Transdiaphragmatic Intercostal Hernia-An Unusual Hepatic Injury After a Car Accident: A Case Report and Review of the Literature

Transdiaphragmatic intercostal hernia, in which the abdominal contents of the hernia protrude through the diaphragm and the thoracic wall defect. is a very rare type of hernia with only a few cases having been reported in the literature. That type of hernia is usually manifested in male patients after trauma, penetrating or blunt. It is frequently presented with a palpable thoracic mass and pain. The indicated treatment is surgery. We present the case of a 60-year-old female admitted to the hospital after a car accident and suffered multiple rib fractures (6th, 7th, 8th right ribs / 7th, 8th, 9th left ribs), as well as flail thorax, hemothorax bilaterally, left subcutaneous emphysema and swelling of soft tissues of the right lateral thoracoabdominal wall. CT scan revealed herniation of hepatic parenchyma and intestinal loops into the thorax. The patient was treated surgically, and his postoperative course was uneventful. We also review the relevant literature concerning this transdiaphragmatic, intercostal hernia and identify 42 cases. Transdiaphragmatic intercostal hernia is a rare condition, usually manifested in male patients after trauma, penetrating or blunt. It is frequently presented with a palpable thoracic mass and pain. The indicated treatment is surgery.


INTRODUCTION
Transdiaphragmatic intercostal hernia (TDIH), also called intercostal pleuroperitoneal hernia, in which the abdominal contents of the hernia protrude through the diaphragm and the thoracic wall defect 1 , is a very rare hernia with only 42 cases having been reported in the literature 1- 33 . Table 1 presents in detail all of these cases.
These hernias develop following the disruption and separation of intercostal and diaphragmatic 2 muscles and are almost always acquired following trauma, penetrating or direct blunt, but can seldom present spontaneously 1, 17 .
The most common clinical presentation is that of a palpable mass in the chest wall 17 . As with every hernia, a delayed recognition of this injury can prove life-threating, as TDIH can lead to obstruction or strangulation of the intestines 34 .
In the current case report we present a female patient with blunt thoracoabdominal trauma which lead to the development of a right transdiaphragmatic intercostal hernia with the herniation of the right liver lobe through the diaphragm and the fractured 6 th , 7 th and 8 th right ribs. A written informed consent was obtained from the patient and the institutional review board of our hospital approved this report. We also review the relevant literature concerning this rare type of hernia. The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016) 35 .

CASE REPORT
A 60-year-old female visited the Emergency Department after a car accident, in which she was involved as a co-driver in a side collision with another car. On admission, a patent airway and severe respiratory distress were noted. Blood pressure (BP) was 100/40 mmHg and heart rate 89/min. The level of consciousness was normal (Glasgow coma scale score 15). Loss of consciousness or peritraumatic amnesia was not mentioned. During transferring, oxygen and intravenous fluids, both in the form of crystalline and colloidal solutions were given. The patient experienced severe chest pain in both hemithoraxes, as well as in the abdomen, especially in the right hypochondrium. The physical examination revealed; paleness, shortness of breath, tachypnea, left subcutaneous emphysema, bilateral low chest tenderness to palpation, flail chest, reduced breath sounds on both lung bases and dullness to percussion. In the right thoracoabdominal wall a palpable painful mass with an ecchymosis of the overlying skin was palpated, while muscular guarding was detected in the abdomen and especially in the right hypochondrium. She had a known history of coronary heart disease, coronary angioplasty 2 months ago, as well as congenital left hip dislocation.
A central venous catheter in the right internal jugular vein was placed and intravenous fluids and antibiotics (2nd generation cephalosporin) were administered, while a Foley catheter was placed. Given her hemodynamically stability, the patent underwent radiological examination. Chest X-rays revealed fractures of the left clavicle and ribs (6 th , 7 th , 8 th right ribs / 7 th , 8 th , 9 th left ribs), as well as flail thorax, hemothorax bilaterally, left subcutaneous emphysema and swelling of soft tissues of the right lateral thoracoabdominal wall. Other radiographs showed no pathological findings.
Upper and lower abdomen ultrasonography revealed round hypoechoic mass with a capsule measuring 3.7 X 3.9 cm between the visceral surface of the liver and the outer edge of the right colic flexure, while next to it there was an hypoechoic non-capsular hematoma on the lateral abdominal wall. Presence of fluid left pararenal space was detected, while no fluid was revealed in Douglas space. Upper and lower abdomen and posterior peritoneum CT reveled hemothorax bilaterally, but especially on the right, hypoventilation of lower lung fields, left subcutaneous emphysema, rib fractures (6 th , 7 th , 8 th right ribs / 7 th , 8 th , 9 th left ribs), resulting in flail chest. In addition, a large soft tissue hematoma associated to the fractures of the lower thoracic ribs was detected, as well as herniation of hepatic parenchyma and intestinal loops with concomitant hematoma around. A small amount of free intraperitoneal fluid was found perihepatically, left pararenally and in Douglas space, as well as multiple soft tissue injuries of the abdominal wall ( Figure 1).
Taking all of the above into consideration, the patient underwent surgery immediately. An upper midline incision was conducted in order to examine the abdominal viscera. Two fractured ribs were wedged in the right hepatic lobe, which was emerging between them and towards the soft tissues of the abdominal wall, where there was an extensive hematoma. The right hepatic lobe was restored into the peritoneal cavity, its tears were sutured and a "surgicell" pad was placed over them. A right side 3 pleurodesis was carried out, the diaphragmatic rupture was sutured and drainage of the right subhepatic space was placed. The soft tissue hematoma was accessed and drained and Redon type vacuum was placed. The patient was transfused intraoperatively with two units of blood and she recovered without problems.
The postoperative course was uneventful. Hematocrit gradually increased and transaminases level reduced. Although pleural effusions showed a slight increase during the first days, they gradually declined, without drainage and respiratory function improved.
Diuresis was normal during hospitalization, while microscopic hematuria subsided on the 5 th postoperative day. On the 13 th day of hospitalization, the surgical sutures were removed and on the 14 th day a new CT scan revealed a small hernia on the right lateral abdominal wall, with only a small part of hepatic parenchyma protruding. Furthermore, CT scan showed a small right subcapsular hepatic fluid collection, a fluid collection in the fascia of the lateral abdominal wall and bilateral pleural effusion, with accompanying atelectasis of the pulmonary parenchyma. Finally, a subcapsular hematoma of the left kidney was detected, although it was not depicted on the previous CT scan.
On the 17 th postoperative day, the patient was discharged due to her good clinical picture and a reexamination after 10 days, including chest radiography and ultrasonography on the upper abdomen was recommended. Two years after this rare thoracoabdominal trauma patient's course remains uneventful.

DISCUSSION
The term "Transdiaphragmatic Intercostal Hernia" (TDIH), was first used by Cole et al. in 1986 and describes the herniation of abdominal contents through the diaphragm and the thoracic wall defect 1 and it combines transdiaphragmatic and intercostal hernias, as it results from two simultaneous defects, one affecting the diaphragm while another the intercostal space 17 . We used the PubMed database as the source for a literature review and searched for manuscripts published in English. The search terms used were "transdiaphragmatic intercostal hernia". The authors reviewed the search results and decided which of these articles should be incorporated into this study. It is a very rare hernia with only 42 cases having been reported in the literature. 83.72% of the patients were males, with ages between 19 and 85 years old, with an average of 57.47 1,2,4-33 .  This hernia develops following the disruption and separation of intercostal and diaphragmatic muscles 1,17 . Although the mechanism of hernia development varies from spontaneous to systematic diseases and traumas, the most common one is trauma, penetrating, or blunt, as in our case, but can seldom present spontaneously 1,2,4-33 . If certain predisposing factors, such as severe asthma and chronic obstructive pulmonary disease, are present, it may be developed after minor incidents, such as coughing 1,36 . It is most commonly associated with rib fractures and especially with 9th or 10th rib fracture 1 . Review of the literature revealed that the level interspace was the 9th in the majority of cases (56.75%) and that hernias were left-sided in 51.16% of the patients 1,2,4-33 . In the present case, the force exerted on the chest by the collision was so great was so massive, that it caused rib fractures and diaphragmatic rupture in the right hemithorax. Τhrough the discontinuity of the diaphragm and due to fractured ribs the majority of right hepatic lobe protruded into the right hemithorax.
Thorough medical history and physical examination may lead to the diagnosis of TDIH. The most common clinical presentation is that of a palpable mass in the chest wall, as in our patient, that fluctuates during the respiratory cycle 1,17 . Thoracic pain, vomiting or dyspnea may also be manifested 1,17 , while on chest auscultation bowel sounds may be heard 37 . Our patient experienced some of these symptoms. Analysis of the patients' symptoms, found for 30 cases of the literature, and ours, revealed that plethora of symptoms were experienced but mainly pain (67.74%), chest or abdominal, coughing (32.26%) and dyspnea (32.26%), while only one patient (3.23%) was asymptomatic 1,2,4-33 .
Imaging tests can confirm the diagnosis. In particular, chest X-ray can reveal fractures of the ribs, intestinal loops in the thorax and with less sensitivity (17 -46%) diaphragmatic ruptures 17,38 . Thoracoabdominal ultrasonography and CT scan are the confirmatory imaging tests of choice 17 . CT scan can accurately (61-71% sensitivity, 87-100% specificity) detect diaphragmatic rupture by revealing diaphragm discontinuity, visceral herniation, and collar sign (waist-like intestinal constriction) 38 . It can also confirm the extent and contents of the hernia (omentum, liver, colon, small bowel or even gall bladder in order of frequency) 36,39 . In our case, although chest X-ray wasn't able to detect the diaphragmatic rupture nor intestinal content in the thorax, CT revealed the presence of the hernia as well as its content (liver and intestines). Review of the 43 cases, including ours, showed that hernia contained intestines (small or large bowel) in the vast majority of cases and liver was herniating in our patient as well as in 8 more cases (20.93%) 1,2,4-33 . The presentation and thus the diagnosis of TDIH has been reported to be delayed in some cases even for years 1,2,4-33 . A delayed recognition of this injury can prove lifethreating, as TDIH can lead to obstruction or strangulation of the intestines 35 .
The treatment of choice for TDIH is surgery, as hernia is usually symptomatic and cannot be reversed automatically due to the negative intrathoracic pressure that tends to enlarge it 15,17 . 8 Immediate surgery was chosen to be performed in our case as well. The thoracic wall should be first repaired so that the diaphragm can then be fixed at stable attachment points. Large thoracoabdominal incisions that used to be performed in the past tend to be replaced by new techniques, due to the great postoperative pain and the slow mobilization. Nowadays, laparoscopic and endoscopic surgery are increasingly being used to repair uncomplicated intercostal hernias 15 . Video-assisted thoracoscopic surgery could also be performed 39 . Review of the relevant literature reveled that surgical repair was chosen for the treatment in all cases. According to the available data thoracotomy was performed in 11 and laparotomy in 4 cases, while thoracoabdominal approach was chosen in 2 cases. Finally, in 3 more recent cases of 2011, 2012 and 2019 laparoscopic surgery was chosen to be performed 1,2,4-33 .

CONCLUSION
Transdiaphragmatic intercostal hernia is a rare condition, that has been most commonly reported in male patients after trauma, penetrating or blunt. It is frequently manifested with a palpable thoracic mass and pain and can be diagnosed with CT scan in the majotiry of cases. However, sometimes its presentation and thus its diagnosis may be delayed even for years. The indicated treatment is surgery, which nowadays tends to become less invasive through the use of laparoscopic and endoscopic techniques.

Conflict of Interest
The authors declare no competing financial interests or conflicts of interest.