Not All Pelvic Pain Travels the Same Pathway
Superior hypogastric, inferior hypogastric, ganglion impar, and pudendal nerve blocks in endometriosis and chronic pelvic pain — and how pain location can help determine which one to consider.
Different pelvic pain blocks target different neural pathways. The superior hypogastric plexus block is most relevant to deep visceral pelvic pain; the inferior hypogastric plexus block targets a lower pelvic autonomic network; the ganglion impar block is used for selected coccygeal and perineal pain; and the pudendal nerve block is used when the phenotype suggests pudendal neuralgia — classically burning genital or perineal pain aggravated by sitting.
These procedures do not remove endometriosis. In selected patients, they may provide relief and help identify which pathway is carrying a component of pain.
Why Persistent Pain Needs Evaluation Beyond Recurrence
Endometriosis can be an important generator of pelvic pain, and persistent symptoms still require evaluation for residual or recurrent disease. But pain after surgery is not synonymous with recurrent endometriosis.
A patient may also have adenomyosis, pelvic floor dysfunction, bladder or bowel pain, adhesions, peripheral nerve pathology, spinal or musculoskeletal disease, visceral hypersensitivity, peripheral sensitization, or central sensitization — and more than one can coexist.
Surgery treats disease. A diagnostic nerve or plexus block interrogates a pain pathway.
The Four Targets at a Glance
These are clinical phenotypes, not rigid organ-to-nerve maps — pelvic innervation overlaps.
Superior Hypogastric
Deep central visceral pelvic pain
Cramping, pressure, dysmenorrhea.
Key clue: Poorly localized, deep and central.
Inferior Hypogastric
Lower pelvic visceral pain
Deep bladder, vaginal, cervical or rectal-region pain.
Key clue: Lower pelvis, visceral quality.
Ganglion Impar
Coccygeal / perineal pain
Tailbone, anus, distal rectum, perineum.
Key clue: Centered on the tailbone.
Pudendal Nerve
Genital / perineal neuropathic pain
Burning, electric pain, often worse sitting.
Key clue: Burning, positional, sitting-triggered.
Four Pathways Along the Neuraxis
Each target sits at a different level, from the retroperitoneal plexus near the lumbar spine down to the perineal periphery. Position — not the organ alone — is what a phenotype-based work-up follows.
- Superior hypogastric plexus: Deep, central, visceral pain; near the L5 / sacral promontory region.
- Inferior hypogastric plexus: Lower pelvic viscera and mid-pelvic pain.
- Ganglion impar: Coccyx and distal rectum; near the sacrococcygeal junction.
- Pudendal nerve: Genital and perineal burning pain; peripheral and somatic.
1. Superior Hypogastric Plexus Block
Deep visceral pelvic pain
The superior hypogastric plexus is a retroperitoneal autonomic network near the lower lumbar spine and sacral promontory. It participates in visceral nociceptive transmission from pelvic organs. SHPB is therefore most compelling when pain is deep, central, cramping, pressure-like, or otherwise visceral.
- Deep central pelvic aching or pressure
- Severe dysmenorrhea or cramping
- Poorly localized internal pelvic pain
- Persistent visceral-type pain after treatment of visible pelvic pathology
What Does the Endometriosis Evidence Show?
A prospective open-label pilot study evaluated SHPB in 16 patients with refractory endometriosis-associated chronic pelvic pain. Chronic pelvic pain, dysmenorrhea, dyspareunia, and quality-of-life scores improved, with benefit reported through 24 weeks and no serious adverse effects. The study was small, open-label, and not randomized, so the evidence is encouraging but preliminary.
A 2021 review reported long-lasting relief in roughly 50–70% of chronic pelvic pain patients across the reviewed SHPB literature, while emphasizing that evidence is limited and randomized trials are needed. This is not an endometriosis-specific success rate.
Promising does not mean proven. Patient selection and pain phenotype matter.
2. Inferior Hypogastric Plexus Block
Lower pelvic visceral pain
The inferior hypogastric plexus, or pelvic plexus, lies lower in the pelvis and contains sympathetic, parasympathetic, and visceral afferent contributions. It may be considered for selected lower pelvic visceral pain, including deep bladder-, vaginal-, cervical-, or rectal-region pain. Evidence remains limited.
Avoid simplistic rules such as “uterus = superior” and “bladder = inferior.” Pelvic autonomic innervation is overlapping and complex.
3. Ganglion Impar Block
Coccyx, distal rectum and perineum
The ganglion impar is the terminal convergence of the sympathetic chains near the sacrococcygeal region. It is an interventional target for selected pelvic and perineal pain.
- Coccydynia or tailbone-centered pain
- Perineal pain
- Anal or distal rectal-region pain
A 2026 systematic review and meta-analysis found pain improvement after non-neurodestructive ganglion impar blocks for refractory coccydynia, but rated the certainty of evidence as very low.
4. Pudendal Nerve Block
Burning + perineum + sitting
The pudendal nerve is a somatic peripheral nerve. Pudendal neuralgia often presents as genital or perineal burning, electric, or shooting pain that is aggravated by sitting.
The Nantes Criteria
- Pain in pudendal nerve territory
- Pain predominantly worsened by sitting
- Pain does not typically awaken the patient at night
- No objective sensory loss
- Relief with a diagnostic pudendal nerve block
Pelvic Pain Phenotyping Algorithm
Let Pain Location Do the Sorting
Why a Diagnostic Block Can Be So Informative
A Block as a Diagnostic Experiment
A carefully selected local-anesthetic block can function as a diagnostic experiment. If the patient’s familiar pain falls substantially during the expected anesthetic window while another component remains unchanged, that response supports the conclusion that the targeted pathway is carrying an important component of pain.
It does not identify the original disease or prove that residual endometriosis is absent.
Deep central pain 8/10 plus perineal burning 6/10 → after SHPB, deep pain drops to 1/10 while perineal burning remains 6/10. That pattern suggests two pain components, and potentially two different pathways.
Block Is Not the Same as Neurolysis
A temporary diagnostic or therapeutic block should be distinguished from neurolytic procedures designed to intentionally disrupt neural transmission. Neurolysis has an established history in malignant pelvic pain.
For benign chronic pelvic pain, indications, expected duration, autonomic consequences, and alternatives require careful specialist consideration.
Frequently Asked Questions
Can SHPB help endometriosis pain?
Possibly in selected patients with a strong visceral pain phenotype. Endometriosis-specific evidence is encouraging but comes from small studies.
Does a successful block mean endometriosis is gone?
No. A block changes pain transmission; it does not remove endometriosis.
How is a pudendal block different?
It targets a somatic peripheral nerve, while hypogastric plexus blocks target autonomic and visceral pathways.
Should a block replace evaluation for recurrent endometriosis?
No. Persistent symptoms still require appropriate evaluation for structural disease.
Can more than one pain pathway be active?
Yes. Multiple pain generators and pathways can coexist in the same patient.
Pain Location Is Information
If the phenotype doesn’t fit, don’t force the diagnosis — look for another generator or pathway. The goal is not simply to identify endometriosis; it’s to understand why a patient hurts. Once anatomy has been treated, persistent pain deserves another investigation, not another assumption.
Selected References
- Khodaverdi S et al. J Obstet Gynaecol. 2021;41(6):966–971. PMID 33243036. DOI 10.1080/01443615.2020.1820468.
- Urits I et al. Curr Pain Headache Rep. 2021;25(3):13. PMID 33630172. DOI 10.1007/s11916-020-00933-0.
- Urits I et al. Anesth Pain Med. 2021;11:e112225. PMID 34221944. DOI 10.5812/aapm.112225.
- Labat JJ et al. Neurourol Urodyn. 2008;27(4):306–310. PMID 17828787. DOI 10.1002/nau.20505.
- Scott-Warren JT et al. Curr Pain Headache Rep. 2013;17(1):306. PMID 23250792. DOI 10.1007/s11916-012-0306-7.
- Jevotovsky DS et al. Reg Anesth Pain Med. 2026. PMID 40081927. DOI 10.1136/rapm-2024-106055.
This article is educational and does not establish that a particular block is appropriate for an individual patient. Interventional procedures require individualized assessment by an appropriately trained clinician.
