Wireless high-frequency dorsal root ganglion stimulation for chronic low back pain: A pilot study.

OBJECTIVE: Evaluation of the efficacy of a wireless high-frequency stimulator placed over selected DRG of exiting nerve roots for the treatment of chronic low back pain. DESIGN: Feasibility. SUBJECTS: Six subjects with chronic, intractable back pain refractory to standard medical treatment. METHODS: Four stimulators (Freedom-4A) provided by Stimwave Technologies, were implanted over the DRG exiting nerve roots, bilaterally at both the T9 and L2 vertebral levels. Subjects were asked to evaluate stimulation independently with the devices turned on at T9 and subsequently L2 for each of 2 weeks. Subjects were then monitored for 8 weeks with the preferred stimulator. Pain reduction with the Visual Analog Scale (VAS), functionality with the Oswestry Disability Index (ODI), Patient Global Impression of Change (PGIC) and medication usage were evaluated. RESULTS: Four subjects preferred T9 stimulation with only one subject preferring stimulation at L2. One subject dropped out of the study before conclusion of the 4-week evaluation and is not included in this report. Average pain levels (n = 5) at 12-week post-implantation decreased with 61% for back pain and 56% for leg pain with a significant reduction in pain medication, including a 100% reduction in opioid pain medications. The average reduction in disability was 12%. Subjects reported an average impression of change of 6 (1 = no change, 7 = great deal better). CONCLUSIONS: Wireless high-frequency stimulation of the DRG is a viable option to treat chronic low back pain. Preliminary results show a subject preference for stimulation at the T9 vertebral level.

Occipital neurostimulation for treatment of intractable headache syndromes.

Intractable migraine and other headache syndromes affect almost 40 million Americans and many more millions worldwide. Although many treatment protocols exist, mainly designed around medication regimens, there are estimated to be at least 3-5% of these headache sufferers that do not respond in a meaningful way to medications and whose lives can be severely restricted to darkened, quiet rooms, heavy doses of narcotics, failed personal relationships and an overwhelming sense of hopelessness. In this article, we describe current neuromodulation-based approach to the management of intractable headache.

The future of peripheral nerve neurostimulation.

Electrical stimulation of selected peripheral nerves for treatment of intractable pain has been used inconsistently over the past 30 years due to difficulties in clarifying appropriate indications, utilizing approved device technology, and standardizing the surgical techniques. Circumferential electrodes treating mononeuropathies have given way to paddle electrode techniques and, most recently, the application of percutaneous wire electrode methods will allow for minimally invasive peripheral nerve stimulation for certain intractable CRPS and other painful monoeuropathies.

Stereotastic radiosurgery for glomus jugulare tumors.

OBJECTIVES/HYPOTHESIS: Surgery is considered to be the mainstay of treatment for glomus jugulare tumors. A subset of patients are poor surgical candidates based on age, medical problems, tumor size, or prior treatment failure. The purpose of this study was to review our results with stereotactic radiosurgery (gamma knife treatment) in this group of patients, with particular attention to adverse reactions and symptom relief. STUDY DESIGN: Retrospective review and phone survey. METHODS: Charts were reviewed for size and location of tumor, history of previous treatment, symptoms before and after treatment, amount of radiation received, acute and late complications, and functional level before and after treatment. Pre-treatment and posttreatment magnetic resonance imaging scans were also reviewed. Identified patients were then contacted for a phone interview. RESULTS: Eight patients were identified. Phone interviews were conducted with four patients. Four patients had failed previous treatment. Follow-up ranged from 7 to 104 months. One patient experienced an acute complication: intractable vertigo requiring hospitalization. No patient experienced delayed cranial neuropathies. No patient reported worsening of any of the following symptoms: pulsatile tinnitus, hearing loss, facial weakness, hoarseness, or difficulty swallowing. Three patients reported improvement in their pulsatile tinnitus. Two patients reported improvement in hearing loss, and one patient each reported improvement in vertigo and difficulty swallowing. CONCLUSIONS: Preliminary results suggest that stereotactic radiosurgery is useful to control symptoms and may be delivered safely in patients with primary or recurrent glomus jugulare tumors who are poor surgical candidates.

Spinal cord stimulation for complex regional pain syndrome: a prospective study of 19 patients at two centers.

Objectives. Prospective studies using specific outcome measures for the treatment of complex regional pain syndromes (CRPS) using spinal cord stimulation are lacking in the literature. The current prospective study followed 19 patients with the objective of analyzing such patients using specific outcome measures including the McGill Pain Rating Index, the Sickness Impact Profile, Oswestry Disability, Beck Depression Inventory, and Visual Analog Scale Scores. Materials and Methods. Nineteen patients are reported as a subgroup enrolled at two centers participating in a multicenter study of efficacy/outcomes of spinal cord stimulation. These patients were specifically identified as having CRPS and followed as a separate group. Specific preimplant and postimplant tests to measure outcome were administered. Results. Statistically significant improvement in the Sickness Impact Profile physical and psychosocial subscales is documented. The McGill Pain Rating Index words chosen and sensory subscale also improved significantly as did Visual Analog Scale scores. The Beck Depression Inventory trended toward significant improvement. Conclusions. Patients with CRPS benefit significantly from the use of spinal cord stimulation, based on average follow-up of 7.9 months.

Peripheral neurostimulation for control of intractable occipital neuralgia.

Objective. To present a novel approach for treatment of intractable occipital neuralgia using percutaneous peripheral nerve electrostimulation techniques. Methods. Thirteen patients underwent 17 implant procedures for medically refractory occipital neuralgia. A subcutaneous electrode placed transversely at the level of C1 across the base of the occipital nerve trunk produced paresthesias and pain relief covering the regions of occipital nerve pain Results. With follow-up ranging from 1-½ to 6 years, 12 patients continue to report good to excellent response with greater than 50% pain control and requiring little or no additional medications. The 13th patient (first in the series) was subsequently explanted following symptom resolution. Conclusions. In patients with medically intractable occipital neuralgia, peripheral nerve electrostimulation subcutaneously at the level of C1 appears to be a reasonable alternative to more invasive surgical procedures following failure of more conservative therapies.

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.

Targeted expression of a dominant-negative FGF receptor mutant in the epidermis of transgenic mice reveals a role of FGF in keratinocyte organization and differentiation.

In this study we used a dominant-negative FGF receptor mutant to block FGF function in a specific tissue of transgenic mice. The mutant receptor, which is known to block signal transduction in cells when co-expressed with wild-type receptors, was targeted to suprabasal keratinocytes using a keratin 10 promoter. The transgene was expressed specifically in the skin and highest expression levels were found in the tail. Expression of the mutant receptor disrupted the organization of epidermal keratinocytes, induced epidermal hyperthickening and resulted in an aberrant expression of keratin 6. This suggests that FGF is essential for the morphogenesis of suprabasal keratinocytes and for the establishment of the normal program of keratinocyte differentiation. Our study demonstrates that dominant-negative growth factor receptors can be used to block selectively the action of a growth factor in specific tissues of transgenic mice.

Hemispheric disconnection syndrome persisting after anterior cerebral artery aneurysm rupture.

Hemispheric disconnection syndrome is a rarely reported sequela of aneurysm rupture. Serial neurobehavioral examinations of such a patient after clipping of a right pericallosal artery that had bled into a large portion of the corpus callosum disclosed defects in interhemispheric transfer of information and competitive movements between the left and right extremities. Although the patient's postoperative memory deficit subsequently resolved, his disconnection syndrome persisted and was primarily responsible for his disability despite otherwise normal neurological findings. We studied a second patient with a hematoma in the genu of the corpus callosum secondary to an arteriovenous malformation (AVM). Although the second patient also exhibited postoperative memory problems, her hemispheric disconnection symptoms were minimal and commensurate with a more circumscribed corpus callosum lesion. Neurobehavioral sequelae of aneurysm or AVM rupture involving the anterior circulation, which may be overlooked in the absence of a detailed examination, can produce persistent disability in many patients.

Reconstruction of the anterior skull base following craniofacial resection.

Reconstruction of the anterior skull base (ASB) following craniofacial resection must seal off the cranial cavity from the upper respiratory tract and provide structural support for the brain. The inferiorly based pericranial flap is strong, pliable, and well vascularized and is especially suited for reconstruction of small-to moderate-sized midline defects of the ASB. Surgical technique of pericranial flap reconstruction used in three cases is described. Indications for this flap and other types of reconstruction are discussed and compared. We believe pericranial flap reconstruction of the ASB is technically easy, cosmetically acceptable, and safe.

Magnetic resonance imaging and computerized tomography in relation to the neurobehavioral sequelae of mild and moderate head injuries.

Twenty patients admitted for minor or moderate closed-head injury were studied to investigate the relationship between magnetic resonance imaging (MRI) and neurobehavioral sequelae. The MRI scans demonstrated 44 more intracranial lesions than did concurrent computerized tomography (CT) scans in 17 patients (85%); most of these lesions were located in the frontal and temporal regions. Estimates of lesion volume based on MRI were frequently greater than with CT; however, MRI disclosed no additional lesions that required surgical evacuation. Neuropsychological assessment during the initial hospitalization revealed deficits in frontal lobe functioning and memory that were related to the size and localization of the lesions as defined by MRI. Follow-up MRI and neuropsychological testing at 1 month (13 cases) and 3 months (six cases) disclosed marked reduction of lesion size paralleled by improvement in cognition and memory. These findings encourage further investigation of the prognostic utility of MRI for the clinical management and rehabilitation of mild or moderate head injury.

Brain stem abscess managed with computed tomography-guided stereotactic aspiration.

The importance of stereotactic aspiration to the successful management of three cases of brain stem abscess is discussed with special reference to the advantages offered over medical treatment alone. Stereotactic aspiration allows evacuation of pus, accurate bacteriological diagnosis, selection of an optimal antibiotic regimen, and instillation of antibiotics directly into the abscess cavity. In two of the three cases described here, the abscess reaccumulated after initial aspiration despite appropriate maximal medical therapy. A repeat aspiration was required before resolution occurred. We conclude that medical management alone is not adequate for some cases of brain stem abscess. There was no morbidity that could be attributed to the procedure, suggesting that the risk of stereotactic aspiration is probably quite low and is likely to be less than the risk of incorrect diagnosis, suboptimal choice of antibiotics, or progression of the lesion despite appropriate maximal medical therapy.

Advances in pediatric neurosurgery.

Pediatric neurosurgery is benefiting greatly from technologic advances in medicine that are enabling earlier and more definitive diagnosis and treatment of a variety of conditions amenable to surgical correction. This article familiarizes the pediatrician with some of the many applications of the new technology as well as some newer concepts of disease management in pediatric neurosurgery.

Computed tomography in herpes simplex encephalitis.

Nine patients with herpes simplex encephalitis examined by CT scan were reviewed. A total of 15 satisfactory scans was analyzed. The majority of our cases had CT scan abnormalities: lucency 63% (5 of 8, one case with suboptimal scan), mass effect 50% (4 of 8), abnormal contrast enhancement 57% (4 of 7). The earliest CT scan finding was lucency, presented in two out of three cases studied within 48 hours following onset of symptoms. The primary role of CT scan is to support the suspected diagnosis of herpes simplex encephalitis as well as to indicate the best site for brain biopsy and to permit early effective treatment with adenine arabinoside.