Non-fusion Group Research Articles

Spontaneous Lumbar Interbody Fusion Following Posterolateral Fusion Surgery: A Retrospective Analysis of 5-Year Data.

Posterolateral fusion (PLF) surgery is frequently performed for a range of spinal disorders. However, spontaneous lumbar interbody fusion (SLIF) following PLF surgery is yet to be reported. Thus, we evaluated the incidence and characteristics of SLIF among patients that underwent PLF surgery. This retrospective study involved review of electronic medical records of 121 adult patients who underwent primary lumbar decompression with instrumented PLF between 2006 and 2011. The available radiographs of L2-S1 region were assessed for SLIF and PLF. At 1year, modified Lee's and Lenke's criteria were used to assess SLIF and PLF, respectively. Differences between the patients in the fusion and non-fusion groups were evaluated. At 1-year follow-up, 28.93 and 87.61% patients had SLIF and PLF, respectively. Moreover, 27.27% patients had both SLIF and PLF. L4-L5 (n = 13) was the most common segment involved in SLIF. SLIF rate was significantly greater among young adults (p value = 0.001), and those with no pre-operative instability (p value = 0.003) as well as who underwent pedicular fixation instrumented PLF surgery (p value < 0.0001). While, PLF was significantly greater in patients who did not undergo discectomy (p value = 0.049). SLIF was not significantly associated with sex, age groups, discectomy status, and level of PLF surgery (all p values > 0.05). PLF was not significantly associated with sex, age groups, pre-operative instability, type of instrumentation, and level of PLF surgery (all p values > 0.05). There was no significant association between patients with SLIF and PLF (p value = 0.155). More than a quarter of patients developed SLIF and majority of them had PLF. SLIF was significantly associated with younger age at surgery and use of pedicular fixation instruments.Level of Evidence III; retrospective cohort study.

Pack Years of Tobacco Cigarette Smoking as a Predictor of Bony Fusion after Anterior Cervical Discectomy and Fusion

Smoking tobacco cigarettes negatively impacts bone healing after spinal fusion. Smoking history is often assessed based on current smoker and nonsmoker status. However, in current research, smoking history has not been quantified in terms of pack years to estimate lifetime exposure and assess its effects. Our goal was to investigate the influence of smoking history, quantified in pack years, on bony fusion after anterior cervical discectomy and fusion (ACDF). A retrospective chart review of consecutive patients who underwent ACDF for cervical disc degeneration between September 21, 2017 and October 17, 2018 was conducted. Patient demographics, procedural variables, and postoperative outcomes were analyzed. Multivariate logistic regression analysis was performed to identify predictive factors for bony fusion following ACDF. Receiver operating characteristic curve analysis was used to determine the optimal discrimination threshold for smoking history pack years in association with nonfusion. Among 97 patients identified, 90 (93%) demonstrated bony fusion on postoperative imaging. Mean number of smoking history pack years was 6.1±13 for the fusion group and 16±21 for the nonfusion group. Multivariate logistic regression analysis suggested that increased pack years of tobacco cigarette smoking was a significant predictor of nonfusion (95% confidence interval, [1.0,1.1], P= 0.045). The receiver operating characteristic curve analysis revealed that 6.1 pack years best stratified the risk for nonfusion (area under the curve, 0.8). Patients with a history of tobacco cigarette smoking ≥6.1 pack years may have an increased risk of nonfusion after ACDF.

Development and in vivo biomechanics of goat mobile artificial lumbar spine complex

Mobile artificial lumbar complex (MALC) which suitable for reconstruction after subtotal lumbar resection in goats was developed,and to test stability of the complex and postoperative lumbar segmental motor function. Eighteen male boer goats aged from 1 to 2 years old (weighted from 35 to 45 kg) were selected and divided into control group,fusion group and non-fusion group,with 6 goats in each group. According to preoperative CT scans and MRI examinations of lumbar,the goat MALC was designed and performed by 3D printed for non-fusion group. Operation was performed on three groups respectively,and only vertebral body and disc were exposed in control group. In fusion group,L4 part of vertebral body and the upper and lower complete disc tissues were removed,and the lumbar spine bone plate fixation was performed with titanium mesh bone grafting. In non-fusion group,vertebral body and disc were removed in the same way,and MALC was implanted. AP and lateral X-rays of lumbar vertebrae in goat were taken at 6 months after surgery,in order to understand whether the plant was dislocated,displaced and fractured. Biomechanical tests were performed on the specimens by mechanical instrument to measure range of motion (ROM) of L2,3,L3,4,L4,5 intervertebral space and the overall ROM of L2-5 lumbar vertebrae. MALC of lumbar vertebra was designed by 3D printing,and its component artificial vertebrae and upper and lower artificial end plates were manufactured. The semi-spherical structure was fabricated by precision lathe using high-crosslinked polyethylene material,and the prosthesis was assembled. Postoperative AP and lateral X-rays of lumbar vertebra at 6 months showed the implant position of implant and MALC were good without displacement and dislocation. In vitro biomechanical test of lumbar vertebrae specimens:(1) There were no statistical significance in ROM of lumbar intervertebral space flexion and extension,lateral flexion and rotation on L3,4 and L4,5,between non-fusion group and control group (P>0.05),while ROM of fusion group was significantly reduced compared with the other two groups (P<0.05). There were no significant difference in ROM of L2,3 intervertebral flexion and extension,lateral flexion and rotation between non-fusion group and control group (P>0.05),while fusion group was significantly increased compared with the other two groups (P<0.001). (2) There was no significant difference in overall lumbar ROM of L2-5 (P> 0.05). The individual MALC could restore intervertebral height of lumbar vertebra while maintaining the stability of lumbar vertebra and re-establishing motor function of lumbar space.

Factors associated with non-fusion after direct pars repair of lumbar spondylolysis with pedicle screw and lamina hook: a clinical and CT-assessed study

BackgroundPedicle screw and lamina hook (PSLH) technique is an effective and popular method for direct pars repair of lumbar spondylolysis. There is a lack of studies to explore factors that may influence the healing of spondylolysis after direct pars repair surgery. The present study aimed to investigate the factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PSLH technique.MethodsA total of 55 subjects (average age 21.1 ± 6.3 years, a total of 120 pars defects) diagnosed with symptomatic spondylolysis and underwent pars repair surgery with PSLH were followed up and their clinical data were analyzed. Subjects were divided into a non-fusion group and fusion group according to whether the pars defect had bony fusion at last follow-up assessed by CT. Radiographic data, data related to spondylolysis and clinical outcomes were collected and compared between groups.ResultsThe mean follow-up time of the 55 patients was 24.8 ± 12.0 (12–64) months. Among the 120 pars defects, 101 defects were successfully fused and 19 were not fused according to CT. The fusion rate was 84.2%. Multivariable logistic regression analysis showed the factors correlated with non-fusion after pars repair surgery: whether the spondylolysis segment was associated with spina bifida occulta (SBO) (P = 0.001), stage of the defect (P = 0.047), width of the defect (P = 0.002), and disc degeneration (P = 0.014).ConclusionDirect pars repair by PSHL is a reliable treatment for lumbar spondylolysis with a fusion rate of 84.2%. Association with SBO of the spondylolysis segment, a terminal stage of the defect, a wider defect gap, and grade III disc degeneration may be factors associated with non-fusion after direct pars repair of lumbar spondylolysis with PLSH. Non-fusion patients after pars repair appear to have worse clinical results compared to fusion patients.

The Effect of Unintended Facet Arthrodesis on the Treatment Outcome of Dynamic Neutralization System for Lumbar Degenerative Diseases.

This study aimed to examine the influence of unintended facet arthrodesis on the therapeutic effectiveness of the dynamic neutralization system (Dynesys). This retrospective study enrolled consecutive patients who underwent posterior decompression and dynamic stabilization for lumbar spondylosis or spinal stenosis. Follow-up assessments included lumbar radiography, lumbar vertebral computerized tomography (CT), visual analog scale (VAS), and Oswestry disability index (ODI). Patients were classified into the facet fusion and non-fusion groups. The differences in the VAS scores for back pain and leg pain, ODI, intervertebral range of motion (ROM) at the surgical segments, and upper adjacent segments were assessed before and after treatment. A total of 49 patients (29 males and 20 females) aged 31-65years were enrolled and followed-up for over 40months. Among the patients, 16 (32.7%) experienced unintended facet arthrodesis and were assigned to the fusion group, whereas the remaining patients were assigned to the non-fusion group. There was a significant increase in the incidence of facet arthrodesis in the surgical segments over time post-surgery (χ2 = 6.2, p < 0.05). The ROM of the surgical and upper adjacent segments, VAS scores for back pain and leg pain, and ODI were all significantly different before and after the operation (p < 0.05), but not between the fusion and non-fusion groups (p > 0.05). Although unintended facet arthrodesis is common after Dynesys procedure, the presence of facet arthrodesis does not significantly affect the efficacy of Dynesys in treating lumbar degenerative diseases.

Serum antioxidant enzymes in spinal stenosis patients with lumbar disc herniation: correlation with degeneration severity and spinal fusion rate

ObjectiveTo determine whether superoxide dismutase (SOD) and glutathione reductase (GR) correlated with the intervertebral disc degeneration (IDD) severity and the postoperative spinal fusion rate in lumbar spinal stenosis patients accompanied with lumbar disc herniation.MethodsThis retrospective study investigated 310 cases of posterior lumbar decompression and fusion. The cumulative grade was calculated by adding the pfirrmann grades of all the lumbar discs. Subjects were grouped based on the median cumulative grade. Logistic regression was used to determine the associations among the demographical, clinical, and laboratory indexes and severe degeneration and fusion. The receiver operating characteristic (ROC) curve was performed to measure model discrimination, and Hosmer-Lemeshow (H-L) test was used to measure calibration.ResultsSOD and GR levels were significantly lower in the severe degeneration group (cumulative grade > 18) than in the mild to moderate degeneration group (cumulative grade ≤ 18). Furthermore, the SOD and GR concentrations of the fusion group were significantly higher than that of the non-fusion group (p < 0.001 and p = 0.006). The multivariate binary logistic models revealed that SOD and GR were independently influencing factors of the severe degeneration (OR: 0.966, 95%CI: 0.950–0.982, and OR: 0.946, 95%CI: 0.915–0.978, respectively) and non-fusion (OR: 0.962; 95% CI: 0.947–0.978; OR: 0.963; 95% CI: 0.933–0.994). The models showed excellent discrimination and calibration. Trend analysis indicated that the levels of SOD and GR tended to decrease with increasing severity (p for trend < 0.001 and 0.003). In addition, it also revealed that SOD provided protection from non-fusion in a concentration-dependent manner (p for trend < 0.001). However, GR concentration-dependent effects were not apparent (p for trend = 0.301).ConclusionHigh serum SOD and GR levels are associated with a better fusion prognosis and a relief in degeneration severity.

Risk Factors of Nonfusion after Anterior Cervical Decompression and Fusion in the Early Postoperative Period: A Retrospective Study.

Although high fusion rates have been reported for anterior cervical decompression and fusion (ACDF) in the medium and long term, the risk of nonfusion in the early period after ACDF remains substantial. This study investigates early risk factors for cage nonfusion in patients undergoing single- or multi-level ACDF. This was a retrospective study. From August 2020 to December 2021, 107 patients with ACDF, including 197 segments, were enrolled, with a follow-up of 3 months. Among the 197 segments, 155 were diagnosed with nonfusion (Nonfusion group), and 42 were diagnosed with fusion (Fusion group) in the early period after ACDF. We assessed the significance of the patient-specific factors, radiographic indicators, serum factors, and clinical outcomes. The Wilcoxon rank sum test, t-tests, analysis of variance, and stepwise multivariate logistic regression were used for statistical analysis. Univariate analysis showed that smoking, insufficient improvement in the C2-7 Cobb angle (p = 0.024) and the functional spinal unit Cobb angle (p = 0.022) between preoperative and postoperative stages and lower serum calcium (fusion: 2.34 ± 0.12 mmol/L; nonfusion: 2.28 ± 0.17 mmol/L, p = 0.003) β-carboxyterminal telopeptide end of type 1 collagen (β-CTX) (fusion: 0.51 [0.38, 0.71]; nonfusion: 0.43 [0.31, 0.57], p = 0.008), and N-terminal fragment of osteocalcin (N-MID-BGP) (fusion: 18.30 [12.15, 22.60]; nonfusion: 14.45 [11.65, 18.60], p = 0.023) are risk factors for nonfusion in the early period after ACDF. Stepwise logistic regression analysis revealed that poor C2-7 Cobb angle improvement (odds ratio [OR], 1.107 [1.019-1.204], p = 0.017) and lower serum calcium (OR, 3.700 [1.138-12.032], p = 0.030) are risk factors. Patients with successful fusion after ACDF had higher preoperative serum calcium and improved C2-7 Cobb angle than nonfusion patients at 3 months. These findings suggest that serum calcium could be used to identify patients at risk of nonfusion following ACDF and that correcting the C2-7 Cobb angle during surgery could potentially increase fusion in the early period after ACDF.

Radiological evaluation of atlantoaxial fusion using C2 translaminar screws and C2 pedicle screws: Does the screw halo sign imply fusion failure?

The purpose of this study was to identify the criteria for atlantoaxial (AA) fusion by comparing follow-up lateral radiographs and computed tomography (CT) images. We retrospectively analyzed data from 161 consecutive patients undergoing AA fusion. Patients with a minimum of 1 year of CT follow-up after AA fusion surgery using C2 pedicle screws or translaminar screws (C2TLS) were included. Patients were followed up radiographically at 3, 6, and 12 months after surgery, and dynamic lateral radiographs were also evaluated. A total of 49 patients were analyzed, with a mean CT image follow-up of 41.6 ± 37.6 months. Thirty eight patients had C2 pedicle screw placement, and 11 patients underwent planned C2TLS. AA fusion with bridging bone mass formation was achieved in 45/49 (91.8%) patients. Screw halos were observed in 14/49 (28.6%) patients. Among them, final fusion failure occurred in 2 (14.3%) patients. The last follow-up CT showed no difference in the fusion failure rate according to the presence or absence of a screw halo (no halo, 5.7%; halo, 14.3%; P = .33). The differences in C1-2 segmental angles (SA) in flexion-extension dynamic lateral radiographs were 1.99 ± 1.62° in the fusion group and 4.37 ± 2.13° in the non-fusion group (P = .01). The likelihood of fusion failure increased when the SA gap was greater than 2.62° (P = .05). C2TLS placement had a significantly higher incidence of screw halos. However, the halo sign was not significantly related to final bone fusion. Bone fusion could be predicted when the SA gap of C1-2 was less than 2.62° on the dynamic radiograph.

Preoperative Lymphocyte to Monocyte Ratio as a Predictive Biomarker for Disease Severity and Spinal Fusion Failure in Lumbar Degenerative Diseases Patients Undergoing Lumbar Fusion

ObjectiveThis study was designed to determine whether lymphocyte to monocyte ratio (LMR) correlated with the intervertebral disc degeneration (IDD) severity and the postoperative spinal fusion rate in patients with lumbar disc disease.Methods303 patients undergoing posterior lumbar decompression and fusion were retrospectively analyzed. An examination of the blood count was performed before surgery. The cumulative grade was calculated by summing the pfirrmann grades of all lumbar discs. Grouping was based on the 50th percentile of cumulative grade and spinal fusion. The relationship between LMR and IDD severity and spinal fusion was explored using correlation analyses and logistic regression models. The receiver operating characteristic (ROC) curve was performed to measure model discrimination, and Hosmer-Lemeshow (H-L) test was used to measure calibration. Meanwhile, the ROC curve evaluated the discrimination ability of LMR in predicting severe degeneration and fusion failure.ResultsLMR was significantly lower in the severe degeneration group (cumulative grade > 18) than in the mild to moderate degeneration group (cumulative grade ≤ 18). Furthermore, the LMR of the fusion group was significantly higher than that of the non-fusion group. The multivariate binary logistic models revealed that LMR was an independently influencing factor of the severe degeneration and fusion failure (OR: 0.793, 95% CI: 0.638–0.987, p = 0.038; OR: 0.371, 95% CI: 0.258–0.532, p < 0.001). The models showed excellent discrimination and calibration. The area under the curve (AUC) of severe degeneration and fusion failure identified by LMR were 0.635 and 0.643, respectively, and the corresponding cut-off values were 3.16 and 3.90.ConclusionLMR is significantly associated with the risk of severe disc degeneration and spinal fusion failure.

Risk Factors of Bone Nonfusion After Spinal Tuberculosis Debridement Bone Graft Fusion and Internal Fixation

ObjectiveTo retrospectively analyze bone graft nonfusion risk factors in spinal tuberculosis patients after lesion debridement, bone graft fusion and internal fixation.MethodsThe clinical data of 131 patients who underwent spinal tuberculosis debridement, bone graft fusion and internal fixation in our hospital from March 2015 to March 2018 were retrospectively analyzed. The patients were divided into two groups according to bone fusion after the operation; there were 37 patients in the nonfusion group and 94 in the fusion group. The basic information and follow-up data of the patients were collected to evaluate the risk factors for bone graft nonfusion 1 year after surgery.ResultsThe severity of osteoporosis in the nonfusion group was significantly greater than that in the fusion group (p < 0.05). There were statistically significant differences between the two groups in terms of continuous multisegment status, disease duration, intraoperative surgical methods and whether patients received standardized drug treatment for 12 months after surgery (p < 0.05). Multivariate logistic regression analysis showed that long disease duration, posterior approach, and degree of osteoporosis were risk factors for postoperative bone graft nonfusion (OR > 1, p < 0.05), while standard drug treatment for 1 year after surgery was a protective factor (OR < 1, p < 0.05).ConclusionSpinal tuberculosis patients who had a long disease course, who underwent simple posterior debridement, or who had severe osteoporosis had a higher risk of bone graft nonfusion after surgery. Tuberculosis treatment is beneficial for the osseous fusion of the postoperative bone graft area.

Clinical Results of Restoration of Pars Interarticularis Defect in Adults with Percutaneous Intralaminar Screw Fixation

This study aims to report the clinical outcomes associated with the percutaneous intralaminar screw repair performed for pars defects in adults. Adult patients who got their lumbar L5 spondylolysis repaired via modified Buck's procedure between 2017 and 2020 were retrospectively evaluated. The preoperative and postoperative clinical outcomes at 1, 3, 6, and 12months were evaluated for patients with and without fusion using the visual analog scale, Oswestry Disability Index, and the Short-Form Health Survey 36 (SF-36). At 12months, the fusion status of all the patients was assessed using bilateral direct X-rays. Thirty patients with spondylolysis were identified (11 men and 19 women). All patients had bilateral L5 pars defects, and at 12months, the fusion rate was 60% (18/30). There was no difference between the fusion and nonfusion groups in terms of their visual analog scale, Oswestry Disability Index, and SF-36 physical component summary and SF-36 mental component summary scores (P>0.05). Within-group comparisons of the 2 groups revealed significant changes at follow-up (P<0.05). Minimally invasive repair of lumbar spondylolysis with percutaneous intralaminar screw fixation restores the motion segment and can provide early resumption of physical activity with minimal muscle damage, smaller skin incision, and less soft tissue dissection.

Spinal anesthesia in contemporary and complex lumbar spine surgery: experience with 343 cases.

Spinal anesthesia (SA) is an alternative to general anesthesia (GA) for lumbar spine surgery, including complex instrumented fusion, although there are relatively few outcome data available. The authors discuss their experience using SA in a modern complex lumbar spine surgery practice to describe its utility and implementation. Data from patients receiving SA for lumbar spine surgery by one surgeon from March 2017 to December 2020 were collected via a retrospective chart review. Cases were divided into nonfusion and fusion procedure categories and analyzed for demographics and baseline medical status; pre-, intra-, and postoperative events; hospital course, including Acute Pain Service (APS) consults; and follow-up visit outcome data. A total of 345 consecutive lumbar spine procedures were found, with 343 records complete for analysis, including 181 fusion and 162 nonfusion procedures and spinal levels from T11 through S1. The fusion group was significantly older (mean age 65.9 ± 12.4 vs 59.5 ± 15.4 years, p < 0.001) and had a significantly higher proportion of patients with American Society of Anesthesiologists (ASA) Physical Status Classification class III (p = 0.009) than the nonfusion group. There were no intraoperative conversions to GA, with infrequent need for a second dose of SA preoperatively (2.9%, 10/343) and rare preoperative conversion to GA (0.6%, 2/343) across fusion and nonfusion groups. Rates of complications during hospitalization were comparable to those seen in the literature. The APS was consulted for 2.9% (10/343) of procedures. An algorithm for the integration of SA into a lumbar spine surgery practice, from surgical and anesthetic perspectives, is also offered. SA is a viable, safe, and effective option for lumbar spine surgery across a wide range of age and health statuses, particularly in older patients and those who want to avoid GA. The authors' protocol, based in part on the largest set of data currently available describing complex instrumented fusion surgeries of the lumbar spine completed under SA, presents guidance and best practices to integrate SA into contemporary lumbar spine practices.

Spontaneous Osseous Fusion after Remodeling Therapy for Chronic Atlantoaxial Rotatory Fixation and Recovery Mechanism of Rotatory Range of Motion of the Cervical Spine.

We aimed to investigate the risk factors of spontaneous osseous fusion (SOF) of the atlantoaxial joint after closed reduction under general anesthesia followed by halo fixation (remodeling therapy) for chronic atlantoaxial rotatory fixation, and to elucidate the recovery mechanism of the rotatory range of motion (ROM) after halo removal. Twelve patients who underwent remodeling therapy were retrospectively reviewed. Five patients with SOF were categorized as the fusion group and seven patients without SOF as the non-fusion group. Three dimensional CT was used to detect direct osseous contact (DOC) of facet joints before and during halo fixation, while dynamic CT at neutral and maximally rotated head positions was performed to measure rotatory ROM after halo removal. The duration from onset to initial visit was significantly longer (3.2 vs. 5.7 months, p = 0.04), incidence of DOC during halo fixation was higher (0/7 [0%] vs. 4/5 [80%], p = 0.004), and segmental rotatory ROM of Occiput/C1 (Oc/C1) at final follow-up was larger (9.8 vs. 20.1 degrees, p = 0.003) in the fusion group. Long duration from the onset to the initial visit might induce irreversible damage to the articular surface of the affected facet, which was confirmed as DOC during halo fixation and resulted in SOF. Long duration from the onset to the initial visit and DOC during halo fixation could be used to suggest the risk for SOF. Nonetheless, rotatory ROM of Oc/C1 increased to compensate for SOF.

Preclinical Evaluation of a Novel 3D-Printed Movable Lumbar Vertebral Complex for Replacement: In Vivo and Biomechanical Evaluation of Goat Model.

Purpose This was an in vivo study to develop a novel movable lumbar artificial vertebral complex (MLVC) in a goat model. The purpose of this study was to evaluate clinical and biomechanical characteristics of MLVC and to provide preclinical data for a clinical trial in the future. Methods According to the preoperative X-ray and CT scan data of the lumbar vertebrae, 3D printing of a MLVC was designed and implanted in goats. The animals were randomly divided into three groups: intact, fusion, and nonfusion. In the intact group, only the lumbar vertebrae and intervertebral discs were exposed during surgery. Both the fusion and nonfusion groups underwent resection of the lumbar vertebral body and the adjacent intervertebral disc. Titanium cages and lateral plates were implanted in the fusion group. MLVC was implanted in the nonfusion group. All groups were evaluated by CT scan and micro-CT to observe the spinal fusion and tested using the mechanical tester at 6 months after operation. Results The imaging results showed that with the centrum, the artificial endplates of the titanium cage and MLVC formed compact bone trabeculae. In the in vitro biomechanical test, the average ROM of L3-4 and L4-5 for the nonfusion group was found to be similar to that of the intact group and significantly higher in comparison to that of the fusion group (P < 0.05). The average ROM of flexion, extension, lateral bending, and rotation in the L2-3 intervertebral space significantly increased in the fusion group compared with the intact group and the nonfusion group (P < 0.001). There were no significant differences in flexion, extension, lateral bending, and rotation between the nonfusion and intact groups (P > 0.05). The average ROM of flexion, extension, lateral bending, and rotation in the L2-5 intervertebral space was not significantly different between the intact group, the fusion group, and the nonfusion group, and there was no statistical significance (P > 0.05). HE staining results did not find any metal and polyethylene debris caused by abrasion. Conclusion In vivo MLVC can not only reconstruct the height and stability of the centrum of the operative segment but also retain the movement of the corresponding segment.

Risk Factors for Spine Reoperation and Joint Replacement Surgeries after Short-Segment Lumbar Spinal Surgeries for Lumbar Degenerative Disc Disease: A Population-Based Cohort Study.

Background: Short-segment lumbar spinal surgery is the most performed procedure for treatment of degenerative disc disease. However, population-based data regarding reoperation and joint replacement surgeries after short-segment lumbar spinal surgery is limited. Methods: The study was a retrospective cohort design using the Taiwan National Health Insurance Research Database for data collection. Patients selected were diagnosed with lumbar degenerative disc disease and undergone lumbar discectomy surgery between 2002 and 2013. The Kaplan–Meier method was used to estimate the incidence of 1-year spine reoperation and joint replacement surgeries, and the Cox proportional hazard regression was used to examine risk factors associated with the outcomes of interest. Results: A total of 90,105 patients were included. Incidences of 1-year spine reoperation and joint replacement surgeries for the hip and knee were 0.27, 0.04, and 0.04 per 100 people/month. Compared to fusion with the fixation group, fusion without fixation and the non-fusion group had higher risks of spine reoperation. Risk factors associated with spine reoperation included fusion without fixation, non-fusion surgery, age ≥ 45 years old, male gender, diabetes, a Charlson Comorbidity Index = 0, lowest social economic status, and steroid use history. Spine surgeries were not risk factors for joint replacement surgeries. Conclusions: Non-fusion surgery and spinal fusion without fixation had higher risks for spine reoperation. Spine surgeries did not increase the risk for joint replacement surgeries.

Effect of micro-implant assisted rapid palatal expansion in patients with different radiographic stages of mid-palatal suture maturation

Objective: To evaluate the effect of micro-implant assisted rapid palatal expansion (MARPE) in patients with different radiographic stages of midpalatal suture maturation. Methods: Twenty-eight patients [7 males and 21 females; age (15.5±5.5) years] with maxillary transverse deficiency were selected in the Department of Orthodontics, Hospital of Stomatology, Jilin University from February 2017 to October 2019. According to the fusion of the midpalatal suture, the patients were divided into two groups: 10 patients [3 males and 7 females; age (19.9±6.9) years] were in fusion group and 18 patients [4 males and 14 females; age (13.0±2.4) years] were in non-fusion group. Each patient had cone-beam CT (CBCT) images taken immediately after the placement of micro-implants (T1) and the completion of maxillary expansion (T2). The CBCT images were analyzed using the Dolphin Imaging software to evaluate the amount of midpalatal expansion and the percentages of bony expansion, etc. Statistical analysis was carried out to compare the two groups. Results: After MARPE treatment, the amount of sutural expansion in fusion group was (3.23±1.45) mm while that in non-fusion group was (4.97±1.47) mm (P<0.05). There was a statistically significant difference in the percentages of bony expansion efficiency between the non-fusion group (71±20)% and the fusion group (46±18)% (P<0.05). Conclusions: Bony expansion efficiency was affacted by the radiographic stages of midpalatal suture maturation.

Complex Chiari Malformation: Proposal of a New Set of Diagnostic Criteria and Outcomes After fusion Surgery

The proposal of C1-C2 fusion as a better treatment option compared with foramen magnum decompression (FMD) for the treatment of Chiari 1 malformations has led to controversy. Although FMD is a time-tested treatment option, a group of patients exists who will benefit from C1-C2 fusion. We have proposed an objective system for defining complex Chiari malformations and studied the outcomes of fusion with decompression versus decompression alone for these patients. A total of 26 patients with complex Chiari malformations were identified using our criteria (any 4 of 7 clinicoradiological parameters). Of the 26 patients, 13 had undergone C1-C2 fusion with FMD and 13 had undergone FMD alone. They had also undergone pre- and postoperative clinicoradiological evaluations, and the outcomes were assessed using the Chicago Chiari outcome score. Of the 13 patients in the fusion group, 12 (92.3%) showed improvement compared with only 6 of 13 patients (46.2%) in the nonfusion group using the Chicago Chiari outcome score, a statistically significant difference (P= 0.036, χ2 test). The mean hospital length of stay was longer for the fusion group (6.15 ± 1.46 days) than for the nonfusion group (4.38 ± 2.22 days; P= 0.02). We have proposed a novel set of criteria for defining complex Chiari malformations. Fusion with decompression provided better outcomes than decompression alone.

Effects of vertebral fusion on levels of pro-inflammatory and catabolic mediators in a rabbit model of intervertebral disc degeneration.

The aim of this study was to explore the alterations in levels of pro-inflammatory and catabolic mediators following vertebral fusion in a rabbit model of intervertebral disc degeneration. In this study, 24 female New Zealand albino rabbits (aged 4 to 5 months and weighing 3 to 3.5 kg) were used. All the animals were randomly categorized into four groups, and dorsal spinal exposure of all lumbar vertebrae was routinely performed in each group. While disc degeneration was created in groups B, C, and D, spinal fusion was added to disc degeneration in groups C and D. Disc degeneration was typically created by puncturing the discs with an 18-gauge needle under the guidance of C-arm imaging. Fusion was achieved with posterior/posterolateral decortication and iliac bone grafts. The rabbits in groups A, B, and C were euthanized, and the discs were removed in the first week after the surgery. The rabbits in Group D were sacrificed, and the discs were harvested at 5 weeks after the surgery. The levels of Interleukin (IL)-1β, IL-6, Nitric Oxide (NO), Matrix Metalloproteinase (MMP)-3, MMP-13, and Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) in the discs were analyzed using enzyme-linked immunosorbent assay kits. Significant increase was observed in the protein levels of both pro-inflammatory and catabolic mediators in disc degeneration groups (Group B, C, and D) compared to Group A. In the fusion groups (Group C and D), these increased mediators decreased, compared to non-fusion group (Group B), (IL1-β P = 0.017, TIMP-1 P = 0.03, NO P = 0.03). However, there was no statistically significant difference in mediator levels between the short- and long-term fusion (Group C versus D). The results of this study have shown that a significant decrease in pro-inflammatory and catabolic mediators may be expected after vertebral fusion whereas there may be no significant difference between the first and fourth week of fusion surgery. These findings may contribute to clarifying the mechanism of action of vertebral fusion in the treatment of low back pain.

Analysis of Fracture Patterns and Characteristics in Sacral Insufficiency Fracture: Do Sacral Fractures Occur in Patients Who Had Previous Lumbosacral Fusion Insufficiency Fractures or Stress Fractures?

Study DesignThis study is a retrospective analysis of a case.PurposeThe purpose of this study is to investigate the fracture patterns and risk factors of sacral insufficiency fractures (SIFs) to improve their diagnosis in clinical practice.Overview of LiteratureSIFs occur when normal stresses are applied to a bone with decreased density, most often due to osteoporosis. Individuals who receive lumbosacral fusion procedures may also suffer from increased incidents of SIFs because of decreased bone density related to aging.MethodsIn total, 55 patients with SIFs were retrospectively investigated in this study. The study population was divided into lumbosacral fusion (n=20) and non-fusion (n=35) groups. Subsequently, the patients’ demographic characteristics, comorbidities, medication history, results of diagnostic imaging studies, and bone mineral density were assessed. The fracture patterns were classified either according to the five typical types (H-pattern bilateral vertical plus horizontal component, unilateral vertical only, bilateral vertical only, unilateral vertical plus horizontal component, and horizontal only fracture) or atypical types.ResultsIn total, 44 of 55 patients (80%) suffered from more than one senile disease and received corresponding medications that caused secondary osteoporosis. A total of 12 patients had S1 lumbosacral fixation. Moreover, three of these 12 patients who developed a SIF immediately after a lumbosacral fracture had an unstable sacral U fracture. The remaining nine patients showed fracture patterns similar to the non-fusion patients. Single-photon emission computed tomography (SPECT)/computed tomography (CT) can identify fracture recurrence in previously healed fractures. In total, 24 patients (43.6%) had fractures of the pelvis, femur, and thoracolumbar spine.ConclusionsSIF develops in elderly patients with multiple adult diseases that can induce secondary osteoporosis. Such fractures may occur in the patients with instrumented lumbosacral fusion. Importantly, some patients showed stress fractures after multilevel instrumented lumbosacral fusion, whereas others showed insufficiency fractures. The different fracture patterns correspond to different grades of SIF, and SPECT/CT can easily identify the fracture status.

Comparison of fusion versus non-fusion surgery for retro-odontoid pseudotumor with atlanto-axial subluxation

BackgroundDue to the limited number of reports comparing posterior fusion with posterior decompression alone for retro-odontoid pseudotumor, there remains no consensus on treatment preference, especially in older patients. This study compared posterior fusion (with or without additional decompression) with posterior decompression alone for treating spinal cord pressure from non-inflammatory retro-odontoid pseudotumor with atlanto-axial subluxation (AAS). MethodsForty-one patients (27 male and 14 female; mean age, 73.0 ± 11.4 years) who underwent either posterior cervical fusion or decompression alone for the treatment of non-inflammatory retro-odontoid pseudotumor with AAS and were observed for more than 1 year between September 2009 and July 2019 were enrolled. Thirty-two patients (23 male and 9 female; mean age: 71.8 ± 10.9 years) received posterior fusion surgery (fusion group) and 9 patients (4 male and 5 female; mean age: 77.2 ± 12.5 years) underwent decompression alone (non-fusion group). We compared pre- and postoperative Japanese Orthopaedic Association (JOA) scores and preoperative cervical alignment parameters between the groups. ResultsIn the fusion group, the mean preoperative JOA score was significantly improved from 9.0 ± 3.2 points to 11.7 ± 3.2 points at the final follow-up (p = 0.0002). Similarly in the non-fusion group, the mean preoperative and final follow-up JOA scores were 8.2 ± 3.5 points and 11.7 ± 3.8 points, respectively (p = 0.003). The recovery rate at the final follow-up was 22.6% in the fusion group and 43.4% in the non-fusion group, which were statistically comparable (p = 0.23). We observed no remarkable correlations between cervical sagittal spinal alignment parameters and JOA score recovery rate in the cohort, nor was any significant subluxation progression seen. ConclusionCompared with fusion surgery, surgical decompression alone may be a suitable and less invasive option for the treatment of non-inflammatory retro-odontoid pseudotumor with AAS, especially in elderly patients.