I reached out to the senior auditor at United Healthcare for the documentation requirements for complex repairs and this is the response I received:
Complex Repair
Complex repair includes the repair of wounds that, in addition to the requirements for intermediate repair, require at least one of the following: a) exposure of bone, cartilage, tendon or named neurovascular structure; b) debridement of wound edges (e.g., traumatic lacerations or avulsions); c) extensive undermining (defined as a distance greater than or equal to the maximum width of the defect, measured perpendicular to the closure line along at least one entire edge of the defect); d) involvement of free margins of the helical rim, vermilion border, or nostril rim; or e) placement of retention sutures. Necessary preparation includes creation of a limited defect for repairs or the debridement of complicated lacerations or avulsions. Complex repair does not include excision of benign (11400-11446) or malignant (11600-11646) lesions, excisional preparation of a wound bed (15002-15005) or debridement of an open fracture or open dislocation.
Intermediate Repair
Intermediate repair includes the repair of wounds that requires layered closure of one or more of the deeper layers of subcutaneous tissue and in which superficial (non-muscle) fascia is required in addition to the skin (epidural and dermal) closure. Intermediate repair includes limited undermining, which is defined as a distance less than the maximum width of the defect, measured perpendicular to the closure line, along at least one entire edge of the defect. Intermediate repair may also be reported for single-layer closure of heavily contaminated wounds that have required extensive cleaning or removal of particulate matter.