- Email: [email protected]
Traumatic defects of the orbital floor
British Journal of Oral Surgery (1972.), IO, 133-142.
T R A U M A T I C D E F E C T S OF T H E ORBITAL FLOOR A. S. DAVIES,B.D.S., H.D.D, F.D.S.
Plymouth General Hospital
TRAUMATICorbital floor defects have been recognised since Lang (1889) reported a case of 'traumatic enophthalmos', which had been caused by a blow to the globe. Pfeiffer (1943) and Converse and Smith (I95O), described indirect fractures of the orbital floor, the latter introducing the term 'blow-out' to indicate those fractures of the floor in which the orbital rim remained intact. Such injuries are not uncommon. Cramer et al. (1965) found 64 (53"7 per cent) orbital floor defects in 119 fractures of the middle third of the face and Freeman (1962) reported that 26 (33 "7 per cent) of 77 cases with fractures of the zygomatico-maxillary complex had significant defects in the orbital floor. Several authors have outlined the diagnosis and management of these injuries, and mainly those writing in the American literature have emphasised the necessity for early operative intervention to prevent enophthalmos and persistent diplopia (Converse & Smith, 195o; Freeman, 1962; Cramer et al., 1965). Those surgeons dealing with maxillo-facial injuries are familiar with orbital anatomy, but it is pertinent to repeat that the floor is extremely thin, being thinnest medial to the infra-orbital groove and canal. As every fracture of the zygomaticomaxillary complex involves the orbital floor, the latter is frequently comminuted and leaves a defect. Such defects, if untreated, may result in enophthalmos and persistent diplopia due to atrophy of herniated orbital fat and interference with extraocular muscles. This paper describes a study in which the incidence of orbital floor defects in patients who had sustained facial injuries was assessed. It emphasises certain points in the diagnosis of these defects and outlines the active management. A standard operative approach is described, and a review is reported of cases in which Silastic sheeting was used to reconstitute the floor.
M A T E R I A L S AND M E T H O D S At Plymouth General Hospital 238 consecutive cases of facial trauma (includ~ ing soft tissue without bony injury) were studied over a period of I4 months. T h e study was, in part, retrospective and not all cases were treated personally. The presence of orbital floor defects is determined on the basis of history, clinical examination, radiography and operative findings. Of particular value in the clinical examination, is the presence of limited excursion of the globe with associated diplopia on upward and outward gaze (Fig. I). This suggests tethering of the inferior rectus muscle and makes operative exploration obligatory. Although, in theory, enophthalmos should be present due to the herniation of the orbital fat into the maxillary sinus, this may be obscured by the coincident periorbital oedema and ecchymosis. Standard I5 ° and 300 occipitomental views will demonstrate the clinically 133
134
BRITISH JOURNAL OF ORAL SURGERY
FIG. I Limited excursion of right globe on upward and outward gaze.
FIG. 2
FIG. 3
Fig. 2 . - - ' H a n g i n g drop' appearance of herniated orbital contents in left maxillary sinus. Fig. 3---View to demonstrate displacement at the zygomatico-frontal suture.
FIG. 4
FIG. 5
Fig. 4.--Blow-out fracture demonstrated on coronal plane tomography. Fig. 5.--Blow-out fracture demonstrated on sagittal plane tomography.
T R A U M A T I C DEFECTS OF THE O R B I T A L F L O O R
135
displaced fracture of the zygomatico-maxillary complex and a 'blow-out' shows cither as an opacity of the maxillary sinus or occasionally as the pathognomonic 'hanging drop' sign, produced by the herniating orbital contents (Fig. 2). However, the displacement of the complex at the zygomatico-frontal suture is the key to the management of the fractured malar and this may bc difficult to see on standard views. The Radiography Department in Plymouth General Hospital has evolved a view which shows the suture more clearly (Fig. 3) (Brandrick & TurnbuU, 1972). In those patients in whom the presence of an orbital floor defect is suspected, coronal orbital tomography is performed. Difficulties may be experienced in interpreting these films, especially if deviation from a true coronal plane has rcsultcd in apparent asymmetry of the orbital floors. However, thc defect can be clearly demonstrated (Fig. 4), and, certainly, coronal tomography is more helpful than sagittal plane tomography which is even more difficult to interpret (Fig. 5).
FIG. 6 FIG. 7 Fig. 6.--Reduction of zygomatico-frontal suture fracturevia eyebrow incision. Fig. 7.--Traction or forced duction test. • Surgical exploration is undertaken in patients in whom an orbital floor defect is suspected. In all malar fractures requiring elevation, the complex is approached through an eyebrow incision as opposed to the Gillies temporal approach (Gillies et al., I927). This exposure allows reduction of displacement at the zygomaticofrontal suture under direct vision (Fig. 6), and wiring can be undertaken in unstable fractures without further skin incision. An infra-orbital incision is made in cases with comminuted or unstable inferior orbital margins which are then wired, and also in cases where an orbital floor defect is suspected. When there is no apparent reason to make this incision, the traction or forced duction test is performed by grasping the insertion of the inferior rectus muscle through the conjunctiva of the lower fornix with fine toothed forceps (Fig. 7). Any restriction in upward movement, which can be compared with the normal side, suggests muscle tethering and indicates exploration. The skin is incised in a natural crease line, and the dissection carried down to the inferior orbital margin by splitting the orbicularis oculi fibres. The periosteum is incised just below the margin and elevated to expose the orbital floor. A broad blunt retractor supports the orbital contents while orbital tissues, which
136
BRITISH JOURNAL OF ORAL SURGERY
have passed through the floor defect, are gently teased upwards. Particular care is taken to ensure that the inferior rectus and inferior oblique muscles are freed from the edges of the defect. Any loose bony fragments are removed, and the defect is covered by a 0. 5 mm-I mm thick sheet of Silastic (cut to a triangular shape to avoid pressure on adjacent structures) which should be supported by sound orbital floor remains (Figs. 8A, 8B). The traction test is repeated to confirm that any muscle tethering has been released, and the pcriostcum is then carefully sutured to avoid extrusion of the implant. The wound is closed in layers.
FIG. 8 A, Insertion of Silastic orbital floor implant. B, Position of Silastic orbital floor implant.
In this series 5o Silastic implants were placed over orbital floor defects, 39 of them by the author. RESULTS It can be seen from Table I that of the 238 cases studied, 25.2 per cent were malar fractures, 5"9 per cent were 'blow-outs' and 5"4 per cent were Le Fort II and III fractures. The remaining 64. 5 per cent included soft tissue lacerations, mandibular and nasal fractures. 2I. I per cent of the total had orbital floor defects occurring as shown. Of the malar fractures, 46"6 per cent showed significant defects which also occurred in 6I. 5 per cent of the admittedly small number of Le Fort II and III fractures (Table II). Since pure 'blow-out' fractures classically occur after a single blow to the globe, the injuries in 89 patients presenting with a unilateral black eye, were evaluated (Table III). Of these, 28 (31"5 per cent) had an orbital floor defect
TRAUMATIC
DEFECTS
OF T H E
ORBITAL
FLOOR
I37
associated with a malar fracture, while 14 (I5"7 per cent) were pure 'blow-outs'. Orbital floor defects therefore occurred in 47..2 per cent of black eyes. A calculation of the accuracy of pre-operative diagnosis showed that this was 77"8 per cent in defects associated with malar fractures and 60"9 per cent in pure 'blow-outs' (Table IV). TABLE I Incidence of middle third fractures and orbital floor defects in 238 cases of facial trauma (25. I2. I969-11.3. I97 I)
30
-
Malar Fracture 25-2 % Total
Total Number of Defects
20 -
2I'I
IO
-
Malar Fracture + Defect Ii'8 Le Fort II &llI 5.4
Le Fort II & III + Defect 3"4
Pure Blow-out 5,9
The post-operative evaluation of the 39 personal Silastic implants are shown in Table V. The longest period for which an implant had been in place was 29 months, the shortest 14 months, with a mean of 2I months. One implant was removed as it presented subcutaneously IO months after insertion. Since there was no evidence of an inflammatory reaction, it is probable that the periosteal closure had been inadequate. One patient had persistent diplopia and enophthalmos six months after multiple intra-osseous wiring of a severely comminuted fracture of the zygomatico-maxiUary complex and the insertion of a large Silastic
138
BRITISH
JOURNAL
OF O R A L S U R G E R Y
implant. Augmentation of the floor support was considered, but on ophthalmic examination, no diplopia was found after one year. No persistent diplopia occurred in the untreated cases, though enophthalmos was found seven days after injury, in one patient who refused treatment for a 'blow-out'. TABLE I I Incidence of orbital floor defects in malar and Le Fort fractures 7°
-
60 Malar Fracture 60 5°
Number of Cases
-
% Incidence in Malar Fractures = 46-6 % Incidence in Le Fort Fractures = 61"5
40
3o Malar Fracture + Defect 28
20
IO
Le Fort II & III 13
-
Le Fort II & III + Defects 8
DISCUSSION Probably the paramount aim in the treatment of fractures involving the orbit is the prevention of persistent diplopia. Diplopia is frequently encountered in those patients who have a significant defect in the orbital floor and especially in those in whom the inferior oblique or inferior rectus muscle has become tethered to the bony fragments. T h e incidence of such defects is high, and in this series higher than previously reported. T h e presence of a small defect does not necessarily result in diplopia as
TRAUMATIC DEFECTS OF THE ORBITAL FLOOR
I39
evidenced by the lack of this symptom in the cases not surgically explored. However, where a defect of sufficient size is suspected on clinical and radiographic grounds, exploration of the orbital floor is justifiable. Primary exploration is a simple quick procedure, especially if the orbital rim is being wired. Operative exploration is further supported by the fact that in many cases bony spicules from TABLE III % Incidence of orbital floor defects in 89 unilateral black eyes
7 °
60
% Total
-
-
Malar Fracture 67-4
5o -
40
-
30
-
20
--
IO
-
Total Defect 47"2 Malar Fracture + Defect 3r'5
Pure Blow-out I5"7
Soft Tissue Injury I6"85
the thin orbital floor were found lying in a vertical position. This was most frequently seen in those cases in which there had been wide separation of the zygomatico-frontal suture and medial displacement of the malar complex, i.e., a Class V fracture (Knight & North, I96I). Compression of the orbital floor will rotate the fragments into the vertical position in which they probably remain even after reduction of the fracture. They may cause injury to any of the orbital K
BRITISH JOURNAL OF ORAL SURGERY
140
contents or may provoke acute spasm of the retinal artery (Varley et al., 1968). Such injuries may have an acute manifestation or a long-term result, as when the inferior rectus muscle is damaged with subsequent fibrosis and shortening. Silastic has been shown to be a satisfactory implant material in many trials and this has been confirmed in this series. As o. 5 mm-I mm thick triangles, it is TABLE IV Diagnostic accuracy of orbital floor defects
7o -I 6o Malar Fracture
With Malar Fractures 77"8% Pure Blow-outs 60.9 %
5° Number of Cases
6o
40
3o
20
Orbital Floors Explored 36 Proven Defects 28
Suspected Blowouts 23 Proven Blowouts I4
io Lilywhites 8
Lilywhites 9
firm enough to support the orbital contents, does not adhere to surrounding structures and provokes no adverse tissue reactions in this site. It is inert, which eliminates the necessity to overbuild the implant. The routine use of an eyebrow incision for the reduction of malar fractures is recommended since it affords visual confirmation of the stability of the reduction. This is not so with the Gillies' temporal approach, following which Knight and North (1961) reported a 4° per cent incidence of unacceptable instability. I f the reduction is unstable, direct wiring of the zygomatico-frontal suture can easily be performed and this will stabilise all but the more comminuted fractures.
T R A U M A T I C DEFECTS OF THE O R B I T A L F L O O R
I4I
An infra-orbital approach to the orbital floor is preferred to the lower eyelid incision (Hopkins, 1971) as the latter can jeopardise the lower tarsal plate, should post-operative infection occur. Persistent lymphoedema o f the lower eyelid is not encountered if the incision is kept to a minimum. T h e diagnostic accuracy calculations show that over-treatment has taken place. However, no complications occurred. T h e incidence of persistent diplopia is significantly less than that reported b y Barclay (1963) and the need for difficult ophthalmic procedures to restore muscle balance has been eliminated. TABLE V Post-operative complications o f Silastic implants Total number of implants
39
Symptom
Post-Operative
Diplopia
I week I month 6 months . I2months
Infra-orbital Paraesthesia
I 2 (2 3 p r e - o p . )
5 I (total loss of orbital floor)
.
I week I month 6 months . 12 months .
17 (15 pre-op.) 13 2 2
Periorbital Oedema
I week I month 6 months .
14 (33 pre-op.) i
Lymphoedema of Lower Eyelid
I week i month 3 months .
Enophthalmos
12 months .
Maxillary Sinusitis
I2 months .
8 8 I (total loss of orbital floor)
2 (radiographic evidence--no symptoms) I Implant removed ten months post-operatively as it was being extruded.
Longest time implant in situ Shortest time implant in situ . Mean
29 months I4 months 2I months
.
SUMMARY A high incidence o f traumatic orbital floor defects in 238 consecutive cases o f facial injury is reported and studied. T h e possible consequences o f such defects are discussed, aids to their diagnosis are outlined and the case for early surgical exploration is put forward. T h e technique is described in detail and the results o f treatment, especially the insertion o f a Silastic implant, are analysed.
14 2
BRITISH JOURNAL OF ORAL SURGERY
ACKNOWLEDGEMENTS My thanks are due to Mr T. C. Crewe for access to case notes and his encouragement. I am also grateful to Miss S. J. Easton for the illustrations and to those colleagues who helped in the preparation of this paper. REFERENCES BARCLAY,T. L. (I963). British Journal of Plastic Surgery, *6, 214. BRANDRICK, J. T. & T•RNBULL, T. (I972). In preparation. CONVERSE, J. M. & SMITH, B. (I95o). Archives of Ophthalmology of New York, 44, I. CRAMER, L. M,, TOOZE, F. M. & LERMAN, S. (r965). British Journal of Plastic Surgery, I8, I7I. FREEMAN, B. S. (r962). Plastic and Reconstructive Surgery, 29, 587. GILLIES, H. D., KroNER, T. P. & STONE, D. (I927). British Journal of Surgery, *4, 65 r. HOPKINS, R. (I97I). Annals of the Royal College of Surgeons, 49, 4o3 • KNIGHT, J. S. & NORTH, J. F. (I96r). British Journal of Plastic Surgery, x3, 325. LANG, W. (I889). Transactions of the Ophthalmological Society of the United Kingdom, 9, 43. PFEIFFER, R. L. (I943). Archives of Ophthalmologica, 3o, 718. VARLEY, E. W . B., HOLT-WILUAMS, A. D. & WATSON, P. G. (I968). British Journal of Oral Surgery, 6, 3I.
T R A U M A T I C D E F E C T S OF T H E ORBITAL FLOOR A. S. DAVIES,B.D.S., H.D.D, F.D.S.
Plymouth General Hospital
TRAUMATICorbital floor defects have been recognised since Lang (1889) reported a case of 'traumatic enophthalmos', which had been caused by a blow to the globe. Pfeiffer (1943) and Converse and Smith (I95O), described indirect fractures of the orbital floor, the latter introducing the term 'blow-out' to indicate those fractures of the floor in which the orbital rim remained intact. Such injuries are not uncommon. Cramer et al. (1965) found 64 (53"7 per cent) orbital floor defects in 119 fractures of the middle third of the face and Freeman (1962) reported that 26 (33 "7 per cent) of 77 cases with fractures of the zygomatico-maxillary complex had significant defects in the orbital floor. Several authors have outlined the diagnosis and management of these injuries, and mainly those writing in the American literature have emphasised the necessity for early operative intervention to prevent enophthalmos and persistent diplopia (Converse & Smith, 195o; Freeman, 1962; Cramer et al., 1965). Those surgeons dealing with maxillo-facial injuries are familiar with orbital anatomy, but it is pertinent to repeat that the floor is extremely thin, being thinnest medial to the infra-orbital groove and canal. As every fracture of the zygomaticomaxillary complex involves the orbital floor, the latter is frequently comminuted and leaves a defect. Such defects, if untreated, may result in enophthalmos and persistent diplopia due to atrophy of herniated orbital fat and interference with extraocular muscles. This paper describes a study in which the incidence of orbital floor defects in patients who had sustained facial injuries was assessed. It emphasises certain points in the diagnosis of these defects and outlines the active management. A standard operative approach is described, and a review is reported of cases in which Silastic sheeting was used to reconstitute the floor.
M A T E R I A L S AND M E T H O D S At Plymouth General Hospital 238 consecutive cases of facial trauma (includ~ ing soft tissue without bony injury) were studied over a period of I4 months. T h e study was, in part, retrospective and not all cases were treated personally. The presence of orbital floor defects is determined on the basis of history, clinical examination, radiography and operative findings. Of particular value in the clinical examination, is the presence of limited excursion of the globe with associated diplopia on upward and outward gaze (Fig. I). This suggests tethering of the inferior rectus muscle and makes operative exploration obligatory. Although, in theory, enophthalmos should be present due to the herniation of the orbital fat into the maxillary sinus, this may be obscured by the coincident periorbital oedema and ecchymosis. Standard I5 ° and 300 occipitomental views will demonstrate the clinically 133
134
BRITISH JOURNAL OF ORAL SURGERY
FIG. I Limited excursion of right globe on upward and outward gaze.
FIG. 2
FIG. 3
Fig. 2 . - - ' H a n g i n g drop' appearance of herniated orbital contents in left maxillary sinus. Fig. 3---View to demonstrate displacement at the zygomatico-frontal suture.
FIG. 4
FIG. 5
Fig. 4.--Blow-out fracture demonstrated on coronal plane tomography. Fig. 5.--Blow-out fracture demonstrated on sagittal plane tomography.
T R A U M A T I C DEFECTS OF THE O R B I T A L F L O O R
135
displaced fracture of the zygomatico-maxillary complex and a 'blow-out' shows cither as an opacity of the maxillary sinus or occasionally as the pathognomonic 'hanging drop' sign, produced by the herniating orbital contents (Fig. 2). However, the displacement of the complex at the zygomatico-frontal suture is the key to the management of the fractured malar and this may bc difficult to see on standard views. The Radiography Department in Plymouth General Hospital has evolved a view which shows the suture more clearly (Fig. 3) (Brandrick & TurnbuU, 1972). In those patients in whom the presence of an orbital floor defect is suspected, coronal orbital tomography is performed. Difficulties may be experienced in interpreting these films, especially if deviation from a true coronal plane has rcsultcd in apparent asymmetry of the orbital floors. However, thc defect can be clearly demonstrated (Fig. 4), and, certainly, coronal tomography is more helpful than sagittal plane tomography which is even more difficult to interpret (Fig. 5).
FIG. 6 FIG. 7 Fig. 6.--Reduction of zygomatico-frontal suture fracturevia eyebrow incision. Fig. 7.--Traction or forced duction test. • Surgical exploration is undertaken in patients in whom an orbital floor defect is suspected. In all malar fractures requiring elevation, the complex is approached through an eyebrow incision as opposed to the Gillies temporal approach (Gillies et al., I927). This exposure allows reduction of displacement at the zygomaticofrontal suture under direct vision (Fig. 6), and wiring can be undertaken in unstable fractures without further skin incision. An infra-orbital incision is made in cases with comminuted or unstable inferior orbital margins which are then wired, and also in cases where an orbital floor defect is suspected. When there is no apparent reason to make this incision, the traction or forced duction test is performed by grasping the insertion of the inferior rectus muscle through the conjunctiva of the lower fornix with fine toothed forceps (Fig. 7). Any restriction in upward movement, which can be compared with the normal side, suggests muscle tethering and indicates exploration. The skin is incised in a natural crease line, and the dissection carried down to the inferior orbital margin by splitting the orbicularis oculi fibres. The periosteum is incised just below the margin and elevated to expose the orbital floor. A broad blunt retractor supports the orbital contents while orbital tissues, which
136
BRITISH JOURNAL OF ORAL SURGERY
have passed through the floor defect, are gently teased upwards. Particular care is taken to ensure that the inferior rectus and inferior oblique muscles are freed from the edges of the defect. Any loose bony fragments are removed, and the defect is covered by a 0. 5 mm-I mm thick sheet of Silastic (cut to a triangular shape to avoid pressure on adjacent structures) which should be supported by sound orbital floor remains (Figs. 8A, 8B). The traction test is repeated to confirm that any muscle tethering has been released, and the pcriostcum is then carefully sutured to avoid extrusion of the implant. The wound is closed in layers.
FIG. 8 A, Insertion of Silastic orbital floor implant. B, Position of Silastic orbital floor implant.
In this series 5o Silastic implants were placed over orbital floor defects, 39 of them by the author. RESULTS It can be seen from Table I that of the 238 cases studied, 25.2 per cent were malar fractures, 5"9 per cent were 'blow-outs' and 5"4 per cent were Le Fort II and III fractures. The remaining 64. 5 per cent included soft tissue lacerations, mandibular and nasal fractures. 2I. I per cent of the total had orbital floor defects occurring as shown. Of the malar fractures, 46"6 per cent showed significant defects which also occurred in 6I. 5 per cent of the admittedly small number of Le Fort II and III fractures (Table II). Since pure 'blow-out' fractures classically occur after a single blow to the globe, the injuries in 89 patients presenting with a unilateral black eye, were evaluated (Table III). Of these, 28 (31"5 per cent) had an orbital floor defect
TRAUMATIC
DEFECTS
OF T H E
ORBITAL
FLOOR
I37
associated with a malar fracture, while 14 (I5"7 per cent) were pure 'blow-outs'. Orbital floor defects therefore occurred in 47..2 per cent of black eyes. A calculation of the accuracy of pre-operative diagnosis showed that this was 77"8 per cent in defects associated with malar fractures and 60"9 per cent in pure 'blow-outs' (Table IV). TABLE I Incidence of middle third fractures and orbital floor defects in 238 cases of facial trauma (25. I2. I969-11.3. I97 I)
30
-
Malar Fracture 25-2 % Total
Total Number of Defects
20 -
2I'I
IO
-
Malar Fracture + Defect Ii'8 Le Fort II &llI 5.4
Le Fort II & III + Defect 3"4
Pure Blow-out 5,9
The post-operative evaluation of the 39 personal Silastic implants are shown in Table V. The longest period for which an implant had been in place was 29 months, the shortest 14 months, with a mean of 2I months. One implant was removed as it presented subcutaneously IO months after insertion. Since there was no evidence of an inflammatory reaction, it is probable that the periosteal closure had been inadequate. One patient had persistent diplopia and enophthalmos six months after multiple intra-osseous wiring of a severely comminuted fracture of the zygomatico-maxiUary complex and the insertion of a large Silastic
138
BRITISH
JOURNAL
OF O R A L S U R G E R Y
implant. Augmentation of the floor support was considered, but on ophthalmic examination, no diplopia was found after one year. No persistent diplopia occurred in the untreated cases, though enophthalmos was found seven days after injury, in one patient who refused treatment for a 'blow-out'. TABLE I I Incidence of orbital floor defects in malar and Le Fort fractures 7°
-
60 Malar Fracture 60 5°
Number of Cases
-
% Incidence in Malar Fractures = 46-6 % Incidence in Le Fort Fractures = 61"5
40
3o Malar Fracture + Defect 28
20
IO
Le Fort II & III 13
-
Le Fort II & III + Defects 8
DISCUSSION Probably the paramount aim in the treatment of fractures involving the orbit is the prevention of persistent diplopia. Diplopia is frequently encountered in those patients who have a significant defect in the orbital floor and especially in those in whom the inferior oblique or inferior rectus muscle has become tethered to the bony fragments. T h e incidence of such defects is high, and in this series higher than previously reported. T h e presence of a small defect does not necessarily result in diplopia as
TRAUMATIC DEFECTS OF THE ORBITAL FLOOR
I39
evidenced by the lack of this symptom in the cases not surgically explored. However, where a defect of sufficient size is suspected on clinical and radiographic grounds, exploration of the orbital floor is justifiable. Primary exploration is a simple quick procedure, especially if the orbital rim is being wired. Operative exploration is further supported by the fact that in many cases bony spicules from TABLE III % Incidence of orbital floor defects in 89 unilateral black eyes
7 °
60
% Total
-
-
Malar Fracture 67-4
5o -
40
-
30
-
20
--
IO
-
Total Defect 47"2 Malar Fracture + Defect 3r'5
Pure Blow-out I5"7
Soft Tissue Injury I6"85
the thin orbital floor were found lying in a vertical position. This was most frequently seen in those cases in which there had been wide separation of the zygomatico-frontal suture and medial displacement of the malar complex, i.e., a Class V fracture (Knight & North, I96I). Compression of the orbital floor will rotate the fragments into the vertical position in which they probably remain even after reduction of the fracture. They may cause injury to any of the orbital K
BRITISH JOURNAL OF ORAL SURGERY
140
contents or may provoke acute spasm of the retinal artery (Varley et al., 1968). Such injuries may have an acute manifestation or a long-term result, as when the inferior rectus muscle is damaged with subsequent fibrosis and shortening. Silastic has been shown to be a satisfactory implant material in many trials and this has been confirmed in this series. As o. 5 mm-I mm thick triangles, it is TABLE IV Diagnostic accuracy of orbital floor defects
7o -I 6o Malar Fracture
With Malar Fractures 77"8% Pure Blow-outs 60.9 %
5° Number of Cases
6o
40
3o
20
Orbital Floors Explored 36 Proven Defects 28
Suspected Blowouts 23 Proven Blowouts I4
io Lilywhites 8
Lilywhites 9
firm enough to support the orbital contents, does not adhere to surrounding structures and provokes no adverse tissue reactions in this site. It is inert, which eliminates the necessity to overbuild the implant. The routine use of an eyebrow incision for the reduction of malar fractures is recommended since it affords visual confirmation of the stability of the reduction. This is not so with the Gillies' temporal approach, following which Knight and North (1961) reported a 4° per cent incidence of unacceptable instability. I f the reduction is unstable, direct wiring of the zygomatico-frontal suture can easily be performed and this will stabilise all but the more comminuted fractures.
T R A U M A T I C DEFECTS OF THE O R B I T A L F L O O R
I4I
An infra-orbital approach to the orbital floor is preferred to the lower eyelid incision (Hopkins, 1971) as the latter can jeopardise the lower tarsal plate, should post-operative infection occur. Persistent lymphoedema o f the lower eyelid is not encountered if the incision is kept to a minimum. T h e diagnostic accuracy calculations show that over-treatment has taken place. However, no complications occurred. T h e incidence of persistent diplopia is significantly less than that reported b y Barclay (1963) and the need for difficult ophthalmic procedures to restore muscle balance has been eliminated. TABLE V Post-operative complications o f Silastic implants Total number of implants
39
Symptom
Post-Operative
Diplopia
I week I month 6 months . I2months
Infra-orbital Paraesthesia
I 2 (2 3 p r e - o p . )
5 I (total loss of orbital floor)
.
I week I month 6 months . 12 months .
17 (15 pre-op.) 13 2 2
Periorbital Oedema
I week I month 6 months .
14 (33 pre-op.) i
Lymphoedema of Lower Eyelid
I week i month 3 months .
Enophthalmos
12 months .
Maxillary Sinusitis
I2 months .
8 8 I (total loss of orbital floor)
2 (radiographic evidence--no symptoms) I Implant removed ten months post-operatively as it was being extruded.
Longest time implant in situ Shortest time implant in situ . Mean
29 months I4 months 2I months
.
SUMMARY A high incidence o f traumatic orbital floor defects in 238 consecutive cases o f facial injury is reported and studied. T h e possible consequences o f such defects are discussed, aids to their diagnosis are outlined and the case for early surgical exploration is put forward. T h e technique is described in detail and the results o f treatment, especially the insertion o f a Silastic implant, are analysed.
14 2
BRITISH JOURNAL OF ORAL SURGERY
ACKNOWLEDGEMENTS My thanks are due to Mr T. C. Crewe for access to case notes and his encouragement. I am also grateful to Miss S. J. Easton for the illustrations and to those colleagues who helped in the preparation of this paper. REFERENCES BARCLAY,T. L. (I963). British Journal of Plastic Surgery, *6, 214. BRANDRICK, J. T. & T•RNBULL, T. (I972). In preparation. CONVERSE, J. M. & SMITH, B. (I95o). Archives of Ophthalmology of New York, 44, I. CRAMER, L. M,, TOOZE, F. M. & LERMAN, S. (r965). British Journal of Plastic Surgery, I8, I7I. FREEMAN, B. S. (r962). Plastic and Reconstructive Surgery, 29, 587. GILLIES, H. D., KroNER, T. P. & STONE, D. (I927). British Journal of Surgery, *4, 65 r. HOPKINS, R. (I97I). Annals of the Royal College of Surgeons, 49, 4o3 • KNIGHT, J. S. & NORTH, J. F. (I96r). British Journal of Plastic Surgery, x3, 325. LANG, W. (I889). Transactions of the Ophthalmological Society of the United Kingdom, 9, 43. PFEIFFER, R. L. (I943). Archives of Ophthalmologica, 3o, 718. VARLEY, E. W . B., HOLT-WILUAMS, A. D. & WATSON, P. G. (I968). British Journal of Oral Surgery, 6, 3I.