Traumatic diaphragmatic rupture: delayed presentation following a SCUBA dive

Discussion

TDR is a rare but serious occurrence whose incidence is approximately 0.8%–8% of trauma presentations and can remain undiagnosed for years.3–5 The two major mechanisms of injury are blunt trauma, such as in high-velocity motor vehicle accidents or falls, and penetrating injuries to the abdomen, such as gunshot or stab wounds.1 Hanna et al’s single institutional study of 105 patients demonstrated that TDR’s occurred more frequently in cases of blunt trauma.6 The pathophysiology of diaphragmatic rupture remains unclear; however, it has been postulated that the rapid and significant increase in intra-abdominal pressure results in transmitted kinetic energy through the diaphragm, causing tears in the posterolateral region and compromising its structural integrity.3 7

Our case describes a patient who developed a diaphragmatic rupture following a SCUBA dive. In diving, small changes in depth can result in significant pressure changes.8 9 For every 10 m of seawater, the pressure increases by one atmosphere. Barotrauma occurs when a gas-filled body space fails to equalise its pressure against that of the environment. In SCUBA diving, the most severe form of barotrauma would be pulmonary. Barotrauma secondary to intra-abdominal gas distension is not as commonly noted as other minor complications such as ear or sinus barotrauma.9 10 Based on Boyle’s law (pressure x volume=constant), a rapid ascent from a depth of 37 m would result in a significant 4.7-fold increase in the volume of air within the lungs and the gastrointestinal tract.9 11 In SCUBA diving, air swallowed during the dive results in gastric distention and thus, increased intra-abdominal pressure on rapid ascent as described, when the ambient pressure drops. The most common cause of a rapid ascent in the literature would be panic secondary to suspected equipment failure; however, in our case, we suspect that the rapid ascent and associated air swallowing after the unbearable pain felt during her descent, resulted in increased gastric distension and subsequent herniation through a potentially weakened diaphragm in the context of her history of a major MVA.12 13

To our knowledge, our case is the fourth reported case of delayed diaphragmatic rupture following a SCUBA dive.10 14 15 Of the three, the mechanism of injury described by Hayden et al differed from the rest as the patient presented 3 months following an uncomplicated Nissen fundoplication.10 Reports by both Baudoin et al and Chanson et al draw similarities as both cases involved patients who had previous history of blunt trauma.14 , 15 All three reports mentioned that emergency laparotomies were carried out. Conversely, our report shows that with delayed TDRs, laparoscopic repair is feasible with good results. We demonstrate that early endoscopic reduction and urgent laparoscopic repair is associated with excellent patient outcomes.

The South Pacific Underwater Medicine Society’s fourth edition guidelines on medical risk assessment for recreational diving published in 2010 by the Australian and New Zealand College of Anaesthetists include a non-exhaustive list of medical criteria that need to be satisfied in individuals who are considering undertaking recreational diving activities.16 As it stands, there is no mention of previous motor vehicle accidents or major (non-diving related) trauma in the questionnaire or guidelines. There is, however, a criterion under Section A4.11 regarding previous history of penetrating chest injuries that may be associated with an excessive risk of pulmonary barotrauma.16

Patients with TDR typically present with symptoms varying from minor, non-specific symptoms, such as mild dyspnoea or abdominal discomfort to severe obstructive symptoms and haemodynamic shock. In 1974, Grimes proposed a classification system for TDRs by categorising them into three phases of presentation: the acute phase, latent phase and the obstructive phase.17 The acute phase is described from the initial injury of diaphragm to recovery, the latent phase occurs when intra-abdominal contents begin to herniate through the diaphragmatic defect, and the obstructive phase can occur months or years after the initial injury, and is characterised as the phase where the herniated viscera becomes ischaemic, strangulated or obstructed, subsequently causing severe gastrointestinal symptoms and signs of cardiorespiratory compromise due to compression of the intrathoracic organs.17 18

Investigations that aid in the diagnosis of TDRs include CXR and CT. In the acute trauma setting, CXRs are performed routinely and can provide some signs of TDR, although non-specific in 20%–50% of patients.18 Some examples of specific CXR signs of TDR include dilated loops of bowel or air-fluid levels visualised within the thoracic cavity.19 20 CT scans have now become the preferred imaging modality for trauma cases, offering up to 78% sensitivity and 70%–100% specificity.19 21 22 They are also helpful in detecting small diaphragmatic injuries in some cases, particularly in penetrating injuries to the trunk that can be missed on CXRs.21 Despite the increased use of CT scans, they are not necessarily always diagnostic as there remain limitations to this modality, including slice thickness and respiratory motion artefacts, although these are gradually overcome with the use of multislice CT scans.22

Other forms of diagnostic investigations include thoracoscopy or laparoscopy, both of which have the added advantage of providing therapeutic management simultaneously. However, these are more relevant in the setting of acute diaphragmatic injuries. Villavicencio et al discussed the role of a video-assisted thoracoscopy (VAT) in patients with trauma and reported that VAT had a 98% accuracy in diagnosing diaphragmatic injuries.23 Similarly, Martinez et al described the use of VAT in facilitating the diagnosis of diaphragmatic injuries caused by penetrating trauma in the absence of clinical or radiographic evidence of intra-abdominal injuries requiring emergent surgery.24 Their paper also recommended the use of diagnostic laparoscopy in patients who had an equivocal clinical presentation and examination due to the high risk (65%) of associated intra-abdominal pathology.24 In our patient’s case, due to her delayed presentation, and as she remained haemodynamically stable, we opted for a less invasive investigative approach with a CT scan to rule out possible intra-abdominal pathologies prior to commencing with laparoscopic repair of the diaphragmatic defect.

The main principles of TDR repair include decompression and reduction of the hernia back into the abdominal cavity, and to ensure secure closure of the diaphragmatic defect. In emergent cases requiring surgery, a laparotomy is typically the preferred operative approach as this allows for adequate exposure of abdominal viscera, particularly where there is associated organ injury requiring urgent repair.25 In the cases of delayed diagnosis of TDR with no associated thoracoabdominal injuries, the repair can be performed via the minimally invasive laparoscopic or thoracoscopic approach.26 For primary repairs, multiple studies have advised for the use of non-absorbable sutures as they offer increased stability and subsequently reduce the risk of recurrence.12 26 27 TDR with larger defects can also be reinforced with synthetic mesh placement to allow for reduced tension during closure.28 This, however, is more applicable in the setting of a delayed presentation where scarring has occurred at the site of the defect. The use of mesh is typically not indicated in an acute diaphragmatic rupture.29