Body Of L5 Research Articles

Bone Marrow Adipose Tissue Is Increased in Postmenopausal Women With Postsurgical Hypoparathyroidism.

Suppression of bone turnover, greater trabecular volume, and normal-high normal all-site bone mineral density (BMD) are hallmarks of postsurgical hypoparathyroidism (HypoPT). Impairment in the trabecular microarchitecture with possible higher risk of vertebral fractures (VF) in women with postmenopausal HypoPT has also been described. Currently, no data on bone marrow adipose tissue (BMAT) are available in HypoPT. To assess BMAT by magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H-MRS) in postmenopausal women with chronic postsurgical HypoPT. This cross-sectional pilot study, conducted at an ambulatory referral center, included 29 postmenopausal women (mean age 66 ± 8.4 years) with postsurgical HypoPT and 31 healthy postmenopausal women (mean age 63 ± 8.5). Lumbar spine MRI was performed and BMAT was measured by applying PRESS sequences on the L3 body. Lumbar spine, femoral neck, and total hip BMD were measured by dual x-ray absorptiometry (DXA); site-matched spine trabecular bone score (TBS) was calculated by TBS iNsight (Medimaps, Switzerland); VF assessment was performed with lateral thoracic and lumbar spine DXA. Fat content (FC) and saturation level (SL%) were higher (P <.0001 and P <.001), while water content (W) was lower in HypoPT compared to controls (P <.0001). FC significantly correlated with years since menopause and body weight (P <.05) in HypoPT, while TBS negatively correlated with FC and SL% (P <.05) and positively with residual lipids (RL) and W (P <.05). We demonstrate for the first time that BMAT is increased in postmenopausal women with postsurgical hypoparathyroidism and negatively associated with trabecular microarchitecture.

Trabecular bone score, bone marrow fat and vertebral fractures in cushing syndrome.

Prediction of fragility fractures in Cushing syndrome (CS) is a challenge since dual energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) does not capture all the alterations in bone microstructure induced by glucocorticoid excess. In this study we investigated the relationship between trabecular bone score (TBS), bone marrow fat (BMF) and vertebral fractures (VFs) in endogenous CS. Cross-sectional. Thirty subjects (7 M and 23 F, mean age 44.8 ± 13.4 yrs, range: 25-71) with active hypercortisolism were evaluated for VFs by quantitative morphometry, BMD and TBS by lumbar spine DXA and BMF by single-voxel magnetic resonance spectroscopy of vertebral body of L3. Subjects with VFs (17 cases; 56.7%) had higher BMF (P = 0.014) and lower BMD T-score (P = 0.012) and TBS (P = 0.004) as compared to those without VFs. Prevalence of VFs resulted to be significantly higher in individuals with impaired TBS as compared to those with normal TBS (77.8% vs. 25.0%; P = 0.008). Among patients with VFs, only 6 (35.3%) had either osteoporosis or "low BMD for age". In logistic regression analysis, impaired TBS maintained the significant association with VFs [odds ratio (OR) 6.60, 95% C.I. 1.07-40.61; P = 0.042] independently of BMF (OR 1.03, 95% C.I. 0.99-1.08; P = 0.152). TBS might be more accurate than BMF in identifying subjects with active CS and skeletal fragility at risk of VFs. Excess in glucocorticoids is associated with alterations in bone remodeling and metabolism, leading to fragility fractures regardless of bone mineral density, making more challenging for the clinician the identification of high-risk population and the definition of preventing strategies. In this context, instrumental parameters suggestive of bone quality alterations and predictive of increased fracture risk are needed. In this study, we found CS patients to have bone quality alterations as indicated by the decreased trabecular bone score and increased bone marrow fat, as measured by DEXA and MRI respectively. Both parameters were associated with high risk of VFs, and were inversely correlated, although TBS seems to be more accurate than BMF in fractures prediction in this clinical setting.

Paraspinal muscles atrophy on both sides and at multiple levels after unilateral lumbar partial discectomy.

To identify the changes in cross-sectional areas (CSAs) and fatty infiltration of both sides of the paravertebral muscles and their associations with prognostic factors in patients who underwent unilateral lumbar discectomy. We retrospectively reviewed 27 patients who underwent magnetic resonance imaging before and after 1- or 2-level lumbar discectomy. The CSAs and functional cross-sectional areas of the paraspinal muscles were bilaterally measured from L1 to L2 to L5 to S1 based on T2-weighted axial images. These parameters were compared pre-and postoperatively. CSAs and functional cross-sectional areas decreased also in non-operative, non-surgical levels, not only in operated levels after discectomy. In the correlation analysis, the CSA of psoas major muscle at L1 to L2 was significantly decreased in patients with lower preoperative lordosis (r = 0.598, P = .040). The postoperative CSA of psoas major muscle at L4 to L5 was lower in those with the higher Pfirrmann grade (r = -0.590, P = .002); however, the CSA of quadratus lumborum muscle at L1 to L2 showed the opposite result (r = 0.526, P = .036). Similar results were also observed in the partial correlation adjusted for age and postoperative duration. Patients who underwent discectomy experienced overall paraspinal muscle atrophy in the lumbar region, including surgical and non-surgical sites. Such atrophic changes emphasized the need for core strengthening and lumbar rehabilitation from the early period after partial discectomy.

Estimation of Spleen Volume Using MRI Segmentation: Would One Slice Be Enough?

This study aimed to establish spleen volume in adult Sudanese using manual segmentation and the Cavalieri method with magnetic resonance images (MRI). A total of 345 abdominal MRI scans for adults were retrospectively studied for patients who underwent abdomen MRI between September to October 2016. The data were collected from two scanning centers in Khartoum, Sudan. For each series of sectional images, the spleen was manually segmented, and the volume was calculated using matrix laboratory (MATLAB) code. Furthermore, abdominal circumferences and diameters, in addition to L1 body dimension and spinal canal, were measured. The mean splenic volume in our study was 187.2cm3, without a significant change with age (P = 0.269). The average volume in males was 223.5cm3while in females it was 170.27cm3. The average coefficient error (CE) was 0.029. A positive significant correlation was found between the volume and spleen length (beta standardized coefficient = 0.781, P < 0.05). The mean length was 9.18cm. Additionally, our data showed an insignificant correlation between the volume and the other measurements, except for the abdomen transverse diameter (beta standardized coefficient = 0.267, P < 0.05). The results of our study coincided with previous studies in the normal range of spleen volume and the strong correlation with length, regardless of the irregular shape of the spleen. In addition, manual segmentation was a reliable method to measure spleen volume objectively. However, our single-slice measurements were insufficient.

A Dual-Selective Channel Attention Network for Osteoporosis Prediction in Computed Tomography Images of Lumbar Spine

Osteoporosis is a common systemic bone disease with insidious onset and low treatment efficiency. Once it occurs, it will increase bone fragility and lead to fractures. Computed tomography (CT) is a non-invasive medical examination method that can identify the bone condition of patients. In this paper, we propose a novel channel attention module, which is subsequently integrated into the supervised deep convolutional neural network (DCNN) termed DSNet, which can perform feature fusion from two different scales, and use the method of quadratic weight calculation to enhance the interconnection among feature map channels and improve the detection and classification performance for the bone condition in lumbar spine CT images. To train and test the proposed framework, we retrospectively collect 4805 CT images of 133 patients, using DXA as the gold standard. According to the T-value diagnostic criteria defined by WHO, the vertebral bodies of L1 - L4 in CT images are labeled and classified into osteoporosis, osteopenia and normal bone mineral density. Meanwhile, the training set and test set are constructed in the ratio of 4:1. As a result, the DSNet achieves a prediction accuracy of 83.4% and a recall rate of 90.0% on the test set, indicating that the proposed model has the potential to assist clinicians in diagnosing individuals with abnormal BMD and may alert patients at high risk of osteoporosis for timely treatment.

Concentration of Selected Macronutrients and Toxic Elements in the Blood in Relation to Pain Severity and Hydrogen Magnetic Resonance Spectroscopy in People with Osteoarthritis of the Spine.

Macronutrients and toxic elements may play an important role in the pathogenesis of osteoarthritis of the spine. The objective of this study was to evaluate the relationship between the concentrations of Ca, Mg, Pb, Cd and Hg in blood with the results of hydrogen magnetic resonance spectroscopy and the severity of pain. Patients with osteoarthritis of the spine (n = 90) and control subjects (n = 40) were studied. The concentrations of mineral components in blood were determined by atomic absorption spectrometry (ASA). Spinal pain severity was assessed using the Visual Analog Scale (VAS). Hydrogen magnetic resonance spectroscopy (1H-MRS) was used to determine the fat/water ratio in the bodies of L1, L5 and the L4/5 intervertebral disc. The median concentration of Mg in the serum of subjects with spinal degenerative disease was significantly lower (p < 0.001) than that in healthy subjects. The median concentration of Cd in the blood of subjects with osteoarthritis of the spine was significantly higher (p < 0.05) than that in the control group. Significantly lower (p < 0.05) median molar ratios of Ca to Cd and Pb as well as Mg to Pb and Cd were observed among patients with osteoarthritis of the spine. Significant differences (p < 0.05) were observed in the value of the fat/water ratio in selected spinal structures, depending on normal or abnormal serum Ca and Mg concentrations. The study showed some abnormal macronutrient concentrations, as well as disturbed ratios of beneficial elements to toxic elements in the blood of people with osteoarthritis of the spine.

Ultrasonographic assessment of the renal size using a kidney length to vertebral body length ratio in cats.

Ultrasonographic assessment of the renal size can provide useful clinical information, in combination with other ultrasonographic parameters. The aims of this study were to establish the agreement between the ultrasonographic and radiographic measurements of the kidneys (K) and vertebral bodies (L5 and L6), to establish an ultrasonographic measurement of kidney-to-vertebral body (L5 and L6) ratio to estimate the renal size in cats, and to assess the impact of age, body weight, sex, and gonadal status on the ultrasonographic measurements of the kidneys, vertebral bodies, and ratios. The vertebral bodies of L5 and L6 were chosen as they were easy to identify with ultrasonography (US) using the lumbosacral junction as a landmark, and they are not usually affected by vertebral anomalies. A total of 60 cats (19 intact males, 12 neutered males, 17 intact females, and 12 neutered females) were included in the study. The cats were divided into three age groups (<7 months, 7 months−7 years, and >7 years), two body weight categories (≤ 3.5 kg and >3.5 kg), and two sex and gonadal status groups (male and female, and intact and neutered, respectively). Measurements of the renal and vertebral body length were performed on the radiographic and ultrasonographic images. Two different ratios were obtained, namely, K/L5 and K/L6. There was no significant difference between the length of both kidneys and the length of the vertebral bodies of L5 and L6 on ultrasonographic or radiographic images. There was a good agreement between ultrasonographic and radiographic measurements of both kidneys and vertebral bodies. In conclusion, the kidney length to L6 length ratio obtained was 1.81 ± 0.20 (1.76–1.86), which was useful for evaluating the size of the feline kidney and was not influenced by the age, body weight, sex, or gonadal status.

A Case of Acute Traumatic Dissection of the Infra-Renal Abdominal Aorta

The successful management of patients with blunt abdominal trauma depends on early diagnosis and therapy. We present the case of a 64-year-old man involved in a fall with blunt abdominal trauma. Initial computed tomography (CT) showed a dissection of the infra renal aorta associated with aneurysmal dilation, comminuted compression fractures of the vertebral bodies of D2 and D3, sequelae of anterior compression fracture of the vertebral body of L2 and multiple rib fractures, simple and displaced without fail chest. Chronicity of the dissection was successfully obtained by only medical management, and after 6 days the patient was able to leave our department in good general condition. We present a case of acute of the infra- renal aorta and its successful management with conservative traumatic dissection treatment.

What happens at the L5/S1 facet joint when implants are placed across the sacroiliac joint?

BackgroundInjuries to the posterior pelvic ring are often stabilized with fixation across the sacroiliac joint (SIJ). However, the compensatory changes at the neighboring L5/S1 facet joint are unknown. The objective of this study was to determine the compensatory change in pelvic kinematics and contact forces at the L5/S1 facet joint after fixation across the sacroiliac joint (SIJ) using a cadaveric model. MethodsFive fresh-frozen cadaveric pelvis specimens were dissected to remove non-structural soft tissue. Retroreflective markers were fixed to the L5 body, S1 body and bilateral anterior superior iliac spines to represent the motion of L5, S1 and the ileum, respectively. Pressure sensors were inserted in both L5/S1 facet joints. Testing was performed using a robotic system that applied load to mimic ambulation. Testing was performed prior to SIJ fixation, after unilateral SIJ fixation and bilateral fixation. ResultsContact force at the L5/S1 facet joint significantly increased by 55% from 48.4 N to 75.2 N following unilateral fixation (p = 0.0161) and increased by 100% to 96.9 N after bilateral fixation (p = 0.0038). Unilateral SIJ fixation increased flexion of the ilium relative to L5 from 1.2° to 2.0° (p = 0.01) and increased axial rotation of L5 relative to S1 from 0.7° to 1.6° (p = 0.001). Bilateral fixation increased flexion of the ilium relative to L5 to 2.0° from 1.2° prior to fixation (p = 0.001), increased axial rotation of L5 relative to S1 to 1.2° from 0.7° prior to fixation (p = 0.002) and increased flexion of L5 relative to S1 to 2.4° from 1.5° prior to fixation (p = 0.04). ConclusionThe L5/S1 facet joint experiences compensatory increased motion under increased contact force after unilateral and bilateral SIJ fixation, possibly predisposing it to adjacent segment arthritis. Level of EvidenceV, cadaveric study

Evaluation of High-Volume Injections Using a Modified Dorsal Quadratus Lumborum Block Approach in Canine Cadavers.

Simple SummaryThe quadratus lumborum (QL) block is an ultrasound-guided locoregional anesthesia technique. Its objective is to promote both visceral and somatic analgesia for abdominal procedures. Previous spread studies carried out in canine cadavers demonstrated its viability in this species but failed in consistently reach the spinal nerves responsible for the cranial abdominal wall innervation. Therefore, we hypothesize that a modified QL block technique, based on the administration of a higher volume of solution (0.6 mL kg−1) in a dorso-medial position compared to the interfascial injection point between the QL and psoas minor muscles, could enhance its cranial spread, and promote a consistent distribution spread through the ventral branches of the spinal nerves and sympathetic trunk. For this purpose, a solution of dye/contrast was ultrasound-guide injected into six canine cadavers. The results were assessed through computed tomography and dissection, showing that the proposed technique is viable, safe, and stained the median and caudal abdominal nerves and the sympathetic trunk up to T13 consistently. However, our modified technique of QL block did not increase the cranial distribution of dye/contrast to the thoracic spinal nerves, and may not provide adequate somatic analgesia of the cranial abdominal wall.The quadratus lumborum (QL) block targets the fascial plane surrounding the QL muscle providing abdominal somatic and visceral analgesia. The extension of its analgesic effects is a subject of research, as it could not cover areas of the cranial abdomen in dogs. This study assesses in eight thawed canine cadavers, the distribution of high-volume injections (0.6 mL kg−1 of a mixture of methylene blue and iopromide) injected between the psoas minor muscle and the vertebral body of L1. Anatomical features of the area of interest were studied in two cadavers. In another six dogs, QL blocks were performed bilaterally under ultrasound-guidance. The distribution of contrast was evaluated by computed tomography (CT). Hypaxial abdominal muscles were dissected to visualize the dye spread (spinal nerves and sympathetic trunk) in 5 cadavers. The remaining cadaver was refrozen and cross-sectioned. CT studies showed a maximum distribution of contrast from T10 to L7. The methylene blue stained T13 (10%), L1 (100%), L2 (100%), L3 (100%), L4 (60%) and the sympathetic trunk T10 (10%), T11 (20%), T12 (30%), T13 (70%), L1 (80%), L2 (80%), L3 (60%) and L4 (30%). These findings may suggest that despite the high volume of injectate administered, this modified QL block could not produce somatic analgesia of the cranial abdomen, although it could provide visceral analgesia in dogs.

A novel rat model of interbody fusion based on anterior lumbar corpectomy and fusion (ALCF)

BackgroundRats have been widely used as experimental animals when performing fundamental research because they are economical, rapidly reproducing, and heal quickly. While the rat interbody fusion model has been applied in basic studies, existing rat models generally have shortcomings, such as insufficiently simulating clinical surgery. The purpose of this study was to develop a novel rat model of interbody fusion which more closely represents clinical surgery.MethodsThe internal fixation was designed based on physical measurements of the rats’ lumbar spine. Then, ten rats divided into two groups (A and B) underwent anterior lumbar corpectomy and fusion of the L5 vertebrae. Groups A and B were sacrificed four and 8 weeks post-surgery, respectively. Micro-CT and histological examination were used to evaluate the model. Fusion rate, bone volume fraction (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th), and the area ratio of newly formed bone (NB) were calculated for quantitative analysis.ResultsBased on the L5 body dimensions of individual rats, 3D-printed titanium cage of the appropriate size were printed. The operations were successfully completed in all ten rats, and X-ray confirmed that internal fixation was good without migration. Micro-CT suggested that fusion rates in group B (100%) were greater than group A (40%, P < 0.05). The BV/TV (B: 42.20 ± 10.50 vs. A: 29.02 ± 3.25, P < 0.05) and Tb.N (B: 4.66 ± 1.23 vs. A: 1.97 ± 0.40, P < 0.05) were greater in group B than A, and the Tb.Th in group B was lower than group A (B: 0.10 ± 0.04 vs. A: 0.15 ± 0.02, P < 0.05). Histomorphometry results demonstrated that the area ratio of NB in group B were greater than group A (B: 35.72 ± 12.80 vs. A: 12.36 ± 16.93, P < 0.05).ConclusionA rat interbody fusion model based on anterior lumbar corpectomy and fusion has successfully been constructed and verified. It could provide a new choice for fundamental research using animal models of spinal fusion.

Development of a fully automatic deep learning system for L3 selection and body composition assessment on computed tomography

As sarcopenia research has been gaining emphasis, the need for quantification of abdominal muscle on computed tomography (CT) is increasing. Thus, a fully automated system to select L3 slice and segment muscle in an end-to-end manner is demanded. We aimed to develop a deep learning model (DLM) to select the L3 slice with consideration of anatomic variations and to segment cross-sectional areas (CSAs) of abdominal muscle and fat. Our DLM, named L3SEG-net, was composed of a YOLOv3-based algorithm for selecting the L3 slice and a fully convolutional network (FCN)-based algorithm for segmentation. The YOLOv3-based algorithm was developed via supervised learning using a training dataset (n = 922), and the FCN-based algorithm was transferred from prior work. Our L3SEG-net was validated with internal (n = 496) and external validation (n = 586) datasets. Ground truth L3 level CT slice and anatomic variation were identified by a board-certified radiologist. L3 slice selection accuracy was evaluated by the distance difference between ground truths and DLM-derived results. Technical success for L3 slice selection was defined when the distance difference was < 10 mm. Overall segmentation accuracy was evaluated by CSA error and DSC value. The influence of anatomic variations on DLM performance was evaluated. In the internal and external validation datasets, the accuracy of automatic L3 slice selection was high, with mean distance differences of 3.7 ± 8.4 mm and 4.1 ± 8.3 mm, respectively, and with technical success rates of 93.1% and 92.3%, respectively. However, in the subgroup analysis of anatomic variations, the L3 slice selection accuracy decreased, with distance differences of 12.4 ± 15.4 mm and 12.1 ± 14.6 mm, respectively, and with technical success rates of 67.2% and 67.9%, respectively. The overall segmentation accuracy of abdominal muscle areas was excellent regardless of anatomic variation, with CSA errors of 1.38–3.10 cm2. A fully automatic system was developed for the selection of an exact axial CT slice at the L3 vertebral level and the segmentation of abdominal muscle areas.

Case series and a systematic review concerning the level of the aortic bifurcation.

The aim of this study is to present the level of aortic bifurcation in a sample of Greek origin (case series) and to perform an up-to-date systematic review in the existing literature. Seventy-six formalin-fixed adult cadavers were dissected and studied in order to research the level of aortic bifurcation. Additionally, PubMed and Google Scholar databases were searched for eligible articles concerning the level of aortic bifurcation for the period up to February 2020. The mean level of aortic bifurcation according to our case series was the lower third of the L4 vertebral body (21/76, 27.6%). The level of aortic bifurcation ranged between the lower third of the L3 vertebral body and the lower third of the L5 body. No statistically significant correlation was found between the two sexes. The systematic review of the literature revealed 31 articles which were considered eligible and a total number of 3537 specimens were retracted. According to the recorded findings the most common mean level of aortic bifurcation was the body of L4 vertebra (1495/3537 cases, 42.2%), while the range of aortic bifurcation was described to occur from upper third of L3 vertebrae to the upper third of the S1 vertebrae in the 52.8% of the cases (1866/3537). The mean level of AA corresponds to the body of L4 and presents a great range (form L3U to S1U). Knowledge of the mean level of aortic bifurcation and its probable ranges is of great significance for interventional radiologists and especially vascular surgeons that deal with aneurism proximal to the aortic bifurcation.

Biomechanical comparison of 3 types of transdiscal fixation implants for fixing high-grade L5/S1 spine spondylolisthesis

BACKGROUND CONTEXTThere are several options for the stabilization of high-grade lumbosacral spondylolisthesis including transdiscal screws, the Bohlman technique (transdiscal fibular strut) and the modified Bohlman technique (transdiscal titanium mesh cage). The choice of an optimum construct remains controversial; therefore, we endeavoured to study and compare the biomechanical performance of these 3 techniques. PURPOSEThe aim of this study was to compare 3 types of transdiscal fixation biomechanically in an in vitro porcine lumbar-sacral spine model. STUDY DESIGN/SETTINGPorcine cadaveric biomechanical study. METHODS18 complete lumbar-sacral porcine spines were split into 3 repair groups, transdiscal screws (TS), Bohlman technique, and a modified Bohlman technique (MBT). Range of motion (L3 – S1) was measured in an intact and repaired state for flexion, extension, left/right lateral bending, and left/right torsion. To recreate a high-grade lumbosacral spondylolisthesis a bilateral L5/S1 facetectomy, removing the intervertebral disc completely, and the L5 body was displaced 50%–60% over the sacral promontory. Results were analyzed and compared to intact baseline measurements. Standard quasi-static moments (5 Nm) were applied in all modes. RESULTSAll range of motion (ROM) were in reference to intact baseline values. TS had the lowest ROM in all modes (p=.006–.495). Statistical difference was found only in extension for TS vs. BT (p=.011) and TS vs. MBT (p=.014). No bone or implant failures occurred. CONCLUSIONTS provided the lowest ROM in all modes of loading compared to Bohlman technique and MBT. Our study indicates that TS results in the most biomechanically stable construct. CLINICAL SIGNIFICANCEKnowledge of the biomechanical attributes of various constructs could aid physicians in choosing a surgical construct for their patients.

Spinal Intraosseus Schwannoma: A Case Report

Introduction: Schwannomas are the most frequent extramedullary intradural spinal tumors, accounting for approximately 24% of all nerve sheath tumors in adults. In a lower percentage of cases they may be extradural or transdural (1-19%). Intramedullary schwannomas and intraosseous schwannoma are quite rare tumors representing. Case Description: A 74-year-old woman presented intense low back pain for a few months, associated with left cruralgia and dysesthesia spread to both lower limbs. Magnetic resonance and computed tomography examination demonstrated an extramedullary intradural osteolytic lesion located in the posterior part of the vertebral body and pedicles of L1. The patient underwent a first surgery 4 years earlier with complete removal of the tumor but after about two years she had a recurrence. She was then subjected to a new intervention of decompression, removal of the tumor and arthrodesis. The histological findings were compatible with a classical schwannoma characterized by intraosseous growth and multifocal bone infiltration. Conclusion: We reported a rare case of intraosseous schwannoma presenting as a recurrence four years after radical surgical removal of a classic lumbar schwannoma. Only 25 cases of these tumors have been previously reported and none of them as an intraosseous recurrence.

Histiocitose de células Langerhans com acometimento de coluna vertebral em criança portadora de HIV: um relato de caso

Langerhans cell histiocytosis (HCL) is a mainly pediatric disease whose severity is highly variable and clinical presentation depends on the site affected. Excluding craniofacial lesions, the spine is the most frequently involved bone site. A 5-year-old male, admitted to a tertiary hospital with a history of three weeks of low back pain, with irradiation of lower limb pain, which made walking difficult, with partial improvement after the use of anti-inflammatories. He denied traumas, fever or other symptoms during the period. On physical examination, he presented pain on palpation of the lumbar region, absence of skin lesions or other alterations. Previous HIV diag-nosis by vertical transmission, in irregular use of antiretroviral therapy (zidovudine, lamivudine, lopinavir, and ritonavir), with CD4+ cell count of 314/mm3 (12%) and viral load of 28,937 copies (log 4.46). Upon admission, he had normal blood count and high inflammatory activity tests. Computed tomography of the thoracolumbar spine showed destructive lesions of vertebral bodies of T4, T8, and L1. Patient was then submitted to vertebral biopsy, with anatomopatho-logical examination of the tissue, receiving the diagnosis of HCL. In the isolated sample of bone tissue, culture for bacteria and fungi and PCR for tuberculosis were negative. HCL is a disease of difficult suspicion and diagnosis, since its low incidence and nonspecific symptoms, common to many pathologies. For the described patient, HIV infection with high viral load and low concen-tration of CD4+ lymphocytes made the diagnosis even more challenging.

265. Lumbar vertebral body Hounsfield units are associated with cage subsidence after transforaminal lumbar interbody fusion

BACKGROUND CONTEXT Postoperative subsidence of transforaminal lumbar interbody fusion (TLIF) interbody cages can result in loss of lordosis and foraminal height, and in some cases recurrence of nerve root impingement and radicular symptoms. Hounsfield unit (HU) values as measured on computed tomography (CT) can be used in the assessment of bone quality and bone mineral density. PURPOSE Determine the association between HU measurement of the first lumbar vertebral body and cage subsidence after TLIF. We hypothesized that the HU measured in the vertebral body of L1 would be lower in patients with postoperative TLIF cage subsidence. STUDY DESIGN/SETTING Retrospective case-control study. PATIENT SAMPLE NA OUTCOME MEASURES NA METHODS We retrospectively reviewed all patients undergoing instrumented TLIF from two institutions between July 2004 and June 2014. Postoperative imaging studies (radiographs and CT) were evaluated for evidence of implant subsidence. Hounsfield unit values were obtained from the first lumbar vertebral body on postoperative CT scan. Primary outcomes of this study were presence of cage subsidence and measured HU value of first lumbar vertebral body. RESULTS We identified 89 patients with complete imaging who met our inclusion criteria, with a mean clinical follow up of 27 months. Forty-five patients (50.5%) had evidence of interbody cage subsidence. Average cage subsidence was 5.5mm, with a range of 2.2 to 10.8mm. We found implant height was significantly higher in the subsidence group (12.6mm) when compared to the nonsubsidence group (11.2mm). First lumbar vertebral body coronal (170.69±15.61 vs 138.64±14.21; P=0.003), sagittal (175.14±17.26 vs 140.16±13.71; P=0.002), axial (157.57±12.26 vs 134.35±12.30.83; P=0.009), and average HU (167.8±14.04 vs 137.71±12.83; P=0.002) were significantly higher in the non-subsided group vs subsided group (167.8±14.04 vs 137.71±12.83; P=0.002). The subsidence group had a fusion rate of 82% compared to 93% in the nonsubsidence group, although this finding did not reach statistical significance (p=0.08). CONCLUSIONS We found that HU measurements of the first lumbar vertebra are significantly higher in patients without evidence of TLIF cage subsidence when compared to patients with cage subsidence. We identified a trend toward a decreased fusion rate in the subsidence group, yet this finding was not statistically significant. Our findings suggest that HU measurements may function as a surrogate measurement for bone mineral density, and as a predictor for cage subsidence following TLIF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Do we underdiagnose osteoporosis in patients with pyogenic spondylodiscitis?

Pyogenic spondylodiscitis affects a fragile patient population. Surgical treatment in cases of instability entails instrumentation, and loosening of this instrumentation is a frequent occurrence in pyogenic spondylodiscitis. The authors therefore attempted to investigate whether low bone mineral density (BMD)-which is compatible with the diagnosis of osteoporosis-is underdiagnosed in patients with pyogenic spondylodiscitis. How osteoporosis was treated and how it affected implant stability were further analyzed. Charts of patients who underwent operations for pyogenic spondylodiscitis were retrospectively reviewed for clinical data, prior medical history of osteoporosis, and preoperative CT scans of the thoracolumbar spine. In accordance with a previously validated high-fidelity opportunistic CT assessment, average Hounsfield units (HUs) in vertebral bodies of L1 and L4 were measured. Based on the validation study, the authors opted for a conservative cutoff value for low BMD, being compatible with osteoporosis ≤ 110 HUs. Baseline and outcome variables, including implant failure and osteoporosis interventions, were entered into a multivariate logistic model for statistical analysis. Of 200 consecutive patients who underwent fusion surgery for pyogenic spondylodiscitis, 64% (n = 127) were male and 66% (n = 132) were older than 65 years. Seven percent (n = 14) had previously been diagnosed with osteoporosis. The attenuation analysis revealed HU values compatible with osteoporosis in 48% (95/200). The need for subsequent revision surgery due to implant failure showed a trend toward an association with estimated low BMD (OR 2.11, 95% CI 0.95-4.68, p = 0.067). Estimated low BMD was associated with subsequent implant loosening (p < 0.001). Only 5% of the patients with estimated low BMD received a diagnosis and pharmacological treatment of osteoporosis within 1 year after spinal instrumentation. Relying on past medical history of osteoporosis is insufficient in the management of patients with pyogenic spondylodiscitis. This is the first study to identify a substantially missed opportunity to detect osteoporosis and to start pharmacological treatment after surgery for prevention of implant failure. The authors advocate for routine opportunistic CT evaluation for a better estimation of bone quality to initiate diagnosis and treatment for osteoporosis in these patients.

Spinal Metastasis Treated with Percutaneous Radiofrequency Ablation and Vertebroplasty In A Day Care Treatment: A Case Report and Review of The Literature

Case. A 74-year-old woman with renal cell carcinoma had an oligometastatic in the vertebra T7 which was treated surgically and adjuvant radiation therapy. Nine months later, the patient reported severe back pain. CT showed a new metastasis of the vertebral body of L1. This lesion was ablated using percutaneous transpedicular radiofrequency ablation (RFA) in combination with the application of bone cement vertebroplasty. Percutaneous transpedicular RFA was considered beneficial, due to being minimally invasive, possible in a daycare setting and lacking the tissue damage as compared to open surgical treatment. This paper describes the perks of RFA as a treatment in spinal metastasis to create awareness for this valuable alternative palliative treatment in a metastasized setting. Conclusion. Percutaneous radiofrequency ablation in combination with the application of vertebroplasty is a potential minimal invasive option to reduce the tumor load, provide pain relief, and stabilization in daycare.

Paraganglioma of the Spermatic Cord With Spinal Metastasis: A Case Report

A 40-year-old male with presented to the clinic with the chief complaint of right inguinal pain radiating to his right testicle and right thigh with no history of trauma, fever, chills, dysuria, hematuria, or unprotected sexual activity. Physical exam revealed right testicular tenderness with no palpable abnormality of the bilateral testes or spermatic cords. Scrotal ultrasound was performed and was unremarkable for testicular or other intrascrotal pathology. Concurrently, chronic low back pain had prompted a lumbar CT to be performed, which was indeterminate, but subsequent lumbar MRI performed three months later revealed abnormal signals in the vertebral bodies of T12, L3, and L5, concerning for occult metastatic disease or multiple myeloma. PET-CT was performed revealing hypermetabolic lesions throughout the axial skeleton and, most notably, hypermetabolic lesions in the left inguinal and left upper scrotum. At this time, about 4 months after the original visit, physical exam revealed a palpable mobile mass in the left upper scrotum that was distinct from the left testicle, and another mass palpable near the left inguinal ring.