Mismanagement of diagnostic injections risks cord damage

Mrs J was a 32-year-old female patient with a long history of neck pain following a road traffic accident. The pain was localised to the left side of the neck and left shoulder, with only very occasional paraesthesia in her left hand. Despite regular analgesics and exercises, the pain was still troublesome and she was keen for a specialist opinion.

Mrs J was referred to Dr M, a pain consultant. Dr M noted slight restriction in neck movement on the affected side and elicited tenderness over the left C5/6 and C6/7 facet joints. Imaging revealed fusion of the C3 and C4 vertebrae and some loss of normal cervical spine curvature, but the vertebral bodies and spaces remained otherwise well-preserved.

Dr M recommended C5/6 and C6/7 facet joint treatment and told Mrs J that there was a 50% chance of getting long-term pain relief. He suggested two diagnostic injections with local anaesthetic followed by radiofrequency lesioning if benefit was felt. Dr M went through the risks of the procedure with Mrs J, including lack of benefit, relapse of pain, infection and damage to nerves.

Mrs J returned for the first of the two diagnostic blocks. The block was performed in the lateral position and Dr M injected a mixture of 0.5% levobupivacaine and triamcinolone. The block provided good pain relief and Mrs J felt it was easier to move her neck.

Mrs J later returned for the second diagnostic injection. Mrs J was placed in the prone position and local anaesthetic infiltrated into the skin. Using biplanar fluoroscopy, 22G spinal needles were inserted toward the C5/6 and C6/7 facet joints. Dr M then attempted to inject a mixture of lignocaine and triamcinolone at the lower level. Unfortunately, as soon as Dr M started the injection the patient jumped with pain and her left arm twitched. The procedure was abandoned.

Despite a normal neurological examination immediately after the procedure, the patient later the same day developed numbness in her left arm and right leg. She also complained of headache when sitting up, as well as pain in her left neck and shoulder. As she felt dizzy on standing, Dr M decided to admit Mrs J for overnight monitoring and analgesia.

The next morning Mrs J was no better. She felt unsteady on her feet and complained of a burning sensation in her right leg, as well as weakness and shooting pains in her left arm.   Dr M decided that a second opinion was required and referred Mrs J to a neurosurgical colleague. An MRI was arranged, which unfortunately demonstrated signal change in the cord at a level consistent with the intended facet joint injection.

Over time, the MRI changes improved but Mrs J continued to suffer from terrible neuropathic pain. It affected many aspects of her daily life and she found it difficult to return to work as she was not able to sit for any length of time. A spinal cord stimulator was inserted by another pain specialist to try and help with the pain, but this was largely unsuccessful and was later removed.

Mrs J subsequently lost her job and, following that, decided to bring a claim against Dr M.

Expert opinion

The case was reviewed for Medical Protection by Dr F, a specialist in pain management. Dr F was of the opinion that the initial assessment and management plan were entirely appropriate. She was somewhat critical of the approach used by Dr M for the diagnostic injection as it was not consistent with the planned approach for the radiofrequency lesioning and, in her opinion, more likely to be associated with the possibility of damage to the spinal cord. She also felt that the use of triamcinolone in the diagnostic injections could be criticised, as injection of particulate matter into the spinal cord is known to be associated with a higher risk of cord damage.

Dr W, an expert neuroradiologist, was concerned about the images he reviewed from the second diagnostic injection. He concluded that neither needle was within the respective facet joint and that the lower needle tip was within the spinal canal at the level of C5, less than 1cm from the midline. Dr W also confirmed that the MRI abnormality corresponded with the position of the lower needle tip.

Dr F concluded that insufficient images were taken to satisfactorily position the needles. She also noted that only 40 seconds had passed between the images taken for the first and second needle insertions, inferring that the procedure had been carried out with some haste.

Medical Protection then instructed a causation expert to comment on Mrs J’s progression of symptoms. Professor I concluded that the development of neuropathic pain in the right limb was understandable, although the disabling effects were more than he would have expected. Whilst the patient did have a history of neck pain, the patient’s symptoms were consistent with a lesion affecting the spinothalamic tract on the contralateral side of the cervical spinal cord.

The case was considered indefensible and was settled for a high sum.

Learning points

• Although it is commonplace for a doctor to assume multiple roles, this case highlights the risks during an individual procedure. Dr M was acting as an anaesthetist providing sedation, analgesia and reassurance, whilst at the same time carrying out the facet joint injections.
• Although Dr M warned the claimant about the possibility of nerve damage, this does not mean that a defence can necessarily be made. Both the expert pain consultant and radiologist concluded that neither needle was positioned as tended prior to the injection and that the lower needle tip was clearly within the spinal canal and thus potentially within the substance of the cord.
• The experts were of the opinion that a pain medicine consultant should be confident in interpretation of live radiological imaging including needle trajectory and accurately determine needle trajectory and position prior to performing the procedure. It is important to allow the necessary time regardless of other pressures and to follow guidelines published by professional societies/bodies, eg, International Spinal Injection Society. There is a body of opinion that advises against the use of particulate steroid injections in the cervical area.
• When an elective procedure or service has been offered to a patient, the practitioner may feel an obligation to fulfil this, even when they may not be entirely confident about doing so. Where there is any doubt or concern, it is far better to abandon the procedure or seek a second opinion, particularly where a mistake may lead to a serious complication.