Prospective same day discharge instrumented lumbar spine surgery - a forty patient consecutive series.

PURPOSE: Outpatient lumbar decompression surgeries have been successfully performed in France for over twenty years, earning acceptance. However, outpatient instrumented lumbar spine procedures and arthroplasties are less documented. This study aimed to evaluate the feasibility, efficiency, and safety of outpatient lumbar instrumented surgery. METHODS: A prospective single-center study involving three experienced surgeons was conducted from September 2020 to September 2021, with a minimum six-month postoperative follow-up. Inclusion criteria comprised patients aged 18 to 75 eligible for same-day discharge, undergoing single-level lumbar spinal fusion or arthroplasty via anterior or posterior Wiltse approach. The primary endpoint was assessing the percentage of successful outpatient discharges (within twelve hours), with secondary endpoints including perioperative/postoperative complications and discharge pain prescriptions in terms of frequency and severity. RESULTS: Forty patients (mean age: 44 years; 16/24 male/female ratio) underwent surgery, including 18 lumbar arthroplasties, twelve ALIF, and ten TLIF procedures. The majority of surgeries were performed at L4-L5 (18 procedures) and L5-S1 levels (22 procedures). 95% (38/40) of patients were successfully discharged within twelve hours, with only two patients discharged the following day. No postoperative hematomas, serious adverse events, or revision surgeries were noted. CONCLUSION: 95% of patients were discharged successfully within twelve hours following outpatient lumbar fusion surgery, with a 100% patient satisfaction rate. Specific technical solutions were not necessary, and oral pain relief sufficed. Patient selection and education, including early pain management, played crucial roles in complication avoidance. This study underscores the safety of outpatient instrumented lumbar spine procedures, leading to cost reduction and expedited recovery.

Conservative treatment of pediatric thoracic and lumbar spinal fractures: outcomes in the sagittal plane.

To assess sagittal plane spinopelvic balance and functional outcomes in a pediatric cohort of patients with a thoracic and/or a lumbar fracture treated conservatively. A multicentric study retrospectively reviewed radiological and functional outcomes (mean follow-up 49 months) of 48 patients (mean age 12 years) with thoracic and/or lumbar spinal fractures that occurred between 1996 and 2014. Demographic data and radiological spinopelvic parameters were analyzed. Functional outcome was evaluated by a telephone interview. First, a comparison between the initial and the last follow-up full-spine radiographs was performed for the assessment of bone remodeling and sagittal plane balance. Then, patients were classified into two groups (group 1: Risser≤2 and group 2, Risser>2) to assess the influence of skeletal maturity on the restoration of a correct sagittal balance. A total of 62% of the patients were at skeletal maturity at the final follow-up (Risser 4 and 5). Patients with a Risser grade of 2 or less had a higher remodeling potential. The mean residual local kyphosis in thoracic and lumbar fractures was, respectively, 8.2° and 8.7°. The mean thoracic global kyphosis remains stable at the last follow-up, in contrast to lumbar lordosis, which increased significantly. Sagittal plane global measurements on the basis of the C7-plumbline remained unchanged at the last follow-up. There was no change in the pelvic parameters, except for the sacral slope in the group 1 for patients with a lumbar fracture. The current study confirms a greater correction in younger patients (Risser≤2) in spinal fractures and reported that thoracic fractures have a higher remodeling potential than lumbar fracture. A local kyphosis of almost 10° remained at the last follow-up. However, no deterioration in the sagittal plane balance was found. This suggests compensatory mechanisms in adjacent structures for children and adolescents and excludes the only hypothesis of bone remodeling.

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.

Prospective study using anterior approach did not show association between Modic 1 changes and low grade infection in lumbar spine.

INTRODUCTION: The modern literature is producing a rapidly growing number of articles which highlight the relationship between infection and lumbar disc degeneration. However, the means by which samples are collected is questionable. Posterior approach surgery is not free from skin contamination. The possibility of intraoperative contamination of disc biopsies cannot be excluded. OBJECTIVE: The objective of this study was to determine if an association existed between lumbar disc degeneration and chronic infection of the intervertebral disc. MATERIALS AND METHODS: 313 patients (186/127, F/M) with chronic low back pain secondary to degenerative disc disease which was resistant to medical treatment were included in a single-centre prospective study. All underwent a lumbar anterior video-assisted minimally invasive fusion or disc prosthesis in L4-L5 and/or L5-S1 via an anterior retroperitoneal approach. The patients MRI scans demonstrated in Pfirrmann's classification grade IV or V disc degeneration; 385 disc drives were taken. In terms of Modic changes, 303 Modic 1, 58 Modic II and 24 absence of Modic change, respectively. All underwent intraoperative biopsy, performed according to a strict aseptic protocol. The biopsies were then cultured for 4 weeks with specialised enrichment cultures and subjected to histopathological analysis. RESULTS: The mean age was 47 ± 8.6 years sterile cultures were obtained in 379 samples (98.4%) and 6 were positive (1.6%). The cultured bacteria were: Propionibacterium acnes (n:2), Staphylococcus epidermidis (n:2), Citrobacter freundii (n:1), and Saccharopolyspora hirsuta (n:1). Histopathological analysis did not demonstrate any evidence of a neutrophilia. There were no delayed or secondary infections. DISCUSSION AND CONCLUSION: Unlike the posterior approach where contamination is common, the anterior video-assisted approach allows a biopsy without skin contact. This approach to the spine is the most effective way to eliminate the risk of contamination. Our results confirm the absence of any relationship between infection and disc degeneration. We suggest that the 6 positive samples in our study may be related to contamination. The absence of infection at 1-year followup is an additional argument in favour of our results. In conclusion, our study shows no association between infection and disc degeneration. The pathophysiology of disc degeneration is complex, but the current literature opens new perspectives.

Post-trauma scoliosis after conservative treatment of thoracolumbar spinal fracture in children and adolescents: results in 48 patients.

PURPOSE: Authors examined a case series of patients younger than 18 years old who had sustained a traumatic thoracolumbar spine fracture to evaluate radiological and clinical findings of coronal spinal balance, after conservative treatment. METHODS: From 1996 to 2014, a tricentric cohort of 48 patients with an average age of 12 years was radiographically reviewed at 50 months. Cobb angle of fractured vertebra and regional Cobb angle were measured both at baseline and follow-up. Analyses were done according to initial Risser grade, number of fractures and level of injury. RESULTS: There was a total of 11 scoliosis. In group with Risser grade 3 or above, with a single vertebral fracture and lumbar fracture, final regional Cobb angle was statistically higher than initial regional Cobb angle. CONCLUSIONS: The prevalence of scoliosis in our population is higher than those of idiopathic scoliosis; Risser grade 3 or above, lumbar fracture and a single fracture seem to account for more severe coronal deformation.

Role of a collagen membrane in adhesion prevention strategy for complex spinal surgeries.

PURPOSE: Following lumbar spine surgery, postoperative complications can appear, including epidural adhesions. The formation of fibrosis around the dura mater can, on the one hand, lead to compression of the nerve roots with recurrent radicular pain and, on the other hand, can increase the risks of specific complications at spinal re-intervention (haematomas and dural breaches). The aim of this prospective monocentric study was to assess the safety of a new collagen antiadhesion membrane in vertebral osteotomy surgery where scar tissue and adhesions are important. METHODS: Twenty-six patients consecutively operated for lumbar posterior subtraction osteotomy with implantation of a collagen-based anti-adhesion membrane were evaluated. Membrane tolerance was evaluated at the short and midterm during the regular follow-up. RESULTS: At six months' follow-up, postoperative pain [visual analogue scale (VAS)] and disability (Oswestry Disability Index score) were significantly reduced 33.1 and 43.1%, respectively. These results were confirmed at 12-months' follow-up, with a decrease in pain of 39.9% and in disability of 49.3%. Amongst the observed postoperative complications was neither spinal fluid leak nor durotomy. Presence of the membrane was not related to complications. Two patients required further surgery for infection and nonunion at the osteotomised level. Adhesions to the dura mater were limited and thin, facilitating exposure. CONCLUSIONS: This study shows good tolerance of the collagen based membrane for spinal osteotomy and its satisfactory use for preventing postoperative epidural adhesions. Good surgical practice associated with an anti-adhesion barrier may decrease fibrosis formation and improve postoperative functional results.

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.

Lumbo-pelvic related indexes: impact on adult spinal deformity surgery.

PURPOSE: Lumbo-pelvic indexes appeared recently in the literature taking advantage from the relationship between pelvic incidence (PI) and lumbar lordosis (LL). Schwab proposed to subtract LL from PI (PI-LL) as Boissière proposed the lumbar lordosis index (LLI), which is the ratio between LL and PI (LL/PI). Both indexes have been described to weight LL by a constant parameter not affected by degenerative processes, the PI. The aim of this study is to evaluate these parameters in adult spinal deformity (ASD) by analyzing their relationship with spinal malalignment and vertebral osteotomies. METHODS: Two groups of patients with an ASD were realized; an adult scoliosis group (n = 78) and a postoperative flat-back syndrome group (n = 20). In the adult scoliosis group, 28 patients underwent an osteotomy [pedicle subtraction osteotomy (PSO) or Smith Petersen osteotomy] and 50 patients were corrected by posterior fusion without osteotomy. In the postoperative flat-back syndrome group all patients underwent a PSO. All patients had preoperative and postoperative full spine EOS radiographies to measure spino-pelvic parameters. The lack of lordosis was calculated, after prediction of theoretical LL from Legaye's formula, by subtracting measured LL to theoretical LL. Correlation analysis between the different parameters was performed. RESULTS: Both lumbo-pelvic parameters highly correlated with spinal malalignment (r = 0.97 for PI-LL and r = -0.97 for LLI for total patients) and were highly predictive of a spinal osteotomy performance (r = 0.88 for PI-LL >28° and r = 0.94 for LLI <0.5). Sagittal vertical axis (r = 0.67) and pelvic tilt (r = 0.64) correlated moderately with spinal malalignment for total patients. The LLI was more correlated with spinal osteotomies in the adult scoliosis group (r = 0.86 for PI-LL >28° and r = 0.94 for LLI <0.5), as Schwab's index was more precise to predict osteotomies in the postoperative flat-back syndrome group (Youden index = 0.95 for PI-LL >28° vs 0.90 for LLI <0.5). CONCLUSIONS: This study highlights the necessity to considerer spinal malalignment with lumbo-pelvic indexes as they appear to be highly correlated with lack of LL. They can be used as mathematical tools to detect spinal malalignment in ASD and guide the surgeon's decision of realizing a vertebral osteotomy for ASD sagittal correction. They can be used as well for the interpretation of clinical series in ASD.

Global analysis of sagittal spinal alignment in major deformities: correlation between lack of lumbar lordosis and flexion of the knee.

INTRODUCTION: It has become well recognised that sagittal balance of the spine is the result of an interaction between the spine and the pelvis. Knee flexion is considered to be the last compensatory mechanism in case of sagittal imbalance, but only few studies have insisted on the relationship between spino-pelvic parameters and lower extremity parameters. Correlation between the lack of lumbar lordosis and knee flexion has not yet been established. MATERIALS AND METHODS: A retrospective study was carried out on 28 patients with major spinal deformities. The EOS system was used to measure spinal and pelvic parameters and the knee flexion angle; the lack of lumbar lordosis was calculated after prediction of lumbar lordosis with two different formulas. Correlation analysis between the different measured parameters was performed. RESULTS: Lumbar lordosis correlated with sacral slope (r = -0.71) and moderately with knee flexion angle (r = 0.42). Pelvic tilt correlated moderately with knee flexion angle (r = 0.55). Lack of lumbar lordosis correlated best with knee flexion angle (r = 0.72 and r = 0.63 using the two formulas, respectively). CONCLUSION: Knee flexion as a compensatory mechanism to sagittal imbalance was well correlated to the lack of lordosis and, depending on the importance of the former parameter, the best procedure to correct sagittal imbalance could be chosen.

Polytetrafluoroethylene membrane (Gore Preclude Vessel Guard) for vessel protection during anterior lumbar surgery: a preliminary study in pigs.

STUDY DESIGN: The effects of implanting a polytetrafluoroethylene (PTFE) membrane (Gore Preclude Vessel Guard, WL Gore and Associates, Flagstaff, AZ) during anterior lumbar surgery were studied in a pig model. OBJECTIVE: We investigated whether placement of a PTFE membrane between the great vessels and anterior surface of the lumbar spine would minimize adhesions. SUMMARY OF BACKGROUND DATA: Anterior lumbar procedures continue to increase, as do revision operations. Anterior approaches remain challenging, however, because of the considerable risk of vascular injury. The risk is especially high with revision procedures because of the presence of adhesions that can hinder visualization and mobilization of vessels. Use of an anti-adhesion barrier may decrease the rate of vascular complications associated with revision surgery. METHODS: Three spinal levels in 3 pigs were subjected to either discectomy, creation of a hole in the disc, or disc exposure only. In 5 of the 9 levels, a PTFE membrane was then implanted over the disc; the other 4 levels were controls. Spine segments were obtained 12 weeks later, and the tenacity of adhesions (scale of 0 to 4) and percentage of disc space covered by adhesions were assessed. The specimens were also studied histologically. RESULTS: Mean values for adhesion tenacity were 2.75 for control spinal levels and 0.4 for levels with a PTFE membrane (P=0.008). Mean values for adhesion coverage were 81% for control disc spaces and 15% for spaces with a PTFE membrane (P=0.008). Histologic studies showed minimal adhesions, lack of an inflammatory reaction, and vascularized connective tissue between PTFE membranes and the vena cava. CONCLUSIONS: In a pig model, implantation of a PTFE membrane during anterior lumbar surgery decreased the tenacity and amount of adhesions observed at necropsy. Studies of the efficacy and safety of the PTFE membrane in clinical anterior lumbar surgery are warranted.

Hybrid construct for two levels disc disease in lumbar spine.

Prospective study. To study the validity of Hybrid construction (Anterior Lumbar Interbody Fusion) ALIF at one level and total disc arthroplasty (TDA) at adjacent, for two levels disc disease in lumbar spine as surgical strategy. With growing evidence that fusion constructs in the treatment of degenerative disc disease (DDD) may alter sagittal balance and contribute to undesirable complications in the long-term, total disc arthroplasty (TDA) slowly becomes an accepted treatment option for a selected group of patients. Despite encouraging early and intermediate term results of single-level total disc arthroplasty reported in the literature, there is growing evidence that two-level arthroplasty does not fare as well. Hybrid fusion is an attempt to address two-level DDD by combining the advantages of a single-level ALIF with those of a single-level arthroplasty. 42 patients (25 females and 17 males) underwent Hybrid fusion and had a median follow-up of 26.3 months. The primary functional outcomes were assessed before and after surgery with Oswestry Disability Index and the visual analogue score of the back and legs. Patients were divided into four groups according to the percentage improvement between preop and postop ODI scores. A total of 42 patients underwent a hybrid fusion as follows: 35 L5-S1 ALIF/L4-5 prosthesis, 3 L4-5 ALIF/L3-4 prosthesis, 2 L5-S1 ALIF/L4-5 prosthesis/L3-4 prosthesis, 1 L5-S1 prosthesis/L4-5 ALIF, and 1 L5-S1 ALIF/L4-5 ALIF/L3-4 prosthesis. At 2-years clinical outcomes, mean reduction in ODI is 24.9 points (53.0% improvement compared to preop ODI). The visual analogue score for the back is 64.6% improvement. At 2-year clinical outcomes, Hybrid fusion is a viable surgical alternative for the treatment of two-level DDD in comparison with two-level TDA and with two-level fusion.

Lumbar decompression and fusion in elderly osteoporotic patients: a prospective study using less rigid titanium rod fixation.

TYPE OF STUDY: A 2 to 4-year clinical and radiologic prospective study was conducted for 39 patients over the age of 65 treated by lumbar arthrodesis. OBJECTIVES: Evaluate the quality of lumbar arthrodesis results in elderly patients, in which the bone osteoporosis (poor quality of the spine's anatomic components) and general factors (frequent comorbidity) are likely to make this surgery difficult if not dangerous and evaluate a dedicated instrumentation for osteoporotic bone. MATERIALS AND METHODS: Thirty-nine patients over 65 years of age (average 73 y) underwent arthrodesis surgery in 2001 and 2002 and were followed for at least 2 years. The instrumentation used (Equation, Medtronic, Memphis, USA) was selected for its mechanical properties adapted for bone of poor mechanical quality. The clinical analysis was based on Oswestry, Visual Analog Scale, and Japanese Orthopaedic Association scores. Radiologic results were evaluated on standard anteroposterior, lateral, and 3/4 radiographs, and computed tomography scans if necessary. RESULTS: All the patients were followed for 2 to 4 years. Clinical analysis confirmed a very satisfactory progression of the clinical parameters such as lumbar and radicular pain, and the results were maintained between the first and second years and at last follow-up. No serious general complication or need for reoperation was seen in this series. On x-rays, 35 grafts appear to have fused. The anchors did not come out nor did the instrumentation come apart. On the other hand, 2-year radiographs revealed that 2 screws and 2 rods had failed, but this did not affect correction in the 4 completely asymptomatic patients. These 4 cases are considered stable at last follow-up. CONCLUSIONS: Arthrodesis for elderly patients will undoubtedly increase in the coming years. The conditions for this surgery are different than those for younger patients and it is desirable to try to provide reliable surgical techniques and solutions regarding options for instrumentation and overall perioperative care for these fragile patients. Dedicated instrumentation for osteoporotic bone seems to allow good clinical outcomes.

Video-assisted ALIF with cage and anterior plate fixation for L5-S1 spondylolisthesis.

INTRODUCTION: Spondylolysis and spondylolisthesis grade 0, 1, and 2 are mainly asymptomatic but with aging process and different factors some back pain can occur and lead to chronic low back pain. The conservative treatment with physiotherapy and steroid injection is the gold standard but in some cases is not efficient enough and a surgical treatment is proposed. OBJECTIVES: The goal of this study is to propose a new technique to treat grade 0, 1, and 2 spondylolisthesis with an anterior video-assisted fusion and stabilization. METHODS: Twenty patients with chronic low back pain since more than 2 years and resistant to conservative therapy were included in this protocol. Clinical signs and radicular pain were noted. They were evaluated preoperatively and postoperatively until the last follow up using Oswestry score and visual analog score (VAS) for leg and back pain. X-rays showed grade 0 (8 cases), 1 (10 cases), and 2 (2 cases) spondylolisthesis according to Meyerding classification with disc collapse (bulging disc). MRI showed in all cases a disc degeneration with at least black disc and/or endplates changes with Modic I or II. All patients were operated using an anterior video-assisted retroperitoneal approach, with discectomy and fusion using an anterior impacted cage filled with autologous cancellous bone from the iliac crest and an anterior fixation with a triangular plate (Pyramid, Medtronic, Memphis). The follow up at 3, 6, 12, and 24 months was done with clinical and radiologic evaluation. In case of problem a computed tomography scan was performed. RESULTS: There were 11 women and 9 men, with and average age of 39 years old and a BMI of 25.6. All spondylolistheses occurred at level L5. The average slippage was 19%. All L5S1 discs were black, 8 had a Modic I changes in the endplates and 2 had Modic II. The shape of L5 vertebra was abnormal (trapezoidal) in 7 cases. All anterior approaches were performed without vascular, urologic, or digestive complication. Blood loss was inferior to 100 mL. All patients had a soft brace for 8 weeks postoperatively. There was no retrograde ejaculation for the 9 men and no sexual dysfunction reported by the women. One patient had no pain relief and was reoperated for posterior pedicular screw fixation. It was obvious that there was a pseudarthrosis even after the posterior fixation and an anterior transperitoneal revision was performed with the removal of the interbody device and iliac crest bone graft packing alone. A propioni bacterium acnes germ was found responsible for the anterior nonunion. This revision surgery with antibiotics treatment was successful. One of the patients with grade 2 had an additional posterior screw fixation with a minimally invasive pedicle screw system (Sextant, Medtronic, Memphis). Nineteen patients had a good fusion at 2 years follow-up (95%), mean Oswestry score improved from 74% preoperative to 21% postoperative at the last follow-up. Visual analog score (VAS) for back pain improved from 6.5 to 2.7 and VAS for leg pain improved from 6.2 to 3.4. Satisfaction rate was 90%. All active patients except two, were back to work at an average of 5.5 months (6 wk to 1 y). The 2 patients still not working were the nonunion and a work compensation. CONCLUSIONS: The results of this technique compare favorably with posterior stabilization and fusion (posterior lumbar interbody fusion and postero-lateral fusion) reported in the literature. Unlike posterior lumbar interbody fusion, however, it seems that the complication rate due to the approach is much lower, the fusion rate is similar. Grade 2 SPL is the limitation of the technique. The main advantage of the technique is to avoid posterior muscle damage and a quick recovery with no blood loss. Preservation of adjacent level disease can be assessed only after long-term follow-up.

Acute knee trauma: role of ultrasound.

The purpose of this study was to determine the diagnostic accuracy of high spatial resolution ultrasonography (US) in the detection of lipohemarthrosis of the knee and to evaluate this sign as criteria of intra-articular fracture. Forty-eight patients with clinical suspicion of knee fracture were prospectively examined by conventional radiography, sonography examination and computed tomography (CT) within 48 h after trauma in order to depict direct (fracture line) and indirect (lipohemarthrosis) signs of intra-articular fracture. Lipohemarthrosis was defined as a multi-layered collection in the subquadricipital recess. CT was considered as the gold standard for both direct and indirect fracture criteria. CT imaging showed direct signs of intra-articular fracture in 31 patients (65%). Among these patients, 30 (97%) had a lipohemarthrosis. Conventional radiographs showed intra-articular fracture in 26 patients (54%). Among these, 18 (69%) had a lipohemarthrosis. Sonographic examinations could not depict any direct sign of intra-articular fracture but showed a lipohemarthrosis in 29 (93%) of patients with proven fracture via CT. This allowed the depiction of four out of five occult knee fractures. The sensitivity, specificity, positive predictive value, negative predictive value of sonography for the diagnosis of lipohemarthrosis was 97, 100, 100 and 94%, respectively, compared with 55, 100, 100 and 55% with conventional radiographs. Using lipohemarthrosis as criterion of fracture, the sensitivity, specificity, positive predictive value and negative predictive value of sonography for early detection of intra-articular knee fractures was 94, 94, 97 and 89%, respectively, compared with 84, 88, 93 and 75% with conventional radiographs. We concluded that, by showing lipohemarthrosis in the subquadricipital recess, high-resolution sonography is a reliable and accurate technique for the evaluation of intra-articular knee fractures.

Biological performance of a new beta-TCP/PLLA composite material for applications in spine surgery: in vitro and in vivo studies.

The objective of this research was to carry out an in vitro and in vivo study of the biological performance of PLLA/beta-TCP composite materials, to estimate the scope of their potential applications in bone surgery. Samples with increasing beta-TCP (0-60% w/w) contents were processed by injection molding. The in vitro study consisted of an evaluation of inflammatory potential by assaying the IL-1alpha secreted by monocytes, and then cell proliferation (counting) and phenotype expression (PAL and I collagen) in human osteogenous cells. The in vivo study was carried out using cylindrical implants of composite materials composed of composite materials containing 0 or 60% beta-TCP and pure beta-TCP, respectively. The implants were inserted in femoral sites in rabbits, using the Kathagen protocol. Each animal received a 60% implant, with either a 0 or a 100% implant in the contralateral femur, so that the materials could be compared with one another. Five animals were examined for each material and implantation period, giving a total of 30 animals. This study showed that adding increasing percentages of beta-TCP to a lactic acid polymer matrix stimulated the proliferation of human osteogenous cells and synthesis of the extracellular bone matrix in a dose-dependent manner. In vivo results indicate that, in comparison with pure PLA, tricalcium phosphate-containing composite materials had faster degradation kinetics, caused less inflammatory reaction, and promoted contact osteogenesis. The composite material containing 60% beta-TCP demonstrated a similar performance to pure tricalcium phosphate bone grafts in terms of osteogenesis, and is apparently compatible with the production of intra-osseous implants for situations representing high levels of mechanical strain.

Influence of facet and posterior muscle degeneration on clinical results of lumbar total disc replacement: two-year follow-up.

OBJECTIVE: There has been little analysis assessing the correlation between the clinical functional result of total disc replacement and the arthrosis of the posterior facets or the fatty degeneration of the spinal muscles. However, such knowledge is essential for understanding the long-term outcome of devices in functional terms. This prospective study reports the outcome of 64 Maverick (Medtronic) devices implanted between January 2002 and November 2003. RESULTS: Oswestry score preoperatively and at 2-year follow-up was 43.8 and 23.1, respectively (P < 0.05). Low back pain improved from a mean Visual Analog Scale (VAS) score of 7.6 +/- 1.7 preoperatively to 3.2 +/- 1.8 at 2 years. Mean VAS leg pain score decreased from 3.9 to 2.1 at 2 years (P < 0.05). Facet osteoarthritis grade 1 or 2 did not influence outcome (P = 0.82). On the other hand, muscle degeneration of grades 1 and 2 led to a better outcome than grades 3 and 4 (P = 0.006). CONCLUSIONS: This is the first study showing that a semiconstrained implant with a fixed posterior center of rotation can be implanted with grade 1 and 2 facet arthrosis with a good clinical outcome. This seems to confirm previous work showing that a posterior center of rotation lightens the load on the facets. This is also the first study to show a relationship between muscle fatty degeneration and clinical results since the greater the amount of fat, the less satisfactory the result. These promising midterm results must be confirmed by further studies.