Analysis of sagittal spinopelvic parameters in achondroplasia

Advances in the mechanism and therapies of achondroplasia

Achondroplasia (ACH), is the prevailing type of genetic dwarfism in humans, caused by mutations in fibroblast growth factor receptor 3 (FGFR3) that are inherited in an autosomal dominant manner. FGFR3 is mainly expressed in condensed mesenchyme, chondrocytes, and mature osteoblasts and osteoclasts, in which it regulates the formation, development, growth, and remodeling of the skeletal system. Mutations in FGFR3 causing ACH result in enhanced FGFR3 signaling through combined mechanisms including enhancing FGF dimerization and tyrosine kinase activity and stabilizing FGF receptors. In ACH, suppression of the proliferation and maturation of chondrocytes in the growth plate leads to a notable reduction in growth plate size, trabecular bone volume, and bone elongation through a profound enhancement of FGFR3 signaling. This review aims to comprehensively outline the cellular and molecular mechanisms contributing to the pathological process of ACH and its potential therapeutic interventions.

Bipedal static postural stability in children with achondroplasia compared to typically developed children in the age range of 9-12 years - A pilot study

BACKGROUND

Postural stability is a key factor in maintaining an upright standing position. Children with average height (CAH) have elaborate general postural stability up to the age of seven years. Children with achondroplasia (ACH) face body disproportions like shorter arms and legs, bowing of the legs as well as hyperlordosis and hypokyphosis in the spine. These misalignments might affect the postural stability of children with achondroplasia. Therefore, this study aims to investigate if there are differences between children with ACH and CAH in four different bipedal static balance tasks.

METHODS

23 children (11 ACH & 12 CAH) participated in this study. Every subject performed four static balance tasks: bipedal standing on the ground (eyes open/closed) and bipedal standing on a foam pad (eyes open/closed). All trials were recorded on a force plate (AMTI) with 1000 Hz and a duration of 30 seconds for each condition. Parameters of interest are the length of CoP (mm), surface area 95 (mm2) as well as three defined ranges of frequency (low: 0.02 - 0.1 Hz, medium: 0.1 - 1 Hz, and high: 1 - 10 Hz) for anterior-posterior (AP) and mediolateral direction (ML). A Mann-Whitney U test was used to investigate the parameters length of CoP (AP & ML) and surface area 95 %. One-way ANOVA was used for the area under the curve parameter for each frequency range.

RESULTS

Nonsignificant differences were found for all parameters. However, non-significant medium and strong effect sizes were detected for certain parameters of the frequency analysis.

SIGNIFICANCE

Understanding strategies to maintain postural stability for ACH and CAH during a bipedal stance at a deeper level using frequency analysis helps to detect in which way disturbances might occur and how both cohorts react to those. Knowing the challenges of maintaining postural stability can help to develop therapeutic interventions to reduce disturbances.

Association Between Radiological Severity of Lumbar Spinal Stenosis and Spinopelvic Parameters in Adult Patients With Achondroplasia

BACKGROUND AND OBJECTIVES

Adults with achondroplasia are more vulnerable to suffer from neurogenic claudication because of a congenital narrow spinal canal, which makes them susceptible to lumbar spinal stenosis (LSS). The study aims to investigate the correlations between sagittal alignment parameters and the degree of LSS in patients with achondroplasia with LSS.

METHODS

The radiological data of adult achondroplasts presented to the neurosurgical clinic of our medical center from 2019 to 2022 were collected. Lumbar stenosis was graded using the Schizas scale, and the dural sac cross-sectional area (DSCA) was measured. The angles defining the spinopelvic parameters comprising lumbar lordosis, thoracolumbar kyphosis, sagittal vertical axis, pelvic tilt, sacral slope, and pelvic incidence were measured. Spearman or Pearson correlation was used to investigate the association between sagittal misalignment and LSS.

RESULTS

A total of 34 achondroplastics were enrolled, with a median age of 44.3 ± 15.5 years, ranging from 18.6 to 78.5 years. Larger thoracolumbar kyphosis was associated with more severe stenosis according to the Schizas scale of the L 12 lumbar level (r = 0.44, P = .020, 95% CI [0.08, 0.70]). Larger sagittal vertical axis correlated with a smaller DSCA at L 23 (r = -0.53, P = .036, 95% CI [-0.81, -0.04]) and L 45 (r = -0.66, P = .004, 95% CI [-0.87, -0.26]). Larger pelvic tilt was demonstrated to be associated with a smaller DSCA of the L 34 lumbar level (r = -0.42, P = .027, 95% CI [-0.68, -0.05]) and the L 45 lumbar level (r = -0.47, P = .011, 95% CI [-0.71, -0.12]).

CONCLUSION

The upper LSS may be attributed to an increased kyphosis of the thoracolumbar spine. On the contrary, the lower LSS seemed to be correlated with a more backward tilt of the pelvis.

Surgery for Spinal Stenosis in Achondroplasia: Causes of Reoperation and Reduction of Risks

BACKGROUND

Individuals with achondroplasia are prone to symptomatic spinal stenosis requiring surgery. Revision rates are thought to be high; however, the precise causes and rates of reoperation are unknown. The primary aim of this study is to investigate the causes of reoperation after initial surgical intervention in individuals with achondroplasia and spinal stenosis. In addition, we report on surgical techniques aimed at reducing the risks of these reoperations.

METHODS

A retrospective review was conducted over an 8-year period of all patients with achondroplasia at a single institution that serves as a large referral center for patients with skeletal dysplasias. Patients with achondroplasia who underwent spinal surgery for stenosis were identified and the need for revision surgery was studied. Data collected included demographic, surgical, and revision details. Fisher exact test was used to determine if an association existed between construct type and the need for revisions.

RESULTS

Thirty-three of the 130 (22%) patients with achondroplasia required spinal stenosis surgery. Twenty-four individuals who met the criteria were selected for analysis. The initial spine surgery was at an average age of 18.7 years (SD: 10.1 y). Nine patients (38%) required revision surgeries, and 3 required multiple revisions. Five of 9 (56%) of the revisions had primary surgery at an outside institution. Revision surgeries were due to caudal pseudarthrosis (the distal instrumented segment) (8), proximal junctional kyphosis (PJK) (7), and new neurological symptoms (7). There was a significant association found between construct type and the need for revision ( P =0.0111). The pairwise comparison found that short fusions were significantly associated with the need for revision compared with the interbody group ( P =0.0180). PJK was associated with short fusions when compared with the long fusion group ( P =0.0294) and the interbody group ( P =0.0300). Caudal pseudarthrosis was associated with short fusions when compared with the interbody group ( P =0.0015). Multivariate logistic regression found long fusion with an interbody was predictive of and protective against the need for revision surgery ( P =0.0246). To date, none of the initial cases that had long fusions with caudal interbody required a revision for distal pseudarthrosis.

CONCLUSIONS

In patients with achondroplasia, the rate of surgery for spinal stenosis is 22% and the risk of revision is 38% and is primarily due to pseudarthrosis, PJK, and recurrent neurological symptoms. Surgeons should consider discussing spinal surgery as part of the patient's life plan and should consider wide decompression of the stenotic levels and long fusion with the use of an interbody cage at the caudal level in all patients to reduce risks of revision.

LEVEL OF EVIDENCE

Level IV-Retrospective case series.

How pain affect real life of children and adults with achondroplasia: A systematic review

The clinical features of achondroplasia can cause acute self-limited pain that can evolve into chronic pain. Pain causes a low quality of life, in terms of physical, emotional, social, and school functioning in both adult and children with achondroplasia. We conducted a systematic review according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement to describe prevalence, assessment tools, causes and management strategies of pain in this rare disease. We found that shoulder and knee pain is typically referred during infancy, while knee pain is generally referred around 5-6 years of age. The prevalence of general pain in adolescence can be as high as 90%. Chronic pain in the achondroplasia population increases with age, with up to 70% of adults reporting general pain and back pain. Recognizing the multiple determinants of acute and chronic pain in patients with achondroplasia may enable physicians to better understand and manage this burden, particularly with the advent of new drugs that may modify some of the striking features of achondroplasia.

The effect of ethnicity on the age-related changes of spinopelvic characteristics: a systematic review

Spinopelvic characteristics influence the hip's biomechanical behaviour. However, to date there is little knowledge defining what 'normal' spinopelvic characteristics are. This study aims to determine how static spinopelvic characteristics change with age and ethnicity among asymptomatic, healthy individuals. This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify English studies, including ≥ 18-year-old participants, without evidence of hip or spine pathology or a history of previous surgery or interventional treatment, documenting lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). From a total of 2,543 articles retrieved after the initial database search, 61 articles were eventually selected for data extraction. When all ethnicities were combined the mean values for LL, SS, PT, and PI were: 47.4° (SD 11.0°), 35.8° (SD 7.8°), 14.0° (SD 7.2°), and 48.8° (SD 10°), respectively. LL, SS, and PT had statistically significant (p < 0.001) changes per decade at: -1.5° (SD 0.3°), -1.3° (SD 0.3°), and 1.4° (SD 0.1°). Asian populations had the largest age-dependent change in LL, SS, and PT compared to any other ethnicity per decade at: -1.3° (SD 0.3°) to -0.5° (SD 1.3°), -1.2° (SD 0.2°) to -0.3° (SD 0.3°), and 1.7° (SD 0.2°) versus 1.1° (SD 0.1°), respectively. Ageing alters the orientation between the spine and pelvis, causing LL, SS, and PT to modify their orientations in a compensatory mechanism to maintain sagittal alignment for balance when standing. Asian populations have the largest degree of age-dependent change to their spinopelvic parameters compared to any other ethnicity, likely due to their lower PI.

Meeting Report from 2nd ICCBH-ERN BOND Spinal Complications in Children and Adults with Achondroplasia Workshop, Dublin, Ireland, 2nd July 2022

A pre-meeting workshop on spinal complications in children and adults with achondroplasia was held in Dublin, Ireland at the 10th International Conference on Children's Bone Health (ICCBH) 2-5 July 2022. The pathophysiology, natural history and medical/surgical management of thoraco-lumbar kyphosis and spinal stenosis remains poorly described in the literature. The structure of the workshop consisted of lectures, a debate and an interactive round table discussion. In total over 100 delegates affiliated to over 70 institutions from 20 countries were in attendance.

Improvement of the sagittal alignment of the spine in patients with achondroplasia after subtrochanteric femoral lengthening

PURPOSE

Limb-lengthening surgery to treat short stature has undergone great development in recent years with the use of intramedullary telescopic nails (TIMNs). A limited number of studies have explored the impact of lower limb lengthening on the spine, though their conclusions are not consistent. The aim of this research is to analyze changes in spinopelvic sagittal alignment and balance after lower limb lengthening in achondroplastic patients.

METHODS

Prospective study of patients with achondroplasia treated with bilateral femoral lengthening using an TIMN. Different sagittal spinal and pelvic plane parameters were measured on pre- and 2 year postoperative lateral spine radiographs: cervical lordosis, thoracic kyphosis, TL junction, lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope (SS), and sagittal vertebral axis (SVA). Similarly, information regarding the elongation procedure was recorded.

RESULTS

A total of 10 patients were included (60% male), with a median age of 13.39 (2.32) years at first surgery and a median height of 120.3 (5.75) cm. A 10 cm elongation was performed in all patients through femoral subtrochanteric osteotomy. Statistically significant changes were found in LL -15.2 (7.4-17.9)º (p = 0.028), PT 11.7 (10.3-13.4)º (p = 0.018), SS - 11.6 (- 13.4 to - 10.4)º (p = 0.018) and |SVA| - 34.3 (- 39.10 to - 1.7) mm (p = 0.043).

CONCLUSION

Bilateral lower limb lengthening in patients with achondroplasia not only increases their size, but also improves sagittal spinopelvic alignment and balance. This may be due to retroversion of the pelvis and subsequent decrease in SS and LL as a result of the increased tightness of the gluteus maximus and hamstring muscles after femoral lengthening through subtrochanteric osteotomy.

LEVEL OF EVIDENCE

II, prospective comparative cohort study, before and after intervention.

Neurosurgical Evaluation and Management of Adults with Achondroplasia

Much of the current medical discussion for within centers for skeletal dysplasia and specifically patients with achondroplasia focuses on infancy and early childhood. Most neurosurgical concerns arise due to a defect in the endochondral ossification, resulting on early fusion of the synchondrosis. As patients age, the neurosurgical focus shifts from primarily cranial to spinal concerns. Often pediatric neurosurgeons may continue to follow their patients with skeletal dysplasia. However, general adult neurosurgeons and orthopedic surgeons may see these graduated adults in their practice. This article provides a review of the common neurosurgical concerns for patients with achondroplasia.

Global Sagittal Balance of Spine in Asymptomatic Controls: A Systematic Review and Meta-Analysis

OBJECTIVE

To assess the global sagittal balance of spine (GSBS) in asymptomatic controls.

METHODS

PubMed, Scopus, Cochrane library, and Web of Science searched up to July 2020. Studies were screened for the GSB parameters including T1 pelvic angle (TPA), spinosacral angle (SSA), sagittal vertical axis (SVA), C7/sacrofemoral distance ratio (Barrey index), odontoid hip axis (OD-HA), and Full Balance Index (FBI) as measured in asymptomatic participants. A meta-analysis was performed to synthesize pooled estimates. Heterogeneity and publication bias were assessed.

RESULTS

Overall, 76 studies were identified including 12,169 participants (54.7% female) with mean age ranges from 12.0 to 72.9 years old. We used the Newcastle-Ottawa Scale (NOS) to evaluate the quality of studies included in this review. Begg's test did not indicate obvious publication bias. The pooled analysis reveals that the mean (standard deviation) normative values were: 1) age ˃18 years, SSA (°), 127.6 (0.89); SVA absolute value (millimeters), 13.1 (1.13); TPA (°), 9.8 (1.13); T1SPI (°), -4.3 (0.57); and Barrey index absolute value, 0.51 (0.3). The mean value of the OD-HA (°) was reported 2.9 (1.6), and the FBI average value was less than 5°. 2) Age ≤18 years, SSA (°), 132.1 (8.3); SVA absolute value (millimeters), 11.9 (2.0); and Barrey index, -0.7 (8.3). A significant difference was observed between the 2 age groups based on SVA and SSA.

CONCLUSIONS

This paper presents normative data on TPA, SSA, SVA, Barrey index, OD-HA, and FBI as a reference for evaluating/measuring a GSB of spine in asymptomatic controls.

Lumbar spinal stenosis and disc alterations affect the upper lumbar spine in adults with achondroplasia

In achondroplasia, lumbar spinal stenosis arises from congenital dysplasia and acquired degenerative changes. We here aimed to describe the changes of the lumbar spinal canal and intervertebral disc in adults. We included 18 adults (age ≥ 18 years) with achondroplasia and lumbar spinal stenosis. Radiographs were used to analyze spinal-pelvic angles. Antero-posterior diameter of the spinal canal and the grade of disc degeneration were measured by MRI. Antero-posterior diameters of the spinal canal differed by spinal level (P < 0.05), with lower values observed at T12-L1, L1-2 and L2-3. Degrees of disc degeneration differed by intervertebral level, with higher degrees observed at L1-2, L2-3 and L3-4. A significant correlation was found between disc degeneration and thoraco-lumbar kyphosis at L2-3, between antero-posterior diameter of the spinal canal and lumbar lordosis at T12-L1 and L2-3, and between antero-posterior diameter of the spinal canal and thoraco-lumbar kyphosis at L1-2. Unlike the general population, spinal stenosis and disc degeneration involve the upper part of the lumbar spine in adults with achondroplasia, associated with thoraco-lumbar kyphosis and loss of lumbar lordosis.

Sagittal Spinopelvic Parameters in Children With Achondroplasia

STUDY DESIGN

Retrospective cross-sectional, longitudinal radiographic analysis.

OBJECTIVE

To report the natural history of spinopelvic parameters in achondroplasia.

SUMMARY OF BACKGROUND DATA

Sagittal spinal deformity is common in children with achondroplasia. However, few data exist on their normative spinal parameters.

METHODS

Lateral standing spine radiographs of children with achondroplasia were reviewed. Measurements included thoracic kyphosis, lumbar lordosis (LL), thoracolumbar kyphosis (TLK), pelvic incidence (PI), T1 pelvic angle (TPA), and sagittal balance (SVA). Comparison between age groups and longitudinal analysis of children with minimum five-year radiographic evaluation was performed; evolution of radiographic measurements was assessed. Children who underwent surgical correction of TLK were studied separately to describe changes of sagittal spinal parameters associated with TLK surgical correction.

RESULTS

In cross-sectional analysis, 745 radiographs (282 children) were measured. During the first three years, TLK decreased and LL and sacral slope increased significantly. After age 3 years, TLK decreased gradually until age 10. Afterwards, TLK decrease became non-significant. PI increased gradually after age 10. In the longitudinal group, 81 children were followed an average of 8.7 (5-19) years between age 4.4 and 13.1 years. TLK decreased; LL and PI increased significantly. TPA and SVA remained within the normal range although changes with growth were statistically significant. In the surgical group, 19 children underwent surgical TLK correction. Apart from TLK correction, no sagittal parameters changed significantly after surgery. These 19 children had higher TLK and lower LL compared with a nonsurgical group at similar average age.

CONCLUSION

In children with achondroplasia, TLK improvement occurs primarily before age 3 years; hyperlordosis at the lumbosacral level is the compensatory mechanism. Significant changes in the sagittal spinal parameters occur early in life, suggesting the importance of attention to sagittal malalignment to prevent any possible clinical sequelae of severe hyperlordosis.

LEVEL OF EVIDENCE

Level III, prognostic study.

Sustained hip flexion contracture after femoral lengthening in patients with achondroplasia

Background

Hip flexion contracture often occurs after femoral lengthening in patients with achondroplasia, but few studies have investigated its development in these patients. The purpose of this study was to analyze sustained hip flexion contracture in achondroplasia patients who underwent femoral lengthening and to identify contributing factors.

Methods

This study included 34 patients with achondroplasia who underwent femoral lengthening (mean age at operation, 11.1 years). Sustained hip flexion was defined as flexion contracture lasting > 6 months postoperatively despite physiotherapy. Demographic data, spinopelvic parameters (pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, and sagittal vertical axis), and quantitative assessments of femoral lengthening were investigated. The associations among these factors and the development of sustained hip flexion contracture were assessed.

Results

Sustained hip flexion contracture developed in 13 (38%) of 34 achondroplasia patients after femoral lengthening. Eight (62%) of these 13 patients concomitantly exhibited limitation of knee flexion. Excessive femoral lengthening (odds ratio [OR], 1.450; 95% confidence interval [CI], 1.064 to 1.975; p = 0.019) and forward sagittal vertical axis tilt (OR, 1.062; 95% CI, 1.001 to 1.127; p = 0.047) contributed to sustained hip flexion contracture.

Conclusions

Sustained hip flexion contracture frequently occurs after femoral lengthening in achondroplasia patients. Both excessive femoral lengthening and preoperative forward SVA tilt may contribute to the development of sustained hip flexion contracture in these patients.

The Efficacy of Brace Treatment for Thoracolumbar Kyphosis in Patients With Achondroplasia

STUDY DESIGN

A retrospective study.

OBJECTIVES

The aim of this study was to evaluate the outcome of brace treatment in the correction of thoracolumbar kyphosis (TLK) for patients with achondroplasia and to determine the factors associated with bracing efficacy.

SUMMARY OF BACKGROUND DATA

Brace treatment has been used to correct TLK in patients with achondroplasia. However, there was a paucity of knowledge concerning its effectiveness.

METHODS

A total of 33 achondroplasic patients treated by bracing were included in this study. Radiographic parameters including TLK, lumbar lordosis, curve magnitude, apical vertebral translation (AVT), percentage of apical vertebral wedging, pelvic tilt (PT), and pelvic incidence were recorded for each patient at the visit. Comparison of these parameters between the initial visit and the final visit was performed using the Student t test. Factors associated with the correction of TLK were evaluated using the logistic regression analysis.

RESULTS

The mean age at presentation was 27.5 ± 13.4 months. The mean period of treatment was 32.2 ± 15.7 months, and the mean period of follow-up was 25.7 ± 11.3 months. At the initial visit, the mean value of TLK and the percentage of apical vertebral wedging were 41.7 ± 15.4° and 61.4% ± 16.2%, respectively. At the final visit, the TLK and apical vertebral wedging were remarkably reduced to 29.5 ± 20.8° and 52.1% ± 18.7%, respectively. The logistic regression analysis showed that initial TLK, AVT, percentage of apical vertebral wedging, and PT were independent factors associated with the correction of TLK.

CONCLUSION

Brace treatment can effectively correct TLK and restore the morphology of apical vertebral body for patients with achondroplasia. Large TLK, severe apical vertebral wedging, presence of AVT, and low PT may be indicative of an unfavorable outcome, which should be taken into account at the initiation of bracing.

LEVEL OF EVIDENCE

4.

Effect of Coronal Scoliotic Curvature on Sagittal Spinal Shape: Analysis of Parameters in Mature Adolescent Scoliosis Patients

STUDY DESIGN

A radiographic analysis with scoliosis patients.

OBJECTIVES

To analyze correlations between sagittal spinal alignment and coronal scoliotic curvature.

SUMMARY OF BACKGROUND DATA

Sagittal spinal alignment and scoliosis may have a significant relationship, and schematic analysis is needed.

METHODS

The study group was comprised of 163 patients with adolescent idiopathic scoliosis. Subjects underwent anteroposterior and lateral radiographs of the whole spine including hip joints. The radiographic parameters used were magnitude, location and direction of curve, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, sacral slope, and pelvic angle. Subjects were classified into 4 groups according to the severity of coronal curvature: Cobb angle ≤20 degrees, Cobb angle 21-40 degrees, Cobb angle 41-60 degrees, and Cobb angle >60 degrees. In addition, subjects were divided into 4 subgroups according to Roussouly's classification (types 1-4) of sagittal spinal shape. Schematic analysis was performed to determine the relationship between coronal and sagittal parameters.

RESULTS

Analysis of parameters with severity of coronal curvature, thoracic kyphosis, and sacral slope were significantly higher in high-grade scoliosis (P<0.05). However, the pelvic angle was higher in low-grade scoliosis, and sagittal balance showed a significantly higher positive value in low-grade scoliosis (P<0.05). In the analysis of sagittal spinal shapes, Roussouly groups 3 and 4 showed more severe scoliosis with higher lumbar lordosis and thoracic kyphosis (P<0.05). In addition, Roussouly group 1 demonstrated a significantly higher incidence of low-grade scoliosis, whereas groups 3 and 4 had a higher incidence of high-degree scoliosis by cross-relation analysis (P<0.05).

CONCLUSIONS

A significant relationship exists between sagittal spinal shape and coronal curvature in scoliosis. Understanding the biplanar shapes of scoliosis may be helpful to the surgeons.

Analysis of hip dysplasia and spinopelvic alignment in cerebral palsy

BACKGROUND CONTEXT

Knowledge of sagittal spinopelvic parameters and hip dysplasia is important in cerebral palsy (CP) patients because these parameters differ from those found in the general population and can be related to symptoms.

PURPOSE

The purpose of this study was to analyze sagittal spinopelvic alignment and determine its relation to hip dysplasia in CP patients.

STUDY DESIGN

Radiological analysis was conducted on patients with CP.

PATIENT SAMPLE

Fifty-four patients with CP and 24 normal controls were included in this study.

OUTCOME MEASURES

Participants underwent radiographs of the whole spine.

METHODS

The patient and control groups comprised 54 CP patients and 24 volunteers, respectively. All underwent lateral radiography of the whole spine and hip joint anteroposterior radiography. The radiographic parameters examined were sacral slope, pelvic tilt, pelvic incidence, S1 overhang, thoracic kyphosis, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, center edge angle, acetabular angle, and migration index. Statistical analysis was performed to identify significant differences and correlations between the two groups.

RESULTS

Sacral slope, thoracolumbar kyphosis, lumbar lordosis, sagittal balance, acetabular angle, and migration index were significantly higher in CP patients, whereas pelvic tilt, S1 overhang, and center edge angle were significantly lower (p<.05). Correlation analysis revealed that pelvic incidence, sacral slope, pelvic tilt, and S1 overhang were related to each other and that thoracolumbar kyphosis was related to the thoracic kyphosis and lumbar lordosis (p<.05). For spinal and pelvic parameters, lumbar lordosis was related to sacral slope, pelvic incidence, pelvic tilt, and S1 overhang; for hip dysplasia parameters, center edge angle and acetabular angle were found to be interrelated (p<.05). Regarding symptoms, pelvic tilt, S1 overhang, and thoracolumbar kyphosis were found to be correlated with symptom severity in patients. However, no hip dysplasia parameters were found to be related to hip or spinal symptoms.

CONCLUSIONS

This study found significant differences between CP patients and normal controls in terms of spinopelvic alignment and hip dysplasia. Furthermore, relationships were found between the sagittal spinopelvic parameters and hip dysplasia, and correlations were found between sagittal spinopelvic parameters and pain.

Evaluation of pelvic morphology in the sagittal plane

BACKGROUND CONTEXT

It is generally accepted that for normal subjects the angle of pelvic incidence (PI) increases during childhood and then remains unchanged throughout adolescence and adulthood. However, recent findings show that PI increases linearly throughout the lifespan due to morphological changes of the pelvis.

PURPOSE

A retrospective study aiming to determine the extent of morphological changes of the pelvis related to the age of the subjects.

STUDY DESIGN

Pelvic morphology was evaluated in a normal adult population by measuring the anatomical parameters of sagittal pelvic alignment.

PATIENT SAMPLE

The final study cohort consisted of 330 subjects (mean age, 45.3 years; standard deviation, 18.1 years; range, 18-87 years; 164 male and 166 female subjects).

OUTCOME MEASURES

Physiologic measures, obtained as measurements of PI, sacral end plate width (S1W), and pelvic thickness (PTH).

METHODS

Parameters of PI, S1W, and PTH were evaluated from computed tomography images of the subjects. The measured PTH was normalized according to S1W and age of the subjects, allowing the comparison among anatomies of different sizes. The normalized components of PTH in anteroposterior and cephalocaudal directions were computed to determine the configuration and extent of changes in pelvic morphology related to subject age.

RESULTS

Statistically significant correlation with both age and PI was obtained for all normalized parameters (except for the anteroposterior component of PTH for male subjects), and no statistically significant differences were observed between the sexes. With increasing PI that occurs due to the aging process, a decrease of PTH can be observed that is manifested not only as an increase of the distance between the sacrum and the hip axis in the anterior direction but considerably more as a decrease of the distance between the sacrum and the hip axis in the cephalic direction. By considering these morphological changes in the pelvis simultaneously, the hip axis can move only within a narrow area.

CONCLUSIONS

The changes in pelvic morphology due to the aging process occur in the anterior direction, which may be due to the remodeling process affecting the coxal bone that results in an anterior drift of the acetabulum relative to the sacrum. More importantly, the changes are considerably more evident in the cephalic direction, which may be the result of the weight-bearing loads and consequent wear of acetabular cartilage.

Analysis of sagittal spinopelvic parameters in cerebral palsy

BACKGROUND CONTEXT

Knowledge of sagittal spinopelvic parameters is important for the treatment of cerebral palsy (CP) because they differ in the normal population and can induce symptoms.

PURPOSE

To analyze the sagittal spinal alignment and the pelvic orientation in CP.

STUDY DESIGN

Radiological analysis of patients with CP.

METHODS

The study and control groups comprised 57 CP patients and 24 healthy volunteers, respectively. All the patients underwent lateral radiography of the whole spine including hip joints. The radiographic parameters examined were sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), S1 overhang (OH), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL1 and 2), and sagittal balance (SB). Statistical analysis was performed to identify the significant differences between the two study groups. In addition, correlations were sought between the parameters and symptoms.

RESULTS

The PT and OH were significantly smaller in the CP patients, whereas SS, TLK, LL1, LL2, and SB were significantly greater (p<.05). Correlation analysis revealed significant relationships between the sagittal parameters. Specifically, PI was found to be associated with SS, PT, and OH, whereas the spinal parameters LL1 and LL2 were found to be related to TK and SB. Between spine and pelvic parameters, LL1 and LL2 were found to be related to SS, PT, PI, and OH and in addition, SB was found to be related to TLK, LL1, and LL2. An analysis of relations between the symptoms and parameters revealed a positive correlation between the severities of symptoms and PT, OH, and TLK (r=0.300, p=.023; r=0.306, p=.020; r=0.289, p=.029, respectively).

CONCLUSIONS

A significant difference was observed in the sagittal spinopelvic parameters in the CP and normal control groups and was possibly related to the symptoms. The study shows that the evaluations of sagittal spinopelvic parameters could be useful during the treatment of disorders associated with CP.