A case study of spinal nerve compression caused by a small amount of epidural pneumatosis

Abstract

This case describes a patient with painless childbirth in anaesthesia recovery, who suffered from spinal nerve dysfunction because of the presence of a small amount of epidural gas. Although the patient eventually recovered, this reminds us that timely observation and treatment is important in clinical epidural anaesthesia.

Case report

A 27-year-old female patient with 35+ 5  weeks of pregnancy was admitted to a hospital due to irregular lower abdominal pain for 2+ days. Nothing special was found in the medical history. The regular antenatal examinations during pregnancy showed normal results. The routine blood parameters were as follows: HGB = 102 g/L, PLT = 134×109/L; BT/CT: PT = 13.0 s, APTT = 28.2 s. Painless delivery was decided as the cervix opened to about 6 cm after 8 h of admission to the hospital. Epidural anaesthesia was performed by puncture at the L₂-L₃. The puncture needle was pierced into the skin for 4 cm and passed through the ligamentum flavum. Then about 3 mL of air was pushed in to verify the position of the puncture needle, which was followed by inserting a 5-cm-long epidural catheter. This puncture was quite smooth with no discomfort as mentioned by the patient. About 5 mL of 1% lidocaine was administered epidurally as the test dose, and the block level of the patient was at T₁₀ when tested after 5 min. Next, the epidural anaesthesia pump (Smiths Medical ASD, Inc., Mexico) was connected to perform continuous pumping of the analgesic for painless delivery. The analgesic consisted of a mixture of 100 mg ropivacaine (AstraZeneca), 200 μg fentanyl, and normal saline. The initial dose was 10 mL, and the background dose was 8 mL/h. The patient performed vaginal delivery after 3 h of epidural. The epidural catheter was removed after the delivery of baby. The analgesia showed good effect during the delivery. The muscular strength of two lower limbs was normal as the patient was able to get out of bed after 2 h of the delivery to perform self-urination. However, she suffered from uroschesis, which aggravated after 4 h of urination. At midnight, the indwelled catheter was placed. On the next day, the patient suffered from limited lower limbs movement. At this stage, the senses of the lower limbs were normal, the muscle strength of the left thigh was at Level I, and that of the right thigh was at Level II. Dorsiflexion was found in both feet, with plantar flexion in normal condition, and no obvious pathological sign. CT showed there was intraspinal pneumatosis at L₁-L₃ disc levels with a volume of 2–3 mL. Punctate gas density shadows at low density was displayed (Figure 1). The patient mentioned that the lower limbs suddenly reactivated after she was removed from the CT bed. Thus, magnetic resonance imaging (MRI) was performed immediately. The MRI result showed that there was no pneumatosis at the segments of concern. According to the physical examination, the lower limbs of the patient were free to move, and the muscle strength and physiological reflex were in normal condition. Then, the patient was successfully discharged on Day 5 after delivery.

Figure 1.

CT results. Epidural gas at L₁ -L₂ disc level, and what the arrows point are all gases.

Discussion

There are rarely any reports on neurological dysfunction due to spinal cord compression caused by epidural pneumatosis.^1,2 Based on the medical history and imaging data, this case was interesting to investigate. Previous reports have indicated that the repeated puncture during epidural anaesthesia is common. Furthermore, epidural pneumatosis in a large volume was usually found when the patient could not recover from the anaesthesia. In this case study, the author performed the puncture under normal operation, and succeeded the first time. There was small epidural pneumatosis (2–3 mL according to CT), and we did not find the simple motor dysfunction of both thighs until 24 h after the patient recovered from the anaesthesia completely, which is quite rare. We supposed that the motor dysfunction may have been caused by the aggregation of free epidural gases into larger bubbles when the patient was lying in bed and the large bubbles may have compressed the anterior roots of spinal cord. During CT examination, the change of body position may have led to cracking of gas bubbles and accelerated their fusion, diffusion and absorption into the adipose tissue in the epidural space relieving the clinical symptom quickly.

Although the patient in this case and other patients with neurological symptoms caused by epidural pneumatosis as reported previously recovered finally, it is impossible to eliminate the possibility of permanent neurological damage caused by epidural pneumatosis.^3,4 We suggest that normal saline might be useful as a substitute for air to detect the change of resistance during hiss test for epidural anaesthesia. For any patient with difficulty to puncture, the operation can be performed according to the actual condition, and other anaesthesia modes might be used when necessary. Once there is any symptom of compression, it is required to examine and treat immediately to relive the compression as soon as possible to avoid any complications of permanent neurological damage.