Predictors of laterality of motor block during epidural analgesia in a mixed surgical population.
BACKGROUND
Predictors of laterality of motor block during epidural analgesia are currently unknown, as studies so far have yielded conflicting results. We aimed to evaluate predictors of post-operative asymmetric lower extremity motor blockade in a mixed surgical population.


METHODS
This is a retrospective analysis of 578 consecutive patients with post-operative epidural analgesia for a variety of surgical procedures. A priori determined potential predictors of unilateral motor block were age, gender, body mass index, type of surgical procedure, vertebral level of puncture, catheter insertion depth into the epidural space and concentration of local anaesthetic. Logistic regression analysis was employed for evaluating predictors of laterality.


RESULTS
Unilateral motor block occurred in 29.2% of the patients. Univariate logistic regression analysis showed that young age, female gender, gynaecologic procedures, a low puncture level, an increased depth of catheter insertion and a high ropivacaine concentration (2 mg/ml vs. less than 2 mg/ml) were significantly associated with increased incidence of laterality. Multivariate analysis revealed that age (OR = 0.73 per decade increase, P = 0.00001), the vertebral level of epidural puncture (OR = 1.37 per lowering vertebral level, P < 0.000001) and the depth of catheter insertion (OR = 1.46 per centimetre deeper, P = 0.001) were independent predictors of unilateral motor block.


CONCLUSIONS
These results suggest that young patients with lumbar epidural analgesia or deep catheter insertion should be frequently monitored for the occurrence of laterality of motor block. Also, these results provide support for a prospective study to determine the optimal catheter insertion depth to decrease the risk of unilateral motor block.
Department of Anaesthesiology, University Hospital of Heraklion, Heraklion, Crete, Greece. x.souvatzis@gmx.de
X
X
Souvatzis
E
E
Diamantaki
D
D
Korda
E
E
Dermitzakis
I
I
Zaganas
N E
NE
Tzanakis
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015360:Analgesia, Epidural / Q000009:adverse effects* / Q000706:statistics & numerical data; D000779:Anesthetics, Local / Q000008:administration & dosage; D015992:Body Mass Index; D002404:Catheterization; D004305:Dose-Response Relationship, Drug; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D016015:Logistic Models; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019148:Neuromuscular Blockade / Q000009:adverse effects* / Q000706:statistics & numerical data; D010149:Postoperative Pain / Q000188:drug therapy; D011237:Predictive Value of Tests; D011677:Punctures; D012189:Retrospective Studies; D012737:Sex Factors; D013514:Surgical Procedures, Operative; D055815:Young Adult
D000779:Anesthetics, Local