A novel use of cone beam CT: flexion and extension weight-bearing imaging to assess spinal stability.

PURPOSE: To assess spinal stability in different physiological positions whilst weight-bearing. METHODS: A cone beam CT scanner (CBCT) was used to identify any abnormal motion in the spine in different physiological positions whilst weight-bearing. The lumbar spine was assessed in 6 different patients with a comfortable neutral standing position and standing flexion and extension images in selected patients. Seated, weight-bearing flexion and extension images of the cervical spine were obtained in a further patient. Clinical indications included stability assessment post-trauma, post-surgical fusion and back pain. The projection images were reconstructed using bone and soft tissue algorithms to give isotropic CT images which could be viewed as per conventional multi-detector CT images. The flexion and extension CBCT data were fused to give a representation of any spinal movement between the extremes of motion. RESULTS: The flexion and extension weight-bearing images gave anatomical detail of the spine. Detail of the surgical constructs was possible. Dynamic structural information about spinal alignment, facet joints, exit foramina and paraspinal musculature was possible. The effective dose from the neutral position was equal to that of supine, multi-detector CT. CONCLUSION: CBCT can be used to image the lumbar and cervical spine in physiological weight-bearing positions and at different extremes of spinal motion. This novel application of an existing technology can be used to aid surgical decision making to assess spinal stability and to investigate occult back and leg pain. Its use should be limited to specific clinical indications, given the relatively high radiation dose.

Spinal Motocross Injuries in the United Kingdom.

BACKGROUND: Motocross is a form of motorcycle racing held on established off-road circuits and has been a recreational and competitive sport across the world for >100 years. In the United Kingdom alone, motocross has grown into a phenomenally ambitious and popular franchise. There are >200 motocross clubs across the country, permitting >900 events annually. PURPOSE: To assess the current trend of spine-related motocross injuries over the past 5 years. STUDY DESIGN: Descriptive epidemiology study. METHODS: Data were prospectively collected over 5 years (August 2010-August 2015) at our regional trauma and spine unit, regardless of whether the rider was performing the sport competitively or recreationally. RESULTS: During the study period, spine-related injuries were identified for 174 patients (age range, 6-75 years) who were directly referred to our department following recreational or competitive motocross, with most injuries being sustained within the early spring and summer months, representing the start of the motocross season. A significant number of injuries were in males (n = 203, 94%), with the majority of injuries occurring within the 21- to 30-year-old age group. A total of 116 (54%) injuries required operative treatment. The most common spinal injury was thoracolumbar burst fracture (n = 95), followed by chance fractures (n = 26). CONCLUSION: This data series emphasizes the prevalence and devastation of motocross-related spinal injuries in the United Kingdom and may serve in administering sanctions and guidelines to governing bodies of motocross. The spinal injuries that occur during motocross have significant capital connotations for regional spinal centers. The recent surge in motocross popularity is correlated with the number of injuries, which have increased over the past 5 years by almost 500%.

Minimally invasive spinal surgery for the management of symptomatic spinal metastasis.

INTRODUCTION: Symptomatic metastatic spinal disease is on the increase. Minimally invasive spinal surgery has been associated with a lower complication profile when compared to traditional open methods; however there is paucity of literature evaluating the place of percutaneous pedicle screw fixation (PPSF) in the management of spinal metastases. The purpose of the study is to assess the efficacy of Minimally Invasive Spine Surgery (MISS) using PPSF with or without mini-decompression in the management of symptomatic spinal metastases. MATERIAL AND METHODS: This is a single institution prospective study of 51 consecutive patients with metastatic spinal disease treated with PPSF. Patients presenting with pathological compression fractures and mechanical instability had PPSF, and those with radiological and/or clinical metastatic spinal cord compression (MSCC) underwent an additional mini-decompression. Data collected included patient demographics, Karnofsky's performance status (KPS), pain scores and neurology. Other data included number and location of involved levels, number of instrumented levels, blood loss, accuracy of screw placement and complications. RESULTS: Of the 51 patients, 49 could be successfully treated with MISS (26 females and 23 males). 26 patients (55%) required a mini-decompression. 27 patients (55%) had improvement in KPS by at least 10 points (p < 0.0005). Only 2 patients (4%) had a worsening of KPS, due to other coexisting problems. Six of the 13 patients improved their neurology by one Frankel grade following surgery and 95% reported improvement in pain. Mean blood loss was 92mls for the fixation only group and 222mls for those requiring mini-decompression, with no other differences between these two surgical groups. Screw positioning was excellent in 91%, with 98% having uncompromised bony hold. Only two patients required revision surgery for aseptic loosening. CONCLUSION: MISS using PPSF is a safe and reproducible technique that maintains or improves functional outcome in the vast majority of patients presenting with spinal metastases.

Validation of a novel smartphone accelerometer-based knee goniometer.

Loss of full knee extension following anterior cruciate ligament surgery has been shown to impair knee function. However, there can be significant difficulties in accurately and reproducibly measuring a fixed flexion of the knee. We studied the interobserver and the intraobserver reliabilities of a novel, smartphone accelerometer-based, knee goniometer and compared it with a long-armed conventional goniometer for the assessment of fixed flexion knee deformity. Five healthy male volunteers (age range 30 to 40 years) were studied. Measurements of knee flexion angle were made with a telescopic-armed goniometer (Lafayette Instrument, Lafayette, IN) and compared with measurements using the smartphone (iPhone 3GS, Apple Inc., Cupertino, CA) knee goniometer using a novel trigonometric technique based on tibial inclination. Bland-Altman analysis of validity and reliability including statistical analysis of correlation by Pearson's method was undertaken. The iPhone goniometer had an interobserver correlation (r) of 0.994 compared with 0.952 for the Lafayette. The intraobserver correlation was r = 0.982 for the iPhone (compared with 0.927). The datasets from the two instruments correlate closely (r = 0.947) are proportional and have mean difference of only -0.4 degrees (SD 3.86 degrees). The Lafayette goniometer had an intraobserver reliability +/- 9.6 degrees. The interobserver reliability was +/- 8.4 degrees. By comparison the iPhone had an interobserver reliability +/- 2.7 degrees and an intraobserver reliability +/- 4.6 degrees. We found the iPhone goniometer to be a reliable tool for the measurement of subtle knee flexion in the clinic setting.

Osteoid osteoma: can impedance levels in radiofrequency thermocoagulation predict recurrence?

Objective. To evaluate rise in impedance during percutaneous radiofrequency thermocoagulation (PRFTC) of osteoid osteomas as a predictor of local recurrence. Design and Patients. A prospective study of 23 patients (24 PRFTC procedures) with minimum of 2.25-year followup (average 3.3 years). Average age 19.6 years (range 4-44), sex ratio 15 : 8 (male : female), 16 nondiaphyseal, 7 diaphyseal. Results. In 19 procedures, an increase in impedance was measured-no recurrences have occurred in this group to date. In 5 procedures, no increase in impedance was seen (3 non-diaphyseal, 2 diaphyseal), and 1 recurrence has been seen in this group to date. This difference is statistically significant with a P value of .05.

The outcome of locking plate fixation for the treatment of periarticular metastases.

Periarticular bone metastasis may be treated with endoprosthetic reconstruction. The extensive surgery required may not, however, be appropriate for all patients. Our aim was to establish whether locking plates provide good functional outcomes and a durable construct when used in the management of metastatic disease. Prospective data collection was performed. Twenty one patients underwent surgery for periarticular metastatic tumours. The median duration of followup for surviving patients is one year. There have been no cases of implant failure and no requirement for revision surgery. Pain relief was excellent or good in the majority of patients. Patients who had sustained a fracture prior to fixation had restoration of their WHO performance status. All patients had a dramatic improvement in their MSTS scores. The median pre-operative score was 15% (0%-37%) improving to a median score of 80% (75%-96%) post operatively. Locking plates were found to provide reliable fixation and excellent functional restoration in selected patients suffering from periarticular metastatic bone disease.