Comparison of fusion-assisted direct and indirect decompression in patients with segmental instability and lumbar spinal canal stenosis

Objective: In our study, we aim to compare the radiological and clinical outcomes of patients who underwent direct and indirect decompression surgery following posterior lumbar stabilization and fusion. By dividing patients into two groups, we intend to determine the less invasive surgical option with a lower complication risk. Material and Methods: Between January 1, 2022, and March 31, 2024, 1332 patients who underwent brain and neurosurgery operations at our hospital were screened. 54 patients with preoperative diagnoses of spondylolisthesis and lumbar spinal stenosis, who had both preoperative and postoperative images in the hospital PACS system and at least 6 months of follow-up, were included in the study. Clinical data including preoperative age, sex, VAS pain scores, neurogenic claudication distance, neurological muscle strength examination, duration of complaints, pain characteristics, concomitant diseases, operative plans, and postoperative hospital stay duration, presence of complications, admission and discharge hemoglobin levels, operation duration, 1-month and 6-month outpatient follow-up controls include VAS pain scores, neurogenic claudication distance, muscle strength examinations, and pain characteristics were obtained from the hospital system. Radiological data included: presence of instability on preoperative dynamic (flexion-extension) radiographs, central canal area, lateral recess width, central canal diameter, intervertebral foramen area, intervertebral foraminal narrowing degree on preoperative magnetic resonance imaging axial sections, pars interarticularis defect, disc space height, spondylolisthesis degree and amount, intervertebral foraminal area on preoperative computed tomography imaging sagittal sections, disc space height, spondylolisthesis amount, intervertebral foraminal area measurements on postoperative computed tomography imaging sagittal sections within the first 24 hours, measured by an experienced radiologist with 4.5 years of experience, blinded to the clinical data. Patients who underwent posterior lumbar stabilization surgery were divided into two groups: 23 patients who underwent direct decompression surgey (total laminectomy, partial laminectomy, foraminotomy, discectomy, facetectomy) and 31 patients who underwent indirect decompression surgery (distractive decompression) after fusion. The radiological, clinical, and laboratory data of these two groups were statistically compared. Results : Statistically significant relationship was found between the groups of patients and the occurrence of complications (p = 0.026 < 0.05). Complication rates were higher in the fusion + direct decompression group. In terms of clinical treatment effectiveness, the average postoperative 6- month VAS score was 1.16 ± 2.24 in the fusion + indirect decompression group and 1.48 ± 2.54 in the fusion + direct decompression group. There was no significant difference in postoperative 6-month VAS scores (p>0.05). In terms of postoperative 6-month neurogenic claudication (meters), the average was 300.00 ± 230.94 in the fusion + indirect decompression group and 113.00 ± 135.90 in the fusion + direct decompression group. There was no significant difference in postoperative 6-month neurogenic claudication (p>0.05). Pre-discharge hemoglobin level was found to be 10.67 ± 1.04 in the fusion + indirect decompression group and 10.02 ± 0.87 in the fusion + direct decompression group (p = 0.018 < 0.05). This indicates that the pre-discharge hemoglobin level was significantly higher in the fusion + indirect decompression group.When comparing hospital stay durations, the average stay was 6.87 ± 3.27 days in the fusion + indirect decompression group, and 8.30 ± 4.45 days in the fusion + direct decompression group (p = 0.045 < 0.05). This shows that the hospital stay was significantly longer for the fusion + direct decompression group. Conclusion: The results of our study showed no statistically significant difference in clinical follow-up between the patient groups who underwent direct and indirect decompression. The treatment effectiveness was similar, but the complication rate was higher in the direct decompression group. These findings support the consideration of indirect decompression as a surgical option, as it is less invasive and has a lower complication rate while achieving similar treatment effectiveness. Keywords: Spondylolisthesis, Spinal Stenosis, Indirect Decompression, Direct Decompression, Stabilization