Lichtenstein’s flat-panel repair is considered a milestone in hernia repair in the 20th century because Lichtenstein pioneered the concept and method of tension-free hernia repair and advocated the use of local anesthesia for this type of procedure, with a return to daily life 24 hours after surgery. However, Lichtenstein emphasized that this procedure requires a trained surgeon and cannot be classified as a “minor surgery”. The main points of surgical repair are 1. Anesthesia and subtenon release of the extra-abdominal oblique muscle. Local anesthesia is preferred, and during the anesthesia process, the four innervated nerves in the inguinal region should be blocked in layers according to their characteristics [2]. There is an anatomically closed cavity in the inguinal canal under the extra-abdominal oblique tendon membrane, called the “first gap” or “inguinal box”, where the hernia repair is mainly performed. After incision of the extra-abdominal oblique tendon membrane, the upper flap is freed to the superficial surface of the internal oblique muscle about 5 cm from the edge of the inguinal ligament, down to the inguinal ligament reflex and the iliopubic bundle, 1.5-2.0 cm below the internal suprapubic node and 2 cm above the internal ring. 2. Freeing the spermatic cord and hernial sac The inguinal hernia may have a thousand variations, but the penetration of the spermatic cord at the mouth of the external ring is constant. A good freeing of the spermatic cord is important to locate the hernia sac and to reduce the number of misssed hernia. The spermatic cord should be released starting from between the levator sheath and the tendinous tissue attached to the pubic bone (no blood vessels at this anatomic level), and the spermatic cord (round ligament in women) should be lifted with Babcock’s forceps (appendicular forceps). In the case of a hiatal hernia, the hernia sac must be closely associated with the spermatic cord (this is determined by herniogenesis and formation) and the hernia sac is located medially in front of the spermatic cord. In the case of a straight hernia, the hernia sac is basically unconnected to the spermatic cord and is located in the straight hernia triangle. The electric knife separates the loose tissue between the spermatic cord and the transverse abdominal fascia, and a small amount (1 cm) of the levator muscle is cut longitudinally upward with the knife or with the electric knife (adjusted to low power so as not to injure the spermatic cord vessels), and the levator muscle is continued upward with the vascular clamp to separate the levator muscle and free the spermatic cord, avoiding complete stripping or removal of the levator muscle fibers from the spermatic cord. Be careful not to separate the spermatic cord below the level of the pubic tuberosity and below the opening of the external ring to prevent complications such as ischemic orchitis and testicular atrophy.Lichtenstein believes that mechanical pressure and ischemic changes due to the ligation of the hernia sac are important causes of postoperative pain. Therefore, for inguinal hernias with a small hernia sac, after freeing the hernia sac from the spermatic cord at a high level (beyond the hernia sac neck), the hernia sac can be turned directly into the abdominal cavity without ligation, and existing studies have shown that the hernia sac without ligation does not cause an increased chance of recurrence. In cases where the hernia sac enters the scrotum, it is advisable to transect the sac at a point equivalent to the midpoint of the inguinal canal, suture it proximally and turn it into the peritoneal cavity, leaving the distal end in place after hemostasis, but the anterior wall of the distal hernia sac should be cut to prevent postoperative fluid accumulation. In case of larger lipomas in the spermatic cord, they can be removed. For direct inguinal hernia with a large hernia sac, the sac should be sutured with absorbable thread after retraction. The inguinal region should be carefully explored for the presence of a combined hernia. The simplest and most practical technique is to routinely insert a finger after opening the hernia sac to probe for the presence of a compound hernia. Patch placement The size of the patch depends on the size of the local defect, usually 7×15 cm, and is fixed with sutures along the edge of the “inguinal box”, medially 2 cm above the pubic tuberosity, 3-4 cm above the Hesselbash triangle, and laterally 5-6 cm above the internal ring. The patch was placed on the base of the inguinal canal and behind the external oblique abdominal tendon. Since the inguinal region is an area of easy movement, fracture, displacement or curling of the patch here can lead to failure of the tension-free hernia repair. The medial end of the patch is cut into a circular arc in line with the medial angle of the inguinal canal and fixed to the anterior sheath of the rectus abdominis muscle over the pubic symphysis with a single strand of nonabsorbable synthetic suture rather than to the periosteum of the pubic symphysis, which can cause periostitis and postoperative pain. The medial corner of the patch should be sutured overlapping the anterior rectus abdominis sheath by 1-1.5 cm, which is crucial to prevent recurrence. The lower edge of the patch should be properly fixed to the inguinal ligament, generally with no more than 3-4 consecutive sutures, too close sutures can easily lead to ligament tears. The suture need not exceed the inner ring, otherwise it is easy to damage the femoral nerve. The sutures should be wide and shallow and not too deep to avoid injury to the femoral vessels. The upper and lower caudal lobes of the patch are cut in a dovetail shape on the outside, and the caudal part of the patch is crossed behind the spermatic cord, which is located between the two caudal lobes that have been cut. The lower edges of the upper and lower caudal lobes are fixed to the inguinal ligament with a single stitch each with a nonabsorbable suture. The crossover of the caudal lobes of the two patches produces a structure that resembles a normal transverse abdominal fascia suspension, reconstructing an intact, normal-sized internal ring and preventing recurrence of the hernia at the internal ring. The upper edge of the patch is intermittently sutured to the internal oblique abdominal muscle. Clinical studies have shown that the polypropylene patch can shrink up to 20% after placement in the body. Therefore, when the patient is completely tension-free in the lying position, the patch should be kept moderately relaxed (in a dome like structure), and it is not necessary to pursue complete flattening, so that the patient can have a compensating margin when doing standing, coughing and other abdominal pressure raising movements or when the patch shrinks to achieve true tension-free. Special attention should be paid to the protection of the nerve during this repair. The inferior iliac abdominal nerve is usually observed after incision of the extra-abdominal oblique tendon membrane, and attention should be paid to the protection of the inguinal iliac nerve and the genital branch of the genitofemoral nerve that accompanies the spermatic cord when the spermatic cord is lifted. The advantages and disadvantages of plain patch repair The technique of tension-free hernia repair has undergone development in recent decades, especially with the deepening of the understanding of the pathophysiological process of hernia formation, and gradually formed the tension-free hernia repair technique represented by the Lichtenstein procedure. This technique is known as the “gold standard” in the field of tension-free repair. Its advantages are: 1. It is suitable for adult inguinal hernia of type II-IV (including compound hernia). 2. The efficacy of the procedure is precise, and the patient can resume daily work and life very quickly. 3. The learning curve for the surgeon is short and easy to master. However, there are still some drawbacks or shortcomings of this procedure: 1. In terms of repair concept, Lichtenstein is repairing the posterior wall of the inguinal box, rather than repairing the defect in the pubococcygeal foramen area. In contrast, the Prilling hernia device (PHS) and Kugel patch are patches that protect the entire pubococcygeal muscle foramen area by extending the patch in the preperitoneal Bogros gap, which is more comprehensive in scope and more in line with the modern concept of inguinal hernia anatomy. From the anatomical level, the Lichtenstein method is more anterior than the preperitoneal repair (i.e., near the superficial layer of the abdominal wall), and the coverage of the patch is smaller, which is the greatest shortcoming. 2, The method cannot repair femoral hernias. The patch must be sutured and fixed during the repair process, and the nerves may be injured during the suture fixation process, so some patients may have chronic pain in the inguinal region. 4. After the repair of this procedure is completed, the spermatic cord is placed above the patch, and the vas deferens is not a simple duct, but a muscular duct surrounded by smooth muscle. The formation of scars due to the adhesion of the patch may have an impact on the sexual function of men after surgery, which can be manifested as ejaculation pain and retrograde ejaculation. 5. It is for these reasons that a suitable patch should be selected for the Lichtenstein procedure. If it is a thick mesh of heavy quality, the suture can be reduced because of the heavy reaction to quickly form a scar, but the scar can also have an impact on male sexual function, and if a light mesh with large mesh holes, or expanded polytetrafluoroethylene mesh (ePTFE) is chosen, it must be sutured to fix the exact. So it is difficult to have the best of both worlds. The surgeon must fully understand the above issues, weigh the pros and cons, and make a choice.