Support System for Lumbar Puncture Procedure Mid Semester Paper October 25 2006 Team Members Lee Linstroth Malini Soundarrajan Amanda Feest Chelsea Wanta Client Cynthia M Carlsson M D M S UW Medical School Advisor Kristyn Masters Professor Ph D UW College of Engineering Problem Statement To design a specialized support system to use for lumbar puncture procedures in the sitting position Proper positioning of the patient to open up the space between the lumbar backbones is critical for success of the procedure Keeping the patient comfortable while maximizing the curve of the lower back to optimize the access to the lumbar interspace is important however it remains a difficult challenge using current positioning techniques Currently there is no proper seating equipment to optimize the position and comfort of the patient during the procedure The use of the lumbar puncture technique in research is becoming increasingly significant Project Motivation Our client Dr Cynthia M Carlsson strives to understand the effects of vascular risk factors and their treatments on the development and progression of Alzheimer s disease She is currently conducting a clinical trial to evaluate how cholesterol lowering medications called statins affect blood spinal fluid cognitive and MRI perfusion biomarkers for Alzheimer s Disease in asymptomatic middle aged adults at risk for the disease To study these changes Dr Carlsson collects cerebral spinal fluid from patients using the lumbar puncture procedure Background Information The lumbar puncture procedure is performed by inserting a needle into the lower back between the lumbar backbones Insertion is much easier when the spine is curved because it facilitates the separation of the lumbar backbones Currently this procedure is done with the patient sitting on the edge of the bed the feet propped up with a chair and the head resting on a doughnut shaped pillow on the bedside table The patient s arms also rest on the bedside table See Figure 1 This positioning is uncomfortable for the patient because the patient s head is approximately 3 5 inches from the table which is not permit proper air flow Also the patient s knees are typically in contact with the bottom of the table which adds further discomfort The patient s arms are at the same level of the head which is also uncomfortable Since the arms are above the heart the patient s arms are more likely to experience a lack of blood flow Since the patient is not supported at the sides and the bedside table is on wheels there is the risk that the patient will fall to the side or that the table will move away from the patient during the procedure In this case the spine is likely to become misaligned In order to prevent this from happening additional persons are required to help position and secure the patient during the procedure Figure 1 Current positioning of a patient for lumbar puncture procedure Left Picture Notice the patient s knees are in contact with the bottom of the table Also notice that the patient s head is very close to the table and the patient s arms are level with the head which is less comfortable than if they were lower than the head Existing Equipment Currently there is no equipment specially designed for lumbar puncture procedures however researchers at the Department of Neurology at Johns Hopkins Medical Institution have utilized massage chairs for spinal catheter insertion See Figure 2 1 Researchers found that the massage chair provides a stable platform that allows patients to maintain proper position without effort and without the need for additional personnel to monitor the patient The head rest minimizes the possibility of breathing obstruction and the seated position allows for proper spinal alignment One drawback to this technique is that patients who are unable to straddle their legs over the seat may be unable to sit on the chair A second drawback that was not reported by researchers at Johns Hopkins but that our client brought to our attention is that this massage chair does not maximize curvature of the spinal cord possibly due to the limited range of adjustability of the chair Figure 2 The massage chair is used by researchers at Johns Hopkins for the lumbar puncture procedure Notice that the procedure can be done without the need for additional personnel Also the patients breathing remains unobstructed and the arms are at approximately heart level facilitating a comfortable sitting position for the patient Left picture Notice that this seat may be difficult for geriatric patients to sit in http www neurology org cgi content full 58 12 1859 cookietest yes Design Requirements Our design must provide proper positioning of the back during lumbar puncture procedures This means that the spinal column must be curved at a maximum point while maintaining patient comfort The device must be used in conjunction with the bed Therefore the patient should sit on the edge of the bed and the device should support the head feet and arms in a way that is comfortable and compatible with varying patient body sizes The device must be easily transported throughout the hospital and must be able to fit in all the hospital rooms The device must cost less than 500 Refer to PDS in Appendix 1 Design 1 One Piece Unit Our first proposed design is a one piece unit where the head arm and foot rests are attached to a central column The central column is adjustable and can vary in length using a system of push button tabs similar to those used on standard crutches The head rest is directly attached to this central rod and can be adjusted vertically by raising and lowering the central column Two cuffs one attached to the foot rest and one attached to the arm rest are placed over the central rod and can slide vertically and are held in place with a screw that can be tightened and loosened by hand with an adjustment knob Figure 3 Diagram of proposed one piece unit Central column arm rest and foot rest are independently adjustable The headrest raises and lowers vertically with the central column For simplicity the central column push button tabs are not shown in this diagram 43 25 Wheels The entire one piece unit is supported by a base which has two supporting rods connecting to the central rod For transportation the base of the unit has wheels that can be locked in place with brakes when being used by the patient Some advantages of the design include ease of transportation and proper weight distribution
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