The Use of High-Density Pedicle Screw Construct with Direct Vertebral Derotation of the Lowest Instrumented Vertebra in Selective Thoracic Fusion for Adolescent Idiopathic Scoliosis: Comparison of Two Surgical Strategies.

STUDY DESIGN: This study was a retrospective case series. PURPOSE: This study was designed to determine whether direct vertebral rotation (DVR) of the lowest instrumented vertebra (LIV) using a high-density (HD) construct can reduce fusion segments without increasing adverse outcomes in selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: LIV DVR is used to maximize spontaneous lumbar curve correction and reduce adverse outcomes during STF for AIS. However, evidence is limited on whether LIV DVR can allow a proximally located LIV and reduce fusion segments without increasing adverse outcomes. METHODS: We reviewed consecutive patients with Lenke 1 AIS who underwent STF from 2000 to 2017. The patients were divided into two groups based on the surgical strategy used: low-density (LD) construct without DVR of the LIV (LD group) versus HD construct with DVR of the LIV (HD group). We collected data on the patient's demographic characteristics, skeletal maturity, operative data, and measured radiological parameters in the preoperative and final follow-up radiographs. The occurrence of adding-on (AO) and coronal decompensation was also determined. RESULTS: In this study, 72 patients (five males and 67 females) with a mean age of 14.1±2.3 years were included. No significant differences in the demographics, skeletal maturity, and Lenke type distribution were observed between the two groups; however, the follow-up duration was significantly longer in the LD group (64.3±25.7 months vs. 40.7±22.2 months, p <0.001). The HD group had significantly shorter fusion segments (7.1±1.3 vs. 8.5±1.2, p <0.001) and a more proximal LIV level (12.1±0.9 vs. 12.7±1.0, p =0.009). In the radiological measurements, the improvement of LIV+1 rotation (Nash-Moe scale) was significantly larger in the HD group (0.53±0.51 vs. 0.21±0.41, p =0.008). AO and decompensation occurred in 7 (9.7%) and 4 (5.6%) patients in the HD and LD groups, respectively, without any significant difference between the two groups. CONCLUSIONS: In this study, the HD group had a significantly shorter fusion level and a more proximal LIV than the LD group; however, the two groups had similar curve correction and adverse radiological outcome rates.

Radiographic Factors for Progression of Thoracolumbar Kyphosis in Achondroplasia Patients after Walking Age: A Generalized Estimating Equation Analysis.

Background: This study aimed to analyse the trends in changes of radiologic parameters according to age to predict factors affecting the progression of thoracolumbar kyphosis (TLK). Methods: Records of patients with achondroplasia were retrospectively reviewed from July 2001 to December 2020. We measured imaging parameters (T10-L2 angle, sagittal Cobb angle, width, height, and number of wedge vertebrae, and apical vertebral translation [AVT]) of 81 patients with radiographically confirmed TLK. Based on the angle on X-ray taken in 36 months, 49 patients were divided into the progression group (P group, TLK angle ≥ 20°) and resolution group (R group, TLK angle < 20°). The mean values between the groups were compared using Student t-test, and the pattern of changes in each radiologic parameter according to age was analysed using a generalized estimating equation. Results: Some imaging parameters showed significant differences according to age between P group and R group: T10-L2 angle (p < 0.001), sagittal Cobb angle (p < 0.001), AVT (p = 0.025), percentage of wedge vertebral height (WVH) (p = 0.018), and the number of severely deformed wedge vertebral bodies (anterior height less than 30% of posterior) (p = 0.037). Regarding the percentage of wedge vertebral widths (superior and inferior endplates), the difference between the two groups did not significantly increase with age, but regardless of age, it was higher in P group than in R group. Conclusions: The difference in the TLK angle between P group and R group of the achondroplasia patients gradually increased with age. Among the imaging parameters, AVT and WVH could be factors that ultimately affect the exacerbation of kyphosis as the difference between the groups increased significantly over time.

Anterior Thigh Pain Following Minimally Invasive Oblique Lateral Interbody Fusion: Multivariate Analysis from a Prospective Case Series.

Background: Oblique lateral interbody fusion (OLIF) involves the antepsoas approach and psoas major muscle (PMM) retraction to insert the interbody cage orthogonally. Therefore, OLIF is often associated with postoperative anterior thigh pain (ATP) on the approach side. However, there is limited evidence on the nature and risk factors of ATP following OLIF. Methods: Consecutive patients who planned to undergo minimally invasive OLIF and percutaneous pedicle screw instrumentation for lumbar degenerative diseases were prospectively enrolled. The visual analog scale (VAS) for ATP was recorded, and a pain map was drawn daily from the operation day to postoperative day 7 in all patients. We also prospectively collected the preoperative and intraoperative data to identify the risk factors associated with ATP. Radiologically, the total cross-sectional area (CSA), retraction length, and retraction CSA of PMM were measured from the preoperative T2-weighted axial magnetic resonance imaging scans at the L4-5 intervertebral disc level. The patients were stratified into two groups based on the experience of ATP with a VAS score of ≥ 7 at any time point. Additionally, a binary logistic regression analysis was performed to identify the associated factors. Results: The current prospective study included 92 patients (31 men, 61 women) with a mean age of 70.4 years (range, 56-86 years), who underwent OLIF at our institution. The left-side approach was used in 73 patients (79.3%), while 19 (20.7%) underwent a right-side approach. Sixty-five of the total patients (70.6%) experienced approach-side ATP to any extent during postoperative 0-7 days following OLIF. The mean pain VAS (4.4 ± 2.1) and the prevalence (57.6%) were highest at postoperative 2 days. On postoperative day 7, there were 19 patients (20.7%) who complained of residual ATP with a mean VAS of 2.6 ± 1.8. In the multivariate analysis, the PMM retraction length was significantly associated with ATP of VAS ≥ 7 (adjusted odds ratio, 2.316; p = 0.044). Conclusions: In this study, we prospectively collected and analyzed the ATP and associated factors following OLIF and identified the PMM retraction length as a potential independent risk factor for severe ATP in the immediate postoperative period following OLIF. Keywords: Anterior thigh pain, Psoas major muscle, Antepsoas, Oblique lateral interbody fusion, Genitofemoral nerve.

Involvement of L5-S1 level as an independent risk factor for adverse outcomes after surgical treatment of lumbar pyogenic spondylitis: A multivariate analysis.

PURPOSE: To identify the independent risk factors for adverse outcomes and determine the effect of L5-S1 involvement on the outcome of surgical treatment of lumbar pyogenic spondylitis (PS). METHODS: A retrospective analysis was performed for all consecutive patients who underwent surgery for lumbar PS between November 2004 and June 2020 at a single institution. The patients were divided into two groups based on the outcomes: good and adverse (treatment failure, relapse, or death). Treatment failure was defined as persistent or worsening pain with C-reactive protein (CRP) reduction less than 25% from preoperative measurement or requiring additional debridement. Relapse was defined as the reappearance of symptoms and signs with an elevated white blood cell count, erythrocyte sedimentation rate, and CRP after the first period of treatment. Binary logistic regression analyses were performed to identify the independent risk factors for adverse outcomes. RESULTS: Twenty-four (21.2%) of the 113 patients were classified as having adverse outcomes: treatment failure, relapse, and death occurred in 15, 7, and 2 patients, respectively. The involvement of L5-S1 (adjusted odds ratio [aOR] = 6.561, P = 0.004), Methicillin-resistant Staphylococcus aureus (MRSA) infection (aOR = 6.870, P = 0.008), polymicrobial infection (aOR = 12.210, P = 0.022), and Charlson comorbidity index (CCI; P = 0.005) were identified as significant risk factors for adverse outcomes. CONCLUSION: Involvement of L5-S1, MRSA, polymicrobial infection, and CCI were identified as independent risk factors for adverse outcomes after surgical treatment of lumbar PS. Because L5-S1 is anatomically demanding to access anteriorly, judicious access and thorough debridement are recommended in patients requiring anterior debridement of L5-S1.

Can Indirect Decompression Reduce Adjacent Segment Degeneration and the Associated Reoperation Rate After Lumbar Interbody Fusion? A Systemic Review and Meta-analysis.

OBJECTIVE: We sought to assess and compare the rate of adjacent segment degeneration (ASDeg), adjacent segment disease, and related reoperations between patients who underwent lumbar interbody fusion surgery using indirect or direct decompression. METHODS: On the basis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review and meta-analysis was performed to identify and analyze studies that compared the rate of ASDeg, adjacent segment disease, and related reoperations between indirect and direct decompression techniques. Indirect decompression included anterior lumbar interbody fusion, lateral lumbar interbody fusion, and oblique lateral interbody fusion, whereas direct decompression included posterior or transforaminal lumbar interbody fusion. RESULTS: Seven studies including a total of 576 patients (indirect: 314; direct: 262) were identified. The pooled rates of ASDeg were 19.4% (45/232) and 34.9% (66/189) for indirect and direct decompression, respectively. A fixed-effects model showed 0.34 times lower odds of developing ASDeg in the indirect decompression group (odds ratio = 0.34, 95% confidence interval [CI] = 0.20, 0.57). The pooled incidence of reoperation was 2.5% (8/314) and 6.1% (16/262) for indirect and direct decompression, respectively. A fixed-effects model showed 0.40 times lower odds of reoperation from ASDeg in the indirect decompression group (odds ratio = 0.40, 95% CI = 0.18, 0.89). The pooled mean difference for the segmental lordosis angle was 1.80 degrees (95% CI = 0.74, 2.86) and 7.11 degrees (95% CI = 4.47, 9.74) for total lumbar lordosis angle, favoring indirect decompression. CONCLUSIONS: Indirect decompression showed lower odds of developing ASDeg and undergoing reoperation for ASDeg after lumbar interbody fusion surgery in this meta-analysis. However, the limited number and quality of the included studies should be considered when interpreting the results.

The Effect of Adding Biological Factors to the Decision-Making Process for Spinal Metastasis of Non-Small Cell Lung Cancer.

Molecular target therapies have markedly improved the survival of non-small cell lung cancer (NSCLC) patients, especially those with epidermal growth factor receptor (EGFR) mutations. A positive EGFR mutation is even more critical when the chronicity of spinal metastasis is considered. However, most prognostic models that estimate the life expectancy of spinal metastasis patients do not include these biological factors. We retrospectively reviewed 85 consecutive NSCLC patients who underwent palliative surgical treatment for spinal metastases to evaluate the following: (1) the prognostic value of positive EGFR mutation and the chronicity of spinal metastasis, and (2) the clinical significance of adding these two factors to an existing prognostic model, namely the New England Spinal Metastasis Score (NESMS). Among 85 patients, 38 (44.7%) were EGFR mutation-positive. Spinal metastasis presented as the initial manifestation of malignancy in 58 (68.2%) patients. The multivariate Cox proportional hazard model showed that the chronicity of spinal metastasis (hazard ratio (HR) = 1.88, p = 0.015) and EGFR mutation positivity (HR = 2.10, p = 0.002) were significantly associated with postoperative survival. The Uno's C-index and time-dependent AUC 6 months following surgery significantly increased when these factors were added to NESMS (p = 0.004 and p = 0.022, respectively). In conclusion, biological factors provide an additional prognostic value for NSCLC patients with spinal metastasis.

Risk factors for postoperative ileus after oblique lateral interbody fusion: a multivariate analysis.

BACKGROUND CONTEXT: Oblique lateral interbody fusion (OLIF)-has become a widely used, efficient surgical tool for various degenerative lumbar conditions. Postoperative ileus (POI) is a relatively common complication after anterior lumbar interbody fusion due to the manipulation of the intestine during the surgical approach. However, to our knowledge, little is known about POI following OLIF even though it also involves bowel manipulation during a surgical procedure. PURPOSE: To assess the incidence of POI and identify independent risk factors for POI development after OLIF. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: All consecutive patients who underwent OLIF and percutaneous pedicle screw instrumentation from August 2012 until October 2019 at a single institution OUTCOME MEASURES: Patient demographics (sex, age, body weight, height, and body mass index), comorbidities (diabetes mellitus, gastroesophageal reflux disease, antithrombotic medication, previous abdominal surgery, and previous lumbar surgery), and perioperative details (preoperative diagnosis, number of levels fused, inadvertent endplate fracture during cage insertion, type of interbody graft, intraoperative estimated blood loss, duration of surgery and anesthesia, the amount of intraoperative remifentanil and propofol used as anesthetic agents, the total postoperative retroperitoneal closed-suction drainage output, and the cumulative opioid dosage administered in the first 72 hours postoperatively). METHODS: POI was defined as 2 or more of the following at 72 hours postoperatively: (1) ongoing nausea or vomiting postoperatively, (2) the absence of flatus over last 24-hour period, (3) inability to tolerate an oral diet over last 24-hour period, (4) ongoing abdominal distention postoperatively, and (5) radiological confirmation. The subjects were divided into 2 groups: patients with POI and those without POI. Binary logistic regression analyses were performed on demographics, comorbidities, and perioperative factors to identify independent risk factors for POI. RESULTS: Eighteen (3.9%) of 460 patients experienced POI after OLIF and percutaneous pedicle screw instrumentation. Patients with POI had a significantly longer postoperative length of hospital stay than those without POI (8.61 ± 2.66 vs 6.48 ± 2.64, p = .001). Multivariate logistic regression analysis identified inadvertent endplate fracture (adjusted odds ratio = 6.017, p = .001) and the amount of intraoperative remifentanil (adjusted odds ratio = 1.057, p = .024) as independent risk factors for the occurrence of POI following OLIF. CONCLUSION: This study identified inadvertent endplate fracture and the amount of intraoperative remifentanil as independent risk factors for the development of POI after OLIF.

Treatment Strategy for Metastatic Spinal Tumors: A Narrative Review.

Metastatic spinal tumors are common, and their rising incidence can be attributed to the expanding aging population and increased survival rates among cancer patients. The decision-making process in the treatment of spinal metastasis requires a multidisciplinary approach that includes medical and radiation oncology, surgery, and rehabilitation. Various decision-making systems have been proposed in the literature in order to estimate survival and suggest appropriate treatment options for patients experiencing spinal metastasis. However, recent advances in treatment modalities for spinal metastasis, such as stereotactic radiosurgery and minimally invasive surgical techniques, have reshaped clinical practices concerning patients with spinal metastasis, making a demand for further improvements on current decision-making systems. In this review, recent improvements in treatment modalities and the evolution of decision-making systems for metastatic spinal tumors are discussed.