Fractures of the odontoid peg are common spinal injuries in the elderly. This study compares the survivorship of a cohort of elderly patients with an isolated fracture of the odontoid peg versus that of patients who have sustained a fracture of the hip or wrist. A six-year retrospective analysis was performed on all patients aged > 65 years who were admitted to our spinal unit with an isolated fracture of the odontoid peg. A Kaplan–Meier table was used to analyse survivorship from the date of fracture, which was compared with the survivorship of similar age-matched cohorts of 702 consecutive patients with a fracture of the hip and 221 consecutive patients with a fracture of the wrist.

A total of 32 patients with an isolated odontoid fracture were identified. The rate of mortality was 37.5% (n = 12) at one year. The period of greatest mortality was within the first 12 weeks. Time made a lesser contribution from then to one year, and there was no impact of time on the rate of mortality thereafter. The rate of mortality at one year was 41.2% for male patients (7 of 17) compared with 33.3% for females (5 of 15).

The rate of mortality at one year was 32% (225 of 702) for patients with a fracture of the hip and 4% (9 of 221) for those with a fracture of the wrist. There was no statistically significant difference in the rate of mortality following a hip fracture and an odontoid peg fracture (p = 0.95). However, the survivorship of the wrist fracture group was much better than that of the odontoid peg fracture group (p < 0.001). Thus, a fracture of the odontoid peg in the elderly is not a benign injury and is associated with a high rate of mortality, especially in the first three months after the injury.

Cite this article: Bone Joint J 2014;96-B:88–93.

The purpose of this study was to devise a simple but reliable radiological method of identifying a lumbosacral transitional vertebra (LSTV) with a solid bony bridge on sagittal MRI, which could then be applied to a lateral radiograph.

The vertical mid-vertebral angle (VMVA) and the vertical anterior vertebral angle (VAVA) of the three most caudal segments of the lumbar spine were measured on MRI and/or on a lateral radiograph in 92 patients with a LSTV and 94 controls, and the differences per segment (Diff-VMVA and Diff-VAVA) were calculated. The Diff-VMVA of the two most caudal vertebrae was significantly higher in the control group (25° (sd 8) than in patients with a LSTV (type 2a+b: 16° (sd 9), type 3a+b: -9° (sd 10), type 4: -5° (sd 7); p < 0.001). A Diff-VMVA of ≤ +10° identified a LSTV with a solid bony bridge (type 3+4) with a sensitivity of 100% and a specificity of 89% on MRI and a sensitivity of 94% and a specificity of 74% on a lateral radiograph. A sensitivity of 100% could be achieved with a cut-off value of 28° for the Diff-VAVA, but with a lower specificity (76%) on MRI than with Diff-VMVA.

Using this simple method (Diff-VMVA ≤ +10°), solid bony bridging of the posterior elements of a LSTV, and therefore the first adjacent mobile segment, can be easily identified without the need for additional imaging.

Cite this article: Bone Joint J 2013;95-B:1533–7.

A combined anterior and posterior surgical approach is generally recommended in the treatment of severe congenital kyphosis, despite the fact that the anterior vascular supply of the spine and viscera are at risk during exposure. The aim of this study was to determine whether the surgical treatment of severe congenital thoracolumbar kyphosis through a single posterior approach is feasible, safe and effective.

We reviewed the records of ten patients with a mean age of 11.1 years (5.4 to 14.1) who underwent surgery either by pedicle subtraction osteotomy or by vertebral column resection with instrumented fusion through a single posterior approach.

The mean kyphotic deformity improved from 59.9° (45° to 110°) pre-operatively to 17.5° (3° to 40°) at a mean follow-up of 47.0 months (29 to 85). Spinal cord monitoring was used in all patients and there were no complications during surgery. These promising results indicate the possible advantages of the described technique over the established procedures. We believe that surgery should be performed in case of documented progression and before structural secondary curves develop. Our current strategy after documented progression is to recommend surgery at the age of five years and when 90% of the diameter of the spinal canal has already developed.

Cite this article: Bone Joint J 2013;95-B:1527–32.

There have been a few reports of patients with a combination of lumbar and thoracic spinal stenosis. We describe six patients who suffered unexpected acute neurological deterioration at a mean of 7.8 days (6 to 10) after lumbar decompressive surgery. Five had progressive weakness and one had recurrent pain in the lower limbs. There was incomplete recovery following subsequent thoracic decompressive surgery.

The neurological presentation can be confusing. Patients with compressive myelopathy due to lower thoracic lesions, especially epiconus lesions (T10 to T12/L1 disc level), present with similar symptoms to those with lumbar radiculopathy or cauda equina lesions. Despite the rarity of this condition we advise that patients who undergo lumbar decompressive surgery for stenosis should have sagittal whole spine MRI studies pre-operatively to exclude proximal neurological compression.

Cite this article: Bone Joint J 2013;95-B:1388–91.

Adolescent idiopathic scoliosis affects about 3% of children. Non-operative measures are aimed at altering the natural history to maintain the size of the curve below 40° at skeletal maturity. The application of braces to treat spinal deformity pre-dates the era of evidence-based medicine, and there is a paucity of irrefutable prospective evidence in the literature to support their use and their effectiveness has been questioned.

This review considers this evidence. The weight of the evidence is in favour of bracing over observation. The most recent literature has moved away from addressing this question, and instead focuses on developments in the design of braces and ways to improve compliance.

Cite this article: Bone Joint J 2013;95-B:1308–16.

The main form of treatment of a chordoma of the mobile spine is total en bloc spondylectomy (TES), but the clinical results are not satisfactory. Stand-alone carbon ion radiotherapy (CIRT) for bone and soft-tissue sarcomas has recently been reported to have a high rate of local control with a low rate of local recurrence.

We report two patients who underwent TES after CIRT for treating a chordoma in the lumbar spine with good medium-term outcomes. At operation, there remained histological evidence of viable tumour cells in both cases. After the combination use of TES following CIRT, neither patient showed signs of recurrence at the follow-up examination. These two cases suggest that CIRT should be combined with total spondylectomy in the treatment of chordoma of the mobile spine.

Cite this article: Bone Joint J 2013;95-B:1392–5.

We investigated the relationship between spinopelvic parameters and disc degeneration in young adult patients with spondylolytic spondylolisthesis. A total of 229 men with a mean age of 21 years (18 to 26) with spondylolytic spondylolisthesis were identified. All radiological measurements, including pelvic incidence, sacral slope, pelvic tilt, lumbar lordosis, sacral inclination, lumbosacral angle (LSA), and sacrofemoral distance, were calculated from standing lateral lumbosacral radiographs. The degree of intervertebral disc degeneration was classified using a modified Pfirrmann scale. We analysed the spinopelvic parameters according to disc level, degree of slip and disc degeneration.

There were significant positive correlations between the degree of slip and pelvic incidence (p = 0.009), sacral slope (p = 0.003) and lumbar lordosis (p = 0.010). The degree of slip and the LSA were correlated with disc degeneration (p < 0.001 and p = 0.003, respectively). There was also a significant difference between the degree of slip (p < 0.001) and LSA (p = 0.006) according to the segmental level of disc degeneration.

Cite this article: Bone Joint J 2013;95-B:1239–43.

We investigated the spinopelvic morphology and global sagittal balance of patients with a degenerative retrolisthesis or anterolisthesis. A total of 269 consecutive patients with a degenerative spondylolisthesis were included in this study. There were 95 men and 174 women with a mean age of 64.3 years (sd 10.5; 40 to 88). A total of 106 patients had a pure retrolisthesis (R group), 130 had a pure anterolisthesis (A group), and 33 had both (R+A group).

A backward slip was found in the upper lumbar levels (mostly L2 or L3) with an almost equal gender distribution in both the R and R+A groups. The pelvic incidence and sacral slope of the R group were significantly lower than those of the A (both p < 0.001) and R+A groups (both p < 0.001). The lumbar lordosis of the R+A group was significantly greater than that of the R (p = 0.025) and A groups (p = 0.014). The C7 plumb line of the R group was located more posteriorly than that of the A group (p = 0.023), but was no different from than that of the R+A group (p = 0.422). The location of C7 plumb line did not differ between the three groups (p = 0.068). The spinosacral angle of the R group was significantly smaller than that of the A group (p < 0.001) and R+A group (p < 0.001).

Our findings imply that there are two types of degenerative retrolisthesis: one occurs primarily as a result of degeneration in patients with low pelvic incidence, and the other occurs secondarily as a compensatory mechanism in patients with an anterolisthesis and high pelvic incidence.

Cite this article: Bone Joint J 2013;95-B:1244–9.

The belief that an intervertebral disc must degenerate before it can herniate has clinical and medicolegal significance, but lacks scientific validity. We hypothesised that tissue changes in herniated discs differ from those in discs that degenerate without herniation. Tissues were obtained at surgery from 21 herniated discs and 11 non-herniated discs of similar degeneration as assessed by the Pfirrmann grade. Thin sections were graded histologically, and certain features were quantified using immunofluorescence combined with confocal microscopy and image analysis. Herniated and degenerated tissues were compared separately for each tissue type: nucleus, inner annulus and outer annulus.

Herniated tissues showed significantly greater proteoglycan loss (outer annulus), neovascularisation (annulus), innervation (annulus), cellularity/inflammation (annulus) and expression of matrix-degrading enzymes (inner annulus) than degenerated discs. No significant differences were seen in the nucleus tissue from herniated and degenerated discs. Degenerative changes start in the nucleus, so it seems unlikely that advanced degeneration caused herniation in 21 of these 32 discs. On the contrary, specific changes in the annulus can be interpreted as the consequences of herniation, when disruption allows local swelling, proteoglycan loss, and the ingrowth of blood vessels, nerves and inflammatory cells.

In conclusion, it should not be assumed that degenerative changes always precede disc herniation.

Cite this article: Bone Joint J 2013;95-B:1127–33.

This study evaluates the long-term survival of spinal implants after surgical site infection (SSI) and the risk factors associated with treatment failure.

A Kaplan-Meier survival analysis was carried out on 43 patients who had undergone a posterior spinal fusion with instrumentation between January 2006 and December 2008, and who consecutively developed an acute deep surgical site infection. All were appropriately treated by surgical debridement with a tailored antibiotic program based on culture results for a minimum of eight weeks.

A ‘terminal event’ or failure of treatment was defined as implant removal or death related to the SSI. The mean follow-up was 26 months (1.03 to 50.9). A total of ten patients (23.3%) had a terminal event. The rate of survival after the first debridement was 90.7% (95% confidence interval (CI) 82.95 to 98.24) at six months, 85.4% (95% CI 74.64 to 96.18) at one year, and 73.2% (95% CI 58.70 to 87.78) at two, three and four years. Four of nine patients required re-instrumentation after implant removal, and two of the four had a recurrent infection at the surgical site. There was one recurrence after implant removal without re-instrumentation.

Multivariate analysis revealed a significant risk of treatment failure in patients who developed sepsis (hazard ratio (HR) 12.5 (95% confidence interval (CI) 2.6 to 59.9); p < 0.001) or who had > three fused segments (HR 4.5 (95% CI 1.25 to 24.05); p = 0.03). Implant survival is seriously compromised even after properly treated surgical site infection, but progressively decreases over the first 24 months.

Cite this article: Bone Joint J 2013;95-B:1121–6.

Mesenchymal stem-cell based therapies have been proposed as novel treatments for intervertebral disc degeneration, a prevalent and disabling condition associated with back pain. The development of these treatment strategies, however, has been hindered by the incomplete understanding of the human nucleus pulposus phenotype and by an inaccurate interpretation and translation of animal to human research. This review summarises recent work characterising the nucleus pulposus phenotype in different animal models and in humans and integrates their findings with the anatomical and physiological differences between these species. Understanding this phenotype is paramount to guarantee that implanted cells restore the native functions of the intervertebral disc.

Cite this article: Bone Joint Res 2013;2:169–78.

Whether to combine spinal decompression with fusion in patients with symptomatic lumbar spinal stenosis remains controversial. We performed a cohort study to determine the effect of the addition of fusion in terms of patient satisfaction after decompressive spinal surgery in patients with and without a degenerative spondylolisthesis.

The National Swedish Register for Spine Surgery (Swespine) was used for the study. Data were obtained for all patients in the register who underwent surgery for stenosis on one or two adjacent lumbar levels. A total of 5390 patients fulfilled the inclusion criteria and completed a two-year follow-up. Using multivariable models the results of 4259 patients who underwent decompression alone were compared with those of 1131 who underwent decompression and fusion. The consequence of having an associated spondylolisthesis in the operated segments pre-operatively was also considered.

At two years there was no significant difference in patient satisfaction between the two treatment groups for any of the outcome measures, regardless of the presence of a pre-operative spondylolisthesis. Moreover, the proportion of patients who required subsequent further lumbar surgery was also similar in the two groups.

In this large cohort the addition of fusion to decompression was not associated with an improved outcome.

Cite this article: Bone Joint J 2013;95-B:960–5.

Dysphagia is a common complication of anterior surgery of the cervical spine. The incidence of post-operative dysphagia may be as high as 71% within the first two weeks after surgery, but gradually decreases during the following months. However, 12% to 14% of patients may have some persistent dysphagia one year after the procedure. It has been shown that female gender, advanced age, multilevel surgery, longer operating time and severe pre-operative neck pain may be risk factors. Although the aetiology remains unclear and is probably multifactorial, proposed causes include oesophageal retraction, prominence of the cervical plate and prevertebral swelling. Recently, pre-operative tracheal traction exercises and the use of retropharyngeal steroids have been proposed as methods of reducing post-operative dysphagia.

We performed a systematic review to assess the incidence, aetiology, risk factors, methods of assessment and management of dysphagia following anterior cervical spinal surgery.

Cite this article: Bone Joint J 2013;95-B:868–73.

The purpose of this study was to determine whether it would be feasible to use oblique lumbar interbody fixation for patients with degenerative lumbar disease who required a fusion but did not have a spondylolisthesis.

A series of CT digital images from 60 patients with abdominal disease were reconstructed in three dimensions (3D) using Mimics v10.01: a digital cylinder was superimposed on the reconstructed image to simulate the position of an interbody screw. The optimal entry point of the screw and measurements of its trajectory were recorded. Next, 26 cadaveric specimens were subjected to oblique lumbar interbody fixation on the basis of the measurements derived from the imaging studies. These were then compared with measurements derived directly from the cadaveric vertebrae.

Our study suggested that it is easy to insert the screws for L1/2, L2/3 and L3/4 fixation: there was no significant difference in measurements between those of the 3-D digital images and the cadaveric specimens. For L4/5 fixation, part of L5 inferior articular process had to be removed to achieve the optimal trajectory of the screw. For L5/S1 fixation, the screw heads were blocked by iliac bone: consequently, the interior oblique angle of the cadaveric specimens was less than that seen in the 3D digital images.

We suggest that CT scans should be carried out pre-operatively if this procedure is to be adopted in clinical practice. This will assist in determining the feasibility of the procedure and will provide accurate information to assist introduction of the screws.

Cite this article: Bone Joint J 2013;95-B:977–82.

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.

The purpose of this study was to investigate the clinical predictors of surgical outcome in patients with cervical spondylotic myelopathy (CSM). We reviewed a consecutive series of 248 patients (71 women and 177 men) with CSM who had undergone surgery at our institution between January 2000 and October 2010. Their mean age was 59.0 years (16 to 86). Medical records, office notes, and operative reports were reviewed for data collection. Special attention was focused on pre-operative duration and severity as well as post-operative persistence of myelopathic symptoms. Disease severity was graded according to the Nurick classification.

Our multivariate logistic regression model indicated that Nurick grade 2 CSM patients have the highest chance of complete symptom resolution (p < 0.001) and improvement to normal gait (p = 0.004) following surgery. Patients who did not improve after surgery had longer duration of myelopathic symptoms than those who did improve post-operatively (17.85 months (1 to 101) vs 11.21 months (1 to 69); p = 0.002). More advanced Nurick grades were not associated with a longer duration of symptoms (p = 0.906).

Our data suggest that patients with Nurick grade 2 CSM are most likely to improve from surgery. The duration of myelopathic symptoms does not have an association with disease severity but is an independent prognostic indicator of surgical outcome.

Cite this article: Bone Joint J 2013;95-B:966–71.

Ventral screw osteosynthesis is a common surgical method for treating fractures of the odontoid peg, but there is still no consensus about the number and diameter of the screws to be used. The purpose of this study was to develop a more accurate measurement technique for the morphometry of the odontoid peg (dens axis) and to provide a recommendation for ventral screw osteosynthesis.

Images of the cervical spine of 44 Caucasian patients, taken with a 64-line CT scanner, were evaluated using the measuring software MIMICS. All measurements were performed by two independent observers. Intraclass correlation coefficients were used to measure inter-rater variability.

The mean length of the odontoid peg was 39.76 mm (sd 2.68). The mean screw entry angle α was 59.45° (sd 3.45). The mean angle between the screw and the ventral border of C2 was 13.18° (sd 2.70), the maximum possible mean converging angle of two screws was 20.35° (sd 3.24). The measurements were obtained at the level of 66% of the total odontoid peg length and showed mean values of 8.36 mm (sd 0.84) for the inner diameter in the sagittal plane and 7.35 mm (sd 0.97) in the coronal plane. The mean outer diameter of the odontoid peg was 12.88 mm (sd 0.91) in the sagittal plane and 11.77 mm (sd 1.09) in the coronal plane. The results measured at the level of 90% of the total odontoid peg length were a mean of 6.12 mm (sd 1.14) for the sagittal inner diameter and 5.50 mm (sd 1.05) for the coronal inner diameter. The mean outer diameter of the odontoid peg was 11.10 mm (sd 1.0) in the sagittal plane and 10.00 mm (sd 1.07) in the coronal plane. In order to calculate the necessary screw length using 3.5 mm cannulated screws, 1.5 mm should be added to the measured odontoid peg length when anatomical reduction seems possible.

The cross-section of the odontoid peg is not circular but slightly elliptical, with a 10% greater diameter in the sagittal plane. In the majority of cases (70.5%) the odontoid peg offers enough room for two 3.5 mm cannulated cortical screws.

Cite this article: Bone Joint J 2013;95-B:536–42.

In a retrospective cohort study we compared the clinical outcome and complications, including dysphagia, following anterior cervical fusion for the treatment of cervical spondylosis using either a zero-profile (Zero-P; Synthes) implant or an anterior cervical plate and cage. A total of 83 patients underwent fusion using a Zero-P and 107 patients underwent fusion using a plate and cage. The mean follow-up was 18.6 months (sd 4.2) in the Zero-P group and 19.3 months (sd 4.1) in the plate and cage group. All patients in both groups had significant symptomatic and neurological improvement. There were no significant differences between the groups in the Neck Disability Index (NDI) and visual analogue scores at final follow-up. The cervical alignment improved in both groups. There was a higher incidence of dysphagia in the plate and cage group on the day after surgery and at two months post-operatively. All patients achieved fusion and no graft migration or nonunion was observed.

When compared with the traditional anterior cervical plate and cage, the Zero-P implant is a safe and convenient procedure giving good results in patients with symptomatic cervical spondylosis with a reduced incidence of dysphagia post-operatively.

Cite this article: Bone Joint J 2013;95-B:543–7.

This is a prospective randomised study comparing the clinical and radiological outcomes of uni- and bipedicular balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures. A total of 44 patients were randomised to undergo either uni- or bipedicular balloon kyphoplasty. Self-reported clinical assessment using the Oswestry Disability Index, the Roland-Morris Disability questionnaire and a visual analogue score for pain was undertaken pre-operatively, and at three and twelve months post-operatively. The vertebral height and kyphotic angle were measured from pre- and post-operative radiographs. Total operating time and the incidence of cement leakage was recorded for each group.

Both uni- and bipedicular kyphoplasty groups showed significant within-group improvements in all clinical outcomes at three months and twelve months after surgery. However, there were no significant differences between the groups in all clinical and radiological outcomes. Operating time was longer in the bipedicular group (p < 0.001). The incidence of cement leakage was not significantly different in the two groups (p = 0.09).

A unipedicular technique yielded similar clinical and radiological outcomes as bipedicular balloon kyphoplasty, while reducing the length of the operation. We therefore encourage the use of a unipedicular approach as the preferred surgical technique for the treatment of osteoporotic vertebral compression fractures.

Cite this article: Bone Joint J 2013;95-B:401–6.

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.