LARS P. WANG, JOHN HAUERBERG AND JES F. SCHMIDT
National University Hospital, Copenhagen, Denmark
Anesthesiology, 91: 1928–1936, 1999
Epidural analgesia is often used for postoperative pain relief. Two serious complications, the spinal epidural hematoma and the spinal epidural abscess, may result in severe morbidity. This study estimated the incidence of epidural abscess after epidural analgesia in Denmark during a 1-yr period and evaluated the overall use of epidural analgesia during the same time. Treatment and outcome in patients with spinal epidural abscess were also analyzed.
All anesthetic departments in Denmark were invited to participate in the prospective study. A questionnaire was sent to participating departments; this questionnaire was to be completed when a patient developed an epidural abscess after epidural analgesia. Of 59 departments in Denmark, 46 participated in the study; 12 were university departments and 34 were nonuniversity departments. A total of 17,372 epidural catheters were used during the 1-yr period; 68% of the epidural procedures were performed at the university departments.
Data from 12 patients with possible epidural abscess formation were collected. Nine had developed a true spinal epidural abscess, two had subcutaneous infections, and one experienced sequelae from a misplaced epidural catheter.
The nine cases of epidural abscess were evaluated. The catheters remained in situ for a mean of 11 days and a median of 6 days. Five had thoracic catheter placement and four had a lumbar epidural catheter. In the 9 patients, 67% received epidural analgesia for perioperative pain relief, 22% for cancer pain, and 11% for trauma-related pain. Six patients had received low-molecular-weight heparin as thromboprophylaxis before catheterization. Symptoms and signs of meningitis were found in 11% of the patients, 56% of the patients were febrile, and 67% had signs of local infection. Localized back pain was reported by 67% and 78% developed neurologic disturbances such as lower limb paraplegia, urinary or fecal incontinence, or irradiating pain.
The time from appearance of the initial symptoms of epidural abscess to the time diagnosis was confirmed varied from 1 to 32 days. Staphylococcus aureus was isolated in 6 patients, coagulase-negative cocci in 1 patient, and no bacteria in 2 patients. Bacteremia was diagnosed in 2 patients. All received IV antibiotics.
Seven patients with neurologic deficits had neurosurgical decompression of the spinal cord within 24 hr of verification of the diagnosis. Four of these patients developed persisting neurologic deficits. The risk of persisting neurologic deficits was 1:4,343 catheters. Although there is little doubt that epidural analgesia is an effective method of pain treatment, it is the responsibility of each anesthesiologist, together with the patient, to agree on the best and most acceptable method of postoperative pain relief.
Seventy-eight percent of Danish anesthesia departments responded to this survey of the incidence of epidural abscess associated with epidural analgesia. Consistent with other studies, the authors report an incidence of epidural abscess of 1:10,000 patients receiving epidural analgesia. The results are also consistent with practitioners’ understanding of epidural abscess, i.e. 1) the risk for epidural abscess appears to increase with the duration of epidural catheterization; 2) the majority of the patients with epidural abscess were immunocompromised; and 3) the longer the period from diagnosis to intervention, the worse the neurologic outcome. Perioperative anticoagulation therapy was involved in 8 of 9 cases reported in this survey. No differentiation was made between epidural abscess or an infected epidural hematoma in these cases.
Although the incidence of epidural abscess is low, the prudent practitioner will certainly recognize the need to weigh the risk of abscess in the immunocompromised patient versus the benefit to be derived from this therapy. Further, in patients who appear to be at high risk for epidural abscess, it is important to maintain a high level of vigilance to allow for rapid diagnosis and treatment of the abscess.
Ferne B. Sevarino M.D.