Editing Arterial exposures

== '''General principles:''' ==

* Incision of adequate length
* Use self-retainers where possible
* Ligate lymphatics
* Meticulous haemostasis
* Stay as close to the vessel as possible
* Avoid clamping or crushing heavily calcified segments
* Handle vein conduits carefully
* Use magnification for anastomoses

== '''Carotid''' ==

* See separate topic under 'carotid endarterectomy'

== '''Brachiocephalic''' ==

* Median sternotomy is generally required - same as below for origin of subclavian

== '''Subclavian artery''' ==

* Subclavian origin
** Right angled incision with a horizontal component above the medial third of the clavicle, and a vertical component in the midline over the manubrium and upper sternum (?easier to do a full sternotomy)
** Complete the supraclavicular exposure of the artery as above
** Deepen the vertical incision through subcut tissues and periosteum
** Starting at the suprasternal notch, open a retrosternal plane by finger dissection
** Use sternal chisel and hammer or reciprocating saw to divide the manubrium and sternum in the midline and spread with a self-retaining sternal retractor
** Often need to open pericardium to expose origins of vessels
** Dissect thymus and anterior mediastinal fat to expose the arch of the aorta and the origins of the aupra-aortic vessels
** Close with peristernal wire or strong nylon sutures
* Supraclavicular
** Transverse incision 1cm above the medial third of the clavicle
** Divide platysma in the same plane
** Divide clavicular head of SCM - will expose scalene fat pad
** Dissect fat pad superiorly off the surface of scalenus anterior - may encounter transverse cervical artery and vein within it
** Identify phrenic nerve, passing obliquely from lateral to medial across the front of scalenus anterior
** Divide the tendon of scalenus anterior, protecting the nerve
** Retract the muscle superiorly, exposing the subclavian artery with its vertebral, internal mammary and thyrocervical branches
** Subclavian vein is deep to the clavicle and not normally seen
** On the left, the thoracic duct enters the confluence of IJV and subclavian veins - if damaged, ligate it to prevent chyle leak
** Brachial plexus would be sometimes seen superolateral to this dissection

== '''Axillary artery''' ==

* Proximal:
** Transverse incision below clavicle
** Retract skin flaps cranially and caudally to expose pectoralis major
** Split pectoralis major along the line of its fibres to expose and then incise the clavipectoral fascia beneath
** Axillary fat exposed, which will contain the vessels
** Pectoralis minor tendon is lateral and may need to be divided
** Protect cords of brachial plexus which will be above the artery
* Distal:
** Incision along the deltopectoral groove
** Retract pectoralis major fibres down away from deltoid
** Pectoralis minor tendon divided if necessary
** Protect cords of brachial plexus.

== '''Brachial artery (mid-arm)''' ==

* Position supine with arm abducted 90 degrees on an arm board
* Prep axilla, arm and hand, and consider putting a bag over the hand
* Longitudinal incision in the groove between biceps and triceps muscles on medial arm (typically 5-8cm)
* Diathermy through subcutaneous tissue, being careful to avoid injuring the basilic vein (perforates deep fascia just distal to the middle of the arm, and travels close to brachial artery proximal to this point)
* Incise the deep fascia at the medial border of the biceps muscle and retract anteriorly
** Basilic vein medial to the brachial sheath
* Open brachial sheath
** Median nerve is the most superficial structure encountered
** Artery lies just deep to the median nerve, surrounded by two brachial veins, with the ulnar nerve posteriorly
**
* Ligate crossing vein branches
* Deep brachial artery may be seen on the posteromedial surface of the brachial artery, just distal to the lateral border of teres major
* Beware high bifurcation of brachial artery, which mostly occurs with the two arteries staying in the usual position inside the sheath

== '''Distal brachial artery and bifurcation (cubital fossa)''' ==

* Supine with arm abducted 90 degrees on an arm board
* Transverse or S-shaped incision centred 1cm distal to the antecubital crease (avoid longitudinal incisions across here to prevent flexion contractures)
** Superior longitudinal portion along the medial border of biceps
** Horizontal portion across the flexion crease
** Inferior portion is made lateral to the midpoint of the volar forearm for 4-6cm
* Deepen incision with diathermy
** Look out for basilic vein medially and antebrachial cutaneous nerves
*
* Identify bicipital aponeurosis - divide it and expose the brachial artery underneath, lateral to vein, then median nerve
* Brachial artery usually flanked by two deep veins, with crossing branches
*
* Brachial bifurcation is usually located in the antecubital fossa near the intersection of brachioradialis and pronator teres muscles

== '''Radial artery''' ==

=== '''Mid-forearm:''' ===

** Supine, with arm abducted to 90 degrees on arm board
** 5cm longitudinal incision is made over the portion of the artery to be exposed (can do a long single incision to harvest the entire artery). Landmark is the medial edge of brachioradialis, or a line from the midpoint of antecubital crease to the styloid process of the radius.
** Incise antebrachial fascia along the medial border of brachioradialis
*** In the proximal and middle thirds of the forearm, the radial artery lies beneath the medial fibres of brachioradialis and can be exposed by retracting brachioradialis and pronator teres muscles apart
*** In the distal forearm, the radial artery lies just beneath the antebrachial fascia, between the tendons of brachioradialis and FCR.
*** In the middle third of the forearm, the superficial radial nerve is closely associated with the radial artery and must be carefully preserved
** Radial artery accompanied by paired veins throughout its course
**

=== '''Wrist:''' ===

** Supine, with arm abducted to 90 degrees on arm board
** To explore the artery for ligation/repair, make a longitudinal incision directly over the pulse, beginning just proximal to the level of the styloid process
** Incise the antebrachial fascia just medial to the radius
** Be careful of two deep veins which accompany the artery at this level
** Superficial radial nerve and branches lie between the radial artery and cephalic vein at this level (superficial to antebrachial fascia)
**

== '''Ulnar artery in the forearm''' ==

* Supine with arm supinated and the hand slightly flexed to relax the flexor muscles
* 8-10cm incision four fingerbreadths below the medial epicondyle of the humerus, extending along a line from the medial epicondyle to the pisiform
* Incise antebrachial fascia for the length of this incision
* Develop a plane between FCU and FDS to expose the ulnar artery
** In proximal forearm, lies deep to FDS
** In middle third, lies deep to FCU, which should be retracted medially
** In distal forearm, the artery courses just beneath the antebrachial fascia, just radial to FCU
* Ulnar nerve joins the artery at the border of the middle and proximal thirds of forearm, and is normally found on the artery's medial border


== '''Descending thoracic aorta''' ==

* Left 4th-6th anterolateral thoracotomy

== '''Supra-coeliac aorta''' ==

* Transabdominal approach - note that you are clamping the distal thoracic aorta, through the abdomen and then crura
** Midline laparotomy from xiphoid to umbilicus
** Pack abdominal viscera into the lower half of the abdomen
** Retract left lobe of liver superiorly and to right (increase exposure by dividing the left triangular ligament and folding the left lobe of the liver under a large Deaver retractor)
**
** Enter the lesser sac through a longitudinal incision in the gastrohepatic ligament, approximately 1cm to the right of the oesophagus and extended along the upper margin of the lesser curvature of the stomach. Avoid injuring a replaced or accessory left hepatic artery. Assistant retracts stomach to left with a Deaver.
**
** Incise this posterior peritoneum of the lesser sac with curved Mayo scissors and separate the two limbs of the right crus to create a 5cm opening over the anterior aortic wall
*** Be aware of azygos to right of aorta, and thoracic duct posterior and between the two structures
**
** Clear the medial and lateral walls of the aorta for 2-3cm using blind finger dissection (should be easy)
** Use index and middle fingers to simulate an aortic clamp to see whether enough is cleared
** Use a large, slightly curved aortic clamp, sliding in above the fingers and pushed posteriorly towards the vertebral column to occlude
*** The median arcuate ligament can be cut open to improve exposure
** The clamp will need to be held by an assistant to stop it falling off, or secured to drapes with umbilical tape
** Inform anaesthetist as soon as clamp on and record time
**
* Retroperitoneal approach

== '''Coeliac trunk/SMA''' ==

* Proximal SMA
** Difficult to expose
** Supine, with entire abdomen and lower chest prepped and draped
** Midline laparotomy from xiphoid to umbilicus
** Expose ligament of Treitz
*** Coeliac trunk superior to pancreas
*** SMA inferior to pancreas, but superior to duodenum
*** IMA inferior to duodenum
* Distal SMA
** See separate topic under 'mesenteric ischaemia'


== Infra-renal aorta ==

* Trans-peritoneal
** Can be performed through midline or transverse incision
** Reflect transverse colon superiorly out of abdomen and small bowel to RUQ out of abdomen
** Divide the peritoneal attachments of D3 and D4, and reflect duodenum to the right
** Incise retroperitoneum overlying the aorta
** IMV will be the most superficial venous structure encountered - can be ligated and divided if necessary
** Palpate aorta and dissect it out as far superiorly as the LRV - be wary of lymphatic branches near here, and ligate them. LRV can be dissected all the way back to IVC if necessary and some branches ligated. If needed to be divided, it should be done close to IVC - and is often well tolerated for the kidney due to collaterals. 
** LRA can be exposed posteriorly to LRV.
** RRA can be exposed by freeing up the LRV all the way back to IVC.
** Dissect aorta as far inferiorly as the bifurcation, just watching out for IMA, which is surrounded by a plexus of nerves
*** Iliac origins can be exposed by slight distal extension of the retroperitoneal incision. On the right, that extension can be continued over the entire right iliac system (need to be careful of ureter at iliac bifurcation). Exposure of right EIA is done by incising peritoneum distal to bifurcation.
*** On left, only a few centimetres of left CIA can be exposed easily, because of the sigmoid. Also be mindful of nervi erigentes which pass over the very proximal left CIA. To get to left EIA, reflect sigmoid medially after incising its lateral peritoneal reflection. You can then carry that dissection proximally to get back to the iliac bifurcation.

== '''Common iliac arteries''' ==

* Right
** Wary of superior hypogastric plexus
** Open the peritoneum over the proximal CIA
** Blunt dissection in peri-adventitial plane, careful of ureter
* Left
** May need to mobilise sigmoid mesocolon to get access
** Proximal control at aortic bifurcation
** Try to avoid dissecting the vessel distally - can damage nerves - try just using a swab on a stick




== '''CFA:''' ==

* Longitudinal approach (most common):
** Vertical incision overlying the femoral pulse just distal to the inguinal ligament (if no palpable pulse, you can usually still feel a firm, cylindrical mass just medial to the midpoint of the inguinal ligament)
** Extend incision proximally to expose the inferior edge of inguinal ligament
** Divide subcutaneous tissue directly over the artery using monopolar
*** Look out for small venous or arterial branches of the superficial epigastric and superficial circumflex iliac - ligate as needed
*** Ligate any divided lymphatics (superficial chain is superficial to fascia lata)
*** Saphenous vein may be encountered medial to the artery
*** Place self-retainer
** Change to scissors and divide the fascia lata over the artery
** Open femoral sheath
** Expose the bifurcation by dissecting distally on the anterior CFA - few branches anteriorly. Bifurcation is usually 3.5-4cm below IL, at the point where the CFA becomes slightly narrower. Look out for lateral circumflex iliac vein crossing anteriorly at the bifurcation.
* Transverse incision (most useful when only limited arterial exposure is needed)
** Horizontal incision 2cm above the groin crease, parallel to the inguinal ligament


== '''SFA:''' ==

* Lies in a plane deep to sartorius, crossing over adductor longus. Then passes through the adductor canal, in an aponeurotic tunnel between the anterior and medial compartments of the thigh (created by parts of investing fascia of vastus medialis, sartorius and adductor longus, with SFV deep to SFA, and two branches of femoral nerve).
* Proximal:
** Extend the incision for CFA and mobilise sartorius and retract laterally
** Alternatively, make an incision along the anterior edge of sartorius and cut down, before retracting sartorius laterally
* Mid/distal:
** Position patient with leg externally rotated and knee flexed to 30 degrees
** Longitudinal incision parallel to the lateral border of sartorius (avoids disrupting the blood supply to sartorius)
** Carry incision down to fascia lata, and incise it to expose sartorius
** Reflect sartorius medially to reveal the roof of the adductor canal
** Open fascia to expose the vessels
** Carefully separate adhesions between the vessels, and carefully separate the large venous bridges crossing over the artery, and the saphenous nerve
**

*

== '''PFA:''' ==

* Conventional (proximal) approach
** Begin with longitudinal exposure of the CFA
** Femoral bifurcation encountered 2-5cm distal to inguinal ligament on the lateral or posterolateral side of CFA
** Normally about 2cm of DFA can be exposed before the lateral circumflex vein is encountered on the anterior surface - must be carefully ligated
** Further exposure will probably require division of other crossing veins. Be careful that the femoral nerve is close by.
** Medial and lateral circumflex arteries most commonly originate from DFA, usually near the DFA origin
**
* Lateral (distal) approach
** Useful in re-operative surgery or as an alternative source of either inflow or outflow in bypasses
** Incision parallel to sartorius, 6-7cm distal to the femoral pulsation - can be on either the medial or lateral side of sartorius depending on the situation and the likely course of the bypass graft
** Dissect deep to superficial femoral vessels in a plane between vastus medialis and adductor longus.
** Deep femoral vein found under the intersecting raphes of these muscle fibres
** DFA deep to the vein
**

== '''Popliteal:''' ==

* Above-knee:
** Medial exposure:
*** Supine, leg rotated externally
*** Incision in the distal third of the medial thigh along the anterior border of sartorius, at the lower edge of the vastus medialis (can also be done through the bed of the GSV harvest incision)
*** Fascia lata incised and the sartorius muscle retracted posteriorly
*** Deep fascia incised slightly inferior to the edge of vastus medialis
*** Small artery and vein often encountered as well as a branch of the saphenous nerve - ligate vessels
*** Enter the popliteal space, and encounter the popliteal fat pad. Should be able to palpate the pulse here to direct further dissection. 
*** If having trouble finding it, locate the adductor magnus tendon, which the artery pierces to enter the popliteal space.
*** Artery is usually anterior and medial to the vein (which can be paired), and there are often many bridging veins going across the artery which will need to be divided
** Lateral exposure
*** Internally rotated leg with knee flexed
*** Incise in the distal third of the lateral thigh, between iliotibial tract and the biceps femoris muscle
*** Enter the popliteal space between the short head of biceps femoris and the lateral femoral condyle.
*** Watch out for common peroneal nerve
* Mid-popliteal
** Posterior approach:
*** Prone, with foot and ankle resting on a pad to slightly flex the knee
*** S-shaped incision (to avoid contracture) across the posterior knee joint, from the posterior medial aspect of the thigh across the skin crease and down the posterior lateral leg.
*** Identify small saphenous vein in subcutaneous tissue - it can be ligated or dissected free and retracted to expose the deep fascia
*** Incise deep fascia vertically and retract the sural nerve laterally
*** Tibial nerve visible  - the most superficial of the neurovascular structures - retract laterally along with the common peroneal nerve. This will expose the popliteal vessels.
*** Medial and lateral heads of gastrocnemius can be retracted apart.
* Below-knee:
** Supine with leg externally rotated and the knee flexed 30 degrees
** Longitudinal incision 1-2cm posterior to the medial edge of the tibia, extending a third of the way down the calf
** Divide subcutaneous tissue 
*** Beware of GSV, which is found 1-2cm posterior to the medial border of the tibia
** Divide pes anserinus tendon
** Identify and divide posterior fascia 1cm posterior to tibia
** Identify medial head of gastrocnemius and bluntly mobilise and retract posteriorly, exposing the popliteal fossa
** Gently dissect through the fatty tissue until the neurovascular contents of the popliteal fossa are visible
** Enter the fascial sheath around the vessels (need scissors)
** Carefully dissect the paired popliteal veins free of the artery, ligating any venae comitantes
** Any small arterial branches can be ligated with impunity
** Tibial nerve lies posteromedially

== '''Anterior tibial artery''' ==

* Arises from the lateral aspect of the below-knee popliteal artery and immediately passing through the interosseous membrane, before entering the anterior compartment. Therefore the first 2-3cm are generally inaccessible for bypass and have significant atheromatous disease.
* For above-knee bypasses, need to tunnel carefully either subcutaneously or through the interosseous membrane (can result in kinking/thrombosis)
*
* Proximal/middle third ATA:
** Vertical incision on anterolateral calf, centred on the location of planned anastomosis (palpate cleft between tibialis anterior and extensor digitorum longus muscles approximately at the midpoint between the fibula and tibia and incise directly over the cleft, starting 3cm distal to fibular head)
** Incise overlying fascia in line with skin incision (careful of common peroneal nerve)
** Blunt finger dissection to get in between tibialis anterior and EDL (be careful of small ATA branches)
** Deep in the cleft at the level of the interosseous membrane, the ATA and ATV are usually identified. Often the vein is anterior to the artery.
**
* Distal half
** Similar to above
** Best exposed at the ankle just proximal to the malleoli and flexor retinaculum

== '''Tibioperoneal trunk/proximal posterior tibial/peroneal artery''' ==

* Deep posterior compartment under soleus muscle
* First, perform medial exposure of below-knee popliteal
* Use blunt dissection to enter the potential space where the artery crosses beneath soleus, then use diathermy to divide soleus about a finger-breadth posterior to where it attaches to the tibia
* Watch out for some large veins at this point which will need to be ligated
* Usually easy to identify the arteries once the soleus has been divided
* PTA is more superficial and easily dissected from its adjacent vein
* Look deeper and more laterally for the peroneal artery, which typically runs along the medial side of the fibula

== '''Posterior tibial artery''' ==

* Incision on the medial aspect of the calf about one or two finger-breadths posterior to the edge of the tibia (or, through the base of the GSV harvest incision)
* Incise deep fascia
* Detach soleus from tibia with diathermy to enter posterior compartment
* Posterior tibials should be encountered immediately
* Lots of crossing veins and small side branches
*



== '''Peroneal artery''' ==

* Medial exposure of proximal part is identical to TP trunk exposure
* Middle/distal part can be exposed via a medial incision by detaching soleus from the tibia
* Use a bigger incision than for PTA because of the peroneal artery's deeper location

== '''Dorsalis pedis''' ==

* Anatomy:
** Found on the dorsum of the foot as the continuation of ATA as it passes under the inferior extensor retinaculum of the ankle
* Technique:
** Supine with whole leg and foot prepped
** Longitudinal incision either directly over DP, or just lateral - midway between first and second metatarsals - just distal to the retinaculum (ideally mark it out with Doppler prior)
** Dorsal branch of superficial peroneal nerve is often encountered and can be either retracted or divided with no consequence, but if not in the way, is retracted laterally
** Expose the neurovascular bundle by retracting the EHL and EHB muscles apart
*** Deep peroneal nerve is medial to the artery
*** Might need to control medial and lateral tarsal artery branches, which should be left intact

== '''Infra-malleolar PT and plantar artery''' ==

* Knee slightly flexed with foot elevated on towels or a pad behind the lateral malleolus
* Curvilinear incision between the medial malleolus and the calcaneus, deepening the tissue down to the flexor retinaculum
* Deep fascia divided, which normally reveals the artery (bound by FDL superiorly and FHL inferiorly)
* Artery dissected up to its bifurcation into medial and lateral plantar arteries

[[Category:Vascular]]