What is a Thumb Spica Splint?

A thumb spica splint is a type of hand cast that is designed to protect and immobilize the thumb. It is commonly used in emergency rooms and orthopedic surgeon's offices to aid in the healing of strains, sprains, and minor fractures of the lower thumb or wrist. The application procedure is fairly straightforward, and can be performed by a physician or trained nurse in a matter of minutes. This splint is usually removed within one or two weeks so a doctor can re-evaluate an injury and determine if further medical or surgical treatment is necessary.

Many different hand injuries can necessitate a thumb spica splint as a form of primary treatment or temporary immobilization. In the case of sprains and strains, splinting the thumb is often the only physical treatment necessary to promote recovery. With the thumb joint protected and held in place, it can heal without worry of suffering another injury. Severe fractures and torn ligaments in the thumb also require splinting, though only as a means of temporarily protecting the joint until a patient can undergo surgery. In addition, a post-surgical splint may be applied to encourage faster healing time after bones are set.

The procedure for setting a thumb spica splint is familiar to most emergency room physicians and nurses. First, the thumb, wrist, and forearm are fitted with a thin sock-like sleeve called a stockinette to protect the skin. Medical tape, padding, and bandages are wrapped around the stockinette and the thumb is secured at the proper angle. A layer of plaster is measured, cut, and softened in water. The doctor or nurse then wraps the soft plaster around the padding and molds it into the correct shape.

The plaster cast hardens as it dries, immobilizing the thumb and wrist. Another layer of bandages is wrapped and taped around the hardening cast to complete the procedure. Once the thumb spica splint is dried, a doctor can make sure it is not too tight by wiggling the exposed end of the thumb and other fingers. The fingers should be their normal color and not tingling.

Depending on the reason for splinting and the severity of an injury, a patient may be given pain medications, anti-inflammatory drugs, and instructions for home care. In general, people are told to elevate their thumbs and avoid getting their splints wet. When it is time for a thumb spica splint to be removed, a doctor simply needs to unwrap the bandage and cut away the plaster. Further treatment decisions are made after a careful reexamination of the injury.