Transposition surgery is a procedure that changes the course of extraocular muscles to improve eye misalignment or restricted eye movement caused by palsy or dysfunction.
Since Hummelsheim reported the first transposition surgery for abducens nerve palsy in 1908 1), many modified techniques have been developed. There are various variations such as the Jensen method, and minimally invasive techniques like the Nishida method, which achieve equivalent effects without resecting nutrient vessels, have also been developed.
It is contraindicated in patients with impaired blood flow or significant vascular risk, or when there is restriction of the antagonist muscle.
Main indications include paralytic strabismus (abducens nerve palsy, oculomotor nerve palsy), Duane syndrome (when compensatory head posture or horizontal deviation is marked), monocular elevation deficiency, and lost or slipped muscles. It is selected when there is severe limitation of eye movement that cannot be addressed by conventional recession-resection procedures.
The main diseases for which transposition surgery is indicated are listed below.
Paralytic Strabismus
Abducens nerve palsy: The most common indication. Acquired causes include trauma, cerebrovascular disease, brain tumor, peripheral neuropathy, viral infection, and diabetes.
Oculomotor nerve palsy: Superior oblique tendon transfer (Scott procedure) or nasal transposition of the lateral rectus muscle is indicated.
Other Indications
Duane retraction syndrome (DRS): Compensatory head posture, horizontal deviation, and severe co-contraction are surgical indications.
Monocular elevation deficiency (MED/double elevator palsy): Modified Nishida procedure is used.
Lost or slipped muscle: Transposition is chosen when conventional reattachment is not possible.
Fixed esotropia associated with high myopia: The superior and lateral rectus union procedure (Yokoyama method) is effective.
If the eye can move to the front in incomplete palsy, anteroposterior transposition (shortening of the paretic muscle plus recession of the antagonist) can be used. For incomplete palsy that does not cross the midline or complete palsy, muscle transposition is necessary.
If the eye moves beyond the midline in incomplete palsy, it can be managed with anteroposterior transposition (shortening of the paretic muscle + recession of the antagonist muscle). Muscle transposition is indicated only for incomplete palsy that does not cross the midline or complete palsy. In principle, conservative observation is performed for 6 months after onset to wait for spontaneous recovery.
| Examination | Purpose |
|---|---|
| Cover test | Assessment of deviation magnitude and direction |
| Hess chart | Visualization of movement disorder patterns of each extraocular muscle |
| Forced duction test | Presence of restriction (if restriction exists, transposition surgery is contraindicated) |
| Active force generation test | Assessment of residual function of the affected muscle |
| Prism measurement | Quantification of deviation (PD) |
| Head imaging (CT/MRI) | Search for lesions in brainstem, skull base, cavernous sinus, and orbit |
| MRI T1 coronal view | Assessment of superior oblique muscle atrophy (differential diagnosis of decompensation) |
The traction test is an essential preoperative examination because if restriction is present, the patient is not eligible for transposition surgery.
In principle, surgical indication is determined after a 6-month period of conservative observation.
Full tendon transposition (FTT)
The full width of the superior and inferior rectus muscles is transposed to the lateral rectus side. Simultaneous surgery on the horizontal rectus muscles should be avoided to prevent anterior segment ischemia.
Augmentation: Addition of shortening of the superior and inferior rectus muscles before transposition, adjustable sutures, and posterior fixation sutures (6–8 mm posterior to the lateral rectus insertion).
Hummelsheim procedure
Move half the width of the superior and inferior rectus tendons. This preserves half of the ciliary vessels, reducing the risk of anterior segment ischemia.
Modified type: Add medial rectus recession, transposed muscle tendon shortening, and posterior fixation suture. Reported as preoperative 43PD±5PD → postoperative 6PD±7PD.
Augmented type: Effective for paralytic esotropia. X-type transposition is effective for exotropia1).
Anterior segment ischemia is the most important complication, with risk increasing when three or more rectus muscles are operated on. Half-tendon transposition procedures such as the Hummelsheim and Jensen methods reduce this risk by preserving part of the ciliary vessels. The Nishida procedure does not require tenotomy and can further preserve nutrient vessels. Additionally, complete improvement of eye movement cannot be expected postoperatively, and diplopia may persist in positions other than primary gaze.
The mechanism of action of transposition surgery involves multiple factors.
It is likely that multiple mechanisms contribute simultaneously.
The main purpose of transposition surgery is to align the eyes in primary position. Monocular movement in the direction of the paralyzed muscle may not improve significantly.
The main purpose of transposition surgery is to correct eye alignment in primary position (straight ahead) and eliminate compensatory head posture. Improvement in monocular movement toward the paralyzed muscle may be limited, and diplopia may persist in directions other than primary position. However, if diplopia is eliminated in primary position and downgaze, quality of daily life can be greatly improved.
Sheng et al. (2024) reported that for supranuclear ophthalmoplegia persisting for 8 years due to a brainstem cavernous hemangioma, two-stage surgery (Stage 1: right medial rectus and lateral rectus recession 10 mm; Stage 2: right lateral rectus resection 10 mm + left medial rectus resection 8 mm + right superior and inferior rectus half-tendon transposition) achieved good primary position alignment and resolution of compensatory head posture1). No anterior segment ischemia was observed at 6 months postoperatively.
In a long-term follow-up of 22 cases by Jethani, combined muscle transposition and shortening/recession of the medial and lateral rectus muscles for large-angle esotropia exceeding 85 PD maintained good correction over an average follow-up of 2 years1).
In the report by Arfeen et al., no statistically significant difference in success rate was found between the Hummelsheim procedure and the Jensen procedure for chronic abducens nerve palsy1).
In the report by Gokoffski et al., the augmented Hummelsheim procedure was effective for paralytic esotropia, while the X-type transposition procedure was effective for exotropia1).
