|Year : 2017 | Volume
| Issue : 3 | Page : 143-145
Diagnostic pain procedures in managing chronic pain: Relevance in today's time!
Kailash Kothari1, Khushali Tilvawala2
1 Department of Pain management, Pain Clinic Of Pvt. Ltd; Department of Anesthesia and Pain management – King Edward Memorial (KEM) Hospital, Mumbai, Maharashtra, India
2 Fellow of Pain Medicine, Pain Clinic of , Mumbai, Maharashtra, India
|Date of Web Publication||18-Jan-2018|
2005/A, Cosmic Heights, Bhakti Park, Wadala East, Mumbai - 400 037
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Kothari K, Tilvawala K. Diagnostic pain procedures in managing chronic pain: Relevance in today's time!. Indian J Pain 2017;31:143-5
A correct diagnosis is three-fourths the remedy
Pain is subjective in nature. Every patient describes it differently. Chronic pain is a huge burden on the society. Early diagnosis is important in preventing chronic pain. The role of diagnostic pain procedures is considered very important, especially in spine. In conditions where diagnosis is in question or where treatment is not working as expected, the role of diagnostic nerve block comes into play, for example, in cases of chronic low back pain (CLBP), failed back surgery syndrome (FBSS), discogenic pain, neuropathic pain, sacroiliac (SI) joint pain, myofascial pain syndrome, atypical facial pain, and chronic headaches resistant to treatment.
The spine is very dynamic and complex structure. It has to provide stability as well as flexibility to the body. There are many forces including muscles and ligaments acting against each other at the same time. Overlapping symptom is extremely common. In most cases, clinical and radiological correlation provides a definitive diagnosis. But in some cases, even clinical and radiological features do not provide a reliable diagnosis. Apart from specific causes of pain and clear radicular involvement with obvious neurological deficits and corresponding findings of a prolapsed disc in magnetic resonance imaging (MRI) or computed tomography images, a diagnosis of the anatomical cause of the pain can only be established if invasive tests are used.
It is seen in clinical practice that there are many patients with chronic pain suffering for years, suffering just because a right diagnosis is not made in time. When a right diagnostic test is used to identify the pain generator, pain can be controlled in some cases and can be treated in most cases. These patients ask the questions – “Why I was not referred for this treatment earlier?” and “Why I suffered so much for years when this treatment could cure me?” This is very tricky situation for pain physicians to explain the patients that why other specialists failed to provide this remedy.
Cervicogenic headache is another condition where diagnostic blocks help in diagnosis and treatment. Many physicians treat these patients wrongly as migraine. Patients have minimal relief with migraine medicines. Diagnostic nerve blocks using local anesthetic will confirm the diagnosis of Cervicogenic headache. We may perform greater occipital nerve block, cervical medial branches block. (3rd occipital nerve, C3 and C4 medial branches) block will confirm the diagnosis. Radiofrequency (RF) ablation can provide long duration of pain relief. The role of trigger point is also very important in causing pain. It may produce pain similar to compressive cervical/lumbar radiculopathy. Diagnostic trigger point injection can differentiate if pain is originating from the muscle or the nerve.
Provocative discography is another diagnostic test, which is more controversial due to side effects such as discitis and early degeneration of the test disc. Provocative discography is indicated only when the diagnosis is not certain. There should be a clear imaging finding on MRI, which should prompt the investigator to go for the test. Postdiscography, there should be a definitive plan to treat the test disc. With these possible adverse side effects in mind, the risk–benefit ratio should be explained to the patients and informed decision should be taken.
Facet joint pain is very common but under diagnosed condition. It's a clinical diagnosis and a diagnostic local anesthetic block can confirm the diagnosis. RF ablation of the medial branches of dorsal ramus supplying affected facet joints may provide long duration of pain relief.
The incidence of persistent pain in post spine surgery (Failed back surgery syndrome – FBSS) ranges from 10-40% (Average 20%)., It is alarming that in spite of that, we have not changed the way the patients are treated. Willems performed a survey of spine surgeons in the Netherland on value of prognostic tests for improving results of fusion surgery. There is lot of confusion among surgeons in the selection of right patient for lumbar fusion surgery for a very common indication, i.e. CLBP. The three most commonly used prognostic tests in daily practice used in questionnaire were immobilization in a lumbosacral orthosis, provocative discography, and trial immobilization by temporary external transpedicular fixation. The surgeons were asked about their opinion on these prognostic tests for good outcome in fusion surgery. There was considerable lack of uniformity in their opinion about the use and appreciation of these tests. Most surgeons do not use prognostic factors mentioned in literature for decision-making. The patients are exposed to spine surgery without any surety of the outcome. The article also emphasizes that conservative care including psychological treatment (cognitive behavior therapy) has better long-term outcome.
FBSS is a huge burden for patient's family as well society. “FBSS is an artificial construct and not a disease entity in itself. The name implies that patients are distinct from other patients with neuropathic back and leg pain simply because they have been treated by a surgeon. These patients have remained hidden from epidemiological scrutiny; they are prisoners of a surgical algorithm of care. A variety of disciplines, each with its own treatment concepts, have inherited these patients. These include neurological and orthopedic spinal surgery, physiotherapy, pain medicine, rheumatology, neurology, primary care and psychiatry. Surprisingly little communication among them takes place.”
The diagnosis and treatment is delayed, as surgeons believe that further surgery will solve the problem, and pain physicians try various drugs and nondrug interventions in search for the solution. The general practitioners keep referring patients to different specialists desperately., These difficult patients need complex multidisciplinary approach. Diagnostic blocks in these complex patients may identify many treatable conditions. Diagnostic blocks may identify less common structures as pain generators such as psoas and quadratus lumborum muscles, piriformis muscle, gluteus muscles apart from more common pain generators such as disc, facet joints, and SI joints. In a survey performed by Tharmanathan et al. on management of FBSS, the majority of physicians (82%) used various diagnostic techniques to identify pain generator. Most commonly involved diagnostic tests were – Clinical re-evaluation (71%), repeat imaging modalities (65%). These methods were used together in 68% of the responding centers. Diagnostic medial branch block followed by RF ablation was used in 57% of patients. Epidural injection was used in 66% of patients. Thirty-nine percent of patients were implanted with spinal cord stimulation after a successful trial.
Unfortunately, in India, still surgeon–pain physician coordination is very poor. We need to develop a more interactive and responsive multidisciplinary approach for managing such complex patients.
Similarly, in patients with atypical facial pain, diagnostic blocks help in identifying pain pathways – sympathetic ganglions (sphenopalatine and stellate), trigeminal or peripheral nerves such as supra- and infraorbital nerves are few of the nerve blocks pain physicians perform. Using RF or chemical neurolysis, long-term pain relief may be obtained. In patients with neuropathic pain, complex regional pain syndrome (CRPS) I and II, CRPS-not otherwise specified, and vascular ischemic pains, role of sympathetic block cannot be denied. Sympathetic block can distinguish between sympathetically mediated pain and sympathetic independent pain.
Using test dose of intrathecal morphine (for cancer pain) or baclofen (spasticity) is another example of using diagnostic procedure to determine effectiveness and calculating the drugs doses in intrathecal pump for long-term use. While the data for pain relief, adverse effect reduction, and cost-effectiveness with cancer pain control are compelling, the evidence is less clear for noncancer pain, other than spasticity. Trial of spinal cord stimulator (SCS) is also used to confirm patient's response to the electric stimulation on pain before permanent SCS implantation.,
The value of these diagnostic tests cannot be denied. As stated before, due to lack of interdisciplinary communication and understanding, these tests are not well utilized.
We need to answer these questions before performing diagnostic block:
- What we achieve by performing a particular diagnostic test?
- Is there any better test to confirm the diagnosis, which is less invasive or noninvasive?
- What is the further plan of treatment, if test is positive or negative?
If any answer to the above questions is negative, the test should not be performed. If the answer is affirmative, the patient will benefit from the result.
In conclusion, diagnostic tests are very important part of pain management. There is lack of awareness among other specialties about these investigations. Interdisciplinary management of complex pain situation is the need of the hour. Our role as a pain management community is to incorporate these diagnostic tests at proper place in the protocol ladder of the specific pain condition. This will help physicians, patients, and in turn society as a whole, by reducing misdiagnosis and in many nondiagnosis. This ultimately will lead to better quality of life and comfort for the patients.
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