Comparison on intracochlear disturbances between drilling a manual and robotic cochleostomy.

During cochlear implantation, hearing preservation is a concern. Minimizing disturbances to the cochlea and protection of the underlying endosteal membrane during the formation of a cochleostomy are considered important factors. The robotic micro-drill system tested in this article is the first example of an autonomous surgical drill successfully producing a cochleostomy, which keeps the underlying endosteal membrane intact. This study compares induced disturbances within the cochlea during formation of cochleostomy using the robotic micro-drill with that of conventional manual drilling. The disturbance of the endosteal membrane is measured using a Microscope Scanning Vibrometer at a third window, produced in the cochlea. Results show that the highest velocity amplitude measured was associated with manual drilling technique. The robotic micro-drill technique produced only about 1% of the peak velocity amplitude seen in manual drilling and exhibited much more uniform behaviour, while keeping the underlying membrane intact. The technique applied when using the robotic drill could be a major step in reducing the trauma to the cochlea, by reducing disturbance levels.

Robustness analysis of a smart surgical drill for cochleostomy.

BACKGROUND: There is a need for sensor-guided robotic devices that discriminate working conditions and media, and control interaction of tool-points with respect to tissues. At the micro-surgical scale the need is to control exact penetration through flexible tissues and to control relative motion with respect to moving or deforming tissue targets and interfaces. METHODS: This paper describes a smart surgical drill that is able to control interaction with respect to the flexing tissue to avoid penetration or to control the extent of protrusion with respect to the position of the flexible tissue interface under drilling. The sensing scheme used is able to discriminate between the variations in types of conditions posed in the drilling environment. RESULTS: The fully autonomous system is able to respond to tissue type, behaviour and deflection in real time. The system is robust in terms of different drilling angle, thickness, stiffness, and disturbances encountered. Also it is intuitive to use, efficient to set up and uses standard drill bits. CONCLUSIONS: The smart drill has been used to prepare cochleostomies in theatre and was used to remove bone tissue leaving the endosteal membrane intact. This has enabled preservation of sterility and the drilling debris to be removed prior to insertion of the electrode. Results presented in this paper suggest that the robotic smart drill is tolerant and robust on various angled drilling trajectories with respect to tissues, tissue thickness, environmental disturbances, and has been used within the operating theatre.

Time trend analysis of mastoidectomy procedures performed in Ontario, 1987-2007.

CONCLUSIONS: There has been a reduction in the number of modified radical mastoidectomy and revision mastoidectomy surgeries per head of population in Ontario between 1987 and 2007, we believe that this represents a true reduction in prevalence of cholesteatoma. The increase of cases performed at the University Hospital Network, Toronto (UHN) may represent a shift to subspecialization in the treatment of chronic ear disease. OBJECTIVE: To analyze the trends in mastoid operations for chronic middle ear disease in the Canadian province of Ontario between 1987 and 2007 and to determine whether an increasing proportion of these procedures are being performed in tertiary referral centres. METHODS: The year on year population and number of mastoid procedures performed per year in Ontario and at the UHN between 1987 and 2007 were obtained from Statistics Canada and the Ministry of Health and Long-Term Care, Ontario, respectively. Population-adjusted rates of mastoid surgery for Ontario and the UHN. These data were collated and graphically represented for trend analysis. RESULTS: The population-adjusted number of mastoid procedures for Ontario declined from 7.1 cases per 100,000 in 1986 to 4.1 cases per 100,000 in 2006. During this time the number of both modified radical mastoidectomies and revision mastoid surgeries at UHN increased.

The effect of supporting a surgeon's wrist on their hand tremor.

BACKGROUND: Operative tremor can greatly influence the outcome of certain, precise, microsurgical operations. Reducing a surgeons tremor may not only improve the operative results but decrease the operative time. Previous studies have only measured uni or bi directional tremor and therefore have been unable to calculate both the overall tremor amplitude and the tremor reduction by resting the wrists. MATERIALS AND METHODS: We measured the tremor of 21 neurologically normal volunteers while performing a micromanipulation task, with and without wrist support. Measurements were acquired in three dimensions using three accelerometers attached to the hand, allowing an overall tremor amplitude to be calculated. RESULTS: Resting the wrist on a gelled surface decreases an individuals tremor by a factor of 2.67 (P = 0). CONCLUSIONS: Supporting the wrists significantly decreases the amplitude of the tremor. Surgeons should consider using wrist supports when performing parts of operations which necessitate a high degree of accuracy.

The effect of operating time on surgeon's hand tremor.

The objective of this prospective study, performed at two tertiary referral centers in the West Midlands, was to determine if operating has an effect on a surgeon's baseline tremor. A total of 10 head and neck surgery consultants, 2 ENT registrars and 19 normal controls participated in the study. The interventions were preoperative and postoperative tremor measurements for surgeons and pre and post-days' desk work for controls, with the main outcomes measure being the percentage change in tremor. No difference in baseline tremor was determined between consultants and registrars. Operating led to an increase in hand tremor in all subjects. Tremor increases in all subjects were directly proportional to the length of the time spent in operating. Operating compared to a normal day's desk work increased tremor by a factor of 8.4. In conclusion, surgeons should be aware that their tremor will increase as an operation progresses. More complex parts should be performed as early in the day as possible, or, in the case of a very long operation, a change of surgeons may occasionally be necessary.