Plication of the Diaphragm

Plication of the diaphragm is a surgical procedure that has been performed since the 1920s for the treatment of diaphragmatic paralysis. ^[1] Diaphragmatic paralysis is a serious problem for individuals suffering from the respiratory abnormalities, reduced energy levels, and sleep disturbances that are commonly associated with the disorder. The inability of the lung to expand fully in patients with diaphragmatic paralysis also makes these individuals more susceptible to pleural effusions, pneumonia, and atelectasis.

The goal of diaphragm plication is to flatten the dome of the diaphragm, providing the lung with greater volume for expansion. Since its original description, diaphragm plication has been performed with numerous modifications, including the minimally invasive video-assisted thoracic surgery (VATS) approach. ^{[2, 3]} Laparoscopic robot-assisted diaphragm plication has also been reported. ^[4] Diaphragm plication surgery using both transabdominal and transthoracic approaches has been performed in both children and adults.

Alternatives to diaphragm plication for the successful treatment of diaphragmatic paralysis include diaphragm pacing and phrenic nerve grafting. ^[5] Recently, there has been progress in the area of phrenic nerve surgery, which repairs injuries to the phrenic nerve using nerve grafts or nerve transfers. ^{[6, 7]} Alternatively, patients with bilateral diaphragmatic paralysis from spinal cord injury may be better served with a diaphragm pacemaker to restore function to the diaphragm. Patients with diaphragmatic paralysis now have options for treatment, including both phrenic nerve grafting and diaphragm plication.

Diaphragm plication is appropriate for pediatric and adult patients with symptomatic diaphragmatic paralysis who have failed conservative management and have not exhibited spontaneous signs of improvement. There are instances when diaphragmatic paralysis is temporary; over the course of weeks to months, the injury may reverse itself, ultimately resulting in a return of normal diaphragm function. However, if there are no signs of spontaneous improvement over a 6- to 12-month period, then the injury is likely permanent.

A proper assessment of the muscle paralysis will determine if diaphragm plication is the most appropriate treatment option. Typically, this applies to patients with severe neuromuscular injuries who demonstrate complete loss of diaphragm motor units, making reinnervation difficult or impossible. Furthermore, complete loss of diaphragmatic innervation from the phrenic nerve will prevent successful diaphragm pacing. A comprehensive electrodiagnostic assessment of the phrenic nerve and diaphragm will usually provide the necessary information.

Patients with diaphragmatic paralysis are not candidates for diaphragm plication surgery if the injury is thought to be temporary or they are exhibiting signs of spontaneous improvement. Furthermore, diaphragm plication is contraindicated if the individual has significant comorbidities that would increase risk. Active or recurrent pulmonary infections, chronic lung disorders, and severe heart disease could be associated also be associated with unacceptable risks if diaphragm plication surgery was attempted.

Relevant Anatomy

The relevant anatomy consists of the right and left phrenic nerve and respective hemidiaphragm on both sides of the body. Each phrenic nerve leaves the spinal cord at the cervical level in the neck (C3-5), runs down the neck on the scalene muscle, and dives under the clavicle into the chest cavity.

In the chest cavity, each nerve runs between the heart and lung, entering the diaphragm towards the medial aspect of the muscle and dividing into several branches to provide nerve impulses to the various parts of the muscle. The intramuscular phrenic nerve has some variability; however, it is generally described as having several large branches that innervate segments of the diaphragm with an overlapping “net” of smaller nerve fibers.

The diaphragm is a broad flat muscle that effectively acts as both the barrier between the thoracic and abdominal cavities, and the primary muscle of inspiration. When the diaphragm muscle contracts, it descends, permitting the lungs to expand passively.

The vital role of the diaphragm in respiration is obvious, though its contribution varies based on position and sleep. The diaphragm is responsible for 56% of the tidal volume in the awake, supine patient and up to 81% during periods of deep sleep.

Outcomes are generally favorable with good long-term prognosis. In a study of 17 patients, Graham et al demonstrated that transthoracic plication resulted in improvement in symptoms and pulmonary function tests. ^[8] Specifically, the forced vital capacity improved up to 18%. In a study of 15 patients with an average follow-up of 10 years, Higgs et al also demonstrated durable improvements in dyspnea scores, patient satisfaction, and pulmonary function tests. ^[9] Specifically, forced expiratory volume improved 15.4%. In a study of 41 patients using thoracoscopic techniques, Freeman et al demonstrated improvement in forced vital capacity of 17% and forced expiratory volume of 21%. ^[10]