Metastatic prolactinoma presenting as a cervical spinal cord tumour in multiple endocrine neoplasia type one (MEN-1).
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Adult↗
Biomedical subjects
Richard G Bittar
Publications and source records attributed to Richard G Bittar.
Stimulating the human midbrain to reveal the link between pain and blood pressure.
The periaqueductal grey area (PAG) in the midbrain is an important area for both cardiovascular control and modulation of pain. However, the precise relationship between pain and blood pressure is unknown. We prospectively studied 16 patients undergoing deep brain stimulation of the rostral PAG for chronic pain. Pre-operatively, post-operatively, and at 1 year, pain scores were assessed using both visual analogue scores and the McGill Pain Questionnaire. Patients were tested post-operatively to determine whether electrical stimulation of the PAG would modulate blood pressure. We found that the degree of analgesia induced by deep brain stimulation of the rostral PAG in man is related to the magnitude of reduction in arterial blood pressure. We found that this relationship is linear and is related to reduced activity of the sympathetic nervous system. Thus stimulation of the PAG may partly control pain by reducing sympathetic activity as predicted by William James over a century ago.
Adult↗
Neuromodulation for movement disorders.
The field of movement disorder surgery is expanding rapidly. This has been accompanied by improvements in neuromodulation technology and neuroimaging, in addition to a realisation that the medical and destructive neurosurgical methods previously employed do not provide an acceptable long-term benefit for many of these patients. The contemporary treatment of Parkinson's disease, dystonia, and other tremulous disorders using deep brain chronic electrical stimulation will be reviewed, and future directions discussed.
Animals↗
Long-term seizure outcome following surgery for dysembryoplastic neuroepithelial tumor.
OBJECT: Resection of dysembryoplastic neuroepithelial tumor (DNET) is thought to result in favorable seizure outcome, but long-term follow-up data are scarce. The authors present a review of 18 patients who underwent surgical removal of a DNET: 12 via temporal lobectomy and six via lesionectomy. METHODS: The mean long-term follow up was 10.8 years (median 10.4 years, range 7.8 to 14.8 years), and results obtained during this time period were compared with previously reported short-term (mean 2.7 years) seizure outcome data. In the current study, 66.7% patients had an Engel Class I outcome and 55.6% had an Engel Class IA outcome compared with 77.8% and 55.6%, respectively. Temporal lobectomy (Engel Class I, 83.3%; Engel Class IA, 66.7%) led to a better seizure outcome than lesionectomy (Engel Classes I and IA, 33.3%). Two patients (11.1%) required repeated operation and both had an incomplete lesionectomy initially. CONCLUSIONS: Results indicated that complete resection of a DNET leads to a favorable seizure outcome, with epilepsy cure in those who had experienced early postoperative seizure relief. Long-term seizure outcome after surgery is predictable based on the result of short-term follow up.
Adolescent↗
Deep brain stimulation for generalised dystonia and spasmodic torticollis.
Dystonia appears distinct from the other tremulous disorders in that improvement following deep brain stimulation frequently appears in a delayed and progressive manner. The rate of this improvement and the point at which no further progress can be expected are presently unknown. The establishment of these parameters is important in the provision of accurate and relevant prognostic information to these patients, their carers, and their treating physicians. We studied 12 consecutive patients with generalised dystonia (n=6) and spasmodic torticollis (n=6) who underwent bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) and were followed up for a minimum of 2 years postoperatively. Standard rating scales were used to quantify their neurological improvement. Both groups experienced a statistically significant improvement in their rating scores at both one and two years following surgery. At 2 years follow-up, the spasmodic torticollis group exhibited a 59% improvement in their total Toronto Western Spasmodic Torticoilis Rating Scale (TWSTRS) rating score and the generalised dystonia group attained a 46% improvement in their overall Burke, Fahn and Marsden Dystonia Rating Scale (BFMDRS) evaluation. Ninety-five percent of the final improvement was attained by 6.4 months in the generalised dystonia group and by 6.6 months in those with spasmodic torticollis. There was no significant improvement after one year postoperatively. These findings add further support to GPi DBS as an effective treatment for generalised dystonia and spasmodic torticollis, and furnish important information as to the expected rate of improvement and the point at which no further gains can be reasonably anticipated.
Adolescent↗
Somatotopic organization of the human periventricular gray matter.
The periventricular gray (PVG) matter is an established anatomical target for chronic deep brain stimulation (DBS) in the treatment of certain intractable pain syndromes. Data relating to the representation of pain and other somatosensory modalities within the PVG in humans are negligible. We examined the character and location of somatosensory responses elicited by electrical stimulation along the length of the PVG in a patient who underwent unilateral DBS for intractable nociceptive head pain. Consistent responses were obtained and indicated the presence of a somatotopic representation in this region. The contralateral lower limb was represented cranially, followed by the upper limb and trunk, with the face area located caudally, near the level of the superior colliculi. Bilateral representation was only observed in the forehead and scalp.
Adult↗
Deep brain stimulation for phantom limb pain.
Phantom limb pain is an often severe and debilitating phenomenon that has been reported in up to 85% of amputees. Its pathophysiology is poorly understood. Peripheral and spinal mechanisms are thought to play a role in pain modulation in affected individuals; however central mechanisms are also likely to be of importance. The neuromatrix theory postulates a genetically determined representation of body image, which is modified by sensory input to create a neurosignature. Persistence of the neurosignature may be responsible for painless phantom limb sensations, whereas phantom limb pain may be due to abnormal reorganisation within the neuromatrix. This study assessed the clinical outcome of deep brain stimulation of the periventricular grey matter and somatosensory thalamus for the relief of chronic neuropathic pain associated with phantom limb in three patients. These patients were assessed preoperatively and at 3 month intervals postoperatively. Self-rated visual analogue scale pain scores assessed pain intensity, and the McGill Pain Questionnaire assessed the quality of the pain. Quality of life was assessed using the EUROQOL EQ-5D scale. Periventricular gray stimulation alone was optimal in two patients, whilst a combination of periventricular gray and thalamic stimulation produced the greatest degree of relief in one patient. At follow-up (mean 13.3 months) the intensity of pain was reduced by 62% (range 55-70%). In all three patients, the burning component of the pain was completely alleviated. Opiate intake was reduced in the two patients requiring morphine sulphate pre-operatively. Quality of life measures indicated a statistically significant improvement. This data supports the role for deep brain stimulation in patients with phantom limb pain. The medical literature relating to the epidemiology, pathogenesis, and treatment of this clinical entity is reviewed in detail.
Adult↗
Deep brain stimulation for movement disorders and pain.
Deep brain stimulation (DBS) is an expanding field within neurosurgery. With many neurosurgeons performing relatively small numbers of these procedures, detailed descriptions of the technical aspects and nuances of DBS may be worthwhile. We describe our technique for DBS, based on over 300 procedures. This methodology continues to evolve and is refined according to our own experience, our observations of others, technological innovations, and information derived from the neurosurgical literature. The indications for DBS in our service are outlined, the anatomical targets described, and the anaesthetic and surgical aspects detailed.
Deep Brain Stimulation↗
Thalamotomy versus thalamic stimulation for multiple sclerosis tremor.
Disabling intractable tremor occurs frequently in patients with multiple sclerosis (MS). There is currently no effective medical treatment available, and the results of surgical intervention have been variable. Thalamotomy has been the mainstay of neurosurgical therapy for intractable MS tremor, however the popularisation of deep brain stimulation (DBS) has led to the adoption of chronic thalamic stimulation in an attempt to ameliorate this condition. With the goal of examining the relative efficacy and adverse effects of these two surgical strategies, we studied twenty carefully selected patients with intractable MS tremor. Thalamotomy was performed in 10 patients, with chronic DBS administered to the remaining 10. Both thalamotomy and thalamic stimulation produced improvements in postural and intention tremor. The mean improvement in postural tremor at 16.2 months following surgery was 78%, compared with a 64% improvement after thalamic stimulation (14.6 month follow-up) (P > 0.05). Intention tremor improved by 72% in the group undergoing thalamotomy, a significantly larger gain than the 36% tremor reduction following DBS (P < 0.05). Early postoperative complications were common in both groups. Permanent complications related to surgery occurred in four patients overall. Following thalamotomy, long-term adverse effects were observed in three patients (30%), and comprised hemiparesis and seizures. Only one patient in the thalamic stimulation group experienced a permanent deficit (monoparesis). We conclude that thalamotomy is a more efficacious surgical treatment for intractable MS tremor, however the higher incidence of persistent neurological deficits in patients receiving lesional surgery may support the use of DBS as the preferred surgical strategy.
Adult↗
Deep brain stimulation for pain relief: a meta-analysis.
Deep brain stimulation (DBS) has been used to treat intractable pain for over 50 years. Variations in targets and surgical technique complicate the interpretation of many studies. To better understand its efficacy, we performed a meta-analysis of DBS for pain relief. MEDLINE (1966 to February 2003) and EMBASE (1980 to January 2003) databases were searched using key words deep brain stimulation, sensory thalamus, periventricular gray and pain. Inclusion criteria were based on patient characteristics and protocol clarity. Six studies (between 1977-1997) fitting the criteria were identified. Stimulation sites included the periventricular/periaqueductal grey matter (PVG/PAG), internal capsule (IC), and sensory thalamus (ST). The long-term pain alleviation rate was highest with DBS of the PVG/PAG (79%), or the PVG/PAG plus sensory thalamus/internal capsule (87%). Stimulation of the sensory thalamus alone was less effective (58% long-term success) (p < 0.05). DBS was more effective for nociceptive than deafferentation pain (63% vs 47% long-term success; p < 0.01). Long-term success was attained in over 80% of patients with intractable low back pain (failed back surgery) following successful trial stimulation. Trial stimulation was successful in approximately 50% of those with post-stroke pain, and 58% of patients permanently implanted achieved ongoing pain relief. Higher rates of success were seen with phantom limb pain and neuropathies. We conclude that DBS is frequently effective when used in well-selected patients. Neuroimaging and neuromodulation technology advances complicate the application of these results to modern practice. Ongoing investigations should shed further light on this complex clinical conundrum.
Animals↗
Connectivity of the human periventricular-periaqueductal gray region.
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.
Afferent Pathways↗
Stereotactic and Functional Neurosurgery Resident Award: deep brain stimulation for generalized dystonia and spasmodic torticollis: rate and extent of postoperative improvement.
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Adult↗
Driving guidelines and neurological illness: a review.
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Automobile Driver Examination↗
Cerebral metastases in malignant mesothelioma: case report and literature review.
Malignant mesothelioma is an uncommon tumour with an inevitably poor outcome. Statistics from the US National Cancer Institute reveal a steady rise in its incidence over the past 25 years. It typically arises from the pleura, but can also originate in the peritoneum, pericardium, genital tracts and tunica vaginalis. Previously considered a local disease with low incidence of metastasis, there is increasing evidence suggesting otherwise. Reported cases of cerebral metastasis are rare and the vast majority are postmortem findings. This report documents a patient with symptomatic cerebral metastasis from malignant mesothelioma, who underwent craniotomy and excision of two cerebral lesions. It is one of a handful of case reports in the literature in which histological confirmation has been obtained ante-mortem and where surgical treatment of the intracranial mesothelioma was undertaken.
Aged↗
Resective surgery in infants and young children with intractable epilepsy.
Despite the relatively high incidence of epilepsy during the first few years of life, and its documented adverse impact on development, few studies have documented the long term outcomes following epilepsy surgery in infants and young children. We report a consecutive series of 11 patients under 3 years of age who underwent excisional surgery for intractable seizures. A total of 16 resective procedures were performed, and comprised functional hemispherectomy, temporal lobectomy, and lesionectomy. The mean follow-up period was 3 years. At follow-up, 73% (8/11) were seizure-free, with over half of these patients able to cease anti-epileptic medications. Acceleration of neurodevelopment was seen in all patients in whom preoperative developmental delay was present. Quality of life was enhanced in all patients. This series confirms that excellent results can be obtained following excisional surgery in well-selected infants and young children with intractable seizures.
Child Development↗