Analysis of temperature in conventional and ultrasonically-assisted drilling of cortical bone with infrared thermography

BACKGROUND

Bone drilling is widely used in orthopaedics, dental and neurosurgeries for repair and fixation purposes. One of the major concerns in drilling of bone is thermal necrosis that may seriously affect healing at interfaces with fixtures and implants. Ultrasonically-assisted drilling (UAD) is recently introduced as alternative to conventional drilling (CD) to minimize invasiveness of the procedure.

OBJECTIVE

This paper studies temperature rise in bovine cortical bone drilled with CD and UAD techniques and their comparison using infrared thermography.

METHODS

A parametric investigation was carried out to evaluate effects of drilling conditions (drilling speed and feed rate) and parameters of ultrasonic vibration (frequency and amplitude) on the temperature elevation in bone.

RESULTS

Higher levels of the drilling speed and feed rate were found responsible for generating temperatures above a thermal threshold level in both types of drilling. UAD with frequency below 20 kHz resulted in lower temperature compared to CD with the same drilling parameters. The temperatures generated in cases with vibration frequency exceeding 20 kHz were significantly higher than those in CD for the range of drilling speeds and feed rates. The amplitude of vibration was found to have no significant effect on bone temperature.

CONCLUSIONS

UAD may be investigated further to explore its benefits over the existing CD techniques.

Experimental and numerical investigation of cracking behavior of cortical bone in cutting

BACKGROUND

Bone cutting is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Common complications associated with the process are mechanical damage linked with excessive levels of penetration force. Larger forces may produce minor cracks in bone which may seriously affect strength of fixation and may delay the healing process.

OBJECTIVE

This paper investigates cracking behavior in the microstructure of cortical bone in cutting using experimental and numerical techniques.

METHODS

Experiments were performed on cortical bone to study the mechanics of crack propagation and evaluate the extent of crack with the drilling force and amount of penetration. Finite element (FE) simulations were performed to visualize the extension and arrest of the cracks in bone microstructure.

RESULTS

The length of crack was found to be strongly influenced by the drilling force and amount of drill penetration. Osteon were seen to deflect the cracks at their boundaries. Crack propagation in bone microstructure was observed to depend on anatomical direction. Numerical simulations predicted the direction of crack propagation and found osteon boundaries to act as barrier to the cracks.

CONCLUSIONS

Lower drilling force may be used in cutting the bone to avoid cracks in the bone tissue. A detailed FE model based on fracture data of cortical bone is to be produced to simulate cracking of bone microstructure.

Comparative study of conventional and ultrasonically-assisted bone drilling

BACKGROUND

Bone drilling is a well-known surgical procedure in orthopaedics and dentistry for fracture treatment and reconstruction. Advanced understanding of the mechanics of the drill-bone interaction is necessary to overcome challenges associated with the process and related postoperative complications.

OBJECTIVE

The aim of this study was to explore the benefits of a novel drilling technique, ultrasonically-assisted drilling (UAD), and its possible utilization in orthopaedic surgeries.

METHODS

The study was performed by conducting experiments to understand the basic mechanics of the drilling process using high speed filming of the drilling zone followed by measurements to quantify thrust force, surface roughness and cracking of the bone near the immediate vicinity of the hole with and without ultrasonic assistance.

RESULTS

Compared to the spiral chips produced during conventional drilling (CD), UAD was found to break the chips in small pieces which facilitated their fast evacuation from the cutting region. In UAD, lower drilling force and better surface roughness was measured in drilling in the radial and longitudinal axis of the bone. UAD produced crack-free holes which will enhance postoperative performance of fixative devices anchoring the bone.

CONCLUSIONS

UAD may be used as a possible substitute for CD in orthopaedic clinics.

Strengthening the Pharmacovigilance Programme in Nepal

The aims of pharmacovigilance are early recognition of previously unknown adverse drug reactions (ADRs), recognition of changes in frequency of known ADRs, identification of risk factors and mechanism of ADRs, quantitative analysis of benefit/risk ratio and dissemination of safety information for rational drug prescribing and regulation. The pharmacovigilance programme in Nepal is a recent development. The Department of Drug Administration (DDA) took the initiative to set up a pharmacovigilance program in 2002; however, it was initiated systematically only after two years. DDA acts as the National Pharmacovigilance Centre (NPC). It collects ADR case reports from the Regional Pharmacovigilance Centre (RPC). Currently there are six RPCs operating in the country. The current reporting trends suggest high under-reporting of suspected ADRs. This paper is a review of those studies which are focused on pharmacovigilance and healthcare professionals’ perspectives on ADR reporting in Nepal. It also recommends the possible ways to improve the ADR reporting based on the context of Nepal.DOI: http://dx.doi.org/10.3126/nje.v3i1.8286 Nepal Journal of Epidemiology 2013;3 (1): 230-235

A research methodology workshop on ‘Social issues in use of medicines’ – cooperation between institutions and participant feedback

A research methodology workshop on social issues in use of medicines was conducted at Pokhara, Nepal from December 21st to 24th, 2008. The present study was conducted to obtain detailed participant feedback about the workshop and obtain suggestions for improvement. The participants’ knowledge was assessed at the start of the workshop and on the final day by noting their agreement with a set of 40 statements using a modified Likert-type scale. The areas of qualitative research, statistics, research methodology, drug use, pharmacovigilance, journal and general were covered. Certain statements were negative and their scores were reversed. The total score was calculated. The median total scores were compared among various subgroups of respondents. Session evaluation was done at the end of each session. A total of twenty-five participants attended the sessions. The workshop significantly improved the median total scores. Significant improvements were also seen in the subcategories Statistics and Journal. The scores of certain statements were low. The evaluation scores of certain sessions were low. The overall participant opinion about the workshop was positive. Occasional problems with accent of the facilitator and lack of internet access were major problems noted. Some participants felt the workshop was too hectic. Journal of College of Medical Sciences-Nepal,2012,Vol-8,No-1, 60-67 DOI: http://dx.doi.org/10.3126/jcmsn.v8i1.6829

Warthin's tumour with coexistent tuberculosis

A 81-year-old man presented with a 2-month history of swelling of the right angle of the jaw. On histopathological examination a diagnosis of Warthin's tumour with coexistent tuberculosis of the parotid gland was made. PCR for tuberculosis was positive. Tuberculosis of the parotid gland is very rare and coexistence with Warthin's tumour is extremely rare. This case is being reported for its rarity.

Ecological Health Risk of Buriganga River, Dhaka, Bangladesh

The efforts of modern civilization to create an environment to meet human aspirations have successfully resulted in constant improvements of our lifestyle, but it has increased risks to human and ecological health. This situation has motivated many scientists throughout the world to analyze the environmental factors that can affect our health or ecology and to calculate the levels of risk. In Bangladesh development activities and utilization of the river pose a great threat to the health of the existing natural environmental system, particularly for the important river Buriganga of the capital city, Dhaka, due to the pollution of the river water. A study was carried out to observe the ecological health hazards of the Buriganga river and their risk to human health. Several random samples of water were collected from different spots on the river from September to December 2006. The samples were analyzed to determine water quality and associated environmental health risks. The study revealed that the water is high in biological oxygen demand (BOD), chemical oxygen demand (COD), phosphate (PO4 -3), ammonia, organic matters and nutrients, etc. It also revealed huge environmental health risks and possible ecological disruption of this river. Finally, the research recommends a sustainable policy framework on how the pollution could significantly be reduced by using different appropriate measures. Key words: Environmental health risk, ecological disruption, sustainable policy, water quality, Buriganga river, Bangladesh  doi: 10.3126/hn.v3i0.1915 Hydro Nepal:Journal of Water, Energy and Environment Issue No. 3, July 2008. Page: 25-28