Computed Tomographic Study of Occipital Thickness in Ethnic Malays

@#Introduction: Occipitocervical fusion is performed to address craniocervical and atlantoaxial instability. A screw of at least 8mm is needed for biomechanical stability. Occipital thickness of Malay ethnicity is unknown, and this study presents the optimal screw placement positions for occiput screw in this population. This was a retrospective crosssectional study of 100 Malays who underwent computed tomography (CT) scan for brain assessment. To measure the occipital bone thickness of Malay ethnicity at the area of common screw placement for occipitocervical fusion. The subject’s data was obtained from the institutional database with consent from the administrations and the patients. None of the patients had any head and neck pathology. Materials and methods: The subject’s data was obtained from the institutional database with consent from the administrations and the patients. None of the patients had any head and neck pathology. Computed tomography (CT) of 100 Malay patients who underwent head and neck CT were analysed, based on our inclusion and exclusion criteria. Measurements were taken using a specialised viewer software where 55 points were measured, followed a grid with 10mm distance using external occipital protuberance (EOP) as the reference point. Results: There were 57 males and 43 females of Malay ethnicity with a mean age of 36.7 years analysed in this study. The EOP was the thickest bone of the occiput which measured 16.15mm. There was an area of at least 8mm thickness up to 20mm on either side of the EOP, and at level 10mm inferior to the EOP. There is thickness of at least 8mm, up to 30mm inferior to the EOP at the midline. The males have significantly thicker bone especially along the midline compared to females. Conclusion: Screws of at least 8mm can be safely inserted in the Malay population at 20mm on either side of the EOP at the level 10mm inferior to the EOP and up to 30mm inferior to the EOP at the midline.

Are Dropped Bone Grafts Safe to be Re-used? - An Experimental Study Comparing Efficacy of Chlorhexidine, Povidone-Iodine and Alcohol

@#Introduction: A dilemma arises when a bone graft or fracture fragment is accidentally dropped on the operation theatre floor and becomes contaminated. This study aimed to determine the efficacy of simple and readily available antiseptic solutions in disinfecting contaminated bones. Materials and methods: This experimental study involved 225 bone specimens prepared from discarded bone fragments during a series of 45 knee and hip arthroplasty surgeries. The bone fragments were cut into five identical cubes and were randomly assigned to either control (positive or negative), or experimental groups (0.5% chlorhexidine, 10% povidone-iodine or 70% alcohol). The control negative was to determine pre-contamination culture. All bone specimens, except the control negative group were uniformly contaminated by dropping on the operation theatre floor. Subsequently, the dropped bone specimens except for the control positive group, were disinfected by immersing in a respective antiseptic solution for 10 minutes, before transported to the microbiology laboratory for incubation. Results: The incidence of a positive culture from a dropped bone fragment was 86.5%. From the 37 specimens sent for each group, the incidence of positive culture was 5.4% (2 specimens) after being disinfected using chlorhexidine, 67.6% (25 specimens) using povidone-iodine and 81.1% (30 specimens) using alcohol. Simple logistic regression analysis demonstrated that chlorhexidine was significantly effective in disinfecting contaminated bones (p-value <0.001, odd ratio 0.009). Povidone-iodine and alcohol were not statistically significant (p-value 0.059 and 0.53, respectively). Organisms identified were Bacillus species and coagulase negative Staphylococcus. No gram-negative bacteria were isolated. Conclusion: A total of 0.5% chlorhexidine is effective and superior in disinfecting contaminated bones.

Incidence of Varus Malalignment Post Interlocking Nail in Proximal Femur Shaft Fractures Comparing Two Types of Entry Points

Introduction: Osteosynthesis of the femur using an interlocking nail is the gold standard for treating diaphyseal fractures of the femur. There are two established entry points for the antegrade interlocking nails which is the piriformis fossa or the greater trochanter. It has been reported that varus malalignment was frequently seen in proximal femur fracture which were treated with interlocking nail utilizing the greater trochanter entry point. The study was done to find out if the problem was of significance. Materials and Methods: This was a retrospective study which included 179 patients with femur fractures which were treated from January 2013 till September 2015 in one Hospital. They were treated with interlocking nail either by utilizing the piriformis fossa (PF) or the greater trochanter (GT) entry points. Post-operative radiographs of the femur were used to measure the varus deformity. Results: Out of 179 patients, there were 5 patients who were reported to have unacceptable varus malalignment (2.79%). These 5 patients were out of the 88 (5.68%) patients utilizing the greater trochanter as the entry point. The same 5 patients were out 90 patients that were diagnosed with proximal femur shaft fractures (5.55%). Analysis with logistic regression was statistically not significant. Conclusion: There was higher rate of varus malalignment seen in proximal femur shaft fractures treated with interlocking nails utilizing the greater trochanter entry point. The incidence of varus malalignment was not significant statistically. Key Words: interlocking nail; greater trochanter entry point; varus deformity; femur shaft fracture