Knotty Catheter! - An unusual complication of rectus sheath block.

Sir,

Rectus sheath block is a popular technique for post-operative analgesia for patients undergoing abdominal surgeries with midline incisions. A good analgesic effect has been reported for upper as well as lower abdominal midline incisions.[1] In this technique, the catheter is placed between the belly of the rectus muscle and the posterior rectus sheath. We commonly use an epidural set for passing the catheter bilaterally. This block can be performed either under ultrasound guidance[2] or towards the end of surgery by the surgeon under direct vision.[3]

We report the case of 28-year-old female posted for a left hepatectomy with a midline incision. Epidural insertion was attempted and later abandoned in view of difficulty in locating the epidural space. The surgery was uneventful, and towards the end of the surgery, the surgeon inserted bilateral rectus sheath catheters under direct vision prior to closure of the abdomen. Catheters were inserted upto 12 cm markings at skin. The abdomen was later closed in layers. Post-operative analgesia was managed with eight hourly top ups of 15 cc of 0.125% bupivacaine given through each of the rectus sheath catheters. No resistance to injection was encountered during administration of the local anaesthetic top ups. On the third post-operative day, the left-sided catheter was removed, but the right-sided catheter could not be removed due to some resistance encountered while removing the catheter. Interventional radiology-guided catheter removal was also tried but did not succeed. Since the use of excessive force can lead to breakage of the catheter, the patient was counselled and it was decided to remove the catheter under general anaesthesia. The patient was taken to the operation theatre and general anaesthesia was induced. The surgical incision and staples were opened and the catheter was removed. The catheter had knotted on itself [Figure 1] and was not trapped in suture line or otherwise. Johnson et al. have reported the case of rectus catheter entrapment in the surgical suture line.[4]

Figure 1

Rectus catheter knotting

The incidence of knotted nerve block catheter is as low as 0.13% as described in literature.[5] This is a very rare complication of rectus sheath catheter insertion, but there are reports that any catheter >10z cm inside has a chance of knotting.[6] Multiple techniques such as gentle tugging on the catheter, repositioning the patient to the same position as that during insertion, saline flushing of the catheter, interventional radiology and fluoroscopy-assisted removal and surgical exploration are some of the techniques described in literature for catheters which are difficult to remove.[6]

The purpose of reporting this case is to make the readers aware of this rare complication and its treatment which may require surgical intervention after all the other modalities have failed. We suggest that as this procedure is under direct vision, an effort should be made to palpate the catheter during insertion and avoid threading excess length of the catheter inside the fascial plane. Forceful removal of the catheter should not be attempted whenever resistance is encountered as this may lead to catheter breakage.

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Conflicts of interest

There are no conflicts of interest.