Greenfield filter fixation in large venae cavae

PURPOSE

It is generally thought that the Greenfield filter should not be placed in inferior venae cavae (IVCs) that are larger than 28 mm in diameter because of its base diameter. However, the newer versions have larger base diameters. The purpose of this study was to evaluate fixation of the three currently available Greenfield filters in large IVCs.

MATERIALS AND METHODS

Filter fixation was tested in an ex vivo perfusion system with a 34-mm-diameter equine IVC. Greenfield filters with base diameters of 30 mm (original 24-F version [24-F GF]), 38 mm (percutaneous titanium [TGF]), and 32 mm (percutaneous stainless steel [SGF]) were deployed. Increasing force was then applied in a cephalic direction and the resultant movement was measured.

RESULTS

In a 34-mm-diameter IVC, the TGF and SGF demonstrated significantly less movement than did the 24-F GF (P < .001). None of the TGFs or SGFs moved above the renal veins with a 480-g pull. Three of the seven 24-F GFs moved above the renal veins at 30 g. No significant difference in fixation was demonstrated between the TGF and the SGF (P = .6).

CONCLUSIONS

In a 34-mm-diameter IVC, fixation of the TGF and SGF was significantly better than the 24-F GF. The TGF and SGF may not be subject to the same 28-mm-diameter IVC size limitation as the 24-F GF.

Vena cava filter ensnarement and delayed migration: an unusual series of cases

PURPOSE

To review delayed and guidewire-induced morbidity associated with vena cava filters.

METHODS

The records from the Johns Hopkins Hospital, a tertiary care referral center, of all patients who had vena cava filter complications from August 1993 through July 1996 were retrospectively reviewed.

RESULTS

Five patients had filter migration or ensnarement with a guidewire. One patient had delayed extrusion of a filter strut into the duodenum. Four patients had filters ensnared by guidewires, including one during initial filter placement and one several years after placement.

CONCLUSIONS

Delayed complications of vena cava filters should be considered whenever unusual patient signs or symptoms cannot be easily explained, even in the absence of a history of filter placement. To prevent guidewire ensnarement of filters, simple techniques should modify endovascular procedures when vena cava filters are present.

Recurrence of pseudoaneurysm after successful embolization

PURPOSE

To report the initial successful treatment of a hepatic pseudoaneurysm by a partially formed coil and subsequent recurrence secondary to coil migration and configuration change.

METHODS AND RESULTS

A 22-year-old man suffered a gunshot wound in the abdomen; a grade 4 liver laceration was identified and repaired. Eight days later, abdominal pain developed, and pseudoaneurysms were noted off both the superior and inferior branches of the right hepatic artery. Coil embolization was successful in occluding both defects; however, the inferior branch coil was incompletely formed. Twenty days later, symptom recurrence prompted angiography. The inferior branch coil had changed position and configuration, resulting in a larger pseudoaneurysm. Repeat embolotherapy was successful.

CONCLUSIONS

The possible sequelae to maldeployed occluding coils must be considered even if the procedure appears successful. It may be advisable to place additional coils to more confidently occlude the pseudoaneurysm.

Lack of distant migration after injection of a 125iodine labeled dextranomer based implant into the rabbit bladder

PURPOSE

In recent years endoscopic treatment of stress incontinence and vesicoureteral reflux has been introduced. Reports of possible particle migration of the injected material to distant organs in humans and experimental animals have led to a search for biological nonmigration products. An implant found to have a good clinical effect in these conditions is dextranomer in hyaluronan. We performed this study in rabbits to investigate the possible migration of dextranomer particles.

MATERIALS AND METHODS

125Iodine labeled dextranomer particles were injected into the submucosal space of rabbit bladders, and samples of blood and various tissues were examined for radioactivity at scheduled intervals during a 28-day period. Furthermore, whole body autoradiography was performed 1 day, and 1 and 4 weeks after injection.

RESULTS

Radioactivity was found in blood samples and in all tissues but it remained at the background activity level except in the thyroid, where uptake representing free 125iodine was detected. In the bladder 41 and 45% of the injected dose remained within the bladder wall 1 day and 4 weeks, respectively, after injection. The remainder of the dose probably disappeared from the bladder wall by leakage into the urine shortly after deposition, as indicated by the finding of 10-fold higher urine radioactivity levels at day 1 than at day 28 after injection.

CONCLUSIONS

No distant migration of dextranomer particles occurs after submucosal injection of such an implant in the rabbit bladder wall.

Pearls and perils in the management of prolonged, peculiar, penetrating esophageal foreign bodies in children

BACKGROUND/PURPOSE

Most retained esophageal foreign bodies (FB) are identified soon after ingestion and are easily extracted. A minority of FB ingestions are not identified for weeks to years and present significant problems for retrieval. The purpose of this study was to describe the diagnostic and therapeutic strategies needed to care for children who have chronic esophageal FBs.

METHODS

Five children were identified as having retained esophageal FBs 2 months to 2 years after ingestion. During the same 3-year period, 100 children who had acute FBs were identified and had their foreign bodies removed endoscopically. The average age of the children was 3 years (range, 2.4 to 3.5).

RESULTS

The average age of the five children identified in this study was 3 years. The items ingested included coins, a heart pendant, a clothespin spring, and a toy soldier. Complications from chronically retained foreign bodies were bronchoesophageal fistula, mediastinitis, esophageal diverticulum, and lobar atelectasis. One patient died from an aortoesophageal fistula. In all children, endoscopic removal was attempted. Barium esophagram was then performed, and foreign bodies were eventually removed via right thoracotomy.

CONCLUSIONS

Long-retained esophageal FBs are extremely morbid and life threatening. History most often identifies excess salivation, new onset asthma, and/or recurrent upper respiratory infections. Three diagnostic adjuncts are helpful in identifying the presence of a long retained FB: (1) Chest x-ray (PA and lateral), (2) barium swallow, and (3) esophagoscopy. Indications for thoracotomy for removal of foreign body include (1) Poor endoscopic visualization of FB because of inflammatory tissue and (2) Herald bleeding during endoscopy.

The Tempofilter: a multicenter study of a new temporary caval filter implantable for up to six weeks

A multicenter study was conducted to evaluate a new temporary caval filter (Tempofilter) designed to be implanted for up to 6 weeks. A total of 66 patients with a mean age of 51.8 years were enrolled in the study. All had documented high risk of pulmonary embolism: severe deep venous thrombosis in 89.5% of cases and previous symptomatic pulmonary embolism in 65% of cases. Filter placement was performed in association with a surgical or obstetrical procedure in 68.5% of cases. The indication for filter placement was contraindication to or failure of anticoagulant therapy in 85% of the cases. The mean duration of implantation was 29.9 days. Pulmonary embolism was not observed during the implantation period. Partial thrombosis of the filter was observed in 15% of cases due to trapping of clots by the filter. Thrombosis did not hinder filter removal when attempted. Filter-related complications were minor. Filter migration occurred in only 7.5% of cases. Migration never led to complications and did not hinder filter removal. In all cases migration was due to specific, preventable causes. The results of this study show that the Tempofilter is not only safe and easy to use but also effective in preventing pulmonary embolism. A significantly longer maximum implantation time is a major advantage of the Tempofilter over conventional temporary filters. We believe that this filter can be used for temporary protection against the risk of pulmonary embolism particularly in young patients and in a surgical setting.

Hepatic foreign body in a child

The majority of foreign bodies (FBs) swallowed by children are passed spontaneously without event. Perforation of the intestine with migration to the liver is rare. A child with a needle in the right lobe of the liver is reported.

Extrusion of Teflon aortic pledgets from a sternal wound six years after cardiac surgery

We present a case of a cardiac surgery patient with a persistent low-grade discharge from his sternal wound for over six years. It finally healed when some suture material and Teflon felt pledgets were extruded. These had been used intraoperatively to close the aortic cannulation site. The extrusion of prosthetic material from this site after this length of time has never been described.

Surgical clip as a nidus for a common bile duct stone: radiographic demonstration

Surgical clips can migrate into the biliary tract and act as a nidus for stone formation. We present a case of a surgical clip within a common bile duct stone. This diagnosis was suggested by clip movement on serial abdominal radiographs and metallic density within the common duct stone on computed tomography. Confirmation was made by retrograde cholangiogram.

Migration of silicone through the fibrous capsules of mammary prostheses

The usual reaction of the human body to implantation of a silicone prosthesis is formation of a fibrous capsule. Local reactions to silicone outside this fibrous capsule and distant migration of silicone particles have been described. So far, transcapsular migration of silicone particles from the mammary implant through the fibrous capsule of mammary prostheses has not been studied. In this prospective study 71 capsules found in 40 patients were histologically studied. The chi-squared test was applied to evaluate a possible correlation between silicone migration on the one hand and implant age and integrity of the prostheses on the other. The degree of silicone migration was discerned in four stages. Stage 1 represents no silicone particles in the capsule, stage 2 represents migration up to less than half of the capsule thickness, stage 3 shows migration confined to the outer half of the capsule thickness, and stage 4 means transcapsular silicone migration. In only 4 of 71 capsules no migration into or through the capsule was observed. The degree of silicone migration was significantly less in patients in whom the capsule was calcified and was significantly more in patients in whom implantation exceeded 12 years. There was no significant correlation between the status of the prosthesis (intact, bleeding, or ruptured) and the degree of silicone migration.

Missiles in the cardiovascular system

A missile in the cardiovascular system is a rare complication of a projectile wound. A missile in the heart should be suspected in the patient with a projectile wound of the thorax and in whom, on chest radiography, a missile is seen in the cardiac silhouette. A missile should be suspected in the patient with a projectile wound elsewhere with similar radiographic findings, no exit wound, and no missile in the area of injury. A missile in the arterial system should be suspected when no exit wound and no projectile are seen in the traumatized area. In such a case, radiography of the entire body should be done. The diagnosis of a suspected missile in the cardiovascular system is confirmed by echocardiography or angiography. Treatment should be individualized according to the clinical manifestations of the patient and the site of the missile.

Expandable stents: unusual locations

OBJECTIVES

Expandable metallic prostheses have been used widely for malignant biliary stenoses and are being used increasingly for malignant dysphagia and esophago-airway fistulas. Potentially, such prostheses can be placed for gut neoplasms obstructing beyond the esophagus or gastric cardia. This series reports our experience with expandable metallic stents in the stomach, jejunum, and colon.

METHODS

All patients with expandable gastrointestinal stents (other than biliary tree or esophagus) were reviewed. Indications for stent placement, type and location of prosthesis, patient demographics, procedural problems, and data with regard to outcome were defined.

RESULTS

Over a 6-yr period, expandable prostheses (Z stent, Esophacoil, and Ultraflex) were placed in nine patients with widespread malignancy (afferent loop obstruction, three; colon obstruction, three; gastric outlet obstruction, two; and esophagojejunal interposition stricture, one). There was one colon perforation as a consequence of dilation prior to placement of the prosthesis. Subsequent problems included migration (one), occlusion by food bolus (one), and tumor overgrowths/ingrowths (three) which were treated with laser. Median survival approximated 9 months.

CONCLUSIONS

Expandable metallic prostheses have the potential to palliate malignant gastrointestinal stenoses that have traditionally been treated with surgical bypass or comfort care measures only.

Transvenous closure of secundum atrial septal defects: preliminary results with a new self-expanding nitinol prosthesis in a swine model

BACKGROUND

Our purpose was to evaluate a new prosthesis for percutaneous closure of secundum atrial septal defects (ASDs).

METHODS AND RESULTS

Percutaneous closure of surgically created fossa ovalis ASD was attempted in 15 minipigs. The mean balloon-stretched ASD diameter was 12.3+/-2.3 mm (range, 10 to 16 mm). The self-expanding prosthesis was braided from 0.005-in Nitinol wires in the shape of two flat buttons with a short connecting waist with a diameter corresponding to that of the defect to be closed. Polyester filling was added to enhance thrombogenicity. Pulmonary arteriography with levo-phase was obtained before placement; immediately after placement; and at 1-week, 1-month, and 3-month follow-ups. Four animals were killed at 1 week, 1 month, and 3 months for histopathological correlation. Three deaths resulted from ventricular fibrillation (one during anesthesia and two during the placement procedure). Successful placement of the prosthesis was achieved in the remaining 12 animals. Overall immediate ASD closure on angiography occurred in 7 of 12 animals (all polyester-filled prostheses). Absent or trace shunt by angiography was present in 11 of 12 devices at 1 week, with the remaining one demonstrating a small shunt. All septal defects were completely closed at 1 month with the exception of one case in which delayed partial dislodgment of an undersized prosthesis into the right atrium had developed. Closure rate at 3 months was 100%. Neoendothelialization and fibrous incorporation of the prosthesis were completed within 1 to 3 months.

CONCLUSIONS

Effective and permanent occlusion of secundum ASDs is feasible with a device that offers the advantages of easy placement, self-centering, and repositionability.

The vanishing defibrillator syndrome: incidence, mechanism, and clinical relevance

Intraperitoneal migration of an abdominally implanted cardioverter defibrillator is a complication not yet fully described. In a consecutive series of 195 patients, migration occurred between 1 and 20 months in 5 (8%) of the 63 patients in whom a subrectus abdomini placement of the generator was chosen. It was unrelated to the patients' clinical characteristics or the defibrillator model. Dysuria and inability to interrogate the device were present in every subject, and the diagnosis was confirmed by the characteristic abdominal x-ray appearance and the findings at the time of surgery. Adhesions involving the omentum, and in one case, the small bowels, were present in three patients and seem to be related to the length of intraabdominal permanence of the generator. Because this complication may be due to specific anatomical characteristics of the aponeurosis of the abdominal muscles, it is likely that its incidence will be unchanged by the use of smaller devices. A close follow-up of the generators implanted deep to the rectus fascia is therefore advisable.