Dr.Sathya T Ravilla, Dr.Shashikant Shetty,Dr.Vijayalakshmi P
Introduction
Aberrant regeneration is seen frequently due to misdirected innervation in recovering third nerve palsy of traumatic etiology. The misrouting of fibres cause several synkinetic phenomena such as eyelid retraction with adduction or pupillary miosis with elevation, adduction or depression.Pseudo-von-Graefe’s sign, inverse Duane’s sign, Pseudo Argyll-Robertson are some of the features seen. Surgical management usually involves two staged procedures and is complex owing the high chance of recurrence of the exotropia and poor Bell’s phenomenon.
Conventional Surgery:
Surgery is planned when a third nerve palsy does not resolve by six months. Conventionally, surgery is usually done as a two staged procedure. The strabismus is tackled first followed by ptosis surgery.
For strabismus, supramaximal medial rectus resection and Lateral rectus recession is done in the ipsilateral eye. The disadvantage of this procedure is that we are strengthening a muscle with paresis. Hence the effect of surgery will wean over time and the eye will become exotropic again. Secondarily, the LR muscle undergoes chronic contracture as the resected muscle elongates.
The synkinetic ptosis is addressed by disinserting the levator andfrontalis suspension in the affected eye. The disadvantage of this procedure is the risk of corneal exposure because of limitation of extraocular movements and poor Bell’s phenomenon
Principle of surgery in contralateral eye
Performing a recess-resect procedure on the contralateral fixing eye forces it into an adducted position. Due to Hering’s law of equal innervation of yoke muscles, fixation duress is created on the affected eye medial rectus muscle, pulling it into an adducted position when the fixing eye assumes fixation. Thereby, the ptotic lid is elevated and the need for ptosis surgery obviated.
Case Series
Our first patient was a 48 years old ladypseudophakic in both eyes. She had a best corrected vision of 6/9 in her right eye, and 6/6 in her left eye. She had sustained head trauma in an accident 2 years ago. She complained of drooping of her right upper lid following the trauma. She perceived binocular diplopia for the past year after there was slight improvement in the ptosis.
On evaluation, she had a central vertical palpebral fissure width of 5 mm in her right eye. She had a primary deviation of 25 PD XT with 8 PD L/R for distance and 35 PD XT with 3 PD L/R for near. The secondary deviation (with right eye fixation) was 35 PD XT with 14 PD L/R for distance and 45 XT with 8 PD L/R for near. She was able to fuse with 25 PD BI and 6 PD BU.
As we were operating on the contralateral eye, surgery was planned for the secondary deviation. 7mm LR recession with 5.5 mm LR resection with 2.5 mm downward displacement was done in her left eye. The Lateral rectus was placed on an adjustable suture and was pushed back by 2 mm on the next day as there was a 8PD exotropia on the first post op day.
Patient was diplopia free postoperatively and there was a significant improvement in the ptosis in the primary position. At one month post operatively, the vertical palpebral fissure had improved from 5 to 8 mm. The deviation was 6 PD XP with 8 PD L/R for distance and 8 PD XP with 4 PD L/R for near.
The other two patients also had third nerve palsy of traumatic etiology in the right eye and showed significant improvement in ptosis and strabismus post-operatively.
| Case Series No | Pre-Op Central palpebral fissure width | Pre-Op Central palpebral fissure width | Pre-Operative secondary deviation for distance | Post operative deviation for distance | Surgical correction |
| 1 | 5 mm | 8 mm | 35 PD XT with 14 PD L/R | 6 PD XP with 8 PD L/R | 7mm LR recession with 5.5 mm LR resection with 2.5 mm downward displacement |
| 2 | 4 mm | 8 mm | 25 PD XT with 12 PD L/R | 4 PD XP | 6mm LR recession with 4.5 mm MR resection
with 5 mm downward displacement |
| 3 | 5 mm | 8 mm | 35 PD XT with 6 PD L/R | Orthotropic | LE 8 mm LR recession with 5 mm MR resection |
Conclusion
Aberrant 3rd nerve regeneration is a complex entity to manage owing to presence of ptosis, exotropia and hypotropia concurrently. Operating on the ipsilateral eye would mean multiple procedures to correct the ptosis and strabismus
Contralateral eye surgery utilizing innervation principles allows us to simultaneously address both problems with predictable and fairly accurate outcomes in a single sitting. Thorough pre-operative evaluation and patient counselling is required
References
- Thanh Nguyen PT, Tibrewal S, Ganesh S. Contralateral eye surgery with adjustable suture for management of third nerve palsy with aberrant regeneration. Indian J Ophthalmol 2017;65:1058-61.
- Boghen D, Chartrand JP, Laflamme P, Kirkham T, Hardy J, Aube M. Primary aberrant third nerve regeneration. Ann Neurol1979;6:415-418.
- Parulekar MV, Elston JS. Surgery on the Nonparetic Eye for Oculomotor Palsy With Aberrant Regeneration. JPOS 2003;40:219-221.
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