///2014 Abstract Details
2014 Abstract Details2019-07-18T14:34:47+00:00

Comparison of Palpatory and Pre-procedural Ultrasound-assisted techniques on performance of spinal anesthesia for Cesarean deliveries - A Randomized Controlled Trial

Abstract Number: S-13
Abstract Type: Original Research

Sudhir Immanni MD1 ; Jose Carvalho MD PhD2; Mrinalini Balki MD3; Kristi Downey MSc4; Xian Y Ye MSc5; Cristian Arzola MD MSc6

Introduction: Pre-procedural ultrasound (US) assessment of the spine is a practical bedside resource used to facilitate the placement of spinal and epidural anesthesia in pregnant women.(1,2) Although certain sonoanatomic features can predict the difficulty of spinal anesthesia in orthopedic patients,(3) this has not been validated in pregnancy. We hypothesize that a pre-procedural US assessment of the spine will improve the ease of spinal anesthesia insertion in term pregnant women undergoing elective cesarean delivery, as compared to the traditional palpatory technique. Furthermore, we hypothesize that sonoanatomic features of the spine can predict the ease of insertion of spinal anesthesia.

Method: 100 patients scheduled for spinal anesthesia were randomized into two groups: US group or Palpatory (Palp) group. Five anesthesia fellows underwent a training program in US assessment of spine and performed all the spinal blocks. The primary outcome was successful spinal block at first needle pass; secondary outcomes were number of needle redirections and attempts, time for successful spinal insertion, bloody tap, paresthesia and pain score. Within 24 h post-procedure, a study investigator, blinded to group allocation, carried out US assessments in all patients for image quality (typical, atypical, inconclusive), and for confirmation of the intervertebral levels for needle punctures.

Results: There were no statistically significant differences between the success at first needle pass (n (%): Palp 18 (38.3), US 20 (37.7); p=0.95), number of needle redirections (mean (SD): Palp 2.8 (4.5), US 2.2 (3.1); p=0.46), > 1 needle attempts (n (%): Palp 10 (21.28), US 7 (13.21); p =0.28) or time for successful spinal insertion (median (IQR), sec: Palp 46.5(25-82), US 36(26-96); p=0.61). Based on image quality, the odds of success were 80% higher in patients with “typical” images compared to those with “atypical” or “inconclusive” image grading.


In Contrast to previous studies(1-3), the use of US did not improve the ease of insertion of spinal anesthesia in term pregnant women when compared to the palpatory technique. The reasons for these results remain to be clarified, however, it appears that the experience of the operators may be an important factor, as we have previously determined that transfer of knowledge for this skill may be quite challenging.4 Interspaces with better image quality were technically less challenging to perform spinal anesthesia as compared to those with poor images.


1. Int J Obstet Anesth 2010;19(4):373-8.

2. J Clin Anesth. 2002 May;14(3):169-75.

3. Reg Anesth Pain Med 2013;38(1):34-8.

4. Can J Anesth 2010; 57: 120-126

SOAP 2014