| Diplopia and enophthalmos were the most characteristic manifest for orbital fracture patients. To date, these patients were diagnosed and treated mostly by doctors working in the maxillofacial surgery, plastic surgery and otolaryngology department and therefore the classifications of orbital fractures were formed on the basis of viewpoints hold by these non-ophthalmologists. so there were few detailed, systemic and directed clinical data that evaluated extraocular muscle function changes of orbital blowout fracture patients from the view of ophthalmologists. In this paper along with our new subtype classification system introduced, the relationship between the location as well as morphology of the fractures and extraocular muscle function changes for orbital blowout fracture patients were studied and discussed which could provide more referenced opinions for operation method choice and observing patients prognosis. During the 3 years from March of 2002 to January of 2005, 187 patients(144 men and 43 women) were diagnosed as orbital blowout fracture. Mean age was 29.7 years(range, 5 to 65 years). The mean delay time between the day of injury and coming to hospital was 23.6 days (range, 1day to 5 months). Hertel exophthalmometry was used for measurement of enophthalmos and extraouclar muscle functions was investigated by candle double vision test and synoptophore. All the patients were evaluated by axial and coronal computed tomography scans, necessarily carried with three-dimension CT construction to confirm the clinical diagnosis. Isolated medial orbital fracture and inferior orbital fracture were classified to the subtypes respectively according to the location and morphological characteristics of the fractures. Type I medial orbital fracture was defined as that the whole ethmoid was comminuted broken and depressed, ethmoid sinus disappeared and its original spaces were filled with fat tissues . The curvature and replacement of medial rectus muscle was obvious on CT scaning images. Type II medial orbital fracture was defined as the partial ethmoid fractured with ethmoid sinus mostly intact, but a morphologically angle-like image was formed between the fractured fragment of orbital wall and the ambient connective tissue around medial rectus muscle which could be wedged into the fracture area. Type I inferior orbital fracture was classified as that the large area of inferior orbital wall between infraorbital fissure and ethmoidomaxillary fissure was broken and orbital content was entraped into maxillary antrum. Type II inferior orbital fracture was quantified as that the area around infraorbital groove in the front of inferior orbital wall with broken fragment sloped into maxillary antrum, but the nasal edge of fragment was joined with inferior orbital wall and the connective tissue around inferior rectus musclewas similar with type II medial orbital fracture wedged into the fracture area. The criteria to analyze extraocular muscle function changes were as follows. (1) Crossed diplopia can be the major sign as paralysis of medial rectus muscle which could be determined by turning patients'injured eye medially. And the distance between object and double vision image was more significant by using candle double vision test technique. Besides exotropia degree was found increased by synoptophore test. (2)Restriction of medial rectus muscle would let patients show accompanying same side diplopia when patients turned the involved eye laterally. And the distance between object and image become more obvious by using candle double vision test. Besides esotropia degree was increased by using synoptophore test. (3) Inferior diplopia could occur as the sign of paralysis of inferior rectus muscle when patients turned the involving eye lateral inferiorly to 15 degree. And the distance between object and image was further increased by using candle double vision test and vertical separated diplopia could be more significant when tested by using synoptophore and the involving eye position was higher than the opposite eye. (4)When patients turned the involved eye lateral superiorly to 15 degree, the superior diplopia could occur as the sign of restriction of inferior rectus muscle and the distance between object and image was further apart by candle double vision test with increased vertical separated diplopia while using synoptophore and the involved eye position was inferior to the opposite eye. (5)The sign for paralysis of inferior oblique muscle was the accompanying vertical diplopia when patients turned the involved eye medial superiorly to 15 degree. And the distance between object and image was largerwhen candle double vision test was applied. Besides vertical separated degree of diplopia was increased maximally by using synoptophore and the involved eye position was inferior than the other eye. All data were analyzed statistically by SPSS bag 11.0. Major symptoms of Orbital blowout fracture patients are diplopia(135,72.2%)and enophthalmos(103,55.1%). There were 28 persons with enophthalmos(mean difference between 2 eyes 2.98±0.71 mm)and 13 persons with diplopia in 35 type I medial orbital fracture patients. Among 47 type II medial orbital fracture patients there were 6 enophthalmos (mean difference between 2 eyes 2.25±0.42mm) and persons with 29 diplopia. The incidence and severity of enophthalmos in type I medial orbital fracture patients were higher than that in type II(Z=-6.075, P<0.05;t=3.365, P<0.05) and the incidence of having diplopia was lower in type I medial orbital fracture than in type II(Z=-2.187, P<0.05). In cases of type I medial orbital fractures, the paralysis of medial rectus muscle was the most frequently seen(14/20) phenomenon with fewer cases of medial rectus muscle restriction (2/20) and the simultaneous presence of both paralysis and restriction of medial rectus muscle also occurred in 4 out of 20 cases. There were more restriction cases (27/38) and less paralysis (5/38) of medial rectus muscles among type II medial orbital fracture patients. 6 patients had both paralysis and restriction change of medial rectus muscles. Comparing type I with type II medial orbital fracture groups, the incidence of medial rectus muscle palsy was higher in the former group (Z=-4.346, P<0.05) but with lower rate of medial rectus muscle restriction (Z=-4.382,P<0.05).Meanwhile there was no statistical difference(Z=-0.400,P>0.05) between the occurrence of simultaneous paralysis and restriction of medial rectus muscles in these two groups. There were 6 cases of enophthalmos (mean difference between 2 eyes 2.58±0.47 mm) and 13 diplopia persons were found in 18 type I inferior orbital fracture patients. 5 enophthalmos(mean difference between 2 eyes 2.10±0.24mm) and 18 diplopia occurred respectively in 26 patients in type II inferior orbital fracture. There were more cases with higher severity of enophthalmos in type I inferior orbital fracture than that in type II group (Z=-3.141,P<0.05;t=2.873,P<0.05) and with no difference in term of diplopia occurrence between the two subtypes (Z=-2.11,P>0.05). The paralysis of inferior rectus muscle was more frequently seen (10/18) in type I inferior orbital fracture patients. with less restriction changes(4/18). And 4 of 18 patients had both inferior rectus muscle paralysis and restriction simultaneously. Within type II inferior orbital fracture patients, there were 14 of 26 cases having restriction and 2 out of 26 cases with paralysis of inferior rectus muscles. Simultaneous paralysis and restriction of inferior rectus muscles happened in 5 out of 26 patients. The paralysis of inferior rectus muscle mainly appeared in type II inferior orbital fractures (13/18).So comparing type I with subtype II of inferior orbital fractures, the rate of inferior rectus muscle palsy was higher in type I than in type II (Z=-3.065, P<0.05),but with less inferior rectus muscle restriction in type I (Z=-2.740,P<0.05).There was no statistical difference (Z=-0.116, P>0.05)of simultaneous paralysis and restriction of inferior rectus muscle in these 2 subtypes. There were 55 and 57 patients out of 61 with enophthalmos(mean difference between 2 eyes 3.35±0.64 mm) and diplopia respectively in the complexed medial inferior orbital fracture group. Comparing with the former mentioned two isolated blowout fracture types, 42 patients with enophthalmos (mean difference between 2 eyes 2.85±0.72mm) and 34 with diplopia appeared in total 82 medial orbital fracture group; 17 patients with enophthalmos (mean difference between 2 eyes 2.44±0.46mm)and 31 diplopia in a total 44 within inferior orbital fracture group.Either severity or number of enophthalmos and diplopia were higher in medial inferior orbital fracture patients than those isolated medial or inferior orbital fracture groups statistically(P<0.05). Combined effect of more muscles involved in the medial inferior orbital fractures make the changes of the extraocular muscle functions more complicated to be analyzed according to a sole examination method. With the above studies and anlysis, the following conclusions were shown bellow: Clinical manifest of orbital blowout fracture patients was mainly diplopia and enophthalmos. The paralysis of medial rectus muscle was predominant in type I medial orbital fracture and with the results for more restriction changes in type II. The incidence and severity of enophthalmos were higher and obvious in type I medial orbital fracture than in that of type II medial orbital fracture. However, less patients with diplopia were found in type I than in type II. More inferior rectus muscle paralysis were present in type I inferior orbital fractures in comparison with the restriction changes of extraocular muscle functions in II type and interestingly the paralysis of inferior oblique muscles were found more in type II. |
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