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Constantine Constantoyannis

Publications and source records attributed to Constantine Constantoyannis.

10 recordsLinked to original sources
PubMed2006

Expectation and the placebo effect in Parkinson's disease patients with subthalamic nucleus deep brain stimulation.

To determine whether the degree to which a patient with Parkinson's disease expects therapeutic benefit from subthalamic nucleus-deep brain stimulation (STN-DBS) influences the magnitude of his or her improved motor response, 10 patients with idiopathic Parkinson's and bilateral STN-DBS were tested after a 12-hour period off medication and stimulation. Four consecutive UPDRS III scores were performed in the following conditions: (a) stimulation OFF, patient aware; (b) stimulation OFF, patient blind; (c) stimulation ON, patient aware; and (d) stimulation ON, patient blind. Statistical significance (P = 0.0001) was observed when comparing main effect ON versus OFF (mean ON: 32.55; mean OFF: 49.15). When the stimulation was OFF, patients aware of this condition had higher UPDRS motor scores than when they were blinded (mean: 50.7 vs. 47.6). With the stimulation ON, UPDRS motor scores were lower when the patients were aware of the stimulation compared with when they were blinded (mean: 30.6 vs. 34.5). The interaction between these levels was significant (P = 0.049). This variation was important for bradykinesia and was not significant for tremor and rigidity. The authors conclude that the information about the condition of the stimulation enhanced the final clinical effect in opposite directions. The results presented support the role of expectation and placebo effects in STN-DBS in Parkinson's disease patients.

Adult↗
PubMed2005

Reducing hardware-related complications of deep brain stimulation.

BACKGROUND: Deep brain stimulation (DBS) is used increasingly worldwide for the treatment of Parkinson's disease, dystonia, tremor and pain. As with any implanted system, however, DBS introduces a new series of problems related to its hardware. Infection, malfunction and lead migration or fracture may increase patient morbidity and should be considered when evaluating the risk/benefit ratio of this therapy. This work highlights several factors felt to increase DBS hardware complications. METHODS: The authors undertook a prospective analysis of their patients receiving this therapy in two Canadian centres, over a four-year period. RESULTS: One hundred and forty-four patients received 204 permanent electrode implants. The average follow-up duration was 24 months. Complications related to the DBS hardware were seen in 11 patients (7.6%). There were two lead fractures (1.4%) and nine infections (6.2%) including two erosions (1.4%). There was a significantly greater risk of infection in patients who underwent staged procedures with externalization. In patients with straight scalp incisions, the rate of infection was higher than that seen with curved incisions. CONCLUSION: Hardware complications were not common. A period of externalization of the electrodes for a stimulation trial was associated with an increased infection rate. It is also possible that a straight scalp incision instead of curvilinear incision may lead to an increase in the rate of infection. With a clear understanding of the accepted DBS device indications and their potential complications, patients may make a truly informed decision about DBS technology.

Adolescent↗
PubMed2004

Atlantoaxial instability and myelopathy due to an ossiculum terminale persistens.

BACKGROUND: Many cases of ossiculum terminale in Down's syndrome have been reported. We describe an unusual case of sudden atlantoaxial instability in a previously healthy woman without a history of trauma due to a dystopic ossiculum of the dens that could be classified as an ossiculum terminale persistens or as os odontoideum according to different classification proposals. CASE REPORT: A 36-year-old woman was admitted with neck pain and Lhermitte's sign. Neurological examination revealed spasticity of both upper and lower limbs. Radiological evaluation of the cervical spine showed an ossiculum close to the anterior arch of the atlas. Flexion and extension films revealed an atlantoaxial instability. Additional findings using computerized tomography and magnetic resonance Imaging provided significant information about the soft tissue structures. The patient underwent a C1-C2 posterior cervical wiring and interspinous fusion with the Sonntag technique. Postoperatively, the patient was neurologically intact and without any symptoms. CONCLUSIONS: In the present report we address the notion that, in cases of atlantoaxial instability and myelopathy due to a dens anomaly, surgical intervention is required and that there is no need to distinguish which type of anomaly really exists according to different classification schemes.

Adult↗
PubMed2004

Tremor induced by thalamic deep brain stimulation in patients with complex regional facial pain.

We report on two patients who developed a new postural and action tremor after chronic stimulation of the contralateral thalamus (VPM nucleus) during treatment of a complex regional facial pain syndrome. The tremor was only present during deep brain stimulation (DBS) and was suppressed with adjustment of the stimulation parameters. Tremor was seen only with low frequency stimulation (50 Hz or lower) and disappeared with higher stimulation frequencies. In addition to being an unusual side effect of thalamic DBS, we believe that this phenomenon affords insight into one possible mechanism underlying essential tremor (ET). A central oscillatory mechanism involving the olivocerebellar complex and the thalamus, which is a part of the cerebro-cerebello-cerebral circuit, is thought to play an important role in the genesis of ET. Induction of a tremor resembling ET in our patients indicates an active role for low frequency stimulation. A plausible explanation for this is that low frequency stimulation in the thalamic area enhances the output of the tremor-producing network. This leads credence to the concept of central oscillations in a "tremor circuit," of which the thalamus is a part, as being important in ET.

Adult↗
PubMed2004

Electrocardiogram artifacts caused by deep brain stimulation.

BACKGROUND: Deep brain stimulation (DBS) is increasingly used to treat a variety of neurological conditions (e.g. movement disorders and chronic pain). This prospective study was designed to detect electrocardiogram (ECG) artifacts induced by deep brain stimulation and to investigate which factors (patient disease, electrode position within the brain or type of stimulation) produced these artifacts. METHODS: Twelve patients (four women, eight men) with deep brain stimulators were enrolled in the study. Patients were selected to represent the common indications for DBS (Parkinson's disease, tremor, dystonia), the common electrode locations (pallidum, thalamus, subthalamic nucleus) and the two types of stimulation (monopolar, bipolar). Patients had one ECG with the DBS turned 'on' and another with the DBS turned 'off'. The ECGs were then randomized and read by a cardiologist blinded to the status of the patient and DBS and artifacts were noted to be either present or absent. RESULTS: The six patients using monopolar stimulation all had artifacts on their electrocardiograms. These artifacts were severe enough to interfere with ECG interpretation. There were no artifacts detected in the six patients using bipolar stimulation. Electrode location and patient disease appeared to have no effect on ECG artifact. CONCLUSIONS: Deep brain stimulation can cause ECG artifacts when monopolar settings are used. These artifacts are not present with bipolar settings or when the DBS is turned 'off'. Knowledge of these potential ECG artifacts and how to avoid them is essential to facilitate accurate ECG interpretation.

Adult↗
PubMed2003

The treatment of trigeminal neuralgia in patients with multiple sclerosis using percutaneous radiofrequency rhizotomy.

BACKGROUND: Trigeminal neuralgia (TN) has a higher incidence among patients with multiple sclerosis (MS) than in the general population. This cohort of MS patients with TN presents a series of management challenges including poor tolerance of antineuralgic medications and occasional bilateral presentation. We analyzed our surgical series of MS patients presenting with TN who were treated with percutaneous radiofrequency rhizotomy to estimate the success, failure and recurrence rate of this procedure for those patients. METHODS: Surgical reports were retrospectively reviewed between the years 1996-2000. Patients with MS and TN who received a percutaneous rhizotomy during that time were included in the study and followed until the end of 2002. Data regarding age, sex, duration of MS and pain, response to medical treatment, pain distribution and surgical outcome were evaluated. RESULTS: There were thirteen patients with MS and medically refractory TN treated with percutaneous radiofrequency rhizotomy. The average age at diagnosis for MS was 41 with TN beginning an average of eight years later. Following rhizotomy, complete pain relief without the need for any medication was achieved in 81% of the patients. The addition of medications resulted in pain control in the remaining patients. During a mean follow-up period of 52 months, there was a 50% recurrence rate. There were no complications related to the procedure and the associated facial numbness was well-tolerated. CONCLUSIONS: Percutaneous radiofrequency rhizotomy is a safe and effective method for the treatment of TN in patients with MS. The unique susceptibility of this cohort to the side effects of antineuralgic medications may require early consideration of rhizotomy.

Adult↗
PubMed2003

Neuroepithelial cysts presenting with movement disorders: two cases.

BACKGROUND: The authors present two cases of movement disorders caused by neuroepithelial cysts and highlight their management. Neuroepithelial cysts are ependymal or epithelial lined fluid collections of unknown etiology within the central nervous system parenchyma with no obvious ventricular or subarachnoid connection. Most cysts are asymptomatic, however, some present with seizures, mass effect, or rarely with movement disorders. CASE REPORTS: The first patient, a 27-year-old female, presented with progressive weakness, dystonic posturing, tremor, ballismus and choreoathetotic movements of her right upper extremity. Her symptoms improved after stereotactic drainage of a neuroepithelial cyst in her basal ganglia but recurred within a year. The second case, a 56-year-old female, presented with diplopia, nystagmus, gait imbalance and hemiparesis. Her symptoms improved after stereotactic drainage of a midbrain neuroepithelial cyst. The cyst reaccumulated over the next few years and she became symptomatic with left arm tremor and facial weakness. Aspiration was again performed with symptomatic improvement for nine months. Her tremor recurred and a cyst access device was placed stereotactically. She improved and has remained stable for over a year. CONCLUSION: Simple stereotactic drainage of neuroepithelial cysts has a high recurrence rate. The authors recommend considering placement of a drainage device to facilitate aspiration of the cyst fluid during follow-up, if needed.

Adult↗
PubMed2003

Laypersons' expectation of the sequelae of whiplash injury: a cross-cultural comparative study between Canada and Greece.

BACKGROUND: The objective of the present study is to compare the frequency and nature of expected 'whiplash' symptoms in Greece [a country where the chronic whiplash syndrome is rare or unknown] with that in Canada. MATERIAL/METHODS: A symptom checklist was administered to 2 subject groups selected from local companies in Patras Greece, and Edmonton, Canada, respectively. Subjects were asked to imagine having suffered a neck sprain [whiplash injury] with no loss of consciousness in a motor vehicle collision, and to check which, of a variety of symptoms, they would expect might arise from the injury. For symptoms they anticipated, they were asked to select the period of time they expected those symptoms to persist. RESULTS: In both the Greek and Edmontonian groups, the pattern of symptoms anticipated closely resembled the acute symptoms commonly reported by accident victims with acute neck sprain, but while up to 50% of Edmontonians also anticipated symptoms to last months or years, very few Greek subjects selected any symptoms as likely to persist. CONCLUSIONS: In Greece, despite the documented occurrence of neck sprain symptoms in individuals following motor vehicle collisions, there is a very low rate of expectation of any sequelae from this injury. What current or previous aspects of society that underlie this remain uncertain. This lack of expectation of chronicity in Greece may, in part, determine the low prevalence of the chronic whiplash syndrome there. Further studies of symptom expectation as an etiologic factor in the chronic whiplash syndrome are needed.

Accidents, Traffic↗
PubMedDate not supplied

Intermittent cervical traction for cervical radiculopathy caused by large-volume herniated disks.

OBJECTIVE: To describe the use of intermittent cervical traction in managing 4 patients with cervical radiculopathy and large-volume herniated disks. CLINICAL FEATURES: Four patients had neck pain radiating to the arm. The clinical examination was typical in all cases for radiculopathy of cervical origin. Magnetic resonance imaging (MRI) of the cervical spine revealed large-volume herniated disks in all patients. INTERVENTIONS AND OUTCOME: The treatment consisted of intermittent on-the-door cervical traction under the supervision of our physiotherapists. Complete symptom resolution for each patient occurred within 3 weeks. One patient who had an episode of recurrence 16 months after the first treatment was successfully managed again with cervical traction and physiotherapy. CONCLUSION: Cervical spine traction could be considered as a therapy of choice for radiculopathy caused by herniated disks, even in cases of large-volume herniated disks or recurrent episodes.

Adult↗