Pedicle screw placement is challenging in deformity correction surgeries in complex paediatric kyphoscoliosis. Though navigation and robotics can improve the accuracy of screw placement, they are costly and not widely available. We aim to assess the feasibility, efficacy and cost-effectiveness of Dry-Run-Surgical-Simulation (DRSS) utilizing specifically designed 3-D printed (3DP) patient-specific spine models to improve the accuracy of screw placement in complex spinal deformity correction surgeries. 3DPPS models were manufactured by altering the cancellous core to match the patient’s cancellous bone density to enable the surgeon to get a haptic feedback during pedicle screw simulation. In a single-center prospective clinical study, 3DP patient-specific spine models were utilized for virtual planning, pre-operative DRSS of pedicle screw placement and as intraoperative guide for pedicle screw placement in 26 patients (14 males,12 females) with complex kyphoscoliosis who underwent instrumented deformity correction surgeries. Results were compared to a similar historic cohort of 29 patients (control group) who underwent deformity correction without using 3DP models. The mean operative time was significantly less in the 3D-printed-dry run simulation (3DPS) group (344.1+/-53.8min, range 240 – 430 min) vs control group (398.2+/-65.3min, range 310 – 540min), p<0.05.The intraoperative blood loss was significantly less in the 3DPS group (390.8+/- 144.2 ml, range 400 – 650 ml) vs control group (460.5+/-83.2 ml, range 550 – 900 ml), p<0.05. Pedicle screw placement accuracy was significantly higher in 3DPS group [92.3% (227/246 screws)] in comparison with the control group [82.7% (215/260 screws)]. Critical pedicle breaches causing neurological deficits were significantly higher in the control group (n=2) vs 3DP group (n=0).The mean scoliosis and kyphosis correction rates were comparable in both groups. The mean VAS, ODI and SRS-22r scores were comparable in both groups. The mean cost of a DRSS-3DPPS model per surgery was significantly lower[125 USD (3DPPS model) vs 1225 USD (for navigation)]. DRSS of pedicle screw placement on 3DP patient-specific spine models are a feasible, safe and cost-effective alternative to navigation and robotics in complex spine deformity correction surgeries.