Cory Toth

Deep brain stimulation for intractable pain: a 15-year experience.

OBJECTIVEnDuring the past 15 years, we prospectively followed 68 patients with chronic pain syndromes who underwent deep brain stimulation (DBS). The objective of our study was to analyze the long-term outcomes to clarify patient selection criteria for DBS.nnnMETHODSnPatients were referred from a multidisciplinary pain clinic after conservative treatment failed. Electrodes for DBS were implanted within the periventricular gray matter, specific sensory thalamic nuclei, or the internal capsule. Each patient was followed on a 6-monthly follow-up basis and evaluated with a modified visual analog scale.nnnRESULTSnFollow-up periods ranged from 6 months to 15 years, with an average follow-up period of 78 months. The mean age of the 54 men and 14 women in the study was 51.3 years. Indications for DBS included 43 patients with failed back syndrome, 6 with peripheral neuropathy or radiculopathy, 5 with thalamic pain, 4 with trigeminal neuropathy, 3 with traumatic spinal cord lesions, 2 with causalgic pain, 1 with phantom limb pain, and 1 with carcinoma pain. After initial screening, 53 of 68 patients (77%) elected internalization of their devices; 42 of the 53 (79%) continue to receive adequate relief of pain. Therefore, effective pain control was achieved in 42 of 68 of our initially referred patients (62%). Patients with failed back syndrome, trigeminal neuropathy, and peripheral neuropathy fared well with DBS, whereas those with thalamic pain, spinal cord injury, and postherpetic neuralgia did poorly.nnnCONCLUSIONnDBS in selected patients provides long-term effective pain control with few side effects or complications.

Epidural spinal cord stimulation for treatment of chronic pain—some predictors of success. A 15-year experience

BACKGROUNDnWe have used epidural spinal cord stimulation (SCS) for pain control for the past 15 years. An analysis of our series of 235 patients has clarified the value of specific prognostic parameters in the prediction of successful SCS.nnnMETHODSnPatients were followed up for periods ranging from 6 months to 15 years with a mean follow-up of 66 months. The mean age of the 150 men and 85 women in the study was 51.4 years. Indications for SCS included failed back syndrome (114 patients), peripheral vascular disease (39 patients), peripheral neuropathy (30 patients), multiple sclerosis (13 patients), reflex sympathetic dystrophy (13 patients), and other etiologies of chronic intractable pain (26 patients).nnnRESULTSnOne hundred and eighty-nine patients received permanent devices; 111 (59%) of these patients continue to receive satisfactory pain relief. Pain attributable to failed back syndrome, reflex sympathetic dystrophy, peripheral vascular disease of lower limbs, multiple sclerosis, and peripheral neuropathy responded favorably to spinal cord stimulation. In contrast, paraplegic pain, cauda equina syndrome, stump pain, phantom limb pain, and primary bone and joint disease pain did not respond as well. Cases of cauda equina injury had promising initial pain relief, but gradually declined after a few years. After long-term follow-up, 47 of the 111 successfully implanted patients were gainfully employed, compared with 22 patients before implantation. The successful patients reported improvements in daily living as well as a decrease in analgesic usage. Multipolar stimulation systems were significantly more reliable (p < 0.001) than unipolar systems. Complications included hardware malfunction, electrode displacement, infection, and tolerance.nnnCONCLUSIONnAside from etiologies of pain syndromes as a prognostic factor, we have identified other parameters of success. In patients who have undergone previous surgical procedures, the shorter the duration of time to implantation, the greater the rate of success (p < 0.001). The diagnosis of failed back syndrome must be considered a confounding factor in our analysis. Those patients whose pain did not follow a surgical procedure had better responses to SCS than patients who had multiple surgical procedures prior to their first implant. The advent of multipolar systems has significantly improved clinical reliability over unipolar systems. Age, sex, and laterality of pain did not prove to be of significance.

Spinal cord stimulation is effective in the management of reflex sympathetic dystrophy.

OBJECTIVE: The purpose of this study was to determine the efficacy of spinal cord stimulation (SCS) in patients with symptoms of reflex sympathetic dystrophy (RSD), a disabling clinical condition with significant consequences of morbidity and loss of productivity. METHODS: We have used epidural SCS for pain control during the past 15 years. An analysis of our records revealed 12 consecutive patients diagnosed as having RSD before undergoing SCS. Eight of the 12 patients had undergone previous ablative sympathectomy. The mean age of the nine men and three women was 38.2 years. All suffered extremity injuries from a variety of causes. RESULTS: All 12 patients experienced relief of pain after trial stimulation and had their systems permanently implanted. At an average of 41 months follow-up, all patients were using their stimulators regularly and only two were receiving adjunctive minor pain medication. The level of pain present pre- and postoperatively was determined by administering a modified McGill Pain Questionnaire and a visual analog scale to each patient. Eight patients reported excellent pain relief, and four patients described good results. Five minor complications occurred. CONCLUSION: SCS is an effective treatment for the pain of RSD, including recurrent pain after ablative sympathectomy. The low morbidity of this procedure and its efficacy in patients with refractory pain related to RSD suggest that SCS is superior to ablative sympathectomy in the management of RSD.

Headache secondary to deep brain implantation

This article examines the headaches that can develop with deep brain stimulation. We identified 15 (23.4%) of 64 patients who developed chronic headaches following implantation of deep brain stimulation electrodes for relief of chronic pain syndromes. Electrodes were implanted in the periaqueductal gray, sensory thalamus, and internal capsule. None of these 15 patients reported similar headaches prior to the implantation. Although 5 patients were intermittent headache sufferers prior to implantation, they reported post‐implantation headaches to be completely different in nature. Our experience suggests that headache syndromes may arise due to disturbance of serotonergic neurotransmission within deep brain structures.

Spinal cord stimulation for chronic pain in peripheral neuropathy

BACKGROUNDnSpinal cord stimulation (SCS) has been used for the relief of chronic, intractable pain for over 2 decades. Recent technologic improvements in hardware have resulted in improved clinical outcome. We report our experience with epidural spinal cord stimulation for pain control of peripheral neuropathy for the past 15 years.nnnMETHODSnAn analysis of our series of 276 patients revealed 30 patients diagnosed with peripheral neuropathy. The mean age of the 16 men and 14 women in the study was 62.4 years. The anatomic sources of pain included thorax, as well as upper and lower limbs. Causes of intractable pain included postherpetic neuralgia, intercostal neuralgia, causalgic pain, diabetic neuropathy, and idiopathic neuropathy.nnnRESULTSnNineteen patients reported relief of pain on trial stimulation and had their systems permanently implanted. At an average of 87 months follow-up, 14 of these patients achieved long-term success in control of chronic pain (47% of all patients included in this study). Six patients reported excellent pain relief (> 75% pain relief), eight described good results (> 50% pain relief), and six had poor pain relief (< 50% pain relief).nnnCONCLUSIONnSCS is an effective therapy for pain syndromes associated with peripheral neuropathy. Causalgic and diabetic neuropathic pain seem to respond relatively well. whereas postherpetic pain and intercostal neuralgia syndromes seem to respond less favorably to the long-term beneficial effects of SCS. This information will be useful in the selection of patients with peripheral neuropathic pain who could be helped by SCS.

Wernicke's encephalopathy following gastroplasty for morbid obesity.

BACKGROUNDnThe syndrome of Wernickes encephalopathy consists of two of four features of (1) dietary deficiency; (2) oculomotor abnormality; (3) cerebellar dysfunction; and (4) confusion or mild memory impairment. Predisposing risk factors include alcoholism, hyperemesis gravidarum and prolonged intravenous feeding.nnnMETHODSnA 35-year-old female developed refractory emesis, severe weight loss, and hypokalemia following banded gastroplasty for morbid obesity. Reversal of gastroplasty was performed four months following initial surgery. Following reversal, the patient developed confusion, ataxia, leg weakness and nystagmus.nnnRESULTSnExamination of the patient demonstrated disorientation with confusion, vertical nystagmus worse on downgaze, diffuse weakness of the lower extremities, and bilateral dysmetria. Magnetic resonance imaging of the brain demonstrated symmetrical areas of increased T2 signal present bilaterally in the medial thalamic nuclei. The patient did not demonstrate any initial improvement with intravenous thiamine but improved over two months of follow-up.nnnCONCLUSIONnWernickes encephalopathy has been reported in the European literature as a complication of gastroplasty, with rare recognition of this clinical entity in the North American literature. This potential complication of gastroplasty may be preventable by nutritional intervention in subjects experiencing severe weight loss and emesis following surgery.

Neonatal herpes encephalitis: a case series and review of clinical presentation.

OBJECTIVEnTo describe the clinical and laboratory findings in cases of neonatal herpes simplex virus (HSV) encephalitis.nnnBACKGROUNDnNeonatal HSV encephalitis is a devastating infection which requires a high degree of clinical suspicion and rapid initiation of antiviral therapy.nnnMETHODSnWe performed a retrospective search for all cases of HSV encephalitis within the two Saskatchewan pediatric tertiary care centers for the period of 1985-2001. Only those patients with consistent clinical presentations along with direct evidence of presence of HSV, such as positive cerebrospinal fluid (CSF) viral cultures, positive polymerase chain reaction (PCR) for HSV from CSF, or positive immunoglobulin G against HSV from neonatal blood, were selected.nnnRESULTSnFive male and four female infant patients were identified. At a mean age of presentation of 24 +/- 20 days, seizures occurred in six neonates, lethargy in six neonates, temperature changes in five neonates, and apnea in three neonates. Examination of CSF demonstrated an initial monocytosis or lymphocytosis, elevated CSF protein and depressed CSF glucose in 100% of patients. Electroencephalography (EEG) was abnormal in 100% of patients. Initial computerized tomography was abnormal in 55% of patients. Clinical follow-up over an average of two years demonstrated developmental delay in four patients and upper motor neuron findings in four patients. No patients suffered from postencephalitic epilepsy or mortality.nnnCONCLUSIONSnNeonatal HSV encephalitis most commonly presents with seizures, lethargy, and dysthermia. Cerebrospinal fluid testing and EEG have 100% sensitivity in cases with laboratory confirmation of HSV presence. Improvements in morbidity and mortality as compared to previous reports may relate to better recognition of this illness and acyclovir therapy. The lack of postinfection epilepsy in our series may also relate to better recognition and acyclovir therapy within this series of patients.

Pseudomigraine With Lymphocytic Pleocytosis: A Calcium Channelopathy? Clinical Description of 10 Cases and Genetic Analysis of the Familial Hemiplegic Migraine Gene CACNA1A

Objective.—To report the clinical findings of 10 patients diagnosed with pseudomigraine with lymphocytic pleocytosis and the results of mutational analysis of the CACNA1A gene in 8 of these patients.

Recurrence of Migraine With Aura Due to Tacrolimus Therapy in a Liver Transplant Recipient Successfully Treated With Sirolimus Substitution

We report the case of a female liver transplant recipient who developed a recurrence of severe migraine with aura while on tacrolimus therapy with subsequent remission of headache following discontinuation of tacrolimus and substitution with sirolimus therapy. Headaches in transplant‐recipient patients have become a new area of interest for headache specialists. In particular, immunosuppressant medications such as cyclosporine, tacrolimus, sirolimus, and OKT3 have been associated with development of headache syndromes in the transplant patient, exacerbation of previous headaches syndromes, and development of encephalopathies including headache as a clinical feature.

Persistent cerebrospinal fluid abnormalities in the syndrome of headache, neurological deficit, and cerebrospinal fluid lymphocytosis despite resolution of clinical symptomatology.

This syndrome was described in seven patients who experienced multiple, self-limited, discrete episodes of headache followed by neurological deficit and CSF lymphocytosis. None of these patients described prior headache syndromes, and all cases were selflimited and occurred over less than 3 months. The title of HaNDL syndrome was created in 1995 by Berg and Williams, 2 and additional patients have been described with this syndrome, 3 which has been recognized as a distinct benign headache syndrome. The most common features of this syndrome have been reported as a temporary neurological deficit followed by a severe headache with CSF lymphocytosis identified on lumbar puncture (LP). The syndrome has always been reported to be self-limited and has consisted of a series of episodes, often with different neurological deficits during each episode. Other findings have included an increased CSF protein, an increased opening pressure on LP, transient focal electroencephalographic changes, and a viral prodrome. 2 At the time of clinical symptomatology CSF changes have been well documented. 2,3 However, the occurrence of CSF abnormalities after resolution of the clinical presentation has not been studied previously.This study examined a series of patients with a diagnosis of HaNDL for changes in CSF that occur during the clinical period of symptomatology and during the period of clinical remission.