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Low back pain (LBP) is often associated with the degeneration of human intervertebral discs (IVDs). However, the pain-inducing mechanism in degenerating discs remains to be elucidated. Here, we identified a subtype of locally residing nucleus pulposus cells (NPCs), generated by the environmental stress in degenerating discs, that triggered the onset of discogenic LBP. Single-cell transcriptomic analysis of human tissues showed a strong correlation between this specific pain-triggering subtype and the pain conditions in human degenerated discs. Next, we recreated this pain-triggering subtype by applying known exogenous stressors to healthy NPCsin vitro. The recreated pain phenotype activated functional sensory neurons responsein vitroand induced local inflammatory responses, hyperalgesia, and mechanical sensitivity in a healthy rat IVDin vivo. Our findings provide strong evidence of a previously unknown pain-inducing mechanism mediated by NPCs in degenerating IVDs. This newly defined pathway will aid in the development of NPC-targeted therapeutic strategies for clinically unmet need to attenuate discogenic LBP.One Sentence SummaryDiscogenic low back pain can be initiated by a stress-induced subtype of nucleus pulposus cells present in human degenerating intervertebral discs

Interbody cage subsidence is a postoperative complication leading to poor outcomes after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). This study aimed to identify risk factors of cage subsidence in lumbar spinal diseases after MIS-TLIF using polyetheretherketone (PEEK) cage. In this retrospective cohort study, plain radiographs and three-dimensional computed tomography (3D-CT) performed 12 months after MIS-TLIF were evaluated, and the risk of cage subsidence was calculated with odds ratio (OR), confidence interval (CI), and logistic regression analysis. A total of 114 patients (mean age, 65 years) and 135 levels were included in this study: 80 (59.3%) with and 55 (40.7%) without cage subsidence. Multifidus atrophy showed the strongest association with PEEK cage subsidence (p 27.5 kg/m2 (OR = 4.2; p = 0.03), and titanium-coated PEEK (Ti-PEEK) cage-type (OR = 38.4, p = 0.02). In MIS-TLIF with a PEEK cage, the factors associated with an increased risk of cage subsidence were higher BMI, increased severity of multifidus muscle atrophy, Ti-coated PEEK cage-type, cage height ≥ 12 mm, use of DBM mixed autograft, and posterior cage position.

To compare patient-reported outcomes and radiographic outcomes between using polyetheretherketone (PEEK) and titanium-coated PEEK (TiPEEK) as an interbody cage in patients who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).Eighty-Six patients who underwent 1-2 levels of MIS-TLIF were randomly allocated to receive a TiPEEK or PEEK cage. Patient-reported outcomes were recorded using visual analog scale, Oswestry Disability Index, and EuroQoL-5D-5L. Postoperative radiographs and computed tomography were assessed for spinal fusion and cage subsidence.The eligible 82 patients (41 patients, 49 operated levels in TiPEEK group and 41 patients, 50 operated levels in PEEK group) were included in the final analysis. Over total follow-up, the mean difference in visual analog scale back and leg pain scores between TiPEEK versus PEEK group was -0.04 (95% confidence interval [CI], -0.5 to 0.4; P = 0.85) and -0.12 (95% CI, -0.6 to 0.3; P = 0.62), respectively. The mean difference in Oswestry Disability Index scores was -0.71 (95% CI, -3.8 to 2.4; P = 0.65), and the mean difference in EQ-5D-5 L was 0.03 (95% CI, -0.01 to 0.06; P = 0.11) in TiPEEK group versus PEEK group as a reference. TiPEEK showed significantly higher fusion rates than PEEK at 6-month (91.8% vs. 76%; P = 0.03), but no difference at 12-month postoperation. There was no significant difference in cage subsidence rates between the 2 groups.The patient-reported outcomes showed significant improvements at 6- and 12-month postoperation following MIS-TLIF; the differences in those with TiPEEK versus PEEK cages were minimal with tight CIs. Fusion rates in both groups were ≥90%, with TiPEEK cages showing higher fusion rates at 6 months after the procedure.

To compare radiographic parameters at adjacent segments before and after minimally invasive transforaminal lumbar interbody fusion and assess relationships of radiographic changes between adjacent segments and fused level.Study participants included 44 patients who underwent minimally invasive transforaminal lumbar interbody fusion at L4-5 level. Radiographic parameters at adjacent segments (L3-4 and L5-S1) and clinical parameters were reviewed.Postoperative dural sac area significantly increased in upper (mean change 8.05 mmPerforming minimally invasive transforaminal lumbar interbody fusion at the symptomatic index level does not worsen canal dimension of asymptomatic adjacent segments during short-term follow-up. It might be possible to improve canal dimension at adjacent segments by changing disc height or lordosis at the fused level via adjusting size and position of the interbody cage.

BACKGROUND: Minimally invasive transforaminal interbody fusion (MIS-TLIF) is an effective procedure for lumbar spine diseases. The procedure can be done using a surgical microscope (SM) or surgical loupes (SL) magnification. However, there are no studies that compared outcomes between using these 2 magnifying devices in the MIS-TLIF procedure. The purpose of this study was to compare clinical outcomes, perioperative complications, and radiographic parameters of MIS-TLIF using SM compared with SL magnification. METHODS: We included all patients undergoing 1-level MIS-TLIF between January 2017 and December 2019. Type of magnification (SM vs SL), operative time, blood loss, perioperative complications, cross-sectional area of the spinal canal, and fusion rates were analyzed. Clinical outcomes measurement using the visual analog scale (VAS) and Oswestry Disability Index (ODI) were compared between groups. RESULTS: A total of 100 patients had underwent MIS-TLIF (SM group: 62; SL group: 38). Operative time (SM: 182.7 ± 41.5 vs SL: 165.6 ± 32.6 minutes, P = 0.043) was significantly shorter in the SL group, with a mean difference of 17.2 minutes and a 10.4% increase in operative time between SL and SM. Blood loss (SM: 187.4 ± 176.4 vs SL: 215.6 ± 99.4 mL, P = 0.36) was not different between groups, with a mean difference of 28.2 mL. Both the SM group and SL group demonstrated no significant differences in improvement from baseline in VAS back, VAS legs, ODI score, and cross-sectional area of the spinal canal. There was also no significant difference in complication rates and fusion rates between groups. CONCLUSIONS: Our study found no difference between intraoperative use of SL compared with SM in clinical outcomes through the 12-month follow-up timepoint. However, the use of SM resulted in an increased average operative time of 17 minutes compared with the SL group. CLINICAL RELEVANCE: Intraoperative use of SM and SL magnification in MIS-TLIF provides similar outcomes except prolonged operative time in the SM group. LEVEL OF EVIDENCE: 3.

Thoracolumbar burst fracture without neurological deficit is a common spinal injury. The ideal classification for the diagnosis and the optimal management strategies, including conservative management, surgical approach, implant constructs, need for spinal fusion, and implant removal, are controversial and currently being investigated. This article reviews the current literature to provide updated evidence on these topics. Posterior ligamentous complex integrity plays an important role in the classification and decision-making process of treatment. A brace is not necessarily required in conservatively treated patients. Regarding surgical management, current evidence advocates posterior-only short segment instrumentation with intermediate screw. Cementoplasty is another option for vertebral augmentation at the fractured level. Spinal fusion is not necessary for this type of injury. Minimally invasive surgery techniques provide equivalent outcomes and can safely replace open approaches. Implant removal after stabilization may provide some benefits, especially in younger patients.

Objective. To report a nationwide survey of the endoscopic spine surgeons across Thailand. Furthermore, the survey will be focused on the perspective of experience, learning curve, motivations, and obstacles at the beginning of their practices. Materials and Methods. The online survey consisting of 16 items was distributed to spine surgeons who are performing endoscopic spine surgery in Thailand via the Google forms web-based questionnaire to investigate participants’ demographics, backgrounds, experience in endoscopic spine surgery, motivations, obstacles, and future perspectives. The data was recorded from January 7, 2020 to January 21, 2022. Descriptive statistics were used for analysis. Results. A total of 42 surveys were submitted by 6 neurosurgeons (14.3%) and 36 orthopedic surgeons (85.7%). From the surgeons’ perspective, the average number of cases that should be performed until one feels confident, consistently good outcomes, and has minimal complications was 27.44 ± 32.46 cases. For surgeons who starting the endoscopic spine practice, at least 3 workshop participation is needed. Personal interest (39 selected responses) and trending marketing or business purpose (25 selected responses) were the primary motivators for endoscopic spine surgery implementation. Lack of support (18 selected responses) and afraid of complications (16 selected responses) were pertinent obstacles to endoscopic spine surgery implementation. Conclusions. The trend of endoscopic spine surgery has continued to grow in Thailand, shown by the rate of implementation of endoscopic spine surgery reported by Thai spine surgeons. The number of appropriate cases until one feels confident was around 28 cases. The primary motivator and obstacles were personal interest and lack of support.

To compare location and amount of unremoved intervertebral disc between extreme lateral lumbar interbody fusion (XLIF) and oblique lateral lumbar interbody fusion (OLIF).Postoperative magnetic resonance images of patients who underwent XLIF and OLIF for degenerative spine diseases were reviewed. An axial cut T2-weighted image that was the middle cut of operated disc space was selected. We divided the disc area into 5 zones: central, left anterior, left posterior, right anterior, and right posterior. Disc area was measured using a picture archiving and communication system program. The angle of intervertebral cage was also measured.A total of 61 levels of XLIF from 51 patients and 62 levels of OLIF from 34 patients were included. The area of unremoved disc at left anterior, right anterior, and left posterior zones of OLIF were significantly greater than XLIF (55.7 ± 41.5 vs. 29.8 ± 33.3 mmOur study found a greater area of unremoved disc in OLIF compared with XLIF. The common locations were in the contralateral side of the surgical approach-right anterior in OLIF, and right posterior in XLIF. The greater area of the unremoved disc in the anterior zone after OLIF due to oblique corridor to disc space may cause cage malposition. Meticulous disc removal should be performed, especially in OLIF, to prevent complications.

Background The quadriceps tendon is a promising alternative graft choice for anterior cruciate ligament (ACL) reconstruction. Morphology of the graft directly affects the biomechanical properties. However, a few studies are evaluating the anatomical structures of quadriceps tendon as a graft in Asian population. Objective To define the anatomical structures of quadriceps tendon as a graft for ACL reconstruction. Methods Forty-nine quadriceps tendons were dissected and analyzed. Measurements were also done including length, width, and thickness. Results The maximum length of superficial quadriceps tendon was 63.2 ± 12.5 mm (range 37.6–83.4). The maximum length of tendon at the deepest part was 57.2 ± 11.5 (range 30.9–83.4). The maximum length of quadriceps tendon was located at 61.4% ± 13% (range 31.8–83.6) from medial edge of the patella insertion (approximately 5 mm lateral from the center of quadriceps tendon insertion). The width of quadriceps tendon at patella insertion was 42.4 ± 3.8 mm (range 33.8–50.5). The thickness of quadriceps tendon at its maximum length on patella insertion was 6.9 ± 2.0 mm (range 1.5–9.5). Positive correlation between the height of cadaver and the maximum length of quadriceps tendon was noted. Conclusions The maximum length of quadriceps tendon was located 5 mm lateral from the center of quadriceps tendon insertion. Thus, we recommend marking midline of the quadriceps tendon insertion as a medial border of the harvested graft to get maximum length of the graft. Graft length measurement using superficial anatomy should be cautioned because graft shortening might occur.

Objective To evaluate clinical and radiologic outcomes between bilateral decompression using the over-the-top technique (group 1) and unilateral decompression (group 2) in patients with claudication who underwent minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF). Methods We enrolled patients with claudication who underwent MIS-TLIF from January 2017 to June 2019. Visual analog scale (VAS) scores and Oswestry Disability Index (ODI), walking distance, and perioperative outcomes were compared between groups. Preoperative and 3-month postoperative magnetic resonance imaging assessed changes in canal cross-sectional area, foraminal height, and lateral recess area. Results Sixty-five consecutive patients with ≥1 year of follow-up were enrolled. VAS scores and ODI were not significantly different between groups (VAS and ODI, respectively, at 1 month follow-up, P = 0.62 and 0.88; 3 months follow-up, P = 0.96 and 0.53; 6 months follow-up, P = 0.10 and 0.85; and 12 months follow-up, P = 0.10 and 0.66). Operative time and blood loss between groups was not statistically significant (P = 0.43 and P = 0.55). There was also no difference in the length of hospital stay (P = 0.24). Canal dimensions increased in each group without significant differences between groups (cross-sectional area, P = 0.92; foraminal height [approach and contralateral side, respectively], P = 0.62 and 0.66; and lateral recess area [approach and contralateral side, respectively], P = 0.68 and 0.50). Conclusions A unilateral approach with ipsilateral side direct decompression and contralateral indirect decompression in MIS-TLIF is sufficient for early clinical improvement in patients with claudication.

Objective The modified iliac screw fixation technique was proposed to be an interesting alternative option for spinopelvic fixation. In this study, we describe a new minimally invasive technique for percutaneous placement of modified iliac screws. Methods A 64-year-old man with ankylosing spondylitis suffered from a 3-column fracture at the L5 vertebra without any neurologic deficit. We performed percutaneous pedicle screw fixation from L2 to S1 with additional modified iliac screws augmentation using an intraoperative navigation. We inserted both S1 pedicle screw and modified iliac screw within a stab incision on each side of the patient's back without using rod connector. Results The patient's severe low back pain subsided on the day following the operation. There was no clinical low back pain at 2-week follow-up. The 1-year follow-up x-ray showed that the fracture was healed successfully without signs of screw loosening or breakage. Conclusions The modified iliac screws can be placed safely via percutaneous approach with an intraoperative image guidance. By using this new technique, surgeons can easily adjust the screw head to align with S1 pedicle screw via the same small incision. The rod connectors are not necessary for this technique. This method also prevents the acute angle that can develop between the screw head and shaft of the screw, which is typically found in S2 alar-iliac screw technique.

STUDY DESIGN A retrospective study (level of evidence: level 4). OBJECTIVE To evaluate the radiographic outcomes after extreme lateral lumbar interbody fusion (XLIF) and oblique lateral lumbar interbody fusion (OLIF) procedures especially the effect of indirect decompression to the ligamentum flavum and to evaluate the effect of facet degeneration to the radiographic outcomes of these procedures. SUMMARY OF BACKGROUND DATA Indirect decompression via lateral lumbar interbody fusion provides spinal canal area expansion. However, the effect to the ligamentum flavum area and thickness at the operated spinal level is unclear. METHODS Thirty-five patients (57 lumbar levels) underwent XLIF or OLIF with percutaneous pedicle screw fixation (PPS) without direct posterior decompression were retrospectively studied. Radiographic parameters including ligamentum flavum area (LFA), ligamentum flavum thickness (LFT), cross-sectional area (CSA) of thecal sac, posterior disc height, foraminal height, cage alignment, and facet degeneration were measured on magnetic resonance image (MRI). Cage position was assessed with plain radiography. RESULTS All of the radiographic parameters were significantly improved. Comparing pre- and postoperative value, mean LFA decreased from 78.9 ± 24.9 mm to 66.9 ± 26.8 mm (-14.2%; P-value