METHODS
The study comprises a prospective cohort analysis comparing short course
antimicrobial therapy +/- early surgical debridement versus prolonged
course antimicrobial therapy alone in patients with NOE. The treatment
protocol was approval by the Head & Neck Clinical Governance team at
South Tyneside and Sunderland NHS Foundation Trust. All patients
admitted with a clinical diagnosis of NOE to Sunderland Royal Hospital
(SRH) between January-September 2019 were included.
Factors evaluated on admission included duration of symptoms, any
relevant microbiology results, antibiotic therapy to date, history of
ear syringing, patient pain score (1-10), cranial nerve palsies, and
medical comorbidities (e.g. diabetes mellitus).Baseline investigations,
including an ear swab, baselines blood tests (FBC, U&E, LFT, glucose,
HbA1c, CRP, ESR), and a CT temporal bone, were performed for each
patient.
In all cases the ear was examined by a senior member of the ENT team
(registrar or consultant) and the canal was given a staging score (see
Fig. 1):
Stage 1 = Normal or near normal ear canal.
Stage 2 = All of tympanic membrane visible, abnormal ear canal
with granulation, polyp or swelling.
Stage 3 = more than 50% of tympanic membrane visible, due to
polyp, granulation or swollen ear canal.
Stage 4 = less than 50% of tympanic membrane visible, due to
polyp, granulation or swollen ear canal.
A significant improvement was defined as an improvement of 2 stages
(i.e. stage 4 to stage 2, or stage 3 to stage 1).
A novel CT grading system was proposed to grade the degree of
osteomyelitis (see Fig. 2):
Stage 1 = Soft tissue swelling , no osteomyelitis.
Stage 2 = Localised osteomyelitis to ear canal
Stage 3 = Evidence of inflammatory disease extending beyond ear
canal, but not extending out of temporal bone.
Stage 4 = Disease extending beyond temporal bone OR presence of
cranial nerve abnormalities.
If there were cranial nerve deficits, or the CT scan was stage 3/4, or
the diagnosis was unclear, then an MRI scan was requested to evaluate
soft tissue extent and meningeal involvement. Where the duration of
antibiotics was to be extended beyond 6 weeks a gallium and bone scan
was undertaken to extent of evaluate resolution and monitor treatment.
Patients were routinely commenced on intravenous piperacillin-tazobactam
and gentamicin in combination. Review by a single surgeon (PA), based
upon a database of previous NOE outcomes, determined whether patients
were then enrolled on short course (2 weeks) +/- early debridement
versus long course (6+ weeks) intravenous antimicrobial therapy.
Review of historical data (unpublished) suggested that the following
parameters conferred a good prognosis:
- Absence of comorbidities
- Short duration of preceding symptoms
- Resolution of pain score down to patient reported score of 0/10 within
4 days
- Moving down 2 steps on otoscopy grading scale within 1 week
- CT findings limited to grade 1 or 2
Patients who met these criteria were enrolled on 2 weeks of intravenous
(short course) antimicrobial therapy, and were subsequently switched to
oral ciprofloxacin for a further 4-week course of treatment. All other
patients were assigned to long course (6 weeks intravenous)
antimicrobial therapy either had their entire treatment as an inpatient
or administration in the community via a long line inserted prior to
discharge.
Surgical intervention was considered only in selected circumstances;
specifically:
A) Presence of an ear canal lesion that fails to respond to treatment
after 1 week. In this case a biopsy with or without debridement
wasoffered.
B) If at the end of treatment there was an area of necrotic bone that
had not epithelised, or a bony sequestrum was present, then surgical
removal wasoffered.
C) Early in course of disease for pain relief where this failed with
improve with medical therapy alone.