Nail Placement Research Articles

Finite element analysis of minimally invasive nail placement and traditional nail placement in the treatment of lumbar 1 vertebral compression fracture.

Using the finite element analysis method to help us better understand the biomechanical changes of the spine after surgery and the changes in the stress distribution around the screw implantation area. The finite element model of L1 vertebral compression fracture was constructed by using a large number of finite element programs. On the fracture model, 2 kinds of internal fixation devices are set up, namely: the first type of 4 screws across the injured vertebra through the adjacent upper and lower vertebrae + transverse connector; the second type of 4 screws crosses the injured vertebra through the adjacent upper and lower vertebrae + non-transverse connector. To study the distribution of the maximum displacement and von Mises stress of the intramedullary pedicle screws and rods of the 2 types of internal fixation devices after implantation in the spine under certain loading conditions. In traditional open pedicle screw fixation, the maximum stress in the pedicle screw fixation system in the direction of 3D movement is higher than in percutaneous pedicle screw fixation. There is no significant difference in the Von Mises stress of the pedicle screw between the 2 procedures when the spine performs flexion-extension and lateral flexion activities. When the spine is rotating axially, the Von Mises stress of the pedicle screw in conventional open surgery is significantly less than that of the screw in percutaneous pedicle screw fixation. Traditional open internal fixation produces stress peaks of 891.7 MPa and 886.34 MPa at the transverse joint during axial rotation. Only when the spine is rotating in the axial direction, the maximum displacement of traditional open pedicle screw fixation is smaller than that of percutaneous pedicle screw fixation. There is no significant difference in the maximum displacement between the 2 procedures when the spine is moving in other directions. Traditional open pedicle screw fixation can strengthen the stability of the spine in the direction of axial rotation, and can also be greater to reduce the maximum stress of the pedicle screw axial rotation, so the clinical treatment of unstable fractures of the thoracolumbar spine instability is of great significance.

Ideal entry point and direction of retrograde intramedullary nailing of the tibia

PurposeTo determine the ideal entry point and direction of retrograde intramedullary nailing of the tibia.MethodsThe imaging data of patients with distal tibial fractures from June 2020 to December 2021 in our hospital were collected, and computer-aided design was performed. The relevant data were imported into the software for processing, so as to obtain a distal tibial fracture model and simulate the retrograde intramedullary nail placement in the tibia. The entry points and angles at which the intramedullary nail could be inserted successfully and the fracture could be maintained in good alignment were overlapped and counted to obtain the safe entry range and angle. The center of this safe range is the ideal entry point for retrograde intramedullary nailing of the tibia, and the mean value of the angle is the ideal direction of entry.ResultsThe ideal entry point of the retrograde intramedullary nailing was located at the midpoint of the medial malleolus in the C-arm fluoroscopic anteroposterior (AP) and lateral view. The ideal nail entry direction was located at the anatomic axis of the medial malleolus in the AP position and at the anatomic axis of the distal tibial metaphysis in the lateral position.ConclusionThe ideal point and direction of nail insertion for retrograde tibial intramedullary nailing is a "double midpoint, double axis" approach.

Dynamic effects of eifferent nail placement strategies on LenkeC scoliosis.

Although the internal fixation technique for scoliosis is effective, there is a great risk of nail placement in actual operation. To compare the effects of three different nail placement strategies on LenkeC patients with scoliosis under cyclic loading. Firstly, the finite element model was established by using CT scanning images and X-ray images of patients with LenkeC scoliosis. Secondly, the validity of the model was verified. Finally, the harmonic response analysis and transient dynamic analysis were carried out. The results showed that the maximum amplitude of each vertebral body appeared in the Z direction at the third natural frequency and the amplitudes of each corresponding vertebral body were very close under three kinds of nail placement. Under different nail placement methods, the uneven distribution of nails would make the model produce obvious stress concentration, but the principal stress of vertebral body and nail rod was far lower than its own yield strength. This showed that under the axial cyclic load, the vertebral bodies of scoliosis tended to have larger impact in Z direction. From the point of view of dynamics, it was feasible to reduce a certain number of nails in operation. This paper revealed that it was feasible to reduce a certain number of nails during surgery.

Detection of Common Anatomical Landmarks and Vertical Trajectories for Freehand Pedicle Screw Placement

It is clinically important for pedicle screws to be placed quickly and accurately. Misplacement of pedicle screws results in various complications. However, the incidence of complications varies greatly due to the different professional titles of physicians and surgical experience. Therefore, physicians must minimize pedicle screw dislocation. This study aims to compare the three nail placement methods in this study, and explore which method is the best for determining the anatomical landmarks and vertical trajectories. This study involved 70 patients with moderate idiopathic scoliosis who had undergone deformity correction surgery between 2018 and 2021. Two spine surgeons used three techniques (preoperative computed tomography scan [CTS], visual inspection-X-freehand [XFH], and intraoperative detection [ID] of anatomical landmarks) to locate pedicle screws. The techniques used include visual inspection for 287 screws in 21 patients, preoperative planning for 346 screws in 26 patients, and intraoperative probing for 309 screws in 23 patients. Observers assessed screw conditions based on intraoperative CT scans (Grade A, B, C, D). There were no significant differences between the three groups in terms of age, sex, and degree of deformity. We found that 68.64% of screws in the XFH group, 67.63% in the CTS group, and 77.99% in the ID group were placed within the pedicle margins (grade A). On the other hand, 6.27% of screws in the XFH group, 4.33% in the CTS group, and 6.15% in the ID group were considered misplaced (grades C and D). The results show that the total amount of upper thoracic pedicle screws was fewer, meanwhile their placement accuracy was lower. The three methods used in this study had similar accuracy in intermediate physicians (P > 0.05). Compared with intermediate physicians, the placement accuracy of three techniques in senior physicians was higher. The intraoperative detection group was better than the other two groups in the good rate and accuracy of nail placement (P < 0.05). Intraoperative common anatomical landmarks and vertical trajectories were beneficial to patients with moderate idiopathic scoliosis undergoing surgery. It is an optimal method for clinical application.

In silico biomechanical analysis of poller screw-assisted small-diameter intramedullary nail in the treatment of distal tibial fractures.

Objective: To evaluate the biomechanical effects of Poller screws (PS) combined with small-diameter intramedullary nails in the treatment of distal tibial fractures at different locations and on different planes. Methods: Nine finite element (FE) models were used to simulate the placement of the intramedullary nail (IMN) and the PS for distal tibial fractures. Structural stiffness and interfragmentary motion (IFM) through the fracture were investigated to assess the biomechanical effects of the PS. The allowable stress method was used to evaluate the safety of the construct. Results: With the axial load of 500N, the mean axial stiffness of IMN group was 973.38 ± 95.65N/mm, which was smaller than that at positions A and B of the coronal group and sagittal group (p < 0.05). The shear IFM of the IMN group was 2.10 ± 0.02mm, which were smaller than that at positions A and B of the coronal group and sagittal group (p < 0.05). Under physiological load, the stresses of all internal fixation devices and the nail-bone interface were within a safe range. Conclusion: In the treatment of distal tibial fractures, placing the PS in the proximal fracture block can obtain better biomechanical performance. The IMN fixation system can obtain higher structural stiffness and reduce the IFM of the fracture end by adding PS.

Abstract #1408105: Treatment of Bisphosphonate Associated Atypical Femur Fracture with a Combination of Teriparatide and a Novel Surgical Technique

Atypical femur fractures (AFF) caused by long term Bisphosphonate use are associated with high rates of delayed healing and non-union, posing a significant challenge in the management of these patients. We describe the case of a 64-year-old female with osteopenia on Bisphosphonate therapy for 15 years who sustained a displaced left AFF following a fall from standing height. She reported a 6-month history of antecedent left groin pain. Radiographs of the left femur showed an acute displaced transverse diaphyseal fracture with lateral cortical thickening and beaking. The right femur radiograph showed features of abnormal cortical remodeling with thickened, irregular cortices. DEXA showed T-scores of -2.1 at the left femoral neck, -1.4 at the left total hip, and -1.4 at the lumbar spine. She underwent an open reduction and internal fixation with insertion of a cephalomedullary nail placed in compression mode. A novel technique of intraoperative removal of the endosteal hypertrophied cortical bone at the fracture with a Midas rex cutting burr was used and there was excellent cortical contact after reduction. She had immediate relief of her pain and was permitted to fully weight-bear postoperatively. Her bisphosphonate was stopped immediately and Teriparatide was initiated at 7 weeks post-operatively. Radiographs 8 weeks after initiation of Teriparatide showed evidence of normal fracture union with mature callus formation. AFF caused by prolonged Bisphosphonate use have a high rate of delayed healing and non-union due to abnormal bone remodeling. Use of Teriparatide post-operatively has been shown to reduce healing time in recent small studies in surgically treated patients. Our case demonstrates expedited healing time when Teriparatide was combined with a novel surgical technique involving removal of a portion of the abnormal fracture end and placement of an intramedullary nail in compression mode. Furthermore, the patient had radiographic evidence of cortical thickening on her right femur, increasing her risk for contralateral AFF. Prophylactic surgical stabilization was recommended but the patient has deferred this. She remains fracture-free and pain-free on the right side, suggesting a possible benefit of Teriparatide use in patients at risk for impending AFF. Our case demonstrates an expedited healing time (3.5 months) relative to previously reported average healing times for AFF (10.7 months), supporting the use of the combination of Teriparatide and a novel surgical technique.

Does the distal nail position impact the rates of misalignment and bone union in distal tibial fractures?

This retrospective study aimed to assess the impact of distal nail placement on misalignment and healing rates in distal tibial fractures. We reviewed all patients with distal tibial fracture treated with intramedullary nailing between 2015 and 2021, and a minimum follow-up of 12months. Distal nail positioning was determined according to the Triantafillou zones. We related these positioning zones to misalignments (alignment ≥ 3°) and too bony union disorders (delayed union, non-union). Out of the 62 patients included, 56 (90.3%) show bone union without additional procedure, 3 (4.8%) with dynamization, and 3 (4.8%) showed non-union. Twenty-one (33.8%) presented misalignment, with valgus in the coronal plane being the most frequent (76.19%). In patients with and without misalignment, the most frequent distal nail position was 2-2 in 47.6% and 80.5%, respectively (p = 0.01). In multivariate analysis, distal nail positioning in the 2-2 zone showed a significant protective effect against misalignment (OR 0.18; p = 0.018), while nail positioning in the 3-2 zone generated a significant risk of misalignment (OR 18.55; p = 0.009). In intramedullary nailing of distal tibial fractures, distal positioning of the nail slightly lateral to the center of the talus in the coronal plane and slightly posterior in the sagittal plane (zone 2-2) allows high alignment percentages to be obtained. Positioning medial to this point in the coronal plane (zone 3) is associated with more significant misalignment and should be avoided.

Comparison of treatment of unstable intertrochanteric fractures by intramedullary and extramedullary implants

Background To achieve union and restore the normal biomechanics of the hip region after unstable trochanteric fractures, surgical intervention is necessary. There are two options for internal fixation: extramedullary and intramedullary. Dynamic hip screw (DHS) as extramedullary fixation was and is still widely used to surgically treat intertrochanteric fractures. However, it sometimes fails to give good results. Intramedullary fixation methods include gamma nail placement, which is considered by some surgeons to be a better choice as it can avoid complications occurring with extramedullary fixation. Our study aimed to conclude which is better to be used to manage unstable intertrochanteric fractures by either DHS or gamma nail regarding the operation requirements (hospital stay, need for blood transfusion, wound complications, and soft tissue damage) and later on evaluate which is better regarding the fracture healing radiologically and functionally. Patients and methods This is a retrospective study of 52 patients with recent unstable intertrochanteric fractures between January 2020 and December 2020. A total of 40 patients continued the study till the last follow-up, where 20 of them were fixed by intramedullary gamma nails as a group I and the other 20 patients were fixed by extramedullary DHS as a group II. The mean age for the group I was 50.05 (20–83) years and the mean age for group II was 60.5 (22–91) years. A total of 14 patients from group I were males and 12 from group II were males. All fractures were classified according to Evan’s classification to be unstable (Evan’s types III, IV, and V). Results Overall, 19 (95%) patients of group I achieved full union and one patient had nonunion with nail breakage. No patients in group I had malunion. A total of 17 (85%) patients of group II achieved good union with one patient having nonunion with implant failure. Moreover, two (10%) patients of group II had femoral shaft medialization and varus malunion. Conclusion This study supported the previous series in the literature, which proved that unstable intertrochanteric fractures can be fixed by intramedullary gamma nails or extramedullary DHS but intramedullary fixation gives better results than extramedullary fixation.

Comparison of curative effect between Tianji robot assisted screw placement and traditional cannulated screw internal fixation for femoral neck fracture

To investigate the clinical efficacy and advantages of Tianji orthopedic robot assisted cannulated screw internal fixation for femoral neck fracture. The clinical data of 41 patients with femoral neck fracture who underwent internal fixation with cannulated screws from January 2019 to January 2022 were retrospectively analyzed. According to different surgical methods, they were divided into Tianji robot group and traditional cannulated screw fixation group (traditional operation group). Among them, there were 18 patients in Tianji robot group including 8 males and 10 females with age of (56.00±4.22) years old, Garden typeⅠ (4 cases), type Ⅱ (11 cases), type Ⅲ (2 cases), and type Ⅳ (1 case). There were 23 patients in the traditional operation group, including 10 males and 13 females, aged (54.87±4.81) years old;there were 5 cases of Garden typeⅠ, 14 cases of type Ⅱ, 3 cases of type Ⅲ and 1 case of type Ⅳ. The operation time, intraoperative blood loss, fluoroscopy times, guide needle placement times, operation costs and other indicators were observed and compared between two groups. Harris score was used to evaluate hip joint function 12 months after operation. The wounds of all patients healed in Grade A without complications. There were significant differences between two groups in terms of operation time, times of intraoperative fluoroscopy, times of guide needle placement, amount of intraoperative bleeding, and operation cost (P<0.05). All 41 patients were followed up for at least 12 months. The fractures of both groups were healed. There was no infection, screw loosening, fracture displacement and femoral head necrosis in Tianji robot group during follow-up;Screw loosening occurred in 2 patients in the traditional operation group during follow-up. At 12 months after operation, Harris hip joint function score of Tianji robot group was higher than that of traditional operation group in daily activity, lameness, joint activity score and total score (P<0.05). Tianji robot assisted nail placement is a better method for the treatment of femoral neck fracture, which improves the surgical efficiency, is more accurate, has higher success rate of one-time nail placement, shorter operation time, less radiation, and has better hip joint function recovery after surgery.

Design and Simulation Analysis of Robot-Assisted Plate Internal Fixation Device for Lower Limb Fractures

Abstract: Internal fixation with steel plates is a common method for the therapy of lower limb fractures. Due to the disadvantages of traditional surgical methods such as high trauma and complications, the application of robots for minimally invasive surgery has become a popular research direction. In this article, we have designed and simulated the overall structure of a steel plate internal fixation device used in conjunction with a robotic arm. Firstly, a finite element model of cortical bone drilling was established based on ABAQUS to obtain the torque and axial force when drilling the cortical bone. Then a virtual prototype of the robot-assisted lower limb bone fracture plate internal fixation device was designed, and the outer shell, drilling mechanism, nail placement mechanism, nail supply mechanism, drive mechanism, and guide sleeve were refined based on the overall mechanical structure of the device, so that the device could continuously perform drilling and nail placement. Afterward, the device was simulated based on ADAMS, and the motion curves of each component were obtained to verify the feasibility of the device’s working principle and to validate the performance of the servo. Finally, the modal analysis of the device was carried out with the finite element software ABAQUS, and the modal parameters of the first six orders were obtained, which were compared with the operating frequencies of the motor and the servo to verify that the device is not easy to resonate during normal operation, and the static strength checks of the key components were carried out, and the stress and deformation clouds and upper limits of flexural values of the components were obtained, which proved that the structure has stability.

Retracted: Mathematical Modeling and Nail Placement Accuracy Analysis of NF-1 Neurofibromatosis Scoliosis.

[This retracts the article DOI: 10.1155/2022/4229377.].

Imaging Evaluation of Insertion Point Accuracy in Retrograde Intramedullary Femoral Nailing.

When compared with visual retrograde intramedullary nail placement in the femur, fluoroscopic retrograde intramedullary nail placement in the femur improved the accuracy of insertion. Ninety-six patients treated with retrograde intramedullary nailing of the femur for femoral fracture were included in this retrospective case-control study, including 48 patients treated with nailing under direct vision and 48 patients treated with nailing under fluoroscopy. Influencing factors potentially associated with the deviation of the needle insertion point on the coronal and sagittal planes (including the needle insertion method, use of limited open reduction, side, intramedullary nail diameter, mechanism of injury, and fracture classification) were analyzed univariately; then, the variables with a p value < 0.20 on univariate analysis were included in the linear regression equation to assess the independent factors associated with needle insertion point deviation. On the coronal plane, the insertion point deviation in the visual nail placement group (1.11 ± 4.08 mm) was not significantly different (p = 0.13) from that in the fluoroscopic nail placement group (-0.44 ± 3.48 mm); on the sagittal plane, the insertion point deviation in the visual nail placement group (4.91 ± 4.67 mm) was significantly greater than that in the fluoroscopic nail placement group (2.08 ± 2.97 mm) (p < 0.01). Visual nail placement was a risk factor for insertion point deviation on the sagittal plane compared with fluoroscopic nail placement (β = -0.84, p < 0.01). Compared with visual nail placement, fluoroscopic nail placement improves the accuracy of insertion on the sagittal plane, with no difference between the two methods on the coronal plane. These findings indicate that surgeons should exercise more caution when placing nails under direct vision.

Treatment of avulsion fracture of inferior pole of patella with improved angle of anchor and double pulley technique

To evaluate the angle of modified anchor nail placement and the curative effect of double pulley technology for the treatment of extreme avulsion fracture of lower patella. From December 2015 to December 2018, a total of 22 patients(10 males and 12 females) with avulsion fracture of the inferior pole of patella were retrospectively analyzed. The average age was (44.00±15.24) years old(range, 19 to 70 years). All patients were treated with modified anchor angle and double pulley technique. The range of motion(ROM) and Bostman score system were used to evaluate the functional recovery of knee joint. All 22 cases were followed up with an average of (30.86±8.00) weeks (18 to 46 weeks). At the last follow-up, ROM of the affected knee was (130.82±4.69) °, and the contralateral knee was (133.23 ± 3.15) °, there was no significant difference between two groups (P>0.05). The average Bostman score was (28.45±1.41) scores, 18 cases were excellent results, 4 cases were good. Improved anchor placement angle and double pulley technique for treatment of extreme avulsion fracture of lower patella is easy to operate, with satisfactory curative effect and good recovery of knee joint function.

CT imaging measurement of sacral related anatomical parameters

To investigate the CT measurement of sacral anatomical parameters and understand the safe nail placement channel of DenisⅠ area with a new sacral butterfly plate. The CT data of 101 normal adult sacrum from January 2020 to June 2020 were retrospectively analyzed, including 49 females and 52 males, aged(49.11±15.02) years old. Firstly, the three-dimensional model of sacrum was reconstruct, the three-dimensional model according to the plane was re segment to be measured, and data measurement and statistical analysis were carried out. The vertical distance from the lower edge of superior sacral articular process to the lower edge of S2 posterior sacral foramen was (42.55±4.73) mm;The horizontal distance from the lateral sacral crest of S1, S2 and S3 hole plane to the sacroiliac joint surface was (19.09±3.07) mm, (15.34±2.69) mm and (8.29±2.48) mm respectively;The plane of S1 hole moves forward from the lateral sacral ridge, the inner and outer angles are (7.49±7.49)° and (24.07±4.89)° respectively;The inside and outside angles of S2 hole plane are (-3.10±8.95)° and (24.95±5.74)° respectively. There were significant differences between different genders except S1 horizontal distance and S1 medial angle, and there was no correlation between age and all data. The new sacral butterfly plate has enough safe nail placement range in DenisⅠ area;There are differences in sacral morphology among adults. The differences are mainly related to gender but not age.

Arthroscopic-assisted fracture reduction combined with robot-navigated nail placement to treat talar neck fractures

This study aims to explore the clinical efficacy of arthroscopic-assisted reduction combined with robot-navigated nail placement in the treatment of talar neck fractures. The clinical data of 13 patients with talar neck fracture in Xuzhou Benevolent Hospital from January 2018 to January 2021 were analyzed in the retrospective study. Among them, there were 9 males and 4 females, aged (36±12) years; there were 8 cases suffered on the right and 5 cases on the left. All patients were reset under arthroscopy and cannulated screws were placed in combination with three-dimensional navigation and positioning of orthopedic robot. The wounds and complications were observed in the postoperative follow-up. The activities of bilateral ankle dorsiflexion and plantar flexion were measured in the last follow-up. The visual analogue scale score (VAS) of pain in the affected feet before operation were compared with that at the last follow-up. The ankle and hind foot work energy scale of American Foot and Ankle Association (AOFAS) was used to assess the ankle function. The results showed that the wounds of 13 patients healed in one stage. The operation time was (95±45) min and the blood lose was (45±10) ml. All the patients were followed-up for (15.0±3.5) months. Two cases developed subtalar arthritis without talus necrosis and fracture nonunion. At the last follow-up, there was no significant difference in the dorsal extension and plantar flexion of the ankle between the affected side and the healthy side (25.8°±1.9° vs 26.2°±2.3°, 44.2°±2.7° vs 44.7°±2.8°, both P>0.05). The VAS score of pain in the affected foot at the last follow-up was 0.53±0.18, it was significantly lower than that before operation (0.87±0.29) (P<0.001). The mean AOFAS ankle and hind foot energy scale of the ankle function was 93.5 at the last follow-up. It's showed that treatment of talus neck fracture with arthroscopy assisted and robot guided nail placement is satisfactory and is worthy of clinical promotion.

Effect of computer virtual technique combined with pelvic reduction frame in the treatment of type C pelvic fracture

To investigate the short-term clinical effect of the computer virtual technique combined with pelvic reduction frame in the treatment of complex pelvic fractures. Thirty patients with Tile C pelvic fractures treated by percutaneous minimally invasive pelvic reduction frame from April 2018 to April 2020 were retrospectively analyzed, including 21 males and 9 females, aged from 19 to 57 (39.40±9.85) years old. The patient's pelvic CT DICOM data were imported into Mimics software to reconstruct the virtual fracture model. Virtual reduction and nail placement were carried out on the fracture model, and then simulated fluoroscopy was carried out to record the ideal fluoroscopy orientation and angle to guide the correct fluoroscopy during operation. The operation time, fluoroscopy times and intraoperative blood loss were recorded. The quality of fracture reduction was evaluated by Matta image score standard, and the postoperative function was evaluated by Majeed function score standard. All 30 patients achieved closed reduction and percutaneous screw fixation. According to Matta score, the excellent and good rate of fracture reduction was 93.3%(28/30). A total of 67 channel screws were inserted, and the excellent and good rate was 98.5%(66/67). The operation time was (173.54±79.31) min, fluoroscopy time was (90.81±41.11) times, intraoperative blood loss was (81.21±43.97) ml. All incisions healed at one stage without broken nails or re-displacement of fractures. All patients were followed up for 12 months. At the final follow-up, Majeed function score was 73 to 94(85.66±5.33) scores. Computer virtual technology combined with pelvic reduction frame could rapidly, accurately and safely reduce and fix unstable pelvic fractures. Computer virtualization could help surgeons to recognition and understanding pelvic fractures, pelvic reduction frame could improve the surgeon's ability to manage complex and unstable pelvic injuries.

Intraoperative assisted O-arm navigation imaging for unstable pelvic fractures in INFIX

To investigate the effect of internal external fixator assisted O-arm navigation imaging in the treatment of unstable pelvic fractures. From May 2019 to November 2019, 15 patients with unstable pelvic fractures were treated by intraoperative O-arm navigation imaging using INFIX technology. There were 6 males and 9 females. The age ranged from 24 to 66 years old. The course of disease ranged from 2 to 14 days. According to Tile classification, there were 1 case of B1 type, 8 cases of B2 type, 3 cases of C1 type, and 3 cases of C2 type. According to Young-Burgess classification, there were 8 cases of LC, 1 case of APC, 4 cases of VS, 2 cases of CM. Preoperative routine pelvic anteroposterior film, entrance position, exit position and pelvic CT three-dimensional reconstruction were performed. Intraoperative O-arm navigation system three-dimensional reconstruction and triplane scanning imaging were used to evaluate the effect of intraoperative reduction. The anterior pelvic ring was fixed with internal external fixator, and the posterior ring was fixed with sacroiliac screw, plate screw or lumbar iliac screw. The operation time, intraoperative bleeding and nail placement were observed and recorded. The quality of fracture reduction was evaluated by Matta standard, and the postoperative function was evaluated by Majeed function score. Wound healing was good in all patients without vascular, nerve and local irritation complications. All the 15 patients were followed up for 10 to 16 months. The fracture reduction was evaluated according to the Matta scoring standard, 9 cases were excellent results, 5 cases were good, and 1 case was medium. The Majeed functional score was 0 to 95 points. The built-in external fixator assisted O-arm navigation imaging system in the treatment of unstable pelvic fractures. The reduction effect is evaluated in advance, the operation time is shortened, and the accuracy of internal fixation is improved. The operation is simple, safe and less bleeding. The operation is in line with the principles of minimally invasive medical treatment and precision medical treatment in orthopedics, which is conducive to the recovery of patients' postoperative function and rapid recovery.

A case-control study of minimally invasive transforaminal interbody fusion with the assistance of robot and traditional fluoroscopy in the treatment of single-space lumbar disc herniation

To compare the safety and nail placement accuracy of fluoroscopy-assisted and robot-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-space lumbar disc herniation. The clinical data of 52 patients with single-space lumbar disc herniation treated by MIS-TLIF from March 2019 to February 2020 were retrospectively analyzed. Among them, 24 patients were treated by robot-assisted MIS-TLIF(group A) and 28 patients were treated by fluoroscopy-assisted MIS-TLIF (group B). The intraoperative blood loss, operation time, intraoperative fluoroscopy times, preoperative and postoperative visual analogue scale(VAS), Japanese Orthopaedic Association(JOA) scores and operation-related complications were recorded in two groups. Gertzbein-Robbins grade according to CT scan was used to evaluate the nail placement after operation. Grade A and B were evaluated as satisfactory nail placement, and grade C, D, and E were evaluated as error placement. Babu's method was used to evaluate the screw's invasion to the superior articular process. The operation time, intraoperative blood loss and intraoperative fluoroscopy times in group A were less than those in group B(P<0.05).VAS and JOA scores of all patients at the final follow-up were significantly improved compared with those before operation(P<0.05), but there was no statistically significant difference between the groups(P>0.05). There were 96 and 112 screws in group A and group B, respectively. Three days after operation, according to the Gertzbein-Robbins grade to evaluate the nail placement accuracy, there were 90 screws of grade A, 5 of grade B, 1 of grade C, no grade D and E in group A;there were 84 screws of grade A, 16 of grade B, 8 of grade C, 4 of grade D, no grade E in group B;the difference between two groups was statistically significant(Z=-3.709, P=0.000). The satisfactory rate of screw placement in group A was 98.96% (95/96), and that of group B was 89.29% (100/112), the difference between two groups was statistically significant (χ2=8.254, P=0.004). Three days after operation, the invasion of superior facet joints by pedicle screws was evaluated according to Babu's method, including 90 screws in grade 0, 4 in grade 1, 2 in grade 2, and 0 in grade 3 in group A;86 in grade 0, 12 in grade 1, 10 in grade 2 and 4 in grade 3 in group B, and the difference was statistically significant(Z=-3.433, P=0.001). There were no serious spinal cord, nerve and vascular injuries and other operation-related complications caused by screw implantation failure in both groups. All patients were followed up from 6 to 12(9.06±1.60) months. The neurological symptoms improved well after operation. During the follow-up period, there was no recurrence of symptoms, loosening or breakage of the internal fixation. Compared with the traditional fluoroscopy-assisted MIS-TLIF, the spinal robot-assisted MIS-TLIF not only has more minimally invasive and safer, but also has higher accuracy in nail placement, lower incidence of upper articular process invasion, and more accurate decompression targets, which can be used for minimally invasive treatment of single-space lumbar disc herniation.

Single oblique lumbar interbody fusion with robot-assisted posterior internal fixation for lumbar degenerative diseases

To investigate the efficacy of single oblique lumbar interbody fusion(OLIF) with robot-assisted posterior internal fixation for the treatment of lumbar degenerative diseases. The clinical data of 67 patients with lumbar degenerative diseases treated from September 2019 to December 2020 was retrospectively analyzed. According to different surgical methods, the patients were divided into traditional group and robot group. The traditional group received traditional OLIF with posterior fluoroscopy percutaneous nail fixation, and the robot group received OLIF with robot-assisted posterior internal fixation. There were 33 patients in traditional group, including 13 males and 20 females, aged from 44 to 82 years old with an average of (59.7±9.1) years; and 34 cases in robot group, including 7 males and 27 females, aged from 45 to 81 years old with an average of(61.6±8.8) years. The operation time, fluoroscopy time, intraoperative blood loss, postoperative out of bed time and hospital stay were recorded. The visual analogue scale (VAS) of low back pain and Oswestry Disability Index(ODI) were compared before operation and 3 days, 3 months after operation between two groups. The accuracy of nail placement was evaluated by postoperative CT scan. Both groups of patients successfully completed the operation and were followed up for more than 3 months. The operation time, fluoroscopy time, intraoperative blood loss, postoperative out of bed time and hospital stay in traditional group were(299.85±15.79) min, (62.58±10.83) min, (118.33±10.80) ml, (2.5±0.7) d, (9.67±2.13) d;and robot group was(248.53±14.22) min, (19.47±3.51) min, (115.74±9.86) ml, (2.3±0.6) d, (9.44±1.93) d, respectively. The symptoms of postoperative low back pain, lower limb pain and numbness were significantly improved in all patients. The operation time and fluoroscopy time in robot group were significantly less than those of traditional group. There was no significant difference in intraoperative blood loss, postoperative out of bed time, hospital stay, VAS and ODI before and after operation (P>0.05). The accuracy of nail placement in robot group was 98.8% (2/160), which was higher than 89.9% (16/158) in traditional group. Treatment of lumbar degenerative diseases with single body position OLIF with robot-assisted posterior minimally invasive internal fixation has less operation time and fluoroscopy time, high nail placement accuracy and accurate surgical effect, which is worthy to be popularized in clinic.

Accuracy and safety of robot assisted pedicle screw placement

To investigate the accuracy and safety of pedicle screw placement assisted by orthopedic robot and C-arm fluoroscopy. The clinical data of 36 patients with spinal diseases underwent surgical treatment from January 2019 to August 2020 was retrospectively analyzed. Among them, 18 cases were implanted pedicle screws assisted by orthopaedic robot(observation group), including 12 males and 6 females, aged from 16 to 61 years with an average of (38.44±3.60) years;there were 1 case of adolescent scoliosis, 1 case of spinal tuberculosis, 7 cases of lumbar spondylolisthesis, 4 cases of thoracic fracture and 5 cases of lumbar fracture. Another 18 cases were implanted pedicle screws assisted by C-arm fluoroscopy(control group), including 10 males and 8 females, aged from 18 to 58 years with an average of (43.22±2.53) years;there were 1 case of adolescent scoliosis, 6 cases of lumbar spondylolisthesis, 6 cases of thoracic fracture and 5 cases of lumbar fracture. The intraoperative fluoroscopy times, nail placement time and postoperative complications were recorded in two groups. CT scan was performed after operation. The Gertzbein-Robbins standard was used to evaluate the accuracy of pedicle screw placement which was calculated. The number of intraoperative fluoroscopy in observation group was(6.89±0.20) times, which was significantly higher than that in control group(14.00±0.18)times(P<0.05). The placement time of each screw in observation group was(2.56±0.12) min, which was significantly different from that in control group(4.22±0.17) min (P<0.05). One case of incision infection occurred in control group after operation, and recovered after active dressing change. During the follow-up period, no serious complications such as screw loosening and fracture occurred in two groups, and there was no significant difference in complications between two groups(P>0.05). A total of 107 screws were placed in observation group, including 101 screws in class A, 4 in class B, 2 in class C, 0 in class D and 0 in class E, the accuracy rate of pedicle screw placement=[(number of screws in class A+B) / the number of all screws placed in the group] ×100%=98.1%(105/107); and a total of 104 screws were placed in control group, including 90 screws in class A, 4 in class B, 5 in class C, 5 in class D and 0 in class E, the accuracy rate of pedicle screw implantation=[(number of screws in class A+B/the number of all screws placed in the group]×100%=90.3% (94/104); there was significant difference between two groups (P<0.05). Orthopaedic robot assisted pedicle screw placement has the advantages of less fluoroscopy times, shorter screw placement time and higher accuracy, which can further improve the surgical safety and has a broad application prospect in the orthopaedic.