An 18-year-old male with fistulizing Crohn's disease involving the ileocolonic region
and rectum had a right-sided intersphincteric fistula at the 11 o'clock position,
managed previously by endoscopic seton placement.[1 ] After three induction doses of infliximab, he presented with pain, induration, and
purulent discharge from the left perianal region (at the 3 o'clock position). The
next infliximab dose was due in 1 week.
Point-of-care transperineal ultrasound (TPUS; Linear probe 2–9 MHz, Samsung RS80 EVO,
Samsung India Electronic Pvt. Ltd.) revealed a 10 × 9 × 9 mm hypoechoic abscess without
fistulous communication ([Fig. 1A, B ]). Accurate point-of-care TPUS avoided the need for costly magnetic resonance imaging
(MRI) pelvis, which is often requested before intervention and can delay treatment.
On the same day, under conscious sedation, endoscopic freehand fistulotomy was performed
using a needle knife (Boston Scientific, Marlborough, United States) connected to
an electrosurgical generator (VIO 300D, ERBE Elektromedizin GmbH, Tübingen, Germany)
with Endocut I current (effect 3, cut duration 1, cut interval 3).[2 ] The knife was held freehand between the index finger and thumb like a pen, rather
than through-the-scope, to make two stellate mucosal incisions over the indurated
area, facilitating pus drainage ([Fig. 1C, F ]; [Video 1 ]).
Video 1 Point-of-care transperineal ultrasound localizing a small left perianal abscess in
Crohn's disease, followed by freehand endoscopic fistulotomy with a needle knife,
achieving immediate pus drainage and seton removal in a day-care setting without interrupting
biologic therapy.
Fig. 1 (A ) Point-of-care transperineal ultrasound (TPUS) showing a well-defined hypoechoic
lesion in the left perianal region (3 o'clock position). (B ) Color Doppler TPUS confirming absence of significant internal vascularity, consistent
with a small abscess. (C ) Endoscopic view of the left perianal swelling corresponding to the ultrasound finding.
(D ) Initiation of freehand fistulotomy using a needle knife (Boston Scientific, Marlborough,
United States) connected to an electrosurgical generator (VIO 300D, ERBE Elektromedizin
GmbH, Tübingen, Germany) with Endocut I settings (effect 3, cut duration 1, cut interval
3), held between the index finger and thumb like a pen. (E ) Immediate drainage of pus following stellate mucosal incision. (F ) Post-procedure view showing the drained abscess cavity.
The pre-existing seton at the 11 o'clock position was removed to promote closure and
avoid epithelialization of the earlier fistula. Aseptic care with povidone–iodine
dressing and intravenous cefoperazone–sulbactam (1.5 g) plus metronidazole (500 mg)
immediately after the procedure, followed by oral ciprofloxacin (500 mg twice daily
for 8 weeks), was given along with continued infliximab and azathioprine. Although
local antibiograms show only modest fluoroquinolone sensitivity, ciprofloxacin is
routinely used in perianal Crohn's disease protocols for both antimicrobial and anti-inflammatory
benefits, and the patient responded well without adverse effects. The patient was
discharged the same day and received his scheduled infliximab dose without delay.
This allowed safe continuation of biologics without interruption, which is rarely
feasible after surgical drainage. At the 2-month follow-up, the patient had complete
resolution of symptoms (no pain or discharge). Repeat perineal ultrasound confirmed
absence of residual abscess and reduced fistula tract vascularity, while the patient
remained on infliximab maintenance.
