Transactions 29th European Strabismological Association Meeting – de Faber (ed) © 2005 European Strabismological Association, ISBN 04 1537 211 9

Transposition procedure for abducens palsy: 10 year-results

R. Autrata, K. Vodicková, J. Rehu˚rek

Department of Pediatric Ophthalmology, Faculty of Medicine,

Masaryk University Hospital, Czech Republic

ABSTRACT: Authors evaluated a long-term outcomes of two surgical methods for the treatment of six nerve palsy. Eighty nine patients with paralytic strabismus secondary to sixth nerve palsy undergone surgery in the period from January 1993 to October 2003. Group A included 46 patients, who were treated using a large recession of the medial rectus combined with a supramaximal resection of the lateral rectus. Group B comprised 43 patients in whom were performed the Hummelsheim transposition procedure with or without resection of transposed half-tendon vertical muscles, always combined with recession of medial rectus. The modified split-tendon Hummelsheim procedure involves half-tendon transpositions of the adjacent rectus muscles to the insertion of the paralyzed muscle, coupled with resection of the transposed halves. The mean follow-up was 34.6 months (range, 6 to 114 months). The primary position deviation and the occurence of diplopia after one surgical procedures were compared in the both groups preoperatively and postoperatively. For statistical analysis was used the Student-t test.

The mean preoperative primary position deviation in the Group A and B was 56 prism diopters (PD), (range: 28 to 80 PD), and 59 PD (range: 30 to 90 PD), respectively. Diplopia was present in 78% of Group A patients, and 89% of Group B patients. At last visit postoperatively, the mean primary deviation decreased to 27 PD (range: 6 to 40 PD) in A group, and 8 PD (range: –8 to 26 PD), (P 0.038). Diplopia postoperatively was present in 28 % of A group, and 9% of B group (P 0.029). No cases of anterior segment ischemia or induced vertical deviation were found.

In summary, the use of the augmented half-tendon transposition procedure resulted in a significantly better primary position of eyes postoperatively, than only the graded recession-resection procedure of the horizontal muscles.

1INTRODUCTION

Six nerve palsy is the most common of the acquired palsies, occuring less commonly on a congenital basis. After diagnosis and treatment for any underlying conditions, management of the strabismus resulting from the sixth nerve palsy includes observation of signs of contracture of the antagonist medial rectus or of recovery of the paretic lateral rectus. During the waiting period of at least 6 months, alternate patching may help to prevent contracture of the medial rectus of the involved eye. Alternatively, botulinum toxin may be injected into the medial rectus to prevent contracture, but it cloudes the clinical picture when neurological examination may change. After 6 months of waiting for possible return of sixth nerve function, surgical treatment is considered. A graded medial rectus recession and lateral rectus resection for the appropriate amount of esotropia can be performed. In an eye with a totally paralyzed lateral rectus and esotropia in the range of 50 prism diopters(PD), the medial rectus should be recessed more than 8 mm. Little is gained from only resecting the lateral rectus if it is totally paralyzed. A muscle transfer procedure may be necessary to keep the eye in the straight position and also to obtain some abducting force. The Hummelsheim procedure consists of transposing the lateral halves of the vertical recti to the lateral rectus. It is relatively tissueand vessel-sparing compared with other procedures. To augment

359

the effect of the procedure, and possibly improve abduction and the field of single binocular vision, the ipsilateral medial rectus also may be recessed (l,2) or injected with botulinum toxin (3). The modified Hummelsheim procedure with augmentation achieved by resection of the transposed halves is capable to correct a very large angles of deviation associated with abducens palsy of various etiologies. (7)

Our study evaluated the efficacy of the horizontal muscle surgery and the Hummelsheim trans-position procedure with or without augmentation in long term follow-up.

2PATIENTS AND METHODS

A retrospective review analyzed 89 patients (42 children, 47 adults) with paralytic strabismus secondary to sixth nerve palsy, who undergone surgery in the period from January 1993 to October 2003. The mean follow-up was 34.6 months (range, 6 to 121 months). The sixth nerve palsy is refered whether it was a complete palsy or an incomplete paresis. The abduction deficit and angle of deviation were measured in prism diopters (PD) by simultaneous prism and cover test in the primary position at distance fixation. The etiology of the palsy were: congenital, traumatic, neoplastic, vascular, diabetic, hydrocephalus or unknown. A complete palsy was defined as an inability to abduct the eye to the midline or limitited abduction only to the midline. The inclusion criteria: more than six months from onset, inability to abduct 1 or both eyes, distance esotropia more than 25 PD, diplopia in primary position at distance fixation, visual acuity at least 6/60 in each eye, no previous treatment with botox or surgery. The following data from each patient were recorded: diagnosis and duration of palsy, prism-cover measurements in the primary position at distance, presence of diplopia, qualitative assessment of ductions, coexisting ocular disease, details of surgical procedure and intraoperative passive forced ductions and complications (anterior segment ischemia or induced vertical deviation).

Group A included 46 patients treated using a large recession of the medial rectus combined with a supramaximal resection of the lateral rectus. Group B comprised 43 patients in whom were performed the Hummelsheim transposition procedure with (34 patients) or without resection of transposed half-tendon vertical muscles, always combined with recession of medial rectus. The modified split-tendon Hummelsheim procedure involved half-tendon transpositions of the adjacent vertical rectus muscles to the insertion of the paralyzed muscle, coupled with resection of the transposed halves. The superior and inferior rectus muscles were carefully divided in half in a longitudinal fashion for approximately 15 mm using a muscle hooks. Care also was taken to avoid injury to the anterior ciliary vessels in the portions of muscle not used for transposition. Doublearmed 6-0 vicryl suture was placed at a predetermined distance posterior to the muscle insertion (in the cases with resection of the transposed muscles: the amount of 5–8 mm of muscle was resected).

The primary position deviation and the occurence of diplopia after one surgical procedures were compared in the both groups preoperatively and postoperatively. For statistical analysis was used the Student-t test.

3RESULTS

Data and results of all patients included in the both study groups are summarized in Table 1.

The mean preoperative primary position deviation in the Group A and B was 56 prism diopters (PD), (range: 28 to 80 PD), and 59 PD (range: 30 to 90 PD), respectively. Diplopia was present in 78% of Group A patients, and 89% of Group B patients. At last visit postoperatively, the mean primary deviation decreased to 27 PD (range: 6 to 40 PD) in A group, and 8 PD (range: 8 to 26 PD), (P 0.038). Diplopia postoperatively was present in 28% of A group, and 9% of B group (P 0.029). No complications in terms of anterior segment ischemia or induced vertical deviation were found.

360

Table 1. Data for all patients, preoperative and postoperative status.

4DISCUSSION

The management of the sixth nerve palsy depends on the underlying cause. If recovery of the chronic palsy does not occur, surgery is necessary. Few studies have been conducted on the outcome of patients with chronic sixth nerve palsy and paresis. Chronic is defined, for the present study, as longer than 6 months in duration since onset. There is controversy about the optimum timing and mode of treatment for these patients. In a survey of 201 pediatric ophthalmologists and neuro-ophthalmologists regarding the timing of strabismus surgery in acute traumatic sixth nerve palsy, 26% would wait more than 6 months from onset before performing surgery, expecting further recovery (8). Although some physicians advocate continued conservative management at 6 months from onset, others advocate botulinum toxin (botox) injection to the ipsilateral medial rectus (9) or strabismus surgery with or without botox (10).

Muscle transposition surgery often is required in those cases in which the degree of muscle palsy is severe and agonist action is negligible. Numerous procedures to accomplish this purpose and subsequent modifications have been described over the years. (11) The goals of the surgical procedure are to improve the range of single binocular vision, restore ocular alignment in the primary position, and improve cosmesis, while minimizing the risk of ocular complications.

A variety of transposition procedures have been promoted for the treatment of abducens palsy and other complex paralytic ocular motility abnormalities (3,12,13,14,15). Full tendon transposition procedures, although reasonably effective when severe duction deficits are present, often result in undercorrection, necessitating recession of the ipsilateral antagonist rectus muscle to achieve successful alignment (2). This method carries a significant risk of anterior segment ischemia. In 1997, Foster (16) described a new procedure consisted of a full tendon rectus muscle transposition of the vertical rectus muscles to the lateral rectus muscle insertion, augmented with a posterior fixation fixation suture in each of the transposed muscles. The posterior fixation suture used in this technique further directed vector forces of the transposed muscles laterally. Paysse (17) reported that use of the vessel-sparing three fourths partial tendon transposition modification of this technique is effective for the treatment of a variety of complex vertical and horizontal paralytic ocular motility disorders. In this modification, only 75% of the width of the muscles was transposed, taking care to leave one intact anterior ciliary artery in each nontransposed segment of the muscle. Posterior fixation suture was placed on each of the transposed muscles on the side adjacent to the paralyzed muscle 12 to 15 mm posterior to the limbus to augment the effect of the transposition. Mean distance deviation in primary position improved from 48 PD preoperatively to 6 PD after surgery. In our study, the similar improvement in horizontal deviation was achieved

361

by the resection 5 to 8 mm of the half-tendon vertical transposed muscle. The mean deviation 59 PD preoperatively changed to 8 PD post-operatively. Even if the ipsilateral medial rectus muscle was recessed, in no patient the anterior ischemia has been developed. The wide range of corrections achieved for primary position deviation is comparable to that reported in other studies (7,8,16–19).

Our results in patients with only the resection-recession procedures of the horizontal muscles demonstrated a low ability to correct medium to large large angles of deviation compared to augmented transposition procedures. The data of our study suggest the augmented Hummelsheim procedure may not have significant limitations with regard to preoperative angle.

Botulinum toxin injected into the ipsilateral medial rectus has been advocated, in selected patients, for treating chronic sixth nerve palsy (9). Results in another study (8) provide little support for this botox treatment, because in only 1 (10%) of 10 patients was successful. Repka et al

(9) reported success in 9 (41%) of 22 patients with chronic sixth nerve palsy of 5 or more months duration, but defined success somewhat differently; they included patients who had 50% improvement in their esotropia. Even excluding these cases, the same author reported a 32% success rate in restoring single binocular vision in primary position. Their patients received 1 to 5 injections of botox and were followed for an unspecified time. Taken together, the results of botox injection alone for chronic sixth nerve palsy are less than encouraging. In conclusion, our results confirm the effectivenes of the augmented rectus muscle transposition procedure in abducens palsy. The procedure resulted in marked improvement in head posture and ocular alignment in the primary position, with partial restoration of abduction. Additionally, the procedure was safe without complications in terms of anterior segment ischemia or induced vertical deviation.

REFERENCES

1.Uribe LE. Muscle transplantation in ocular paralysis. Am J Ophthalmol 1968;65:601–607.

2.Rosenbaum AL, Foster RS, et al. Complete superior and inferior rectus transposition with adjustable medial rectus recession for abducens palsy. Strabismus 1984;2:599–605.

3.Rosenbaum AL, Kushner BJ, Kirschen D. Vertical recrus muscle transposition and botulinum toxin(Oculinum) to medial recrus for abducens palsy. Arch Ophthalmol 1989;107:820–823.

4.Saunders RA, Phillips MS. Anterior segment ischemia after three rectus muscle surgery. Ophthalmology 1988; 95:533–537.

5.Saunders RA, Sandall GS. Anterior segment ischemia syndrome following rectus muscle transposition. Am J Ophthalmol 1982;93:34–38.

6.Saunders RA, Bluestein EC, Wilson ME, et al. Anterior segment ischemia after strabismus surgery. Surv Ophthamol 1994;38:456–466.

7.Brooks SE, Olitsky SE, et al. Augmented Hummelsheim Procedure for Paralytic Strabismus. J Pediatric Ophthalmol Strabismus 2000, 37:189–195s.

8.Holmes JM, Leske DA et al. Initial treatment outcomes in chronic sixth nerve palsy. J AAPOS 2001;5:370–376.

9.Repka MX, Lam GC, Morrison NA. The efficacy of botulinum neurotoxin A for the treatment of complete and partially recovered chronic sixth nerve palsy. J Pediatr Ophthalmol Strabismus 1994;31:79–83.

10.Rosenbaum AL, Kushner BJ, Kirschen D. Vertical rectus muscle transposition and botulinum toxin (Oculinum) to medial rectus for abducens palsy. Arch Ophthalmol 1989;107:820–823.

11.Helveston EM. Muscle transposition procedures. Surv Ophthamol 1971;16:92–97.

12.Mc Manaway J.W., Buckley E.G., Brodsky M.C. Vertical rectus muscle transpostion with intraoperative botulinum injection for chronic sixth nerve palsy. Graefes Arch Clin Exp Ophthalmol 1990;228:401–406.

13.Hiatt RL. Transposition procedures in strabismus. Ann Ophthalmol 1986;18:332–336.

14.Cline RA., Scott WE. Long-term follow-up of Jensen procedures. J Pediatr Ophthalmol Strabismus 1988; 25:264–269.

15.Maruo T., Iwahige H. et al. Results of surgery for paralytic esotropia. Jpn J Ophthalmol 1996;40:229–234.

16.Foster RS. Vertical muscle transposition augmented with lateral fixation. J AAPOS 1997;1: 20–30.

17.Paysse EA, Mc Creery KMB, et al. Use of augmented rectus muscle transposition surgery for complex strabismus. Ophthalmology 2002;109:1309–1314.

362

18.Burke JP, Ruben JB, Scort WE. Vertical transposition of the horizontal recti (Knapp procedure) for the treatment of double elevator palsy: effectiveness and long-term stability. Br J Ophthalmol 1992;76: 734–737.

19.Burke JP, Keech RV: Effectiveness of inferior transposition of the horizontal rectus muscles for acquired inferior rectus paresis. J Pediatr Ophthalmol Strabismus. 1995;32:172–177.

20.King AJ, Stacey E, Stephenson G. Spontaneous recovery rates for unilateral sixth nerve palsies Eye 1995;9:476– 478.

21.Savino PJ, Hilliker JK, Casell GH, Schatz NJ. Chronic sixth nerve palsies: are they really harbingers of serious intracranial disease? Arch Ophthalmol 1982;100:1442–1444.

22.Golnik KC, Miller NR. Late recovery of function after oculomotor nerve palsy. Am J Ophthalmol 1991;111:566–570.

363