Full-endoscopic versus microscopic spinal decompression for lumbar spinal stenosis: a systematic review & meta-analysis.

BACKGROUND CONTEXT: Symptomatic lumbar spinal stenosis is routinely treated with spinal decompression surgery, with an increasing trend towards minimally invasive techniques. Endoscopic decompression has emerged as a technique which minimizes approach-related morbidity while achieving similar clinical outcomes to conventional open or microscopic approaches. PURPOSE: To assess the safety and efficacy of endoscopic versus microscopic decompression for treatment of lumbar spinal stenosis. STUDY DESIGN: Systematic review and meta-analysis. METHODS: A systematic review on randomized and nonrandomized studies comparing endoscopic versus microscopic decompression was conducted, in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Treatment effects were computed using pairwise random-effects meta-analysis. Risk of bias was assessed using the Cochrane Risk-of-bias and ROBINS-I tools for randomized and nonrandomized trials respectively. Quality of the overall body of evidence was appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. RESULTS: A total of 19 primary references comprising 1,997 patients and 2,132 spinal levels were included. Endoscopic decompression was associated with significantly reduced intraoperative blood-loss (weighted mean differences [WMD]=-33.29 mL, 95% CI:-51.80 to -14.78, p=.0032), shorter duration of hospital stay (WMD=-1.79 days, 95% CI: -2.63 to 0.95, p=.001), rates of incidental durotomy (RR = 0.63, 95% CI: 0.43 to 0.91, p=.0184) and surgical site infections (RR=0.23, 95% CI: 0.10 to-0.51, p=.001), and a nonsignificant trend towards less back pain, leg pain, and better functional outcomes compared to its microscopic counterpart up to 2-year follow up. CONCLUSIONS: Endoscopic and microscopic decompression are safe and effective techniques for treatment of symptomatic lumbar spinal stenosis. Prospective studies of larger power considering medium to long-term outcomes and rates of iatrogenic instability are warranted to compare potential alignment changes and destabilization from either techniques.

Deep learning assessment compared to radiologist reporting for metastatic spinal cord compression on CT.

Introduction: Metastatic spinal cord compression (MSCC) is a disastrous complication of advanced malignancy. A deep learning (DL) algorithm for MSCC classification on CT could expedite timely diagnosis. In this study, we externally test a DL algorithm for MSCC classification on CT and compare with radiologist assessment. Methods: Retrospective collection of CT and corresponding MRI from patients with suspected MSCC was conducted from September 2007 to September 2020. Exclusion criteria were scans with instrumentation, no intravenous contrast, motion artefacts and non-thoracic coverage. Internal CT dataset split was 84% for training/validation and 16% for testing. An external test set was also utilised. Internal training/validation sets were labelled by radiologists with spine imaging specialization (6 and 11-years post-board certification) and were used to further develop a DL algorithm for MSCC classification. The spine imaging specialist (11-years expertise) labelled the test sets (reference standard). For evaluation of DL algorithm performance, internal and external test data were independently reviewed by four radiologists: two spine specialists (Rad1 and Rad2, 7 and 5-years post-board certification, respectively) and two oncological imaging specialists (Rad3 and Rad4, 3 and 5-years post-board certification, respectively). DL model performance was also compared against the CT report issued by the radiologist in a real clinical setting. Inter-rater agreement (Gwet's kappa) and sensitivity/specificity/AUCs were calculated. Results: Overall, 420 CT scans were evaluated (225 patients, mean age=60 ± 11.9[SD]); 354(84%) CTs for training/validation and 66(16%) CTs for internal testing. The DL algorithm showed high inter-rater agreement for three-class MSCC grading with kappas of 0.872 (p<0.001) and 0.844 (p<0.001) on internal and external testing, respectively. On internal testing DL algorithm inter-rater agreement (κ=0.872) was superior to Rad 2 (κ=0.795) and Rad 3 (κ=0.724) (both p<0.001). DL algorithm kappa of 0.844 on external testing was superior to Rad 3 (κ=0.721) (p<0.001). CT report classification of high-grade MSCC disease was poor with only slight inter-rater agreement (κ=0.027) and low sensitivity (44.0), relative to the DL algorithm with almost-perfect inter-rater agreement (κ=0.813) and high sensitivity (94.0) (p<0.001). Conclusion: Deep learning algorithm for metastatic spinal cord compression on CT showed superior performance to the CT report issued by experienced radiologists and could aid earlier diagnosis.

Ambulatory uniportal versus biportal endoscopic unilateral laminotomy with bilateral decompression for lumbar spinal stenosis-cohort study using a prospective registry.

BACKGROUND: Endoscopic spine surgery has been established as a practical, minimally invasive technique for decompression in patients with lumbar spinal stenosis. However, there remains a paucity of studies prospective cohort study comparing uniportal lumbar endoscopic unilateral laminotomy with bilateral decompression and unilateral biportal endoscopic unilateral laminotomy with bilateral decompression with open spinal decompression-both viable techniques with satisfactory clinical outcomes in the treatment of lumbar spinal stenosis. OBJECTIVE/AIM: To compare the efficacy of UPE and BPE lumbar decompression surgery for patients with lumbar spinal stenosis. METHODS: A prospective registry of patients who had undergone spinal decompression for lumbar stenosis via UPE or BPE under a single fellowship trained spine surgeon was studied. Baseline characteristics, initial clinical presentation, and operative details including complications were recorded for all included patients. Clinical outcomes, such as visual analogue scale and Oswestry Disability Index, were recorded at preoperative, immediate postoperative, 2-week, 3-, 6-, and 12-month follow-up periods. RESULTS: A total of 62 patients underwent endoscopic decompression surgery for lumbar spinal stenosis (29 UPE, 33 BPE). No significant baseline differences were found between uniportal and biportal decompression, when comparing operative duration (130 vs. 140 min; p = 0.30), intraoperative blood loss (5.4 vs. 6mLs; p = 0.05), and length of hospital stay (23.6 vs. 20.3 h; p = 0.35). Two patients (7%) who underwent uniportal endoscopic decompression required conversion to open surgery due to inadequate decompression. Intraoperative complication rates were significantly higher in the UPE group (13.4% vs. 0%, p < 0.05). VAS score (leg & back) and ODI improved significantly (p < 0.001) in both endoscopic decompression groups across all follow-up time points, with no appreciable statistical differences between both groups. CONCLUSION: UPE has the same efficacy as BPE in the treatment of lumbar spinal stenosis. While UPE surgery enjoys added aesthetic benefits of only one wound, BPE had potentially lower risks of intraoperative complication, inadequate decompression, and conversion to open surgery during early period of learning curve.

Thermal property evaluation of a 2.5D integration method with device level microchannel direct cooling for a high-power GaN HEMT device.

Gallium nitride high electron mobility transistor (GaN HEMT) devices have become critical components in the manufacturing of high-performance radio frequency (RF) or power electronic modules due to their superior characteristics, such as high electron saturation speeds and high power densities. However, the high heat characteristics of GaN HEMTs make device level cooling a critical problem to solve since performance degradation or even failure may occur under high temperatures. In this paper, we proposed a 2.5D integration method with device-level microchannel direct cooling for a high-power GaN HEMT device. To demonstrate this technological concept, a multigate GaN HEMT device featuring a gate length/width/source drain spacing of 0.5 µm/300 µm/6 µm that underwent in-house backside thinning and metallization was used as the test vehicle. A high-resistivity silicon (HR Si) interposer embedded with four-layer microchannels was designed, having widths/pitches of 30 µm/30 µm at the top microchannel. The high-power GaN HEMT device was soldered on a Si interposer embedded with open microchannels for heat dissipation. A pair of GSG Pad chips was soldered simultaneously to display the capacity for the heterogeneous integration of other chip types. Thermal property evaluation was conducted with experiments and simulations. The test results showed that the maximum surface temperature of the GaN HEMT device decreased to 93.8 °C when it experienced a heat dissipation density of 32 kW/cm2 in the gate finger area and an average heat dissipation density of 5 kW/cm2 was found in the active area with the DI water coolant at a flow rate of 3 mL/min. To our knowledge, among recently reported works, this finding was the best cooling capacity of heterogeneously integrated microchannels for GaN HEMT devices. In addition, this technology was scalable regarding the numbers of gate fingers or GaN HEMT devices.

Deep Learning Model for Grading Metastatic Epidural Spinal Cord Compression on Staging CT.

Background: Metastatic epidural spinal cord compression (MESCC) is a disastrous complication of advanced malignancy. Deep learning (DL) models for automatic MESCC classification on staging CT were developed to aid earlier diagnosis. Methods: This retrospective study included 444 CT staging studies from 185 patients with suspected MESCC who underwent MRI spine studies within 60 days of the CT studies. The DL model training/validation dataset consisted of 316/358 (88%) and the test set of 42/358 (12%) CT studies. Training/validation and test datasets were labeled in consensus by two subspecialized radiologists (6 and 11-years-experience) using the MRI studies as the reference standard. Test sets were labeled by the developed DL models and four radiologists (2−7 years of experience) for comparison. Results: DL models showed almost-perfect interobserver agreement for classification of CT spine images into normal, low, and high-grade MESCC, with kappas ranging from 0.873−0.911 (p < 0.001). The DL models (lowest κ = 0.873, 95% CI 0.858−0.887) also showed superior interobserver agreement compared to two of the four radiologists for three-class classification, including a specialist (κ = 0.820, 95% CI 0.803−0.837) and general radiologist (κ = 0.726, 95% CI 0.706−0.747), both p < 0.001. Conclusion: DL models for the MESCC classification on a CT showed comparable to superior interobserver agreement to radiologists and could be used to aid earlier diagnosis.

Deep Learning Model for Classifying Metastatic Epidural Spinal Cord Compression on MRI.

Background: Metastatic epidural spinal cord compression (MESCC) is a devastating complication of advanced cancer. A deep learning (DL) model for automated MESCC classification on MRI could aid earlier diagnosis and referral. Purpose: To develop a DL model for automated classification of MESCC on MRI. Materials and Methods: Patients with known MESCC diagnosed on MRI between September 2007 and September 2017 were eligible. MRI studies with instrumentation, suboptimal image quality, and non-thoracic regions were excluded. Axial T2-weighted images were utilized. The internal dataset split was 82% and 18% for training/validation and test sets, respectively. External testing was also performed. Internal training/validation data were labeled using the Bilsky MESCC classification by a musculoskeletal radiologist (10-year experience) and a neuroradiologist (5-year experience). These labels were used to train a DL model utilizing a prototypical convolutional neural network. Internal and external test sets were labeled by the musculoskeletal radiologist as the reference standard. For assessment of DL model performance and interobserver variability, test sets were labeled independently by the neuroradiologist (5-year experience), a spine surgeon (5-year experience), and a radiation oncologist (11-year experience). Inter-rater agreement (Gwet's kappa) and sensitivity/specificity were calculated. Results: Overall, 215 MRI spine studies were analyzed [164 patients, mean age = 62 ± 12(SD)] with 177 (82%) for training/validation and 38 (18%) for internal testing. For internal testing, the DL model and specialists all showed almost perfect agreement (kappas = 0.92-0.98, p < 0.001) for dichotomous Bilsky classification (low versus high grade) compared to the reference standard. Similar performance was seen for external testing on a set of 32 MRI spines with the DL model and specialists all showing almost perfect agreement (kappas = 0.94-0.95, p < 0.001) compared to the reference standard. Conclusion: A DL model showed comparable agreement to a subspecialist radiologist and clinical specialists for the classification of malignant epidural spinal cord compression and could optimize earlier diagnosis and surgical referral.

The lateral entry point S2 alar-iliac (L-S2AI) screw: a preoperative computed tomography analysis of adult spinal deformity patients.

PURPOSE: To radiographically compare lateral entry point S2-alar-iliac (L-S2AI) screw with conventional S2AI (C-S2AI) and conventional iliac screw (CIS) lengths and trajectories. METHODS: Twenty-five preoperative CT scans of consecutive patients undergoing adult spinal deformity realignment surgery over a random 2-year period were analysed. Maximum in-bone length, caudal and lateral trajectories of CIS, C-S2AI, and L-S2AI screws were measured and compared using One-way ANOVA with Tukey's post hoc tests. Multivariate logistic regression was performed to identify predictors of high screw length discrepancy between C-S2AI and L-S2AI. RESULTS: Potential screw length was longest for CIS, followed by L-S2AI, then C-S2AI (114.5 ± 8.3 mm vs 101.4 ± 9.6 mm vs 80.6 ± 5.9 mm, respectively) in all patients (p < 0.001). Actual screw lengths found both CIS and L-S2AI to be longer than C-S2AI (95.3 ± 8.5 mm and 93.4 ± 7.5 mm vs 82.1 ± 7.3 mm; p = 0.008 and 0.003). Potential lateral angulation was smallest for CIS, followed by L-S2AI, then C-S2AI (21.9 ± 7.0° vs 31.9 ± 7.1° vs 40.9 ± 6.7°, respectively) in all patients (p < 0.001). L-S2AI and C-S2AI had the same caudal angulation (24.9 ± 6.8°), which was smaller than CIS (30.8 ± 5.8°) in all patients (p < 0.001). Univariate, but not multivariate analysis, revealed that lumbar lordosis > 40° (OR 7.2, p = 0.041), diagnosis of degenerative spondylolisthesis (OR 10.5, p = 0.017), and > 7 instrumented levels (OR 2.6, p = 0.049) were significantly associated with high screw discrepancies. CONCLUSION: The L-S2AI screw combines advantages of CIS and C-S2AI screws, which includes increased screw length, reduced lateral angulation, a low-profile screw head, ease of connection to proximal hardware, and the biomechanical advantage of a quadcortical purchase.

Telemedicine use in orthopaedics: Experience during the COVID-19 pandemic.

INTRODUCTION: With a recent resurgence of the 2019 coronavirus disease (COVID-19) cases globally, an increasing number of healthcare systems are adopting telemedicine as an alternative method of healthcare delivery in a bid to decrease disease transmission. Continued care of orthopaedic patients in the outpatient setting during the coronavirus disease of 2019 era can prove challenging without a systematic workflow, adequate logistics, and careful patient selection for teleconsultation. The aim of this paper is to describe our single-centre experience with the application of telemedicine in our orthopaedic practice, and its effectiveness in maintaining outpatient follow-up of orthopaedic patients. METHODOLOGY: We describe our centre's telemedicine model of care for orthopaedic patients on the outpatient follow-up - which includes workforce assembly, population health and target patients, logistics and communications, and overall workflow - with roles and responsibilities of involved people portrayed in detail. RESULTS: Feedback from both patients and orthopaedic surgeons reflected high satisfaction rates with care provided, noting minimal communication and clinical barriers compared to face-to-face consultations. Whilst not without limitations, our protocol allowed for rapid adoption of telemedicine in line with a national-wide initiative to digitize healthcare. DISCUSSION: The implementation of teleconsultation services at our orthopaedic centre has provided an effective method of healthcare delivery while enforcing social distancing measures - which proves vital in combating the spread of COVID-19 and ushering in a new normal.

Understanding "Kyphosis" and "Lordosis" for Sagittal Balancing in Two Common Standing Postures.

STUDY DESIGN: Cross-sectional radiographic comparison study. OBJECTIVE: The aim of this study was to understand whole-body balancing in directed and natural standing postures, through comparison of kypholordotic ratios on whole-body radiographs of young, healthy subjects. SUMMARY OF BACKGROUND DATA: Recent studies highlighted the importance of understanding whole-body balancing, proposing the use of the more physiological natural standing posture, together with the conventional directed standing posture, for imaging. METHODS: Sixty healthy, 21-year-old subjects (36 males, 24 females) were recruited. EOS whole-body radiographs of subjects in directed and natural standing postures were obtained. Radiographic parameters compared include C2-sagittal vertical axis (C2-SVA), C7-SVA, C2-7-SVA, global cervical angles (C0-T1 and C2-C7), regional cervical angles (C0-C2, C2-C4, C4-C7), T1-slope, global thoracic angles (T1-T12 and T1-inflection vertebra [Inf]), thoracolumbar angle (T11-L2), global lumbar angles (T12-S1 and Inf-S1), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), spinocoxa angle (SCA), and femoral alignment angle (FAA). Kypholordotic ratios of T1-12/T12-S1, T1-Inf/Inf-S1, Tl-Inf/SCA, and (T1-Inf + FAA)/(T1-slope + SCA) were calculated and compared. RESULTS: Compared to directed standing, natural standing has greater C2-SVA and C7-SVA, more lordotic global and regional cervical angles (except C0-2 angle), higher T1-slope, larger T1- T12 and T1-Inf kyphotic angles, smaller T12-S1 and Inf-S1 lordotic angles, larger PT, more lordotic SCA, and smaller SS and FAA angles. T1-12/T12-S1 and T1-Inf/Inf-S1 ratios in natural standing, and (Tl-Inf + FAA)/(T1-slope + SCA) ratio in both postures approximate 1. There were significant differences between postures for Tl-l2/Tl2-Sl, Tl-Inf/Inf-Sl and Tl-Inf/SCA ratios. CONCLUSION: Whole-body balancing requires understanding of the balance between kyphosis and lordosis, which varies with the posture of patients. Analysis of kypholordotic ratios obtained in this study allude to the importance of performing whole-body imaging in the directed standing posture, and whole-spine or whole-body imaging in the natural standing posture, so as to fully understand spinal and whole body balancing for spinal realignment surgeries.Level of Evidence: Level 3.

Anatomic techniques for cervical pedicle screw placement.

Instrumentation of the cervical spine with cervical pedicle screws (CPS) is beneficial in patients with various types of spinal pathology. Despite posing greater technical challenges, CPS instrumentation confers better fixation outcomes when compared to lateral mass screws. While developments in technology have augmented the accuracy of CPS insertion, mastery in freehand CPS insertion allows the aforementioned technologies to reach their full potential in improving patient outcomes. The aim of this article is to discuss freehand CPS insertion techniques as established in the current literature while sharing our experience in this context. A comprehensive literature search was performed using the following electronic databases: PubMed, Medline, and EMBASE. Full-text articles focusing on clinical studies with description of freehand techniques were included. Articles which were on cadaveric studies, drill jig, navigation or robotic technology were excluded. Thirteen primary references comprising 1,480 patients were included in this review. Majority of studies reported utilizing the cranial margin of lamina for C2 level as a landmark for entry point, as well as lateral to centre of the articular mass, and just medial to the lateral border of the superior articular process for C3-7 levels. Method of tracking and facilitation of trajectory was reported in multiple studies, with use of instruments ranging from curved pedicle probes to high-speed burrs. Limited studies reported specific trajectories of CPS insertion. Most studies noted testing pedicle wall integrity at various checkpoints, with pedicle screw repositioning or conversion to lateral screw mass following detection of perforation or screw malpositioning. Success in CPS insertion rests on meticulous preoperative planning to identify the ideal screw entry point and trajectory. Patient-specific drill jigs, navigation and robotic technologies, while beneficial to progress in the field of cervical spine surgery and patient outcomes, should serve primarily to augment good expertise in freehand CPS insertion technique.

Lumbar disc herniation presenting with contralateral symptoms: a case report.

Lumbar disc herniation is common and may be symptomatic. The magnetic resonance imaging (MRI) scan is an appropriate tool to confirm the diagnosis and affected level of the spine. While a disc herniation is usually associated with ipsilateral symptoms, a few cases have been reported to present with contralateral symptoms. We report a unique case of left lumbar disc herniation at L5/S1 who presented with contralateral symptoms and was successfully treated with a right L5/S1 foraminal block. However, the patient developed concordant ipsilateral symptoms 6 weeks later and was treated with left L5/S1 microdiscectomy.

Prevalence and Predictors of Pressure Injuries From Spine Surgery in the Prone Position: Do Body Morphological Changes During Deformity Correction Increase the Risks?

MINI: Pressure injuries are prevalent in patients undergoing spine surgery while prone. Multiple risk factors exist and should be addressed. We found that patients undergoing spinal deformity correction surgery are at unique risk (odds ratio 3.31, P = 0.010) due to body morphological changes occurring secondary to intraoperative changes in spinal alignment. STUDY DESIGN: Review of data and prospective study. OBJECTIVE: To investigate the prevalence and predictive factors of pressure injuries in spine surgery performed in the prone position, and to determine whether morphological changes and truncal shifts occurring during deformity correction predispose to this complication. SUMMARY OF BACKGROUND DATA: Spine surgery performed in the prone position presents the risk of developing pressure injuries. This risk is potentially increased in deformity correction, because it tends to involve more extensive procedures, with associated longer operating times. METHODS: Cases of pressure injuries after spine surgery in the prone position were reviewed to ascertain prevalence and determine risk factors. Data including patient factors (age, sex, height, weight, body mass index, American Society of Anesthesiologists grade, comorbidities, Braden scale, neurological status, spinal pathology) and surgical factors (approach, procedure type, number of screws, operated levels, operative time) were collected. Independent risk factors were identified via multivariate analysis. A subsequent prospective analysis of all patients undergoing spinal deformity correction was conducted by performing intraoperative measurements of body morphological changes and shifts in truncal positions. Statistical correlation was performed to determine whether positional shifts cause pressure injuries. RESULTS: The prevalence of pressure injuries was 23.0%. Previous skin problems (P = 0.034), myelopathy (P = 0.013), operative time >300 minutes (P = 0.005), and more than four operated levels (P = 0.006) were independent predictors of pressure injuries. Being a spinal deformity patient was also an independent risk factor for developing pressure injuries (odds ratio 3.31, P = 0.010). Significant changes in body measurements during deformity correction were predictive of pressure injuries. CONCLUSION: Pressure injuries are prevalent in patients undergoing spine surgery while prone. Future studies should investigate strategies to prevent this complication based on the multiple risk factors identified in the present study. Patients undergoing spinal deformity correction surgery are particularly at risk due to intraoperative body morphological changes. Improved padding methods should be trialed in future studies. LEVEL OF EVIDENCE: 3.