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Purpose. To quantify the risk of clinically overt venous thromboembolism (VTE) and major bleeding (MB) during the first year following surgery for lumbar spinal stenosis (LSS) relative to a matched population cohort.

Methods: This nationwide, retrospective cohort study utilized data from the Swedish National Spine Register (Swespine), including 77,145 patients who underwent surgical treatment for LSS between 2003 and 2023. These patients were matched 1:5 to 385,388 referents from the general population. Outcomes (VTE and MB) were identified through cross-linkage with the National Patient Register (NPR) and the Swedish Stroke Register (Riksstroke). Adjusted Cox piecewise regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for VTE and MB across prespecified postoperative intervals.

Results: Within the first 30 days after inclusion, patients exhibited substantially higher incidence rates of venous thromboembolism (VTE) and major bleeding (MB) compared with referents. The incidence rate of VTE was 30.39 per 1,000 person-years among patients versus 8.14 among referents, while the corresponding rates for MB were 88.78 and 31.87 per 1,000 person-years, respectively. Compared with referents, patients had a HR of 3.68 (95% CI, 3.05-4.44) for VTE and a HR of 2.52 (95% CI 2.27-2.80) for MB within the first 30 days after inclusion. The risk for VTE remained elevated through the 31–60-day interval (HR 2.09; 95% CI, 1.63-2.69), whereas the risk for MB declined sharply after the first month (HR 1.02; 95% CI 0.87-1.21).

Conclusion: Patients undergoing surgery for LSS face a significantly higher risk for VTE and MB compared to a matched population. This hazard was most acute during the first 30 postoperative days. While these risks decline sharply thereafter, the risk of VTE remains significantly elevated during the first 2 months following LSS surgery.

PURPOSE: To describe the incidence of stroke in the first year after surgery for lumbar spinal stenosis (LSS).

METHODS: The study included 64,179 Swedish National Spine Register (Swespine) patients who underwent surgery for LSS between 2001 and 2020. The primary outcome was the diagnosis of stroke within the first year after surgery, as documented in the Swedish Stroke Register. The incidence was quantified as the number of strokes per 1,000 surgeries within a defined period, inclusive of the incidence rate (number of strokes/100,000 person-years). An adjusted Cox regression model was used to analyse whether age, sex, smoking, or surgery with implants further increased the risk of stroke.

RESULTS: In the first year after surgery, 426 patients (0.66%) developed a stroke. The risk of stroke was highest during the first 30 days (n=72, 0.11%). Stroke incidence was 1.1/1,000 surgeries during the first 30 days and 6.6/1,000 surgeries during the first year after surgery. The incidence rate during the initial 30 days was 1,394 strokes per 100,000 person-years, while the incidence rate during the first year was 660 strokes per 100,000 person-years. Smoking (hazard ratio [HR], 1.82; 95% confidence interval [CI], 1.31-2.52), age 65-74 years (HR, 2.65; 95% CI, 1.91-3.67), and age ≥75 years (HR, 6.04; 95% CI, 4.42-8.25) further increased the risk of stroke.

CONCLUSION: The incidence of stroke after LSS surgery was the highest during the first 30 days. However, the absolute number of strokes was small. The risk of stroke could be of minor concern for most of the patients even if older age and smoking were identified as risk factors.

PURPOSE: To validate the Swedish National Spine Registry (Swespine) for diagnostic accuracy and documentation of surgical procedures for central lumbar spinal stenosis (CLSS) and lumbar disc herniation (LDH), including an analysis of preoperative magnetic resonance imaging (MRI). Additionally, this study evaluates the accuracy and completeness of perioperative data and documented complications.

METHODS: Of 41,312 patients registered in Swespine for CLSS or LDH between January 2017 and December 2022, 800 were randomly selected from four hospitals. The electronic patient records were used as the gold standard. Radiological criteria for CLSS and LDH were established through a review of MRI scans.

RESULTS: The proportion of correctly classified diagnoses (PCC) was 98.5% for CLSS and 99.2% for LDH, while the PCC of the type of surgery was 99.7% and 98.5% in the CLSS and LDH cohorts, respectively. Preoperative MRI analysis showed that 94.2% of patients undergoing CLSS surgery at the narrowest spinal level were classified as Schizas C or D, with a mean cross-sectional area of 44.2 mm². In comparison, 85.0% of patients who underwent LDH surgery were classified with Pfirrman grade 3.

CONCLUSION: Swespine demonstrated high accuracy and completeness in diagnosing and surgically treating CLSS and LDH patients, as corroborated by preoperative MRI assessments. Most perioperative data, including complications, demonstrated acceptable to excellent registration. Improvements are recommended in the documentation of the American Society of Anaesthesiologists classification, patient weight and height, smoking status, use of implants and bone grafts, date of discharge, use of thromboprophylaxis, and previous surgeries.

Introduction: Surgery for lumbar spinal stenosis (LSS) is one of the most common indications for elective spine surgery in developed countries and postoperative cerebrovascular complications must be taken into consideration. The main objective of this study was to determine and investigate the risk of stroke during the first year after surgery for LSS.

Materials and Methods: This retrospective register study included 64,179 patients from the Swedish spine register (Swespine) operated from 2001 through 2020 for central or lateral LSS. Outcomes were collected from the Swedish stroke register (Riksstroke). The primary outcome was the diagnosis of peri- or postoperative ischemic/hemorrhagic stroke within the first year after LSS surgery. The registers included background data like sex, age, smoking, and previous spine surgery, in addition to surgical/stroke care data like levels of decompression, surgery with instrumentation, type of stroke and length of hospitalisation. Initial analysis with histograms and a life table was used to present the hazard of stroke during the first year after surgery. An adjusted cox regression model was used to analyse the risk for stroke. The model was adjusted for age (<64, 65-74, ≥75), sex, smoking and whether implants were used or not.

Results: During the first year after surgery 426 patients (0,66%) developed a stroke. Out of these 37 (0,06%) were classified as hemorrhagic, 379 (0,59%) as ischemic and 10 (0,02%) as unclassified. The risk for stroke was highest during the first 30 days (n=72, (0,11%)). Smoking (HR, 1,82; 95% CI, 1,31-2,52; p<0,001), age 65-74 years (HR, 2,65; 95% CI, 1,91-3,67; p<0,001) and age ≥75 years (HR, 6,04; 95% CI, 4,42-8,25; p<0,001) were associated as risk factors for postoperative stroke. Surgery with implants was not associated with an increased risk (HR, 1,01; 95% CI, 0,73-1,40; p=0,967).

Conclusion: The peri- and postoperative risk for stroke during the first year after LSS surgery was 0,66% and increased age and smoking were identified as risk factors. The highest number of strokes occurred during the first 30 days and more specific, the first days after surgery. This study gives the basis for further research of cerebrovascular complications after LSS surgery.