Personalized Scalp Tourniquets
Alopecia (hair loss) is a common consequence of cancer treatment known to have a profound impact on quality of life. Tourniquet technologies have been investigated from the mid-1960s to early 1980s as a strategy for preventing chemotherapy-induced alopecia (CIA) but their ambiguous results precluded incorporation into any standard of treatment . Fundamental advances inherent in personalized tourniquet systems enable the optimal, safe, comfortable and reliable stoppage of penetration of arterial blood into the scalp during infusion of chemotherapeutic agents . Thus personalized tourniquet systems offer significant potential to safely prevent CIA, thereby improving quality of life with low treatment cost and low impact on treatment times and workflow .
What is chemotherapy-induced alopecia?
Chemotherapy-induced-alopecia (CIA), is hair-loss that occurs as a result of chemotherapy treatment. Many drugs used to treat cancer have a high probability of causing alopecia and patients typically lose their hair within a few weeks after the beginning of the treatment.
CIA is one of the most devastating side-effects of cancer treatment and has a profound impact on the quality of life of patients, particular female and young patients undergoing breast cancer treatment. According to several studies many women report that it is more difficulty to cope with hair loss than the loss of their breast because it is outwardly visible to others, affects their femininity and is a constant reminder of their treatment 
Why does CIA occur?
Each hair follicle in the scalp has a bulbous base of which the cells of the hair shaft grow . Hair growth occurs as these cells divide, are forced upwards and emerge at the skin. These cells are nourished by the blood supply into the scalp which is outside of the skull as shown in Figure 1.
Chemotherapy uses cytotoxic drugs to destroy the rapidly dividing cancer cells in the body. Unfortunately, chemotherapy cannot distinguish between cancer cells and healthy cells which rapidly divide such as hair follicle cells. Chemotherapy drugs in the bloodstream are carried by the scalp blood supply to the hair follicles and destroy the rapidly dividing cells in the hair bulb. This leads to the atrophy of the hair bulb which causes the hair follicle to fall out during washing and combing.
Prevention of CIA
Various strategies for improving quality of life by preventing CIA have been investigated. Recently, cold caps have been used in an effort to stop arterial blood flow at hair follicles by cooling the scalp . However, cooling technology is expensive and cumbersome, and has significant impact on clinic configuration, clinic workflow and time. Reported outcomes have been mixed, but typical time during which the scalp was presumably ischemic in the region of hair follicles ranged from 2 hours to over 5 hours .
Previously reported usage of scalp tourniquets
From mid-1960 to early 1980s, tourniquets technologies were investigated as a means of stopping the penetration of arterial blood containing chemotherapeutic agents into the scalp and hair follicles [2, 5-8]; their ambiguous results precluded incorporation into any standard of treatment.
The tourniquet technologies and settings used in such early investigations are now considered to be unsafe, ineffective and obsolete . Their use likely allowed arterial penetration of agents in many instances and excessive pain leading to discontinuation in others, e.g. tourniquet pressures could not be set optimally relative to a patient’s personalized scalp occlusion pressure and instead were set arbitrarily or erroneously based on the patient’s systolic blood pressure; accuracy and reliability of mechanical pressure regulation was poor; and limb tourniquet cuffs would not apply pressure safely and uniformly around the scalp. Despite these and other flaws in the reported methodologies, no tourniquet-related patient injuries were reported in these studies .
New personalized scalp tourniquet system
A novel personalized scalp tourniquet system includes a scalp protection sleeve placed over the patient’s scalp, a specially designed scalp tourniquet cuff placed over the scalp protection sleeve, and a surgical-grade personalized tourniquet instrument connected to the scalp tourniquet cuff .
The scalp protection sleeve and the scalp tourniquet cuff are designed to increase patient comfort, enable snug and consistent cuff application, and minimize tourniquet pressure gradients beneath the cuff. The personalized tourniquet instrument measures the patient’s Distal Occlusion Pressure (DOP) and recommends a Personalized Tourniquet Pressure (PTP) based on DOP, allowing the use of the lowest and safest tourniquet pressure to stop arterial blood flow into the scalp. By stopping arterial blood carrying the cytotoxic drugs from entering the scalp, chemotherapy-induced alopecia should be prevented.
DOP is the minimum pressure required, at a specific time in a specific tourniquet cuff applied to a specific patient’s limb at a specific location, to stop the flow of arterial blood distal to the cuff. For scalp tourniquets, DOP is affected by variables including the elevation of the head relative to the heart, snugness and consistency of tourniquet cuff application to the head, characteristics of the selected tourniquet cuff, cuff width-to-head-circumference ratio, hair volume and length beneath the scalp, scalp muscle tone and muscle tension, presence and type of scalp protection sleeve, and physiologic characteristics of the patient including systolic blood pressure, head temperature, and vascular health.
Personalized scalp tourniquet systems are optimally effective in minimizing tourniquet pressure while assuring full stoppage of arterial blood flow distal to the tourniquet cuff. The advances in personalized tourniquet systems described above have the potential to significantly improve quality of life by safely stopping penetration of arterial blood flow into the scalp during chemotherapy, with low treatment cost and low impact of treatment times and flow. Clinical studies are ongoing to determine the extent to which CIA can be prevented using this technology.
 Breast Cancer.org [Internet]. Ardmore (PA): c2016. Cold Caps; 2015 Dec 18 [cited 2016 Feb 12]; Available from: http://www.breastcancer.org/tips/hair_skin_nails/cold-caps
 McEwen JA, Jameson M, Jeyasurya J, Glinz KL, inventors; Western Clinical Engineering Ltd., assignee. Personalized tourniquet methods and apparatus. United States patent application US 14/837,999. 2015 Aug 27.