcatheter coil embolization of an aneurysm of an anomalous splenic artery : Usefulness of double microcatheter method

Transcatheter embolization using two microcatheters of different shapes was performed to treat a 34-mm-diameter aneurysm that was located near the origin of a splenic artery that originated from the superior mesenteric artery (SMA). The procedure resulted in complete packing of the aneurysm and preserving splenic arterial blood flow.

Percutaneous translumbar inferior vena cava cannulation under computed tomography guidance

Percutaneous translumbar inferior vena cava (IVC) cannulation is an alternative approach for central venous catheterization, but there have been sporadic reports of puncture-related complications. To avoid complications during IVC puncture, percutaneous translumbar IVC cannulation was performed under computed tomography (CT) guidance in addition to fluoroscopy in two patients. To perform chemotherapy for recurrent breast cancer, we planned subcutaneous port catheter placement for central venous access. Under CT guidance, the direction and insertion distance of a long elastor needle were adjusted, and the IVC was punctured at the level of the third lumbar vertebra while taking care to avoid the right urinary tract. A guidewire was inserted through the long elastor needle, and a catheter was placed over the guidewire. It was possible to perform central venous catheterization by percutaneous translumbar inferior vena cava cannulation under CT guidance.

Improvement in respiratory function by percutaneous vertebroplasty

Background: Percutaneous vertebroplasty (PVP) improves back pain and corrects spinal misalignment to some extent, and thus may improve respiratory function. Purpose: To retrospectively investigate changes in respiratory function after PVP. Material and Methods: 41 patients (mean age 72.0 years, range 59–86 years; 39 women, two men) who had undergone PVP for vertebral compression fractures (37 thoracic vertebral bodies [Th6–Th12] and 50 lumbar vertebral bodies [L1–L5]) caused by osteoporosis visited our hospital for follow-up consultation between January and June 2005. At this follow-up consultation, respiratory function testing, including percent forced vital capacity (FVC%) and percent forced expiratory volume in 1 s (FEV1%), was performed. We retrospectively compared these values with those taken before PVP using a Wilcoxon signed-rank test. Results: FVC% was 85.2±30.3% before PVP and 91.5±16.8% at follow-up (mean 10 months after PVP), which represented a significant difference (P<0.003). No significant difference in FEV1% was detected. Regarding the number of treatment levels, that is, single vertebroplasty versus multiple vertebroplasty, no significant difference in improvement of FVC% was confirmed (P=0.1). FVC% was abnormally low (≤79%) before PVP in 16 patients and improved to within normal range postoperatively in six of these patients (38%). Conclusion: PVP improves preoperatively decreased lung function, but this improvement takes time.

Composite material stent comprising metallic wire and polylactic acid fibers, and its mechanical strength and retrievability

Background: Although metallic stents are characterized by strong expanse of force, thin walls, and easy stent deployment, their removal from the body is usually difficult or impossible due to the difficulty of unraveling their mesh structure. A stent built of a composite material comprising a metallic wire and a polylactic acid (PLA) fiber, in which the metallic wire component could be unraveled after PLA fiber degradation in the body, should allow easy stent removal. Purpose: To evaluate the mechanical strength and retrievability of a composite material stent comprising a metallic wire and a PLA fiber. Material and Methods: We produced a composite material stent comprising a metallic wire and a biodegradable fiber (hybrid stent). As the metallic wire is not cross-linked with itself, but with the PLA fibers only, the hybrid stent can be easily unraveled after PLA fiber degradation. This stent was built with a 0.2-mm stainless-steel wire and a 0.23-mm PLA fiber knitted in the same textile as an Ultraflex stent. For comparison, an identical stent was built using PLA fiber only (PLA stent). The mechanical strength of these stents was tested by the radial expansive force response against circumferential shrinkage stress load. Change in radial force due to PLA fiber degradation was estimated by adding an artificial PLA degeneration process, by immersing each stent in a water bath at 80°C for 48 hours. Retrievability of the hybrid stent after PLA degeneration was examined by hooking and pulling out the residual stainless-steel wire from a silicon tube. Results: The hybrid stent exhibited a linear response in radial expansive force within the range of 15% diameter reduction. The PLA stent did not exhibit linear response at over 15% diameter reduction. Decrease of radial expansive force after PLA degradation was within 5% of the original force in the hybrid stent, but the PLA stent did not create effective radial expansive force. Hybrid stents, even after PLA degradation, exhibited a linear response in radial expansive force, within the range of 15% diameter reduction. The metallic component of the heat-processed hybrid stent was easily unraveled by pulling out the wire. Conclusion: The hybrid stent comprising a stainless-steel wire and a PLA fiber appears to provide effective radial expansive force and retrievability.

Cerebral microembolisation during radiofrequency ablation of lung tumours: detection by carotid duplex ultrasound

The aim of this study was to investigate the appearance of microbubbles during radiofrequency ablation (RFA) of lung tumours. Eight consecutive patients (mean age, 73.1 years; 3 men and 5 women; 10 malignant lesions; mean lesion size, 24.8 mm) who underwent RFA of lung tumours using internally cooled single electrodes were enrolled. During the RFA procedure, the right internal carotid artery was continuously monitored by duplex ultrasound. High-intensity transient signals (HITS) that occurred in the Doppler blood flow waveform were taken to indicate microbubbles. 21 RFA applications were performed for the 10 lesions. HITS were observed in 19 of 21 RFA applications; the mean frequency in a single application was 10+/-13.3. A statistical correlation was seen between the duration of energy deposition and the number of HITS, and between tumour size and the number of HITS. Microbubbles were detected in all patients in the late phase of the first session of RFA.

Intraosseous Venography with Carbon Dioxide in Percutaneous Vertebroplasty: Carbon Dioxide Retention in Renal Veins

The objective of the present study was to determine the frequency of gas retention in the renal vein following carbon dioxide intraosseous venography in the prone position and, while citing references, to examine its onset mechanisms. All percutaneous vertebroplasties performed at our hospital from January to December 2005 were registered and retrospectively analyzed. Of 43 registered procedures treating 79 vertebrae, 28 procedures treating 54 vertebrae were analyzed. Vertebral intraosseous venography was performed using carbon dioxide as a contrast agent in all percutaneous vertebroplasty procedures. In preoperative and postoperative vertebral CT, gas retention in the renal vein and other areas was assessed. Preoperative CT did not show gas retention (0/28 procedures; 0%). Postoperative CT confirmed gas retention in the renal vein in 10 of the 28 procedures (35.7%). Gas retention was seen in the right renal vein in 8 procedures (28.6%), in the left renal vein in 5 procedures (17.9%), in the left and right renal veins in 3 procedures (10.7%), in vertebrae in 22 procedures (78.6%), in the soft tissue around vertebrae in 14 procedures (50.0%), in the spinal canal in 12 procedures (42.9%), and in the subcutaneous tissue in 5 procedures (17.9%). In conclusion, in our study, carbon dioxide gas injected into the vertebra frequently reached and remained in the renal vein.