STRABISMUS MANAGEMENT AFTER ORBITAL BLOWOUT FRACTURE

Orbital floor fractures (OBF) account for 40% of mid-facial injuries and are therefore the most common of all trauma injuries in this region. The post-treatment complication that often follows orbital floor repair is residual diplopia or 1 persistent diplopia and is seen in 86% of the OBF cases. The causes for persistent diplopia can be varied and is often related to the degree of inflammation, trauma to 2 musculature, fat or nerves and surgical timing. Some of the common causes of the same are - malpositioning of the globe, fibrosis of the inferior fibro fatty muscular complex following trauma, direct damage to an extraocular muscle (commonly inferior rectus muscle), local injury to a motor nerve, ischemia (or compartment syndrome), iatrogenic damage during reconstructive surgery or entrapment under improperly placed alloplastic material. Our case report mentions a rare case of persistent vertical diplopia even after successful repair of orbital blowout fracture. A 15-year-old male patient following a road traffic accident presented with persistent headache and vertical diplopia. The patient was evaluated by a oral maxillofacial surgeon and a presumptive diagnosis of a case of large orbital floor fracture with entrapment of inferior rectus muscle was made which was confirmed on CT Scan. He was managed surgically by reduction of the fracture and fixation with a titanium mesh. 2 weeks post-surgery he reported to the squint clinic with complaints of persistent double vision. On comprehensive ocular examination, it was found that patient had vertical diplopia with limitation of infraduction in the left eye with negative FDT, on re-evaluation of MRI scans with 1 mm cuts, a partial left inferior rectus tear was seen and documented as the cause of persistent diplopia. Patient was treated conservatively by prescribing prismatic glasses with fusional exercises. After 6 months of follow up, the patient was relieved of diplopia in primary position but there was a residual hypotropia in downgaze for which he was prescribed prisms only for downgaze.

Correlation between Thyroid-stimulating Antibody Level Change and Extraocular Muscle Thickness Change in Thyroid Eye Disease

Purpose: To investigate the changes in extraocular muscle thicknesses by variations in the thyroid stimulating antibody (TSAb) level in patients with thyroid eye disease (TED).Methods: A total of 67 TED patients were enrolled. They were divided into two groups: an experimental group with clinically significant elevated TSAb levels (≥140 IU/L) and a control group (TSAb <140 IU/L). All of the lateral, medial, superior, and inferior rectus muscle thicknesses were measured with the aid of anterior segment optical coherence tomography (OCT). The average thicknesses for both eyes were recorded for each patient based on the values measured at the ends of the muscles (which become vertically thinner from the points of tendon attachment). We measured changes in TSAb levels and extraocular muscle thicknesses after two follow-up periods and sought correlations among these parameters.Results: At the initial visits, the inferior rectus muscle thickness was positively correlated with the TSAb level in the experimental group (p = 0.045, r = 0.478). None of the medial, superior, or lateral rectus muscle thicknesses were so correlated. On follow-up, the variation in TSAb level correlated negatively with changes in lateral rectus muscle thickness (p = 0.038, r = -0.357). The superior rectus muscle thickness tended to be negatively correlated with the TSAb level, but statistical significance was not attained (p = 0.146, r = -0.669). The thicknesses of the inferior and superior rectus muscles did not change over time.Conclusions: In TED patients, TSAb variations seem to reflect the extent of periorbital tissue edema, thus correlating negatively with especially lateral rectus muscle thickness changes.

Absent Bell’s phenomenon in patients with thyroid eye disease

Background To investigate the incidence of absent Bell’s phenomenon (BP) and the relationship between absent BP and inferior rectus muscle hypertrophy and other clinical features in patients with thyroid eye disease (TED). Methods A total of 104 patients who were first diagnosed with TED between January and December 2014 were included. Inferior rectus muscle area and associations with clinical features of TED and thyroid function test including thyroid specific antibodies were compared between patients with TED with and without BP. The volume of the inferior rectus muscle was calculated by adding up all the cross-sectional areas measured on sagittal CT images. Results Among the 104 patients, 14 had absent BP (13.5%), 12 with bilateral and two with unilateral. There was no significant difference in thyroid function test, presence of TSIs, exophthalmos, or volume of inferior rectus muscle measured in CT scans (P > 0.05). Incidence of diplopia, elevation limitation, and upper eyelid retraction were risk factors of absent BP in TED patients (by logistic regression analysis, P < 0.05). Conclusions Inferior rectus muscle hypertrophy was not the cause of absent BP in TED patients. Fibrosis and tightening of the inferior rectus muscle, lower eyelid, and surrounding orbital tissues, rather than inferior rectus muscle hypertrophy, might be related to absent BP in TED patients.

Recurrent unilateral restrictive elevation deficit in childhood: a tailored approach

Monocular elevation deficiency poses a challenge to strabismus surgeons on account of its varied clinical presentations as well as management which often needs a tailored approach. We report on a young child who presented to us at 6 months of age with a clinical course marked by primary involvement of the inferior rectus muscle in one eye causing restricted elevation in all gazes and complete relief of hypotropia following disinsertion of the affected muscle but followed by recurrence and additional procedures (antimitotic application and superior rectus plication) for the same. She followed a recalcitrant clinical course which was marked by multiple recurrences requiring a tailored approach and finally managed successfully with a follow-up of 3 years, by now. This case demonstrates the almost intractable nature of restrictive pathology involving a single muscle warranting multiple surgeries and a close follow-up with good surgical outcome.

New Extraocular Muscle Entrapment after Facial Fracture Repair

Extraocular muscle entrapment is a well-recognized complication of orbital fracture, wherein the inferior rectus muscle becomes lodged within the fracture fragments at the time of the initial trauma. New onset entrapment cannot occur without new force applied to the orbit, displacing the fragments and the inferior rectus. Theoretically, in complex orbital fractures, manipulation of disjunct fragments may apply pressure to the orbital contents and induce new entrapment in an otherwise non-operative orbital floor fracture. Here we present the only described case of new extraocular muscle entrapment after open reduction and fixation of a supraorbital rim and frontal sinus fractures and emphasize the need for careful assessment after repair of such a fracture to ensure that new entrapment has not occurred.

A single inferior rectus muscle surgery for treatment of congenital superior oblique palsy with small deviation in primary position

Purpose: To evaluate outcomes of one muscle surgery for treatment of congenital superior oblique palsy (SOP) with Knapp Class V. Methods: Medical records were retrospectively reviewed for the patients with the congenital SOP type V who underwent surgical treatment through one muscle surgery between July 2015 and September 2020. The surgical procedure was resection-recession on the contralateral inferior rectus muscle of the hypertrophic or paretic eye. Vertical alignment at nine cardinal gaze positions, and resolution of the abnormal head posture were evaluated pre- and postoperatively. The follow-up was scheduled regularly at postoperative day 1, 1 week, 1 month, and followed by 2-month intervals until 18 months. Results: Twelve patients were included in this study, with a mean age of 6.4 years (range from 3 to 10 years). The mean follow-up period was 10.5 months after surgery (range from 6 to 18 months). The average vertical deviation at primary position was 6.33△ ± 2.93△ preoperatively and 0.75△ ± 1.14△ postoperatively ( p < 0.05). The average vertical deviation at downgaze was 23.33△ ± 4.75△ preoperatively and 1.92△ ± 1.62△ postoperatively ( p < 0.05). All patients had an abnormal head position preoperatively. Postoperative results indicated that the patients’ abnormal head position had been improved significantly. Conclusions: The surgical procedure of resection-recession on a single inferior rectus muscle is a successful intervention for the correction of superior oblique palsy (SOP) with Knapp Class V.