Crystallinity dependency of the time-dependent mechanical response of polyethylene: application in total disc replacement.

Degeneration of the intervertebral disc (IVD) is a leading source of chronic low back pain or neck pain, and represents the main cause of long-term disability worldwide. In the aim to relieve pain, total disc replacement (TDR) is a valuable surgical treatment option, but the expected benefit strongly depends on the prosthesis itself. The present contribution is focused on the synthetic mimic of the native IVD in the aim to optimally restore its functional anatomy and biomechanics, and especially its time-dependency. Semi-crystalline polyethylene (PE) materials covering a wide spectrum of the crystallinity are used to propose new designs of TDR. The influence of the crystallinity on various features of the time-dependent mechanical response of the PE materials is reported over a large strain range by means of dynamic mechanical thermo-analysis and video-controlled tensile mechanical tests. The connection of the stiffness and the yield strength with the microstructure is reported in the aim to propose a model predicting the crystallinity dependency of the response variation with the frequency. New designs of TDR are proposed and implemented into an accurate computational model of a cervical spine segment in order to simulate the biomechanical response under physiological conditions. Predicted in-silico motions are found in excellent agreement with experimental data extracted from published in-vitro studies under compression and different neck movements, namely, rotation, flexion/extension and lateral bending. The simulation results are also criticized by analyzing the local stresses and the predicted biomechanical responses provided by the different prosthetic solutions in terms of time-dependency manifested by the hysteretic behavior under a cyclic movement and the frequency effect.

Evaluation of non-supervised MALDI mass spectrometry imaging combined with microproteomics for glioma grade III classification.

An integrated diagnosis using molecular features is recommended in the 2016 World Health Organization (WHO) classification. Our aim was to explore non-targeted molecular classification using MALDI mass spectrometry imaging (MALDI MSI) associated to microproteomics in order to classify anaplastic glioma by integration of clinical data. We used fresh-frozen tissue sections to perform MALDI MSI of proteins based on their digestion peptides after in-situ trypsin digestion of the tissue sections and matrix deposition by micro-spraying. The generated 70µm spatial resolution image datasets were further processed by individual or global segmentation in order to cluster the tissues according to their molecular protein signature. The clustering gives 3 main distinct groups. Within the tissues the ROIs (regions of interest) defined by these groups were used for microproteomics by micro-extraction of the tryptic peptides after on-tissue enzymatic digestion. More than 2500 proteins including 22 alternative proteins (AltProt) are identified by the Shotgun microproteomics. Statistical analysis on the basis of the label free quantification of the proteins shows a similar classification to the MALDI MSI segmentation into 3 groups. Functional analysis performed on each group reveals sub-networks related to neoplasia for group 1, glioma with inflammation for group 2 and neurogenesis for group 3. This demonstrates the interest on these new non-targeted large molecular data combining both MALDI MSI and microproteomics data, for tumor classification. This analysis provides new insights into grade III glioma organization. This specific information could allow a more accurate classification of the biopsies according to the prognosis and the identification of potential new targeted therapeutic options. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.

Minimally invasive costotransversectomy for the resection of large thoracic dumbbell tumors.

BACKGROUND: Due to their important size and complex localization, the management of thoracic dumbbell tumors is challenging, frequently requiring the need for an anterior approach. Our study aims to first report the feasibility and safety of a single-stage posterior minimally invasive procedure in achieving complete resection of voluminous thoracic dumbbell tumors. METHODS: We retrospectively reviewed the medical records of five consecutive patients, who underwent the minimally invasive resection of a type III thoracic dumbbell tumor in our institution between March 2007 and March 2012. There were two men and three women, with a mean age at diagnosis of 57 years (range 41-68 years). After the placement of a non-expandable tubular retractor under fluoroscopic control, a costotransversectomy was achieved. By moving the retractor in all directions, the tumor was largely exposed and resected with the cavitron ultrasonic surgical aspirator. Clinical and radiological monitoring was performed before discharge, at 6 months, 1 year and 2 years. RESULTS: No major intraoperative complication was reported. Gross total resection was achieved in four patients. The mean operative time was 219 mins (range 75-540 mins) and the mean estimated blood loss was 230 ml (range 50-500 ml). No postoperative complication was reported. The mean length of hospital stay was 3.6 days (range 2-6 days) and all patients were discharged home. Histological analysis confirmed the diagnosis of grade 1 schwannoma in four patients and revealed a hemangiopericytoma in one patient. No tumor recurrence was noted with a mean follow up period of 46 months (range 32-54 months). CONCLUSION: Thoracic dumbbell tumors can be safely and completely resected using a single-stage minimally invasive procedure. The costotransversectomy can be performed through a non-expandable retractor allowing sufficient access to all parts of the tumor.

Evaluation of the relevance of surgery in a retrospective case series of patients who underwent the surgical treatment of a symptomatic spine metastasis from lung cancer.

BACKGROUND: The management of spine metastases is an increasing concern for spine surgeons. When considering surgery, it is crucial to ensure that its iatrogenic effects will not exceed its potential benefits, particularly in frail patients with short life expectancy. Among all prognostic factors, the primary site of cancer is the most important, lung cancer being the poorest. Although surgery has shown its effectiveness in the management of spine metastases, there is a lack of studies focusing on lung cancer alone. PURPOSE: To assess the effectiveness and safety of surgery in the management of symptomatic spine metastases from lung cancer. METHODS: We retrospectively reviewed all patients (n = 53) who underwent surgery for spine metastasis from lung cancer at the Lille University Hospital between January 2005 and December 2011. Patients for whom surgery was effective to restore or preserve ambulation, to relieve pain, and to ensure stability without severe complication were considered "surgical success". RESULTS: No patient was lost to follow-up and vital status data were available for all patients. The median survival was 2.1 months and was not influenced by the surgical success (p = 0.1766). We reported seven major complications in seven patients, including three epidural haematoma, two massive pulmonary embolisms and two deaths from cardiopulmonary failure. The surgical success rate was 49 % and on univariate analysis, the factors that have influenced the postoperative outcome were the KPS (p < 0.001), the Frankel grade (p = 0.0217) and the delay between the cancer diagnosis and the occurrence of spine metastases (p = 0.0216). CONCLUSION: A strict patient selection is required to limit the iatrogenic effect of surgery, which may alter the quality of life of these frail patients with limited life expectancy.

Complications related to the use of an intraventricular access device for the treatment of leptomeningeal metastases from solid tumor: a single centre experience in 112 patients.

Ventricular access devices (VAD) offer several advantages compared to intralumbar injections for the administration of intra-CSF agents in the treatment of leptomeningeal metastases (LM). However, there are few prospective studies reporting on complications with the use of VADs. All complications were prospectively collected that pertained to the implantation and use of a VAD in consecutive patients with solid tumor-related LM from June 2006 to December 2013. Clinical follow-up was every 2 weeks during the initial 2 months of treatment and then once monthly. Complete neuraxis MRI was performed at baseline and then every 2-3 months. A total of 112 patients (88 women) with a mean age of 51.1 years (range 26-73) were included. Primary cancers included breast (79 patients), lung (12) and melanoma (6). All patients were treated with intra-CSF liposomal cytarabine. 72 % of the patients received concomitant systemic and intra-CSF chemotherapy. The placement of the VAD was performed under local anesthesia in all cases. The mean operative time was 15 min and no perioperative complications were reported. The mean number of intraventricular injections per patient was 9.34 (range 1-47). A total of 11 complications in 11 patients were seen including 7 infections, 1 intracranial hemorrhage, 2 instances of symptomatic leukoencephalopathy and 1 catheter malpositioning. 8 complications required an operation and 1 complication was fatal. The use of a VAD is safe and may improve patients' comfort and compliance with LM-directed therapy.

Surgical-site infection in spinal injury: incidence and risk factors in a prospective cohort of 518 patients.

PURPOSE: To investigate the incidence of surgical-site infection (SSI) and determinate the risk factors of SSI in the context of spinal injury. METHODS: From February 1, 2011 to July 31, 2011, for a multicentre cohort of patients with acute spinal injury, we prospectively censored those with SSI for at least 12 months. We recorded epidemiologic characteristics and details of surgical procedure and postoperative care for each patient. We calculated the incidence of SSI at 1, 3 and 12 months after surgery. Univariate and multivariate analysis were used to establish the association of risk factors and SSI. We studied clinical outcomes by a visual analog scale for pain and physical and mental component summaries (PCS and MCS) of the Medical Outcomes Survey 36-Item Short Form (SF-36). RESULTS: At 1 year, among 518 patients, we recorded 25 SSI events, with median occurrence at 16 days (25-75 % quartile: 13-44 days). Incidence of SSI was 3.2 % (95 % confidence interval [1.9-5.3 %]) at 1 month, 3.7 % (95 % [2.2-5.8 %]) at 3 months and 4.6 % (95 % CI [3-6.9 %]) at 12 months. On multivariate analysis, age, presence of diabetes and surgical duration were predictors of SSI (p = 0.009, p = 0.047, and p = 0.015 respectively). At 12 months, infected and non-infected patients did not differ in pain (p = 0.58) or SF-36 PCS (p = 0.8) or MCS (p = 0.68). CONCLUSIONS: In this large prospective multicentre study in the context of spinal injury, we obtained an equivalent incidence rate and risk factors of SSI as found in the literature for elective spinal surgery.

Causes of mortality in neurofibromatosis type 2.

OBJECT: The causes of mortality in neurofibromatosis type 2 (NF2) patients are poorly studied in the literature. Our study aimed to fit this gap by analyzing the main causes of death in this population. METHODS: This study is the retrospective review of prospectively collected data of 80 patients with NF2 disease followed in Lille University Hospital between 1987 and 2011. Demographical data, diagnosis criteria, and cause of death were recorded. RESULTS: There were 45 men and 35 women, with a mean age at diagnosis of 27.2 years (range: 6-73 years; SD: ± 15.4). Sixty-eight patients met Manchester criteria and the others had an identified mutation in the NF2 gene which confirmed the diagnosis. Of all patients, we noted 7 deaths. The mean age at diagnosis of dead patients was 26 years. The mean age of death was 38.9 years. The causes of death were suicide in 1 patient, hematoma after surgical removal of grade IV vestibular schwannoma in 1 patient, aspiration pneumonia after swallowing disturbances in 3 patients, intracranial hypertension related to growth of multiple meningiomas in 1 patient, and brachial plexus sarcoma grade 3 in the last patient. CONCLUSION: NF2 is a serious disease that can quickly be life-threatening. The presence of lower cranial nerves schwannomas is a poor prognostic factor, and radiosurgery should be considered for their treatment, as surgical removal often worsens the swallowing disturbances. A psychological support should also be provided.

CSF CA 15-3 in breast cancer-related leptomeningeal metastases.

UNLABELLED: The sensitivity of CSF cytology, the standard method for diagnosis of leptomeningeal metastases (LM), is low. Serum cancer antigen 15-3 (CA 15-3) is frequently used for the monitoring of patients with breast cancer (BC) and is a laboratory test available in most centers. The aim of the current study was to determine the feasibility of measuring CSF CA 15-3 and CA 15-3 CSF/serum ratio in patients with BC-related LM. Serum and CSF CA 15-3 values were evaluated in 20 BC patients with LM (Group 1), 20 patients with LM from other primary cancers (Group 2), 20 BC patients with parenchymal brain metastases only (Group 3) and 20 controls (Group 4). CSF and serum were collected on the same day. Serum and CSF CA 15-3 were assessed by an automatized immuno-enzymatic technology (TRACE(®) technology, KRYPTOR Automate, Brahms Society, France). In univariate analysis, BC patients with LM (Group 1) compared to other groups, a significantly elevated serum CA 15-3 (median 51 U/ml, range 12-2819) and CSF CA 15-3 (median 8.7 U/ml, range 0.1-251) was observed. Additionally, the CSF/serum ratio of CA 15-3 was significantly higher in this group of patients (median 0.18, range 0.002-4.40). Multivariate analysis identified a cut-off for CSF CA15-3 with 80 % sensitivity and 70 % specificity. CONCLUSIONS: The current study confirms the feasibility of determining CSF CA 15-3 using a widely available technology. Evaluation of the CSF CA 15-3 may be useful in the diagnosis and management of BC-related LM but further studies are needed.

Glioblastoma occurring after the surgical resection of a craniopharyngioma.

The authors report the case of a man who underwent cranial surgery for the removal of a craniopharyngioma using a right pterional approach. Three months later, he developed a right-sided temporal glioblastoma. The presentation is suggestive of a causal relationship between surgery and the development of a malignant glial tumor.

[Leptomeningeal metastases from solid tumors]. / Métastases leptoméningées des tumeurs solides.

The incidence of leptomeningeal metastases is increasing, due to the improvement of the management and the overall survival of cancer patients. Although the diagnosis may be sometimes difficult to assess, an early treatment before the setting of neurological deficits is required in order to improve the quality of life of the patients. The median survival of untreated patients is 4 to 6 weeks. Specific treatment may prolong survival by several months. The treatment requires a combination of chemotherapy and targeted therapies administrated systemically or via intra-cerebrospinal fluid route, surgery and radiotherapy. Patient management is specific but requires a multidisciplinary approach, which may vary according to the characteristics of meningeal disease, the characteristics of primary tumors, the general condition of patients and previous lines of treatments.

Comprehensive analysis of damage evolution in human annulus fibrosus: Numerical exploration of mechanical sensitivity to biological age-dependent alteration.

BACKGROUND AND OBJECTIVE: The annulus fibrosus is an essential part of the intervertebral disc, critical for its structural integrity. Mechanical deterioration in this component can lead to complete disc failure, particularly through tears development, with radial tears being the most common. These tears are often the result of both mechanical and biological factors. This study aims to numerically investigate the mechanisms of radial failure in the annulus tissue, taking into account the mechanical and age-dependent biological damage origins. A newly developed microstructure-based model was upgraded to predict damage evolution in the different annulus regions. METHODS: The study employs a computational model to predict mechanical failures in various annulus regions, using experimental data for comparison. The model incorporates age-dependent microstructural changes to evaluate the effects of biological aging on the mechanical behavior. It specifically includes a detailed analysis of the temporal changes in circumferential rigidity and failure strain of the annulus. RESULTS: The model demonstrated a strong ability to replicate the experimental responses of the different annulus regions to failure. It revealed that age-related microstructural changes significantly impact the rigidity and failure response of the annulus, particularly in the posterior regions and as well the anterior inner side. These changes increase susceptibility to rupture with aging. A correlation was also observed between the composition of collagen fibers, water content, and the annulus transversal response in both radial and axial directions. CONCLUSION: The findings challenge previous assumptions, showing that age-dependent microstructural changes have a notable effect on the annulus mechanical properties. The computational model closely aligns with experimental observations, underscoring the determinant role of oriented collagen fibers in radial failure. This study enhances the understanding of annulus failure and provides a foundation for further research on the impact of aging on disc mechanical integrity and failure.

Overloading effect on the osmo-viscoelastic and recovery behavior of the intervertebral disc.

In vitro studies investigating the effect of high physiological compressive loads on the intervertebral disc mechanics as well as on its recovery are rare. Moreover, the osmolarity effect on the disc viscoelastic behavior following an overloading is far from being studied. This study aims to determine whether a compressive loading-unloading cycle exceeding physiological limits could be detrimental to the cervical disc, and to examine the chemo-mechanical dependence of this overloading effect. Cervical functional spine units were subjected to a compressive loading-unloading cycle at a high physiological level (displacement of 2.5 mm). The overloading effect on the disc viscoelastic behavior was evaluated through two relaxation tests conducted before and after cyclic loading. Afterward, the disc was unloaded in a saline bath during a rest period, and its recovery response was assessed by a third relaxation test. The chemo-mechanical coupling in the disc response was further examined by repeating this protocol with three different saline concentrations in the external fluid bath. It was found that overloading significantly alters the disc viscoelastic response, with changes statistically dependent on osmolarity conditions. The applied hyper-physiological compressive cycle does not cause damage since the disc recovers its original viscoelastic behavior following a rest period. Osmotic loading only influences the loading-unloading response; specifically, increasing fluid osmolarity leads to a decrease in disc relaxation after the applied cycle. However, the disc recovery is not impacted by the osmolarity of the external fluid.

Salvage intracerebrospinal fluid thiotepa in breast cancer-related leptomeningeal metastases: a retrospective case series.

There is currently a paucity of data on salvage intracerebrospinal fluid (intra-CSF) chemotherapy in leptomeningeal metastases (LM). This report is a single-institution experience with salvage treatment in patients with breast cancer (BC) and LM. This retrospective cohort describes 24 consecutive patients with BC selected for a second-line of treatment for LM. The first line of LM treatment consisted of intra-CSF liposomal cytarabine in all patients combined with systemic therapy in 18 cases and radiotherapy in four cases. Second-line (salvage) treatment utilized intra-CSF thiotepa in all and systemic chemotherapy in nine patients. No patient received CNS-directed radiotherapy. The median Eastern Cooperative Oncology Group performance status at initiation of intra-CSF thiotepa treatment was 3 (range 1-4). The median progression-free survival and median survival following intra-CSF thiotepa was 3.1 months (range 3 days-2 years) and 4.0 months (range 6 days-2.5 years), respectively. The median overall survival from LM diagnosis was 9.5 months (range 1.3 months-2.7 years). No grade 3 or higher toxicity was observed. Recognizing the limits of a retrospective study, intra-CSF thiotepa has an acceptable toxicity profile and appears to be a reasonable option for selected BC patients.

Early postoperative radiotherapy improves progression free survival in patients with grade 2 meningioma.

BACKGROUND: Grade 2 meningiomas are a real problem in therapeutic management because of their tendency to reoccur. The most effective treatment is surgery. The role of adjuvant radiotherapy in this disease is still disputed due to its uncertain effect on progression-free survival. OBJECTIVE: To show that early adjuvant radiotherapy is an effective treatment in patients with grade 2 meningiomas. MATERIALS AND METHODS: A retrospective study was performed on all patients operated on for grade 2 meningioma in our center between 1994 and 2011. For every patient, we recorded the age at diagnosis, sex, background of neurofibromatosis type 2 (NF2) or meningiomatosis, location of meningioma, quality of tumor resection and whether the patient received early postoperative radiotherapy. These prognosis factors were studied using statistical tests. RESULTS: We included 167 patients (94 women, 73 men, sex ratio = 1.28); the mean age at diagnosis was 53.8 years. Twenty-seven patients received early adjuvant radiotherapy after surgery. Patients who received early postoperative radiotherapy had a significantly longer progression-free survival (8.2 years) than patients without radiotherapy (5.7 years, p = 0.04). In multivariate analysis, quality of tumor resection and early postoperative radiotherapy decrease the risk of recurrence of meningioma (p < 0.05). CONCLUSION: Adjuvant radiotherapy is an important therapeutic tool in the treatment of patients with grade 2 meningioma. It delays tumor progression and reduces the need for further surgery. Adjuvant radiotherapy must be considered as a treatment option in oncological multidisciplinary meetings, regardless of the quality of surgical resection.

Prognostic value and management of spinal tumors in neurofibromatosis type 2 patients.

PURPOSE: Neurofibromatosis type 2 (NF2) is a well-studied disease. Although spinal tumors are frequent, many issues concerning their prognosis and management still have to be clarified. The authors studied the clinical impact and radiological progression of spinal tumors in patients with NF2 to determine their prognostic value. METHODS: A total of 80 NF2 patients were followed in the Lille University Hospital between 1987 and 2011. Clinical, radiological and genetic data were retrospectively recorded and analyzed. Patients underwent annual cranial and spinal MRI. Both the location and size of each tumor were reported. The diagnosis of NF2 was confirmed either because the patient met the Manchester criteria or by the presence of genetic mutation. RESULTS: The mean follow-up period was 8.8 years (range 1 to 24 years; SD: ±0.8), and the mean age at diagnosis was 27.2 years (range 6 to 73 years; SD: ±1.7). Among all patients, 48 harbored spinal tumors. Twenty of them were symptomatic, and 21 were operated on. Patients with spinal tumors had a lower age at diagnosis (p = 0.02), a higher number of intracranial meningiomas (p = 0.028) and schwannomas (p = 0.03), and more nonsense and frameshift mutations (p = 0.04). CONCLUSION: Spinal tumors are common in NF2, and all patients should be regularly monitored by spinal MRI. The presence of spinal tumors seems to be a factor indicating poor prognosis. Clinical and radiological monitoring of spinal tumors could lead to early treatment both when clinical symptoms are present and in case of proven radiological evolution, maintaining a favorable functional prognosis as long as possible.

Intracranial meningiomas and neurofibromatosis type 2.

PURPOSE: In spite of the few clinical studies regarding the occurrence of intracranial meningiomas, their prognosis in neurofibromatosis type 2 (NF2) has not been accurately assessed and their management remains controversial. This study aims to compare NF2 patients with intracranial meningiomas to those without, and consequently to identify prognostic factors in attempt to improve the management of these tumors. METHODS: This retrospective study includes a total of 80 NF2 patients followed at Lille Hospital Center between 1987 and 2011. The diagnosis of NF2 was confirmed either because the patient met the Manchester criteria or by the presence of genetic mutation. Clinical, radiological and genetic data were retrospectively recorded and analyzed. Patients underwent annual cranial and spinal MRI. Both location and size of each tumor were reported. RESULTS: The mean follow-up period was 8.8 years (range 1-24 years; SD: ±0.8) and the mean age at diagnosis was 27.2 years (range 6-73 years; SD: ±1.7). Among all patients, 34 harbored intracranial meningiomas. Patients with intracranial meningiomas had a higher number of intracranial schwannomas, spinal tumors and cutaneous tumors (p < 0.05). They underwent more surgical procedures (p < 0.012). Twenty five intracranial meningiomas were surgically removed in 17 patients. The decision to perform surgery was taken in 10 cases for symptomatic tumors and in 15 cases for growing asymptomatic tumors determined by radiology. The histological analysis found a high rate of fibroblastic, transitional or grade 2 meningiomas preferentially located at the cerebri falx. CONCLUSION: Intracranial meningiomas are common in NF2. They are associated with poor prognosis factors. Clinical and radiological monitoring could lead to early treatment of these tumors both when clinical symptoms are present and in case of proven radiological evolution, and thus trying to maintain a favorable functional prognosis for as long as possible.

A Microstructure-Based Mechanistic Approach to Detect Degeneration Effects on Potential Damage Zones and Morphology of Young and Old Human Intervertebral Discs.

There is an increasing demand to develop predictive medicine through the creation of predictive models and digital twins of the different body organs. To obtain accurate predictions, real local microstructure, morphology changes and their accompanying physiological degenerative effects must be taken into account. In this article, we present a numerical model to estimate the long-term aging effect on the human intervertebral disc response by means of a microstructure-based mechanistic approach. It allows to monitor in-silico the variations in disc geometry and local mechanical fields induced by age-dependent long-term microstructure changes. Both lamellar and interlamellar zones of the disc annulus fibrosus are constitutively represented by considering the main underlying microstructure features in terms of proteoglycans network viscoelasticity, collagen network elasticity (along with content and orientation) and chemical-induced fluid transfer. With age, a noticeable increase in shear strain is especially observed in the posterior and lateral posterior regions of the annulus which is in correlation with the high vulnerability of elderly people to back problems and posterior disc hernia. Important insights about the relation between age-dependent microstructure features, disc mechanics and disc damage are revealed using the present approach. These numerical observations are hardly obtainable using current experimental technologies which makes our numerical tool useful for patient-specific long-term predictions.

Fusion and clinical outcomes of lumbar interbody fusion for low-grade isthmic spondylolisthesis.

INTRODUCTION: Low-grade isthmic spondylolisthesis (ISPL) is generally treated by circumferential fusion with interbody graft, although there is no consensus on technique. HYPOTHESIS: The various interbody fusion strategies provide satisfactory fusion rates and clinical results. METHODS: A multicenter retrospective study analyzed lumbar interbody fusion for low-grade ISPL performed between March 2016 and March 2019. Techniques comprised: circumferential fusion on a posterior or a transforaminal approach (PLIF, TLIF: n=57), combined anterior (ALIF)+posterolateral fusion (ALIF+PLF: n=60), and ALIF+percutaneous posterior fixation (ALIF+PPF: n=55). Function was assessed on a lumbar and a radicular visual analog scale (AVS-L, VAS-R), Oswestry Disability Index (ODI) and Short Form 12 (SF12). RESULTS: Among the 129 patients, 85.3% showed fusion (Lenke 1 or 2), with no significant differences between the ALIF-PLF or ALIF-PPF groups and the PLIF or TLIF groups (p=0.3). Likewise, there was no difference in fusion rates between the ALIF-PPF and ALIF-PLF subgroups (p=0.28). VAS-L (p<0.001) and VAS-R (p<0.0001), ODI (p<0.001) and SF12 physical (PCS) (p<0.01) and mental component sores (MCS) (p<0.001) all showed significant improvement at 12months. Combined approaches provided greater clinical efficacy than TLIF or PLIF for lumbar (p<0.0001) and radicular pain (p<0.05), ODI (p<0.0001) and SF12 PCS (p<0.01). At 12months, there was no clinical difference between the ALIF-PPF and ALIF-PLF subgroups. However, patents with interbody non-union (Lenke 3 or 4) had lower SF12 PCS scores (p<0.004) and VAS-L ratings (p<0.001) than Lenke 1-2 patients. CONCLUSION: Low-grade ISPL treated by circumferential arthrodesis and interbody graft showed 85.3% consolidation at 2years, with equivalent outcomes between anterior and posterior techniques. Successful fusion was associated with better clinical results. LEVEL OF EVIDENCE: IV.

Surgical management of isthmic spondylolisthesis: A comparative study of postoperative outcomes between ALIF and TLIF.

INTRODUCTION: Circumferential fusion by the anterior (ALIF) or transforaminal (TLIF) approach combined with posterior instrumentation is currently used for the surgical treatment of low-grade isthmic spondylolisthesis. But few studies have compared the clinical and radiological outcomes of various interbody fusion techniques. The objective of this study was to compare the clinical and radiological results at 2 years postoperative of two fusion techniques-TLIF versus ALIF plus posterior instrumentation-for low-grade isthmic spondylolisthesis in adults. MATERIALS AND METHODS: This was an observational multicenter study done at nine French healthcare facilities specialized in spine surgery. The inclusion criteria were minimum age of 18 years, grade 1-3 isthmic spondylolisthesis, ALIF+posterior fixation (ALIF+PS) or TLIF, minimum follow-up of 2 years. Clinical and radiological evaluations were done preoperatively and at 2 years of follow-up. A lumbar CT scan was done at 1 year postoperative to evaluate fusion. RESULTS: The cohort consisted of 89 patients (50 women, 39 men) with a mean age of 47.7±12.3 (18-79) years. The patients in the ALIF groups (n=71) had a significantly longer hospital stay than those in the TLIF group (n=18): 5.7 days versus 4.6 days (p=.04). However, their medical leave from work was significantly shorter: 31.0 weeks versus 40.7 (p=.003). Lumbar pain VAS diminished faster in the ALIF groups, with a significantly larger drop than the TLIF group in the first 3 months postoperative. Only the increase in lumbar disc lordosis was larger in the ALIF group: 11.7°±12.0° versus 6.0°±11.7° (p=.036). There was a significant correlation between the increase in global lordosis and reduction in lumbar VAS at 2 years postoperative (ρ=-0.3295; p=.021). CONCLUSION: ALIF+PS provides a faster relief of postoperative low back pain than TLIF but there are no significant clinical differences between techniques at 2 years of follow-up. Despite better restoration of disc lordosis in the ALIF+PS group, there was no difference in the restoration of global lordosis. LEVEL OF EVIDENCE: III; multicenter comparative study.