B-twin expandable spinal spacer for treatment of degenerative disc disease A 30-case retrospective analysis / 中国组织工程研究

ABSTRACT

A total of 30 patients with degenerative disc disease underwent posterior lumbar interbody fusion (PLIF) using a B-twin expandable spinal spacer (ESS) at the Department of Orthopedics,First Hospital,Peking University between August 2005 and February 2008 and were retrospectively analyzed.These patients consisted of 14 males and 16 females and averaged 28-72 years old.PLIF was performed at L1/2 in 1 patient,at L2/3 in 1 patient,at L3/4 in 1 patient,at L4/5 in 14 patients,and at L5/S1 in 13 patients.Patients underwent PLIF using simple B-twin ESS (n=8,1 employing single spacer,and 7 a pair of spacers) or B-twin ESS combined with pedicle screw (n=22,17 employing single placer,and 5 a pair of placers).B-twin ESS with a diameter of 9.5-11.0 mm was used in 28 patients and with a diameter of 11.5-13.0 mm in 2 patients.Examinations were carried out before surgery,post surgery,and during follow-up.Clinical symptoms were assessed using a 29-point Japanese Orthopaedic Association (JOA) score rating system.Spinal dysfunction was evaluated using the Oswestry Disability Index (ODI).The intervertebral space height and slippage reduction were measured through X-ray images.Twenty-eight of thirty patients were averagely followed up for 9 months.The excellent and good rate of ODI was 97% post surgery and 100% during follow-up period.The excellent and good rate of JOA was 93% post surgery and 96% during follow-up period.The proportion of intervertebral space height in upper vertebra that averaged 0.29±0.09 before surgery increased to 0.44±0.09 post surgery and stabilized at 0.4±0.09 upon final follow-up.The slippage was 10%-60% of upper vertebra before surgery,0%-40% post surgery,and 0%-30% till final follow-up.No neurological impairment or infection was found.There was 1 patient suffering from dural tear for adherence during decompression,1 patient presenting implant subsidence into the endplate post surgery,and 1 patient exhibiting spacer fragmentation during follow-up period.All outcomes indicate that B-twin ESS is characterized by minimal invasion,short surgery time,and less neurostimulation and provides satisfactory postoperative and follow-up efficiency.Attention should be paid to selecting suitable spacer type according to preoperative and intraoperative measurements.There is a breakage possibility if the spacer is put on one side of the space.To avoid this,sufficient bone graft is essential and two spacers may be put in one vertebra space if necessary.