Chris A. Campbell

Effects of perivascular Botulinum Toxin-A application on vascular smooth muscle and flap viability in the rat.

Botulinum toxin-A (BTX) has become a widely used pharmacologic agent for esthetic surgeons and those who treat neuromuscular and gastrointestinal conditions. Until recently, there has been very little basic science research related to how this powerful agent may be useful when applied to vessels. The mechanism of action of this agent suggests that it may be useful in treating vasospastic conditions and ischemic tissues. We present data from experiments conducted to establish whether perivascular application of BTX decreases skin flap necrosis in an island pedicle skin flap in the rat. Using an ischemic ventral pedicled island cutaneous flap model, 30 adult Sprague-Dawley rats were divided into groups and treated with BTX, papaverine, or saline to the intact vascular pedicle to determine the percentage of tissue necrosis and ischemia. Flaps were elevated, and the pedicle treated with 1 of the 3 agents, and the flaps reinset. Analysis of the percentage of flap necrosis and areas of flap ischemia were evaluated on postoperative day 4. There were no differences in area of flap necrosis between BTX-, papaverine-, and saline-treated animal groups. There was a significant decrease in flap ischemia in the papaverine-treated group compared with both BTX and saline (P < 0.01). When necrotic and ischemic areas were combined, papaverine again showed a protective effect when compared with the BTX- and saline-treated groups (P < 0.04). In our ischemic pedicled island cutaneous flap model, papaverine showed the greatest protective effect against skin flap ischemia compared with BTX and saline. However, our data suggest that BTX may provide a protective effect after the first several days following flap elevation.

Reducing Infectious Complications in Implant Based Breast Reconstruction: Impact of Early Expansion and Prolonged Drain Use.

IntroductionThe most common modality of breast reconstruction continues to be implant based, with infection being the most significant complication. Risk factors including radiation, obesity, and smoking have been associated with infection and other surgical complications. We hypothesized that prolonged drain use may likewise be associated with postoperative complications, particularly infection, and that early postoperative expansion may allow for earlier drain removal and improved outcomes. MethodsA retrospective chart review was performed to identify all immediate, tissue expander–based breast reconstruction patients using acellular dermal matrix. Time to first expansion, postoperative day (POD) of drain removal, and complication data including infection, seroma, wound separation, and skin necrosis were collected. Early expansion was defined as occurring before POD14, and prolonged drain duration as removal after POD21. Logistic regression was used to identify risk factors for complications. Fisher’s exact test was used to compare complications between early and late drain removal and early and late expansion. Spearman correlation was used to define the relationship of early expansion and drain duration. ResultsThree hundred twenty-three breast reconstructions met inclusion criteria. Our overall infection rate was 11.8%, seroma was 2.2%, skin necrosis 1.9%, and wound separation 4.3%. Logistic regression revealed prolonged drain use as an independent risk factor for infection (odds ratio, 3.3; P = 0.002). Earlier expansion was correlated with earlier post operative drain removal (r = 0.3, P = 0.001) with fewer early expansion patients (7.4%) requiring prolonged drain use than those undergoing late expansion (24.7%). Smoking was also associated with skin flap necrosis (odds ratio, 8.0; P = 0.002). ConclusionsProlonged drain use was associated with postoperative infection and may represent an independent source of infection or may be an indicator of delayed healing. Early tissue expansion was associated with earlier drain removal and so may help avoid infectious complications and improve outcomes. Early expansion was not associated with an increase in complications. Results from this study have informed our current drain management practice. Whether this has led to a reduction in our infection rate is a future topic of study.

Adipocytes constitutively release factors that accelerate keratinocyte proliferation in vitro

Keratinocytes grown directly on adipose tissue have greater proliferation rates than keratinocytes grown alone. It is unknown if factors released by adipose tissue into culture media could increase keratinocyte proliferation without requiring incorporation of adipose tissue into skin graft models, or serve as a substitute for the fibroblast feeder layer. Human keratinocytes were grown with and without NIH 3T3 fibroblast feeder layer in the following conditions (12 cultures per group) adipose tissue coculture (AT), cultures supplemented with medium from whole adipose tissue referred to as adipose-conditioned medium (ACM), and control. Proliferation was measured with a colorimetric proliferation assay and digital calculations of percent confluence over time. Culture morphology was assessed by light microscopy. ACM cultures without 3T3s, AT cultures with and without 3T3s, and 3T3 control cultures demonstrated a similarly significant keratinocyte proliferation increase over non-3T3 control (P < 0.05) corresponding with a 2-fold increase in percent confluence by day 7. ACM cultures with 3T3s proliferated significantly faster than all other treatment groups (P < 0.05) resulting in complete confluence by day 5. ACM cultures with and without 3T3s produced a thick keratinized layer by day 7 whereas all other cultures including AT cultures did not. Engineered tissue replacement can be accelerated and simplified by ACM without requiring the addition of adipose tissue or a fibroblast feeder layer to keratinocyte culture systems. ACM supplementation provides an additive proliferation benefit when combined with a feeder layer producing mature grafts in approximately half the time as keratinocytes alone by accelerating proliferation and increasing keratinization.

Complications of rigid internal fixation.

Over the past 20 years, there have been many advances in the development of bone fixation systems used in the practice of craniomaxillofacial surgery. As surgical practices have evolved, the complications of each technologic advance have changed accordingly. Interfragmentary instability of interosseous wiring has been replaced by the risk of exposure, infection, and palpability of plate and screw fixation systems. The improved rigidity of plate fixation requires anatomic alignment of fracture fragments. Failure to obtain proper alignment has led to the phenomenon known as “open internal fixation” of fracture fragments without proper reduction. The size of the plates has decreased to minimize palpability and exposure. However limitations in their application have been encountered due to the physiologic forces of the muscles of mastication and bone healing. In the pediatric population, the long-standing presence of plates in the cranial vault resulted in reports of transcranial migration and growth restriction. These findings led to the development of resorbable plating systems, which are associated with self-limited plate palpability and soft tissue inflammatory reactions. Any rigid system including these produces growth restriction in varying amounts. In this discussion, we review the reported complication rates of miniplating and microplating systems as well as absorptive plating systems in elective and traumatic craniofacial surgery.

Postoperative outcomes and reliability of “sensation-sparing” sural nerve biopsy

Sural nerve biopsy is a valuable tool for the diagnosis of neuropathic disorders. However, concerns of persisting pain and numbness resulting from traditional whole sural nerve biopsy have led to interfascicular dissection techniques with inconsistent benefits over whole nerve biopsy. In this study we describe a novel technique of atraumatic anterior fascicular sural nerve biopsy designed to preserve calcaneal sensation while maintaining diagnostic benefit, without requiring significant interfascicular dissection. A 10‐year chart review was conducted to identify patients who underwent anterior fascicular sural nerve biopsy. Pathology reports were reviewed to confirm specimen adequacy, and clinical notes were reviewed to determine if a diagnosis was rendered. Retrospective questionnaires were conducted to evaluate perioperative and long‐term sequelae and patient satisfaction. The proportion of patients with symptoms involving the heel versus the dorsolateral foot was evaluated with Fishers exact test. Specimens from all 53 patients were acceptable and permitted a diagnosis. Twenty‐two patients completed the retrospective survey with an average follow‐up of 5 years (1.2–11.4 years). Eight patients (34%) experienced numbness of the dorsolateral foot, and 1 patient (4.5%) reported numbness of the lateral heel that lasted >6 months (P = 0.001). Persistent dorsolateral foot pain and cold sensitivity were reported by 5 patients (22.7%), but no patients reported lateral heel symptoms (P = 0.04). Symptoms were noted by patients most commonly while standing or walking, but they did not result in functional impairment in any case. Atraumatic anterior fascicular sural nerve biopsy predictably preserved essential lateral heel sensation in patients with neuropathic disorders while providing diagnostic utility. Muscle Nerve 40: 603–609, 2009

Burn management in sub-Saharan Africa: opportunities for implementation of dedicated training and development of specialty centers.

BACKGROUND In low- and middle-income countries burn injuries remain responsible for a large burden of death and disability. Given an annual worldwide incidence of almost 11 million new individuals affected per year, major burn injuries have a higher annual incidence than HIV and tuberculosis combined. METHODS A survey instrument was adapted for use as an international assessment tool and then used to measure the availability of personnel, materials, equipment, medicines, and facility resources in nine Rwandan hospitals, including three referral centers. RESULTS Forty-four percent of surveyed hospitals had a dedicated acute-care burn ward, while two-thirds had intensive care options. Relevant wound-care supplies were widely available, but gaps in the availability of critical pieces of equipment such as monitors, ventilators, infusion pumps, electrocautery, and dermatomes were discovered in many of the surveyed institutions, including referral hospitals. Early excision and grafting were not performed in any of the hospitals and there were no physicians with specialty training in burn care. CONCLUSIONS Whereas all surveyed hospitals were theoretically equipped to handle the initial resuscitation of burn patients, none of the hospitals were capable of delivering comprehensive care due to gaps in equipment, personnel, protocols, and training. Accordingly, steps to improve capacity to care for those with thermal injury should include training of physicians specialized in critical care and trauma surgery, as well as plastic and reconstructive surgery. Consideration should be given to creation of national referral centers specializing in burn care.

Options for Closure of the Infected Abdomen

BACKGROUND The infected abdomen poses substantial challenges to surgeons, and often, both temporary and definitive closure techniques are required. We reviewed the options available to close the abdominal wall defect encountered frequently during and after the management of complicated intra-abdominal infections. METHODS A comprehensive review was performed of the techniques and literature on abdominal closure in the setting of intra-abdominal infection. RESULTS Temporary abdominal closure options include the Wittmann Patch, Bogota bag, vacuum-assisted closure (VAC), the AbThera™ device, and synthetic or biologic mesh. Definitive reconstruction has been described with mesh, components separation, and autologous tissue transfer. CONCLUSION Reconstructing the infected abdomen, both temporarily and definitively, can be accomplished with various techniques, each of which is associated with unique advantages and disadvantages. Appropriate judgment is required to optimize surgical outcomes in these complex cases.

Macrophage Recruitment and Polarization During Collateral Vessel Remodeling in Murine Adipose Tissue

During autologous flap transplantation for reconstructive surgeries, plastic surgeons use a surgical pre‐treatment strategy called “flap delay,” which entails ligating a feeding artery into an adipose tissue flap 10–14 days prior to transfer. It is believed that this blood flow alteration leads to vascular remodeling in the flap, resulting in better flap survival following transfer; however, the structural changes in the microvascular network are poorly understood. Here, we evaluate microvascular adaptations within adipose tissue in a murine model of flap delay.

An Algorithmic Anatomical Subunit Approach to Pelvic Wound Reconstruction.

Background: Prior radiation therapy, pelvic dead space, and a dependent location contribute to perineal dehiscence rates as high as 66 percent after primary closure of pelvic wounds. Various regional flaps have been described to reconstruct pelvic defects, but an algorithmic pairing of individual flaps to specific anatomical regions has not been described. Methods: A retrospective review of a prospectively maintained database was performed to identify consecutive pelvic reconstructions from 2010 to 2013 with at least 6 months’ follow-up. Pelvic defects and resulting flaps were described by anatomical subunits involved: anterolateral thigh flap for mons, gracilis flap for labia majora and introitus, vertical rectus abdominis myocutaneous flap for vagina and/or perineal raphe, and gluteus musculocutaneous flap for isolated perianal defects. Results: Twenty-seven women and three men underwent consecutive pelvic reconstruction with a mean age of 60 years (range, 26 to 83 years) and a mean body mass index of 28 kg/m2 (range, 17 to 40 kg/m2). Twenty-one patients (70 percent) had prior radiation therapy. In total, 45 flaps were performed according to the subunit principle. Three patients had a minor dehiscence (<5 cm), one patient had a major dehiscence, and one required reoperation for abscess. There were two partial flap losses necessitating débridement and readvancement of the flap. Twenty-five percent of female patients were sexually active after vaginal reconstruction. Conclusions: The pelvic subunit principle provides an effective algorithm for choosing the ideal pedicled flap for each region involved in acquired pelvic defects. This algorithm is based on individual attributes that make each flap most appropriate for each subunit. Complications were minimal and patient satisfaction with appearance and function was excellent.

The effect of local Rho-kinase inhibition on murine wound healing

IntroductionThe process of cutaneous wound healing and contraction is a complex orchestra of temporally and spatially controlled signaling moieties and pathways. Rho-kinase (ROCK) has been implicated as a key downstream effector of transforming growth factor &bgr;1 (TGF-&bgr;1) signal transduction, which ultimately coordinates &agr;-smooth muscle actin (&agr;-SMA)–mediated wound contraction. Previous in vitro studies of ROCK inhibition have demonstrated decreased fibroblast contraction and epithelial advancement after wounding. In vivo systemic ROCK inhibition revealed modest late wound healing attenuation in contrast to &agr;-SMA knock-out rodents. The goal of this investigation was to explore the effect of local delivery of a ROCK inhibitor on an in vivo murine model of wound healing. MethodsFull-thickness cutaneous wounds were created in 24 white mice and were treated daily with local topical delivery of 100 &mgr;L of 10−4 M ROCK inhibitor (Y27632) or saline control. Percent wound surface area over time and compensatory epithelial advancement was quantified. After 12 days, tissue was harvested for assessment of inflammatory cellular density, immunohistochemistry for &agr;-SMA, and TGF-&bgr; protein expression. ResultsWounds subjected to local ROCK inhibition were significantly larger than controls at early time points, and this effect of delayed wound contraction in ROCK-inhibited wounds persisted for 7 days after wounding (P < 0.05). The effect of ROCK inhibition on delay of wound contraction was normalized at day 12. There was no significant difference between control and ROCK-inhibited groups in the area of the nascent epithelium beyond the wound margin, wound inflammatory cellular density, and TGF-&bgr;1 expression. However, ROCK inhibition led to as statistically significant decrease in &agr;-SMA stress fiber formation compared to controls [32.5% (3.5%) vs 17.4% (2.6%); P < 0.05]. ConclusionsLocal delivery of a ROCK inhibitor delayed the time course of murine wound contraction in a manner similar to that previously reported in &agr;-SMA knock-out rodents, thus demonstrating an effective method for in vivo ROCK inhibition. Accordingly, &agr;-SMA stress fiber formation was inhibited in treated wound beds without altering local inflammation, TGF-&bgr;1 expression, or epithelial wound edge advancement.