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Jeong-min Hwang - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Facial Asymmetry in Congenital Superior Oblique Palsy according to Trochlear Nerve Absence.
Journal of ophthalmology, 2020Co-Authors: Hee Kyung Yang, Su-min Jung, Taeg Keun Whangbo, Jeong-min HwangAbstract:Background/Aims. Facial asymmetry is affected by various developmental factors, and congenital superior oblique palsy (SOP) is one of the most common causes of asymmetric development of the face. The presence of facial symmetry is usually assessed subjectively, which varies with the examiner. We aimed to objectively assess facial asymmetry in patients with unilateral congenital SOP according to the presence or absence of the Trochlear Nerve on high-resolution magnetic resonance imaging (MRI). Methods. A total of 287 consecutive patients diagnosed with congenital SOP and 82 control subjects were included. Congenital SOP patients were grouped according to the presence (present group) or absence (absent group) of the Trochlear Nerve using thin-section high-resolution MRI of cranial Nerves. We developed a computer-aided detection (CAD) system that could automatically analyze objective indices of facial asymmetry using frontal face photographs. Results. Of the 287 patients with congenital SOP, 60% of patients had ipsilateral Trochlear Nerve absence and superior oblique muscle (SO) hypoplasia (absent group), while the remaining 40% had a normal SO and Trochlear Nerve (present group). All but one objective indices related to facial asymmetry were significantly different between congenital SOP patients and controls (all ). Among these features, the angle of nose deviation was significantly larger in the absent group compared to the present group ( ). Conclusion. Objective analysis of facial asymmetry using our novel CAD system was useful for identifying distinct features of congenital SOP. Deviation of the nose was more prominent in congenital SOP patients with Trochlear Nerve absence.
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Ocular Torsion According to Trochlear Nerve Absence in Unilateral Superior Oblique Palsy.
Investigative ophthalmology & visual science, 2017Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:Purpose To investigate the relationship between objective ocular torsion and the presence or absence of the Trochlear Nerve in subjects with unilateral superior oblique palsy (SOP). Methods A total of 159 subjects with congenital and acquired unilateral SOP were reviewed. Eighty-four subjects who had a normal Trochlear Nerve (present group) and 75 subjects without a Trochlear Nerve (absent group) were included. Cyclovertical motility parameters and objective ocular torsion were compared between groups, and factors related to ocular torsion were evaluated. Results The degree of "net" excyclotorsion in the paretic eye was larger in the absent group compared to the present group (P = 0.002). The proportion of net excyclotorsion in the paretic eye was greater in the absent group (11% vs. 37%), while net incyclotorsion was greater in the present group (41% vs. 23%) (P < 0.001). Net excyclotorsion of the paretic eye was associated with absence of the Trochlear Nerve (P < 0.001) and smaller size of the paretic SO (P < 0.001). Net incyclotorsion of the paretic eye was related with a normal Trochlear Nerve (P = 0.005), larger size of the paretic SO (P = 0.002), and greater hypertropia during ipsilateral gaze (P = 0.024). Conclusions The status of the Trochlear Nerve, paretic SO size, and hypertropia during ipsilateral gaze which reflects the tensile strength of the ipsilateral superior rectus, significantly contribute to ocular torsion in unilateral SOP.
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Surgical Outcomes of Inferior Oblique Myectomy in Unilateral Congenital Superior Oblique Palsy with or without Trochlear Nerve
PloS one, 2016Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jeong-min HwangAbstract:Objectives To compare the surgical outcomes of inferior oblique (IO) myectomy in congenital superior oblique palsy (SOP) according to the presence of the Trochlear Nerve identified with high-resolution MRI. Data Extraction Forty-one congenital SOP patients without a Trochlear Nerve (absent group) and 23 patients with a Trochlear Nerve (present group) who underwent IO myectomy as the primary surgical treatment were retrospectively reviewed. “Motor success” was defined as postoperative ipsilateral hypertropia ≤ 4 prism diopter (PD). “Head tilt improvement” was regarded as postoperative angle of head tilt < 5 degrees (°). Success rates for motor alignment and head tilt improvement, cumulative probabilities of success, and factors influencing surgical responses were evaluated. Results The cumulative probabilities of motor success at 2 years after IO myectomy were 92% in patients with a Trochlear Nerve and 86% in patients without a Trochlear Nerve (P = 0.138). The cumulative probabilities of undercorrection and recurrence of hypertropia after 2 years were 0% in the present group versus 21% in the absent group (P = 0.014). The cumulative probabilities of persistent head tilt after 2 years were 14% in the present group and 20% in the absent group (P = 0.486). A younger age at operation was associated with reduced probabilities of motor success and head tilt improvement (P = 0.009, P = 0.022 respectively). A greater preoperative angle of head tilt was associated with persistent head tilt after surgery (P = 0.038). Conclusions Congenital SOP without a Trochlear Nerve had a higher risk of hypertropia undercorrection after IO myectomy compared to patients with a Trochlear Nerve. A younger age at operation and larger preoperative head tilt was related to poor outcomes.
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Clinical Characteristics of Patients with Congenital Superior Oblique Palsy Compared between Patients with a Trochlear Nerve (Present Group) versus Those without a Trochlear Nerve (Absent Group).
2016Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jeong-min HwangAbstract:Clinical Characteristics of Patients with Congenital Superior Oblique Palsy Compared between Patients with a Trochlear Nerve (Present Group) versus Those without a Trochlear Nerve (Absent Group).
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Morphometry of the Trochlear Nerve and superior oblique muscle volume in congenital superior oblique palsy.
Investigative ophthalmology & visual science, 2014Co-Authors: Dae Seung Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:PURPOSE To infer the pathogenic mechanism of congenital superior oblique palsy (SOP) by evaluating Trochlear Nerve diameter (CN4D) and superior oblique muscle (SO) volume in patients with congenital SOP. METHODS The medical records of 125 patients diagnosed with unilateral congenital SOP and 34 age-matched healthy controls were reviewed retrospectively. Using thin-section high-resolution magnetic resonance imaging, we evaluated the presence of the Trochlear Nerve, CN4D, SO volume, and their relationship. RESULTS Of the 125 patients with congenital SOP, 87 showed absence of the Trochlear Nerve (n = 87, 70%, absent group) and 38 showed bilateral presence of the Trochlear Nerve (n = 38, 30%, present group). The nonparetic side CN4D was smaller than controls in the absent group (P = 0.001), and larger than controls in the present group (P = 0.001). Trochlear Nerve diameter positively correlated with SO volume in controls (P = 0.014, R(2) = 0.174) and in the nonparetic sides of congenital SOP (present group P = 0.023, R(2) = 0.135; absent group, P = 0.008, R(2) = 0.079). The paretic side SO volume did not show a linear correlation between CN4D and SO volume in the present group (P = 0.243). CONCLUSIONS In congenital SOP patients without a Trochlear Nerve, the nonparetic side CN4D was also reduced in contrast to those with a Trochlear Nerve. The relatively weaker relationship of CN4D and nonparetic side SO volume in the absent group than that of the present group suggests different pathogenic mechanisms underlying these two entities of congenital SOP.
Kevin H. Ruggles - One of the best experts on this subject based on the ideXlab platform.
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Transient Trochlear Nerve palsy following anterior temporal lobectomy for epilepsy
Neurology, 1995Co-Authors: Daniel M. Jacobson, John J. Warner, Kevin H. RugglesAbstract:Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery.We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear Nerve palsy--not oculomotor Nerve palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the Trochlear Nerve is a plausible mechanism that would explain this complication. NEUROLOGY 1995;45: 1465-1468
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Transient Trochlear Nerve palsy following anterior temporal lobectomy for epilepsy
Neurology, 1995Co-Authors: Daniel M. Jacobson, John J. Warner, Kevin H. RugglesAbstract:Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery. We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear Nerve palsy--not oculomotor Nerve palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the Trochlear Nerve is a plausible mechanism that would explain this complication.
Daniel M. Jacobson - One of the best experts on this subject based on the ideXlab platform.
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Isolated Trochlear Nerve palsy in patients with multiple sclerosis
Neurology, 1999Co-Authors: Daniel M. Jacobson, Mark L. Moster, E. R. Eggenberger, Steven Galetta, Grant T. LiuAbstract:The authors describe five patients with Trochlear Nerve palsy and MS to characterize this rare association. In two patients, Trochlear Nerve palsy was the initial clinical manifestation of MS. In the other three patients, this sign occurred after previous neurologic events. MRI did not identify a lesion of the fourth Nerve nucleus or fascicle. Ophthalmoplegia resolved within 2 months in four of the five patients. A reason this association is rare is that the fascicular course of the Trochlear Nerve is exposed to little myelin.
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Transient Trochlear Nerve palsy following anterior temporal lobectomy for epilepsy
Neurology, 1995Co-Authors: Daniel M. Jacobson, John J. Warner, Kevin H. RugglesAbstract:Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery.We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear Nerve palsy--not oculomotor Nerve palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the Trochlear Nerve is a plausible mechanism that would explain this complication. NEUROLOGY 1995;45: 1465-1468
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Transient Trochlear Nerve palsy following anterior temporal lobectomy for epilepsy
Neurology, 1995Co-Authors: Daniel M. Jacobson, John J. Warner, Kevin H. RugglesAbstract:Three of 22 patients (14%) who underwent anterior temporal lobectomy for treatment of medically intractable epilepsy at our institution from July 1987 through July 1993 experienced diplopia immediately after surgery. We found ipsilateral paresis of the superior oblique muscle in all three patients. Their ophthalmoplegia resolved completely within 14 weeks. We did not observe any new structural or ischemic changes on postoperative MRIs to account for their deficits. Trochlear Nerve palsy--not oculomotor Nerve palsy, as is reported in most reference texts--is a relatively common cause of transient diplopia following temporal lobectomy. Indirect (ie, traction) injury of the Trochlear Nerve is a plausible mechanism that would explain this complication.
Hee Kyung Yang - One of the best experts on this subject based on the ideXlab platform.
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Characteristics of Facial Asymmetry in Congenital Superior Oblique Palsy according to Trochlear Nerve Absence.
Journal of ophthalmology, 2020Co-Authors: Hee Kyung Yang, Su-min Jung, Taeg Keun Whangbo, Jeong-min HwangAbstract:Background/Aims. Facial asymmetry is affected by various developmental factors, and congenital superior oblique palsy (SOP) is one of the most common causes of asymmetric development of the face. The presence of facial symmetry is usually assessed subjectively, which varies with the examiner. We aimed to objectively assess facial asymmetry in patients with unilateral congenital SOP according to the presence or absence of the Trochlear Nerve on high-resolution magnetic resonance imaging (MRI). Methods. A total of 287 consecutive patients diagnosed with congenital SOP and 82 control subjects were included. Congenital SOP patients were grouped according to the presence (present group) or absence (absent group) of the Trochlear Nerve using thin-section high-resolution MRI of cranial Nerves. We developed a computer-aided detection (CAD) system that could automatically analyze objective indices of facial asymmetry using frontal face photographs. Results. Of the 287 patients with congenital SOP, 60% of patients had ipsilateral Trochlear Nerve absence and superior oblique muscle (SO) hypoplasia (absent group), while the remaining 40% had a normal SO and Trochlear Nerve (present group). All but one objective indices related to facial asymmetry were significantly different between congenital SOP patients and controls (all ). Among these features, the angle of nose deviation was significantly larger in the absent group compared to the present group ( ). Conclusion. Objective analysis of facial asymmetry using our novel CAD system was useful for identifying distinct features of congenital SOP. Deviation of the nose was more prominent in congenital SOP patients with Trochlear Nerve absence.
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Ocular Torsion According to Trochlear Nerve Absence in Unilateral Superior Oblique Palsy.
Investigative ophthalmology & visual science, 2017Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:Purpose To investigate the relationship between objective ocular torsion and the presence or absence of the Trochlear Nerve in subjects with unilateral superior oblique palsy (SOP). Methods A total of 159 subjects with congenital and acquired unilateral SOP were reviewed. Eighty-four subjects who had a normal Trochlear Nerve (present group) and 75 subjects without a Trochlear Nerve (absent group) were included. Cyclovertical motility parameters and objective ocular torsion were compared between groups, and factors related to ocular torsion were evaluated. Results The degree of "net" excyclotorsion in the paretic eye was larger in the absent group compared to the present group (P = 0.002). The proportion of net excyclotorsion in the paretic eye was greater in the absent group (11% vs. 37%), while net incyclotorsion was greater in the present group (41% vs. 23%) (P < 0.001). Net excyclotorsion of the paretic eye was associated with absence of the Trochlear Nerve (P < 0.001) and smaller size of the paretic SO (P < 0.001). Net incyclotorsion of the paretic eye was related with a normal Trochlear Nerve (P = 0.005), larger size of the paretic SO (P = 0.002), and greater hypertropia during ipsilateral gaze (P = 0.024). Conclusions The status of the Trochlear Nerve, paretic SO size, and hypertropia during ipsilateral gaze which reflects the tensile strength of the ipsilateral superior rectus, significantly contribute to ocular torsion in unilateral SOP.
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Surgical Outcomes of Inferior Oblique Myectomy in Unilateral Congenital Superior Oblique Palsy with or without Trochlear Nerve
PloS one, 2016Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jeong-min HwangAbstract:Objectives To compare the surgical outcomes of inferior oblique (IO) myectomy in congenital superior oblique palsy (SOP) according to the presence of the Trochlear Nerve identified with high-resolution MRI. Data Extraction Forty-one congenital SOP patients without a Trochlear Nerve (absent group) and 23 patients with a Trochlear Nerve (present group) who underwent IO myectomy as the primary surgical treatment were retrospectively reviewed. “Motor success” was defined as postoperative ipsilateral hypertropia ≤ 4 prism diopter (PD). “Head tilt improvement” was regarded as postoperative angle of head tilt < 5 degrees (°). Success rates for motor alignment and head tilt improvement, cumulative probabilities of success, and factors influencing surgical responses were evaluated. Results The cumulative probabilities of motor success at 2 years after IO myectomy were 92% in patients with a Trochlear Nerve and 86% in patients without a Trochlear Nerve (P = 0.138). The cumulative probabilities of undercorrection and recurrence of hypertropia after 2 years were 0% in the present group versus 21% in the absent group (P = 0.014). The cumulative probabilities of persistent head tilt after 2 years were 14% in the present group and 20% in the absent group (P = 0.486). A younger age at operation was associated with reduced probabilities of motor success and head tilt improvement (P = 0.009, P = 0.022 respectively). A greater preoperative angle of head tilt was associated with persistent head tilt after surgery (P = 0.038). Conclusions Congenital SOP without a Trochlear Nerve had a higher risk of hypertropia undercorrection after IO myectomy compared to patients with a Trochlear Nerve. A younger age at operation and larger preoperative head tilt was related to poor outcomes.
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Clinical Characteristics of Patients with Congenital Superior Oblique Palsy Compared between Patients with a Trochlear Nerve (Present Group) versus Those without a Trochlear Nerve (Absent Group).
2016Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jeong-min HwangAbstract:Clinical Characteristics of Patients with Congenital Superior Oblique Palsy Compared between Patients with a Trochlear Nerve (Present Group) versus Those without a Trochlear Nerve (Absent Group).
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Morphometry of the Trochlear Nerve and superior oblique muscle volume in congenital superior oblique palsy.
Investigative ophthalmology & visual science, 2014Co-Authors: Dae Seung Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:PURPOSE To infer the pathogenic mechanism of congenital superior oblique palsy (SOP) by evaluating Trochlear Nerve diameter (CN4D) and superior oblique muscle (SO) volume in patients with congenital SOP. METHODS The medical records of 125 patients diagnosed with unilateral congenital SOP and 34 age-matched healthy controls were reviewed retrospectively. Using thin-section high-resolution magnetic resonance imaging, we evaluated the presence of the Trochlear Nerve, CN4D, SO volume, and their relationship. RESULTS Of the 125 patients with congenital SOP, 87 showed absence of the Trochlear Nerve (n = 87, 70%, absent group) and 38 showed bilateral presence of the Trochlear Nerve (n = 38, 30%, present group). The nonparetic side CN4D was smaller than controls in the absent group (P = 0.001), and larger than controls in the present group (P = 0.001). Trochlear Nerve diameter positively correlated with SO volume in controls (P = 0.014, R(2) = 0.174) and in the nonparetic sides of congenital SOP (present group P = 0.023, R(2) = 0.135; absent group, P = 0.008, R(2) = 0.079). The paretic side SO volume did not show a linear correlation between CN4D and SO volume in the present group (P = 0.243). CONCLUSIONS In congenital SOP patients without a Trochlear Nerve, the nonparetic side CN4D was also reduced in contrast to those with a Trochlear Nerve. The relatively weaker relationship of CN4D and nonparetic side SO volume in the absent group than that of the present group suggests different pathogenic mechanisms underlying these two entities of congenital SOP.
Jae Hyoung Kim - One of the best experts on this subject based on the ideXlab platform.
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Ocular Torsion According to Trochlear Nerve Absence in Unilateral Superior Oblique Palsy.
Investigative ophthalmology & visual science, 2017Co-Authors: Ji Eun Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:Purpose To investigate the relationship between objective ocular torsion and the presence or absence of the Trochlear Nerve in subjects with unilateral superior oblique palsy (SOP). Methods A total of 159 subjects with congenital and acquired unilateral SOP were reviewed. Eighty-four subjects who had a normal Trochlear Nerve (present group) and 75 subjects without a Trochlear Nerve (absent group) were included. Cyclovertical motility parameters and objective ocular torsion were compared between groups, and factors related to ocular torsion were evaluated. Results The degree of "net" excyclotorsion in the paretic eye was larger in the absent group compared to the present group (P = 0.002). The proportion of net excyclotorsion in the paretic eye was greater in the absent group (11% vs. 37%), while net incyclotorsion was greater in the present group (41% vs. 23%) (P < 0.001). Net excyclotorsion of the paretic eye was associated with absence of the Trochlear Nerve (P < 0.001) and smaller size of the paretic SO (P < 0.001). Net incyclotorsion of the paretic eye was related with a normal Trochlear Nerve (P = 0.005), larger size of the paretic SO (P = 0.002), and greater hypertropia during ipsilateral gaze (P = 0.024). Conclusions The status of the Trochlear Nerve, paretic SO size, and hypertropia during ipsilateral gaze which reflects the tensile strength of the ipsilateral superior rectus, significantly contribute to ocular torsion in unilateral SOP.
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Morphometry of the Trochlear Nerve and superior oblique muscle volume in congenital superior oblique palsy.
Investigative ophthalmology & visual science, 2014Co-Authors: Dae Seung Lee, Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:PURPOSE To infer the pathogenic mechanism of congenital superior oblique palsy (SOP) by evaluating Trochlear Nerve diameter (CN4D) and superior oblique muscle (SO) volume in patients with congenital SOP. METHODS The medical records of 125 patients diagnosed with unilateral congenital SOP and 34 age-matched healthy controls were reviewed retrospectively. Using thin-section high-resolution magnetic resonance imaging, we evaluated the presence of the Trochlear Nerve, CN4D, SO volume, and their relationship. RESULTS Of the 125 patients with congenital SOP, 87 showed absence of the Trochlear Nerve (n = 87, 70%, absent group) and 38 showed bilateral presence of the Trochlear Nerve (n = 38, 30%, present group). The nonparetic side CN4D was smaller than controls in the absent group (P = 0.001), and larger than controls in the present group (P = 0.001). Trochlear Nerve diameter positively correlated with SO volume in controls (P = 0.014, R(2) = 0.174) and in the nonparetic sides of congenital SOP (present group P = 0.023, R(2) = 0.135; absent group, P = 0.008, R(2) = 0.079). The paretic side SO volume did not show a linear correlation between CN4D and SO volume in the present group (P = 0.243). CONCLUSIONS In congenital SOP patients without a Trochlear Nerve, the nonparetic side CN4D was also reduced in contrast to those with a Trochlear Nerve. The relatively weaker relationship of CN4D and nonparetic side SO volume in the absent group than that of the present group suggests different pathogenic mechanisms underlying these two entities of congenital SOP.
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Congenital superior oblique palsy and Trochlear Nerve absence: a clinical and radiological study.
Ophthalmology, 2011Co-Authors: Hee Kyung Yang, Jae Hyoung Kim, Jeong-min HwangAbstract:Objective To evaluate patients with congenital superior oblique palsy (SOP) by classifying them according to their magnetic resonance imaging (MRI) findings and cross-comparing the clinical characteristics of each group. Design Retrospective, observational study. Participants Ninety-seven consecutive patients diagnosed with congenital SOP. Methods Medical records of patients who demonstrated typical signs of congenital SOP were reviewed. The presence or absence of the Trochlear Nerve was visualized with thin-section high-resolution MRI of the cranial Nerves. Main Outcome Measures Presence of the Trochlear Nerve and superior oblique (SO) muscle hypoplasia on MRI, age at the onset of symptoms or signs, ocular motility examination results, objective ocular torsion, and surgical outcomes. Results Of the 97 patients with congenital SOP, 73% of patients were identified with an ipsilateral absent Trochlear Nerve and variable degree of SO muscle hypoplasia (absent group), whereas the remaining 27% had a normal Trochlear Nerve and normal symmetric SO muscle (present group). Patients with an absent Trochlear Nerve showed more frequent head tilt ( P = 0.030) that was manifest at an earlier onset before 1 year of age ( P P = 0.008) and more frequently were associated with dissociated vertical deviation (DVD; P = 0.025). Conclusions Congenital SOP patients without a Trochlear Nerve had a hypoplastic SO muscle and frequently manifested head tilt at an earlier age, whereas patients with a normal Trochlear Nerve showed prominent overelevation in adduction and frequent DVD. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Absence of the Trochlear Nerve in Patients with Superior Oblique Hypoplasia
Ophthalmology, 2010Co-Authors: Jae Hyoung Kim, Jeong-min HwangAbstract:Objective Congenital cranial dysinnervation disorders (CCDDs) are developmental abnormalities involving the hypoplasia or aplasia of the cranial Nerves with muscle dysinnervation. This study aimed to determine if congenital superior oblique palsy with superior oblique hypoplasia also can be classified as a CCDD. Design Observational case series. Participants Ten patients with superior oblique hypoplasia. Methods Ophthalmologic examination and thin-section magnetic resonance imaging (MRI) at the brainstem level as well as across the orbit were performed in 10 patients with superior oblique hypoplasia. To confirm the accuracy of the procedure, the results obtained were compared with those of a control group comprising 12 children by using the same technique. Main Outcome Measures Examination of ductions and versions, 3-step test, angle of deviation, and presence of the Trochlear Nerve and superior oblique hypoplasia on MRI. Results Trochlear Nerve was absent on the affected side in 10 patients with confirmed hypoplastic superior oblique muscles. The Trochlear Nerves as well as normal-sized superior oblique muscles were observed in 24 (100%) of 24 eyes screened as controls. Conclusions Congenital superior oblique palsy with superior oblique hypoplasia also can be classified as a CCDD by the MRI documentation of congenital aplasia of the Trochlear Nerve. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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High-Resolution 3D MR Imaging of the Trochlear Nerve
AJNR. American journal of neuroradiology, 2010Co-Authors: Byung Se Choi, Jae Hyoung Kim, C. Jung, J. M. HwangAbstract:BACKGROUND AND PURPOSE: The cisternal segment of the Trochlear Nerve is difficult to identify reliably by routine MR imaging. We investigated the visibility and anatomic features of the Trochlear Nerve by using high-resolution 3D-bTFE imaging in healthy subjects. MATERIALS AND METHODS: This study was conducted with 32 healthy subjects without ocular movement disorders. For us to visualize the cisternal segment of the Trochlear Nerve, all subjects underwent 3D-bTFE imaging at 3T with 2 different resolutions: conventional resolution (voxel size, 0.67 × 0.45 × 1.4 mm) and high resolution (voxel size, 0.3 × 0.3 × 0.25 mm). Visibility of the Trochlear Nerve was graded with the use of a qualitative scale of certainty as follows: definite, probable, and indeterminate. The diameter of the Trochlear Nerve was measured. RESULTS: On conventional-resolution images, the visibility of the Trochlear Nerve was definite in 3 Nerves, probable in 12 Nerves, and indeterminate in 49 Nerves. On high-resolution images, visibility was definite in 63 Nerves and probable in 1 Nerve. The mean diameter of the Trochlear Nerve was 0.54 mm (range, 0.35–0.96 mm). CONCLUSIONS: The Trochlear Nerve was visualized 100% of the time on high-resolution imaging with a voxel smaller than the Nerve diameter. High-resolution imaging should have an important role in investigating the pathogenic mechanism of neuropathic strabismus, such as congenital superior oblique palsy.
