There is evidence that various anatomical structures have altered morphology with ageing, and anecdotal evidence of changing lumbar spinous process (LSP) morphology with age. This study aims to clarify the influence of age on LSP morphology, and on lumbar spine alignment. 200 CT scans of the abdomen were reformatted with bone windows allowing precise measurement of LSP dimensions and lumbar lordosis. Observers were blinded to patient demographics. Inter-observer reliability was confirmed. The smallest LSP is at L5. The male LSP is on average 2-3mm higher and 1mm wider than the female LSP. LSP height increases significantly with age at every level in the lumbar spine (P<10. -5. at L2). The LSPs increase in height by 2-5mm between 20-85 years of age (P<10. -6. ), which was as much as 31% at L5 (P<10. -8. ). Width increases proportionally more, by 3-4mm or greater than 50% at each lumbar level (P<10. -11. ). Lumbar lordosis decreases in relation to increasing LSP height (P<10. -4. ) but is independent of increasing LSP width (P=0.2). The height and width of the spinous processes increases with age. Increases in spinous process height are related to a loss of lumbar lordosis and may contribute to sagittal plane imbalance

The purpose of this study was to establish the relationship between the anterior and posterior spinal elements and identify which morphological changes in the ageing spine has the greatest influence in determining the loss of lumbar lordosis. Method. 224 patients' (98 male, 126 female) erect plain lumbar radiographs were reviewed. Lateral plane projections were used to measure the lumbar angle (lordosis), spinous process (SP) height, the interspinous gap (ISG) height, the mid-vertebral body (MVB) height and the mid inter-vertebral disc (MIVD) height of vertebral bodies L1 to L5. The relationship between the heights of these structures and their relative influence and effect on the lumbar angle was investigated using a multiple linear regression model. Results. SP, ISG, MVB and MIVD heights all had a statistically significant influence on determining the lumbar angle (p < 10. −3. ). All heights decreased with age except for the SP height (Graph 1). Age was associated with a decreasing lumbar angle (p 0.134) – (Graph 2). Increasing SP height had an inverse relationship on the lumbar angle. The increase in the SP height had the greatest influence on the lumbar angle (Beta coefficient of -0.71), whilst the MVB and MIVD heights had a lesser influence on determining the lumbar angle (Beta coefficients 0.29 and 0.53 respectively). Conclusion. This study demonstrates that the changing morphology of the SP height in the ageing lumbar spine has the greatest influence on determining the lumbar angle of our measured variables. The relative cumulative effect of the increase in the height of the posterior spinal elements has a greater influence on the loss of the lumbar angle than the cumulative loss of height in the anterior spinal elements in the ageing lumbar spine

Auckland City Hospital, Auckland, New Zealand. To show that the spinous processes (SPs) increase in size with age. To investigate the incidence of SP abutment, relationship to disc degeneration and age related kyphosis. Describe patterns of SP neoarticulation in relation to back pain and intersegmental axial rotation and deformity. We reviewed 200 Abdominal CTs, CT myelograms and 100 standing x-rays (age 18-90 years). We measured SP size, interspinous gap, patterns of neoarticulation, disc height, lumbar lordosis and axial rotation. We compared symptomatic and asymptomatic groups. A 30-50% increase in SP size coupled combined with a loss of disc height leads to increasing rates of SP abutment after the age of 35 years. 30% of people over the age of 60 years have SP abutment. There is a 15 degree increase in standing lumbar kyphosis with age. Four patterns of SP neoarticulation are seen. Degenerative changes in the SP articulation increase by more than 80% in a symptomatic cohort. Oblique SP articulation is 2.5 times more likely in symptomatic individuals and associated with a rotational intersegmental deformity. Ageing is accompanied by SP enlargement and abutment, contributing to a loss of lumbar lordosis. Patterns of neoarticulation and degeneration appear associated with back pain and rotational deformity

Purpose

To observe the safety and efficacy of a minimally destructive decompressive technique without fusion in patients with lumbar stenosis secondary to degenerative spondylolisthesis.

Posterior lumbar interbody fusion (PLIF) is indicated for many patients with pain and/or instability of the lumbar spine. We performed 36 PLIF procedures using the patient’s lumbar spinous process and laminae, which were inserted as a bone graft between two vertebral bodies without using a cage. The mean lumbar lordosis and mean disc height to vertebral body ratio were restored and preserved after surgery. There were no serious complications.

These results suggest that this procedure is safe and effective.

Aims. To report the development of the technique for minimally invasive lumbar decompression using robotic-assisted navigation. Methods. Robotic planning software was used to map out bone removal for a laminar decompression after registration of CT scan images of one cadaveric specimen. A specialized acorn-shaped bone removal robotic drill was used to complete a robotic lumbar laminectomy. Post-procedure advanced imaging was obtained to compare actual bony decompression to the surgical plan. After confirming accuracy of the technique, a minimally invasive robotic-assisted laminectomy was performed on one 72-year-old female patient with lumbar spinal stenosis. Postoperative advanced imaging was obtained to confirm the decompression. Results. A workflow for robotic-assisted lumbar laminectomy was successfully developed in a human cadaveric specimen, as excellent decompression was confirmed by postoperative CT imaging. Subsequently, the workflow was applied clinically in a patient with severe spinal stenosis. Excellent decompression was achieved intraoperatively and preservation of the dorsal midline structures was confirmed on postoperative MRI. The patient experienced improvement in symptoms postoperatively and was discharged within 24 hours. Conclusion. Minimally invasive robotic-assisted lumbar decompression utilizing a specialized robotic bone removal instrument was shown to be accurate and effective both in vitro and in vivo. The robotic bone removal technique has the potential for less invasive removal of laminar bone for spinal decompression, all the while preserving the spinous process and the posterior ligamentous complex. Spinal robotic surgery has previously been limited to the insertion of screws and, more recently, cages; however, recent innovations have expanded robotic capabilities to decompression of neurological structures. Cite this article: Bone Jt Open 2024;5(9):809–817

Posterior cervical wiring is commonly performed for patients with spinal instability, but has inherent risks. We report eight patients who had neurological deterioration after sublaminar or spinous process wiring of the cervical spine; four had complete injuries of the spinal cord, one had residual leg spasticity and three recovered after transient injuries. We found no relation between the degree of spinal canal encroachment and the severity of the spinal-cord injury, but in all cases neurological worsening appeared to have been caused by either sublaminar wiring or spinous process wiring which had been placed too far anteriorly. Sublaminar wiring has substantial risks and should be used only at atlantoaxial level, and then only after adequate reduction. Fluoroscopic guidance should be used when placing spinous process wires especially when the posterior spinal anatomy is abnormal

We describe the results of a prospective case series of patients with spondylolysis, evaluating a technique of direct stabilisation of the pars interarticularis with a construct that consists of a pair of pedicle screws connected by a U-shaped modular link passing beneath the spinous process. Tightening the link to the screws compresses bone graft in the defect in the pars, providing rigid intrasegmental fixation. We have carried out this procedure on 20 patients aged between nine and 21 years with a defect of the pars at L5, confirmed on CT. The mean age of the patients was 13.9 years (9 to 21). They had a grade I or less spondylolisthesis and no evidence of intervertebral degeneration on MRI. The mean follow-up was four years (2.3 to 7.3). The patients were assessed by the Oswestry Disability Index (ODI) and a visual analogue scale (VAS). At the latest follow-up, 18 patients had an excellent clinical outcome, with a significant (p < 0.001) improvement in their ODI and VAS scores. The mean ODI score at final follow-up was 8%. Assessment of the defect by CT showed a rate of union of 80%. There were no complications involving the internal fixation. The strength of the construct removes the need for post-operative immobilisation

To describe a modification of the existing technique for C2 translaminar screw fixation that can be used for salvage in difficult cases. Bilateral crossing C2 laminar screws have recently become popular as an alternative technique for C2 fixation. This technique is particularly useful in patients with anomalous anatomy, as a salvage technique where other modes of fixation have failed or as a primary procedure. However, reported disadvantages of this technique include breach of the dorsal lamina and spinal canal, early hardware failure and difficulty in bone graft placement due to the position of the polyaxial screw heads. To address some of these issues, a modified technique is described. In this technique, the upper part of the spinous process of C2 is removed and the entry point of the screw is in the base of this removed spinous process. From October 2008 to March 2009, 6 patients underwent insertion of unilateral translaminar screws using our technique. The indications were: basilar invagination(three cases), C1/C2 fracture (two cases), tumour (one case). Age varied from 22 to 81 years (mean 48 years). All patients had post-operative x-ray and CT scan to assess position of the screws. Mean follow-up was 6 months. The screw position was satisfactory in all patients. There were no intraoperative or early postoperative complications. Our modification enables placement of bone graft on the C2 lamina and is also less likely to cause inadvertent cortical breach. Because of these advantages, it is especially suitable for patients with advanced rheumatoid arthritis with destruction of the lateral masses of C2 or as part of a hybrid construct in patients with unilateral high riding vertebral artery. This technique is not suitable for bilateral translaminar screw placement

Introduction. Chronic low back pain (LBP) is globally recognised as a leading cause of disability, with a global point-prevalence of 540 million people experiencing ‘activity-limiting’ LBP. A lack of muscle endurance is common in people with LBP, however the mechanisms underlying reduced endurance remain unclear. This study utilised high-density EMG (HDEMG) to evaluate differences in the spatial distribution and redistribution of lumbar erector spinae (ES) activity during an endurance task. Methods. Thirteen control (Age:26.46±5.0, 7 Males) and 13 LBP participants (Age:27.39±9.7, 6 Males) were recruited and HDEMG signals were detected from ES unilaterally using a 13×5 electrode grid adhered 2cm lateral to the L5 spinous process. Participants were asked to complete an isometric endurance task until failure (>10° trunk deviation) with muscle activity simultaneously recorded. The activity was computed to form a map of the EMG amplitude distribution and the position of the centre of activity (centroid) was monitored throughout the task. Results. The LBP group showed significantly lower endurance than controls (LBP:186.2±72.3s, control:283.0±33.0s). The EMG map showed a less diffuse contraction of ES in LBP participants, with greater activation in cranial portions. In the LBP group, throughout the task the centroid was 12mm more cranial, and less redistribution of activity was seen (LBP:1.40±0.29mm, control:2.10±0.45mm). Conclusions. LBP participants utilised a different motor strategy to complete the task, characterised by more cranial activation of ES and less redistribution of activity. These findings provide new insight into the mechanisms underlying impaired endurance in people with LBP and may lead to the development of new exercise approaches. Conflicts of interest: No conflicts of interest. Sources of funding: No funding obtained

We describe the results of a prospective case series to evaluate a technique of direct pars repair stabilised with a construct that consists of a pair of pedicle screws connected with a u-shaped modular link that passes beneath the spinous process. Tightening the link to the screws compresses the bone grafted pars defect providing rigid intrasegmental fixation. 20 patients aged between 9 and 21 years with a pars defect at L5 confirmed on computed tomography (CT) were included. The average age of the patients was 13.9 years. The eligible patient had Grade I or less spondylolisthesis and no evidence of intervertebral degeneration on MRI. The average duration of follow-up was 4 years. Clinical assessments for all patients was via the Oswestry disability index (ODI) and visual analogue scores (VAS). At the latest follow-up, 18 of the 20 patients had excellent clinical outcomes with a significant (p<0.001) improvement in their ODI and VAS scores with a mean post-operative ODI score of 8%. Fusion of the pars defect as assessed by CT showed fusion rates of 80%. There were no hardware complications. The strength of the construct obviates the need for post-operative immobilisation

Our study aims to evaluate the efficacy of Wallis implant in management of discogenic back pain. We have prospectively studied thirty patients between 2006 and 2007. Average age of patients was 40.8 years. Average follow-up period 20.6 months (9-28). Main inclusion criteria includes failure of conservative management of low back pain due to degenerative disc disease, preservation of 50% of the disc height and positive discographic features. In majority of the patients the implant was put in at the level of L4-L5. Pre-op and post op SF36 and Oswestry Disability Index (ODI) scores were assessed during clinic follow-up and by telephonic interview. Mean SF36 score improved from thirty-seven (8.3 – 54.3) to 51.4. Mean ODI improved from forty-three (20-60) to 26.5(2-60) (p = 0.026). Complications including superficial infection occurred in one patient, deep infection in one patient, erosion of spinous process in one and displacement of the implant in one case. Three (10%) patients had revision surgery due to various reasons. Wallis interspinous dynamic stabilization system could be used as a soft stabilisation device avoiding fusion and short-term results are promising. In selected group of discogenic low back pain patients it is a useful interim procedure. Long-term follow-up of our series is ongoing

Background. Several theories have been put forward with respect to the mechanical role of the thoracolumbar fascia (TLF) but none have been substantiated in part due to an inability to explore its function in vivo. This study explored the use of ultrasound to image the layers of the TLF in vivo. Methods. Initially a cadaveric dissection of the fascia was performed to gain an appreciation of the 3-D orientation and representation of the TLF in the lumbar region. A conventional ultrasound system (Diasus, Dynamic Imaging Ltd) was then used to image the 3 layers of the fascia on 40 normal subjects (18 males and 22 females, mean age 27.3±5.8 years) and the reliability of these measures was investigated on a subset of this population. Results. Using ultrasound, the posterior and middle layer of the TLF could be readily identified, however it was not possible to visualise the anterior layer due to the limitations of the scanner used. The thickness of the posterior layer ranged from 1.3 ±0.4 to 1.5±0.4 mm depending on location relative to the spinous process. The middle layer tended to be thinner being 1.0±0.4mm on average. Intra-observer errors were within acceptable ranges, although not ideal. Conclusion. Ultrasound may be an important tool for understanding the mechanical role of fascia, however this would necessitate the use of high resolution scanner to enhance the reliability of images. Further work is required to image changes in the presentation of fascia in different loaded functional positions

Spinal fusion, ending caudally at L5 rather than at the sacrum, is recommended for selected patients with scoliosis due to Duchenne muscular dystrophy. We present a retrospective review of 48 patients operated on for this condition. Patients having spinal curvature with a Cobb angle of less than 40° and with less than 10° between a line tangential to the superior margins of both iliac crests and a line perpendicular to the spinous processes of L4 and L5, were fused to L5 (38 patients); patients not meeting these criteria were fused to the sacrum (10 patients). Spinal and sitting obliquity increased in patients fused to L5, rather than to the sacrum, but the severity of the worsening obliquity was significantly greater in patients in whom the apex of the curve was below L1. Two of the ten latter patients required revision procedures for worsening obliquity when their pulmonary function deteriorated to less than 25% of predicted values. We recommend fusion to the sacrum for scoliosis in Duchenne muscular dystrophy, especially for patients with an apex to their curve below L1

8 patients with cervical myelopathy treated by French-door laminoplasty and internal fixation. A novel technique of fixation is employed to provide immediate stability, pain relief and rapid mobilisation. To report the clinical and radiological outcomes of this new fixation device for French–door laminoplasty with minimum follow-up of 30 months. Hardware assisted laminoplasty has the potential advantage of instant stability and prevention of recurring stenosis. The use of titanium mini-plates has been described in open-door laminoplasty and now we describe this technique in French–door laminoplasty. 8 patients with cervical myelopathy secondary to congenital stenosis (2) and multi-level spondylotic myelopathy (6) underwent 2-4 level French–door laminoplasty and mini-plate fixation. The average follow-up was 46.5 months. Autogenous iliac crest bone graft was interposed between the sagittally split spinous processes and 16-18 holed titanium mini-plates were contoured into a trapezoidal shape and secured to the posterior elements with screws. Patients then mobilised without external support. The mean follow-up was 46.5 months. The mean improvement in NDI at final follow-up was 35% and mean improvement in VAS was 4 points. JOA score improved from a mean of 10 to a mean of 14.8 post-operatively. All patients had achieved a significant neurological improvement and pain relief. There were no post-operative hardware related complications, pseudarthrosis or neurological deterioration. French-door laminoplasty is an excellent alternative to laminectomy for treatment of young patients with cervical myelopathy. The use of titanium mini-plates not only provides instant stability and pain relief but also seems to minimize the risk of C5 nerve root palsy. Internal fixation appears to provide instant stability, early mobilisation and therefore reduces hospital stay and associated costs

We carried out a prospective study looking at the functional outcome and post-procedure segmental instability after lumbar decompression using a flip osteotomy technique that involved unilateral subperiosteal muscle dissection with hinging of the spinous processes thereby preserving the integrity of the posterior elements for unilateral or bilateral lumbar spine decompression. Between February 2007 and February 2008, 51 patients (29 male and 22 female) diagnosed with degenerative and congenital lumbar stenosis with an average age of 60, underwent central and lateral canal decompression using the flip osteotomy technique. An average of two segments (range 1-3 segments) was decompressed. Patients with a history of previous spinal surgery, spinal fusion, existing degenerative spondylolisthesis or cauda equina syndrome were excluded. All patients were followed up for a mean of 1.5 years. Five outcome measures were used – visual analogue scale for pain, Likert scale for functional status, symptom specific well-being score, general well-being score, number of days incapacitated in last 4 weeks. The outcomes measures were recorded pre-operatively, 6 weeks and one year post-operatively. Successful surgical outcome was defined as an improvement in at least four out of five outcome measures. 90% (46 patients) of patients had a successful surgical outcome. There was a statistically significant improvement in all outcome criteria (p<0.005) at the 6-week post-operative mark as compared to pre-operatively, with marginal improvement at one year post-surgery. There was no evidence of progressive lumbar segmental instability at one year post-operatively using our flip osteotomy technique. Decompression of the lumbar spine for lumbar stenosis using the flip osteotomy technique is a safe approach for one or multi-level stenosis with good outcomes and no evidence of significant iatrogenic segmental spinal instability. We declare no conflict of interest and ethical approval was obtained

The objective of this study was to assess the reliability and appropriateness of statistical shape modelling for capturing variation in thoracic vertebral anatomy for future use in assessing scoliotic vertebral morphology. Magnetic resonance (MR) images of the thoracic vertebrae were acquired from 20 healthy adults (12 female, 8 male) using a 1.5 T MR scanner (Intera, Philips). A T1 weighted spin-echo sequence (repetition time = 294 ms, echo time = 8 ms, number of signal averages = 3) was used. A set of slices (number = 27, thickness = 1.9 mm, gap = 1.63 mm, pixel size = 0.5 mm) were acquired for each vertebrae, parallel to the mid-transverse plane of the vertebral body. Repeated imaging, including participant repositioning, was performed for T4, T8 and T12 to assess reliability. Landmark points were placed on the images to define anatomical features consisting of the vertebral body and foramen, pedicles, transverse and spinous processes, inferior and superior facets. A statistical shape model was created using software tools developed in MATLAB (R2013a, The MathWorks Inc.). The model was used to determine the mean vertebral shape and ‘modes of variation’ describing patterns in vertebral shape. Analysis of variance was used to test for differences between vertebral levels and subjects and reliability was assessed by determining the within-subject standard deviation from the repeated measurements. The first three modes of variation, shown below (green = mean, red and blue = ±2 standard deviations about the mean), accounted for 70% of the variation in thoracic vertebral shape (Mode 1 = 44%, Mode 2 = 19%, Mode 3 = 4%). Visual inspection indicated that these modes described variation in anatomical features such as the aspect ratio of the vertebral bodies, width and orientation of the pedicles, and position and orientation of the processes and facet points. Variation in shape along the thoracic spine, characterised by these modes of variation, was consistent with that reported in the literature. Significant differences (p< 0.05) between vertebral levels and between some subjects were found. The reliability of the method was good with low relative error (Mode 1 = 5%, Mode 2 = 8%, Mode 3 = 19%). Statistical shape modelling provides a reliable method for characterizing many anatomical features of the thoracic vertebrae in a compact number of variables. This is useful for robustly assessing morphological differences between scoliotic and non-scoliotic vertebrae and in assessing entry points and trajectories for pedicle screws

Statement of Purpose. The purpose of this experiment was to characterize the biomechanical properties of a minimally-invasive flexion-restricting stabilization system (FRSS) developed to address flexion instability. Background. Lumbar flexion instability is associated with degenerative pathology such as degenerative spondylolisthesis (DS) as well as resection of posterior structures during neural decompression. Flexion instability may be measured by increased total flexion/extension range of motion (ROM), as well as reduced stiffness within the high flexibility zone (HFZ, the range in which most activities occur). Flexion and segmental translation are known to be coupled; therefore increased flexion may exacerbate translational instability, particularly in DS. Method. Five cadaveric lumbar spines were tested intact; after L4-L5 destabilization including nucleotomy and midline decompression; and following restabilization with the FRSS secured to the spinous processes. Specimens were loaded in flexion (8Nm) and extension (6Nm) under 400N compressive follower preload. Flexion stiffness in the HFZ and segmental translation were also measured. Results. Destabilization increased L4-L5 flexion by 69%±31% (p<.01); decreased HFZ flexion stiffness 56%±12% (p=.01) and increased segmental translation 70%±49% from 1.5±0.4mm to 2.4±0.4mm (p<.01). With the FRSS segmental flexion was reduced by 45%±15% (p<.01); average HFZ flexion stiffness was increased by 232%±104% (p<.01); and segmental translation was reduced by 25%±9% to 1.8±0.2mm (p<.01). These values were not significantly different from the intact condition (p=.54, p=.21, p=.19). Discussion and Conclusion. The destabilization modeled here simulated degenerative and iatrogenic destabilizations often seen clinically. Implantation of the FRSS on the destabilized segments restored flexion, stiffness and translation to intact levels. The segmental coupling of translation and flexion seen in this experiment indicates that translation may be manipulated by altering flexion kinematics. The FRSS represents a novel system for treating flexion and translational instabilities

Aims

This study aimed to evaluate rasterstereography of the spine as a diagnostic test for adolescent idiopathic soliosis (AIS), and to compare its results with those obtained using a scoliometer.

Aims

The aim of this study was to assess the accuracy of pedicle screw placement, as well as intraoperative factors, radiation exposure, and complication rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic-navigated spinal surgery using a contemporary system.