Pelvic and spinal postural changes between standing-sitting positions following lumbosacral fusion: a pilot study.

PURPOSE: Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS fusion, to detect adaptation mechanisms around fused spinal segments. METHODS: Sixteen patients aged 53.9 ± 15.9 who underwent LS fusion between L3 and S1 were extracted from the database of an ongoing prospective study. Different spino-pelvic parameters were evaluated on full spine X-rays, standing, then sitting straight. Parameters were compared pre-operative versus post-operative, and on standing versus sitting X-rays. RESULTS: Preliminary results revealed a significantly greater pre-operative pelvic tilt (PT) in sitting than standing posture, (p = 0.020) but not in post-operative (p = 0.087). After surgery, PT was lower in sitting compared to pre-operative (p = 0.034) but not in standing (p = 0.245). L4-S1 lordosis was lower in sitting than standing in pre-operative (p = 0.014) and post-operative (p = 0.021). Surgery decreased segmental lordosis above the fusion (PSL, proximal sagittal lordosis) in sitting (p = 0.039) but not in standing (p = 0.193). No significant differences in thoracic kyphosis (TK) were observed. Fusions down to L5 versus S1 showed no significant differences for PT and PSL, neither in sitting versus standing, nor pre-operative versus post-operative. CONCLUSION: Before fusion, compared to standing, PT increases in sitting straight posture (pelvic retroversion), and the lumbar spine adapts by decreasing its lordosis, mainly at L4-S1. After fusion, the segments adjacent to the instrumented section, adapt in flexion at lumbosacral and thoracolumbar junctions, i.e. just below and above (PSL). This might have mechanical implications for the occurrence of adjacent segment disease.

The mechanism in junctional failure of thoraco-lumbar fusions. Part I: Biomechanical analysis of mechanisms responsible of vertebral overstress and description of the cervical inclination angle (CIA).

PURPOSE: The purpose of the study is to describe the biomechanical theory explaining junctional breakdowns in thoraco-lumbar fusions, by taking the example of vertebral compression fractures. Also, a new angle, the cervical inclination angle (CIA), describing the relative position of the head at each vertebral level, is presented. METHODS: For the CIA, the data were collected from 137 asymptomatic subjects of a prospective database, containing clinical and radiologic informations. All the 137 subjects have an Oswestry score less than 15% and a pain score less than 2/10 and were part of a previously published study describing the Odontoïd-hip axis angle (ODHA). For each vertebral level from T1 to T12, the CIA as well as the vertical and horizontal distances was measured in reference to the sella turcica (ST), and a vertical line drawn from the ST. Average values and correlation coefficients were calculated. RESULTS: The CIA is an angle whose average value varies very little between T1 and T5 (74.9°-76.85°), and then increases progressively from T6 to T12. T1-T5 vertebra are always in line within the thoracic spine for each subject and can be considered as a straight T1-T5 segment. In addition, it was found that the vertical inclination of T1-T5 segment is correlated with the C7 slope (R 2 = 0.6383). CONCLUSION: The T1-T5 segment inclination is correlated with the C7 slope, and because the latter defines the cervical curve as previously shown, the T1-T5 segment can be considered as the base from which the cervical spine originates. Its role is, thus, similar to the pelvis and its sacral slope, which is the base from which the lumbar spine originates. The CIA along with the ODHA, which describes the adequacy of the global balance in young and elderly asymptomatic populations, are two important parameters that could help us to better understand junctional breakdowns in thoraco-lumbar fusion surgeries.

The mechanism in junctional failure of thoraco-lumbar fusions. Part II: Analysis of a series of PJK after thoraco-lumbar fusion to determine parameters allowing to predict the risk of junctional breakdown.

PURPOSE: To identify risk factors, in 12 patients with junctional breakdown (JBD) after thoraco-sacral fusions and to test a software locating maximal bending moment on full spine EOS images. METHODS: Twelve patients underwent long fusions for lumbar degenerative pathologies. Preop EOS images were compared to first postop EOS showing JBD. Parameters analyzed were: spinopelvic parameters [pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), spinosacral angle (SSA), lordosis, and kyphosis], proximal junctional angle (PJA), odontoid-hip axis angle (ODHA), and CIA. A new software estimated the location of maximum bending moment (M max) before and after JBD. RESULTS: All patients except one had a JBD located between T10 and L1, diagnosed at average follow-up of 18.58 months. JBD was a fracture in six patients, severe adjacent disc degeneration in the remaining. Average PI was 52°. PT increased, SS decreased after JBD versus preop (p > 0.05). Average PJA was 34.5°. Global lordosis (GLL), upper lordosis (ULL), L4-S1 lordosis, and thoracic kyphosis (TK) were increased (p < 0.05). Lower lumbar lordosis (LLL), was not increased postJBD (p = 0.6). SVA, SSA, ODHA, and C7 slope were not modified (p > 0.05). CIA average value decreased by 7.5% after JBD. T1-T5 alignment was correlated to C7 slope before (R 2 = 0.77075) and after JBD (R 2 = 0.85409). ODHA decreased after JBD (p > 0.05). Most JBD occurred at or one level away from preoperative M max location. CONCLUSION: This study confirms the importance of harmonious distribution of lumbar (GLL, ULL, and ILL) and thoracic curves (TK, T1-T5 segment) in thoraco-sacral fusions. All patients showed an exaggerated ULL, resulting in a posterior shift and increased lever arm at the thoraco-lumbar junction, leading to JBD.

[Adult scoliosis: surgical management]. / Scoliose de l'adulte : prise en charge chirurgicale.

Adult scoliosis is a common condition. Symptoms could be very debilitating. Surgical management requires a clear assessment of the functional impact of scoliosis, the failure of conservative treatments and precise analysis of radiological investigations (full spine views, dynamic X-rays and MRI). Surgical techniques (anterior and posterior approaches, minimal invasive techniques, osteotomies, all spine instrumentation) must be tailored to each patient. The main goals of surgery are treatment of symptoms, correction of deformity in coronal and sagittal plane and achievement of a solid fusion. Despite a high rate of complications, surgical treatment of adult scoliosis is associated with a better quality of life for patients.

La scoliose de l'adulte est une pathologie fréquente qui peut être très handicapante. La prise en charge chirurgicale, après échec des traitements conservateurs, nécessite une évaluation objective de l'impact fonctionnel de la scoliose pour le patient et une analyse systématique des investigations radiologiques (radiographie de colonne totale, clichés dynamiques et IRM). Les techniques chirurgicales (double abord, chirurgie mini-invasive, ostéotomies, longs montages) doivent être adaptées à chaque patient. Les buts principaux de la chirurgie sont de traiter les symptômes, corriger la déformation dans les plans coronal et sagittal, et obtenir une fusion solide. Malgré les complications potentielles, le traitement chirurgical de la scoliose permet d'offrir aux patients une meilleure qualité de vie.

Bone morphogenetic protein use in spine surgery-complications and outcomes: a systematic review.

PURPOSE: Because of significant complications related to the use of autologous bone grafts in spinal fusion surgery, bone substitutes and growth factors such as bone morphogenetic protein (BMP) have been developed. One of them, recombinant human (rh) BMP-2, has been approved by the Food and Drug Administration (FDA) for use under precise conditions. However, rhBMP-2-related side effects have been reported, used in FDA-approved procedures, but also in off-label use.A systematic review of clinical data was conducted to analyse the rhBMP-2-related adverse events (AEs), in order to assess their prevalence and the associated surgery practices. METHODS: Medline search with keywords "bone morphogenetic protein 2", "lumbar spine", "anterolateral interbody fusion" (ALIF) and the filter "clinical trial". FDA published reports were also included. Study assessment was made by authors (experienced spine surgeons), based on quality of study designs and level of evidence. RESULTS: Extensive review of randomised controlled trials (RCTs) and controlled series published up to the present point, reveal no evidence of a significant increase of AEs related to rhBMP-2 use during ALIF surgeries, provided that it is used following FDA guidelines. Two additional RCTs performed with rhBMP-2 in combination with allogenic bone dowels reported increased bone remodelling in BMP-treated patients. This AE was transient and had no consequence on the clinical outcome of the patients. No other BMP-related AEs were reported in these studies. CONCLUSIONS: This literature review confirms that the use of rhBMP-2 following FDA-approved recommendations (i.e. one-level ALIF surgery with an LT-cage) is safe. The rate of complications is low and the AEs had been identified by the FDA during the pre-marketing clinical trials. The clinical efficiency of rhBMP-2 is equal or superior to that of allogenic or autologous bone graft in respect to fusion rate, low back pain disability, patient satisfaction and rate of re-operations. For all other off-label use, the safety and effectiveness of rhBMP-2 have not been established, and further RCTs with high level of evidence are required.

Evidence showing the relationship between sagittal balance and clinical outcomes in surgical treatment of degenerative spinal diseases: a literature review.

The measure of radiographic pelvic and spinal parameters for sagittal balance analysis has gained importance in reconstructive surgery of the spine and particularly in degenerative spinal diseases (DSD). Fusion in the lumbar spine may result in loss of lumbar lordosis (LL), with possible compensatory mechanisms: decreased sacral slope (SS), increased pelvic tilt (PT) and decreased thoracic kyphosis (TK). An increase in PT after surgery is correlated with postoperative back pain. A decreased SS and/or abnormal sagittal vertical axis (SVA) after fusion have a higher risk of adjacent segment degeneration. High pelvic incidence (PI) increases the risk of sagittal imbalance after spine fusion and is a predictive factor for degenerative spondylolisthesis. Restoration of a normal PT after surgery is correlated with good clinical outcome. Therefore, there is a need for comparative prospective studies that include pre- and postoperative spinopelvic parameters and compare complication rate, degree of disability, pain and quality of life.

[Inter-hospital CHUV-HUG medical consensus of back pain management. Its application in care pathways within CHUV of Lausanne]. / Consensus interdisciplinaire CHUV-HUG sur la prise en charge des douleurs du dos. Son application lausannoise dans la filière du dos.

Back pain is a considerable economical burden in industrialised countries. Its management varies widely across countries, including Switzerland. Thus, the University Hospital and University of Lausanne (CHUV) recently improved intern processes of back pain care. In an already existing collaborative context, the two university hospitals in French-speaking Switzerland (CHUV, University Hospital of Geneva), felt the need of a medical consensus, based on a common concept. This inter-hospital consensus produced three decisional algorithms that bear on recent concepts of back pain found in literature. Eventually, a fast track was created at CHUV, to which extern physicians will have an organised and rapid access. This fast track aims to reduce chronic back pain conditions and provides specialised education for general practitioners-in-training.

Reliability and validity of the cross-culturally adapted French version of the Core Outcome Measures Index (COMI) in patients with low back pain.

PURPOSE: To conduct a cross-cultural adaptation of the Core Outcome Measures Index (COMI) into French according to established guidelines. METHODS: Seventy outpatients with chronic low back pain were recruited from six spine centres in Switzerland and France. They completed the newly translated COMI, and the Roland Morris disability (RMQ), Dallas Pain (DPQ), adjectival pain rating scale, WHO Quality of Life, and EuroQoL-5D questionnaires. After ~14 days RMQ and COMI were completed again to assess reproducibility; a transition question (7-point Likert scale; "very much worse" through "no change" to "very much better") indicated any change in status since the first questionnaire. RESULTS: COMI whole scores displayed no floor effects and just 1.5% ceiling effects. The scores for the individual COMI items correlated with their corresponding full-length reference questionnaire with varying strengths of correlation (0.33-0.84, P < 0.05). COMI whole scores showed a very good correlation with the "multidimensional" DPQ global score (Rho = 0.71). 55 patients (79%) returned a second questionnaire with no/minimal change in their back status. The reproducibility of individual COMI 5-point items was good, with test-retest differences within one grade ranging from 89% for 'social/work disability' to 98% for 'symptom-specific well-being'. The intraclass correlation coefficient for the COMI whole score was 0.85 (95% CI 0.76-0.91). CONCLUSIONS: In conclusion, the French version of this short, multidimensional questionnaire showed good psychometric properties, comparable to those reported for German and Spanish versions. The French COMI represents a valuable tool for future multicentre clinical studies and surgical registries (e.g. SSE Spine Tango) in French-speaking countries.

[Spinal stenosis: diagnosis and treatment]. / Canal cervical étroit: diagnostic et traitement.

Spondylotic cervical myelopathy (SCM) is a radiologic entity that can match a clinical syndrome of varying degree of severity, and results from spinal canal narrowing due to physiological degeneration of the cervical spine. Clinically, cervical spinal canal narrowing can produce minimal symptoms such as non-specific neck pain, foraminal entrapment of nerve roots, or more severe, chronic myelopathy. SCM initially manifests by signs of posterior medullary tract dysfunction with subsequent pallesthesia, resulting in gait and balance disturbance. Spasticity due to lower motoneurone impairment and incontinence may appear in later stages. Once the symptoms of myelopathy occur, functional deterioration will take place sooner or later. Surgery can then be recommended and scheduled according to the severity of functional impairment and imaging.

Effectiveness of a Group-Based Rehabilitation Program Combining Education with Multimodal Exercises in the Treatment of Patients with Nonspecific Chronic Low Back Pain: A Retrospective Uncontrolled Study.

Currently, there is no consensus on the best rehabilitation program to perform for nonspecific chronic low back pain (NSCLBP). However, multimodal exercises, education, and group-based sessions seem to be beneficial. We, therefore, launched such a treatment program and aimed to evaluate its effectiveness in improving patient health status. We retrospectively analyzed the records of 23 NSCLB patients who followed the MyBack program at La Tour hospital from 2020 to 2022 (25 sessions, 8 weeks). Patients were evaluated before and after intervention using pain on a visual analog scale (pVAS), Roland−Morris Disability Questionnaire (RMDQ), Pain Catastrophizing Scale (PCS), Tampa Scale of Kinesiophobia (TSK), and the EuroQol-5D-3L (EQ-5D-3L). Responder rates were calculated using minimal clinically important differences. Patients reported a significant reduction (p < 0.05) in the pVAS (5.3 ± 1.2 vs. 3.1 ± 1.6), RMDQ (8.8 ± 3.3 vs. 4.0 ± 3.7), PCS (24.5 ± 9.4 vs. 11.7 ± 7.9) and TSK (41.5 ± 9.2 vs. 32.7 ± 7.0). The EQ-5D-3L also statistically improved (score: 0.59 ± 0.14 vs. 0.73 ± 0.07; and VAS: 54.8 ± 16.8 vs. 67.0 ± 15.2). The responder rates were 78% for the pVAS and PCS, 74% for the RMDQ and TSK, and only 26% for the EQ-5D-3L. The MyBack program combining education with multimodal group exercises led to satisfactory clinical, functional, and psychosocial outcomes.

[Great trochanteric pain syndrome]. / Périarthrite de hanche.

Greater trochanteric pain syndrome has a high prevalence but has not been extensively studied. The diagnosis is mainly clinical, imaging techniques should be considered only in difficult cases. There are no available guidelines for the treatment. Non-steroidal anti-inflammatory drugs are often first line therapy along with a course of kinesitherapy. Local injections of corticosteroids and lidocaine are used in refractory cases. Surgical treatment should remain exceptional.

Rationale and techniques for Posterior Opening Wedge Osteotomy (POWO) in proximal junctional failure due to iatrogenic lumbar hyperlordosis.

Proximal junctional kyphosis (PJK) is a compensatory phenomenon in reaction to pathologic lumbar hyperlordosis. Inappropriate spinal curve harmony incurs risk of PJK. Postoperative failure of posterior instrumentation, with kyphosis resistant to revision surgery at the proximal junction, may be caused by excessive iatrogenic lumbar lordosis. The surgical attitude should be to decrease lumbar lordosis by posterior opening wedge osteotomy (POWO). We describe the rationale for POWO and surgical techniques at L3. The technique is illustrated by a case report at 24 months' follow-up. Based on rational analysis of the distribution of lordosis along the lumbar spine and of adaptation of the sitting position, POWO may be indicated to avoid PJK after revision surgery in adult spinal Deformation revision surgery.

[Adult scoliosis: a misknown etiology of low back pain in the elderly population]. / Lombalgie du sujet agé: le cas méconnu de la scoliose adulte.

Degenerative scoliosis is often unappreciated in all-day clinical practice, however more and more frequent in the elderly population and deserves particular attention. This article aims to provide practitioners with practical guidelines to track these patients, organise radiological assessment in accordance with clinical situations, and implement an adequate therapeutic strategy.

Perioperative intravenous low-dose ketamine for neuropathic pain after major lower back surgery: A randomized, placebo-controlled study.

BACKGROUND: Chronic pain after major lower back surgery is frequent. We investigated in adults the effect of perioperative low-dose ketamine on neuropathic lower back pain, assessed by the DN4 questionnaire, 6 and 12 months after major lower back surgery. METHODS: In this single-centre randomized trial, 80 patients received intravenous ketamine 0.25 mg/kg preoperatively, followed by 0.25 mg kg-1  hr-1 intraoperatively, and 0.1 mg kg-1  hr-1 from 1 hr before the end of surgery until the end of recovery room stay; 80 controls received placebo. RESULTS: Preoperatively, 47.4% of patients in the ketamine group and 46.3% in the placebo group had neuropathic pain; 10% and 3.8%, respectively, were using strong opioids. At the end of the infusion, the median cumulative dose of ketamine was 84.8 mg (IQR 67.4-106.7) and the median plasma level was 97 ng/ml (IQR 77.9-128.0). At 6 months, 28.8% of patients in the ketamine group and 23.5% in the placebo group had neuropathic pain (absolute difference, 5.2%; 95% CI -10.7 to 21.1; p = .607). At 12 months, 26.4% of patients in the ketamine group and 17.9% in the placebo group had neuropathic pain (absolute difference 8.5%; 95% CI -6.7 to 23.6; p = .319). CONCLUSIONS: In this patient population with a high prevalence of neuropathic lower back pain undergoing major lower back surgery, a perioperative intravenous low-dose ketamine infusion did not have an effect on the prevalence of neuropathic lower back pain at 6 or 12 months postoperatively. SIGNIFICANCE: We were unable to show any analgesic benefit of a short-term perioperative ketamine infusion as an adjuvant to multimodal analgesia in patients with a high prevalence of neuropathic lower back pain undergoing major back surgery. Based on these data, the widespread opinion that ketamine is universally analgesic across different pain conditions must be challenged. PRIOR PRESENTATIONS: Abstract presentation at the annual congress of the Swiss Society of Anaesthesiology, 2016, Basel, Switzerland. CLINICAL TRIAL NUMBER AND REGISTRY URL: Registered by Dr Christoph Czarnetzki as principal investigator on February 20, 2008 at clinicaltrials.gov (NCT00618423).

Clinical and radiological outcome of anterior-posterior fusion versus transforaminal lumbar interbody fusion for symptomatic disc degeneration: a retrospective comparative study of 133 patients.

Abundant data are available for direct anterior/posterior spine fusion (APF) and some for transforaminal lumbar interbody fusion (TLIF), but only few studies from one institution compares the two techniques. One-hundred and thirty-three patients were retrospectively analyzed, 68 having APF and 65 having TLIF. All patients had symptomatic disc degeneration of the lumbar spine. Only those with one or two-level surgeries were included. Clinical chart and radiologic reviews were done, fusion solidity assessed, and functional outcomes determined by pre- and postoperative SF-36 and postoperative Oswestry Disability Index (ODI), and a satisfaction questionnaire. The minimum follow-up was 24 months. The mean operating room time and hospital length of stay were less in the TLIF group. The blood loss was slightly less in the TLIF group (409 vs. 480 cc.). Intra-operative complications were higher in the APF group, mostly due to vein lacerations in the anterior retroperitoneal approach. Postoperative complications were higher in the TLIF group due to graft material extruding against the nerve root or wound drainage. The pseudarthrosis rate was statistically equal (APF 17.6% and TLIF 23.1%) and was higher than most published reports. Significant improvements were noted in both groups for the SF-36 questionnaires. The mean ODI scores at follow-up were 33.5 for the APF and 39.5 for the TLIF group. The patient satisfaction rate was equal for the two groups.

[Lumbar spinal stenosis: scientific evidence of surgical treatment]. / Traitement chirurgical du canal tombaire étroit: évidence scientifique en 2008.

In 2000, Nachemson and coll. published a book about modern treatment of spine related pathologies. They concluded that evidence regarding efficiency of surgical and non surgical treatments of lumbar spinal stenosis was poor. Despite this and the fact that the precise mechanism of pain is still unknown, surgical treatment of spinal stenosis, mainly consisting in a laminectomy, has made it through the years. More recently, higher quality scientific publications have brought significant evidence that surgery yields better short and long term functional results, than non surgical conservative treatment. This advantage might also compensate for possible internistic complications in a usually older and fragile population.

Optimizing Pedicle Subtraction Osteotomy Techniques: A New Reduction Plier to Increase Technical Safety and Angular Reduction Efficiency.

BACKGROUND: Pedicle subtraction osteotomy (PSO) is a technically demanding surgery. There is room for development of osteotomy reduction instruments like the one we present in this study, to better guide angular correction and closure of the osteotomy line. OBJECTIVE: To present a new surgical instrument that optimizes PSOs of the thoracolumbar spine. METHODS: Seventeen consecutive patients have been treated at 3 different European University Hospitals. All underwent a PSO of the lumbar spine to treat major sagittal imbalance. The amount of vertebral angular correction needed was calculated using the full balance integrated (FBI) method. A special plier, which allows to safely control the angular correction, was used intraoperatively. Preoperative and early postoperative global sagittal balance parameters were compared. RESULTS: The mean preoperative calculated correction angle (FBI) was 33.8°; the mean postoperative correction obtained was 32.1°. Lumbar lordosis was statistically greater than preoperatively (55.8° vs 19.4°, P < .0001). The global sagittal balance was improved, as shown by the increase of the spino-sacral angle from 122° preoperatively to 128° postoperatively (P = .0547). None of the patients had an intraoperative or early postoperative neurologic complication. There were no mechanical intraoperative complications during correction nor at the first postoperative follow-up. CONCLUSION: The advantages of the instrument are safe, precise, and efficient reduction, by a rotation of the pedicle screws close to the osteotomy line, thus avoiding collapse and lack of correction, complications usually seen with the conventional technique. Further prospective studies are needed to confirm these results.

Glucocorticoid injections for greater trochanteric pain syndrome: a randomised double-blind placebo-controlled (GLUTEAL) trial.

Small observational studies suggest that local glucocorticoid (GC) injection may be effective in the management of the greater trochanteric pain syndrome (GTPS). The objective was to perform the first randomised double-blind placebo-controlled trial to investigate the efficacy of local GC injection in the management of GTPS. The trial was conducted between November 2011 and May 2015. Inclusion criteria included lateral hip pain (LHP) for greater than 1 month, a LHP score of ≥ 4/10 and typical LHP reproduced by palpation of the greater trochanter. Participants were randomised in a 1:1 ratio to injection with a combination of local anaesthetic and GC (intervention) or injection with normal saline solution (placebo). The primary outcome of interest was the difference in pain intensity at 4 weeks post-injection between the two groups. Patients were followed for 6 months. A total of 46 patients were included. There were no significant differences between the two groups in terms of pain reduction at 1 month (p = 0.23). When including all measures in the first 4 weeks and using multilevel regression, there was a trend towards improvement in pain scores in favour of the intervention group (p = 0.08). There were no significant differences in pain scores between groups at 3 and 6 months. In the management of GTPS, local glucocorticoid injections are of no greater efficacy than injection of normal saline solution. Given the lack of long-term improvement and the potential for cortisone-related side effects, this intervention is of limited benefit.

Instrumented fusion of thoracolumbar fracture with type I mineralized collagen matrix combined with autogenous bone marrow as a bone graft substitute: a four-case report.

In order to avoid the morbidity from autogenous bone harvesting, bone graft substitutes are being used more frequently in spinal surgery. There is indirect radiological evidence that bone graft substitutes are efficacious in humans. The purpose of this four-case study was to visually, manually, and histologically assess the quality of a fusion mass produced by a collagen hydroxyapatite scaffold impregnated with autologous bone marrow aspirate for posterolateral fusion. Four patients sustained an acute thoracolumbar fracture and were treated by short posterior segment fusion using the AO fixateur interne. Autologous bone marrow (iliac crest) impregnated hydroxyapatite-collagen scaffold was laid on the decorticated posterior elements. Routine implant removal was performed after a mean of 15.3 months (12-20). During this second surgery, fusion mass was assessed visually and manually. A bone biopsy was sent for histological analysis of all four cases. Fusion was confirmed in all four patients intraoperatively and sagittal stress testing confirmed mechanical adequacy of the fusion mass. Three out of the four (cases 2-4) had their implants removed between 12 and 15 months after the index surgery. All their histological cuts showed evidence of newly formed bone and presence of active membranous and/or enchondral ossification foci. The last patient (case 1) underwent implant removal at 20 months and his histological cuts showed mature bone, but no active ossification foci. This four-case report suggests that the fusion mass produced by a mineralized collagen matrix graft soaked in aspirated bone marrow is histologically and mechanically adequate in a thoracolumbar fracture model. A larger patient series and/or randomized controlled studies are warranted to confirm these initial results.