8.11 Inspection of Sigmoidoscope Sets

Why It Is a Named Device

A rigid sigmoidoscope set looks simple and is therefore easy to under-inspect. It is in fact a combination of a long, smooth-bore lumen in direct mucosal contact, an optical and illumination path, an air delivery system, and a set of accessories — four different inspection problems in one case. CBSPD names it explicitly for that reason.

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Components of a Rigid Set

Flexible sigmoidoscopes are flexible endoscopes and follow Section 8.5 in full — leak test before immersion, channel brushing and flushing, borescope inspection, angulation testing, and hanging storage.

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Inspecting the Scope Tube

The tube is a lumen that contacts mucosa along its whole length, so it is inspected like a lumen and like a tissue-contact surface.

1. Interior — inspect under good light and, where available, with a borescope. Look for retained soil, scratches, corrosion, and any roughness.
2. Distal rim — must be smooth and unburred. A burr or a nick at the leading edge lacerates mucosa.
3. Exterior — smooth, no dents, no cracks; graduation markings for depth of insertion legible.
4. Proximal fittings — the viewing head, light carrier port, and insufflation port must seat and seal.
5. Size markings legible; sets carry multiple diameters and lengths and they are not interchangeable.

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Obturator

• Matched to its tube by diameter and length. A short or narrow obturator leaves the tube's leading edge exposed on insertion.
• Tip smooth, blunt, and undamaged.
• Slides freely the full length and seats correctly at the proximal end.
• Counted as a component: a scope tube without its obturator is an incomplete set.

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Illumination and Optics

• Light carrier / fibre bundle: shine light through and inspect for black dots indicating broken fibres, as with any fibre-optic component; check the ferrule faces for blackening and the jacket for cuts.
• Distal light exit clean and unobstructed.
• Viewing window / lens: clear, unscratched, undamaged, and sealing — a window that does not seal makes insufflation impossible.
• Connections to the light source: correct adapter, intact threads.

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The Insufflation System

This is the component most often released defective because it is the least instrument-like.

1. Inspect the bulb for cracks, splits, perforations, hardening, stickiness, and loss of elasticity.
2. Inspect the tubing for cuts, kinks, hardening, and secure attachment at both ends.
3. Inspect the valve where fitted for free operation.
4. Pressure check: occlude the outlet and squeeze the bulb — it should resist and hold, then refill when released. A bulb that collapses without resistance, or that will not refill, is failed.
5. Confirm all connectors are present and seat firmly.

A failed insufflation system means the lumen cannot be distended, which means the examination cannot be performed — discovered, if it is not caught in SPD, with the patient already prepared.

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Accessories

• Biopsy forceps: jaw alignment and closure under magnification; cups intact and meeting; actuating mechanism smooth through full travel; shaft straight; lumen (where present) brushed and verified.
• Suction tips and tubing: brushed through, patent, unburred.
• Specimen traps and containers: present, undamaged, and complete with lids.
• Anoscopes / proctoscopes: same tube-and-obturator rules as the sigmoidoscope.

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Processing Notes

• Disassemble completely — tube, obturator, light carrier, viewing head, bulb and tubing — before cleaning.
• The tube is brushed through its full length with a correctly sized brush that exits the far end, then flushed and verified.
• Follow the IFU for method: components differ, and bulbs, tubing, and fibre carriers frequently have restrictions that the steel tube does not.
• Dry fully, including the tube interior and the tubing, before packaging.

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Disposition

The Components and What Each Contributes

A rigid sigmoidoscope set is a small system, and knowing what each piece does explains what can go wrong with it.

The scope tube is a rigid hollow tube, graduated in centimetres along its length so the depth of insertion can be read. The obturator is the blunt-tipped rod inserted through the tube to allow atraumatic insertion, removed once the scope is in position. The light carrier or fibreoptic bundle delivers illumination to the distal end. The eyepiece or viewing window seals the proximal end so the lumen can be insufflated. The insufflation bulb and tubing deliver air to distend the lumen for visualisation. Suction tips, biopsy forceps, and specimen accessories complete the set.

Each is a separate count-sheet line, and a set missing the obturator or the insufflation bulb is unusable.

Inspecting the Tube and Optical Path

Inspect the scope tube inside and out. The distal rim must be smooth and free of burrs, nicks, and cracks, because it is the edge that contacts mucosa on insertion. The interior lumen must be clean along its whole length — hold it to a light and sight through it — and free of scratches, residue, and dents.

Confirm the graduation markings are complete and legible, since the depth measurement they give is recorded in the patient's record. Worn markings are a removal criterion.

Check the light carrier by connecting it and observing even, bright illumination at the distal end; dark speckling indicates broken fibres. Inspect the viewing window for cracks and clarity and its seal or gasket for integrity, because a failed seal means the lumen will not hold insufflation.

Insufflation, Obturator and Processing

Test the insufflation system as a system: squeeze the bulb and confirm air is delivered at the distal end, that the bulb re-inflates, and that the valve holds so air is not simply pushed back out. Inspect the tubing for cracks, splits, and hardening, and confirm the connectors seat firmly. Perished tubing is the most common failure in these sets.

Inspect the obturator for a smooth, undamaged blunt tip, straightness, and correct fit — it must pass through the tube freely and seat correctly without binding. An obturator from another set may fit loosely and defeat the purpose.

Process the set disassembled, with the lumen brushed using a correctly sized brush and verified patent and dry, and reassemble at the bench only to verify fit before packaging as the instructions direct. Because these sets mix rigid metal with optics and elastomer tubing, confirm each component's sterilization method rather than assuming the whole set shares one.