Lung Hernias of the Chest Wall
Thomas W. Shields
Lung Herniations
The occurrence of a lung hernia was first reported by Roland in 1499,25 and a classification of these hernias was initially suggested by Morel-Lavalle.17 The classification was simple: congenital or acquired. The latter hernias were subclassified as spontaneous–pathologic or traumatic (the latter being the more common type). An up-to-date classification is listed in Table 44-1.
Congenital Hernias
Congenital hernias are most often found in the supraclavicular space and infrequently at one of the anterior costochondral junctions or laterally in an intercostal space owing to the lack of development of an intercostal muscle. Weissberg and Refaely35 recorded two congenital hernias in the supraclavicular fossa, neither of which required repair. These authors also recorded two congenital intercostal hernias, both of which were symptomatic and were surgically repaired. In this respect, the congenital intercostal hernias are similar to the spontaneous and traumatic lung hernias, because most of the latter two types require surgical intervention.
Supraclavicular Herniation
Occasionally a supraclavicular lung hernia will become symptomatic and repair should be undertaken. A transcervical approach has been reported by Victor and colleagues.34 However, there is a greater risk of recurrence with this approach and transthoracic access is now preferred, especially since the development of video-assisted thoracic surgery (VATS). It is noted that in the presence of a supraclavicular lung hernia, Sibson’s fascia may or may not be intact. When it is intact, a hernia sac is present and this must be dissected free and the excess fascia and adjacent fatty tissues must be removed before the repair of the cervical defect. When fascia is not intact and no hernia sac is present, only closure of the defect by the use of sutures or the use of a prosthetic patch after reduction of the hernia is indicated. Jheon and associates14 were among the first groups to report a transthoracic VATS repair. Subsequently Rahman and coworkers22 reported the sequential repair of symptomatic bilateral cervical hernias by a standard transthoracic approach.
Intercostal Congenital Lung Hernias
Although most supraclavicular lung hernias do not require surgical intervention, almost all congenital intercostal hernias require surgical repair, as recorded by Weissberg and Refaely.22 Of interest is that most congenital intercostal hernias do not become symptomatic until middle or late adulthood.
Traumatic
Blunt Trauma
Traumatic lung hernias may occur after nontraumatic penetrating injuries such as surgical incision; this type was considered the more common of the two types of noncongenital herniations, as reported by Forty and Wells.8 However, it now appears that blunt trauma occurring during motor vehicle crashes to patients with shoulder harness seatbelt restraints (i.e., three straps) in place is the more common cause. Arajävi and colleagues2 have described the abdominal injuries sustained by seatbelt users, and Arajävi and Santavirta1 have evaluated chest injuries with fatal outcomes in such individuals; the cause of death was most often unrelated to the seatbelt itself. Lung contusions and lung lacerations occurred, but the incidences were low. Sternal fractures were the most common fractures, but rib fractures were not infrequent. The incidence and site of the rib fractures were influenced by the side of the car in which the individual was sitting as well as the direction (i.e., right to left or left to right) of the shoulder seatbelt harness. In 14 drivers sitting on the left side with the strap passing from the left shoulder to the right side of the lower horizontal belt, fractures of the right rib cage (most often in the costochondral junction area) were sustained in 78.6%; fractures located in the left rib cage were sustained in only 28.6%. In 29 passengers sitting on the right side with the strap passing from right to left, the incidence of the fractures was reversed: 75.7% were in the left chest cage and 48.3% in the right chest cage. May and associates16 noted lung herniation at the site of the “seatbelt fractures” and considered this another aspect of the “seatbelt syndrome,” so named by Garrett and Braunstein.9 As noted, the site of the rib fractures is often along the costochondrosternal junction, but they may occur in other areas of the chest wall as well (Fig. 44-1). The lung herniation may be identified early, or its identification may be delayed for months to years.
As more of these blunt injuries to the chest have been seen in surviving patients, it has become apparent that the major site of the “seatbelt” injuries that subsequently result in lung herniations are located in the parasternal area (Fig. 44-2). May and colleagues16 were among the first to point out the parasternal injury. This injury was further discussed by Jacka and Luison13
as well as by Reardon and associates.23 The incidence of such injuries has decreased as the result of the presence of air bags in the front compartment in most modern cars. However, air bags are lacking in the back seat area, so that in major accidents an individual in the back using a seat belt may suffer a chest wall fracture, as noted by Beckert and colleagues.3
as well as by Reardon and associates.23 The incidence of such injuries has decreased as the result of the presence of air bags in the front compartment in most modern cars. However, air bags are lacking in the back seat area, so that in major accidents an individual in the back using a seat belt may suffer a chest wall fracture, as noted by Beckert and colleagues.3
Table 44-1 Lung Hernias of the Chest Wall | ||||||||
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Diagnosis
A lung herniation may or may not be symptomatic, but it most often presents as a tender subcutaneous mass that may enlarge on straining or during an episode of coughing. A Valsalva maneuver will usually enlarge the soft tissue mass. The diagnosis should be confirmed by the appropriate radiographic examination of the chest. This may include standard and oblique radiographs; at times, computed tomography (CT) may be helpful, as suggested by Tamburro and colleagues.31 Weissberg and Refaely35 believe that the most accurate method may be the use of spiral CT while the patient carries out a Valsalva maneuver, as suggested by Hauser and colleagues.12
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