S Haleem1, M Malik2, C Azzopardi3, R Botchu3, D S Marks3. 1. Spinal House, Royal Orthopaedic Hospital, The Woodlands, Bristol Road South, Birmingham, B31 2AP, UK. shahnawaz.haleem@gmail.com. 2. Division of Medical Education, University of Brighton, Brighton, UK. 3. Spinal House, Royal Orthopaedic Hospital, The Woodlands, Bristol Road South, Birmingham, B31 2AP, UK.
Abstract
PURPOSE: Intracanal rib head penetration is a well-known entity in dystrophic scoliotic curves in neurofibromatosis type 1. There is potential for spinal cord injury if this is not recognised and managed appropriately. No current CT-based classification system is currently in use to quantify rib head penetration. This article aims to propose and evaluate a novel CT-based classification for rib head penetration primarily for neurofibromatosis but which can also be utilised in other conditions of rib head penetration. MATERIALS AND METHODS: The grading was developed as four grades: normal rib head (RH) position-Grade 0, subluxed extracanal RH position-Grade 1, RH at pedicle-Grade 2, intracanal RH-Grade 3. Grade 3 was further classified depending on the head position in the canal divided into thirds. Rib head penetration into proximal third (from ipsilateral side)-Grade 3A, into the middle third-Grade 3B and into the distal third-Grade 3C. Seventy-five axial CT images of Neurofibromatosis Type 1 patients in the paediatric age group were reviewed by a radiologist and a spinal surgeon independently to assess interobserver and intraobserver agreement of the novel CT classification. Agreement analysis was performed using the weighted Kappa statistic. RESULTS: There was substantial interobserver correlation with mean Kappa score (k = 0.8, 95% CI 0.7-0.9) and near perfect intraobserver Kappa of 1.0 (95% CI 0.9-1.0) and 0.9 (95% CI 0.9-1.0) for the two readers. CONCLUSION: The novel CT-based classification quantifies rib head penetration which aids in management planning.
PURPOSE: Intracanal rib head penetration is a well-known entity in dystrophic scoliotic curves in neurofibromatosis type 1. There is potential for spinal cord injury if this is not recognised and managed appropriately. No current CT-based classification system is currently in use to quantify rib head penetration. This article aims to propose and evaluate a novel CT-based classification for rib head penetration primarily for neurofibromatosis but which can also be utilised in other conditions of rib head penetration. MATERIALS AND METHODS: The grading was developed as four grades: normal rib head (RH) position-Grade 0, subluxed extracanal RH position-Grade 1, RH at pedicle-Grade 2, intracanal RH-Grade 3. Grade 3 was further classified depending on the head position in the canal divided into thirds. Rib head penetration into proximal third (from ipsilateral side)-Grade 3A, into the middle third-Grade 3B and into the distal third-Grade 3C. Seventy-five axial CT images of Neurofibromatosis Type 1patients in the paediatric age group were reviewed by a radiologist and a spinal surgeon independently to assess interobserver and intraobserver agreement of the novel CT classification. Agreement analysis was performed using the weighted Kappa statistic. RESULTS: There was substantial interobserver correlation with mean Kappa score (k = 0.8, 95% CI 0.7-0.9) and near perfect intraobserver Kappa of 1.0 (95% CI 0.9-1.0) and 0.9 (95% CI 0.9-1.0) for the two readers. CONCLUSION: The novel CT-based classification quantifies rib head penetration which aids in management planning.
Authors: Michael H Abdulian; Raymond W Liu; Jochen P Son-Hing; George H Thompson; Douglas G Armstrong Journal: J Pediatr Orthop Date: 2011 Jan-Feb Impact factor: 2.324