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Unstable thoracolumbar spinal injuries benefit from surgical fixation. However, perioperative complications significantly affect outcomes in surgicallytreated spine patients. We evaluated associations between risk factors and postoperative complications in patients surgically treated for thoracolumbar spine fractures.We conducted a retrospective multicenter study collating data from 21 spine centers across 9 countries on the treatment of AOSpine types B and C injuries of the thoracolumbar spine treated via a posterior approach. Comparative analysis was performed between patients with postoperative complications and those without. Univariate and multivariable analyses were performed.Among 535 patients, at least 1 complication occurred in 43%. The most common surgical complication was surgical-site infection (6.9%), while the most common medical complication was urinary tract infection (13.8%). Among 136 patients with American Spinal Injury Association (ASIA) Impairment Scalelevel A disability, 77.9% experienced at least 1 complication. The rate of complications also rose sharply among patients waiting3 days for surgery (P0.001), peaking at 68.4% among patients waiting ≥30 days. On multivariable analysis, significant predictors of complications were surgery at a governmental hospital (odds ratio = 3.38, 95% confidence interval = 1.73-6.60), having ≥1 comorbid illness (2.44, 1.61-3.70), surgery delayed due to health instability (2.56, 1.50-4.37), and ASIA Impairment Scalelevel A (3.36, 1.78-6.35), while absence of impairment (0.39, 0.22-0.71), ASIAlevel E (0.39, 0.22-0.67) and, unexpectedly, delay caused by operating room unavailability (0.60, 0.36-0.99) were protective.Types B and C thoracolumbar spine injuries are associated with a high risk of postoperative complications, especially common at governmental hospitals, and among patients with comorbidity, health instability, longer delays to surgery, and worse preoperative neurologic status.

Study design: A systematic review and meta-analysis. Objective: This meta-analysis aimed to compare percutaneous (PPS) versus open pedicle screw (OPS) fixation for treatment of thoracic and lumbar spondylodiscitis. Summary of background data: Pyogenic spondylodiscitis of the thoracic and lumbar spine can produce instability, deformity, and/or neurological compromise. When medical treatment is unsuccessful, surgical treatment is indicated, with the conventional open approach the usual standard of care. However, percutaneous techniques can be advantageous in medically vulnerable patients. Materials and methods: A literature search was performed using the PubMed, Web of Science, and Scopus databases, looking for comparative articles on pyogenic spondylodiscitis requiring surgical stabilization with pedicle screws. This systematic review is reported according to PRISMA guidelines. Results: From 215 articles initially identified, 7 retrospective studies were analyzed, encapsulating an overall sample of 722 patients: 405 male (56.1%) and 317 female (43.9%). The treatment modality was PPS fixation in 342 patients (47.4%) and OPS fixation in 380 (52.6%). For PPS, operating time was 29.75 minutes ( P

To determine characteristics of Latin American (LA) productivity in spine surgery published worldwide between 2004 and 2021 compared between periods and global literature.A comprehensive search about LA productivity in the field of spine surgery using the Scopus and PubMed databases was performed in February 2022. The results were limited to articles published in indexed journals from 2004 to 2021.A total of 1447 publications were identified in the study period. The number of publications has increased across evaluated decades, with 583 between 2004 and 2013 (58.3/year) and 864 between 2014 and 2021 (108/year), and a yearly increase was demonstrated (P = 0.0001). Comparing the most productive year in the first (2012) and last decade (2020), a 1.79-fold increase was demonstrated. Brazil ranked first in productivity (51.14%), followed by Mexico (26.40%) and Argentina (8.64%). Coluna/Columna published the largest number, with 309 articles (21.35%). The top 10 institutions published at least 475 (32.82%) and the most productive was the University of Campinas (Brazil, 74).This scientometric study is one of the first regional evaluations worldwide. The number of publications in the spine surgery field in Latin America has continued to increase over evaluated decades from 58.3 per year to 108, and a 1.79-fold increase between the most productive years for each decade. Brazil is still the greatest contributor (51.14%), with Mexico (26.40%) and Argentina (8.64%) as growing contributor countries. Most publications were classified as Level of Evidence 4, and this result reflects the importance of continuous research development in the quality of research for our region.

Study design: Systematic Review and Meta-analysis. Objective: Surgical alternatives to treat lumbar spinal stenosis and instability include indirect (ALIF, OLIF, and LLIF) and direct (TLIF or posterior lumbar interbody fusion) decompression and fusion interventions. Although both approaches have proven to be effective in reducing symptoms, it is unknown if there is any difference in effectiveness between them. In this systematic review and meta-analysis, we aimed to evaluate postoperative pain and disability in patients treated whit indirect vs direct decompression and fusion approaches. Methods: We conducted a systematic review of the literature consulting several databases and identified studies that enrolled patients diagnosed with degenerative lumbar spinal stenosis and instability treated with indirect or direct decompression and fusion techniques. Our primary endpoints were the visual analogue scale, Oswestry Disability Index, and the Japanese Orthopedics Association Back Pain Evaluation Questionnaire 1 year after the procedure. Secondary outcomes included complication rate, blood loss, and surgical time. Results: Nine retrospective and comparative studies were included enrolling a total of 1004 participants. Both surgical strategies had satisfactory clinical outcomes with no significant difference at 1 year. Although the complication rate was similar for both groups, the profile of the adverse events was different. In addition, patients treated with indirect decompression and fusion had significantly less blood loss and operative times. Conclusions: Indirect and direct decompression and fusion techniques are similarly effective in treating patients with lumbar spinal stenosis and instability. The ID group had significantly lower intraoperative blood loss and surgical time values.

Background Reporting complications and/or adverse events after spinal surgical procedures enables the estimation of their prevalence and of their impact on patient outcomes. However, the documentation of complications is relatively infrequent and highly heterogeneous. The purpose of this study was to evaluate the quality of complication and adverse event reporting in spinal surgery literature. Methods A systematic review of the literature from 5 international, peer-reviewed, indexed spinal journals was performed. Included studies were published between January and December 2020 and reported the surgical results of spinal procedures. Data on the level of evidence and study design were collected and analyzed as well as whether the studies were single-center or multicenter studies. The quality of complication reports was evaluated through a 5-item checklist, with 5 questions divided into 3 parts: definition, evaluation, and report. Results Complications associated with spinal surgical procedures were reported in 292 studies. According to the level of evidence, significantly higher reporting quality was seen in level I and II studies compared with level III and IV studies (P = 0.003). Regarding the 5-item checklist, 49% (143/292) of studies fulfilled the definition section, 16.4% (48/292) fulfilled the evaluation section, and 92% (270/292) fulfilled the report section. Conclusions Overall quality assessment when reporting complications in surgical spinal studies showed that only 13% (38/292) of publications that reported complications as part of the outcomes exhibited all items of the 5-item checklist. Additionally, significantly better reports were observed in level I studies compared with level II–IV studies.

Osteoporotic vertebral compression fractures of the thoracolumbar spine can progress to Kummell’s disease, an avascular vertebral osteonecrosis. Vertebral augmentation (VA)—vertebroplasty and/or kyphoplasty—is the main treatment modality, but additional short-segment fixation (SSF) has been recommended concomitant to VA. The aim is to compare clinical and radiological outcomes of VA + SSF versus VA alone. Systematic review, including comparative articles in Kummell’s disease, was performed. This study assessed the following outcome measurements: visual analog scale (VAS), Oswestry Disability Index (ODI), anterior vertebral height (AVH), local kyphotic angle (LKA), operative time, blood loss, length of stay, and cement leakage. Six retrospective studies were included, with 126 patients in the VA + SSF group and 152 in VA alone. Pooled analysis showed the following: VAS, non-significant difference favoring VA + SSF: MD –0.61, 95% CI (–1.44, 0.23), I2 91%, p = 0.15; ODI, non-significant difference favoring VA + SSF: MD –9.85, 95% CI (–19.63, –0.07), I2 96%, p = 0.05; AVH, VA + SSF had a non-significant difference over VA alone: MD –3.21 mm, 95% CI (–7.55, 1.14), I2 92%, p = 0.15; LKA, non-significant difference favoring VA + SSF: MD –0.85°, 95% CI (–5.10, 3.40), I2 95%, p = 0.70. There were higher operative time, blood loss, and hospital length of stay for VA + SSF (p

STUDY DESIGN: Retrospective review of multicentric data. OBJECTIVES: To estimate the time from initial visit to surgery in adolescent idiopathic scoliosis (AIS) patients and the main reasons for the time to surgery in a multicenter study. METHODS: This retrospective study evaluated 509 patients with AIS from 16 hospitals across six Latin American countries. From each hospital's deformity registry, the following patient data were extracted: demographics, main curve Cobb angle, Lenke Classification at the initial visit and time of surgery, time from indication-for-surgery to surgery, curve progression, Risser skeletal-maturity score and causes for surgical cancelation or delay. Surgeons were asked if they needed to change the original surgical plan due to curve progression. Data also were collected on each hospital's waiting list numbers and mean delay to AIS surgery. RESULTS: 66.8% of the patients waited over six months and 33.9% over a year. Waiting time was not impacted by the patient's age when surgery first became indicated (p = 0.22) but waiting time did differ between countries (p

Objective We sought to compare the outcomes of single-position (SP) circumferential lumbar interbody fusion in lateral decubitus versus dual-position (DP) fusion. Methods A systematic literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines in PubMed, Web of Science, and Scopus databases to identify comparative studies reporting the outcomes of SP lumbar interbody fusion versus DP. For risk of bias assessment, the ROBINS-I (risk of bias in nonrandomized studies of interventions) tool was used. Results Four comparative studies were included from an initial search of 3780 papers. All 4 studies were retrospective cohort studies comparing outcomes of SP versus DP LLIF. A total of 349 patients were operated using SP versus 254 using DP. All studies involved reported operating time, estimated blood loss, length of stay, change in segmental lordosis, and complications. From a general perspective, baseline variables were similar in both groups in all the studies and all reported a significant decrease in operative time and length of stays with SP. Conclusions Literature comparing SP versus lateral-then-prone lumbar fusion shows a tendency toward shorter operating time and hospital stays in SP lumbar fusion while maintaining similar perioperative outcomes.

Many efforts are expended to improve health care quality in the surgical treatment of spinal conditions. However, the prevalence of reporting complications in spinal surgeries is highly heterogeneous, which is partially due to the lack of a universal and comprehensive system.A systematic review of the literature was performed in 5 international and indexed spine journals from January to December 2020. All clinical studies that had surgical procedures in any spinal region were classified according to level of evidence, study design, category of spinal condition, and primary outcome. The prevalence and quality of complication reporting were evaluated through a checklist.Of 455 articles screened, complications were reported in 64.2% (292 articles). A significant higher prevalence of reports was observed in randomized compared with nonrandomized studies (P0.05). In 89 articles, at least 1 classification was used to report complications, with 12 different classification systems employed in the total sample. Timing to record complications was as follows: 47 (16.1%) articles reported complications at 30 days, 31 (10.6%) reported complications at 90 days, and 88 (30.1%) reported complications during all follow-ups. In 126 (43.1%) articles, complications were not mentioned.Almost one-third of spine surgical studies did not report complications in their results despite reporting clinical outcomes. The evidence quality of the study was directly related with the reporting of complications. A high heterogeneity regarding complication reporting was seen in the literature.

The complex anatomy of the upper cervical spine resulted in numerous separate classification systems of upper cervical spine trauma. The AOSpine upper cervical classification system (UCCS) was recently described; however, an independent agreement assessment has not been performed.To perform an independent evaluation of the AOSpine UCCS.Agreement study.Eighty four patients with upper cervical spine injuries.Inter-observer agreement; intra-observer agreement.Complete imaging studies of 84 patients with upper cervical spine injuries, including all morphological types of injuries defined by the AOSpine UCCS were selected and classified by six evaluators (from three different countries). The 84 cases were presented to the same raters randomly after a 4-week interval for repeat evaluation. The Kappa coefficient (κ) was used to determine inter- and intra-observer agreement.The interobserver agreement was almost perfect when considering the fracture site (I, II or III), with κ=0.82 (0.78-0.83), but the agreement according to the site and type level was moderate, κ=0.57 (0.55-0.65). The intra-observer agreement was almost perfect considering the injury, with κ=0.83 (0.78-0.86), while according to site and type was substantial, κ=0.69 (0.67-0.71).We observed only a moderate inter-observer agreement using this classification. We believe our results can be explained because this classification attempted to organize many different injury types into a single scheme.

Background: Preoperative optimization in patients undergoing posterior spinal fusion is essential to limit the number and severity of postoperative complications. Here, we, additionally, evaluated the impact of hypoalbuminemia on morbidity and mortality after posterior spinal fusion surgery. Methods: This retrospective analysis was performed using data from a prospective multicentric database (ACSNSQIP:2015–2020) regarding patients undergoing posterior spinal fusions. Factors studied included; baseline demographics and 30-day postoperative complications (i.e., reoperations, readmissions, and mortality rates). Results: There were 6805 patients who met the inclusion criteria. They averaged 62 years of age and had an average BMI of 30.2. Within the 30-day postoperative period, 634 (9.3%) sustained complications; 467 (6.9%) were readmitted, 263 (3.9%) required reoperations, and 37 (0.5%) expired. Although multiple preoperative risk factors were analyzed, hypoalbuminemia, severe hypoalbuminemia, and dialysis were the strongest independent risk factors associated with complications (i.e., reoperations, readmissions, and mortality). Conclusion: Hypoalbuminemia, severe hypoalbuminemia, and dialysis were significant predictors for morbidity and mortality after posterior spinal fusion surgery.

Background Two-dimensional fluoroscopy-guided percutaneous pedicle screw placement is currently the most widely applied instrumentation for minimally invasive treatment of spinal injuries requiring stabilization. Although this technique has advantages over open instrumentation, it also presents new challenges and specific complications. The objective of this study was to provide recommendations developed from the experience of several spinal surgeons at different minimally invasive spine surgery reference centers to solve specific problems and prevent complications during the learning curve of this technique. Methods An AO Spine Latin America minimally invasive spine surgery study group analyzed the most frequent complications and challenges occurring during the placement of >14,000 two-dimensional fluoroscopy–guided percutaneous pedicle screws at different centers over 15 years. Twenty tips considered most relevant to performing this technique, excluding problems directly related to specific brands of instruments, were presented. Results The 20 tips included the following: (1) positioning; (2) clean and painless; (3) fewer x-rays; (4) check the clock; (5) beveled tip; (6) transverse-rib-pedicle; (7) double Jamshidi; (8) hammer the Kirschner wire; (9) bent tip; (10) too loose, too tight; (11) new trajectory; (12) manual control; (13) start over; (14) Kirschner wire first; (15) adhesive drape control; (16) bend the rod; (17) lower rods; (18) freehand inner; (19) posterior fusion; (20) revision. Conclusions Implementation of these tips might improve performance of this technique and reduce the complications related to percutaneous pedicle screw placement.

Study Design: Multicentric retrospective study, Level of evidence III. Objective: The objective of this multicentric study was to analyze the prevalence and risk factors of early postoperative complications in adult spinal deformity patients treated with fusion. Additionally, we studied the impact of complications on unplanned readmission and hospital length of stay. Methods: Eight spine centers from 6 countries in Latin America were involved in this study. Patients with adult spinal deformity treated with fusion surgery from 2017 to 2019 were included. Baseline and surgical characteristics such as age, sex, comorbidities, smoking, number of levels fused, number of surgical approaches were analyzed. Postoperative complications at 30 days were recorded according to Clavien-Dindo and Glassman classifications. Results: 172 patients (120 females/52 males, mean age 59.4 ± 17.6) were included in our study. 78 patients suffered complications (45%) at 30 days, 43% of these complications were considered major. Unplanned readmission was observed in 35 patients (20,3%). Risk factors for complications were: Smoking, previous comorbidities, number of levels fused, two or more surgical approaches and excessive bleeding. Hospital length of stay in patients without and with complications was of 7.8 ± 13.7 and 17 ± 31.1 days, respectively ( P 0.0001). Conclusion: The prevalence of early postoperative complications in adult spinal deformity patients treated with fusion was of 45% in our study with 20% of unplanned readmissions at 30 days. Presence of complications significantly increased hospital length of stay.

Study Design: Literature review and transversal study. Objective: Advances in new technologies give the surgeons confidence to manage complex spine conditions with a lower morbidity rate. This has changed the expectations of patients and medical payers and foreshadows the shift now underway: the use of minimally invasive techniques. The ethical considerations of learning directly on patients require a change in the education and training programs. Methods: The education paradigm has changed, and surgical training on minimally invasive surgery of the spine (MISS) techniques should follow a “curriculum.” The assessment of skill proficiency while learning the MISS techniques must be measurable to objectively show the performance gained over time and the changes that should be performed during training. Different strategies include “ex vivo” and “in vivo” training. Results: We have worked on a curriculum in which the participants can perceive the growth in their knowledge through the different educational opportunities. There are 3 levels: basic, advanced, and masters. Conclusions: We developed an educational curriculum for MISS rationale and techniques, that showed to be effective and interesting in our region.

Study Design Questionnaire-based survey. Objectives Surgical site infection (SSI) is a common complication in spine surgery but universal guidelines for SSI prevention are lacking. The objectives of this study are to depict a global status quo on implemented prevention strategies in spine surgery, common themes of practice and determine key areas for future research. Methods An 80-item survey was distributed among spine surgeons worldwide via email. The questionnaire was designed and approved by an International Consensus Group on spine SSI. Consensus was defined as more than 60% of participants agreeing to a specific prevention strategy. Results Four hundred seventy-two surgeons participated in the survey. Screening for Staphylococcus aureus (SA) is not common, whereas preoperative decolonization is performed in almost half of all hospitals. Body mass index (BMI) was not important for surgery planning. In contrast, elevated HbA1c level and hypoalbuminemia were often considered as reasons to postpone surgery. Cefazoline is the common drug for antimicrobial prophylaxis. Alcohol-based chlorhexidine is mainly used for skin disinfection. Double-gloving, wound irrigation, and tissue-conserving surgical techniques are routine in the operating room (OR). Local antibiotic administration is not common. Wound closure techniques and postoperative wound dressing routines vary greatly between the participating institutions. Conclusions With this study we provide an international overview on the heterogeneity of SSI prevention strategies in spine surgery. We demonstrated a large heterogeneity for pre-, peri- and postoperative measures to prevent SSI. Our data illustrated the need for developing universal guidelines and for testing areas of controversy in prospective clinical trials.

To perform an interobserver and intraobserver agreement evaluation of the new AO Spine-DGOU classification system for osteoporotic thoracolumbar fractures (OFc).Complete imaging studies of 97 patients (radiographs, computed tomography scans, and magnetic resonance imaging) with osteoporotic thoracolumbar fractures were selected and classified using the OFc by 6 spine surgeons (3 senior surgeons with more than 15 years of experience and 3 surgeons with less than 15 years). After a 4-week interval, the same cases were presented to the same evaluators in a random sequence for a new classification assessment. The weighted kappa coefficient (wκ) was used to determine the interobserver and intraobserver agreement.The interobserver agreement was moderate, wκ = 0.59 (95% confidence interval 0.54-0.64). The intraobserver agreement was fair, wκ = 0.35 (95% confidence interval 0.29-0.40). Interobserver agreement slightly improved for junior staff between first and second evaluation, suggesting a learning effect. Better agreement was obtained by senior staff at the interobserver and intraobserver agreement.This independent assessment demonstrated that new OFc allows moderate interobserver agreement and fair intraobserver agreement. Further studies are necessary prior to its widespread adoption.

Study design Retrospective review of multicentric data. Objectives The modified 5-item frailty index is a relatively new tool to assess the post-operative complication risks. It has been recently shown a good predictive value after posterior lumbar fusion. We aimed to compare the predictive value of the modified 5-item frailty index in cervical, thoracic and lumbar surgery. Methods The American College of Surgeons - National Surgical Quality Improvement Program (ACS-NSQIP) Database 2015-2020 was used to identify patients who underwent elective posterior cervical, thoracic, or lumbar fusion surgeries for degenerative conditions. The mFI-5 score was calculated based on the presence of 5 co-morbidities: congestive heart failure within 30 days prior to surgery, insulin-dependent or noninsulin-dependent diabetes mellitus, chronic obstructive pulmonary disease or pneumonia, partially dependent or totally dependent functional health status at time of surgery, and hypertension requiring medication. Multivariate analysis was used to assess the independent impact of increasing mFI-5 score on the postoperative morbidity while controlling for baseline clinical characteristics. Results 53 252 patients were included with the mean age of 64.2 ± 7.2. 7946 suffered medical complications (14.9%), 1565 had surgical complications (2.9%), and 3385 were readmitted (6.3%), 363 died (.68%) within 30 days postoperative (6.3%). The mFI-5 items score was significantly associated with higher rates of complications, readmission, and mortality in cervical, thoracic, and lumbar posterior fusion surgery. Conclusion The modified 5-item frailty score is a reliable tool to predict complications, readmission, and mortality in patients planned for elective posterior spinal fusion surgery.

STUDY DESIGN Global cross-sectional survey. OBJECTIVE To validate the AO Spine Subaxial Cervical Spine Injury Classification by examining the perceived injury severity by surgeon across AO geographical regions and practice experience. SUMMARY OF BACKGROUND DATA Previous subaxial cervical spine injury classifications have been limited by subpar interobserver reliability and clinical applicability. In an attempt to create a universally validated scheme with prognostic value, AO Spine established a subaxial cervical spine injury classification involving four elements: (1) injury morphology, (2) facet injury involvement, (3) neurologic status, and (4) case-specific modifiers. METHODS A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. Respondents graded the severity of each variable of the classification system on a scale from zero (low severity) to 100 (high severity). Primary outcome was to assess differences in perceived injury severity for each injury type over geographic regions and level of practice experience. RESULTS A total of 189 responses were received. Overall, the classification system exhibited a hierarchical progression in subtype injury severity scores. Only three subtypes showed a significant difference in injury severity score among geographic regions: F3 (floating lateral mass fracture, p:0.04), N3 (incomplete spinal cord injury, p:0.03), and M2 (critical disk herniation, p:0.04). When stratified by surgeon experience, pairwise comparison showed only 2 morphological subtypes, B1 (bony posterior tension band injury, p:0.02) and F2 (unstable facet fracture, p:0.03), and one neurologic subtype (N3, p:0.02) exhibited a significant difference in injury severity score. CONCLUSIONS The AO Spine Subaxial Cervical Spine Injury Classification System has shown to be reliable and suitable for proper patient management. The study shows this classification is substantially generalizable by geographic region and surgeon experience; and provides a consistent method of communication among physicians while covering the majority of subaxial cervical spine traumatic injuries.Level of Evidence: 4.

Study Design: Cross-sectional survey. Objectives: Assessment of subaxial cervical facet injuries using the AO Spine Subaxial Cervical Spine Injury Classification System is based on CT scan findings. However, additional radiological evaluations are not directly considered. The aim of this study is to determine situations in which spine surgeons request additional radiological exams after a facet fracture. Methods: A survey was sent to AO Spine members from Latin America. The evaluation considered demographic variables, routine use of the Classification, as well as the timepoint at which surgeons requested a cervical MRI, a vascular study, and/ or dynamic radiographs before treatment of facet fractures. Results: There was 229 participants, mean age 42.9 ± 10.2 years; 93.4% were men. Orthopedic surgeons 57.6% with 10.7 ± 8.7 years of experience in spine surgery. A total of 86% used the Classification in daily practice. An additional study (MRI/vascular study/and dynamic radiographs) was requested in 53.3%/9.6%/43.7% in F1 facet injuries; 76.0%/20.1%/50.2% in F2; 89.1%/65.1%/28.4% in F3; and 94.8%/66.4%/16.6% in F4. An additional study was frequently required: F1 72.5%, F2 86.9%, F3 94.7%, and F4 96.1%. Conclusions: Spine surgeons generally requested additional radiological evaluations in facet injuries, and MRI was the most common. Dynamic radiographs had a higher prevalence for F1/F2 fractures; vascular studies were more common for F3/F4 especially among surgeons with fewer years of experience. Private hospitals had a lower spine trauma cases/year and requested more MRI and more dynamic radiographs in F1/F2. Neurosurgeons had more vascular studies and dynamic radiographs than orthopedic surgeons in all facet fractures.

Objective We sought to identify delays for surgery to stabilize unstable thoracolumbar fractures and the main reasons for them across Latin America. Methods We reviewed the charts of 547 patients with type B or C thoracolumbar fractures from 21 spine centers across 9 Latin American countries. Data were collected on demographics, mechanism of trauma, time between hospital arrival and surgery, type of hospital (public vs. private), fracture classification, spinal level of injury, neurologic status (American Spinal Injury Association impairment scale), number of levels instrumented, and reason for delay between hospital arrival and surgical treatment. Results The sample included 403 men (73.6%) and 144 women (26.3%), with a mean age of 40.6 years. The main mechanism of trauma was falls (44.4%), followed by car accidents (24.5%). The most frequent pattern of injury was B2 injuries (46.6%), and the most affected level was T12-L1 (42.2%). Neurologic status at admission was 60.5% intact and 22.9% American Spinal Injury Association impairment scale A. The time from admission to surgery was >72 hours in over half the patients and over a week in >25% of them. The most commonly reported reasons for surgical delay were clinical instability (22.9%), lack of operating room availability (22.7%), and lack of hardware for spinal instrumentation (e.g., screws/rods) (18.8%). Conclusions Timing for surgery in this sample of unstable fractures was over 72 hours in more than half of the sample and longer than a week in about a quarter. The main reasons for this delay were clinical instability and lack of economic resources. There is an apparent need for increased funding for the treatment of spinal trauma patients in Latin America.

Objective To evaluate incidence and types of implant failure observed in a series of patients with spinal metastases (SM) treated with minimally invasive stabilization surgery without fusion. Methods In this multicenter, retrospective, observational study, we reviewed the files of patients >18 years old who underwent surgery for SM using percutaneous spinal stabilization without fusion with a minimum 3-month follow-up. The following variables were included: demographics, clinical findings, prior radiation history, SM location, epidural spinal cord compression scale, Spinal Instability Neoplastic Scale, neurological examination, and surgery-related data. Primary outcome measure was implant failure rate, as observed in patients' last computed tomography scan. Multivariable analysis was performed to identify baseline factors and factors associated with implant failure. Results Analysis included 72 patients. Mean age of patients was 62 years, 39 patients were men, and 75% of patients had an intermediate Spinal Instability Neoplastic Scale score. Tumor separation surgery was performed in 48.6% of patients. Short instrumentation was indicated in 54.2% of patients. Three patients (4.2%) experienced implant failure (2 screw loosening, 1 screw cut-out); none of them required revision surgery. In 73.6% of cases, survival was >6 months. No significant predictors of failure were identified in the multivariate analysis. Conclusions A low implant failure rate was observed over the short and medium term, even when short instrumentations without fusion were performed. These findings suggest that minimally invasive stabilization surgery without fusion may be an effective and safe way to treat complicated SM.

Study Design: Diagnostic study, level of evidence III. Objective: Pyogenic spondylodiscitis can cause deformity, neurological compromise, disability, and death. Recently, a new classification of spondylodiscitis based on magnetic resonance imaging was published. The objective of this study is to perform an independent reliability analysis of this new classification. Methods: We selected 35 cases from our database of different spine centers in Latin America and from the literature; 8 observers evaluated the classification and graded the scenarios according to the methodological grading of the classification developed by Pola et al. Cases were sent to the observers in a random sequence after 3 weeks to assess intraobserver reliability. The interobserver and intraobserver reliabilities were performed with Fleiss and Cohen statistics, respectively. Results: The overall Fleiss κ value for interobserver agreement was substantial, with 0.67 (95% CI = 0.43-0.91) in the first reading and 0.67 (95% CI = 0.45-0.89) in second reading for the main types of classification. The Cohen κ value for intraobserver agreement was also substantial, with 0.68 (95% CI = 0.45-0.92). The interobserver agreement analysis for the subtypes of this classification was overall substantial, with 0.60 (95% CI = 0.37-0.83) in the first reading and 0.61 (95% CI = 0.41-0.81) in the second reading. The overall intraobserver agreement for subtypes of the classification was also substantial, with 0.63 (95% CI = 0.34-0.93). Conclusion: The new classification developed by Pola et al showed substantial interobserver and intraobserver agreements. More studies are required to validate the usefulness of this classification especially in clinical practice.

Study Design: Cross-sectional study. Objective: The aim of this study was to evaluate the impact of the COVID-19 outbreak in spine surgeons in Latin America. Methods: A questionnaire was sent to Latin American spine surgeons from April 4 to 6, 2020. Surgeon characteristics were recorded. The impact of COVID-19 on economic well-being, work, and mental health were also determined. All variables were compared and analyzed. Results: Two hundred four surgeons answered the complete survey; most of them were male (96.6%), the average age was 47.7 years; 58.8% (n = 120) were orthopedic surgeons and 41.2% (n = 84) were neurosurgeons. The majority of the respondents were from Argentina (59.8%, n = 122), followed by Brazil (17.2%, n = 35), Chile (6.4%, n = 13), and Mexico (5.9%, n = 12). Most of the surgeons reported performing emergency procedures only during the pandemic (76.5%, n = 156). Half used telemedicine or online consultation modalities (54.4%, n = 111). The average concern about the financial situation due to the pandemic was 7.53 in a scale of 1 to 10 (10 being the worst scenario). Twenty-two percent (n = 45) of the surgeons had a score over 10 in the Patient Health Questionnaire (PHQ-9; scores higher than 10 needs referral to confirm depression diagnosis). Young age and neurosurgery as a specialty were associated with higher PHQ-9 scores. Conclusions: COVID-19 has an impact in the daily working practice and financial situation of spine surgeons in Latin America. The long-term psychological impact should be taken into consideration to avoid a heavier burden for health care providers.

Objective To evaluate access to the technologies and education needed to perform minimally invasive spine surgery (MISS) in Latin America. Methods We designed a questionnaire to evaluate surgeons’ practice characteristics, access to different technologies, and training opportunities for MISS techniques. The survey was sent to members and registered users of AO Spine Latin from January 6–20, 2020. The major variables studied were nationality, specialty (orthopedics or neurosurgery), level of hospital (primary, secondary, tertiary), number of surgeries performed per year by the spine surgeon, types of spinal pathologies commonly managed, and number of MISS performed per year. Other variables involved specific access to different technologies: intraoperative fluoroscopy, percutaneous screws, cages, tubular retractors, microscopy, intraoperative computed tomography, neuronavigation imaging, and bone morphogenetic protein. Finally, participants were asked about main obstacles to performing MISS and their access to education on MISS techniques in their region. Results The questionnaires were answered by 306 members of AO Spine Latin America across 20 different countries. Most answers were obtained from orthopedic surgeons (57.8%) and those with over 10 years of experience (42.4%). Most of the surgeons worked in private practice (46.4%) and performed >50 surgeries per year (44.1%), but only 13.7% performed >50 MISS per year, mainly to manage degenerative pathologies (87.5%). Most surgeons always had access to fluoroscopy (79%). Only 26% always had access to percutaneous screws, 24% to tubular retractors, 34.3% to cages (anterior lumbar interbody fusion, lateral lumbar interbody fusion, or transforaminal lumbar interbody fusion), and 43% to microscopy. Regarding technologies, 71% reported never having access to navigation, 83% computed tomography, and 69.3% bone morphogenetic protein. The main limitations expressed for widely used MISS technologies were the high implant costs (69.3%) and high navigation costs (49.3%). Most surgeons claimed access to online education activities (71%), but only 44.9% reported access to face-to-face events and 28.8% to hands-on activities, their limited access largely because the courses were expensive (62.7%) or few courses were available on MISS in their region (51.3%). Conclusions Most surgeons in Latin America have limited resources to perform MISS, even in private practice. The main constraints are implant costs, access to technologies, and limited face-to-face educational opportunities.

Background: Intraoperative neurophysiological monitoring (IOM) has become valuable in spine surgery. Unfortunately, it is not always available in many spine centers, especially in developing countries. Our aim was to evaluate the accessibility and barriers to IOM in spine surgery in Latin America. Methods: We designed a questionnaire to evaluate the characteristics of surgeons and their opinions on the usefulness of IOM for different spine operations. The survey was sent to 9616 members and registered users of AO Spine Latin America (AOSLA) from August 1, 2019, to August 21, 2019. Major variables studied included nationality, years of experience, specialty (orthopedics or neurosurgery), level of complexity of the hospital, number of spine surgeries performed per year by the spine surgeon, the types of spinal pathologies commonly managed, and how important IOM was to the individual surgeon. General questions to evaluate use included accessibility, limitations of IOM usage, management of IOM changes, and the legal value of IOM. The results were analyzed and compared between neurosurgeon and orthopedics, level of surgeon experience, and country of origin. Results: Questionnaires were answered by 200 members of AOSLA from 16 different countries. The most common responses were obtained from orthopedic surgeons (62%), those with more than 10 years of practice (54%); majority of surgeons performed more than 50 spine surgeries per year (69%) and treated mainly spine degenerative diseases (76%). Most surgeons think that IOM has a real importance during surgeries (92%) and not just a legal value. Although surgeons mostly considered IOM essential to scoliosis surgery in adolescents (70%), thoracolumbar kyphosis correction (68%), and intramedullary tumors (68%), access to IOM was limited to 57% for economic reasons. Of interest, in 64% of cases, where IOM was available and significant change occurred, the actual operative procedures were significantly altered. Conclusion: Despite the fact that 68% of spine surgeons believe IOM to be indispensable for complex spine surgery, cost remains the main barrier to its use/availability in Latin America.

Background: Our aim was to evaluate differences in neurosurgeons versus orthopedists access to technologies needed to perform minimally invasive spine surgeries (MISS) in Latin America. Methods: We sent a survey to members of AO Spine Latin America (January 2020), and assessed the following variables; nationality, level of hospital (primary, secondary, and tertiary), number of spinal operations performed per year, spinal pathologies addressed, the number of minimally invasive spine operations performed/year, and differences in access to MISS spinal technology between neurosurgeons and orthopedists. Results: Responses were returned from 306 (25.6) members of AO Spine Latin America representing 20 different countries; 57.8% of respondents were orthopedic surgeons and 42.4% had over 10 years of experience. Although both specialties reported a lack of access to most of the technologies, the main difference between the two was greater utilization/access of neurosurgeons to operating microscope (e.g., 84% of the neurosurgeons vs. 39% of orthopedic spine surgeons). Conclusion: Although both specialties have limited access to MISS spinal technologies, orthopedic spine surgeons reported significantly lower access to operating microscopes versus neurosurgeons (P < 0.01).

Background: The perception of major versus minor complications may vary according to surgeons, institutions, and different specialties. Here, we analyzed the geographic distribution of the different types/severities of the most frequent complications in spinal surgery, and assessed how the perception of spine surgeons about postoperative complications differed. Methods: We performed a cross-sectional study using a questionnaire, we developed to encompass different clinical scenarios of surgeons’ perceptions of spine surgery complications. The survey involved the members of AOSpine Latin America (LA) (January 28, 2017–March 15, 2017). The main variables studied included: specialty, age, years of experience, country, individual surgeon’s perception of different clinical scenarios, and the surgeon’s classification of complications for each scenario (e.g., major, minor, or none). Our results from LA were then analyzed and compared to North American (NA) responses. Results: Orthopedic surgeons represented about 58.2% (n = 412) of the 708 questionnaires answered. Of interest, 45.6% (n = 323) of those responding had >10 years of experience. The countries analyzed included Brazil (31.5%), Mexico (17.5%), Argentina (14.4%), Colombia (8.0%), and Venezuela (7.6%). Four of the 11 scenarios showed consensus in the results (e.g., average being over 82.5%). A tendency toward consensus was present in 45.4% of the clinical cases, while two out of 11 clinical cases did not present a consensus among surgeons. Of interest, the perception of complications was similar between cohorts (LA 85% vs. NA 80%). Conclusion: Significant consensus in the perception of complications was observed in most of the analyzed scenarios for both LA and NA. However, within the LA data, responses to different clinical scenarios varied.

Sacral chordomas are infrequent tumors that arise from remnants of the notochord. They are most often found in the sacrum and skull-base.1,2 These lesions rarely metastasize and usually have an indolent and oligosymptomatic clinical course. Chordomas show low sensitivity to standard radiation therapy and chemotherapy. Operative resection with wide resection margins offers the best long-term prognosis, including longer survival and local control.1,3 However, achieving a complete resection with oncological margins may be difficult because of the anatomic complexity of the sacrococcygeal region.4 The main complications of sacral resection include infections, wound closure defects, and anorectal and urogenital dysfunction. The rate of these complications is significantly increased when the tumor involves the S2 level or above. We report the case of a 64-yr-old male who presented with progressive sacrococcygeal pain and a feeling of incomplete evacuation. A heterogeneous, osteolytic lesion was found at the sacrococcygeal region. Full body imaging tests were negative for other lesions. A computed tomography (CT) guided biopsy was made. We usually use the midline approach in case we have to include the needle path in the resection. The pathology confirmed a sacrococcygeal, low-grade chordoma. We decided to perform an en bloc resection. A posterior, partial sacrectomy was planned distal to the S4 level.

Background: The Gorham–Stout syndrome (GSS), also known as phantom bone disease, is a rare bone condition of unknown etiology. Involvement of the spine is described in

Background: Spine fractures may involve the ligamentum flavum (LF). Here, we utilized the “ligamentum flavum gap,” defined by the discontinuity of the LF at the level of a vertebral fracture, to document a vertebral fracture. Methods: Utilizing X-rays, computed tomography (CT), and magnetic resonance (MR) studies, 10 patients with type B vertebral fractures were diagnosed with the ligamentum flavum gap (LFG: discontinuity of the LF) at the fracture levels. The fractures were located in 2 patients in the cervical and 8 in the thoracolumbar spine. Results: All 10 patients with vertebral fractures had complained of axial pain. Four also showed progressive thoracic kyphosis. Notably, all demonstrated a loss of continuity in the LF at the level of fracture “ligamentum flavum gap.” T2-weighted and short tau inversion recovery (STIR) MR sagittal studies were best at locating LFG at the level of a fracture. Conclusion: Here, we identified best on sagittal T2 and STIR-weighted MR studies 10 patients for whom discontinuity of the ligamentum flavum (LFG) correlated with the location of type B vertebral fractures.

Background The paraspinal, posterolateral, or Wiltse approach is an old technique that observes the principles of an MIS procedure. The aim of this study was to provide a step-by-step description from the literature of the Wiltse paraspinal approach and analyze its main advantages and limitations. Methods Here, we provide a step-by-step description of the Wiltse approach. Utilizing PubMed and Lilacs and the Mesh terms "Wiltse approach," "paraspinal approach," "muscle sparing approach," and "lumbar spine," we identified 10 papers. We then put together, based on these publications, a step-by-step analysis of the preparation, patient positioning, skin incision, fascial opening, dissection, bone identification, retractors, deperiostization, decompression, discectomy, instrumentation, arthrodesis, and closure for the Wiltse technique. Results Most papers underscored the minimally invasive aspects of the typical Wiltse approach. Advantages included minimal intraoperative bleeding, a shorter hospital length of stay, and a low infection rate. Conclusion The classical approach described by Wiltse is essentially minimally invasive, sparing both the muscle planes and soft tissues, allowing for ample far lateral lumbar decompression, including discectomy and fusion, with a low complication rate.

Objectives To compare the posterolateral Wiltse approach and conventional Midline approach in short lumbosacral fusions in terms of the angle of convergence of pedicle screws. Methods We retrospectively reviewed computed tomography (CT) images of 76 lumbar and sacral pedicular screws that had been placed using a conventional midline approach (CA) (n = 38) and a Wiltse posterolateral approach (WA) (n = 38). All patients underwent short lumbosacral fusions from L3 to S1 for degenerative spinal disease. Screws with a bone gap >4 mm in any direction, cases with previous pedicular implants, and those with coronal plane curves >20° were excluded. Results Considering all implants, the angle of convergence was 23.3° (±15.8). The mean angulation in the WA group was 29.3° (±9.7), whereas in the CA group it was 17.2° (±0.6). This difference was statistically significant (P < 0.05). Conclusions In short, lumbosacral fusion employing the Wiltse approach allowed placement of pedicle implants with more convergence than the conventional midline approach. The clinical relevance of this is unknown, and prospective randomized studies are needed to clarify this.

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) in captive and free-ranging cervids in the USA; its origin is obscure. Archival formalin-fixed and paraffin-embedded specimens of 16 captive mule deer brains with CWD were analyzed using immunocytochemistry for the disease-associated prion protein (PrP). The most prominent pattern of PrP deposition were plaque-like structures, a substantial proportion of which were florid plaques surrounded by a rim of spongiform vacuoles. The percentage of florid plaques was highly variable according to region, ranging from 0% to 52.7%. The highest percentage was observed in the medulla and basal ganglia, the lowest in the cerebral cortex. Only three brains contained no florid plaques. There were also punctate synaptic-type and perivascular deposits, particularly in areas of severe spongiform change, and subpial and subependymal plaque-like deposits, whereas cerebellar involvement was mild. Thus, CWD brain pathology prominently features florid PrP plaques, as does variant Creutzfeldt-Jakob disease (vCJD), but differs in other characteristics from vCJD.

We report here results of modern staining techniques including anti-prion protein (PrP) immunocytochemistry to a set of archival brain specimens of a 16 year-old male who died from kuru in 1967. Brain suspensions transmitted disease to chimpanzees and New World monkeys. The PrP gene is homozygous for valine at the polymorphic codon 129. Histology shows neuronal loss, spongiform change, and astrogliosis. Lesions are maximal in parasagittal and interhemispheric areas of frontal, central and parietal cortex, cingulate cortex, striatum, and thalamus, and are accentuated in middle and deep cerebral cortical layers. PrP accumulates as diffuse synaptic type deposits and mostly unicentric plaques. PrP deposition is maximal in parasagittal and interhemispheric areas of frontal, central and parietal cortex, cingulate cortex, basal ganglia, and cerebellar cortex. Plaques are prominent in the striatum, thalamus, and granular layer of cerebellar cortex. Meticulous examination reveals only rare “florid” plaques with surrounding vacuolation. We conclude that 1) pathology including immunomorphology of PrP deposition in this kuru brain is within the lesion spectrum of Creutzfeldt-Jakob disease although plaques are unusually prominent and widespread; 2) kuru does not share the neuropathological hallmarks of the new Creutzfeldt-Jakob disease variant recently reported in the UK and France; 3) topographic prominence of PrP deposition parallels that of spongiform change and/or astrogliosis.

We have used immunohistochemical techniques and a monoclonal antibody against proliferating cell nuclear antigen (PCNA) to investigate the proliferative activity of glial cells in mice with experimental Creutzfeldt-Jakob disease (CJD), and in human cases of CJD, kuru and Gerstmann-Straussler-Scheinker syndrome (GSS). Only a small proportion of hypertrophic astrocytes showed PCNA immunoreactivity (labelling index, LI: 0–4.5%). PCNA-specific immunostaining was confined entirely to cell nuclei. During the early stages of illness, with minimal CJD pathology, PCNA-immunopositive nuclei were occasionally observed in the subependymal zone of experimentally infected mice. From 18 weeks postinoculation, PCNA-immunopositive astrocytes were most frequently found in the corpus callosum and cerebellar white matter; regions which characteristically exhibit robust vacuolation. No other cells, particularly no cells of microglial morphology, showed PCNA immunoreactivity. In human cases of kuru, CJD and GSS, no PCNA-immunopositive cells were detected despite the presence of numerous microglial cells and reactive hypertrophic astrocytes. These results indicate that only a limited proportion of astrocytes proliferate in the experimental models of subacute spongiform encephalopathies and that microglia are probably postmitotic cells.

Kuru, Creutzfeldt-Jakob disease (CJD) and Gerstmann-Straussler syndrome (GSS) are transmissible dementias affecting humans characterized neuropathologically by intraneuronal vacuolation, spongiform change, astrocytic hypertrophy and hyperplasia and the variable presence of amyloid plaques. It has been suggested that microglia are amyloid-forming cells, which play an essential role in amyloid plaque formation. To study the relationship between microglia and amyloid plaques in kuru, CJD and GSS, cerebellar tissues were examined by the double-immunostaining technique using anti-ferritin antibodies as the microglial marker and anti-scrapie amyloid antibody as plaque marker. Ferritin-immunoreactive microglia were observed interdigitating with and among unicentric, multicentric and diffuse types of scrapie amyloid-immunoreactive plaques and were found to a lesser extent in the neuropil. In kuru and CJD, scrapie amyloid-immunoreactive plaques were predominantly unicentric and were observed in the granular layer. In kuru, 53% of the amyloid plaques were associated with microglia, whereas only 30% of plaques in CJD were. In contrast, scrapie-amyloid-immunoreactive plaques in GSS were of the multicentric type, predominantly observed in the molecular layer, and 90% of these plaques were associated with microglia. Our data indicate that microglia are frequently associated with scrapie amyloid-immunoreactive plaques in GSS, less commonly in kuru and to a much lesser extent in CJD, suggesting that microglia may play a variable but important role in the formation of plaques in the transmissible spongiform encephalopathies.

Neurofibrillary tangles (NFT), one of the neurodegenerative features of Alzheimer's disease, Down's syndrome and normal aging, is a constant, widespread neuropathological finding in Guamanian amyotrophic lateral sclerosis (ALS), parkinsonism-dementia (PD) and in neurologically normal Guamanians, dying of causes other than ALS and PD. NFT in brain tissue sections of patients with Guamanian ALS and PD were immunoreactive to antibodies directed against a 43-amino acid synthetic peptide homologous to amyloid beta/A4-protein (anti-SP43) associated with Alzheimer's disease. NFT extracted from frozen brain tissues of Guamanian patients with ALS and PD and from tissues of neurologically normal Guamanians were congophilic and birefringent. By negative-stain electron microscopy, NFT preparations contained bundles and/or isolated single, straight, unpaired filaments in Guamanian ALS and occasionally pairing of filaments in neurologically normal Guamanians, measuring 5-20 nm in diameter. Formic acid digestion of NFT preparations, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and size-exclusion high-pressure liquid chromatography, showed a protein with an apparent molecular mass of 4- to 4.5-kDa, which by Western blot analysis was immunoreactive to anti-SP43. Immunoabsorption of purified NFT or SP43 with anti-SP43 abolished immunostaining. Our study corroborate previous data that amyloid beta/A4-protein is present in NFT in Guamanian PD. Furthermore, our data indicate that amyloid beta/A4-protein is present in NFT in brain tissues of patients with Guamanian ALS and in neurologically normal Guamanians, suggesting a common mechanism of amyloidogenesis with NFT formation in Alzheimer's disease and normal brain aging.

Chronic wasting disease (CWD), a progressive, fatal neurological disorder of captive mule deer and Rocky Mountain elk, is characterized neuropathologically by spongiform change in the neuropil, intraneuronal vacuolation and astrocytic hypertrophy and hyperplasia. Recently, scrapie amyloid-immunoreactive plaques have been demonstrated in brain tissues of CWD-affected captive mule deer, Rocky Mountain elk and hybrids of captive mule deer and white-tailed deer. We now report on the presence of abnormal fibrils isolated from brain tissues of Rocky Mountain elk using negative-stain electron microscopy. These fibrils resemble those found in scrapie-infected hamster brain. Furthermore, protein bands with relative molecular masses of 26 to 30 kilodaltons were shown to be immunoreactive to antibodies raised against scrapie amyloid by Western immunoblotting. Immuno-dot blot showed similar reactivity. Our data support the clinical and pathological diagnosis of the disease and provide further evidence that CWD belongs to the subacute spongiform encephalopathies.

We have verified, by full open reading frame sequencing, the presence of an amino-acid-altering mutation in codon 102 of the scrapie amyloid protein gene in three affected members of a large and well-documented German family with experimentally transmitted Gerstmann-Straussler-Scheinker syndrome. In addition, we identified the mutation by partial sequencing or DNA restriction enzyme analysis in three of 12 presently healthy family members with an affected parent, and none of 12 members without an affected parent. Thus, a total of six of 15 family members at risk for the disease (including the three established cases) had the same codon 102 mutation, a proportion consistent with the autosomal dominant inheritance pattern of disease expression. It is undetermined whether the mutation influences susceptibility to infection by an exogenous agent or is itself a proximate cause of disease.

We report the immunolocalization of extensive amyloid beta-protein in senile plaques, cerebrovascular amyloid deposits, neurofibrillary tangles and preamyloid in a 32-year-old man with progressive dementia not due to trisomy 21 or trauma. These amyloid deposits were non-reactive to antibodies directed against scrapie amyloid. Our data indicate that the presence of amyloid beta-protein is not limited to normal aging, Alzheimer's disease and related disorders but is also found in younger individuals with progressive dementia.

Chronic wasting disease (CWD), a progressive neurological disorder of captive mule deer, black-tailed deer, hybrids of mule deer and white-tailed deer and Rocky Mountain elk, is characterized neuropathologically by widespread spongiform change of the neuropil, intracytoplasmic vacuolation in neuronal perikarya and astrocytic hypertrophy and hyperplasia. We report the topographic distribution of amyloid plaques reactive to antibodies prepared against scrapie amyloid in CWD-affected captive mule deer (Odocoileus hemionus hemionus). Scrapie amyloid-immunoreactive plaques were found in the cerebral gray and white matter, in deep subcortical nuclei, in isolation or in clusters in areas of vacuolation, and perivascularly, in subpial and subependymal regions. In the cerebellum, immunoreactive amyloid plaques were observed in the molecular, pyramidal and granular layers. Scrapie amyloid-immunoreactive deposits were also seen in neuronal perikarya. Furthermore, amyloid plaques in CWD-affected captive mule deer were alcianophilic at 0.3 M magnesium chloride indicating the presence of weakly to moderately sulfated glycosaminoglycans. Our data corroborate that CWD in captive mule deer belongs to the subacute virus spongiform encephalopathies.

We report the localization of amyloid beta-protein and sulfated glycosaminoglycans in senile plaques and vascular amyloid deposits in brain tissues from patients with Down's syndrome and Alzheimer's disease, and in neurofibrillary tangles of these diseases and those of Guamanian parkinsonism-dementia and amyotrophic lateral sclerosis. We also report the immunolocalization of scrapie amyloid in amyloid plaques containing glycosaminoglycans in kuru, Creutzfeldt-Jakob disease, and Gerstmann-Sträussler's syndrome. Thus, amyloidogenic proteins and sulfated glycosaminoglycans may be copolymerized in amyloid deposits in the nontransmissible and transmissible cerebral amyloidoses.

We report the case of a 73-year-old patient in whom a diagnosis of Creutzfeldt-Jakob disease, suggested by the clinical course, was verified by the neuropathologic finding of widespread spongiform change and astrogliosis, the presence of proteinase-resistant protein in brain extracts, and the experimental transmission of spongiform encephalopathy to primates inoculated with brain tissue. However, neuropathologic examination also revealed a profusion of senile and neuritic plaques and neurofibrillary tangles that reacted with antibody to the amyloid beta-protein characteristic of Alzheimer's disease, but not with antibody to the scrapie amyloid protein characteristic of Creutzfeldt-Jakob disease.

Intracranial tumors associated with Klippel-Feil syndrome usually occur in children, with spinal tumors being more common in adults affected by the syndrome. A rare case of a dermoid cyst at the craniocervical junction presenting as aseptic meningitis in an adult with Klippel-Feil syndrome is described. A review of the literature on tumors associated with this syndrome is also presented.