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Papers by Nicholas Chua

Background: Percutaneous cervical nucleoplasty (PCN) is a safe and effective treatment in symptom... more Background: Percutaneous cervical nucleoplasty (PCN) is a safe and effective treatment in symptomatic patients with contained cervical herniated disks. It provides simple and efficient disk decompression, using a controlled and highly localized ablation, but evidence regarding long-term efficacy is limited. We conducted a retrospective study to investigate the long-term efficacy and safety of PCN, and the influence of ideal selection settings. Methods: A total of 27 patients treated with PCN fulfilling ideal selection criteria (Group A) were studied and compared to 42 patients not meeting these criteria (Group B). Outcomes were assessed using the Visual Analogue Scale (VAS) and a four-level Likert item for perceived pain and satisfaction, the Neck Disability Index (NDI), and the Short Form 36 (SF-36). Additional relevant outcomes were retrieved from medical records. Results: The postoperative mean VAS pain for Group A was 29.9 (SD ± 32.6) at a mean follow-up of 24 months (range: 2-45). Only 10% of these patients reported mild transient adverse events. There was a trend, but no difference between both groups in pain scores; however, treatment satisfaction was higher for Group A (74.1 ± 27.2-55.5 ± 31.4, P = 0.02). Group A also reported better physical functioning based on the Physical Component Summary (43.6 ± 10.6-37.3 ± 12.0, P = 0.03) and showed a larger proportion of patients no longer using any medication postoperatively (63-26%, P = 0.01). Conclusion: These results show long-term effectiveness and safety of PCN in patients with a one-level contained cervical herniated disk, and the reliance of selecting patients meeting ideal criteria for successful PCN. &

Asian Spine Journal, 2011

Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five ... more Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five of every 1,000 disc herniations encountered in the clinical setting [1]. Majority of thoracic disc herniations are asymptomatic [2], with radicular chest pain being the most common presenting complaint. Few patients require invasive treatments and most conservatively treated patients eventually returned to the prior level of activity [3]. Earlier cases that require surgical intervention required a dorsal surgical approach which was associated with significant complications of irreversible paraplegia and operative mortalities approaching 10% [4]. Current surgical techniques have demonstrated significant improvements in the postoperative critical care requirements and discharge times. However, these techniques all require general anesthesia and in many instances, one-lung ventilation. Furthermore, added neurological complications, pneumothorax, blood loss and surgical wound infection are all inherent surgical complications. There is also a significant risk of intercostal neuralgia as reported by Rosenthal and Dickman [5]: 16% in thoracoscopy, 20% when via costotransversectomy

Pain Practice, Mar 2, 2010

The lateral atlantoaxial joint has long been reported as a source of cervicogenic headache. We pr... more The lateral atlantoaxial joint has long been reported as a source of cervicogenic headache. We present a retrospective study, including 86 patients who had undergone lateral C1-2 joint pulsed radiofrequency application, for cervicogenic headache in a single pain center from March 2007 to December 2008. The percentage of patients who had 350% pain relief at 2 months, 6 months, and 1 year were 50% (43/86), 50% (43/86), and 44.2% (38/86), respectively. Longterm pain relief at 6 months and 1 year were predicted reliably by Ն50% pain relief at 2 months (P < 0.001). Apart from 1 patient that complained of increased severity of occipital headache lasting several hours, we had no other reported complications.

European Journal of Pain, May 1, 2011

Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;... more Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;15(5):540-1; author reply 542-3. Epub 2011 Mar 21.

Pain Practice, Mar 16, 2011

Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency... more Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency thermocoagulation for the management of certain chronic pain syndromes. We present our first three patients with long-standing cluster headaches who were treated with pulsed radiofrequency to the sphenopalatine ganglion. All three patients have had cluster headaches for more than 10 years' duration and experienced minimal relief with conservative treatment. An excellent midterm effect was achieved in two of the three patients and a partial effect in one. No neurological side effects or complications were reported. Quantitative sensory testing consisting of allodynia testing, pressure-pain thresholds, electrical pain thresholds, and conditioned pain modulation (CPM) response testing were used to monitor their sensory processing changes before and after the procedure. From this case series, it might be that cluster headache patients with an impaired CPM response with or without signs of allodynia will respond less favorably to interventional treatment. Further studies are required to validate this hypothesis.

Anesthesiology and Pain Medicine, Jan 19, 2012

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%.

Acta neurochirurgica, Nov 30, 2010

Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF... more Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality. Methods We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al. Findings We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain. Conclusion From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques.

Annals Academy of Medicine Singapore, Nov 15, 2010

Regional Anesthesia and Pain Medicine, Jul 1, 2011

Background and Objectives: Diagnostic blocks of cervical zygapophysial joints have been used as p... more Background and Objectives: Diagnostic blocks of cervical zygapophysial joints have been used as part of the management strategy for patients with chronic neck pain. Little information is available regarding the sensory processing changes that occur after these common procedures. In a hypothesis-generating prospective study, the pressurepain thresholds, electrical pain thresholds, and descending inhibitory modulation response using the conditioned pain modulation paradigm are described for 9 patients with cervical zygapophysial joint pain that underwent successful comparative diagnostic blocks. Methods: The study was designed as a prospective cross-sectional study in 9 patients with cervical zygapophysial joint pain with positive comparative diagnostic blocks using lidocaine and bupivacaine. Each patient underwent baseline Quantitative Sensory Testing (QST) measurement (QST 1) after inclusion. Subsequent QST measurements (QST 2 and 3) were performed only after comparative blocks proved positive and only after the neck pain returned after each diagnostic block. Results: Despite the return of their neck pain after the local anesthetic agents wore off, the patients exhibited (1) less focal pressure hyperalgesia, (2) generalized electrical hypoalgesia, and (3) significantly reduced conditioned pain modulation responses.

Medical Research Archives

Lumbar epidural spinal cord stimulation (SCS) was used to improve motor function in a 50-yr old p... more Lumbar epidural spinal cord stimulation (SCS) was used to improve motor function in a 50-yr old patient who suffered hemiparesis due to a basal ganglia haemorrhagic stroke. Spinal cord stimulation targeted at the dorsal root afferent fibres at the conus improved the tonic control of the muscles at the knee and ankle joints. This allowed the patient better left knee and foot motor control. The improvement was documented initially during ambulation on a treadmill using decreasing body weight support and subsequently when using walking aids. Our observation is consistent with previous human data suggesting that in humans with brain lesions, the stimulation of preserved neural circuitry can increase spontaneous muscle tone in affected muscles and improve locomotion. Article Details How to Cite CHUA, Nicholas HL; JOHN, Thomas; BUCHSER, Eric. Epidural Stimulation of the Lumbosacral Spinal Cord After Basal Ganglia Haemorrhage: A Case Study. Medical Research Archives, [S.l.], v. 11, n. 3, m...

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%. Background: Whiplash patients regard cervicogenic headache (CEH) as the most burdensome symptom of their condition. Sufferers experience a significant degree of disability from headache, associated neck pain and disability, and sleep disturbance. Lateral C1/2 joint pulsed radiofrequency (PRF) treatment has been shown to produce significant relief from headache in patients with CEH. Objectives: The objective of this retrospective questionnaire study of 45 consecutive whiplash patients with CEH who had undergone antero-lateral atlantoaxial joint pulsed radiofrequency treatment (AA PRF) was to evaluate the treatment's long-term effects on painrelated disability and health-related quality of life. Patients and Methods: Four questionnaires were sent to all 45 patients who had undergone AA PRF: 1) The short form-36 (SF-36); 2) The neck disability index (NDI); 3) The medical outcome scale-sleep scale (MOS-SS); 4) The headache impact test-6 (HIT-6). All 45 patients received AA PRF under fluoroscopic guidance. PRF treatment was conducted at 45 V with a pulsed frequency of 4 Hz and a pulsed width of 10 ms for 4 minutes. Results: Patients who responded to the procedure reported lower pain scores at 2, 6, and 12 months of follow-up compared to nonresponders. More important, patients reported marked improvements in headache impact (P < 0.01), neck-disability scores (P < 0.01), awakening due to headache (P < 0.01), and sleep problems (9-item; P < 0.05) on the MOS-SS. Responders to the procedure also reported a significantly higher health-related quality of life in terms of bodily pain (P < 0.05) and health change (P < 0.01) on the SF-36. Conclusions: In light of the inherent limitations of our retrospective study, AA PRF treatment can only be tentatively viewed as a promising treatment modality for whiplash patients with CEH and is subject to validation in future studies.

Implication for health policy/practice/research/medical education: Whiplash associated disorders ... more Implication for health policy/practice/research/medical education: Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%. 1. Background The term cervicogenic headache (CEH) was first coined by Sjaastad et al. in 1983. In 1990 the CHISG criteria (cer-vicogenic headache international study group) for CEH was issued (1). Whiplash injuries were later implicated as likely triggers of CEH (1). Whiplash-associated disorders Background: Whiplash patients regard cervicogenic headache (CEH) as the most burden-some symptom of their condition. Sufferers experience a significant degree of disability from headache, associated neck pain and disability, and sleep disturbance. Lateral C1/2 joint pulsed radiofrequency (PRF) treatment has been shown to produce significant relief from headache in patients with CEH. Objectives: The objective of this retrospective quest...

Asian Spine Journal, 2011

Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five ... more Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five of every 1,000 disc herniations encountered in the clinical setting [1]. Majority of thoracic disc herniations are asymptomatic [2], with radicular chest pain being the most common presenting complaint. Few patients require invasive treatments and most conservatively treated patients eventually returned to the prior level of activity [3]. Earlier cases that require surgical intervention required a dorsal surgical approach which was associated with significant complications of irreversible paraplegia and operative mortalities approaching 10% [4]. Current surgical techniques have demonstrated significant improvements in the postoperative critical care requirements and discharge times. However, these techniques all require general anesthesia and in many instances, one-lung ventilation. Furthermore, added neurological complications, pneumothorax, blood loss and surgical wound infection are all inherent surgical complications. There is also a significant risk of intercostal neuralgia as reported by Rosenthal and Dickman [5]: 16% in thoracoscopy, 20% when via costotransversectomy

Anesthesiology and Pain Medicine, 2012

Trigeminal neuralgia is one of the most severe forms of facial pain known to man. PRF treatment o... more Trigeminal neuralgia is one of the most severe forms of facial pain known to man. PRF treatment of the trigeminal ganglion is a possible minimally invasive treatment alternative. There are possibilities of avoiding ablation-related complications using this technique but this will need to be evaluated in greater detail in further studies. Background: Pulsed radiofrequency (PRF) treatment is defined as the delivery of short pulses of radiofrequency via a needle tip, which does not result in an actual thermal lesions. There are mixed views regarding the use of PRF for trigeminal neuralgia (TN). In our opinion, one of the main reasons for the contrasting views is the insufficient PRF dose employed in previous studies. In a recent study on the effects of PRF on resiniferatoxininduced neuropathic pain in an animal model, the anti-allodynic effects of PRF were significantly greater when the PRF exposure duration was increased from 2 to 6 minutes. Objectives: The primary objective of this retrospective study is to report the results for 36 consecutive patients who underwent PRF treatment for TN, for 6 minutes at 45 V at a pulsed frequency of 4 Hz and a pulse width of 10 ms. Patients and Methods: For the study, we obtained procedural records of 36 consecutive patients. Their current state of pain was evaluated over a telephonic survey and the post-procedural data at 2, 6, and 12 months were retrieved thereafter from the patient records. The main outcome measure was excellent pain relief (more than 80%), which was assessed at 2, 6, and 12 months. Results: The percentages of patients who showed excellent pain relief (> 80% pain relief) at 2, 6, and 12 months were 73.5% (25/34), 61.8% (21/34), and 55.9% (19/34), respectively. The percentages of patients showing satisfactory pain relief (50-80% pain relief) at 2, 6, and 12 months were 14.7% (5/34), 17.6% (6/34), and 17.6% (6/34), respectively, and those of patients showing less than satisfactory pain relief (< 50% pain relief) at 2, 6, and 12 months were 11.8% (4/34), 20.6% (7/34), and 23.5% (8/34), respectively. No complications were reported, and none of the patients required hospitalization. Conclusions: PRF of the trigeminal ganglion should be further evaluated as an alternative treatment method for TN.

Anesthesiology and Pain Medicine, 2012

Understanding the mechanisms underlying the development of CEH is important because it will not o... more Understanding the mechanisms underlying the development of CEH is important because it will not only provide a better treatment outcome but will also allow practitioners to appreciate the variability of symptomatic presentations in these patients.

Acta Neurochirurgica, 2010

Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF... more Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality. Methods We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al. Findings We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain. Conclusion From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques.

Anesthesiology and Pain Medicine, 2012

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%.

Pain Practice, 2011

Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency... more Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency thermocoagulation for the management of certain chronic pain syndromes. We present our first three patients with long-standing cluster headaches who were treated with pulsed radiofrequency to the sphenopalatine ganglion. All three patients have had cluster headaches for more than 10 years' duration and experienced minimal relief with conservative treatment. An excellent midterm effect was achieved in two of the three patients and a partial effect in one. No neurological side effects or complications were reported. Quantitative sensory testing consisting of allodynia testing, pressure-pain thresholds, electrical pain thresholds, and conditioned pain modulation (CPM) response testing were used to monitor their sensory processing changes before and after the procedure. From this case series, it might be that cluster headache patients with an impaired CPM response with or without signs of allodynia will respond less favorably to interventional treatment. Further studies are required to validate this hypothesis.

European Journal of Pain, 2011

Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;... more Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;15(5):540-1; author reply 542-3. Epub 2011 Mar 21.

Pain Management, 2012

191 ISSN 1758-1869 10.2217/PMT.12.10 © 2012 Future Medicine Ltd Pain Manage. (2012) 2(3), 191–194... more 191 ISSN 1758-1869 10.2217/PMT.12.10 © 2012 Future Medicine Ltd Pain Manage. (2012) 2(3), 191–194 Headache arising from cervical spine pathologies remains one of the most debated areas in headache medicine. The absence of a clear distinction between migraine and cervicogenic headache (CEH), as well as the lack of ‘diagnostic markers’ for CEH are among the main reasons [1]. One important biological marker for migraine is a focal increase in CGRP [2]. CGRP measurements performed in patients with CEH showed no detectable trigeminovascular activation and it is most likely that CEH is biologically different from migraine and not just a migraine variant triggered by neck dysfunction [3]. The following paragraphs discuss the rationale of the neck being a valid pain generator for the head from the basis of neurophysiological pathways, topographical pain mapping experiments and treatment observations, and also highlights the important facilitatory role of the lower cervical segments. Potential nociceptive structures in the neck The weight of the head and the mobility of the neck are key factors in the susceptibility of the cervical spine to injury. Even in younger patients, the presence of degenerative changes in the cervical spine, although often asymptomatic, highlights the amount of mechanical load placed on the neck. Many structures in the neck have a rich nociceptive neural network. These include structures such as the zygapophysial joints, intervertebral discs, ligaments, muscles, as well as the overlying skin. Of these, the zygapophysial joints and the intervertebral discs appear to be the most important pain generators [1]. Furthermore, clinical studies have also revealed that the zygapophysial joints are the most likely to be injured following whiplash injuries [4]. In addition, biomechanical data also point towards an increased likelihood of injury

Background: Percutaneous cervical nucleoplasty (PCN) is a safe and effective treatment in symptom... more Background: Percutaneous cervical nucleoplasty (PCN) is a safe and effective treatment in symptomatic patients with contained cervical herniated disks. It provides simple and efficient disk decompression, using a controlled and highly localized ablation, but evidence regarding long-term efficacy is limited. We conducted a retrospective study to investigate the long-term efficacy and safety of PCN, and the influence of ideal selection settings. Methods: A total of 27 patients treated with PCN fulfilling ideal selection criteria (Group A) were studied and compared to 42 patients not meeting these criteria (Group B). Outcomes were assessed using the Visual Analogue Scale (VAS) and a four-level Likert item for perceived pain and satisfaction, the Neck Disability Index (NDI), and the Short Form 36 (SF-36). Additional relevant outcomes were retrieved from medical records. Results: The postoperative mean VAS pain for Group A was 29.9 (SD ± 32.6) at a mean follow-up of 24 months (range: 2-45). Only 10% of these patients reported mild transient adverse events. There was a trend, but no difference between both groups in pain scores; however, treatment satisfaction was higher for Group A (74.1 ± 27.2-55.5 ± 31.4, P = 0.02). Group A also reported better physical functioning based on the Physical Component Summary (43.6 ± 10.6-37.3 ± 12.0, P = 0.03) and showed a larger proportion of patients no longer using any medication postoperatively (63-26%, P = 0.01). Conclusion: These results show long-term effectiveness and safety of PCN in patients with a one-level contained cervical herniated disk, and the reliance of selecting patients meeting ideal criteria for successful PCN. &

Asian Spine Journal, 2011

Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five ... more Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five of every 1,000 disc herniations encountered in the clinical setting [1]. Majority of thoracic disc herniations are asymptomatic [2], with radicular chest pain being the most common presenting complaint. Few patients require invasive treatments and most conservatively treated patients eventually returned to the prior level of activity [3]. Earlier cases that require surgical intervention required a dorsal surgical approach which was associated with significant complications of irreversible paraplegia and operative mortalities approaching 10% [4]. Current surgical techniques have demonstrated significant improvements in the postoperative critical care requirements and discharge times. However, these techniques all require general anesthesia and in many instances, one-lung ventilation. Furthermore, added neurological complications, pneumothorax, blood loss and surgical wound infection are all inherent surgical complications. There is also a significant risk of intercostal neuralgia as reported by Rosenthal and Dickman [5]: 16% in thoracoscopy, 20% when via costotransversectomy

Pain Practice, Mar 2, 2010

The lateral atlantoaxial joint has long been reported as a source of cervicogenic headache. We pr... more The lateral atlantoaxial joint has long been reported as a source of cervicogenic headache. We present a retrospective study, including 86 patients who had undergone lateral C1-2 joint pulsed radiofrequency application, for cervicogenic headache in a single pain center from March 2007 to December 2008. The percentage of patients who had 350% pain relief at 2 months, 6 months, and 1 year were 50% (43/86), 50% (43/86), and 44.2% (38/86), respectively. Longterm pain relief at 6 months and 1 year were predicted reliably by Ն50% pain relief at 2 months (P < 0.001). Apart from 1 patient that complained of increased severity of occipital headache lasting several hours, we had no other reported complications.

European Journal of Pain, May 1, 2011

Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;... more Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;15(5):540-1; author reply 542-3. Epub 2011 Mar 21.

Pain Practice, Mar 16, 2011

Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency... more Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency thermocoagulation for the management of certain chronic pain syndromes. We present our first three patients with long-standing cluster headaches who were treated with pulsed radiofrequency to the sphenopalatine ganglion. All three patients have had cluster headaches for more than 10 years' duration and experienced minimal relief with conservative treatment. An excellent midterm effect was achieved in two of the three patients and a partial effect in one. No neurological side effects or complications were reported. Quantitative sensory testing consisting of allodynia testing, pressure-pain thresholds, electrical pain thresholds, and conditioned pain modulation (CPM) response testing were used to monitor their sensory processing changes before and after the procedure. From this case series, it might be that cluster headache patients with an impaired CPM response with or without signs of allodynia will respond less favorably to interventional treatment. Further studies are required to validate this hypothesis.

Anesthesiology and Pain Medicine, Jan 19, 2012

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%.

Acta neurochirurgica, Nov 30, 2010

Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF... more Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality. Methods We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al. Findings We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain. Conclusion From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques.

Annals Academy of Medicine Singapore, Nov 15, 2010

Regional Anesthesia and Pain Medicine, Jul 1, 2011

Background and Objectives: Diagnostic blocks of cervical zygapophysial joints have been used as p... more Background and Objectives: Diagnostic blocks of cervical zygapophysial joints have been used as part of the management strategy for patients with chronic neck pain. Little information is available regarding the sensory processing changes that occur after these common procedures. In a hypothesis-generating prospective study, the pressurepain thresholds, electrical pain thresholds, and descending inhibitory modulation response using the conditioned pain modulation paradigm are described for 9 patients with cervical zygapophysial joint pain that underwent successful comparative diagnostic blocks. Methods: The study was designed as a prospective cross-sectional study in 9 patients with cervical zygapophysial joint pain with positive comparative diagnostic blocks using lidocaine and bupivacaine. Each patient underwent baseline Quantitative Sensory Testing (QST) measurement (QST 1) after inclusion. Subsequent QST measurements (QST 2 and 3) were performed only after comparative blocks proved positive and only after the neck pain returned after each diagnostic block. Results: Despite the return of their neck pain after the local anesthetic agents wore off, the patients exhibited (1) less focal pressure hyperalgesia, (2) generalized electrical hypoalgesia, and (3) significantly reduced conditioned pain modulation responses.

Medical Research Archives

Lumbar epidural spinal cord stimulation (SCS) was used to improve motor function in a 50-yr old p... more Lumbar epidural spinal cord stimulation (SCS) was used to improve motor function in a 50-yr old patient who suffered hemiparesis due to a basal ganglia haemorrhagic stroke. Spinal cord stimulation targeted at the dorsal root afferent fibres at the conus improved the tonic control of the muscles at the knee and ankle joints. This allowed the patient better left knee and foot motor control. The improvement was documented initially during ambulation on a treadmill using decreasing body weight support and subsequently when using walking aids. Our observation is consistent with previous human data suggesting that in humans with brain lesions, the stimulation of preserved neural circuitry can increase spontaneous muscle tone in affected muscles and improve locomotion. Article Details How to Cite CHUA, Nicholas HL; JOHN, Thomas; BUCHSER, Eric. Epidural Stimulation of the Lumbosacral Spinal Cord After Basal Ganglia Haemorrhage: A Case Study. Medical Research Archives, [S.l.], v. 11, n. 3, m...

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%. Background: Whiplash patients regard cervicogenic headache (CEH) as the most burdensome symptom of their condition. Sufferers experience a significant degree of disability from headache, associated neck pain and disability, and sleep disturbance. Lateral C1/2 joint pulsed radiofrequency (PRF) treatment has been shown to produce significant relief from headache in patients with CEH. Objectives: The objective of this retrospective questionnaire study of 45 consecutive whiplash patients with CEH who had undergone antero-lateral atlantoaxial joint pulsed radiofrequency treatment (AA PRF) was to evaluate the treatment's long-term effects on painrelated disability and health-related quality of life. Patients and Methods: Four questionnaires were sent to all 45 patients who had undergone AA PRF: 1) The short form-36 (SF-36); 2) The neck disability index (NDI); 3) The medical outcome scale-sleep scale (MOS-SS); 4) The headache impact test-6 (HIT-6). All 45 patients received AA PRF under fluoroscopic guidance. PRF treatment was conducted at 45 V with a pulsed frequency of 4 Hz and a pulsed width of 10 ms for 4 minutes. Results: Patients who responded to the procedure reported lower pain scores at 2, 6, and 12 months of follow-up compared to nonresponders. More important, patients reported marked improvements in headache impact (P < 0.01), neck-disability scores (P < 0.01), awakening due to headache (P < 0.01), and sleep problems (9-item; P < 0.05) on the MOS-SS. Responders to the procedure also reported a significantly higher health-related quality of life in terms of bodily pain (P < 0.05) and health change (P < 0.01) on the SF-36. Conclusions: In light of the inherent limitations of our retrospective study, AA PRF treatment can only be tentatively viewed as a promising treatment modality for whiplash patients with CEH and is subject to validation in future studies.

Implication for health policy/practice/research/medical education: Whiplash associated disorders ... more Implication for health policy/practice/research/medical education: Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%. 1. Background The term cervicogenic headache (CEH) was first coined by Sjaastad et al. in 1983. In 1990 the CHISG criteria (cer-vicogenic headache international study group) for CEH was issued (1). Whiplash injuries were later implicated as likely triggers of CEH (1). Whiplash-associated disorders Background: Whiplash patients regard cervicogenic headache (CEH) as the most burden-some symptom of their condition. Sufferers experience a significant degree of disability from headache, associated neck pain and disability, and sleep disturbance. Lateral C1/2 joint pulsed radiofrequency (PRF) treatment has been shown to produce significant relief from headache in patients with CEH. Objectives: The objective of this retrospective quest...

Asian Spine Journal, 2011

Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five ... more Symptomatic thoracic disc herniation is an uncommon condition, accounting for approximately five of every 1,000 disc herniations encountered in the clinical setting [1]. Majority of thoracic disc herniations are asymptomatic [2], with radicular chest pain being the most common presenting complaint. Few patients require invasive treatments and most conservatively treated patients eventually returned to the prior level of activity [3]. Earlier cases that require surgical intervention required a dorsal surgical approach which was associated with significant complications of irreversible paraplegia and operative mortalities approaching 10% [4]. Current surgical techniques have demonstrated significant improvements in the postoperative critical care requirements and discharge times. However, these techniques all require general anesthesia and in many instances, one-lung ventilation. Furthermore, added neurological complications, pneumothorax, blood loss and surgical wound infection are all inherent surgical complications. There is also a significant risk of intercostal neuralgia as reported by Rosenthal and Dickman [5]: 16% in thoracoscopy, 20% when via costotransversectomy

Anesthesiology and Pain Medicine, 2012

Trigeminal neuralgia is one of the most severe forms of facial pain known to man. PRF treatment o... more Trigeminal neuralgia is one of the most severe forms of facial pain known to man. PRF treatment of the trigeminal ganglion is a possible minimally invasive treatment alternative. There are possibilities of avoiding ablation-related complications using this technique but this will need to be evaluated in greater detail in further studies. Background: Pulsed radiofrequency (PRF) treatment is defined as the delivery of short pulses of radiofrequency via a needle tip, which does not result in an actual thermal lesions. There are mixed views regarding the use of PRF for trigeminal neuralgia (TN). In our opinion, one of the main reasons for the contrasting views is the insufficient PRF dose employed in previous studies. In a recent study on the effects of PRF on resiniferatoxininduced neuropathic pain in an animal model, the anti-allodynic effects of PRF were significantly greater when the PRF exposure duration was increased from 2 to 6 minutes. Objectives: The primary objective of this retrospective study is to report the results for 36 consecutive patients who underwent PRF treatment for TN, for 6 minutes at 45 V at a pulsed frequency of 4 Hz and a pulse width of 10 ms. Patients and Methods: For the study, we obtained procedural records of 36 consecutive patients. Their current state of pain was evaluated over a telephonic survey and the post-procedural data at 2, 6, and 12 months were retrieved thereafter from the patient records. The main outcome measure was excellent pain relief (more than 80%), which was assessed at 2, 6, and 12 months. Results: The percentages of patients who showed excellent pain relief (> 80% pain relief) at 2, 6, and 12 months were 73.5% (25/34), 61.8% (21/34), and 55.9% (19/34), respectively. The percentages of patients showing satisfactory pain relief (50-80% pain relief) at 2, 6, and 12 months were 14.7% (5/34), 17.6% (6/34), and 17.6% (6/34), respectively, and those of patients showing less than satisfactory pain relief (< 50% pain relief) at 2, 6, and 12 months were 11.8% (4/34), 20.6% (7/34), and 23.5% (8/34), respectively. No complications were reported, and none of the patients required hospitalization. Conclusions: PRF of the trigeminal ganglion should be further evaluated as an alternative treatment method for TN.

Anesthesiology and Pain Medicine, 2012

Understanding the mechanisms underlying the development of CEH is important because it will not o... more Understanding the mechanisms underlying the development of CEH is important because it will not only provide a better treatment outcome but will also allow practitioners to appreciate the variability of symptomatic presentations in these patients.

Acta Neurochirurgica, 2010

Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF... more Background The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality. Methods We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al. Findings We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain. Conclusion From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques.

Anesthesiology and Pain Medicine, 2012

Whiplash associated disorders are very costly to any healthcare structure, whatever the policy th... more Whiplash associated disorders are very costly to any healthcare structure, whatever the policy that shapes it. The prevalence of cervicogenic headache in whiplash injuries are as high as 53%.

Pain Practice, 2011

Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency... more Pulsed radiofrequency treatment has been described as a nonablative alternative to radiofrequency thermocoagulation for the management of certain chronic pain syndromes. We present our first three patients with long-standing cluster headaches who were treated with pulsed radiofrequency to the sphenopalatine ganglion. All three patients have had cluster headaches for more than 10 years' duration and experienced minimal relief with conservative treatment. An excellent midterm effect was achieved in two of the three patients and a partial effect in one. No neurological side effects or complications were reported. Quantitative sensory testing consisting of allodynia testing, pressure-pain thresholds, electrical pain thresholds, and conditioned pain modulation (CPM) response testing were used to monitor their sensory processing changes before and after the procedure. From this case series, it might be that cluster headache patients with an impaired CPM response with or without signs of allodynia will respond less favorably to interventional treatment. Further studies are required to validate this hypothesis.

European Journal of Pain, 2011

Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;... more Chua, Nicholas H L Vissers, Kris C Wilder-Smith, O H Comment Letter England Eur J Pain. 2011 May;15(5):540-1; author reply 542-3. Epub 2011 Mar 21.

Pain Management, 2012

191 ISSN 1758-1869 10.2217/PMT.12.10 © 2012 Future Medicine Ltd Pain Manage. (2012) 2(3), 191–194... more 191 ISSN 1758-1869 10.2217/PMT.12.10 © 2012 Future Medicine Ltd Pain Manage. (2012) 2(3), 191–194 Headache arising from cervical spine pathologies remains one of the most debated areas in headache medicine. The absence of a clear distinction between migraine and cervicogenic headache (CEH), as well as the lack of ‘diagnostic markers’ for CEH are among the main reasons [1]. One important biological marker for migraine is a focal increase in CGRP [2]. CGRP measurements performed in patients with CEH showed no detectable trigeminovascular activation and it is most likely that CEH is biologically different from migraine and not just a migraine variant triggered by neck dysfunction [3]. The following paragraphs discuss the rationale of the neck being a valid pain generator for the head from the basis of neurophysiological pathways, topographical pain mapping experiments and treatment observations, and also highlights the important facilitatory role of the lower cervical segments. Potential nociceptive structures in the neck The weight of the head and the mobility of the neck are key factors in the susceptibility of the cervical spine to injury. Even in younger patients, the presence of degenerative changes in the cervical spine, although often asymptomatic, highlights the amount of mechanical load placed on the neck. Many structures in the neck have a rich nociceptive neural network. These include structures such as the zygapophysial joints, intervertebral discs, ligaments, muscles, as well as the overlying skin. Of these, the zygapophysial joints and the intervertebral discs appear to be the most important pain generators [1]. Furthermore, clinical studies have also revealed that the zygapophysial joints are the most likely to be injured following whiplash injuries [4]. In addition, biomechanical data also point towards an increased likelihood of injury