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Vincent Arlet

Publications and source records attributed to Vincent Arlet.

At least 19 recordsLinked to original sources
PubMed2006

A novel "four-rod technique" for lumbo-pelvic reconstruction: theory and technical considerations.

STUDY DESIGN: Surgical technique with case example. OBJECTIVE: To report on a novel technique that allows for the placement of 4 separate longitudinal rods across the lumbo-pelvic junction. SUMMARY OF BACKGROUND DATA: Despite advances in surgical techniques and instrumentation, lumbo-pelvic fixation remains a significant challenge. Fusions to the pelvis create long lever arms and generate high forces across the lumbosacral junction, resulting in high rates of screw pullout and implant fracture. In the attempt to achieve better bony fixation, techniques described include the use of bone cement, hydroxyapatite, and expandable screws. Although this process has decreased the incidence of screw pullout, it has not addressed the problem of rod fracture at the lumbo-pelvic junction. METHOD: There are 4 separate longitudinal rods placed across the lumbo-pelvic junction that couples proximal lumbar screw anchors to 4 separate pelvic fixation points. Proximal lumbar fixation anchors are based on alternating Roy-Camille "straight ahead" screws and Magerl "lateral to medial converging" pedicle screws. There are 4 distal pelvic fixation anchors used based on 1 pair of Galveston-like screws and 1 pair of proximal iliac wing screws. RESULTS: Early results of both ex vivo and in vivo reconstruction show that careful insertion of the lumbar and pelvic screws allows for divergent placement of the pedicle screw heads in a manner that 2 longitudinal rods can be placed per side, resulting in a total of 4 longitudinal rods across the lumbo-pelvic junction. Selection of cross-links in various combinations allows for additional axial and torsional stability, depending on the desired reconstruction. CONCLUSION: Longer follow-up is necessary, and biomechanical and finite element studies are needed to show long-term efficacy of this technique, however, early results indicate that such a construct is feasible. Furthermore, depending on the general medical condition of the patient, immediate postoperative weight bearing is possible and reasonable.

Adult↗
PubMed2006

Harvesting local cylinder autograft from adjacent vertebral body for anterior lumbar interbody fusion: surgical technique, operative feasibility and preliminary clinical results.

Autogenous iliac crest has long served as the gold standard for anterior lumbar arthrodesis although added morbidity results from the bone graft harvest. Therefore, femoral ring allograft, or cages, have been used to decrease the morbidity of iliac crest bone harvesting. More recently, an experimental study in the animal showed that harvesting local bone from the anterior vertebral body and replacing the void by a radio-opaque beta-tricalcium phosphate plug was a valid concept. However, such a concept precludes theoretically the use of posterior pedicle screw fixation. At one institution a consecutive series of 21 patients underwent single- or multiple-level circumferential lumbar fusion with anterior cages and posterior pedicle screws. All cages were filled with cancellous bone harvested from the adjacent vertebral body, and the vertebral body defect was filled with a beta-tricalcium phosphate plug. The indications for surgery were failed conservative treatment of a lumbar degenerative disc disease or spondylolisthesis. The purpose of this study, therefore, was to report on the surgical technique, operative feasibility, safety, benefits, and drawbacks of this technique with our primary clinical experience. An independent researcher reviewed all data that had been collected prospectively from the onset of the study. The average age of the patients was 39.9 (26-57) years. Bone grafts were successfully harvested from 28 vertebral bodies in all but one patient whose anterior procedure was aborted due to difficulty in freeing the left common iliac vein. This case was converted to a transforaminal interbody fusion (TLIF). There was no major vascular injury. Blood loss of the anterior procedure averaged 250 ml (50-350 ml). One tricalcium phosphate bone plug was broken during its insertion, and one endplate was broken because of wrong surgical technique, which did not affect the final outcome. One patient had a right lumbar plexopathy that was not related to this special technique. There was no retrograde ejaculation, infection or pseudoarthrosis. One patient experienced a deep venous thrombosis. At the last follow up (mean 28 months) all patients had a solid lumbar spine fusion. At the 6-month follow up, the pain as assessed on the visual analog scale (VAS) decreased from 6.9 to 4.5 (33% decrease), and the Oswestry disability index (ODI) reduced from 48.0 to 31.7 with a 34% reduction. However, at 2 years follow up there was a trend for increase in the ODI (35) and VAS (5). The data in this study suggest that harvesting a cylinder of autograft from the adjacent vertebral body is safe and efficient. Filling of the void defect with a beta-tricalcium phosphate plug does not preclude the use of posterior pedicle screw stabilization.

Adult↗
PubMed2006

Anterior reduction for cervical spine dislocation.

STUDY DESIGN: Retrospective analysis of a prospectively followed cohort. OBJECTIVE: Long-term evaluation of patients with anterior stabilization for dislocations of the cervical spine. SETTING: Level 1 trauma center. SUMMARY OF BACKGROUND DATA: Anterior stabilization of unstable cervical spine injuries is gaining popularity. However, the method of open reduction is controversial. METHODS: Forty-one consecutive patients with unstable dislocations/subluxations of the subaxial cervical spine were included. Closed reduction was attempted in all patients using Gardner-Wells traction. If this failed, an anterior open reduction was performed. Tricortical iliac crest autograft and anterior plating was used. Patients were assessed for: 1) rate of successful reduction and stabilization using only the anterior surgical approach; and 2) complications and long-term clinical and radiologic outcome. RESULTS: Two of eight (25%) anterior open reductions failed requiring posterior surgery. One of these patients had associated pedicle fractures with horizontal rotation of the lateral masses. All grafts had healed successfully at the most recent follow-up visit. Moderate neck discomfort was found in 5 of 41 patients. Significant neurologic improvement was observed. CONCLUSIONS: Most subluxations/dislocations of the subaxial cervical spine can be reduced using Gardner-Wells traction and successfully stabilized with anterior surgery alone. If closed reduction fails, anterior open reduction is successful in the majority of cases.

Adolescent↗
PubMed2006

Square-lashing technique in segmental spinal instrumentation: a biomechanical study.

Sublaminar wires have been used for many years for segmental spinal instrumentation in scoliosis surgery. More recently, stainless steel wires have been replaced by titanium cables. However, in rigid scoliotic curves, sublaminar wires or simple cables can either brake or pull out. The square-lashing technique was devised to avoid complications such as cable breakage or lamina cutout. The purpose of the study was therefore to test biomechanically the pull out and failure mode of simple sublaminar constructs versus the square-lashing technique. Individual vertebrae were subjected to pullout testing having one of two different constructs (single loop and square lashing) using either monofilament wire or multifilament cables. Four different methods of fixation were therefore tested: single wire construct, square-lashing wiring construct, single cable construct, and square-lashing cable construct. Ultimate failure load and failure mechanism were recorded. For the single wire the construct failed 12/16 times by wire breakage with an average ultimate failure load of 793 N. For the square-lashing wire the construct failed with pedicle fracture in 14/16, one bilateral lamina fracture, and one wire breakage. Ultimate failure load average was 1,239 N For the single cable the construct failed 12/16 times due to cable breakage (average force 1,162 N). 10/12 of these breakages were where the cable looped over the rod. For the square-lashing cable all of these constructs (16/16) failed by fracture of the pedicle with an average ultimate failure load of 1,388 N. The square-lashing construct had a higher pullout strength than the single loop and almost no cutting out from the lamina. The square-lashing technique with cables may therefore represent a new advance in segmental spinal instrumentation.

Absorptiometry, Photon↗
PubMed2006

Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee.

STUDY DESIGN: The Morbidity and Mortality database of the Scoliosis Research Society (SRS) was queried as to the incidence and type of complications as reported by its members for the treatment of adolescent idiopathic scoliosis (AIS) with spinal fusion and instrumentation procedures regarding surgical approach (anterior, posterior, or combined anterior-posterior) during a recent 3-year period. OBJECTIVE: To evaluate the incidence of surgeon-reported complications in a large series of spinal fusions with instrumentation for a single spinal deformity diagnosis and age group regarding surgical approach. SUMMARY OF BACKGROUND DATA: The SRS has been collecting morbidity and mortality data from its members since its formation in 1965 with the intent of using these data to assess the complications and adverse outcomes (death and/or spinal cord injury) of surgical treatment for spinal deformity. Surgical approaches to the management of treatment of AIS have a measurable impact on efficacy of correction, levels fused, and operative morbidity. However, there is a lack of consensus on the choice of surgical approach for the treatment of spinal deformity. METHODS: Of the 58,197 surgical cases submitted by members of the SRS in the years 2001, 2002, and 2003, 10.9% were identified as having had anterior, posterior, or combined spinal fusion with instrumentation for the diagnosis of AIS, and comprised the study cohort. All reported complications were tabulated and totaled for each of the 3 types of procedures, and statistical analysis was conducted. RESULTS: Complications were reported in 5.7% of the 6334 patients in this series. Of the 1164 patients who underwent anterior fusion and instrumentation, 5.2% had complications, of the 4369 who underwent posterior instrumentation and fusion, 5.1% had complications, and of the 801 who underwent combined instrumentation and fusion, 10.2% had complications. There were 2 patients (0.03%) who died of their complications. There was no statistical difference in overall complication rates between anterior and posterior procedures. However, the difference in complication rates between anterior or posterior procedures compared to combined procedures was highly significant (P < 0.0001). The differences in neurologic complication rates between combined and anterior procedures, as well as combined and posterior procedures were also highly statistically significant (P < 0.0001), but not between anterior and posterior procedures. CONCLUSIONS: This study shows that complication rates are similar for anterior versus posterior approaches to AIS deformity correction. Combined anterior and posterior instrumentation and fusion has double the complication rate of either anterior or posterior instrumentation and fusion alone. Combined anterior and posterior instrumentation and fusion also has a significantly higher rate of neurologic complications than anterior or posterior instrumentation and fusion alone.

Adolescent↗
PubMed2006

Expandable cage placement via a posterolateral approach in lumbar spine reconstructions. Technical note.

The authors describe a technique for inserting an expandable cage via a posterior extracavitary approach while protecting the segmental nerves. The advent of expandable cages has allowed the use of a less invasive anterior access to the spine, thereby decreasing the surgery-induced insult to the patient. In an attempt to minimize this trauma, the authors have used a posterolateral approach that has allowed them to perform neural decompression, anterior reconstruction with an expandable cage, and posterior stabilization with posterior pedicle screws. The authors describe their surgical technique of posterior circumferential decompression, which entails the use of an expandable cage that is inserted at 90 degrees, rotated in place where the corpectomy has been performed, and then expanded with special custom-made tools, thus respecting the segmental nerves of the lumbar spine. One case example is provided to illustrate the technique.

Aged↗
PubMed2005

Scheuermann's kyphosis: surgical management.

Indications for surgery in Scheuermann disease are not well codified and remain rare, as the natural history of the disease is in most cases benign. In the immature adolescent, conservative treatment, such as bracing or casting, can be tried for moderate curves. For larger curves, or in the adult, conservative treatment is usually not effective, and surgery can be considered. Such indications are mostly cosmetic for large curves above 75 degrees. Pain over the deformity or in the low back may represent another surgical indication, especially in the adult group. The question of anterior release or straight posterior fusion has become more of an actuality with the advent of powerful, third-generation stiff segmental instrumentation. However, the long-term results of a modern, posterior-only instrumentation fusion are not known. Concern about loss of correction, late pseudarthrosis or the need to remove instrumentation for infected hardware or due to late pain at the operative site must make us careful about choosing this method. Very rigid and large curves still require an anterior release, either done in a conventional or mini-open fashion, or through video-assisted thoracoscopic surgery. The extent of the posterior instrumentation has now been better defined. One must fuse the whole Cobb angle without hypercorrection and stop distally, above the first lordotic disc, to avoid sagittal decompensation. New approaches such as short anterior fusion with bone-on-bone techniques and pedicle substraction osteotomies have not yet been reported in the literature as having been used for treating Scheuermann's kyphosis. These should be considered experimental.

Adolescent↗
PubMed2005

The suprapedicle claw construct in anterior scoliosis surgery.

Proximal screw pullout is a well-recognized problem in anterior scoliosis surgery, with a rate of pseudarthrosis or screw pullout ranging from 15 to 30%. To prevent screw pullout at the top of the construct, the authors have devised the concept of a claw for the top instrumented vertebra. The claw consists of a classic anterior vertebral body screw inserted parallel to the inferior end-plate and in the posterior portion of the vertebral body 8 mm in front of the spine canal. After rib desarticulation, a laminar hook of a small size is inserted over the superior aspect of the pedicle of the same vertebra. The rod is then inserted into the two side openings of the screw and the hook. Compression across the hook and the screw is then performed, making a claw construct. This concept can also be extended in the case of early revision for a proximal screw pullout, where it is possible to revise the instrumentation with an offset connector linking the rod to the superior portion of the pedicle where the suprapedicule hook has been inserted. We report two cases where a suprapedicle claw was successfully used in anterior scoliosis correction of a right thoracic curve. Such a concept may represent the solution to proximal screw pullout in anterior scoliosis correction.

Adolescent↗
PubMed2005

Pull-out strength of the suprapedicle claw construct: a biomechanical study.

The pull-out of the superior screw is a well recognized problem in anterior instrumentation of the spine for scoliosis. A biomechanical pull-out study of anterior vertebral body screw in cadaveric thoracic spine was therefore designed to investigate and compare the pull-out strength of three different anterior vertebral body fixations using the AO Universal Spine System: simple bicortical screw, bicortical screw with an opposite washer (sometimes called pull-out resistant nut), and a new construct made of a bicortical screw with the addition of a suprapedicular hook on the same vertebra (or claw construct). The T4 to T9 vertebral bodies from six human cadavers (total of 36 specimens) were instrumented with three different instrumentation constructs after measuring the bone mineral density of each individual vertebra. After stabilization of the vertebral bodies, the screws were extracted employing a material testing system using axial pull-out. The maximum axial forces were recorded at the time of the construct failure. The mean ultimate fixation strength (UFS) values after being adjusted for bone mineral density and vertebral body diameter were 631, 711, and 1244 N for the three different constructs, respectively (screw alone, screw with an opposite washer, and screw with a suprapedicle claw). The difference in UFS was not significant for the first two constructs tested (screw alone and screw with an opposite washer). However, the difference in ultimate fixation strength between the claw and the other constructs was highly significant (P<0.0001). Specimens with low BMD did not benefit as much from claw construct as the ones did with a normal BMD. The failure mode of each construct was described, but was in neither case judged dangerous for the spinal cord. This study shows that the suprapedicle claw construct improves the pull-out strength of an anterior vertebral body screw by 80%, and changes the mode of failure so as not to rely only on the screw characteristics or solely on the vertebral body. By adding a suprapedicle hook in a claw configuration, one may prevent superior screw pull-out in anterior spine surgery for scoliosis.

Biomechanical Phenomena↗
PubMed2004

Is there a need for anterior release for 70-90 degrees masculine thoracic curves in adolescent scoliosis?

Large and stiff thoracic scoliotic curves in the adolescent represent a classic indication of anterior release followed by posterior instrumentation. However, third-generation segmental spinal instrumentations have shown increased correction of thoracic curves. Indication for an anterior release may therefore not be required even in large and stiff thoracic curves. The objective of the study was, therefore, to analyze retrospectively the results of third-generation segmental posterior instrumentation in large and stiff thoracic curves and to compare our results with the current literature of anterior release followed by posterior instrumentation. An independent observer, who had not participated in any of the case, reviewed our electronic database of adolescent scoliosis surgery (Scolisoft) with the following query: thoracic curves, Cobb angle between 70 degrees and 90 degrees and posterior surgery only. He was able to identify 19 patients whose thoracic curves were measured between 70 degrees and 90 degrees . Out of these, four had convex-side bending Cobb angle values of less than 45 degrees and were not included in the study, as they were judged too flexible. Fifteen patients (aged 11-18 years, mean 13.6 years) with thoracic scoliosis were left for the study (average Cobb angles 78.5 degrees with a flexibility index of 32.5% (range, 19-42%). The mean follow-up period was 32 months (range 18-64 months). Classic parameters of deformity correction were analysed. The average operative time was 314 min and the mean total blood loss was 1,875 ml. Average level of instrumented vertebrae was 12 (Range, 10-14). Postoperatively, the thoracic Cobb angle was measured at 34.8 degrees (range, 25-45 degrees ), which represents a correction rate of 54% (range, 40.0-67.1%) and remained unchanged at the last follow-up (35 degrees ). Patients with thoracic hypokyphosis improved from an average 11 degrees to 18 degrees . There were three complications (one excessive bleeding, one early infection and one late infection). One case showed an add-on phenomenon at the last follow-up. Coronal balance was improved from 1.8 cm (Range 0-4 cm) down to 0.75 cm (range 0-2.5 cm). Shoulder balance was improved from 1.3 cm (range 0-4 cm) down to 0.75 (0-2.5 cm). All patients reported satisfactory results except the patient with an adding-on phenomena. In the literature, most of the results of anterior thoracoscopic release and posterior surgery give a percentage of Cobb angle correction similar or inferior to our series for an average initial Cobb angle of less magnitude. Therefore, with adequate posterior release, and the use of third-generation segmental instrumentation there is no need for anterior release even for curves in the 70-90 degrees range.

Adolescent↗
PubMed2004

Kyphectomy in myelomeningocele with a modified Dunn-McCarthy technique followed by an anterior inlayed strut graft.

Rigid congenital kyphosis in myelomeningocele is associated with an important morbidity with skin breakdown, recurrent infection, and decreased function. Kyphectomy is the classic treatment to restore spinal alignment; however, surgery is associated with an important morbidity and long-term correction is uncertain. The authors retrospectively reviewed 9 patients with a mean age of 8.8 years who underwent a two stage surgical procedure: first a posterior kyphectomy with a modified Dunn-McCarthy fixation consisting of lumbar pedicle screws and long S-shape rods buttressing the anterior sacrum. Then a second stage done several weeks later consisting of a thoraco-abdominal approach to the spine with an inlay strut graft classically from T10-S1. The mean follow-up was 34 months (range 1-5 years). The kyphosis was corrected from a mean of 110 degrees of Cobb angle (range 70-130 degrees) to 15 degrees after surgery (45-0 degrees). There was no instrumentation failure, no loss of correction and no pseudarthrosis. Complications consisted of one intra-operative cardiac arrest fortunately reversible, a wound necrosis, one deep venous thrombosis and one late aseptic bursitis on the posterior hardware. Congenital kyphosis in myelomeningocele can be treated successfully with an initial posterior approach correction and instrumentation followed by an anterior approach allowing for anterior inlay impacted structural graft. The authors believe that this technique improves biomechanical and biological fusion mass anteriorly and will prevent late instrumentation failure and loss of correction.

Adolescent↗