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Microvascular Anastomosis

Venkat Ramakrishnan

St Andrews Centre for Plastics and Reconstructive Surgery

Mid-Essex Hospitals NHS Trust

Venkat Ramakrishnan

Ahid Abood, Woan-Yi Chan, Adel Fattah, Yazan Masannat and Venkat Ramakrishnan

The function of the breast is lost when it is removed for breast cancer. The appearance, shape and texture however can be reconstructed to closely resemble a natural breast. This is especially true when the breast is reconstructed using the patients own tissues (autologous reconstruction). The advent of microsurgery has enabled more complex and sophisticated reconstruction using autologous tissue, which has become the gold standard in breast reconstruction.

The undertaking of successful micro-surgical reconstructions goes well beyond the training and expertise of a surgeon skilled in the techniques of microsurgery but necessitates an entire infrastructure to be in place. An infrastructure that includes highly specialized equipment and instruments,ᅠ anesthetists experienced in the intra-operative management of theses cases and nursing staff able to monitor transplanted tissues. The importance of having the correct setting cannot be over-emphasized for the efficient and safe running of the surgery. The preferred anastomosis in our unit (for the DIEP flap) is also described and demonstrated here. Although many of the  points are well described we have decided to revisit them for further emphasis.




Pre-operative positioning is extremely important. When draping it is vital to expose the relevant operative field appropriately for both the breast and plastic teams. The drapes should not reach the floor as this might interfere with the diathermy machines and the microscope when it is needed.ᅠThe arm should be abducted to approximately 90 degrees and not hyper-abducted. Standard venous thromboembolism prophylaxis is undertaken, to include TED  and pneumatic compression stockings.


The procedure is lengthy so intra-operative monitoring is important. This must include  a urinary catheter with temperature probe to monitor urinary output and core temperature. An oesophageal doppler is used to monitor cardiac output and haemodynamic status during anaesthesia.














Flap Inset and Microsurgery Setup


The flap should be contoured and inset prior to anastomosis. To ensure there are no twists on the pedicle the flap is lifted and the pedicle is left to freely uncurl itself in mid air. To commence the anastomosis prior to these two maneuverer  could put the anastomosis in jeopardy. Suction drains also should be inserted prior to the anastomosis and can be utilised to provide continuous, gentle suction throughout it, thereby maintaining a relatively moist but not wet operative field.


Position everything to be comfortable all of the time. The scrub nurse should be on the dominant side of the surgeon. Tilting the table away from the surgeon allows a better angle of the microscope into the axilla and better access..

















One of the problems with axillary anastomosis is the depth of the axilla.To overcome this a length of the vessels should be disected. A wet swab is then placed posterior to the thoracodorsal vessels. This provides a platform that will bring the vessels more superficial, ‘out of the axilla’ and towards the surgeon. The swab is placed directly beneath the vessels and on top of the suction drains so that the drains do not come directly in contact with the vessels at any point.


The scrub nurse should be positioned on the dominant side of the surgeon and in a comfortable position as to be able to hand the instruments effectively. The microscope monitor should be positioned for the scrub nurse to be able to see the steps of surgery to assist effectively.


It is important to do an arterotomy and see a good flow of blood. Even a pulsating artery may have poor flow and even might be ligated more proximally. Also the vein should be released to check for patency and flow.

















The tools necessary to perform the microvascular anastomosis are few in number but highly specialized in nature:


Straight Scissors

A straight pair of microsurgical scissors with sharp narrow tips and a spring-loaded handle. These are predominantly used for cutting sutures.


Curved/Adventitia Scissors

These have a curved blade and sharp tips. The curve allows for close dissection onᅠ vessels while reducing risk of cutting into the lumen.


Jewelers Forceps or Platforms

A pair of straight, fine-pointed forceps are essential. The tips should taper gradually and close precisely so they can capture tissue and suture without scissoring. Typical jeweler's forceps are usually adequate. A variation of the standard forceps has a flat platform along the inner surface of the tip, called a tying stage. This style of tip is designed to facilitate grasping suture because the approximating surface area is much greater than that of forceps that taper to a point.


Vessel Dilators

Vessel dilators are a special-purpose forceps with a highly tapered smooth tip that has a rounded outer surface. The shape of the tip allows it to be inserted into the cut end of a vascular structure.ᅠ The instrument can then be opened passively using the spring tension to dilate the lumen gently.


Needle Holder

The jaws should be gently curved and the handle should have optimal spring tension . The jaws approximate over their entire length and close in a parallel fashion. This allows needles and suture to be grasped securely over the entire length of the jaw.


Vessel Clamps

Vessel clamps are used to interrupt blood flow temporarily until the anastomosis is complete. These come in single and double forms and of varying sizes. The size correlates with the closing pressure exerted. Thus a larger clamp would be used for a larger vessel and vice versa. Most vessel clamps have a broad flat blade and a relatively weak spring tension to occlude vessels gently without causing permanent damage. Aᅠ double clamp assembly with a sliding approximator can be helpful when carrying out an end-to-end anastomosis.


The venous coupler device (Synovis)

Thisᅠis becoming more popular and is a useful tool for anastomosing the vein. In the right hands, the coupler is efficient and can help decrease the total operative time.


Surgical Technique:


Acland clamps are used to hold the vessels at the right length and provide a stable platform to keep the vessels in focus. A simple green backing provides an antiglare surface and a good contrast. The vessels should be lined across the operative field if possible as this makes the ergonomics of anastomosis easier.


All parts of loose adventitia should be trimmed as strand of adentitia close to the edge can cause problems with the patency of the. anastomosis. Thin strands can get trapped in the anastomosis and accumulate considerable amount of thrombus. It is important not to over-thin the vein as the thinner the vein the higher the magnification needed. It is preferable to prepare the anterior wall of he vessels first and then flip the clamp and work on the posterior wall. Once this is done the posterior all is anastomosed first and then the anterior wall after.


limit the amount of irrigation used while using continuous suction applied on the drain helps to keep the field moist. Any excess fluid in the background of the operative field will increase the surface tension and might cause difficulties in picking up the suture material.


The suture should have a favorable suture to needle ratios as large needles will cause larger holes than can cause leakage and problems with the anastomosis. Always hold the wall of the vessel while perforating with the needle to prevent damage especially if the wall is thin. If the needle is blunt always change the needle rather than process as a blunt needle is likely to cause damage to the vessel wall.


After finishing the posterior surface, flip the clamp and use irrigation to help inspecting the lumen. When coming toward the end of the anastomosis of the anterior wall , it is important to take the last three stitches at least before start tying the knots. One of the common causes of failed anastomosis is a bite taken in the posterior wall inadvertently and this can be avoided by taken the last few bites, using irrigation to inspect the lumen and check that the posterior wall is clear and then tie the knots. We usually use only three knots when tying.


























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  8. Matsumura N, Hamada H, Yamatani K, et al. Side-to-side arterial anastomosis model in the rat internal and external carotid arteries. J Reconstr Microsurg. 2001;17:263–266.


Venkat Ramakrishnan

MS, FRCS, FRCS(Plastic Surgery)


Consultant Plastics and Reconstructive Surgeon,


St Andrews Centre for Plastics and Reconstructive Surgery, 

Mid-Essex Hospitals, NHS Trust,

Essex, England 

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