Accurate deployment of vena cava filters: comparison of intravascular ultrasound and contrast venography.

BACKGROUND: The increasing use of vena cava filters by trauma surgeons has led to reports of filter placement using intravascular ultrasound (IVUS). Although attractive because of its ease of use and elimination of contrast and radiation, no studies have examined the accuracy of filter placement by IVUS as compared with contrast venography (CV). The purpose of this study was to compare the anatomic information obtained by both techniques during filter placement. METHODS: Twenty-one patients meeting trauma service criteria for filter placement were studied (11 women and 10 men; mean age, 46.8 years). All procedures were performed in the operating room by trauma surgeons. Vascular access was obtained by percutaneous placement of an 8 French sheath in the right femoral vein. CV, IVUS, and bilateral selective renal venography were performed before deployment of a Greenfield filter. Localization and diameter measurements were made in reference to a radiopaque ruler placed on the patient's abdomen. We chose the "best location" for filter deployment as 1 cm below the junction of the lowest renal vein and the vena cava. Measurements by CV and IVUS were compared with the "gold standard" of selective renal venography. RESULTS: As compared with selective renal venography, the difference between best location by CV and IVUS was 16.3 +/- 13.8 mm and 3.7 +/- 5.6 mm, respectively (p = 0.001). In four cases (19%) the CV missed best location by 3 cm or more. CV overestimated the diameter of the vena cava in all cases. Average vena cava diameter was 26.4 +/- 3.3 mm by venography and 20.6 +/- 3.1 mm by IVUS (p < 0.0001). CV incorrectly identified four patients as having vena cava diameters too large (>2.8 cm) for the placement of a Greenfield filter. The two renal vein anomalies (one double left renal vein and one absent left renal vein) were correctly diagnosed by IVUS. CONCLUSION: IVUS is a more accurate method of localizing the renal veins and measuring vena cava diameter for placement of vena cava filters than contrast venography.

Tuberculous enteritis: a case report.

Tuberculous enteritis is an unusual diagnosis in the United States. Because this entity is rare and the symptoms are not specific, the physician must have a high index of suspicion. We report the case of a young man with tuberculous involvement of the gastrointestinal tract who required surgical intervention for small bowel obstruction.

Schwannoma of the cervical sympathetic chain: it's not a carotid body tumor.

Schwannoma of the cervical sympathetic chain is a rare nerve tumor with fewer than 40 confirmed cases in the English literature. These lesions typically present as an asymptomatic neck mass and are easily mistaken for a carotid body tumor during the initial workup. We report a case of schwannoma of the cervical sympathetic chain in a 35-year-old man followed by a review of the current literature.

Improved antibody responses to delayed pneumococcal vaccination in splenectomized rats.

Pneumococcal vaccination following splenectomy is widely used as prophylaxis against overwhelming postsplenectomy infection. There remains controversy however, over the timing of vaccination. We hypothesized that delaying vaccination would increase the antibody response. Pneumococcal vaccinations were given at designated intervals to rats that had undergone either a sham abdominal surgery or splenectomy. Sixty male Sprague-Dawley rats, 250 to 400 g, were divided into three groups for vaccination: I, 1 day postoperatively; II, 7 days postoperatively; and III, 28 days postsplenectomy/sham. Serum antibody levels were then determined by enzyme-linked immunosorbent assay at 5 and 21 days after vaccination. Immunoglobulin (Ig) levels after delayed vaccination at 1 week postoperatively and 1 month postoperatively were significantly higher than levels from rats vaccinated 1 day postoperatively. IgM levels after vaccinations 1 week and 1 month postoperatively were also significantly higher than levels of rats vaccinated 1 day postoperatively (P < 0.05 for both IgG and IgM). On the basis of these results, we conclude that delaying vaccination after splenectomy enhances antibody responses.

Surgical clerkship performance of traditional and nontraditional students in a problem-based learning environment.

BACKGROUND: To determine whether nontraditional students perform better than traditional students during surgical clerkships as reflected on the surgical clerkship final examination. METHODS: Retrospective review of medical student records from the classes of 1986 through 1993. Students admitted soon after completing undergraduate training were identified as "traditional," and those having prior careers as "nontraditional." RESULTS: There were 150 traditional and 72 nontraditional students. The ratio of men to women and admission MCAT scores were not significantly different. Traditional students were significantly younger and had higher admission grade point averages (GPAs). Nontraditional students were more likely to be married and have children. Final examination scores of traditional and nontraditional students were not significantly different. MCAT scores and college GPAs were the best predictors of final examination performance. Married students performed significantly better than single students. CONCLUSIONS: There was no significant difference between nontraditional and traditional student performance on the surgical clerkship final examination.

A technique for the creation of long autogenous tissue arterial patches.

An endarterectomized segment of an occluded artery (e.g. superficial femoral artery), is an alternative autogenous material for patch angioplasty which preserves the continuity of the saphenous vein. A technique of incising endarterectomized segments of superficial femoral artery in a spiraled manner is presented which allows for the creation of long autogenous tissue patches. A spiral is drawn on the exterior of a harvested arterial segment which is either 1 cm, 7 mm or 5 mm in width. When incised along the spiral, the length of the resulting elliptical patch will be two, three, or four times, respectively, the length of the original artery segment. The authors have used the technique to close extended profundoplasty in three patients and for construction of a patched distal anastomosis in two patients undergoing prosthetic femoropopliteal bypass grafting. There have been no early complications.

Mesenteric lymphangioma causing bowel obstruction in a child.

Mesenteric lymphangioma was manifested as a bowel obstruction in a child with cerebral palsy. Diagnosis was not confirmed until the time of laparotomy. Mesenteric lymphangioma is rare but should be considered in a child with bowel obstruction and no other known abdominal disease.

Surgery in nonagenarians: morbidity, mortality, and functional outcome.

BACKGROUND: There are few studies that document the outcomes experienced by very old patients who undergo major surgery. METHODS: This is a case series and 7-year follow-up of 116 consecutive patients who were aged 90 years or older and underwent major surgery at a large university-affiliated community hospital. We describe the functional status, short- and long-term mortality, and predictors of mortality in this group of frail elders. RESULTS: The 116 nonagenarians in this study underwent 134 major operations. Sixty-three patients were admitted to the hospital from a nursing home. The most common surgical procedures were for hip fracture, lower extremity amputation, and abdominal problems. Nineteen patients died in the hospital following surgery, and 23 patients died within 30 days of operation. Follow-up at 7 years revealed that all but three patients had died. Survival was worse for patients admitted from nursing homes, those who were nonambulatory before surgery, and those with major or complete functional impairment. CONCLUSIONS: Major surgery in nonagenarians is associated with a 20% perioperative mortality. Functional status and ambulatory ability are maintained in most patients. Whether to operate on these frail elders is a complex decision.

Isolated symptomatic midcervical stenosis of the internal carotid artery.

All carotid arteriograms performed between January 1, 1986 and December 31, 1991 were reviewed for instances of midcervical carotid stenosis. Sixteen cases were identified. A stenosis related to the hypoglossal nerve was specifically identified in three operative reports in the retrospective review. Pathologic examinations of the specimens confirmed the presence of atherosclerotic plaque or fibrous dysplasia. In another case, relief of intermittent neurologic symptoms (TIAs) was obtained by division of the stylohyoid ligament. Prospective observation of five cases confirmed a stenosis immediately distal to a transverse neurofascial band formed by the hypoglossal nerve, which arose with the vagus nerve in three patients, and a large cervical contribution to the ansa hypoglossi in two. Presumably the lesion was caused by the turbulent flow in the internal carotid artery distal to the band. Isolated stenosis of the midcervical internal carotid artery unrelated to bifurcation disease may be the result of turbulence induced by tethering neural or myofascial bands.

Results of venous thrombectomy in the treatment of deep vein thrombosis.

Despite the infrequent use in the United States, venous thrombectomy seems to have a beneficial effect in carefully selected patients with acute iliofemoral thrombosis. The final decision to proceed with venous thrombectomy should be based on a balanced analysis of two factors--the characteristics of the thrombus and the characteristics of the patient. First, the diagnosis of acute deep vein thrombosis must be unequivocally established preoperatively. Accurate anatomic localization is usually achieved with venography, but duplex Doppler examination may be sufficient in selected instances. Second, the distribution of thromboses should be determined. Venous thrombectomy should be considered only in instances of deep vein thrombosis involving the iliofemoral venous segment. Thrombectomy for venous thrombosis below the inguinal ligament has not been consistently beneficial. Third, the age of the thrombus should be estimated. This can usually be accomplished though a careful analysis of the clinical history, but may be corroborated by duplex Doppler or venographic features of the thrombus. Venous thrombectomy should rarely be attempted if the age of the thrombus is thought to be greater than 72 hours. Unfortunately, in many instances the clinical history substantially underestimates the actual age of the underlying thrombus. Fourth, patient characteristics must be assessed preoperatively. While venous thrombectomy can usually be accomplished using local anesthesia, substantial shifts in fluid and acid base balance may be poorly tolerated by elderly, frail patients. In the setting of widespread metastatic disease, rethrombosis rates may be too high to justify thrombectomy in some patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical treatment of superior mesenteric artery dissecting aneurysm and simultaneous celiac artery compression.

Spontaneous dissections of visceral arteries are rare, but when they do occur, they most commonly involve the superior mesenteric artery (SMA). We present a case of intestinal ischemia caused by a spontaneous dissection of the SMA in a patient with simultaneous celiac artery occlusion. The patient was a 45-year-old woman who presented with intestinal angina of sudden onset. Arteriography revealed the classic findings of SMA dissection and occlusion of the celiac artery. The patient underwent repair of both visceral vessels and made a full recovery. The 18 previously reported cases of isolated, spontaneous dissection of the SMA are reviewed. No previous case has been associated with celiac compression syndrome. The reported experience with symptomatic dissections of the SMA would suggest that prompt surgical repair is indicated and yields excellent results.

Thru-knee amputation: the operation of choice for non-ambulatory patients.

Between 1983 and 1990, 32 consecutive patients had 35 thru-knee amputations for ischemia causing infection or gangrene of the lower leg. Twenty-seven patients were nonambulatory, five had limited mobility, and none were considered to be candidates for rehabilitation with a prosthesis after surgery. The average age was 73 years. Thirty-day hospital mortality was 3 per cent. The incidence of complications was low, and healing was achieved in 97 per cent of survivors. One patients required revision to an above-knee amputation. Average postoperative hospital stay was 8.7 days. It is concluded from this study that thru-knee amputation is the treatment of choice in patients with nonsalvageable ischemic legs and in whom ambulation is not planned after operation.

Is anticoagulation indicated for asymptomatic postoperative calf vein thrombosis?

The purpose of this study was to determine the effect of anticoagulation on the incidence of thrombotic propagation and pulmonary embolism in patients with calf vein thrombosis after total hip or total knee arthroplasty. Patients undergoing arthroplasties had prospective surveillance for postoperative deep vein thrombosis by both bilateral contrast venography and venous duplex scanning. Calf vein thrombosis was documented by venography in 42 patients (50 limbs), including 29 of 253 patients undergoing total hip arthroplasty (11.4%) and 13 of 99 patients undergoing total knee arthroplasty (13%). Of patients on whom follow-up duplex scans were performed, heparin followed by warfarin anticoagulation was used in 11 (13 limbs) and withheld in 21 (25 limbs). Propagation of thrombosis to the popliteal or superficial femoral vein or both was detected by serial duplex scanning in 3 of 13 treated limbs (23%) and 2 of 25 untreated limbs (8%), (p = 0.43). All thrombus propagations were detected within 2 weeks of the operative procedure. There were no pulmonary emboli or deaths. Propagation of asymptomatic calf vein thrombosis after arthroplasty was not influenced by anticoagulation, suggesting that postoperative calf vein thrombosis need not be routinely treated. Serial venous duplex scanning is useful to identify the occasional patient in whom thrombotic propagation requiring anticoagulation develops.

Intravenous recombinant soluble human thrombomodulin prevents venous thrombosis in a rat model.

Thrombomodulin is an endothelial surface thrombin receptor. Thrombin bound to thrombomodulin loses all procoagulant activity and instead activates the protein C anticoagulant pathway. We developed a recombinant thrombomodulin analog and compared the effects of recombinant thrombomodulin (100 micrograms/ea), saline (controls), recombinant hirudin (1.0 mg/kg), and heparin (100 units/kg) on thrombus formation, activated partial thromboplastin time, and tail transection bleeding time in a rat model of stasis-induced venous thrombosis. Results showed that thrombus was detected in the vena cava in six of the six rats treated with saline solution, in zero of the six rats treated with recombinant thrombomodulin (p less than 0.05), in one of six rats treated with recombinant hirudin (p less than 0.05), and in zero of six rats treated with heparin (p less than 0.05). The activated partial thromboplastin time in rats receiving recombinant thrombomodulin was slightly longer than controls (22 +/- 8 vs 37 +/- 6, p less than 0.05). The bleeding times in rats receiving recombinant thrombomodulin were approximately twice as long as controls (215 +/- 68 vs 545 +/- 173, p = 0.037). In all rats treated with recombinant hirudin or heparin, activated partial thromboplastin times were greater than 120 seconds and bleeding times were greater than 1200 seconds. We conclude that recombinant thrombomodulin inhibits venous thrombosis in a rat model with less prolongation of activated partial thromboplastin time and bleeding time than heparin or hirudin.

Thrombomodulin activity on human saphenous vein grafts prepared for coronary artery bypass.

Thrombomodulin, a membrane glycoprotein present on normal vascular endothelium, binds circulating thrombin and is important in protein C activation. These functions contribute to the nonthrombogenic nature of endothelium. Damage during harvest and ex vivo storage of vein grafts may result in dysfunction of this endothelial anticoagulant barrier and possibly contribute to early graft thrombosis. We studied the functional activity and antigenic expression of thrombomodulin on saphenous veins before (initial) and after (harvested) harvest and storage for coronary artery bypass grafting in 15 patients. Also, fresh saphenous vein was studied after mechanical endothelial stripping. After storage for 2.7 +/- 0.6 hours at room temperature in heparinized saline, thrombomodulin functional activity in harvested vein segments was 28% less than initial segments (p = 0.08). Endothelial stripping resulted in a 79% reduction in thrombomodulin activity compared with initial segments (p = 0.04). Immunohistochemical staining confirmed thrombomodulin antigen on vein grafts after harvest and storage, but not on segments stripped of endothelium. Thrombomodulin functional activity and antigenic expression on human saphenous vein grafts is not significantly changed by harvest and relatively short periods of storage at room temperature in heparinized saline.

Surgical treatment of pleomorphic carcinoma of the pancreas.

Pleomorphic carcinoma of the pancreas is a rare malignancy that carries a poor prognosis. This case describes a patient with a pleomorphic carcinoma of the head of the pancreas, cured by a pylorus sparing pancreaticoduodenectomy. The literature is reviewed with emphasis on the surgical cures reported. The giant cell variety of pleomorphic carcinoma may carry a better prognosis. Pleomorphic histology of pancreatic neoplasms is not a contraindication for surgical resection.