Challenging the Dogma of Dead Space Obliteration With Muscle Flaps in Deep Spinal Surgical Site Infections

Abstract

Background: A deep surgical site infection (SSI) after spinal surgery is a serious complication. The defect formed is often a complex 3-dimensional dead space due to tissue loss, frequently containing spinal hardware. Traditionally, obliteration of that dead space is performed with the use of muscle flaps. We challenge this dogma in reconstructive surgery by using the medial dorsal intercostal artery perforator (MDICAP) flap as an alternative in the reconstruction. It adheres to the concept of replacing "like with like," as there are no muscles at the posterior midline.

Methods: A retrospective study was performed of a cohort of 18 patients with deep SSI and a posterior midline defect after spinal surgery who received reconstruction with the MDICAP flap. A review of postoperative imaging with focus on dead space was performed.

Results: All patients had satisfactory functional and aesthetic outcomes. No patients had a recurrent deep SSI during follow-up (average 64 mo, range 3-384 mo). In the 16 patients who had postoperative imaging performed, dead space was not present at the flaps' recipient site.

Conclusions: The MDICAP flap is a good alternative to muscle flaps in reconstructive surgery for complex posterior midline defects caused by a deep SSI after spinal surgery. Postoperative imaging showed no dead space with the use of MDICAP flaps. All patients had an uneventful postoperative course with no recurrent infections. This challenges the dogmata of (1) the need for muscle flaps in such reconstruction and (2) the obligate need for dead space obliteration at the time of operation.

Fig. 1.

Principles of posterior trunk reconstruction, as formulated by Ramasastry et al.

Fig. 2.

MDICAP flap marked on the skin before dissection and harvest (patient 13).

Fig. 3.

Intraoperative view showing the complex 3-dimensional wound cavity in patient 13. Spinal hardware is present lateral to the spine on each side.

Fig. 4.

The MDICAP flap has been dissected in patient 13. Picture taken before transposition.

Fig. 5.

Flap to be sutured over suction drain in patient 13. The dead space is not obliterated by the thin flap.

Fig. 6.

This figure shows clearly that the perforator flap does not obliterate dead space in patient 13.

Fig. 7.

Patient 13 directly after removing surgical drapes postoperatively. The MDICAP flap is stapled in line with other subcutaneous tissue. It is not “sunken”; therefore, dead space is present.

Fig. 8.

Digital photography showing clinical result at follow-up consultation of patient 13, who did not receive postoperative wound stabilization with the VAC system.

Fig. 9.

Three-dimensional reconstruction of CT scan depicting the flap “sunken” into the wound cavity in patient 13, in line with clinical findings seen.

Fig. 10.

CT scan of patient 13 performed 4 years postoperatively. The scan is showing the reconstructed area in the sagittal plane. The flap is seen posterior to the osteosynthesis material and fibula graft. No dead space could be detected on the CT scan, which showed only minimal artifacts from hardware.

Fig. 11.

CT scan showing the reconstructed area in the axial plane in patient 13. The flap is sunken in and appears to be settled deeper than the surrounding subcutaneous tissue in the wound cavity. There is no dead space, and minimal artifacts from hardware.

Fig. 12.

Sagittal T2 short tau inversion recovery sequence MRI from patient 13 3 years after the operation. In the sagittal plane, no dead space can be seen. There are minimal artifacts from spinal hardware.

Fig. 13.

Axial T2-weighted MRI image from patient 13. There are no signs of dead space, and the flap is filling the wound cavity.