Radiation therapy with phenotypic medicine: towards N-of-1 personalization

In current clinical practice, radiotherapy (RT) is prescribed as a pre-determined total dose divided over daily doses (fractions) given over several weeks. The treatment response is typically assessed months after the end of RT. However, the conventional one-dose-fits-all strategy may not achieve the desired outcome, owing to patient and tumor heterogeneity. Therefore, a treatment strategy that allows for RT dose personalization based on each individual response is preferred. Multiple strategies have been adopted to address this challenge. As an alternative to current known strategies, artificial intelligence (AI)-derived mechanism-independent small data phenotypic medicine (PM) platforms may be utilized for N-of-1 RT personalization. Unlike existing big data approaches, PM does not engage in model refining, training, and validation, and guides treatment by utilizing prospectively collected patient's own small datasets. With PM, clinicians may guide patients' RT dose recommendations using their responses in real-time and potentially avoid over-treatment in good responders and under-treatment in poor responders. In this paper, we discuss the potential of engaging PM to guide clinicians on upfront dose selections and ongoing adaptations during RT, as well as considerations and limitations for implementation. For practicing oncologists, clinical trialists, and researchers, PM can either be implemented as a standalone strategy or in complement with other existing RT personalizations. In addition, PM can either be used for monotherapeutic RT personalization, or in combination with other therapeutics (e.g. chemotherapy, targeted therapy). The potential of N-of-1 RT personalization with drugs will also be presented.

PRECISE CURATE.AI: A prospective feasibility trial to dynamically modulate personalized chemotherapy dose with artificial intelligence

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Background: Most treatment guidelines recommend chemotherapy at maximum tolerated doses, which does not always lead to optimal efficacy, but implicitly results in toxicity. To overcome this challenge, we developed CURATE.AI, a small data, AI-derived platform that harnesses only a patient’s own prospectively/longitudinally acquired data to dynamically identify their own optimal and personalized doses. We subsequently harnessed CURATE.AI to dynamically modulate individualized chemotherapy doses for patients in a prospective clinical trial. Methods: We conducted an open-label, multi-center, single-arm, prospective feasibility trial in patients diagnosed with advanced solid tumors and treated with single-agent capecitabine, XELOX or XELIRI (+/- biologics) (NCT04522284). The standard-of-care (SOC) capecitabine dose was 1000 mg/m2, unless adjusted by clinician to account for patient’s comorbidities and organ dysfunction. Using an AI-discovered second-order correlation between patient-specific variation of capecitabine doses and corresponding tumor marker (CEA, CA19-9 or CA-125) readouts for each cycle, CURATE.AI generated individualized patient digital avatars and recommended bespoke dose for the subsequent cycle. The clinicians were permitted to accept CURATE.AI dose recommendations, or reject the recommendations and dose based on clinical judgement. Results: Since August 2020 we recruited ten patients: single-agent capecitabine (n = 1), XELOX (n = 6), and XELIRI (n = 3). As of 20 Jan 2022, one patient remains on the trial. The prescribed dose was on average reduced by 20 % (± 13.8 %) as compared to the projected SOC dose. The nine reported patients completed 3.9 cycles (± 2.2 cycles), with the longest participation lasting 8 cycles. CURATE.AI recommendations were considered in 27 out of 40 total dosing decisions and accepted for prescription in 26 of those decisions. The reasons for not considering CURATE.AI included insufficient time from patient recruitment to the first dose administration and complex medical circumstances at the time of the dosing decisions. Conclusions: CURATE.AI has been successfully incorporated into the clinical workflow of dynamic dose selection in the treatment of solid tumors under a clinical trial. Prospective validation of CURATE.AI led to a reduction of an average prescribed capecitabine dose, which alongside additional preliminary findings may eventually play an important role in improving patient response rates and durations compared to SOC. Results from the PRECISE CURATE.AI trial support the initiation of a randomized clinical trial and potential expansion towards other oncologic indications. Clinical trial information: NCT04522284.

Effects of vitamin B fortified sucrose solution on the longevity and reproductive potentials of laboratory-bred Culex quinquefasciatus Say adult

Laboratory colonised mosquitoes are usually maintained on vitamin B complex fortified sucrose solution, however only few studies were conducted to evaluate the effects of such practice. This study aimed to determine the effects of different concentrations of sucrose solution fortified with and without 1% vitamin B complex on the longevity and reproductive potential of adult female of a local strain of Culex quinquefasciatus Say. Two arms of studies were carried out separately and each arm was triplicated. In one arm, concentrations of sucrose solution at 0%, 1%, 3%, 5% and 10% fortified with 1% Vitamin B complex were fed to the mosquitoes, while in the other arm, similar sucrose concentrations were used but without 1% vitamin B complex. Adult Cx. quinquefasciatus maintained on 5% sucrose solution fortified with 1% vitamin B complex exhibited significant extended vitality and longevity in stimulating ovarian development, compared with other vitamin fortified sucrose concentrations (p<0.05). The vitality and longevity of F0 and F1 males were 76.67±2.19 days and 57.67±8.19 days respectively. The F0 females survived the longest duration of 107.67±5.61 days and the F1 females survived 90.67±12.47 days with higher number of eggs laid, i.e. 1427.67±62.89 eggs at a higher hatchability rate of 57.05±8.39% or 814.49 eggs hatched. Thus, 5% sucrose solution fortified with 1% Vitamin B complex should be used to produce colonies of homogenous mosquitoes as this exerts positive biological effects on laboratory-bred Cx. quinquefasciatus.

Adjuvant hepatic intra-arterial iodine-131-lipiodol following curative resection of hepatocellular carcinoma: a prospective randomized trial

BACKGROUND

The purpose of the present study was to determine whether intrahepatic injection of (131)I-lipiodol (Lipiodol) is effective against recurrence of surgically resected hepatocellular carcinoma (HCC).

METHODS

From June 2001 through March 2007, this nationwide multi-center prospective randomized controlled trial enrolled 103 patients 4-6 weeks after curative resection of HCC with complete recovery (52: Lipiodol, 51: Control). Follow-up was every 3 months for 1 year, then every 6 months. Primary and secondary endpoints were recurrence-free survival (RFS) and overall survival (OS), respectively, both of which were evaluated by the Kaplan-Meier technique and summarized by the hazard ratio (HR). The design was based on information obtained from a similar trial that had been conducted in Hong Kong.

RESULTS

The Lipiodol group showed a small, and nonsignificant, improvement over control in RFS (HR = 0.75; 95 % confidence interval [95 % CI] 0.46-1.23; p = 0.25) and OS (HR = 0.88; 95 % CI 0.51-1.51; p = 0.64). Only two serious adverse events were reported, both with hypothyroidism caused by (131)I-lipiodol and hepatic artery dissection during angiography.

CONCLUSIONS

The randomized trial provides insufficient evidence to recommend the routine use of (131)I-lipiodol in these patients.

In vitro antibacterial activity and physicochemical properties of a crude methanol extract of the larvae of the blow fly Lucilia cuprina

The emergence of multidrug-resistant bacterial strains has prompted the reintroduction of maggot therapy in the treatment of chronic, infected wounds. Many previous studies have demonstrated the potent antibacterial activity of larval excretions/secretions of the blowfly Lucilia sericata (Meigen) (Diptera:Calliphoridae) against bacteria. However, the antibacterial activity of its sibling species, Lucilia cuprina (Wiedemann) (Diptera:Calliphoridae) against a wide range of pathogenic bacteria has never been determined. The aim of this study was to develop a new procedure to produce whole body extract of larvae of L. cuprina via methanol extraction as well as to demonstrate the in vitro antibacterial activity of this extract against seven selected wound pathogens (Staphylococcus aureus, methicillin-resistant S. aureus, S. epidermidis, Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli). The turbidimetric assay demonstrated that L. cuprina larval extract was significantly potent against all bacteria tested (P < 0.001). Additionally, colony-forming unit (CFU), agar well diffusion and minimum inhibitory concentration assays have confirmed the apparent potency of larval extract against P. aeruginosa. The reconstituted larval extract was highly robust and thermally stable. These observations substantiated the feasibility of the methanol extraction method in the production of larval extract.

Secondary prevention of osteoporotic fractures--an "OPTIMAL" model of care from Singapore

A significant care gap exists in the management of osteoporotic fractures. Osteoporosis Patient Targeted and Integrated Management for Active Living (OPTIMAL) is a secondary fracture prevention program instituted in the public hospitals of Singapore. We aim to describe the operational characteristics of OPTIMAL and initial audit data of patients who were recruited into the program at Singapore General Hospital.

INTRODUCTION

Fractures often represent the first opportunity for care of osteoporosis. However, a significant care gap still exists in the management of these sentinel events and underdiagnosis and undertreatment of osteoporotic fractures are prevalent worldwide. Fracture liaison services run by care coordinators have been shown to reduce the fracture care gap. OPTIMAL is a clinician champion-driven, case manager-run secondary fracture prevention program set up in the public hospitals of Singapore in 2008.

METHODS

We present the operational characteristics and initial audit data of OPTIMAL from the largest tertiary teaching hospital in Singapore.

RESULTS

One thousand and fourteen patients have been recruited into OPTIMAL at our hospital since 2008, and 476 patients are currently in active follow-up. Two hundred and eighty-seven patients had completed a 2-year follow-up at the hospital as of August 2012 and were evaluated; 97.5% of these patients had DXA evaluation upon enrollment into the program, and 62% of the patients reported compliance with an exercise program over the 2-year follow-up. Compliance to osteoporosis medications as estimated by the medication possession ratio (MPR) was 72.8 ± 34.5% at 2 years with patients maintaining good compliance (MPR ≥ 80%) for an average of 20.2 months (95% CI 19.3-21.1).

CONCLUSION

Our report provides the first compelling evidence of the potential success of a secondary fracture prevention program from an Asian country. The ultimate success of the program will be determined by fracture outcomes and cost effectiveness, but in the interim, clear evidence of enhanced assessment and treatment rates has been demonstrated.

A double-blind, placebo-controlled, randomized, multicenter study to investigate CHInese Medicine Neuroaid Efficacy on Stroke recovery (CHIMES Study)

Rationale Traditional Chinese Medications(TCM) have been reported to have beneficial effects in stroke patients, but were not rigorously evaluated by GCP standards. Aim This study tests the hypothesis that Neuroaid, a TCM widely used in China post-stroke, is superior to placebo in reducing neurological deficit and improving functional outcome in patients with acute cerebral infarction of an intermediate severity. Design This is a multicenter, randomised, double-blind, placebo-controlled study of Neuroaid in ischemic stroke patients with National Institute of Health Stroke Scale(NIHSS) 6-14 treated within 48 h of stroke onset. Neuroaid or placebo is taken (4 capsules) 3 times daily for 3 months. Treatments are assigned using block randomization, stratified for centers, via a central web-randomization system. With a power of 90% and two-sided test of 5% type I error, a sample size is 874. Allowing for a drop-out rate of up to 20%, 1100 individuals should be enrolled in this study. Study Outcomes The primary efficacy endpoint is the modified Rankin Scale(mRS) grades at 3 months. Secondary efficacy endpoints are the NIHSS score at 3 months; difference of NIHSS scores between baseline and 10 days, and between baseline and 3 months; difference of NIHSS sub-scores between baseline and 10 days, and between baseline and 3 months; mRS at 10 days, 1 month, and 3 months; Barthel index at 3 months; Mini Mental State Examination at 10 days and 3 months. Safety outcomes include complete blood count, renal and liver panels, and electrocardiogram.

STUDY REGISTRATION

ClinicalTrials.gov identifier: NCT00554723.

The value of bilateral ipsilateral and contralateral motor evoked potential monitoring in scoliosis surgery

Intraoperative monitoring (IOM) of the motor pathways is a routine procedure for ensuring integrity of corticospinal tracts during scoliosis surgery. We have previously demonstrated presence of ipsilateral motor evoked potentials (MEPs) during IOM for scoliosis surgery, but its significance was uncertain. In this case series, we show concurrent ipsilateral and contralateral MEP amplitude changes obtained with cortical stimulation are of value in reducing false positive observations during IOM. The use of this easily recordable MEP is thus advocated as a diagnostic adjunct to contralateral MEPs for scoliosis and spinal surgery.

Congenital osteofibrous dysplasia associated with pseudoarthrosis of the tibia and fibula

The association between congenital pseudoarthrosis and osteofibrous dysplasia of the tibia and fibula is a rare entity that has been recently recognized. We report a male newborn who was found to have swelling and deformity of the left lower leg. Radiographs and magnetic resonance imaging showed an extensive destructive lesion of the tibial shaft, with dysplastic congenital pseudoarthrosis of the lower fibula. Histopathological examination confirmed the diagnosis of congenital pseudoarthrosis of the tibia and fibula with underlying osteofibrous dysplasia involving both bones. Immunohistochemical stains showed cytokeratin positivity.

Traction and spica casting for closed femoral shaft fractures in children

PURPOSE

To evaluate the treatment outcome of skin traction followed by spica casting for closed femoral shaft fractures in children.

METHODS

Between September 1997 and December 2001 inclusive, outcomes of 63 children aged one month to 15 (mean, 5.3) years with closed femoral shaft fractures managed with skin traction and spica casting were reviewed. Depending on age, patients were kept in traction from 2 to 15 (median, 9) days, then in spica casts for 2 to 8 (median, 5) weeks.

RESULTS

Bony union took 3 to 12 (median, 6) weeks. There were no malunion, nonunion, or rotational deformities. Nor were there any significant limb length discrepancies, pressure sores, or nerve palsies. On no occasion was a spica cast removed and reapplied for loss of fracture reduction. At final follow-up, limb length discrepancy was noted in 14 (22%) of the patients, but none had a discrepancy of greater than 1.5 cm or a short-legged gait.

CONCLUSION

Skin traction followed by spica casting for closed femoral shaft fractures in children is safe, cost-effective and associated with a low complication rate. It is effective in children below 5 years of age and no less effective in older children, except in instances of open fracture, multiple fractures, or older children with large statures, which conditions render them intolerant to spica casts.

Cutaneous silent periods in the evaluation of cord compression in cervical spondylosis

OBJECTIVE

The clinical diagnosis of cervical spondylotic myelopathy (CSM) may be challenging in patients with cervical spondylosis (CS). Routine nerve conduction studies (NCS) may not evaluate cord compression adequately.

METHODS

We obtained cutaneous silent periods (CSP) in 26 consecutive patients presenting with clinical features of CS, in comparison with 30 normal controls. The results were also compared with transcranial magnetic stimulation (TMS) findings, and magnetic resonance imaging of the cervical cord as the gold standard.

RESULTS

CSP findings showed similarly high sensitivity of up to 96% with TMS in evaluating cervical cord dysfunction.

CONCLUSION

In specific clinical settings, CSP is of value for the diagnosis of CSM in CS. CSP measurement is advocated as a simple and rapid diagnostic adjunct to NCS in evaluating CS patients with possible cord compromise.

Biometrical aspects of drug development

Once the activity of a compound has been established in the laboratory (usually by use of experimental animals) the next stage of development is to bring this forward to humans in early-phase clinical trials. A pharmacokinetic study aims to establish an effective dosing regimen for the compound in order to reach concentrations within the therapeutic window as quickly as possible. The aim of the phase I trials is typically to determine a maximal safe dose with which more rigorous investigation of activity in a phase II trial can be conducted. This chapter deals with statistical issues related to the design of phase I studies.

Intraoperative monitoring study of ipsilateral motor evoked potentials in scoliosis surgery

Ipsilateral motor evoked potentials (MEPs) in spinal cord surgery intraoperative monitoring is not well studied. We show that ipsilateral MEPs have significantly larger amplitudes and were elicited with lower stimulation intensities than contralateral MEPs. The possible underlying mechanisms are discussed based on current knowledge of corticospinal pathways. Ipsilateral MEPs may provide additional information on the integrity of descending motor tracts during spinal surgery monitoring.

Transcranial magnetic stimulation screening for cord compression in cervical spondylosis

OBJECTIVE

Cervical spondylosis (CS) often results in various degrees of cord compression, which can be evaluated functionally with transcranial magnetic stimulation (TMS). We investigate the use of TMS as a screening tool for myelopathy in CS.

METHODS

We prospectively studied 231 patients classified into Groups 1 to 4 based on MRI grading of severity of cord compromise. TMS elicited central motor conduction times and motor evoked potential (MEP) amplitudes in all 4 limbs. The results were compared with those from 45 healthy controls.

RESULTS

TMS showed 98% sensitivity and 98% specificity for cord abnormality using MRI as reference standard.

CONCLUSIONS

MEP abnormalities are useful for electrophysiological evaluation of cord compression in CS. While TMS is not a substitute for MRI, it is of value as a rapid, inexpensive and non-invasive technique for screening patients before MRI studies.

p53 and bcl-2 expression in invasive and pre-invasive uterine papillary serous carcinoma and atrophic endometrium

INTRODUCTION

Uterine papillary serous carcinoma (UPSC), a high-grade tumour, is known to be associated in some cases with an identifiable intraepithelial neoplasia (IEN) component. Biomarker studies incorporating this latter component are not well documented. One aim of the present study was to compare levels of immunohistochemical (IHC) expression of p53 tumour suppressor gene and bcl-2 oncoprotein between UPSC and IEN, as well as normal endometrium to determine its biologic significance. The other major aim was to determine if these IHC results have any bearing on survival data in this tumour.

MATERIALS AND METHODS

An immunoreactivity score was assigned for examination of p53 and bcl-2 expression in a total of 21 cases of UPSC, 9 with an evaluable IEN component and 11 with associated non-neoplastic endometrium. Statistical analysis of IHC results was performed, in addition to correlation with survival data and disease stage.

RESULTS

p53 was identified in 16/21 cases of UPSC (76%) and 8/9 cases of IEN (89%), and no cases of normal endometrium. By contrast, bcl-2 was positive in all normal endometria with less expression in UPSC leaving 15/21 (71%) cases positive, and in IEN, leaving 5/9 (55%) of cases positive. Differences in immunoreactive scores for both p53 and bcl-2 between UPSC and benign glands, as well as between IEN and benign glands reached statistical significance with P values of 0.006 and 0.014 for p53, and 0.003 and 0.027 for bcl-2 respectively. There was no statistical significance between values for UPSC and IEN. Cox regression analysis found no statistically significant relationship between patient survival time in early and late stages of disease, and p53 and bcl-2 immunoscores.

CONCLUSIONS

The lack of a significant difference between the bcl-2 and p53 values for both UPSC and IEN suggests that these molecular alterations occur at an early stage of tumour pathogenesis. A potential advantage of the use of immunohistochemical markers is their application to routinely processed surgical specimens. In this case, bcl-2 and p53 were applied in UPSC to determine any potential significance, but neither marker proved to be a useful predictor of survival time or disease stage.

Pectoralis major motor evoked potentials in cervical spondylosis

Myelopathy is a severe complication of cervical spondylosis (CS). We studied 27 consecutive patients with CS referred for evaluation for possible myelopathy using transcranial magnetic stimulation. The findings were compared with those from 20 normal controls. Magnetic resonance imaging was utilized to assess the degree of cord compromise. Central motor conduction time (CMCT) abnormalities showed equivalent diagnostic yield with pectoralis major (PM) recordings, as compared with combined first dorsal interossei and abductor hallucis recordings. Our findings show that CMCT measurement with PM recordings is of value as a diagnostic adjunct in the electrophysiological evaluation of myelopathy in CS.

Candida spondylodiscitis and epidural abscess: management with shorter courses of anti-fungal therapy in combination with surgical debridement

Epidural abscess associated with candidal spondylodiscitis is rarely seen, particularly when it involves the cervical and thoracic spine. We report two such cases that were successfully managed with early surgical debridement, as well as medical therapy with intravenous amphotericin followed by oral fluconazole. The literature related to candidal spinal infection is reviewed, and a rational approach to the management of this uncommon condition is proposed. A good outcome may generally be expected with early diagnosis as well as appropriate surgical and pharmacological treatment. Oral fluconazole appears to be useful in the management of candida spondylodiscitis complicated by epidural abscess formation. Treatment until a normal ESR is attained is ideal, and this may be as short as 3 months when surgical drainage has been adequately performed.

Determination of the flight range and dispersal of the house fly, Musca domestica (L.) using mark release recapture technique

In order to control any pest it is essential to study the life cycle, biology and bionomics of the target pest under control. With this respect, we have studied the flight range of the house fly Musca domestica (L.). The flight range of the house fly from two sites i.e, the poultry farm and a stable farm has been studied. The flight range study was conducted using a mark release technique. The approach we used in this study was that the flies collected from the respective farms were marked and released at different distances from the farms. The flies were then re-captured from the poultry farm and the stable farm. Studies conducted elsewhere use the technique of releasing the insect species at one spot and recapturing the insect species with the help of baited traps placed at various locations from the release point. The advantage of the approach used in this study was that the flight range as well as the homing effect was determined. From this study, the flight range of house flies released at the poultry farm was 7 km whereas flight range for flies release from stable farm was 5 km. The recovery rate of house flies at the poultry and stable farm was 0.05% and 0.016%, In this study, marked specimens has been detected up to 8 days in field conditions indicating that under field condition the life expectancy could be in the range of 1-2 weeks.

Risk perception is affected by modes of risk presentation among Singaporeans

INTRODUCTION

Not much is known about how Singaporeans perceive and react to risk presentation. There is no consensus on whether the European Union guidelines for describing the risk of side effects are valid. This study investigated the effect of different modes of risk presentation on how Singaporeans perceive and react to medical risk. Furthermore, we investigated the practical usage of qualitative phrases, the European Union's adjectives in particular, in describing levels of risk.

MATERIALS AND METHODS

A hypothetical situation about the risk of side effects of an influenza vaccine was presented in either a probability format (i.e., 5%; n = 42) or a frequency format (i.e., 1 out of 20; n = 43). The 2 versions of questionnaire were handed out in an alternate order to a convenience sample of 47 healthcare professionals and 38 university students.

RESULTS

Respondents presented with a "5% risk" were more likely to describe the risk as "uncommon" or "rare", as compared to respondents presented with a risk of "one out of twenty" (P <0.01). Furthermore, the former showed more willingness to accept the influenza vaccine described in the hypothetical situation than in the latter, but this was not statistically different (67% versus 54%; P >0.1).

CONCLUSIONS

Modes of risk presentation affect how people perceive risk, even among people who are highly educated.

Nonrandom intragenic variations in patterns of codon bias implicate a sequential interplay between transitional genetic drift and functional amino acid selection

Although most codon third bases appear to be functionless, the synonymous codons so defined exhibit a strikingly nonrandom distribution (codon bias) within human and other genes. To examine this phenomenon further, we generated a database of DNA sequences encoding human transmembrane cell-surface receptor proteins. Using this database we show here that the guanine and cytosine content of codon third bases (GC3) varies intragenically with the nature of the specified receptor domains (transmembrane > extracellular > intracellular domains; p < 0.001), the phenotype of the encoded amino acids (hydrophobic > hydrophilic > neutral amino acids; p < 0.001), and the receptor affiliation of the transmembrane (G-protein-coupled receptors > receptor tyrosine kinases; p < 0.001). Within gene regions specifying transmembrane domains, GC3 declines as domain functionality becomes redundant with increasing hydrophobicity (p < 0.001). Codons containing the second-base cytosine (XCZ, which encodes neutral amino acids) are selectively depleted of third-base adenine content (A3: XCA codons) when encoding transmembrane domain residues, consistent with positive selection for transitional mutation of XCG to XTG (which encodes hydrophobic amino acids) rather than to the synonymous XCA. Supporting this XCG --> XTG mechanism of codon bias, the G3:A3 ratio of codons specifying the transmembrane amino acid glycine (GGZ) is intermediate between that of its functional homolog alanine (GCZ) and that of hydrophobic valine (GTZ), even though the C3:T3 ratios are similar. Conversely, nearest-neighbor analysis of third bases 5' to codons specifying valine and leucine (CTZ) confirms a significant difference in C3:T3 but not G3:A3 ratios (i.e., C3/G1 --> T3/G1 > C3/A1; p < 0.001), consistent with the functionally advantageous retention of hydrophobic residues. These data raise the possibility that patterns of intragenic codon bias reflect a balance between negative and positive selection, suggesting in turn that analysis of codon third-base usage may help to predict the functional significance of encoded products.

Systematic correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy

STUDY DESIGN

A prospective study over a 3.5-year period involving transcranial magnetic stimulation and magnetic resonance imaging.

OBJECTIVES

To assess the correlation of transcranial magnetic stimulation and magnetic resonance imaging in cervical spondylotic myelopathy qualitatively and statistically.

SUMMARY OF BACKGROUND DATA

Cervical spondylotic myelopathy presents with different degrees of cord compression, which can be assessed by magnetic resonance imaging. There are no large studies correlating transcranial magnetic stimulation and magnetic resonance imaging findings in this condition.

METHODS

A total of 141 patients with a clinical diagnosis of cervical spondylotic myelopathy were prospectively studied over a 3.5-year period. They were classified into Groups 1 to 4 based on severity of cervical cord changes on magnetic resonance imaging. All had transcranial magnetic stimulation and central motor conduction time measurements within 2 months of the magnetic resonance imaging study.

RESULTS

Twenty-eight, 49, 28, and 36 patients were classified into Groups 1 to 4, respectively. Mean upper limb and lower limb central motor conduction times correlated with the severity of magnetic resonance cord compression. The absence of central motor conduction time abnormalities correlated reliably with the absence of cervical cord impingement as in Group 1. Statistically significant right left difference in central motor conduction time in the lower limbs was seen between Groups 1 (no cord changes) and Group 2 (mild cord impingement). Eight other patients with diagnoses other than cervical spondylotic myelopathy all showed central motor conduction time abnormalities. The sensitivity and specificity for transcranial magnetic stimulation for differentiating the presence from absence of magnetic resonance imaging cord abnormality were 100% and 84.8%, respectively.

CONCLUSIONS

Transcranial magnetic stimulation showed excellent correlation with magnetic resonance imaging findings and can be considered as an effective technique for screening patients for cervical cord abnormalities before magnetic resonance imaging in the clinical setting. The findings in this study have relevant implications in the pathophysiology, management, and health costs of cervical spondylotic myelopathy.

Intra-operative monitoring in scoliosis surgery with multi-pulse cortical stimuli and desflurane anesthesia

STUDY DESIGN

Prospective, observational study.

SETTING

Country General Hospital, Singapore.

OBJECTIVE

Intraoperative monitoring (IOM) with motor-evoked potentials (MEPs) assesses the integrity of cortical spinal tracts during scoliosis surgery. MEPs are sensitive to the effects of inhalational anesthetic agents. We evaluate the use of desflurane in combination with multipulse cortical stimulation in this study.

METHODS

In all, 10 consecutive neurologically normal subjects underwent scoliosis surgery with desflurane anesthesia (0.5 maximum alveolar concentration) and five pulse cortical stimulation (250 Hz) from two stimulators in parallel configuration, delivering a maximum intensity of 160 mA.

RESULTS

Consistent MEPs were obtained from the abductor hallucis and tibialis anterior in nine of ten and five of five of subjects, respectively. Baseline coefficients of variations were below 16% for both muscles.

CONCLUSION

This combination of anesthetic and stimulation protocols is efficacious for IOM during spinal cord surgery. Our findings support the use of desflurane for successful acquisition of MEPs during scoliois surgery as an alternative anesthetic regime.

Measuring quality of life in Chinese cancer patients: a new version of the Functional Living Index for Cancer (Chinese)

INTRODUCTION

Since its translation into Chinese, the Functional Living Index for Cancer (FLIC) has not been widely received due to some of its difficulties. We modified its visual analogue scale (VAS) to an ordered categorical scale and changed some of the wording in the instrument. This study examined the measurement properties of the modified FLIC.

MATERIALS AND METHODS

The modified version of FLIC and the Functional Assessment of Cancer Therapy (FACT-G Chinese version 4) were filled in by 140 patients recruited from the National Cancer Centre Singapore. The patients' FLIC scores were compared with their clinical characteristics to establish known-group validity. Convergent and divergent validity of FLIC were examined by correlation analysis with FACT-G and its sub-scales. Cronbach's alpha and relative efficiency were also examined.

RESULTS

FLIC and most of its sub-scales could indicate a clear and statistically significant difference of quality of life (QOL) according to patients' performance status and treatment status. FLIC strongly correlated with FACT-G. The Physical, Psychological, and Symptoms sub-scales of FLIC converged to and diverged from FACT-G sub-scales as conceptually expected. Cronbach's alpha indicated a satisfactory level of reliability. FLIC appeared to be more efficient than FACT-G, meaning that a smaller sample size will be required for FLIC than for FACT-G to achieve the same research purpose.

CONCLUSIONS

The modified version of FLIC was found to have achieved satisfactory measurement properties. This is a user-friendly alternative to the original FLIC.

Advances in surgical treatment of osteoporotic fractures of the spine

INTRODUCTION

To highlight recent advances in the management of osteoporotic compression fractures of the spine.

METHODS

A MEDLINE search was conducted from January 1975 to October 2001. Keywords included osteoporotic compression fractures, osteoporosis and spine fractures.

RESULTS

Osteoporotic fractures of the spine often cause significant morbidity to the elderly individual. Diagnosis requires a detailed history and physical examination and investigations are usually required to exclude other causes of back pain. Magnetic resonance imaging (MRI) is often helpful in excluding other causes of pathologic fracture but may not be confirmatory. Conservative treatment was the traditional approach, but newer percutaneous treatments, such as vertebroplasty and kyphoplasty, are safe and simple day surgery procedures which allow for rapid recovery of symptoms and prevention of increasing spinal deformity. Neurological deficit as a result of spinal canal compromise from retropulsed fragments, though relatively uncommon, is well recognised as a cause of significant morbidity and is a major indication for open spinal surgery. Various spinal approaches including anterior or posterior decompression combined with a variety of stabilisation techniques have been reported in the literature. Rehabilitation is often required to improve physical function.

CONCLUSIONS

Osteoporotic fractures of the spine are a common cause of morbidity in the elderly. Patients who have persistent pain despite conservative treatment require investigation to exclude other pathological causes of fracture. Percutaneous vertebroplasty and kyphoplasty are new techniques that offer much promise in the treatment of these elderly patients. Open surgery may still be required where there is significant neurologic compromise.

Susceptibility of Culex sitiens to Japanese encephalitis virus in peninsular Malaysia

The susceptibility of Culex sitiens to Japanese Encephalitis (JE) virus was examined in the laboratory. Cx. sitiens became infected with JE virus on day 8 and subsequently it is able to transmit the virus when it takes a blood meal. Both parts of the experiment were carried out using artificial membrane feeding technique.

Agreement or prediction: asking and answering the right question

INTRODUCTION

Measuring agreement and measuring predictive ability are similar but distinct problems. Failure to appreciate the conceptual and practical differences may lead clinical researchers to give the right answer to the wrong question.

METHODS

We illustrate the relation and difference between measuring agreement and predictive ability in a non-technical way. We provide a real example investigating the feasibility of using preoperative breast cancer tumour size measurements to estimate postoperative histological size. The intraclass correlation and R-squared are calculated to ascertain the level of agreement and predictive ability respectively.

RESULTS

Analysis of agreement and analysis of predictive ability serve different purposes. The optimal solution found in terms of agreement may be different from that found for prediction.

CONCLUSIONS

A careful clarification of the goal of an investigation is important. Using an inappropriate analysis can lead to misleading results, or to results that do not really answer the research question of interest.

A 16-year-old boy with back pain

This case is presented to illustrate the imaging and clinical findings of a condition of interest to orthopaedic surgeons. The initial findings are noted on this page. The clinical and imaging diagnoses are presented on the following pages.

The need for collaboration between clinicians and statisticians: some experience and examples

INTRODUCTION

Very often we see poor communication and collaboration between clinicians and statisticians. Both sides may fail to realise the importance of a truly collaborative effort. In this paper we give examples to illustrate some problems clinicians and statisticians may encounter when they do not have the full support of each other. The aim is to convince both parties the importance of a truly collaborative effort.

METHODS

Real examples in various medical research areas are drawn from the authors' practical experience for illustration. The examples cover various research aspects such as the use of computer software, regression analysis and interpretation of findings.

RESULTS

Superficial collaboration between clinicians and statisticians may lead to serious problems and sub-optimal research practice that may not be obvious in the first sight. Some of the barriers to effective communication and collaboration are discussed.

CONCLUSIONS

On the one hand, robust statistical practice is vital in many medical research projects. On the other hand, medical thinking is important in the formulation and application of statistical strategies. Statistical inputs should be integrated into medical research projects throughout the whole research process. Sporadic contacts between clinicians and statisticians are not enough. Both parties must learn to communicate more effectively and to be willing to collaborate with each other.

The Torg--Pavlov ratio in cervical spondylotic myelopathy: a comparative study between patients with cervical spondylotic myelopathy and a nonspondylotic, nonmyelopathic population

STUDY DESIGN

A radiologic study to compare the Torg--Pavlov ratios between patients with cervical spondylotic myelopathy and a nonspondylotic, nonmyelopathic population.

OBJECTIVES

To determine and compare the Torg--Pavlov ratios between the two groups of patients.

SUMMARY OF BACKGROUND DATA

Patients with congenital cervical spinal canal stenosis are more likely to develop cervical spondylotic myelopathy. The Torg--Pavlov ratio eliminates errors related to magnification, a problem with determination of spinal canal stenosis from direct measurements of plain cervical spine radiographs. There has only been one other study that directly compares the Torg--Pavlov ratio between patients with cervical spondylotic myelopathy and a normal control population.

METHODS

The preoperative plain lateral cervical spine radiographs of 28 patients with cervical spondylotic myelopathy requiring surgical decompression were compared with radiographs of 88 nonspondylotic, nonmyelopathic patients. The Torg--Pavlov ratio was computed for each level from C3 to C7.

RESULTS

The study showed that the Torg--Pavlov ratio is significantly smaller (P < 0.001) in myelopathic patients (mean 0.72 +/- 0.08) compared with the control patients (mean 0.95 +/- 0.14). This was so when individual levels and the mean values were compared. Age was also found to be a significant factor (P = 0.002), although lesser in magnitude when compared with the Torg--Pavlov ratio (P = 0.0001).

CONCLUSIONS

The Torg--Pavlov ratio is significantly lower in patients with cervical spondylotic myelopathy compared with a nonspondylotic, nonmyelopathic population. It could possibly be used to predict the likelihood of developing cervical spondylotic myelopathy.

Introduction to Bayesian methods for medical research

Bayesian statistical methods provide a credible alternative to traditional statistical approaches used in medical research. In this article, the author gives a brief introduction to the key concepts involved in Bayesian methods and compares them with some commonly used non-Bayesian statistical techniques.

Results of cervical laminoplasty and a comparison between single and double trap-door techniques

Thirty-seven patients were studied for an average of 32.1 months after canal-expansive laminoplasty for the treatment of multiple-level cervical stenosis caused by spondylosis, ossification of posterior longitudinal ligament, prolapsed intervertebral disc, and other conditions. Short-term and medium-term results were recorded clinically, using the scoring system proposed by the Japanese Orthopedic Association. The canal expansion was also recorded with radiological studies. The improvement rate was good to excellent in 58.3% of the patients. Postoperative neurological deterioration occurred in only four patients. Poorer results were observed in female patients and in those in whom surgery was delayed. Surgery within 12 months of onset of symptoms gave good results. Serious complications occurred in only two patients. There were 12 patients who were treated with the single trap-door (unilateral) laminoplasty and 25 patients treated with the double trap-door (sagittal splitting of the spinous processes) laminoplasty; their results were compared. There was no significant difference in neurological outcome between the two methods.

Endurance training of the trunk extensor muscles in people with subacute low back pain

BACKGROUND AND PURPOSE

Clinicians treating patients with low back pain often use exercise to reduce pain and improve function. The aim of this study was to evaluate the effectiveness of trunk extensor endurance training in reducing pain and decreasing disability in subjects with subacute low back pain (ie, onset of back pain within 7 days to 7 weeks).

SUBJECTS AND METHODS

Patients were randomly assigned to either an experimental group or a control group. A visual analog scale and the pain rating index (PRI) of the McGill Pain Questionnaire (MPQ) were used to obtain baseline measurements of pain. The Roland Morris Disability Questionnaire (RMDQ) was used to measure disability, and the Sorensen Test was used to measure trunk extensor endurance. Subjects in the experimental group attended exercise sessions 3 times a week for 6 weeks. Subjects in the control group did not do exercises. Both groups were given back care advice and hot packs for 15 minutes, 3 to 5 times per week. Reassessments were carried out at 3 and 6 weeks.

RESULTS

There were differences between the 2 groups at 3 weeks in regard to pain intensity during the evaluation session and pain experienced over the preceding 24 hours, the total MPQ PRI, the sensory component of the MPQ PRI, and the RMDQ. At 6 weeks, no differences were found for pain measurements, disability scores, and holding time on the Sorensen Test.

CONCLUSION AND DISCUSSION

Trunk extensor endurance training reduced pain and improved function at 3 weeks but resulted in no improvement at 6 weeks when compared with the control group. Endurance exercise is considered to expedite the recovery process for patients with an acute episode of low back pain.

Exploratory thoughts on clinical trials with utilities

We consider problems of choice of sample size and allocation in the clinical trials context when utilities are explicitly taken into account. In particular, we consider utilities of benefits and side-effects (and their trade-offs), as well as utility functions that trade-off scientific and ethical concerns.

Vascular assessment in the neuropathic diabetic foot

Diabetic foot infections, a common source of morbidity and mortality, often have been related to vasculopathy and neuropathy in its etiopathogenesis, especially in the elderly person with diabetes. However, blood flow in the neuropathic diabetic foot has not been evaluated extensively, and there is evidence of abnormal blood flow patterns in the neuropathic diabetic foot unrelated to ischemia. The authors studied young persons with diabetes, with varying degrees of neuropathy, to assess the extent of vasculopathy in their lower limbs. Twelve young persons with insulin-dependent (Type I) diabetes (mean age, 36.1 +/- 1.975 years) and peripheral neuropathy, all of whom had previous surgery for diabetic foot infections, were identified. Confirmatory evidence of neuropathy was made using electromyographic studies and clinical tests that showed severe peripheral neuropathy. The results of vascular assessment of both lower limbs did not reveal any change in the pulse wave velocities from the popliteal to the digital vessels of the big toe as compared with correspondingly matched controls. There also was no significant stenosis in any of the vessels studied as far as the level of the dorsalis pedis and posterior tibial vessels. The normal triphasic pattern of arterial blood flow was lost. A monophasic pattern was present in all patients with prolonged diastolic flow at the level of the dorsalis pedis and posterior tibial arteries and distally. The pulsatility index was 3.14 +/- 0.81 as compared with 9.85 +/- 4.2. Mean toe pressures in the patient with diabetes was 64.17 +/- 20.87 mm Hg as compared with 98.23 +/- 10.12 mm Hg in controls. A linear correlation of decreasing toe pressures with increasing severity of neuropathy was seen (R = 0.7). The data suggest that changes exist in the blood flow patterns in young patients with diabetes and neuropathy, even in the absence of lower limb ischemia.

Effect of operative position on sagittal alignment of the lumbar spine

A variety of techniques and frames are used for positioning patients during posterior lumbar spinal instrumentation and fusion. Little information is available on the relationship of lumbar lordosis and the various positioning options, so it was felt that further investigation was warranted. Ten volunteers with no history of back pain were positioned and radiographed in the standing position followed by four lateral radiographs with the patient positioned on chest rolls, Andrew's frame, the Hasting's frame, and a four-poster spinal frame. Total lumbar lordosis from L1 to S1 as well as intervertebral body angles at each of the lumbar interspaces using standardized techniques were computed. No significant difference was found in lumbar lordosis between the standing and chest roll position. However, there was approximately a 50% reduction in lumbar lordosis when using the Hasting's, Andrew's, and four-poster frame as compared to the standing and chest roll configuration. The clinical implications are discussed.

The limitations of magnetic resonance imaging in the diagnosis of pathologic vertebral fractures

Magnetic resonance imaging has been increasingly used in recent years to screen patients with suspected spinal metastases. The authors present four cases, all of whom were elderly patients with vertebral compression fractures, who were diagnosed with magnetic resonance imaging to have probable neoplastic involvement. In each case, vertebral body biopsies indicated a benign pathology. The authors discuss the diagnostic criteria of magnetic resonance imaging of spinal metastases and the limitations of magnetic resonance imaging in the diagnosis of pathologic vertebral fractures.

Effects of social disincentive policies on fertility behavior in Singapore

Five social disincentive policies were implemented by the Singapore government in 1973 to augment its fertility reduction program. The policies involve increasing delivery charges in government hospitals, school admission priority for children, maternity leave, priority in allocation of government housing, and income tax relief. In a two-year prospective study, 1,010 married abortees (study group) and 943 married parturients (comparison group) were questioned to determine their awareness and understanding of these policies, and whether the policies influenced their decision concerning their present pregnancies or would influence future decisions. Except for the tax policy, these disincentives were known to a fairly large proportion of the women studied. Knowledge was positively related to education level. Four of the five disincentives have, to varying degrees, influenced the women's decisions concerning their present pregnancies and may do so in future pregnancies. The two most widely known and most influential disincentives are those affecting school admission priority and accouchement fees.