- Email: [email protected]
Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal
Accepted Manuscript Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal Amanda Watkins, VMD, Gustavo Abuja, DVM DACVS, Laura Javsicas, VMD DACVIM, James Nutt, IV, VMD DACVS PII:
S0737-0806(17)30400-8
DOI:
10.1016/j.jevs.2017.07.006
Reference:
YJEVS 2351
To appear in:
Journal of Equine Veterinary Science
Received Date: 20 April 2017 Revised Date:
21 July 2017
Accepted Date: 23 July 2017
Please cite this article as: Watkins A, Abuja G, Javsicas L, Nutt J IV, Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal, Journal of Equine Veterinary Science (2017), doi: 10.1016/ j.jevs.2017.07.006. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal
SC
TE D
Laura Javsicas VMD DACVIMa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
M AN U
Gustavo Abuja DVM DACVSa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
RI PT
Amanda Watkins VMDa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
AC C
EP
James Nutt IV VMD DACVSa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
Please direct correspondence to: James Nutt Rhinebeck Equine L.L.P. 26 Losee Lane Rhinebeck, NY 12572
ACCEPTED MANUSCRIPT
RI PT
Abstract This report describes the clinical findings and surgical treatment of a foal with cheiloschisis or cleft lip. Physical exam revealed a diastema between the two first incisors and a robust frenulum in addition to the wide, bi-partite upper lip. Radiographic exam revealed a 2-3 mm area of increased lucency widening the symphysis of the incisive bone, but no other defects of the hard palate. Resting endoscopic exam of the upper respiratory tract was unremarkable. The sagittal area of clefting was removed and the two cut margins were brought together to form a normal lip. The foal recovered well and went on to race training as a two year-old.
SC
Keywords: cleft, lip, surgery, repair, horse, equine
M AN U
1. Case History A 4-month old, 140kg, Thoroughbred filly was presented to the clinic for the evaluation and surgical correction of a congenital cleft upper lip or cheiloschisis. The filly was able to nurse, prehend food with some difficulty, and was a 5/9 body condition score on arrival. The lip was grossly abnormal from birth. Surgical correction was desired to prepare the horse for possible sale and race training.
EP
TE D
2. Clinical Findings On presentation the dorsal lip was wide and flat with a cleft area on midline. An abnormally robust frenulum was present on midline connecting the gingiva to the buccal mucosa. A diastema between the left and right first incisors (Triadan 101 and 201) was noted. Oral exam revealed intact hard and soft palates. Resting upper airway endoscopy via both nasal passages revealed normal nasal, pharyngeal, and laryngeal anatomy, with full abduction of the arytenoids. A moderate amount of lymphoid hyperplasia was present. An intraoral dorsoventral radiographic view of the rostral skull identified a 2-3mm area of increased lucency along the symphysis of the incisive bone (Fig 1).
AC C
3. Surgical Technique In preparation for surgery a complete blood count was performed, the results of which were within normal limits. An intravenous catheter was placed into the jugular vein and the foal was started on cefazolin (Cefazolin for injection)1 11 mg/kg bwt IV TID and gentamicin (GentaFuse)2 6.6 mg/kg bwt IV SID. Preoperatively the foal received one dose of intravenous flunixin meglumine (Flu-Nix)3 1.1 mg/kg bwt. The patient was induced under general anesthesia using midazolam (Midazolam Injection, USP)4 0.1 mg/kg bwt and ketamine (Ketathesia)5 2.3 mg/kg bwt and was maintained on isoflurane via nasotracheal tube. The patient was placed in dorsal recumbency and an oral endoscopic exam was performed and revealed no abnormalities of the soft or hard palate. The internal and external surfaces of the upper lip were clipped and prepared for surgery.
ACCEPTED MANUSCRIPT
M AN U
SC
RI PT
A diamond-shaped incision was made through the skin using a #15 blade (Fig 2). Two curvilinear incisions were made directed rostro-dorso-laterally from the upper labial frenulum to the mucocutaneous junction of each apex of the labia. These two divergent incisions were the directed axially back towards midline at the dorsal philtrum. Metzenbaum scissors were then used to deepen this incision and dissect between tissue planes exposing the broad abnormal aponeurosis of the orbicularis oris mm. Manual pressure and electrocautery were employed to control hemorrhage. The result was the removal of a full thickness diamond-shaped piece of tissue about 6 cm wide at the base down to the deep orbicularis oris mm. The mucosa was then undermined using a combination of blunt and sharp dissection to release tension on the tissue. The two separated ends of the orbicularis oris muscle were isolated as much as possible and the edges were abraded to stimulate bleeding. The oral mucosal defect was then joined to the opposite side with 2/0 polydioxanone (PDS)6 in a simple interrupted pattern beginning with a suture at the mucocutaneous junction. The subcutaneous space and muscle mass of the orbicularis oris was reconstructed with 0 polyglactin 910 (Vicryl)6 in a simple interrupted pattern. Vertical mattress sutures using 0 polydioxanone (PDS)6 with 3 mm plastic tubing stents were placed in the skin in an effort to relieve tension on the primary closure (Fig 3). The incision was covered in aluminum powder (AluSpray)7. The foal recovered without incident from anesthesia.
EP
TE D
4. Outcome The foal was maintained on intravenous antibiotics until she was discharged from the hospital two days following surgery. The foal was immediately able to nurse and prehend food easily after surgery. She was transitioned to oral sulfamethoxazole/trimethoprim (SMZ)8 30 mg/kg bwt q. 12 hrs until suture removal. The mare and foal were confined to a box stall for two weeks following surgery until the skin sutures were removed. No dehiscence occurred and the farm manager and race trainer reported excellent cosmesis; unfortunately, no photographs were obtained following suture removal (Fig 4). She went into race training as a two-year-old but never raced for reasons unrelated to the labial defect.
AC C
5. Discussion To the authors’ knowledge this is the first case report describing the correction of a cleft lip in a foal with no palatal abnormalities. Leipold and Dennis stated that congenital defects of the lips have not been described in horses [1]. While exceedingly rare, two separate case studies have been published documenting clefting in the lower lip and mandible of a donkey [2] and in the lower lip, mandible, and tongue of a foal [3]. The incidence of congenital abnormalities is difficult to assess as most cases reported are isolated and anecdotal. Of the congenital abnormalities in foals reported as case studies, approximately 4% of them are palatal defects [4]. The etiology of congenital defects in equids is poorly described but theories include compromised intrauterine environment, genetic abnormalities, and teratogen exposure [4]. There has been more research examining the genetics and the mode of inheritance of orofacial clefts in
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
cows than in horses. Two studies, in separate bovine family groups, have found that orofacial clefts, with a component of cheiloschisis, are inherited via an autosomal recessive pattern [5][6]. The breeding that resulted in the affected foal in this case report only occurred once, and the dam has had unaffected foals by other sires. In the human literature a specific locus, interferon regulatory factor 6, has been found to have an association with a wide range of orofacial clefting syndromes when mutated [7]. Other contributing factors to the development of cheiloschisis include gene-gene interactions in which genetic variation in more than one gene needs to occur to achieve the cleft lip phenotype and gene-environment interactions, in which genetic variation and maternal factors together contribute to the development of orofacial clefting. Spontaneous missense mutations have also been linked to the development of this phenotype [8]. Based on this research supporting a multifactorial etiology of orofacial clefting in humans, it is likely that cheiloschisis in horses is likewise obtained via a complicated and case-specific process. The surgical correction of cheiloschisis in equids is substantially easier than in humans for many reasons, including the absence of a delicately sculpted philtrum or the tissue between the nostrils and the lip margin, the tough nature of the tissue being manipulated, and the absence of any true fine motor skill in that area. The primary muscle that is affected by the repair is the levator labii superioris. This muscle originates from the maxilla, courses dorso-rostrally to travel between the nostrils, and inserts as a common tendon with its partner within the upper lip. This muscle is responsible for the Flehmen response [9]. It would be interesting to know if this behavior is possible following correction of this kind. The other muscles that exist in this area and allow the horse to have prehensile lips are the orbicularis oris, which runs parallel to the lip margin and serves to purse the lips, and the incisivis superioris, which runs parallel to the incisors. These are difficult to distinguish during surgery as the connective tissues, subcutaneous tissues and skin are closely adhered to the muscles. The upper lip is innervated by the dorsal buccal branch of the facial nerve for motor function and the maxillary branch of the trigeminal nerve for sensory function. As neither of these nerves have major components at the area of resection, nerve damage following the procedure was not a major concern [10]. It should be noted that this case of cheiloschisis was not life threatening, as the foal was able to nurse and eat solid food without issue, and no palatal abnormalities were present. Surgical correction was driven by owner desire for a sales prospect which, reportedly, was not pursued for reasons other than the cleft lip. 6. Conclusion This case study demonstrates that it is possible to surgically treat a cleft lip in a horse, and that a horse affected with cheiloschisis can prehend food, drink water, nurse normally, and go on to participate in race training following surgical repair. The author believes that it is impossible to make breeding recommendations based on one case when the mode of inheritance is so poorly understood.
ACCEPTED MANUSCRIPT
Sources of Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
RI PT
Conflicts of Interest None of the authors have any conflicts of interest to declare for this paper.
References
TE D
M AN U
Manufacturers’ addresses’ 1. WG Critical Care LLC, Paramus NJ, 07652 USA 2. Sparhawk Laboratories Inc., Lenexa KS, 66215 USA 3. Agri Laboratories Ltd., St. Joseph MO, 64503 USA 4. Akorn, Inc., Lake Forest IL, 60045 5. Henry Schein Animal Health, Dublin OH, 43017 6. Ethicon LLC, Guaynabo Puerto Rico, 00969 7. Neogen Corporation, Lexington KY, 40511 USA 8. Amneal Pharmaceuticals, Bridgewater NJ, 08807
SC
Acknowledgements The authors would like to thank all the staff at Rhinebeck Equine for helping with the care of this horse during its hospitalization.
EP
[1] Leipold HW, Dennis SM. (1993) Congenital defects in foals. In: Equine Reproduction. 1st edn., Ed: AO McKinnon, JL Voss, Williams & Willikins, Baltimore USA. pp 604-613.
AC C
[2] Farmand M, Stohler T. (1990) The median cleft of the lower lip and mandible and its surgical correction in a donkey. Equine Vet. J., 22, 298-301. [3] Aksoy O, Kilic E, Kacar C, Sozmen M, Gokhan N, & Gungor O. (2007) Congenital glossocheilognathoschisis and persistent frenula linguae in a foal: a case report. J. Equine Vet Sci., 27, 277-280. [4] Cruz AM. (2011) Congenital problems of foals. In: Equine Reproduction. 2nd edn., Ed: A. O. McKinnon, E. L. Squires, W. E. Vaala, & D. D. Varner, (Eds.). John Wiley & Sons, West Sussex UK 663-672. [5] Lupp B, Reinhardt M, Maus F, Hellige M, Feige K, & Distl O. (2012) Right-sided cleft lip and jaw in a family of Vorderwald× Montbéliarde cattle. Vet. J. 192, 520-522.
ACCEPTED MANUSCRIPT
[6] Rieke H. (1982) Die Gesichtsspalten (Cheilognathoschisis und Palatoschisis) in der hessischen Rinderpopulation. Morphologie, Aetiologie, Statistik. Dissertation, Justus-LiebigUniversität Gießen.
SC
RI PT
[7] Zucchero TM, Cooper ME, Maher BS, Daack-Hirsch, S, Nepomuceno, B., Ribeiro, L., Caprau, D., Christensen, K., Suzuki, Y., Machida, J., Natsume, N., Yoshiura, K., Vieira, A. R., Orioli, I. M., Castilla, E. E., Moreno, L., Arcos-Burgos, M., Lidral, A. C., Field, L., Liu, Y., Ray, A., Goldstein, T. H., Schultz, R. E., Shi, M., Johnson, M. K., Kondo, S., Schutte, B. C., Marazita, M. L., and Murray, J. C. (2004) Interferon regulatory factor 6 (IRF6) gene variants and the risk of isolated cleft lip or palate. New Engl. J. Med., 351, 769-780.
M AN U
[8] Vieira, A. R. (2008) Unraveling human cleft lip and palate research. J. Dent. Res., 87, 119125. [9] Dyce, K. M., Sack, W. O., & Wensing, C. J. G. (2009) The head and ventral neck of the horse. Textbook of veterinary anatomy. 4th edn., Elsevier Health Sciences, St. Louis, Missouri. (501-515).
AC C
EP
TE D
[10] Tremaine, W. H. (1998) Management of equine mandibular injuries. Equine Vet. Educ., 10, 146-154.
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 1: Intraoral radiograph of the incisive bone showing the diastema between the left and right first incisors.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 2: Proposed line of dissection prior to surgical correction of cleft lip.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 3: The cleft lip reconstruction procedure. a) The cleft lip with concurrent robust frenulum, and diastema between first incisors prior to surgery. b) A wedge shaped incision was made through the abnormal axial tissue. c) Following dissection the subcuticular and muscular layers are visible. d) The mucosal layers are brought into apposition. e) Surgery site following subcuticular and muscle reconstruction suture placement. f) Result of tension relieving vertical mattress stent sutures showing establishment of normal lip anatomy.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 4: Before and after surgical resolution of a cleft lip.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal Highlights
AC C
EP
TE D
M AN U
SC
RI PT
- Documenting a case of cleft lip in a thoroughbred foal with no palatal abnormalities. - Successful surgical repair of cleft lip. - Discussion of breeding ethics in horses with cosmetic orofacial defects. - Race training possible after cheiloschisis repair.
S0737-0806(17)30400-8
DOI:
10.1016/j.jevs.2017.07.006
Reference:
YJEVS 2351
To appear in:
Journal of Equine Veterinary Science
Received Date: 20 April 2017 Revised Date:
21 July 2017
Accepted Date: 23 July 2017
Please cite this article as: Watkins A, Abuja G, Javsicas L, Nutt J IV, Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal, Journal of Equine Veterinary Science (2017), doi: 10.1016/ j.jevs.2017.07.006. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal
SC
TE D
Laura Javsicas VMD DACVIMa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
M AN U
Gustavo Abuja DVM DACVSa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
RI PT
Amanda Watkins VMDa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
AC C
EP
James Nutt IV VMD DACVSa a Rhinebeck Equine LLP 26 Losee Lane Rhinebeck, NY 12572 PH: 845-876-7085 Fax: 845- 876-8611 [email protected]
Please direct correspondence to: James Nutt Rhinebeck Equine L.L.P. 26 Losee Lane Rhinebeck, NY 12572
ACCEPTED MANUSCRIPT
RI PT
Abstract This report describes the clinical findings and surgical treatment of a foal with cheiloschisis or cleft lip. Physical exam revealed a diastema between the two first incisors and a robust frenulum in addition to the wide, bi-partite upper lip. Radiographic exam revealed a 2-3 mm area of increased lucency widening the symphysis of the incisive bone, but no other defects of the hard palate. Resting endoscopic exam of the upper respiratory tract was unremarkable. The sagittal area of clefting was removed and the two cut margins were brought together to form a normal lip. The foal recovered well and went on to race training as a two year-old.
SC
Keywords: cleft, lip, surgery, repair, horse, equine
M AN U
1. Case History A 4-month old, 140kg, Thoroughbred filly was presented to the clinic for the evaluation and surgical correction of a congenital cleft upper lip or cheiloschisis. The filly was able to nurse, prehend food with some difficulty, and was a 5/9 body condition score on arrival. The lip was grossly abnormal from birth. Surgical correction was desired to prepare the horse for possible sale and race training.
EP
TE D
2. Clinical Findings On presentation the dorsal lip was wide and flat with a cleft area on midline. An abnormally robust frenulum was present on midline connecting the gingiva to the buccal mucosa. A diastema between the left and right first incisors (Triadan 101 and 201) was noted. Oral exam revealed intact hard and soft palates. Resting upper airway endoscopy via both nasal passages revealed normal nasal, pharyngeal, and laryngeal anatomy, with full abduction of the arytenoids. A moderate amount of lymphoid hyperplasia was present. An intraoral dorsoventral radiographic view of the rostral skull identified a 2-3mm area of increased lucency along the symphysis of the incisive bone (Fig 1).
AC C
3. Surgical Technique In preparation for surgery a complete blood count was performed, the results of which were within normal limits. An intravenous catheter was placed into the jugular vein and the foal was started on cefazolin (Cefazolin for injection)1 11 mg/kg bwt IV TID and gentamicin (GentaFuse)2 6.6 mg/kg bwt IV SID. Preoperatively the foal received one dose of intravenous flunixin meglumine (Flu-Nix)3 1.1 mg/kg bwt. The patient was induced under general anesthesia using midazolam (Midazolam Injection, USP)4 0.1 mg/kg bwt and ketamine (Ketathesia)5 2.3 mg/kg bwt and was maintained on isoflurane via nasotracheal tube. The patient was placed in dorsal recumbency and an oral endoscopic exam was performed and revealed no abnormalities of the soft or hard palate. The internal and external surfaces of the upper lip were clipped and prepared for surgery.
ACCEPTED MANUSCRIPT
M AN U
SC
RI PT
A diamond-shaped incision was made through the skin using a #15 blade (Fig 2). Two curvilinear incisions were made directed rostro-dorso-laterally from the upper labial frenulum to the mucocutaneous junction of each apex of the labia. These two divergent incisions were the directed axially back towards midline at the dorsal philtrum. Metzenbaum scissors were then used to deepen this incision and dissect between tissue planes exposing the broad abnormal aponeurosis of the orbicularis oris mm. Manual pressure and electrocautery were employed to control hemorrhage. The result was the removal of a full thickness diamond-shaped piece of tissue about 6 cm wide at the base down to the deep orbicularis oris mm. The mucosa was then undermined using a combination of blunt and sharp dissection to release tension on the tissue. The two separated ends of the orbicularis oris muscle were isolated as much as possible and the edges were abraded to stimulate bleeding. The oral mucosal defect was then joined to the opposite side with 2/0 polydioxanone (PDS)6 in a simple interrupted pattern beginning with a suture at the mucocutaneous junction. The subcutaneous space and muscle mass of the orbicularis oris was reconstructed with 0 polyglactin 910 (Vicryl)6 in a simple interrupted pattern. Vertical mattress sutures using 0 polydioxanone (PDS)6 with 3 mm plastic tubing stents were placed in the skin in an effort to relieve tension on the primary closure (Fig 3). The incision was covered in aluminum powder (AluSpray)7. The foal recovered without incident from anesthesia.
EP
TE D
4. Outcome The foal was maintained on intravenous antibiotics until she was discharged from the hospital two days following surgery. The foal was immediately able to nurse and prehend food easily after surgery. She was transitioned to oral sulfamethoxazole/trimethoprim (SMZ)8 30 mg/kg bwt q. 12 hrs until suture removal. The mare and foal were confined to a box stall for two weeks following surgery until the skin sutures were removed. No dehiscence occurred and the farm manager and race trainer reported excellent cosmesis; unfortunately, no photographs were obtained following suture removal (Fig 4). She went into race training as a two-year-old but never raced for reasons unrelated to the labial defect.
AC C
5. Discussion To the authors’ knowledge this is the first case report describing the correction of a cleft lip in a foal with no palatal abnormalities. Leipold and Dennis stated that congenital defects of the lips have not been described in horses [1]. While exceedingly rare, two separate case studies have been published documenting clefting in the lower lip and mandible of a donkey [2] and in the lower lip, mandible, and tongue of a foal [3]. The incidence of congenital abnormalities is difficult to assess as most cases reported are isolated and anecdotal. Of the congenital abnormalities in foals reported as case studies, approximately 4% of them are palatal defects [4]. The etiology of congenital defects in equids is poorly described but theories include compromised intrauterine environment, genetic abnormalities, and teratogen exposure [4]. There has been more research examining the genetics and the mode of inheritance of orofacial clefts in
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
cows than in horses. Two studies, in separate bovine family groups, have found that orofacial clefts, with a component of cheiloschisis, are inherited via an autosomal recessive pattern [5][6]. The breeding that resulted in the affected foal in this case report only occurred once, and the dam has had unaffected foals by other sires. In the human literature a specific locus, interferon regulatory factor 6, has been found to have an association with a wide range of orofacial clefting syndromes when mutated [7]. Other contributing factors to the development of cheiloschisis include gene-gene interactions in which genetic variation in more than one gene needs to occur to achieve the cleft lip phenotype and gene-environment interactions, in which genetic variation and maternal factors together contribute to the development of orofacial clefting. Spontaneous missense mutations have also been linked to the development of this phenotype [8]. Based on this research supporting a multifactorial etiology of orofacial clefting in humans, it is likely that cheiloschisis in horses is likewise obtained via a complicated and case-specific process. The surgical correction of cheiloschisis in equids is substantially easier than in humans for many reasons, including the absence of a delicately sculpted philtrum or the tissue between the nostrils and the lip margin, the tough nature of the tissue being manipulated, and the absence of any true fine motor skill in that area. The primary muscle that is affected by the repair is the levator labii superioris. This muscle originates from the maxilla, courses dorso-rostrally to travel between the nostrils, and inserts as a common tendon with its partner within the upper lip. This muscle is responsible for the Flehmen response [9]. It would be interesting to know if this behavior is possible following correction of this kind. The other muscles that exist in this area and allow the horse to have prehensile lips are the orbicularis oris, which runs parallel to the lip margin and serves to purse the lips, and the incisivis superioris, which runs parallel to the incisors. These are difficult to distinguish during surgery as the connective tissues, subcutaneous tissues and skin are closely adhered to the muscles. The upper lip is innervated by the dorsal buccal branch of the facial nerve for motor function and the maxillary branch of the trigeminal nerve for sensory function. As neither of these nerves have major components at the area of resection, nerve damage following the procedure was not a major concern [10]. It should be noted that this case of cheiloschisis was not life threatening, as the foal was able to nurse and eat solid food without issue, and no palatal abnormalities were present. Surgical correction was driven by owner desire for a sales prospect which, reportedly, was not pursued for reasons other than the cleft lip. 6. Conclusion This case study demonstrates that it is possible to surgically treat a cleft lip in a horse, and that a horse affected with cheiloschisis can prehend food, drink water, nurse normally, and go on to participate in race training following surgical repair. The author believes that it is impossible to make breeding recommendations based on one case when the mode of inheritance is so poorly understood.
ACCEPTED MANUSCRIPT
Sources of Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
RI PT
Conflicts of Interest None of the authors have any conflicts of interest to declare for this paper.
References
TE D
M AN U
Manufacturers’ addresses’ 1. WG Critical Care LLC, Paramus NJ, 07652 USA 2. Sparhawk Laboratories Inc., Lenexa KS, 66215 USA 3. Agri Laboratories Ltd., St. Joseph MO, 64503 USA 4. Akorn, Inc., Lake Forest IL, 60045 5. Henry Schein Animal Health, Dublin OH, 43017 6. Ethicon LLC, Guaynabo Puerto Rico, 00969 7. Neogen Corporation, Lexington KY, 40511 USA 8. Amneal Pharmaceuticals, Bridgewater NJ, 08807
SC
Acknowledgements The authors would like to thank all the staff at Rhinebeck Equine for helping with the care of this horse during its hospitalization.
EP
[1] Leipold HW, Dennis SM. (1993) Congenital defects in foals. In: Equine Reproduction. 1st edn., Ed: AO McKinnon, JL Voss, Williams & Willikins, Baltimore USA. pp 604-613.
AC C
[2] Farmand M, Stohler T. (1990) The median cleft of the lower lip and mandible and its surgical correction in a donkey. Equine Vet. J., 22, 298-301. [3] Aksoy O, Kilic E, Kacar C, Sozmen M, Gokhan N, & Gungor O. (2007) Congenital glossocheilognathoschisis and persistent frenula linguae in a foal: a case report. J. Equine Vet Sci., 27, 277-280. [4] Cruz AM. (2011) Congenital problems of foals. In: Equine Reproduction. 2nd edn., Ed: A. O. McKinnon, E. L. Squires, W. E. Vaala, & D. D. Varner, (Eds.). John Wiley & Sons, West Sussex UK 663-672. [5] Lupp B, Reinhardt M, Maus F, Hellige M, Feige K, & Distl O. (2012) Right-sided cleft lip and jaw in a family of Vorderwald× Montbéliarde cattle. Vet. J. 192, 520-522.
ACCEPTED MANUSCRIPT
[6] Rieke H. (1982) Die Gesichtsspalten (Cheilognathoschisis und Palatoschisis) in der hessischen Rinderpopulation. Morphologie, Aetiologie, Statistik. Dissertation, Justus-LiebigUniversität Gießen.
SC
RI PT
[7] Zucchero TM, Cooper ME, Maher BS, Daack-Hirsch, S, Nepomuceno, B., Ribeiro, L., Caprau, D., Christensen, K., Suzuki, Y., Machida, J., Natsume, N., Yoshiura, K., Vieira, A. R., Orioli, I. M., Castilla, E. E., Moreno, L., Arcos-Burgos, M., Lidral, A. C., Field, L., Liu, Y., Ray, A., Goldstein, T. H., Schultz, R. E., Shi, M., Johnson, M. K., Kondo, S., Schutte, B. C., Marazita, M. L., and Murray, J. C. (2004) Interferon regulatory factor 6 (IRF6) gene variants and the risk of isolated cleft lip or palate. New Engl. J. Med., 351, 769-780.
M AN U
[8] Vieira, A. R. (2008) Unraveling human cleft lip and palate research. J. Dent. Res., 87, 119125. [9] Dyce, K. M., Sack, W. O., & Wensing, C. J. G. (2009) The head and ventral neck of the horse. Textbook of veterinary anatomy. 4th edn., Elsevier Health Sciences, St. Louis, Missouri. (501-515).
AC C
EP
TE D
[10] Tremaine, W. H. (1998) Management of equine mandibular injuries. Equine Vet. Educ., 10, 146-154.
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 1: Intraoral radiograph of the incisive bone showing the diastema between the left and right first incisors.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 2: Proposed line of dissection prior to surgical correction of cleft lip.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 3: The cleft lip reconstruction procedure. a) The cleft lip with concurrent robust frenulum, and diastema between first incisors prior to surgery. b) A wedge shaped incision was made through the abnormal axial tissue. c) Following dissection the subcuticular and muscular layers are visible. d) The mucosal layers are brought into apposition. e) Surgery site following subcuticular and muscle reconstruction suture placement. f) Result of tension relieving vertical mattress stent sutures showing establishment of normal lip anatomy.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
AC C
EP
TE D
M AN U
SC
RI PT
Fig 4: Before and after surgical resolution of a cleft lip.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
Cheiloschisis: Surgical Repair of Cleft Lip in a Thoroughbred Foal Highlights
AC C
EP
TE D
M AN U
SC
RI PT
- Documenting a case of cleft lip in a thoroughbred foal with no palatal abnormalities. - Successful surgical repair of cleft lip. - Discussion of breeding ethics in horses with cosmetic orofacial defects. - Race training possible after cheiloschisis repair.