Patients present to their physicians and are referred to a surgeon for evaluation of groin pain with a suspicion of an undetectable hernia. This pain must be tenaciously evaluated and correlated with diagnostic findings. If a hernia does NOT cause the pain, pain will persist postoperatively. Patients with preoperative pain with hernias also have an increased risk of postoperative pain. There are other reasons for postoperative pain that should be discussed preoperatively. All of the causes of pain in patients without hernias can be experienced by patients who have had hernia surgery and might not be related to the surgery.
For example, a young man who notices an uncomfortable hernia after weight lifting has a repair and recovers uneventfully with no residual symptoms for three years, then has groin pain after a wrestling match in college. No hernia recurrence is found and the pain is in the lower portion of the rectus abdominus muscle where he has strained the structures of abdominal wall muscles. Some minor aches, pulling, stiffness or limited numbness will still improve after this point.
On the other hand, patients who have persistent pain especially those with a painless original hernia are of greater concern. For the purpose of clarification, a problem that persists six months after surgery is a long-term problem.
Pain is a significant complaint after the early phase of wound healing. Significantly, the same pain might have been noted immediately after surgery and continuously persisted requiring consistent narcotic usage. Occasionally patients note severe pain immediately after anesthesia. Prompt reoperation might be required to resolve a technical anatomic problem.
The pain might gradually evolve, be under the wound, and in the area of the preoperative hernia bulge or the pain might radiate from the wound into the thigh, pubic area or testicle. Motion or positional changes might worsen symptoms. If actual pain prevents return to normal activity and return to work after 4-6 weeks, the complaints requires a remedy.
Nerve entrapment produces burning pain. Radiation of discomfort into the scrotum might be felt for a week or two after surgery but persistence for months is alarming. Nerve entrapment occurs because something is continuously irritating the nerve. This can result from angulations of the re-routed nerve, compression by an aperture produced by tight closure of a rings or swelling of the tissues exiting the shared ring, or subsequent thick scar formation that continues to compress the nerve. A nerve might be in a position where it courses over the edge of an irritating mesh or fibrosis from wound healing, with or without mesh, that entraps a nerve.
Pain can occur because of changes or loss of nerve structure or neuroma formation. Preoperative injury to the nerve by stretching or compression by the original hernia mass may not recover after hernia repair causing pain to persist. At the original surgery the surgeon might have noted a thin stretched out nerve or a “traumatic neuroma” at the site of continuous irritation. Experienced surgeons who detect this finding might excise the nerve to avoid postoperative pain. Pain can result from devasularization of the nerve during mobilization. Sutures might entrap a nerve. Tight tissues can squeeze a nerve. Most resorbable sutures are gone by six months and resolution might follow resorption of the suture. If permanent suture material is used, reoperation usually will be required to resolve this problem but should be done after a diagnostic nerve block (injection of local anesthetic to the nerve) proves that the pain can be relieved by action focused on the nerve. Resolution of this problem might therefore require reoperation in order to free up and frequently intentionally transect the nerve. Numbness is usually preferable to steady pain. Other inguinal surgeries performed through Bikini (Pfannensteil) incisions for C-section or hysterectomy can have similar pain.
Early recurrence might produce immediate and persistent postoperative pain. Causes include suture line disruption, herniation at the perimeter of the repair, herniation under a mesh, and undetected persistent nearby hernias. A recurrent hernia protrusion usually becomes obvious within six months but might be difficult to detect because of scar formation in early stages of wound healing. Some recurrent hernias are immediately detectable.
The earliest recurrence that I ever saw occurred when I was assisting during training. At that time, strong synthetic sutures, with the exception of wire, were not available. Silk was the dominant suture material and the Bassini technique, requiring tension, was used. As the awake, very muscular patient moved from the operating room table to the stretcher, I heard a rhythmic sequence of pops representing breakage of the interrupted multiple sutures used in repair.
Recurrence also occurs later in the first year due to gradual thinning and resorption of the scar, possibly in repair created under tension, during wound maturation after about three months. High tension repairs also have more postoperative discomfort in early stages or the immediate postoperative phase might have been uneventful.
The Shouldice Clinic showed that recurrence is less likely if permanent sutures are used. No mesh was used. In other words, the suture continues to support the repair.
Recurrence is rare when mesh is properly used. Irving Lichtenstein showed that tension can be reduced by using mesh and postoperative pain is also reduced.
Postoperative recurrence rates from around 25% decreased to less than two percent with both the Shouldice and Lichtenstein Tension free technique. Laparoscopic methods, all using mesh, also have recurrence rates of 1-2%. This information is derived from peer review literature with agreement by surgeons dedicated to hernia surgery.
Surgeons, however, intuitively know that we do not have a clear idea of overall recurrence rates because reoperation is common. Recurrences are quoted at varying times, i.e. after one or five or ten years. Follow up is almost always incomplete then and thereafter. Patients with recurrences frequently will not return to the same surgeon. In some studies, patients with risk factors for recurrence are excluded, e.g.; obesity, neoplasm, diabetes, elderly, asthmatics, prostatism, constipation and immune compromise.
Testicular atrophy is rare in initial hernia repairs but a real risk of about 3% in recurrent open hernia repairs because mobilization of the spermatic vessels from scar during recurrent repairs can be very difficult. The same scar makes it hard to mobilize nerves. Loss of the arterial supply will result in loss of the gonad. After a short period of testicular pain, swelling of the testicle (not the scrotum) is noted, pain decreases, and then over the next three months the testicle shrinks. Testicular injury is rare after initial hernias unless they are very large and long neglected, treated with truss and involved in scarring and anatomic distortion. Avoidance of the area of scarring resulting from the initial surgery is best accomplished by a laparoscopic approach which repairs the hernia in a fresh unscarred tissue plan, an “end run.”
Persistent infection – A small percentage of initial hernia repairs are complicated by wound infection which are generally resolved with treatment. However, deep infection can be perpetuated by mesh and associated with persistent pain. Radiologic evaluation will confirm this diagnosis. In general, reoperation with removal of mesh is required.
Uninfected Mesh and pain – Postoperative pain can occur with essentially equal likelihood with and without mesh. Three dimensional, multi-layered mesh plugs, however, seem to have a more impressive relationship to postoperative pain.
These plugs having a cone shape and are filled by layers of mesh that are placed within defects and secured with sutures, thus plugging rather than repairing the defect. Repairs are usually in an essential two dimensional plane. Plugs are deeply three dimensional. The directional depth of the leading edge can irritate various pelvic structures including multiple pelvic nerves. Fibrosis of wound healing can anchor the mesh on these structures resulting in progressive and persistent pain that increases with movement and position and interferes. Patients decide that function is impeded and want reoperation to remove the plug despite risks. This is a tedious microsurgical procedure for removal and revision of the repair. Results are good but the experience and skills of the surgeon are of great importance. Here is a situation where disallowance of choice by Insurance coverage is a great disadvantage to the patient.
Pain reception is a very individual matter. Small processes can produce a lot of pain and vice versa. This ancient knowledge is portrayed by “the princess and the pea” parable. The same stimulus can be felt by different people with different intensities. The same intensity can be interpreted at different levels by a sensitive person more than a stoic person. The desire to avoid surgery, whether from fear or inconvenience, will alter the patient’s interpretation of pain. Clinical scales might be useful. Function is an important indicator. Can a pilot sit comfortably and safely fly? Is walking impeded? Is concentration limited? Decision to reoperate must be a partnered effort by the patient and surgeon weighing symptoms, clinical findings, risks and benefits, expectations, advantages and disadvantages.