In major joint diseases the human synovium retains its potential to form repair cartilage.

The inner surface layer of human joints, the synovium, is a source of stem cells for the repair of articular cartilage defects. We investigated the potential of the normal human synovium to form novel cartilage and compared its chondrogenic capacity with that of two patient groups suffering from major joint diseases: young adults with femoro-acetabular impingement syndromes of the hip (FAI), and elderly individuals with osteoarthritic degeneration of the knee (OA). Synovial membrane explants of these three patient groups were induced in vitro to undergo chondrogenesis by growth factors: bone morphogenetic protein-2 (BMP-2) alone, transforming growth factor-ß1 (TGF-ß1) alone, or a combination of these two. Quantitative evaluations of the newly formed cartilages were performed respecting their gene activities, as well as the histochemical, immunhistochemical, morphological and histomorphometrical characteristics. Formation of adult articular-like cartilage was induced by the BMP-2/TGF-ß1 combination within all three groups, and was confirmed by adequate gene-expression levels of the anabolic chondrogenic markers; the levels of the catabolic markers remained low. Our data reveal that the chondrogenic potential of the normal human synovium remains uncompromised, both in FAI and OA. The potential of synovium-based clinical repair of joint cartilage may thus not be impaired by age-related joint pathologies.

Exposure of the Lumbosacral Plexus by Using the Pararectus Approach: A Technical Note.

BACKGROUND: Surgical exploration of the lumbosacral plexus is challenging. Previously described approaches reach from invasive open techniques with osteotomy of the ilium to laparoscopic techniques. OBJECTIVE: To describe a novel surgical technique to explore lumbosacral plexopathies such as benign nerve tumors or iatrogenic lesions of the lumbosacral plexus in 4 case examples. METHODS: We retrospectively evaluated 4 patients suffering from pathologies or injuries of the lumbosacral plexus between 2017 and 2019. The mean follow-up period after surgery was 23.5 (range 11-52) months. All patients underwent neurolysis of the lumbosacral plexus using the single incision, intrapelvic, extraperitoneal pararectus approach. RESULTS: In all patients, the pathology of the lumbosacral plexus was successfully visualized, proving feasibility of the extraperitoneal pararectus approach for this indication. There were no major complications, and all patients recovered well. CONCLUSION: The pararectus approach allows excellent visualization of the lumbar plexus and intrapelvic lesions of the femoral and sciatic nerves.

Revision of a Failed Primary Total Hip Arthroplasty following Excessive Reaming with a Medial Cup Protrusion.

Background and Objectives: Atraumatic intrapelvic protrusion of the acetabular component following excessive reaming of the acetabulum with a far medial positioning of the cup is a rare, but serious complication of a total hip arthroplasty (THA). This study analyzes the factors contributing to this uncommon complication and presents the outcome after the revision surgery using the Ganz reinforcement ring combined with a bone graft and plating of the posterior column and/or screws for the anterior column. Materials and Methods: A retrospective case series study with seven patients (four males, mean age 76 ± 10 years (60−86)) that underwent a revision THA within 24 ± 17 days (5−60) after an atraumatic periprosthetic acetabular fracture with a medial cup protrusion was performed. All fractures were reconstructed with a Ganz reinforcement ring and bone graft with a mean follow-up of 1.7 ± 1.7 years (0.5−5). Radiographs were evaluated for the following: (i) cup positioning immediately after the primary THA and the revision surgery, (ii) cup migration in the follow-up, and (iii) fracture healing. Results: The position of the acetabular component as assessed on the postoperative radiographs after the index surgery and before the complete medial cup protrusion showed a cup placement beyond the ilioischial line indicative of a fracture of the medial wall. The revision surgery with the reconstruction of the medial wall with a Ganz reinforcement ring combined with a bone graft restored in the presented cases the center of rotation in the horizontal direction with a statistical significance (p < 0.05). During the follow-up, there was no aseptic loosening with the relevant cup migration or significant change in the position of the acetabular cup at the final follow-up (p > 0.05) after the revision. All seven fractures and bone grafts realized a bone union until the latest follow-up. Conclusions: Following excessive reaming, the acetabular component was placed too far medially and resulted in an intrapelvic cup protrusion. An unstable cup following a fracture of the medial wall was evident on the immediate postoperative radiographs. In the case of the medial wall perforation with an intrapelvic cup protrusion after the primary THA, the reconstruction with a Ganz reinforcement ring was a successful treatment option resulting in the fracture healing and a stable cup positioning. Surgeons should be aware of that rare and probably underreported complication and restore the anatomic center of rotation by treating the defect intraoperatively.

The Synovium of Human Osteoarthritic Joints Retains Its Chondrogenic Potential Irrespective of Age.

The autologous synovium is a potential tissue source for local induction of chondrogenesis by tissue engineering approaches to repair articular cartilage defects that occur in osteoarthritis. It was the aim of the present study to ascertain whether the aging of human osteoarthritic patients compromises the chondrogenic potential of their knee-joint synovium and the structural and metabolic stability of the transformed tissue. The patients were allocated to one of the following two age categories: 54-65 years and 66-86 years (n = 7-11 donors per time point and experimental group; total number of donors: 64). Synovial biopsies were induced in vitro to undergo chondrogenesis by exposure to bone morphogenetic protein-2 (BMP-2) alone, transforming growth factor-ß1 (TGF-ß1) alone, or a combination of the two growth factors, for up to 6 weeks. The differentiated explants were evaluated morphologically and morphometrically for the volume fraction of metachromasia (sulfated proteoglycans), immunohistochemically for type-II collagen, and for the gene expression levels of anabolic chondrogenic markers as well as catabolic factors by a real-time polymerase chain reaction analysis. Quantitative metachromasia revealed that chondrogenic differentiation of human synovial explants was induced to the greatest degree by either BMP-2 alone or the BMP-2/TGF-ß1 combination, that is, to a comparable level with each of the two stimulation protocols and within both age categories. The BMP-2/TGF-ß1combination protocol resulted in chondrocytes of a physiological size for normal human articular cartilage, unlike the BMP-2-alone stimulation that resulted in cell sizes of terminal hypertrophy. The stable gene expression levels of the anabolic chondrogenic markers confirmed the superiority of these two stimulation protocols and demonstrated the hyaline-like qualities of the generated cartilage matrix. The gene expression levels of the catabolic markers remained extremely low. The data also confirmed the usefulness of experimental in vitro studies with bovine synovial tissue as a paradigm for human synovial investigations. Our data reveal the chondrogenic potential of the human knee-joint synovium of osteoarthritic patients to be uncompromised by aging and catabolic processes. The potential of synovium-based clinical engineering (repair) of cartilage tissue using autologous synovium may thus not be reduced by the age of the human patient. Impact statement Our data reveal that in younger and older age groups alike, synovial explants from osteoarthritic joints can be equally well induced to undergo chondrogenesis in vitro; that is, the chondrogenic potential of the human synovium is not compromised by aging. These findings imply that the autologous synovium represents an adequate tissue source for the repair of articular cartilage in clinical practice by tissue engineering approaches in human patients suffering from osteoarthritis, independent of the patient's age.

Anterior-posterior view by full-body digital X-ray to rule out severe spinal injuries in Polytraumatized patients.

BACKGROUND: Spinal injuries are present in 16-31% of polytraumatized patients. Rapid identification of spinal injuries requiring immobilization or operative treatment is essential. The Lodox-Statscan (LS) has evolved into a promising time-saving diagnostic tool to diagnose life-threatening injuries with an anterior-posterior (AP)-full-body digital X-ray. METHODS: We aimed to analyze the diagnostic accuracy and the interrater reliability of AP-LS to detect spinal injuries in polytraumatized patients. Therefore, within 3 years, AP-LS of polytraumatized patients (ISS ≥ 16) were retrospectively analyzed by three independent observers. The sensitivity and specificity of correct diagnosis with AP-LS compared to CT scan were calculated. The diagnostic accuracy was evaluated by using the area under the ROC (receiver operating characteristic curve) for sensitivity and specificity. Interrater reliability between the three observers was calculated using Fleiss' Kappa. The sensitivity of AP-LS was further analyzed by the severity of spinal injuries. RESULTS: The study group included 320 patients (48.5 years ±19.5, 89 women). On CT scan, 207 patients presented with a spinal injury (65%, total of 332 injuries). AP-LS had a low sensitivity of 9% (31 of 332, range 0-24%) and high specificity of 99% (range 98-100%). The sensitivity was highest for thoracic spinal injuries (14%). The interrater reliability was slight (κ = 0.02; 95% CI: 0.00, 0.03). Potentially unstable spinal injuries were more likely to be detected than stable injuries (sensitivity 18 and 6%, respectively). CONCLUSION: This study demonstrated high specificity with low sensitivity of AP-LS in detecting spinal injuries compared to CT scan. In polytraumatized patients, AP-LS, implemented in the Advanced Trauma Life Support-algorithm, is a helpful tool to diagnose life-threatening injuries. However, if spinal injuries are suspected, performing a full-body CT scan is necessary for correct diagnosis.

Transfer of osteochondral shell autografts to salvage femoral head impaction injuries in hip trauma patients.

INTRODUCTION: Femoral head impaction defects are observed with variable severity, as a result of traumatic hip dislocations which can be caused by traffic accidents or seen in professional athletes amongst other mechanisms. Compression of the articular cartilage and the subchondral bone into the femoral head results in irregular articular surfaces influencing the outcome with predisposition to osteoarthritis, and being predictive for the need for delayed total hip replacement. This study reports the outcome after a minimum follow-up (FU) of five years in a consecutive series treated with transfer of osteochondral shell autografts in hips (TOSAH) from the head-neck junction into the defect using surgical hip dislocation. PATIENTS AND METHODS: Between 06/2007 and 03/2014 a series of twelve consecutive patients (mean age: 35yrs, range 18-53; median Injury Severity Score: 12, range 9-27) sustained a traumatic posterior hip dislocation in combination with acetabular and/or Pipkin fractures and were inter alia treated using TOSAH using surgical hip dislocation. Conversion to total hip replacement (THR) during FU was noted as failure. Patients were clinically (Merle d'Aubigné score) and radiographically assessed for occurrence of osteoarthritis (OA), avascular necrosis (AVN) and/or heterotopic ossification (HO) at a minimal follow-up of five years. RESULTS: Mean follow-up was 6.9 years (5.0-11.6). At five-year follow-up, we found a survivorship of 57.1% (95% Confidence interval {CI}, 46.7-100%). Four patients required conversion to a total hip replacement at 11, 16, 28 and 44 months respectively after the TOSAH procedure due to osteoarthritis progression. One patient required conversion to a total hip replacement 12 months after TOSAH procedure due to AVN. One patient was lost to follow-up after 2.7 years. The remaining six patients with preserved hips presented with a median Merle-d'Aubigné score of 16 points (range: 14-18) and no AVN. Two patients showed asymptomatic grade I osteoarthritis according to Tönnis at latest follow-up and three patients showed mild asymptomatic HO according to Brooker (Grade I-II). CONCLUSION: The presented technique can be used as a salvage procedure for severely injured hip joints and to preserve the hip joint at midterm with satisfying clinical and radiological outcomes.

Direct anterior decompression of L4 and L5 nerve root in sacral fractures using the pararectus approach: a technical note.

PURPOSE: To describe a new surgical technique for neurolysis and decompression of L4 and L5 nerve root entrapment after vertical sacral fractures via the pararectus approach for acetabular fractures, and to present four case examples. PATIENTS AND METHODS: We retrospectively evaluated four patients suffering radiculopathy from entrapment of the L4 or L5 nerve root in vertical sacral fractures between January and December 2016. The mean follow-up period after surgery was 18 (range 7-27) months. All patients underwent direct decompression and neurolysis of the L4 and L5 nerve roots via the single-incision, intrapelvic, extraperitoneal pararectus approach. RESULTS: In all patients, the L4 and L5 nerve root was successfully visualized and decompressed, proving feasibility of the pararectus approach for this indication. No patient presented with a neural tear. Complete neurologic recovery was present in one patient at last follow-up; two patients had incomplete recovery of their radiculopathy; and one patient had no improvement after nerve root decompression. CONCLUSIONS: The pararectus approach allows for sufficient visualisation and direct decompression and neurolysis of the L4 and L5 nerve root entrapped in vertical sacral fractures. Although neurologic recovery was not achieved in all patients in this small case series, the approach may be a suitable alternative to posterior approaches and other anterior approaches such as the lateral window of the ilioinguinal approach.

Surgical Hip Dislocation for Exposure of the Posterior Column.

BACKGROUND: Surgical hip dislocation is performed for safe and efficient management of acetabular fractures predominantly involving the posterior column. The dislocation of the femoral head allows for direct visualization of the hip joint during fracture treatment. DESCRIPTION: The patient is placed in the lateral decubitus position with sterile preparation and draping of the ipsilateral leg to allow for dislocation. The skin incision is straight and centered over the greater trochanter. After the skin incision, the interval between the gluteus maximus and medius muscles is developed. The sciatic nerve is identified, and special attention to the course of the medial circumflex femoral artery is given during dissection of the piriformis and triceps coxae muscles (obturator internus and superior and inferior gemelli muscles). The latter are incised 2 cm posterior to their insertion on the posterior aspect of the greater trochanter. The vastus lateralis muscle belly is elevated from the lateral femoral shaft, and a trochanteric osteotomy is performed. The trochanteric medallion is rotated 90°, and the gluteus minimus muscle is released from the capsule. After complete exposure of the hip capsule, a z-shaped capsulotomy is performed whereby any injury to the posterior capsular attachments of a posterior wall fragment is avoided. The posterior column and the greater and lesser sciatic notches are exposed, with the sciatic nerve under protection. The femoral head is dislocated either anteriorly or posteriorly to obtain direct visualization of the hip. Reduction begins at the articular surface, in cases of marginal impaction, and proceeds to the posterior wall and/or posterior column and the anterior column, when involved. For fixation, 3.5-mm cortical screws acting as positioning or lag screws and reconstruction plates are used. The capsule is sutured, the trochanteric fragment is reduced anatomically and stabilized with two 3.5-mm cortical screws, the piriformis and triceps coxae muscles are sutured, and a layered closure is performed. ALTERNATIVES: The Kocher-Langenbeck approach might be used instead. RATIONALE: Surgical hip dislocation facilitates assessment of cartilage damage at the acetabulum, marginal impaction, labral tears and femoral head lesions, removal or reinsertion of free intra-articular fracture fragments, direct visualization of the accuracy of reduction, and verification of extra-articular screw placement.

Open Reduction and Internal Fixation of Acetabular Fractures Using the Modified Stoppa Approach.

BACKGROUND: The modified Stoppa approach is performed for safe and efficient management of acetabular fractures involving the anterior column. This approach avoids dissection of the inguinal canal, the femoral nerve, and the external iliac vessels as seen in the "second window" of the ilioinguinal approach and has thus been shown to be less invasive than the ilioinguinal approach1. As an intrapelvic approach, it facilitates the management of medial displacement fracture patterns involving the quadrilateral plate and dome impaction that typically occur in the elderly2,3. The reduced morbidity of this approach is of particular relevance for elderly patients who must respond to the stresses of injury and surgery with diminished physiological reserves. DESCRIPTION: The specific surgical steps include preoperative planning, patient positioning and setup, a Pfannenstiel incision, superficial and deep dissection, development of the Retzius space and retraction of the bladder, exposure of the superior pubic ramus and iliopectineal eminence, dissection and ligation of a potential corona mortis, exposure of the obturator nerve and vessels, subperiosteal preparation of the pubic ramus with retraction of the external iliac vessels, subperiosteal exposure of the quadrilateral plate with detachment of the internal obturator muscle and exposure of the posterior column, assessment of residual displacement by fluoroscopic views, longitudinal soft-tissue or lateral skeletal traction (optional) for reduction of medial displacement of the femoral head, disimpaction of the acetabular dome fragment and grafting of the supra-acetabular void (optional) under fluoroscopic and arthroscopic (optional) control, and reduction and fixation of extra-articular components (iliac wing posteriorly and pubic ramus anteriorly), the posterior column (infra-acetabular screw), and the quadrilateral plate (buttress plate). Before wound closure, the urine output is checked for occurrence of hematuria, an indication of bladder penetration. The anterior lamina of the rectus sheath is then sutured, and a layered closure performed. ALTERNATIVES: The ilioinguinal approach might be used instead. RATIONALE: The modified Stoppa approach avoids dissection within the inguinal canal, the second window of the ilioinguinal approach. Therefore, this approach is less invasive and might be an alternative for joint-preserving surgery, especially in the elderly.

The Pararectus Approach: A New Concept.

BACKGROUND: Even 50 years after the introduction of the extrapelvic ilioinguinal approach for open reduction and internal fixation of acetabular fractures involving predominantly the anterior column, this approach is still acknowledged as being the so-called gold standard1. The pattern of acetabular fractures has changed within the last 10 to 20 years2,3, with a greater prevalence of quadrilateral plate fractures that is due in part to the increase in elderly trauma. The intrapelvic approach, also called the modified Stoppa approach4-6, was introduced as a less invasive alternative to the extrapelvic ilioinguinal approach, mostly combined with the first window of the ilioinguinal approach. The Pararectus approach also offers intrapelvic surgical access and has demonstrated safe surgical dissection with enhanced exposure and favorable outcome compared with the Stoppa approach7-10. DESCRIPTION: The skin incision runs along the lateral border of the rectus abdominis muscle to develop the anterior rectus sheath. The retroperitoneal space lateral to the rectus abdominis muscle is entered and the inferior epigastric vessels and the round ligament in females or the spermatic cord in males are identified. The superior pubic ramus and the iliopectineal eminence are exposed. If the corona mortis vessels (a vascular anastomosis between the obturator vessels and the external iliac artery) are present, they are ligated. The obturator nerve and vessels are exposed. The dissection is then directed posteriorly under retraction of the external iliac vessels with further subperiosteal exposure of the pubic ramus, the quadrilateral plate, and the posterior column. Any nonessential iliolumbar vessels are ligated. Residual displacement is assessed with fluoroscopic views. For reduction of a medially displaced femoral head, longitudinal extremity soft tissue or lateral skeletal traction (optional), with a Schanz pin in the greater trochanter, is used. For disimpaction of acetabular dome fragments and grafting of a supra-acetabular void (optional), a fluoroscopy unit is used to assess reduction and identify the void; in addition, arthroscopy can be used. The scope is introduced through the fracture gap to check for reduction without any water or specific setup. For reduction and fixation of extra-articular components (iliac wing posteriorly and superior pubic ramus anteriorly), the posterior column, and the quadrilateral plate, the fluoroscopy unit is used. The anterior lamina of the rectus sheath is sutured, and a layered closure performed. ALTERNATIVES: The ilioinguinal or modified Stoppa approach might be used instead. RATIONALE: The Pararectus approach combines the advantages of the ilioinguinal approach and the Stoppa approach. The Pararectus approach facilitates surgical access directly above the hip joint, which is comparable with the access obtained through the second window of the ilioinguinal approach, but without dissection of the inguinal canal. Moreover, the Pararectus approach provides intrapelvic visualization that is at least equivalent to that offered by the Stoppa approach but without losing any direct access to the hip joint.

A meta-analysis of synovial biomarkers in periprosthetic joint infection: Synovasure™ is less effective than the ELISA-based alpha-defensin test.

PURPOSE: (1) To determine the overall accuracy of synovial alpha-defensin, synovial C-reactive protein (sCRP), interleukin-6 (sIL-6), and leukocyte esterase (sLE) as diagnostic markers for periprosthetic joint infection (PJI) and (2) to independantly evaluate the accuracy of both the laboratory-based ELISA alpha-defensin test and the Synovasure™ alpha-defensin test kit. METHODS: An EMBASE and MEDLINE (PubMed) database search was performed using a set of professionally set search terms. Two independent reviewers rated eligible articles. Sensitivity and specificity were meta-analysed using a bivariate random-effects model. RESULTS: Accuracy values were extracted from 42 articles. Pooled sensitivity and specificity of the represented biomarkers were: alpha-defensin ELISA 0.97 (95% CI 0.91-0.99) and 0.97 (95% CI 0.94-0.98), respectively; Synovasure™ test kit assay 0.80 (95% CI 0.65-0.89) and 0.89 (95% CI 0.76-0.96), respectively; sLE 0.79 (95% CI 0.67-0.87) and 0.92 (95% CI 0.87-0.92), respectively; sIL-6 0.76 (95% CI 0.65-0.84) and 0.91 (95% CI 0.88-0.94), respectively; sCRP 0.86 (95% CI 0.81-0.91) and 0.90 (95% CI 0.86-0.93), respectively. CONCLUSION: The labararory-based alpha-defensin ELISA test showed the highest ever reported accuracy for PJI diagnosis. However, this did not apply for the Synovasure™ alpha-defensin test, which was comparable in its overall diagnostic accuracy to sCRP, sIL-6 and sLE. The later biomarkers also did not yield an overall diagnostic accuracy higher than that previously reported for synovial white cell count (sWBC) or culture bacteriology. Based on current evidence, no synovial biomarker should be applied as a standalone diagnostic tool. Furthermore, the use of the laboratory-based alpha-defensin ELISA test should be encouraged, still, the Synovasure™ alpha-defensin test kit should be critically appreciated. LEVER OF EVIDENCE: III.

Surgical hip dislocation for removal of retained intra-articular bullets.

INTRODUCTION: Surgical hip dislocation with trochanteric osteotomy was introduced for the treatment of femoroacetabular impingement and other intra-articular pathologies of the hip. We expanded the indications to include removal of retained bullets in the hip joint as an alternative to hip arthroscopy. PATIENTS AND METHODS: We present a prospective case series of ten patients that were treated with a surgical hip dislocation for removal of retained bullets in the hip joint between January 2014 and October 2015 in a Level 1 trauma centre. The main outcome measurements were successful bullet removal, blood loss, surgical time and intraoperative complications. RESULTS: There were 8 males and 2 females with a mean age of mean age 27.3 years (range 20-32). All patients had one whole retained bullet for removal (right side: 8; left side: 2). In all cases the bullet could be removed in its entirety. The average surgical time was 73min (range 55-125) and the average blood loss 255ml (range 200-420). CONCLUSIONS: Surgical hip dislocation provides an unlimited view of the acetabulum and femoral head and neck and it therefore allows for easy removal of retained bullets. Osteocartilaginous lesions and concomitant fractures of the femoral head can be simultaneously evaluated and treated.

Novel organ-slice culturing system to simulate meniscal repair: Proof of concept using a synovium-based pool of meniscoprogenitor cells.

Meniscal injuries can occur secondary to trauma or be instigated by the changes in knee-joint function that are associated with aging, osteo- and rheumatoid arthritis, disturbances in gait, and obesity. Sixty percent of persons over 50 years of age manifest signs of meniscal pathology. The surgical and arthroscopic measures that are currently implemented to treat meniscal deficiencies bring only transient relief from pain and effect but a temporary improvement in joint function. Although tissue-engineering-based approaches to meniscal repair are now being pursued, an appropriate in-vitro model has not been conceived. The aim of this study was to develop an organ-slice culturing system to simulate the repair of human meniscal lesions in vitro. The model consists of a ring of bovine meniscus enclosing a chamber that represents the defect and reproduces its sequestered physiological microenvironment. The defect, which is closed with a porous membrane, is filled with fragments of synovial tissue, as a source of meniscoprogenitor cells, and a fibrin-embedded, calcium-phosphate-entrapped depot of the meniscogenic agents BMP-2 and TGF-ß1. After culturing for 2 to 6 weeks, the constructs were evaluated histochemically and histomorphometrically, as well as immunohistochemically, for the apoptotic marker caspase 3 and collagen types I and II. Under the defined conditions, the fragments of synovium underwent differentiation into meniscal tissue, which bonded with the parent meniscal wall. Both the parent and the neoformed meniscal tissue survived the duration of the culturing period without significant cell losses. The concept on which the in-vitro system is based was thus validated. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1588-1596, 2016.

The 100 Most Influential Publications in Cervical Spine Research.

STUDY DESIGN: Bibliometric study of current literature. OBJECTIVE: To identify and analyze the 100 most cited publications in cervical spine research. SUMMARY OF BACKGROUND DATA: The cervical spine is a dynamic field of research with many advances made within the last century. The literature has, however, never been comprehensively analyzed to identify and compare the most influential articles as measured by the number of citations. METHODS: All databases of the Thomson Reuters Web of Knowledge were utilized in a two-step approach. First, the 150 most cited cervical spine studies up to and including 2014 were identified using four keywords. Second, all keywords related to the cervical spine found in the 150 studies (n = 38) were used to conduct a second search of the database. The top 100 most cited articles were hereby selected for further analysis of current and past citations, authorship, geographic origin, article type, and level of evidence. RESULTS: Total citations for the 100 studies identified ranged from 173 to 879. They were published in the time frame 1952 to 2008 in a total of 30 different journals. Most studies (n = 42) were published in the decade 1991-2000. Level of evidence ranged from 1 to 5 with 39 studies in the level 4 category. A total of 13 researchers were first author more than once and nine researchers senior author more than once. The two-step approach with a secondary widening of search terms yielded an additional 27 studies, including the first ranking article. CONCLUSION: This bibliometric study is likely to include some of the most important milestones in the field of cervical spine research of the last 100 years.

Age-Independent Cartilage Generation for Synovium-Based Autologous Chondrocyte Implantation.

The articular cartilage layer of synovial joints is commonly lesioned by trauma or by a degenerative joint disease. Attempts to repair the damage frequently involve the performance of autologous chondrocyte implantation (ACI). Healthy cartilage must be first removed from the joint, and then, on a separate occasion, following the isolation of the chondrocytes and their expansion in vitro, implanted within the lesion. The disadvantages of this therapeutic approach include the destruction of healthy cartilage-which may predispose the joint to osteoarthritic degeneration-the necessarily restricted availability of healthy tissue, the limited proliferative capacity of the donor cells-which declines with age-and the need for two surgical interventions. We postulated that it should be possible to induce synovial stem cells, which are characterized by high, age-independent, proliferative and chondrogenic differentiation capacities, to lay down cartilage within the outer juxtasynovial space after the transcutaneous implantation of a carrier bearing BMP-2 in a slow-release system. The chondrocytes could be isolated on-site and immediately used for ACI. To test this hypothesis, Chinchilla rabbits were used as an experimental model. A collagenous patch bearing BMP-2 in a slow-delivery vehicle was sutured to the inner face of the synovial membrane. The neoformed tissue was excised 5, 8, 11 and 14 days postimplantation for histological and histomorphometric analyses. Neoformed tissue was observed within the outer juxtasynovial space already on the 5th postimplantation day. It contained connective and adipose tissues, and a central nugget of growing cartilage. Between days 5 and 14, the absolute volume of cartilage increased, attaining a value of 12 mm(3) at the latter juncture. Bone was deposited in measurable quantities from the 11th day onwards, but owing to resorption, the net volume did not exceed 1.5 mm(3) (14th day). The findings confirm our hypothesis. The quantity of neoformed cartilage that is deposited after only 1 week within the outer juxtasynovial space would yield sufficient cells for ACI. Since the BMP-2-bearing patches would be implanted transcutaneously in humans, only one surgical or arthroscopic intervention would be called for. Moreover, most importantly, sufficient numbers of cells could be generated in patients of all ages.

Activation of intervertebral disc cells by co-culture with notochordal cells, conditioned medium and hypoxia.

BACKGROUND: Notochordal cells (NC) remain in the focus of research for regenerative therapy for the degenerated intervertebral disc (IVD) due to their progenitor status. Recent findings suggested their regenerative action on more mature disc cells, presumably by the secretion of specific factors, which has been described as notochordal cell conditioned medium (NCCM). The aim of this study was to determine NC culture conditions (2D/3D, fetal calf serum, oxygen level) that lead to significant IVD cell activation in an indirect co-culture system under normoxia and hypoxia (2% oxygen). METHODS: Porcine NC was kept in 2D monolayer and in 3D alginate bead culture to identify a suitable culture system for these cells. To test stimulating effects of NC, co-cultures of NC and bovine derived coccygeal IVD cells were conducted in a 1:1 ratio with no direct cell contact between NC and bovine nucleus pulposus cell (NPC) or annulus fibrosus cells (AFC) in 3D alginate beads under normoxia and hypoxia (2%) for 7 and 14 days. As a positive control, NPC and AFC were stimulated with NC-derived conditioned medium (NCCM). Cell activity, glycosaminoglycan (GAG) content, DNA content and relative gene expression was measured. Mass spectrometry analysis of the NCCM was conducted. RESULTS: We provide evidence by flow cytometry that monolayer culture is not favorable for NC culture with respect to maintaining NC phenotype. In 3D alginate culture, NC activated NPC either in indirect co-culture or by addition of NCCM as indicated by the gene expression ratio of aggrecan/collagen type 2. This effect was strongest with 10% fetal calf serum and under hypoxia. Conversely, AFC seemed unresponsive to co-culture with pNC or to the NCCM. Further, the results showed that hypoxia led to decelerated metabolic activity, but did not lead to a significant change in the GAG/DNA ratio. Mass spectrometry identified connective tissue growth factor (CTGF, syn. CCN2) in the NCCM. CONCLUSIONS: Our results confirm the requirement to culture NC in 3D to best maintain their phenotype, preferentially in hypoxia and with the supplementation of FCS in the culture media. Despite these advancements, the ideal culture condition remains to be identified.

Mucosal Erosion of the Cricoid Cartilage After the Use of an i-Gel Supraglottic Airway Device in a Patient with Diffuse Idiopathic Skeletal Hyperostosis.

After standard hip arthroplasty, an 82-year-old patient with previously undiagnosed diffuse idiopathic skeletal hyperostosis of the cervical spine experienced life-threatening side effects after use of a supraglottic airway device (i-gel). Extensive mucosal erosion and denudation of the cricoid cartilage caused postoperative supraglottic swelling and prolonged respiratory failure requiring tracheostomy. In this case report, we highlight the importance of evaluating risk factors for failure of supraglottic airway devices.

Impact of advanced age on outcomes following damage control interventions for trauma.

BACKGROUND: Damage control (DC) strategy has significantly contributed to mortality reduction in massively bleeding and critically injured trauma victims. However, there is a lack of literature validating the effectiveness of this approach in the elderly population. METHODS: The trauma registry of a Level I trauma center was utilized to identify all severely injured patients [Injury Severity Score (ISS) ≥16] from January 1996 to December 2007 who underwent initial DC procedures. Patients with a head Abbreviated Injury Scale (AIS) ≥3 were excluded from the analysis. Demographics, clinical and physiological parameters, and in-hospital outcome measures were compared between elderly (≥55 years) and younger (<55 years) patient cohorts subjected to DC procedures. RESULTS: Overall, 158 patients met the inclusion criteria. Among them, 34 patients (21.5%) were aged ≥55 years (range 55-85 years) and 124 patients (78.5%) were <55 years old (range 16-54 years). The overall in-hospital mortality rate was 10.1% (n = 16) with a significantly higher mortality rate for elderly patients than for younger patients: 29.4% vs. 4.8%; adjusted P = 0.001; adjusted odds ratio (OR) with 95% confidence interval (CI) 7.09 (2.30-21.74). When stratified by DC subgroups, the case-fatality rate was significantly higher for the elderly patients who underwent extremity DC procedures [19.2% vs. 3.2%; adjusted P = 0.032; adjusted OR with 95% CI 5.95 (1.16-30.30)] and DC laparotomy [55.6% vs. 7.1%; P = 0.005; OR and 95% CI 16.25 (2.32-114.06)]. Both cohorts required massive transfusion during the initial 24 h of admission (18.9 ± 2.9 vs. 15.1 ± 1.6 units of packed red blood cells; P = 0.290). Nevertheless, there were no statistically significant differences between the two groups regarding hospital and surgical intensive care unit lengths of stay or major in-hospital complications. CONCLUSIONS: The mortality rate for elderly trauma patients undergoing DC is excessive at 29%. Despite the significant burden of injury and the massive transfusion requirement, most of the elderly patients subjected to DC survived and experienced in-hospital morbidity measures comparable to those of the younger patients. Our results provide further support for damage control intervention in severely injured elderly patients.