Comparison of Topping-off and posterior lumbar interbody fusion surgery in lumbar degenerative disease： a retrospective study

Background Topping-off surgery is a newly-developed surgical technique which combines rigid fusion with an interspinous process device in the adjacent segment to prevent adjacent segment degeneration. There are few reports on Topping-off surgery and its rationality and indications remains highly controversial. Our study aims to investigate the short-term and mid-term clinical results of Topping-off surgery in preventing adjacent segment degeneration when mild or moderate adjacent segment degeneration existed before surgery. Methods The 25 cases that underwent L5-$1 posterior lumbar interbody fusion （PLIF） ＋ L4-L5 interspinous process surgeries between April 2008 and March 2010 formed Topping-off group. The 42 cases undergoing L5-$1 PLIF surgery formed PLIF group. Both groups matched in gender, age, body mass index and Pfirrmann grading （4 to 6）. The patients were evaluated with visual analogue scale （VAS） and Japanese orthopaedic association （JOA） scores before surgery and in the last follow-up. Modic changes of endplates were recorded. Results The follow-up averaged 24.8 and 23.7 months. No symptomatic or radiological adjacent segment degeneration was observed. There was no significant difference in intraoperative blood loss or postoperative drainage. VAS and lumbar JOA scores improved significantly in both groups （t=-12.1 and 13.5, P 〈0.05）. Neither anterior nor posterior disc height was significantly changed. Segmental lordosis of L4-L5 and total lordosis were all increased significantly （Topping-off group： t=-2.30 and -2.24, P 〈0.05; PLIF group： t=--2.76 and -1.83, P 〈0.01）. In the hyperextension and hyperflexion view, Topping-off group＇s range of motion （ROM） and olisthesis in the L4-L5 segment did not significantly change in flexion, but decreased in extension. In PLIF group, ROM （t=--7.82 and -4.90, P 〈0.01） and olisthesis （t=--15.67 and -18.58, P 〈0.01） both significantly increased in extension and flexion. Conclusions Compared with single segment PLIF surgery, Topping-off surgery can achieve similar symptomatic improvement in cases with pre-existing mild or moderate adjacent segment degeneration, restrict the adjacent segment＇s ROM in extension and prevent excessive olisthesis of adiacent seament in both extension and flexion

Complications and clinical outcomes of minimally invasive transforaminal lumbar interbody fusion for the treatment of one- or two.-level degenerative disc diseases of the lumbar spine in patients older than 65 years

Background Minimally invasive transforaminal lumbar interbody fusion （MIS-TLIF） has been successfully used to treat degenerative diseases of the lumbar spine. There are few reports comparing the complications and clinical outcomes in older patients who have undergone one- or two-level MIS-TLIF with those of younger patients. The aim of this study was to investigate the clinical outcomes of MIS-TLIF in the treatment of degenerative disc disease of lumbar spine of the patients older than 65 years, with an emphasis on perioperative complications compared to the younger patients. Methods One hundred and fifty-one consecutive cases of one- or two-level degenerative disc disease of lumbar spine treated with MIS-TLIF were reviewed for the radiological and clinical outcomes. They were divided into elderly group （age 〉65 years old） and younger group （age 〈65 years old）, and were followed for at least 6 months. Radiographs were obtained before and after surgery, 3 months postoperatively, and at the final follow-up to determine the presence of fusion, hardware-related problems. The clinical outcomes were evaluated using the Oswestry Disability Index （ODI） before and after surgery, and at the final follow-up. The visual analogue scale （VAS） score of back and leg pain were evaluated as well. The intra-operative data and peri-operative complications were recorded. Results The mean age of these patients at operation was （57.7±14.2） years （range 26-82 years）. Of 151 patients, 62 were 65 years or older. The elderly patients had more comorbidities and more porportion of lumbar canal stenosis. The overall fusion rate was 88.4% at the final follow-up, with no significant difference between younger and elderly patients. The ODI, the VAS of back pain and radicular pain of both young and elderly group were significantly improved after surgery and at the final follow-up, without significant difference between two groups. There were 16 complications with an incidence of 10.6%, including 7 major complications and 9 minor complications. There was no significant difference of the incidence of complications between two groups. The incidence of dura tear was significantly related to bilateral deompression. Conclusions The clinical and radiological outcomes of MIS-TLIF in the treatment of one- or two-level degenerative disc diseases of lumbar spine in the elderly patients were satisfactory. Though there are more pre-operative comorbidities, with proper patient selection, the elderly patients are not at increased risk of perioperative complications compared to younger patients. Screw malposition and dura tear, which are the most frequent complications, were more related to the surgical technique and should be avoided.

Minimally invasive transforaminal lumbar interbody fusion aided with computer-assisted spinal navigation system combined with electromyography monitoring

Background Minimally invasive techniques are gaining wide-spread application in lumbar fusion surgery, because they may have advantage over conventional open surgery in approach-related morbidity. This research was aimed to evaluate the safety and accuracy of the techniques of minimally invasive transforaminal lumbar interbody fusion by using a computer-assisted spinal navigation system combined with electromyography monitoring. Methods Sixteen patients underwent minimally invasive transforaminal lumbar interbody fusion. A computer-assisted spinal navigation system and electromyography were used for guiding pedicle screw placement. The operative duration, blood loss, complications, and fluoroscopic time were recorded. Clinical outcome was assessed by Visual Analog Scale and Oswestry Disability Index. Radiographic images were obtained to evaluate the accuracy of pedicle screw placement and fusion rates. Results The Visual Analog Scale and Oswestry Disability Index scores were vastly improved postoperatively. A total of 64 pedicle screws were implanted and three were regarded as misplacement by post-operative CT scan. Three screw trajectories were adjusted according to intra-operative stimulus-evoked electromyography monitoring. The average fluoroscopy time in each patient was 31.8 seconds, which equals to 7.9 seconds per pedicle screw. No patients had instrument related neurological complications, infection, implant failure or revision. Successful fusion was found in all patients. Conclusions The combination of navigation system and real-time electromyography monitoring can make the minimally invasive operation more safe and accurate while decreasing radiation exposure time of the medical staff and patient and minimizing the chance and the degree of the pedicle screw misplacement.