Surgical anatomy of the pedunculopontine and peripeduncular nuclei

The pedunculopontine nucleus is a promising new target for deep brain stimulation (DBS) in Parkinsonian patients with gait disturbance and postural instability refractory to other treatment modalities. This region of the brain is unfamiliar territory to most functional neurosurgeons and has been the subject of inaccurate descriptions and representations. This contribution reviews the anatomy of the human pedunculopontine nucleus as well as that of another brainstem nucleus that carries a vaguely similarly sounding name and with which the former has been confused—the peripeduncular nucleus. The stereotactic coordinates for both structures are reviewed, as are methods of anatomical localization in surgical practice. The precise understanding and use of anatomical terminology together with accurate postoperative lead localization are essential when reporting on the clinical effects of novel DBS targets.