Modified inferior oblique anterior transposition for dissociated vertical deviation combined with superior oblique palsy:A case report

BACKGROUND Inferior oblique anterior transposition(IOAT)has emerged as an effective surgery in the management of dissociated vertical deviation(DVD)combined with superior oblique palsy(SOP).Traditional IOAT usually provides satisfactory primary position alignment and simultaneously restricts the superior floating phenomenon.However,it also increases the risk of the anti-elevation syndrome and narrowing of the palpebral fissure in straight-ahead gaze,especially after the unilateral operation.CASE SUMMARY We report the outcomes of the modified unilateral IOAT in two patients with unilateral DVD combined with SOP.The anterior-nasal fibers of the inferior oblique muscle were attached at 9 mm posterior to the corneal limbus along the temporal board of the inferior rectus muscle,the other fibers were attached a further 5 mm temporal to the anterior-nasal fibers.Postoperatively,both hypertropia and floating were improved,and no obvious complications occurred.CONCLUSION In these cases,the modified unilateral IOAT was an effective and safe surgical method for treating DVD with SOP.

Inferior oblique weakening surgery on ocular torsion in congenital superior oblique palsy

AIM: To investigate changes in fundus excyclotorsion after inferior oblique myectomy or myotomy. METHODS: The records of 21 patients undergoing strabismus surgery by a single surgeon between 2009 and 2012 were examined. Only patients who had undergone an inferior oblique myectomy or myotomy,with or without horizontal rectus muscle surgery, were evaluated. Digital fundus photographs were obtained,and the angle formed by a horizontal line passing through the optic disc center and a reference line connecting the foveola and optic disc center was measured. Associated clinical factors examined include age at the time of surgery, presence or absence of a head tilt, degree of preoperative vertical deviation,torsional angle, inferior oblique muscle overaction/superior oblique muscle underaction, and surgery laterality. Whether the procedure was performed alone or in combination with a horizontal rectus muscle surgery was also examined. RESULTS: Mean preoperative torsional angle was12. 0 ± 6. 4 °, which decreased to 6. 9 ± 5. 7 ° after surgery(P 【0.001, paired t-test). Torsional angle also decreased from 15. 1 ± 7. 0 ° to 6. 2 ± 4. 3 ° in the myectomy group(P 【0.001, paired t-test) but there were no significant changes in the myotomy group(P =0.093, Wilcoxon signed rank test). Multivariable linear regression analysis showed that preoperative torsional angle, degree ofinferior oblique overaction, and age at surgery independently and significantly affected postoperative torsional angle.CONCLUSION: Mean torsional angle decreased after inferior oblique myectomy. Degree of preoperative torsional angle, inferior oblique overaction, and age at surgery influence postoperative torsional angle.

Surgical outcomes for unilateral superior oblique palsy in Chinese population: a retrospective study

AIM: To evaluate the outcome after surgery for unilateral superior oblique(SO) palsy in Chinese.METHODS: The medical records of 39 patients that underwent surgery for unilateral SO palsy between January 2003 and December 2012 at Caritas Medical Centre, Hong Kong, were retrospectively reviewed. All surgeries were performed by a single surgeon. Pre-operative assessments for vertical deviation, cyclo-deviation, and Knapp’s classification were obtained to determine the nature and degree of surgical correction.Vertical deviation was measured at 1wk; 1, 6mo and on last follow-up day post-operatively. Cyclo-deviation was measured on last follow-up day post-operatively.RESULTS: During the 10 y period, 39 subjects were recruited. The most common etiology was congenital(94.9%). Knapp’s Type III(66.7%) and Type I(12.8%)classifications were the most common subtypes. To treat SO palsy, the most common surgical procedures were:isolated inferior oblique(IO) anteriorization(41.0%),isolated IO myectomy(10.3%), and isolated IO recession(10.3%). At 3.5 ±2.1y post-operatively, the vertical deviation was significantly reduced(15.1 ±6.2 PD versus0.5±1.4 PD, P 【0.0001) without significant improvement in cyclo-deviation(P =0.5). Initial vertical deviation was correlated with cyclo-torsion(r =0.4, P =0.007). Those with over-correction had greater initial vertical deviation(19.4±7.2 PD versus 13.2±4.3 PD, P =0.003). After a single operation, 84.6% of subjects achieved a vertical deviation within ±3 PD.· CONCLUSION: The majority of subjects achieved corrected vertical deviation after a single surgery although there was no improvement in cyclo-deviation.Those with over-correction of primary position deviation had greater preoperative vertical deviation and it may be related to simultaneous multiple muscle surgery.

Effect of unilateral inferior oblique weakening on fundus torsion in bilateral eyes of children with congenital superior oblique palsy

AIM:To study the change of torsion in both eyes after unilateral inferior oblique(IO)weakening on children with congenital superior oblique palsy(SOP).METHODS:This retrospective study enrolled all patients diagnosed with unilateral congenital superior oblique palsy(UCSOP)accompanied by inferior oblique overaction(IOOA).A total of 120 eyes of 60 patients were divided into group 1(more extorted paretic eye)and group 2(more extorted nonparetic eye).The degree of fundus torsion was evaluated before and 1 mo after the IO weakening procedure.The torsion of the fundus was recorded by measuring the diskfoveal angle(DFA)using fundus photography.RESULTS:Group 1 included 26 cases and group 2 included 34 cases,thus the rate of extorsion was insignificantly higher in the nonparetic eye(P=0.10).The preoperative DFA in the paretic and nonparetic eyes was 13.21±5.95,7.97±4.25 in group 1,and 4.65±3.79,13.16±5.35 in group 2(both P<0.001).The postoperative DFA in the paretic and nonparetic eyes was 8.57±4.87,7.32±4.27 in group 1(P=0.24),and 3.85±6.00 and 9.94±5.45 in group 2(P<0.001).The amount of postoperative reduction of the DFA in the paretic and nonparetic eyes was 4.64±3.90,0.65±0.76 in group 1(P=0.002),and 0.80±0.81,3.21±5.50 in group 2(P=0.01).The difference in the amount of reduction of DFA in the more extorted eye in group 1(paretic eye)vs group 2(nonparetic eye)was insignificant(P=0.30).CONCLUSION:Excyclotorsion in the nonparetic eye has a similar probability in the paretic eye in UCSOP children,and weakening of the ipsilateral IO has a more obvious effect on the decrement of extorsion in the more extorted eye regardless of which eye is paretic.

Modified Harada-Ito Procedure in Acquired Superior Oblique Palsy with Exotropia

Superior oblique palsy is the most common isolated cranial nerve palsy and is commonly associated with exotropia. Modified Harada-Ito procedure can be used to correct excyclotorsion in symptomatic patients. We report a case of acquired superior oblique palsy with exotropia undergoing modified Harada-Ito procedure. A 33 years old man presented with torsional diplopia. On examination there was 10 degrees of left excyclotorsion on double Maddox rod with 25-diopter of exotropia on primary gaze and 20-diopter on lateral gaze suggestive of lateral incomitancy. He underwent a Fells modification of Harada-Ito procedure with bilateral rectus recession. Three months postoperative, he was orthophoric. Modified Harada-Ito procedure is a successful procedure in overcoming torsional diplopia. It is important to identify lateral incomitancy to prevent overcorrection of the horizontal deviation.