The feasibility of interbody fusion with local autogenous bone harvested from unilateral interlaminar fenestration in PLIF

English Keywords:Posterior lumbar interbody fusion  Local autogenous bone  Bone graft  Quantization  Unilateral fenestration

English Abstract:

  【Abstract】 Objectives: To quantitatively observe the interbody fusion with local autogenous bone(LAB) harvested from unilateral interlaminar fenestration(UIF) in posterior lumbar interbody fusion(PLIF) and its feasibility. Methods: From January 2011 to December 2012, 107 patients underwent PLIF only using LAB+one cage and internal fixation with pedicle screw by the fenestration method designed by our team at L4/5 and/or L5/S1 of lumbar disc degenerative diseases(DDD). There were 52 males and 55 females with an average age of 52.8±9.0 years(range, 26-75 years) and with a mean medical history of 69.9±70.7 months(range, 6-240 months). A UIF was looked upon as one fenestration unit. The mass and volume of LAB from UIF were measured by analytical balance and 5ml disposal sterile syringe after LAB was made into the granular of diameter of 2-3mm. The heights of cages used intraoperatively were recorded. The area of endplate(Se) and the contact area(Sc) between the cartilaginous endplate and LAB+cage at every intervertebral space were measured and calculated by PACS of CT workstation after operation. The fusion status was estimated by three dimensional CT(3D-CT) and the JOA scores of preoperation and postoperation were compared at 3, 6, 12, 24 months postoperatively. Results: 113 segments of 107 patients were successfully operated. The mass and volume of LAB from UIF showed no significant differences at age, gender, segment and type of DDD(P＞0.05), and the same result existed about the Se and height of interbody space in L4/5 or L5S1 segments(P＞0.05). The mean mass and volume of LAB were 3.7±0.3g(range, 2.8-4.4g) and 3.1±0.3cm3（range，2.6-4.2cm3） from UIF. The packing ratio(PR) of intervertebral space with LAB+one cage was 38%. The volume and mass of LAB of 2.5cm3 and 3.0g were need to reach 30% PR in the operated intervertebral space. 94 cases(98 segments) were followed up for a mean of 24.3±5.9months(range, 24-28 months) postoperatively. The average improvement rate of JOA score was (83.5±7.7)%(range, 65%-100%), and the fusion rate was 97.9% in the end. No loosening and breakage of instrument and the subsidence of cage were noted. Conclusions: The local autogenous bone harvested from unilateral interlamiar enlarged fenestration is more than 2.5cm3 that can provide enough bone for lumbar interbody fusion combined with one cage in PLIF. The relevant complications of other bone graft substitutes will be avoided and the expense can be saved simultaneously.