Search PubMed⌕ Search

Biomedical subjects

Kim J Burchiel

Publications and source records attributed to Kim J Burchiel.

At least 19 recordsLinked to original sources
PubMed2006

Design of an artificial neural network for diagnosis of facial pain syndromes.

A classification scheme for facial pain syndromes describing seven categories has previously been proposed. Based on this classification scheme and a binomial (yes/no) facial pain questionnaire, we have designed and trained an artificial neural network (ANN) and as an initial feasibility assessment of such an ANN system examined its ability to recognize and correctly diagnose patients with different facial pain syndromes. One hundred patients with facial pain were asked to respond to a facial pain questionnaire at the time of their initial visit. After interview, an independent diagnosis was assigned to each patient. The patients' responses to the questionnaire and their diagnoses were input to an ANN. The ANN was able to retrospectively predict the correct diagnosis for 95 of 100 patients (95%), and prospectively determine a correct diagnosis of trigeminal neuralgia Type 1 with 84% sensitivity and 83% specificity in 43 new patients. The ability of the ANN to accurately predict a correct diagnosis for the remaining types of facial pain was limited by our clinic sample size and hence less exposure to those categories. This is the first demonstration of the utilization of an ANN to diagnose facial pain syndromes.

Adult↗
PubMed2006

Automatic microelectrode recording analysis and visualization of the globus pallidus interna and stereotactic trajectory.

Locating deep brain neuronal structures is required to accurately place deep brain stimulation (DBS) electrodes during stereotactic surgery in patients with Parkinson's disease and other movement disorders. This study investigates the efficacy of automatic microelectrode visualization and analysis methods to help neurosurgeons locate target structures more objectively, consistently, and easily during surgery. Ten patients (4 males and 6 females) who underwent bilateral implantation of DBS electrodes in the globus pallidus interna (Gpi), from 2001 to 2003, at the Oregon Health and Science University and the Portland Veterans Administration Medical Center were included. We compared the efficacy of the microelectrode recording signal energy, power spectral density (PSD), marginal probability density (mPDF), autocorrelation function (ACF), and partial ACF. mPDF and PSD estimates most accurately indicated the borders of the GPi target structure.

Aged↗
PubMed2006

Automatic analysis and visualization of microelectrode recording trajectories to the subthalamic nucleus: preliminary results.

Although microelectrode recordings (MER) are commonly used to confirm stereotactic targets during surgery for movement disorders, there is no consensus on whether the additional risks and cost of MER are worth the benefits. This may be due, in part, to the inconsistency and inefficiency of subjective interpretation of MER data that is currently used in practice. We describe several fully automatic visualization methods for MER that efficiently and clearly indicate segments of the microelectrode trajectories with homogeneous neural activity that correspond to expected deep brain nuclei. Specifically we demonstrate that these visualization methods can help identify the subthalamic nucleus in Parkinson's disease patients. These methods have the potential to significantly improve patient outcome by helping neurosurgeons objectively identify target structures more quickly and accurately.

Aged↗
PubMed2006

High-resolution three-dimensional magnetic resonance angiography and three-dimensional spoiled gradient-recalled imaging in the evaluation of neurovascular compression in patients with trigeminal neuralgia: a double-blind pilot study.

OBJECTIVE: To assess the value of high-resolution three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography and gadolinium (Gad)-enhanced 3D spoiled gradient-recalled imaging in the visualization of neurovascular compression in patients with trigeminal neuralgia. METHODS: Forty-eight patients with unilateral trigeminal neuralgia underwent high-resolution 3D TOF MR angiography. After administration of a contrast agent, a 3D spoiled gradient-recalled sequence (3D Gad) was run. Images were reviewed by a radiologist blinded to clinical details. All patients underwent microvascular decompression surgery. Microdissection of the trigeminal nerve and compressing vessels was videotaped during surgery and reviewed by surgeons uninvolved in patient care. Results from neuroradiological studies were then compared with findings on operative videotapes. RESULTS: MR angiography in combination with 3D Gad imaging identified surgically verified neurovascular contact in 42 of 46 (91%) symptomatic nerves. The offending vessel (artery, vein) was correctly identified in 31 of 41 cases (sensitivity, 76%; specificity, 75%). Neurovascular compression was observed in 71% of asymptomatic nerves with a trend toward greater compression severity on the symptomatic nerve (P < 0.09). Agreement between the direction of neurovascular contact defined by 3D TOF MR angiography and 3D Gad and findings at surgery was good (kappa = 0.78; 95% confidence interval, 0.61-0.94). CONCLUSION: Double-blind assessment of surgical and neuroradiological findings confirms that neurovascular compression can be visualized with good sensitivity in patients with trigeminal neuralgia by 3D TOF MR angiography in combination with Gad-enhanced 3D spoiled gradient-recalled sequences. Anatomic relationships defined by this method can be useful in predicting surgical findings.

Adult↗
PubMed2005

Trigeminal neuralgia: definition and classification.

Based on specific, objective, and reproducible criteria, a classification scheme for trigeminal neuralgia (TN) and related facial pain syndromes is proposed. Such a classification scheme is based on information provided in the patient's history and incorporates seven diagnostic criteria, as follows. 1) and 2) Trigeminal neuralgia Types 1 and 2 (TN1 and TN2) refer to idiopathic, spontaneous facial pain that is either predominantly episodic (as in TN1) or constant (as in TN2) in nature. 3) Trigeminal neuropathic pain results from unintentional injury to the trigeminal nerve from trauma or surgery. 4) Trigeminal deafferentation pain results from intentional injury to the nerve by peripheral nerve ablation, gangliolysis, or rhizotomy in an attempt to treat either TN or other related facial pain. 5) Symptomatic TN results from multiple sclerosis. 6) Postherpetic TN follows a cutaneous herpes zoster outbreak in the trigeminal distribution. 7) The category of atypical facial pain is reserved for facial pain secondary to a somatoform pain disorder and requires psychological testing for diagnostic confirmation. The purpose of a classification scheme like this is to advocate a more rigorous, standardized natural history and outcome studies for TN and related facial pain syndromes.

Diagnosis, Differential↗
PubMed2005

Pallidal vs subthalamic nucleus deep brain stimulation in Parkinson disease.

BACKGROUND: Deep brain stimulation (DBS) of the globus pallidus interna (GPi) and subthalamic nucleus (STN) has been reported to relieve motor symptoms and levodopa-induced dyskinesia in patients with advanced Parkinson disease (PD). Although it has been suggested that stimulation of the STN may be superior to stimulation of the GPi, comparative trials are limited. OBJECTIVE: To extend our randomized, blinded pilot comparison of the safety and efficacy of STN and GPi stimulation in patients with advanced PD. DESIGN: This study represents the combined results from our previously published, randomized, blinded, parallel-group pilot study and additional patients enrolled in our single-center extension study. SETTING: Oregon Health and Science University in Portland.Patients Twenty-three patients with idiopathic PD, levodopa-induced dyskinesia, and response fluctuations were randomized to implantation of bilateral GPi or STN stimulators. Patients and evaluating clinicians were blinded to stimulation site. All patients were tested preoperatively while taking and not taking medications and after 3, 6, and 12 months of DBS. MAIN OUTCOME MEASURES: Postoperatively, response of symptoms to DBS, medication, and combined medication and DBS was evaluated. Twenty patients (10 in the GPi group and 10 in the STN group) completed 12-month follow-up. RESULTS: Off-medication Unified Parkinson's Disease Rating Scale motor scores were improved after 12 months of both GPi and STN stimulation (39% vs 48%). Bradykinesia tended to improve more with STN than GPi stimulation. No improvement in on-medication function was observed in either group. Levodopa dose was reduced by 38% in STN stimulation patients compared with 3% in GPi stimulation patients (P = .08). Dyskinesia was reduced by stimulation at both GPi and STN (89% vs 62%). Cognitive and behavioral complications were observed only in combination with STN stimulation. CONCLUSION: Stimulation of either the GPi or STN improves many features of advanced PD. It is premature to exclude GPi as an appropriate target for DBS in patients with advanced disease.

Activities of Daily Living↗
PubMed2004

Treatment of hemiballismus with stereotactic pallidotomy. Case report and review of the literature.

Hemiballismus is a relatively rare movement disorder that is characterized by uncontrolled, random, large-amplitude movements of the limbs. It is usually caused by a vascular lesion that involves the contralateral subthalamic nucleus (STN) (also known as the nucleus hypothalamicus or corpus luysi) and its afferent and efferent pathways. The authors present a case of medically intractable hemiballismus in a 70-year-old woman who was successfully treated with stereotactic posteroventral pallidotomy. In agreement with the data reported earlier by other groups, the microrecording performed during the pallidotomy showed a decreased rate of firing of the pallidal neurons, supporting the theory of impaired excitatory input from the STN to the internal part of the globus pallidus. Stereotactic pallidotomy may be the procedure of choice in the treatment of medically intractable hemiballismus. Intraoperative microrecording significantly improves the precision of the stereotactic targeting and should be considered a standard part of the pallidotomy protocol.

Action Potentials↗
PubMed2004

A method for intraoperative microneurographic recording of unitary activity in the trigeminal ganglion of patients with trigeminal neuralgia.

The etiology of trigeminal neuralgia appears to be vascular compression of the nerve at the root entry zone. However, the physiologic mechanism of trigeminal neuralgia remains uncertain. To gain insight into the pathophysiology of the disorder, we developed a method for intraoperative microneurographic recordings from the trigeminal ganglion of patients with trigeminal neuralgia. The recordings are performed immediately prior to standard percutaneous trigeminal gangliolysis for pain relief. Spontaneous or evoked single- and multi-unit action potential activity can be recorded and the location of receptive fields determined. The method should facilitate the testing of hypotheses concerning the origin of this unique pain disorder.

Action Potentials↗
PubMed2004

Pathophysiology of trigeminal neuralgia: new evidence from a trigeminal ganglion intraoperative microneurographic recording. Case report.

The origin of trigeminal neuralgia (TN) appears to be vascular compression of the trigeminal nerve at the root entry zone; however, the physiological mechanism of this disorder remains uncertain. The authors obtained intraoperative microneurographic recordings from trigeminal ganglion neurons in a patient with TN immediately before percutaneous radiofrequency-induced gangliolysis. Their findings are consistent with the idea that the pain of TN is generated, at least in part, by an abnormal discharge within the peripheral nervous system.

Action Potentials↗
PubMed2004

Peripheral stimulation for treatment of trigeminal postherpetic neuralgia and trigeminal posttraumatic neuropathic pain: a pilot study.

OBJECTIVE: Trigeminal neuropathic pain (TNP) after facial trauma or herpes zoster infection is often refractory to treatment. Peripheral nerve stimulation has been used to treat occipital neuralgia; however, efficacy in controlling facial TNP or postherpetic neuralgia is unknown. A retrospective case series of patients who underwent subcutaneous placement of stimulating electrodes for treatment of V(1) or V(2) TNP secondary to herpetic infection or facial trauma is presented. METHODS: Ten patients received implanted subcutaneous pulse generators and quadripolar electrodes for peripheral stimulation of the trigeminal nerve supraorbital or infraorbital branches. Long-term treatment results were determined by retrospective review of medical records (1998-2003) and by independent observers interviewing patients using a standard questionnaire. Surgical complication rate, preoperative symptom duration, degree of pain relief, preoperative and postoperative work status, postoperative changes in medication usage, and overall degree of therapy satisfaction were assessed. Mean follow-up was 26.6 +/- 4.7 months. RESULTS: Peripheral nerve stimulation provided at least 50% pain relief in 70% of patients with TNP or postherpetic neuralgia. Medication use declined in 70% of patients, and 80% indicated that they were mostly or completely satisfied with treatment overall. There were no treatment failures (<50% pain relief and a lack of decrease in medication use) in the posttraumatic group, and two failures (50%) occurred in the postherpetic group. The complication rate requiring reoperation was 30%. CONCLUSION: Peripheral nerve stimulation of the supraorbital or infraorbital branches of the trigeminal nerve is an effective method for relief of TNP after facial trauma or herpetic infection. A prospective trial using this novel approach to treat these disorders is thus warranted.

Adult↗
PubMed2003

A new classification for facial pain.

PURPOSE: A patient-oriented classification scheme for facial pains commonly encountered in neurosurgical practice is proposed. CONCEPT: This classification is driven principally by the patient's history. RATIONALE: The scheme incorporates descriptions for so-called "atypical" trigeminal neuralgias and facial pains but minimizes the pejorative, accepting that the physiology of neuropathic pains could reasonably encompass a variety of pain sensations, both episodic and constant. Seven diagnostic labels result: trigeminal neuralgia Types 1 and 2 refer to patients with the spontaneous onset of facial pain and either predominant episodic or constant pain, respectively. Trigeminal neuropathic pain results from unintentional injury to the trigeminal nerve from trauma or surgery, whereas trigeminal deafferentation pain results from injury to the nerve by peripheral nerve ablation, gangliolysis, or rhizotomy in an intentional attempt to treat either trigeminal neuralgia or other facial pain. Postherpetic neuralgia follows a cutaneous herpes zoster outbreak (shingles) in the trigeminal distribution, and symptomatic trigeminal neuralgia results from multiple sclerosis. The final category, atypical facial pain, is synonymous with facial pain secondary to a somatoform pain disorder. Atypical facial pain can be suspected but not diagnosed by history and can be diagnosed only with detailed and objective psychological testing. CONCLUSION: This diagnostic classification would allow more rigorous and objective natural history and outcome studies of facial pain in the future.

Classification↗
PubMed2002

Trigeminal neuralgia and other neuropathic pain syndromes of the head and face.

Trigeminal neuralgia is the most common craniofacial pain syndrome of neuropathic origin. Although the diagnosis remains based exclusively on history and symptomatology, modern diagnostic techniques, particularly high-resolution magnetic resonance imaging, provides valuable new insight into the pathophysiology of these cases with additional implications for therapeutic strategies. Other neuropathic syndromes affect the trigeminal nerve and warrant different treatments with varied rates of success. Rarely, neuralgias of other cranial nerves mimic trigeminal neuralgia. Finally, it is imperative to distinguish atypical facial pains from these neuropathic syndromes to avoid unsuccessful therapies.

Facial Nerve Diseases↗
PubMed2002

An analysis of the respective risks of hematoma formation in 361 consecutive morphological and functional stereotactic procedures.

OBJECTIVE: The risk of hematoma formation in stereotactic procedures is generally considered to range between 1 and 4%, and it has been speculated that morphological procedures may have a higher risk of bleeding than functional procedures. METHODS: Between 1989 and 1999, all patients who underwent a stereotactic procedure performed by the same surgeon were enrolled sequentially onto the study. All patients had normal preoperative prothrombin time, partial thromboplastin time, and platelet count. High-resolution computed tomography or magnetic resonance imaging with a 1.5-T machine were used for the target definition. None of the patients had an angiogram before surgery. RESULTS: A total of 361 procedures was performed comprising 175 morphological procedures (139 biopsies, 18 lesion evacuations [cysts, abscesses, and hematomas], and 18 drain implantations) and 186 functional procedures (137 lesions [thalamotomy or pallidotomy], 47 deep brain electrode implantations, and two physiological explorations without lesions or implantations). There were no infections or seizures in either group. Three hematomas (1.7%) occurred in the morphological group, two of them in inflammatory lesions in immunocompromised patients (one death) and one in a pineal tumor. Three hematomas (1.6%) occurred in the functional group (no mortality). There was no statistically significant difference (P > 0.05; Fisher's exact test) in the risk of hematoma formation between morphological and functional stereotactic procedures. The morbidity and mortality related to bleeding also were not statistically different (P > 0.05; Fisher's exact test) between these two groups. CONCLUSION: In this series, the risk of bleeding was not higher for morphological procedures than for functional procedures. This suggests that the risk of bleeding for stereotactic procedures is related more to the patient than to the type of procedure performed. Our study confirms an overall risk of bleeding of 1.7% for any type of stereotactic procedure, resulting in a mortality of 0.3% and a morbidity of 1.4%.

Biopsy↗