Observational clinical studies demonstrate that brain hypoxia is associated with poor outcome after severe traumatic brain injury (TBI). In this study, available medical literature was reviewed to examine whether brain tissue oxygen (PbtO2)-based therapy is associated with improved patient outcome after severe TBI. Clinical studies published between 1993 and 2010 that compared PbtO2-based therapy combined with intracranial and cerebral perfusion pressure (ICP/CPP)-based therapy to ICP/CPP-based therapy alone were identified from electronic databases, Index Medicus, bibliographies of pertinent articles, and expert consultation. For analysis, each selected paper had to have adequate data to determine odds ratios (ORs) and confidence intervals (CIs) of outcome described by the Glasgow outcome score (GOS). Seven studies that compared ICP/CPP and PbtO2- to ICP/CPP-based therapy were identified. There were no randomized studies and no comparison studies in children. Four studies, published in 2003, 2009, and 2010 that included 491 evaluable patients were used in the final analysis. Among patients who received PbtO2-based therapy, 121(38.8%) had unfavorable and 191 (61.2%) had a favorable outcome. Among the patients who received ICP/CPP-based therapy 104 (58.1%) had unfavorable and 75 (41.9%) had a favorable outcome. Overall PbtO2-based therapy was associated with favorable outcome (OR 2.1; 95% CI 1.4-3.1). Summary results suggest that combined ICP/CPP- and PbtO2-based therapy is associated with better outcome after severe TBI than ICP/CPP-based therapy alone. Cross-organizational practice variances cannot be controlled for in this type of review and so we cannot answer whether PbtO2-based therapy improves outcome. However, the potentially large incremental value of PbtO2-based therapy provides justification for a randomized clinical trial.

Obesity remains a pervasive global health problem. While there are a number of nonsurgical and surgical options for treatment, the incidence of obesity continues to increase at an alarming rate. The inability to curtail the growing rise of the obesity epidemic may be related to a combination of increased food availability and palatability. Research into feeding behavior has yielded a number of insights into the homeostatic and reward mechanisms that govern feeding. However, there remains a gap between laboratory investigations of feeding physiology in animals and translation into meaningful treatment options for humans. In addition, laboratory investigation may not be able to recapitulate all aspects of human food consumption. In a landmark pilot study of deep brain stimulation (DBS) of the lateral hypothalamic area for obesity, we found that there was an increase in resting metabolic rate as well as a decreased urge to eat. In this review, the authors will review some of the work relating to feeding physiology and research surrounding two nodes involved in feeding homeostasis, nucleus accumbens (NAc) and hypothalamus, and use this to provide a framework for future investigations of DBS as a viable therapeutic modality for obesity.

Background: Deep brain stimulation (DBS) has emerged in recent years as a novel therapy in the treatment of refractory psychiatric disease, including major depressive disorder (MDD), obsessive-compulsive disorder (OCD), and Tourette's syndrome (TS). Standardized outcome scales were crucial in establishing that DBS was an effective therapy for movement disorders. Objective: In order to better characterize the evidence supporting DBS for various psychiatric diseases, we performed a pooled analysis of those studies which incorporated specific standardized rating scales. Methods: A Medline search was conducted to identify all studies reporting DBS for MDD, OCD, and TS. The search yielded a total of 49 articles, of which 24 were included: 4 related to MDD (n = 48), 10 to OCD (n = 64), and 10 to TS (n = 46). Results: A meta-analysis of DBS for MDD, OCD, and TS in studies employing disease-specific standardized outcome scales showed that the outcome scales all improved in a statistically significant fashion for these psychiatric diseases. Our pooled analysis suggests that DBS for TS has the highest efficacy amongst the psychiatric diseases currently being treated with DBS, followed by OCD and MDD. Conclusion: DBS for psychiatric diseases remains investigational; however, even when studies failing to incorporate standardized outcome scales are excluded, there is statistically significant evidence that DBS can improve symptoms in MDD, OCD, and TS. Standardized disease-specific outcome scales facilitate pooled analysis and should be a required metric in future studies of DBS for psychiatric disease.

In recent literature, there have been case reports of an extremely rare entity characterized by hybrid peripheral nerve tumors consisting of elements of neurofibroma, schwannoma, and/or perineurioma. The authors present a unique case of a patient with multiple painful hybrid tumors with negative genetic testing for neurofibromatosis Type 1 and no clinical evidence of neurofibromatosis Type 2 or schwannomatosis. A 28-year-old woman presented with tentatively diagnosed schwannomatosis. She had painful bilateral retromastoid scalp tumors as well as multiple other painful tumors in the distribution of the saphenous, femoral, and sciatic nerves. Her family history was significant for a paternal grandfather with a solitary schwannoma. The patient underwent multiple surgical procedures for tumor resection, including tumors in the regions of the retromastoid scalp, bilateral sciatic nerves, left femoral nerve, and left axilla. These tumors were examined and evaluated histologically. Within the tumors, components of both neurofibromas and schwannomas were found, even though these 2 peripheral nerve sheath tumors have been long considered to be distinct entities. This case report suggests a distinct syndrome that has not previously been appreciated.

The two most popular models used in anatomical training for residents, clinicians, or surgeons are cadavers and sawbones. The former is extremely costly and difficult to attain due to cost, ethical implications, and availability, while the latter is said to not have the same tactile fidelity or mechanical properties as human bone. This study examined the potential use of 3D-printed phantoms to emulate cadaveric, human vertebrae, in hopes of acting as a future use over cadavers. In so doing, we developed 3D-printed MedPhantom®, with the intended use to offer similar tactile feel, mechanical characteristics, and visual appearance as human bone. In order to quantify tactility, a mechanical test was developed where a 5-mm diameter diamond-coated bur spinning at 75,000 RPM swept across the specimens while continuously recording the resultant forces (N) and moments (N-cm), The bur sweep motion is common in orthopedic surgery and neurosurgery. Since most 3D-prints do not offer internal, trabecular structure similar to bone, an algorithm was written to create a stochastic framework of internal mesh to mimic cancellous bone within an STL (stereolithography) file. The ranges of mesh parameters were chosen after several visits with the neurosurgeons participating in the project. In order to quantify structural combinations of wall thickness, gap sizes, and varying cylindrical radii within a print, 1000 RPM compression test with a 5-mm diamond-coated bur was performed with resultant forces (N). Two sample t-test shows statistical significance that samples are not equal to the vertebrae (p < 0.05). Results from the bur sweep test showed 15% Gypsum® powder mixed with 100% Clear® Formlabs resin and 10% Castable® resin mixed with 90% Clear® resin were nearest to human, cadaveric vertebrae, with the difference of force and moment in the x-direction at only 5 N and 7–9 N-cm, respectively. Structural compression results showed that a 2 mm cortical wall, 4 mm or 5 mm gap size between cylinders inside the structure, and 0.25 mm radius of internal cylinders were the best fit parameters to match human vertebrae.