Biomechanical Analysis of 3-Level Anterior Cervical Discectomy and Fusion Under Physiologic Loads Using a Finite Element Model.

OBJECTIVE: Pseudarthrosis and adjacent segment degeneration (ASD) are 2 common complications after multilevel anterior cervical discectomy and fusion (ACDF). We aim to identify the potential biomechanical factors contributing to pseudarthrosis and ASD following 3-level ACDF using a cervical spine finite element model (FEM). METHODS: A validated cervical spine FEM from C2 to C7 was used to study the biomechanical factors in cervical spine intervention. The FEM model was used to simulate a 3-level ACDF with intervertebral spacers and anterior cervical plating with screw fixation from C4 to C7. The model was then constrained at the inferior nodes of the T1 vertebra, and physiological loads were applied at the top vertebra. The pure moment load of 2 Nm was applied in flexion, extension, and lateral bending. A follower axial force of 75 N was applied to reproduce the weight of the cranium and muscle force, was applied using standard procedures. The motion-controlled hybrid protocol was utilized to comprehend the adjustments in the spinal biomechanics. RESULTS: Our cervical spine FEM demonstrated that the cranial adjacent level (C3-4) had significantly more increase in range of motion (ROM) (+90.38%) compared to the caudal adjacent level at C7-T1 (+70.18%) after C4-7 ACDF, indicating that the cranial adjacent level has more compensatory increase in ROM than the caudal adjacent level, potentially predisposing it to earlier ASD. Within the C4-7 ACDF construct, the C6-7 level had the least robust fixation during fixation compared to C4-5 and C5-6, as reflected by the smallest reduction in ROM compared to intact spine (-71.30% vs. -76.36% and -77.05%, respectively), which potentially predisposes the C6-7 level to higher risk of pseudarthrosis. CONCLUSION: Biomechanical analysis of C4-7 ACDF construct using a validated cervical spine FEM indicated that the C3-4 has more compensatory increase in ROM compared to C7-T1, and C6-7 has the least robust fixation under physiological loads. These findings can help spine surgeons to predicate the areas with higher risks of pseudarthrosis and ASD, and thus developing corresponding strategies to mitigate these risks and provide appropriate preoperative counseling to patients.

Challenges to the orthopedic resident workforce during the first wave of COVID-19 pandemic: Lessons learnt from a global cross-sectional survey.

BACKGROUND: The COVID-19 pandemic has caused unprecedented concerns on the safety, well-being, quality of life(QOL), and training of the orthopedic resident physician workforce worldwide. Although orthopedic residency programs across the globe have attempted to redefine resident roles, educational priorities, and teaching methods, the global orthopedic residents' perspective with regards to their safety, well-being, QOL, and training, taking into account regional variances remains unknown. METHODS: A 56-item-questionnaire-based cross-sectional survey was conducted online during the COVID-19 pandemic involving 1193 orthopedic residents from 29 countries across six geographical regions to investigate the impact of the COVID-19 pandemic on the well-being, safety, and training of orthopedic residents at a global level, as well as to analyze the challenges confronted by orthopedic residency programs around the world to safeguard and train their resident workforce during this period. RESULTS: The total response rate was 90.3%(1077/1193). Time spent on residency-training activities decreased by 24.7 h/week (95% CI, -26.5 to -22.9,p < 0.001), with 50.2% (n = 541) residents performing duties outside their residency curriculum. 80.5% (n = 869) residents had no prior experience working in infectious outbreaks. A greater percentage of residents from Middle East, Asia and Europe were redeployed to the COVID-19 frontlines, p < 0.001. Only 46.5% (n = 491) and 58.4% (n = 600) of residents underwent training in critical care or PPE (Personal Protective equipment) usage, respectively; 28.5% (n = 302) residents (majority from Africa, Middle East, South America) reported lack of institutional guidelines to handle infectious outbreaks; 15.4% (n = 160) residents (majority from Africa, Asia, Europe) had concerns regarding availability of PPE and risk of infection. An increase in technology-based virtual teaching modalities was observed. The most significant stressor for residents was the concern for their family's health. Residents' QOL significantly decreased from 80/100 (IQR 70-90) to 65/100 (IQR 50-80) before and during the pandemic, p < 0.001. CONCLUSIONS: The COVID-19 pandemic has significantly impacted the safety, well-being, QOL, and training of the global orthopedic resident physician workforce to different extents across geographical regions. The findings of this study will aid educators, program leaderships, and policy makers globally in formulating flexible, generalizable, and sustainable strategies to ensure resident safety, well-being, and training, while maintaining patient care.

Delayed unrelated presentation of a lumbar burst fracture consequent to a remote episode of a single convulsive seizure: A diagnostic challenge.

Non-traumatic vertebral fractures occurring as a sole consequence of the violent muscle forces generated during the first episode of a GTCS(generalized tonic clonic seizure) in a previously healthy non-epileptic individual are very rare. Being clinically asymptomatic they are easily overseen at the time of initial presentation due to their rarity of occurrence and the presence of potentially distracting factors in the post-ictal phase. We present a 52-year-old healthy non-epileptic male who presented with unrelenting back pain and neurodeficit secondary to a four-month-old unstable burst fracture of the first lumbar vertebra sustained during an isolated single episode of a witnessed GTCS. A detailed inquiry revealed no history of a significant traumatic event either during the convulsive episode or thereafter. A meticulous history taking, a thorough clinical and neurological examination combined with a comprehensive radiological evaluation established the unusual etiology of the fracture and the presence of a thoracolumbar kyphotic deformity with compression of conus medullaris. A detailed neurological, and laboratory work-up, confirmed no attributable organic or metabolic cause for the seizure. His BMD(Bone Mineral Density) was normal. Patient was managed with posterior instrumented deformity correction by a posterior column shortening osteotomy, neural decompression and fusion of D12-L1 facets. Patient had complete neurological recovery with good clinical and functional outcomes at 28-months follow-up. A few cases of seizure-induced non-traumatic spinal fractures have been published in literature. A majority of these fractures occurred in individuals with either seizure-provoking risk factors (epileptics with recurrent seizures, brain tumors, drug overdose/withdrawal, metabolic disorders, or electrolyte imbalance) or in those with an increased susceptibility to fracture due to decreased BMD. This case demonstrates the rare occurrence of a non-traumatic vertebral fracture during the first episode of a GTCS in an otherwise healthy non-epileptic individual with normal BMD and no seizure-provoking risk factors. This is the first case report of a delayed unrelated presentation of a non-traumatic lumbar vertebral fracture with complications (spinal deformity and neurodeficit) consequent to a remote episode of a single convulsive seizure. It emphasizes the need for a high index of clinical suspicion,a meticulous history taking, thorough musculoskeletal and neurological examination in any individual presenting with a seemingly benign back pain following a remote isolated episode of seizure, even in the absence of overt trauma. A detailed radiological evaluation guided by a meticulous history taking and detailed clinical examination is essential to rule out a fracture unless proven otherwise. It also shows that a single convulsive seizure can result in a potentially unstable fracture that when neglected, can result in devastating complications like spinal deformity and neurodeficit. LEVEL OF EVIDENCE: Level IV.

The impact of COVID-19 pandemic on orthopaedic resident education: a nationwide survey study in South Korea.

PURPOSE: There have not been well-designed survey studies investigating the impact of the coronavirus disease 2019 (COVID-19) pandemic on orthopaedic resident education. METHODS: A 58-question, web-based survey was administered to orthopaedic residents in South Korea. A total of 229 orthopaedic residents from 43 hospitals completed the survey questionnaire. RESULTS: The average working time of 72.7 hours/week before the pandemic was decreased to 65.6 hours/week during the pandemic (p < 0.001). The time working in the operating room was significantly decreased during the pandemic, but not in the emergency centre and outpatient clinic. The education times for lecture and clinical case discussion were decreased during the pandemic (both, p < 0.001), respectively. While the use of traditional teaching methods was decreased, the use of online-based teaching methods was increased (p < 0.001). However, satisfaction level with online-based teaching methods was significantly lower compared with that of traditional teaching methods. The average working time exposed to the patients with COVID-19 was 9.7 hours/week. About 47.6% of orthopaedic residents experienced isolation or quarantine. The average score for quality of life, which was 68.9 out of 100 scores before the pandemic, decreased to 61.7 during the pandemic (p < 0.001). The most stressful factor for orthopaedic residents during the pandemic was family/relative health, followed by their own health and residency program. CONCLUSION: The COVID-19 pandemic had a significant impact on orthopaedic resident education in South Korea. Therefore, flexible and sustainable strategies are necessary to prepare for the future as well as the current pandemic situation.

Occipital condyle screws: indications and technique.

Occipitocervical instability is a life threatening and disabling disorder caused by a myriad of pathologies. Restoring the anatomical integrity and stability of the occipitocervical junction (OCJ) is essential to achieve optimal clinical outcomes. Surgical stabilization of the OCJ is challenging and technically demanding. There is a paucity of options available for anchorage in the cephalad part of the construct in occipitocervical fixation systems due to the intricate topography of the craniocervical junction combined with the risk of injury to the surrounding anatomical structures. Surgical techniques and instrumentation for stabilizing the unstable OCJ have undergone several modifications over the years and have primarily depended on occipital squama-based fixations. At present, the occipital-plate-screw-rod construct is the most commonly adopted technique of stabilizing the OCJ. In certain distinct scenarios like posterior fossa craniectomy (absence of occipital squama for screw placement), malignancy and infection of occipital squama (poor screw purchase in the diseased occipital bone) and in revision surgery for failed occipitocervical stabilization, occipital plate-based instrumentation is not feasible. To overcome these difficulties, recently, a novel technique of occipitocervical stabilization, using the occipital condyle (OC) as the cephalad anchor, namely the direct occipital condyle screw (OCS) fixation was described. Several cadaveric and biomechanical studies have suggested that OCSs are feasible options as additional augmentative anchors in a standard occipital plate-screw-rod construct or as salvage cephalad anchors in previous failed occipital-plate-screw-rod constructs. The OCS placement technique has a steep learning curve. We have done a review of the techniques of OCS fixation and have described the indications, biomechanical and technical considerations, preoperative planning, surgical technique, complications, advantages and limitations of OCS based occipitocervical fixation.

Cervical spine pathology and treatment: a global overview.

Cervical spine pathology is becoming increasingly prevalent with an aging world population and is associated with significant morbidity, affecting all areas of the world. This review was undertaken to provide a global perspective on cervical spine pathology, including epidemiology, burden of disease, access to care, and plan of care in both developed and developing low- and middle-income countries (LMICs). We found that epidemiology, access to care, plan of care, and health outcomes were relatively similar between nations with similar economies. However, these aspects change dramatically when comparing developing nations to LMICs, with LMICs displaying substantial barriers to care and subsequently higher rates of morbidity and mortality. There is currently a need for large-scale, global, prospective multicenter studies that analyze not only the epidemiology and treatment of cervical spine pathology, but also consider patient outcomes.

The 2019 Cervical Spine Research Society (CSRS) Asia Pacific Traveling Fellowship.

The Cervical Spine Research Society (CSRS) is dedicated to advancing the care of patients with cervical spine pathology. The authors present here highlights of the 2019 CSRS-Asia Pacific Traveling Fellowship.

Does Preserving or Restoring Lumbar Lordosis Have an Impact on Functional Outcomes in Tuberculosis of the Lumbosacral Region?

STUDY DESIGN: Single-center retrospective cohort analysis. OBJECTIVES: To analyze the impact of loss of global lumbar lordosis (GLL) on functional outcomes in tuberculosis of the lumbar and lumbosacral spine and to define strategies to restore or preserve the physiological lumbar lordosis. SUMMARY OF BACKGROUND DATA: In tuberculosis of lumbosacral spine, loss of lumbar lordosis (LL) leads to altered lumbosacral biomechanics. All available studies have assessed treatment outcomes with respect to physical well-being, neurologic improvement, bone healing, and changes in radiologic parameters. None have studied the correlation between functional outcomes and LL following treatment. We reviewed 63 patients with tuberculosis of lumbar and lumbosacral spine, with an attempt to analyze the impact of loss of GLL on functional outcomes and have defined strategies to restore the same. METHODS: We retrospectively reviewed 63 patients with lumbar and lumbosacral tuberculosis, treated conservatively (n = 33) or surgically (n = 30) from March 2007 to July 2013. Average follow-up was 43.1±7.2 months. The correlation between posttreatment GLL and the functional outcome (Oswestry Disability Index), measured at 36 months' follow-up, was analyzed. RESULTS: All patients showed good bone healing (at 8.4±1.5 months), significant improvement in neurology, VAS scores, ESR and CRP, p<0.001. Mean loss of GLL in the conservatively treated group was 6.4°±5.7°, whereas there was an average gain of 10.9°±9.9° of GLL with surgery. In all patients with minimal disability at the end of treatment, the final GLL was above 40°. In patients with severe disability and in a few with moderate disability, the posttreatment GLL was below 40°. Pearson's test showed a strong negative correlation between final posttreatment GLL and the degree of disability (r = -0.867, p<0.001). CONCLUSIONS: Early disease with minimal loss of lordosis can be managed conservatively, whereas in advanced disease with gross hypolordosis/kyphosis, posterior stabilization with or without global spinal reconstruction is essential to regain LL. The management of lumbosacral tuberculosis should aim at preserving or restoring the normal LL to achieve good functional outcomes. LEVEL OF EVIDENCE: Level III.

Unilateral sacroiliitis: differentiating infective and inflammatory etiology by magnetic resonance imaging and tissue studies.

PURPOSE: Unilateral sacroiliitis (US) is an uncommon disease with varied etiology. The differentiation between infective and inflammatory causes for US based on MRI alone is often difficult. We studied the efficacy of MRI findings in comparison with tissue studies in the diagnosis of US. METHODS: A retrospective analysis of patients who presented with US and evaluated with MRI, biopsy for histopathology and tissue cultures was performed. Patients with bilateral sacroiliitis, traumatic and postpartum sacroiliitis were excluded. Based on defined MRI criteria, the patients were divided into two groups-infective (group A) and inflammation (group B). RESULTS: In total, 33 patients (mean age-33.4 ± 17.2 years) with MRI features of US had presented with unilateral gluteal pain (100%) and positive Patrick's test (91.9%). Based on the MRI features of severe subchondral marrow edema, widening of joint space, intra-articular abscess and periarticular muscle abscess, infective sacroiliitis (A) was diagnosed in 20/33 (60.6% cases). A total of 13/33 (39.3%) patients had features of inflammation (B), based on the following MRI criteria-subchondral sclerosis with minimal edema, erosions, maintained joint space without abscess/destruction. Tissue evidence of infection was positive in 13/20 (65%) patients in group A while it was negative in all group B patients. CONCLUSION: MRI had high sensitivity (71%) and 100% specificity in diagnosing inflammatory sacroiliitis while it had low specificity, but 100% sensitivity for diagnosing infective sacroiliitis. Hence, patients diagnosed as inflammatory sacroiliitis in MRI are unlikely to benefit from further tissue studies while percutaneous biopsy is recommended in patients diagnosed in MRI as infective sacroiliitis.

Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population.

STUDY DESIGN: Computed tomographic (CT) morphometric analysis. PURPOSE: To assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement. OVERVIEW OF LITERATURE: Limitations of occipital squama-based OCF has led to development of two novel OC-based OCF techniques. METHODS: Morphometric analysis was performed on the OCs of 70 Indian adults. The feasibility of placing a 3.5-mm-diameter screw into OCs was investigated. Safe trajectories and screw lengths for OC screws and C0-C1 transarticular screws without hypoglossal canal or atlantooccipital joint compromise were estimated. RESULTS: The average screw length and safe sagittal and medial angulations for OC screws were 19.9±2.3 mm, ≤6.4°±2.4° cranially, and 31.1°±3° medially, respectively. An OC screw could not be accommodated by 27% of the population. The safe sagittal angles and screw lengths for C0-C1 transarticular screw insertion (48.9°±5.7° cranial, 26.7±2.9 mm for junctional entry technique; 36.7°±4.6° cranial, 31.6±2.7 mm for caudal C1 arch entry technique, respectively) were significantly different than those in other populations. The risk of vertebral artery injury was high for the caudal C1 arch entry technique. Screw placement was uncertain in 48% of Indians due to the presence of aberrant anatomy. CONCLUSIONS: There were significant differences in the metrics of OC-based OCF between Indian and other populations. Because of the smaller occipital squama dimensions in Indians, OC-based OCF techniques may have a higher application rate and could be a viable alternative/salvage option in selected cases. Preoperative CT, including three-dimensional-CT-angiography (to delineate vertebral artery course), is imperative to avoid complications resulting from aberrant bony and vascular anatomy. Our data can serve as a valuable reference guide in placing these screws safely under fluoroscopic guidance.

Midterm radiologic and functional outcomes of minimally-invasive fixation of unstable pelvic fractures using anterior internal fixator(INFIX) and percutaneous iliosacral screws.

BACKGROUND: Anterior pelvic external fixation is associated with pin site infections, aseptic loosening with loss of reduction, frame bulkiness hindering patient mobilization and consequent difficulties in inpatient nursing. We performed a single-center prospective series to evaluate the feasibility, safety, limitations and midterm radiologic and functional outcomes of an alternative minimally invasive pelvic internal fixation technique using an anterior subcutaneous pelvic internal fixator (INFIX) and percutaneous iliosacral screws in unstable pelvic ring fractures. METHODS: Fifteen consecutive patients with vertically and/or rotationally unstable pelvic fractures, presenting to a Level-1 trauma center were treated with closed reduction, appropriate posterior stabilization with percutaneous iliosacral screws and anterior INFIX application. Outcomes were analyzed with respect to the quality of fracture reduction (Matta's radiologic criteria), ease of inpatient nursing, patient mobility and comfort, functional outcomes at final follow-up (Majeed score, SF-12 score), social reintegration and complications. RESULTS: Most common injury pattern was AO/OTA type 61-C pelvic fracture in thirteen patients. Mean procedure time and intra-operative blood loss were, 57.1+/-4.9 min (range,51-68 min) and 115.3+/-26.7 ml (range,80-170 ml) respectively. Mean follow-up was 34.9+/-4.1 months (range,31-42 months). Fracture reduction was excellent in twelve and good in three patients (Matta's criteria). Functional outcomes were excellent in eight and good in seven patients (Majeed score). Mean SF-12 scores for physical and mental health were 48.58+/-5.61 and 50.89+/-3.97 respectively. Thirteen patients returned to their pre-injury jobs. All fifteen patients reintegrated into society without any restrictions. INFIX was removed at a mean post-operative period of 7.3+/-1.5 months (range,5.5-11 months). Complications included, lateral femoral cutaneous nerve irritation(n = 1), superficial wound infection(n = 1) and loss of reduction(n = 2). CONCLUSION: Minimally invasive pelvic stabilization using INFIX and percutaneous iliosacral screws is easy to learn and apply, achieves good fracture reduction and definitive stabilization with minimum complications and offers excellent functional outcomes at a minimum follow-up of 31 months. LEVEL OF EVIDENCE: Level IV.

Global Reconstruction for Extensive Destruction in Tuberculosis of the Lumbar Spine and Lumbosacral Junction: A Case Report.

Study Design Case report. Objective To analyze the surgical difficulties in restoring global spinal stability and to describe an effective surgical option for tuberculosis with extensive destruction of the lumbosacral spine. Advanced tuberculosis with destruction of the lumbosacral spine can result in a kyphosis or hypolordosis, leading to back pain, spinal instability, and neurological deficits. The conventional treatment goals of lumbosacral tuberculosis are to correct and prevent a lumbar kyphosis, treat or prevent a neurological deficit, and restore global spinal stability. Instrumentation at the lumbosacral junction is technically demanding due to the complex local anatomy, the unique biomechanics, and the difficult fixation in the surrounding diseased bone. Methods We report a 21-year-old woman with tuberculosis from L1 to S2 with back pain and spinal instability. The radiographs showed a kyphosis of the lumbar spine. The magnetic resonance imaging and computed tomography scans revealed extensive destruction of the lumbar and lumbosacral spine. Spinopelvic stabilization combined with anterior debridement and reconstruction with free fibular strut graft was performed. Results The radiographs at follow-up showed a good correction of the kyphosis and excellent graft incorporation and fusion. Conclusions Anterior column reconstruction with a fibular strut graft helps restore and maintain the vertebral height. Posterior stabilization with spinopelvic fixation can be an effective surgical option for reconstructing the spine in extensive lumbosacral tuberculosis with sacral body destruction, requiring long fusions to the sacrum. It augments spinal stability, prevents graft-related complications, and accelerates the graft incorporation and fusion, thereby permitting early mobilization and rehabilitation. In spinal tuberculosis, antitubercular therapy may have to be prolonged in cases with large disease load, based on the clinicoradiographic and laboratory parameters.