Charles Yuen Yung Loh

Reviewing immunosuppressive regimens in animal models for vascularized composite allotransplantation

The development of vascularized composite allotransplantation (VCA) and its clinical need has led to the need for more animal models to study and perform the research required to further this specialty in terms of functional recovery and immunomodulatory improvements. Much of the animal models are reported in individual series in the literature but there has not been a review as such of these models. Here we present a compilation of the animal models reported in the literature thus far in VCA. A comprehensive review of the literature was performed for any studies which involved the use of animal models in various aspects of VCA research. The models were organized according to the type of VCA transplant, whether they were orthotopic or heterotopic, immunosuppressive regimen each study used and investigation purpose. Twenty-one facial transplant models were reported, 3 abdominal wall transplants, 4 penile transplantations, 21 uterus transplantations, 12 hindlimb transplantations and 4 myocutaneous flap transplantation animal models were reported. Primates, swine, rats, mice, rabbits, sheep and dog animal models in VCA were also reported. The most used immunosuppressive drugs are calcineurin inhibitor such as cyclosporin A and tacrolimus in these VCA animal models. They can significantly suppress lymphocyte function by blocking the phosphatase activity of calcineurin of lymphocytes. They are sometimes used combined with mycophenolate mofetil or steroids or antilymphocyte serum. The review of existing animal models will allow further research to be focused in other areas of VCA where there is a current paucity of literature. The immunosuppressive regimens used in each animal model can also be reviewed to determine which regimen works in which type of animal model which will save time and resources for future research.

Frontal Branch of the Superficial Temporal Artery Advancement Flap with Burrow’s Triangles Excision for Temporal Defect Reconstruction

Reconstruction of large defects in the temporal region can be difficult after skin cancer excision. Local reconstructive options under local anaesthesia can be limited, and skin grafting is a common method of reconstructing the defect. We describe a simple advancement flap based on the frontal branch of the superficial temporal artery (STA) with excision of burrow triangles in order to reconstruct such a defect. A biopsy-proven undifferentiated squamous cell carcinoma lesion was excised with a 5-mm margin from the right temple. The excision was taken to the temporalis fascia under local anaesthetic field block. After haemostasis, two parallel incisions were made all the way to the tragal area in the path of the STA frontal branch. The defect after excision was 4.7 9 4 cm and the flap measured 8 cm long by 5 cm in width. The flap was taken at the fascial level and above the superficial muscular aponeurotic system (SMAS) level in the face to avoid any damage to the facial nerve. The frontal branch of the facial nerve was not encountered during the dissection and was preserved. The burrow triangles at the base of the flap are excised and tidied up and that allowed the flap to be advanced for 4 cm and was inset with dissolvable sutures (Fig. 1). Local flaps allow primary healing of the wound defect which especially in the elderly and can minimize the risk of wound complications and infections that are commonly associated with a skin graft. This advancement flap also has the advantage of reconstructing the hair-bearing areas after resection. The frontal branch of the STA is relatively consistent with an accompanying vein [1, 2]. Not visualizing the vessels but including all the subcutaneous flap and preserving the wide base of the flap aids in venous drainage. Performing hydrodissection with local anaesthetic solution also helps in delineating the dissection plane in our hands. A simple advancement flap in the STA frontal branch with excision of burrow triangles as seen allows the coverage of a 4.7 9 4 cm defect as seen if taken all the way to the front of the tragus. The design of the skin paddle itself is key here with minimal dissection of the base of the flap to decrease inadvertent injury to the named blood vessel or facial nerves. It also incorporates a wide base

A challenging case of calcific myonecrosis of tibialis anterior and hallucis longus muscles with a chronic discharging wound

The occurrence of calcific myonecrosis of the anterior compartment of the leg is rare. Common risk factors include a history of trauma, although little is known about the exact pathophysiology, latency period or triggering factors resulting in disease progression. Macroscopically, it begins with a single muscle being replaced by a fusiform calcified mass, which progresses peripherally.

Double Z plasty advancement flaps for closure of large defects on the forearm

Dear Editors, The application of Z plasties in wound closure is not uncommon when attempting to break up a direction of a scar and re-orientate it in a better resting line of skin tension. However, its use in the design of advancement flaps for closing large defects is often not really known. We present a simple yet effective method of utilising double Z plasties in the forearm for closure of a wound defect which would otherwise be too large to close directly. Z plasties recruit tissue and transpose them in a different direction to allow a tension free closure or advancement of tissues in a particular direction. In the case illustrated below (Figure 1), the defect distally on the forearm would be too large to close directly, especially in a cylindrical type structure such as the forearm. The design of the double Z plasty advancement flaps as seen allows for a tension free closure of not only the distal defect, but also the donor area. The design of the Z plasty arms are such that they are at 45 to allow a gain of 75% in length without compromising the donor site closure. The limbs should be designed of equal length to the width of the defect in planning such a local flap closure. Closure of the defect should also be performed in layers with deep and superficial sutures. The final result avoids the need for a skin graft or contour defect as a local flap reconstruction has been performed. This can be performed under tourniquet control in the limb to facilitate dissection. Perforators to each flap can be divided as the base in broad and vascular supply will be adequate in these flaps. It is only when perforators are divided that the double opposing flaps can be advanced without tension. This simple method of closing a defect on the forearm can be applied under local anaesthetic and will not require a skin graft or result in a contour defect.

The modified Souquet flap for reconstruction of fingertip amputations

Dear Editors, Fingertip amputation is the most common type of amputation of the upper limb, and as such, a great deal of surgical management options exists. The aims are to maintain length where possible, restore sensation, and provide stable soft tissue cover that allows patients an early return to their everyday activities. The Hueston and Souquet flaps can be used to cover fingertip amputation. They are similar in that they are rectangular flaps, which are advanced and rotated to cover volar defects. In the Hueston flap, 1 edge is dissected superficial to the neurovascular bundle, giving it a greater degree of mobility and advancement compared with the Souquet technique. The latter is restricted due to tethering to the neurovascular bundle, but the trade-off of mobility allows a greater potential for a sensate tip, previously reported at 77% and 92% of cases, respectively. Furthermore, Lloyd and Sammut described a modification of the Souquet technique by extending the incision proximally on the midlateral line of the leading edge to the level of the proximal interphalangeal joint. Further dissection and mobilisation of the neurovascular bundle allowed greater mobility without giving up sensibility of the glabrous skin. A 43-year-old right hand-dominant male sustained a chainsaw transverse fingertip amputation at Allen Zone 2/Tamai zone 1 of the left middle finger (Figure 1A,B). Soft tissue cover with glabrous skin is ideal to ensure quick healing time and a sensate tip that can replicate the pulp of a

Using intestinal segments during secondary salvage procedures after failed reconstructions of the cervical oesophagus

OBJECTIVESnThe free anterolateral thigh (ALT) flap is commonly used for the reconstruction of the cervical oesophagus with satisfactory results. Its convenience and popularity make it a popular flap for reconstructive surgeons. The use of intestinal flaps, however, carries a higher level of technical difficulty and is normally performed as a primary reconstructive procedure. This report investigates the feasibility of intestinal flaps for the reconstruction of the cervical oesophagus and strategies to optimize its success when used as a secondary flap after primary ALT flap failure.nnnMETHODSnWe retrospectively reviewed 22 patients (age 39-72u2009years) who were men, between April 2013 and January 2015, with intestinal segments (free and pedicled ileocolon, jejunal and colon flaps) that were used secondarily to salvage failed primary free ALT flap reconstructions after hypopharyngeal cancer resection. Ten patients presented with leakage and 2 with tracheo-oesophageal fistulae as complications from the primary flap failure.nnnRESULTSnOral intake commenced around 1-month postoperatively. One case of flap failure was observed. The majority had no major postoperative complications. Patients were followed up (6-27u2009months), and 21 cases of a secondary intestinal flap were successful with the restoration of oesophageal continuity and oral intake.nnnCONCLUSIONSnIntestinal flaps, free or pedicled, can be used secondarily after failed ALT flap reconstructions with minimal complications or morbidity. Intestinal flaps successfully allow restoration of gastrointestinal continuity with early commencement of oral intake and swallowing function.

Tips and tricks for getting more out of your delayed primary repair of ruptured flexor pollicis longus tendon

Primary tendon repairs are often difficult in patients with delayed presentation. Tendons are contracted and shortened with extensive scarring occurring along the path of the tendon. Pulleys and the wound bed can be filled with granulation tissue which obstructs the passage of the tendon. Many of such patients would then be treated with a two stage tendon reconstruction, which involves the insertion of a silicone rod for pseudosheath formation[1] before tendon grafting at a second stage. This however, would set the patient back for roughly six months, especially involving multiple visits to physiotherapy and being off work. We would like to describe several tips and tricks in our armamentarium and illustrate these using a case we recently encountered [Figure 1].

The exquisitely painful fingertip - subungual glomus tumours: Letter to the Editor

While most painful fingertips have a distinct causal history and/or associated symptoms, some can leave the practitioner at a loss during diagnosis. We present a rare differential that often has an indistinct history, subtle clinical signs and is commonly misdiagnosed, with average diagnosis time reported as 7 years (1). A 25-year-old patient presented with a several-year history of a gradually increasingly painful fingertip, just beneath her nail plate. There was no history of trauma or precipitating event she could recollect. She had been assessed by several practitioners over the years with normal radiology and ineffective neuromodulation, and analgesics offered little effect. On examination, she had a minimal area of slight blue discolouration under her nail plate, which elicited exquisite pain on palpation. This was diagnosed clinically as a subungual glomus tumour based on the symptom of exquisite pain in the fingertip without causal history and the subtle colour discolouration. Treatment was surgical excision under a digital nerve block with removal of the overlying nail plate. The lesion was characterised as a spot directly beneath the nail plate (Figure 1A), with a leash of proximal feeding vessels (Figure 1B). Excision was performed and the resulting defect closed directly (Figure 1C). Histology subsequently confirmed the clinical diagnosis of a glomus tumour, and on postoperative review, she was pain free. Glomus tumours were first described by Wood in 1812, with subsequent histological characterisation by Masson in 1924 (2,3). They are rare, typically benign tumours that arise from the neuromyoarterial structure of the glomus body, a structure believed to serve a thermoregulatory purpose (4). They account for 1–4⋅5% of hand tumours and are more common in women (1,5). Although within the hand, the most common site being subungual, glomus tumours may also be found under the