Intraoperative bacterial contamination of vascular grafts: a prospective study

The establishment of graft infection depends on host response, an appropriate field and bacterial contamination. Intraoperative bacterial contamination of prosthetic graft material was studied prospectively in 77 patients. Vascular reconstruction was indicated for abdominal aortic aneurysm (15%), claudication (42%), rest pain (25%) and ulceration or gangrene (18%). In 78% of cases the procedure was elective. Staphylococcus epidermidis was isolated in 80% of cultures; mixed flora were more frequent in patients with rest pain (60%) and ulceration or gangrene (45%) than in those with aneurysms (22%) or claudication (16%). Grafts became contaminated in 56% of cases using standard techniques; this was lowered to 35% when the surgeon changed gloves before preclotting the graft. There was no significant difference with respect to the surgeon who performed the operation, the indication for operation, primary versus secondary repair or the use of skin barriers. One patient (1.3%) had an established graft infection. It is concluded that the incidence of contamination is high but may be decreased by glove changing.     

Thrombolytic therapy of synthetic graft occlusions before vascular reconstructive procedures.

The objective of this study was to evaluate the impact of thrombolysis of synthetic grafts before urgent vascular reconstruction. In 29 patients, 41 thrombosed synthetic grafts that underwent intraarterial thrombolysis were studied. The cases were divided into three groups: group I--complete thrombolysis followed by reconstruction; group II--complete thrombolysis alone; and group III--incomplete lysis requiring reconstruction or sympathectomy. Follow-up ranged from 1 to 556 days (mean: 149 days). Kaplan-Meier analysis was used to determine patency and limb salvage rates. One-year patency and limb salvage rates were 53% and 95%, 34% and 67%, and 38% and 48%, respectively, for groups I, II, and III. Eighteen complications occurred in 16 of the 41 (39%) episodes. One patient died of intracranial hemorrhage. The best results were achieved when complete lysis was followed by appropriate reconstruction. Patency was equally poor in complete thrombolysis alone and reconstructions required by incomplete thrombolysis. Limb salvage was better after complete thrombolysis, regardless of the appropriate reconstruction.     

Cage versus tricortical graft for cervical interbody fusion. A prospective randomised study

We conducted a prospective, randomised study of 42 cervical interbody fusions undertaken with either an autologous tricortical graft or a cage. The factors assessed in the two groups were: (1) time taken to achieve fusion; (2) neck disability index; (3) pain score; (4) interbody height ratio; (5) interbody angle and (6) the influence of smoking on fusion. No statistical difference was seen in the time taken to achieve fusion, neck disability index, interbody height ratio, or interbody angles. Smoking did not have any effect on the fusion process. The pain score was significantly lower in the tricortical graft group at six months. We conclude that both methods of fusion give similar results, although tricortical graft fusion is cheaper than cage fusion, and is more effective in reducing the pain score.     

A prospective study on the risk of glove fingertip contamination during draping in joint replacement surgery

Introduction

The aim of this prospective study was to investigate the risk of contamination of surgical gloves during preparation and draping in joint replacement surgery.

Methods

During 46 hip and knee replacement procedures, the gloves of orthopaedic consultants (n=5) and registrars (n=3) were assessed for contamination immediately after draping by impression of gloved fingers on blood agar. Contamination was evaluated by the surgeon’s grade, the type of procedure, the role of the assistant and the dominance of the hand.

Results

A total of 125 pairs of top gloves were examined (79 pairs from registrars and 46 pairs from consultants). Bacterial contamination was isolated on 19 pairs (15.2%) (16 pairs from registrars and 3 pairs from consultants, p=0.04). Coagulase negative staphylococci were the main isolates and contamination was considered low in all cases (1–5 colonies). Contamination was seen more on the dominant hand (16 gloves from dominant hands and 6 from non-dominant hands, p=0.04), on the index finger and thumb. More contaminated gloves were seen in hip arthroplasty procedures (16 pairs from total hip replacements vs 3 pairs from total knee replacements, p=0.02).

Conclusions

Contamination of glove fingertips during draping in joint replacement procedures is more likely to occur among junior surgeons, in hip rather than knee arthroplasty procedures and on the dominant hand. It is therefore essential that surgeons of different grades replace gloves used in draping to avoid exposing patients to the risk of infection.     

Rinsing morcellised bone grafts with bisphosphonate solution prevents their resorption. A prospective randomised double-blinded study

During revision total hip replacement using morcellised compacted bone allograft, 16 patients were randomised to receive a graft which had been rinsed in either an ibandronate solution or in saline. Patients were assessed by dual energy x-ray absorptiometry after operation and at 3, 6, 12 and 24 months. A region of interest between the tip of the femoral stem and the distal plastic plug was chosen to measure the changes in bone density over time. The study was double-blinded. In all the control patients the bone density decreased during the first three months and then remained constant at this lower level. A large proportion of the mass of the bone graft was lost. In contrast, all patients with grafts treated with bisphosphonate showed a slight increase in bone density. The difference between the groups was highly significant at all points in time. We conclude that rinsing the graft in a bisphosphonate solution prevents its resorption and may therefore reduce the risk of mechanical failure. The treatment is simple, inexpensive, and appears virtually free of risk.     

Vascular graft infection: an analysis of sixty-two graft infections in 2411 consecutively implanted synthetic vascular grafts

Among 2411 consecutive arterial reconstructions performed with synthetic prosthetic material in Denmark during a 4-year period, 62 patients (2.6%) developed graft infection. Graft infection occurred only when the groin had been incised. The incidence of infection and the spread of infection along the graft did not relate to the graft material used (Dacron velour, Dacron woven, polytetrafluoroethylene, and umbilical vein). Retrospective analysis disclosed predisposing or precipitating factors in 50 of the 62 cases; the most important seemed to be unsatisfactory surgical technique. Fifty-three percent of the graft infections occurred within 30 days. Gram-positive cocci were the most common pathogen. The 62 patients had been in the hospital for a mean of 90 days and had undergone an average of 1.4 operations for graft infections. Of the patients, 25.8% died and 30.6% underwent amputations. Vascular graft infection is still one of the major problems in vascular surgery; greater care should be taken to improve antiseptics, improve surgical technique, and establish a rational prophylactic antibiotic regimen. A prophylactic antibiotic regimen of a combination of cephalosporin and ampicillin is recommended.     

Evaluation of neointimal hyperplasia on tranilast-coated synthetic vascular grafts: an experimental study.

Tranilast is an antiallergic drug that interferes with proliferation and migration of vascular smooth muscle cell induced by platelet-derived growth factor (PDGF) and transforming growth factor-beta1 (TGF-beta1). We investigated the local effect of tranilast on neointimal hyperplasia using tranilast-coated prosthetic grafts. The inner sides of the thin-walled polytetrafluoroethylene (PTFE) grafts were coated with chitosan and tranilast containing chitosan solution. Wistar albino rats (32) were used in the study. Patches (1 x 2 mm) for vascular grafts were prepared. Three groups were tested: group 1 (n = 12; tranilast coated), group 2 (n = 10; adhesive-only film-layer-coated), and group 3 (n = 10; normal ePTFE patch grafts sutured to the carotid arteries of the rats). Recipient sites of the carotid arteries were excised 4 weeks after surgery. All sections were examined histologically for graft patency, thrombus formation, and neointimal thickness. Expression of PDGF, fibroblast growth factor, and TGF-beta1 on cross-sections of the neointima were evaluated by immunohistochemistry. No significant differences were found regarding mean neointimal thicknesses. PDGF and TGF-beta-1 expressions were significantly lower in group 1. Although a decrease in local effect of tranilast was observed for growth factor expressions at a drug concentration of 0.05 mg/cm(2), a significant reduction in neointimal hyperplasia was not achieved. The coating concentration of 0.05 mg/cm(2) may have been too low to produce an antiproliferative effect. Given our promising results, further studies are recommended and planned using different drug concentrations and time intervals.     

Hydronephrosis after aortofemoral bypass graft. A prospective study

This prospective study was designed to determine the frequency and natural history of hydroureteronephrosis (HUN) after placement of an aortobifemoral vascular graft. A total of 30 patients were evaluated by the study protocol, which included: pre and postoperative biological kidney function tests, preoperative and early postoperative (14th day) intravenous pyelograms and a late (mean 18th month) urologic examination by renal ultrasonic tomography. Four asymptomatic, early cases of HUN were observed in the 57 ureters examined (7%); all four complications regressed in less than 30 days. No cases of symptomatic early or late HUN were observed in this series. Asymptomatic early HUN was a frequent complication in our series (7%) but its benign course does not justify systematic screening. These asymptomatic complications contrast with the symptomatic cases of early or late HUN reported in the literature which necessitated urologic and vascular investigations.     

Prevention of neointimal proliferation by immunosuppression in synthetic vascular grafts.

OBJECTIVE: Immunosuppressive agents have been proposed to reduce neointimal hyperplasia in synthetic vascular grafts. Thus, the purpose of the present study was to evaluate the safety and efficacy of rapamycins (systemic vs. local vs. oral administration) and mycophenolate mofetil (MMF) to reduce intimal hyperplasia in infrarenal synthetic vascular grafts of the rat. METHODS: Fifty-four Wistar rats (250 g) completed the study after a synthetic vascular graft (ePTFE, Gore-tex, 2 mm diameter, 10 mm length) was implanted end-to-end in the infrarenal aorta. The animals were divided into three groups: group 1 consisted of 12 control animals, group 2 consisted of 37 rats receiving rapamycins, either per os (RAD, 1.5 or 3 mg/kg), intraperitoneally (RPM, 1.5 or 3 mg/kg) or locally (RPM soaking of the graft); and in group 3 (n=5), MMF (40 mg/kg) was administered orally. The animals were followed weekly with weight controls and signs of toxicity for 30 (n=37) and 60 (n=17) days, respectively. All animals were sacrificed and underwent histological examination at completion of the study. RESULTS: All animals survived in groups 1 and 3, but five died in group 2. The weight gain was normal in all groups, except for the subgroup 2a receiving high dose rapamycins orally. All rats in group 3 suffered from diarrhea, whereas animals receiving high dose rapamycins showed toxic signs (hair loss, wound healing problems). Histological examination showed a significant increase in intimal hyperplasia in group 1 (0.03+/-0.01 and 0.14+/-0.05 microm after 30 and 60 days, respectively; P<0.01). Rapamycins in either application or dosage had no significant effect on intimal hyperplasia. CONCLUSIONS: Local or systemic administration of rapamycins has no effect on intimal hyperplasia in synthetic vascular grafts. In contrast, toxic signs with weight loss were observed in animals treated with high dose rapamycins, but not in those treated with MMF. Thus, in the rat model, immunosuppression with rapamycins or MMF cannot be recommended for the prevention of intimal hyperplasia in the synthetic vascular graft model.     

A prospective study of 100 gelatin-sealed aortic grafts

A gelatin-sealed knitted Dacron graft has been developed which has zero porosity at Implantation and does not require preclotting. Its patency rate up to 57 months and effectiveness at saving blood loss have been studied. Gelatin-sealed aortic grafts were implanted into 100 consecutive patients-77 men, 23 women. Surgery was performed for aneurysm in 36 patients (including four with rupture), intermittent claudication in 44, rest pain in 17, and gangrene in three, over an 18 month period. The patients were followed up prospectively for 57 months. Perioperative mortality was 1%. Cumulative primary graft patency was 99%. There was no measurable blood loss at implantation. Forty-seven patients required blood transfusion: mean volume transfused was 430 ml. There were no problems related to the sealant.     

Incidence of glove perforations in gastrointestinal surgery and the protective effect of double gloves: a prospective, randomised controlled study.

OBJECTIVE: To investigate the incidence of glove perforations during various types of gastrointestinal surgery, to record the incidence of blood contamination of the hands, and to evaluate the protective effect of double gloving. DESIGN: Randomised prospective trial. SETTING: University hospital, Denmark. MATERIAL: 566 pairs of gloves tested on surgeons, assistants, and scrub nurses. INTERVENTIONS: The participants were allocated to wear either single gloves or Indicator double gloves. MAIN OUTCOME MEASURES: The number of glove perforations and the incidence of blood contamination of the hands. RESULTS: The perforation rate in single gloves was 53/306 (17%), and that of both outer and inner Indicator gloves at corresponding sites was 6/260 (2%) (p < 0.0001). Double gloving reduced the rate of blood contamination of the hands among surgeons from 15/115 (13%) to 2/98 (2%) (p < 0.005). CONCLUSION: The use of Indicator double gloves is recommended in gastrointestinal surgery because of the appreciable protection against blood contamination that they offer.     

Multislice CT in graft vascular disease. A pilot study

Introduction

Graft vessel disease (GVD) is one of the main long-term complications in heart transplant (HT) patients. At present, the diagnosis of this complication requires invasive procedures. Multislice CT is an emerging technique that allows visualization of the coronary anatomy, including the vascular lumen and wall thickness.Our objective was to establish the value of 16-detector multislice CT in the detection of GVD, compared with angiography and intravascular ultrasound (IVUS).

Patients and methods

We studied 32 HT patients, who had a mean follow-up of 2016 days. CT was performed 24 hours prior to angiography, associated with IVUS if the latter proved normal. Comparisons were subsequently made using contingency tables to establish the sensitivity, specificity, and predictive values of the CT.

Results

Angiography was not performed on two patients, and eight were excluded from CT assessment due to serum creatinine values >1.5 mg/dL. Comparison of the CT findings with the invasive techniques yielded a sensitivity of 50%, a specificity of 81%, a negative predictive value of 81%, a positive predictive value of 50%, and a precision of 72%.

Conclusions

Our results suggested good performance of the technique in screening for GVD because a high negative predictive value was recorded. We plan to increase the number of patients and use the 64-detector CT system to ensure greater time and spatial resolution.     

Role of topical antibiotics in hip surgery. A prospective randomised study

BACKGROUND: The effectiveness of topical antibiotics has been shown well enough in vitro to justify strong consideration of their use in orthopaedic procedures. We carried out a randomised prospective trial to study the role of topical chloramphenicol ointment application on postoperative wounds following surgeries for hip fractures. METHODS: One hundred cases with fracture neck of femur were enrolled in the study. They were randomized into two treatment groups: one group had chloramphenicol ointment applied at the surgical site at the end of procedure and 3rd day postoperatively, while the control group did not. The wound was checked on the 3rd, 6th, 12th and 30th days postoperatively, by a tissue viability nurse on the guidelines issued by the Scottish Centre for Infection and Environmental Health (SCIEH). RESULTS: We had 12 cases with superficial infection of which 8 belonged to control group. The risk of developing wound infection, however, was not significant with and without the use of chloramphenicol ointment (relative risk 0.430, 95% confidence interval (CI) 0.120-1.544). Using multivariate analysis, no association was found between wound infection and age, gender, type of fracture or type of surgical procedure. Smoking was found to be the only factor significantly associated with infection, with the relative risk for current smokers compared with former/non-smokers being 7.29 (95% CI 1.62-32.67). CONCLUSION: Awareness is needed amongst the general public about the ill effects of smoking. There was reduction in the incidence of wound infection with the use of topical antibiotic ointment. However, this was not statistically significant to recommend its use in routine practice. A larger study should provide useful information on the role of topical antibiotic and its effect on postoperative wound infection.     

A prospective randomised comparative parallel study of amniotic membrane wound graft in the management of diabetic foot ulcers

Our purpose was to compare healing characteristics of diabetic foot ulcers treated with dehydrated human amniotic membrane allografts (EpiFix®, MiMedx, Kennesaw, GA) versus standard of care. An IRB‐approved, prospective, randomised, single‐centre clinical trial was performed. Included were patients with a diabetic foot ulcer of at least 4‐week duration without infection having adequate arterial perfusion. Patients were randomised to receive standard care alone or standard care with the addition of EpiFix. Wound size reduction and rates of complete healing after 4 and 6 weeks were evaluated. In the standard care group (n = 12) and the EpiFix group (n = 13) wounds reduced in size by a mean of 32·0% ± 47·3% versus 97·1% ± 7·0% (P < 0·001) after 4 weeks, whereas at 6 weeks wounds were reduced by ?1·8% ± 70·3% versus 98·4% ± 5·8% (P < 0·001), standard care versus EpiFix, respectively. After 4 and 6 weeks of treatment the overall healing rate with application of EpiFix was shown to be 77% and 92%, respectively, whereas standard care healed 0% and 8% of the wounds (P < 0·001), respectively. Patients treated with EpiFix achieved superior healing rates over standard treatment alone. These results show that using EpiFix in addition to standard care is efficacious for wound healing.     

Practical considerations in fabric vascular grafts. Introduction of a new bifurcated graft

A new bifurcation graft is introduced which conforms to the anatomic requirements of the aortoiliac segment. The graft material is made of 70 denier Dacron fiber manufactured in a warp-knit to prevent excessive fraying and to decrease porosity. Porosity studies indicate that the new material is approximately half as porous as other available Dacron graft materials. The new graft sizes of 12 by 7 and 14 by 8 mm more closely approximate the human aorta and common iliac arteries than do other available standard bifurcation grafts.The new bifurcation prosthesis has been used as an arterial bypass graft in 135 patients requiring surgery for aortoiliac occlusive disease. Of these patients, 64 per cent did not require blood replacement during surgery. The early operative results are comparable with those of other reported series.     

Proximally cemented versus uncemented Freeman-Samuelson knee arthroplasty. A prospective randomised study.

We studied the effect of a layer of cement placed under the tibial component of Freeman-Samuelson total knee prostheses with a metal back and an 80 mm intramedullary stem, using roentgen stereophotogrammetry to measure the migration of the tibial component during one year in 13 uncemented and 16 cemented knees. The addition of cement produced a significant reduction in migration at one year, from a mean of 1.5 mm to one of 0.5 mm (p less than 0.01), including a significant reduction in pure subsidence. One year postoperatively the clinical results were similar between the groups, but, at three years, one uncemented knee had required revision.     

The tourniquet in total knee arthroplasty. A prospective, randomised study

We assessed the influence of the use of a tourniquet in total knee arthroplasty in a prospective, randomised study. After satisfying exclusion criteria, we divided 77 patients into two groups, one to undergo surgery with a tourniquet and one without. Both groups were well matched. The mean change in knee flexion in the group that had surgery without a tourniquet was significantly better at one week (p = 0.03) than in the other group, but movement was similar at six weeks and at four months. There was no significant difference in the surgical time, postoperative pain, need for analgesia, the volume collected in the drains, postoperative swelling, and the incidence of wound complications or of deep-venous thrombosis. We conclude that the use of a tourniquet is safe and that current practice can be continued.     

Postoperative autologous transfusion in cardiac surgery. A prospective, randomised study

To investigate the safety and efficacy of postoperative autologous blood transfusion (AT) using the Shiley hardshell venous reservoir, a prospective, randomised, controlled study was carried out in two matched groups of twenty patients undergoing elective coronary artery bypass surgery. The mean volume of shed mediastinal blood reinfused in the first 6 h postoperatively was 371.7 +/- 63.23 ml. Use of homologous blood was reduced from 760.5 +/- 108.37 ml in the control patients to 466.25 +/- 87.44 ml in the AT patients, a reduction of 38.7% (p less than 0.05). There was no statistically significant difference in the clinical outcome, overall blood loss, use of platelets, fresh frozen plasma and colloids, haematological indices, renal and hepatic functions, or clotting mechanism, although there was a reduction in the fibrinogen level in the patients who received AT (p less than 0.05). Mediastinal blood did not clot and was defibrinogenated. It contained significant levels of haemoglobin (8.175 +/- 0.506 g/dl), platelets (96.55 +/- 10.39 per mm3 10(3)), protein (42.5 +/- 1.13 g/l), calcium (2.385 +/- 0.054 mmol/l) and was well oxygenated (PO2 = 20.46 +/- 0.81 kPa). No patients developed bacteraemia or had any AT-related infections. We conclude that postoperative autologous transfusion using the Shiley hardshell venous reservoir is a safe and efficient method for reducing postoperative homologous blood requirement after coronary artery bypass surgery.