FP1219 : Outcome of Tarsal Switch Procedure for Myopathic Ptosis with Poor Eye Protective Mechanisms

Dr. Sangeeta, S19441, Dr. Narendra Patidar, Dr. Animesh Sahu, Dr. Ram kishore shandilya

INTRODUCTION

The surgical management of myopathic ptosis in patients with poor eye protective mechanisms is challenging. Myopathies causing ptosis are often progressive, associated with fair to poor levator function resulting in significant visual obscuration. In patients with myopathic ptosis, ocular motility is often impaired, orbicularis muscle can be weak resulting in poor or absent Bell’s phenomenon^1,2 which increases the risk of postoperative lagophthalmos. As a result, these patients are often denied the benefit of ptosis correction for fear of creating corneal exposure problems.

Goal for ptosis correction in patients with poor eye protective mechanisms is to correct the ptosis appropriately without risk of iatrogenic complications. Simultaneous surgery to lift both the upper and lower eyelids has been shown to be effective in correcting ptosis while reducing the risk of corneal exposure. The original technique described levator advancement and resection and simultaneous recession of the lower eyelid using a scleral spacer or a graft harvested from ear cartilage or hard palate.³

The tarsal switch procedure limits surgery to the eyelids and avoids homografting and xenografting. The tarsal switch procedure predictably raises the upper eyelid in a predetermined amount and raises the lower eyelid approximately the same amount.

Materials and methods:

This is prospective interventional study of 14 eyelids of 9 patients assigned to undergo the tarsal switch levator resection procedure. Indications for surgery were moderate to severe myopathic ptosis, with reduced levator function, poor Bell’s response, and reduced eye ductions.

After taking ethical committee approval and fulfilling inclusion criteria informed consent was obtained from all patients. Patients demographics, surgical indications, preoperative examination (MRD1, MRD2, palpebral aperture height (PAH), LPS action ) were recorded and postoperative results (MRD1 ,MRD2, mean change in palpebral aperture height)  and complications, as well as  length of follow-up were recorded. Surgery was deemed successful if the patient’s visual axis was uncovered, and if there was no significant change in palpebral aperture height.

Statistical analysis was done using student’s t-test and p value ≤ 0.05 was considered significant.

Surgical technique

Surgery was performed under local anaesthesia. The  upper and lower eyelid skin were infiltrated with 2% lignocaine with 1:200,000 epinephrine. A corneal protective shield was placed. A traction suture was passed centrally through the grey line in the upper eyelid. Extra skin was removed and a skin incision was made with separation of orbicularis from underlying septum. The pre-aponeurotic fat pad was retracted and the anterior surface of the tarsus was exposed. An ellipse with a central height of 6 mm including 3 mm of tarsus and conjunctiva and 3 mm of levator aponeurosis was marked and excised. Care was taken to leave at least 4 mm of tarsus along  the entire length of the eyelid. The elliptical defect in the posterior lamella was closed with 6-0 vicryl sutures. Orbicularis muscle was closed with interrupted 6-0 vicryl suture and skin was closed with a running 5-0 silk suture. Postoperative lubricants were prescribed as required.

A 4-0 nylon suture was then placed through the grey line in the lower eyelid to evert it. A horizontal conjunctival incision was made below the tarsus along the entire length of the eyelid.

The conjunctiva andlower eyelid retractors were separated from the overlying orbicularis. The composite graft from the upper eyelid was sutured to the bottom edge of the inferior tarsus and the cut edge of conjunctiva of the lower

eyelid with a running 6-0 vicryl suture, with the tarsal component uppermost and next to the lower eyelid tarsus. The sutures were externalized and tied over bolsters-and the corneal protective shield removed. Suture tarsorrhaphies were placed medially and laterally through upper and lower eyelids.The 5-0 silk suture was then used as a temporary Frost suture and secured to the forehead with adhesive tapes. 

Results 

Tarsal switch procedure was performed on 14 eyelids of 9 patients.

Table 1 provides summary of the patient demographics and diagnosis

Table 1 Demographic details and diagnosis of patients undergoing tarsal switch procedures

Patient	Sex	Age(years)	Diagnosis	Follow up (months)
1	M	40	CPEO	12
2	M	20	Traumatic ptosis(3rdN Palsy)	12
3	M	31	CPEO	11
4	F	20	CPEO	10
5	M	60	CPEO	10
6	F	35	CPEO	8
7	F	65	CPEO	7
8	F	60	CPEO	6
9	F	65	CPEO	6

All patients had reduced levator muscle function and poor Bell’s response. The Patients ranged in age from 20 years to 65 years (mean age 46.35±16.74 years).

Pre-operative and post-operative clinical findings are presented in Table 2 

TABLE 2 Pre and post-operative measurements of patients undergoing Anterior approach tarsal switch procedure

Patient	Eye	Lagophthalmos	LPS function	Preop PAH	Preop MRD1	Preop MRD2	Post-op MRD1 (Change in mm)	Post-op MRD2 (change in mm)	Change in PAH(mm) (P =0.08)
1	OS	Absent	5	5	-2	7	1(3)	4(3)	0
2	OD	Absent	6	4	-3	7	0.5(3.5)	4.5(2.5)	+1
3	OD	Absent	4	7	-1	8	1(2)	6(2)	+1
	OS	Absent	3	4	-3	7	1(4)	4(3)	0
4	OS	Absent	7	9	0	9	2(2)	7(2)	0
5	OD	Absent	5	4	-3	7	1(4)	4(3)	+1
	OS	Absent	6	5	-1	6	1(2)	4.5(1.5)	+0.5
6	OD	Absent	4	2	-3	5	0.5(3.5)	2(3)	+0.5
	OS	Absent	4	4	-3	7	1(4)	4(3)	+1
7	OD	Absent	5	4	-2	6	1(3)	3(3)	0
	OS	Absent	6	6	-1	7	0.5(1.5)	4.5(2.5)	-1
8	OD	Absent	6	6	-2	8	1(3)	5(3)	0
	OS	Absent	6	4	-1	5	1.5(2.5)	2.5(2.5)	0
9	OD	Absent	5	4	-2	6	1(3)	3(3)	0

MRD- marginal reflex distance, PAH –palpebral aperture height

All patients had reduced ocular motility and poor Bell’s response.

The surgery was performed bilaterally (simultaneously) in 5 patients by experienced surgeon

The mean pre-operative and post-operative MRD1 measurements were – 1.9(range -1 to -3mm) and +1

(range 0.5 to2mm) respectively. The MRD1  increased by 1.5 to 4 mm (mean 2.9mm) and the MRD2 decreased by 1.5 to 3mm (mean 2.6mm). Mean palpebral aperture height was (PAH)  change was non-significant (p=0.08).There were no intra-operative complications, no patient required revision surgery for eyelid asymmetry and contour abnormalities.Overall patient satisfaction was good over a mean follow-up period of 9.1 months (Range 6 to 12 months)

DISCUSSION

Conventional technique of ptosis correction like blepharoplasty, conservative levator resection, frontalis suspension tecnique , in patient  with myopathic ptosis elevates only the upper eyelid and leads to marked risk of severe lagophthalmos and exposure keratitis.^4-13

But our approach along with ptosis correction also addresses the issue of patients poor eye protective mechanisms.

The tarsal switch procedure was originally describe by Massry et al to address complication related to anophthalmic socket³. In this study free tarso-conjunctival graft was taken from the upper eyelid via posterior approach and transfer to the lower eyelid, and if additional ptosis correction was needed then the levator aponeurosis was imbricated in the closure to advance it and to elevate the eyelid further.

In our study concept of autogenous tarsal graft applied to ptosis patient with poor corneal protective mechanisms. The composite graft consisted of tarsus, conjunctiva and levator aponeurosis,and thereby achieved upper lid elevation through both tarsal resection as well as shortening of levator aponeurosis and lower eyelid elevation was achieved through the addition of tarsal graft and through disinsertion of lower-eyelid retractors before placement of graft.

This tarsal switch levator resection procedure effectively elevates the upper eyelid in a predetermined manner and raises the lower eyelid by the same amount. This effectively displaces the palpebral fissure superiorly, thereby opening the visual axis in primary gaze.

Massry et al reported two patients with upper eyelid retraction, who subsequently underwent upper lid recession secondary to myopathic lagophthalmos³

De Martelaere et al reported 1 patient with exposure keratopathy requiring bilateral upper lid recession.

None of our patients developed exposure as the vertical palpebral fissure height increased only marginally and none required revision surgery.

More than half of the patients who underwent a posterior surgical approach developed residual nasal ptosis after surgery due to graft decentration. In addition, 75% patients had a thickened appearance of their pretarsal skin³

Our surgical approach was entirely anterior and we encountered no difficulties like segmental ptosis or lid thickening. These results are similar to the results in the study conducted by De Martelaere et al.¹⁴

There are several advantages of our procedure aside from the previously stated low incidence of postoperative exposure keratopathy. First, an autogenous graft is used to recess the lower eyelid. Thus, there is no comorbidity associated with the need to harvest a hard palate mucosal graft or ear cartilage graft or to use allogenic material. Second, there is no significant shrinkage of the graft, and the eyelid position initially achieved remains largely unchanged over time. This allows for a more predictable and stable postoperative course. Third, cosmetic outcomes in our study were excellent, with no reoperations required for eyelid asymmetry or contour abnormalities. Again, this points to the predictable nature of this procedure and correlates with the excellent patient satisfaction. Despite resection of part of the tarsal plate from the upper eyelid and probable loss of some of the accessory lacrimal glands, there was no complaint of dry eye problems in the patients.

The aim of the ptosis surgery in these patients was a modest improvement in MRD1 to improve visual function, and this was achieved in all eyelids. This modest elevation of the upper eyelid together with a modest elevation of the lower eyelid minimizes the risk of corneal exposure problems.

This  technique displaces the palpebral fissure superiorly while largely maintaining the original height of the palpebral fissure, thus further reducing the possibility of lagophthalmos and exposure. The vertical palpebral fissure height increased only marginally which was statistically insignificant (p=0.08).

In conclusion, the tarsal switch procedure effectively elevates upper and lower eyelid unmasking visual axis in primary gaze with no significant change in palpebral aperture height (PAH), decreases risk of postoperative exposure by raising lower eyelid in patients with poor eye protective mechanisms.

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