Faculty Bibliography

BACKGROUND: Abetalipoproteinemia is a rare disorder of fat absorption, characterized by vitamin deficiency, acanthocytosis, and neurologic symptoms including ataxia and tremor. CASE REPORT: A 41-year-old male with abetalipoproteinemia is presented. He underwent staged bilateral thalamic deep brain stimulation (DBS) for the treatment of his tremors. After DBS, the patient achieved significant improvements in his tremors, ataxia, and quality of life. DISCUSSION: Thalamic DBS proved to be both safe and efficacious in the management of ataxia and tremors in a patient with abetalipoproteinemia. This is the first report of DBS in abetalipoproteinemia in the literature.

INTRODUCTION: Cluster headache is a headache syndrome characterized by periodic episodes of intense headache with spontaneous remission. There are recent reports utilizing occipital nerve stimulation for the successful management of medically refractory cases of cluster headache. METHODS: The case of an 18-year-old boy with chronic, refractory, recurrent cluster headaches is presented. He was treated surgically with combined occipital, supraorbital, and infraorbital nerve stimulation. RESULTS: Prior to operation, the patient suffered three to four episodes of cluster headache per day, for four years. After implantation of occipital, supraorbital, and infraorbital nerve stimulators, the patient averages at most three to four headaches per month, at 36-month follow-up. CONCLUSION: Peripheral neurostimulation is safe and efficacious in the management of chronic, medically refractory cluster headache syndrome. The efficacy of treatment was found to be persistent after three years.

Chronic occipital and suboccipital headache is a common symptom in patients with Chiari I malformation (CMI). These headaches may persist despite appropriate surgical treatment of the underlying pathology via suboccipital decompression, duraplasty and related procedures. Occipital stimulation has been shown to be effective in the treatment of a variety of occipital headache/pain syndromes. We present our series of 18 patients with CMI and persistent occipital headaches who underwent occipital neurostimulator trials and, following successful trials, permanent stimulator placement. Seventy-two percent (13/18) of patients had a successful stimulator trial and proceeded to permanent implant. Of those implanted, 11/13 (85%) reported continued pain relief at a mean follow-up of 23 months. Device-related complications requiring additional surgeries occurred in 31% of patients. Occipital neuromodulation may provide significant long-term pain relief in selected CMI patients with persistent occipital pain. Larger and longer-term studies are needed to further define appropriate patient selection criteria as well as to refine the surgical technique to minimize device-related complications.

BACKGROUND: Peripheral nerve stimulation for chronic pain states is a safe and efficacious technique, being used with increasing frequency. The incidence of hardware-related complications requiring revision remains high. OBJECTIVES: The authors describe a technique of distal to proximal neurostimulator lead revision, which does not require the changing of generators or extension leads, and thus presumably will minimize further device-related complications. METHODS: The authors present a case series of 3 patients where the distal to proximal neurostimulator lead revision technique was utilized. RESULTS: The technique was well tolerated in each instance and all patients reported >50% pain reduction at long-term follow-up. CONCLUSIONS: The distal to proximal neurostimulator lead revision technique quickly and safely adjusts lead position, including both lead depth and lead tip location, without a need for replacement of components or revision of the entire system.

Direct central nervous system (CNS) analgesic delivery is a useful option when more traditional means of dealing with chronic pain fail. Solutions containing local anesthetic have been effective in certain disease states, particularly in patients suffering from intractable head and neck pain. This review discusses historical aspects of CNS drug delivery and the role of intrathecal bupivacaine-containing solutions in refractory head and neck pain patients.

We report the successful treatment of an episode of major depression with psychotic features with electroconvulsive therapy (ECT) in a 78-year-old woman with advanced Parkinson disease who had a left subthalamic nucleus deep-brain stimulator (DBS) in place. Electroconvulsive therapy effectively and safely treated the patient's depression without harming the patient or damaging the DBS hardware. We offer additional evidence about the safety and efficacy of electroconvulsive therapy in patients with DBS.

Overactivity of subthalamic nucleus (STN) neurons is a consistent feature of Parkinson's disease (PD) and is a target of therapy for this disorder. However, the relationship of STN firing rate to regional brain function is not known. We scanned 17 PD patients with (18)F-fluorodeoxyglucose (FDG) PET to measure resting glucose metabolism before the implantation of STN deep brain stimulation electrodes. Spontaneous STN firing rates were recorded during surgery and correlated with preoperative regional glucose metabolism on a voxel-by-voxel basis. We also examined the relationship between firing rate and the activity of metabolic brain networks associated with the motor and cognitive manifestations of the disease. Mean firing rates were 47.2 +/- 6.1 and 48.7 +/- 8.5 Hz for the left and right hemispheres, respectively. These measures correlated (P < 0.007) with glucose metabolism in the putamen and globus pallidus, which receive projections from this structure. Significant correlations (P < 0.0005) were also evident in the primary motor (BA4) and dorsolateral prefrontal (BA46/10) cortical areas. The activity of both the motor (P < 0.0001) and the cognitive (P < 0.006) PD-related metabolic networks was elevated in these patients. STN firing rates correlated with the activity of the former (P < 0.007) but not the latter network (P = 0.39). The findings suggest that the functional pathways associated with motor disability in PD are linked to the STN firing rate. These pathways are likely to mediate the clinical benefit that is seen following targeted STN interventions for this disease

Direct neuroaxis drug delivery has expanded the physician's armamentarium to provide treatment options to those who have failed more conservative interventions. Starting from Bier's 'cocainization of the spinal cord' in 1898, direct nervous system pharmacy delivery has long been recognized as an effective means to treat pain. Intrathecal pump systems are now commonplace in the management of numerous pain states, as well as of neuromuscular sequelae of central nervous system injury. There has been much advancement in the physiologic and pharmacologic understanding of direct neuromodulation, providing a growing number of treatment options depending on the specific disease state. As well, surgical techniques and catheter systems have undergone refinements providing improved long-term safety and efficacy. We present a review of the historical evolution to current intrathecal therapies, as well as a dialog regarding patient selection, drug options, and side effects. Also, included is a discussion of surgical techniques, current delivery options and complications concerning pump placement.

OBJECT: The extension of stereotactic radiosurgery treatment of tumors of the spine has the potential to benefit many patients. As in the early days of cranial stereotactic radiosurgery, however, dose-related efficacy and toxicity are not well understood. The authors report their initial experience with stereotactic radiosurgery of the spine with attention to dose, efficacy, and toxicity. METHODS: All patients who underwent stereotactic radiosurgery of the spine were treated using the Novalis unit at Westchester Medical Center between December 2001 and January 2004 are included in a database consisting of demographics on disease, dose, outcome, and complications. A total of 31 patients (12 men, 19 women; mean age 61 years, median age 63 years) received treatment for 35 tumors. Tumor types included 26 metastases (12 lung, nine breast, five other) and nine primary tumors (four intradural, five extradural). Thoracic tumors were most common (17 metastases and four primary) followed by lumbar tumors (four metastases and four primary). Lesions were treated to the 85 to 90% isodose line with spinal cord doses being less than 50%. The dose per fraction and total dose were selected on the basis of previous treatment (particularly radiation exposure), size of lesion, and proximity to critical structures. CONCLUSIONS: Rapid and significant pain relief was achieved after stereotactic radiosurgery in 32 of 34 treated tumors. In patients treated for metastases, pain was relieved within 72 hours and remained reduced 3 months later. Pain relief was achieved with a single dose as low as 500 cGy. Spinal cord isodoses were less than 50% in all patients except those with intradural tumors (mean single dose to spinal cord 268 cGy and mean total dose to spinal cord 689 cGy). Two patients experienced transient radiculitis (both with a biological equivalent dose (BED) > 60 Gy). One patient who suffered multiple recurrences of a conus ependymoma had permanent neurological deterioration after initial improvement. Pathological evaluation of this lesion at surgery revealed radiation necrosis with some residual/recurrent tumor. No patient experienced other organ toxicity. Stereotactic radiosurgery of the spine is safe at the doses used and provides effective pain relief. In this study, BEDs greater than 60 Gy were associated with an increased risk of radiculitis.