Post-operative Inguinodynia from Hernia Surgery
As an expert in hernia surgery and a referral center for difficult hernia patients, one of the most challenging problems that I have encountered with increasing frequency is post-operative inguinodynia from hernia surgery. This term refers to persistent groin pain after hernia repair. A host of possible causes for the pain have been implicated. Men are primarily affected by this syndrome but women have also been known to be plagued by inguinodynia. In this article, I will present an overview of this problem and attempt to give insight on this difficult and costly syndrome which has become increasingly prevalent in the workers’ compensation arena, as well as in the private sector.
This relatively newly-recognized syndrome has become a modern day plague on the claims examiner, the treating surgeon, and the patient. Diagnosis, etiology, treatment, and generally interacting with these patients are challenging for all those involved. An integral part of this problem is knowing if the patient is a reliable historian, psychologically sound, and whether the patient is merely posturing for secondary gain. Personally, I have seen inguinodynia appear months or years after hernia surgery, and only after the injured worker retained legal representation—usually due to an unrelated issue such as back pain. Interestingly, the most current surgical literature reveals that over 90% of inguinodynia occurs in workers’ compensation patients. Of those 10% remaining patients with inguinodynia, only a fraction of them is without litigious intent. This has prompted some authors to believe that inguinodynia is synonymous with the patient posturing for secondary gain and using symptom amplification (see Table 1). This situation has been in question until recently.
Neuropathy of Inguinodynia
Inguinodynia can occur in the immediate post-op period or can occur months after hernia surgery. The most difficult scenario presents when the patient experiences a window of three to six months after surgery without complaints then returns complaining of pain on the operated side. Then there are those patients with obvious pathology who present with unrelenting pain without reduction in intensity of the pain from the date of surgery. 15 to 30% of hernia patients will develop a post-op neuropathy or a nerve irritation symptom complex. Symptoms of neuropathy are usually described as burning with irradiation to the upper inner thigh, lower abdomen, testicle, scrotum, base of the penis, or labium. A list of potential causes of inguinodynia is presented in Table 2.
Originally, the supposed culprit causing the neuropathy was believed to be the mesh per se. This gave the senior surgeons probable cause to condemn the use of mesh and continue the archaic Bassini, McVay, or other non-mesh repairs. Subsequent research, however, showed that the mesh did not cause the neuropathy but, instead, was traced to the surgeon’s surgical technique. With the use of mesh, more detailed anatomic dissection and attention to sensory nerve anatomy was required. Surgeons were actually incorporating the sensory nerve with the suture used to affix the mesh, thus causing the neuropathy. With exquisite attention to avoiding the sensory nerves, the incidence of neuropathy plummeted. Recognition of the precise anatomy of the ilioinguinal, iliohypogastric, genito-femoral, and lateral femoral cutaneous nerves is paramount.
Symptoms emanating from the neuro-pathy generally resolve spontaneously in a few months only if the neuropathy is from inflammation. Oral anti-inflammatories, ice, or heat are helpful at times. More severely affected patients require injections with local anesthetics and corticosteroids to reduce or eradicate the neuropathy symptoms. A series of three injections, spaced one week apart, may be necessary to control the symptoms of burning or searing pain. A minority of neuropathy patients are a failure on medical therapy and therefore require surgical re-intervention. Re-operation may be necessary if there is a true mechanical restrictive component whereby the nerve(s) are irreversibly involved and treatment with alcohol ablation and radiofrequency ablation have been attempted and failed. Some pain treatment anesthesiologists have gone so far as to use an implantable dorsal column stimulator in attempts to control the pain.
The newest surgical studies and research support surgical intervention with removal of the three main sensory nerves of the groin. These nerves are the ilioinguinal, iliohypogastric, and genito-fem-oral nerves. Removing only one nerve and/or attempting a neurolysis (freeing the nerve from scar) has been fraught with failure to eradicate the painful symptoms. This treatment is incomplete and requires further expensive interventional treatment.
As a result, the optimum treatment regimen would be to perform a triple neurectomy and neuroplasties or implantation of the nerve ends into pristine muscle tissue or “virgin soft tissue.” Implantation is done to prevent neuroma formation. Prior alternative nerve transposition did not yield optimum results because the transposed nerve was irreversibly damaged and more scar would form. This was a set- up for prolongation of the neuropathy symptoms and eventual triple neurectomy.