The current study confirmed that perioperative hypoalbunemia was an important risk factors for wound complications following single-segment PLIF surgery[22-27]. Our study further confirmed that perioperative hypoalbuminemia are important risk factors for SWD and SSI.
Previous studies have reported that various markers of preoperative malnutrition are associated with surgical site infection following various types of surgery. Cross MB et al pointed out that superficial and deep SSI after orthopedic spinal surgery were associated with several markers of malnutrition, such as serological laboratory values, diabetes mellitus, hyperglycemia and obesity. Bohl DD et al investigated the relationship between preoperative hypoalbuminemia and complications within 30 days after total joint replacement. Compared with patients with normal albumin concentrations, patients with hypoalbuminemia had a higher risk of surgical site infection, pneumonia, prolonged hospital stay, and readmission. Similarly, they retrospectively reviewed data prospectively collected by the American College of Surgeons National Surgical Quality Improvement Program to investigate the relationship between preoperative hypoalbuminemia and complications after 30 days of posterior lumbar fusion. They pointed out that malnutrition was an independent risk factor for infection and wound complications after posterior lumbar fusion, and it was also associated with increased length of stay and readmission.
Our data showed that preoperative low serum albumin (<3.5 g/dL) was significantly associated with an increased risk of postoperative SWD (P=0.024) and SSI (P=0.040), which is consistent with other related reports. We combined the results of these data with previous literature and concluded that, preoperative serum albumin concentration can not only be used to measure nutritional status, but also is more closely related to poor wound healing and pathological inflammation. It is a reliable indicator for evaluating postoperative complications
In addition, early postoperative hypoalbuminemia has also been reported as a risk factor for serious postoperative complications[32-35]. Lee JI et al investigated 337 patients with major oropharyngeal squamous cell carcinoma who underwent clean and contaminated surgery and monitored serum albumin, glucose, and hemoglobin levels during the perioperative period. The results showed that early postoperative hypoalbuminemia <2.5 g/dl was an independent risk factor for SSI in patients who underwent oral cancer surgery. Bohl DD et al. also reported that malnutrition increased the risk of periprosthetic joint infection following total joint arthroplasty .
Low postoperative serum albumin (<3.0 g/dL) was significantly associated with an increased risk of postoperative SWD. However, low postoperative albumin is affected by many factors. Ge X et al noted that the stress response, perioperative fluid overload, hemodilution, albumin redistribution, a breakdown of metabolism and other comprehensive factors cause postoperative albumin decline. Despite this, we still need to be wary of hypoalbuminemia with albumin levels <3.0 g/dl after surgery. Considering low hypoalbuminemia mechanisms, monitoring the albumin serum level and giving albumin supplementation in case of low level appeared to be an adequate strategy to decrease the risk.
Chronic steroid users (steroid usage for more than 10 days preoperatively) have reportedly increased their risk of infection by two- to three-fold after surgery. Singla A et al reported chronic steroid usage to be a significant risk factor for SSI in their database analysis of 360,005 patients over 65 years of age.
Univariate logistic regression showed that poor drainage after surgery could lead to SWD. This may be related to the poor placement of the drainage tube and blockage of the drainage tube. Irregular drainage after surgery is prone to deep congestion and hematoma, and then SWD and also increased risk of SSI. Although p value of postoperative drainage (P=0.003) was less than 0.05, OR value was close to 1 infinitely, which may be related to the small sample size of SSI group. Expanding the sample size is helpful for further research. Increased risk of SSI in patients with spondylolisthesis could be explained by prolonged bed rest after PLIF surgery, considering that short-term(7 days) could be beneficial to the stability of the spine after reduction to prevent loosening or displacement of the internal fixation. The elderly patients also needed to be alert to SSI after the operation (P=0.010). However, this should be further evaluated in future prospective experiments with increased sample sizes.
When malnutrition is detected, timely nutritional supplementation is beneficial to patients' postoperative recovery. Oral nutritional supplements have been shown to be effective in improving nutrient intake, and they can also be given intravenously. Avenell A et al proved that oral non-protein energy, protein, vitamin and mineral supplements can prevent complications after hip fracture in the elderly.
The strengths of this study include the use of the same surgical procedure (PLIF) for lumbar fusion and internal fixation. Only single-segment fusion patients were included to reduce the impact of surgical procedures on the results of the study. In future research, it will be important to further explore, elucidate, and establish potential links between malnutrition and adverse surgical wound outcomes after spinal fusion surgery.
The study was limited by the inherent problems of retrospective studies. First, as a retrospective, single institution study, all data on patient characteristics, laboratory test results, medical interventions directly related to abnormal laboratory values, and patient clinical symptoms were dependent on the inherent limitations of the files in the electronic medical record system. Second, the sample size of patients with preoperative hypoalbuminemia (13 cases) was relatively small, and a larger sample size may have been helpful for the statistical analysis. Although the serum albumin value is a valuable tool for assessing nutritional status, it is affected by many perioperative factors, so it cannot be a comprehensive assessment of the nutritional status of patients. We still need to integrate the general situation of patients and other serological indicators to guide clinical treatment.