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.

Preoperative Factors on Loss of Range of Motion after Posterior Cervical Foraminotomy.

Background and Objectives: Posterior cervical foraminotomy (PCF) aims to resolve cervical radiculopathy while preserving range of motion (ROM). However, its effectiveness in maintaining ROM is uncertain. This study investigates the changes in ROM after PCF and identifies preoperative factors that influence ROM reduction post surgery. Materials and Methods: This retrospective cohort study included patients treated at our hospital from August 2016 to September 2021. Clinical outcomes were assessed using the visual analog scale (VAS) for neck and arm pain and the neck disability index (NDI). Radiological outcomes included the segmental angle (SA), cervical angle (CA), C2-C7 SVA, Pfirrmann grade, extent of facetectomy, foraminal stenosis, and ROM. Patients were categorized into two groups based on segmental ROM changes: decreased (Group D) and maintained (Group M). Radiological and clinical outcomes were compared between the groups. Univariate and multivariate regression analyses were performed to identify risk factors for ROM loss after PCF. Results: 76 patients were included: 34 in Group D and 42 in Group M, with no demographic differences. Preoperatively, Group D had significantly larger flexion segmental and cervical angles than Group M (segmental, p < 0.001; cervical, p = 0.001). Group D also had a higher Pfirrmann grade (p = 0.014) and more bony bridge formations (p = 0.004). While no significant differences were observed in arm pain VAS and NDI scores, Group D exhibited worse neck pain VAS at the last follow-up (p = 0.03). Univariate linear regression indicated that preoperative segmental ROM (p < 0.001, B = 0.82) and bony bridge formation (p = 0.046, B = 5.33) were significant predictors of ROM loss post PCF. Conclusions: Patients with higher preoperative flexion angles and Pfirrmann grades at the operative level are at an increased risk for ROM loss and neck pain and often exhibit bony bridge formation. Accounting for these factors can improve surgical planning and patient outcomes.

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.

The medial window technique as a salvage method to insert C2 pedicle screw in the case of a high-riding vertebral artery or narrow pedicle: a technical note and case series.

PURPOSE: To describe the safety and feasibility of C2 medial window screw (C2MWS) as an alternative salvage method for C2 pedicle screws in cases of high-riding vertebral artery (HRVA) or narrow pedicle. METHODS: The C2MWS technique involves screw insertion by intentionally breaching the medial cortex of the pedicle to avoid vertebral artery injury. Twelve patients who underwent C2 screw insertion via the C2MWS were retrospectively reviewed. C2MWS was indicated in cases of high-riding vertebral artery (HRVA) or narrow pedicle (pedicle width ≤ 4 mm). The width of the canal breach by screw, vertebral artery groove (VAG) breach, solid fusion, neck pain visual analogue scale (VAS) score, and Japanese Orthopedic Association (JOA) score were assessed as outcome measurements. RESULTS: C2MWS was indicated due to both HRVA and narrow pedicle for 11 screws, narrow pedicle for one screw, and HRVA for two screws. No screw VAG breach or vertebral artery injury was noted postoperatively. The mean width of canal breach was 2.9 ± 1.3 mm. There were no cases demonstrating neurologic deterioration, and 11 patients (91.7%) demonstrated solid fusion at 1-year follow-up. Furthermore, neck pain VAS and JOA scores significantly improved after the surgery. CONCLUSIONS: The C2MWS technique can provide 3-column fixation while reliably avoiding VA injury. C2MWS could be considered as a salvage alternative method when the insertion of C2 pedicle screw is complicated by HRVA or a narrow pedicle, while there is a need to provide firmer fixation strength than that provided by pars or translaminar screws.

functional mobility tests for evaluation of functionalities in patients with adult spinal deformity.

STUDY DESIGN: Retrospective cohort study. BACKGROUND: Current evaluation of patients with adult spinal deformity (ASD) is mainly based on radiographic parameters derived from X-rays. However, due to their static nature, X-rays fall short of assessing the dynamic functionalities including balance, gait, and the risk of falling. This study aimed to determine the functionalities of ASD patients by measuring functional mobility tests (FMTs) and compared the relationships between patient-reported outcomes (PROs) with FMTs and radiographic parameters to determine whether FMTs are useful evaluation tools for the evaluation of patients with ASD. METHODS: This age- and sex-matched case-control study included 66 patients with ASD and 66 patients with LSS, all of whom were scheduled to undergo spinal surgery. All patients were evaluated with four FMTs including alternate step test (AST), six-meter walk test (SMT), sit-to-stand test (STS), and timed up and go test (TUGT). Correlations of the PROs with FMTs and static radiographic parameters were analyzed. RESULTS: The baseline characteristics were not significantly different between the two groups. However, compared with patients with LSS, those with ASD showed significantly poorer performance on all four FMTs, spending significantly more time performing the SMT, STS, and TUGT (P = 0.046, 0.045, and 0.015, respectively). The results of the four FMTs were significantly correlated with the ODI (Oswestry Disability Index) scores only in the ASD group and not in the LSS group. CONCLUSIONS: FMTs were appropriate tools for assessing the dynamic functionalities of patients with ASD. FMTs might play a bridging role between static radiographic parameters and subjective PROs when treating patients with ASD.

Evaluation of Carpal Arch Widening and Outcomes After Carpal Tunnel Release.

PURPOSE: The purpose of this study was to compare the carpal arch widths between baseline and 6 months after open carpal tunnel release, and to determine whether any increase in the carpal arch width was associated with clinical outcomes of surgery. METHODS: We measured carpal arch widths in standardized carpal tunnel radiographs before, and 6 months after, open carpal tunnel release in 76 patients with carpal tunnel syndrome. Clinical outcomes were assessed for grip strength change and perceived disability using the Disabilities of the Arm, Shoulder, and Hand questionnaire at 6-month follow-up. We correlated the clinical outcomes with carpal arch width changes. RESULTS: The mean change of the carpal arch width was 1.8 mm (standard deviation, 1.4 mm; range, -0.3 to 5.2 mm). There was no significant correlation between the amount of carpal arch width widening and the clinical outcomes in terms of grip strength change and the Disabilities of the Arm, Shoulder, and Hand scores. CONCLUSIONS: This study found that the change of carpal arch width was minimal at 6 months after open carpal tunnel release, and that the increase, if any, was not associated with clinical outcomes such as grip strength change or the Disabilities of the Arm, Shoulder, and Hand scores. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Comparison of Tibial Tunnel Techniques in Posterior Cruciate Ligament Reconstruction: C-Arm Versus Anatomic Fovea Landmark.

PURPOSE: To evaluate the accuracy of the posterior cruciate ligament (PCL) fovea landmark against conventional fluoroscopic pin placement retrospectively using 3-dimensional computed tomography (3D CT). METHODS: This retrospective comparison focused on the tibial tunnel locations determined in consecutive 26 patients using the fluoroscopic imaging technique (group I) and in consecutive 23 patients using the PCL fovea landmark technique without the help of the fluoroscopy (group II) for tibial tunnel formation. The 3D surface-modeled CT images that appropriately located the position of the PCL fovea on the tibial plateau were used. Ratios between total length of the fovea and length of the tunnel center from the medial border (coronal) and posterior edge (sagittal) were evaluated. RESULTS: The ratios between sagittal tunnel length and total sagittal length for groups I and II were 35.4% ± 12.2% and 44.1% ± 23.1%, respectively (P = .07). The ratios between the coronal tunnel lengths and total coronal lengths for groups I and II were 47.3% ± 9.2% and 57.3% ± 18.1%, respectively: group II showed a more laterally positioned tibial tunnel than did group I (P = .03). CONCLUSIONS: A more laterally located tibial tunnel was produced using the PCL fovea landmark technique. However, the differences in centers were small and probably not clinically relevant. Therefore, the PCL fovea landmark technique might be an alternative method to the fluoroscopic imaging technique for locating the anatomic tibial tunnel during transtibial PCL reconstruction. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

An Algorithmic Roadmap for the Surgical Management of Degenerative Cervical Myelopathy: A Narrative Review.

Degenerative cervical myelopathy (DCM) is a leading cause of disability, and its surgical management is crucial for improving patient neurological outcomes. Given the varied presentations and severities of DCM, treatment options are diverse. Surgeons often face challenges in selecting the most appropriate surgical approach because there is no universally correct answer. This narrative review aimed to aid the decision-making process in treating DCM by presenting a structured treatment algorithm. The authors categorized surgical scenarios based on an algorithm, outlining suitable treatment methods for each case. Four primary scenarios were identified based on the number of levels requiring surgery and K-line status: (1) K-line (+) and ≤3 levels, (2) K-line (+) and ≥3 levels, (3) K-line (-) and ≤3 levels, and (4) K-line (-) and ≥3 levels. This categorization aids in determining the appropriateness of anterior or posterior approaches and the necessity for fusion, considering the surgical level and K-line status. The complexity of surgical situations and diversity of treatment methods for DCM can be effectively managed using an algorithmic approach. Furthermore, surgical techniques that minimize the stages and address challenging conditions could enhance treatment outcomes in DCM.

Relationship of the Iliac Crest Height with Subsidence After Oblique Lateral Interbody Fusion at L4-5: A Quantitative and Categorical Analysis.

Background: This study aimed to evaluate the impact of iliac crest height on clinical and radiological outcomes following oblique lateral interbody fusion (OLIF) at the L4-5 level. Methods: Data of patients who underwent single-level OLIF at the L4-5 level for degenerative spinal stenosis were retrospectively analyzed. The patients were categorized into three groups based on their iliac crest height measured relative to the L4 and L5 pedicles. Categorical and quantitative analyses, including univariate and multivariate logistic regressions, were performed to identify subsidence predictors. Clinical outcomes, including visual analog scale scores for back and leg pain, were assessed over a minimum 2-year follow-up. Results: No significant differences in cage obliquity were observed across the iliac crest height groups (axial angles, p = 0.39; coronal angles, p = 0.79). However, subsidence was significantly more common in patients with higher iliac crest heights, particularly at crest level III, where the subsidence rate reached 43% (p = 0.01). Subsidence was predominantly associated with damage to the L5 endplate, which occurred in 83% of subsidence cases at crest level III. A cutoff value of 12 mm for iliac crest height, above which the risk of subsidence significantly increased, was identified (AUC = 0.688, p = 0.042). Conclusions: Iliac crest height is a critical factor for predicting subsidence following OLIF at the L4-5 level. Surgeons should consider alternative strategies and meticulous preoperative planning in patients with an iliac crest height ≥ 12 mm to reduce the risk of adverse outcomes. Further studies are needed to validate these findings and to explore their long-term implications.

Impact of the Disc Vacuum Phenomenon on Surgical Outcomes in Lumbar Spinal Stenosis: A Comparative Study between Endoscopic Decompression and Minimally Invasive Oblique Lateral Interbody Fusion.

Objective: This study investigated the influence of the vacuum phenomenon (VP) on surgical outcomes in patients with lumbar spinal stenosis, comparing minimally invasive oblique lateral interbody fusion (MIS OLIF) and endoscopic decompression. Methods: A cohort of 110 patients diagnosed with lumbar spinal stenosis underwent either endoscopic decompression or MIS OLIF. Patients were classified into two groups based on the presence or absence of the VP on preoperative CT scans, non-VP (n = 42) and VP (n = 68). Radiologic and clinical outcomes, including back and leg pain assessed using the visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the EuroQol-5 Dimension (Eq5D), were compared pre- and postoperatively over a 2-year follow-up period. Results: Preoperatively, the VP group exhibited significantly greater leg pain (p = 0.010), while no significant differences were observed in back pain or the ODI between the groups. In the non-VP group, decompression and fusion yielded similar outcomes, with decompression showing a better ODI score at 1 month (p = 0.018). In contrast, in the VP group, patients who underwent fusion showed significantly improved long-term leg pain outcomes compared to those who underwent decompression at both 1-year (p = 0.042) and 2-year (p = 0.017) follow-ups. Conclusions: The VP may indicate segmental instability and may play a role in the persistence of radiculopathy. Fusion surgery appears to offer better long-term relief in patients with the VP, whereas decompression alone is a viable option in non-VP cases. These findings suggest that the VP may be a useful factor in guiding surgical decision-making.

Meta-Analysis on Efficacy and Complications of Bone Morphogenetic Protein-2 for Posterior Fusion of Cervical Spine.

OBJECTIVE: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is effective for promoting robust fusion for long-level cervical deformity and revision surgeries. However, only a few studies have reported its efficacy and complications in posterior cervical fusion (PCF). METHODS: Therefore we evaluated the efficacy and complications of rhBMP-2 application in PCF surgery by searching 3 electronic databases (PubMed, Cochrane Database, and EMBASE) for studies that evaluated the use of rhBMP-2 in PCF. Five studies (1 prospective and 4 retrospective) were included in the meta-analysis. RESULTS: The quality of each study was assessed, and data on pseudarthrosis, wound infection, neurologic, and immediate medical complications were extracted and analyzed. We found that the use of rhBMP-2 in PCF showed significant benefits in terms of pseudarthrosis and no significant increases in the risk for neurologic and immediate medical complications regardless of the dose. However, high-dose (>2.1 mg/level) rhBMP-2 was a risk factor for wound infection after PCF. CONCLUSIONS: Our meta-analysis of the currently available literature suggests that patients with PCF may benefit from BMP-2 usage without increasing the risk of complications. However, dose control and containment are important to ensure a low risk of complications.

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.

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.

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.

The Perioperative Effects of Preoperative Radiotherapy in Metastatic Spinal Tumor Patients.

OBJECTIVE: Radiotherapy is one of the important treatment options for metastatic spinal tumors but is not the definite intervention in all cases, as there are patients who still require surgical treatment because of severe pain or neurologic events after this treatment. We evaluated the perioperative effects of preoperative radiotherapy in these cases as a future guide for surgeons on critical considerations in this period. METHODS: We included 328 patients in this study who had undergone decompression and fusion surgery for metastatic spinal tumors. Patients who underwent surgery with preoperative radiotherapy were designated as the radiotherapy group (group RT, n = 81), and cases of surgery without preoperative radiotherapy were assigned to the non-radiotherapy group (group nRT, n = 247). We compared the demographic, intraoperative, and postoperative factors between these 2 groups. RESULTS: In terms of intraoperative factors, statistically significant differences were evident in operation time, estimated blood loss, and transfusion (RT vs. nRT: 188.1 ± 80.7 minutes vs. 231.2 ± 106.1 minutes, 607.2 ± 532.7 mL vs. 830.1 ± 1324.7 mL, and 30.9% vs. 43.3%, P < 0.001, P < 0.031, and P < 0.048, respectively). With regard to postoperative factors, the incidence of infection, wound problems, and local recurrence were statistically higher in group RT (RT vs. nRT: 6.2% vs. 0.8%, 12.3% vs. 0.8%, 23.4% vs. 13.7%, P = 0.004, P < 0.001, and P = 0.038, respectively). CONCLUSIONS: Preoperative radiotherapy has the intraoperative advantages of reducing bleeding and shortening the operating time, but postoperative caution is needed because of the possibility of infection, wound problems, and local recurrence increases.

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.

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.

Atrophy of the Posterior Cricoarytenoid Muscle as an Indicator of a Recurrent Laryngeal Nerve Injury History Before Revision Anterior Cervical Spine Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVES: In our recent study, we observed some cases of symptomatic normal vocal cord motility instead of asymptomatic vocal cord palsy (VCP) in preoperative laryngoscopy of a revision anterior cervical spine surgery (ACSS) cohort. We assumed the intrinsic muscle atrophy caused by recurrent laryngeal nerve injury could cause vocal cord-related symptoms. Thus, radiological examinations were reviewed in relation to the posterior cricoarytenoid (PCA) muscle, one of the intrinsic muscles. METHODS: We retrospectively analyzed 64 patients who underwent a revision ACSS. Patients with vocal cord-related symptoms were classified as symptomatic group (group S, n = 11), and those without symptoms as asymptomatic group (group AS, n = 53). The bilateral size and signal intensity of the PCA muscles in these patients were measured in the axial view with preoperative computed tomography (CT) and magnetic resonance imaging (MRI) evaluations. Since the size and signal intensity values were different on each image, the ratios of the contralateral and ipsilateral muscle values were analyzed for each modality. RESULTS: There was no VCP on laryngoscopy study. However, the mean ratio of the PCA muscle size on CT was 1.40 ± .37 in group S and 1.02 ± .12 in group AS (P = .007). These values on the MRI were 1.49 ± .45 in group S and 1.02 ± .14 in group AS, which was also a significant difference (P = .008). CONCLUSIONS: Evaluating the size of the PCA muscle before revision ACSS may predict a previous recurrent laryngeal nerve injury. Careful planning for the appropriate approach should be undertaken if vocal cord-related symptoms and atrophy of PCA muscle are evident.

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.

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.