Sympathetically mediated pain in mesothelioma

Our next patient was referred for a second opinion on implantation of an intrathecal morphine pump to treat thoracic pain cause by a left sided mesothelioma. The patient had already had close to full dose radiotherapy towards the left chest and chemotherapy without improvement of his pain. 

His malignancy was known since two years and was clinically in a stable phase. Pain was situated in a segmental area in the posterior aspect of the left chest wall and did not irradiate beyond the posterior axillary line. There were no neuropathic pain characteristics and no signs of deafferentation. Pain was described as deep and diffuse. It poorly responded to all types of analgesics including oral morphine and transcutaneous fentanyl.

 

The area of pain was confined to a segment from T7 to T10 from the mid-line to the posterior axillary line. Sensory testing demonstrated decreased sensitivity for cold whereas tactile stimulation was felt normally. The skin temperature in the area of pain was 28 degrees C, 5 degrees lower than in the surrounding area and in the corresponding territory on the right side

The patient presented profuse sweating in the area of pain as observed on his shirt while undressing.

The findings were compatible with a complex regional pain syndrome (CRPS). A diagnostic sympathetic block with bupivacaine 0.5% at the level of T7 on the left side equilibrated skin temperature, removed the excessive sweating and made the patient completely pain-free for 7 hours.

On the following day, the patient underwent a chemical sympathectomy with 6% fenol in water. This removed all his pain and he remains pain-free on the first follow-up after two weeks.

CT guided injections for spinal pain - a warning

There is an increasing number of patients being treated for spinal pain by radiologists on the request by general practitioners. Most commonly, these procedures are performed under CT guidance. Besides unnecessarily increasing costs, the use of CT may give a false sense of security. Here are the most common reasons:

1. It is rare that the injection needle can be placed perfectly parallel to the X-ray beams. Therefore, the precise position of the needle tip can rarely be identified. The claimed high precision of CT guided spinal procedures is thus a myth.

This patient has undergone a CT guided "epidural injection" of cortisone for radicular pain from the right L5 nerve root. The underlying cause was a disco-radicular conflict at the level of the L4/5 disc. The radiologist has introduced the needle at the L4/5 level (upper panel). The wrong nerve root (L4) was thus targeted. Injection of contrast shows that there is no spread to the nerve root at the site of conflict in the anterior epidural space (lower panel). Not surprisingly, there was no therapeutic effect of the intervention. 

2. For most spinal pain procedures, contrast should be injected to verify that the taget is reached and that the injection is not made into other compartments like blood vessels. This requires real-time acquisition of the spread of contrast, e.g. that contrast is injected during the exposure. With CT guided injections this is not the case; contrast is injected, the radiologist leaves the room and the exposure is made. In case of an intra-vascular injection, the contrast has disappeared when the exposure is made.

Injection of contrast around the L5 nerve root on the left side also documents a simultaneous appearane of contrast into blood vessels in the spinal canal. This would have gone by undetected if a CT guided injection had been made in stead of real-time imaging with fluoroscopy.

3. The injected contrast will only be visualized in the slices that are chosen for documentation of the procedure, and that are usually perpendicular to the spine. If contrast is injected into a blood vessel and spreads caudally or cranially from the site of injection it will not be observed even on retrospective analysis of the films. This is particularly dangerous in the cervical spine where several severe neurological complications following intravascular injections performed under CT guidance have been reported in the scientific literature. 

4. The indication for the the chosen procedure has not been validated by anybody with appropriate competence to manage patients with spinal pain. The combination of medical history, clinical examination and radiological findings has a diagnostic precision that rarely exceeds 50% to explain the cause of spinal pain. As an example, it is common to find that the CT-guided injections have been made at the inappropriate spinal level or have completely missed the target (see case report above).

5. Doing procedures on demand without in-depth knowledge of the patient's history and clinical examination is unacceptable and inevitably leads to bad results, a majority of which are unknown to the doctor who has performed the procedure. Patients with spinal pain conditions often have complex pathologies that require input from several specialists before deciding which minimal invasive diagnostic and therapeutic procedures should be undertaken.

Not all pain is in the head, contd.

 

The C1/2 joint seen from the side. The upper needle is in the joint and the lower one in the cyst.

The C1/2 joint seen from behind with the needle in the joint. The cyst is just to the right of the joint space

Not all pain is in the head

Our first case concerns an 86 y old woman in good general health who suffers from severe high neck pain and head ache, all on the right side. The symptoms are present since one year and she cannot turn her head right or left without marked exacerbation of her pain. An MRI shows arthritic changes of the interverterbal cervical joints from C1/2 to C6/7 on both sides and a small synnovial cyst in the external part of the right C1/2 joint.

Head ache is a common manifestation of pathology in the three uppermost cervical joints (C0/1, C1/2 and C2/3) caused by trauma or degeneration touching these joints. The head ache is often situated around the eye and is explained by convergence between the trigeminal nucleus and the nerve supply to these joint levels in the upper spinal cord.

 

The relationship between pain and joint pathology is usually established by injections of small volumes of a potent local anesthetic on the nerves that supply these joints or, for the two uppermost joints, by injection of the local anesthetic directly into the joint.

 

Before being referred to our pain centre, the patient had been tested in another institution excluding the C2/3 joint on the right side as the source of pain.

Our working hypothesis was that the patient's pain was caused by the arthritis in the C1/2 joint and/or by the cyst at the same level.

A thin needle was placed under fluoroscopic guidance into the right C1/2 joint from behind and x-ray contrast injected. This injection produced increase in the patient's usual pain at the same time as the cyst filled up with contrast. This lead us to puncture the cyst via a second needle. A communication of fluid between the joint and the cyst was established by injecting into the joint needle and aspirating the same fluid via the cyst needle. Each time the cyst was emptied, the pain completely disappeared. Finally the cyst was drained and a small dose of cortisone injected via the joint needle in order to reduce the inflammation that was the probable cause of the cyst formation.

The patient left the pain clinic one hour after the intervention without any pain and on follow-up one month later she was completely free of pain in the neck and head.