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10 Articles in this Series
Introduction
An AAPM 2019 Preview
APRNs/PAs in Pain Medicine SIG Gets Underway
Cannabis Has Entered Pain Management and Is Here to Stay: What Clinicians Need to Consider
Managing Pain in Marginalized Populations, including Ethnic Minorities, LGBTQ, and the Obese
Neuromodulation: A Roundtable on Current Best Practice & Key Questions
Pro/Con: CGRP Antibodies and Treatment Choice for Chronic Migraine
Pro/Con: Conservative Care is the Best Route for Chronic Pelvic Pain
Pro/Con: CRPS - Use Everything but Stimulation
Pro/Con: Ketamine for Complex Regional Pain Syndrome, Neuropathic Pain, and More
Pro/Con: Radiofrequency Denervation is Effective (The MINT Studies)

Pro/Con: Conservative Care is the Best Route for Chronic Pelvic Pain

A Pro-Con Debate* on the following statement, held at the 2019 annual meeting of the American Academy of Pain Medicine (AAPM):  "Conservative Care is the Best Route for Chronic Pelvic Pain."

 

PRO, offered by Jennifer Hah, MD
Both epigenetic and environmental factors may influence chronic pelvic pain (CPP), which can range from endometriosis to urologic or gastrointestinal to musculoskeletal categories, and which includes sexual, behavioral, emotional, and cognitive consequences. There is also a strong correlation between early childhood abuse and adult CPP and visceral pain processing. CPP conditions are often a diagnosis of exclusion, such as for interstitial cystitis. Conservative care may begin with patient education, self-care, behavioral modification, and PT, and lead up to more interventional care including hydrodistention, neuromodulation, and eventually surgery.

In looking at data for conservative approaches for CPP, I prefer to use meta-analyses over individual clinical trials, since pooling research results of several clinical trials improves the power of small or inconclusive studies and allows for identification of sources of diversity across studies. In one review of 13 RCTs involving 750 women, hormonal therapy was shown to be more effective than placebo, resulting in more than a 50% reduction in VAS scores; gabapentin was demonstrated to be more effective than amitriptyline; and reassurance ultrasound scans and counseling led to greater improvements in pain over standard care. Another review looked at 38 studies involving 3,290 men: acupuncture, along with lifestyle modifications and physical activity led to meaningful symptom reduction. Intravesical Botox has also been shown to reduce interstitial cystitis pain across seven RCTs and one retrospective study.

My message is that if we want to treat the patient as a whole, it is important to acknowledge that the chronic stress that occurs in adulthood may be playing into the pathology of CPP, as well as any early childhood events that may have led to epigenetic changes. Ultimately, optimizing conservative management of chronic pelvic pain should always be considered whether or not patients decide to pursue sacral nerve stimulation.

 

CON, offered by Corey W. Hunter, MD:

Sometimes, I think we are just spinning our wheels with patients when we try conservative care approaches and we should be more aggressive. In my view, sacral nerve stimulation (more specifically sacral DRG stimulation) can be better than conservative care for chronic pelvic pain, in the right patient. 

Pelvic pain is typically neuropathic in nature ... consequently, anti-inflammatories are rarely effective. A commonly used class of medications for neuropathic pain is anti-depressants, such as TCAs.  When it comes to pelvic pain, patients typically have documented anxiety and depression; if these patients are being treated with SSRIs or SNRIs, anti-depressants cannot be used due to the risk of serotonin syndrome. While opioids are commonly used for pain, they are considered fourth or fifth line treatment for neuropathic pain, making them less than ideal for pelvic pain. In the end, this leaves gabapentin and anti-epileptics – both are extremely sedative and neither have a good track record for  benefitting pelvic pain.

As Dr. Hah noted, conservative care may involve physical therapy pelvic floor, as well as trigger point injections (TPIs) and chemodenervation (ie, Botox on selected muscles in the pelvic region). While these injections may have varying degrees of efficacy, there are literally dozens of muscles in the region that overlap each other, making it extraordinarily difficult to determine precisely which one(s) are contributing to the pain and which one(s) to select as targets for injection. Furthermore, even if one were able to identify a target muscle(s) for injection, it may prove extremely challenging to reach the precise target given how closely packed together the structures are in the area; in addition, there is a high likelihood that the injectate would overflow into important nerves or nearby structure, which could lead to incontinence or weakness in the patient.  

Chemodenervation is becoming increasingly popular, however, the process primarily supports spasticity, dyschezia, and dyspareunia, not pain.  Ultimately, neither TPIs or chemodenervation have been standardized for the treatment of pelvic pain. As it pertains to basic nerve blocks, there 16 named nerves in the region (8 on each side), each with overlapping innervation making it equally as difficult to choose an effective target. The patient essentially becomes a “piñata" as the clinician tries one nerve after another, hoping to provide some degree of pain relief.  Other targets, such as the ganglion of impar and the superior hypogastric plexus, are certainly more predictable when it comes to what regions they receive innervation from; however, targeting these areas for pain has only been validated in cancer patients to date and may only provide temporary relief at best.

Most patients with pelvic pain initially seek treatment with their gynecologist/urologist or PCP; as a result, their symptoms may likely be chalked up to an infection of some kind rather than something “pain related.” Consequently, these patients tend to receive round after round of antibiotics and undergo unnecessary tests (eg, cystoscopies, pelvic MRIs) before finally ending up in the office of a pain doctor years later.  On average, it may take 3 to 5 years before a patient with chronic pelvic pain (CPP) sees a pain doctor and, by that time, the pain has become centralized and near impossible to treat with conservative therapy.

It has been suggested that CPP may actually be a form of CRPS as it presents with all of the relevant symptoms but in the pelvic region as opposed to an arm or foot. Since one cannot visually see the hallmark sign of CRPS in a patient with CPP, as one would expect to see the foot for example (eg, swollen, blue, cold to the touch) it may be easily dismissed.  However, the similarities are there:

  • Allodynia: In a patient with CRPS of a limb, he/she cannot withstand even the slightest touch to the affected extremity.  In a patient with CPP, sensations as innocuous as urination or taking a bath are equally as excruciating
  • Changes in blood flow: In a patient with CRPS, the classic sign is a swollen, discolored limb due to changes in blood flow stemming from irregular sympathetic innervation to the affected limb. Many patients with CPP have been noted to have extreme regional changes in blood flow which some have been labeled “pelvic congestion syndrome.”
  • Responds to sympathetic blocks: Typically, the first injection a patient with CRPS in an extremity receives is a sympathetic block: stellate for upper extremities and L2 for lower. While the long-term results vary greatly from patient to patient, the vast majority of patients with CRPS may note transient changes in the affected limb with the injection, albeit temporary. Patients with CPP tend to have similar responses to sympathetic blocks for the pelvis (ie, ganglion of impar and superior hypogastric plexus)

Ultimately, patients with late-stage or refractory CRPS tend to opt for spinal cord stimulation. Now, with the advent of DRG stimulation, neuromodulation is far more effective and has move much further up the algorithm of care. If one truly considers CPP as a form of CRPS, then neuromodulation, in particular, DRG stimulation, should be considered much sooner for these patients as well. As stated earlier, many patients with CPP waste 3 to 5 years due to the inability to recognize their symptoms as a pain syndrome. If the medical field recognized CPP as a form of CRPS and treated it with the same sense of urgency, physicians would not let it sit for so many years before taking the appropriate actions and offering pain-related treatments.  Just like CRPS, where clinicians are moving to DRG stimulation within a few months of the onset of pain, we should be offering sacral DRG stimulation with the same speed.

Among the many advantages, DRG stimulation has over traditional SCS, perhaps its most important as it relates to CPP is its ability to provide stimulation to precise areas.  Of all the diagnoses SCS is used for, CPP has the highest rate of explant, with 1in 3 patients declaring the therapy a failure at 1 year. This may be largely due to an inability to sufficiently target the area of need (ie, the sacral fibers) or the inability to capture all of the areas of pain (ie, pelvic innervation ranges from T12 to S4, and unwanted stimulation in unaffected areas).  In the case of DRG stimulation, a clinician can specifically target the sacral fibers simply by placing a lead over the desired sacral level. Additionally, the data from the ACCURATE study shows that DRG stimulation works better when it is programmed at low settings where paresthesias cannot be perceived.  In many cases, the L1 level is targeted as well to provide thorough coverage of the entire pelvic plexus. Since its commercialization in 2016, physicians have found sacral DRG stimulation to be an extremely effective treatment…so much so that many advocate the use of this therapy very early on in the progression of the pain. 

 

Given how successful sacral DRG stimulation has become for CPP by its own right, not to mention how considerably more effective it may be compared to conservative therapies, it should be considered much earlier in the treatment algorithm for these patients…. In most cases, they will only need to have the procedure performed once, with a maintenance procedure every 5 to 7 years.

Editor’s Note: Dr. Hunter explained a small case series he did on this type of stimulation in patients with chronic pelvic pain, which led to no explants and sustained relief at 1 year. Vivianne Tawfik, MD, PhD, who presented a PRO position for conservative care in CRPS weighed in during the Q&A session, noting that she almost exclusively treats CRPS and always strives for optimal treatment. “Sometimes I do refer for DRG stimulation and that does help, but it’s not always enough. It may allow the patient to participate in PT, for instance, but we also use other multimodal approaches in combination. Sometimes, even if conservative care has failed, we have to consider that it was not optimal care.” Ajay B. Antony, MD, who presented on radiofrequency denervation, agreed, adding that he often gets his patients into PT immediately after implant procedures and works with physical therapists to ensure they understand neuromodulation and how it works.

 

*Quotes and comments have been updated/added to since the live event. Commenters’ disclosures may be found on the AAPM35 speakers’ website.

Next summary: Pro/Con: CRPS - Use Everything but Stimulation
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