The caudal approach to the epidural space involves the use of a Tuohy needle, an intravenous catheter, or a hypodermic needle to puncture the sacrococcygeal membrane . Injecting local anaesthetic at this level can result in analgesia and/or anaesthesia of the perineum and groin areas. The caudal epidural technique is often used in infants and children undergoing surgery involving the groin, pelvis or lower extremities. In this population, caudal epidural analgesia is usually combined with general anaesthesia since most children do not tolerate surgery when regional anaesthesia is employed as the sole modality.
Methotrexate is given weekly as an intramuscular injection of 15 to 25 mg. Side effects are rare and include leukopenia and hypersensitivity interstitial pneumonitis. Hepatic fibrosis is the most severe potential sequela of long-term therapy. Patients with concomitant alcohol abuse and/or morbid obesity are more likely to develop hepatic fibrosis and therefore should not be treated with methotrexate. It is prudent to obtain a baseline chest radiograph and to monitor complete blood count, liver function and renal function every two weeks until the patient is receiving oral therapy, and every one to three months thereafter. Before methotrexate therapy is initiated, the risks of treatment and the possible need for a liver biopsy should be discussed with the patient.