There is an increase in the number of patients with lumbar diseases, and a large number of them need lumbar surgery. As the obvious pain after lumbar surgery, postoperative analgesia is often needed. However, patient-controlled intravenous analgesia and epidural analgesia, which are commonly used in clinic, have their own shortcomings[4, 24]. Side effects such as nausea and vomiting caused by postoperative opioid use result in poor postoperative experience, reduce patient satisfaction, and are not conducive to rapid recovery. In recent years, many researchers have used ESPB for postoperative analgesia and found that the analgesic effect is good. The local anesthetics injected during ESPB spread widely and could produce the effect of paraspinal block, therefore, the block range was wide and could last until a period of time after operation. Furthermore, ESPB can reduce the stimulation of operation, reduce the soft tissue injury caused by pulling muscle during operation, and then effectively reduce the use of perioperative analgesia and anesthetics[14, 26, 27]. However, there are few studies on ESPB for postoperative analgesia of lumbar spinae surgery patients. Therefore, it is necessary to summarize the relevant clinical studies. Eleven studies of ESPB for lumbar surgery were included, and data from 171 patients were extracted and analyzed. Interestingly, all included studies have shown that ESPB can reduce postoperative opioid consumptions and pain scores in patients undergoing lumbar surgery. Furthermore, ESPB could improve patient satisfaction and reduce the side effects caused by opioid use without block-related side effects. ESPB can effectively relieve postoperative pain, reduce opioid consumption and improve patient satisfaction, in line with ERAS (enhanced recovery after surgery).
It has been reported that pain is obvious at 4 hours after lumbar surgery and relieved after 72 hours. What is more, regional block anesthesia can help patients reduce pain and other discomfort[18, 29]. Interestingly, Singh found that when 0.25% 20ml bupivacaine was injected on both sides of the T10 plane, the 6th hour NRS score was low, however the 8th hour NRS score was high after lumbar surgery, which suggested that the ESPB could last until 6 to 8 h after operation. The duration of ESPB block was related to the type and dose of local anesthetics. However, the safe doses of different local anesthetics were different. For example, the unilateral injection volume of ropivacaine was 20 to 40ml, the concentration was 0.25% to 0.5%, and the total safe dose was 150mg. It is recommended that each side of bilateral block should be given 0.375% ropivacaine 20ml in adults[15, 31]. Therefore, the dose or concentration can be increased appropriately to prolong the analgesia time and help the patients to get through the most painful stage after operation.
The puncture plane was from T8 to L4, and the follow-up time was from 10 h to 72 h. However, in different studies, patients have different basic analgesia programs, and some researchers pay attention to the use of rescue painkillers, while some studies focus on the total amount of postoperative analgesia drugs[14, 32]. Furthermore, Different basic analgesia regimens may cause differences in pain scores. As a result, there is great heterogeneity among different studies, and the results can not be quantitatively synthesized and analyzed. At the same time, it is suggested that we should pay more attention to the primary outcome indicators in the design of clinical trials in the future. The recently reported protocol of ESPB for postoperative analgesia of lumbar surgery is worthy of reference. At the same time, it is important to note that little attention has been paid to the effects of ESPB on the use of intraoperative analgesic drugs and muscle relaxants. Only one case report mentioned that erector muscle block could effectively reduce the use of analgesia and muscle relaxant drugs during the perioperative period of spondylolisthesis correction surgery, and appropriate hypotension was beneficial to surgical visual field exposure and operation. Reducing the use of perioperative anesthetics can not only reduce the cost of hospitalization, but also reduce the possible side effects of extensive use of anesthetics. At present, some scholars believe that perioperative use of opioids can affect the immune function of patients, and may be associated with the poor prognosis of tumor patients. At the same time, reducing the use of perioperative opioids may reduce the risk of tumor recurrence[34, 35]. From this point of view, it seems that the effect of ESPB on intraoperative opioid dosage is also worthy of attention. On the other hand, the included studies did not seem to pay particular attention to the effect of ESPB on early out-of-bed activity and postoperative hospital stay in patients with lumbar spine surgery. Early out of bed activity and early discharge from hospital comply with ERAS, which is also the reason for the promotion of ESPB in patients undergoing lumbar surgery. At the same time, no adverse events related to ESPB were found in all the 11 studies, suggesting that ESPB was safe.
Recently, Turbitt and other experts have proposed that nerve block technology should not be limited to nerve block experts, but should be mastered as a basic technique by general anesthesiologists in order to be more widely used in clinic and benefit patients. However, due to the differences in clinical conditions in different areas, the clinical coverage of regional nerve block is still limited. Therefore, we should better proceed from the clinical practice, so that more anesthesiologists to master simple and practical cost-effective regional block technology. Because of its simple operation and low risk of infection, bleeding and spinal cord injury caused by puncture, ESPB should also be used as a basic operation technique for anesthesiologists. Although ESPB has been widely used in thoracic and abdominal surgery, the use of ESPB in lumbar surgery is still controversial. Some researchers believe that TILP block is better than ESPB in patients undergoing lumbar surgery. However, ESPB has the advantages of simple operation and less complications, and is more in line with the idea advocated by Turbitt and other experts to let general anesthesiologists master nerve block techniques and apply them. We believe that the clinical research quality of ESPB for lumbar surgery should be improved, and the mechanism of erector muscle block for postoperative analgesia and perioperative protection of lumbar spine should be further explored. At the same time, more general anesthesiologists are needed to master ESPB and apply it to patients undergoing lumbar surgery for the benefit of more patients.
Although we have strictly formulated the scheme of literature retrieval and data extraction, there are few research reports that can be included. Only 2 RCT articles were included, howerver the outcome could not be analyzed. Furthermore, the sample size of the two articles is small, and the random, blind method and research quality need to be improved. We need more large sample size, high quality clinical trials to explore the benefits of ESPB for lumbar surgery patients.