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.
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
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.
