Amputations About the Shoulder: Surgical Considerations

COL Joseph F. Alderete MD

Dr. Alderete or an immediate family member has received research or institutional support from Musculoskeletal Transplant Foundation and serves as a board member, owner, officer, or committee member of Musculoskeletal Transplant Foundation.

ABSTRACT

Proximal upper limb amputations such as those about the shoulder and chest wall are complex procedures requiring a thorough understanding of indications, surgical principles for optimal function, alternative treatments, and rehabilitation techniques to facilitate optimal outcomes. It is helpful to be aware of the limited range of reasons for performing shoulder-level limb ablation and the types of classic and modified methods for performing shoulder disarticulations and forequarter amputations. In some instances, alternative coverage and limb salvage techniques can be used to avoid shoulder-level amputations. Complications are common with these procedures.

Introduction

Shoulder-level amputations are rare. The typical reasons for limb ablation at the shoulder include tumor, trauma, burn (electrical), and infection.¹ With the advent of modern multiagent chemotherapy regimens and advanced surgical techniques, 90% of all neoplasia around the shoulder girdle can be managed with limb salvage.² Nonablative techniques for tumor resection and even limb-threatening infections are usually successful. These resections, with some modification, follow the classic Tikhoff-Linberg procedure for limb salvage. Amputations at the shoulder level involve a glenohumeral disarticulation, forequarter amputation, or ultrahigh transhumeral amputation. Many traditionally planned shoulder disarticulations can be converted to ultrahigh transhumeral amputations with a small part of the humeral head and neck remaining to preserve cosmesis and even motor function with the help of composite free tissue transfer and neuromodulation.³^,⁴ When tumor, trauma, and/or infection prove amenable, such amputations are vastly preferred; therefore, the surgical team contemplating proximal level amputation or advocacy for limb salvage must have in their armamentarium both neuromodulatory tools and methods for extending classic tissue coverage.⁵^,⁶^,⁷^,⁸ In surgical neuromodulation, advanced surgical techniques provide the elements necessary to favor coordinated nerve regeneration providing behavioral adaptation and prevention of painful stimuli.⁹ These surgical neuromodulation techniques encompass the spectrum of true targeted muscle reinnervation (TMR), targeted nerve implantation, regenerative peripheral nerve interface, and guided dessication or “bridge to nowhere” where the nerve is capped and allowed to stop its axonal growth but in an organized fashion.¹⁰ These techniques are necessary for the amputation surgeon to optimize function and are covered in more depth elsewhere in this text.

The forequarter amputation is extremely morbid in terms of body dysmorphism and function. This procedure is reserved for tumors, life-threatening trauma, or infections in which the axillary artery and the brachial plexus have been contaminated or destroyed, or when it is not prudent to leave these two structures in place because of the risk of local recurrence (Figure 1). Most patients treated with forequarter amputation have soft-tissue sarcoma, osteosarcoma, recurrent malignant melanoma, or epidermoid carcinoma.¹¹ This procedure also can be used to treat patients with large, ulcerated, or very painful metastatic carcinomas in whom the tumor often causes extreme pain from plexus radiculopathy.⁵ In these patients, the entire forelimb is removed, in some instance with part of
the chest wall, as well as the scapula, the humerus, and a portion of the clavicle.

FIGURE 1 Magnetic resonance image of a large proximal humeral osteosarcoma with pathologic fracture and soft-tissue extension to the brachial artery and the brachial plexus.

Although there are classic methods for performing these two procedures, the procedure must be tailored to the patient and the corresponding pathophysiology. This often requires modifications to the classic approaches to fit the individual situation. In patients injured by high-energy trauma, amputation about the shoulder can be performed early or late, secondary to the wishes of patients with a flail limb. Early posttraumatic amputations, both shoulder disarticulation and forequarter amputation, are predicated on the amount of viable tissue that is free of contamination. If the tissue around the deltoid is viable, or if local or free tissue transfer is reasonable, an ultrahigh transhumeral amputation combined with shoulder fusion is preferable to removal of the humerus secondary to an intra-articular fracture and distal destruction.²^,¹²^,¹³^,¹⁴^,¹⁵

In keeping with the more classic approaches, several flaps must be maintained, and these determine the surgical technique. First, the ultrashort transhumeral amputation is based on an intact chevron region, which is the skin and muscle of the deltoid region. The ability to bias a chevron-shaped flap of skin, subcutaneous tissue, and full-thickness deltoid muscle to bone makes the ultrashort transhumeral amputation an attractive option. The true shoulder disarticulation can be performed with a lateral chevron region flap, a posterior flap, or an axillary-based flap of durable undersurface tissue. When possible, the axillary flap is preferred because there is no muscle to atrophy over the osseous structures and durable padding is provided for an articulating or a cosmetic prosthesis. The forequarter amputation can be based on a posterior periscapular flap or an anterior pectoralis flap. If neoplasm is an indication for amputation, the absolute necessity to achieve wide margin means that these classic flaps may not be available, so regional rotational or free flaps become essential. The latissimus dorsi rotational flap, either ipsilateral or contralateral, is preferred for defect coverage. Free tissue from the amputated limb is sometimes necessary for coverage if tumor irradiation has been performed.¹⁶^,¹⁷

Alternatives to Amputation

As noted earlier, shoulder-level amputation should be a last resort because 90% of tumor resections and infections can be managed with limb salvage procedures. These limb salvage techniques involve resecting the proximal humerus, the glenoid with or without the main body of the scapula, and the entire or only part of the clavicle. This procedure, which was first described in 1928, is commonly referred to as the Tikhoff-Linberg resection and is the basis for maintaining function and movement in the distal upper limbs while allowing resection of tumor or infection in the shoulder region. The procedure was modified in 1977 by Ralph Marcove to include preservation of the uninvolved scapula despite extensive proximal humeral and glenoid resection.¹⁸^,¹⁹^,²⁰^,²¹ In 1991, Malawar introduced the most useful classification system for shoulder-level deficits and reconstruction. When considering structural loss and replacement or the need to amputate, the author of this chapter finds Malawar’s system to be most user-friendly.¹⁸^,¹⁹^,²⁰ The system was later modified according to a classification from the Musculoskeletal Tumor Society (Figure 2).

The requirements for limb salvage are a free tumor plane adjacent to the axillary neurovascular bundle, the chest wall, or the lymph nodes²²^,²³ or indications in palliative cases where amputation is not justified because of extensive chest wall involvement.¹⁴ After the surgical team understands the defect, it is important to be aware of the goal of achieving a periarticular shoulder reconstruction that can provide a mobile but stable axis for elbow and wrist rotation, which allows placement of the hand in space. Reconstruction can involve the use of allograft, endoprosthesis, fibular autograft, and even pasteurized autograft or combinations of these to provide fusion or an articulating shoulder. Most surgeons who are adept with shoulder resection prefer a stable fusion for a young laborer and a mobile endoprosthetic or allograft prosthetic composite for an older individual.

FIGURE 2 Illustration of the Musculoskeletal Tumor Society classification of skeletal resections about the shoulder girdle. At least one-half of the region must be resected to be so designated. S1 = the blade or spine of the scapula, S2 = the acromion-glenoid cavity complex (the glenoid cavity must be removed), S3 = the proximal epiphysis of the humerus, S4 = the proximal metaphysis of the humerus, and S5 = the proximal part of the diaphysis of the humerus. (Used with permission of Mayo Foundation for Education and Research, all rights reserved.)

Forequarter or Interscapulothoracic Amputation

Indications

The indications for forequarter amputations are soft-tissue sarcoma arising in the axilla beneath the pectoral muscle or the scapula with adherence to the chest wall, osteosarcoma and high-grade chondrosarcoma with extension into the axilla and invading the brachial plexus and the great vessels, and primary tumors arising in the chest wall and involving structures of the thoracic inlet or the axilla.¹²^,¹⁴^,²²^,²³^,²⁴ Case reports of mycosis fungoides illustrate that proximal amputation can be necessary in life-threatening infections of the upper extremity. Palliation of malignant carcinoma, where plexopathy is intolerable, can also be an indication. Finally, trauma and electrical
injury can produce defects and contamination so large that forequarter amputation becomes necessary.¹¹

Technique

Forequarter amputation is the preferred ablative procedure for extensive tumor or infection in which invasion of the brachial plexus, the chest wall, or the axilla makes shoulder disarticulation impossible (Figure 3). This amputation uses anterior-based or posterior-based local flaps. If forequarter amputation is indicated, the flap often is determined by pathology, and the surgical procedure is an adaptation of both anterior-based and posterior-based flaps; however, a bias for one or the other often exists. Most forequarter amputations can be performed by fashioning a posterior skin flap, although an anterior flap is an alternative.¹⁶^,²⁴ The surgical procedure revolves around whether ligation of the subclavian artery and the brachial plexus is managed anteriorly by osteotomy of the clavicle or posteriorly after dividing the muscles from the medial and superior scapula, which facilitates identification of the neurovascular structures through traction and allows ligation from within. The author of this chapter prefers a modification of the two approaches, whereby a posterior full-thickness skin flap is fashioned, but the subclavian vessels and the plexus are managed anteriorly. Before the procedure begins, it should be determined if there is need for free tissue rather than skin graft over viable muscle. This is necessary because the vascularity for a distal filet flap must be preserved when proximal dissection is performed, making subclavian ligation the last step performed before the limb is delivered to the back table.

The patient is positioned in the sloppy lateral decubitus position with a beanbag pliable enough to allow bias anteriorly and posteriorly (by manually tilting the patient over the bag) as the amputation proceeds. If multiple assistants are not available, a limb positioning system often is helpful in keeping the limb elevated and under tension to facilitate dissection (Figure 4).

Incision

Skin flaps are marked along the bony prominence of the clavicle and the scapular spine to allow elevation of the posterior flap from the glenohumeral articulation to the medial border of the scapula. The large teardrop exposure outline begins with an anterior limb that centers on the middle third of the clavicle. The posterior incision traverses the lateral acromion full thickness to fascia overlying the latissimus dorsi, the trapezius, and the infraspinatus. The two incisions meet deep in the axilla based on the patient’s pathophysiology.

Deep Dissection

The sternocleidomastoid and deltoid muscles are elevated off the middle third of the clavicle, and the middle third is osteotomized with a saw. The subclavius muscle is identified and transected to reveal the subclavian artery and the brachial plexus. The subclavian artery is isolated but not ligated if distal harvesting of spare parts will be necessary; otherwise, the author of this chapter controls and quickly ligates the artery and vein and proceeds to nerve identification and transection. Nerve transection is done sharply, but the perineural ends are tagged with polydioxanone suture in the event TMR is an option and to facilitate the placement of intraoperative neural catheters. After the brachial plexus has been ligated, attention is turned to the posterior limb. From the full-thickness skin flap that was created, the medial border of the scapula is identified; an Israel retractor can pull the large posterior flap toward the midline, and a bone hook can be used to put tension on the scapula. The trapezius, rhomboid, and levator muscles are divided to reveal the subscapularis muscle covering the scapula. Next, the medial angle muscles are released from the medial scapula in the following order: the latissimus dorsi and trapezius superficially, followed by the deep rhomboid and levator scapulae muscles. This is best accomplished with a Bovie electrocautery to manage the periscapular plexus. Care is taken to identify and ligate the branches of the transverse cervical and scapular arteries coursing around the scapula. The serratus muscles are then divided by pulling the scapula posterolaterally with a bone hook to reveal the subscapularis and place the forelimb on stretch. After this is complete, there is usually only the need to ligate the suprascapular fossa and the anterior trapezius, which are ligated several centimeters away from the tumor. The axillary incisions are then connected, and the limb is delivered to the back table. The pectoral fascia is sewn to the trapezial and the rhomboid fascia after large suction drains (18 French round or pediatric chest tubes) are placed inferoaxillary and cervicoscapularly, in line with the incisions, with one under the pectoral muscles and one in line with the vertebral dissection. Incisional negative-pressure wound dressings are used, and a large, well-padded circumferential elastic compressive wrap is applied.

Posterior Vascular Isolation With an Anterior Flap

Posterior vascular isolation with an anterior flap is also known as the Littlewood technique.¹⁵ The patient is positioned in a sloppy lateral decubitus position on a beanbag. The clavicle and the scapula are marked, and the clavicle becomes the basis for the skin incisions. First, a full-thickness skin and subcutaneous incision begins along the medial border of the scapula and runs the length of this bone along the superior margin, over the top of the accordion, and finally proceeds distally along the posterolateral acromion. The distal limb is in line with the surgical neck of the scapula and continues distally along the axillary border of the scapula to the distal angle, where the incision is curved medial to a point approximately 5 cm from the midline of the back. Next, the posterior incision is directed anteriorly to meet the anterior incision in the axilla. The anterior incision is then started along the medial border of the clavicle and runs laterally to the deltopectoral groove, where it runs just lateral but in line with this relationship. The skin incision is then curved inferiorly along the pectoral border in the axilla to meet

the posterior axillary incision. The surgeon must carefully create a large full-thickness skin and subcutaneous flap to the fascia, which has been elevated medially off the scapular muscles to 1 cm medial of the medial border of the scapula, and a clavipectoral flap. This flap can include the pectoral muscles if the tumor is biased much posteriorly.

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