Epidural block anesthesia is performed not only for anesthesia of surgical operations but also for pain control after operations and treatment of chronic pains. It is known that its complications rarely occur, but haematoma and spinal nerves injuries, as well as neuromuscular injuries, might break out.
Staats et al. [2
] once reported that spinal stenosis occurred due to a reactive epidural clot surrounding a catheter fragment which was cut by 1.5 cm in the process of catheter insertion and retained inside the epidural space; after removing the catheter fragment and injured tissue, symptoms of the patients were improved. Bonica et al. [3
] reported 3 cases of retaining epidural catheter fragments inside the epidural space. Reports say that 2 of them required surgical removals while the other did not because no complication was detected.
] described that due to the recent technology development, it is hard to damage an epidural catheter and an epidural block anesthesia needle tip can be broken only with power more than 1-2 kg. Accordingly, they argued that main culprit of damage is a defect in the process of manufacturing or mistakes of the operating surgeon. Abou-Shameh et al. [5
] reported the case that although a catheter was successfully inserted during a spinal-epidural joint block, a dural puncture was difficult because the needle for spinal anesthesia was short due to the condition of extreme obesity. In that case, the operating surgeon tried spinal anesthesia at the lumbar space one segment lower, but after a number of trials, the spinal anesthesia needle was removed. After the removal, the distant part of the needle disappeared by about 5 cm, and the cut needle tip was removed by performing surgical operation. They reported that the case of the broken needle tip occurred twice in 20 years, showing an occurrence rate of 1: 5,000.
Lumbar spinal stenosis is the disease in which the narrowed spine presses the spinal cord. According to Kirkaldy-Willis et al. [5
], facet joint suffers facet joint syndrome and synovitis from early hypofunction, adding more articular capsules, and the joint becomes unstable so that the vertebral body transfers to the front. Repeated stimulus from instability after the transmission causes thickening and osteophyte formation restabilizing spinal segments. However, both thickened structures at the rear and bulging or projecting intervertebral disc at the front suppress the driving region of the nerves, causing spinal stenosis [6
Mostly, the cause of spinal stenosis is a degenerative change of the spine due to aging. For a congenital cause, achondroplasia leads to severe stenosis due to a short pedicle, bulged facet joint, and lamina, and this becomes a cause of early spinal stenosis. Also, the spinal stenosis can lead to the second transmutation of spinal stenosis [6
]. Among secondary causes, iatrogenic stenosis can occur after laminectomy or spinal fusion. Moreover, as mentioned earlier, there is a case reported about spinal stenosis occurring by a foreign body inside the vertebral space.
The patient in this case is 39 years old, so it is unlikely to be a degenerative spinal stenosis from aging. Moreover, while there is no special diagnosis for other spinal segments, an MRI scan of the right facet joint in which the needle tip was detected showed a second transmutation including degenerative changes and thickening of the neighboring ligamentum flavum. Against the backdrop, it is assumed that the patient had a retained needle tip broken during an epidural block procedure, then the second transmutation occurred around the right facet joint, leading to spinal stenosis.
A broken needle tip can occur from a manufacturing problem, rather than from operation techniques. For an ideal needle for epidural block, Collier [4
] argue that it should be sufficiently sharp to cut spinal ligaments and simultaneously be sufficiently dull so as to not perforate the dural. Chin et al. [7
] reported the case when the needle tip and hub of spinal anesthesia injection detached from each other. They assumed that careless manipulation, repeated usages of the spinal needle, and the obesity of the patient were the main culprits, and insisted that an epidural block should be carefully operated under accurate knowledge of anatomy. When facing resistance during the insertion of a needle or catheter for epidural block anesthesia, immoderate proceeds or giving excessive power should be prohibited. Also, after finishing an operation, the needle should be checked. The case of spinal stenosis due to the fracture of an epidural block catheter retained inside the epidural space occurred when the tip of the catheter was cut during pulling the catheter back because of resistance in the process of insertion [2
]. Chin et al. [7
] also highlighted the careful operation of epidural block anesthesia. Blanchard et al. [8
] described the case where a patient complaining of radiating pain required a surgical operation due to a retained catheter during the insertion process of a catheter for epidural block anesthesia. Blass et al. [9
] introduced the case where the retained catheter was removed through lumbar laminectomy since it was impossible to remove it manually because the catheter was stuck and twisted around the ligamentum flavum. In most cases, however, a catheter being retained inside the epidural space does not cause problems [10
]. If part of the catheter during epidural block anesthesia is retained inside patients, it is not normally removed. For rare cases accompanying neurologic symptoms or second transmutations, surgical operations might be required.
When operating epidural block anesthesia, accurate knowledge of anatomy should be a prerequisite to avoid careless manipulation. Also, operators should check whether the tip of needle or catheter is broken or not with the naked eye, and when the retained fracture is doubtful, they should consider X-ray scanning. So far, there have been reports about spinal stenosis due to retained fracture of a catheter inside the vertebral space. However, there is none about the case describing spinal stenosis from retained catheter fracture inside the spinal space. Therefore, it is considered that additional data collection and monitoring are required.