Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

Analysis of thoracic epidurography and correlating factors affecting the extent of contrast medium spread

BACKGROUND: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. METHODS: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. RESULTS: The mean number of vertebral segments evaluated by contrast medium was 7.9 ± 2.2 using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = −0.311, P < 0.05). CONCLUSIONS: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of 7.9 ± 2.2 spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

The Correlation between Caudal Epidurogram and Low Back Pain

BACKGROUND: The common causes of lower back pain with or without leg pain includes disk disease and spinal stenosis. A definitive diagnosis is usually made by means of magnetic resonance imaging (MRI), but treatment is often difficult because the MRI findings are not consistent with the symptoms of the patient in many cases. The objective of this study was to observe the correlation between the patterns of epidurography performed in patients having lower back pain with or without leg pain and the position or severity of the pain as subjectively described by the patients. METHODS: The subjects of this study were 69 outpatients with lower back pain with or without leg pain who visited our clinic and complained of predominant pain on one side. We performed caudal epidural block using an image intensifier. A mixture of the therapeutic drug and the contrast agent (10 ml) was injected to observe the contrast flow pattern. The patients who complained of predominant pain on one side were divided into the left side group and the right side group. A judgment of inconsistency was made if the contrast agent flowed to the side of the pain, while a judgment of consistency was made if the contrast agent flowed to the opposite side of the pain. The degree of the drug distribution was evaluated by counting the number of cells to which the contrast agent's flowed for evaluating the correlation between the contrasted cell and the severity of pain (one group or = VAS 8) the degree of the contrast agent's contrast was evaluated by dividing and counting an image into 15 cells (the left, right, and middle sections at each level of L4, L5, S1, S2, and S3). RESULTS: Thirty out of the 69 patients who had laterality in pain, that is, those who complained of predominant pain on one side, showed that the laterality of the pain and the contrast agent flow was consistent, while 39 patients showed that the laterality was inconsistent (P: 0.137). The evaluation of the correlation between the pain and the contrast agent flow showed that the mean number of contrasted cells was 9.0 +/- 2.2 for the 46 patients in the group with a VAS of 7 or lower and 6.5 +/- 2.0 for the 23 patients in the group with a VAS of 8 or higher, indicating that the former group showed a significantly greater number of contrasted cells (P < 0.001). CONCLUSIONS: This study, conducted with patients having lower back pain with or without leg pain, showed that the contrast flow pattern of caudal epidurography had a significant correlation with the severity of the pain but not with the laterality of the pain.

An Analysis of Pattern of Transforaminal Epidurography / 대한통증학회지

BACKGROUND: A transforaminal epidural steroid injection has been used for the treatment of radicular arm or leg pain, which has the advantage of ventral epidural spreading compared to either an interlaminar or caudal approach. However, several factors are known to affect the epidural spread pattern of contrast dye; therefore, the injected medication can not be delivered to the target site. The objective of our study was to observe any differences in the contrast flow patterns according to several factors. METHODS: A total of 34 epidurographies in 29 patients, who underwent fluoroscopically guided transforaminal epidural steroid injections, were evaluated. After confirming the location of the needle tip within the anterior superior aspect of the neural foramen in the lateral view, and at the 6 o'clock position to the pedicle in the anteroposterior view, 2 ml of contrast dye was injected. The contrast flow patterns of ventral, ventral and dorsal, and dorsal epidural filling were analyzed, according to age, gender, magnetic resonance imaging finding and history of previous back surgery. RESULTS: Ventral contrast flow occurred in 30 out of the 34 epidurographies (88%). Both ventral and dorsal contrast flow patterns were observed 13 out of 16 (81%) patients in the older age group. Also, both ventral and dorsal contrast flow patterns were observed in 16 out of 18 (88%) patients with spinal stenosis. CONCLUSIONS: Transforaminal epidural steroid injections, performed under fluoroscopy, provide excellent nerve root filling and ventral epidural spreading. Patients with spinal stenosis or an old age have both ventral and dorsal epidural spreading patterns.

Clinical and Electrodiagnostic Findings of Failed Back Surgery Syndrome

OBJECTIVE: To analyze the clinical and electrodiagnostic findings of patients with failed back surgery syndrome after lumbar disc operation. METHOD: We investigated 28 patients with back and/or lower limb pain and weakness who were underwent lumbar spine operation. Seven patients who had undergone surgery due to spinal infection or fracture were excluded. Twenty-one patients included 7 female and 14 male patients with ages 20~63 years, and the mean age was 44.4 years. The following data were evaluated: clinical symptoms, neurological examination, duration from operation to first visit, preoperative diagnosis, operation number and site, electrodiagnostic studies, radiologic studies (simple radiographs, epidurography, CT, MRI), and psychological evaluations (SCL-MPD). RESULTS: The time of the visit after the operation varied between one month and 15 years (mean 48.5 months). Electrodiagnostic study revealed lumbar radiculopathy in 18 patients and the most common level was at the fifth lumbar root. All eight patients who undergone epidurography showed filling defect or indentation. Psychologic evaluations were performed on five patients and they revealed high scores in depression and somatization. CONCLUSION: Clinical and electrodiagnostic findings of lumbar radiculopathy, abnormal epidurographic findings and psychological results after lumbar disc operation were related to the causes of failed back surgery syndrome.

Epidurographical Spreading Patterns of Successive Small Volume Caudal Epidural Injections in Chronic Low Back Pain / 대한마취과학회지

BACKGROUND: A volumetric caudal epidural steroid injection has been advocated to facilitate the delivery of medications to a lesion site. This study was aimed to examine the actual spreading patterns of this technique, using an epidurogram. METHODS: A total of 32 patients with chronic low back pain with a radiculopathy of various causes (degenerative spondylosis, herniated nucleus pulposus, spondylolisthesis, and spinal stenosis) were included. A volumetric caudal epidural injection of a 10 ml mixture of contrast medium 5 ml, 0.5% bupivacaine 1 ml, triamcinolone 1.5 ml (60 mg) and normal saline 2.5 ml was performed. Immediately after the cessation of the first spread, the subsequent solution of another 10 ml of contrast medium 5 ml, 0.5% bupivacaine 1 ml and normal saline 4 ml was injected. This procedure was repeated serially until the total volume equaled 50 ml. Continuous fluoroscopic imaging was obtained after each injection. RESULTS: Average time taken to complete the study was 37 seconds per every 10 ml. The spreading levels of the mixture were distributed mainly at the mid to lower lumbar area in the majority of the investigated patients. During the subsequent injections, these levels did not increase significantly. CONCLUSIONS: We concluded that the multiple small volume caudal epidural injections retraced their own tract repeatedly. This was thought to be due to the minimal resistance in the cephalad direction, anatomic variations and the Starling effect of epidural space.

Anatomy of Human Epidural Space using CT-epidurography / 대한마취과학회지

The anatomy of the human epidural space was demonstrated in 8 patients by computed tomography (CT) examinations performed after epidural injection of water soluble radiographic contrast material into the L3-4 epidural space via Tuohy needle. The examinations showed the posterior epidural space to be divided by the plica mediana dorsalis and an additional transverse connective tissue plane. The compartmentalized nature of the space may be, at times, responsible for entrapment and coiling of epidural catheters, despite the satisfactory technical performance of catheterization for epidural anesthesia. All patients demonstrated a great amount of fatty tissue within the junction of the posterior midline epidural connective tissue structures, producing a triangular-shaped structure which might be an impediment to catheterization. The posterior epidural space is more easily filled with contrast media than the anterior epidural space. We also measured the depth of epidural space. The posterior epidural space was 2-6 mm deeper than the anterior epidural space. At the thoracic spine, the depth of the posterior epidural space was about 1-2 mm and the anterior space was under 1 mm or revealed trace. At the lumbar region, the depth of the posterior epidural space was about 4-7 mm. Air bubbles were noticed in the epidural space, especially around intervertebral foramen; therefore, it was suggested that the air bubbles can produce incomplete analgesia along the nerve roots.