Category Archives: Pain Management

What Is A Good Outcome In Pain Management?

One of the challenges of working as a clinician with people in pain is measuring outcomes.

Pain is an experience, and as a result, it cannot be directly measured.

Instead, we use surrogate measures like a VAS, McGill Pain Questionairre and functional assessments to make an assessment of the severity of someone’s complaint.

Often, improving these surrogates become the focus of the treatment, as they are measurable.

From BPS to Enactive

Earlier this year, Peter Stillwell and Katherine Harman wrote an interesting paper titled An enactive approach to pain: beyond the biopsychosocial model, which looked at the issue of compartmentalisation of pain, even with the biopsychosocial model.

They wrote:

With enactivism at the core of this approach, pain does not reside in a mysterious immaterial mind, nor is it an entity to be found in the blood, brain, or other bodily tissues. Instead, pain is a relational and emergent process of sense-making through a lived body that is inseparable from the world that we shape and that shapes us.

When you conceptualise pain this way, it makes it hard to reduce to a questionaire or numerical score, doesn’t it?

Intensity Is Not Proportional To Suffering

One of the big issues with reducing pain down to a score is that it doesn’t capture the human suffering involved.

This is demonstrated in a 2013 paper from Swedish researchers. The authors wrote:

Common symptoms in patients with chronic pain (such as pain intensity, depression, and anxiety) showed great variability across subjects.

That’s not to discount the importance of gauging pain intensity, as the same paper found:

With respect to the investigated aspects of participation and health, pain intensity showed stronger multivariate relationships than psychological symptoms.

Which potentially suggests that for a majority of people, their pain is the primary issue which manifests as psychological symptoms.

However, another paper showed that people with depression experienced nociceptive pain differently (more intensely) compared to healthy controls:

The present study stresses that the initial evaluation of pain intensity among depressed patients is increased compared with HC. This negative bias might affect the way pain is experienced by depressed patients and serve as a mediator between depression and pain complaints. 

There is also evidence that factors like controllability can positively influence suffering without changing pain intensity:

control over pain primarily reduces the degree of perceived suffering. This effect was modulated by the subjects’ locus of control: The more participants attributed their behavior to chance, the greater was the reduction of suffering when they had control over their pain. Pain intensity and unpleasantness ratings, by contrast, were unaffected by control over pain.

Though caution must be used when applying this research to practice, as it was experimentally induced pain.

As you can appreciate, even with a small sampling of literature, pain is very “messy”, and difficult to quantify and separate into contributing and effected factors.

Proportion of Patients Making Clinically Significant Improvement

Despite this messiness, something needs to be measured.

Why?

To try and gauge both clinical and economic effectiveness and efficiency of pain management programs and interventions.

Enter the proportion of patients making a clinically significant improvement number.

This is used to gauge how many patients at a particular clinic or hospital improve by at least the minimum clinically significant amount.

Example: the Brief Pain Inventory

A common measure of pain, the Brief Pain Inventory has two aspects – pain intensity looks at worst, best and average pain, where it is felt and the pain interference part looks the impact of this pain on aspects of life.

The minimum clinically significant improvement for this is 10%, and the benchmark for pain clinics is to achieve at least this reduction (in average pain) in at least 30% of patients.

Real World Outcomes Differ To Social Media Outcomes

Given the complex, multi-factorial nature of pain, and the inherent challenges in measuring outcomes, results in real world chronic pain clinics are definitely not eye catching, however they can be life changing.

The above image shows outcomes from clinics who participate in the electronic Persistent Pain Outcomes Collaboration (ePPOC). When you look at the “all services” column, it paints a picture of how difficult it is to make clinically significant improvements in each area, with only about a quarter of clinics able to improve average pain rating.

When No Progress Is Progress

Sometimes, we have to accept that the best we can do is stop things from getting much worse.

If you can keep someone’s pain intensity relatively stable, help prevent them catostrophising and falling into depression, then it might not show up as a positive outcome by the numbers, but in reality, it is a HUGE WIN.

Be Optimistic, But Realistic

Instead of delivering false hope for people with advertising and what is said in practice, one of the best things you can do for persistent pain patients is be realistic, in an optimistic way.

That is, explain the facts of their situation, and what is factually known to help and hinder this, but spin it in a way that is positive, and builds confidence in you and potentially themselves that this is the right path for them.

Overall, know that any victories in chronic pain management are hard won, and that it is important for your own health as a practitioner to recognise this and acknowledge your efforts and the role you played in someone’s health. Otherwise, it can be a fast path to burnout.

Author

This post was written by Nick Efthimiou, a contributor to Beyond Mechanical Pain.

References

An enactive approach to pain: beyond the biopsychosocial model

Is Pain Intensity Really That Important to Assess in Chronic Pain Patients? A Study Based on the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Initial Evaluation of Pain Intensity Among Depressed Patients as a Possible Mediator Between Depression and Pain Complaints

Impact of controllability on pain and suffering

Patient Outcomes in Pain Management – Enterprise One Pain Management Service

Spinal Cord Stimulation: Neuromodulation for Chronic Pain

Spinal Cord Stimulation (SCS), a form of neuromodulation, can be used to treat certain chronic, intractable pain conditions that have not responded to more conservative approaches such as medication, surgery, manual therapy, exercise or psychological interventions.

Despite being considered minimally invasive, it is not without risk and is considerably expensive.

Having been in use for over 50 years, the technology is evolving at a fast pace, with newer approaches targeting different anatomical structures and using differing forms of stimulation.

However, the overall success rate associated with the use of the technique has not improved over recent times. (1) 

What Does It Involve?

There are several different types of SCS, but generally it involves the placement of specialised electrodes into the epidural space or around the dorsal root ganglion.

It is typical to trial SCS before implantation. This is done via percutaneous leads, connected to an external battery. This allows the patient to experience stimulation, and gauge their response to the therapy.

If the patient responds, then a complete system is implanted, which consists of:

  • Leads/electrodes (either surgical leads, which require a laminotomy to insert, or percutaneous leads, which can be inserted through a needle)
  • Anchors (fastening sleeves to hold the leads in place)
  • Implantable Pulse Generator (IPG)

The electrodes connect to the implantable pulse generator (IPG), which is similar to a cardiac pacemaker in size and shape. This is typically implanted in the lower back or flank, though sometimes it is place in the abdomen.

The system is then programmed to deliver electrical current to the spinal cord or nerves, like a TENS machine. The system is programmed via a wireless connector through the skin, with the information stored on internal memory inside the IPG.

There are both rechargeable and non-rechargeable (primary cell) IPGs on the market, with advantages and drawbacks to both. Charging is done via a wireless charger, similar to a mobile phone charger.

How Does It Work?

The electrodes generate electrical fields between them and the change in charge influences the nervous tissue in the vicinity, causing either depolarisation or hyperpolarisation of neruons.

It is thought to provide pain relief via several mechanisms.

Early stimulation with some reference to Melzack and Wall’s gate control theory via tonic stimulation of the dorsal column. This involved the patient experiencing parasthesia over the pain area, masking their pain.

Newer paradigms involve multiple waveforms and frequences, with different anatomical targets, such as the dorsal horn. These forms of stimulation can be delivered at sub-parathesia thresholds, and still provide pain relief.

Areas of the nervous system known to be affected in successful SCS stimulation include the dorsal columns of the spinal cord, supraspinal regions and higher order processing within regions of the cortex.  Other, more recently reported  effects of SCS have been identified in glial cells and descending modulatory systems.  Despite a great deal of research on the topic, it is fair to say that the exact mechanisms regarding the efficacy of SCS are still fairly hazy.  (2)

What are the indications? 

Its main use of SCS is for intractable pain conditions. 

Because of the invasive and expensive nature of SCS, it is not used unless the indications for it are clear, and even then, typically after all other approaches have been exhausted. 

The patients who are candidates for SCS are often in debilitating pain and experience a great deal of associated suffering and disability.  This is not an approach for your garden variety back pain! 

Neuropathic pain is the most common indication and some of the conditions include: 

  • Failed back surgery syndrome – chronic back pain following any type of invasive lumbar surgery such as laminectomy or fusion surgery.  
  • Chronic Regional Pain Syndrome (CRPS) of a single limb 
  • Chronic migraines
  • Chronic pelvic pain

Other Applications of SCS

There is a growing area of research for the use of SCS with people who have sustained a spinal cord injury in order to restore some motor function. We won’t discuss this beyond mentioning it.

Does it work?  

To answer this question, first we need to define work

When we are talking about the efficacy of treating chronic pain, the parameters generally used to define success are a reduction of pain on a VAS scale by 30-50%.

Understanding expectations are really important in this field as miracle cures and complete pain relief are fairly infrequent.  Whilst most people might consider a 30% reduction in pain to be insufficient, on a more functional level it may mean the difference between a person being able to tolerate being in the car for an hour compared to just 10 minutes, or a reduction or cessation of opioid or other medications which carry with them a whole lot of life interfering side effects of their own.

Tread Carefully With The Evidence

There are few true placebo SCS studies. This means it is hard to know the magnitude of the specific effect of spinal cord stimulation on pain and function.

Because parasthesia based stimulation was the dominant method for the majority of SCS history, it was traditionally hard to conduct a double-blinded trial. Hence, we must interpret the studies with caution.

It’s also important to note that the multifactorial nature of pain means that some people are likely to respond  to SCS better than others. This is likely due to the pain being mediated by other factors not related to the nervous system itself. Factors that are known to reduce the chances of SCS being effective include depression, PTSD,  the presence of third party compensation, misuse of alcohol or other drugs, low self efficacy and other evidence of poor coping skills  (3, 4).    

Without boring you to death with an extensive review of the literature, it would be fair to say that around half of the people implanted with SCS, regardless of the system used, the type of lead placement or the differing use of electrostimulation types (burst, frequencies etc.)  achieve a reduction in their pain of between 30 and 50%.

This reduction in VAS scores goes hand in hand with increases in function and quality of life.   In practice, having a skilled operator is likely to increase the chances of success and reduce complication rates, and some influential clinicians are aiming for 80/80 – an 80% pain reduction in 80% of patients, given the improving technology and optimal patient selection, which is going to give the best success rates for a particular clinic  (1, 4, 5).

More Than Numbers

In the pain clinic setting, the suffering that often goes hand in hand with neuropathic pain can be almost unquantifiable. 

Ordinary people who are unlucky enough to be afflicted with this condition in its variable forms tend to say very similar things about their situation and often follow an understandable downward spiral of loss of function and increasing misery. 

The depression and fear avoidance with movement that frequently accompanies the suffering  are the target of the allied health team working with these patients.  Whilst they are frequently modifiable to a degree, they are also incredibly understandable given the situation. 

The desire to have an option to at least try to ease suffering is the obvious rational for the use of SCS in the pain clinic setting, despite its lack of overwhelming efficacy.  When it goes well, it changes lives.

References

1. Sdrulla AD, Guan Y, Raja SN. Spinal Cord Stimulation: Clinical Efficacy and Potential Mechanisms. Pain Pract 2018;18:1048-67.

2. Vallejo R, Bradley K, Kapural L. Spinal Cord Stimulation in Chronic Pain: Mode of Action. Spine (Phila Pa 1976) 2017;42 Suppl 14:S53-60.

3. Blackburn DR, Romers CC, Copeland LA, Lynch W, Nguyen DD, Zeber JE, Hoffman MR. Presurgical Psychological Assessments as Correlates of Effectiveness of Spinal Cord Stimulation for Chronic Pain Reduction. Neuromodulation 2016;19:422-8.

4. Prabhala T, Kumar V, Gruenthal E, Collison C, Prusik J, Owusu S, et al. Use of a Psychological Evaluation Tool as a Predictor of Spinal Cord Stimulation Outcomes. Neuromodulation 2019;22:194-9.

5. Brinzeu A, Cuny E, Fontaine D, Mertens P, Luyet PP, Van den Abeele C, et al. Spinal cord stimulation for chronic refractory pain: Long-term effectiveness and safety data from a multicentre registry. Eur J Pain 2019;23:1031-44.