Continuous wound infiltration

History

Continuous wound infiltration first appeared on the market in the late 1990s when a US company (I-Flow Corporation) found a way to evenly spread and continuously infiltrate a local anesthetic, via a specially designed multi holed catheter, inside the wound, to enable post-operative pain treatment.

The benefits of wound infiltration are quite prominent which is the reason why "single shot" wound infiltration had already been done for several decades. The limiting factor of the single shot approach has always been the half-life period of the local anesthetics which would not allow a long term post-op pain treatment.

Technique

A local anesthetic is administered into the wound with a specially designed, multi-holed catheter. The catheter allows for even spread throughout the entire area of the wound, depending on the size of the catheter.

The surgeon places the catheter during surgery shortly before closing the surgical incision. For best catheter placement and nerve blockage, the catheter must be located as close as possible to the nerve. Tunneling should be applied if a distal infiltration of the adjacent nerve root is preferred.

For thoracic and abdominal surgeries, the surgeon will place the catheter superior to the respective fascias. For thoracic surgeries, the catheter goes superior to the pleura. For all type of abdominal surgeries the catheter should be close to the peritoneum. A recent systematic review showed that deep wound catheters (placed pre-peritoneally or in the transversus abdominis plane), provide better pain control than subcutaneous wound catheters after abdominal surgery.

After being placed, the catheter is connected to an elastomeric pump that ensures a constant delivery of the anesthetic and also serves as the drug container. Depending on the flow rate and the pump size, one pump can provide continuous wound infiltration for several days.

Outcomes

CWI is considered as an effective alternative to other regional anesthetic techniques such as peripheral nerve blocks and spinal-epidural anesthesia. It is especially applicable where those techniques are contra-indicated, such as in patients using potent coagulants.

Besides, some patients might prefer an alternative to epidural analgesia because of epidural-related side effects. Epidural analgesia may lead to serious neurological complications (epidural haematoma and abscess, with an incidence of one in 1000–6000 for thoracic epidurals) and need for preoperative placement in awake patients, considered as cumbersome by many patients, sometimes leading to refusal.

The outcome in most cases is beneficial for the patient because of a faster return to normal body functions, less pain, faster rehabilitation and less side effects. CWI offers the opportunity to significantly minimize the use of narcotics during post-op pain management and reduces the side-effects (post-operative nausea and vomiting) that come with opioids. Also, CWI has been shown to provide more excellent satisfaction scores compared to alternatives.

References

References

1. (February 2019). "Preperitoneal or Subcutaneous Wound Catheters as Alternative for Epidural Analgesia in Abdominal Surgery: A Systematic Review and Meta-analysis". Annals of Surgery.
2. (2008-12-01). "Effectiveness and safety of postoperative pain management: a survey of 18 925 consecutive patients between 1998 and 2006 (2nd revision): a database analysis of prospectively raised data†". British Journal of Anaesthesia.
3. (2007-03-21). "Major complications of epidural analgesia after surgery: results of a six-year survey: Epidural complications". Anaesthesia.
4. (October 2004). "Severe neurological complications after central neuraxial blockades in Sweden 1990-1999". Anesthesiology.
5. (2016-10-01). "Continuous wound infiltration versus epidural analgesia after hepato-pancreato-biliary surgery (POP-UP): a randomised controlled, open-label, non-inferiority trial". The Lancet Gastroenterology & Hepatology.
6. (December 2007). "The influence of race and socioeconomic factors on patient acceptance of perioperative epidural analgesia". Anesthesia and Analgesia.
7. (September 2008). "Factors associated with the choice of delivery without epidural analgesia in women at low risk in France". Birth (Berkeley, Calif.).
8. (February 2019). "Preperitoneal or Subcutaneous Wound Catheters as Alternative for Epidural Analgesia in Abdominal Surgery: A Systematic Review and Meta-analysis". Annals of Surgery.