Large Recession of the Horizontal Recti for Treatment of Nystagmus EUGENE M. HELVESTON, MD, FORREST D. ELLIS, MD, DAVID A. PLAGER, MD

Abstract: Ten patients had large recession of four horizontal recti at one procedure for treatment of nystagmus. Six patients had congenital motor nystagmus, two had oculocutaneous albinism, and two had optic nerve hypoplasia. Anomalous head posture with null point was also present in five patients. The rectus muscles were placed at or behind the equator in all but one case. Three patients with both esotropia and nystagmus had the medial recti placed 1 mm behind the equator and the lateral recti or at 1 mm anterior to the equator. Visual acuity improved an average of 1 line at distance and/or near in 8 patients who cooperated for testing . Although nystagmus was not eliminated in any patient, its amplitude decreased in eight of ten patients, and anomalous head posture improved in three of five patients. In all patients, near vision was better than distance vision both preoperatively and postoperatively. Ductions were diminished minimally after the large recession and there were no other complications from surgery. Ophthalmology 1991; 98: 1302-1305

Congenital nystagmus develops during the first 2 to 4 months of age as a primary motor defect or secondary to a binocular afferent sensory defect such as optic nerve hypoplasia, macular hypoplasia, or bilateral cataracts. I The eye movements can be pendular, jerk, or both and usually vary in speed and amplitude with time, gaze position, convergence/accommodation, and level of excitement. The unstable retinal image from nystagmus reduces vision in an otherwise normal eye and further reduces vision in a compromised eye. Nystagmus can be dampened and vision improved in some cases by voluntary or induced convergence and also by shifting gaze to a position where eye movement is reduced or stopped in what is called the null or neutral zone. This maneuver is usually associated with anomalous head posture. Treatment proposed to dampen nystagmus and improve vision includes: (1) prism or minus lenses to induce Originally received: October 28, 1990. Revision accepted: April 29, 1991. From the Section of Pediatric Ophthalmology, Department of Ophthal· mology, Indiana University School of MediCine, Indianapolis. Reprint requests to Eugene M. Helveston, MD, 702 Rotary Circle, Indianapolis, IN 46202.

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convergence; (2) prism to shift gaze;3 (3) weakening and strengthening of the extraocular muscles to stimulate convergence tonus or to shift the null to or near the primary position;3,4 and (4) pharmacologic denervation of the extraocular muscles. 5 This report describes our experience with another surgical approach for the treatment of nystagmus, namely, simultaneous large recession of the four horizontal rectus muscles as described first by Bietti and Bagolini, 6 reintroduced by Limon and Bernadeli,? and most recently discussed by von Noorden and Sprunger. s

MATERIALS AND METHODS All patients undergoing four horizontal rectus muscle recession for treatment of manifest nystagmus between February 1988 and May 1990 were included. Preoperative and postoperative evaluation included Snellen measurement of visual acuity at distance and near when possible, measurement of alignment with the prism and cover test both at distance and near, evaluation of versions and ductions, and documentation of head posture assumed to achieve best vision. Preoperative evaluation also included assessment of sensory status, pupillary reactions, cycloplegic retinoscopy, and ophthalmoscopy.

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RECESSION OF THE HORIZONTAL RECTI

The nystagmus pattern was graded as jerk or pendular, and speed was graded as rapid, moderate, or slow. Head posture for best vision (least nystagmus) was described as the approximate degrees of deviation of the face (head) horizontally or vertically away from the straight position. Patients who had improved vision when nystagmus was dampened by convergence as manifested by improved near vision or when the patient assumed an abnormal head posture and those with nystagmus and coexisting esotropia were selected for simultaneous recession of the four horizontal rectus muscles. The four rectus muscles were placed at or just behind the functional equator; that is, 11.5 mm or more from the medial limbus and 13 mm or more from the lateral limbus except in cases of esotropia. In three cases with esotropia, the lateral recti were recessed to a point just anterior to the equator and the medial recti were recessed behind the equator. Selected patients had preoperative and/or postoperative video recording of eye movements. Patients were examined postoperatively at I day, I week, 8 weeks, and routinely after that on an as needed basis. Ten patients underwent four muscle recession for treatment of manifest nystagmus. There were 5 females and 5 males, ranging in age from 14 months to 51 years, in the study. All patients had rapid-to-moderate speed, large amplitude, mostly pendular but at times jerk nystagmus, which was evaluated by observations aided by detailed study ofthe video image in five patients. Six patients had esotropia ranging from 25 to 45 prism diopters (PD). The remaining patients had straight eyes. Patients 5 and 6 had stereo acuity, measured preoperatively 40 and 80 seconds of arc disparity, respectively. Five patients assumed a head turn ranging from 15° to 45° to gain a null or neutral zone. The remaining patients had a straight head posture. Visual acuity in the better eye ranged from 20/30 to 20/125. Two patients had oculocutaneous albinism and two patients had optic nerve hypoplasia causing decreased vision and also had nystagmus, which further decreased vision. The remaining six patients had congenital motor nystagmus. Seven of ten patients had retroequatorial recession of all four horizontal recti. Patients I, 4, and 8 had recession of the lateral recti to II mm or 12 mm from the limbus, slightly anterior to the equator, because of a preoperative esodeviation of 45 PD in two patients and 30 PD in the third patient. Patient 7 had 25 PD of exotropia preoperatively. Patient I had recession ofthe medial recti to the equator and the lateral rectus to I mm anterior to the equator.

RESULTS After surgery, the nystagmus was reduced in frequency and amplitude in eight patients. Complete results are recorded in Table I. This was determined by observation of the patients, comparison of preoperative and postoperative video recordings in patients 7,8, and 9, and reports from the patients. Visual acuity improved in seven of eight patients who cooperated for acuity testing at distance,

near, or both; however, this improvement was small, averaging only one line. All patients had either straight eyes or a residual small angle strabismus (patients 1,4, 7, and 8) postoperatively. The anomalous head posture was lessened or the head was straight postoperatively in three of five patients who had abnormal head posture preoperatively. Two patients had no change in head posture. No patient reported diplopia or decreased visual acuity. The two patients who had stereopsis preoperatively retained it at the same level after surgery. All patients who could give a subjective response (eight of ten) reported more comfortable vision after surgery. No patient had more than minimal reduction of versions or ductions postoperatively and no other complaints or complications related to surgery have been noted to date. Follow-up was from 2 months to 31 months, excluding patient 6, who was lost to follow-up after I month.

DISCUSSION Nystagmus can be the cause of poor vision, as in the case of congenital motor nystagmus and in acquired nystagmus after neurologic insult. 5 Decreased foveation time and image movement are presumably the factors responsible for reduced vision. In these types of nystagmus, any strategy to reduce or stop eye movement will increase foveation time, reduce movement of the image on the retina, and, therefore, improve vision. This is why many patients assume a specific head posture to arrive at a null or neutral point for their nystagmus. Convergence is another strategy that results in improved vision. However, vision can improve during convergence with or without dampening of the nystagmus as shown by von Noorden and La Roche. 9 Surgery for nystagmus that is dampened by anomalous head posture (ocular torticollis) was proposed independently in the same year by Kestenbaum and by Anderson. 3,4 Both described an extraocular muscle procedure to achieve a null point with a more normal head posture (i.e., straight ahead or nearly so). This was accomplished with Kestenbaum's technique by carrying out recession and resection of yoke muscles of an equal amount. For example, with null point of nystagmus in right gaze accompanied by left head turn, both the right lateral and left medial recti were recessed 5 mm and the right medial and left lateral rectus were resected 5 mm. Anderson's scheme used equal yoke muscle recessions without resections of the remaining horizontal recti. Parks used a 5-, 6-, 7-, 8-mm and later a 6.5-, 8-, 9-, to-mm scheme for recession and resection to achieve larger effect. 10 Calhoun and Harley!! also advocated larger numbers for recession and resection and Cooper and Sandall!2 suggested a modified recession/resection plan by doubling the degree of face turn, converting this number to PO, and performing the appropriate amount of surgery. Vertical null point nystagmus with chin up or chin down can be treated with vertical muscle recession/resection starting with recession 1303

OPHTHALMOLOGY



AUGUST 1991



VOLUME 98



NUMBER 8

Table 1. Preoperative and Postoperative Results

Patient No.

Age (yrs)

Diagnosis

Surgery in mm from Limbus

Predominant Nystagmus Type

6

CMN

Pendular rapid

2

14

CMN

Pendular rapid

3

8

ONH

Pendular rapid

4

51

Albinism

Pendular rapid

5

14

CMN

Pendular rapid

6

31

CMN

Pendular rapid

7

31

ONH

Pendular rapid

8

1%

CMN

Pendular rapid

9

2%

Albinism

Pendular rapid

CMN

Pendular rapid

10

21

CMN = congenital motor nystagmus; MR up; XT = extropia; F&F = fix and follow.

=

MR 11.5 LR 11.0 MR 14.0 LR 18.0 MR 14.0 LR 16.0 MR 12.0 LR 11.0 MR 14.0 LR 17.0 MR 16.0 LR 16.0 MR 16.0 LR 16.0 MR 14.0 LR 12.0 MR 14.0 LR 14.0 MR 14.0 LR 14.0

medial rectus; LR

Preoperative Visual Acuity Distance, Near

Ocular Alignment (Preoperative/ Postoperative)

Head Posture (Preoperative/ Postoperative)

Change in Nystagmus

Follow-up (mas)

20/50, 20/40

20/40, 20/40

45 ETf10 ET

0/0

Nt

31

20/80, 20/50

20/60, 20/30

0/0

0/0

Nt

22

20/160, 20/125

20/100, 20/30

25 ET/O

0/0

Nt

14

20/160,20/100

20/100, 20/100

45 ET/25 ET

0/0

Nt

10

20/50, 20/30

20/30, 20/20

0/0

45° /20°

Nt

9

20/40, 20/40

20/40, 20/40

0/0

30 /WO

0

LTF

20/100, 20/30

20/70, 20/30

25 XT/5 XT

15° /15°

Nt

4

F & F, F & F

F & F, F & F

30 ET/5

0/0

Nt

3

F & F, F & F

F & F, F & F

20 ET/O

20 0 /WO

N ..

2

20/30, 20/30

20/30, 20/20

0/0

30°/30°

0

2

=

lateral rectus; ET

of the inferior rectus if the null is chin up and recession of the superior rectus if the null is in chin down as advocated by Parks.1O Recession of the inferior recti can produce an A pattern and lower lid lag. The inferior recti should be shifted medially to avoid the A pattern and careful dissection should be carried out, freeing the inferior rectus from Lockwood's ligament to avoid lid lag. In nystagmus blockage syndrome, convergence is used to dampen nystagmusY This produces a variable angle esotropia. Nystagmus blockage syndrome appears to be a type of null point strategy with secondary esotropia rather than being a primary esotropia. Nystagmus blockage syndrome is treated with bimedial rectus recession with or without Faden, or in some cases a Faden operation alone. Simultaneous "weakening" of antagonist horizontal muscles to reduce eye movement was suggested by Arruga l4 in cases of postoperative retinal detachment. He suggested placing a posterior fixation suture on the four horizontal recti. Bietti and Bagolini, 6 Limon and Bernadeli,? and von Noorden and Sprunger8 have all described weakening of the four rectus muscles to dampen nystagmus. von Noorden and Sprunger8 reported a case of manifest nystagmus in a 16-year-old patient with oculocutaneous albinism who underwent recession of all four horizontal rectus muscles of 10 mm (measured from the insertion), resulting in visual acuity improvement in the distance from preoperative values of 6/60 in the right eye and 6/30 in the left, and 6/15 near to postoperative values of 6/30 in the right eye and 6/21 in the left, and 6/12 near. Electronystagmography showed reduced nystagmus in all gaze positions when preoperative tracings were compared with postoperative tracings. Functional subjective vision was improved to an even greater degree than 1304

Postoperative Visual Acuity Distance, Near

=

estropia; N = nystagmus; ONH

0

=

optic nerve hypoplasia; LTF

=

lost to follow-

Snellen acuity results. Only a minimal reduction of ductions was noted in this patient despite the large recessions. Horizontal, vertical, and oblique axis nystagmus with oscillopsia can result from brain stem infarction. This has been treated successfully by us with retrobulbar injection of 25 units of botulinum A toxin. 5 This treatment produced dampening of the nystagmus and improvement of visual acuity from 20/100 to 20/30 in two cases. However the beneficial effect of botulinum toxin A (Oculinum, AIlergan) in these patients wore off gradually in 3 to 4 months and necessitated repeated injections. It is noteworthy that, in two patients treated by us who received a total of 13 injections between them, neither experienced ptosis as a result of the treatment. A third patient with nystagmus from brain stem contusion had complete ptosis after retrobulbar injection of25 units of botulinum toxin A. In this patient, as the ptosis resolved the nystagmus returned. Therefore, the patient received no benefit from this treatment. The precise mechanism responsible for dampening nystagmus in the retroequatorial horizontal muscle recession for the treatment of nystagmus is not known. Is the nystagmus slowed because of the muscle slack produced by the large retroplacement? Is the nystagmus slowed because the lever arm of the muscle action is reduced? These basic questions remain unresolved here as they do in the more straightforward arena of recession/resection strabismus surgery intended to change alignment. In the present series, patients who received maximum recession had very slight limitation of both abduction and adduction. This was not clinically significant. All patients had the same or improved Snellen acuity. The average visual improvement was modest at one line, but all patients reported more comfortable vision after surgery. The

HELVESTON et al



RECESSION OF THE HORIZONTAL RECTI

latter must be interpreted cautiously because the nystagmus patient is highly motivated to achieve better vision to enhance their quality of life. Two patients underwent surgery with the specific aim of meeting the visual requirements for obtaining a driver's license. Both of these patients whose vision improved slightly subsequently enrolled in a driver's training class at a facility that specializes in preparing the visually impaired for taking the stateadministered driver's test. One patient received a limited license and one patient continues the training. Objective and subjective visual improvement was noted both in patients who had purely motor nystagmus and those with nystagmus associated with oculocutaneous albinism and optic nerve hypoplasia. Evaluation of these ten patients indicates that four muscle retroequatorial recession is a safe and moderately effective procedure at least in the short term. The surgery produced objective and/or subjective vision improvement in the early postoperative period, more comfortable vision with no induced strabismus, no loss of fusion, and no significant limitation of motility. In contrast to the Kestenbaum-Anderson procedure, which uses resection of two horizontal rectus muscles, four muscle recession is tissue sparing and is potentially reversible. Modification of the four muscle recession technique to treat concurrent esotropia and nystagmus when indicated was successful in the patients treated. This procedure has been shown to be effective on a mechanical basis when eye muscle attachment is healed by 2 months. Further evaluation and long-term follow-up of possible sensory and oculomotor factors is necessary to establish the ultimate value of this technique.

REFERENCES 1. Burde RM, Savino PJ, Trobe JD. Clinical Decisions in Neuro·oph· thalmology. St. Louis: CV Mosby, 1985; 200-1. 2. Dell'Osso LF. Improving visual acuity in congenital nystagmus. In: Smith JL, Glaser JS eds. Neuro·ophthalmology. Vol. 7. St Louis: CV Mosby, 1973; 98-106. 3. Anderson JR. Causes and treatment of congenital eccentric nystag· mus. Br J Ophthalmol1953; 37:267-81. 4. Kestenbaum. Periodisch umschlagender Nystagmus. Klin Monatsbl Augenheilkd 1930; 84:552. 5. Helveston EM, Pogrebniak AE . Treatment of acquired nystagmus with botulinum A toxin. Am J Ophthalmol1988; 106:584-6. 6. Bietti GB, Bagolini B. Traitement medicochirurgical du nystagmus. Annee Ther Clin Ophtalmol 1960; 11 :269-96. 7. de Brown E Limon, Bemadeli J Corvera. Metodo debilitante para el tratamiento del Nistagmus. Rev Mex Oftalm Marzo-Abril 1989; 63:65-

7. 8. von Noorden GK, Sprunger DT. Large rectus muscle recessions for the treatment of congenital nystagmus. Arch Ophthalmol 1991; 109: 221-4. 9. von Noorden GK, La Roche R. Visual acuity and motor characteristics in congenital nystagmus. Am J Ophthalmol1983; 95:748-51. 10. Parks MM. Congenital nystagmus surgery. Am Orthopt J 1973; 23: 35-9. 11. Calhoun JH, Harley RD. Surgery for abnormal head position in congenital nystagmus. Trans Am Ophthalmol Soc 1973; 71:70-87. 12. Cooper EL, Sandall GS. Surgical treatment of congenital nystagmus. Arch Ophthalmol1969; 81 :473-80. 13. von Noorden GK, Wong SY. Surgical results in nystagmus blockage syndrome. Ophthalmology 1986; 93:1028-31. 14. Arruga A. Posterior suture of rectus muscles in retinal detachment with nystagmus: a preliminary report. J Pediatr Ophthalmol 1974; 11 : 36-7.

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Large recession of the horizontal recti for treatment of nystagmus.

Ten patients had large recession of four horizontal recti at one procedure for treatment of nystagmus. Six patients had congenital motor nystagmus, tw...
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