Increasing the angle between caudal screw and the transverse plane may aggravate the risk of femoral head necrosis by deteriorating the fixation stability in patients with femoral neck fracture.

Necrosis of the femoral head is the main complication in femoral neck fracture patients with triangle cannulated screw fixation. Instant postoperative fixation instability is a main reason for the higher risk of femoral head necrosis. Biomechanical studies have shown that cross screw fixation can effectively optimize fixation stability in patients with proximal humerus fractures and pedicle screw fixation, but whether this method can also effectively optimize the fixation stability of femoral neck fractures and reduce the corresponding risk of femoral head necrosis has yet to be identified. In this study, a retrospective review of imaging data in femoral neck fracture patients was performed. The cross angle between the femoral neck and the caudal cannulated screw was reported; if the angle between the screw and the transverse plane increased, it was recorded as positive; otherwise, it was recorded as negative. Angle values and their corresponding absolute values were compared in patients with and without femoral head necrosis. Regression analysis identified potential risk factors for femoral head necrosis. Moreover, the biomechanical effect of the screw-femoral neck angle on fixation stability was also verified by numerical mechanical simulations. Clinical review presented significantly larger positive angle values in patients with femoral head necrosis, which was also proven to be an independent risk factor for this complication. Moreover, fixation stability progressively deteriorated with increasing angle between the caudal screw and the transverse plane. Therefore, increasing the angle between the caudal screw and the transverse plane may aggravate the risk of femoral head necrosis by deteriorating the fixation stability in patients with femoral neck fracture.

Nucleus high intensity in the T2-weighted MRI is a potential predictor of annulus tear in cervical injured patients: a case comparative study.

BACKGROUND: Segmental fusion operations assume paramount significance for individuals afflicted by full layers of annulus tears as they avert the perils of rapid disc degeneration and segmental instability. Structures with high signal intensity in the T2-weighted MRI can predict potential damage to the injured segment. Since local structures are shortly related biomechanically, this may be an effective predictor for annulus tears. METHODS: A retrospective analysis of the clinical data of 57 patients afflicted by cervical injuries and subjected to single-segment ACDF has been performed in this study. The surgeon performed intraoperative exploration to assess the integration status of the annulus. The signal intensity of the prevertebral space, nucleus, and injured vertebral bodies were judged in the T2-weighted imaging data. Regression analyses identified independent predictors for annulus tears, and the area under the receiver operating characteristic curve (AUC) was computed to evaluate the predictive performance of potential independent predictors. RESULTS: The occurrence of nucleus high intensity was significantly higher among individuals with annulus tears, and the nucleus high intensity was deemed an independent predictor for determining the presence of intraoperative visible annulus tears in patients with cervical injuries. AUC for nucleus high intensity was calculated as 0.717, with a corresponding p-value less than 0.05. CONCLUSIONS: In the realm of diagnosing annulus tears in injured cervical patients, nucleus high intensity in the T2-weighted MRI emerges as a promising predictive factor. Notably, this applies specifically to patients devoid of fracture and visible annulus tears in their MRI scans. Such positive outcomes should be regarded as prospective indications for ACDF.

[The effect of axis pedicle and intra-axial vertebral artery on C 2 pedicle screw placement].

Objective: To investigate the influence of axis pedicle and intra-axial vertebral artery (IAVA) alignment on C 2 pedicle screw placement by measuring the data of head and neck CT angiography. Methods: The axis pedicle diameter (D), isthmus height (H), isthmus thickness (T), and IAVA alignment types were measured in 116 patients (232 sides) who underwent head and neck CT angiography examinations between January 2020 and June 2020. Defined the IAVA offset direction by referencing the vertical line through the center of C 3 transverse foramen on the coronal scan, it was divided into lateral (L), neutral (N), and medial (M). Defined the IAVA high-riding degree by referencing the horizontal line through the outlet of the C 2 transverse foramen, it was divided into below (B), within (W), and above (A). The rate of pedicle stenosis, high-riding vertebral artery, and different IAVA types were calculated, and their relationships were analysed. Simulative C 2 pedicle screws were implanted by Mimics 19.0 software, and the interrelation among the rates of pedicle stenosis, high-riding vertebral artery, IAVA types, and vertebral artery injury were analyzed. Results: The rate of C 2 pedicle stenosis was 33.6% (78/232), and the rate of high-riding vertebral artery was 35.3% (82/232). According to the offset direction and the degree of riding, IAVA was divided into 9 types, among which the N-W type (29.3%) was the most, followed by the L-W type (19.0%) and the L-B type (12.9%), accounting for 60.9%. The vertebral artery injury rate of simulative implanted C 2 pedicle screws was 35.3% (82/232). The vertebral artery injury rate in patients with pedicle stenosis and high-riding vertebral artery was significantly higher than that who were not ( P<0.001). The rate of pedicle stenosis, high-riding vertebral artery, and vertebral artery injury were significantly different among IAVA types ( P<0.001), and M-A type was the most common. Conclusion: Vertebral artery injury is more common in pedicle stenosis and/or high-riding vertebral artery and/or IAVA M-A type. Preoperative head and neck CT angiography examination has clinical guiding significance.

[Comparative study on the effectiveness of improved and traditional Kirschner wire tension band fixation in treatment of type C patellar fractures].

OBJECTIVE: To compare the effectiveness of improved and traditional Kirschner wire tension band fixation in treatment of type C patellar fractures. METHODS: Between January 2017 and January 2019, 26 patients with type C patellar fractures were treated with improved Kirschner wire tension band fixation (group A), and 24 patients were treated with traditional Kirschner wire tension band fixation (group B). There was no significant difference in gender, age, injury cause, disease duration, and side and type of fracture between 2 groups ( P>0.05). The operation time, intraoperative blood loss, the visual analogue scale (VAS) scores at 1 and 3 days after operation, the fracture healing time, and the occurrence of complications (skin irritation of Kirschner wires, failure of internal fixation, fracture reduction loss) were recorded, and the knee function was evaluated by Lysholm scoring standard in 2 groups. RESULTS: The operation time in group A was significantly less than that in group B ( t=-4.742, P=0.000). There was no significant difference in the intraoperative blood loss and VAS scores at 1 and 3 days after operation between 2 groups ( P>0.05). All incisions healed by first intention. All patients were followed up 8-15 months, with an average of 11 months. The fracture healing time was (3.3±0.6) months in group A and (3.2±0.6) months in group B, showing no significant difference ( t=0.589, P=0.559). At last follow-up, the knee joint function was evaluated according to Lysholm scoring standard. And there were 15 cases of excellent, 8 cases of good, and 3 cases of fair, with an excellent and good rate of 88.5% in group A; there were 8 cases of excellent, 7 cases of good, 7 cases of fair, and 2 cases of poor, with an excellent and good rate was 62.5%. The difference between 2 groups was significant ( Z=2.828, P=0.005). The internal fixators were removed after the fracture healed in 2 groups. At last follow-up, no skin irritation of Kirschner wires occurred in group A, but 3 cases in group B. X-ray films reexamination showed that 5 cases of internal fixation failure and no fracture reduction loss were found in group A, while 9 cases of internal fixation failure and 1 case of fracture reduction loss in group B. The incidence of complications in group A was 19.2% (5/26), which was significantly lower than that in group B (54.2%, 13/24) ( χ 2=6.611, P=0.010). CONCLUSION: Compared with the traditional Kirschner wire tension band fixation, the improved Kirschner wire tension band fixation in treatment of type C patellar fracture can shorten the operation time, reduce the incidence of complications, and benefit the functional recovery of knee joint.

Treatment of cervical disc herniation through percutaneous minimally invasive techniques.

PURPOSE: The goal of this study is to compare the therapeutic effectiveness of percutaneous cervical discectomy, percutaneous cervical disc nucleoplasty, and a combination of the two for the treatment of cervical disc herniation and the effective stabilization of the cervical vertebral column. METHODS: A retrospective study was performed from February 2003 to April 2011. One hundred and seventy-one cervical disc herniation patients with a mean age of 47.8 years (ranging from 21 to 74 years) participated in the study and were treated with the three types of percutaneous minimally invasive techniques: percutaneous cervical discectomy (PCD, 97 cases), percutaneous cervical disc nucleoplasty (PCN, 50 cases), and a combination of the two (PCDN, 24 cases). After treatment, the postoperative clinical results and the stability of the cervical vertebral columns of these three groups were evaluated and compared. RESULTS: Patients in the PCD group received follow-up care for approximately 4.1 years (ranging from 0.2 to 8.5 years), while those in the PCN group received only an average of 2.6 years (ranging from 0.3 to 7.8 years), and the PCDN group received an average of 3.3 years (ranging from 0.2 to 8 years of follow-up). According to the Japanese Orthopedic Association scoring system, the functional scores (JOA scores) differed significantly between the pre- and postoperative patients within the three groups (PCD t = 21.849, P = <0.05; PCN t = 14.503, P < 0.05; PCDN t = 8.555, P < 0.05). All patients had been successfully operated on by the same spinal surgeon team. According to the Odom criterion, the clinical outcomes were not significantly different for any of the three groups (the recovery rate using the JOA standard evaluation, F = 2.19, P = 0.116, P > 0.05). The percentages of each procedure that received either an excellent or a good rating were PCD at 81.35 %, PCN at 82.44 % and PCDN at 83.19 %. In addition, the clinical success rates among the three were not significantly different (P > 0.05). Notably, there was no postoperative instability of the cervical vertebral column in any of the patients (P > 0.05), and there was no difference in the pre- or postoperative stability of the cervical vertebral columns in each group. CONCLUSIONS: Each group achieved good clinical outcomes with this safe, minimally invasive spinal surgery for the treatment of cervical disc herniation. In addition, no postoperative risk of cervical instability was found.

Digital three-dimensional model of lumbar region 4-5 and its adjacent structures based on a virtual Chinese human.

OBJECTIVE: To study the methods for constructing a digitized three-dimensional (3D) model of a virtual lumbar region and its adjacent structures in order to assist anatomical study and virtual surgery. METHODS: Images of DSCF5375-p1 to DSCF5745-p1 were taken from the database of the digitized Virtual Chinese human of Southern Medical University in Guangzhou. This region encompasses the superior facet joint of L4 to the inferior edge of the intervertebral body of L5. The regions of interest were interactively segmented from the images utilizing Adobe Photoshop software. The images were further processed using format conversion and segmentation. Finally, a 3D model of the L4-5 region and its neighboring structures was reconstructed with the assistance of Mimics 10.01 software. RESULTS: A digitized 3D model of this part of the virtual lumbar spine and its adjacent structures was reconstructed. This model allows all constructed structures to be displayed individually or jointly, moved or rotated arbitrarily, setting of different transparencies and convenient measurement of the diameters and angles of the reconstructed structures. The 3D model precisely displays the anatomical relationships between all structures and provides a reliable 3D model for a spinal endoscopic surgery simulation system. CONCLUSION: Visualization of the digitized 3D reconstruction of the virtual lower lumbar region displays this region and its adjacent structures stereoscopically and in actuality, thus providing morphological data concerning anatomy, image diagnosis and virtual operations in this region.