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Chronic low back pain is extremelyfrequent and its management is still con troversial among spine physicians. For decades, intervertebral fusion has been considered as the gold- standard. However, non fusion techniques have been developed in order to avoid fusion's complications. Numerous studies have reported satisfactory results of total disc arthro- plasty in the management of lumbar degenerative disc disease. So far it is still dificult to prove the superiority of disc replacement over fusion due to a lack of high level studies. The aim of this work was to try to answers various questions related to that technique which was described twenty years ago.

An updated classification of the anatomical variations of the internal iliac venous drainage system: Surgical implications for anterior lumbar spinal approaches.

BACKGROUND: Advanced pelvic surgery is associated with potential vascular risks. The aim of this study was to complete the existing classification of the anatomical variations of the internal iliac veins encountered on a series of preoperative angio CT with a view to performing anterior lumbar spine surgery. MATERIALS AND METHODS: In this monocentric retrospective study conducted between 2010 and 2020, all preoperative angio CT performed before an anterior lumbar surgery were systematically analyzed. All the abnormalities of the iliac veins were referenced in an updated classification system. RESULTS: 910 patients (431 men and 479 women) with a mean age of 49 years [16-88] were included. Apart from the most common variant in the population (type I), 64 anatomical variations (7.0%) in the iliac veins were reported and classified according to our new classification. The percentage of coverage of the L4-L5 intervertebral disc is 52%, including 32% by the inferior vena cava before the confluence of the common iliac veins. At the level of the L5-S1 intervertebral disc, the coverage is 30% (same distribution between left and right). CONCLUSIONS: Variations of the iliac veins are frequent, and contrary to what one might think, and even if they can represent an anatomical trap during surgery, certain variations do not limit anterior lumbar spine surgery and are not more associated with vascular complications. Nevertheless, these anatomical variations must be known before any advanced pelvic surgery. Depending on their distribution, level L5-S1 is more suitable for ALIF, level L4-L5 for OLIF approaches.

The proximal femur fracture epidemic continued during the COVID-19 pandemic: Results of an observational study.

INTRODUCTION: The aim of this study was to compare the volume and characteristics of emergency trauma surgery procedures done at our hospital between March 20 and April 20, 2020 (the first month of the national lockdown in France) and to compare these data to the same period in 2019. We hypothesized that a portion of fractures are unavoidable, thus specific preventative measures will be needed to reduce their incidence. METHODS: This was a continuous, observational and single center study. All patients who required urgent surgery for a fracture between March 20 and April 20, 2020, were included. Data for the same period in 2019 was retrieved. All the procedures were done at our hospital, which is a regional level II trauma center. RESULTS: During the first month of the lockdown, 70 patients underwent emergency surgery because of a fracture, versus 109 patients in the same period in 2019, thus an overall 36% drop. The mean age of the patients was higher in 2020 (68.4 years SD=22) than in 2019 (60.3 years SD=24, p=0.0210). There were fewer recreational and motor vehicle accidents in 2020 (34 vs. 10) and fewer work-related accidents (7 vs. 2) although the number of accidents at home were similar (65 vs. 55). CONCLUSION: During a public health emergency, it is vital to continue doing trauma surgery procedures, even though it requires a specific care pathway. The lockdown and associated behavioral changes have altered the spectrum of trauma surgery. A major decrease in motor vehicle, recreation and work-related accidents is the avoidable portion of this surgical activity, justifying specific preventative measures during a public health crisis. Conversely, the incidence of geriatric fractures - particularly of the proximal femur - did not change much overall, thus there is need for additional preventative measures in these patients. LEVEL OF EVIDENCE: V, observational study.

Systems for long-segment percutaneous spinal fixation: technical feasibility for various indications.

SUMMARY OF BACKGROUND DATA: New methods of spinal percutaneous fixation are developing very rapidly. However, few studies to date have focused on long-segment methods of instrumentation. OBJECTIVE: To report the technical feasibility of long-segment percutaneous stabilization for various indications. METHODS: The study included 24 patients with a mean age of 58 years (range 38-79). The etiologies included trauma, infection, tumors, or pathology secondary to degenerative lumbar scoliosis. The damaged vertebrae ranged from T5 to L4. All of the patients underwent posterior percutaneous long-segment fixation. When necessary, the anterior spinal column was stabilized by balloon kyphoplasty or via anterior approach. The results obtained were analyzed on the basis of clinical and radiological criteria. RESULTS: The constructs involved four levels on average per patient, located between T3 and S1. No extra-pedicular misplacements were observed. Two technical difficulties were noticed without clinical consequences. A significant improvement in the pain levels was obtained in all the patients in this series. CONCLUSIONS: Long-segment percutaneous fixation was found to be technically feasible and to considerably improve the patients' spinal deformations. When associated with balloon kyphoplasty, this intervention seems to provide less loss of correction than previous methods, and posterior fusion was therefore not required. As with all new methods, there is a learning curve, and the indications have to be strictly observed. Further studies need to be performed, however, with a longer follow-up to confirm the absence of long-term complications.

Treatment of osteoporotic vertebral fractures.

Osteoporosis is a public health problem that is contributing to an increasing number of osteoporotic vertebral fractures. The aim of this lecture is to summarize the current state of knowledge about osteoporotic fractures by answering five questions. 1/How does the spine typically age and how is osteoporosis diagnosed? Various normal aging processes will gradually modify the vertebral column (static, dynamic, bone quality). Osteoporosis is diagnosed through a DEXA scan. 2/How is an osteoporotic fracture evaluated clinically and radiologically? Magnetic resonance imaging is the preferred modality for making the diagnosis and selecting the most appropriate treatment. 3/What are the treatment options for an osteoporotic fracture? The options are conservative treatment, conventional surgery, and minimally invasive techniques (cementoplasty, percutaneous instrumentation). 4/Which fractures should be treated, and which technique should be used? The choice is clear when neurological deficits are present, although the indications are less firm when there is no deficit. The treatment can be conservative (back brace) if the fracture is non-displaced and minimally painful, vertebroplasty if the fracture is painful and shows hyperintensity on T2-STIR sequences, vertebral expansion if the radiological deformity worsens along with symptoms. 5/What are the technical challenges and complications related to the presence of osteoporosis when treating vertebral fractures surgically? The reduced bone stock increases the risk of poor implant hold and postoperative mechanical complications (adjacent fracture, junctional kyphosis). Technical solutions have been developed (augmented screw fixation, transitional zone) to limit their impact. It is essential to know and master these techniques, and their indications. Treatment of the osteoporosis itself is crucial. Level of evidence V; Expert opinion.

Minimally invasive triangular lumboiliac and iliosacral fixation of posterior pelvic ring injuries with vertical instability: Technical note.

To date, no strong consensus exists on the best way to treat posterior pelvic ring injuries when there is no neurological deficit. Various fixation methods have been described; more recently, constructs that combine lumboiliac and iliosacral fixation have been introduced. This type of fixation is mainly indicated in cases of spinopelvic dissociation with large displacement of fracture fragments in the sagittal plane. However, these techniques are associated with postoperative complications, particularly infections and severe skin complications. This led us to propose a minimally invasive lumboiliac and iliosacral fixation technique for posterior pelvic ring injuries. The procedure is done with the patient prone. It consists of pedicle screw insertion into L4 or L5 and screw fixation of the ilium with fluoroscopy guidance; intraoperative distraction can be done depending on the amount of displacement. An iliosacral screw is then inserted percutaneously to allow reduction in the transverse plane and yield a triangular construct. In the five patients that we have operated using this technique, the mean preoperative vertical displacement was 11.9±6.9mm (SD) (min 1.3, max 19.7) versus 3.7±3.2mm (min 0.3, max 6.7) postoperatively and the mean preoperative frontal displacement was 7.5±3.7mm (min 4.2, max 12.4) versus 2.5±2.0mm (min 0.3, max 4.3) postoperatively. Minimally invasive iliosacral and lumboiliac fixation is an option for treating posterior pelvic ring fractures free of neurological deficit and especially spinopelvic dissociation.

Sagittal reduction of spinal deformity: Superior versus lateral screw-rod connection.

INTRODUCTION: Spinal malalignment can greatly impact a patient's quality of life. Various sagittal parameters are used as realignment goals; however, about 50% of patients end up being under-corrected postoperatively. To improve the correction, prebent rods are available with a radius of curvature corresponding to the patient's "ideal" sagittal alignment. But no studies have been done on how the radius of curvature changes according to the type of connection between the pedicle screws and rods. The goal of this experimental study was to quantify how much prebent rods flatten based on the method used to connect the screw and rod: top-loading screw vs. dome screw with lateral connector. METHODS: The experiment was done on a material testing system in axial compression on three constructs consisting of two rods secured with top-loading screws and three other constructs consisting of two rods secured with dome screws and lateral connector. The maximum angle of the construct was measured during loading and after removing the load. The primary outcome measure was the mean angle in each construct at each step. RESULTS: The mean angle of the constructs with top-loading screws when subjected to 500 N load was significantly less than in the constructs with dome screws and lateral connector: 18.6° vs. 24.5° respectively (p<0.0003). The mean angle of the constructs with top-loading screws after removing the load was significantly less than in the constructs with dome screws and lateral connector: 25.7° vs. 32.3° respectively, (p<0.0005). CONCLUSION: In vitro, top-loading screws produced significantly greater flattening than dome screws with lateral connector. These findings must be confirmed in vivo. Understanding the behavior of rods as a function of the type of screw connection can be an important factor to minimize the risk of under-correction in the sagittal plane. LEVEL OF EVIDENCE: III.

Accessory iliac vein: surgical implications.

BACKGROUND: One of the main difficulties in using an anterior retroperitoneal approach in prosthetic lumbar disk replacement surgery is the exposure of the anterior aspect of the spine because of the risk of hemorrhage because of vascular injury when the venous structures are mobilized. PURPOSE: The goal of our study was to use computed tomography (CT) to research for anatomic variations of the ileocaval drainage network, which were likely to complicate this type of procedure. DESIGN: Prospective study. PATIENT SAMPLE: Ninety patients (48 males, 42 females) explored between July 2003 and February 2007. OUTCOME MEASURES: Not applicable. METHODS: All the patients had a CT scan before disk replacement surgery to treat degenerative lumbar disk disease by a microinvasive, anterior retroperitoneal approach. RESULTS: Eighteen of 90 patients presented with variations in their iliocaval drainage network: 3 cases of double inferior vena cava, 1 case of duplication of the inferior vena cava, 5 cases of ectopic internal iliac veins, 9 cases of accessory iliac veins. CONCLUSIONS: Anatomical variations in the iliocaval venous drainage system are fairly frequent but easy to analyze by CT. Even if they have no functional impact, they must be analyzed and described because they can be of great interest in the preoperative workup for retroperitoneal lumbar surgery.

"Patient-specific" rods in the management of adult spinal deformity. One-year radiographic results of a prospective study about 86 patients.

INTRODUCTION: Based on global knowledge regarding sagittal alignment, preoperative planning is a crucial point in the management of adult spinal deformity (ASD). Patient-specific rods (PSR) have been recently developed in order to change preoperative planning into a postoperative reality. The aim of this study was therefore to analyze the 1-year radiographic results of prospective ASD cohorts managed using PSR. METHODS: In this prospective study, all patients managed for an ASD using PSR since 2014 and with a minimal follow-up of 1-year were included. Radiographic parameters were evaluated pre and postoperatively and patients were stratified according to their final sagittal alignment status (A: aligned vs. MA: malaligned) according to the age-related Schwab classification. Statistical analyses were performed using the Student's-t-test in order to compare groups. RESULTS: Eighty-six patients were included in the study, with a mean age of 57.2 years. At one-year follow-up, mean sagittal vertical axis and pelvic incidence-lumbar lordosis mismatch were significantly improved. Twenty-two patients were aligned on both sagittal and coronal planes, 52 patients were still considered as malaligned in the sagittal plane, 3 were still malaligned in the coronal plane and 9 patients were malaligned in both planes (vs. 42 patients preoperatively). At final follow-up, the rate of mechanical complications was 18%. CONCLUSION: Based on our results, patient-specific rods can represent a useful supplementary tool in the management of ASD and transform preoperative planning into a postoperative reality. Corrections rates are comparable to other series in the literature with conventional rods, and fewer complications have been reported. However, further studies will be required in order to confirm these results.

Sacral hiatus corticosteroid injection in the management of radicular pain in adults.

Radicular pain is a common reason for patients to consult at back pain clinics. While epidural steroid injections are widely done, some aspects are still controversial. The epidural space can be accessed via a transforaminal approach, an interlaminar route or by passing through the sacral hiatus. The aim of this article is to describe the epidural injection technique through the sacral hiatus that our team uses and to report our experience with it. Beyond the treatment effect, sacral hiatus corticosteroid injection can be useful as a diagnostic test or as an interim solution. Image-guided injection is recommended to ensure optimal positioning of the needle below S3. Sacral hiatus corticosteroid injection is a relevant alternative for treating lumbar radiculopathy in adults.

French Spine Surgery Society guidelines for management of spinal surgeries during COVID-19 pandemic.

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019 in China, various measures have been adopted in order to attenuate the impact of the virus on the population. With regard to spine surgery, French physicians are devoted to take place in the national plan against COVID-19, the French Spine Surgery Society therefore decided to elaborate specific guidelines for management of spinal disorders during COVID-19 pandemic in order to prioritize management of patients. A three levels stratification was elaborated with Level I: Urgent surgical indications, Level II: Surgical indications associated to a potential loss of chance for the patient and Level III: Non-urgent surgical indications. We also report French experience in a COVID-19 cluster region illustrated by two clinical cases. We hope that the guidelines formulated by the French Spine Surgery Society and the experience of spine surgeons from a cluster region will be helpful in order optimizing the management of patients with urgent spinal conditions during the pandemic.

Computation of Intersegmental Moments during Standing Posture: Can We Neglect the Horizontal Ground Reaction Force? Results from an Experimental Study.

BACKGROUND: The development of postural analysis thanks to force and pressure platforms, in order to determine the center of pressure, can be valuable in the setting of spinal malalignment. The purpose of this study was to compare "pressure" and "force" platforms for the evaluation of the center of pressure. In other words, can we neglect the horizontal ground reaction force in the evaluation of intersegmental moments during standing posture? Methods. Postural data from two healthy adult volunteers were analyzed. Analysis of the posture was done according to a protocol providing sagittal intersegmental moments. A set of 36 markers was used to divide the body in 10 segments. Postacquisition calculations were done in order to obtain the sagittal net intersegmental moments. To evaluate the differences in intersegmental moments between force and pressure platforms, the postacquisition calculations were done with a simulated pressure platform. Mean intersegmental moments between each body segment for each volunteer were compared. FINDINGS: There were significant differences between the 2 platforms in intersegmental moments for the lumbo-sacral junction, hips, knees, and ankles (p < 0.005). All differences were inferior to intrasubject variability measured with the force platform (p < 0.001). Results from intra- and interobserver comparisons showed that differences measured with the pressure platform were all inferior to the standard error obtained with the force platform for every intersegmental moment (p < 0.001). INTERPRETATION: The use of a simulated pressure platform to determine intersegmental moments has the same clinical efficiency as force platforms. Moreover, the possibility to set the platform into the radiograph room will allow in a second time a correlation between radiographic parameters and biomechanical constraints applied to the spine.

Surgeon's and patient's radiation exposure during percutaneous thoraco-lumbar pedicle screw fixation: A prospective multicenter study of 100 cases.

HYPOTHESIS: Percutaneous pedicle screw fixations (PPSF) are increasingly used in spine surgery, minimizing morbidity through less muscle breakdown but at the cost of intraoperative fluoroscopic guidance that generates high radiation exposure. Few studies have been conducted to measure them accurately. MATERIAL AND METHODS: The objective of our study is to quantify, during a PPSF carried out in different experimented centers respecting current radiation protection recommendations, this irradiation at the level of the surgeon and the patient. We have prospectively included 100 FPVP procedures for which we have collected radiation doses from the main operator. For each procedure, the doses of whole-body radiation, lens and extremities were measured. RESULTS: Our results show a mean whole body, extremity and lens exposure dose per procedure reaching 1.7±2.8µSv, 204.7±260.9µSv and 30.5±25.9µSv, respectively. According to these values, the exposure of the surgeon's extremities and lens will exceed the annual limit allowed by the International Commission on Radiological Protection (ICRP) after 2440 and 4840 procedures respectively. CONCLUSION: Recent European guidelines will reduce the maximum annual exposure dose from 150 to 20mSv. The number of surgical procedures to not reach the eye threshold, according to our results, should not exceed 645 procedures per year. Pending the democratization of neuronavigation systems, the use of conventional fluoroscopy exposes the eyes in the first place. Therefore they must be protected by leaded glasses. LEVEL OF PROOF: IV, case series.

Lumbar total disc replacement. Surgical technique.

BACKGROUND: Symptomatic lumbar degenerative disc disease is a challenging entity to treat. The results of arthrodesis may be compromised in the short term by pseudarthrosis and in the long term by pain at the iliac-crest donor site and by junctional degeneration. Total disc replacement has the potential to provide long-lasting relief to these patients. The purpose of this study was to present the clinical and radiographic results assessed seven to eleven years following a Prodisc total lumbar disc replacement. METHODS: Sixty-four patients had single or multiple-level implantation of a total lumbar disc replacement between 1990 and 1993. The mean duration of follow-up was 8.7 years. Clinical results were evaluated by assessing preoperative and postoperative lumbar pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Preoperative and post-operative radiographs were evaluated by assessing preoperative and postoperative lumbar pain, radiculopathy, disability, and modified Stauffer-Coventry scores. Preoperative and post-operative radiographs were evaluated as well. Subgroup analysis was performed to determine if gender, an age of less than forty-five years, previous surgery, or multilevel surgery had an effect on outcome. RESULTS: At an average of 8.7 years post-operatively, there were significant improvements in the backpain, radiculopathy, disability, and modified Stauffer-Coventry scores. Thirty-three of the fifty-five patients with sufficient follow-up had an excellent result, eight had a good result, and fourteen had a poor result. Neither gender nor multilevel surgery affected outcome. An age of less than forty-five years and prior lumbar surgery had small but significant negative effects on outcome. Radiographs did not demonstrate loosening, migration, or mechanical failure in any patient. Five patients had approach-related complications. CONCLUSIONS: The Prodisc lumbar total disc replacement appears to be effective and safe for the treatment of symptomatic degenerative disc disease. Gender and multilevel surgery did not affect the outcomes, whereas prior lumbar surgery or an age of less than forty-five years was associated with slightly worse outcomes. Longer follow-up of this cohort of patients and randomized trials comparing disc replacement with arthrodesis are needed.

Range of motion and adjacent level degeneration after lumbar total disc replacement.

BACKGROUND CONTEXT: There are no published studies on the relationship between total disc replacement (TDR) motion and the development of adjacent level degeneration (ALD). Because prevention of ALD is the underlying justification for TDR, studies investigating the validity of this concept are essential. PURPOSE: To examine the relationship between range of motion (ROM) and ALD 8.7 years after lumbar TDR. STUDY DESIGN/SETTING: Retrospective radiographic and chart review. PATIENT SAMPLE: Forty-two patients 8.7 years after lumbar TDR. OUTCOME MEASURES: Radiographic flexion-extension and ALD. Modified Stauffer-Coventry score. Oswestry Disability Questionnaire. Subjective patient ratings of back pain, leg pain, and disability. METHODS: We reviewed the flexion-extension radiographs of 42 patients 8.7 years after TDR. Cephalad adjacent levels were evaluated for degeneration: loss of disc space height, anterior osteophyte formation, or dynamic flexion-extension instability. Graphical analysis of motion and the prevalence of ALD was performed. A statistical relationship between ALD and clinical outcome was sought. RESULTS: Ten of 42 patients evaluated (24%) had radiographic ALD. The mean motion was 3.8 degrees +/-2.0 degrees. The patients with ALD had mean motion of 1.6 degrees +/-1.3 degrees whereas the patients without ALD had motion of 4.7 degrees +/-4.5 degrees (p=.035). A clear relationship between motion and the presence of ALD at 8.7-year follow-up was observed. Patients with motion 5 degrees or greater (n=13) had a 0% prevalence of ALD. Patients with motion less than 5 degrees (n=29) had a 34% prevalence of ALD (p=.021, odds ratio 13.5). ALD had no statistically significant effect on clinical outcome although the sample size was small. CONCLUSIONS: At 8.7-year follow-up, the prevalence of ALD after TDR is higher in patients with motion less than 5 degrees. The presence of ALD had no significant effect on clinical outcome, but the sample size was small. These data suggest that patients with significant ROM after lumbar TDR may have reduced risk for radiographic ALD.