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ARTICLE IN PRESS Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
Short communication
An anomalous case of an indirect orbital floor fracture Matteo Nicolotti ∗,1 , Giuseppe Poglio, Fabrizio Grivetto, Arnaldo Benech S.C.D.U. Chirurgia Maxillo-Facciale, A.O.U. Maggiore della Carità di Novara, Università degli studi del Piemonte Orientale “Amedeo Avogadro”, Reparto di Chirurgia Maxillo-Facciale, C.so Mazzini 18, 28100 Novara, NO, Italy Accepted 6 March 2014
Abstract Fractures of the orbital floor are common in facial trauma. Those that comprise only the orbital floor are called indirect fractures or pure internal orbital floor fractures. We present the case of an indirect fracture of the orbital floor after direct trauma to the back of the head caused by a bicycle accident. To the best of our knowledge this is the first time that this mechanism for such a fracture has been reported. © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Indirect orbital fracture; Blowout fracture
Introduction Fractures of the orbital floor alone are called indirect fractures of the orbital floor or pure internal fractures of the orbital floor. These differ from those that involve the orbital rim and are caused by direct trauma.1 Among all maxillofacial fractures, the incidence of orbital fractures is reported to be about 57% and the incidence of isolated fractures of the orbital floor about 21%.2 We present the case of an indirect fracture of the orbital floor diagnosed after a cycling accident and direct blow to the back of the head. Case report A 37-year-old white woman presented after a cycling accident. She had fallen and hit her right occipital area and had not lost consciousness. The cerebral computed tomography (CT) scan showed a linear fracture of the right side of the occipital bone and a small extradural haematoma (Fig. 1).
She reported vertical diplopia despite the absence of any sign of facial trauma, periorbital swelling, or haematoma. She had no abrasions of the eyelid or lacerations. There was only minimal left enophthalmos (Fig. 2). Later CT of the orbits showed a blow-out fracture of the left orbital floor with entrapment of the inferior rectus muscle. The orbital rim was intact. The orthoptic evaluation confirmed that the left globe was raised and Hertel exophthalmometry values (left eye 13 mm; right eye 17 mm) showed left enophthalmos (Fig. 3). After routine medical examination we repaired the fracture through a transconjunctival approach to the orbital floor, using resorbable bovine pericardium membrane (Tutopatch® ). The patient was discharged the day after operation and at repeated orthoptic examination one month later the left ocular globe was in its normal position and the Herthel exophthalmometry values were 16 mm on the left and 17 mm on the right.
Discussion ∗
Corresponding author. Tel.: +39 3393863951; fax: +39 03213733894. E-mail address: [email protected] (M. Nicolotti). 1 Resident Maxillofacial Surgeon.
The mechanism involved in indirect blowout has been investigated by several authors, and 2 theories have been postulated.
http://dx.doi.org/10.1016/j.bjoms.2014.03.004 0266-4356/© 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
YBJOM-4215; No. of Pages 3
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M. Nicolotti et al. / British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
Fig. 3. Coronal computed tomographic slice. Evidence of a blowout fracture of the orbital floor and entrapment of the inferior rectus muscle. Fig. 1. Axial computed tomographic slice. (A) Blowout fracture of the orbital floor. The rim is intact. (B) Composite fracture of the occipital bone.
Smith and Regan proposed the so called “hydraulic theory” by which the compression of the eyeball by an external force increases the hydraulic pressure and applies a force to the orbital floor which, if sufficient, results in a fracture.3 The “buckling theory”, described by Fujino, postulated that forces applied to the inferior orbital rim are transmitted posteriorly through the thin orbital floor and may result in a buckling of bone and so produce an indirect fracture of the orbital floor.4 Both these mechanisms have been supported by vari-
ous clinical and experimental studies conducted on dry skulls, cadavers, and animals. After a review of papers published on the subject, we found just one that analysed the direction of the striking force. Nagasao et al.5 studied the effect of the angle of strike on the buckling mechanism in blowout fractures, and stated that the theoretical width of the fracture was the greatest when the striking angle was 30◦ , followed by 15◦ and 0◦ . We found no papers that described the mode of injury seen in our case. We think that the forces applied by the trauma were transmitted to the orbital floor, and resulted in its fracture as in the “buckling mechanism” described.4 The difference is that the trauma was directed at the back of the head and not at the orbital rim. Not only the fracture is indirect, but also the trauma.
Ethics statement The patient has given her consent to the publication of personal data and photos necessary to complete this study.
Authors’ contributions
Fig. 2. Left profile showing no periorbital swelling or haematoma, but there is evidence of enophthalmos. The horizontal line A indicates the normal protrusion of the eyeball measured on the right eye; the horizontal line B indicates the difference between the normal protrusion and the enophthalmic eyeball (published with the permission of the patient).
Dr. Matteo Nicolotti and Dr. Giuseppe Poglio contributed to the conception and design of study, review and case series. Dr. Giuseppe Poglio and Dr. Fabrizio Grivetto performed the acquisition of data: laboratory or clinical/literature search. Prof. Arnaldo Benech and Dr. Matteo Nicolotti provided the final approval and were the guarantors of the manuscript.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
YBJOM-4215; No. of Pages 3
ARTICLE IN PRESS
M. Nicolotti et al. / British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
References 1. Gonzalez MO, Durairaj VD. Indirect orbital floor fractures: a metaanalysis. Middle East Afr J Ophthalmol 2010;17:138–41. 2. Scherer M, Sullivan WG, Smith Jr DJ, Phillips LG, Robson MC. An analysis of 1423 facial fractures in 788 patients at an urban trauma center. J Trauma 1989;29:388–90.
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3. Smith B, Regan Jr WF. Blowout fracture of the orbit; mechanism and correction of internal orbital fracture. Am J Ophthalmol 1957;44:733–9. 4. Fujino T. Experimental fracture of the orbit. Plast Reconstr Surg blowout 1974;(54):81–2. 5. Nagasao T, Miyamoto J, Nagasao M, et al. The effect of striking angle on the buckling mechanism in blowout fracture. Plast Reconstr Surg 2006;117:2373–80.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
ARTICLE IN PRESS Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
Short communication
An anomalous case of an indirect orbital floor fracture Matteo Nicolotti ∗,1 , Giuseppe Poglio, Fabrizio Grivetto, Arnaldo Benech S.C.D.U. Chirurgia Maxillo-Facciale, A.O.U. Maggiore della Carità di Novara, Università degli studi del Piemonte Orientale “Amedeo Avogadro”, Reparto di Chirurgia Maxillo-Facciale, C.so Mazzini 18, 28100 Novara, NO, Italy Accepted 6 March 2014
Abstract Fractures of the orbital floor are common in facial trauma. Those that comprise only the orbital floor are called indirect fractures or pure internal orbital floor fractures. We present the case of an indirect fracture of the orbital floor after direct trauma to the back of the head caused by a bicycle accident. To the best of our knowledge this is the first time that this mechanism for such a fracture has been reported. © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Indirect orbital fracture; Blowout fracture
Introduction Fractures of the orbital floor alone are called indirect fractures of the orbital floor or pure internal fractures of the orbital floor. These differ from those that involve the orbital rim and are caused by direct trauma.1 Among all maxillofacial fractures, the incidence of orbital fractures is reported to be about 57% and the incidence of isolated fractures of the orbital floor about 21%.2 We present the case of an indirect fracture of the orbital floor diagnosed after a cycling accident and direct blow to the back of the head. Case report A 37-year-old white woman presented after a cycling accident. She had fallen and hit her right occipital area and had not lost consciousness. The cerebral computed tomography (CT) scan showed a linear fracture of the right side of the occipital bone and a small extradural haematoma (Fig. 1).
She reported vertical diplopia despite the absence of any sign of facial trauma, periorbital swelling, or haematoma. She had no abrasions of the eyelid or lacerations. There was only minimal left enophthalmos (Fig. 2). Later CT of the orbits showed a blow-out fracture of the left orbital floor with entrapment of the inferior rectus muscle. The orbital rim was intact. The orthoptic evaluation confirmed that the left globe was raised and Hertel exophthalmometry values (left eye 13 mm; right eye 17 mm) showed left enophthalmos (Fig. 3). After routine medical examination we repaired the fracture through a transconjunctival approach to the orbital floor, using resorbable bovine pericardium membrane (Tutopatch® ). The patient was discharged the day after operation and at repeated orthoptic examination one month later the left ocular globe was in its normal position and the Herthel exophthalmometry values were 16 mm on the left and 17 mm on the right.
Discussion ∗
Corresponding author. Tel.: +39 3393863951; fax: +39 03213733894. E-mail address: [email protected] (M. Nicolotti). 1 Resident Maxillofacial Surgeon.
The mechanism involved in indirect blowout has been investigated by several authors, and 2 theories have been postulated.
http://dx.doi.org/10.1016/j.bjoms.2014.03.004 0266-4356/© 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
YBJOM-4215; No. of Pages 3
xxx.e2
ARTICLE IN PRESS
M. Nicolotti et al. / British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
Fig. 3. Coronal computed tomographic slice. Evidence of a blowout fracture of the orbital floor and entrapment of the inferior rectus muscle. Fig. 1. Axial computed tomographic slice. (A) Blowout fracture of the orbital floor. The rim is intact. (B) Composite fracture of the occipital bone.
Smith and Regan proposed the so called “hydraulic theory” by which the compression of the eyeball by an external force increases the hydraulic pressure and applies a force to the orbital floor which, if sufficient, results in a fracture.3 The “buckling theory”, described by Fujino, postulated that forces applied to the inferior orbital rim are transmitted posteriorly through the thin orbital floor and may result in a buckling of bone and so produce an indirect fracture of the orbital floor.4 Both these mechanisms have been supported by vari-
ous clinical and experimental studies conducted on dry skulls, cadavers, and animals. After a review of papers published on the subject, we found just one that analysed the direction of the striking force. Nagasao et al.5 studied the effect of the angle of strike on the buckling mechanism in blowout fractures, and stated that the theoretical width of the fracture was the greatest when the striking angle was 30◦ , followed by 15◦ and 0◦ . We found no papers that described the mode of injury seen in our case. We think that the forces applied by the trauma were transmitted to the orbital floor, and resulted in its fracture as in the “buckling mechanism” described.4 The difference is that the trauma was directed at the back of the head and not at the orbital rim. Not only the fracture is indirect, but also the trauma.
Ethics statement The patient has given her consent to the publication of personal data and photos necessary to complete this study.
Authors’ contributions
Fig. 2. Left profile showing no periorbital swelling or haematoma, but there is evidence of enophthalmos. The horizontal line A indicates the normal protrusion of the eyeball measured on the right eye; the horizontal line B indicates the difference between the normal protrusion and the enophthalmic eyeball (published with the permission of the patient).
Dr. Matteo Nicolotti and Dr. Giuseppe Poglio contributed to the conception and design of study, review and case series. Dr. Giuseppe Poglio and Dr. Fabrizio Grivetto performed the acquisition of data: laboratory or clinical/literature search. Prof. Arnaldo Benech and Dr. Matteo Nicolotti provided the final approval and were the guarantors of the manuscript.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
YBJOM-4215; No. of Pages 3
ARTICLE IN PRESS
M. Nicolotti et al. / British Journal of Oral and Maxillofacial Surgery xxx (2014) xxx.e1–xxx.e3
References 1. Gonzalez MO, Durairaj VD. Indirect orbital floor fractures: a metaanalysis. Middle East Afr J Ophthalmol 2010;17:138–41. 2. Scherer M, Sullivan WG, Smith Jr DJ, Phillips LG, Robson MC. An analysis of 1423 facial fractures in 788 patients at an urban trauma center. J Trauma 1989;29:388–90.
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3. Smith B, Regan Jr WF. Blowout fracture of the orbit; mechanism and correction of internal orbital fracture. Am J Ophthalmol 1957;44:733–9. 4. Fujino T. Experimental fracture of the orbit. Plast Reconstr Surg blowout 1974;(54):81–2. 5. Nagasao T, Miyamoto J, Nagasao M, et al. The effect of striking angle on the buckling mechanism in blowout fracture. Plast Reconstr Surg 2006;117:2373–80.
Please cite this article in press as: Nicolotti M, et al. An anomalous case of an indirect orbital floor fracture. Br J Oral Maxillofac Surg (2014), http://dx.doi.org/10.1016/j.bjoms.2014.03.004
