Staged Reconstruction With a Reverse Latissimus Dorsi Flap for Late-Onset Lumbar Surgical Site Infection in a Previously Irradiated Field: A Case Report.

Surgical site infection (SSI) after spinal instrumentation surgery remains a challenging complication, particularly in patients with a history of radiotherapy. Radiation-associated skin and soft tissue injuries cause long-lasting impairment of vascularity and regenerative capacity, significantly compromising wound healing and infection control. When SSI occurs in radiation-affected tissue, wound closure becomes difficult, requiring complex reconstructive surgery. A 73-year-old man who had previously received radiotherapy to the lumbar region for malignant lymphoma at the age of 37 (in 1989) developed a late-onset lumbar SSI seven years after posterior lumbar interbody fusion at L3/4. Initial surgical debridement followed by primary wound closure failed, leading to wound dehiscence two weeks postoperatively. Considering the impaired biological regenerative activity of the irradiated tissues, repeated primary closure was avoided. Instead, staged management consisting of extensive debridement, negative pressure wound therapy (NPWT) with continuous local irrigation, and definitive reconstruction using a reverse latissimus dorsi musculocutaneous flap was performed. Although flap coverage was insufficient for the lower lumbar to sacral region, continued NPWT promoted tissue granulation, allowing successful split-thickness skin grafting. Complete wound closure was ultimately achieved. SSI in irradiated tissue may reflect impaired regenerative capacity in addition to the infectious process itself. A reverse latissimus dorsi musculocutaneous flap combined with NPWT and skin grafting enabled successful closure of a large tissue defect of the lumbar spine without infection recurrence at six-month follow-up.