Myelomeningocele Defects Reconstruction With Various Types of Keystone Flaps: An Algorithmic Approach Based on Defect Shape.

The keystone flap has become an established option that has been utilized recently to close significant myelomeningocele defects. Although the keystone flaps can be adapted to repair myelomeningocele defects of different sizes, the shape of the defect is also an essential factor to consider. In this study, the authors proposed an algorithmic approach for reconstructing significant meningomyelocele defects utilizing different types of keystone flaps based on the shape of the resulting defect. From September 2016 to March 2022, the authors retrospectively reviewed the medical records of 28 patients with meningomyelocele who underwent repair with the keystone flaps. The mean age was 28 days (3 days to 4.5 months). Twenty-one meningomyelocele defects were in the lumbosacral (75%) and 7 in the thoracolumbar regions (25%). The defect sizes ranged from 3.5×5 cm (area, 13.4 cm 2 ) to 9×7 cm (area, 49.5 cm 2 ), with an average of 26.2 cm 2 . Ten meningomyelocele defects were a vertically oriented oval shape, 16 defects were a transversely oriented oval shape, and 2 defects were circular. In addition, unilateral keystone flap was used in 7.1% of the patients (2 patients), bilateral keystone flap in 28.6% (8 patients), and rotation advancement keystone flaps in 64.3% (18 patients). According to these findings, an algorithm was created based on the defect shape. This algorithmic approach is used as a decision-making guide to select the correct type of keystone flaps to repair myelomeningocele according to the defect shape.