BACKGROUND: Previous studies have shown that if performed without radiographic guidance, the loss of resistance (LOR) technique can result in inaccurate needle placement in up to 30% of lumbar epidural blocks. To date, no study has shown the efficacy of measuring the depth of the posterior complex (ligamentum flavum, epidural space, and posterior dura) ultrasonographically to distinguish true and false LOR. METHODS: 40 cervical epidural blocks were performed using the LOR technique and confirmed by epidurograms. Transverse ultrasound images of the C6/7 area were taken before each cervical epidural block, and the distances from the skin to the posterior complex, transverse process, and supraspinous ligament were measured on each ultrasound view. The number of LOR attempts was counted, and the depth of each LOR was measured with a standard ruler. Correlation of false and true positive LOR depth with ultrasonographically measured depth was also statistically analyzed. RESULTS: 76.5% of all cases (26 out of 34) showed false positive LOR. Concordance correlation coefficients between the measured distances on ultrasound (skin to ligamentum flavum) and actual needle depth were 0.8285 on true LOR. Depth of the true positive LOR correlated with height and weight, with a mean of 5.64 ± 1.06 cm, while the mean depth of the false positive LOR was 4.08 ± 1.00 cm. CONCLUSIONS: Ultrasonographic measurement of the ligamentum flavum depth (or posterior complex) preceding cervical epidural block is beneficial in excluding false LOR and increasing success rates of cervical epidural blocks.
BACKGROUND: Previous studies have shown that if performed without radiographic guidance, the loss of resistance (LOR) technique can result in inaccurate needle placement in up to 30% of lumbar epidural blocks. To date, no study has shown the efficacy of measuring the depth of the posterior complex (ligamentum flavum, epidural space, and posterior dura) ultrasonographically to distinguish true and false LOR. METHODS: 40 cervical epidural blocks were performed using the LOR technique and confirmed by epidurograms. Transverse ultrasound images of the C6/7 area were taken before each cervical epidural block, and the distances from the skin to the posterior complex, transverse process, and supraspinous ligament were measured on each ultrasound view. The number of LOR attempts was counted, and the depth of each LOR was measured with a standard ruler. Correlation of false and true positive LOR depth with ultrasonographically measured depth was also statistically analyzed. RESULTS: 76.5% of all cases (26 out of 34) showed false positive LOR. Concordance correlation coefficients between the measured distances on ultrasound (skin to ligamentum flavum) and actual needle depth were 0.8285 on true LOR. Depth of the true positive LOR correlated with height and weight, with a mean of 5.64 ± 1.06 cm, while the mean depth of the false positive LOR was 4.08 ± 1.00 cm. CONCLUSIONS: Ultrasonographic measurement of the ligamentum flavum depth (or posterior complex) preceding cervical epidural block is beneficial in excluding false LOR and increasing success rates of cervical epidural blocks.
Authors: Milan P Stojanovic; To-Nhu Vu; Onassis Caneris; Jan Slezak; Steven P Cohen; Christine N Sang Journal: Spine (Phila Pa 1976) Date: 2002-03-01 Impact factor: 3.468
Authors: M Bonazzi; L Bianchi De Grazia; S Di Gennaro; C Lensi; S Migliavacca; M Marsicano; A Riva; D Laveneziana Journal: Minerva Anestesiol Date: 1995-05 Impact factor: 3.051
Authors: Se Hee Kim; Dong Yeon Kim; Jong In Han; Hee Jung Baik; Hahck Soo Park; Guie Yong Lee; Jong Hak Kim Journal: Korean J Anesthesiol Date: 2014-09-24