Threat Appraisal, Recovery Operations, and PTSD Symptoms Among US Air Force Rescue Personnel

BACKGROUND

Research among military personnel and veterans indicates that subjective appraisal of warzone stressors explains the relation of combat exposure to posttraumatic stress disorder (PTSD), but not the relation of exposure to injury and death to PTSD. Studies have primarily been limited to conventional forces using aggregate measures of warzone stressor exposure. Threat appraisal may play a different role in the emergence of PTSD among military personnel for whom dangerous deployment experiences are more closely associated with exposure to injury and death, such as US Air Force Pararescuemen and Combat Rescue officers.

MATERIALS AND METHODS

In a sample of 207 rescue personnel, correlations among various types of warzone stressor exposure, threat appraisal, and postdeployment PTSD symptoms were examined.

RESULTS

The relative strongest correlates of threat appraisal were stressors related to injury, death, and human remains. Although exposure to these stressors was also correlated with PTSD symptom severity, partial correlations of stressor exposure and PTSD symptoms were no longer significant when adjusting for threat appraisal.

CONCLUSION

Results support the contributing role of threat appraisal to PTSD among military personnel whose primary duties entail exposure to injury and death under hostile and dangerous conditions.

Effectiveness of and Adherence to Triage Algorithms During Prehospital Response to Mass Casualty Incidents

Mass casualty incidents (MCIs) can rapidly exhaust available resources and demand the prioritization of medical response efforts and materials. Principles of triage (i.e., sorting) from the 18th century have evolved into a number of modern-day triage algorithms designed to systematically train responders managing these chaotic events. We reviewed reports and studies of MCIs to determine the use and efficacy of triage algorithms. Despite efforts to standardize MCI responses and improve the triage process, studies and recent experience demonstrate that these methods have limited accuracy and are infrequently used.

Commercial and Improvised Pelvic Compression Devices: Applied Force and Implications for Hemorrhage Control

Uncontrolled hemorrhage secondary to unstable pelvic fractures is a preventable cause of prehospital death in the military and civilian sectors. Because the mortality rate associated with unstable pelvic ring injuries exceeds 50%, the use of external compression devices for associated hemorrhage control is paramount. During mass casualty incidents and in austere settings, the need for multiple external compression devices may arise. In assessing the efficacy of these devices, the magnitude of applied force has been offered as a surrogate measure of pubic symphysis diastasis reduction and subsequent hemostasis. This study offers a sensor-circuit assessment of applied force for a convenience sample of pelvic compression devices. The SAM® (structural aluminum malleable) Pelvic Sling II (SAM Medical) and improvised compression devices, including a SAM Splint tightened by a Combat Application Tourniquet® (C-A-T; North American Rescue) and a SAM® Splint tightened by a cravat, as well as two joined cravats and a standard-issue military belt, were assessed in male and female subjects. As hypothesized, compressive forces applied to the pelvis did not vary significantly based on device operator, subject sex, and subject body fat percentage. The use of the military belt as an improvised method to obtain pelvic stabilization is not advised.

Prehospital Iliac Crest Intraosseous Whole Blood Infusion

Low-titer cold-stored O-positive whole blood (LTCSO+WB) resuscitation therapy is the cornerstone of military hemorrhagic shock resuscitation. During the past 19 years, improved patient outcomes have shown the importance of this intervention in shock treatment. Iliac crest intraosseous (IO) placement is an alternative when peripheral sites such as the humeral head and tibia are not available options. To date, no study has explored the administration of LTCSO+WB through an iliac crest IO in the military prehospital setting. Contingency procedures for vascular access are necessary for casualties with severe trauma to all four extremities, and the iliac crest is a viable option. The literature supports situational advantages over other peripheral IO sites.

23.4% Hypertonic Saline: A Tactical Option for the Management of Severe Traumatic Brain Injury With Impending or Ongoing Herniation

There are limited options available to the combat medic for management of traumatic brain injury (TBI) with impending or ongoing herniation. Current pararescue and Tactical Combat Casualty Care (TCCC) guidelines prescribe a bolus of 3% or 5% hypertonic saline. However, this fluid bears a tactical burden of weight (~570g) and pack volume (~500cm3). Thus, 23.4% hypertonic saline is an attractive option, because it has a lighter weight (80g) and pack volume (55cm3), and it provides a similar osmotic load per dose. Current literature supports the use of 23.4% hypertonic saline in the management of acute TBI, and evidence indicates that it is safe to administer via peripheral and intraosseous cannulas. Current combat medic TBI treatment algorithms should be updated to include the use of 23.4% hypertonic saline as an alternative to 3% and 5% solutions, given its effectiveness and tactical advantages.

Rationale and Implementation of a Novel Special Operations Medical Officer Course

BACKGROUND

The Air Force Special Warfare Medical Officer Course was created to address the lack of operationally focused, job-specific clinical training for medical officers (MOs). This course addresses the gap in knowledge, skill, and application of operational medicine, as well as the behavioral health, human performance, education, and medical oversight of Operators.

METHODS

The course was designed around the senior author's decade of experience piecing together training for his own role as a pararescue flight surgeon and informed by 5 years of flight surgeon courses, lessons learned from case studies of ill-prepared deployed physicians, and input from prehospital medicine subject matter experts.

RESULTS

Air Force pararescue and special tactics flight surgeons, physician assistants, and an independent duty medical technician (IDMT) attended. The course consisted of 10 full weekdays of didactics and skills sessions covering theory and application of operational medicine, human performance optimization, behavioral health for Operators, adult education theory, principles of prehospital clinical oversight, and other expeditionary concepts. The course culminated with combat casualty care scenario-based exercises, in which the providers performed operational medicine in full kit with weapons and simulation rounds.

DISCUSSION

For many logistical and practical reasons, civilian medical experience, traditional military medical training, existing special operations medical courses, and "merit badge" card classes are not adequate preparation for this specialized role. Focused, job-specific training should be provided to Special Operations Forces Medical Officers (SOFMO) and, ultimately, to any MO deploying in support of medics or combatants. The goal is to maximize the success of military medical operations while reducing the morbidity and mortality of combat and training casualties.

CONCLUSION

This operationally focused MO course can serve as a model for the future training of SOFMO and has stimulated discussion for consideration of a joint approach to prehospital medical training.

Ketamine Administration by Special Operations Medical Personnel During Training Mishaps

BACKGROUND

Opioids can have adverse effects on casualties in hemorrhagic shock. In 2014, the Committee on Tactical Combat Casualty Care (CoTCCC) recommended the use of ketamine at the point of injury (POI). Despite these recommendations the adherence is moderate at best. Poor use may stem from a lack of access to use ketamine during training. The United States Special Operations Command (USSOCOM) is often in a unique position, they maintain narcotics for use during all training events and operations. The goal of this work is to demonstrate that ketamine is safe and effective in both training and operational environments.

METHODS

This was a retrospective, observational performance improvement project within United States Special Operations Command and Air Combat Command that included the US Army's 75th Ranger Regiment, 160th Special Operations Aviation Regiment, and US Air Force Pararescue. Descriptive statistics were used to calculate the doses per administration to include the interquartile range (IQR), standard deviation (SD) and the range of likely doses using a 95% confidence interval (CI). A Wilcoxon signed-rank test was used to compare the mean pre-ketamine pain scores to the mean post-ketamine on a 0-to-10 pain scale.

RESULTS

From July 2010 to October 2017, there was a total of 34 patients; all were male. A total of 22 (64.7%) received intravenous ketamine and 12 (35.3%) received intramuscular ketamine and 8 (23.5%) received intranasal ketamine. The mean number of ketamine doses via all routes administered to patients was 1.88 (SD 1.094) and the mean total dose of all ketamine administration was 90.29mg (95% CI, 70.09-110.49). The mean initial dose of all ketamine administration was 47.35mg (95% CI, 38.52-56.18). The median preketamine pain scale for casualties was noted to be 8.0 (IQR 3) and the median post-ketamine pain scale was 0.0 (IQR 3).

CONCLUSION

Ketamine appears to be safe and effective for use during military training accidents. Military units should consider allowing their medics to carry and use as needed.

A Case Series of Air Force Pararescue Long-Range Ocean Rescues

BACKGROUND

US Air Force (USAF) pararescuemen (PJs) perform long-range ocean rescue missions for ill or injured civilians when advanced care and transport are not available. The purpose of this case series is to examine the details of these missions, review patient treatments and outcomes, and describe common tactics, techniques, and procedures for these missions.

METHODS

Cases in which the USAF PJs preformed long-range ocean rescue for critically ill or injured civilians between 2011 and 2018 were identified. Case information was obtained, including patient demographics, location, infiltration/exfiltration methods, diagnoses, treatments, duration of patient care, patient outcome, and lessons learned.

RESULTS

A total of 14 pararescue missions involving 22 civilians were identified for analysis. Of the 22 patients, 10 (45%) suffered burns, six (27%) had abdominal issues, four (18%) had musculoskeletal injuries, one had a traumatic brain injury, and one had a necrotizing soft-tissue infection. Medical care of these patients included intravenous fluid and blood product resuscitation, antibiotics, analgesics, airway management, and escharotomy. The median duration of patient care was 51 hours.

CONCLUSION

This case series illustrates the complex transportation requirements, patient and gear logistical challenges, austere medicine, and prolonged field care (PFC) unique to USAF PJ open-water response.

Management of Critically Injured Burn Patients During an Open Ocean Parachute Rescue Mission

Best practices and training for prolonged field care (PFC) are evolving. The New York Pararescue Team has used part task training, cadaver labs, clinical rotations, and a complicated sim lab to prepare for PFC missions including critical care. This report details an Atlantic Ocean nighttime parachute insertion to provide advanced burn care to two sailors with 50% and 60% body surface area burns. Medical mission planning included pack-out of ventilators, video laryngoscopes, medications, and 50 L of lactated Ringer's (LR). Over the course of 37 hours, the patients required high-volume resuscitation, analgesia, wound care, escharotomies, advanced airway and ventilator management, continuous sedation, telemedicine consultation, and complicated patient movement during evacuation. A debrief survey was obtained from the Operators highlighting recommendation for more clinical rotations and labs, missionspecific pack-outs, and tactical adjustments. This historic mission represents the most sophisticated PFC ever performed by PJs and serves to validate and share our approach to PFC.

Efficacy of the Mnemonic Device "MARCH PAWS" as a Checklist for Pararescuemen During Tactical Field Care and Tactical Evacuation

BACKGROUND

The application of Tactical Combat Casualty Care (TCCC) represents evidence-based medicine to improve survival in combat. Over the past several years, US Air Force Pararescuemen (PJs) have expanded the mnemonic device "MARCH" to "MARCH PAWS" for use during tactical field care and tactical evacuation (TACEVAC). The mnemonic stands for massive bleeding, airway, respiration, circulation, head and hypothermia, pain, antibiotics, wounds, and splinting. We undertook this performance improvement project to determine the efficacy of this device as a treatment checklist.

METHODS

The mission reports of a 16-PJ combat rescue deployment to Operation Enduring Freedom (OEF) from January through June 2012 were reviewed. The triage category, mechanism of injury, injury, and treatments were noted. The treatments were then categorized to determine if they were included in MARCH PAWS.

RESULTS

The recorded data for missions involving 465 patients show that 45%, 48%, and 7%, were in category A, B, and C, respectively (urgent, priority, routine); 55% were battle injuries (BIs) and 45% were nonbattle injuries (NBIs). All treatments for BI were accounted for in MARCH PAWS. Only 9 patients' treatments with NBI were not in MARCH PAWS.

CONCLUSION

This simple mnemonic device is a reliable checklist for PJs, corpsmen, and medics to perform TACEVAC during combat Operations, as well as care for noncombat trauma patients.

The Role of Magnetic Resonance Imaging in Optimizing Injury Management in Air Force Pararescuemen, Combat Rescue Officers, and Survival Specialists

Operators perform physically demanding jobs associated with a variety of overuse and acute musculoskeletal injuries. The current management of musculoskeletal complaints in the Air Force includes plane radiographs and 6 weeks of physical therapy (PT) before consideration of orthopedic consultation and magnetic resonance imaging (MRI); however, MRI shows a clear advantage compared with plane radiographs. We conducted a performance improvement project and conclude that (1) MRI allowed for definitive diagnosis as well as definitive triage for care in a timely manner, (2) guidelines for ordering lumbosacral MRIs should be followed and not ordered for pain that is not progressive and severe or not associated with a neurological finding, and (3) because of the risk of X-ray exposure in patients in their 20 and 30s, X-rays should be avoided in this setting unless definitely indicated.

Optimization of Simulation and Moulage in Military-Related Medical Training

Preparation of Special Operations Forces (SOF) Medics as first responders for the battle space and austere environments is critical to optimize survival and quality of life for our Operators who may sustain serious and complex wounding patterns and illnesses. In the absence of constant clinical exposure for these medics, it is necessary to maximize all available training opportunities. The incorporation of scenario-based training helps weave together teamwork and the ability to practice treatment protocols in a tactical, controlled training environment to reproduce, to some degree, the environment in and stressors under which care will need to be delivered. We reviewed the evolution of training scenarios within one Pararescue (PJ) team since 2008 and codified various tools used to simulate physical findings and drive medical exercises as part of scenario-based training. We also surveyed other SOF Medic training resources.

Review of 54 Cases of Prolonged Field Care

BACKGROUND

Prolonged field care (PFC) is field medical care applied beyond doctrinal planning time-lines. As current and future medical operations must include deliberate and contingency planning for such events, data are lacking to support efforts. A case review was conducted to define the epidemiology, environment, and operational factors that affect PFC outcomes.

METHODS

A survey distributed to US military medical providers solicited details of PFC encounters lasting more than 4 hours and included patient demographics, environmental descriptors, provider training, modes of transportation, injuries, mechanism of injury, vital signs, treatments, equipment and resources used, duration of PFC, and morbidity and mortality status on delivery to the next level of care. Descriptive statistics were used to analyze survey responses.

RESULTS

Surveys from 54 patients treated during 41 missions were analyzed. The PFC provider was on scene at time of injury or illness for 40.7% (22/54) of cases. The environment was described as remote or austere for 96.3% (52/54) of cases. Enemy activity or weather also contributed to need for PFC in 37.0% (20/54) of cases. Care was provided primarily outdoors (37.0%; 20/54) and in hardened nonmedical structures (37.0%; 20/54) with 42.6% (23/54) of cases managed in two or more locations or transport platforms. Teleconsultation was obtained in 14.8% (8/54) of cases. The prehospital time of care ranged from 4 to 120 hours (median 10 hours), and five (9.3%) patients died prior to transport to next level of care.

CONCLUSION

PFC in the prehospital setting is a vital area of military medicine about which data are sparse. This review was a novel initial analysis of recent US military PFC experiences, with descriptive findings that should prove helpful for future efforts to include defining unique skillsets and capabilities needed to effectively respond to a variety of PFC contingencies.

Preliminary Comparison of New and Established Tactical Tourniquets in a Manikin Hemorrhage Model

BACKGROUND

Emergency tourniquet use has been associated with hemorrhage control and improved survival during the wars since 2001. The purpose of the present study is to compare the differential performance of two new tactical tourniquets with the standard-issue tourniquet to provide preliminary evidence to guide decisions on device development.

METHODS

A laboratory experiment was designed to test the effectiveness of tourniquets on a manikin thigh. Three models of tourniquets were assessed. The Rapid Application Tourniquet System (RATS) and the Tactical Mechanical Tourniquet (TMT) were compared with the standard-issue Combat Application Tourniquet(®) (C-A-T). Two users conducted 30 tests each.

RESULTS

Percentages for effectiveness (hemorrhage control, yes/no) and distal pulse cessation did not differ significantly by model. When compared with the RATS, the C-A-T performed better (ρ < .001) for time to hemorrhage control and fluid loss. The C-A-T and TMT had comparable responses for most measures, but the C-A-T applied more pressure (ρ = .04) than did the TMT for hemorrhage control.

CONCLUSION

All three tactical tourniquets showed substantial capacity for hemorrhage control. However, the two new tourniquet models (RATS and TMT) did not offer any improvement over the C-A-T, which is currently issued to military services. Indeed, one of the new models, the RATS, was inferior to the C-A-T in terms of speed of application and simulated loss of blood. Opportunities were detected for refinements in design of the two new tourniquets that may offer future improvements in their performance.

Cinnarizine for Sea Sickness During a Remote Pacific Ocean Rescue Mission

Motion sickness can be a limiting factor for sea and air missions. We report the experience of a Pararescue (PJ) team on a Pacific Ocean rescue mission in which motion sickness was prevalent. Cinnarizine, an antagonist of H1-histamine receptors, was used to treat affected PJs. We also report findings of a survey of PJs regarding motion sickness. A family of four on a disabled sailboat 900 miles off the coast of Mexico sent out a distress call because their 1-year-old daughter became severely ill with fever and diarrhea. Four PJs were deployed on a C-130, performed a free-fall parachute insertion into the ocean, and boarded the sailboat. All four PJs experienced onset of motion sickness at some point during the early part of the mission and symptoms persisted through the first 24 hours. Three PJs experienced ongoing nausea, vomiting, dizziness, and sensory imbalances. The captain of the sailboat offered the three sick PJs approximately 18mg of cinnarizine two or three times a day with relief of symptoms and improvement on operational effectiveness. A new, anonymous, voluntary survey of Air National Guard PJs and combat rescue officers revealed that 78.4% of Operators have experienced motion sickness at sea. We discuss the current theories on motion sickness, the effect of motion sickness on operational effectiveness, and research on treatment of motion sickness, including the medication cinnarizine.

Pilot ejection, parachute, and helicopter crash injuries

USAF Pararescuemen (PJs) respond to downed aircrew as a fundamental mission for personnel recovery (PR), one of the Air Force's core functions. In addition to responding to these in Military settings, the PJs from the 212 Rescue Squadron routinely respond to small plane crashes in remote regions of Alaska. While there is a paucity of information on the latter, there have been articles detailing injuries sustained from helicopter crashes and while ejecting or parachuting from fixed wing aircraft. The following represents a new chapter added to the Pararescue Medical Operations Handbook, Sixth Edition (2014, editors Matt Wolf, MD, and Stephen Rush, MD, in press). It was designed to be a quick reference for PJs and their Special Operations flight surgeons to help with understanding of mechanism of injury with regard to pilot ejection, parachute, and helicopter accident injuries. It outlines the nature of the injuries sustained in such mishaps and provides an epidemiologic framework from which to approach the problem.

Recent consideration in tactical medicine

A philosophical approach to tactical and remote medicine should be reflected in the gear (e.g., equipment and technology) chosen as well as the protocols used. The gear needs to be lightweight and small volume. Asmuch as possible, it should have multiple uses, and there should be no redundancy with other items. When modern technology (e.g., hemostatic gauze, pulse oximeters, etc.) allows it to have unique applications, it should be used. Otherwise, if simple basic gear works, it should remain a staple (e.g., cravats). Protocols should reflect the goal to provide thorough care in an efficient manner. They should be straightforward and scaleable and be capable of being trained in a fashion that will allow them to become automatic under duress. These guiding principles establish a basis from which the Special Operations Forces/Tactical Medic or PJ can operate to maximal effectiveness. This article will describe current thinking in Pararescue as it relates to gear and protocols.

Long-term Outcomes After Staged-Volume Stereotactic Radiosurgery for Large Arteriovenous Malformations

BACKGROUND:

Stereotactic radiosurgery is an effective treatment modality for small arteriovenous malformations (AVMs) of the brain. For larger AVMs, the treatment dose is often lowered to reduce potential complications, but this decreases the likelihood of cure. One strategy is to divide large AVMs into smaller anatomic volumes and treat each volume separately.

OBJECTIVE:

To prospectively assess the long-term efficacy and complications associated with staged-volume radiosurgical treatment of large, symptomatic AVMs.

METHODS:

Eighteen patients with AVMs larger than 15 mL underwent prospective staged-volume radiosurgery over a 13-year period. The median AVM volume was 22.9 mL (range, 15.7-50 mL). Separate anatomic volumes were irradiated at 3- to 9-month intervals (median volume, 10.9 mL; range, 5.3-13.4 mL; median marginal dose, 15 Gy; range, 15-17 Gy). The AVM was divided into 2 volumes in 10 patients, 3 volumes in 5 patients, and 4 volumes in 3 patients. Seven patients underwent retreatment for residual disease.

RESULTS:

Actuarial rates of complete angiographic occlusion were 29% and 89% at 5 and 10 years. Five patients (27.8%) had a hemorrhage after radiosurgery. Kaplan-Meier analysis of cumulative hemorrhage rates after treatment were 12%, 18%, 31%, and 31% at 2, 3, 5, and 10 years, respectively. One patient died after a hemorrhage (5.6%).

CONCLUSION:

Staged-volume radiosurgery for AVMs larger than 15 mL is a viable treatment strategy. The long-term occlusion rate is high, whereas the radiation-related complication rate is low. Hemorrhage during the lag period remains the greatest source of morbidity and mortality.

Local control of newly diagnosed and distally recurrent, low-volume brain metastases with fixed-dose (20 gy) gamma knife radiosurgery

BACKGROUND

Metastases to the brain occur in 20% to 30% of patients with cancer and have been identified on autopsy in as many as 50% of patients.

OBJECTIVE

To analyze the efficacy of 20-Gy Gamma Knife radiosurgery (GKR) as initial treatment in patients with 1 to 3 brain metastases ≤ 2 cm in greatest diameter.

METHODS

A retrospective analysis of 114 consecutive adults with Karnofsky performance status ≥ 60 who received GKR for 1 to 3 brain metastases ≤ 2 cm in size was performed. Five patients lacked detailed follow-up and were excluded, leaving 109 for outcome analysis (34 men and 75 women; median age, 61.2 years). All metastases received 20 Gy to the 50% isodose line.

RESULTS

One hundred nine patients underwent treatment of 164 metastases at initial GKR. Twenty-six patients (23.9%) were alive at last follow-up (median time, 29.9 months; range, 6.6 months to 7.8 years). The median overall survival was 13.8 months (range, 1 day to 7.6 years). Among the 52 patients with distant failure, 33 patients received 20 Gy to 95 new lesions. A total of 259 metastases received 20 Gy, and 4 patients lacked imaging follow-up secondary to death before posttreatment imaging. Local failure occurred in 17 of 255 treated lesions (6.7%), yielding an overall local control rate of 93.3%. Actuarial local control at 6, 12, 24, and 36 months was 96%, 93%, 89%, and 88%, respectively. Permanent neurological complications occurred in 3 patients (2.8%).

CONCLUSION

Among patients with 1 to 3 brain metastases ≤ 2 cm in size who have not received whole-brain radiation therapy, GKR with 20 Gy provides high rates of local control with low morbidity and excellent neurological symptom-free survival.

A Magnetic Resonance Imaging Study to Define Optimal Needle Length for Humeral Head IO Devices

INTRODUCTION

Intraosseous (IO) devices have gained popularity because of TCCC. The ability to gain access to the vascular system when intra venous access is not possible, and techniques such as central lines or cut-downs are beyond the scope of battlefield providers and tactically not feasible, has lead to the increased use of IO access. Since tibias are often not available sites in blast injury patients, the sternum was often used. Recently the humeral head has gained popularity because of ease of access and placement. The optimal needle length has not been defined or studied.

METHODS AND MATERIALS

Fifty consecutive shoulder MRIs among 18?40 year old patients were reviewed. Distances from the skin surface to the cortex from anterior and lateral trajectories were simulated and measured. Two different lateral trajectories were studied described as lateral minimum and lateral maximum trajectories, correlating with seemingly less and greater soft tissue. The cortical thickness was also recorded. Mean values and ranges for the measurements were determined.

RESULTS

The anterior trajectory represented the shortest distance. Mean anterior, mean lateral minimum and mean lateral maximum distances were 2.3, 3.0 and 4.7cm with corresponding ranges of 1.1?4.1, 1.6?5.7 and 2.8?7.4cm respectively. The cortical thickness was 4mm in all cases.

CONCLUSIONS

Although this information was gathered amongst civilians, and many military members may have more soft tissue, these results indicate that needle length generally in the 40?50mm range should be used via the anterior approach. Use of a standard 25mm needle often used in the tibia would be inadequate in over half the cases, and may result in undue tissue compression or distortion.

Tactical physical preparation: the case for a movement-based approach

Progressive injury prevention and physical preparation programs are needed in military special operations to optimize mission success and Operator quality of life and longevity. While physical risk is inherent in Special Operations, non-traumatic injuries resulting from overuse, poor biomechanics, and arbitrary exercise selection can be alleviated with proper medical care and patient education. An integrated approach to physical readiness that recognizes the continuity between rehabilitation and performance training is advocated to ensure that physiological adaptations do not come at the expense of orthopedic health or movement proficiency. Movement quality should be regularly evaluated and enforced throughout the training process to minimize preventable injuries and avoid undermining previous rehabilitative care. While fitness and proper movement are not substitutes for Operator specific tasks, they are foundational to many tactically-relevant skills. In light of how much is at stake, sports medicine care in the military, especially special operations, should parallel that which is practiced in professional and collegiate athletics.

Efficacy of gamma knife radiosurgery for small-volume recurrent malignant gliomas after initial radical resection

OBJECTIVE

To review the authors' experience with Gamma Knife radiosurgery (GKR) for small recurrent high-grade gliomas (HGGs) following prior radical resection, external-beam radiation therapy (EBRT), and chemotherapy with temozolomide (TMZ).

METHODS

The authors retrospectively analyzed 26 consecutive adults (9 women and 17 men; median age 60.4 years; Karnofsky Performance Status [KPS]≥70) who underwent GKR for recurrent HGGs from 2004-2009. Median lesion volume was 1.22 cc, and median treatment dose was 15 Gy. Pathology included glioblastoma multiforme (GBM; n=16), anaplastic astrocytoma (AA; n=5), and anaplastic mixed oligoastrocytoma (AMOA; n=5). Two patients lost to follow-up were excluded from radiographic outcome analyses.

RESULTS

Median overall survival (OS) for the entire cohort from the time of GKR was 13.5 months. Values for 12-month actuarial survival from time of GKR for GBM, AMOA, and AA were 37%, 20% and 80%. Local failure occurred in 9 patients (37.5%) at a median time of 5.8 months, and 18 patients (75%) experienced distant progression at a median of 4.8 months. Complications included radiation necrosis in two patients and transient worsening of hemiparesis in one patient. Multivariate hazard ratio (HR) analysis showed KPS 90 or greater, smaller tumor volumes, and increased time to recurrence after resection to be associated with longer OS following GKR.

CONCLUSIONS

GKR provided good local tumor control in this group of clinically stable and predominantly high-functioning patients with small recurrent HGGs after radical resection. Meaningful survival times after GKR were seen. GKR can be considered for selected patients with recurrent HGGs.

Results of Surgical Resection for Progression of Brain Metastases Previously Treatedby Gamma Knife Radiosurgery

OBJECTIVE

To determine treatment outcome after surgical resection for progressive brain metastases after gamma knife radiosurgery (GKR) and to explore the role of dynamic contrast agent-enhanced perfusion magnetic resonance imaging (MRI) and proton spectroscopic MRI studies (MRS/P) in predicting pathological findings.

METHODS

Between 1997 and 2002, 32 patients underwent surgical resection for suspected progression of brain metastases from a cohort of 245 patients with brain metastases treated with GKR. Postradiosurgery MRI surveillance was performed at 6 and 12 weeks, and then every 12 weeks after GKR. In some cases, additional MRI scanning with spectroscopy or perfusion (MRS/P) was used to aid differentiation of radiation change from tumor progression. The decision to perform neurosurgical resection was based on MRI or clinical evidence of lesion progression among patients with a Karnofsky performance score of 60 or more and absent or stable systemic disease.

RESULTS

Thirteen percent (32 out of 245) of patients and 6% (38 out of 611) of lesions required surgical resection after GKR. The median time from GKR to surgical resection was 8.6 months (range, 1.7-27.1 mo). The 6-, 12-, and 24-month actuarial survival from time of GKR was 97, 78, and 47% for the resected patients and 65, 40, and 19% for the nonresected patients (P < 0.0001). The two-year survival rate of patients requiring two resections after GKR was 100% compared with 39% for patients undergoing one resection (P = 0.02). The median survival of resected patients was 27.2 months (range, 7.0-72.5 mo) from the diagnosis of brain metastases, 19.9 months (range, 5.0-60.7 mo) from GKR, and 8.9 months (range, 0.2-53.1 mo) from surgical resection. Tumor was found in 90% of resected specimens and necrosis alone in 10%. MRS/P studies were performed in 15 resected patients. Overall, MRS/P predicted tumor in 11 lesions, confirmed pathologically in nine lesions, and necrosis alone was found in two. The MRS/P predicted necrosis alone in three, whereas pathology revealed viable tumor in two and necrosis in one lesion.

CONCLUSION

Surgical intervention of progressive brain metastases after GKR in selected patients leads to a meaningful improvement in survival rates. Further studies are necessary to determine the role of MRS/P in the postradiosurgery surveillance of brain metastases.

Importance of MR technique for stereotactic radiosurgery

We investigated how frequently the imaging procedure we use immediately prior to radiosurgery--triple-dose gadolinium-enhanced MR performed with the patient immobilized in a nonrelocatable head frame and 1-mm-thick MPRAGE (magnetization-prepared rapid gradient echo) images (SRS3xGado)-identifies previously unrecognized cerebral metastases in patients initially imaged by conventional MR with single-dose gadolinium (1xGado). Between July 1998 and July 2000, the diagnoses established for 47 patients who underwent radio-surgical procedures for treatment of cerebral metastases at The Gamma Knife Center of New York University were based initially on the 1xGado protocol. In July 1998, we began using SRS3xGado as our routine imaging protocol in preparation for targeting lesions for radio-surgery, using triple-dose gadolinium and acquisition of contiguous 1-mm Tl-weighted axial images. Because our SRS3xGado scans sometimes unexpectedly revealed additional metastases, we sought to learn how frequently the initial 1xGado scans would underestimate the number of metastases. We therefore reviewed the number of brain metastases identified on the SRS3xGado studies and compared the results to the number found by the 1xGado protocol, which had initially identified the brain metastases. Additional metastases, ranging from 1 to 23 lesions per patient, were identified on the SRS3xGado scan in 23 of 47 patients (49%). In 57% of the 23 patients, only one additional lesion was identified. The mean time interval between the 1xGado and the SRS3xGado scans was 20.6 days (range, 4-83 days), and the number of additional lesions detected and the time interval between two scans were negatively correlated (-0.11). The number of lesions detected on the SRS3xGado was associated only with the number of lesions on the 1xGado and not with any other patient or tumor pretreatment characteristics such as age, gender, largest tumor volume on the 1xGado, or number of days between the 1xGado and the SRS3xGado or prior surgery. The identification of additional lesions with SRS3xGado MR may have implications for patients who are treated with stereotactic radiosurgery alone (without whole-brain irradiation) with single-dose gadolinium imaging, in that unidentified lesions may go untreated. As a result of these findings we continue to use and advocate SRS3xGado scans for radiosurgery.

Neuro-ophthalmological assessment of vision before and after radiation therapy alone for pituitary macroadenomas

Between 1972 and 1988, 25 patients were treated by radiation therapy (RT) alone for pituitary macroadenomas causing visual impairment. Twenty-three patients were evaluated by a neuro-ophthalmologist before treatment and at the time of follow-up review. Radiation treatment consisted of 4000 to 5000 cGy over 4 to 5 weeks. The median follow-up period was 36 months (range 2 to 192 months). Eighteen patients (78%) experienced visual field improvement. Deterioration occurred in four patients due to tumor recurrence, tumor hemorrhage, possible optic nerve necrosis, and optic chiasm herniation. Visual field improvement occurred predominantly in patients whose pretreatment visual field defects were less than a dense hemianopsia, who did not have diffuse optic atrophy, and who were younger than the median age of 69 years (p less than 0.001). Visual acuity improvement occurred in patients without diffuse optic atrophy, with only mild impairment of the visual acuity, and with only mild visual field loss prior to RT (p less than 0.002). It is concluded that there is a subset of patients with pituitary macroadenomas and visual impairment for whom primary RT is a treatment option.

Pituitary adenoma: the efficacy of radiotherapy as the sole treatment

The management of patients with pituitary adenomas by radiotherapy alone, using modern techniques of evaluation and current standards of treatment, has not been examined. This is a retrospective review of 29 such patients with nonfunctional or prolactin secreting pituitary macroadenomas. Patients were analyzed by visual fields, hormone levels, and CT scans. All but one patient received a tumor dose of 4500 cGy in 4 to 5 weeks. The tumor was controlled in 26 of 28 (93%) patients for an observed period of 3 to 14 years. Seventeen of 21 (81%) patients with visual impairment experienced normalization or improvement, and seven of ten (70%) patients with hyperprolactinemia achieved normalization of their serum prolactin levels. Post-treatment CT scanning revealed persistent tumor in nine of 17 patients despite clinical improvement. We conclude that: (a) radiotherapy is an effective treatment for these tumors; (b) doses need not exceed 4500 cGy in 25 fractions; (c) radiation is effective for improving vision; (d) radiation can normalize hyperprolactinemia; and (e) tumor regression is variable and unrelated to observed symptom regression.