Endoscopic Anatomy of the Skull Base.

Presently, endoscopic skull base surgery has undergone significant advancements since its inception over two decades ago. Nevertheless, it is imperative to underscore that the fundamental basis of all surgical procedures lies in the meticulous understanding of anatomy, with particular emphasis on the ventral anatomy. This facet has recently garnered increased attention.Following the advancements in endoscopic skull base surgery techniques, this chapter will concentrate on the pertinent anatomical considerations that serve as key foundations for successful procedures. These considerations are categorized into two planes: the sagittal plane and the coronal plane.The sagittal plane is further subdivided into five distinct approaches, namely,(1) the transcribriform approach, (2) the transplanum approach, (3) the transsellar approach, (4) the transclival approach, and (5) the transodontoid approach.On the other hand, the coronal plane is delineated into seven specific zones to facilitate comprehension and potential applications: (1) the petrous apex approach, (2) the intrapetrous approach, (3) the suprapetrous approach, (4) the cavernous sinus approach, (5) the infratemporal approach, (6) the medial condyle approach, and (7) the jugular foramen approach.By organizing the anatomical aspects in this systematic manner, the information provided becomes more accessible, fostering a comprehensive understanding of the subject matter for potential future application.

Analysis of Spinal-Pelvic Sagittal Plane Parameters in Patients with Lumbar Vertebral Posterior Ring Apophysis Separation.

OBJECTIVE: To investigate the characteristics of the spinal-pelvic sagittal sequence in patients with lumbar vertebral posterior ring apophysis separation (PRAS). METHODS: A retrospective analysis was conducted on 119 hospitalized patients with PRAS, and 119 adults without symptoms of low back and leg pain were selected as the control. General data and spinal-pelvic sagittal parameters were collected and analyzed. RESULTS: Compared to the control group, the pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL), and thoracic kyphosis of the PRAS group were significantly lower, while the pelvic tilt (PT), sagittal vertical axis, and PI minus LL were significantly higher. There was no significant difference in thoracolumbar kyphosis between the 2 groups. In patients with PRAS, the LL value of lumbar curvature was moderately correlated with thoracic kyphosis and SS, while PI, PT, and SS were pairwise correlated, indicating that the change in one parameter is often accompanied by simultaneous changes in other parameters if PRAS happens. The correlation between different parameters could provide guidance for the diagnosis of PRAS. In terms of LL type, the PRAS group was mainly of Roussouly type I, while the control group was mainly of type II, and the difference in the composition ratio was statistically significant. CONCLUSIONS: As reflected by the spinal-pelvic sagittal parameters, the patients with PRAS exhibited reduced thoracic and lumbar curvature, posterior PT, and fewer vertebral bodies involved in LL. These morphological characteristics indicate the changes of the mechanical structure of the spine.

Sagittal Plane Alignment for First Metatarsal Phalangeal Arthrodesis Correlated with Postoperative Function: What is the Optimal Position?

There have been many reports describing the proposed alignment of a first metatarsal phalangeal arthrodesis to obtain optimum function. Most of these recommendations are based upon historical and anecdotal evidence. Furthermore, there are few reports directly comparing alignment to patient reported function. We studied radiographic sagittal plane alignment in a group of 60 patients (80 feet) who had undergone a first metatarsal phalangeal joint arthrodesis (20 of the 60 had bilateral arthrodesis) to better understand how this component of the arthrodesis position translates to real world function. The patients in this study had completed a functional survey in 2022 at a mean of 28.4 (median 27.8; range 13.2-45.7) months with very high satisfaction for return to activities of daily living and recreational sports. We measured the sagittal plane position of the first metatarsal relative to the proximal phalanx in this cohort with known post operative activity data. We found that a mean (standard of deviation) sagittal plane angle (angle between the anatomic axis of the first metatarsal and the proximal phalanx) of 15.4 (SD 7.4) degrees and a proximal phalanx head to ground height of 12.7 (SD 3.3) mm was present in this group. Comparing the functional and positional results we conclude that this sagittal plane position provides a good recommendation for alignment.

The Role of Osteotomy in Anterior Cruciate Ligament Reconstruction.

Coronal and sagittal plane knee malalignments have been shown to increase the forces on anterior cruciate ligament (ACL) grafts after ACL reconstruction (ACLR). Studies have shown the benefit of high tibial osteotomy to address coronal and sagittal imbalance in revision ACLR. The purpose of this article is to further describe the use of osteotomy by reviewing preoperative planning, indications, techniques, and outcomes of high tibial opening and closing wedge as well as anterior tibial closing wedge osteotomies in the setting of ACLR.

Automatic extraction of facial median sagittal plane for patients with asymmetry based on the EDMA alignment algorithm.

BACKGROUND: We aimed to establish a novel method for automatically constructing three-dimensional (3D) median sagittal plane (MSP) for mandibular deviation patients, which can increase the efficiency of aesthetic evaluating treatment progress. We developed a Euclidean weighted Procrustes analysis (EWPA) algorithm for extracting 3D facial MSP based on the Euclidean distance matrix analysis, automatically assigning weight to facial anatomical landmarks. METHODS: Forty patients with mandibular deviation were recruited, and the Procrustes analysis (PA) algorithm based on the original mirror alignment and EWPA algorithm developed in this study were used to construct the MSP of each facial model of the patient as experimental groups 1 and 2, respectively. The expert-defined regional iterative closest point algorithm was used to construct the MSP as the reference group. The angle errors of the two experimental groups were compared to those of the reference group to evaluate their clinical suitability. RESULTS: The angle errors of the MSP constructed by the two EWPA and PA algorithms for the 40 patients were 1.39 ± 0.85°, 1.39 ± 0.78°, and 1.91 ± 0.80°, respectively. The two EWPA algorithms performed best in patients with moderate facial asymmetry, and in patients with severe facial asymmetry, the angle error was below 2°, which was a significant improvement over the PA algorithm. CONCLUSIONS: The clinical application of the EWPA algorithm based on 3D facial morphological analysis for constructing a 3D facial MSP for patients with mandibular deviated facial asymmetry deformity showed a significant improvement over the conventional PA algorithm and achieved the effect of a dental clinical expert-level diagnostic strategy.

Assessing the validity of two-dimensional video analysis for measuring lower limb joint angles during fencing lunge.

Introduction: The fencing lunge (lunge), characterized by minimal body rotation, offers a movement well-suited for 2D video analysis. However, to the best of our knowledge, the validity of 2D video analysis for fencing has not been verified. This study aimed to validate 2D video analysis by comparing lower limb joints (hip, knee, and ankle joints) angles during lunge using both 2D video analysis and 3D motion analysis methods. Methods: Twenty-two male fencers performed lunge trials that were simultaneously recorded using eight motion capture cameras (Qualisys Miqus M1) and two digital video cameras (Sony AX-450 and AX450a). Results: The 2D video analysis results exhibited an extremely large correlation in knee joint angles of the front and rear legs in the sagittal with those from 3D motion analysis (r = 0.93-0.99). However, while a robust correlation was found between the ankle joint angles of the front and rear legs (r = 0.82-0.84), a large bias was also observed (-5.23° to -21.31°). Conversely, for the hip joints of the rear leg, a moderate correlation (r = 0.31) and a large bias (-10.89°) were identified. Conclusions: The results of this study will contribute to the development of coaching using 2D video analysis in competition settings because such analysis can be a useful alternative to 3D motion analysis when measuring the knee joint angle of the front leg and rear leg in the sagittal plane. However, for the ankle joint angle, further research on the optimal shooting position and height of the digital video camera is needed, whereas for the hip joint angle, 3D motion analysis is recommended at this time.

Evaluating the Accuracy of Upper Limb Movement in the Sagittal Plane among Computer Users during the COVID-19 Pandemic.

(1) Background: The most common musculoskeletal pathology among healthcare professionals is neck and/or shoulder pain. The aim of this study was to determine the dominant upper limb functionality concerning the ability to replicate a given movement pattern among employees reporting neck or upper limb pain while using a computer during the COVID-19 pandemic. (2) Methods: The study was conducted from March to April 2021 on a group of 45 medical employees who used a computer workstation for 4 to 6 h of their working time. In the design of this study, three study groups were created: a group of patients with pain syndrome of segment C5/C7 of the spine, a group of patients with shoulder pain syndrome, and a control group of healthy volunteers. (3) Results: The examined groups significantly differed in the correctness of performing the given movement (p = 0.001) and the minimum value of inclination during the exercise session (p = 0.026), as well as the maximum lowering (p = 0.03) in relation to the control group. (4) Conclusions: The VECTIS device can be used to assess the accuracy of reflecting the prescribed movement of the upper limb in rehabilitation programs for patients with cervical spine pain syndrome and shoulder pain syndrome.

Regression-Based Machine Learning for Predicting Lifting Movement Pattern Change in People with Low Back Pain.

Machine learning (ML) algorithms are crucial within the realm of healthcare applications. However, a comprehensive assessment of the effectiveness of regression algorithms in predicting alterations in lifting movement patterns has not been conducted. This research represents a pilot investigation using regression-based machine learning techniques to forecast alterations in trunk, hip, and knee movements subsequent to a 12-week strength training for people who have low back pain (LBP). The system uses a feature extraction algorithm to calculate the range of motion in the sagittal plane for the knee, trunk, and hip and 12 different regression machine learning algorithms. The results show that Ensemble Tree with LSBoost demonstrated the utmost accuracy in prognosticating trunk movement. Meanwhile, the Ensemble Tree approach, specifically LSBoost, exhibited the highest predictive precision for hip movement. The Gaussian regression with the kernel chosen as exponential returned the highest prediction accuracy for knee movement. These regression models hold the potential to significantly enhance the precision of visualisation of the treatment output for individuals afflicted with LBP.

Automated localization of mandibular landmarks in the construction of mandibular median sagittal plane.

OBJECTIVE: To use deep learning to segment the mandible and identify three-dimensional (3D) anatomical landmarks from cone-beam computed tomography (CBCT) images, the planes constructed from the mandibular midline landmarks were compared and analyzed to find the best mandibular midsagittal plane (MMSP). METHODS: A total of 400 participants were randomly divided into a training group (n = 360) and a validation group (n = 40). Normal individuals were used as the test group (n = 50). The PointRend deep learning mechanism segmented the mandible from CBCT images and accurately identified 27 anatomic landmarks via PoseNet. 3D coordinates of 5 central landmarks and 2 pairs of side landmarks were obtained for the test group. Every 35 combinations of 3 midline landmarks were screened using the template mapping technique. The asymmetry index (AI) was calculated for each of the 35 mirror planes. The template mapping technique plane was used as the reference plane; the top four planes with the smallest AIs were compared through distance, volume difference, and similarity index to find the plane with the fewest errors. RESULTS: The mandible was segmented automatically in 10 ± 1.5 s with a 0.98 Dice similarity coefficient. The mean landmark localization error for the 27 landmarks was 1.04 ± 0.28 mm. MMSP should use the plane made by B (supramentale), Gn (gnathion), and F (mandibular foramen). The average AI grade was 1.6 (min-max: 0.59-3.61). There was no significant difference in distance or volume (P > 0.05); however, the similarity index was significantly different (P < 0.01). CONCLUSION: Deep learning can automatically segment the mandible, identify anatomic landmarks, and address medicinal demands in people without mandibular deformities. The most accurate MMSP was the B-Gn-F plane.

Coronal plane in opportunistic screening of osteoporosis using computed tomography: comparison with axial and sagittal planes.

OBJECTIVE: To compare the coronal plane with axial and sagittal planes in opportunistic screening of osteoporosis using computed tomography (CT). MATERIALS AND METHODS: A total of 100 patients aged ≥ 50 years who underwent both lumbar spine CT and dual-energy X-ray absorptiometry within 3 months were included. Osteoporosis was diagnosed based on dual-energy X-ray absorptiometry results. The CT number was measured at the center of the vertebral body in coronal, axial, and sagittal planes. To compare the coronal plane with axial and sagittal planes in diagnosing osteoporosis, the areas under the receiver operating characteristic curve (AUC) were compared and intraclass correlation coefficient (ICC) was calculated. The optimal cutoff values were calculated using Youden's index. RESULTS: The AUC of the coronal plane (0.80; 95% confidence interval [CI], 0.71-0.89) was not significantly different from that of the axial plane (0.78; 95% CI, 0.68-0.87; P = 0.39) and that of the sagittal plane (0.78; 95% CI, 0.69-0.87; P = 0.68). Excellent concordance rates were observed between coronal and axial planes with ICC of 0.95 (95% CI, 0.92-0.96) and between coronal and sagittal planes with ICC of 0.93 (95% CI, 0.85-0.96). The optimal cutoff values for the coronal, axial, and sagittal planes were 110, 112, and 112 HU, respectively. CONCLUSION: The coronal plane does not significantly differ from axial and sagittal planes in opportunistic screening of osteoporosis. Thus, the coronal plane as well as axial and sagittal planes can be used interchangeably in measuring bone mineral density using CT.

Changes in lumbosacral sagittal plane parameters of L5/S1 disc herniation reabsorption / 中国组织工程研究

BACKGROUND:Previous studies have shown the correlation between lumbosacral sagittal plane parameters and natural absorption of lumbar disc herniation.However,the lumbosacral sagittal plane parameters included lumbar lordosis angle,lumbosacral joint angle,sacral inclination angle and many other parameters.The effects of each parameter on the natural absorption of the herniated disc were different.In addition,there are few studies on the reabsorption of a specific segment of intervertebral disc herniation at present,and most of the measured data are obtained from digital radiography or CT,while the correlation between lumbosacral sagittal plane parameters measured from MRI and reabsorption after L5/S1 intervertebral disc herniation is rarely reported. OBJECTIVE:To study the corresponding changes of lumbar sagittal plane parameters after L5/S1 intervertebral disc herniation reabsorption and to screen out the lumbosacral sagittal plane parameters with the most significant changes during intervertebral disc reabsorption. METHODS:Totally 57 patients with lumbar disc herniation who had complete MRI image data were selected and met the diagnostic criteria for lumbar disc herniation and only received non-surgical treatment for reabsorption of L5/S1 protrusion segments.MRI measured the protrusion area of the maximum protrusion plane in the coronal plane,lumbosacral sagittal plane parameters[lumbar curvature index,lumbar lordosis(α),L5/S1 disc angle(β),intervertebral height measurement,lumbosacral joint angle,sacral platform angle,sacral inclination angle,and lower lumbar lordosis angle].Besides,lumbosacral sagittal plane parameters were ranked in the importance of variables by random forest model in R software,and then significant variables were fitted with multiple linear regression.The changes between parameters before and after treatment were analyzed and compared by paired sample t-test. RESULTS AND CONCLUSION:(1)A total of 57 patients with L5/S1 lumbar disc herniation were included in this study,and the symptoms and imaging features of the patients were significantly relieved to a large extent.(2)Before treatment,there were 4 cases of grade 1,29 cases of grade 2 and 24 cases of grade 3 according to the Classification of Michigan State University.After treatment,there were 48 cases of grade 1 and 9 cases of grade 2.(3)The random forest model suggested that intervertebral height,lumbar curve index,sacral inclination angle,and lower lumbar lordosis angle changed significantly in L5/S1 disc herniation reabsorption,and the order of their change significance was lumbar curve index>intervertebral space height>sacral inclination angle>lower lumbar lordosis angle.(4)Lumbar curve index,lumbar lordosis and sacral platform angle increased,with statistical significance(P<0.05).There were no significant differences in disc angle,intervertebral height,lower lumbar lordosis angle,sacral inclination angle or lumbosacral joint angle(P>0.05).(5)Lumbar curvature index was the most significant parameter of the lumbosacral sagittal plane in herniated disc reabsorption.In addition,lumbar curve index,sacral inclination angle,and lower lumbar lordosis angle are commonly used clinically to describe the change of lumbar curvature,suggesting that L5/S1 disc herniation reabsorption is correlated with the change of lumbar curvature.It is indicated that in the treatment of lumbar disc herniation,a clinical cure can be achieved by improving or restoring the disordered lumbar curvature.

Decompression and fusion for degenerative lumbar spondylolisthesis affect sagittal disequilibrium of the spine / 中国组织工程研究

BACKGROUND:Lumbar decompression and fusion is the most effective surgical method to treat lumbar degenerative spondylolisthesis.In recent years,the sagittal balance of the spine has been widely considered the key factor to adjust the outcome of spinal surgery,and factors that can affect the sagittal balance of the spine indirectly affect the surgical effect and prognosis. OBJECTIVE:To summarize the risk factors that can affect the sagittal balance of the spine during decompression and fusion due to lumbar spondylolisthesis,and play a certain reference role in the surgical treatment of lumbar spondylolisthesis. METHODS:With"lumbar spondylolisthesis,the sagittal plane balance of the spine,surgical treatment,risk factors"as the Chinese search terms,and"lumbar spondylolisthesis,sagittal balance,risk factor"as the English search terms,PubMed,Springer,ScienceDirect,Wanfang,VIP and CNKI were searched respectively.The focus of the search was from January 2010 to January 2023,and a few classic long-term articles were included.Preliminary screening was conducted by reading the title and abstract.After excluding repetitive research in Chinese and English literature,low-quality journals and irrelevant literature,67 articles were finally included for review. RESULTS AND CONCLUSION:(1)Degenerative lumbar spondylolisthesis is an important factor causing spinal canal stenosis and lumbar instability,and is the main cause of low back pain and intermittent claudication.Lumbar decompression,fusion and internal fixation is an effective way to treat degenerative lumbar spondylolisthesis.(2)In the past,the treatment of degenerative lumbar spondylolisthesis with decompression,fusion and fixation focused on thorough exploration and release of nerve roots,reduction of spondylolisthesis and solid internal fixation,but less attention was paid to the balance of sagittal plane of the spine.(3)With the popularization of lumbar decompression,fusion and internal fixation,complications caused by the sagittal imbalance of the spine gradually increased,resulting in poor prognosis of patients and even increased risk of secondary surgery.(4)Previous studies have only discussed the correlation between lumbar sagittal plane parameters and spinal sagittal plane balance,but have not in-depth studied the relevant factors causing spinal sagittal plane imbalance.(5)Our results show that open lumbar fixation and fusion,complete reduction of spondylolisthesis,selection of thicker pedicle screws,selection of larger fusion cages,and autologous bone transplantation are beneficial factors for maintaining sagittal balance.The higher the number of fusion segments,the higher the level of fusion segments is,which is a risk factor for sagittal plane imbalance.

An MRI-only Three-dimensional Cephalometry Protocol based on the Integrated and Modular Architecture of the Human Head.

BACKGROUND: Currently, three-dimensional cephalometry measurements are mainly based on cone beam computed tomography (CBCT), which has limitations of ionizing radiation, lack of soft tissue information, and lack of standardization of median sagittal plane establishment. OBJECTIVES: This study investigated magnetic resonance imaging (MRI)-only based 3D cephalometry measurement based on the integrated and modular characteristics of the human head. METHODS: Double U-Net CycleGAN was used for CT image synthesis from MRI. This method enabled the synthesis of a CT-like image from MRI and measurements were made using 3D slicer registration and fusion. RESULTS: A protocol for generating and optimizing MRI-based synthetic CT was described and found to meet the precision requirements of 3D head measurement using MRI midline positioning methods reported in neuroscience to establish the median sagittal plane. An MRI-only reference frame and coordinate system were established enabling an MRI-only cephalometric analysis protocol that combined the dual advantages of soft and hard tissue display. The protocol was devised using data from a single volunteer and validation data from a larger sample remains to be collected. CONCLUSION: The reported method provided a new protocol for MRI-only cephalometric analysis of craniofacial growth and development, malformation occurrence, treatment planning, and outcomes.

Finite element analysis of Kirschner wire fixation for lateral condyle fracture in children in the sagittal plane.

Objective: This study aims to find the optimal arrangement of the Kirschner wire (K-wire) in the sagittal plane for fixation of a pediatric lateral condylar humeral fracture (Milch type II) by using finite element analysis (FEA). Methods: A model of lateral condyle fracture in a 6-year-old boy was developed, and an XYZ coordinate system was established based on this model. The YZ plane was defined as the sagittal plane to investigate the impact of the angle formed by the first and second K-wires on stability. Two configurations were studied for each angle: parallel and divergent. Evaluation indicators included the maximum displacement of the fracture fragment and the maximum von Mises stress in the pins and bone. Results: The model with a -60° angle showed the best performance in both evaluation indicators. The parallel and divergent pin configurations had different performances in each group. The displacement results for negative angles were similar, and this result was better than those for positive angles. Conclusion: We successfully created a model of pediatric lateral condyle humerus fracture (Milch type II) and performed K-wire fixation with varying sagittal plane configurations, combined with FEA. Our findings demonstrate that the angle of -60° between the two pins in the sagittal plane provided the highest level of stability, with divergent configurations proving superior to parallel pinning at this angle.

Is Posterior Femoral Neck Cortex an Obstacle in Achieving Sagittal Plane Balance of Uncemented Straight Femoral Stem?

Summary of Background Data: There is a paucity of the literature that aims to improve sagittal plane balance of femoral stem in hip arthroplasty. We have comparatively evaluated the effect of trimming the posterior cortex left in situ after femoral neck osteotomy and counter-clockwise rotation of starting awl with respect to their ability to achieve neutral alignment of femoral stem in sagittal plane. Questions/Purposes: (1) Which of the two techniques under reference is more reliable in achieving a sagittal plane balance of the femoral stem in the femoral canal? (2) Does either of the two techniques have the potential to adversely affect other parameters for the optimum placement of femoral stem? Patients and Methods: This prospective study involved a total of 60 patients (age group of 18 to 60 years) who underwent primary total hip arthroplasty (THA) through a standard posterolateral approach. They were randomized into groups (1) PNCT (n = 30): femoral canal preparation was done by posterior neck cortex trimming method; (2) CCRA (n = 30): femoral canal preparation was done by counter-clockwise rotation of starting awl. Postoperatively, radiographs and computed tomography were obtained and angle of femoral stem with the femoral canal in coronal and sagittal plane, femoral stem tip deviation in coronal and sagittal plane, anteversion of the femoral stem, duration of canal preparation and blood loss were analyzed between the two groups. Results: Based on our results, there is a significantly better sagittal alignment of the femoral stem within the femoral canal, both in terms of angle of the femoral stem with the femoral canal (p < 0.001) and the deviation of the femoral stem tip from the center of the medullary canal (p < 0.001) when the posterior neck cortex was trimmed. Canal preparation by trimming the posterior neck cortex took a mean of 11.93 min (range 8-15 min) against the mean duration of 6.87 min (range; 5 min to 9 min) in the other group (p < 0.001). Conclusion: Trimming the posterior femoral neck cortex after neck osteotomy results in better sagittal plane balance of uncemented straight femoral stem. Level of Evidence: III.

Creation and Evaluation of a Severity Classification of Hyperkyphosis and Hypolordosis for Exercise Therapy.

The rise in the occurrence of musculoskeletal disorders, such as thoracic hyperkyphosis (THK) or lumbar hypolordosis (LHL), is a result of demographic changes. Exercise therapy is an effective approach that can reduce related disabilities and costs. To ensure successful therapy, an individualized exercise program adapted to the severity of the disorder is expedient. Nevertheless, appropriate classification systems are scarce. This project aimed to develop and evaluate a severity classification focused on exercise therapy for patients with THK or LHL. A multilevel severity classification was developed and evaluated by means of an online survey. Reference limits of spinal shape angles were established by data from video rasterstereography of 201 healthy participants. A mean kyphosis angle of 50.03° and an average lordosis angle of 40.72° were calculated as healthy references. The strength of the multilevel classification consisting of the combination of subjective pain and objective spinal shape factors was confirmed by the survey (70% agreement). In particular, the included pain parameters were considered relevant by 78% of the experts. Even though the results of the survey provide important evidence for further analyses and optimization options of the classification system, the current version is still acceptable as therapeutic support.

Mechanical complications and patient-reported outcome measures associated with high pelvic incidence and persistent pelvic retroversion: the Roussouly "false type 2" profile.

OBJECTIVE: The objective of this paper was to report mechanical complications and patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) patients with a Roussouly "false type 2" (FT2) profile. METHODS: ASD patients treated from 2004 to 2014 at a single center were identified. Inclusion criteria were pelvic incidence ≥ 60° and a minimum 2-year follow-up. FT2 was defined as a high postoperative pelvic tilt (PT), as defined by the Global Alignment and Proportion target, and thoracic kyphosis < 30°. Mechanical complications, defined as proximal junctional kyphosis (PJK) and/or instrumentation failure, were determined and compared. Scoliosis Research Society-22r (SRS-22r) scores were compared between groups. RESULTS: Ninety-five patients (normal PT [NPT] group 49, FT2 group 46) who met the inclusion criteria were identified and studied. Most surgeries were revisions (NPT group 30 [61%], FT2 group 30 [65%]), and most were performed via a posterior-only approach (86%) (mean ± SD 9.6 ± 5 levels). Proximal junctional angles increased after surgery in both groups, without differences between groups. Neither rates of radiographic PJK (p = 0.10), revision for PJK (p = 0.45), nor revision for pseudarthrosis (p = 0.66) were different between groups. There were no differences between groups for SRS-22r domain scores or subscores. CONCLUSIONS: In this single-center experience, patients with high pelvic incidence fixed with persistent lumbopelvic parameter mismatch and engaged compensatory mechanisms (Roussouly FT2) had mechanical complications and PROMs not different from those with normalized alignment parameters. Compensatory PT may be acceptable in some cases of ASD surgery.

Surgical treatment of double major adolescent idiopathic scoliosis can lead to excessive lumbar lordosis in the instrumented segments.

PURPOSE: The purpose of this study was to characterize the sagittal spine in AIS patients with double major curves fused into the lumbar spine to determine the effects of posterior spinal fusion and instrumentation (PSFI) on global and segmental lumbar sagittal parameters. METHODS: A consecutive series of AIS patients undergoing a PSFI from 2012 to 2017 having Lenke 3, 4 or 6 curves were analyzed. Sagittal parameters included pelvic incidence (PI), lumbar lordosis (LL), and segmental lordosis were measured. The difference in segmental lumbar lordosis between the preoperative, 6-week, and 2-year radiographs was analyzed and correlated to outcomes using SRS-30 patient questionnaires. RESULTS: Seventy-seven patients had improvement in their coronal Cobb from 67.3 ± 11.8° to 25.43 ± 10.7° (66.4%) at 2 years. There was no change in thoracic kyphosis (23.0 ± 13.4° to 20.3 ± 7.8°) and pelvic incidence (49.9 ± 13.4° to 51.1 ± 15.7°) from preoperative to 2 years (p > 0.05) while lumbar lordosis increased from 57.6 ± 12.4° to 61.4° ± 12.3° (p = 0.002). Segmental lumbar analysis showed increased (+) lordosis at each instrumented level when comparing the preoperative and 2-year films for: T12-L1 (+ 3.24°, p < 0.001), L1-L2 (+ 5.70°, p < 0.001), and L2-L3 (+ 1.70°, p < 0.001). Loss (-) of lordosis was noted at every level below the LIV: L3-L4 (- 1.70°, p < 0.001), L4-L5 (- 3.52°, p < 0.001), L5-S1 (- 1.98°, p = 0.02). Preoperative LL of L4-S1 comprised 70 ± 16% of the global LL compared to 56 ± 12%, at 2 years (p < 0.001). Changes in sagittal measurements did not correlate with SRS outcome scores at two-year follow-up. CONCLUSION: When performing PSFI for double major scoliosis, global SVA was maintained at 2 years, however, overall lumbar lordosis increased due to an increased lordosis in the instrumented segments and a smaller decrease in lordosis below the LIV. Surgeons should be wary of the tendency to create instrumented lumbar lordosis with a compensatory loss of lordosis below LIV which may be a set-up for poor long-term outcomes in adulthood.

Radiographic patterns and characteristics of sagittal profiles in normal spinopelvic curvatures: An explicit depiction of the distribution of lumbar vertebral bodies and discs.

The current study aimed to investigate the sagittal morphology of the spinopelvic complex and the components of the lumbar spine in the normal population. In total, 132 adult volunteers were retrospectively evaluated and divided into four groups according to the Roussouly classification. Statistical analysis of radiological parameters, including lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), PI-LL, LL-TK, lumbar vertebral lordosis from L1 to L5 (L1L-L5L), the intervertebral angle from L1-L2 to L5-S1 (IVA1-2-IVA5-1), segmental lordosis from L1 to L5 (S1L-S5L), the proportion of L1-L5 (L1%-L5%), the proportion of the intervertebral angle from L1-L2 to L5-S1 (IVA1-2%-IVA5-1%), and proportion of segmental lordosis from L1 to L5 (S1L%-S5L%), was performed. Based on the classification, type II (n = 46) was the most common, followed by type I (n = 39), type III (n = 36), and type IV (n = 11). The quantitative values of the sagittal parameters of the four groups were obtained. Results showed a significant difference in terms of LL, PI, SS, and LL-TK. Further, L1%, L2%, L3%, IVA1-2%, IVA2-3%, S1L%, S2L%, and S3L% had an increasing trend. PI was positively correlated with LL, S1L, S2L, S3L, S4L, S1L%, and S2L%, but not with S5L%. In conclusion, pelvic parameters had a significant effect on lumbar curvature and lordosis distribution. Further, the abovementioned results were beneficial for individual surgical decision-making regarding targeted intervertebral angle, screw-insertion dimension, and rod contouring.

Surgeon and SterEOS agreement of spinal sagittal plane parameters in patients with adolescent idiopathic scoliosis.

PURPOSE: To compare agreement between surgeons and sterEOS sagittal plane measurements. METHODS: EOS radiographs of 74 patients with adolescent idiopathic scoliosis were reviewed. The measurements were generated by two surgeons and compared to sterEOS. Intraclass correlations (ICC) were calculated. Agreement was also analyzed for the following subgroups: Cobb angle < 70° vs ≥ 70°, lumbar modifier A vs B/C, and BMI of < 24.5 kg/m2 vs ≥ 24.5 kg/m2. Agreement was poor if the ICC was < 0.5, moderate if 0.5-0.75, good if 0.75-0.9, and excellent if > 0.9. Paired t tests were performed to compare the surgeon's and sterEOS means. RESULTS: For the surgeons, agreement was good (0.75-0.89) except for pelvic tilt (PT) and sacral slope (SS), which were excellent (0.91-0.92). Agreement between the surgeons and sterEOS were good (0.78-0.9) except PT and SS, which were excellent (0.91-0.93). Agreement was negatively affected for T4-T12 kyphosis, PI, and SS in the ≥ 70°group, LL when BMI was ≥ 24.5 kg/m2, and LL, PI, and SS in the lumbar modifier B/C group. The ICCs overlapped with the 95% confidence intervals (95% CI). Paired t-test showed a significant difference for T4-T12 kyphosis (p < 0.001). This was also true in the < 70° group (p < 0.001), the ≥ 70° group (p = 0.04), and the BMI < 24.5 kg/m2 group. PT was significantly different for the ≥ 70° group. CONCLUSIONS: There was good to excellent agreement between the surgeons and surgeons and sterEOS. Some variables may affect agreement. The surgeons overestimated T4-T12 kyphosis.