Biomedical subjects

K J Burchiel

Publications and source records attributed to K J Burchiel.

At least 37 records · Page 2Linked to original sources

PubMed1999

Efficacy of transverse tripolar stimulation for relief of chronic low back pain: results of a single center.

The goal of this study was to evaluate the efficacy of the transverse tripolar spinal cord stimulation system (TTS) in providing relief of low back pain in patients with chronic non-malignant pain. Transverse tripolar electrodes were implanted in the lower thoracic region (T(8-9) to T(12)-L(1)) in 10 patients with chronic neuropathic pain, all of whom reported a significant component of low back pain in combination with unilateral or bilateral leg pain. One patient reported inadequate pain relief during the trial and was not implanted with a permanent generator. A visual analogue scale of low back pain showed a nonsignificant decrease from 64 +/- 19 to 47 +/- 30 (p = 0.25; paired t test) after 1 month of stimulation. Similarly, functional disability evaluated using Oswestry Low Back Pain Questionnaire was not improved (p = 0. 46; paired t test). We conclude that chronic low back pain is not particularly responsive to the transverse stimulation provided by the TTS system.

Adult↗

PubMed1999

Extensive arachnoid ossification with associated syringomyelia presenting as thoracic myelopathy. Case report and review of the literature.

The authors present the case of progressive thoracic myelopathy caused by the extensive ossification of the arachnoid membrane and associated intramedullary syrinx. Based on their findings and results of the literature search, they describe a pathological basis for this rare condition, discuss its incidence and symptomatology, and suggest a simple classification for various types of the arachnoid ossification. They also discuss the magnetic resonance imaging features of arachnoid ossification and associated spinal cord changes. The particular value of plain computerized tomography, which is highly sensitive in revealing intraspinal calcifications and ossifications, in the diagnostic evaluation of patients with a clinical picture of progressive myelopathy is emphasized.

Arachnoid↗

PubMed1998

Ablative therapy for movement disorders. Complications in the treatment of movement disorders.

Presently, there is a renaissance in the surgical treatment of movement disorders. Prompted by the growing recognition of the limitations of drug therapy, this resurgence has been further promoted by progress in neuronal transplantation, advances in neuroimaging and stereotactic surgical techniques, and innovative therapies, such as deep brain stimulation for abnormal movements. Mortality associated with thalamotomy and pallidotomy is rare, but morbidity is not inconsiderable, particularly in the elderly and those with preexisting brain damage. Judicious patient selection and physiologic confirmation of stereotactic targets are cornerstones to complication avoidance.

Antiparkinson Agents↗

PubMed1997

Tremor control after pallidotomy in patients with Parkinson's disease: correlation with microrecording findings.

The goals of this study were to analyze the effect of pallidotomy on parkinsonian tremor and to ascertain whether an association exists between microrecording findings and tremor outcome. Forty-four patients with Parkinson's disease (PD) who had drug-induced dyskinesia, bradykinesia, rigidity, and tremor underwent posteroventral pallidotomy. Using a 1-micro-tip tungsten electrode, microrecordings were obtained through one to three tracts, starting 10 mm above the pallidal base. Tremor severity was measured on a patient-rated, 100-mm Visual Analog Scale (VAS), both preoperatively and 3 to 9 months (mean 6 months) postoperatively. Preoperatively, tremor was rated as 50 mm or greater in 24 patients (55%) and as less than 25 mm in 13 patients (30%). Postoperatively, tremor was rated as 50 mm or greater in five patients (11%) and less than 25 mm in 29 patients (66%). The difference was significant (p = 0.0001). Four patients (9%) had no postoperative tremor. Tremor improved by at least 50% in eight (80%) of 10 patients in whom tremor-synchronous cells were recorded (Group A) and in 12 (35%) of 34 patients in whom tremor-synchronous cells were not recorded (Group B). This difference was significant (p = 0.03). Tremor improved by at least 50 mm in all (100%) of the seven Group A patients with severe (> or = 50 mm) preoperative tremor and in nine (53%) of 17 Group B patients with severe preoperative tremor. This difference was also significant (p = 0.05). The authors proffer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with PD who have severe (> or = 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.

Journal Article↗

PubMed1997

Infrequent types of pallidal discharges during pallidotomy.

Pallidal discharges of patients with Parkinson's disease have been characterized as slow irregular or bursting discharges for the external pallidal segment (GPe) and fast discharges for the internal pallidal segment (GPi). Tremor-synchronous cells have also been described. Using microrecording techniques on 70 patients who underwent pallidotomy, we have recorded other types of pallidal discharges. In GPe, we recorded cells which fired fast, cells which were silent, and cells which fired tonically. In GPi, we recorded cells which burst following short segments of fast tonic discharges. We will demonstrate these cells and discuss their clinical significance.

Action Potentials↗

PubMed1997

Tremor control after pallidotomy in patients with Parkinson's disease: correlation with microrecording findings.

The goals of this study were to analyze the effect of pallidotomy on parkinsonian tremor and to ascertain whether an association exists between microrecording findings and tremor outcome. Forty-four patients with Parkinson's disease who had drug-induced dyskinesia, bradykinesia, rigidity, and tremor underwent posteroventral pallidotomy. Using a 1-mu-tip tungsten electrode, microrecordings were obtained through one to three tracts, starting 10 mm above the pallidal base. Tremor severity was measured on a patient-rated, 100-mm Visual Analog Scale (VAS), both preoperatively and 3 to 9 months (mean 6 months) postoperatively. Preoperatively, tremor was rated as 50 mm or greater in 24 patients (55%) and as less than 25 mm in 13 patients (30%). Postoperatively, tremor was rated as 50 mm or greater in five patients (11%) and less than 25 mm in 29 patients (66%). The difference was significant (p = 0.0001). Four patients (9%) had no postoperative tremor. Tremor improved by at least 50% in eight (80%) of 10 patients in whom tremor-synchronous cells were recorded (Group A) and in 12 (35%) of 34 patients in whom tremor-synchronous cells were not recorded (Group B). This difference was significant (p = 0.03). Tremor improved by at least 50 mm in all (100%) of the seven Group A patients with severe (> or = 50 mm) preoperative tremor and in nine (53%) of 17 Group B patients with severe preoperative tremor. This difference was also significant (p = 0.05). The authors prefer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with Parkinson's disease who have severe (> or = 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.

Adult↗

PubMed1996

Prospective, multicenter study of spinal cord stimulation for relief of chronic back and extremity pain.

STUDY DESIGN: This prospective, multicenter study was designed to investigate the efficacy and outcome of spinal cord stimulation using a variety of clinical and psychosocial outcome measures. Data were collected before implantation and at regular intervals after implantation. This report focuses on 70 patients who had undergone 1 year of follow-up treatment at the time of data analysis. OBJECTIVES: To provide a more generalizable assessment of long-term spinal cord stimulation outcome by comparing a variety of pain and functional/quality-of-life measures before and after management. This report details results after 1 year of stimulation. SUMMARY OF BACKGROUND DATA: The historically diverse methods, patient selection criteria, and outcome measures reported in the spinal cord stimulation literature have made interpretation and comparison of results difficult. Although short-term outcomes are generally consistent, long-term outcomes of spinal cord stimulation, as determined by prospective studies that assess multidimensional aspects of the pain complaint among a relatively homogeneous population, are not well established. METHODS: Two hundred nineteen patients were entered at six centers throughout the United States. All patients underwent a trial of stimulation before implant of the permanent system. Most were psychologically screened. One hundred eighty-two patients were implanted with a permanent stimulating system. At the time of this report, complete 1-year follow-up data were available on 70 patients, 88% of whom reported pain in the back or lower extremities. Patient evaluation of pain and functional levels was completed before implantation and 3, 6, 12, and 24 months after implantation. Complications, medication usage, and work status also were monitored. RESULTS: All pain and quality-of-life measures showed statistically significant improvement during the treatment year. These included the average pain visual analogue scale, the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Sickness Impact Profile, and the Back Depression Inventory. Overall success of the therapy was defined as at least 50% pain relief and patient assessment of the procedure as fully or partially beneficial and worthwhile. Using this definition, spinal cord stimulation successfully managed pain in 55% of patients on whom 1-year follow-up is available. Complications requiring surgical intervention were reported by 17% (12 of 70) of patients. Medication usage and work status were not changed significantly. CONCLUSIONS: This prospective, multicenter study confirms that spinal cord stimulation can be an effective therapy for management of chronic low back and extremity pain. Significant improvements in many aspects of the pain condition were measured, and complications were minimal.

Adult↗

PubMed1996

Pallidotomy: a survey of current practice in North America.

Twenty-eight centers completed a survey about their current practice of pallidotomy. This sample represents a non-exhaustive survey of the current practice of pallidotomy in North America and is not a study of outcomes. 1015 patients underwent 1219 pallidotomies: 811 (80%) unilateral, 72 (7%) staged bilateral, and 132 (13%) simultaneous bilateral. Pallidotomy has long been an accepted procedure and the indications for this surgery, in the opinion of the responding centers, were rated on a scale of 1 (poor) to 4 (excellent) and demonstrated dyskinesia as the best indication (median = 4); on-off fluctuations, dystonia, rigidity, and bradykinesia as good indications (median = 3); and freezing, tremor and gait disturbance as fair indications (median = 2). Most centers used MRI alone (50%) or in combination with CT scan (n = 6) or ventriculopathy (n = 5) to localize the target. The median values of pallidal coordinates were: 2 mm anterior to the midcommissural point 21 mm lateral to the midsagittal plane and 5 mm below the intercommissural line. Microrecording was performed by half of the centers (n = 14) and half of the remaining centers were considering starting it (n = 7). Main criteria used to define the target included the firing pattern of spontaneous neuronal discharges (n = 13) and the response to joint movement (n = 10). Most centers performed motor (n = 26) and visual (n = 23) macrostimulation. Twenty four centers performed test lesions using median values of 55 degrees C temperatures for 30 s. Final lesions consisted of 3 permanent lesions placed 2 mm apart, each lesion created with median values of 75 degrees C temperatures for 1 minute. Median hospital stay was 2 days.

Brain Mapping↗

PubMed1996

Functional anatomy of the pallidal base in Parkinson's disease.

OBJECTIVE: The purpose of this study is to define the morphology of the boundary between the globus pallidus and the ansa lenticularis (i.e., pallidal base) in humans. This information is important for surgeons who perform pallidotomy. METHODS: Thirty-eight patients with Parkinson's disease underwent pallidotomy using microrecording techniques. The pallidal base was identified by the loss of neuronal single unit activity and by the change in background noise, as analyzed on the audio monitor and by fast Fourier transformation. RESULTS: Three quarters of the patients had an abrupt transition of the background noise from neuronal to axonal activity. One quarter of the patients had multiple successive transitions of the background activity, over a distance of 0.4 to 2 mm (median, 1 mm). CONCLUSION: We conclude that the pallidal base is not a smooth, sharp boundary between the globus pallidus and the ansa lenticularis. We propose two models that define the morphology of the pallidal base. One model depicts the pallidal base as a multifolded boundary that distinctly separates pallidal neurons from ansa lenticularis axons. Another model depicts the pallidal base as an indistinct transitional boundary between the globus pallidus and the ansa lenticularis, which contains axonal fibers intermixed with small clusters of pallidal neurons. We discuss the clinical relevance of these findings.

Adult↗

PubMed1996

MRI distortion and stereotactic neurosurgery using the Cosman-Roberts-Wells and Leksell frames.

When not corrected, geometrically distorted magnetic resonance images may be unsuitable for stereotactic intracranial neurosurgical procedures where accuracy of target localization is critical. On a GE Signa 1.5-tesla system, we implemented an imaging protocol designed to improve the accuracy of the determination of target coordinates by means of multiple scans utilizing reversal of the frequency-encoded readout gradient. Using a Cosman-Roberts-Wells (CRW) frame and a phantom, geometric shifts of important image features were found to occur. In patients undergoing functional neurosurgical procedures with the CRW system, localization of the posterior commissure by corrected MR images was compared to that obtained by intraoperative ventriculography. Unexpectedly, severe distortions in MR images were revealed by the studies, with shifts of some fiducial markers of 10 mm from their estimated true position. Most of this distortion was attributable to the magnetic properties of the stereotactic frame, and could be eliminated by appropriate design and manufacture of the frame system. Images obtained with an MRI-compatible Leksell stereotactic frame were found to be relatively free of major geometric distortion. This study points out that properties of frame systems used for stereotactic neurosurgery may greatly influence the accuracy of frame-based stereotactic neurosurgery, and that the accuracy of these frame systems is testable.

Humans↗

PubMed1996

Characteristics and somatotopic organization of kinesthetic cells in the globus pallidus of patients with Parkinson's disease.

Information is limited on the characteristics and topographic localization of pallidal kinesthetic cells in patients with Parkinson's disease. The authors analyzed the data from 298 neurons recorded in 38 patients with Parkinson's disease who underwent pallidotomy via microrecording techniques. Sixty-five neurons (22%) responded to passive movement of contralateral limbs. Of 17 kinesthetic cells that were tested in six patients, seven (41%) responded to ipsilateral limb movement as well. Nineteen cells (6%) fired synchronously with tremor. More kinesthetic cells were activated (63%) than inhibited (28%) by movement of single (68%) rather than multiple (32%) joints, and proximal (75%) rather than distal (25%) joints. The lateral globus pallidus externus (GPe) and medial globus pallidus internus (GPi) pallidal segments contained similar proportions of kinesthetic cells, activated or inhibited cells, arm- or leg-activated cells, and cells responding to single or multiple joints. Significantly more kinesthetic cells that responded to distal joints were recorded in GPi compared to GPe segments (p = 0.01). Arm and leg cells had similar characteristics pertaining to activation versus inhibition and responses to single, multiple, proximal, or distal joint movements. Arm and leg cells were somatotopically organized in GPi. Arm cells were clustered at the rostral and caudal segments of GPi and leg cells were clustered centrally. In GPe, leg cells were clustered at the caudal border. No somatotopic organization was identified for activated or inhibited cells; cells that responded to single, multiple, proximal, or distal joints; tremor-synchronous cells; or cells responding to specific joints within somatotopic arm or leg cells. It is concluded that kinesthetic cells provide a roadmap that localizes limb cells during pallidotomy. More studies are needed to identify the clinical significance of the different characteristics of kinesthetic cells.

Adult↗

PubMed1996

Anchoring of deep brain stimulation electrodes using a microplate. Technical note.

The authors report a new technique to anchor deep brain stimulation electrodes using a titanium microplate. This technique has been safely used to secure 20 quadripolar deep brain stimulation electrodes implanted for movement disorders (18 electrodes) and pain (two electrodes). Twelve electrodes were implanted in the thalamus, four in the subthalamic nucleus, and four in the pallidum. No electrode migration or rupture occurred, and all electrodes have been shown to work properly after internalization of the system.

Brain↗

PubMed1995

Prognostic factors of spinal cord stimulation for chronic back and leg pain.

Spinal cord stimulation (SCS) has been used for more than 20 years in the treatment of diverse pain conditions. Although recent studies have identified more clearly those conditions for which SCSoffers a favorable prognosis, the identification of a patient population in whom reasonably long-term success can be expected has been difficult. In an effort to improve patient selection and increase the overall success rate of treatment, we have examined various physical, demographic, and psychosocial variables as predictors of SCS outcome. The study population consisted of 40 patients with chronic low back and/or leg pain, 85% of whom were diagnosed with failed back surgery syndrome. Medical history and demographic data were collected as part of an initial assessment along with patient responses to the Minnesota Multiphasic Personality Inventory, the visual analogue pain rating scale (VAS), the McGill Pain Questionnaire, the Oswestry Disability Questionnaire, the Beck Depression Inventory, and the Sickness Impact Profile. Treatment outcomes were examined and found to improve significantly after 3 months of stimulation. Subsequent regression analysis revealed that patient age, the Minnesota Multiphasic Personality Inventory depression subscale D, and the evaluative subscale of the McGill Pain Questionnaire (MPQe) were important predictors of posttreatment pain status. Increased patient age and D subscale scores correlated negatively with pain status, as measured by the percentage of changes in pretreatment and posttreatment VAS scores, % delta VAS. In contrast, higher MPQe correlated with improved pain status. By the use of the following equation and the definition commonly associated with SCS success (at least 50% decrease in the VAS pain level), the success or failure of 3 months of SCS was correctly predicted in 88% of the study population. Our results suggest that patient age, Minnesota Multiphasic Personality Inventory depression, and MPQe may be clinically useful in the prediction of pain status after 3 months of SCS in patients with chronic low back and/or leg pain. % delta VAS = 112.57 - 1.98 (D)-1.68 (Age) + 35.54 (MPQe).

Adult↗

PubMed1995

Thalamotomy for movement disorders.

VL thalamotomy is an excellent choice for the control of tremor in patients with a wide variety of disorders. Parkinson's disease and essential tremor are the best indications, but other disorders also respond. Improvement of bradykinesia and rigidity in Parkinson's disease is achievable but is not as dramatic as hyperkinetic symptoms. Morbidity from thalamotomy is most common with bilateral lesions, and innovative therapies such as thalamic stimulation may have a role when a second contralateral procedure is needed. Thalamotomy is an effective procedure that has probably been underused over the past two decades. With renewed interest in stereotactic neurosurgery, improved imaging, and well-established target localization techniques, the procedure is effective with a high degree of safety. The growing enthusiasm for brain grafting has also stimulated interest in the surgical treatment of movement disorders, and clearly this technique will evolve and progress as well. In the author's opinion, the results of ablative surgery still far exceed those of tissue implantation. For a select group of indications, thalamotomy should be considered in the forefront of options for patients with movement disorders.

Humans↗

PubMed1993

Effects of thalamic stimulation on tremor, balance, and step initiation: a single subject study.

This study was conducted to evaluate the clinically apparent balance improvements in a patient with Parkinson's disease who had stimulating electrodes surgically implanted to the VIM nucleus of the right thalamus for control of left-upper-extremity tremor. Experiments were conducted to determine if balance improved simply because the large-amplitude upper-extremity tremor was reduced or if the neural control of balance improved. Using EMGs and forceplate recordings, we quantified the effects of the thalamic stimulation on the contralateral upper-extremity tremor and on the lower-extremity postural muscle activations for quiet stance, step initiation, and equilibrium responses to surface displacements. The results demonstrated that, beside reducing the amplitude and destabilizing effects of the upper-extremity tremor, the thalamic stimulation was also effective in reducing tremor activity of the trunk and contralateral lower-extremity muscles. In addition, the contralateral lower-extremity muscle activation patterns, strengths, and durations for the balance tasks were enhanced during stimulation. These results suggest that thalamic stimulation improved this patient's balance by reducing tremor in the contralateral extremities and by increasing burst duration and magnitude of the tibialis anterior, which functions as the postural prime mover for the step initiation and balance tasks.

Electric Stimulation Therapy↗

PubMed1993

Painful nerve injuries: bridging the gap between basic neuroscience and neurosurgical treatment.

Pain which followed suspected nerve injury was comprehensively evaluated with detailed examination including history, neurologic exam, electrodiagnostic studies, quantitative sensory testing, thermography, anesthetic and sympathetic nerve blocks. Forty two patients treated surgically fell into four discrete groups: 1) Distal sensory neuromas treated by excision of the neuroma and reimplantation of the proximal nerve into muscle or bone marrow, 2) Suspected distal sensory neuromas in which the involved nerve was sectioned proximal to the injury site and reimplanted, 3) Proximal neuromas-incontinuity of major sensorimotor nerves treated by external neurolysis, and 4) Proximal major sensorimotor nerve injuries at points of anatomic entrapment treated by external neurolysis and transposition, if possible. Patient follow up was possible in 40/42 patients (95%) from 2-32 months (average F/U = 11 mo.). Surgical success was defined as: > or = 50% improvement in pain (VAS) or pain relief subjectively rated as good or excellent, and no postoperative narcotic usage. Overall, 40% (16/40) of patients met those criteria. Success rates varied as follows: Group 1 (n = 18) 44%, Group 2 (n = 10) 40%, Group 3 (n = 5) 0%, and Group 4 (n = 7) 57%. A total of 12 of 40 patients (30%) were employed both pre- and postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromyography↗

PubMed1993

Trigeminal neuropathic pain.

Typical trigeminal neuralgia is characterized by episodic, unilateral, lancinating, triggerable, often shock-like facial pains, and pain-free intervals. Trigeminal neuropathic pain could be defined as constant unilateral facial pain of variable intensity, is non-triggerable, and unremitting. Atypical trigeminal neuralgia is an overlap syndrome with both episodic and constant pain. Patients with clear pathology of the trigeminal system often have sensory loss and atypical pains. The leading theory of causation of typical trigeminal neuralgia points to minimal compression and demyelination at the root entry zone (REZ) of the trigeminal nerve. In the experience of many neurosurgeons, atypical pains result from lesions or injuries of the trigeminal nerve root distal to the REZ. In a review of 122 patients, distal trigeminal pathology correlated with a clinical syndrome of trigeminal neuropathic pain. An hypothesis is presented that peripheral lesions of the trigeminal nerve behave as do other peripheral nerve lesions in that they are associated with sensory loss, deafferentiation and non "tic-like" pains. This may be due to the asynchronous spatial temporal dispersion of abnormal centrally-propagating axonal activity in nociceptive and non-nociceptive fibers from the region of pathology. This is opposed to the putative synchronous multifiber volleys which may emanate from the proximal trigeminal REZ in patients with typical trigeminal neuralgia. It appears that classical trigeminal neuralgia may be an exception to the rule that nerve injuries typically produce symptoms like constant pain and allodynia. Trigeminal neuropathic pain is, in some ways, a more general syndrome in that it is a painful nerve injury of the distal trigeminal nerve.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗

PubMed1993

Abnormal activity in diabetic rat saphenous nerve.

UNLABELLED: This study was conducted to test whether abnormal spontaneous activity similar to that found after peripheral nerve trauma develops in diabetic nerve, and whether duration and/or severity of hyperglycemia affected ongoing activity. We maintained 32 diabetic BB Wistar rats on a euglycemic or hyperglycemic control regimen for 3-15 mo; 22 nondiabetic BB rats served as controls. All animals underwent acute saphenous nerve recordings. Whole nerve conduction velocities in 3- to 6-mo-old euglycemic diabetic rats were not different from controls, but 3- to 6-mo-old hyperglycemic diabetic conduction velocities were slower than in controls (P < 0.001) or euglycemic diabetic rats (P < 0.05). Compared with controls, 9- to 12-mo-old diabetic nerve conduction velocities were slower under both euglycemic (P < 0.029) and hyperglycemic (P < 0.04) regimens, but treatment groups did not differ. Combined 3- to 6-mo-old diabetic rats exhibited less resting sympathetic activity than controls under both euglycemic (P < 0.022) and hyperglycemic (P < 0.001) regimens. Sympathetic activity in 9- to 12-mo-old diabetic rats did not differ from controls. However, less sympathetic activity was found in older controls than in younger ones (P < 0.028). IN CONCLUSION: 1) saphenous nerve conduction velocity was slower in diabetic BB rats than in controls; 2) good glycemic control maintained normal conduction velocity in young adults, but the effect diminished with age; 3) resting sympathetic activity levels in young adult BB rats were lower than controls; and 4) sympathetic activity in old BB rats was diminished whether diabetes was present or not.

Analysis of Variance↗