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Achieving primary closure on the proximal third of the tail after 4 cm mass removal in a dog

January 5, 2020

Florin Cristian Delureanu

DVM, MRCVS

December 2019

Abstract

Defects located on the tail are challenging due to lack of skin. Second intention healing, skin grafts or random local flaps can be used as a treatment in this particular area. Primary closure can be used when small defects are present but risk of dehiscence and vascular compromise is very increased due to tension and tourniquet effect. In cats was described a perineal axial pattern flap used for covering a defect located on the proximal third of the tail. Also a “spiral closure technique” can be used to close small to medium size defects on the tail. The use of the advancement flap is usually the first choice in approaching the closure of defects if they can not be closed by undermining and suturing. This article illustrates the usage of advancement flap from the base of the tail for closing the surgical defect left after excision of a tumor located on the dorsal proximal third of the tail in a dog. No complications were noted after surgery and the tail maintained the normal function.

Case report

A 5 years old female neutered cross breed dog was admitted for assessment of a lump located on the tail. The owner was not sure for how long time the lump was in that place and how fast developed, was just recently observed on the tail.

On general examination no abnormalities were detected. A 4 cm mass was identified on the dorsal aspect of the mid proximal third of the tail. The mass had round shape, located under the skin and well attached to the coccygeus muscle. On palpation, local temperature was normal, elastic-firm consistency, without local pain. No other abnormalities were detected. Fine needle aspirate was recommended and performed before surgery.

Cytologic interpretation: marked pyogranulomatous inflammation, epithelial proliferation, neoplasia probable and evidence of mineralization.

Surgical approach and suture technique

Surgical site was aseptically prepared and the patient was placed on the table in ventral recumbency. Before starting the procedure, another evaluation of the mass in relation to the skin located on sacro-coccygeal area but also with the skin which surrounds the mass was done. Before incision, the skin mobility was checked. In physiological position a small skin fold was observed cranially to the lump (Fig.1).

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Figure 1. Preoperative appearance of the sacrococcygeal area after surgical site preparation. The tumor have a spheric shape, is located in the proximal third area of the tail-dorsal aspect and have a wide base of implantation. At the base of the tail a small fold can be observed

A circular incision was performed 3mm distance from the mass. No.10 scalpel blade was used to create the skin incision and the dissection until the muscle was done with Metzenbaum scissors.

A thin capsule that surrounds the mass was discovered at the junction between it and the coccygeal muscle. At that point the dissection was performed with the scalpel blade until the end. Care was taken to avoid the major vassels of the tail( Fig 2, Aand B)

Figure 2. Intraoperative view of the tail. (A) Right lateral side before tumor excision and (B) left lateral side after full excision hightlights the intact lateral coccygeal veins (yellow and black arrows).

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Fig 2

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Fig 2

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Figure 3. Transverse section at the level of caudal vertebrae illustrates distribution of the muscles

The tail movements are coordinated by 6 pairs of muscles (12 muscles in total) that are distributed concentrically over the coccygeal vertebrae (Fig.3).

The vascular supply of the tail is composed by 2 lateral caudal veins and arteries located

on lateral sides and the median caudal artery and vein. In this case both caudal lateral veins were preserved. Minimal bleeding was present and the small blood vassels were ligated with 3/0 PGA. Two parallel lines extended from the proximal border of

the defect to the base of the tail were made in the skin deep to the muscle. Meticulous dissection of the skin was performed with Metzenbaum scissors until the fold located at the base of the tail. The flap was elevated and advanced distally to cover the defect

(Fig.4 A). The flap managed to cover ¾ of the defect without tension. Undermining of the skin located on the distal border was attempted to obtain the mobility that can help to cover the ¼ of the defect but faild. To obtain the maximum coverage, walking sutures were used to further advance the flap. The first bite went deep into the dermis and the second bite in the tendinous portion of the m. sacrocaudalis dorsalis lateralis (sacrococcygeus dorsalis lateralis).Few walking sutures were placed so that the tension is equally distributed (Fig. 4B).

Figure 4. Undermining and elevation of the skin flap. (A) Stay sutured were placed on the flap corners (yellow arrows) to manipulate the skin; (B) Closer wiev of the first walking suture. First bite (blue arrow) is inserted deep in the dermis and the second bite is inserted in the tendons of m. sacrocaudalis dorsalis lateralis (black arrow).

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Fig 4

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Fig 4

Nor following this procedure the primary defect has not been fully covered. In the end, horizontal mattres pattern (“U” shape) was used on the edge of the flap and full coverage was achieved under moderate tension (Fig.5).

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Figure 5. Dorsal aspect of the tail after final closure

Usually after advancing a flap “dog ears” will result at the base. In this particular case minimal “dog ears” were present. For a cosmetic appearance and to preserve the soft tissue, central suture technique was performed on the lateral sides of the skin flap due to crescent shaped defect. There are many ways to close up a crescent shaped defect but in this particular case central suture technique was chosen to avoid “dog ears” removal. First simple interrupted suture was placed in the middle of the defect and after, another sutures in the middle of the two defects obtained and so on until complete closure.

The central closure technique distributes the “dog ears” all along the sutures line in small increments (Fig.6a, 6b). In the end, the final aspect of the tail in relaxing position was changed due to advancement flap. The tail gain a curved up position (Fig.6).

Figure 6. Central suture technique. (a) Left lateral view of the tail illustrates no “dog ear” present at the base of the flap due to suture technique. The black line show the curved shape of the tail after the final closure. (b) Illustration of closure of crescent shape defect¹.

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Fig 6

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Fig 6

Postoperative care

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Figure 7. Postoperative view after bandage application

For protection, a soft padded bandage was used to cover the surgical site, this being made up of square gauze applied on top, fixed in place with an elastic band; Stirrups were applied over the gauze and extended proximally to the base of the tail and Vetrap was used as a last layer (Fig.7).

The patient was sent home with booster collar to prevent self trauma and 3 days of robenacoxib, also in the surgery day a NSAID injection was administered with the same nonsteroidal anti-inflammatory drug. Until the first recheck (3 days post surgery) the bandage has fallen due to excessive tail movement in 24 hours but the owner apply another one at home; Four days after surgery the patient present for the first recheck, on inspection the tail was less curved in compare with the day the surgery was performed and no complications were present. The owner reports the patient was comfortable at home after surgery, and did not show any changes in behavior. The same bandage was applied in the same manner and this time did not slip until the second visit. The patient has presented for sutures removal in day 10 aftert surgery . No postoperative complications were present and the tail was less curved upwords. One last visit was 34 days after surgery. Due to the weight of the tail, continous tension was applied on the skin over time and the natural position was regain (the processes of mechanical creep and stress relaxation) (Fig.8). The owner reptorts the patient was comfortable in all this period and does not seem to be disturbed by surgery.

Figure 8. Ventral (A) and right lateral (B) aspect of the tail after sutures removal – 10 days post surgery; (C) Dorsal view of the tail 34 days after surgery.

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Fig 8

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Fig 8

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Fig 8

Histopthologic result and prognosis

The mass (Fig. 9) was put into a containter with formol and sent to the lab for histopathologic examination. Pilomatricoma partially ruptured and mineralized, associated with moderate granulomatous inflammation. This is a benign tumour of the hair follicle, slow growing, non-invasive, and generally rarely metastasizes (malignant variant exists but is rare). was the diagnosis and clear margins were achieved and the prognosis is was good. Poodles, Schnauzers and Kerry Blue and Bedlington terriers may be predisposed.

Wound management part 2: The approach of traumatic wounds

May 4, 2019

Florin Delureanu

DVM, MRCVS

March 2017

Introduction

From a general point of wiev, a traumatic injury is defined as a physical damage caused by an external factor. Even if we talk about a road traffic accident, a burn or projectile injuries, all of them represents a trauma for the body. Because the first part of this series described the physiologic process of healing and how can wounds be recognized according to the phase in which they are, the second part will highlight how wounds can be addressed.

Initial assessment of the patient

Due to various types of trauma, the patient should be treated according to the requirements. The patient can be unstable after a road traffic accident, after a fighting with another dog or can be bright, alert if superficial lesions are present (patients that develop wounds due to scratching). If the patient is not stable the plan must be focused first on stabilization by checking the major function (A- airway, B- breathing, C-cardiovascular, etc) followed by a good pain control and assess the life-threatening injuries. In an emergency situations is recommended to cover the wounds with sterile gauze or another type of sterile material to provide haemostasis and to protect against another contaminants that are considered already present in the wound.

Evaluation of the wound

When the patient became comfortable, a wound evaluation must be performed. There are some factors that can help the surgeon to take a decision regarding the local management. Therefore, the following should be considered:

the degree of contamination;
when the injury took place;
the degree of tissue ischaemia;
the amount of tissue loss;
type of wound (burn, snake bite, etc).

About the length of time between the production of the trauma and the presentation of the patient to the clinic and the degree of contamination, wounds are classified as clean, clean-contaminated, contaminated and infected (see details in part1). Because every injury has as a result blood loss, the tissue exposed may have different aspect and can help with the prognosis. The first aspect of the wound may be misinterpreted due to colour and integrity of the surrounding tissues. Many times the skin is crushed due to a powerfull trauma and just small superficial wounds may be present. If at first presentation the skin looks normal and the small wounds have a clean aspect and the trauma happend in less than 4-6 hours not every time will be a good ideea to do a primary closure. Some wounds may have good viability but because the tissues are crushed can develop necrosis and some wounds may have an ischaemic aspect but if the surrounding tissues are not traumatised the evolution can be favorable. As a conclusion, not every time a primary closure will be a wright decision, sometimes wounds need 2-4 days to “settle” depending of the type of trauma. The amount of tissue loss will guide the surgeon to use specific dressings according to depth and length if second intention healing will be elected. Regarding wound type, some specific considerations must be taken. For example, bite wounds should be explored whereas for an early frostbite wound the patient must be rewarmed first.

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Fig1. Basic wound management in six simple steps (Atlas of Small Animal Wound Management and Reconstructive Surgery, 4th Edition Michael M. Pavletic, April 2018

As an approach, wounds can be managed by closure (primary closure, delay primary closure, secondary closure already described in part 1) or can be left for second intention healing.

Second intention healing occurs when a wound is left to heal by contraction and epithelialization. All wounds can be left to heal by second intention but this process may fail at a point or may end without providing a functional outcome. There are some reasons why not every time a complete healing by second intention (especially large wounds and in high motion area-joints, axillary, inguinal) is not recommended: the granulation tissue is very fragile and easly abraded; wound contraction, sometimes excessive, may impede normal function.

Some wounds may fail to completely reepithelialize. Open wound management is indicated in dirty, traumatized, contaminated wounds in which cleansing and debridement is necessary.

Wound preparation – cleansing

To prevent further contamination of the wound in the time of cleaning, all equipement must be sterile. Prior to application of topical treatments, the wound bed must be properly prepared. Initially the wound must be protected with a sterile lubricant (eg. K-Y sterile gel) or sterile gauze soaked in warm saline. After protection, the hair that surrounds the wound must be clipped. The hair represent one of the main foreign body that can imped wound healing in a clean wound. Next, lavage the wound with a proper solution under 7-8 psi to remove the surface contaminants and in the end dry the skin surrounding the wound. This may facilitate the adhesion of the dressing and also will prevent maceration of the skin if the wound is highly exudative.

Wound lavage: many lavage solutions are availabile. Most popular are

Fig.2 Basic kit for wound lavage composed by seringe, 3 way-stop cock, 18G needle, intravenous tube and 500ml bag of sterile saline.

clorhexidine, betadine, Ringer’s and sterile saline. A study from human medicine compared tap water with sterile saline for wound irrigation and showed no difference in occurance of infection. Clorhexidine is availabile in many concentrations (4%, 2%, 0,5%) but for open wounds 0,05% solution should be used. To obtain this concentration, 25ml of clorhexidine 2% must be mixed with 1liter bag of solution. Betadine may be a good option to use in wounds located on the face, particulary near eyes because clorhexidine have very toxic effect if will get in contact with the eyes. Betadine also must be diluted to a proper concentration (0,1%-1% solution). To obtain this solution, 1-10ml of 10% betadine must be mixed with 1 liter bag of solution. As a comparation, clorhexidine is not activated by anorganic matter while as betadine is inactivated by anorganic matter such as blood or exudate. Also a 0,01% clorhexidine gluconate with tris-EDTA solution was described for wound lavage. This combination help lyse Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris. Recently polyhexanide/betaine (Prontosan), a solution or gel containing 0.1% of the antimicrobial agent polyhexanide and 0.1% of the surfactant betaine was described as a lavage solution in wounds with good results.

One of the key of this procedure is not necessarily the type of solution used, but the amount used. A copious lavage of 500-1000ml is recommended. The ideal pressure of 7-8 psi can be provided by different systems. The most cheapest way is to use an 18G needle, a 3 way stop cock, saline bag, 35-60ml seringe and an intravenous tube. Pressure cuff also can be attached to the solution bag and 300mm Hg pressure can be maintained to provide 7-8 psi in the time of lavage. If the pressure is too high, the healthy tissue can break; if the pressure is under 7-8 psi the surface contaminants may not be removed completely.

After cleansing, if the wound is not considered contaminated, primary closure is indicated. Most of traumatic wounds need also debridement.

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Fig. 3 Wet to dry bandage applied on a wound located on the ventral aspect of the metatarsal area in a cat as a nonselective form of debridement

Debridement: can be selective or nonselective. Usually chronic wounds needs debridement but also fresh wounds which present devitalized tissue. Surgical and mechanical debridement are considered nonselective forms. For surgical debridement different surgical instruments can be used (scalpel, scissors, etc.) and adherent bandages (wet-to-dry / dry-to-dry) are used for mechanical debridement.

Surgical debridement must be performed in layers, step by step until the necrotic/ devitalized tissue has been removed and blood can be visible from the wound edges or from the bed. An en block surgical debridement can be performed but this can be limited due to location and size. The wound margins should be closed with suture material or towel clamps can be applied for a temporary closure and after the entire wound is excised, including a margin of healthy tissue. Wound irrigation is also considered a nonselective debridement.There is no strong evidence that cleansing wounds increases healing or reduces infection, but it is almost universally recommended.

Three forms of selective debridement are described: enzymatic, autolytic, biosurgical/ biotherapeutic.

Enzymatic debridement – includes proteolytic enzymes that break down the necrotic

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Fig.4 An example of ointment with papain and urea used for enzymatic debridement

tissue. Papain, trypsin, chymotripsin, fibrinolysine, collagenase, urea are the most common enzymes used for enzymatic debridement. Castor oil, balsam of Peru, desoxyribonuclease are also described.

As an advantage, they will not damage healthy tissue. This type of debridement is used less and less nowadays in wound management because is less effective and needs a long period of time to have the proper effect. Surgical debridement may facilitate enzymatic debridement.

Autolytic debridement – is the most preferate selective debridement. Is less painfull in

compare with the other types. This method involves maintaining a moist environement on the wound so that natural enzymatic “phenomens” can take place. Hydrogels, hydrocolloids and foams are very common used to support autolytic debridement and will be described later as moisture retentive dressings. Due to their high osmolarity, honey and sugar can also be used also for autolytic debridement. They attract the fluid and will keep a moist environement.

Biosurgical debridement – refers to usage of maggots (Lucilia Sericata, Phaenicia

Sericata) and have and FDA approval since 2004. The maggots produce enzymes that dissolve the necrotic tissue and don’t interact with healthy tissue, that’s why the debridement is selective. They are applied in the wound as larva stage (4-7 days of life) and can be left in place 3-4 days. At the moment of application the larvae have 2-3 mm and in 4 days grow until 10-15mm. The optimal activity of the maggots depends on the wound pH. They don’t survive in an acidic environment. An 8.5 pH in the wound is preffered. Each maggot may consume up to 75mg of necrotic tissue every day. They cannot penetrate dry necrotic tissue or eschar therefore are not indicated for this situation.

Moisture retentive Dressings (MDR’s)

Transepidermal water loss represents the the amount of fluid lost by the normal skin. In humans with intact skin the transepidermal water loss is 4–9 g/m²/h. In partial and full-thickness wounds the water loss increase up to 90 g/m²/h. Dressings that have a low moisture vapor transmission value, less than 35 g/m2/h, are considered moisture retentive. In humans was found that the dressing with a water vapor transmission rate of 2028.3 ± 237.8 g/m²/24h was able to maintain an optimal moisture content for the proliferation and regular function of epidermal cells and fibroblasts in a three-dimensional culture model. The process of wound healing can be accelerated by a moist environment. MDR’s retain water and hydrate the tissue and facilitate natural autolytic debridement. All wounds need to be covered with a specific dressing to maintain a proper moisture until full epithelialization otherwise the granulation tissue will get dry and eschar will occur. MDR’s are availabile on the market in various sizes, shapes, thicknesses, with or without adherent margins. They must be applied on top of the wound as a first layer and after can be covered with the second (absorbent layer) and third layer (protective layer).

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Fig.5 Lateral view of a polyurethanic foam. Noticed the convex shape that the foam acquired after beign moistened. Due to this particularity this dressing have a good contact with the wound bed.

Polyurethane foams: is a porous nonadherent dressing that can be used in moderate to high exudative wounds. It absorb several times it’s weight. Is recommended to be used in sterile wounds and regularly must be changed every 3-5 days. With time, the period in which the dressing must be kept in place will change according to the amount of exudate. Some articles described that can be used also over infected wound bed but must be changed every 24 hours.

Can or cannot have adhesive borders and does not transform in gel. It is contraindicated in wounds with low exudate and not recommended in areas with bony proeminence because is very soft and cannot protect the damaged area. In compare with hydrocolloids and alginates, foams are less effective for autolytic debridement.

Alginates (calcium alginate): have high absorbtive properties. It absorbs 20-30 times its weight in fluid. In contact with the exudate, alginates transforms in gel. Is derived from brown seaweed and is recommended in high exudative wounds. It promotes haemostasis and Ca²⁺ stimulates macrophages and fibroblast activity. Is not recommended to be used in low exudative wounds.

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Fig.6 Calcium alginate appearance. Left picture represents calcium alginate sheet applied on dorsal and ventral aspect of metatarsal area in a cat with a degloving injury after surgical debridement; Right picture represents the aspect of calcium alginate 24 hours later in the same patient; Note the transformation from dry fibers in gel and the proximal area in which the dressing was absorbed (yellow arrow).

As a presentation form, alginates are used in flat sheets and can be applied even in narrow cavities. On the market alginates can be found in combination with silver, zinc or honey.

Hydrogels: are indicated in low exudative wounds. They donate fluid to wound but can also absorbe it. Can be found in two presentation forms-sheet and gel. Contains 60-95% water and the cooling effect may decrease pain. Is not indicated in high exudative wounds because maceration can occur. Overgranulation has been reported after usage of hydrogels in excess. In cavitary wounds the gel form is inficated due to better contact. Hydrogels can also be used to soak the dry necrotic tissue.

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Fig.7 Left picture describes hydrogel sheet used on the lateral aspect of digit IV in a dog with and abrasion wound. The wound had partial epithelialization and a small area with granulation tissue and the level of exudate was low. In the right picture gel shaped hydrogel is placed on Primapore.

Various forms of hydrogels combinations are availabile: with hyaluronic acid, alginate, collagen, etc. Can be left in place 3-4 days in non-infected wounds. They are permeable to gas and water and have proven to be a less effective bacterial barrier than occlusive dressings.

Hydrocolloids: have in composition may constituents like sodium arboxymethylcellulose,

gelatin, pectin, and polyisobutylene. Gelatin, pectin, elastomers, alginates, silver, and other materials can be added to these substrates. In contact with exudate it transform in gel and maintain a moist environment. Hydrocolloids are indicated in wounds with low to moderate exudate.

Sheets, powder and paste are the form of presentation. In compare with alginates, foams and hydrogels, the contact face of hydrocolloids is adherent but just on the skin, not on the granulation bed. Regarding permeability, hydrocolloids are semi-permeable to water vapour and oxygen but not permeable to bacteria and other contaminants. Is not recommended in infected wounds. May cause overgranulation.

Fig. 8 Different aspects of hydrocolloid dressing. (a) Fresh hydrocolloid applied on a mild exudative wound in a dog; the dressing have is brown and opaque. (b) View of the dressing 5 days after application on the dorsal metacarpal area in cat. Note the brown dark colour that hydrocolloid achieved. (c) Dressing removal in the same patient in the same day. Note the yellow, gelly and bright aspect due to granulation bed contact.

Miscellaneous dressings

Honey – called also natural dressing, they are composed by glucose, fructose, sucrose, maltose, amino acids, vitamins, minerals and enzimes. Honey is the most popular product used as a topical treatment for wounds; have an antimicrobial effect due to low pH (3-4.5 ), release of small amounts of hydrogen peroxide or the presence of methyglyoxal. Honey promotes autolytic debridement and reduce oedema due to high osmolarity. It was demonstrated that honey have effect against a multitude of bacteria including Pseudomonas spp., MRSA and E. coli. Composition of honey does vary according to the geographical source. Many types of honey are availabile, from raw honey to medical grade. Manuka honey (Leptospermum scoparium) that originates from New Zealand is the most common used in humans and animals for wound care. Medical grade Manuka honey is recommended despite raw honey because raw honey may contain bacteria and fungal contaminants including anaerobic spore‐forming organisms. Recently was developed a new type of honey was developed which is not manuka honey. SurgihoneyRO is an antimicrobial wound gel utilising bioengineered honey to deliver Reactive Oxigen and is superior to Manuka honey. It cames in a variety of form such as gels, sheets, in combination with alginates or simple gauze. Honey is recommended in wounds that needs debridement and is not recommended to be applied over the granulation tissue. Despite the multitude of benefits, the quality of the evidence is variable.

Silver dressings– should be used when infection is suspected. Has been shown that silver ions have an antibacterial effect in contact with the exudate. Because silver ions are activated by a moist environment, is not indicated to be used in wounds with moderate-to-low exudate. There are some evidence that suggest delay healing if silver dressings are used in acute wounds. Is available as gel, sheets, impregned in alginates, foams and hydrocolloids and can be left in contact with the wound up to 7 days. Silver is a broad-spectrum antimicrobial agent that is effective against bacteria, fungi, viruses, and yeast. It has also been proven to be active against MRSA and vancomycin-resistant enterococci (VRE) when used at an appropriate concentration. Silver destroy bacteria due to multiple mechanisms: disrupts bacterial cell walls, inactivates bacterial enzymes, and interferes with bacterial DNA synthesis. Therefore bacterial resistance has yet to be documented, although reports of isolated Escherichia coli and Pseudomonas aeruginosa have shown resistance to silver in vitro. Despite the benefits, some articles concluded that is still a lack of evidence about usage of topical silver and silver dressings for treatment of infected or contaminated chronic wounds.

Collagen dressing: are available in different forms such as granules, powders, sheets, pastes, gels. The collagen from these products derived from bovine, porcine, equine, piscean or avian source. Collagen has been widely used in cosmetic surgery, as a healing aid for burn patients for reconstruction of bone. Is the main structural protein in the extracellular space. Is resistant against bacteria and in this way it helps to keep the wound sterile. Platelets interact with the collagen to make a hemostatic plug. Collagen based dressings need a secondary dressing layer to maintain a moist environment. Products that contain collagen promotes angiogenesis and stimulates fibroplasia. Recently, usage of Tilapia skin fish in veterinary medicine and blue shark skin in human medicine for burns were described with promising results.

Silicone dressings– are used mainly in humans to reduce the hypertrophic scar. The mechanism of action of silicone dressings is not fully understood. It is believed that silicone due to occlusive effect, decrease the oxygen of the tissue until anoxia, environment in which fibroblasts cannot have a normal function and undergo apoptosis. In humans has been shown to help reduce trauma and pain. Silicone dressings were tested in rabbits, rats and horses. Silicone dressings are nontraumatic and the contact surface is adherent but just on the skin surrounding, not to the granulation bed. A comparison between silicone dressing and silicone gel in a controlled trial for treatment of keloids and hypertrophic scar. Compared to the untreated controls, all of the measured parameters including scar size and induration were reduced in both silicone and nonsilicone-treated groups. In 2005, silicone dressing was used with good outcomes in horses with exuberant granulation tissue. In 2017, a review of silicone gel sheeting and silicone gel for the prevention of hypertrophic scars and keloids concluded that was statistical significance in the effectiveness of both of them but most of the trials had poor quality with high or uncertain risk of biases.

Borate glass nanofiber – was developed in 2010 by human engineers and is recognized to have regenerative properties on bones and soft tissues due to stimulation of angiogenesis and osteogenesis. Two borate glasse with (1605) or without (13-93B3) CuO and ZnO were studied along with the silicate-based glass, 45S5 for the potential effect on vascular endothelial growth factor. The study demonstrate that silicate glass is inferior to borate glass. Copper and zinc ions together with calcium, phosphorus, magnesium, etc., stimulate the proliferation of human endothelial and osteoblast-like cells, promote angiogenesis, and stimulate vascular endothelial

growth factor secretion. Osteogenesis is encouraged because the fibers convert to hydroxyapatite.

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Fig.9 Borate based glass nanofiber. Macroscopic aspect, “cotton-candy” like (left picture) and electron microscopy (right picture).

In 2017, borate glass nanofiber was evaluated for treatment of full thickness wounds in six dogs. The study had many criteria: wound cause and location, type and duration of previous wound management, time to granulation tissue formation, time to complete wound healing, subsequent procedures if applicable, outcome, and complications associated with treatment. With a “cotton candy” aspect and soft texture, the borate glass can be applied to any defect, even in deep wounds can be packed. Is not expensive and did not require hospitalization. A veterinary product was developed and is available (RediHeal) for cats, dogs and horses. Because promotes bone growth, the product can be packed also in the defect which result after dental extraction. After application, the fibers degrades at a controllable rate and release ions.

Wet-to-dry Vs MDR’s

· Wet to dry bandages: first they overhydrate and after dessicate the wound bed. As

a result, cells involved in the healing process will lose their function. Because is a nonselective debridement form, when wet to dry bandages are removed normal cells (WBCs, macrophages, granulation tissue) are pulled off with the surface contaminants. The environmental bacteria can penetrate the gauze.

Because is adherent, in the time of removal will be not comfortable for the patients due to pain sensation. Small gauze fibers can remain in the wound bed, will act as a foreign body and will extend the inflammatory phase. They are not expensive but if are used as a sole treatment for wounds, the cost may increase semnificatively due to delay healing and daily replacement.

· Moisture retentive dressings: during the inflammatory phase, support selective

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Fig.9 Characteritics of an ideal dressing

autolytic debridement and promote healing because will keep a moist environment. They are nonadherent and nonpermeable for bacteria so the infection rate is lower in compare with wet to dry bandages. They also require replacement every 3-6 days (depends on the product and the wound appearance) therefore decrease the costs for total wound care. Because MDRs are occlusive or semioclusive in nature, they decrease the pH and oxygen tension in wound and, as a result, WBCs are attracted, angiogenesis and collagen formation are stimulated and inhibit bacteria. MDRs are comfortable not painfull for the patient when are removed from the wound bed. Also they prevents dessication and necrosis.

There is no dressing that meets all the conditions and cannot be considered that one is better than the other. The aim is to use the correct dressing according to the needs of the wound. Therefore, the physiology of wound healing needs to be understood. As an example, even if gauze (wet-to-dry) have many negative consequences, it can be used for debridement as part of wound management and is very effective but contraindicated in the proliferative phase while calcium alginate (MDRs) is less effective and can dessicate the wound bed when is applied on dry wounds.

Regarding moisture, a simple general rule is considered: exudative wounds need dressing that will absorb the fluid and dry wounds need dressings that will deliver moisture. It is detrimential to assess the volume and the appearance of the exudate each time the bandage is changed. A wound with a favorable evolution will produce less and less exudate with a clear clear aspect.

Alternative therapies

Wounds have different behavior and the evolution depends on many factors (localization, degree of contamination, size, etc.). In particular situations, wounds may not heal by second intention or they may decrease in size in the time of treatment but in some cases the proliferation may stop. If surgical closure cannot be achieved, alternative therapies may be considered. As an example, vaccum assisted closure (negative pressure therapy), laser therapy or platelet-rich plasma (PRP) should be considered.

The rhomboid flap

August 6, 2018

Florin Cristian Delureanu

DVM, MRCVS

ABSTRACT

In plastic and reconstructive surgery flaps have an important place not only for the aesthetic results obtained but also because they can be used to cover an area without producing tension. The flap mechanism mainly consists of moving a piece of skin from the donor site and moving it to the recipient site (primary defect). The rhomboid flap have a big versatility because can be done anywhere on the surface of the body. Filling small and large wounds with tissue similar in texture, colour and thickness is the ideal objective of the flap. This article describes the surgical approach of two cases, one with an abscess and the other with a benign tumor located at the cutaneous level, both of which are approached by the use of the rhombic flap.

Introduction

A skin flap represent a partial detachment of a piece of skin and the adjacent subcutaneous tissue with its vascular supply intact. All skin flaps have a pivot point or base. Survival of the skin flap is made by blood circulation through its base during the procedure. From this point of view, it is important that the base of the flap be large enough to prevent necrosis.

Local flaps are based on two types of vascularization: the subdermal plexus or a vein and an artery (figure A; right side- island flap).

Classification of skin flaps is based on blood supply, transfer mode (primary motion), location, composition and configuration (most described in human medicine).
Depending on the transfer method, local flaps are classified as follows:
-advancement flaps: those who advance forward;
-rotational flaps: describe a rotation motion (curvilinear configuration) to the primary defect.

The rhombic flap was invented by a human maxilofacila surgeon called Limberg Alexander Aleksandrovich in 1946. By name, the flap has rhomboid shape with two angles of 120 degrees and two angles of 60 degrees. Depending on the primary defect / lesion pattern which require coverage, the flap angles may change. It is often used in reconstructive surgery of the face in humans: eyelid, floor of nose, alar rim and chin defects with good cosmetic results. This skin flap also called Limberg flap is a transposition flap – the elevated skin will have both advancement and rotation movement when is applied over the primary defect.

How to design the rhombic flap

Whether it is a wound or a tumor, around a defect is drawn a diamond with angles of 120 degrees and 60 degrees as mentioned above. First, the short diagonal that joins the 120 degree angles (BD) must be measured and then extended in the desired direction. The extension (DE) to the outside must have the same length with the short diagonal (BD) and with the sides of the diamond. The next step is to extend another line wich is equal and parallel with the closest side of the diamond (EF). Finally the skin flap is obtained (ADEF).

Figure 1. The sketch of the rhomboid flap.The primary motion of the flap is the motion placed on it to close the primary defect; the secondary motion is the motion placed on the tissue surrounding the primary defect by the flap.

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Figure 2. Transferring the flap to the primary defect. The direction of rotation of the flap is indicated by the purple arrow. After rotation in point A dog ear will occur (yellow elipse). During the rotation the flap describes a 120 degree movement. The higher the angle, the dog ears will be more prominent. The secondary defect will be closed following the transfer of point F to the initial position of the D point

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Figure 3. The final shape of the rhomboid flap. Point D reached point B, point E reached point C and point F reached point D. A is the only point which maintain the initial position.

The surgical defect created can be covered with the rhomboid flap from 4 sides (Picture 4).

Figure 4. The variants of flap usage. The best choice is to select the side with the most laxity because in this way the adjacent anatomical structures will not be disturbed. The flap has a mathematical formula in which all sides are made to be equal.

Case 1

History

Daisy, a six years old female cat of the Maine Coon breed presented with a sebaceous cyst, 2 cm diameter, round shape, locatad on the dorsal lombo-sacral area. The owner says that the cat have a decreased appetite. The pacient was rescued and adopted and was vaccinated just when was young. The cat lives with another 3 cats in the same house, all with the same vaccination status.

General Examination

At clinical examination, apart from the wound, dehydration 6% and a small buccal ulcer behind the last molar on the right mandible were detected. The patient was initially treated with clindamycin and meloxicam for 7 days but no improvement observed. The cyst was infected, with bad smell, partially covered with agglutinated hair and inside soft tissue necrosis was present.

Figure 5. The initial appearance of the wound, 24 hours prior
to surgery.

After inspection, dead space was noticed under the skin around the wound. One day before the surgery we noticed fever (40,1°C) and dehydration 8%. CBC, serum biochemistry and FeLV/FIV test were performed. Neutropenia (0.15 x 10⁹/L, normal range: 1.48 – 10.29) and hyperglobulinemia (57g/L, normal range: 28-51) and decreased ALKP (<10 U/L, normal range: 14-111). IDEXX Snap FeLV/FIV was negative. The cat was hospitalized 24 hours for fluid therapy and i.v. antibiotic (Cefuroxime-Zinacef). After stabilizing the patient the intervention was performed.

Descripting the surgical steps

The area was clipped and clorhexidine was used for local antisepsis. Sterile marker was used to draw the rhombic shape around the primary defect.

Figure 6. Appearance of the wound after cleaning. Necrotic tissue and pus was present in the middle of the wound;

Due to the presence of dead spaces under the skin, the round shape of the primary defect was converted to a rhomboid and the rhombic lines were positioned about 1 cm from the wound margin. In this way the tissue that was not healthy was removed. Identifying the area with the highest laxity is the next step. This was done by pinching the skin around the primary defect. After choosing the appropriate area, the flap that must be transferred was drawn.

The first side of the flap (the extended line outward of the defect) and the second side of the flap (line that is the same length as the first, to the adjacent side of the defect and makes an angle of 60 degrees at the flap apex) were cut and the flap was elevated after undermining

Figure 8. The rhomboid flap is designed. The blue arrow describe the direction in which the flap will be rotated.

Figure 9. The primary lesion was excised and the underlying tissues are undermined.

Figure 7. The picture illustrates the extension to outside of the
short diagonal of the diamond

Skin cuts were made perpendicular with No.10 scalpel blade and and the flap was mobilized with help of Metzenbaum scissors. The surrounding tissues are widely undermined to avoid any tension and the flap is rotated into the recipient site. After rotation, the flap is locked in place by fixing its corners by subcutaneous sutures. The donor site is closed as the flap moves over into the new location. Finally the skin was closed with 4/0 PDX in simple interrupted suture pattern.

Figure 10. Elevation of the flap. Stay suture are used to decrease the risk of flap tip necrosis. This inconvenience usually occurs due to faulty handling during the transfer procedure (usually crushing between fingers).

Figure 11. The flap is rotated in the desired place and the first stich is applied on the maximum point of tension. The second and the third stich are placed on the other two corners of the flap (yellow dots).

Figure 12. Immediate postoperative appearance of the flap. Simple interrupted sutures are used for skin closure

A common unaesthetic appearance after transposed flap was the “dog ears” at the pivot point. In this situation, dog ear was corrected by excising one triangle along one side of its base.

Figure 13. The aspect of the flap at 48 hours after surgery

Figure14. The aspect of the flap in the eighth day after
surgery. The direction of the hair grow is change because of the rotation.

Figure 15. Seventeen days post surgery. The stiches were removed after ten days. No complicatios were encountered. Is very difficult to distinguish the change of the hair growth direction

Case 2

History

Coco, a mix breed male dog, three years old was brought to the clinic because a lump was identified on the skin. Owner reports that the mass was seen some days ago and does not believe it has increased significantly. Also says it makes itching and that the dog often scratch there and bleeds. This was the owner’s only concern.

General examination

No abnormalities were detected after clinical examination except the lump. With a cauliflower aspect, the lump had a small base of implantation and 1,2/1,4 cm in diameter. After palpation of the skin around, no pain or local temperature were identified. FNA and blood tests were recommended before surgery and histopathological examination after. The owner declined for financial reasons the FNA and blood test but accepted the histopathological examination. In this situation, a two centimeter safety margin clearance was decided.

Surgical approach

Surgical steps along with flap drawing were described above except for asepsis. In this case iodine povidone was used.

Figure 16. The mass is identified on the left scapular area after clipping; local asepsis was made.

Figure 17. The diamond is designed around the mass; The mid-third skin of the cranial chest was chosen for transfer

Figure 18. Sectioning on contour lines.Control of bleeding is done by hemostat forceps

Figure 19. The final aspect of the flap; the skin is closed with 3/0 PGA in simple interrupted pattern.

Histopathological result

Description: Cutaneous/ subcutaneous mass composed of chistic masses well delimited by a cheratinized multilayered epithelium with epithelial cells with squamous differentiation oxifiles, mixed with abundant, granular and amorphous keratin; multifocal with the tendency of confluence, inflammatory infiltration with neutrophils, macrophages and epithelial cells is observed. Malignant neoplastic cells are not present in the examined sections.

Interpretation: Benign follicular tumor – pilomatrixoma with associated granulomatous inflammatory process.

Figure 20. Wiev of the flap 4 days after surgery; small necrosis was noticed on the tip of the flap (green arrow).

Figure 21. The aspect of the flap 23 days after surgery; the hair was cut to facilitate flap view. Small crusts are present on the tip of the flap and on the pivot point (blue arrows).Notice the cosmetic scar lines (yellow arrows).

Common complication of the flap

Hematoma;
Bleeding;
Flap necrosis;
Secondary infection.

Short indications for proper surgical procedure

The sides of the rhomboid must have the same length;
The sides of the flap must must have the same length;
Depending on the shape of the primary lesion, the diamond angles may vary in degrees;
Any defect in rhombic shape shows 4 variants in which it can be covered.
The lowest laxity region should be chosen and as far as possible so as not to alter anatomical plans.

Full thickness mesh graft in a cat with degloving wound – case presentation

October 21, 2017

Delureanu FlorinCristian

Dr Delureanu FlorinCristian

Veterinary Center Otopeni

Bucharest, Romania

Introduction

An ample loss of skin with underlying tissue and exposure of deep components (eg. tendons, ligaments, bones) define a degloving injury. This kind of wounds are most frequent seen on the distal limbs, medial tarsus/ metatarsus. The main cause of deglowing wounds is car accident, special when the animal is dragged or pushed by a moving car. In all of the cases bacteria and debris are present in the wound.

Free grafts are described as a piece of skin detached from an area of the body and placed over the wound. There are two tipes of free grafts when we talk about graft thickness: full thickness (epidermis and entire dermis); partial/split thickness (epidermis and a variable portion of dermis). Skin grafts are using when exist a defect that cannot be closed by skin flaps or direct apposition. Two factors influence skin graft survival: revascularization and absorbtion of the tissue fluid.

Case report

A 4 years old female shorthair cat, weighting 3,25kg was presented to our clinic. Before that, the owner was at another clinic for consult and he was disappointed because they recommended euthanasia or amputation of the limb. Besides, the first vet treated the cat with Amoxi+Clavulanic Acid and Nekro Veyxym. The owner said that she went missing for about 10 days.

Clinical examination

Picture 1. Dorsal aspect of the metatarsal wound Deep tissue is affected; low to moderate discharge is present.

Picture 2. Ventral aspect of the wound; Note the big swelling and the holes at the base of the fingers (red arrows)

Picture 3. Deep wound with circular aspect, approximate 1,5cm diameter located near saphenous vein

After a thorough clinical exam we found that all was normal excepting the degloving injury. The back right leg was affected. There was a massive inflammation with infection and a lot of debris on the dorsal surface of metatarsal area and ventral, above metatarsal pad. On the dorsal surface of metatarsal area (Picture 1). Besides, also in the ventral area, another wond proximal to the metatarsal pad and 3 deep holes was identified at the base of second, third and fourth finger (Picture 2). It could be distinguished the chronic aspect. A third lesion was registrated on the same leg, in the medial aspect of the thigh. This wound was deep with a circular shape (Picture 3). We estimated that the lesion occurred about two weeks ago. We register pain and high local temperature after palpation. The cat was stable, normothermic, with normal color on mucous membrane, CRT 3seconds and normal superficial lymph nodes.

Radiograph of the affected back limb

Picture 4a

Picture 4b

Two x-ray views was made to eliminate bone changes or foreign bodies (Picture 4a, Picture 4b).

Picture 4a, 4b- Specialist describe: Suspected slight thickening of phalanges cortical 1 fingers 3-4 and gently bending them. Soft tissue swelling of the tibio-tarso-metatarsian region.

Approach

Picture 5a

Picture 5b

After evaluation, the initial recommendation include a good wound management under anesthesia. Before surgical debridment (Picture 5a, 5b), culture was done.

Picture 5a and Picture 5b – Dorsal and ventral aspect of the lesions after surgical debridment

Next, wound lavage was initiated with one bag of 500 ml of worm saline (the most easy way to deliver fluids on the wound is to connect the saline bag with a administration set to the syringe and needle with a 3-way stop cock a large amount of liquid is needed to be effective).

Picture 6. Wound closure by simple interrupted suture.

Finally, this first stage ends with a wet to dry bandage. A primary wound closure was performed for the lesion placed on the medial aspect of the thigh (Picture 6), after intensive cleaning, removal of foreign bodies and dead skin .

Empirically the cat receive Cefquinome until the result arrive and for pain management we administered Tramadol 3mg/kg and Meloxicam 0,1-0,2mg/kg. The cat recover well after anesthesia.

Culture result

One day before performing surgery, we recived the culture result. Streptococcus canis (++++) was identified and was sensible to many antibiotics. Amoxicilin+Clavulanic Acid (Synulox) was initiate for general therapy and chloramphenicol ointment (Opticlor-Pasteur) for local therapy.

Next, a full thickness mesh graft was used on the dorsal aspect of the limb due to the length and depth of the wound and the other wound was left for healing by second intention, both being protected by bandages. In the next 10 day the limb wounds was treated in the same manner. Removal of bacteria, granulation tissue formation and the beginning of epithelization were supported by next bandages as follows: ·

Day 1 – wet-to-dry bandage was used after surgical debridment. (this kind of bandages adhere to the wound and remove the little layer of dead tissue when we take off). Soaked in warm saline 1-2 minutes before removing, they were changed after 24hours one to the other. Cotton gauze was the primary contact-layer of the bandage.

Day 2 and day 3
Picture 7a Fresh Sorbalgon is applied on both wounds. This dressing can absorb 20-30 times its weight in fluid, stimulate fibroblast and macrophage activity.

Picture 7b Calcium alginate dressing must be changed when the fibres transforms in gel.

– moisture retentive dressing (MDR) – calcium alginate (Sorbalgon-Hartmann) was the primary contact-layer. It is good to use when it exist high exudate like in our patient (Picture 7a, 7b).

Day 4,6 and day 9

Picture 8. Hydrocolloid is indicated because he stimulate granulation and epitelisation and have a good autolytic debridment

– moisture retentive dressing (MDR) – hydrocolloid (Hydrocoll-Hartmann) was the primary contact-layer because the discharge decreased (Picture 8).

Describing surgical procedure:

Picture 9. The wound is refreshed by removing the new epithelium formed around the whole wound

Preoperative surgical site preparation: The cat was placed in left lateral recumbency, with the wound exposed. The limb was clipped entirely and povidone iodine and alcohol was used for aseptic surgery. Sterile warm saline 0.9% was use for wound lavage. Meanwhile a colleague prepare the donor site in the same manner- lower cranio-lateral thorax (right side). Almost 1mm of epithelium that has started to grow from the wound edges over the granulation tissue was removed using a thumb forceps and a no. 10 scalpel blade (Picture 9). A perpendicular incision was made right at the edge of haired skin with epithelium. The wound was incised all around and after that the epithelium was removed by advancing the scalpel blade under the epithelium around

the wound. Then, undermining was performed around the wound edges. A fragment of sterile surgical drape was used over the wound to get the exact shape. The drape “pattern” was placed to the donor area.

To maintain the wound moist, i placed over it a cotton gauze moistened in warm sterile saline 0.9% while the graft is transferred.

Picture 10. The donor site-removing the skin; black arrow show the direction of the hair groth.

Picture 11a. Skin from dorsal thorax is advanced

Picture 11b. Simple interrupted suture is used for skin closure.

The direction of hair groth was marked with a black arrow above the donor site so that the direction of the hair groth on the graft will be the same as the hair groth direction on the skin surrounding the wound. After that, the margins of the drape “pattern” was traced on the skin. The skin of the donor bed was incised with No.10 scalpel balde and removed using thumb forceps and Metzenbaum scissors (Picture 10). The defect left after removing the graft was primary closed by undermining and advancing the skin edges with walking sutures using 3-0 monofilament absorbable suture material and finally the skin was sutured in a simple interrupted suture manner using 2-0 monofilament absorbable suture (Picture 11a, 11b).

Preparing the graft

Picture 12. Final aspect of the skin graft after removal

Picture 13. The skin is stretched on the receiving bed so the incisions made in it expand.

The dermal side of the graft was placed on a polystyrene board with a thickness of 10cm covered with a sterile drape and after that we fixed and stretched with 21G needles. The subcutaneous tissue was removed from the graft. Next, made parallel incisions was made in the graft, 0.5-0.7cm long and apart (Picture 12). At the end, the graft was placed on the granulation bed and sutured with 4-0 monofilament nonabsorbable suture in a simple interrupted suture manner. Additional tacking suture was placed to ensure the expansion of the mesh incision and allow the fluid drainage (Picture 13).

Choosing the right bandage after grafting and aftercare

Picture 14. Grassolind is ointment free of medication, broad mesh, air permeable and exudate; impregnated with neutral ointment. Ointment contain petroleum jelly, fatty acid esters, carbonate and bicarbonate diglycerol, synthetic wax.

It is important to use a nonadherent primary dressing. My initial choise was Grassolind (Hartmann), is sufficiently porous to allow easy passage of exudate from the wound surface, preventing maceration of surrounding tissue (Picture 14). The ventral metatarsal wound maintain hydrocolloid dressing (Hydrocoll-Hartmann) as primary layer. After that, a thin layer of chloramphenicol oinment (Opticlor-Pasteur) was used all around both wounds and over the graft.

Picture 15. Note that the “half clamshell” is extended with approximately 1cm toward fingers (red arrow) so the leg does not touch the ground

Over the first dressings was applied 5cmx5cm compress (Medicomp-Hartmann) and a roll gauze was the second layer. After a few laps of gauze stirrups was placed to secure the bandage in place. Extemporaneous half “clamshell” splint (Picture 15) was made from plastic material wich was curved in such a way that the limb was fixed in semi flexion. The splint is a little bit longer than the extremity of the pelvic limb (“toe-dancing” position), thus provide a maximum relief pressure. In the proximal area, under the splint, I put cotton to prevent pressure injuries on the caudal aspect of the thigh. Applied from proximal to distal and with moderate tension, elastic warp was the final protective layer of the bandage and it was secured at the proximal end with tape.

Changing bandages

The bandage was changed in day 1, 3, 5, 7 and 10 post op. In day 10 the suture material was removed from the graft and from the donor site. From day 17 to day 29 hydrogel (Hydrosorb-Hartmann) was used as primary bandage layer and the bandage was changed from 4 to 4 days. In day 29 no discharge was present in the bandage; the wound was completely healed and 0,2-0,4 mm of hair was present in the center of the graft.

Picture 16. Delayed healing on day 45 – epitelization stopped at this level.

Picture 17b. Honey improve wound nutrition, promotes the granulation tissue and epithelization, reduce inflammation and edema. Also it has a wide antibacterial effect.

Picture 17a. DTL laser type is alaser light emitting diode in the red field (wavelength 650 nm) and infrared (wavelength 808 nm) of the light spectrum with next clinical effect: anesthetic effect; decreases edema and inflammation; activates microcirculation; stimulates wound healing; improves tissue trophicity; reflexogenic effect.

A delayed healing occurred at the wound in the ventral region (Picture 16). From day 29 to day 59 epithelization has advanced very hard and granulation tissue has captured an appearance of ulcer (in this time the wound was asepseptic prepared and hydrocolloid and hydrogel was used as primary layer bandage and without the splint). In day 59 the wound was refreshed on the surface with a scalpel blade and laser therapy (Picture 17a) and medical Manuka honey (Picture 17b) was used daily for 14 days. After that, a complete healing was reached.

Illustrating wounds evolution after surgery

Day 1