What is Proximal Humerus Resection and Reconstruction?
The proximal humerus is a common site for benign, primary malignant, or metastatic neoplasms. Resection of the proximal humerus becomes necessary for the control of primary and metastatic bone tumors. The defects caused by the resection may spare the deltoid and shoulder cuff muscles or remove them. Reconstruction of these defects and restoration of shoulder function may be achieved by a variety of techniques.
Some of the proximal humerus reconstruction and stabilization methods include allograft, endoprosthesis, megaprosthesis, alloprosthetic composite (APC), and more recently, reverse shoulder arthroplasty (RSA). The main objective of these methods is not only to reconstruct the resected bone segment, but also to restore a mobile and stable shoulder without any functional limitations.
There is no general agreement on the ideal method for reconstruction after resection. The choice of the method depends upon the condition of the soft tissues at the end of the resection. However, endoprosthetic reconstruction is the commonly employed technique for reconstruction of large proximal humeral defects.
Anatomy of the Humerus
The humerus is the bone that forms the upper arm. It articulates with the glenoid cavity of the scapula (shoulder blade) to form the shoulder joint and with the lower arm bones – the ulna and radius – to form the elbow joint. The proximal humerus is the upper end of the arm bone that forms the shoulder joint. The humerus is broadly divided into the head, neck, and shaft region. Just below the head are two processes called the greater and lesser tubercles, which form the sites of attachment for the rotator cuff muscles.
Indications for Proximal Humerus Resection and Reconstruction
Your doctor will recommend proximal humerus resection and reconstruction after considering a number of factors including the extent of the tumor, its location, its radiographic features, the underlying diagnosis, your level of pain and expected survival. Surgery is recommended if the tumor in the proximal humerus is large, causing extensive bone destruction, does not respond to radiation or chemotherapy, has failed previous surgery or is the only metastatic lesion that is present.
Some of the indications for proximal humerus resection and reconstruction include:
- High-grade and low-grade bone sarcomas
- Soft-tissue sarcomas that invade bone
- Malignant tumors of the proximal humerus
- Primary bone lymphomas
Preparation for Proximal Humerus Resection and Reconstruction
In general, pre-procedure preparation for proximal humerus resection and reconstruction will involve the following steps:
- A thorough examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
- Depending on your medical history, social history, and age, you may need to undergo diagnostic tests such as blood work and imaging to help detect any abnormalities that could threaten the safety of the procedure.
- Diagnostic studies also help determine the extent of bone and soft tissue resection necessary, whether a fracture is present, the proximity of the tumor to vital nerves and vessels, and the dimensions of the prosthesis required.
- You will be asked if you have allergies to medications, anesthesia, or latex.
- You should inform your doctor of any medications, vitamins, or supplements that you are taking.
- You should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
- You should not consume any solids or liquids at least 8 hours prior to surgery.
- Arrange for someone to drive you home after surgery.
- A written consent will be obtained from you after the surgical procedure has been explained in detail.
Procedure for Proximal Humerus Resection and Reconstruction
This is a major procedure that is carried out under general anesthesia. In general, the surgical techniques may involve the following:
- You will lie on the operating table and a long incision is made over the shoulder joint area.
- The underlying muscles are separated to expose the shoulder joint.
- The upper arm bone (humerus) is separated from the glenoid socket of the shoulder bone, and the shoulder socket is inspected.
- Humeral osteotomy is performed with an oscillating saw at the location determined with preoperative imaging. Care is taken to avoid injury to the soft tissues.
- After resection of the proximal humerus, your surgeon will measure the size of the humeral head, the diameter of the medullary canal, and the length of the humerus.
- A trial prosthetic humeral head is then tested. The medullary canal is reamed in order to fit the stem of the prosthesis. The head, neck, and body of the prosthesis are assembled and matched with the resected proximal humerus. It is then fitted in place.
- Range of motion of the shoulder is then tested. If satisfactory, the final prosthesis is then precisely oriented and cemented into the medullary canal.
- Soft-tissue reconstruction is then carried out to cover the prosthesis with muscle tissue. The muscles are positioned and sutured accordingly. Part of the calf muscle (autograft) may be used for minor tissue defects. A graft from a donor (allograft) may be used to cover large tissue defects.
- Joint stability is then checked, surgical drains are placed, and the wound is closed.
Postoperative Care and Instructions
In general, postoperative care instructions and recovery after proximal humerus resection and reconstruction will involve the following steps:
- You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anesthetic reactions and monitor your vital signs as you recover.
- You may need to stay in the hospital for 3 to 4 days before discharge to home.
- You may notice some pain, swelling, and discomfort in the shoulder area. Pain and anti-inflammatory medications are provided as needed.
- Antibiotics are also prescribed to address the risk of surgery-related infection.
- Your arm may be secured with assistive devices such as a sling or a cast for the first few weeks to facilitate healing with instructions on restricted weight-bearing.
- Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
- Refrain from smoking as it can hinder the healing process.
- Refrain from strenuous activities for the first few months and lifting heavy weights for at least 6 months. Gradual increase in activities over a period of time is recommended.
- An individualized physical therapy protocol will be designed to help strengthen shoulder muscles and optimize shoulder function.
- You will be able to resume your normal activities in a month or two after surgery; however, return to sports may take at least 6 months or longer.
- A periodic follow-up appointment will be scheduled to monitor your progress.
Risks and Complications
Proximal humerus resection and reconstruction is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:
- Postoperative pain
- Damage to nerves and vessels
- Shoulder stiffness
- Local tumor recurrence
- Thromboembolism or blood clots
- Anesthetic/allergic reactions