Impact of spinal injury on mortality in patients with major trauma: A propensity-matched cohort study.

Major trauma is defined as a significant injury or injury that has the potential to be life-threatening and is quantitatively identified as an injury severity score (ISS) >15. Spinal injuries are common in patients with major trauma; however, because spinal injury is not independently included in the ISS calculation, the impact of spinal injury on mortality in patients with major trauma has not been fully elucidated. The purpose of this study is to identify the association between spinal injury and mortality in patients with major trauma. From January 1, 2016, to December 31, 2020, retrospective analysis was conducted on 2893 major trauma adult patients admitted to a level 1 trauma center. There were 781 patients in the spinal injury group and 2112 patients in the group without spinal injury. After matching the 2 groups 1:1, we compared injury mechanism, mortality, cause of death, intensive care unit length of stay (ICU LOS), and duration of ventilator use between spinal injury group and matched cohorts. Falls and traffic accidents were the most common injury mechanisms in the spinal injury group and the matched cohort, respectively. The mortality was significantly lower in the spinal injury group compared with the matched cohort (4.0% vs 7.9%, P = .001), and the ICU LOS was longer than the matched cohort (8.8 ± 17.4 days vs 7.2 ± 11.7 days, P = .028). In the spinal injury group, multiple organ failure (MOF) was the most common cause of death (41.9%), while that in the matched cohort was central nervous system (CNS) damage (61.3%). In patients with major trauma, spinal injury may act as a shock absorber for internal organs, which is thought to lower the mortality rate.

Cage Obliquity and Radiological Outcomes in Oblique Lateral Interbody Fusion.

STUDY DESIGN: Retrospective radiological study. OBJECTIVE: This study aimed to examine whether cage obliquity affects radiological outcomes in oblique lateral interbody fusion (OLIF). SUMMARY OF BACKGROUND DATA: The OLIF cage enters the disk space in the oblique direction and is then turned to the true orthogonal orientation. However, orthogonal cage placement is often hindered by cage rotation limitations. Few studies have examined the degree of cage obliquity and its effects in OLIF. MATERIALS AND METHODS: This study involved 171 levels in 118 consecutive patients who underwent OLIF between L2-L3 and L4-L5 with a minimum two-year follow-up. Cage obliquity was divided into three groups on postoperative axial computed tomography images; cage obliquity <10° (group 1), cage obliquity ≥10° and <20° (group 2), and cage obliquity ≥20° (group 3). The radiological outcomes included anterior/posterior disk height, intervertebral disk angle, foraminal height, fusion, and cage subsidence. Postoperative complications related to cage obliquity were examined. RESULTS: The mean cage obliquity of the 171 cages was 11.3±6.9°. Cage obliquity was greater at the L4-L5 level (13.4±6.4°) than at other levels (L2-L3 and L3-L4: 6.5±7.0° and 10.1±6.2°, respectively) ( P <0.05). There were no significant differences in radiological outcomes among the groups. There were two cases of postoperative contralateral neurological symptoms in group 3. CONCLUSIONS: Our study showed that the orthogonal cage rotation in OLIF achieved adequate lateral cage placement. Although accurate cage rotation can be limited at the lower lumbar segments, radiological outcomes were not affected by cage obliquity.

Risk factors for nonunion in oblique lateral interbody fusion.

BACKGROUND: Compared with posterior interbody fusion techniques, oblique lateral interbody fusion (OLIF) offers a larger fusion bed with greater intervertebral space access, use of larger cages, more sufficient discectomy, and better end-plate preparation. However, the fusion rate of OLIF is similar to that of other interbody fusions. This study aimed to examine the factors associated with nonunion in OLIF. METHODS: This study examined 201 disc levels from 124 consecutive patients who underwent OLIF for lumbar degenerative diseases with 1-year regular follow-up. Demographic and surgical factors were reviewed from the medical records. Radiological factors measured were sagittal parameters, intervertebral disc angle (DA) before surgery and at the final follow-up, presence of vertebral end-plate lesions, and cage subsidence. Multivariable logistic regression analysis was performed to identify the factors associated with nonunion. RESULTS: Among the 201 discs, 185 (92.0%) achieved union at 1-year followed up. Smoking, surgery at the L5-S1 level, not performing laminectomy, and a large intervertebral DA were factors associated with nonunion in OLIF (all P < 0.05). Multivariable logistic regression analysis showed two independent variables (surgery at L5-S1 level and not performing laminectomy) as risk factors for nonunion in OLIF. CONCLUSIONS: Not performing laminectomy and surgery at the L5-S1 level were risk factors for nonunion in OLIF. To reduce the nonunion rate, surgeons should consider additional stabilization strategies for the L5-S1 OLIF and perform laminectomy.

Covalent and Oriented Immobilization of Antibodies through Systematic Modification of Photoactivatable RNA Hybrid Aptamers.

We report a covalent and well-oriented strategy of immobilization of antibodies using photoactivatable Fc-binding RNA aptamers (FcBAs). We prepared several types of FcBAs that were further modified with photoaffinity probes (i.e., benzophenone or diazirine), and evaluated the binding capabilities and the photo-crosslinking efficiency of them via pull-down assays and fluorescence analyses, respectively. Initial moderate photo-crosslinking efficiency (Kd ∼ 110 nM) was substantially improved by multivalent association of FcBAs and structural modification of FcBAs. For a conceptual proof, covalent crosslinking of human IgG on FcBA-tethered solid chips was fabricated and investigated by scanometry, which eventually proved real applicability of the present scheme toward immunoassays.

A Modified Anterior Column Realignment With Partial Anterior Longitudinal Ligament Release in Oblique Lateral Interbody Fusion.

STUDY DESIGN: Retrospective radiological analysis. OBJECTIVE: To demonstrate the radiological outcome after a modified anterior column realignment (mACR) with partial anterior longitudinal ligament (ALL) release in oblique lateral interbody fusion (OLIF). SUMMARY OF BACKGROUND DATA: Anterior column realignment (ACR) remains a powerful sagittal correction technique in minimally invasive adult spinal deformity surgery and is often combined with posterior column osteotomy (PCO) to achieve more lordosis. OLIF is ideal for ACR because the anterior-to-psoas corridor typically involves the anterolateral half of the disk. METHODS: This study included 112 operated disk levels of 101 consecutive patients who underwent OLIF between L2-L3 and L4-L5 using a 12° lateral cage. The mACR was performed at 73 (65.2%) levels with 30% to 50% sectioning of the ALL. Each operated level was grouped according to the mACR and additional PCO as: (1) no mACR, OLIF only (n=39); (2) mACR with no PCO (n=18); (3) mACR with grade 1 PCO (n=27); (4) mACR with grade 2 PCO (n=22); or (5) mACR with grade 3 PCO (n=6). RESULTS: At the last follow-up, the mean disk lordotic angles were 10.9±2.9°, 12.6±3.0°, 13.3±3.9°, 16.7±3.2°, and 16.8±2.4° in the no mACR, mACR with no PCO, mACR with grade 1 PCO, mACR with grade 2 PCO, and mACR with grade 3 PCO groups, respectively ( P <0.001). The mean increases in disk lordotic angle were 5.8±4.1°, 12.1±6.1°, 13.5±8.7°, 15.8±6.7°, and 17.9±6.2° in each group, respectively ( P <0.001). CONCLUSIONS: ACR can be performed with partial ALL release under direct vision in OLIF without deep dissection into the ventral disk space. The mACR in OLIF is a simple, safe, and effective technique for anterior column lengthening. LEVEL OF EVIDENCE: 4.

Influence of Vascular Anatomy on the Radiologic Outcomes in Oblique Lateral Interbody Fusion at L5-S1.

STUDY DESIGN: This was a retrospective study. OBJECTIVE: The objective of this study was to evaluate whether the anatomy of the left common iliac vein (LCIV) affects the radiologic outcomes in oblique lateral interbody fusion (OLIF) at L5-S1. SUMMARY OF BACKGROUND DATA: Upward mobilization and retraction of the LCIV is an essential technique in OLIF at L5-S1. However, mobilization of the LCIV is sometimes difficult and may affect the surgical outcomes in OLIF at L5-S1. METHODS: This study involved 52 consecutive patients who underwent OLIF at L5-S1 and had >1-year regular follow-up. The configuration of LCIV on preoperative axial magnetic resonance images of the lumbar spine was categorized into 3 types according to the difficulty of mobilization: type I (no requirement for mobilization), type II (potentially easy mobilization), and type III (potentially difficult mobilization). Radiologic parameters included anterior/posterior disk heights (ADH/PDH), disk angle (DA), cage migration, cage subsidence, cage position, and fusion rate at L5-S1. Intraoperative/perioperative events associated with OLIF at L5-S1 were reviewed. Radiologic outcomes among the LCIV types were compared. RESULTS: There were 19 men and 33 women with a mean age of 62.8±9.7 years. The mean follow-up duration was 24.8±15.5 months. The LCIV anatomy was type I in 25 (48.1%) patients, type II in 14 (26.9%), and type III in 13 (25.0%). The mean ADH increased from 7.0±4.7 to 16.9±4.1 mm at the last follow-up (P<0.001), and the mean PDH increased from 2.7±1.7 to 4.9±1.6 mm (P<0.001). The mean DA increased from 5.4±5.4 to 16.9±6.5 degrees (P<0.001). There were no significant differences in ADH, PDH, and DA at the last follow-up among the LCIV types. Two (3.8%) major and 2 (3.8%) minor LCIV injuries were identified, all of which had a type III LCIV. CONCLUSIONS: OLIF at L5-S1 showed favorable radiologic outcomes regardless of the LCIV anatomy. However, type III LCIV patients had a high rate of intraoperative vascular injury.

Factors Affecting Slip Reduction in Oblique Lumbar Interbody Fusion With Posterior Fixation for Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective case series. OBJECTIVES: Reduction of translational/angular slip is a favorable radiological result in spinal fusion for degenerative spondylolisthesis, although its clinical significance remains controversial. Few studies have investigated slip reduction and associated factors in oblique lumbar interbody fusion (OLIF) for degenerative spondylolisthesis. METHODS: This study involved a retrospective analysis of 56 operated levels of 52 consecutive patients who underwent OLIF for degenerative spondylolisthesis and had more than 1-year of regular follow-up. Translational/angular slip, anterior/posterior disc height, and spinopelvic parameters were measured preoperatively, postoperatively at 6-weeks, and at the last follow-up. Demographic, radiological, and surgical parameters were analyzed to determine factors associated with the amount of slip reduction. RESULT: The mean follow-up duration was 30.4 ± 12.9 months (range, 12 to 61). The mean decrease in translational slip was 5.7 ± 2.1 mm (13.6 ± 5.5%) and the mean increase in angular slip was 7.9 ± 7.1° at the last follow-up (both P < 0.001). The amount of slip reduction was greater in female sex, age < 65 years, use of a 12° cage, cage position from the anterior disc margin of < 7 mm, and cases with posterior decompression (laminectomy with inferior facetectomy). CONCLUSIONS: OLIF showed satisfactory translational/angular slip reduction in degenerative spondylolisthesis. Surgical techniques for optimal reduction include the use of a large angle cage, anterior cage placement, and resection of the inferior facet.

Effectiveness of supplemental screw fixation for the prevention of anterior cage migration in oblique lateral interbody fusion at L5-S1.

BACKGROUND: The anterior cage at L5-S1 segment is more vulnerable to anterior migration because of the sacral slope, the greater disc angle (DA), the higher shear force, and the weaker pedicle screw fixation at S1. We hypothesized that a supplemental screw (SS) fixation is effective for the prevention of anterior cage migration in oblique lateral interbody fusion (OLIF) at L5-S1. METHODS: This study involved 61 consecutive patients who underwent OLIF at L5-S1 and had more than 1-year regular follow-up. In the first 35 cases, the anterior cage was fixed with pedicle screws only (non-SS group). In the remaining 26 cases, the anterior cage was fixed with a SS and pedicle screws (SS group). Radiological parameters including anterior disc height (ADH), posterior disc height (PDH), DA, cage migration, cage subsidence, and fusion rate at L5-S1 were compared between the two groups. RESULT: Of the total 61 patients, fifteen (24.6%) patients had an anterior cage migration of >2 mm and six (9.8%) patients had an anterior cage migration of >5 mm. Baseline demographic characteristics were similar between the two groups. The mean cage migration was 2.0 ± 3.1 mm in the non-SS group and 0.9 ± 0.9 mm in the SS group (P = 0.038). Thirteen (37.1%) patients had a cage migration of >2 mm in the non-SS group, while only two (7.7%) had a cage migration of >2 mm in the SS group (P = 0.002). There were no significant differences in the ADH, PDH, DA, cage subsidence, and fusion rate between the two groups (all P > 0.05). There was no SS-related complication in the SS group. CONCLUSIONS: SS fixation in front of the anterior L5-S1 cage is simple, safe, and effective for the prevention of anterior cage migration in OLIF at L5-S1.

Is the Severity of Cervical Foraminal Stenosis Related to the Severity and Sidedness of Symptoms?

(1) Background: Cervical foraminal stenosis (CFS) is a common cause of axial neck and arm pain. The aim of this study was to determine the relationship between the severity of CFS and clinical symptoms in terms of severity and sidedness. (2) Methods: We retrospectively reviewed 75 consecutive patients with degenerative CFS. We graded 900 foramina from C3-4 to T1-2 using Park's grading system. We collected visual analogue scale (VAS) and neck disability index (NDI) values from the neck and both arms. We analyzed the relationships with CFS grades and total number. We defined four types of left/right dominance of CFS (none, left-dominant, right-dominant, and both) by comparing left and right sides using total counts and maximal grade of CFS, respectively. We compared arm pain sidedness (no arm pain, left-only, right only, and bilateral) among different left and right CFS dominance types. (3) Results: Mean neck and left and right arm VAS scores were 4.4 ± 2.5, 4.9 ± 1.6, and 4.6 ± 2.0, respectively. The mean total NDI was 16.0 ± 8.0. The CFS grade at C3-4 and total count were correlated with neck VAS. Arm VAS was also correlated with CFS grade and total counts. Total NDI score was not correlated with radiological parameters. The presence and sidedness of arm pain were significantly different between left and right CFS dominance groups divided by total count of grade 2 and 3 CFS. (4) Conclusions: The CFS grade and total count were correlated with neck and arm VAS. Arm pain occurred more frequently on the side with more grade 2 and 3 CFS.

Rapid Progression to Complete Paraplegia After Electroacupuncture in a Patient With Spinal Dural Arteriovenous Fistula: A Case Report.

Spinal dural arteriovenous fistula (SDAVF) usually has an insidious clinical course, but 5-15% of the cases have acute exacerbations. In some cases, there is an abrupt progression to paraplegia following an epidural injection or anesthesia. Electroacupuncture is a form of acupuncture that applies a small electrical current to needles inserted at specific points in the body. It is widely used for its analgesic effect on back pain. In this study, we report a rare case of SDAVF in which the symptoms of a patient worsened rapidly to complete paraplegia within a few hours after applying electroacupuncture to his back. A 49-year-old man had rapid progression to complete paraplegia within a few hours of electroacupuncture on his back. MRI showed SDAVF and worsening of cord signal change. An emergency operation was performed to ligate the SDAVF. The patient was able to walk 1 month post-operatively. Most of the neurological deficits had disappeared by 1 year post-operatively, with normalization of MRI. Our case emphasizes that SDAVF patients should be careful when exposed to any circumstances that might affect the circulation around the dural arteriovenous fistula, such as electroacupuncture. Patients should also be warned in advance about the possibility of rapid exacerbation of neurological symptoms. Regardless of the severity of the neurological symptoms, immediate treatment is essential for recovery and a better outcome.

Factors affecting disc angle restoration in oblique lateral interbody fusion at L5-S1.

BACKGROUND CONTEXT: Optimal restoration of the L5-S1 disc angle (DA) is an important surgical goal in spinal reconstructive surgery. Anterior approach is beneficial for L5-S1 DA reconstruction and fusion. However, factors associated with a greater DA restoration in oblique lateral interbody fusion (OLIF) at L5-S1 have not been studied. PURPOSE: This study aimed to identify factors that aid in achieving a greater DA in OLIF at L5-S1. STUDY DESIGN/SETTING: A retrospective analysis. PATIENT SAMPLE: This study involved 61 consecutive patients who underwent OLIF at L5-S1 for lumbar degenerative disease and were followed for more than 1 year. Patients with incomplete data or posterior column osteotomy at L5-S1 were excluded. OUTCOME MEASURES: The L5-S1 DA was measured preoperatively, postoperatively, and at the last follow-up on standing lateral lumbar radiographs. The associations between demographics and/or surgical and/or radiological factors and the L5-S1 DA at the last follow-up were analyzed using multiple regression analysis. METHODS: Demographics and surgical factors were reviewed from the medical records with respect to age, sex, body mass index, bone mineral density, diagnosis, surgery level, cage parameters (cage lordotic angle and height), laminectomy performed and/or not performed, estimated blood loss, operative time, configuration of the left common iliac vein. Radiological factors were measured with respect to sagittal parameters, the L5-S1 disc parameters, and the postoperative cage parameters. RESULTS: The mean preoperative DA at L5-S1 was 5.4±5.0°, which increased to 18.9±5.6° postoperatively (p<.001) and was maintained as 16.5±5.9° at the last follow-up (p<.001). The preoperative DA, end plate lesions, anterior spur, facet joint osteoarthritis, or cage position at L5-S1 did not affect the DA at the last follow-up (all p>.05). Multiple regression analysis showed four independent variables, including increased age, increased cage lordotic angle, laminectomy performed, and absence of cage subsidence as the factors associated with the greater DA at L5-S1. CONCLUSIONS: OLIF at L5-S1 showed favorable DA restoration regardless of the preoperative conditions. To achieve a greater DA, surgeons should try to distract the anterior disc space for insertion of a larger lordotic cage. Laminectomy during posterior fixation is recommended for achieving additional DA restoration.

Comparison of surgical outcomes between oblique lateral interbody fusion (OLIF) and anterior lumbar interbody fusion (ALIF).

OBJECTIVE: Although oblique lateral interbody fusion (OLIF) utilizes the similar approach in anterior lumbar interbody fusion (ALIF), OLIF is essentially a lateral lumbar interbody fusion (LLIF). Therefore, OLIF may have advantages in LLIF that the lateral cage can achieve greater restoration of the disc height and angle. We aimed to compared the surgical outcomes between OLIF and ALIF. METHODS: This study involved 47 consecutive patients who underwent a single-level OLIF and 45 consecutive patients who underwent a single-level ALIF at L2-L5 levels. Radiological measurements included the changes of anterior/posterior disc height, coronal/sagittal disc angle, foramen cross-sectional area (CSA), cage position from the anterior margin of the lower vertebra, fusion rate, and cage subsidence using the serial radiographs and computed tomography preoperatively and at the postoperative 1-year follow-up. Clinical outcomes were assessed by visual analog scale (VAS) for back/leg pain, Oswestry disability index (ODI), and the occurrence of perioperative complications. RESULTS: The baseline radiological and clinical parameters were similar between the OLIF and ALIF groups (all P > 0.05). At postoperative 1 year, the mean anterior disc height was higher in the OLIF group than the ALIF group (11.4 ±â€¯1.9 mm vs. 9.6 ±â€¯2.6 mm, P = 0.021). The mean sagittal disc angle was also greater in the OLIF group than the ALIF group (10.9 ±â€¯4.4° vs. 8.9 ±â€¯5.8°, P < 0.001). The mean cage position was 5.8 ±â€¯2.1 mm in the OLIF group and 8.7 ±â€¯2.3 mm in the ALIF group (P <  0.001). There was no difference in the postoperative changes of coronal disc angles, foramen CSA, fusion rate, cage subsidence, VAS for back/leg pain, ODI, and the occurrence of perioperative complications between the OLIF and ALIF groups (all P > 0.05). CONCLUSIONS: OLIF showed a greater increase in disc height and segmental lordosis than ALIF with comparable complications. OLIF is a meaningful progress from ALIF.

Prospective investigation of Oswestry Disability Index and short form 36 subscale scores related to sagittal and coronal parameters in patients with degenerative lumbar scoliosis.

PURPOSE: This study investigated relationships of Oswestry Disability Index (ODI) and Short Form 36 (SF-36) total and subscale scores with global spinal parameters in patients with degenerative lumbar scoliosis (DLS). METHODS: This was a prospective single-center study of 126 consecutive patients with DLS. Disability was evaluated using the ODI and SF-36 total and subscale scores. Sagittal and coronal parameters were measured. Pearson's correlation analysis was performed to determine relationships between disability and radiographic parameters. RESULTS: The study population included 76 women and 15 men (mean age, 70.2 ± 8.4 years). Mean Cobb angle was 18.9° ± 8.0°. The ODI total score and SF-36 physical component score were only correlated with coronal parameters. ODI pain intensity, personal care, lifting, sitting, and sex life domains were only correlated with coronal parameters. The walking, standing, social life, and traveling domain scores were correlated with coronal and sagittal parameters. The SF-36 bodily pain and vitality domain scores were only correlated with coronal parameters. The SF-36 physical function domain score was correlated with both coronal and sagittal parameters. Among the clinical and radiographic parameters, the personal care score and the coronal vertical-axis had the strongest correlation (r = 0.425), although the r2 value was only 0.18. CONCLUSIONS: ODI total score and most of the subscale scores were significantly, but weakly correlated with coronal parameters. Sagittal parameters were only correlated with some of the ODI and SF-36 subscale scores. Analysis using ODI and SF-36 subscale scores may aid in understanding and treatment of disability in patients with DLS.

Vascular anatomy and surgical approach in oblique lateral interbody fusion at lumbosacral transitional vertebrae.

BACKGROUND: Oblique lateral interbody fusion (OLIF) at lumbosacral junction is typically performed on the central window between the bifurcations of iliac vessels. However, the central window of lumbosacral transitional vertebrae (LSTVs) is usually obstructed by the iliocaval venous structures. We aimed to describe the vascular anatomy and surgical approach in OLIF at LSTVs compared with those in OLIF at typical L5-S1 junction. METHODS: Sixty-eight consecutive patients who underwent OLIF at lumbosacral junction were included. Of these, 31 patients had LSTVs and 37 patients had typical L5-S1 junction. The position of the iliocaval junction and the configuration of the left common iliac vein were compared using the preoperative CT and MR images of the lumbar spine. The surgical approach and intraoperative vascular findings were analyzed. RESULTS: Almost 70% of LSTVs had the iliocaval junction at low or very low position. Mobilization of left common iliac vein for central window was potentially difficult in almost 74% of OLIF at LSTVs while it was not required or was potentially easy in almost 80% of OLIF at typical L5-S1. Vascular injury was identified in 2 (6.5%) patients with OLIF at LSTVs and in 3 (8.1%) patients with OLIF at typical L5-S1 junction (P = 0.904). CONCLUSIONS: In our series, OLIF at LSTVs was performed through lateral window in 93.5% of the cases. Preoperative evaluation of the iliocaval junction using CT/MR of lumbar spine was reliable and valid in the determination of OLIF approach at lumbosacral junction.

The Impact of Vertebral End Plate Lesions on the Radiological Outcome in Oblique Lateral Interbody Fusion.

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: Vertebral end plate (EP) lesions include Modic changes, Schmorl's nodes, EP erosion, EP sclerosis, and so on. While previous studies have mostly focused on the association between vertebral EP lesions and low back pain, few studies evaluated the influence of vertebral EP lesions on the radiological outcomes in lumbar interbody fusion. METHODS: This study included a total of 125 operated disc levels from 86 consecutive patients who underwent a 1- or 2-level oblique lateral interbody fusion (OLIF) and had more than 1-year regular follow-up. The presence of vertebral EP lesions, changes in disc heights/angle, cage subsidence, and fusion grade were examined. The associations between vertebral EP lesions and radiological parameters were analyzed. RESULT: The presence of Modic changes, Schmorl's node, EP cartilage erosion, and EP sclerosis were found in 72 (57.6%), 26 (20.8%), 31 (24.8%), and 44 (35.2%) disc levels, respectively. The mean anterior disc height increased from 6.9 ± 3.8 mm to 13.1 ± 2.7 mm (P < .001) and the mean segmental angle increased from 2.9° ± 5.8° to 9.2° ± 4.8° (P < .001) at the last follow-up. The overall fusion rate was 98.4% (123/125) and cage subsidence rate was 7.2% (9/125). All radiological parameters and cage subsidence rate were not different regardless of vertebral EP lesions. CONCLUSIONS: Vertebral EP lesions did not affect the overall radiological outcome in 1- or 2-level OLIF. These results come from the stable contact between lateral cage and peripheral rim of vertebral EP.

Radiological Risk Factors for Neurological Deficits After Traumatic Mid and Low Lumbar Fractures.

STUDY DESIGN: Retrospective study. OBJECTIVE: We identified radiological risk factors for neurological deficits in mid and low lumbar spinal fractures. SUMMARY OF BACKGROUND DATA: Although numerous studies have focused on radiological risk factors for neurological deficits in spinal cord injury or thoracolumbar junction area fractures, few have examined mid and low lumbar fractures at the cauda equina level. METHODS: We retrospectively reviewed 71 consecutive patients who suffered acute traumatic mid and low lumbar fractures (L2-L5) corresponding to the cauda equina level, as confirmed on magnetic resonance imaging. We defined a neurological deficit as present if the patient had any sensory or motor deficit in the lower extremity or autonomic system at the initial assessment. Various computed tomography parameters of canal stenosis, vertebral body compression, sagittal alignment, interpedicular distance, and presence of vertical laminar fractures were analyzed as independent risk factors to predict neurological deficits using multivariate logistic regression analyses. RESULTS: At the initial assessment, 31 patients had neurological deficits. Fracture level, AO fracture type, canal encroachment ratio, vertebral compression ratio, interpedicular distance ratio, and presence of a vertical laminar fracture were significantly associated with the presence of neurological deficits (all P < 0.05). Multivariate logistic regression identified fracture level, canal encroachment ratio (adjusted odds ratio [aOR] 1.072, 95% confidence interval [CI] 1.018-1.129), and vertebral compression ratio (aOR 0.884, 95% CI 0.788-0.992) as independent predictors of a neurological deficit. Receiver operating characteristic curve analyses revealed that only the canal encroachment ratio had good discriminatory ability (area under the curve 0.874, 95% CI 0.791-0.957), and the optimal cutoff was 47% (canal diameter 6.6 mm) with 90.3% sensitivity and 80% specificity. CONCLUSION: The canal encroachment ratio was most strongly associated with neurological deficits in traumatic mid and low lumbar fractures, with an optimal cutoff of 47%. LEVEL OF EVIDENCE: 4.

Degenerative changes of sagittal alignment in patients with Roussouly type 1.

STUDY DESIGN: A cross-sectional radiological study. OBJECTIVES: We aimed to examine the degenerative changes of sagittal alignment in patients with Roussouly type 1. Roussouly type 1 is unique in shape, characterized by short lumbar lordosis (LL) with the apex at L5 and thoracolumbar kyphosis (TLK). Because of the unique shape of sagittal alignment and the small pelvic incidence (PI) in Roussouly type 1, the degenerative changes of sagittal alignment may differ. METHODS: A total of 145 patients with Roussouly type 1 were recruited and distributed into three age groups; Group I (N = 40) were young patients (20-40 years of age), Group II (N = 47) were middle-aged patients (45-60 years of age), and Group III (N = 48) were elderly patients (>65 years of age). Sagittal parameters including sagittal vertical axis (SVA), PI, pelvic tilt (PT), L1S1 LL, L4S1 LL, thoracic kyphosis (TK), and TLK were measured using Surgimap® software. The occurrence of lumbar retrolisthesis was also examined. RESULTS: The SVA, PI, PT, L1S1 LL, L4S1 LL, TK, and TLK in group I were - 25.9° ± 23.4 mm, 37.1° ± 5.3°, 10.3° ± 5.5°, 42.7° ± 8.8°, 35.5° ± 6.9°, 29.5° ± 23.5°, and 9.7° ± 5.9°, respectively. Among the Groups I, II, and III, there was a stepwise increase in the SVA, PT, TLK, and lumbar retrolisthesis (all P < 0.001). The PI, L4S1 LL, and TK were identical among the three groups. CONCLUSIONS: Degenerative changes of Roussouly type 1 include increase in the SVA, PT, TLK, and lumbar retrolisthesis, while the PI, L4S1 LL, and TK remain unchanged. LEVEL OF EVIDENCE: Level IV.

Triangular Osteosynthesis Using an S1 Pedicle Screw and S2 Alar Iliac Screw for a Unilateral Vertically Displaced Sacral Fracture.

BACKGROUND: Managing unilateral vertically displaced sacral fractures remains a challenge. A triangular osteosynthesis (TOS), which involves fixing the fractured sacrum using unilateral spinopelvic fixation and a supplemental ilio-sacral screw, continues to gain popularity as it facilitates early mobilization and improves the long-term outcome. However, it has limitations, such as destruction of the L5-S1 joint, the need for additional removal surgery, and an increased risk of infection due to the large incision. An S1 pediculoiliac construct was proposed to overcome this limitations. Its use also has complications, however, including a painful hardware prominence due to the traditional iliac screw, excessive soft tissue retraction, and limited reduction capability. CASE DESCRIPTION: A 20-year-old woman fell from a height of 6 meters and sustained a vertical shear type sacral fracture on the left side with substantial vertical displacement. We reduced and fixed the fracture using a TOS using an S1 pedicle screw and an S2 alar iliac screw (S2AIS). The patient was allowed immediate weight-bearing as tolerated. We achieved good reduction and union with a small vertical incision, without the destruction of L5-S1 joints, a symptomatic implant prominence, or wound complications. CONCLUSIONS: For unilateral vertically unstable sacral fractures, TOS using S1 pedicle screws and S2AIS is safe and has the advantage such as maintaining mobility in the lumbar pelvic region, small size wounds, and reduced soft tissue damage, and it may have a potentially low infection rate. Further studies are needed to determine the specific indications and validate the effectiveness of this procedure.