Anterior cervical spine surgery is an effective and relatively safe method for treating degenerative diseases, trauma, tumors, inflammation and deformities of the cervical spine, but it is difficult, risky and prone to complications. Once complications occur in anterior cervical spine surgery, its management is often tricky and even causes serious consequences. Common complications include spinal cord injury, nerve injury, vascular injury, respiratory tract injury, esophageal injury, cerebrospinal fluid leak, epidural hematoma formation, and endophyseal failure. In recent years, anterior cervical spine surgery has been promoted and used in more and more hospitals in China. Many literature reports that its surgical efficacy is generally good, but surgical complications occur from time to time, thus affecting the surgical outcome. To date, Prof. Tiesheng Hou has personally performed more than 2500 anterior cervical surgeries with satisfactory results. This article highlights Professor Tiesheng Hou’s experience in the prevention and management of anterior cervical surgery complications and his domestic and international research progress.
I. Spinal cord injury
Anterior cervical spine surgery can cause or aggravate spinal cord injury. Although it is rare, it can cause serious consequences. The incidence is reported in the literature as 0.1%. Including primary injury and secondary injury. The former is a direct injury, such as improper use of surgical instruments to directly impact the spinal cord, injury to the spinal cord during separation and removal of compression, and displacement of bone graft to compress the spinal cord, which can cause different degrees of spinal cord injury. The latter is mostly a reperfusion injury. When the spinal cord is severely compressed and the blood supply is poor, the blood flow increases significantly within a short period of time after surgical decompression, which can cause congestion and swelling of the spinal cord, resulting in spinal cord dysfunction. No primary spinal cord injury occurred in this group, but there were three cases of postoperative spinal cord dysfunction of varying degrees, the reasons for which may be related to reperfusion injury, and the spinal cord function was satisfactorily restored after active non-surgical treatment. To prevent spinal cord injury, the intraoperative operation should be carefully regulated, and the bone graft should be embedded and fixed firmly; for those with severe spinal cord compression, high-dose methylprednisolone should be applied intraoperatively, and dexamethasone should be injected quietly for 3-5 days after surgery. In addition, it has been pointed out that intraoperative spinal cord function monitoring is of some value in preventing spinal cord injury. In terms of treatment, if there is a displaced bone graft compressing the spinal cord, the bone graft should be surgically explored and decompressed as soon as possible and re-fixed securely. Postoperative application of hormones, mannitol, neurotrophic agents and hyperbaric oxygen therapy play an important role in promoting the recovery of spinal cord function.
Second, nerve injury
During surgery, nerve injury can be caused by poor recognition of local anatomy, improper operation and balloon compression of the intralaryngeal tracheal tube. It mainly includes injury to the superior laryngeal nerve and injury to the recurrent laryngeal nerve. The incidence of the former is 0.3-3%, and the latter is 5-6.8%. Injury to the superior laryngeal nerve is mainly manifested as choking and coughing. Injury to one side of the recurrent laryngeal nerve is associated with hoarseness, while injury to both sides is associated with vocal cord paralysis and even asphyxia. The majority of cases are transient and do not require special treatment, recovering in a few weeks or months. The incidence of permanent vocal cord paralysis is about 0.3%. In our group, there were 2 cases of transient superior laryngeal nerve injury and 4 cases of transient recurrent laryngeal nerve injury, all of which recovered completely within 1-3 months after symptomatic treatment. It is very important to master the surgical operation, be familiar with the local anatomical relationship, not to blindly clamp and cut tissues when the visual field is not clear, and to avoid prolonged excessive pulling on the trachea and esophagus to prevent nerve injury. It has been reported in the literature that intermittent intraoperative deflation and inflation of the balloon of the intralaryngeal tracheal tube can reduce the incidence of laryngeal nerve injury from 6.8% to 1.7%. Currently, there is no satisfactory treatment for complete supraglottic and recurrent laryngeal nerve injury. In recent years, there are literature reports of laryngeal nerve exploration and repair at home and abroad, but the postoperative effect is not exact.
Third, vertebral artery injury
is less common, but once it occurs, it can cause catastrophic consequences. Burke reported that vertebral artery injury occurred in 6 cases (0.3%) of the 1976 anterior cervical surgeries. In our group, there was one case of intraoperative vertebral artery injury. The patient had a fifth cervical artery aneurysmal bone cyst. The left vertebral artery ruptured during intraoperative separation and resection of the tumor, resulting in hemorrhagic shock due to massive intraoperative bleeding. After massive blood transfusion and compression with local hemostatic gauze, a DSA was performed immediately after blood pressure stabilization to embolize the proximal end and then ligate the distal end. The postoperative recovery was good. The main causes of vertebral artery injury during anterior cervical spine surgery include.
1, anatomical variation and lesions of the vertebral artery. For example, the vertebral artery appears to be displaced inward in its travel position, compressed by bone flab, inflammatory infiltration, tumor erosion, etc.
2, improper operation during surgery, such as deviating from the midline or removing too much tissue structure to the side, inadvertent injury when separating and removing diseased tissue.
3.Operation error using high-speed grinding drill. Therefore, preoperative understanding of the anatomical structure of the vertebral artery and the relationship between the lesion and the vertebral artery, and intraoperative standardized operation is very important to prevent vertebral artery injury. If intraoperative vertebral artery injury occurs, local application of hemostatic gauze tamponade is the preferred first aid measure. Do not attempt to repair the vertebral artery, as it is quite difficult to do so. After local occlusion, if the blood pressure is stable, vertebral artery ligation is feasible, but a more prudent method is to immediately perform angiography (DSA) to embolize the injured vertebral artery.
IV. Airway injury
In anterior cervical surgery, prolonged overstretching can cause respiratory tract injury by compression and irritation, and its incidence is 1-7.3%. Respiratory tract injury is manifested as increased postoperative secretions, respiratory tract infection, and in severe cases, acute respiratory tract obstruction due to laryngeal edema, which can be life-threatening if not treated in time. Preoperative tracheal nudge training and intraoperative avoidance of excessive stretching are essential to prevent respiratory tract injury. The treatment includes postoperative ultrasonic nebulizer inhalation, hormones, dehydrating agents, expectorants, and antibiotics. For those who develop acute airway obstruction, ensure airway patency, such as sputum aspiration, oxygen administration, and tracheotomy if necessary. In this group, there were 12 cases with respiratory tract injury, among which 3 cases had acute respiratory obstruction. After the above treatment methods, the respiratory function was restored to normal.
V. Esophageal injury
During anterior cervical surgery, improper placement of the pulling hook, prolonged pulling of the esophagus or accidental injury to the esophagus can cause esophageal injury and esophageal fistula, which is a serious complication. The incidence is 0-4%. There was no esophageal injury in this group. For small esophageal fistulas, they can generally heal within 2-3 weeks after fasting, gastrointestinal decompression, nasal feeding and anti-infection treatment. However, for severe esophageal fistulas, because they are often combined with malnutrition and other systemic complications, treatment is difficult and requires surgery to remove necrotic tissue and repair the fistula.
Cerebrospinal fluid leak
During surgery, the dura mater may be broken and cerebrospinal fluid leakage may occur during the separation and removal of the pressure-causing material. The incidence is 2.31-9.37%. Once cerebrospinal fluid leakage occurs, it can lead to incisional infection, septic meningitis, and even life-threatening. Therefore, the operation should be performed carefully to avoid damaging the dura mater as much as possible. Due to the small operating space, direct suturing of the dura mater cannot be performed after the dural rupture. In our group, there were 12 cases of intraoperative dural rupture. They were treated with subcutaneous fascia and gelatin sponge blocking and caulking, and postoperative drainage and anti-infection treatment were performed, and excellent results were obtained.
VII. Epidural hematoma formation
Postoperative epidural hematoma formation can cause spinal cord compression and different degrees of spinal cord dysfunction. In severe cases, it can lead to paraplegia, and its incidence is 0.1-0.3%. The main measures to prevent postoperative epidural hematoma include.
1, for the preoperative existence of liver function abnormalities, poor coagulation mechanism should not be operated, should first internal medicine treatment.
2, intraoperative hemostasis should be complete, if necessary, the bone wax to seal the oozing blood on the bone surface and bipolar electrocoagulation to perform complete hemostasis in the decompression zone. Professor Tiesheng Hou used a rice-sized gelatin sponge filling with bioprotein gel to achieve complete hemostasis in the decompression zone. The postoperative period (especially within 24 h after surgery) should be closely monitored for changes in the condition. Once the symptoms of hematoma compression appear, they should be actively treated. If surgical exploration can be performed in time to remove the hematoma, good results can be obtained in most cases. In this group, there were 4 cases of epidural hematoma, 3 of which occurred within 24 h after surgery and 1 case occurred 12 d after surgery, and the spinal cord function recovered well after timely surgical exploration and hematoma removal.
VIII. Failure of endoprosthesis
Internal fixation of the plate system while performing anterior cervical decompression and bone grafting is a common method for the treatment of cervical spine injuries. A large number of clinical application studies have confirmed that the anterior cervical internal fixation system has the advantages of providing immediate stability, firmly fixing the bone graft, promoting the fusion of bone graft, and enabling the patient to move around early after surgery, but it can also occur such as plate displacement, screw loosening and fracture, resulting in the failure of the internal implant. The reasons are mainly related to improper surgical operation, poor quality of endograft and improper postoperative protection. Therefore, proper selection and placement of endograft, ensuring the standard requirements of internal fixation, and proper postoperative protection are the key measures to prevent endograft failure. In this group, there were 3 cases of screw fracture, 2 cases of screw loosening and plate displacement. For the broken screws, the endoprosthesis was removed. In the case of screw loosening and plate displacement, no surgery was performed because they occurred after the bone graft healed and there were no symptoms such as esophageal compression. They have been followed up for 3-6 years and no adverse effects were observed.