Analysis of clinical efficacy of unilateral open-door cervical laminoplasty combined with foraminotomy for cervical ossification of posterior longitudinal ligament / 中国骨伤

<p><b>OBJECTIVE</b>To explore the clinical efficacy of unilateral open-door laminoplasty combined with foraminotomy for cervical ossification of posterior longitudinal ligament(OPLL).</p><p><b>METHODS</b>The clinical data of 45 patients with OPLL underwent surgical treatment between September 2011 and September 2015 were retrospectively analyzed. There were 26 males and 19 females with a mean age of 53.6 years old(ranged from 28 to 71 years). Among them, 24 cases received the surgery of unilateral open-door cervical laminoplasty combined with foraminotomy(combined group), and 21 cases received a single unilateral open-door cervical laminoplasty(single group). Operation time, intraoperative blood loss, complications including C₅ nerve root palsy and axial symptoms were compared between two groups. Pre-and post-operative Japanese Orthopedic Association(JOA) score, improvement rate of neurological function, Neck Disability Index(NDI) score, and cervical Cobb angle were recorded and analyzed between the two groups.</p><p><b>RESULTS</b>All the patients were followed up for 12-24 months, with an average of (14.3±2.8) months for combined groups and (13.7±3.1) months for single group, and no significant difference was found between the two groups(>0.05). There was no significant difference in operation time and intraoperative blood loss between two groups(>0.05). Postoperative JOA scores obtained obvious improvement in all patients(<0.05). However, there was no significant difference between two groups for the improvement rate of neurological function(>0.05). At final follow-up, NDI scores of combined group and single group were 13.6±1.8 and 16.1±2.4 respectively, there was significant difference between two groups(<0.05). The incidence of C₅ nerve root palsy was lower in combined group(4.2%) than that of single group (28.6%). There was no significant difference in incidence rate of axial symptoms between two groups(>0.05). There was no significant difference in cervical Cobb angle between pre-and post-operative conditions, or between two groups(>0.05).</p><p><b>CONCLUSIONS</b>Unilateral open-door cervical laminoplasty combined with foraminotomy is an effective method to treat cervical OPLL, which could provide sufficient decompression of spinal cord and nerve root, prevent the C₅ nerve root palsy.</p>

Pedicle exposure technique for atlas screw fixation:a radiological research / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the meaning of pedicle exposure technique for screw fixation on atlas with the vertebral groove height less than 4 mm by using reconstructive computed tomography.</p><p><b>METHODS</b>From April 2015 to June 2015, 84 pedicles of 51 patients with groove heights less than 4 mm were studied by digital reconstruction respectively. Parameters of atlas pedicle screw fixation were measured.</p><p><b>RESULTS</b>Among the 51 cases, the vertebral groove height was (3.28±0.51) mm. Lateral mass heights, lateral mass widths and the transition area heights between lateral mass and posterior arch were fit for 3.5 mm screw implanting. Ideal pedicle screw trajectory lengths from 0° to 15° (0°, 5°, 10°, 15°) were (27.36±1.81), (27.01±1.68), (27.07±1.75), (27.48±1.72) mm, exposed trajectory lengths from 0° to 15°(0°, 5°, 10°, 15°) were(23.44±1.79), (23.87±1.84), (24.58±1.89), (25.56±2.01) mm, trajectory length of lateral mass was (20.78±2.05) mm. The mean CT values on 5 sections through pedicle trajectory and lateral mass trajectory were (701.89±141.48) HU and (599.11±137.33) HU, respectively. There were no significant differences between ideal pedicle trajectory lengths from 0° to 15°(>0.05). Exposed trajectory lengths was significantly increased accompanying with medial angles increasing (<0.05), and was longer than trajectory lengths of lateral mass (<0.05). CT value of pedicle screws was higher than CT value of lateral mass screws significantly (<0.01).</p><p><b>CONCLUSIONS</b>Screws can be implanted in atlas with vertebral groove height less than 4 mm by using pedicle exposure technique. Few trajectory lengths will be sacrificed with favorable pull out strength due to adequate bone mass purchased.</p>