Characterization of Inferior Rectus Muscle Action in Normal Subjects Using Real-Time Magnetic Resonance Imaging of the Orbit.

Traumatic rupture of the inferior rectus muscle: clinical presentation and surgical management

Background, Aim, and Objectives: Orbital floor blow out fractures are uncommon in children but can present with a dilemma in the Emergency department upon presentation. We collected case reports of 17 cases over a three-year period. The patients were selected from the age group six to 13 years of age with history of trivial blunt orbital trauma. The main complaint was mild pain in the eye upon presentation. Five patients were having clinical presentation of oculo-cardiac reflex. The suspected patients underwent Cone Beam CT of the midface with multiplanar cone beam reconstruction which confirmed the diagnosis of orbital floor fractures with trap door defect or minimal displacement and in a few cases inferior rectus entrapment. Orbital floor trapdoor fractures have oblivious features upon presentation and can easily be overlooked if not evaluated managed by expert healthcare providers which can lead to significant morbidity and even mortality in patients with oculocardiac reflex. Cone Beam CT of mid face with multiplanar reconstruction is the standard of care in the diagnosis and management of white eyed blow out orbital floor fractures in the provision of evidenced based healthcare practice. Methodology: This is a retrospective cohort study to evaluate the results of pediatric age group with trapdoor and blow out orbital floor fractures who underwent CBCT for the diagnosis and further management. Seventeen cases were selected who were in the age group between 6 to 13 years.12 cases underwent surgery for orbital floor exploration and nine were having inferior rectus muscle entrapment which was released. Five patients were managed non surgically. Result: One patient disappeared in this group during one-year post-operative follow up. No residual defect was found in the remaining sixteen patients. Cone beam Computer tomography with multiplanar reconstruction should be the standard of care for the diagnosis and treatment of blow out and trapdoor orbital fractures. Strength and limitations: Although this study is of a limited number of pediatric patients, but it highlights the significance of CBCT in the management of trapdoor and blow out orbital floor fractures in children. Further studies are needed to elaborate the utilization of CBCT in the treatment of orbital floor and medial orbital wall fractures. Conclusion: Our study suggests that CBCT has a higher value of specificity and less radiation exposure in the diagnosis of orbital fractures in pediatric age group when there is isolated orbital or mid face trauma, and CT brain is not recommended. Cone Beam CT with multiplanar reconstruction is considered the standard of care in the diagnosis of white eyed blow out orbital floor fractures in the provision of evidenced based healthcare practice. Perioperative CBCT and navigation should be universalized to achieve the best outcome.

Objective To observe the clinical efficacy of surgery for the treatment of orbital floor fractures associated with inferior rectus incarceration. Methods The data of 6 eyes of 6 patients with orbital floor fractures and incarceration of the inferior rectus from Jun. 2013 to Jun. 2014 were analyzed retrospectively. All cases were with diplopia and restriction of upward motility, without enophthalmos, and underwent orbital fracture reduction surgery. The orbital contents protruding into the cavity of the maxillary sinus were returned, and Medpor was implanted for the reconstruction of the inferior orbital wall. Visual acuity, motility and diplopia and CT results pre-and post-operatively were observed and compared. Results All patients were followed up for 3 months. Motility recovered and diplopia disappeared in 5 cases within 2 weeks after injury and 1 patient received surgery more than 2 weeks after injury showed partial improvement of motility and diplopia. Post-operative CT showed the pavimentum orbitae was intact and the inferior rectus reduction. The visual acuity of all patients were not reduced. Conclusion Orbital floor fracture reduction surgery can effectively correct the restricted motility and diplopia of orbital floor fractures and inferior rectus incarceration. Earlier operation might bring more benefits. Key words: Orbital fractures, floor; Inferior rectus incarceration

Orbital fractures: Timing of surgical repair

Orbital floor fractures are common injuries treated by multiple surgical subspecialties. Controversy exists regarding the operative indications. This study sought to correlate radiographic characteristics of orbital floor fractures with validated patient reported outcome measures following non-operative management. Patients who underwent non-operative management of an orbital floor fracture at Yale New Haven Hospital from 2013 to 2018 were queried retrospectively. Patients with GCS < 15 and/or distracting facial soft tissue or bony injuries were excluded from analysis. CT images, demographic information, and FACE-Q patient reported outcomes (Satisfaction with Eyes, Psychological Function, Social Function, and Appearance Related Psychosocial Distress) were reviewed. Statistical analysis was performed with SPSS with statistical significance set at P < .05. Eighteen patients were included in the study. The mean time between injury and completion of the survey was 3.6 years. Fifty-six percent of patients had a right-sided fracture. The mean fracture area was 73.6 mm (Range:15-172 mm), and 913 mm (Range: 0-3106) was the mean volume displaced into the maxillary sinus. The unaffected inferior rectus muscle shape (height/width) was 0.5 (Range: 0.2-0.98) compared to 0.8 (Range 0.4-1.6) for the affected inferior rectus. After controlling for the time interval between survey and injury, gender, income, and education, rounding of the inferior rectus muscle was a significant predictor of appearance related psychosocial distress (P = 0.006). Inferior rectus rounding was stratified into "severe" (75%) and "moderate" (25%) categories. Severe rounding was associated with a larger orbital floor fracture area (110 versus 64 mm; P = 0.074), volume displaced into the maxillary sinus (1,716 versus 610 mm; P = 0.024), and worse appearance-related psychosocial distress (70 versus 25; P = 0.013). Sixty-one percent of patients followed up in clinic with a mean duration of 194 days. Prior studies have correlated presenting radiographic findings to follow-up clinical findings. However, this study is the first to assess long-term outcomes using validated patient-reported questionnaires. Inferior rectus muscle belly rounding significantly correlated with appearance related psychosocial distress. This radiographic finding may be valuable to consider in orbital floor fracture management.

Orbital floor fracture defect size and inferior rectus (IR) rounding index are currently accepted indications for surgery to prevent late enophthalmos. The authors analyzed the positive predictive value (PPV) of these indications. Twenty-eight patients with orbital floor fractures presenting without enophthalmos underwent Hertel exophthalmometry at presentation and at weeks 1, 2, 3, 6, 13, 26, and 52 or more after injury. Orbital defect size and IR rounding index were measured from computed tomographic scans, and PPVs of defects of 1.5 to 2 cm 2 or larger and IR rounding index of 1 or higher for enophthalmos (≥2 mm) were calculated. Nineteen patients had isolated orbital floor fractures (group A), three had noncontinuous orbital floor and medial wall fractures (group B), and six had continuous orbital floor with medial wall fractures (group C). Mean follow-up time was 440 days. Of all patients, 20 had a defect size of 1.5 cm 2 or larger, 12 had a defect of 2.0 cm 2 or larger, and 13 had an IR rounding index of 1 or higher. Of the 28 patients, only one from group A and two from group C developed enophthalmos of 2 mm only. The PPVs of orbital floor defect size of 1.5 cm 2 or larger and 2 cm 2 or larger (groups A and B only) for late enophthalmos were 6.7% and 0%, respectively. The PPV of IR rounding index of 1 or higher for late enophthalmos (all groups) was 0%. For patients with orbital floor fractures presenting without enophthalmos, defects of 1.5 cm 2 or larger and 2 cm 2 or larger, and IR rounding index of 1 or higher, are weakly predictive of late enophthalmos. Furthermore, patients who do not develop enophthalmos within 3 weeks of injury are unlikely to develop significant (>2 mm) late enophthalmos. Risk, III.

Orbital Emphysema

Orbital wall fractures result from external impact injuries which cause an abrupt increase in intraorbital pressure.1 Patients usually present to the emergency room with periorbital swelling and limited eye movements, with or without changes in vision. Relatively common in the Philippines, these fractures are frequently caused by violent assault followed by vehicular accidents involving motorcycles.2 Among 119 maxillofacial trauma cases seen and treated by the Department of Otorhinolaryngology of the East Avenue Medical Center from 2008-2009, 42 were diagnosed as cases of orbital fractures with 36% having concomitant involvement of the orbital floor. Various techniques in diagnosis and treatment developed in the past 20 years, each having its own strengths and weaknesses. The challenge of choosing which among these methods will best achieve the goals of function and aesthetics always confronts surgeons, particularly in a developing country setting. &#x0D; We present a case of bilateral orbital floor fractures with diplopia repaired with conchal auricular cartilage graft in a 22 year old female.&#x0D; &#x0D; CASE REPORT&#x0D; A 22 year old female was immediately brought to our emergency room following a head-on collision with an Asian utility vehicle while driving a motorcycle without a helmet. She was conscious and coherent with stable vital signs.&#x0D; On examination, contusion hematomas were noted over both periorbital areas. Visual acuity was 20/30 OD and 20/40 OS with bilateral limitations of extraocular muscle movement. Bilateral ocular pressures were measured at 14.6 mmHg. Craniofacial CT Scans revealed linear frontal bone fractures with subdural hemorrhages and pneumocephalus in the frontal area, fractures of the calvarial bones, lateral orbital walls, inferior orbital rims and orbital floors (Figure 1). A mannitol drip was started for the hemorrhage.&#x0D; She developed a persistent headache and binocular vertical diplopia with monocular diplopia, OS on the left gaze accompanied by pain on lateral left duction. Visual acuity was 20/25 OU. On the 17th hospital day, she underwent open reduction and internal fixation of multiple facial fractures using titanium plates and screws with reconstruction of both orbital floors using conchal cartilage autografts. The right eye diplopia resolved on the third postoperative day while the diplopia on left lateral downward gaze in the left eye resolved from the ninth postoperative day until the day of discharge.&#x0D; There was complete resolution of diplopia and improvement in visual acuity to 20/20 OD and 20/25 OS on follow up at one year.&#x0D; DICUSSION&#x0D; Orbital floor fractures are relatively common midfacial injuries encountered in urban areas2 and were first described by Smith and Regan in 1957.1 Since then, many articles have been written about their diagnosis and treatment, including indications and optimal time for surgery as well as optimal surgical methods.1 Epidemiological studies reveal that despite different settings, the majority of cases involve the young male population with violent assault as the most prominent etiology accounting for 37.8% of orbital blowout fractures; motor vehicle accidents came in at second with 17.6%.; with the remaining fractures resulting from athletics (14.1%).2 To our knowledge, local reports have not been published but similarities in profile can be deduced.&#x0D; Orbital floor fractures, also known as blowout fractures, imply that the orbital rims have remained intact, whereas one or more walls of the orbit, typically the floor has fractured.3 Orbital floor fractures can be classified into pure and impure according to extent of bone involvement (Table 1). Pure blowout fractures are fractures of the floor not involving the rim while impure blowout fractures have rim extension.3 Pure orbital floor fractures are further classified as trapdoor or non-trapdoor. Trapdoor fractures are those in which either edge of the inferior orbital wall is attached to its original position, while non-trapdoor fractures are those in which the inferior orbital wall is completely separated from its original position and the periorbital tissue has prolapsed into the maxillary sinus1 (Figure 2). These fractures can be also be classified by location: anterior, posterior and anteroposterior1,4 (Figure 3). Our patient presented with non trapdoor type orbital floor fractures measuring 10 x 4 mm on the right and 10 x 5mm on the left.&#x0D; Patients with orbital floor fractures often complain of blurred vision and pain on eye movement. Physical examination also elicits diplopia, accompanying limitation of eye movement and enophthalmos on the affected side. These signs and symptoms are due to (1) herniation of orbital contents with concomitant partial atrophy of extraocular muscles and to (2) an increase in the volume of the orbital cavity with possible compression of the optic nerve.4 Because of these features, orbital floor fractures are classified as both Otorhinolaryngologic and Ophthalmologic emergencies that warrant immediate surgical treatment especially if the patient presents with blurred vision.3,5&#x0D; Confirmatory imaging studies help locate and assess the extent of orbital floor injury. These include radiographs and computed tomography of the facial bones. The commonly used radiograph is the chin-to-nose or Water’s view. This gives a view of the whole orbital area and may reveal a pathognomonic “tear drop” sign, seen as an elliptical opacity underneath the inferior orbital rim, that represents orbital contents, usually orbital fat, that herniated through the fracture.1,3 However, facial computed tomography is still the most useful imaging tool in assessing orbital floor fractures.1,2,3,4 It is usually requested without contrast using 3 different cuts: coronal, axial and sagittal. Coronal cuts reveal discontinuity of the inferior orbital rims with concomitant soft tissue sublaxation; axial cuts present the extent of areas involved while sagittal cuts help locate if the fracture is anterior, posterior or anteroposterior.1,4 &#x0D; The goal of surgical repair in orbital floor fractures is two-fold: to reposition herniated orbital fat and tissue back in the orbit; and to reconstruct the traumatic defect.4 Approaches are via open surgery (subciliary or transconjunctival) or endoscopic (transantral), (Table 2). The open transorbital approach is currently regarded as the mainstream method for reduction of blowout fractures of the inferior orbital wall. It is useful for releasing incarcerated soft tissue, as dissecting all soft tissue around the fracture area is necessary.1 Post operative complications include ectropion and unsightly scars, but these rarely occur in the hands of experienced surgeons.5 Endoscopic repair, usually via a transantral approach, can provide surgeons with several advantages over conventional external repair. These include excellent visualization of the medial and inferior walls of the orbit; easy access to maxillary bone (avoiding or minimizing use of intraocular alloplastic implants); virtual elimination of significantly visible facial scarring and eyelid complications; and performing the procedure under local anesthesia, making intra-operative evaluation of ocular movements and diplopia possible.5,6 A transorbital approach has the advantage of releasing incarcerated orbital tissue, while, in contrast, simply lifting the orbital tissue upward in a transantral approach may aggravate the incarceration1 (Table 2). In this patient, the open approach was used because a mid-facial de-gloving was necessary to access other fractures.&#x0D; The repair of orbital floor fractures involves many techniques, and adequate knowledge and skill is needed to perform any of these techniques employing careful judgment and analysis in formulating a plan that will fit the patient’s needs. As a general principle, the orbital complex is reconstructed by aligning its fractured parts with adjacent stabilized or intact structures.10 Familiarity with the complex shape of the orbital walls is important in repair. In the case of the orbital floor, it gently concaves inferolaterally, turning convex medially to posteriorly, assuming an S-shape configuration. 1,3 The posterior part of the floor is farthest from the inferior orbital rim with the infraorbital nerve coursing thru it makes it vulnerable and weak to the extensive forces absorbed when applied into the orbital area.1,3,10 This explains why posterior orbital floor fractures occur as non-trapdoor types and are difficult to expose. The orbital contents are positioned accurately and precisely into the orbit making any change in volume affect eye function. It is important to assess eye function first as it may give the examiner an idea of the extent of injury to the orbital floor. Indications for repair include diplopia, nonresolving oculocardiac reflex with entrapment (bradycardia, heartblock vomiting, nausea and syncope), fracture involving &gt;50% of the orbital floor, and early enophthalmos or hypoglobus causing facial asymmetry.11 These signs and symptoms elicited during physical examination with documentation of the location of fracture through diagnostic imaging warrant early repair since herniated soft orbital tissue can atrophy within 2-3 weeks post trauma.4&#x0D; The types of grafts/implants used to span the defects of orbital floor fractures are divided into alloplastic and autogenous implants7 (Table 3). Autogenous grafts include bone, cartilage, and fascia. Alloplastic implants can be divided into nonabsorbable types, such as those made of silicone, polytef, hydroxyapatite, tantalum mesh, or titanium, and absorbable types, including those made of polyglactin or gel film. Repair of the orbital floor defect is mandatory if the defect measures at least 50% of the size of the orbital floor bone. The ideal implant must be nonreactive, provide good structural support, be easily positioned, and be readily available.1,2,3,4 In this case the surgeon utilized conchal cartilage grafts. This graft can be used in repairing defects as large as 2 x 2mm. It advantages over other autogenous grafts include having a shape similar to the orbital floor, ease of harvest, malleability and limited morbidity at the donor site.4 &#x0D; Autogenous tissue grafts, i.e. bone or cartilage, are preferred over alloplastic grafts in the repair of isolated orbital fractures similar to this case.10 Grafts (especially bone) should be secured to avoid displacement or migration and improve graft survival. Complete dissection of the fracture is necessary to identity the intact bone on all side of the fracture since these will be used as alignments when placing the graft. In the case of an orbital floor fracture, the posterior portion of the intact bone will serve as a guide to internal orbital reconstruction. The graft should be placed in inclined position just behind the inferior orbital rim to reach the intact posterior bone.3,10 Placing the graft based on correct anatomic position during reconstruction is of more significance rather than using the globe position as basis in volume restoration.10 It is a must to perform duction tests following graft placements and compare these to baseline duction test prior to surgery.9,10 This will help the surgeon distinguish if the stiff duction test is caused by edema from impingement of the musculofibrous ligament system by the graft material.10&#x0D; .&#x0D; Acknowledgement&#x0D; The authors would like to thank Dr Natividad Almazan and Dr. Felix Nolasco for their encouragement and support; and the resident doctors of the Department of ORL-HNS for their help in making this paper.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Orbital Floor Fracture Reconstruction using Conchal Auricular Cartilage Graft

The value of MRI in the diagnosis of acute orbital floor fractures has not been clearly defined. We therefore compared MR findings with CT findings in patients with orbital trauma. In 30 patients with isolated orbital trauma both coronal CT and coronal MRI were used to examine the orbits and the adjacent paranasal sinuses. Visualization of anatomical landmarks, the kind and extent of traumatic lesions, as well as artifacts were scored. The scores were compared using the Wilcoxon matched-pairs signed-rank test. Interexamination agreement between the two methods was calculated using a kappa analysis. All examinations had diagnostic quality: 30 fractures of the orbital floor (9 right and 21 left orbital floor fractures) were identified. In addition, CT showed fractures of the medial orbital wall in 19 patients (63.3%), of the lateral wall in 10 patients (33.3%), of the zygomatic arch in 2 patients (6.7%), and of the maxillary sinus in 4 patients (13.3%). Soft tissue herniation was shown in 13 patients (inferior rectus muscle twice, orbital fat in 11 cases). Magnetic resonance imaging demonstrated soft tissue herniation in 21 patients: muscle in 4, orbital fat in 17 cases. Magnetic resonance imaging is able to demonstrate orbital floor fractures as sensitively as CT, but CT is superior to MRI in showing small and associated fractures; therefore, CT remains in orbital fractures the imaging modality of choice. Magnetic resonance imaging is superior to CT in showing soft tissue herniations; therefore, MRI may have a role as an adjunct to CT if soft tissue entrapment remains unclear.

Orbital floor fractures occur commonly as a result of blunt trauma to the face and periorbital region. Orbital floor fractures with a "trapdoor" component allow both herniation and incarceration of contents through a bone defect into the maxillary sinus as the bone rebounds faster than the soft tissue, trapping muscle, fat, and fascia in the fracture site. In children, the fractured floor, which is often hinged on one side, tends to return toward its original anatomical position due to the incomplete nature of the fracture and elasticity of the bone. The entrapment of the inferior rectus muscle itself is considered a true surgical emergency-prolonged entrapment frequently leads to muscle ischemia and necrosis leading to permanent limitation of extraocular motility and difficult to correct diplopia. For this reason, prompt surgical intervention is recommended by most surgeons. In adults, true entrapment of the muscle itself is not as common because the orbital floor is not as elastic and fractures are more complete. We present an adult patient with an isolated orbital floor fracture with clinical and radiologic evidence of true entrapment of the inferior rectus muscle itself. Despite the delayed surgical repair (4 days after the injury), the patient's inferior rectus muscle function returned to near normal with mild upward gaze diplopia. Inferior rectus entrapment in adults may more likely be associated with immobilization of the muscle without total vascular compression/incarceration significant enough to lead to complete ischemic necrosis.

To describe a series of orbital fractures and associated ophthalmic and craniofacial injuries in the pediatric population. A retrospective case series of 312 pediatric patients over a 9-year period (2002-2011) with orbit fractures diagnosed by CT. Five hundred ninety-one fractures in 312 patients were evaluated. There were 192 boys (62%) and 120 girls (38%) with an average age of 7.3 years (range 4 months to 16 years). Orbit fractures associated with other craniofacial fractures were more common (62%) than isolated orbit fractures (internal fractures and fractures involving the orbital rim but without extension beyond the orbit) (38%). Roof and medial wall fractures were most common (30% and 28%, respectively), followed by orbital floor (24%) and lateral wall (18%) fractures. Orbital roof fractures are the most common fracture in patients <8 years old, whereas orbital floor fractures are the most common fracture in patients older than 8 years. Eighty-seven patients (28%) underwent surgical repair. There is an increasing incidence of surgery in older patients (p = 0.02). Associated neurologic injuries were more common (23%) than associated ophthalmic injuries (20%). Pediatric orbit fracture patterns are dictated by the age of the patient with respect to their craniofacial morphology and mechanism of injury. Orbital roof fractures are more likely to occur in younger patients and not require surgery, whereas orbital floor fractures are more common in older patients and are more likely to require surgery.

Assessment of a Consecutive Series of Orbital Floor Fracture Repairs With the Hess Area Ratio and the Use of Unsintered Hydroxyapatite Particles/Poly l-Lactide Composite Sheets for Orbital Fracture Reconstruction

Image analysis of the inferior rectus muscle in orbital floor fracture using cine mode magnetic resonance imaging.

The impact of orbital floor defect ratio on changes in the inferior rectus muscle and prediction of posttraumatic enophthalmos – A cadaver study