Inter- and Intraobserver Reliability of Pelvic Obliquity Measurement Methods in Patients With Cerebral Palsy

Can postoperative Cobb and pelvic obliquity corrections be predicted using supine traction X-rays in non-ambulatory patients with cerebral palsy fused to L5? A case series study

PURPOSE

This study aimed to determine whether Cobb and pelvic obliquity corrections can be predicted using supine traction radiographs in patients with cerebral palsy (CP) who underwent posterior spinal fusion (PSF) from T2/3 to L5.

METHODS

From January 2010 to January 2020, 167 non-ambulatory patients with CP scoliosis underwent PSF using pedicle screws in two quaternary centers with a minimum of 2 years follow-up (FU). Radiological measurements and chart reviews were performed.

RESULTS

A total of 106 patients aged 15.6 ± 0.4 years were included. All patients had significant correction of the Cobb angle (MC), pelvic obliquity (PO), thoracic kyphosis (TK), and lumbar lordosis (LL) without loss of correction at the last FU (LFU). Curve flexibility was significantly correlated with Cobb correction (δMC) immediately postoperatively (p < 0.0001, r = 0.8950), followed by the amount of correction in pelvic obliquity under traction (δPOT) (p = 0.0252, r = 0.2174). For correction in PO (δPO), the most significant variable was δPOT (p < 0.0001, r = 0.7553), followed by curve flexibility (p = 0.0059, r = 0.26) and the amount of correction in Cobb under traction (p = 0.0252, r = 0.2174).

CONCLUSIONS

Cobb and PO corrections can be predicted using supine traction films for non-ambulatory CP patients treated with PSF from T2/3 to L5. The variables evaluated were interconnected, reinforcing preoperative planning for these patients. Comparative large-scale studies on patient-related clinical outcomes are required to determine whether this predicted correction is associated with improved surgical outcomes and reduced complication rates.

LEVEL OF EVIDENCE

IV.

Intraobserver and Interobserver Reliability of Pelvic Obliquity Measurement Methods in Patients With Idiopathic Scoliosis

BACKGROUND

Despite the importance of the assessment of pelvic obliquity, especially in the planning of surgery, there is no consensus on the pelvic obliquity measurements. The purpose of this study is to assess the intraobserver and interobserver reliability of 4 different pelvic obliquity measuring methods in patients with idiopathic scoliosis (IS): the Osebold, O'Brien, Maloney, and Allen&Ferguson methods.

METHODS

A retrospective cohort of 85 posteroanterior full-spine radiographs in the standing position of patients with IS involving the pelvic obliquity was evaluated by a team of 3 raters. The same researcher recorded the curve magnitude, apical vertebral rotation, Risser grade, curve pattern, and femoral head height difference. The pelvic obliquity angle was measured using the Osebold, O'Brien, Maloney, and Allen&Ferguson methods. The same graders were asked to regrade the same radiographs after at least 1 month.

RESULTS

The Osebold method showed the highest interobserver reliability with an ICC of 0.994 and 0.983. The Allen&Ferguson method had the lowest reliability with an ICC of 0.911 and 0.934, but all of the methods were considered having excellent reliability. The Osebold method also showed the highest intraobserver reliability, ranging from 0.909 to 0.997. The Allen&Ferguson method had the lowest intraobserver reliability, with a range of 0.741 to 0.960. Also, all observers preferred the Osebold Method. The observers reported that the Allen&Ferguson method was considered the most time-consuming method, while the least time-consuming method was specified as the Osebold method.

CONCLUSIONS

To the best of our knowledge, this study is the first to evaluate the intraobserver and interobserver reliability of pelvic obliquity among common measurement methods in patients with idiopathic scoliosis. All methods were evaluated as having excellent to good reliability in this study, but the Osebold method is the most reliable method of measuring pelvic obliquity on a frontal view radiograph in idiopathic scoliosis. The Osebold method is easier to use as it requires only the iliac crests to be visualized.

LEVEL OF EVIDENCE

Level III-Retrospective cohort study.

Bipolar Fusionless Versus Standard Fusion Surgery in Neuromuscular Scoliosis: A Two-center Comparative Study

STUDY DESIGN

Nonrandomized controlled cohort.

OBJECTIVE

To compare early results between bipolar fusionless construct (BFC) and single posterior fusion (SPF) surgery in neuromuscular scoliosis (NMS).

BACKGROUND

Surgical treatments for NMS have traditionally been characterized by high complication rates. A mini-invasive BFC was developed to reduce these risks while maintaining adequate curve reduction. There is, however, a current lack of studies comparing clinical and radiologic perioperative outcomes between both techniques.

METHODS

All patients surgically treated for NMS with to-pelvis construct between 2011 and 2021 at 2 centers were included and divided into 2 groups according to the surgical technique (BFC or SPF). Gender, age, main deformity region, etiology, preoperative and postoperative main curve magnitude and pelvic obliquity, surgery time, estimated blood loss and transfusion rates, length of hospital stay, the magnitude of main curve and pelvic obliquity correction, and early complications were compared. Quantitative data were compared through ANOVA or Mann-Whitney test. Analysis of qualitative outcomes was performed through Fisher exact test and logistic regressions. Kruskal-Wallis test was used to compare complications between groups.

RESULTS

Eighty-nine NMS patients were included: 48 in the SPF group and 41 in the BFC group. Surgery time (203 vs. 241 min), rate (32 vs. 52%) and severity of complications, unplanned returns to the operating room (15 vs. 39%), estimated blood loss (179 vs. 364 cc), and transfusion rates (27 vs. 73%) were lower in the BFC group ( P <0.05). There were no significant differences in age, maturity stage, preoperative curve magnitude, preoperative pelvic obliquity and postoperative curve, and pelvic obliquity correction between groups.

CONCLUSIONS

BFC may be a safer and less invasive option for NMS surgical treatment, resulting in similar curve corrections while significantly decreasing the number and severity of complications as well as intraoperative blood loss when compared with SPF.

LEVEL OF EVIDENCE

Level -lll.

Distal level in scoliosis surgery for non-ambulatory patients with cerebral palsy: is L5 an option? A case series study

PURPOSE

This study aimed to determine the radiographic outcomes of patients with cerebral palsy (CP) who underwent posterior spinal fusion from T2/3 to L5 at two quaternary hospitals.

METHODS

From January 2010 to January 2020, 167 non-ambulatory patients with CP scoliosis underwent posterior spinal fusion using pedicle screws from T2/3 to L5 in both centers, with a minimum of 2 years follow-up (FU). Radiological measurements and chart reviews were performed.

RESULTS

A total of 106 patients aged 15.6 ± 0.4 years were included. None of the patients was lost to FU. All patients had significant correction of the Cobb angle (MC) and pelvic obliquity (PO), thoracic kyphosis (TK), and lumbar lordosis (LL), without loss of correction at the last FU (LFU). The mean values for preoperative, immediate postoperative, and LFU were MC 93.4°, 37.5°, and 42.8°; PO 25.8°, 9.9°, and 12.7°; TK 52.2°, 44.3°, and 45°; and LL - 40.9°, - 52.4°, and - 52.9°, respectively. Higher residual PO at LFU was associated with more severe MC and PO baselines, lower implant density, and an apex located at L3.

CONCLUSIONS

CP scoliosis and PO can be corrected, and this correction is maintained over time with posterior spinal fusion using pedicle screws, with L5 as the lowest instrumented vertebra. Larger preoperative MC and PO values associated with the apex at L3 appear to be related to residual PO. Comparative large-scale studies of patient-related clinical outcomes are required to determine whether this intervention is associated with improved surgical outcomes and reduced complication rates.

LEVEL OF EVIDENCE

IV.

Distal fusion level, complications, and reoperations in individuals with cerebral palsy undergoing surgery for scoliosis

PURPOSE

To compare radiological outcome, complications and reoperations in individuals with cerebral palsy and scoliosis fused to the fifth lumbar vertebra (L5), the sacrum, or the ilia.

METHODS

208 individuals were identified in the national quality registry Swespine. Lowest level of fusion was L5 in 58, the sacrum in 92, and the ilia in 58 individuals. A subanalysis on 58 matched pairs operated to L5 or the pelvis (sacrum = 42, ilia = 16) with similar pelvic obliquity (± 5°) was performed.

RESULTS

The median (interquartile range) follow-up for the last radiograph was 1.7 (1.7) years and for reoperations 6.0 (5.9) years. Preoperatively, median Cobb angle of the major curve was 65° (23°) in the L5 group, 68° (28°) in the sacrum group, and 78° (25°) in the ilia group (p = 0.006). Preoperative median pelvic obliquity according to Maloney was 16° (19°), 21° (13°), and 27° (28°), respectively (p = 0.004). Immediate postoperative Cobb angles were 28° (18°), 28° (16°), and 32° (25°), respectively (p = 0.11). Immediate postoperative pelvic obliquity was 7° (10°), 7° (8°), and 8° (10°), respectively (p = 0.28). The median change in pelvic obliquity from the first to the last postoperative radiograph was - 5° (7°), - 3° (6°), - 3° (6°), respectively (p = 0.55). 7 (12%), 11 (12%), and 7 (12%) patients required at least one reoperation (p = 1.0), respectively. In the matched analysis, no significant differences in the radiological outcomes were found (all p ≥  0.38).

CONCLUSIONS

Maintained curve and pelvic obliquity correction with no significant difference in complication and reoperation rates were found irrespective of distal fusion level.

Progressive scoliosis associated with microphthalmia with limb anomalies: A case report

RATIONALE

Microphthalmia with limb anomalies is a rare, autosomal recessive, multiple congenital anomaly syndrome. Patients with this syndrome particularly present with monocular or bilateral anophthalmia/microphthalmia and distal limb anomalies. However, details regarding associated spinal deformities have not been fully elucidated.

PATIENT CONCERNS

A 12-year-old girl initially presented with progressive scoliosis, who was previously diagnosed with microphthalmia with limb anomalies. However, 4 years after the initial visit, the scoliosis deformity gradually progressed. The patient and family requested the surgical treatment to preserve standing/sitting balance.

DIAGNOSES

She was diagnosed with microphthalmia with limb anomalies and progressive scoliosis.

INTERVENTIONS

A posterior corrective fusion surgery (including a pelvic fusion) was performed to prevent future standing/sitting imbalance.

OUTCOMES

Significant improvement of spinal deformity was observed, with no adverse events.

LESSONS

This report demonstrated a case of progressive scoliosis associated with microphthalmia with limb anomalies. A posterior corrective spinal fusion was effective to preserve standing/sitting balance. To the best of our knowledge, this is the first report of surgical treatment of progressive scoliosis associated with microphthalmia with limb anomalies.

Automatic deep learning-based assessment of spinopelvic coronal and sagittal alignment

PURPOSE

The purpose of this study was to evaluate an artificial intelligence (AI) solution for estimating coronal and sagittal spinopelvic alignment on conventional uniplanar two-dimensional whole-spine radiograph.

MATERIAL AND METHODS

This retrospective observational study included 100 patients (35 men, 65 women) with a median age of 14 years (IQR: 13, 15.25; age range: 3-64 years) who underwent conventional uniplanar two-dimensional whole-spine radiograph in standing position between January and July 2022. Ten most commonly used spinopelvic coronal and sagittal parameters were retrospectively measured without AI by a junior radiologist and approved or adjusted by a senior musculoskeletal radiologist to reach final measurements. Final measurements were used as the ground truth to assess AI performance for each parameter. AI performances were estimated using mean absolute errors (MAE), intraclass correlation coefficient (ICCs), and accuracy for selected clinically relevant thresholds. Readers visually classified AI outputs to assess reliability at a patient-level.

RESULTS

AI solution showed excellent consistency without bias in coronal (ICCs ≥ 0.95; MAE ≤ 2.9° or 1.97 mm) and sagittal (ICCs ≥ 0.85; MAE ≤ 4.4° or 2.7 mm) spinopelvic evaluation, except for kyphosis (ICC = 0.58; MAE = 8.7°). AI accuracy to classify low Cobb angle, severe scoliosis or frontal pelvic asymmetry was 91% (95% CI: 85-96), 99% (95% CI: 97-100) and 94% (95% CI: 89-98), respectively. Overall, AI provided reliable measurements in 72/100 patients (72%).

CONCLUSION

The AI solution used in this study for combined coronal and sagittal spinopelvic balance assessment provides results consistent with those of a senior musculoskeletal radiologist, and shows potential benefit for reducing workload in future routine implementation.

Hip Displacement Does Not Change After Pelvic Obliquity Correction During Spinal Fusion in Children With Cerebral Palsy

BACKGROUND

Children with cerebral palsy (CP) frequently develop both neuromuscular hip dysplasia and scoliosis, and occasionally, the timing of the worsening of both of these pathologies is concurrent. The question as to whether the hip or spine should be addressed first in CP remains controversial, with the majority of evidence being "expert opinion." The purpose of this project was to determine the impact of posterior spinal fusion (PSF) on the change in hip displacement for children with CP without previous reconstructive hip surgery.

METHODS

This was an Institutional Review Board-approved study that observed 67 patients from 2004 to 2018. Inclusion criteria included children with CP, 18 years of age and younger, Gross Motor Function Classification System IV and V, undergoing PSF at a single tertiary care children's hospital with a minimum 2-year follow-up. The primary outcome was the change in hip displacement as quantified by the migration percentage (MP). The hip with the highest MP (worst hip) at the spine preoperative analysis were included for analysis. Triradiate cartilage (TRC) status and pelvic obliquity correction were analyzed with multivariate analysis.

RESULTS

Sixty-seven patients were included for analysis, with a mean age of 12.5±2.3 years. The mean major curve angle of the major curve was 77±23 degrees and the mean preoperative pelvic obliquity was 21±12 degrees. There was no statistically significant change in MP after PSF from a mean preoperative value of 41±27%, to a mean postoperative value of 41±29% at the last follow-up, (P=0.76) The mean follow-up time was 4.1±2.7 years. TRC status (P=0.52) and the severity of pelvic obliquity (P=0.10) did not statistically impact the change in MP after PSF.

CONCLUSION

PSF did not influence-either negatively or positively-the progression of hip displacement in children with CP, regardless of pelvic obliquity correction or TRC status. The lack of deterioration in hip displacement post-PSF, however, may suggest a protective effect of spine surgery.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Restoring femoral medial offset could reduce pelvic obliquity following primary total hip arthroplasty, an observational study

BACKGROUND

Since femoral and horizontal offsets may be contributing factors to hip and pelvic balance, this study seeks to determine whether there is a correlation between pelvic obliquity (PO) after unilateral total hip arthroplasty (THA) and horizontal/vertical offset differences of the replaced and contralateral natural joints.

METHODS

A cross-sectional study was performed on adult patients who underwent unilateral THA between 2017 and 2020. An expert orthopaedic resident measured PO angles and offset parameters. "Delta medial offset" is considered medial offset of the replaced hip minus the medial offset of the contralateral side. "Absolute delta medial offset" is considered the absolute value of the "Delta medial offset."

RESULTS

Finally, 133 patients were included in the study with a mean (SD) age of 45.3 ± 14.8 years and 57.9% female. The PO values (median, IQR) changed from 3.2 (1.7-5.7) before THA to 3.0 (1.50-5.6) after THA, not significantly decreased (P = 0.31). The PO after THA is significantly correlated with PO before THA (correlation coefficient of 0.457, P < 0.001), the delta medial offset after THA (correlation coefficient of - 0.24, P = 0.006), and the absolute delta medial offset after THA (correlation coefficient of 0.284, P = 0.001). The amount of changes of delta medial offset, before and after surgery, was not significantly correlated to PO or PO changes after surgery.

CONCLUSION

PO before the THA and medial offset discrepancy after THA are two important contributing factors for post-operative PO. Restoring the medial offset of the affected side and lowering the delta medial offset between the two sides can significantly decrease post-operative PO.

Association of the joint line orientation angle of the contralateral limb with the alignment change of the unilateral and bilateral opening-wedge high tibial osteotomy

PURPOSE

This study aimed to evaluate and compare unilateral and bilateral open-wedge high tibial osteotomy (OWHTO) using mid-term serial assessment of clinical and radiological outcomes, especially focussing on coronal lower extremity alignment.

METHODS

Serial radiological assessments were performed in 40 patients (80 knees) with bilateral OWHTO and 49 patients (49 knees) with unilateral OWHTO. Both groups were further divided into four subgroups to compare each limb (unilateral involved and non-involved limbs and bilateral primarily and secondarily treated limbs). Radiological and clinical outcomes were evaluated and compared among the four groups. For the alignment change assessment, the pelvic tilt angle (PTA), weight-bearing line ratio (WBLR), joint line orientation angle (JLOA), medial proximal tibia angle (MPTA), joint line convergence angle (JLCA), distal tibia articular angle (DTAA), and talar inclination (TI) were measured pre- and postoperatively at 3, 6, and 12 months and annually thereafter. Student's t-test, one-way repeated-measures analysis of variance, and correlation analysis were used to compare the groups.

RESULTS

Patients in the unilateral and bilateral OWHTO groups had similar postoperative radiological and clinical outcomes. Each unilaterally involved limb and primarily treated bilaterally involved limb were negatively affected by the contralateral limb with respect to increased JLOA during the postoperative period (unilateral OWHTO group: r = -0.350, p = 0.023; bilateral OWHTO group: r = -0.520, p = 0.005). The correction change of the ankle parameters in the secondarily treated limb showed greater varus alignment than the primarily treated limb after bilateral OWHTO (DTAA (0.1 ± 3.0 vs. -0.5 ± 3.8°, p = 0.014) and TI (0.9 ± 3.2° vs. -0.3 ± 2.9, p = 0.001)).

CONCLUSION

Unilateral and bilateral OWHTOs shared similar postoperative radiological and clinical outcomes. Alignment changes of the unilateral OWHTO and the primarily treated limb of the bilateral OWHTO were associated with the JLOA of the contralateral limb.

LEVEL OF EVIDENCE

Cohort study; Level III.

Understanding the role of pelvic obliquity and leg length discrepancy in adult spinal deformity patients with coronal malalignment: unlocking the black box

OBJECTIVE

This study had 3 objectives: 1) to describe pelvic obliquity (PO) and leg-length discrepancy (LLD) and their relationship with coronal malalignment (CM); 2) to report rates of isolated PO and PO secondary to LLD; and 3) to assess the importance of preoperative PO and LLD in postoperative complications, readmission, reoperation, and patient-reported outcomes.

METHODS

Patients undergoing surgery (≥ 6-level fusions) for adult spinal deformity at a single institution were reviewed. Variables evaluated were as follows: 1) PO, angle between the horizontal plane and a line touching bilateral iliac crests; and 2) LLD, distance from the head to the tibial plafond. Coronal vertical axis (CVA) and sagittal vertical axis measurements were collected, both from C7. The cutoff for CM was CVA > 3 cm. The Oswestry Disability Index (ODI) was collected preoperatively and at 2 years.

RESULTS

Of 242 patients undergoing surgery for adult spinal deformity, 90 (37.0%) had preoperative CM. Patients with preoperative CM had a higher PO (2.8° ± 3.2° vs 2.0° ± 1.7°, p = 0.013), a higher percentage of patients with PO > 3° (35.6% vs 23.5%, p = 0.044), and higher a percentage of patients with LLD > 1 cm (21.1% vs 9.8%, p = 0.014). Whereas preoperative PO was significantly positively correlated with CVA (r = 0.26, p < 0.001) and maximum Cobb angle (r = 0.30, p < 0.001), preoperative LLD was only significantly correlated with CVA (r = 0.14, p = 0.035). A total of 12.2% of patients with CM had significant PO and LLD, defined as follows: PO ≥ 3°; LLD ≥ 1 cm. Postoperatively, preoperative PO was significantly associated with both postoperative CM (OR 1.22, 95% CI 1.05-1.40, p = 0.008) and postoperative CVA (β = 0.14, 95% CI 0.06-0.22, p < 0.001). A higher preoperative PO was independently associated with postoperative complications after multivariate logistic regression (OR 1.24, 95% CI 1.05-1.45, p = 0.010); however, 2-year ODI scores were not. Preoperative LLD had no significant relationship with postoperative CM, CVA, ODI, or complications.

CONCLUSIONS

A PO ≥ 3° or LLD ≥ 1 cm was seen in 44.1% of patients with preoperative CM and in 23.5% of patients with normal coronal alignment. Preoperative PO was significantly associated with preoperative CVA and maximum Cobb angle, whereas preoperative LLD was only associated with preoperative CVA. The direction of PO and LLD showed no consistent pattern with CVA. Preoperative PO was independently associated with complications but not with 2-year ODI scores.

The radiographic assessments of spino-pelvic compensation using IoT-based real-time ischial pressure adjustment

In malalignment syndrome, the spino-pelvic alignment correction with foot orthotics can be applied only to a standing position in the coronal plane. Considering the fact that the average time Koreans spend sitting in a chair is 7.5 hours per day, studies on spino-pelvic correction in sitting position is needed. The purpose of this study is to investigate the pressure changes and radiographic assessment of spino-pelvic alignment using a chair equipped with a height-adjustable seat-plate. This study was conducted on 30 participants with spinopelvic malalignment. All participants were subjected to measure buttocks interface pressure while seated using a smart chair in three consecutive steps: 1. on initial seated, 2. on balancing seated, and then. 3. on 1 hour balancing seated. Radiographically, the five spino-pelvic parameters such as shoulder height differences (SHD), iliac crest height differences (ICHD), leg length discrepancy (LLD), pelvic oblique angle (POA), and coronal imbalance were analyzed to investigate the effect of pelvic imbalance compensation on spino-pelvic alignment. Statistical analysis was performed using ANOVA and paired t test. The pressure discrepancy improvement between buttocks from 36.4 ± 32.3 mm on initial seated to 15.7 ± 20.3 mm on balancing, 12.7 ± 10.9 mm on 1hr balancing seated (Ω, P = .008). The radiographic results of pelvic imbalance compensation during seated show a statistical improvement of average SHD (from −0.9 to −0.8 mm, P = .005) and average ICHD (from 9.5 to 2.5 mm, P = .037). For a standing posture after use of smart chair, average SHD value (−3.0 to −1.0 mm, P = .005), ICHD (from 1.8 to 0.8 mm, P = .016), and average LLD value (0.8–0.1 mm, P = .033) were statistically significant improved. Spine-pelvic malalignment can be improved by individually customized pelvic compensation using balanced seat plate height adjustments under the real-time pressure sensing and monitoring on the buttocks while seated.

COMPARISON BETWEEN TWO METHODS OF MEASURING PELVIC OBLIQUITY IN CEREBRAL PALSY AND MYELOMENINGOCELE

ABSTRACT Objective: To evaluate the intra- and inter-observer reproducibility of the evaluation of the pelvic obliquity (PO) in patients with neuro-muscular deformities via the method that uses the iliac crests and the method that uses the upper endplate of S1 and to determine whe ther there is a relationship between the methods. Methods: The digitized panoramic radiographies of thirty patients with cerebral paralysis or myelomeningocelein outpatient monitoring were evaluated by four examiners: two experienced spinal surgeons and two fellows. Two radiographs were excluded because analysis was impossible. All exams were obtained in accordance with the periodic monitoring protocol in the sitting position, using digitized film and a film-focus distance of 110 cm Results: High intra- and inter-observer agreement was observed both for method that uses the iliac crests and the method that evaluates the S1 endplate. However, no significant relationship between the two methods was observed. Conclusions: The methods evaluated had good reproducibility and agreement among the observers. It was confirmed that, on account of the existent linear relation, it is possible to estimate the value of the iliac crest method knowing the value obtained by the S1 plateau multiplied by 0.76. There was no agreement between the iliac crest and S1 plateau PO evaluation methods. Level of evidence IV; Retrospective cross-sectional study.

Pelvic obliquity associated with neuromuscular scoliosis in cerebral palsy: cause and treatment

STUDY DESIGN

Literature Review.

OBJECTIVE

Review the etiology, clinical manifestations, diagnosis, and treatment of pelvic obliquity in cerebral palsy patients with neuromuscular scoliosis. Neuromuscular scoliosis (NMS) in cerebral palsy (CP) patients is rapidly progressive and often leads to an imbalance in musculoskeletal mechanics that extends to the pelvis. A horizontal misalignment of the pelvis in the frontal plane known as pelvic obliquity (PO) is a common finding in this population. When untreated, PO can exacerbate the back pain, postural strain, and walking difficulties experienced by these patients. Establishing the manifestation and treatment plan for PO in the setting of NMS can provide valuable insight for diagnosis and management.

METHODS

A comprehensive literature review was performed on the etiology, clinical manifestations, diagnosis, and treatment of pelvic obliquity in the setting of NMS in CP. The advantages and limitations of measurement and treatment options were evaluated.

RESULTS

PO is categorized into suprapelvic, infrapelvic, and intrapelvic causes, each presenting with a unique pattern of pathology. NMS in CP with hip contractures and structural deformities fall into these categories. The Maloney and O'Brien methods of pelvic measurement have demonstrated superior utility and are recommended for clinical diagnosis. The management of PO in NMS patients is focused on the cause of malalignment, with posterior fusion, contracture release, and osteotomy encompassing the mainstay of treatment.

CONCLUSION

PO is commonly found in patients with NMS in cerebral palsy. There is currently no standard method for determining the PO angle. Interventions designed to reduce scoliotic curves and release tissue contractures can level the pelvis and restore proper alignment of the spine and sacrum in the coronal plane in these patients. Further understanding of the causes of PO in NMS, as well as the establishment of a standardized measuring technique and diagnostic parameters will allow for more effective treatment options and improve outcomes in patients with CP.

LEVEL OF EVIDENCE

N/A.

Correlation of Pulmonary Function to Novel Radiographic Parameters of Collapsing Parasol Deformity in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a neuromuscular disease with manifestations of scoliosis, pulmonary function decline, and, uniquely, collapse of the ribs. Methods to quantify rib deformity and its impact on pulmonary function are sparse. The authors propose new radiographic measurements to quantify the aspect of SMA known as collapsing parasol deformity and correlate these measurements with pulmonary function. Twenty-eight full-spine radiographs of pediatric SMA patients were measured twice by 3 independent investigators, with 2 weeks separating each measurement. Radiographic measurements, demographics, spirometry results, and assisted ventilation rating were obtained. Twenty-one patients with spirometry metrics were assessed to correlate pulmonary function and spinal measurements. The intrarater intraclass correlation coefficient (ICC) for the measurements ranged from 0.706 to 0.99, and the interrater ICC ranged from 0.64 to 0.97. Eighteen of 19 variables had ICC values greater than 0.75 for inter- and intrarater reliability. Twenty-one patients with forced expiratory volume in 1 second and forced vital capacity were assessed in terms of these measurements. Ratio of the concave hemithoracic width at T6/convex hemithoracic width at T6 (P=.004) and ratio of convex vertical rib displacement at the apical rib/concave vertical rib displacement (P=.021) were both significantly correlated with decreased pulmonary function. No significant correlation was found examining the average vertical rib displacement at the apical rib. High inter-and intrarater reliability can be obtained in a variety of spinal measurements of SMA patients. Various measurements are correlated to diminished pulmonary function, specifically variables showing asymmetric changes in the chest cavity. [Orthopedics. 2021;44(2):e287-e293.].

The Variability of Pelvic Obliquity Measurements in Patients with Neuromuscular Scoliosis

Pelvic obliquity (PO), or pelvic alignment in the coronal plane, is an important radiographic parameter to indicate fusion levels and judge success of scoliosis correction in patients with neuromuscular scoliosis. There are multiple commonly used techniques to measure PO that have good to excellent interrater and intrarater reliability, but these different methods yield inconsistent values when used on the same radiograph. This study evaluates the inconsistency in the magnitude of PO measurements for patients with neuromuscular scoliosis among 5 common measurement techniques.

Outcomes of Vertical Expandable Prosthetic Titanium Ribs in Children With Early-Onset Scoliosis Secondary to Cerebral Palsy

Purpose

Patients who have neuromuscular scoliosis, such as cerebral palsy (CP), often develop spinal deformities that negatively impact quality of life. The vertical expandable prosthetic titanium rib (VEPTR) was designed for thoracic insufficiency syndrome (TIS), but it has also been utilized in patients with CP with restrictive lung disease and spine deformity. Few studies report on VEPTRs in neuromuscular scoliosis; however, none reports on their utilization specifically in patients with CP. Our purpose was to assess if VEPTRs can improve spinal deformity and TIS in these patients.

Methods

A retrospective chart review was performed of all patients with CP and scoliosis treated with a VEPTR between 2008 and 2017. Eight patients were eligible for this study. The mean follow-up was four years. Outcomes evaluated were Cobb angle, pelvic obliquity, space available for lung ratio (SAL), T1-S1 height, and complication rates. A p-value of less than 0.05 was used for statistical significance.

Results

There were significant postoperative improvements in Cobb angle, pelvic obliquity, and T1-S1 height, but no statistical difference in SAL. Prior to final fusion, the mean number of VEPTR lengthening procedures was 3. The mean time from index surgery to final fusion was 3.7 years. The most common complications were infection (62.5%) and wound dehiscence (25%). Only 25% of patients did not have a complication.

Conclusion

VEPTRs demonstrated significant improvement in almost all parameters and may be valuable in improving TIS in patients with CP. The complication and reoperation rates were similar to those of VEPTRs used for other pathological conditions.

Spine deformities in patients with cerebral palsy; the role of the pelvis

INTRODUCTION

Progressive neuromuscular spinal deformities with pelvic obliquity and loss of sitting balance are typical features of severely affected patients with cerebral palsy. The pelvis represents the key bone between the spine and the lower extremity when it comes to deciding whether and when to operate and if spine or hip surgery first is beneficial. The pelvis can be looked at as the lowest vertebra and as the rooftop of the lower extremities.

BIOMECHANICAL CONSIDERATIONS

To allow for a normal spinal shape, the pelvis needs to be horizontal in the frontal plane and mildly anterior tilted in the sagittal plane, less for sitting and more for standing. Any abnormal pelvic position requires spinal compensation and challenges the equilibrium control of the individual. Both anatomical neighbourhoods - the spine and the hip joints - have to be considered when spinal deformities, hip instability and contractures evolve, in conservative therapy (bracing, physiotherapy, seating in the wheelchair) and when surgical interventions are weighed out against each other.

SURGICAL CONSIDERATIONS

Multiple anatomical factors such as sagittal profile and pelvic orientiation, pelvic transverse plane asymmetries and lumbosacral malformations have to be considered in case the pelvis is instrumented with sacral and iliac screws. Rotational deformities and asymmetries of the pelvic bones make the safe insertion of long screws challenging. Advantages of primary pelvic fixation include correction of pelvic obliquity, especially considering the lever arm of the whole spinal construct. The risk of revision surgery due to progression of distal curves is also reduced. Disadvantages of pelvic fixation include the complexity of the additional intervention, which may result in longer operating times, increased risk of blood loss, infection and hardware malpositioning.

Classification of coronal imbalance in adult scoliosis and spine deformity: a treatment-oriented guideline

INTRODUCTION

In adult spinal deformity (ASD), sagittal imbalance and sagittal malalignment have been extensively described in the literature during the past decade, whereas coronal imbalance and coronal malalignment (CM) have been given little attention. CM can cause severe impairment in adult scoliosis and ASD patients, as compensatory mechanisms are limited. The aim of this paper is to develop a comprehensive classification of coronal spinopelvic malalignment and to suggest a treatment algorithm for this condition.

METHODS

This is an expert's opinion consensus based on a retrospective review of CM cases where different patterns of CM were identified, in addition to treatment modifiers. After the identification of the subgroups for each category, surgical planning for each subgroup could be specified.

RESULTS

Two main CM patterns were defined: concave CM (type 1) and convex CM (type 2), and the following modifiers were identified as potentially influencing the choice of surgical strategy: stiffness of the main coronal curve, coronal mobility of the lumbosacral junction and degeneration of the lumbosacral junction. A surgical algorithm was proposed to deal with each situation combining the different patterns and their modifiers.

CONCLUSION

Coronal malalignment is a frequent condition, usually associated to sagittal malalignment, but it is often misunderstood. Its classification should help the spine surgeon to better understand the full spinal alignment of ASD patients. In concave CM, the correction should be obtained at the apex of the main curve. In convex CM, the correction should be obtained at the lumbosacral junction. These slides can be retrieved under Electronic Supplementary Material.