Impact of Neck Extension During Thyroidectomy on Postoperative Cognitive Function

In a randomized controlled trial on neck extension during thyroidectomy, researchers found a statistically significant reduction in early postoperative Montreal Cognitive Assessment (MoCA) scores at about 6 hours (20.56 ± 2.71 vs 23.57 ± 2.37; P < 0.001).

The trial randomized patients after tracheal intubation to shoulder-roll-assisted neck extension versus no roll and measured MoCA at a prespecified ~6-hour postoperative timepoint. MoCA was used consistently as the primary cognitive measure, supporting internal comparability. The cohort was limited to elective thyroidectomy patients, which narrows generalizability beyond similar head-and-neck procedures and anesthetic contexts.

Optic nerve sheath diameter (ONSD) increased over time in both groups, but repeated-measures analysis showed no significant between-group difference (P = 0.333), meaning ONSD did not parallel the MoCA decrement by allocation. Because ONSD is a bedside surrogate for intracranial pressure (ICP), its neutrality argues against a large, acute ICP-mediated mechanism linking neck extension to the early cognitive change. The greater cervical angulation measured with the shoulder roll therefore suggests a positional effect without a clear, gross ICP signal — reassuring for major ICP shifts but not excluding subtler cerebrovascular or perfusion changes.

The evidence is strong for an early, procedure-specific cognitive signal (validation confidence 0.95) but limited by a single procedure cohort and a single early timepoint; longer-term outcomes remain unknown.