CONTINUOUS three-in-one blockade is widely used for providing postoperative analgesia after knee surgery. Distinct serious complications have been described after femoral nerve block: neurologic injury as well as hematoma compressive and epidural anesthesia. 1–2We report a case of psoas abscess complicating a continuous three-in-one blockade.
Case Report
A 35-yr-old woman, American Society of Anesthesiologists physical status 1, was admitted for a knee arthroscopic arthrolysis. Before induction of anesthesia, a femoral catheter was placed aseptically. The anesthetist wore a cap, a face mask, and sterile gloves. The skin was prepared with 1% polyvidone iodine and was draped with sterile drape. Continuous three-in-one blockade was performed following Winnie et al . landmarks. 3An insulated short-beveled needle with an 18-gauge cannula (Mini Set®; Pajunk, Geisingen, Germany) was inserted cranially until muscle contraction in the quadriceps was observed. The needle was removed, and a 20-gauge multiorifice catheter was then easily placed. After a negative aspiration test, 20 ml of ropivacaine, 0.75%, was injected. A micropore flat bacterial filter 0.2 μm (Portex LTD, Hythe, Kent, England) was connected to the hub of the femoral catheter, which was secured with a transparent adhesive dressing.
Postoperative analgesia was provided by a continuous infusion of ropivacaine, 0.2%, at 8 ml/h on the femoral catheter. Four days after surgery, the femoral catheter was removed. The nurse noted no evidence of superficial infection at the catheter insertion site. On the next day, the patient reported pain in her left lower quadrant associated with fever and an elevated leukocyte count. Four days after the catheter was removed, the patient remained febrile and the abdominal pain persisted. A pelvic echograph showed a psoas mass. Abscess formation was treated with computed tomographic scan-guided percutaneous puncture (fig. 1). The copious amounts of pus subsequently indicated Staphylococcus aureus . The infection was treated with a 1-month course of antibiotics, after which a second computed tomographic scan showed no recurrence of the psoas mass.
Discussion
The main infectious complication reported after a regional nerve block technique is the uncommon but potentially deleterious epidural abscess. 4Recently, it was shown that after 48 h, 57% of femoral nerve catheters had positive bacterial colonization; however, no patient developed an abscess. 5In our patient, a culture was not performed on the catheter because on the day of removal the patient reported no discomfort. Yet S. aureus found with computed tomographic scan puncture is the most common causative organism cultured from epidural abscess after epidural anesthesia. 6Pyogenic psoas abscesses are most often associated with vertebral osteomyelitis or Crohn disease. 7In our patient, the abscess probably resulted from catheter colonization at a superficial site and subsequently wicked the infection from the skin to the psoas space.
This case illustrates the importance of the golden aseptic rules during puncture and catheter insertion for regional anesthesia. In any patient who shows an infectious syndrome and has or has had a continuous nerve block, the possibility of a complication of regional anesthesia should be considered until proof of the contrary, even if the patient had no evidence of superficial infection at the catheter insertion site.
