Pedicle screw fixation is an effective and reliable method for achieving stabilization in lumbar degenerative disease. The procedure carries a risk of violating the spinal and neural canal which can lead to nerve injury. This audit examines the accuracy of screw placement using intra-operative image guidance.

Retrospective audit of patients undergoing lumbar pedicle screw fixation using image guidance systems over an 18-month period. Case records were reviewed to identify complications related to screw placement and post-operative CT scans reviewed to study the accuracy of screw position.

Of the 98 pedicle screws placed in 25 patients, pedicle violation occurred in 4 screw placements (4.1%). Medial or inferior breach of the pedicle cortex was seen in 2 screws (2%). Nerve root injury as a consequence of this violation was seen in one patient resulting in irreversible partial nerve root dysfunction. Mean set up time for the guidance system was 42 minutes. The mean operative time was 192 minutes.

Violation of either the medial or inferior pedicle cortex during placement of fixation screws is a rare, but potentially serious complication bearing lasting consequences. Image-guided placement can be helpful and possibly improve accuracy; particularly in patients with distorted spinal anatomy.

Due to the presence of megakaryocytes, platelets and clotting factors, bone marrow aspirate (BMA) tends to coagulate. For the first time, starting from our previous studies on mesenchymal vertebral stem cells, it has been hypothesized that coagulated BMA represents a safe and effective autologous biological scaffold for bone regeneration in spinal surgery. The present research involved advanced preclinical in vitro models and the execution of a pilot clinical study. Evaluation of cell morphology, growth kinetics, immunophenotyping, clonogenicity, trilineage-differentiation, growth-factors and HOX and TALE gene expression were analyzed on clotted- and un-clotted human V-BMA. In parallel, a pilot clinical study on ten patients with degenerative spine diseases submitted to instrumented posterior arthrodesis, is ongoing to assess the ability of clotted-V-BMA to improve spinal fusion at 6- and 12-months follow-up. Results demonstrated that clotted-V-BMA have significantly higher growth-factor expression and mesenchymal stem cell (MSCs) viability, homogeneity, clonogenicity, and ability to differentiate towards the osteogenic phenotype than un-clotted-V-BMA. Clotted-V-BMA also highlighted significant reduced expression of PBX1 and of MEIS3 genes negatively involved in osteoblast maturation and differentiation. From December 2020, eight patients have already been enrolled with first promising results that will be finally evaluated in the next two months. The application of V-BMA-clot as carrier of progenitors and cytokines and as natural scaffold with a structural texture represents a point-of-care orthobiologic product to improve spinal fusion. Clinical application seems to be efficacy, and we will confirm and strengthen these data with the final results of the pilot clinical study