Repair of Congenital diaphragmatic hernia with large defect with abdominal muscular patch repair-

Introduction

The repair of large congenital diaphragmatic hernia (CDH) defects is technically challenging and is plagued by a significant risk of recurrence. These large defects are typically repaired using either synthetic or modified biologic patches. Given the normal expansion of the thorax during growth and development, it is not surprising that there is a high rate of recurrence in cases in which large defects are spanned with a patch. The rate of recurrence in some series has been reported to be in excess of 40%.

Technique

All repairs in seven cases were performed using an open technique. The diaphragm was approached through a generous, subcostal incision. To preserve the option of a split abdominal muscle flap, the fascial incision was made 2 to 3 fingerbreadths below the costal margin. After reduction of the herniated viscera, the peritoneum overlying the posterior margin of the diaphragm was incised. If feasible, a primary diaphragmatic muscular closure was performed using pledgeted nonabsorbable sutures. Thoracostomy tubes were variably placed. In infants in whom a primary repair could not be accomplished, a prosthetic patch or split abdominal wall muscle flap closure was performed. In either case, as much of the defect as possible was closed primarily using pledgeted sutures. In the case of a patch repairs, the patch was tailored to assure adequate redundancy to avoid tension and allow growth. The patch was fixed to the margins of the diaphragm if there was sufficient tissue or in pericostal fashion if there was none.

In brief, a muscle flap is created by separating the internal oblique and transversalis muscles away from the external oblique muscle. The plane between these muscles is avascular, and this separation is easily accomplished using finger dissection. The internal oblique and transversalis muscles are folded posteriorly and fixed to the 12th rib posteriorly and to the flank musculature laterally. The rectus abdominus and external oblique are then used to close the abdomen.

This technique holds the appeal of using growing autologous tissue for the repair. Logically, this should be associated with a decreased risk of recurrence. Although this technique was initially described in 1962, there is limited literature on its use. This muscle flap has been commonly used by us in 7 cases with apparently good results. We therefore hypothesized that use of the split abdominal wall muscle flap for large diaphragmatic defects would be associated with a lower recurrence rate than patch repair.

The management of patients with CDH in our newborn intensive care unit has been relatively consistent in all seven cases. In brief, this strategy focuses on the avoidance of barotrauma with the use of permissive hypercapnea and reasonable oxygenation goals anticipating shunting. Operative repair is delayed until pulmonary hypertension has resolved as demonstrated using echocardiography and decreased ventilator requirements.

Although there is a large volume of literature regarding management of CDH, most focuses on the consequences of pulmonary hypoplasia, management of pulmonary hypertension, and lung-protective strategies. The literature specifically addressing operative strategies to reduce the risk of recurrence is limited. The current series demonstrates that most (potentially all) congenital diaphragmatic defects can be fixed using autologous tissue if a split abdominal wall muscle flap closure strategy is used.

Reasons for recurrences can be addressed

Given the marked increase in the size of the thorax during growth and development, this is not surprising. Efforts to decrease recurrences have focused chiefly on the use of biologic matrix patches with the hope that tissue ingrowth would prevent recurrence, length of stay or inability to close the abdomen was associated with increased recurrence.

Two specific operative strategies with synthetic mesh have been reported to decrease the risk of recurrent herniation. Advocated for fashioning a cone-shaped patch for use in the repair.

The technique of split abdominal wall muscle flaps for repair of large diaphragmatic defects is more than 40 years old.

at least 88% patients could undergo repair with an autologous tissue repair (primary closure or split abdominal wall muscle flap closure) yielding an overall very low risk of recurrence.

The split abdominal muscle flap allows repair of even large diaphragmatic defects. The technique is straightforward and can be used even if a CDH repair is done while the infant is onventillator in NICU. The recurrence risk is comparable with that of primary repair and significantly less than most series report for patch repairs.