Augmented Hummelsheim procedure for paralytic strabismus

Purpose: To report a modification of the Hummelsheim procedure for use in t he management of paralytic strabismus. Methods: Eight patients with paralytic strabismus secondary to third nerve palsy (n=1), sixth nerve palsy (n=3), combined cranial nerve palsy (n=1), o r extraocular muscle damage (n=3) were treated using a modification of the Hummelsheim transposition procedure. The procedure involves half-tendon tra nspositions of the adjacent rectus muscles to the insertion of the paralyze d muscle, coupled with resection of the transposed halves. Further augmenta tion was achieved by surgical or pharmacologic weakening of the ipsilateral (n=6) or contralateral (n=1) antagonist. One patient underwent the procedu re bilaterally. All patients underwent at least fi weeks of follow-up. Results: The mean preoperative primary position deviation in the seven unil ateral cases was 54 prism diopters (Delta) (range: 25-85 Delta). Preoperati ve forced ductions were positive in four cases. Resections varied from 4-8 mm. Ipsilateral antagonist recession varied from 0-14 mm. The mean change w as 52 Delta (range: 25-85 Delta). Five cases were aligned within 15 Delta o f orthotropia at 6 weeks. No cases of anterior segment ischemia or induced vertical deviation were noted. Conclusion: The modified Hummelsheim procedure appears capable of correctin g large angles of strabismus associated with muscle palsy of various etiolo gies. It is safe, amenable to adjustable sutures, and relatively tissue- an d vessel-sparing. Additional study is required to understand more fully the procedure's component effects and its interaction with ocular rotation.