Jean Charles Le Huec

Nucleus Replacement With the DASCOR Disc Arthroplasty Device: Interim Two-Year Efficacy and Safety Results From Two Prospective, Non-Randomized Multicenter European Studies

Study Design. A prospective, nonrandomized multicenter study of lumbar disc nucleus replacement using the DASCOR Disc Arthroplasty Device. An interim analysis of clinical results is presented, obtained from European patients enrolled in 2 studies. Objective. To determine the safety and efficacy of the DASCOR Device for the treatment of symptomatic single-level degenerative disc disease (DDD). Summary of Background Data. Patients suffering from DDD have been limited to a choice between nonoperative therapies or invasive surgical treatments such as total disc replacement or spinal fusion. The DASCOR Device was developed to provide an alternative treatment with a less invasive surgical intervention. Methods. A total of 85 patients from 11 European centers were enrolled in 1 of 2 studies between February 2003 and July 31, 2007. Data were collected before surgery and after surgery at 6 weeks and at 3, 6, 12, and 24 months. The clinical outcome measures were obtained from the Visual Analog Scale (VAS) for back pain, the Oswestry Disability Index (ODI), radiographic assessments, and records of analgesic medication use. Results. Mean VAS and ODI scores improved significantly after 6 weeks and throughout the 2 years. Radiographic results demonstrated, at a minimum, maintenance of disc height with no device expulsion and, despite Modic-Type 1 changes, no subsidence. Fourteen patients had serious adverse events including device explants in 7 patients (7 of 85), in which the main complication was resumed back pain after time. Patients’ rate of analgesic medication decreased dramatically over time, with all patients experiencing significant improvements after 3 months and nearly no analgesic medication or narcotic drug use at 2 years. Conclusion. The interim outcomes showed significant improvements in mean ODI and VAS scores. The results of these European studies suggest that the DASCOR Device may be a safe and effective less-invasive surgical option for patients with DDD.

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.

New Composite Material: PLLA and Tricalcium Phosphate for Orthopaedic Applications-In Vitro and In Vivo Studies (Part 1)

This study showed that adding increasing percentages of β–TCP to a lactic acid polymer matrix stimulated the proliferation of human osteogenous cells and synthesis of the extra-cellular 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 % β-ʿTCP 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 obtaining bone fusion or healing. Further studies are necessary to evaluate the ability of such a composite material to retain sufficient mechanical strength overtime for providing safe correction or stabilization of the implanted bone fragments.

Clinical Results of a New Resorbable Composite Material for Cervical Cage: 6 Years’ Follow-up (Part 2)

Efficiency of corticocancellous autologous bone grafts in cervical interbody fusion has been widely reported since Smith and Robinson or Cloward. Depending on the studies, 70–96 % of the patients develop good or excellent results. However, the use of autologous grafts induces a second operation, generally on the iliac crest, and may be associated with an important morbidity. Moreover, such complications as long term pain syndrome, femorocutaneus nerve damage, infection or secondary fracture has been reported. In order to prevent such risks, different bone substitutes are nowadays available. Natural ones like allografts or xenografts have been studied since decades. With a cancellous-like architecture, their macroscopical structure can help bone ingrowth and lead to satisfying results with regards to bone fusion, both on animal models or humans. But these natural bone grafts still represent a microbiological risk, like AIDS, hepatitis or non-conventional disease transmission. For these reasons, we preferred synthetic materials when choosing a bone substitute. Elaborated from pure chemical compounds, such materials seemed safer to us. Among the family of synthetic materials, calcium phosphate compounds like hydroxylapatite (HA) are probably better known. Intensively studied over the last 20 years, such compounds are biocompatible. In a porous form, they facilitate bone cells penetration and lead, as well as allografts or heterografts, to bone healing and fusion with surrounding bone.

Report of One Year Follow Up of Patients after TLIF using a 3-Dimensional Expandable Cage for Lumbar Fusion with Lordotic Correction

Introduction The use of a new 3 dimensional (3D) expandable cage for TLIF was extensively studied in biomechanical tests, cadaver specimens and preliminary clinical series. A wide footprint is achieved through a one side portal due to the articulated implant positioned in the anterior third of the disc space. The lordotic correction is accomplished due to the expansion of the device in place assisting on the overall sagittal alignment. Previous reports presented showed initial promising clinical results. One year follow up of the first 10 patients is now reported. Material and Methods Ten patients were included in a 12 months prospective review after a TLIF using a 3D Titanium alloy FLXFit expandable cage. The procedure was done for a single or two level fusion with positioning of the cage under fluoroscopy and expansion for disc space height and lordotic correction. All patients were supplemented with posterior instrumentation. Primary clinical outcomes were evaluated by preoperative, 6 months, 12 months and last follow-up visual analog scale (VAS) and the Oswestry Disability Index (ODI) scores. Complications and neurological impairment were recorded. Radiographic assessment of pre and post-operative results was performed with measurement of correction achieved in the frontal and sagittal planes with EOS imaging technology avoiding any distortion on X-Rays. All patients underwent CT scan control at 12 months. Results All ten patients underwent a successful one or two levels instrumented TLIF without any permanent neurological, vascular or visceral complication. The 3D cage implantation provided lordosis augmentation of 8° (± 2.1°) allowing restoration of the sagittal alignment according to pre-op planning. On early post-op CT scans, good footprint and no endplate violation were shown with no cage subsidence. Clinical outcomes showed significant improvement for both VAS and Oswestry scores (P < 0.05), 3.7 (± 2.9) and 31% (±11) respectively. Similar outcomes were found at 12 months: no cage subsidence, VAS and Oswestry scores (P < 0.05), 3.5 (± 2.7) and 28,4% (±12) respectively. Conclusion Lumbar interbody fusion using this new 3D expandable cage provided correction of the lordosis in a shorter and effective surgical procedure. A wide footprint well positioned cage, with customized height and angular correction achievement assured an optimal load transmission and biomechanical environment for fusion. Initial clinical results were followed with successful clinical outcomes in all patients.

A Multicenter Prospective Randomized Controlled Clinical Trial to Evaluate the Effectiveness and Safety of a Standalone Percutaneous Interspinous Spacer versus Decompressive Surgery in Degenerative Lumbar Spinal Stenosis with Neurogenic Intermittent Claudication

Introduction The objective of this study is to show that a minimally invasive percutaneous IPD is safe and non-inferior to SDS with regards to clinical outcomes in patients suffering from Degenerative Lumbar Spinal Stenosis with NIC (Neurogenic Intermittent Claudication), relieved by flexion. (Design: Multicenter international randomized controlled trial) Methods One hundred and sixty three patients enrolled by 19 sites across 10 countries (mean age 65 ± 11 years, 51% female, mean duration of leg symptoms 2.5 years) were randomly assigned to IPD or SDS group and are followed until 24 months. Physical function, symptom severity and patient satisfaction were assessed by Zurich Claudication Questionnaire (ZCQ) at baseline, 14days, 6 weeks, 6 months and 12 months follow-ups. Leg, buttock/groin and back pain were assessed by VAS scores. SF-36v2 questionnaire was used to assess quality of life. In addition, physical examination data was collected at all-time points. Percentage of re-operations at index level at follow-up was determined. (Trial registration NTC00905359) Results ZCQ physical function mean percentage change from baseline to 12 months (primary outcome variable) decreased equally and without statistically significant difference over all points in time for IPD and SDS group (respectively, −32 ± 32%, −37 ± 23%, p = 0.158, CI −5, +15). As for secondary outcomes the IPD group showed lower mean surgical time and mean blood loss (respectively, 24 ± 11 minutes and 6 ± 10 ml, p < 0.001) compared with the SDS group (70 ± 39 minutes and 157 ± 145 ml, p < 0.001). Symptom severity improved in both groups equally (−31 ± 27%, −36 ± 25%, p = 0.140, CI −4, +14). No differences in patient satisfaction were observed. VAS leg pain score improved with 59% for the IPD and 66% for the SDS group from baseline to 12 months follow-up. SF-36 v2 physical and mental aggregated score improved equally over time for both treatment groups. At 12 months, 47 SAEs were reported, in 36 patients. Re-operations at index level occurred in 9% of the patients in the IPD group and in 7% in the SDS group. In 6 patients the IPD was explanted. Conclusions This study confirms two prior recent RCTs. Implantation of an IPD as well as open decompression achieve both equally satisfying results in patients with NIC. Both seem to be appropriate procedures with an advantage in some secondary outcomes for IPDs. So far the significantly higher reoperation rate for IPDs could not be confirmed in this study, which opens a window of indication in a subset of patients with NIC, i.e., those with cardiac or other comorbidities.

Validation of Positioning, Lordotic Correction and Lack of Endplate Damage When using a New Expandable Articulated Lumbar Intervertebral Fusion Cage; A Cadaver Study

Introduction Intervertebral lumbar fusion cages became nowadays a useful tool by preserving disc space height, retaining proper tension of ligaments and providing better anterior column support with contained bone graft. Expandable cages, a new available category, help to approach the disc space with less invasive techniques adjusting its height to the local anatomy. Theres need in using cages with the widest footprint, able to expand to increase disc height up to normal correcting lordotic alignment, particularly at L4–5 and L5-S1 levels, without damaging the endplates in the process and reducing pre-stress of posterior instrumentation. A 3-dimensional articulated expandable cage was tested in cadavers to verify: its effect on positioning in the disc space, by navigating its two-linked segments in the transversal plane; its expansion without endplate violation and its resultant lordotic correction in the sagittal plane. Material and Methods Five fresh-frozen human cadaver specimens were randomly assigned to two surgeon teams for discectomy and implantation of this new expandable titanium-alloy FLXfit cage through one-sided TLIF approach using fluoroscopy and standard spine instrumentation. No facetectomy or posterior instrumentation were performed. Every cadaver underwent a two level procedure, L2–3 and L5-S1. Each cage allowed a lordotic angled expansion of up to 10° with a dedicated cage tool. After implantation, all specimens were dissected and disc spaces incised for evaluation of positioning and endplate condition as result of expansion. Final positioning was documented with X-rays and lordotic angles were measured. Lordotic increments were calculated by level from pre and post-operatory measurements. Each surgeon rated his experience in designated questionnaires. Results Ten expandable cages of various sizes were implanted according to trial measurements obtained during the procedure. Surgeons successfully inserted, positioned and expanded the cages based on surgical technique. The procedure was reported as being easy to perform by the surgeons. Implant positioning was consistently accomplished in the anterior two-thirds of the disc space near the apophyseal ring due to the articulated feature covering a large footprint. Gradual cage angular expansion was performed till the maximal degree allowed in all cases, customized to each level treated. Analysis of dissected cadavers revealed an effective discectomy with preservation of the annulus except the entry portal. No endplate violation was reported in all specimens. On lateral X-rays, lordotic increment from preoperative values was significantly higher in L2–3 discs, being 7.8°±2.2 (from 5 to 10°). On L5-S1 discs the increase was 4.8°±1.3 (from 4 to 7°). The overall added lordotic correction was on average 12.6°±2.5 per spine. Conclusion The use of 3-dimensional expandable cages in this cadaver study allowed better endplate bone contact with a well-fitted adjustment, according to the level treated without endplate damage. Lordosis correction was achieved differentially depending on the level and original values of alignment. Added up individual correction was shown on overall sagittal correction using two cages, which would be likely enhanced with facet resection and posterior instrumentation. The use of well positioned, large footprint, expandable lordotic correcting cages may lead to a more biomechanically balanced results in lumbar spine fusion.