Plaster Burn: Challenge to Plastic Surgeon

BACKGROUND

The thermal burn is accidental and also is the hidden and worst complication of medical plaster application. This study evaluated clinical and aetiological profile and severity of plaster burns.

METHODS

In Department of Burns, Plastic and Reconstructive Surgery from 1^st August 2014 to 31^st December 2015, six patients with plaster burn were assessed for total body surface area and depth of burn. The wounds were cultured and dressed with moist dressings daily till the surgical procedure and satisfactory healing.

RESULTS

The youngest patient was 10 and oldest 65 years (mean age: 40.20±6.67 years, 4 males and two females with ratio of 2:1). Three patients sustained plaster burn injury accidentally at home and 3 developed burn after medical application of plaster. The hands burns were observed commonly in accidental plaster burns, while ankle was often involved in iatrogenic plaster burns. The iatrogenic burns were mostly deep in thickness varying 2^nd to 4^th degree, while accidental burns were often 2^nd degree. Superficial 2^nd degree burns were managed conservatively, and deep 2^nd degree burns were skin grafted. Fourth degree burn was managed with reverse sural flap alone and another with vacuum-assisted closure followed by reverse sural flap and skin grafting.

CONCLUSION

Plaster burn is still a challenge to plastic surgeon and it is advised for applying casts to utilize all available means to limit the amount of casting material provided. It can be accomplished without compromising the cast strength to minimize the risk of thermal injury when applying plaster or composite casts.

The fortune cookie flap for aesthetic reconstruction after chest keloid resection: a small case series

Background

Generally, the recurrence rate of keloids is unacceptably high after surgical excision alone. Nevertheless, surgical reduction of keloids is inevitable in many cases. The reconstruction of extensive soft tissue defects following complete keloid resection is challenging to surgeons. In this study, we present our clinical experience using a novel fortune cookie flap for treating chest keloids. This flap provides an excellent surgical option that maintains natural appearance with minimal donor-site morbidity.

Methods

We retrospectively reviewed the data from 3 consecutive cases of reconstruction using the fortune cookie flap following resection of chest keloids between March and December, 2017.

Results

Successful reconstructions were performed without any major complications. The mean dimensions of the reconstructed defect were 5.0 × 4.2 cm, while the mean dimensions of the flap were 7.7 × 5.7 cm.

Conclusions

Owing to its simplicity, reliability, versatility, minimal morbidity and excellent aesthetics, the fortune cookie flap is as an excellent option for reconstruction following complete keloid resection on the chest.

Electronic supplementary material

The online version of this article (10.1186/s13019-018-0713-x) contains supplementary material, which is available to authorized users.

Aesthetic considerations in flap reconstruction of the burnt face in males: A demonstrative case report

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A man presented with a deep burn of the right side of the face.

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Reconstruction was initially done with a latissimus dorsi free flap.

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The aesthetic outcome was poor.

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Salvage was done using a superficial temporal artery flap.

Introduction

The face is unique because functional and aesthetic considerations are equally important. Extensive deep chemical burns of the face are usually reconstructed with flaps. In males, the use of the hair – bearing superficial temporal artery flap has the advantage of achieving a satisfactory outcome with regards to both function and aesthetics.

Presentation of case

A 49-year-old man sustained a deep chemical burn to the right side of the face and neck. The resulting right peri-oral and neck contractures were initially reconstructed with a latissimus dorsi myo-cutaneous free flap. The functional outcome was satisfactory. The cosmetic outcome was poor and caused the patient to go into depression. Salvage was done using a hair-bearing superficial temporal artery flap.

Discussion

In males, the use of the hair-bearing superficial temporal artery flap in facial reconstruction respects the aesthetic units and is also able to achieve a satisfactory functional outcome.

Conclusion

We stress that aesthetic and functional considerations are equally important in facial reconstruction. In males, the hair-bearing superficial temporal artery flap is the flap of choice if the beard/moustache areas are involved.

Negative pressure wound therapy versus conventional wound dressings in treatment of open fractures: A systematic review and meta-analysis

BACKGROUND

Though several systematic reviews concerned have been published, controversy still exists. The current systematic review was designed to clarify the detailed advantages and disadvantages of the negative pressure wound therapy (NPWT) in treatment of open fractures in comparison with the conventional wound dressings.

METHODS

A systematic search was performed in Pubmed, Cochrane Library, Embase, and Google Scholar for the published relevant clinical studies. Unpublished studies were searched in Clinicaltrials, ICTRP and ISRCTN. The outcome measures included presence of infection, wound healing process, length of the patient hospital stay, flap issues, frequency of amputation, and patient life quality.

RESULTS

In the 8 randomized controlled trials (RCTs) (421 patients) and the 6 retrospective cohort studies (488 patients), NPWT resulted in a significantly lower infection rate, significantly shorter wound coverage time, wound healing time and hospital stay length, and the lower amputation rate. However, no statistically significant difference was found in the need for flap surgery, the proportion of free flaps, the flap failure rate or the fracture non-union rate. Only 1 RCT was reported to have a higher physical component score of short form 36 in the infected patients.

CONCLUSION

NPWT can significantly reduce the risk of infection in treatment of open fractures and accelerate their wound healing process. Some but not much evidence suggests that NPWT may possibly help reduce the severity of the limb injury and therefore provide a chance for the limb to avoid amputation. Use of NPWT in the flap area is probably safe, but should be carried out with caution. The advantage of NPWT over the conventional wound dressings still requires to be confirmed in the other aspects.

Traumatic Wounds of the Upper Extremity: Coverage Strategies

Soft tissue coverage of traumatic wounds of the upper extremity is often required to restore adequate function and form. An optimal coverage should be stable, durable, and able to withstand heavy demands of work, should allow free joint mobility, and should have an aesthetically acceptable appearance. Reconstructive options for coverage include autologous tissue and dermal skin substitutes. Multiple factors, including wound characteristics and complexity, general condition of the patient, and surgeon comfort and expertise, help in selection of the reconstructive technique. This article summarizes commonly used soft tissue reconstructive options for traumatic wounds of the upper extremity.

Synchronous Soleus and Reverse Sural Flap for Large Soft Tissue Defect Reconstruction of Leg

BACKGROUND

Extended Soft tissue defect of leg including middle and distal parts always has been a challenge for many plastic surgeons and also a frustrated problem for patients and families. To introduce the use of the soleus muscle and reverse sural flaps as synchronous surgical treatment alternative of the leg bone exposure with large soft tissue defect, this study was conducted.

METHODS

The medical records of patients undergoing transposition of the soleus muscle for treating exposed bone in the leg and simultaneous sural flap were retrospectively analyzed from January 2009 to July 2014, while gathering information on the used muscle was to cover the lesion.

RESULTS

Twelve patients with varying ages between 22 and 58 years (10 males and 2 females) were enrolled. The main initial injury was trauma (84.8%), consisting of tibia and/or fibula fractures. Only 1 patient developed insignificant distal flap necrosis who was treated subsequently with surgical debridement and flap re-advancement.

CONCLUSION

The treatment of bone exposure with local muscle flaps (soleus and sural) enables obtaining satisfactory results in covering of exposed structures, favoring local vascularization and improving the initial injury. It offers the advantage of providing a treatment in only one surgical procedure, an earlier recovery and reduced hospital stay. Sometimes, this method may be applied instead of free tissue transfer.

Time of return back to work and complications following cross-finger flaps in industrial workers: Comparison between immediate post operative mobilization versus immobilization until flap division

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Previous authors have immobilized the hand following cross finger flaps.

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We studied two groups of injured industrial workers.

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Group I (n = 12) had immediate postoperative mobilization.

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Group II (n = 12) had immobilization till the time of flap division.

•

Complications were similar but Group I returned back to work earlier.

Introduction

Previous authors have immobilized the injured hand or digits following cross finger flaps.

Patients and methods

About 3 years ago, the author adopted a protocol of immediate postoperative active and passive mobilization (without a splint) following cross finger flap surgery in industrial workers. The current study is a retrospective audit comparing postoperative complications and time of return back to work following cross-finger flaps in two groups of injured industrial workers: Group I (n = 12) had immediate postoperative mobilization; and Group II (n = 12) had immobilization till the time of flap division.

Results

The complication rate was similar in both groups. However, patients in Group I returned to work earlier than those in group II and the difference was statistically significant.

Conclusion

Immediate postoperative mobilization following cross-finger flaps in industrial workers does not increase the risk of complications and has the advantage of early return to work.

Anatomical study of medial sural artery and its perforators in Nepalese: an aid to reconstructive surgery

OBJECTIVE

The present study was undertaken to know the anatomical basis of medial sural artery (MSA) and its perforators in Nepalese.

METHODS

The popliteal arteries of 16 preserved cadaveric lower limbs were injected with a mixture of red ink and glycerine. The number, location, diameter of perforators; length and intramuscular course of pedicle; the branching pattern of MSA were observed and measured.

RESULTS

The mean of 2.2 ± 1.2 perforators (range 0-4) was observed. The perforators were clustered between 8.6 and 25.7 cm from the popliteal crease and 0.3-7.5 cm from posterior midline of leg. The dominant perforators were observed in middle 1/3rd of the leg. The average pedicle length was 12.04 ± 3.27 cm. The intramuscular courses of pedicles were observed in deep and superficial strata in 65.7 and 34.3%, respectively. The MSA originated from popliteal artery in 62.5% and common sural artery in 37.5%. An accessory MSA was found in 12.5%. Type I and Type III branching patterns of MSA were observed in 31.2% each whereas Type II was found in 37.5%. The mean external diameter of perforators and MSA were 0.85 ± 0.27 mm and 2.2 ± 0.43 mm, respectively.

CONCLUSIONS

The metrical presentation of this study provides an easy access to know about the distribution of perforators and branching pattern of MSA which will help the surgeons to make a convenient plan to harvest the MSA perforator flap in Nepalese population.

Total elbow arthroplasty under unfavourable soft tissue conditions

PURPOSE

To evaluate the clinical and radiographic outcomes of patients with total elbow arthroplasty (TEA) and soft tissue reconstruction.

METHODS

We investigated six patients who underwent TEA and soft tissue reconstruction (two elbows with 1-stage surgery and four elbows with 2-stage surgery). The mean patient age at the time of the surgical procedure was 43.2 years; the mean follow-up duration was 88.2 months.

RESULTS

The mean pain visual analogue scale (VAS) during motion was improved from 6.3 pre-operatively to 0.7 at the last follow-up. The mean Mayo Elbow Performance Score (MEPS) improved from 26.7 pre-operatively to 81.7 at the last follow-up. The mean flexion-extension arcs of the 1- and 2-stage surgery groups increased from 12.5° and 13.8° pre-operatively to 72.5° and 100° at the last follow-up, respectively. The mean MEPS of the one and two stage surgery groups were 75 and 85, respectively, at the last follow-up. One of the six elbows had loosening on the simple radiograph at the last follow-up, and there were no cases with bushing wear. Three elbows needed additional skin debridement owing to wound complications (2/2 elbows in the 1-stage surgery group and 1/4 elbows in the 2-stage surgery group).

CONCLUSIONS

Under unfavorable soft tissue conditions, performing soft tissue reconstruction with TEA provides satisfactory functional improvement and pain relief. The two stage surgery provided a lower rate of wound complication and better elbow function than the one stage surgery, which led to high patient satisfaction post-operatively.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Rotational gluteal flap versus modified Limberg flap in treatment of sacrococcygeal pilonidal disease

BACKGROUND

Sacrococcygeal pilonidal disease (SPND) is a common surgical condition with a multitude of surgical treatments. The aim of this study was to compare the outcome of modified Limberg flap (MLF) and that of rotational gluteal flap (RGF) in treatment of SPND.

MATERIALS AND METHODS

This was a retrospective case-controlled study involving adult patients of both genders who were treated with either MLF or RGF for SPND. The main outcomes of the study were the recurrence of SPND, complications, operation time, hospital stay, time of healing, time to return to daily activities, and cosmetic outcomes.

RESULTS

A total of 189 (143 males) patients with a mean age of 23.5 y were included. Ninety-five patients were treated with RGF (cases), and 94 were treated with MLF (controls). Both the groups were matched regarding age, gender, body mass index, and disease severity. The operation time of RGF was longer than that of MLF (P < 0.0001). No significant difference in recurrence was noted between RGF and MLF (3.1% versus 7.4%, P = 0.21). RGF had lower complication rate than MLF (17.9% versus 40.4%; P = 0.001). Time to return to work was similar in both the groups. RGF conferred significantly better cosmetic outcomes than MLF.

CONCLUSIONS

Both RGF and MLF achieved comparable, low recurrence rates. Although the operation time of RGF was significantly longer than that of MLF, the RGF had shorter healing time; lower complication rate, particularly seroma formation; and better cosmetic appearance.

Temporal and Spatial Flap Variability in Laser In-Situ Keratomileusis by Optical Coherence Tomography

Purpose:

To study changes in flap thickness made with two different microkeratome heads across different corneal locations using anterior segment optical coherence tomography (OCT).

Methods:

In this prospective, non-randomized, consecutive case series, subjects who had their laser in-situ keratomileusis (LASIK) flaps made using 90 μm (MSU90) or 130 μm (MSU130) disposable M2 microkeratome heads were examined using OCT. The measurements were performed at three locations (central and 2.5 mm to either side) at 1 day, 1 week, and 1 month postoperatively.

Results:

The central flap thickness was 123 ± 15, 130 ± 14, and 127 ± 13 μm, respectively, at 1 day, 1 week, and 1 month postoperatively in the MSU90 group (41 eyes) and 142 ± 20, 147 ± 19, and 143 ± 15 μm, respectively, in the MSU130 group (47 eyes). At 1 month, peripheral flap thickness was 161 ± 17 and 159 ± 13 μm, respectively, at 2.5 mm to the right and left of corneal center in the MSU90 group. The corresponding figures were 170 ± 14 and 167 ± 13 μm, respectively, in the MSU130 group. There was a statistically significant difference between the two groups at all locations (P < 0.001). No statistically significant change in flap thickness was detected in either group at any assessment time. There was a partial positive correlation (after controlling for preoperative manifest refractive spherical equivalent) between central flap thickness and preoperative ultrasound central pachymetry (r = 0.739, P = 0.036) in the MSU90 group but not in the MSU130 group.

Conclusion:

Using OCT, changes in flap thickness were minimal in the first month after LASIK. Flap thickness correlated strongly with central corneal thickness if a 90 μm head was used.

The Effect of Low-Dose Nitroglycerin Ointment on Skin Flap Necrosis in Breast Reconstruction after Skin-Sparing or Nipple-Sparing Mastectomy

Background

Skin flap necrosis is a common complication after mastectomy and breast reconstruction. It has been proven that nitroglycerin ointment, as a topical vasodilator, can decrease the rate of skin flap necrosis after mastectomy and breast reconstruction. However, nitroglycerin can cause several side effects, including headache, dizziness, and hypotension. The purpose of this study was to evaluate whether the application of a low dose of nitroglycerin ointment reduced the rate of skin flap necrosis in breast reconstruction after skin-sparing or nipple-sparing mastectomy.

Methods

A total of 73 cases of breast reconstruction after nipple-sparing and skin-sparing mastectomy at our institution from March 2012 to January 2017 were retrospectively studied. Of these patients, 52 received nitroglycerin ointment (4.5 mg) application to the skin around the nipple-areolar complex from August 2015 to January 2017, while 21 received fusidic acid ointment from March 2012 to August 2015. The number of patients who experienced necrosis of the breast skin flap was counted in both groups.

Results

Skin flap necrosis developed in 2 (3.8%) patients who were treated with nitroglycerin ointment and 5 (23.8%) patients who did not receive nitroglycerin ointment treatment. Patients who did not receive nitroglycerin ointment treatment had a significantly higher risk of mastectomy skin flap necrosis than patients who did (odds ratio=7.81; 95% confidence interval, 1.38 to 44.23; P=0.02).

Conclusions

Low-dose nitroglycerin ointment administration significantly decreased the rate of skin flap necrosis in patients who underwent breast reconstruction after skin-sparing or nipple-sparing mastectomy, without increasing the incidence of the side effects of nitroglycerin.

Multiple extensor tendons reconstruction with hamstring tendon grafts and flap coverage for severe dorsal hand injuries

Treatment of patients with traumatic loss of skin and multiple extensor tendons on the dorsum of the hand is a challenge. The aim of this study was to assess the outcome after reconstruction of soft tissues and multiple extensor tendons in patients who suffered traumatic loss of skin and multiple extensor tendons. Ten patients were enrolled in the study. These patients underwent single-stage reconstruction with autogenous hamstring tendon grafts for multiple extensor tendon defects and fasciocutaneous flaps for coverage of dorsal hand defects. In total, 25 tendons (2 tendons in 5 patients and 3 tendons in 5 patients) were reconstructed. The semitendinosus tendon was used in all patients and the gracilis tendon was added in five patients for tendon reconstruction. Total tendon length requiring reconstruction was between 9cm and 31cm. Free anterolateral thigh flaps were used in six patients and reverse pedicled forearm flaps were used in four patients. According to Miller's scoring system, 8 fingers had excellent results, 12 fingers had good results and 5 fingers had fair results at the final follow-up. Hamstring tendons can be used satisfactorily for primary reconstruction of multiple digital extensor tendons due to their availability and compatibility, with a fasciocutaneous flap.

LEVEL OF EVIDENCE

IV.

Low recurrence rate of anchored conjunctival rotation flap technique in pterygium surgery

Background

To report the recurrence rate for an anchored conjunctival rotation flap technique in primary pterygium surgery.

Methods

Primary pterygium surgeries performed using anchored conjunctival rotation flap techniques (110 eyes in 110 patients) with a minimum follow-up of 12 months were reviewed. In this technique, a conjunctival flap is rotated to cover the bare sclera and suture-fixated with either 8–0 polyglactin (41 eyes) or 10–0 nylon (69 eyes). The recurrence rate was determined, and the two suture materials utilized were compared.

Results

The recurrence rate was 2.71% (3 cases in 110 eyes) when an anchored conjunctival rotation flap technique was used and patients were monitored for 26.40 ± 17.09 months. Interestingly, the recurrences were only observed in polyglactin-sutured eyes. No recurrence was detected in nylon-sutured eyes. No other complications were observed in either group.

Conclusions

The anchored conjunctival rotation flap technique for pterygium surgery has a relatively low recurrence rate. Nylon suture-fixation of the flap was found to be superior to polyglactin suture-fixation in preventing recurrence.

Electronic supplementary material

The online version of this article (10.1186/s12886-017-0587-z) contains supplementary material, which is available to authorized users.

The peroneus brevis flap in the treatment of bone infections of the lower limb

The Peroneus Brevis Flap is a described option for the soft tissue coverage and for small bone gap reconstruction in the lower third of the lower leg, where few other local flaps are available and reliable. We analysed retrospectively a case series of 11 consecutive patients whose age ranged from 31 to 87 years (mean 56), who underwent a reconstruction with a PB flap in the treatment of post-traumatic bone infections from October 2010 to February 2012. In our series, only one patient at a 3 year minimum follow-up showed recurrence of the bone infection and required further surgical treatment. Main complications were partial flap necrosis or overlying skin graft necrosis, but without the need of secondary surgery. In our experience, the PB flap is a reliable option for soft tissue coverage in the treatment of distal leg and ankle osteomyelitis.

A new modification of the Duckett technique for one-stage repairing urethral plate transected hypospadias: Another option for severe hypospadias?

OBJECTIVES

The study aimed to evaluate the new modification of the Duckett technique in decreasing the incidence of urethral strictures for urethral plate transected hypospadias and also explored its clinical application.

METHODS

Thirty-three patients (aged 7 months to 12 years, mean age 2.8 years) who underwent repair of primary hypospadias using the new one-stage urethroplasty were enrolled. Clinical data, including cosmetic and its complications, and uroflowmetry data were documented. Uroflowmetry data of 19 patients who underwent Duckett urethroplasty were used as a comparison.

RESULTS

The length of the urethral defect ranged from 2.5 to 5.0 cm. The postoperative follow-up was 14-30 months. Ten patients (30.3%) had fistulas; no patients had strictures or diverticula. All ten fistulas were small (<0.5 cm) and repaired with fistula repairing operation. The appearance of the penis remained satisfactory, and the meatus was located in the normal anatomic position. Among 17 patients who underwent uroflowmetry, all patients were bell-shaped or platforms, and Q _max was 7.37 ± 2.45 ml/s. Compared with 14 of 19 patients who underwent Duckett urethroplasty, the urethral function achieved with new one-stage urethroplasty was significantly better (p < 0.05).

CONCLUSIONS

The incidence of strictures was dramatically lowered in patients with proximal hypospadias. Small fistulas are common complications and can be repaired easily. Based on the uroflow pattern results, the quality of neourethra and function of it were better than Duckett urethroplasty. These preliminary results suggested that the modified procedure seems to be reliable and can be a suitable option for proximal hypospadias.

Pharyngeal flap damage caused by nasotracheal intubation in a patient who underwent palatoplasty and pharyngoplasty

Patients with cleft lip and palate (CLP) must undergo corrective surgeries during infancy and early childhood. Many patients with CLP undergo orthognathic surgery during their childhood for correction of skeletal asymmetries or pharyngoplasty with a pharyngeal flap to improve the quality of speech and velopharyngeal function. During orthognathic surgeries, nasotracheal intubation is performed under general anesthesia. In our case report, the patient had undergone palatoplasty and pharygoplasty previously. During the orthognathic surgery, a flexible fiberoptic bronchoscope-guided nasotracheal tube was inserted through the pharyngeal flap ostium; however, active bleeding occurred in the nasopharynx. Bleeding occurred because the flap was torn. After achieving hemostasis, the surgery was completed successfully. Thus, if a patient may show the potential for velopharyngeal port obstruction, nasotracheal intubation should be performed with utmost care.

Anatomical Correlation Between Nasal Vascularisation and the Design of the Endonasal Pedicle Flaps

Arteries that supply the nasal septum and the lateral nasal wall include vessels that originate from the external carotid artery and from the internal carotid artery. A variety of local endonasal pedicle flaps can be used in different anatomical areas for endoscopic skull base reconstruction. The main flaps are based on terminal branches of the sphenopalatine artery and on anterior ethmoidal artery. This study will describe the anatomy of these vessels and their relationship with the main flaps.

Rotational Flap to Enhance Buccal Gingival Thickness and Implant Emergence Profile in the Esthetic Zone: Two Cases Reports

OBJECTIVE

Many techniques have been developed to enhance the gingival thickness, gingival level and emergence profile around the implant in the esthetic zone.

INTRODUCTION

In this study, a buccal rotational flap was used to improve the implant site in the esthetic zone and increase gingival tissue thickness.

METHODS

Two cases involved the use of a rotational flap during second-stage implant surgery, one case involved the use of a temporary crown with a healing abutment, and another case involved the use of a healing abutment.

RESULT

The cases were followed up until the final crown was placed. The implant site was improved in 2 cases; the gingival thickness increased, the gingival level was enhanced and the emergence profile was developed.

CONCLUSION

Many factors affect the results of a rotational flap; some factors are surgical, while others are prosthetic, biological and anatomical.

A modified nasolabial flap for reconstruction of transfixing alar wing defects

Reconstruction of an entire alar wing is a frequently encountered reconstructive challenge in onco-dermatologic surgery. The aim of this technical note was to describe a surgical technique total for reconstruction of the alar wing, with a modified nasolabial flap with an inferior pedicle associated with a cartilaginous graft. This rapid procedure seems to be a well alternative for elderly people and patients who do not want a forehead flap. The aesthetic and functional outcomes of the donor and recipient sites were satisfactory.

Axial Pattern Flaps

Axial pattern flaps are based on a direct cutaneous artery and vein supplying a segment of skin. They provide a large, robust option for large wound closure. Many different axial pattern flaps have been described to provide options for closure of wounds located from the nose to the tail. All axial pattern flaps require good surgical technique and careful attention to detail while developing of the flap.

The Chicken Thigh Adductor Profundus Free Muscle Flap: A Novel Validated Non-Living Microsurgery Simulation Training Model

Background

Simulation training is becoming an increasingly important component of skills acquisition in surgical specialties, including Plastic Surgery. Non-living simulation models have an established place in Plastic Surgical microsurgery training, and support the principles of replacement, reduction and refinement of animal use. A more sophisticated version of the basic chicken thigh microsurgery model has been developed to include dissection of a type 1-muscle flap and is described and validated here.

Methods

A step-by-step dissection guide on how to perform the chicken thigh adductor profundus free muscle flap is demonstrated. Forty trainees performed the novel simulation muscle flap on the last day of a 5-day microsurgery course. Pre- and post-course microvascular anastomosis assessment, along with micro dissection and end product (anastomosis lapse index) assessment, demonstrated skills acquisition.

Results

The average time to dissect the flap by novice trainees was 82±24 minutes, by core trainees 90±24 minutes, and by higher trainees 64±21 minutes (P=0.013). There was a statistically significant difference in the time to complete the anastomosis between the three levels of training (P=0.001) and there was a significant decrease in the time taken to perform the anastomosis following course completion (P<0.001). Anastomosis lapse index scores improved for all cohorts with post-test average anastomosis lapse index score of 3±1.4 (P<0.001).

Conclusions

The novel chicken thigh adductor profundus free muscle flap model demonstrates face and construct validity for the introduction of the principles of free tissue transfer. The low cost, constant, and reproducible anatomy makes this simulation model a recommended addition to any microsurgical training curriculum.

A PM7 dynamic residue-ligand interactions energy landscape of the BACE1 inhibitory pathway by hydroxyethylamine compounds. Part I: The flap closure process

BACE1 is an enzyme of scientific interest because it participates in the progression of Alzheimer's disease. Hydroxyethylamines (HEAs) are a family of compounds which exhibit inhibitory activity toward BACE1 at a nanomolar level, favorable pharmacokinetic properties and oral bioavailability. The first step in the inhibition of BACE1 by HEAs consists of their entrance into the protease active site and the resultant conformational change in the protein, from Apo to closed form. These two conformations differ in the position of an antiparallel loop (called the flap) which covers the entrance to the catalytic site. For BACE1, closure of this flap is vital to its catalytic activity and to inhibition of the enzyme due to the new interactions thereby formed with the ligand. In the present study a dynamic energy landscape of residue-ligand interaction energies (ReLIE) measured for 112 amino acids in the BACE1 active site and its immediate vicinity during the closure of the flap induced by 8 HEAs of different inhibitory power is presented. A total of 6.272 million ReLIE calculations, based on the PM7 semiempirical method, provided a deep and quantitative view of the first step in the inhibition of the aspartyl protease. The information suggests that residues Asp93, Asp289, Thr292, Thr293, Asn294 and Arg296 are anchor points for the ligand, accounting for approximately 45% of the total protein-ligand interaction. Additionally, flap closure improved the BACE1-HEA interaction by around 25%. Furthermore, the inhibitory activity of HEAs could be related to the capacity of these ligands to form said anchor point interactions and maintain them over time: the lack of some of these anchor interactions delayed flap closure or impeded it completely, or even caused the flap to reopen. The methodology employed here could be used as a tool to evaluate future structural modifications which lead to improvements in the favorability and stability of BACE1-HEA ReLIEs, aiding in the design of better inhibitors.

Use of platelet-rich plasma (PRP) in microsurgery

Platelet-rich plasma (PRP) is currently used for its property to improve tissue regeneration and wound healing. Platelet derived growth factors are involved in tissue regeneration and new vessels formation that could improve a free flap survival. Nevertheless to validate the use of regenerative medicine in microsurgery further large and robust human clinical trials are needed.