Trial of a Transversus Abdominis Plane (TAP) Block in Laparoscopic Colorectal Surgery
Trial of a Transversus Abdominis Plane (TAP) Block in Laparoscopic Colorectal Surgery
Keyhole surgery for bowel disease has brought great benefits, enabling patients to recover
 quicker from surgery and so return to normal activities. Although keyhole surgery reduces
 pain following abdominal surgery, it still causes enough pain to require strong pain killing
 medications such as morphine-like drugs which, although good pain killers, can have a
 detrimental effect on the recovery of bowel function, leading to feelings of nausea and
 vomiting and ultimately delaying recovery. These side-effects can reduce the potential
 benefits from keyhole surgery and our "fast-track" recovery programmes.

 The aim of this project is to assess the effectiveness of a new method of pain control after
 keyhole bowel surgery. The study involves the injection of local anaesthetic into the
 abdominal muscles once the patient is anaesthetised. Although use of local anaesthetic is
 common practice, we are looking at a new technique of injecting it called a transversus
 abdominis plane (or TAP) block. This technique will attempt to block the pain nerves to the
 abdomen prior to the operation beginning. We plan to investigate whether this new technique
 will reduce the amount of pain following keyhole bowel surgery. If successful, it might be
 used to further enhance people's recovery from bowel surgery.
A considerable component of post-operative pain following abdominal surgery arises from the
 anterior abdominal wall. Although laparoscopic surgery has been shown to reduce
 post-operative pain scores compared to open surgery, there is still the problem of abdominal
 pain arising, in particular, from the specimen extraction site. Commonly used regimes to
 counter this pain include intravenous opiate-based patient-controlled analgesia (PCA) pumps,
 although such drugs can have a detrimental effect on the post-operative recovery of bowel
 function and leads to an increased risk of post-operative nausea and vomiting (PONV). The
 consequence of these gastrointestinal complications is that the benefits to patients of
 laparoscopic surgery with enhanced recovery programmes are not fully realised.

 The benefits of adequate postoperative analgesia include a reduction in the postoperative
 stress response, reduction in postoperative morbidity, and in colorectal surgery, improved
 surgical outcome. Other benefits of effective regional analgesic techniques include reduced
 pain intensity, decrease incidence of side effects from analgesics (such as PONV), and
 improved patient comfort.

 The innervation of the anterior abdominal wall comes from nerve afferents from T6-L1 running
 in the neurovascular plane which is found between internal oblique and transversus abdominis
 (TA). The transversus abdominis plane (TAP) block aims to block these nerves with local
 anaesthetic before they pierce the anterior abdominal wall. It has already shown to be
 effective in reducing pain in the first 24 hours after a laparotomy when compared to PCA with
 opiates and shown to have potential in a series of patients undergoing radical prostatectomy.

 The potential improvement of this technique is weighed against the added risks of injecting
 into the neurovascular plane. There is a theoretical risk of a significant flank haematoma as
 a result of injury to the small vessels running with the nerves. In addition there is the
 small risk of inadvertent peritoneal puncture although the risk of any subsequent significant
 injury is very small and would likely be detected at the time of subsequent laparoscopy.
 Although there is one case report of a needle puncture to the liver due to previously unknown
 hepatomegaly, the injury was detected at laparotomy and the consequences were insignificant.

 Experimental Methods and Design Patients would be randomised to receive either 20mls of local
 anaesthetic on each side of the abdomen in the TA plane or to receive no additional
 treatment. Both groups would receive local anaesthetic into the wounds at the end of the
 procedure. The TAP block would take place after induction of anaesthesia but before
 commencement of surgery. The TAP block would be carried out in a standardised manner using
 ultrasound guidance by two experienced anaesthetists with considerable experience in this
 technique. For blinding purposes, the site of entry on the skin for a TAP block will be
 covered with a plaster, irrespective of whether a block has been given.

 A standardised anaesthetic and a standard post-operative analgesia regimen will be given to
 both groups.

 Patients will be withdrawn from analysis if a colorectal resection does not take place or the
 surgery is converted to an open procedure, although data will continue to be collected.
Inclusion Criteria:

 -  Patients undergoing elective laparoscopic colorectal resection at the Queen's Medical
 Centre, Nottingham

 Exclusion Criteria:

 -  Known allergies to the local anaesthetic

 -  Any condition which may cause tolerance to opiates (eg chronic opioid use)

 -  Inability to use a PCA

 -  Patients less than 45kgs for whom local anaesthetic toxicity may become an issue

 -  Adults unable to consent for themselves