Effects of Tonic Spinal Cord Stimulation on External Mechanical and Thermal Stimuli Perception Using Quantitative Sensory Testing: A Multicenter Stimulation ON-OFF Study on Chronic Pain Patients.

OBJECTIVES: Tonic spinal cord stimulation (SCS) is currently used to treat neuropathic pain. With this type of stimulation, an implantable pulse generator generates electrical paresthesias in the affected area through 1 or more epidural leads. The goal of this study was to evaluate the impact of tonic SCS on the sensory perception of chronic pain patients using quantitative sensory testing (QST). MATERIALS AND METHODS: Forty-eight patients (mean age: 57 y) with chronic leg pain due to failed back surgery syndrome or complex regional pain syndrome treated with SCS were recruited from 3 research centers. Test procedures included 2 sessions (stimulation On or Off), with measures of detection thresholds for heat, touch, vibration, and of pain thresholds for cold, heat, pressure, the assessment of dynamic mechanical allodynia, and temporal pain summation. Three different areas were examined: the most painful area of the most painful limb covered with SCS-induced paresthesias (target area), the contralateral limb, and the ipsilateral upper limb. Wilcoxon signed-rank tests were used to compare the mean difference between On and Off for each QST parameter at each area tested. P-values <0.05 were considered significant. RESULTS: Regarding the mean difference between On and Off, patients felt less touch sensation at the ipsilateral area (-0.4±0.9 g, P=0.0125) and were less sensitive at the contralateral area for temporal pain summation (-4.9±18.1 on Visual Analog Scale 0 to 100, P=0.0056) with SCS. DISCUSSION: It is not clear that the slight changes observed were clinically significant and induced any changes in patients' daily life. Globally, our results suggest that SCS does not have a significant effect on sensory perception.

A Review of Biomarkers Use in Parkinson with Deep Brain Stimulation: A Successful Past Promising a Bright Future.

BACKGROUND: Parkinson disease (PD) remains a common neurodegenerative disorder. Functional neurosurgery largely arose with the introduction of deep brain stimulation (DBS) as a potential option for PD unresponsive to medical management. Biomarkers are clinical and laboratory indicators of therapeutic success or failure. OBJECTIVE: To examine the current and published literature relating to the development and use of biomarkers in monitoring and determining the efficacy of DBS in PD. METHODS: The PubMed database was systematically searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systemic reviews. Studies that examined current or potential biomarkers measurable after DBS were included. Articles from 1952 to date were examined. RESULTS: The initial search identified 49 articles. Thirty articles met the inclusion criteria. Articles were subdivided into those addressing biomarkers with proven clinical usefulness and potential biomarkers that have future application. CONCLUSIONS: Biomarkers have been identified that can help to determine the effect of DBS on patients with PD. Current studies show that there are measured differences in electrophysiologic oscillations, gene expression, neuropeptide levels, metabolic function, inflammatory activity, and others in the central nervous system after DBS in PD. Local field potential and ß-band analysis stand as the clinically proven biomarkers of choice for DBS in PD. Many of the identified changes noted could be implemented as clinically useful biomarkers through which DBS may be monitored. Future studies are needed to determine which noted physiologic changes are most appropriately used as biomarkers and in which contexts they are most helpful.

Diagnostic Work-Up of a Giant Calcified Intracranial Aneurysm: Comparing 4D-CTA and Cerebral Angiogram Findings.

The risks associated with unruptured intracranial aneurysms can be neurologically debilitating and even fatal. Evaluation of these aneurysms is critical for determining what type of intervention is warranted, if at all. Cerebral angiography has long been the gold standard in the evaluation of intracranial aneurysms. However, this diagnostic modality is accompanied by several risks that are made clear to the patient before they consent to the procedure. These risks include the possibility of stroke, groin hematomas, contrast-induced anaphylaxis, contrast nephropathy, and catheter-associated infections. Dynamic CT angiography (4D-CTA) has been studied as an assessment tool for cerebral vasculopathies such as stroke, arteriovenous malformations, and aneurysms. It has been shown that 4D-CTA has the advantage of being less invasive and has a shorter examination time than cerebral angiography. In this article, we present a rare case of a giant calcified aneurysm and compare the findings of a cerebral angiogram and a 4D-CTA study.

Chiari I malformation with underlying pseudotumor cerebri: Poor symptom relief following posterior decompression surgery.

INTRODUCTION: Pseudotumor cerebri (PTC) patients exhibit clear clinical signs and symptoms of higher intracranial pressure (ICP) without ventricular enlargement or mass lesions. The clinical picture of patients with PTC can sometimes be similar to that of Chiari Malformation type I (CMI). There is some evidence that Chiari I malformation and PTC may coexist, which raises the question of whether PTC is an idiopathic disease or a complication of posterior decompression surgery-treatment of choice for Chiari I malformation. PRESENTATION OF CASES: A retrospective review of electronic medical records of patients diagnosed with PTC at the University of Toledo Medical Center (UTMC) was performed. The objective was to determine whether PTC patients had a concurrent diagnosis of Chiari I malformation and whether the diagnosis of PTC occurred before or after posterior decompression surgery. Out of the 8 eligible patient medical records reviewed, 5 patients diagnosed with PTC had undergone posterior decompression surgery for Chiari I malformation at anywhere from several days to three years prior to being diagnosed with PTC. The diagnosis of PTC was based on temporary symptomatic relief following lumbar puncture which also showed elevated CSF opening pressures. Finally, a VP shunt was placed in each of the 5 patients to relieve the elevated intracranial pressure which resulted in the complete resolution of the patients' symptoms. DISCUSSION: Our study focuses on patients who were diagnosed with and treated for CMI then reported back to the clinic within several days to three years complaining of symptoms of headache. Upon re-presenting to the clinic, a CSF flow study was performed which showed normal flow of CSF. Then, these patients underwent a lumbar puncture which demonstrated an elevated opening pressure (and ICP) and a temporary relief of the headache with lumbar drainage. A VP shunt was placed for each patient to treat for PTC, and the patients' headaches were relieved. CONCLUSION: This study suggests that the presence of Chiari I malformation in a patient conceals the symptoms of PTC which may become apparent following posterior decompression surgery. Other possibilities could be that the patients are misdiagnosed for Chiari I malformation when they are in fact suffering from PTC, or that PTC is a complication of surgery.

A Comparison of Pharmacologic Therapeutic Agents Used for the Reduction of Intracranial Pressure After Traumatic Brain Injury.

OBJECTIVE: In neurotrauma care, a better understanding of treatments after traumatic brain injury (TBI) has led to a significant decrease in morbidity and mortality in this population. TBI represents a significant medical problem, and complications after TBI are associated with the initial injury and postevent intracranial processes such as increased intracranial pressure and brain edema. Consequently, appropriate therapeutic interventions are required to reduce brain tissue damage and improve cerebral perfusion. We present a contemporary review of literature on the use of pharmacologic therapies to reduce intracranial pressure after TBI and a comparison of their efficacy. METHODS: This review was conducted by PubMed query. Only studies discussing pharmacologic management of patients after TBI were included. This review includes prospective and retrospective studies and includes randomized controlled trials as well as cohort, case-control, observational, and database studies. Systematic literature reviews, meta-analyses, and studies that considered conditions other than TBI or pediatric populations were not included. RESULTS: Review of the literature describing the current pharmacologic treatment for intracranial hypertension after TBI most often discussed the use of hyperosmolar agents such as hypertonic saline and mannitol, sedatives such as fentanyl and propofol, benzodiazepines, and barbiturates. Hypertonic saline is associated with faster resolution of intracranial hypertension and restoration of optimal cerebral hemodynamics, although these advantages did not translate into long-term benefits in morbidity or mortality. In patients refractory to treatment with hyperosmolar therapy, induction of a barbiturate coma can reduce intracranial pressure, although requires close monitoring to prevent adverse events. CONCLUSIONS: Current research suggests that the use of hypertonic saline after TBI is the best option for immediate decrease in intracranial pressure. A better understanding of the efficacy of each treatment option can help to direct treatment algorithms during the critical early hours of trauma care and continue to improve morbidity and mortality after TBI.

Dynamic Four-Dimensional Computed Tomography Angiography for Neurovascular Pathologies.

BACKGROUND: This article illustrates, summarizes, and reviews the multifaceted application of four-dimensional (4D) computed tomography angiography (CTA) in the characterization and diagnosis of various cerebrovascular and tumor-associated vascular pathologies through the presentation of clinical cases, including acute and chronic stroke, arteriovenous malformations, aneurysm, moyamoya disease, and hypervascularity associated with a tumor and its relationship to preoperative embolization. The technical nuances and limitations of the 4D-CTA technique are also discussed. CASE DESCRIPTION: We present 6 cases that best elucidate the application and technical nuances of 4D-CTA and its advantages over traditional digital subtraction angiography. Along with discussion of the utility of 4D-CTA, we also examine the limitations of this technique. CONCLUSIONS: Intracranial vascular lesions can be detected with 4D-CTA and clinically evaluated using information related to vascular flow dynamics. The use of 4D-CTA provides data related to ongoing vascular changes as well as accurate spatial delineation of cerebrovascular pathologies. Overall, 4D-CTA is increasing its role in neuroimaging by providing superior information regarding structural three-dimensional imaging quality and real-time flow.

Considerations in Spinal Fusion Surgery for Chronic Lumbar Pain: Psychosocial Factors, Rating Scales, and Perioperative Patient Education-A Review of the Literature.

OBJECTIVE: Despite widespread use of lumbar spinal fusion as a treatment for back pain, outcomes remain variable. Optimizing patient selection can help to reduce adverse outcomes. This literature review was conducted to better understand factors associated with optimal postoperative results after lumbar spinal fusion for chronic back pain and current tools used for evaluation. METHODS: The PubMed database was searched for clinical trials related to psychosocial determinants of outcome after lumbar spinal fusion surgery; evaluation of commonly used patient subjective outcome measures; and perioperative cognitive, behavioral, and educational therapies. Reference lists of included studies were also searched by hand for additional studies meeting inclusion and exclusion criteria. RESULTS: Patients' perception of good health before surgery and low cardiovascular comorbidity predict improved postoperative physical functional capacity and greater patient satisfaction. Depression, tobacco use, and litigation predict poorer outcomes after lumbar fusion. Incorporation of cognitive-behavioral therapy perioperatively can address these psychosocial risk factors and improve outcomes. The 36-Item Short Form Health Survey, European Quality of Life five dimensions questionnaire, visual analog pain scale, brief pain inventory, and Oswestry Disability Index can provide specific feedback to track patient progress and are important to understand when evaluating the current literature. CONCLUSIONS: This review summarizes current information and explains commonly used assessment tools to guide clinicians in decision making when caring for patients with lower back pain. When determining a treatment algorithm, physicians must consider predictive psychosocial factors. Use of perioperative cognitive-behavioral therapy and patient education can improve outcomes after lumbar spinal fusion.

Densitometric comparison of 3 occipital regions for suitability of fixation.

OBJECTIVE: Atlantooccipital fixation is an important technique in the treatment of upper cervical spine instability. Important considerations for implant devices are obtrusiveness and propagation of torque through the device caused by cervical rotation. The authors evaluated the feasibility of 3 regions of the occiput as sites for occipitocervical fixation by examining bone mineral density at these locations. METHODS: Unembalmed occiputs of 9 male and 4 female cadavers were used (mean age at time of death was 61.6 years, range 36-68 years). Studies were undertaken using caliper measurements and dual-energy x-ray absorptiometry of the superior nuchal line (SNL), the external occipital protuberance (EOP), and the inferior nuchal line (INL). RESULTS: Data indicate that the bone at the INL has a similar volumetric bone density as the bone at the SNL, despite having half the thickness. Also, the volumetric bone density increases laterally along the nuchal lines. CONCLUSIONS: Most hardware fixation is centered on stabilization at the EOP and the SNL. On the basis of these radiological results, the INL shows promise as a potential alternative site for screw placement in occipitocervical fixation.

Superior vena cava syndrome with retropharyngeal edema as a complication of ventriculoatrial shunt.

Thirty-seven-year old female with hydrocephalus managed by a ventriculoatrial (VA) shunt presented with upper body edema, dysphagia, and headache. Imaging demonstrated thrombosis of the superior vena cava (SVC). Direct catheter thrombolysis led to resolution of thrombus burden. Superior vena cava thrombosis is a rare consequence of VA shunting and must be managed emergently.

A rare case of intramedullary 'whorling-sclerosing' variant meningioma.

A 52-year-old man with a seven-year history of progressive weakness, gait problems, and pain in his extremities presented with subacute worsening of his symptoms. Examination revealed weakness in all four extremities, increased tone, hyperreflexia, and sensory deficits. MRI of the cervical spine showed an area of signal abnormality and abnormal enhancement within the cervical cord at the C5-C6 level. The patient initially underwent biopsy followed a few days later by a debulking surgery. Postoperatively, the patient showed improvement in strength as well as ambulation. Intraoperatively, the lesion was confirmed to be intramedullary without any dural attachments. Histopathological examination revealed an extensively hyalinized tumor with sparse collections of cells that were immunopositive for both cytokeratin and GFAP, and immunonegative for EMA and progesterone receptor. This is an unusual pattern of expression, with cytokeratin immunopositivity suggesting a meningioma and GFAP immunopositivity suggesting a glioma. Considering the combination of extensive hyalinization with cytokeratin positivity the tumor was thought to be most consistent with a hyalinized meningioma with GFAP positivity. GFAP-positive meningiomas are rare, and these include the recently described 'whorling-sclerosing' variant. Only three cases of this tumor have been previously reported, all of which were intracranial. This is the first reported case of an intramedullary whorling-sclerosing meningioma.

Treatment of post-dural puncture headache using epidural injection of fibrin sealant as an alternative to autologous epidural blood patch (case report).

Background Post dural puncture headache (PDPH) is an iatrogenic cause of patient morbidity in pain management after spinal or epidural anaesthesia, as well as after diagnostic lumbar puncture. Most patients respond to conservative treatment or to epidural blood patch, yet limited options for effective treatment are available for patients who fail these treatments or present with theoretical contraindication. Case report We present a case of a patient with previously diagnosed human immunodeficiency virus and hepatitis C, who presented with signs of PDPH, which placed him at a theoretical risk of meningeal seeding of the virus during the blood patching procedure. Conclusion We successfully treated the post dural puncture headache and avoided the risk of viral seeding of the meninges by using a fibrin sealant.

Craniofacial trauma and double epidural hematomas from horse training.

INTRODUCTION: A case of complex poly-trauma requiring multi-service management of rare, diagnoses is reviewed. PRESENTATION OF CASE: A healthy 20 year old female suffered double epidural hematoma, base of, skull fracture, traumatic cranial nerve X palsy, benign positional paroxysmal vertigo and supraorbital, neuralgia following equestrian injury. DISCUSSION: Epidemiology, differential diagnosis, and principles of management for each condition, are reviewed. CONCLUSION: Coordinated trauma care is well suited to address the complex poly trauma following, equestrian injury.

Primary CNS lymphoplasmacytic lymphoma: a case report and review of literature.

Lymphoplasmacytic lymphoma is a chronic lymphoproliferative disorder characterized by a proliferation of plasma cells, small lymphocytes, plasmacytoid lymphocytes and the production of monoclonal IgM. Primary central nervous system lymphomas (PCNSL) are rare non-Hodgkin lymphomas (NHL) that can be found in the brain, leptomeninges, eyes or spinal cord, and are mostly intracerebral. PCNSLs constitute 3-4% of primary brain tumors, and in most cases are diffuse large B-cell lymphomas (DLBCL).(1) Low grade lymphomas as primary central nervous system (CNS) lymphoma are very rare. We present here a case report of a woman who presented with headache and was found to have primary intracranial lymphoplasmacytic lymphoma (LPL).