Complex sentence: The area of the defect is evaluated and marked laterally mid-line, and (marked) positioning sutures are positioned (one, each) at the proximal and distal ends of the area of urethra closest to the bisection points.
Split into simpler sentences: The area of the defect is evaluated and marked both mid-line (laterally), and at the distal and proximal borders (transversely). Marked/labeled positioning sutures are secured (one, each) at the proximal and distal ends of the mid-line area of urethra closest to the bisection points.