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

Results of different surgical procedures in superior oblique palsy

Serpil Akar, Birsen Gökyig˘ it, Pelin Kaynak Hekimhan & Ömer Faruk Y lmaz

Beyog˘ lu Eye Education and Research Hospital, Istanbul, Turkey

ABSTRACT:

Purpose: To evaluate the outcome of surgical treatment of superior oblique palsy.

Material and methods: 43 superior oblique palsy(SOP) patients who had undergone surgical treatment between 1992–2003 were analysed retrospectively. In 22 cases (Group I), inferior oblique weakening, in 19 cases (Group II), superior oblique(SO) strengthening and inferior oblique(IO) weakening, in 2 cases (Group III) vertical rectus weakening operations were performed. The mean post-operative follow up period was 12.9 8.5 months. We used Wilcoxon Signed Ranks tests for statistical evaluations.

Results: Abnormal head position had been improved in 93% of patients after the operation. There are statistically significant difference between preoperative near and distance vertical deviations and postoperative near and distance vertical deviations for Group I, Group II (p 0.001, p 0.001, p 0.001, p 0.001). There are significant improvement IO hiperfunction and SO hypofunction (p 0.05, p 0.05).

Conclusion: It is concluded that in treatment of SOP, IO weakening procedure had enough effect in small vertical deviation and SO strengthening had a important effect in the patients who had large vertical deviation.

1INTRODUCTION

Superior oblique palsy is the most common isolated cranial palsy of an extraocular muscle that requires surgery. The most common etiologies include congenital and idiopathic. The most common signs and symptoms include hypertropia, extorsion of the involved eye, head tilt, and/or diplopia. Many strabismologists directly or indirectly still use Knapp’s classification for, described in 1974 which maps the pattern of deviation as measured by the prism and cover test in the nine diagnostic positions of gase (Cogen 2003, Helveston 1992, Knapp 1974).

Surgical treatment is highly effective (Cogen 2003). Treatment is generally directed toward achieving fusion in the practical field of gaze, elimination of abnormal head posture, and reduction in symptoms (von Noorden 2002). It was reported different surgical treatments and results by various surgeon (Cogen 2003, Helveston 1992, Knapp 1974, Saunders 1986).

In this study, our purpose was to evaluate the outcome of surgical treatment of superior oblique palsy.

2MATERIALS AND METHODS

The files of 61 patients with SOP, who were examined between 1992–2003 at the Pediatric Ophthalmology and Strabismus Department of our hospital, were retrospectively studied. This study covers 43 patients who had surgical treatment due to manifested head position or hypertropia, diplopia or image tilting.The study population consisted of 19(44%) female and 24(56%) male patients with ages ranging from 4 to 53 years (mean, 15.82 years).

A complete eye examination was performed for all patients On the basis of these data, we determined classification of SOP as similar to classifications of Knapp(1974), von Noorden (1986).

147

In 22 cases (Group I), IO weakening, in 19 cases (Group II), SO strengthening (17 SO tendon tucking, 2 SO resection) and IO weakening, in 2 cases (Group III), IO weakening and vertical rectus weakening operations were performed. Suitable horizontal surgery was done on patients with horizontal deviations before, during or after oblique surgery.

The ipsilateral IO muscle was weakened by myectomie, recession or anterior transposition (Knapp 1974, von Noorden 1986). SO muscle was weakened by tucking or rezection. It was performed tucks ranging from 12 to 10 mm with 5-0 Dacron nonabsorbable suture (Saunders 1985). The ipsilateral superior rectus was weakened by recession (Cogen 2003).

The mean follow-up period was 12.9 8.5(6–14) months. We used Wilcoxon Signed Ranks tests for statistical evaluations.

Surgery results were evaluated as post-operative findings in their last examinations.

3RESULTS

Forty three patients were included in this series and preoperative data are given on all this cases; postoperative data were available for 43. Table I presents the patient demographics and some of the preoperative data along with the results of intraoperative SO traction testing. Table II, Table III and Table IV compare the preoperative and postoperative near and distance vertical deviations, maximum vertical deviation angles. Table V presents the effects of surgical treatment to abnormal head position in SO Palsy.

There are significant improvement IO hiperfunction and SO hypofunction for Group I, Group II and total cases (p 0.05, p 0.05, p 0.05, p 0.05, p 0.05, p 0.05). Three (7%) patients had mild pseudo Brown syndrome.

Preoperatively 11(38%) of the 29 patients who could be tested for torsion had no excyclotorsion. Postoperatively, 88% of those tested had no torsion. Many patients did not have their postoperative torsion documented, especially those without complaints.

Table I. Patient demographics and preoperative data for 43 cases of superior oblique palsy.

Table II. Comparison of preoperative and postoperative near vertical deviations.

*It wasn’t performed statistically evaluating for Group III because patient’s number was few.

148

Preoperatively 12(70%) of the 17 patients who could be tested for stereoacuity had no stereoacuity. Postoperatively, 95% of those tested had stereoacuity.

4DISCUSSION

The surgical treatment of SOP is done for securing a symptomatic relief, for correcting abnormal head condition and deviation and for increasing concomitance and widening of binocular fixation area as much as possible (von Noorden 2002). The important factors that influence the choice of the surgical methods are the amount of deviation in down view and primary position, existence of paralysis in the muscle, function of other eye muscles, existence of horizontal, vertical or torsion components in deviation and existence of A and V patterns (von Noorden 2002). Knapp (1974) have suggested a treatment schedule based on deviation amount in motility defect and cardinal view positions. In this type of treatment, both the congenital and acquired SOP is viewed in the same group (von Noorden 1986, 2002). On the other hand, Helveston has separated his SOP into two groups as congenital and acquired according to etiology and suggested a new treatment schedule (Helveston 1992). It is advised that presence of extremely loose SO tendon, anomaly of insertion place and even tendon agnosia may be found in congenital SOP. It is reported that, in these cases, functional results are better when the treatment is directed to SO tendon (Helveston 1990). In our study, we also determined the type of surgery according to the results of forced duction test, amount of deviation in primary and cardinal view positions, the degree of IO hyperfunction and SO hypofunction and in accordance with the literature.

Table III. Comparison of preoperative and postoperative distance vertical deviations.

Table IV. Comparison of preoperative and postoperative maximum vertical deviation angles.

Table V. The effects of surgical treatment to AHP in superior oblique palsy.

149

IO weakening operations in SOP are the most commonly used primary surgical procedure (Gonzales 1995, Toosi 1979, von Noorden 2002). Helveston (1996), in his series, has used IO weakening operation as a starting procedure in 90% of his 190 SOP cases and gives successful results. Several authors prefer to retard antagonist IO muscle at start (Parks 1971). We, in our series, have applied weakening operation in only 51% of the cases. We preferred this operation in the cases with IO hyperfunction and with deviation below 25 PD and after the operation, we obtained symptomatic relief, adequate correction in head position, vertical deviation and IO function.

SO tucking surgery is defined by Mc Lean. With this operation, several authors have declared that they obtained successful results in the treatment of SOP with wide deviation angle (Knapp 1971, Saunders 1985,1986). In addition, it is written that it also gives positive results in congenital cases with loose tendons (Helveston 1992, Saunders 1986). It is determined that, in the operation of congenital SOP cases in infant age group, best results are obtained by combining IO weakening and SO tucking (Reynolds 1984). In our series, we also applied SO tucking and IO weakening surgery together to cases which have SO hypofunction with IO hyper function and vertical deviation angle more than 25 PD. We obtained successful results in regards to symptomatic relief and correction of AHP, vertical deviation and IO and SO functions.

In literature, development of iatrogenic Brown syndrome ratio after the SO tucking surgery is given as 17%–60% (Helveston 1996, Simons 1998). Especially, in acquired SO paralysis, SO tendon formation is normal and even a small amount of folding causes symptomatic iatrogenic Brown syndrome (Helveston 1983, Saunders 1985). In order to avoid development of iatrogenic Brown syndrome, it is suggested that folding should be done in SO tendon excess ratio after making intra operative traction test (Saunders 1985). In our series, we have found. 7% residual Brown syndrome. All of our cases, whom we have applied tucking operation, were congenital SOP and forced duction test was made in all cases after the surgery. If the test was negative, surgery was stopped. If the test was positive, tucking amount was reduced and the test was repeated.

CONCLUSION

It is concluded that in treatment of SOP, IO weakening procedure had enough effect in small vertical deviation and SO strengthening had an important effect in the patients who had large vertical deviation.

REFERENCES

1.Cogen, M.S., Roberts, B.W. 2003. Combined superior oblique tuck and adjustable suture recession of the ipsilateral superior rectus for long-standing superior oblique palsy. J AAPOS; 7: 195–9.

2.Gonzales, C., Cinciripini, G.1995. Anterior transposition of the inferior oblique in the treatment of unilateral superior oblique palsy. J Pediatr Ophthalmol Strabismus; 32: 107–13.

3.Helveston, E.M., Ellis, F.D. 1983. Superior oblique tuck for superior oblique palsy. Aust J Ophthalmol 11: 215–20.

4.Helveston, E.M. 1990. Classification for superior oblique palsy. In: Haik BG,ed. Transactions of Symposium on Oculoplastic Surgery, Strabismus, and Pediatric Ophthalmology, Horofare. Slack: 1–10.

5.Helveston, E.M., Krach, D., Plager, D.A., Ellis, F.D. 1992. A new classification of superior oblique palsy based on congenital variations in the tendon. Ophthalmology 99: 1609–15.

6.Helveston, H.M., Mora, J.S., Lipsky, S.N. 1996. Surgical treatment of superior oblique palsy. Trans Am Ophthalmol Soc 94: 315–2

7.Knapp, P. 1974. Classification and treatment of superior oblique palsy. Am Orthopt J 24: 18–22.

8.Parks, M.M., Hamtil, L.W. Surgical management of isolated cyclovertical muscle palsy. J Ped Ophthalmol Strabismus 1971; 8: 145–152.

9.Reynolds, J.D., Biglan, A.W., Hiles D.A. 1984. Congenital superior oblique palsy in infants. Arch Ophthalmol 102: 1503–5.

10.Saunders, R.A., Tomlinson, E. 1985. Quantitated superior oblique tendon tuck in the treatment of superior oblique muscle palsy. Am Orthopt J35: 81–89.

150

11.Saunders, R.A. 1986. Treatment of superior oblique palsy with superior oblique tendon tuck and inferior oblique muscle myectomy. Ophthalmology 93: 1023–7.

12.Simons, B.D., Saunders, T.G., Siatkowsky, R.M., et al. 1998. Outcome of surgical management of superior oblique palsy:a study of 123 cases. Binocul Vis Strabismus Q 13: 273–87.

13.Toosi, S.H., von Noorden, G.K. 1979. Effect of isolated inferior oblique myectomy in the management of superior oblique palsy. Am J Ophthalmol 88: 602–8.

14.von Noorden, G.K., Murray, E., Wong, S.Y. 1986. Superior oblique paralysis. A rewiew of 270 cases. Arch Ophthalmol 104: 1771–6.

15.von Noorden, G.K. 2002. Paralytic Strabismus in Binocular Vision and Ocular Motility, Theory and Management of Strabismus. 6th ed. St. Louis:Mosby: 449–450.

151