Paranasal Sinus Lavage

Take Home Message—There is no single treatment regime that will ensure that an affected sinus is flushed of all abnormal material. Treatment must be pursued on a case-by-case approach. Irrespective of the method chosen, removal of inspissated material and resolution of infection is the ultimate goal.

I. Introduction

Sinus lavage is a routine adjunct therapy for the treatment of primary and dental (secondary) sinusitis. That said it is not necessary in all cases and the treatment regime for each horse must be tailored to meet the requirements of the horse as well as any limitations that the client may impose on the management situation.¹ The following paper describes the authors’ personal approach to sinus lavage in the horse.

II. Primary sinusitis

Typically if the case presentation suggests a primary sinusitis associated with an upper respiratory tract viral infection which has become secondarily infected and the nasal discharge (either uni- or bilateral) is of short duration, the author does not flush the sinuses. A short course of antibiotics may be necessary, but in some cases resolution occurs spontaneously. If the discharge does not spontaneously resolve, or if it responds to antibiotic therapy but recurs after cessation of the treatment, then further investigation is necessary.

III. Secondary sinusitis

All horses with chronic unilateral nasal discharge (especially those with a fetid odor) undergo a complete oral examination and radiographs of the sinuses. Standard projections at our institution include a laterolateral, two oblique laterals, a dorsoventral and an offset dorsoventral. If no significant abnormalities (such as periapical disease, sinus cysts or ethmoidal hematomas) are detected then a small sinusotomy is performed using a Jacob’s chuck and 4mm Steinmann pin. Depending on the management situation an indwelling catheter (Foley) will be placed and secured using a Chinese Fingertrap suture, or a dog urinary catheter will be used to flush the sinus (being placed by the owner when necessary). The 4mm hole is sufficient to place an arthroscope and in most instances sinoscopy of the sinus will be performed at the same time (to look for evidence of inspissated pus or an obvious cause of the chronic discharge.^2,3

If there are significant intra-sinus abnormalities detected on radiography (or if there is sufficient justification to suspect this) then computed tomography is typically discussed with the client. This author usually does not consider sinus lavage until the underlying pathology is addressed in most cases. The single instance where sinus lavage may be performed prior to further treatment is in cases where computed tomography is declined, but the opacities within the sinus are obscured with purulent material. In these cases, the sinus will be lavaged in an attempt to clear it of debris before repeat radiographs are taken.

Sinus lavage is performed using room-temperature lactated Ringer’s solution or normal (0.9%) saline. Initially the fluid is administered using gravity-feed and at this stage the amount of fluid exiting the sinus is assessed. If there is minimal to no drainage, despite filling the sinus then adjunct treatment may be necessary. There is little point in accepting sub-optimal sinus lavage if this is the main-stay (or even a major adjunct) of your treatment plan. If the non-viscus saline cannot exit the sinus, the thick mucopurulent debris is not going to. In these cases, endoscopic-guided balloon sinuplasty may be performed (antegrade as published, or in retrograde fashion).⁴ Once the nasomaxillary opening is widened, the author commonly attaches a fluid pump to the ingress tubing. This allows for fluid to be passed at high rate into the affected sinus to attempt to dislodge tenacious debris and to break up friable inspissated pus that, without manipulation, is too large to exit the sinus.

Some clinicians advocate ablation or destruction of the medial wall of the ventral conchal sinus as a method of establishing good drainage from this sinus cavity. The author very rarely uses this method for several reasons; firstly drainage established using balloon sinuplasty has been successful in managing cases thus far. Secondly (and this could be considered “old-school”) sinusotomies using bone flap techniques are performed under general anesthesia in our institution. One major reason (among others) cited for standing surgery is the fact that the elevated position of the head results in less blood loss. The major cause of blood loss is the ventral conchal sinusotomy through the highly vascular nasal mucosa and associated vascular plexus. If the surgeon does not need to perform the sinusotomy then there is little blood loss and thus one less argument for standing surgery.

In the authors’ opinion, management of sinus condition using minimally invasive approaches is preferable to performing a large osteotomy.³ However, in cases of chronic sinusitis where significant mucosal proliferation has occurred, a flap osteotomy may be unavoidable in order to remove as much of the hyperplastic tissue as possible. This highly vascular surgery may be necessary to improve drainage but also to decrease the infectious load within this closed system. These surgeries tend to hemorrhage to the point that adequate visualization is compromised. In these cases, the author packs the sinus using a bandage which is passed via the iatrogenically expanded nasomaxillary opening out of the nose. This is removed standing on the second day after surgery. Other clinicians have reported on repeated visual re-evaluation following surgery which as yet this author has not done.⁵

IV. Summary

Sinus disease is fraught with complications. Clients should be made aware that several visits and treatments are likely. Despite this the majority of sinus conditions (either primary or secondary) will respond to therapy in the long-term.^6,7

References

1. Dixon PM, O'Leary JM. A review of equine paranasal sinusitis: Medical and surgical treatments. Equine Veterinary Education 2012;24:143-158.
2. Perkins JD, Bennett C, Windley Z, et al. Comparison of Sinoscopic Techniques for xamining the Rostral Maxillary and Ventral Conchal Sinuses of Horses. Veterinary Surgery 2009;38:607-612.
3. Perkins JD, Windley Z, Dixon PM, et al. Sinoscopic Treatment of Rostral Maxillary and Ventral Conchal Sinusitis in 60 Horses. Veterinary Surgery 2009;38:613-619.
4. Bell C, Tatarniuk D, Carmalt J. Endoscope-Guided Balloon Sinuplasty of the Equine Nasomaxillary Opening. Veterinary Surgery 2009;38:791-797.
5. Hart SK, Sullins KE. Evaluation of a novel post operative treatment for sinonasal disease in the horse (1996-2007). Equine Veterinary Journal 2011;43:24- 29.
6. Stoian C, Simhofer H, Zetner K. Secondary sinusitis caused by dental problems in 22 horses: diagnosis, treatment and long-term results. Praktische Tierarzt 2006;87:26-30.
7. Dixon PM, Parkin TD, Collins N, et al. Equine paranasal sinus disease: A long-term study of 200 cases (1997-2009): Treatments and long-term results of treatments. Equine Veterinary Journal 2012;44:272- 276.