Peri-incisional catheters through open surgical wound in converted nephrectomies: A novel modification of transverse abdominis plane block.

Dear Editor,

Whenever a laparoscopic nephrectomy gets converted to open surgery, it requires additional measures to improve pain control. A peri-incisional catheter through an open wound is a simple, novel, and effective technique of transverse abdominis plane (TAP) block for postoperative pain management.

We have placed dual peri-incisional TAP catheters through the surgical wound in 3 cases. A 16G Tuohy needle is introduced 2 inch above outer edge of the wound on either side; the needle is passed between the internal oblique and transversus abdominis muscle/aponeurosis, guided by the surgeon. As the needle comes out of the wound, we thread the catheter till it comes out of the distal end of needle [Figure 1]. The needle is withdrawn and the catheter is brought out for 1–2 cm and flushed with 5 cc saline. Any pericatheter leak is checked and suture fixation is done. Fixation is reinforced with a catheter clamp [Figure 2]. Postoperatively, the patient receives 0.1% bupivacaine infusions at 6–8 ml/h for 3 days and morphine, a patient-controlled analgesia as rescue. The average pain scores on day 1 were 3/10 at rest and 5/10 on coughing.

Figure 1

Solid horizontal arrow show Tuohy needle with catheter coming through transverse abdominis plane fascia (vertical down arrow) horizontal lined arrow show transversus abdominis, internal oblique, and external oblique muscles from top to bottom

Figure 2

Lined horizontal arrow show anterior peri-incisional catheter, solid horizontal arrow show posterior peri-incisional catheter, and solid up arrow show subcostal line

Various techniques for TAP block have been performed by anesthetists[12] alone or with surgeons’ assistance.[3] Differential dermatomal coverage was observed in classic approach of Rafi[1] (T6–L1 dermatomes) and Hebbard[2] oblique subcostal approach (T7–T12 dermatomes), which could be due to fact that upper and lateral TAP compartments do not appear to communicate with each other, as confirmed by magnetic resonance imaging analysis,[4] and by contrast enhancement.[5]

Our technique is partially open, relatively simpler, and a novel simulation of combined subcostal and midaxillary techniques of TAP block in which catheters were placed by penetrating the needle into the abdominal wall.

Our technique differs from that of the Børglum et al.[6] (4-point single shot ultrasonography [USG]-guided bilateral posterior and oblique subcostal blocks). First, our blocks are performed intraoperatively (vs. their postoperative blocks). Second, it is performed without ultrasound assistance. Third, there is no fixed landmark for catheter insertion; site and number of catheter insertion depends on the extent of incision and can be changed according to length and site of incision. Instead of single shot injections, our catheters provide continuous infusion of drugs and better pain relief.

Our technique can prove a sensible substitution since there is no need of USG/detailed knowledge of abdominal wall anatomy/skilled personnel to advance the needle inplane.[2] Inserting the catheters after wound closure might face the technical difficulties with inability to follow the TAP because of limitations in needle movement, having a needle too short to pass along the subcostal oblique line, and a distorted anatomy due to previous surgery, air in the tissues, edema, and obesity.[2] Further, anatomical distortions of the planes (hydrodissection by injecting in wrong planes or needle displacement by the variable pressure of the transducer probe) is not the potential problem in our technique. Strict aseptic precaution is required to prevent surgical site infection, also injury to catheter or its dislodgement at the time of surgical wound closure should be taken care. Although this novel technique is reliable, simple to perform but needs further studies to substantiate the results.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.