Protrusion of the Infraorbital Nerve into the Maxillary Sinus on CT: Prevalence, Proposed Grading Method, and Suggested Clinical Implications.
Lantos J E,Pearlman A N,Gupta A,Chazen J L,Zimmerman R D,Shatzkes D R,Phillips C D
AJNR. American journal of neuroradiology
BACKGROUND AND PURPOSE:The infraorbital nerve arises from the maxillary branch of the trigeminal nerve and normally traverses the orbital floor in the infraorbital canal. Sometimes, however, the infraorbital canal protrudes into the maxillary sinus separate from the orbital floor. We systematically studied the prevalence of this variant. MATERIALS AND METHODS:We performed a retrospective review of 500 consecutive sinus CTs performed at our outpatient centers. The infraorbital nerve protruded into the maxillary sinus if the entire wall of the infraorbital canal was separate from the walls of the sinus. We recorded the length of the bony septum that attached the infraorbital canal to the wall of the maxillary sinus and noted whether the protrusion was bilateral. We also measured the distance from the inferior orbital rim where the infraorbital canal begins to protrude into the sinus. RESULTS:There was a prevalence of 10.8% for infraorbital canal protrusion into the maxillary sinus and 5.6% for bilateral protrusion. The median length of the bony septum attaching the infraorbital canal to a maxillary sinus wall, which was invariably present, was 4 mm. The median distance at which the infraorbital nerve began to protrude into the sinus was 11 mm posterior to the inferior orbital rim. CONCLUSIONS:Although this condition has been reported in only 3 patients previously, infraorbital canal protrusion into the maxillary sinus was present in >10% of our cohort. Identification of this variant on CT could help a surgeon avoid patient injury.
10.3174/ajnr.A4588
Effects of infraorbital nerve's anatomical course on the fracture pattern of the orbital floor.
Kim Junhyung,Park Sang Woo,Choi Jaehoon,Jeong Woonhyeok,Kim Ryeolwoo
Journal of plastic, reconstructive & aesthetic surgery : JPRAS
In this study, details of the infraorbital nerve's (ION's) anatomical course variants were compared using computed tomography (CT), and relationships between the variants and fracture patterns in the orbital floor were investigated. Fifty-two normal individuals and 50 patients with unilateral isolated orbital floor fractures were enrolled in this study. Four measurements in normal individuals and five measurements in fracture patients were obtained in parasagittal sections. The anatomical variations of the ION were categorized into three types according to the classification by Ferences et al. Among the normal individuals, 42 orbits were classified as type 1 ION, 48 orbits as type 2, and 14 orbits as type 3. The distance from the inferior orbital rim to the upper border of the inferior orbital foramen and the length of descension portion of the ION in type 1 ION were significantly shorter than in type 2 and type 3 IONs. In patients with orbital floor fractures, the distance from the inferior orbital rim to the upper border of the inferior orbital foramen was positively correlated with herniation level of bone and soft tissue. The ION had three anatomical variants according to the degree of descension in the anterior portion of the orbit. When fracture of the orbital floor occurs in patients with type 1 ION, inferior displacement of the fractured orbital bone and orbital soft tissue may be less severe than in patients with other ION types.
10.1016/j.bjps.2017.10.006
Biomechanic Factors Associated With Orbital Floor Fractures.
Patel Sagar,Andrecovich Christopher,Silverman Michael,Zhang Liying,Shkoukani Mahdii
JAMA facial plastic surgery
IMPORTANCE:Orbital floor fractures are commonly seen in clinical practice, yet the etiology underlying the mechanism of fracture is not well understood. Current research focuses on the buckling theory and hydraulic theory, which implicate trauma to the orbital rim and the globe, respectively. OBJECTIVE:To elucidate and define the biomechanical factors involved in an orbital floor fracture. DESIGN, SETTING, AND PARTICIPANTS:A total of 10 orbits from 5 heads (3 male and 2 female) were used for this study. These came from fresh, unfixed human postmortem cadavers that were each selected so that the cause of death did not interfere with the integrity of orbital walls. Using a drop tower with an accelerometer, we measured impact force on the globe and rim of cadaver heads affixed with strain gauges. RESULTS:The mean impacts for rim and globe trauma were 3.9 J (95% CI, 3.4-4.3 J) and 3.9 J (95% CI, 3.5-4.3 J), respectively. Despite similar impact forces to the globe and rim, strain-gauge data displayed greater mean strain for globe impact (6563 μS) compared with rim impact (3530 μS); however, these data were not statistically significant (95% CI, 3598-8953 μS; P = .94). CONCLUSIONS AND RELEVANCE:Our results suggest that trauma directly to the globe predisposes a patient to a more posterior fracture while trauma to the rim demonstrates an anterior predilection. Both the hydraulic and buckling mechanisms of fracture exist and demonstrate similar fracture thresholds. LEVEL OF EVIDENCE:NA.
10.1001/jamafacial.2016.2153
Navigation-guided reduction and orbital floor reconstruction in the treatment of zygomatic-orbital-maxillary complex fractures.
Yu Hongbo,Shen Guofang,Wang Xudong,Zhang Shilei
Journal of oral and maxillofacial surgery : official journal of the American Association of Oral and Maxillofacial Surgeons
PURPOSE:To evaluate the effectiveness of image-guided navigation on open reduction and orbital floor reconstruction as treatment for zygomatic-orbital-maxillary complex fractures. PATIENTS AND METHODS:Six patients with zygomatic-orbital-maxillary complex fractures were enrolled in the present study. With preoperative planning and 3-dimensional simulation, the normal anatomic structures of the deformed area were recreated by superimposing and comparing the unaffected side with the affected side. The position of dislocated bone for reduction was defined, and surgical simulation was performed. All patients underwent open reduction and orbital floor reconstruction under the guidance of the navigation system. RESULTS:A fairly accurate match between the intraoperative anatomy and the computed tomography images was achieved through registration, with a systematic error of 1-mm difference. With guidance of the navigation system, open reduction of zygomatic-orbital-maxillary complex fractures and orbital floor reconstruction were performed in all cases. The reduction was checked by postoperative computed tomography scans, with a good match with preoperative planning noted. The maximal deviation between the reduction and preoperative planning was less than 2 mm. The symptoms associated with the orbital floor defects were eliminated, and the postoperative facial appearance of the patients was clearly improved. CONCLUSION:Navigation-guided open reduction of zygomatic-orbital-maxillary complex fractures with orbital floor reconstruction can be regarded as a valuable treatment option for this potentially complicated procedure.
10.1016/j.joms.2009.07.058
An anatomical study of the orbital floor in relation to the infraorbital groove: implications of predisposition to orbital floor fracture site.
Takahashi Yasuhiro,Nakano Takashi,Miyazaki Hidetaka,Kakizaki Hirohiko
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie
PURPOSE:To examine the anatomy of the orbital floor in relation to the infraorbital groove. METHODS:Twenty-two Japanese cadavers aged 86.9 ± 6.0 years at death were used. We examined whether the bony overhang on the infraorbital nerve extending laterally was connected to the segment medial to the infraorbital groove. The bone thicknesses at 1, 2, and 3 mm anterior to the junction between the infraorbital groove and the inferior orbital fissure were measured along the groove. We examined the angle between the infraorbital groove and the orbital floor, both at the medial and lateral margins, at the thinnest point in the above three measurement points. We used the measurement values examined in the left orbits to prevent doubling the number of the orbits. RESULTS:The bony overhang was not connected to the medial segment in 19 (86.4 %) orbits. The thickness at the thinnest point was thinner in the medial portion (1.02 ± 1.20 mm) than in the lateral portion (2.60 ± 1.82 mm; p = 0.001). The angle between the medial margin and the orbital floor was obtuse (156.5° ± 12.3°), compared with that of the lateral margin (104.0° ± 17.0°; p < 0.001). CONCLUSIONS:The results of this study imply that the medial portion has an anatomical weakness and few supportive structures. Although these findings were obtained only from Japanese cadavers, there may be associated with frequent occurrences of an orbital floor fracture just medial to the infraorbital groove.
10.1007/s00417-016-3455-2
An analysis of 733 surgically treated blowout fractures.
Chi Mi Jung,Ku Myun,Shin Kwang Hun,Baek Sehyun
Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde
PURPOSE:To evaluate current patient demographics and surgical outcomes from a large series of 733 surgically treated orbital fractures from an ophthalmologist's perspective. METHODS:We reviewed the medical records of 733 patients with orbital fracture, who were treated surgically by one of the authors at Gil Hospital, Gachon University, from May 2000 until September 2007. Data regarding patient demographics, signs and symptoms at presentation, cause of injury, nature of fracture, associated ocular and nonocular injury, surgical outcome and complications were collected. RESULTS:Male patients outnumbered female patients, and blowout fracture occurred most frequently between the ages of 20 and 29 years (mean age 30.7 years). Violent assault was the leading cause of the fractures, followed by fall/slip and traffic accidents. Common signs and symptoms were periorbital ecchymosis, ocular motility restriction, diplopia and enophthalmos. In the pediatric group, diplopia and ocular motility restriction were the most common. Subconjunctival hemorrhage, hyphema and commotio retinae were the most commonly associated ocular injuries. As for the location of fractures, medial wall fractures were the most common, followed by fractures of the inferior wall, and both medial and inferior walls, in order. The most common type of fracture was the 'comminuted' one. In the pediatric group, the percentage of trapdoor-type fracture was higher than in the adult group. Forty-four percent of the patients had diplopia preoperatively and 8.7% postoperatively. The average measurement of difference in the enophthalmos (> or = 2 mm) patient population was improved from 2.62 (+/-SD 0.9) to 1.73 (+/-SD 1.3) after surgery. Ocular motility restriction was preoperatively noted in 297 patients (40.5%), and only 18 patients (2.5%) showed restriction after surgery. CONCLUSION:Young male individuals are at the highest risk for orbital fractures. There are marked differences in the clinical symptomatology and findings between pediatric and adult orbital fractures. Diplopia, enophthalmos and ocular motility restriction improved by repair of fracture.
10.1159/000238932
Clinical signs of orbital wall fractures as a function of anatomic location.
Jank Siegfried,Schuchter Barbara,Emshoff Rüdiger,Strobl Heinrich,Koehler Julius,Nicasi Alessandro,Norer Burghard,Baldissera Ivo
Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics
OBJECTIVE:The objective of this study was to see whether clinical signs of medial orbital wall fractures distinguished these fractures from fractures of the lateral orbital wall and the orbital floor. STUDY DESIGN:The orbital fractures of 424 patients were analyzed. The patients were divided into 2 groups: (1) patients with orbital fractures with a medial orbital wall component and (2) patients with orbital fractures without a medial orbital wall component. RESULTS:Orbital fractures with involvement of the medial orbital wall showed a significantly higher incidence (P =.001) of diplopia and exophthalmos (P =.039) than fractures without involvement of the medial wall. CONCLUSION:Posttraumatic orbital clinical signs are associated with a higher incidence of medial orbital wall component fracture. Apparent lack of involvement of the medial orbital wall should not be an exclusion criterion for a surgical intervention when clinical orbital signs exist.
10.1016/S1079210403003172
Orbital blowout fractures and race.
de Silva Don Julian,Rose Geoffrey E
Ophthalmology
PURPOSE:To examine the type of orbital blowout fracture and its variation with race. DESIGN:Retrospective review of computed tomography (CT) scans and demography in an unselected cohort of patients with orbital blowout fractures. PARTICIPANTS:Patients with a high-resolution CT scan of adequate quality for analysis who presented with an orbital blowout fracture to the Orbital Clinic at Moorfields Eye Hospital. Patients with fractures involving the orbital rim or the cranium, or with penetrating injuries of the globe or orbit, were omitted from the study. METHODS:Demographic and ethnic information was collected for each patient, and the orbital scans were reviewed by a single observer. On the basis of coronal and axial imaging, a fracture was classified as affecting up to 4 areas: the floor lateral to the infraorbital canal (area 1, "A1"), the floor medial to the canal ("A2"), the maxillo-ethmoidal strut ("inferomedial" strut, "A3"), and the medial wall blowout fracture ("A4"); with fractures involving the inferomedial strut, it was noted whether there was displacement or rotation of the strut. Ethnic origin was classified as Caucasian, Afro-Caribbean, or Asian (Oriental or Indian). MAIN OUTCOME MEASURES:The proportion of different walls involved in orbital blowout fractures within 3 ethnic groups. RESULTS:A total of 152 patients (125 men, 82%) had imaging adequate for analysis; 103 (68%) were Caucasian, 19 (12%) were Afro-Caribbean, and 30 (20%) were Asian. Caucasians most commonly had floor fractures (A1 or A2 in 56 orbits, 54%) compared with 10 of 103 purely medial fractures (A4, 10%); in contrast, medial fractures were the most common type in Afro-Caribbean patients (7/19 cases, 37%), and purely floor fractures occurred in only 2 cases (10%) (P<0.005). Asian patients had results similar to those for Caucasian patients, with isolated floor fractures being the most common (14/30 cases, 47%). CONCLUSIONS:Most blowout fractures involve the orbital floor in Caucasian and Asians, whereas in Afro-Caribbeans the most common site for fracture is the medial wall. FINANCIAL DISCLOSURE(S):The author(s) have no proprietary or commercial interest in any materials discussed in this article.
10.1016/j.ophtha.2011.05.001
The Incidence and Risk Factors of Medial and Inferior Orbital Wall Fractures in Korea: A Nationwide Cohort Study.
Journal of clinical medicine
PURPOSE:We aimed to investigate orbital wall fracture incidence and risk factors in the general Korean population. METHOD:The Korea National Health Insurance Service-National Sample Cohort dataset was analyzed to find subjects with an orbital wall fracture between 2011 and 2015 (based on the diagnosis code) and to identify incident cases involving a preceding disease-free period of 8 years. The incidence of orbital wall fracture in the general population was estimated, and the type of orbital wall fracture was categorized. Sociodemographic risk factors were also examined using Cox regression analysis. RESULTS:Among 1,080,309 cohort subjects, 2415 individuals with newly diagnosed orbital wall fractures were identified. The overall incidence of orbital wall fractures was estimated as 46.19 (95% CI: 44.37-48.06) per 100,000 person-years. The incidence was high at 10-29 and 80+ years old and showed a male predominance with an average male-to-female ratio of 3.33. The most common type was isolated inferior orbital wall fracture (59.4%), followed by isolated medial orbital wall fracture (23.7%), combination fracture (15.0%), and naso-orbito-ethmoid fracture (1.5%). Of the fracture patients, 648 subjects (26.8%) underwent orbital wall fracture repair surgeries. Male sex, rural residence, and low income were associated with an increased risk of orbital wall fractures. CONCLUSIONS:The incidence of orbital wall fractures in Korea varied according to age groups and was positively associated with male sex, rural residency, and low economic income. The most common fracture type was an isolated inferior orbital wall fracture.
10.3390/jcm11092306
Predicting late enophthalmos: Differences between medial and inferior orbital wall fractures.
Choi Jaehoon,Park Sang Woo,Kim Junhyung,Park Jeongseob,Kim Jun Sik
Journal of plastic, reconstructive & aesthetic surgery : JPRAS
INTRODUCTION:The purpose of this study was to compare the strength of the relationships between predictors and late-onset enophthalmos in medial and inferior orbital wall fractures and to determine the most significant predictive factor of enophthalmos in medial or inferior orbital wall fracture. METHODS:Sixty-three adult patients with unilateral medial or inferior orbital wall fracture who had been left untreated for more than two months were enrolled in this study. Patients who had accompanying multiple orbital wall fractures and those with orbital-zygomatic fractures were excluded. Orbital defect area and herniated muscle and fat volumes were evaluated using computed tomography. The degree of enophthalmos was measured using a Hertel exophthalmometer. RESULTS:Herniated muscle and fat volumes were positively correlated with defect area in the medial orbital wall fracture but showed no positive correlation with inferior orbital wall fracture. In the medial orbital wall fracture group, enophthalmos was positively correlated with defect area and herniated muscle and fat volumes. Defect area was more highly related to enophthalmos than other analyzed metrics. The defect area predictive of enophthalmos was 1.98 cm. However, enophthalmos was positively correlated only with herniated fat volume in inferior orbital wall fracture. The herniated fat volume predictive of enophthalmos was 343.50 mm. CONCLUSION:Orbital defect area in medial orbital wall fracture and herniated fat volume in inferior orbital wall fracture were the most significant predictors of late-onset enophthalmos.
10.1016/j.bjps.2016.08.004
Prevalence and severity of orbital blowout fractures.
Khojastepour L,Moannaei M,Eftekharian H R,Khaghaninejad M S,Mahjoori-Ghasrodashti M,Tavanafar S
The British journal of oral & maxillofacial surgery
We aimed to study the prevalence of orbital blowout fractures and evaluate the causes and the location of orbital cavity fractures. In this cross-sectional study, the medical records of all patients admitted with facial trauma were assessed, sociodemographic information as well as the aetiology of trauma extracted, and the computed tomographic images of the patients were reassessed. Location of orbital blowout fractures and the severity of orbital fractures were evaluated. A total of 203 cases had blowout fractures (175 male and 28 female patients with a mean (SD) age of 36 (16) years. Road traffic accidents (n=139, 69%) were the most common cause of orbital blowout fractures. Falls (n=29, 14%) and assault (n=20, 10%) were the other causes of trauma to the orbital structure, which resulted in blowout fractures. The medial wall was the most commonly involved location (n=81, 40%) followed by orbital floor (n=64, 32%), the combination of medial wall and floor (n=36, 18%), medial wall and maxilloethmoidal strut combination (n=13, 6%), and all the three locations altogether (n=9, 4%). Most of the blow-out fractures had mild severity (n=107, 53%). There was a significant relation between the severity and location of the blowout fractures (p<0.001).
10.1016/j.bjoms.2020.07.001
Orbital blowout fracture location in Japanese and Chinese patients.
Sun Michelle T,Wu Wencan,Watanabe Akihide,Kakizaki Hirohiko,Chen Ben,Ueda Kosuke,Katori Nobutada,Takahashi Yasuhiro,Selva Dinesh
Japanese journal of ophthalmology
PURPOSE:To characterize the location of orbital blowout fractures in Asian individuals. METHODS:This was a retrospective review of 470 consecutive Asian patients with orbital blowout fractures who presented to four tertiary care hospitals in Japan and China. Computed tomography (CT) characterized the location and severity of fractures involving the medial wall, the orbital floor, and/or the maxilloethmoidal strut. RESULTS:A total of 475 orbital blowout fractures were identified. More than one fracture location was involved in 19% of all cases. The medial orbital wall was the most commonly involved location, presenting in 29 cases (61%), of which 204 (43%) were isolated medial blowout fractures. The orbital floor was the second most common location involved, present in 226 cases (48%) with 150 isolated orbital floor fractures (32%), while the maxilloethmoidal strut was involved in 45 cases (9%) with 30 of those being isolated strut fractures (6%). The majority of fractures (62%) were classified as moderately severe, whilst 14% were mild, and 24% were severe. Associated nasal fractures were present in 16% of the cases. CONCLUSIONS:Orbital blowout fractures in Japanese and Chinese individuals occur most commonly in the medial wall. This is in contrast to previous reports on white individuals, who tend to sustain fractures involving the orbital floor rather than the medial wall.
10.1007/s10384-014-0357-x
Intimate partner violence: an underappreciated etiology of orbital floor fractures.
Clark Thomas J,Renner Lynette M,Sobel Rachel K,Carter Keith D,Nerad Jeffrey A,Allen Richard C,Shriver Erin M
Ophthalmic plastic and reconstructive surgery
PURPOSE:To evaluate the prevalence of intimate partner violence (IPV) in a large population of female orbital floor fracture patients and provide recommendations on effectively identifying and referring IPV survivors. METHODS:Retrospective review of facial fracture patients examined at the University of Iowa Hospitals and Clinics between January 1995 and April 2013. International Classification of Diseases, Ninth Revision, codes and medical record review were used to determine the prevalence of IPV victimization and clinical outcomes. RESULTS:A total of 1,354 women and 4,296 men sustained facial fractures. Of these, 405 women and 1,246 men sustained orbital floor fractures. Leading mechanisms of orbital floor fractures in women were motor vehicle collisions (29.9%) and falls (24.7%). Twenty percent had no etiology documented. Intimate partner violence-associated assault was the third leading documented cause of orbital floor fractures in women (7.6%) followed by non-IPV-associated assault (7.2%). Among women with orbital floor fractures due to assault, leading patterns of injury included the following: isolated orbital floor fractures (38.7%, 12/31 in IPV patients; 55.2%, 16/29 in non-IPV patients), zygomaticomaxillary complex fractures (35.5%, 11/31 in IPV patients; 17.2%, 5/29 in non-IPV patients), and orbital floor plus medial wall fractures (16.1%, 5/31 in IPV patients; 24.1%, 7/29 in non-IPV patients). Involvement of ancillary services was documented in 20.0% (7 law enforcement and 5 social service agencies, 12/60) of assault-related orbital floor fracture cases. Ascertainment of patient safety was documented in 1.7% (1/60) of these cases. CONCLUSIONS:Ophthalmologists treating orbital floor fracture patients should maintain a high index of suspicion for IPV and screen accordingly. Following IPV disclosure, patient safety should be assessed and referral provided.
10.1097/IOP.0000000000000165
Surgical anatomy and variations of the infraorbital nerve.
Ference Elisabeth H,Smith Stephanie S,Conley David,Chandra Rakesh K
The Laryngoscope
OBJECTIVES/HYPOTHESIS:To assess relevant variations in the anatomical course of the infraorbital nerve (ION). This understanding may reduce the risk of surgical injury. METHODS:A total of 100 consecutive computed-tomography sinus studies obtained in a tertiary referral center were reviewed, and measurements were made of the 200 IONs. Anatomic variants were classified into three types based on the degree to which (if any) the nerve's course descended from the maxillary roof into the sinus lumen. RESULTS:A total of 60.5% of IONs were entirely contained within the sinus roof. In 27.0%, the nerve canal descended below the roof but remained juxtaposed to it. In 12.5%, the ION descended into the sinus lumen. The proportion of IONs descending into the sinus significantly increased to 27.7% when an infraorbital ethmoid cell was present (chi-square P < 0.001) and to 50% when the nerve was contained within a lamella of such a cell (chi-square P < 0.001). Descended nerves terminated in a foramen located an average of 11.9 ± 2.5 mm below the infraorbital rim, significantly further below the orbit than nondescended nerves (t test P < 0.001). Descended nerves were located a mean distance of 8.6 ± 2.9 mm below the sinus roof and traversed the sinus lumen diagonally for a mean length of 15.4 ± 3.1 mm. CONCLUSIONS:Descent of the ION into the maxillary sinus is a common anatomic variant that is more prevalent in the setting of an ipsilateral infraorbital ethmoid cell. Descended nerves are associated with the foramen significantly further below the inferior orbital rim than those of nondescended nerves. These observations may help surgeons avoid iatrogenic ION injury. LEVEL OF EVIDENCE:N/A.
10.1002/lary.25089
Role of medial orbital wall morphologic properties in orbital blow-out fractures.
Song Won Kyung,Lew Helen,Yoon Jin Sook,Oh Min-Jin,Lee Sang Yeul
Investigative ophthalmology & visual science
PURPOSE:This study compares medial orbital wall supporting structures in patients with isolated inferior and medial wall fractures. METHODS:The morphologic properties in all consecutive patients with periocular trauma who underwent orbital computed tomography (CT) scans from January 2004 to March 2006 were reviewed. On CT scans, the size of the fracture, the number of ethmoid air cell septa, and the length and height of the lamina papyracea were measured. RESULTS:In 118 patients without orbital wall fracture, there were no bilateral differences in the measured structures. We took measurements from the opposite site in patients with fractures in whom it was difficult to visualize the structures at the fractured site. Seventy patients with medial wall fractures and 37 with inferior wall fractures showed no differences in sex, side of impact, etiology of the trauma, association with intraocular injuries, fracture size, anterior and posterior height, anteroposterior length, or the area of the lamina papyracea. In contrast, the number of ethmoid air cell septa was significantly lower (3.09+/-0.86 vs. 3.62+/-0.79, P=0.002) and the lamina papyracea area supported per ethmoid air cell septum was significantly higher (137.55+/-40.11 mm(2) vs. 119.64+/-38.14 mm(2), P=0.028) in patients with medial wall fractures than in those with inferior wall fractures. CONCLUSIONS:Patients with fewer ethmoid air cell septa and a larger lamina papyracea area per septum are more likely to develop medial wall fractures than inferior wall fractures.
10.1167/iovs.08-2204
Role of inferior orbital wall morphologic properties in isolated orbital blow-out fracture.
Park Jong-Seo,Lew Helen,Lee Sang-Yeul
Ophthalmic research
PURPOSE:To compare inferior orbital wall morphology between isolated inferior and medial orbital wall fracture patients. METHODS:The morphologic properties of patients with isolated blow-out fractures involving the medial wall or inferior wall treated from August 2004 to August 2009 were reviewed. The cross-sectional area, thickness, gradient, and curvature of the inferior wall were measured via orbital CT in the opposite non-traumatized eye. RESULTS:Patients with isolated inferior wall fractures (n = 77) and isolated medial wall fractures (n = 78) evidenced no differences in sex, age, etiology of trauma, laterality of trauma, and associated concomitant intraocular injuries. The cross-sectional area, thickness, and gradient of the inferior wall did not differ significantly between the 2 groups. However, the coefficient of curvature was significantly greater in patients with inferior wall fracture than in patients with medial wall fracture (0.016 ± 0.006 vs. 0.006 ± 0.002, respectively; p = 0.000). CONCLUSION:Patients with more convex and steep inferior walls are more likely to incur isolated inferior wall fractures than isolated medial wall fractures.
10.1159/000326894
Buckling and hydraulic mechanisms in orbital blowout fractures: fact or fiction?
Ahmad Fateh,Kirkpatrick Niall A,Lyne Jonathan,Urdang Michael,Waterhouse Norman
The Journal of craniofacial surgery
Since the first description of orbital blowout fractures, there has been much confusion as to their etiology. Two principal mechanisms have been proposed to explain their production, the buckling and the hydraulic mechanisms caused, respectively, by trauma to the orbital rim and the globe of the eye. The aim of this study was to evaluate both mechanisms qualitatively and quantitatively. Our protocol used intact cadavers, quantifiable intraocular pressure, variable and quantifiable force, and quantifiable bone strain distribution with strain gauge analysis. One orbit of each cadaver was used to simulate each of the two mechanisms, allowing direct comparison. Fractures produced by the buckling mechanism were limited to the anterior part of the orbital floor, with strain readings reaching up to 3756 microepsilon. Posteriorly, strain did not exceed 221 microepsilon. In contrast, hydraulic-type fractures were much larger, involving anterior and posterior parts of the floor as well as the medial wall of the orbit. Here, strain exceeded 3756 microepsilon in both parts of the floor. Furthermore, we have demonstrated that the average energy required to fracture the orbital floor by the buckling mechanism is 1.54 J, whereas an average energy of 1.22 J is needed to produce this fracture by the hydraulic mechanism. Our results suggest that efforts to establish one or another mechanism as the primary etiology are misplaced. Both mechanisms produce orbital blowout fractures, with different and specific characteristics. We believe this provides the basis for our reclassification of such fractures.
Anatomy of the inferior orbital fissure: implications for endoscopic cranial base surgery.
De Battista Juan Carlos,Zimmer Lee A,Theodosopoulos Philip V,Froelich Sebastien C,Keller Jeffrey T
Journal of neurological surgery. Part B, Skull base
Considering many approaches to the skull base confront the inferior orbital fissure (IOF) or sphenomaxillary fissure, the authors examine this anatomy as an important endoscopic surgical landmark. In morphometric analyses of 50 adult human dry skulls from both sexes, we divided the length of the IOF into three segments (anterolateral, middle, posteromedial). Hemotoxylin- and eosin-stained sections were analyzed. Dissections were performed using transnasal endoscopy in four formalin-fixed cadaveric cranial specimens (eight sides); three endoscopic approaches to the IOF were performed. IOF length ranged from 25 to 35 mm (mean 29 mm). Length/width of the individual anterolateral, middle, and posteromedial segments averaged 6.46/5, 4.95/3.2, and 17.6/ 2.4 mm, respectively. Smooth muscle within the IOF had a consistent relationship with several important anatomical landmarks. The maxillary antrostomy, total ethmoidectomy approach allowed access to the posteromedial segment of the fissure. The endoscopic modified, medial maxillectomy approach allowed access to the middle and posterior-medial segment. The Caldwell-Luc approach allowed complete exposure of the IOF. The IOF serves as an important anatomic landmark during endonasal endoscopic approaches to the skull base and orbit. Each of the three segments provides a characteristic endoscopic corridor, unique to the orbit and different fossas surrounding the fissure.
10.1055/s-0032-1301398