Sonographic evaluation of lumbar interlaminar space opening in a variety of patient body positions for optimal neuraxial anesthesia delivery.
OBJECTIVE
To find the position that provided the most comfort, as well as the widest L3-L4 interlaminar space opening.


METHODS
Pilot study.


METHODS
Operating room.


METHODS
Thirty-two healthy volunteers.


METHODS
L3-L4 interlaminar space was measured on volunteers assuming a baseline position (sitting upright) and 5 study positions: (1) sitting in fetal position, (2) sitting on a table tilted at 30°, (3) sitting while hugging an exercise ball, (4) sitting with midcalves on the table's edge, and (5) lying on one side in fetal position. Interlaminar spaces were measured to determine which position resulted in the largest interlaminar space compared with baseline. The comfort level of each position was rated by subjects using a visual analogue scale from 1 to 10.


RESULTS
The means of the interlaminar openings in all study positions were significantly different from baseline, with the "sitting fetal" having the greatest difference, (1.32mm, P<.001), followed by "hugging a ball" (0.94mm, P<.001) and "lying fetal" (0.92mm, P<.001). Alternatively, when using "sitting fetal" (a more commonly used position) as a comparative baseline, "hugging a ball" and "lying fetal" showed smaller but not significantly different interlaminar openings (Δ=-0.38mm, P value = .221 and Δ=-0.40mm, P value = .164, respectively)."Sitting on a tilted table" and "sitting midcalf" showed significantly smaller interlaminar openings (Δ=-0.52mm, P value = .025 and Δ=-0.72mm, P value < .001, respectively) when compared with the alternative baseline of "sitting fetal." Mean visual analogue scale scores for comfort showed that "hugging a ball" (7.8/10), "lying fetal" (7.5/10), and "sitting fetal" (7.2/10) positions had the highest ratings.


CONCLUSIONS
Ultrasonographic measurements carried out on 32 subjects showed that "sitting fetal," "lying fetal," and "hugging a ball" positions provided the widest L3-L4 interlaminar openings. These 3 positions were also found to be more comfortable.
SUNY Downstate Medical Center, Department of Anesthesiology, MSC #6 450 Clarkson Ave, Brooklyn, NY 11203, USA. Electronic address: ddimaculanganmd@gmail.com.
Dennis P
DP
Dimaculangan
SUNY Downstate Medical Center, Department of Anesthesiology, MSC #6 450 Clarkson Ave, Brooklyn, NY 11203, USA. Electronic address: jonmazer@gmail.com.
Jonathan A
JA
Mazer
SUNY Downstate Medical Center, Department of Anesthesiology, MSC #6 450 Clarkson Ave, Brooklyn, NY 11203, USA. Electronic address: lmaracaja@gmail.com.
Luiz F
LF
Maracaja-Neto
D000328:Adult; D000767:Anesthesia, Epidural; D000775:Anesthesia, Spinal; D000779:Anesthetics, Local / Q000008:administration & dosage*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007278:Injections, Spinal / Q000379:methods*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008161:Lumbosacral Region / Q000000981:diagnostic imaging; D008297:Male; D056888:Patient Positioning; D010865:Pilot Projects; D014463:Ultrasonography
D000779:Anesthetics, Local