Segmental vertebral rotation in early scoliosis

Summary In order to investigate the development of the vertebral axial rotation in patients with early scoliosis, the vertebral rotation angle (VRA) was quantified on the basis of 132 anteroposterior radiographs obtained from patients with diagnosed or suspected scoliosis. The rotation was measured in the apical vertebra and in the two suprajacent and two subjacent vertebrae. The radiographic material was divided into a control reference group and three scoliotic groups with varying Cobb angle from 4° up to 30°. In the reference group a slight vertebral rotation was significantly more often seen to the right. In the scoliotic groups, the rotation was most pronounced in the apical segments. The mean VRA toward the convex side was significantly increased in the vertebrae just suprajacent to the apex in curves with a Cobb angle of 8°–15° and in the cranial four vetebrae in curves with a Cobb angle of 16°–30°. Atypical vertebral rotation to the opposite side of the major curve was observed in 12.8% of the cases. There was a significant positive correlation between the VRA and the Cobb angle. These results show that a slight VRA to the right is a common feature in the normal spine, and that the VRA increases with progressive lateral deviation of the spine. It is concluded that the coronal plane deformity in early idiopathic scoliosis is accompanied and probably coupled to vertebral rotation in the horizontal plane.     

Rotational hypermobility of disc wedging using kinematic CT: preliminary study to investigate the instability of discs in degenerated scoliosis in the lumbar spine

The number of patients showing lumbar degenerative scoliosis, including disc wedging, has increased, and examination of the mechanism of spinal nerve compression due to lateral and rotational mobility of the lumbar spine is necessary. Thirty-two patients with L4–L5 disc wedging but without antero- or retrospondylolisthesis and ten age-matched controls were examined. The angle of disc wedging and change in the angle between left and right bending were evaluated by anterior–posterior X-ray images of patients while they were in a standing position. The degree of disc degeneration and existence of vacuum phenomena were evaluated at the L4–L5 discs. Rotational mobility between maximal right and left rotation was examined by computed tomography (CT). Rotational mobility was measured using the spinal transverse processes of L4 and L5. The relationship between these factors was statistically evaluated using multivariate analysis and Spearman’s correlation test. There was a significant increase in the average rotational mobility of the L4–L5 disc-wedging group. In the L4–L5 disc-wedging group, the increased angle of disc wedging and change in the angle between left and right bending correlated with increased rotational mobility. The degree of disc degeneration did not affect rotational mobility. However, existence of vacuum phenomena increased the rotational mobility of the L4–L5 disc-wedging group. This is the first study to evaluate the rotational hypermobility of L4–L5 disc wedging in patients without antero- or retrospondylolisthesis using kinematic CT. Increases in the wedging angle and abnormal instability of lateral bending correlated with increased rotational mobility. For surgical planning of degenerative L4–L5 disc wedging, it is important to consider rotational hypermobility using kinematic CT or X-ray imaging findings of lateral bending.     

Measurement of spinal range of motion in healthy individuals using an electromagnetic tracking device

OBJECT: The authors measured the range of motion (ROM) of the spine in healthy individuals by using an electromagnetic tracking device to evaluate the functional performance of the spine. METHODS: The authors used the Flock of Birds electromagnetic tracking device with 4 receiver units attached to C-7, T-12, S-1, and the midthigh region. Forward/backward bending, bilateral side bending, and axial rotation of the trunk were performed in 18 healthy individuals. RESULTS: The average ROM was calculated after 3 consecutive measurements. The thoracic spine generated the greatest angle in axial rotation and smallest angle in backward bending. The lumbar spine generated the greatest angle in forward bending and smallest angle in axial rotation. The hip joints generated the greatest angle in forward bending and smallest angle in backward bending. Additionally, 40% of forward-bending motion occurred in the lumbar spine and 40% occurred in the hip joints. Approximately 60% of backward bending occurred in the lumbar spine; 60% of axial rotation occurred in the thoracic spine; and 45% of side bending occurred in the thoracic spine. CONCLUSIONS: The Flock of Birds electromagnetic tracking device cannot only measure the ROM of spine but also easily differentiate the 6-degree contributions by different segments.     

Comparative analysis of pedicle screw versus hybrid instrumentation in adolescent idiopathic scoliosis surgery

The expectations of both the patient and surgeon have been greatly revised in the last 10 years with the introduction of pedicle screws (PS) in spinal surgery. In this study, we have retrospectively evaluated and compared the results of PS instrumentation and the Hybrid System (HS), the latter consists of pedicle screws, sublaminar wire and hooks. The mean follow-up period was 60.1 months (range: 49-94 months) for the patients of the HS group and 29.3 months (range: 24-35 months) for those of the PS group. In the HS group, pedicle screws were used at the thoracolumbar junction and lumbar vertebra, the bilateral pediculotransverse claw hook configuration was used at the cranial end of the instrumentation, sublaminar wire was used on the concave side of the apical region and the compressive hook was used on the convex side. In the PS group, PS were used on the concave sides at all levels and on the convex side of the cranial and caudal end of instrumentation, in the transition zone and at the apex. The two groups were comparable for variables such as mean age, preoperative Cobb angle, thoracic kyphosis angle, lordosis angle, coronal balance, flexibility of the curve, apical vertebra rotation (AVR), apical vertebra rotation (AVT) and the number of vertebrae included in the fusion (p > 0.05). The parameters of values of correction, ratio of correction loss, AV derotation, AVT correction ratio, amount of blood loss, operation time, postoperative global coronal and sagittal balance, thoracic kyphosis angle and lumbar lordosis angle were measured at the last follow-up and used for comparing the HS and PS groups. There was no statistically significant difference between the groups for correction ratio, postoperative coronal balance, postoperative thoracic kyphosis and lumbar lordosis angle, operation time, amount of blood loss and number of fixation points (p > 0.05) The difference for the ratio of correction loss, AV derotation angle and the AVT correction ratio at the last follow-up visit and for the total follow-up period between the groups was found to be statistically significant (p < 0.05). Although it is possible to obtain a similar amount of correction by either instrumentation system, the loss of correction seems to be lower with the more rigid PS construction. The PS system also has a stronger effect on vertebral bodies, thereby providing better AV de-rotation. There was no significant difference (p > 0.05) between the groups in terms of correction rate, postoperative coronal and sagittal balance, operation time, blood loss and number of fixation points. This may indicate that anchor points are more important than the use - or not - of screws. Correction durability and AV de-rotation was better with PS instrumentation, while AVT was better corrected by HS instrumentation (p < 0.05). We propose that the reason for the better correction of AVT with HS instrumentation is the forceful translation offered by the sublaminar wire at the apical region, while the reason for the better correction durability of the PS instrumentation may be due to the fact that multiple pedicle screws which afford three-column control are better at maintaining the correction and preventing late deterioration.     

退行性腰椎侧凸椎旁肌横截面积和脂肪化程度的变化及临床意义

目的 探讨退行性腰椎侧凸(DLS)椎旁肌横截面积和脂肪化程度的变化及其临床意义.方法 纳入2018年9月—2020年3月遂宁市第一人民医院收治的70例DLS患者作为研究组,同期70名健康体检者作为对照组,均进行腰椎X线片、MRI检查.比较2组患者的腰椎前凸角(LL)、腰椎冠状位侧凸Cobb角、腰椎顶锥旋转畸形分级、椎旁...     

成人腰椎侧凸椎弓根螺钉误置模式

目的探讨成人腰椎侧凸椎弓根螺钉误置模式并分析其危险因素。方法选取2010年8月至2011年6月行后路全椎弓根螺钉固定的成人腰椎侧凸患者49例,男14例,女35例;年龄30～65岁,平均39．2±13．8岁。术中根据解剖标志徒手置入椎弓根螺钉,术后行CT检查。破壁螺钉按测量螺钉穿破椎弓根内、外侧壁及椎体前缘的距离分为4级：1级≤2mm,2级2．1—4．0mm,3级4．1～6．0mm,4级≥6．1mm。不良置钉为穿透任一壁距离超过2mm者,高危置钉为穿破内侧壁超过4mm或穿破外侧壁顶尖使主动脉变形者。比较不同分组螺钉破壁率的差异。结果49例共置入353枚螺钉,平均每例7．2枚。螺钉完全在椎弓根内且无椎体前缘穿破316枚（占89．5％）。破壁螺钉37枚（占10．5％）,根据破壁距离分级：1级25枚,2级8枚,3级1枚,4级3枚。不良置钉12枚（占3．4％）,其中穿破内、外侧壁及椎体前缘超过2mm分别为3枚、6枚、3枚。无高危置钉。螺钉破壁率：年龄〉50岁组为9．9％与年龄≤50岁组为10．9％无显著性差异（P=0．860）;顶椎（apicalvertebra,AV）高于AV上下各节段;凹侧为15．6％明显高于凸侧为5．9％（P=0．005）;Cobb角〉60°组为20．2％显著高于Cobb角≤60。组为6．1％（P〈0．001）。椎体旋转3—4度组为16．5％明显高于椎体旋转0～2度组为6．5％（P=0．012）。患者术中及术后均未出现神经并发症。结论成人腰椎侧凸椎弓根螺钉置人具有较高的精确性,破壁螺钉及不良置钉主要位于AV及凹侧,危险因素包括较大Cobb角、严重椎体旋转以及凹侧置钉。     

Biomechanical evaluation of stand-alone lumbar polyether-ether-ketone interbody cage with integrated screws

Background contextStand-alone interbody cages with integrated screws potentially provide a biomechanically stable solution for anterior lumbar interbody fusion (ALIF) that alleviates the need for additional exposure for supplemental fixation, thereby reducing the chance of additional complications and morbidity.PurposeTo compare the stability of a stand-alone anterior interbody fusion system with integrated fixation screws against traditional supplemental fixation methods and to evaluate the difference between three and four fixation screws in the stand-alone cage.Study designIn vitro cadaveric biomechanical study.MethodsEight cadaveric lumbar spines (L2–sacrum) were tested using a flexibility protocol consisting of three cycles to ±7.5 Nm in flexion-extension, lateral bending, and axial rotation. The conditions evaluated were intact spine; polyether-ether-ketone cage (zero integrated screws) at L4–L5; cage (zero screws)+bilateral pedicle screws (PS); cage (three screws); cage (four screws); cage (zero screws)+anterior plate; and cage (three screws)+spinous process plate. Motion at the index level was assessed using an optoelectronic system.ResultsThe cage without integrated screws reduced the motion in flexion-extension and lateral bending (p<.001) compared with that in the intact spine. In axial rotation, mean range of motion (ROM) was 8% greater than in intact spine (p>.962). The addition of three integrated screws reduced ROM significantly compared with the cage without screws in all motion planes (p<.001). A fourth screw had no statistically significant effect on the ROM, although there was a trend toward less motion with four screws compared with three. In flexion-extension, the cage with three integrated screws and the spinous process plate was the most rigid condition. There was no significant difference from the bilateral PS (p=.537); however, this was more rigid than all other conditions (p<.024). The most stable condition in lateral bending and axial rotation was the cage with bilateral PS. In lateral bending, the cage (three or four screws) was not significantly different from the cage with anterior plate or the cage (three screws) with spinous process plate fixation; however, only the latter condition was statistically comparable with bilateral PS. In axial rotation, there were no significant differences between the conditions that included integrated screws or supplemental fixation (p>.081).ConclusionsBiomechanical testing revealed that the stand-alone cage with integrated screws provides more immediate stability than a cage alone and provides equivalent stability to ALIF constructs with supplemental fixation in lateral bending and axial rotation. Additional flexion-extension rigidity of the anterior cage maybe realized by the addition of a spinous process plate that was found to be as stable as supplemental bilateral PS.     

School screening for scoliosis: the value of quantitative measurement

Summary Several studies advocate quantification of the bending test or performing surface topography to reduce the referral rate and to increase the specificity of the bending test in screening for scoliosis. Within the framework of a school screening project all children with a positive bending test were reexamined with measurement of rib hump height, angle of trunk rotation and moiré topography. In the period 1983–1986, out of three cohorts of 10 000 children of 10, 12 and 14 years of age, 3069 were reexamined, of whom 1931 again tested positive (63%). The value of the three techniques in terms of sensitivity and specificity within the reexamined group was evaluated with regard to the Cobb angle on a spinal radiograph, which was made in 671 cases. A reduction in referrals of 37% was found. No significant difference in the ability to detect scoliosis was found between the three techniques mentioned. It is concluded that measurement techniques are valuable in school screening programmes. In particular, if instead of a single cut-off value, a range within which the examination should be repeated is chosen, high sensitivity and high specificity can be combined. Angle of trunk rotation measurement seems to be the easiest method of screening.We regret to inform the reader of the death of W. Keessen on 4 December 1993.     

单平面椎弓根螺钉矫正Lenke 5型青少年特发性脊柱侧凸顶椎旋转

目的对单平面椎弓根螺钉和万向椎弓根螺钉矫正Lenke 5型青少年特发性脊柱侧凸(AIS)顶椎旋转的效果进行对比分析。方法回顾性分析2010年1月—2013年12月收治的72例应用万向/单平面椎弓根螺钉行后路三维矫形植骨融合内固定术的Lenke 5型AIS患者的临床资料,其中使用万向椎弓根螺钉治疗(A组)43例,使用单平面椎弓根螺钉治疗(B组)29例。记录手术前后腰椎侧凸Cobb角和腰椎前凸角,并计算侧凸矫正率。术前使用Nash-Moe法评估顶椎旋转程度,术后根据Upasani等提出的X线椎体旋转分级标准评价顶椎去旋转的效果。结果所有患者均顺利完成手术。2组患者术前侧凸Cobb角及腰椎前凸角差异无统计学意义(P 0.05);2组术后2周及1年侧凸Cobb角及腰椎前凸角均较术前显著改善,差异有统计学意义(P 0.05);A组术后1年侧凸矫正率为79.2%,B组为81.4%,差异无统计学意义(P 0.05)。2组患者术前顶椎旋转程度差异无统计学意义(P 0.05);术后2周及1年顶椎去旋转程度B组优于A组,差异有统计学意义(P 0.05)。结论两种椎弓根螺钉都能很好地矫正Lenke 5型AIS患者冠状面侧凸,单平面椎弓根螺钉在矫正及维持顶椎去旋转效果方面优于万向椎弓根螺钉。     

Differential rod contouring on thoracolumbar/lumbar curvature in patients with adolescent idiopathic scoliosis: An analysis with intraoperative acquisition of three-dimensional imaging

BackgroundDifferential rod contouring (DRC) is useful for periapical vertebral derotation and decreasing rib hump in patients with thoracic adolescent idiopathic scoliosis (AIS). However, it is unknown whether DRC in the thoracolumbar/lumbar spine also contributes to derotation. We assessed the contributions of rod contouring and of DRC to the reduction of apical axial vertebral body rotation in patients with AIS with thoracolumbar/lumbar curvatures.MethodsForty-five (Lenke type 3 or 4, 17; Lenke type 5 or 6, 28) were analyzed for the contribution of DRC to thoracolumbar/lumbar spinal derotation. Rod contouring was assessed by comparing the preinsertion x-ray with the post-operative CT images. Intraoperative C-arm fluoroscopic scans of the periapical vertebrae of the thoracolumbar/lumbar curve of the scoliosis (135 vertebrae) were taken post-rod rotation (RR) and post-DRC in all patients. Three-dimensional images were automatically reconstructed from the taken x-ray images. The angle of vertebral body rotation in these apical vertebrae was measured, and the contribution of DRC to apical vertebral body derotation and rib hump index (RHi) for lumbar prominence was analyzed.ResultsThe pre-implantation convex rod curvatures of both Lenke 3/4 and 5/6 groups decreased after surgery. The mean further reductions in vertebral rotation with post-RR DRC were 3.7° for Lenke 3/4 and 4.4° for Lenke 5/6 (P < 0.01). Both changes in apical vertebral rotation and in RHi for evaluating lumbar prominence were significantly correlated with the difference between concave and convex rod curvature in preimplantation. Vertebral derotation was significantly higher in curves with a difference >20° (P < 0.05).ConclusionsDRC following rod rotation contributed substantial additional benefit to reducing vertebral rotation and decreasing lumbar prominence in thoracolumbar/lumbar scoliosis.     

Trunk rotation in scoliosis the influence of curve type and direction in 150 children

We compared the angle of trunk rotation (ATR) from scoliometer readings with Cobb angle measurements of the lateral deviation of the spine in 150 children referred to hospital for evaluation of scoliosis. the mean Cobb angle in thoracic curves was 16 °, in thoracolumbar curves 17° and in lumbar curves 20°. in thoracic curves and in right convex curves no patient with a Cobb angle of 25° or more had an ATR below 9°. in thoracolumbar and lumbar and in left convex curves, 7° ATR was occasionally associated with scoliosis of 25° or more. the correlation coefficient between the ATR and Cobb angle in right convex curves was 0.65 compared to 0.57 in left convex curves. We conclude that a criterion of 7° ATR for thoracic or right convex curves and one of 6° ATR for thoracolumbar and lumbar or left convex curves seem adequate for identification of patients with Cobb angles of 25° or more, which reduces the need for spinal radiography and follow-up outside the school screening programs.     

Placement of pedicle screws using three-dimensional fluoroscopy-based navigation in lumbar vertebrae with axial rotation

Despite potential advantages of three-dimensional fluoroscopy-based navigation, there still remain a lot of controversies about the indications of this technology, especially whether it is worthy of being used in placement of pedicle screws in lumbar spine. However, according to the inconsistent conclusions reported in the literature and our experiences, the traditional method relying on anatomical landmarks and fluoroscopic views to guide lumbar pedicle screw insertion is unable to meet the requirement of precise screw placement. Based on our observation, screw malposition seems to occur concomitant with vertebral axial rotation which is a ubiquitous phenomenon. Three-dimensional fluoroscopy-based navigation can provide the most valuable axial images in real-time, so it may be useful for placement of pedicle screws in lumbar spine. This study was intended to evaluate the effect of axial rotation of lumbar vertebrae on the accuracy of pedicle screw placement using the traditional method, as well as assess the value of three-dimensional fluoroscopy-based navigation in improving the accuracy. Sixteen lumbar simulation models at different degrees of axial rotation (0°, 5°, 10°, and 20°), with every four assigned the same degree, were equally divided into two groups (traditional method group and three-dimensional fluoroscopy-based navigation group). Random placement of pedicle screws was carried out, followed by CT scan postoperatively. Then the outer pedicle cortex contours were depicted from reconstructed sectional pedicle images using Photoshop. The accuracy of pedicle screw placement was evaluated by determining the interrelationship between screw trajectory and pedicle cortex (quality), and measuring the shortest distance from pedicle screw axis to outer cortex of the pedicle (quantity). Eighty pedicle screws were implanted, respectively, in each group. In traditional method group, statistical difference existed in the accuracy of pedicle screw placement at different axial rotational degrees (P < 0.05). With degrees increasing, the accuracy declined. The accuracy of three-dimensional fluoroscopy-based navigation group was higher than traditional method group in vertebrae with axial rotation (P < 0.01). In qualitative evaluation, the accuracy of the two methods had statistical difference when the degree was 20°, and in quantitative evaluation, statistical difference existed in 5°, 10°, and 20° of vertebral axial rotation.     

Which posterior instrumentation is better for two-level anterior lumbar interbody fusion: translaminar facet screw or pedicle screw?

Purpose

To determine whether translaminar facet screws can provide stability equivalent to pedicle screws and whether the two posterior instrumentations have the same influence on the adjacent segments in two-level anterior lumbar interbody fusion.

Methods

In a biomechanical study conducted, we used 12 fresh human lumbar spines and tested an intact spine with a stand-alone two-level anterior lumbar interbody fusion and anterior fusion augmented with pedicle screws or translaminar facet screws, under 400 N compressive preloads and 7.5 N m moments in flexion, extension, axial rotation and lateral bending, and measured the stiffness of the operated level, range of motion and intradiscal pressure at the adjacent levels.

Results

We found a significant increase in the stiffness of the segments operated, range of motion and intradiscal pressure at the adjacent superior segment in the stand-alone two-level anterior lumbar interbody fusion during flexion, axial rotation and lateral bending, but a decrease in extension, when compared with the intact spine. The stiffness of operated segments, range of motion and intradiscal pressure in the adjacent segment are significantly higher in the two-level anterior lumbar interbody fusion augmented with posterior instrumentation than in the stand-alone two-level anterior lumbar interbody fusion. There was no significant difference between the two augmented constructs except that, at the adjacent superior segment, the intradiscal pressure was more in the construction augmented with a pedicle screw than with a translaminar facet screw in flexion.

Conclusions

Translaminar facet screws can provide stability equivalent to pedicle screws, but their influence on the adjacent segments is relatively lower; therefore, we suggest that translaminar facet screws be the choice in the optimal posterior instrumentation in a two-level anterior lumbar interbody fusion.     

Maintenance of Derotation in Adolescent Idiopathic Scoliosis: a Novel Technique Measuring Postoperative Vertebral Rotation by Pedicle Screw Position

Background

Current methods of measuring vertebral rotation by plain radiographs rely on anatomic landmarks that are not present in the postoperative spine or require advanced imaging. Furthermore, there are few studies on the incidence of crankshaft with modern pedicle instrumentation.

Questions/Purposes

We sought to (1) describe and validate a method of vertebral rotation measurement using plain radiographs and (2) measure postoperative rotation in a series of patients treated for adolescent idiopathic scoliosis.

Methods

Patients with adolescent idiopathic scoliosis treated with surgery over a 6-year period were reviewed. Patients with computed tomography (CT) scans and radiographs within 60 days of another were included. Vertebral rotation was calculated by radiographic measurements and measured directly by CT scan. As an internal control, patients with two apical pedicle screws on all radiographs were analyzed. Rotation was measured for all patients with at least 1 year of radiographic follow-up.

Results

Three thousand five hundred fifty-two instrumented spinal levels in 308 consecutive patients were reviewed. Ten patients with 93 screws were analyzed by CT and radiographs. The average discrepancy between computed tomography (CT) and radiographs was 3.3?±?1.9°, with 81.7% (76/93) within 5°. Intra- and inter-rater reliabilities for measured axial rotation were excellent (intra-class correlation coefficient (ICC)?=?0.879 and 0.900, respectively). One hundred swventy-eight patients were eligible with an average follow-up of 2.3?±?1.2 years; 84.8% (151/178) had screw(s) visible on all images at the major curve apex. The average postsurgical rotation was 3.5?±?2.9°; 19.2% (29/151) were measured to have a rotation over 5°, and 4.0% (6/151) demonstrated a rotation over 10°. Only 4.6% (7/151) of patients demonstrated a postoperative Cobb angle change over 10°.

Conclusions

Most major curves have apical pedicle screw instrumentation that can be followed by radiographs alone to measure rotation. Vertebral rotation measurement requires only plain radiographs and is a more sensitive determination for subtle postoperative crankshaft than change in Cobb angle.

     

Correction of flexible thoracic scoliosis below 65 degrees—A radiological comparison of anterior versus posterior segmental instrumentation applied to similar curves

Direct comparison of the correction of scoliosis achieved by different surgical methods is usually limited by the heterogeneity of the patients analyzed (their age, curve pattern, curve magnitude, etc.). The hypothesis is that an analysis of comparable scoliotic curves treated by different implant systems could detect subtle differences in outcome. The objective of this study was therefore: (1) to measure the 3D radiological parameters of scoliotic deformity and to quantify their postoperative changes, and (2) to compare the radiographic results achieved with one anterior and one posterior instrumentation methods applied to similar curves but representing different mechanisms of correction. Material and methods: The clinical notes and radiographs of 46 patients operated on for adolescent idiopathic scoliosis were reviewed. The inclusion criteria consisted of: a single thoracic curve, right convex, a frontal Cobb angle minimum of 45° and a maximum of 65°, flexibility on a lateral bending test of more than 30%, and a Risser test value of between 1 and 4. The operative procedures were: Cotrel-Dubousset instrumentation (CDI) for 25 patients (the CD group) and correction by anterior instrumentation (Pouliquen plate) for 21 patients (the ANT group). Preoperative and postoperative long cassette standing antero-posterior and lateral radiographs were examined. The frontal and sagittal thoracic Cobb angle, apical vertebra transposition (AVT), apical vertebra rotation (AVR), lowest instrumented vertebra (LIV) tilt, C7 vertebra shift and rib cage shift (RCS) were all compared. A computed reconstruction was produced with Rachis-91 software. Vertebral axial rotation angle was evaluated throughout the spine. Results: Postoperative assessment revealed a mean correction of the frontal Cobb angle of 37.0° for the CD group and 41.0° for the ANT group. The AVT operative correction was 45.8 and 42.7 mm, respectively, and AVR correction was 1.8 and 12.6°, respectively. The postoperative change of the sagittal Th4–Th12 Cobb angle was not significant for any method but it was significant (P=0.05) for the CD group if the curves were divided preoperatively into hypokyphotic and normokyphotic subgroups and then analyzed separately. Computed assessment demonstrated a correction of segmental axial rotation of more than 50% in the main thoracic curve in the ANT group, significantly more than that in the CD group (P<0.001). Conclusions: Anterior instrumentation provided better correction of the vertebral axial rotation and of the rib hump. CD instrumentation was more powerful in translation and more specifically addressed the sagittal plane: the postoperative thoracic kyphosis angle increased in the hypokyphotic curves and slightly decreased in the normokyphotic curves.     

Circumferential fusion by posterior approach in lumbosacral instability with or without pedicle screw fixation: a comparison of methods

Lumbosacral circumferential fusion, a method which is widely adopted for the treatment of the different causes of lumbar pain, may be carried out in a single stage by posterior approach, associating interbody fusion with cages with posterolateral fusion. During the same operation, pedicle screw fixation may also be performed. In order to evaluate the need for this final surgical stage represented by pedicle screws, a comparison was conducted in 2 groups of patients affected with lumbosacral instability, treated at the Division of Vertebral Surgery at the Rizzoli Orthopaedic Institute between May 1995 and May 1997. The best clinical results were obtained in the first group (where pedicle fixation was associated). Because of the persistance of pain symptoms, successive pedicle fixation was instead required in a high percentage of patients (45%) in the second group (without pedicle fixation).     

The change in ratio of convex and concave lung volume in adolescent idiopathic scoliosis: a 3D CT scan based cross sectional study of effect of severity of curve on convex and concave lung volumes in 99 cases

To study the effect of the degree of scoliosis, degree of hypokyphosis/lordosis and rotation of apical vertebra on individual lung volume (measured with CT scan) in asymptomatic adolescent idiopathic scoliosis (AIS) patients. Individual (right and left) lung volume, angle of kyphosis and rotation of apical vertebra, were measured in 77 asymptomatic AIS patients having right thoracic curve, using modern computed tomography (CT) scan. To compare, lung volumes were measured in 22 normal persons (control group). The ratio of “right to left lung volume (convex to concave side)” was obtained and compared among these groups. With increased Cobb’s angle, ratio of convex to concave lung volume increased. For Cobb’s angle more than 40°, it was increased significantly (P = 0.0042). A significant degree of correlation was found between axial rotation angle of apical vertebra and right to left lung volume ratio (P = 0.0067, r = 0.271). A significant inverse correlation was found between the angle of kyphosis and right to left lung volume ratio, i.e., as the angle of kyphosis decreased the convex to concave lung volume ratio increased (P = 0.0109, r = −0.255). In asymptomatic, AIS patients, with increase in degree of curvature, and rotation of apical vertebra, the ratio of convex to concave side lung volume increases; indicating concave side lung volume is comparatively more affected (decreased) than convex side lung volume. On the other hand with decrease in the angle of kyphosis the convex to concave lung volume ratio increases indicating kyphotic angle has an inverse relation to convex to concave lung volume ratio. An erratum to this article can be found at     

Minimally invasive technique of monoaxial percutaneous screws and instrumentational maneuvers in thoracolumbar and lumbar fractures

ObjectivesPercutaneous pedicle screw fixation (PPSF) has been a common surgery for treating thoracolumbar and lumbar fractures. Many studies have reported PPSF is associated with poor reduction. We present a reliable method by using short-segment monoaxial percutaneous screws and instrumentational maneuvers to reduce the spine. This study aimed to evaluate radiological and clinical results of this method of reduction compared to traditional polyaxial screws method in treating thoracolumbar and lumbar fractures.MethodsFrom February 2015 to February 2021, 64 patients with thoracolumbar and lumbar fractures in our department were retrospectively reviewed and divided into experimental group and control group according to different treatment methods. The experimental group was treated with short-segment monoaxial percutaneous screws (which were inserted at the adjacent vertebrae one level above, one level below the fracture, and the fractured vertebra) and instrumentational maneuvers method, while the control group was treated with traditional polyaxial screws method. The operation time was recorded. Visual analogue scale (VAS) and Oswestry disability index (ODI) were assessed as the clinical outcomes. The anterior height of the injured vertebra (AVH), the kyphosis cobb angle and the vertebral wedge angle were used to evaluate the fracture radiological reduction.ResultsA total of 64 patients were enrolled including 31 in the experimental group and 33 in the control group. There were no significant difference in operation time, AVH, the kyphosis cobb angle,the wedge angle of injured vertebra,VAS and ODI score between the two groups in preoperation. In each group, there were significant differences in the AVH, the kyphosis cobb angle and wedge angle of injured vertebra between preoperation and immediate postoperation. In each group, there were significant differences in VAS and ODI score between the preoperation and last follow-up. The total correction rates of AVH,the kyphosis cobb angle and the wedge angle of injured vertebra were significantly higher in the experimental group than those in the control group, while the loss of correction was significantly lower than the control.ConclusionsThe reduction technique using monoaxial percutaneous screws and instrumentational maneuvers for thoracolumbar and lumbar fractures exhibited better radiological results and satisfying functional outcomes when compared to traditional polyaxial screws.     

Measurement of vertebral rotation: Perdriolle versus Raimondi

Summary The measurement of vertebral rotation according to Perdriolle is widely used in the French-speaking and Anglo-American countries. Even in this measurement technique there may be a relatively high estimation error because of the not very accurate grading in steps of 5°. The measurement according to Raimondi seems to be easier to use and is more accurate, with 2° steps. The purpose of our study was to determine the technical error of both measuring methods. The apex vertebra of 40 curves on 20 anteroposterior (AP) radiographs were measured by using the Perdriolle torsion meter and the Regolo Raimondi. Interrater and intrarater reliability were computed. The thoracic Cobb angle was 43°, the lumbar Cobb angle 36°. The average rotation according to Perdriolle was 19.1° thoracic (SD 11.14), 12.7° lumbar (11.21). Measurement of vertebral rotation according to Raimondi showed an average rotation of 20.25° in the thoracic region (11.40) and 13.4° lumbar (10.92). The intrarater reliability was r=0.991 (Perdriolle) and r=0.997 (Raimondi). The average intrarater error was 1.025° in the Perdriolle measurement and 0.4° in the Raimondi measurement. Interrater error was on average 3.112° for the Perdriolle measurement and 3.630° for the Raimondi measurement. This shows that both methods are useful tools for the follow-up of vertebral rotation as projected on standard X-rays for the experienced clinicial. The Raimondi ruler is easier to use and is slightly more reliable.     

数字建模分析倒退旋转法在腰椎椎体单侧穿刺椎体后凸成形术的适用性

目的:利用Mimics软件建立腰椎的3D模型,使用模拟穿刺来观察倒退旋转法在腰椎椎体单侧穿刺椎体后凸成形术的适用性及进针参数。方法:选取24例全腰椎螺旋CT扫描初次胸椎骨质疏松性骨折、腰椎无异常骨质破坏的影像学资料,其中男女各12例,应用Mimics软件对原始DICOM文件进行3D建模,分离出各节段椎体,直接导入3-matic软件后约束其椎体后壁进行标准化测量后以椎弓根中点作一垂直于中切面及椎体后壁的素描图,在素描图上进行模拟穿刺,记录穿刺针可活动范围的角度参数及距离参数,记录穿刺针在最大外倾角时落在椎体中切线前、中、后区的穿越点,并进行比较分析。结果:所有数据在左右两侧差异均无统计学意义(P0.05),不同节段数据在两性差异有统计学意义(P0.05),男女性L_1-L_5最大外倾角均逐渐增大,男性从(33.41±1.31)°到(56.53±4.71)°,女性从(28.58±2.55)°到(53.86±2.68)°,所有穿越点未落在前区,其中女性26.67%落在中区,男性3.33%落在中区,A、B、C分区在性别上差异有统计学意义(P0.05)。结论:倒退旋转法理论上均能满足椎体压缩性骨折对穿刺点的要求,其中男性及下腰椎更加适用倒退旋转法。最大外倾角的测定对倒退旋转法有指导性意义。