Prevalence of spine degeneration diagnosis by type, age, gender, and obesity using Medicare data.

Identifying the prevalence of degenerative spinal pathologies and relevant demographic risk factors is important for understanding spine injury risk, prevention, treatment, and outcome, and for distinguishing acute injuries from degenerative pathologies. Prevalence data in the literature are often based on small-scale studies focused on a single type of pathology. This study evaluates the prevalence of diagnosis of selected degenerative spinal pathology diagnoses using Medicare insurance claim data in the context of published smaller-scale studies. In addition, the data are used to evaluate whether the prevalence is affected by age, sex, diagnosed obesity, and the use of medical imaging. The Medicare Claims 5% Limited Data Set was queried to identify diagnoses of degenerative spinal pathologies. Unique patient diagnoses per year were further evaluated as a function of age, gender, and obesity diagnosis. Participants were also stratified by coding for radiological imaging accompanying each diagnosis. The overall prevalence of diagnosed spinal degenerative disease was 27.3% and increased with age. The prevalence of diagnosed disc disease was 2.7 times greater in those with radiology. The results demonstrate that degenerative findings in the spine are common, and, since asymptomatic individuals may not receive a diagnosis of degenerative conditions, this analysis likely underestimates the general prevalence of these conditions.

Clinical assessment and management of Bertolotti Syndrome: a review of the literature.

Bertolotti Syndrome is a diagnosis given to patients experiencing pain caused by the presence of a lumbosacral transitional vertebra (LSTV), which is characterized by enlargement of the L5 transverse process(es), with potential pseudoarticulation or fusion with the sacrum. The Castellvi classification system is commonly utilized to grade LSTVs based on the degree of contact between the L5 transverse process(es) and the sacrum. LSTVs present a diagnostic dilemma to the treating clinician, as they may remain unidentified on plain x-rays and even advanced imaging; additionally, even if the malformation is identified, patients with a LSTV may be asymptomatic or have nonspecific symptoms, such as low back pain with or without radicular symptoms. With low back pain being extremely prevalent in the general population; it can be difficult to implicate the LSTV as the source of this pain. Care should be taken however, to exclude Bertolotti Syndrome in patients under 30 years old presenting with persisting low back pain given its congenital origin. If a LSTV is identified, typically with acquisition of a MRI or CT scan of the lumbosacral spine, and there is an absence of a more compelling or obvious source for the patient's symptoms, a conservative, step-wise management plan is recommended. This may include assessing for improvement in symptoms with injections prior to proceeding with surgical intervention. Additional concerns arise from the biomechanical alterations that a LSTV induces in adjacent spinal levels, predisposing this patient population to a more rapid-onset of adjacent segment disease, raising the question as to the most appropriate surgery (resection of LSTV pseudoarticulation with or without fusion). Postoperative outcome data for patients undergoing surgical treatment is limited in the literature with promising, but variable, results. More large-scale, controlled studies must be performed to gain further insight into the ideal work-up and management of this pathology.

Fulcrum to Generate Maximum Extension of the Spine and Hip-Proposing A New Strategy using EOS Imaging for Patient-specific Assessment of Degenerated Lumbar Spines.

STUDY DESIGN: A retrospective, radiographic comparative study conducted in a single academic institution. OBJECTIVE: This study aims to compare fulcrum extension with conventional extension imaging to determine maximum "hip lordosis" (HL), an important novel patient-specific parameter in spinal realignment surgery, as well as understand the extension capabilities of the lower lumbar spine, which together, are key contributors to whole-body balancing. SUMMARY OF BACKGROUND DATA: Recent literature recognizes the hip as an important contributor to whole-body lordosis beyond a compensator for spinal imbalance. METHODS: Patients >45 years' old with mechanical low back pain due to degenerative spinal conditions were included and grouped based on the imaging performed-fulcrum or conventional extension. All imaging was performed using EOS under standardized instructions and visual aids. Radiographic parameters include global lumbar angle (GLA), inflexion-S1 (Inf-S1) angle, segmental lumbar angles, pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), femoral alignment angle (FAA), HL and spinocoxa angle (SCA). Unpaired t test was used to compare between radiographic parameters. RESULTS: One hundred patients (40 males and 60 females, mean age 63.0 years) underwent either fulcrum or conventional extension EOS® imaging. Both groups had comparable baseline radiographic parameters. Fulcrum extension gave a larger mean GLA (-60.7° vs. -48.5°, P = 0.001), Inf-S1 angle (-58.8° vs. -48.8°, P = 0.003), SCA (-36.5° vs. -24.8°, P < 0.001), L4/5 and L5/S1 lordosis (-20.7° vs. -17.7°, P = 0.041, and -22.3° vs. -17.1°, P = 0.018, respectively), compared to conventional extension. PI, SS, PT, FAA, and HL were similar between both extension postures. CONCLUSION: Fulcrum extension, compared to conventional extension, is better at generating lordosis in the lower lumbar spine, thus improving preoperative assessment of stiffness or instability of the lumbar spine. Both extension methods were equally effective at determining the patient-specific maximum HL to assess the flexibility and compensation occurring at the hip, potentially guiding surgical management of patients with degenerative spines.Level of Evidence: 3.

Vascular imaging of the spine in the US Medicare population: Catheter and MR angiography volumes from 2004 to 2016.

AIMS: The purpose of our study was to analyze utilization trends and physician specialty distribution in spinal catheter angiography and magnetic resonance angiography in the Medicare fee-for-service population. METHODS: Data from the CMS Physician/Supplier Procedure Summary Master Files for 2004 to 2016 were used for this study. The Current Procedural Terminology version 4 codes for spinal magnetic resonance angiography (72159) and spinal catheter angiography (75705) were used to analyze the volumes of these procedures. Using Medicare's 108 specialty code, we compared procedure volumes among physician specialties. Data analysis was performed using SAS version 9.3 for Windows. RESULTS: The volume of spinal catheter angiography performed was 4758 in 2004, peaked at 6869 in 2012, and dropped to 6656 in 2016. Overall, the volume of spinal catheter angiography increased by 40% from 2004 to 2016. Radiologists performed the majority of these procedures (3736 or 56.1%) in 2016, followed by neurosurgeons (2456 or 36.9%), and neurologists (346 or 5.2%). The spinal magnetic resonance angiography volume fluctuated between 0 and 1 from 2004 to 2009, then precipitously increased to 40 in 2010, peaked at 133 in 2011, and declined to 81 in 2016. The volume of spinal magnetic resonance angiography procedures increased by 8000% from 2004 to 2016, with radiologists performing the majority of them. CONCLUSION: Our results show that spinal catheter angiography volumes continue to rise in the Medicare fee-for-service population, and are largely performed by radiologists, neurosurgeons, and neurologists. Although spinal magnetic resonance angiography volumes have started to increase, they comprise only a small fraction of studies performed for vascular evaluation of the spine.

Assessment of Construct Validity of the Oswestry Disability Index and the Scoliosis Research Society-30 Questionnaire (SRS-30) in Patients With Degenerative Spinal Disease.

STUDY DESIGN: Observational cohort study. OBJECTIVES: To measure and compare the structural validity of the Oswestry Disability Index (ODI) and the Scoliosis Research Society-30 (SRS-30) questionnaire in an adult population with prolonged degenerative thoracolumbar disease. SUMMARY OF BACKGROUND DATA: The ODI and the SRS-30 are commonly used patient-reported outcome instruments to assess back-specific disability and symptoms related to scoliosis. Still, these instruments have not been validated for degenerative spinal disease with different stages of deformity. METHODS: Altogether, 637 consecutive adult patients with degenerative spinal pathologies were included. The patients completed the ODI (version 2.0), the 23 preoperative items of the SRS-30, a general health survey, the Kasari Frequency Intensity Time (FIT) index, the Depression Scale (DEPS), the RAND-36, and visual analog scales for leg and back pain instruments. Psychometric statistical and illustrative analyses were conducted. Deformity groups were analyzed to assess how well the two instruments reflect deformity-related back problems. RESULTS: Both instruments reflected good coverage and targeting. Correlation between the ODI and the SRS-30 was high (r = 0.70; p < .001). Both measures could distinguish between different general health states. The SRS-30 strongly reflected mental state and social well-being. The SRS-30 was less sensitive for pain and function. Furthermore, the principal component of pain/function explained more variance in the SRS-30 compared with the ODI score. The ODI was more sensitive for variance of disability among different age and deformity groups. CONCLUSIONS: Both the ODI and the the SRS-30 provide valid scores in evaluating health-related quality of life and/or level of disability among patients with prolonged degenerative thoracolumbar disease. The ODI has slightly higher correlation with physical functioning. The SRS-30 seems to be better when evaluating the emotional and psychological functions. LEVEL OF EVIDENCE: Level III.

Evaluation criteria for the assessment of occupational diseases of the lumbar spine - how reliable are they?

BACKGROUND: In 2005, the German Association of Occupational Accident Insurance Funds (DGUV) defined radiological evaluation criteria for the assessment of degenerative occupational diseases of the lumbar spine. These include the measurement of intervertebral osteochondrosis and classification of vertebral osteosclerosis, antero-lateral and posterior spondylosis, and spondyloarthritis via plain radiography. The measures currently remain in daily use for determining worker compensation among those with occupational diseases. Here, we aimed to evaluate the inter- and intra-observer reliability of these evaluation criteria. METHODS: We enrolled 100 patients with occupational degenerative diseases of the lumbar spine. Native antero-posterior and lateral radiographs of these patients were evaluated according to DGUV recommendations by 4 observers with different levels of clinical training. Evaluations were again conducted after 2 months to assess the intra-observer reliability. RESULTS: The measurement of intervertebral osteochondrosis showed good inter-observer reliability (ICC: 0.755) and excellent intra-observer reliability (ICC: 0.827). The classification of vertebral osteosclerosis exhibited moderate kappa values for inter-observer reliability (К: 0.426) and intra-observer reliability (К: 0.441); the remaining 3 criteria showed poor inter- and intra-observer reliabilities. CONCLUSION: The measurement of intervertebral osteochondrosis and classification of vertebral osteosclerosis showed adequate inter- and intra-observer reliability in the assessment of occupational diseases of the lumbar spine, whereas the classification of antero-lateral and posterior spondylosis and spondyloarthritis stage exhibited insufficient reliability. Hence, we recommend the revision of the DGUV recommendations for the evaluation of occupational diseases of the lumbar spine.

Assessment of T1 Slope Minus Cervical Lordosis and C2-7 Sagittal Vertical Axis Criteria of a Cervical Spine Deformity Classification System Using Long-Term Follow-up Data After Multilevel Posterior Cervical Fusion Surgery.

BACKGOUND: Recently, previous research proposed a cervical spine deformity (CSD) classification using a modified Delphi approach. However, C2-C7 sagittal vertical axis (SVA) and T1 slope minus C2-C7 lordosis (TS-CL) cut-off values for moderate and severe disability were based on expert opinion. OBJECTIVE: To investigate the validity of a CSD classification system. METHODS: From 2007 to 2012, 30 consecutive patients with a minimum 5-yr follow-up having 3- or more level posterior cervical fusion met inclusion criteria. The following radiographic parameters were measured: C0-C2 lordosis, C2-C7 lordosis, C2-C7 SVA, T1 slope, and TS-CL. Pearson correlation coefficients were calculated between pairs of radiographic measures and health-related quality of life. RESULTS: Average follow-up period was 7.3 yr. C2-C7 SVA positively correlated with neck disability index (NDI) scores (r = 0.554). Regression models predicted a threshold C2-C7 SVA value of 40.8 mm and 70.6 mm correlated with moderate and severe disability based on the NDI score, respectively. The TS-CL had positive correlation with C2-C7 SVA and NDI scores (r = 0.841 and r = 0.625, respectively). Regression analyses revealed that a C2-C7 SVA value of 40 mm and 70 mm corresponded to a TS-CL value of 20° and 25°, respectively. CONCLUSION: Regression models predicted a threshold C2-C7 SVA (value of 40.8 mm and 70.6 mm) and TS-CL (value of 20° and 25°) correlated with moderate and severe disability based on the NDI, respectively. The cut-off value C2-C7 SVA and TS-CL modifier of the CSD classification can be revised accordingly.

Preoperative Assessment of Bone Quality in Spine Deformity Surgery: Correlation With Clinical Practice and Published Recommendations.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The goals of this study were to (A) evaluate preoperative bone quality assessment and intervention practice over time and (B) review the current evidence for bone evaluation in spine fusion surgery. SUMMARY OF BACKGROUND DATA: Deformity spine surgery has demonstrated improved quality of life in patients; however, its cost has made it controversial. If preoperative bone quality can be optimized then potentially these treatments could be more durable; however, at present, no clinical practice guidelines have been published by professional spine surgical organizations. METHODS: A retrospective cohort review was performed on patients who underwent a minimum five-level primary or revision fusion. Preoperative bone quality metrics were evaluated over time from 2012 to 2017 to find potential trends. Subgroup analysis was conducted based on age, sex, preoperative diagnosis, and spine fusion region. RESULTS: Patient characteristics including preoperative rates of pseudarthrosis and junctional failure did not change. An increasing trend of physician bone health documentation was noted (P = 0.045) but changes in other metrics were not significant. A sex bias favored females who had higher rates of preoperative DXA studies (P = 0.001), Vitamin D 25-OH serum labs (P = 0.005), Vitamin D supplementation (P = 0.022), calcium supplementation (P < 0.001), antiresorptive therapy (P = 0.016), and surgeon clinical documentation of bone health (P = 0.008) compared with men. CONCLUSION: Our spine surgeons have increased documentation of bone health discussions but this has not affected bone quality interventions. A discrepancy exists favoring females over males in nearly all preoperative bone quality assessment metrics. Preoperative vitamin D level and BMD assessment should be considered in patients undergoing long fusion constructs; however, the data for bone anabolic and resorptive agents have less support. Clinical practice guidelines on preoperative bone quality assessment spine patients should be defined. LEVEL OF EVIDENCE: 4.

Interobserver Reliability of Spinal Adverse Events Severity System - Neuro (SAVES-N): A Prospective Adverse Event Reporting System for Neurosurgical Cases.

BACKGROUND: The reporting of adverse events (AEs) in neurosurgery uses inconsistent definitions and subjective grading systems. A standardized system for recording and describing AEs would allow valid comparisons to be drawn between different institutions, using different technologies, at different times. The Spinal Adverse Events Severity System - Neuro (SAVES-N) system is a modification of the well-validated SAVES-V2 system that encompasses complications from both cranial and spinal surgery. The objective of this study was to assess the interobserver reliability of SAVES-N in spinal and cranial neurosurgery. METHODS: Ten vignettes, including cranial and spinal neurosurgical cases, were assessed by groups of consultant neurosurgeons (n = 5) and neurosurgical registrars (n = 5) using the SAVES-N system. Interobserver reliability for the presence of AEs, the type of AE, and the SAVES severity grade of the AE were calculated using Gwet's AC2 and Fleiss' kappa and were interpreted using the thresholds described by Landis and Koch. RESULTS: Neurosurgeons had almost-perfect agreement (Gwet AC2 = 0.93), whereas registrars had substantial agreement (Gwet's AC2 = 0.74) in determining the presence or absence of AEs. Both neurosurgeons (Fleiss' kappa = 0.78) and registrars (Fleiss' kappa = 0.70) demonstrated substantial agreement within their groups as to the type of AE. Similarly, neurosurgeons (Gwet's AC2 = 0.94) and registrars (Gwet's AC2 = 0.81) both graded the severity of the AE with almost perfect agreement. CONCLUSIONS: The results of this study demonstrate that the scope of the well-validated SAVES-V2 system may be broadened to cranial neurosurgical cases by SAVES-N with substantial to almost-perfect interobserver reliability.

Real-time Ultrasound Assessment of Astronaut Spinal Anatomy and Disorders on the International Space Station.

OBJECTIVES: Back pain is one of the most common conditions of astronauts during spaceflight and is hypothesized to be attributed to pathologic anatomic changes. Ultrasound (US) represents the only available imaging modality on the International Space Station, but a formal US protocol for imaging the structures of the spinal column does not exist. This investigation developed a method of acquiring diagnostic-quality images of the anterior lumbar and cervical regions of the spine during long-duration spaceflight. METHODS: Comprehensive spinal US examinations were conducted on 7 long-duration spaceflight astronauts before flight, in flight, and after flight and compared to preflight and postflight magnetic resonance imaging data. In-flight scans were conducted after just-in-time training assisted by remote expert tele-US guidance. RESULTS: Novice users were able to obtain diagnostic-quality spinal images with a 92.5% success rate. Thirty-three anomalous or pathologic findings were identified during the preflight US analysis, and at least 14 new findings or progressions were identified during the postflight US analysis. Common findings included disk desiccation, osteophytes, and qualitative changes in the intervertebral disk height and angle. CONCLUSIONS: Ultrasound has proven efficacy as a portable and versatile diagnostic imaging modality under austere conditions. We demonstrated a potential role for US to evaluate spinal integrity and alterations in the extreme environment of space on the International Space Station. Further investigations should be performed to corroborate this imaging technique and to create a larger database related to in-flight spinal conditions during long-duration spaceflight.

Estimating the arterial input function from dynamic contrast-enhanced MRI data with compensation for flow enhancement (II): Applications in spine diagnostics and assessment of crohn's disease.

BACKGROUND: Pharmacokinetic (PK) models can describe microvascular density and integrity. An essential component of PK models is the arterial input function (AIF) representing the time-dependent concentration of contrast agent (CA) in the blood plasma supplied to a tissue. PURPOSE/HYPOTHESIS: To evaluate a novel method for subject-specific AIF estimation that takes inflow effects into account. STUDY TYPE: Retrospective study. SUBJECTS: Thirteen clinical patients referred for spine-related complaints; 21 patients from a study into luminal Crohn's disease with known Crohn's Disease Endoscopic Index of Severity (CDEIS). FIELD STRENGTH/SEQUENCE: Dynamic fast spoiled gradient echo (FSPGR) at 3T. ASSESSMENT: A population-averaged AIF, AIFs derived from distally placed regions of interest (ROIs), and the new AIF method were applied. Tofts' PK model parameters (including vp and Ktrans ) obtained with the three AIFs were compared. In the Crohn's patients Ktrans was correlated to CDEIS. STATISTICAL TESTS: The median values of the PK model parameters from the three methods were compared using a Mann-Whitney U-test. The associated variances were statistically assessed by the Brown-Forsythe test. Spearman's rank correlation coefficient was computed to test the correlation of Ktrans to CDEIS. RESULTS: The median vp was significantly larger when using the distal ROI approach, compared to the two other methods (P < 0.05 for both comparisons, in both applications). Also, the variances in vp were significantly larger with the ROI approach (P < 0.05 for all comparisons). In the Crohn's disease study, the estimated Ktrans parameter correlated better with the CDEIS (r = 0.733, P < 0.001) when the proposed AIF was used, compared to AIFs from the distal ROI method (r = 0.429, P = 0.067) or the population-averaged AIF (r = 0.567, P = 0.011). DATA CONCLUSION: The proposed method yielded realistic PK model parameters and improved the correlation of the Ktrans parameter with CDEIS, compared to existing approaches. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2018;47:1197-1204.

Prenatal Assessment of the Position of Fetal Conus Medullaris as a Predictor of Fetal Spinal Lesions.

OBJECTIVES: The aim of this study is to compare two different methods in assessment of the position of fetal conus medullaris (CM) and to explore the significance for assessment of CM. METHODS: This study included both normal fetuses and those with the diagnosis of fetal spinal lesions. The position of fetal CM was performed sonographically using two methods: location of CM in relation to the vertebral body (CM level) and measurement of the conus sacrum (CS) distance. RESULTS: The results showed that intra-observer and interobserver concordance was high for the two methods, both in the normal and abnormal groups. There was significant association between femur length and CS distance (R2 = 0.917) and between gestational age and CS distance (R2 = 0.892). CONCLUSIONS: We propose the combined use of CM level location and CS distance measurement for the prenatal diagnosis of fetal spinal lesions for complementary needs.

Apparent diffusion coefficient maps in the assessment of surgical patients with lumbar spine degeneration.

PURPOSE: To assess the utility of apparent diffusion coefficient (ADC) maps for the assessment of patients with advanced degenerative lumbar spine disease and describe characteristic features of ADC maps in various degenerative lumbar spinal conditions. METHODS: T1-weighted, T2-weighted and diffusion weighted (DWI) MR images of 100 consecutive patients admitted to the spinal surgery service were assessed. ADC maps were generated from DWI images using Osyrix software. The ADC values and characteristic ADC maps were assessed in the regions of interest over the different pathological entities of the lumbar spine. RESULTS: The study included 452 lumbar vertebral segments available for analysis of ADCs. Characteristic ADC map features were identified for protrusion, extrusion and sequester types of lumbar disk herniations, spondylolisthesis, reactive Modic endplate changes, Pfirrmann grades of IVD degeneration, and compromised spinal nerves. Compromised nerve roots had significantly higher mean ADC values than adjacent (p < 0.001), contralateral (p < 0.001) or adjacent contralateral (p < 0.001) nerve roots. Compared to the normal bone marrow, Modic I changes showed higher ADC values (p = 0.01) and Modic 2 changes showed lower ADC values (p = 0.02) respectively. ADC values correlated with the Pfirrmann grading, however differed from herniated and non-herniated disks of the matched Pfirrmann 3 and 4 grades. CONCLUSION: Quantitative and qualitative evaluation of ADC mapping may provide additional useful information regarding the fluid dynamics of the degenerated spine and may complement standard MRI imaging protocol for the comprehensive assessment of surgical patients with lumbar spine pathology. ADC maps were advantageous in differentiating reactive bone marrow changes, and more precise assessment of the disk degeneration state. ADC mapping of compressed nerve roots showed promise but requires further investigation on a larger cohort of patients.

Reuse and reduce: abdominal CT, lumbar spine MRI, and a potential 1.2 to 3.4 billion dollars in cost savings.

PURPOSE: To determine how much money could potentially be saved by re-evaluating a patient's prior recent abdominal CT for lumbar spine pathology instead of ordering a lumbar spine MRI. METHODS: Abdominal CT studies, from all consecutive patients who had an abdominal CT within 12 months prior to a lumbar spine MRI obtained between 11/1/15 and 5/30/16, were retrospectively reviewed in a blinded fashion for the presence of any significant lumbar spine abnormalities. CT studies that accurately reflected all normal and abnormal findings when compared to the standard of reference, the prospectively interpreted lumbar spine MR imaging reports, were used to indicate which lumbar spine MRI studies potentially could have been avoided and to calculate the potential cost savings. RESULTS: Of the 81 abdominal CT studies that met the inclusion criteria of this study, 62% (50/81) were TP, 28% (23/81) were TN, 5% (4/81) were FP, and 5% (4/81) were FN studies. 90% (73/81) of the lumbar spine MRI studies could potentially have been avoided during the 7 months of this study. The predicted savings by reviewing the abdominal CT for lumbar spine abnormalities prior to ordering a lumbar spine MRI are an estimated 1.2-3.4 billion dollars per year. CONCLUSION: Recent abdominal CT studies should be reviewed for lumbar spine pathology prior to a patient undergoing lumbar spine MRI. Avoiding unnecessary lumbar spine MRI studies could potentially save the U.S. healthcare system an estimated 1.2-3.4 billion dollars per year.

An Assessment of the Medial Angle of Inserted Subaxial Cervical Pedicle Screw during Surgery: Practical Use of Preoperative CT Scanning and Intraoperative X-rays.

The most important factor for cervical pedicle screw placement (CPS) is creating a sufficient medial angle. We aimed to know the medial angle of the inserted subaxial CPS during surgery using intraoperative AP X-rays. From March 2012 to September 2014, we performed posterior cervical fusions using CPS on 75 patients, including a total of 389 CPS insertions. Using preoperative CT scanning, we determined the θlat (i.e., an angle between a vertical line and a line to connect the planned entry point and the axial middle point of the pedicle) and θmed (i.e., an angle between a vertical line and a line to connect a new medial entry point and the axial middle point of the pedicle; this angle was regarded as minimally acceptable and a safe medial angle). The actual inserted medial angle (θins) was checked and we determined whether it was between the θmed and θlat in the accurately placed CPS, and not in the laterally violated CPS. We measured the horizontal distance of the CPS body (l; using an intraoperative AP X-ray). If the actual screw length (L) was known, we could calculate the medial angle (θAP) as sin-1 l / L. We checked the θAP and θins for all of the same levels. Intra- and inter-observer agreement was analyzed. Among 368 accurately inserted CPSs, we found that 360 of the θins values were greater than or equal to the θmed on the same level (P <0.001). The intra-observer agreements were 0.781 and 0.847. The inter-observer agreements were 0.917 and 0.949. It was important that θins was greater than or equal to the θmed. Our suggested formula, θAP = sin-1 l / L, seems to be useful for predicting the medial angle of the inserted CPS and for comparing it with θmed during surgery based on an AP X-ray and preoperative CT scan.

Modified Mini-open Transforaminal Lumbar Interbody Fusion: Description of Surgical Technique and Assessment of Free-hand Pedicle Screw Insertion.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To describe a modified technique for mini-open transforaminal lumbar interbody fusion (TLIF) that improves visualization for decompression, fusion, and freehand pedicle screw insertion. Accuracy of freehand pedicle screw placement with this technique was assessed. SUMMARY OF BACKGROUND DATA: Mini-open TLIF is a minimally invasive technique that allows limited visualization of the bone and neural anatomy via an expandable tubular retractor inserted through the Wiltse plane. No significant modification that of this technique has been described in detail. METHODS: In this study, 92 consecutive patients underwent one-level modified mini-open TLIF (MOTLIF). MOTLIF modifications consisted of (i) transmuscular dissection through the multifidus muscle rather than intermuscular dissection in the Wiltse plane; (ii) microsurgical detachment of multifidus from the facet rather than muscle dilation; (iii) en bloc total facetectomy (unilateral or bilateral, as needed for decompression); (iv) facet autograft used for interbody fusion; and (v) solid pedicle screws placed bilaterally by a freehand technique under direct vision. RESULTS: The mean age was 53 years. Mean follow-up was 35 months (minimum 2 yrs). By 6 months, mean Visual Analog Scale for back and leg pain had improved from 51 to 19 and from 58 to 17, respectively, and mean Oswestry Disability Index (ODI) improved from 53 to 16. These improvements persisted at 2 years. Solid fusion, defined by computed tomography at 1 year, was achieved in 88.1%, whereas satisfactory fusion was achieved in 95.2% of patients. Pedicle screws were accurately placed in 335 of 336 imaged pedicles (pedicle breach grades: 91.1% grade 1; 8.6% grade 2; and 0.3% grade 3). Mean fluoroscopy time was 29.3 seconds. CONCLUSION: MOTLIF is a safe and effective minimally invasive technique with a high fusion rate. It allows accurate pedicle screw placement by a freehand technique. By eliminating bi-planar fluoroscopy, it helps reduce radiation exposure. This is the largest published report of mini-open TLIF to date. LEVEL OF EVIDENCE: 4.

Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Interpretation Criteria for Assessment of Antibiotic Treatment Response in Pyogenic Spine Infection.

PURPOSE: The objective of the study was to determine if fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) can assess the response of patients with pyogenic spine infection to antibiotic treatment in a clinically useful time frame. METHODS: Twenty-eight patients with suspected pyogenic spine infection had baseline (18)F-FDG PET/CT. Patients with proven or probable infection were divided into good and poor responders to antibiotic therapy based on clinical criteria. These patients had a follow-up (18)F-FDG PET/CT 6-8 weeks later. RESULTS: Six of 28 patients were deemed negative for infection based on (18)F-FDG PET/CT. Two patients were excluded because of discrepancies in interpretation. Of the 20 patients deemed positive for infection, 13 had a pathogen isolated and all showed (18)F-FDG uptake in bone and/or soft tissue at baseline. Patients with a poor clinical response to treatment had persistent (18)F-FDG uptake in bone and/or soft tissue on follow-up. Patients with good clinical response had uptake confined to the margins of the destroyed disc. None of these patients had recurrent infection, even if antibiotics had already been discontinued at the time of the follow-up scan. CONCLUSIONS: (18)F-FDG uptake confined to the margins of a destroyed disc after antibiotic therapy of pyogenic spine infection must not be considered indicative of persistent infection and likely represents mechanically induced inflammation. (18)F-FDG uptake in bone or soft tissue does indicate active infection. Quantification of activity could not reliably differentiate patients with active infection from those without active infection and those who had had a successful response to therapy. The pattern of activity is critical to accurate interpretation.

Assessment of pedicle screw placement accuracy in thoracolumbosacral spine using freehand technique aided by lateral fluoroscopy: results of postoperative computed tomography in 114 patients.

BACKGROUND CONTEXT: Pedicle screw fixation is currently widely used in spine surgery for various pathologies. Increasing screw placement accuracy would improve the outcomes. PURPOSE: To determine the accuracy rate of screw placement in a group of patients who underwent pedicle screw fixation with conventional techniques. STUDY DESIGN: A case series. PATIENT SAMPLE: It includes patients undergoing posterior spinal fixation with pedicle screw insertion. Outcome measures include the accuracy of screw placement in pedicles defined by postoperative computed tomography (CT). METHODS: After surgery, an axial thin-cut CT scan was performed in all patients. Screw position was classified as correct when the screw was completely surrounded by the pedicle cortex and incorrect when any part of the screw was outside the pedicle boundaries. RESULTS: Seven hundred seventy screws were inserted at vertebral levels T7-S1 of 114 patients between March 2012 and December 2012. There were three wound infections and one death. Eighteen screws were diagnosed as having an incorrect position (2.3%). The highest accuracy was observed in levels L4 and L5 (0.8% inaccuracy rate for each), whereas the highest inaccuracy rate was observed in T9. The mean inaccuracy rate was 10.5% for levels T7-T9, 3.5% for levels T10-L2, and 0.9% for levels L3-S1. The differences were statistically significant. Only one screw (5%) needed revision. CONCLUSIONS: The results of our study show that conventional methods for pedicle screw placement remain safe and accurate, with best results obtained in the lumbosacral spine, followed by the thoracolumbar junction. Nonetheless, results are less accurate in the midthoracic spine.