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Kristian J. Bulluss, Erlick A. Pereira, Carole Joint and Tipu Z. Aziz

Recent publications have demonstrated that deep brain stimulation for Parkinson's disease still exerts beneficial effects on tremor, rigidity, and bradykinesia for up to 10 years after implantation of the stimulator. However with the progression of Parkinson's disease, features such as cognitive decline or “freezing” become prominent, and the presence of an implanted and functioning deep brain stimulator can impose a profound burden of care on the clinical team and family. The authors describe their experience in treating 4 patients who underwent removal of the implanted device due to either progressive dementia requiring full-time nursing or due to infection, and who subsequently underwent a unilateral pallidotomy.

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Ashwin Viswanathan, Viraat Harsh, Erlick A. C. Pereira and Tipu Z. Aziz

Object

Cingulotomy has been reported in the literature as a potential treatment option for refractory cancer-related pain. However, the optimal candidates for this intervention and the outcomes are not well characterized. The goal of this study was to review the available literature on cingulotomy, specifically for cancer-related pain.

Methods

A search of PubMed, PubMed Central, the Cochrane Library, and MEDLINE was performed to identify all articles discussing cingulotomy for cancer pain. The text strings “cingul*” and “pain” were separated by the Boolean AND operator, and used to perform the query on PubMed. Only studies in which a stereotactic technique was used, as opposed to an open technique, and specifically detailing outcomes for cancer pain were included. For centers with multiple publications, care was taken not to double-count individual patients.

Results

The literature review revealed only 8 unique studies describing outcomes of stereotactic cingulotomy for cancer pain. Between 32% and 83% of patients had meaningful pain relief. The location of the lesion was variable, ranging between 1 cm and 4 cm posterior to the tip of the anterior horn. Although serious adverse events are rare, a decline in focused attention can been seen in the early postoperative period, along with apathy and decreased activity.

Conclusions

For patients with cancer pain with diffuse pain syndromes, head and neck malignancies, and significant emotional distress, cingulotomy may be a safe treatment option with minimal cognitive changes.

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Robert J. Coffey

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Helen Smith, Carlolf Joint, David Schlugman, Dipankar Nandi, John F. Stein and Tipu Z. Aziz

Motor cortex stimulation is increasingly reported in the literature as a surgical option for the alleviation of neuropathic pain. The authors review the published literature and present their results including those demonstrated in a randomized controlled trial that confirmed the efficacy of the procedure. Patient selection and prediction of outcomes, however, remain difficult issues.

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Dipankar Nandi, Simon Parkin, Richard Scott, Jonathan L. Winter, Carole Joint, Ralph Gregory, John Stein and Tipu Z. Aziz

✓ The authors report the neurological, neurophysiological, and neuropsychological effects of using long-term bilateral pallidal high-frequency deep brain stimulation (DBS) in a case of disabling camptocormia. Deep brain stimulation electrodes were implanted stereotactically to target the globus pallidus internus (GPi) bilaterally. Local field potentials (FPs) were recorded using the DBS electrodes and concurrent abdominal flexor electromyography (EMG) potentials during camptocormic episodes. Videotaped assessments of the movement disorder and neuropsychological evaluations of the patient before implantation and 6 months after initiation of pallidal stimulation were recorded.

There was significant functional improvement following long-term pallidal stimulation, and some improvement was noted in neuropsychological scores. A temporal correlation between the GPi FPs and EMG-recorded rectus abdominis potentials was evident. There were no treatment-related adverse effects. The authors have found that long-term pallidal stimulation was safe and offered functional benefit to a patient with this severely disabling condition. The physiological studies may help further the understanding of the pathophysiology of this rare entity.

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Dipankar Nandi, Simon Parkin, Richard Scott, Jonathan L. Winter, Carole Joint, Ralph Gregory, John Stein and Tipu Z. Aziz

The authors report the neurological, neurophysiological, and neuropsychological effects of using chronic bilateral pallidal high-frequency deep brain stimulation (DBS) in a case of disabling camptocormia.

Deep brain stimulation electrodes were implanted stereotactically to target the globus pallidus internus (GPi) bilaterally. Local field potentials (FPs) were recorded using the DBS electrodes and concurrent abdominal flexor elec-tromyography (EMG) potentials during camptocormic episodes. Videotaped assessments of the movement disorder and neuropsychological evaluation before implantation and at 6 months after initiation of pallidal stimulation were recorded.

There was significant functional improvement following chronic pallidal stimulation, and some improvement was noted in neuropsychological scores. The GPi FPs showed temporal correlation with EMG-recorded rectus abdominis potentials. There were no treatment-related adverse effects.

The authors have found that chronic pallidal stimulation was safe and offered functional benefit in this severely disabling condition. The physiological studies may help further the understanding of the pathophysiology of this rare entity.

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Emma Sillery, Richard G. Bittar, Matthew D. Robson, Timothy E. J. Behrens, John Stein, Tipu Z. Aziz and Heidi Johansen-Berg

Object. The periventricular gray (PVG) zone and its continuation, the periaqueductal gray (PAG) substance, have been targets for deep brain stimulation (DBS) in the alleviation of intractable pain for longer than two decades. Nevertheless, the anatomical connectivity of this region has been fairly poorly defined. The effects of DBS in this region are probably related to the release of endogenous endorphins, but until the connectivity of this region is better understood the mechanisms will remain unclear.

Methods. Diffusion tractography was used to trace the pathways of the PVG—PAG region in seven healthy human volunteers. Images were acquired with the aid of a 1.5-tesla magnetic resonance imaging system. The region of interest was located just lateral to the posterior commissure and extended caudally to the level of the superior colliculus. Probabilistic diffusion tractography was performed from each voxel in each patient's PVG—PAG region.

The PVG—PAG region was found to yield descending projections to the spinal cord and cerebellum. Ascending projections to the thalamus and frontal lobes were also observed.

Conclusions. These findings suggest that the PVG—PAG region may modulate pain by two mechanisms: one involving the antinociceptive system in the spinal cord and the other involving influences on the central pain network.

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Jennifer A. McNab, Natalie L. Voets, Ned Jenkinson, Waney Squier, Karla L. Miller, Guy M. Goodwin and Tipu Z. Aziz

In this study, the authors performed deep brain stimulation (DBS) of the subgenual anterior cingulate cortex (SACC) in a patient with a history of bipolar disorder. After a right thalamic stroke, intractable depression without mood elevation or a mixed state developed in this patient. He underwent bilateral SACC DBS and died 16 months afterwards. Anatomical connections were studied in this patient preoperatively and postmortem using diffusion tractography (DT). A comparison of in vivo and high resolution ex vivo connectivity patterns was performed as a measure of the utility of in vivo DT in presurgical planning for DBS. Diagnostic measures included neuropsychological testing, preoperative and ex vivo DT, and macroscopic neuropathological assessment. Post-DBS depression rating scores did not improve. In vivo and ex vivo DT revealed markedly reduced limbic projections from the thalamus and SACC to the amygdala in the right (stroke-affected) hemisphere. A highly selective right mediothalamic lesion was associated with the onset of refractory depression. Reduced amygdalar-thalamic and amygdalar-SACC connections could be a contraindication to DBS for depression. Correspondence between preoperative and higher resolution ex vivo DT supports the validity of DT as a presurgical planning tool for DBS.