High-Fidelity Perforator Visualization for Cadaver Dissection in Surgical Training.

In the first half of the third century B.C., Herophilus and Erasistratus performed the first systematic dissection of the human body. For subsequent centuries, these cadaveric dissections were key to the advancement of anatomical knowledge and surgical techniques. To this day, despite various instructional methods, cadaver dissection remained the best way for surgical training. To improve the quality of education and research through cadaveric dissection, our institution has developed a unique method of perforator-preserving cadaver injection, allowing us to achieve high-fidelity perforator visualization for dissection studies, at low cost and high efficacy. Ten full body cadavers were sectioned through the base of neck, bilateral shoulder, and hip joints. The key was to dissect multiple perfusing arteries and draining veins for each section, to increase "capture" of vascular territories. The vessels were carefully flushed, insufflated, and then filled with latex dye. Our injection dye comprised of liquid latex, formalin, and acrylic paint in the ratio of 1:2:1. Different endpoints were used to assess adequacy of injection, such as reconstitution of eyeball volume, skin turgor, visible dye in subcutaneous veins, and seepage of dye through stab incisions in digital pulps. Dissections demonstrated the effectiveness of the dye, outlining even the small osseous perforators of the medial femoral condyle flap and subconjunctival plexuses. Our technique emphasized atraumatic preparation, recreation of luminal space through insufflation, and finally careful injection of latex dye with adequate curing. This has allowed high-fidelity perforator visualization for dissection studies.

Infection of a venous port - beware of the Mycobacterium.

An 84-year-old female with metastatic left breast cancer underwent a venous port insertion for chemotherapy. The port was inserted using standard techniques with image guidance under local anesthesia. She presented after 36 days with evidence of infection. A limited bedside ultrasound demonstrated free fluid surrounding the port. The port was subsequently removed the same day, at which time pus was expressed from the subcutaneous pocket. The culture from the pus grew Mycobacterium abscessus. She required removal of the port and wound debridement, wound dressings and a prolonged course of antibiotics. Mycobacterium abscessus is a group of rapidly growing, multidrug-resistant, non-tuberculous mycobacteria that are also relatively resistant to standard skin disinfectants. In recent years, this organism has been increasingly reported as the culprit in post-operative or post-procedural infections. Treatment is challenging due to multidrug resistance, and requires an extensive course of intravenous antimicrobial and macrolide-based combination therapy followed by oral antimicrobial therapy. Early treatment is essential as progression may result in disseminated infection. We discuss the peri-operative and post-operative care required in preventing and treating infection with this organism.

Maximizing Micrograft Take in Extensive Back Burns.

Extensive burns involving the back pose unique challenges. Offloading in the prone position is not possible with concomitant deep facial and neck burns. We describe our experience in maximizing graft take in a patient who had extensive back burns with concomitant anterior body burns. The two main goals in graft fixation for extensive back wounds are mechanical stabilization of micrografts to reduce shearing and prevention of water logging from exudates or bleeding to optimize contact with wound bed. Guided by the stages of wound healing, graft take, and burn care, we describe three stages of postoperative negative pressure wound therapy (NPWT) in a patient with 54% TBSA burns treated with micrografting. After complete excision of the deep dermal burns of the entire back, the wounds were covered with micrograft-allograft composites. In phase I, days 1 to 3, conventional topical negative pressure dressing with a thin sponge was applied and a leak-proof seal was achieved with gel sealant and high tack adhesive drapes. In phase II, days 4 to 5, foam dressings with topical negative pressure were applied, but with a less stringent seal, supported by wall suction. In phase III, the selective removal of allografts was initiated to facilitate expansion of micrografts. Negative pressure was continued for another 2 weeks at the most dependent site to prevent wound maceration from exudates. Micrograft take was optimized with the patient in the supine/semirecumbent position. The back wounds healed completely between 60 and 70 days without repeat micrografting. Since prone positioning was not possible in this patient, clearance of exudates and maintenance of micrograft contact with the wound bed using this technique proved successful.

Strategies for a successful hepatic artery anastomosis in liver transplantation: A review of 51 cases.

INTRODUCTION: Hepatic artery reconstruction is a critical aspect of liver transplantation. The microsurgeon faces several challenges when reconstructing the hepatic artery-the donor hepatic artery stalk is short and often a poor match for the usually hypertrophic recipient vessels. Previous inflammation impedes vessel dissection, and recipient vessels have a tendency to delaminate with manipulation. We review 51 consecutive liver transplantations to highlight these problems and propose strategies for a successful reconstruction of the hepatic artery. METHODS: A prospective study involving all adult patients undergoing liver transplantation at the Singapore General Hospital from January 2015 to December 2018 was undertaken. All hepatic artery anastomoses were performed by 2 microsurgeons at 10x magnification. Patients were started on a standard immunosuppressive regimen. Postoperative ultrasound scans on days 1, 3, 5, 7, 9 and 14 were used to confirm arterial patency. RESULTS: There were 51 patients who underwent liver transplantation during the study period. Of this number, 31 patients received deceased donor grafts and 20 received living donor grafts. A total of 61 anastomoses were performed (5 dual anastomosis, 4 radial artery interposition grafts) with 1 case of hepatic artery thrombosis that was successfully salvaged. The mean (range) postoperative resistive index and hepatic artery peak systolic velocity were 0.69 (0.68-0.69) and 1.0m/s (0.88-1.10m/s), respectively. CONCLUSION: Hepatic artery thrombosis after liver transplantation is poorly tolerated. The challenges of hepatic artery reconstruction in liver transplantation are related to vessel quality and length. The use of microsurgical technique, appropriate recipient vessel selection, minimisation of vessel manipulation with modified instruments, variation in anastomosis techniques, and use of radial artery interpositional grafts are useful strategies to maximise the chances of success.

Use of the extended pectoralis major myocutaneous flap as a wrap-around for mediastinal tracheal repair.

Persistent tracheoesophageal fistulas requiring flap repair of the trachea in the mediastinum are uncommon. A 44-year-old man developed a 5 cm x 2 cm persistent posterior tracheal defect after failed tracheo-esophageal fistula repair. The defect was patch repaired using the de-epithelialized skin paddle of an extended pectoralis major flap tunneled into the mediastinum. The use of cross-field ventilation, second rib removal and an anterior tracheostomy slit were crucial for posterior tracheal repair. No major complication occurred. The patch repair with the de-epithelialized skin paddle of pectoralis major flap mucosalized in 2 weeks and the patient was discharged one month postoperatively. The extended skin paddle of the pectoralis major flap was a useful method for tracheal wrap-around reconstruction.

Use of the Descending Branch of the Lateral Circumflex Femoral Artery as an Arterial Graft in Living Donor Liver Transplant.

BACKGROUND: Reconstructing the hepatic artery in living donor liver transplantation presents the challenges of a short and small donor vessel stump, which is compounded by poor surgical access for microsurgical anastomosis. Arterial interpositional grafts (eg, the radial artery) have been used to overcome these problems. The purpose of this presentation is to describe the use of the descending branch of the lateral circumflex femoral artery (DLCFA) as an alternative when the patient has had an abnormal Allen's test precluding the use of the radial artery or if a Y-graft is needed. METHODS: The DLCFA resides in the septum between the rectus femoris and vastus lateralis muscles. A linear incision made over the proximal third of this septum exposed the avascular plane in which the vessel resides. A graft exceeding 10 cm could be harvested with diameters ranging between ≤2 and 7 mm. There were several muscular branches emanating from the profunda femoris artery system that could be dissected to the required length for a Y-shaped graft. Three cases of living donor liver transplantation using the DLCFA (straight and Y grafts) are described. RESULTS: After DLCFA interpositional grafting, all patients had normal resistive indices on duplex ultrasonography of the intrahepatic arterial system. Follow-up of the 3 patients was between 2 and 6 months. There was no donor site morbidity. CONCLUSIONS: The DLCFA graft was a useful arterial graft for hepatic artery reconstruction. It was easily harvested with minimal donor site morbidity.

Customized Two-Dimensional Computed Tomography-Guided Preoperative Pectus Bar Shaping.

INTRODUCTION: Successful minimally invasive repair of pectus excavatum relies on a pectus bar that closely conforms to the desired shape of the sternum and ribs to produce optimal elevation and remodeling. However, the present method of empirical intraoperative bar shaping is tedious and risks trauma to surrounding structures. To overcome this, we devised a technique using a life-sized computed tomography (CT) printout of the patient's chest wall to guide preoperative bar bending. METHODS: A 5-cm-wide polymethylmethacrylate block placed on the sternum as the patient underwent chest CT was used as a marker to guide scaling of an axial screenshot of the patient's chest to life-size. This life-size image was printed and the planned correction of the patient's chest wall was traced onto it. The pectus bar was bent according to this template. Patient demographics, Haller index, surgical indications, operative technique, complications, aesthetic and functional improvements, and overall satisfaction were assessed. RESULTS: Thirty patients (4 women) underwent primary minimally invasive repair of pectus excavatum with a single pectus bar shaped preoperatively over an 8-year period. The average age and Haller index was 20.6 years and 5.4, respectively. The mean operative time was 66.4 minutes. Satisfactory sternal elevation was attained with a single attempt at bar insertion in all cases. Two patients had pneumothoraxes that resolved without intervention. The mean follow-up period was 50.1 months. There were no cases of bar migration or recurrence of deformity after bar removal. On a 5-point Likert scale, all patients indicated an improvement in aesthetic appearance (4.6), and patients with physical symptoms (10) reported an improvement in function (4.4). The overall satisfaction score was 4.7. CONCLUSIONS: This technique of CT-guided preoperative pectus bar shaping is straightforward, eliminates the need for intraoperative revisions to bar shape, and achieves effective correction of the pectus excavatum deformity. All patients were satisfied with the aesthetic, functional, and overall outcomes.

Early Experience with Biobranetm for Definitive Coverage of Tangentially Excised Partial-Thickness Thermal Burns.

BiobraneTM is a popular biosynthetic semi-permeable skin substitute conventionally applied onto non-excised partial thickness burn wounds to facilitate healing. The use of BiobraneTM for definitive coverage after excision of partial-thickness thermal burns has not been reported. We highlighted our experience of immediate BiobraneTM application for definitive coverage of tangentially-excised partial thickness thermal burn wounds in four patients. This technique is safe and efficient, minimizes painful and costly dressing changes, avoids the complications associated with autologous skin grafting, and eliminates the unpredictability of burns wound conversion. We believe this method expands the indications for BiobraneTM usage, accelerates wound healing, and provides better aesthetic outcomes.

Anatomical Study of the Medialis Pedis Flap and its clinical applications in Asian Singaporean Patients.

PURPOSE: The purpose of this study was to revisit the medial plantar artery's anatomy and study its distribution for raising the medialis pedis flap. Several investigators have reported their clinical experience with the use of this flap for reconstruction of soft tissue defects of the hand. However, many have reported difficulty raising the flap due to variations in its arterial anatomy and the confusion that exists with respect to the nomenclature in our literature. METHODS: This study was divided into 2 parts: an anatomic study and clinical application. In the anatomic study, 12 cadaveric feet specimens from 6 patients were injected with latex and barium-gelatin injections and the medial branch of the deep division of the medial plantar artery distribution was studied. We then described the use of a medialis pedis flap in four clinical cases to cover defects of the digits. RESULTS: The anatomic study revealed that the average pedicle length of the deep division of the medial plantar artery was 1.94cm. In the four illustrative clinical cases where the flap was used, the average flap size was 4.5 × 3.75cm. Donor sites were either closed primarily or with skin grafts. The vessels used for this flap were the medial branch of the deep division of the medial plantar artery and venae commitantes, or subcutaneous veins which provided the superficial drainage. All flaps were successful without any significant complications. The study is novel in that it describes the anatomic variability of length of the medial branch of the deep division of the medial plantar artery that exits in nature. CONCLUSIONS: This paper describes the medial branch of the deep division of the medial plantar artery and the anatomic variations that exist in the raising of the medialis pedis flap. We have shown how a medialis pedis flap is an ideal option for reconstructing soft tissue defects of the hand because of its texture, bulkiness and pliability in the context of like for like reconstruction.

Hepatic Artery Reconstruction in Living Donor Liver Transplantation With the Radial Artery Interpositional Graft.

INTRODUCTION: Reconstitution of hepatic artery inflow is essential for a successful liver transplantation. Living donor transplantation presents additional challenges in the form of a short and small donor vessel stump, exacerbating the poor surgical access for microsurgery. Few reports have described the use of the radial artery as an interposition graft in liver transplantation; we present a series of 6 cases and discuss the technical merits of this procedure. METHODS: Retrospective review of consecutive patients undergoing living donor liver transplantation from December 2015 to December 2019 was performed. Demographics, operative details, and postoperative outcomes were reviewed. RESULTS: Twenty-two patients underwent living donor liver transplantation. Radial artery interposition grafting was used in 6 cases, including 1 salvage case for hepatic artery thrombosis. One patient developed hepatic artery stenosis (2 weeks postoperatively) that was conservatively managed. After radial artery grafting, all patients had normal resistive indices on duplex ultrasonography at up to 20 months postoperatively. The mean follow-up was 15.2 months. CONCLUSION: When faced with a significantly short vessel stump or caliber mismatch, radial artery interpositional grafting is a safe and useful technique for reducing tension and overcoming vessel size mismatch in hepatic artery reconstruction.

Coverage of anterior mediastinal tracheostomy with bipedicled anterolateral thigh flap.

BACKGROUND: Cancer defects requiring anterior mediastinal tracheostomy (AMT) are complex, often accompanied by tracheo-laryngeal and pharyngeal defects with exposure of the great vessels and mediastinal cavity. The trachea has to be mobilised and exteriorised as an end-tracheostome through the anterior chest. A well-vascularised flap that can resurface skin defects, obliterate dead space and allow maturation of a reliable anterior mediastinal tracheostome is required. We describe a modification of using a centrally fenestrated bipedicled chimeric anterolateral thigh flap (ALT) to address these challenges. METHODS: A free chimeric bipedicled ALT flap was designed. The skin defect was resurfaced by a vertically-oriented skin paddle. Two chimeric muscle components were used to partition the mediastinum and the great vessels of the neck from the tracheostome. The mediastinal trachea was mobilised and matured through a centrally-fenestrated opening in the flap. Layered fascial sutures were employed to minimize dehiscence. RESULTS/COMPLICATIONS: Two patients with AMT underwent the modified ALT. No major complications such as flap-tracheostomy dehiscence occurred. One patient had a small peripheral demarcation of the flap which required revision and secondary closure. CONCLUSION: The bipedicled design of the modified ALT flap provided robust blood supply to the central fenestration through dual perforators, avoiding flap-tracheostomy separation. The chimeric muscle components obliterate dead space and protect the great vessels of the neck and mediastinum. The thin pliable nature of the anterolateral thigh skin also allowed for tensionless inset of the trachea.

Surgical planning using facial fracture 3D models: The role of cyanoacrylate glue and miniplating for anatomical reduction.

BACKGROUND: In comminuted facial fractures, peri-operative use of 3D-printed life size models is increasingly a useful adjunct. It allows for preoperative surgical rehearsal and plate bending, to achieve anatomical reduction with reduced operative time and cost. One problem encountered is difficulty contouring the fixation plate whilst maintaining the relative spatial orientation of comminuted fragments. This paper shares an effective method of overcoming this problem. METHODS: All comminuted facial fracture patients underwent counselling for 3D printing. Pre-printing thresholding and segmentation of each fragment (as directed by the surgeon) were done by the radiologist and the engineering team, using the multi-slice CT Face DICOM data. Life-size 3D-resin models of the fractures were printed. Fast-acting medium consistency cyanoacrylate glue (Zap-A-GapⓇ) and miniplates were used to assemble the printed model segments in 'anatomic reduction'. Aerosolized alcohol accelerator facilitated immediate glue curing, providing a stable model. The plates were adapted over this restored neonative 3D construct with bending inserts, sterilized and used intraoperatively. The 3D model was used to guide the operative sequence. Intraoperative CT was used in select cases to confirm anatomic reduction. RESULTS/COMPLICATIONS: All patients (n = 5) had comminuted fractures in at least one of the bony units (mandible, maxilla or orbits) and one was a pan-facial fracture case. 3D printed models aided fracture reduction and fixation, whilst avoiding the guesswork in ascertaining the contour of the mandibular arch. In addition, the pre-contoured mandible plates restored premorbid occlusion and projection, without the need for long-term archbars in all cases. Operative time was estimated to be reduced by 0.5-1 h. Resident teaching was enhanced by this approach. CONCLUSION: The application of medium consistency fast-acting cyanoacrylate glue and miniplates facilitated the creation of the premorbid facial skeletal model and allowed pre-bending of the plates, thus saving operative time and cost.

Impact of Microsurgical Anastomosis of Hepatic Artery on Arterial Complications and Survival Outcomes After Liver Transplantation.

Hepatic artery (HA) complications after liver transplant (LT) can lead to biliary complications, graft failure, and mortality. Although microsurgery has been established to improve anastomotic outcomes, it prolongs surgical time and has not reached widespread adoption at all transplant centers. We investigated the incidences of arterial, biliary complications and outcomes after using microsurgery to anastomose HA during LT. Retrospective cohort of consecutive LT performed from 2006 to 2018 was reviewed for operative details and postoperative outcomes. Cox-regression models were used to investigate the relationship between variables and outcomes. Eighty (62.5%) LTs (Group 1) were performed without and compared with 48 (Group 2) with microsurgical anastomosis of HA. Both groups were comparable in terms of arterial and biliary anastomoses performed. Incidence of early HA thrombosis was similar (6.2% vs 2.1%, P = .28). Group 2 had lower incidence of short- and long-term arterial complications, especially amongst living donor liver transplantations (LDLT) (5.3% vs 35.0%, P = .022). On multivariate analysis, microsurgery was associated with lower risk (hazard ratio [HR] 0.09, 95% confidence interval [CI] 0.01-0.71) of, and LDLT had higher risk (HR 4.23, 95% CI 1.46-12.27) of arterial complications. Biliary complications were associated with LDLT (HR 3.91, 95% CI 1.30-11.71) and dual biliary anastomoses (HR 5.26, 95% CI 1.15-24.08) but not with occurrence of HA complications. Worse patient survival was associated with the occurrence of any HA complication (HR 4.11, 95% CI 1.78-9.48). Hepatic arterial complications can be reduced using microsurgical techniques for the anastomosis, resulting in improved patient survival outcomes after liver transplantation.

Current operative management and therapeutic algorithm of lymphedema in the lower extremities.

Lymphedema is defined as the abnormal accumulation of interstitial fluid in subcutaneous tissues resulting from cancer, cancer treatment (surgery and/or radiotherapy), infection, inflammatory disorders, obesity, and hereditary syndromes. Surgical management of lymphedema can be broadly classified into two categories, reductive surgical techniques such as direct excision, suction assisted protein lipectomy (SAPL) or radical reduction with perforator preservation (RRPP); and physiological surgical procedures such as lymphaticovenous anastomosis (LVA) and vascularised lymph node transfer (VLNT). These techniques and their various combinations were evaluated. The results revealed patients with reversible lymphedema (ISL stage I, mild severity) benefit most from physiological procedures (LVA or VLNT) which can reduce the chance of disease progression to the chronic, solid phase. Reductive techniques such as SAPL, RPPP, or direct excision procedures should be reserved for patients with advanced - severe lymphedema (ISL stages II and especially stage III) as the surgical treatment of choice. In this study, current literature on the surgical treatment of lower extremity lymphedema is reviewed and discussed in conjunction with authors' clinical experiences. An algorithm is presented, based on clinical evidence and experience which aims to provide a structured approach to managing lower limb lymphedema.

The use of negative-pressure wound therapy over a cultured epithelial autograft for full-thickness wounds secondary to purpura fulminans in an infant.

Purpura fulminans is a serious condition that can result in severe morbidity in the pediatric population. Although autologous skin grafts remain the gold standard for the coverage of partial- to full-thickness wounds, they have several limitations in pediatric patients, including the lack of planar donor sites, the risk of hemodynamic instability, and the limited graft thickness. In Singapore, an in-house skin culture laboratory has been available since 2005 for the use of cultured epithelial autografts (CEAs), especially in burn wounds. However, due to the fragility of CEAs, negative-pressure wound therapy (NPWT) dressings have been rarely used with CEAs. With several modifications, we report a successful case of NPWT applied over a CEA in an infant who sustained 30% total body surface area full-thickness wounds over the anterior abdomen, flank, and upper thigh secondary to purpura fulminans. We also describe the advantages of using NPWT dressing over a CEA, particularly in pediatric patients.

Evaluating the feasibility of a novel Marking Breast Oncoplastic Surgery Simulator (MBOSS) as a training tool for marking: a randomised trial.

BACKGROUND: Currently, volunteers and/or anatomical models are used for teaching oncoplastic surgery marking. However, as the breast is an intimate organ, recruiting volunteers is difficult, and the available droopy breast models have limitations. We evaluated the feasibility of a novel Marking Breast Oncoplastic Surgery Simulator (MBOSS) for the teaching of marking. METHODS: Breast/plastic surgeons/trainees, grouped according to their oncoplastic experience, were randomized to MBOSS or volunteer. All had a pre-test evaluation prior to receiving hands-on training in inverted T mammoplasty marking in their randomized group, followed by an assessment of their marking skills, by an examiner blinded to their group assignment. All participants then underwent post-test and course evaluations, and those who used MBOSS for training, also evaluated MBOSS realism. Learning outcomes between the two groups were compared using the Kirkpatrick educational model. RESULTS: Forty participants were enrolled. Demographics, baseline oncoplastic experience and pre-test results were comparable between the MBOSS and volunteer groups. For Kirkpatrick level 1 satisfaction outcomes, the two groups did not differ significantly. For level 2 knowledge assessment, MBOSS post-test scores were significantly higher (P=0.0471). For level 3 skill application and level 4 organizational impact evaluated 6 months post course, there were no significant differences between the groups. Although MBOSS may not mimic the breast completely, 95% of MBOSS-trained participants rated MBOSS as a good training tool and 85% would use MBOSS instead of a volunteer. CONCLUSIONS: MBOSS learning outcomes are comparable to outcomes using volunteers, making MBOSS an alternative for teaching oncoplastic surgery marking.

Shaping of the abdominal flap in breast reconstruction: The coning technique in muscle sparing TRAM.

In the setting of autologous breast reconstruction, achieving an aesthetic outcome through shaping of the flap is of the upmost importance. We describe the abdominal flap folding technique of 'coning' and the indications. We define 'coning' as the technique of folding the abdominal flap in a circular fashion to create a conical breast mound, with the line of fusion forming a pillar of tissue for structural integrity. A retrospective study of 34 patients undergoing unilateral muscle-sparing TRAM flap was performed. Of these patients, the majority (79.4%) underwent immediate reconstruction, with the thoracodorsal vessels largely acting as the recipients (94.1%). Three (8.8%) patients were noted to have a contour defect secondary to incomplete folding of the flap. Two (5.9%) patients had partial skin envelope necrosis. One patient had 50% flap loss, requiring return to theatre for excision. In conclusion, coning was used exclusively in the muscle-sparing TRAM flap. This cuff of muscle protected the pedicle during folding through cushioning the perforators at their most vulnerable points. This technique allowed for muscle cuff harvest whilst minimising anterior sheath sacrifice. Coning achieved long-term maintenance of shape, volume and projection.

The Unresolved Pathophysiology of Lymphedema.

Lymphedema is the clinical manifestation of impaired lymphatic transport. It remains an under-recognized and under-documented clinical condition that still lacks a cure. Despite the substantial advances in the understanding of lymphatic vessel biology and function in the past two decades, there are still unsolved questions regarding the pathophysiology of lymphedema, especially in humans. As a consequence of impaired lymphatic drainage, proteins and lipids accumulate in the interstitial space, causing the regional tissue to undergo extensive and progressive architectural changes, including adipose tissue deposition and fibrosis. These changes are also associated with inflammation. However, the temporal sequence of these events, the relationship between these events, and their interplay during the progression are not clearly understood. Here, we review our current knowledge on the pathophysiology of lymphedema derived from human and animal studies. We also discuss the possible cellular and molecular mechanisms involved in adipose tissue and collagen accumulation during lymphedema. We suggest that more studies should be dedicated to enhancing our understanding of the human pathophysiology of lymphedema to pave the way for new diagnostic and therapeutic avenues for this condition.