In our retrospective study, eight of 51 patients (16.7%) had undiagnosed diaphragm / chest / abdominal injuries during primary, secondary and radiological examinations. This is conform previous described incidence rates. All initially missed injuries were easily detected during thoracic inspection by thoracotomy or thoracoscopy and were surgically treated during the SSFR procedure. All the initially missed injuries were categorised as major or life threatening injuries according to Pfeiffer et al see Table 5, so early discovery contributes to enhancement of treatment.6) Retrospectively only 13 out of 56 CT-signs are positive for diaphragmatic ruptures, so even with the perioperative knowledge, still 77% of signs could not be confirmed by radiological findings. One patients didn’t have any positive CT-signs at all, with the given information, one may conclude that a diaphragm rupture cannot be excluded by a negative scan in trauma patients with rib fractures. One of the possible explanations could be found in the small difference in Hounsfield Units (HU) between the diaphragm and the adjacent visceral tissue (either the liver, spleen of stomach directly beneath the diaphragm or the (frequently seen) volume loss of the lung) on the side of the injury. In this respect, there was no clear difference between arterial and portal-venous scans. Combining this with a variable thickness of the diaphragm in both injured and healthy patients, proved to have a negative effect on visualisation of several of the described signs of diaphragm injury, especially the discontinuous diaphragm sign (without herniation) and the thickening of the diaphragm. Therefore we recommend, based on our experience, to perform a thoracic inspection during SSFR in trauma patients to prevent secondary surgical treatments and chronic complications due to missed injuries, until CT-scans and techniques significantly improve to diagnose diaphragm injuries.
Missed injuries selected at level of severity.
Missed injuries based on level of severity described by Pfeifer et al:
• Minor injuries: Hand, wrist, foot, ankle, forearm, uncomplex soft tissue injuries and fractures, rupture of ligaments and muscle tendons.
• Major injuries: Skull injuries, neurological and arterial lesions, liver, spleen, and intestinal lacerations, femoral, humeral, pelvic, and spine fractures and dislocations.
• Life threatening injuries: injuries of main vessels in thorax, haemothorax and pneumothorax.
A missed diaphragmatic rupture tends to become larger, and herniation of abdominal organs becomes more likely, particularly if the rupture is left-sided. Small right-sided injuries may remain stable due to the liver that tamponades the defect, preventing colon herniation. Nevertheless, repair of all left-sided and most right-sided diaphragmatic injuries should be performed when recognized due to the tendency to increase.11) Therefore, surgical treatment becomes difficult and more complications occur, when the rupture becomes chronic. A mortality rate of 30–60% has been described in patients with intrathoracic visceral herniation and strangulation after a missed diaphragmatic injury.10) With that, early detection of intrathoracic injuries contributes to increased survival rates and quality of life in trauma patients. Multiple studies and consensus statements have mentioned the possible benefits of adding a intrathoracic inspection during SSFR.12) Early evacuation of residual haemothorax during thoracic inspection by thoracoscopic surgery has proven to decrease the risk of infections, discomfort and shorten length of hospital stay among other advantages such as the possibility to directly repair lung lacerations and other intra-thoracic injuries.13,14) Other studies suggest that the with the use of thorascopic inspection, better visualisation of the fracture locations help to determine the optimal incision placement and therefore enhance minimally invasive methods with smaller incisions sides and less muscle loss.12,13) A complete thorascopic approach has only been performed in study design and is not suitable outside the context of research due to limitations of adequate tools. But despite these potential benefits more data has to be collected to support and recommend the routine use of thoracoscopy (or thoracotomy) during SSFR.12)
This study concerns trauma patients with severe injuries, causing a mean ISS of 28 points. Because of the major injuries in this cohort, intrathoracic injuries are more likely to occur. Therefore, the incidence of missed injuries, such as diaphragm ruptures, are higher and the diagnostic value of an inspection thoracoscopy or thoracotomy increases. With the recent shift towards surgical management of rib fractures, more research will estimate the incidence of missed injuries in less severe patients.
Limitations of this study is the small number of included cases without a control population. Patients with a missed diaphragm injury were not confirmed and a long-time follow-up and secondary surgical repair of those patients couldn’t be compared with early on surgical repair. Another limitation was the need for a thoracic surgeon with sufficient experience in VATS to perform a thoracoscopy during SSFR, therefor only one patient underwent a minimal invasive technique while almost the complete cohort underwent a thoracotomy. So difference in approach for intrathoracic inspection could not be compared.