Rib fractures occur in up to 85% of closed chest trauma, and the common causes of injury include road traffic injuries, fall from height injuries, indirect crush injuries, and direct violence injuries. Clinically, it is divided into single or multiple rib fractures and multiple rib fractures, and shackle thorax is one of the special types, i.e., multiple fractures of three or more consecutive ribs. According to statistics, the incidence of shackle thorax accounts for about 10%-15% of blunt chest wall injuries, with an overall mortality rate of 16%-20% [1]. The current treatment for rib fractures is divided into conservative treatment and surgical treatment. The choice of treatment for rib fractures is still controversial, and most scholars believe that fracture ends displaced <2 cm can be healed by conservative treatment, which is also mostly implemented in clinical practice. Conservative treatment includes controlled rehydration, analgesia, appropriate external fixation, and ventilator-assisted breathing, and is briefly described below. 1.1 Analgesia Rib fractures are painful and can increase the probability of pulmonary infection and affect respiratory function and fracture recovery, especially in patients with shackled chest. In general, analgesia should be provided for all rib fractures because adequate analgesia can significantly reduce complications and improve prognosis. Commonly used analgesic methods include oral analgesics, intercostal nerve blocks, intravenous maintenance analgesia, and continuous epidural analgesia. It has also been reported [2] that interpleural or epidural analgesia is used to treat multiple rib fractures, and continuous epidural analgesia has now been used as a routine analgesic method for multiple rib fractures in many foreign hospitals. In recent years, subcutaneous electrical stimulation analgesia and continuous thoracic paravertebral block analgesia have also been used clinically, among which subcutaneous electrical stimulation analgesia is mostly used for rib fractures with relatively mild symptoms. Recently, Davies et al [3] reported that the analgesic effect of continuous thoracic paravertebral block was similar to that of continuous epidural analgesia, but the complications such as pain relief failure, hypotension, vomiting and urinary retention were significantly lower than the latter. 1.2 External chest wall fixation External chest wall fixation for multiple rib fractures or shackled chest can reduce pain, correct paradoxical breathing, and significantly improve the patient's respiratory function after external fixation, and no significant deformity of the chest wall remains after healing. The former traditional methods include wide tape pulling and fixation, multi-headed chest strap wrapping and fixation, sandbag compression wrapping, etc. This method makes the chest wall in the softened area invaginate, which increases the compression on the lung and easily leads to pulmonary atelectasis and pneumonia, and the rib fracture severed end is easy to damage the intercostal vessels and lung tissue, so it can only be used as temporary emergency treatment or fixation for patients with light fractures. The main indications for the latter are obvious paradoxical respiratory movements of the chest wall but not combined with serious organ damage, temporary fixation failure, etc. External chest wall fixation is the main treatment method for the treatment of shackled chest and correction of paradoxical respiration, and there are four basic forms: (1) scarf clamp gravity suspension traction method: the most classic method; (2) chest wall external fixation traction frame method: the principle is to use the normal part of the chest wall as support for external fixation traction of fractured ribs, which can be used for anterior and lateral wall rib fractures; (3) plexiglass chest wall external fixation method: the main principle is to place a porous plexiglass plate on the chest wall to fix the fracture. (3) Plexiglas chest wall external fixation method: the main principle is to shape a porous Plexiglas plate at high temperature to fit the patient's thorax and fix the fractured ribs on the porous Plexiglas plate with wires to fix multiple rib fractures; (4) subcutaneous rib fracture support method: the main principle is to pierce subcutaneous kerf pins on at least 1 unfractured rib above and below the fractured ribs to fix the fractured ribs on the unfractured ribs to achieve fixation of the chest wall and eliminate paradoxical breathing The purpose is to fix the chest wall and eliminate abnormal breathing. When performing external fixation traction, scarf clamp or wire fixation should be performed carefully to avoid damage to intercostal nerves, blood vessels, and lungs. Mechanical ventilation can significantly improve hypoxemia, correct paradoxical breathing, and treat pulmonary atelectasis, and has been used as standard treatment for multiple rib fractures in some foreign hospitals. Its indications are rib fractures ≥8, combined with severe pulmonary contusion, craniocerebral injury, etc., and wet oxygenation cannot ensure ventilation and oxygenation, with specific indices of tidal volume <5 ml/kg, respiratory rate >35 breaths/min, PCO2 >55 mmHg, and arterial oxygen saturation <90%. Conventional mechanical ventilation, noninvasive mask ventilation, continuous positive airway pressure ventilation (CPAP), intermittent positive airway pressure ventilation (IPAP), etc., have been reported [4] to apply noninvasive external continuous negative pressure ventilation (CNEP) for the treatment of continuous shackle chest. In recent years, other authors have applied liquid ventilation [including total liquid (TLV) and partial liquid (PLV) ventilation, of which PLV is more commonly used] for the treatment of pulmonary contusion/acute respiratory distress syndrome (ARDS), and although the efficacy is still under debate, it provides a new option for the treatment of acute lung injury (ALI)/ARDS, with a current preference for PLV in combination with other techniques [5]. Short-term complications of mechanical ventilation include pneumothorax, hypoxemia before onset of action, hypotension in the body circulation, arrhythmias, etc. Long-term application may increase the probability of pulmonary infection and sepsis, difficulties in deconditioning, etc. Therefore, the indications should be strictly controlled. 2 Surgical treatment The choice of treatment modality for rib fractures in clinical practice is relatively well accepted, mainly based on the following understanding: (1) dislocation of the fracture end without repositioning may cause deformed healing of the fracture, thus affecting aesthetics and even respiratory function; (2) multiple rib fractures without fixation often lead to pulmonary infection due to poor analgesia and fear of coughing; (3) patients requiring ventilator maintenance without timely fixation can lead to an increased incidence of ventilator-associated pneumonia and may also encounter a range of problems such as difficulty in deconditioning. In a recent foreign randomized controlled study, 37 cases of multiple multiple rib fractures were randomly divided into 2 groups (18 cases in the Judet fixator group and 19 cases in the non-operative group), and the duration of mechanical ventilation, duration of ICU monitoring, and incidence of pneumonia were (10.8±3.4) days, (16.5±7.4) days, and 24%, respectively, in the final operative group after treatment, which were significantly less than those in the non-operative group ( 18.3±7.4) days, (26.8±13.2) days, and 77% (P<0.05); and the maximum spirometry was significantly higher in the surgical group, of which 11 cases were able to work normally, compared with only one case in the non-surgical group [6]. In another randomized controlled study, the chest wall stabilization rate was 85% (17/20) in the group with surgical (kerfing, stainless steel plate fixation, or combination) internal fixation of rib fractures, which was significantly higher than 50% (10/20) in the non-surgical group; 45% (9/20) of the surgical group required mechanical ventilation with a mean duration of 2 days, compared with 35% of patients in the non-surgical group, with a mean duration of 12 days; and the probability of chest wall deformity and restrictive respiratory insufficiency was significantly lower in the surgical group than in the control group [7]. Therefore, an increasing number of scholars believe that early surgical fixation of the ribs is highly necessary. The indications for surgical internal fixation treatment are (1) multiple rib fracture collapse in the thorax causing significant deformity and formation of paradoxical conjoined breathing, but not accompanied by severe pulmonary contusion; (2) particularly significant displacement of the fracture end or multi-segment, comminuted rib fracture with the possibility of neurovascular injury, where conservative treatment will deformity healing affecting respiratory function; (3) simple rib with intractable pain in the chest wall with respiratory distress and hemopneumothorax fracture; (4) the need for open-chest exploration or other surgical procedures at the same time feasible rib fixation; (5) non-invasive mechanical ventilation treatment is poor or difficult to get off the machine; (6) young patients with high aesthetic requirements and economic conditions allow, etc. There are many surgical fixation devices and methods for rib fractures, but not many of them are really classical or have been proven to be reliable and effective by a large number of clinical trials. Most orthopedic alloy titanium plates have greater bending strength than ribs and are more biocompatible, so they are widely used. (1) AO plate: the most commonly used fixation instruments abroad are 3.5mm pelvic reconstruction shaped plate, micro titanium plate, U-shaped plate, etc. Some experiments [8] applied 3.5mm thick pelvic reconstruction shaped steel plate with 2.4mm thick mandibular shaped steel plate and 1.0mm dental steel plate to fix rib fracture and found that the pelvic reconstruction shaped steel plate can firmly fix the fracture end due to the maximum bending strength, but it can cause postoperative chest pain and require secondary surgery to remove; in addition, the thick steel plate fixation has the possibility of screw loosening; mandibular shaped The mandibular plastic plate and dental plate can use locking nails at the head end, so the periosteum of the fixed rib can be kept almost intact, especially the mandibular plastic plate fixation group. However, the flexural strength of the dental plate is lower than that of the rib itself, which may cause poor fixation. Some experiments [9] proved that the U-shaped steel plate has stronger bending resistance than the standard steel plate, and is much smaller than the conventional plate internal fixator, with relatively small surgical incision and trauma, which has great application prospects in the future. (2) Special fixators such as Judet, Vecsei, Labitzke, Rehm, Sanchez fixators: these fixators do not require screw fixation, and the fixation method is simpler and does not injure the bone marrow cavity. For simple fractures with both ends intact, especially oblique fractures, the Judet fixator is used; for comminuted rib fractures or chest wall integrity disruptions, the Sanchez fixator is used. However, the biomechanical strength of these fixators is not high, and there is a risk of unstable healing of the fracture. (3) Titanium-nickel alloy memory ring hugger: there are more clinical applications reported in China [10], the nickel-titanium memory alloy ring hugger can be deformed and unfolded at low temperature, and automatically return to its original shape at body temperature, which makes fracture fixation simple and convenient. Its advantages are that it reduces the operation time, can be used for internal fixation of rib fractures in emergency situations, and reduces the adverse effects of surgery itself on patients; it has good histocompatibility and can be used at multiple points around the ribs together to produce a ring hugging force, and the fracture end is not easily rotated and displaced after surgery; however, the material is more expensive and not easy to remove. In summary, the current splint is widely used and has good fixation effect, but it is difficult to fix rib fractures located in the back [8] and cannot firmly fix fractures of combined rib cartilage, and splints of non-degradable materials can cause discomfort or chronic postoperative intercostal nerve pain in patients, which need to be removed by secondary surgery. 2.2 Intramedullary fixation instruments Commonly used instruments include Kirschner steel pins, Rush intramedullary pins or Jergesen rods, Rehbein plates, etc. The advantage of these instruments is that the incision is relatively small. The advantages are that the incision is relatively small and easy to remove, and there is no need to peel off too much periosteum, so the surgical trauma is relatively small; the disadvantage is that there may be rotational displacement of the broken end of the rib and the displacement of the pin itself, which may lead to deformed fracture healing or bone nonunion. Intramedullary fixation devices can be used in combination with other methods to achieve a more satisfactory fixation effect, and the use of intramedullary fixation devices in combination with an osteotome for the treatment of combined rib cartilage fractures has been reported [11]. 2.3 Vertical fixation method For multiple multiple rib fractures, internal fixation devices are usually fixed in the upper rib of the first fractured rib and the lower rib of the last fractured rib, perpendicular to the long axis of the rib. Commonly used instruments include kerf pins, bone cement prostheses, and rib spacers. The disadvantage of this method is that the fixed rib space cannot be widened with respiratory movements, which affects the recovery of pulmonary function after surgery to a certain extent, and it cannot be used for fixation of rib fractures in minor patients because it can affect the growth and development of the patient's thorax. Recently, it has been reported [12] that an extensible rib vertical fixator is expected to be used for rib fracture fixation in pediatric and immature patients. 2.4 Others Steel wire and silk wire are rarely used alone due to their poor stability and are mostly used in combination with other methods or applied to rib fractures in animals. 2.5 Biodegradable material plates or intramedullary nails A few cases have been reported at home and abroad using plates and screws made of poly-biodegradable materials - 70:30 poly (LlactidecoD, Llactide) [13], 82:18 poly (levulinic acid, glycolic acid) [14] for rib The latter can be shaped at high temperature; biodegradable poly-L-lactide intramedullary nails [15] have also been used in clinical practice. At present, the application of biodegradable materials is still under clinical exploration, and its fixation effect and postoperative recovery effect still need large-scale clinical observation, and its main development direction is the design of minimally invasive instruments and improvement of surgical methods to minimize the damage of the operation itself. Fixation of the 4th to 10th ribs is sufficient for multiple rib fractures, as the 1st to 3rd ribs are close to the subclavian artery, while the 11th and 12th rib fractures have little effect on paradoxical breathing. In the case of continuous shackle chest, fixation of several ribs in the focal area is sufficient to correct the paradoxical respiratory motion, and there is no need to fix all of them to reduce surgical trauma. In addition to the conventional incision along the fracture line, some authors have developed an approach via the "auditory triangle" for internal fixation of the focal point of the shackled chest, which achieves a minimally invasive incision and reduces surgical injury. Thoracoscopy can play an auxiliary role for external fixation of the chest wall, and it can also be used for hemostasis, removal of free bones and lung repair under direct vision, which is an important development direction for minimally invasive treatment of multiple rib fractures or shackle thorax. It should be noted that if the patient has severe pulmonary contusion in combination, the surgery should be postponed until the pulmonary contusion improves, because patients with severe pulmonary contusion do not benefit much from surgery [16]. 3 Tissue engineering treatment In recent years, artificial biomaterials have been used to construct the defective chest wall at home and abroad, and the commonly used materials include Prolene mesh, methyl methacrylate, Marlex mesh, Vicryl mesh, polytetrafluoroethylene, polypropylene, etc. [17]. It has been reported [18] that artificial biomaterials can be used for early fixation of multiple rib fractures or hypophyseal thorax, which are easier to implant and remove. Biodegradable material tissue engineering technology is still in the animal experimental stage [19], but good progress has been made, and it is believed that with the development of tissue engineering technology, it is expected to provide new materials and methods for the treatment of multiple rib fractures or shackle thorax. In conclusion, the incidence of rib fractures is high and most patients can be cured by conservative treatment, but clinical trials have shown that selective internal rib fixation is more beneficial to patient recovery. Synthetic biodegradable materials can be implanted without secondary surgical removal, which can reduce surgical trauma and complications such as postoperative chest pain, and are currently used clinically; the development of modern tissue engineering technology also provides new treatment directions for large rib fractures. Comprehensive treatment of rib fracture, according to the indications of various treatment methods and combined with the actual patient to choose the appropriate treatment plan, can be expected to further improve the efficacy of the treatment of rib fracture, especially the shackled chest.