Adjacent Segment Disease Research Articles

Effect of adjacent segmental facet joint degeneration on adjacent segment disease after lumbar fusion and fixation

To explore the effect of facet joint degeneration in adjacent segments on the incidence of adjacent segment disease (ASD) after lumbar fusion and fixation. A retrospective analysis was performed on 138 patients who underwent L5S1 posterior lumbar interbody fusion (PLIF) from June 2016 to June 2019. Patients were divided into a degeneration group (68 cases) and a non-degenerative group (70 cases) based on the presence or absence of L4,5 facet joint degeneration before surgery (graded using the Weishaupt standard). Age, gender, body mass index (BMI), follow-up time, and preoperative L4,5 intervertebral disc degeneration (graded using the Pfirrmann standard) were collected for both groups. Clinical outcomes were evaluated using the visual analogue scale (VAS) and Oswestry disability index (ODI) at 1 and 3 months after surgery. The incidence and time of ASD after surgery were analyzed. There were no significant differences between the two groups in age, gender, BMI, follow-up time, or preoperative L4,5 intervertebral disc degeneration. Both groups showed significant improvement in VAS and ODI at 1 and 3 months after surgery (P<0.001), with no significant difference between the groups(P>0.05). However, there was a statistically significant difference in the incidence and timing of ASD between the groups (P<0.05). The degeneration group had 2 cases of ASD in gradeⅠdegeneration, 4 cases of ASD in gradeⅡdegeneration, and 7 cases of ASD in grade Ⅲ degeneration. There was a statistically significant difference between the number of patients with grade Ⅲ degeneration and those with gradesⅠandⅡASD (P<0.0167, Bonferroni correction). Preoperative degeneration of adjacent articular processes will increase the risk of ASD after lumbar fusion fixation, whereas gradeⅢ degeneration will further increase the risk.

Long-Term Changes in Sagittal Balance After Microsurgical Decompression of Lumbar Spinal Canal Stenosis in Elderly Patients: A Follow-Up Study for 5-Years After Surgery

The purpose of this study is to investigate long-term changes in spinal sagittal balance after microsurgical decompression in lumbar canal stenosis (LCS). Fifty-two patients who underwent microsurgical decompression for symptomatic single level L4/5 spinal canal stenosis at our hospital were included in the study. All patients had standing full spine radiographs taken preoperatively, 1year postoperatively, and 5years postoperatively. Spinal parameters including sagittal balance were measured from the obtained images. First, preoperative parameters were compared with 50 age-matched asymptomatic volunteers. Next, the parameters before and after surgery were compared to examine long-term changes. Sagittal vertical axis (SVA) was significantly increased in the LCS cases compared to the volunteers (P= 0.03). Postoperative lumbar lordosis (LL) was significantly increased (P= 0.03). Postoperative mean SVA decreased but the difference was not significant (P= 0.12). Although there was no correlation between preoperative parameters and the Japanese Orthopedic Association score, postoperative pelvic incidence (PI)-LL and pelvic tilt changes correlated with changes in Japanese Orthopedic Association score (PI-LL; P= 0.0001, pelvic tilt; P= 0.04). However, after 5years of surgery, LL decreased and PI-LL increased (LL; P= 0.08, PI-LL; P= 0.03). Sagittal balance began to deteriorate but was not significant (P= 0.31). At 5years postoperatively, 18 of 52 patients (34.6%) were found to have L3/4 adjacent segment disease. Cases with adjacent segment disease showed significantly worse SVA and PI-LL (SVA; P= 0.01, PI-LL; P < 0.01). In LCS, lumbar kyphosis improves and sagittal balance tends to improve after microsurgical decompression. However, after 5years, adjacent intervertebral degeneration occurs more frequently and sagittal balance begins to deteriorate in about one third of cases.

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis

Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH. This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF). A pure moment with a compressive follower load was applied to these models. ROM of L5-S and L4-S PLIF models decreased by more than 50% at L4-L5, respectively, and decreased by more than 15% at L1-S compared with the DISH model in all motions. The L4-L5 nucleus stress of the L5-S PLIF increased by more than 14% compared with the DISH model. In all motions, the hip stress of DISH, L5-S, and L4-S PLIF had very small differences. The sacroiliac joint stress of L5-S and L4-S PLIF models decreased by more than 15% compared with the DISH model. The stress values of the screws and rods in the L4-S PLIF model was higher than in the L5-S PLIF model. The concentration of stress because of DISH may influence adjacent segment disease on the nonunited segment of PLIF. A shorter-level lumbar interbody fixation is recommended to preserve ROM; however, it should be used with caution because it could provoke adjacent segment disease.

Commentary: Risk Factors for Adjacent Segment Disease in Short Segment Lumbar Interbody Fusion-A Case Series.

Chanbour, Hani MD*; Younus, Iyan MD*; Zuckerman, Scott L. MD, MPH*,‡ Author Information

Application of the oblique lateral interbody fusion technique in salvage surgery: technical note and case series.

The oblique lateral interbody fusion (OLIF) technique is a promising interbody fusion technique. This study summarizes the technical aspects of OLIF as a salvage surgery and the preliminary outcomes of a series of cases. A retrospective review of patients with leg or back pain induced by pseudoarthrosis or adjacent segment disease after posterior lumbar interbody fusion/transforaminal lumbar interbody fusion was done. These patients underwent salvage OLIF surgeries in our institution from January 2021 to March 2022. Variables such as the demographic, clinical, surgical, and radiological characteristics of the enrolled patients were recorded and analyzed. Eight patients (five females and three males; mean age 69.1 ± 5.7 years, range 63-80 years) were enrolled in this study. The mean operative time was 286.25 min (range: 230-440 min), and the estimated blood loss was 90 ml (range: 50-150 ml). Only one of the eight patients experienced a complication of lower limb motor weakness, which disappeared within 5 days after surgery. The latest data showed that the mean intervertebral space height increased from 8.36 mm preoperatively to 12.70 mm and the mean segmentary lordosis increased from 8.92° preoperatively to 15.05°. Bone fusion was achieved in all but one patient, who was followed up for only 3 months. The JOA scores Japanese Orthopaedic Association (JOA) Scores for low back pain of all patients significantly improved at the final follow-up. OLIF provides a safe and effective salvage strategy for patients with failed posterior intervertebral fusion surgery. Patients effectively recovered intervertebral and foraminal height with no additional posterior direct decompression.

Fixation-induced surgical segment’s high stiffness and the damage of posterior structures together trigger a higher risk of adjacent segment disease in patients with lumbar interbody fusion operations

BackgroundAdjacent segment disease (ASD) is a commonly reported complication after lumbar interbody fusion (LIF); changes in the mechanical environment play an essential role in the generation of ASD. Traditionally, fixation-induced high stiffness in the surgical segment was the main reason for ASD. However, with more attention paid to the biomechanical significance of posterior bony and soft structures, surgeons hypothesize that this factor may also play an important role in ASD.MethodsOblique and posterior LIF operations have been simulated in this study. The stand-alone OLIF and OLIF fixed by bilateral pedicle screw (BPS) system have been simulated. The spinal process (the attachment point of cranial ligamentum complex) was excised in the PLIF model; the BPS system has also been used in the PLIF model. Stress values related to ASD have been computed under physiological body positions, including flexion, extension, bending, and axial rotations.ResultsCompared to the stand-alone OLIF model, the OLIF model with BPS fixation suffers higher stress values under extension body position. However, there are no apparent differences under other loading conditions. Moreover, significant increases in stress values can be recorded in flexion and extension loading conditions in the PLIF model with posterior structures damage.ConclusionsFixation-induced surgical segment’s high stiffness and the damage of posterior soft tissues together trigger a higher risk of ASD in patients with LIF operations. Optimizing BPS fixation methods and pedicle screw designs and reducing the range of posterior structures excision may be an effective method to reduce the risk of ASD.

Outcomes of patients undergoing single-level arthroplasty versus anterior lumbar interbody fusion.

Compared to vertebral body fusion, artificial discs are thought to lessen the risks of adjacent segment disease and the need for additional surgery by maintaining spinal mobility as they mimic the intervertebral disc structure. No studies have compared the rates of postoperative complications and the requirement for secondary surgery at adjacent segments among patients who have undergone anterior lumbar interbody fusions (ALIF) versus those undergoing lumbar arthroplasty. An all-payer claims database identified 11,367 individuals who underwent single-level ALIF and lumbar arthroplasty for degenerative disc disease (DDD) between January 2010 and October 2020. Rates of complications following surgery, the need for additional lumbar surgeries, length of stay (LOS), and postoperative opioid utilization were assessed in matched cohorts based on logistic regression models. Kaplan-Meyer plots were created to model the probability of additional surgery. Following 1:1 exact matching, 846 records of patients who had undergone ALIF or lumbar arthroplasty were analyzed. All-cause readmission within 30-30days following surgery was significantly higher in patients undergoing ALIF versus arthroplasty (2.6% vs. 0.71%, p = 0.02). LOS was significantly lower among the patients who had undergone ALIF (1.043 ± 0.21 vs. 2.17 ± 1.7, p < .001). ALIF and lumbar arthroplasty procedures are equally safe and effective in treating DDD. Our findings do not support that single-level fusions may biomechanically necessitate revisional surgeries.

Risk Factors for Adjacent Segment Disease in Short Segment Lumbar Interbody Fusion-A Case Series.

Adjacent segment disease (ASD) is a common problem after lumbar spinal fusions. Ways to reduce the rates of ASD are highly sought after to reduce the need for reoperation. To find predisposing factors of ASD after lumbar interbody fusions, especially in mismatch of pelvic incidence and lumbar lordosis (PI-LL). We conducted a retrospective cohort study of all patients undergoing lumbar interbody fusions of less than 4 levels from June 2015 to July 2020 with at least 1 year of follow-up and in those who had obtained postoperative standing X-rays. We found 243 patients who fit inclusion and exclusion criteria. Fourteen patients (5.8%) developed ASD, at a median of 24 months. Postoperative lumbar lordosis was significantly higher in the non-ASD cohort (median 46.4° ± 1.4° vs 36.9° ± 3.6°, P < .001), pelvic tilt was significantly lower in the non-ASD cohort (16.0° ± 0.66° vs 20.3° ± 2.4°, P = .002), PI-LL mismatch was significantly lower in the non-ASD cohort (5.28° ± 1.0° vs 17.1° ± 2.0°, P < .001), and age-appropriate PI-LL mismatch was less common in the non-ASD cohort (34 patients [14.8%] vs 13 [92.9%] of patients with high mismatch, P < .001). Using multivariate analysis, greater PI-LL mismatch was predictive of ASD (95% odds ratio CI = 1.393-2.458, P < .001) and age-appropriate PI-LL mismatch was predictive of ASD (95% odds ratio CI = 10.8-970.4, P < .001). Higher PI-LL mismatch, both age-independent and when adjusted for age, after lumbar interbody fusion was predictive for developing ASD. In lumbar degenerative disease, correction of spinopelvic parameters should be a main goal of surgical correction.

TLIF is Associated with Lower Rates of Adjacent Segment Disease and Complications Compared to ALIF: A Matched-Cohort Analysis.

Retrospective cohort. To compare the rate of adjacent segment disease (ASD) in patients undergoing anterior lumbar interbody fusion (ALIF) versus transforaminal lumbar interbody fusion (TLIF) for treatment of degenerative stenosis and spondylolisthesis. ALIF and TLIF are frequently used to treat Lumbar stenosis and spondylolisthesis. While both approaches have distinct advantages, it is unclear whether there are any differences in rates of ASD and postoperative complications. A retrospective cohort study of patients who underwent index 1-3 levels ALIF or TLIF between 2010-2022, using the PearlDiver Mariner Database, an all-claims insurance database (120 million patients). Patients with a history of prior lumbar surgery and those undergoing surgery for cancer, trauma, or infection were excluded. Exact 1:1 matching was performed using demographic factors, medical comorbidities, and surgical factors found to be significantly associated with ASD in a linear regression model. The primary outcome was a new diagnosis of ASD within 36 months of index surgery and secondary outcomes were all-cause medical and surgical complications. Exact 1:1 matching resulted in two equal groups of 106,451 patients undergoing TLIF and ALIF. The TLIF approach was associated with a lower risk of ASD (RR 0.58, 95% CI 0.56-0.59, P < 0.001), and all-cause medical complications (RR 0.94, 95% CI 0.91-0.98, P=0.002). All-cause surgical complications were not significantly different between both groups. After 1:1 exact matching to control for confounding variables, this study suggests that for patients with symptomatic degenerative stenosis and spondylolisthesis, a TLIF procedure (compared to ALIF) is associated with a decreased risk of developing ASD within 36 months of index surgery. Future prospective studies are needed to corroborate these findings. III.

Novel Applications of Robot-Assisted Navigation in the Treatment of Lumbar Adjacent Segment Disease: A Case Series

Novel Applications of Robot-Assisted Navigation in the Treatment of Lumbar Adjacent Segment Disease: A Case Series

Comparison of revision surgery for pseudarthrosis with or without adjacent segment disease after anterior cervical discectomy and fusion

BackgroundPatients with a pseudarthrosis after anterior cervical discectomy and fusion (ACDF) may have concurrent adjacent segment disease (ASD). Although prior studies have shown posterior cervical decompression and fusion (PCDF) is effective in repairing pseudarthrosis, improvement in patient reported outcomes (PROs) has been marginal. The aim of this study is to evaluate the effectiveness of PCDF in achieving symptom relief in patients with pseudarthrosis after ACDF and whether that is altered by the additional treatment of ASD. MethodsThirty-two patients with pseudarthrosis were compared with 31 patients with pseudarthrosis and concurrent ASD after ACDF who underwent revision PCDF with a minimum 1-year follow-up. Primary outcomes measures included the neck disability index (NDI), and numerical rating scale (NRS) scores for neck and arm pain. Secondary measures included estimated blood loss (EBL), operating room (OR) time, and length of stay. ResultsDemographics between cohorts were similar, however there was a significantly higher mean body mass index (BMI) in the group with concurrent ASD (32.23 vs. 27.76, p=.007). Patients with concurrent ASD had more levels fused during PCDF (3.7 vs. 1.9, p<.001), greater EBL (165 cc vs. 106 cc, p=.054), and longer OR time (256 minutes vs. 202 minutes, p<.000). Preoperative PROs for NDI (56.7 vs. 56.5, p=.954), NRS arm pain (5.9 vs. 5.7, p=.758), and NRS neck pain (6.6 vs. 6.8, p=.726) were similar in both cohorts. At 12 months patients with concurrent ASD experienced a slightly greater, but not statistically significant, improvement in PROs (Δ NDI 4.40 vs. -1.44, Δ NRS neck pain 1.17 vs. 0.42, Δ NRS arm pain 1.28 vs. 0.10, p=.107). ConclusionsPCDF is a standard procedure for treatment of pseudarthrosis following ACDF, however improvements in PROs are marginal. Slightly greater improvements were seen in patients whose indication for surgery also included concurrent ASD, rather than a diagnosis of pseudarthrosis alone.

Does decompression adjacent to arthrodesis in the lumbar spine predispose patients to adjacent segment degeneration and disease: A retrospective analysis

BackgroundThe treatment for multi-level spinal stenosis in the setting of single-level instability is a common operative scenario for surgeons who treat degenerative lumbar spine pathology. However, there is conflicting evidence regarding the inclusion of adjacent “stable” levels in the arthrodesis construct because of the potential for iatrogenic instability placed on those segments with decompressive laminectomy alone. This study aims to determine whether decompression adjacent to arthrodesis in the lumbar spine is a risk factor for adjacent segment disease (AS Disease). MethodsA retrospective analysis identified consecutive patients over a three-year period who underwent single-level posterolateral lumbar fusion (PLF) in the setting of single or multi-level spinal stenosis. Patients were required to have a minimum of two-year follow-up. AS Disease was defined as the development of new radicular symptoms referable to a motion segment adjacent to the lumbar arthrodesis construct. The incidence of AS Disease and reoperation rates were compared between cohorts. Results133 patients met the inclusion criteria with an average follow-up of 54 months. Fifty-four patients had a PLF with adjacent segment decompression, and 79 underwent a single-segment decompression and PLF. 24.1% (13/54) of patients who had a PLF with adjacent level decompression developed AS Disease resulting in a 5.5% (3/54) reoperation rate. 15.2% (12/79) of patients who did not receive an adjacent level decompression developed AS Disease resulting in a reoperation rate of 7.5% (6/79). There was neither a significantly higher rate of AS Disease (p = 0.26) nor reoperation (p = 0.74) between the cohorts. ConclusionsDecompression adjacent to single-level PLF was not associated with an increased rate of AS Disease relative to single-level decompression and PLF.

Stand-Alone Oblique Lumbar Interbody Fusion (OLIF) for the Treatment of Adjacent Segment Disease (ASD) after Previous Posterior Lumbar Fusion: Clinical and Radiological Outcomes and Comparison with Posterior Revision Surgery.

Background: Radiological evidence of adjacent segment disease (ASD) has been reported to have a prevalence of more than 30% and several risk factors have been reported. The aim of this study is to evaluate the clinical and radiological outcomes of patients with symptomatic ASD treated with stand-alone OLIF and compare results with a posterior revision surgery cohort. Methods: This is a retrospective case-control study. Clinical-patient-reported outcomes were obtained at preoperative, postoperative and final follow-up visits using the Short Form (SF-36) scale, the Oswestry Disability Index (ODI) and the visual analog scale (VAS). Radiological measures include lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence-lumbar lordosis (PI-LL) mismatch, segmental coronal Cobb angle and intervertebral disc height (DH). The data are compared with a retrospective series of patients that underwent a posterior revision surgery for ASD. Results: Twenty-eight patients in the OLIF group and 25 patients in the posterior group meet inclusion criteria. The mean ages at the time of the surgery are 65.1 years and 67.5, respectively. The mean follow-up time is 36.1 months (range of 14-56). The clinical outcomes significantly improve from preoperative values from the surgery in both groups. The radiological parameters are significantly improved postoperatively and were maintained at the last follow-up in both groups. A statistically significant difference is observed between the two groups for minor complication rate, length of surgery, blood loss and DH restoration. Conclusions: Stand-alone OLIF is an effective and safe technique with low morbidity and complication rates for the treatment of selected patients with symptomatic ASD following a previous lumbar fusion.

Letter to the Editor: Postoperative Sagittal Balance Has Only a Limited Role in the Development of Adjacent Segment Disease After Lumbar Spine Fusion for Degenerative Lumbar Spine Disorders A Subanalysis of the 10-Year Follow-up Study.

Sethy, Siddharth S. MBBS, MS (Orthopaedics); Goyal, Nikhil MBBS, MS (Orthopaedics); Kandwal, Pankaj MBBS, MS (Orthopaedics) Author Information

Reply to Letter to the Editor Regarding the Article "Postoperative Sagittal Balance has Only a Limited Role in the Development of Adjacent Segment Disease after Lumbar Spine Fusion for Degenerative Lumbar Spine Disorders: A Subanalysis of the 10-year Follow-up Study".

Toivonen, Leevi A. MD, PhDa; Mäntymäki, Heikki MD, PhDa; Häkkinen, Arja PhDb; Kautiainen, Hannu PhDc; Neva, Marko H. MD, PhDa Author Information

Lumbar Arthroplasty is Associated with a Lower Incidence of Adjacent Segment Disease Compared to ALIF: A Propensity Matched Analysis.

Retrospective Cohort Study. To compare the rate of ASD between lumbar disc arthroplasty (LDA) and anterior lumbar interbody fusion (ALIF). Lumbar disc arthroplasty (LDA) and anterior lumbar interbody fusion (ALIF) are alternative surgical approaches used to treat lumbar degenerative disc disease. However, there is a paucity of studies comparing the risk of adjacent segment disease (ASD) following these procedures. Patients who underwent 1-2 level LDA or ALIF between 2010 and 2022 were identified in the PearlDiver Mariner insurance all-claims database. Exclusion criteria included history of prior lumbar spine surgery, or surgery for tumors, trauma, or infection. 1:1 propensity matching was performed using demographic factors, medical comorbidities, and surgical factors which were significantly associated with ASD. 1:1 Propensity matching created two equal groups of 1,625 patients without baseline differences who underwent LDA or ALIF. LDA was significantly associated with a lower risk of ASD (RR 0.932, 95% CI 0.899-0.967, P<0.001), and need for revision within 30 days (RR 0.235, 95% CI 0.079-0.698, P=0.007). There were no differences in all-cause surgical and medical complications between both groups. After risk adjustment for demographic and clinical characteristics, the results suggest that LDA is associated with a lower risk of adjacent segment disease compared to ALIF. LDA was also associated with lower hospital cost and shorter length of stay.

The anatomic study and surgical technique for canal decompression with “pedicle-plasty” strategy in lumbar burst fractures with pedicle rupture

ABSTRACT In the treatment of lumbar burst fractures with nerve injury, fusion is often required to rebuild spinal stability, but it can lead to the loss of motor units and increase the occurrence of adjacent segment diseases. Thus, a novel approach of lumbar canal decompression with “pedicle-plasty” strategy (DDP) was needed in clincal treatment. Firstly, image measurement analysis, the images of 60 patients with lumbar spine CT examinations were selected to measure osteotomy angle (OA), distance from the intersection of osteotomy plane and skin to the posterior midline (DM),transverse length of the osteotomy plane (TLOP), and sagittal diameter of the outer edge of superior articular process (SD). Secondary, cadaver study, distance between the intermuscular space and midline (DMSM), anterior and posterior diameters of the decompression (APDD), and lateral traction distance of the lumbosacral plexus (TDLP) were measured on 10 cadaveric specimens. Finally, procedure of DDP was demonstrated on cadaver specimens. OA ranged from 27.68°+4.59° to 38.34°+5.97°, DM ranged from 43.44+6.29 to 68.33+12.06 mm, TLOP ranged from 16.84+2.19 to 19.64+2.36 mm, and SD ranged from 22.49+1.74 to 25.53+2.21 mm. DMSM ranged from 45.53+5.73 to 65.46+6.43 mm. APDD were between 10.51+3.59 and 12.12+4.54 mm, and TDLP were between 3.28+0.81 and 6.27+0.62 mm.DDP was successfully performed on cadaveric specimens. DDP, as a novel approach of decompression of burst fractures with pedicle rupture, can fully relieve the occupation and at the same time preserve the spinal motor unit because of no resection of intervertebral discs and no destruction of facet joints,and has certain developmental significance.

Spine

The April 2023 Spine Roundup360 looks at: Percutaneous transforaminal endoscopic discectomy versus microendoscopic discectomy; Spine surgical site infections: a single debridement is not enough; Lenke type 5, anterior, or posterior: systematic review and meta-analysis; Epidural steroid injections and postoperative infection in lumbar decompression or fusion; Noninferiority of posterior cervical foraminotomy versus anterior cervical discectomy; Identifying delays to surgical treatment for metastatic disease; Cervical disc replacement and adjacent segment disease: the NECK trial; Predicting complication in adult spine deformity surgery.

356 Intraoperative Robotic Planning Software is Accurate at Predicting Postoperative Lumbar Lordosis After Anterior Column Reconstruction

INTRODUCTION: Re-establishment of lumbar lordosis with spine deformity surgery is considered a pre-requisite for long term positive results with less biomechanical loading on the adjacent segments, reducing the likelihood of developing adjacent segment disease. The pre-operative planning softwares of robotic systems now allow the surgeon to plan a patient-specific surgical plan and are also able to predict the degree of lumbar lordosis following the instrumentation surgery based on pre-operative imaging by using vertebral segmentation. METHODS: We conducted a retrospective review of patients aged 18 or older who underwent pedicle screw spinal instrumentation using the Mazor X Robot (Medtronic Inc., Minneapolis, MN, USA), performed by one surgeon over a five-year period. The robotic guidance software (Mazor X-Align, Medtronic Inc., Minneapolis, MN, USA) was used to calculate the predicted lumbar lordosis based on pre-operative imaging. Wilcoxon Rank test was used to compare the predicted angles to the observed lumbar lordosis on post-operative radiographs. RESULTS: A total of 15 patients (46.6% female) with a mean age of 61.5 ± 10.9 years were identified, who underwent posterior lumbo-sacral spinal fusion with the robotic system using both percutaneous and open approach. Instrumentation was done across a mean of 3.27 levels per case and 11 patients (73.3%) underwent anterior column reconstruction prior to posterior fixation without the need for an intra-operative CT spin. There was no statistical difference between the predicted and the actual post-operative lumbar lordosis (p-value: 0.334) while there was a significant statistical difference between the pre-operative and post-operative angles (p-value: 0.02). CONCLUSIONS: Our study suggests that the intraoperative robotic planning software of the Mazor X system is accurate at predicting postoperative lumbar lordosis which can be useful and help guide surgical decision making and planning.

Up to 10-year surveillance comparison of survivability in single-level cervical disc replacement versus anterior cervical discectomy and fusion in New York.

Cervical disc replacement (CDR) is an alternative treatment to anterior cervical discectomy and fusion (ACDF), which is the current gold standard, for degenerative cervical diseases such as cervical spondylotic myelopathy and cervical radiculopathy. CDR has several theoretical benefits over ACDF, including preservation of motion, earlier return to unrestricted activity, and potentially a lower risk of adjacent-segment disease. Recent literature has reported positive clinical results for CDR, but few studies have investigated the long-term risk of revision surgery of CDR versus ACDF. The purpose of this study was to identify and analyze the epidemiological, clinical, and operative risk factors that affect revision rates following single-level CDR and ACDF procedures. A retrospective cohort was extracted from the Statewide Planning and Research Cooperative System using ICD-9 and CPT codes. Inclusion criteria were adult patients undergoing primary, subaxial (C3-7), single-level ACDF or CDR for cervical radiculopathy and/or cervical spondylotic myelopathy between 2005 and 2013. Survivability was defined as the time between the index procedure and the presence of a subsequent discharge record for cervical spinal fusion or disc replacement. Statistical analyses were performed using chi-square tests, t-tests, Cox proportional hazards models, and a Kaplan-Meier plot. A total of 7450 patients were included in this study (6615 ACDF and 835 CDR). When adjusted for patient demographics, the hazard ratios showed no significant differences in the incidence of revision risk between the two cohorts. The CDR cohort had a higher incidence of postoperative dysphagia (p < 0.05). Patients undergoing ACDF had a longer average hospital stay (2.8 vs 1.9 days, p < 0.001). There was no significant difference in time to revision surgery (p = 0.486). CDR and ACDF have both been shown to be effective treatments for cervical spine disease. CDR patients had a shorter average inpatient hospital stay compared with ACDF patients but tended to experience dysphagia more frequently. There was a tendency toward increased survivability of CDR; however, this was not found to be statistically significant at any time point. The large size and heterogeneity of each cohort and the availability of > 10 years of surveillance data differentiate this study from other published literature. This investigation has limitations inherent to large data analysis studies, including the implementation and inaccuracy of diagnosis and procedural coding; however, this reflects real-world use of coding by practitioners.