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Andrew K. Johnson, Daniel M. Heiferman and Demetrius K. Lopes

Object

The introduction of intracranial stents to aneurysm treatment allows endovascular repair of nearly all aneurysms, but the safety and durability of stent-assisted embolization of middle cerebral artery (MCA) aneurysms is unclear.

Methods

Ninety-one patients with 100 complex MCA aneurysms not amenable to simple coiling were treated with stent-assisted embolization as a first option. Technical and clinical results, initial follow-up imaging, and long-term annual MR angiography (MRA) were reviewed.

Results

Intracranial stents were successfully deployed in all 100 aneurysms. There was 1 case of significant neurological morbidity (1%) and 1 case of death (1%) related to treatment. Initial posttreatment angiography revealed complete occlusion of 48 aneurysms (48%), a residual neck in 21 (21%), and residual aneurysm filling in 31 (31%). Follow-up imaging performed in 85 (90.4%) of a possible 94 aneurysms showed complete occlusion of 77 aneurysms (90.6%), residual neck in 3 (3.5%), and residual filling in 5 (5.9%). Four aneurysms (4.7%) required retreatment. Long-term MRA follow-up revealed stability or progressive thrombosis in 47 (97.9%) of 48 aneurysms. In 11 patients Y-configuration stenting caused only 1 minor complication and provided durable occlusion in all cases.

Conclusions

Stent-assisted techniques increase the number of aneurysms that may be treated endovascularly and represent an acceptable alternative to craniotomy. Stents provided adequate vessel reconstruction, low complication rates, and good long-term occlusion.

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Lee A. Tan, Andrew K. Johnson, Kiffon M. Keigher, Roham Moftakhar and Demetrius K. Lopes

Y-stent–assisted coiling is a technique used by neuroendovascular surgeons to treat complex, wide-necked, bifurcation aneurysms in locations such as basilar tip and middle cerebral artery bifurcation. Several recent studies have demonstrated low complication rate and favorable clinical and angiographic outcomes. The Y-stent technique is illustrated here in detail and the intraoperative nuances are also discussed to minimize potential complications associated with technique.

The video can be found here: http://youtu.be/77pEmqx_fyQ.

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D. Andrew Wilkinson, Kyle Johnson, Hugh J. L. Garton, Karin M. Muraszko and Cormac O. Maher

OBJECTIVE

The goal of this analysis was to define temporal and geographic trends in the surgical treatment of Chiari malformation Type I (CM-I) in a large, privately insured health care network.

METHODS

The authors examined de-identified insurance claims data from a large, privately insured health care network of over 58 million beneficiaries throughout the United States for the period between 2001 and 2014 for all patients undergoing surgical treatment of CM-I. Using a combination of International Classification of Diseases (ICD) diagnosis codes and Current Procedural Terminology (CPT) codes, the authors identified CM-I and associated diagnoses and procedures over a 14-year period, highlighting temporal and geographic trends in the performance of CM-I decompression (CMD) surgery as well as commonly associated procedures.

RESULTS

There were 2434 surgical procedures performed for CMD among the beneficiaries during the 14-year interval; 34% were performed in patients younger than 20 years of age. The rate of CMD increased 51% from the first half to the second half of the study period among younger patients (p < 0.001) and increased 28% among adult patients between 20 and 65 years of age (p < 0.001). A large sex difference was noted among adult patients; 78% of adult patients undergoing CMD were female compared with only 53% of the children. Pediatric patients undergoing CMD were more likely to be white with a higher household net worth. Regional variability was identified among rates of CMD as well. The average annual rate of surgery ranged from 0.8 surgeries per 100,000 insured person-years in the Pacific census division to 2.0 surgeries per 100,000 insured person-years in the East South Central census division.

CONCLUSIONS

Analysis of a large nationwide health care network showed recently increasing rates of CMD in children and adults over the past 14 years.

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Emilie Chamard, Hugo Théoret, Elaine N. Skopelja, Lorie A. Forwell, Andrew M. Johnson and Paul S. Echlin

Object

Despite negative neuroimaging findings using traditional neuroimaging methods such as MRI and CT, sports-related concussions have been shown to cause neurometabolic changes in both the acute and subacute phases of head injury. However, no prospective clinical study has used an independent physician-observer design in the monitoring of these changes. The objective of this study was to evaluate the effects of repetitive concussive and sub-concussive head impacts on neurometabolic concentrations in a prospective study of two Canadian Interuniversity Sports (CIS) ice hockey teams using MR spectroscopy (MRS).

Methods

Forty-five ice hockey players (25 men and 20 women) participated in this study. All participants underwent pre- and postseason MRI, including spectroscopy imaging, using a 3-T MRI machine. The linear combination model was used to quantify the following ratios: glutamate/creatine-phosphocreatine (Cr), myoinositol/Cr, and N-acetylaspartate (NAA)/Cr. Individuals sustaining a medically diagnosed concussion were sent for MRI at 72 hours, 2 weeks, and 2 months after injury.

Results

No statistically significant differences were observed between athletes who were diagnosed with a concussion and athletes who were not clinically diagnosed as sustaining a concussion. Although no statistically significant longitudinal metabolic changes were observed among athletes who were diagnosed with a concussion, the results demonstrated a predictable pattern of initial impairment, followed by a gradual return to ratios that were similar to, but lower than, baseline ratios. No significant pre- to postseason changes were demonstrated among men who were not observed to sustain a concussion. However, a substantively significant decrease in the NAA/Cr ratio was noted among the female hockey players (t(13) = 2.58, p = 0.02, η2 = 0.34).

Conclusions

A key finding in this study, from the standpoint of future research design, is the demonstration of substantively significant metabolic changes among the players who were not diagnosed with a concussion. In addition, it may explain why there are few statistically significant differences demonstrated between players who were diagnosed with a concussion and players who were not diagnosed with a concussion (that is, the potency of the independent variable was diminished by the fact that the group of players not diagnosed with a concussion might be better described as a subgroup of the players who may have sustained a concussion but were not observed and diagnosed with a concussion). This result suggests that definitions of concussion may need to be revisited within sports with high levels of repetitive subconcussive head impacts. Future analysis of these data will examine the relationships between the modes of MRI (diffusion tensor imaging, MRS, and susceptibility-weighted MR imaging) used in this study, along with other more sensitive evaluative techniques. This type of intermodal comparison may improve the identification of concussions that were previously dependent on the unreliable self-reporting of recognized concussion symptomatology by the athlete or on poorly validated neuropsychological tests.

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Michael T. Lawton

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Lee A. Tan, Andrew K. Johnson, Kiffon M. Keigher, Roham Moftakhar and Demetrius K. Lopes

Cerebral arteriovenous malformations (AVMs) have an estimated 2–4% annual risk of hemorrhage. Treatment options for AVMs include microsurgical resection, stereotactic radiosurgery, and endovascular embolization. As endovascular technology and techniques continue to advance and mature, endovascular embolization is becoming an increasingly vital component of AVM treatment not only as a presurgical treatment to reduce microsurgical risks, but also as a stand-alone curative method in some cases. This case illustrates the successful and curative transarterial embolization of a right frontal AVM in a 17-year-old boy with ethylene-vinyl alcohol copolymer (Onyx).

The video can be found here: http://youtu.be/L4hE1MvCZCY.

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Paul S. Echlin, Elaine N. Skopelja, Rachel Worsley, Shiroy B. Dadachanji, D. Rob Lloyd-Smith, Jack A. Taunton, Lorie A. Forwell and Andrew M. Johnson

Object

The primary objective of this study was to measure the incidence of concussion according to a relative number of athlete exposures among 25 male and 20 female varsity ice hockey players. The secondary objective was to present neuropsychological test results between preseason and postseason play and at 72 hours, 2 weeks, and 2 months after concussion.

Methods

Every player underwent baseline assessments using the Sport Concussion Assessment Tool-2 (SCAT2), Immediate Post-Concussion Assessment and Cognitive Test (ImPACT), and MRI. Each regular season and postseason game was observed by 2 independent observers (a physician and a nonphysician observer). Players with a diagnosed concussion were removed from the game, examined in the team physician's office using the SCAT2 and ImPACT, and sent to undergo MRI.

Results

Eleven concussions occurred during the 55 physician-observed games (20%). The incidence of concussion, expressed as number of concussions per 1000 athlete exposures, was 10.70 for men and women combined in regular season play, 11.76 for men and women combined across both the regular season and playoff season, 7.50 for men and 14.93 for women in regular season play, and 8.47 for men across both the regular season and playoff season. One male player experienced repeat concussions. No concussions were reported during practice sessions, and 1 concussion was observed and diagnosed in an exhibition game. Neuropsychological testing suggested no statistically significant preseason/postseason differences between athletes who sustained a physician-diagnosed concussion and athletes who did not sustain a physician-diagnosed concussion on either the ImPACT or SCAT2. The athletes who sustained a physician-diagnosed concussion demonstrated few reliable changes postinjury.

Conclusions

Although the incidence of game-related concussions per 1000 athlete exposures in this study was half the highest rate reported in the authors' previous research, it was 3 times higher than the incidence reported by other authors within the literature concerning men's collegiate ice hockey and 5 times higher than the highest rate previously reported for woman's collegiate ice hockey. Interestingly, the present results suggest a substantively higher incidence of concussion among women (14.93) than men (7.50). The reproducible and significantly higher incidence of concussion among both men and woman ice hockey players, when compared with nonphysician-observed games, suggests a significant underestimation of sports concussion in the scientific literature.

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Christina K. Magill, Amy M. Moore, Ying Yan, Alice Y. Tong, Matthew R. MacEwan, Andrew Yee, Ayato Hayashi, Daniel A. Hunter, Wilson Z. Ray, Philip J. Johnson, Alexander Parsadanian, Terence M. Myckatyn and Susan E. Mackinnon

Object

Glial cell line–derived neurotrophic factor (GDNF) has potent survival effects on central and peripheral nerve populations. The authors examined the differential effects of GDNF following either a sciatic nerve crush injury in mice that overexpressed GDNF in the central or peripheral nervous systems (glial fibrillary acidic protein [GFAP]–GDNF) or in the muscle target (Myo-GDNF).

Methods

Adult mice (GFAP-GDNF, Myo-GDNF, or wild-type [WT] animals) underwent sciatic nerve crush and were evaluated using histomorphometry and muscle force and power testing. Uninjured WT animals served as controls.

Results

In the sciatic nerve crush, the Myo-GDNF mice demonstrated a higher number of nerve fibers, fiber density, and nerve percentage (p < 0.05) at 2 weeks. The early regenerative response did not result in superlative functional recovery. At 3 weeks, GFAP-GDNF animals exhibit fewer nerve fibers, decreased fiber width, and decreased nerve percentage compared with WT and Myo-GDNF mice (p < 0.05). By 6 weeks, there were no significant differences between groups.

Conclusions

Peripheral delivery of GDNF resulted in earlier regeneration following sciatic nerve crush injuries than that with central GDNF delivery. Treatment with neurotrophic factors such as GDNF may offer new possibilities for the treatment of peripheral nerve injury.

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Paul Sean Echlin, Charles H. Tator, Michael D. Cusimano, Robert C. Cantu, Jack E. Taunton, Ross E. G. Upshur, Craig R. Hall, Andrew M. Johnson, Lorie A. Forwell and Elaine N. Skopelja

Object

The objective of this study was to measure the incidence of concussion (scaled relative to number of athlete exposures) and recurrent concussion within 2 teams of fourth-tier junior ice hockey players (16–21 years old) during 1 regular season.

Methods

A prospective cohort study called the Hockey Concussion Education Project was conducted during 1 junior ice hockey regular season (2009–2010) involving 67 male fourth-tier ice hockey players (mean age 18.2 ± 1.2 years, range 16–21 years) from 2 teams. Prior to the start of the season, every player underwent baseline assessments using the Sideline Concussion Assessment Tool 2 (SCAT2) and the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT). The study protocol also required players who entered the study during the season to complete baseline SCAT2 and ImPACT testing. If the protocol was not followed, the postinjury test results of a player without true baseline test results would be compared against previously established age and gender group normative levels. Each regular season game was observed by a qualified physician and at least 1 other neutral nonphysician observer. Players who suffered a suspected concussion were evaluated at the game. If a concussion diagnosis was made, the player was subsequently examined in the physician's office for a full clinical evaluation and the SCAT2 and ImPACT were repeated. Based on these evaluations, players were counseled on the decision of when to return to play. Athlete exposure was defined as 1 game played by 1 athlete.

Results

Twenty-one concussions occurred during the 52 physician-observed games (incidence 21.5 concussions per 1000 athlete exposures). Five players experienced repeat concussions. No concussions were reported during practice sessions. A concussion was diagnosed by the physician in 19 (36.5%) of the 52 observed games. One of the 5 individuals who suffered a repeat concussion sustained his initial concussion in a regular season game that was not observed by a physician, and as a result this single case was not included in the total of 21 total concussions. This initial concussion of the player was identified during baseline testing 2 days after the injury and was subsequently medically diagnosed and treated.

Conclusions

The incidence of game-related concussions (per 100 athlete exposures) in these fourth-tier junior ice hockey players was 7 times higher than the highest rate previously reported in the literature. This difference may be the result of the use of standardized direct physician observation, diagnosis, and subsequent treatment. The results of this study demonstrate the need for follow-up studies involving larger and more diverse sample groups to reflect generalizability of the findings. These follow-up studies should involve other contact sports (for example football and rugby) and also include the full spectrum of gender, age, and skill levels.