Conditions: Pain
Keywords: Pain Bone marrow aspiration trephine biopsy
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 70
Healthy volunteers: no

Brief summary:
The approach of this study will be to answer the question does high-frequency stimulation Trans-Cutaneous Electrical Nerve Stimulation (TENS) alleviate the pain experienced during the bone marrow sampling procedure in addition to the standard analgesia given (ie. local anaesthetic with or without inhaled nitrous oxide).

Null hypothesis: TENS does not alleviate the pain experienced during the bone marrow sampling procedure in addition to the standard analgesia given

Detailed description:
Patients in whom a bone marrow biopsy is planned will be randomised to one of two groups - a control-TENS group where the TENS machine will be set at the lowest sensory threshold and an intervention-TENS group where the TENS machine will be set at a recognised analgesic level (\>50 Hertz (Hz) and below the pain threshold for the patient) (Bennett et al. 2011). The identity of the TENS type will be concealed from both the patient and the doctor performing the biopsy. The primary outcome will be pain and this will be recorded by the patient immediately after the procedure using a validated numerical scale (0-10). All patients will receive standard pain relief (ie. local anaesthetic with or without inhaled nitrous oxide).

The benefit of this study is to establish whether or not TENS can benefit patients as an additional, safe, non-invasive and inexpensive method of pain relief during this frequently painful procedure.

Arms:
arm 1: The Intervention-TENS group will have 2 electrodes applied proximal to the painful area along neuro-anatomical distribution (electrode-one placed 5cm superior and 2cm medial to the posterior superior iliac spine and electrode-two placed 5cm medial to the posterior superior iliac spine) in the same way as the control-TENS group.

The concealed electrical parameter in this group will be within the therapeutic window, that is, well above the sensory detection threshold but below the pain threshold giving a "strong but comfortable sensation". From previous studies, this is likely to be 50-110Hz.

The device will be activated prior to entry into the treatment room and 2 minutes before administration of local anaesthetic and for 2 minutes after removal of the biopsy needle. This will cover the expected duration of pain as assessed in the pilot study.

All patients will receive standard pain relief (ie. local anaesthetic with or without inhaled nitrous oxide) arm 2: Patients in the CT group will have 2 gel-electrodes applied proximal to the sampling area (usually the right posterior superior iliac crest).

The Control-TENS device will be identical in appearance to the "Intervention-TENS" device with a functioning display panel. The concealed electrical parameter in this group will be titrated to and set at the sensory detection.

All patients will receive standard pain relief (ie. local anaesthetic with or without inhaled nitrous oxide)

Interventions: intervention 1: Trans-cutaneous Electrical Nerve Stimulation (TENS) intervention 2: Standard pain relief (ie. local anaesthetic with or without inhaled nitrous oxide)
Intervention descriptions: intervention 1: Patients in whom a bone marrow biopsy is planned will be randomised to one of two groups - a Placebo Comparator group where the TENS machine will be set at the lowest sensory threshold and an Active Comparator group where the TENS machine will be set at a recognised analgesic level (\>50Hz and below the pain threshold for the patient). intervention 2: All patients will receive standard pain relief (ie. local anaesthetic with or without inhaled nitrous oxide)

Protocol document: