Original Article

Feng YP, Ke X, Zhai M, Xin Q, Gong YQ, Liu QJ
Correspondence: Dr Qiji Liu, liuqiji@sdu.edu.cn

ABSTRACT
Introduction Hereditary spastic paraplegia (HSP) belongs to a large, heterogeneous group of progressive neurodegenerative diseases characterised by progressive lower extremity weakness and spasticity, which is caused by developmental failure or degeneration of motor axons in the corticospinal tract. Classical genetic studies have identified at least 46 genetic loci responsible for HSP.
Methods A genetic study was conducted on a four-generation Chinese family with autosomal dominant HSP. The SPAST gene was investigated using linkage analysis and direct sequencing. Findings were compared with unaffected family members and 50 normal, unaffected individuals who were matched for geographical ancestry.
Results We identified a novel 14-bp heterozygous deletion that induced a frameshift mutation in exon 15 of SPAST (SPG4). This mutation is predicted to have functional impact and found to cosegregate with the disease phenotype.
Conclusion Our results have expanded the mutation spectrum of the SPAST gene. These findings could help clinicians provide prenatal diagnosis of affected foetuses in families with a known history of such neurodegenerative diseases.

Keywords:  hereditary spastic paraplegia, mutation, spastin, SPG4
Singapore Med J 2013; 54(5): 251-254; http://dx.doi.org/10.11622/smedj.2013102

REFERENCES

Tan WS, Tang CL, Koo WH
Correspondence: A/Prof Choong Leong Tang, tang.choong.leong@sgh.com.sg

ABSTRACT
Introduction The use of faecal immunochemical occult blood test (FIT) has been reported to decrease mortality  from colorectal cancer. The Singapore Cancer Society (SCS) gives out FIT kits to encourage opportunistic screening of colorectal cancer. Any Singapore citizen or permanent resident aged ≥ 50 years is eligible to receive two FIT kits. Participants with at least one positive FIT are referred for further evaluation. We aimed to analyse the results of SCS data from the year 2008.
Methods The factors evaluated included compliance, positive test rate (PR) and positive predictive value (PPV) of FIT. 
Results 20,989 participants received 41,978 kits in 2008. Compliance was 38.9%, with 8,156 participants returning at least one kit. 8% of participants tested positive, and 75% of these test-positive participants agreed to undergo further investigations. 33 participants had colorectal cancers, 45 had advanced polyps (≥ 1 cm) and 90 had polyps < 1 cm. Histologically, 114 polyps were adenomatous, 20 were hyperplastic and 1 was serrated. PPV of colorectal neoplasia for those who underwent further colonoscopy was 34%. Over half of the participants who had only one positive test had colorectal neoplasia.
Conclusion PR and PPV of FIT in our study were comparable to that in the literature. However, compliance was low and a quarter of all participants who tested positive refused further investigations. Extensive population education programmes are required to improve compliance and tackle inhibitions among the masses. It is also important to take steps to enhance the cost effectiveness of future screening programmes.

Keywords:colorectal cancer, faecal occult blood test, screening
Singapore Med J 2013; 54(4): 220-223; http://dx.doi.org/10.11622/smedj.2013077

REFERENCES

Arakawa H, Kaise M, Sumiyama K, Saito S, Suzuki T, Tajiri H
Correspondence: Dr Hiroshi Arakawa, endosc-arakawa@jikei.ac.jp

ABSTRACT
Introduction Pulse oximetry (SpO_²) measures oxygen saturation but not alveolar ventilation. Its failure to detect alveolar hypoventilation during sedated endoscopy under oxygen supplementation has been reported. The aim of this study was to measure the masking effect of oxygen supplementation in SpO₂ when alveolar hypoventilation develops during sedated endoscopy.
Methods A total of 70 patients undergoing sedated diagnostic colonoscopy were randomly divided into two groups – oxygen supplementation group (n = 35) and room air breathing group (n = 35). SpO₂ and end-tidal carbon dioxide (etCO₂) were measured by non-intubated capnography during the procedure for all the patients.
Results The rise of etCO₂ caused by alveolar hypoventilation was comparable in the two groups after sedation. SpO₂ was significantly higher in the oxygen supplementation group than in the room air breathing group (98.6% ± 1.4% vs. 93.1% ± 2.9%; p < 0.001) at peak etCO₂, and oxygen supplementation caused SpO₂ to be overestimated by greater than 5% when compared with room air. SpO2 at peak etCO2 was reduced from the baseline before sedation for the oxygen supplementation and room air breathing groups by 0.5% ± 1.1% and 4.1% ± 3.1%, respectively (p < 0.001).
Conclusion SpO₂ alone is not adequate for monitoring alveolar ventilation during sedated endoscopy under oxygen supplementation due to possible delays in detecting alveolar hypoventilation in patients. Even if SpO₂ decreases by only 1% during the procedure and its level remains near 100%, physicians should consider the onset of severe alveolar hypoventilation, which requires immediate intervention.

Keywords: capnography, endoscopy, hypoventilation, pulse oximetry, sedation
Singapore Med J 2013; 54: 212-215; http://dx.doi.org/10.11622/smedj.2013075

REFERENCES

Ang TL, Kwek AB, Tan SS, Ibrahim S, Fock KM, Teo EK
Correspondence: Adj A/Prof Ang Tiing Leong, tiing_leong_ang@cgh.com.sg

ABSTRACT
Introduction Endoscopic transenteric stenting is the standard treatment for pseudocysts, but it may be inadequate for treating infected collections with solid debris. Surgical necrosectomy results in significant morbidity. Direct endoscopic necrosectomy (DEN), a minimally invasive treatment, may be a viable option. This study examined the efficacy and safety of DEN for the treatment of infected walled-off pancreatic necrosis and infected pseudocysts with solid debris.
Methods This study was a retrospective analysis of data collected from a prospective database of patients who underwent DEN in the presence of infected walled-off pancreatic necrosis or infected pseudocysts with solid debris from April 2007 to October 2011. DEN was performed as a staged procedure. Endoscopic ultrasonography-guided transgastric stenting was performed during the first session for initial drainage and to establish endoscopic access to the infected collection. In the second session, the drainage tract was dilated endoscopically to allow transgastric passage of an endoscope for endoscopic necrosectomy. Outcome data included technical success, clinical success and complication rates.
Results Eight patients with infected walled-off pancreatic necrosis or infected pseudocysts with solid debris (mean size 12.5 cm; range 7.8–17.2 cm) underwent DEN. Underlying aetiologies included severe acute pancreatitis (n = 6) and post-pancreatic surgery (n = 2). DEN was technically successful in all patients. Clinical resolution was achieved in seven patients. One patient with recurrent collection opted for surgery instead of repeat endotherapy. No procedural complications were encountered.
Conclusion DEN is a safe and effective minimally invasive treatment for infected walled-off pancreatic necrosis and infected pseudocysts.

Keywords: debridement, endoscopic drainage, infected pseudocyst, pancreatic necrosis
Singapore Med J 2013; 54: 206-211; http://dx.doi.org/10.11622/smedj.2013074

REFERENCES

Chin CT, Mellstrom C, Chua TS, Matchar DB
Correspondence: Dr Chin Chee Tang, chin.chee.tang@nhcs.com.sg

ABSTRACT
Introduction Ticagrelor is a novel antiplatelet drug developed to reduce atherothrombosis. The PLATO trial compared ticagrelor and aspirin to clopidogrel and aspirin in patients with acute coronary syndromes (ACS). Ticagrelor was found to be superior in the primary composite endpoint of cardiovascular death, myocardial infarction or stroke, without increasing major bleeding events. The current study estimates the lifetime cost-effectiveness of ticagrelor relative to generic clopidogrel from a Singapore public healthcare perspective.
Methods This study used a two-part cost-effectiveness model. The first part was a 12-month decision tree (using PLATO trial data) to estimate the rates of major cardiovascular events, healthcare costs and health-related quality of life. The second part was a Markov model estimating lifetime quality-adjusted survival and costs conditional on events during the initial 12 months. Daily drug costs applied were SGD 1.05 (generic clopidogrel) and SGD 6.00 (ticagrelor). Cost per quality-adjusted life years (QALY) was estimated from a Singapore public healthcare perspective using life tables and short-term costs from Singapore, and long-term costs from South Korea. Deterministic and probabilistic sensitivity analyses were performed.
Results Ticagrelor was associated with a lifetime QALY gain of 0.13, primarily driven by lower mortality. The resulting incremental cost per QALY gained was SGD 10,136.00. Probabilistic sensitivity analysis indicated that ticagrelor had a > 99% probability of being cost-effective, given the lower recommended WHO willingness-to-pay threshold of one GDP/capita per QALY.
Conclusion Based on PLATO trial data, one-year treatment with ticagrelor versus generic clopidogrel in patients with ACS, relative to WHO reference standards, is cost-effective from a Singapore public healthcare perspective.

Keywords: acute coronary syndromes, clopidogrel, cost-effectiveness, Singapore, ticagrelor
Singapore Med J 2013; 54(3): 169-175; doi:10.11622/smedj.2013045

REFERENCES

Gan DE, Dahlui M
Correspondence: Dr Maznah Dahlui, maznahd@ummc.edu.my

ABSTRACT
Introduction Cervical cancer is the third most common cancer among Malaysian women. However, the uptake of cervical cancer screening – Pap smear – by women in Malaysia has been low and remains a challenge. This study was conducted to assess the cervical screening practices of rural women in Malaysia and to examine the factors associated with such practices.
Methods A cross-sectional survey was conducted in five rural districts in Perak, Malaysia. 1,000 households were selected through multistage random sampling. Women aged 20–64 years were interviewed by trained enumerators using structured questionnaires. Binomial logistic regression was used to identify predictors of cervical screening through univariate and multivariate analyses.
Results Among the 959 respondents, only 48.9% had undergone Pap smear at least once in the past three years. Women in the age group 40–49 years (odds ratio 3.027, 95% confidence interval 1.546–5.925; p < 0.005) were found to be significantly more likely to attend cervical cancer screening as compared to those in the age group 20–29 years. Other significant predictors were being married with children, having knowledge of cervical cancer symptoms, receiving relevant information regarding cervical cancer from health personnel or campaigns, being engaged in family planning and receiving encouragement from husbands.
Conclusion Efforts to boost the uptake of Pap smear screening among the rural population should be targeted toward the predictors of positive uptake.

Keywords: cervical screening practices, Pap smear, predictors
Singapore Med J 2013; 54(3): 163-168; doi:10.11622/smedj.2013047

REFERENCES

Wee WW, Wong HF, Lee LC, Han HC
Correspondence: Dr Wee Wei-Wei, wcube@hotmail.com

ABSTRACT
Introduction We aimed to evaluate the local incidences of hydronephrosis and renal impairment in the presence of severe uterovaginal or vault prolapse, and determine whether treatment by surgery or ring pessary resulted in the resolution of hydronephrosis in these patients.
Methods This was a retrospective case study of 121 patients who presented with severe uterovaginal or vault prolapse. All patients who had fourth degree uterovaginal or vault prolapse, and underwent renal ultrasonography and renal function blood tests were included in the study. Follow-up imaging for hydronephrosis was performed to determine the outcome after patients received treatment.
Results The mean age of the study population was 66.1 years. The overall incidence of hydronephrosis was 20.6%. The incidence of hydronephrosis in patients with severe vault prolapse was 7.1%, while that in patients with severe uterovaginal prolapse was 22.4%. Of the 25 patients with hydronephrosis, 16 (64.0%) had complete resolution of hydronephrosis after treatment, 5 (20.0%) had residual but smaller degrees of hydronephrosis, and 4 (16.0%) were lost to follow-up. The incidence of renal impairment was 3.3%.
Conclusion The local incidence of hydronephrosis in patients with severe uterovaginal or vault prolapse was 20.6% in our study. We established that 3.3% of women with severe uterovaginal or vault prolapse had mild renal impairment. Treatment by vaginal surgery for severe uterovaginal or vault prolapse appears to result in either complete resolution or improvement of hydronephrosis in the majority of patients.

Keywords: hydronephrosis, incidence, prolapse, uterovaginal, vault
Singapore Med J 2013; 54(3): 160-162; doi:10.11622/smedj.2013048

REFERENCES

Sharma NA, Garud RS
Correspondence: Dr Namita Sharma, drnamitaalok@gmail.com

ABSTRACT
Introduction Accurate localisation of the greater palatine foramen (GPF) is imperative while negotiating the greater palatine canal for blocking the maxillary nerve within the pterygopalatine fossa. The aim of this study was to define the position of the foramen relative to readily identifiable intraoral reference points in order to help clinicians judge the position of the GPF in a consistently reliable manner.
Methods The GPF was studied in 100 dried, adult, unsexed skulls from the state of Maharashtra in western India. Measurements were made using a vernier calliper.
Results The mean distances of the GPF from the midline maxillary suture, incisive fossa, posterior palatal border and pterygoid hamulus were 14.49 mm, 35.50 mm, 3.40 mm and 11.78 mm, respectively. The foramen was opposite the third maxillary molar in 73.38% of skulls, and the direction in which the foramen opened into the oral cavity was found to be most frequently anteromedial (49.49%). In one skull, the greater and lesser palatine foramina were bilaterally absent. Except for the invariably present incisive canals, there were no accessory palatal foramina, which might have permitted passage of the greater palatine neurovascular bundle in lieu of the absent GPF. To the best of our knowledge, this is the first study of such a non-syndromic presentation.
Conclusion The GPF is most frequently palatal to the third maxillary molar. For an edentulous patient, the foramen may be located 14–15 mm from the mid-palatal raphe or about 12 mm anterior to the palpable pterygoid hamulus.

Keywords: greater palatine canal, greater palatine foramen, hard palate, maxillary nerve block, pterygopalatine fossa
Singapore Med J 2013; 54(3): 152-159; doi:10.11622/smedj.2013052

REFERENCES

Balaji T, Sharmila Saran R, Vaithianathan G, Aruna S
Correspondence: Dr Thotakura Balaji, balajitk@yahoo.com

ABSTRACT
Introduction The lingual, inferior alveolar and auriculotemporal nerves, being branches of the posterior division of the mandibular nerve, mainly innervate the mandibular teeth and all the major salivary glands. Anomalous communications among these branches are widely reported due to their significance to various treatment procedures undertaken in the region. This study was performed as detailed exploration of the functional perspectives of such communicating branches would further enhance the scope of these procedures.
Methods A total of 36 specimens were dissected to examine the infratemporal region. The branches from the posterior division of the mandibular nerve – namely the lingual, inferior alveolar and auriculotemporal nerves – were carefully dissected, and their branches were studied and analysed for abnormal course.
Results Communication between branches of the posterior division of the mandibular nerve was observed in four specimens. In two of the four specimens, communication between the mylohyoid and lingual nerves was observed. A rare and seldom reported type of communication between the auriculotemporal and inferior alveolar nerves is described in this study. This communicating nerve split into two to form a buttonhole for the passage of the mylohyoid nerve.
Conclusion Such communicating branches between nerves found in this study are developmental in origin and thought to maintain functional integrity through an alternative route.

Keywords: auriculotemporal, inferior alveolar, lingual, mandibular, mylohyoid
Singapore Med J 2013; 54(3): 149-151; doi:10.11622/smedj.2013051

REFERENCES

Wong MH, Lai AH, Singh M, Chew PT
Correspondence: A/Prof Paul TK Chew, ophchewp@nus.edu.sg

ABSTRACT
Introduction This prospective observational case series aimed to determine whether the lateral decubitus position, which is commonly adopted during sleep, has an effect on intraocular pressure (IOP) in normal controls.
Methods Patients without glaucoma were recruited from those visiting outpatient clinics for non-glaucomatous conditions. The left eye of each patient was included. IOP was first measured using Tono-Pen® XL applanation tonometer in the supine position, following which a second measurement was immediately obtained for the left lateral head position. Measurements were obtained with the patient lying on one soft and one hard pillow for each position, and patients remained awake during these measurements. One tonometry reading was obtained for each position. Readings were recorded only when the average of four independent readings produced a statistical confidence index of 5%. Results were analysed using the paired Student’s t-test for comparison of the means.
Results IOP in the left lateral decubitus position (17.48 ± 3.18 mmHg) was significantly higher than in the supine position (14.48 ± 3.09 mmHg) when using soft pillows (p < 0.001). When hard pillows were used, IOP in the left lateral decubitus position also exceeded that measured in the supine position (16.65 ± 3.54 mmHg vs. 13.65 ± 3.58 mmHg; p < 0.001). There was no statistically significant difference in the IOPs measured for the same position when different kinds of pillows were used.
Conclusion The lateral decubitus position adopted during sleep is associated with changes in IOP in healthy volunteers.

Keywords: intraocular pressure, sleeping posture
Singapore Med J 2013; 54(3): 146-148; doi:10.11622/smedj.2013050

REFERENCES