By: Kaitlin DePrez (edited by Dr. Trainor)
Inguinal hernia repairs are very common surgeries, but one of the potential long-term complications is persistent groin pain. Pain that persists longer than 3 months is considered chronic and can be diagnosed as chronic post-herniorrhaphy groin pain (CPGP) or neuralgia.1,2 It is estimated that some form of chronic postoperative pain or discomfort is present after inguinal hernia repairs in 10-12% of cases, however, the incidence has been reported as high as 63%.2,3 Risk factors for chronic groin pain following inguinal hernia repair include female gender, use of the Onlay mesh technique (which requires extensive suturing), recurrent repairs, and preoperative pain.3 The pain is thought to be the result of direct nerve injury to one or more of the inguinal sensory nerves or tension on these nerves following surgical manipulation.2 Interestingly, the use of mesh and laparoscopic (compared to open) surgeries are associated with lower rates of chronic pain.3,5
While surgical technique continues to be studied and modified in order to lower the prevalence of chronic pain, chronic groin pain is still a potential complication that can seriously impact a patient’s quality of life following one of these elective yet necessary surgeries.
Initial treatment recommendations for chronic post-herniorrhaphy groin pain/neuralgia (CPGP) include medical management with antiepileptic medications such as gabapentin or pregabalin, or antidepressants like duloxetine or tricyclic antidepressants.1,2 It is recommended that neuropathic medications be started early in patients with severe pain, but there has been no conclusive data on whether this reduces the development of chronic pain thereafter.6 Medications used to treat postoperative pain like opioids or NSAIDs are typically not as effective against chronic neuropathic pain, but topical agents can be tried as well.1
The next option in the stepwise approach involves groin nerve blocks with a mixture of lidocaine, corticosteroids, and hyaluronic acid.4 The GroinPain Trial in 2018 was the first randomized control trial to look at the effectiveness of inguinal nerve blocks compared to surgical removal of the implicated nerves (neurectomy).4 The three inguinal nerves of concern are the ilioinguinal nerve, iliohypogastric nerve, and genital branch of the genitofemoral nerve. In certain patients, the groin nerve block breaks the pain cycle and cures the post-herniorrhaphy neuralgia.1 In these patients, the injection can be repeated weekly until the pain relief becomes sustained. Nerve blocks can be done by targeting the ilioinguinal/iliohypogastric nerves directly via truncal blocks, compartmentally by injecting the transabdominal plane (TAP) where both nerves reside, or infiltrating the point of maximal pain within the groin scar (tender point infiltration, TPI). 2,4,7 They can also be done using either landmark-based or ultrasound-guided techniques, although there has been no real difference in outcomes.2
In other patients, the pain may be relieved initially but then become refractory to further nerve blocks. In these patients, destroying the nerve may be needed, by either percutaneous nerve ablation or surgical neurectomy.1 Nerve ablation is done in a similar manner to a nerve block, except that a neurolytic solution such as phenol or alcohol is injected, which destroys the nerve ending. This can also be done with radiofrequency ablation or cryoablation. Nerve ablation may not be a permanent solution since the nerves can still regenerate over time, but it can provide several months of pain relief in some patients.1
Surgery is typically a last option for treatment, and while it has been found to be the most definitive management for CPGP,1 it requires subjecting patients to yet another surgery. Neurectomy (nerve excision) has demonstrated a success rate ranging from 70-100% and can be done by excising either one or all three of the inguinal nerves.1,6 A selective neurectomy may be a reasonable option for patients with diagnostic nerve blocks of a single nerve, but it tends to have a lower success rate (around 50%) when compared to a triple neurectomy (around 90%).1,4
One alternative to surgery in patients with refractory CPGP is neuromodulation. There are many possible targets for neuromodulation and include the spinal cord (SCS), peripheral nerves (PNS), and the dorsal root ganglion (DRG). The evidence for this therapy in the treatment of CPGP is emerging and early studies show that it is an effective long-term treatment. In one prospective study examining DRG stimulation (DRGS) for the treatment of CPGP, nearly 90% of patients had significantly decreased pain during the trial period, as well as long-term pain relief at three years follow-up.8 Likewise, in the ACCURATE study, a larger cohort was examined and the rate of 50% pain relief was significantly greater in the DRG group when compared to an SCS group, suggesting that DRGS can better cover a specific painful area.8
The Denver Spine and Pain Institute can provide this full spectrum of pain care (up until the point of surgery) including medication therapy, physical therapy, peripheral nerves blocks, nerve ablations, and even neuromodulation. If you have been left with chronic groin pain after an inguinal hernia repair, reach out to The Denver Spine and Pain Institute today to learn about your options for pain relief.
Give us a call today to schedule an appointment with one of our excellent providers at The Denver Spine and Pain Institute. 303-327-5511.Schedule Now