[Indication and Results of the Anderson Procedure]

[Nystagmus in Children - a Survey]

Nystagmus describes an involuntary, periodic movement of one or both eyes. About 1/600 children and adolescents have nystagmus, most of them idiopathic infantile nystagmus (IIN), also called "congenital nystagmus", which can be caused by mutations in the FRMD7 gene. Other frequent forms of nystagmus are latent nystagmus, which is usually associated with infantile strabismus, and nystagmus associated with albinism. Sometimes difficult to distinguish in young infants is a sensory nystagmus, where a defect in the visual system reduces vision and causes nystagmus. Causes include retinal dystrophies, congenital stationary night blindness and structural ocular defects including optic nerve hypoplasia or dense bilateral congenital cataracts. Unilateral nystagmus can be the sign of an anterior visual pathway lesion. Seesaw nystagmus may be associated with suprasellar and mesodiencephalic lesions and - rarely - with retinal dystrophies.The ophthalmology plays a key role in identifying the form of nystagmus. Children with new onset nystagmus, with spasmus nutans, with vertical or unilateral nystagmus and those with seesaw nystagmus require neurologic evaluation including imaging of the brain.The treatment of nystagmus depends on the underlying cause. Even minor refractive errors should be corrected, contact lenses offer advantages over glasses.Gabapentin and memantine, possibly also carbonic anhydrase inhibitors, are effective in treating IIN, nystagmus in albinism and sensory nystagmus. Nevertheless, pharmacologic treatment of nystagmus is rarely used in children; the reasons are the limited effects on vision, the need for lifelong therapy, and potential side effects. Eye muscle surgery (Anderson procedure, Kestenbaum procedure) can correct a nystagmus-related anomalous head posture. The concept of "artifical divergence" of Cüppers may help to decrease nystagmus intensity in patients whose nystagmus dampens with convergence. The four-muscle-tenotomy, which involves disinsertion and reinsertion of the horizontal muscles at the original insertion of both eyes, has a proven but limited positive effect on visual acuity.

Nystagmus bei Kindern – eine Übersicht

Nystagmus ist definiert als unwillkürliche, periodische Bewegung, bei der eines oder beide Augen vom Fixationspunkt wegdriften (sog. Drift). Auf die Drift, die langsame Phase, folgt entweder eine schnelle, refixierende Bewegung (sog. Refixationssakkade oder schnelle Phase) oder eine langsamere Bewegung zur Wiederaufnahme der Fixation. In dieser Übersichtsarbeit sollen die wichtigsten Formen von Nystagmus bei Kindern erörtert werden, für eine Übersicht bei Erwachsenen sei auf 1 verwiesen.

Surgical interventions for infantile nystagmus syndrome

BACKGROUND

Infantile nystagmus syndrome (INS) is a type of eye movement disorder that can negatively impact vision. Currently, INS cannot be cured, but its effects can potentially be treated pharmacologically, optically, or surgically. This review focuses on the surgical interventions for INS. Despite the range of surgical interventions available, and currently applied in practice for the management of INS, there is no clear consensus, and no accepted clinical guidelines regarding the relative efficacy and safety of the various treatment options. A better understanding of these surgical options, along with their associated side effects, will assist clinicians in evidence-based decision-making in relation to the management of INS.

OBJECTIVES

To assess the efficacy and safety of surgical interventions for INS.

SEARCH METHODS

We searched CENTRAL, MEDLINE Ovid, Embase Ovid, ISRCTN registry, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) to 3 July 2020, with no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) studying the efficacy and safety of surgical options for treating INS.

DATA COLLECTION AND ANALYSIS

Our prespecified outcome measures were the change from baseline in: binocular best-corrected distance visual acuity; head posture; amplitude, frequency, intensity, and foveation period durations of the nystagmus waveform; visual recognition times; quality of life and self-reported outcome measures; incidence of adverse effects with a probable causal link to treatment; and permanent adverse effects after surgery. Two review authors independently screened titles and abstracts and full-text articles, extracted data from eligible RCTs, and judged the risk of bias using the Cochrane tool. We reached consensus on any disagreements by discussion. We summarised the overall certainty of the evidence using the GRADE approach.

MAIN RESULTS

We only identified one eligible RCT (N = 10 participants), undertaken in India. This trial randomised participants to receive either a large retro-equatorial recession of the horizontal rectus muscle of 9 mm on the medial rectus and 12 mm on the lateral rectus, or a simple tenotomy and resuturing of the four horizontal rectus muscles. We did not identify any RCTs comparing a surgical intervention for INS relative to no treatment. In the single eligible RCT, both eyes of each participant received the same intervention. The participants' age and gender were not reported, nor was information on whether participants were idiopathic or had sensory disorders. The study only included participants with null in primary position and did not explicitly exclude those with congenital periodic alternating nystagmus. The study did not report funding source(s) or author declaration of interests. The evaluation period was six months. We judged this study at low risk for sequence generation and other sources of bias, but at high risk of bias for performance and detection bias. The risk of bias was unclear for selection bias, attrition bias, and reporting bias. There is very uncertain evidence about the effect of the interventions on visual acuity and change in amplitude, frequency, and intensity of the nystagmus waveform. We were unable to calculate relative effects due to lack of data. None of the participants in either intervention group reported adverse effects at six-month follow-up (very low-certainty evidence). There was no quantitative data reported for quality of life, although the study reported an improvement in quality of life after surgery in both intervention groups (very low-certainty evidence). Change in head posture, foveation period durations of the nystagmus waveform, visual recognition times, and permanent adverse effects after surgery were not reported in the included study. We judged the certainty of the evidence, for both the primary and secondary efficacy outcomes, to be very low. Due to a lack of comprehensive reporting of adverse events, there was also very low-certainty of the safety profile of the evaluated surgical interventions in this population. As such, we are very uncertain about the relative efficacy and safety of these interventions for the surgical management of INS.

AUTHORS' CONCLUSIONS

This systematic review identified minimal high-quality evidence relating to the efficacy and safety of surgical interventions for INS. The limited availability of evidence must be considered by clinicians when treating INS, particularly given these procedures are irreversible and often performed on children. More high-quality RCTs are needed to better understand the efficacy and safety profile of surgical interventions for INS. This will assist clinicians, people with INS, and their parents or caregivers to make evidence-based treatment decisions.

[Highly dosed Anderson and Kestenbaum operations for anomalous head posture due to nystagmus]

Hintergrund

Die Korrektur einer Kopfzwangshaltung (KZH) bei infantilem Nystagmussyndrom (INS) erfolgt mit der Kestenbaum-Operation (KO) in Form der beidseitigen Rücklagerung der in KZH aktiven Agonisten und Verkürzung ihrer Antagonisten oder mit der Anderson-Operation (AO) durch die alleinige Rücklagerung der Agonisten.

Ziel der Arbeit

Vergleich der Ergebnisse hoch dosierter AO und KO bei ähnlicher KZH.

Patienten und Methoden

In unterschiedlichen Zeiträumen (2013 bis 2019 bzw. 2003 bis 2013) kam ausschließlich die AO bzw. die KO zur Anwendung. Eine hoch dosierte AO erhielten in einer konsekutiven Fallserie 33 Orthotrope mit INS und KZH, eine KO erhielten 19 Patienten. Die Mediane und Streubreiten (min–max) in den Gruppen AO/KO betrugen: Alter bei OP 7 (4–44) Jahre/6 (4–27) Jahre; KZH 32,5°(20–45)/30°(17–40); Operationsstrecke pro Auge AO 13 (10–16) mm (Standarddosis), KO 10 (6–12) mm + 10 (6–12) mm (Mittel 0,60 mm/°KZH).

Ergebnisse

Die KZH betrug nach ca. 3 Monaten 10°(−3–20)/10°(−7–20), bei der Spätkontrolle (8 bis 153 Monate) 10°(0–20)/10°(−27–30). Sie war bei der letzten Kontrolle um 67 % (20–100)/64 % (14–100) verringert. Eine Restdrehung ≤15° fand sich in 79/81 % der Fälle (91 % nach AO ≥13 mm; n = 23), ein Rest ≤10° in 55/57 %, (65 % nach AO ≥13 mm). Die Ad‑/Abduktionsfähigkeit der rückgelagerten Muskeln betrug nach AO 30°/30° (10–37/15–45), nach KO 32°/30° (10–40/12–45). Eine assoziierte Kopfneigung wurde durch den Eingriff nicht verbessert. Der mittlere Anstieg des binokularen Visus betrug jeweils <1 Zeile, in der Gruppe AO 1 Zeile bei Kindern ≤6 Jahre, kein Anstieg in der Altersklasse >6 Jahre.

Schlussfolgerung

AO und KO waren bei der verwendeten Dosierung wirkungsgleich. Die geringere Invasivität der AO spricht für deren Anwendung als Ersteingriff.

High-dose Anderson operation for nystagmus-related anomalous head turn

PURPOSE

To evaluate the effectiveness of a high-dose Anderson procedure (AP) to correct infantile nystagmus-related anomalous head turn (HT).

METHODS

Twenty-nine consecutive orthotropes with infantile nystagmus with and without associated sensory defect received high-dose AP. HT was measured while the patient tried to read letters at best-corrected visual acuity (BCVA) level at 5 m and 0.3 m. BCVA, binocular vision (BV), and alignment (prism and cover test) were measured. High-dose AP with recessions of 9-16 mm was performed. All measures were taken before and 3-6 and ≥ 8 months post surgery. Success was defined by postoperative HT ≤ 10°/HT ≤ 15°.

RESULTS

Medians and ranges (minimum-maximum) were:. Age at surgery was 7 years (4-44). HT at 5 m and HT at 0.3 m were 35° (20-40) and 20° (0-35), respectively. After 4 months (3-6), HT was 10° (- 3-20) and 5° (- 5-20); success rates were 74%/96% and 83%/96%. After 15 months (8-45), HT was 12° (0-20) and 6° (0-15); success rates were 46%/75% and 92%/100%; residual HT > 15° occurred in 5/9 cases with recessions < 13 mm and 1/15 cases with recessions ≥ 13 mm. With recessions ≥ 13 mm, 60% (95% confidence intervals (C.I.), 33-83%) achieved HT ≤ 10° and 93% (95% C.I. 66-99%) achieved HT ≤ 15°. Overcorrection did not occur. Anomalous head posture components in vertical and frontal planes did not improve. Residual motility was 30° (10-45). The mean BCVA improved by only 0.037 logMAR (p = 0.06). BV and ocular alignment were constant, except in 2 patients whose exophoria decompensated.

CONCLUSIONS

Kestenbaum surgery is a common procedure to correct infantile nystagmus-related HT. Anderson surgery is confined to bilateral yoke muscle recession; hence, less invasive but nevertheless comparably effective, high dosage is provided.