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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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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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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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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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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.

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Ahmed Nageeb M. Taha, Kadir Erkmen, Ian F. Dunn, Svetlana Pravdenkova and Ossama Al-Mefty

Object

Juxtasellar meningiomas frequently extend into the optic canal. Removing these meningiomas from the optic canal is crucial for favorable visual outcome.

Methods

The authors performed a retrospective analysis of 45 patients with anterior and middle fossa meningiomas with involvement of the optic pathway in whom surgery was performed by the senior author (O.A.M.) during the period from 1993 to 2007. Extent of resection and recurrence rates were determined by pre- and postoperative MR imaging studies. Visual outcomes were evaluated with full ophthalmological examinations performed before and after surgery.

Results

Forty-five patients (31 women and 14 men) were involved in this study; their mean age was 51.6 years. Patients were followed for a mean of 29.8 months (range 6–108 months). No surgery-related death occurred. The average tumor size was 3.1 cm. Total resection of the tumor (Simpson Grade I) was achieved in 32 patients (71.1%). Gross-total resection (Simpson Grades II and III) was achieved in 13 patients (28.9%). Only 1 patient harboring a left cavernous sinus meningioma had tumor recurrence and underwent repeat resection. Meningiomas extended into 58 optic canals in these cases; 13 patients showed extension into both optic canals. Visual disturbance was the main presenting symptom in 37 patients (82.2%); 8 patients had normal vision initially. Visual improvement after surgery was seen in 21 (57%) of 37 patients and in 27 (34.6%) of 78 affected eyes. Vision remained unchanged in 48 (61.5%) of 78 eyes. Transient postoperative visual deterioration occurred in 2 eyes (2.6%), with recovery to baseline over time. Only 1 (1.3%) of 78 eyes had permanent visual deterioration after surgery. The visual outcome was affected mainly by the tumor size, the preoperative visual status, and the duration of symptoms.

Conclusions

Involvement of the optic canal in meningiomas is frequent. It occurs in a wide variety of anterior skull base meningiomas and it can be bilateral. It is a prominent factor that affects the preoperative visual status and postoperative recovery. Decompression of the optic canal and removal of the tumor inside is a crucial step in the surgical management of these tumors to optimize visual recovery and prevent tumor recurrence.

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

Object

Although they provide excellent ventral and lateral exposure of the brainstem, petrosal approaches to brainstem cavernous malformations (CMs) are infrequently reported.

Methods

The authors reviewed their experience with petrosal approaches to brainstem CMs in combination with a comprehensive review of the literature to elucidate resection rates, complication rates, and outcomes.

Results

Including their own results, the authors found 65 cases in 20 reports of brainstem CMs treated with petrosal approaches. The specific approaches were posterior petrosal in 37 cases (57%), anterior petrosal in 17 (26%), extended posterior petrosal in 10 (15%), and a combined petrosal approach in 1 case (2%). For 50 cases in 16 reports with detailed outcome information, the overall complete resection rate was 90%, with early postoperative morbidity reported in 30% of cases and permanent morbidity in 14%. The rate of CSF leakage was 6%.

Conclusions

The versatile petrosal approaches to brainstem CMs are associated with good outcomes and an acceptable morbidity rate. More expansive lesions can be approached using a combination of the standard anterior and posterior petrosal approach, preserving hearing and avoiding the greater complication rates associated with extended posterior petrosal approaches.

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

Complex posterior circulation aneurysms are formidable lesions with an abysmal natural history. Their management continues to present a challenge to both endovascular and open microsurgical approaches. Affording an expansive, combined supra- and infratentorial exposure, the petrosal approaches are well suited for these challenging lesions when located along the basilar trunk or at a low-lying basilar apex. This report evaluates the evolution and application of petrosal approaches to these lesions. Excluding transsigmoid, infratentorial, or labyrinth-sacrificing approaches, the authors found 23 reports with 61 posterior circulation aneurysms treated via a petrosal approach. Although early morbidity was not negligible, rates of aneurysm occlusion (95% overall) and long-term outcome were quite laudable in light of the challenge posed by these lesions. Moreover, with accumulating experience with petrosal approaches, rates of complications are likely to wane, as neurosurgeons capitalize on the expansive exposure afforded by these indispensable approaches.

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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.