Biomedical subjects

Benjamin Carson

Publications and source records attributed to Benjamin Carson.

5 recordsLinked to original sources

PubMed2006

Adjustable vs set-pressure valves decrease the risk of proximal shunt obstruction in the treatment of pediatric hydrocephalus.

INTRODUCTION: The use of programmable shunt valves has increased dramatically in the practice of pediatric hydrocephalus. Despite theoretical advantages, it remains unclear if the use of programmable vs set-pressure valves affects shunt outcome. MATERIALS AND METHODS: The clinical and radiological records of all pediatric patients undergoing ventriculoperitoneal (VP), ventriculopleural (VPl), and ventriculoatrial (VA) shunt surgery from 2001 to 2004 at an academic institution were reviewed. The association of programmable vs set-pressure valves with subsequent shunt revision was assessed by Kaplan-Meier shunt survival plots and log-rank analysis. RESULTS: A total of 279 VP, VPl, and VA shunt surgeries were performed on patients with median (interquartile range) age of 4 (1-14) years (161 male, 118 female; 158 communicating, 122 obstructive hydrocephalus). Programmable valves were used in 76 (27%) cases and set-pressure valves in 203 (73%). At mean+/-SD follow-up of 17 +/- 13 months, programmable vs set-pressure valves were associated with reduced risk of both overall shunt revision [26 (35%) vs 109 (54%); relative risk (RR) (95% CI); 0.61 (0.41-0.91), p = 0.016] and proximal obstruction [9 (12%) vs 58 (28%); RR (95% CI); 0.39 (0.27-0.80), p = 0.006]. There was no difference in distal obstruction [3 (4%) vs 11 (5%) cases], infection [6 (8%) vs 12 (6%) cases], valve obstruction [0 (0%) vs 4 (2%)], or shunt disconnection [2 (3%) vs 1 (1%)] between adjustable and set-pressure valves, respectively. CONCLUSION: In our experience, the use of programmable vales was associated with a decreased risk of proximal shunt obstruction and shunt revision. Programmable valves may be preferred in patients frequently experiencing proximal shunt failure. A prospective, controlled study is warranted to evaluate the potential value of adjustable vs set-pressure valve systems.

Adolescent↗

PubMed2006

Proton magnetic resonance spectroscopic imaging to differentiate between nonneoplastic lesions and brain tumors in children.

PURPOSE: To investigate whether in vivo proton magnetic resonance spectroscopic imaging (MRSI) can differentiate between 1) tumors and nonneoplastic brain lesions, and 2) high- and low-grade tumors in children. MATERIALS AND METHODS: Thirty-two children (20 males and 12 females, mean age = 10 +/- 5 years) with primary brain lesions were evaluated retrospectively. Nineteen patients had a neuropathologically confirmed brain tumor, and 13 patients had a benign lesion. Multislice proton MRSI was performed at TE = 280 msec. Ratios of N-acetyl aspartate/choline (NAA/Cho), NAA/creatine (Cr), and Cho/Cr were evaluated in the lesion and the contralateral hemisphere. Normalized lesion peak areas (Cho(norm), Cr(norm), and NAA(norm)) expressed relative to the contralateral hemisphere were also calculated. Discriminant function analysis was used for statistical evaluation. RESULTS: Considering all possible combinations of metabolite ratios, the best discriminant function to differentiate between nonneoplastic lesions and brain tumors was found to include only the ratio of Cho/Cr (Wilks' lambda, P = 0.012; 78.1% of original grouped cases correctly classified). The best discriminant function to differentiate between high- and low-grade tumors included the ratios of NAA/Cr and Cho(norm) (Wilks' lambda, P = 0.001; 89.5% of original grouped cases correctly classified). Cr levels in low-grade tumors were slightly lower than or comparable to control regions and ranged from 53% to 165% of the control values in high-grade tumors. CONCLUSION: Proton MRSI may have a promising role in differentiating pediatric brain lesions, and an important diagnostic value, particularly for inoperable or inaccessible lesions.

Adolescent↗

PubMed2005

Effect of antibiotic-impregnated shunt catheters in decreasing the incidence of shunt infection in the treatment of hydrocephalus.

OBJECT: The majority of shunt infections occur within 6 months of shunt placement and chiefly result from perioperative colonization of shunt components by skin flora. Antibiotic-impregnated shunt (AIS) systems have been designed to prevent such colonization. In this study, the authors evaluate the incidence of shunt infection after introduction of an AIS system in a population of children with hydrocephalus. METHODS: The authors retrospectively reviewed all pediatric patients who had undergone cerebrospinal fluid (CSF) shunt insertion at their institution over a 3-year period between April 2001 and March 2004. During the 18 months prior to October 2002, all CSF shunts included standard, nonimpregnated catheters. During the 18 months after October 2002, all CSF shunts included antibiotic-impregnated catheters. All patients were followed up for 6 months after shunt surgery, and all shunt-related complications, including shunt infection, were evaluated. The independent association of AIS catheter use with subsequent shunt infection was assessed via multivariate proportional hazards regression analysis. A total of 211 pediatric patients underwent 353 shunt placement procedures. In the 18 months prior to October 2002, 208 (59%) shunts were placed with nonimpregnated catheters; 145 (41%) shunts were placed with AIS catheters in the 18 months after October 2002. Of patients with nonimpregnated catheters, 25 (12%) experienced shunt infection, whereas only two patients (1.4%) with antibiotic-impregnated catheters experienced shunt infection within the 6-month follow-up period (p < 0.01). Adjusting for intercohort differences via multivariate analysis, AIS catheters were independently associated with a 2.4-fold decreased likelihood of shunt infection. CONCLUSIONS: The AIS catheter significantly reduced incidence of CSF shunt infection in children with hydrocephalus during the early postoperative period (< 6 months). The AIS system used is an effective instrument to prevent perioperative colonization of CSF shunt components.

Adolescent↗

PubMed2005

Ventriculoperitoneal shunt malfunction presenting with pleuritic chest pain.

BACKGROUND: Ventriculoperitoneal (VP) shunts are widely used for treating hydrocephalus. These devices are prone to malfunction with up to 70% requiring revision. Shunt infection and obstruction comprise the majority of malfunctions and usually present dramatically. However, rare presentations occur. METHODS/RESULTS: We report a rare case of VP shunt malfunction presenting with pleuritic chest pain. A 13-year-old girl with a VP shunt placed at birth for congenital hydrocephalus presented on multiple occasions with pleuritic chest pain, cough, and fever. She was diagnosed with an upper respiratory tract infection and discharged home. She returned with respiratory compromise, and chest x-ray depicted the shunt catheter in the pleural space with an associated pleural effusion and infiltrate. The patient fully recovered with intravenous antibiotics, thoracentesis, and placement of a new shunt system. CONCLUSIONS: VP shunt malfunction usually presents with signs and symptoms of increased intracranial pressure and/or infection. However, unusual presentations of malfunction may occur with signs and symptoms which appear unrelated to the shunt. Thus, all patients with VP shunts warrant a comprehensive evaluation.

Adolescent↗

PubMed2003

Auditory processing studied prospectively in two hemidecorticectomy patients.

Auditory processing of speech and nonspeech sounds was studied prospectively in two hemidecorticectomy patients (ages 10-11 years) with Rasmussen's syndrome. We tested auditory word recognition under four listening conditions: in quiet, in noise, after acoustic filtering, and dichotically. Recognition of environmental sounds and discrimination of tones and digitized syllables were also tested. Presurgical testing confirmed normal processing of speech and nonspeech, for both patients, under all listening conditon. One year after surgery, both patients demonstrated intact recognition of words and environmental sounds in quiet but impaired word recognition in noise. The left hemidecorticectomy patient also demonstrated impaired recognition of low-pass filtered words. These findings suggest that either hemisphere can process speech or nonspeech sounds in quiet, whereas both hemispheres are needed to process speech in background noise. Hemispheric contributions to processing speech in noise appear to differ, with the left hemisphere compensating for loss of phonologic information and the right hemisphere compensating for increased attention demands.

Acoustic Stimulation↗