Risk factors of revision operation and early revision for adjacent segment degeneration after lumbar fusion surgery: a case-control study.

BACKGROUND CONTEXT: Adjacent segment degeneration (ASD) following lumbar fusion operation is common and can occur at varying timepoints after index surgery. An early revision operation for ASD, however, signifies a short symptom-free period and might increase the risk of successive surgeries. PURPOSE: We aimed to elucidate the overall risk factors associated with revision surgeries for ASD with distinct attention to early revisions. STUDY DESIGN/SETTING: Retrospective, case-control study. PATIENT SAMPLE: The study included 86 patients who underwent revision operations for ASD after lumbar fusion in the revision group and 166 patients who did not for at least 5 years after index surgery. OUTCOME MEASURES: Sagittal parameters, Pfirrmann grading, facet degeneration grading, and disc space height (DSH) of adjacent segments were assessed. METHODS: Revision operations within 5 years postsurgery were defined as early revision. We compared the revision and no-revision groups as well as the early- and late-revision groups. RESULTS: The revision group demonstrated a significantly greater preoperative C7-S1 sagittal vertical axis (SVA) (p=.001), postoperative C7-S1 SVA (p<.001), and postoperative pelvic incidence (PI)-lumbar lordosis (LL) (p<.001) than those in the no-revision group. Preoperative DSH of the proximal adjunct segment (p=.001), postoperative PI-LL (p=.014), and postoperative C7-S1 SVA (p=.037) exhibited significant association with ASD in logistic regression analysis. The early-revision group had a significantly higher patient age (p=.001) and a greater number of levels fused (p=.030) than those in the late-revision group. Multivariate Cox regression analysis demonstrated that old age (p=.045), a significant number of levels fused (p=.047), and a narrow preoperative DSH of the proximal adjacent level (p=.011) were risk factors for early revision. CONCLUSIONS: Postoperative sagittal imbalance, including significant PI-LL and C7-S1 SVA were risk factors for revision operation for ASD but not for early revision. These factors are likely to affect the long-term risk of revision operation due to ASD and thus are not considered risk factors for early revision. Narrow DSH of the proximal adjacent level increased the risks of both revision and early revision surgeries. Moreover, old age and a significant number of levels fused further increased the risk for early revision for ASD.

Shoulder balance in Lenke type 2 adolescent idiopathic scoliosis: correlations among radiological indices, cosmetic indices, and patient-reported outcomes.

OBJECTIVE: The aim of this study was to investigate the correlation between radiological indices of shoulder balance (SB) and cosmetic indices of shoulder deformity in patients with Lenke type 2 adolescent idiopathic scoliosis (AIS) and to determine the extent to which patient-reported outcomes (PROs) correlate with these measurements. Current management decisions and outcomes for SB in AIS are primarily based on radiological measurements. It is crucial to understand how these radiological parameters and cosmetic indices relate to patient satisfaction. METHODS: The authors analyzed the preoperative radiological and photographic indices of SB, along with PROs, in patients with Lenke type 2 AIS. Lateral SB parameters included the radiological shoulder height (RSH) and clavicle angle, while medial SB parameters included the first rib angle and T1 tilt angle. Photographic indices included the shoulder height angle (SHA), axilla height angle (AHA), and the left/right trapezius angle (LRTA) ratio. The authors assessed the self-image, mental health, and total score domains of the Korean version of the 22-item Scoliosis Research Society questionnaire. RESULTS: In their analysis of Lenke type 2 patients, the authors found that correlation coefficients between radiological measurements and photographic indices ranged from -0.25 to 0.47, among which only lateral SB including clavicle angle and RSH showed a significant correlation with anterior and posterior photographic indices. No statistically significant correlations were found between radiological measurements and PROs. Anterior photographic indices including SHA and AHA significantly correlated with all three PROs (p < 0.05). CONCLUSIONS: Radiological shoulder parameters did not accurately reflect the perceived SB. Anterior photographic indices were reliable for evaluating clinical SB in patients with Lenke type 2 AIS and correlated with PROs. Spine surgeons may benefit from paying more attention to anterior photographic indices when making surgical decisions regarding clinical SB.

Comparison of preemptive and preventive intravenous acetaminophen on opioid consumption in pediatrics undergoing posterior spinal fusion surgery: a randomized controlled trial.

BACKGROUND: Posterior spinal fusion (PSF), commonly used for adolescent idiopathic scoliosis (AIS), causes severe postoperative pain. Intravenous (IV) administration of acetaminophen has shown promise for opioid-sparing analgesia; however, its analgesic effect and optimal timing for its standard use remain unclear. Our study aimed to evaluate the analgesic effect and optimal timing of IV acetaminophen administration in pediatric and adolescent patients undergoing PSF and requiring adequate pain control. METHODS: This prospective, randomized, triple-blind trial was conducted in patients aged 11-20 undergoing PSF. Participants were randomized into three groups: the preemptive group (received IV acetaminophen 15 mg/kg after anesthetic induction/before surgical incision), the preventive group (received IV acetaminophen 15 mg/kg at the end of surgery/before skin closure), and the placebo group. The primary outcome was cumulative opioid consumption during the first 24 h postoperatively. RESULTS: Among the 99 enrolled patients, the mean ± standard deviation (SD) amount of opioid consumption during the postoperative 24 h was 60.66 ± 23.84, 52.23 ± 22.43, and 66.70 ± 23.01 mg in the preemptive, preventive, and placebo groups, respectively (overall P = 0.043). A post hoc analysis revealed that the preventive group had significantly lower opioid consumption than the placebo group (P = 0.013). However, no significant differences between the groups were observed for the secondary outcomes. CONCLUSIONS: The preventive administration of scheduled IV acetaminophen reduces cumulative opioid consumption without increasing the incidence of drug-induced adverse events in pediatric and adolescent patients undergoing PSF.

Novel Screw Placement Method for Extremely Small Lumbar Pedicles in Scoliosis.

Study Design: Consecutive case series. Objective: To propose a screw placement method in patients with extremely small lumbar pedicles (ESLPs) (<2 mm) to maintain screw density and correction power, without relying on the O-arm navigation system. Summary of Background Data: In scoliosis surgery, ESLPs can hinder probe passage, resulting in exclusion or substitution of the pedicle screws with a hook. Screw density affects correction power, making it necessary to maximize the number of screw placements, especially in the lumbar curve. Limited studies provide technical guidelines for screw placement in patients with ESLPs, independent of the O-arm navigation system. Methods: We enrolled 19 patients who underwent scoliosis correction surgery using our novel screw placement method for ESLPs. Clinical, radiological, and surgical parameters were assessed. After posterior exposure of the spine, the C-arm fluoroscope was rotated to obtain a true posterior-anterior view and both pedicles were symmetrically visualized. An imaginary pedicle outline was presumed based on the elliptical or linear shadow from the pedicle. The screw entry point was established at a 2 (or 10) o'clock position in the presumed pedicle outline. After adjusting the gear-shift convergence, both cortices of the transverse process were penetrated and the tip was advanced towards the lateral vertebral body wall, where an extrapedicular screw was placed with tricortical fixation. Results: Out of 90 lumbar screws in 19 patients, 33 screws were inserted using our novel method, without correction loss or complications during an average follow-up period of 28.44 months, except radiological loosening of one screw. Conclusions: Our new extrapedicular screw placement method into the vertebral body provides an easy, accurate, and safe alternative for scoliosis patients with ESLPs without relying on the O-arm navigation system. Surgeons must consider utilizing this method to enhance correction power in scoliosis surgery, regardless of the small size of the lumbar pedicle.

Does Sacral Slanting Affect Postoperative Shoulder Balance in Patients With Lenke Type 2A Adolescent Idiopathic Scoliosis?

OBJECTIVE: Even minor sacral slanting can influence T1 tilt and shoulder balance. Yet, the relationship between sacral slanting and postoperative shoulder imbalance (PSI) has not been previously explored. To determine risk factors for PSI in Lenke 2A adolescent idiopathic scoliosis (AIS) patients, with an emphasis on sacral slanting. METHODS: The study encompassed 96 consecutive patients who had undergone posterior correction and fusion surgery for Lenke type 2A AIS. Patients were grouped into PSI(+) and PSI(-) based on postoperative outcomes. Additionally, they were classified into left-sided slanting, no slanting, and right-sided slanting groups according to the degree of sacral slanting. Various radiological measures were compared. RESULTS: Patients in the PSI(+) group exhibited a smaller preoperative proximal thoracic curve and a higher main thoracic curve correction rate than those in the PSI(-) group. The presence or absence of sacral slanting did not exhibit a significant variation in PSI occurrence. However, the right-sided sacral slanting group showed a larger delta radiologic shoulder height compared to the other 2 groups (7.1 mm vs. 1.5 & 3.3 mm). CONCLUSION: Sacral slanting was not directly linked to the development of PSI. Despite the common postoperative elevation of the left shoulder, the shoulder height differences decreased over the follow-up period. Especially in cases with a right-sided tilted sacrum, the PSI demonstrated progressive improvement, with an associated increase in the rightward distal wedging angle, leading to distal adding-on.

Exploring the impact of mild-to-moderate foraminal stenosis at L5-S1 on clinical outcomes following L4-5 posterior lumbar interbody fusion.

BACKGROUND CONTEXT: Patients scheduled for L4-5 PLIF often have FS at L5-S1. However, data on the clinical and radiographic outcomes of cases with mild-to-moderate L5-S1 FS are lacking, which may affect clinical outcomes or require additional surgery after L4-5 fusion. PURPOSE: To evaluate the clinical and radiographic outcomes of L4-5 PLIF in patients with and without mild-to-moderate L5-S1 FS, with a primary focus on the association between L5-S1 FS and postoperative clinical outcomes including back pain, leg pain, and scores on the oswestry disability index (ODI) and EuroQol 5-dimension (EQ-5D). STUDY DESIGN: Retrospective comparative study. PATIENT SAMPLE: A retrospective review of patients who underwent L4-5 PLIF from 2014 to 2018. The patients were divided according to the presence of mild-to-moderate FS at L5-S1. OUTCOME MEASURES: Clinical assessment included the pain visual analog scale (VAS), ODI, and EQ-5D score. Radiographic assessments included spinopelvic parameters and grades for central and foraminal stenosis. METHODS: Clinical outcomes were assessed using validated outcome measures at preoperative, 6-month, 12-month, and 36-month follow-up visits. Radiographic evaluations were performed using preoperative and postoperative radiographs. Foraminal stenosis was assessed qualitatively using MRI with a grading system from none to severe and quantitatively by measuring changes in the foraminal area on CT. RESULTS: Among 186 patients, 55 were categorized as the FS group and 131 as the non-FS group. The FS group was older (p=0.039) and had more severe central stenosis at L5-S1 (p=0.007) as well as more severe FS at both L4-5 and L5-S1 (both p<0.001). Preoperative disc height (p<0.001), C7-S1 sagittal vertical axis (p=0.003), lumbar lordosis (p=0.005), and pelvic incidence-lumbar lordosis mismatch (p=0.026) were more aggravated in the FS group. The FS group showed inferior clinical outcomes at the final follow-up in terms of back pain (p=.010) and ODI score (p=.003). CONCLUSION: The presence of mild-to-moderate FS at L5-S1 was associated with more aggravated sagittal balance in terms of smaller preoperative disc height, larger sagittal vertical axis, smaller lumbar lordosis, and larger pelvic incidence-lumbar lordosis mismatch. Patients with L5-S1 FS also had poorer clinical outcomes including back pain and ODI score after L4-5 PLIF. Patients with L5-S1 FS need to be carefully examined before L4-5 fusion considering their adverse outcomes due to underlying degenerative changes.

Can We Control Lateral Shoulder Balance Through Proximal Thoracic Curve Correction in Lenke Type 2 Adolescent Idiopathic Scoliosis?

BACKGROUND: Proximal thoracic curve (PTC) correction has been considered to prevent lateral shoulder imbalance in Lenke Type 2 adolescent idiopathic scoliosis (AIS) patients; however, postoperative shoulder imbalance (PSI) commonly occurs despite these strategies with PTC correction. We investigated the hypothesis that PTC correction would not directly affect PSI in the majority of Lenke type 2 AIS cases. Furthermore, we investigated the risk factors for lateral PSI after corrective surgery. METHODS: This study examined the records for AIS patients with Lenke type 2 who underwent corrective surgery and followed up for >2 years. Patients were categorized into PSI (-); radiologic shoulder height (RSH)<15 mm, and PSI (+); RSH≥15 mm. Repeated measures analysis of variance was performed at preoperatively, postoperatively, 1 month, and final follow-up. Postoperative lateral shoulder imbalance was predicted by the identification of univariate analysis and multivariate analysis. RESULTS: Among the 151 patients reviewed, 29 (19.2%) showed PSI at final follow-up. Lateral shoulder balance parameters showed different directionalities between PSI (-) and (+) groups at postoperatively, 1 month, and final follow-up ( P <0.01 each). Preoperative PTC, middle thoracic curve (MTC) curve and MTC correction showed strong correlations with the RSH ( P =0.01, 0.03, and 0.04, respectively). However, PTC correction did not show a significant correlation with the RSH. Moreover, only a smaller MTC curve and larger MTC correction rate were related to lateral PSI in multivariate analysis. CONCLUSIONS: In Lenke type 2 AIS curves, the MTC curve and its correction predominantly influence lateral shoulder imbalance after corrective surgery, irrespective of the PTC correction extent. Consequently, overemphasizing the correction of the PTC curve may not necessarily lead to an improved lateral shoulder balance. When MTC curve is smaller, surgeons should be more careful for MCT overcorrection leading to a lateral shoulder imbalance. LEVEL OF EVIDENCE: Level III.

Risk Factors for Postoperative Loss of Lordosis, Cervical Kyphosis, and Sagittal Imbalance After Cervical Laminoplasty.

OBJECTIVE: A retrospective cohort study was undertaken to elucidate the risk factors of loss of cervical lordosis (LCL), kyphotic deformity, and sagittal imbalance after cervical laminoplasty. METHODS: A total of 108 patients who underwent laminoplasty to treat cervical myelopathy and were followed for ≥2 years were included. Logistic regression analysis and multiple regression analysis were performed to identify preoperative risk factors of LCL, kyphotic deformity (cervical lordosis <0°), and sagittal imbalance (sagittal vertical axis >40 mm) at postoperative 2 years. RESULTS: Within multivariate multiple regression analysis, C2-C7 lordosis (P = 0.002), and C2-C7 extension capacity (P<0.001) showed significant association with LCL. Furthermore, age (P = 0.043) and C2-C7 lordosis (P = 0.038) were significantly associated with postoperative kyphosis. Receiver operating characteristic curve analysis for postoperative kyphosis showed that preoperative C2-C7 lordosis of 10.5° had a sensitivity and specificity of 81.3% and 82.4%, respectively. Preoperative K-line tilt (P = 0.034) showed a significant association with postoperative cervical sagittal imbalance at postoperative 2 years. Receiver operating characteristic curve analysis showed that a K-line tilt cutoff value of 12.5° had a sensitivity and specificity of 78.6% and 77.7%, respectively, for predicting postoperative sagittal imbalance. CONCLUSIONS: Higher preoperative C2-C7 lordosis and less preoperative cervical extension capacity were risk factors of LCL. Small preoperative C2-C7 lordosis <10.5° and younger age were risk factors of postoperative kyphosis. Furthermore, a greater K-line tilt would increase the risk of postoperative sagittal imbalance, with a cutoff value of 12.5°.

Risk factors for postoperative complaints in patients following lumbar decompression and fusion: Analyses focusing on preoperative symptoms.

BACKGROUND: Several patients complained of residual symptoms following lumbar decompressive surgery for lumbar degenerative disease (LDD). However, few studies analyze this dissatisfaction by focusing on preoperative patients' symptoms. This study was conduct to determine the factors that could predict the patients' postoperative complaints by focusing on their preoperative symptoms. METHODS: Four hundred and seventeen consecutive patients who underwent lumbar decompression and fusion surgery for LDD were included. Postoperative complaint was defined by at least twice same complaint during the outpatient follow-up of 6,12, 18 and 24 months after surgery. A comparative analysis was performed between complaint group (group C, N = 168) and non-complaint group (group NC, N = 249). Demographic, operative, symptomatic, and clinical factors were compared between the groups by univariate and multivariate analyses. RESULTS: The main preoperative chief complaints were radiating pain (318/417, 76.2%). However, most common postoperative complaint was residual radiating pain (60/168, 35.7%) followed by tingling sensation (43/168, 25.6%). The presence of psychiatric disease (adjusted odds ratio [aOR], 4.666; P = 0.017), longer pain duration (aOR, 1.021; P < 0.001), pain to below the knee (aOR, 2.326; P = 0.001), preoperative tingling sensation (aOR, 2.631; P < 0.001), preoperative sensory and motor power decrease (aOR, 2.152 and 1.678; P = 0,047 and 0.011, respectively) were significantly correlated with postoperative patients' complaints in multivariate analysis. CONCLUSIONS: The postoperative patients' complaints could be predicted and explained in advance by checking the preoperative characteristics of patients' symptoms, including the duration and site carefully. This could be helpful to enhance the understanding of the surgical results preoperatively, which could control the anticipation of the patients.

Risk Factors for the Aggravation of Sagittal Balance After L5-S1 Posterior Lumbar Interbody Fusion.

OBJECTIVE: To identify the risk factors for the aggravation of sagittal alignment after single-level L5-S1 PLIF. METHODS: Eighty-six patients who underwent L5-S1 PLIF were divided into 2 groups according to the postoperative changes in the segmental angle (SA; group I: increase; group D: decrease). The 2 groups were compared in terms of demographic, clinical, and radiological outcomes. Multivariate logistic regression analysis was performed to identify the risk factors for aggravation of sagittal alignment. RESULTS: Of the study patients, 39 (45%) were categorized as group I and 47 (55%) as group D. The demographic and clinical parameters were not significantly different between the 2 groups. Group D showed postoperative deteriorations in the local sagittal parameters, including lumbar lordosis (LL; P = 0.034), sacral slope (P = 0.012), and pelvic tilt (P = 0.003). In contrast, group I showed improved LL after surgery (P = 0.021). Large preoperative values of lumbosacral angle (LSA; odds ratio [OR], 1.287; P = 0.001), SA (OR, 1.448; P < 0.001), and flexion LSA (OR, 1.173; P = 0.011) were independent risk factors for the aggravation of sagittal balance. CONCLUSIONS: Surgeons treating patients with large preoperative SA, LSA, and flexion LSA at L5-S1 level should be cautious of the possible aggravation of sagittal balance after L5-S1 PLIF and may consider different surgical approaches such as anterior or oblique lumbar interbody fusion.

Vertebral Body Sliding Osteotomy as a Surgical Strategy for the Treatment of Cervical Myelopathy: Outcomes at Minimum Five years Follow-up.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To evaluate the outcomes of vertebral body sliding osteotomy (VBSO) with a minimum follow-up of five years and compare the results with those of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). SUMMARY OF BACKGROUND DATA: VBSO reportedly results in fewer complications, better lordosis restoration, and faster bone union than corpectomy. Although previous studies demonstrate the outcomes of VBSO with follow-up of two years or longer, results in longer term surveillance remain unknown. METHODS: This study included 128 patients who underwent VBSO (n=38), ACDF (n=62), or ACCF (n=28) as a treatment for cervical myelopathy and was followed up for five years or more. Fusion, subsidence, C0-2 lordosis, C2-7 lordosis, segmental lordosis, C2-7 sagittal vertical axis, surgical complications, and neck pain visual analog scale, Neck Disability Index, and Japanese Orthopedic Association (JOA) scores were assessed. Comparisons between continuous variables in each group were made using independent sample t tests. For nominal variables, the Fisher exact test or the χ 2 test was used. Paired t test was used to analyze the changes in postoperative values compared with preoperative values. RESULTS: The reoperation rate (0.0%) after VBSO was significantly lower than that after ACCF (14.3%; P =0.028). VBSO had a higher fusion rate at six-month and one-year follow-up, but the fusion rate at five years (97.4%) was not significantly different from that of ACDF (85.5%; P =0.054) and ACCF (85.7%; P =0.077). Segmental lordosis at the five-year follow-up was significantly higher in the VBSO group (16.1°) than in the ACDF (11.9°; P =0.002) and ACCF (6.5°; P <0.001) groups. C2-7 lordosis at five-year follow-up was significantly higher in the VBSO group than in the ACCF group ( P =0.017). Neck pain visual analog scale, Neck Disability Index, and JOA scores and the JOA recovery rate did not show significant intergroup differences during the five-year study period. CONCLUSIONS: VBSO showed promising long-term results in terms of low revision rate, fast solid union, and effective segmental lordosis restoration when compared with other anterior reconstruction techniques.

Risk Factors and Exit Strategy of Intraoperative Neurophysiological Monitoring Alert During Deformity Correction for Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To elucidate the risk factors of intraoperative neurophysiological monitoring (IONM) alert during deformity correction surgery for adolescent idiopathic scoliosis (AIS) and to describe the outcomes of patients who underwent staged correction surgery due to IONM alert during the initial procedure. METHODS: We reviewed 1 024 patients with idiopathic scoliosis who underwent deformity correction and were followed-up for ≥1 year. The pre-and postoperative Cobb angle of the major structural curve, operative time, estimated blood loss (EBL), number of levels fused, event that caused the IONM alert, and intervention required for the recovery of the signal were recorded. Patients who received IONM alerts (alert group) and those who did not (non-alert group) during the operation were compared. RESULTS: Compared to the non-alert group, the alert group had a significantly greater preoperative Cobb angle of the major structural curve (P < .001), number of levels fused (P = .003), operative time (P < .001), and EBL (P < .001). The percentage of correction did not significantly differ between the 2 groups (P = .348). Eight patients (.8%) underwent a staged operation because the IONM signal alert hindered correction of the deformity. The percentage of correction of patients who underwent staged operation was 64.9 ± 15.1%, and no permanent neurologic deficits occurred. CONCLUSIONS: A greater magnitude of preoperative deformity and surgical extent increases the risk of cord injury identified by IONM alerts during correction of deformities in patients with AIS. However, in patients in whom the IONM alert cannot be recovered or reproduced by proceeding with deformity correction, surgeons can minimize the risk by aborting the initial procedure and completing the correction using staged operations.

Using Lordotic Cages at the L5-S1 Level Does Not Guarantee the Improvement of Sagittal Alignment in Patients Who Underwent Posterior Lumbar Interbody Fusion.

STUDY DESIGN: Retrospective comparative study. PURPOSE: This study aimed to investigate the effects of the lordotic angle of cages on sagittal alignment in patients who underwent 1- or 2-level posterior lumbar interbody fusion (PLIF), including the L5-S1 level. OVERVIEW OF LITERATURE: Few studies have addressed the effects of the lordotic angle of cages on regional and global sagittal balance in patients undergoing PLIF at the L5-S1 level. METHODS: Sixty-one patients who underwent 1- or 2-level PLIF, including the L5-S1 level, were divided into two groups based on the lordotic angle of cages (4° and 8° in 41 and 20 patients, respectively). Clinical and radiological parameters were compared. Correlation analyzes were performed to reveal the effect of flexibility and position of cages on the regional sagittal parameters. RESULTS: Pre- and postoperative clinical and radiological parameters were not different between the two groups. Although clinical outcomes improved postoperatively, sagittal parameters did not improve postoperatively in both groups. Patients who underwent 1-level PLIF at the L5-S1 level with the use of 8° cages showed no postoperative improvement (segmental angle: 16.1°-15.9°, p =0.140; lumbar lordosis: 44.8°-47.8°, p =0.740) of regional sagittal parameters. The degree of anterior location of cages showed a positive correlation with the postoperative restoration of the segmental angle (p =0.012 and p =0.050 at 1 and 2 years postoperatively, respectively). CONCLUSIONS: Clinical and radiological outcomes based on the lordotic angle of cages were not different. Even with the use of 8° cages and regardless of the more anterior position of cages, sagittal alignment did not improve in cases involving the L5-S1 level. PLIF at the L5-S1 level should be used with caution because improvement in sagittal alignment did not occur.

Floating Laminoplasty for the Treatment of Compressive Myelopathy Accompanied by C1 Posterior Ring Hypoplasia: A Technical Note and Case Series.

Posterior ring hypoplasia of the atlas (C1) is not common and in most cases is found by chance without symptoms. This disorder is sometimes accompanied by a mild C1-C2 instability or the presence of a space-occupying lesion such as ossification of posterior longitudinal ligament, pannus, or retro-odontoid pseudo-tumor, which are indications for surgery if symptomatic cord compression is present. A C1 posterior arch resection has been the procedure of choice but is associated with several fatal complications. We here present a novel posterior arch decompression technique that is relatively safer and easier and that involves mobilization and posterior translation of the posterior arch as a whole, similar to a vertebral body sliding osteotomy.

Anterior Decompression and Fusion for the Treatment of Cervical Myelopathy Caused by Ossification of the Posterior Longitudinal Ligament: A Narrative Review.

Occasionally, ossification of the posterior longitudinal ligament (OPLL) causes cord compression, resulting in cervical myelopathy. OPLL differs from other causes of cervical spondylotic myelopathy in several ways, and the surgical strategy should be chosen with OPLL's characteristics in mind. Although both the anterior and posterior approaches are effective surgical methods for the treatment of OPLL cervical myelopathy, they each have their own set of benefits and drawbacks. Anterior decompression and fusion (ADF) may improve neurological recovery, restore lordosis, and prevent OPLL mass progression. The benefits can be seen in patients with a high canal occupying ratio or kyphotic alignment. We discussed the benefits, limitations, indications, and surgical techniques of ADF for the treatment of OPLL-induced cervical myelopathy in this narrative.

Relationship Between C2 Semispinalis Cervicis Preservation and C2 Spinous Process Morphology During Cervical Laminoplasty Involving C3.

STUDY DESIGN: Retrospective study. OBJECTIVES: Due to anatomical variations in the semispinalis cervicis insertion in the C2 spinous process, complete preservation is not always possible when the C3 level is included in a cervical laminoplasty. Three-dimensional computed tomography was used to evaluate the relationship between the incidence of semispinalis cervicis injury and the C2 inter-spinous angle. METHODS: We included 95 patients who underwent a cervical laminoplasty that included a C3 laminectomy for cervical myelopathy. Patients with a C2 inter-spinous angle above and below 60° were classified into wide- and narrow-angled groups, respectively (n = 48 and n = 47). Whether the C2 semispinalis cervicis insertion was preserved, or detached and reattached was reviewed from surgical records. The pre and postoperative C2-C7 lordosis and range of motion (ROM) were measured, and clinical outcomes were obtained from the patient charts. RESULTS: The C2 semispinalis cervicis was preserved in 47 patients (97.9%) in the wide-angled group but only in 14 patients (29.8%) in the narrow-angled group (P < .001). The postoperative C2-C7 lordosis extension and ROM were significantly greater in the wide-angled (P = .048 and .036). Postoperative neck pain was significantly greater in the narrow-angled (P = .018). CONCLUSIONS: The morphology of the C2 spinous process indicates that a C2 semispinalis cervicis insertion preservation is possible during a cervical laminoplasty that includes a C3 laminectomy. A careful surgical procedure should be conducted when the C2 inter-spinous angle is above 60° to increase the likelihood of achieving this preservation and thereby obtaining a more favorable clinical outcomes.

Foraminal Restenosis After Posterior Cervical Foraminotomy for the Treatment of Cervical Radiculopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To elucidate incidence, risk factor, and clinical effect of bone regrowth after posterior cervical foraminotomy (PCF). METHODS: Ninety-eight patients who underwent PCF for the treatment of cervical radiculopathy and were followed up for >2 years were retrospectively reviewed. Foraminal dimension, sagittal gap at resected area, facet thickness, lamina length, and cervical range of motion (ROM) were measured. Neck pain visual analogue scale (VAS), arm pain VAS, and neck disability index (NDI) were recorded. Radiographic measures were compared between segments with foraminal narrowing of ≥20% at the 2-years follow-up (restenosis segments) and foraminal narrowing of <20% (patent segments). RESULTS: Sixty-nine patients with 109 segments were included. 73.4% (80/109) of foramens demonstrated foraminal narrowing and decrease of foraminal dimension of ≥20% occurred in 30.3% (30/109). Foraminal dimension at postoperative 2-days was significantly higher in the restenosis segments (P = .047). Furthermore, increase of foraminal dimension was significantly associated with foraminal restenosis of ≥20% (P = .018). Facet thickness was significantly higher in the restenosis segments compared to patent segments at postoperative 2-years follow-up (P = .038). Neck pain VAS was significantly aggravated only in the restenosis group at postoperative 2-years follow-up (P < .001). CONCLUSIONS: Foraminal narrowing commonly occurs after PCF due to bone healing. Bone growth occurs in all directions while medial facet growth contributes more to foraminal restenosis. Greater widening of foramen during PCF is a risk factor for postoperative foramen restenosis. Therefore, amount of bone resection should be kept optimal and excessive resection should be avoided to prevent foramen restenosis.

Predictable factors for aggravation of cervical alignment after posterior cervical foraminotomy.

OBJECTIVE: This study aimed to investigate the risk factors for aggravation of cervical alignment after posterior cervical foraminotomy (PCF) and to identify their relationships with kyphotic changes in cervical curvature. METHODS: Ninety-eight patients who underwent PCF for unilateral radiculopathy and received follow-up for more than 2 years were retrospectively reviewed. Segmental Cobb angle (SA), cervical Cobb angle (CA), Pfirrmann grade, foraminal stenosis, and clinical outcomes including neck pain, arm pain, and Neck Disability Index scores were assessed. Radiological and clinical outcomes were compared between groups C (control group with kyphotic change in CA < 5°) and K (kyphotic group with kyphotic change in CA ≥ 5°). Multivariate regression analysis was performed to determine the risk factors for kyphotic change ≥ 5° after PCF. RESULTS: Group K was significantly older than group C (p = 0.002) and had a higher Pfirrmann grade (p = 0.025). In group K, neck pain had significantly increased at last follow-up (p < 0.001). Multivariate linear regression analysis revealed that kyphotic changes in CA were related to older age (p = 0.016, B = 0.420) and Pfirrmann grade of the operative levels (p = 0.032, B = 4.560). Preoperative hypolordosis was not an independent risk factor for kyphotic changes in CA. Receiver operating characteristic curve analysis showed that the cutoff value for kyphotic changes in patients with CA ≥ 5° was Pfirrmann grade 3.417 (p = 0.008). CONCLUSIONS: Contrary to previous studies, preoperative hypolordosis was not a risk factor for kyphotic changes in CA after PCF. Older patients with disc degeneration of Pfirrmann grade IV or greater for should be carefully considered.

Efficacy and safety of oblique posterior endplate resection for wider decompression (trumpet-shaped decompression) during anterior cervical discectomy and fusion.

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) provides a limited workspace, and surgeons often need to access the posterior aspect of the vertebral body to achieve sufficient decompression. Oblique resection of the posterior endplate (trumpet-shaped decompression [TSD]) widens the workspace, enabling removal of lesions behind the vertebral body. This study was conducted to evaluate the efficacy and safety of oblique posterior endplate resection for wider decompression. METHODS: In this retrospective study, 227 patients who underwent ACDF for the treatment of cervical myelopathy or radiculopathy caused by spondylosis or ossification of the posterior longitudinal ligament and were followed up for ≥ 1 year were included. Patient characteristics, fusion rates, subsidence, and patient-reported outcome measures, including the neck pain visual analog scale (VAS) score, arm pain VAS score, and Neck Disability Index (NDI), were assessed. Patients who underwent TSD during ACDF (TSD group) and those who underwent surgery without TSD (non-TSD group) were compared. RESULTS: Fifty-seven patients (25.1%) were included in the TSD group and 170 patients (74.9%) in the non-TSD group. In the TSD group, 28.2% ± 5.5% of the endplate was resected, and 26.0% ± 6.1% of the region behind the vertebral body could be visualized via the TSD technique. The resection angle was 26.9° ± 5.9°. The fusion rate assessed on the basis of interspinous motion, intragraft bone bridging, and extragraft bone bridging did not significantly differ between the two groups. Furthermore, there were no significant intergroup differences in subsidence. The patient-reported outcome measures at the 1-year follow-up were also not significantly different between the groups. CONCLUSIONS: TSD widened the workspace during ACDF, and 26% of the region posterior to the vertebral body could be accessed using this technique. The construct stability was not adversely affected by TSD as demonstrated by the similar fusion and subsidence rates among patients who underwent TSD and those who did not. Therefore, TSD can be safely applied during ACDF when compressive lesions extend behind the vertebral body and are not limited to the disc space, enabling adequate decompression without disrupting the construct stability.