Slipped Muscle Research Articles

Incidence of Strabismus Post–Plaque Brachytherapy in Patients With Uveal Melanoma

PurposeTo determine the incidence and type of strabismus in patients with uveal melanoma treated with plaque brachytherapy. DesignRetrospective incidence estimation study SettingMulticenter Patient Population438 eyes of 438 patients with uveal melanoma treated with plaque brachytherapy between October 2011 to May 2021. InterventionIodine 125 plaque brachytherapy Main Outcome MeasuresVariables reviewed included incidence of non-resolving strabismus post-plaque brachytherapy, type of strabismus developed, extraocular muscles operated, and modality of treatment received. ResultsFour hundred thirty-eight patients underwent plaque brachytherapy treatment for uveal melanoma. Eleven patients developed strabismus post plaque brachytherapy (2.5%, n=11/438). Of these patients, five (1.1%, n=5/438) developed strabismus immediately post-operation. Specifically, two patients (0.5%, n=2/438) developed strabismus immediately post-operation due to slipped muscles, two patients (0.5%, n=2/438) due to decompensated phorias, and one patient (0.5%, n=1/438) due to a fibrotic muscle. Six patients (1.4%, n=6/438) developed late onset sensory strabismus. A total of 355 (81.1%, n=355/438) patients had their extraocular muscles disinserted during surgery, with the lateral rectus being the most common, accounting for 45.4% (n=161/355). Followed by the superior rectus at 26.8% (n=95/355). Strabismus surgery was the most common treatment modality, comprising 72.7% (n=8/11) of patients. ConclusionThe incidence of strabismus following plaque brachytherapy treatment for uveal melanoma was low, and primarily classified as late onset sensory strabismus. Previous studies may underestimate the long-term incidence of strabismus post plaque brachytherapy by focusing primarily on strabismus present immediately post-operatively.

Gradenigo Syndrome: Mimicker of Slipped Muscle and Shunt Failure.

Seeds, Anais BS; Coleman, Sydni L. MD; Strul, Sasha MDEditor(s): Avery, Robert DO; Golnik, Karl C. MD; Froment, Caroline MD, PhD; Wang, An-Gour MD Author Information

Single eye surgery by hang-back recession vs muscle transplantation in large-angle esotropia

Background A two horizontal muscle surgery cannot treat a very large angle of esotropia of more than 80 prism diopters (pd). A single eye surgery would not correct such a large angle. Supramaximal recession and resection would lead to restriction of ocular motility. True muscle transplantations have been tried for this abnormally wide-angle esotropia. Purpose The aim was to compare monocular surgery by hang-back recession vs muscle transplantation, regarding the technique, the expected results, and the possibility of minimizing the risk of complications, such as scleral perforation and a lost or slipped muscle. Patients and methods The study is a prospective and nonrandomized study that was held at the Ophthalmology Department, Al-Azhar University Hospitals, Egypt, during the period between May 2016 and May 2018 on 30 patients presenting with esotropia. A total of 15 patients had undergone medial rectus recession using the hang-back technique and 15 patients had undergone medial rectus recession with muscle transplantation. Conjunctival recession was done at the end of surgery, and lateral rectus resection was done in both groups. Their ages ranged from 4 to 58 years. Overall, 19 patients were males and 11 were females. Results There were nonstatistically significant differences between the two groups in all the follow-up visits. Conclusion True muscle transplantation is a safe alternative option and as effective as hang-back technique for large-angle esotropia. The procedure is stable in the long term, with some motility limitation in maximum adduction.

Clinical and Histopathologic Features of Consecutive Exotropia

ABSTRACTPurpose: The purpose of this study is to investigate clinical and histopathologic features of consecutive exotropia. Methods: Thirty patients with consecutive exotropia and negative forced duction testing underwent unilateral medial rectus resection and advancement. Abnormal scleral attachment (appearance of stretched scar or slipped muscle) was documented and compared with histopathology results. The term “stretched scar” is used when tendon-like scar appears between muscle fibers and scleral attachment. The term “slipped muscle” is used when a thin capsule is attached to the sclera and the muscle fibers retracted posteriorly in the capsule. Histopathologic results of resected medial rectus muscles of 11 control patients were compared with cases of consecutive exotropia. Surgical success was defined as <10 PD deviation at both distance and near, 6 months after the surgery. Dose–response and risk factors for abnormal scleral attachment were also evaluated. Results: Forty percent of the cases had abnormal scleral attachment. Nineteen patients (63%) showed successful results. The mean dose–responses were for near 4.7 and for distance 4.2 prism diopters per millimeters of resection plus advancement. Preoperative medial rectus underaction was a risk factor for abnormal scleral attachment. The mean muscle percentage in pathology was 10 ± 18.7 in patients with abnormal scleral attachment, 28.3 ± 27.9 in other consecutive exotropia patients, and 26.5 ± 30.6 in 11 control eyes. Conclusion: This study showed surgical success of 63% with one-muscle surgery in consecutive exotropia. Calculated dose–responses could be helpful in surgical planning. In the cases with preoperative medial rectus underaction, risk of abnormal scleral attachment is increased.

The Hook and Release Technique During Enucleation Surgery.

To describe the results and potential benefit of direct muscle release from the globe during enucleation surgery without identifying sutures in the rectus muscle insertion sites, a technique referred to as the hook and release technique. Single center, retrospective chart review of patients who underwent enucleation with direct removal of the rectus muscles without identifying sutures in their insertion sites between January 2011 and September 2015 was carried out. The inclusion criteria were primary enucleation without previous strabismus surgery, retinal detachment surgery, or orbital surgery that entered the fibrous connective tissue framework. Forty charts of enucleated patients that had direct release of their extraocular muscles without identifying sutures before releasing them from the globe were identified and reviewed. The primary outcome measure was intraoperative or immediate postoperative complications. This retrospective chart review was performed with research ethics board approval and in compliance with the Declaration of Helsinki. Data show that following the hook and release technique, the rectus muscles were easily located and reconnected to the orbital implant wrap. The oblique muscles were not reattached. In each of the 40 patients, the 4 rectus muscles were easily located by gently applying traction anteriorly at the conjunctiva/Tenons' edge using double-pronged skin hooks. There was no instance of a lost or slipped muscle following the hook and release technique. The hook and release technique is a simple and efficient method to remove the 4 rectus muscles from the globe and still easily locate them. They are not "lost" and do not "slip out of position" but held in place by the orbital connective tissue framework and the extraocular muscle pulley system. This technique has been very helpful teaching resident staff how to do enucleation surgery as it avoids the more time consuming placement of double-armed locking sutures through the rectus muscle insertions and the potential risk of globe penetration while the muscles remain attached to the eye. If the surgeon desires to attach the muscles to the orbital implant, then sutures are passed after the eye is removed, thus eliminating the worry of globe penetration and avoiding accidentally cutting preplaced extraocular muscle sutures during the remaining enucleation procedure.

Slipped extraocular muscles: characteristics and surgical outcomes

ObjectiveTo study the frequency and characteristics of slipped extraocular muscles after strabismus surgery and report the postoperative outcomes longitudinally. DesignRetrospective chart review. ParticipantsElectronic medical records of 493 patients who underwent strabismus surgery and were found to have a slipped muscle intraoperatively were reviewed. MethodsRecords were retrieved and operative reports were screened for the presence of slipped muscles. Data pertaining to the eye examination and surgery were collected, including vision, ocular motility in all positions, duction limitations, slipped muscle, empty sheath length, amount of slippage, amount of advancement, and amount of recession of the antagonist muscle. ResultsTwelve patients (mean age 29.1 ± 6.4 years; 5 males) were found to have 15 slipped medial rectus muscles. Average amount of slippage was 15.7 ± 2.0 mm; from limbus empty sheath length was 5.9 ± 1.9 mm. Average preoperative deviation was 32.2 ± 10.0 prism diopters (PD) exotropia. Mean follow-up after corrective surgery was 13.3 months (1 week to 42 months). Four patients were transiently overcorrected postoperatively (7.0 ± 7.0 PD esotropia). The rest had mean residual exotropia of 13.5 ± 9.2 PD with a change of 26.6 ± 10.3 PD from baseline (p < 0.001). Intraoperative mean muscle movement was 10.3 ± 2.2 mm with a mean postoperative change of 2.6 PD for each 1 mm of muscle advancement. There was no significant increase over time in the postoperative angle of deviation during all follow-up periods except for 1 patient who was re-explored after 4 years. ConclusionsSlipped muscle should be suspected in the presence of limited ductions and consecutive deviations after strabismus surgery. A change of 2.6 PD for every 1 mm of medial rectus muscle advancement was observed and maintained over time.

Classifying medial rectus muscle attachment in consecutive exotropia

To evaluate interexaminer agreement in classifying medial rectus muscle attachment in patients with consecutive exotropia. A series of intraoperative photographs of 26 eyes in 25 patients who underwent surgery for consecutive exotropia were retrospectively studied. Two examiners independently classified the medial rectus attachment as either normal, stretched scar, slipped muscle, or lost muscle. Agreement between examiners was evaluated using the weighted kappa (κ) statistic, and causes of disagreement were assessed. Agreement was found in 15 of 26 eyes (58%), signifying "moderate" agreement (κ=0.41). Approximately two-thirds of the disagreements, 7 of 11 eyes (64%), were between stretched scar and slipped muscle, with characteristics of each entity being present in the same muscle. The clinical distinction between stretched scar and slipped muscle appears to be obscure. We propose that they should be considered a single entity, which could be referred to as "abnormal scleral attachment."

Characteristics and surgical outcomes of consecutive exotropia of different etiologies.

To investigate the surgical results for consecutive exotropia with or without insertion abnormalities on the basis of the position of the lateral rectus muscle at surgery. Patients with consecutive exotropia who had undergone medial rectus recession as a primary procedure or advancement of previously recessed medial rectus muscles from 2002 to 2012 were included in the study. The characteristics, postoperative courses, and final results were compared among 3 patient groups. The patients' characteristics including sex, refractive error, and age at the initial surgery were compared. The main outcome measures were the angles of deviation in the primary position and the average divergent drift per month after the exotropia surgery. Twenty-four eyes of 23 patients were investigated. The patients were divided into 3 groups according to insertion status: with normal muscle insertion (4 men, 4 women), slipped muscles (9 women), and stretched scars (2 men, 4 women). The preoperative angles of deviation at near differed significantly between the slipped muscle group and the normal muscle insertion group (P = 0.02). Only patients with normal insertions had significantly greater hyperopia in the nondominant eye (0.95 D) than in the dominant eye (0.53 D). The postoperative divergent shift per month was similar among the groups (0.3, 0.1, and 0.2 prism diopters per month in the slipped muscle, stretched scar, and normal muscle insertion groups, respectively; P = 0.70). Hyperopic anisometropia is an important factor in the natural course of outward drift. The postoperative course of advancement of the medial rectus muscle was equally stable in all 3 patient groups.

What information can we give to the patient about the risks of strabismus surgery.

I hope to report the type, incidence, and clinical outcomes of severe complications from strabismus surgery in the United Kingdom and to help in the discussions involved in the consent process. The main part of the talk will revolve around a BOSU (British Ophthalmic Survey Unit) investigation. Cases were identified prospectively between 1 September 2008 and 31 August 2010. Questionnaire data were requested at the time of the complication recognition and at 6 months' follow-up. Outcome was graded I-V, with a poor or very poor outcome meaning either loss of corrected visual acuity or primary position double vision. A total of 60 completed reports of adverse events and complications were received during the study period. During the same time, ∼24 000 strabismus surgeries were carried out in the United Kingdom, yielding an overall incidence of 1 in 400 operations (95% binomial confidence, 1 per 333-500 operations). The most commonly reported complication was perforation of the globe (19 (0.08%)), followed by a suspected slipped muscle (16 (0.067%)), severe infection (14 (0.06%)), scleritis (6 (0.02%)), and lost muscle (5 (0.02%)). Overall, complications were reported in adults and children in equal numbers; however, scleritis was significantly more common in adults. A poor or very poor clinical outcome was recorded as 1 operation per 2400. The study limitations are as follows: the denominator was extrapolated from the number of surgeries in England, and there was an almost certain underreporting of cases. Complications with the potential for a poor outcome are relatively common, but the final clinical outcome is good in the majority of cases.

Surgical results of the slipped medial rectus muscle after hang back recession surgery.

To analyze the surgical results of a slipped medial rectus muscle (MRM) after hang back recession surgery for esotropia. Twenty-one patients who underwent re-exploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle. Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant. Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients. The average age of 21 patients who had consecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y (5-50y). The average duration between the first operation and the diagnosis of the slipped muscle was 25mo (12 to 36mo). The mean follow up after the corrective surgery was 28mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was -2.26 (ranging from -1 to -4). All patients had full adduction postoperatively. The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.

Traumatic avulsion of extraocular muscles: case reports

We described the clinical, surgical details and results (motor and sensory) of the retrieving procedure of traumatically avulsed muscles in three patients with no previous history of strabismus or diplopia seen in the Department of Ophthalmology, State University of Campinas, Brazil. The slipped muscle portion was reinserted at the original insertion and under the remaining stump, which was sutured over the reinserted muscle. For all three cases there was recovery of single binocular vision and stereopsis.

New strabismus surgical techniques

Five new strabismus surgical procedures were developed by the authors and were presented as a workshop at the AAPOS annual meeting of the American Association for Pediatric Ophthalmology and Strabismus. They are summarized here to introduce these methods to the reader and provide surgeons with more options in approaching difficult strabismus problems. Diagnosis and correction of consecutive strabismus attributable to stretched scar is discussed. The pulley posterior fixation procedure is a unique approach to correct high accommodative convergence or to augment a maximal medial rectus recession. Diagnosis and repair of the partial avulsion (flap tear) of a rectus muscle allows correction of some restrictive strabismus following blunt trauma. The nasal myectomy of the inferior oblique muscle corrects persistent inferior oblique overaction without sacrificing the tether effect gained by a previous anterior transposition of the inferior oblique. The full advancement of the superior oblique tendon offers another option to strengthen a weak superior oblique muscle.

Severe complications of strabismus surgery

To determine the type, incidence, and clinical outcomes of severe complications from strabismus surgery in the United Kingdom. Cases were identified prospectively through a national surveillance unit between September 1, 2008, and August 31, 2010. Questionnaire data were requested at the time of the complication recognition and at 6 months' follow-up. Outcome was graded I to V, with a poor or very poor outcome meaning either loss of corrected visual acuity or primary position double vision. A total of 60 completed reports of adverse events and complications were received during the study period. During the same time approximately 24,000 strabismus surgeries were performed in the United Kingdom, yielding an overall incidence of 1 in 400 operations (95% binomial confidence, 1 per 333-500 operations). The most common reported complication was perforation of the globe (19 [0.08%]), followed by a suspected slipped muscle (16 [0.067%]), severe infection (14 [0.06%]), scleritis (6 [0.02%]), and lost muscle (5[0.02%]). Overall, complications were reported in adults and children in equal numbers; however, scleritis was significantly more common in adults. A poor or very poor clinical outcome was recorded as 1 operation per 2,400. This study provides an assessment of the overall risks associated with strabismus surgery in the United Kingdom. Complications with the potential for a poor outcome are relatively common, but the final clinical outcome is good in the majority of cases.

Magnetic Resonance Imaging of the Medial Rectus Muscle of Patients with Consecutive Exotropia after Medial Rectus Muscle Recession

To investigate the morphologic characteristics of the medial rectus muscle in patients with consecutive exotropia. Retrospective, nonrandomized, interventional study. Eleven eyes of 10 patients with consecutive exotropia were studied. Thirteen eyes of 13 age-matched normal subjects were studied as controls. All of the patients underwent an advancement of a previously operated medial rectus muscle. Patients were divided into 3 groups based on the insertion of the medial rectus muscle: Normally recessed stretched scar, and slipped muscle. A comparison was made of the clinical findings, intraoperative findings, and distance from the limbus to the medial rectus muscle measured on magnetic resonance images among the groups. The medial rectus of 4 eyes of 3 patients had normally recessed insertions and 7 eyes had abnormal insertions (3 stretched scars, 4 slipped muscles). The clinical findings were not different among the 3 groups. The magnetic resonance images showed that the medial rectus muscle was located closest to the limbus in the control subjects and most distant in the patients with a slipped muscle (P<0.005). The clinical findings in the patients with a stretched scar and with normally recessed were indistinguishable. Magnetic resonance images of the medial rectus muscles of the control subjects and operated groups are significantly different morphologically. A slipped medial rectus muscle has characteristic magnetic resonance findings that are distinguishable from the muscle with normally recessed and stretched scar.

Midoperative Forced Duction Test as a Guide to Titrate the Surgery for Consecutive Exotropia

This is a retrospective study of the outcome of all consecutive exotropia surgery performed between the years 1999 and 2007. Excluded were cases of slipped muscles, muscle transpositions, and concurrent cyclovertical procedures. A total of 135 patients of mean age 40 years (range 6–72) were operated with a mean preoperative angle of deviation −40Δ (range −12 to −90). Five were treated with fixed sutures and the rest with adjustables. The surgery included preplanned lateral rectus recessions of mean 6 mm (range 2–9) and maximal possible medial rectus advancements with or without resections of mean 5.6 mm (range 2–11), intraoperatively adjusted to give a resistance of +1 to +2 for abduction on forced duction test (FDT). Adjustable suture patients were seen 4 to 6 hours after surgery and underwent further adjustment, if needed, to achieve the target angle. A further review took place at 2 weeks and 2 months. Children remained under follow-up till 8 years of age. Forty percent needed postoperative adjustment. The mean postoperative angle at final measurement was −2Δ (range +25 to −45). Eighty percent achieved an angle within 10Δ of orthotropia. No gross restrictions of ductions were present postoperatively.

Adjustment of the surgical nomogram for surgery on slipped extraocular muscles

A slipped muscle is an underdiagnosed complication of strabismus surgery. Surgery necessitates intraoperative diagnosis, measurement, and resection of the empty sheath. We analyzed the results of empty sheath surgery for slipped medial and lateral rectus muscles in a large cohort of patients. Eighty-five patients who underwent empty sheath surgery at a secondary referral center by a single strabismologist were included in the study. We retrospectively analyzed the preoperative and postoperative change in angle of deviation 6 weeks after surgery. All cases were reoperations in which an unexpected or unsatisfactory outcome followed primary surgery. Consecutive exotropias with slipped medial rectus muscles were noted in 68 patients. There were 17 esotropia cases with lateral rectus muscles slip, of which 2 were consecutive exotropias that became consecutive esotropias. Bilateral medial rectus muscle slips were found in 6 patients with consecutive exotropias. Adjustable suture surgery was performed in 27 patients. Resection of the empty sheath of the slipped medial or lateral rectus muscle with advancement to the original site of insertion was done in all cases; in addition, the antagonist muscle was recessed only if it was tight. The total muscle advancement was calculated in millimeters from the total amount of sheath resected, muscle advanced, and the antagonist recessed. The greater the preoperative deviation, the more surgical muscle advancement was required and the greater the change in postoperative angle of deviation. Mean change in angle of deviation was 3.13(delta) for each millimeter of muscle advancement (median = 3.00, SD = 1.72). The diagnosis of slipped muscle should be confirmed during strabismus surgery. The empty sheath was measured, resected, and the muscle advanced to the original site of insertion. An approximate 3(delta) change in angle of deviation was observed for every millimeter of muscle of advancement. For very large and very small deviations, surgeons should modify this to an accustomed measurement dictated by their experience.

Augenmuskeloperationen bei endokriner Orbitopathie - Dosis-Wirkungs-Beziehung und funktionelle Ergebnisse

Strabismus in thyroid ophthalmopathy is based on a loss of the contractility and distensibility of the external ocular muscles. Different therapeutic approaches are available, such as recession after pre-. or intraoperative measurement, adjustable sutures, antagonist resection, or contralateral synergist faden-operation. 26 patients with strabismus in thyroid ophthalmopathy were operated between 2000 and 2003. All patients were examined preoperatively, then 1 day and 3 - 6 months (maximum 36 months) postoperatively. Before proceeding with surgery, we waited at least 6 months after stabilization of ocular alignment and normalization of thyroid chemistry. Preoperative vertical deviation was 10-44 PD (mean 22), 3 months postoperatively it was 2-10 PD (mean 1.5). Recession of the fibrotic muscle leads to reproducible results: 3.98 +/- 0.52 PD vertical deviation/mm for the inferior rectus. In the case of a large preoperative deviation a correction should be expected, which might not be sufficient in the first few days or weeks; a second operation should not be carried out before 3 months. 7 patients were operated twice, 1 patient need three operations. 4 patients (preop. 0) achieved no double vision at all; 15 patients (preop. 1) had no double vision in the primary and reading positions; 3 patients (preop. 0) had no double vision with a maximum of 5 PD; 1 patient (preop. 7) had double vision in the primary or reading position even with prisms; and 2 patients (preop. 17) had double vision in every position. We advocate that recession of the restricted inferior or internal rectus muscle is precise, safe and effective in patients with thyroid ophthalmopathy. The recessed muscle should be fixed directly at the sclera to avoid late over-correction through a slipped muscle. The success rate in terms of binocular single vision was 76 % and 88 % with prisms added.

Histology of a Slipped Muscle After Strabismus Surgery

A complication of strabismus surgery is a slipped muscle. We present a patient who suffered such a complication following surfical correction of strabismus. The resected part of the slipped muscle was histopathologically examined. Fibrovascular connective tissue was found in the specimen with no muscle fibers in it.

Slipped and lost extraocular muscles.

A slipped or lost muscle should be considered in the differential diagnosis of a patient presenting with a marked limitation of duction and inability to rotate the eye beyond the midline. Loss of a rectus muscle can occur after strabismus surgery, trauma, paranasal sinus surgery, orbital surgery, or retinal detachment surgery. The extraocular rectus muscle most frequently slipped or lost is the medial rectus muscle. Forced ductions, active force generation, saccadic velocity studies, differential intraocular pressure measurements, and orbital imaging studies may aid in identifying a slipped or lost muscle. However, no single diagnostic test provides absolute reliability for determining a lost muscle. Slipped muscles develop when the muscular capsule is imbricated without including the muscle or muscle tendon during strabismus surgery. When the capsule is reattached to the sclera, the tendon and muscle are then free to slip posteriorally from the site of attachment. Slipped muscles are retrieved by following the thin avascular muscle capsule posteriorally until the muscle is identified. A lost muscle can be found using a traditional conjunctival approach, by an external orbitotomy, or by an endoscopic transnasal approach. Although many diagnostic maneuvers are useful in identifying a lost rectus muscle, the oculocardiac reflex is the most important. Once the lost muscle is identified, the muscle should be imbricated with a nonabsorbable synthetic suture and securely reattached to the globe.

Scar remodeling after strabismus surgery

Purpose: We sought to investigate abnormal scar lengthening after strabismus surgery. Methods: Patients with overcorrection after strabismus surgery or undercorrection after extraocular muscle resection underwent exploration of previously operated muscles. Abnormal findings were documented by inspection and photography, and repair was undertaken at first with absorbable sutures and later with nonabsorbable sutures. Results: Lengthened scars, consisting of amorphous connective tissue, were repaired on 198 muscles in 134 procedures by excision of the scar and reattachment of the muscle to sclera; absorbable sutures were used in 64 procedures, and nonabsorbable sutures were used in 70 procedures. Thirty-one procedures were followed by partial recurrence of the original overcorrection; 7 of these had documented restretching. The use of nonabsorbable sutures decreased the recurrence of strabismus from 42% to 6%. Factors that distinguished patients with stretched scars from patients with classic slipped muscles included minimal or no limitation of versions, less separation of the tendons from sclera, and thicker appearance of the scar segments. Conclusions: A lengthened or stretched remodeled scar between an operated muscle tendon and sclera may contribute to variability of outcome after strabismus repair, even years later. Definitive repair requires firm reattachment of tendon to sclera with nonabsorbable suture support. (J AAPOS 2000;4:326-33)