*2.4.2 Co-morbidities*

*The Current Perspectives on Coronary Artery Bypass Grafting*

cannulas attached to them to differentiate them [3].

*2.4.1 General condition of the patient (e.g. blood pressure)*

vessel and reduce spasm after the repair has been completed.

*white gauze (red trapezoid) keeps the background clear (needles visible).*

Drugs: Syringes of Normal Saline, heparinised saline (1000iu to 50 cc or 100 cc of saline) and Lignocaine 2% are prepared in 10 cc syringes with different coloured

Background material (usually made of plastic and blue or green in colour) to place under the anastomosis site during the procedure can be cut to size and prepared. Micro arrowhead sponges to absorb blood and fluids from the surgical site, multiple small single or double skin hooks, white gauze as background around operative field and some folded towels to support one's wrist are all the minute

The ideal patient is young and healthy with no co-morbidities, but this is far from reality. For replantation surgery, one must weigh the pros and cons of doing the surgery, for life is more important than limb. Main areas to look out for are cardiac, respiratory, renal, hepatic and clotting functions. In the case of coronary by-pass surgery, obviously life is dependent on the microsurgical aspect, hence the

Several factors affect immediate outcome: the blood pressure (BP) of the patient must be above 110/70 mmHg to ensure good flow through the anastomosed part, a low BP is prone to thrombus formation. Thus, even in a heparinised condition, one

Hypothermia is another cause for failure. One must ensure adequate warmth in the theatre, for the patient as well as the vessel. The anastomosed vessel needs to be kept warm with sterile warm bath or gauze moistened in warm water/saline. We place a bottle of saline in the microwave after unscrewing the cap, and heat it up, then use that. Other modalities include placing a sterile container in a hot water bath to heat up the saline within. Lignocaine 2% can be applied locally to dilate the

*The operative field. Note the microscope stand (green rectangle) is away from the field allowing the surgeon space to move to the left or right. The right hand should be supported on a roll of towels (yellow oval) and the* 

has to make sure thrombus formation is not due to inadequate perfusion.

details that will assist in the procedure going smoothly (**Figure 7**).

*2.3.4 Other items*

**2.4 The patient**

technique must be perfect!

**148**

**Figure 7.**

The most commonly encountered co-morbidities are Hypertension and Diabetes. The former is not usually an issue, but the latter may well be. Peripheral vascular disease may affect anastomoses in the digital vessels and affect outcome. In central anastomoses, this may not be an issue, but control of the blood sugar level is mandatory in peripheral repair.

When there are multiple co-morbidities, peripheral repair or replantation or even central vascular repair becomes a challenge, not in the technical aspect, but in terms of long-term outcome, due to it being more likely for complications to develop. Where possible, these must be addressed and stabilised **prior to** surgery.

## *2.4.3 Skin conditions*

When there are clues such the red streak sign (**Figure 8**), it means the digit is unfavourable for replantation because of intimal damage and blood leakage. Vein grafting could be attempted but, in the end, it still may fail because there is extensive inner damage.

Severe or dirty abrasion wounds need to be appropriately cleaned or brushed to avoid contamination of the field and delayed infection destroying the repair. Crush injuries cause damage beyond that which is visible and hence should be approached with respect [4].

### *2.4.4 Operative vessel conditions*

If the digital vessel is found in a coiled state or there is a long trailing digital nerve (**Figure 8**), it means this was an avulsion injury (avulsed from the proximal aspect) and the vessel has suffered intimal damage. The entire length requires vein grafting which may leave some areas without a blood supply.

Locally, if there is damage to the vessel ends, these need to be trimmed to a level where they seem intact. On occasion a flap is to be placed for a defect caused by cancer: one must ensure that an irradiated vessel is not used for the anastomosis.

If there is discordance in the size of the donor and recipient vessel, a few tricks are available to harmonise the size mismatch – which needs to be done – to prevent turbulent blood flow [2].

#### **Figure 8.**

*Red streak sign. The blue arrows point to a faint red line that can be seen where the artery lies. Its intima has been stretched (avulsion injury) and the ecchymosis is due to leakage of blood from avulsed branches. The green arrow shows a red ribbon sign where the vessel is coiled up like a corkscrew due to the avulsion force tearing the layers of the vessel wall. Nerve and tendon may similarly have a long trail. These are poor prognostic signs.*

### *2.4.5 Coagulopathic state*

In the medical history it is important to note any features that may give rise to a hypercoagulable state (age, obesity, OCP intake, etc.) and the reverse where a patient is taking anti-coagulants or herbal supplements such as ginseng. In both cases extra steps need to be taken to ensure complications are kept to a minimum.

## **3. The technique**

The initial debridement, dissection and macro fixation (bone, tendon and ligament repair) may be performed under tourniquet control, but the microvascular repair is usually performed without it [3]. The proximal vessel end is clamped (with a single clamp), the tourniquet is deflated (if it was up), and the vessel then tested for good flow by releasing the single clamp. If it has a good **spurt**, the repair is proceeded with. If it does not, the patient is then checked to have good hydration (BP), temperature and oxygenation. Locally, the wound is checked for damage to the proximal vessel or if there is a crush injury [4]. After ruling this out, and ensuring good flow, the proximal vessel end is clamped and flushed with heparinised saline to remove any clots and blood present. Enough length of the vessel is dissected to allow placement in the double clamps, so that a clear view of the end is seen enabling it to be prepared for suturing under magnification. The opposite vessel is similarly prepared and brought into view with the double clamp, making it clearer with a dark coloured background material (**Figure 9**). To achieve these "clear ends", the vessels needs to be "freed" from the surrounding adventitial sheath that they are housed in. I prefer to use the curved dissecting micro scissors (blunt tips) to avoid damaging the vessel wall (**Figure 5**). Care must be taken not to leave any open branches (ligate or clip them) which will cause oozing later. An IV bolus of 1000 U of Heparin is given at this point. I have found this to be enough in the Asian setting. 3000–5000 U causes spontaneous bleeding and I prefer the lower dose.

Once the ends are placed in the clamps, if they are not smooth, they are cut using the adventitial scissors (straight) to provide a sharp clean edge for suturing. It has traditionally been taught to trim the adventitial layer using the sharp adventitia micro scissors, but the blunt-tipped curved micro-scissors allow closer

#### **Figure 9.**

*Placement of vessel ends in double clamps. The two ends of the severed vessel are placed one end in each clamp and brought closer together until they are a vessel diameter apart.*

**151**

**Figure 11.**

**Figure 10.**

*(C) End result.*

*Tips and Tricks in Microvascular Anastomoses DOI: http://dx.doi.org/10.5772/intechopen.92903*

begin (**Figure 11**).

**3.1 Arterial repair: end-to-end**

of the larger vessel (**Figure 12A**).

*3.1.1 Triangulation method*

dissection. Hold the vessel by the adventitial layer with the jeweller's forceps and go around the circumference taking off at least 2 mm from the edge (**Figure 10**). Finally, dilate both ends with a fine blunt-tipped vessel dilator to about 1.5 times its original diameter and hold it for 2 seconds [5]. This step is important because not only will it allow better visualisation, it will also stretch the smooth muscle of the intima paralysing it for a couple of hours, so it cannot go into spasm. If there is spasm, 1% or even 2% lignocaine can be applied to the vessel wall to alleviate it. The ends are then rinsed with Heparinised saline and the repair is ready to

For an end-to-end anastomosis, the vessel ends are usually aligned (and cut if they are prepared vessels) perpendicularly to the vascular axis. If one end is larger than the other, the smaller vessel may be cut at an angle to match the diameter size

In summary, the technique requires the circumference of the vessel wall to be divided into thirds and a stay suture placed at each point (**Figure 12B**). Subsequently sutures are placed between the three stay sutures and depending on

*Trimming the adventitia. (A) The adventitia is pulled using a jeweler's forceps (left hand) and using the micro-scissors (right hand), it is nipped just at the vessel edge (media). (B) With the hole thus created, one blade of the scissors is used to enter, and then cut the adventitia all the way around the vessel, above and below.* 

*Prepared vessels. After the adventitia is cleared, the vessels are almost translucent. A dark background and bathing them in saline facilitates repair. Inset: clamps facing the surgeon make certain repair techniques easier.*

the size of the vessel one, two or even three may be squeezed in.

*Tips and Tricks in Microvascular Anastomoses DOI: http://dx.doi.org/10.5772/intechopen.92903*

*The Current Perspectives on Coronary Artery Bypass Grafting*

In the medical history it is important to note any features that may give rise to a hypercoagulable state (age, obesity, OCP intake, etc.) and the reverse where a patient is taking anti-coagulants or herbal supplements such as ginseng. In both cases extra steps need to be taken to ensure complications are kept to a minimum.

The initial debridement, dissection and macro fixation (bone, tendon and ligament repair) may be performed under tourniquet control, but the microvascular repair is usually performed without it [3]. The proximal vessel end is clamped (with a single clamp), the tourniquet is deflated (if it was up), and the vessel then tested for good flow by releasing the single clamp. If it has a good **spurt**, the repair is proceeded with. If it does not, the patient is then checked to have good hydration (BP), temperature and oxygenation. Locally, the wound is checked for damage to the proximal vessel or if there is a crush injury [4]. After ruling this out, and ensuring good flow, the proximal vessel end is clamped and flushed with heparinised saline to remove any clots and blood present. Enough length of the vessel is dissected to allow placement in the double clamps, so that a clear view of the end is seen enabling it to be prepared for suturing under magnification. The opposite vessel is similarly prepared and brought into view with the double clamp, making it clearer with a dark coloured background material (**Figure 9**). To achieve these "clear ends", the vessels needs to be "freed" from the surrounding adventitial sheath that they are housed in. I prefer to use the curved dissecting micro scissors (blunt tips) to avoid damaging the vessel wall (**Figure 5**). Care must be taken not to leave any open branches (ligate or clip them) which will cause oozing later. An IV bolus of 1000 U of Heparin is given at this point. I have found this to be enough in the Asian setting. 3000–5000 U causes spontaneous

*2.4.5 Coagulopathic state*

**3. The technique**

**150**

**Figure 9.**

*Placement of vessel ends in double clamps. The two ends of the severed vessel are placed one end in each clamp* 

Once the ends are placed in the clamps, if they are not smooth, they are cut using the adventitial scissors (straight) to provide a sharp clean edge for suturing. It has traditionally been taught to trim the adventitial layer using the sharp adventitia micro scissors, but the blunt-tipped curved micro-scissors allow closer

*and brought closer together until they are a vessel diameter apart.*

bleeding and I prefer the lower dose.

dissection. Hold the vessel by the adventitial layer with the jeweller's forceps and go around the circumference taking off at least 2 mm from the edge (**Figure 10**). Finally, dilate both ends with a fine blunt-tipped vessel dilator to about 1.5 times its original diameter and hold it for 2 seconds [5]. This step is important because not only will it allow better visualisation, it will also stretch the smooth muscle of the intima paralysing it for a couple of hours, so it cannot go into spasm. If there is spasm, 1% or even 2% lignocaine can be applied to the vessel wall to alleviate it. The ends are then rinsed with Heparinised saline and the repair is ready to begin (**Figure 11**).
