共查询到20条相似文献,搜索用时 15 毫秒
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Purpose
To review our experience with robotic guided S2-alar iliac (S2AI) screw placement.Methods
We retrospectively reviewed patients who underwent S2AI fixation with robotic guidance. Screw placement and deviation from the preoperative plan were assessed by fusing preoperative CT (with the planned S2AI screws) to postoperative CT. The software’s measurement tool was used to compare the planned vs. actual screw placements in axial and lateral views, at entry point to the S2 pedicle and at a 30 mm depth at the screws’ mid-shaft, in a resolution of 0.1 mm. Medical charts were reviewed for technical issues and intra-operative complications.Results
35 S2AI screws were reviewed in 18 patients. The patients’ mean age was 60 years. No intra-operative complications that related to the placement of S2AI screws were reported and robotic guidance was successful in all 35 screws. Post-operative CT scans showed that all trajectories were accurate. No violations of the iliac cortex or breaches of the anterior sacrum were noted. At the entry point, the screw deviated from the pre-operative plan by 3.0 ± 2.2 mm in the axial plane and 1.8 ± 1.6 mm in the lateral plane. At 30 mm depth, the screw deviated from the pre-operative plan by 2.1 ± 1.3 mm in the axial plane and 1.2 ± 1.1 mm in the lateral plane.Conclusions
Robotic guided S2AI screw placement is feasible and accurate. No screw malpositions or complications that related to the placement of S2AI screws occurred in this series. Larger studies are needed to assess the long-term clinical outcomes of robotic guided sacral-pelvic fixation.3.
Janhua Wang Hong Xia Qingshui Ying Yang Lu Zenghui Wu Fzhi Ai Xiangyang Ma 《European spine journal》2013,22(7):1547-1552
Study design
Retrospective case series.Objectives
To identify the variation of C2 vertebral artery groove (VAG) based on the thin-slice computed tomography (CT) scan and choose an individual screw placement method to decrease risk of malposition.Background
C2 pedicle screws can be successful anchors for a variety of cervical disorders. However, variations of VAG may cause malposition and breach when C2 transpedicle screw was inserted. Recognizing the variations of vertebrae artery groove (VAG) in C2 and choosing an individual screw placement method (transpedicle or translaminar) may be helpful for avoiding violation and decreasing the operation risk in upper cervical surgery.Methods
From January 2009 to December 2010, a total 45 patients with upper cervical disorders underwent 1–mm-thin-slice CT scans along the C2 pedicle direction to obtain the consecutive spectrum of C2 VAG were included in this study. The C2 VAG (types I, II, III, and IV) was subgrouped based on parameter e (the vertical distance from the apex of VAG to the upper facet joint surface) and parameter a (horizontal distance from the entrance of VAG to the vertebrae canal). Subsequently, individual strategy was used to avoid the VAG violation.Results
The variations of C2 VAG in these 45 patients include the following: type I 53 (58.9 %), type II 16 (17.8 %) type III 13 (14.4 %), and type IV 8 (8.9 %). Transpedicle screws of C2 were used in types I, III, and IV VAGs (n = 74); translaminar screws were inserted in type II subgroup (n = 16). Postoperative CT scans showed that there were two pedicle screws violated into the artery groove, and no translaminar screw breached into the vertebrae canal. All the other screws were in right position. None of the 45 patients had severe complications such as spinal cord injury, dura tear, and infection.Conclusion
Thin-slice CT scan along the C2 pedicle direction to analysis the variations of C2 VAG can help choose an individual screw placement method (transpedicle or translaminar) with minimal complication for C2 screw fixation. 相似文献4.
Liujun Zhao Jinjiong Hong Meghan E. Wandtke Rongming Xu Weihu Ma Weiyu Jiang Yongjie Gu Jianqing Chen Liran Wang Jiayong Liu Nabil A. Ebraheim 《European spine journal》2016,25(6):1716-1723
Study design
We evaluated the trajectory and the entry points of anterior transpedicular screws (ATPS) in the cervicothoracic junction (CTJ).Objective
This study aimed at investigating the feasibility of ATPS fixation in the CTJ.Summary of background data
Application of an ATPS in the lower cervical spine has been reported; however, there were no reports exploring the feasibility of anterior transpedicular screw fixation in the CTJ.Methods
CT scans were performed in 50 cases and multiplanar reformation was used to measure the related parameters on pedicle axis view at C6–T2. Transverse pedicle angle, outer pedicle width, pedicle axis length, distance transverse intersection point (DtIP), sagittal pedicle angle, anterior vertebral body height, outer pedicle height, and distance sagittal intersection point (DsIP) were measured. The prozone of CTJ was divided into three different regions, which were named as the “manubrium region”, the region “above” and “below” the manubrium. The distribution of the trajectory of sagittal pedicle axes was recorded in the three regions and the related data were statistically analyzed.Results
There was no statistical difference in gender (P > 0.05). The transverse pedicle angle decreased from C6 (46.77° ± 2.72°) to T2 (20.62° ± 5.04°). DtIP increased from C6 to T2. DsIP was an average of 7.17 mm. The sagittal pedicle axis lines of the C6 and C7 were located in the region above the manubrium. T1 was mainly in the manubrium region followed by the region above the manubrium. T2 was mainly located in the manubrium region followed by the region below the manubrium.Conclusion
Implantation of ATPS at C6, C7, and some T1 is feasible through the low anterior cervical approach, while it is almost impossible to approach T2 that way.5.
Mazda Farshad Nadja A. Farshad-Amacker Elias Bachmann Jess G. Snedeker Samuel L. Schmid 《Acta neurochirurgica》2014,156(11):2147-2151
Background
While convergent placement of pedicle screws in the axial plane is known to be more advantageous biomechanically, surgeons intuitively aim toward a parallel placement of screws in the sagittal plane. It is however not clear whether parallel placement of screws in the sagittal plane is biomechanically superior to a non-parallel construct. The hypothesis of this study is that sagittal non-parallel pedicle screws do not have an inferior initial pull-out strength compared to parallel placed screws.Methods
The established lumbar calf spine model was used for determination of pull-out strength in parallel and non-parallel intersegmental pedicle screw constructs. Each of six lumbar calf spines (L1-L6) was divided into three levels: L1/L2, L3/L4 and L5/L6. Each segment was randomly instrumented with pedicle screws (6/45 mm) with either the standard technique of sagittal parallel or non-parallel screw placement, respectively, under fluoroscopic control. CT was used to verify the intrapedicular positioning of all screws. The maximum pull-out forces and type of failure were registered and compared between the groups.Results
The pull-out forces were 5,394 N (range 4,221 N to 8,342 N) for the sagittal non-parallel screws and 5,263 N (range 3,589 N to 7,554 N) for the sagittal-parallel screws (p?=?0.838). Interlevel comparisons also showed no statistically significant differences between the groups with no relevant difference in failure mode.Conclusion
Non-parallel pedicle screws in the sagittal plane have at least equal initial fixation strength compared to parallel pedicle screws in the setting of the here performed cadaveric calf spine experiments. 相似文献6.
Purpose
To assess the pedicle morphology in the lower thoracic and lumbar spine in an Indian population and to determine the causes of pedicle wall violation by pedicle screws.Methods
Computerised tomographic scans of 135 consecutive patients with thoracolumbar and lumbar spine fractures were prospectively analysed to determine the pedicle morphology. The transverse pedicle angle, pedicle diameter and screw path length at 527 uninjured levels were measured. Post-operative CT scans of 117 patients were analysed to determine the accuracy of 468 pedicle screws at 234 vertebrae.Results
The lowest (mean ± SD) transverse pedicle width in the lower thoracic spine was 5.4 ± 0.70 mm, whereas in the lumbar spine it was 7.2 ± 0.87 mm. The shortest (mean ± SD) screw path length in lower thoracic pedicles was 35.8 ± 2.10 and 41.9 ± 2.18 mm in the lumbar spine. The mean transverse pedicle angle in the lower thoracic spine was consistently less than 5°, whereas it gradually increased from L1 through L5 from 8.5° to 30°. Forty-one screws violated the pedicle wall, due to erroneous angle of screw insertion.Conclusions
In the current study, pedicle dimensions were smaller compared to the Western population. In Indian patients, pedicle screws of 5 mm diameter and 30 mm length, and 6 mm diameter and 35 mm length can safely be used in the lower thoracic and lumbar spine, respectively. However, it is important to assess the pedicle morphology on imaging prior to pedicle fixation.7.
Masashi Uehara Jun Takahashi Shota Ikegami Keijiro Mukaiyama Shugo Kuraishi Masayuki Shimizu Toshimasa Futatsugi Nobuhide Ogihara Hiroyuki Hashidate Hiroki Hirabayashi Hiroyuki Kato 《European spine journal》2014,23(10):2189-2195
Study design
A cross-sectional study of the data retrospectively collected by chart review.Objectives
This study aimed to clarify screw perforation features in 129 consecutive patients treated with computer-assisted cervical pedicle screw (CPS) insertion and to determine important considerations for computer-assisted CPS insertion.Summary of background data
CPS fixation has been criticized for the potential risk of serious injury to neurovascular structures. To avoid such serious risks, computed tomography (CT)-based navigation has been used during CPS insertion, but screw perforation can occur even with the use of a navigation system.Methods
The records of 129 consecutive patients who underwent cervical (C2–C7) pedicle screw insertion using a CT-based navigation system from September 1997 to August 2013 were reviewed. Postoperative CT images were used to evaluate the accuracy of screw placement. The screw insertion status was classified as grade 1 (no perforation), indicating that the screw was accurately inserted in pedicle; grade 2 (minor perforation), indicating perforation of less than 50 % of the screw diameter; and grade 3 (major perforation), indicating perforation of 50 % or more of the screw diameter. We analyzed the direction and rate of screw perforation according to the vertebral level.Results
The rate of grade 3 pedicle screw perforations was 6.7 % (39/579), whereas the combined rate of grades 2 and 3 perforations was 20.0 % (116/579). No clinically significant complications, such as vertebral artery injury, spinal cord injury, or nerve root injury, were caused by the screw perforations. Of the screws showing grade 3 perforation, 30.8 % screws were medially perforated and 69.2 % screws were laterally perforated. Of the screws showing grades 2 and 3 perforation, 21.6 % screws were medially perforated and 78.4 % screws were laterally perforated. Furthermore, we evaluated screw perforation rates according to the vertebral level. Grade 3 pedicle screw perforation occurred in 6.1 % of C2 screws; 7.5 % of C3 screws; 13.0 % of C4 screws; 6.5 % of C5 screws; 3.2 % of C6 screws; and 4.0 % of C7 screws. Grades 2 and 3 pedicle screw perforations occurred in 12.1 % of C2 screws, 22.6 % of C3 screws, 31.5 % of C4 screws, 22.2 % of C5 screws, 14.4 % of C6 screws, and 12.1 % of C7 screws. C3–5 screw perforation rate was significantly higher than C6–7 (p = 0.0024).Conclusions
Careful insertion of pedicle screws is necessary, especially at C3 to C5, even when using a CT-based navigation system. Pedicle screws tend to be laterally perforated. 相似文献8.
Florian Fensky Rebecca A. Kueny Kay Sellenschloh Klaus Püschel Michael M. Morlock Johannes M. Rueger Wolfgang Lehmann Gerd Huber Nils Hansen-Algenstaedt 《European spine journal》2014,23(4):724-731
Purpose
The established technique for posterior C1 screw placement is via the lateral mass. Use of C1 monocortical pedicle screws is an emerging technique which utilizes the bone of the posterior arch while avoiding the paravertebral venous plexus and the C2 nerve root. This study compared the relative biomechanical fixation strengths of C1 pedicle screws with C1 lateral mass screws.Methods
Nine human C1 vertebrae were instrumented with one lateral mass screw and one pedicle screw. The specimens were subjected to sinusoidal, cyclic (0.5 Hz) fatigue loading. Peak compressive and tensile forces started from ±25 N and constantly increased by 0.05 N every cycle. Testing was stopped at 5 mm displacement. Cycles to failure, displacement, and initial and end stiffness were measured. Finally, CT scans were taken and the removal torque measured.Results
The pedicle screw technique consistently and significantly outperformed the lateral mass technique in cycles to failure (1,083 ± 166 vs. 689 ± 240 cycles), initial stiffness (24.6 ± 3.9 vs. 19.9 ± 3.2 N/mm), end stiffness (16.6 ± 2.7 vs. 11.6 ± 3.6 N/mm) and removal torque (0.70 ± 0.78 vs. 0.13 ± 0.09 N m). Only 33 % of pedicle screws were loose after testing compared to 100 % of lateral mass screws.Conclusions
C1 pedicle screws were able to withstand higher toggle forces than lateral mass screws while maintaining a higher stiffness throughout and after testing. From a biomechanical point of view, the clinical use of pedicle screws in C1 is a promising alternative to lateral mass screws. 相似文献9.
Gerit Kulik Etienne Pralong John McManus Damien Debatisse Constantin Schizas 《European spine journal》2013,22(9):2062-2068
Purpose
Neurophysiological monitoring aims to improve the safety of pedicle screw placement, but few quantitative studies assess specificity and sensitivity. In this study, screw placement within the pedicle is measured (post-op CT scan, horizontal and vertical distance from the screw edge to the surface of the pedicle) and correlated with intraoperative neurophysiological stimulation thresholds.Methods
A single surgeon placed 68 thoracic and 136 lumbar screws in 30 consecutive patients during instrumented fusion under EMG control. The female to male ratio was 1.6 and the average age was 61.3 years (SD 17.7). Radiological measurements, blinded to stimulation threshold, were done on reformatted CT reconstructions using OsiriX software. A standard deviation of the screw position of 2.8 mm was determined from pilot measurements, and a 1 mm of screw—pedicle edge distance was considered as a difference of interest (standardised difference of 0.35) leading to a power of the study of 75 % (significance level 0.05).Results
Correct placement and stimulation thresholds above 10 mA were found in 71 % of screws. Twenty-two percent of screws caused cortical breach, 80 % of these had stimulation thresholds above 10 mA (sensitivity 20 %, specificity 90 %). True prediction of correct position of the screw was more frequent for lumbar than for thoracic screws.Conclusion
A screw stimulation threshold of >10 mA does not indicate correct pedicle screw placement. A hypothesised gradual decrease of screw stimulation thresholds was not observed as screw placement approaches the nerve root. Aside from a robust threshold of 2 mA indicating direct contact with nervous tissue, a secondary threshold appears to depend on patients’ pathology and surgical conditions. 相似文献10.
Purpose
To evaluate difference in accuracy of pedicle screw insertion in thoracic and lumbosacral spine using a straight pedicle probe vis-à-vis a curved one.Methods
Prospective, comparative, non-randomized, single-blind study. Straight and curved pedicle probes used on opposite sides of same vertebra in patients undergoing thoracolumbar pedicle screw fixation for various indications. Postoperative blinded evaluation for pedicle breaches done with a CT scan. Pedicle breaches graded as grade 0: no breach, grade 1: <2 mm, grade 2: 2–4 mm and grade 3: >4 mm breach.Results
After appropriate statistical power analysis, 300 screws inserted in 59 patients from T4–L5 levels. No significant differences noted between the two probes in terms of screw length [two-tailed p = 0.16]; grade 0 screws [two-tailed p = 0.49] or screws with grade 2/3 breaches [two-tailed p = 0.68]. With the right-hand-dominant operating-surgeon standing to left of patient during surgery, no difference noted between the two probes for either the right or left-side pedicle screw insertion [two-tailed p = 1]. Repeating these tests in the subset of thoracic pedicle screws too, revealed no significant difference.Conclusions
No significant difference in outcome of pedicle screw insertion with either a straight or a curved pedicle probe. 相似文献11.
Is the 4 mm height of the vertebral artery groove really a limitation of C1 pedicle screw insertion?
Da-Geng Huang Si-Min He Jun-Wei Pan Hua Hui Hui-Min Hu Bao-Rong He Hui Li Xue-Fang Zhang Ding-Jun Hao 《European spine journal》2014,23(5):1109-1114
Purpose
To explore the feasibility and effectiveness of C1 pedicle screw fixation in patients whose atlas vertebral artery groove (defined as the C1 pedicle) height is less than 4 mm, but with a medullary canal.Methods
From January 2010 to January 2013, 7 patients (6 males, 1 female) with atlantoaxial instability whose C1 pedicle height was less than 4.0 mm on one or both sides were treated by C1 pedicle screw fixation at our institution. Thirteen of the 14 C1 pedicles were less than 4.0 mm in height, but all had a medullary canal. Patients were followed up at regular intervals. Postoperative computed tomography (CT) scans were performed to assess if C1 pedicle screw placement was successful. Clinical outcomes were evaluated according to postoperative complications, the American Spinal Injury Association grading system, and bone graft status.Results
Thirteen C1 pedicles with a height less than 4.0 mm were inserted by 13 3.5- or 4.0-mm-diameter pedicle screws, and one C1 pedicle whose height was 4.1 mm was inserted by a 4.0-mm-diameter pedicle screw. In addition, 14 pedicle screws were inserted in the axis. The mean follow-up period was 23 (range 8–38) months. No neurologic or vascular complications occurred in any of the seven patients. Postoperative CT three-dimensional reconstruction images showed that all 14 pedicle screws were inserted in the C1 pedicles without destruction of the atlas pedicle cortical bone. All patients demonstrated bony fusion 6 months postoperatively.Conclusion
If there is a medullary canal in the C1 pedicle, a 3.5- or 4.0-mm-diameter pedicle screw can be safely inserted into the atlas and C1 pedicle screw fixation can be performed without any impact on fixation stability and clinical efficacy, even if the C1 pedicle height is less than 4.0 mm. 相似文献12.
Yingsong Wang Jingming Xie Zhendong Yang Zhi Zhao Ying Zhang Tao Li Luping Liu 《Archives of orthopaedic and trauma surgery》2013,133(7):901-909
Purpose
To present the technique of free-hand subaxial cervical pedicle screw (CPS) placement without using intra-operative navigating devices, and to investigate the crucial factors for safe placement and avoidance of lateral pedicle wall perforation, by measuring and classifying perforations with postoperative computed tomography (CT) scan.Summary of background data
The placement of CPS has generally been considered as technically demanding and associated with considerable lateral wall perforation rate. For surgeons without access to navigation systems, experience of safe free-hand technique for subaxial CPS placement is especially valuable.Materials and methods
A total of 214 consecutive traumatic or degenerative patients with 1,024 CPS placement using the free-hand technique were enrolled. In the operative process, the lateral mass surface was decorticated. Then a small curette was used to identify the pedicle entrance by touching the cortical bone of the medial pedicle wall. It was crucial to keep the transverse angle and make appropriate adjustment with guidance of the resistance of the thick medial cortical bone. The hand drill should be redirected once soft tissue breach was palpated by a slim ball-tip prober. With proper trajectory, tapping, repeated palpation, the 26–30 mm screw could be placed. After the procedure, the transverse angle of CPS trajectory was measured, and perforation of the lateral wall was classified by CT scan: grade 1, perforation of pedicle wall by screw placement, with the external edge of screw deviating out of the lateral pedicle wall equal to or less than 2 mm and grade 2, critical perforation of pedicle wall by screw placement, large than 2 mm.Results
A total of 129 screws (12.64 %) were demonstrated as lateral pedicle wall perforation, of which 101 screws (9.86 %) were classified as grade 1, whereas 28 screws (2.73 %) as grade 2. Among the segments involved, C3 showed an obviously higher perforating rate than other (P < 0.05). The difference between the anatomical pedicle transverse angle and the screw trajectory angle was higher in patients of grade 2 perforation than the others. In the 28 screws of grade 2 perforation verified by axial CT, 26 screws had been palpated as abnormal during operation. However, only 19 out of the 101 screws of grade 1 perforation had shown palpation alarming signs during operation. The average follow-up was 36.8 months (range 5–65 months). There was no symptom and sign of neurovascular injuries. Two screws (0.20 %) were broken, and one screw (0.10 %) loosen.Conclusion
Placement of screw through a correct trajectory may lead to grade 1 perforation, which suggests transversal expansion and breakage of the thinner lateral cortex, probably caused by mismatching of the diameter of 3.5 mm screws and the tiny cancellous bone cavity of pedicle. Grade 1 perforation is deemed as relatively safe to the vertebral artery. Grade 2 perforation means obvious deviation of the trajectory angle of hand drill, which directly penetrates into the transverse foramen, and the risk of vertebral artery injury (VAI) or development of thrombi caused by the irregular blood flow would be much greater compared to grade 1 perforation. Moreover, there are two crucial maneuvers for increasing accuracy of screw placement: identifying the precise entry point using a curette or hand drill to touch the true entrance of the canal after decortication, and guiding CPS trajectory on axial plane by the resistant of thick medial wall. 相似文献13.
Feng Yuan Hui-Lin Yang Kai-Jin Guo Jiang-Shan Li Kai Xu Zhi-Ming Zhang Tian-Si Tang 《European spine journal》2013,22(1):39-45
Purpose
This anatomic, radiographic study investigated locational differences in the C2 pedicle and isthmus [pediculoisthmic component (PIC)] and characterized its narrowest section for clinical application in posterior C2 screw fixation.Methods
Structures surrounding the transverse foramina of 30 dry C2s and 10 C3s were compared morphologically. Spinal CT scans of 32 Chinese adults were subjected to volume rendering and multiplanar reconstruction to identify the narrowest C2 PIC, and correlative parameters were measured and analyzed.Results
Inferior C2 and C3 structures were morphologically similar. In superior view, the C2 superior facets lay on the transverse foramen and the upper portion between superior and inferior facets was flat (average mediolateral angle, 11.1° ± 2.4°). In inferior view, the posteroinferomedial portion of the C2 transverse foramen displayed a partially tubular structure (average mediolateral angle of projection, 42.6° ± 4.9°). Average height and width were 11.6 and 6.9 mm. The inner medullary cavity was elliptical and the middle site of endosteal diameter was 3.3 ± 1.9 mm. Medial internal cortical bone was significantly thicker than lateral bone (P < 0.01).Conclusions
The PIC is located between superior and inferior C2 facets. The superior flat area is the isthmus and the inferomedial area connecting the inferior facet and vertebral body is the pedicle. The pedicle is partially tubular and projects posteromedially to the transverse foramen. The narrowest PIC section is the narrowest point of the C2 pedicle. Considering its thin lateral cortical bone, medial and superior pedicle screw placement and preoperative CT reconstruction are recommended. 相似文献14.
Albrecht Waschke Jan Walter Pedro Duenisch Rupert Reichart Rolf Kalff Christian Ewald 《European spine journal》2013,22(3):654-660
Purpose
Single center evaluation of the placement accuracy of thoracolumbar pedicle screws implanted either with fluoroscopy or under CT-navigation using 3D-reconstruction and intraoperative computed tomography control of the screw position. There is in fact a huge variation in the reported placement accuracy of pedicle screws, especially concerning the screw placement under conventional fluoroscopy most notably due to the lack of the definition of screw misplacement, combined with a potpourri of postinstrumentation evaluation methods.Methods
The operation data of 1,006 patients operated on in our clinic between 1995 and 2005 is analyzed retrospectively. There were 2,422 screws placed with the help of CT-navigation compared to 2,002 screws placed under fluoroscopy. The postoperative computed tomography images were reviewed by a radiologist and an independent spine surgeon.Results
In the lumbar spine, the placement accuracy was 96.4 % for CT-navigated screws and 93.9 % for pedicle screws placed under fluoroscopy, respectively. This difference in accuracy was statistically significant (Fishers Exact Test, p = 0.001). The difference in accuracy became more impressing in the thoracic spine, with a placement accuracy of 95.5 % in the CT-navigation group, compared to 79.0 % accuracy in the fluoroscopy group (p < 0.001).Conclusion
This study underlines the relevance of CT-navigation-guided pedicle screw placement, especially when instrumentation of the middle and upper thoracic spine is carried out. 相似文献15.
Lamartina Claudio Cecchinato Riccardo Fekete Zsolt Lipari Alberto Fiechter Meinrad Berjano P. 《European spine journal》2015,24(7):937-941
Purpose
Pedicle screw placement is an increasingly common procedure for the correction of spine degenerative disease, deformity and trauma. However, screw placement is demanding, with complications resulting from inaccurate screw placement. While several different techniques have been developed to improve accuracy, they all have their limitations.Methods
We examined the MySpine (Medacta International SA, Castel San Pietro, CH) patient-matched pedicle targeting guide in three cadaveric spine specimens operated on by three surgeons. A three-dimensional (3D) preoperative plan was constructed from spinal computed tomography scans, from which individualised guides were developed for the placement of Medacta Unconstrained Screw Technology pedicle screws. Following screw placement, the 3D positioning of the screws was compared to the preoperative plan against a series of pre-defined criteria.Results
Of 46 inserted screws eligible for assessment, 91.3 % were fully inside the pedicle. There were no cases of Grade B (2–4 mm) or C (>4 mm) pedicle perforation. The mean deviation between the planned and actual screw position at the midpoint of the pedicle was 0.70 mm, the mean horizontal deviation was 0.60 mm and the mean vertical deviation was 0.77 mm. The mean angular deviation in the sagittal plane was 1.74°, versus 1.32° in the transverse plane. The mean deviation in screw depth was 1.55 mm. On all measures, the accuracy of screw placement was within the predefined criteria.Conclusions
Our cadaver study indicates that pedicle screw placement with the system is accurate and should be investigated in larger in vitro and in vivo studies.16.
17.
Background
The purpose of this study was to evaluate the accuracy of pedicle screw placement, its advantages, and limitations in posterior instrumentation of thoracolumbar and lumbar burst fractures assisted only by lateral fluoroscopic imaging.Materials and methods
Pre- and postoperative computerized tomographic (CT) scans of 117 patients with thoracolumbar and lumbar burst fractures, who underwent posterior instrumentation with pedicle screw fixation, were prospectively analyzed. Accuracy of screw placement, reconstruction of the vertebral height, and correction of the kyphotic angle were studied. Position of the pedicle screws were determined, and cortical breach was graded on the postoperative axial CT scans. Percentage of vertebral height reconstruction and kyphotic angle correction were calculated from the postoperative midsagittal CT scans.Results
Four hundred and sixty-eight pedicle screws in 234 motion segments were included in this study. 427 screws were centrally placed with an accuracy rate of 91.24%. Out of the 41 (8.76%) screws that breached the pedicle wall, 32 (6.84%) screws had violated the medial wall, while 9 (1.92%) screws breached the lateral wall. There were no “air-ball” screws. No screw penetrated the anterior wall. Postoperatively, none of the patients deteriorated neurologically, and no screw required revision. Postoperatively, there was significant restoration of vertebral height and correction of kyphosis (P < 0.05).Conclusion
Pedicle fixation performed on a Relton-Hall frame is relatively simple and, when performed carefully using only lateral fluoroscopic imaging, has a lower potential for complications due to cortical breach.18.
Sven Rainer Kantelhardt Naureen Keric Jens Conrad Amr Nimer Raymund Woo Laura Varich Alf Giese 《Acta neurochirurgica》2014,156(9):1799-1805
Background
Two-dimensional image guidance and navigation can help to reduce the number of misplaced pedicle screws, but do not completely prevent misplacement. This experimental, retrospective, non-inferiority study was designed to evaluate and compare the efficacy of a novel 3D imaging technique versus conventional postoperative CT-scan, for intra-operative determination of pedicle screw position accuracy.Methods
The capacity of C-OnSite® to intraoperatively assess screw placement was evaluated in 28 clinical cases and 23 deliberately misplaced screws in a cadaver model, and compared to placement accuracy determined by standard CT. The position of each implant, as viewed by both modalities, was graded by three neurosurgeons, one orthopaedic-surgeon and one radiologist. The intermodal variance determined the difference between CT- and C-OnSite® results for each observer, while the inter-observer variance measured the difference between ratings of the same modality by different observers.Results
C-OnSite® successfully assessed 120/138 screws (25/28 cases). Mean procedural fluoroscopy time was 132?±?51s, and 40?±?16s per C-OnSite® scan. The average inter-modality variance was ,15 % with mismatches >1° between C-OnSite® and the gold-standard imaging technique in only 2 % of the comparisons. Average inter-observer variances were about similar (12 % for CT and 18 % for C-OnSite®), with deviations of >1° reaching 1 % for CT and 3 % for C-OnSite®. Individual variances between experienced only observers differed even less.Conclusions
C-OnSite® is a feasible, reliable and intuitive means of intraoperatively visualizing pedicle screw positions and might render the majority of postoperative CTs superfluous. C-OnSite® might help avoid re-operations for screw re-positioning. 相似文献19.
Mengran Jin Zhen Liu Xingyong Liu Huang Yan Xiao Han Yong Qiu Zezhang Zhu 《European spine journal》2016,25(6):1729-1737
Purpose
To assess the accuracy of O-arm-navigation-based pedicle screw insertion in dystrophic scoliosis secondary to NF-1 and compare it with free-hand pedicle screw insertion technique.Methods
32 patients with dystrophic NF-1-associated scoliosis were divided into two groups. A total of 92 pedicle screws were implanted in apical region (two vertebrae above and below the apex each) in 13 patients using O-arm-based navigation (O-arm group), and 121 screws were implanted in 19 patients using free-hand technique (free-hand group). The postoperative CT images were reviewed and analyzed for pedicle violation. The screw penetration was divided into four grades: grade 0 (ideal placement), grade 1 (penetration <2 mm), grade 2 (penetration between 2 and 4 mm), and grade 3 (penetration >4 mm).Results
The accuracy rate of pedicle screw placement (grade 0, 1) was significantly higher in the O-arm group (79 %, 73/92) compared to 67 % (81/121) of the free-hand group (P = 0.045). Meanwhile, a significantly lower prevalence of grade 2–3 perforation was observed in the O-arm group (21 vs. 33 %, P < 0.05), and the incidence of medial perforation was significantly minimized by using O-arm navigation compared to free-hand technique (2 vs. 15 %, P < 0.01). Moreover, the implant density in apical region was significantly elevated by using O-arm navigation (58 vs. 42 %, P < 0.001).Conclusion
We reported 79 % accuracy of O-arm-based pedicle screw placement in dystrophic NF-1-associated scoliosis. O-arm navigation system does facilitate pedicle screw insertion in dystrophic NF-1-associated scoliosis, demonstrating superiorities in the safety and accuracy of pedicle screw placement in comparison with free-hand technique.20.
Mun Keong Kwan Chee Kidd Chiu Chris Yin Wei Chan Reza Zamani Nils Hansen-Algenstaedt 《European spine journal》2016,25(6):1745-1753