Ashish D. Nimbarte

A survey study of occupational pain and injury in ophthalmic plastic surgeons.

Purpose: To determine factors associated with pain/injury related to practicing ophthalmic plastic and reconstructive surgery. Methods: A 29-question electronic survey was sent to the American Society of Ophthalmic Plastic and Reconstructive Surgerys listserv. The Chi-Squared Automatic Interaction Detector technique was used to generate a decision tree using SPSS software. The levels of dendograms were limited to 8. Significance was pre-established at &agr; = 0.05. Results: One hundred thirty surveys were completed, and 72.5% reported pain associated with operating, 80.9% reported use of loupe magnification, 68.7% reported use of a headlight, 42.5% reported modification of their operating room practice, and 9.2% reported stopping operating due to pain or spine injury. Most respondents regularly exercise, with 55.7% characterizing the amount of exercise as less than necessary; 60.8% and 57.3% agreed that loupe use and headlamp use, respectively, can lead to spine problems. Chi-Squared Automatic Interaction Detector analysis found that 62.7% (n = 47) with neck pain had modified their operating room practice, compared with 13.5% (n = 7) without pain (&khgr;2 = 30.42; df = 1; p < 0.001); All surgeons that had to stop operating (n = 9) had tried modifying their operating room practice; over half (57.6%, n = 38) of practicing surgeons had changed their operating room practice (&khgr;2 = 6.09; df = 1; p = 0.014). The majority who exercised 5 hours or less had modified their operating room practice (70.2%, n = 33), compared with 26.3% (n = 5) who exercised more. Conclusions: Many oculoplastic surgeons experience discomfort due to operating, and an alarming minority have stopped operating due to pain or neck injury. Participants identified loupe and headlamp use as a special concern.

The changes of lumbar muscle flexion–relaxation response due to laterally slanted ground surfaces

Lifting tasks performed on uneven ground surfaces are common in outdoor industries. Previous studies have demonstrated that lifting tasks performed on laterally slanted ground surfaces influence lumbar muscle activation and trunk kinematics. In this study, the effect of laterally slanted ground surfaces on the lumbar muscle flexion–relaxation responses was investigated. Fourteen participants performed sagittal plane, trunk flexion–extension tasks on three laterally slanted ground surfaces (0° (flat ground), 15° and 30°), while lumbar muscle activities and trunk kinematics were recorded. Results showed that flexion–relaxation occurred up to 6.2° earlier among ipsilateral lumbar muscles with an increase in laterally slanted ground angle; however, the contralateral side was not affected as much. Our findings suggest that uneven ground alters the lumbar tissue load-sharing mechanism and creates unbalanced lumbar muscle activity, which may increase the risk of low back pain with repeated exposure to lifting on variable surfaces. Practitioner Summary: Uneven ground surfaces are ubiquitous in agriculture, construction, fishing and other outdoor industries. A better understanding of the effects of laterally slanted ground surfaces on the interaction between passive and active lumbar tissues during lifting tasks could provide valuable knowledge in the design of preventive strategies for low back injuries.

Comparison of Current U.S. and Canadian Cigarette Pack Warnings

Cigarette smoking is the single most preventable cause of death in the United States. From 1985 to date, one of four mandatory cigarette warnings proposed by the Comprehensive Smoking Education Act of 1984 has been displayed on cigarette packages. In addition to cigarette warnings, states like California, Massachusetts, Arizona, Oregon and Maine have implemented “Tobacco Control Programs” (TCP) to reduce the overall number of smokers. However, the decline in the rate of smoking is not occurring fast enough to meet the national health objective by 2010. The present U.S. cigarette warnings are verbal in form and provide information, which is inadequate but appropriate to make it legally adequate. On the other hand, warnings in other countries such as Canada and Brazil are more descriptive and specific and are accompanied by vivid and sometimes gruesome pictures. In the present study, six pictorial Canadian labels and four U.S. verbal labels were analyzed for potential effectiveness among eighty subjects using a survey questionnaire. The survey findings are compared with recent Canadian smoking data. It is concluded that placing pictorial labels on cigarette packages in the U.S. will allow the product to carry warnings that potentially provide better results than current verbal messages and less TCP funds will need to be used.

Effect of driving experience on visual behavior and driving performance under different driving conditions

Drivers’ ability to perform the primary task of driving a vehicle and be able to handle the interference caused by the secondary tasks such as the use of cell phone is greatly influenced by their driving experience. In this study, thirty-eight drivers with different levels of driving experience were studied to evaluate their driving performance during simple versus complex driving tasks performed with and without cell phone. The driving performance was evaluated by studying the visual behavior of the drivers using eye-tracking systems, driving error, and subjective workload assessment tool. Results demonstrate that the novice drivers fixated more on the dashboard area (36.33%) than on the front and center view (14.33%). On the other hand, the experienced drivers fixated more on the front and center (39.5%) as compared to the dashboard area (12%). Same trend was observed for complex driving but with lower percentage of total fixations than the simple driving conditions. The visual distraction caused by secondary task of cell phone use contributes to the decline in driving performance. Although all drivers reported higher workloads during driving while using cell phones and committed more driving errors, the errors were comparatively lower for experienced drivers than the inexperienced drivers.

Neck Postures and Cervical Spine Loading Among Microsurgeons Operating with Loupes and Headlamp

OCCUPATIONAL APPLICATIONS Surgical tasks performed using loupes and headlamps were examined to identify exposures to physical risk factors for work-related musculoskeletal disorders in the neck among microsurgeons. Surgeons who use loupes and headlamps were found to spend extensive time periods working in non-neutral head–neck postures. These postures, and the use of loupes and headlamps, were found to be associated with an increased loading of the cervical spine, which might cumulatively contribute to occupational neck musculoskeletal disorders. To develop effective control strategies, future studies should focus on the impact of design features of loupes (e.g., mount angles, weight, and shape) on head–neck postures during surgical tasks. TECHNICAL ABSTRACT Background: Work-related musculoskeletal disorders in the neck are common among microsurgeons who operate with loupes and headlamps. Published surveys indicate that microsurgeons across many subspecialties believe that loupes contribute to neck musculoskeletal disorders. However, objective data on head–neck posture and cervical loading during surgical tasks performed using loupes and headlamps are currently lacking. Purpose: This study will assess exposures to physical risk factors for neck musculoskeletal disorders during surgical tasks performed using loupes and headlamp. Methods: A field study was performed in operating rooms to measure the head–neck postures commonly used by three ophthalmic plastic surgeons; a subset of microsurgeons. Posture data were used as input to a biomechanical model to estimate cervical spine loading. Results: During nearly 85% of the time spent operating, surgeons adopted asymmetrical head–neck postures characterized by either bending or rotation of >15°, coupled with flexion of >15°. Postures consisting of flexion ≥45°, 15°–30° bending, and 15°–45° rotation produced significantly higher biomechanical loading of the cervical spine compared to near-neutral postures (i.e., flexion, bending and rotation between 0° and 15°). This loading was further exaggerated by the weight of loupes and headlamp. Conclusions: Non-neutral head–neck postures demanded by the dexterous operating tasks performed using loupes and headlamps could be important biomechanical risk factors for cervical musculoskeletal disorders among microsurgeons.

Biomechanical loading of the shoulder complex and lumbosacral joints during dynamic cart pushing task

The primary objective of this study was to quantify the effect of dynamic cart pushing exertions on the biomechanical loading of shoulder and low back. Ten participants performed cart pushing tasks on flat (0°), 5°, and 10° ramped walkways at 20 kg, 30 kg, and 40 kg weight conditions. An optoelectronic motion capturing system configured with two force plates was used for the kinematic and ground reaction force data collection. The experimental data was modeled using AnyBody modeling system to compute three-dimensional peak reaction forces at the shoulder complex (sternoclavicular, acromioclavicular, and glenohumeral) and low back (lumbosacral) joints. The main effect of walkway gradient and cart weight, and gradient by weight interaction on the biomechanical loading of shoulder complex and low back joints was statistically significant (all p < 0.001). At the lumbosacral joint, negligible loading in the mediolateral direction was observed compared to the anterioposterior and compression directions. Among the shoulder complex joints, the peak reaction forces at the acromioclavicular and glenohumeral joints were comparable and much higher than the sternoclavicular joint. Increased shear loading of the lumbosacral joint, distraction loading of glenohumeral joint and inferosuperior loading of the acromioclavicular joint may contribute to the risk of work-related low back and shoulder musculoskeletal disorder with prolonged and repetitive use of carts.

The assessment of material-handling strategies in dealing with sudden loading: the effect of uneven ground surface on trunk biomechanical responses.

As a major risk factor of low back injury, sudden loading often occurs when performing manual material-handling tasks on uneven ground surfaces. Therefore, the purpose of the current study was to investigate the effects of a laterally slanted ground on trunk biomechanical responses during sudden loading events. Thirteen male subjects were subjected to suddenly released loads of 3.4 and 6.8 kg, while standing on a laterally slanted ground of 0°, 15° and 30°. The results showed that 8.3% and 5.6% larger peak L5/S1 joint compression forces were generated in the 30° condition compared with the 0° and 15° conditions, respectively. The increase of L5/S1 joint moment in the 30° condition was 8.5% and 5.0% greater than the 0° and 15° conditions, respectively. Findings of this study suggest that standing on a laterally slanted ground could increase mechanical loading on the spine when experiencing sudden loading. Practitioner Summary: Sudden loading is closely related to occupational low back injuries. The results of this study showed that the increase of slanted ground angle and magnitude of load significantly increase the mechanical loading on the spine during sudden loading. Therefore, both of these two components should be controlled in task design.

Cervical occupational hazards in ophthalmic plastic surgery.

Purpose of review To increase awareness of cervical musculoskeletal disorders (cMSD) in ophthalmic plastic surgeons (OPS) and review strategies for management and prevention. Recent findings There are objective data that show OPS spend the majority of their time operating in awkward, prolonged, static, asymmetric postures. These postures increase cervical load and cMSD. Loupes and headlamps further increase this cervical loading by 40%. Risk for cMSD is not limited to the operating room. Muscular demands in the anterior deltoid and cervical trapezius are increased in slit lamp biomicroscopy and indirect ophthalmoscopy. Furthermore, the majority of the office visit is spent keyboarding into the electronic medical record which is associated with cMSD. Habitual postural faults result from these cumulative exposures. These must be addressed to prevent further insult and debilitating injury. Successful management requires education in neutral posture, therapeutic exercise, environmental adjustments in the workplace and home, and supported neutral sleep posture. Summary The risks of cMSD in OPS are well established, and nearly 10% of cervical injury will end a career. Neck pain must not be ignored, and experienced professional help is critical. A long-term approach that incorporates exercise, manual therapy, and education is essential for management and prevention.

Comparison of Fourier and wavelet analysis for fatigue assessment during repetitive dynamic exertion.

The comparative ability of the Fourier transform (FFT) and discrete wavelet transform (DWT) algorithms in assessing muscle fatigue during sub-maximal repetitive dynamic exertion was investigated in this study. Surface electromyography data recorded from the upper trapezius muscle during forty minutes of repetitive upper extremity exertion performed by 10 male participants were used in the analysis. Multi-model regression analysis was performed to study the trend in the power values of the different frequency bands estimated using the FFT and DWT algorithms. Less variability and higher statistical significance was observed for the power value trend computed using the DWT algorithm compared to the FFT algorithm. The regression models provided a better fit for the power values estimated under more fatigued condition compared to the less fatigued condition. The lower frequency bands of 23-46 Hz and 46-93 Hz exhibited the expected and consistent power trend independent of the algorithm (DWT or FFT) used. For the exertions tested in this study, a cubic or curvilinear model explained the fatigue development process with a higher precision than the linear models.

Impact of shoulder position and fatigue on the flexion–relaxation response in cervical spine

BACKGROUND Neck pain is common among general population with a high prevalence among the people who are routinely exposed to prolonged use of static head-neck postures. Prolonged static loading can cause localized muscle fatigue which may impact the stability of the cervical spine. In this study, flexion-relaxation phenomenon was used to study the post fatigue changes in the stability of cervical spine by evaluating the synergistic load sharing between muscles and viscoelastic elements. METHODS Thirteen male participants were recruited for data collection. The variables that influence cervical flexion-relaxation were studied pre- and post-fatigue using neutral and shrugged shoulder postures. The Sorensen protocol was used to induce neck extensor fatigue. Surface electromyography and optical motion capture systems were used to record neck muscle activation and head posture, respectively. Findings The flexion-relaxation phenomenon was observed only in the neutral shoulder position pre- and post-fatigue. The flexion relaxation ratio decreased significantly post-fatigue in neutral shoulder position but remained unchanged in shrugged shoulder position. The onset and offset angles and the corresponding durations of the silence period were significantly affected by the fatigue causing a post-fatigue expansion of silence period. Interpretation The muscular fatigue of neck extensors and shoulder position was found to modulate the cervical flexion-relaxation phenomenon. Early shifting of load sharing under fatigued condition indicates increased demands on the passive tissues to stabilize the cervical spine. Shrugging of shoulder seems to alter muscular demands of neck extensors and make cervical flexion-relaxation phenomenon disappear due to continuous activation of the neck extensors.