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Results |
The upper midface area comprises mainly the naso-orbito-ethmoidal (NOE) region which plays a paramount role in facial expression. Fractures of this area often result in neglected bony defects in the fragile periorbital region with major secondary impairments such as traumatic telecanthus, orbital dystopia, and/or enophthalmos. Permanent cranial nerve deficits also can occur as the result of post-traumatic/post-operative sequelae. Seventy-one patients (age range 7-78 years) with severe high midface trauma, treated from January 1989 to December 1996, were reviewed with a minimum follow-up of 2 years. The patient population has been distributed according to the fracture type in three groups: Group 1 (n=35): Isolated NOE with/without associated central midface injury; Group 2 (n=22): NOE associated with craniofacial injury and Group 3 (n=14): NOE associated with orbital displacement. The estimated post-surgical parameters included qualitative and quantitative data from the long-term clinical evaluation. Persistent headache and/or concentration difficulties were mainly noted in Group 1. Smell reduction or anosmia was reported mainly in Group 2. Deficits of the trigeminal and/or the facial nerve were found in Group 3. Enophthalmos and/or telecanthus were predominantly seen with injuries associated with orbital displacement.
Keywords: Naso-orbito-ethmoidal, sequelae, trauma
J.R.Coll.Surg.Edinb., 45, December 2000, 359-362
The diagnosis and treatment of severe high midface injury remains one the most challenging areas in facial trauma reconstruction due to the anatomical complexity of the nasoorbito-ethmoidal (NOE) region and its paramount role in facial expression. Inadequate or unnecessarily delayed repair result in severe cosmetic deformities and functional losses that are often difficult or impossible to correct secondarily.
The main factors determining the management of high mid-face fractures are the type of fracture (isolated or extended), associated bone and soft tissue injury and bone loss or presence of non-functional bone.1 It is almost unanimously accepted that the treatment modalities should include: (1) early surgical exploration, (2) wide exposure of the fractured area via a coronal approach, (3) identification of the extent and type of the fracture pattern, (4) meticulous anatomical bone fixation, utilizing principles from craniofacial surgery and rigid fixation techniques with (5) specific attention to naso-orbital soft tissue reconstruction.2 In addition, injury to adjacent structures such as the frontal sinus or even the skull base, with concomitant cranio-cerebral lesions, is frequently a confounding factor in these complex trauma cases. These features necessitate a procedure which guarantees a water-tight separation of the brain after reconstruction of the anterior skull base and consequent obliteration of the frontal sinus.3,4 Significant bone loss or, more commonly, the presence of severely comminuted bone fragments, will require primary bone grafting to restore structural integrity and prevent soft tissue contracture.5 Inevitably, even though bony defects and/or soft tissue disposition cannot be primarily excluded, due to several factors such as insufficient reconstruction of the comminuted medial orbital wall and the loss of distal nasal support in the perpendicular plate of the ethmoid,5,6 late impairments still occur, emphasizing the need for initial meticulous treatment.7 Traumatic telecanthus, enophthalmos, diplopia, zygomatic asymmetry, nasal bone disfigurement and nerve deficits are the most common late derangements after high midface injury.8,9
The type, incidence and classification of the persistent post-traumatic/post-operative sequelae after treatment of high midface trauma, is the subject of this study. The aim is a better understanding of the potential late sequelae which may lead to a more precise therapeutic plan and, consequently, an improvement in surgical outcome.
Seventy-nine patients with fractures in the high midface area were treated surgically in the Department of Maxillofacial Surgery of the University Hospital of Zurich between January 1, 1989 and December 31, 1996. Seventy-one of these patients were reviewed with a minimum follow-up time of 2 years. The patient population consisted of 55 (77.5%) males and 14 (22.5%) females. The age range was 7-78 years. The mean age at operation was 35.1 years. To allow a reliable statistical analysis the patient population was distributed into three main groups: Group 1 (n=35): Isolated NOE; Group 2 (n=22): NOE associated with cranio-facial injury, and; Group 3 (n=14): NOE associated with orbital displacement.
LONG-TERM POST-OPERATIVE EVALUATION
The post-surgical parameters measured included qualitative and quantitative data from the long-term clinical evaluation. Qualitative parameters concerning persistent headache, migraine, concentration difficulties and cranial nerve (I, V, VII) deficits were graded as low, moderate or severe. Quantitative data included the presence and evaluation of traumatic telecanthus and enophthalmos. Traumatic telecanthus was calculated by the canthal index formula defined as the ratio of inner canthal distance to outer canthal distance multiplied by 100.10 Enophthalmos, which is defined as a reduction in the balance of the orbital contents and orbital volume, was judged to be present when the difference in the anteroposterior projection between the two globes was greater than 2 mm. The measurement was performed using the Helter exophthalmometer. Subsequently, all data was submitted for statistical analysis using the Anova, Kruskal-Wallis and Chi-Square tests.
Demographic Data
Almost half of the NOE injuries were sustained by young males. The main causes in this age group were related to road traffic accidents or interpersonal violence. The frequency of fractures distributed according to age groups is presented in Table 1.
Table 1: Incidence of fractures and age distribution
| Age(From(>)To(<)) | Number | Percentage |
|---|---|---|
| 0.1-10.0 | 5 | 7.04 |
| 10.1-20.0 | 9 | 12.68 |
| 20.1-30.0 | 20 | 28.17 |
| 30.1-40.0 | 15 | 21.13 |
| 40.1-50.0 | 10 | 14.09 |
| 50.1-60.0 | 7 | 9.86 |
| 60.1-70.0 | 2 | 2.82 |
| 70.1-80.0 | 3 | 4.23 |
Post-operative Sequelae
Qualitative Data
Twelve (17%) patients presented with persistent headache, frontal pain and concentration difficulties Nine (75%) of these patients had sustained combined NOE and cranio-cerebral injury (Group 2). Two (17%) of the cases were categorized in Group 3 and one (8%) patient as Group 1. The severity of the pain was characterized as low or moderate in nine of the cases, whereas in the other three the pain was associated with concentration difficulties and medication was required regularly.
Thirty-three (46.5%) patients complained of loss of smell. Low degree derangement was found in five (7%) patients, moderate in 10 (14%), and severe in eighteen (25.4%) of our patient population. In the latter, three (4.2%) patients with anosmia were included. Loss of smell was strongly correlated with Group 2 fractures (chi-square test: p<0.001). Eighteen (81.8%) of the twenty-two patients in this Group complained of significant smell disturbance (Figure 1).
Figure 1: Group distribution and disturbances of the olfactoryl nerve
Hypo-, para- or even anaesthesia of the trigeminal nerve was demonstrated in twenty-four (33.8%) patients. The distribution involved eight (22.8%) patients from Group 1, eight (36.4%) from Group 2 and eight (57.1%) from Group 3. Four (16.7%) of the twenty-four patients presented with anaesthesia of at least one branch of the trigeminal nerve. The first branch was involved in one patient and the second branch in the other three patients. Although those deficits of the trigeminal nerve presented more frequently in patients with NOE injury extending into in the lateral midface (57.1%), there was no statistically significant difference between the three groups of patients (Figure 2).
Figure 2: Group distribution and disturbances of the trigeminal nerve
Ten (14.1%) patients presented with weakness of the facial nerve; in none of the patients was there complete paralysis. The distribution included two (5.7%) patients from Group 1, three (13.6%) and five (35.7%) from Group 2 and 3, respectively. The increased incidence in Group 3 was found to be of statistical significance (p<0.05) (Figure 3).
Figure 3: Group distribution and disturbances of the facial nerve
Quantitative Data
The calculation of the canthal index (CI) was considered positive for severe post-traumatic telecanthus when the CI>38.10 Ten (14.1%) patients presented with clinically significant telecanthus. Although there was an increased incidence of telecanthus amongst patients in Groups 2 and 3, the difference was not statistically significant. Table 2 and Figure 4 demonstrate the results obtained amongst the three groups of patients studied.
Table 2: Post-traumatic telecanthus after calculation of the canthal index
| Groups | Number | Mean | Std. Dev. | Std. Error |
|---|---|---|---|---|
| Group 1 | 35 | 34.77 | 2.07 | .35 |
| Group 2 | 22 | 36.09 | 3.53 | .753 |
| Group 3 | 14 | 36 | 3.76 | 1.005 |
(std. dev=standard deviation, std. error=standard error; one factor Anova test)
Figure 4: Group distribution and post-traumatic telecanthus
Post-traumatic enophthalmos was confirmed in twenty-eight (39.4%) patients. Six (17.1%) patients were in , nine (40.9%) in Group 2 and thirteen (92.3%) in Group 3.
Nevertheless, clinically significant enophthalmos (>3mm) was documented in thirteen (18.3%) patients. Figure 5 illustrates the group distribution and the statistical results between the three groups (Kruskal-Wallis test: p<0.01).
Figure 5: Group distribution and post-traumatic enophthalmos
Surgical treatment of high midface injuries poses one of the most demanding tasks in maxillofacial trauma due to the anatomical complexity of the orbito-nasal framework. This may often lead to aesthetic or even functional impairments which compromise the desired surgical outcome. Problems occurring after treatment of high midface trauma are related either to tissue displacements in the fragile periorbital region, cranial nerve deficits or even poor performance status due to episodes of migraine associated with concentration difficulties.11
Persistent frontal pain or headache (when operative traumatic neuralgia does not exist) in patients treated for severe NOE trauma always poses a clinical dilemma. In our series this was mainly seen when concomitant cranio-cerebral injury was present. A vascular background to this chronic headache syndrome has been suggested and regimens for symptomatic treatment with the use of ergotamine preparations and adrenergic blocking agents have been reported.12
Anosmia which is an occasional sequela to high midface fractures can result from a shearing action of the olfactory nerve against the cribriform plate or direct laceration/ disruption of the fila olfactoria.13 Van Damme and Freihofer (1992) found a high propensity (>50%) for disturbances of smell and taste after high midface fractures.14 Varney (1988) reviewed 64 patients who had sustained head injuries and documented post-traumatic disturbances of smell.11 More than half of these cases were totally anosmic with severe impairment of neuropsychological status. Our results are in agreement with these findings. The statistically significant propensity for anosmia in the group of patients with combined NOE and base of the skull fractures (80%) emphasizes the association between skull base fracture and direct laceration of the fila olfactoria.
Impairment in sensitivity of the trigeminal nerve (mainly infraorbital branch) was confirmed in twenty-four (33.8%) patients. Although statistically no significant difference has been shown, there is an increased incidence of nerve deficits in cases of involvement of the lateral midface (Group 3). This correlates well with the results of other studies. Bergler et al (1997) reported persistent dysaesthesia of the infraorbital nerve in 32.4% of their patients after treatment of central and lateral midface fractures.7
Deficits of the facial nerve after NOE trauma involved mainly the buccal branch (though in two patients the frontal branch was involved) and resulted from direct injury of the facial nerve during the initial trauma. The latter was confirmed by the increased incidence in Group 3 which involved complex NOE trauma associated with injury of the lateral midface.
Telecanthus may result from improper transnasal reduction of the canthus-bearing central bone fragments. Clinically, evidence of post-traumatic telecanthus was documented in 14.1% of the patients in our study groups. A late increase in the intercanthal width suggests that fixation of the medial canthal ligament was inadequate in some cases (especially in cases treated with canthopexy wiring). An even further reduction of the post-surgical intercanthal distance seems to be desirable. This can be achieved with more adequate reconstruction of the bony segments and probably with the use of micro-plate fixation in the medial canthal region.2
Traumatic enophthalmos is the most common residual deformity in complex orbital injuries. The underlying cause is a discrepancy between the volume of the bony cavity and its contents. The intraorbital soft tissue envelope may diminish in volume, as a result of atrophy or displacement of fat from within the intramuscular cone, cicatricial retraction of the ocular muscles, or entrapment of the supporting ligament system.5,15 In the present study, thirteen (18.3%) of the patients developed clinically significant post-traumatic enophthalmos (difference in antero-posterior projection >3mm). This affected mainly patients with severe orbital displacement caused by high-velocity trauma associated in most of the cases with comminution or defects of the medial orbital wall. Direct visualization of all periorbital walls and reconstruction even of the deep aspect of the orbital cavity seem to be the key to the prevention of this residual deformity.16
In summary, high midface trauma associated with cranio-cerebral injury has an increased incidence of post-traumatic "persistent frontal pain syndrome", anosmia and telecanthus. High midface trauma, with involvement of the central and lateral segments of the midface, leads to an increased incidence of trigeminal and facial nerve disturbance and of post-traumatic telecanthus and/or enophthalmos.
Copyright date: 3rd September 2000
Correspondence: N.D. Kalavrezos, Maxillofacial Surgery Department, Royal London Hospital, Whitechapel E1 1BB, London U.K.
©2000 The Royal College of Surgeons of Edinburgh, J.R.Coll.Surg.Edinb. 45, 6: 359-362