Abnormal types of intervertebral disc structure and related mechanical loading with biomechanical factors / 中国组织工程研究

BACKGROUND:The problem of intervertebral disc injury and degeneration has been studied in many ways.Many studies have shown that intervertebral disc injury and degeneration is driven by mechanical loading factors.However,the potential relationship between common phenotypes of intervertebral disc injury and degeneration and mechanical loading factors has been rarely summarized. OBJECTIVE:To summarize the types of common structural abnormalities exhibited by intervertebral disc injury and degeneration in the published literature,and sum up the potential links to the types of mechanical loading that lead to these structural abnormalities in in vitro and ex vivo experimental studies. METHODS:Using the terms"intervertebral disc failure,intervertebral disc injury,mechanical load,mechanical factor,load factor,biomechanics"as Chinese and English key words in PubMed,CNKI,and WanFang databases,articles related to intervertebral disc injury degeneration and mechanical load factors were retrieved.Literature screening was performed according to the inclusion and exclusion criteria,and 88 articles were finally included. RESULTS AND CONCLUSION:(1)Common structural abnormalities of intervertebral discs include decreased intervertebral disc height,disc bulge,osteophyte formation,annulus fibrosus tear,intervertebral disc herniation or disc prolapse,endplate damage,Schmorl nodes and intervertebral disc calcification.Intervertebral discs are susceptible to mechanical load types such as compression,bending,axial rotation,and compound loads.(2)The compressive load mainly causes the decrease of the proteoglycan content and the water-binding ability of the intervertebral disc,leading to the decrease or swelling of the intervertebral disc and further damage and degeneration of the intervertebral disc.In addition,the excessive compressive load causes greater damage to the endplate.(3)Bending load and axial rotation load damage the annulus fibrosus more than the endplate,and prolonged or repeated bending loads can cause tearing of the fibrous annulus and herniation or prolapse of the intervertebral disc,while pure axial rotation loads can induce less damage to the intervertebral disc and only cause the tear of the annulus fibrosus.(4)However,when different load types act in combination,it is more likely to result in high stress on the disc and a greater risk of disc injury.(5)Injury and degeneration of the intervertebral disc present progressive structural damage,and early prevention and protection are particularly important in clinical practice.Future tissue engineering research can start with early repair of the intervertebral disc.

A surgical management of articular disc injury in temporomandibular Joint: A compiled case series of two cases with articular disc tear managed with surgical intervention

Articular disc injury in the temporomandibular joint (TMJ) can lead to significant pain and limited jaw movement. We present two cases in this case series of articular disc injuries in the TMJ and elaborate on their etiology, clinical presentation, diagnostic modalities, and treatment provided with follow-up reviews. Case 1 involved a 50-year-old female with a history of pain and clicking in the left TMJ for 10 years, wherein imaging studies revealed a discal tear. Case 2 involved a patient who presented with trauma and was diagnosed with a displaced disc with a disc tear when the patient was screened for mandibular fractures. The patients underwent surgical intervention, and the disc tear was repaired, following which both showed marked improvement. Our cases highlight the importance of early diagnosis and necessary surgical management of articular disc injury in the TMJ for better clinical outcomes.

Herniation of intervertebral disc into thoracolumbar fracture vertebral body leads to malunion of fracture and decrease of intervertebral space height / 中国骨伤

OBJECTIVE@#To analyze the clinical characteristics of intervertebral disc tissue injury and herniation into the vertebral body in thoracolumbar fracture on fracture healing, vertebral bone defect volume and intervertebral space height.@*METHODS@#From April 2016 to April 2020, a total of 140 patients with thoracolumbar single vertebral fracture combined with upper intervertebral disc injury treated with pedicle screw rod system reduction and internal fixation in our hospital. There were 83 males and 57 females, aged from 19 to 58 years old, with an average age of (39.33±10.26) years old. All patients were followed up regularly 6 months, 12 months and 18 months after surgery. The patients with injured intervertebral disc tissue not herniated into the fractured vertebral body were the control group, and the patients with injured intervertebral disc and herniated into the fractured vertebral body were the observation group. By detecting the thoracolumbar AP and lateral X-ray films, CT and MRI of the thoracolumbar segment at different follow-up time, calculate the changes of the wedge angle of the fractured vertebral body, the sagittal kyphosis angle and the height of the superior adjacent intervertebral space, the changes of the fracture healing and bone defect volume after the reduction of the vertebral body, and the changes of the intervertebral disc degeneration grade. The prognosis was evaluated by visual analogue scale(VAS) and Oswestry disability index(ODI). Finally, the differences of the above results among different groups were comprehensively analyzed.@*RESULTS@#All the patients had normal wound healing without complications. A total of 87 patients received complete follow-up data, at least 18 months after internal fixation. Thoracolumbar AP and lateral X-ray films showed that 18 months after the reduction and internal fixation operation, the vertebral wedge angle, sagittal kyphosis angle and the height of the upper adjacent intervertebral space in the observation group were greater than those in the control group(P<0.05). CT scanning showed that the deformity of the fracture healed 12 months after the vertebral body reduction in the observation group and formed a "cavity" of bone defect connected with the intervertebral space, and its volume was significantly increased compared with that before (P<0.05). MRI scanning showed that the degeneration rate of injured intervertebral discs in the observation group was more serious than that in the control group 12 months after operation(P<0.05). However, there was no significant difference in VAS and ODI score at each time.@*CONCLUSION@#Herniation of injured intervertebral disc tissue hernias into the fractured vertebral body leads to increased bone resorption defect volume around the fracture and forms a malunion "cavity" connected with the intervertebral space. This may be the main reason for the change of vertebral wedge angle, the increase of sagittal kyphosis angle and the decrease of intervertebral space height after removal of internal fixation devices.

Application of modified minimally invasive lateral interbody fusion in anterior support and reconstruction for thoracolumbar fracture combined with intervertebral disc injury / 中华创伤杂志

Objective@#To investigate the preliminary clinical efficacy of modified minimally invasive lateral interbody fusion in the anterior support and reconstruction for thoracolumbar fracture combined with intervertebral disc injury.@*Methods@#A retrospective case series study was conducted to analyze the clinical data of 14 patients with single-segment thoracolumbar fracture combined with intervertebral disc injury admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine from December 2017 to May 2018. There were 12 males and two females, aged 22-56 years [(37.4±10.2)years]. The injured segments were at L1 in nine patients and L2 in five patients. Twelve patients had upper disc injury and two patients had lower disc injury. Before operation, American Spinal Injury Association (ASIA) classification was grade A in five patients, grade B in four, grade C in three, and grade D in two. All patients received modified minimally invasive lateral interbody fusion to reconstruct the stability of the anterior and middle columns of the spine one week after posterior short-segment fixation. The operation time, intraoperative bleeding, postoperative hospital stay and complications were recorded. Pain visual analogue scale (VAS) and ASIA nerve injury grading were used to evaluate the clinical efficacy. The Cobb angle changes of the operative segment and lumbar lordosis were compared before operation and during the last follow-up.@*Results@#The patients were followed up for 6-14 months[(12.1±3.6)months]. The operation time was 65-210 minutes [(138.9±39.4)minutes], and the intraoperative blood loss was 250-600 ml [(407.1±119.1)ml], respectively. The total postoperative length of stay ranged from 3 to 13 days [(7.8±2.5)days]. The incisions healed well at stage I in all patients. VAS for back pain and leg pain before operation were (6.3±2 .4)points and (4.1±1.3)points respectively. The final VAS for back pain and leg pain were (2.2±0.6)points and (2.3±0.8)points, which were significantly lower than the preoperative VAS (both P<0.01). At the last follow-up, there was one patient with grade A, two with grade B, five with grade C, one with grade D, and five with grade E. Postoperative CT showed that decompression was complete, implants were in good position and internal fixation was reliable. Preoperative Cobb angles of lumbar lordosis and the injury segment were (-7.8±3.9)° and (24.8±6.9)° respectively. The final Cobb angles of lumbar lordosis and the injury segment were (3.1±2.7)° and (30.7±9.6)°, which were significantly restored compared with preoperative values (both P<0.01). One patient had postoperative pain in the front thigh, and another patient had numbness in the front thigh, whose symptoms were alleviated after non-surgical treatment. No serious surgical complications such as quadriceps femoris and weakness, pleural tear, vascular injury, nerve root injury, sympathetic nerve injury, retroperitoneal hematoma and artificial vertebral body displacement occurred in these patients.@*Conclusions@#For anterior reconstruction of the thoracolumbar fracture with intervertebral disc injury, the modified minimally invasive lateral interbody fusion has the advantages of less invasive, less blood loss, shorter hospitalization time, low incidence of complications. Significant pain relief, neurological function improvement, and anterior and middle column reconstruction can be achieved postoperatively.

Application of modified minimally invasive lateral interbody fusion in anterior support and reconstruction for thoracolumbar fracture combined with intervertebral disc injury / 中华创伤杂志

Objective To investigate the preliminary clinical efficacy of modified minimally invasive lateral interbody fusion in the anterior support and reconstruction for thoracolumbar fracture combined with intervertebral disc injury. Methods A retrospective case series study was conducted to analyze the clinical data of 14 patients with single-segment thoracolumbar fracture combined with intervertebral disc injury admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine from December 2017 to May 2018. There were 12 males and two females, aged 22-56 years [(37. 4 ± 10. 2)years]. The injured segments were at L1 in nine patients and L2 in five patients. Twelve patients had upper disc injury and two patients had lower disc injury. Before operation, American Spinal Injury Association ( ASIA) classification was grade A in five patients, grade B in four, grade C in three, and grade D in two. All patients received modified minimally invasive lateral interbody fusion to reconstruct the stability of the anterior and middle columns of the spine one week after posterior short-segment fixation. The operation time, intraoperative bleeding, postoperative hospital stay and complications were recorded. Pain visual analogue scale ( VAS) and ASIA nerve injury grading were used to evaluate the clinical efficacy. The Cobb angle changes of the operative segment and lumbar lordosis were compared before operation and during the last follow-up. Results The patients were followed up for 6-14 months[(12.1 ±3.6)months]. The operation time was 65-210 minutes [(138.9 ±39.4)minutes],and the intraoperative blood loss was 250-600 ml [(407. 1 ± 119. 1) ml], respectively. The total postoperative length of stay ranged from 3 to 13 days [(7. 8 ± 2. 5)days]. The incisions healed well at stage I in all patients. VAS for back pain and leg pain before operation were (6. 3 ± 2 . 4)points and (4. 1 ± 1. 3) points respectively. The final VAS for back pain and leg pain were (2. 2 ± 0. 6)points and (2. 3 ± 0. 8)points, which were significantly lower than the preoperative VAS (both P<0. 01). At the last follow-up, there was one patient with grade A, two with grade B, five with grade C, one with grade D, and five with grade E. Postoperative CT showed that decompression was complete, implants were in good position and internal fixation was reliable. Preoperative Cobb angles of lumbar lordosis and the injury segment were ( -7. 8 ± 3. 9)° and (24. 8 ± 6. 9)° respectively. The final Cobb angles of lumbar lordosis and the injury segment were (3. 1 ± 2. 7)° and (30. 7 ± 9. 6)°, which were significantly restored compared with preoperative values (both P<0. 01). One patient had postoperative pain in the front thigh, and another patient had numbness in the front thigh, whose symptoms were alleviated after non-surgical treatment. No serious surgical complications such as quadriceps femoris and weakness, pleural tear, vascular injury, nerve root injury, sympathetic nerve injury, retroperitoneal hematoma and artificial vertebral body displacement occurred in these patients. Conclusions For anterior reconstruction of the thoracolumbar fracture with intervertebral disc injury, the modified minimally invasive lateral interbody fusion has the advantages of less invasive, less blood loss, shorter hospitalization time, low incidence of complications. Significant pain relief, neurological function improvement, and anterior and middle column reconstruction can be achieved postoperatively.