Alyssa J. Reiffel

Therapeutic delivery of hydrogen sulfide for salvage of ischemic skeletal muscle after the onset of critical ischemia

BACKGROUND Recent evidence suggests that hydrogen sulfide is capable of mitigating the degree of cellular damage associated with ischemia-reperfusion injury (IRI). METHODS This study evaluated the potential utility of hydrogen sulfide in preventing IRI in skeletal muscle by using in vitro (cultured myotubes subjected to sequential hypoxia and normoxia) and in vivo (mouse hind limb ischemia, followed by reperfusion) models to determine whether intravenous hydrogen sulfide delivered after the ischemic event had occurred (pharmacologic postconditioning) conferred protection against IRI. Injury score and apoptotic index were determined by analysis of specimens stained with hematoxylin and eosin and terminal deoxynucleotide transferase-mediated deoxy-uridine triphosphate nick-end labeling, respectively. RESULTS In vitro, hydrogen sulfide reduced the apoptotic index after 1, 3, or 5 hours of hypoxia by as much as 75% (P = .002), 80% (P = .006), and 83% (P < .001), respectively. In vivo, hydrogen sulfide delivered after the onset of hind limb ischemia and before reperfusion resulted in protection against IRI-induced cellular changes, which was validated by significant decreases in the injury score and apoptotic index. The timing of hydrogen sulfide delivery was crucial: when delivered 20 minutes before reperfusion, hydrogen sulfide conferred significant cytoprotection (P < .001), but treatment 1 minute before reperfusion did not provide protection (P = NS). CONCLUSIONS These findings confirm that hydrogen sulfide limits IRI-induced cellular damage in myotubes and skeletal muscle, even when delivered after the onset of ischemia in this murine model. These data suggest that when given in the appropriate dose and within the proper time frame, hydrogen sulfide may have significant therapeutic applications in multiple clinical scenarios.

Perioperative Antibiotics in the Setting of Microvascular Free Tissue Transfer: Current Practices

Microvascular free tissue transfer is a ubiquitous and routine method of restoring anatomic defects. There is a paucity of data regarding the role of perioperative antibiotics in free tissue transfer. We designed a survey to explore usage patterns among microvascular surgeons and thereby define a standard of care. A 24-question survey regarding the perioperative antibiotic use in microvascular head and neck, breast, and lower extremity reconstruction was sent to all those members of the American Society for Reconstructive Microsurgery who had registered e-mail addresses ( N = 450). Ninety-nine members responded. A first-generation cephalosporin is the most frequent choice of perioperative antibiotics across most categories: 93.5% for breast, 59.2% for head and neck, 91.1% for nontraumatic lower extremity, and 84.9% for traumatic noninfected lower extremity reconstruction. In penicillin-allergic patients, clindamycin is the most common choice. For traumatic lower extremity reconstruction in the presence of soft tissue infection or osteomyelitis, culture and sensitivity results determine the selection of perioperative antibiotics in 74%. A first-generation cephalosporin is the standard of care for perioperative antibiotic use in microvascular breast, head and neck, nontraumatic lower extremity, and traumatic noninfected lower extremity reconstruction. No consensus exists regarding the appropriate duration of coverage. These data may serve as a guide until a large controlled prospective trial is performed and a standard of care is established.

Mathematical modeling and frequency gradient analysis of cellular and vascular invasion into integra and strattice: toward optimal design of tissue regeneration scaffolds.

Background: Rapid, effective host cell invasion and vascularization is essential for durable incorporation of avascular tissue-replacement scaffolds. In this study, the authors sought to qualitatively and quantitatively determine which of two commercially available products (i.e., Strattice and Integra) facilitates more rapid cellular and vascular invasion in a murine model of graft incorporation. Methods: Integra and Strattice were implanted subcutaneously into the dorsa of C57BL/6 mice; harvested after 3, 7, or 14 days; and stained with hematoxylin and eosin, 4′,6-diamidino-2-phenylindole, and immunohistochemical stains for CD31 and &agr;-smooth muscle actin. Exponential decay equations describing cellular invasion through each layer were fit to each material/time point. Mean cell density and cell frequency maps were created denoting extent of invasion by location within the scaffold. Results: Qualitative analysis demonstrated extensive cellular infiltration into Integra by 3 days and increasing over the remaining 14 days. Invasion of Strattice was sparse, even after 14 days. &agr;-Smooth muscle actin immunohistochemistry revealed blood vessel formation within Integra by 14 days but no analogous neovascularization in Strattice. Mean decay equations for Integra and Strattice were y = 76.3(0.59)x and y = 75.5(0.33)x, respectively. Both cell density measurements and frequency mapping demonstrated that, at all time points, Integra manifested a greater density/depth of cellular invasion when compared with Strattice. Conclusions: These data confirm empiric clinical observations that Integra is more rapidly invaded than Strattice when placed in a suitable host bed. A remnant microvasculature template is not sufficient for effective cellular ingrowth into an artificial tissue construct. These findings provide insight into means for improving future dermal replacement products.

A Prospective Analysis of the Association Between Indwelling Surgical Drains and Surgical Site Infection in Plastic Surgery

IntroductionMany surgeons fear that closed-suction drains serve as a portal for bacterial entry into surgical spaces. Despite a lack of supporting evidence, postoperative antibiotics are often prolonged while drains remain in place. MethodsMedical records of all patients who underwent intraoperative Jackson-Pratt drain placement and sterile removal over a 12-month period were prospectively analyzed. ResultsFifty-four patients with 101 drains were included. Drains were in place for 5 to 43 days [mean (SD), 13.5 (6.3) days]. Sixty-three percent of drains had positive cultures. All patients received perioperative antibiotics. Thirty-nine patients received postoperative antibiotics [mean (SD), 13.8 (13.8) days]. There were 2 cases of cellulitis. One patient required reoperation. ConclusionsSixty-six drains (65.3%) were placed in the presence of prosthetic material. Although nearly two thirds of drains were colonized with bacteria, our wound infection rate was extremely low (5.6%). Thus, closed-suction drains may be left in place for an extended period without increasing the risk of infection, even in the presence of prosthetic material.

Hydrogen sulfide reduces neutrophil recruitment in hind-limb ischemia-reperfusion injury in an L-selectin and ADAM-17-dependent manner.

Background: Reperfusion following ischemia leads to neutrophil recruitment into injured tissue. Selectins and &bgr;2-integrins regulate neutrophil interaction with the endothelium during neutrophil rolling and firm adhesion. Excessive neutrophil infiltration into tissue is thought to contribute to ischemia-reperfusion injury damage. Hydrogen sulfide mitigates the damage caused by ischemia-reperfusion injury. This studys objective was to determine the effect of hydrogen sulfide on neutrophil adhesion receptor expression. Methods: Human neutrophils were either left untreated or incubated in 20 &mgr;M hydrogen sulfide and/or 50 &mgr;g/ml pharmacologic ADAM-17 inhibitor TAPI-0; activated by interleukin-8, fMLP, or TNF-&agr;; and labeled against P-selectin glycoprotein ligand-1, leukocyte function associated antigen-1, Mac-1 &agr;, L-selectin, and &bgr;2-integrin epitopes CBRM1/5 or KIM127 for flow cytometry. Cohorts of three C57BL/6 mice received an intravenous dose of saline vehicle or 20 &mgr;M hydrogen sulfide with or without 50 &mgr;g/ml TAPI-0 before unilateral tourniquet-induced hind-limb ischemia for 3 hours followed by 3 hours of reperfusion. Bilateral gastrocnemius muscles were processed for histology before neutrophil infiltration quantification. Results: Hydrogen sulfide treatment significantly increased L-selectin shedding from human neutrophils following activation by fMLP and interleukin-8 in an ADAM-17–dependent manner. Mice treated with hydrogen sulfide to raise bloodstream concentration by 20 &mgr;M before ischemia or reperfusion showed a significant reduction in neutrophil recruitment into skeletal muscle tissue following tourniquet-induced hind-limb ischemia-reperfusion injury. Conclusions: Hydrogen sulfide administration results in the down-regulation of L-selectin expression in activated human neutrophils. This leads to a reduction in neutrophil extravasation and tissue infiltration and may partially account for the protective effects of hydrogen sulfide seen in the setting of ischemia-reperfusion injury.

Use of Integra and interval brachytherapy in a 2-stage auricular reconstruction after excision of a recurrent keloid.

Abstract Keloids present a formidable clinical challenge. Surgical excision in conjunction with radiation therapy may decrease the chance of keloid recurrence. Split-thickness skin grafts, however, are more prone to failure in the setting of radiation. In this report, we present a patient with a recurrent auricular keloid who underwent excision and immediate Integra (Integra LifeSciences, Plainsboro, NJ) application, followed by high–dose rate brachytherapy and interval split-thickness skin graft placement. A 23-year-old woman with a history of a recurrent auricular keloid after previous surgical excision, corticosteroid injection, and radiation underwent reexcision of her keloid. Integra was used to cover the resultant exposed auricular perichondrium. The patient then received high–dose rate brachytherapy (1500 cGy) on postoperative days 1 and 2, followed by definitive split-thickness skin graft placement 3 weeks after her initial surgery. The patient recovered from all interventions without complication. There was no evidence of keloid formation 27 months after the interval split-thickness skin graft placement at either the auricular recipient or thigh donor sites. We report the first case of a 2-stage reconstruction of a recurrent auricular keloid (composed of keloid excision and placement of Integra in conjunction with high–dose rate brachytherapy, followed by interval split-thickness skin grafting), resulting in an acceptable cosmetic result without evidence of recurrence at long-term follow-up.

An interdisciplinary approach to the prevention and treatment of groin wound complications after lower extremity revascularization.

BACKGROUND If not effectively treated, groin wound infections following lower extremity revascularization (LER) may result in graft or limb loss. METHODS A retrospective review was performed of all patients who underwent muscle flap transposition by a single surgeon after LER between 2006 and 2010. RESULTS Twenty-nine muscle transposition flaps were performed in 24 patients (21 sartorius, 6 rectus femoris, and 2 gracilis). Nineteen were for treatment of groin wound infections, two for treatment of lymphocele, one for coverage of exposed graft in the setting of pyoderma gangrenosum, and seven for infection prophylaxis. Two graft losses followed flap placement. The limb loss rate was 4%. When performed for therapeutic purposes, graft salvage rates were 100% for autogenous and 92% for synthetic grafts. CONCLUSIONS Muscle transposition flaps are an effective means of graft salvage in the setting of groin wound complications following LER and should be considered for infection prophylaxis in high-risk patients.

Body contouring after bariatric surgery: how much is really being done?

Abstract The proportion of postbariatric surgery patients who undergo body contouring (BC) procedures is unknown. We designed a study to explore demographic features and patient education regarding BC in the bariatric surgery (BS) population. A survey was mailed to 1158 patients who underwent BS by 2 surgeons between 2003 and 2011. A total of 284 (24.5%) patients responded. Seventy-two patients (25.4%) reported discussing BC surgery with their bariatric surgeon perioperatively. Forty patients (14.1%) were referred for plastic surgery consultation. Thirty-three patients (11.6%) underwent BC procedures. The most frequent reasons cited for not undergoing BC were expense (29.2%) and lack of awareness regarding options (23.6%). Thirty-nine percent of respondents reported that they might have chosen differently, had they received more information. As a result of insufficient perioperative counseling, the majority of BS patients are unaware of the multitude of BC procedures available. Additional efforts toward improving patient (and surgeon) education regarding postbariatric BC options are warranted.

Sequential second free fibula flap for the reconstruction of metachronous osteoradionecrosis of the mandible.

AbstractOsteoradionecrosis (ORN) of the mandible is a potentially catastrophic complication of external beam radiation therapy for head and neck malignancies. A 55-year-old man treated with chemoradiation for base-of-tongue cancer presented with a necrotic left mandibular body and underwent left mandibulectomy with right free fibula osteocutaneous flap reconstruction. Two and a half years later, he presented with right mandibular body ORN and underwent a second mandibular resection and subsequent reconstruction with a left fibula osteocutaneous free flap fixed in the midline to the previously placed contralateral fibula. He recovered well from all procedures. To the best of our knowledge, we report the first case of a patient with metachronous ORN of the mandible requiring resection and subsequent reconstruction with sequential free fibula flaps. Even in the presence of prior microvascular reconstructions, patients can successfully undergo additional reconstructive procedures to restore their function, appearance, and quality of life.

Optimization of Vasculogenesis within Naturally-Derived, Biodegradable Hybrid Hydrogel Scaffolds

IntroductIon: Cellular ingrowth and neovascularization of acellular tissue-regeneration scaffolds represent the ratelimiting steps of permanent integration.1 In previous work, we have demonstrated that naturally-derived, biodegradable hybrid hydrogel scaffolds fabricated from a 10:1 w/w combination of alginate and type I collagen allow for maximal human umbilical vein endothelial cell (HUVEC) adherence and invasion in an in vitro wound healing model. We next sought to stimulate endothelial tubule formation within these scaffolds.