Utilization of a 3D Printed Simulation Training Model to Improve Microsurgical Training.

Simulation is integral to the development and maintenance of micro- surgical skills. Several simulation models have been described ranging from bench- top to live animal models. High fidelity models are often burdened by cost and ethical issues limiting widespread implementation. This study aims to determine the feasibility of a microsurgical training platform using the Konjac noodle model. Methods: A prospective cohort study was conducted at our institution. A progressive microsurgical training curriculum was developed. A bespoke three-dimensional printed training platform was produced to enable residents to record training and assessment tasks. Microsurgical skills were blindly assessed before and after completing the training program using the University of Western Ontario Microsurgical Skills Assessment instrument. Results: Plastic surgery residents at various stages of training were recruited (n = 10). A significant improvement in vessel preparation from a pre-training median of 3 (IQR 2 -4) versus a post-training of 4 (IQR 3 -5, P = 0.0035) and suturing with a pre-training median of 3 (IQR 2 -4) versus a post-training of 4 (IQR 3 -5, P = 0.0047) domains of the University of Western Ontario Microsurgical Skills Assessment score was demonstrated after completion of the training program. There was a significant improvement in the global rating score (3 ± 1 versus 5 ± 1, P = 0.0045). Participants felt more confident performing a microsurgical anastomosis following the training program. Conclusion: The use of the Konjac noodle model and video-based assessment using a three-dimensional printed model is an effective teaching tool that improves resident's microsurgical skills.

The inferior mesenteric vessels as recipients when performing free tissue transfer for pelvic defects following abdomino-perineal resection. A novel technique and review of intra-peritoneal recipient vessel options for microvascular transfer.

Successful microvascular transfer of tissue is dependent upon suitable vessels not only of the donor tissue but also at the recipient site. Congenital deformities, previous surgery, infection or irradiation at the recipient site may render vessels less suitable for this purpose. Under such circumstances it becomes desirable to identify suitable recipient vessels remote to the compromised area. In cases where external beam radiotherapy has been delivered, the superficial surface area damaged can be rather extensive precluding the use of even the longest of flap pedicles--a problem potentially addressed by searching for recipient vessels deep to the tissue planes affected. We report one such case where the inferior mesenteric vessels were used as recipient vessels for the microvascular transfer of a free Latissimus Dorsi musculocutaneous flap to reconstruct an extensive perineal defect following abdomino-perineal resection where the vessels would otherwise serve no purpose. Whilst a limited number of intra-peritoneal vessels have previously been reported as recipient vessels for free flap surgery there has not been, to our knowledge, any report of utilising the inferior mesenteric artery (Inf Mes A). Whilst based on a single case report, this article examines the literature describing microvascular transfer of tissue to compromised recipient sites and it reviews previously reported recipient vessel options available when reconstructing the perineum, abdominal wall or trunk with particular emphasis on intra-peritoneal options.

Reconstruction of the perineum following anorectal cancer excision.

PURPOSE: Most patients with anal cancer receive chemoradiotherapy as first-line treatment. Persistent/recurrent tumours will subsequently require an abdomino-perineal resection (APR). A proportion of the 20,000 new cases of rectal carcinoma diagnosed in the UK each year receive neo-adjuvant chemoradiation and then an APR. Healing of the irradiated perineal bed is compromised, resulting in high morbidity. Reconstruction of the perineam with well-vasularised tissue is thought to enhance healing. This study investigates a series of 18 patients who underwent APR for anorectal cancer with flap reconstruction of their perineum. MATERIALS AND METHODS: A retrospective analysis of all anorectal cancers requiring an APR and flap reconstruction was performed. Casenotes were reviewed and documentation made of risk factors putting them at increased risk of wound complications. Length of stay, morbidity and outcome variables including primary flap healing were recorded. RESULTS: Between November 2000 and October 2007, 18 cases were performed (M/F = 7:11), six for anal cancer and 12 for low rectal tumours. Pre-operative treatment was chemoradiotherapy in 14 (78%), radiotherapy alone in two (11%) and none in two (11%). Perineal reconstruction consisted of 14 vertical rectus abdominis myocutaneous flaps, three free latissimus dorsi flap and one transverse rectus abdominis myocutaneous flap. Mean hospital stay was 21.8 days (10-54 days). Complete healing was noted in 16 cases with the remaining two continuing to improve under current follow-up. There were no flap losses. CONCLUSIONS: Despite most patients being treated with pre-operative radiotherapy, we have had significant success in obtaining primary healing of the perineal defect after APR.

In vivo gene delivery of Ad-VEGF121 to full-thickness wounds in aged pigs results in high levels of VEGF expression but not in accelerated healing.

We have previously reported that endogenous vascular endothelial growth factor (VEGF) concentration in older pig wounds peaked later and at one-fourth the level of young pigs. These data suggested that VEGF might play a major role in the healing of full-thickness wounds in the aged pig. By in vivo gene transfer using the microseeding technique, we treated full-thickness wounds with different doses of VEGF-expressing adenoviral vector (Ad-VEGF) varying from 1 x 10(7) to 2.7 x 10(11) particles per wound (ppw). We found that the VEGF expression in wound fluid followed a dose-response pattern. However, when wounds were microseeded with the highest concentration of Ad-VEGF (2.7 x 10(11) ppw), diminished healing rates were found. We then determined the minimal functional concentrations of Ad-VEGF. We used five aged Yucatan minipigs, all retired breeders, to analyze the role of over-expression of 1 x 10(8) and 1 x 10(9) ppw of Ad-VEGF (n= 78) in terms of healing of full-thickness wounds, all 2.5 x 2.5 x 1 cm in size (n= 158). The Ad-VEGF solutions were delivered to the wound floor and borders by in vivo microseeding. Control wounds (n= 80) were microseeded with Ad-Lac-Z (n= 25), treated with saline (n= 49) or treated dry (n= 6). All wounds except for the dry-treated ones were covered with a wound chamber and a wet environment was created by injecting 2.5 ml saline into the chamber. Peak VEGF expression (2300-4000 pg/ml) was detected on days 2 or 3 post gene delivery. This level of VEGF expression was not seen in the saline (n= 49) or Ad-null (n= 25) control groups. The VEGF expression in wounds treated with 1 x 10(8) and 3 x 10(8) ppw (n= 39) exhibited a slower onset with a peak concentration of 400-920 pg/ml on days 5-7. Although high levels of VEGF expression were achieved in the local wound environment, we could not show a significant increase in neovascularization as compared to saline-treated wounds. No significant differences were observed in the rate of reepithelialization and wound contraction among groups of full-thickness wounds treated with Ad-VEGF, Ad-null mutant, or saline in the aged "wet wound healing" pig model. These results indicate that increased levels of VEGF in wounds produced by in vivo gene transfer have little effect on the healing of full-thickness wounds in the aged pig model. Moreover, significantly higher levels of VEGF expression by Ad-VEGF could lead to impaired wound healing.

Gene therapy in wound healing.

Gene therapy is a new and emerging technology that has been catalyzed by the progress of the Human Genome Project. It employs the process of manipulating genes to achieve a clinically beneficial alteration in gene product. Wound healing lends itself to the application of gene therapy by virtue of the vast array of proteins involved in its complex cascade. This article provides an overview of the background to gene therapy and describes current techniques in use as applied to wound healing. The authors show the potential role that many candidate genes may offer in the future for optimizing wound healing through gene therapy.

Gene therapy in soft tissue reconstruction.

Gene therapy is defined as the introduction of a therapeutic gene into a cell, whose expression can lead to a cure of a disease or offer a transient advantage for tissue growth and regeneration. The delivery of genes can be undertaken for a number of purposes, usually it is attempted to enhance or add a function to a cell or a tissue or to delete or reduce another function. In this brief overview we describe various vehicles and techniques that have been developed to deliver therapeutic genes into cells, such as viral vectors and physical/chemical gene delivery methods including naked DNA and particle-mediated gene transfer, the microseeding technique and the application of lipids. Furthermore we review the potential utility of gene therapy from the perspective of a reconstructive surgeon. Several tissues will be discussed, particularly muscle, tendon, nerve, bone, skin and wounds.