Spinal Cord Stimulation for Diffuse Visceral Hyperalgesia in the Abdomen: A Case Report and Literature Review Open Access

Abdominal pain is a form of visceral pain, common in some gastrointestinal disorders such as peptic ulcer disease, pancreatitis, Crohn’s disease, and various neoplasms [1]. While visceral and somatic pain differs in the way their afferent neural and sympathetic efferent pathways reach the spinal cord, the two classifications can share nociceptive, neuropathic, and algopathic (e.g., fibromyalgia) qualities [2]. Treatment for abdominal visceral pain is challenging. Often, surgical intervention becomes necessary after first-line pharmacological management fails. Spinal cord stimulation (SCS) has known utility for treating pain disorders, especially neuropathic pain syndromes [3, 4]. While evidence exists that SCS is also effective for visceral pain, this has been limited to pain located in only 1 to 3 abdominal quadrants rather than all 4 [5, 6]. As such, we report a case of SCS for diffuse, abdominal visceral hyperalgesia secondary to chronic pancreatitis and post-pancreaticoduodenectomy (Whipple) procedure. We also provide a review of the literature for similar cases treated via SCS.

A patient in their 70s with a history significant for a pancreatic cyst status post-Whipple procedure in 1991, complicated by chronic pancreatitis and pancreatic insufficiency thereafter, presented to our neurosurgery clinic for permanent SCS placement. At the time of evaluation, the patient had a 30-year history of chronic abdominal pain, progressively involving all four quadrants. After failed pharmacological management including opioids, tricyclic antidepressants, and duloxetine, the patient underwent multiple gastrointestinal interventions such as endoscopic retrograde cholangiopancreatography for pancreatic duct dilatations and general surgeries for lysis of adhesions. The patient also failed multiple pain clinic treatments including celiac plexus blocks, right-sided transversus abdominis plane blocks and trigger point injections, right anterior abdominis nerve radiofrequency pulsing, and right thoracic 9–thoracic 11 (T9–T11) intercostal nerve blocks and trigger point injections. Of note, the muscle and nerve blocks provided initial benefit before habituation prevailed. Given the refractory nature of the patient’s visceral pain, he underwent an SCS trial via the pain clinic. The patient’s visual analog scale (VAS) scores before the SCS trial averaged 8/10. Prior to the SCS trial, he underwent routine psychological evaluation, which revealed that his mobility, sleep, social and sexual functioning, and some recreational/physical activities were diminished because of chronic pain. Preoperative magnetic resonance imaging of the cervical spine showed multilevel cervical spondylosis, worse at cervical 4–cervical 7 (C4–C7) without cord impingement, and magnetic resonance imaging of the thoracic spine was largely unremarkable.

For the SCS trial, two 8-contact SCS percutaneous leads were advanced to the top of T7 since optimal level of stimulation was at the superior aspect of mid-T7. Following the trial, the patient noted a 90% relief of chronic visceral hyperalgesia, with VAS scores decreasing to 1–3/10. Given the positive response to the SCS trial, the patient opted to proceed for permanent SCS placement. We therefore proceeded with a T8 laminotomy and implantation of five 4-contact Penta SCS paddle leads (St. Jude Medical/Abbott, Chicago, IL, USA) at the mid- to superior T7 level with a right flank, Eterna rechargeable pulse generator (St. Jude Medical/Abbott, Chicago, IL, USA) (Fig. 1). The perioperative period was uneventful without any complications. Initial device settings were pulse width of 500 microseconds (inter-burst) and 1,000 microseconds, frequency of 40 Hertz, and current of 1.7 milliamperes. Postoperatively, the patient was able to discontinue opioids but continued the same regimen of duloxetine.

At 1-month follow-up, the patient had at least >90% pain reduction in his habitual painful areas (all four abdominal quadrants). He also reported an improved quality of life, particularly in his mobility and ability to engage in recreational/physical activities. VAS score relating to his chronic abdominal pain was 0/10. No changes to SCS parameters were therefore needed. At 3-month follow-up, despite persistent resolution of his visceral hyperalgesia, the patient began having upper thoracic incisional pain (VAS score = 6/10) consistent with muscle strains and spasms. After undergoing 2 months of physical therapy and methocarbamol, the patient’s incisional pain was under better control (VAS score = 4/10). At 12-month follow-up, the patient continued to report >90% pain relief. SCS settings at this follow-up visit were pulse width of 1,000 microseconds, frequency of 40 Hertz with an intra-burst rate of 500 Hertz, and current of 1.20 milliamperes (step size and maximum of 0.05 and 1.20 milliamperes, respectively).

The prevalence of visceral pain in the global population is estimated as ∼20% [7, 8]. In 2016, there were roughly 25 million emergency department visits and 2.5 million hospitalizations for visceral pain localized to the chest, abdomen, or pelvis – increasing the cost of healthcare in the USA [7, 9]. Although outside the scope of this study, SCS potentially paves the way to impact long-term cost-effectiveness in the treatment of visceral abdominal pain. Our report discusses the treatment paradigm, indication, and response to SCS for chronic visceral pain in the abdomen. Neuromodulation as a therapy for refractory visceral hyperalgesia is not novel, especially when the pain is easily localized to the right upper quadrant or epigastric area [5‒7]. However, the present case offers insights into the success of SCS when visceral pain is complicated and diffusely located in all 4 quadrants of the abdomen.

A review of the literature yielded similar reports discussing the use of SCS for refractory abdominal pain but differed primarily in their indications. Whereas we used SCS for visceral pain with an ambiguous location in all 4 quadrants, the other authors used SCS for abdominal pain with a clearly defined dermatomal pattern. Search criteria across three electronic health databases (PubMed, Ovid MEDLINE, and Ovid Embase) included “spinal cord stimulation,” “SCS,” “abdominal pain,” and “visceral pain” in various combinations with Boolean operators. One of the earliest reports of SCS for abdominal pain was via Khan et al. [5] in 2005. They published a case series of 9 patients, each with distinctly localized visceral pain in a quadrant/side of the abdomen, who were treated with SCS for refractory pain [5]. The etiologies varied from chronic pancreatitis to post-traumatic splenectomy to chronic pain secondary to laparotomies [5]. In the 9 patients, SCS led to an average reduction of 4.9 points in VAS scores and a >50% decrease in opioid use postoperatively [5]. Pain relief persisted at 1-year follow-up. In 2011, Mekhail et al. [4] reported a case series that included a cohort of 29 patients with visceral pain in the chest, abdomen, or pelvis treated with SCS. Unfortunately, the authors grouped these patients together and therefore did not delineate the abdominal locations for pain [4]. Instead, the scope of their paper was to discuss complications associated with SCS for visceral pain, for which they found 1/29 patients (3.4%) acquiring a surgical site infection at an unknown timeline [4]. Kapural et al. [10] also reported a case series of 30 patients treated with SCS for chronic pancreatitis. The authors here also did not report abdominal locations for pain but rather discussed the efficacy of SCS for visceral pain [10]. They found that 24/30 patients (80.0%) had at least >50% pain in relief in habitual painful areas following SCS placement, with VAS scores decreasing from 8/10 to 3.6/10 on average and opioid use reducing from 165 to 105 morphine equivalents per day [10]. Most recently, Mamaril-Davis et al. [6] reported SCS for right upper quadrant pain due to sphincter of Oddi dysfunction, with paddle leads at T6–T7. The patient continued to have >90% pain relief at 18-month follow-up [6].

There were no complications in the early postoperative period. Instead, the patient acquired surgical incision pain in the upper thoracic region 3 months after SCS placement, likely due to muscle spasms. After a trial of methocarbamol and 2 months of physical therapy, the patient’s muscle spasm improved. Complications following SCS are varied according to the literature: lead migration, over/under-stimulation, hardware malfunction, infection, seroma, hematoma formation, allergic reaction, and cerebrospinal fluid leak [11]. Complication rates are more ambiguous, ranging from 2.5 to 43% [11‒14]. Of the complications themselves, lead migration tends to be the most common, with those rates ranging from 2.5 to 22.9% [12‒14]. Risk of lead migration, however, can be diminished by use of paddle leads instead of percutaneous leads (paddle leads were incorporated in the present case). Knife et al. [14] reported a lead migration rate as low as 2.5% in 81 patients receiving paddle leads. Further, Babu et al. [13] described 22.9% of 4,536 patients receiving percutaneous leads and 8.5% of 4,536 patients receiving paddle leads requiring reoperation due to lead migration at more than 5 years.

This study has several limitations. SCS therapy for chronic abdominal pain is not FDA approved and is an off-label therapy. Additionally, as a single case report, this study lacks inherent generalizability, and caution should be exercised when considering any expansion of SCS indications. However, SCS may be considered in cases of visceral pain without a clearly defined dermatomal distribution (e.g., pain diffusely located across all 4 abdominal quadrants). Pain severity was assessed using VAS scores, which are inherently subjective due to their reliance on patient self-report. While VAS remains the current standard for pain assessment, its limitations reduce the objectivity of outcome measurements. Moreover, clinical data from earlier reports often lack granularity, further limiting comparative insights [4, 10]. Although the patient was able to discontinue opioid use following SCS placement, he continued other pain medications, suggesting that SCS may serve as an adjunct rather than a standalone therapy. Further investigation, including randomized controlled trials, is necessary to identify which patients with chronic abdominal pain are most likely to benefit from this intervention. The CARE checklist was utilized (available at https://doi.org/10.1159/000546229).

SCS is a viable treatment option for chronic abdominal visceral hyperalgesia that is refractory to conventional pharmacological and gastrointestinal interventions. However, multidisciplinary involvement and careful patient selection should remain central to the surgical decision-making process.

The Institutional Review Board (IRB) at The University of Arizona College of Medicine – Tucson determined that the study did not require IRB approval. The IRB submission identification number is STUDY00003887. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

The authors have no conflicts of interest to declare.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Conception and design: Mamaril-Davis and Weinand. Acquisition of data, approved the final version of the manuscript on behalf of all authors, and study supervision: Weinand. Analysis and interpretation of data, critically revising the article, and reviewed submitted version of article: Mamaril-Davis, Palsma, and Weinand. Drafting the article and institutional review board submission: Mamaril-Davis.

The data that support the findings of this study are not publicly available due to privacy reasons but are available from the corresponding author upon reasonable request.