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Charles A. Miller, Jason H. Boulter, Daniel J. Coughlin, Michael K. Rosner, Chris J. Neal and Michael S. Dirks

OBJECTIVE

Symptomatic cervical spondylosis with or without radiculopathy can ground an active-duty military pilot if left untreated. Surgically treated cervical spondylosis may be a waiverable condition and allow return to flying status, but a waiver is based on expert opinion and not on recent published data. Previous studies on rates of return to active duty status following anterior cervical spine surgery have not differentiated these rates among military specialty occupations. No studies to date have documented the successful return of US military active-duty pilots who have undergone anterior cervical spine surgery with cervical fusion, disc replacement, or a combination of the two. The aim of this study was to identify the rate of return to an active duty flight status among US military pilots who had undergone anterior cervical discectomy and fusion (ACDF) or total disc replacement (TDR) for symptomatic cervical spondylosis.

METHODS

The authors performed a single-center retrospective review of all active duty pilots who had undergone either ACDF or TDR at a military hospital between January 2010 and June 2017. Descriptive statistics were calculated for both groups to evaluate demographics with specific attention to preoperative flight stats, days to recommended clearance by neurosurgery, and days to return to active duty flight status.

RESULTS

Authors identified a total of 812 cases of anterior cervical surgery performed between January 1, 2010, and June 1, 2017, among active duty, reserves, dependents, and Department of Defense/Veterans Affairs patients. There were 581 ACDFs and 231 TDRs. After screening for military occupation and active duty status, there were a total of 22 active duty pilots, among whom were 4 ACDFs, 17 TDRs, and 2 hybrid constructs. One patient required a second surgery. Six (27.3%) of the 22 pilots were nearing the end of their career and electively retired within a year of surgery. Of the remaining 16 pilots, 11 (68.8%) returned to active duty flying status. The average time to be released by the neurosurgeon was 128 days, and the time to return to flying was 287 days. The average follow-up period was 12.3 months.

CONCLUSIONS

Adhering to military service-specific waiver guidelines, military pilots may return to active duty flight status after undergoing ACDF or TDR for symptomatic cervical spondylosis.

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Joshua Chiu, Steve Braunstein, Jean Nakamura, Philip Theodosopoulos, Penny Sneed, Michael McDermott and Lijun Ma

OBJECTIVE

Interfractional residual patient shifts are often observed during the delivery of hypofractionated brain radiosurgery. In this study, the authors developed a robustness treatment planning check procedure to assess the dosimetric effects of residual target shifts on hypofractionated Gamma Knife radiosurgery (GKRS).

METHODS

The residual patient shifts were determined during the simulation process immediately after patient immobilization. To mimic incorporation of residual target shifts during treatment delivery, a quality assurance procedure was developed to sample and shift individual shots according to the residual uncertainties in the prescribed treatment plan. This procedure was tested and demonstrated for 10 hypofractionated GKRS cases.

RESULTS

The maximum residual target shifts were less than 1 mm for the studied cases. When incorporating such shifts, the target coverage varied by 1.9% ± 2.2% (range 0.0%–7.1%) and selectivity varied by 3.6% ± 2.5% (range 1.1%–9.3%). Furthermore, when incorporating extra random shifts on the order of 0.5 mm, the target coverage decreased by as much as 7%, and nonisocentric variation in the dose distributions was noted for the studied cases.

CONCLUSIONS

A pretreatment robustness check procedure was developed and demonstrated for hypofractionated GKRS. Further studies are underway to implement this procedure to assess maximum tolerance levels for individual patient cases.

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Zachary S. Hubbard, Fraser Henderson Jr., Rocco A. Armonda, Alejandro M. Spiotta, Robert Rosenbaum and Fraser Henderson Sr.

On a Sunday morning at 06:22 on October 23, 1983, in Beirut, Lebanon, a semitrailer filled with TNT sped through the guarded barrier into the ground floor of the Civilian Aviation Authority and exploded, killing and wounding US Marines from the 1st Battalion 8th Regiment (2nd Division), as well as the battalion surgeon and deployed corpsmen. The truck bomb explosion, estimated to be the equivalent of 21,000 lbs of TNT, and regarded as the largest nonnuclear explosion since World War II, caused what was then the most lethal single-day death toll for the US Marine Corps since the Battle of Iwo Jima in World War II. Considerable neurological injury resulted from the bombing. Of the 112 survivors, 37 had head injuries, 2 had spinal cord injuries, and 9 had peripheral nerve injuries. Concussion, scalp laceration, and skull fracture were the most common cranial injuries.

Within minutes of the explosion, the Commander Task Force 61/62 Mass Casualty Plan was implemented by personnel aboard the USS Iwo Jima. The wounded were triaged according to standard protocol at the time. Senator Humphreys, chairman of the Preparedness Committee and a corpsman in the Korean War, commented that he had never seen such a well-executed evolution. This was the result of meticulous preparation that included training not only of the medical personnel but also of volunteers from the ship’s company, frequent drilling with other shipboard units, coordination of resources throughout the ship, the presence of a meticulous senior enlisted man who carefully registered each of the wounded, the presence of trained security forces, and a drilled and functioning communication system.

Viewed through the lens of a neurosurgeon, the 1983 bombings and mass casualty event impart important lessons in preparedness. Medical personnel should be trained specifically to handle the kinds of injuries anticipated and should rehearse the mass casualty event on a regular basis using mock-up patients. Neurosurgery staff should participate in training and planning for events alongside other clinicians. Training of nurses, corpsmen, and also nonmedical personnel is essential. In a large-scale evolution, nonmedical personnel may monitor vital signs, work as scribes or stretcher bearers, and run messages. It is incumbent upon medical providers and neurosurgeons in particular to be aware of the potential for mass casualty events and to make necessary preparations.

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Chris Schulz, Uwe Max Mauer, Renè Mathieu and Gregor Freude

OBJECTIVE

Since 2007, a continuous neurosurgery emergency service has been available in the International Security Assistance Force (ISAF) field hospital in Mazar-e-Sharif (MeS), Afghanistan. The object of this study was to assess the number and range of surgical procedures performed on the spine in the period from 2007 to 2014.

METHODS

This is a retrospective analysis of the annual neurosurgical caseload statistics from July 2007 to October 2014 (92 months). The distribution of surgical urgency (emergency, delayed urgency, or elective), patient origin (ISAF, Afghan National Army, or civilian population), and underlying causes of diseases and injuries (penetrating injury, blunt injury/fracture, or degenerative disease) was analyzed. The range and pattern of diagnoses in the neurosurgical outpatient department from 2012 and 2013 were also evaluated.

RESULTS

A total of 341 patients underwent neurosurgical operations in the period from July 2007 to October 2014. One hundred eighty-eight (55.1%) of the 341 procedures were performed on the spine, and the majority of these surgeries were performed for degenerative diseases (127/188; 67.6%). The proportion of spinal fractures and penetrating injuries (61/188; 32.4%) increased over the study period. These spinal trauma diagnoses accounted for 80% of the cases in which patients had to undergo operations within 12 hours of presentation (n = 70 cases). Spinal surgeries were performed as an emergency in 19.8% of cases, whereas 17.3% of surgeries had delayed urgency and 62.9% were elective procedures. Of the 1026 outpatient consultations documented, 82% were related to spinal issues.

CONCLUSIONS

Compared to the published numbers of cases from neurosurgery units in the rest of the ISAF area, the field hospital in MeS had a considerably lower number of operations. In addition, MeS had the highest rates of both elective neurosurgical operations and Afghan civilian patients. In comparison with the field hospital in MeS, none of the other ISAF field hospitals showed such a strong concentration of degenerative spinal conditions in their surgical spectrum. Nevertheless, the changing pattern of spine-related diagnoses and surgical therapies in the current conflict represents a challenge for future training and material planning in comparable missions.

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Masaaki Yamamoto, Yoshinori Higuchi, Toru Serizawa, Takuya Kawabe, Osamu Nagano, Yasunori Sato, Takao Koiso, Shinya Watanabe, Hitoshi Aiyama and Hidetoshi Kasuya

OBJECTIVE

The results of 3-stage Gamma Knife treatment (3-st-GK-Tx) for relatively large brain metastases have previously been reported for a series of patients in Chiba, Japan (referred to in this study as the C-series). In the current study, the authors reappraised, using a competing risk analysis, the efficacy and safety of 3-st-GK-Tx by comparing their experience with that of the C-series.

METHODS

This was a retrospective cohort study. Among 1767 patients undergoing GK radiosurgery for brain metastases at Mito Gamma House during the 2005–2015 period, 78 (34 female, 44 male; mean age 65 years, range 35–86 years) whose largest tumor was > 10 cm3, treated with 3-st-GK-Tx, were studied (referred to in this study as the M-series). The target volumes were covered with a 50% isodose gradient and irradiated with a peripheral dose of 10 Gy at each procedure. The interval between procedures was 2 weeks. Because competing risk analysis had not been employed in the published C-series, the authors reanalyzed the previously published data using this method.

RESULTS

The overall median survival time after 3-st-GK-Tx was 8.3 months (95% CI 5.6–12.0 months) in the M-series and 8.6 months (95% CI 5.5–10.6 months) in the C-series (p = 0.41). Actuarial survival rates at the 6th and 12th post–3-st-GK-Tx months were, respectively, 55.1% and 35.2% in the M-series and 62.5% and 26.4% in the C-series (HR 1.175, 95% CI 0.790–1.728, p = 0.42). Cumulative incidences at the 12th post–3-st-GK-Tx, determined by competing risk analyses, of neurological deterioration (14.2% in C-series vs 12.8% in M-series), neurological death (7.2% vs 7.7%), local recurrence (4.8% vs 6.2%), repeat SRS (25.9% vs 18.0%), and SRS-related complications (2.3% vs 5.1%) did not differ significantly between the 2 series.

CONCLUSIONS

There were no significant differences in post–3-st-GK-Tx results between the 2 series in terms of overall survival times, neurological death, maintained neurological status, local control, repeat SRS, and SRS-related complications. The previously published results (C-series) are considered to be validated by the M-series results.

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Lily H. Kim, Jennifer L. Quon, Felicia W. Sun, Kristen M. Wortman, Maheen M. Adamson and Odette A. Harris

The impact of traumatic brain injury (TBI) has been demonstrated in various studies with respect to prevalence, morbidity, and mortality data. Many of the patients burdened with long-term sequelae of TBI are veterans. Although fewer in number, female veterans with TBI have been suggested to suffer from unique physical, mental, and social challenges. However, there remains a significant knowledge gap in the sex differences in TBI. Increased female representation in the military heralds an increased risk of TBI for female soldiers, and medical professionals must be prepared to address the unique health challenges in the face of changing demographics among the veteran TBI population. In this review, the authors aimed to present the current understanding of sex differences in TBI in the veteran population and suggest directions for future investigations.

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M. Benjamin Larkin, Erin K. M. Graves, Jason H. Boulter, Nicholas S. Szuflita, R. Michael Meyer, Michael E. Porambo, John J. Delaney and Randy S. Bell

OBJECTIVE

There are limited data concerning the long-term functional outcomes of patients with penetrating brain injury. Reports from civilian cohorts are small because of the high reported mortality rates (as high as 90%). Data from military populations suggest a better prognosis for penetrating brain injury, but previous reports are hampered by analyses that exclude the point of injury. The purpose of this study was to provide a description of the long-term functional outcomes of those who sustain a combat-related penetrating brain injury (from the initial point of injury to 24 months afterward).

METHODS

This study is a retrospective review of cases of penetrating brain injury in patients who presented to the Role 3 Multinational Medical Unit at Kandahar Airfield, Afghanistan, from January 2010 to March 2013. The primary outcome of interest was Glasgow Outcome Scale (GOS) score at 6, 12, and 24 months from date of injury.

RESULTS

A total of 908 cases required neurosurgical consultation during the study period, and 80 of these cases involved US service members with penetrating brain injury. The mean admission Glasgow Coma Scale (GCS) score was 8.5 (SD 5.56), and the mean admission Injury Severity Score (ISS) was 26.6 (SD 10.2). The GOS score for the cohort trended toward improvement at each time point (3.6 at 6 months, 3.96 at 24 months, p > 0.05). In subgroup analysis, admission GCS score ≤ 5, gunshot wound as the injury mechanism, admission ISS ≥ 26, and brain herniation on admission CT head were all associated with worse GOS scores at all time points. Excluding those who died, functional improvement occurred regardless of admission GCS score (p < 0.05). The overall mortality rate for the cohort was 21%.

CONCLUSIONS

Good functional outcomes were achieved in this population of severe penetrating brain injury in those who survived their initial resuscitation. The mortality rate was lower than observed in civilian cohorts.

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Dong Liu, Yanhe Li, Yipei Zhang, Zhiyuan Zhang, Guoxiang Song and Desheng Xu

OBJECTIVE

This article is a preliminary evaluation of the efficacy of volume-staged Gamma Knife radiosurgery (GKRS) in the treatment of patients with orbital venous malformations (OVMs).

METHODS

Twenty patients with moderate to large OVMs were treated with volume-staged GKRS between March 2005 and October 2015. The series included 8 male and 12 female patients with an average age of 22.5 years (range 9–45 years). The diagnoses were confirmed intraoperatively and at pathological examination in 14 cases and presumed in accordance with clinical and imaging findings in 6 cases. The median OVM volume was 12.2 cm3 (range 7.1–34.6 cm3). The median interval between stages was 10 months (range 6–12 months). The tumor margin dose for each stage ranged from 11.0 to 13.5 Gy. The median duration of follow-up was 45.5 months (range 18–98 months).

RESULTS

Periodically scheduled MRI studies demonstrated evidence of a significant reduction of the original OVM volume in all cases. Visual acuity (VA) was preserved in 18 cases (90%). Five patients (25%) experienced vision improvement of varying degrees, and 13 (65%) experienced long-term preservation of VA at their pre-GKRS level. Deterioration in VA was observed in only 2 cases (10%). MRI demonstrated OVM regression after treatment in all cases, and all patients were found to have reduction of exophthalmos after volume-staged GKRS. Follow-up MRI revealed recurrence in only 1 case (5%). Three patients (15%) developed transient conjunctival edema.

CONCLUSIONS

This retrospective investigation indicates that volume-staged GKRS provides an effective management option in selected patients with OVMs, providing excellent visual outcomes. The study adds substantial support for volume-staged GKRS as a major treatment for OVMs.