Abdominal wall catheters for postoperative analgesia in patients undergoing open gynaecological procedures

Articles in the Tips and Techniques section are personal views from experts in their field on how to carry out procedures in obstetrics and gynaecology. The aim of enhanced recovery after surgery (ERAS) protocols is to minimise postoperative stress and optimise recovery. This multidisciplinary approach involves surgeons, anaesthetists, pain specialists, nurses, physical and occupational therapists, social services and hospital administration, working together to reduce surgical trauma, manage pain, and shorten hospital stays. One of the key elements of ERAS is effective multimodal pain management, with a focus on minimising opioid use due to significant side effects (e.g., respiratory depression and gastrointestinal adverse effects). Early mobilisation is important, as it reduces the risk of complications, especially pneumonia and venous thromboembolism. ERAS programmes promote multimodal analgesia, often using non-opioid techniques, such as interfascial plane blocks or surgical site infiltration, replacing epidural analgesia as safer alternatives.1, 2 These strategies not only ensure optimal pain control but also support early mobility and faster recovery, associated with improved patient outcomes, high patient satisfaction and reduced healthcare costs.3, 4 Although epidural analgesia can provide effective pain relief for many, there is a small risk of catastrophic complication, with a pessimistic incidence of paraplegia or death of 1.8 per 100 000 (1.0–3.1).5 Less catastrophic side effects include post-dural puncture headache, which varies widely in incidence depending on indication, procedural and patient population from <2% to 40%.6 A Cochrane review, comparing epidural analgesia to patient-controlled analgesia (PCA) with intravenous (IV) opioids for abdominal surgery, found a clinically unimportant reduction in pain at rest at 6 h post-waking (by 5.7 points [on 100-point scale], 95% confidence interval [CI] 1.9–9.5; seven trials, 384 participants; moderate-quality evidence) and was inconclusive with regard to reduction in pain on movement.7 Furthermore, there was an increased risk of failure of analgesia with epidural analgesia and of hypotension requiring intervention to control (relative risk 7.13, 95% CI 2.87–17.75; six trials, 479 participants; moderate-quality evidence). A systematic review of eight studies, including 484 participants, compared epidural analgesia with rectus sheath catheters (RSC) for pain relief after laparotomy.8 They found that, although epidural analgesia slightly reduced the requirement for additional IV analgesia, there was no difference in patient-reported pain scores. Furthermore, RSCs had a lower rate of post-operative hypotension, facilitating earlier mobilisation, compared with thoracic epidural. RSC have been used successfully following major gynaecological oncology surgery for many years and studies have shown they can replace epidural analgesia, with reduced costs and improved patient satisfaction.1, 4, 9 A recent systematic review of locoregional techniques10 for managing post-operative pain after laparotomy for major gynaecological surgery identified nine randomised control trials with 714 participants. There were two studies of RSC: one of surgical placement intra-operatively versus saline placebo1; and one of RSC using continuous infusion of RSC place pre-operatively using ultrasound placement versus epidural block.11 Compared with epidural analgesia, there was no difference in requests for IV PCA (which all participants were given in addition) or other rescue analgesia when continuous infusion RSC were used. Importantly 11/37 in the epidural analgesia group versus 0/36 in the RSC group had post-operative adverse events, including hypotension (4/37 = 10.8%), movement disorders (1/37 = 2.7%) and perception disorder of the lower limbs (6/37 = 16.2%). This study only recruited patients with lower midline laparotomy, however, RSC have been used routinely outside of clinical trials for much larger laparotomies, with good effect.4, 9 The sensory supply of the anterolateral abdominal wall is provided by the thoracoabdominal intercostal nerves (T7–T11), the subcostal nerve (T12), and the L1 spinal nerve. The ilioinguinal and iliohypogastric nerves, originating from the lumbar plexus, innervate the groin, upper hip, and thigh regions. These nerves travel through the transversus abdominis and internal oblique muscles, and then through the transversus abdominis plane (TAP) to reach the skin and muscles of the anterior abdominal wall.12 See Figure 1 for further details. Awareness of anterior abdominal wall anatomy is important for rectus sheath catheter placement. The layers include the superficial Camper's and Scarpa's fasciae, three muscle layers (external oblique [EO], internal oblique [IO], and transversus abdominis [TA]), and deeper layers (transversalis fascia [TF] and parietal peritoneum [PP]).14 Below the arcuate line, internal oblique and transversus abdominis aponeuroses contribute solely to the anterior rectus sheath; above the arcuate line, they split to contribute to both anterior and posterior rectus sheaths (see Figure 2). The two most used surgical incisions for open obstetric and gynaecological surgery are midline and Pfannenstiel incisions. The midline incision offers excellent visualisation and access to the upper and lower abdomen. It can vary in size, extending from the xiphoid process to the pubic symphysis. It utilises the avascular linea alba, minimising blood vessel and nerve damage. RSC, where a local anaesthetic (LA) is injected between the rectus abdominis muscle and its posterior sheath, can be used in these incisions.2, 15 See Figure 3 and www.nysora.com for full details on RSC placement techniques and placement. The Pfannenstiel incision is a transverse lower abdominal incision commonly used in caesarean sections and pelvic surgery. It involves a transverse division of the anterior rectus sheath and a vertical separation between the rectus muscles. The TAP block (plane between transversus abdominis and internal oblique muscles) is commonly used for postoperative pain management in these incisions.16 See Figure 4 and www.nysora.com for full details on TAP catheter placement techniques and placement.4, 6 See the excellent resources available at www.nysora.com for information and diagrams on ultrasound placement of LA blocks for abdominal surgery. Position the patient supine or in a modified lithotomy on the operating table with the abdomen exposed. RSC can be placed either under ultrasound guidance or through direct surgical insertion (see below for details). The procedure requires aseptic technique and can be performed while the patient is awake, sedated, or under general anaesthesia. Ideally, the catheter should be inserted after induction and intubation, but prior to surgical incision, to maximise intraoperative and postoperative analgesic effect.17, 18 The ultrasound probe is topped with ultrasound gel and covered with a sterile probe cover, with sterile saline used on the skin instead of ultrasound gel. Scan the abdomen to assess the depth and location of the sheath, identify anatomy and any blood vessels within the sheath and rectus muscle. The peritoneum and underlying bowel loops should be carefully observed, particularly in patients with low or high body mass index (BMI), as these factors can impact visibility and the ease of insertion.17, 18 To facilitate the insertion of the blunt-ended Tuohy needle, a small incision is made in the skin at the intended insertion site using a 14G IV cannula. The insertion site should be just above the cranial end of the intended incision. An epidural needle, attached to a syringe filled with sterile saline, is inserted through this incision under ultrasound guidance. Ultrasound is used to visualise the advancement of the needle tip. Once the correct anatomical space is confirmed, hydro-dissection is performed by slowly injecting saline to separate the tissue layers between the rectus sheath muscle and ‘tramline’ formed by the posterior rectus sheath/transversalis fascia. Care should be taken to ensure that the syringe is free of air bubbles, which can obscure the ultrasound image. The catheter is threaded into this space, with its progress monitored on the ultrasound screen (see Video S1). To secure the catheter, and reduce infection risk, a cannula is used to tunnel the catheter securely under the skin. Withdraw the Tuohy needle slightly, to avoid inadvertent advancement. Using the cannula, make a tunnel from ~2 cm from the Tuohy needle to come out through the same hole in the skin as the Tuohy needle. Leaving the Tuohy needle in place reduces the risk of damaging the catheter with the sharp cannula needle. This also allows the operator to hit the Tuohy needle with the catheter needle and come up through the same hole, thereby avoiding forming a skin bridge. The cannula needle is withdrawn to leave the plastic catheter to form the tunnel. The Tuohy needle is then threaded off the cannula, using a push/pull Seldinger technique, similar to that used for ureteric stent insertion, to keep the catheter tip static within the tissues, to avoid misplacing the cannula tip. The catheter is then guided through the cannula, ensuring no knots. Once the catheter is correctly positioned, the cannula is withdrawn until the catheter's depth marker is visible at the skin (between 12 and 20 cm depending on the patient's subcutaneous adiposity), confirming proper placement. A sterile delivery system is attached to the catheter, and the first dose of local anaesthetic is administered. A sterile dressing is then applied over the insertion site to secure the catheter. In case the catheter becomes displaced intraoperatively, direct insertion may be necessary. This might involve placing the catheter at the end of the procedure (see below for details).1, 19 At the end of the procedure, a fresh dressing can be applied. If administering anaesthetic in bolus doses, the timing for the next dose of anaesthetic is clearly documented. Alternatively, a continuous infusion can be commenced. However, a randomised controlled study demonstrated a reduced need for opioids, enhanced pain relief and better patients' satisfaction after midline laparotomy with bolus doing compared to continuous infusion.20 The RSC can be inserted directly at the time of surgery, either at the beginning of surgery, when the peritoneum is opened, or at the end of surgery, prior to closure. One hand is placed inside the abdomen and the other hand inserts the Tuohy needle through the skin and fascia. The needle tip is palpated manually and inserted until it is felt to be just superficial to the interface between the peritoneum and muscle layer. It is possible to feel and avoid the inferior epigastric artery (see McDermott et al.19 for further details). The RSC can still be tunnelled, if placed directly, using the tunnelling technique as described above, which will enable the RSC to be used for up to 7 days. Ultrasound-guided insertion of RSC has significant benefits, allowing real-time visualisation of catheter placement within the posterior rectus sheath. This technique enhances the accuracy of anatomical identification, reducing the risk of vascular injury. It is easy to learn, especially by obstetricians and gynaecologists, due to their diagnostic ultrasound training, and should not be the preserve of anaesthetists. Additionally, pre-incision rectus sheath block provides additional intraoperative analgesia and increases time to first post-operative analgesia intervention following laparoscopic surgery.21, 22 However, it requires specialised equipment, training, and time. Direct surgical insertion can be quicker and simpler but carries risks such as contamination of the sterile rectus compartment and catheter dislodgement, leading to inconsistent analgesia.16, 17 Furthermore, in practice, the catheter is commonly misplaced extraperitoneally, rather than superior to the transversalis fascia, which may reduce the efficacy of analgesia.17 The effective postoperative management of RSC on the ward is important for optimal pain control and patient recovery. Training should involve hands-on instruction in RSC handling, securement techniques, and maintaining aseptic conditions to prevent infection. Awareness of how to monitor for signs of local anaesthetic toxicity, understand dosing protocols, and manage infusion pumps is essential. Additionally, team members should be educated on potential complications such as catheter displacement, frank blood in the catheter on drawback, suggestive of IV placement, and entrapment. The ward team should be trained in catheter removal techniques, including checking the integrity of the catheter tip. RSCs can be used alone or in conjunction with PCA to optimise pain relief. Maintaining IV access while the RSC is still in use is important, not only for additional medication administration but also to provide rapid intervention in the event of LAST. LA administration may be achieved through continuous infusion or bolus doses. Boluses can be given every 6 h, such as 20 mL of levobupivacaine 0.25%, or ropivacaine 0.2%, or bupivacaine 0.25% to each catheter, for those >50 kg. The use of specialised infusion pumps can reduce the risk of infection and human error; however, they can limit patient mobility. RSC removal typically occurs by days 2–3 but can be used until day 7. It is possible to omit a bolus dose of LA injection in the RSC with a ‘trial without top-up’, to assess the patient's analgesic control prior to removal. If RSC are still required for analgesia, LA dosing can be recommenced. Educating the patient about the importance of reporting any discomfort or changes at catheter sites, and how to avoid dislodging catheters is useful for effective postoperative management. The use of RSC offers significant benefits for pain management following abdominal surgery. By minimising the need for opioids and supporting early mobilisation, RSCs play an essential role in enhancing recovery and improving patient outcomes. The authors declare no conflicts of interest. JM is Editor-in-Chief of The Obstetrician and Gynaecologist; she was excluded from editorial decisions and had no involvement in the decision to publish. JM and RN conceived the idea for the article. RN planned the article outline and recorded and edited the video, with patient consent for use of images. MS and JM wrote the initial article draft with input from AD and RN. All authors approved the final draft and JM acts as guarantor. We are very grateful to Harry Howard from the Technology Enhanced Learning Team at Somerset Foundation Trust for his artistic talents, patience, good humour and enthusiasm in helping with image and video production. Video S1. Video of insertion of rectus sheath catheter prior to midline incision. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.