Introduction. Deep soft tissue wounds have a significant volume of dead space that often delays healing. Negative pressure wound therapy with instillation and dwell time (NPWTi-d) used as an irrigation channel to manage deep cavity wounds with a tunneled opening has yet to be described to the authors' knowledge. Case Report. The patient presented with pain and swelling of the left foot along with fever, elevated inflammatory markers, and signs of infection. Antibiotics were initially provided. Surgical debridement with a minimally invasive incision revealed a deep midfoot plantar abscess and resulted in a 2.2 cm wound with a cavity extending 5 cm from the second to fourth metatarsophalangeal joints, initially managed with topical dressings. At postoperative day 5, NPWTi-d (-125 mm Hg) with instillation of betadine-polyhexanide solution and dwell time of 10 minutes was initiated and provided twice weekly for 2 weeks. Clinicians created a foam dressing irrigation channel that enabled cleansing of the entire wound and reduced the volume of dead space within the cavity. A hydrocolloid dressing was used to protect wound edges. The type of NPWT system was changed as healing progressed. No repeat surgical debridement was required, and inflammatory markers down trended over the course of the 3-week hospital admission. The deep cavity wound demonstrated good progress with healing, and eventually healed completely by 2 months from initial surgical debridement. Conclusions. In a deep cavity wound with a small tunneled opening, NPWTi-d used as an irrigation channel is effective in reducing dead space and removing debris, in addition to avoiding the need for multiple surgical debridements and minimizing dressing change frequency.