Daytime surgery model has developed rapidly in recent years. Day surgery mode refers to a surgical mode in which patients have completed preoperative examination before admission, make an appointment for surgery, stay in hospital on the same day, operate on the same day, and leave hospital under short-term observation. Inguinal hernia is a common clinical disease. According to statistics, every year there are more than 20 million new cases all over the world, and more than 3 million new cases every year in our country. The inguinal hernia operation plays an important role in the daytime surgery. The tension-free, minimally invasive, postoperative pain, comfort and cost of inguinal hernia treatment have always been the focus of surgeons [9]. For elderly patients, reducing anesthesia complications, reducing postoperative pain, shortening postoperative braking time and hospital stay, and resuming daily life as soon as possible are also a manifestation of minimally invasive effects. We believe that the concept of minimally invasive should not be limited to surgical methods, and it is a surgical concept and technical system to minimize the local trauma and systemic reaction caused by surgery while removing lesions as accurately as possible. Local nerve block anesthesia for elderly inguinal hernia has been recognized by physicians [10]. It can be performed for patients with heart, lung, brain and other diseases, even oral anticoagulants [11]. It not only expands surgical indications, improves surgical safety but also avoids respiratory and circulatory complications that may be caused by general anesthesia and epidural space block anesthesia. Reduce the incidence of postoperative urinary retention, compression injury caused by prolonged bed rest and precipitating pneumonia and other complications [12]. There are more and more reports on the treatment of senile inguinal hernia with local nerve block guided by ultrasound [13].

Ilioinguinal nerve and ilioinguinal inferior ventral nerve are two nerves closely related to inguinal hernia surgery, both of which send out muscular branches to jointly innervate abdominal wall muscles, while the ilioinguinal inferior ventral nerve provides cutaneous branches and terminal branches of ilioinguinal nerve to innervate sensory sensations in the inguinal region. This is the anatomical basis of local nerve block in inguinal hernia surgery. In clinical practice, it was found that the ilioinguinal nerve and ilioinferior abdominal nerve in most patients showed two oval structures between the internal oblique muscle and the transverse abdominal muscle in ultrasonic images, with low echo shadow inside and high echo shadow around the outside. Under the guidance of ultrasound, the gap between the internal oblique muscle and the transverse abdominal muscle was accurately found, and the ilioinguinal nerve and ilioinferior abdominal nerve were accurately blocked [14]. For a small number of patients with delicate nerve anatomy, variation in course and unclear nerve structure in ultrasound image, appropriate increase of local anesthetic dosage can also achieve good blocking effect by forming "water sac" between the internal oblique muscle and the transverse abdominal muscle.

This study suggests that the application of local anesthesia in tension-free inguinal hernia repair in the elderly has the following advantages: (1) Local anesthesia has little impact on human respiration and circulation, and high safety, avoiding the risks brought by epidural anesthesia catheter, and epidural anesthesia on sympathetic ganglion and spinal nerve block after vasodilation, peripheral resistance decreased, reduced cardiac blood volume, blood pressure often fluctuate significantly, so local anesthesia is particularly suitable for the elderly with cardiovascular and cerebrovascular diseases. (2) Partial anesthesia does not affect patients’ activities, avoiding bed immobility accompanied by general anesthesia or regional anesthesia, which is beneficial for preventing lung complications and lower extremity deep vein thrombosis in the elderly. (3) Partial anesthesia does not affect the bladder urine control function of patients, preoperative often do not need catheterization, postoperative urinary retention occurs less, the elderly with mild or severe prostate hyperplasia, no catheterization will not increase the pain. (4) If there is no pain after the operation, the time to get out of bed can significantly shorten the length of hospital stay and reduce the cost of hospitalization.

This study is a single-center retrospective study with limitations. More relevant data, such as case numbers, multicenter or prospective studies, are expected to support this. Nerve block anesthesia requires high technical and experience requirements of anesthesiologists and requires special training. The median follow-up time in this study was only 4 months, and longer follow-up time was needed to provide more accurate data for immediate and long-term postoperative complications.

In conclusion, compared with open surgery under epidural anesthesia, tension-free repair of senile inguinal hernia under ultrasound-guided local nerve block under daytime diagnosis and treatment mode has the advantages of less pain and faster recovery, which is safe and feasible.