Clinical features and management of equine post operative ileus (POI): Survey of Diplomates of the American Colleges of Veterinary Internal Medicine (ACVIM), Veterinary Surgeons (ACVS) and Veterinary Emergency and Critical Care (ACVECC).

REASONS FOR PERFORMING STUDY: A recent survey of European Colleges (European College of Equine Internal Medicine [ECEIM] and European College of Veterinary Surgeons [ECVS]) revealed the different strategies implemented by, and some of the challenges facing, European clinicians presented with cases of post operative ileus (POI). It was concluded that further comparative analysis of opinions, canvassed from additional colleges of equine veterinary specialism worldwide, would provide valuable additional insight into current POI knowledge on a more global scale. OBJECTIVES: To report and compare the current strategies favoured by American veterinary specialists when managing POI in horses that underwent emergency colic surgery. STUDY DESIGN: Cross-sectional survey. METHODS: Electronic invitations were sent to 814 Large Animal specialists, including 3 colleges: the American College of Veterinary Internal Medicine (ACVIM), American College of Veterinary Surgeons (ACVS) and the American College of Veterinary Emergency and Critical Care (ACVECC). RESULTS: The response rate was 14% (115/814). The majority of respondents (68%) reported an estimated prevalence range of POI of 0-20%. The presence of reflux on nasogastric intubation was the main criterion used to define POI. A lesion involving the small intestine was considered the main risk factor for POI. Anti-inflammatory drugs, intravenous (i.v.) fluids and antimicrobial drugs were the primary strategies used when managing POI. Flunixin meglumine and i.v. lidocaine were the drugs most commonly used in the treatment of horses with POI. Supplementary management strategies targeted mainly the prevention of post operative adhesions, infection and inflammation. CONCLUSIONS: There is a lack of consensus on the clinical definition of POI. Prospective and objective clinical assessment of the effectiveness of the different strategies contained within this and the European survey is necessary in order to identify a standardised approach to the management of equine POI.

A database survey of equine tumours in the United Kingdom.

REASONS FOR PERFORMING STUDY: Survey data on equine tumours are sparse compared with other species and may have changed over time. OBJECTIVES: To describe the most frequently diagnosed equine tumours recorded by a diagnostic pathology laboratory over 29 years, to identify background factors associated with tumour type, and to identify any changes in the tumours diagnosed or the background of cases submitted during the study period. STUDY DESIGN: Observational; cross-sectional analysis of records of a diagnostic pathology laboratory. METHODS: The records of all neoplastic equine histology submissions to the University of Bristol (January 1982-December 2010) were accessed from a database, and a list of diagnoses compiled. The 6 most commonly diagnosed tumour types were analysed using logistic regression to identify background factors associated with tumour type. The overall population of equine tumour submissions and the relative frequency of diagnosis of the most common tumour types were compared between decades. RESULTS: There were 964 cases included. The most frequently diagnosed tumours were: sarcoid (24% cases), squamous cell carcinoma (SCC) (19%), lymphoma (14%), melanoma (6%), gonadal stromal tumour (6%) and mast cell tumour (MCT) (4%). With sarcoid, Thoroughbred/Thoroughbred cross and gelding as reference categories: increasing age was significantly associated with the odds of each of the other tumour types, mares were at reduced risk of SCC, Arab/Arab cross had a higher risk of MCT, Cob/Cob cross had an increased risk of SCC and MCT, and ponies had an increased risk of melanoma. The mean age of submissions increased in each successive decade and the breed composition became broader. Sarcoids and lymphoma formed a smaller proportion of diagnoses in later decades. CONCLUSIONS: The types of tumours submitted to this laboratory have changed over the last 3 decades. Current data inform clinicians and researchers and further studies are warranted to follow trends.

Caudal anaesthesia of the infraorbital nerve for diagnosis of idiopathic headshaking and caudal compression of the infraorbital nerve for its treatment, in 58 horses.

REASONS FOR PERFORMING STUDY: Idiopathic headshaking is often a facial pain syndrome, but a diagnostic protocol has not been described. In a previous study, caudal compression of the infraorbital nerve for treatment offered a fair success rate, but low case numbers and short follow-up time were limitations. OBJECTIVES: To describe a diagnostic protocol for headshaking, examining the role of bilateral local analgesia of the posterior ethmoidal nerve (PET block). To report longer-term follow-up after surgery of the original cases and further cases and to determine whether changes to the technique influence success rates and complications. METHODS: Records of horses that had undergone PET block and caudal compression surgery at 3 hospitals were reviewed. Modifications to the surgical technique included placing additional coils into the infraorbital canal and/or performing concurrent laser cautery of the nerve. Follow-up information was obtained by telephone contact with owners. RESULTS: The PET block was performed in 27 horses, with a positive result in 23 of 27 (85%). Surgery was performed in 58 horses. A successful outcome was initially achieved in 35 of 57 (63%) horses, but recurrence occurred between 9 and 30 months later in 9 (26%). Surgery was repeated in 10 of 31 (32%) horses. Final success rate, considering only response to the last performed surgery, was 28 of 57 (49%) horses with median follow-up time of 18 months (range 2-66 months). Nose-rubbing was reported post operatively in 30 of 48 (63%) horses. This resolved in all but 4 horses, which were subjected to euthanasia. Response to PET block or change in surgical technique did not appear to influence outcome or complications. CONCLUSIONS AND POTENTIAL RELEVANCE: The diagnostic protocol described is recommended for the investigation of headshakers. Caudal compression offers the best prognosis for a successful outcome compared with other treatments, for horses in which the only alternative is euthanasia. Surgical treatment of the disorder requires refinement, and the pathogenesis of the disorder requires investigation.

Equine paranasal sinus disease: a long-term study of 200 cases (1997-2009): ancillary diagnostic findings and involvement of the various sinus compartments.

REASONS FOR PERFORMING STUDY: There is a lack of objective information on the value of ancillary diagnostic techniques used to investigate equine sinus disease, and also on which sinus compartments are commonly affected in this disorder. OBJECTIVES: To record the ancillary diagnostic findings used to investigate equine sinus disease and to document which compartments are affected. MATERIALS AND METHODS: The clinical case records of 200 consecutive cases of sinus disease, including subacute (<2 months' duration) primary (n = 52); chronic (>2 months' duration) primary (n = 37); dental (n = 40); traumatic (n = 13); sinus cyst (n = 26); sinus neoplasia (n = 10); dental related oromaxillary fistula (n = 8); mycotic sinusitis (n = 7) and intra-sinus progressive ethmoid haematoma (n = 7) were retrospectively examined. RESULTS: Nasal endoscopy showed exudate draining from the sino-nasal ostia in 88% of cases and a sino-nasal fistula was present in 15% of cases. Sinoscopy was performed in 79% of cases and was of great diagnostic value. More recently, 22% of cases had fenestration of the ventral conchal bulla performed to allow sinoscopy of the rostral sinus compartments. Radiography was performed in 97% of cases and showed intra-sinus fluid lines to be common (69% prevalence) in subacute primary sinusitis. Radiographic dental apical changes were not specific to dental sinusitis, e.g. 29% of chronic primary sinusitis cases had radiographic dental changes. Scintigraphy was performed in 20% of cases and was helpful in identifying dental apical changes when radiography was inconclusive. Overall, the caudal maxillary (78% involvement) and rostral maxillary (61%) sinuses were most commonly affected, with the ventral conchal sinus (VCS) (54% involvement) and conchofrontal sinuses (48%) less so. The VCS showed the greatest tendency to contain inspissated pus (present in 46% of all affected VCS). CONCLUSIONS: Nasal endoscopy, sinoscopy and skull radiography are of great value in diagnosing the presence and causes of equine sinus disease.

Equine paranasal sinus disease: a long-term study of 200 cases (1997-2009): treatments and long-term results of treatments.

REASONS FOR PERFORMING STUDY: There is limited objective information available on the treatment and the long-term response to treatment of the different types of equine sinus disease. OBJECTIVES: To document the treatments and long-term response to these treatments in 200 cases of equine sinus disease (1997-2009). METHODS: The treatments of horses affected with subacute primary sinusitis (n = 52); chronic primary sinusitis (n = 37); dental sinusitis (n = 40); sinus cyst (n = 26); traumatic (n = 13); dental-related oromaxillary fistula (n = 8); sinus neoplasia (n = 10); mycotic sinus disease (n = 7); and intrasinus progressive ethmoid haematoma (n = 7) and the long-term response to these treatments were retrospectively reviewed. RESULTS: Treatments evolved throughout the study and latterly were as conservative as possible, including sinoscopic lavage and standing sinusotomy, with a maxillary sinusotomy approach preferred for the mainly mature horses treated in this study. Removal of intrasinus inspissated pus, including transendoscopically (by sinusotomy and via existing sinonasal fistulae), was the main treatment for chronic primary sinusitis and sinonasal fistulation was seldom performed latterly. Attempted oral extraction of infected cheek teeth, even if unsuccessful, facilitated subsequent dental repulsion, resulting in few post operative problems. Sinus cyst removal carried an excellent prognosis. Except for cases of sinus neoplasia (only 22% cured), an excellent long-term response to treatment (91% fully cured, 7% partially cured) was obtained for all other types of sinus disease following a median of one treatment. CONCLUSIONS: More conservative treatments, including removal of intrasinus inspissated pus by sinoscopy, pre-existing sinonasal fistula or sinusotomy, are effective for chronic primary sinus disease. Standing sinusotomy, mainly using a small maxillary site, was suitable for most cases of sinus disease in mature horses.

Supernumerary cheek teeth (n = 24): clinical features, diagnosis, treatment and outcome in 15 horses.

REASONS FOR PERFORMING STUDY: There are few reports of case series of horses with supernumerary cheek teeth (SCT) that document clinical findings, treatment and long-term outcome. OBJECTIVES: To review the clinical and ancillary diagnostic findings and responses to different treatments in horses with SCT. METHODS: The case records of 15 horses were reviewed and long-term outcomes obtained by telephone interview. RESULTS: Fifteen horses with a total of 24 SCT were identified. Two SCT were incidental findings and were not treated. Clinical signs were improved or resolved in 11 of 13 of the teeth treated conservatively and all 6 treated by extraction had a favourable outcome. Four horses were subjected to euthanasia within a short period of diagnosis, either due to a poor prognosis at the outset or failure to respond to initial conservative treatment. CONCLUSIONS: Some SCT are chance findings and do not cause clinical signs. In those instances where clinical signs of dental disease are mild, conservative treatment including the management of diastema and reduction of overgrowths is often effective. Horses with severe clinical signs attributable to an SCT are likely to require extraction of the offending tooth. POTENTIAL RELEVANCE: An SCT is an uncommon dental anomaly but should be considered in the differential diagnosis of cases with signs of severe dental disease. The preferred management for SCT is very variable and determined by the severity of the associated changes, but ranges from conservative measures through forceps extraction per os to major facial flap surgery.

Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 1: Maintenance of surgical arytenoid abduction and complications of surgery.

REASONS FOR PERFORMING STUDY: Laryngoplasty (LP) is currently the most common surgical treatment for equine laryngeal paralysis, however, there have been no reports quantifying the degree of retention of arytenoid abduction following LP. Additionally, the complications of LP have been poorly documented. OBJECTIVES: To record the degree of arytenoid abduction retention following LP and to accurately document all complications of surgery. METHODS: A study (1986-1998) of 200 horses of mixed breed and workload, median age 6 years (prospective 136 cases and retrospective 64 cases) undergoing LP (using 2 stainless steel wires) and combined ventriculocordectomy was undertaken; 198 owners completed questionnaires, a median of 19 months following surgery. The degree of arytenoid abduction achieved was endoscopically, semi-quantitatively evaluated using a 5-grade system, at 1 day, 7 days, and 6 weeks after surgery. RESULTS: On the day following LP, 62% of horses had good (median grade 2) arytenoid abduction, 10% had excessive (grade 1), and 5% had minimal (grade 4) abduction (overall-median grade 2). Due to progressive loss of abduction, moderate (median grade 3, range 1-5) abduction was present overall at 1 and 6 weeks after LP. Further surgery was required to re-tighten prostheses in 10% of cases with excessive loss of abduction, or to loosen prostheses in 7% of horses which had continuing high levels of LP abduction and significant post operative dysphagia. LP wound problems (mainly seromas and suture abscesses) were reported to last < 2 weeks in 9% of cases, < 4 weeks in 4% and > 4 weeks in 4%. The (partially sutured) laryngotomy wounds discharged post operatively for < 2 weeks in 22% of cases, < 4 weeks in 7% and for > 4 weeks in 2%. Coughing occurred at some stage post operatively in 43% of cases and its presence correlated significantly with the degree of surgical arytenoid abduction. This coughing occurred during eating in 24% of cases and was not associated with eating (or dysphagia) in the other 19% of cases. Chronic (> 6 months duration) coughing occurred in 14% of cases, but appeared to be due to intercurrent pulmonary disease in half of these horses. CONCLUSIONS: Suturing the cricotracheal membrane allows most laryngotomy wounds to heal quickly. Laryngoplasty wound problems were of little long-term consequence when stainless steel wire prostheses were used. POTENTIAL RELEVANCE: A significant loss of LP abduction occurs in most horses in the 6 weeks following surgery and efforts should be made to find ways to prevent such loss. However, excessive LP abduction is associated with post operative dysphagia and coughing.

Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 2: Owners' assessment of the value of surgery.

REASONS FOR PERFORMING STUDY: There is continuing debate on the clinical benefit of laryngoplasty (LP) in the treatment of equine laryngeal paralysis. In particular, there is little information available on the clinical value of this surgery in older horses, in non-Thoroughbreds or in sports or pleasure horses; nor on the relationship between the degree of LP abduction achieved and the clinical value of LP. OBJECTIVES: To evaluate the owner's assessment of the value of LP (and combined ventriculocordectomy) in an older, mixed breed and mixed workload population of horses and to also assess the relationship between the degree of LP abduction present and the clinical value of this surgery. METHODS: A study (1986-1998) of 200 horses of mixed breed and workload, median age 6 years (prospective 136 cases and retrospective 64 cases) undergoing LP and ventriculocordectomy was undertaken. The degree of laryngoplasty abduction achieved and maintained was semiquantitatively evaluated using a 5-grade system. RESULTS: A survey of 198 owners, a median of 19 months after LP surgery, showed that 91% of cases had returned to full work and 3% to reduced work, including 95% of horses with good (Grade 2) laryngoplasty abduction at 6 weeks after surgery, 91% with moderate (Grade 3) abduction, 88% of cases with minsimal (Grade 4) abduction and just 25% of cases with total loss of surgical abduction (Grade 5). Once back in work, 73% of cases were reported to make no abnormal exercise-related noises ('noises') at exercise, with reduced 'noises' reported in some of the 21% of horses that still made 'noises'. In the other 6% of cases, owners were unsure if 'noises' were present. The absence or presence of 'noises' once back at work correlated significantly with the degree of surgical arytenoid abduction present at 6 weeks after LP. Once back in work, 'noises' were less commonly detected in sports and pleasure horses (absent in 76% of cases) than in racehorses (absent in 60%) of cases. Exercise performance following surgery was reported to be markedly increased in 75% of cases, with 10% showing no difference in exercise performance, 3% showing worse performance, and owners unsure of any effect on exercise performance in 13% of cases. Improved work was reported in 70% of sports and pleasure horses and in 67% of racehorses. Overall, 86% of owners believed LP was worthwhile, 7% believed it was not worthwhile and 6% were unsure of its value. Surgery was reported to be of most benefit to sports horses (e.g. reported worthwhile for 100% of show jumpers) and of least benefit to National Hunt (long distance) racehorses where 71% of owners believed it to be worthwhile. CONCLUSIONS AND POTENTIAL RELEVANCE: Most horse-owners believe that LP and combined ventriculocordectomy are of clinical value, especially in sports and pleasure horses. Large scale physiological studies on clinical cases, pre- and post operatively, are required to examine more critically the value of such surgery.

Clinical and endoscopic evidence of progression in 152 cases of equine recurrent laryngeal neuropathy (RLN).

Examination of the long-term histories and clinical findings was performed in 351 horses suffering from recurrent laryngeal neuropathy (RLN) to examine for possible evidence of progression of this disorder. Fifty-two out of 351 cases (15%) had evidence of progression of the degree of laryngeal dysfunction over a median period of 12 months (range 1.5-48 months) with the onset of progression occurring at median age 7 years. In 30 cases, there was both endoscopic (median deterioration of 3 endoscopic grades; range 1-5 grades) and clinical evidence, with 29 (97%) of these horses concurrently developing sudden-onset, abnormal exercise-related respiratory 'noises' and 13 (43%) concurrently reporting reduced exercise performance. In the remaining 22 horses there was solely clinical evidence of RLN progression, including the sudden onset of abnormal exercise-related respiratory sounds in 16 (73%) and the worsening of such sounds in 6 (23%), associated with reduced exercise performance in 13 (59%) of these 22 cases. Endoscopically, 13 (59%) of the latter 22 cases had marked (total or almost total) RLN that did not appear compatible with their previous exercise-performance histories. This evidence of progression of RLN may be of particular significance in disputes concerning horses that are apparently normal at pre-purchase examination but are later shown to have RLN and also in the surgical treatment of less severe cases of RLN.

Laryngeal paralysis: a study of 375 cases in a mixed-breed population of horses.

Referred cases (n = 375) of laryngeal paralysis (1985-1998) from a mixed-breed equine population included 351 (94%) cases of recurrent laryngeal neuropathy (RLN) (idiopathic laryngeal hemiplegia) and 24 cases (6%) of laryngeal paralysis from causes other than RLN. Laryngeal movements were classified endoscopically into one of 6 grades, in contrast to the usual 4 grades. The RLN cases had a median grade 4 laryngeal paralysis, of which 96% were left-sided, 2% right-sided and 2% bilaterally affected. RLN cases included 204 (58%) Thoroughbred, 96 (27%) Thoroughbred-cross, 23 (7%) draught, 16 (5%) Warmbloods and 10 (3%) other breeds, including only 4 (1%) ponies. The median age of RLN cases at referral was 6 years (range 2-12) and their median height was 170.2 cm. The work of RLN horses included National Hunt racing (42%), flat racing (1%), hunting (19%), eventing (16%) and miscellaneous work (22%). Reported presenting signs in RLN-affected horses included abnormal exercise-related respiratory sounds in 90% and reduced exercise tolerance in only 64%. However, many horses were referred before their exercise tolerance could be fully assessed. Forty percent of the RLN cases had intercurrent disorders, including 10% with additional upper respiratory and 7% with lower respiratory tract diseases. The 24 nonidiopathic RLN cases included 12 with bilateral laryngeal paralysis, 11 (92%) of which were ponies. Bilateral laryngeal paralysis occurred with hepatic encephalopathy in 7 cases and following general anaesthesia in 2 cases. The 12 cases of acquired unilateral laryngeal paralysis included 7 caused by guttural pouch mycosis.

A long-term study of 277 cases of equine sinonasal disease. Part 1: details of horses, historical, clinical and ancillary diagnostic findings.

The clinical and ancillary diagnostic findings in equine sinnasal disease were studied. The diagnoses in 277 referred (1984-1996) cases of equine sinonasal disease included the following (% all cases): 67 cases (24.2%) primary sinusitis, 61 (22.0%) dental sinusitis, 37 (13.4%) sinus cysts, 22 (7.9%) sinonasal neoplasia, 21 (7.6%) progressive ethmoid haematoma, 17 (6.1%) sinonasal trauma, 13 (4.7%) sinonasal mycosis, 11 (4.0%) rostral maxillary cheek tooth infection, 7 (2.5%) sinonasal polyps, 7 (2.5%) cases of nasal epidermal inclusion cysts and 14 (5.1%) miscellaneous sinonasal disorders. Many disorders showed similar clinical signs including nasal discharge (present in 88% of all cases) and facial swelling (46%). Most disorders were chronic, with a median duration of signs of 12 weeks (range 3 days- 6 years) prior to referral. Sinus cysts and sinonasal neoplasia were significantly (P<0.05) more frequently associated with gross distortion of the nasal passages and facial bones than the other sinonasal disorders. Endoscopic changes were detected per nasum in 91% of cases, but contributed to the exact diagnosis in only 20%. Radiography revealed abnormalities in 81% of cases but was diagnostically useful in only 36%. Sinoscopy was diagnostically useful in 70% of the 61 cases where used.

A long-term study of 277 cases of equine sinonasal disease. Part 2: treatments and results of treatments.

The treatments of 277 horses with equine sinonasal disease (1984-1996), described by Tremaine and Dixon (2001), are reported here. Long-term (median duration 24 months) outcomes of treatment of the more common disorders were good, with 92% of horses with sinonasal mycosis, 84% with primary sinusitis, 82% with sinus cysts, 78% with dental sinusitis and 75% with sinonasal trauma reported to have complete remission of clinical signs. However, only 33% of horses with progressive ethmoidal haematoma (PEH) and 12% with sinonasal neoplasia reported long term remission of clinical signs.

Equine dental disease. Part 3: A long-term study of 400 cases: disorders of wear, traumatic damage and idiopathic fractures, tumours and miscellaneous disorders of the cheek teeth.

Of 400 horses referred because of dental disorders, 349 cases were diagnosed as suffering from primary disorders of their cheek teeth. Details of 104 of these cases are presented, including 44 cases with abnormalities of wear, 26 cases with traumatic damage, 24 cases with idiopathic fractures and 10 cases with miscellaneous cheek teeth disorders including oral tumours. The long-term response to treatment was excellent in most cases, even in cases with residual secondary periodontal disease.

Effect of long-term administration of an injectable enrofloxacin solution on physical and musculoskeletal variables in adult horses.

OBJECTIVE: To evaluate clinical safety of administration of injectable enrofloxacin. DESIGN: Randomized controlled clinical trial. ANIMALS: 24 adult horses. PROCEDURES: Healthy horses were randomly allocated into 4 equal groups that received placebo injections (control) or IV administration of enrofloxacin (5 mg/kg [2.3 mg/lb], 15 mg/kg [6.8 mg/lb], or 25 mg/kg [11.4 mg/lb] of body weight, q 24 h) for 21 days. Joint angles, cross-sectional area of superficial and deep digital flexor and calcaneal tendons, carpal or tarsal osteophytes or lucency, and midcarpal and tarsocrural articular cartilage lesions were measured. Physical and lameness examinations were performed daily. Measurements were repeated after day 21, and articular cartilage and bone biopsy specimens were examined. RESULTS: Enrofloxacin did not induce changes in most variables during administration or for 7 days after administration. One horse (dosage, 15 mg/kg) developed lameness and cellulitis around the tarsal plantar ligament during the last week of administration. One horse (dosage, 15 mg/kg) developed mild superficial digital flexor tendinitis, and 1 horse (dosage, 25 mg/kg) developed tarsal sheath effusion without lameness 3 days after the last administration. High doses of enrofloxacin (15 and 25 mg/kg) administered by bolus injection intermittently induced transient neurologic signs that completely resolved within 10 minutes without long-term effects. Slower injection and dilution of the dose ameliorated the neurologic signs. Adverse reactions were not detected with a 5 mg/kg dose administered IV as a bolus. CONCLUSIONS AND CLINICAL RELEVANCE: Enrofloxacin administered IV once daily at the rate of 5 mg/kg for 3 weeks is safe in adult horses.

Equine dental disease part 2: a long-term study of 400 cases: disorders of development and eruption and variations in position of the cheek teeth.

Of 400 referred horses with dental disorders, 349 cases suffered from primary disorders of their cheek teeth, ninety of these from disorders of development or eruption, or displacements. These included 20 cases with rostral maxillary and caudal mandibular cheek teeth overgrowths, 16 with diastemata, 15 with grossly enlarged mandibular 'eruption cysts', 4 with grossly enlarged maxillary cheek teeth 'eruption cysts', 10 cases with supernumerary cheek teeth and 23 cases with displaced cheek teeth. These displacements were believed to be developmental in 16 cases and acquired in the remaining 7 cases. Long-term response to treatments, that included removal of overgrowths and extraction of teeth with deep secondary periodontal disease was excellent for most disorders except diastemata.

Histopathological findings in equine sinonasal disorders.

Biopsies collected from 79 referred cases of equine sinonasal disease, including 27 horses with primary sinusitis, 10 with secondary dental sinusitis, 19 with sinus cysts, 11 with progressive ethmoid haematomata (PEH), 4 with false nostril epidermal inclusion cysts, 4 with sinonasal polyps, 3 with sinonasal mycosis and from 2 control animals were examined histologically. Observations were made on epithelial type and integrity, cellular inflammatory response, fibroplasia and presence of potential pathogens. Chronic inflammatory changes including mucosal thickening, ulceration and significant fibroplasia, were found in the sinus mucosa with most sinus disorders, similar to those found in human chronic sinusitis. Bacteria were variably present on sinusitis mucosae but their aetiological significance was unclear. The presence of apparently irreversible changes including fibroplasia in some of these sinusitis cases may explain their poor or delayed response to treatment. Sinus cysts had histological similarities to human mucocoeles. Progressive ethmoid haematomata showed recent and older haemorrhage, as did sinus cysts (and occasionally some chronic sinusitis sections), but support for a common aetiology between sinus cysts and PEH was absent.