UNLABELLED: Minimally invasive procedures reduce the trauma of spine surgery. However, they are associated with high complexity of manipulations, long learning curve, need for expensive equipment for intraoperative navigation and significant irradiation. Various options for surgical approaches are being developed to reduce irradiation of medical staff and patients, surgery time and the number of drugs administered for general anesthesia. Simultaneous surgical interventions (SiSI) is one of these options. OBJECTIVE: To compare the effectiveness of simultaneous and staged minimally invasive dorsal decompression-stabilization procedures in patients with lumbar spine degenerative diseases. MATERIAL AND METHODS: A prospective study included 67 patients (41 men and 26 women) aged 48 (34; 56) years who underwent a single-level minimally invasive spinal root decompression and transforaminal interbody fusion via Wiltse posterior-lateral approach. Two study groups were distinguished: group I (simultaneous surgical interventions, SiSI) (=29), in which guide spokes and transpedicular screws were installed simultaneously by two surgeons within one x-ray session from two sides; group II (staged surgical interventions, StSI) (=38), in which staged transpedicular stabilization was performed (decompression side followed by contralateral side). Mean follow-up was 14 months in group I and 20 months in group II. We considered intraoperative fluoroscopy and irradiation dose, duration of surgery and anesthesia with calculation of doses of opioid drugs, blood loss, time of activation, hospital-stay and perioperative morbidity. Clinical outcomes were studied in long-term postoperative period. RESULTS: Simultaneous approach ensured less time of intraoperative fluoroscopy (=0.029) and irradiation dose (=0.035), duration of surgery (=0.01) and anesthesia (=0.02), amount of opioid drugs during anesthesia (=0.017). Blood loss, duration of activation and hospitals-stay were similar in both groups (=0.35, =0.12 and =0.57, respectively). There was comparable improvement in VAS score of pain in the lumbar spine and lower extremities in both groups (=0.63 and =0.31, respectively). According to SF-36 questionnaire, there was no between-group difference in physical and psychological components (=0.44 and =0.72, respectively). There was significantly greater number of adverse effects of anesthesia in the StSI group (26.2% vs. 6.8%, =0.003). At the same time, the number of surgical postoperative complications was similar in both groups (3.4% vs. 5.3%, =0.62). CONCLUSION: Simultaneous minimally invasive dorsal decompression-stabilization procedures have some significant advantages over staged approach regarding intraoperative parameters and adverse effects of anesthesia in patients with lumbar spine degenerative diseases. Nevertheless, there were similar clinical data and small incidence of surgical perioperative complications.