**2.3 The equipment**

## *2.3.1 The operating microscope/loupes*

The Operating microscope is used in many different surgical specialities and has been adapted for their particular needs. The Ophthalmic one for example is angled at 45° while the neuro one is used while in standing position. The Plastic and Hand Surgeons use the same one in a sitting position and new the latest ones by Zeiss (Pentero and Kinevo) have 3D images and screens that are facing the surgeon so he does not even have to look down at the field (**Figure 2**)!

The Neuro Microscopes show arterial and venous flow – they also have infrared technology that allows intra-operative visual assessment of blood flow and patency, all with the push of a button.

#### **Figure 2.**

*Operating microscopes. The classic Zeiss microscope came on the S88 floor stand. Now Zeiss has the modern Pentero and Kinevo which can do fluoroscan view as well as show the screen up front (on the right), so the surgeon can operate seeing up, not down, reducing neck strain.*

In cases where the vessel diameter is more than 1.5 mm, it is possible to use high powered loupes (4.2x or even 6.0x) to perform the anastomoses safely (by an experienced surgeon). There are now a number of high-quality loupes in the market from various players that provide an extended field of vision with great clarity. It should be noted that the focal length is fixed, so be sure of your working distance before purchasing one.

### *2.3.2 Surgical instruments*

The surgical set for a microvascular anastomosis should be comprehensive (**Figure 3**), however the number of instruments on the table during the repair should be limited to the ones in use and best housed in a silicone-based beaker of water (**not** saline). There are a few essential instruments that one cannot do without: a good microsurgical needle holder, a straight and curved microsurgical scissors, a pair of fine jeweller's forceps (straight and angled) and a vessel dilator [1]. Obviously, it is essential to have a set of microvascular clamps, both single and double, with the latter optional to be mounted on a frame. I prefer the Acland clamps with a bar across (**Figure 4**), which helps to anchor the suture when repairing the vessel. I also like to use a blunt-tipped curved dissecting micro-scissors (**Figure 5**) for it does not damage the adventitial tissue and the all-important intima during vessel preparation.

#### *2.3.3 Sutures*

The main suture I use for arterial repair of less than 1.0 mm in diameter is the 10/0 by Ethicon; code W2870 – **Figure 6A**. This has a diameter of 1/1000 of an inch and a length of 13 cm which is one inflexion of the wrist across the operating field under the microscope. There is thus no delay in visualisation i.e. one does not have to move one's vision away from the Operating microscope or drop the needle and pick it up again because the suture is too long. For larger diameter vessels, 9/0 Ethilon may be used or even 8/0 but one has to balance between ease of performance and needle penetration causing leaks. For veins, being thin-walled and more

#### **Figure 3.**

*A basic set of microsurgical instruments. Note the fine double hooks on the right and a nerve holder next to the needle holder. The curved (blunt) micro needle-holder is the second from the left and is extremely useful. The instruments should be comfortable to hold and use.*

**147**

**Figure 6.**

*veins (11/0).*

charge to obtain the 11/0 sutures.

challenging to handle, a 10/0 suture is practical. For those more experienced, 11/0 (**Figure 6B**) may be used, although not all theatres carry those. If it is anticipated that the patient's vessels are fragile or small, you may want to forewarn the Sister in

*Ethilon 10/0 and 11/0 sutures from ETHICON. A. The 10/0 suture is 1/1000th of an inch and 13 cm long (W2870, BV75-3 13cm black) B. The 11/0 suture (W2881G, BV50-3 13cm black as in package in inset) is of same length but finer, not visible to the naked eye. These are used at the fingertip for arteries (10/0) and* 

*Double approximator clamps. These thoughtfully designed clamps are mounted on a bar (yellow arrow), where one clamp is fixed whilst the other can slide. Surrounding it is a frame (blue arrows) which assists by allowing one to anchor the suture on to it. The pressure exerted by the clamps (A for artery – green arrow) is* 

*Blunt tipped micro-scissors (curved). These are excellent for dissecting the soft tissue (adventitia) surrounding the vessels for the blunt tips have less chance of puncturing or damaging the vessel (see magnified inset). Also* 

*notice there is hardly a gap when the scissors close (useful feature).*

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

**Figure 4.**

**Figure 5.**

*approximately 30 g [5, 8].*

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

#### **Figure 4.**

*The Current Perspectives on Coronary Artery Bypass Grafting*

before purchasing one.

*2.3.2 Surgical instruments*

during vessel preparation.

*2.3.3 Sutures*

In cases where the vessel diameter is more than 1.5 mm, it is possible to use high powered loupes (4.2x or even 6.0x) to perform the anastomoses safely (by an experienced surgeon). There are now a number of high-quality loupes in the market from various players that provide an extended field of vision with great clarity. It should be noted that the focal length is fixed, so be sure of your working distance

The surgical set for a microvascular anastomosis should be comprehensive (**Figure 3**), however the number of instruments on the table during the repair should be limited to the ones in use and best housed in a silicone-based beaker of water (**not** saline). There are a few essential instruments that one cannot do without: a good microsurgical needle holder, a straight and curved microsurgical scissors, a pair of fine jeweller's forceps (straight and angled) and a vessel dilator [1]. Obviously, it is essential to have a set of microvascular clamps, both single and double, with the latter optional to be mounted on a frame. I prefer the Acland clamps with a bar across (**Figure 4**), which helps to anchor the suture when repairing the vessel. I also like to use a blunt-tipped curved dissecting micro-scissors (**Figure 5**) for it does not damage the adventitial tissue and the all-important intima

The main suture I use for arterial repair of less than 1.0 mm in diameter is the 10/0 by Ethicon; code W2870 – **Figure 6A**. This has a diameter of 1/1000 of an inch and a length of 13 cm which is one inflexion of the wrist across the operating field under the microscope. There is thus no delay in visualisation i.e. one does not have to move one's vision away from the Operating microscope or drop the needle and pick it up again because the suture is too long. For larger diameter vessels, 9/0 Ethilon may be used or even 8/0 but one has to balance between ease of performance and needle penetration causing leaks. For veins, being thin-walled and more

*A basic set of microsurgical instruments. Note the fine double hooks on the right and a nerve holder next to the needle holder. The curved (blunt) micro needle-holder is the second from the left and is extremely useful. The* 

**146**

**Figure 3.**

*instruments should be comfortable to hold and use.*

*Double approximator clamps. These thoughtfully designed clamps are mounted on a bar (yellow arrow), where one clamp is fixed whilst the other can slide. Surrounding it is a frame (blue arrows) which assists by allowing one to anchor the suture on to it. The pressure exerted by the clamps (A for artery – green arrow) is approximately 30 g [5, 8].*

#### **Figure 5.**

*Blunt tipped micro-scissors (curved). These are excellent for dissecting the soft tissue (adventitia) surrounding the vessels for the blunt tips have less chance of puncturing or damaging the vessel (see magnified inset). Also notice there is hardly a gap when the scissors close (useful feature).*

#### **Figure 6.**

*Ethilon 10/0 and 11/0 sutures from ETHICON. A. The 10/0 suture is 1/1000th of an inch and 13 cm long (W2870, BV75-3 13cm black) B. The 11/0 suture (W2881G, BV50-3 13cm black as in package in inset) is of same length but finer, not visible to the naked eye. These are used at the fingertip for arteries (10/0) and veins (11/0).*

challenging to handle, a 10/0 suture is practical. For those more experienced, 11/0 (**Figure 6B**) may be used, although not all theatres carry those. If it is anticipated that the patient's vessels are fragile or small, you may want to forewarn the Sister in charge to obtain the 11/0 sutures.

#### *2.3.4 Other items*

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 cannulas attached to them to differentiate them [3].

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

#### **2.4 The patient**

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 technique must be perfect!

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

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

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 vessel and reduce spasm after the repair has been completed.

#### **Figure 7.**

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

**149**

**Figure 8.**

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

mandatory in peripheral repair.

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

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.

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 exten-

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

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

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

*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.*

grafting which may leave some areas without a blood supply.

*2.4.2 Co-morbidities*

*2.4.3 Skin conditions*

sive inner damage.

with respect [4].

*2.4.4 Operative vessel conditions*

turbulent blood flow [2].
