TY - JOUR
T1 - Cutaneous Sensory Block Area, Muscle-Relaxing Effect, and Block Duration of the Transversus Abdominis Plane Block
T2 - A Randomized, Blinded, and Placebo-Controlled Study in Healthy Volunteers
AU - Støving, Kion
AU - Rothe, Christian
AU - Rosenstock, Charlotte V
AU - Aasvang, Eske K
AU - Lundstrøm, Lars H
AU - Lange, Kai H W
PY - 2015/7/11
Y1 - 2015/7/11
N2 - Background and Objectives The transversus abdominis plane (TAP) block is a widely used nerve block. However, basic block characteristics are poorly described. The purpose of this study was to assess the cutaneous sensory block area, muscle-relaxing effect, and block duration. Methods Sixteen healthy volunteers were randomized to receive an ultrasound-guided unilateral TAP block with 20 mL 7.5 mg/mL ropivacaine and placebo on the contralateral side. Measurements were performed at baseline and 90 minutes after performing the block. Cutaneous sensory block area was mapped and separated into a medial and lateral part by a vertical line through the anterior superior iliac spine. We measured muscle thickness of the 3 lateral abdominal muscle layers with ultrasound in the relaxed state and during maximal voluntary muscle contraction. The volunteers reported the duration of the sensory block and the abdominal muscle-relaxing effect. Results The lateral part of the cutaneous sensory block area was a median of 266 cm2 (interquartile range, 191-310 cm2) and the medial part 76 cm2 (interquartile range, 54-127 cm2). In all the volunteers, lateral wall muscle thickness decreased significantly by 9.2 mm (6.9-15.7 mm) during a maximal contraction. Sensory block and muscle-relaxing effect duration were 570 minutes (512-716 minutes) and 609 minutes (490-724 minutes), respectively. Conclusions Cutaneous sensory block area of the TAP block is predominantly located lateral to a vertical line through the anterior superior iliac spine. The distribution is nondermatomal and does not cross the midline. The muscle-relaxing effect is significant and consistent. The block duration is approximately 10 hours with large variation.
AB - Background and Objectives The transversus abdominis plane (TAP) block is a widely used nerve block. However, basic block characteristics are poorly described. The purpose of this study was to assess the cutaneous sensory block area, muscle-relaxing effect, and block duration. Methods Sixteen healthy volunteers were randomized to receive an ultrasound-guided unilateral TAP block with 20 mL 7.5 mg/mL ropivacaine and placebo on the contralateral side. Measurements were performed at baseline and 90 minutes after performing the block. Cutaneous sensory block area was mapped and separated into a medial and lateral part by a vertical line through the anterior superior iliac spine. We measured muscle thickness of the 3 lateral abdominal muscle layers with ultrasound in the relaxed state and during maximal voluntary muscle contraction. The volunteers reported the duration of the sensory block and the abdominal muscle-relaxing effect. Results The lateral part of the cutaneous sensory block area was a median of 266 cm2 (interquartile range, 191-310 cm2) and the medial part 76 cm2 (interquartile range, 54-127 cm2). In all the volunteers, lateral wall muscle thickness decreased significantly by 9.2 mm (6.9-15.7 mm) during a maximal contraction. Sensory block and muscle-relaxing effect duration were 570 minutes (512-716 minutes) and 609 minutes (490-724 minutes), respectively. Conclusions Cutaneous sensory block area of the TAP block is predominantly located lateral to a vertical line through the anterior superior iliac spine. The distribution is nondermatomal and does not cross the midline. The muscle-relaxing effect is significant and consistent. The block duration is approximately 10 hours with large variation.
U2 - 10.1097/AAP.0000000000000252
DO - 10.1097/AAP.0000000000000252
M3 - Journal article
C2 - 25923818
SN - 1098-7339
VL - 40
SP - 355
EP - 362
JO - Regional Anesthesia and Pain Medicine
JF - Regional Anesthesia and Pain Medicine
IS - 4
ER -