Posterior fixation following vertical muscle transposition as treatment of total sixth cranial nerve paralysis

Introduction: Vertical muscle transpositions are considered as the classic procedures for total VIth nerve palsy, whereas weakening of the controlateral medial rectus muscle requires a residual function of the paretic muscle. The aim of this study is to investigate the cumulative effects of these two different surgical approaches applied to the same patients. Patients and methods: 2 patients (M 48 years and F 55 years) with posttraumatic total VIth nerve paralysis were operated in two steps more than 1 year after trauma. The first procedure consisted of a Hummelsheim transposition of the vertical recti and was followed by a posterior fixation of the controlateral medial rectus. Results: The vertical transposition resulted in the improved position of the paretic eye and in the disappearance of diplopia in primary position. The posterior fixation considerably improved the motility in abduction of the paretic eye and consequently provided the patients with widened binocular field of fusion. Conclusion: Posterior fixation of the controlateral medial rectus efficiently complements the vertical transposition in cases of total VIth nerve palsy. This combined effect remained stable during a 2 years follow-up in our patients.