Objective To review the present clinical research situation of adjacent segment degeneration (ASD) after lumbar spinal fusion. Methods The recent literature concerning ASD in the concept, the incidence, the risk factors, and prevention was reviewed. Results The concept of ASD includes radiographic ASD and clinical ASD. The incidences of radiographic ASD and clinical ASD were 8%-100% and 5.2%-18.5%, respectively. The risk factors for ASD include both patient and surgical factors. Patient factors include age, gender, preoperative condition, and so on. Surgical factors include the length of the fusion, mode of fusion, internal fixator, sagittal balance, excessive distraction of disc space, and so on. It can prevent ASD to reduce the length of the fusion, to keep sagittal balance, and to use the non-fusion technology. Conclusion Many researches have proved that the incidence of ASD is increased after lumbar spinal fusion, and it can be reduced by the non-fusion technology. Non-fusion technology has obtained good short-term results. But the long-term results should be further observed because there are some complications.
Objective To study the effectiveness of artificial disc replacement for cervical diseases and the adjacent segment degeneration. Methods Between January 2008 and October 2010, 39 cases of cervical spondylosis underwent cervical disc replacement. Of them, there were 20 males and 19 females with an average age of 45.7 years (range, 32-60 years)and an average disease duration of 30 months (range, 1 month to 10 years), including 26 cases of cervical myelopathy, 11 cases of nerve root cervical spondylosis, and 2 cases of mixed cervical spondylosis. Single level disc lesion was observed in 27 cases while bi-level lesion in 12 cases. Prestige disc prosthesis was used in 9 patients, Prodisc-C prosthesis in 4 patients, and Discover disc prosthesis in 26 patients. The neurological functional recovery was assessed after operation by Japanese Orthopaedic Association (JOA) score. The range of motion of replaced segment and adjacent segments was measured (Cobb angle), and Kellgren’s X-ray assessment was used to evaluate the degree of adjacent segment degeneration. Results The operation was successfully performed in all cases, with primary heal ing of all the incisions. All patients were followed up from 12 to 36 months with an average of 23.1 months. JOA score was significantly improved at last follow-up when compared with preoperative score (P lt; 0.05), and no significant difference was observed in the Cobb angle of replaced segment and adjacent segments between pre- and postoperation (P gt; 0.05). According to the Kellgren’s X-ray assessment, degeneration of the adjacent segments occurred in 5 cases at last follow-up, including 3 cases of degeneration from grade 0 to grade 1 or 2, 1 from grade 1 to grade 2, and 1 from grade 2 to grade 3, with a degeneration rate of 12.8%, but no significant difference was found in degeneration degree when compared with preoperative value (χ2=1.793，P=0.406). No degeneration of adjacent segments occurred in 32 patients at 15 months after operation. Conclusion Artificial disc replacement has a good effectiveness in treating cervical spondylosis, which can maintain the range of motion of the replaced segment and adjacent segments, and may have a protective effect on adjacent segment discs.
ObjectiveTo compare the effect on adjacent segment degeneration after cervical disc arthroplasty (CDA) and anterior cervical decompression and fusion (ACDF) for treatment of cervical spondylosis. MethodsBetween August 2009 and February 2012, 60 cases of single segmental cervical spondylosis accorded with the inclusion criteria were included. Of 60 patients, 28 patients underwent CDA (CDA group) and 32 patients underwent ACDF (ACDF group). There was no significant difference in gender, age, disease duration, pathological type, pathological segment, the time of conservation treatment, preoperative neck disability index (NDI), preoperative Japanese Orthopaedic Association (JOA) score, and degeneration of the adjacent segment and disc between 2 groups (P > 0.05). The NDI and JOA score were used to evaluate effectiveness. The range of motion (ROM) of adjacent segment was measured, and degeneration of the adjacent segment and disc was evaluated according to Kellgren grading system based on X-ray and Miyazaki grading system based on T2-weighted MRI, respectively. ResultsThe follow-up time was 24-50 months (mean, 34 months) in 2 groups. All patients had no complication of prosthesis loosening, dislocation, or fracture of plate. The NDI and JOA scores from 12 months after operation were significantly improved compared with preoperative scores in 2 groups (P < 0.05), but no significant difference was found at each time point between 2 groups (P > 0.05). The improvement rate of JOA was 80.68%±4.01% in ACDF group and was 79.44%±3.76% in CDA group at last follow-up, showing no significant difference (t=1.237, P=0.221). And the improvement rate of JOA in 2 groups were excellent. There was no significant difference in ROM and degeneration grading of adjacent segments between at last follow-up and at pre-operation in 2 groups (P > 0.05), and between 2 groups at pre-operation and at last follow-up (P > 0.05). The degeneration grading of disc at last follow-up showed significant difference in 2 groups compared with preoperative ones (P < 0.05), but no significant difference was found between 2 groups (Z=0.132, P=0.895). ConclusionBoth CDA and ACDF can achieve good effectiveness in treating cervical spondylosis, but CDA can not significantly slow down the degeneration of adjacent segment disc.
Anterior cervical decompression and fusion (ACDF) treatment for cervical spondylosis has been more than half a century, and achieved good clinical results. However, with the continuous extension of follow-up time, the fusion segment-associated postoperative complications emerged gradually. Reserved cervical stability and activity, the concept of non-fusion was born. As a non-fusion technique, cervical artificial disc replacement (CADR) developed rapidly. With the continuous development of artificial prosthesis materials and design concepts, and specification and proficiency of surgical procedures, CADR has achieved better short- and mid-term clinical efficacy than ACDF. Compared with ACDF, the main advantages of CADR are that the postoperative recovery is quick, the activity and stability of cervical vertebra are maintained, the height of cervical intervertebral space is restored, and the stress of adjacent segments and the rate of surgical renovation are reduced. In clinical work, as an emerging technology, CADR requires spine surgeons to control the surgical indications, contraindications, and patients’ conditions strictly. This article reviews the research progress of CADR in order to provide new ideas for clinical treatment of cervical spondylosis.
Objective To analyze the prospective effect of pre-existing spinal stenosis of adjacent segment on the short-term effectiveness after lumbar fusion surgery. Methods A prospective comparative study was conducted to divide 183 patients with L4-S1 lumbar spinal stenosis who met the selection criteria between July 2015 and December 2017 into two groups according to the status of adjacent segment degeneration (ASD) judged by preoperative disc degeneration and spinal stenosis. There were 98 patients in group A (no degeneration of adjacent segments before operation) and 85 patients in group B (adjacent segments degenerated before operation). There was no significant difference in gender, American Society of Anesthesiologists (ASA) grade, body mass index (BMI), combined spondylolisthesis, and preoperative visual analogue scale (VAS) score of low back pain and leg pain, Japanese Orthopaedic Association (JOA) score, and Oswestry disability index (ODI) score between the two groups (P>0.05); the age of group A was significantly younger than that of group B (t=−3.560, P=0.000). The operation time, intraoperative blood loss, hospitalization stay, and perioperative complications were recorded and compared. The VAS score of low back pain and leg pain, JOA score, and ODI score at last follow-up were used to evaluate the effectiveness. The incidence of ASD after operation was compared between the two groups, and logistic regression was used to analyze the independent risk factors affecting the occurrence of ASD after operation. Results There was no significant difference in operation time, intraoperative blood loss, and hospitalization stay between the two groups (P>0.05). The incidence of perioperative complications in groups A and B was 13.3% and 20.0%, respectively, with no significant difference (χ2=1.506, P=0.220). Two groups of patients were followed up, the follow-up time of groups A and B was (24.9±8.8) months and (24.8±7.8) months, respectively, there was no significant difference (t=0.050, P=0.960). At last follow-up, no adjacent segment disease was found in either group. There was no significant difference in Pfirrmann grade between the two groups at last follow-up (P>0.05), and there was significant difference in Pfirrmann grade between the two groups before operation and at last follow-up (P<0.001). At last follow-up, 21 cases (21.4%) in group A and 53 cases (62.4%) in group B had ASD, with significant difference (χ2=31.652, P=0.000). The main cause of ASD was the severity of adjacent spinal canal stenosis. The clinical scores of the two groups at last follow-up were significantly improved when compared with those before operation (P<0.05). The JOA score of group A was significantly higher than that of group B at last follow-up (P<0.05). In group B, the VAS score of low back pain and ODI score in patients with ASD after operation at last follow-up were significantly higher than those in patients without ASD (P<0.05). logistic regression analysis showed that preoperative pre-existing degeneration and BMI were independent risk factors for ASD after operation (P<0.05). Conclusion Pre-existing mild spinal stenosis in adjacent segment can significantly affect the effectiveness, and can significantly increase the risk of ASD early after operation. The main pathological type of ASD was the severity of adjacent segment spinal stenosis. For preoperative assessment of pre-existing degeneration, we should evaluate the overall degeneration of the adjacent segment of the spinal canal, rather than simply evaluating the degeneration of the adjacent disc and facet joints.