Asymptomatic pneumomediastinum resulting from air in the epidural space -a case report-
A hospitalized 56-year-old male patient diagnosed with hepatocellular carcinoma was under the care of the Digestive Internal Medical Department. In order to control the patient's pain level, the Digestive Internal Medical Department requested joint treatment from our pain clinic. The patient was 160.5 cm tall and weighed 54.5 kg. At the time of arrival at our pain clinic, the patient's blood pressure was 145/90 mmHg and the heart rate was 68 beats per min (bpm). The patient complained of general weakness and right flank pain. Results of the laboratory examination showed an AST and ALT of 106 and 83, respectively, and no evidence of bleeding. Liver computed tomography (CT) and positron emission tomography (PET) CT taken one week prior revealed a 1-9 cm sized multiple mass and a right portal vein thrombosis in the liver parenchyma. On a simple chest X-ray, no active lesion was seen. Pulmonary function test (PFT) was not performed as a part of this procedure. The patient's main symptoms were back pain and flank pain limited to the T7 and T8 dermatome level. In order to determine the pain level, epidural block was performed one time at the T7 and T8 level. A consent form was signed by the patient after a detailed explanation of the medical procedure and its possible complications. The epidural block was not performed with the aid of a C-arm guide. In the left decubitus position, 6 ml of 1% lidocaine was administered as a local anesthesia after betadine was used to cleanse the expansive back region. The paramedian approach was executed using a 22-gauge Tuohy needle at the T7-8 level. Using a Tuohy needle connected to a syringe filled with 5 ml of air, intermittent pressure was applied in order to locate the epidural space using the LOR technique. On the first attempt, approximately at a 5 cm depth, the lamina of the vertebra was contacted. After the needle was slightly retracted, the needle was advanced towards the cephalad slightly, and at about at 5.5 cm depth, the LOR was not definitive. Thus, we applied pressure approximately 4 times into the syringe which was fixed at the same depth. After that, one more attempt was made. At the same depth, a slight LOR was continuous, and therefore, we came to the conclusion that it was the epidural space. Following the injection of 8 ml of 0.8% mepivacaine and 20 mg of triamcinolone, the patient stabilized after being in the supine position for one hour. After one hour, the patient was moved to the ward. His visual analog scale decreased to 3/10 from 7/10. The patient's blood pressure was 130/93 mmHg and his heart rate was 90 bpm. Chest discomfort and dyspnea were not observed and there were no other unusual impressions. Three hours after the patient was transferred to the ward, a PET-CT was performed in order to prepare the patient for Transarterial Chemoembolization (TACE). The results of the PET-CT revealed a new occurrence of pneumomediastinum in addition to the liver mass and portal vein thrombosis observed one week before (). The position of the pneumomediastinum was extended from T10 (the site where the epidural block was performed) to the C2 epidural space. In addition, air was observed in the paraspinal muscle and epidural space (). After the patient was informed of the pneumomediastinum, the patient was supplied with oxygen at 2 L/min by a nasal cannula and observed closely in the ward. The patient did not have any unusual complaints and was stabilized in bed and a chest CT taken 7 days later showed no signs of pneumomediastinum and pneumothorax.