Frequency of the superior rectus muscle overaction/contracture syndrome in unilateral fourth nerve palsyAndrea Molinari, MD,a and Maria Cristina Ugrin, MDb

INTRODUCTION Superior oblique palsy is accompanied in most cases by overaction of the muscle’s ipsilat-

Author affiliations: aHospital MUniversidad de Buenos Aires, Ar

Institutions at which the studyClinicas.

Submitted April 18, 2009.Revision accepted August 20,Reprint requests: Andrea Mol

Mariana de Jesus y Nicolas ArteCopyright � 2009 by the Am

Strabismus.1091-8531/2009/$36.00 1

doi:10.1016/j.jaapos.2009.08

Journal of AAPOS

eral antagonist, the inferior oblique muscle. Overaction and contracture of the ipsilateralsuperior rectus muscle in patients with unilateral fourth (trochlear) nerve palsy is seldomdiscussed in the literature. The purpose of this study is to evaluate the frequency of superiorrectus muscle overaction/contracture syndrome in patients with unilateral trochlear nervepalsy.

SUBJECTS ANDMETHODS

The records of 198 patients with unilateral trochlear nerve palsy examined by the authorsbetween July 1987 and July 2008 were reviewed retrospectively. All patients underwent

complete eye examination with measurement of the deviation in the 9 positions of gazeand with the head tilted to both sides in all cooperative patients. Selection criteria for su-perior rectus muscle overaction/contracture syndrome in these patients were as follows:vertical deviation of 15D or larger in primary position, equal or larger hypertropia withthe ipsilateral forced tilt test than with the eyes looking straight ahead, more than 5D hyper-tropia of the affected eye in horizontal gaze to the same side, hypertropia in all upgazes, andoveraction of the contralateral superior oblique muscle.

RESULTS Of 198 patients, 33 (16.6%) met the selection criteria for superior rectus muscle overac-

tion/contracture syndrome.

CONCLUSIONS Superior rectus muscle overaction/contracture syndrome frequently occurs in unilateral

superior oblique palsy. ( J AAPOS 2009;13:571-574)

Superior oblique palsy profoundly influences the in-nervational balance of the entire oculomotor sys-tem, potentially affecting cyclovertical muscles in

both eyes. In most cases the condition is associated withoveraction of the inferior oblique muscle. In some casesthe yoke muscle of the underacting superior oblique, thecontralateral inferior rectus, can become overactive.1

Underaction of the affected superior oblique muscle canbe mild or undetectable without the presence of a freshparalysis, which is uncommon.

Some references in the literature discuss the overactionof the ipsilateral superior rectus muscle.2,3 The coexistenceof this overaction, which can lead to superior rectus musclecontracture, is easily understood if one considers that thesuperior rectus is also an antagonist of the paretic superioroblique in its vertical action.4 The purpose of this study isto evaluate the frequency of superior rectus muscle overac-tion/contracture syndrome in patients with unilateraltrochlear nerve palsy.

etropolitano, Quito, Ecuador, bHospital de Clinicas,gentinawas conducted: Hospital Metropolitano and Hospital de

2009.inari, MD, Centro Medico Meditropoli, Oficina 211, Av.ta, Quito, Ecuador (email: ams@pi.pro.ec).erican Association for Pediatric Ophthalmology and

0.015

This syndrome has been named the superior rectus mus-cle overaction/contracture syndrome because in some casesit is easier to recognize the characteristics of an overaction(in the upper field of gaze), whereas in other patients thecharacteristics of a contracture (in the lower field of gaze)are more obvious. The most relevant clinical characteris-tics found in patients with superior rectus muscle overac-tion/contracture syndrome in unilateral superior obliquepalsies are as follows: first, hypertropia in all upgazes; sec-ond, large difference in vertical deviation with forced headtilt, maximum to the affected size; third, more than 5D ofhypertropia in the ipsilateral version; and finally, highdegrees of compensatory vertical fusional amplitudes.5

Patients usually have a significant vertical deviation in pri-mary position, but it is important to note that this can alsobe present in patients with marked overactions of the infe-rior oblique muscle or in cases where more than 1 cyclo-vertical muscle are overacting and the ipsilateral superiorrectus muscle function is normal.

Subjects and Methods

Files of all patients with the diagnosis of unilateral trochlear nerve

palsy examined by the authors between July 1987 and July 2008

were reviewed retrospectively. Diagnosis of unilateral trochlear

nerve palsy in these patients was made based on the presence of

the following findings: incomitant hypertropia, usually larger in

adduction; increase of the hypertropia when tilting the head

toward the hypertropic eye; and evidence of underaction of the

571

FIG 1. One-year-old patient with left superior rectus overaction/contracture syndrome (A). Note increasing hypertropia in abduction and with thehead tilted to the left (B).

572 Molinari and Ugrin Volume 13 Number 6 / December 2009

ipsilateral superior oblique muscle, overaction of the ipsilateral

inferior oblique, or overaction of the ipsilateral superior rectus

or the contralateral inferior rectus.

All patients underwent a complete eye examination. In all coop-

erative patients deviation in the 9 positions of gaze and with the head

tilted to either side was measured by prism and cover test when fix-

ing at a target 6 m distant. In 3 patients (aged 1 to 3 years) measure-

ments could not be obtained due to lack of cooperation.

Nonetheless, these patients were included since analysis of photo-

graphs taken of them indicated that they fulfilled the selection

criteria (Figure 1).

Selection criteria for superior rectus muscle overaction/con-

tracture syndrome in these patients were as follows: vertical devi-

ation in primary position of 15 D or larger, equal or larger

hypertropia with the ipsilateral forced tilt test than observed

with the eyes looking straight ahead, more than 5D hypertropia

of the affected eye in the ipsilateral version, hypertropia in all up-

gazes, and overaction of the contralateral superior oblique muscle.

Results

Of the 198 patients with unilateral trochlear nerve palsy, 33(16.6%) met the selection criteria for superior rectus mus-cle overaction/contracture syndrome (95% CI, 11.4-21.8).Of these, 16 were male. The average age for onset of symp-toms was 20.58 years (range, 6 months to 74 years); the av-erage age at diagnosis was 34.42 years (range, 1-74). Theetiology of the condition was congenital in 31 cases andvascular in 2 cases. Eye fixation was with the paretic eyein 15 cases and with the sound eye in 18 cases.

Measurements of this group of 33 patients can be seen inTable 1. Measurements of an equal number of patients

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Table 1. Measurements of patients with unilateral trochlear nervepalsy and associated superior rectus overaction/contracturesyndrome

Vertical deviation Average (range)

Primary position 21.4D (15D-35D)Ipsilateral forced tilt 29.53D (22D-45D)Contralateral forced tilt 11.8D (2D-25D)Difference forced tilt

(difference betweenipsilateral and contralateral)

17.3D (10D-30D)

Ipsilateral version 15.66D (6D-30D)

Table 2. Measurements of patients with unilateral trochlear nervepalsy and no superior rectus muscle overaction/contracturesyndrome

Vertical deviation Average (range)

Primary position 8.96D (2D-25D)Ipsilateral forced tilt 13.83D (4D-30D)Contralateral forced tilt 3.73D (0D-16D)Difference forced tilt 12.28D (2D-28D)Ipsilateral version 5.03D (0D-18D)

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randomly selected from among the patients with unilateraltrochlear nerve palsy but no superior rectus muscle overac-tion/contracture syndrome are shown in Table 2.

Discussion

Jampolsky and Scott6 first described superior rectus muscleoveraction/contracture syndrome in 1964, when they ob-served the pheomenon in selected patients with unilateralsuperior oblique palsy. They later noted that superior rec-tus contracture should be suspected in cases of superior ob-lique palsy where (1) the deviation in primary position isover 15D, (2) the hypertropia differs on head tilt testing,and (3) a significant vertical deviation is present in gazeto the side of the superior oblique palsy.7,8 Jampolskyand Scott proposed that the contracture is due to the man-ifest vertical defect that occurs when fusion is disruptedduring sleep or intermittently during casual seeing. Thiscontracture can sometimes but not always be documentedwith a positive forced duction test.9,10 Jampolsky11 addedthat this syndrome is not seen exclusively in superior obli-que palsies but also in several other entities such as dissoci-ated vertical deviation, thyroid myopathy, orbital floorfracture, sensory exotropia, and monocular elevation defi-cit. Treatment of patients with superior rectus muscle con-tracture should include recession of the involved superiorrectus muscle.8

Unilateral trochlear nerve palsy can produce a variableeffect on the innervational balance of the oculomotor sys-tem, with secondary overaction of different cycloverticalmuscles, with the result that cases may present witha wide variety of clinical pictures. Classifications of the dif-ferent clinical presentations of unilateral trochlear nervepalsy have been published by several authors.12-15

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It would be difficult for us to classify all of our patientswith superior rectus muscle overaction/contracture syn-drome into 1 of these groups, although they would proba-bly fit best in group 5 of Souza-Dias’ classification ofpatients with hypertropia larger across the superior field15;however, some of our patients also had a large deviationwhen looking toward the ipsilateral lower field due to thesuperior rectus contracture. The evidence of restrictionto depression was not always clear clinically, but it couldbe demonstrated during surgery with positive forced duc-tion testing in abduction.16

To our knowledge, few reports in the literature haveinvestigated the frequency of secondary superior rectusmuscle overaction/contracture. Von Noorden andcolleagues2 found a prevalence of 19% in 202 patientswith unilateral trochlear nerve palsy, confirmed by forcedduction testing. This percentage is close to the rateof 16.6% in our patients. Similar to von Noorden, wefound no fixation preference for the sound eye in ourpatients.1,4

The most relevant sign of superior rectus muscle overac-tion/contracture syndrome in unilateral trochlear nervepalsy is a positive Bielschowsky head tilt test. In all of ourpatients, the hypertropia in the ipsilateral head tilt positionwas larger than in primary position. Several of our patientswith no superior rectus muscle overaction/contracture hadthe same amount of deviation in primary position as withipsilateral head tilt.

In conclusion, contralateral superior rectus muscle over-action/contracture occurs frequently in patients with uni-lateral superior oblique palsy. Clinicians should be awareof this possibility when planning strabismus surgery forthese patients.

Acknowledgment

The authors thank Dr. Arthur Jampolsky for help and support in thepreparation of this article.

References

1. Fells P. Management of Paralytic Strabismus. Br J Ophthalmol 1974;58:255-65.

2. von Noorden GK, Murray E, Wong SY. Superior oblique paralysis.Arch Ophthalmol 1986;104:1771-6.

3. Jampolsky A. Vertical strabismus surgery. In: Symposium on Strabis-mus. Transactions of the New Orleans Academy of Ophthalmology.St. Louis, MO: Mosby; 1971:366.

4. Prieto Diaz J, Souza-Dias C. Estrabismo. 5th ed. Buenos Aires:Ediciones Cientı́ficas Argentinas; 2005:323-8.

5. Jampolsky A. A new look at the head tilt test. In: Fuchs AF,Brandt TH, Buttner U, Zee DS, editors. Contemporary ocular motorand vestibular research: A tribute to David A. Robinson. Stuttgart:Thieme Verlag; 1994:432-9.

6. Jampolsky A, Scott AB. Ocular deviations. Intl Ophthalmol Clin1964;4:700.

7. Jampolsky A. Oblique muscle surgery of the A-V patterns. J PediatrOphthalmol Strabismus 1965;2:31-6.

8. Jampolsky A. Superior rectus overaction/contracture syndrome, Con-sejo Latinoamericano de Estrabismo. Actualidades del Estrabismo

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Latinoamericano. Buenos Aires: Ciba Vision, Novartis;1998:193-206.

9. Jampolsky A. Management of vertical strabismus. In: Symposium onStrabismus. Transactions of the New Orleans Academy of Ophthal-mology. St. Louis, MO: Mosby; 1971:366-85.

10. Jampolsky A. Management of acquired (adult) muscle palsies. In:Symposium on Strabismus. Trans New Orleans Acad Ophthalmol.St. Louis, MO: Mosby; 1976:148-57.

11. Jampolsky A. Management of vertical strabismus. In: Pediatric Oph-thalmology Strabismus: Trans New Orleans Acad Ophthalmol. NewYork, NY: Raven Press; 1986:141-71.

12. Scott W, Kraft S. Classification and surgical treatment of superioroblique palsies. In: Pediatric ophthalmology and strabismus: Trans

An Eye on the Arts - Th

Of gogle eyesThis impediment is never healed but in a very yunto there is appointed no manner kynde ofthat is to saye, to laye the chyldes in hys cradthe light, and not to turne hys eyes on eygoggle, then set the cradell after such a fourside: that is, on the same side from whence hehe maye dyrecte them to the same part, and soAnd in the nyght there ought to be a candell setand remove hys eyes from the evel custome. Alsgood in thys case to be set, as is sayde afore. Furbesides hys eyes, to constrayne the syght to be

—Rick Bowers (from Thomas Phaer and The Bo

New Orleans Acad Ophthalmol. New York, NY: Raven Press;1986:15-38.

13. Knapp P. Diagnosis and surgical treatment of hypertropia. AmOrthop J 1971;21:29-37.

14. Knapp P, Moore S. Diagnosis and surgical options in superior obliquesurgery. Int Ophthalmol Clin 1976;16:137.

15. Souza-Dias C. The surgical treatment of unilateral IV nerve palsy.Am Orthopt J 1992;42:16-24.

16. Jampolsky A. Superior rectus contracture syndrome. In: Lenner-strand G, editor. Update on strabismus and pediatric ophthalmology,Proceedings of the Joint ISA and AAPOS Meeting, Vancouver,Canada, June 19-23, 1994. Ann Arbor, MI: CRC Press Inc; 1995:279-82.

e Arts on the Eye

onge chylde, even at the begynnynge where-medicine but onelye an order of kepynge;elle that he maye beholde directe agaynstether of both sides. If yet he begynne tome that the light may be on the contraryturneth hys eyes, so that for desire of lyghteby custome brynge them to the due fashion.in lykewyse, to cause hym to behold upon ito grene clothes, yelowe, or purple, are veryethermore, a coyfe or a byggen stondyng outholde direct forwarde.

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