ANATOMICAL STUDY
Transcaruncular Approach to the Isolated Medial Orbital Wall Fracture: Technical Perspective and Cadaveric Dissection David E. Morris, MD, Benjamin Liliav, MD, and Mimis N. Cohen, MD Abstract: With technologic progress in imaging for patients with trauma, isolated medial orbital wall fractures have become an increasingly appreciated injury. Given that these injuries may cause deformity and functional deficit, reconstruction is warranted in some cases. Surgical approaches to the medial orbit have evolved, and there are particular benefits of the transcaruncular approach. This approach was used to reconstruct isolated medial orbital wall fractures for 9 patients over a 33-month period. A cadaver dissection demonstrating the approach combined with skull images is presented to illustrate anatomic details and technical points of the dissection. Key Words: Medial orbital wall fracture, transcaruncular, orbital anatomy (J Craniofac Surg 2014;25: 1047–1049)
W
ith the evolution of imaging technology for patients with trauma, the isolated medial orbital wall fracture has become an increasingly recognized entity in recent years. Such fractures cannot be delineated well on plain radiographs but are obvious on computed tomographic (CT) scan, the latter of which has become routine imaging for patients with facial trauma. Surgical techniques have led to progress in the treatment of the isolated medial orbital wall fracture. Recent reports have pointed out the advantages of the transcaruncular approach for treating isolated medial orbital wall fractures.1–3 Before this, the medial orbital wall was typically approached through coronal, the upper eyelid, or lower eyelid approaches. There are disadvantages with these approaches including length of scar, extent of dissection required, indirect route of dissection, and limited exposure. Like others, our group has found the transcaruncular approach to be useful, and it has become our preferred approach for isolated medial orbital wall fractures. The purpose of this article was to demonstrate via cadaveric dissection the transcaruncular approach to isolated medial wall fractures, focusing on anatomic details and related technical points of the exposure.
From the Division of Plastic, Reconstructive, and Cosmetic Surgery, The University of Illinois at Chicago; and Division of Plastic Surgery, Mount Sinai Hospital, Chicago, Illinois. Received December 3, 2013. Accepted for publication January 14, 2014. Address correspondence and reprint requests to David E. Morris, MD, The Craniofacial Center, University of Illinois at Chicago, 811 S Paulina Ave, Chicago, IL 60612; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000761
MATERIALS AND METHODS Clinical From July 2010 to April 2013, a total of 9 patients underwent reconstruction of the medial orbital wall for an isolated medial orbital wall fracture using the transcaruncular approach. The patients were evaluated clinically and radiographically with thin-slice CT scan, and all had formal preoperative ophthalmologic consultation. Indications for repair were based on findings including the size of defect, enophthalmos, diplopia, and restriction of eye movement. No patient had acute entrapment on presentation. The technique used for transcaruncular exposure is detailed below in the anatomic study section. After exposure of the fracture, a resorbable orbital implant was placed overlying the stable, nondisplaced edges of the fracture, reconstituting the medial orbital wall. Postoperative CT scan was obtained on each patient immediately after the reconstruction.
Anatomic Studies Photographs of the pertinent anatomy of a skull model were taken. A cadaveric dissection of the medial orbital wall was performed following the sequence used in the treatment of an isolated medial orbital wall fracture. Photographs of the skull and those from the cadaveric dissection are included in this article with a sequential description of the exposure.
RESULTS Clinical There were no immediate or long-term complications for the group of patients treated. Postoperative CT scans demonstrated appropriate positioning of the resorbable implant, buttressed across the defect, for all cases. There were no cases of reoperation.
Anatomic Studies Images of the skull demonstrate skeletal anatomy that is pertinent to the transcaruncular approach. The medial aspect of the orbit consists of the medial orbital rim and the medial orbital wall. The medial orbital rim is composed of the maxillary process of the frontal bone (Fig. 1A) and the frontal process of the maxilla (Fig. 1B). The medial orbital wall is composed of the lacrimal bone and the ethmoid bone. The irregularly shaped lacrimal bone (Fig. 2A) lies immediately posterior to the frontal process of the maxilla. Together, these 2 bones frame the lacrimal fossa (Fig. 2B), which contains the lacrimal sac. The ethmoid bone (Fig. 3A) lies immediately posterior to the lacrimal bone and separates the medial orbit from the upper part of the nasal cavity. It is extensively pneumatized by the ethmoid air cells (Fig. 3B), making the medial wall of the orbit fragile, hence the term lamina papyracea (paper thin).
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1047
Morris et al
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
FIGURE 1. The maxillary process of the frontal bone (A) and the frontal process of the maxilla (B) comprise the medial orbital rim.
FIGURE 5. The caruncle is identified, here lying just anterior to the elevator.
FIGURE 2. The lacrimal bone (A) and the ethmoid bone comprise the medial orbital wall. The lacrimal gland (B) underlies the lacrimal bone and the frontal process of maxilla. FIGURE 6. Schematic demonstrating plan of the transcaruncular approach. The posterior lacrimal crest is identified by palpation and dissection carried posterior to this.
FIGURE 3. The ethmoid bone (A) is extensively pneumatized by air cells (B). FIGURE 7. After incision just posterior to the caruncle, the posterior lacrimal crest is identified by palpation with an elevator and dissection proceeds in a direction posterior to the crest with tenotomy scissors.
FIGURE 4. Anterior and posterior ethmoidal foramina lie along the frontoethmoid suture.
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FIGURE 8. Dissection is carried through the periosteum to expose the bony medial orbital wall.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
Isolated Medial Orbital Wall Fractures
carried out toward the fracture (Fig. 8). The stable, nondisplaced superior, inferior, anterior, and posterior edges are identified. Here, the exposure is complete and attention is turned toward choosing and, if needed, contouring an implant to lay over these stable buttresses. In exposing the fracture, the anterior and/or posterior ethmoidal arteries may be encountered depending on the individual case; if so, they are cauterized with bipolar cautery. Both are demonstrated in this cadaver dissection (Fig. 9). After reconstruction of the orbital wall, closure is performed with 3 interrupted fast-absorbing chromic sutures placing knot on the inside. FIGURE 9. The anterior (A) and posterior (B) ethmoidal arteries are identified exiting from their respective foramina along the frontoethmoid suture.
The frontoethmoidal suture separates the medial wall from the orbital roof. The anterior and posterior ethmoidal foramina (Fig. 4) are located along this suture line and designate the canals through which the anterior and posterior ethmoidal arteries emerge.
Surgical Approach After placement of a corneal shield, the caruncle and the semilunar fold are identified (Fig. 5). The caruncle is a small fleshy keratinized mound of sebaceous tissue that functions in lubricating, cleansing, as well as moisturizing the eye and has an antibacterial function. The semilunar fold is an invagination of the medial conjunctiva. A small amount of lidocaine containing epinephrine is infiltrated into the planned area of dissection, just deep to the conjunctiva along the planned incision line. A 10-mm–long vertical incision is made with a no. 15 blade just posterior to the caruncle. The plane of the subsequent dissection is established with a Freer elevator; this is placed within the incision, and the posterior lacrimal crest is palpated with the tip of the elevator. The posterior lacrimal crest marks the attachment of the posterior limb of the medial canthal tendon; thus, the lacrimal sac is situated anterior to this bony landmark (Fig. 6). Having established the direction for subsequent dissection, tenotomy scissors are used to dissect in a direction just posterior to the posterior lacrimal crest (Fig. 7). By aiming posterior to the posterior lacrimal crest, the surgeon avoids injury to the lacrimal sac and to the medial canthus. This dissection plane should be direct and relatively avascular. Once the periosteum of the medial orbital wall is reached, the periosteum is incised and a clean subperiosteal dissection is
DISCUSSION Multiple surgical approaches to the isolated medial orbital wall fracture have been previously described, including coronal, transconjunctival, subciliary, lower lid, medial canthal, medial brow, and endoscopic approaches. Recently, multiple groups have advocated the transcaruncular approach for its advantages of enabling safe, direct exposure and visualization of the medial wall while subverting a cutaneous scar and preserving the medial canthus and lacrimal apparatus. Our clinical experience confirms the value of this approach for isolated medial orbital wall fractures, and as such, it has been our preferred approach since July of 2010. As others have reported, we also have found that, for combined orbital floor/medial orbital wall fractures in which the medial orbital wall component extends high up on the medial wall, the extension of a subconjunctival approach for the floor into a transcaruncular approach for the medial wall has been useful. When our group initially started using the transcaruncular approach in the context of orbital trauma, the literature was limited in terms of technical description of the approach. Given the complex regional anatomy, we felt that cadaver dissection would be useful and that the resultant images presented here will add 1 other facet to the education of those contemplating using this approach.
REFERENCES 1. Choi M, Flores RL. Medial orbital wall fractures and the transcaruncular approach. J Craniofac Surg 2012;23:696–701 2. Lee K, Snape L. Efficacy of transcaruncular approach to reconstruct isolated medial orbital fracture. J Maxillofac Oral Surg 2010;9:142–145 3. Han K, Choi JH, Choi TH, et al. Comparison of endoscopic endonasal reduction and transcaruncular reduction for the treatment of medial orbital wall fractures. Ann Plast Surg 2009;62:258–264
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1049
Transcaruncular Approach to the Isolated Medial Orbital Wall Fracture: Technical Perspective and Cadaveric Dissection David E. Morris, MD, Benjamin Liliav, MD, and Mimis N. Cohen, MD Abstract: With technologic progress in imaging for patients with trauma, isolated medial orbital wall fractures have become an increasingly appreciated injury. Given that these injuries may cause deformity and functional deficit, reconstruction is warranted in some cases. Surgical approaches to the medial orbit have evolved, and there are particular benefits of the transcaruncular approach. This approach was used to reconstruct isolated medial orbital wall fractures for 9 patients over a 33-month period. A cadaver dissection demonstrating the approach combined with skull images is presented to illustrate anatomic details and technical points of the dissection. Key Words: Medial orbital wall fracture, transcaruncular, orbital anatomy (J Craniofac Surg 2014;25: 1047–1049)
W
ith the evolution of imaging technology for patients with trauma, the isolated medial orbital wall fracture has become an increasingly recognized entity in recent years. Such fractures cannot be delineated well on plain radiographs but are obvious on computed tomographic (CT) scan, the latter of which has become routine imaging for patients with facial trauma. Surgical techniques have led to progress in the treatment of the isolated medial orbital wall fracture. Recent reports have pointed out the advantages of the transcaruncular approach for treating isolated medial orbital wall fractures.1–3 Before this, the medial orbital wall was typically approached through coronal, the upper eyelid, or lower eyelid approaches. There are disadvantages with these approaches including length of scar, extent of dissection required, indirect route of dissection, and limited exposure. Like others, our group has found the transcaruncular approach to be useful, and it has become our preferred approach for isolated medial orbital wall fractures. The purpose of this article was to demonstrate via cadaveric dissection the transcaruncular approach to isolated medial wall fractures, focusing on anatomic details and related technical points of the exposure.
From the Division of Plastic, Reconstructive, and Cosmetic Surgery, The University of Illinois at Chicago; and Division of Plastic Surgery, Mount Sinai Hospital, Chicago, Illinois. Received December 3, 2013. Accepted for publication January 14, 2014. Address correspondence and reprint requests to David E. Morris, MD, The Craniofacial Center, University of Illinois at Chicago, 811 S Paulina Ave, Chicago, IL 60612; E-mail: [email protected] The authors report no conflicts of interest. Copyright © 2014 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000000761
MATERIALS AND METHODS Clinical From July 2010 to April 2013, a total of 9 patients underwent reconstruction of the medial orbital wall for an isolated medial orbital wall fracture using the transcaruncular approach. The patients were evaluated clinically and radiographically with thin-slice CT scan, and all had formal preoperative ophthalmologic consultation. Indications for repair were based on findings including the size of defect, enophthalmos, diplopia, and restriction of eye movement. No patient had acute entrapment on presentation. The technique used for transcaruncular exposure is detailed below in the anatomic study section. After exposure of the fracture, a resorbable orbital implant was placed overlying the stable, nondisplaced edges of the fracture, reconstituting the medial orbital wall. Postoperative CT scan was obtained on each patient immediately after the reconstruction.
Anatomic Studies Photographs of the pertinent anatomy of a skull model were taken. A cadaveric dissection of the medial orbital wall was performed following the sequence used in the treatment of an isolated medial orbital wall fracture. Photographs of the skull and those from the cadaveric dissection are included in this article with a sequential description of the exposure.
RESULTS Clinical There were no immediate or long-term complications for the group of patients treated. Postoperative CT scans demonstrated appropriate positioning of the resorbable implant, buttressed across the defect, for all cases. There were no cases of reoperation.
Anatomic Studies Images of the skull demonstrate skeletal anatomy that is pertinent to the transcaruncular approach. The medial aspect of the orbit consists of the medial orbital rim and the medial orbital wall. The medial orbital rim is composed of the maxillary process of the frontal bone (Fig. 1A) and the frontal process of the maxilla (Fig. 1B). The medial orbital wall is composed of the lacrimal bone and the ethmoid bone. The irregularly shaped lacrimal bone (Fig. 2A) lies immediately posterior to the frontal process of the maxilla. Together, these 2 bones frame the lacrimal fossa (Fig. 2B), which contains the lacrimal sac. The ethmoid bone (Fig. 3A) lies immediately posterior to the lacrimal bone and separates the medial orbit from the upper part of the nasal cavity. It is extensively pneumatized by the ethmoid air cells (Fig. 3B), making the medial wall of the orbit fragile, hence the term lamina papyracea (paper thin).
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1047
Morris et al
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
FIGURE 1. The maxillary process of the frontal bone (A) and the frontal process of the maxilla (B) comprise the medial orbital rim.
FIGURE 5. The caruncle is identified, here lying just anterior to the elevator.
FIGURE 2. The lacrimal bone (A) and the ethmoid bone comprise the medial orbital wall. The lacrimal gland (B) underlies the lacrimal bone and the frontal process of maxilla. FIGURE 6. Schematic demonstrating plan of the transcaruncular approach. The posterior lacrimal crest is identified by palpation and dissection carried posterior to this.
FIGURE 3. The ethmoid bone (A) is extensively pneumatized by air cells (B). FIGURE 7. After incision just posterior to the caruncle, the posterior lacrimal crest is identified by palpation with an elevator and dissection proceeds in a direction posterior to the crest with tenotomy scissors.
FIGURE 4. Anterior and posterior ethmoidal foramina lie along the frontoethmoid suture.
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FIGURE 8. Dissection is carried through the periosteum to expose the bony medial orbital wall.
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery • Volume 25, Number 3, May 2014
Isolated Medial Orbital Wall Fractures
carried out toward the fracture (Fig. 8). The stable, nondisplaced superior, inferior, anterior, and posterior edges are identified. Here, the exposure is complete and attention is turned toward choosing and, if needed, contouring an implant to lay over these stable buttresses. In exposing the fracture, the anterior and/or posterior ethmoidal arteries may be encountered depending on the individual case; if so, they are cauterized with bipolar cautery. Both are demonstrated in this cadaver dissection (Fig. 9). After reconstruction of the orbital wall, closure is performed with 3 interrupted fast-absorbing chromic sutures placing knot on the inside. FIGURE 9. The anterior (A) and posterior (B) ethmoidal arteries are identified exiting from their respective foramina along the frontoethmoid suture.
The frontoethmoidal suture separates the medial wall from the orbital roof. The anterior and posterior ethmoidal foramina (Fig. 4) are located along this suture line and designate the canals through which the anterior and posterior ethmoidal arteries emerge.
Surgical Approach After placement of a corneal shield, the caruncle and the semilunar fold are identified (Fig. 5). The caruncle is a small fleshy keratinized mound of sebaceous tissue that functions in lubricating, cleansing, as well as moisturizing the eye and has an antibacterial function. The semilunar fold is an invagination of the medial conjunctiva. A small amount of lidocaine containing epinephrine is infiltrated into the planned area of dissection, just deep to the conjunctiva along the planned incision line. A 10-mm–long vertical incision is made with a no. 15 blade just posterior to the caruncle. The plane of the subsequent dissection is established with a Freer elevator; this is placed within the incision, and the posterior lacrimal crest is palpated with the tip of the elevator. The posterior lacrimal crest marks the attachment of the posterior limb of the medial canthal tendon; thus, the lacrimal sac is situated anterior to this bony landmark (Fig. 6). Having established the direction for subsequent dissection, tenotomy scissors are used to dissect in a direction just posterior to the posterior lacrimal crest (Fig. 7). By aiming posterior to the posterior lacrimal crest, the surgeon avoids injury to the lacrimal sac and to the medial canthus. This dissection plane should be direct and relatively avascular. Once the periosteum of the medial orbital wall is reached, the periosteum is incised and a clean subperiosteal dissection is
DISCUSSION Multiple surgical approaches to the isolated medial orbital wall fracture have been previously described, including coronal, transconjunctival, subciliary, lower lid, medial canthal, medial brow, and endoscopic approaches. Recently, multiple groups have advocated the transcaruncular approach for its advantages of enabling safe, direct exposure and visualization of the medial wall while subverting a cutaneous scar and preserving the medial canthus and lacrimal apparatus. Our clinical experience confirms the value of this approach for isolated medial orbital wall fractures, and as such, it has been our preferred approach since July of 2010. As others have reported, we also have found that, for combined orbital floor/medial orbital wall fractures in which the medial orbital wall component extends high up on the medial wall, the extension of a subconjunctival approach for the floor into a transcaruncular approach for the medial wall has been useful. When our group initially started using the transcaruncular approach in the context of orbital trauma, the literature was limited in terms of technical description of the approach. Given the complex regional anatomy, we felt that cadaver dissection would be useful and that the resultant images presented here will add 1 other facet to the education of those contemplating using this approach.
REFERENCES 1. Choi M, Flores RL. Medial orbital wall fractures and the transcaruncular approach. J Craniofac Surg 2012;23:696–701 2. Lee K, Snape L. Efficacy of transcaruncular approach to reconstruct isolated medial orbital fracture. J Maxillofac Oral Surg 2010;9:142–145 3. Han K, Choi JH, Choi TH, et al. Comparison of endoscopic endonasal reduction and transcaruncular reduction for the treatment of medial orbital wall fractures. Ann Plast Surg 2009;62:258–264
© 2014 Mutaz B. Habal, MD
Copyright © 2014 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
1049
