[Outcomes of partial vertical rectus transposition in acquired sixth nerve palsy]

This study aimed to assess the outcomes of partial vertical rectus transposition (PVRT) in acquired sixth nerve palsy (SNP) on distance ocular deviation in primary position (PP), binocular diplopia in PP, head turn, and limitation of abduction.

This retrospective, single center study was conducted at the Regional University Medical Center of Tours between 2004 and 2019. All patients underwent comprehensive orthoptic and ophthalmic examination before and after surgery. Total success was defined as horizontal distance deviation in PP≤10 prism diopters (PD), absence of permanent diplopia in PP, head turn≤5 degrees and absence of any induced vertical deviation at last examination.

Ten patients underwent PVRT with a median delay of 3.3 years (2.3 to 7.3) following the diagnosis of SNP. The median duration of postoperative follow-up was 13 months (3.25 to 25). Seven patients (70%) were considered a total success. The mean distance horizontal deviation in PP was reduced from 25.4±11.7 PD preoperatively to 9.2±11 PD postoperatively. Preoperatively, 10 patients did not cross midline in abduction, compared to 8 patients at the last follow-up examination. Postoperatively, 3 patients had permanent binocular diplopia in PP, and 2 patients had an anomalous head turn.

Although further prospective investigations are needed, PVRT can be considered a safe and effective procedure for acquired SNP.