Total Ankle Replacement in a Military Jet Pilot.

INTRODUCTION: A total ankle replacement in a jet pilot after an open, high-energy foot and ankle fracture and dislocation with talar extrusion in a plane crash was carefully evaluated before considering fitness to fly.CASE REPORT: A 33-yr-old male test pilot of the Italian Air Force was involved in a plane crash and reported an open high-energy fracture/dislocation of the right ankle, with the expulsion of the right talus due to the impact, and other fractures. A titanium replica was inserted inside the ankle. However, the patient suffered from intolerable pain and developed arthritic changes in the cartilage of the tibial plafond. For these reasons, a decision was made to perform a custom-made total ankle replacement.DISCUSSION: The 2-yr follow-up after the last operation and the evaluation of the pilot's fitness to fly are reported in this case study. The pilot was assessed fit to fly, including high performance military aircrafts.Verde P, Guardigli S, Morgagni F, Roberts S, Monopoli D, Scala A. Total ankle replacement in a military jet pilot. Aerosp Med Hum Perform. 2020; 91(7):597-603.

Effects of Hypobaric Hypoxia on Endothelial Function and Adiponectin Levels in Airforce Aviators.

Background: Hypobaric hypoxia (HH) increases the risk of high altitude-related illnesses (HARI). The pathophysiological mechanism(s) involved are still partially unknown. Altered vascular reactivity as consequence of endothelial dysfunction during HH might play a role in this phenomenon. Adiponectin exerts protective effect on cardiovascular system since it modulates NO release, antagonizing endothelial dysfunction. Aims of this study, performed in a selected population of airforce aviators, were (1) to investigate whether exposure to acute HH might be associated with endothelial dysfunction and (2) to evaluate whether adiponectin might be involved in modulating this phenomenon. Methods: Twenty aviators were exposed to acute HH in a hypobaric chamber by simulating altitude of 8000 and then 6000 m for 2 hours. Vascular reactivity was evaluated by the EndoPAT test immediately before and after the HH; salivary and blood adiponectin levels were measured. Results: EndoPAT performed immediately after HH divided pilots in two groups: 12 pilots with preserved vascular reactivity and 8 pilots with reduction of vascular reactivity, indicating that HH exposure might cause endothelial dysfunction. Salivary and blood adiponectin levels increased post-HH in a time-dependent manner in all aviators, but the significant increase was observed only in those with preserved vascular reactivity suggesting that HH stimulated release of adiponectin that, in turn, by exerting a protective effect, might reduce endothelial dysfunction. Conclusions: Acute HH may cause endothelial dysfunction due, at least in part, to reduced release of adiponectin. This phenomenon might be involved in pathophysiology of HARI.

Neck pain in F-16 vs. Typhoon fighter pilots.

INTRODUCTION: In jet pilots, the neck is stressed by dynamic loading and there is growing concern about possible neck damage in pilots of new agile aircraft. Jet pilots often report neck pain after flight so intense that their operational capability may be affected. However, there is no clear evidence of structural damage related to the operational exposure. METHODS: We compared 35 F-16 pilots with 35 age-matched Eurofighter Typhoon pilots. All subjects completed an anonymous questionnaire on their flight activity and neck pain. RESULTS: The incidence of neck pain in the F-16 group was 48.6% compared with 5.7% of the Typhoon group, significantly higher. In F-16 pilots, there was a significant association between neck pain and age over 30 yr, total flight hours, and flight hours exceeding 600. DISCUSSION: Our findings suggest that the risk of neck pain after flight is higher among F-16 pilots compared with Typhoon pilots. This could be due to several reasons, including the backward reclined seat of the F-16, which exposes the neck to the load in an unfavorable posture while moving the head during maneuvers at sustained high-G.

Gender differences in navigational memory: pilots vs. nonpilots.

INTRODUCTION: The coding of space as near and far is not only determined by arm-reaching distance, but is also dependent on how the brain represents the extension of the body space. Recent reports suggest that the dissociation between reaching and navigational space is not limited to perception and action but also involves memory systems. It has been reported that gender differences emerged only in adverse learning conditions that required strong spatial ability. METHODS: In this study we investigated navigational versus reaching memory in air force pilots and a control group without flight experience. We took into account temporal duration (working memory and long-term memory) and focused on working memory, which is considered critical in the gender differences literature. RESULTS: We found no gender effects or flight hour effects in pilots but observed gender effects in working memory (but not in learning and delayed recall) in the nonpilot population (Women's mean = 5.33; SD= 0.90; Men's mean = 5.54; SD= 0.90). We also observed a difference between pilots and nonpilots in the maintenance of on-line reaching information: pilots (mean = 5.85; SD=0.76) were more efficient than nonpilots (mean = 5.21; SD=0.83) and managed this type of information similarly to that concerning navigational space. In the navigational learning phase they also showed better navigational memory (mean = 137.83; SD=5.81) than nonpilots (mean = 126.96; SD=15.81) and were significantly more proficient than the latter group. DISCUSSION: There is no gender difference in a population of pilots in terms of navigational abilities, while it emerges in a control group without flight experience. We found also that pilots performed better than nonpilots. This study suggests that once selected, male and female pilots do not differ from each other in visuo-spatial abilities and spatial navigation.

Deficits in visuo-spatial but not in topographical memory during pregnancy and the postpartum state in an expert military pilot: a case report.

BACKGROUND: It is well known that cognitive and emotional changes occur during pregnancy, but little is known about their magnitude or their time of occurrence and recovery. During pregnancy memory is one of the most impaired cognitive functions. Although long-term aspects of memory have been investigated, other aspects of memory have not yet been explored (i.e., navigational memory and reaching memory). CASE PRESENTATION: Here we describe the changes in reaching and walking memory that occurred during pregnancy and one year after delivery in an Italian female military pilot (Case 1) with high spatial ability. In memory tests she showed a classical dissociation between performance in reaching and walking distance, which indicated a failure of working memory, learning, and storage in reaching space. This suggests that her expertise served as a protective factor mitigating her low walking memory performance, and saving the topographical component.We compared her performance with that of two non-pregnant control groups (i.e., women pilots and non-pilots) and found that Case 1's reaching memory performance was significantly worse than that of the control groups. Even one year postpartum, Case 1's performance was not yet the same as that of the other pilots. CONCLUSIONS: These findings contribute to our knowledge of the specific, as yet unexplored, aspects of memory deficits in women pilots during pregnancy and postpartum and suggest the need for better neuropsychological assessment before these women return to work in operational environments.

Visual function at altitude under night vision assisted conditions.

INTRODUCTION: Hypoxia, even mild, is known to produce negative effects on visual function, including decreased visual acuity and sensitivity to contrast, mostly in low light. This is of special concern when night vision devices (NVDs) are used during flight because they also provide poor images in terms of resolution and contrast. METHODS: While wearing NVDs in low light conditions, 16 healthy male aviators were exposed to a simulated altitude of 12,500 ft in a hypobaric chamber. RESULTS: Snellen visual acuity decreased in normal light from 28.5 +/- 4.2/20 (normoxia) to 37.2 +/- 7.4/20 (hypoxia) and, in low light, from 33.8 +/- 6.1/20 (normoxia) to 42.2 +/- 8.4/20 (hypoxia), both at a significant level. An association was found between blood oxygen saturation and visual acuity without significance. No changes occurred in terms of sensitivity to contrast. DISCUSSION: Our data demonstrate that mild hypoxia is capable of affecting visual acuity and the photopic/high mesopic range of NVD-aided vision. This may be due to several reasons, including the sensitivity to hypoxia of photoreceptors and other retinal cells. Contrast sensitivity is possibly preserved under NVD-aided vision due to its dependency on the goggles' gain.

Mental rotation task in a pilot during and after pregnancy.

INTRODUCTION: Discordant findings have been reported about the change in pregnant women's cognitive test performance. Visuo-spatial abilities, which are crucial in terrestrial/flight navigation, could be influenced by hormonal variations. CASE REPORT: A 32-yr-old Italian Air Force pilot underwent a 2-D Mental Rotation Task (MRT) and hormonal assessment in the second trimester of pregnancy and 1 yr after delivery. Her performance was compared with that of two nonpregnant groups of women: one with flying experience and the other without. Estradiol and progesterone were significantly higher in pregnancy compared with postpartum, while testosterone was almost unchanged. During pregnancy, we observed a significant difference in the subject's response time compared with pilots (she was slower) and nonpilots (she was faster). One year after delivery, her performance was still better than the nonpilot group and was almost the same as the pilot group. DISCUSSION: Our data are consistent with an effect of pregnancy on visuo-spatial ability that can last for some time after delivery, even with the early recovery of the hormonal levels. MRT smoothly changed in our subject, supporting previous findings that women who are experts in flight navigation are less sensitive to hormonal fluctuations. CONCLUSION: In this case, visuospatial ability requiring effortful processing underwent variations during pregnancy and postpartum. Further studies are needed in order to confirm our observations in a wider population.

Bilateral chemodectoma: medicolegal considerations on a case report of aeromedical concern.

The authors describe a case of bilateral carotid chemodectoma occurring in a military pilot who was assessed and evaluated in terms of aeromedical and medico-legal aspects for his fitness to fly. In view of the lack of specific guidelines and/or regulations, both national and international, we choose to follow a multidisciplinary clinical approach that included aero-physiological tests in the hypobaric chamber, in order to identify a standard protocol that could be used as reference for similar future cases, where this kind of assessment is necessary.

Predictors of ear barotrauma in aircrews exposed to simulated high altitude.

INTRODUCTION: Ear barotrauma is an adverse effect related to hypobaric exposure. Ear, nose, and throat (ENT) diseases are risk factors for barotrauma in aircrews trained in a hypobaric chamber, but excluding affected subjects from exposure does not abolish the risk in asymptomatic trainees. We investigated other possible predictors, including history of ENT diseases, ENT clinical abnormalities, altitude, and subject's age. METHODS: After a complete ENT evaluation including otoscopy and tympanometry, 314 aircrews underwent hypobaric chamber training. Two altitude training profiles up to 35,000 ft (10,668 m) and 25,000 ft (7620 m), respectively, were used. Subjects were grouped according to if they were asymptomatic, had acute barotitis, or reported delayed ear pain the day after the exposure. RESULTS: There were 7 men who had acute barotitis (incidence of 2.3%) and 28 men who had delayed ear pain (incidence of 9.2%). A significant association resulted between history of ENT diseases and delayed ear pain and between abnormal ENT findings and acute barotitis in subjects exposed to the higher profile. Altitude was associated with increased risk of delayed ear pain. Delayed ear pain was associated with older age in subjects exposed to the lower altitude and younger age in subjects exposed to the higher altitude. DISCUSSION: Our data suggest that in subjects exposed to 35,000 ft (10,668 m), the history of previous ENT diseases and younger age may be valid predictors of delayed ear pain, while abnormal ENT findings may predict acute barotitis. At 25,000 ft (7620 m), subjects with older age may have increased risk of delayed ear pain.

Cerebral vascular response in airmen exposed to hypobaric hypoxia.

INTRODUCTION: Cerebral vascular response via local and reflex adjustments is part of the integrated response to hypoxia and is coupled with changes in systemic vascular resistances that allow a redistribution of blood flow toward the brain. The cerebral vascular response in airmen exposed to simulated high altitude is not clear, thus we sought to investigate this aspect. METHODS: Four healthy military airmen were exposed to simulated high altitude in a hypobaric chamber according to a standard training protocol. Blood saturation (SpO2) and blood flow velocity with transcranial Doppler from the left middle cerebral artery (Vm) were continuously recorded. Pulsatility Index (PI), resistance index (RI), and systolic/diastolic ratio (S/D ratio) were computed. Alternate hypoxia-hyperoxia trials for 2 and 1 min, respectively, were used to assess the cerebrovascular response. RESULTS: Acute hypoxia induced an increase in Vm that promptly recovered when the oxygen supply was restored (mean increase of 5.5% at 18,000 ft and 17.2% at 25,000 ft). Alternate hypoxia-hyperoxia at 25,000 and 18,000 ft elicited changes in both SpO2 and Vm. In hypoxia, PI significantly decreased (mean decrease o" 25.6% at 18,000 ft and 39.5% at 25,000 ft), as did RI (mean decrease of 18.7% at 18,000 ft and 34.4% at 25,000 ft), while S/D ratio increased. DISCUSSION: The standard altitude training protocol induced a transient cerebrovascular response. The response was as expected, with hypoxia-induced vasodilation and opposite changes when breathing pure oxygen.

Altitude chamber related adverse effects among 1241 airmen.

INTRODUCTION: Altitude chambers are used for training aircrews, but incidents have been reported, including decompression sickness (DCS) and barotrauma. To minimize chamber-related adverse effects we implemented a set of measures, including altitude restriction and a pre-chamber clinical selection (PCS) of subjects before exposure. METHODS: We reviewed our records regarding 1254 individuals who were trained from 2003 to 2009. After the first 3 subjects, the maximum altitude of the highest training profile was limited to 43,000 ft (13,106.4 m) instead of 45,000 ft (13,716 m) and, after the first 327 subjects, a clinical evaluation of each trainee was performed by an otolaryngologist before altitude exposure. The evaluation included otoscopy and tympanometry, and subjects with abnormal results were not cleared for altitude exposure. Subjects were grouped by having undergone the highest profile before (3 subjects) or after altitude restriction (8 subjects) and received clinical selection (PCS group, 927 subjects) or not (control group, 327 subjects). RESULTS: We recorded 32 total adverse effects (overall incidence 2.6%), 21 in the PCS group (2.3%) and 11 in the control group (3.4%). The difference between groups was not significant. Adverse effects included 19 cases of acute barotitis (1.5%), 1 case of DCS (0.08%), and 4 cases of syncope (0.3%). The incidence of barotitis was 1.1% in the PCS group and 2.7% in the control group. The altitude restriction was ineffective in preventing both barotrauma and DCS. CONCLUSIONS: The incidence of adverse effects in our subjects was low and pre-chamber clinical selection appeared to be effective in reducing the risk of barotitis.

Ear pain after breathing oxygen at altitude: prevalence and prevention of delayed barotrauma.

INTRODUCTION: Military pilots frequently report ear pain with onset several hours after altitude exposure while breathing pure oxygen, but the prevalence of this problem is unknown. A similar problem is described in divers after breathing hyperbaric oxygen and it is related to the oxygen contained in the middle ear. METHODS: In order to assess the prevalence of delayed ear pain after altitude exposure and investigate the effectiveness of preventive use of a nasal balloon (NB), we studied 88 healthy military jet pilots who were asymptomatic after altitude chamber exposure which included 100% oxygen breathing. A group of 44 subjects received the NB shortly after the chamber and they were advised to use it every hour before going to sleep. A control group of 44 subjects was requested to perform the Valsalva maneuver alone over the same period. All subjects underwent clinical examination by an otolaryngologist and tympanometry just before the chamber exposure and again the day after. RESULTS: The day after the altitude exposure, 53.4% of subjects reported ear pain. In the treated group, 61.4% of subjects were free of symptoms, compared to 31.8% in the control group (P < 0.01). Tympanogram was abnormal in eight symptomatic subjects and in six asymptomatic. CONCLUSION: Our data suggest that in our subjects there is high prevalence of delayed ear barotrauma after altitude chamber exposure while breathing pure oxygen and the tympanogram may improve the accuracy of the diagnosis in asymptomatic subjects. The nasal balloon appears to be effective for prevention.

Acute otitic barotrauma during hypobaric chamber training: prevalence and prevention.

INTRODUCTION: Barotitis media is known to be an adverse effect of altitude changes, but few studies have investigated this condition with respect to hypobaric chamber training and the resulting estimations of prevalence vary. METHODS: In order to assess the prevalence of hypobaric chamber-related barotitis and evaluate a method of prevention, 335 healthy military pilots undergoing high altitude training were subject to clinical examination and tympanometry before entering the chamber. In order to minimize the risk of barotrauma, only subjects with normal preflight findings were cleared for altitude exposure. Barotitis media was diagnosed on the basis of ear pain and clinical findings according to Teed's classification. RESULTS: Barotitis occurred in eight subjects; seven cases were monolateral and one bilateral, prevalence was 2.4%. CONCLUSION: The prevalence of barotitis after hypobaric chamber training is low in our study, suggesting that a pre-chamber medical check including clinical examination and tympanometry could be effective in identifying subjects at risk.