group 10: azni wahid naziha lazim zul zolkafly mohamed osman hassan atassi

Group 10:Azni Wahid

Naziha LazimZul Zolkafly

Mohamed OsmanHassan Atassi

Dave Martinez VP Sales Zimmer Mechanical Engineer

Dr. Michael Christie

Orthopedic Surgeon-Southern Joint Replacement Institute

Holds Design Patents

Surgical instrument by which a surgeon can:• actively separate the edges of a surgical

incision or wound• hold back underlying organs and tissues

Allows for:• Smaller incision• Greater working area

Available in many shapes/sizes

Wide Variety of retractors available for hip surgery• Choice depends surgeons training/ patient

Size of Patient Point in time in surgery

Retractors are made of surgical stainless steel

Average Duration of Hold: 15.5 Minutes

Forces:• Maximum: 48.8N• Average: 9N

Retractor Cost

Aufranc Cobra Retractor $314

Ischium Retractor $825

Sofield Retractor $360

Femoral Elevator $975

Hohmann Retractor $422

Richardson Retractor $485

Hibbs Retractor $300

Average Cost Per Set $4,820

To service 10 hip surgeries per day a minimum of 8 sets needed.

Total cost: $38,560

Model Overall Length

Handle Length

Blade Depth

Blade Width

Standard 8.75” 8” 3” 1.5”

Medium 10.75” 9.75” 4.5” 1.5”

Extra Large

14.25” 13” 6.5” 1.5”

1. Multiple versions of same retractor needed to do the same job because of varying patient size

1. Increase cost2. Increase Storage space

2. Limited Size Permutations: never exact fit to patient size

1. Decreased surgeon field of view (too large)2. Ineffective & causes injury (too small)

3. Obese Patients1. Adipose tissue wraps around retractor inefficiencies2. Hip retractors being used in knee surgery

4. Uncomfortable Handle1. Average user changes hand positions every 71 seconds2. Results in abrupt movement of retractor blade

increases chance for injury & length of recovery

Characteristics• Alterable Handle length & Blade Depth• Interchangeable handle types and blades• Ergonomic Handle• Adipose blade accessory

We propose a mechanism in order to alter the handle length and blade depth to any potential need• Current Standards averages three version of a

given retractor of various dimension• Our solution allows for much more

Customizable to exact patient dimension Optimized surgical view Ideal length to retract exact amount of tissue

• 3 retractors 1 Less number of tools Potential Cost decrease

New handle design to optimize comfort• Potential for multiple handles to be

designed in future based on user preferences

Various types of tips are used based on need of surgery & surgeon preference• Various tips can be manufactured

Surgical Staff (retractor user) have different perceptions of comfort• Various Handles Can be Manufactured

Example: • 5 tips + 5 handles= 25 retractors

Separating the two components allows for 10 components instead of 25

31% of Americans are classified as ‘obese’

Obesity rising by 2% per year 3-4 fold increase of obese patients

requiring Hip replacement Proposed Solution:

• An additional accessory to be added to retractor when operating on obese tissue to handle the increase of adipose tissue

Proof of concept designed modeled with:• Interchangeable & adjustable tip• Interchangeable & adjustable handle• Adipose Accessory

Additional tips and handles can be designed in future

Alterable Handle length & Blade Depth

Detachable adipose blade

HANDLE

BLADE

ADIPOSE BLADE

Unlock

Lock HANDLE

BLADE

BODY

1)

2)

3)

4)BladeBody

Slot/groove

Minor tweaks to locking mechanism Determine Dimensions

• Stress-Strain Analyss Protoype