A study into the clinical features that most strongly correlate to radiographic findings of mid-face fractures Beech A. N. Knepil G. J. Department of Oral and Maxillofacial Surgery, Gloucestershire Royal Hospital, Great Western Road, Gloucester, UK 1. BACKGROUND Initial assessment of patients with facial injuries is of vital importance to identify patients who may have a displaced bony injury or ophthalmic injuries requiring urgent intervention. The decision to order radiographs is based on clinical features, but there are currently no formal guidelines as to which signs or symptoms require further investigation. Previous evidence suggests that the use of a scenario-specific pro-forma can aid management and improve the quality of care of patients in an Emergency Department in the UK.1,2 The aim of our project was to assess which clinical signs or symptoms are of greatest value in identifying patients with facial bony injuries in the hope of reducing the number of unnecessary radiographs to patients in the future. 3. RESULTS Bivariate analysis was performed to identify possible associations between clinical and radiographic findings. Alpha value was set at 0.005 with a Bonferroni correction for multiple testing. Clinical findings were treated as separate diagnostic tests for assessment of sensitivity, specificity and likelihood ratios, together with a test-specific power analysis. Table 2: Correlations between clinical features and radiographic features (significant findings highlighted Table 3: Evaluation of significant clinical findings as a diagnostic test – sensitivity, specificity and predictive values Pearson Correlation with Radiographic Findings Index Clinical feature Pearson Correlation N Sig (2-tailed) Neurological head injury* 0.218 350 4.00E-05 C-spine injury 0.4 332 0.471 Pupils equal and react to light -0.78 308 0.172 Anaesthesia, paraesthesia to lip/cheek or side of nose* 0.291 264 1.56E-06 Severe soft tissue swelling -0.45 255 0.476 Visual acuity -0.73 228 0.274 Diplopia 0.094 217 0.168 Double vision 0.064 199 0.371 Multiple or severe trauma 0.043 166 0.581 Palpable bony step* 0.618 155 1.03E-17 Bony asymmetry* 0.55 141 1.61E-12 Lateral sub conjunctival haemorrhage with no posterior limit* 0.474 100 6.45E-07 Malocclusion 0.077 92 0.468 Enopthalmous -0.072 89 0.5 Pain on biting 0.235 82 0.033 Restricted movement of mandible 80 0.009 Palpable emphysema -0.22 62 0.086 2. METHOD A pilot, retrospective case note audit was performed to assess current practice in this area. It identified that medical record keeping was often incomplete, and that negative clinical findings were rarely recorded. A minimum data set of 17 key clinical pieces of information was agreed by internal consensus of senior Oral and Maxillofacial surgeons within our department. This was informed by a literature search, and was aimed at excluding ophthalmic injuries, as well as identifying patients who may have displaced bony injuries. Data was then gathered as part of a prospective single centre, registered audit in a large district general hospital in the United Kingdom. The sampling period ran from December 2013 to February 2015. Clinicians who participated in the audit included Oral and Maxillofacial and Emergency Department doctors of all levels of seniority. To aid data collection a minimum data set tool (Figures 1) was introduced to be used on all facial injury patients in which a fracture was suspected and radiographs taken: Figure 1: Facial Injury Pathway data collection tool Radiographic findings were coded in one of 3 categories (Table 1) to allow for statistical analysis of the results: Clinical Feature Neurological head injury Anaesthesia, paraesthesia to lip/cheek or side of nose Palpable bony step Bony asymmetry Lateral sub conjunctival haemorrhage with no posterior limit Sensitivity 25.53% 27.08% 50.00% 43.24% 41.67% 95% CI 12.80-37.50% 15.29-41.85 % 33.81-66.19 % 27.11-60.51% 25.53-59.24 % Specificity 95.65% 93.52% 97.39% 94.23% 87.50% 12.68-97.66 % 89.36-96.41 % 92.56-99.43 % 87.86-97.84% 76.84-94.43 % Positive likelihood ratio 5.41 4.18 19.17 7.5 3.33 2.62 to 11.19 2.10 to 8.31 6.01 to 61.08 3.17 to 17.71 1.57 to 7.09 Negative likelihood ratio 0.8 0.78 0.51 0.6 0.67 0.69 to 0.93 0.65 to 0.93 0.38 to 0.70 0.45 to 0.80 0.50 to 0.89 Positive Predictive Value 48.00% 48.15 % (*) 86.96 72.73% 65.22 % (*) 27.82-68.68 % 28.68-68.04 % 66.38-97.07% 49.78-89.20% 42.74-83.58 % Negative Predictive Value 88.00% 85.23 % (*) 84.85 82.35% 72.73 % (*) 83.96-91.33 % 80.06-89.49% 77.57-90.49% 74.30-88.73% 61.38-82.25% Radiographic index Radiographic findings No bony injury demonstrated on radiographs 1 Radiographic anomaly not in keeping with a displaced fracture 2 Radiographic findings in keeping with a displaced fracture 5. CONCLUSION 5 clinical features were isolated as strongly correlating to the radiographic finding of mid-face fractures in patients examined. Other features, particularly swelling, had a weaker correlation. We are using this data to inform the development of robust screening tool to reduce the number of unnecessary radiographs taken in facial injury patients. 4. DISCUSSION From the group of patients included in the data-set, we identified the following as strongly indicative of a mid-face fracture: altered facial sensation in the distribution of the infraorbital nerve palpable bony steps facial bony asymmetry lateral sub conjunctival haemorrhage with no posterior limit There was no evidence of an association between “multiple or severe trauma” and facial bony injuries, or between cervical spine injury and facial bony injuries. Presence of a neurological head injury did however show an association. Our data tool not only improved record keeping, but also gave us important information in the prediction of a likely fracture and indication for further investigation i.e. radiology 6. REFERENCES Bachmann LM, Kolb E, Koller MT, Steurer J, ter Riet G. Accuracy of Ottawa ankle rules to exclude fractures of the ankle and mid-foot: systematic review. BMJ. 2003 Feb 22;326(7386):417 Emparanza JI, Aginaga JR. Validation of the Ottawa Knee Rules Ann Emerg Med. 2001 Oct;38(4):364-8.