Mini Abstract: Pregnancy-associated osteoporosis (PAO) is a rare syndrome affecting women during late pregnancy and the early postpartum period. We set out to review the clinical features of ten cases of PAO from a single UK centre. Patients had attended the Royal National Hospital for Rheumatic Diseases, Bath (RNHRD) between January 2000 and June 2016. The principal criterion for inclusion was the occurrence of low trauma fractures either during pregnancy or the immediate post-partum period. Data were obtained from retrospective review of medical notes. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (Hologic ®Discovery system) at the lumbar spine and hip. Data pertaining to the pregnancy, as well as type and duration of treatment received, were reviewed. All ten cases presented with vertebral fractures. In four patients, no risk factors for fracture other than pregnancy or breastfeeding could be identified. Four patients were found to have vitamin D insufficiency at the time of diagnosis, and a further two patients had received treatment with low molecular weight heparin (LMWH). In one case, further investigation led to a diagnosis of osteogenesis imperfecta (OI) confirmed on genetic testing. In terms of treatment, eight out of the ten patients in this series received a bisphosphonate, most commonly risedronate due to its relatively short skeletal retention time. Clinicians should be aware of PAO, a rare but recognised complication of pregnancy. The condition should be especially considered in women presenting with new onset back pain in pregnancy or the postpartum period.
The objective of this cadaveric study is to determine the safety and outcome of thoracic pedicle screw placement in Asians using the funnel technique. Pedicle screws have superior biomechanical as well as clinical data when compared to other methods of instrumentation. However, misplacement in the thoracic spine can result in major neurological implications. There is great variability of the thoracic pedicle morphometry between the Western and the Asian population. The feasibility of thoracic pedicle screw insertion in Asians has not been fully elucidated yet. A pre-insertion radiograph was performed and surgeons were blinded to the morphometry of the thoracic pedicles. 240 pedicle screws were inserted in ten Asian cadavers from T1 to T12 using the funnel technique. 5.0 mm screws were used from T1 to T6 while 6.0 mm screws were used from T7 to T12. Perforations were detected by direct visualization via a wide laminectomy. The narrowest pedicles are found between T3 and T6. T5 pedicle width is smallest measuring 4.1 +/- 1.3 mm. There were 24 (10.0%) Grade 1 perforations and only 1 (0.4%) Grade 2 perforation. Grade 2 or worse perforation is considered significant perforation which would threaten the neural structures. There were twice as many lateral and inferior perforations compared to medial perforations. 48.0% of the perforations occurred at T1, T2 and T3 pedicles. Pedicle fracture occurred in 10.4% of pedicles. Intra-operatively, the absence of funnel was found in 24.5% of pedicles. In conclusion, thoracic pedicle screws using 5.0 mm at T1-T6 and 6.0 mm at T7-T12 can be inserted safely in Asian cadavers using the funnel technique despite having smaller thoracic pedicle morphometry.