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

Three unusual injuries of the cervical spine in wearers of safety belts are reported. In each case, the presence of diagonal bruising and abrasions in the line of the sash strap indicated its involvement in the mechanism of the injury

1. Nineteen patients with classical rheumatoid arthritis complicated by severe subluxation of the cervical spine are reported. 2. Thirteen patients had atlanto-axial subluxation. This was the only level ofinvolvement in ten. 3. The next most frequent level to be involved was C.4-5. This occurred in five patients. 4. Eleven patients required surgery for symptoms or signs of spinal cord compression or vertebral artery insufficiency. 5. Operations included six posterior fusions, three anterior fusions and two laminectomies. 6. The differential diagnosis, the radiological findings, the indications for surgery and the results of treatment are discussed

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

We reviewed the magnetic resonance (MR) images of eight adults with acute hyperextension-dislocation of the cervical spine. The images were obtained to evaluate damage to the spinal cord. All eight patients had disruption of the anterior longitudinal ligament and of the annulus of the intervertebral disc, and separation of the posterior longitudinal ligament from the subjacent vertebra. Some, but not all, showed widening of the disc space, posterior bulging or herniation of the nucleus pulposus, and disruption of the ligamentum flavum. The MR demonstration of these ligament injuries, taken with the clinical and radiographic findings, establishes the mechanism of hyperextension-dislocation, confirms the diagnosis, and is relevant to management

Eight patients with neurofibromatosis presented with symptoms of cervical spine involvement over a period of 17 years, five of them within the second decade of life. The symptoms included neurological deficit in five, a neck mass in four, and deformity in three; only two complained of pain. Osteolysis of vertebral bodies with kyphosis of more than 90 degrees was the most common radiological feature. Posterior fusion failed in the one patient in whom it was performed. Good results were achieved by anterior fusion, alone, or combined with posterior fusion. Surgical complications included one death in a patient with a malignant neurofibroma, and one case of transient neurological deterioration

Eleven patients with metastases in the cervical spine had operations for severe pain due to a pathological fracture which, in eight of the cases, was unstable. Conservative treatment had either failed or was unsuitable. In the first five patients internal fixation with tension band wires and bone grafts was supported by a halo-brace. The method has evolved to the use of posterior instrumentation with laminar wires from two levels above the lesion to two levels below. Stability is increased by the use of bone cement with or without bone autografts applied to one side of the spine. This technique enables the patient to get up within a few days of operation--a great advantage when life expectancy is limited. The operations were successful in all except one case

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

We treated 36 patients with unilateral facet dislocations or fracture-dislocations of the cervical spine at the Mayo Clinic between 1975 and 1986. Adequate records were available for 34: ten patients were treated by open reduction and posterior fusion, and 24 by nonoperative management. Of these, 19 had halo traction followed by halo-thoracic immobilisation, four had a simple cervicothoracic orthosis, and one received no active treatment. Anatomical reduction was achieved more frequently in the operative group (60% compared with 25%). Nonoperative treatment was more likely to result in cervical translation on flexion/extension lateral radiographs, and in significant symptoms. Only 36% of the patients treated by halo traction achieved anatomical alignment; in 25% halo traction failed to achieve or maintain any degree of reduction. During halo-thoracic immobilisation, half of the patients lost some degree of reduction and patient satisfaction with the appliance was low. Open reduction and internal fixation of unilateral facet injuries gave better results. 6

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 report 13 patients with missed bilateral facet dislocation of the lower cervical spine who subsequently developed severe spinal-cord involvement. There were more women and the patients were older than in most groups with spinal injury. The commonest cause was a fall, and paralysis appeared from six to 48 hours after injury in most patients. Ten patients made some recovery after late reduction but three remained totally paralysed. We discuss the pathogenesis of the late cord lesion and the reasons for delay in diagnosis

The case is reported of an elderly man with asymptomatic cervical spondylosis who sustained a minor hyperextension injury of the cervical spine when the brakes of a car were applied suddenly to avoid a collision. Within six hours marked swelling of the neck and severe dyspnoea developed, and a lateral radiograph showed the pharyngeal shadow displaced far forwards and a crack fracture of an anterior osteophyte. Tracheostomy and evacuation of a massive prevertebral haematoma were performed, with immediate relief. The case draws attention to the possibility of this serious complication of a "whiplash" type of injury

The outcome of operations performed on 38 patients for rheumatoid disorders of the cervical spine were analysed 10 or more years later. The mean age of the patients at the time of operation was 56 years (35 to 77); 32 had seropositive disease. The mean duration of the disease was 17 years (four to 36). Twenty-seven patients had painful anterior atlanto-axial subluxation (AAS), nine had subaxial subluxation alone and two had severe cranial subluxation of the odontoid, one also with subaxial subluxation. One patient died from postoperative staphylococcal septicaemia and another 18 died during the follow-up period. Patients with coincident cardiac or other diseases, and those with cranial subluxation of the odontoid of more than 3 mm had an increased mortality. Neither the patients' age nor the magnitude of AAS correlated with mortality. Of the 37 patients with occipitocervical pain, 30 were relieved and all the six patients with tetraparesis were improved. Of the 24 Gallie fusions only 12 were solidly united; patients with long-term cortisone treatment were more likely to develop pseudarthrosis. There was no correlation between clinical outcome and radiological result. Four patients had further operations to treat subluxation which developed below the fused segments

We report and discuss a combined anterior, anterolateral and posterior approach to the lower cervical spine. This was used for the radical resection of a recurrent osteoblastoma which involved the lateral mass, pedicle, and lamina of the sixth cervical vertebra

We have reviewed 32 patients with rheumatoid disease of the cervical spine who underwent a total of 40 operations aimed at correcting instability and improving any associated neurovascular deficit. Apart from four patients with intractable pain, the main indication for surgery was progressive neurological impairment. Of the 32 primary operations, 19 (60%) were successful; the remainder failed to achieve their objective and there were two deaths in the immediate postoperative period. Of eight secondary operations performed for recurrence of symptoms or failure to relieve cervical myelopathy, only four were successful. Of nine operations for bony decompression to relieve cord compression from irreducible subluxation, only four were successful. The overall results show a success rate of 57% and a failure rate of 35% with early operative mortality in 8%. Indications for operation are discussed and earlier diagnosis is considered to be the key to improved results

This retrospective study assesses the complications affecting the cervical spine after halo-pelvic traction in 83 patients who were followed up for a minimum of five years. Forty-four patients (53 per cent) had significant cervical complications such as radiological degenerative changes, avascular necrosis of the dens, loss of movement, pain or spontaneous fusion. The most important predisposing factors were a long period in the halo-pelvic apparatus, tuberculous kyphosis, stiffness of the spinal deformity and an age of 15 years or more at the time of application

Forty patients with tuberculosis of the lower cervical spine (second to seventh cervical vertebrae) have been reviewed. Pain and stiffness were important and dominant symptoms. Two types of disease were recognised. In children under 10 years old involvement was extensive and diffuse with the formation of large abscesses. In patients over 10 the disease was localised and produced less pus, but was associated with a much higher incidence of Pott's paraplegia. The overall incidence of cord compression was 42.5 per cent (17 out of 40); 13 of the 16 patients with the "adult" type of disease had this complication. The commonest method of treatment was with antituberculous drugs, anterior excision of diseased bone and grafting. This regime rapidly relieved pain, compressive respiratory symptoms due to abscesses and Pott's paraplegia. It also corrected kyphotic deformities from an average of 25.5 degrees to 5.4 degrees

Instability may present at a different level after successful stabilisation of an unstable segment in apparently isolated injuries of the cervical spine. It can give rise to progressive deformity or symptoms which require further treatment. We performed one or more operations for unstable cervical spinal injuries on 121 patients over a period of 90 months. Of these, five were identified as having instability due to an initially unrecognised fracture-subluxation at a different level. We present the details of these five patients and discuss the problems associated with their diagnosis and treatment

Ossification of the posterior longitudinal ligament in the cervical region is generally regarded as a rare disease, though a Japanese series of 185 cases has been reported. The main symptoms arise from a myelopathy, the degree of which varies from moderate to severe, due to stenosis of the spinal canal. In order to clarify the relationship between the severity of symptoms and the cross-sectional area of ossification, axial transverse tomography of the cervical spine has been carried out on twenty-six patients at intervals of 5 millimetres over the full extent of the ossification. In this way the cross-sectional areas of the ossified tissue and of the spinal canal were calculated. The former varied from a minimum of 0.8 to a maximum of 1.8 square centimetres. In cases of severe myelopathy the ossification was mainly at the fourth and fifth cervical levels and the stenosis ration exceeded 30 per cent