Impact of Long-term Abnormal Head Position on Carotid Artery Flow in Congenital Fourth Nerve Palsy

To investigate the impact of long-term abnormal head position on internal carotid artery (ICA) and external carotid artery (ECA) flow patterns in patients with unilateral congenital fourth nerve palsy.

This study was conducted in a tertiary clinic and involved 29 patients with congenital fourth cranial nerve palsy, with a vertical deviation greater than 14 prism diopters. Demographic information, clinical presentations, and ophthalmological findings were reviewed, and carotid Doppler ultrasound measurements were compared.

The mean age of the patients was 21.4 ± 10.9 years, with 16 females and 13 males included in the study. The vertical deviation of the cases ranged from 14 to 35 prism diopters (PD), with a median deviation of 22 PD. ECA and ICA diameters were significantly lower on the non-paralytic side compared to the paralytic side (P = .001 and .008), whereas resistive index values were higher on the non-paralytic side (P = .009 and .011). A strong positive correlation was found between the angle of deviation and age (r = 0.685, P < .001), and a negative correlation was noted between carotid flow velocities and angle of deviation (r = -0.546 to -0.626, P < .001).

In patients with congenital fourth nerve palsy, long-term abnormal head position may alter carotid artery flow, reducing vessel diameter, and increasing resistive index on the non-paralytic side. These changes may contribute to complications, suggesting that timely surgical intervention might help prevent carotid flow alterations, facial asymmetry, and musculoskeletal issues.