Re-raising muscle flaps: A randomised controlled animal study.

BACKGROUND: In the experience of our centre, 33% of reconstructed compound lower limb injuries will need an orthopaedic revision.1 A flap may be re-raised through numerous methods, and historically, the approach of choice has been based on the principle of protecting the vascular pedicle rather than the inset. Our aim was to determine whether a marginal versus a split approach to re-raising inferred a higher risk of flap necrosis and whether more attention should be paid to protecting the inset of the flap, particularly at the distal portion. METHOD: A pedicled pectoralis profundus muscle flap was raised in 32 Sprague-Dawley rats and transposed to the lateral chest wall. After 21 days, the flaps were randomised into one of four treatment groups according to the surgical approach and whether or not the anatomical vascular pedicle was ligated. Necrosis was assessed 48 h later, both clinically and through the analysis of digital photographs. RESULTS: The rate of necrosis in the marginal group was higher than that in the split group (63% vs 0%, p < 0.001, McNemar). More necrosis occurred in the former when the pedicle was ligated (p < 0.001, Fisher's exact test). Measured necrosis was also higher in the marginal group (18% vs 0%, p = 0.002, Wilcoxon signed-rank test). Twenty-nine percent more flap could be raised using the split approach (p = 0.001, Mann-Whitney U test). CONCLUSIONS: Splitting a muscle flap produces significantly less necrosis than incising the inset, regardless of whether the pedicle is in flow. It also offers wider exposure of structures deep to the flap. These findings provide a detailed model for human trials, which is presented as a proposed management algorithm. It also highlights conditions that must be met for translation to a human population.

Perfusion of muscle flaps independent of the anatomical vascular pedicle: Pedicle autonomy.

INTRODUCTION: Free muscle flaps are being used more commonly for complex lower limb reconstruction. Up to 33% of flaps used to reconstruct lower limb trauma will require an orthopaedic procedure after reconstruction. To date there have been only case reports detailing the variable survival of muscle flaps after actual or simulated pedicle injury and the process and timeframe of neovascularisation remains undefined. We aim to show that perfusion of a muscle flap is possible after injury to its anatomical vascular pedicle. METHODS: Pedicled muscle flaps were raised and transposed to a cutaneous inset on the chest wall in a rodent model. Each flap was subjected to simulated pedicle injury at a variable time. Allocation was by computer randomisation. Flap perfusion was assessed before and after pedicle injury followed 48 h later by sacrifice of the animal and static angiography of the flaps. RESULTS: By the 21st day after inset, all flaps survived simulated pedicle injury. Prior to this, flap survival was significantly lower (p = 0.017, Fisher's Exact Test). Clinical signs at the time of pedicle injury did not predict flap survival. Most new vessels form at the distal part of the inset (p < 0.01, ANOVA). The total number does not change with time (p = 0.82, ANOVA). New vessels anastomose preferentially with skin. The fall in perfusion after pedicle ligation was significant for all groups except the day 35 group (p = 0.53). CONCLUSIONS: Muscle flaps can perfuse after an injury to the anatomical vascular pedicle through neovascularisation at the inset. These new vessels are evident early but may not function adequately to perfuse the flap. Regional variations in neovascularisation suggest that a gradient of ischaemia drives this process. Inset at the cutaneous level is important, which has implications for buried muscle flaps. The correlation between change in flap perfusion after pedicle injury and flap necrosis suggests a role for the former in determining the capacity of a muscle flap to tolerate a pedicle injury and thereby the approach to re-raising it.

Diphenylcyclopropenone for the treatment of cutaneous in-transit melanoma metastases - results of a prospective, non-randomized, single-centre study.

BACKGROUND: Current treatments for in-transit melanoma (ITM) metastases are frequently invasive and do not improve overall survival. Recently, there has been increasing investigation into the use of topical agents. Diphenylcyclopropenone or diphencyprone (DPCP) is a novel, topical therapy that has been reported to have immune-sensitizing properties useful in the treatment of ITM. OBJECTIVE: To assess the clinical outcomes of patients treated within a prospective, non-randomized, non-comparative study using DPCP for cutaneous ITM metastases. METHODS: A review was conducted assessing the outcomes of 58 patients prospectively treated using DPCP. Patients had satellite or in-transit disease (stage IIIB+), with all lesion morphology types included. The patients were treated through a single, specialized clinic with regular outpatient follow-up. DPCP was topically applied as an aqueous cream in 0.005-1% concentrations once to twice per week for up to 24-48 h of duration. To assess variables associated with response, a per-protocol statistical analysis was performed. RESULTS: Fifty-four patients were treated who satisfied eligibility criteria for analysis. The overall response rates were as follows: complete response 22%, partial response 39%, stable disease 24% and progressive disease 15%. The mean time to complete response was 10.5 months, mean duration (disease-free interval) 12.3 months and recurrence rate in complete responders 41%. Lesion morphology was predictive of clinical benefit with a higher response in epidermotropic disease (P < 0.05). CONCLUSIONS: DPCP provided a well-tolerated, convenient and efficacious treatment for cutaneous ITM metastases. Identifying patterns of response may assist treatment selection and improve patient-rated outcomes.

A systematic review of non-surgical treatments for lentigo maligna.

Lentigo maligna (LM) is the most common melanocytic malignancy of the head and neck. If left untreated, LM can progress to lentigo maligna melanoma (LMM). Complete surgical excision is the gold standard for treatment, however, due to the location, size, and advanced age of patients, surgery is not always acceptable. As a result, there is ongoing interest in alternative, less invasive treatment modalities. The objective was to provide a structured review of key literature reporting the use of radiotherapy, imiquimod and laser therapy for the management of LM in patients where surgical resection is prohibited. An independent review was conducted following a comprehensive search of the National Library of Medicine using MEDLINE and PubMed, Embase, Scopus, ScienceDirect and Cochrane Library databases. Data were presented in tabular format, and crude data pooled to calculate mean recurrence rates for each therapy. 29 studies met the inclusion criteria: radiotherapy 10; topical imiquimod 10; laser therapies 9. Radiotherapy demostrated recurrence rates of up to 31% (mean 11.5%), with follow-up durations of 1-96 months. Topical imiquimod recurrence rates were up to 50% (mean 24.5%), with follow-up durations of 2-49 months. Laser therapy yielded recurrence rates of up to 100% (mean 34.4%), and follow-up durations of 8-78 months. in each of the treatment series the I(2) value measuring statistical heterogeneity exceeded the accepted threshold of 50% and as such a meta-analysis of included data were inappropriate. For non-surgical patients with LM, radiotherapy and topical imiquimod were efficacious treatments. Radiotherapy produced superior complete response rates and fewer recurrences than imiquimod although both are promising non-invasive modalities. There was no consistent body of evidence regarding laser therapy although response rates of up to 100% were reported in low quality studies. A prospective comparative trial is indicated and would provide accurate data on the long-term efficacy and overall utility of these treatments.

Predicting venous insufficiency in flaps raised on the deep inferior epigastric system using computed tomography (CT) angiography.

Computed Tomography Angiogram (CTA) has become a routine part of pre-operative assessment of vascular anatomy and design in perforator flaps. We conducted a retrospective cohort study of flap raised on the deep inferior epigastric system (DIES) at our institution in order to identify CTA signs that might predict venous congestion in these flaps. 98 consecutive patients who had 124 DIES flaps raised from 2008 to 2012 were studied. Of these 124 flaps, four (3.2%) developed venous congestion. Our results showed that a Superficial Inferior Epigastric Vein (SIEV) that is larger than the DIEV at origin is highly predictive of congestion (5.2 vs 3.5 mm, p = 0.007). The findings of an axial non-arborising superficial system (96.7% vs 0, p < 0.001), without connection to deep system perforators (38.1 vs 88.8%, p < 0.001) and a type I pedicle were also predictive (75 vs 64.2%, p = 0.22). These results show the importance of CTAs as a pre-operative study for the identification of risk factors for venous compromise, and their use should prompt a robust discussion of the risk of flap failure with patients, and contingency planning to augment venous drainage with the superficial system if required.