If you are reading this, the pattern probably feels familiar. The C-section was years ago. The incision healed. Then the burning started — sometimes weeks after the surgery, sometimes after a second pregnancy, sometimes seemingly out of nowhere. It is felt at one specific spot on the lateral edge of the Pfannenstiel scar, and it radiates into the mons pubis, the labia, or the upper inner thigh. Tight waistbands make it worse. Sitting cross-legged makes it worse. Sometimes intimacy makes it worse. You have been told it is “scar tissue,” “adhesions,” “post-surgical pain,” “endometriosis,” “pelvic floor dysfunction,” or — worst — “stress.” Maybe you have had a laparoscopy that found nothing. Maybe you have been on pelvic-floor physical therapy that hasn’t moved the dial.
This post is about what that pain often is, why it gets misdiagnosed for years, and how a short diagnostic nerve block helps identify the source.
Why this gets missed
There are three reasons chronic Pfannenstiel-incision nerve pain gets misdiagnosed for years.
First, the differential default for chronic lower-abdominal pain in a woman of reproductive age is gynecologic. The first stop after the primary care visit is a gynecologist. The standard workup — pelvic exam, transvaginal ultrasound, laboratory studies, often a diagnostic laparoscopy — is structured to find endometriosis, adenomyosis, ovarian pathology, fibroids, or pelvic adhesive disease. It is not structured to evaluate abdominal-wall neuropathy. A negative pelvic workup typically yields a diagnosis of “chronic pelvic pain of unclear etiology” or a presumed endometriosis without histologic confirmation. The patient ends up on hormonal suppression and physical therapy. Neither addresses a peripheral nerve generator.
Second, the pain mimics conditions that are far more commonly diagnosed. Endometriosis affects roughly 10% of women of reproductive age (Zondervan 2020). Nerve entrapment after a Pfannenstiel incision is less common, reported in about 2% to 4% of patients who have this incision (Loos 2008). Bayesian reasoning makes endometriosis the leading hypothesis by default. The clinical features that point to nerve entrapment — burning quality, positive Tinel sign, no cyclical fluctuation, no menstrual aggravation — are not part of the routine gynecologic exam.
Third, the right diagnostic test is not part of the gynecologic workflow. An ultrasound-guided TAP-plane block at the lateral edge of the Pfannenstiel scar is performed in pain medicine clinics with image-guided procedural infrastructure. It is not usually part of an obstetric or gynecologic practice, so patients who need it may not be referred for it, and the workup can go in circles.
The workflow that addresses this: map the painful skin (the ilioinguinal nerve supplies the inguinal crease and base of the labia, the iliohypogastric a band above the inguinal ligament), test for a Tinel sign along the upper edge of the Pfannenstiel scar, and, when the exam points to one nerve, do an ultrasound-guided block at the Tinel-positive level. The first visit covers the history and exam. The block itself takes about 30 minutes from check-in to walk-out.
The anatomy that matters
The Pfannenstiel incision is a transverse, low, suprapubic incision used for cesarean section, benign hysterectomy, and pelvic reconstructive surgery. It is typically 10–15 cm long, made 2–4 cm above the pubic symphysis, with fascia closed in layers including the rectus sheath. The skin incision is cosmetic. The underlying fascial closure is where the nerves get caught.
The ilioinguinal nerve (L1) and the iliohypogastric nerve (T12–L1) both cross the Pfannenstiel surgical field at the lateral edges of the incision. They run between the internal oblique and transversus abdominis muscles, pierce the internal oblique near the front of the hip bone, and then run toward the midline between the abdominal wall layers, ending a few centimeters from it. Cadaver mapping shows both nerves lie within reach of low transverse incisions (Whiteside 2003). Where a Pfannenstiel incision extends past the outer edge of the rectus muscle, the fascial closure can catch a nerve in suture, and scar around the suture can compress it. That is why the Tinel-positive point usually sits at the outer end of the scar, several centimeters from the midline.
The genitofemoral nerve (L1–L2) is anatomically less commonly involved with Pfannenstiel surgery than with inguinal hernia repair, but it can be irritated by deeper retraction during pelvic dissection — particularly in patients who had concurrent pelvic node dissection or extensive bladder reflection.
One more nerve belongs on the list when the tender spot sits higher on the belly, beside the outer edge of the rectus muscle rather than at the end of the scar: an anterior cutaneous branch of a lower intercostal nerve. That is anterior cutaneous nerve entrapment syndrome (ACNES), and the bedside clue there is Carnett’s test, where the spot stays as tender or gets worse when you tighten your stomach muscles. In a Dutch cohort of 139 patients with suspected ACNES, 94 (81% of those analyzed) had their pain at least halved by a first lidocaine injection at the tender point (Boelens 2011).
In clinical examination, the Tinel-positive point is one of the most useful clues. You ask the patient to identify the most tender spot on the scar and palpate it. Gentle tapping with a fingertip at that point reproduces the patient’s typical burning radiating pain. A focal point that consistently reproduces the radiating quality of the pain strongly suggests nerve entrapment until a block says otherwise.
How we diagnose
The diagnostic procedure is an ultrasound-guided TAP-plane nerve block at the Tinel-positive level. Performed in our procedure suite at 369 Lexington Avenue. Total visit time from check-in to walk-out: about 30 minutes.
Technique: with the patient supine, the abdominal wall anatomy is identified by ultrasound (external oblique, internal oblique, transversus abdominis, and the lateral edge of the rectus sheath at the Tinel-positive level). A thin needle is advanced under direct ultrasound visualization into the plane between the internal oblique and transversus abdominis at the Tinel-positive level. After negative aspiration, a small volume of local anesthetic is injected. Spread is observed in real time — a successful injection produces a hypoechoic plane between the two muscle layers along the lateral incision edge.
The diagnostic effect is immediate. Within 10–15 minutes, the burning pain should clearly ease if that nerve is the source. A clear drop in the usual pain while the anesthetic works is a positive block. It makes the nerve the likely source, not a certainty, and there is no universal cut-off: the relief threshold and the number of blocks follow the clinical question and your insurance plan’s policy. The patient keeps a pain diary every 30 minutes for the next four hours and at intervals over the next several days, which shows how long the relief lasts.
Some patients get lasting relief from the injection itself, though in the largest series that was a minority (see below). For patients who respond clearly to the diagnostic block, the next step is referral to a surgeon who focuses exclusively on peripheral nerve entrapment. The diagnostic block is the gate to that referral. Without it, the workup defaults to the wrong differential.
Treatment ladder and when surgery is the right call
Some patients with Pfannenstiel-incision nerve entrapment settle with blocks alone. Many do not. In the largest Dutch series, 186 women were treated for this problem, injections gave lasting relief to 13%, and 144 went on to neurectomy (Verhagen 2018).
Step 1 — neuropathic-pain medication. Gabapentin or pregabalin, titrated. Tricyclic antidepressant or SNRI for patients who do not tolerate gabapentinoids. A topical 5% lidocaine patch over the Tinel-positive band helps some patients.
Step 2 — ultrasound-guided diagnostic nerve block. The trial injection described above.
Step 3 — surgical referral. When the trial injection clearly relieves the usual pain, Dr. Movshis refers to a surgeon who focuses exclusively on peripheral nerve entrapment. The usual operation, a neurectomy, removes the trapped segment of the ilioinguinal and/or iliohypogastric nerve. It is usually not done by the original obstetric or gynecologic surgeon. In a Dutch series of 22 women, 73% rated their satisfaction as good or excellent at a median of two years (Loos 2008). In a larger follow-up from the same center, 54% of the 101 women who answered had no or only mild pain almost five years after surgery, and two in three reported at least half their pain gone (Verhagen 2018). Numbness in the nerve’s skin territory is expected afterward. Modal Pain coordinates the referral directly and provides the surgical team with the documented diagnostic-block response, the operative report from the index Pfannenstiel surgery, and any imaging that has been performed.
Step 4 — peripheral nerve stimulation referral. For refractory cases, percutaneous PNS at the affected nerve is an option that requires referral to an implanting specialist. It has FDA clearance, with evidence from a randomized trial in peripheral nerve pain and small case series (Deer 2016).
Surgery is not the goal of treatment. The goal is to identify the pain generator first. A clear response to the trial injection is what tells the surgeon which nerve to address.
For referring physicians
When referring a patient with persistent Pfannenstiel-scar pain >3 months after C-section, hysterectomy, or low-transverse pelvic surgery, send: the operative report from the index surgery, any post-operative imaging (transvaginal ultrasound, MRI of the pelvis), the patient's prior medication trial history, and a note on whether the pain is cyclical (suggests endometriosis component) or non-cyclical with burning quality (suggests neuropathic). We document a Tinel test at the consultation, run an ultrasound-guided diagnostic block at the lateral incision edge, and send notes back to the referring gynecology or obstetrics practice as requested or as needed. For patients with a clear block response, we coordinate referral to a surgeon who focuses exclusively on peripheral nerve entrapment and provide the surgical team with the diagnostic documentation they require.
Ready to evaluate your post-Pfannenstiel pain
If your C-section scar pain has persisted more than three months and a gynecologic workup has not produced an answer, the next step is a nerve-focused evaluation, which often leads to an image-guided diagnostic block. Same-week new-patient consultations are available at 369 Lexington Avenue in Midtown Manhattan.
Verify your insurance covers a post-Pfannenstiel pain workup Book a same-week consultation
Or call (646) 290-6660.
If you are not ready to book, the Post-Surgical Nerve Pain Self-Assessment is a reasonable next step — four to six minutes, and it will tell you whether your scar pain fits the entrapment pattern or points somewhere else. The result is yours to take to any physician.
For the broader framework on chronic post-surgical nerve pain, see the post-surgical and iatrogenic nerve pain page.
References
This article is reviewed against the peer-reviewed literature. Citations retrieved from PubMed.
- Boelens OB, Scheltinga MR, Houterman S, Roumen RM. Management of anterior cutaneous nerve entrapment syndrome in a cohort of 139 patients. Ann Surg. 2011. doi:10.1097/SLA.0b013e31822d78b8 · PubMed
- Loos MJ, Scheltinga MR, Roumen RM. Surgical management of inguinal neuralgia after a low transverse Pfannenstiel incision. Ann Surg. 2008. doi:10.1097/SLA.0b013e318185da2e · PubMed
- Verhagen T, Loos MJ, Mulders LG, Scheltinga MR, Roumen RM. A step up therapeutic regimen for chronic post-Pfannenstiel pain syndrome. Eur J Obstet Gynecol Reprod Biol. 2018. doi:10.1016/j.ejogrb.2018.10.045 · PubMed
- Whiteside JL, Barber MD, Walters MD, Falcone T. Anatomy of ilioinguinal and iliohypogastric nerves in relation to trocar placement and low transverse incisions. Am J Obstet Gynecol. 2003. doi:10.1016/s0002-9378(03)00934-7 · PubMed
- Zondervan KT, Becker CM, Missmer SA. Endometriosis. N Engl J Med. 2020. doi:10.1056/NEJMra1810764 · PubMed
- Deer T, Pope J, Benyamin R, et al. Prospective, Multicenter, Randomized, Double-Blinded, Partial Crossover Study to Assess the Safety and Efficacy of the Novel Neuromodulation System in the Treatment of Patients With Chronic Pain of Peripheral Nerve Origin. Neuromodulation. 2016. doi:10.1111/ner.12381 · PubMed
Frequently Asked Questions
It can. Most nerve pain after a C-section starts in the first weeks to months, but some patients first notice it much later, sometimes after a second pregnancy, a weight change or another abdominal surgery. Late onset is less well studied. One likely explanation is that an ilioinguinal or iliohypogastric nerve has been quietly irritated by suture or scar at the outer end of the Pfannenstiel incision, and a later change in the abdominal wall makes it symptomatic. The workup is the same whenever it started.
Quality and pattern. Nerve pain is burning, electric, lancinating, or 'stabbing,' often with allodynia (light touch to the affected skin hurts). Adhesion pain is dull, deep, and dragging — worse with motion, often crampy. Nerve pain has a positive Tinel sign: tapping at a specific point on the lateral incision edge reproduces the radiating pain. Adhesion pain does not have a Tinel sign. The diagnostic block — ultrasound-guided TAP-plane block at the lateral incision edge — usually eases nerve pain within 15 minutes and does not change adhesion pain. No test is perfect, so the block result is read together with the exam.
Scar endometriosis is real, but it usually produces cyclical pain (worse during menses) and a tender lump within the scar that can swell around menstruation. Ultrasound often shows a discrete nodule, and removing the nodule and examining the tissue confirms it. Nerve entrapment looks different: burning pain, skin that hurts to light touch, a positive Tinel sign, no cyclical pattern and no lump. Scar endometriosis is uncommon, while nerve entrapment is reported after about 2 to 4% of Pfannenstiel incisions. Both can coexist, and each has its own treatment path.
An ultrasound-guided injection of a small volume of local anesthetic into the muscle plane where the nerve runs, at the level of the Tinel-positive point near the end of the scar. Within 10 to 15 minutes, the usual burning pain should ease clearly if that nerve is the source. That makes the nerve likely, not certain. Local anesthetic alone gives several hours of relief, which is enough to answer the diagnostic question. A minority of patients get lasting relief from injections alone, and a clear response leads to referral to a surgeon who focuses exclusively on peripheral nerve entrapment.
Not always. When a trial injection confirms the nerve and the pain persists, an ilioinguinal or iliohypogastric neurectomy by a surgeon who focuses exclusively on peripheral nerve entrapment is the main surgical option. In a Dutch series of 22 women, 73% rated their satisfaction as good or excellent at a median of two years. In a later series from the same center, 54% had no or only mild pain almost five years after surgery, and 8% had pain return after initial relief. The operation removes the trapped nerve segment and leaves numbness in its skin territory.
Not in any known way. Image-guided ilioinguinal and iliohypogastric blocks act on small nerves in the abdominal wall and are not known to affect fertility or future pregnancies. Surgical neurectomy, when needed, leaves the uterus and the rest of the pelvis undisturbed. If you are pregnant, breastfeeding, or planning a pregnancy soon, tell us before any procedure, because the timing and the medications used may need to change.
Most commercial PPO plans cover image-guided peripheral nerve blocks for chronic post-surgical pain, typically with prior authorization. We check your benefits and go over what your plan covers and any expected cost by phone before your visit, so there are no surprise bills. Most commercial PPO plans are accepted, including Aetna, Anthem Blue Cross Blue Shield, Cigna, Empire Blue Cross Blue Shield, the Empire Plan, Oscar, Oxford, UMR and UnitedHealthcare. The practice does not accept Medicare, Medicaid, HMO plans, or workers' compensation. Check your plan or call (646) 290-6660.
