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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.

In this study, the stabilities of the hinge sides of plate-augmented open-door laminoplasties based on cutting in a curved or straight line were compared using a finite element (FE) model and an experimental assessment. Using FE models generated from CT scans of a human subject, straight and curved techniques for cutting the hinge side were evaluated. Compressive forces were applied to both simulated models, and the stress distributions on the respective hinge sites were evaluated by comparing the maximum von Mises stresses. Biomechanical testing procedures were then carried out on porcine cervical vertebrae, with straight- and curved-cut groups loaded to failure, and the corresponding reaction forces on the hinge sites were recorded using a loading cell. The FE analysis results revealed no significant differences between the straight- and curved-cut groups in terms of maximum stress forces on the superior, middle, or inferior portions of the hinge sites. In the experimental study, the curved-cut group withstood higher loads to failure at the hinge site than the straight-cut group. The ability of the curved-cut laminoplasty hinges to withstand higher compressive loading to failure than straight-cut hinges suggests the potential of the proposed technique to reduce the risk of hinge fracture and displacement.

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.

The trend of minimally invasive lumbar interbody fusion is increasing, and adjacent segmental degeneration (ASD) is one of the complications of the procedures in which facet joint violation (FJV) is a cause. FJVs can occur during percutaneous instrumentation. This study aimed to identify the risk factors that affect FJV during minimally invasive lumbar interbody fusion.To identify the risk factors for FJVs and the factors that have a strong impact on the violation.Retrospective study.Patients who underwent minimally invasive lumbar interbody fusion with percutaneous screw fixation between June 2018 and December 2019.Prevalence of the FJV was reviewed by CT scans which obtained within 6 months after surgery, and the axial, coronal, and sagittal cuts of the scans were evaluated. The FJV was defined as the screw being visible in the facet joint in at least one plane of the CT scan. Radiographic parameters were measured using CT scans including diameters of the facet joints in the axial, coronal, and sagittal planes defined by the facet diameter. The facet angle (FA), the pedicle angle (PA), the screw-facet angle (SFA), the screw-endplate angle (SEA), and the superior margin of the facet joint in the sagittal plane (SD) differed from the head of the screw. At Last, the depth of back muscle was measured in the axial cut of the MRI.This study analyzed 119 patients who underwent minimally invasive lumbar interbody fusion between June 2018 and December 2019. Facet joint violation at the uppermost level was examined using CT in all dimensions. Radiographic parameters (facet diameter, facet angle, pedicle angle, screw-facet angle, screw-endplate angle, and distance between the head of the screws and the facet) were measured. BMI, age, diagnosis, and navigation assistance were included in the study. Risk factors were analyzed to determine which factors had an effect on FJV, and the cut-off was calculated for each parameter.This study included 119 patients, with a mean age of 63 years. FJV occurred in 13/119 (10.9%) patients and 15/238 (6.3%) joints, respectively. No FJV occurred in 120 joints operated with navigation-assistance and 15/178 (8.4%) joints operated without navigation (p=.01). We found an increasing proportion of violations at more caudal levels: no violations occurred in eight patients with lumbar at L1 or L2, and 1/40 (2.5%), 7/158 (4.4%), and 7/32 (21.9%) of violations occurred at L3, L4, and L5, respectively (p=.01). The diameter of the facet in the axial cut, facet angle, screw facet angle, and distance between the head of the screw and facet were statistically significant in determining the increasing rate of FJV after multivariate analysis was performed (AROC=0.9486, p≤.05). The cutoff point for each radiographic parameter were diameter of facet in the axial ≥17.5 mm, diameter of facet in coronal plane ≥19.5 mm, facet angle ≥41.5An increase in the facet diameter in the axial plane, coronal plane, facet angle, screw facet angle, and the distance between the dome of the screw and facet are risk factors for FJV. Surgeons can avoid violations when radiographic considerations are done. Careful screw placement and good entry points for instrumentation may decrease the rate of facet violation.

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.

Lumbar disc degeneration (LDD) is one of the fundamental causes of low back pain. The aims of this study were to determine serum 25-hydroxyvitamin D (25(OH)D) levels and physical performance and to investigate the relationship between serum vitamin D levels, muscle strength and physical activity in elderly patients with LDD. The participants were 200 LDD patients, including 155 females and 45 males aged 60 years and over. Data on body mass index and body composition were collected. Serum 25(OH)D and parathyroid hormone levels were measured. Serum 25(OH)D was classified into the insufficiency group

Study Design Retrospective cohort study Objectives This study aimed to report the incidence and potential risk factors of polyetheretherketone (PEEK) cage subsidence following oblique lateral interbody fusion (OLIF) for lumbar degenerative diseases. We proposed also an algorithm to minimize subsidence following OLIF surgery. Methods The study included a retrospective cohort of 107 consecutive patients (48 men and 59 women; mean age, 67.4 years) who had received either single- or multi-level OLIF between 2012 and 2019. Patients were classified into subsidence and non-subsidence groups. PEEK cage subsidence was defined as any violation of either endplate from the computed tomography scan in both sagittal and coronal views. Preoperative variables such as age, sex, body mass index, bone mineral density (BMD) measured by preoperative dual-energy X-ray absorptiometry, smoking status, corticosteroid use, diagnosis, operative level, multifidus muscle cross-sectional area, and multifidus muscle fatty degeneration were collected. Age-related variables (height and length) were also documented. Univariate and multivariate logistic regression analyses were used to analyze the risk factors of subsidence. Results Of the 107 patients (137 levels), 50 (46.7%) met the subsidence criteria. Higher PEEK cage height had the strongest association with subsidence (OR = 9.59, P < .001). Other factors significantly associated with cage subsistence included age >60 years (OR = 3.15, P = .018), BMD Conclusions Risk factors for subsidence in OLIF were age >60 years, BMD < −2.5, higher cage height, and severe multifidus muscle fatty degeneration. Patients who had subsidence had worse early (3 months) postoperative back and leg pain.

Lumbar nerve root injury is a serious complication of transpsoas lumbar interbody fusion. Researchers have reported lumbar nerve roots and psoas muscle anatomy in the supine position, but no previous studies have used prone position magnetic resonance imaging to evaluate these structures.The purpose of this study was to show the changes in the lumbar nerve roots and psoas muscle related to the lumbar intervertebral disc using supine and prone magnetic resonance imaging.Thirty volunteers without spinal or hip abnormalities were included in this observational study. Each volunteer underwent supine and prone lumbosacral magnetic resonance imaging without abdominal compression. The lumbar nerve roots, psoas muscle, aorta, superior vena cava, common iliac artery, and vein were identified at each lumbar disc level. The lumbar plexus position relative to the transpsoas working channel, psoas muscle morphology, and great vessels relative to the anterior and posterior aspects of the annulus fibrosus in the axial plane were measured by 1 observer, and intraobserver reliability was calculated.Fifteen men and 15 women were included in this study. There were no significant differences in the axial image distance of the lumbar nerve roots, psoas/disc ratio, and location of other related anatomy between the supine and prone positions. More lordosis (both upper and lower arc lordosis) was noted in the prone position (51.98° ± 10.54°) than in the supine position (42.12° ± 10.13°).Lumbar nerve roots, psoas morphology, and great vessel position were not affected by the prone position compared with the supine position.

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.

During minimally-invasive long-construct posterior instrumentation, it may be challenging to contour and place the rod as the screw heads are not visualized. To overcome this, we utilized the image data merging (IDM) facility of our spinal navigation system to visualize a coherent whole image of the construct throughout the procedure. Here, we describe this technique that was used for a patient in whom L1–L5 posterior instrumentation was performed. Using an IDM facility, screws are color coded and after placement, the final image is saved. Saved images of all previous screws are displayed and observed while placing the subsequent screws. Therefore, the entry point, depth, and mediolateral alignment of subsequent screws can be adjusted to fall in line with previous screws such that the rod can be placed without hassle. Moreover, final adjustments to the construct are kept to a minimum. The possibility of screw pullout due to force engaging the rod on poorly aligned screws is thus avoided.

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.

BACKGROUND CONTEXT Trending of minimal invasive surgery is increased and adjacent segmental degeneration is the one of the complications sequentially from the procedures which the facet joint injury is one of the causes. The patients who have ASD have vary symptoms such as back pain, neurological compression and instability and some of them required the second or third operation. The facet joint violation can occur during the instrumentation which the surgeons had known the facet joint indirectly visualization. Risk factors of the facet joint violation have the many considerations such as the patient characteristics, facet anatomy, surgical techniques and radiographic assisted. PURPOSE Identify the risk factors which have affected the facet joint violation during the minimal invasive spinal surgery. STUDY DESIGN/SETTING Retrospective study which is an analysis of 119 patients who have had the minimal invasive spinal surgery from June 2018 to December 2019. PATIENT SAMPLE A total of 119 patients who have had the minimal invasive lumbar spinal surgery with percutaneous pedicular screw placed from June 2018 to December 2019. All patients had the CT and MRI scan postoperatively within 6 months after the operation will include to our study. OUTCOME MEASURES Facet joint violation at the uppermost level was examined by the CT scan in all dimensions. The facet joint violation defined as the instrument was breeched into the facet joint. We classified these findings as in the facet violation group. The none violation was classified into non-facet violation group. Radiographic parameters (Facet diameter, facet angle, pedicle angle, screw-facet angle, screw-endplate angle and distance between head of screws and facet) were measured. BMI, age, diagnosis and navigation-assisted were included. Risk factor were analyzed and determined which factor have had an effect to the facet joint violation and scoring system for the risk factor was calculated. METHODS This study is an analysis of 119 patients who have had the minimal invasive spinal surgery from June 2018 to December 2019. Facet joint violation at the uppermost level was examined by the CT scan in all dimensions. Radiographic parameters (Facet diameter, facet angle, pedicle angle, screw-facet angle, screw-endplate angle and distance between head of screws and facet) were measured. BMI, age, diagnosis and navigation-assisted were included. Risk factor were analyzed and determined which factor have had an effect to the facet joint violation and scoring system for the risk factor was calculated. RESULTS A total of 119 patients, 36 males and 83 females, patients mean age was 63 years old, diagnosis was 38 patients had SCS, 54 patients had spondylolisthesis, 17 had HNP, 4 had degenerative scoliosis and 6 had degenerative disc disease. Facet violation was determined 1 patient at L1, 3 patients at L2, 20 patients at L3, 79 patients at L4 and 16 patients at L5. Facet joint violation occurred in 13/119(10.9%) and 15/238(6.3%) joints. No facet joint violation occurred in 60 patients who navigation-assisted was used, versus 15/178(8.4%) joints where there was no navigation(P=0.01). We found an increasing proportion of violations as the lumbar level increased: no violations occurred in 8 patients with lumbar at L1 or L2, 1/40(2.5%), 7/158(4.4%) and 7/32 (21.9%) of violations occurred at L3, L4 and L5, respectively (P=0.01). Although it was not statistically significant, the percentage of violations was higher in patients with scoliosis (12.5%) and DDD (16.7%). Diameter of facet in axial cut, facet angle, screw facet angle and distance between head of screw and facet was statistically significant to determine increasing rate of facet joint violations after multivariable analysis was done (AROC=0.9486, P≤0.05). CONCLUSIONS Increasing of the facet diameter in axial plane, facet angle, screw facet angle and distance between dome of screw and facet are one of the risk factor of facet joint violation. Surgeon can avoid the violation when the radiographic consideration was done. Careful screw placement and make the good entry points for instrumentation will decrease rate of facet violation. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT MIS-TLIF is an alternative treatment for degenerative spine disease, which aims to decompress and stabilize the most stenotic level correlating with clinical symptoms, while sparing the less severe adjacent segments. According to previous studies, interbody fusion was reported to not only affect the fused level, but also the adjacent segments. These effects might cause changes in canal dimensions at the adjacent segments, leading to unsatisfactory postoperative symptoms. PURPOSE The goal of this study was to compare the dural sac area and other canal dimension parameters on MRI at the adjacent segments before and after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF), including the change in segmental and regional parameters measured on plain radiograph. STUDY DESIGN/SETTING Retrospective cohort study King Chulalongkorn Memorial Hospital. PATIENT SAMPLE Patients who underwent MIS-TLIF at L4/5 level in King Chulalongkorn Memorial Hospital The indications for surgery were spinal canal stenosis, herniated nucleus pulposus, and spondylolisthesis grade 1-2. OUTCOME MEASURES MR image parameters: dural sac area (DSA), sagittal spinal AP diameter (SAPD), ligamentum flavum area (LFA), ligamentum flavum thickness (LFT), foraminal area (FA), foraminal height (FH), at the adjacent segments of fused level. Standing lateral plain radiograph: disc height (DH), segmental angle (SA) of adjacent segments and fused level lumbar lordosis (LL) METHODS Forty-four patients who underwent MIS-TLIF at L4/5 level were examined. The indications for surgery were spinal canal stenosis, herniated nucleus pulposus, and spondylolisthesis grade 1-2. We reviewed their standing plain radiograph and MR image parameters, including dural sac area (DSA), sagittal spinal AP diameter (SAPD), ligamentum flavum area (LFA), ligamentum flavum thickness (LFT), foraminal area (FA), foraminal height (FH), disc height (DH), segmental angle (SA), and lumbar lordosis (LL) at the adjacent segments of fused level. Disc height and segmental angle at fused level was also reviewed. All parameters were compared before, and 3 months postoperatively. RESULTS The mean (SD) pre- and postoperative DSA at upper adjacent segment was 125.12 (35.72) and 133.17 (35.07) mm2, while pre- and postoperative DSA at lower adjacent segment was 103.58 (44.32) and 117.66 (46.34) mm2 respectively. The postoperative DSA significantly increased in the upper (mean change 8.05 (95%CI 4.44-11.66) mm2, P CONCLUSIONS Adjacent segment DSA increased significantly after MIS-TLIF. In addition, other parameters representing canal dimension (SAPD, LFT) also significantly changed after the operation. Further studies are needed to assess the relationship between these changes and postoperative clinical outcomes. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Study Design: Anatomic cadaver study. Objective: Translaminar facet screw fixation supplements unilateral pedicle screw-rod fixation in minimally invasive transforaminal lumbar interbody fusion (TLIF). Various screw diameters, lengths, trajectories, and insertion points are used; however, they do not represent true screw trajectory. We aimed to evaluate lumbar laminar anatomy and suggest a safe and effective insertion point and trajectory during lumbar-translaminar facet screw fixation in an anatomic cadaver study. Methods: O-arm navigation simulating the true translaminar facet screw trajectory was used to evaluate L1-S1 in cadaveric spines. The inner and outer diameters, length, and trajectory of the screw pathway were measured along the trajectory from the spinous process base through the contralateral lamina, crossing the facet joint to the transverse process base using 2 starting points: cephalad one-third (1/3SL) and one-half (1/2SL) of the spinolaminar junction. Results: Using the 1/2SL starting point, the outer and inner lamina diameters did not differ significantly from L1-L5 (7.47 ± 1.38 to 6.7 ± 1.84 mm and 4.73 ± 1.04 to 3.86 ± 1.46 mm, respectively). Screw length (36.16 ± 4.02 to 49.29 ± 10.07 mm) and lateral angle increased (50.28° ± 8.78° to 60.77° ± 8.88°), but caudal angle decreased (16.19° ± 9.01° to 1.13° ± 11.31°). Lamina diameter and screw length did not differ with different starting points. L2-L3 caudal angles were lower in the 1/2SL starting point. Conclusion: A 36- to 50-mm translaminar facet screw—with 5.0-mm diameter for L1-L2 and 4.5-mm diameter for L3-L5—can be inserted at the middle of the spinolamina, especially during minimally invasive TLIF, with a 50° to 60° lateral angle relative to the spinous process, and a caudal angle of 16° to 1° relative to the spinolamina from L1-L5.

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.

BACKGROUND Controlling postoperative pain after spinal surgery is important for rehabilitation and patient satisfaction. Wound infiltration with local anesthetics may improve postoperative pain, but true multimodal approaches for achieving analgesia after spinal surgery remain unknown. QUESTIONS/PURPOSES In this randomized, controlled, double-blind trial after lumbar interbody fusion, we asked: (1) Does multimodal analgesia reduce VAS pain scores by a clinically important amount? (2) Does this analgesic approach reduce the amount of morphine patients consume after surgery? (3) Is this approach associated with fewer opioid-related side effects after surgery? METHODS This study included 80 adult patients undergoing lumbar interbody fusion who were randomized into two groups: A control group (n = 40) who received infiltration of the surgical incision at the end of the procedure with an injection of 0.5% bupivacaine 100 mg (20 mL) and epinephrine 0.5 mg (0.5 mL), and the multimodal group (n = 40), who received wound infiltration with the same approach but with different medications: 0.5% bupivacaine 92.5 mg (18.5 mL), ketorolac 30 mg (1 mL), morphine 5 mg (0.5 mL), and epinephrine 0.5 mg (0.5 mL). There were no between-group differences in the proportion of patients who were male, nor in the mean age, height, weight, preoperative pain score, or surgical time. All treatments were administered by one surgeon. All patients, the surgeon, and the researchers were blinded to the allocation of patients to each group. Pain at rest was recorded using the VAS. Postoperative morphine consumption (administered using a patient-controlled analgesia pump) and opiod-associated side effects including nausea/vomiting, pruritus, urinary retention, and respiratory depression were assessed; this study was analyzed according to intention-to-treat principles. No loss to follow-up or protocol deviations were noted. We considered a 2-cm change on a 10-cm scale on the VAS as the minimum clinically important difference (MCID). Differences smaller than this were considered unlikely to be important. RESULTS At no point were there between-group differences in the VAS scores that exceeded the MCID, indicating no clinically important reductions in pain associated with administering multimodal injections. The highest treatment effect was observed at 3 hours that showed only a -1.3 cm mean difference between the multimodal and the control groups (3.2 ± 1.8 versus 4.5 ± 1.9 [95% CI -1.3 to -0.3]; p < 0.001), which was below the MCID. Morphine consumption was very slightly higher in the control group than in the multimodal group (2.8 ± 2.8 versus 0.3 ± 1.0, mean difference 2.47; p < 0.001). The percentage of patients reporting opioid-related side effects was lower in the multimodal group than in the control group. The proportions of nausea and vomiting were higher in the control group (30% [12 of 40] than in the multimodal group (3% [1 of 40]; p = 0.001). All of these side effects were transient and none was severe. CONCLUSIONS Multimodal wound infiltration with an NSAID and morphine did not yield any clinically important reduction in pain or opioid consumption. Since no substantial benefit of adding these drugs to a patient's aftercare regimen was achieved, and considering the potential risks of administering opioids and NSAIDs (such as, polypharmacy in older patients, serious adverse effects of NSAIDs), we recommend against routine use of this approach in clinical practice. LEVEL OF EVIDENCE Level I, therapeutic study.

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