Lumbar Discectomy Using Tubular Retractor and Microendoscopy

BackgroundThe progression of disc degeneration is generally believed to be associated with low back pain and/or degenerative lumbar diseases, especially in the elderly. The purpose of this study was to quantitatively evaluate changes in lumbar disc height using radiographic measurements and to investigate risk factors for development of disc height narrowing of the elderly.MethodsFrom 1997 to 2007, 197 village inhabitants at least 65 years-old who participated in baseline examinations and more than four follow-up examinations conducted every second year were chosen as subjects for this study. Using lateral lumbar spine radiographs of each subject, L1-L2 to L5-S1 disc heights were measured. The subjects were divided into two groups according to the rate of change in disc height: mildly decreased (≤20 % decrease) and severely decreased (>20 % decrease). A stepwise multiple logistic regression analysis was used to select those factors significantly associated with disc height narrowing.ResultsDisc height at each intervertebral disc (IVD) level decreased gradually over ten years (p < 0.01, an average 5.8 % decrease of all disc levels). There was no significant difference in the rate of change in disc height among the IVD levels. Female gender, radiographic knee osteoarthritis and low back pain at baseline were associated with increased risk for disc height narrowing.ConclusionsWe conducted the first population-based cohort study of the elderly that quantitatively evaluated lumbar disc height using radiographic measurements. The risk factors identified in this study would contribute to a further understanding the pathology of disc degeneration.

Study Design : A retrospective study. Objective : To evaluate the usefulness of MRI grading of disc degeneration in determining whether L5-S1 fusion is necessary in degenerative lumbar spinal disorders. Summary of Literature Review : Changes in adjacent segments are not well understood, after floating fusion has been performed. Materials and Methods : We reviewed 16 surgical cases of degenerative lumbar spinal disorders from July 1996 to February 2000 with an average follow-up of 41 months. Fusion was done in patients without instability, pathology and narrowing of L5-S1. We measured the disc degeneration of adjacent segments in preoperative MRIs using the Modified Pearce classification. In spine AP, lateral and flexion-extension radiographs, we measured disc height, angular motion and instability changes and correlated these with disc degeneration. Results : Disc height changes decreased in the upper and lower adjacent segments and preoperative disc degeneration above grade IV, decreased more in lower adjacent segment. A statistical correlation was found between disc degeneration and disc height changes in the lower segment (P=0.046), but not in the upper segment (P=0.649). The angular-motion was unchanged in the upper and lower adjacent segments, and no statistical correlation was found between disc degeneration and angular-motion changes (P=0.819, 0.208). Postoperative instability was found in the upper adjacent segment in 2 patients, but no statistical correlation was found between disc degeneration and instability (P=0.083, P=1.000). Conclusion : L5-S1 might be saved when free of pathology, and when disc degeneration is below grade III and balanced sagittally. However, further study is needed because of the short-term follow up and low number of cases in this study.

145. Disc height assessment: interobserver variability and auto segmentation technology

To develop a decision-making pathway for primary SA-LLIF. Furthermore, we analyzed the agreement of this pathway and compared outcomes of patients undergoing either SA-LLIF or 360-LLIF. A decision-making pathway for SA-LLIF was created based on the results of interviews/surveys of senior spine surgeons with over 10years of experience. Internal validity was retrospectively evaluated using consecutive patients undergoing either SA-LLIF or 360-LLIF between 01/2018 and 07/2020 with 3D-printed Titanium cages. An outcome assessment looking primarily at revision surgery and secondary at cage subsidence, changes in disk and foraminal height, global and segmental lumbar lordosis, duration of surgery, estimated blood loss, and length of stay was carried out. 78 patients with 124 treated levels (37 SA-LLIF, 41 360-LLIF) were retrospectively analyzed. The pathway showed a direct agreement (SA-LLIF) of 100.0% and an indirect agreement (360-LLIF) of 95.1%. Clinical follow-up averaged 13.5 ± 6.5months including 4 revision surgeries in the 360-LLIF group and none in the SA-LLIF group (p = 0.117). Radiographic follow-up averaged 9.5 ± 4.3months, with no statistically significant difference in cage subsidence rate between the groups (p = 0.440). Compared to preoperative images, patients in both groups showed statistically significant changes in disk height (p < 0.001), foraminal height (p < 0.001), as well as restoration of segmental lordosis (p < 0.001 and p = 0.018). The SA-LLIF group showed shorter duration of surgery, less estimated blood loss and shorter LOS (p < 0.001). The proposed decision-making pathway provides a guide to adequately select patients for SA-LLIF. Further studies are needed to assess the external applicability and validity. Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Expandable versus static transforaminal lumbar interbody fusion (TLIF) cages: comparing radiographic outcomes and complication profiles

Background/Objectives: The treatment for lumbar disc herniation (LDH) is surgical discectomy. This surgery may enhance spinal instability and exacerbate disc degeneration. The most common treatment options include microdiscectomy (MD), interspinous process device (IPD) implantation, and percutaneous endoscopic lumbar discectomy (PELD). As few studies have compared these three procedures, this study focused on collecting data on the clinical, functional, and imaging outcomes of surgery for symptomatic LDH. Methods: This is a retrospective, transverse, and analytical study, with a total of 383 patients who received operations for symptomatic LDH between 2018 and 2022. Medical information from the charts of these patients was collected. The results were followed up on for a minimum of one year by collecting responses from several questionnaires and clinical data, including patients' scores on the visual analogue scale (VAS), Oswestry Disability Index (ODI), and symptomatic improvement score (SIS), as well as wound size, blood loss, hospital stay, postoperative disc change, and complications. Results: At the end of data collection, the VAS and ODI scores all showed significant improvement following these three procedures (p < 0.01). The SISs were all ranked as good (8.1, 8.5, and 7.9) post-surgery. PELD was a minimally invasive procedure that resulted in the smallest wound size (0.82 cm), minimal blood loss (21 mL), and a short hospital stay (4.2 days). A substantial pre-/postoperative change in disc height was noted in the MD (-17%) and PELD (-15%) groups. The complication rates were similar among the three groups (3%, 5%, and 5.6%). Conclusions: IPD implantation and PELD yielded outcomes comparable to those of conventional MD for symptomatic relief and functional recovery. Although the complication rates were similar, the postoperative complications were quite different from those of the other procedures. PELD resulted in rapid recovery and minimal invasion, and IPD implantation showed a good ability to preserve disc height and spinal stability; however, the clinical relevance of these findings in disc degeneration remains controversial.

To compare the clinical efficacy of microendoscopic discectomy + fibrous ring suture versus microendoscopic discectomy alone in the treatment of lumbar disc herniation (LDH) in young and middle-aged patients. A retrospective analysis was performed on the clinical data of 66 young and middle-aged patients with single-segment LDH diagnosed in Orthopedic Hospital of Henan Province from October 2019 to October 2022. All patients were divided into two groups: the microendoscopic discectomy + fibrous ring suture group and the microendoscopic discectomy alone group, with 33 cases in each group. The Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) scores of the two groups were recorded before surgery and six and twelve months after surgery. Both groups completed the surgery and postoperative follow-up successfully and showed no statistically significant differences in terms of incision length, duration of surgery, intraoperative blood loss and length of hospital stay (all P>0.05). VAS, ODI and JOA scores were significantly improved in both groups at 6 and 12 months after surgery compared with those before surgery (all P<0.05). The two groups were similar in terms of excellent and good rates of postoperative modified MacNab Evaluation Criteria, with no statistically significant differences. No serious complications were observed in the two groups during and after surgery. Both of the two surgical methods are effective in the treatment of LDH in young and middle-aged patients, and microendoscopic discectomy + fibrous ring suture in particular may be preferred because it results in significant improvement in patients' VAS and ODI scores.

Microendoscopic discectomy (MED) has been accepted as a minimally invasive procedure for lumbar discectomy because of the small skin incision and short hospital stay required for this surgery. However, there are few objective laboratory data to confirm the reduced systemic responses in the early phase after this procedure. In order to substantiate the reduced invasiveness of MED compared to microdiscectomy (MD) or procedures involved in one-level unilateral laminotomy, the invasiveness of each surgical procedure was evaluated by measuring serum levels of biochemical parameters reflective of a post-operative inflammatory reaction and damage to the paravertebral muscles. Thirty-three patients who underwent lumbar discectomy or one-level unilateral laminotomy (MED in 15 cases, MD in 11 cases and one-level unilateral laminotomy in 7 cases with lumbar spinal canal stenosis) were included in this study. The serum levels of C-reactive protein (CRP) and creatine phosphokinase (CPK) were measured at 24 h after operation. Interleukin-6 (IL-6) and Interleukin-10 (IL-10) were measured at 2, 4, 8 and -24 h following the surgery to monitor the inflammatory response to the respective surgery. The post-operative serum CRP levels from both the MD and MED groups were significantly lower than those from the open laminotomy group. However, there was no significant difference in these serum levels between the MED and MD groups. The levels of IL-6 and IL-10 in the MED group during the first post-operative day were also significantly lower than those in the laminotomy group. When the MED and MD groups were compared, the IL-6 levels in the MED group were lower than in MD group at 2, 4 and 8 h after surgery, but the differences were not statistically significant. However, the level was significantly lower in the MED group at 24 h after surgery. In terms of IL-10, no significant difference was noted between the MED and MD groups over the study period. The changes in serum levels of post-operative inflammatory: markers (CRP, IL-6 and IL-10) in the early phase indicated reduced inflammatory reactions in MED as well as in MD when compared with classical open unilateral laminotomy. These data draw a direct link between the lower level of the inflammatory response and reduced invasiveness of MED. However, an indicator for muscle damage (CPK) appeared not to be affected by the type of surgical procedure used to correct disc herniation.

Surgical treatment of lumbosacral foraminal stenosis requires an understanding of the anatomy of the lumbosacral area in individual patients. Unilateral facetectomy has been used to completely decompress entrapment of the L5 nerve root, followed in some patients by posterior lumbar interbody fusion (PLIF) with stand-alone cages. We assessed 34 patients with lumbosacral foraminal stenosis who were treated with unilateral facetectomy and PLIF using stand-alone cages in our center from January 2004 to September 2007. All the patients underwent follow-up X-rays, including a dynamic view, at 3, 6, 12, 24 months, and computed tomography (CT) at 24 months postoperatively. Clinical outcomes were analyzed with the mean numeric rating scale (NRS), Oswestry Disability Index (ODI) and Odom's criteria. Radiological outcomes were assessed with change of disc height, defined as the average of anterior, middle, and posterior height in plain X-rays. In addition, lumbosacral fusion was also assessed with dynamic X-ray and CT. Mean NRS score, which was 9.29 prior to surgery, was 1.5 at 18 months after surgery. The decrease in NRS was statistically significant. Excellent and good groups with regard to Odom's criteria were 31 cases (91%) and three cases (9%) were fair. Pre-operative mean ODI of 28.4 decreased to 14.2 at post-operative 24 months. In 30 patients, a bone bridge on CT scan was identified. The change in disc height was 8.11 mm, 10.02 mm and 9.63 mm preoperatively, immediate postoperatively and at 24 months after surgery, respectively. In the treatment of lumbosacral foraminal stenosis, unilateral facetectomy and interbody fusion using expandable stand-alone cages may be considered as one treatment option to maintain post-operative alignment and to obtain satisfactory clinical outcomes.

The aim of this study was to compare two approaches for the delivery of biomaterials to partially nucleotomised intervertebral discs in whole organ culture under loading. Such models can help to bridge the gap between in vitro and in vivo studies by assessing (1) suitability of biomaterial delivery and defect closure methods, (2) effect of mechanical loading and (3) tissue response. Mechanical performance of bovine discs filled with a hyaluronan-based thermoreversible hydrogel delivered through the annulus fibrosus (AF) or the bony endplate (EP) was evaluated under cyclic axial loading in a bioreactor. The loading protocol was optimised to achieve physiological disc height changes in nucleotomised discs. A loading regime of 0.06±0.02MPa, 0.1Hz, 6h daily was applied on the nucleotomised discs. Disc height and stiffness were tracked for 5days, followed by histological analyses. Creation of a defect is less demanding for AF approach, while sealing is superior with the EP approach. Dynamic compressive stiffness is reduced following nucleotomy, with no significant difference between the two approaches. Disc height loss was higher, disc height recovery was lower and region around the defect with reduced cell viability was smaller for AF-approached than EP-approached discs. Two alternative methods for biomaterial testing in whole organ culture under loading were developed. Such models bring insights on the ability of the biomaterial to restore the mechanical behaviour of the discs. From a clinical perspective, the cavity models can simulate treatment of nucleotomy after disc herniation in young patients, whereby the remaining nucleus pulposus is still functional and therefore at high risk of re-herniation, though the defect may differ from the clinical situation.

IntroductionBased on the results of long-term clinical and radiological follow-up studies of decompression and fusion with internal fixation for degenerative lumbar spondylolisthesis (DLS), we recognized that the direction of the pedicle screw affects the stability of the fixation. However, few studies have analyzed the role of pedicle screw insertion trajectory in disc height recovery after fusion. We therefore analyzed patients’ general information, clinical efficacy and sagittal, coronal and implant parameters to determine whether there is a correlation between the insertion trajectory of screws and the recovery of intervertebral space height, with the ultimate aim to provide a basis for improving the clinical efficacy and radiological outcomes of patients with DLS and to identify an optimal technique for spine surgeons that would benefit patients with spondylolisthesis.MethodsFrom May 2015 to October 2019, patients who underwent single-segment decompression and fusion with internal fixation for DLS at our department were screened for enrollment in the study. The clinical history, pre- and post-operative lumbar sagittal parameters, intervertebral height, rate of recovery from spondylolisthesis and pedicle screw angle of inpatients were recorded and followed up for at least 6 months. Clinical assessments included the Oswestry Disability Index (ODI) and the Visual Analogue Scale (VAS) for lower back and leg pain. Data on screw angle, fusion segment intervertebral space height and clinical outcome were the primary outputs. Pearson correlation and multivariate regression analyses were performed to investigate the relationship between the pedicle screw angle, the sagittal parameters of the fusion segment and clinical efficacy.ResultsA total of 50 patients were initially enrolled, two patients were lost to follow-up after 6 months, 48 patients (17 men, 31 women) were eventually enrolled, and the follow-up rate was 96%. At least 6 months after the operation, vertebral spondylolisthesis improved to varying degrees [> 80% in 17 cases (35.4%) and > 20% in 43 cases (87.5%), respectively]. Changes in disc height (DH) were significantly associated with lower pedicle screw angle, while lumbar lordosis and segment lordosis remained the same. Multivariate regression analysis showed a significant negative correlation between the upper and lower pedicle screw angles and the change in DH (P < 0.05). At 2 weeks post-operation, the VAS score for low back pain and the ODI had improved significantly compared to pre-operation (P < 0.05).ConclusionsThese results suggest that the Caudad insertion trajectory technique of pedicle screws may be an ideal alternative for the treatment of DLS.Trial Registration NumberChinese Clinical Trial Registry (ChiCTR): ChiCTR1800020368.

IntroductionAnterior cervical discectomy and fusion (ACDF) is a common surgical treatment for degenerative diseases and trauma in the cervical spine. The procedure aims to restore and maintain lordosis in the cervical spine and increase intervertebral disc height; ultimately leading to vertebral body fusion and spinal stabilisation. Polyetheretherketone cages are commonly utilised; however, new implant technologies such as 3D-printed titanium cages have emerged. There are few published reports regarding titanium cages, and therefore, this study evaluated the initial radiological outcomes of the CONDUITTM EIT Cellular Titanium Cervical Cage (DePuy Synthes, Wurmlingen, Germany). The aim is to contribute to the existing literature and establish the non-inferiority of this implant type compared to other common implants.MethodsThis study reviewed 29 patients retrospectively, who underwent 36 ACDF procedures in the Regional Spinal Unit in Northern Ireland. Radiological images were assessed at three time points: pre-operative, one-day post-operative, and follow-up (on average 6.19 months later). At each time point, intervertebral disc height, segmental Cobb angle of the operated segment, and the overall C2-C7 Cobb angle of the cervical spine were measured. To ensure the accuracy of the assessed data, all images were independently reviewed by both the author and an external observer, allowing for the calculation of the intraclass correlation coefficient for each measurement. The Wilcoxon signed rank test was used to assess the significance of changes in each radiographic variable between different time points. Spearman’s rank correlation was used to identify any relationships between the radiographic variables.ResultsIntervertebral disc height increased from an average pre-operative value of 3.79 ±1.38 mm to an average follow-up value of 5.94 ± 1.41 mm, significantly increasing by an average of 2.14 ± 1.98mm (p<0.001). Segmental Cobb Angle increased from an average pre-operative kyphotic value of -1.14 ± 8.42° to an average follow-up lordotic reading of 1.71 ± 6.28°, significantly increasing by an average of 2.86 ± 7.60° (p=0.045). Overall, the C2-C7 Cobb angle increased from an average pre-operative lordotic value of 7.36 ± 8.46° to an average follow-up lordotic value of 10.34± 12.09°, significantly increasing by an average of 2.98 ± 9.94° (p=0.021). Interestingly, all variables were the highest immediately post-operatively and then declined over the follow-up period (intervertebral disc height declined by 0.62 ± 0.98mm (<0.001), segmental Cobb angle by 0.96 ± 1.39° (p<0.007) and overall Cobb angle by 0.29 ± 8.46° (p=0.422). There was a moderate positive Spearman’s correlation coefficient of 0.498 (p=0.002) between the change in intervertebral disc height and overall C2-C7 Cobb angle. Additionally, the correlation coefficient between change in intervertebral disc height and segmental Cobb angle was 0.238 (p=0.162), indicating a non-significant weak positive relationship. The correlation coefficient between overall Cobb angle and segmental Cobb angle was -0.17 (p=0.92), indicating a very weak negative relationship, although not significant.ConclusionsTitanium cages demonstrated effectiveness in this study, showing favourable initial radiological outcomes and proving non-inferior to other cage types in this regard. Further research is needed to evaluate titanium cages, including their associated clinical outcomes, comprehensively.

Early Outcomes of Three-Dimensional–Printed Porous Titanium versus Polyetheretherketone Cage Implantation for Stand-Alone Lateral Lumbar Interbody Fusion in the Treatment of Symptomatic Adjacent Segment Degeneration

This study was performed to prospectively compare the clinical and radiographic outcomes between robot-assisted minimally invasive transforaminal lumbar interbody fusion (RA MIS-TLIF) and fluoroscopy-assisted minimally invasive transforaminal lumbar interbody fusion (FA MIS-TLIF) in patients with degenerative lumbar spinal diseases. One hundred and twenty-three patients with lumbar degenerative diseases (lumbar spinal stenosis with instability and spondylolisthesis [degenerative spondylolisthesis or isthmic spondylolisthesis]) who underwent MIS-TLIF in our hospital were included in this study. Sixty-one patients underwent RA MIS-TLIF (Group A) and 62 patients underwent FA MIS-TLIF (Group B). Group A was further divided into Subgroup AI (46 single-level procedures) and Subgroup AII (15 double-level procedures). Group B was further divided into Subgroup BI (45 single-level procedures) and Subgroup BII (17 double-level procedures). The clinical outcome parameters were the visual analog scale (VAS) score, Oswestry Disability Index (ODI) score, operative time, number of intraoperative fluoroscopies, blood loss, postoperative hospital stay, and postoperative complications. The radiographic change measures were the accuracy of screw placement, facet joint violation (FJV), fusion status, and change in disc height at the proximal adjacent segment at the 2-year follow-up. There were no significant differences in the VAS and ODI scores, blood loss, or postoperative hospital stay between Groups A and B (p > 0.05). The operative time was longer in Group A than B (p = 0.018). The operative time was longer in Subgroup AI than BI (p = 0.001). However, there was no significant difference between Subgroups AII and BII (p > 0.05). There was no significant difference in the number of intraoperative fluoroscopies for patients between Groups A and B (p > 0.05). Although the number of intraoperative fluoroscopies for patients was significantly higher in Subgroup AI than BI (p = 0.019), there was no significant difference between Subgroups AII and BII (p > 0.05). The number of intraoperative fluoroscopies for the surgeon was significantly lower in Group A than B (p < 0.001). For surgeons, the difference in the average number of intraoperative fluoroscopies between Subgroups AI and AII was 2.98, but that between Subgroups BI and BII was 10.73. In Group A, three guide pins exhibited drift and one patient developed a lateral wall violation by a pedicle screw. One pedicle screw perforated the anterior wall of the vertebral body and another caused an inner wall violation in Group B. The rate of a perfect screw position (grade A) was higher in Group A than B (p < 0.001). However, there was no significant difference in the proportion of clinically acceptable screws (grades A and B) between the two groups. The mean FJV grade was significantly higher in Group B than A (p < 0.001). During at 2-year postoperative follow-up, there was no significant difference in the fusion status between the two groups (p > 0.05); however, the decrease in disc height at the proximal adjacent segment was significantly less in Group A than B (p < 0.001). Robot-assisted percutaneous pedicle screw placement is a safer and more accurate alternative to conventional freehand fluoroscopy-assisted percutaneous pedicle screw insertion in MIS-TLIF.

Poster 40: Decreased Lower Back Pain after Noninvasive Spinal Decompression May be Due to Restored Disk Height