A radiological analysis of pelvic fixation trajectories: patient series.

BACKGROUND: Three well-defined methods for pelvic fixation are used for biomechanical support in spine fusion constructs: iliac, recessed iliac, and S2-alar-iliac (S2AI) screws. The authors compared the maximum screw sizes that could be placed with these techniques by using image-guidance software and high-resolution computed tomography scans from 20 randomly selected patients. Six trajectories were plotted per side, beginning at recognized starting points (standard or recessed posterior superior iliac spine [PSIS] or S2AI screw) and ending at the anterior inferior iliac spine (AIIS) or supra-acetabular notch (SAN). OBSERVATIONS: The mean maximum screw length and width ranged from 80.0 ± 32.2 mm to 140.8 ± 22.6 mm and from 8.25 ± 1.2 mm to 13.0 ± 2.7 mm, respectively, depending on the trajectory. Statistically significant differences in length were found between the standard and recessed PSIS trajectories to the AIIS (p < 0.001) and between the standard PSIS-to-AIIS trajectory and the S2AI-to-AIIS (p = 0.007) or S2AI-to-SAN (p < 0.001) trajectories. The most successful trajectory was the PSIS to SAN (95%, 38/40). LESSONS: The traditional iliac screw trajectory enabled the longest and widest screw trajectories and highest rate of successful screw placement with the fewest theoretical breaches more reliably than recessed and S2AI trajectories. These findings may help surgeons plan for maximum screw purchase for pelvic fixation.

Epidemiology of Gunshot-Related Spinal Injuries and Related Risk Factors for In-Hospital Mortality in the United States from 2015-2019: A National Trauma Data Bank Analysis.

Firearm injuries in the U.S. pose a significant public health burden, but data on gunshot wounds (GSWs) specifically involving the spine are scarce. We examined epidemiological trends in GSWs to the spine and associated spinal cord injury (SCI) and mortality rates. This was a cross-sectional study of data from level I-III trauma centers in the U.S. participating in the American College of Surgeons National Trauma Data Bank (ACS NTDB) in 2015-2019. We identified adult and pediatric patients presenting with GSW and evaluated those with Abbreviated Injury Scale codes indicating spinal involvement and SCI. We assessed in-hospital mortality and GSW-related SCI. A total of 5,021,316 patients were enrolled in the ACS NTDB. Of the 107,233 patients (2.1% of total) presenting with GSW, 9023 (8.4%) patients had spine involvement. Overall rates of GSW and spinal GSW were similar across years. The most common cause of spinal GSW injury was assault (86.7%). The cervical spine was involved in 24.2% of patients, thoracic spine in 42.8%, and lumbar spine in 39.7%. Cervical SCI was present in 8.7% of all spinal GSW (35.7% of cervical GSW), thoracic SCI in 17.4% (40.6% of thoracic GSW), and lumbar SCI in 8.1% (20.3% of lumbar GSW). The mean patient age was 29.0 ± 12.2 years, 88.5% were male, 62.4% were black, 23.7% were white, and 13.9% were another race. Blood alcohol content was ≥0.08 in 12.1%, and illicit drugs were positive in 24.4%. In-hospital mortality was high in patients with spinal GSWs (8.1%), and mortality was significantly higher with cervical involvement (18.1%), cervical SCI (30.7%), or thoracic incomplete SCI (13.6%) on univariate analysis. On multi-variate analysis of age (excluding patients <16 years of age), sex, Injury Severity Score (ISS), complete SCI, and spinal area of involvement, only greater patient age (age 40-65 years: adjusted odds ratio [aOR] 1.52, 95% confidence interval [CI] 1.09-2.11, p = 0.014; age >65 years: aOR 3.90, 95% CI 2.10-7.27, p < 0.001) and higher ISS (ISS 9-15: aOR 6.65, 95% CI 2.38-18.54, p < 0.001; ISS 16-24: aOR 18.13, 95% CI 6.65-49.44, p < 0.001; ISS >24: aOR 68.44, 95% CI 25.39-184.46, p < 0.001) were independently associated with in-hospital mortality risk after spinal GSW. These results demonstrate that spinal GSW is not uncommon and that older patients with more severe systemic injuries have higher in-hospital mortality risk.

Mid-term and Long-term Outcomes After Total Cervical Disk Arthroplasty Compared With Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

STUDY DESIGN: A meta-analysis of randomized controlled trials (RCTs). OBJECTIVE: The aim of this study was to compare mid-term to long-term outcomes of cervical disk arthroplasty (CDA) with those of anterior cervical discectomy and fusion (ACDF) for the treatment of symptomatic cervical degenerative disk disease. SUMMARY OF BACKGROUND DATA: After ACDF to treat symptomatic cervical degenerative disk disease, the loss of motion at the index level due to fusion may accelerate adjacent-level disk degeneration. CDA was developed to preserve motion and reduce the risk of adjacent segment degeneration. Early-term to mid-term clinical outcomes from RCTs suggest noninferiority of CDA compared with ACDF, but it remains unclear whether CDA yields better mid-term to long-term outcomes than ACDF. MATERIALS AND METHODS: Two independent reviewers searched PubMed, Embase, and the Cochrane Library for RCTs with at least 60 months of follow-up. The risk ratio or standardized mean difference (and 95% CIs) were calculated for dichotomous or continuous variables, respectively. RESULTS: Eighteen reports of 14 RCTs published in 2014-2023 were included. The pooled analysis demonstrated that the CDA group had a significantly greater improvement in neurological success and Neck Disability Index than the ACDF group. The ACDF group exhibited a significantly better improvement in the Short Form-36 Health Survey Physical Component Summary than the CDA group. Radiographic adjacent segment degeneration was significantly lower in the CDA group at 60- and 84-month follow-ups; at 120-month follow-up, there was no significant difference between the 2 groups. Although the overall rate of secondary surgical procedures was significantly lower in the CDA group, we did not observe any significant difference at 60-month follow-up between the CDA and ACDF group and appreciated statistically significant lower rates of radiographic adjacent segment degeneration, and symptomatic adjacent-level disease requiring surgery at 84-month and 108- to 120-month follow-up. The rate of adverse events and the neck and arm pain scores in the CDA group were not significantly different from those of the ACDF group. CONCLUSIONS: In this meta-analysis of 14 RCTs with 5- to 10-year follow-up data, CDA resulted in significantly better neurological success and Neck Disability Index scores and lower rates of radiographic adjacent segment degeneration, secondary surgical procedures, and symptomatic adjacent-level disease requiring surgery than ACDF. ACDF resulted in improved Short Form-36 Health Survey Physical Component Summary scores. However, the CDA and ACDF groups did not exhibit significant differences in overall changes in neck and arm pain scores or rates of adverse events.

Closed cervical traction techniques: moving into the 21st century.

Closed cervical traction for reducing dislocating cervical injuries, deformity correction, or discectomy distraction has been implemented in its modern form since the 1930s. Cervical traction state of the art has not changed significantly since the 1960s, with most reductions performed by using Gardner-Wells tongs or halo traction; however, there are many limitations of traditional weight-pulley traction, including limited reduction efficacy and patient safety shortcomings. In this paper, the authors review the history of cervical traction in the 20th century and the limitations of current traction techniques and describe a novel traction device developed at the University of Utah with robotic actuator load or position control and real-time force-sensing capabilities. Preliminary biomechanical testing results using the novel device in an extension spring loading model, with intact cadavers, and in iatrogenic facet injury cadaveric models demonstrated preliminary safety and efficacy of the device. The authors believe this and future research efforts aimed toward improving the efficacy and safety of cervical traction will help advance the field into the 21st century.

Motorized Robotic Closed Cervical Traction: Biomechanical Proof of Concept.

STUDY DESIGN: Biomechanical study. OBJECTIVE: To demonstrate that robotic cervical traction can apply closed cervical traction as effectively as manual weight-and-pulley traction in extension spring and cadaveric models. SUMMARY OF BACKGROUND DATA: Closed cervical traction is used to reduce subaxial cervical spine dislocation injuries and to distract the intervertebral space during cervical spine surgery. Weight-and-pulley cervical traction relies on cumbersome and imprecise technology without any safeguard to prevent over-traction or weights being pulled/released inadvertently. METHODS: A prototype robotic traction device was designed and manufactured by the authors with real-time tensile force measurement, ±1-lbs (5 N) force application accuracy, locking/non-backdriveable linear actuators with actuator position sensing, 200-lbs (900 N) maximum force capability, up to 20° of flexion/extension manipulation, <25-lbs (111 N) device weight, and compatibility with Gardner-Wells tongs or Mayfield head clamp. The device was tested using an extension spring model and an intact fresh cadaver specimen to assess applied and desired force over time and radiographic changes in the cervical spine as traction force increased. The cadaver was tested in manual traction initially and then robotic traction in 10-lbs (50 N) increments up to 80-lbs (355 N) to compare methods. RESULTS: The prototype device met or exceeded all requirements. In extension spring testing, the device reached the prescribed forces of both 25-lbs (111 N) and 80-lbs (355 N) accurately and maintained the desired weight. In cadaveric testing, radiographic outcomes were equivalent between the prototype and manual weight-and-pulley traction at 80-lbs (355 N; disk space measurements within ±10% for all levels), and the device reached the desired weight within±1-lbs (5 N) of accuracy at each weight interval. CONCLUSION: This preliminary work demonstrates that motorized robotic cervical traction can safely and effectively apply controlled traction forces.

Natural history of pituitary carcinoma with metastasis to the cervical spine: illustrative case.

BACKGROUND: Pituitary carcinoma is a rare tumor of the adenohypophysis with noncontiguous craniospinal dissemination and/or systemic metastases. Given the rarity of this malignancy, there is limited knowledge and consensus regarding its natural history, prognosis, and optimal treatment. OBSERVATIONS: The authors present the case of a 46-year-old woman initially treated with invasive prolactin-secreting pituitary macroadenoma who developed metastatic disease of the cervical spine 6 years later. The patient presented with acutely worsening compressive cervical myelopathy and required posterior cervical decompression, tumor resection, and instrumented arthrodesis for posterolateral fusion. LESSONS: This case underscores the importance of long-term monitoring of hormone levels and having a high clinical suspicion for metastatic disease to the spine in patients presenting with acute myelopathy or radiculopathy in the setting of previously treated invasive secreting pituitary adenoma.

Using Frailty Measures to Predict Functional Outcomes and Mortality After Type II Odontoid Fracture in Elderly Patients: A Retrospective Cohort Study.

STUDY DESIGN: Single-center retrospective cohort study. OBJECTIVES: Type II odontoid fractures occur disproportionately among elderly populations and cause significant morbidity and mortality. It is a matter of debate whether these injuries are best managed surgically or conservatively. Our goal was to identify how treatment modalities and patient characteristics correlated with functional outcome and mortality. METHODS: We identified adult patients (>60 years) with traumatic type II odontoid fractures. We used multivariate regression controlling for patient demographics, Glasgow Coma Scale (GCS) score, Charlson Comorbidity Index (CCI), modified Rankin Scale (mRS) score, modified Frailty Index (mFI-5 and mFI-11), fracture displacement, and conservative vs operative treatment. RESULTS: Of the 59 patients (mean age 77.9 years), 24 underwent surgical intervention and 35 underwent conservative management. Operatively managed patients were younger (73.4 vs 80.6 years, P < .001) and had higher degree of fracture displacement (3.5 vs 1.0 mm, P = .002) than conservatively managed patients but no other differences in baseline characteristics. Twenty-four patients (40.7%) died within the study period (median time to death: 376 days). There were no differences between treatment groups in functional outcomes (mRS or Frankel Grade) or mortality (33.3% in operative group vs 45.7%, P = .34). There was a statistically significant correlation between higher presentation mRS score and subsequent mortality on multivariate analysis (OR = 2.06, 95% CI 1.04-4.10, P = .039), whereas surgical intervention, age, GCS score, CCI, mFI-5, mFI-11, sex, and fracture displacement were not significantly correlated. CONCLUSIONS: Mortality after type II odontoid fractures in elderly patients is common. mRS score at presentation may help predict mortality more accurately than other patient factors.

O-Arm Accuracy and Radiation Exposure in Adult Deformity Surgery.

OBJECTIVE: In long thoracolumbar deformity surgery, accurate screw positioning is critical for spinal stability. We assessed pedicle and pelvic screw accuracy and radiation exposure in patients undergoing long thoracolumbar deformity fusion surgery (≥4 levels) involving 3-dimensional fluoroscopy (O-Arm/Stealth) navigation. METHODS: In this retrospective single-center cohort study, all patients aged >18 years who underwent fusion in 2016-2018 were reviewed. O-Arm images were assessed for screw accuracy. Effective radiation doses were calculated. The primary outcome was pedicle screw accuracy (Heary grade). Secondary outcomes were pelvic fixation screw accuracy, radiation exposure, and screw-related perioperative and postoperative complications or revision surgery within 3 years. RESULTS: Of 1477 pedicle screws placed in 91 patients (mean 16.41 ± 5.6 screws/patient), 1208 pedicle screws (81.8%) could be evaluated by 3-dimensional imaging after placement. Heary Grade I placement was achieved in 1150 screws (95.2%), Grade II in 47 (3.9%), Grade III in 10 (0.82%), Grade IV in 1 (0.08%), and Grade V in 0; Grade III-V were replaced intraoperatively. One of 60 (1.6%) sacroiliac screws placed showed medial cortical breach and was replaced. The average O-Arm-related effective dose was 29.54 ± 14.29 mSv and effective dose/spin was 8.25 ± 2.65 mSv. No postoperative neurological worsening, vascular injuries, or revision surgeries for screw misplacement were recorded. CONCLUSIONS: With effective radiation doses similar to those in interventional neuroendovascular procedures, the use of O-Arm in multilevel complex deformity surgery resulted in high screw accuracy, no need for surgical revision because of screw malposition, less additional imaging, and no radiation exposure for the surgical team.

Postoperative ileus risk after posterior thoracolumbar fusion performed with total intravenous anesthesia versus inhaled anesthesia.

OBJECTIVE: There has been an increase in the use of total intravenous anesthesia (TIVA) for intraoperative neuromonitoring during thoracolumbar posterior spinal fusion (PSF). Although prior studies have identified risk factors for postoperative ileus (PI) after PSF, to the authors' knowledge, PI rates in patients receiving inhaled anesthetic versus TIVA have not been evaluated. In this study the authors analyzed whether TIVA is associated with greater risk of PI in PSF patients. METHODS: In this retrospective single-institution cohort study, all patients undergoing PSF at the authors' tertiary academic institution from May 2014 to December 2020 were included. Patients undergoing anterior/lateral approaches or who had concurrent abdominal procedures unrelated to ileus in the same admission were excluded. PI was defined using radiographic and/or clinical diagnoses (postoperative radiographs, abdominal CT, and/or ICD-9 or -10 codes) and was confirmed via chart review. The use of TIVA or inhaled anesthetic was captured from the anesthesia record; patients were excluded if they were missing anesthesia technique data. Postoperative occurrence of PI was compared between patients who had TIVA or inhaled anesthetics while controlling for collected demographic, clinical, and surgical variables. RESULTS: Of the 2819 patients meeting inclusion criteria, 283 (10.0%) had PI (mean ± SD age 59.3 ± 15.8 years; 155 [54.8%] male). The mean patient length of stay was 7.7 ± 5.0 days, which was significantly longer than that of patients without PI (4.9 ± 3.9 days, p < 0.001). Patients with PI had more levels fused (46% of PI patients with ≥ 5 levels fused vs 25% of non-PI patients, p < 0.001) and longer operations (6.0 ± 2.2 vs 5.4 ± 1.9 hours, p < 0.001). TIVA patients were more likely than inhalation-only patients to experience PI, but this finding did not reach significance on univariate analysis (11.0% PI rate vs 8.9%, p = 0.06). After propensity matching 125 non-PI patients and 50 PI patients by age, sex, operative time, and number of levels fused, there was a significant difference in intraoperative opiate dosing between TIVA and inhalational patients (275.7 ± 187.5 intravenous morphine milligram equivalents vs 120.9 ± 155.5, p < 0.001). On multivariate analysis of PI outcome, TIVA was an independently significant predictor (OR 1.45, p = 0.02), as was anesthesia time (OR per hour increase: 1.09, p = 0.03) and ≥ 8 levels fused (OR 1.86, p = 0.01). CONCLUSIONS: In a large cohort of PSF patients, TIVA was associated with a higher rate of PI compared with inhaled anesthetic. This effect is likely due to higher intraoperative opiate use in these patients.

Neurosurgery at Pearl Harbor: Ralph Cloward's legacy.

Ralph B. Cloward (1908-2000) was the sole neurosurgeon present during the Japanese attack on Pearl Harbor on December 7, 1941. Cloward operated on 42 patients in a span of 4 days during the attacks and was awarded a commendation signed by President Franklin D. Roosevelt in 1945 for his wartime efforts. During the attacks, he primarily treated depressed skull fractures and penetrating shrapnel wounds, but he also treated peripheral nerve and spine injuries in the aftermath. His techniques included innovative advancements such as tantalum cranioplasty plates, electromagnets for intracranial metallic fragment removal, and the application of sulfonamide antibiotic powder within cranial wounds, which had been introduced by military medics for gangrene prevention in 1939 and described for penetrating cranial wounds in 1940. Despite the severity of injuries encountered, only 2 soldiers died in the course of Cloward's interventions. As the sole neurosurgeon in the Pacific Theater until 1944, he remained in Honolulu through World War II's duration and gained immense operative experience through his wartime service. Here, the authors review the history of Cloward's remarkable efforts, techniques, injury patterns treated, and legacy.

L4 Corpectomy: Surgical Approaches and Mitigating the Risk of Femoral Nerve Injuries.

OBJECTIVE: Because of the challenging anatomic location, corpectomies are performed less often at the fourth lumbar vertebral body than at other levels. Our objective was to review the literature of L4 corpectomy and anterior column reconstruction. METHODS: A literature search in the Medline/PubMed database was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify all relevant cases and cases series describing corpectomies of the L4 vertebral body using "lumbar" AND "corpectomy" as search terms. We present an illustrative case to describe the technique. RESULTS: We identified 18 articles with 30 patients who met the search criteria. Including our case illustration, the most common approach used was the lateral retroperitoneal approach (n = 17, 54.8%), of which 8 (26.7%) were performed via a transpsoas approach. Seven (23%) patients underwent corpectomy through a posterior approach, 4 (12.9%) through an anterior retroperitoneal approach, and 3 (10%) through combined anterior and lateral retroperitoneal. The overall complications rate was 19.3% including 1 case each of femoral nerve injury and iatrogenic lumbar nerve root injury. CONCLUSIONS: Corpectomies of the L4 vertebral body are challenging. None of the various approaches described clearly demonstrates any superiority in mitigating the risk of neural complications. Decision making about which surgical approach to use should be based on patient-specific characteristics.

Laminectomy at T4 and T5 for Resection of Symptomatic Cavernous Malformation.

Although rare, intramedullary spinal cavernous malformations have a 1.4%-6.8% annual hemorrhage risk and can cause significant morbidity.1 Prior hemorrhage and size >1 cm are risk factors for future hemorrhage that, in addition to notable or progressive symptoms, may justify early surgical intervention.1,2 In this video, we present key steps in surgical management of a large, symptomatic thoracic cavernous malformation. A 56-year-old woman presented with worsening lower extremity weakness, imbalance, and difficulty ambulating. Strength was 3/5 in her right lower extremity and 4/5 in her left lower extremity. She had an incomplete T4 sensory level and hyperreflexia. Magnetic resonance imaging demonstrated a heterogeneous "popcorn"-appearing expansile intradural intramedullary 2.2- × 1.2-cm lesion at T4-5, consistent with a cavernous malformation. Angiography was deferred given the characteristic magnetic resonance imaging appearance. Given her progressive symptoms (including weakness), lesion size, and good health, resection was recommended. Using neurological monitoring, a T4-5 laminectomy, midline myelotomy, and piecemeal microsurgical resection of the lesion was performed, clearly identifying the cavernoma-spinal cord interface and avoiding spinal cord retraction. Histopathology confirmed a cavernoma. Postoperatively, the patient had improved left lower extremity strength and stable right lower extremity strength but worsened dorsiflexion (1/5), which improved with rehabilitation. At 1-year follow-up, she had full strength in her left lower extremity and 4/5 in her right lower extremity, with mild paresthesias below T10. Consistent with prior series demonstrating low complication rates and good long-term neurological outcomes,2 microsurgical resection of selected symptomatic intramedullary spinal cavernous malformations can halt neurological decline and potentially improve neurological function.

FEBio finite element model of a pediatric cervical spine.

OBJECTIVE: The underlying biomechanical differences between the pediatric and adult cervical spine are incompletely understood. Computational spine modeling can address that knowledge gap. Using a computational method known as finite element modeling, the authors describe the creation and evaluation of a complete pediatric cervical spine model. METHODS: Using a thin-slice CT scan of the cervical spine from a 5-year-old boy, a 3D model was created for finite element analysis. The material properties and boundary and loading conditions were created and model analysis performed using open-source software. Because the precise material properties of the pediatric cervical spine are not known, a published parametric approach of scaling adult properties by 50%, 25%, and 10% was used. Each scaled finite element model (FEM) underwent two types of simulations for pediatric cadaver testing (axial tension and cardinal ranges of motion [ROMs]) to assess axial stiffness, ROM, and facet joint force (FJF). The authors evaluated the axial stiffness and flexion-extension ROM predicted by the model using previously published experimental measurements obtained from pediatric cadaveric tissues. RESULTS: In the axial tension simulation, the model with 50% adult ligamentous and annulus material properties predicted an axial stiffness of 49 N/mm, which corresponded with previously published data from similarly aged cadavers (46.1 ± 9.6 N/mm). In the flexion-extension simulation, the same 50% model predicted an ROM that was within the range of the similarly aged cohort of cadavers. The subaxial FJFs predicted by the model in extension, lateral bending, and axial rotation were in the range of 1-4 N and, as expected, tended to increase as the ligament and disc material properties decreased. CONCLUSIONS: A pediatric cervical spine FEM was created that accurately predicts axial tension and flexion-extension ROM when ligamentous and annulus material properties are reduced to 50% of published adult properties. This model shows promise for use in surgical simulation procedures and as a normal comparison for disease-specific FEMs.

Solitary manifestations of primary B-lymphoblastic lymphoma of the spine: Systematic literature review with case illustration.

BACKGROUND: Given the locally destructive osteolytic nature of primary B-cell lymphoblastic lymphoma (B-LBL) of the spine, careful attention is needed to identify clinical signs and symptoms as well as radiological findings of spinal instability because these lesions may warrant resection, decompression, and instrumentation with posterolateral fusion. Our objective was to summarize the presenting symptoms, clinical features, potential treatment modalities, and clinical outcome of cases described in the literature. METHODS: We undertook a systematic literature review to identify all relevant cases and case series describing primary manifestations B-LBL of the spine using Pubmed/Medline. We summarized the findings in accordance with the PRISMA guidelines. We also present a case illustration. RESULTS: Together with our case, 9 cases of primary B-LBL of the spine were identified in 6 male and 3 female patients (age 8-58 years, median 31 years). Back pain was the most common symptom, and five patients also had neurological signs of spinal cord compression. T1-weighted MRI contrast enhancement was seen in 5 cases. Surgery was performed in 5 patients with progression of neurological deficits. Steroid treatment was also given in 3 patients preoperatively. Seven patients had chemotherapy after diagnosis. During follow-up of 1 month to 1 year, 2 cases of recurrence and 4 cases of complete remission were noted; however, with the short follow-up time, patient prognosis overall remains unclear. CONCLUSIONS: Primary B-LBL of the spine represents a rare clinical entity whose management mandates a multidisciplinary approach. Careful attention must be paid to the neurological status of the patient, as well as to imaging that may highlight potential local instability of the spine.

An updated management algorithm for incorporating minimally invasive techniques to treat thoracolumbar trauma.

OBJECTIVE: Minimally invasive surgery (MIS) techniques can effectively stabilize and decompress many thoracolumbar injuries with decreased morbidity and tissue destruction compared with open approaches. Nonetheless, there is limited direction regarding the breadth and limitations of MIS techniques for thoracolumbar injuries. Consequently, the objectives of this study were to 1) identify the range of current practice patterns for thoracolumbar trauma and 2) integrate expert opinion and literature review to develop an updated treatment algorithm. METHODS: A survey describing 10 clinical cases with a range of thoracolumbar injuries was sent to 12 surgeons with expertise in spine trauma. The survey results were summarized using descriptive statistics, along with the Fleiss kappa statistic of interrater agreement. To develop an updated treatment algorithm, the authors used a modified Delphi technique that incorporated a literature review, the survey results, and iterative feedback from a group of 14 spine trauma experts. The final algorithm represented the consensus opinion of that expert group. RESULTS: Eleven of 12 surgeons contacted completed the case survey, including 8 (73%) neurosurgeons and 3 (27%) orthopedic surgeons. For the 4 cases involving patients with neurological deficits, nearly all respondents recommended decompression and fusion, and the proportion recommending open surgery ranged from 55% to 100% by case. Recommendations for the remaining cases were heterogeneous. Among the neurologically intact patients, MIS techniques were typically recommended more often than open techniques. The overall interrater agreement in recommendations was 0.23, indicating fair agreement. Considering both literature review and expert opinion, the updated algorithm indicated that MIS techniques could be used to treat most thoracolumbar injuries. Among neurologically intact patients, percutaneous instrumentation without arthrodesis was recommended for those with AO Spine Thoracolumbar Classification System subtype A3/A4 (Thoracolumbar Injury Classification and Severity Score [TLICS] 4) injuries, but MIS posterior arthrodesis was recommended for most patients with AO Spine subtype B2/B3 (TLICS > 4) injuries. Depending on vertebral body integrity, anterolateral corpectomy or mini-open decompression could be used for patients with neurological deficits. CONCLUSIONS: Spine trauma experts endorsed a range of strategies for treating thoracolumbar injuries but felt that MIS techniques were an option for most patients. The updated treatment algorithm may provide a foundation for surgeons interested in safe approaches for using MIS techniques to treat thoracolumbar trauma.

Lateral Suboccipital Craniotomy With C1-C2 Hemilaminectomies and C1-C3 Fusion for the Treatment of a C1-C2 Synovial Cyst Causing Spinal Cord Compression: 2-Dimensional Operative Video.

Atlantoaxial synovial cysts are a rare cause of cervical myelopathy. Here we describe a case of a 26-yr-old woman who presented with progressively decreasing right arm and leg strength and associated gait imbalance. On examination, she had diffuse weakness in the right upper and lower extremities, a positive right-sided Hoffman sign, and clonus in the right lower extremity. Computed tomography demonstrated an os odontoideum and a retro-odontoid cyst. Magnetic resonance imaging demonstrated a T1 hypointense, T2 hyperintense, slightly rim-enhancing retro-odontoid cyst causing a marked narrowing of the spinal canal, with resultant flattening and leftward deviation of the spinal cord. The patient consented to undergo cyst fenestration via a right suboccipital craniotomy and right C1-C2 hemilaminectomies, along with a C1-C3 instrumented posterior spinal fusion. This approach was chosen because it allows for cyst fenestration and instrumentation of the hypermobile cervical spine within the same incision. After the dura was opened and the arachnoid was dissected, the cyst was visualized compressing the spinal cord. The cyst was fenestrated just inferior to the C1 nerve rootlets, resulting in immediate egress of a gelatinous content; thereafter, all accessible cyst wall portions were removed. Fusion was performed with lateral mass screws at C1 and C3 and pars screws at C2. Pathological analysis described the cyst content as reactive fibrovascular tissue with cholesterol deposition. There were no complications associated with the procedure, and the patient's right-sided weakness had nearly resolved by postoperative day 1. Patient consent was granted for publication.

Spinal Cord Injury Management on the Front Line: ABCs of Spinal Cord Injury Treatment Based on American Association of Neurological Surgeons/Congress of Neurological Surgeons Guidelines and Common Sense.

Spinal cord injury (SCI) affects approximately 54 per 1 million people annually in the United States. Treatment strategies for this patient population focus on initial stabilization and early intervention. The cornerstones of early management are clinical assessment, characterization of the injury, medical optimization, and definitive surgical treatment, including surgical stabilization and/or decompression. This article discusses the important strategies in caring for patients with SCI that are supported with significant literature.

Febio finite element models of the human cervical spine.

Finite element (FE) analysis has proven to be useful when studying the biomechanics of the cervical spine. Although many FE studies of the cervical spine have been published, they typically develop their models using commercial software, making the sharing of models between researchers difficult. They also often model only one part of the cervical spine. The goal of this study was to develop and evaluate three FE models of the adult cervical spine using open-source software and to freely provide these models to the scientific community. The models were created from computed tomography scans of 26-, 59-, and 64-year old female subjects. These models were evaluated against previously published experimental and FE data. Despite the fact that all three models were assigned identical material properties and boundary conditions, there was notable variation in their biomechanical behavior. It was therefore apparent that these differences were the result of morphological differences between the models.

Finite element modeling to compare craniocervical motion in two age-matched pediatric patients without or with Down syndrome: implications for the role of bony geometry in craniocervical junction instability.

OBJECTIVE: Instability of the craniocervical junction (CCJ) is a well-known finding in patients with Down syndrome (DS); however, the relative contributions of bony morphology versus ligamentous laxity responsible for abnormal CCJ motion are unknown. Using finite element modeling, the authors of this study attempted to quantify those relative differences. METHODS: Two CCJ finite element models were created for age-matched pediatric patients, a patient with DS and a control without DS. Soft tissues and ligamentous structures were added based on bony landmarks from the CT scans. Ligament stiffness values were assigned using published adult ligament stiffness properties. Range of motion (ROM) testing determined that model behavior most closely matched pediatric cadaveric data when ligament stiffness values were scaled down to 25% of those found in adults. These values, along with those assigned to the other soft-tissue materials, were identical for each model to ensure that the only variable between the two was the bone morphology. The finite element models were then subjected to three types of simulations to assess ROM, anterior-posterior (AP) translation displacement, and axial tension. RESULTS: The DS model exhibited more laxity than the normal model at all levels for all of the cardinal ROMs and AP translation. For the CCJ, the flexion-extension, lateral bending, axial rotation, and AP translation values predicted by the DS model were 40.7%, 52.1%, 26.1%, and 39.8% higher, respectively, than those for the normal model. When simulating axial tension, the soft-tissue structural stiffness values predicted by the DS and normal models were nearly identical. CONCLUSIONS: The increased laxity exhibited by the DS model in the cardinal ROMs and AP translation, along with the nearly identical soft-tissue structural stiffness values exhibited in axial tension, calls into question the previously held notion that ligamentous laxity is the sole explanation for craniocervical instability in DS.