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Biomedical subjects

G C Hunter

Publications and source records attributed to G C Hunter.

At least 55 records · Page 3Linked to original sources

Shoelace technique for delayed primary closure of fasciotomies.

Performing a timely fasciotomy for compartment syndrome prevents ischemic injury to muscles and nerves. Fasciotomy entails incision of the overlying skin and investing fascia of the compartment, relieving pressure and enhancing tissue perfusion. Delayed primary closure is ideal, but because of skin edge retraction, the open wound must either heal secondarily or be closed with a split-thickness skin graft. The shoelace technique involves running a silastic vessel loop through skin staples placed at the skin edge along the initial fasciotomy incision. Daily tightening of the shoelace permits gradual reapproximation of the skin edges while compartment edema resolves. Closure using a simple suture or Steri-strip (3M Surgical Products, St. Paul, Minnesota) is then possible after 5 to 10 days. The shoelace technique allows for gradual primary closure of open fasciotomy wounds, thereby avoiding the morbidity and cost associated with skin graft or secondary closure.

Compartment Syndromes↗

Popliteal vascular compression in a normal population.

PURPOSE: Positional popliteal artery obstruction is believed to be an important factor contributing to popliteal artery entrapment syndromes. This study was undertaken to define the positional anatomy and physiologic condition of the vessels in the popliteal fossa in groups of highly trained and normally active young men and women. We postulate that at least some symptom-free individuals can occlude the popliteal artery with leg positioning. METHODS: Seventy-two limbs were evaluated in 36 subjects. Symptom-free subjects were recruited in four groups: normally active men, normally active women, male competitive runners, and female competitive runners. All subjects underwent noninvasive testing that included resting segmental limb pressures and Doppler waveforms and color-flow duplex imaging with the leg in the neutral position and then with knee extension with active and passive dorsiflexion and plantar flexion of the foot. Subjects unable to occlude the popliteal artery with positioning were then exercised, and studies were repeated. Magnetic resonance imaging, with magnetic resonance angiography, was conducted on 14 subjects, with each leg studied in the neutral position and with active positioning. RESULTS: Positional popliteal arterial occlusion occurred in 38 of 72 limbs (53%). No intergroup comparisons were statistically significant. The response of each leg was symmetric in 89% of subjects. No subject who could not occlude the popliteal artery at rest was able to do so with exercise. Magnetic resonance imaging disclosed normal anatomy in all subjects and showed the location of popliteal occlusion to be at the level of the soleal sling, with positional compression by the soleus muscle, the lateral head of the gastrocnemius, the plantaris, and popliteus muscles. CONCLUSION: Popliteal arterial occlusion can be induced in 53% of subjects with simple leg positioning caused by myofascial compression. This must be considered when evaluating patients for intervention on the basis of physiologic testing of the popliteal vessels.

Adult↗

Critical carotid artery stenosis: diagnosis, timing of surgery, and outcome.

PURPOSE: Patients with critical carotid artery stenoses have been considered to be at high risk for carotid artery occlusion necessitating urgent or emergency endarterectomy once the stenosis is identified. Included in this group of patients are those with carotid string sign or atheromatous pseudoocclusion (APO). This review was conducted to determine the impact of the severity of stenosis including APO on the treatment and outcome of patients undergoing carotid endarterectomy. METHODS: The records of 203 consecutive carotid endarterectomies performed in 197 patients were reviewed in detail. Patients were stratified into a critical stenosis group (80% to 99% diameter) and noncritical stenosis group based on noninvasive vascular laboratory and carotid arteriography results. Comparisons were performed of demographic data, atherosclerotic risk factors, carotid artery disease presentation, interval between arteriography and endarterectomy, operative details, and surgical results between the critical and noncritical groups and between patients in the critical group with and without APO. RESULTS: Carotid endarterectomies were performed on 91 critical carotid artery stenoses and 112 noncritical stenoses. The groups did not differ significantly with regards to demographics, risk factors, carotid artery disease presentation, mean back pressure, and operative use of shunt or patch closure. For the critical group the interval between arteriography and endarterectomy was 8.63 +/- 2.38 days compared with 9.64 +/- 2.14 days for the noncritical group (mean +/- SEM, p = 0.75). No patient in either group progressed to occlusion in the interval between arteriography and endarterectomy. Perioperative strokes occurred in two patients (2%) in the critical group and four patients (3.6%) in the noncritical group (p = 0.09). Likewise, no significant difference was demonstrated in these variables when comparing patients with critical carotid artery stenosis and APO with those without APO. CONCLUSIONS: The presence of a critical carotid artery stenosis including APO did not impact on the treatment or outcome of patients requiring endarterectomy nor did it imply the need for emergency intervention to prevent thrombosis. Surgical intervention can proceed after evaluation and optimization of comorbid conditions without undue concern for interval thrombosis.

Carotid Artery, Internal↗

Stereotactic fine-needle aspiration cytology of nonpalpable breast lesions: an analysis of 258 consecutive aspirates.

BACKGROUND: The role of stereotactic fine-needle aspiration cytology (SFNAC) in the diagnosis of nonpalpable breast lesions is poorly defined. PATIENTS AND METHODS: Data were prospectively collected from 225 consecutive patients with nonpalpable breast lesions who had aspiration cytology followed by immediate surgical excision. RESULTS: Between 1988 and 1993, 258 such procedures were performed. The results of 84 (33%) were interpreted as benign, 84 (33%) as atypical, 28 (11%) as suspicious for malignancy, and 49 (19%) as malignant. In all, 88 (34%) surgical specimens were malignant. SFNAC had an 80% sensitivity, a 96% specificity, a 91% positive predictive value, and an 89% negative predictive value. There were 18 false-negative and 7 false-positive aspirates. CONCLUSIONS: SFNAC for diagnosing nonpalpable breast lesions is moderately sensitive and highly specific, and has a high positive and negative predictive value. In conjunction with mammography and clinical assessment, the procedure is useful for determining which patients with nonpalpable breast lesions may require surgical biopsy.

Adult↗

Aortic graft infection due to Pasteurella haemolytica and group C beta-hemolytic streptococcus.

Although infection is a rare complication of aortic bypass grafting, we treated a 50-year-old patient who developed aortic graft infection due to Pasteurella haemolytica and group C beta-hemolytic streptococcus. The source of the infection could not be verified; however, after removal of the infected graft and administration of a 6-week course of intravenous ampicillin, he recovered fully. We discuss the etiology and pathogenesis of this rare infection.

Aorta↗

Catheter-directed urokinase thrombolysis: an adjunct to PTA/surgery for management of lower extremity thromboembolic disease.

Catheter-directed thrombolysis was used either alone or as an adjunct to percutaneous transluminal angioplasty (PTA) or surgery for peripheral vascular occlusion on 112 occasions in 102 patients. Symptom duration ranged from < one to > twenty-eight days. Thrombolytic therapy using urokinase plasminogen activator thrombolysis (uPAT), including intrathrombic injection when possible, was successful (> 50% lysis) in 99 procedures (88%). Technical failure (< 50% lysis) occurred in 13 procedures (12%). In 9 of the 13 failures, intrathrombic injection of urokinase was not possible, but the duration of occlusion was > twenty-eight days in all but 1. Two other failures were from embolic sources and 2 more occurred in patients with a hypercoagulable state. The uPAT was adjunctive to PTA/surgery in 56 cases (50%). PTA following uPAT was required and successfully performed in 24 of 27 cases (88.9%). Surgery followed lytic therapy in another 32 (including the 3 failed PTAs). In the remaining 56 cases (50%), no additional intervention was required. There were 20 complications (18%), minor in 16 of 20 (80%). Minor complications included small puncture site hematomas and distal embolization resolved by continued lytic therapy. Four major complications occurred. One was retroperitoneal hemorrhage directly contributing to the only death in the series. The other 3 were hematuria (2) and femoral neuropathy (1). The authors conclude that catheter-directed lytic therapy alone or as an adjunct to PTA/surgery is a valuable approach to peripheral vascular thromboembolic disease. It is less likely to succeed in chronic occlusion. The incidence of complications is moderate but acceptable.

Aged↗

Contraindications and complications of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy is a commonly performed procedure for the removal of symptomatic gallstones. Compared with open cholecystectomy, laparoscopic cholecystectomy is associated with less postoperative pain, earlier discharge from the hospital and a more rapid recovery. However, there are specific contraindications to the procedure, including empyema of the gallbladder, gangrenous cholecystitis, coagulopathy, portal hypertension and peritonitis. Complications from laparoscopic cholecystectomy include common duct injury, bleeding, bile leakage and wound infection. An understanding of these issues allows the family physician to more appropriately select patients for laparoscopic removal of the gallbladder.

Cholecystectomy, Laparoscopic↗

Putative vascular endothelial cell chemotactic factors: comparison in a standardized migration assay.

While a number of chemoattractants of vascular endothelial cells have now been identified in vitro, differences in methodology preclude comparisons of substances evaluated in different assays. Here, we report a standardized chemotactic assay in which the migration of calf pulmonary artery endothelial cells in a 48-well microchemotaxis chamber was determined. Nonstimulated (control) migration was remarkably constant (mean +/- SD, 96 +/- 14) from plate to plate, thus allowing the indexing of relative migration of stimulated cells to that of nonstimulated cells in the control wells of that plate. Based on the relative migrations observed in response to each of the substances evaluated, those proving to be stimulatory of migration were placed in rank order by potency. The growth factors epidermal growth factor, transforming growth factor-alpha, and basic fibroblast growth factor (followed by pentosan polysulfate, plasmin, fibronectin, fibrinogen, granulocyte-macrophage colony stimulating factor heparin, adenosine, and MgSO4) were the most potent. Only the platelet factors platelet-derived growth factor-BB and platelet activating factor proved inhibitory of migration. Combining fibrinogen with other chemoattractants produced either stimulation or inhibition in comparison to the migration observed with fibrinogen alone, suggesting that more than one signal transduction mechanism was, in all likelihood, invoked by the various agents. This assay will allow the rapid screening and rank ordering of additional putative chemoattractants, will facilitate the study of the biochemical mechanisms involved in endothelial cell migration, and will permit the evaluation of pharmacologic agents capable of modulating stimulated or unstimulated migration.

Adenosine↗

Impact of adjunctive testing on the diagnosis and clinical course of patients with acute appendicitis.

The diagnosis of acute appendicitis is usually made from the history and physical examination. Recently, abdominal ultrasonography (US), laparoscopy, computerized tomography (CT), and barium enema (BE) have been used in the preoperative evaluation of patients with presumed appendicitis in order to improve the diagnostic accuracy. However, the usefulness of these tests in verifying the diagnosis of appendicitis has not been established. We reviewed the medical records of 203 patients who underwent appendectomy. One hundred patients were surgically treated before 1984 (group I) and 103 patients underwent surgery after 1988 (group II). Patients in group II were more likely to have preoperative US, laparoscopy, CT, or BE (24 in group II versus 3 in group I, p < 0.05). When groups I and II were compared, the rates of perforation (27% versus 20%), normal appendectomy (8% versus 11%), and the interval between admission and operation (12.2 hours versus 10.7 hours) and length of hospitalization (5.0 days versus 5.1 days) were not significantly different. We concluded that although adjunctive testing may be beneficial in selected patients, its routine use in patients suspected of having appendicitis cannot be advocated at present.

Acute Disease↗

Clinical utilization and complications of sural nerve biopsy.

Surgeons frequently perform sural nerve biopsy as part of the work-up of patients with peripheral neuropathy. The indications for the procedure, therapeutic value, and complications associated with the procedure have received little attention in the surgical literature. A retrospective chart review of 60 patients with the suspected diagnosis of peripheral neuropathy undergoing sural nerve biopsy was performed. Vasculitis was suspected in 29 (48%) patients undergoing biopsy. This diagnosis was confirmed in 6 of the 29 patients and resulted in the alteration of therapy in 31% of patients with this suspected diagnosis. In 27 (45%) patients, the etiology of their peripheral neuropathy was unknown. Twelve (44%) patients in this group had sural nerve pathology; however, no change in therapy was required. Ten patients in our series had associated malignant tumors; some of these patients were diagnosed after referral for sural nerve biopsy. Twenty-five (42%) patients remained undiagnosed after biopsy. Nerve conduction studies were performed in 14 (22%) patients. Thirteen patients with abnormal lower extremity nerve conduction studies had 6 normal and 7 abnormal biopsy results. The one patient with a normal study had a normal nerve biopsy result. There were six (10%) patients with wound infections, seven (12%) patients with delayed wound healing, and three (5%) patients with new onset of chronic pain in the distribution of the sural nerve, for an overall complication rate of 27%. There was no correlation between the preoperative use of antibiotics, type of local anesthetic used, or length of nerve excised and complication rate. We conclude that the complication rate after sural nerve biopsy is significant. Strict criteria should be employed in selecting patients for sural nerve biopsy including a careful neurologic history and physical examination, nerve conduction studies, appropriate work-up for vasculitis if suspected, and implementation of a search for malignancy if this is not apparent. If the diagnosis is still in question, then sural nerve biopsy would seem appropriate, especially in patients with suspected vasculitis.

Adult↗

Management of chyloperitoneum after abdominal aortic surgery.

Chyloperitoneum is a rarely reported complication of abdominal aortic surgery. From 1981 to 1992, we treated 5 cases of chylous ascites after operations on the abdominal aorta and reviewed 22 previously published cases. There were 22 men and 5 women, with a mean age of 63.8 years (range: 27 to 93 years). Twenty cases (74.7%) occurred after abdominal aortic aneurysm resection, 5 (18.5%) after aorto-femoral bypass for occlusive disease, and 2 (6.8%) after resection of infected aortic grafts, 1 for occlusive disease and the other for infrarenal aortic aneurysm. Abdominal distention was the most common presenting symptom, occurring in 26 (96.3%) of 27 patients. The mean time from aortic operation to the development of symptoms was 18.5 days (range: 7 to 120 days). Diagnosis was confirmed by paracentesis, which yielded lipemic, sterile fluid in all patients. Therapeutic paracentesis was not successful when used alone, but, when combined with a medium-chain triglyceride (MCT) diet or total parenteral nutrition (TPN), it resulted in resolution of chyloperitoneum in 8 of 14 patients (57.2%). TPN alone or with paracenteses and/or diuretics was successful in 9 of 15 (60%) patients. Peritoneovenous shunts resolved chylous ascites in four of five patients not responding to diet and/or TPN but resulted in one death due to sepsis. Operative ligation of the injured lymphatic channel was successful in all five patients treated by laparotomy when nonoperative efforts failed. Chyloperitoneum resolved in all but two (7.7%) patients. There were five (18.5%) deaths, but only three (11.5%) were directly related to chylous ascites. Treatment with TPN resolved chyloperitoneum in all five of our own patients. We reached the following conclusions: (1) Chyloperitoneum is a rare complication of aortic surgery; (2) This disorder should be considered whenever persistent abdominal distention appears after aortic surgery; (3) The diagnosis is easily confirmed by paracentesis; and (4) Surgery to close the lymph fistula should be reserved for those patients in whom conservative therapy with MCT diets or TPN has failed.

Adult↗

Hepatic ischemia, caused by celiac axis compression, complicating pancreaticoduodenectomy.

OBJECTIVE: In the course of pancreaticoduodenectomy, profound hepatic ischemia developed in two patients (one with ampullary carcinoma, the other with chronic pancreatitis). This article addresses the diagnosis and correction of the celiac axis compression responsible in this complication. SUMMARY BACKGROUND DATA: Since hepatic ischemia appeared immediately after division of the gastroduodenal--pancreaticoduodenal arcade, which provides mesenteric to celiac collateral circulation, celiac axis narrowing or occlusion was suspected. Previous reports have indicated that celiac axis disease may be present in about 10% of such patients. METHODS: Doppler flow studies, and in the second patient, intraoperative angiography were performed. The celiac axis was exposed and mobilized in both. RESULTS: Initially, no flow could be detected in the celiac axis. Dense fibrous tissue was found encasing it. Division of the entrapping tissue restored flow to the upper abdominal viscera. CONCLUSIONS: The anatomic deformation of the celiac axis predisposing to this complication is detectable on the lateral projection of a preoperative celiac angiogram. If, however, an angiogram has not been done, an initial test occlusion of the gastroduodenal artery before its division permits anticipation of the complication, correction of the celiac impingement, and hence, avoidance of hepatic ischemia.

Aged↗

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

Stroke is a significant cause of morbidity and mortality following coronary artery bypass grafting (CABG). Over a 30-month period, 245 consecutive patients undergoing elective CABG were prospectively examined to determine which risk factors might predispose to stroke following surgery. The risk factors evaluated included hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, smoking, atrial fibrillation, a history of cerebrovascular accident or transient ischemic attack, carotid artery stenosis > 60% documented by duplex scanning, severe atherosclerosis of the ascending aorta, and the presence of ventricular thrombus. Postoperative stroke occurred in five of the 245 patients (2%), four evident immediately on awakening and one on day 7 after surgery. The probable causes of the immediate strokes were atheroembolism in three patients and severe ipsilateral carotid stenosis in one. Hypertensive hemorrhage was responsible for the one case of delayed stroke. In this study, carotid artery stenosis did not presage stroke following CABG, but ventricular thrombus was highly predictive of stroke after surgery.

Aged↗

Contrast-induced nephrotoxicity: the effects of vasodilator therapy.

The increasingly frequent use of contrast-enhanced imaging for diagnosis or intervention in patients with peripheral vascular disease has generated concern about the incidence and avoidance of contrast-induced nephrotoxicity (CIN). In this prospective study, we sought to identify those patients at greater risk of developing CIN and to evaluate the efficacy of vasodilator therapy with dopamine in limiting this complication. Baseline serum creatinine (Cr) concentrations were obtained on admission and daily for up to 72 hr after angiography in 222 patients undergoing 232 angiographic procedures. The preangiographic treatment was varied at 2-month intervals for 1 year. All patients received an intravenous infusion of 5% dextrose and 0.45% normal saline at a rate of 75 to 125 ml/hr. During the first interval patients received 12.5 g of 25% mannitol immediately prior to their contrast load, in addition to intravenous fluids. During the next 2-month period the patients were given renal dose dopamine intravenously (3 micrograms/kg/min) commencing the evening before angiography and continued to the next morning. During the latter half of the study the treatment regimens were modified so that the use of mannitol was restricted to patients with diabetes mellitus and dopamine to patients with serum creatinine concentrations of > or = 2 mg/dl. Postangiographic elevation in Cr occurred in 2, 10.4, and 62% of studies in patients with baseline creatinine levels of < or = 1.2 mg/dl, 1.3 to 1.9 mg/dl, and > or = 2.0 mg/dl, respectively. None of the patients receiving dopamine experienced an elevation in creatinine. There was no statistical correlation between age, diabetes, or medication with calcium channel blockers and CIN.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Improved sterile technique diminishes the incidence of positive line cultures in cardiovascular patients.

In order to determine the incidence of positive line cultures, especially as affected by differing protocols for line insertion, cultures were obtained from lines in residence for up to 4 days from cardiac patients (who received Cefuroxime) and vascular patients (who received Cefazolin) as prophylaxis perioperatively. Positive cultures were obtained from 95 (19%) of 496 lines in cardiac patients and 83 (31%) of 261 lines in vascular patients. There was a linear relationship between duration of line residence and the incidence of positive line cultures, increasing from 14% on Day 1 to 33% on Day 4. The use of full sterile technique at the time of insertion halved the incidence of subsequent positive line cultures. Four of the 403 (1%) patients each had a single episode of postoperative line sepsis. Another four patients developed wound infections with the same organisms as cultured from their lines. One patient has had a vascular graft infection with the same organism cultured as was isolated from a Swan-Ganz line 1 year previously. These data suggest that monitoring lines should be inserted using full sterile technique and removed as soon as the patient is hemodynamically stable.

Cardiac Surgical Procedures↗

Effect of surgical manipulation of polytetrafluoroethylene grafts on microstructural properties and healing characteristics.

The effects on graft healing of alterations in the microstructure of polytetrafluoroethylene (PTFE) grafts induced by surgical instruments have not been fully elucidated. This study evaluates changes in the structural and physical properties of PTFE grafts resulting from the intentional application of commonly used surgical instruments and the influence of these changes on cellular ingrowth. The extent of cellular ingrowth into intact (10, 30, and 60 microns unreinforced and 30 microns reinforced [R]) and structurally compromised PTFE grafts (30 reinforced and 60 microns nonreinforced) implanted subcutaneously in Sprague-Dawley (n = 14) rats was evaluated at 7 and 21 days. The thrombogenicity of 10-, 30-, 60-, and 80-microns intact graft segments was determined gravimetrically after suspension in the internal jugular vein of dogs for 90 minutes. Cellular ingrowth consisting of fibroblasts, macrophages, and microvessels was directly related to porosity and was most extensive in 60-microns uncompromised graft segments, being 7-, 17-, and 20-fold greater than was observed in 60- and 30R-microns compromised grafts and undamaged 10-microns grafts, respectively. There was a direct relationship between porosity and thrombogenicity of intact graft segments suspended in the jugular vein. The amount of thrombus adherent to 80-microns graft segments was eightfold greater compared with 10-microns grafts. Manipulation of PTFE with surgical instruments significantly impairs healing and may be a possible etiologic factor in the poor long-term performance of these grafts.

Animals↗