Table of Contents
Introduction
- Wash hands, Introduce self, Patients name & DOB & wrist band, Explain procedure and get written consent
- Common risks: scarring, bleeding, infection, damage to local structures, nerve damage, numbness over area
Preparation part
- Wash hands and apply apron
- Clean a trolley
- Gather equipment onto bottom of trolley (think through what you need in order)
Equipment list
- Sterile pack
- Cleansing snap-sponge (iodine or alcohol/chlorhexidine)
- Sterile drape with hole in centre (or 2-3 drapes without holes in)
- 5ml syringe and 2 needles (1 blunt fill 18G drawing-up needle, 1 orange 25G) for local anaesthetic
- 4mm sterile disposable biopsy punch x1-3
- Suturing instrument kit
- Needle holder
- Toothed forceps
- Non-toothed forceps
- Scissors
- 4-0 Novafil suture (or similar)
- Cotton gauze swabs (used whenever needed throughout procedure to dry/clean sterile area)
- Sterile dressing
- Equipment to be kept outside of the sterile field
- 10ml sterile saline
- Sterile gloves
- 5ml 1% lidocaine (maximum 3mg/kg – note 1ml 1% lidocaine = 10mg) with or without adrenaline
- Sample tubes
- Formalin filled specimen container for histology (must send white page of consent form with this sample)
- Direct immunofluorescence sample container for direct immunofluorescence (if required, e.g. for bullous disorders, vasculitis, or connective tissue diseases; this sample should be from perilesional skin for bullous lesions; skin punch is wrapped in small part of saline soaked gauze inside tube)
- White top universal container for microbiology (if required, e.g. for suspected infection)
- Walk to patient
- Wash hands
- Open sterile pack to form a sterile field on the top of the trolley
- Open packets (without touching the instruments themselves) and drop sterile instruments neatly into the sterile field
- Pour some sterile saline over a gauze so it is moist
- Pick up waste bag from sterile pack without touching anything else and stick to side of trolley
Patient part
Positioning and exposure
- Choose and expose biopsy site
- Ideal areas: arms, thighs, back, abdomen
- Ideally biopsy an established lesion with the most primary inflammatory change (unless blistering/pustular/vasculitic lesion, then early lesions preferred)
- Part of lesion to biopsy
- For large lesions, biopsy the edge of the lesion, the thickest part, or the most abnormal area
- For annular lesions, biopsy the edge of the lesion
- For ulcers, biopsy the edge and include a portion of normal skin
- NB. in bullous skin lesions, the skin biopsy for direct immunofluorescence should be taken from perilesional skin.
- Areas to avoid if possible
- Sites with underlying nerves or blood vessels
- Cosmetic-sensitive areas (e.g. face; shoulders and chest are prone to hypertrophic scarring)
- Areas with high infection risk (e.g. groins, axillae)
- Areas of vascular insufficiency (e.g. lower legs/feet)
- Lesions with secondary features (e.g. infection/crusting)
- Lesions that have been subjected to trauma (e.g. scratched lesions, lesions over joints)
- Position patient comfortably
- Mark biopsy site(s) with a skin pen/indentation
Preparation
- Wash hands
- Apply sterile gloves using sterile technique (open pack on a side surface)
- Sterilize area
- Work from middle outwards in one spiral motion (use cleansing snap-sponge)
- Discard used snap-sponge as it is no longer sterile, but note all equipment used after this (including all needles) can be returned to the sterile field after use
- Apply the sterile drape over the site so that the hole is in the correct place to allow access to the biopsy site
- Anaesthetise area
- Ask assistant to snap open lidocaine bottle and hold open upside-down
- Draw up lidocaine using drawing-up needle on 5ml syringe
- Change to the orange needle and insert at an acute angle to anaesthetise the area of the biopsy site (subcutaneously and slightly deeper; 1-2ml per biopsy site)
Performing the punch biopsy
- Stretch skin perpendicular to resting skin lines
- Push biopsy punch directly into skin, rotating it back and forth, as far as it will go (should go through to subcutaneous fat – a ‘giving way’ feeling marks this point)
- NB. in areas of thin skin, do not go down as far as the periosteum. Avoid areas with underlying nerves or blood vessels.
- Remove biopsy punch
- Press down on either side to elevate skin punch
- Grab skin punch very gently with toothed forceps (avoid crush injury), elevate, and cut off at the base with scissors
- Place skin punch on saline soaked gauze in sterile field
- Suture wound with a single suture (parallel to skin tension lines) – see suturing notes
- NB: leave enough thread on the needle end if need multiple biopsies
- Repeat process if multiple biopsies required (different biopsy required for histology, direct immunofluorescence, and microbiology if required)
- Apply a sterile dressing
- Place samples in specimen tubes as detailed below
To complete
- Thank patient and cover them
- Bin waste and gloves, dispose of sharps safely, clean trolley and wash hands
- Label tubes and send to lab, listed as urgent if rapid result required
- Formalin sample tube (histology) → histopathology
- Must be sent with white page of patient consent form
- Direct immunofluorescence sample tube (direct immunofluorescence) → histopathology (if required)
- Skin punch for this sample should be wrapped in a small part of saline soaked gauze (cut off with scissors)
- White universal sample tube (MC&S) → microbiology (if required)
- Formalin sample tube (histology) → histopathology
- Advice patient sutures must be removed in 10-14 days
- Fully document procedure in patients notes
