Klinisch-funktionelle Nachuntersuchung von Patienten, die mittels B-Twin Expandable-Spinal-Spacer an der Lendenwirbelsäule operiert wurden

The best possible treatment of degenerative spondylolisthesis, which is one of the most common reasons of chronic low back pain for older patients and one of the principal causes for lumbar spinal stenosis, is being discussed in many ways and is not finally settled. The best possible therapeutic procedure for secondary instabilities caused by an implemented decompression of spinal stenosis as well as the ideal treatment of recurrent spinal disc herniation in the lumbar spine with consecutive narrowed space between the two vertebrae is not resolved adequately either. At the moment various methods of treatment are being pursued: conservative approaches, minimally invasive lumbar interbody fusion, anterior and posterior lumbar interbody fusion and dynamic stabilization. The operative treatment of the back pain caused by instabilities with the PLIF technique is established for years and achieves good results. Up till now, no PLIF implant could be identified as superior. The good results are being aggrieved by the rate of complications. Injuries of the dura occur in 5,4 %. 9-16 % of the patients are infringed at the nerve root. The featured B-Twin-implant is a relatively new course of treatment, which was put to use as a stand-alone-PLIF (posterior lumbar interbody fusion) at the patients collective with the indications described above. The B-Twin is a so called “Expandable Spinal Spacer”. The biggest difference between the B-Twin implant and conventional PLIF-Cages can be derived from the terminology already. Contrary to the conventional implants, the B-Twin is not brought to its full size until it is located in the disk space. The advantages of this way of implanting are above all conservation of the surrounding structures as the muscular system, cauda equina and nerve roots. Overall a collective of 97 patients was examined. The indication for surgery was a degenerative spondylolisthesis at 67 patients, a secondary instability after operative decompression of a spinal stenosis at 15 patients and in 15 patients the indication for surgery was a degenerative disc disease. At the time of the check-up the implantation was in average 26 months ago. 56 patients were female (57,7 %) and 41 were male (42,3 %). In average the patient was 61,2 years of age. The physical condition after the operation using the B-Twin procedure improved significantly. Patients stated that their back pain improved, shortly after the operation as well as more than two years later (VAS T1=8,7 SD=1,45; VAS T2=3,57 SD=2,80; VAS T3=3,74 SD=2,60; p<0.05). Limitations of every day activities by back pain were also improved after the B-Twin operation (ODI T1=36,60 SD=11,86; ODI T3=22,09 SD=9,06; p<0.01). Non of the patients was hurt at the dura, the nerve root or a major bloodvessel. Moreover the results of this study were compared with other studies by the systematic integration of the results into the database of the B-Twin-procedure. For this all published studies about the B-Twin-procedure until the first of June 2010 were taken into consideration. All in all the post operative results of 261 patients were being evaluated. A clear improvement of the health of the patients was proven. This was verified with scores as well as clinical and functional parameters. This study has a retrospective and mono-centric design without a control group. The design does not comply with the maximum standard of a prospective and randomized control trial (RCT). Primary goal for further studies should be to identify characteristics of patients, benefitting from a B-Twin surgery. This study shows the effectiveness of the B-Twin procedure with a group of carefully selected patients. This study shows indications of a bigger advantage from B-Twin surgery for patients, whose back pains are not chronically yet (duration of grievance less than two years). Further studies, especially prospective and multi centric ones, are still needed though.