Commentary on “A Propensity Score Matched Cohort Study Comparing 3 Different Spine Pedicle Screw Fixation Methods: Freehand, Fluoroscopy-Guided, and Robot-Assisted Techniques”

Jacob Yoong-Leong Oh 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

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Accuracy of Thoracolumbar Pedicle Screw Insertion Based on Routine Use of Intraoperative Imaging and Navigation

Sundaram Pirateb Paramasivam Meenakshi,Oh Jacob Yoong-Leong,Tan Mark,Nolan Colum Patrick,Yu Chun Sing,Ling Ji Min 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.4

Study DesignRetrospective review.PurposeTo determine the accuracy of thoracolumbar pedicle screw insertion with the routine use of three-dimensional (3D) intraoperative imaging and navigation over a large series of screws in an Asian population.Overview of LiteratureThe use of 3D intraoperative imaging and navigation in spinal surgery is aimed at improving the accuracy of pedicle screw insertion. This study analyzed 2,240 pedicle screws inserted with the routine use of intraoperative navigation. It is one of very few studies done on an Asian population with a large series of screws.MethodsPatients who had undergone thoracolumbar pedicle screws insertion using intraoperative imaging and navigation between 2009 and 2017 were retrospectively analyzed. Computed tomography (CT) images acquired after the insertion of pedicle screws were analyzed for breach of the pedicle wall. The pedicle screw breaches were graded according to the Gertzbein classification. The breach rate and revision rate were subsequently calculated.ResultsA total of 2,240 thoracolumbar pedicle screws inserted under the guidance of intraoperative navigation were analyzed, and the accuracy of the insertion was 97.41%. The overall breach rate was 2.59%, the major breach rate was 0.94%, and the intraoperative screw revision rate was 0.7%. There was no incidence of return to the operating theater for revision of screws.ConclusionsThe routine use of 3D navigation and intraoperative CT imaging resulted in consistently accurate pedicle screw placement. This improved the safety of spinal instrumentation and helped in avoiding revision surgery for malpositioned screws.

Spontaneous Total Resolution of Severe Lumbar Disc Herniation

Arun-Kumar Kaliya-Perumal,Jacob Yoong-Leong Oh 전남대학교 의과학연구소 2020 전남의대학술지 Vol.56 No.1

Biportal endoscopic en bloc removal of the ligamentum flavum for spinal stenosis: nuances for the “butterfly” technique

Park Cheol Wung,Oh Jacob Yoong-Leong 대한척추외과학회 2024 Asian Spine Journal Vol.18 No.4

The introduction of endoscopic spine surgery has led to a paradigm shift in the treatment of spinal disorders. In particular, biportal endoscopic surgery has gained traction for its wider visual field and improved the maneuverability of instruments, familiar anatomy, and costeffectiveness. In this study, we describe our en bloc removal of the ligamentum flavum using a “butterfly” technique. This approach had several advantages: (1) The flavum serves as a protective barrier for the dura during drilling. (2) There is less epidural bleeding, which provides (3) better visualization. (4) In an inadvertent durotomy, this usually occurs later in the procedure, which is more manageable than the early stages of decompression. Biportal decompression for spinal stenosis can be performed using an en bloc ligamentum flavum removal technique that is safe, reproducible, and efficient. A systematic approach will help early adopters overcome the steep learning curve.

Single-Position Robotic-Assisted Prone Lateral Fusion: Technical Description and Feasibility

Yeo Quan You,Pham Martin H.,Oh Jacob Yoong-Leong 대한척추외과학회 2024 Asian Spine Journal Vol.18 No.1

Single-position lateral interbody fusion surgery has gained traction over the years because of reduced surgical time and improved operating theater workflow. With the introduction of robotics in spine surgery, surgeons can place pedicle screws with a high degree of accuracy and efficiency; moreover, the robot allows us to localize the disk space and perform endplate preparation accurately with minimal radiation. In this study, we discuss the potential synergistic benefits of integrating robotic-assisted spine surgery and singleposition prone lateral surgery. We share our technique and provide the operative nuances of using the Mazor X Stealth Edition system (Medtronic, Minneapolis, MN, USA). We highlighted the potential synergistic benefits of integrating both the prone lateral and robotic-assisted surgical techniques, including the challenges encountered. This approach is not meant to replace other techniques or be used in all patients. Instead, it adds to our arsenal for managing spine fusion.

Utilization of Spinal Navigation to Facilitate Hassle-Free Rod Placement during Minimally-Invasive Long-Construct Posterior Instrumentation

Arun-Kumar Kaliya-Perumal,Worawat Limthongkul,Jacob Yoong-Leong Oh 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.3

During minimally-invasive long-construct posterior instrumentation, it may be challenging to contour and place the rod as the screw heads are not visualized. To overcome this, we utilized the image data merging (IDM) facility of our spinal navigation system to visualize a coherent whole image of the construct throughout the procedure. Here, we describe this technique that was used for a patient in whom L1–L5 posterior instrumentation was performed. Using an IDM facility, screws are color coded and after placement, the final image is saved. Saved images of all previous screws are displayed and observed while placing the subsequent screws. Therefore, the entry point, depth, and mediolateral alignment of subsequent screws can be adjusted to fall in line with previous screws such that the rod can be placed without hassle. Moreover, final adjustments to the construct are kept to a minimum. The possibility of screw pullout due to force engaging the rod on poorly aligned screws is thus avoided.

Factors Impacting Mortality in Geriatric Patients with Acute Spine Fractures: A 12-Year Study of 613 Patients in Singapore

En Loong Soon,Adriel Zhijie Leong,Jean Chiew,Arun-Kumar Kaliya-Perumal,Chun Sing Yu,Jacob Yoong-Leong Oh 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.4

Study Design: Retrospective database analysis. Purpose: To identify risk factors that predict mortality following acute spine fractures in geriatric patients of Singapore. Overview of Literature: Acute geriatric spinal fractures contribute significantly to local healthcare costs and hospital admissions. However, geriatric mortality following acute spine fractures is scarcely assessed in the Asian population. Methods: Electronic records of 3,010 patients who presented to our hospital’s emergency department and who were subsequently admitted during 2004–2015 with alleged history of traumatic spine fractures were retrospectively reviewed, and 613 patients (mean age, 85.7±4.5 years; range, 80–101 years; men, 108; women, 505) were shortlisted. Mortality rates were reviewed up to 1 year after admission and multivariate analyses were performed to identify independent risk factors correlating with mortality. Results: Women were more susceptible to spine fractures (82.4%), with falls (77.8%) being the most common mechanism of injury. Mortality rates were 6.0%, 8.2%, and 10.4% at 3, 6, and 12 months, respectively. The most common causes of death at all 3 time points were pneumonia and ischemic heart disease. Based on the multivariate analysis at 1-year follow-up, elderly women had a lower mortality rate compared to men (p<0.001); mortality rates increased by 6.3% (p=0.024) for every 1-year increase in the patient’s age; and patients with an American Spinal Injury Association (ASIA) score of A–C had a much higher mortality rate compared to those with an ASIA score of D–E (p<0.001). Conclusions: An older age at presentation, male sex, and an ASIA score of A–C were identified as independent factors predicting increased mortality among geriatric patients who sustained acute spine fractures. The study findings highlight at-risk groups for acute spine fractures, thereby providing an opportunity to develop strategies to increase the life expectancy of these patients.

Early Postoperative Loss of Disc Height Following Transforaminal and Lateral Lumbar Interbody Fusion: A Radiographic Analysis

Kaliya-Perumal Arun-Kumar,Soh Tamara Lee Ting,Tan Mark,Oh Jacob Yoong-Leong 대한척추외과학회 2022 Asian Spine Journal Vol.16 No.4

Study Design: Retrospective comparative radiological study. Purpose: To analyze the difference in early disc height loss following transforaminal and lateral lumbar interbody fusion (TLIF and LLIF). Overview of Literature: Minimal disc height loss facilitated by the polyaxial screw heads can occur naturally due to mechanical loading following lumbar fusion procedures. This loss does not usually cause any significant foraminal narrowing. However, when there is concomitant cage subsidence, symptomatic foraminal compromise could occur, especially when posterior decompression is not performed. It is not known whether the type of procedure, TLIF or LLIF, could influence this phenomenon. Methods: Retrospectively, patients who underwent TLIF and LLIF for various degenerative conditions were shortlisted. Each of their fused levels with the cage in situ was analyzed independently, and the preoperative, postoperative, and follow-up disc height measurements were compared between the groups. In addition, the total disc height loss since surgery was calculated at final follow-up and was compared between the groups. Results: Forty-six patients (age, 64.1±8.9 years) with 70 cage levels, 35 in each group, were selected. Age, sex, construct length, preoperative disc height, cage height, and immediate postoperative disc height were similar between the groups. By 3 months, disc height of the TLIF group was significantly less and continued to decrease over time, unlike in the LLIF group. By 1 year, the TLIF group demonstrated greater disc height loss (2.30±1.3 mm) than the LLIF group (0.89±1.1 mm). However, none of the patients in either group had any symptomatic complications throughout follow-up. Conclusions: Although our study highlights the biomechanical advantage of LLIF over TLIF in maintaining disc height, none of the patients in our cohort had symptomatic complications or implant-related failures. Hence, TLIF, as it incorporates posterior decompression, remains a safe and reliable technique despite the potential for greater disc height loss.

The Optimal Screw Length of Lumbar Pedicle Screws during Minimally Invasive Surgery Fixation: A Computed Tomography-Guided Evaluation of 771 Screws

Min Jia Chua,Shiblee Siddiqui,Chun Sing Yu,Colum Patrick Nolan,Jacob Yoong-Leong Oh 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.6

Study Design: A retrospective study of radiographic parameters of patients who underwent lumbar spinal pedicle screw insertion. Purpose: The optimal length of pedicle screws is often determined by the lateral radiograph during minimally invasive surgery (MIS). Compared with open techniques, measuring the precise length of screws or assessing the cortical breach is challenging. This study aims to ascertain the optimal pedicle screw lengths on intraoperative lateral radiographs for L1–L5. Overview of Literature: Research has revealed that optimal pedicle screw length is essential to optimize fixation, especially in osteoporotic patients; however, it must be balanced against unintentional breach of the anterior cortex, risking injury to adjacent neurovascular structures as demonstrated by case reports. Methods: We reviewed intra- and postoperative computed tomography scans of 225 patients who underwent lumbar pedicle screw insertion to ascertain which of the inserted screws were ‘optimal screws.’ The corresponding lengths of these screws were analyzed on postoperative lateral radiographs to ascertain the ideal position that a screw should attain (expressed as a percentage of the entire vertebral body length). Results: We reviewed 880 screws of which 771 were optimal screws. We noted a decreasing trend in average optimal percentages of insertion into the vertebral body for pedicle screws going from L1 (average=87.60%) to L5 (average=78.87%). The subgroup analysis revealed that there was an increasing percentage of screws directed in a straight trajectory from L1 to L5, compared to a medially directed trajectory. Conclusions: During MIS pedicle screw fixation, this study recommends that pedicle screws should not exceed 85% of the vertebral body length on the lateral view for L1, 80% for L2–L4, and 75% for L5; this will minimize the risk of anterior cortical breach yet maximize pedicle screw purchase for fixation stability.

Factors Influencing Early Disc Height Loss Following Lateral Lumbar Interbody Fusion

Kaliya-Perumal Arun-Kumar,Soh Tamara Lee Ting,Tan Mark,Oh Jacob Yoong-Leong 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.5

Study Design: Retrospective radiological analysis.Purpose: To analyze the factors influencing early disc height loss following lateral lumbar interbody fusion (LLIF).Overview of Literature: Postoperative disc height loss can occur naturally as a result of mechanical loading. This phenomenon is enabled by the yielding of the polyaxial screw heads and settling of the cage to the endplates. When coupled with cage subsidence, there can be significant reduction in the foraminal space which ultimately compromises the indirect decompression achieved by LLIF.Methods: Seventy-two cage levels in 37 patients aged 62±10.2 years who underwent single or multilevel LLIF for degenerative spinal conditions were selected. Their preoperative and postoperative follow-up radiographs were used to measure the anterior disc height (ADH), posterior disc height (PDH), mean disc height (MDH), disc space angle (DSA), and segmental angle. Correlations between the loss of disc height and several factors, including age, construct length, preoperative lordosis, postoperative lordosis, disc height, cage dimensions, and cage position, were analyzed.Results: We found that the lateral interbody cages significantly increased ADH, PDH, MDH, and DSA after surgery (p <0.0001). However, there was a loss of disc height over time. All postoperative disc height parameters, especially the amount of increase in MDH (r =0.413, p <0.0001) after surgery, showed a significant positive association with early disc height loss. The levels demonstrating a significant (≥25%) height loss were those that exhibited a substantial height increase (128.3%, 4.6±3.0 to 10.5±5.6 mm) postoperatively. However, the levels that showed less than 25% height loss were those that exhibited, on average, only a 57.4% height increase post-operatively.Conclusions: The greater the postoperative increase in disc height, the greater the disc height loss throughout early follow-up. Therefore, achieving an optimal disc height rather than overcorrection is an important surgical strategy to adopt when performing LLIF.