Surgical management of unilateral elevator deficiency associated with horizontal deviation using a modified Knapp's...

Area of Science:

• Ophthalmology
• Strabismus Surgery
• Oculoplastics

Background:

• Unilateral elevator deficiency presents challenges for correcting coexisting horizontal deviations.
• Standard surgical approaches often address vertical or horizontal deviations separately.

Purpose of the Study:

• To report an effective surgical method for simultaneous correction of vertical and horizontal deviations.
• To evaluate the outcomes of a modified Knapp's procedure in patients with unilateral elevator deficiency and horizontal deviation.

Main Methods:

• A modified Knapp's procedure involving transposition of medial and lateral recti was performed.
• The superior half of the recti muscles were used for vertical deviation correction, and the inferior half for horizontal deviation correction.
• Ten patients with type II unilateral elevator deficiency and significant horizontal deviation (18–45 PD) were included.

Main Results:

• The modified Knapp's procedure successfully corrected a mean of 20 PD horizontal deviation and 25 PD vertical deviation.
• No significant adverse effects were observed during the 21-month follow-up period.
• The procedure demonstrated efficacy in managing combined deviations.

Conclusions:

• A modified Knapp's procedure is a recommended surgical option for unilateral elevator deficiency with associated horizontal deviation.
• This technique offers a simultaneous and effective solution for complex strabismus.
• The procedure shows a favorable safety profile and good long-term outcomes.