Outer Cannula Research Articles

Percutaneous extraction of deeply-embedded radiopaque foreign bodies using a less-invasive technique under image guidance

Radiopaque foreign bodies (RFBs) retained in soft tissue are a common clinical problem. Image-guided extraction plays a great role in this realm. We describe our experience in the management of RFBs imbedded deeply in soft tissue using a percutaneous less-invasive technique under fluoroscopic guidance. In all, 76 patients with 251 RFBs including gun pellets (n = 223), needle fragments (n = 4), and irregular metallic splinters (n = 24) underwent percutaneous extraction of RFBs with the modified technique, which consists of: (1) percutaneously gaining access to the RFB using an 18-gauge needle, several tapered dilators, and an outer cannula and (2) grasping and withdrawal of RFB using a forceps through the cannula. The following periods were 6 months to 6 years. The direct distance between RFB and skin was from 2.5 cm to 8.5 cm (average 4.8 cm). Every RFB was successfully removed with technique success rate of 100%. The RFBs measured 0.2 cm to 3.0 cm in length and 0.1 cm to 0.5 cm in width. The procedural time and exposure time of X-ray for each RFB extraction were 8 minutes to 15 minutes and 1 minute to 4 minutes (mean, 10 minutes and 2 minutes, respectively). The radiation doses for each RFB and patient were 15.64 mGy to 62.56 mGy and 15.64 mGy to 500.48 mGy (mean, 30.26 mGy and 72.47 mGy, respectively). Blood lead concentration decreased to normal one month after the procedures in four patients with preprocedural high level. No complications were observed during the procedures and the following periods. Percutaneous extraction of RFBs from deep soft tissue with the present technique is safe, effective, and minimally invasive.

CT-guided radiofrequency liver tumour ablation: use of a two-step coaxial system with a fine guide needle wire unit for high-risk cases

Accurate radiofrequency (RF) needle targeting to liver lesions under CT guidance is technically difficult and generally requires multiple needle manipulations, which carries potential risk. This approach is hardly applicable for precariously located lesions or for patients who have difficulty holding their breath. The aim of this study was to develop a novel two-step coaxial system to facilitate CT-guided RF ablation in difficult cases. The study group comprised 11 patients with 12 hepatic lesions. The coaxial system consisted of two parts: a 21-gauge pencil-tip guide needle wire (GNW) unit comprising a 150-mm-long needle segment and a 250-mm-long wire segment; and a 140-mm-long outer cannula with its stylet, which accepts a 17-gauge RF electrode needle. The GNW was inserted until the route of the GNW was confirmed to be positioned correctly. The cannula with the stylet was then advanced along the GNW. Lesions were successfully accessed using the GNW, even in patients who could not hold their breath, and manipulation was feasible within the limited space of the CT gantry. The light GNW also facilitated step-by-step CT-guided angular manipulations, unlike heavy RF electrodes, which are unstable during hands-free use unless deeply inserted. Therefore, this system enabled sequential ablations of large tumours by ensuring three different routes in advance by using the GNW. Insertion of the cannula along the GNW was simple. In conclusion, the two-step coaxial system enabled CT-guided RF tumour ablation to be performed in cases conventionally contraindicated owing to high risk of serious complications.

Cuffed Inner Cannula and Flexible Outer Cannula Trachesotomy Device: Ensuring a Stable Airway

Tracheostomy tubes (TTs) are used to provide a direct airway to a patient’s trachea when natural respiration is no longer possible. A TT generally includes an elongate outer cannula as well as a smaller inner cannula formed so as to have a gradual curve to facilitate insertion into a patient’s trachea. In order seal the airway around the tube, a conventional TT generally has an inflatable cuff attached to the perimeter of the outer cannula. When inflated, the cuff seals the airway around the cannula, thereby, requiring air to pass through only the cannula. In order to retain the distal end of the device in its operative position, the TT generally includes a neck plate or other fixation device, which is attached to the proximal end of the outer cannula. There are many potential drawbacks with current TTs, which can range in effect from minor irritation to death. Varying sizes of individuals and differences in anatomical dimensions leads to discomfort from TTs that fit poorly. The rigid ends of the outer cannula often put pressure on the walls of the trachea, which can cause irritation and ulceration. Cuffed inner cannulas are required to be replaced with uncuffed inner cannulas as soon as possible, after placement, to avoid pressure necrosis and allow for vocalization. The process of switching TTs may also be very hazardous, especially when treating obese patients. The stoma can easily be lost among layers of fat and skin, as well as the trachea, which all move independently of one another. Losing the stoma may cause suffocation and possibly death. Our novel device is a TT for use with a neck plate having an aperture. The TT comprises an elongate outer cannula having a lumen and configured to extend through the aperture. An elongate inner cannula having a lumen and an inflatable cuff and configured to extend through the lumen of the outer cannula such that the cuff extends beyond a distal end of the outer cannula and an interlocking mechanism configured to releasably secure a proximal end of the inner cannula to a proximal end of the outer cannula. This superior TT has the potential for wide application with a special emphasis on application within the obese population. Such patients experience the most difficulty with current devices. There is no single device in the market today that packages the numerous features of this particular design.

Characterization of Precurved Needles for Use in Distal Tip Manipulation Mechanisms

Precurved needles are used in a variety of medical applications for both passive and active control of instrument position. In one application, the deployment of a precurved stylet from a concentric outer cannula can be used to achieve lateral positioning of the distal tip of the stylet. This paper outlines how the material and geometry of the stylet can be chosen to ensure that it will not yield and thus repeatedly return to its precurved shape when deployed from a cannula. Using this methodology, we calculate the maximum strain for a range of stylet geometries and show that nitinol is required for the stylet material so that it will not plastically deform. Then, 16 stylets of varying diameters (0.508 mm, 0.635 mm, 0.838 mm, and 0.990 mm) and radii of curvature (10 mm, 20 mm, 30 mm, and 40 mm) were manufactured. Experiments were performed with four different diameter cannulas (20, 18, 16, and 14 gauges) to measure the forces required to deploy the stylets from and retract them back inside the cannulas. Retraction forces were measured between 0.3 N and 13.9 N, and deployment forces were measured between 0.2 N and 7.0 N. For a given cannula, it was found that force increases as the stylet diameter increases and as the bend radius decreases.

Wang-Zwische Double Lumen Cannula—Toward a Percutaneous and Ambulatory Paracorporeal Artificial Lung

We are developing a high performance double lumen cannula (DLC) for a minimally invasive, ambulatory and percutaneous paracorporeal artificial lung (PAL). The Wang-Zwische (W-Z) DLC was designed for percutaneous insertion into the Internal Jugular (IJ) vein with a drainage lumen open to both the superior vena cava (SVC) and the inferior vena cava (IVC) maximizing venous drainage. A separate collapsible but nondistensible membrane infusion lumen open to the right atrium (RA) achieves minimal recirculation allowing for total gas exchange. The W-Z DLC prototypes are made by a proprietary dip molding process with the "molded in" flat wire spiral stainless steel spring resulting in a flexible yet kink resistant thin wall (0.1 mm) outer cannula with one piece construction. With the ultra thin membrane infusion lumen collapsed, an introducer shaft fits tightly within the drainage lumen to facilitate insertion with placement at the SVC-RA-IVC junction. The W-Z DLC prototypes were tested while connected to a compact pump-gas exchanger circuit in three sheep (2 acute and one 15 day performance study). Insertion was simple, using standard percutaneous insertion techniques. Recirculation was as low as 2%. The 15 day performance study demonstrated our prototype 26 Fr W-Z DLC can achieve 2 L/min blood flow with minimal recirculation. The W-Z DLC design minimizes recirculation rate, maximizes flow lumen cross-sectional area, and maximizes achievable blood flow to enhance gas exchange performance allowing for one site percutaneous venovenous support.

Bone cement used as an embolic agent for active bleeding in vertebroplasty of metastatic lesions

We treated two cases of bleeding by injecting bone cement into tumor-feeding vessels of metastatic hypervascular tumors during a percutaneous vertebroplasty (PV) procedure. When the inner needle was pulled out after puncture of the metastatic vertebral tumor, active arterial bleeding from the outer needle cannula was noticed. Bleeding was not stopped by injection of Gelfoam particles through the cannula. Thus, bone cement was injected, which filled the tumor-feeding vessels, and bleeding stopped. Skin rash and high fever occurred 2-3 hours after the PV procedure, probably due to allergic reaction and massive tumor necrosis. To decrease the risk of active bleeding during PV for hypervascular bone metastases, arterial embolization of the feeding arteries should be performed 1 or 2 days prior to PV. If active bleeding occurs through the outer needle when performing PV, injection of bone cement after confirmation of bleeding from the tumor feeding vessels by vertebrography is effective.

Biphasic Finite Element Model of Solute Transport for Direct Infusion into Nervous Tissue

Infusion-based techniques are promising drug delivery methods for treating diseases of the nervous system. Direct infusion into tissue parenchyma circumvents the blood-brain barrier, localizes delivery, and facilitates transport of macromolecular agents. Computational models that predict interstitial flow and solute transport may aid in protocol design and optimization. We have developed a biphasic finite element (FE) model that accounts for local, flow-induced tissue swelling around an infusion cavity. It solves for interstitial fluid flow, tissue deformation, and solute transport in surrounding isotropic gray matter. FE solutions for pressure-controlled infusion were validated by comparing with analytical solutions. The influence of deformation-dependent hydraulic permeability was considered. A transient, nonlinear relationship between infusion pressure and infusion rate was determined. The sensitivity of convection-dominated solute transport (i.e., albumin) over a range of nervous tissue properties was also simulated. Solute transport was found to be sensitive to pressure-induced swelling effects mainly in regions adjacent to the infusion cavity (r/a 0 <or= 5 where a 0 is the outer cannula radius) for short times infusion simulated (3 min). Overall, the biphasic approach predicted enhanced macromolecular transport for small volume infusions (e.g., 2 microL over 1 h). Solute transport was enhanced by decreasing Young's modulus and increasing hydraulic permeability of the tissue.

Poster 237: Single Puncture Arthroscopic Surgery Using a Ho-YAG Laser for TMJ Internal Derangement

We have developed an outer cannula for a temporomandibular joint (TMJ) arthroscope by attaching an additional treatment channel for Ho-YAG Laser surgery. This cannula makes it possible to access an intraarticular fibrous adhesion with a single puncture even in the small pathological joint space. We sought to evaluate the efficacy of this single puncture TMJ arthroscopic surgery using a Ho-YAG Laser.

口腔粘膜疾患の診断のための接触拡大粘膜鏡視検査法の開発

We developed a contact oral mucoscope for magnified observation of the oral mucosa and visualized subtle patterns of mucous lesions and subsurface mucous structures that are not normally visible with the naked eye.The oral mucosa was initially observed with the naked eye, and then examined by oral mucoscopy using either the non-contact or the contact technique. In the latter procedure, the contact glass plate of the outer cannula comes in contact with the lesion via linkage fluid. The non-contact technique consists of magnifying the oral mucosa using the outer cannula without the contact glass plate.We visualized numerous morphological features of the oral mucosa using the contact mucoscope, except the anterior upper process palatally, and anterior lower alveolar process lingually.The results suggested that the contact mucoscope is a non-invasive, diagnostic tool that can visualize subtle clinical patterns of oral mucosal lesions and subsurface oral mucosa, which are not normally visible with the naked eye.

Technical Note: Improved technique for fitting pigs with steered ileocecal valve cannulas1,2

Collection of ileal digesta to evaluate AA digestibilities has become increasingly important in swine nutrition research. Steered ileocecal valve cannulation of pigs permits total collection of ileal digesta, while still allowing normal digesta flow during noncollection periods. This technique was modified and used with 64 crossbred barrows in five trials. Our procedural changes included preoperative i.v. administration of a broad-spectrum antibiotic and nonsteroidal antiinflammatory drug, sharp incision through the muscle layers of the laparotomy wound, use of a heparinized saline lavage solution, replacement of the guide ring with a stylette, and fixing the outer cannula barrel in place with a hose clamp. The current technique involves a right flank laparotomy, parallel and distal to the last rib, with the pig under general anesthesia. A stainless-steel ring (inner ring = 2.0 mm thick, 35.0 mm i.d.) is introduced into the ileal lumen through an enterotomy proximal to the origin of the ileocecal fold. A nylon string attached to this ring is threaded through the ileum and ileocecal valve into the cecum using a silastic stylette, which encases the string. A second stainless-steel ring (outer ring = 2.0 mm thick, 34 mm o.d.) is fixed in place around the ileum, distal to the inner ring and just proximal to the ileocecal valve. A polyurethane cannula barrel (barrel = 100 mm long, 26 mm i.d., 32 mm o.d.; flange = 70 mm o.d.) is introduced into the cecal lumen via an enterotomy through the lateral cecal band and secured in place with two purse-string sutures. The cannula is exteriorized through an incision caudal and proximal to the intial laparotomy site, where it is plugged using a cylindrical stopper (26 mm o.d., 55 mm long) and held in place by a second cannula barrel (barrel = 43 mm length, 33 mm i.d., 41 mm o.d.; flange = 80 mm o.d.). Procedural changes decreased postsurgical complications, as evidenced by decreased seepage around the cannula and fewer and less severe adhesions noted at necropsy. Based on five trials, this technique is a reliable means of collecting ileal digesta for nutrient analyses.

Emphysema and Pneumothorax After Percutaneous Tracheostomy: Case Reports and an Anatomic Study

Part 1: To describe cases of emphysema (subcutaneous and/or mediastinal) and pneumothorax after percutaneous dilational tracheostomy (PDT) in a series of 326 patients, and to review the existing literature describing the incidence and possible mechanisms. Part 2: To analyze the potential mechanisms for the development of emphysema and pneumothorax in human cadaver models. A retrospective analysis of PDTs, in combination with an anatomic study in human cadavers. Part 1: All ICU patients who underwent PDT between 1997 and 2002 were enrolled in the study. We analyzed the cases of emphysema and pneumothorax. Similar cases were retrieved from the literature and underwent a systematic review. Part 2: The relevant anatomic structures were studied. We simulated the clinical situation after PDT in a human pathologic study in order to induce subcutaneous emphysema and pneumothorax. Part 1: Five cases of subcutaneous emphysema (1.5%) and two cases of pneumothorax (0.6%) are described. In the literature search, we found 41 cases of emphysema (1.4%) and 25 cases of pneumothorax (0.8%) in a total of 3,012 patients. Part 2: Subcutaneous emphysema could easily be induced in a human cadaver model by inflating air in the pretracheal tissues and after posterior tracheal wall laceration. Air leakage was also possible through a fenestrated cannula via the space between the inner nonfenestrated cannula and outer cannula and then through the fenestration. We conclude that one mechanism for the development of emphysema is an imperfect positioning of the fenestrated cannula, whereby the fenestration is extraluminal. For this reason, fenestrated cannulas should not be used immediately after placement of a PDT. Posterior tracheal wall laceration is another mechanism responsible for emphysema after PDT. After perforation of the posterior tracheal wall, the pleural space can be reached easily. This may result in a pneumothorax.

Image-guided 25-gauge needle biopsy for thoracic lesions: diagnostic feasibility and safety.

To report our experience regarding the feasibility and safety of 25-gauge needles for biopsy of thoracic lesions. Twenty-six patients with thoracic lesions, predominately pulmonary nodules, measuring 0.7-5.2 cm (mean, 1.6 cm) underwent biopsy with computed tomographic (n = 24), ultrasonographic (n = 1), or fluoroscopic (n = 1) guidance. Nineteen patients had severe chronic obstructive pulmonary disease (COPD), one had severe restrictive lung disease, and one had a coagulopathy; the other five patients had nonpulmonary primary tumors. Biopsy with an inner 25-gauge needle traversing an outer extrapleural coaxial cannula was performed in all patients. Cytologic quick staining was performed routinely to determine specimen adequacy and to establish a preliminary diagnosis. Complications, specimen adequacy, and need for larger specimens were evaluated. Adequate specimens (as determined by cytopathologists) were obtained in 24 (92%) of 26 patients, with a definitive diagnosis achieved in 23 (88%) patients during initial quick staining (17 malignant and six benign diagnoses). Two cases initially considered suspicious for malignancy were reclassified as benign (thymoma and histoplasmosis). At the request of cytopathologists, a larger needle was used to supplement the 25-gauge needle in six patients: In one patient, it provided further diagnostic information; in four, it did not; and in one, it confirmed non-Hodgkin lymphoma. Five patients developed a small pneumothorax (<10%) with use of the 25-gauge needle alone; one other patient, in whom larger needles were placed, received a radiologic chest catheter to evacuate the pneumothorax, thereby allowing the biopsy to continue. Image-guided 25-gauge needle biopsy is both feasible and safe.

Magnetic resonance-guided transcortical biopsy of bone marrow lesions using a magnetic resonance imaging-compatible piezoelectric power drill: preliminary experience.

To test utility and specific properties of a commercially available MRI compatible power drill for MR guided transcortical bone biopsy. In 17 patients MR-guided bone biopsy was performed in an open low-field scanner (0.2 T), using a piezoelectrically powered drilling machine. Target lesions were osteoblastic in four and nonsclerosed intramedullary in 13 cases. Titanium drills sized 3 to 4 mm and an outer cannula were coaxially used for power assisted cortical trephination. For intramedullary lesion sampling, spring loaded biopsy guns and sharpened cannulas were additionally applied in seven and fluid aspiration in two patients, respectively. The piezoelectric device proved to be fully MR compatible. Trephination and subsequent biopsy was successful in all patients without major complications. The drilling procedure could entirely be performed inside the magnet in case of a lateral approach (n = 11). The net drilling time averaged 7.8 minutes for trephination of nonimpaired diaphyseal bone, but was up to 50 minutes in case of thickened femoral bone. Procedures were complicated by frequent drill loosening, drill obstruction by cortical bone (n = 4) and impaired periosteal grip (n = 5) with damage to the outer cannula (n = 3). The piezoelectric power drill can be applied safely in a low-field MRI environment and is a valuable tool to facilitate transcortical bone biopsy.

Demonstration of low flow push–pull perfusion

Methods to follow in vivo chemical composition provide information regarding the processes of intercellular communication. There is a need for methods that provide chemical information from small volumes of the central nervous system (CNS) without sacrificing neurochemical recovery. One method that offers potential for providing such information is push–pull perfusion. In this study a low flow push–pull perfusion system is introduced that provides high (70–80%) in vitro recoveries. A concentric probe design is used with a 27-gauge stainless steel outer cannula for saline infusion and an inner fused silica capillary for fluid withdrawal. Flow rates of 10–50 nl/min were reliably generated and were well matched in vitro. Sampling was performed in the striatum of an anesthetized rat generating a 0.5 μl sample every 12 min. Capillary electrophoresis was used to determine glutamate levels in each sample; the basal level was found to be 1.97±0.70 μM. The method described was also demonstrated to deliver l- trans-pyrrolidine-2,4-dicarboxylic acid through the perfusion solution while sampling. Post-sampling histological analysis demonstrates little tissue disturbance to the sampled region. These data provide evidence that low flow push–pull method is a viable alternative for studying neurochemical signaling in the CNS.

A new core-biopsy instrument with an end-cut technique provides prostate biopsies with increased tissue yield.

To evaluate the tissue yield of a new core-biopsy needle with an end-cut mechanism when used for transrectal prostate biopsies. The end-cut instrument has an adjustable stroke length (13, 23 or 33 mm) and an inner and an outer cannula, but no trocar. It was compared with the conventional side-notch needle (Biopty, Bard, Covington, GA, USA) with trocar and fixed stroke length (22 mm). In 60 men, octant biopsies were taken including the apex, mid-medial, mid-lateral and basal positions. At random, the left side of the prostate was biopsied with one of the instruments and the right side with the other. The length and weight of the biopsy specimens were measured. In 40 men, the stroke length of the end-cut instrument was set to 23 mm, and in 20 men it was set to 33 mm. The weight and the weight per length of the biopsies provided by the end-cut instrument with a stroke length of 23 mm were 18.4% and 13.7%, respectively, greater than in the biopsies from the side-notch instrument (P<0.001). In 21.9% of the attempts no tissue was obtained by the end-cut needle, compared with 1.9% with the side-notch needle. With a 33 mm stroke length, the length and weight of the end-cut biopsies were 38.4% and 33.0%, respectively, greater than in biopsies from the side-notch instrument. The end-cut instrument provided a greater tissue yield than the side-notch needle, but a significant number of biopsies were lost.

Behaviour of the 2.1-mm (14 G) automated biopsy needle in phantoms

To study the behaviour of the 2.1-mm (14 G) core biopsy needle in targets of different consistencies and to correlate the needle behaviour to lengths of the samples. A series of butter blocks at temperatures of -5 degrees C, -2 degrees C, +1 degrees C, +4 degrees C, +7 degrees C, +10 degrees C, +13 degrees C, +16 degrees C and +19 degrees C simulating lesions of different hardness in human breast, were passed with needles (3 passes at each temperature). Inner needle behaviour was studied both with and without outer cannula effect. At +4 degrees C to +13 degrees C the needle had a curved course, deviated to the side of its tip. At +4 degrees C, the needle was most deviated (range 4, 8, 10 degrees ) and the samples were largest (8, 12, 12 mm). At -5 degrees C to +1 degrees C the needle was bent, the cannula was not triggered and no sample was obtained. At +16 degrees C and +19 degrees C the needle had a straight course and the length of the sample was decreasing. Behaviour of the inner needle as well as the cannula depends on the hardness of the target. Targets of intermediate hardness yield adequate samples when the inner needle takes a curved course deviated toward the tip and get restored by the cannula.

Behaviour of the 2.1-mm (14 G) automated biopsy needle in phantoms.

To study the behaviour of the 2.1-mm (14 G) core biopsy needle in targets of different consistencies and to correlate the needle behaviour to lengths of the samples. A series of butter blocks at temperatures of -5 degrees C, -2 degrees C, +1 degrees C, +4 degrees C, +7 degrees C, +10 degrees C, +13 degrees C, +16 degrees C and +19 degrees C simulating lesions of different hardness in human breast, were passed with needles (3 passes at each temperature). Inner needle behaviour was studied both with and without outer cannula effect. At +4 degrees C to +13 degrees C the needle had a curved course, deviated to the side of its tip. At +4 degrees C, the needle was most deviated (range 4, 8, 10 degrees ) and the samples were largest (8, 12, 12 mm). At -5 degrees C to +1 degrees C the needle was bent, the cannula was not triggered and no sample was obtained. At +16 degrees C and +19 degrees C the needle had a straight course and the length of the sample was decreasing. Behaviour of the inner needle as well as the cannula depends on the hardness of the target. Targets of intermediate hardness yield adequate samples when the inner needle takes a curved course deviated toward the tip and get restored by the cannula.

MR-guided core biopsies using a closed 1.0 T imager. First clinical results

Objective: High soft-tissue contrast and multiplanar imaging capabilities of MRI may be advantageous in biopsy guidance compared to CT. We report our first results with MR-guided core biopsies using a closed 1.0 T MR imager. Methods and patients: In ten patients, seven liver lesions and one lesion each in the muscle of the back, the gluteal muscle and in the breast were biopsied under MR guidance using MR-compatible needles (Tru-Cut type, 18G and 14G). For control scans T1-weighted turbo-spin-echo (TSE), gradient-echo and T2-weighted TSE sequences were used. Results: In all patients, the suspicious lesions and the biopsy needle were exactly delineated in MR control scans. In nine out of ten patients, the suspicious lesion was clarified histologically. Controls of needle position in a second plane were performed twice. Pushing the inner stylet alone resulted in a distortion of the needle in several cases in its flat area. The small diameter of the MR gantry was inconvenient for a few patients. One complication (intrahepatic bleeding) was observed, which healed up without consequences. Conclusion: Using a closed 1.0 T MR imager MR-guided core biopsies can be conducted efficiently. Core biopsies should be taken by pulling and pushing the outer cannula. Advantageous compared to CT are the multiplanar imaging capabilities, while the smaller gantry is disadvantageous.

Biopsy of Mediastinal Tumors: Needle Biopsy versus Mediastinoscopy

Biopsy of Mediastinal Tumors: Needle Biopsy versus Mediastinoscopy

Hemostatic effect of glue-lipiodol mixture plugged in the needle tract after renal biopsies in a high-risk, anticoagulated rabbit model.

To investigate the hemostatic effect of a glue-lipiodol mixture plugged immediately into the needle tract after renal biopsy of high-risk, anticoagulated rabbits by use of a large-core gun biopsy needle and the subsequent pathological changes of the biopsy tract. Twenty-five rabbits weighing 2 kg were divided into five groups (five rabbits each) according to time of sacrifice at 0, 2, 4, 6, and 8 days after biopsy. After anesthesia was induced, both kidneys were exposed and a bolus of 100 U/kg heparin was administered intravenously. Blood sampling was done twice, once before and once after heparinization, and activated partial thromboplastin times were measured for each. Then renal biopsies were performed in 25 pairs of kidneys by using an 18-gauge automated biopsy gun. The glue-lipiodol mixture was not injected into the first biopsy sites (control). Immediately after the second biopsies were done, 0.5 mL of the glue-lipiodol mixture at a 1:3 ratio was plugged into the needle tract through the outer cannula while withdrawing it slowly. Bleeding times of the two biopsies of each pair of kidneys were measured. All rabbits were humanely killed at their previously scheduled times, and histopathological findings were evaluated for the presence of inflammation, necrosis, foreign body reaction, and fibrosis around the biopsy tract. All parameters were classified into four categories according to the degree of severity, from 0 to + + +. Twenty-five cases (100%) of the controls bled after the biopsies were performed. Four of them (16%) showed immediate, massive, pulsatile bleeding. In contrast, only 11 of 25 cases (44%) bled at the second biopsy (plugged) sites and only two of them (8%) showed pulsatile bleeding. Mean bleeding times were 228 seconds in controls and 26 seconds in the glue-lipiodol mixture-plugged sites (P < 0.000). Histopathological examination of the needle tract in the plugged group revealed mild inflammation in the 0- to 2-day groups and moderate inflammation and mild necrosis in the 4- and 6-day groups. In the 8-day group, inflammation was diminished and only mild fibrosis was noted. There was no foreign body reaction in any of the specimens of the plugged group. We conclude that a glue-lipiodol mixture, when used as a plug material for the renal biopsy tract, is an efficacious method of bleeding control that is associated with a low incidence of pathological alterations in an anticoagulated rabbit model, thus demonstrating its future potential for clinical application.