Rectus sheath catheters in patients undergoing laparotomy

Intended learning outcomes

1. Learn the anatomy and sonoanatomy of the rectus sheath.

2. Understand the indications, contraindications and complications of rectus sheath catheters.

3. Give an example of a local anaesthetic regime for rectus sheath catheters.

Clinical vignette

A 69-year-old woman with stage IIIc ovarian cancer, hypertension and high cholesterol underwent neo-adjuvant chemotherapy followed by elective primary ovarian cancer debulking surgery by midline laparotomy.

Preoperatively, her anaesthetist discussed analgesia options, and she consented to a multimodal approach. This included a spinal anaesthetic (hyperbaric bupivacaine and diamorphine) before general anaesthesia. At the end of surgery, bilateral rectus sheath catheters (RSCs) were inserted, and a loading dose of 40 ml 0.25% levobupivacaine was administered. An elastomeric pump with 0.25% levobupivacaine was connected to the catheters by a Y-connector and the regime was started 6 h postoperatively at a dose of 14 ml/h. She also received a patient-controlled analgesia (PCA) pump delivering 1 mg morphine boluses with a 5-min lockout.

Postoperative pain was adequately controlled, allowing her to deep breathe, cough and mobilise with physiotherapists. The PCA was stopped on day two and replaced by oral morphine as required. RSCs were removed on day four. She recovered uneventfully and was discharged home eight days after surgery.

Question to be answered

What is the role of RSCs in providing analgesia for patients undergoing a laparotomy?

Discussion

Midline laparotomy is indicated for a range of abdominal surgery procedures. Patients may experience significant problems with postoperative pain after abdominal surgery [1]. The Perioperative Quality Improvement Programme reported that 17.3% of patients who had undergone lower gastrointestinal surgery and 15.1% of patients who had undergone gynaecological surgery experienced severe pain on the first postoperative day [2]. Optimal postoperative analgesia should provide comfort at rest and on movement, as well as enabling mobilisation, deep breathing and coughing to reduce associated perioperative complications [3]. Traditionally, thoracic epidurals had been considered the gold standard technique for providing analgesia following midline laparotomy [1]. However, thoracic epidurals can be associated with several problems, including nerve and vascular injury, failure, disconnection, inadequate analgesia, hypotension, urinary retention and motor block that may slow or hinder recovery [4, 5]. Management of post-laparotomy pain is evolving, with a greater focus on multimodal opioid sparing techniques that facilitate early mobilisation and return to function after major surgery [3]. A survey of UK anaesthetic consultants in 2024 reported that up to 29% of consultants utilised thoracic epidural techniques in patients undergoing midline laparotomies [1]. In contrast, techniques such as intrathecal opioid (90–95% of respondents), rectus sheath blocks ± catheter (89–93% of respondents) and opioid PCA (84–93% of respondents) were used more frequently [1]. RSC, when combined with other techniques such as intrathecal opioids and/or opioid PCA, can provide suitable analgesia for patients undergoing laparotomies. This article focuses on the principles, evidence for and application of RSCs.

Anatomy

The rectus abdominis muscles are a paired group of vertical muscles found on either side of the midline of the abdominal wall [6]. They are separated by the linea alba [6]. They originate from the pubic crest and insert into the inferior costal margin, fifth to seventh costal cartilages and the xiphoid process. The rectus muscle is enveloped by an aponeurotic tendinous sheath called the rectus sheath (Fig. 1) [6]. The sheath is formed by layering of the aponeuroses of the external oblique, internal oblique and transversus abdominis muscles [6].

Figure 1

Figure 1

Rectus muscles and sheath. [Adapted from Anatomy of the Human Body (1918) by Henry Gray [7].]

The thoracic nerves (T6–T11) and subcostal nerve (T12) supply innervation to the skin and muscles of the anterior abdominal wall [6]. The thoracic nerves leave their intercostal spaces, passing deep to the costal cartilages and then continue onto the anterolateral abdominal wall between the internal oblique and transversus abdominis muscles [6]. They then pierce the lateral aspect of the rectus sheath and traverse posterior to the lateral aspect of the rectus abdominis [6]. As they approach the midline, they form an anterior cutaneous branch that pierces through the rectus abdominis and anterior rectus sheath to innervate the skin of the anterior abdominal wall [6].

The key sonographic landmarks for RSC placement are the anterior and posterior rectus sheaths and the rectus muscles (Fig. 2). Hydrodissection creates a potential space in the plane between the rectus muscle and the posterior rectus sheath. It is within this potential space that the tips of the rectus sheath catheter should lie to ensure the spread of local anaesthetic to the thoracic nerves.

Figure 2

Figure 2

Ultrasound image anatomy of the rectus sheath.

Clinical indications and contraindications

The main indication for utilising RSC for analgesia is for patients undergoing a laparotomy using a midline or para-median abdominal incision [3]. For smaller abdominal incisions, single short rectus sheath blocks are usually sufficient and catheters are not necessary. Absolute contraindications include patient refusal and local anaesthetic toxicity [3]. Relative contraindications include coagulopathy and sepsis [3].

Key considerations

RSCs block only the cutaneous nerves that provide somatic pain sensation. To control the visceral pain associated with laparotomies, a multimodal approach using an additional technique, such as intrathecal opioid and/or opioid PCA, must be utilised. Due to the crossover of anterior cutaneous nerves, RSC should always be inserted bilaterally. Analgesia to the lateral abdominal wall is not provided by RSC and so a multimodal approach that adds other analgesic techniques is also required if lateral abdominal drains or stomas are present. In patients with large abdominal hernias, RSCs may not be suitable because the abdominal wall anatomy can be distorted [3].

Evidence

Several small trials have been conducted that compared RSCs to thoracic epidurals in a variety of surgeries involving laparotomy [8, 9, 10, 11]. However, these had heterogenous outcomes, poor methodology and small sample sizes. Only one high-quality prospective randomised controlled trial has been conducted, the Thoracic Epidural analgesia versus Rectus Sheath Catheters trial (TERSC) [12]. In the TERSC trial, pain scores were initially better with thoracic epidurals compared with RSCs by 24 h and 48 h postoperatively; however, there was no difference in pain scores at rest and on movement, respectively. Additionally, pain scores at rest were lower with RSCs compared with thoracic epidurals at 72 h {median 4.5 [interquartile range (IQR): 0.25–13.75] versus 12.5 [IQR: 2–13]; p = 0.019}. Rates of hypotension or vasopressor dependency were higher on postoperative day 3 with thoracic epidurals compared with RSCs (49.2% versus 29.7%, p = 0.023) [12]. There was no difference in median cumulative opiate consumption by postoperative day 4 for RSCs compared with thoracic epidurals [50 (IQR: 16–81) versus 47 (IQR: 23–203), p = 0.365] [12]. No difference was reported in the postoperative morbidity score, postoperative complication rates using the Clavien–Dindo classification or the postoperative quality of recovery score between RSCs and thoracic epidurals [12]. The incidence of serious adverse events, whilst low in both groups, was three times higher with thoracic epidurals compared with RSCs (nine patients versus three patients). A nested qualitative study conducted alongside the TERSC trial reported a higher percentage of patients who rated analgesic satisfaction as excellent with RSCs compared with thoracic epidurals (46.6% versus 36.2%) [13]. Additionally, trial participants reported greater anticipatory fears and anxiety as well as negative experiences with thoracic epidural insertion compared with RSCs. A meta-analysis of four trials, including the TERSC trial, reported no differences in postoperative pain scores at 24 h and 48 h compared with thoracic epidurals. However, it did not explore other outcomes [14]. Further large prospective randomised controlled trials are needed to support the evidence from the TERSC trial.

Complications

Complications from insertion of catheters include incorrect placement, migration of catheters, injury of surrounding structures, catheter entrapment and catheter knotting [3]. Complications from the use of local anaesthetics include allergic reactions, systemic toxicity and drug errors. Reports of complications remain rare in the literature [3].

Technique

RSCs can be placed under ultrasound guidance or directly by the surgeon. The ultrasound technique allows real-time confirmation of catheter placement and enables the identification and avoidance of blood vessels [3]. However, the ultrasound technique takes longer to perform, requires additional equipment and is a more difficult skill to acquire compared with surgical insertion [3]. The surgical technique requires an open abdomen and so can only be performed intraoperatively [3]. The ultrasound technique allows RSCs to be inserted prior to surgery as well as postoperatively in the awake patient if other forms of analgesia are insufficient [3]. However, there is potential for RSCs to exit within the surgical field if performed prior to surgery [3]. A possible risk with the surgical technique is leakage of local anaesthetic into the peritoneum if a surgical opening is made in the posterior rectus sheath [3]. Although higher rates of correct placement have been reported using the ultrasound technique compared with the surgical technique [15, 16, 17], there is a lack of high-quality studies investigating outcomes of each technique, so it is not possible to suggest one option should be favoured over the other.

Delivery of local anaesthetic

Local anaesthetics can be administered through RSCs as intermittent top-ups or as continuous infusions by either electronic or elastomeric pumps. The intermittent top-up technique may promote mobility, as the patient is not connected to a pump [3]. However, there may be a greater risk of delayed or missed doses, as well as intravenous administration of local anaesthetic. One small study showed reduced opioid consumption up to 48 hours postoperatively and better pain control at rest at 24 hours postoperatively when using the intermittent bolus technique [18]. However, there is a paucity of evidence from large trials to suggest one method is superior to the other.

In the author’s clinical practice, calculated intermittent boluses of levobupivacaine (split bilaterally) are given 6–8 hourly or, alternatively, a bolus of levobupivacaine is calculated and given intraoperatively and an elastomeric pump with the appropriate dose is started 6 hourly postoperatively through a Y-connector. Alternative techniques described in the literature include intermittent boluses with ropivacaine (split bilaterally) 4–6 hourly or continuous infusions of ropivacaine per catheter [3]. There is no evidence to favour any particular regimen at present.

Conclusion

RSCs, when incorporated into a multimodal regime including PCAs and spinal analgesia, may provide a suitable alternative to thoracic epidural analgesia for patients undergoing laparotomy, resulting in non-inferior analgesia, less hypotension and vasopressor dependency, a better safety profile and the potential for higher satisfaction rates compared with thoracic epidural analgesia.

Declarations and conflicts of interest