Cranial versus caudal thoracic epidural anesthesia using three volumes of lidocaine in conscious Beagle dogs.

OBJECTIVE: To compare the effects of epidural injection of three volumes of lidocaine injected at the third (T3) or eleventh thoracic vertebra (T11) in conscious dogs to induce thoracic epidural anesthesia (TEA) and to measure the epidural dispersion of iohexol under similar conditions. STUDY DESIGN: Prospective crossover experiment. ANIMALS: A group of five Beagle dogs weighing 10.4 ± 0.5 kg (mean ± standard deviation). METHODS: Each dog was anesthetized twice, separated by 1 week, for inserting an epidural catheter at the lumbosacral space and advancing the tip to T3 (treatment TEAT3) or T11 (treatment TEAT11). For each treatment, three volumes of 2% lidocaine (0.05, 0.10 and 0.20 mL kg-1) were administered at 24 hour intervals, and sensory blockade (SB) of dermatomes was estimated by pinching the skin with mosquito forceps. Under identical conditions of injection volume and site, iohexol was administered 3 hours after lidocaine injection to identify epidural distribution (ED) using computed tomography. The effects of injection site and volume on SB of thoracic dermatomes and ED were analyzed using a linear mixed model (p < 0.05). RESULTS: Thoracic SB and ED significantly increased as the volume increased (p < 0.001 and p < 0.001, respectively), and significantly decreased in TEAT3 than in TEAT11 (p = 0.011 and p = 0.002, respectively). Cervical SB was obtained in three of five dogs in TEAT3 and two of five dogs in TEAT11 injected with 0.20 mL kg-1. One dog showed temporary inspiratory stridor probably caused by bilateral laryngeal paralysis, but no hypoxia. CONCLUSIONS AND CLINICAL RELEVANCE: TEA induced at T3 produced less thoracic SB than did TEA at T11 with the same volumes of lidocaine. The cervical SB obtained with the highest volume of lidocaine may increase the risk of laryngeal paralysis and pulmonary aspiration.

The effect of lumbar facet joint injection levels on spinopelvic parameters and functional outcome.

BACKGROUND: Low back pain is a very common musculoskeletal complaint that impacts patients' quality of life in numerous ways. Facet joint injection is a widely used spinal intervention to relieve back pain. Effects of facet joint injection on spinopelvic parameters and the relationship between injection levels and spinopelvic parameter changes have not been evaluated before. OBJECTIVE: To compare spinopelvic parameters before and after injections at different levels, and to evaluate the correlation between these changes and functional outcome. METHODS: 144 patients were included in the study and retrospectively grouped by injection level: Group 1 (n= 72), L4-L5 and L5-S1, and group 2 (n= 72), L1-L2, L2-L3, L3-L4, L4-L5 and L5-S1. Pre- and post-injection Oswestry Disability Index (ODI), sacral slope, pelvic tilt, pelvic incidence, and intervertebral angles between T12 and S1 were compared. The correlation between ODI and radiographic parameter changes was evaluated. RESULTS: The pre- to post-injection ODI change was significantly lower in group 2 (p= 0.010). There was no significant difference between the groups in terms of pre- and post-injection spinopelvic parameters before and after injection (p> 0.05) except pelvic tilt (p= 0.001 and p= 0.007, respectively). There was a significant moderate positive correlation between the change in the ODI value and the change in pelvic tilt (P= 0.012, r= 0.581). CONCLUSIONS: Multilevel lumbar facet injections are clinically more effective than only two-level lower level lumbar injections. Pelvic tilt changes positively correlate with the ODI score changes.