Rate Of Adjacent Segment Degeneration Research Articles

Can unilateral-transforaminal lumbar interbody fusion replace the traditional transforaminal lumbar interbody fusion procedure for lumbar degenerative disc diseases?: a single center matched case-control mid-term outcome study.

Matched case-control study. To evaluate the midterm outcomes of unilateral pedicle screw fixation (UPSF) versus bilateral pedicle screw fixation (BPSF) in transforaminal lumbar interbody fusion (TLIF) procedure, ascertain efficacy of UPSF in adequately decompressing contralateral foramen+spinal canal and reducing rate of adjacent segment degeneration (ASD) at 4-8-year follow-up (FU). Previous meta-analyses found no significant differences between UPSF and BPSF regarding fusion rates, clinical and radiological outcomes; however, few studies have reported higher rates of cage migration/subsidence and pseudoarthrosis in the UPSF. No study has evaluated the impact of UPSF on indirect decompression and ASD. Retrospective analysis of 319 patients treated with UPSF vs. 331 patients treated with BPSF between 2012 to 2020. Clinical and radiological outcomes were evaluated at 6 months, 1 year, 2 years, and 4 years postoperatively. X-rays were used to assess fusion+ASD and computed tomography scans in doubtful cases. Magnetic resonance imaging was used at last FU to determine cross-sectional area of cord (CSA), foraminal height (FH), and width (FW) restoration. The mean FU duration was 50 months (range, 44-140 months). In UPSF, CSA increased by 2.3 times from preoperative values; FH and FW increased by 25% and 17.5%, respectively, at last FU (p<0.001); fusion rate was 94.3%, comparable to BPSF (similar CSA, FW, FH, 96.4% fusion rate). In UPSF, adjacent disc height remained stable, from preoperative 11.39±2.03 to 10.97±1.93 postoperatively at 4 years and 10.03±1.88 at 8 years. BPSF showed ASD in 14 (4.47%) vs. three patients (1.06%) in UPSF (p<0.04). Complication rates were similar (6.58% UPSF vs. 6.04% BPSF, p>0.05). UPSF-TLIF is comparable to BPSF in terms of patient-reported clinical outcomes, fusion rates, and complication rates while being superior in terms of lesser ASD. UPSF enables radiologically and clinically significant contralateral indirect neural foraminal decompression and canal decompression without disturbing the contralateral side anatomy, unlike BPSF.

Comparing outcomes between anterior cervical disc replacement (ACDR) and minimally invasive posterior cervical foraminotomy (MI-PCF) in the treatment of cervical radiculopathy

BACKGROUND CONTEXTAnterior cervical disc replacement (ACDR) and minimally invasive posterior cervical foraminotomy (MI-PCF) have emerged as two increasingly popular alternatives to anterior cervical discectomy and fusion (ACDF) for the management of cervical radiculopathy. Both techniques provide advantages of segmental motion preservation and lower rates of adjacent segment degeneration (ASD) compared to ACDF. PURPOSEThe purpose of this study was to analyze the clinical and functional outcomes of patients undergoing ACDR or MI-PCF for the treatment of unilateral cervical radiculopathy. STUDY DESIGN/SETTINGRetrospective Cohort Review. PATIENT SAMPLEA total of 152 patients were included (86 ACDR and 66 MI-PCF). OUTCOME MEASURES(1) Patient demographics; (2) perioperative data; (3) rates of complications and revisions; (5) visual analogue scale (VAS) and Neck Disability Index (NDI) scores. METHODSA retrospective cohort review was performed to identify all patients at a single institution between 2012-2020 who underwent 1- or 2- level ACDR or MI-PCF from C3-C7 with a minimum follow-up of 24 months. Patient demographics, perioperative data, postoperative complications, and revisions were analyzed. Patient reported outcome measures including VAS and NDI scores were compared. RESULTSThe ACDR group had a significantly greater mean operative time (99.8 minutes vs 79.2 minutes, p<.001), but comparable estimated blood loss and length of stay following surgical intervention (p=.899). The overall complication rate was significantly greater in the ACDR group than the MI-PCF group (24.4% vs 6.2%; p=.003) but was largely driven by approach-related dysphagia in 20.9% of ACDR patients. The MI-PCF group had significantly greater revision rates (13.6% vs 1.2%; p=.002) with an average time to revision of 20.7 months in the MI-PCF group compared to 40.3 months in the ACDR group. The ACDR cohort had significantly greater improvements in NDI scores at the final follow-up (25.0 vs 21.3, p<.001). ConclusionOur results suggest that ACDR offer clinically relevant advantages over MI-PCF in terms of long-term revision rates despite an increased approach-related risk of transient postoperative dysphagia. Additionally, patients in the ACDR cohort achieved greater mean improvements in NDI scores but these results may have limited clinical significance due to inability to reach minimally clinically important difference (MCID) thresholds.

A comparative and prospective study of surgical outcomes of cervical artificial disc to anterior cervical discectomy and fusion in the treatment of symptomatic degenerative disc disease of cervical spine in a tertiary care center of Eastern India

Background: Cervical disc degeneration is known to be a primary cause of neck pain and neurologic symptoms and can cause significant morbidity. Degeneration can be related to radiculopathy or myelopathy due to compression of spinal nerves and/or spinal cord. Disc pathology may manifest clinically as localized and radicular pain, myelopathy, and spinal joint instability. If severe, such as in degenerative disc disease, infections, and trauma, surgical methods are indicated. Some studies reported that compared to anterior cervical discectomy and fusion (ACDF), cervical artificial disc (CAD) could provide better neurological outcomes and reduce the rate of adjacent segment degeneration, whereas other studies reported no difference between the two procedures. Aims and Objectives: The aim of this study was to compare surgical outcomes of CAD to anterior cervical discectomy and fusion in the treatment of symptomatic degenerative disc disease in cervical spine. Materials and Methods: It was a comparative study with prospective design conducted among 40 symptomatic cervical disc degenerative disease patients (20 patients undergoing CAD and the remaining 20 anterior cervical discectomy and fusion) at the Department of Neurosurgery, Bangur Institute of Neurosciences, 1PGMER and SSKM Hospital, Kolkata, from January 2021 to December 2022. Respective surgical procedures were done. All patients were required to return for follow-up. Clinical and radiological evaluations were performed at 1 month, 3 months, 1 year, postoperatively, and last follow-up (more than 18 months). Clinical effectiveness was evaluated by the visual analog scale (VAS) score, Japanese Orthopedic Association (JOA) score (17 points system, 1994 revised edition), and neck disability index (NDI) score. Results: Improvement in NDI, VAS, and JOA index was found to be more in CAD as compared to ACDF group with a statistically significant difference as P&lt;0.05. Subsequent surgical intervention was reported among four subjects, out of which one belonged to the CAD group while the rest three to ACDF. Overall success was found to be more in the CAD group (75%) as compared to the ACDF group (55%), though no significant difference was revealed as P&gt;0.05. Conclusion: The findings of the present study support the superior longevity and better outcome of CDA, as compared with ACDF, with regard to need for subsequent surgical intervention and also support better improvement in symptoms in subsequent follow-up in patients undergoing CDA as compared to ACDF despite having comparable mean operative time and blood loss.

Should patient eligibility criteria for cervical disc arthroplasty (CDA) be expanded? A retrospective cohort analysis of relatively contraindicated patients undergoing CDA

Background ContextCervical disc arthroplasty (CDA) is a safe and effective alternative to anterior cervical discectomy and fusion (ACDF) in the treatment of various degenerative pathologies with advantages of motion preservation and lower rates of adjacent segment degeneration (ASD). Absolute contraindications for CDA have been well outlined in order to prevent adverse outcomes in patients. However, in cases of patients with relative contraindications (kyphotic deformity, prior cervical surgery, etc.), there remains controversy. There is minimal literature evaluating long-term outcomes in this patient population. PurposeTo compare long-term clinical and functional outcomes of CDA in typical patients versus those with relative contraindications. DesignRetrospective cohort review. Patient SampleEighty-nine patients were included in the study: 55 (no contraindications) in Group 1 and 34 (relatively contraindicated) in Group 2 and 26 (preoperative segmental kyphosis) in Group 3. Outcome Measures(1) Patient demographics; (2) perioperative data; (3) rates of complications and revisions; (5) visual analogue scale (VAS), and neck disability index (NDI) scores. MethodsPatients were placed in the relatively contraindicated cohort if they possessed at least one of the following: (1) segmental kyphosis of 5° to 10°, (2) significant loss of disc height (between 50% and 75% of initial measurements or 1.5–3mm), (3) bridging osteophytes, and (4) prior cervical spine surgery based on preoperative cervical radiographs. The other cohort included patients without any relative contraindication who underwent CDA over the same time frame. Additionally, a subgroup analysis was used to compare those without any contraindications to those with only preoperative segmental kyphosis. Patients were included in this study if they met the following criteria: over 18 years of age, minimum follow-up of 24 months, and availability of complete medical records. Patient demographics, levels operated on, and perioperative outcomes were assessed between the two groups. Revision and complication rates were recorded. Functional outcomes scores were compared using VAS and NDI scores at 6-months, 12-months and final follow-up. ResultsMean follow-up was 40.8 months in Group 1 and 38.3 months in Group 2 (p=.569). Complication rates were 21.8% in Group 1 and 26.4% in Group 2 (p=.615). Complication rates in a comparison between Groups 1 and 3 were statistically insignificant (p=.383). The most common complication was transient approach-related postoperative dysphagia (Group 1: 20% vs Group 2: 23.5%, p=.693). No significant differences were observed in the rates of transient dysphonia (Group 1: 0.0% vs Group 2: 2.9%, p=.201), adjacent segment degeneration (ASD) (Group 1: 1.8% vs Group 2: 0.0%, p=.429), infection (Group 1: 1.8% vs Group 2: 2.9%, p=.712), heterotopic ossification (Group 1: 49.1% vs Group 2: 50.0%, p=.934) or spontaneous fusion (Group 1: 1.8% vs Group 2: 2.9%, p=.728). No revision surgeries were observed in either cohort. All three groups demonstrated significant improvements in their VAS and NDI scores compared with preoperative measurements (p<.001), but no significant differences were found in the degree of improvement between groups at any point in time. ConclusionsOur study found no significant differences in clinical and functional outcomes between patients undergoing 1- and 2-level CDA with relative contraindications versus typical patients. These findings suggest that patient eligibility criteria for CDA may warrant expansion. However, future prospective studies over a longer period of follow-up are necessary to corroborate our results.

Mechanical properties of an elastically deformable cervical spine implant

Anterior cervical surgery is widely accepted and time-tested surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the high adjacent segment degeneration rate and implant subsidence after the surgery using the traditional polyetheretherketone cage. Thus, we creatively designed a polyurethane cervical implant that can continuous load-sharing through elastic deformation and decrease postoperative stress concentration at adjacent segments. In this study, the design rationality and safety of this novel implant was evaluated based on several mechanical parameters including compression test, creeping test, push-out test and subsidence test. The results showed that the novel cervical implant remained intact under the compressive axial load of 8000 N and continues to maintained the elastic deformation phase. The minimum push-out load of the implant was 181.17 N, which was significantly higher than the maximum compressive shear load of 20 N experienced by a normal human cervical intervertebral disc. Besides, the creep recovery behaviour of the implant closely resembled what has been reported for natural intervertebral discs and clinically applied cervical devices in literature. Under the load of simulating daily activities of the cervical spine, the implant longitudinal displacement was only 0.54 mm. In conclusion, this study showed that the current design of the elastically deformable implant was reasonable and stable to fulfil the mechanical requirements of a cervical prosthesis under physiological loads. After a more comprehensive understanding of bone formation and stress distribution after implantation, this cervical implant is promising to be applied to certain patients in clinical practice.

Hybrid fixation versus conventional cage-plate construct in 3-level ACDF: Introduce the “seesaw theory” of stand-alone cage

Study designA retrospective study. BackgroundConventional cage-plate construct (CCP) was widely used in anterior cervical discectomy and fusion (ACDF), but the rigid fixation limits the motion of fused segments. Self-locking stand-alone cage (SSC) was an alternative for ACDF procedures and showed several superiorities. However, the effect of hybrid fixation in 3-level ACDF remains unknown. ObjectiveTo assess the clinical and radiological outcomes of hybrid fixation with SSC and CCP against conventional CCP in 3-level ACDF. MethodA retrospective review of patients who underwent 3-level ACDF at Renji Hospital between January 2018 and December 2019 was performed. Eighty-three patients met the inclusion and exclusion criteria and were stratified into 2 groups based on the fixation methods. The clinical outcomes, functional outcomes, and radiological parameters were collected and analyzed. ResultsNo significant difference was observed between the two groups in the mean age, sex, body mass index, hospital stay, and duration of follow-up. The postoperative C2–7 Cobb angle in the CCP group was significantly greater than that in the hybrid group. The rate of cervical proximal junctional kyphosis (CPJK) in the hybrid group was significantly lower than that in the CCP group. The CCP group suffered significantly higher rates of adjacent segment degeneration (ASD) than the hybrid group at 2 years postoperatively. Moreover, the incidence of postoperative dysphagia was lower in the hybrid group. No significant differences were observed in JOA and NDI scores between the two groups. ConclusionThe hybrid fixation achieved comparable clinical outcomes against CCP fixation, indicating that hybrid fixation is an alternative procedure in 3-level ACDF.

Clinical and imaging outcomes of self-locking stand-alone cages and anterior cage-with-plate in three-level anterior cervical discectomy and fusion: a retrospective comparative study

BackgroundAnterior cervical discectomy and fusion has been considered standard management for cervical myelopathy and radiculopathy. However, the option of using self-locking stand-alone cages or cage-with-plate in three-level anterior cervical discectomy and fusion still remains controversial. The aim of this study was to evaluate the clinical and imaging outcomes of the two procedures in multilevel anterior cervical discectomy and fusion.MethodsSixty-seven patients who underwent three-level anterior cervical discectomy and fusion were enrolled in this study, of which 31 patients underwent surgery using self-locking stand-alone cages (group cage) and 36 patients using cage-with-plate (group plate). For the evaluation of clinical outcomes, modified Japanese Orthopedic Association scores, visual analogue scale for neck pain, neck disability index, Odom’s criteria and dysphagia status were measured. Imaging outcomes were evaluated by cervical sagittal angle, fusion segmental Cobb’s angle, fusion segmental height, range of motion, cage subsidence rate, fusion rate and adjacent segment degeneration. Statistical analyses were performed using the SPSS software (version 19.0).ResultsBoth groups showed improvement in modified Japanese Orthopedic Association scores, visual analogue scale for neck pain and neck disability index, after surgery, and there was no significant difference between the groups. The occurrence rate of dysphagia is significantly lower in the group cage compared with the group plate (p < 0.05). The postoperative cervical sagittal angle, fusion segmental Cobb’s angle, fusion segmental height and cage subsidence rate in the group plate were significantly superior to that in the group cage (p < 0.05). However, the rate of adjacent segment degeneration was significantly lower in the group cage compared with the group plate (p < 0.05). Both groups showed no significant difference in terms of fusion rate (p > 0.05).ConclusionsThe self-locking stand-alone cages are effective, reliable and safe in anterior cervical discectomy and fusion for the treatment of cervical myelopathy and radiculopathy. Self-locking stand-alone cages showed a significantly lower rate of dysphagia and adjacent segment degeneration, while anterior cervical cage-with-plate could provide stronger postoperative stability and maintain better cervical spine alignment.

A comparison of three bone graft struts for interbody fusion using a posterior approach for lower lumbar spinal tuberculosis in adults: a midterm follow-up study

BackgroundThis retrospective observational study was conducted to compare midterm outcomes of three bone graft struts for interbody fusion using a posterior approach in adults with lower lumbar spinal tuberculosis.MethodsA total of 126 lower lumbar spinal tuberculosis patients were treated by one-stage posterior debridement, interbody fusion, and instrumentation. Forty-one patients (group A) were treated with autogenous bone graft for interbody fusion, 45 patients (group B) were treated with allogeneic bone grafting, and the remaining 40 (group C) patients were treated with titanium mesh cage. In addition, clinical and radiographic data were gathered and analyzed.ResultsAt the final follow-up, all patients were completely cured. The operation period and intraoperative blood loss for groups B and C were significantly less than in group A (P = 0.000). Post-operation, neurological performance and quality of life were remarkably improved at the final follow-up. The preoperative lordosis angles of three groups were significantly improved, as evidenced by the values immediately after the operation or those at the final follow-up. The correction loss of the group C was lower than those of groups A and B (P = 0.000). All the patients obtained bone graft fusion, the fusion period of group B was longer than that of the other two groups (P = 0.000). No significant differences among the three groups in adjacent segment degeneration rates were found at the last visit (P = 0.922).ConclusionsThis midterm follow-up study established that one-stage posterior debridement, interbody fusion, and instrumentation, combined with medical therapy, can effectively treat lower lumbar spinal tuberculosis. In addition, the intervertebral titanium mesh cage bone graft can provide better outcomes with regard to maintaining lordosis and preventing collapse.

Efficacy of the Dynesys Hybrid Surgery for Patients with Multi-Segmental Lumbar Spinal Stenosis.

ObjectiveThe efficacy of hybrid (Dynesys and fusion) surgery and the traditional transforaminal lumbar interbody fusion surgery was compared in patients with multi-segmental lumbar spinal stenosis.MethodsA total of 68 patients with multi-segmental lumbar spinal stenosis subjected to surgery were recruited between January 2013 and October 2020 in the First Affiliated Hospital of Southern University of Science and Technology. The patients were divided into a hybrid group (N = 33) and a TLIF group (N = 35) by surgery. After surgery, follow-up was conducted for 12 months. Between the two groups, the following parameters were compared: general conditions, clinical symptom scores, imaging parameters, and early complications.ResultsA statistically significant difference in the duration of surgery was noted between the two groups. After 12 months of follow-up, the range of motion disappeared in the TLIF group, while 63.53% was preserved in the hybrid group with statistically significant differences. A statistically significant difference was identified in the Oswestry Disability Index one week after surgery. Nonetheless, no statistically significant differences were observed at the 12-month post-surgical follow-up. Pfirrmann grade showed a 3.03% upper adjacent segment degeneration rate in the hybrid group (1/33) at 12-month follow-up and 2.86% (1/35) in the TLIF group. Notably, no early complications (screw loosening and wound infection) were identified in the two groups.ConclusionThe Dynesys hybrid surgery combined the advantages of two systems of dynamic stabilization and rigid fusion. Besides, hybrid surgery is potentially a novel approach for the treatment of multi-segmental lumbar spinal stenosis.

The Incidence of Adjacent Segment Pathology After Cervical Disc Arthroplasty Compared with Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

The aim of this study was to assess rates of adjacent segment degeneration (ASDeg), adjacent segment disease (ASDis), and reoperation rates as a result of adjacent segment pathology in patients who have undergone anterior cervical discectomy and fusion (ACDF) versus cervical disc arthroplasty (CDA). A comprehensive search of randomized controlled trials was performed in PubMed from 2012 to 2019. Relevant studies included were assessed for quality using the Cochrane Beck Review Group guidelines. Rates of ASDeg, ASDis, and reoperation because of adjacent segment pathology were extracted and included in the final analysis. A random-effects and fixed-effects model was run among studies that showed high and low heterogeneity, respectively. A total of 19 studies were included in the final analysis, comprising 4655 patients. Overall, ACDFs reported significantly higher rates of ASDeg (19.7% vs. 14.4%; P < 0.001), ASDis (6.1% vs. 3.8%; P < 0.001), and reoperation rates (6.1% vs. 3.1%; P < 0.001) compared with CDAs, which was further corroborated in fixed-effects analysis. When stratified by length of follow-up, a significant difference was seen in ASDeg, ASDis, and reoperation rates of studies with follow-up of 12-48 months versus >48 months, with the exception of ASDeg rates in the CDA cohort. Our study shows CDA results in significantly lower ASDeg, ASDis, and reoperation rates. Although CDA may be a viable alternative to ACDF, further long-term studies are warranted to ensure consistency and establish longevity of our findings.

Can Indirect Decompression Reduce Adjacent Segment Degeneration and the Associated Reoperation Rate After Lumbar Interbody Fusion? A Systemic Review and Meta-analysis

We sought to assess and compare the rate of adjacent segment degeneration (ASDeg), adjacent segment disease, and related reoperations between patients who underwent lumbar interbody fusion surgery using indirect or direct decompression. On the basis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review and meta-analysis was performed to identify and analyze studies that compared the rate of ASDeg, adjacent segment disease, and related reoperations between indirect and direct decompression techniques. Indirect decompression included anterior lumbar interbody fusion, lateral lumbar interbody fusion, and oblique lateral interbody fusion, whereas direct decompression included posterior or transforaminal lumbar interbody fusion. Seven studies including a total of 576 patients (indirect: 314; direct: 262) were identified. The pooled rates of ASDeg were 19.4% (45/232) and 34.9% (66/189) for indirect and direct decompression, respectively. A fixed-effects model showed 0.34 times lower odds of developing ASDeg in the indirect decompression group (odds ratio= 0.34, 95% confidence interval [CI]= 0.20, 0.57). The pooled incidence of reoperation was 2.5% (8/314) and 6.1% (16/262) for indirect and direct decompression, respectively. A fixed-effects model showed 0.40 times lower odds of reoperation fromASDeg in the indirect decompression group (odds ratio= 0.40, 95% CI= 0.18, 0.89). The pooled mean difference for the segmental lordosis angle was 1.80 degrees (95% CI=0.74, 2.86) and 7.11 degrees (95% CI= 4.47, 9.74) for total lumbar lordosis angle, favoring indirect decompression. Indirect decompression showed lower odds of developing ASDeg and undergoing reoperation for ASDeg after lumbar interbody fusion surgery in this meta-analysis. However, the limited number and quality of the included studies should be considered when interpreting the results.

Spondylolisthesis at L4/5 but Fixation of L4, L5 and S1 Reduces the Rate of Adjacent Segment Degeneration

Study background: Adjacent segment disease (ASD) is a common phenomenon seen in patients who have undergone prior lumbar fusion surgery is characterized by degeneration and/or stenosis. Treatment for ASD includes extension of the fusion with a posterior approach, with direct decompression of the neural elements when indicated. Methods: 54 patients of spondylolisthesis involving L4/5 level were included in this study that were operated from January 2012 to December 2020 in Bangabandhu Sheikh Mujib Medical University and few private hospital in Dhaka who failed to respond in conservative treatment. 30 patients were male and 24 were female. patients were evaluated by clinical finding (low back pain, sensory, motor and jerks) VAS score, ODI score, JOA score, modified Macnab’s criteria, claudication distance, X-ray lumbosacral spine AP and lateral view, MRI of lumbosacral spine, CT scan of lumbosacral spine. P value of less than 0.05 was level significance. Results: Mean (± SD) age of the patients was 56.29 ± 8.13 with highest age being 68 years and lowest being 41 years. 40 were male and 24 were female. Preoperative VAS score (for both back pain and leg pain) was 6.86 ± 0.65 which significantly reduced to 1.04 ± 0.19 36 months after operation. Out of 64 patients, 62 patients showed interbody fusion with good trabecular marking. Postoperative MRI of lumbosacral spine at 36 months showed 48 patients out of 64 had no desiccation of L3/4 disc, 9 had mild disc desiccation and 7 developed desiccation of L3/4 disc. Final outcome was determined by Modified Macnab’s criteria. Excellent result found in 39 patients, good result found in 22 patients and fair result found in 3 patients. Conclusion: Fixation of L4, L5 along with S1 in single level PLIF or TLIF in L4/5 level significantly reduce the rate of disc degeneration at L5/S1 level with slight degeneration at L3/4 level.

78. The current incidence of adjacent segment pathology following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF): a systematic review and meta-analysis of randomized clinical trials

BACKGROUND CONTEXT The introduction of CDA has provided a biomechanically sound alternative to ACDF, helping to preserve motion and potentially reduce adjacent segment pathology. To date, studies have shown conflicting results on the true impact of ACDF and CDA on adjacent levels. PURPOSE To assess rates of radiographic adjacent segment degeneration (ASDeg) and symptomatic adjacent segment disease (ASDis), as well as reoperation rates due to adjacent segment pathology in patients who have undergone anterior cervical discectomy and fusion (ACDF) vs cervical disc arthroplasty (CDA). STUDY DESIGN/SETTING Meta-analysis of randomized controlled trials (RCTs). PATIENT SAMPLE A total of 18 studies were included in the final analysis, comprising 4,082 total patients with 1,854 patients who underwent ACDF and 2,454 who underwent CDA. OUTCOME MEASURES The pooled outcomes of interest included: adjacent segment degeneration, adjacent segment disease and reoperation for adjacent segment pathology. Adjacent segment degeneration was defined as changes on plain radiographs or magnetic resonance imaging (MRI) at segments adjacent to a previously operated level. Adjacent segment disease or symptomatic adjacent segment pathology was defined by persistent neck pain and new-onset radiculopathy/myelopathy. Symptomatic adjacent segment pathology requiring additional surgical intervention was categorized as reoperation due to adjacent segment pathology. METHODS A comprehensive search of RCTs was performed in PubMed from 2012 to 2019. Relevant studies included were assessed for quality using the Cochrane Beck Review Group guidelines. Rates of ASDeg, ASDis, and reoperation due to adjacent segment pathology were extracted and included in the final analysis. RESULTS Overall, ACDFs compared to CDAs had higher rates of radiographic adjacent segment degeneration (45.26% vs 31.91%), symptomatic ASDis (16.21% vs 10.96%), and reoperation (8.53% vs 5.26%, respectively; all p CONCLUSIONS Currently, CDA has lower rates of adjacent segment degeneration, disease, and reoperation rates compared to ACDF in those with at least 2 years follow-up. CDA may be a viable alternative to ACDF; however, further long-term studies are warranted to ensure consistency and establish longevity of our findings. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

18. Fatty infiltration of the lumbar multifidus (LM) may be associated with adjacent segment degeneration after fusion for spondylolisthesis

BACKGROUND CONTEXT Paraspinal muscle fat infiltration has been shown to be associated with back pain. However, it is unclear if fat infiltration of the lumbar multifidus (LM) increases the rate of adjacent segment degeneration after fusion. PURPOSE To investigate if fatty infiltration of LM is associated with adjacent segment degeneration after L4-5 transforaminal lumbar interbody lumbar fusion (TLIF) for spondylolisthesis. STUDY DESIGN/SETTING Retrospective study. PATIENT SAMPLE Single academic center with degenerative spondylolisthesis patients undergoing L4-5 TLIF. OUTCOME MEASURES Radiographic measures included: pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL) and PI-LL. Fat infiltration (L3, L4 and L5) was measured with Goutallier classification on preop MRI. METHODS A total of 178 patients undergoing L4-5 TLIF for spondylolisthesis (2006 to 2016) were retrospectively analyzed. Inclusion criteria were: minimum 2-year follow-up, preop MRI and preop X-rays, L4-5 TLIF. Twenty-three patients underwent revision surgery for adjacent segment degeneration during the follow-up. Another 23 patients without adjacent segment degeneration were collected to match the patients with adjacent segment degeneration. RESULTS A total of 46 patients were evaluated (18 males, mean age 61years). The average follow-up was 40 months. There was no difference in age, sex, BMI and spinopelvic parameters with regard to the patients with and without adjacent segment disease (p>0.05). Fatty infiltration of LM was more significant in the patients with adjacent segment disease than those in the patients without adjacent segment disease (p=0.029). The fatty infiltration was most significant at L3 in patients with adjacent segment disease compared to patients without ASD (p=0.017). At L4 and L5, there was an increasing trend of fatty infiltration in the patients with adjacent segment disease compared to patients without adjacent segment disease, but the difference was not statistically significant (p>0.05) CONCLUSIONS In patients who underwent revision surgery for adjacent segment disease, fatty infiltration of LM was more significant compared to patients without adjacent segment disease. Fatty infiltration of LM may be associated with adjacent segment disease after fusion. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Is Anterior Bone Loss the Opposite of Anterior Heterotopic Ossification in Prestige-LP Cervical Disc Replacement?

Heterotopic ossification (HO) and anterior bone loss (ABL) are 2 complications in cervical disc replacement (CDR), which have impacts on the clinical outcomes. Physiologically, bone formation (HO) and bone loss are 2 sides of bone remodeling. However, clinically, some patients experienced anterior HO (AHO) after CDR, whereas other patients experienced ABL. Is there any factor in determining the fate of the vertebral bone in the anterior region? Is ABL the opposite of AHO? This study aims to answer these questions. Seventy patients with 1-level Prestige-LP CDR were retrospectively reviewed and were divided into an AHO group or ABL group. Radiologic outcomes, including cervical lordosis, sagittal vertical axis, functional spine unit angle, disc angle, range of motion, implant migration, subsidence, and adjacent segment degeneration were evaluated. Patient-reported clinical outcomes were also evaluated. AHO group showed significantly lower disc angle after surgery (0.9° ± 4.2°), compared with ABL group (6.7° ± 4.7°) (P < 0.001). The preoperative segmental range of motion was significantly higher in the AHO group (10.2° ± 3.3°) than in the ABL group (8.2° ± 3.7°) (P= 0.042). No correlation was observed between clinical outcomes and the presence of anterior bone remodeling. Both groups maintained cervical alignment and functional spine unit angle during long-term follow-up. No significant difference was found in the end plate preparation, implant subsidence, migration, or adjacent segment degeneration rate between the 2 groups. The differences in the disc angle showed the role of mechanical load in the anterior bone remodeling. Combined the results with the basic concepts of bone remodeling, ABL may be the opposite of AHO.

The future of disc surgery and regeneration.

Low back and neck pain are among the top contributors for years lived with disability, causing patients to seek substantial non-operative and operative care. Intervertebral disc herniation is one of the most common spinal pathologies leading to low back pain. Patient comorbidities and other risk factors contribute to the onset and magnitude of disc herniation. Spine fusions have been the treatment of choice for disc herniation, due to the conflicting evidence on conservative treatments. However, re-operation and costs have been among the main challenges. Novel technologies including cage surface modifications, biologics, and 3D printing hold a great promise. Artificial disc replacement has demonstrated reduced rates of adjacent segment degeneration, need for additional surgery, and better outcomes. Non-invasive biological approaches are focused on cell-based therapies, with data primarily from preclinical settings. High-quality comparative studies are needed to evaluate the efficacy and safety of novel technologies and biological therapies.

Cervical disc herniation: which surgery?

Cervical disc herniation is a common pathology. It can be treated by different surgical procedures. We aimed to list and analyzed every available surgical option. We focused on the comparison between anterior cervical decompression and fusion and cervical disc arthroplasty. The anterior approach is the most commonly used to achieve decompression and fusion by the mean of autograft or cage that could also be combined with anterior plating. Anterior procedures without fusion have shown good outcomes but are limited by post-operative cervicalgia and kyphotic events. Posterior cervical foraminotomy achieved good outcomes but is not appropriate in a case of a central hernia or ossification of the posterior ligament. Cervical disc arthroplasty is described to decrease the rate of adjacent segment degeneration. It became very popular during the last decades with numerous studies with different implant device showing encouraging results but it has not proved its superiority to anterior cervical decompression and fusion. Anterior bone loss and heterotopic ossification are still to be investigated. Anterior cervical decompression and fusion remain the gold standard for surgical treatment of cervical disc herniation.

Multi- versus single-level anterior cervical discectomy and fusion: comparing sagittal alignment, early adjacent segment degeneration, and clinical outcomes

The purpose of this study was to compare the rates of adjacent segment degeneration (ASD), sagittal alignment parameters, and patient-reported outcomes in patients who underwent multi-level versus single-level anterior cervical discectomy and fusion (ACDF). A retrospective cohort analysis was performed on consecutive patients who underwent an ACDF. Pre- and post-operative radiographic assessment included ASD, change in C2-C7 lordosis, T1 angle, levels fused, sagittal vertical axis (SVA), fusion mass lordosis, proximal and distal adjacent segment lordosis. Patient-reported outcomes were obtained. Of the 404 that underwent an ACDF with a minimum of 6 months of follow-up (average 28 months), there was no significant difference in the rate of radiographic ASD overall (p=0.479) or in the proximal or distal adjacent segments on multivariate analysis. Secondarily, the multi-level fusions appear to restore significantly greater amounts of lordosis compared to single-level procedures (p<0.001) and are able to maintain the corrected cervical lordosis and fusion segment lordosis over time. From the immediate post-operative period to final follow-up, the single-level ACDFs show continuing lordosis improvement (p=0.005) that is significantly greater than that of the multi-level constructs. There were no significant differences between pre-operative, post-operative, or change in patient-reported outcomes. Two years following an ACDF, patients who underwent multi-level fusions appear to restore significantly greater amounts of lordosis compared to single-level procedures, while single-level ACDFs show significantly greater amounts of lordosis improvement over time. Multi-level procedures may not be at a significantly greater risk of developing early radiographic evidence of ASD compared to single-level procedure. These slides can be retrieved under Electronic Supplementary Material.

A Comprehensive Meta-Analysis of the Adjacent Segment Parameters in Cervical Disk Arthroplasty Versus Anterior Cervical Discectomy and Fusion.

This is a meta-analysis of controlled trials. To assess the overall condition of adjacent segment of cervical disk arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF). With the increase in CDA and ACDF, surgeons are taking more attention to adjacent segment degeneration (ASDeg) and adjacent segment disease (ASDis). There are more and more meta-analyses comparing the efficacy of CDA with ACDF, however, there are few meta-analyses referring to adjacent segment parameters, and investigators are still unable to arrive at the same conclusion. Several important databases were searched for controlled trials comparing CDA and ACDF before February 2016 according to PRISMA guidelines. The analysis parameters included follow-up time, operative segments, cervical range of motion (ROM), adjacent segment motion, ASDeg, ASDis and adjacent segment reoperation. The risk of bias scale and Newcastle-Ottawa Scale were used to assess the papers. Subgroup analysis and sensitivity analysis were used to analyze the reason for high heterogeneity. Forty-one controlled trials fulfilled the inclusion criteria, including 36 English papers and 5 Chinese. The average follow-up time of all included patients was 39 months. Compared with ACDF, the rate of adjacent segment reoperation in the CDA group was significantly lower (P<0.01), and the advantage of CDA group increased with the increasing of follow-up time according to subgroup analysis. The rate of ASDeg in CDA was significantly lower than that of ACDF (P<0.01). There was no statistical difference between upper and lower ASDeg using the same surgical method (P>0.05). CDA provided a greater cervical ROM than did ACDF (P<0.01). There was a lower adjacent segment ROM and the rate of ASDis in CDA compared with ACDF (P<0.05). Compared with ACDF, the advantages of CDA were lower ASDeg, ASDis, adjacent segment reoperation and adjacent segment motion; and higher cervical ROM. However, there was no statistical difference between upper and lower adjacent segment ROM/ASDeg using the same surgery.

Clinical and radiological outcome at 10 years of follow-up after total cervical disc replacement

PurposePrevious studies have demonstrated that total cervical disc replacement (cTDR) represents a viable treatment alternative to the ‘gold standard’ anterior cervical discectomy and fusion for the treatment of well-defined cervical pathologies at short- and mid-term follow-up (FU). However, the implementation and acceptance of a non-fusion philosophy is closely associated with its avoidance of adjacent segment degeneration. Proof of the functional sustainability and clinical improvement of symptoms at long-term FU is still pending. The aim of this ongoing prospective study was to investigate the clinical and radiological results of cTDR at long-term FU.Methods50 patients were treated surgically within a non-randomised prospective study framework with cTDR (ProDisc C™, Synthes, Paoli, PA, USA). Patients were examined preoperatively followed by routine clinical and radiological examinations at 1, 5 and 10 years after surgery, respectively. In addition to the clinical scores, conventional X-ray images of the cervical spine were taken in anteroposterior and lateral view as well as flexion/extension images. Clinical outcome scores included parameters such as the Neck Disability Index (NDI), Visual Analogue Scale (VAS), arm and neck pain self-assessment questionnaires as well as subjective patient satisfaction rates. The radiological outcome variables included the range of motion (ROM) of the implanted prosthesis between maximum flexion and extension images, the occurrence of heterotopic ossifications and radiographic signs of adjacent segment degenerative changes. The reoperation rate following cTDR was recorded as a secondary outcome variable.ResultsA significant and maintained clinical improvement of all clinical outcome scores was observed after a mean FU of 10.2 years (VASarm 6.3–2.1; VASneck 6.4–1.9; NDI 21–6; p < 0.05). An increase in the incidence and the extent of heterotopic ossifications was noted during the post-operative course with a significant influence on the function of the prosthesis, which, however, did not reveal any detrimental effect on the patients’ clinical symptomatology. Prosthesis mobility declined from 9.0° preoperatively and 9.1° at 1 year FU to 7.7° and 7.6° at the five- and ten-year FU examinations, respectively. Radiological signs of adjacent segment degeneration were detected in 13/38 (35.7%), however, in only 3/38 (7.9%) patients this radiological changes were associated with clinical symptoms requiring conservative treatment. Intraoperative technical failure in two cases required interbody fusion with a cage (2/50). One patient (1/48, 2.1%) treated this motion device had revision surgery at the index level.ConclusionCervical total disc replacement with ProDisc C demonstrated a significant and maintained improvement of all clinical outcome parameters at a follow-up of ≥10 years. The present long-term data reveal that with an exceptionally low implant-related reoperation rate and low symptomatic adjacent segment degeneration rate, cTDR may be regarded as a safe and viable treatment option.