1.Open and Minimally Invasive Transforaminal Lumbar Interbody Fusion: Comparison of Intermediate Results and Complications.
Hwee Weng Dennis HEY ; Hwan Tak HEE
Asian Spine Journal 2015;9(2):185-193
STUDY DESIGN: Prospective study. PURPOSE: To compare clinical and radiological outcomes of open vs. minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). OVERVIEW OF LITERATURE: MI-TLIF promises smaller incisions and less soft tissue dissection resulting in lower morbidity and faster recovery; however, it is technically challenging. METHODS: Twenty-five patients with MI-TLIF were compared with 25 matched open TLIF controls. A minimum 2 year follow-up and a statistical analysis of perioperative and long-term outcomes were performed. Potential complications were recorded. RESULTS: The mean ages for the open and MI-TLIF cases were 44.4 years (range, 19-69 years) and 43.6 years (range, 20-69 years), respectively. The male:female ratio was 13:12 for both groups. Average follow-up was 26.9 months for the MI-TLIF group and 29.3 months for the open group. Operative duration was significantly longer in the MI-TLIF group than that in the open group (p<0.05). No differences in estimated blood loss, duration to ambulation, or length of stay were found. Significant improvements in the Oswestry disability index and EQ-5D functional scores were observed at 6-, 12-, and 24-months in both groups, but no significant difference was detected between the groups. Fusion rates were comparable. Cage sizes were significantly smaller in the MI-TLIF group at the L5/S1 level (p<0.05). One patient had residual spinal stenosis at the MI-TLIF level, and one patient who underwent two-level MI-TLIF developed a deep vein thrombosis resulting in a pulmonary embolism. CONCLUSIONS: MI-TLIF and open TLIF had comparable long-term benefits. Due to technical constraints, patients should be advised on the longer operative time and potential undersizing of cages at the L5S1 level.
Follow-Up Studies
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Humans
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Length of Stay
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Operative Time
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Prospective Studies
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Pulmonary Embolism
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Spinal Stenosis
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Venous Thrombosis
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Walking
2.Evolving trends in surgically managed patients with proximal humerus fracture: are we different after ten years?
Choon Chiet HONG ; Dennis Hwee Weng HEY ; Diarmuid MURPHY
Singapore medical journal 2014;55(11):574-578
INTRODUCTIONNew knowledge, and improved surgical hardware and fixation techniques have changed surgical management. We review the evolving trends of surgically managed proximal humerus fractures.
METHODSPatients who underwent surgery for proximal humerus fractures from 1 January 2001 to 31 December 2010 were identified from the hospital's electronic diagnosis and operative coding database. Data extracted from the database included patient demographics, comorbidities, clinical and radiological findings, operative techniques, and complications.
RESULTSIn total, 95 patients with 97 surgically managed proximal humerus fractures were identified. The median age of the patients was 50 (range 12-85) years, and the male to female ratio was 1.2:1.0. Male patients tended to present at a younger age than female patients (peak age 30-39 years vs. 70-79 years, p < 0.001). Two-part surgical neck fracture was the most common type of fracture (n = 33, 34.0%). Plate osteosynthesis was predominantly used for two- and three-part surgical neck fractures involving the greater tuberosity (p = 0.03, p = 0.0002, respectively). Hemiarthroplasty was commonly performed for four-part fractures (p < 0.001). Wound infections, implant failure, avascular necrosis of the humeral head and nonunion were seen in 8 (8.3%) cases. Minimally invasive plate osteosynthesis (MIPO) had been in use since 2007 (p < 0.001).
CONCLUSIONSurgically managed proximal humerus fractures predominantly involved young men following high velocity injury and elderly women following osteoporotic fractures. Open plating was most commonly used for two- and three-part fractures, and hemiarthroplasty for four-part fractures. MIPO techniques have been practised in our institution since 2007.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Female ; Fracture Fixation, Internal ; trends ; Hemiarthroplasty ; trends ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Shoulder Fractures ; surgery ; Young Adult
4.A Comparison between Structural Allografts and Polyetheretherketone Interbody Spacers Used in Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-analysis
Francis Jia Yi FONG ; Chee Yit LIM ; Jun-Hao TAN ; Hwee Weng Dennis HEY
Asian Spine Journal 2024;18(1):124-136
Among interbody implants used during anterior cervical discectomy and fusion (ACDF), structural allografts and polyetheretherketone (PEEK) are the most used spacers. Currently, no consensus has been established regarding the superiority of either implant, with US surgeons preferring structural allografts, whereas UK surgeons preferring PEEK. The purpose of this systematic review (level of evidence, 4) was to compare postoperative and patient-reported outcomes between the use of structural allografts PEEK interbody spacers during ACDF. Five electronic databases (PubMed, Embase, Scopus, Web of Science, and Cochrane) were searched for articles comparing the usage of structural allograft and PEEK interbody spacers during ACDF procedures from inception to April 10, 2023. The searches were conducted using the keywords “Spine,” “Allograft,” and “PEEK” and were performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. Subsequent quality and sensitivity analyses were performed on the included studies. Nine studies involving 1,074 patients were included. Compared with the PEEK group, the structural allograft group had comparable rates of postoperative pseudoarthrosis (p=0.58). However, when stratified according to the number of levels treated, the 3-level ACDF PEEK group was 3.45 times more likely to have postoperative pseudoarthrosis than the structural allograft group (p=0.01). Subsequent postoperative outcomes (rate of subsidence and change in the preoperative and postoperative segmental disc heights) were comparable between the PEEK and structural allograft groups. Patient-reported outcomes (Visual Analog Scale [VAS] of neck pain and Neck Disability Index [NDI]) were comparable. This study showed that for 3-level ACDFs, the use of structural allografts may confer higher fusion rates. However, VAS neck pain, NDI, and subsidence rates were comparable between structural allografts and PEEK cages. In addition, no significant difference in pseudoarthrosis rates was found between PEEK cages and structural allografts in patients undergoing 1- and 2-level ACDFs.
5.Symptomatic Construct Failure after Metastatic Spine Tumor Surgery
Naresh KUMAR ; Ravish PATEL ; Jiong Hao TAN ; Joshua SONG ; Naveen PANDITA ; Dennis Hwee Weng HEY ; Leok Lim LAU ; Gabriel LIU ; Joseph THAMBIAH ; Hee-Kit WONG
Asian Spine Journal 2021;15(4):481-490
Methods:
We conducted a retrospective analysis on 288 patients (246 for final analysis) who underwent MSTS between 2005–2015. Data collected were demographics and peri/postoperative clinical and radiological features. Early and late radiological SF were defined as presentation before and after 3 months from index surgery, respectively. Univariate and multivariate models of competing risk regression analysis were designed to determine the risk factors for SF with death as a competing event.
Results:
We observed 14 SFs (5.7%) in 246 patients; 10 (4.1%) underwent revision surgery. Median survival was 13.4 months. The mean age was 58.8 years (range, 21–87 years); 48.4% were women. The median time to failure was 5 months (range, 1–60 months). Patients with SF were categorized into three groups: (1) SF when the primary implant was revised (n=5, 35.7%); (2) peri-construct progression of disease requiring extension (n=5, 35.7%); and (3) SFs that did not warrant revision (n=4, 28.5%). Four patients (28.5%) presented with early failure. SF commonly occurred at the implant-bone interface (9/14) and all patients had a spinal instability neoplastic score (SINS) >7. Thirteen patients (92.8%) who developed failure had fixation spanning junctional regions. Multivariate competing risk regression showed that preoperative Eastern Cooperative Oncology Group score was a significant risk factor for implant failure (adjusted sub-hazard ratio, 7.0; 95% confidence interval, 1.63–30.07; p<0.0009).
Conclusions
The incidence of SF (5.7%) was low in patients undergoing MSTS although these patients did not undergo spinal fusion. Preoperative ambulators involved a 7 times higher risk of failure than non-ambulators. Preoperative SINS >7 and fixations spanning junctional regions were associated with SF. Majority of construct failures occurred at the implant-bone interface.
6.Asymptomatic Construct Failure after Metastatic Spine Tumor Surgery: A New Entity or a Continuum with Symptomatic Failure?
Naresh KUMAR ; Ravish PATEL ; Barry Wei Loong TAN ; Jiong Hao TAN ; Naveen PANDITA ; Dhiraj SONAWANE ; Keith Gerard LOPEZ ; Khin Lay WAI ; Hwee Weng Dennis HEY ; Aravind KUMAR ; Gabriel LIU
Asian Spine Journal 2021;15(5):636-649
Methods:
We conducted a retrospective analysis of 288 patients (246 for final analysis) who underwent MSTS between 2005–2015. Data collected were demographics and peri/postoperative clinical and radiological features. Early and late radiological AsCF were defined as presentation before and after 3 months, respectively. We analyzed patients with AsCF for risk factors and survival duration by performing competing risk regression analyses where AsCF was the event of interest, with SF and death as competing events.
Results:
We observed AsCF in 41/246 patients (16.7%). The mean time to onset of AsCF after MSTS was 2 months (range, 1–9 months). Median survival of patients with AsCF was 20 and 41 months for early and late failures, respectively. Early AsCF accounted for 80.5% of cases, while late AsCF accounted for 19.5%. The commonest radiologically detectable AsCF mechanism was angular deformity (increase in kyphus) in 29 patients. Increasing age (p<0.02) and primary breast (13/41, 31.7%) (p<0.01) tumors were associated with higher AsCF rates. There was a non-significant trend towards AsCF in patients with a spinal instability neoplastic score ≥7, instrumentation across junctional regions, and construct lengths of 6–9 levels. None of the patients with AsCF underwent revision surgery.
Conclusions
AsCF after MSTS is a distinct entity. Most patients with early AsCF did not require intervention. Patients who survived and maintained ambulation for longer periods had late failure. Increasing age and tumors with a better prognosis have a higher likelihood of developing AsCF. AsCF is not necessarily an indication for aggressive/urgent intervention.
7.Sagittal Radiographic Parameters of the Spine in Three Physiological Postures Characterized Using a Slot Scanner and Their Potential Implications on Spinal Weight-Bearing Properties
Hwee Weng Dennis HEY ; Nathaniel Li-Wen NG ; Khin Yee Sammy LOH ; Yong Hong TAN ; Kimberly-Anne TAN ; Vikaesh MOORTHY ; Eugene Tze Chun LAU ; Gabriel LIU ; Hee-Kit WONG
Asian Spine Journal 2021;15(1):23-31
Methods:
We recruited young patients with nonspecific low back pain for <3 months, who were otherwise healthy. Each patient had EOS images taken in the flexed, erect and extended positions, in random order, as well as magnetic resonance imaging to assess for disk degeneration. Angular and disk height measurements were performed and compared in all three postures using paired t-tests. Changes in disk height relative to the erect posture were caclulated to determine the alignment-specific load-bearing area of each FSU.
Results:
Eighty-three patients (415 lumbar intervertebral disks) were studied. Significant alignment changes were found between all three postures at L1/2, and only between erect and flexion at the other FSUs. Disk height measurements showed that the neutral axis of the spine, marked by zones where disk heights did not change, varied between postures and was level specific. The load-bearing areas were also found to be more anterior in flexion and more posterior in extension, with the erect spine resembling the extended spine to a greater extent.
Conclusions
Load-bearing areas of the lumbar spine are sagittal alignment-specific and level-specific. This may imply that, depending on the surgical realignment strategy, attention should be paid not just to placing an intervertebral cage “as anterior as possible” for generating lordosis, but also on optimizing load-bearing in the lumbar spine.
8.Symptomatic Construct Failure after Metastatic Spine Tumor Surgery
Naresh KUMAR ; Ravish PATEL ; Jiong Hao TAN ; Joshua SONG ; Naveen PANDITA ; Dennis Hwee Weng HEY ; Leok Lim LAU ; Gabriel LIU ; Joseph THAMBIAH ; Hee-Kit WONG
Asian Spine Journal 2021;15(4):481-490
Methods:
We conducted a retrospective analysis on 288 patients (246 for final analysis) who underwent MSTS between 2005–2015. Data collected were demographics and peri/postoperative clinical and radiological features. Early and late radiological SF were defined as presentation before and after 3 months from index surgery, respectively. Univariate and multivariate models of competing risk regression analysis were designed to determine the risk factors for SF with death as a competing event.
Results:
We observed 14 SFs (5.7%) in 246 patients; 10 (4.1%) underwent revision surgery. Median survival was 13.4 months. The mean age was 58.8 years (range, 21–87 years); 48.4% were women. The median time to failure was 5 months (range, 1–60 months). Patients with SF were categorized into three groups: (1) SF when the primary implant was revised (n=5, 35.7%); (2) peri-construct progression of disease requiring extension (n=5, 35.7%); and (3) SFs that did not warrant revision (n=4, 28.5%). Four patients (28.5%) presented with early failure. SF commonly occurred at the implant-bone interface (9/14) and all patients had a spinal instability neoplastic score (SINS) >7. Thirteen patients (92.8%) who developed failure had fixation spanning junctional regions. Multivariate competing risk regression showed that preoperative Eastern Cooperative Oncology Group score was a significant risk factor for implant failure (adjusted sub-hazard ratio, 7.0; 95% confidence interval, 1.63–30.07; p<0.0009).
Conclusions
The incidence of SF (5.7%) was low in patients undergoing MSTS although these patients did not undergo spinal fusion. Preoperative ambulators involved a 7 times higher risk of failure than non-ambulators. Preoperative SINS >7 and fixations spanning junctional regions were associated with SF. Majority of construct failures occurred at the implant-bone interface.
9.Thoracolumbar Injury Classification and Severity Score Is Predictive of Perioperative Adverse Events in Operatively Treated Thoracic and Lumbar Fractures
Gabriel LIU ; Jiong Hao TAN ; Jun Cheong KONG ; Yong Hao Joel TAN ; Nishant KUMAR ; Shen LIANG ; Seah Jing Sheng SHAWN ; Chiu Shi TING ; Lau Leok LIM ; Hey Hwee Weng DENNIS ; Naresh KUMAR ; Joseph THAMBIAH ; Hee-Kit WONG
Asian Spine Journal 2022;16(6):848-856
Methods:
We performed a retrospective review of 199 patients with surgically treated thoracolumbar fractures operated between January 2007 and January 2018. The potential risk factors for the development of AEs as well as the development of common complications were evaluated by univariate analysis, and a multivariate logistic regression analysis was performed to identify independent risk factors predictive of the above.
Results:
The overall rate of AEs was 46.7%; 83 patients (41.7%) had nonsurgical AEs, whereas 24 (12.1%) had surgical adverse events. The most common AEs were urinary tract infections in 43 patients (21.6%), and hospital-acquired pneumonia in 21 patients (10.6%). On multivariate logistic regression, a Thoracolumbar Injury Classification and Severity (TLICS) score of 8–10 (odds ratio [OR], 6.39; 95% confidence interval [CI], 2.33–17.51), the presence of polytrauma (OR, 2.64; 95% CI, 1.17–5.99), and undergoing open surgery (OR, 2.31; 95% CI, 1.09–4.88) were significant risk factors for AEs. The absence of neurological deficit was associated with a lower rate of AEs (OR, 0.47; 95% CI, 0.31–0.70).
Conclusions
This study suggests the presence of polytrauma, preoperative American Spinal Injury Association score, and TLICS score are predictive of AEs in patients with surgically treated thoracolumbar fractures. The results might also suggest a role for minimally invasive surgical methods in reducing AEs in these patients.