Indications for and short- and long-term outcome of permanent tracheostomy performed in standing horses: 82 cases (1995–2005)

A. Berkley Chesen Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4475.

Search for other papers by A. Berkley Chesen in
Current site
Google Scholar
PubMed
Close
 DVM
and
Peter C. Rakestraw Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4475.

Search for other papers by Peter C. Rakestraw in
Current site
Google Scholar
PubMed
Close
 VMD, DACVS

Abstract

Objective—To identify indications for and short- and long-term outcome of permanent tracheostomy performed in standing horses.

Design—Retrospective case series.

Animals—82 horses undergoing permanent tracheostomy.

Procedures—Data obtained from medical records included signalment, diagnosis, surgical technique, complications, use of the horse before and after surgery, and owner satisfaction. Follow-up information was obtained through a telephone questionnaire administered to owners.

Results—Indications for permanent tracheostomy included nasopharyngeal cicatrix (n = 59), arytenoid chondropathy (55), and laryngeal hemiplegia (20); 54 horses had multiple indications for tracheostomy. Complications identified prior to discharge included partial dehiscence (n = 8), transient fever (10), and excessive swelling (13). Complications identified after discharge included partial dehiscence (n = 3), inversion of skin (2), and stenosis of the tracheostomy requiring repair (1). Long-term follow-up information was available for 64 horses. Fifty-seven of the 64 (89%) horses returned to their previous use, and owners of 63 (98%) horses reported being very satisfied with the results. The owner of 1 (2%) horse was unsatisfied with the results. The 1-year survival rate was 97% (95% confidence interval, 95% to 100%). Mean estimated truncated survival time (ie, failure-free period) was 9.7 years (95% confidence interval, 9.3 to 10.1 years).

Conclusions and Clinical Relevance—Results suggested that permanent tracheostomy can be safely performed in standing horses and was a viable treatment for horses with obstructive disease of the upper respiratory tract that was unresponsive to medical treatment or other surgical treatments.

Abstract

Objective—To identify indications for and short- and long-term outcome of permanent tracheostomy performed in standing horses.

Design—Retrospective case series.

Animals—82 horses undergoing permanent tracheostomy.

Procedures—Data obtained from medical records included signalment, diagnosis, surgical technique, complications, use of the horse before and after surgery, and owner satisfaction. Follow-up information was obtained through a telephone questionnaire administered to owners.

Results—Indications for permanent tracheostomy included nasopharyngeal cicatrix (n = 59), arytenoid chondropathy (55), and laryngeal hemiplegia (20); 54 horses had multiple indications for tracheostomy. Complications identified prior to discharge included partial dehiscence (n = 8), transient fever (10), and excessive swelling (13). Complications identified after discharge included partial dehiscence (n = 3), inversion of skin (2), and stenosis of the tracheostomy requiring repair (1). Long-term follow-up information was available for 64 horses. Fifty-seven of the 64 (89%) horses returned to their previous use, and owners of 63 (98%) horses reported being very satisfied with the results. The owner of 1 (2%) horse was unsatisfied with the results. The 1-year survival rate was 97% (95% confidence interval, 95% to 100%). Mean estimated truncated survival time (ie, failure-free period) was 9.7 years (95% confidence interval, 9.3 to 10.1 years).

Conclusions and Clinical Relevance—Results suggested that permanent tracheostomy can be safely performed in standing horses and was a viable treatment for horses with obstructive disease of the upper respiratory tract that was unresponsive to medical treatment or other surgical treatments.

Permanent tracheostomy has previously been recommended for the treatment of horses with severe obstruction of the upper respiratory tract that is not amenable to medical or other surgical treatments.1–4 Short-term complications that have been reported include incisional swelling, infection, and dehiscence, and long-term complications include a predisposition to lower respiratory tract disease, stenosis of the stoma, and tracheal collapse.5 However, the incidence of complications following permanent tracheostomy in horses is not known. In addition, little information is available on short- and long-term care required for horses that have undergone permanent tracheostomy or on the likelihood that horses that have undergone this procedure will be able to return to their previous use.

Methods for performing a permanent tracheostomy in anesthetized horses have been described.2,3 However, because of the risks associated with anesthetizing horses with respiratory tract disease and because positioning horses in dorsal recumbency may distort the anatomic relationships of the structures of the neck, methods for performing permanent tracheostomy in standing horses have also been described.1 The purpose of the study reported here was to identify indications for and short- and long-term outcome of permanent tracheostomy performed in standing horses.

Materials and Methods

Case selection criteria—Medical records of horses examined at the Texas A&M University Veterinary Medical Center between April 1995 and October 2005 were searched to identify horses that underwent permanent tracheostomy. Horses were eligible for inclusion in the study only if the procedure had been performed while the horse was standing.

Medical records review—Information obtained from the medical records of horses included in the study consisted of signalment, indications for permanent tracheostomy (ie, disease conditions necessitating permanent tracheostomy), whether a temporary or permanent tracheostomy had previously been performed, surgical technique (ie, number and location of tracheal rings excised), hospitalization time, and complications identified prior to discharge. In all horses, videoendoscopya of the respiratory tract had been performed prior to surgery to confirm the diagnosis of upper respiratory tract obstruction.

Tracheostomy technique—In horses in severe respiratory distress, a temporary tracheostomy was performed as described.6 The stoma for the temporary tracheostomy was positioned in the middle portion of the ventral aspect of the neck so as to avoid interfering with the site for the subsequent permanent tracheostomy.

For the permanent tracheostomy, the horse was placed in stocks and sedated with detomidine (0.02 mg/kg [0.009 mg/lb], half of the dose given IV and the other half given IM) and butorphanol tartrate (0.02 mg/kg, half of the dose given IV and the other half given IM). After the horse appeared sedate, a dental halter consisting of a metal ring covered with leather to which 4 small rings had been attached equidistant around the circumference of the metal ring was placed over the horse's head (Figure 1). The throat latch strap of the halter was removed and placed across the dorsal part of the halter so it would not interfere with the surgical site. A support rope was attached to the most dorsal of the 4 small rings on the halter and tied to an overhead bar extending forward from the stocks. Two lateral support ropes were also attached to the halter; these ropes were draped over the top sides of the stocks and tied to the side bars.

Figure 1—
Figure 1—

Positioning of the head and neck when performing permanent tracheostomy in a standing horse.

Citation: Journal of the American Veterinary Medical Association 232, 9; 10.2460/javma.232.9.1352

Permanent tracheostomy was performed as described,1 with minor modifications. In brief, local anesthetic was infiltrated in an inverted U pattern surrounding the region of the second through sixth tracheal rings. A 4 × 7-cm rectangular or elliptical incision was made centered on the midline, and skin and subcutaneous tissues were removed. Ferguson angiotrib forcepsb were used to crush the portions of the sternohyoideus, sternothyroideus, and omohyoideus muscles at the proximal and distal aspects of the incision. The forceps were then removed, and the muscles were resected by means of electrocoagulation.c A 23-gauge, 2.5-cm-long needle was inserted through the tracheal mucosa, and 20 to 30 mL of 2% lidocaine hydrochloride was infused into the tracheal lumen to desensitize the tracheal mucosa. The desired tracheal rings were then incised on the midline, and the rings were undermined in both directions abaxially so that approximately a third of each tracheal ring could be removed. Care was taken to not penetrate the tracheal mucosa at this stage. After the desired segments of rings had been removed, a double Y incision was made through the tracheal mucosa, and the tracheal mucosa was sutured to the skin with size 0 polyglactin 910 in a simple interrupted pattern.

Procaine penicillin (22,000 U/kg [10,000 U/lb], IM, q 12 h) was administered for 3 to 5 days after surgery, and flunixin meglumine (1.1 mg/kg [0.5 mg/lb], IV, q 12 h) was administered for 7 days after surgery. Drains that were placed at the time of surgery were removed after 3 days. At the time of hospital discharge, owners were instructed to keep horses in an area where they would not be able to rub the surgical site (ie, away from fences, half-doors, and trees) until after the site was well-healed and to clean the site with warm compresses daily for 30 to 60 days or until excessive discharge was no longer a problem. Owners were also instructed to keep horses away from deep water and to use caution when bathing the horses to keep water from entering the stoma.

Follow-up protocol—Follow-up information was obtained through a telephone questionnaire administered to owners. Owners were asked to provide information on the current status of their horse, if the horse was still alive and in their possession, or on the status of their horse at the time of sale or death. Information obtained from owners included whether they still owned the horse and, if not, whether the horse's death or sale was related to respiratory tract problems; whether the horse had a persistent cough or nasal discharge, made any respiratory noise, or had had any episodes of respiratory distress; how often the stoma had to be cleaned and how long after surgery it was before the stoma did not require daily cleaning; whether there had been any problem with the function of the stoma and, if so, whether the stoma had been surgically corrected since the original surgery; how long the stoma remained patent; horse use before and after surgery; and degree of satisfaction with the procedure and whether the owner would have the procedure done in another horse under similar circumstances.

Statistical analysis—Because duration of follow-up varied among horses, Kaplan-Meier estimator methods for time-to-event data were used to analyze distributions of times to failure of permanent tracheostomy. Failure was defined as euthanasia of the horse because of problems with the tracheostomy or any event that resulted in a need for revision of the permanent tracheostomy. Horses were censored if they had not had a failure of the permanent tracheostomy at the time of final follow-up or had died of causes unrelated to the permanent tracheostomy or the condition for which the procedure had been indicated. Survival data were summarized by means of Kaplan-Meier plots, and the truncated estimated mean survival time was calculated. All analyses were performed with standard software.d

Results

Eighty-one horses and 1 donkey fulfilled the criteria for inclusion in the study. There were 60 mares, 1 jenny, 18 geldings, and 3 sexually intact males. Mean age was 16.3 years (range, 2 to 28 years). There were 54 Quarter Horses, 9 Arabians, 4 American Paints, 6 Thoroughbreds, 1 Appaloosa, 1 Warmblood, 1 Miniature Horse, 5 mixed-breed horses, and 1 Mammoth Donkey.

Abnormalities identified during videoendoscopy of the upper respiratory tract included nasopharyngeal cicatrix (n = 59 [72%]), arytenoid chondropathy (55 [67%]), and laryngeal hemiplegia (20 [24%]). Fifty-four (66%) of the horses had multiple abnormalities necessitating permanent tracheostomy.

In 35 (43%) horses, temporary tracheostomy was performed prior to permanent tracheostomy. Three horses required a temporary tracheostomy at the time of surgery because of respiratory distress, and 2 horses had undergone permanent tracheostomy previously, including 1 horse that had undergone the procedure twice previously.

In 77 (94%) horses, the permanent tracheostomy was positioned in the proximal third of the ventral aspect of the neck, and in 5 (6%), the permanent tracheostomy was positioned in the middle third of the ventral aspect of the neck. In 26 (32%) of the horses, the ventral third of 4 tracheal rings was removed; in 42 (51%), the ventral third of 5 tracheal rings was removed; and in 6 (7%), the ventral third of 6 tracheal rings was removed. In the remaining 8 (10%) horses, the number of tracheal rings removed was not recorded.

Complications identified prior to hospital discharge included partial dehiscence of the area where the skin was sutured to mucosa (n = 8 [10%]), transient fever (rectal temperature > 38.9°C [102°F]; 10 [12%]), and excessive swelling (13 [16%]). In 2 of the horses with dehiscence, the area was resutured. Two of the horses with excessive swelling had a hematoma. Median hospitalization time was 6 days (range, 1 to 40 days).

Follow-up information was obtained from owners of 64 of the 82 (78%) horses. Time from surgery to final follow-up ranged from 1 month to 10 years (mean, 3.2 years). Complications identified following discharge in the 64 horses available for follow-up included partial dehiscence of the skin-mucosa suture (n = 3 [5%]), inversion of the skin edges (2 [3%]), and stenosis of the tracheostomy requiring enlargement (1 [2%]). Mean time until daily cleaning of the stoma was no longer necessary was 2 months (range, < 1 to 6 months). Frequency of cleaning after this time ranged from once a week to once every several months, although most owners reported that they cleaned the stoma monthly.

Forty-five of the 64 (70%) horses available for follow-up were still alive and in the possession of the person who had owned the horse at the time of surgery, and 19 (30%) had been sold or were dead. Two of the 64 (3%) horses died or were euthanatized because of respiratory tract complications (1 month and 9 months after surgery). Nine (14%) horses were culled from broodmare herds 1 to 9 years (mean, 2.2 years) after surgery. These 9 horses had not had any history of respiratory tract complications following discharge and were reportedly culled as part of the herds' routine management of aged broodmares. Five (8%) horses died of gastrointestinal tract disease between 3 and 7 years (mean, 5.4 years) after surgery. One (1.6%) horse was euthanatized because of clostridial myositis 2 years after surgery, 1 (1.6%) horse was euthanatized because of severe arthritis 2 years after surgery, and 1 (1.6%) horse was given to a child as a riding horse 5 years after surgery.

Eleven of the 64 (17%) horses available for follow-up had a low-grade chronic cough, 1 (1.6%) had chronic nasal discharge, 7 (11%) had evidence of respiratory tract noise when physically active, and 4 (6%) had intermittent episodes of respiratory distress. Three of the horses with respiratory tract noise also had episodes of respiratory distress, and 1 of the horses with respiratory tract noise also had a low-grade chronic cough.

Fifty-seven of the 64 (89%) horses available for follow-up returned to their previous use, including 30 that returned to use as broodmares, 5 that returned to Western performance activities, 15 used for pleasure riding, 6 that had been retired prior to surgery, and 1 used as a breeding stallion. Two of the 7 horses that did not return to their previous use were retired from competitive activities and used as pleasure riding horses, 4 were retired from being ridden, and 1 went from being a riding horse to being a broodmare.

Sixty-three of the 64 (98%) owners reported that they were very satisfied with the outcome of the procedure; 1 (1.6%) was not satisfied. Sixty-three of the 64 (98%) owners indicated that they would recommend the procedure in a similar situation.

Survival rate after 1 year was 97% (95% confidence interval, 95% to 100%). Estimated truncated survival time (ie, failure-free period) was 9.7 years (95% confidence interval, 9.3 to 10.1 years; Figure 2).

Figure 2—
Figure 2—

Kaplan-Meier curve of time to failure following permanent tracheostomy in 64 horses. Small vertical marks on the horizontal portion of the curve represent censored values. Dotted lines represent the 95% confidence interval for the estimated proportion without failure.

Citation: Journal of the American Veterinary Medical Association 232, 9; 10.2460/javma.232.9.1352

Discussion

Results of the present study suggested that permanent tracheostomy could be safely performed in standing horses and was a viable treatment for horses with obstructive disease of the upper respiratory tract that was unresponsive to medical treatment or other surgical treatments. The most common indication for permanent tracheostomy among horses in this study was nasopharyngeal cicatrix. This is the most common disorder of the upper respiratory tract among horses examined at the Texas A&M University Veterinary Medical Center,4,7 and it has been the experience of veterinarians at the Veterinary Medical Center that this condition does not respond well to other forms of treatment, surgical or medical, and that permanent tracheostomy is the best treatment option.8 Arytenoid cartilage thickening has been reported to occur in 78% of horses with nasopharyngeal cicatrix,8 and treatment of complicated arytenoid chondritis by means of partial arytenoidectomy often yields poor results.4 It is the authors' opinion that the chronic inflammation associated with nasopharyngeal cicatrix and the subsequent arytenoid chondritis result in poor tissue healing after partial arytenoidectomy, with formation of excessive scar tissue. Laser resection of the cicatrix has only been palliative, as the cicatrix often reforms unless the horse is moved to a different environment. However, the authors do not recommend permanent tracheostomy as the first-line treatment for conditions, such as laryngeal hemiplegia and uncomplicated arytenoid chondritis, for which other treatments are available.

In 35 of the horses in the present study, temporary tracheostomy was performed prior to permanent tracheostomy because of severe respiratory distress. This included 3 horses in which temporary tracheostomy was performed at the time of surgery for permanent tracheostomy. In these horses, it seems likely that respiratory distress was exacerbated by sedation and the extended position of the head and neck. Because of the high incidence of nasopharyngeal cicatrix in our area, we recommend that referring veterinarians who perform a temporary tracheostomy place the stoma in the middle third of the ventral aspect of the neck in case permanent tracheostomy is subsequently required.

Although tracheal collapse has been reported to be a potential complication of permanent tracheostomy,1 none of the horses in the present study reportedly developed tracheal collapse following surgery. It has been the experience of one of the authors (PCR) that not removing a sufficient portion of the ventral aspect of the tracheal rings results in inversion of the stoma and that this is a more common problem than tracheal collapse secondary to removing too large a portion of the tracheal rings. We have also observed that removing a portion of the omohyoideus muscle, in addition to removing portions of the sternohyoideus and sternothyroideus muscles, appears to decrease inversion of the stoma.

Permanent tracheostomy is typically performed in the proximal third of the ventral aspect of the neck. This position provides protection from the elements and a better cosmetic outcome. In 5 horses in the present study, however, the stoma had to be placed in the middle third of the ventral aspect of the neck because of a previous permanent tracheostomy or temporary tracheostomy in the proximal third of the neck. The ventral aspects of 4 to 6 tracheal rings were removed, resulting in a stomal length that was adequate for airflow even in athletic horses after healing and contraction but that also provided acceptable cosmetic results by not changing the contour of the neck (Figure 3). Typically, the ventral aspects of the second through sixth tracheal rings were removed. Removal of the first tracheal ring in humans has reportedly caused subepiglottic stenosis.9

Figure 3—
Figure 3—

Lateral (A) and ventral (B) views of a permanent tracheostomy in a horse 6 months after surgery.

Citation: Journal of the American Veterinary Medical Association 232, 9; 10.2460/javma.232.9.1352

A potential complication of permanent tracheostomy in broodmares that has been discussed is an inability to close the glottis for an abdominal press during labor.1 Although we continue to inform owners of this potential complication, none of the 31 broodmares in the present study reportedly had any complications with foaling after tracheostomy was performed, and these 31 mares produced more than 50 foals without complications at parturition. The most common comment from owners regarding parturition was that the mares could not nicker normally to their foals.

Seven horses in the present study did not return to their previous use after undergoing permanent tracheostomy. However, owners of all 7 of these horses reported that this was not a result of respiratory tract problems. Owners of 19 horses indicated that they no longer were in possession of the horse when contacted for follow-up information. Two of these horses reportedly died of respiratory tract problems.

Eleven horses had a mild, chronic, intermittent cough that, according to the owners, was worse when it was dusty and at the beginning of exercise. This cough was most likely due to irritation of the tracheal mucosa. One owner reported that when conditions were excessively dusty, her horse could not compete in barrel racing because of excessive coughing.

Pneumonia has been reported as a potential complication of permanent tracheostomy secondary to decreased filtration and humidification of inspired air. Although 2 horses in the present study had a history of pneumonia, neither developed pneumonia after surgery, and in 1, the pneumonia resolved after surgery and appropriate antimicrobial treatment.

Seven horses were reported to have abnormal respiratory tract noises after surgery. A potential cause may have been air movement through the nasal passages, nasopharynx, and larynx creating turbulent airflow. Four horses reportedly had episodes of moderate respiratory distress characterized by increased respiratory rate and effort. Three of these 4 horses were also reported to have abnormal respiratory tract noise, and in these horses, the noise and respiratory distress were likely a result of inadequate size or inversion of the tracheal stoma during increased respiratory effort. In a previous report10 of permanent tracheostomy in dogs and cats, skinfold occlusion of the stoma was the most common complication.

One disadvantage of permanent tracheostomy is the maintenance involved in cleaning the stoma, and owners of horses in the present study reported that they had to clean the site daily for 1 to 6 months after surgery. Anecdotally, we have noticed that if sutures are removed 2 weeks after surgery, the amount of discharge from the site decreases dramatically over the next 2 weeks, whereas if sutures are allowed to dissolve, discharge remained copious for up to 2 months. Most owners reported cleaning the site only intermittently after daily cleaning was no longer needed.

For horses in the present study, the 1-year survival rate was 97% and no failures were reported after 1 year among horses that were followed up longer than this. Additional long-term follow-up is needed to better define the mean failure-free period, but estimated mean failure-free period in the present study was 9.7 years. Methods used to estimate the mean failure-free period are recognized to be conservative (ie, the truncation method results in a bias toward lower numbers).

In conclusion, results of the present study suggested that permanent tracheostomy performed in a standing position should be considered for horses with upper airway obstruction when other surgeries or treatments are unlikely to resolve the condition. Short-term complications were not uncommon, but long-term complications were minimal, with the most common long-term complications being mild cough at the beginning of exercise and abnormal respiratory tract noise. Long-term complications were generally considered minor by the owners and did not affect the use of the animal, and most owners were satisfied with the outcome. Importantly, although none of the horses in the present study were racehorses, it is illegal in the United States to race a horse with a permanent tracheostomy.

a.

Olympus America Inc, Tokyo, Japan.

b.

Miltex, Lake Success, NY.

c.

Ligasure, Valleylab, Boulder, Colo.

d.

S-PLUS, version 7.0, Insightful Inc, Seattle, Wash.

References

  • 1.

    McClure SR, Taylor TS, Honnas CM, et al. Permanent tracheostomy in standing horses: technique and results. Vet Surg 1995;24:231234.

  • 2.

    Shappell KK, Stick JA, Derksen FJ, et al. Permanent tracheostomy in Equidae: 47 cases (1981–1986). J Am Vet Med Assoc 1988;192:939942.

    • Search Google Scholar
    • Export Citation
  • 3.

    Honnas CM. Diseases of the trachea. In: Colahan PT, Mayhew IG, Merrit AM, et al, eds. Equine medicine and surgery. Vol 1. Goleta, Calif: American Veterinary Publications, 1991;424429.

    • Search Google Scholar
    • Export Citation
  • 4.

    Dean PW, Cohen ND. Arytenoidectomy for advanced unilateral chondropathy with accompanying lesions. Vet Surg 1990;19:364370.

  • 5.

    Hedlund CS, Tangner CH, Montgomery DL, et al. A procedure for permanent tracheostomy and its effects on tracheal mucosa. Vet Surg 1982;11:1317.

    • Search Google Scholar
    • Export Citation
  • 6.

    Auer JA, Stick JA. Trachea. In: Equine surgery. 3rd ed. St Louis: Elsevier Saunders, 2006;610611.

  • 7.

    Schumacher J, Hanselka DV. Nasopharyngeal cicatrices in horses: 47 cases (1972–1985). J Am Vet Med Assoc 1987;191:239242.

  • 8.

    Rakestraw PC. Equine nasopharyngeal cicatrix syndrome, in Proceedings. Texas A&M Univ Annu Equine Conf 2003;4043.

  • 9.

    Grillo HC. Surgery of the trachea. Curr Probl Surg 1970;7:357.

  • 10.

    Hedlund CS, Tangner CH, Waldron DR, et al. Permanent tracheostomy: perioperative and long-term data from 34 cases. J Am Anim Hosp Assoc 1988;24:585591.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 308 0 0
Full Text Views 2024 1210 43
PDF Downloads 1367 672 37
Advertisement