Medial Rectus Research Articles

Surgical Outcomes of Unilateral One-muscle Surgery in Basic Intermittent Exotropia with Larger Near Deviation

Purpose: To compare the postoperative changes between unilateral medial rectus resection and lateral rectus recession and evaluate surgical outcomes of unilateral one-muscle surgery in basic intermittent exotropia under 25 prism diopters (PD) with a larger near than distance deviation.Methods: This study was conducted on patients with basic intermittent exotropia under 25 PD and a larger near than distance deviation. A retrospective analysis was conducted on 23 patients who underwent unilateral medial rectus resection (Group 1) and 32 patients who underwent unilateral lateral rectus recession (Group 2) as primary surgery. The angle of deviation at near and distance was measured at 1 week, 1 month, 3 months, 6 months, and 1 year postoperatively. Surgical success was defined as within 4 PD of esophoria or 10 PD of exophoria at 1 year after surgery.Results: The mean preoperative deviation angle was 20.18 ± 2.55 PD for Group 1 and 19.30 ± 2.77 PD for Group 2, while the mean near-distance disparity was 6.83 ± 2.67 PD for Group 1 and 5.18 ± 1.56 PD for Group 2. At 1 year postoperatively, the mean distance deviation angle was 9.43 ± 5.82 PD for Group 1 and 5.94 ± 6.49 PD for Group 2. The mean near-distance disparity at 1 year was 0.91 ± 3.96 PD for Group 1 and 0.81 ± 2.07 PD for Group 2. The success rates at 1 year were 65.2% for Group 1 and 72.7% for Group 2 (<i>p</i> = 0.362). Both groups showed effective reductions in the postoperative angle of deviation and near-distance disparity with no significant difference between the groups.Conclusions: Unilateral medial rectus resection and lateral rectus recession both effectively manage basic intermittent exotropia under 25 PD with larger near than distance deviation as the primary surgery.

Isolated hydatid cyst in the medial rectus muscle: unveiling a rare orbital occurrence.

Orbital hydatid disease, while rare, should be included in the differential diagnosis of unilateral proptosis, particularly in endemic areas. Accurate diagnosis and comprehensive management are essential for effective treatment and favorable long-term outcomes. A 12-year-old boy presented with a one-month history of diplopia and left-sided proptosis. A CT scan revealed a cystic mass within the left medial rectus muscle. Surgical intervention confirmed the presence of a hydatid cyst following cyst rupture and irrigation with hypertonic saline. The patient underwent a two-month course of albendazole therapy. Initially, the patient experienced persistent exotropia and diplopia, but at the three-year follow-up, he exhibited no diplopia or proptosis and only mild residual exotropia. This case underscores the importance of considering orbital hydatid cysts in the differential diagnosis of unilateral proptosis in endemic regions. Heightened awareness, accurate diagnosis, and a tailored therapeutic approach, including surgical removal and antiparasitic treatment, are crucial for successful management and improved long-term outcomes.

Wall-Eyed Internuclear Ophthalmoplegia: History and Hypothesis.

Most patients with internuclear ophthalmoplegia (INO) are orthotropic, although a subset is exotropic. When INO is bilateral, this is termed wall-eyed bilateral internuclear ophthalmoplegia (WEBINO). In 1979, Sharpe described his "first case" of wall-eyed monocular internuclear ophthalmoplegia (WEMINO) as "a unique clinical syndrome" characterized by unilateral INO and ipsilateral exotropia. WEMINO was clinically identified in seven patients, with oculographic correlation in six and neuropathological confirmation in one. Oculographic features of exotropic INO patients were compared with those of six orthotropic INO patients using magnetic search coil and infrared oculography. All clinically defined WEMINO patients showed slowed, hypometric ipsilateral saccades by oculography. Six patients had ipsilateral exotropia, and three had ipsilateral hypertropia. Ipsilateral abducting saccades had faster peak velocities for smaller saccades, more so for orthotropic patients. Exotropic patients had normal sinusoidal mean vestibulo-ocular reflex (VOR) gains and phases; orthotropic patients had subnormal mean VOR gains and phase leads. WEMINO is a clinical ocular motor syndrome characterized by unilateral slow, hypometric adducting saccades with exotropia and hypertropia of the ipsilateral eye. We propose that it results from discrete unilateral damage to burst-tonic fibers in the medial longitudinal fasciculus (MLF) with sparing of the adjacent extrafascicular pathways. Paradoxically, orthotropic INO results from more extensive damage to ascending pathways lateral, ventral and caudal to the MLF. Direct injury to the medial rectus subnucleus is not required. This manuscript was in preparation at the time of Dr Sharpe's death in 2013 and is an acknowledgement of his forward-thinking, as his hypotheses have stood the test of time.

An evaluation of 30 years’ experience in the use of botulinum toxin injections in the management of sixth nerve palsies

ABSTRACT Intrroduction Sixth nerve palsy is the most common type of extraocular muscle palsy. The therapy options in sixth nerve palsies include monitoring with or without conservative treatment, botulinum toxin injections or strabismus surgery. The aim of this retrospective study was to compare botulinum toxin (BT) injections into the medial rectus to conservative treatment in sixth nerve palsies. The rate of patients improved after intervention and treatment outcomes for the two treatment options were be evaluated at a German tertiary referral center. Methods A service evaluation was conducted on adult patients with sixth nerve palsy. Patient files were reviewed and data including abduction deficit and size of deviation were collected retrospectively. Patients which presented between January 1987 and April 2022 were considered. Patients were allocated into two treatment groups: BT injected into medial rectus or conservative treatment, which included observation, providing occlusion and Fresnel prisms. Inclusion criteria were attendance of two visits with orthoptic assessment. Exclusion criteria included presence of further oculomotor palsies, strabismus, strabismus surgery and suppression. Non-parametric statistical analysis was conducted using IBM® SPSS Statistics. Results A total of 606 adult patients with unilateral or bilateral sixth nerve palsy attended during the named period. A total of 137 adult patients met the inclusion criteria. Of which, 36 had a bilateral palsy, 101 had a unilateral palsy. 45.26% (n = 62) were treated with BT injections and 54.75% (n = 75) were treated conservatively. The median initial abduction deficit was greater in the BT group, (−4 to −5 after Scott and Kraft) than in the conservative treatment group (−1). The initial angle of deviation at distance was significantly larger in the BT group than in the conservative treatment group (p = <0.001). The rate of improvement in the BT group was 24.19% (n = 15) and 20% (n = 15) in the conservative treatment group. When excluding longstanding palsies rates of improvement in both groups increased to 28.85%. The improvement of the angle of deviation at distance in all patients was greater in the BT group (p = <.001). The improvement of abduction in bilateral palsies were greater in the BT group (p = .016), but in unilateral palsies, there was no significant difference in abduction improvement in the two treatment groups (OD p = .3, OS p = .406). Conclusion This service evaluation found that BT injection into medial rectus in unilateral and bilateral sixth nerve palsies did not increase the rate of improvement compared to conservative treatment. But BT injections reduced the angle of deviation to a greater extent than conservative treatment. Additionally, BT was able to improve abduction in bilateral palsies to a greater extent than conservative treatment. It is recommended a BT injection is considered in symptomatic bilateral sixth nerve palsies to enable fixation and improved ocular motility. More research is needed to verify reliable clinical guidelines for the use of BT in sixth nerve palsies.

Sinus mucocele leads to unilateral proptosis in an infant patient with cystic fibrosis; a literature review and a case report study

Introduction and Importance: Cystic fibrosis (CF) is a widespread life-shortening recessive genetic disease and can present with sinus mucocele. Sinus mucocele is a rare condition, with limited prevalence data on unilateral proptosis. Case presentation: We present a case of a 19-month-old boy with CF who experienced worsening proptosis and exotropia in his right eye. A brain and orbit MRI revealed diffuse polypoid mucosal thickening, possible dense fungal deposit, deformity of the mid face, especially on the right side, with more prominent bulging of medical and inferior walls of the right lobe, a right ethmoidal mucocele causing ocular globe displacement, medial rectus compression, and optic nerve. An examination of the eye fundus showed disc edema and vascular congestion. Endoscopic sinus surgery successfully drained the mucocele, and treatment with antibiotics and corticosteroids led to symptom improvement and resolution of proptosis within three weeks. Clinical Discussion: Mucoceles represent an uncommon complication associated with CF in pediatric patients. Consequently, any child presenting with this issue should undergo evaluation for CF. Investigating this infrequent condition’s underlying mechanisms and consequences may improve treatment approaches and outcomes for those impacted. Conclusion: Sinus mucocele with unilateral proptosis in CF patients is uncommon, and endoscopic sinus surgery appears to be an effective cure for this complication, even in the pediatric population at high risk, like CF patients.

Clinical significance of medial rectus tendon width in unilateral medial rectus resection for patients with previously recessed lateral rectus muscle for exotropia

Clinical significance of medial rectus tendon width in unilateral medial rectus resection for patients with previously recessed lateral rectus muscle for exotropia

Orbital Myositis and Strabismus: Clinical Profile, Management, and Predictive Factors for Recurrence.

To study the clinical profile of patients with orbital myositis and their management modalities and predictive factors for recurrence. The records of all consecutive patients diagnosed as having orbital myositis from 2010 to 2022 were reviewed. Patient demographics, presenting complaints, visual function, primary gaze deviation, and extraocular muscle involved were studied in the clinical profile. The radiological modalities and their management along with the recovery status and need for surgical intervention were documented. Fifty-two patients (55 eyes) (69% women) were diagnosed as having orbital myositis with a mean age of 36 ± 16 years presenting with periocular pain (55%) followed by diplopia (49%). Disease was unilateral in 94%. Sixty percent had ocular misalignment in primary gaze. The medial rectus was the most involved muscle (58%), with abduction limitation in 73%. Computed tomography (42%), magnetic resonance imaging (42%), and combined imaging (16%) were used in localizing the disease. Muscle biopsy was done in 38% of patients. Systemic immunomodulators were required in 16%. Strabismus surgery was planned in 15% of patients and done in 11%. Recurrence was noted in 43%. Abrupt cessation of steroids was a significant risk factor in recurrence of the disease (P = .046). Recovery was partial in 44% of patients and complete in 47%. Systemic steroids with slow taper has satisfactory outcomes in orbital myositis. Patients refractory to treatment ideally should undergo biopsy and begin taking steroid-sparing agents. Once the disease is in remission, residual disease can be surgically treated for better functional outcome. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].

Evaluation of the Differences in Parameters Obtained from the Computed Tomography Images of the Eyeball and the Structures in the Orbit by Age and Gender

Objective: The aim of this study is to show the variation of eyeball and orbital structures according to different age groups and gender. Methods: The study was carried out on 4 age groups over 30-40, 41-50, 51-60, 61. The parameters were, the angle between the optic nerve and axis of eyeball (A-Cr2AA), the length of the medial rectus muscle (MRML) and the length of the lateral rectus muscle (LRML) up to the Zinn ring, the thickness of the lens (LT),), the length of the optic nerve from the Zinn ring (Cr2L), optic nerve thickness (Cr2T), distance between two eyeballs (BOD) and the others. Results: As a result of the study, in the comparison of males in four groups, significant difference was found between the groups in LT, Cr2L, A-Cr2AA, MRML parameters in the right eyeball and Cr2L and LRML parameters in the left eyeball (p

Evaluation of the Normal Measurements of Orbital Structures in Healthy Adult Individuals by Using a Magnetic Resonance Imaging Method

Background: This study aims to determine the normal values of orbital structures according to sex in healthy adults. Methods: Diameters of extraocular muscles, the width of the optic nerve sheath diameter, the length of the inter-zygomatic line, ocular bulb length, and globe position were measured in the T1-weighed MR (magnetic resonance) images in 204 orbits of 102 individuals. Results: The mean values of the diameters of the extraocular muscles in males and females were as follows: medial rectus, 3.96 ± 0.52 and 3.58 ± 0.53 mm; lateral rectus, 3.47 ± 0.61 and 3.15 ± 0.48 mm; inferior rectus, 4.47 ± 0.53 and 4.07 ± 0.48 mm; superior rectus, 4.44 ± 0.64 and 4.01 ± 0.56 mm; and superior oblique, 3.68 ± 0.49 and 3.45 ± 0.44 mm. The length of the interzygomatic line in males and females were 102.68 ± 3.89 and 96.95 ± 3.4 mm, the ocular bulb length was 23.33 ± 1.32 and 22.83 ± 1.1 mm, the globe position was 7.66 ± 1.33 and 7.3 ± 1.39 mm, and the width of the optic nerve sheath diameter was 4.65 ± 0.62 and 4.28 ± 0.51 mm, respectively. All measurements were significantly greater for males than for females (p &lt; 0.05). Conclusions: We believe that a practical and quantitative method will be provided by this study for the diagnosis and determination of the normative values of orbital structures.

Acute Acquired Comitant Esotropia

Acute acquired comitant esotropia (AACE) is an infrequent presentation of esotropia, characterized by sudden onset eye misalignment and diplopia. The purpose of this article is to review four cases of children diagnosed with AACE. We present 4 cases (children 610 years) of AACE. All of them suddenly developed diplopia and esotropia, with largeangle. After complete ophthalmological and neurological examinations in three cases out of four, strabismus surgery was conducted. In one case heterogenous neoplasm was detected and sent to an oncologist and neurosurgeon for evaluation and morphological verification. Bilateral medial rectus recession in two cases and unilateral recession of the medial rectus and resection of the lateral rectus in one case were performed. After strabismus surgery fully recovered binocular vision and was no longer noticeable diplopia. Neurological examinations and neuroimaging should be performed to exclude any potential intracranial disease. Surgery should be taken into consideration 6 months after the onset of the esotropia, if the deviation is stable. Strabismus surgery of AACE has good motor and sensory results and can successfully restore good binocular function The excessive use of smartphones may be associated with developing and increasing AACE.

The Use of Botulinum Toxin to Treat Infantile Esotropia

Injection of botulinum toxin type A into both rectus muscles is an alternative to surgery and has given good results in children with infantile esotropia. Reducing the angle of deviation can help restore binocular vision, which in turn will promote motor fusion and allow better control of the strabismus and may even lead to eventual healing. We report the result after 6 months of injection of botulinum toxin in the medial rectus in 6 children with infantile esotropia.

Medial rectus re-advancement: more bang for your buck?

ABSTRACT Introduction: Although there are guidance tables in the literature on surgical dosage for primary medial rectus resection-lateral rectus recession surgery, there is a lack of consensus on the surgical gains in medial rectus re-advancement (MRR) for the management of consecutive exotropia. We compared the surgical outcomes of primary medial rectus resection-lateral recession (RR) surgery, to MRR in patients with consecutive exotropia. Methods: Retrospective, electronic note review of consecutive patients undergoing primary RR surgery for basic exotropia (RR group), convergence insufficiency-type exotropia, and divergence excess, and consecutive patients undergoing MRR with or without lateral rectus recession (MRR group) for consecutive exotropia in a teaching university hospital. Results: There were 84 patients in the RR group and 27 patients in the MRR group. The median age in the RR group was 25.50 years (range 4–79) and 45 years (18–87) in the MRR group (p = .002). Median follow-up was 7 months (3–43) in the RR group and 1 month (1–12) in the MRR group. Post-operatively, there was a median exotropia reduction of 27.00 prism diopters (PD) (range +5, –65; p < .0001) for near, and 27.00 PD (+10, –51; p < .0001) for distance in the RR group. In the MRR group, the median exotropia reduction was 34.50 PD (2, –67; p < .0001) for near and 33.00 PD (1, –67; p < .0001) for distance. There was a greater reduction in the exotropia in the MRR group compared to the RR group for distance (p = .047), but this did not meet statistical significance for near (p = 0.10). The median dose–effect relationship (PD/millimeter) was higher in the MRR group both for near deviation (2.90 vs 2.15, p = .0073) and for distance deviation (2.91 vs 2.15, =0.0041). Conclusion: Based on our study cohort, medial rectus re-advancement appears to have a greater dose-effect in reducing the distance angle of deviation for both near and distance compared to primary recess-resect surgery. Further prospective longitudinal studies would shed further light on the dose–effect relationship over time.

Inferior Rectus Muscle Thermal Injury Following Transconjunctival Blepharoplasty Using Carbon Dioxide Laser.

A 56-year-old woman was referred to the authors' hospital after the removal of the lower eyelid fat through a transconjunctival approach using a carbon dioxide laser. The patient was noted to have vertical diplopia in the primary position, with worsening diplopia on downgaze. Detachment of the right inferior rectus (IR) muscle from its insertion point was observed during exploratory surgery. The thermally damaged IR muscle fibers were attached to a location posterior to the original insertion point. At 6 months postoperatively, 8 prism diopters of right hypertropia in the primary position and a -3 degrees limitation on downgaze were still present. The patient underwent the vertical transposition of the lateral and medial rectus muscles to the IR muscle. After strabismus surgery, orthotropia was observed with no vertical diplopia in the primary gaze, but ocular motility limitation on the downgaze has permanently remained.

Prospective Comparison of FOCUS MUSE and Single-Shot Echo-Planar Imaging for Diffusion-Weighted Imaging in Evaluating Thyroid-Associated Ophthalmopathy.

To prospectively compare single-shot (SS) echo-planar imaging (EPI) and field-of-view optimized and constrained undistorted single-shot multiplexed sensitivity-encoding (FOCUS MUSE) for diffusion-weighted imaging (DWI) in evaluating thyroid-associated ophthalmopathy (TAO). SS EPI and FOCUS MUSE DWIs were obtained from 39 patients with TAO (18 male; mean ± standard deviation: 48.3 ± 13.3 years) and 26 healthy controls (9 male; mean ± standard deviation: 43.0 ± 18.5 years). Two radiologists scored the visual image quality using a 4-point Likert scale. The image quality score, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) of extraocular muscles (EOMs) were compared between the two DWIs. Differences in the ADC of EOMs were also evaluated. The performance of discriminating active from inactive TAO was assessed using receiver operating characteristic curves. The correlation between ADC and clinical activity score (CAS) was analyzed using Spearman correlation. Compared with SS EPI DWI, FOCUS MUSE DWI demonstrated significantly higher image quality scores (P < 0.001), a higher SNR and CNR on the lateral rectus muscle (LRM) and medial rectus muscle (MRM) (P < 0.05), and a non-significant difference in the ADC of the LRM and MRM. Active TAO showed higher ADC than inactive TAO and healthy controls with both SS EPI and FOCUS MUSE DWIs (P < 0.001). Inactive TAO and healthy controls did not show a significant ADC difference with both DWIs. Compared with SS EPI DWI, FOCUS MUSE DWI demonstrated better discrimination of active from inactive TAO (AUC: 0.925 vs. 0.779; P = 0.007). The ADC was significantly correlated with CAS in SS EPI DWI (r = 0.391, P < 0.001) and FOCUS MUSE DWI (r = 0.645, P < 0.001). FOCUS MUSE DWI provides better images for evaluating EOMs and better performance in diagnosing active TAO than SS EPI DWI. The application of FOCUS MUSE will facilitate the DWI evaluation of TAO.

A rare case of Parry-Romberg syndrome with restrictive strabismus

Parry-Romberg syndrome is a rare disease characterized by slowly progressive atrophy affecting facial subcutaneous tissues, muscles, osteocartilaginous structures, and possible cerebral involvement. Though bilateral cases have been described, diagnosis is often possible because of the characteristic hemifacial atrophy and resulting facial asymmetry at later stages of the disease. We report a 28-year-old woman with diplopia for the past 3 months with history of gradual loss of subcutaneous fat in the right side of her body. She had severe restriction of adduction of right eye. Multidetector computed tomography scan of the orbit revealed a reduced bulk of the right medial rectus muscle.

Case report on interesting cases of congenital ocular motor apraxia

Congenital ocular motor apraxia (COMA) is an uncommon disorder of ocular motility characterized by inability to initiate voluntary horizontal saccades with associated head thrusts during horizontal fixation shifts. In addition, when ocular movements typical of COMA are observed, detailed systemic and neurologic examination should be performed to rule out any associated congenital neurologic or metabolic disorder. We report two cases of COMA, a 14-year-old male with diminution of vision, esotropia, and his face turned to the right without any systemic disease, and a 9-year-old male with esotropia, no face turn, acute lymphocytic leukemia, and isolated complete agenesis of the corpus callosum. Both cases had abnormal saccadic initiation for horizontal gaze with head thrusts to take fixation. Both cases underwent Medial rectus (MR) recession, which improved face turn and strabismus, respectively.

Efficacy of Nasal Septal Complex in the Endoscopic Reconstruction of Medial Orbital Wall.

The aim of this study is to investigate the efficacy of nasal septal complex reconstructing the medial orbital wall under some specific circumstances. The authors performed a study that included 10 patients who underwent isolated medial orbital wall fracture (blow-out fracture). All the reconstruction surgery of the patient included in this study fixed defect of medial orbital wall using autologous nasal septal complex (composed of nasal septal cartilage and perpendicular plate of ethmoid). The authors observed postoperative improvements of diplopia or ocular motility disorders of the affected orbit. The surgeries had gained satisfactory results, and without severe postoperative complications. After long-term follow-up, postoperative CT indicated the implant-covered defect of medial orbital wall, and there's no incarceration of the medial rectus. Meanwhile, the authors found there is no crack in the implant, and the surgery using nasal septal complex achieved premorbid orbital form. Autologous nasal septal complex provides a better complement to endoscopic reconstruction of medial orbital wall; this strategy allows nasal septum to reconstruct isolated medial orbital wall defects of various degrees, such as nasal septum fracture and dysplasia of perpendicular plate of ethmoid.

Botulinum toxin-A in acute acquired comitant esotropia during COVID pandemic in children and young adolescents

Abstract Purpose: To study the effectiveness of botulinum toxin A (BTX-A) in the treatment of patients with acute acquired comitant esotropia (AACE) due to excessive use of mobile and laptops in the COVID era in the pediatric population and adolescents. Methods: This was a retrospective, interventional study of pediatric patients and young adults who presented with AACE and received unilateral or bilateral BTX-A. All the patients complained of binocular diplopia and sudden onset of esotropia with a history of mobile or laptop usage during the COVID era (2020–2023). Twenty-seven patients with acute-onset esotropia in 3 years (2020–2023) were included. All patients were administered 2.5–7.5 units of BTX-A (Botox, Allergan, India) into the unilateral or bilateral medial rectus muscle of the deviating eye under short general anesthesia or local anesthesia. The main outcome measures were pre- and post-injection angle of deviation, pre- and post-injection stereopsis, final level of stereopsis achieved, recurrence, and whether strabismus surgery was later required. Results: The mean age of patients was 12.85 ± 7.15 years (range: 4–25 years). The mean dosage of Botox was 6 U (2.5–7.5 U). The mean follow-up was 6 months (6 months–2 years). The mean preoperative angle of deviation (AOD) was 41.11 ± 10.9 prism diopters (PD) for distance and 41.67 ± 10.9 PD for near. The maximum effect of BTX-A was seen at 1 month; post-injection AOD was 13.65 ± 14.7 PD for distance and 14.87 ± 15.8 PD for near (P &lt; 0.001). Over half of the patients achieved optimal outcomes, with improvements in stereopsis and sensory fusion. Early intervention (within 3 months of symptom onset) significantly correlated with treatment success. Conclusion: While BTX-A therapy for acute-onset esotropia demonstrates efficacy, patient-specific considerations are essential. This study highlights the evolving nature in the digital age and early administration of BTX-A along with close follow-up to monitor residual and recurrence of esotropia. The surgical intervention can increase the final success rate.

Efficacy of Fat and Perifascial Areolar Tissue Graft in Refractory Esotropia: A Case Report

Purpose: This case report presents a novel approach for the management of refractory esotropia using adhesiolysis and fat and perifascial areolar tissue (PAT) transplantation.Case summary: A 62-year-old male presented with left eye strabismus fixus following iatrogenic medial rectus (MR) muscle injury and medial orbital wall fracture during endoscopic sinus surgery. One month later, he underwent MR laceration repair and orbital wall reconstruction. Despite three subsequent interventions for exotropia and its subsequent conversion to esotropia, the left eye esodeviation progressively worsened, culminating in strabismus fixus. Initial examination revealed significant left eye esotropia with fixed gaze and 5-mm enophthalmos. Surgery included implant removal, adhesiolysis between the eyeball and surrounding tissues, scar and MR recession, and placement of a fat and PAT graft on the medial aspect of the eyeball to prevent postoperative re-adhesion. Three years of follow-up demonstrated sustained orthophoria in primary gaze with improved extraocular muscle function and enophthalmos.Conclusions: Fat and PAT graft has potential in oculoplastics for preventing re-adhesion and augmenting orbital volume in patients with refractory restrictive strabismus due to multiple surgeries.

Satellite cell distribution in the medial rectus muscle in cadavers

Background: This study aimed to elucidate the potential usefulness of the medial rectus muscle of cadavers for research on satellite cells.Methods: Twenty-four medial rectus muscles were obtained from 12 cadavers. The control group included six medial rectus muscles from three live adults without brain activity. The muscle fiber diameter and distribution of satellite cells were measured and compared. Immunohistochemistry for myosin heavy chain and the transcription factor PAX7 was performed, and the distributions of myocytes and satellite cells were evaluated.Results: The average muscle fiber diameter was 142.18±36.49 μm in the cadaver group and 149.34±15.26 μm in the control group, and there was no significant difference between the two groups (p=0.38). The ratio of PAX7(+) cells to the number of muscle fibers was 0.056±0.015 in the control group and 0.006±0.006 in the cadaver group, reflecting a significant difference (p&lt;0.05).Conclusions: The medial rectus muscles of cadavers can be helpful in studying anatomical morphology; however, their usefulness in muscle satellite cell research appears to be limited.