Diurnal changes in the loads acting on the spine affect the water content and height of the intervertebral discs. We have reviewed the effects of these changes on spinal mechanics, and their possible clinical significance. Cadaveric lumbar spines subjected to periods of creep loading show a disc height change similar to the physiological change. As a result intervertebral discs bulge more, become stiffer in compression and more flexible in bending. Disc tissue becomes more elastic as its water content falls, and its affinity for water increases. Disc prolapse becomes more difficult. The neural arch and associated ligaments resist an increasing proportion of the compressive and bending stresses acting on the spine. Observations on living people show that these changes are not fully compensated for by modified muscle activity. We conclude that different spinal structures are more heavily loaded at different times of the day. Therefore, the time of onset of symptoms and signs, and any diurnal variation in their severity, may help us understand more about the pathophysiology of low back pain and sciatica

1. Excision of a lumbar intervertebral disc protrusion is required in only a small proportion of patients with this lesion. 2. A careful clinical and radiological examination of cases of lumbago and pain in the lower limb provides good evidence not only of the presence of a lumbar intervertebral disc protrusion but also of its anatomical level, size and relationships. Such examination is essential for the selection of the patients requiring surgical treatment. 3. In most of these selected cases, a carefully performed operation designed to relieve the affected nerve fibres from forces which stretch and compress them will give satisfying relief of symptoms. In the series reported, 92 per cent of patients were either completely free from symptoms or very greatly improved after operation. 4. The spinal and tension signs present before operation largely disappeared after it. Persistence of a pre-operative neurological deficit after operation is, however, relatively frequent, though seldom disabling. 5. The incidence of post-operative recurrence of symptoms of such severity as to indicate re-operation in the series was 2 per cent

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Cauda equina syndrome (CES) can be associated with chronic severe lower back pain and long-term autonomic dysfunction. This study assesses the recently defined core outcome set for CES in a cohort of patients using validated questionnaires.

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The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB.

1. A review of 204 cases of prolapsed intervertebral disc treated by the author by operation ten to twenty-five years before is presented. Injury was an etiological factor in only 14 per cent. 2. The decision to operate should be made after a clearly defined and controlled, but limited, period of closed treatment. The patients should not have to wait for operation. Treatment by closed methods should not be continued in the absence of detectable signs of improvement. Continuation under such circumstances delays recovery from paralysis, prolongs convalescence and delays return to work. Persistence of paraesthesia and numbness are other probable consequences of such delay. 3. A central disc prolapse is an indication for urgent operation if persistent sphincter disturbance or incomplete bladder evacuation is to be avoided. 4. A recurrence rate of sciatica less frequent than that associated with treatment by closed methods is noted in this and other reported series. True recurrence, as opposed to a prolapse at another level, is rare and is most probably due to continuation of the biochemical process of degeneration leading to further sequestration of disc tissue. On the other hand, the altered spinal mechanics, particularly local rigidity resulting from enucleation of a deranged intervertebral disc, may predispose to prolapse at a higher level or may themselves be the cause of symptoms of "recurrence". 5. Operation gives early and lasting relief of sciatic pain, reduces the need for the subsequent use of a corset and assists the patient to an early return to work. 6. Operation does not affect the decision to change work. This is decided by the length of history before operation and the amount of disc degeneration; and the need to change work is the same whether the patient is treated by closed means or by operation. 7. Apart from simple back raising exercises to strengthen the spinal extensor muscles, no physiotherapy need be given because it is not likely to improve the prognosis. 8. Backache is the most frequent disability after operation (17 per cent) and is related to the degree of degenerative change present before and after operation. Injury precipitated the onset of backache in three cases. Operation does not by itself produce backache. The amount of bone removed has no demonstrable effect on the late results of operation, nor on the subsequent development of degenerative changes. 9. Enucleation of the nucleus is not followed by fibrous ankylosis across the intervertebral space

In recent years, machine learning (ML) and artificial neural networks (ANNs), a particular subset of ML, have been adopted by various areas of healthcare. A number of diagnostic and prognostic algorithms have been designed and implemented across a range of orthopaedic sub-specialties to date, with many positive results. However, the methodology of many of these studies is flawed, and few compare the use of ML with the current approach in clinical practice. Spinal surgery has advanced rapidly over the past three decades, particularly in the areas of implant technology, advanced surgical techniques, biologics, and enhanced recovery protocols. It is therefore regarded an innovative field. Inevitably, spinal surgeons will wish to incorporate ML into their practice should models prove effective in diagnostic or prognostic terms. The purpose of this article is to review published studies that describe the application of neural networks to spinal surgery and which actively compare ANN models to contemporary clinical standards allowing evaluation of their efficacy, accuracy, and relatability. It also explores some of the limitations of the technology, which act to constrain the widespread adoption of neural networks for diagnostic and prognostic use in spinal care. Finally, it describes the necessary considerations should institutions wish to incorporate ANNs into their practices. In doing so, the aim of this review is to provide a practical approach for spinal surgeons to understand the relevant aspects of neural networks.

Cite this article: Bone Joint J 2021;103-B(9):1442–1448.

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To describe the clinical, radiological, and functional outcomes in patients with isolated congenital thoracolumbar kyphosis who were treated with three-column osteotomy by posterior-only approach.

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Although lumbosacral transitional vertebrae (LSTV) are well-documented, few large-scale studies have investigated thoracolumbar transitional vertebrae (TLTV) and spinal numerical variants. This study sought to establish the prevalence of numerical variants and to evaluate their relationship with clinical problems.

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To report the outcome of spinal deformity correction through anterior spinal fusion in wheelchair-bound patients with myelomeningocele.

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Whether to perform hybrid surgery (HS) in contrast to anterior cervical discectomy and fusion (ACDF) when treating patients with multilevel cervical disc degeneration remains a controversial subject. To resolve this we have undertaken a meta-analysis comparing the outcomes from HS with ACDF in this condition.

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The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort.

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To determine the effectiveness of prone traction radiographs in predicting postoperative slip distance, slip angle, changes in disc height, and lordosis after surgery for degenerative spondylolisthesis of the lumbar spine.

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To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability.

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Femoroacetabular impingement (FAI) is a potential cause of hip osteoarthritis (OA). The purpose of this study was to investigate the expression profile of matrix metalloproteinases (MMPs) in the labral tissue with FAI pathology.

1. A case of calcification in the intervertebral discs of a child is described. 2. The difference in the condition as it affects children and adults is discussed. 3. The etiology is considered but no definite conclusion is suggested

A description is given of a mutation in the mouse which reduces the size of the nucleus pulposus in the intervertebral disc of the adults. The discs of these mice show greatly accelerated age changes. The consequences of a similar mutation in man are discussed

1. On the basis of radiographic studies the incidence of degenerative change in the intervertebral disc in primitive squatting populations is considerably less than that found in civilised peoples. 2. The suggestion is made that lordosis is implicated in the pathogenesis of degeneration, but further studies are required

1. Pyogenic infection of the intervertebral disc in fifteen patients is described. 2. The importance of certain radiological signs in establishing the diagnosis is discussed. 3. Delayed diagnosis is believed to be responsible for the high incidence of paraplegia in this condition. 4. The place of operation in the management of this lesion is considered

1. Ten patients are described in whom pain due to arterial obstruction simulated pain caused by bone or joint disease or by disorder of the intervertebral disc. 2. The importance is stressed of arterial obstruction at the aortic bifurcation or in the iliac vessels as a possible cause of pain in patients attending orthopaedic clinics