scholarly journals Change in pelvic sagittal tilt after corrective long fusion of spine

10.29007/k35m ◽  
2018 ◽  
Author(s):  
Kazunori Tamura ◽  
Hidetoshi Hamada ◽  
Masaki Takao ◽  
Takashi Sakai ◽  
Takashi Kaito ◽  
...  

The individual pelvic sagittal inclination (PSI) is an issue for cup alignment in total hip arthroplasty (THA). The pelvic position in supine or functional pelvic plane in supine have been recommended by many reports while some consider a standing pelvic position as the reference to aim an optimal cup alignment. PSI changes in various postures and even in the same posture, aging change it due to spinal degeneration and muscle weakness. The chronological PSI change is larger in standing than that in supine. It is expected that PSI in standing position may improve when spinal long fusion was performed.Therefore, the purpose of this study was to evaluate the change of PSI between pre- and post- corrective long fusion for adult spinal deformity (ASD). Total eight patients underwent corrective surgery for ASD between May 2014 and October 2016 were the subjects of this study. All are females with the average age of 70 years. There were two cases that underwent bilateral THA before spine surgery. The anterior pelvic plane (APP) through the most anterior aspect of the pubic tubercle and bilateral anterior superior iliac spines (ASISs) was used to measure PSI, which was defined as the angle between the APP and the vertical axis on the sagittal plane DRR. In addition, we measured the cup anteversion in two THA cases by using viewer software. The mean change in the preoperative PSI from supine to standing was 17° posteriorly. The mean change in the supine PSI from pre- to post-operation was 6.9° anteriorly, and that in the standing PSI was 17° anteriorly. The mean change in the postoperative PSI from supine to standing was 6.7° posteriorly. When we measured PSI on standard AP radiographs of the pelvis in two patients who underwent THA, the mean change in postoperative PSI from supine to standing was less than 3°.The mean change in cup anteversion on supine AP radiographs were 2.7°. As we expected, the change in PSI from supine to standing position was reduced by performing corrective surgery. In this study, the mean change of radiographic cup anteversion in supine after corrective long fusion was 2.7°and PSI in standing changed into the direction which reduce posterior impingement and anterior dislocation. Although the change in PSI after corrective spine surgery heavily depends on the spine surgeon’s philosophy of correction, corrective spine surgery should have a positive effect on cup alignment in standing and little influence on cup alignment in supine.

2020 ◽  
pp. 1-8
Author(s):  
Hiroshi Moridaira ◽  
Satoshi Inami ◽  
Daisaku Takeuchi ◽  
Haruki Ueda ◽  
Hiromichi Aoki ◽  
...  

OBJECTIVEIssues with spinopelvic fixation for adult spinal deformity (ASD) include loss of the physiological mobility of the entire lumbar spine, perioperative complications, and medical costs. Little is known about the factors associated with successful short fusion for ASD. The authors evaluated radiographic and clinical outcomes after shorter fusion for different subtypes of ASD at 2 years postoperatively and examined factors associated with successful short fusion.METHODSThis was a single-center study of 37 patients who underwent short fusion and a minimum 2 years of follow-up for ASD in which lumbar kyphosis was the main deformity. The exclusion criteria were 1) age < 40 years, 2) previous lumbar vertebral fracture, 3) severe osteoporosis, 4) T10–L2 kyphosis > 20°, 5) scoliotic deformity with an upper end vertebra (UEV) above T12, and 6) concomitant Parkinson’s disease or neurological disease. The surgical procedures, radiographic course, and Oswestry Disability Index (ODI) were assessed, and correlations between radiographic parameters and postoperative ODI at 2 years were analyzed.RESULTSA mean of 3.5 levels were fused. The mean radiographic parameters preoperatively, at 2 weeks, and at 2 years, respectively, were as follows: coronal Cobb angle: 22.9°, 11.5°, and 12.6°; lumbar lordosis (LL): 12.9°, 35.8°, and 32.2°; pelvic incidence (PI) minus LL: 35.5°, 14.7°, and 19.2°; pelvic tilt: 29.4°, 23.1°, and 25.0°; and sagittal vertical axis 85.3, 36.7, and 59.2 mm. Abnormal proximal junctional kyphosis occurred in 8 cases. Revision surgery was performed to extend the length of fusion from a lower thoracic vertebra to the pelvis in 2 cases. The mean ODI scores preoperatively and at 2 years were 50.7% and 24.1%, respectively. Patient age, number of fused intervertebral segments, and radiographic parameters were analyzed by the stepwise method to identify factors contributing to the ODI score at 2 years, preoperative PI, and sagittal vertical axis at 2 years. On receiver operating characteristic curve analysis of the minimal clinically important difference of ODI (15%) and preoperative PI, the cutoff value of the preoperative PI was 47° (area under the curve 0.75).CONCLUSIONSIn terms of subtypes of ASD in which lumbar kyphosis is the main deformity, if the PI is < 47°, then the use of short fusion preserving mobile intervertebral segments can produce adequate LL for the PI, improving both postoperative global spinal alignment and quality of life.


2017 ◽  
Vol 26 (5) ◽  
pp. 638-644 ◽  
Author(s):  
Young-Seop Park ◽  
Seung-Jae Hyun ◽  
Ho Yong Choi ◽  
Ki-Jeong Kim ◽  
Tae-Ahn Jahng

OBJECTIVEThe aim of this study was to investigate the risk of upper instrumented vertebra (UIV) fractures associated with UIV screw fixation (unicortical vs bicortical) and polymethylmethacrylate (PMMA) augmentation after adult spinal deformity surgery.METHODSA single-center, single-surgeon consecutive series of adult patients who underwent lumbar fusion for ≥ 4 levels (that is, the lower instrumented vertebra at the sacrum or pelvis and the UIV of the thoracolumbar spine [T9–L2]) were retrospectively reviewed. Age, sex, follow-up duration, sagittal UIV angle immediately postoperatively including several balance-related parameters (lumbar lordosis [LL], pelvic incidence, and sagittal vertical axis), bone mineral density, UIV screw fixation type, UIV PMMA augmentation, and UIV fracture were evaluated. Patients were divided into 3 groups: Group U, 15 patients with unicortical screw fixation at the UIV; Group P, 16 with bicortical screw fixation and PMMA augmentation at the UIV; and Group B, 21 with bicortical screw fixation without PMMA augmentation at the UIV.RESULTSThe mean number of levels fused was 6.5 ± 2.5, 7.5 ± 2.5, and 6.5 ± 2.5; the median age was 50 ± 29, 72 ± 6, and 59 ± 24 years; and the mean follow-up was 31.5 ± 23.5, 13 ± 6, and 24 ± 17.5 months in Groups U, P, and B, respectively (p > 0.05). There were no significant differences in balance-related parameters (LL, sagittal vertical axis, pelvic incidence–LL, and so on) among the groups. UIV fracture rates in Groups U (0%), P (31.3%), and B (42.9%) increased in sequence by group (p = 0.006). UIV bicortical screw fixation increased the risk for UIV fracture (OR 5.39; p = 0.02).CONCLUSIONSBicortical screw fixation at the UIV is a major risk factor for early UIV compression fracture, regardless of whether a thoracolumbosacral orthosis is used. To reduce the proximal junctional failure, unicortical screw fixation at the UIV is essential in adult spinal deformity correction surgery.


2021 ◽  
pp. 1-10
Author(s):  
Scott L. Zuckerman ◽  
Christopher S. Lai ◽  
Yong Shen ◽  
Nathan J. Lee ◽  
Mena G. Kerolus ◽  
...  

OBJECTIVE The authors’ objectives were: 1) to evaluate the incidence and risk factors of iatrogenic coronal malalignment (CM), and 2) to assess the outcomes of patients with all three types of postoperative CM (iatrogenic vs unchanged/worsened vs improved but persistent). METHODS A single-institution, retrospective cohort study was performed on adult spinal deformity (ASD) patients who underwent > 6-level fusion from 2015 to 2019. Iatrogenic CM was defined as immediate postoperative C7 coronal vertical axis (CVA) ≥ 3 cm in patients with preoperative CVA < 3 cm. Additional subcategories of postoperative CM were unchanged/worsened CM, which was defined as immediate postoperative CVA within 0.5 cm of or worse than preoperative CVA, and improved but persistent CM, which was defined as immediate postoperative CVA that was at least 0.5 cm better than preoperative CVA but still ≥ 3 cm; both groups included only patients with preoperative CM. Immediate postoperative radiographs were obtained when the patient was discharged from the hospital after surgery. Demographic, radiographic, and operative variables were collected. Outcomes included major complications, readmissions, reoperations, and patient-reported outcomes (PROs). The t-test, Kruskal-Wallis test, and univariate logistic regression were performed for statistical analysis. RESULTS In this study, 243 patients were included, and the mean ± SD age was 49.3 ± 18.3 years and the mean number of instrumented levels was 13.5 ± 3.9. The mean preoperative CVA was 2.9 ± 2.7 cm. Of 153/243 patients without preoperative CM (CVA < 3 cm), 13/153 (8.5%) had postoperative iatrogenic CM. In total, 43/243 patients (17.7%) had postoperative CM: iatrogenic CM (13/43 [30.2%]), unchanged/worsened CM (19/43 [44.2%]), and improved but persistent CM (11/43 [25.6%]). Significant risk factors associated with iatrogenic CM were anxiety/depression (OR 3.54, p = 0.04), greater preoperative sagittal vertical axis (SVA) (OR 1.13, p = 0.007), greater preoperative pelvic obliquity (OR 1.41, p = 0.019), lumbosacral fractional (LSF) curve concavity to the same side of the CVA (OR 11.67, p = 0.020), maximum Cobb concavity opposite the CVA (OR 3.85, p = 0.048), and three-column osteotomy (OR 4.34, p = 0.028). In total, 12/13 (92%) iatrogenic CM patients had an LSF curve concavity to the same side as the CVA. Among iatrogenic CM patients, mean pelvic obliquity was 3.1°, 4 (31%) patients had pelvic obliquity > 3°, mean preoperative absolute SVA was 8.0 cm, and 7 (54%) patients had preoperative sagittal malalignment. Patients with iatrogenic CM were more likely to sustain a major complication during the 2-year postoperative period than patients without iatrogenic CM (12% vs 33%, p = 0.046), yet readmission, reoperation, and PROs were similar. CONCLUSIONS Postoperative iatrogenic CM occurred in 9% of ASD patients with preoperative normal coronal alignment (CVA < 3 cm). ASD patients who were most at risk for iatrogenic CM included those with preoperative sagittal malalignment, increased pelvic obliquity, LSF curve concavity to the same side as the CVA, and maximum Cobb angle concavity opposite the CVA, as well as those who underwent a three-column osteotomy. Despite sustaining more major complications, iatrogenic CM patients did not have increased risk of readmission, reoperation, or worse PROs.


Physiotherapy ◽  
2015 ◽  
Vol 23 (4) ◽  
Author(s):  
Kamila Jasińska

AbstractA stroke has a number of direct effects on body balance. Despite the progress in medical science, it continues to be one of the major causes of disability in adults.The objective of the study was to evaluate the body balance in people after stroke depending on the side of hemiparesis.The study included 30 patients with left and right-sided hemiparesis. The mean age of the patients was 66 years. The tests were conducted on the R50300 Cosmogamma balance platform, in a standing position. Each patient was examined twice: with and without vision, in a standing position. The statistical analysis was carried out using the STATISTICA software.The results revealed statistical differences in the maximum lateral sways of the Centre of Pressure (COP) with the eyes open, the maximum front-back sways of the Centre of Pressure with the eyes closed, and the mean COP values in the frontal plane with and without vision in individuals with right and left-sided hemiparesis. Patients with left and right-sided hemiparesis were found to underload the affected side, regardless of whether they were tested with or without vision. Moreover, patients with right-sided hemiparesis who were tested with their eyes open had greater difficulty maintaining body balance in the frontal plane than those with left-sided hemiparesis, and patients with right-sided hemiparesis who were examined with their eyes closed had greater difficulty maintaining body balance in the sagittal plane than those with left-sided hemiparesis.During the posturographic examination, individuals with left and right-sided hemiparesis displayed underloading of the affected side, both when tested with their eyes open and closed. When tested with vision, patients with right-sided hemiparesis had greater difficulty maintaining body balance in the frontal plane than those with left-sided hemiparesis. When tested without vision, patients with right-sided hemiparesis had greater difficulty maintaining body balance in the sagittal plane than those with left-sided hemiparesis.


2017 ◽  
Vol 27 (6) ◽  
pp. 650-660 ◽  
Author(s):  
Abhijeet Kadam ◽  
Nathan Wigner ◽  
Philip Saville ◽  
Vincent Arlet

OBJECTIVEThe authors’ aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities.METHODSThe authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (< 6 levels). Preoperative and postoperative standing radiographs were evaluated to measure segmental lordosis (SL) along with standard sagittal parameters. Radiographic signs of pseudarthrosis at previously fused levels were also sought in all patients.RESULTSThe average patient age was 54 years (range 30–66 years). The mean follow-up was 11.5 months (range 5–26 months). The mean SL achieved with 12°, 20°, and 30° cages was 13.1°, 19°, and 22.4°, respectively. The increase in postoperative SL at the respective surgically treated levels for 12°, 20°, and 30° cages that were used to overpower posterior instrumentation/fusion averaged 6.1° (p < 0.05), 12.5° (p < 0.05), and 17.7° (p < 0.05), respectively. No statistically significant difference was found in SL correction at levels in patients who had pseudarthrosis (n = 18) versus those who did not (n = 18). The mean overall lumbar lordosis increased from 44.3° to 59.8° (p < 0.05). In the long-construct group, the mean improvement in sagittal vertical axis was 85.5 mm (range 19–249.3 mm, p < 0.05). Endplate impaction/collapse was noted in 3 of 36 levels (8.3%). The anterior complication rate was 13.3%. No neurological complications or vascular injuries were observed.CONCLUSIONSALIF in which hyperlordotic cages are used to overpower posterior spinal instrumentation and fusion can be expected to produce an increase in SL of a magnitude that is roughly half of the in-built cage lordotic angle. This technique may be particularly suited for lordosis correction from the front at lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.


2018 ◽  
Vol 29 (4) ◽  
pp. 414-421 ◽  
Author(s):  
M. Burhan Janjua ◽  
Jared C. Tishelman ◽  
Dennis Vasquez-Montes ◽  
Max Vaynrub ◽  
Thomas J. Errico ◽  
...  

OBJECTIVEPreoperative planning of thoracolumbar deformity (TLD) surgery has been shown to improve radiographic and clinical outcomes. One of the confounders in attaining optimal postoperative alignment is the reciprocal hyperkyphosis of unfused thoracic segments. Traditional planning utilizes standing radiographs, but the value of sitting radiographs to predict thoracic flexibility has not been investigated. Authors of the present study propose that alignment changes from a sitting to a standing position will predict changes in unfused thoracic segments after TLD correction.METHODSPatients with degenerative spine pathology underwent preoperative sitting and standing full-spine stereotactic radiography. A subset of TLD patients who had undergone corrections with minimum T10-pelvis fusions was analyzed in terms of pre- to postoperative alignment. Radiographic parameters were analyzed, including the T1 pelvic angle (TPA), T1–L1 pelvic angle (TLPA), lumbar pelvic angle (LPA), pelvic tilt (PT), mismatch between pelvic incidence and lumbar lordosis (PI-LL mismatch), and T2–12 kyphosis (TK). Thoracic compensation was calculated as the expected TK minus actual TK (i.e., [2/3 × PI] − actual TK). Statistical analysis consisted of paired and unpaired t-tests and linear regression analysis.RESULTSThe authors retrospectively identified 137 patients with full-body standing and sitting radiographs. The mean age of the patients was 60.9 years old, 60.0% were female, and the mean BMI was 27.8 kg/m2. The patients demonstrated significantly different radiographic alignments in baseline spinopelvic and global parameters from the preoperative sitting versus the standing positions: LL (−34.20° vs −47.87°, p < 0.001), PT (28.31° vs 17.50°, p < 0.001), TPA (27.85° vs 16.89°, p < 0.001), TLPA (10.63° vs 5.17°, p < 0.001), and LPA (15.86° vs 9.67°, p < 0.001). Twenty patients (65.0% female) with a mean age of 65.3 years and mean BMI of 30.2 kg/m2 had TLD and underwent surgical correction (pre- to postoperative standing change in TPA: 33.90° to 24.50°, p = 0.001). Preoperative sitting radiographs demonstrated significant differences in alignment compared to postoperative standing radiographs: larger TPA (39.10° vs 24.50°, p < 0.001), PT (35.40° vs 28.10°, p < 0.001), LL (−11.20° vs −44.80°, p < 0.001), LPA (22.80° vs 14.20°, p < 0.001), and unfused Cobb (T2 to upper instrumented vertebra [UIV] Cobb angle: 19.95° vs 27.50°, p = 0.039). Also in the TLD group, mean thoracic compensation was 6.75°. In the linear regression analysis, the change from sitting to standing predicted pre- to postoperative changes for TK and the unfused thoracic component of TPA (5° change in preoperative sitting to preoperative standing corresponded to a pre- to postoperative change in standing TK of 6.35° and in standing TPA of 7.23°, R2 = 0.30 and 0.38, respectively).CONCLUSIONSSitting radiographs were useful in demonstrating spine flexibility. Among the TLD surgery group, relaxation of the unfused thoracic spine in the sitting position predicted the postoperative increase in kyphosis of the unfused thoracic segments. Sitting radiographs are a useful tool to anticipate reciprocal changes in thoracic alignment that diminish global corrections.


2016 ◽  
Vol 25 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Khoi D. Than ◽  
Paul Park ◽  
Kai-Ming Fu ◽  
Stacie Nguyen ◽  
Michael Y. Wang ◽  
...  

OBJECTIVE Minimally invasive surgery (MIS) techniques are increasingly used to treat adult spinal deformity. However, standard minimally invasive spinal deformity techniques have a more limited ability to restore sagittal balance and match the pelvic incidence–lumbar lordosis (PI-LL) than traditional open surgery. This study sought to compare “best” versus “worst” outcomes of MIS to identify variables that may predispose patients to postoperative success. METHODS A retrospective review of minimally invasive spinal deformity surgery cases was performed to identify parameters in the 20% of patients who had the greatest improvement in Oswestry Disability Index (ODI) scores versus those in the 20% of patients who had the least improvement in ODI scores at 2 years' follow-up. RESULTS One hundred four patients met the inclusion criteria, and the top 20% of patients in terms of ODI improvement at 2 years (best group, 22 patients) were compared with the bottom 20% (worst group, 21 patients). There were no statistically significant differences in age, body mass index, pre- and postoperative Cobb angles, pelvic tilt, pelvic incidence, levels fused, operating room time, and blood loss between the best and worst groups. However, the mean preoperative ODI score was significantly higher (worse disability) at baseline in the group that had the greatest improvement in ODI score (58.2 vs 39.7, p < 0.001). There was no difference in preoperative PI-LL mismatch (12.8° best vs 19.5° worst, p = 0.298). The best group had significantly less postoperative sagittal vertical axis (SVA; 3.4 vs 6.9 cm, p = 0.043) and postoperative PI-LL mismatch (10.4° vs 19.4°, p = 0.027) than the worst group. The best group also had better postoperative visual analog scale back and leg pain scores (p = 0.001 and p = 0.046, respectively). CONCLUSIONS The authors recommend that spinal deformity surgeons using MIS techniques focus on correcting a patient's PI-LL mismatch to within 10° and restoring SVA to < 5 cm. Restoration of these parameters seems to impact which patients will attain the greatest degree of improvement in ODI outcomes, while the spines of patients who do the worst are not appropriately corrected and may be fused into a fixed sagittal plane deformity.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xuhong Xue ◽  
Sheng Zhao ◽  
Feng Miao ◽  
Kai Li ◽  
Bin Zhao

Abstract Background Two ipsilateral hemivertebrae is less common and presents severe growth imbalance caused by the vertebral anomalies. However, there is a paucity of reports regarding to two ipsilateral thoracolumbar hemivertebrae. The purpose of present study is to evaluate the long-term outcomes of the posterior surgical correction of thoraco-lumbar spine deformity caused by two ipsilateral hemivertebrae. Methods From 2006 to 2014, a total of 14 consecutive pediatric patients with congenital thoraco-lumbar hemivertebrae were treated by posterior excision of hemivertebrae with short segment fusion. The following parameters were measured: coronal major curvature, cranial and caudal compensatory curvature, segmental kyphosis, lumbar lordosis, trunk shift, apical vertebra translation and sagittal vertical axis. These results were compared and evaluated in preoperatively, immediately postoperatively and at the final follow-up. All patients had a minimum of 5 years follow-up. Results The mean age at surgery was 11.1 ± 4.8 years (2yos to 17yos). The mean follow-up period was 80.2 ± 19.4 months (60mons to 117mons). There was a mean improvement of 74.2% in the coronal major curve from a mean angle of 64.1° before surgery to 15.8° at the final follow-up. The cranial and caudal curves improved of 69.8 and 69.0% from 25.6° to 7.7°, 26.9 to 8.2, respectively. The mean thoraco-lumbar kyphosis was 59.9° before and 13.6° after surgery, 20.8° at the final follow-up. Alignment in the coronal and sagittal plane was either maintained or improved within normal values in all patients. Conclusions Good correction and spinal balance can be achieved by posterior-only hemivertebrectomy in patients with thoracolumbar kyphocsoliosis caused by two ipsilateral hemivertebra. The complication of neurological injury is low but a technically demanding procedure. More attention should be paid in residual curve progression after surgery.


2020 ◽  
Vol 99 (8) ◽  

Introduction: The study compares the results of open reduction using volar locking plates with ligamentotaxis by external fixation in fractures of distal radius type 2R3C according to AO classification. Methods: A retrospective study evaluating the results of osteosynthesis in patients with distal radius fractures type 2R3C according to AO classification, operated until December 2018. The ORIF method with volar locking plates (LCP) was used in 54 patients, and closed reduction with ligamentotaxis using external fixation (EF) was used in 33 patients. The mean age of the patients was 46.7 years in the LCP group and 59.6 years in the EF group. All were evaluated for their X-ray and functional outcomes and according to the Green and O’Brien score at 6 and 12 months after surgery. Results: According to X-rays at 12 months in the LCP group, the mean sagittal tilt was 10.13°, the mean radial inclination was 23.89°, and the mean radial length was 11.84 mm. In the EF group, the mean sagittal tilt was 6.32°, the mean radial inclination was 24.78°, and the mean radial length was 9.89 mm. According to the Green and O’Brien score, we recorded a mean score of 84.44 points in the LCP group at 12 month; we achieved good and excellent results in 83.33% of the patients and no poor result was observed. In the EF group the final mean score was 77.27; good and excellent results were achieved in 45.46% of the patients and a poor result in one patient. Conclusion: Based on the results in our group of patients, the internal type osteosynthesis using LCP implants can be recommended as a first-choice technique in the treatment of 2R3C fractures according to AO classification.


Author(s):  
Paulina Hebisz ◽  
Rafal Hebisz ◽  
Marek Zaton

AbstractBackground: The purpose of this study was to compare body balance in road and off-road cyclists, immediately before and after the racing season.Material/Methods: Twenty individuals participated in the study and they were divided into two groups: specialists in road-cycling (n = 10) and in off-road cycling (n = 10). Immediately before and after the five-month racing season stabilographic trials were carried out (at rest and after progressive exercise). In assessing body balance the distance and velocity of the centre shifts (in the anterior-posterior and left-right direction) were analysed. The tests were performed with the cyclists’ eyes open, eyes closed, and in feedback.Results: After the racing season, in the off-road cyclists’ group, distance and velocity of the centre of pressure shifts increased after a progressive exercise.Conclusions: In the off-road cyclists’ group the balance of the body in the sagittal plane deteriorated after the racing season. Moreover, after the racing season off-road cyclists were characterized by a worse balance of the body, compared to road cyclists


Sign in / Sign up

Export Citation Format

Share Document