Introduction: the use of MIS treatment technologies results in fewer adverse outcomes and improved outcomes. However, the literature data on the factors that increase the number of complications, the frequency of reoperations and unscheduled re-hospitalizations in older patients operated on using MIS technologies are contradictory. In our work on a large cohort of patients, we studied the complications of minimally invasive surgical treatment of degenerative disease of the lumbar spine in older patients. The objective of the present paper was to study predictors of complications and unfavorable outcomes after minimally invasive surgical (MIS) treatment of degenerative lumbar spine pathology in elderly patients.
Methods: cohort of 1013 patients were operated using MIS technologies (decompression alone, TLIF, LLIF, ALIF) in 2013-2017. The mean age 66 years. The following data were collected: BMI, CCI, the presence of postoperative complications according to the classification of Dindo-Clavien and unplanned readmission at 90 days, hospital length of stay (LOS), surgical complexity (low, intermediate, and high), surgical time, and risk factors were evaluated. The cumulative reoperation rate was determined for 5 years of follow-up.
Results:
Most patients had excess body mass (30), with 327 (32%) patients having BMI above the normal threshold of 25 but below 30(25≤BMI<30).Class1obesity(30≤BMI<35)was observed in 322 (32%) patients, class 2 obesity (35 ≤ BMI < 40)—in 181 (18%) patients, and class 3 obesity (BMI > 40)—in 79 (8%) patients. Total 256 patients suffered a complication (25,2%), of them 226 were classified as mild (grade I, II, IIIA), 30 as severe (IIIB, IVA). Surgical complexity, BMI> 30, surgical time, number of operated levels were significantly associated with the risk of developing a complication. The overage number of hospital LOS in patient without and with complications were 6,3 and 9,3, respectively (p< 0,0001), and the unplanned readmission rate was 1,3%. The distribution of complications (n = 256) with respect to operation complexity was as follows: 99 (38.7%) after low-complexity operations (decompression alone), 136 (53.1%) after intermediate-complexity operations (MIS TLIF), and 21 (8.2%) after high-complexity operations (ALIF and LLIF). A higher risk of complications was found in patients who underwent intermediate-complexity surgery (MIS TLIF) compared with low (decompression alone) and more complex (MIS LLIF, MIS ALIF) surgical procedures (p <0.001 and p = 0.001, respectively). 104 patients underwent 133 revision operations. The 5-year cumulative reoperation rate was 15.2%, and the index of reoperations was 12.1%. Comparison of complication rates in the patients with various BMI values showed higher rates for patients with obesity (p = 0.007). CCI has no statistically significant effect on the incidence of complications when using the MIS options.
Discussion:
The registry of postoperative complications is an important tool for the health quality assessment and the choice of the surgical option, that help to establish measures to reduce them. The use of MIS technologies for treatment in elderly patients reduces the number of severe complications.