Haemostasis In Urology Renal Surgery Percutaneous renal surgery

Percutaneous renal access for bulky stone disease involves a controlled trans-parenchymal stab into the collecting system. Haemorrhage is one of the most significant potential complications of percutaneous nephrostolithotomy (PCNL).1 This complication may be reduced by accurate pre-planning of the tract location either by ultrasonography, 2-D fluoroscopy, mixed ultrasonographic and fluoroscopic guidance, CT, or spiral CT (3-D).2 Bleeding can occur from the renal parenchyma when rigid dilators are serially passed or after dilatation of the access tract causes splitting of a narrow calyceal neck. Use of a balloon dilator as opposed to rigid dilators may reduce the incidence of bleeding during track dilation. The use of periodic screening during tract dilatation to check the position of the dilator tip is recommended to help prevent complications during this stage of the procedure. For the most part, access tract parenchymal bleeding can be controlled sufficiently to permit safe working conditions, by using the next size up of dilator fitted with a co-axial sheath. This serves to tamponade small and medium sized vessels, but such a manoeuvre may worsen venous bleeding from a split calyceal neck. It is rarely necessary to control bleeding from the track by using a double lumen nephrostomy tamponade catheter, where the first balloon retains the catheter within the collecting system while a longer balloon inflated at pressure provides tamponade.3 If significant bleeding is encountered during stone manipulation (often in obstructed, infected systems), the procedure may have to be abandoned due to poor visualisation and to prevent fluid absorption through open vessels. In this situation, it is important to recognise this fact early on without compounding the problem of complicated access and leave a nephrostomy tube of sufficient size in situ for at least a week (our preference is to leave a 3-way 24 Fr. Foley co-axially over a 6 Fr single J stent placed down the ureter over the safety guide wire). After the bleeding has stopped and a mature track has formed, a second look usually ensures a successful outcome. Postoperative bleeding through the nephrostomy tube may be halted by temporarily clamping the tube. This acts as a tamponade, and unclamping is done several hours later by which time the bleeding should have stopped by normal clotting mechanisms.1 Bleeding that does not respond to this conservative treatment may require renal angiography and selective or sub-selective arterial embolisation.1 Open exploration is generally undertaken only in the case of failure of all other modalities, as it often leads to partial or total nephrectomy.1,4 If open surgery is required, provided no further potentially infected stone material remains, betadine soaked Dacron patches can be used as bolsters to anchor the sutures into the potentially friable parenchyma, using deep vertical mattress sutures.

Renal trauma

In case of renal trauma, the majority of penetrating injuries and a small percentage of blunt injuries (Grade II to V), resulting in laceration or vascular injury with a haemodynamically unstable patient, will require surgical intervention. Peterson suggests that surgical intervention should be avoided unless bleeding is life threatening, as in most cases this results in a nephrectomy,5 except in centres of excellence where considerable experience has been gained by sub-specialist urologists. Cass holds the opposite view and recommends early surgical management of major lacerations with or without extravasation.6 It is difficult to assess the correct management as no group has compared operative and non-operative management in a controlled, randomised fashion at a single institution. If an operative route is preferred, the key step is to obtain vascular control by identifying the pedicle early on. If necessary, vascular clamps may be applied after adequate hydration and intravenous administration of a diuretic, such as, mannitol, before the haematoma is cleared away to give adequate exposure.7 Haemostasis is then achieved on the lacerated margins by using a monofilament absorbable suture on a fine tapered needle. This needle is placed in a figure of eight over the bleeding points, if the capsule is intact. It is then sutured over a gelatin foam sponge. If the capsule has been destroyed an omental pedicle flap or Dacron mesh may be used to close the defect. Fibrin sealant is also an effective and a safe topical agent for control of surface bleeding during elective and trauma related urological procedures. It has been used successfully for haemostasis during renal reconstruction.8 Fibrin glue is made by combining a solution of fibrinogen concentrate and factor XIII with a solution of thrombin and calcium.9,10 It is very useful in securing haemostasis, controlling haemorrhage, and sealing anastomoses.11 A disadvantage of this agent is that it requires an almost dry surface before application and, therefore, deep injuries may pose a problem. In contrast an agent, such as, FloSeal® may provide immediate and durable haemostasis and does not require a dry parenchymal surface.12

Nephrectomy

The key to safe working around major vascular structures in the renal hilum is to ensure that all the relevant anatomy is visible and has been clearly identified. It is also essential to ensure adequate visualisation of the inferior vena cava above and below the entry site of the right renal vein, before it is secured. Be wary and look out for abnormal anatomy. Azygous or hemi-Azygous veins may drain directly into the renal vein. Therefore, one must check carefully with adequate retraction, for these anomalies before applying slings or ties. Furthermore, there should be no tension on the vessel when tying sutures. This is necessary to avoid the uncomfortable experience of avulsing the vessel inadvertently and causing torrential bleeding (particularly when tying veins connecting to major structures, such as, the inferior vena cava) and to ensure that one is right on the adventitial layer of the vessel if it is to be clipped. Being on the adventitial layer is important because the surrounding fat may interfere with secure clip application, leaving the lumen partially open. If a vessel, particularly a large vein, is avulsed vascular clamps and sutures may be necessary. Often, however, if the vessel is not large it can be temporarily controlled by the application of an atraumatic Babcock clamp. An open tipped suction device together with the assistance of an experienced anaesthetist is useful at this time. On the left side, it is important to protect the spleen from injury during any retraction of the upper part of the wound. During open nephrectomy, bleeding from the renal bed may be difficult to control due to the nature of the bleeding, which is often multi-focal capillary or venous ooze. In these circumstances, local haemostatic agents can be a useful alternative to packing the wound. Materials that have been used for this purpose include absorbable haemostatic gelatin sponge, cellulose, collagen, FloSeal,® and fibrin glue. These agents act primarily by causing platelet aggregation on contact or by stimulating blood coagulation.9

Major renal vessels may be secured during laparoscopic or open nephrectomy by applying a series of clips on the "stay side''. This is to ensure that the vessel will remain secure even if one of the clips were to be dislodged. In other words, a haemostasis "wall of steel'' would be in place (Fig. 1). In modern practice, regular metal clips that are easily dislodged have been replaced by locking plastic clips (e.g., Weck clips). In open surgery, a Vicryl ligature may also be applied proximal to the clips before the vessel is divided. Other electrosurgical devices have also been developed for sealing vessels up to 5 mm in size. There is a haemostatic system (LigaSure®, Valleylab, Boulder, CO, USA) that works by tissue coagulation and enables fast, effective, and

Fig. 1 ''Wall of steel''.

safe haemostasis in complex urological surgery.13 It may be used for haemostasis during nephrectomy. It is a computer-controlled bipolar diathermy system, which uses radio frequency current applied under pressure. It is designed to optimally seal vessels that are less than or equal to 7 mm in diameter, with minimal lateral thermal damage. It is reported to minimise blood loss and save time14 and is available in the form of different instruments for different applications (Fig. 2).

During laparoscopic nephrectomy, the renal artery is controlled with metal clips, locking plastic clips, or devices, such as, the LigaSure.

Fig. 2 Liga-Sure and application of Liga-Sure.
Fig. 3 Roticulating and straight Endo-GIA.

The renal vein may be secured by any of these or with the Endo-GIA vascular stapler (Fig. 3).

For nephrectomies, where there is extension of the tumour into the IVC (inferior vena cava), proximal and distal vascular control should be gained. Then, cavotomy with extraction of the tumour thrombus is performed. Ligature, patch closure, or vena cava segmental replacement (where tumour invades the wall of the vessel, thankfully, a rare event) may be required in some cases. If the thrombus extends into the intrahepatic portion of the vena cava or above, extensive exposure and isolation of the cava are required and, possibly, mobilisation of the liver, cardio-pulmonary bypass (CPB), or deep hypothermic circulatory arrest (DHCA).15 Bleeding during vena caval surgery is usually encountered from the lumbar veins draining directly into the back of the vessel, leading to steady ooze even when the lumen has been secured between proximal and distal clamps. The key to safe progress under these circumstances is good preparation of sutures and equipment and adequate suction. Sufficient experience to carry out the required manoeuvres in an expeditious manner after the vessel has been opened, is also vital. This is not an operation for the occasional practitioner and should be carried out in a centre of expertise.

Partial nephrectomy

Partial nephrectomy or nephron sparing surgery has been associated with bleeding due to the highly vascular nature of the renal parenchyma. Several suggestions and devices have been used to try and minimise this bleeding.

For partial nephrectomy, the use of biological glue that consists of gelatin, resorcinol, and formaldehyde,16 has been suggested as a successful haemostatic agent. Shekarriz and Stoller described the use of fibrin sealant for controlling surface bleeding during partial nephrectomy.8 Studies on animals have concluded that the use of an absorbable fibrin adhesive bandage facilitates partial nephrectomy by reducing blood loss and ischaemic and total operative times.17 In addition, haemostasis has been successfully achieved by the use of biodegradable hydrogels in porcine models.18

Laparoscopic and open partial nephrectomies have been performed using FloSeal®, a two-component tissue sealant consisting of a gelatin matrix granular component and a thrombin component. This was applied after resection of the tumour, before perfusion of the kidney, and it provided immediate and durable haemostasis.12 It acts by activating the coagulation cascade, while maintaining a haemostatic plug that is not easily displaced. During blood contact, the gelatin particles swell and produce an effective tamponade.

A new ready-to-use haemostatic agent, TachoComb® (Nycomed Austria GmBH, Linz, Austria), consisting of a collagen sheet coated on one side with human fibrinogen, bovine thrombin, and bovine aprotinin has also been successfully used in surgical operations, including urological surgery.19

The application of argon beam coagulation is an alternative to conventional methods of haemostasis whenever there is a diffusely bleeding operative site, such as, in partial nephrectomy for penetrating trauma.20 The argon beam coagulator acts by producing thermal injury to large surface areas where current constantly arcs to sites of low impedance, leading to eschar formation and delayed tissue necrosis. The argon beam coagulator can also be used to perform the capsulotomy and to weld gelfoam onto the cut surface of the kidney in nephron sparing surgery, as described in an animal model.21 The argon beam coagulator has also been used with oxidised regenerated cellulose gauze for haemostasis following laparoscopic nephron-sparing surgery using ultrasonic shears. It has shown good results for small, solid renal masses.22

Microwave tissue coagulation through the use of percutaneously inserted antenna probes has been used during partial nephrectomy in experimental models. It has been shown to reduce blood loss and operative time, and it also poses minimal risk of vascular injury.23

A novel technique has been described for watertight closure and minimal parenchymal bleeding following partial nephrectomy. This involves the use of porcine small intestine mucosa (SIS).24

Laparoscopic partial nephrectomy has been performed in animal models using an arcing-gap electrosurgical snare. Excellent haemostasis was achieved, and there was no need to control the renal vasculature. In most cases, the haemostasis was adequate with the snare alone. In one case, additional haemostasis was required using the argon beam coagulator.25

Retroperitoneoscopic nephron-sparing surgery using a microwave tissue coagulator has also been performed, for small renal tumours. Minimal blood loss occurred.26 This surgical tool is based on the principle that by radiating a 2450 MHz (12 cm wavelength) microwave from a monopolar antenna within tissue, the heat generated will be limited to within the electromagnetic field generated around the antenna. This will lead to coagulation of protein in that field.27

Hydro-jet cutting is an advanced technology that has been used to create an ultra-coherent water force, which functions like a sharp knife. This technique enables selective parenchymal cutting with preservation of vessels. Coagulation can be applied, as required, via a bipolar thermo-applicator. This technique, when used for partial nephrectomy, improves haemostasis and offers a bloodless operating field with a clear view. It has been described in experimental models and in humans for laparoscopic nephrectomy.28,29

ESWL

Bleeding can be an uncommon complication of ESWL. It is more likely in a patient with uncontrolled hypertension or those with established coagulopathy. Recombinant activated factor VII (Novo Seven® was used successfully in a case where the patient suffered a large sub-capsular and peri-renal haematoma following ESWL. The bleeding was stopped, and there was no obvious accompanying coagulation disorder.30

Renal transplant

Acute postoperative haemorrhage may occur due to disruption of a vascular suture line. It may also occur due to inadequate preparation of the graft bed, undetected or poorly ligated branch of the hypogastric artery, inappropriately ligated epigastric vessels, unrecognised vessel in the renal pelvis, abnormal coagulation mechanisms of the recipients, and spontaneous graft rupture.31 The incidence is increased when dialysis is required in the immediate postoperative period. After diagnosis, urgent emergency re-exploration is usually necessary. If vascular repair or reconstruction cannot be accomplished within a reasonable time, then allograft nephrectomy is indicated. Evacuation of the haematoma is important to prevent bacterial infection.31

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