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.

A review of the current literature shows that there is a lack of consensus regarding the treatment of spondylolysis and spondylolisthesis in children and adolescents. Most of the views and recommendations provided in various reports are weakly supported by evidence. There is a limited amount of information about the natural history of the condition, making it difficult to compare the effectiveness of various conservative and operative treatments. This systematic review summarises the current knowledge on spondylolysis and spondylolisthesis and attempts to present a rational approach to the evaluation and management of this condition in children and adolescents.

The October 2013 Spine Roundup³⁶⁰ looks at: Standing straighter may reduce falls; Operative management of congenital kyphosis; Athletic discectomy; Lumbar spine stenosis worsens with time; Flexible stabilisation?: spinal stenosis revisited; Do epidural steroids cause spinal fractures?; Who does well with cervical myelopathy?; Secretly adverse to BMP-2?

This review of the literature presents the current understanding of Scheuermann’s kyphosis and investigates the controversies concerning conservative and surgical treatment. There is considerable debate regarding the pathogenesis, natural history and treatment of this condition. A benign prognosis with settling of symptoms and stabilisation of the deformity at skeletal maturity is expected in most patients. Observation and programmes of exercise are appropriate for mild, flexible, non-progressive deformities. Bracing is indicated for a moderate deformity which spans several levels and retains flexibility in motivated patients who have significant remaining spinal growth.

The loss of some correction after the completion of bracing with recurrent anterior vertebral wedging has been reported in approximately one-third of patients. Surgical correction with instrumented spinal fusion is indicated for a severe kyphosis which carries a risk of progression beyond the end of growth causing cosmetic deformity, back pain and neurological complications. There is no consensus on the effectiveness of different techniques and types of instrumentation. Techniques include posterior-only and combined anteroposterior spinal fusion with or without posterior osteotomies across the apex of the deformity. Current instrumented techniques include hybrid and all-pedicle screw constructs.

We report five children who presented at the mean age of 1.5 years (1.1 to 1.9) with a progressive thoracolumbar kyphosis associated with segmental instability and subluxation of the spine at the level above an anteriorly-wedged hypoplastic vertebra at L1 or L2. The spinal deformity appeared to be developmental and not congenital in origin. The anterior wedging of the vertebra may have been secondary to localised segmental instability and subsequent kyphotic deformity.

We suggest the term ‘infantile developmental thoracolumbar kyphosis with segmental subluxation of the spine’ to differentiate this type of deformity from congenital displacement of the spine in which the congenital vertebral anomaly does not resolve. Infantile developmental kyphosis with segmental subluxation of the spine, if progressive, may carry the risk of neurological compromise. In all of our patients the kyphotic deformity progressed over a period of three months and all were treated by localised posterior spinal fusion. At a mean follow-up of 6.6 years (5.0 to 9.0), gradual correction of the kyphosis was seen on serial radiographs as well as reconstitution of the hypoplastic wedged vertebra to normality. Exploration of the arthrodesis was necessary at nine months in one patient who developed a pseudarthrosis.

Our aim was to review the efficacy of the wound vacuum-assisted closure (VAC) system in the treatment of deep infection after extensive instrumentation and fusion for spinal deformity in children and adolescents.

A total of 14 patients with early deep spinal infection were treated using this technique. Of these, 12 had neuromuscular or syndromic problems. Clinical and laboratory data were reviewed. The mean follow-up was 44 months (24 to 72). All wounds healed. Two patients required plastic surgery to speed up the process. In no patient was the hardware removed and there was no loss of correction or recurrent infection.

We believe that the wound VAC system is a useful tool in the armamentarium of the spinal surgeon dealing with patients susceptible to wound infections, especially those with neuromuscular diseases. It allows for the retention of the instrumentation and the maintenance of spinal correction. It is reliable and easy to use.

The June 2012 Spine Roundup³⁶⁰ looks at: back pain; spinal fusion for tuberculosis; anatomical course of the recurrent laryngeal nerve; groin pain with normal imaging; the herniated intervertebral disc; obesity’s effect on the spine; the medicolegal risks of cauda equina syndrome; and intravenous lidocaine use and failed back surgery syndrome.

We present the case of a 15-year-old boy with symptoms due to Klippel–Feil syndrome. Radiographs and CT scans demonstrated basilar impression, occipitalisation of C1 and fusion of C2/C3. MRI showed ventral compression of the medullocervical junction. Skull traction was undertaken pre-operatively to determine whether the basilar impression could be safely reduced. During traction, the C3/C4 junction migrated 12 mm caudally and spasticity resolved. Peri-operative skull-femoral traction enabled posterior occipitocervical fixation without decompression. Following surgery, cervical alignment was restored and spasticity remained absent. One year after surgery he was not limited in his activities. The surgical strategy for patients with basilar impression and congenital anomalies remains controversial. The anterior approach with decompression is often recommended for patients with ventral compression of the medullocervical region, but such procedures are technically demanding and carry a significant risk of complications. Our surgical strategy was an alternative solution. Prior to a posterior cervical fixation, without decompression, skull traction was used to confirm that the deformity was reducible and effective in resolving associated myelopathy.

We reviewed 31 consecutive patients with Friedreich’s ataxia and scoliosis. There were 24 males and seven females with a mean age at presentation of 15.5 years (8.6 to 30.8) and a mean curve of 51° (13° to 140°). A total of 12 patients had thoracic curvatures, 11 had thoracolumbar and eight had double thoracic/lumbar. Two patients had long thoracolumbar collapsing scoliosis with pelvic obliquity and four had hyperkyphosis. Left-sided thoracic curves in nine patients (45%) and increased thoracic kyphosis differentiated these deformities from adolescent idiopathic scoliosis. There were 17 patients who underwent a posterior instrumented spinal fusion at mean age of 13.35 years, which achieved and maintained good correction of the deformity. Post-operative complications included one death due to cardiorespiratory failure, one revision to address nonunion and four patients with proximal junctional kyphosis who did not need extension of the fusion. There were no neurological complications and no wound infections. The rate of progression of the scoliosis in children kept under simple observation and those treated with bracing was less for lumbar curves during bracing and similar for thoracic curves. The scoliosis progressed in seven of nine children initially treated with a brace who later required surgery. Two patients presented after skeletal maturity with balanced curves not requiring correction. Three patients with severe deformities who would benefit from corrective surgery had significant cardiac co-morbidities.

We evaluated the use of surgical stabilisation for atlantoaxial subluxation after a follow-up of 24 years in 50 rheumatoid patients who had some degree of pain but no major neurological deficit.

The mortality of patients treated by atlantoaxial fusion was significantly lower than for those who received conservative treatment. The deaths resulted from infection or comorbid conditions. The significantly high relative risks of mortality from conservative treatment compared with surgical treatment were mutilating disease and susceptible factors on both of the HLA-DRB1 alleles. Relief from pain and neurological and functional recovery were better, and the radiological degree of atlantoaxial translocation was less in those who were surgically treated compared with those who were not. Two patients had superficial local infections after surgery. We conclude that prophylactic atlantoaxial fusion is better than conservative treatment in these patients.

Our aim in this prospective radiological study was to determine whether the flexibility rate calculated from radiographs obtained during forced traction under general anaesthesia, was better than that of fulcrum-bending radiographs before corrective surgery in predicting the extent of the available correction in patients with idiopathic scoliosis. We evaluated 33 patients with a Cobb angle > 60° on a standing posteroanterior radiograph, who had been treated by posterior correction. Pre-operative standing fulcrum-bending radiographs and those with forced-traction under general anaesthesia were obtained. Post-operative standing radiographs were taken after surgical correction.

The mean forced-traction flexibility rate was 55% (sd 11.3) which was significantly higher than the mean fulcrum-bending flexibility rate of 32% (sd 16.1) (p < 0.001). We found no correlation between either the forced-traction or fulcrum-bending flexibility rates and the correction rate post-operatively (p = 0.24 and p = 0.44, respectively).

Radiographs obtained during forced traction under general anaesthesia were better at predicting the flexibility of the curve than fulcrum-bending radiographs in curves with a Cobb angle > 60° in the standing position and may identify those patients for whom supplementary anterior surgery can be avoided.

There are many causes of paraspinal muscle weakness which give rise to the dropped-head syndrome. In the upper cervical spine the central portion of the spinal cord innervates the cervical paraspinal muscles. Dropped-head syndrome resulting from injury to the central spinal cord at this level has not previously been described. We report two patients who were treated acutely for this condition. Both presented with weakness in the upper limbs and paraspinal cervical musculature after a fracture of C2. Despite improvement in the strength of the upper limbs, the paraspinal muscle weakness persisted in both patients. One ultimately underwent cervicothoracic fusion to treat her dropped-head syndrome.

While the cause of the dropped-head syndrome cannot be definitively ascribed to the injuries to the spinal cord, this pattern is consistent with the known patho-anatomical mechanisms of both injury to the central spinal cord and dropped-head syndrome.

Fractures of the odontoid in children with an open basilar synchondrosis differ from those which occur in older children and adults. We have reviewed the morphology of these fractures and present a classification system for them.

There were four distinct patterns of fracture (types IA to IC and type II) which were distinguished by the site of the fracture, the degree of displacement and the presence or absence of atlantoaxial dislocation. Children with a closed synchondrosis were classified using the system devised by Anderson and D’Alonzo. Those with an open synchondrosis had a comparatively lower incidence of traumatic brain injury, a higher rate of missed diagnosis and a shorter mean stay in hospital. Certain subtypes (type IA and type II) are likely to be missed on plain radiographs and therefore more advanced imaging is recommended. We suggest staged treatment with initial stabilisation in a Halo body jacket and early fusion for those with unstable injuries, severe displacement or neurological involvement.

We carried out a prospective study to determine whether the addition of a recombinant human bone morphogenetic protein (rhBMP-2) to a machined allograft spacer would improve the rate of intervertebral body fusion in the spine. We studied 77 patients who were to undergo an interbody fusion with allograft and instrumentation. The first 36 patients received allograft with adjuvant rhBMP-2 (allograft/rhBMP-2 group), and the next 41, allograft and demineralised bone matrix (allograft/demineralised bone matrix group). Each patient was assessed clinically and radiologically both pre-operatively and at each follow-up visit using standard methods. Follow-up continued for two years.

Every patient in the allograft/rhBMP-2 group had fused by six months. However, early graft lucency and significant (> 10%) subsidence were seen radiologically in 27 of 55 levels in this group. The mean graft height subsidence was 27% (13% to 42%) for anterior lumbar interbody fusion, 24% (13% to 40%) for transforaminal lumbar interbody fusion, and 53% (40% to 58%) for anterior cervical discectomy and fusion. Those who had undergone fusion using allograft and demineralised bone matrix lost only a mean of 4.6% (0% to 15%) of their graft height.

Although a high rate of fusion (100%) was achieved with rhBMP-2, significant subsidence occurred in more than half of the levels (23 of 37) in the lumbar spine and 33% (6 of 18) in the cervical spine. A 98% fusion rate (62 of 63 levels) was achieved without rhBMP-2 and without the associated graft subsidence. Consequently, we no longer use rhBMP-2 with allograft in our practice if the allograft has to provide significant structural support.

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.

Fracture of a pedicle is a rare complication of spinal instrumentation using pedicular screws, but it can lead to instability and pain and may necessitate extension of the fusion. Osteosynthesis of the fractured pedicle by cerclage-wire fixation and augmentation of the screw fixation by vertebroplasty or temporary elongation of the fixation, allows stabilisation without sacrifice of the adjacent healthy segment. We describe three patients who developed a fracture of the pedicle in the most caudal instrumented vertebra early after lumbar spinal fusion.

During revision surgery the pedicles were reduced and secured by a soft cerclage wire bilaterally. Fusion was obtained at the site of the primary instrumentation and healing of the pedicles was achieved. Cerclage wiring of the fractured pedicle seems to be safe and avoids permanent extension of the fusion without the sacrifice of an otherwise healthy segment.

The April 2013 Spine Roundup³⁶⁰ looks at: smuggling spinal implants; local bone graft and PLIF; predicting disability with slipped discs; mortality and spinal surgery; spondyloarthropathy; brachytherapy; and fibrin mesh and BMP.