Diaphragmatic Hernia

The impetus for this post was the referral  to our Trauma Service of a middle aged gentlemen approximately 2 years s/p high speed MVC who initially presented to the ED with complaints of vague, intermittent RUQ pain.  A plain chest radiograph obtained at the time was significant for what appeared to be a right lower lobe lung mass.  Subsequent CT imaging revealed this to be a multisegmental herniation of the liver through an approximately 10cm right diaphragmatic defect.  There was no mention of a diaphragm injury, and we therefore considered this a delayed presentation consistent with a diaphragmatic hernia.  The purposes of this post are to review the management of sub-acute or chronic diaphragmatic injury and hernia.

The incidence of sub-acute diaphragmatic injury or post traumatic diaphragmatic hernia is unknown.  A portion of patients may remain asymptomatic and therefore never come to medical attention.  Alternatively, some portion of this asymptomatic cohort will have their hernia discovered incidentally on imaging evaluating other complaints at a later time.  If symptoms are present, they may be vague and nonspecific or be consistent with obstruction, incarceration or strangulation of the abdominal contents herniating into the chest. 

Chronic diaphragmatic hernias may be repaired either transabdominally or transthoracically.  The traditional teaching has been that chronic, large diaphragmatic hernias are better approached transthoracically.  This facilitates direct exposure of intrathoracic adhesions as well as avoidance of adhesions from a prior trauma laparotomy, as the case may be.  In certain instances, a combined approach may be necessary.  The operation can be accomplished either via a posterolateral thoracotomy or thoracoscopically, depending on the nature of the hernia, the surgeon’s experience, skill and preference.  Recommendations favor the open approach for defects greater than 10cm.

The repair itself can be fashioned either primarily or with prosthetic mesh.   All adhesions must be lysed, and the hernia reduced.  After which the edges should be approximated.  In contrast to acute diaphragmatic injury, in a chronic defect, the edges may be retracted or atrophied and primary apposition may not be possible.  If it is, allis clamps may be used to hold the edges in place while the defect is closed using an O or #1 non absorbable suture.  If there is undue tension on the closure or the edges cannot be reapproximated, PTFE (Gore-tex®) mesh may be used.  Prosthetic mesh is most often required for defects greater than 6-8 cm.  The patch is anchored to the edges of the defect in a running fashion using O nonabsorbable suture.  The patch should be trimmed such that redundancy is minimized and an anatomic diaphragmatic contour is preserved.  If there is inadequate tissue laterally, the mesh can be secured using interrupted stitches around the ribs at the level of the native diaphragm.  Autologous tissue transfer flaps have also been described, including latissimus dorsi, rectus, or external oblique, primarily in pediatric populations.

from Andrew Popoff, M.D.

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