Epidural insertion simulator of higher insertion resistance & drop rate after puncture

Accidents such as dural puncture remain one of the problems of epidural anesthesia, and unskilled doctors can repeat such accidents. The purpose of the current research was to provide a new simulator for epidural insertion training. No reference data regarding the resistance force used when inserting a needle into patients have been reported. A comparative study was conducted to aid in the development of a new simulator. Pork loin (n=5) were employed as a substitute for patients. Thickness was set at 2 cm so as to improve the reproducibility. The authors took the conventional simulator apart, and picked a block as an analogue of muscle and ligamentum flavum. A new simulator was made of a melamine foam resin block and a latex rubber sheet. An epidural needle fixed on a motorized stage was inserted at the speed of 2 mm per second. The reaction force was measured while the needle was inserted into each specimen. Waveform of the pork loin exhibited two slopes of different inclines up to peaks and then falls after puncture. The conventional simulator showed a simple increase up to peak and a slow fall after puncture. In contrast, the new simulator showed two slopes up to peak and then a sudden fall after puncture. The insertion resistances were 2.5 N/s for the porcine, 0.8 N/s for the conventional and 2.1 N/s for the new simulator. The drop rates were 5 N/s for the porcine, 0.6 N/s for the conventional and 24 N/s for the new simulator. The higher insertion resistance and drop rate for the new simulator than the conventional simulator will be suitable for epidural insertion training.