Arthroplasty for Shoulder Girdle Tumors



Arthroplasty for Shoulder Girdle Tumors


Cory G. Couch, MD

Thomas W. Wright, MD

C. Parker Gibbs Jr, MD



INTRODUCTION

The treatment goal for malignant shoulder girdle tumors with subsequent reconstruction is complete extirpation of the malignancy and preservation of function. This is accomplished by ensuring adequate surgical margins, preserving vital structures, and subsequently reconstructing bone and soft tissue. Limb-salvage techniques in large shoulder tumors often result in narrow surgical margins due to the intimate relationship to neurovascular structures. Because of the involvement of adjacent soft tissue, proximal humerus resection often results in decreased shoulder function and stability provided by the rotator cuff and capsule, which may then result in dislocation. Despite these challenges, limb salvage can provide considerable functional advantages as well as local tumor control, in contrast to amputation. Restoring function after treating tumors of the shoulder girdle is critical because of the girdle’s role in activities of daily living. When limb salvage is not feasible, amputation is an effective and valuable surgical option.

Although these tumors are infrequent, being knowledgeable of the approach to diagnose and treat them is important to optimizing patient outcomes. Advancements in surgical technique, radiotherapy, chemotherapy, and advanced imaging have led to an estimated 95% of patients being able to undergo limb-salvage surgery for bone or soft tissue sarcomas of the extremity.1

The proximal humerus is the most common site in the upper extremity for primary bone sarcomas and the third most common overall after the distal femur and proximal tibia. A recent Surveillance, Epidemiology, and End Results (SEER) database study by Howlander estimated yearly diagnosis of 3300 bone sarcomas in the United States, with the most common sarcomas being osteosarcoma, Ewing sarcoma, and chondrosarcoma.2 Bone sarcomas of the shoulder girdle typically present with a large extraosseous mass and require resection of a margin of soft tissue covering the tumor to optimize local control.

Proximal humerus metastases, by comparison, are relatively common, with greater than 50% of upper extremity metastasis involving the humerus.3 Treatment for patients with metastases to the shoulder girdle must be a collaborative decision-making effort. In addition to surgical care, radiation oncologists and medical oncologists are crucial parts of the overall treatment of the patient’s disease. Specifically, the extent of surgery and recovery time must be balanced with end-of-life discussions. Each patient is an individual with differing clinical conditions and goals.

For optimal patient survival and functional outcomes, early recognition, accurate diagnosis, and appropriate initial management are the key factors.


HISTORICAL BACKGROUND

Prior to the early to mid-twentieth century, shoulder girdle malignant tumors were treated by forequarter amputation. Early in the twentieth century, a description of the Tikhoff-Linberg interscapulothoracic resection was published, which involved the removal of the head of the humerus, the distal one-third of the clavicle, the scapula, and soft tissue surrounding the sarcoma.4,5,6 This surgical technique and its modifications remain in use today for resections of the shoulder girdle. Although the Tikhoff-Linberg resection was described for scapular resections, this technique is often reported for proximal humerus sarcoma resection. Advancements in imaging modalities, chemotherapy, and radiation have allowed surgeons to better plan and execute surgical resections and perform limb-preservation surgery, while optimizing local control. Advancements in reconstructive techniques and prostheses allow for both an improved variety of options for shoulder reconstruction as well as modest improvements in shoulder function after resection of shoulder girdle tumors.7,8,9


INDICATIONS AND CONTRAINDICATIONS FOR LIMB SALVAGE

Although limb salvage is the preferred treatment for shoulder girdle tumors, approximately 5% of proximal humerus sarcomas do not permit limb salvage. Relative contraindications for limb salvage include tumor encasement of the neurovascular bundle and chest wall invasion. Tumor involvement of the neurovascular bundle must be carefully evaluated when considering limb salvage, as many proximal humerus tumors have a large
extraosseous component that will displace the neurovascular bundle without infiltrating the sheath. If the sheath is infiltrated, then limb salvage with an adequate margin is impossible without segmental resection and reconstruction of the neurovascular structures. If the neurovascular bundle is only displaced and not encased, the sheath around the bundle can be opened and used as a margin in sarcoma resection with preservation of the bundle and limb salvage. This is especially true in instances where effective chemo or radiation therapy is available and employed.

Historically a pathologic fracture through a sarcoma was considered a contraindication to limb-sparing surgery, but advancements in adjuvant therapies have made limb salvage possible in many of these cases. When adequate soft-tissue margins can be maintained around the pathologic fracture without spillage of tumor during resection of the tumor with preservation of a neurovascularly viable limb, salvage is recommended. This is most likely in cases where the fracture has gone on to heal prior to resection. A pathologic fracture in the setting of metastasis to the lung from sarcoma or to the bone from another primary tumor may also not be a contraindication for limb salvage. It is often better to preserve limb function in this patient population to optimize quality of remaining life as resection is not curative.

Most consider extensive invasion of the chest wall by a shoulder girdle tumor to be an absolute contraindication to limb salvage and tumor extension to the chest wall without extensive invasion as only a relative contraindication to limb salvage.10 This recommendation is due to the soft tissue and almost certain neurovascular involvement in the axillary space in shoulder girdle tumors that extensively invade the chest wall and the potentially salvageable neurovascular bundle in tumors that extend to but do not invade the chest wall.


ANATOMIC CONSIDERATIONS

In addition to the need to preserve nerve and vascular function distally, preserving the axillary nerve as it travels just inferior to the glenohumeral joint is essential when planning a reverse total shoulder arthroplasty (RTSA) reconstruction. If the axillary nerve must be sacrificed, then a hemiarthroplasty should be used as a spacer to suspend the limb or a tendon transfer to reconstruct the deltoid moment arm is needed. Often, the axillary nerve cannot be preserved with an adequate margin in pathologic proximal humerus fractures through sarcoma, as the nerve intimately courses around the proximal humerus, innervating the deltoid. It is also vitally important to preserve the musculocutaneous nerve when possible for limb salvage as it courses just medially to the conjoined tendon. Not all branches must be preserved for maintenance of elbow function, and often, the proximal branches must be sacrificed due to the large soft tissue mass expanding into the biceps brachii. Innervation to the brachialis alone can provide adequate elbow flexion strength for a functional elbow as this is the prime elbow flexor; however, supination strength will be diminished with the absence of a functioning biceps.

In metastatic disease to the shoulder girdle, a different approach is taken to margins, preserving function and reconstruction. In patients with diffuse metastatic disease, surgery itself for shoulder girdle tumors is not curative; therefore, a marginal or even intralesional margin is sometimes accepted to optimize both patient recovery speed and function preservation. Often a simpler reconstruction that allows for earlier function is better for patients with metastatic disease as a faster return of function is optimal due to potentially limited survival time of the patient. Although, in patients with oligometastatic disease, in particular, an isolated renal cell metastasis to the shoulder girdle, there is a proven survival benefit for a complete resection.11 Regarding specific tumors, multiple myeloma bone lesions and renal cell carcinoma metastasis should be embolized ideally within 24 hours preoperatively to minimize blood loss in known hypervascular tumors, as preoperative embolization has been shown to reduce estimated blood loss.12

A proximal humerus sarcoma involving the intra-articular glenohumeral joint requires an extra-articular resection for an adequate surgical margin. Presumptive evidence of intra-articular extension includes visualization of the tumor in the glenohumeral joint or glenohumeral effusion on imaging. A study by Ozaki found that assessing the existence of a tumor inside the glenohumeral joint can be difficult in chondrosarcoma and osteosarcoma.13 If the intra-articular glenohumeral joint is determined to have primary sarcoma involvement, an extra-articular resection should be performed. This is not the case for carcinoma metastatic to bone where wide margins are not required. To obtain a wide margin, the capsule and rotator cuff are left intact around the glenohumeral joint, and the glenoid is osteotomized medially to the capsular origin on the glenoid neck. Abdeen et al demonstrated inferior abduction and forward flexion outcomes in extra-articular resections of the humerus.14

In sarcomas arising from the scapula itself, a total or partial scapulectomy may be performed based on the anatomical involvement. If the scapular sarcoma violates the glenohumeral joint, an extra-articular resection of the proximal humerus must be performed en bloc with the scapulectomy, and a Tikhoff-Linberg approach is ideal.


RESECTION CLASSIFICATION

Malawer described an anatomic classification system (FIGURE 48.1) for shoulder girdle tumor resections that include the six categories listed below with subdivisions
of A (intact abductors) and B (abductors partially or completely resected):






Type I: Intra-articular proximal humeral resection

Type II: Partial scapular resection

Type III: Intra-articular total scapulectomy

Type IV: Extra-articular total scapulectomy and humeral head resection (classical Tikhoff-Linberg resection)

Type V: Extra-articular humeral and glenoid resection

Type VI: Extra-articular humeral and total scapular resection10


SHOULDER GIRDLE TUMOR WORK-UP

In patients who present with shoulder girdle tumors, a standardized evaluation approach will expedite diagnosis and aid in treatment planning. Orthogonal radiographs should be the first imaging modality to evaluate a shoulder mass, followed by advanced imaging of the mass with magnetic resonance image (MRI) with and without contrast to include the entire bone. If sarcoma is suspected, then a thin cut noncontrast computed tomography (CT) of the chest is recommended for evaluation of pulmonary metastasis. If metastatic carcinoma, myeloma, or lymphoma is suspected, then a CT of the chest, abdomen, and pelvis is recommended to evaluate for a potential primary source of carcinoma. A whole-body bone scan to evaluate for other sites of potential bone involvement is a recommended workup for all bone tumors. A standardized laboratory panel should also be ordered, including a complete blood count (CBC) with differential, comprehensive metabolic panel (CMP), serum protein electrophoresis (SPEP), and urine protein electrophoresis (UPEP). The next step in diagnosis is a biopsy performed with an appropriate technique either via core needle biopsy or a limited open biopsy.


BIOPSY PRINCIPLES

The recommended biopsy tract for proximal humerus tumors is through the anterior one-third of the deltoid muscle belly. It is not recommended to contaminate
the pectoralis major with a biopsy through the deltopectoral interval due to the increased risk of hematoma formation and spread to neurovascular structures and the chest wall. The biopsy through the anterior one-third deltoid should be performed using a longitudinal incision of approximately 1 to 2 cm just lateral to the deltopectoral interval. The biopsy tract should be extra-articular, only involving the deltoid and the proximal humerus lateral to the bicipital groove, with the level of the biopsy based over the center portion of the tumor as long as the previously stated principles are not violated. Minimizing traumatic dissection and meticulous hemostasis during the biopsy is critical to minimize bleeding and thus contamination of surrounding soft tissues and the subacromial space.


INCISION/APPROACH OPTIONS


Tikhoff-Linberg Approach

In shoulder girdle tumors that involve the proximal humerus and for which resection with a margin involves resecting the deltoid, acromion, glenoid, and distal clavicle, a Tikhoff-Linberg approach provides extensile exposure. This approach is reserved for patients for whom a deltopectoral or deltoid splitting approach will not provide enough exposure for adequate margins in resection. With this approach, the recommended reconstructive option is an endoprosthesis anchored to the remaining scapula or a resection arthroplasty with the remaining humerus anchored to the scapula or clavicle. The goal is for the patient to maintain elbow and hand function; no shoulder function is expected apart from some scapulothoracic motion. It is possible to power a shoulder arthroplasty with the described tendon transfers when the deltoid is sacrificed, but this is beyond the scope of this chapter. The Tikhoff-Linberg approach and exposure is demonstrated in FIGURE 48.2.

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Jun 23, 2022 | Posted by in ORTHOPEDIC | Comments Off on Arthroplasty for Shoulder Girdle Tumors

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