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Video-assisted unilateral cricoarytenoid laryngoplasty in 14 dogs with bilateral idiopathic laryngeal paralysis a

b

b

Laura C. Cuddy , J. Brad Case , Gary W. Ellison & Jennifer L. Covey

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Department of Surgery, Section of Veterinary Clinical Studies, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Ireland b

Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA c

Pittsburgh Veterinary Specialty & Emergency Centre, 807 Camp Horne Road, Pittsburgh, PA, 15237, USA Accepted author version posted online: 10 Dec 2013.Published online: 10 Jan 2014.

To cite this article: Laura C. Cuddy, J. Brad Case, Gary W. Ellison & Jennifer L. Covey (2013) Video-assisted unilateral cricoarytenoid laryngoplasty in 14 dogs with bilateral idiopathic laryngeal paralysis , Veterinary Quarterly, 33:4, 181-185, DOI: 10.1080/01652176.2013.873962 To link to this article: http://dx.doi.org/10.1080/01652176.2013.873962

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Veterinary Quarterly, 2013 Vol. 33, No. 4, 181–185, http://dx.doi.org/10.1080/01652176.2013.873962

ORIGINAL ARTICLE Video-assisted unilateral cricoarytenoid laryngoplasty in 14 dogs with bilateral idiopathic laryngeal paralysis1 Laura C. Cuddya, J. Brad Caseb*, Gary W. Ellisonb and Jennifer L. Coveyc a Department of Surgery, Section of Veterinary Clinical Studies, School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Ireland; bDepartment of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA; cPittsburgh Veterinary Specialty & Emergency Centre, 807 Camp Horne Road, Pittsburgh, PA, 15237, USA

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(Received 30 October 2013; accepted 7 December 2013) Background: Unilateral cricoarytenoid laryngoplasty is commonly performed for treatment of idiopathic laryngeal paralysis in dogs. Determination of the appropriate tension applied to the suture can be difficult, particularly for the novice surgeon. Objective: To describe a technique for video-assisted unilateral cricoarytenoid laryngoplasty (VAUCAL) and to report short-term outcome in dogs undergoing VAUCAL. Animals and methods: Dogs (n ¼ 14) with bilateral idiopathic laryngeal paralysis undergoing VAUCAL between August 2011 and May 2013 were evaluated. A cricoarytenoid suture was tensioned under video observation of the rima glottidis using a 5-mm rigid endoscope. Real-time visualization of arytenoid abduction during suture tensioning, and final arytenoid position were assessed. Requirement for additional intravenous anesthestic, intra- and post-operative complications and short-term outcomes were documented. Results: Adequate, real-time visualization of the larynx during tensioning of the cricoarytenoid suture was accomplished in 13/14 dogs. Additional intravenous anesthesia was required in 5/14 dogs to facilitate reintubation. Final arytenoid position was considered inadequate in two dogs on post-operative trans-oral laryngeal examination. Recurrence of clinical signs occurred in one dog three months following initial surgery. Owner outcome was deemed good (n ¼ 8) or excellent (n ¼ 6). Conclusions: VAUCAL is a feasible technique to permit direct real-time visualization of the larynx during tensioning of the cricoarytenoid suture, and enables assessment of final arytenoid position intra-operatively by the operating surgeon. Clinical importance: VAUCAL allows the operating surgeon to assess arytenoid abduction intra-operatively, at the time of knot placement. This technique may be particularly useful for the novice surgeon or surgeon in training. Keywords: dog; canine; laryngeal paralysis; video-assisted; cricoarytenoid laryngoplasty

1. Introduction Acquired bilateral idiopathic laryngeal paralysis is a common condition in older, large-breed dogs that may result in exercise intolerance, stridor, respiratory distress, and death (Monnet & Tobias 2012). While many surgical techniques have been described to treat bilateral idiopathic laryngeal paralysis (Lozier & Pope 1982; Rosin & Greenwood 1982; White 1989; Burbidge et al. 1993; Lussier et al. 1996; Griffiths et al. 2001; MacPhail & Monnet 2001; Bureau & Monnet 2002; Demetriou & Kirby 2003; Hammel et al. 2006; Greenberg et al. 2007; Schofield et al. 2007; Olivieri et al. 2009; Monnet & Tobias 2012), debate still exists as to the superiority of one method over another. The procedure performed most commonly at our institution is unilateral cricoarytenoid laryngoplasty (UCAL) under low tension (Bureau & Monnet 2002; Greenberg et al. 2007). Cadaveric studies have demonstrated that UCAL provides increased percentage increase in rima glottidis surface area (Lussier et al. 1996; Griffiths et al. 2001; Wignall & Baines 2012) and decreased airway resistance (Wignall & Baines 2012)

compared with unilateral thyroarytenoid laryngoplasty. Changes in airway resistance following combined unilateral crico- and thyroarytenoid laryngoplasty have been shown to be comparable to unilateral cricoarytenoid laryngoplasty (Wignall & Baines 2012). The presence of concurrent esophageal dysmotility complicates surgical intervention due to the increased risk of aspiration pneumonia following arytenoid laryngoplasty (Stanley et al. 2010). Post-operative aspiration pneumonia has been reported in 10.0%–23.6% of dogs following UCAL (White 1989; MacPhail & Monnet 2001; Hammel et al. 2006; Stanley et al. 2010). In UCAL, full tensioning of the suture is not desired, due to the potential for overabduction of the arytenoid cartilage and the subsequent inability of the epiglottis to protect the airway during swallowing (Bureau & Monnet 2002; Greenberg et al. 2007), particularly in dogs with concurrent esophageal dysfunction. Conversely, too little abduction will result in persistence of clinical signs. The optimum amount of arytenoid abduction or increase in rima glottidis area is unknown in dogs (Bureau & Monnet

1 Research conducted at the Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA. Abstract presented in part at the Veterinary Endoscopy Society 9th Annual Meeting, March 22–24, 2012, Park City, Utah.

*Corresponding author. Email: [email protected] Ó 2014 Taylor & Francis

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2002; Greenberg et al. 2007; Weinstein & Weisman 2010). Many surgeons aim to subjectively increase the area of the rima glottidis, while others recommend abduction based on limited dissection of the cricoarytenoid joint and low tension placed on the lateralizing cricoarytenoid suture. For the novice surgeon, in particular, it may be challenging to accurately apply consistent tension for the desired arytenoid abduction when the suture is tensioned and secured blindly. Techniques described to assess arytenoid abduction include post-operative trans-oral laryngoscopy by the surgeon (White 1989), intra-operative trans-oral laryngoscopy by an assistant (Weinstein & Weisman 2010), and post-operative endoscopic laryngoscopy by the surgeon (Griffiths et al. 2001). Intra-operative trans-oral laryngoscopy is the technique of choice of most surgeons; however, this technique is potentially inconvenient for a number of reasons (Weinstein & Weisman 2010). If the operating surgeon performs the assessment, they may have to re-sterilize to complete the procedure following laryngoscopy. This may prolong anesthesia and surgery time, requires additional sterile supplies such as gowns and gloves, and may risk contamination of the surgical field. If a surgical assistant performs the assessment, there may be difference of opinion regarding the adequacy of arytenoid abduction. If arytenoid abduction is either inadequate or excessive, revision surgery may be required (Hammel et al. 2006). Revision surgery increases anesthetic and surgical time, as well as cost to the client and hospital, and may increase the risk of complications. These factors considered, the surgeon may be inclined to accept the degree of abduction rather than to revise it to the intended position. Given the potential for inconsistency in degree of arytenoid abduction and potential limitations of current methods of assessing arytenoid abduction, we aimed to determine if video-assisted unilateral cricoarytenoid laryngoplasty (VAUCAL) could be accomplished in dogs with acquired bilateral idiopathic laryngeal paralysis using a rigid endoscope. The objectives of this study were to investigate the feasibility and describe the complications and short-term outcome associated with VAUCAL. We hypothesized that VAUCAL would provide direct visualization of the larynx by the primary surgeon, would enable real-time assessment of laryngeal abduction during suture tensioning, and permit evaluation of arytenoid position at the time of knot tying. 2. Materials and methods Dogs that underwent VAUCAL between August 2011 and May 2013 were evaluated. Cases were included in the study if they had no identifiable underlying cause for laryngeal paralysis (idiopathic), or underlying cardiovascular disease, had trans-oral laryngoscopy to confirm bilateral idiopathic laryngeal paralysis, and if they subsequently underwent VAUCAL. Post-operative trans-oral laryngoscopy was performed following VAUCAL in the initial five dogs.

Signalment (age, sex, breed, and body weight) and clinical signs present at the time of initial evaluation were recorded. Pre-operative diagnostic evaluation included complete blood count, serum chemistry, total thyroid level, urinalysis, and thoracic radiographs. 2.1.

Pre-operative laryngeal examination

Standard trans-oral laryngoscopy was performed in sternal recumbency under a light plane of anesthesia prior to surgery in all dogs (Monnet & Tobias 2012). Propofol (PropoFlo, Abbot Laboratories, Abbot Park, Ill, USA) was administered (2 mg/kg BW IV to effect) and titrated to achieve a plane of anesthesia which allowed conscious respiration and concurrent visualization of the larynx. Results of the trans-oral laryngoscopic examination were noted in the medical records. Patients were classified as having bilateral laryngeal paralysis if no abduction of the arytenoid cartilages was present during inspiration. 2.2. Surgical procedure All procedures were performed by a Diplomate of the American College of Veterinary Surgeons or a surgical resident under their direct supervision. Dogs were placed in right lateral recumbency with the tip of the nose at the foremost edge of the operating table during the surgical procedure. An endoscopic tower with video monitor was positioned opposite the surgeon, towards the head of the patient. A standard lateral approach to the left cricoarytenoid joint was performed (Monnet & Tobias 2012). The cricoarytenoid articulation was opened caudally and dissected minimally to visualize the cricoarytenoid articular surface. In nine dogs, two interrupted sutures were placed from the caudodorsal aspect of the cricoid cartilage through the muscular process of the arytenoid cartilage, (n ¼ 7) using 2-0 polypropylene (ProleneTM, Ethicon, Somerville, NJ, USA), (n ¼ 1) 0 polypropylene (ProleneTM) and (n ¼ 1) 2-0 polybutester (NovafilTM, Covidien, Mansfield, MA, USA). In five dogs, a single suture was placed (n ¼ 2) using 2-0 polypropylene (ProleneTM), (n ¼ 2) 2-0 polybutester (NovafilTM), and (n ¼ 1) 0-polypropylene (ProleneTM). Once the suture (or initial suture in the case of the dogs with two sutures) was placed, a loose slip knot was formed with no tension applied. 2.3.

VAUCAL

Once the slip knot was positioned, a dental mouth gag was placed between the right canine teeth to maintain an open jaw during the VAUCAL procedure. A 5 mm, 0 (5-mm diameter 0 Hopkins II telescope, Karl Storz, Veterinary Endoscopy, Goleta, CA, USA) (n ¼ 13), or 30 (5-mm diameter 30 Hopkins II telescope, Karl Storz, Veterinary Endoscopy) (n ¼ 1) telescope was slowly advanced transorally to the caudal edge of the soft palate using the endotracheal tube as a guide. The dog was extubated to visualize the larynx and the camera head or light post was rotated 90 to create a dorsal-to-ventral view of the larynx on the video monitor. The slip knot was then tensioned by the

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operating surgeon under video observation of the larynx. Adequate abduction of the arytenoid cartilage was determined by the surgeon visualizing the larynx on the video monitor, and the knot was secured (Figure 1). Adequate lateralization was defined as a subjective increase in the rima glottidis diameter by abduction of the left arytenoid without medialization of the right arytenoid or rotation of the larynx. The telescope was removed and the dog was then reintubated. For the last 10 cases, the endoscope was used to guide placement of the endotracheal tube following VAUCAL. The surgical site was lavaged and closed routinely (Monnet & Tobias 2012). Surgical time was recorded in the anesthetic record and was defined as the time from the initial skin incision to the time of skin closure. 2.4. Outcome measures The following factors were documented: adequate visualization of the larynx (yes/no), real-time evaluation of cricoarytenoid abduction during suture tensioning (yes/no), and subjective adequate cricoarytenoid abduction at the time of knot placement (yes/no). Extubation time and the need for additional intravenous anesthetics were retrieved from the anesthetic record. Intra-operative as well as early and late post-operative complications were documented. Post-operative trans-oral laryngoscopy was repeated at the time of extubation to confirm adequate abduction of the arytenoid cartilage in the first five dogs. 2.5.

Follow-up evaluation

All cases presented for recheck examination at suture removal between 10 and 14 days post-operatively, either

Figure 1. Intraoperative image of the larynx of a dog included in this study after VAUCAL.

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to the University Small Animal Hospital or to the referring veterinarian. Owners were asked to subjectively grade improvement of clinical signs related to the airway as excellent, good, equivocal, or worse. Follow-up phone calls were made to the owner at the time of manuscript preparation to assess short-term outcome.

2.6. Statistical methods Data was stored and analyzed using commercially available statistical software (JMP 9.0 (SAS InstituteÓ 2011), Cary, NC, USA). Continuous, normally distributed data were reported as means  standard deviation. Nonparametric continuous data was reported as median and range.

3. Results A total of 14 dogs were included in this study. Of these, eight were spayed females and six were castrated males. The mean age at presentation was 11.5  3.0 years. The mean body weight was 29.4  8.4 kg. Breeds represented were Labrador retrievers or crosses (n ¼ 9), Brittany Spaniel (n ¼ 1), Cocker Spaniel (n ¼ 1), Greyhound (n ¼ 1), and mixed breed dogs (n ¼ 2). Clinical signs reported by the owners at the time of presentation included the following: inspiratory noise/stridor (n ¼ 11), exercise intolerance (n ¼ 9), gagging (n ¼ 6), coughing (n ¼ 3), bark change (n ¼ 3), episodic cyanosis (n ¼ 2), and pelvic limb weakness (n ¼ 1). Pertinent physical exam findings included the following: stridor (n ¼ 14), dyspnea (n ¼ 7), conscious proprioceptive deficits (n ¼ 9), and tachycardia (n ¼ 2). Abnormalities noted on initial thoracic radiographs included the following: unstructured interstitial pattern in the cranial lung lobes consistent with aspiration pneumonia (n ¼ 2), diffuse bronchial pulmonary pattern (n ¼ 2), unstructured interstitial pattern in the caudal lung lobes consistent with noncardiogenic pulmonary edema (n ¼ 1), and persistent mild gas distension in the esophagus (n ¼ 1). Barium esophograms were performed in two dogs, which revealed mild esophageal dysmotility in both dogs. On complete blood count, four dogs had thrombocytosis (mean 458  49.1  109/L) and one dog was thrombocytopenic (85  109/L). No other significant abnormalities were noted on complete blood count. On serum chemistry, seven dogs had mild elevations in serum alkaline phosphatase activity (mean 237  110 IU/L, reference interval 8–114) and one dog had significant elevation in serum alkaline phosphatase activity (4182 IU/L, reference interval 8–114). Five dogs had mild elevations in alanine aminotransferase activity (163  76 IU/L, reference interval 22–68). Four dogs had mild elevations in aspartate aminotransferase activity (93  43 IU/L, reference interval 15–52). Four dogs were mildly hypoalbuminemic (24  3.0 g/L, reference interval 29–38). Total thyroid concentration was within reference interval for all eight dogs for which measurements were available (mean 19  6.0 nmol/L, reference interval 8.0–45). No other significant abnormalities were noted on serum chemistry.

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All dogs were diagnosed as having bilateral idiopathic laryngeal paralysis based on clinical examination and preoperative trans-oral laryngoscopic evaluation. Initial visualization of the larynx, with adequate realtime evaluation of cricoarytenoid abduction during suture tensioning and knot placement was performed successfully in 13 of the 14 dogs. Real-time evaluation was not achieved in the first dog in the series due to inability to position the rigid telescope appropriately during suture tensioning. For this dog, a moderately tensioned suture was placed and the position of the arytenoid cartilage confirmed intra-operatively using a hand-held laryngoscope. For the remaining 13 dogs, a 5 mm, 0 rigid telescope was used. Mean surgical time for all cases was 81.3  31.7 minutes. Although the exact time required for VAUCAL was not documented in the anesthesia records, intra-operative extubation was less than 5 minutes for all cases. Subjectively, extubation time was less than 2 minutes for most cases. Six of 14 cases required additional intravenous administration of propofol (mean 0.76 mg/kg BW, range 0.57–1.43) to facilitate reintubation. Intraoperative complications occurred in four cases. These included an obscured view of the larynx due to an elongated soft palate (n ¼ 1), loss of arytenoid abduction between knot tying and extubated trans-oral laryngeal exam (n ¼ 2), and penetration of the oropharyngeal cavity during the surgical approach (n ¼ 1). In the two dogs in which the arytenoid was deemed inadequately abducted on post-operative trans-oral laryngeal exam, a loose suture was identified and revised immediately. Early post-operative complications included seroma formation (n ¼ 1) and iatrogenic atypical Addison’s disease from acute corticosteroid withdrawal (n ¼ 1). Late post-operative complications included recurrence of clinical signs three months post-operativly (n ¼ 1), aspiration pneumonia 10 months post-operatively (n ¼ 1), and significant progression of neurologic deficits 19 months post-operatively (n ¼ 1). In the case with recurrent clinical signs three months post-operatively, the owners reported initial resolution of respiratory dyspnea. The recurrent respiratory noise and exercise intolerance were considered mild compared to pre-operative signs and follow-up evaluation was declined by the owners. Thirteen of 14 dogs were alive at the time of last follow-up (median 88; range 14–585 days). One dog died from pulmonary thromboembolism as a complication of immune-mediated hemolytic anemia 359 days postoperatively. Complete resolution of pre-operative respiratory signs occurred following surgery in all but one dog who the owner estimated was 70% improved. All six dogs with pre-operative gagging continued to have intermittent gagging following surgery. Owner-assigned outcome was reported as good (n ¼ 8) and excellent (n ¼ 6) for resolution of respiratory signs. 4. Discussion VAUCAL appears to be a safe and effective method for direct visualization of the larynx during tensioning of a

cricoarytenoid suture, as well as final assessment of arytenoid position intra-operatively by the operating surgeon. Although two dogs in this series required immediate revision laryngoplasty, this complication was attributed to residual slack left in the suture line as opposed to failure of the reported technique. Dogs in this study were of similar breed and age as those in previous studies, with geriatric Labrador Retrievers represented most commonly (White 1989; Burbidge et al. 1993; MacPhail & Monnet 2001; Hammel et al. 2006; Stanley et al. 2010; Monnet & Tobias 2012). Clinical signs were consistent with those reported previously, with dyspnea and gagging being reported most commonly (Monnet & Tobias 2012). Neurologic examination findings in three dogs revealed evidence of possible underlying neurologic dysfunction supporting the assertions of previous reports where up to 31% of dogs demonstrated conscious proprioceptive deficits (Burbidge et al. 1993; Stanley et al. 2010) at the time of presentation. Furthermore, thoracic radiographic findings in two dogs and esophagrams in two dogs identified suspected esophageal dysfunction, previously purported to be associated with pararecurrent laryngeal nerve axonpathy (Stanley et al. 2010). Total thyroid levels were within reference interval for the nine dogs for which measurements were available, consistent with a previous report (Stanley et al. 2010). Previous techniques reported to evaluate final arytenoid position include post-operative laryngeal evaluation using endoscopy (Griffiths et al. 2001) or a handheld laryngoscope, either by the surgeon (White 1989) or intraoperative by a surgical assistant (Weinstein & Weisman 2010). However, if the surgeon is not satisfied with the degree of arytenoid abduction on post-operative laryngeal examination, the decision to perform a revision surgery may be difficult as the suture has already been secured. Replacing the suture may increase the risk of cartilage fracture with subsequent needle passes through the sometimes brittle cartilage of the muscular process. Furthermore, a second procedure increases anesthetic time, potentially increasing the chance of complications, as well as increasing the cost to the owner. Subsequently, it is the authors’ opinion that one may be inclined to accept a less than ideal position of the arytenoid to avoid revision laryngoplasty. This potential for acceptance of varying degrees of cricoarytenoid abduction may lead to inconsistent clinical outcomes. It is worth noting that the incidence of major complications including aspiration pneumonia (10%–24%) and recurrence (4%–20%) vary not only by surgical technique, but also within techniques (Rosin & Greenwood 1982; White 1989; Burbidge et al. 1993; MacPhail & Monnet 2001; Hammel et al. 2006; Schofield et al. 2007; Stanley et al. 2010; Monnet & Tobias 2012). Intra-technique variability in the percent increase in rima glottidis surface area may play a role in complications in the clinical setting (Bureau & Monnet 2002; Greenberg et al. 2007). The use of a 10-mm rigid endoscope for post-operative laryngeal evaluation has been performed with exceptional laryngeal imaging reported. (Dr Clarence Rawlings, personal communication). The authors feel that VAUCAL

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Veterinary Quarterly offers several advantages over previously described techniques, primarily the ability of the operating surgeon to have real-time evaluation and precise control of final arytenoid position at the time of knot tying. Furthermore, VAUCAL negates the necessity for the surgeon to scrub out or use an assistant for assessment of arytenoid abduction, potentially shortening total anesthetic and surgical time. It is worth noting that all dogs in the current study had a good-to-excellent short-term outcome, consistent with previous reports in dogs following surgical treatment for bilateral idiopathic laryngeal paralysis (White 1989; Burbidge et al. 1993; MacPhail & Monnet 2001; Hammel et al. 2006; Monnet & Tobias 2012). Although there is no direct support for a clinically superior outcome with VAUCAL, from a practical standpoint, this technique seems to offer advantages over standard intra-operative and post-operative methods to assess cricoarytenoid abduction; further studies may demonstrate these advantages. The main concerning complication observed in this study was loose cricoarytenoid suture placement in two dogs. Low-to-moderate tensioning of the suture resulted in adequate abduction of the arytenoid cartilage as viewed on the video monitor and a secure knot was tied; however, post-operative laryngoscopy revealed complete loss of arytenoid abduction. On re-exploration, an intact but loose cricoarytenoid suture was identified in both dogs. A plausable explanation for this is lack of attention to removing slack from the suture line prior to tensioning. This may have resulted from the surgeon’s focus being directed towards the video monitor during tensioning and securing of the cricoarytenoid suture. In both cases, the sutures were removed and replaced with another cricoarytenoid suture. Post-operative laryngoscopy following revision surgery revealed adequate abduction of the arytenoid cartilage in both dogs. Care must be taken to ensure that there is no residual slack in the suture line when tensioning the cricoarytenoid suture under video assistance. Several limitations must be acknowledged in this descriptive study. First, we aimed only to determine if VAUCAL was feasible in a small series of dogs with idiopathic bilateral laryngeal paralysis. As such, no conclusions can be made about any influence on clinical outcome. Further, due to the low number of cases, it may be that other complications or difficulties with this technique went undetected in our study. However, we were able to show that VAUCAL is feasible in a small group of dogs with bilateral idiopathic laryngeal paralysis. 5. Conclusion VAUCAL is an acceptable method for treating dogs with bilateral idiopathic laryngeal paralysis. VAUCAL permits direct visualization of the larynx during tensioning of the cricoarytenoid suture, as well as assessment of final arytenoid position intra-operatively by the operating surgeon. Other potential benefits of VAUCAL include excellent

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visualization of the larynx, precise control of the degree of abduction of the arytenoid cartilage, and possibly increased consistency in final arytenoid positioning. However, further studies are needed to test these assertions.

References Burbidge HM, Goulden BE, Jones BR. 1993. Laryngeal paralysis in dogs: an evaluation of the bilateral arytenoid lateralisation procedure. J Small Anim Pract. 34:515–519. Bureau S, Monnet E. 2002. Effects of suture tension and surgical approach during unilateral arytenoid lateralization on the rima glottidis in the canine larynx. Vet Surg. 31:589–595. Demetriou JL, Kirby BM. 2003. The effect of two modifications of unilateral arytenoid lateralization on rima glottidis area in dogs. Vet Surg. 32:62–68. Greenberg MJ, Bureau S, Monnet E. 2007. Effects of suture tension during unilateral cricoarytenoid lateralization on canine laryngeal resistance in vitro. Vet Surg. 36:526–532. Griffiths LG, Sullivan M, Reid SWJ. 2001. A comparison of the effects of unilateral thyroarytenoid lateralization versus cricoarytenoid laryngoplasty on the area of the rima glottidis and clinical outcome in dogs with laryngeal paralysis. Vet Surg. 30:359–365. Hammel SP, Hottinger HA, Novo RE. 2006. Postoperative results of unilateral arytenoid lateralization for treatment of idiopathic laryngeal paralysis in dogs: 39 cases (1996– 2002). J Am Vet Med Assoc. 228:1215–1220. Lozier S, Pope E. 1992. Effects of arytenoid abduction and modified castellated laryngofissure on the rima glottidis in canine cadavers. Vet Surg. 21:195–200. Lussier B, Flanders JA, Erb HN. 1996. The effect of unilateral arytenoid lateralization on rima glottidis area in canine cadaver larynges. Vet Surg. 25:121–126. MacPhail CM, Monnet E. 2001. Outcome of and postoperative complications in dogs undergoing surgical treatment of laryngeal paralysis: 140 cases (1985–1998). J Am Vet Med Assoc. 218:1949–1956. Monnet E, Tobias K. 2012. Larynx. In: Tobias K, Johnston S, editors. Veterinary surgery: small animal. St. Louis (MO): Elsevier Saunders; p. 1726–1728. Olivieri M, Voghera SG, Fossum TW. 2009. Video-assisted left partial arytenoidectomy by diode laser photoablation for treatment of canine laryngeal paralysis. Vet Surg. 38:439–444. Rosin E, Greenwood K. 1982. Bilateral arytenoid cartilage lateralization for laryngeal paralysis in the dog. J Am Vet Med Assoc. 180:515–518. Schofield DM, Norris J, Sadanaga KK. 2007. Bilateral thyroarytenoid cartilage lateralization and vocal fold excision with mucosoplasty for treatment of idiopathic laryngeal paralysis: 67 dogs (1998–2005). Vet Surg. 36:519–525. Stanley BJ, Hauptman JG, Fritz MC, Rosenstein DS, Kinns J. 2010. Esophageal dysfunction in dogs with idiopathic laryngeal paralysis: a controlled cohort study. Vet Surg. 39:139– 149. Weinstein J, Weisman D. 2010. Intraoperative evaluation of the larynx following unilateral arytenoid lateralization for acquired idiopathic laryngeal paralysis in dogs. J Am Anim Hosp Assoc. 46:241–248. White RAS. 1989. Unilateral arytenoid lateralisation: an assessment of technique and long term results in 62 dogs with laryngeal paralysis. J Small Anim Pract. 30:543–549. Wignall JR, Baines SJ. 2012. Effects of unilateral arytenoid lateralization technique and suture tension on airway pressure in the larynx of canine cadavers. Am J Vet Res. 73: 917–924.

Video-assisted unilateral cricoarytenoid laryngoplasty in 14 dogs with bilateral idiopathic laryngeal paralysis.

Unilateral cricoarytenoid laryngoplasty is commonly performed for treatment of idiopathic laryngeal paralysis in dogs. Determination of the appropriat...
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