Deep Brain Stimulation of the Pedunculopontine Nucleus in a Patient with Freezing of Gait

Abstract

Case Presentation: A 54-year-old male patient presenting probable multiple system atrophy with predominant parkinsonism who underwent bilateral deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) is presented. The patient had dominant freezing of gait (FOG), levodopa-resistant bradykinesia, and autonomic disturbances, but with a good cognitive condition. Methods: The patient underwent bilateral DBS of the PPN, which ended with modest benefits. Results and Conclusion: Although he had a short postoperative follow-up (6 months), his neurological status remained stable and PPN DBS provided modest improvements in the gait disorder and freezing episodes. This unusual case suggests that the mesencephalic pedunculopontine region may have a role in locomotor symptoms and the potential to provide a limited improvement in FOG.

A Commentary on the Lead Positioning for Deep Brain Stimulation in the Pedunculopontine Tegmental Nucleus in a Patient Affected by Multiple System Atrophy

“…The case report by Acar et al [1] recently published in Stereotactic and Functional Neurosurgery, as do other similar case reports [2,3] populating the literature concerning deep brain stimulation (DBS) of the pedunculopontine tegmental nucleus (PPTg), demonstrates the growing interest of neurosurgeons in the use of new neurosurgical targets for the treatment of movement disorders in drug-resistant patients. Such an interest is especially prompted by the need to treat symptoms for which traditional stimulation of the subthalamic nucleus has given unsatisfactory results [4][5][6] , such as gait freezing and postural instability.…”

“…We wish to point out that the axial slices of postoperative MRIs presented by Acar et al [1] ( fig. 1 , 2 ) show a position of the stimulating tip that clearly differs from the region ( fig.…”

“…However, skepticism remains when observations are sporadic and carried out on a single case or on a few patients, who are often not affected by Parkinson's disease (PD) but rather by parkinsonian syndromes such as progressive supranuclear palsy and multiple system atrophy. The patient implanted in the PPTg by Acar et al [1] suffered from multiple system atrophy. In this pathology, neither medical therapy nor neurosurgery of traditional targets improves motor signs; thus, the hope was that PPTg DBS would have a positive outcome, which did not occur.…”

“…3 ) that we targeted in the 27 patients so far implanted in our experience. [1] . The leads appear to be medial to the caudal part of the PPTg.…”

“…2. Reconstruction of Paxinos and Huang's atlas (slice +33 mm from the Obex) of the lead positions in the patient implanted by Acar et al [1] . The MRI axial slice is the same as that reported in figure 1.…”