Trochlear nerve palsy is a common cause of double vision, particularly vertical diplopia. Surgery might be necessary if the condition does not improve independently. The success of the surgery can vary based on the method employed, and clear factors to predict its effectiveness are not evident. This study evaluates surgical techniques, success rates, and prognostic factors for trochlear nerve palsy at a tertiary hospital. A retrospective chart review was conducted on patients undergoing strabismus surgery for trochlear nerve palsy at Phramongkutklao Hospital between April 2012 and July 2024. Collected data included demographics, visual acuity, stereopsis, etiology, preoperative angles, surgical methods, and postoperative outcomes. A literature review regarding surgical success and prognostic factors was also conducted. Seventy-two cases were included, with 79.2% involving decompensated congenital trochlear nerve palsy. The overall surgical success rate was 76.39%, and inferior oblique myectomy was the most common and effective procedure (44.4% of cases). Based on multivariate logistic regression analysis, a preoperative hypertropia of ≤15 prism diopters was the significant factor for predicting successful outcomes in this study (OR 5.13, 95% CI 1.19-22.18). Inferior oblique muscle surgery effectively addresses small-angle deviations in trochlear nerve palsy. A <15 prism diopters vertical deviation strongly predicted positive surgical outcomes in this study. Further studies are needed to compare surgical techniques and explore additional prognostic factors to optimize long-term outcomes and improve patient care. Trochlear nerve palsy can lead to double vision, and surgery is required if there is no spontaneous improvement. The success of surgical procedures varies based on technique, and there are limited known predictors for which patients may achieve optimal results. When the condition does not resolve independently, surgery is necessary to rectify eye misalignment. This study explored various surgical methods, their success rates, and the factors affecting favorable outcomes from trochlear nerve palsy surgery. A review of medical records for 72 patients who underwent surgery for trochlear nerve palsy at Phramongkutklao Hospital between 2012 and 2024 showed that congenital causes were the most prevalent, accounting for 79.2% of cases. The findings indicated that 76.39% of the surgeries were successful, with inferior oblique myectomy being the most effective and frequently performed procedure. The primary predictor for a successful surgery was having a preoperative eye misalignment, specifically hypertropia, of ≤15 prism diopters. Notably, inferior oblique surgery successfully addresses small-angle deviations, with preoperative hypertropia remarkably predicting the surgical success. Further studies are necessary to compare surgical methods and explore other factors that may enhance long-term outcomes.

Congenital trochlear nerve palsy is the most common cause of vertical strabismus. The goal of this study was to investigate surgical outcomes after superior oblique tendon plication with or without inferior oblique recession in children and adults with unilateral congenital trochlear nerve palsy. Data and outcomes were collected in patients with a diagnosis of unilateral congenital superior oblique palsy during a retrospective single-center study conducted at the University Hospital of Tours. A reproducible, standard ophthalmological and oculomotor examination was performed pre- and postoperatively at 1 year, including presence or absence of diplopia, vertical and horizontal deviations, and compensatory head posture. Surgical success, defined as an endpoint including absence of diplopia in primary position, absence of head tilt, and vertical deviation at distance fixation<5 prism diopters (PD), was analyzed. A total of fifty-seven patients (median [IQR] age of 11 years [5-42]) were analyzed. Patients experienced a significant reduction in vertical distance and near deviations (p<0.001), compensatory head tilt (p < 0.001), and diplopia after surgery (p < 0.001). Surgical success was higher in adults (17/24, 70.8%) than in children (15/33, 45.5%), although this did not reach statistical significance (p=0.0657). This study suggests that plication of the superior oblique muscle tendon, with or without recession of the inferior oblique muscle, can be effective in treating unilateral congenital trochlear nerve palsy. Further studies are necessary to compare surgical procedures and investigate their efficacy in adults compared to children in the short and long term.

Congenital cranial dysinnervation disorders are a group of diseases caused by abnormal development of cranial nerve nuclei or their axonal connections, resulting in aberrant innervation of the ocular and facial musculature. Its diagnosis could be facilitated by the development of high resolution thin-section magnetic resonance imaging. The purpose of this review is to describe the method to visualize cranial nerves III, IV, and VI and to present the imaging findings of congenital cranial dysinnervation disorders including congenital oculomotor nerve palsy, congenital trochlear nerve palsy, Duane retraction syndrome, Möbius syndrome, congenital fibrosis of the extraocular muscles, synergistic divergence, and synergistic convergence.

Congenital trochlear palsy may manifest with sudden vertical diplopia due to decompensation during the later life, which may bring a diagnostic challenge. Two men with vertical diplopia for several years after age of 50 were referred with persisting or suddenly aggravating diplopia. Findings were consistent with unilateral superior oblique palsy (SOP) in both patients with a contraversive head tilt. Facial asymmetry was suggestive of a congenital cause in a patient. High resolution magnetic resonance image (MRI)s disclosed atrophic superior oblique and absent trochlear nerve in the side of SOP in both patients. Imaging demonstration of superior oblique atrophy and absent trochlear nerve may aid in diagnosis of congenital SOP presenting sudden vertical diplopia during the later life due to delayed decompensation.