Posterior vertebral column resection: Exploring practical uses in clinical settings.

Background: The purpose of this study was to present our experience in patients who had been treated with posterior vertebral column resection (PVCR) for various spinal deformities. Methods: Thirty-seven patients who performed PVCR between 2015 and 2018 were evaluated retrospectively. The mean follow-up period was 24 months (range: 12-50 months). The demographic data of the patients, mean blood loss, amount of blood replacement, duration of operation, intensive care and hospitalization period, PVCR level, instrumentation level, amount of preoperative curvature, amount of postoperative curvature improvement, preoperative and postoperative neurological status, and complications were examined. Angular measurements were performed on X-ray. Results: The mean age of the patients was 37.5 years (range: 3-80 years). PVCR was applied to patients due to different pathologies (congenital, tumor metastasis, posttraumatic kyphosis, revision scoliosis, and infection). The mean operation time was 445.5 min (260-720) with an average blood loss of 1903 ml (400-7000 ml). It was observed that the average local kyphosis angle decreased from 67.65° to 7.42° in 26 patients who were operated for advanced deformity (P < 0.001). When these values were compared in all 34 patients, the preoperative angle value decreased from 55.1° to 3.5° (P < 0.001) and decreased from 70° to 0° in 13 congenital kyphosis patients. Conclusion: PVCR is an effective method for correcting severe spinal deformities and can be used to correct curvature in different patient groups. Level of Evidence: Level 3.

Ultrasound-guided caudal cervical articular process arthrocentesis is accurate in live horses with and without arthropathy.

BACKGROUND: Cervical articular process joint (CAPJ) therapy is advocated for horses with neck disorders. Several ultrasound-guided CAPJ techniques have been described in cadaver studies with 72%-89% intra-articular injection accuracy; however, the CAPJ injection accuracy in clinical equine practice has not been extensively reported. OBJECTIVES: To describe a modified cranial approach for ultrasound-guided caudal CAPJ injections, to investigate the accuracy of this CAPJ injection technique in live horses, and to assess the effect of CAPJ injection location, laterality, operator, and radiographic CAPJ enlargement on injection accuracy. STUDY DESIGN: Retrospective case study. METHODS: Medical records of adult horses in which ultrasound-guided caudal (C4-T1) CAPJ injections were performed using a modified cranial approach between November 2006 and December 2020 were reviewed. Radiographic images of caudal cervical vertebrae were assessed by a blinded radiologist and the degree of CAPJ enlargement was graded using a previously described grading system (Rgrade 1-5b). Ultrasound-guided caudal CAPJ injection accuracy was determined by synovial fluid retrieval during an individual CAPJ injection. Statistical analysis was performed using mixed-effects multivariable logistic model to evaluate the association of CAPJ injection accuracy and the CAPJ injection location, Rgrade, laterality (right, left), and operator. RESULTS: The study included 149 horses with 177 hospital admissions. Synovial fluid was obtained from 586/658 (89.1%) caudal CAPJs using modified cranial ultrasound-guided approach for CAPJ injections. C6-C7 CAPJ injections had 7-fold higher likelihood (OR = 6.78, 95% CI: 1.67-27.52; p = 0.007) of synovial fluid retrieval compared with C4-C5 CAPJ injections. Operator, CAPJ injection side (left, right), and degree of radiographic CAPJ enlargement did not have significant effects on the success of synovial fluid retrieval from ultrasound-guided caudal CAPJ injections. MAIN LIMITATIONS: Retrospective study design. CONCLUSIONS: Intra-articular ultrasound-guided caudal CAPJ injections using a modified cranial approach can be performed accurately in live horses with and without CAPJ arthropathy.

Vertebral Column Pathology Diagnosis Using Ensemble Strategies Based on Supervised Machine Learning Techniques.

One expanding area of bioinformatics is medical diagnosis through the categorization of biomedical characteristics. Automatic medical strategies to boost the diagnostic through machine learning (ML) methods are challenging. They require a formal examination of their performance to identify the best conditions that enhance the ML method. This work proposes variants of the Voting and Stacking (VC and SC) ensemble strategies based on diverse auto-tuning supervised machine learning techniques to increase the efficacy of traditional baseline classifiers for the automatic diagnosis of vertebral column orthopedic illnesses. The ensemble strategies are created by first combining a complete set of auto-tuned baseline classifiers based on different processes, such as geometric, probabilistic, logic, and optimization. Next, the three most promising classifiers are selected among k-Nearest Neighbors (kNN), Naïve Bayes (NB), Logistic Regression (LR), Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Support Vector Machine (SVM), Artificial Neural Networks (ANN), and Decision Tree (DT). The grid-search K-Fold cross-validation strategy is applied to auto-tune the baseline classifier hyperparameters. The performances of the proposed ensemble strategies are independently compared with the auto-tuned baseline classifiers. A concise analysis evaluates accuracy, precision, recall, F1-score, and ROC-ACU metrics. The analysis also examines the misclassified disease elements to find the most and least reliable classifiers for this specific medical problem. The results show that the VC ensemble strategy provides an improvement comparable to that of the best baseline classifier (the kNN). Meanwhile, when all baseline classifiers are included in the SC ensemble, this strategy surpasses 95% in all the evaluated metrics, standing out as the most suitable option for classifying vertebral column diseases.

The Hox code responsible for the patterning of the anterior vertebrae in zebrafish.

The vertebral column is a characteristic structure of vertebrates. Genetic studies in mice have shown that Hox-mediated patterning plays a key role in specifying discrete anatomical regions of the vertebral column. Expression pattern analyses in several vertebrate embryos have provided correlative evidence that the anterior boundaries of Hox expression coincide with distinct anatomical vertebrae. However, because functional analyses have been limited to mice, it remains unclear which Hox genes actually function in vertebral patterning in other vertebrates. In this study, various zebrafish Hox mutants were generated for loss-of-function phenotypic analysis to functionally decipher the Hox code responsible for the zebrafish anterior vertebrae between the occipital and thoracic vertebrae. We found that Hox genes in HoxB- and HoxC-related clusters participate in regulating the morphology of the zebrafish anterior vertebrae. In addition, medaka hoxc6a was found to be responsible for anterior vertebral identity, as in zebrafish. Based on phenotypic similarities with Hoxc6 knockout mice, our results suggest that the Hox patterning system, including at least Hoxc6, may have been functionally established in the vertebral patterning of the common ancestor of ray-finned and lobe-finned fishes.

Accuracy and safety of freehand vs. end-on fluoroscopic guided drill-hole placement in canine cadaveric thoracic, lumbar and sacral vertebrae.

Objective: To develop and evaluate the safety and accuracy of an open, end-on fluoroscopic guided (EOFG) drill hole position technique in canine cadaveric spinal surgery, in comparison to a traditional free-hand (FH) drilling technique. Study design: Cadaveric comparison study. Animals: Canine cadaveric vertebral columns (n = 4). Methods: Computed tomography (CT) scans were performed for in-silico planning. Ideal implant purchase depth and angulations were determined from previously published data. Plans for end-on fluoroscopic guided drill holes included angled reconstructions in thick slab mode to mimic fluoroscopic images. Following surgical preparation of T8 to S2, holes were drilled by one of two experienced surgeons randomized evenly by operated side, surgeon, and technique. C-arm fluoroscopy was utilized for the end-on technique. CT was repeated after the procedures. Safety was determined categorically using a modified Zdichavsky classification and "optimal" placement was compared between techniques. Continuous data for drill-hole accuracy was calculated as angle and depth deviations from the planned trajectories. Data sets were analyzed at both univariable and multivariable levels with logistic regression analysis. Results: Drill hole safety was categorized as optimal (modified Zdichavsky classification 1) in 51/60 (85%) of drill holes using EOFG and 33/60 (55%) using FH (P < 0.001) techniques. There were no "unsafe" holes (modified Zdichavsky classification 3a). Optimal drill hole placement was significantly associated with the EOFG technique and use of the largest cadaver, and was significantly less likely within the thoracic region. Mean angle and depth deviations were significantly lower with the EOFG technique. Angle deviations were significantly lower for EOFG in the lumbar region, whereas bone purchase deviations were significantly lower for EOFG in both the thoracic and lumbar regions. The mean time taken to drill the hole was significantly longer for the EOFG technique. Conclusion: Optimal drill hole placement was significantly more likely with the EOFG technique and improved the accuracy of bone purchase in the thoracic region. Clinical significance: The EOFG technique shows promise for translation into a clinically setting, potentially improving implant purchase and therefore stabilizing construct strength, whilst potentially reducing the likelihood of neurovascular injury and need for surgical revision.

Severe (>100 Degrees) Thoracic Adolescent Idiopathic Scoliosis - A Comparison of Surgical Approaches.

STUDY DESIGN: Retrospective. OBJECTIVE: Severe curves >100° in adolescent idiopathic scoliosis (AIS) are rare and require careful operative planning. The aim of this study was to assess baseline, perioperative, and 2-year differences between anterior release with posterior instrumentation (AP), posterior instrumentation with posterior column osteotomies (P), and posterior instrumentation with 3-column vertebral osteotomies (VCR). METHODS: Two scoliosis datasets were queried for primary cases of severe thoracic AIS (≥100°) with 2-year follow-up. Pre- and 2-year postoperative radiographic measures (2D and estimated 3D kyphosis), clinical measurements, and SRS-22 outcomes were compared between three approaches. RESULTS: Sixty-one patients were included: 16 AP (26%), 38 P (62%), 7 VCR (11%). Average age was 14.4 ± 2.0 years; 75.4% were female. Preoperative thoracic curve magnitude (AP: 112°, P: 115°, VCR: 126°, P = 0.09) and T5-T12 kyphosis (AP: 38°, P: 59°, VCR: 70°, P = 0.057) were similar between groups. Estimated 3D kyphosis was less in AP vs P (-12° vs 4°, P = 0.016). Main thoracic curves corrected to 36° in AP vs 49° and 48° for P and VCR, respectively (P = 0.02). Change in estimated 3D kyphosis was greater in AP vs P and VCR (34° vs 13°, P = 0.009; 34° vs 7°, P = 0.046). One incomplete spinal cord injury had residual deficits (P; 1/61, 1.6%). All SRS-22 domains improved postoperatively. CONCLUSION: All approaches obtained satisfactory coronal and sagittal correction, but AP had smaller residual coronal deformity and greater kyphosis restoration than the other approaches. This information may help inform the decision of whether to include an anterior release for large thoracic AIS curves.

Posterior-Only T11 Vertebral Column Resection for Pediatric Congenital Kyphosis Surgical Correction.

Background: Congenital kyphosis is a spinal deformity that arises from the inadequate anterior development or segmentation of the vertebrae in the sagittal plane during the initial embryonic stage. Consequently, this condition triggers atypical spinal growth, leading to the manifestation of deformity. Concurrently, other congenital abnormalities like renal or cardiac defects within the gastrointestinal tract may co-occur with spinal deformities due to their shared formation timeline. In light of the specific characteristics of the deformity, the age range of the patient, deformity sizes, and neurological conditions, surgical intervention emerges as the optimal course of action for such cases. The selection of the appropriate surgical approach is contingent upon the specific characteristics of the anomaly. Case Presentation: This investigation illustrates the utilization of a surgical posterior-only strategy for correcting pediatric congenital kyphoscoliosis through the implementation of a vertebral column resection method along with spine reconstruction employing a mesh cage. The individual in question, a 16-year-old female, exhibited symptoms such as a progressive rib hump, shoulder asymmetry, and back discomfort. Non-invasive interventions like bracing proved ineffective, leading to the progression of the spinal curvature. After the surgical procedure, diagnostic imaging displayed a marked enhancement across all three spatial dimensions. After a postoperative physical assessment, it was noted that the patient experienced significant enhancements in shoulder alignment and rib hump prominence, with no discernible neurological or other adverse effects. Conclusions: Surgical intervention is considered the optimal approach for addressing such congenital anomalies. Typically, timely surgical intervention leads to favorable results and has the potential to halt the advancement of deformity and curvature enlargement.

The Vertebral morphology in dolphins (Delphinidae): A 3D approach

For almost 90 years, the cetacean vertebral column has puzzled scientists. This is the first 3D geometric morphometric study on the vertebral column of such a numerous group of small odontocetes (24 species). It uses a functional subdivision of the cetacean vertebral column and three landmark configurations to describe and compare vertebral morphology in Delphinidae, relating particular morphologies with the biomechanical requirements of each species. To this end, I assess the effect of size, and that of size and subfamily on vertebral morphology. I also analyzed the statistical differences in shape between species. Phylomorphospaces were created to assess similarities or differences in shape between closely related species with similar/dissimilar habitats. The allometric effect was low in all regions, and there were subfamily-specific allometric effects. Differences between species were greater in the mid-column but this was only partially confirmed statistically, presumably due to low n for some species. The percentage of variance explained by the first two PCs was higher than 58% in all regions, with the torso and the tail stock showing the greatest percentages of explained variance. The results suggest that the common ancestor of dolphins would have be a non-fast-swimming oceanic species. Coastal habitats seem to have evolved secondarily by means of a reduction in vertebral count, and vertebral morphology associated with greater flexibility (i. e., longer centra, smaller faces). On the contrary, an increased total count and disk-shaped vertebrae were observed to varying degrees in non-coastal species, with the most extreme modifications being found in species with particular habitat specializations. My results support the hypothesis that diversification in vertebral morphology in association to particular habitats was a key factor in delphinid explosive radiation, and provides descriptive basis for analysis of the phylogenetic constrains in vertebral morphology needed to elucidate dolphin diversification and the factors behind it.

The Late Cretaceous eutherian Zalambdalestes reveals unique axis and complex evolution of the mammalian neck.

The typical mammalian neck consisting of seven cervical vertebrae (C1-C7) was established by the Late Permian in the cynodont forerunners of modern mammals. This structure is precisely adapted to facilitate movements of the head during feeding, locomotion, predator evasion, and social interactions. Eutheria, the clade including crown placentals, has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic. Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations. A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae (C2-C7) revealing a highly modified axis (C2). The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals, muscle reconstruction, geometric morphometrics and virtual range of motion analysis. We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species (monotremes, marsupials, and placentals) using three-dimensional landmark analysis. The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals. Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size. These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.

Posterior Corrective Surgery for Type II Congenital Kyphosis: SRS-Schwab Grade 4 Osteotomy or Vertebral Column Resection?

OBJECTIVE: Surgical decision-making for congenital kyphosis (CK) with failure of anterior segmentation (type II) has been contradictory regarding the trade-off between the pursuit of correction rate and the inherent risk of the osteotomy procedure. This study was designed to compare the clinical and radiographic measurement in type II CK underwent SRS-Schwab Grade 4 osteotomy and vertebral column resection (VCR), the most-adapted osteotomy techniques for CK, and to propose the strategy to select between the two procedures. METHODS: This retrospective observational comparative study evaluated surgical outcomes in type II CK patients underwent VCR or SRS-Schwab Grade 4 osteotomy at our institution between January 2015 and January 2020. Patients operated with VCR and SRS-Schwab Grade 4 osteotomy were allocated to Group 1 and Group 2 respectively. Radiographic parameters and SRS-22 quality of life metrics were assessed at pre-operation, post-operation, and during follow-up visits for both groups, allowing for a comprehensive comparison of surgical outcomes. RESULTS: Thirty-one patients (19 patients in Group 1 and 12 patients in Group 2) aged 16.3 ± 10.4 years were recruited. Correction of segmental kyphosis was similar between groups (51.1 ± 17.6° in Group 1 and 48.4 ± 19.8° in Group 2, p = 0.694). Group 1 had significantly longer operation time (365.9 ± 81.2 vs 221.4 ± 78.9, p < 0.001) and more estimated blood loss (975.2 ± 275.8 ml vs 725.9 ± 204.3 mL, p = 0.011). Alert event of intraoperative sensory and motor evoked potential (SEP and MEP) monitoring was observed in 1 patient of Group 2. Both groups had 1 transient post operative neurological deficit respectively. CONCLUSION: SRS-Schwab Grade 4 osteotomy was suitable for kyphotic mass when its apex is the upper unsegmented vertebrae or the neighboring disc, or when the apical vertebrae with an anterior/posterior (A/P) height ratio of vertebral body higher than 1/3. VCR is suitable when the apex is located within the unsegmented mass with its A/P height ratio lower than 1/3. Proper selection of VCR and SRS-Schwab Grade 4 osteotomy according to our strategy, could provide satisfying radiographic and clinical outcomes in type II CK patients during a minimum of 2 years follow-up. Patients undergoing VCR procedure might have longer operation time, more blood loss and higher incidence of peri- and post-operative complications.

Clinical and radiologic outcomes of posterior column extension, pedicle subtraction, and vertebral column resection osteotomies in adult chin on chest deformity: A systematic review.

Background: Chin-on-chest deformity is a rare and severely disabling condition characterized by kyphotic deformity in the cervicothoracic spine. To treat this deformity, various osteotomy techniques were described. Methods: A comprehensive literature search of biomedical databases including MEDLINE (via PubMed), Scopus (via Elsevier), Embase (via Elsevier), and Cochrane Library in English from 1/1/1990 to 3/31/2022 was conducted using a combination of text and Medical Subject Headings (MeSH). Results: The final analysis included 16 studies. All the studies were assigned a level of evidence of four. Except for two articles, all of the articles were non-comparative studies. A total of 288 patients were included in this review. Of the 288 patients, 107 underwent posterior column extension osteotomy (PCEO), 108 underwent pedicle subtraction osteotomy (PSO), and 33 underwent vertebral column resection osteotomy (VCRO). The most common osteotomy level in fifteen of the studies was C7/T1. The studies included in this review described several techniques for cervical sagittal balance correction. The range of preoperative and postoperative visual analogue scale (VAS) scores was 5.5-8.6 to 1.7-4.91, respectively. The range of preoperative and postoperative neck disability index (NDI) was 34.2-65.4 to 22.1-51.3, respectively. The most common complications were upper extremity paresthesia and hand numbness through the C8 dermatome distribution. Conclusions: Corrective osteotomies provide satisfactory results in patients with chin-on-chest deformity; however, the quality of the included studies limits the evidence.

Surgical technique: Posterior retropleural thoracotomy for resection of a T10 dumbbell schwannoma.

Background: Myelopathy and nerve root dysfunction resulting from the imperceptible growth of intraspinal schwannomas have been well documented.[1] Thoracic spine schwannomas, in particular, have exceptional growth potential due to the presence of the posterior mediastinum and retropleural spaces accommodating insidious and often subclinical tumor expansion.[5] Extraspinal extension of these lesions, however, poses a distinct challenge for surgeons.[3,4]. Case Description: Here, we provide a two-dimensional intraoperative video demonstrating the technical nuances concerning maximally safe resection of a partially cystic thoracic dumbbell schwannoma having extraspinal extension with associated bony remodeling of the T10 vertebral body and neural foramen in a middle-aged male. A posterolateral approach with T8-T12 fusion, retropleural thoracotomy, facetectomies, and pediculectomies allowed for gross total resection. No intraoperative or postoperative complications were observed, and the parietal pleura was kept intact throughout the surgery. In addition, the patient continued to have improved symptoms and was ambulatory at 6-month follow-up. Conclusion: Gross total resection of a partially cystic thoracic dumbbell schwannoma was achieved without complications. Our use of a preoperative three-dimensional reconstruction for surgical planning,[2] intraoperative ultrasound,[6] and a durable instrumentation construct were essential for a successful outcome. Moreover, great care was taken to avoid violating the tumor-parietal pleura plane, which would have resulted in postoperative respiratory complications.

Complications and outcomes after three-column osteotomy: a 5-year follow-up.

BACKGROUND: Three-column spinal osteotomies (3-CO) are powerful techniques used to correct spinal deformity. These surgeries are associated with an elevated risk of complications. While outcomes have been reported in the literature with 2 years follow-up, longer-term outcomes of three-column osteotomies remain understudied. OBJECTIVES: This study aims to examine patient reported outcomes and complications for three-column osteotomies at 5 years. STUDY DESIGN: Retrospective review of a prospectively collected spinal deformity cases database. PATIENT SAMPLE: All consecutive adult patients at a single spine surgery center treated with either a pedicle subtraction osteotomy (PSO) or vertebral column resection (VCR) for spinal deformity, and with a minimum 5-year follow-up were included. OUTCOME MEASURES: Visual-analog scale (VAS) for back pain score (0 to 10), Oswestry Disability Index (ODI) score (0 to 100), number of complications, revision rate, sagittal balance, lumbar lordosis at preoperative and at 5-year visit. METHODS: Data was extracted from a prospectively collected spinal deformity surgery database continuously updated since 2002 with data from operative reports, patients' medical visit notes and patients' self-reported VAS and ODI questionnaires completed at each office visit. Radiographic measurements were performed on standing full-length spine radiographs taken at pre-op and 5-year visits. Descriptive statistics, comparison of means and proportions among groups, and a logistic regression analysis were conducted using the statistical software package SPSS version 28. Statistical significance was set at p<.05. RESULTS: Of 127 consecutive adult patients with minimum of 5-year follow-up undergoing a 3-CO posterior spinal surgery for spinal deformity were identified and included in the study, 79 (62%) were treated with PSO, and 48 (38%) with VCR. Both PSO and VCR groups demonstrated significant improvements in VAS (PSO pre-op: 6.7, 5-year: 4.6, p<.001; VCR pre-op: 7.1, 5-year: 5.2, p<.001), and ODI (PSO pre-op: 52.9, 5-year: 45.4, p<.001; VCR pre-op: 57.5, 5-year 43.0, p<.001) that were maintained at 5 years. Major and minor complications occurring within 5 years were not statistically different between the PSO and VCR groups (major: 59.5% vs 56.3%, p=.85; minor: 45.6% vs 37.5%, p=.46). The rate of revision surgery within 5 years was 39.4% overall. Of the fifty patients requiring revision, 37.5% were for nonunion, 27.1% instrumentation failure, 14.6% proximal junctional kyphosis (PJK), 12.5% vertebral fracture, 6.3% motor weakness, and 2.1% infection. Improvements in lumbar lordosis were maintained at 5 years in both the PSO (29.9° vs 47.2°, p<.001) and VCR (34.6° vs 48.5°, p<.001) groups while sagittal balance maintained significant improvement in the VCR group (9.5 cm vs 6.3 cm, p=.008) but not the PSO (11.4 cm vs 9.3 cm, p=.065). CONCLUSION: Patients undergoing three-column osteotomies had a major complication rate of 57.5% and a minor complication rate of 42.5% after 5 years. Improvements in lumbar lordosis were maintained at 5-year follow-up, but sagittal balance was only maintained in the VCR group. Despite these radiographic findings, both VCR and PSO groups maintained significant clinical improvements in both VAS and ODI scores at 5-year follow up.

A critical event frequent lead to reversible spinal cord injury during vertebral column resection surgery.

OBJECTIVE: To report a "critical phase" (between osteotomy completion and correction beginning) that will frequently lead to the reversible intraoperative neurophysiological monitoring (IOM) change during posterior vertebral column resection (PVCR) surgery. METHODS: The study sample consisted of 120 patients with severe spine deformity who underwent PVCR and deformity correction surgeries. Those patients were recruited consecutively from 2010 to 2018 January in our spine center. The detailed IOM data (the amplitude of MEP & SEP) and its corresponding surgical points were collected prospectively. Early and long-term postoperative neurologic outcomes were assessed for the following functions: motor, sensory, and pain at immediate postoperative and 1-year post-operation in this cases series. RESULTS: A total of 105 (105/120) patients presented varying degrees of IOM reduction in the critical phase; the mean IOM amplitude retention vs rescue rate was 27% ± 11.2 versus 58% ± 16.9, P < 0.01 (MEP) & 34% ± 8.3 versus 66% ± 12.4 P < 0.01 (SEP). Patients with postoperative spinal deficits often had a significantly longer IOM-alerting duration than the patients without (p < 0.01, Mann-Whitney U-test), and IOM-alerting duration greater than 39.5 min was identified as an independent predictor of the risk of postoperative spinal deficits. CONCLUSIONS: The reversible IOM events probably often appear in the critical phase during PVCR surgery. The new postoperative spinal deficits are possible for patients without satisfied IOM recovery or alerting duration greater than 39.5 min. Timely and suitable surgical interventions are useful for rescuing the IOM alerts.

The influence of the land-to-sea macroevolutionary transition on vertebral column disparification in Pinnipedia.

The repeated returns of vertebrates to the marine ecosystems since the Triassic serve as an evolutionary model to understand macroevolutionary change. Here we investigate the effects of the land-to-sea transition on disparity and constraint of the vertebral column in aquatic carnivorans (Carnivora; Pinnipedia) to assess how their functional diversity and evolutionary innovations influenced major radiations of crown pinnipeds. We use three-dimensional geometric morphometrics and multivariate analysis for high-dimensional data under a phylogenetic framework to quantify vertebral size and shape in living and extinct pinnipeds. Our analysis demonstrates an important shift in vertebral column evolution by 10-12 million years ago, from an unconstrained to a constrained evolutionary scenario, a point of time that coincides with the major radiation of crown pinnipeds. Moreover, we also demonstrate that the axial skeleton of phocids and otariids followed a different path of morphological evolution that was probably driven by their specialized locomotor strategies. Despite this, we found a significant effect of habitat preference (coastal versus pelagic) on vertebral morphology of crown taxa regardless of the family they belong. In summary, our analysis provides insights into how the land-to-sea transition influenced the complex evolutionary history of pinniped vertebral morphology.

International survey of equine orthopaedic specialists reveals diverse treatment strategies for horses with overriding spinous processes.

BACKGROUND: Overriding spinous processes, also known as 'kissing spines', are one of the most common causes of back pain in horses. The aim of this study was to investigate which options for diagnosis and treatment are preferred by equine orthopaedic specialists and assess which techniques are used for local injection. METHODS: An online survey was distributed among members of the European/American College of Veterinary Surgeons, the European/American College of Veterinary Sports Medicine and Rehabilitation, the International Society of Equine Locomotor Pathology and nationally recognised advanced equine orthopaedic practitioners. RESULTS: The survey was completed by 353 respondents. The injection techniques most commonly used involve placing two needles abaxial to the interspinous space (42%) under ultrasonographic guidance (32%) or one needle in the midline (35%) between two spinous processes. The most popular combination for overriding dorsal spinous process therapy was local injection (26.7%) combined with controlled exercise (25.5%). Manual therapy was considered by 42% of European and 25% of American specialists (p = 0.01). Surgical intervention as a first-line treatment was recommended mainly by specialists working in the United States, the UK or Ireland (p = 0.001). Overall, most equine orthopaedic veterinarians (71%; n = 201) preferred conservative management and recommended surgery only for horses that did not respond to conservative therapy. LIMITATIONS: Respondents' personal bias may have skewed the findings. CONCLUSIONS: Despite a growing body of evidence, the therapeutic approach to 'kissing spines' in horses is influenced by professional specialisation and regional preferences. Variations in injection techniques and differing criteria for surgical intervention warrant further investigation.

Epichordal vertebral column formation in Xenopus laevis.

Although Xenopus Laevis is the most widely used model amphibian, skeletal development of its vertebral column has not been well illustrated so far. The mode of vertebral column development in anurans has been classified into two modes: perichordal and epichordal. Xenopus vertebral column formation is believed to follow the epichordal mode, but this aspect has been underemphasized, and illustrative examples are currently unavailable to the scientific community. This study documents the entire process of vertebral column formation in X. laevis, from the initial neural arch formation to the completion of metamorphosis. These images reveal that the neural arch arises from the dorsal lamina and lateral pedicle primordia, with no strict adherence to an anteroposterior sequence. Unlike other species, Xenopus centrum primordia exclusively form at the expanded ventral margins of neural arches, rather than from the cartilaginous layer surrounding the notochord. These paired centrum primordia then fuse at the ventral midline, dorsal to the notochord, and subsequently the notochord degenerates. This mode of centrum formation differs from the traditional epichordal mode, indicating that Xenopus might have lost the ability to form a cartilaginous layer around the notochord. Instead, the neural arch's ventral margin appears to have evolved to incorporate centrum precursor cells at its base, thereby forming a centrum-like structure compensating for the absence of a true centrum. It is widely accepted that postsacral vertebrae lack centra, only possessing neural arches, and eventually fuse with the hypochord to form the urostyle. However, we have shown that the paired ventral ends of the postsacral vertebrae also fuse at the midline to form a centrum-like structure. This process might extend to the trunk region during centrum formation. In addition to these findings, we offer evolutionary insights into the reasons why Xenopus retains centrum primordia at the base of neural arches.

Functional diversity of snake locomotor behaviors: A review of the biological literature for bioinspiration.

Organismal solutions to natural challenges can spark creative engineering applications. However, most engineers are not experts in organismal biology, creating a potential barrier to maximally effective bioinspired design. In this review, we aim to reduce that barrier with respect to a group of organisms that hold particular promise for a variety of applications: snakes. Representing >10% of tetrapod vertebrates, snakes inhabit nearly every imaginable terrestrial environment, moving with ease under many conditions that would thwart other animals. To do so, they employ over a dozen different types of locomotion (perhaps well over). Lacking limbs, they have evolved axial musculoskeletal features that enable their vast functional diversity, which can vary across species. Different species also have various skin features that provide numerous functional benefits, including frictional anisotropy or isotropy (as their locomotor habits demand), waterproofing, dirt shedding, antimicrobial properties, structural colors, and wear resistance. Snakes clearly have much to offer to the fields of robotics and materials science. We aim for this review to increase knowledge of snake functional diversity by facilitating access to the relevant literature.

Gait analysis, trunk movements, and electromyographic patterns after minimally invasive spine surgery for lumbar instability: An observational prospective study.

Objective: The aim of the present study was to investigate trunk kinematics and spine muscle activation during walking after minimally invasive surgery in patients with L4-L5 degenerative spondylolisthesis suffering from lumbar instability (LI). Methods: Eleven patients suffering from LI and 13 healthy controls (HC) were enrolled. Trunk kinematics and spine muscle activation patterns during walking were collected. Maximal trunk ranges of motion were also recorded from standing position. Assessments were performed pre-operatively (T0), 1 month (T1) and 3 months (T2) after MIS. Results: We found significant improvement in spine muscle activation during walking at T2 compared to T0, mainly involving right/left symmetry at the operated level (L4-L5) and up-down synchronization from L3 to S1. Significant improvements in trunk rotation nearing to the HC group during walking were also found at T2 after surgery, though no changes were observed in the maximal range of motion of the trunk during standing. Furthermore, trunk rotation improvement correlated with a lower grade of residual disability. Conclusions: Our findings indicate that trunk rotation improves after surgery, and impaired aspects of spine muscle activation can be improved with surgery. These biomechanical parameters could represent novel tools for monitoring the effect of surgery in LI and preventing impaired spine mobility and muscle activation.

The complex treatment paradigms for concomitant tethered cord and scoliosis: illustrative case.

BACKGROUND: Scoliosis associated with tethered cord syndrome is one of the most challenging spinal deformities to manage. Multiple surgical approaches have been developed, including traditional staged and concomitant procedures, spine-shortening osteotomies, and individual vertebral column resections. OBSERVATIONS: A 10-year-old female presented with congenital kyphoscoliosis with worsening curve progression, tethered spinal cord, and a history of enuresis. The scoliosis had progressed to a 26° coronal curve and 55° thoracolumbar kyphosis. Preoperative magnetic resonance imaging of the spine revealed a tethered cord between the levels of L3-4 and a large kyphotic deformity at L1. The patient underwent laminectomy, during which intraoperative motor signals were lost. A planned hemivertebrectomy at L1 was performed prior to an L4 laminectomy, untethering of the filum terminale, and posterior spinal fusion from T11 to L2. After surgery, the patient experienced transient lower-extremity weakness, with her neurological function improving from baseline over the next 2 months. Ultimately, the goal of this surgery was to halt the progressive decline in motor function, which was successfully achieved. LESSONS: Much remains to be learned about the treatment of this complicated disease, especially in the setting of concomitant scoliosis. This case serves to exemplify the complex treatment paradigms that exist when attempting to manage this clinical syndrome and that more remains to be learned.