Case studyImpact of surgical site infection and surgical debridement on lumbar arthrodesis: A single-institution analysis of incidence and risk factors
Introduction
Advances in surgical techniques and patient selection have resulted in improved outcomes following spine fusion. However, these procedures still require the introduction of foreign hardware and significant tissue dissection and manipulation of native anatomy. As a result, spine fusion patients can experience significant postoperative pain and other less common complications including cerebrospinal fluid (CSF) leak, hardware failure, hematoma, and nerve damage [9]. Surgical site infection is another uncommon but morbid complication for lumbar spine fusion, and has an incidence of 0.3%-9%, depending on a multitude of factors including preoperative diagnosis, type of operation, and patient demographics [1], [11], [17], [21], [22], [23]. Following diagnosis of postoperative wound infection, patients typically undergo wound irrigation and debridement with removal of graft bone. Postoperatively, patients are then placed on oral or intravenous (IV) antibiotics and then monitored for resolution of infection [14].
Infection and debridement surgery has significant short-term and long-term sequelae including increased hospital stay, 30-day readmission, decreased quality of life and decreased satisfaction with the index procedure [7], [19], [26]. However, there is no consensus on the impact of irrigation and debridement or wound infection on long-term fusion rates. There has been previous laboratory data suggesting inflammatory markers associated with infection are beneficial in achieving bone growth [13], [25], [28]. However, other groups have not shown this association, and in fact, have suggested that the inflammatory response is detrimental for achieving successful arthrodesis [8]. Therefore, the authors designed a retrospective review to assess the rate of arthrodesis following irrigation and debridement following lumbar spine fusion. By doing so, the authors hope to better characterize the rate of arthrodesis following surgical debridement for wound infection, and identify any pre-, peri-, and post-operative factors predictive of either arthrodesis or pseudoarthrosis.
Section snippets
Materials and methods
Patients who were: 1) age ⩾18 years at time of surgery, 2) had lumbar spine fusion between 2008 and 2014, 3) debridement of deep lumbar SSI, and 4) lumbar spine anterior and posterior (AP), lateral flexion/extension X-rays and computed tomography (CT) at 12 months or greater postoperatively were retrospectively included for statistical analysis. Institutional Review Board (IRB) approval was obtained prior to data collection and chart review.
Demographic data including age, sex, race, and body
Patient characteristics
In total, 25 patients (15 female, 10 male) involving 58 spinal levels met inclusion criteria and were reviewed in this study. From 2008 to 2014, an additional 8 patients underwent lumbar spine fusion complicated by infection and wound debridement, but did not meet inclusion criteria due to lack of imaging follow-up. The mean age and BMI were 63.2 ± 12.6 years and 31.6 ± 7.5 kg/m2, respectively. Fifteen (60%) patients were obese (BMI >30.0 kg/m2), 2 (8.0%) were active smokers, 4 (16.0%) had CAD, 19
Discussion
The goals of spinal surgery ultimately remain in achieving adequate decompression of neural elements and achievement of successful arthrodesis through the incorporation of spinal instrumentation. Despite appropriate pre-incisional antibiotics and skin preparation, infection remains a well-known complication of spinal surgery. Current literature estimates the rate of spine surgery wound infection between 0.3% and 9%, depending on risk factors including diabetes, smoking, obesity, malnutrition,
Conclusion
Post-operative infection results in a high rate of pseudoarthrosis in patients undergoing lumbar fusion surgery complicated by SSI requiring debridement. The use of interbody cage during initial fusion was significantly associated with higher rate of arthrodesis likely from the retained and protected bone graft not removed at debridement as well as increased stability. Despite post-operative infection, when interbody grafts are placed there is a high rate of fusion.
Disclosures
No funding of any kind was received for this manuscript.
Sources of support
None.
Conflicts of interest
None.
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