Validity of a new scoring system for assessment and decision guidance of misplaced pedicular screws.

Abstract

Background: Pedicle screw fixation in the thoracolumbar spine has become more widely accepted with advancements in instrumentation and clinical efficacy have been made. The optimal way to interpret pedicle screw cortical breaches had the subject of a great deal of research. None of the previous classifications and grading systems include full neurological deficits that may result from screw misplacement and do not provide clear guidance for the management of screw violations, which is crucially needed in the literature.

Objectives: Our study aimed to evaluate the reliability and validity of the use of a new scoring system (the Meshtawy Pedicular Screw Malposition - MPSM) for evaluating pedicle screw misplacement by a detailed clinical-radiographic comprehensive scoring system (MPSM) with sharp guidance for treating injurious violations by assessing the correlation between the neurological data of patients and computed tomography (CT) findings.

Patients and methods: This prospective case series included 100 patients (508 pedicular screws) who underwent transpedicular fixation at Orthopedic department Al-Azhar University Hospital, Assiut branch, Egypt 255 (50.2%) screws were inserted on the right side, while 253 (49.8%) were inserted on the left side. Intra-observer reliability was examined by calculating Cronbach's alpha intraclass correlation coefficient, which compares three measurements obtained by each observer at different time points. Inter-observer reliability was also examined by calculating Cronbach's alpha intraclass correlation coefficient and comparing the average measurements obtained by each observer.

Results: The MPSM demonstrated excellent (100%) intra-observer reliability for each observer regarding the violation score and total MPSM score. A strong positive and statistically significant correlation (Pearson test, P < 0.05) was found between severe neurological deficits and a greater degree of screw-pedicle violation.

Conclusion: MPSM scoring is a valid and reliable system for evaluating pedicular screw violations and their possible neurological consequences in the thoracic and lumbosacral spine from D7 to S1. Moreover, grades obtained from the MPSM score are helpful for making clear decisions for management.