Chronic neuropathic pain is a debilitating disease process associated with several medical disorders. Different from pain caused by inflammation, neuropathic pain is a diffuse pain disorder often found to be recalcitrant to the limited medical treatments available. Intractable nerve pain may benefit from other therapies capable of longer-lasting pain coverage or greater efficacy. A growing number of reports have emerged suggesting a role for stem cells as a cellular delivery source with neuroprotective agents opposing the effects of nerve damage. Here, the authors review the current experimental therapies examining the use of stem cells for the treatment of neuropathic pain disorders.
Sudhakar Vadivelu, Matthew Willsey, Daniel J. Curry and John W. McDonald III
Jennylee S. Swallow, Jacob R. Joseph, Kylene Willsey, Andrea A. Almeida, Matthew T. Lorincz, Paul Park, Nicholas J. Szerlip and Steven P. Broglio
The authors of recent concussion guidelines have sought to form a consensus on injury management, but it is unclear if they have been effective in conveying this information to the public. Many parents and athletes obtain medical recommendations via the Internet. This review is aimed at evaluating consistency between online resources and published guideline statements in postconcussion return-to-play (RTP) decisions.
Five websites were selected through a Google search for RTP after concussion, including a federal government institution (Centers for Disease Control and Prevention) website, a national high school association (National Federation of State High School Associations) website, a popular nationally recognized medical website for patients (WebMD), a popular parent-driven website for parents of children who participate in sports (MomsTeam), and the website of a private concussion clinic (Sports Concussion Institute), along with a university hospital website (University of Michigan Medicine). Eight specific items from the Zurich Sport Concussion Consensus Statement 2012 were used as the gold standard for RTP recommendations. Three independent reviewers graded each website for each of the 8 recommendations (A = states guideline recommendations appropriately; B = mentions guideline recommendation; C = does not mention guideline recommendation; F = makes inappropriate recommendation).
A grade of A was assigned for 45.8% of the recommendations, B for 25.0%, C for 25.0%, and F for 4.2%. All the websites were assigned an A grade for the recommendation of no RTP on the day of injury. Only 1 website (WebMD) mentioned medication usage in conjunction with the Zurich statement, and only 2 websites (Sports Concussion Institute and University of Michigan Medicine) mentioned appropriate management of persistent symptoms. None of these websites commented correctly on all 8 guideline recommendations.
Online resources are inconsistent in relaying guideline recommendations for RTP and provide a potential source of confusion in the management of concussion for athletes and their parents, which can result in inappropriate RTP decisions.
P. Troy Henning, Thomas J. Wilson, Matthew Willsey, Jessin K. John, Miriana Popadich and Lynda J. S. Yang
Surgical transection of sensory nerves in the treatment of intractable neuropathic pain is a commonly performed procedure. At times these cases can be particularly challenging when encountering obese patients, when targeting deeper nerves or those with a variable branching pattern, or in the case of repeat operations. In this case series, the authors describe their experience with ultrasound-guided surgical instrument placement during transection of a saphenous nerve in the region of prior vascular surgery in 1 patient and in the lateral femoral cutaneous nerve in 2 obese patients. The authors also describe this novel technique and provide pilot data that suggests ultrasound-assisted surgery may allow for complex cases to be completed in an expedited fashion through smaller incisions.
Matthew S. Willsey, Kelly L. Collins, Erin C. Conrad, Heather A. Chubb and Parag G. Patil
Trigeminal neuralgia (TN) is an uncommon idiopathic facial pain syndrome. To assist in diagnosis, treatment, and research, TN is often classified as type 1 (TN1) when pain is primarily paroxysmal and episodic or type 2 (TN2) when pain is primarily constant in character. Recently, diffusion tensor imaging (DTI) has revealed microstructural changes in the symptomatic trigeminal root and root entry zone of patients with unilateral TN. In this study, the authors explored the differences in DTI parameters between subcategories of TN, specifically TN1 and TN2, in the pontine segment of the trigeminal tract.
The authors enrolled 8 patients with unilateral TN1, 7 patients with unilateral TN2, and 23 asymptomatic controls. Patients underwent DTI with parameter measurements in a region of interest within the pontine segment of the trigeminal tract. DTI parameters were compared between groups.
In the pontine segment, the radial diffusivity (p = 0.0049) and apparent diffusion coefficient (p = 0.023) values in TN1 patients were increased compared to the values in TN2 patients and controls. The DTI measures in TN2 were not statistically significant from those in controls. When comparing the symptomatic to asymptomatic sides in TN1 patients, radial diffusivity was increased (p = 0.025) and fractional anisotropy was decreased (p = 0.044) in the symptomatic sides. The apparent diffusion coefficient was increased, with a trend toward statistical significance (p = 0.066).
Noninvasive DTI analysis of patients with TN may lead to improved diagnosis of TN subtypes (e.g., TN1 and TN2) and improve patient selection for surgical intervention. DTI measurements may also provide insights into prognosis after intervention, as TN1 patients are known to have better surgical outcomes than TN2 patients.
Jacob R. Joseph, Jennylee S. Swallow, Kylene Willsey, Andrea A. Almeida, Matthew T. Lorincz, Robert K. Fraumann, Mark E. Oppenlander, Nicholas J. Szerlip and Steven P. Broglio
Previous studies have shown that clinically asymptomatic high-acceleration head impacts (HHIs) may be associated with neuronal and axonal injury, as measured by advanced imaging and biomarkers. Unfortunately, these methods of measurement are time-consuming, invasive, and costly. A quick noninvasive measurement tool is needed to aid studies of head injury and its biological impact. Quantitative pupillometry is a potential objective, rapid, noninvasive measurement tool that may be used to assess the neurological effects of HHIs. In this study, the authors investigated the effect of HHIs on pupillary metrics, as measured using a pupillometer, in the absence of a diagnosed concussion.
A prospective observational cohort study involving 18 high school football athletes was performed. These athletes were monitored for both the frequency and magnitude of head impacts that they sustained throughout a playing season by using the Head Impact Telemetry System. An HHI was defined as an impact exceeding 95g linear acceleration and 3760 rad/sec2 rotational acceleration. Pupillary assessments were performed at baseline, midseason, after occurrence of an HHI, and at the end of the season by using the NeurOptics NPi-200 pupillometer. The Sport Concussion Assessment Tool, 5th Edition (SCAT5), was also used at each time point. Comparisons of data obtained at the various time points were calculated using a repeated-measures analysis of variance and a t-test.
Seven athletes sustained HHIs without a related diagnosed concussion. Following these HHIs, the athletes demonstrated decreases in pupil dilation velocity (mean difference 0.139 mm/sec; p = 0.048), percent change in pupil diameter (mean difference 3.643%; p = 0.002), and maximum constriction velocity (mean difference 0.744 mm/sec; p = 0.010), compared to measurements obtained at the athletes’ own midseason evaluations. No significant changes occurred between the SCAT5 subtest scores calculated at midseason and those after a high impact, although the effect sizes (Cohen’s d) on individual components ranged from 0.41 to 0.65.
Measurable changes in pupil response were demonstrated following an HHI. These results suggest that clinically asymptomatic HHIs may affect brain reflex pathways, reflecting a biological injury previously seen when more invasive methods were applied.