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Technique for removing donor sclera by eyeball extrusion
a r c h s o c e s p o f t a l m o l . 2 0 1 2;8 7(9):294–296
ARCHIVOS DE LA SOCIEDAD ESPAÑOLA DE OFTALMOLOGÍA www.elsevier.es/oftalmologia
Short communication
Technique for removing donor sclera by eyeball extrusion夽 F. González del Valle, M. Álvarez Portela ∗ , J. Lara Medina, J. Celis Sánchez, A. Barrajón Rodríguez Servicio de Oftalmología, Hospital General La Mancha Centro, Alcázar de San Juan, Ciudad Real, Spain
a r t i c l e
i n f o
a b s t r a c t
Article history:
Purpose: To describe a surgery technique for removing donor sclera tissue after corneo-
Received 28 January 2011
scleral button excision.
Accepted 19 July 2011
Results: The extrusion technique is easy to perform. It allows the complete scleral extraction
Available online 22 October 2012
its total clean up to be performed, as well as making easier to isolate the retina and uveal
Keywords:
study of ocular structures.
tissue. This technique could have an important role in the anatomical and morphological Sclera
© 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L. All rights
Donor
reserved.
Extrusion Eye bank Transplantation Uvea Retina
Técnica de extracción de esclera donante mediante extrusión del globo ocular r e s u m e n Palabras clave:
Objetivo: Describir una técnica quirúrgica de extracción escleral en ojo de donante tras la
Esclera
escisión del botón corneoescleral.
Donante
Conclusiones: La técnica de extrusión es una técnica fácil de realizar, que permite la
Extrusión
extracción escleral completa facilitando además su limpieza total y el aislamiento de
Banco de ojos
la retina y del tejido uveal. Esta técnica podría tener un papel importante en el
Úvea
estudio anatómico y morfológico de las estructuras oculares.
Trasplante Retina
© 2011 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L. Todos los derechos reservados.
夽
Please cite this article: González del Valle F, et al. Técnica de extracción de esclera donante mediante extrusión del globo ocular. Arch Soc Esp Oftalmol. 2012;87:294–6. ∗ Corresponding author. E-mail address: [email protected] (M. Álvarez Portela). 2173-5794/$ – see front matter © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L. All rights reserved.
a r c h s o c e s p o f t a l m o l . 2 0 1 2;8 7(9):294–296
295
Introduction Since organ donation is authorized and regulated in our country, currently with the development of eye banks, ocular tissue has been put to multiple uses and several techniques have been developed for its extraction. As one of the said techniques, extrusion (from the Latin extrudere, to give form to a mass causing it to exit through an opening) is described below as a technique for obtaining sclera.
Surgical technique The technique begins after obtaining the corneal-scleral button in sterile conditions following the technical guidelines for ocular tissue of the European Eye Bank Association (EEBA, www.europeaneyebanks.org).1 Using a spatula, we traverse 360◦ of the corneoscleral incision to release the uveoscleral junctions (Fig. 1). Subsequently, with the curved dissection scissors we first cut the sclera from the edge of the cornea up to the equator of the ocular globe, releasing at the same time the junctions with the uvea. Thereafter, a second cut is made at 180◦ of the first one with the same procedure (Fig. 2). Then we proceed to extrude the content of the ocular globe
Fig. 3 – Uveal extrusion maneuver.
Fig. 1 – 360◦ dissection of the sclero-corneal limbus with spatula.
(pressing the entire circumference of the donor sclera) and it will come out in a single piece (choroidal globe), cutting the nerve ancillary vessel connections to the sclera (Fig. 3), as well as the optic nerve with a cutting instrument. When carrying out this technique, we will be able to observe important references in the anatomy of the eye: uveoscleral junctions which, at the anterior level are more relaxed than in the equator and the posterior pole. This explains why choroidal detachments are more frequent at this level. The ciliary body, the pars plana and pars plicata, ora serrata; the long ciliary nerves; the lamina fusca, which is the innermost layer of the sclera and is made up by lax conjunctive tissue and melanocytes. Its inward side has channels for nerves and ciliary vessels. At the equatorial level, the vorticose veins tangentially traverse the sclera in the posterior direction and exit through orifices that are located at 14–18 mm behind the limbus. The exit points of the sclera for these veins are more posterior in the temporal quadrants than in the nasal ones and drain the blood from the choroids towards the ophthalmic vein in the orbit. In the posterior segment we find the short nerves and ciliary vessels as well as the optic nerve.
Discussion
Fig. 2 – Scleral cuts.
Anatomy is an essential subject in medicine and is particularly relevant in surgery specialties.2 In ophthalmology, this
296
a r c h s o c e s p o f t a l m o l . 2 0 1 2;8 7(9):294–296
Fig. 4 – Identification of the long ciliary nerve and the lamina fusca.
Fig. 6 – Isolation of ocular structures for histological study.
Fig. 5 – Final appearance of the sclera after the procedure.
knowledge is acquired mainly from written sources because studying eyes in vivo is very difficult. Many articles have demonstrated the benefits of an adequate knowledge of anatomy for post-graduate training of physicians for surgical specialties.3 With the technique described above, donations are utilized to supplement anatomy training of ophthalmology resident physicians. It is also useful to train in the use of ocular tissue and microsurgery instruments. The extraction in the donor enables the identification of adjacent structures, including the insertion of the extraocular muscles, small vessels, the optic nerve insertion and Tenon’s fascia. The intrinsic study of the globe reveals the sclera, the lamina fusca, the suprachoroids, the ciliary nerves and vessels (Fig. 4). With the extrusion maneuver, we separate the uvea from the sclera, revealing the pathways and interconnections of vessels and nerves between both structures. Very rarely an ophthalmologist is able to study uveal anatomy and identify its structures: iris, the ciliary body with the pars plicata and pars plana, as well as the choroids. The study can be completed isolating the lens and the retina from the uveal tissue with an adequate technique. The
extrusion technique is easy to perform and it enables a complete extraction of the sclera as well as facilitating its cleaning for subsequent use (Fig. 5). It could be important for studying the choroids, the retina, the vitreous body and the posterior chamber of the eye as it allows the anatomic preservation of all these structures (Fig. 6).
Conflict of interest The authors declare no conflict of interest.
references
1. Technical guidelines for ocular tissue. European Eye Bank Association [cited 12 May 2009]. Available from: http://www.europeaneyebanks.org 2. Drake RL, Lowrie DJ, Prewitt CM. Survey of gross anatomy, microscopic anatomy, neuroscience, and embryology courses in medical school curricula in the United States. Anat Rec. 2002;269:118–22. 3. Kivell TL, Doyle SK, Madden RH, Mitchell TL, Sims EL. An interactive method for teaching anatomy of the human eye for medical students in ophthalmology clinical rotations. Anat Sci Educ. 2009;2:173–8.
ARCHIVOS DE LA SOCIEDAD ESPAÑOLA DE OFTALMOLOGÍA www.elsevier.es/oftalmologia
Short communication
Technique for removing donor sclera by eyeball extrusion夽 F. González del Valle, M. Álvarez Portela ∗ , J. Lara Medina, J. Celis Sánchez, A. Barrajón Rodríguez Servicio de Oftalmología, Hospital General La Mancha Centro, Alcázar de San Juan, Ciudad Real, Spain
a r t i c l e
i n f o
a b s t r a c t
Article history:
Purpose: To describe a surgery technique for removing donor sclera tissue after corneo-
Received 28 January 2011
scleral button excision.
Accepted 19 July 2011
Results: The extrusion technique is easy to perform. It allows the complete scleral extraction
Available online 22 October 2012
its total clean up to be performed, as well as making easier to isolate the retina and uveal
Keywords:
study of ocular structures.
tissue. This technique could have an important role in the anatomical and morphological Sclera
© 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L. All rights
Donor
reserved.
Extrusion Eye bank Transplantation Uvea Retina
Técnica de extracción de esclera donante mediante extrusión del globo ocular r e s u m e n Palabras clave:
Objetivo: Describir una técnica quirúrgica de extracción escleral en ojo de donante tras la
Esclera
escisión del botón corneoescleral.
Donante
Conclusiones: La técnica de extrusión es una técnica fácil de realizar, que permite la
Extrusión
extracción escleral completa facilitando además su limpieza total y el aislamiento de
Banco de ojos
la retina y del tejido uveal. Esta técnica podría tener un papel importante en el
Úvea
estudio anatómico y morfológico de las estructuras oculares.
Trasplante Retina
© 2011 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L. Todos los derechos reservados.
夽
Please cite this article: González del Valle F, et al. Técnica de extracción de esclera donante mediante extrusión del globo ocular. Arch Soc Esp Oftalmol. 2012;87:294–6. ∗ Corresponding author. E-mail address: [email protected] (M. Álvarez Portela). 2173-5794/$ – see front matter © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L. All rights reserved.
a r c h s o c e s p o f t a l m o l . 2 0 1 2;8 7(9):294–296
295
Introduction Since organ donation is authorized and regulated in our country, currently with the development of eye banks, ocular tissue has been put to multiple uses and several techniques have been developed for its extraction. As one of the said techniques, extrusion (from the Latin extrudere, to give form to a mass causing it to exit through an opening) is described below as a technique for obtaining sclera.
Surgical technique The technique begins after obtaining the corneal-scleral button in sterile conditions following the technical guidelines for ocular tissue of the European Eye Bank Association (EEBA, www.europeaneyebanks.org).1 Using a spatula, we traverse 360◦ of the corneoscleral incision to release the uveoscleral junctions (Fig. 1). Subsequently, with the curved dissection scissors we first cut the sclera from the edge of the cornea up to the equator of the ocular globe, releasing at the same time the junctions with the uvea. Thereafter, a second cut is made at 180◦ of the first one with the same procedure (Fig. 2). Then we proceed to extrude the content of the ocular globe
Fig. 3 – Uveal extrusion maneuver.
Fig. 1 – 360◦ dissection of the sclero-corneal limbus with spatula.
(pressing the entire circumference of the donor sclera) and it will come out in a single piece (choroidal globe), cutting the nerve ancillary vessel connections to the sclera (Fig. 3), as well as the optic nerve with a cutting instrument. When carrying out this technique, we will be able to observe important references in the anatomy of the eye: uveoscleral junctions which, at the anterior level are more relaxed than in the equator and the posterior pole. This explains why choroidal detachments are more frequent at this level. The ciliary body, the pars plana and pars plicata, ora serrata; the long ciliary nerves; the lamina fusca, which is the innermost layer of the sclera and is made up by lax conjunctive tissue and melanocytes. Its inward side has channels for nerves and ciliary vessels. At the equatorial level, the vorticose veins tangentially traverse the sclera in the posterior direction and exit through orifices that are located at 14–18 mm behind the limbus. The exit points of the sclera for these veins are more posterior in the temporal quadrants than in the nasal ones and drain the blood from the choroids towards the ophthalmic vein in the orbit. In the posterior segment we find the short nerves and ciliary vessels as well as the optic nerve.
Discussion
Fig. 2 – Scleral cuts.
Anatomy is an essential subject in medicine and is particularly relevant in surgery specialties.2 In ophthalmology, this
296
a r c h s o c e s p o f t a l m o l . 2 0 1 2;8 7(9):294–296
Fig. 4 – Identification of the long ciliary nerve and the lamina fusca.
Fig. 6 – Isolation of ocular structures for histological study.
Fig. 5 – Final appearance of the sclera after the procedure.
knowledge is acquired mainly from written sources because studying eyes in vivo is very difficult. Many articles have demonstrated the benefits of an adequate knowledge of anatomy for post-graduate training of physicians for surgical specialties.3 With the technique described above, donations are utilized to supplement anatomy training of ophthalmology resident physicians. It is also useful to train in the use of ocular tissue and microsurgery instruments. The extraction in the donor enables the identification of adjacent structures, including the insertion of the extraocular muscles, small vessels, the optic nerve insertion and Tenon’s fascia. The intrinsic study of the globe reveals the sclera, the lamina fusca, the suprachoroids, the ciliary nerves and vessels (Fig. 4). With the extrusion maneuver, we separate the uvea from the sclera, revealing the pathways and interconnections of vessels and nerves between both structures. Very rarely an ophthalmologist is able to study uveal anatomy and identify its structures: iris, the ciliary body with the pars plicata and pars plana, as well as the choroids. The study can be completed isolating the lens and the retina from the uveal tissue with an adequate technique. The
extrusion technique is easy to perform and it enables a complete extraction of the sclera as well as facilitating its cleaning for subsequent use (Fig. 5). It could be important for studying the choroids, the retina, the vitreous body and the posterior chamber of the eye as it allows the anatomic preservation of all these structures (Fig. 6).
Conflict of interest The authors declare no conflict of interest.
references
1. Technical guidelines for ocular tissue. European Eye Bank Association [cited 12 May 2009]. Available from: http://www.europeaneyebanks.org 2. Drake RL, Lowrie DJ, Prewitt CM. Survey of gross anatomy, microscopic anatomy, neuroscience, and embryology courses in medical school curricula in the United States. Anat Rec. 2002;269:118–22. 3. Kivell TL, Doyle SK, Madden RH, Mitchell TL, Sims EL. An interactive method for teaching anatomy of the human eye for medical students in ophthalmology clinical rotations. Anat Sci Educ. 2009;2:173–8.