Lawrence Zachary

Acute effects of tobacco smoking on blood flow in the cutaneous micro-circulation

p6 experimental model has been designed to help study the acute effects of tobacco smoking on the cutaneous micro-circulation. Arterioles in the nude mouse ear are directly visualised by intravital microscopy and the blood flow is quantified. Arteriolar vasoconstriction and decreased blood flow are seen in response to smoking. The implications of post-operative smoking for the patient undergoing flap surgery are discussed.

Prosthesis placement after total phallic reconstruction.

Total reconstruction of the phallus is now technically feasible. The successful reestablishment of sexual function in these patients is possible using the neurosensory radial forearm flap. The innervated neophallus develops tactile and erogenous sensation within 4 to 6 months of neurorrhaphy. Unperceived chronic pressure with subsequent tissue ischemia is the leading cause of delayed prosthesis extrusion. The development of protective sensation within this reconstructed neophallus allows for the safe placement of a penile prosthesis permitting intromission. The development of erogenous sensation allows for orgasm. We report on the successful implantation and long-term retention of penile prostheses in 4 patients after total phallic reconstruction.

The radial forearm skin graft-fascial flap.

The radial forearm flap has become a versatile flap for upper extremity reconstruction. The use of the forearm flap for hand reconstruction in the patient with previously burned forearms has not been widely appreciated. In those patients whose forearms have been previously split-thickness skin-grafted on fascia, we have employed the reverse radial forearm flap as a skin graftfascial flap for hand reconstruction and have obtained excellent functional results. Three patients at various intervals postburn are presented to demonstrate use of this flap for wrist contracture release, coverage of arthroplasties, first web space contracture release, and acute salvage of halanges and tendons. Assessment of the ands vascular anatomy and careful treatment of the donor area have contributed to no added morbidity and an excellent aesthetic result at the donor site.

Endogenous versus Toxin-induced Diabetes in Rats: A Mechanical Comparison of Two Skin Wound-healing Models

This study was designed to compare skin wound healing in three groups of Wistar rats: normal, genetically diabetic, and streptozotocin-induced diabetic. All diabetic animals received daily insulin. Full-thickness mid-line dorsal skin wounds were analyzed biomechanically for strength, toughness, and elasticity (Youngs modulus) at 1 and 3 weeks after wounding. Wounds from normal controls were the strongest, toughest, and least compliant. Genetically diabetic rat wounds were the weakest and had the lowest elastic modulus. Wounds from the streptozotocin-induced rats were intermediate for all parameters measured (ANOVA, p = 0.001). Toxin-induced diabetes is less detrimental to skin wound healing than diabetes of endogenous origin. Whether this is due to basic differences in the models or to differences in duration of diabetes is unknown.

Improved imaging of rat hindfoot prints for walking track analysis

Walking track analysis is an investigative technique that allows a researcher to assess objectively the functional capacity of the limb in the rat sciatic nerve model. This study has shown that paint and paper is a better method for imaging the rat foot plantar surface than other methods described in the literature. The block printing paint has the distinct advantage of keeping radial diffusion error to a minimum. Paint more correctly images the important anatomical landmarks of the rat plantar surface. There is better traction (less slippage) rendering the prints easier to interpret. The authors conclude that the paint and paper is a superior method to the other methods currently available.

The use of quantitative bacteriologic assessment of bone.

&NA; The purpose of this paper was to examine whether quantitative bacteriologic assessment of bone is a reliable indicator of the adequacy of debridement of draining wounds involving bone. This is a retrospective review of 31 consecutive patients treated for draining posttraumatic/surgical wounds involving bone. Nineteen patients met the necessary criteria and were included in the study. These patients underwent radical debridement of bone and soft tissue, intraoperative assessment of the debrided wound by rapid slide quantitative bacteriologic assessment, and closure with well‐vascularized tissue. Clinical assessment of vascularity and rapid slide quantitative bacteriologic assessment of cancellous bone and soft tissue were the only prerequisites used in determining the appropriateness of wound closure in this study. At the time of most recent follow‐up, none of the 19 patients had recurrent wound drainage. Two patients required a second procedure to partially elevate their flaps and drain recurrent soft‐tissue infections. None of the patients had recurrence of bony infection. Seventeen patients who presented initially with fractures or osteotomies all had successful bone unions. This study demonstrates that the technique of rapid slide quantitative bacteriologic assessment of cancellous bone is a useful adjunct to surgical judgment and allows one to close draining wounds (frequently with complex wound closure options) with a high level of confidence. (Plast. Reconstr. Surg. 100: 397, 1997.)

Distribution of pedal burns by source and depth

The source and depth relationships of both isolated burns to the feet and pedal burns as part of multifocal thermal trauma are evaluated. Five years of cases at the University of Chicago Burn Center were selected at random and retrospectively reviewed. There were 33 isolated burns of the foot, with a source distribution of 70% scald, 9% grease, 9% hot solid, 6% flame, and 6% other. In patients with multifocal burns that included that foot, there were 89 cases, with a source distribution of 42% scald burns, 5% grease, 2% hot solid, 39% flame, 5% electrical, 1% frostbite, and 6% other. Source versus depth and grafting needs are presented. Admission to hospital which was delayed from the date of burn showed an increased need for grafting and a longer hospitalization than those admitted on the same day. Immediate admission for compliance of proper treatment protocol is advocated. Isolated pedal burns were most commonly sustained at home, indoors, and in the kitchen. A significant number of isolated burns to the feet were from a scald source, partial thickness in depth, and required no grafting. Much of the wound management involved treating elements found in traumatic, dysvascular, and diabetic pedal lesions.

Evaluation of changes in skeletal muscle blood flow in the dog with contrast ultrasonography

Intraoperative methods to assess skeletal muscle blood flow or muscle-flap perfusion during vascular reconstructive surgery are limited. At present, techniques enable only anatomic identification of the degree of patency of large vessels. We report here the first use of ultrasonography to assess dynamic changes in skeletal muscle perfusion. Baseline blood flow in the adductor muscle group of the hindlimbs of seven dogs was measured with an electromagnetic flow probe and with contrast ultrasound using the contrast agent Albunex. Blood flow was manipulated in each dog pharmacologically with random administration of intraarterial injections of Neo-Synephrine and papaverine. After each change in blood flow detected by electromagnetic flow probe, flow also was assessed qualitatively by four independent observers who graded video-recorded contrast enhancement in the muscle group on a 0 to 4 scale. Videodensitometry also was used to generate time versus intensity curves in the adductor muscle region of interest. Peak pixel intensity was determined during each flow condition. A total of 21 flow measurements were made with each assessment scheme (electromagnetic flow probe, video enhancement, videodensitometry) for each condition (7 control, 7 papaverine, 7 Neo-Synephrine). Changes in blood flow assessed by video enhancement scores and changes in peak pixel intensity correlated with changes measured by electromagnetic flow probe (r = 0.84 and 0.66, respectively). We conclude that contrast ultrasound may be used to detect changes in skeletal muscle perfusion intraoperatively. Measures of muscle perfused by visual inspection of contrast enhancement and videodensitometric data were in agreement with direct measurements of changes in skeletal muscle blood flow.

Increased Whole Blood Viscosity Is Associated with the Presence of Digital Ulcers in Systemic Sclerosis: Results from a Cross-Sectional Pilot Study

Objective To investigate the role of whole blood viscosity in digital ulcer (DU) development in patients with diffuse and limited Systemic sclerosis. Methods A convenience sample of patients with Systemic sclerosis (SSc) was selected from the adult Rheumatology clinic at the University of Chicago. The study group consisted of patients with SSc (with ulcers present, a history of ulcers, and no ulcers); the control group consisted of matched healthy Rheumatology clinic staff. WBV was measured using a scanning capillary viscometer at different shear rates (1–1000u20091/s). Results Whole blood viscosity as measured by a scanning capillary viscometer was increased in patients with SSc compared to healthy controls (p < 0.0001). Additionally, patients with present DU had significantly higher whole blood viscosity when compared to patients with a history of DU and patients with no history of DU (p < 0.0001). These findings were most pronounced at lower shear rates between 1 and 10u20091/s. Conclusion Whole blood viscosity might be a contributing factor in DU development in patients with SSc. Further studies with larger patient cohorts are required to fully evaluate how increased WBV contributes to the development of DU and whether the currently available treatment options improve the microcirculation by influencing WBV.

Autologous staged fat tissue transfer in post-traumatic lower extremity reconstruction

Autologous fat tissue transfer for aesthetic reconstruction has been described in the literature for soft tissue damage as early as 1893. One area that has yet to be described is the role of fat grafting in post-traumatic lower extremity injuries. In this case report, we present a patient who had significant injury to her right lower extremity and presented for reconstruction. The patient is a 52-year-old female who presented to clinic after a right lower extremity traumatic injury that required multiple re-operations, which lead to dense scarring and volume loss along the extremity inferior to the knee joint. The patient received two staged autologous fat injections and reported positive outcomes. Our case report demonstrates the utility of fat transfer in reconstruction of the lower extremity in staged fashion. Further research in the refinement of this technique and patient follow-up will lead to better graft survival and reconstructive outcomes.