Objectives. Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine. Methods. A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion. Results. Peak anterior longitudinal ligament (ALL) strain ranged from 0.106 to 0.382 in a normal spine, and from 0.116 to 0.399 in a fused cervical spine. Strain increased from cranial to caudal levels. The mean strain increase in the motion segment immediately adjacent to the site of fusion from C2-C3 through C5-C6 was 26.1% and 50.8% following single- and two-level cervical fusion, respectively (p = 0.03, unpaired two-way t-test). Peak cervical strains following various lumbar-fusion procedures were 1.0% less than those seen in a healthy spine (p = 0.61, two-way ANOVA). Conclusion. Cervical arthrodesis increases peak ALL strain in the adjacent motion segments. C3-4 experiences greater changes in strain than C6-7. Lumbar fusion did not have a significant effect on cervical spine strain. Cite this article: H. Huang, R. W. Nightingale, A. B. C. Dang. Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study. Bone Joint Res 2018;7:28–35. DOI: 10.1302/2046-3758.71.BJR-2017-0100.R1

We conducted a prospective follow-up MRI study of originally asymptomatic healthy subjects to clarify the development of Modic changes in the cervical spine over a ten-year period and to identify related factors. Previously, 497 asymptomatic healthy volunteers with no history of cervical trauma or surgery underwent MRI. Of these, 223 underwent a second MRI at a mean follow-up of 11.6 years (10 to 12.7). These 223 subjects comprised 133 men and 100 women with a mean age at second MRI of 50.5 years (23 to 83). Modic changes were classified as not present and types 1 to 3. Changes in Modic types over time and relationships between Modic changes and progression of degeneration of the disc or clinical symptoms were evaluated. A total of 31 subjects (13.9%) showed Modic changes at follow-up: type 1 in nine, type 2 in 18, type 3 in two, and types 1 and 2 in two. Modic changes at follow-up were significantly associated with numbness or pain in the arm, but not with neck pain or shoulder stiffness. Age (≥ 40 years), gender (male), and pre-existing disc degeneration were significantly associated with newly developed Modic changes. In the cervical spine over a ten-year period, type 2 Modic changes developed most frequently. Newly developed Modic changes were significantly associated with age, gender, and pre-existing disc degeneration

Introduction. Missile injuries are very serious injuries particularly in the cervical region. They are classified into high and low missile injuries when it involves the cervical spine. In modern guerrilla warfare, one must be aware of ballistic pathology with bullets as well as from explosives. In particular, improvised explosive devices commonly known as IED's play a new and important pathophysiology whether they are suicided vests or roadside bombs. They usually produce severe or lethal injuries and serious neurovascular deficit is frequent. We present the details of 40 patients with local experience on how to handle serious penetrating cervical missile injuries. Methods. All cases were collected from the record of Basrah University Hospital, Iraq. Healthy military gentlemen with ages ranging between 20–35 years were included. Results. 11 patients had bullet injuries and 29patients had fragments of shell injuries. The sites of injuries were 9: C2–C3, 12: C5–C6, 12: C4–C5 and 7: C7-T1. Bullet entrance was anterior in 23 patients, posterior in 7 patients and lateral in 10 patients. The cervical vertebrae were injured in 37 patients at body or lamina level while in 3 patients it was only neural tissue injuries. Missiles were retained in 13 patients. All injuries showed some degree of neurological deficit with quadriplegia in 26 patients. 9 patients presented with very serious injuries. No relation was found between the size of the missile and the extent of damage. Outcome of treatment in all patients was poor. Conclusion. Gunshot wounds only account for approximately one third of penetrating missile injuries in patients who survive and are well enough to receive medical treatment. 62% of patients' cohort were from explosive devices, consistent with data from 2010, where 58% of fatalities were from IED's occurring in foreign soldiers in Afghanistan. We discuss the importance of general supportive measures, generous wound excision, removal of the retained missiles and heavy cover of antibiotics

To compare the complication profile of a muscle splitting approach to the anterior cervical spine with previously described approaches. The authors describe and compare the complications of an approach that exposes the anterior cervical spine by directly splitting the strap muscles in the midline with blunt dissection thereby potentially reducing iatrogenic complications. A retrospective review of 62 operations to the anterior cervical spine, between 2002 and 2009. Indications: Fusion and arthroplasty procedures for brachalgia, axial neck pain and trauma. The postoperative complications. The complication rate was favourable compared to previously described approaches. The muscle splitting approach to the anterior cervical spine has a low complication rate compared to previously described approaches, and allows the cervical spine to be approached with blunt dissection thereby potentially minimising iatrogenic approach related complications

The effect of rheumatoid arthritis on the anatomy of the cervical spine has not been clearly documented. We studied 129 female patients, 90 with rheumatoid arthritis and 39 with other pathologies (the control group). There were 21 patients in the control group with a diagnosis of cervical spondylotic myelopathy, and 18 with ossification of the posterior longitudinal ligament. All had plain lateral radiographs taken of the cervical spine as well as a reconstructed CT scan. The axial diameter of the width of the pedicle, the thickness of the lateral mass, the height of the isthmus and internal height were measured. The transverse diameter of the transverse foramen (d1) and that of the spinal canal (d2) were measured, and the ratio d1/d2 calculated. The width of the pedicles and the thickness of the lateral masses were significantly less in patients with rheumatoid arthritis than in those with other pathologies. The area of the transverse foramina in patients with rheumatoid arthritis was significantly greater than that in the other patients. The ratio of d1 to d2 was not significantly different. A high-riding vertebral artery was noted in 33.9% of the patients with rheumatoid arthritis and in 7.7% of those with other pathologies. This difference was statistically significant. In the rheumatoid group there was a significant correlation between isthmus height and vertical subluxation and between internal height and vertical subluxation

Aims

Developmental cervical spinal stenosis (DcSS) is a well-known predisposing factor for degenerative cervical myelopathy (DCM) but there is a lack of consensus on its definition. This study aims to define DcSS based on MRI, and its multilevel characteristics, to assess the prevalence of DcSS in the general population, and to evaluate the presence of DcSS in the prediction of developing DCM.

Aims

The optimal procedure for the treatment of ossification of the posterior longitudinal ligament (OPLL) remains controversial. The aim of this study was to compare the outcome of anterior cervical ossified posterior longitudinal ligament en bloc resection (ACOE) with posterior laminectomy and fusion with bone graft and internal fixation (PTLF) for the surgical management of patients with this condition.

Aims

The aim of this study was to investigate whether the type of cervical disc herniation influences the severity of symptoms at the time of presentation, and the outcome after surgical treatment.

Seven men with a mean age of 63.9 years (59 to 67) developed dysphagia because of oesophageal compression with ossification of the anterior longitudinal ligament (OALL) and radiculomyelopathy due to associated stenosis of the cervical spine. The diagnosis of OALL was made by plain lateral radiography and classified into three types; segmental, continuous and mixed. Five patients had associated OALL in the thoracic and lumbar spine without ossification of the ligamentum flavum. All underwent removal of the OALL and six had simultaneous decompression by removal of ossification of the posterior longitudinal ligament or a bony spur. All had improvement of their dysphagia. Because symptomatic OALL may be associated with spinal stenosis, precise neurological examination is critical. A simultaneous microsurgical operation for patients with OALL and spinal stenosis gives good results without serious complications

Introduction. Research has suggested baby wearing results in happier healthier babies [1]. Various designs of carrier are available, is there one which has less impact on the biomechanics of the cervical spine?. Methods. 18 volunteers (9 male and female) performed a warm up procedure on the neck (movement through each range of motion), repeated thrice. Measurement of the active cervical range of motion (ACROM) in flexion and extension using a Cervical Range of Motion device, described in previous studies [2]. Volunteers were then allocated a baby carrier to wear including a specially designed “baby” mannequin (dimensions based on population average statistics for a 1yro). Volunteers continued with ADLs, returning after 2 hours. With the carrier removed, measurements were repeated (without warm-up). Volunteers were assessed at the same time of day, thrice (control, single carrier, double carrier) with at least 1 day between carrying. Results. ACROM measurements following the use of either single or double shoulder carrier, or no carrier showed through a paired t-test significance of <0.02, found a change from post-stretching to post-carrying in those wearing the single shoulder carrier, this was the only test period to result in a decrease in both extension and total ACROM for flexion-extension. Conclusions. Carrying an average 1 yro using a single shoulder carrier can lead to accelerated rate of change in extension of ACROM. These results may have an implication to healthy bodies, thus highly likely that choice of carrier in those with extant cervical spine dysfunction might lead to exacerbation of the problems and pain. Conflicts of interest: No conflicts of interest. Sources of funding: No funding obtained

We investigated the incidence of anomalies in the vertebral arteries and Circle of Willis with three-dimensional CT angiography in 55 consecutive patients who had undergone an instrumented posterior fusion of the cervical spine. We recorded any peri-operative and post-operative complications. The frequency of congenital anomalies was 30.9%, abnormal vertebral artery blood flow was 58.2% and vertebral artery dominance 40%. . The posterior communicating artery was occluded on one side in 41.8% of patients and bilaterally in 38.2%. Variations in the vertebral arteries and Circle of Willis were not significantly related to the presence or absence of posterior communicating arteries. Importantly, 18.2% of patients showed characteristic variations in the Circle of Willis with unilateral vertebral artery stenosis or a dominant vertebral artery, indicating that injury may cause lethal complications. One patient had post-operative cerebellar symptoms due to intra-operative injury of the vertebral artery, and one underwent a different surgical procedure because of insufficient collateral circulation. . Pre-operative assessment of the vertebral arteries and Circle of Willis is essential if a posterior spinal fusion with instrumentation is to be carried out safely. Cite this article: Bone Joint J 2014;96-B:535–40

Wrong-level surgery is a unique pitfall in spinal surgery and is part of the wider field of wrong-site surgery. Wrong-site surgery affects both patients and surgeons and has received much media attention. We performed this systematic review to determine the incidence and prevalence of wrong-level procedures in spinal surgery and to identify effective prevention strategies. We retrieved 12 studies reporting the incidence or prevalence of wrong-site surgery and that provided information about prevention strategies. Of these, ten studies were performed on patients undergoing lumbar spine surgery and two on patients undergoing lumbar, thoracic or cervical spine procedures. A higher frequency of wrong-level surgery in lumbar procedures than in cervical procedures was found. Only one study assessed preventative strategies for wrong-site surgery, demonstrating that current site-verification protocols did not prevent about one-third of the cases. The current literature does not provide a definitive estimate of the occurrence of wrong-site spinal surgery, and there is no published evidence to support the effectiveness of site-verification protocols. Further prevention strategies need to be developed to reduce the risk of wrong-site surgery

Fifteen patients with ankylosing spondylitis who had developed a severe flexion deformity of the cervical spine which restricted their field of vision to their feet, were treated by an extension osteotomy at the C7/T1 level. The operation was performed under general anaesthesia with the patient in the prone position and wearing a halo-jacket. Three had internal fixation using a Luque rectangle and wiring. Their mean age was 48 years. Before operation the mean cervical kyphosis was 23°; this was corrected to a mean of 31° of lordosis, a mean correction of 54°. All the patients were able to see straight ahead. One patient with normal neurology soon after operation became quadraparetic after one week; two others had unilateral palsy of the C8 root, which improved. There was subluxation at the site of osteotomy in four patients, and two of them developed a pseudarthrosis which required an anterior fusion

We have reviewed the cervical spine radiographs of 180 patients with athetoid cerebral palsy and compared them with those of 417 control subjects. Disc degeneration occurred earlier and progressed more rapidly in the patients, with advanced disc degeneration in 51%, eight times the frequency in normal subjects. At the C3/4 and C4/5 levels, there was listhetic instability in 17% and 27% of the patients, respectively, again six and eight times more frequently than in the control subjects. Angular instability was seen, particularly at the C3/4, C4/5 and C5/6 levels. We found a significantly higher incidence of narrowing of the cervical canal in the patients, notably at the C4 and C5 levels, where the average was 14.4 mm in the patients and 16.4 mm in normal subjects. The combination of disc degeneration and listhetic instability with a narrow canal predisposes these patients to relatively rapid progression to a devastating neurological deficit

Purpose. Patients with ankylosing spondylitis (AS) are vulnerable to cervical spine injury following relatively minor trauma. The authors present a retrospective review to determine the characteristics, treatment and outcome following cervical spine injury in these patients. Methods. Retrospective analysis of case notes and images of patients with AS admitted to the Spinal Injury Unit over a 10-year period. Results. Thirty-nine patients were identified. Records were available for 31 patients at the time of this analysis. The median age was 62 years (range 37-84). The male:female ratio was 7:1. Mechanisms of injury included falls (72%) and RTAs (7%), while 14% were unable to recall an injury. Alcohol was involved in 20% of the cases. Fracture through an ankylosed disc in the mid to low cervical spine was the commonest injury. Concomitant non-contiguous bony injury was seen in 2 patients. More than half (55%) were Grade E on ASIA impairment scale (AIS), while 14% were Grade A and 31% Grade D. Two patients required skull traction. Most patients were successfully treated by external immobilisation. Halo crown and jacket was the most common orthosis used. Twelve patients underwent surgical stabilisation. The mean duration of external immobilisation in the non-surgical group was 13 weeks (range 10-32), whereas following surgery it was 6 weeks (range 2-8). Adequate radiological evidence of fusion was seen in all 22 patients for whom this information was available at a median of 22 weeks (range 12-32). Patients with AIS Grade A and E were unchanged at discharge, while 4 patients in AIS Grade D improved to E. Conclusion. External immobilisation with halo in an effective first-line therapy in achieving fusion and stability. Surgical stabilisation can be reserved as a second-line treatment

Purpose. Patients with ankylosing spondylitis (AS) are vulnerable to cervical spine injury following relatively minor trauma. The authors present a retrospective review to determine the characteristics, treatment and outcome following cervical spine injury in these patients. Methods. Retrospective analysis of case notes and images of patients with AS admitted to the Spinal Injury Unit over a 10-year period. Results. Thirty-nine patients were identified. Records were available for 31 patients at the time of this analysis. The median age was 62 years (range 37-84). The male:female ratio was 7:1. Mechanisms of injury included falls (72%) and RTAs (7%), while 14% were unable to recall an injury. Alcohol was involved in 20% of the cases. Fracture through an ankylosed disc in the mid to low cervical spine was the commonest injury. Concomitant non-contiguous bony injury was seen in 2 patients. More than half (55%) were Grade E on ASIA impairment scale (AIS), while 14% were Grade A and 31% Grade D. Two patients required skull traction. Most patients were successfully treated by external immobilisation. Halo crown and jacket was the most common orthosis used. Twelve patients underwent surgical stabilisation. The mean duration of external immobilisation in the non-surgical group was 13 weeks (range 10-32), whereas following surgery it was 6 weeks (range 2-8). Adequate radiological evidence of fusion was seen in all 22 patients for whom this information was available at a median of 22 weeks (range 12-32). Patients with AIS Grade A and E were unchanged at discharge, while 4 patients in AIS Grade D improved to E. Conclusion. External immobilisation with halo in an effective first-line therapy in achieving fusion and stability. Surgical stabilisation can be reserved as a second-line treatment

Objective. To compare the effectiveness of the Aspen, Aspen Vista, Philadelphia, Miami-J and Miami-J Advanced collars at restricting cervical spine movement in the sagittal, coronal and axial planes. Methods. Nineteen healthy volunteers (12 female, 7 male) were recruited to the study. Collars were fitted by an approved physiotherapist. Eight ProReflex (Qualisys, Sweden) infra-red cameras were used to track the movement of retro reflective marker clusters placed in predetermined positions on the head and trunk. 3D kinematic data was collected during forward flexion, extension, lateral bending and axial rotation from uncollared and collared subjects. The physiological range of motion in the three planes was analysed using the Qualisys Track Manager system. Results. The Aspen and Philadelphia collars were found to be significantly more effective at restricting movement in the sagittal plane compared to the Vista (p<0.001), Miami-J (p<0.001 and p<0.01) and Miami-J Advanced (p<0.01 and p<0.05) collars. The Aspen collar was significantly more effective at restricting axial rotation than the Vista (p<0.001) and the Miami-J (p<0.05) collars. The Aspen, Philadelphia, Miami-J and Miami-J Advanced collars were comparable at restricting lateral bending but the Vista was significantly less effective than all the collars at restricting movement in this plane. Conclusion. The Aspen collar was found to be superior to the other collars when measuring restriction of movement of the cervical spine in all planes, particularly the sagittal and transverse planes, while the Aspen Vista was the least effective collar

The ratio of the sagittal diameter of the cervical canal to the corresponding diameter of the vertebral body has been described as a reliable means for assessing stenosis of the canal and detecting those at risk of cervical neuropraxia. The use of ratio techniques has the advantage of avoiding variation in magnification when direct measurements are made from plain radiographs. We examined the reliability of this method using plain lateral radiographs of unknown magnification and CT scans. We also assessed other possible ratios of anatomical measurements as a guide to the diameter of the canal. Our findings showed a poor correlation between the true diameter of the canal and the ratio of its sagittal diameter to that of the vertebral body. No other more reliable ratio was identified. The variability in anatomical morphology means that the use of ratios from anatomical measurements within the cervical spine is not reliable in determining the true diameter of the cervical canal

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

Objectives. A single degenerate intervertebral disc is suggested to promote rapid degeneration in its adjacent discs. We validated this hypothesis using discordant co-twin case-control design. Methods. 185 pairs of twins were selected from the TwinsUK database having cervical MRI scans at baseline and at follow-up, after 10 years. Isolated disc degeneration (IDD) was diagnosed in subjects having severe loss in disc height (graded 3/3) in a single disc, whilst discs immediately adjacent manifested little or no degeneration (graded 0 or 1). The controls' ‘adjacent discs’ were considered at the same levels as their affected co-twins. Results. Eight twin pairs fulfilled case/control criteria. At follow-up, no significant difference in adjacent disc degeneration between IDD cases and controls remained (p=0.69). Conclusions. Using a highly matched case-control design we did not find evidence that lone IDD has an adverse effect on the natural rate of adjacent disc degeneration in the cervical spine. No conflicts of interest. Acknowledgements. This study was supported by a grant from Globus Inc. Arthritis Research UK supported the imaging costs. TwinsUK. The study was funded by the Wellcome Trust; European Community's Seventh Framework Programme (FP7/2007–2013). The study also receives support from the National Institute for Health Research (NIHR)- funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust in partnership with King's College London