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Biomedical subjects

G T Rodeheaver

Publications and source records attributed to G T Rodeheaver.

At least 37 records · Page 2Linked to original sources
PubMed1997

A new stable pluronic F68 gel carrier for antibiotics in contaminated wound treatment.

Pluronic F68 was selected as the gel carrier for antimicrobial agents because of its extensive use as a wound cleanser in humans without discernable side effects. When the concentration of this surfactant is increased to 46%, it forms a water soluble gel that can serve as a carrier for antimicrobial agents. The stability of this gel can be enhanced by immediately cooling (-15 degrees C) the gel for 24 hours before storage and subsequent application. Immediate cooling of the gel causes hydration of the surfactant that is associated with gel strengthening and prolonged shelf life stability. In experimental animals, this stable gel carrier containing 0.2% nitrofurazone significantly reduces the bacterial concentration of Staphylococcus aureus in wounds to a greater degree than silver sulfadiazine. This antimicrobial gel has the same antimicrobial activity as polyethylene glycol carriers containing 0.2% nitrofurazone, but does not carry the potential risk of polyethylene glycol intoxication.

Animals↗
PubMed1997

A technique for quantifying the performance of oscillating bone saw blades.

A new model has been developed to evaluate the performance of oscillating surgical saw blades used in medical-implant procedures. A test apparatus was constructed to maintain a constant cutting force between a blade driven by a pneumatic powered oscillating saw and the bone. Evaluations of saw-blade performance were determined using the following outcome measures: cutting time, volume of bone removal, and peak cutting temperature. Two popular, commercially available blades similar in size and tooth geometry were evaluated. This model identified differences in the performance of these two types of oscillating saw blades.

Animals↗
PubMed1997

Durability of oscillating bone saw blades.

The purpose of this study was to measure the durability of disposable saw blades using a standard bone-cutting experimental model that can be replicated in any laboratory. Using a constant cutting force, the bone-cutting efficiency was determined by recording the maximum cutting temperature and the rate of material removal. In this experimental study, porcine femurs as well as a synthetic bone substitute were used as the test samples for measuring cutting efficiency. Repeated cutting of these test materials did not significantly alter the performance of the disposable bone-cutting blades.

Animals↗
PubMed1997

Innovations in oscillating bone saw blades.

The purpose of this study was to identify some of the determinants of saw-blade design that influence bone-cutting performance. Using a reproducible experimental model, saw-blade performance was judged by measuring the blade temperature and the rate of bone removal. The results of this study demonstrated that the rake angle and blade swing radius had significant influence on saw-blade performance.

Animals↗
PubMed1997

Pressure ulcer scale for healing: derivation and validation of the PUSH tool. The PUSH Task Force.

Measuring progress toward healing is fundamental to the management of pressure ulcers. A method to assess progress of an individual ulcer over time is lacking. Given the limitations of currently available instruments and the need for a precise and practical method of monitoring healing in clinical practice, the National Pressure Ulcer Advisory Panel initiated the development of a new tool for measuring pressure ulcer healing. The key elements in developing an instrument include simplicity of use in clinical settings, validity for measuring whether ulcers are improving or worsening, and sensitivity to changes in the ulcer between observations. A new tool incorporating surface area, exudate amount, and surface appearance is proposed. Content validity, correlation validity, prospective validity, and sensitivity to change can be met by the proposed Pressure Ulcer Scale for Healing instrument.

Humans↗
PubMed1996

Role of ischemic gradient in neovascularization of interpolated skin flaps.

OBJECTIVES: To investigate the significance of the ischemic gradient between interpolated skin flaps and the recipient bed and to determine its role in flap viability. DESIGN: Bilateral interpolated skin flaps were elevated in 10 pigs and intravenous fluorescein was used to define a border of pedicle perfusion. Flaps were assigned to 1 of 2 groups: proximal flaps, which were contained within the fluorescein border, or distal flaps, which extended 3 cm beyond the fluorescein border. Flaps were then transferred to an adjacent cutaneous defect and pedicles were divided after 2 weeks. The flap and pedicle portions were evaluated separately and viability was quantified. SUBJECTS: Ten adolescent pigs with bilateral flaps. None were withdrawn. INTERVENTION: Intravenous fluorescein (20 mg/kg) to determine extent of perfusion in the flaps. RESULTS: Proximal flaps (n = 10) maintained excellent viability with the pedicles attached. After pedicle division, however, partial flap and pedicle necrosis developed. Distal flaps (n = 10) promptly showed signs of ischemia and congestion but soon showed improved vascularity. A statistically significant improvement was seen in mean percent viability of the distal group compared with the proximal group (P < .05) (Student t test). CONCLUSION: The more ischemic flap-pedicle complex resulted in greater viability after pedicle division. The ischemic gradient seemed to represent a potent angiogenic stimulus to the recipient bed.

Animals↗
PubMed1996

Knot performance of polypropylene sutures.

A mechanical performance test using an Instron Tensile Tester demonstrated the superior handling characteristics of Surgipro suture as compared to Prolene suture that facilitated knot construction without suture breakage. For both granny and square knots, the knot run down forces for the Surgipro sutures were significantly less than those encountered for comparable knots for Prolene sutures. This propensity of the two-throw knots of Surgipro sutures to advance without breakage considerably facilitated knot construction.

Materials Testing↗
PubMed1996

Seroma prevention in a rat mastectomy model: use of a light-activated fibrin sealant.

Seroma formation following mastectomy and axillary dissection remains a common and significant problem contributing to patient morbidity and health-care costs. Previous data have suggested that fibrin sealant (FS), a biological adhesive, is capable of controlling lymphatic leakage and assisting with skin graft adhesion. In this study, the use of an experimental, light-activated FS under development by CryoLife (CFS) was evaluated in a rat mastectomy model in order to reduce seroma formation. CFS is a premixed form of FS, containing an inactivator that is reversed in the presence of light, causing sealant to form. In this model, rats underwent mastectomy and extensive dissection of the axillary lymphovasculature. Next, 1 ml of saline or FS was applied to the operative site and the wound was closed. Three groups of animals were evaluated 5 days postoperatively by measuring the volume (in milliliters) of seroma able to be aspirated from the surgical site. The saline control group (N = 20) had a seroma volume (mean +/- standard deviation [SD]) of 4.2 +/- 2.9 ml, while a form of CFS containing human fibrinogen (80 to 100 mg per milliliter) and human thrombin (20 U per milliliter) (N = 20) had a significantly smaller seroma volume of 1.1 +/- 1.6 ml (p < 0.001 analysis of variance). University of Virginia (UVA) FS, containing human fibrinogen (20 mg per milliliter) and bovine thrombin (500 U per milliliter) (N = 20), had a seroma volume of 2.0 +/- 1.6 ml (p < 0.01, compared to control; p > 0.2, compared to CFS). Thus, this form of CFS significantly reduced seroma formation compared to saline control and also appeared to result in a smaller fluid accumulation than with UVA FS, although this trend was not statistically significant. These data suggest that the use of CFS may help to reduce seroma formation in humans.

Animals↗
PubMed1996

Biomechanical and clinical performance of a new synthetic monofilament absorbable suture.

The clinical and mechanical performance of a new, monofilament, synthetic absorbable suture (Biosyn) was evaluated and compared to that of a braided synthetic absorbable suture (Vicryl). The monofilament synthetic absorbable suture was significantly stronger than the braided synthetic absorbable suture over the 4 weeks of implantation. In addition, the monofilament suture potentiated less bacterial infection than did the braided suture. The handling characteristics of the monofilament suture were superior to the braided suture because the monofilament suture required fewer throws to achieve knot security, encountered lower drag forces in fascia and colon, and had a greater double-wrapped first-throw knot security. Evaluated independently in clinical settings, the monofilament sutures were found to have excellent strength, first-throw hold, knot security, passage through tissue, knot repositioning, and ease of handling.

Abdominal Muscles↗
PubMed1995

Analysis of the kinetics of peritoneal adhesion formation in the rat and evaluation of potential antiadhesive agents.

BACKGROUND: Peritoneal adhesions continue to be a significant cause of postoperative complications. Elucidating the origin of these adhesions has been hampered by the lack of a reproducible animal model. The purpose of this study was to create a standardized model in which a single, specific adhesion could be objectively measured. With this model the kinetics of adhesion formation were then evaluated. A variety of potential antiadhesive agents were then tested and compared. METHODS: In this study a reproducible, quantitative rat model was developed that used uniform defects on the peritoneal wall and cecal surface. The resulting adhesions were subsequently scored, and their strength was measured with a tensiometer. An evaluation of the kinetics of peritoneal adhesion formation was obtained by using a timed removal of silicone elastomer sheeting held between the two injured surfaces. The following antiadhesive agents were evaluated: Ringer's lactate solution; dextran 70 (32%); modified carboxymethylcellulose (1.0% and 2.0%); an absorbable barrier of specially knitted material composed of oxidized regenerated cellulose; fibrin sealant; silicone elastomer film; and expanded polytetrafluoroethylene membrane. RESULTS: Evaluation of the kinetics of peritoneal adhesion formation indicated that the susceptibility for adhesion formation was significantly decreased or eliminated after the first 36 hours. Evaluation of antiadhesion agents indicated that the magnitude of adhesion prevention was directly proportional to the agent's ability to remain at the site of injury during the critical period of adhesion formation. Permanent barriers (silicone elastomer film, expanded polytetrafluoroethylene membrane) provided the greatest antiadhesion effect but were not believed to be ideal agents because they remained at the site of injury well after the critical period of adhesion formation. The incidence of adhesion formation for the other agents was as follows: control (34 of 34), Ringer's lactate (12 of 12), absorbable barrier of knitted cellulose (10 of 10), 32% dextran 70 (8 of 12), 1% carboxymethylcellulose (6 of 12), fibrin sealant (4 of 9), and 2% carboxymethylcellulose (4 of 12). CONCLUSIONS: The efficacy of antiadhesion agents appears to be related to the agent's viscosity, ability to coat the wound surface, and residence time at the site of injury. In this rat model an agent that remained on the injured surfaces for at least 36 hours after injury appeared to be more effective in reducing adhesion formation than an agent with a shorter residence time.

Animals↗
PubMed1995

Wound cleansing by irrigation for implant surgery.

Wound irrigation is an adjunct to all implant surgeries involving surgical incisions or arthroplasties. An understanding of the physics of wound irrigation provides a scientific basis for recommending wound irrigation systems for implant surgery. When inserting implants through surgical incisions, a low-pressure irrigation system is recommended for removing blood from the wound surface. In contrast, high-pressure irrigation systems are indicated to cleanse the intramedullary canal before cemented arthroplasty. With the advent of static and dynamic pressure transducers, irrigation systems can now be specifically designed to achieve these goals.

Animals↗
PubMed1994

Evaluation of new absorbable Lactomer subcuticular staple.

The most recent advance in skin sampling is the Auto Suture SQS -20 disposable stapler. It approximates and everts wound edges, placing one synthetic absorbable pin in the dermis each time the instrument handle is activated. Staple wound closure was accomplished four times faster than sutural closure of the dermis. Wounds with staple pin closure exhibit superior resistance to infection than wounds approximated by dermal sutures. Although sutures provide more immediate wound security, as measured by wound breaking strength, than dermal pins, the breaking strength of wounds subjected to either dermal pins or dermal sutures were not significantly different 14 days after wounding.

Equipment Design↗
PubMed1994

Quantitation of force to dislodge endoscopic ligation clips: EndoClip II vs. Ligaclip ERCA.

The mean forces required to dislodge two types of endoscopic ligation clips from both porcine cystic ducts and silicone tubing were quantitated. The two types of endoscopic clips were EndoClip II and Ligaclip ERCA. Following application of the clips, the force required to dislodge the clips in both a perpendicular direction and a longitudinal direction was determined. The mean levels of force required to dislodge the EndoClip II clips in both directions were significantly (p < or = 0.01) greater than those required to dislodge the Ligaclip ERCA clips.

Animals↗
PubMed1994

Some biomechanical considerations in microsutures.

The purpose of this study was to measure the biomechanical performance for commercially available microsutures, nylon polypropylene, polyester, and polyglactin 910. The biomechanical performance was determined by reproducible, biomechanical parameters that included stiffness, elasticity, resistance to creep, secure knot construction, and knot breaking strength. On the basis of these comprehensive studies, the handling characteristics of the nylon microsutures were judged to be superior over the other microsutures. Knot security was achieved with a three-throw square (1 = 1 = 1) knot that allowed a preview of the ultimate apposition of the divided tissue. In addition, nylon microsutures were more supple than the other microsutures. The breaking strength of the knotted nylon microsutures was comparable with those of the knotted polyglactin 910 and polyester microsutures, and significantly greater than that of the knotted polypropylene sutures. Its resistance to creep was significantly greater than that of the polypropylene microsutures but less than those of polyglactin 910 and polyester microsutures.

Biomechanical Phenomena↗
PubMed1994

A new device for securing meshed split-thickness skin grafts.

This report describes the design, operation, and biomechanical performance of the Auto Suture Multifire Graftac-S disposable surgical staplers and absorbable tacks. The performance of this reloadable stapler has been compared to that of the Auto Suture Multifire Premium disposable skin stapler. The Premium stapler forms stainless steel staples to close the wound. The Graftac-S ejects absorbable tacks into the graft from a cartridge, which can be reloaded during a single operation. In two clinical trials of 10 patients each, the Graftac-S delivered absorbable tacks which were biocompatible and successfully secured the graft to the wound. The most obvious advantage of this device is that it obviates the need to remove the staples from the wound later. By the tenth postoperative day, about 90% of the tacks had extruded spontaneously, thereby reducing the amount of postoperative care required; discomfort to the patient during removal of the stainless steel staples is eliminated.

Biocompatible Materials↗