Background and Aims Spinal analgesia is the technique for pain control of pregnant patients. There is a dural sac thickness space called “subdural spaced”. One of the causes of a failed epidural block is to inject local anesthetic into the subdural space, the clinic is a too high slow lock with a patched distribution, dyspnea and hypotension.

Other forms of subdural block are described in the literature , like for example Horner’s Syndrome wich is due to the block with local anesthetics of sympathetic fibers (C8-T1).

Methods 39 year old pregnant woman with no medical history of interest

Lumbar epidural catheter was inserted as analgesic treatment:

- Negative dose test

- Negative aspiration test for blood and cerebrospinal fluid

- Levobupivacaine 0,125%+200 mgr of fentanyl 12 mL/h

Analgesia was not effective

New boluses of local anesthetic were injected with a new lumbar catheter.

After 180 minutes and prolonged labor, begins with blurred vision, miosis, ptosis and right enophthalmos wich is called unilateral Horner’s syndrome

Results The differential diagnosis of high spinal block with patchy distribution, asymmetric and minimal motor block compatible with subdural block is proposed.

Clinical symptoms compatible with cephalic distribution of local anesthetic until reaching the stellate ganglion of C8-T1 debuting as unilateral Horner’s syndrome.

Conclusions Most cases of Horner’s Syndrome described in neuroaxial anesthesia are related to pregnant patients. The increased intra-abdominal pressure of pregnancy accompanied by prolonged labor during delivery and the increased sensitivity of the same seem to be predisposing factors. In most cases, they resolve spontaneously.