Objective To investigating the safety and accuracy of artificial intelligence (AI) assisted automatic planning of pedicle screws parallel to sagittal plane for C1. Methods The subjects who completed cervical CT scan in Zigong Fourth People’s Hospital btween January 2020 and December 2023 were selected. The subjects who completed cervical CT scan were randomly divided into two groups using a random number table method. Among them, 80% were used as the training model (training group), and 20% were used as the validation model (validation group). The original cervical CT data of the training group were imported into ITK-SNAP software to mark the feature points. Four feature points were selected. In order to obtain the weighted function model of the four feature points, training group were trained with the spatial key point location algorithm. pedicle trajectory based on the four key points obtained. Finally, the algorithm was compiled to form a visual interface, and imported into the verification group of annular vertebral CT data to calculate the pedicle screw trajectory. Results A total of 500 patients were included. Among them, there were 400 cases in the training group and 100 cases in the validation group. The average positioning error of spatial key points is (0.47±0.16) mm. The average distance between the planned pedicle screw center line and the internal edge of the pedicle was (2.86±0.12) mm. Pedicle screw placement parallel to the sagittal plane and 3D display can be safely performed for the C1 pedicle that is large enough to accommodate a 3.5 mm diameter screw without cortical breakthrough. Conclusions For pedicle screw planning parallel to the sagittal plane in C1, training based on the spatial positioning algorithm of anterior and posterior tubercles and bilateral tangential points can obtain a safe and accurate pedicle screw trajectory. It provides theoretical basis for orthopedic robot automatic screw placement. For vertebral bodies with narrow or deformed pedicles, further expansion of the training data is needed to expand the adaptive range and improve the accuracy of the algorithm.
Objective To explore the surgical feasibil ity and cl inical outcome of transpedicle screw fixation in treatment of atlantoaxial instabil ity and dislocation. Methods From January 2007 to June 2009, 16 patients with atlantoaxial instabil ity and dislocation were treated with transpedicle screw fixation. There were 13 males and 3 females, with a mean age of 42 years (range, 24-61 years). The transpedicle screw fixation was employed in 5 patients with old odontoid fracture (4 of Anderson type II and 1 of type III), in 4 patients with fresh odontoid fracture, in 4 patients with traumatic disruption of transverse atlantal l igament, and in 3 patients with congenital odontoid disconnection for atlantoaxial instabil ity. All patients had symptoms of cervical pain and l imition of cervical motion, 10 patients compl icated by dyscinesia and hypoesthesia of extremities. The Japanese Orthopaedic Association (JOA) score before operation was from 5 to 13, with an average of 8.5. The image examination showed atlantoaxial instabil ity or dislocation in all patients. Granulated autogenous il ium (20-30 g) was placed onto the surface of the posterior arches of both atlas and axis in some patients with old fracture of odontoid process or disruption of transverse atlantal l igament. Results The mean operative time and bleeding amount were 1.6 hours (1.2-2.5 hours) and 100 mL (50-200 mL), respectively. All the incision healed by first intension. All patients were followed up for 3-18 months, with an average of 11.5 months. The JOA score 3 months after operation was from 12 to 17, with an average of 14.2. All screws were successfully placed in atlas and axis. No postoperative compl ications such as vertebral artery injury, dural rupture, exacerbation of neurological symptoms, wound infection, and broken srews were observed in 16 cases. Postoperative radiograph and CT showed that only one screw penetrated into vertebral canal, but there was no neurological symptoms. Bony fusion was observed after 6 to 18 months of operation, and atlantoaxial rotational function in all patients restored satisfactorily, but axial rotation was partially lost. Conclusion Transpedicle screw fixation in upper cervical spine for treatment of atlantoaxial instabil ity and dislocation is safe and rel iable
ObjectiveTo investigate the effectiveness of cervical pedicle screw implantation technique under regional method.MethodsThe clinical data of 85 patients who met the selection criteria between April 2010 and May 2018 were retrospectively analyzed. There were 57 males and 28 females, aged 35-68 years, with an average of 57.6 years. Among them, there were 10 cases of ossification of posterior longitudinal ligament, 68 cases of cervical spondylosis with multilevel stenosis, 3 cases of cervical tumor, 1 case of congenital malformation, and 3 cases of cervical trauma; the lower cervical spine lesions involved C3-C7. Preoperative Frankel spinal cord injury grading: 2 cases of grade C, 51 cases of grade D, and 32 cases of grade E. Cervical pedicle screw implantation technique under regional method was performed with a total of 618 pedicle screws. Postoperative changes in neurological symptoms were observed; cervical mouth opening anteroposterior and lateral X-ray films and cervical CT examinations were performed to evaluate the pedicle screws position.ResultsThe operation time was 2.5-4.0 hours, with an average of 3.0 hours. The intraoperative blood loss was 180-550 mL, with an average of 345 mL. No intraoperative vascular or nerve injury occurred. The patients with neurological symptoms were relieved to varying degrees. There were 2 cases of superficial incision infection after operation, the wound healed after enhanced dressing change. The postoperative hospital stay was 5-14 days, with an average of 8.4 days. At discharge, Frankel neurological grading was grade D in 26 patients and grade E in 59 patients. All the patients were followed up 6-24 months, with an average of 13 months. At last follow-up, cervical X-ray films showed the good pedicle screw fixation without loosening. Cervical CT evaluated the position of pedicle screws: 523 pedicle screws (84.7%) in grade Ⅰ, 80 (12.9%) in grade Ⅱ, and 15 (2.4%) in grade Ⅲ; the accuracy rate of the screw position was 97.6%.ConclusionCervical pedicle screw implantation technique under regional method can significantly improve the success rate of screw implantation. It is easy to operate, does not destroy the bone cortex, and has stable fixation.
Objective To evaluate the fixation strength of expansive pedicle screw (EPS) at different bone mineral density (BMD) levels, further to provide theoretical evidence for the clinical application of the EPS in patients with osteoporosis. Methods Fresh human cadaver spines (T12-L5 spines) were divided into 4 levels: normal BMD, osteopenia, osteoporosis, and severe osteoporosis according to the value of BMD, 12 vertebra in each level. Conventional pedicle screw (CPS) or EPS was implanted into the bilateral vertebra in CPS group and EPS group, respectively, 12 screws in each group per BMD level. Screw pullout tests were conducted. The maximum pullout strength, stiffness, and energy absorption were determined by an AG-IS material testing machine with constant rate of loading in a speed of 5 mm/ min. Results With the decline of BMD from normal to severe osteoporosis level, the maximum pullout strength and the stiffness correspondingly declined (P lt; 0.05). In CPS group, the energy absorption gradually decreased (P lt; 0.05); in EPS group, significant difference was found between other different BMD levels (P lt; 0.05) except between normal BMD and osteopenia and between osteoporosis and severe osteoporosis (P gt; 0.05). At the same BMD level, the maximum pullout strength of EPS group was significantly larger than that of CPS group (P lt; 0.05); the stiffness of EPS group was significantly higher than that of CPS group (P lt; 0.05) except one at normal BMD level; and no significant difference was found in the energy absorption between 2 groups (P gt; 0.05) except one at osteopenia level. No significant difference was found in maximum pullout strength, stiffness, and energy absorption between EPS group at osteoporosis level and CPS group at osteopenia level (P gt; 0.05); however, the maximum pullout strength, stiffness, and energy absorption of EPS group at severe osteoporosis level were significantly lower than those of CPS group at osteopenia level (P lt; 0.05). Conclusion Compared with CPS, the EPS can significantly improve the fixation strength, especially in patients with osteopenia or osteoporosis.
ObjectiveTo investigate reliability and short-term effectiveness of axis laminar screws for reducible atlantoaxial dislocation (RAAD).MethodsA clinical data of 41 patients with RAAD who were admitted between February 2013 and February 2018 and met the inclusion criteria was retrospectively analyzed. The atlases in all patients were fixated by lateral mass screws, and the axes were fixed by laminar screws in 13 cases (LS group) and by pedicle screws in 28 cases (PS group). There was no significant difference in gender, age, and preoperative Japanese Orthopedic Association (JOA) score between the two groups (P>0.05). The effectiveness was estimated by post-operative JOA score; and the accuracy of the axis screw, atlantoaxial bone graft fusion, and the fixation stability were examined by X-ray film and CT.ResultsAll incisions healed by first intention. All patients were followed up 12-17 months (mean, 13.8 months) in LS group and 12-20 months (mean 14.1 months) in PS group, and the difference in follow-up time was not significant (Z=−0.704, P=0.482). At last follow-up, JOA scores were 13.9±1.6 in LS group and 14.3±1.8 in PS group, which significantly improved when compared with the pre-operative scores in the two groups (t=−9.033, P=0.000; t=−15.835, P=0.000); while no significant difference was found between the two groups (t=−0.630, P=0.532). Twenty-five screws of 26 screws in LS group and 54 screws of 56 screws in PS group were implanted accurately, with no significant difference in the accuracy of the axis screw between the two groups (Z=−0.061, P=0.951). All patients obtained atlantoaxial bone graft fusion, except 1 case in PS group. There was no significant difference in the atlantoaxial bone graft fusion between the two groups (Z=−0.681, P=0.496).ConclusionFor RAAD, Axis laminar screws can maintain the atlantoaxial primary stability and had a good short-term effectiveness. So, it could be an alternative and reliable technique for axis screw.
To analyze the effectiveness of posterior pedicle screw system combined with interbodyfusion in treating lumbar spondylol isthesis. Methods Between January 2005 and January 2009, 26 patients with lumbar spondylol isthesis underwent posterior pedicle screw system combined with interbody fusion, including 11 males and 15 females with an average age of 56.8 years (range, 36-73 years). The disease duration was 7 months to 11 years. The affected lumbars were L3 in 3 cases, L4 in 12 cases, and L5 in 11 cases. According to the Meyerding evaluating system, 21 cases were classified as degree III, 5 cases as degree III-IV, and 1 case as degree IV. The cl inical results were investigated by measuring radiographic measurements, including Taillard index, Boxall index, sl i pping angle, lumbar lordosis angle,and intervertebral height index preoperatively, immediately, 2 weeks and 3 months postoperatively, respectively. SUK’s criteria was used to judge bone graft fusion. Results Primary heal ing of the incisions was achieved in all cases. Allpatients were followed up 25.8 months on average (range, 10-51 months). There were significant differences in Taillardindex, Boxall index, sl i pping angle, lumbar lordosis angle, and intervertebral height index between preoperatively andimmediately, 2 weeks, 3 months after operation (P lt; 0.05). Bone graft fusion was achieved at 3-8 months after operation(mean, 3.5 months); and the fusion rate was 100%. According to Japanese Orthopedic Association (JOA) scoring, theresults were excellent in 17 cases, good in 7 cases, fair in 1 case, and poor in 1 case; and the excellent and good rate was 92.3%. Compl ications occurred in 2 cases, including nail or rod breakage and nerve injury, and they were cured aftertreatment. Conclusion Posterior pedicle screw system combined with interbody fusion treating lumbar vertebralspondylol isthesis can afford sol id internal fixation and achieve a satisfactory reduction, so it maybe an ideal procedure and a worthy recommended method for treating lumbar spondylol isthesis.
Accurate placement of pedicle screws is a key factor of spinal surgery. Investigation of a new real-time intra-operative monitoring method is an important area of clinical application research which makes a contribution to planting pedicle screw accurately. Porcine spines were chosen as experimental objects.The changes of reduced scattering coefficient (μ's) along normal puncture path, medial perforation path and lateral perforation path were measured and studied. A conclusion is drawn that there are two distinct peaks throughout the puncture process, appearing at the junction of cancellous bone and cortical bone, at the beginning and at the end, respectively. The reduced scattering coefficient is proved to be a good monitoring factor which can identify whether the screw is about to reach the critical position of the spine puncture. Moreover, the variation provides an important reference for spinal surgical navigation process.
Objective To investigate the safety and accuracy of robot-assisted pedicle screw implantation in the adolescent idiopathic scoliosis (AIS) surgery. Methods The clinical data of 46 patients with AIS who were treated with orthopedics, bone graft fusion, and internal fixation via posterior approach between June 2018 and December 2019 were analyzed retrospectively. Among them, 22 cases were treated with robot-assisted pedicle screw implantation (robot group) and 24 cases with manual pedicle screw implantation without robot assistance (control group). There was no significant difference in gender, age, body mass index, Lenke classification, and preoperative Cobb angle of the main curve, pain visual analogue scale (VAS) score, Japanese Orthopaedic Association (JOA) score between the two groups (P>0.05). The intraoperative blood loss, pedicle screw implantation time, intraoperative pedicle screw adjustment times, and VAS and JOA scores after operation were recorded. The Cobb angle of the main curve was measured on X-ray film and the spinal correction rate was calculated. The screw position and the accuracy of screw implantation were evaluated on CT images. Results The operation completed successfully in the two groups. The intraoperative blood loss, pedicle screw implantation time, and pedicle screw adjustment times in the robot group were significantly less than those in the control group (P<0.05). There was 1 case of poor wound healing in the robot group and 2 cases of mild nerve root injury and 2 cases of poor incision healing in the control group, and there was no significant difference in the incidence of complications between the two groups (P=0.667). All patients in the two groups were followed up 3-9 months (mean, 6.4 months). The VAS and JOA scores at last follow-up in the two groups were superior to those before operation (P<0.05), but there was no significant difference in the difference of pre- and post-operative scores between the two groups (P>0.05). The imaging review showed that 343 screws were implanted in the robot group and 374 screws in the control group. There were significant differences in pedicle screw implantation classification and accuracy between the two groups (89.5% vs 79.1%)(Z=−3.964, P=0.000; χ2=14.361, P=0.000). At last follow-up, the Cobb angles of the main curve in the two groups were significantly lower than those before operation (P<0.05), and there was significant difference in the difference of pre- and post-operative Cobb angles between the two groups (t=0.999, P=0.323). The spinal correction rateswere 79.82%±5.33% in the robot group and 79.62%±5.58% in the control group, showing no significant difference (t=0.120, P=0.905). Conclusion Compared with manual pedicle screw implantation, robot-assisted pedicle screw implantation in AIS surgery is safer, less invasive, and more accurate.
Objective To explore some operative problems of correcting paralytic scoliosis(PS) by using vertebral pedicle screwsrods system. Methods From May 2000 to May 2005, 18 patients with PS were corrected by screwsrods system which were made of titanium alloy.There were 10 males and 8 females, aging from 11 to 26 years. The primary disease included poliomyelitis in 13 patients and myelodysplasia (MS) in 5 patients (2 cases for second correction) with scoliosis of an average 85° Cobb angle (55-125°). The pelvic obliquity was found in all patients with an average 24° angle (355°).Of the 18 patients,3 cases were given perioperative halo-pelvic traction, 2 cases were given vertebral wedge osteotomy and correction and fixation, the other patients were purely underwent the treatment of pedicle screwrods system implants. Fusion segment at operation ranged from 6 to 15 sections, applied screws the most was 16,the fewest was 6. Results There were no wound infections and neurologic complications, all wounds healed by the first intention. Allscoliosis obtained obvious correction (P＜0.001), the correction rate averaged 52.95% (44%-81%); the majority of lumbar kyphosis and pelvic obliquity were apparently corrected. The average clinical follow-up (16 cases) was 21 months(6-36 months),there was no implants failure. One patient with MS had a worse Cobb magnitude, the other patients had no curve progression (P＞0.05). Conclusion The use of vertebral pedicle screwsrods fixation to multiple vertebral bodys and short segment fusion for PS, the treatment method is reliable and the outcome is satisfactory. While performing the correcting operative procedures, the spinal, pelvic and lower extremity deformities and functions should be all considered as a whole.
Objective To investigate the influence of axis pedicle and intra-axial vertebral artery (IAVA) alignment on C2 pedicle screw placement by measuring the data of head and neck CT angiography. MethodsThe 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 C3 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 C2 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 C2 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. ResultsThe rate of C2 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 C2 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. ConclusionVertebral 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.