Adjunctive Efficacy of Superior Hypogastric Plexus Block in Chronic Pelvic Pain: A Comprehensive Review.

Chronic pelvic pain (CPP) is a common and complex clinical condition characterized by persistent or recurrent pain in the pelvic region, typically lasting six months or longer. This multifaceted condition significantly impacts the physical and emotional well-being of affected individuals, diminishing their quality of life.[ 1 ] CPP is more frequently reported in women, with prevalence estimates ranging from 4% to 25% among women of reproductive age. Men are also affected, though they report it less frequently.[ 2 ] The condition burdens individuals and healthcare systems considerably due to the high frequency of medical consultations, diagnostic procedures, and the need for various therapeutic interventions.[ 3 ] The etiology of CPP is often multifactorial, involving gynecological, urological, gastrointestinal, musculoskeletal, and neurological factors. Common conditions associated with CPP include endometriosis, interstitial cystitis, irritable bowel syndrome, and pelvic inflammatory disease. The pathophysiology of CPP is complex and not fully understood, often involving an interplay of peripheral and central pain pathways, autonomic dysfunction, and psychological factors.[ 4 ] Chronic inflammation, neuropathic mechanisms, and central sensitization are key contributors to the persistent and debilitating nature of the pain. This complexity complicates diagnosis and management, necessitating a multidisciplinary approach to address the diverse aspects of the condition.[ 5 ] Despite the array of treatment options, managing CPP remains challenging. Many patients experience inadequate pain relief, recurrence of symptoms, or side effects from medications.[ 6 ] The heterogeneous nature of CPP, with overlapping etiologies and comorbidities, often necessitates a trial-and-error approach to find effective treatments. Additionally, the psychological impact of chronic pain, including anxiety, depression, and diminished quality of life, is often insufficiently addressed by conventional therapies. This underscores the need for more comprehensive management strategies that extend beyond traditional methods and incorporate targeted interventional techniques.[ 6 ] The superior hypogastric plexus block (SHPB) is a promising interventional technique for managing CPP, particularly in cases where visceral pain is predominant.[ 7 ] The superior hypogastric plexus, located anterior to the L5-S1 vertebral bodies, transmits pain signals from the pelvic viscera, including the uterus, bladder, and rectum, to the central nervous system. This anatomical location makes it an ideal target for interventional pain management in CPP. The rationale behind SHPB is its ability to interrupt nociceptive signal transmission from the pelvic organs to the brain, thereby providing substantial pain relief.[ 7 ] SHPB works by blocking the sympathetic nerve fibers that carry pain signals from the pelvic organs. By administering a local anesthetic or neurolytic agent to the plexus, SHPB can significantly reduce or eliminate these pain signals.[ 8 ] In addition to pain relief, SHPB can help alleviate associated symptoms such as dysmenorrhea, dyspareunia, and dysuria, which are common in patients with CPP. The procedure is minimally invasive and can be performed under fluoroscopic, CT, or ultrasound guidance, with relatively low risk, making it a viable option for patients who have not responded to conventional therapies.[ 8 ] The hypothesis supporting the use of SHPB as an adjunctive therapy in CPP management is that, when combined with standard care, it can enhance pain relief, improve quality of life, and reduce reliance on long-term opioid use.[ 9 ] By targeting specific pain pathways involved in CPP, SHPB offers a more tailored approach to pain management, addressing some of the limitations of conventional treatments. Future research is needed to validate this hypothesis and establish optimal patient selection criteria, techniques, and long-term outcomes associated with SHPB in managing CPP.[ 9 ] The SHPB is a valuable interventional procedure primarily indicated for the management of CPP associated with various conditions.[ 10 ] The indications and techniques for SHPBare summarized in Table 1 . Indications and techniques for superior hypogastric plexus block (SHPB) Clinical trials and case studies have demonstrated the efficacy of the SHPB as a standalone treatment for CPP.[ 19 ] For instance, a retrospective analysis involving 40 patients revealed that SHPB, using a combination of local anesthetic and steroid, resulted in significant pain relief, with notable reductions in visual analog scale (VAS) scores observed at 1, 3, and 6 months post-procedure.[ 20 ] Additionally, another study highlighted the success of neurolytic SHPB in managing pain among 19 patients suffering from cancer-related pelvic pain, achieving effective pain control throughout a 1-year follow-up period. These findings underscore SHPB’s potential as an effective monotherapy for the management of CPP.[ 21 ] The role of SHPB as an adjunctive therapy has also been explored in various studies. A randomized, double-blind study demonstrated that preemptive ultrasound-guided SHPB significantly reduced postoperative opioid consumption and VAS scores in patients undergoing pelvic cancer surgeries compared to a placebo group.[ 22 ] This indicates that SHPB not only enhances the effectiveness of multimodal pain management strategies but also contributes to reducing reliance on opioid medications and addressing concerns related to opioid dependency. Combining SHPB with pharmacological and nonpharmacological therapies improves overall treatment outcomes for patients suffering from CPP.[ 22 ] The duration of pain relief following SHPB varies across studies, with many reporting sustained benefits. One review indicated that approximately 50%–70% of patients experienced long-lasting relief after the procedure. In the previously mentioned retrospective analysis, patients maintained significantly lower pain scores than their baseline levels at the 6-month mark following SHPB.[ 23 ] However, the literature is less clear regarding the indications and outcomes for repeat interventions. Further research is needed to establish optimal timing and criteria for repeat SHPB procedures to ensure patients receive the most effective and tailored pain management solutions.[ 23 ] The SHPB is a valuable interventional technique for managing CPP; however, it is crucial to compare its efficacy and safety with other nerve blocks and minimally invasive surgical options to identify the most appropriate approach for individual patients.[ 24 ] When comparing SHPB with the ganglion impar block, both techniques are effective in reducing pain, particularly in conditions such as CPP and cancer-related pain. The ganglion impar block is less invasive and can be performed under ultrasound guidance, enhancing patient comfort and safety.[ 25 ] Nevertheless, its efficacy may be limited for visceral pelvic pain, as it primarily targets somatic pain. Similarly, the sacral nerve block has shown effectiveness in managing pelvic pain by interrupting signals from the sacral plexus. While it can provide rapid analgesia with fewer complications when performed correctly, it may not address all sources of pelvic pain, especially those arising from visceral structures, which restricts its effectiveness compared to SHPB.[ 25 ] In terms of minimally invasive surgical options, laparoscopic interventions directly target the underlying causes of CPP, such as endometriosis or adhesions, often resulting in significant pain relief and improved quality of life. Although these procedures are generally safe, they carry risks such as bleeding and infection and potentially high costs associated with operating room fees and recovery times.[ 26 ] Conversely, neuroablation techniques, including radiofrequency and chemical neurolysis, offer long-lasting pain relief similar to SHPB by targeting specific nerves. While these techniques are generally safe, complications such as nerve damage or infection can occur, so careful patient selection is essential. Neuroablation may be more cost-effective than surgical options as these procedures often require less recovery time and fewer resources post-procedure.[ 26 ] A comparative analysis of the SHPB and other interventional techniques for CPP is summarized. The effectiveness of the SHPB in managing CPP is significantly influenced by careful patient selection and an understanding of various predictive factors. To determine candidacy for SHPB, clinicians must consider specific clinical and diagnostic criteria.[ 21 ] Suitable candidates typically include individuals aged 18 to 70 with a confirmed diagnosis of CPP resulting from conditions such as endometriosis or pelvic inflammatory disease. It is crucial to exclude patients with coagulopathy, local infections at the injection site, or those who refuse the procedure, as these factors could complicate treatment and outcomes.[ 21 ] Predictive factors for positive outcomes following SHPB include demographic characteristics, pain intensity, and psychological health. Younger patients, particularly women, tend to respond better to the intervention.[ 27 ] Additionally, individuals with shorter durations of pain and lower baseline pain intensity—assessed using visual analog scales—are more likely to experience significant relief. Psychological factors also play a critical role; patients with lower levels of anxiety and depression often report more favorable responses to treatment, underscoring the importance of mental health in pain management.[ 27 ] A personalized approach is essential to optimize the effectiveness of SHPB in managing CPP. This entails conducting a comprehensive evaluation that includes a detailed medical history, psychological assessment, and physical examination tailored to each patient’s unique circumstances.

In conclusion, CPP remains a challenging condition to manage due to its multifactorial etiology and complex pathophysiology. While current treatment modalities, such as pharmacological interventions, physical therapy, and psychological support, provide relief for some patients, many continue to suffer from inadequate pain control and diminished quality of life. The SHPB emerges as a promising adjunctive therapy, offering targeted pain relief by interrupting the transmission of nociceptive signals from the pelvic organs. There are no conflicts of interest.