12.1 Goals

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  To discuss external ptosis repair as a cornerstone of the ophthalmic plastic surgeon’s repertoire for elevating a ptotic eyelid to improve superior visual field defects as well as cosmesis of a droopy upper eyelid.

  
  
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  Using an external skin incision placed within the upper eyelid crease to access the underlying levator superioris tarsi muscle.

  
  
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  Enhance eyelid elevation by reanchoring a plicated or resected levator muscle to the tarsal plate, thereby strengthening its effect.

12.2 Advantages

External ptosis repair is a powerful approach to elevating the eyelid in patients with a healthy levator having normal or near-normal function. The approach involves direct visualization of the levator muscle, allowing for visual confirmation of levator dehiscence when this etiology is suspected or for biopsy if clinically indicated. External ptosis repair can be considered even in cases of an abnormal muscle, if sufficient levator function is measured preoperatively. The procedure can often be performed with only local anesthesia and proper monitoring of the patient. If local anesthesia is used, adjustments can even be made intraoperatively as the patient is awake and can help in the assessment of proper lid height and contour. In addition, an upper eyelid blepharoplasty of variable size may easily be performed in conjunction as it does not require a separate incision. Finally, a major benefit is that recovery is quick, with patients often seeing improvements just days after surgery once most swelling has resolved.

12.3 Expectations

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  Patients should be aware that the anticipated improvement in vision is related to an improved superior visual field; other underlying visual issues will not be improved with this surgery.

  
  
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  While the aim is for both lids to appear symmetric, there is some degree of inherent surgical and healing variability that can lead to asymmetry; the surgeon needs to discuss this with the patient preoperatively.

  
  
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  In cases of reduced levator function or histologically abnormal levator muscle, the degree and predictability of elevation are reduced.

  
  
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  Patients should be counseled to be patient as the eyelids heal and in the postoperative use of ice, and elevation and activity limitation to minimize edema and ecchymosis.

12.4 Key Principles

External ptosis repair allows for direct visualization and anatomic correction of the most common cause of ptosis, namely dehiscence of the levator aponeurosis. It offers a powerful elevation of the upper eyelid in an otherwise normal functioning levator muscle. The external upper eyelid crease incision is the same as that of an upper blepharoplasty and therefore these procedures can easily be coupled without additional surgical time. Patient cooperation during surgery will help achieve both appropriate lid height and contour.

12.5 Indications

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  External ptosis repair is intended to correct blepharoptosis due to defects of the levator palpebrae superioris.

  
  
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  The most common indication is a dehiscence of the levator aponeurosis from its normal position. This is often seen due to involutional changes over time, but can occur in patients with a history of trauma or repetitive traction on the eyelid, due to either rubbing or long-term use of rigid contact lenses. ^{1 ,​ 2}

  
  
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  Other indications:

  
  
  
  
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    Superior visual field impairment (functional). ¹

    
    
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    Poorly fitting prosthesis in setting of anophthalmic socket (functional). ¹

    
    
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    Asymmetry of eyelid contour and height (cosmetic). ¹

12.6 Contraindications

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  External ptosis repair requires some degree of levator excursion/function and therefore is relatively contraindicated in cases of severely reduced levator function. ^{1 ,​ 3}

  
  
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  Less than 5 mm of function should prompt consideration of other surgical approaches.

  
  
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  Relative contraindications include the following:

  
  
  
  
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    Severe congenital ptosis. ²

    
    
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    Ptosis due to third nerve palsies in which the levator muscle lacks innervation. ^{1 ,​ 4}

    
    
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    Myopathies such as central progressive external ophthalmoplegia and oculopharyngeal dystrophy. ⁴

    
    
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    Neuromuscular disease such as myasthenia gravis. ⁴

    
    
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    Severe dry eyes and corneal disease.

  
  
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  Variability of measurements during an examination or across separate examinations should raise suspicion and prompt further investigation before contemplation of surgical repair.

  
  
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  Consideration should be given to whether patients will be able to cooperate during surgery if local anesthesia is being utilized, as they will need to open their eyes to help the surgeon assess for proper lid height and contour.

  
  
  
  
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    While external levator resections are performed under general anesthesia in cases of congenital ptosis, the external approach is best suited to local anesthesia in which patients are able to participate in opening and closing their eyes throughout the surgery.