In today’s aging society, osteoporotic vertebral compression fractures has become more common in clinical practice[14, 15]. OVCF refers to spinal fractures that occur with or without minor trauma due to decreased bone density and bone mass caused by osteoporosis as well as decreased bone strength, mainly manifesting as pain and limited movement in the chest, waist and back with or without neurological symptoms in the lower extremities. OVCF has an insidious onset with an increasing incidence rate year by year, whichseriously affects the elderly and especially postmenopausal women. 83% of the 100 patients in this study were women, accounting for the vast majority. The pain caused by OVCF seriously affects the quality of life, range of activity, and psychological mood of patients, while long-term bed rest could further lead to complications such as deep vein thrombosis in the lower extremities, pressure sores, and pulmonary infections, and may even endanger life. According to the relevant literature, the mortality rate of patients with OVCF for one year is significantly higher than that of the general population.
The primary surgical treatment means for OVCF is percutaneous vertebroplasty and percutaneous kyphoplasty (PKP). Vertebroplasty can enhance the stability and strength of the diseased vertebrae, while the high temperature of bone cement can inactivate the inflammatory factors in the vertebral body and reduce the nociceptive sensitivity of the spinal branches, so that the pain symptoms of patients can be improved after surgery. However, it is found that patients often have residual postoperative myalgic pain distributed along the erector spinae muscle, which even manifests distal pain radiation. According to the anatomy, the erector spinae muscle is innervated by the posterior branch of the spinal nerve which emanates posteriorly to the intervertebral foramen and travels distally for at least 3 vertebral segments except for the sacral nerve. It is not difficult to explain why patients with OVCF often have a combination of myalgic pain distal to the diseased vertebrae. In this study, local anesthetic ropivacaine was injected into the deep surface of the erector spinae and the transverse process (root above the transverse process) under G-arm X-ray machine positioning, which diffused into the paravertebral space and blocked the posterior branch of the spinal nerve, thus blocking the erector spinae and improving the patients’ myalgic pain[22, 23]. Certainly, according to the anatomy, the posterior branch of the spinal nerve blocked at the level of the diseased vertebra is actually the posterior branch of the spinal nerve that emanates downward from the level of the previous vertebra.However, this superior posterior branch of the spinal nerve is the one that primarily innervates the level of the diseased vertebra, hencethe block is consideredat the root above the transverse process of the diseased vertebra.
The drug for ESPB treatment is ropivacaine with the trade name of Nelapine, which is manufactured in 10 ml: 75 mg and concentration 0.75% by AstraZeneca AB. It is suitable for mixed nerves such as the posterior branch of the spinal nerve because of its high lipid solubility and anesthetic efficacy, as well as its strong separation effect on motor nerve block and sensory nerve block. Ropivacaine is also less toxic to the heart, so it is available for local blocks in elderly patients[24, 25]. The commonly used concentration of this drug is between 0.5% and 1.0% and the blockade of sensory nerves is about 3-5 hours, so that it is fast and long lasting in local analgesia. The maximum amount of the drug is 200 mg, namely 40 ml.The patients included in the trial were controlled to have no more than 2 spinal segments. For patients with 2 segments, 5 ml of ropivacaine was given to each side of the diseased vertebra, and the total amount was 20 ml, so it was safe and reliable.
There were no statistical differences in the preoperative VAS and ODI scores between the PVP+ESPB observation group and PVP control group, indicating that there were no significant differences in the condition of patients admitted to the hospital between the two groups. However, in the comparison of VAS and ODI scores at 2 hours after surgery and at hospital discharge, the observation group had lower scores than the control group which represented statistical differences, indicating that the patients in the observation group had better pain relief and more obvious improvement in lumbar activities after ESBP treatment, and ESPB had a significant effect of relieving erector spinae pain. According to the test results, there were statistical differences between the observation group and the control group in the early postoperative ambulation time and the early postoperative defecation (stool) time. It indicates that the patients in the observation group improved their pain symptoms earlier and faster with ESPB-assisted treatment, and patients were more active in early postoperative ambulation, promotion of bowel movement, and early postoperative defecation (stool), thus promoting early and rapid recovery of OVCF patients. According to the study results, there was no statistical difference between the two groups in terms of operative time, intraoperative bone cement filling volume, intraoperative blood loss, and surgery cost, etc. ESPB treatment was less invasive, and did not increase surgery time, intraoperative blood loss or surgery cost of patients when taking the control group into consideration. There was no statistical difference in the amount of intraoperative bone cement filling between the two groups, and no postoperative complications occurred in either group after surgery. According to the above results, ESPB did not increase the surgery time,operative risk or the financial burden of patients when compared with PVP, but diffuses the local anesthetic drug ropivacaine into the paravertebral space, blocks the posterior branch of the spinal nerve, further relieves the residual myalgic pain of OVCF patients and improves their pain symptoms, thus promoting their rapid recovery.
ESPB treatment was reported by Ferero et al. in 2016 and first applied in the analgesic treatment of thoracic neuropathic pain.ESPB is a newest technique of trunk nerve block with low risk, small trauma, and significant effect, which has been used in perioperative analgesia for thoracic surgery, breast surgery, and abdominal surgery. However, the application of ESPB in spine surgery is less reported.But with its advantages, it is believed that in the near future ESPB will be widely used not only in OVCF patients but also in other areas of spine surgery[26, 27]. In terms of the treatment of chronic pain in the chest, waist and back, for example, there are many patients with chronic pain in the chest, waist and backyetimageological examination often indicates no significant abnormalities in the chest, waist and back. The tension in the erector spinae muscle is found through physical examination with pain appearing under pressure. Recent studies have demonstrated that the posterior branch of the spinal nerve plays an important role in chronic pain of spinal origin, and ESPB directly blocks the posterior branch of the spinal nerve, thereby relieving the tension in the erector spinae muscle and relieving pain in the chest, waist and back. In terms of routine perioperative analgesia in spine surgery, lumbar spondylolisthesis, lumbar disc herniation, lumbar spinal stenosis, and thoracolumbar fractures are common in spine surgery and often require surgical treatment. Spine surgery is invasive and prolonged with more pronouncedpostoperative pain than general surgery. Deng Lin et al. have reported that for posterior lumbar surgery in spine surgery, the ultrasound-guided vertical spinal muscle block was performed in the T7 plane as an adjunct to general anesthesia. This report suggests that ESPB can provide postoperative analgesia, reduce the dosage of analgesic pump drugs and additional analgesics, and improve patient satisfaction with the postoperative analgesic effect. In the adjuvant treatment of patients with spinal tumors, the incidence of primary spinal tumors is low while metastatic spinal tumors account for more than 95% of cases, often involving the thoracic (70%) and lumbar spine(20%). Spinal tumors often have insidious onset, among which the primary lesion of spinal metastases are mostly breast cancer, prostate cancer, lung cancer, kidney cancer and thyroid cancer. Ueshima et al. performed ESPB in a patient with T8 tumor resection, and the sensory block plane was ideal to provide adequate analgesia for the patient. In terms of clinical treatment, when patients are found to have metastatic spinal tumors, their diseasesare often at an advanced stage. Patients are not strongly willing to accept spinal surgery and often choose radiotherapy and interventional therapy. However, for patients with metastatic spinal tumors, the cancer pain in the thoracolumbar back is often unresolved. With the advantages of local medication, low trauma and significant analgesic effect, ESPB can reduce cancer pain for patients with spinal tumors, especially those with metastatic spinal tumors. In terms of adjuvant anesthetic analgesia for patients who cannot tolerate general anesthesia for spinal incision infection, spinal surgery often features large wound surface, deep incision and long time with implants, and the risk of incisional infection is higher. Liu TZ et al. reported a case of vertical spinal plane block used for lumbar incisional debridement in a 75-year-old male patient who developed postoperative incisional infection. Considering the patient’s advanced age, obesity and long history of heavy smoking, a second general anesthesia in a short period of time may increase the incidence of perioperative anesthesia-related complications. Liu TZ et al. used ESPB for the first time in this patient to avoid the complications that may result from general anesthesia, and the operator successfully performed incisional debridement and achieved intraoperative and postoperative analgesia.
As a new nerve block technique, ESPBhas a superficial point of action and is far from important organs and blood vessels, contributing to a low risk of complications such as pneumothorax, hematoma, and nerve injury. ESPB has the advantages of high safety, simple operation, less toxic and side effects through localization and local application. ESPB not only has a significant adjunctive analgesic effect in patients undergoing percutaneous vertebroplasty, but also will exert a positively therapeuticeffect in other areas of spinal surgery.