Dino Samartzis - Academia.edu (original) (raw)

Papers by Dino Samartzis

Spine, 2005

A prospective, cohort study of 11 patients who underwent either a posterior lumbar spinal fusion ... more A prospective, cohort study of 11 patients who underwent either a posterior lumbar spinal fusion with instrumentation (n = 7) or a lumbar laminotomy and discectomy alone (n = 4) and who were evaluated by dual energy radiograph absorptiometry (DEXA) to determine bone mineral density (BMD) at the adjacent three cephalad vertebral levels. To determine long-term BMD changes that occur at the adjacent three levels above an instrumented posterolateral lumbar fusion or an isolated laminotomy and lumbar discectomy. No long-term prospective study has evaluated the affects of instrumented lumbar fusions on bone remodeling at adjacent vertebral levels. Several studies in animals and humans have reported a decrease in BMD at the adjacent level during the first 6 months after spinal fusion with a return to baseline at 1-year follow-up in up to 60% of patients. DEXA was performed initially at a mean postoperative follow-up of 4 years (range, 2.3-5.5 years) and again at a mean of 10.8 years (range, 9.1-2.4 years). Eleven patients were divided into two groups: laminotomy and discectomy (n = 4) and instrumented posterior spinal fusion (n = 7). All patients underwent surgical procedures at the L4-L5 or L5-S1 levels with DEXA analysis being performed on the adjacent three cephalad levels. The discectomy group (mean age, 57.8 years) underwent lumbar hemilaminotomy without fusion whereas the other group (mean age, 60 years) underwent pedicle-screw instrumentation and posterolateral lumbar fusion. Peripheral sites, including the femoral neck, were included in the DEXA analysis to normalize for individual differences in bone mineral metabolism. At the mean 10.8-year follow-up, the fusion group was noted to have at the adjacent level, two levels cephalad, and three levels cephalad normalized BMDs of 1.47, 1.39, and 1.27, respectively. A 14.8%, 10.8%, and 9.5% increase respectively in normalized BMD was observed when compared with the mean 4-year fusion values (P < 0.05). This increase was also noted on comparative T-score, Z-score, and absolute BMD values (P < 0.05). The discectomy group when evaluated revealed no statistically significant change from the mean 4 to 10.8-year follow-up (BMD, normalized BMD, T-score, Z-score). No statistically significant difference was noted in hip BMD at the mean 4-year and 10.8-year follow-up (1.05 versus 1.03), suggesting that the effects were local. The local BMD adjacent to an instrumented lumbar fusion is increased at a mean of 10.8-years after surgery. There is a gradual decrease in BMD changes with increasing distance from the fusion level. Alterations in fusion site biomechanics and modulus mismatch between the host bone and the spinal instrumentation most likely result in chronic, localized bone remodeling with an increased BMD that decreases the greater the distance from the fusion mass.

Encyclopedia of Global Health, 2008

Encyclopedia of Global Health, 2008

Encyclopedia of Global Health, 2008

Journal of Neurosurgery: Spine, 2008

International journal of clinical and experimental pathology, 2015

Apoptosis plays an important role in intervertebral disc degeneration (IDD). Overwhelming evidenc... more Apoptosis plays an important role in intervertebral disc degeneration (IDD). Overwhelming evidence indicates that RASSF7 is essential for cell growth and apoptosis. Recently, it has been noted that the JNK signaling can be negatively regulated by suppressing phosphorylated-MKK7 activation during pro-apoptosis. We aimed to investigate the RASSF7 expression level in human degenerative nucleus pulposus (NP) cells and non-degenerative NP cells and the link between RASSF7-JNK with NP cells apoptosis. We harvested NP tissues from 20 IDD patients as disease group and 8 cadaveric donors as normal controls. We detected RASSF7 expression by Real-time-PCR and western blotting. Consequently, we found that the expression of RASSF7 was higher in non-degenerative group than in degenerative group (P<0.05). Overexpression of RASSF7 in degenerative NP cells led to decreased apoptosis rate than that in scramble group (P<0.05). Collectively, our findings suggest that RASSF7 plays an important rol...

European Spine Journal, 2016

Low back pain (LBP) is the most disabling condition worldwide. Although LBP relates to different ... more Low back pain (LBP) is the most disabling condition worldwide. Although LBP relates to different spinal pathologies, vertebral bone marrow lesions visualized as Modic changes on MRI have a high specificity for discogenic LBP. This review summarizes the pathobiology of Modic changes and suggests a disease model. Non-systematic literature review. Chemical and mechanical stimulation of nociceptors adjacent to damaged endplates are likely a source of pain. Modic changes are adjacent to a degenerated intervertebral disc and have three generally interconvertible types suggesting that the different Modic change types represent different stages of the same pathological process, which is characterized by inflammation, high bone turnover, and fibrosis. A disease model is suggested where disc/endplate damage and the persistence of an inflammatory stimulus (i.e., occult discitis or autoimmune response against disc material) create predisposing conditions. The risk to develop Modic changes likely depends on the inflammatory potential of the disc and the capacity of the bone marrow to respond to it. Bone marrow lesions in osteoarthritic knee joints share many characteristics with Modic changes adjacent to degenerated discs and suggest that damage-associated molecular patterns and marrow fat metabolism are important pathogenetic factors. There is no consensus on the ideal therapy. Non-surgical treatment approaches including intradiscal steroid injections, anti-TNF-α antibody, antibiotics, and bisphosphonates have some demonstrated efficacy in mostly non-replicated clinical studies in reducing Modic changes in the short term, but with unknown long-term benefits. New diagnostic tools and animal models are required to improve painful Modic change identification and classification, and to clarify the pathogenesis. Modic changes are likely to be more than just a coincidental imaging finding in LBP patients and rather represent an underlying pathology that should be a target for therapy.

The American Journal of Orthopedics, Mar 1, 2008

Orthopedics, Mar 1, 2006

The HKU Scholars Hub is the institutional repository of The University of Hong Kong. It seeks to ... more The HKU Scholars Hub is the institutional repository of The University of Hong Kong. It seeks to collect the intellectual output of HKU and make it available to the widest possible audience. Records are made in the Hub for items that are fulltext open access, or for URLs that hyperlink ...

Spine, Feb 1, 2010

Prospective, controlled, observational outcome study using clinical, radiographic, and patient/ph... more Prospective, controlled, observational outcome study using clinical, radiographic, and patient/physician-based questionnaire data, with patient outcomes at 12 months follow-up. To validate appropriateness criteria for low back surgery. Most surgical treatment failures are attributed to poor patient selection, but no widely accepted consensus exists on detailed indications for appropriate surgery. Appropriateness criteria for low back surgery have been developed by a multispecialty panel using the RAND appropriateness method. Based on panel criteria, a prospective study compared outcomes of patients appropriately and inappropriately treated at a single institution with 12 months follow-up assessment. Included were patients with low back pain and/or sciatica referred to the neurosurgical department. Information about symptoms, neurologic signs, the health-related quality of life (SF-36), disability status (Roland-Morris), and pain intensity (VAS) was assessed at baseline, at 6 months, and at 12 months follow-up. The appropriateness criteria were administered prospectively to each clinical situation and outside of the clinical setting, with the surgeon and patients blinded to the results of the panel decision. The patients were further stratified into 2 groups: appropriate treatment group (ATG) and inappropriate treatment group (ITG). Overall, 398 patients completed all forms at 12 months. Treatment was considered appropriate for 365 participants and inappropriate for 33 participants. The mean improvement in the SF-36 physical component score at 12 months was significantly higher in the ATG (mean: 12.3 points) than in the ITG (mean: 6.8 points) (P = 0.01), as well as the mean improvement in the SF-36 mental component score (ATG mean: 5.0 points; ITG mean: -0.5 points) (P = 0.02). Improvement was also significantly higher in the ATG for the mean VAS back pain (ATG mean: 2.3 points; ITG mean: 0.8 points; P = 0.02) and Roland-Morris disability score (ATG mean: 7.7 points; ITG mean: 4.2 points; P = 0.004). The ATG also had a higher improvement in mean VAS for sciatica (4.0 points) than the ITG (2.8 points), but the difference was not significant (P = 0.08). The SF-36 General Health score declined in both groups after 12 months, however, the decline was worse in the ITG (mean decline: 8.2 points) than in the ATG (mean decline: 1.2 points) (P = 0.04). Overall, in comparison to ITG patients, ATG patients had significantly higher improvement at 12 months, both statistically and clinically. In comparison to previously reported literature, our study is the first to assess the utility of appropriateness criteria for low back surgery at 1-year follow-up with multiple outcome dimensions. Our results confirm the hypothesis that application of appropriateness criteria can significantly improve patient outcomes.

The Journal of Bone and Joint Surgery American Volume, 2010

The fulcrum bending radiograph accurately predicts scoliosis curve correction in patients with th... more The fulcrum bending radiograph accurately predicts scoliosis curve correction in patients with thoracic adolescent idiopathic scoliosis who are managed with hooks. We assessed the predictive value of the fulcrum bending radiograph in the context of alternate-level pedicle screw fixation of the scoliotic spine. A prospective radiographic analysis of patients with thoracic adolescent idiopathic scoliosis who were managed operatively with alternate-level pedicle screw fixation at a single institution was performed. The Cobb angle was measured on posteroanterior standing coronal radiographs that were made preoperatively and one week postoperatively. The fulcrum flexibility percentage and the fulcrum bending correction index percentage were calculated. Forty-two patients were assessed. The mean age at the time of surgery was 14.6 years, and the mean number of fused levels was 9.4. On the preoperative radiographs, the mean values for the standing Cobb angle, the fulcrum bending radiograph Cobb angle, and fulcrum flexibility were 57.9 degrees, 21.8 degrees, and 62.7%, respectively. On the one-week postoperative radiographs, the mean Cobb angle was 15.4 degrees, the mean curve correction was 73.4%, and the mean fulcrum bending correction index was 122.1%. A significant, positive correlation was noted between the fulcrum bending radiograph angle and the fulcrum bending correction index, indicating that the fulcrum bending radiograph could predict the correction of flexible curves; however, for stiff curves, pedicle screws could provide more correction than the fulcrum bending radiograph predicted. To our knowledge, this is the first study to demonstrate the predictive value of the fulcrum bending radiograph in the context of alternate-level pedicle screw fixation in patients with adolescent idiopathic scoliosis. Curve flexibility may dictate the degree of the fulcrum bending correction index, whereby a curve that is less flexible may achieve a greater fulcrum bending correction index. The fulcrum bending radiograph has potential predictive utility. In addition, pedicle screw constructs appear to have a better ability to correct scoliosis in comparison with hooks and hybrid constructs.

The Spine Journal, 2010

« PreviousNext »The Spine Journal Volume 10, Issue 3 , Pages 277-278, March 2010. Spinal flexibil... more « PreviousNext »The Spine Journal Volume 10, Issue 3 , Pages 277-278, March 2010. Spinal flexibility in scoliosis: roots “bending” to antiquity. Dino Samartzis, DSc, PhD, MSc: Affiliations.Hong Kong, SAR China. email address ,; Frank La Marca, MD: Affiliations. MI, USA. ...

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > October ...

Spine J, 2008

... Powered by DSpace, version 1.6.2. Engineered by CILEA. This site implements DCMI Metadata thr... more ... Powered by DSpace, version 1.6.2. Engineered by CILEA. This site implements DCMI Metadata through meta-tags and an OAI-compliant repository located here. The University of Hong Kong Libraries, University of Hong Kong | Contact Us.

Annual Meeting of the International Society For the Study of the Lumbar Spine, Apr 11, 2014

ABSTRACT Study Design: Case-control studyObjective: The aim of this study was to define clinicall... more ABSTRACT Study Design: Case-control studyObjective: The aim of this study was to define clinically-relevant relative and critical (absolute) MRI values of lumbar spinal stenosis in a cohort of 100 surgical cases and 100 asymptomatic controls.Summary of Background Data: Developmental spinal stenosis is a precipitating factor in patients presenting with lumbar canal stenosis. Yet due to a lack of agreement on definitions and methods of assessment, as well as ethnic-specific normative values, its prevalence and significance is not known.Methods: This was a case-control study comparing 100 age and sex-matched asymptomatic, volunteers to that of 100 patients who underwent surgery for spinal stenosis. All patients were of Chinese ethnicity and their details were blinded to two observers. Spinal stenosis parameters were measured based on axial (pedicle level) and sagittal (mid-sagittal) MRI scans.Results: Anteroposterior (AP) spinal canal diameters changes with levels. At each level, patients were found to have significantly narrower AP canal diameters compared with controls. By use of receiver operating characteristic (ROC) curve, we defined developmental spinal stenosis if the AP canal diameter at L1&lt;20mm, L2&lt;19mm, L3&lt;19mm, L4&lt;17mm, L5&lt;16mm and at S1&lt;16mm based on a value including 50% of controls and demonstrated best sensitivity and specificity. Furthermore, for L4, L5 and S1, critical stenosis values could be defined, below which almost all subjects needed surgery, these were L4&lt;14mm, L5&lt;14mm and S1&lt;12mm.Conclusion: This is the largest MRI-based study with standardized measurements and comparable groups to determine clinically-relevant MRI criteria for lumbar spinal stenosis. The findings strongly suggest that developmental stenosis plays an important role in the pathogenesis of symptomatic spinal stenosis. Critical values of stenosis below which symptoms were highly likely were defined. These will need to be validated by longitudinal studies in future. However, they may possess clinical utility in determining the appropriate levels requiring canal-widening surgery.

A cross-sectional, population-based cohort study. The objective of this study was to evaluate the... more A cross-sectional, population-based cohort study. The objective of this study was to evaluate the clinical relevance of skipped level disc degeneration (SLDD) to that of contiguous, multilevel disc degeneration (CMDD) of the lumbar spine. The study also aimed to identify patterns of SLDD, its classification, prevalence, and clinical relevance. The association of disc degeneration on magnetic resonance imaging with low back pain (LBP) remains questionable. The occurrence of SLDD of the lumbar spine has recently been noted. To date, patterns of disc degeneration have been overlooked in the association with low back symptoms. A population-based radiographic and clinical study of 3099 Southern Chinese patients. Individuals with multilevel disc degeneration of the lumbar spine on sagittal T2-weighted magnetic resonance imaging (N = 1457) were stratified to SLDD (n = 301; 20.7%) or CMDD (n = 1156; 79.3%) groups. SLDD was further classified into 5 types by the relative location of nondegenerated normal disc(s) to degenerated disc levels. Subject demographics, presence of LBP, pain intensity, and functional disability were assessed. In the multivariate analyses, CMDD increased the likelihood of historical LBP (odds ratio [OR]: 1.39; 95% confidence interval [CI]: 1.00-1.93; P = 0.047) and pain severity (OR: 1.83; 95% CI: 1.23-2.73; P = 0.003) in comparison with SLDD. A significant increasing trend of number of levels with disc degeneration, overall disc degeneration severity, and presence of disc bulges/extrusions was noted from SLDD type I (least severe) to SLDD type V (most severe) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). A higher prevalence of LBP and a higher pain intensity were observed in SLDD classification type V. Functional disability scores did not differ between CMDD and SLDD, nor within SLDD classification types (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Our large-scale study is the first to describe novel variants of SLDD types and their clinical relevance. More important, LBP and severity of pain were more pronounced in individuals with CMDD rather than those with SLDD. Our study suggests that subjects with a similar degree but different patterns of multilevel disc degeneration do differ with respect to low back symptoms. This finding may provide new evidence with regard to the mechanism of LBP.

The Spine Journal, 2015

Growing rods are commonly used for surgical treatment of skeletally immature patients with scolio... more Growing rods are commonly used for surgical treatment of skeletally immature patients with scoliosis, but require repeated surgeries for distractions and are fraught with complications. As an alternative, the use of magnetically-controlled growing rods (MCGR) allow for more frequent non-invasive distractions to mimic normal growth. However, more plain radiographs are needed to monitor increased distraction frequency, thereby increasing ionizing radiation exposure to the developing child. The use of ultrasound, which emits no radiation, has been found in a cross-sectional study to be reliable in measuring MCGR distractions. To address the prospective clinical utility of ultrasound compared to plain radiographs for assessing MCGR distractions. Prospective study. Early onset scoliosis patients undergoing distractions after MCGR implantation. Measured distraction length on plain radiographs and ultrasound. This is a prospective study of patients treated with MCGR. Patients with both single and dual rod systems were included. Out-patient distractions were performed at monthly intervals, targeting 2mm of distraction on each occasion. Assessment of distraction length was monitored by ultrasound at each visit, plain radiographs were taken every six months and compared with ultrasound measurements. Nine patients (5 females, 4 males) with a mean of 29 distractions (SD ±14.3) were recruited. The mean distracted length per 6-months was 5.7mm (SD ±3.6mm) on plain radiographs and 5.2mm (SD ±3.9mm) on ultrasound for the concave rod; and 6.1mm (SD ±3.6mm) on plain radiographs and 5.9mm (SD ±3.8mm) on ultrasound for the convex rod. Excellent inter- and intra-rator reliability was observed for radiographic and ultrasound measurements. Excellent correlation was noted between the two imaging modalities (r=0.93; p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). This is the first prospective study to validate that ultrasound assessment of MCGR distraction lengths was highly comparable to that of plain radiographs. This study has verified that the ultrasound can be used to document length changes by distraaction over time and had high clinical utility. Ultrasound can be a reliable alternative to plain radiographs; thereby, avoiding radiation exposure and its potential detrimental sequelae in the developing child.

Spine, 2005

A prospective, cohort study of 11 patients who underwent either a posterior lumbar spinal fusion ... more A prospective, cohort study of 11 patients who underwent either a posterior lumbar spinal fusion with instrumentation (n = 7) or a lumbar laminotomy and discectomy alone (n = 4) and who were evaluated by dual energy radiograph absorptiometry (DEXA) to determine bone mineral density (BMD) at the adjacent three cephalad vertebral levels. To determine long-term BMD changes that occur at the adjacent three levels above an instrumented posterolateral lumbar fusion or an isolated laminotomy and lumbar discectomy. No long-term prospective study has evaluated the affects of instrumented lumbar fusions on bone remodeling at adjacent vertebral levels. Several studies in animals and humans have reported a decrease in BMD at the adjacent level during the first 6 months after spinal fusion with a return to baseline at 1-year follow-up in up to 60% of patients. DEXA was performed initially at a mean postoperative follow-up of 4 years (range, 2.3-5.5 years) and again at a mean of 10.8 years (range, 9.1-2.4 years). Eleven patients were divided into two groups: laminotomy and discectomy (n = 4) and instrumented posterior spinal fusion (n = 7). All patients underwent surgical procedures at the L4-L5 or L5-S1 levels with DEXA analysis being performed on the adjacent three cephalad levels. The discectomy group (mean age, 57.8 years) underwent lumbar hemilaminotomy without fusion whereas the other group (mean age, 60 years) underwent pedicle-screw instrumentation and posterolateral lumbar fusion. Peripheral sites, including the femoral neck, were included in the DEXA analysis to normalize for individual differences in bone mineral metabolism. At the mean 10.8-year follow-up, the fusion group was noted to have at the adjacent level, two levels cephalad, and three levels cephalad normalized BMDs of 1.47, 1.39, and 1.27, respectively. A 14.8%, 10.8%, and 9.5% increase respectively in normalized BMD was observed when compared with the mean 4-year fusion values (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). This increase was also noted on comparative T-score, Z-score, and absolute BMD values (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The discectomy group when evaluated revealed no statistically significant change from the mean 4 to 10.8-year follow-up (BMD, normalized BMD, T-score, Z-score). No statistically significant difference was noted in hip BMD at the mean 4-year and 10.8-year follow-up (1.05 versus 1.03), suggesting that the effects were local. The local BMD adjacent to an instrumented lumbar fusion is increased at a mean of 10.8-years after surgery. There is a gradual decrease in BMD changes with increasing distance from the fusion level. Alterations in fusion site biomechanics and modulus mismatch between the host bone and the spinal instrumentation most likely result in chronic, localized bone remodeling with an increased BMD that decreases the greater the distance from the fusion mass.

Encyclopedia of Global Health, 2008

Encyclopedia of Global Health, 2008

Encyclopedia of Global Health, 2008

Journal of Neurosurgery: Spine, 2008

International journal of clinical and experimental pathology, 2015

Apoptosis plays an important role in intervertebral disc degeneration (IDD). Overwhelming evidenc... more Apoptosis plays an important role in intervertebral disc degeneration (IDD). Overwhelming evidence indicates that RASSF7 is essential for cell growth and apoptosis. Recently, it has been noted that the JNK signaling can be negatively regulated by suppressing phosphorylated-MKK7 activation during pro-apoptosis. We aimed to investigate the RASSF7 expression level in human degenerative nucleus pulposus (NP) cells and non-degenerative NP cells and the link between RASSF7-JNK with NP cells apoptosis. We harvested NP tissues from 20 IDD patients as disease group and 8 cadaveric donors as normal controls. We detected RASSF7 expression by Real-time-PCR and western blotting. Consequently, we found that the expression of RASSF7 was higher in non-degenerative group than in degenerative group (P<0.05). Overexpression of RASSF7 in degenerative NP cells led to decreased apoptosis rate than that in scramble group (P<0.05). Collectively, our findings suggest that RASSF7 plays an important rol...

European Spine Journal, 2016

Low back pain (LBP) is the most disabling condition worldwide. Although LBP relates to different ... more Low back pain (LBP) is the most disabling condition worldwide. Although LBP relates to different spinal pathologies, vertebral bone marrow lesions visualized as Modic changes on MRI have a high specificity for discogenic LBP. This review summarizes the pathobiology of Modic changes and suggests a disease model. Non-systematic literature review. Chemical and mechanical stimulation of nociceptors adjacent to damaged endplates are likely a source of pain. Modic changes are adjacent to a degenerated intervertebral disc and have three generally interconvertible types suggesting that the different Modic change types represent different stages of the same pathological process, which is characterized by inflammation, high bone turnover, and fibrosis. A disease model is suggested where disc/endplate damage and the persistence of an inflammatory stimulus (i.e., occult discitis or autoimmune response against disc material) create predisposing conditions. The risk to develop Modic changes likely depends on the inflammatory potential of the disc and the capacity of the bone marrow to respond to it. Bone marrow lesions in osteoarthritic knee joints share many characteristics with Modic changes adjacent to degenerated discs and suggest that damage-associated molecular patterns and marrow fat metabolism are important pathogenetic factors. There is no consensus on the ideal therapy. Non-surgical treatment approaches including intradiscal steroid injections, anti-TNF-α antibody, antibiotics, and bisphosphonates have some demonstrated efficacy in mostly non-replicated clinical studies in reducing Modic changes in the short term, but with unknown long-term benefits. New diagnostic tools and animal models are required to improve painful Modic change identification and classification, and to clarify the pathogenesis. Modic changes are likely to be more than just a coincidental imaging finding in LBP patients and rather represent an underlying pathology that should be a target for therapy.

The American Journal of Orthopedics, Mar 1, 2008

Orthopedics, Mar 1, 2006

The HKU Scholars Hub is the institutional repository of The University of Hong Kong. It seeks to ... more The HKU Scholars Hub is the institutional repository of The University of Hong Kong. It seeks to collect the intellectual output of HKU and make it available to the widest possible audience. Records are made in the Hub for items that are fulltext open access, or for URLs that hyperlink ...

Spine, Feb 1, 2010

Prospective, controlled, observational outcome study using clinical, radiographic, and patient/ph... more Prospective, controlled, observational outcome study using clinical, radiographic, and patient/physician-based questionnaire data, with patient outcomes at 12 months follow-up. To validate appropriateness criteria for low back surgery. Most surgical treatment failures are attributed to poor patient selection, but no widely accepted consensus exists on detailed indications for appropriate surgery. Appropriateness criteria for low back surgery have been developed by a multispecialty panel using the RAND appropriateness method. Based on panel criteria, a prospective study compared outcomes of patients appropriately and inappropriately treated at a single institution with 12 months follow-up assessment. Included were patients with low back pain and/or sciatica referred to the neurosurgical department. Information about symptoms, neurologic signs, the health-related quality of life (SF-36), disability status (Roland-Morris), and pain intensity (VAS) was assessed at baseline, at 6 months, and at 12 months follow-up. The appropriateness criteria were administered prospectively to each clinical situation and outside of the clinical setting, with the surgeon and patients blinded to the results of the panel decision. The patients were further stratified into 2 groups: appropriate treatment group (ATG) and inappropriate treatment group (ITG). Overall, 398 patients completed all forms at 12 months. Treatment was considered appropriate for 365 participants and inappropriate for 33 participants. The mean improvement in the SF-36 physical component score at 12 months was significantly higher in the ATG (mean: 12.3 points) than in the ITG (mean: 6.8 points) (P = 0.01), as well as the mean improvement in the SF-36 mental component score (ATG mean: 5.0 points; ITG mean: -0.5 points) (P = 0.02). Improvement was also significantly higher in the ATG for the mean VAS back pain (ATG mean: 2.3 points; ITG mean: 0.8 points; P = 0.02) and Roland-Morris disability score (ATG mean: 7.7 points; ITG mean: 4.2 points; P = 0.004). The ATG also had a higher improvement in mean VAS for sciatica (4.0 points) than the ITG (2.8 points), but the difference was not significant (P = 0.08). The SF-36 General Health score declined in both groups after 12 months, however, the decline was worse in the ITG (mean decline: 8.2 points) than in the ATG (mean decline: 1.2 points) (P = 0.04). Overall, in comparison to ITG patients, ATG patients had significantly higher improvement at 12 months, both statistically and clinically. In comparison to previously reported literature, our study is the first to assess the utility of appropriateness criteria for low back surgery at 1-year follow-up with multiple outcome dimensions. Our results confirm the hypothesis that application of appropriateness criteria can significantly improve patient outcomes.

The Journal of Bone and Joint Surgery American Volume, 2010

The fulcrum bending radiograph accurately predicts scoliosis curve correction in patients with th... more The fulcrum bending radiograph accurately predicts scoliosis curve correction in patients with thoracic adolescent idiopathic scoliosis who are managed with hooks. We assessed the predictive value of the fulcrum bending radiograph in the context of alternate-level pedicle screw fixation of the scoliotic spine. A prospective radiographic analysis of patients with thoracic adolescent idiopathic scoliosis who were managed operatively with alternate-level pedicle screw fixation at a single institution was performed. The Cobb angle was measured on posteroanterior standing coronal radiographs that were made preoperatively and one week postoperatively. The fulcrum flexibility percentage and the fulcrum bending correction index percentage were calculated. Forty-two patients were assessed. The mean age at the time of surgery was 14.6 years, and the mean number of fused levels was 9.4. On the preoperative radiographs, the mean values for the standing Cobb angle, the fulcrum bending radiograph Cobb angle, and fulcrum flexibility were 57.9 degrees, 21.8 degrees, and 62.7%, respectively. On the one-week postoperative radiographs, the mean Cobb angle was 15.4 degrees, the mean curve correction was 73.4%, and the mean fulcrum bending correction index was 122.1%. A significant, positive correlation was noted between the fulcrum bending radiograph angle and the fulcrum bending correction index, indicating that the fulcrum bending radiograph could predict the correction of flexible curves; however, for stiff curves, pedicle screws could provide more correction than the fulcrum bending radiograph predicted. To our knowledge, this is the first study to demonstrate the predictive value of the fulcrum bending radiograph in the context of alternate-level pedicle screw fixation in patients with adolescent idiopathic scoliosis. Curve flexibility may dictate the degree of the fulcrum bending correction index, whereby a curve that is less flexible may achieve a greater fulcrum bending correction index. The fulcrum bending radiograph has potential predictive utility. In addition, pedicle screw constructs appear to have a better ability to correct scoliosis in comparison with hooks and hybrid constructs.

The Spine Journal, 2010

« PreviousNext »The Spine Journal Volume 10, Issue 3 , Pages 277-278, March 2010. Spinal flexibil... more « PreviousNext »The Spine Journal Volume 10, Issue 3 , Pages 277-278, March 2010. Spinal flexibility in scoliosis: roots “bending” to antiquity. Dino Samartzis, DSc, PhD, MSc: Affiliations.Hong Kong, SAR China. email address ,; Frank La Marca, MD: Affiliations. MI, USA. ...

Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home > October ...

Spine J, 2008

... Powered by DSpace, version 1.6.2. Engineered by CILEA. This site implements DCMI Metadata thr... more ... Powered by DSpace, version 1.6.2. Engineered by CILEA. This site implements DCMI Metadata through meta-tags and an OAI-compliant repository located here. The University of Hong Kong Libraries, University of Hong Kong | Contact Us.

Annual Meeting of the International Society For the Study of the Lumbar Spine, Apr 11, 2014

ABSTRACT Study Design: Case-control studyObjective: The aim of this study was to define clinicall... more ABSTRACT Study Design: Case-control studyObjective: The aim of this study was to define clinically-relevant relative and critical (absolute) MRI values of lumbar spinal stenosis in a cohort of 100 surgical cases and 100 asymptomatic controls.Summary of Background Data: Developmental spinal stenosis is a precipitating factor in patients presenting with lumbar canal stenosis. Yet due to a lack of agreement on definitions and methods of assessment, as well as ethnic-specific normative values, its prevalence and significance is not known.Methods: This was a case-control study comparing 100 age and sex-matched asymptomatic, volunteers to that of 100 patients who underwent surgery for spinal stenosis. All patients were of Chinese ethnicity and their details were blinded to two observers. Spinal stenosis parameters were measured based on axial (pedicle level) and sagittal (mid-sagittal) MRI scans.Results: Anteroposterior (AP) spinal canal diameters changes with levels. At each level, patients were found to have significantly narrower AP canal diameters compared with controls. By use of receiver operating characteristic (ROC) curve, we defined developmental spinal stenosis if the AP canal diameter at L1&lt;20mm, L2&lt;19mm, L3&lt;19mm, L4&lt;17mm, L5&lt;16mm and at S1&lt;16mm based on a value including 50% of controls and demonstrated best sensitivity and specificity. Furthermore, for L4, L5 and S1, critical stenosis values could be defined, below which almost all subjects needed surgery, these were L4&lt;14mm, L5&lt;14mm and S1&lt;12mm.Conclusion: This is the largest MRI-based study with standardized measurements and comparable groups to determine clinically-relevant MRI criteria for lumbar spinal stenosis. The findings strongly suggest that developmental stenosis plays an important role in the pathogenesis of symptomatic spinal stenosis. Critical values of stenosis below which symptoms were highly likely were defined. These will need to be validated by longitudinal studies in future. However, they may possess clinical utility in determining the appropriate levels requiring canal-widening surgery.

A cross-sectional, population-based cohort study. The objective of this study was to evaluate the... more A cross-sectional, population-based cohort study. The objective of this study was to evaluate the clinical relevance of skipped level disc degeneration (SLDD) to that of contiguous, multilevel disc degeneration (CMDD) of the lumbar spine. The study also aimed to identify patterns of SLDD, its classification, prevalence, and clinical relevance. The association of disc degeneration on magnetic resonance imaging with low back pain (LBP) remains questionable. The occurrence of SLDD of the lumbar spine has recently been noted. To date, patterns of disc degeneration have been overlooked in the association with low back symptoms. A population-based radiographic and clinical study of 3099 Southern Chinese patients. Individuals with multilevel disc degeneration of the lumbar spine on sagittal T2-weighted magnetic resonance imaging (N = 1457) were stratified to SLDD (n = 301; 20.7%) or CMDD (n = 1156; 79.3%) groups. SLDD was further classified into 5 types by the relative location of nondegenerated normal disc(s) to degenerated disc levels. Subject demographics, presence of LBP, pain intensity, and functional disability were assessed. In the multivariate analyses, CMDD increased the likelihood of historical LBP (odds ratio [OR]: 1.39; 95% confidence interval [CI]: 1.00-1.93; P = 0.047) and pain severity (OR: 1.83; 95% CI: 1.23-2.73; P = 0.003) in comparison with SLDD. A significant increasing trend of number of levels with disc degeneration, overall disc degeneration severity, and presence of disc bulges/extrusions was noted from SLDD type I (least severe) to SLDD type V (most severe) (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). A higher prevalence of LBP and a higher pain intensity were observed in SLDD classification type V. Functional disability scores did not differ between CMDD and SLDD, nor within SLDD classification types (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Our large-scale study is the first to describe novel variants of SLDD types and their clinical relevance. More important, LBP and severity of pain were more pronounced in individuals with CMDD rather than those with SLDD. Our study suggests that subjects with a similar degree but different patterns of multilevel disc degeneration do differ with respect to low back symptoms. This finding may provide new evidence with regard to the mechanism of LBP.

The Spine Journal, 2015

Growing rods are commonly used for surgical treatment of skeletally immature patients with scolio... more Growing rods are commonly used for surgical treatment of skeletally immature patients with scoliosis, but require repeated surgeries for distractions and are fraught with complications. As an alternative, the use of magnetically-controlled growing rods (MCGR) allow for more frequent non-invasive distractions to mimic normal growth. However, more plain radiographs are needed to monitor increased distraction frequency, thereby increasing ionizing radiation exposure to the developing child. The use of ultrasound, which emits no radiation, has been found in a cross-sectional study to be reliable in measuring MCGR distractions. To address the prospective clinical utility of ultrasound compared to plain radiographs for assessing MCGR distractions. Prospective study. Early onset scoliosis patients undergoing distractions after MCGR implantation. Measured distraction length on plain radiographs and ultrasound. This is a prospective study of patients treated with MCGR. Patients with both single and dual rod systems were included. Out-patient distractions were performed at monthly intervals, targeting 2mm of distraction on each occasion. Assessment of distraction length was monitored by ultrasound at each visit, plain radiographs were taken every six months and compared with ultrasound measurements. Nine patients (5 females, 4 males) with a mean of 29 distractions (SD ±14.3) were recruited. The mean distracted length per 6-months was 5.7mm (SD ±3.6mm) on plain radiographs and 5.2mm (SD ±3.9mm) on ultrasound for the concave rod; and 6.1mm (SD ±3.6mm) on plain radiographs and 5.9mm (SD ±3.8mm) on ultrasound for the convex rod. Excellent inter- and intra-rator reliability was observed for radiographic and ultrasound measurements. Excellent correlation was noted between the two imaging modalities (r=0.93; p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). This is the first prospective study to validate that ultrasound assessment of MCGR distraction lengths was highly comparable to that of plain radiographs. This study has verified that the ultrasound can be used to document length changes by distraaction over time and had high clinical utility. Ultrasound can be a reliable alternative to plain radiographs; thereby, avoiding radiation exposure and its potential detrimental sequelae in the developing child.