Tissue oxygenation, anemia, and perfusion in relation to wound healing in surgical patients

An update review on risk factors and scales for prediction of deep sternal wound infections

Surgical site infections are the most common nosocomial infections in surgical patients. The preventable and the unmodifiable risk factors for deep sternal wound infections (DSWI) have been amply assessed in the literature. The aim of this review was to describe the results of the numerous published studies to describe all the DSWI risk factors and the scales devised to predict SWI, with a view to providing an update on this issue. A comprehensive search of the Medline and Embase databases was performed (considering studies from January 1995 to April 2011); and a manual search was also conducted using references cited in original publications and relevant review articles. There are several risk factors associated with DSWI, which could be classified in four categories as demographic (e.g. sex and age), behavioural (e.g. smoking and obesity), baseline clinical conditions (e.g. diabetes, hypertension and COPD) and surgical operative risk factors (e.g. duration of operation and emergency operation). Six scales for predicting the risk of DSWI are described in the literature: they vary not only in accuracy but also in ease of application and they are applied at different times (some only preoperatively and others also postoperatively). This study provides a broad update on our knowledge of the risk factors for DSWI and the scales for prediction with a view to improving the management of infections at cardiosurgery units.

Necrotizing enterocolitis and the role of anemia of prematurity

Necrotizing enterocolitis (NEC) is one of the most common surgical diseases of preterm infants, with significant short- and long-term morbidity and mortality. Although the etiology of NEC remains elusive, multiple factors adversely affecting the intestinal mucosal integrity of preterm infants are known to be associated with NEC. Anemia and red blood cell (RBC) transfusion-related gut injury have been shown to have strong correlation with NEC. Anemia potentially compromises mucosal integrity with subsequent poor healing, and this injury may be augmented by yet unknown factors associated with RBC transfusions. Although convincing evidence is lacking, there is a need for guidelines to keep the hematocrit within clinically and physiologically relevant limits by appropriate interventions. Further investigations need to focus on assessing the interplay between anemia, chronically hypoxemic/hypoperfused intestines, and early iron therapy or other pharmacologic approaches for prevention/treatment of anemia and RBC transfusions.

Comparison of bacteria and fungus-binding mesh, foam and gauze as fillers in negative pressure wound therapy--pressure transduction, wound edge contraction, microvascular blood flow and fluid retention

Bacteria- and fungus-binding mesh binds with and inactivates bacteria and fungus, which makes it an interesting alternative, wound filler for negative pressure wound therapy (NPWT). This study was conducted to compare the performance of pathogen-binding mesh, foam and gauze as wound fillers in NPWT with regard to pressure transduction, fluid retention, wound contraction and microvascular blood flow. Wounds on the backs of 16 pigs were filled with pathogen-binding mesh, foam or gauze and treated with NPWT. The immediate effects of 0, -40, -60, -80 and -120 mmHg, on pressure transduction and blood flow were examined in eight pigs using laser Doppler velocimetry. Wound contraction and fluid retention were studied during 72 hours of NPWT at -80 and -120 mmHg in the other eight pigs. Pathogen-binding mesh, gauze and foam provide similar pressure transduction to the wound bed during NPWT. Blood flow was found to decrease 0.5 cm laterally from the wound edge and increase 2.5 cm from the wound edge, but was unaltered 5.0 cm from the wound edge. The increase in blood flow was similar with all wound fillers. The decrease in blood flow was more pronounced with foam than with gauze and pathogen-binding mesh. Similarly, wound contraction was more pronounced with foam, than with gauze and pathogen-binding mesh. Wound fluid retention was the same in foam and pathogen-binding mesh, while more fluid was retained in the wound when using gauze. The blood flow 0.5-5 cm from the wound edge and the contraction of the wound during NPWT were similar when using pathogen-binding mesh and gauze. Wound fluid was efficiently removed when using pathogen-binding mesh, which may explain previous findings that granulation tissue formation is more rapid under pathogen-binding mesh than under gauze. This, in combination with its pathogen-binding properties, makes this mesh an interesting wound filler for use in NPWT.

The impact of heavy smoking on anastomotic leakage and stricture after low anterior resection in rectal cancer patients

BACKGROUND

Anastomotic complications after low anterior resection are associated with perianastomotic ischemia. Smoking is one of the main causes of microvascular disease that is correlated with tissue ischemia. The purpose of the present study was to assess the impact of smoking on anastomotic complications after low anterior resection in rectal cancer patients.

METHODS

Between January 2005 and December 2008, 412 patients underwent low anterior resection for rectal cancers by a single surgeon at Seoul National University Hospital. Excluded from this series were 197 patients with postoperative radiation therapy, cancers that were located above 10 cm from the anal verge, or lack of medical records, and the remaining 215 patients were included for analysis. Significant variables in the univariate analysis were subsequently subject to multivariate analysis for identification of risk factors for complications.

RESULTS

The rate of anastomotic complications was 10.7% (23 of 215 patients). Univariate analysis showed that male gender, body mass index higher than 25 kg/m(2), smoking history, smoking amount, type of operation, and presence of a protective stoma were associated with anastomotic complications. In multivariate analysis, a history of heavy smoking was a significant risk factor for anastomotic complications.

CONCLUSIONS

A history of heavy smoking (more than 40 pack-years) is an independently significant risk factor for anastomotic complications after low anterior resection in rectal cancer patients.

A brief relaxation intervention reduces stress and improves surgical wound healing response: a randomised trial

Psychological stress has been shown to impair wound healing, but experimental research in surgical patients is lacking. This study investigated whether a brief psychological intervention could reduce stress and improve wound healing in surgical patients. This randomised controlled trial was conducted at a surgical centre. Inclusion criteria were English-speaking patients over 18 years booked to undergo elective laparoscopic cholecystectomy; exclusion criteria were cancellation of surgery, medical complications, and refusal of consent. Seventy five patients were randomised and 15 patients were excluded; 60 patients completed the study (15 male, 45 female). Participants were randomised to receive standard care or standard care plus a 45-min psychological intervention that included relaxation and guided imagery with take-home relaxation CDs for listening to for 3 days before and 7 days after surgery. In both groups ePTFE tubes were inserted during surgery and removed at 7 days after surgery and analysed for hydroxyproline as a measure of collagen deposition and wound healing. Change in perceived stress from before surgery to 7-day follow-up was assessed using questionnaires. Intervention group patients showed a reduction in perceived stress compared with the control group, controlling for age. Patients in the intervention group had higher hydroxyproline deposition in the wound than did control group patients (difference in means 0.35, 95% CI 0.66-0.03; t(43)=2.23, p=0.03). Changes in perceived stress were not associated with hydroxyproline deposition. A brief relaxation intervention prior to surgery can reduce stress and improve the wound healing response in surgical patients. The intervention may have particular clinical application for those at risk of poor healing following surgery.

Wound healing problems in total knee arthroplasty

It is important to avoid underestimating the significance of wound complications following total knee arthroplasty (TKA). Expedient and aggressive care is recommended. Understanding the blood supply to the skin around the knee and measures to prevent wound complications are fundamental to preventing wound problems. A detailed patient history and physical examination will identify high-risk patients and any modifiable risk factors. Operative techniques such as raising full-thickness skin flaps and judicious placement of skin incisions in the presence of pre-existing scars can greatly reduce the incidence of wound problems. The first step in treating wound problems is recognizing when a problem is present and knowing when a minor problem can turn into a major one. Superficial infections or stitch abscesses can be treated with conservative treatment. However, the surgeon should have a low threshold to revert to surgical management if drainage persists. Skin necrosis or non-viable skin must be excised in the operating room, and the presence of a deep infection must be diagnosed by joint aspiration. The appropriate course of action in dealing with deep infection is dependent on the duration elapsed since the index procedure. The ability to perform a medial gastrocnemius muscle flap and skin graft is an invaluable skill in complex cases where primary wound closure cannot be achieved. Meticulous attention to detail during surgery and aggressive surgical treatment of wound complications can be the difference in saving the knee.

Evaluation of skin graft take following post-burn raw area in normovolaemic anaemia

Background:

Traditional wisdom is that wound healing is directly related to haemoglobin level in the blood; therefore blood transfusion is given in anaemic patients to raise the haemoglobin level for better wound healing.

Methods:

Evaluation of wound healing in the form of split thickness skin graft take was done in 35 normovolaemic anaemic patients (haemoglobin level of < 10 gm/ dl) and compared with control group (patients with haemoglobin level of 10 or > 10 gm/ dl).

Results:

There was no statistically significant difference in mean graft take between the two groups.

Conclusion:

It is not mandatory to keep haemoglobin level at or >10 g/dL or PCV value at or >30% for skin graft take, as mild to moderate anaemia per se does not cause any deleterious effect on wound healing; provided perfusion is maintained by adequate circulatory volume. Prophylactic transfusion to increase the oxygen carrying capacity of the blood for the purpose of wound healing is not indicated in asymptomatic normovolemic anaemic patients (with haemoglobin levels greater than 6g/dL) without significant cardiovascular or pulmonary disease.

Effect of WF10 (immunokine) on diabetic foot ulcer therapy: a double-blind, randomized, placebo-controlled trial

This randomized controlled trial was undertaken to evaluate the effect of WF10 (Immunokine) as an adjunct to the standard treatment of diabetic foot ulcer. A total of 40 participants were randomized into 2 groups of 20. One group underwent standard therapy combined with infusions of WF10, and 1 underwent standard therapy combined with placebo. The wound severity scores, which vary with the severity of infection and inflammation, necrotic and granulation tissues, and wound depth and area, were assessed weekly for 9 weeks. Before treatment, the wound severity scores were not significantly different statistically between the 2 groups (13.7 ± 2.8 and 12.9 ± 3.2). After 9 weeks, the WF10 group had a statistically significant decreased wound severity score compared with that of the placebo group (1.8 ± 1.9 versus 4.4 ± 5.3, respectively, p < .05). Subgroup analyses comparing the WF10 and placebo groups showed statistically significant decreases of infection and inflammation (0.0 ± 0.0 versus 0.8 ± 0.9, respectively, p < .01), necrotic tissue (0.0 ± 0.0 versus 0.8 ± 1.1, respectively, p < .01), and an increase of the amount of granulation tissue (0.1 ± 0.3 versus 0.8 ± 1.2, respectively, p < .05). The wound depth and wound area also decreased more in the WF10 group; however, these decreases were not statistically significant. No severe adverse events were observed throughout the observation period. We concluded that the addition of WF10 to standard wound care statistically significantly reduced the wound severity score, infection and inflammation, and necrotic tissue and enhanced the formation of granulation tissue.

Haemodynamic goal-directed therapy and postoperative infections: earlier is better. A systematic review and meta-analysis

Introduction

Infectious complications are the main causes of postoperative morbidity. The early timing of their promoting factors is the rationale for perioperative strategies attempting to reduce them. Our aim was to determine the effects of perioperative haemodynamic goal-directed therapy on postoperative infection rates.

Methods

We performed a systematic review and meta-analysis. MEDLINE, EMBASE, The Cochrane Library and the DARE databases were searched up to March 2011. Randomised, controlled trials of major surgery in adult patients managed with perioperative goal-directed therapy or according to routine haemodynamic practice were included. Primary outcome measure was specific type of infection.

Results

Twenty-six randomised, controlled trials with a combined total of 4,188 participants met our inclusion criteria. Perioperative goal-directed therapy significantly reduced surgical site infections (pooled OR 0.58, 95% CI 0.46 to 0.74; P < 0.0001), pneumonia (pooled OR 0.71, 95% CI 0.55 to 0.92; P = 0.009), and urinary tract infections (pooled OR 0.44, 95% CI 0.22 to 0.84; P = 0.02). A significant benefit was found regarding total infectious episodes (OR 0.40, 95% CI 0.28 to 0.58; P < 0.00001).

Conclusions

Flow-directed haemodynamic therapy designed to optimise oxygen delivery protects surgical patients against postoperative hospital-acquired infections and must be strongly encouraged, particularly in the high-risk surgical population.

Treatment of ankle fractures in patients with diabetes

Patients with diabetes mellitus have a higher risk of complications after sustaining an ankle fracture, including fracture displacement, superficial and deep infection, hardware failure, and neuropathic arthropathy. With the increased incidence of diabetes among the aged, the increased incidence of complications due to diabetes mellitus and its sequelae are important to keep in mind when treating ankle fractures.

Low flow oxygenation of full-excisional skin wounds on diabetic mice improves wound healing by accelerating wound closure and reepithelialization

Oxygen-based therapies have proven effective in treating chronic and difficult-to-heal skin wounds, but the current therapeutic approaches suffer from major limitations and they do not allow for continuous wound treatment. Here we examined whether the continuous treatment of wounds with pure oxygen at low flow rates accelerates wound closure and improves wound healing in a murine model of diabetic skin wounds. Two full-excisional dorsal skin wounds were generated on 15-week-old diabetic db/db mice and treated for 10 weeks continuously with pure oxygen (>99·9%) at low flow rates (3 ml/h). After 6 days, oxygen treatment resulted in a mean reduction of the original wound size by 60·2% as compared with only 45·2% in wounds on control mice that did not receive pure oxygen.(P = 0·022). After 10 days, oxygen-treated wounds were 83·1% closed compared with 71·2% in wounds on control mice. While reepithelialisation was complete after 10 days in over 57% of wounds receiving low flow oxygen treatment, significant epithelial gaps remained in 75% wounds from mice that did not receive oxygen. Continuous low flow oxygenation significantly improves healing of diabetic skin wounds in mice and may therefore be an effective treatment for chronic cutaneous and possibly other slow-healing wounds in diabetic patients.

Effects of sevoflurane on collagen production and growth factor expression in rats with an excision wound

BACKGROUND

Sevoflurane is a widely used inhalation anesthetic, but there are no studies on its effect on the wound-healing process. This study was undertaken to evaluate the effect of exposure time to sevoflurane on wound healing.

METHOD

Male Sprague-Dawley rats were used. Two circular full-thickness skin defects 8 mm in diameter were made on the dorsum of the rats. The animals were divided into six groups according to exposed gas type and time: S1 (sevoflurane, 1 h), S4 (sevoflurane, 4 h), S8 (sevoflurane, 8 h), O1 (oxygen, 1 h), O4 (oxygen, 4 h), and O8 (oxygen, 8 h). The surface area of the wounds was measured 0, 1, 3, and 7 days after surgery. Separately, the mean blood pressures (MBP) and arterial oxygen pressures (PaO(2)) were monitored during the sevoflurane exposure. Collagen type I production and transforming growth factor-beta1 (TGF-beta1) and basic fibroblast growth factor (bFGF) expression on the wound surface were analyzed. Routine histological analysis was also performed.

RESULT

Exposure duration to sevoflurane had no influence on MBP and PaO(2). The reduction in wound size and collagen type I production was delayed in S8. The expression of TGF-beta1 and bFGF on the wound surface in S8 was significantly attenuated in S8. The histology of the S8 demonstrated a delayed healing status.

CONCLUSIONS

Prolonged exposure to sevoflurane might alter the inflammatory phase of the wound-healing process by attenuation of growth factor expression such as TGF-beta1 and bFGF and subsequently by reduced collagen production.

Temperature control and the role of supplemental oxygen

Unrecognized and untreated intraoperative hypothermia remains a common avoidable scenario in the modern operating room. Failure to properly address this seemingly small aspect of the total operative care has been shown to have profound negative patient consequences including increased incidence of postoperative discomfort, surgical bleeding, requirement of allogenic blood transfusion, wound infections, and morbid cardiac events. All of these ultimately lead to longer hospitalizations and higher mortality. To avoid such problems, simple methods can be employed by the surgeon, anesthesiologist, and ancillary personnel to ensure euthermia. Similarly, another effortless method to potentially improve surgical outcomes is the liberal use of supplemental oxygen. Promising preliminary data suggests that high-concentration oxygen during and after surgery may decrease the rate of surgical site infections and gastrointestinal anastomotic failure. The precise role of supplemental oxygen in the perioperative period represents an exciting area of potential research that awaits further validation and analysis. In this article, the authors explore the data regarding both temperature regulation and supplemental oxygen use in an attempt to define further their emerging role in the perioperative care of patients undergoing colorectal surgery.

Atypical calciphylaxis in a patient receiving warfarin then resolving with cessation of warfarin and application of hyperbaric oxygen therapy

Calciphylaxis is a rare, usually fatal vasculopathic disorder characterized by cutaneous ischemia and necrosis due to calcification of arterioles. Although calciphylaxis is most frequently associated with end-stage renal disease (ESRD) and secondary hyperparathyroidism, it has been reported infrequently among patients on warfarin. No standard treatment has been established for atypical calciphylaxis; however, a potentially beneficial treatment is hyperbaric oxygen therapy (HBOT). A high degree of clinical suspicion, early diagnosis, and understanding the pathophysiology of this disease promotes the optimal management of this extremely morbid and often fatal condition.

CASE REPORT

We present a 63-year-old Polynesian woman with biopsy-proven calciphylaxis in the absence of ESRD or elevated serum calcium levels while taking warfarin. Therapeutic dose enoxaparin was substituted for warfarin and she received 40 sessions of HBOT during which lower extremity ulcers resolved.

DISCUSSION

Warfarin has been implicated when calciphylaxis presents in an atypical fashion. No guidelines exist for treatment of atypical calciphylaxis in the setting of concomitant warfarin therapy. Up to 80% of calciphylaxis patients die within 1 year of diagnosis. Our patient was changed to low-molecular-weight heparin and received HBOT.

CONCLUSION

We present what we believe is the first case of atypical calciphylaxis thought to be attributable to warfarin treated with a therapeutic substitution of anticoagulant and HBOT leading to resolution of cutaneous lesions.

Sutures versus staples for skin closure in orthopaedic surgery: meta-analysis

OBJECTIVE

To compare the clinical outcomes of staples versus sutures in wound closure after orthopaedic surgery.

DESIGN

Meta-analysis.

DATA SOURCES

Medline, CINAHL, AMED, Embase, Scopus, and the Cochrane Library databases were searched, in addition to the grey literature, in all languages from 1950 to September 2009. Additional studies were identified from cited references. Selection criteria Two authors independently assessed papers for eligibility. Included studies were randomised and non-randomised controlled trials that compared the use of staples with suture material for wound closure after orthopaedic surgery procedures. All studies were included, and publications were not excluded because of poor methodological quality. Review methods Two authors independently reviewed studies for methodological quality and extracted data from each paper. Final data for analysis were collated through consensus. The primary outcome measure was the assessment of superficial wound infection after wound closure with staples compared with sutures. Relative risk and mean difference with 95% confidence intervals were calculated and pooled with a random effects model. Heterogeneity was assessed with I(2) and chi(2) statistical test.

RESULTS

Six papers, which included 683 wounds, were identified; 332 patients underwent suture closure and 351 staple closure. The risk of developing a superficial wound infection after orthopaedic procedures was over three times greater after staple closure than suture closure (relative risk 3.83, 95% confidence interval 1.38 to 10.68; P=0.01). On subgroup analysis of hip surgery alone, the risk of developing a wound infection was four times greater after staple closure than suture closure (4.79, 1.24 to 18.47; P=0.02). There was no significant difference between sutures and staples in the development of inflammation, discharge, dehiscence, necrosis, and allergic reaction. The included studies had several major methodological limitations, including the recruitment of small, underpowered cohorts, poorly randomising patients, and not blinding assessors to the allocated methods of wound closure. Only one study had acceptable methodological quality.

CONCLUSIONS

After orthopaedic surgery, there is a significantly higher risk of developing a wound infection when the wound is closed with staples rather than sutures. This risk is specifically greater in patients who undergo hip surgery. The use of staples for closing hip or knee surgery wounds after orthopaedic procedures cannot be recommended, though the evidence comes from studies with substantial methodological limitations. Though we advise orthopaedic surgeons to reconsider their use of staples for wound closure, definitive randomised trials are still needed to assess this research question.

Wound edge microvascular blood flow: effects of negative pressure wound therapy using gauze or polyurethane foam

The aim of this study was to examine the effects of negative pressure wound therapy (NPWT) on wound edge microvascular blood flow, comparing different wound fillers. Wounds were created on the backs of 7 pigs. NPWT was applied, using either foam or gauze, at -50,-75, -100, -125, -150, or -175 mm Hg. Microvascular blood flow was measured in muscle tissue, subcutaneous tissue, and in the wound bed, at 0.5, 1, and 2.5 cm from the wound edge, using laser Doppler velocimetry. Similar patterns of blood flow response were observed when using foam or gauze. At 2.5 cm from the wound edge there was an increase in microvascular blood flow, while blood flow was decreased closer (0.5 cm) to the wound edge. The blood flow effects were similar at the different levels of negative pressure in muscle tissue, subcutaneous tissue, and in the wound bed. Altered microvascular blood flow to the wound edge may be one of the mechanisms by which NPWT facilitates healing.

Effect of the combination of fibrin glue and growth hormone on intestinal anastomoses in a pig model of traumatic shock associated with peritonitis

BACKGROUND

Intra-abdominal sepsis and hemorrhagic shock have been found to impair the healing of intestinal anastomoses. The present study examined whether fibrin glue (FG) and recombinant human growth hormone (GH) can improve intestinal primary anastomotic healing in a pig model of traumatic shock associated with peritonitis. Further, the study was designed to investigate the probable mechanism of these agents.

METHODS

Female anesthetized pigs were divided into five groups. Group sham (n = 7), pigs without traumatic shock had small bowel resection anastomoses; group control (n = 14), pigs had bowel resection anastomoses 24 h after abdominal gunshot plus exsanguination/resuscitation; group FG (n = 14); group GH (n = 14); group FG/GH (n = 14), pigs received FG, recombinant GH, or both, respectively. Recombinant GH was given daily for 7 days. Blood samples were collected daily for measurement of interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha levels. Investigations also included adhesion formation, anastomotic bursting pressure, tensile strength, hydroxyproline (HP) content, myeloperoxidase (MPO), tumor necrosis factor (NF)-kappaB activity, and histology analysis 10 days later. A second experiment (n = 20 subjects assigned to each of the five groups) was designed to study survival during the first 20 postoperative days.

RESULTS

Traumatic shock associated with peritonitis led to significant decreases in intestinal anastomotic bursting pressures, tensile strengths, and tissue hydroxyproline content, along with severe adhesion formation, increases in MPO activity and NF-kappaB activity, and plasma levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6). Both FG and recombinant GH treatment led to early significant increases in plasma levels of TNF-alpha and IL-6. At the same time, FG alone, unlike recombinant GH alone, led to significant increases in anastomotic bursting pressures, tensile strength, and tissue HP content, along with decreases in anastomotic MPO and NF-kappaB activity and later plasma levels of TNF-a and IL-6. The FG group also developed more marked neoangiogenesis and collagen deposition on histology analysis. However, FG and recombinant GH synergistically effected improved anastomotic healing, abolishing the infaust effects promoted by recombinant GH. Adhesion formation after intestinal anastomosis could not be lowered by FG alone or by the combination of FG and recombinant GH. Both FG alone and FG/GH, in contrast to GH alone and control treatment, significantly prolonged the survival time of experimental animals.

CONCLUSIONS

We found that FG, but not recombinant GH, could lower the risk of anastomotic leakage, improve intestinal anastomotic healing, and prolong survival in a pig model of traumatic shock associated with peritonitis. Both FG and recombinant GH synergistically effected improved intestinal anastomotic healing. It was suggested that GH could be used locally to promote intestinal anastomotic healing in intra-abdominal peritonitis.

Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present.

Risk factors for anastomotic leakage following intersphincteric resection for very low rectal adenocarcinoma

BACKGROUND

The aim of this study was to perform a retrospective analysis of the risk factors for anastomotic leakage following intersphincteric resection (ISR) for very low rectal cancer.

METHODS

Between 1993 and 2007, 120 patients with T1-T3 rectal adenocarcinomas located 1 to 5 cm (median 3 cm) from the anal verge underwent ISR without radiotherapy. Univariate and multivariate analyses of 47 prospectively recorded parameters were conducted.

RESULTS

All patients had total mesorectal excision after complete bowel preparation. Of them, 103 underwent partial resection, and 17 underwent complete resection of the internal sphincter. Some 108 patients had a defunctioning stoma. Morbidity and mortality rates were 33% and 0.8%, respectively. Fifteen patients (13%) developed clinical leakage, and six (5%) had severe leakage causing relaparotomy, permanent stoma, or death. Univariate analysis of risk factors for clinical leakage revealed tumor annularity, intraoperative blood transfusion, and pulmonary disease to be significant. Multivariate analysis showed transfusion (hazard ratio, 6.5 [95% confidence interval, 1.4 to 30]; p = 0.018) and pulmonary disease (6.3 [1.6 to 26]; p = 0.009) to be independently significant. Moreover, transfusion (71 [3.0 to 1000]; p = 0.008), colonic J-pouch (32 [1.8 to 500]; p = 0.018), and pulmonary disease (32 [1.1 to 1000]; p = 0.044) were independently associated with severe leakage.

CONCLUSIONS

This study suggests intraoperative blood transfusion and pulmonary disease as independent risk factors for clinical and severe leakage following ISR and colonic J-pouch as that for severe leakage. By considering these factors, we may be able to stratify high-risk patients and prepare countermeasures.

Diabetic foot ulcers: effects of hyperoxia and SDF-1α on endothelial progenitor cells

Diabetes mellitus is a common disease afflicting many people. In addition to coronary artery disease, diabetic retinopathy and renal failure, diabetic patients face abnormal wound healing and have increased lower extremity ulcers and amputations. In diabetes, wound healing is altered due to both macrovascular and microvascular processes. While the former can be addressed with surgical intervention, the latter is more difficult to correct. Neovascularization within the granulation tissue via angiogenesis and vasculogenesis is critical for wound healing. Endothelial progenitor cells (EPCs) have been implicated in vasculogenesis. Mobilization of EPCs from the bone marrow is impaired in diabetes and homing of EPCs to the wound is also abnormal. Recent studies show that hyperoxia and administration of exogenous stromal-derived factor-1α increases circulatory and wound levels of EPCs and improves wound healing in diabetic mice. These findings have great potential for translation into human counterparts as the treatment for this prevalent disease matures.

Hernia repair: the search for ideal meshes

Background

Effective repair of hernia is a difficult task. There have been many advances in hernia repair techniques over the past 50 years, but new strategies must be considered to enhance the success of herniorrhaphy.

Discussion

At the 30th International Congress of the European Hernia Society, nine experts in hernia repair and experimental mesh evaluation participated in a roundtable discussion about today’s unmet needs in hernia repair, including what constitutes an “ideal” hernia repair and the portfolio of “ideal” mesh prostheses. Defining characteristics of lightweight mesh, mesh alternatives, the surgeon’s role in hernia repair, adverse events, the unmet requirements for today’s hernia repair, and optimized animal models were among the topics discussed.

Conclusion

The ideal mesh’s construction is still in progress, but greater understanding of its critical characteristics was explored. It is hoped that these suggestions will lead to the development of improved hernia treatments and a maximally effective portfolio of hernia mesh prostheses.

Randomized clinical trial of the effect of glucocorticoids on peritoneal inflammation and postoperative recovery after colectomy

Background

Recent data have suggested a relationship between postoperative fatigue and the peritoneal cytokine response after surgery. The aim of this study was to test the hypothesis that preoperative administration of glucocorticoids before surgery would decrease fatigue and enhance recovery, by reducing the peritoneal production of cytokines.

Methods

In a double-blind randomized controlled study, patients undergoing elective, open colonic resection were administered 8 mg dexamethasone or normal saline. Patients were treated within an enhanced recovery after surgery programme. Primary outcomes were cytokine levels in peritoneal drain fluid and fatigue as measured by the Identity–Consequence Fatigue Scale (ICFS).

Results

Baseline parameters were similar for 29 patients in the dexamethasone group and 31 in the placebo group. Patients who received dexamethasone had lower ICFS scores on days 3 and 7. Dexamethasone was associated with significantly lower peritoneal fluid interleukin (IL) 6 and IL-13 concentrations on day 1, and these correlated with changes in the ICFS score. There was no significant increase in adverse events in the dexamethasone group.

Conclusion

Preoperative administration of dexamethasone resulted in a significant reduction in early postoperative fatigue, associated with an attenuated early peritoneal cytokine response. Peritoneal production of cytokines may therefore be important in postoperative recovery. Registration number: ACTRN12607000066482 (http://www.anzctr.org.au/).

Evidence-based recommendations for the use of topical oxygen therapy in the treatment of lower extremity wounds

Topical oxygen therapy provides another tool in the armamentarium of clinicians treating refractory lower extremity wounds. Devices suitable for providing topical oxygen therapy in a clinical setting have recently become available. This article reviews the evidence to justify the use of this treatment modality, including in vitro, preclinical data, and clinical data. It also provides a protocol for how to administer topical oxygen therapy as well as guidance on patient selection and management to optimize outcomes. Randomized controlled trials are not yet reported and clearly necessary. The current body of evidence suggests that topical oxygen therapy may be considered as a second line of therapy for refractory wounds.

Effects of sevoflurane on wound healing process

BACKGROUND

Wound healing process is a tissue response to trauma which leads to tissue repair through complex biological stages. Sevoflurane is a widely used inhalation anesthetic for surgery, but there has been no study about its effect on wound healing process. This study was undertaken to evaluate the effect of sevoflurane on wound healing process.

METHODS

Male Sprague-Dawley rats (200-300 g) were used. Two circular full-thickness skin defects of 8 mm in diameter were made on dorsum of rats. After wound formation, the animals were divided into 4 groups: 1, 2, 4, 8 hr exposure to sevoflurane, respectively. Wound sizes and regional blood flow around the wounds were measured. The expression of basic fibroblast growth factor (bFGF), transforming growth factor beta1 (TGFbeta1), collagen 1, and collagen 3 mRNA were detected 7 days after wound formation by real-time reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Wound size was significantly increased in 8 hr group at 3 and 7 days after wound formation. Regional blood flow was significantly decreased in 4 hr and 8 hr groups at 3 days after wound formation. The bFGF, collagen 1 and 3 mRNA expressions were significantly decreased in 8 hr exposure group.

CONCLUSIONS

These results suggest that sevoflurane exposure influences the regional blood flow, wound size, expression of bFGF, and production of collagen 1 and 3 during the wound healing process.

Effects of sevoflurane and propofol on wound healing in rats: comparison of blood flow and wound size

BACKGROUND

As the wound healing is a multi-factorial process, the anesthetic agent and the duration of its exposure may influence the healing process after surgery. This study investigated the effect of anesthetic agents and duration of its exposure on the wound healing process after operation.

METHODS

Total 32 rats weighing 200-300 g were randomly allocated to one of eight groups according to the exposure time (1, 2, 4, 8 hours) of sevoflurane or propofol (n = 4 each). After wounding under the each anesthetic, anesthesia was maintained for 1, 2, 4 and 8 hours in each group. We compared the skin blood flow around the wound and the wound size at baseline, 3 days, and 7 days postoperatively.

RESULTS

In sevoflurane group, short exposure group (1, 2 hours) showed higher wound blood flow than long exposure (4, 8 hours) at 3 days after wounding (P < 0.05), but not at 7 days after wounding. For the wound size, there was no difference at 3 days after wounding in sevoflurane group, but 8 hours exposure group had the largest wound at 7 days after wounding. In propofol group, wound blood flow showed no difference at 3 days after wounding, but that of 4, 8 hours exposure group was higher than 2 hours exposure group at 7 days after wounding. There was no difference in wound size in propofol group.

CONCLUSIONS

This study implicates that sevoflurane might influence the wound healing process more prominently than propofol according to the duration of exposure time.

Clinical benefits after the implementation of a protocol of restricted perioperative intravenous crystalloid fluids in major abdominal operations

BACKGROUND

Perioperative fluid replacement is a challenging issue in surgical care. The purpose of the present study was to investigate the effect of two different perioperative hydration protocols on the outcome in patients undergoing major abdominal operations.

METHODS

This was a prospective study involving 61 patients (42 men/19 women; mean age: 52 years; age range: 18-81 years) who underwent major abdominal operations. The study had two distinct phases: before (conventional group; administered 30-50 ml/kg per day of crystalloid fluids; n = 33) and after the implementation of a protocol of restricted use of intravenous fluids (restricted group; administered less than 30 ml/kg per day of crystalloid fluids; n = 28). The total volume of intravenous crystalloid fluids infused was recorded until postoperative day (POD) 4. Morbidity, mortality, and the length of postoperative hospital stay were the main clinical variables.

RESULTS

Mortality was 4.9% (p > 0.05 between groups). Intravenous therapy in the restricted group was terminated earlier (p < 0.001) and the patients received 2.4 l less crystalloid fluid than did those in the conventional group from POD 1 through POD 4 (p < 0.001). The adoption of the restricted protocol shortened the postoperative hospital stay by 2 days (p = 0.02) and diminished the morbidity by 25% (p = 0.04).

CONCLUSIONS

Restriction of perioperative intravenous crystalloid fluid is associated with reductions in morbidity and length of postoperative hospital stay after major abdominal operations.

Wound healing essentials: let there be oxygen

The state of wound oxygenation is a key determinant of healing outcomes. From a diagnostic standpoint, measurements of wound oxygenation are commonly used to guide treatment planning such as amputation decision. In preventive applications, optimizing wound perfusion and providing supplemental O(2) in the perioperative period reduces the incidence of postoperative infections. Correction of wound pO(2) may, by itself, trigger some healing responses. Importantly, approaches to correct wound pO(2) favorably influence outcomes of other therapies such as responsiveness to growth factors and acceptance of grafts. Chronic ischemic wounds are essentially hypoxic. Primarily based on the tumor literature, hypoxia is generally viewed as being angiogenic. This is true with the condition that hypoxia be acute and mild to modest in magnitude. Extreme near-anoxic hypoxia, as commonly noted in problem wounds, is not compatible with tissue repair. Adequate wound tissue oxygenation is required but may not be sufficient to favorably influence healing outcomes. Success in wound care may be improved by a personalized health care approach. The key lies in our ability to specifically identify the key limitations of a given wound and in developing a multifaceted strategy to specifically address those limitations. In considering approaches to oxygenate the wound tissue it is important to recognize that both too little as well as too much may impede the healing process. Oxygen dosing based on the specific need of a wound therefore seems prudent. Therapeutic approaches targeting the oxygen sensing and redox signaling pathways are promising.

Surgical treatment of early wound complications following primary total knee arthroplasty

BACKGROUND

Wound-healing problems are a known complication after primary total knee arthroplasty. However, little is known about the clinical outcomes for patients who require surgical treatment of these early wound-healing problems. The purpose of the present study was to determine the incidence, risk factors, and long-term sequelae of early wound complications requiring surgical treatment.

METHODS

The total joint registry at our institution was reviewed for the period from 1981 to 2004. All knees with early wound complications necessitating surgical treatment within thirty days after the index total knee arthroplasty were identified. The cumulative probabilities for the later development of deep infection and major subsequent surgery were determined. A case-control study in which these patients were matched with an equal number of controls was performed to attempt to identify risk factors for the development of early superficial wound complications requiring surgical intervention.

RESULTS

From 1981 to 2004, 17,784 primary total knee arthroplasties were performed at our institution. Fifty-nine knees were identified as having early wound complications necessitating surgical treatment within thirty days after the index arthroplasty, for a rate of return to surgery of 0.33%. For knees with early surgical treatment of wound complications, the two-year cumulative probabilities of major subsequent surgery (component resection, muscle flap coverage, or amputation) and deep infection were 5.3% and 6.0%, respectively. In contrast, for knees without early surgical intervention for the treatment of wound complications, the two-year cumulative probabilities were 0.6% and 0.8%, respectively (p < 0.001 for both comparisons). A history of diabetes mellitus was identified as being significantly associated with the development of early wound complications requiring surgical intervention.

CONCLUSIONS

Patients requiring early surgical treatment for wound-healing problems after primary total knee arthroplasty are at significantly increased risk for further complications, including deep infection and/or major subsequent surgery, specifically, resection arthroplasty, amputation, or muscle flap coverage. These results emphasize the importance of obtaining primary wound-healing after total knee arthroplasty.

The effects of intraperitoneal sildenafil administration on healing of left colonic anastomoses and intra-abdominal adhesion formation in the presence of intra-abdominal infection

PURPOSE

The objective of this pilot study was to establish an animal model for intra-abdominal infection and to examine the effect of sildenafil on anastomotic healing of the left colon and intra-abdominal adhesion formation.

METHODS

Fourteen Winstar rats underwent colonic transsection and primary anastomosis after performing intra-abdominal infection. Rats were divided into two groups: Group 1 (n = 7): intra-abdominal infection, resection, and anastomoses; Group 2 (n = 7): intra-abdominal infection, resection, anastomoses, and sildenafil. Anastomotic bursting pressures, hydroxyproline levels, histopathologic grading, and abdominal adhesions were accessed on the postoperative Day 7.

RESULTS

Anastomotic healing was found to be improved in terms of a bursting pressure (P = 0.02). Histopathological examination revealed an increase in angiogenesis (P = 0.007). Moreover, intra-abdominal adhesions were significantly less in rats given sildenafil (P = 0.03).

CONCLUSION

Sildenafil may improve anastomotic healing of the left colon and diminishes peritoneal adhesion formation in the presense of abdominal infection.

Hyperoxia, endothelial progenitor cell mobilization, and diabetic wound healing

Diabetic foot disease is a major health problem, which affects 15% of the 200 million patients with diabetes worldwide. Diminished peripheral blood flow and decreased local neovascularization are critical factors that contribute to the delayed or nonhealing wounds in these patients. The correction of impaired local angiogenesis may be a key component in developing therapeutic protocols for treating chronic wounds of the lower extremity and diabetic foot ulcers. Endothelial progenitor cells (EPCs) are the key cellular effectors of postnatal neovascularization and play a central role in wound healing, but their circulating and wound-level numbers are decreased in diabetes, implicating an abnormality in EPC mobilization and homing mechanisms. The deficiency in EPC mobilization is presumably due to impairment of eNOS-NO cascade in bone marrow (BM). Hyperoxia, induced by a clinically relevant hyperbaric oxygen therapy (HBO) protocol, can significantly enhance the mobilization of EPCs from the BM into peripheral blood. However, increased circulating EPCs failed to reach to wound tissues. This is partly a result of downregulated production of SDF-1alpha in local wound lesions with diabetes. Administration of exogenous SDF-1alpha into wounds reversed the EPC homing impairment and, with hyperoxia, synergistically enhanced EPC mobilization, homing, neovascularization, and wound healing.

The management of ankle fractures in patients with diabetes

Patients with diabetes mellitus have higher complication rates following both open and closed management of ankle fractures. Diabetic patients with neuropathy or vasculopathy have higher complication rates than both diabetic patients without these comorbidities and nondiabetic patients. Unstable ankle fractures in diabetic patients without neuropathy or vasculopathy are best treated with open reduction and internal fixation with use of standard techniques. Patients with neuropathy or vasculopathy are at increased risk for both soft-tissue and osseous complications, including delayed union and nonunion. Careful soft-tissue management as well as stable, rigid internal fixation are crucial to obtaining a good outcome. Prolonged non-weight-bearing and subsequently protected weight-bearing are recommended following both operative and nonoperative management of ankle fractures in patients with diabetes.

Changes in optical properties of tissue during acute wound healing in an animal model

Changes of optical properties of wound tissue in hairless rats were quantified by diffuse photon density wave methodology at near-infrared frequencies. The diffusion equation for semi-infinite media was used to calculate the absorption and scattering coefficients based on measurements of phase and amplitude with a frequency domain device. There was an increase in the absorption and scattering coefficients and a decrease in blood saturation of the wounds compared with the nonwounded sites. The changes correlated with the healing stage of the wound. The data obtained were supported by immunohistochemical analysis of wound tissue. These results verified now by two independent animal studies could suggest a noninvasive method to detect the progress of wound healing.

Laryngeal reconstruction following shrapnel injury in a British soldier: case report

INTRODUCTION

Laryngeal injuries are uncommon but result in high mortality and morbidity rates when they do occur. We report a case of laryngeal fracture due to penetrating shrapnel injury, repaired with miniplates.

CASE REPORT

A 26-year-old soldier was involved in an explosion and sustained a shrapnel wound to his right neck. After immediate airway management at the field hospital he was transferred to the UK, where he underwent a neck exploration, laryngofissure and repair of the thyroid cartilage using miniplates. An endolaryngeal stent was placed, which was removed at a second operation seven days later. Post-operatively, the patient recovered well and his voice improved rapidly. Six months post-operatively, he returned to work.

DISCUSSION

The cause and nature of laryngeal injury differs between wartime and peacetime. The methods of diagnosis and management strategies are reviewed. The early recognition of injury and protection of the airway are of paramount importance when dealing with laryngeal injury. Delayed laryngeal reconstruction using miniplates can give a good functional result.

Complications of ankle fracture in patients with diabetes

Ankle fractures in patients with diabetes mellitus have long been recognized as a challenge to practicing clinicians. Complications of impaired wound healing, infection, malunion, delayed union, nonunion, and Charcot arthropathy are prevalent in this patient population. Controversy exists as to whether diabetic ankle fractures are best treated noninvasively or by open reduction and internal fixation. Patients with diabetes are at significant risk for soft-tissue complications. In addition, diabetic ankle fractures heal, but significant delays in bone healing exist. Also, Charcot ankle arthropathy occurs more commonly in patients who were initially undiagnosed and had a delay in immobilization and in patients treated nonsurgically for displaced ankle fractures. Several techniques have been described to minimize complications associated with diabetic ankle fractures (eg, rigid external fixation, use of Kirschner wires or Steinmann pins to increase rigidity). Regardless of the specifics of treatment, adherence to the basic principles of preoperative planning, meticulous soft-tissue management, and attention to stable, rigid fixation with prolonged, protected immobilization are paramount in minimizing problems and yielding good functional outcomes.

Prediction Of Surgical Site Infections After Major Surgery Using Visible And Near-Infrared Spectroscopy

Final results of an investigation into whether oxygen saturation of tissues (StO2, measured by spectrophotometry) could predict surgical site infections (SSI) after major abdominal surgery are presented. StO2 was measured on the arm and wound site pre-operatively and then at 12, 24 and 48 hours post-operatively. A Whitland Research RM200 was employed as the visible lightguide spectrophotometer. StO2 measurements using this machine were designated SSO2 (skin SO2). A Hutchinson Inspectra Model 325 was used for the near infrared spectroscopy (NIS) measurements. StO2 measurements using this machine were designated MSO2 (muscle SO2). Of 59 patients (38 males, 21 females), 42 healed uneventfully and 17 developed SSI. The overall infection rate was 28.8%. No significant differences were seen in wound SSO2 between outcome groups at any stage. At 12 hours there was a significant difference between the two groups with respect to mean wound MSO2 (A = 58.3 +/- 21.6%, B = 42.2 +/- 16.6%, p = 0.005, 95% confidence interval = 5.26, 26.98). A receiver operating characteristic curve showed that when a wound MSO2 of 53% was chosen as the threshold to classify potential infection a sensitivity of 71% and a specificity 73% (chi-squared test, p = 0.002) was achieved. The use of the near-infrared spectrophotometry as a tool to predict wound infections should be further evaluated and advocated.

Optimizing the patient for surgical treatment of the wound

Plastic surgeons are consulted often to close wounds that fail or are difficult to heal. Optimizing the patient's medical condition before surgical closure of a wound can mean the difference between a successful outcome and an undesirable one. It is imperative that plastic surgeons have an extensive knowledge of the modifiable risk factors affecting the wound-healing process and their subsequent complications. This knowledge allows the surgeon to tailor the treatment options and intervene when appropriate to optimize outcomes for successful surgical closure of a wound. Whether the impairments to wound healing and closure are local or systemic, they must be addressed appropriately.