Asymmetric optic nerve sheath diameter as an outcome factor following cranioplasty in patients harboring the 'syndrome of the trephined'.

UNLABELLED: Decompressive craniectomy (DC) is gaining an increasing role in the neurosurgical treatment of intractable intracranial hypertension, but not without complications. A rare complication is the "syndrome of the trephined" (ST). It occurs when the forces of gravity overwhelm intracranial pressures, leading the brain to become sunken. OBJECTIVE: To determine the usefulness of asymmetric optic nerve sheath diameter (ONSD) as an outcome factor after cranioplasty. METHOD: We followed-up 5 patients submitted to DC and diagnosed with ST. All were submitted to brain MRI to calculate the ONSD. RESULTS: Only two patients presented an asymmetric ONSD, being ONSD larger at the site of craniectomy. Surprisingly these patients had a marked neurological improvement after cranioplasty. They became independent a week after and statistically earlier than others. CONCLUSION: It is presumed that the presence of an asymmetric ONSD in trephined patients is an independent factor of good outcome after cranioplasty.