The Influence of Pelvic Incidence and Lumbar Lordosis Mismatch on Development of Symptomatic Adjacent Level Disease Following Single-Level Transforaminal Lumbar Interbody Fusion.

BACKGROUND: Annual incidence of symptomatic adjacent level disease (ALD) following lumbar fusion surgery ranges from 0.6% to 3.9% per year. Sagittal malalignment may contribute to the development of ALD. OBJECTIVE: To describe the relationship between pelvic incidence-lumbar lordosis (PI-LL) mismatch and the development of symptomatic ALD requiring revision surgery following single-level transforaminal lumbar interbody fusion for degenerative lumbar spondylosis and/or low-grade spondylolisthesis. METHODS: All patients who underwent a single-level transforaminal lumbar interbody fusion at either L4/5 or L5/S1 between July 2006 and December 2012 were analyzed for pre- and postoperative spinopelvic parameters. Using univariate and logistic regression analysis, we compared the spinopelvic parameters of those patients who required revision surgery against those patients who did not develop symptomatic ALD. We calculated the predictive value of PI-LL mismatch. RESULTS: One hundred fifty-nine patients met the inclusion criteria. The results noted that, for a 1° increase in PI-LL mismatch (preop and postop), the odds of developing ALD requiring surgery increased by 1.3 and 1.4 fold, respectively, which were statistically significant increases. Based on our analysis, a PI-LL mismatch of >11° had a positive predictive value of 75% for the development of symptomatic ALD requiring revision surgery. CONCLUSIONS: A high PI-LL mismatch is strongly associated with the development of symptomatic ALD requiring revision lumbar spine surgery. The development of ALD may represent a global disease process as opposed to a focal condition. Spine surgeons may wish to consider assessment of spinopelvic parameters in the evaluation of degenerative lumbar spine pathology.

Preoperative prealbumin level as a risk factor for surgical site infection following elective spine surgery.

BACKGROUND: Nutritional status is a critical factor in patient outcomes in a variety of medical contexts. In the surgical fields, there is substantial evidence suggesting that clinical outcomes including infection risk and surgical efficacy may be affected by preoperative nutritional status. The purpose of this study is to evaluate preoperative serum prealbumin levels, the currently preferred serum biomarker of nutritional deficiency, in relation to the risk of developing a surgical site infection. METHODS: A retrospective case-control series was conducted comparing prospectively collected preadmission serum prealbumin levels to the risk for surgical site infection following elective spine surgery. The analysis was conducted under an approved institutional quality assurance protocol. Patients were identified by querying the department billing codes for deep wound washouts over a 3-year period. A cohort of 32 patients with preoperative prealbumin levels who underwent spine surgery complicated by postoperative deep tissue infection was identified. This was compared against a case-control cohort of 74 patients who underwent spine surgery and did not experience postoperative infection. Clinical variables included demographic information, body mass index, smoking, diabetes, steroid use, length of the procedure, and length of hospital stay. The data were analyzed using multivariate Cox regression. RESULTS: Two variables: Preoperative prealbumin < 20 and diabetes were both statistically significant predictors for the risk of developing a postoperative infection with hazard ratios of 2.12 (95% confidence interval [CI]: 1.03-4.37) and 2.22 (95% CI: 1.04-4.75), respectively. CONCLUSIONS: Our results reinforce the relationship between preoperative nutritional status and outcomes in elective spine surgery. The data indicate that preoperative prealbumin levels may be useful in risk stratification. Further study is needed to determine whether nutritional supplementation may reduce the risk of infection.