The abdominal approach for diaphragmatic plication is appropriate in properly selected patients. Open transabdominal plication has been described for unilateral or bilateral diaphragmatic eventration or paralysis in children,¹ but very few data are available on the results of open transabdominal plication in adults. Laparoscopic diaphragm plication was initially described by Hüttl et al. in a report of three patients.² We reported our experience with 25 patients demonstrating that the laparoscopic approach to diaphragm plication results in significant short- and mid-term improvements in symptoms, quality of life, and pulmonary function tests (PFTs) in patients with hemidiaphragm paralysis or eventration.³

The choice of access for diaphragmatic plication is primarily guided by surgeon experience and preference. The minimally invasive approach is preferred over an open approach, since it is associated with less morbidity, although no direct comparisons between open and minimally invasive plication have been reported in the literature. As a general rule, the anterior portion of the hemidiaphragm is easier to access via the abdomen, whereas the posterior portion is more approachable through the chest. Finally, regardless of approach, proper patient selection, safety, and tight imbrication of the entire hemidiaphragm are essential.

The theoretical advantages of a transabdominal approach in comparison with a transthoracic approach are (a) easy intraoperative positioning (supine vs. lateral decubitus), (b) selective ventilation is unnecessary, (c) the abdominal cavity offers ample operating room, (d) there is direct visualization of the intraabdominal organs which reduces the risk of injury during imbrication, and (e) there is less postoperative pain. Disadvantages of transabdominal plication include difficult visualization of the posterior portion of the hemidiaphragm, potential splenic or liver laceration, and technical challenges in centrally obese patients.

The potential candidate for diaphragmatic plication must have dyspnea that cannot be solely attributed to another process (e.g., poorly controlled primary lung or heart disease) and must have an elevated hemidiaphragm on a posteroanterior and lateral (PA/LAT chest x-ray. Since the only goal of diaphragm plication is to treat dyspnea; operative intervention is indicated exclusively for symptomatic patients. An elevated hemidiaphragm or paradoxical motion per se do not warrant surgery in the absence of significant dyspnea.

Relative contraindications to laparoscopic diaphragm plication are previous extensive abdominal surgery, BMI >35 for females and BMI >30 to 35 for males, and certain neuromuscular disorders. Ideally, morbidly obese patients should be evaluated for medical or surgical bariatric treatment prior to plication, since dyspnea may improve after significant weight loss and a plication may no longer be warranted. Any type of plication is challenging in the morbidly obese patient: the degree of plication may be compromised due to technical difficulties, the relief of dyspnea may be limited, and complications are likely. Patients with neuromuscular disorders should be approached with extreme caution; the symptomatic improvement is moderate at best, and complications are common. An individualized multidisciplinary approach is necessary to decide on a plication in patients with morbid obesity or neuromuscular disorders.

Clinical Evaluation

The diagnosis of symptomatic hemidiaphragm paralysis or eventration is primarily clinical, and relies mostly on history, chest x-ray, and the physician’s clinical acuity.

The evaluation of a symptomatic patient with diaphragmatic paralysis or eventration should include an objective assessment of dyspnea, physical examination, PFTs, and imaging studies.

Careful history taking about the duration and progression of dyspnea and orthopnea is critical. Any additional causes of dyspnea (e.g., morbid obesity, primary lung disease, heart failure) should be investigated and corrected if possible, since dyspnea secondary to diaphragmatic paralysis or eventration is mainly a diagnosis of exclusion.

All patients with dyspnea secondary to an elevated hemidiaphragm eventration should fill out a standardized respiratory questionnaire to more objectively evaluate the severity of their symptoms and to assess the response to treatment.

Pulmonary Function Tests

PFTs provide certain objectivity to the assessment of dyspneic patients with an elevated hemidiaphragm; however, PFTs are imprecise and do not correlate well with severity of dyspnea or response to plication. Since diaphragm dysfunction reduces the compliance of the chest wall, a restrictive pattern (i.e., low forced vital capacity [FVC] and forced expiratory volume in 1 second [FEV₁]) is often seen.⁴

The diaphragm is a critical mediator of inspiration; therefore, assessing inspiratory PFT parameters (e.g., maximum forced inspiratory flow [FIFmax]) is important.

In addition, FVC should be assessed in the upright and supine position. Supine FVC in healthy individuals can decrease up to 20% from upright values, and supine lung volumes may decrease by 20% to 50% in patients with diaphragmatic eventration or paralysis.

Imaging Studies

Chest x-ray

On a standard full-inspiration PA/LAT chest x-ray, the right hemidiaphragm is normally 1 to 2 cm higher than the left. Hemidiaphragm elevation can be a sign of diaphragmatic paralysis or paralysis; however, this is a nonspecific finding since a variety of pulmonary, pleural, and subdiaphragmatic processes can also cause elevation of the hemidiaphragm. Consequently, further studies may be needed if an elevated hemidiaphragm is noted on a chest x-ray in the presence of dyspnea.

Fluoroscopic Sniff Test

The clinical value of a sniff test is limited in the presence of an elevated diaphragm and dyspnea. The principal role of the sniff test is to help discern the etiology of dyspnea in patients with a less evident primary cause of dyspnea.

During fluoroscopy, patients are instructed to sniff, and diaphragmatic excursion is assessed. Normally, the diaphragm moves caudally. In patients with hemidiaphragmatic paralysis, the diaphragm may (paradoxically) move cranially. Patients with diaphragmatic eventration, however, may also exhibit passive upward movement of the diaphragm when sniffing.

Fluoroscopy findings should be interpreted with caution. First, about 6% of normal individuals exhibit paradoxical motion on fluoroscopy; to increase the specificity of this study, at least 2 cm of paradoxical motion should be noticed. Second, a paralyzed or eventrated hemidiaphragm may move very little or not at all, without paradoxical motion, making the interpretation of the sniff test and the distinction between paralysis and eventration even more challenging.⁴

Computed Tomography

The principal utility of computed tomography (CT) scans is to exclude the presence of a cervical or intrathoracic tumor as the cause of phrenic nerve paralysis or to evaluate the possibility of a subphrenic process as the cause of hemidiaphragm elevation. However, a CT scan is not routinely required if the clinical suspicion of an alternate process is low.