Randomized comparison of popliteal-sciatic perineural catheter tip migration and dislocation in a cadaver model using two catheter designs.
BACKGROUND
New catheter-over-needle (CON) technology for continuous peripheral nerve blockade has emerged, but its effect on the risk of perineural catheter tip dislocation is unknown. Less flexible catheters may be more likely to migrate away from the nerve with simulated patient movement. In the present study, we evaluated catheter tip migration between CON catheters and traditional catheter-through-needle (CTN) catheters during ultrasound-guided short-axis in-plane (SAX-IP) insertion.


METHODS
We evaluated the migration of popliteal-sciatic catheters in a prone, unembalmed male cadaver. Thirty catheter placement trials were divided randomly into two groups based on the catheter type: CON or CTN. A single anesthesiology resident placed the catheters by SAX-IP insertion, and the catheters were then examined by ultrasound before and after ipsilateral knee range of motion (ROM) exercises (0°-130° flexion). A blinded expert regional anesthesiologist performed caliper measurements on the ultrasound images before and after the ROM exercises. The primary outcome was the change in distance from the catheter tip to the center of the nerve (cm) between before and after the ROM exercises.


RESULTS
The change in the tip-to-nerve distance (median [10th-90th percentile]) was 0.06 (-0.16 to 0.23) cm for the CTN catheter and 0.00 (-0.12 to 0.69) for the CON catheter (P = 0.663). However, there was a statistically significant increase in dislocation out of the nerve compartment for the CON catheter (4/15; 0/15 for CTN) (P = 0.043).


CONCLUSIONS
Although the use of different catheter designs had no effect on the change in the measured migration distance of popliteal-sciatic catheters, 27% of the CON catheters were dislocated out of the nerve compartment. These results may influence the choice of catheter design when using SAX-IP perineural catheter insertion.
Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, USA.
Lauren
L
Steffel
Anesthesiology and Perioperative Care Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
Steven K
SK
Howard
Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, USA.
Lindsay
L
Borg
Anesthesiology and Perioperative Care Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
Edward R
0000-0003-2735-248X
ER
Mariano
Anesthesiology and Perioperative Care Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
Jody C
JC
Leng
Anesthesiology and Perioperative Care Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA.
T Edward
TE
Kim
Conduction anesthesia; Dislocations; Nerve block; Perineural catheter; Sciatic nerve; Ultrasonography