*3.2.2 Making the arteriotomy*

Place the artery in double clamps. The arteriotomy site must also be similarly cleared of adventitia to a three times length of the proposed defect. Care should be taken while performing this and instruments must be sharp and well approximated.

A suture is placed at the exact site of the arteriotomy and tied off (**Figure 19A**). It is to be used as an anchor for the excised piece. It is lifted taut and using the left hand, a 45° angled cut is made (**Figure 19B**). The blood is washed out and the micro-scissors are switched to the right hand making a similarly 45° angled cut meeting the opposite side exactly [5].

#### *3.2.3 Technique of suturing*

Either one of the three suturing techniques described before (interrupted, one-way-up or continuous) can be used. The key is to start with the right hand on the right-hand side of the arteriotomy and place the suture outside in, then take the donor vessel from inside out (**Figure 19C**). It is a safe practice to place another stay stitch at 180*°* to stabilise the loose donor vessel. Similarly, a stay stitch mid-distance along on the back wall, can be placed to keep it out of harm's way (**Figure 19D**). The most important point to note in the suturing technique is to angle the stitches radially outwards to the arteriotomy to ensure an even spacing and place them as one would tighten nuts on the wheel of a tyre rim, progress from either side and moving to the centre to complete the anastomosis safely (**Figure 19E** and **F**).

#### **3.3 Releasing the clamps**

Once suturing is complete, the clamps are ready to be released but before doing that, make sure the blood pressure is well-maintained, a supply of lignocaine 2%, warm saline, clean gauze and heparinised saline are readily available [8]. Lignocaine is applied to the field and rinsed off with heparinised saline after 2 minutes. The double clamps are approximated, reducing tension on the repair and then the distal

#### **Figure 19.**

*Performing and end-to-side anastomosis. (A) A suture is tied to the arterial wall (media). (B) A "v"-shaped cut is made. (C) The needle is pushed from the artery to the donor vessel, starting from the right side. (D) Two stay sutures at 180° (red arrows) stabilize the donor vessel; one more is put mid-way at the back (light blue arrow). (E) The sutures are placed radially and evenly. (F) Completed.*

**157**

**Figure 20.**

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

but now rely on Osmofundin.

and a steady hand.

**3.4 Achieving patency**

*3.4.1 Evidence of patency*

or a wrongly sutured vessel.

*3.4.2 Testing patency*

occluding it.

not observed in straight vessels.

Acland has described them beautifully [5].

vessel refills promptly, the repair is patent.

one is released first, followed by the proximal one. There will be bleeding, but take the clean gauze, soak it with warm saline and continuously apply light compression on the anastomosis. An infusion of intravenous Heparin is started at this point – I give 4000 U over 24 hours. Previously I would also start the patient on Dextran 40,

After 2 minutes, gently remove the gauze, and rinse with warm saline. If there is no more bleeding, that is good. If there is, you may need to reapply compression and repeat the steps. If it is still spurting, there is a gap which needs closure and this is done with the blood flowing because proximal clamping will result in thrombosis. An assistant provides constant irrigation under which the surgeon performs the suture. If done correctly, it is not difficult but needs intense focus

There are a few signs to suggest that the anastomosis is a success. One must learn

**Wriggling** is movement seen in a curved vessel that is patent and pulsating. It is

There are several tests that can be performed to illustrate patency and Robert

**The Uplift test** shows blood filling and emptying with the systolic and diastolic phases of the heart when an instrument placed under the vessel lifts it up, almost

**The Empty-and-refill test** if done gently provides the most conclusive evidence of patency. A fine curved jeweller's forceps is used to gently occlude the vessel *distal* to the repair. Another pair of forceps is then used to milk the blood in the vessel *distally* and finally the proximal forceps is released (**Figure 20**). If the emptied

*Empty-and-refill test. (A) An angled forceps is used to hold the vessel distal to the anastomosis. (B) A jeweler's forceps is then used to gently occlude the vessel distal to this. (C) The jeweler's forceps is moved in a distal* 

*direction. Upon release of the angled forceps, the vessel will fill up with blood.*

**Expansile pulsation** means the diameter of the blood vessel increases and decreases with each heartbeat and there is patency of flow. **Longitudinal pulsation** if it is seen proximally, implies the blood is 'hammering' against a block (thrombus)

to appreciate the finer points when trying to decipher the result:

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

one is released first, followed by the proximal one. There will be bleeding, but take the clean gauze, soak it with warm saline and continuously apply light compression on the anastomosis. An infusion of intravenous Heparin is started at this point – I give 4000 U over 24 hours. Previously I would also start the patient on Dextran 40, but now rely on Osmofundin.

After 2 minutes, gently remove the gauze, and rinse with warm saline. If there is no more bleeding, that is good. If there is, you may need to reapply compression and repeat the steps. If it is still spurting, there is a gap which needs closure and this is done with the blood flowing because proximal clamping will result in thrombosis. An assistant provides constant irrigation under which the surgeon performs the suture. If done correctly, it is not difficult but needs intense focus and a steady hand.

#### **3.4 Achieving patency**

*The Current Perspectives on Coronary Artery Bypass Grafting*

Place the artery in double clamps. The arteriotomy site must also be similarly cleared of adventitia to a three times length of the proposed defect. Care should be taken while performing this and instruments must be sharp and well approximated. A suture is placed at the exact site of the arteriotomy and tied off (**Figure 19A**). It is to be used as an anchor for the excised piece. It is lifted taut and using the left hand, a 45° angled cut is made (**Figure 19B**). The blood is washed out and the micro-scissors are switched to the right hand making a similarly 45° angled cut

Either one of the three suturing techniques described before (interrupted, one-way-up or continuous) can be used. The key is to start with the right hand on the right-hand side of the arteriotomy and place the suture outside in, then take the donor vessel from inside out (**Figure 19C**). It is a safe practice to place another stay stitch at 180*°* to stabilise the loose donor vessel. Similarly, a stay stitch mid-distance along on the back wall, can be placed to keep it out of harm's way (**Figure 19D**). The most important point to note in the suturing technique is to angle the stitches radially outwards to the arteriotomy to ensure an even spacing and place them as one would tighten nuts on the wheel of a tyre rim, progress from either side and moving

Once suturing is complete, the clamps are ready to be released but before doing that, make sure the blood pressure is well-maintained, a supply of lignocaine 2%, warm saline, clean gauze and heparinised saline are readily available [8]. Lignocaine is applied to the field and rinsed off with heparinised saline after 2 minutes. The double clamps are approximated, reducing tension on the repair and then the distal

*Performing and end-to-side anastomosis. (A) A suture is tied to the arterial wall (media). (B) A "v"-shaped cut is made. (C) The needle is pushed from the artery to the donor vessel, starting from the right side. (D) Two stay sutures at 180° (red arrows) stabilize the donor vessel; one more is put mid-way at the back (light blue* 

*arrow). (E) The sutures are placed radially and evenly. (F) Completed.*

to the centre to complete the anastomosis safely (**Figure 19E** and **F**).

*3.2.2 Making the arteriotomy*

meeting the opposite side exactly [5].

*3.2.3 Technique of suturing*

**3.3 Releasing the clamps**

**156**

**Figure 19.**

#### *3.4.1 Evidence of patency*

There are a few signs to suggest that the anastomosis is a success. One must learn to appreciate the finer points when trying to decipher the result:

**Expansile pulsation** means the diameter of the blood vessel increases and decreases with each heartbeat and there is patency of flow. **Longitudinal pulsation** if it is seen proximally, implies the blood is 'hammering' against a block (thrombus) or a wrongly sutured vessel.

**Wriggling** is movement seen in a curved vessel that is patent and pulsating. It is not observed in straight vessels.

#### *3.4.2 Testing patency*

There are several tests that can be performed to illustrate patency and Robert Acland has described them beautifully [5].

**The Uplift test** shows blood filling and emptying with the systolic and diastolic phases of the heart when an instrument placed under the vessel lifts it up, almost occluding it.

**The Empty-and-refill test** if done gently provides the most conclusive evidence of patency. A fine curved jeweller's forceps is used to gently occlude the vessel *distal* to the repair. Another pair of forceps is then used to milk the blood in the vessel *distally* and finally the proximal forceps is released (**Figure 20**). If the emptied vessel refills promptly, the repair is patent.

#### **Figure 20.**

*Empty-and-refill test. (A) An angled forceps is used to hold the vessel distal to the anastomosis. (B) A jeweler's forceps is then used to gently occlude the vessel distal to this. (C) The jeweler's forceps is moved in a distal direction. Upon release of the angled forceps, the vessel will fill up with blood.*

#### **3.5 Venous repair: end to end**

Repairing a vein is not for the novice and is much harder than an artery. The most obvious reason for this is that the walls are floppy and much thinner, so it is difficult to see the edge after dissection. The other reason is that veins have less adventitial tissue that is rather adherent to its walls, making it challenging to dissect. They are hence also easier to damage unless handled with meticulous care and technique. Last but not least, the slower blood flow makes them prone to thrombosis and even slight damage to the intimal walls kicks off the cascade.

#### *3.5.1 Dissection of the vein*

The vascular sheath is flimsy but adherent. Pick it up (making sure one does not damage the venular wall) with a good pair of jeweller's forceps and holding the dissecting (blunt) micro-scissors parallel to the vein, make a hole in it. Then slide the scissors into the space and dissect along the wall of the vein carefully, making sure not to pull out any tributaries with force. These should be ligated with 10/0 nylon or cauterised very carefully. Once released, the vein ends are brought together and placed in the double clamp. The job is made easier if there is an underlying piece of background material and the operative field is flooded with saline or Ringer's lactate. A fine vessel dilator should be used to dilate the vein in two or three directions. It may be difficult to locate the lumen initially, but once this is done, the vein takes a more recognisable form and the lumen becomes visible.

#### *3.5.2 Suturing technique*

In view of the thin walls, there is a tendency for the vein edge to roll inwards and mistakes can be made in taking stitches. Extra precaution should be exercised and if there is any doubt, do not proceed until it is cleared. The first two stay sutures are the most crucial and should be done while bathed in saline. The intermediate sutures may be placed slightly further apart (double the distance) than in an artery because venous pressure is lower.

#### *3.5.3 Checking patency*

Once the repair is complete, the **distal** clamp is released first to flood the repair site and the vessel dilates immediately. Immediate release of the proximal clamp should show a good flow.

A good result will reveal a similar diameter and colour both proximal and distal to the anastomosis. Patency is confirmed by the uplift test. Flow is tested from distal to proximal (along the direction of flow) across the anastomotic site. If there is a block, it will bulge at the anastomotic site and the proximal diameter will be smaller, while the blood in the distal part will progressively become darker.

#### **3.6 Interpositional vein graft**

This procedure is more difficult than a straight-forward venous anastomosis and has multiple steps: getting the arterial defect ready, harvesting a vein for grafting using a meticulous dissection and anastomosing both ends of the graft. It is a necessary skill to acquire for all microsurgeons.

**159**

**Table 1.**

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

During emergency procedures and sometimes even in elective surgeries, the arterial conduit is damaged and needs replacement in part or more. This is where the interpositional vein graft comes in useful. Most times the vein can be harvested from an adjacent site (size is matched) or a distant one (saphenous in the leg). In all instances, the defect must be measured in order to be bridged. Both the arterial ends are dissected free of adventitia and clamped with single clamps in preparation to receive the vein graft.

This is an important step in the procedure and should not be taken lightly. Exact measurement and harvest of the vein graft is to be done by a competent surgeon very carefully. A slightly longer graft is taken in case damage is done to the ends. Too long a graft will cause tortuousness and kinking, while a shorter graft will tend

A length of vein corresponding to the arterial defect is outlined (this is measured before the vein is cut) and using the same meticulous dissection techniques described in Section 3.5, the vein graft is extracted after applying clips (or ligating) both ends. Blood is removed from the vein manually and by irrigation. It is placed in the approximator (double) clamp on one side and the anastomosis is ready to begin. This is started on the right side (for right-handed surgeons) because the artery gives a firm attachment point, and this is needed because the vein graft is freefloating making it difficult to put a suture through. A piece of coloured paper may be used to assist as background material adding oblique cuts to it, so it can help to

The second anastomosis is started after the vein graft is checked to avoid any twisting (this will cause kinks and blockages) and that the double clamp is not

There are many pearls of wisdom and these are best summarised in tables according to the procedure that is being performed. **Table 1** describes general rules while **Tables 2** and **3** enumerate good practices for arterial and venous repair respectively.

> 1. Ensure good hydration. 2. Control of medical conditions (co-morbidities) if any. 3. Peri-operative antibiotics. 4. Review imaging and investigations.

1. Beware of red streak sign. 2. Look for coiled vessels.

3. Look for trailing nerves and tendons. 4. Meticulous pre-dissection. 5. Ensure good spurt of arterial blood.

*3.6.1 Getting the arterial defect ready*

*3.6.2 Harvesting the vein graft*

to stretch and tear or leak.

straddling the repair site.

nutrition and self-relief).

1. Adjust lighting.

in right position.

2. Maintain OR temperature.

*starting the surgery to ensure its success.*

**3.7 Pearls (positive practice)**

hold sutures in place while repair is in progress [5].

**Surgeon Patient**

**Operation theatre Amputated part**

*Pre-operative preparation. This table summarises the various measures the surgeon needs to take prior to* 

1. Pre-operative preparation (well-rested, hydration,

3. Ensure good positioning of machines and instruments. 4. Make sure surgical stool and diathermy foot pedal are

2. Avoid heavy activity the day prior (24 hours). 3. Do not alter (maintain) caffeine intake. 4. Prepare for (elective) surgery mentally.

5. Hands should be well-supported with towels. 6. Place clean gauze as operative field background.
