Undecalcified Bone Preparation for Histology, Histomorphometry and Fluorochrome Analysis

Undecalcified bone histology demonstrates the micro-architecture of bone. It shows both the mineralised and cellular components of bone, which provides vital information on bone turnover or bone formation and resorption. This has tremendous importance in a variety of clinical and research applications. It yields beautiful images1 and allows for techniques such as fluorochrome assessment and histomorphometry2. Fluorochrome analysis is a technique where fluorescent dyes that bind to calcium are injected at a particular time point, which allows for quantification of the amount of mineralisation at that given time. Histomorphometry is a process of bone quantification at the microscopic level

A Review of Animal Models of Intervertebral Disc Degeneration: Pathophysiology, Regeneration, and Translation to the Clinic

Lower back pain is the leading cause of disability worldwide. Discogenic pain secondary to intervertebral disc degeneration is a significant cause of low back pain. Disc degeneration is a complex multifactorial process. Animal models are essential to furthering understanding of the degenerative process and testing potential therapies. The adult human lumbar intervertebral disc is characterized by the loss of notochordal cells, relatively large size, essentially avascular nature, and exposure to biomechanical stresses influenced by bipedalism. Animal models are compared with regard to the above characteristics. Numerous methods of inducing disc degeneration are reported. Broadly these can be considered under the categories of spontaneous degeneration, mechanical and structural models. The purpose of such animal models is to further our understanding and, ultimately, improve treatment of disc degeneration. The role of animal models of disc degeneration in translational research leading to clinical trials of novel cellular therapies is explored

The role of progenitor stem cells in promoting cervical interbody fusio

Anterior cervical discectomy and fusion accounts for up to forty percent of all spinal fusion procedures and is the most common surgical approach employed for treating cervical spondylosis or discopathies. These conditions may cause pain, weakness and sensory disturbance collectively termed radiculopathy due to nerve root compression. If the spinal cord is compressed, cervical myelopathy may result. Cervical myelopathy causes progressive neurological symptoms such as disturbance of gait or hand dexterity, which are the most devastating sequelae of degenerative disc disease. If conservative measures have failed, anterior cervical discectomy may be indicated as it decompresses the neural elements. Following the discectomy however, the void in the interbody space needs to be stabilised and there are several options for doing this. Iliac crest autograft bone has traditionally been the gold standard graft material for cervical fusion, however it is associated with the potential for donor site morbidity. Alternatives, such as synthetic bone graft substitutes and cadaver bone allograft, have limited osteo-inductive properties and, whilst they avoid donor site morbidity, they can result in inferior fusion rates compared with autograft. Use of allograft has also been associated with graft rejection, resorption, infection and collapse. Bone substitutes are osteoconductive per se; meaning they provide a matrix into which local cells including endogenous mesenchymal stem cells (MSCs), blood borne cells and osteoblasts can integrate and produce bone. Endogenous MSCs are reduced with age, a factor that can reduce bone fusion. Fusion rates may be decreased in about forty percent of patients undergoing multilevel surgery or with conditions such as rheumatoid arthritis, smoking or using anti-inflammatory medications. Non-union or pseudoarthrosis following anterior cervical discectomy can result in recurrent radiculopathy and neck pain which may require reoperation. Recombinant bone morphogenetic proteins (rhBMPs) have been used as osteo-inductive agents aimed at increasing cervical interbody fusion rates, but have been reported to result in life threatening complications, including airway and neurological compression. There is a need, therefore, for agents that can safely and effectively increase cervical fusion rates. The studies in this thesis aimed at investigating the potential of allogeneic mesenchymal precursor cells (MPCs) and amnion epithelial cells (AECs) in promoting cervical interbody fusion. Both of these progenitor cells have previously been shown to have osteogenic potential. The MPCs are a pure monocloncal cell population derived by immunoselection and were provided by Mesoblast. The AECs were derived by our group and offer the advantage of non invasive collection and no ethical issues. Preclinical studies were undertaken in the ovine cervical model, as this is a wellestablished model with anatomical, biomechanical and radiological similarities to the human cervical spine. These studies were designed to comply with regulatory requirements so that rapid translation to human clinical trials could follow. Fusion rate and quality as well as safety both systemically and at the fusion site were assessed using outcome measures which included plain and functional radiography, computerised tomography, chemical pathology, gross and microscopic pathology, histology, histomorphometry, fluorochrome analysis and biomechanical assessment. The preclinical studies revealed that the MPCs resulted in increased fusion rates compared to controls with bone substitute or autograft. Two doses of MPCs were tested and compared and no significant differences were found between doses. The study conducted using AECs did not result in significant fusion. A clinical study protocol was then designed and submitted for human ethics approval, which was granted. A clinical study has now commenced based on the results obtained in the preclinical studies, using MPCs

'Talk and Die' patients presenting to a major trauma centre over a 10 year period: A critical review

'Talk and die patients' describes a small number of patients who present with a mild head injury (Glasgow Coma Scale [GCS] 13-15) and then subsequently deteriorate and die from intracranial causes. We analysed the medical records of all those adult patients whose primary diagnosis as the cause of death was head injury, as determined by the coroner, who were admitted to a major Australian trauma centre between January 1994 and December 2003 (a 10-year period). The clinical profile of those patients who fulfilled the criteria of 'talk and die' were documented, including age, mode of injury, initial GCS, lucid interval, CT scan reports, operation performed, postmortem findings and intracranial cause of death. Factors considered potentially contributory to the patients' deterioration, such as delays in CT scanning or patient transfer, coagulopathy or hypoxic episodes were also noted. The incidence of 'talk and die' patients was 2.6% (15 out of 569) overall and the annual incidence did not significantly alter over the 10-year period of the study. The small number of patients precludes inferences regarding causal relationships, although potentially preventable factors, which could have been contributory to patient deterioration, were identified

A Review of Animal Models of Intervertebral Disc Degeneration:Pathophysiology, Regeneration, and Translation to the Clinic

Lower back pain is the leading cause of disability worldwide. Discogenic pain secondary to intervertebral disc degeneration is a significant cause of low back pain. Disc degeneration is a complex multifactorial process. Animal models are essential to furthering understanding of the degenerative process and testing potential therapies. The adult human lumbar intervertebral disc is characterized by the loss of notochordal cells, relatively large size, essentially avascular nature, and exposure to biomechanical stresses influenced by bipedalism. Animal models are compared with regard to the above characteristics. Numerous methods of inducing disc degeneration are reported. Broadly these can be considered under the categories of spontaneous degeneration, mechanical and structural models. The purpose of such animal models is to further our understanding and, ultimately, improve treatment of disc degeneration. The role of animal models of disc degeneration in translational research leading to clinical trials of novel cellular therapies is explored

Cell-Based Therapies Used to Treat Lumbar Degenerative Disc Disease: A Systematic Review of Animal Studies and Human Clinical Trials

Low back pain and degenerative disc disease are a significant cause of pain and disability worldwide. Advances in regenerative medicine and cell-based therapies, particularly the transplantation of mesenchymal stem cells and intervertebral disc chondrocytes, have led to the publication of numerous studies and clinical trials utilising these biological therapies to treat degenerative spinal conditions, often reporting favourable outcomes. Stem cell mediated disc regeneration may bridge the gap between the two current alternatives for patients with low back pain, often inadequate pain management at one end and invasive surgery at the other. Through cartilage formation and disc regeneration or via modification of pain pathways stem cells are well suited to enhance spinal surgery practice. This paper will systematically review the current status of basic science studies, preclinical and clinical trials utilising cell-based therapies to repair the degenerate intervertebral disc. The mechanism of action of transplanted cells, as well as the limitations of published studies, will be discussed

Potential Applications for Using Stem Cells in Spine Surgery

Abstract: While the use of biologics as adjuncts for spine surgery is growing annually stem cells have yet to be approved for this clinical application. Stem cells have the unique ability to differentiate into a variety of musculoskeletal tissues including bone or cartilage. Moreover they have been shown to secrete growth factors that promote matrix repair and regeneration and can down regulate inflammation and immune cell functions. It is these combined activities that make stem cells attractive candidates for advancing current techniques in spine surgery and possibly mitigating those pathologies responsible for tissue degeneration and failure thereby minimising the need for surgical intervention at a later date. This review focuses on the characteristics of progenitor cells from different sources and explores their potential as adjuncts for both current and future applications in spine surgery. Where possible we draw on the experimental outcomes from our own preclinical studies using adult mesenchymal progenitor stem cells, as well as related studies by others to support our contention that stem cell based therapies will play a significant role in spine surgery in the future

Anterior Cervical Discectomy and Fusion in the Ovine Model

Anterior cervical discectomy and fusion (ACDF) is the most common surgical operation for cervical radiculopathy and/or myelopathy in patients who have failed conservative treatment1,5. Since the operation was first described by Cloward2 and Smith and Robinson6 in 1958, a variety refinements in technique, graft material and implants have been made3. In particular, there is a need for safe osteoinductive agents that could benefit selected patients. The ovine model has been shown to have anatomical, biomechanical, bone density and radiological properties that are similar to the human counterpart, the most similar level being C3/44. It is therefore an ideal model in which preclinical studies can be performed. In particular this methodology may be useful to researchers interested in evaluating different devices and biologics, including stem cells, for potential application in human spinal surgery

Predictors of improvement in quality of life at 12-month follow-up in patients undergoing anterior endoscopic skull base surgery

Background: Patients with pituitary lesions experience decrements in quality of life (QoL) and treatment aims to arrest or improve QoL decline. Objective: To detect associations with QoL in trans-nasal endoscopic skull base surgery patients and train supervised learning classifiers to predict QoL improvement at 12 months. Methods: A supervised learning analysis of a prospective multi-institutional dataset (451 patients) was conducted. QoL was measured using the anterior skull base surgery questionnaire (ASBS). Factors associated with QoL at baseline and at 12-month follow-up were identified using multivariate logistic regression. Multiple supervised learning models were trained to predict postoperative QoL improvement with five-fold cross-validation. Results: ASBS at 12-month follow-up was significantly higher (132.19,SD = 24.87) than preoperative ASBS (121.87,SD = 25.72,p\u3c0.05). High preoperative scores were significantly associated with institution, diabetes and lesions at the planum sphenoidale / tuberculum sella site. Patients with diabetes were five times less likely to report high preoperative QoL. Low preoperative QoL was significantly associated with female gender, a vision related presentation, diabetes, secreting adenoma and the cavernous sinus site. Top quartile change in postoperative QoL at 12-month follow-up was negatively associated with baseline hypercholesterolemia, acromegaly and intraoperative CSF leak. Positive associations were detected for lesions at the sphenoid sinus site and deficient preoperative endocrine function. AdaBoost, logistic regression and neural network classifiers yielded the strongest predictive performance. Conclusion: It was possible to predict postoperative positive change in QoL at 12-month follow-up using perioperative data. Further development and implementation of these models may facilitate improvements in informed consent, treatment decision-making and patient QoL