Posterior Plate Research Articles

Percutaneous endoscopic transforaminal lumbar interbody fusion: is it worth it?

Interbody spine fusion with cages was first described by Bagby and has been performed for a long time now in a variety of different conditions. We developed a percutaneous endoscopic lumbar fusion technique based on the principles of Kambin and an original titanium cage. From 2004 to 2010, 57 patients were operated on, 17 patients were male with a mean age of 50.29 years (range 34-71 years) and 40 were female with a mean age of 57.42 years (29-90 years). Nineteen patients had a previous operation. Patients were operated on under local anaesthesia in the prone position under image intensifier and a transforaminal percutaneous endoscopic approach. Fifty cases had a bilateral cage through a bilateral endoscopic approach, and seven cases had a unilateral endoscopic approach only; of those, three cases had only one cage. Eleven patients had a contemporary posterior plate fixation at the same time of the endoscopic cage fusion. Eight patients had a postoperative radicular pain with paresthesias. Asymptomatic migration of the cages occurred in two cases and symptomatic migration requiring a conventional secondary reoperation in 13 cases after a mean delay of eight months (range three to 36 months). The mean ODI after two years or more was 34.3 % (initial ODI 69.4 %). The technique was introduced in our practice to take care of difficult or grave co-morbidity patients, and some patients had excellent lasting results following a very short procedure and hospital stay. However, given the 36 % complication rate in this series, we do not recommend it unless decisive technical improvements are made.

Biomechanical Study: Resistance Comparison of Posterior Antiglide Plate and Lateral Plate on Synthetic Bone Models Simulating Danis-Weber B Malleolar Fractures

ObjectiveThe purpose of this study was to compare different positions of plates in lateral malleolar Danis-Weber B fractures on synthetic bone: a lateral plate and a posterior antiglide plate. MethodsShort oblique fractures of distal fibula at the level of the syndesmosys were simulated with a fibular osteotomy in sixteen synthetic fibula bones (Synbone®). Eight fractures were fixed with lateral plating associated with an independent lag screw, and the other eight were fixed with posterior antiglide plating with a lag screw through the plate. A strain gage was installed at the center of each plate at the osteotomy site. Supination and external rotation forces were applied to each of the two groups at the bend. ResultsThe lateral position plate group suffered more deformity in response to supination forces compared to the group with the posterior antiglide plate, but this result was not statistically significant. In the tests with external rotation forces, the posterior antiglide plating group had significantly higher resistance (p<0.05). ConclusionWhen subjected to external rotation forces, osteosynthesis with posterior antiglide plate models simulating type B fractures of the lateral malleolus of the ankle is more resistant than that of the neutralization plate.

Comparação da resistência mecânica pela osteossíntese com placas fixadas nas posições lateral e posterior em fraturas Danis-Weber B.: estudo experimental

ObjectiveThe purpose of this study was to compare two different positions of the plate: lateral platting and posterior antiglide platting in lateral malleolar Danis-Weber B fractures on synthetic bone. MethodsShort oblique fractures of distal fibula at the level of the syndesmosys were simulated with a fibular osteotomy, in sixteen synthetic fibula bones (Synbone®). Eight fractures were fixed with lateral platting associated to an independent lag screw and the other eight were fixed with a posterior antiglide platting with a lag screw through the plate. A strain gage was installed at the center of each plate at the osteotomy site. Supination and external rotation forces were applied to each model of the two groups on the bend. ResultsThe lateral position plate group suffered more deformation in supination forces compared to the group with posterior antiglide plate, but without statistical significance. In the tests with external rotation forces, the posterior antiglide platting group showed statistically more resistance (p < 0.05). ConclusionThe osteosynthesis with posterior antiglide plate models simulating type B fractures of the lateral malleolus of the ankle is more resistant than the neutralization plate, when subjected to external rotation forces.

Zebrafish hoxd4a Acts Upstream of meis1.1 to Direct Vasculogenesis, Angiogenesis and Hematopoiesis

Mice lacking the 4th-group paralog Hoxd4 display malformations of the anterior vertebral column, but are viable and fertile. Here, we report that zebrafish embryos having decreased function of the orthologous hoxd4a gene manifest striking perturbations in vasculogenesis, angiogenesis and primitive and definitive hematopoiesis. These defects are preceded by reduced expression of the hemangioblast markers scl1, lmo2 and fli1 within the posterior lateral plate mesoderm (PLM) at 13 hours post fertilization (hpf). Epistasis analysis revealed that hoxd4a acts upstream of meis1.1 but downstream of cdx4 as early as the shield stage in ventral-most mesoderm fated to give rise to hemangioblasts, leading us to propose that loss of hoxd4a function disrupts hemangioblast specification. These findings place hoxd4a high in a genetic hierarchy directing hemangioblast formation downstream of cdx1/cdx4 and upstream of meis1.1. An additional consequence of impaired hoxd4a and meis1.1 expression is the deregulation of multiple Hox genes implicated in vasculogenesis and hematopoiesis which may further contribute to the defects described here. Our results add to evidence implicating key roles for Hox genes in their initial phase of expression early in gastrulation.

Development sites and early stages of eleven species of Clusiidae (Diptera) occurring in Europe.

Two hundred and ninety-six rearing records of 11 clusiid species (Diptera, Clusiidae) were obtained from 8 tree species in England, Finland, France, Norway, Russia and Scotland, mainly during the period 1994 to 2004. Larvae and puparia were found between annual layers of whitewood (sapwood and heartwood) of wet, decay-softened, dead wood. Levels of host tree specificity were low, most species were reared from 2-4 host trees, maximum 6. The clusiid larva is distinguished by: a small, translucent head skeleton with an obliquely-shaped apex to the artium; a pseudocephalon fixed in an inverted position except for an external, flattened section bearing the antennomaxillary organs; a spherical prothorax with a truncate rim embedded with sensilla and, a wedge-shaped anal segment bearing a pair of conspicuous, sclerotised, red-brown hooks on the inner margins of which are the posterior spiracular plates. Many of these features support a distinctive feeding mechanism, spot-sucking of biofilm coating wet, decaying whitewood. Early stage characters support the results of recent supraspecific taxonomic and systematic investigations, such as the synonymy of Paraclusia Czerny under Clusia Haliday and the recognition of species groups in Clusiodes Coquillett. Based on early stages, supraspecific clusiid taxa are easily recognised but at species level, differences are relatively fine-grained and minor. A key is provided to identify puparia of species reared in this study.

Reconstructive surgery for the post-hemiepiphysiodesis residual deformity in congenital scoliosis

Spinal hemiepiphysiodesis is a well-known surgical procedure for correcting angular deformity in which the anterior and/or posterior epiphyseal plates of several vertebrae are fused on the convex side of the curvature with the expectation of spontaneous correction through continued growth of the concave side. We report on a patient with congenital scoliosis that had problems after hemiepiphysiodesis and required a salvage, reconstructive, antero-posterior combined surgery with instrumentation and osteotomy. After hemiepiphysiodesis, a marked fusion mass and a loss of bony landmarks made osteotomy and correction with a salvage surgery extremely difficult. We suggest that confirming the fusion area after hemiepiphysiodesis and determining the appropriate osteotomy site by 3D reconstruction images are important before salvage operations.

The Posterolateral Approach for the Treatment of Trimalleolar Fractures

Anatomical reduction and fixation, early functional treatment, and prevention of posttraumatic osteoarthritis are the utmost goals in the treatment of articular fractures in the lower extremity. Especially in articular fractures of the ankle, where a high load transfer is omitted through a very small area, anatomical reduction is crucial. Historically, ankle fractures with involvement of large posterolateral fragments (Volkmann triangle) were reduced by an indirect technique. This procedure may be technically demanding and can be associated with important exposure to teratogenic irradiation. Additionally, impacted articular fragments cannot be reduced, and very large fragments tend to dislocate secondarily, thus leading to bad results. An easy, safe, and fast alternative to the indirect reduction technique is the fixation under direct visual control of the posterior tibial margin. Therefore, we advocate the posterolateral approach for the reduction Volkmann triangle in complex fractures of the ankle joint. It allows stable fixation of the posterior key fragment of the tibia with its syndesmosis. Impacted articular fragments can be reduced, and by the placement of a posterior buttress plate, secondary dislocation can be avoided. By the same incision, the placement of a posterior antiglide plate to the fibula is possible, and through a simple maneuver, the approach to the medial malleolus is granted.

Zic3 is required in the extra-cardiac perinodal region of the lateral plate mesoderm for left–right patterning and heart development

Mutations in ZIC3 cause human X-linked heterotaxy and isolated cardiovascular malformations. A mouse model with targeted deletion of Zic3 demonstrates an early role for Zic3 in gastrulation, CNS, cardiac and left-right axial development. The observation of multiple malformations in Zic3(null) mice and the relatively broad expression pattern of Zic3 suggest its important roles in multiple developmental processes. Here, we report that Zic3 is primarily required in epiblast derivatives to affect left-right patterning and its expression in epiblast is necessary for proper transcriptional control of embryonic cardiac development. However, cardiac malformations in Zic3 deficiency occur not because Zic3 is intrinsically required in the heart but rather because it functions early in the establishment of left-right body axis. In addition, we provide evidence supporting a role for Zic3 specifically in the perinodal region of the posterior lateral plate mesoderm for the establishment of laterality. These data delineate the spatial requirement of Zic3 during left-right patterning in the mammalian embryo, and provide basis for further understanding the molecular mechanisms underlying the complex interaction of Zic3 with signaling pathways involved in the early establishment of laterality.

Posterior Muscolofascial Reconstruction Incorporated into Urethrovescical Anastomosis During Robot-Assisted Radical Prostatectomy

The rationale of posterior musculofascial plate reconstruction during radical prostatectomy is to shorten the time to reach urinary continence recovery and to reduce the risk of bleeding and anastomosis leakage. We describe our original technique incorporating the posterior muscolofascial reconstruction into urethrovesical anastomosis using robot-assisted radical prostatectomy (RARP). For this reconstructive step, we use a 30-cm V-Loc 90 3-0 barbed suture (V-20 tapered needle). Specifically, the free edge of the posterior layer of the Denonvilliers fascia is approximated to the posterior part of the sphincteric apparatus in a running fashion from left to right. The musculature of the urethral wall is incorporated in this first layer of the running suture. This suture is then continued back to the left in a second layer incorporating the anterior layer of the Denonvilliers fascia (or prostatovesical muscle), the bladder neck, and again the urethra, this time also with urethral mucosa. The urethrovesical anastomosis is completed using a second running barbed suture (15-cm V-Loc 90 3-0 barbed suture, V-20 tapered needle). No intraoperative complications were observed during this step of the procedure. Anastomotic leakages were observed only in 2% of cases. Only 12.5% showed urinary incontinence after catheter removal (1-2 pads). At mean follow-up of 9 months, the urinary continence recovery was 95%, and an anastomosis stricture necessitating an endoscopic incision developed in only three (1.5%) patients. Recent systematic reviews of the literature showed only a minimal advantage in favor of posterior musculofascial reconstruction in terms of urinary continence recovery within 1 month after radical prostatectomy. We support the use of this step of RARP because it is simple, reproducible, with a very limited increase in operative time, and with only a slight risk of potential harm to the patient. Moreover, it could improve hemostasis and provide greater support for a delicate anastomosis.

Acetabular Distraction: An Alternative for Severe Defects with Chronic Pelvic Discontinuity?

Stabilization of a pelvic discontinuity with a posterior column plate with or without an associated acetabular cage sometimes results in persistent micromotion across the discontinuity with late fatigue failure and component loosening. Acetabular distraction offers an alternative technique for reconstruction in cases of severe bone loss with an associated pelvic discontinuity. We describe the acetabular distraction technique with porous tantalum components and evaluate its survival, function, and complication rate in patients undergoing revision for chronic pelvic discontinuity. Between 2002 and 2006, we treated 28 patients with a chronic pelvic discontinuity with acetabular reconstruction using acetabular distraction. A porous tantalum elliptical acetabular component was used alone or with an associated modular porous tantalum augment in all patients. Three patients died and five were lost to followup before 2 years. The remaining 20 patients were followed semiannually for a minimum of 2 years (average, 4.5 years; range, 2-7 years) with clinical (Merle d'Aubigné-Postel score) and radiographic (loosening, migration, failure) evaluation. One of the 20 patients required rerevision for aseptic loosening. Fifteen patients remained radiographically stable at last followup. Four patients had early migration of their acetabular component but thereafter remained clinically asymptomatic and radiographically stable. At latest followup, the average improvement in the patients not requiring rerevision using the modified Merle d'Aubigné-Postel score was 6.6 (range, 3.3-9.6). There were no postoperative dislocations; however, one patient had an infection, one a vascular injury, and one a bowel injury. Acetabular distraction with porous tantalum components provides predictable pain relief and durability at 2- to 7-year followup when reconstructing severe acetabular defects with an associated pelvic discontinuity. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Transcriptional regulatory networks in epiblast cells and during anterior neural plate development as modeled in epiblast stem cells

Somatic development initiates from the epiblast in post-implantation mammalian embryos. Recent establishment of epiblast stem cell (EpiSC) lines has opened up new avenues of investigation of the mechanisms that regulate the epiblast state and initiate lineage-specific somatic development. Here, we investigated the role of cell-intrinsic core transcriptional regulation in the epiblast and during derivation of the anterior neural plate (ANP) using a mouse EpiSC model. Cells that developed from EpiSCs in one day in the absence of extrinsic signals were found to represent the ANP of ~E7.5 embryos. We focused on transcription factors that are uniformly expressed in the E6.5 epiblast but in a localized fashion within or external to the ANP at E7.5, as these are likely to regulate the epiblast state and ANP development depending on their balance. Analyses of the effects of knockdown and overexpression of these factors in EpiSCs on the levels of downstream transcription factors identified the following regulatory functions: cross-regulation among Zic, Otx2, Sox2 and Pou factors stabilizes the epiblastic state; Zic, Otx2 and Pou factors in combination repress mesodermal development; Zic and Sox2 factors repress endodermal development; and Otx2 represses posterior neural plate development. All of these factors variably activate genes responsible for neural plate development. The direct interaction of these factors with enhancers of Otx2, Hesx1 and Sox2 genes was demonstrated. Thus, a combination of regulatory processes that suppresses non-ANP lineages and promotes neural plate development determines the ANP.

Cubitus varus in adults correction with lateral closing wedge osteotomy and fixation with posterior plating

To share the result of lateral closing wedge osteotomy and fixation with posterior reconstruction plate in correction of cubitus varus in adults. It is a retrospective case analysis of 8 cases of cubitus varus in adult treated with lateral closing wedge osteotomy through posterior triceps retracting approach. Internal fixation was done with two posterior reconstruction plates. All cases were from 15 to 29 years of age (mean 22.3 ) with 3 female and 5 male. All had cubitus varus ranging from 15- 28 deg (mean 20.16 deg) due to childhood malunited supracondylar fracture of humerus. Indication for operation was cosmetic reason only. Follow up duration was 4-22 months (mean 12.5 months). All the osteotomy united clinically in mean duration of 9 weeks ( range 8-12 weeks) with mean carrying angle 8.33 degree in postoperative phase. There was no loss of motion, no loss of fixation, no surgical site infection, nonunion or neurovascular deficit. Lateral closing wedge corrective osteotomy and fixation with posterior reconstruction plate is easy technique with satisfactory result in correction of cubitus varus in adults. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-2, 49-53 DOI: http://dx.doi.org/10.3126/jcmsn.v8i2.6839

Crater-and-split technique for phacoemulsification: Modification of the crater-and-chop technique

We describe a modification of the crater-and-chop technique for removing cataracts of all densities. Following creation of a central crater approximately 3.0 mm in diameter at the geometric center of the endonucleus, a nucleus splitter is inserted under the capsule and the phaco tip is inserted in the crater. Simultaneously, the splitter is moved from the nucleus periphery toward the phaco tip horizontally to split the nucleus and both the phaco tip and nucleus splitter are pushed aside as they come very close without vacuum at any point. The nucleus is rotated and splitting is repeated in the same manner until the nucleus is divided into pieces that are small enough to be emulsified easily. With this technique, the soft nucleus is split without vacuum and a very hard nucleus can be split through the posterior plate with minimal stress to zonular fibers.

Acoustic characteristics of the advertisement call of Trachycephalus atlasBokermann, 1966 (Anura: Hylidae)

Only three of the 12 recognized species of Trachycephalus Tschudi (Frost 2011) present an occipital crest— Trachycephalus atlas Bokermann, T. nigromaculatus Tschudi, and T. jordani (Stejneger and Test). The latter species is found in Colombia, Ecuador, and Peru. Trachycephalus nigromaculatus is found in the Brazilian Atlantic Forest of São Paulo, Rio de Janeiro, Espirito Santo, Minas Gerais, and southern Bahia states, while T. atlas is restricted primarily to the Caatinga of the Brazilian Northeast (Frost 2011), but overlaps with T. nigromaculatus in the Atlantic Forest of southern Bahia. The two species can be differentiated by the more pronounced posterior cephalic plate, wider inter-orbital distance, and lower and wider head in T. atlas (Bokermann 1966). Herein we describe the acoustic characteristics of advertisement call of T. atlas and compared with other Trachycephalus species.

Caudal genes in blood development and leukemia

Members of the caudal gene family (in mice and humans: Cdx1, Cdx2, and Cdx4) have been studied during early development as regulators of axial elongation and anteroposterior patterning. In the adult, Cdx1 and Cdx2, but not Cdx4, have been intensively explored for their function in intestinal tissue homeostasis and the pathogenesis of gastrointestinal cancers. Involvement in embryonic hematopoiesis was first demonstrated in zebrafish, where cdx genes render posterior lateral plate mesoderm competent to respond to genes specifying hematopoietic fate, and compound mutations in cdx genes thus result in a bloodless phenotype. Parallel studies performed in zebrafish embryos and murine embryonic stem cells (ESCs) delineate conserved pathways between fish and mammals, corroborating a BMP/Wnt-Cdx-Hox axis during blood development that can be employed to augment derivation of blood progenitors from pluripotent stem cells in vitro. The molecular regulation of Cdx genes appears complex, as more recent data suggest involvement of non-Hox-related mechanisms and the existence of auto- and cross-regulatory loops governed by morphogens. Here, we will review the role of Cdx genes during hematopoietic development by comparing effects in zebrafish and mice and discuss their participation in malignant blood diseases.

The preclinical sheep model of high tibial osteotomy relating basic science to the clinics: standards, techniques and pitfalls

To develop a preclinical large animal model of high tibial osteotomy to study the effect of axial alignment on the lower extremity on specific issues of the knee joint, such as in articular cartilage repair, development of osteoarthritis and meniscal lesions. Preoperative planning, surgical procedure and postoperative care known from humans were adapted to develop a HTO model in the adult sheep. Thirty-five healthy, skeletally mature, female Merino sheep between 2 and 4 years of age underwent a HTO of their right tibia in a medial open-wedge technique inducing a normal (group 1) and an excessive valgus alignment (group 2) and a closed-wedge technique (group 3) inducing a varus alignment with the aim of elucidating the effect of limb alignment on cartilage repair in vivo. Animals were followed up for 6 months. Solid bone healing and maintenance of correction are most likely if the following surgical principles are respected: (1) medial and longitudinal approach to the proximal tibia; (2) biplanar osteotomy to increase initial rotatory stability regardless of the direction of correction; (3) small, narrow but long implant with locking screws; (4) posterior plate placement to avoid slope changes; (5) use of bicortical screws to account for the brittle bone of the tibial head and to avoid tibial head displacement. Although successful high tibial osteotomy in sheep is complex, the sheep may--because of its similarities with humans--serve as an elegant model to induce axial malalignment in a clinically relevant environment, and osteotomy healing under challenging mechanical conditions.

“Snodgraft” Technique for the Treatment of Primary Distal Hypospadias: Pushing the Envelope

"Snodgraft" modification has been proposed to reduce the risk of meatal/neourethral stenosis in distal hypospadias. We applied the Snodgraft technique by using inner preputial graft in primary distal hypospadias repair. A total of 102 consecutive patients undergoing the Snodgraft procedure were prospectively studied between 2006 and 2011. Mean patient age was 7.2 years. Localization of the meatus was glanular in 5 patients, coronal in 49, subcoronal in 45 and mid penile in 3. In all patients the posterior urethral plate was incised, and the graft harvested from the inner prepuce was sutured from the old meatus to the tip of the glans. A neourethra was created over a urethral catheter using 6-zero polyglactin suture. An interpositional flap was laid over the urethra as a second barrier. All patients were followed at 3 to 6-month intervals for cosmetic and functional results. At a mean of 2.4 years of followup no patient had meatal stenosis or diverticulum at the inlay graft site. However, urethrocutaneous fistula was observed in 10 patients (9.8%). A slit-like appearance of neomeatus was achieved in all patients. During followup no obstructive urinary flow pattern was detected, and early and long-term maximum urine flow rates were comparable. No meatal/neourethral stenosis was observed in any patient undergoing a Snodgraft procedure. A randomized trial will be needed to prove that the incidence of meatal/neourethral stenosis is lower after Snodgraft repair compared to routine tubularized incised plate repair.

Long-Term Outcomes of Lumbar Posterior Apophyseal End-Plate Lesions in Children and Adolescents

A lesion of the lumbar posterior apophyseal end plate in children and adolescents causes symptoms similar to those associated with a herniated disc. However, the end-plate lesion and the herniated disc differ in terms of pathology. The purpose of this study was to clarify the long-term clinical and radiographic outcomes in children and adolescents who were treated either surgically or conservatively for a lumbar posterior apophyseal end-plate lesion. We identified twenty-four consecutive patients who had been treated in the sports clinic of our hospital. The mean age at the first medical examination was 14.5 years. The mean follow-up time was 13.8 years. The mean age at the time of final follow-up was 28.4 years. All twenty-four patients had symptomatic low back pain with sciatica. All but two were active in sports. Sixteen patients were treated conservatively, and eight patients underwent surgical intervention. Skeletal maturity was evaluated on the basis of the appearance of the secondary ossification center of L3. The apophyseal stage ("A" stage), which was assigned when the secondary ossification center of the vertebral body was visible on radiographs, was seen most frequently. Both the surgically treated group and the conservatively treated group demonstrated progressive disc degeneration at the involved level. The average Roland-Morris Disability Questionnaire (RDQ) score was 1.3 for the patients treated conservatively and 1.8 for those treated surgically, a nonsignificant difference. One patient developed spinal stenosis after twelve years of conservative treatment. One patient treated surgically demonstrated severe lumbar instability. There were no significant associations between the magnetic resonance imaging (MRI) findings and RDQ scores. Histological examination of surgical specimens showed irregular alignment of the anulus fibrosus, with degenerative matrix and chondrocytes without a nucleus. The long-term outcome for patients with a posterior end-plate lesion is favorable, regardless of whether it is treated surgically or nonsurgically.

Description of Sinaxonopsis unicucrus sp. nov. et gen. nov. (Acari: Hydrachnidia: Aturidae) from Anhui Province, China

A new genus Sinaxonopsis gen. nov. with a new species Sinaxonopsis unicucrus sp. nov. from China is described. Adults of the new genus are autapomorphic among Aturidae in having a large posterior dorsal plate and a pair of anterior plates, numerous cetabula scattered on their surfaces from both sides of the gonopore to posterolateral area, CxIV extending far laterally with a ridge, the third and fourth legs of male exhibiting sexual dimorphism with various modified setae, claws of male III-L-6 heteromorphic and modified, male IV-L-6 with thicker distal ends, and a pair of well-developed dorsal projections. The systematic status of the new genus is discussed. The new genus is tentatively assigned to Axonopsinae but it certainly is not closely related to any previously described genus.

Biomechanical Analysis of Acetabular Revision Constructs: Is Pelvic Discontinuity Best Treated With Bicolumnar or Traditional Unicolumnar Fixation?

Pelvic discontinuity in revision total hip arthroplasty presents problems with component fixation and union. A construct was proposed based on bicolumnar fixation for transverse acetabular fractures. Each of 3 reconstructions was performed on 6 composite hemipelvises: (1) a cup-cage construct, (2) a posterior column plate construct, and (3) a bicolumnar construct (no. 2 plus an antegrade 4.5-mm anterior column screw). Bone-cup interface motions were measured, whereas cyclical loads were applied in both walking and descending stair simulations. The bicolumnar construct provided the most stable construct. Descending stair mode yielded more significant differences between constructs. The bicolumnar construct provided improved component stability. Placing an antegrade anterior column screw through a posterior approach is a novel method of providing anterior column support in this setting.