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Singapore Med J 1999; Vol 40(01):

An Audit of Endoscopic Sinus Surgery
S Yeak, J K Siow, A B John

ABSTRACT

Aim of Study: A prospective study was carried out to evaluate the results of endoscopic sinus surgery based on symptom score and endoscopic findings and to evaluate the prognostic factors using an audit form designed by IS Mackay of London.

Methods: Consecutive cases undergoing endoscopic sinus surgery were entered into the study. Pre-operative symptom, computer tomographic and endoscopic scores were recorded. Operations were also evaluated objectively; post-operative symptom and endoscopic scores were recorded at 3, 6 and 12 months. Cases lost to follow-up were interviewed over the telephone and offered free endoscopic assessments. Those who required revision surgery were considered failures and re-entered into the study.

Results: The study comprised 113 cases (108 patients, 60 males and 48 females) with ages ranging from 14 to 80 years (mean 40.4). There were 52 with chronic rhinosinusitis, 46 with nasal polyps, 7 with tumours/inverted papillomata, 5 with acute complicated sinusitis and 3 with fungal sinusitis. Of these, 81.9% of patients with chronic rhinosinusitis or polyps showed an overall improvement of symptoms. Nasal obstruction showed the greatest improvement, followed by rhinorrhoea, loss of smell and headaches and facial pain. Endoscopic improvement was greatest in polyps (83.3%) and oedema (87.0%) but less for discharge (59.4%).

Conclusions: Our results compared well with international series. Computer tomography scoring and the number of revision operations emerged as potential prognostic indicators requiring further evaluation.

Keywords: audit, rhinosinusitis, nasal polyposis, computer tomography, endoscopic sinus surgery

INTRODUCTION

Endoscopic sinus surgery was first popularised by Stammberger using techniques based on the pathophysiological principles described by Messerklinger(1) in 1978. Many international papers

have reported high success rates of between 80% - 98% clinical improvement based on symptoms(2-9). This has been substantiated by objective assessments of the results of endoscopic sinus surgery by Lund and Scadding(10,11) in 1991 and 1994.

A prospective study was conducted using an audit form designed by IS Mackay of London which is based on a staging system described by Lund and Mackay(12) in 1993. Although several other staging systems have been proposed(7,13), we chose this system for its simplicity and reproducibility since our data collection involved several surgeons. This system was accepted with modifications at a consensus meeting on rhinosinusitis by an international and multidisciplinary group of clinicians in Princeton, USA in July 1993.

a. Symptom score

The patients’ top 3 symptoms were recorded. Visual analogue scores on a scale of 0 - 10 were also recorded for the following 4 groups of symptoms: nasal obstruction/congestion, anterior/posterior nasal discharge, disorders of smell/taste and facial pain/headaches.

b. Endoscopic score

Endoscopic appearances were quantified on a 0 _ 2 point basis for the presence of polyps (0 = none; 1 = confined to middle meatus; 2 = beyond middle meatus), discharge (0 = none; 1 = clear and thin; 2 = thick and purulent), oedema (0 = none; 1 = mild oedema, 2 = gross oedema), scarring/adhesions (0 = none; 1 = adhesion bands; 2 = closed cavity) and crusting (0 = none; 1 = mild crusting; 2 = gross crusting).

c. Computer tomographic score

Staging of disease relied predominantly on computer tomographic (CT) scan assessment. Each sinus group (frontal, anterior ethmoids, posterior ethmoids, maxillary and sphenoid) was graded between 0 - 2 (0 = no abnormality; 1 = partial opacification; 2 = total opacification). The ostiomeatal complex was scored as ‘0’ (not obstructed) or ‘2’ (obstructed). This gave a possible score of between 0 - 12 on each side and an overall total score of between 0 - 24. The presence of anatomic variants - absent frontal sinus, concha bullosa, paradoxically bent middle turbinate and Haller cell - was noted but did not alter the score.

Operative scoring
Scores were recorded as ‘0’ (not done) and ‘1’ (done) for the following procedures: uncinectomy, middle meatal antrostomy, anterior ethmoidectomy, posterior ethmoidectomy, sphenoidectomy, clearance of frontal recess and reduction of middle turbinate. This produced a possible total score of between 0 - 14 (0 -7 for each side).

Post-operative scoring
Assessments were carried out at 3, 6 and 12 months following surgery. The top 3 symptoms were followed up and recorded as A (absent), B (better), S (same) and W (worse). The visual analogue scores (0 - 10) and endoscopic scores (0 - 2) were also recorded using the above scoring system.

Follow-up
Patients lost to follow-up were called up by the principal investigator and interviewed over the telephone. They were also given appointments to go for endoscopic reassessment. Whereas other studies often include revision surgery (when necessary) in reporting the overall success, we did not because of the short period of follow-up. All cases needing revision surgery were classified as "failures" and re-entered into the study.

Operation statistics
Most operations were carried out under general anaesthesia (80.5%) and the duration of surgery ranged from 25 to 195 minutes (mean 94.4, SD 43.2).

Post-operative medication
No post-operative analgesics were given to 31.0% of patients whilst 48.0% had adequate pain relief with paracetamol. Ponstan (15.0%) and Synflex (6.0%) were the other analgesics used. For post-operative antibiotics, the majority of cases were given Bactrim (35.0%) or Amoxil (31.0%). Augmentin (17.0%), Unasyn (5.0%) and Klacid (5.0%) were also used. About a third of patients (36.6%) were given oral steroids post-operatively for a variable period.

Complications
Only 3 significant complications were recorded. One patient had a post-operative secondary haemorrhage which was easily controlled. Another patient developed temporary blindness post-operatively which rapidly recovered following removal of the nasal pack. In this case, the nasal pack was coated with tetracycline ointment which may have caused fluid accumulation and back pressure on an exposed optic nerve in an opened Onodi cell. There was one case of cerebrospinal fluid leakage following endoscopic biopsy of an ossifying fibroma of the ethmoid. The patient subsequently underwent open surgery to repair the leak and made a good recovery.

Surgical outcome

a. Based on symptoms

The main complaints (first symptom) were predominantly nasal obstruction or congestion (40.6%) and rhinorrhoea (25.5%) (Table I). Improvement in the main complaint for patients with chronic rhinosinusitis and nasal polyposis was seen in 78.3% of patients whilst the overall symptomatic improvement was 81.9% (Table II). However, it is important to note that main complaints were completely eliminated in only 39.8%. Also, only 22.9% of patients were totally symptom free after their surgery. There was no significant difference between results in chronic rhinosinusitis and nasal polyposis, although a higher failure rate might have been expected in cases of nasal polyposis. This could be due to the relatively short follow-up period in our study.

b. Based on visual analogue scores

Visual analogue scores were improved significantly (p< 0.001) for all the symptoms (Table III). Predictably, nasal obstruction or congestion showed the most improvement, followed by nasal discharge, disorders of smell or taste as well as headaches and facial pain.

c. Based on endoscopic scores

We included a column to record the surgeon’s opinion of the operative outcome. It was interesting to note that the surgeon’s assessment (72.9%) was lower than the patient’s perception of improvement (81.9%). This discrepancy may have been biased by the post-operative endoscopic findings. Although there were less polyps in 83.3% of patients and oedema had improved in 87.0% of patients, less discharge was noted in only 59.4% of patients (Table IV). Total absence of polyps was seen in 64.6% of patients who had small polyps pre-operatively and in only 54.2% of patients who had gross polyposis. This suggests that endoscopic findings might be a better indicator of the possibility of future recurrence than patients’ symptom scores. No oedema was present in less than half the patients and no discharge was seen in over 30% of patients. Endoscopy also showed that 29.9% had developed post-operative adhesions, underlining the importance of meticulous post-operative toilet. Crusting was seen in only 7.7% of patients and does not appear to be a major problem in our warm and humid climate.

 

a. Computer tomographic score

The CT scores in the audit showed a relatively normal distribution. For the purpose of evaluating the impact of CT staging on prognosis, we divided the range of scores into percentiles. Scores below the 25th percentile were placed in category 1, those between the 25th to 75th percentile, in category 2 and those above the 75th percentile, in category 3. This system was used because it was felt that the extremes of scores would have more significance on prognosis. In category 1, 89.5% of patients showed improvement, 84.1% improved in category 2, and 78.3% in category 3. However these results were not statistically significant (p = 0.33) as a prognostic guide. This could be due to the relatively short follow-up period as well as the small numbers studied.

b. Operative score

The operative scores also showed a normal distribution. The scores were similarly divided into 3 categories using the 25th and 75th percentiles. No prognostic trend was evident.

c. Revision surgery

There was no overall difference in success rates between those who had undergone revision surgery (78.1%) and primary cases (84.3%). Prognosis seemed to worsen if multiple revisions (60.0%) were needed compared to those who had undergone only one revision (86.4%). This was however not statistically significant due to the small numbers.

d. Grade of surgeon

The degree of seniority of the surgeon seemed to affect the prognosis significantly (p< 0.05). The outcome was worse in cases performed by senior surgeons but this could be partially attributed to the greater complexity of operations allotted to them.

e. Post-operative systemic steroids

Post-operative oral steroids did not improve results. Also, patients placed on oral steroids did not have worse disease to begin with.

 

a. "Inverted papilloma"/tumours

One patient had ossifying fibroma and "inverted papilloma" was the pre-operative diagnosis in 5 patients with subsequent histological confirmation in 3 patients. Of these, one was well after the first operation, one required a revision operation (registered as 2 cases) whilst the third patient was found to have bilateral disease and was offered open surgery. The remaining 2 patients were found to have undifferentiated carcinoma and adenoid cystic carcinoma and were treated by radiotherapy and surgery respectively.

b. Acute complicated sinusitis

Five patients presented with acute complicated sinusitis. Of these, 2 patients suffered from orbital abscesses, one had orbital cellulitis with meningism, one had meningitis and one had a frontal pyocoele. All the above patients were treated successfully endoscopically except for one of the patients with orbital abscess, who was found to have an underlying lacrimal abscess, and underwent open drainage. All the patients have remained well on follow-up.

c. Fungal sinusitis

Three patients suffered from fungal sinusitis. One patient had aspergillus sinusitis showing invasion on histology and underwent systemic anti-fungal therapy which was stopped because of abnormal liver enzymes. She subsequently left the country for Hong Kong where she had revision surgery. The other 2 patients were well on follow-up.

1. Four out of five patients will experience significant improvement in their symptoms although they may not be cured of the disease.

2. One-third of patients will derive great overall benefit from the operation, another third will also benefit after adequate post-operative medication, and the remaining third are likely to require long term medication or even revision surgery.

3. The local complication rate from endoscopic sinus surgery is low and largely avoidable with proper training of surgeons and the use of CT scans in the pre-operative assessments.