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Ian F. Dunn, Gavin Dunn and Arthur L. Day

✓ Neurosurgeons in the last half-century have had considerable influence on modern-day athletics. In this article, the authors address the contributions made by neurosurgeons as clinician–scientists, particularly as these relate to the understanding and reduction of the incidence and severity of injury to the nervous system during athletic competition. American football has been a proving ground for the ability of the craniospinal axis to withstand and, in unfortunate cases, succumb to tremendous impact forces; in this way, it has served as a model for translational research and was the arena in which Dr. Richard Schneider made his greatest contributions to sports neurosurgery. Therefore, in his memory and in the spirit of the Schneider lectureship, the authors outline the notable contribution to modern-day athletics made by neurosurgeons as it applies to American football. Neurosurgeons have had considerable influence on reducing injury severity, and this cause has been championed by a few notable individuals whose efforts are discussed herein.

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Wenya Linda Bi, Vikram C. Prabhu and Ian F. Dunn

The epochal developments in the treatment of meningioma—microsurgery, skull base techniques, and radiation therapy—will be appended to include the rational application of targeted and immune therapeutics, previously ill-fitting concepts for a tumor that has traditionally been a regarded as a surgical disease. The genomic and immunological architecture of these tumors continues to be defined in ever-greater detail. Grade I meningiomas are driven by NF2 alterations or mutations in AKT1, SMO, TRAF7, PIK3CA, KLF4, POLR2A, SUFU, and SMARCB1. Higher-grade tumors, however, are driven nearly exclusively by NF2/chr22 loss and are marked by infrequent targetable mutations, although they may harbor a greater mutation burden overall. TERT mutations may be more common in tumors that progress in histological grade; SMARCE1 alteration has become a signature of the clear cell subtype; and BAP1 in rhabdoid variants may confer sensitivity to pharmacological inhibition. Compared with grade I meningiomas, the most prominent alteration in grade II and III meningiomas is a significant increase in chromosomal gains and losses, or copy number alterations, which may have behavioral implications. Furthermore, integrated genomic analyses suggest phenotypic subgrouping by methylation profile and a specific role for PRC2 complex activation. Lastly, there exists a complex phylogenetic relationship among recurrent high-grade tumors, which continues to underscore a role for the most traditional therapy in our arsenal: surgery.

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Saksham Gupta, Wenya Linda Bi and Ian F. Dunn

Surgery is curative for most meningiomas, but a minority of these tumors recur and progress after resection. Initial trials of medical therapies for meningioma utilized nonspecific cytotoxic chemotherapies. The presence of hormone receptors on meningioma ushered in trials of hormone-mimicking agents. While these trials expanded clinical understanding of meningioma, they ultimately had limited efficacy in managing aggressive lesions. Subsequent detection of misregulated proteins and genomic aberrancies motivated the study of therapies targeting specific biological disturbances observed in meningioma. These advances led to trials of targeted kinase inhibitors and immunotherapies, as well as combinations of these agents together with chemotherapies. Prospective trials currently recruiting participants are testing a diverse range of medical therapies for meningioma, and some studies now require the presence of a specific protein alteration or genetic mutation as an inclusion criterion. Increasing understanding of the unique and heterogeneous nature of meningiomas will continue to spur the development of novel medical therapies for the arsenal against aggressive tumors.

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Ian F. Dunn, Mark R. Proctor and Arthur L. Day

✓Lumbar spine injuries in athletes are not uncommon and usually take the form of a mild muscle strain or sprain. More severe injuries sustained by athletes include disc herniations, spondylolistheses, and various types of fracture. The recognition and management of these injuries in athletes involve the additional consideration that to return to play, the lumbar spine must be able to withstand forces similar to those that were injurious. The authors consider common lumbar spine injuries in athletes and discuss management principles for neurosurgeons that are relevant to this population.

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Urvashi Upadhyay, Rami O. Almefty, Ian F. Dunn and Ossama Al-Mefty

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Bradley A. Gross, Daryoush Tavanaiepour, Rose Du, Ossama Al-Mefty and Ian F. Dunn

In this article, the authors review the history of the posterior petrosal approach. The early foundation of the retrolabyrinthine lateral petrosectomy has its roots in the otolaryngology literature. These early approaches were limited in exposure by the tentorium superiorly and the sigmoid sinus posteriorly. Although the concept of a transtentorial approach was originally combined with a complete labyrinthectomy, Hakuba and colleagues described the expansive exposure afforded by sectioning the tentorium and superior petrosal sinus and mobilizing a skeletonized sigmoid sinus. This maneuver serves as the key step in allowing for the full, combined supra- and infratentorial exposure that the posterior petrosal approach provides. In contrast to Hakuba et al.'s approach, which used a partial labyrinthectomy, modern approaches often preserve the entire labyrinth (retrolabyrinthine approach). For added exposure, the latter can be combined with the anterior petrosal approach, allowing for the preservation of hearing and an enhanced view of the surgical target. The authors review the evolution of the petrosal approach and highlight its applicability.

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Ian F. Dunn and E. Antonio Chiocca

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Ryan Brewster, Wenya Linda Bi, Timothy R. Smith, William B. Gormley, Ian F. Dunn and Edward R. Laws Jr.

Baseball maintains one of the highest impact injury rates in all athletics. A principal causative factor is the “beanball,” referring to a pitch thrown directly at a batter’s head. Frequent morbidities elicited demand for the development of protective gear development in the 20th century. In this setting, Dr. Walter Dandy was commissioned to design a “protective cap” in 1941. His invention became widely adopted by professional baseball and inspired subsequent generations of batting helmets. As a baseball aficionado since his youth, Walter Dandy identified a natural partnership between baseball and medical practice for the reduction of beaning-related brain injuries. This history further supports the unique position of neurosurgeons to leverage clinical insights, inform innovation, and expand service to society.

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Rami Almefty, Ian F. Dunn, Svetlana Pravdenkova, Mohammad Abolfotoh and Ossama Al-Mefty

Object

The relentless natural progression of petroclival meningiomas mandates their treatment. The management of these tumors, however, is challenging. Among the issues debated are goals of treatment, outcomes, and quality of life, appropriate extent of surgical removal, the role of skull base approaches, and the efficacy of combined decompressive surgery and radiosurgery. The authors report on the outcome in a series of patients treated with the goal of total removal.

Methods

The authors conducted a retrospective analysis of 64 cases of petroclival meningiomas operated on by the senior author (O.A.) from 1988 to 2012, strictly defined as those originating medial to the fifth cranial nerve on the upper two-thirds of the clivus. The patients' average age was 49 years; the average tumor size (maximum diameter) was 35.48 ± 10.09 mm (with 59 tumors > 20 mm), and cavernous sinus extension was present in 39 patients. The mean duration of follow-up was 71.57 months (range 4–276 months).

Results

In 42 patients, the operative reports allowed the grading of resection. Grade I resection (tumor, dura, and bone) was achieved in 17 patients (40.4%); there was no recurrence in this group (p = 0.0045). Grade II (tumor, dura) was achieved in 15 patients (36%). There was a statistically significant difference in the rate of recurrence with respect to resection grade (Grades I and II vs other grades, p = 0.0052). In all patients, tumor removal was classified based on postoperative contrast-enhanced MRI, and gross-total resection (GTR) was considered to be achieved if there was no enhancement present; on this basis, GTR was achieved in 41 (64%) of 64 patients, with a significantly lower recurrence rate in these patients than in the group with residual enhancement (p = 0.00348). One patient died from pulmonary embolism after discharge.

The mean Karnofsky Performance Status (KPS) score was 85.31 preoperatively (median 90) and improved on follow-up to 88, with 30 patients (47%) having an improved KPS score on follow-up. Three patients suffered a permanent deficit that significantly affected their KPS. Cerebrospinal fluid leak occurred in 8 patients (12.5%), with 2 of them requiring exploration. Eighty-nine percent of the patients had cranial nerve deficits on presentation; of the 54 patients with more than 2 months of follow-up, 21 (32.8%) had persisting cranial nerve deficits. The overall odds of permanent cranial nerve deficit of treated petroclival meningioma was 6.2%. There was no difference with respect to immediate postoperative cranial nerve deficit in patients who had GTR compared with those who had subtotal resection.

Conclusions

Total removal (Grade I or II resection) of petroclival meningiomas is achievable in 76.4% of cases and is facilitated by the use of skull base approaches, with good outcome and functional status. In cases in which circumstances prevent total removal, residual tumors can be followed until progression is evident, at which point further intervention can be planned.

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Chima O. Ohaegbulam, Ian F. Dunn, Pierre d'Hemecourt and Mark R. Proctor

✓ This report describes 3 young male patients with multiple lumbar spondylolyses in combination with a symptomatic epidural hematoma. The records of all 3 patients were reviewed for clinical details. All patients were successfully treated without surgical intervention. Initial neuroimaging results for all patients revealed epidural hematomas, and follow-up imaging confirmed resolution of the hematomas. The relevant literature is briefly reviewed to examine the rarity of this combination. Spontaneous epidural hematomas may occur in the setting of spondylolysis, and this diagnosis should be considered when imaging reveals an unusual epidural lesion in a young active patient.