Aims

To determine the normal values and usefulness of the C1/4 space available for spinal cord (SAC) ratio and C1 inclination angle, which are new radiological parameters for assessing atlantoaxial instability in children with Down syndrome.

We reviewed the outcome of a retrospective case series of eight patients with atlantoaxial instability who had been treated by percutaneous anterior transarticular screw fixation and grafting under image-intensifier guidance between December 2005 and June 2008. The mean follow-up was 19 months (8 to 27). All eight patients had a solid C1–2 fusion. There were no breakages or displacement of screws. All the patients with pre-operative neck pain had immediate relief from their symptoms or considerable improvement. There were no major complications. Our preliminary clinical results suggest that percutaneous anterior transarticulation screw fixation is technically feasible, safe, useful and minimally invasive when using the appropriate instruments allied to intra-operative image intensification, and by selecting the correct puncture point, angle and depth of insertion

Objective: To review the clinical outcome of 37 consecutive patients undergoing C1– C2 transarticular fixation for patients with Rheumatoid Arthritis. Design: Prospective Observational Study. Methods: There were 37 patients at 2 centres. Age range was 37– 82 years. The time since diagnosis to treatment was 2– 23 years. Clinical presentation included suboccipital pain in 26/ 37 patients and neck pain in 29/37 patients. 22 patients had presented with myelopathy ( Ranawat grade II or III A). The preoperative imaging included Plain X Rays, CT scans and MRI scans. All patients underwent C1/ C2 transarticular screws ( Stealth guided) except 4 patients in which an aberrant course of the vertebral artery was identified. Outcome measures: Functional outcome, Complications, Postoperative Neurological Status, Neck Disability index, Myelopathy disability index. Results: 1 patient had died at 12 month followup. Neck pain improved in 22( 75%) of patients by > 5 points on the VAS. Suboccipital pain had improved in all patients. 17 patients (80%) improved following operation on the Ranawat Grading, 2 patient were worse and 3 patients remained the same. > 70% patients reported improvement in neck disability index and > 50% patients reported improvement in myelopathy disability index. Conclusions: C1/ C2 Transarticular fixation with spinal navigation is a safe technique for treating atlantoaxial instability in patients with Rheumatoid Arthritis. This study demonstrates improvement in all domains including neck disability, myelopathy scores and functional outcome

Introduction We review our experience with the use of plate and screw (C1 lateral mass and C2 pedicle) method of fixation in the treatment of 300 patients with disorders of the craniovertebral junction during a 17-year period at our center. We previously described this method of fixation in 1994. Methods Between 1988 and 2004, 250 patients with atlantoaxial instability were treated with the use of a plate and screw method of fixation at our institution. The various aetiologies of atlantoaxial instability were congenital, trauma and rheumatoid arthritis. All patients had mobile, completely reducible atlantoaxial subluxation. The male: female ratio was 3:1. C1 lateral mass screw and C2 pedicle screw were anchored to a plate bilaterally. For 3 months postoperatively, a hard cervical collar was used. The mean follow-up period was 42 months (range, 4 mo–17 yr). Recently, we have modified the technique by distracting the lateral facet joints, placing a cage bilaterally and then performing the lateral mass fixation for a subgroup of 50 patients with either fixed atlantoaxial joint subluxation or basilar invagination. Results Three patients died in the postoperative phase. Successful stabilization of the atlantoaxial region was documented with dynamic radiography in the other patients. In one patient, one screw was found to be broken 18 months after surgery; however, firm bony fusion was documented in this patient. There were no neurological, vascular, or infective complications. Discussion Segmental fixation of lateral masses with plate and screw method of fixation with the use of intra-articular bone grafts in patients with atlantoaxial instability yielded a 100% fusion rate with a low incidence of complications. Direct application of screws into the thick and large cortico-cancellous lateral masses of atlas and axis provides a biomechanically strong fixation of the region

Transarticular screw fixation with autograft is an established procedure for the surgical treatment of atlantoaxial instability. Removal of the posterior arch of C1 may affect the rate of fusion. This study assessed the rate of atlantoaxial fusion using transarticular screws with or without removal of the posterior arch of C1. We reviewed 30 consecutive patients who underwent atlantoaxial fusion with a minimum follow-up of two years. In 25 patients (group A) the posterior arch of C1 was not excised (group A) and in five it was (group B). Fusion was assessed on static and dynamic radiographs. In selected patients CT imaging was also used to assess fusion and the position of the screws. There were 15 men and 15 women with a mean age of 51.2 years (23 to 77) and a mean follow-up of 7.7 years (2 to 11.6). Stable union with a solid fusion or a stable fibrous union was achieved in 29 patients (97%). In Group A, 20 patients (80%) achieved a solid fusion, four (16%) a stable fibrous union and one (4%) a nonunion. In Group B, stable union was achieved in all patients, three having a solid fusion and two a stable fibrous union. There was no statistically significant difference between the status of fusion in the two groups. Complications were noted in 12 patients (40%); these were mainly related to the screws, and included malpositioning and breakage. The presence of an intact or removed posterior arch of C1 did not affect the rate of fusion in patients with atlantoaxial instability undergoing C1/C2 fusion using transarticular screws and autograft. Cite this article: Bone Joint J 2013;95-B:972–6

Introduction Rheumatoid arthritis also affects the spine and creates conditions that need surgical treatment. As in other parts of the body, the maintenance of function and reduction of pain are primary goals of surgical treatment, however the additional threat to the neurological structures create an additional dimension in the surgical treatment of the spine. Destructive processes of osteoligamentous structures and severe osteoporosis may be blamed as the principle cause for pain, deformity and subsequent neurological deficit in the rheumatoid patient’s spine. Cervical spine Atlantoaxial instability is the most frequently encountered pathology in the cervical spine of the rheumatoid patient. In order to avoid late appearance of myelopathy, the timing of surgery in the presence of significant atlantoaxial instability (ADD < 5mm) has to be carefully evaluated. The tendency is towards early surgical stabilization since no spontaneous improvement is to be expected in cases with aggressive rheumatoid arthritis. Late surgery not only carries the risk of causing myelopathy by repeated micro-trauma of the myelon, but also the need for extensive surgery including the occiput and the lower cervical spine in case of advanced destructive processes. The subaxial cervical spine has a tendency to disintegrate in the presence of aggressive course of rheumatoid arthritis. The extent of instability and site of compression has to be carefully analyzed, using MRI and neurophysiological examinations. Due to weak bone structures anterior and posterior interventions are often necessary. Lumbar spine The rheumatoid pathology in the lumbar spine is mainly influenced by the degree of osteoporosis. Typical osteoporotic fractures, often on several levels, represent the most frequent pathology, which needs surgical help. In case of persistent pain the relatively new technique of vertebroplasty offers an elegant way to reduce pain. If severe deformities occur, the osteoporotic structure of bone limits the surgical possibility of correction of the deformity. Conclusion “Wait and see”-policy in rheumatoid patients with spinal pathology is often not appropriate (as in other joints of the body) if function and neurology should be preserved and maintained. Early surgery represents usually minor intervention and is better tolerated than extensive corrections. Osteoporosis is the main limitation for surgical treatment in the rheumatoid spine

Introduction: The efficacy and complications of the transarticular screw procedure have been reported by many authors. However, few have reported this procedure for child younger than 10 years old. We have treated two children for atlantoaxial subluxation with transarticular screws, using a soft collar without a halo-vest, and have achieved bone union in good reduced position. Methods/results. Case 1: a 5-year-old boy with mental retardation and cerebellar infarction due to an insufficiency of the vertebral artery resulting in severe atlantoaxial instability. He presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum. He has been treated with transarticular screw and iliac bone graft by Brooks procedure. Case 2: an 8-year-old boy with congenital spondyloepiphyseal dysplasia and a right valgus knee. He, too, presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum, and has been treated with transarticular screw and iliac bone graft by Brooks procedure. In both cases, we used two half-thread cortical screws with a diameter of 2.7mm and a length of 30mm for the transarticular screw procedure. Discussion/conclusion: Rigid external fixation was obtained by Halo-vest. This method, however, would be expected to cause mental stress for the child patient and the family. More rigid internal fixation would be required to resolve this problem. More rigid internal fixation can be obtained with the transarticular screw, and postoperative orthosis can be performed easily, without the need for a Halo-vest

Purpose. In stabilisations of atlantoaxial instabilities it holds risks to injure the A. vertebralis as well as neurological structures. Furthermore the posterior approach of the upper part of the cervical spine requires a huge and traumatic preparation of the soft tissue. However the anterior transarticular C1-2 fusion (ATF) is less traumatic and offers almost the same strengh of the stabilisation. Methods. Since the 01/2007 22 multimorbid patients with atlanto-axial instabilities of different entities were treated via the ATF, were regular examined radiologicaly (x-ray/CT) and the procedure critically judged. Results. C1-2 fusions were performed in 22 patients (17f, 5m, Ø 81,67 years). Main symptoms was pain radiating in the upper cervical spine and the occiput, 2 Patients complaining radiating pain with paraesthesia. The average operation-time took 64,5 min. Leftside the screws of Ø 39,5mm (32–44mm), rightside of 36mm (32–44mm) were inserted in addiction to the point of access and the angle of insertion (mediolateral angle Ø 32,0°, ventrodorsal Ø17,6°). No introperative complications occured, one revision had to be done because of p.o. bleeding, one because of screw dislocation. Postoperative x-ray and CT control of the upper cervical spine showed 30/44 screws in 22 patients in correct position. 8 (18,2%) screws were too long, 3 (6,8%) screws were placed too anterior and 3 (6,8%) too medial. 8 additional positionated dens-screws were in correct position. After a clear learning curve both screws of the 6th patient were positoinated correct. Two aspects are important for success: Correct entry point and right insertion of the angle in the coronar and sagittal view. A low intraoperative blood loss, a non traumatic access as well as an immediate pain decrease have to be valued positively for this procedure. Conclusions. The gentle procedure of the ATF requires-despite of the huge experience in anterior surgery of dens fractures - a learning curve, because of the more proximate insertion point, the flat insertion angle and the closeness of the A. vertebralis. If these aspects are going to be noticed, failed screw positioning and excessive length as well as injuries of the A. vertebralis can be avoided

Purpose: Ligament laxity is a common feature of trisomy 21 and is incriminated in most of the orthopaedic disorders observed. Early diagnosis and management is essential. C1-C2 instability is a recognised manifestation in trisomy 21 and is associated, at least theoretically, with significant risk of cord complications. The purpose of this work was to provide a descriptive analysis of the C1-C2 joint in trisomy 21 and to analyse instability factors in order to determine the tolerable C1-C2 distance. Material and methods: Within the framework of a French national epidemiology survey of trisomy 21, we focused on the C1-C2 joint. A total of 472 children with trisomy 21 were identified; 458 who were examined were included in this study. Careful history taking and a detailed physical examination with neurological tests (search for even minimal signs of neurological disorders) was conducted. The Carter and Wilkinson method was used to assess joint laxity. The same specialist searched for other orthopaedic disorders. Patients were divided into two groups depending on the presence or absence of neurological signs. Two groups were also distinguished according to the presence or absence of generalised laxity (Carter and Wilkinson). Lateral x-rays centred on C1-C2 were performed by the same technician on the same machine with the patient in a neutral position, hyperflexion and hyperextension. The same technique inspired by the method described by Singer et al. and modified for simplification was used in all cases. The same observer interpreted the images using a single-blinded protocol to search for congenital malformations and signs of degeneration, measure the C1-C2 distance the minimal sagittal diameter and the C1-C2 angle (not reported in the literature and described for this study). These measures were then compared with data in the literature as available and correlated by age, gender, presence of neurological signs and joint laxity. Seven patients were excluded from the study due to insufficient cooperation for the x-rays and nine because of incomplete clinical or radiological data. The statistical analysis was performed on data from 442 patients. Quantitative variables were compared with the Pearson test and parameteric ANOVA was used to search for correlations of quantitative and qualitative variables. Significance was set at p< 0.05. Results: Mean patient age was 13.8 years. There were 184 girls and 258 boys. Minor neurological anomalies were found in 42% of the patients. There were no cases of major motor deficit. Generalised laxity as defined by Carter and Wilkinson was observed in 24% of patients. Other orthopaedic problems, basically of the foot, were found in 85%. The radiograms revealed a very wide range of measures were thus expressed as means. The C1-C2 distance was greater than 4 mm in 34 patients on the flexion films (limit established in the literature for instability in trisomy 21). The maximal C1-C2 distance in the neutral position was 8 mm, 9.6 mm in flexion. The lowest minimal sagittal distance was 8 mm in flexion and 10 mm in the neutral position (the lower limit reported in the literature before considering the cord to be threatened in 14 mm). The greatest variability was found for the C1-C2 angle. Ligament laxity and atlantoaxial distance were inversely proportional to patient age, but there was no significant correlation between atlantoaxial instability (C1-C2 distance > 4 mm) and gender or generalised hyperlaxity. There was no significant correlation between C1-C2 instability or laxity and neurological signs. Discussion and conclusion: Compared with earlier publications, our series offers the advantage of a large unselected population providing epidemiological data on trisomy 21. A standard radiography protocol was used. The large majority of the radiographic measures reported in the literature do not take into account the magnification effect nor position variability between patients. Our findings confirm certain data in the literature and also provide new information suggesting it could be useful to revisit certain pathogenic hypotheses about C1-C2 instability and its neurological consequences in trisomy 21. Two important observations were the absence of a correlation between general laxity and C1-C2 instability and the absence of correlation between C1-C2 instability and the presence of neurological signs

Structural defects of the posterior arch of the atlas are rare, and range from clefts of variable location and size to more extensive defects such as complete agenesis. These abnormalities are usually incidental radiological findings. We present a case of a fracture of the anterior arch of the atlas associated with a congenital abnormality of the posterior arch.

Aims

Although atlantoaxial rotatory fixation (AARF) is a common cause of torticollis in children, the diagnosis may be delayed. The condition is characterised by a lack of rotation at the atlantoaxial joint which becomes fixed in a rotated and subluxed position. The management of children with a delayed presentation of this condition is controversial. This is a retrospective study of a group of such children.

Patients with skeletal dysplasia are prone to developing advanced osteoarthritis of the knee requiring total knee replacement (TKR) at a younger age than the general population. TKR in this unique group of patients is a technically demanding procedure owing to the deformity, flexion contracture, generalised hypotonia and ligamentous laxity. We retrospectively reviewed the outcome of 11 TKRs performed in eight patients with skeletal dysplasia at our institution using the Stanmore Modular Individualised Lower Extremity System (SMILES) custom-made rotating-hinge TKR. There were three men and five women with mean age of 57 years (41 to 79). Patients were followed clinically and radiologically for a mean of seven years (3 to 11.5). The mean Knee Society clinical and function scores improved from 24 (14 to 36) and 20 (5 to 40) pre-operatively, respectively, to 68 (28 to 80) and 50 (22 to 74), respectively, at final follow-up. Four complications were recorded, including a patellar fracture following a fall, a tibial peri-prosthetic fracture, persistent anterior knee pain, and aseptic loosening of a femoral component requiring revision. Our results demonstrate that custom primary rotating-hinge TKR in patients with skeletal dysplasia is effective at relieving pain, with a satisfactory range of movement and improved function. It compensates for bony deformity and ligament deficiency and reduces the likelihood of corrective osteotomy. Patellofemoral joint complications are frequent and functional outcome is worse than with primary TKR in the general population.

The Morquio syndrome is a rare disorder which presents with a number of musculoskeletal problems. The literature describing total knee replacement in these patients is sparse. We describe the management of a patient with bilateral instability and pain in the knees using bilateral constrained knee replacements, and followed up for five years with pre- and postoperative knee scores. We highlight the difficulties encountered and discuss the end results.

The management of joint replacement in lysosomal storage diseases has not been well reported. We present three patients with progressive degenerative changes of the hips who required bilateral total hip replacement in early childhood. The stature of the patients make it essential to have access to appropriately scaled prostheses. Consideration has to be given to associated disorders of the skeleton which must be carefully screened to ensure safety in providing appropriate anaesthesia as well as ensuring that there is no cardiac abnormality. In one patient, a periprosthetic fracture was sustained in one hip in the early post-operative course requiring internal fixation.

The patient made a full recovery and all six hips were clinically and radiologically satisfactory at mid-term review.

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.

Traumatic atlanto-occipital dislocation in adults is usually fatal and survival without neurological deficit is rare. The surgical management of those who do survive is difficult and controversial. Most authorities recommend posterior occipitoaxial fusion, but this compromises cervical rotation. We describe a case in which a patient with a traumatic atlanto-occipital disruption but no neurological deficit was treated by atlanto-occipital fusion using a new technique consisting of cancellous bone autografting supported by an occipital plate linked by rods to lateral mass screws in the atlas. The technique is described in detail. At one year the neck was stable, radiological fusion had been achieved, and atlantoaxial rotation preserved.

The rationale behind this approach is discussed and the relevant literature reviewed. We recommend the technique for injuries of this type.

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.