- Email: [email protected]
Flying and midface fractures: the truth is out there
Int. J. Oral Maxillofac. Surg. 2013; 42: 1506–1509 http://dx.doi.org/10.1016/j.ijom.2013.06.001, available online at http://www.sciencedirect.com
Clinical Paper Trauma
Flying and midface fractures: the truth is out there E. Tan-Gore, R. Thanigaivel, B. Wilson, A. Thomas, M. E. Thomas: Flying and midface fractures: the truth is out there. Int. J. Oral Maxillofac. Surg. 2013; 42: 1506– 1509. Crown Copyright # 2013 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved. Abstract. There are no clear, evidence-based guidelines that dictate when it is safe for a patient to fly after sustaining a midface fracture. From January 2006 to December 2009, the Royal Darwin Hospital Maxillofacial Unit had 48 out of 201 patients with an orbital fracture that involved a paranasal air sinus transported by a variety of aircraft to the unit for definitive management. No orbital complications were recorded for the 24% of patients requiring air travel to our tertiary referral centre. Furthermore, there were no recorded deviations from the standard flight plan. We believe that this demonstrates there are no absolute contraindications to flying on a variety of aircraft with a midface fracture, but clinical assessment remains crucial for an informed decision to transport these patients by air.
Fractures involving the midface often involve an adjacent air sinus. In the absence of evidence-based guidelines, expert opinion advocates that such patients avoid flying for a period of 2 weeks after injury,1,2 whether the fractures are treated conservatively or operatively. This advice is based on an understanding of the physics of the paranasal sinuses and air travel, and on expert opinion. However, there is no evidence in the current literature to support this advice. The Royal Darwin Hospital (RDH) is the single tertiary referral centre for all facial trauma in the Northern Territory (NT) of Australia, and provides a service for all victims of facial trauma in an area that covers almost 1.5 million square kilometres. The travel time by road to reach RDH can take over 24 h from some locations, and the roads are impassable during certain parts of the year. Air travel is the 0901-5027/01201506 + 04 $36.00/0
most time-efficient manner by which to transport patients in the NT. It is, in some cases, unavoidable as alternate road-based transport forms are rendered impossible by the tyranny of remoteness and due to extreme weather conditions, e.g. floods. Furthermore, remote clinics may lack the resources to definitively image patients in cases of suspected facial fractures, and travel to RDH must be organized without the benefit of confirmation of the presence of these injuries prior to transfer. We reviewed all cases of patients who had been flown to the RDH for the management of maxillofacial trauma and who had radiological confirmation of midface fractures. We limited our review to those patients with an orbital fracture and communication into the adjacent sinus, e.g. orbital floor fracture with communication into the corresponding maxillary sinus. We excluded isolated nasal bone fractures
E. Tan-Gore1, R. Thanigaivel2, B. Wilson3, A. Thomas3, M. E. Thomas1 1 Department of Maxillofacial/Head and Neck Surgery, Royal Darwin Hospital, Northern Territory, Australia; 2Finders University, Adelaide, South Australia, Australia; 3James Cook University, Townsville, Queensland, Australia
Key words: maxillofacial; trauma; midface; air travel; flying; guidelines; recommendations. Accepted for publication 3 June 2013 Available online 4 July 2013
that did not involve the paranasal sinuses. In doing so, we aimed to elucidate the effect of flying on patients with midface fractures, and in particular, on those with fractures where there was potential for exertion of a pressure effect from the gas in the adjacent anatomical air space into the orbital cavity. Materials and methods
Utilizing unit records and the Department’s trauma database, we retrieved the details of all patients who suffered a midface fracture over a 3-year period, between January 2006 and December 2009. These details were cross-referenced with the Patient Accommodation and Travel Service (PATS) records, which is the NT Government’s travel organization for subsidized transport for medical treatment. All patients requiring transport for
Crown Copyright # 2013 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
1507
Flying and midface fractures
Table 1. Locations, distance by road, average flight time, and number of patients transported from the location to the RDH.
medical treatment within the NT are entitled to this subsidy. Patients requiring transport for medical treatment interstate are also entitled to this subsidy. The mode of transport can be either by road or by air travel, and is determined by the PATS team based upon the availability of the various transport modes. There are remote locations where travel by road (either by car or bus) is not possible due to distance or lack of a sealed road. The data from the PATS records were collated by a single member of the research team. We reviewed the charts, electronic notes, and radiology of the relevant patients. In particular, we looked at the following parameters: (1) the location of the midfacial injury. (2) Whether patients arrived at RDH with any new complications, including orbital emphysema, visual loss, and sinus pain. The complications were recorded only if they occurred during or after the flight, and were not present prior to the flight. (3) Whether patients had symptoms during the flight, at altitude, which required a change in flight path, altitude, or any other intervention. We also recorded the air services utilized by the PATS to transport patients to Darwin. We then performed an internet search to determine the specific aircraft used by the respective air services, and we looked at the maximum altitude capabilities of the aircraft. The inclusion criteria for this study were: patients with orbital fractures that involved the adjacent air sinus and who were flown with their fresh fractures for treatment.
flights. This time delay can vary significantly and is dependent on a variety of factors, including departure schedule, priority (in the case of aeromedical retrieval services), location of an escort for the patient, and extreme weather. The average duration of flight during transport varies depending upon the type of flight (e.g. aeromedical retrieval or commercial, helicopter, or fixed-wing aircraft). The longest flight was from Port Keats to Darwin, totalling an approximate flight time of 5 h on a fixed-wing aircraft (Table 1). The three most common aircraft utilized during the study period were the Boeing 717, Beechcraft Super King Air, and the Metroliner Fairchild Metro 23. All of
Results
Table 2. List of aircraft flown in Northern Territory and their maximum altitudes.
Two hundred and one patients presented to the RDH Maxillofacial Unit with orbital fractures that involved the adjacent air sinus during the 3-year period from January 2006 to December 2009. Forty-eight of these patients were transported by air to the RDH. This represents 24% of all patients with orbital fractures. A chart review of the 48 patients was performed and any complications entered into a Microsoft Excel spreadsheet. No further information about the patients was recorded. The minimum delay recorded for a patient to be assessed and managed prior to air travel to the RDH is approximately 2 h. This includes the time required for assessment and initial management of the patient, discussion with the ‘on call’ maxillofacial registrar, and organization of
Distance by road; Google Mapsa
Location Alice Springs Gove Katherine Maningrida Port Keats/Wadeye Daly River Borroloola Groote Eylandt Gapuwiyak Milingimbi Elcho Island East Arnhem MacArthur Mines Total
Number of patients
Average flight time
1497 km 2h 1031.6 km 1.5 h 316.1 km 1h 511.1 km 1 h Maningrida; 3 h Pearl Aviation 393.6 km 1 h Pearl Aviation; 5 h Murin 222 km 1h 970 km Not recordedb Requires sea crossing 1.75 h 885 km Not recordedb Requires sea crossing 1 h Requires sea crossing 2 h total; 2 flights of 1 h duration 636 km Not recordedb 1016 km Not recordedb
14 10 6 4 3 2 2 2 1 1 1 1 1 48
RDH, Royal Darwin Hospital. a Available at: http://maps.google.com.au. b Not recorded on the Patient Accommodation and Travel Service system due to aeromedical retrieval or chartered flights. This information is not publicly available.
these craft have pressurized cabins and the maximum altitude that the aircraft can reach ranges from 7600 to 11,300 m (Table 2). In addition to these aircraft, CareFlight, a medical retrieval organization, utilizes unpressurized helicopters in both patient rescue and transfer scenarios. The maximum altitude flown by these aircraft is 4572 m during the period of observation. The most common orbital skeletal injuries sustained by the patients in the audit were zygomatic complex fractures (including orbital fracture) and isolated orbital floor fractures (Table 3). There were no complications resulting from air travel recorded in the initial presentation notes of these patients.
Aircraft
Company
Maximum altitude
Qantas
Boeing 717-220
11,300 m (37,100 ft)
Pearl Aviation
B200 King Air Metro 23 Airliner
10,668 m (35,000 ft) 7600 m (25,000 ft)
RFDS
Pilatus PC 12
9144 m (30,000 ft)
AirNorth
Embraer 170 Embraer EMB 120 Brasilia Fairchild Metro 23
11,900 m (39,000 ft) 9144 m (30,000 ft) 7620 m (25,000 ft)
CareFlight
Helicopter, Helicopter, Helicopter, B200 King
4572 m (15,000 ft) 6096 m (20,000 ft) 6069 m (20,000 ft) 10,668 m (35,000 ft)
Vincent Aviation
Beechcraft 1900 SAAB 340 BAe146
7600 m (25,000 ft) 9450 m (31,000 ft) 8840 m (29,000 ft)
Aboriginal Air Murin Chartered unspecified
Pilatus PC 12 Unavailable Unavailable
9144 m (30,000 ft) Unavailable Unavailable
Kawasaki BK117 B2 Agusta A109E Bell 412EP Air
1508
Tan-Gore et al.
Table 3. Classification of orbital fracture (AO Foundation Online Surgical Referencea) and total number of fractures. Classification Orbital floor Medial wall Orbital roof Lateral wall Naso-orbito-ethmoidal Zygomatic complex (including orbit) Le Forte II Le Forte III a
Total number of cases 15 5 2 2 9 18 3 1
Available at: http://www2.aofoundation.
org.
Discussion
Policies discouraging air travel in patients with facial fractures are based on the physics of gas principles. Boyle’s law states that, at constant temperature, the absolute pressure and the volume of a gas are inversely proportional.3 This means that ascending to an altitude (decreasing pressure) will increase the volume, whilst descending (increasing pressure) will decrease the volume and cause contraction.4 Contrary to popular belief, modern aircraft are not pressurized to sea level equivalent.5 On most flights the cabin altitude will be between 5000 and 8000 feet (1524 m and 2438 m).5 Fractures of the medial orbital wall and floor allow direct communication between the airfilled sinuses and the orbit, allowing air to enter the orbit.3 Therefore, strict application of Boyle’s law for midface fractures would be that gas in the communicating sinus of a facial fracture would expand (increase in volume of the gas) during flight, causing complications including subcutaneous emphysema (within soft tissue) and orbital emphysema (within the orbital cavity). Furthermore, where volume is restricted (e.g. orbital cavity), there will be a relative increase in pressure in accordance with Boyle’s law,6 which could lead to an orbital compartment syndrome and to permanent visual loss. Complications arising from flying with an orbital fracture are reported in the literature but are restricted to case reports. Monaghan and Millar7 reported a case of orbital emphysema that developed during air travel in a patient with a previously undiagnosed orbital floor fracture. In that case, the patient developed intense pain, swollen periorbital tissues, and diplopia during the commercial flight. Post-flight computed tomography (CT) imaging was
performed to confirm the fracture. The patient’s symptoms resolved postsurgery.7 In this case, Monaghan and Millar7 postulated that the increased atmospheric pressure during descent forced air from the maxillary sinus into the orbital cavity, and that the fine fracture line did not allow equalization of the tension within the orbit with the maxillary sinus. Orbital emphysema is a well-recognized complication of fractures involving the orbit and is seen on conventional radiographs in two-thirds of patients with orbital fractures.8 This commonly occurs in the setting of nose-blowing following facial injury. Increased pain, swelling, and visual changes are often the catalyst for patients with previously unknown orbital fractures to present to the emergency department. Permanent and acute visual loss as a result of orbital emphysema has been reported in the literature,9,10 but is a rare occurrence, and in the majority of cases, orbital emphysema resolves without the need for surgical intervention. Orbital compartment syndrome is an uncommon, ophthalmic surgical emergency characterized by an acute rise in orbital pressure.11 Common causes include acute orbital haemorrhage due to trauma, surgery, local injections, and preexisting medical conditions.11 Patients may complain of acute-onset decreased vision, double vision, painful periorbital oedema, or proptosis, developing rapidly over a period of minutes to hours.11 Orbital emphysema resulting in orbital compartment syndrome has been described in compressed air injuries.12 However, orbital haemorrhage is the common aetiology here, and orbital compartment syndrome resulting from orbital emphysema causing permanent visual loss remains a rare phenomenon and restricted to cases where large amounts of gas are introduced to the orbital cavity from external sources. Furthermore, the natural course of orbital compartment syndrome arises within minutes to hours, which is approximately equivalent to the time that elapses between patient injury, presentation to medical care, assessment, investigations, initial management, and subsequent transfer. The signs and symptoms of orbital compartment syndrome and the need to act swiftly would have occurred long before the patient is flown. Generally, the expert opinion is to advise patients to refrain from flying for 2 weeks, regardless of the treatment option.1–3 Airlines may request further information from medical practitioners before granting clearance to travel. There are currently no evidence-based guide-
lines as to when it is safe to travel after midface fracture. Mahmood et al.1 reported that a significant number of oral and maxillofacial surgeons did not advise any avoidance of flying following zygomatic fractures, dependent upon the treatment (40%, 42%, and 47% after open reduction and internal fixation, closed reduction, and non-operative management, respectively). It is noteworthy that 90% of the respondents in that study based their advice on common sense and traditional practice, and only 5% of respondents stated that their advice was based on published research/evidence. The AO Surgery Reference also states that travel in commercial airlines is permitted following orbital fractures, but warns that mild pain on descent may be noticed.13 In our case series, we noted that no patients developed any new complications on arrival to the RDH after flying on any aircraft. There were no changes that required a change in the flight path or in altitude. No patient notes were recorded to suggest that the patient’s initial presentation varied from that which is usually expected in the case of orbital fractures. The distribution of the types of orbital fractures in the case series is in line with the pattern of orbital fractures noted in other case series, with zygomatic complex (including the orbit) and orbital floor fractures being the most common injuries noted. Although there are reported cases of significant complications arising from flying and from orbital emphysema, it is our assertion that there is no absolute contraindication to flying with an orbital fracture, either before or after treatment. Patient discomfort may be expected and should be discussed with the patient, but it is consistent with that which can be reasonably expected in any patient with risk factors for pressure-related symptoms during air travel, including pain and swelling. A communication exists between the orbital cavity and the maxillary sinus in cases of medial or orbital floor fracture, which expands the volume of the orbital compartment, minimizing the risk of orbital compartment syndrome. Orbital emphysema is discussed as a complication of flying with an orbital fracture, but this author asserts that this is a common symptom of the orbital fracture itself, and is not exacerbated by changes in altitude for the reasons discussed above. The current expert consensus that precludes air travel for patients with midface fractures is based on weak evidence (Level 5: Mechanism-based reasoning; UK National Health Service, Oxford Centre
Flying and midface fractures for Evidence-Based Medicine). In our case series, we recorded no complications despite an air travel rate of 24% for all orbital fractures over a sustained period of time, in consecutive patients. We would question the rationale behind the advice to avoid flying after an orbital fracture. The evidence that we have presented indicates that flying with an orbital fracture is not likely to cause damage to the person, or disruption of the flight. While the decision to transfer a patient with a suspected or confirmed orbital fracture remains in the hands of the clinician, it is important that the evidence as present is considered and an informed decision made after careful evaluation. Funding
None. Competing interests
None declared. Ethical approval
Not required.
References 1. Mahmood S, Keith DJ, Lello GE. When can patients blow their nose and fly after treatment for fractures of zygomatic complex: the need for consensus. Injury 2003;34:908–11. 2. Lynham A, Tuckett J, Warnke P. Maxillofacial trauma. Aust Fam Physician 2012;41: 172–80. 3. Seiff SR. Atmospheric pressure changes and the orbit: recommendations for patients after orbital trauma or surgery. Ophthal Plast Reconstr Surg 2002;18:239–41. 4. Fonseca RJ. Oral and maxillofacial trauma. 3rd ed. St Louis, MO: Elsevier; 2005 : 98–102. 5. Medical guidelines for airline travel: 2nd ed.. Aerospace Medical Association Medical Guidelines Task Force. Aviat Space Environ Med 2003;74(5 Suppl.):A1–A19. 6. Milligan JE, Jones CN, Helm DR, Munford BJ. The principles of aeromedical retrieval of the critically ill. Trends Anaesth Crit Care 2011;1:22–6. 7. Monaghan AM, Millar BG. Orbital emphysema during air travel: a case report. J Craniomaxillofac Surg 2002;30:367–8. 8. Birrer RB, Robinson T, Papachristos P. Orbital emphysema: how common, how significant. Ann Emerg Med 1994;24:1115–8.
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9. Linberg J. Orbital emphysema complication by acute retinal artery occlusion: a case report and treatment. Ann Ophthalmol 1982;14: 747–9. 10. Jordan DR, White Jr GL, Anderson RL. Orbital emphysema: staging and acute management. Ann Emerg Med 1998;101: 960–6. 11. Lima V, Burt B, Leibovitch I, Prabhakaran V, Goldberg RA, Selva D. Orbital compartment syndrome: the ophthalmic surgical emergency. Surv Ophthalmol 2009;54: 441–9. 12. Caesar R, Gajus M, Davies R. Compressed air injury of the orbit in the absence of external trauma. Eye 2003;17:661–2. 13. Ellis III E, Shimozato K. AO Foundation surgery reference: aftercare—orbital floor fracture. 2009.
Address: Royal Darwin Hospital PO Box 41326 Casuarina NT 0811 Australia Tel.: +61 8 8922 8888 fax: +61 8 8922 7822 E-mails: [email protected], [email protected]
Clinical Paper Trauma
Flying and midface fractures: the truth is out there E. Tan-Gore, R. Thanigaivel, B. Wilson, A. Thomas, M. E. Thomas: Flying and midface fractures: the truth is out there. Int. J. Oral Maxillofac. Surg. 2013; 42: 1506– 1509. Crown Copyright # 2013 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved. Abstract. There are no clear, evidence-based guidelines that dictate when it is safe for a patient to fly after sustaining a midface fracture. From January 2006 to December 2009, the Royal Darwin Hospital Maxillofacial Unit had 48 out of 201 patients with an orbital fracture that involved a paranasal air sinus transported by a variety of aircraft to the unit for definitive management. No orbital complications were recorded for the 24% of patients requiring air travel to our tertiary referral centre. Furthermore, there were no recorded deviations from the standard flight plan. We believe that this demonstrates there are no absolute contraindications to flying on a variety of aircraft with a midface fracture, but clinical assessment remains crucial for an informed decision to transport these patients by air.
Fractures involving the midface often involve an adjacent air sinus. In the absence of evidence-based guidelines, expert opinion advocates that such patients avoid flying for a period of 2 weeks after injury,1,2 whether the fractures are treated conservatively or operatively. This advice is based on an understanding of the physics of the paranasal sinuses and air travel, and on expert opinion. However, there is no evidence in the current literature to support this advice. The Royal Darwin Hospital (RDH) is the single tertiary referral centre for all facial trauma in the Northern Territory (NT) of Australia, and provides a service for all victims of facial trauma in an area that covers almost 1.5 million square kilometres. The travel time by road to reach RDH can take over 24 h from some locations, and the roads are impassable during certain parts of the year. Air travel is the 0901-5027/01201506 + 04 $36.00/0
most time-efficient manner by which to transport patients in the NT. It is, in some cases, unavoidable as alternate road-based transport forms are rendered impossible by the tyranny of remoteness and due to extreme weather conditions, e.g. floods. Furthermore, remote clinics may lack the resources to definitively image patients in cases of suspected facial fractures, and travel to RDH must be organized without the benefit of confirmation of the presence of these injuries prior to transfer. We reviewed all cases of patients who had been flown to the RDH for the management of maxillofacial trauma and who had radiological confirmation of midface fractures. We limited our review to those patients with an orbital fracture and communication into the adjacent sinus, e.g. orbital floor fracture with communication into the corresponding maxillary sinus. We excluded isolated nasal bone fractures
E. Tan-Gore1, R. Thanigaivel2, B. Wilson3, A. Thomas3, M. E. Thomas1 1 Department of Maxillofacial/Head and Neck Surgery, Royal Darwin Hospital, Northern Territory, Australia; 2Finders University, Adelaide, South Australia, Australia; 3James Cook University, Townsville, Queensland, Australia
Key words: maxillofacial; trauma; midface; air travel; flying; guidelines; recommendations. Accepted for publication 3 June 2013 Available online 4 July 2013
that did not involve the paranasal sinuses. In doing so, we aimed to elucidate the effect of flying on patients with midface fractures, and in particular, on those with fractures where there was potential for exertion of a pressure effect from the gas in the adjacent anatomical air space into the orbital cavity. Materials and methods
Utilizing unit records and the Department’s trauma database, we retrieved the details of all patients who suffered a midface fracture over a 3-year period, between January 2006 and December 2009. These details were cross-referenced with the Patient Accommodation and Travel Service (PATS) records, which is the NT Government’s travel organization for subsidized transport for medical treatment. All patients requiring transport for
Crown Copyright # 2013 Published by Elsevier Ltd on behalf of International Association of Oral and Maxillofacial Surgeons. All rights reserved.
1507
Flying and midface fractures
Table 1. Locations, distance by road, average flight time, and number of patients transported from the location to the RDH.
medical treatment within the NT are entitled to this subsidy. Patients requiring transport for medical treatment interstate are also entitled to this subsidy. The mode of transport can be either by road or by air travel, and is determined by the PATS team based upon the availability of the various transport modes. There are remote locations where travel by road (either by car or bus) is not possible due to distance or lack of a sealed road. The data from the PATS records were collated by a single member of the research team. We reviewed the charts, electronic notes, and radiology of the relevant patients. In particular, we looked at the following parameters: (1) the location of the midfacial injury. (2) Whether patients arrived at RDH with any new complications, including orbital emphysema, visual loss, and sinus pain. The complications were recorded only if they occurred during or after the flight, and were not present prior to the flight. (3) Whether patients had symptoms during the flight, at altitude, which required a change in flight path, altitude, or any other intervention. We also recorded the air services utilized by the PATS to transport patients to Darwin. We then performed an internet search to determine the specific aircraft used by the respective air services, and we looked at the maximum altitude capabilities of the aircraft. The inclusion criteria for this study were: patients with orbital fractures that involved the adjacent air sinus and who were flown with their fresh fractures for treatment.
flights. This time delay can vary significantly and is dependent on a variety of factors, including departure schedule, priority (in the case of aeromedical retrieval services), location of an escort for the patient, and extreme weather. The average duration of flight during transport varies depending upon the type of flight (e.g. aeromedical retrieval or commercial, helicopter, or fixed-wing aircraft). The longest flight was from Port Keats to Darwin, totalling an approximate flight time of 5 h on a fixed-wing aircraft (Table 1). The three most common aircraft utilized during the study period were the Boeing 717, Beechcraft Super King Air, and the Metroliner Fairchild Metro 23. All of
Results
Table 2. List of aircraft flown in Northern Territory and their maximum altitudes.
Two hundred and one patients presented to the RDH Maxillofacial Unit with orbital fractures that involved the adjacent air sinus during the 3-year period from January 2006 to December 2009. Forty-eight of these patients were transported by air to the RDH. This represents 24% of all patients with orbital fractures. A chart review of the 48 patients was performed and any complications entered into a Microsoft Excel spreadsheet. No further information about the patients was recorded. The minimum delay recorded for a patient to be assessed and managed prior to air travel to the RDH is approximately 2 h. This includes the time required for assessment and initial management of the patient, discussion with the ‘on call’ maxillofacial registrar, and organization of
Distance by road; Google Mapsa
Location Alice Springs Gove Katherine Maningrida Port Keats/Wadeye Daly River Borroloola Groote Eylandt Gapuwiyak Milingimbi Elcho Island East Arnhem MacArthur Mines Total
Number of patients
Average flight time
1497 km 2h 1031.6 km 1.5 h 316.1 km 1h 511.1 km 1 h Maningrida; 3 h Pearl Aviation 393.6 km 1 h Pearl Aviation; 5 h Murin 222 km 1h 970 km Not recordedb Requires sea crossing 1.75 h 885 km Not recordedb Requires sea crossing 1 h Requires sea crossing 2 h total; 2 flights of 1 h duration 636 km Not recordedb 1016 km Not recordedb
14 10 6 4 3 2 2 2 1 1 1 1 1 48
RDH, Royal Darwin Hospital. a Available at: http://maps.google.com.au. b Not recorded on the Patient Accommodation and Travel Service system due to aeromedical retrieval or chartered flights. This information is not publicly available.
these craft have pressurized cabins and the maximum altitude that the aircraft can reach ranges from 7600 to 11,300 m (Table 2). In addition to these aircraft, CareFlight, a medical retrieval organization, utilizes unpressurized helicopters in both patient rescue and transfer scenarios. The maximum altitude flown by these aircraft is 4572 m during the period of observation. The most common orbital skeletal injuries sustained by the patients in the audit were zygomatic complex fractures (including orbital fracture) and isolated orbital floor fractures (Table 3). There were no complications resulting from air travel recorded in the initial presentation notes of these patients.
Aircraft
Company
Maximum altitude
Qantas
Boeing 717-220
11,300 m (37,100 ft)
Pearl Aviation
B200 King Air Metro 23 Airliner
10,668 m (35,000 ft) 7600 m (25,000 ft)
RFDS
Pilatus PC 12
9144 m (30,000 ft)
AirNorth
Embraer 170 Embraer EMB 120 Brasilia Fairchild Metro 23
11,900 m (39,000 ft) 9144 m (30,000 ft) 7620 m (25,000 ft)
CareFlight
Helicopter, Helicopter, Helicopter, B200 King
4572 m (15,000 ft) 6096 m (20,000 ft) 6069 m (20,000 ft) 10,668 m (35,000 ft)
Vincent Aviation
Beechcraft 1900 SAAB 340 BAe146
7600 m (25,000 ft) 9450 m (31,000 ft) 8840 m (29,000 ft)
Aboriginal Air Murin Chartered unspecified
Pilatus PC 12 Unavailable Unavailable
9144 m (30,000 ft) Unavailable Unavailable
Kawasaki BK117 B2 Agusta A109E Bell 412EP Air
1508
Tan-Gore et al.
Table 3. Classification of orbital fracture (AO Foundation Online Surgical Referencea) and total number of fractures. Classification Orbital floor Medial wall Orbital roof Lateral wall Naso-orbito-ethmoidal Zygomatic complex (including orbit) Le Forte II Le Forte III a
Total number of cases 15 5 2 2 9 18 3 1
Available at: http://www2.aofoundation.
org.
Discussion
Policies discouraging air travel in patients with facial fractures are based on the physics of gas principles. Boyle’s law states that, at constant temperature, the absolute pressure and the volume of a gas are inversely proportional.3 This means that ascending to an altitude (decreasing pressure) will increase the volume, whilst descending (increasing pressure) will decrease the volume and cause contraction.4 Contrary to popular belief, modern aircraft are not pressurized to sea level equivalent.5 On most flights the cabin altitude will be between 5000 and 8000 feet (1524 m and 2438 m).5 Fractures of the medial orbital wall and floor allow direct communication between the airfilled sinuses and the orbit, allowing air to enter the orbit.3 Therefore, strict application of Boyle’s law for midface fractures would be that gas in the communicating sinus of a facial fracture would expand (increase in volume of the gas) during flight, causing complications including subcutaneous emphysema (within soft tissue) and orbital emphysema (within the orbital cavity). Furthermore, where volume is restricted (e.g. orbital cavity), there will be a relative increase in pressure in accordance with Boyle’s law,6 which could lead to an orbital compartment syndrome and to permanent visual loss. Complications arising from flying with an orbital fracture are reported in the literature but are restricted to case reports. Monaghan and Millar7 reported a case of orbital emphysema that developed during air travel in a patient with a previously undiagnosed orbital floor fracture. In that case, the patient developed intense pain, swollen periorbital tissues, and diplopia during the commercial flight. Post-flight computed tomography (CT) imaging was
performed to confirm the fracture. The patient’s symptoms resolved postsurgery.7 In this case, Monaghan and Millar7 postulated that the increased atmospheric pressure during descent forced air from the maxillary sinus into the orbital cavity, and that the fine fracture line did not allow equalization of the tension within the orbit with the maxillary sinus. Orbital emphysema is a well-recognized complication of fractures involving the orbit and is seen on conventional radiographs in two-thirds of patients with orbital fractures.8 This commonly occurs in the setting of nose-blowing following facial injury. Increased pain, swelling, and visual changes are often the catalyst for patients with previously unknown orbital fractures to present to the emergency department. Permanent and acute visual loss as a result of orbital emphysema has been reported in the literature,9,10 but is a rare occurrence, and in the majority of cases, orbital emphysema resolves without the need for surgical intervention. Orbital compartment syndrome is an uncommon, ophthalmic surgical emergency characterized by an acute rise in orbital pressure.11 Common causes include acute orbital haemorrhage due to trauma, surgery, local injections, and preexisting medical conditions.11 Patients may complain of acute-onset decreased vision, double vision, painful periorbital oedema, or proptosis, developing rapidly over a period of minutes to hours.11 Orbital emphysema resulting in orbital compartment syndrome has been described in compressed air injuries.12 However, orbital haemorrhage is the common aetiology here, and orbital compartment syndrome resulting from orbital emphysema causing permanent visual loss remains a rare phenomenon and restricted to cases where large amounts of gas are introduced to the orbital cavity from external sources. Furthermore, the natural course of orbital compartment syndrome arises within minutes to hours, which is approximately equivalent to the time that elapses between patient injury, presentation to medical care, assessment, investigations, initial management, and subsequent transfer. The signs and symptoms of orbital compartment syndrome and the need to act swiftly would have occurred long before the patient is flown. Generally, the expert opinion is to advise patients to refrain from flying for 2 weeks, regardless of the treatment option.1–3 Airlines may request further information from medical practitioners before granting clearance to travel. There are currently no evidence-based guide-
lines as to when it is safe to travel after midface fracture. Mahmood et al.1 reported that a significant number of oral and maxillofacial surgeons did not advise any avoidance of flying following zygomatic fractures, dependent upon the treatment (40%, 42%, and 47% after open reduction and internal fixation, closed reduction, and non-operative management, respectively). It is noteworthy that 90% of the respondents in that study based their advice on common sense and traditional practice, and only 5% of respondents stated that their advice was based on published research/evidence. The AO Surgery Reference also states that travel in commercial airlines is permitted following orbital fractures, but warns that mild pain on descent may be noticed.13 In our case series, we noted that no patients developed any new complications on arrival to the RDH after flying on any aircraft. There were no changes that required a change in the flight path or in altitude. No patient notes were recorded to suggest that the patient’s initial presentation varied from that which is usually expected in the case of orbital fractures. The distribution of the types of orbital fractures in the case series is in line with the pattern of orbital fractures noted in other case series, with zygomatic complex (including the orbit) and orbital floor fractures being the most common injuries noted. Although there are reported cases of significant complications arising from flying and from orbital emphysema, it is our assertion that there is no absolute contraindication to flying with an orbital fracture, either before or after treatment. Patient discomfort may be expected and should be discussed with the patient, but it is consistent with that which can be reasonably expected in any patient with risk factors for pressure-related symptoms during air travel, including pain and swelling. A communication exists between the orbital cavity and the maxillary sinus in cases of medial or orbital floor fracture, which expands the volume of the orbital compartment, minimizing the risk of orbital compartment syndrome. Orbital emphysema is discussed as a complication of flying with an orbital fracture, but this author asserts that this is a common symptom of the orbital fracture itself, and is not exacerbated by changes in altitude for the reasons discussed above. The current expert consensus that precludes air travel for patients with midface fractures is based on weak evidence (Level 5: Mechanism-based reasoning; UK National Health Service, Oxford Centre
Flying and midface fractures for Evidence-Based Medicine). In our case series, we recorded no complications despite an air travel rate of 24% for all orbital fractures over a sustained period of time, in consecutive patients. We would question the rationale behind the advice to avoid flying after an orbital fracture. The evidence that we have presented indicates that flying with an orbital fracture is not likely to cause damage to the person, or disruption of the flight. While the decision to transfer a patient with a suspected or confirmed orbital fracture remains in the hands of the clinician, it is important that the evidence as present is considered and an informed decision made after careful evaluation. Funding
None. Competing interests
None declared. Ethical approval
Not required.
References 1. Mahmood S, Keith DJ, Lello GE. When can patients blow their nose and fly after treatment for fractures of zygomatic complex: the need for consensus. Injury 2003;34:908–11. 2. Lynham A, Tuckett J, Warnke P. Maxillofacial trauma. Aust Fam Physician 2012;41: 172–80. 3. Seiff SR. Atmospheric pressure changes and the orbit: recommendations for patients after orbital trauma or surgery. Ophthal Plast Reconstr Surg 2002;18:239–41. 4. Fonseca RJ. Oral and maxillofacial trauma. 3rd ed. St Louis, MO: Elsevier; 2005 : 98–102. 5. Medical guidelines for airline travel: 2nd ed.. Aerospace Medical Association Medical Guidelines Task Force. Aviat Space Environ Med 2003;74(5 Suppl.):A1–A19. 6. Milligan JE, Jones CN, Helm DR, Munford BJ. The principles of aeromedical retrieval of the critically ill. Trends Anaesth Crit Care 2011;1:22–6. 7. Monaghan AM, Millar BG. Orbital emphysema during air travel: a case report. J Craniomaxillofac Surg 2002;30:367–8. 8. Birrer RB, Robinson T, Papachristos P. Orbital emphysema: how common, how significant. Ann Emerg Med 1994;24:1115–8.
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9. Linberg J. Orbital emphysema complication by acute retinal artery occlusion: a case report and treatment. Ann Ophthalmol 1982;14: 747–9. 10. Jordan DR, White Jr GL, Anderson RL. Orbital emphysema: staging and acute management. Ann Emerg Med 1998;101: 960–6. 11. Lima V, Burt B, Leibovitch I, Prabhakaran V, Goldberg RA, Selva D. Orbital compartment syndrome: the ophthalmic surgical emergency. Surv Ophthalmol 2009;54: 441–9. 12. Caesar R, Gajus M, Davies R. Compressed air injury of the orbit in the absence of external trauma. Eye 2003;17:661–2. 13. Ellis III E, Shimozato K. AO Foundation surgery reference: aftercare—orbital floor fracture. 2009.
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