Dr.Muralidhar Rajamani, R10440
Abstract:
Context: The augmented Anderson Procedure has been reported to correct face turns in Infantile Nystagmus Syndrome from 15-40 degrees. It has been our experience that there it is not very effective for face turns over 20 degrees. (references) We propose augmenting the procedure with resections for larger face turns.
Aims:To describe the outcome of augmenting the Augmented Anderson Procedure by adding 5mm of medial rectus resection and 7mm of lateral rectus resection
Settings and Design: Retrospective Non-randomized interventional study
Methods and Material: We added 5mm of MR resection and 7mm of LR resection to the augmented Anderson procedure for face turns > 20 degrees. Records of patients who had undergone surgery from January 2014 to March 2017 and completed 3 months of follow up were retrieved and patient characteristics noted.
Results: Six patients with infantile nystagmus and face turns > 20 degrees were included. The mean age was 17.7 years (6-24). Mean preoperative face turn was 29.2 degrees. At 3 months, 3 patients had no face turn, 2 had residual face turn of 5 degree and 1 had consecutive face turn of 5 degree (mean 0.83). No patient had induced strabismus. The maximum extraocular movement restriction was 2- in the direction of the recessed muscles.
Conclusions: Augmentation of the augmented Anderson procedure is effective for large face turns in INS
Key-words:Augmentation, augmented Anderson Procedure, Infantile Nystagmus
Key Messages:Augmentation of the Augmented Anderson Procedure may be considered for large face turns in Infantile Nystagmus syndrome
Introduction:
Most patients with infantile nystagmus have a null zone where the nystagmus amplitude and frequency is the least. When the null zone coincides with the primary gaze, the patient may not have any head posture. Often however the null zone is located in an eccentric gaze position causing the patient to assume a head posture. Extraocular muscle surgery for these patients is performed to move the null zone to the primary position. A number of surgical procedures have been described. Anderson advocated only recessions, and Goto advocated resections. Kestenbaum advocated recession, resection of all the four horizontal recti. Park’s described the classic maximum (5,6,7,8 such that the total surgery performed in each eye is 13mm). Augmentations of this procedure have been described for large face turns. It should be noted that large recessions and resections can produce incomitance. Gupta et al (4)described the augmented Anderson procedure for anomalous face turns more than 15 degrees and noted an improvement in the head posture, primary position visual acuity, ETDRS visual acuity and stereopsis with only a small restriction in extraocular motility produced by the procedure. There was also an improvement in nystagmus frequency and amplitude. The face turns in the study varied from 25 to 40 degrees. At 3 months, 6 out of 12 patients had a substantial residual face turn, though all patients had an improvement. It has been the author’s personal experience that the augmented Anderson’s procedure results in a residual head posture when the face turn is more than 20 degrees. Hence we propose adding a medial rectus (MR) resection of 5mm and a lateral rectus resection (LR) of 7mm for larger face turns.
Subjects and Methods:
The records of all patients who underwent augmentation of the augmented Anderson Procedure from January 2014 to March 2017 and completed 3 months of follow up were retrieved from the Electronic Medical Records of the hospital. The study adhered to the tenets of the Declaration of Helsinki. Patients older than 5 years of age, who had a diagnosis of infantile nystagmus syndrome with face turns of over 20 degrees, were included for the study.Patients with conditions like cerebral palsy, intellectual impairment that could hamper measurement of nystagmus characteristics were excluded. Patients who had undergone resection of any horizontal rectus muscle, had a consecutive face turn after previous nystagmus surgery or had previous strabismus surgery which precluded surgery on four horizontal recti were also excluded.
All patients underwent a complete ophthalmic examination including estimation of visual acuity, refraction and cycloplegic refraction, and a comprehensive ophthalmic examination. A note was made of past nystagmus/strabismus surgeries if any. All patients wore their refractive correction during the time of the exam and were counselled for nystagmus surgery only after completing amblyopia therapy (when applicable). Characteristics of nystagmus like direction, amplitude, frequency, type, dampening on convergence, null zone and symmetry was noted. The anomalous head posture was assessed on at least 2 occasions with observation periods of over 8 minutes each with a distance fixation chart that was repeatedly changed during examination to prevent the patient from memorizing the chart. Measurement of the head posture was done with a cephalodeviometer and also with prisms (apex oriented towards the direction of gaze and placed over each eye) A cover test was done for distance and near to record any strabismus and the angle measured with prisms when applicable. The binocular visual acuity was recorded in primary position, null position, right and left gaze. Binocularity was assessed with Bagolini striated glasses and stereoacuity was recorded with Randotstereotest.
All surgeries were done by a single surgeon (the author) by a limbal incision. The surgery involved adding 5mm of MR resection and 7mm of LR resection to the Augmented Anderson procedure. For example if a patient had 30 degrees of right face turn, the left LR was recessed by 12.0mm, the left MR was resected by 5.0mm, the right MR was recessed by 9.0mm and the right LR was resected by 7.0mm. For patients with previously recessed horizontal recti, the measurements for further recession were taken from the limbus. After surgery patients were treated with a tapering dose of topical steroid antibiotic combination for ten days and lubricants for six weeks. Surgeries were done under general anaesthesia with endotracheal intubation for patients younger than 16 years of age. For older patients, surgery was done under intravenous sedation with fentanyl and midazolam.
Patients were reviewed on the first postoperative day, first month and third month. At each visit, the binocular visual acuity in primary position, right and left gaze was recorded. The head posture, and strabismus if any for distance and near was recorded. Ocular motility restriction was noted. All patients also underwent slit lamp and fundus examination at each of these visits. In addition a note was made of the nystagmus characteristics at the 1st and 3rd months.
Results:
A total of six patients with infantile nystagmussyndrome were included. Two of these patients had undergone 6.0mm recession of the medial rectus in one eye and 9.0mm lateral rectus in the other eye. The mean age was 17.7 years +/- SD (range 6-24 years). Patient characteristics are mentioned in table 1 included at the end of the manuscript. The mean preoperative face turn was 29.2 degrees (range 25-35 degrees). Three patients had associated strabismus and suitable adjustments were made in the surgical dosage for recessions in two patients.
All patients had an improvement in head posture evident at the first postoperative day. The mean correction achieved was 28.3 degrees (range 25-30 degrees). Three patients had complete resolution of horizontal face turn and one patient had a consecutive face turn. Two patients had a residual face turn of five degrees, but this persisted in only patient at the final review. No patient had a residual/consecutive face turn > 5 degree. All patients had substantial improvement in primary position visual acuity (p=0.004). The face turn at one month did not substantially differ from the face turn at the final review. The mean follow up was 7.5 months (range 3-12 months).
Ocular motility on the side of the recessed muscle was noted in all patients but was 2- in only two patients. The remaining had mild ocular motility restriction of 1-. All patients had some improvement in stereopsis, but this was not statistically significant. No patient had an induced strabismus. The three patients with strabismus had an improvement in primary position deviation.
Discussion:
The study shows that augmentation of the Augmented Anderson Procedure is an effective procedure to treat large face turns in infantile nystagmus syndrome. Accompanying strabismus can be corrected to some extent by tweaking the surgical dosage. Gupta et al (4) reported that the Augmented Anderson procedure is effective in correcting face turns from 25-40 degrees, but six of the twelve patients reported in his study had residual face turns ranging from 10-20 degrees. The visual acuity in primary position and stereopsis improved in our patients which is in agreement with Gupta et al’s study. Adding a resection did not restrict motility beyond 2-. None of our patients had an induced strabismus.
The limitations of our study include small number of patients. Another limitation is that ocular motility recordings were not done due to lack of equipment. Further studies with larger number of patients need to be done before this approach can be recommended for general use in infantile nystagmus syndrome with large face turns.
References:
- Anderson JR. Causes and treatment of congenital nystagmus Br JOphthalmol 1953;37:267-81.
- Goto N. A study of optic nystagmus by electrooculogram. ActaSocOphthalmolJpn 1954;58:851-5.
- Kestenbaum A. A nystagmus operation. Bull SocOphthalmol 1953;6:599-602.
- Gupta R, Sharma P, Menon V.A prospective clinical evaluation of augmented Anderson procedure for idiopathic infantile nystagmus.J AAPOS. 2006 Aug;10(4):312-7.
- Parks MM. Congenital nystagmus surgery. Am Orthoptic J 1973;23:35-9.
Table 1: Patient Characteristics
| Serial No. | Age | M/F | Diagnosis | Preop Face turn | Preop Strabismus | Previous nystagmus surgery | Surgery | Anaesthesia | Face turn at one Month | Strabismus at one month | Follow up | Maximum Ocular motility restriction | Face turn at final review | Strabismus at final review |
| 1 | 16 | F | INS | 25L 15 degree chin elevation | 18 BI | 9/6 | 13/6, 9/7 BE PTSO | GA | 10 degree chin elevation | 12 BI, 8 r/l | 1 year | 2- | 10 degree chin elevation | 10 BI, 6 r/l |
| 2 | 24 | F | INS | 30L | 0 | nil | 12/5, 9/7 | S | 0 | 0 | 3 months | 1- | 0 | 0 |
| 3 | 23 | M | INS | 30R | 0 | nil | 12/5, 9/7 | S | 0 | 0 | 6 months | 2- | 0 | 0 |
| 4 | 23 | M | INS | 30L | 14 BO | nil | 11/5, 10/7 | S | 5L | 0 | 6 months | 1- | 5L | 0 |
| 5 | 6 | F | INS | 35R | 12 BI | nil | 12/5, 9/7 | GA | 5R | 14 BI | 1year | 1- | 0 | 12 BI |
| 6 | 14 | F | INS | 25L | 0 | 9/6 | 12/5, 9/7 | GA | 5R | 0 | 6 months | 1- | 5R | 0 |
F- female
M- male
INS- infantile nystagmus syndrome
L- left, R- right
BO- base out
BI- base in
9/6-9mm lateral rectus recession with other eye 6mm medial rectus recession for nystagmus
12/5, 9/7- 12 mm LR recession with 5mm MR resection and other eye 9mm MR recession with 7mm LR resection
PTSO – posterior tenectomy of the superior oblique
BE- both eyes
GA- general anaesthesia
S- sedation
Leave a Comment