Dental Traumatology 2015; doi: 10.1111/edt.12165
Traumatic head injuries in patients with maxillofacial fractures: a retrospective case–control study Hai-Hua Zhou1,2, Qi Liu1,2, Rong-Tao Yang1,2, Zhi Li1,2, Zu-Bing Li1,2 1 The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University; 2Department of Oral and Maxillofacial Surgery, College and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
Key words: Head injury; Maxillofacial fractures; Prevalence; Retrospective study Correspondence to: Dr. Zu-Bing Li, Department of Oral and Maxillofacial Surgery, College and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, China Tel.: +86 27 87686215 Fax: +86 27 87873260 e-mail: [email protected] Accepted 9 December, 2014
Abstract – Objectives: To analyse and evaluate the correlation between traumatic head injuries (THIs) and maxillofacial fractures (MF). Age, gender and trauma mechanism correlated with THI were also investigated. Patients and Methods: We conducted a hospital-based retrospective case–control study at Stomatology College and Hospital, Wuhan University. From January 2000 to December 2009, a total of 1131 patients with MF were enrolled in the statistical study to evaluate the association of THI and other risk factors with MF. Among these patients, 86 presented with THI. We utilized binary logistic regression and risk analysis to investigate the associations among MF and other risk factors with HI. Results: Head injuries (103 injuries) were sustained by 86 patients (7.6%), with male-to-female ratio of 4.1:1.0. Most of the patients (52 patients, 50.5%) also exhibited cranial bone fractures. The age group with most patients was the 30–39 years age group (26 patients, 30.2%), followed by the 19– 29 years age group (22 patients, 25.6%). Motor vehicle accident (MVA) was the most common mechanism of injury (49 patients, 74.1%). Patients older than 50 years showed the highest risk for head injury (OR, 2.0; 95% confidence interval, 1.1–3.7; P = 0.025). MVA had a sixfold risk of head injury (OR, 6.2; 95% confidence interval, 1.5–26.1; P = 0.013). Head injuries were more prone to occur in patients who had combined fracture of the mid-face and mandible (OR = 4.6, P < 0.001), and only a 0.3-fold risk of multimandible fractures (P < 0.001), 0.5-fold risk of single mandibular fracture (P = 0.017) and 0.3-fold risk of patients who sustained only single mandibular condylar fracture (P = 0.019). Conclusions: The occurrence of head injuries is significantly related to age, aetiology and the pattern and position of maxillofacial fractures.
Patients with maxillofacial fractures (MF) may also suffer from traumatic head injuries (THIs) because of the close anatomic proximity of the facial bone and cranium (1–5). Previous studies have revealed that MF are usually associated with THI, and various incidences of THI (5.4–45.5%) have been reported (1, 5–10). A study based on the National Trauma Data Bank (NTDB) in the US showed a high incidence of patients with MF who also suffered from THI (67.9%) (11). The more serious the MF are, the higher (86%) the probability of occurrence of THI (12). However, researchers have different opinions with regard to the relationship between MF and THI. Some researchers speculate that the facial bone absorbs the energy of the impact, protecting the brain from injury (13, 14). Other researchers believe that high-velocity impacts with sufficient force to break facial skeletons may also cause serious head injuries, such as intracranial haemorrhages (15–17). Haug et al. refuted theories stating that facial © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
bones act as cushions to protect the cranium and its contents (4). Keenan et al. found that the risk of serious intracranial injury in patients with facial trauma increased by almost tenfold (18). To reduce mortality and morbidity and to improve the outcome of treatments in patients with MF, early detection of associated THI remains an important procedure among patients with MF (5, 18, 19). A number of retrospective studies have been conducted to investigate the correlation between THI and MF. Despite some controversial reports, it has been suggested that THI is associated with MF. Nevertheless, multiple factors and potentially significant confounding variables result in difficulty in obtaining the accurate assessment of the relationship between THI and MF. The previous studies on this subject vary in the selection of populations, sample sizes, methodology and analysis results. Therefore, it is necessary to further delineate the involvement of THI, together with other related risk 1
2
Zhou et al.
factors, in MF with large sample size and strict analysis methodology. In this study, we conducted a hospital-based case– control study to analyse and evaluate the correlation between THI and MF. The occurrence of THI in relation to age, gender, trauma mechanism and type of MF was also investigated. We hypothesized that the THI is related to the pattern and position of the MF. We also hypothesized that the occurrence of THI is influenced directly by the energy directed by external force, the high external force in high-velocity accidents (motor vehicle accidents) leading to the higher probability of THI in patients with MF. We additionally hypothesized that older adults would be more susceptible to THI relative to young controls. Materials and methods Ethics statement
We conducted a hospital-based retrospective case–control study at Stomatology College and Hospital, Wuhan University, from January 2000 to December 2009. The protocol, survey forms and consent forms were approved by the Institutional Review Board (IRB) of Wuhan University. Written consent given by the patients was waived by the approving IRB. Study population and data collection
Patients with MF admitted in the Department of Oral and Maxillofacial Surgery, Stomatology College and Hospital, Wuhan University from January 2000 to December 2009 were enrolled in this study. Patients were excluded as study subjects based on the following: (i) repeated admissions and (ii) incomplete information. In total, 1131 participants had complete diagnostic records with MF. Information and data, which included age, gender, mechanism of injury, type of MF and type of THI, were collected and standardized by an investigator based on the patients’ case histories, clinical and radiographic examinations and medical records. Initial cranial CT was performed in all patients with neurological abnormalities, impaired consciousness or clinical signs of skull fracture, which were further diagnosed by a radiologist. Therefore, the neurological data in this study were based on the information obtained from historic diagnoses (who had ever admitted and diagnosed in the department of neurosurgery of other hospitals), clinical and CT examinations. The mechanisms of injury were classified as assault, road traffic accident [motor vehicle accident (MVA), motorcycle accident and bicycle accident], fall (at ground or high levels), sports- or work-related accident and others. MFs were categorized as exclusively mid-facial fractures (multiple or single), combined fractures of the mid-face and mandible, multiple mandibular fractures and single mandibular fracture (symphysis, condyle, body, angle, ramus, coronoid or alveolar fracture). The type of THIs was grouped according to cranial bone fractures (basal skull, frontal, temporal, occipital sphenoid and other skull fracture), intracranial problems
(cerebral contusion, pneumocephalus, epidural haematoma, subdural haematoma, subarachnoid haemorrhage, intracerebral haematoma, intracranial haemorrhage and cerebrospinal fluid leakage), concussion (patients with loss of consciousness without signs of intracranial haemorrhage were diagnosed with concussion) (18) and other injuries (traumatic brain injury, open brain injury, scalp laceration and scalp haematoma). The patients were grouped into 0–9, 10–19, 20–29, 30– 39, 40–49 and 50 years and above (only three patients in test group were older than 60 years; therefore, we combine the patients in the group 50 years and older. Case group and control group
Among the patients with MF, 86 patients diagnosed with THI were used as the case group. Other patients (1045 patients) with MF but without THI were used as the control group. Statistical analysis
Statistical analysis was performed using SPSS software (version 16.0; SPSS, Chicago, IL, USA). Continuous variables were reported as mean SD and were assessed by independent samples t tests as necessary. The two-tailed nonparametric Mann–Whitney U-test was used when variances were not equal among series. The chi-square test was used to compare categorical variables. Fisher exact test was utilized when observation in any cell of the 2 9 2 table was expected to be less than five. Odds ratio and 95% confidence interval were used to assess the risk of sustaining head injuries. Logistic regression analysis was used to control confounding variables. Probabilities of P < 0.05 were considered to be significantly different. Results Incidence of THI following MF
In the 10-year period of this study, 1131 patients with MF were registered and analysed, with male-to-female ratio of 3.5:1.0 (881 men and 250 women). Among these 1131 patients, 7.6% (86 patients) presented with associated THI, with male-to-female ratio of 4.1:1.0 (69 men and 17 women). The age range of the patients associated with THI was 4–70 years (average 34.5 13.6 years). The age group with the most patients was the 30– 39 years age group (26 patients, 30.2%), followed by the 20–29 years age group (16 patients, 18.6%). In this sample, MVA was the most common mechanism of injury (49 patients, 74.1%), followed by motorcycle accidents (12 patients, 14.0%), falls (12 patients, 14.0%) and assault (seven patients, 8.1%) (Table 1). We observed that 50.5% of the patients (52 patients) with THI sustained cranial bone fractures. The most common site of cranial bone fractures was the base of the skull (20 patients, 19.4%), followed by the frontal bone (17 patients, 16.5%) and temporal bone (six patients, 5.8%) (Table 2). Thirty-six patients (35.0%) sustained intracranial problems. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Traumatic head injuries in maxillofacial fractures
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Table 1. Logistic regression analysis: risk of head injuries in patients by age, gender and aetiology THI
Sex Male Female Age Aetiology Assault Bicycle MVA Fall ground Fall high Motorcycle Sport Work
Present n (%)
Absent n (%)
Significance (Crude)
69 (80.2) 17 (9.8) 34.5 13.6
812 (77.7) 233 (22.3) 30.8 13.4
7 (8.1) 3 (3.5) 49 (57.0) 2 (2.3) 10 (11.6) 12 (14.0) 0 1 (1.2)
152 64 300 134 111 167 20 26
(14.5) (6.1) (28.7) (12.8) (10.6) (16.0) (1.9) (2.5)
Odds ratio (adjusted)
95% CI
Significance (adjusted)
0.587
1.1
0.6–1.9
0.751
0.013
1.0
1.0
0.009
0.100 0.320
Traumatic head injuries in patients with maxillofacial fractures: a retrospective case–control study Hai-Hua Zhou1,2, Qi Liu1,2, Rong-Tao Yang1,2, Zhi Li1,2, Zu-Bing Li1,2 1 The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University; 2Department of Oral and Maxillofacial Surgery, College and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, China
Key words: Head injury; Maxillofacial fractures; Prevalence; Retrospective study Correspondence to: Dr. Zu-Bing Li, Department of Oral and Maxillofacial Surgery, College and Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, China Tel.: +86 27 87686215 Fax: +86 27 87873260 e-mail: [email protected] Accepted 9 December, 2014
Abstract – Objectives: To analyse and evaluate the correlation between traumatic head injuries (THIs) and maxillofacial fractures (MF). Age, gender and trauma mechanism correlated with THI were also investigated. Patients and Methods: We conducted a hospital-based retrospective case–control study at Stomatology College and Hospital, Wuhan University. From January 2000 to December 2009, a total of 1131 patients with MF were enrolled in the statistical study to evaluate the association of THI and other risk factors with MF. Among these patients, 86 presented with THI. We utilized binary logistic regression and risk analysis to investigate the associations among MF and other risk factors with HI. Results: Head injuries (103 injuries) were sustained by 86 patients (7.6%), with male-to-female ratio of 4.1:1.0. Most of the patients (52 patients, 50.5%) also exhibited cranial bone fractures. The age group with most patients was the 30–39 years age group (26 patients, 30.2%), followed by the 19– 29 years age group (22 patients, 25.6%). Motor vehicle accident (MVA) was the most common mechanism of injury (49 patients, 74.1%). Patients older than 50 years showed the highest risk for head injury (OR, 2.0; 95% confidence interval, 1.1–3.7; P = 0.025). MVA had a sixfold risk of head injury (OR, 6.2; 95% confidence interval, 1.5–26.1; P = 0.013). Head injuries were more prone to occur in patients who had combined fracture of the mid-face and mandible (OR = 4.6, P < 0.001), and only a 0.3-fold risk of multimandible fractures (P < 0.001), 0.5-fold risk of single mandibular fracture (P = 0.017) and 0.3-fold risk of patients who sustained only single mandibular condylar fracture (P = 0.019). Conclusions: The occurrence of head injuries is significantly related to age, aetiology and the pattern and position of maxillofacial fractures.
Patients with maxillofacial fractures (MF) may also suffer from traumatic head injuries (THIs) because of the close anatomic proximity of the facial bone and cranium (1–5). Previous studies have revealed that MF are usually associated with THI, and various incidences of THI (5.4–45.5%) have been reported (1, 5–10). A study based on the National Trauma Data Bank (NTDB) in the US showed a high incidence of patients with MF who also suffered from THI (67.9%) (11). The more serious the MF are, the higher (86%) the probability of occurrence of THI (12). However, researchers have different opinions with regard to the relationship between MF and THI. Some researchers speculate that the facial bone absorbs the energy of the impact, protecting the brain from injury (13, 14). Other researchers believe that high-velocity impacts with sufficient force to break facial skeletons may also cause serious head injuries, such as intracranial haemorrhages (15–17). Haug et al. refuted theories stating that facial © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
bones act as cushions to protect the cranium and its contents (4). Keenan et al. found that the risk of serious intracranial injury in patients with facial trauma increased by almost tenfold (18). To reduce mortality and morbidity and to improve the outcome of treatments in patients with MF, early detection of associated THI remains an important procedure among patients with MF (5, 18, 19). A number of retrospective studies have been conducted to investigate the correlation between THI and MF. Despite some controversial reports, it has been suggested that THI is associated with MF. Nevertheless, multiple factors and potentially significant confounding variables result in difficulty in obtaining the accurate assessment of the relationship between THI and MF. The previous studies on this subject vary in the selection of populations, sample sizes, methodology and analysis results. Therefore, it is necessary to further delineate the involvement of THI, together with other related risk 1
2
Zhou et al.
factors, in MF with large sample size and strict analysis methodology. In this study, we conducted a hospital-based case– control study to analyse and evaluate the correlation between THI and MF. The occurrence of THI in relation to age, gender, trauma mechanism and type of MF was also investigated. We hypothesized that the THI is related to the pattern and position of the MF. We also hypothesized that the occurrence of THI is influenced directly by the energy directed by external force, the high external force in high-velocity accidents (motor vehicle accidents) leading to the higher probability of THI in patients with MF. We additionally hypothesized that older adults would be more susceptible to THI relative to young controls. Materials and methods Ethics statement
We conducted a hospital-based retrospective case–control study at Stomatology College and Hospital, Wuhan University, from January 2000 to December 2009. The protocol, survey forms and consent forms were approved by the Institutional Review Board (IRB) of Wuhan University. Written consent given by the patients was waived by the approving IRB. Study population and data collection
Patients with MF admitted in the Department of Oral and Maxillofacial Surgery, Stomatology College and Hospital, Wuhan University from January 2000 to December 2009 were enrolled in this study. Patients were excluded as study subjects based on the following: (i) repeated admissions and (ii) incomplete information. In total, 1131 participants had complete diagnostic records with MF. Information and data, which included age, gender, mechanism of injury, type of MF and type of THI, were collected and standardized by an investigator based on the patients’ case histories, clinical and radiographic examinations and medical records. Initial cranial CT was performed in all patients with neurological abnormalities, impaired consciousness or clinical signs of skull fracture, which were further diagnosed by a radiologist. Therefore, the neurological data in this study were based on the information obtained from historic diagnoses (who had ever admitted and diagnosed in the department of neurosurgery of other hospitals), clinical and CT examinations. The mechanisms of injury were classified as assault, road traffic accident [motor vehicle accident (MVA), motorcycle accident and bicycle accident], fall (at ground or high levels), sports- or work-related accident and others. MFs were categorized as exclusively mid-facial fractures (multiple or single), combined fractures of the mid-face and mandible, multiple mandibular fractures and single mandibular fracture (symphysis, condyle, body, angle, ramus, coronoid or alveolar fracture). The type of THIs was grouped according to cranial bone fractures (basal skull, frontal, temporal, occipital sphenoid and other skull fracture), intracranial problems
(cerebral contusion, pneumocephalus, epidural haematoma, subdural haematoma, subarachnoid haemorrhage, intracerebral haematoma, intracranial haemorrhage and cerebrospinal fluid leakage), concussion (patients with loss of consciousness without signs of intracranial haemorrhage were diagnosed with concussion) (18) and other injuries (traumatic brain injury, open brain injury, scalp laceration and scalp haematoma). The patients were grouped into 0–9, 10–19, 20–29, 30– 39, 40–49 and 50 years and above (only three patients in test group were older than 60 years; therefore, we combine the patients in the group 50 years and older. Case group and control group
Among the patients with MF, 86 patients diagnosed with THI were used as the case group. Other patients (1045 patients) with MF but without THI were used as the control group. Statistical analysis
Statistical analysis was performed using SPSS software (version 16.0; SPSS, Chicago, IL, USA). Continuous variables were reported as mean SD and were assessed by independent samples t tests as necessary. The two-tailed nonparametric Mann–Whitney U-test was used when variances were not equal among series. The chi-square test was used to compare categorical variables. Fisher exact test was utilized when observation in any cell of the 2 9 2 table was expected to be less than five. Odds ratio and 95% confidence interval were used to assess the risk of sustaining head injuries. Logistic regression analysis was used to control confounding variables. Probabilities of P < 0.05 were considered to be significantly different. Results Incidence of THI following MF
In the 10-year period of this study, 1131 patients with MF were registered and analysed, with male-to-female ratio of 3.5:1.0 (881 men and 250 women). Among these 1131 patients, 7.6% (86 patients) presented with associated THI, with male-to-female ratio of 4.1:1.0 (69 men and 17 women). The age range of the patients associated with THI was 4–70 years (average 34.5 13.6 years). The age group with the most patients was the 30– 39 years age group (26 patients, 30.2%), followed by the 20–29 years age group (16 patients, 18.6%). In this sample, MVA was the most common mechanism of injury (49 patients, 74.1%), followed by motorcycle accidents (12 patients, 14.0%), falls (12 patients, 14.0%) and assault (seven patients, 8.1%) (Table 1). We observed that 50.5% of the patients (52 patients) with THI sustained cranial bone fractures. The most common site of cranial bone fractures was the base of the skull (20 patients, 19.4%), followed by the frontal bone (17 patients, 16.5%) and temporal bone (six patients, 5.8%) (Table 2). Thirty-six patients (35.0%) sustained intracranial problems. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Traumatic head injuries in maxillofacial fractures
3
Table 1. Logistic regression analysis: risk of head injuries in patients by age, gender and aetiology THI
Sex Male Female Age Aetiology Assault Bicycle MVA Fall ground Fall high Motorcycle Sport Work
Present n (%)
Absent n (%)
Significance (Crude)
69 (80.2) 17 (9.8) 34.5 13.6
812 (77.7) 233 (22.3) 30.8 13.4
7 (8.1) 3 (3.5) 49 (57.0) 2 (2.3) 10 (11.6) 12 (14.0) 0 1 (1.2)
152 64 300 134 111 167 20 26
(14.5) (6.1) (28.7) (12.8) (10.6) (16.0) (1.9) (2.5)
Odds ratio (adjusted)
95% CI
Significance (adjusted)
0.587
1.1
0.6–1.9
0.751
0.013
1.0
1.0
0.009
0.100 0.320
