AlphaCorTM: A Novel Approach to Minimize Late Post-operative Complications

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AlphaCorTM A Novel Approach to Minimize Late
Post-operative Complications

• V. Ngakeng MD, M. Price PhD. MBA, F. Price MD.

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The AlphaCor artificial cornea (Addition
Technology, Des Plaines, IL)

• The Chirila Kpro
• Used for high risk grafts
• Hydrophilic polymer, poly (2-hydroxyethyl
  methacrylate) (PHEMA)

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AlphaCor Implantation

• First implanted in a patient in October 1998 in
  Australia
• Surgical technique is a two-stage procedure
• Stage 1
• corneal lamellar dissection
• 3 to 3.5 mm central disc of corneal tissue is
  removed from the posterior stromal bed
• device is implanted into the lamellar pocket.
• Stage 2
• removal of a central 3 mm diameter disc of
  corneal tissue from the anterior flap
• The best possible visual acuity is usually only
  achieved after completion of stage 2

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AlphaCor Implantation Stage 1
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AlphaCor Stage 2
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After Stage 2

• Restrictions
• Avoid smoking
• Topical medications restrictions

• Complications
• Deposits and spoliation
• stromal melting
• Poor biointegration
• Device extrusion
• Hicks et al
• melts occurred in 26
• resulted in device explantation in 65

• Optic deposition
• Betagan - dark brown
• Tobacco smoke hazy brown

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• Purpose
• To describe clinical outcomes of patients who
  underwent implantation of the AlphaCor
  keratoprosthesis without the second stage of the
  procedure
• Methods
• 6 consecutive AlphaCor implantations without
  second stage performed at a single tertiary
  referral center between February 2005 and
  December 2006

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Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics Table 1 Patient Demographics and Treated Eye Characteristics
Case Gender Age Surgery Date Graft Failures Pre Op Ocular History Pre Op VA BCVA Post Op Complications in Postoperative Course
1 F 32 2/2005 2 Aphakia Nystagmus PPV/Lensectomy RD Retinopathy of Prematurity Trabeculectomy HM 6in HM 1ft Elevated IOP RD RPM
2 F 49 5/2005 5 Multiple glaucoma surgeries Keratitis (possibly herpetic) PC IOL Sclerocornea HM1ft HM4ft Band Keratopathy Calcium Deposits Elevated IOP Microcystic Edema
3 M 33 10/2006 3 Baerveldt Tube Globe Rupture Repair Iris Implant PC IOL Trabeculectomy Vitrectomy LP CF10" Elevated IOP
4 M 53 12/2006 2 Aniridia Aphakia Glaucoma RD 20/400 20/300 Elevated IOP Epithelial Defect Hyphema s/p Tube SPK
5 F 39 12/2006 4 ECCE IOL Glaucoma Nystagmus Peters Anomaly LP HM3ft RPM
6 M 73 12/2006 2 Aniridia (traumatic) Globe rupture repair IOL Explantation Phaco IOL PPV CF at 1 feet CF at 4 feet Elevated IOP
CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment CF, Counting Fingers HM, Hand Movements LP, Light Perception IOP, Intraocular Pressure IOL, Intraocular Lens SPK, Superficial Punctate Keratopathy RPM, Retroprosthetic Membrane ECCE IOL, extracapsular cataract extraction with introcular lens BCVA, Best Corrected Visual Acuity RD, Retinal Detachment
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Complications

• No intra-operative complications
• 5 patients developed elevated IOP
• 2 developed retroprosthetic membranes
• None developed
• stromal melting
• aqueous leakage
• Infection
• extrusion
• All in situ and stable with follow-up of 9 to 32
  months

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Conclusions

• By not exposing the keratoprosthesis to the
  outside of the eye, it may be possible to
  minimize, and potentially nearly eliminate, the
  most significant risks of keratoprosthesis
  surgery, which are melting of the tissue
  surrounding the implant, with secondary extrusion
  of the implant or endophthalmitis
• In our small series without the second stage of
  the procedure, no stromal melts have occurred,
  and all devices remain in situ with a mean follow
  up of 17 months
• By maintaining the same corneal surface, degree
  of visual recovery is limited, so this is not
  advisable for patients that need or desire to
  regain better visual recovery than potentially in
  the range of 20/200

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