Influence of cochlear parameters on the current practice in cochlear implantation : Development of a concept for personalized medicine.

Since the introduction of cochlear implants into clinical routine, the interest in measuring cochlear parameters, particularly the cochlear duct length (CDL) has increased, since these can have an influence on the correct selection of the electrode. On the one hand, coverage of an optimal frequency band is relevant for a good audiological result, and on the other hand, cochlear trauma due to too deep insertion or displacement of the electrode must be avoided. Cochlear implants stimulate the spiral ganglion cells (SGC). The number of SGC and particularly their distribution can also have an influence on the function of a cochlear implant. In addition, the frequency assignment of each electrode contact can play a decisive role in the postoperative success, since the frequency distribution of the human cochlea with varying CDL shows substantial interindividual differences. The aim of this work is to provide an overview of the methods used to determine the cochlear parameters as well as of relevant studies on the CDL, the number and distribution of SGZ, and the frequency assignment of electrode contacts. Based on this, a concept for individualized cochlear implantation will be presented. In summary, this work should help to promote individualized medicine in the field of cochlear implants in the future, in order to overcome current limitations and optimize audiological outcomes.

[Influence of cochlear parameters on the current practice in cochlear implantation : Development of a concept for personalized medicine. German version]. / Einfluss cochleärer Parameter auf die aktuelle Cochleaimplantatversorgung : Entwicklung eines Konzepts für die personalisierte Medizin.

Since the introduction of cochlear implants into clinical routine, the interest in measuring cochlear parameters, particularly the cochlear duct length (CDL) has increased, since these can have an influence on the correct selection of the electrode. On the one hand, coverage of an optimal frequency band is relevant for a good audiological result, and on the other hand, cochlear trauma due to too deep insertion or displacement of the electrode must be avoided. Cochlear implants stimulate the spiral ganglion cells (SGC). The number of SGC and particularly their distribution can also have an influence on the function of a cochlear implant. In addition, the frequency assignment of each electrode contact can play a decisive role in the postoperative success, since the frequency distribution of the human cochlea with varying CDL shows substantial interindividual differences. The aim of this work is to provide an overview of the methods used to determine the cochlear parameters as well as of relevant studies on the CDL, the number and distribution of SGZ, and the frequency assignment of electrode contacts. Based on this, a concept for individualized cochlear implantation will be presented. In summary, this work should help to promote individualized medicine in the field of cochlear implants in the future, in order to overcome current limitations and optimize audiological outcomes.

Estimated glomerular filtration rate progression in UK primary care patients with type 2 diabetes and diabetic kidney disease: a retrospective cohort study.

AIMS: To examine the rates of diabetic kidney disease (DKD) progression and associated factors, we undertook a study of estimated glomerular filtration rate (eGFR) in a historical cohort of UK primary care patients with type 2 diabetes mellitus (T2DM) and associated DKD from the Clinical Practice Research Datalink. METHODS: Our eligible population were patients with definitive T2DM from a recorded diagnostic code with either a diagnosis of chronic kidney disease (CKD) or renal function test values and renal abnormalities consistent with a CKD diagnosis, identified between 1 October 2006 and 31 December 2011. Only patients with albuminuria results reported in mg/l were used for the longitudinal statistical analyses of the eGFR rate of change using multilevel models. RESULTS: We identified 111,030 patients with T2DM. Among them 58.6% (95% confidence interval (CI): 58.3-58.9) had CKD and 37.2% (95% CI: 36.9-37.5%) had presumed DKD at baseline. Only 19.4% of patients had urinary albumin test results expressed as mg/l in the year prior to index date. Almost two-thirds (63.8%) of patients with T2DM and presumed DKD received prescriptions for angiotensin-converting enzyme (ACE) inhibitors or angiotensin type 1 receptor blockers (ARB) or both. Time-dependent variables that predict subsequent eGFR decline include increased albuminuria, time from index date and older age. CONCLUSION: Only a minority of diabetic patients with DKD had quantitative albuminuria assessments. The relatively low proportion of DKD patients with ACEi or ARB prescriptions suggests a gap between healthcare practice and available scientific evidence during the study period. Increased albuminuria and older age were the most consistent predictors of subsequent eGFR decline.

Inhibition of PKC beta by ruboxistaurin does not enhance the acute blood pressure response to nitroglycerin.

Ruboxistaurin is a selective protein kinase C beta inhibitor undergoing clinical investigation for treatment of diabetic microvascular complications. This study assessed a possible blood pressure (BP) interaction between ruboxistaurin and the exogenous nitric oxide donor, glyceryl trinitrate (GTN). Subjects (N=22) with chronic stable angina received placebo or ruboxistaurin 96 mg/day orally to steady state in a crossover design. Graded GTN (0, 5, 10, 20, 40, 80, and 120 microg/min) or 5% dextrose solution was then infused intravenously and BP was measured following each dose. Ruboxistaurin did not alter the slope of change in standing systolic BP (DeltasSBP/1n[GTN dose]) curve (P=0.272 analysis of covariance) or affect the DeltasSBP at the estimated GTN dose producing a 10-mm Hg reduction in sSBP from baseline on placebo (mean difference -0.9 mm Hg; 95% confidence of interval, -3.3-1.5). In conclusion, ruboxistaurin does not potentiate the acute BP-lowering effects of GTN.

Entirely intracanalicular meningioma: contrast-enhanced MR findings in a rare entity.

We report an unusual case of an entirely intracanalicular meningioma in a 51-year-old woman. Contrast-enhanced MR images showed an enhancing lesion filling the lateral portion of the left internal auditory canal. Our findings suggest that meningiomas should be considered in the differential diagnosis of entirely intracanalicular masses.

Medical complications of head injury.

There are many common and significant medical complications of head injury. These include (1) cardiovascular problems such as hyperdynamic state, myocardial injury, and dysrhythmias; (2) respiratory changes such as neurogenic pulmonary edema, hypoxia, abnormal ventilatory patterns, pulmonary infections, and pulmonary emboli secondary to deep vein thrombosis; (3) consumption coagulopathy; (4) water and electrolyte derangements--hypo- and hypernatremia; (5) hypothalamic/pituitary dysfunction--syndrome of inappropriate secretion of antidiuretic hormone and diabetes insipidus; (6) increased general metabolism with loss of immunocompetence, respiratory compromise, and complications of decreased activity; (7) gastrointestinal difficulties, particularly stress gastritis; and (8) infectious problems including those related to contamination from open wounds and foreign bodies such as monitors.

Prevalence of Paragonimus uterobilateralis infection in children in a Liberian village.

Stool and sputum samples from 127 children in an endemic paragonimiasis area in Liberia, West Africa, were examined for the presence of lung fluke eggs. Samples from nine children (7%) were positive. The eggs were identified as those of Paragonimus uterobilateralis.

Serum antibody levels in human paragonimiasis before and after therapy with praziquantel.

Enzyme immunoassays (ELISA) and indirect haemagglutination (IHA) were used to determine IgG and IgE serum antibody levels in 43 patients from Ecuador before and after therapy with praziquantel. ELISA indicated infection more sensitively than IHA. The tendency of increasing antibody levels between the first and second month after therapy was more distinct when measured by IHA, whereas the decreases of antibody levels between the third and sixth month after treatment was more distinct when measured by ELISA. The IgG ELISA for detecting long persisting antibody was more sensitive than IHA.

Respiratory epithelial cyst of the cerebellopontine angle.

A case of a 29-year-old woman with a cystic lesion in the right cerebellopontine angle, who had three bouts of chemical meningitis in 1 year, is reported. The lesion proved to be a delicate, thin-walled cyst, in part with a squamous lining and in part with a respiratory epithelial (tall, columnar, ciliated, mucus-secreting) lining. Various possibilities to explain this unusual epithelium are explored.

Metrizamide-enhanced computed tomography as an adjunct to metrizamide myelography in the evaluation of lumbar disc herniation and spondylosis.

Eighty patients with operatively proven lumbar disc herniation or lumbar spondylosis were preoperatively evaluated with metrizamide myelography followed by metrizamide-enhanced computed tomography (CT). The x-ray films were reviewed without knowledge of the operative findings, and the patients were subdivided into those with disc extrusions, spondylosis, or recurrent abnormalities. For the group as a whole, CT was correct in 82% and myelography was correct in 77%. Both CT and myelography together were accurate in 91%, a significant improvement (P less than 0.02). The authors conclude that, if both studies are performed, the percentage of cases correctly diagnosed is increased. Therefore, both metrizamide myelography and metrizamide-enhanced CT should be obtained in selected cases. A review of the literature is included.

Clinical, radiographic, and pathological features of symptomatic Rathke's cleft cysts.

The clinical, radiographic, and pathological findings in 155 patients with symptomatic Rathke's cleft cysts are discussed. Eight patients were treated by the authors and 147 were collected in a review of the literature. This lesion occurred more often in female than male patients by a 2:1 margin, and the mean age at presentation was 38 years. The average patient had been symptomatic for nearly 3 years at the time of treatment, with the most common symptoms and signs being pituitary dysfunction, visual disturbances, and headaches. Affected children generally were pituitary dwarfs. The sella was enlarged in 80% of cases, and the cyst was situated in both an intrasellar and a suprasellar location in 71%. Computerized tomography revealed a low-density cystic mass with capsular enhancement in one-half of the cases. A variable appearance was seen with magnetic resonance imaging. Partial excision and drainage of the cyst by the transsphenoidal approach is the recommended treatment, as the recurrence rate is low. Most symptoms and signs improved or resolved following surgery with the exception of hypopituitarism and diabetes insipidus. The cyst lining was usually composed of ciliated cuboidal or columnar epithelium. Theories as to the origin of Rathke's cleft cysts are also discussed.

Intramedullary spinal Histoplasma granuloma. Case report.

While there have been several cases of cerebral histoplasmoma published in the literature, the occurrence of such a lesion in an intramedullary spinal location has not previously been reported. The authors present a patient with a Brown-Séquard lesion secondary to an intramedullary Histoplasma granuloma in the cervical region. The case was successfully managed with surgical removal of the lesion.

Giant cell tumor of the calvaria in a child. Case report.

A giant cell tumor involving the vertex of the skull is described in a 3-year-old child with no history of head trauma. The mass was present approximately 4 months prior to resection. Microscopically, the lesion consisted of highly cellular tissue composed of oval to spindle-shaped stromal cells admixed with numerous multinucleated giant cells. Giant cell tumor of the skull is a rare lesion, usually involving the sphenoid or temporal bone in adults. The differential diagnosis is discussed with reference to the literature regarding giant cell lesions, especially of the cranium. The authors are unaware of previous reports of a similar lesion in this location in such a young child.

Giant intracranial and extracranial cavernous malformation. Case report.

Massive enlargement of an extracerebral cavernous malformation and extension across tissue planes is very uncommon. The authors present the case of a 49-year-old woman with a giant cavernous malformation in the left frontotemporal area. It progressively enlarged during several decades, extended through the calvaria to the extradural space, and was surgically treated. The lesion may have originated in the soft tissue or the skull. The locations of cavernous malformations in various parts of the body are reviewed and their mechanisms of growth are discussed. Surgical excision is the treatment of choice.

Nonoperative treatment of chronic subdural hematoma.

Chronic subdural hematomas that are asymptomatic or producing only mild symptoms are occasionally found with current neuroimaging methods. Some do not progress, and spontaneous resolution can occur. In addition, successful medical treatment of more significant hematomas has been reported. The indications for nonoperative management of these lesions are reviewed in this article.

The role of craniotomy and trephination in the treatment of chronic subdural hematoma.

The treatment of chronic subdural hematoma by craniotomy was the procedure of choice in the early part of this century. It has since been replaced by less invasive techniques but retains a limited role in the management of this condition. A new procedure involving a small craniectomy and marsupialization of the hematoma cavity to the temporalis muscle is described. The results of this treatment compare favorably with the more commonly performed drainage methods.

Transient enlargement of an intracranial aneurysm during pregnancy: case report.

BACKGROUND: The association of intracranial aneurysm and pregnancy is uncommon. Hemodynamic stress plays an important role in the growth of aneurysms. METHODS: The authors report the case of an enlarging cavernous carotid aneurysm in a pregnant 15-year-old young woman. RESULTS: The aneurysm was initially diagnosed prior to the patient's pregnancy by both cross-sectional imaging and cerebral angiography. Further imaging evaluation was required during pregnancy, which demonstrated significant enlargement of the aneurysm. Following delivery, the lesion decreased in size. CONCLUSIONS: We review potential factors associated with pregnancy that may increase hemodynamic stress and influence aneurysm growth. Additionally, the management of pregnancy-related intracranial aneurysms is discussed.

Cranial epidural fibrous tumor associated with hyperostosis: a case report.

This report describes an unusual frontal epidural fibrous tumor in an adult woman. There had been no prior surgical procedure, radiation therapy, or significant head trauma. Microscopically, the lesion consisted of hypocellular, sparsely vascular, dense fibrous tissue. The fibrous mass was accompanied by hyperostosis of the frontal bone. The clinical and pathological characteristics of this lesion are illustrated. The differential diagnosis is discussed with reference to the literature regarding intracranial fibrous lesions. We are unaware of previous report of similar lesions in this location.

Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation: case report.

BACKGROUND: Vertebral artery injury during posterior C1-2 transarticular screw fixation occurs in approximately 3% of patients and may remain asymptomatic or result in arteriovenous fistulae, occlusion, narrowing, or dissection of the vertebral artery, and lead to transient ischemic attacks, stroke, or death. CASE DESCRIPTION: This is the first report of a pseudoaneurysm resulting from damage to the vertebral artery during the procedure. This 31-year-old male underwent posterior C1-2 transarticular screw fixation for unstable os odontoideum. Injury to the left vertebral artery occurred while the hole for the left screw was being drilled. Temporary control of bleeding with local pressure was followed by immediate postoperative angiography that revealed a left vertebral artery pseudoaneurysm. Although the patient remained asymptomatic, therapeutic anticoagulation was instituted 6 hours postoperatively. Increasing size of the pseudoaneurysm was noted on routine follow-up angiography 4 weeks later. Endovascular occlusion of the pseudoaneurysm and left vertebral artery, with preservation of vertebrobasilar flow through the right vertebral artery, was accomplished without neurological consequence. CONCLUSIONS: Vertebral artery pseudoaneurysm complicating posterior C1-2 transarticular screw fixation may be effectively treated with endovascular approaches.

Prophylactic antibiotics with intracranial pressure monitors and external ventricular drains: a review of the evidence.

BACKGROUND: The role of prophylactic antibiotics (PABs) in preventing infections associated with intracranial pressure (ICP) monitors and external ventricular drains (EVD) is not well defined. METHODS: This study includes an analysis of published reports and a survey of current practices regarding the use of PABs with ICP monitors and EVDs. A computerized data search and a review of the abstracts from two major national neurosurgical meetings over the past decade yielded 85 related articles. Three independent investigators, blinded to the title, author(s), institution(s), results, and conclusions of the articles used predetermined inclusion criteria to select studies for meta-analysis. Thirty-six responses were returned from 98 questionnaires (37%) mailed to university neurosurgical programs. RESULTS: Among the articles reviewed, only two studies met the predetermined inclusion criteria for the meta-analysis, and they were of insufficient size to produce statistically significant results. Among the 36 programs that responded to the survey, 26 (72%) used PABs, mainly cephalosporins (46%) and semisynthetic penicillins (38%), with ICP monitors and EVDs. Twenty-two (85%) used one drug, and 4 (15%) used two drugs. Twenty-two (61%) of the total group reported intra-institutional variation in practices among individual staff neurosurgeons. Nineteen (53%) expressed interest in a retrospective study, and 27 (75%) expressed interest in a prospective study on the role of PABs in minor neurosurgical procedures. CONCLUSION: No consensus regarding the use of PABs with ICP monitors and EVDs is noted. Randomized controlled trials of sufficiently large size with appropriate blinding are needed to address this issue.