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.

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.

High-flow priapism undergoing arterial embolization: review of literature following American Urological Association guideline on the management of priapism.

We report herein a case of a patient with high-flow priapism for whom a gelatin sponge was used as a temporary occlusive agent in arterial embolization, resulting in favorable outcome. The American Urological Association guideline on the management of priapism recommends using temporary occlusive agents. We reviewed all reports published after the introduction of this guideline to compare temporary and permanent occlusive agents in terms of symptom improvement and onset of erectile dysfunction. The rate of symptom improvement differed significantly between temporary and permanent embolizing materials, but no significant difference was apparent in the rate of erectile function improvement.

Relationship between cement distribution pattern and new compression fracture after percutaneous vertebroplasty.

OBJECTIVE: The objective of this study was to prospectively investigate relationships between cement distribution patterns and the occurrence rates of new compression fractures after percutaneous vertebroplasty. SUBJECTS AND METHODS: Percutaneous vertebroplasty was performed for osteoporotic compression fractures in 76 consecutive patients. Patients were divided into two groups according to the cement filling pattern shown on radiography and CT: cleft pattern group (group C, n = 34), compact and solid cement filling pattern in vertebrae; and trabecular pattern group (group T, n = 42), sponge-like filling pattern. A visual analog scale (VAS) was used to assess pain severity, and anterior and lateral radiographs of the thoracic and lumbar vertebrae were obtained 1-3 days and 1, 4, 10, 22, and 34 months after percutaneous vertebroplasty. Differences in treatment efficacy and the occurrence rates of new compression fractures were examined and compared for both groups using the Mann-Whitney U test and chi-square test. RESULTS: A significant difference was seen between groups with respect to the volume of cement injected per vertebra (mean volume: group C, 4.5 mL; group T, 3.7 mL; p = 0.01). VAS improvement did not differ significantly between group C (4.6) and group T (4.5). The mean follow-up period was 19.5 months, during which new compression fractures were significantly more frequent in group C (17 of 34 [50%]) than in group T (11 of 42 [26.2%]; p = 0.03). CONCLUSION: Although cement distribution patterns do not significantly affect initial clinical response, a higher incidence of new compression fractures is seen in patients with treated vertebrae exhibiting a cleft pattern.

A case of spontaneous regression of hepatocellular carcinoma with multiple lung metastases.

Spontaneous regression of hepatocellular carcinoma (HCC) is a rare phenomenon. We present herein the case of a patient with hepatocellular carcinoma with multiple lung metastases in whom malignancy spontaneously regressed after taking Pheliinus linteus Mycelium. A 79-year-old man consulted our hospital complaining of epigastric discomfort. Abdominal MRI and CT revealed a 3 cm diameter tumor in the liver, and chest CT showed numerous nodular lesions. The levels of alpha-fetoprotein (AFP) and protein induced by vitamin K deficiency or antagonist-II (PIVKA-II) were very high. We diagnosed HCC with multiple lung metastases, and no therapy was performed. Independently he took exact from Phellinus linteus Mycelium for one month, and 6 months later the tumors appeared to be in complete regression. The mechanism underlying this intriguing phenomenon remains unknown.

A new method for establishing an intrapulmonary tumor in the rabbit.

OBJECTIVES: Local treatments against malignant intrapulmonary tumors, such as radiotherapy, photodynamic therapy, and laser ablation therapy, are sometimes used in preference to surgery or chemotherapy. The efficacy of such treatments is dependent not only on the pathological type of the primary tumor, but also on loco-regional settings such as location of the lesion and relationship between the tumor and surrounding organs as well as tissues. Therefore, in order to evaluate the efficacy of a newly developed local treatment, it is essential to have a model in which a tumor can be established at an intended location. In this study, we developed a model for the establishment of an intrapulmonary tumor, using the rabbit. METHODS: After induction of general anaesthesia, a catheter was inserted via the airway into the lung of a Japanese white rabbit, under X-ray guidance. The lung was then inoculated with a collagen gel matrix containing a suspension of VX2 cells derived from rabbit skin squamous cell carcinoma. Subsequent tumor growth was evaluated with X-ray imaging and pathological examination. RESULTS: Growth of a solitary tumor at the target site was pathologically confirmed in 9 of 12 rabbits that were inoculated with 1 x 10(8) cells. In addition, tumor growth could be followed in 8 of 9 rabbits by chest X-ray examination. That is, a solitary intrapulmonary tumor could be established in 8 of 12 animals (67%). CONCLUSION: The rabbit model reported here enables establishment of a solitary intrapulmonary tumor and thus can provide a suitable experimental setting for evaluation of local treatments of intrapulmonary tumors.

Mechanical characteristics of composite knitted stents.

We used metal wires and fibers to fabricate a composite knitted stent and then compare the mechanical characteristics of this stent with those of a pure metallic stent of the same construction in order to develop a stent that offers a comparable degree of expandability as metallic stents but can be used for highly curved lesions that cannot be treated using metallic stents. We fabricated two types of composite knitted stent (N-Z stents), using nitinol wire with a diameter of 0.12 mm and polypara-phenylene-benzobisoxazole (PBO) multifilament fiber (Zyron AS; Toyobo, Osaka, Japan). Stents were knitted into a cylindrical shape using the same textile pattern as a Strecker stent. Two loop lengths (L) of nitinol wire were used in the N-Z stents: L = 1.84 mm (N-Z stent L = 1.84) and L = 2.08 mm (N-Z stent L = 2.08). For the sake of comparison, we fabricated a metallic stent of nitinol using the same textile pattern (N-N stent L = 1.92). We applied a radial compression force diametrically to each stent and applied a bending force diametrically at the free end of a stent with one end fixed in order to evaluate the relationship between stent elasticity and load values. In addition, we macroscopically evaluated the generation of kinks when the stent was bent 180 degrees . The radial compressive force when the stent diameter was reduced by 53% was 6.44 N in the case of N-Z stent L = 1.84, 6.14 N in the case of N-Z stent L = 2.08, and 4.96 N in the case of N-N stent L = 1.92 mm. The composite stent had a radial compressive force higher than that of a metallic stent. The restoring force to longitudinal direction at a 90 degrees bending angle was 0.005 N for N-Z stent L = 1.84, 0.003 N for N-Z stent L = 2.08, and 0.034 N for N-N stent L = 1.92. The restoring force of the composite stent was significantly lower. Finally, the composite stent generated no definitive kinks at a bending angle of 180 degrees , regardless of loop length. However, the N-N stent clearly produced kinks, causing blockage of the inner cavity. In conclusion, the use of a metal and fiber composite in the construction of a knitted stent ensures an expansion performance comparable to that of metallic stents, while providing better kink resistance.

Peripheral stent placement in hemodialysis grafts.

The purpose of the present study was to evaluate the clinical outcome of peripheral stent placement after failed balloon angioplasty in patients with grafts who are on hemodialysis. We examined 30 Wallstents that were placed in 26 patients because balloon angioplasty failed or early restenosis (<3 months) occurred within 3 months. We retrospectively reviewed 267 consecutive balloon angioplasties performed in 71 patients with graft access between August 2000 and March 2007. Stent placements accounted for 30 (11.2%) of the 267 balloon angioplasties. The clinical success rate of stent placement was 93.3% (28 of 30 stent placements). The 3-, 6-, and 12-month primary patency rates were 73.3%, 39.3%, and 17.7%, respectively. The 1-, 2-, and 3-year secondary patency rates were 90.2%, 83.8%, and 83.8%, respectively. Primary patency was significantly prolonged by stent placement after early restenosis compared with previous balloon angioplasty alone (P = 0.0059). Primary patency after stent placement was significantly lower than after successful balloon angioplasty without indications for stent placement (P = 0.0279). Secondary patency rates did not significantly differ between stent placement and balloon angioplasty alone. The mean number of reinterventions required to maintain secondary patency after stent placement was significantly larger than that after balloon angioplasty alone (Mann-Whitney U test, P = 0.0419). We concluded that peripheral stent placement for graft access is effective for salvaging vascular access after failed balloon angioplasty and for prolonging patency in early restenosis after balloon angioplasty. However, reinterventions are required to maintain secondary patency after stent placement. Furthermore, peripheral stent placement for graft access cannot achieve the same primary patency as balloon angioplasty alone.

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.

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.

Biochemical markers of bone turnover in percutaneous vertebroplasty for osteoporotic compression fracture.

PURPOSE: To evaluate relationships between biochemical markers of bone turnover, bone mineral density, and new compression fractures following vertebroplasty. METHODS: Initially, we enrolled 30 consecutive patients with vertebral compression fractures caused by osteoporosis. Twenty-three of the 30 patients visited our hospital for follow-up examinations for more than 4 weeks after vertebroplasty. The patients were divided into two groups: patients with new fractures (group F) and patients with no new fractures (group N). We analyzed differences in the following parameters between these two groups: serum bone alkaline phosphatase, urinary crosslinked N-telopeptide of type I collagen, urinary deoxypyridinoline, and bone mineral density. Next, the patients were divided into another two groups: patients with higher risk (group H: urinary crosslinked N-telopeptide of type I collagen >54.3 nmol BCE/mmol Cr or urinary deoxypyridinoline >7.6 nmol/mmol Cr, and serum bone alkaline phosphatase <29.0 U/l) and patients with lower risk (group L). We analyzed the difference in the rate of new fractures between these two groups. RESULTS: We identified 9 new fractures in 7 patients. There were no significant differences between groups F and N. We identified 5 new fractures in 3 of the 4 patients in group H, and 4 new fractures in 4 of the 19 patients in group L. There was a significant difference in the rate of new fractures between groups H and L. CONCLUSIONS: A combination of high levels of bone resorption markers and normal levels of bone formation markers may be associated with increased risk of new recurrent fractures after percutaneous vertebroplasty.

Primary patency with cutting and conventional balloon angioplasty for different types of hemodialysis access stenosis.

PURPOSE: To compare primary patency rates of cutting balloon percutaneous transluminal angioplasty (PTA) (hereafter, cutting PTA) and conventional balloon PTA (hereafter, conventional PTA) in the treatment of different types of hemodialysis access stenosis. MATERIALS AND METHODS: The institutional review board approved this study. Written informed consent was obtained for the prospective component of this study and waived for the retrospective component. Patients in whom treatment with cutting PTA alone or conventional PTA alone was clinically successful formed the two study groups. Primary patency for the lesion was defined as uninterrupted patency of the treated site after balloon PTA. A site was no longer considered patent when the patient underwent treatment for hemodialysis access failure due to restenosis of the treated site. Primary patency rates for lesions were calculated with the Kaplan-Meier method according to the type of stenosis. We compared the two groups by using the log-rank test to determine statistical significance. RESULTS: In the cutting PTA group, 62 patients with 77 stenoses (32 men, 30 women; mean age, 65.5 years +/- 10.1 [standard deviation]) achieved clinical success. In the conventional PTA group, 52 patients with 68 stenoses (23 men, 29 women; mean age, 61.9 years +/- 10.2) achieved clinical success. In patients with autogenous venous stenosis, no significant difference in the primary patency rate was noted between groups (P = .369). In patients with graft-to-vein anastomotic stenosis, the primary patency rate was significantly higher for cutting PTA than for conventional PTA (P = .39). In patients with intragraft stenosis, no significant difference in the primary patency rate was noted between groups (P = .379). In patients with in-stent restenosis, no significant difference in the primary patency rate was noted between groups (P = .923). CONCLUSION: Primary patency rates are significantly higher for cutting PTA in the treatment of graft-to-vein anastomotic stenosis; however, no significant differences in primary patency rates exist between these PTAs in the treatment of autogenous venous stenosis, intragraft stenosis, or in-stent restenosis.

Radiological follow-up of new compression fractures following percutaneous vertebroplasty.

The purpose of the present study was to ascertain chronological changes in the analgesic effects of percutaneous vertebroplasty (PVP) on osteoporotic vertebral compression fractures and to radiologically follow new compression fractures after PVP. Seventy-six patients (206 vertebral bodies) were followed radiologically for a mean of 11.5 months. A visual analog scale (VAS; 0-10) was used to assess pain severity, and frontal and lateral plain radiographs of the thoracic and lumbar vertebrae were taken 1-3 days and 1, 4, 10, and 22 months after PVP. The average VAS score was 7.2 +/- 2.0 (mean pain score +/- standard deviation) before PVP, 2.5 +/- 2.3 at 1-3 days after PVP, 2.2 +/- 2.3 at 1 month, 1.9 +/- 2.2 at 4 months, 1.8 +/- 2.4 at 10 months, and 1.0 +/- 0.2 at 22 months. A new compression fracture was confirmed in 56 vertebral bodies in 28 patients (36.8%), affecting 38 adjacent vertebral bodies (67.8%), 17 nonadjacent vertebral bodies (30.4%), and 1 treated vertebral body (1.8%). A new compression fracture occurred within 1 week of PVP in 2 vertebral bodies (3.6%), between 1 week and 1 month after PVP in 22 (39.3%), between 1 and 3 months in 12 (21.4%), between 3 and 6 months in 12 (21.4%), and after more than 6 months in 8 (14.3%). PVP was highly effective in relieving the pain associated with osteoporosis-induced vertebral compression fractures, and this analgesia was long lasting. Radiological follow-up observation revealed new compression fractures in about one-third of patients. More than half of these new compression fractures occurred in adjacent vertebral bodies within 3 months of PVP.

Percutaneous vertebroplasty for osteoporotic compression fracture: multivariate study of predictors of new vertebral body fracture.

PURPOSE: To investigate the risk factors and relative risk of new compression fractures following vertebroplasty. METHODS: Initially, we enrolled 104 consecutive patients with vertebral compression fractures caused by osteoporosis. A total of 83 of the 104 patients visited our hospital for follow-up examinations for more than 4 weeks after vertebroplasty. Logistic regression analysis of the data obtained from these 83 patients was used to determine relative risks of recurrent compression fractures, using 13 different factors. RESULTS: We identified 59 new fractures in 30 of the 83 patients: 41 new fractures in vertebrae adjacent to treated vertebrae; and 18 new fractures in vertebrae not adjacent to treated vertebrae. New fractures occurred in vertebrae adjacent to treated vertebrae significantly more frequently than in vertebrae not adjacent to treated vertebrae. Only cement leakage into the disk was a significant predictor of new vertebral body fracture after vertebroplasty (odds ratio = 4.633). None of the following covariates were associated with increased risk of new fracture: age, gender, bone mineral density, the number of vertebroplasty procedures, the number of vertebrae treated per procedure, the cumulative number of vertebrae treated, the presence of a single untreated vertebra between treated vertebrae, the presence of multiple untreated vertebrae between treated vertebrae, the amount of bone cement injected per procedure, the cumulative amount of bone cement injected, cement leakage into the soft tissue around the vertebra, and cement leakage into the vein.

Clinical assessment of percutaneous radiofrequency ablation for painful metastatic bone tumors.

PURPOSE: To investigate the pain-alleviating effects of radiofrequency ablation (RFA) on metastatic bone tumors in relation to tumor size, combined therapy, and percent tumor necrosis rate following RFA. METHODS: Subjects comprised 24 patients with 28 painful metastatic bone tumors. A 17G internally cooled electrode was inserted into the tumor for CT guidance and ablation was performed. Bone cement was injected following RFA for 4 tumors involving a weight-bearing bone, while 5 tumors were treated using combined RFA and external irradiation. Percent necrosis rate of the tumor was measured using contrast-enhanced computed tomography 1 week after RFA. RESULTS: Improvement in the visual analog scale (VAS) score was 4.6 +/- 2.2 for large tumors (> 5 cm, n = 12), 3.7 +/- 1.8 for medium-sized tumors (3.1-5.0 cm, n = 11), and 3.5 +/- 1.7 for small tumors (< or = 3 cm, n = 4), with no significant differences noted among tumor sizes. Improvement in the VAS score was 3.5 +/- 1.3 for the 4 tumors in the RFA + bone cement group, 3.2 +/- 1.9 for the 5 tumors in the RFA + radiation therapy group, and 4.8 +/- 2.2 for the 18 tumors in the RFA group. No significant differences were identified between groups. The improvement in the VAS score was 3.8 +/- 2.3, 4.0 +/- 1.9, and 4.7 +/- 2.6 in patients with tumor necrosis rates of 0-49%, 50-74%, and 75-100%, respectively. No significant association was observed among these three groups. CONCLUSION: Percutaneous RFA therapy was effective in relieving pain due to metastatic bone tumors. No relationships appear to exist between initial response and tumor size, combined therapy, and percent tumor necrosis.

Percutaneous vertebroplasty: relationship between vertebral body bone marrow edema pattern on MR images and initial clinical response.

PURPOSE: To prospectively investigate the relationship between initial clinical response and bone marrow edema pattern on preprocedural magnetic resonance (MR) images in vertebral bodies selected for percutaneous vertebroplasty (PVP). MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. PVP was performed for osteoporotic compression fractures in 80 consecutive patients (mean age, 72.4 years; range, 44-85 years; 67 women and 14 men; 157 vertebrae). Patients were divided into three groups according to the proportion of the vertebra in which the bone marrow edema pattern was observed on sagittal MR images: group 1, 50% or more of the vertebra; group 2, less than 50%; group 3, no edema pattern observed. By using Wilcoxon rank sum test, Fisher exact test, and Wilcoxon signed rank test, groups were examined for differences in treatment efficacy, which was defined as the difference between preprocedural and postprocedural pain as assessed by means of visual analog scale (VAS) score at 1-3 days after PVP. RESULTS: Forty-four patients were assigned to group 1, 14 to group 2, and 22 to group 3. No significant difference was seen between the groups with respect to age, sex, number of treated vertebrae, or preprocedural VAS score. In group 1, VAS score decreased from 7.5 before the procedure to 2.9 after (improvement of 4.6). In group 2, the score decreased from 6.8 to 3.1 (improvement of 3.7). In group 3, the score decreased from 7.0 to 4.3 (improvement of 2.7). Improvement was significantly greater in group 1 than in group 3 (P < .005). CONCLUSION: PVP resulted in significantly greater clinical improvement in patients with an extensive bone marrow edema pattern than in those without this pattern. (c) RSNA, 2006.

Radiation exposure to operators during vertebroplasty.

PURPOSE: To measure the radiation received by physicians during percutaneous vertebroplasty with use of two types of injection devices with the interventional equipment guided by computed tomography (CT) and an angiographic/CT system. MATERIALS AND METHODS: Twenty consecutive patients who underwent percutaneous vertebroplasty were included in this study. The patients were divided into two groups, the 1-mL syringe group and the bone cement injector group. Percutaneous vertebroplasties were performed with the IVR-CT system, which combines angiographic and CT equipment with a single fluoroscopy table. Radiation dose to operators was measured as equivalent dose penetrating at a 10-mm tissue depth with use of electronic personal dosimeters attached outside and inside lead aprons. Effective radiation dose (HE) was estimated based on the radiation dose outside the lead apron (Ha) and the radiation dose inside the lead apron (Hb). Differences between the groups in doses and fluoroscopic duration were analyzed. RESULTS: In the 1-mL syringe group and bone cement injector group, mean Ha measurements were 320.8 microSv and 116.2 microSv, respectively. Mean Hb measurements were 14.5 microSv versus 7.8 microSv and mean HE measurements were 48.2 microSv versus 19.7 microSv. Significant differences were found in Ha, Hb, and HE. However, duration of fluoroscopy did not differ significantly between groups. CONCLUSIONS: Radiation dose was relatively high for operators performing percutaneous vertebroplasty. The bone cement injector was useful in reducing the level of radiation exposure to operators during vertebroplasty.

Radiofrequency ablation combined with CO2 injection for treatment of retroperitoneal tumor: protecting surrounding organs against thermal injury.

OBJECTIVE: The objective of this study was to separate target tumors from adjacent structures by injecting carbon dioxide (CO2) around the tumor to avoid thermal injury and the heat-sink effect from the blood vessel during percutaneous radiofrequency ablation. CONCLUSION: We successfully achieved complete ablation of a retroperitoneal tumor without thermal injury. Imaging-guided percutaneous CO2 injection is useful for preventing thermal injury while achieving complete ablation of the tumor during radiofrequency ablation.

A new bioabsorbable sleeve for staple-line reinforcement: report of a clinical experience.

PURPOSE: The most frequent and troublesome complication after resection of an emphysematous lung is persistent air leakage. This report describes our recent experience of using sleeves made of polyglycolic acid to reinforce staple-lines to reduce air leaks after resection of emphysematous lung. METHODS: We used bioabsorbable sleeves made of polyglycolic acid (PGA) for staple-line reinforcement during lung resections in 25 patients with emphysema. RESULTS: Immediately after stapling, no air leaks were detected in 20 patients (80%), although prolonged air leaks lasting for more than 7 days were observed in three patients (12.5%). CONCLUSION: PGA sleeves do not constitute a foreign body that stays in the host lung, and they require no rinsing at the time of clinical use. Therefore, the PGA sleeve could be a promising new material instead of non-absorbable materials and xenomaterials for staple-line reinforcement.