Microsurgery and skin flap

1. HOLIDAYS

In 1902, Alexis Carrel proposed vascular suture method with three benchmarks.

In 1921, Nylen (Sweden) used a monocular microscope to operate on patients with otosclerosis, opening the era of microscopic surgery.

Perritt used a surgical microscope to suture the cornea in 1940, a breakthrough from microscopy to microsurgery.

In 1960, Jacobson and Suarez succeeded in suturing small blood vessels 1.6 - 3.2 mm in diameter. And that same year, at the American Congress of Surgery, this technique was named microsurgery.

After that, microsurgery had many developments.

In Vietnam in 1979, Professor Nguyen Huy Phan brought microsurgery back to Vietnam.

Right now, there are many medical facilities studying the application of microsurgery in orthopedic trauma.

Microsurgery specialists have made many advances in the use of microsurgery to treat patients.

2. OVERVIEW

Derived from the fact that the naked eye cannot clearly and accurately see structures below 2.5 mm. With surgical instruments and materials that help with optical amplification (surgical magnifiers or surgical microscopes), amplifying surgery has made a breakthrough beyond the natural limits of the eye. people, turning the macro world into the micro world. This makes surgeries more precise and sophisticated, reduces tissue trauma and facilitates tissue healing, significantly improving the quality and outcome of surgery.

The scope of surgical treatment has also been expanded as operations that were previously not possible with the naked eye can now be performed when small structures can be

are easily identified and operations can be performed precisely with the aid of an amplifier.

Microsurgery is an advanced surgical technology that brings revolutionary changes in surgery. It can be used in any surgical specialty, but is not tied to a specific specialty. However, it is widely and most widely applied in orthopedics due to the peculiarities of orthopedics and the fact that the first successful application of microsurgery was made in orthopedics.

3. DEFINITIONS

3.1 Microsurgery

Microsurgery is a surgical field in which procedures are performed under a magnifying glass.

Vascular microsurgery is the part of microsurgery performed on blood vessels less than 2.5 mm in diameter.

Microplastic surgery includes tissue revascularization surgeries to correct acquired or congenital defects or malformations.

3.2 Leather flaps

A flap is a piece of tissue with a blood supply that can be used to repair a tissue defect.

4. SURGERY OF SKIN BLOOD LEVEL

4.1 Blood supply

Skin is divided into three main layers including epidermis, dermis, and subcutaneous tissue. Blood is supplied to the skin primarily by two networks of blood vessels. The deep network is located between the dermis and the subcutaneous tissue, while the superficial network is located in the capillaries of the dermis.

Salmon divided:

• Direct arteries: from deep tissue and through the fascia. Divided into two groups based on: size, length and direction of penetration; main artery name.

+ The axial artery penetrates the deep fascia obliquely upward and distributes into the deep subcutaneous tissue. These arteries are limited to the extremity joints and are significant in size 1–2 mm, originating from the main artery.

The slit arteries are branches of the spindle arteries. They are located in the intermuscular cleft and run perpendicular to the main artery. In some areas, the space between the two abdominal muscles forms the fibrous wall that actually attaches to the bone. After penetrating the scale, these arteries run zigzag, connecting with connections right on the scale. Anastomosis forming the vascular plexus is extremely important when dissection is accompanied by a scale, introduced by Ponten in 1981. Twisted or circular anastomosis for branches form a second vascular plexus in the subcutaneous tissue that The terminal branches are the source of blood perfusion to the skin.

• Indirect artery: originates from the muscular artery through the fascia distributed to the skin. The indirect circulation is simpler, originating from the muscular arteries, the transverse fascia, and distributed to the skin.

Skin and flap blood supply area: The skin is nourished by the three blood sources above, these blood supplies are interconnected. Three terms to note:

• Anatomical blood supply area: dissect as far as possible in the direction of pumping of the axial blood vessel
• Dynamic (physiological) blood supply area: smaller than the upper zone because the peripheral vascular pressure is limited by adjacent blood vessels
• The surgical supply area: is a combination of two factors: the basic geometry that infers blood flow to the flap and the supply expansion factor created by microvascular anastomosis without resistance from the main stem blood.

5. INDICATIONS FOR VIRTUAL SURGERY

As an advanced surgical technology, microsurgery applies to all surgical disciplines. With the development of microsurgery, its applications are dynamically expanding and so are its indications. It is difficult, or even impossible, to define its overall “indication for surgery”. However, despite its wide applications in various sub-disciplines and major surgeries, microsurgery still follows some basic general principles and rules or shares some common features.

The following principles should be observed when determining the indication for microsurgery:

• When similar results can be achieved with simple conventional surgery, relatively complex microsurgery is not indicated.
• When a similar result can be obtained using adjacent tissues without vascularization, vascular grafting of free tissue is not indicated.
• Only tissues from less important organs can be used as donor tissues to repair more important tissues of the recipient site.
• The function and morphology of the receiving site should be considered while minimizing the functional and morphological damage of the donor site.
• If optimal results can only be achieved by complex microsurgery, the choice of simple conventional subocular surgery is not appropriate simply because of the complexity and challenge of microsurgery.

6. BASIC MICROTECHNOLOGY

6.1 Microsurgical Instruments

• Instruments needed to perform vascular microsurgery:

+ Magnifying glass: small (5-9X), medium (10-17X), large (from 18X)

+ Stitching aids

+ Suture: single thread 11-0 (lower pulse 0.7 mm); 10-0 (pulse 0.8 – 1.5 mm); 9-0 (circuit 1.6 – 2.5 mm).

6.2 Cultivate basic skills

6.2.1. Practice using microsurgery glasses

Vị trí phẫu thuật viên: vi phẫu cần thời gian dài dễ gây mệt mỏi cho phẫu thuật viên, do đó, cần chọn tư thế ngồi thích hợp: giữ thẳng xương sống, không nhún vai hoặc ngửa đầu, hơi cúi phần thân trên về phía trước, duỗi thẳng các chi dưới tự nhiên dưới bàn thao tác và giữ chân trên sàn hoặc bàn kê chân, lót cổ tay bằng tấm đệm và không để chúng lơ lửng trong không khí để tránh run các ngón tay.

Fixation and exposure of surgical tissues: because microsurgery requires high precision and slight vibrations under the naked eye will be amplified into significant vibrations under the microscope, the surgical tissue must be firmly fixed. and fully revealed.

Microscope adjustment: microscopes usually operate at a distance of 20 cm. If the distance is too far, the surgeon's observation and manipulation can be difficult, while if the distance is too close, the manipulation instruments will touch the lens. After determining the working distance, the surgeon and assistant will obtain the optimal surgical areas through adjustment of the pupil distance and focal length. The surgeon and assistant usually sit facing each other (180° apart) or side by side. Some microscopes come with viewing lenses for nurses or surgical viewers, but they should avoid touching the viewing lenses.

6.2.2. Practice using microsurgery tools

Grip technique: to ensure precise and stable surgical maneuvers and to minimize vibrations during surgery, surgeons are asked to hold the devices in a pen grip with three or four fingers – hold Firmly grip the microneedle in such a way that it rests on the I, II metatarsal fossa with the thumb and index and middle fingers.

Technique of use: the body of the microsurgical instrument is generally circular, allowing the surgeon to control the instrument with the fingers more easily. The thumb, index and middle fingers are commonly used to run tools, and the wrist is also utilized to support larger movements, e.g. first stitching or tying. Try to avoid movement elbow joint hand during surgery.

6.2.3. Practice basic microsurgery skills

Non-invasive technique: the aim is to minimize the damage caused by surgical instruments and manipulations. Since microsurgery always involves cutting, dissection, ligation, hemostasis, and suturing of tissues, the most common injury during these operations is tweezers. Therefore, surgeons are asked to avoid holding tissues, especially vascular smooth muscle and vascular endothelium, with tweezers unless necessary. Try to keep the coat of the artery in place when tweezers are needed to assist in manipulation.

Exercise hand-eye coordination: unlike in subocular surgery, it is difficult for beginners in microscopic surgery to locate the instruments precisely. So it takes a long time to get used to this condition. The hands-on process is learning how to use tweezers, scissors, tongs and cutting gauze; stitch in the first place; Next learn how to sew gauze or rubber gloves as well as stitch, thread, knot, and cut stitches with tweezers and pliers. Beginners might start with the blood vessels and nerves of a chicken or sheep's thigh, followed by the femoral artery of a mouse. Practical steps include dissection, cutting, end-to-end and end-to-side suturing and check the overall vascular anastomosis.

It takes at least 3 months of practice as well as patience and focused effort to be able to perform very small stitches of good quality.

6.3. Preparing for surgery

6.3.1. Surgical team

Team members include surgeons, anesthesiologists, anesthesiologists, instrumentalists and other members. Review the operating room and assess the need for any special supplies and equipment, such as external fixators, electric drills and orthopedic tables, that are sure to contribute to maximum efficiency and results. superior.

Due to the technical requirements and long surgical time, the surgeon should rest well before surgery to ensure enough energy to meet the prolonged surgery. At the same time, the surgeon must have good microsurgical technique to ensure the quality of the microvascular connection, which is the key to the success of the operation. If possible, the surgery should be done by multiple groups of people. For example, in toe transplant surgery to reconstruct the thumb. When one group is removing the toe, the other group is responsible for dissecting the corresponding tissue in the receiving area of the hand, thus shortening the surgery time.

6.3.2. Steps to perform microsurgery skin flaps

• Preparation of recipient vessels: preoperative angiography or Doppler angiography to determine the presence of recipient vessels
• Understanding Anatomy and Variations
• Prepare the position for
• Flap design
• Know the technique of taking flaps.

7. LEATHER

7.1 Indications and contraindications

7.1.1. Point

Injuries expose components such as bones, tendons, cartilage, orthopedic devices

7.1.2. Contraindications

Absolute contraindications: there are a number of conditions where flap coverage yields poor results and are therefore not indicated, and these include:

• Infection
• Malignant disease
• Failed to create a clean wound margin before skin flap was performed.

Relative contraindications: include personal or family history of thrombosis or coagulopathy, previous exposure to the flap site, history of surgery or trauma potentially affecting the supply blood of the proposed flap and sacrificing the flap site would result in unacceptable disability.

7.2. Some notes before surgery

• Smoking history
• Atherosclerosis
• Peripheral vascular disease
• Steroid use
• Sick đái tháo đường
• Previous surgeries
• Degree of injury
• Patient age and skin condition – Location of defect.

Before a free flap or a large rotator cuff, preoperative angiography can help evaluate circulation and vascularity. In complicated lesions, it is very difficult to close the wound immediately. Adjacent tissues can be used as local flaps for temporary covering. To achieve the satisfaction of the surgeon and the patient, it is necessary to plan and discuss with the patient before surgery. Well-planned flaps deliver aesthetic results with minimal complications at the donor site.

7.3. Classification of skin flaps

7.3.1. By name

• Random flap
• Pipe flap
• Shaft flap
• Free flap
• Skin stem flap
• Reverse current flap
• Skin flaps

• Scales leather flap
• Vascular flap under the skin
• Non-physiological flaps
• Nerve flap
• Piercing circuit flap.

7.3.2. Follow the feeding circuit

• According to the axis

+ The blood supply to the flap from the vascular pedicle is highly reliable, unless there is damage to the vessel, most flaps will live well in the new location.

+ This type of flap requires technical proficiency.

• Random

+ Circulation feeding the flap is based on diffusion by small blood vessels connecting each other from the pedicle to the flap. Nutrition nourishes the flap by dermal or subcutaneous vascular network

+ The pedicle must be wide enough to increase the number of vascular connections. Optimal circulation for blood supply to the flap: the flap should be designed so that the length is no more than three times the width

+ To increase the reliability of the flap, it is possible to use the method of "delaying" the flap before transferring to a new location: the purpose of the "delayed" incision is to allow the vertebral column to assume its role as the blood supply. of the flap before the flap is moved to the new location, by making the number of incisions necessary to create the flap but without separating the flap from the stroma. The flap does not move to the new position; instead, the leather edges are stitched together loosely. Wait about 7 ‒ 10 days after delayed incision before transferring the flap to the receiving site.

7.4. Some basic types of skin flaps

7.4.1. Random spot flap

7.4.1.1. Define

A flap with tissue adjacent to an open wound that needs to be covered.

The given position is where the flap originates. The receiving site is where the tissue defect needs to be covered. 7.4.1.2. Random in-situ flap creation technique – Insensitivity:

+ Local anesthesia: when the area (flap + tissue defect) < 8 ‒ 10 cm + Anesthesia: when the upper area is larger.

- Prepare:

+ Clean the wound: scrape off the surface layer, rinse with salt water, may bleed but only need to be lightly pressed

+ Draw outline of skin flap at the given position before skin incision

If the donor site cannot be sutured, consider skin grafting

+ If the coverage area is > 7 ‒ 8 cm, drainage should be placed (suction tube, penrose, glove piece, etc.). Drainage should be withdrawn after 49 hours.

7.4.2. Shaft flap (belt with constant stalk)

7.4.2.1. Define

A flap consisting of axial arteries and veins parallel to the longitudinal axis of the flap in the flap blood supply region.

Complete flap circulation is established with axial artery blood supply and axial venous return, ensuring nutrition supply to the flap.

7.4.2.2. The technique of taking the shaft flap

At the site of the first incision, skin tension should be considered because the tension is greatest along the slack lines and the smallest along the stretch lines. The incisions should be parallel to the slack line to minimize skin tightening.

In general, axial flaps are obtained from the trunk, neck, or proximal extremities where there is enough loose skin to facilitate closure of the donor skin. There are different ways to get the shaft flap; However, the basic surgical technique is as follows:

• Measure the size of the defect
• Design a skin paddle whose center is in the path of the vascular stalk, taking care to ensure that the cutaneous fascia is within the subcutaneous fat layer.
• It is helpful to leave a fascia and subcutaneous fat around the stalk to avoid injury. It is not necessary to show the pedicle, but if there is evidence of arterial insufficiency in the flap, you may need to expose the pedicle.
• Move the flap to cover the gap
• Close the flap site or with a skin graft depending on the size of the defect.

7.4.2.3. Some flaps have a constant stalk

• Upper limb flap: forearm rotator cuff flap, posterior intercostal flap, etc.
• Lower limb flap: sural nerve flap, outer ankle flap, medial plantar flap, etc.

7.4.3. Piercing circuit flap

7.4.3.1. Define

Is a flap reversal model with blood supply from small perforated skin vessels (diameter not less than 0.5 mm after deep fascia penetration).

It is in the model of the flap with a constant stalk but in a narrow sense.

7.4.3.2. The technique of taking a perforated flap – Skill: need to remember six rules:

+ Try to have a perforation map before surgery

+ Attempts to identify the main perforation with a unilateral limited incision

+ Protect each through circuit until you see the bigger one

+ Choose the best piercing circuit

+ Consider the easiest dissection

+ Other penetrating vessels will be removed after the entire stalk is separated.

• Flap design:

+ Use hand-held Doppler to identify penetrating vessels

+ Measure and estimate the size of the defect

+ Measure the size from the penetrating branch to the most distal part of the cleft, then measure to the proximal side from the penetrating vessel plus 1 ‒ 2 cm

+ The flap width is equal to the gap width plus 0.5 ‒ 1 cm + The elliptical design flap.

• Flap detachment:

+ Use the tourniquet after raising the limb to make the pulse easier to see

+ Peeling from the top of the scale to the bottom of the scale

+ Find a suitable perforating vessel (avoid perforating vessels within 1 2 cm of the chronic wound, as well as those that are too distal to the defect)

+ The pedicle must be separated from the muscle by at least 2 cm, if cleaned the fascia bands can constrict the pedicle to protect the pedicle (especially the vein).

+ Draining the tourniquet 10 ‒ 15 minutes before flap rotation + Drip papaverine or verapamil around the stem + A pair of 2.5x magnifying glasses is required.

7.4.4. Free flap

7.4.4.1. Define

A flap with a new blood supply system established by connecting the feeding vessel to the vessel at the receiving site by microvascular technique, thereby covering soft tissue defects that are difficult to achieve with other techniques. peduncle type.

7.4.4.2. Steps of free tissue transfer

Cut and measure the defect size

• Incision of the skin and dissection of the flap from surrounding tissue. At least one vein and one artery (forming the vascular pedicle) were taken with the flap
• Prepare the arteriole at the receiving site
• Arteries and veins (stubs of the flap) are tied and cut, separating the flap from the body
• The free flap was brought to the cleft, and the flap vein and artery (peduncle) were reattached to the vein and artery prepared at the defect. Circuit connections are made using a microscope or “magnifying glass”.
• The free flap is sutured to the defect, while monitoring to ensure good blood flow is maintained.
• The flap site is sutured or skin grafted.

7.4.5. Weight flap/muscle flap/muscle flap

7.4.5.1. Define

A fascia or musculoskeletal flap is a vascular flap consisting of a portion of the fascia or muscle to cover a defect with or without the skin above.

7.4.5.2. Classify

• Scale flap (Cormack and Lamberty, 1984): based on the type of blood vessel division:

+ Type A: the flap is supplied with blood by many transdermal-muscular vessels into the base of the flap and extends to the entire length of the flap

+ Type B: flap with 1 medium-sized penetrating vessel that is always present in the same position

+ Type C: flap based on many small perforating vessels running between the muscles along the intermuscular septum.

The flap is supplied with blood by deep arteries

+ Type D: musculoskeletal skin flap, which includes parts of adjacent muscle and bone.

• Muscle flap:

7.4.5.3. Technique

• For muscle flaps:

+ Mark and cut skin

+ Dissection into the abdomen of the muscle and related vascular pedicle and deep dissection into the muscular abdomen with or without the upper fascia

Unnecessary perforating branches are clamped or burned and the muscle is separated from the surrounding soft tissue

+ For pedicle flaps, the pedicle is exposed to ensure pedicle rotation is not strained and Doppler signals can be checked to confirm pedicle perfusion. The stalk may not be clearly visible for safer flap transfers

For free muscle transfer, the vascular pedicle is isolated and clamped, and microvascularization is performed rapidly to minimize ischemic muscle damage.

+ The muscle is separated, stopping bleeding at the given site before closing. Drainage and suture to help limit hematoma after removal of large muscles can lead to large hematoma niches, especially large back muscles.

– For muscle flap:

+ The desired skin island is marked and the incision can be widened to facilitate flap dissection

+ The design of skin island in the perfusion area of the flap will minimize ischemia in the distal parts of the flap. Great care must be taken to avoid damage to the skin as muscle damage or perforation will result caseation skin

Once in the muscle layer, perform dissection as previously described for muscle flaps.

A donor site where skin sutures can be obtained, the head or transfer of adjacent tissue to cover or skin grafts may be necessary if large skin flaps are taken.

Quyết định tái phân bố thần kinh cơ khi chuyển mô tự do phụ thuộc vào mục đích tái tạo. Thường là vạt cuống cơ hoặc vạt da cơ, hy sinh thần kinh có thể ngăn ngừa co cơ không mong muốn và dẫn đến teo cơ nên cho phép che kín ở phần rìa tốt hơn. Trong những trường hợp chỉ cần một phần cơ để tạo thành vạt, ví dụ, vạt da cơ thẳng bụng hoặc một phần cơ lưng trên, cần thận trọng bảo tồn nguồn cung cấp máu còn lại của cơ để giảm thiểu tỉ lệ mắc bệnh ở vị trí lấy cơ.