Complications of Epidural Failure During Knee Surgery

Providing an epidural injection into the spinal area can allow a patient to remain awake during knee surgery. Feeling pain due to the anesthesia not working--due administration problems, however, shouldn’t be one of the complications of surgery.

Epidural Anesthesia

• Epidural anesthesia is an injected anesthesia placed into the body through the spinal area of the back. It is commonly used during surgeries that involve childbirth, the hips and the legs (including knees). When administered correctly and when there are no complications, an epidural allows the patient to remain awake during the procedure but feel no pain.

  A needle is inserted into the spinal area during an epidural, allowing the insertion of a catheter into the targeted area of the lower back before the needle is then removed. The catheter then can be used to supply pain medication, as needed, throughout the surgery instead of injections having to be administered repeatedly.

Epidural and Knee Surgery

• Some surgeons choose to use an epidural anesthesia to numb the lower body area of the patient in preparation for knee surgery. Use of an epidural is not without complications, though, according to Dr. Leon Visser of the Department of Anesthesiology at the University of Michigan Medical Center. Those complications can include failure of the epidural block.

Complication: Failure of Epidural

• The epidural block can fail to deliver the needed pain relief during surgery for several reasons, according to Dr. Visser. The inexperience of the individual administering the epidural is the single most important reason for failure.

  In addition, there is a certain amount of resistance when the needle is inserted into the epidural space. Once the needle reaches the epidural space, though, the resistance is reduced. A false reduction in resistance might occur, however, leading to catheter insertion outside the epidural space, which would result in the epidural not being delivered to the nerve area to be deadened.

Partial Failure Complication

• Segmental spacing, a partial failure of the epidural, is believed to be the result of anatomical differences between individuals' epidural space. This results in the epidural not reaching all of the nerve endings that should have been deadened by the anesthesia prior to the surgical process, according to Dr. Visser.

  Some nerves, then, are not affected by pain during the knee surgery, but others are, resulting in pain for the patient and the likelihood that other pain-reducing measures need to be undertaken to conclude successful surgery.

Unilateral Blockade

• When the epidural space is septated (one side separated from the other), the epidural's effect can be blocked on one side. If undetected prior to surgery, this could result in pain during surgery on one side of the patient's knee. Sometimes having the patient turn to lie on one side during surgery can help spread the pain medication to needed areas, according to Dr. Visser.