Mastering Shoulder Girdle Resections: An Intraoperative Guide to Limb-Sparing Oncologic Surgery

Introduction and Epidemiology

The management of primary bone and soft tissue neoplasms of the shoulder girdle represents one of the most complex challenges in orthopedic oncology. Although the upper extremity is affected by bone and soft tissue sarcomas only one-third as often as the lower extremity, the scapula and proximal humerus remain classic anatomic predilections for primary malignancies. In the pediatric and adolescent populations, osteosarcoma and Ewing sarcoma predominate, whereas chondrosarcoma and undifferentiated pleomorphic sarcoma are more frequently encountered in adults. Furthermore, the proximal humerus is a highly favored site for metastatic disease, particularly from hypernephroma (renal cell carcinoma), breast, lung, thyroid, and prostate carcinomas.

Historically, until the mid-20th century, the standard of care for malignant tumors of the shoulder girdle was the forequarter amputation. The paradigm shifted significantly with the evolution of limb-sparing techniques. Early limb-sparing concepts date back to Liston’s partial scapulectomy in 1819 and the pioneering interscapulothoracic resections described by Pranishkov (1908), Baumann (1914), and Linberg (1926)—collectively culminating in the classic Tikhoff-Linberg procedure.

While initially reserved for low-grade or benign aggressive lesions, Marcove et al. (1977) revolutionized the field by successfully applying en bloc extra-articular resections to high-grade spindle cell sarcomas of the proximal humerus. Today, with the advent of neoadjuvant chemotherapy, advanced cross-sectional imaging, and modular endoprosthetics, approximately 95% of patients with shoulder girdle sarcomas can be safely treated with limb-sparing resections without compromising oncologic survival.

The bimodal distribution of primary bone tumors requires a nuanced understanding of tumor biology. Osteosarcoma typically presents in the second decade of life, heavily favoring the metaphysis of the proximal humerus. Ewing sarcoma, driven by the characteristic t(11;22) chromosomal translocation, frequently involves the diaphysis and exhibits aggressive permeative bone destruction with a large soft tissue mass. In contrast, primary chondrosarcoma of the shoulder girdle generally affects adults in their fourth to sixth decades, often arising from a preexisting osteochondroma in the proximal humerus or scapula. Because chondrosarcoma is largely resistant to chemotherapy and radiotherapy, wide surgical resection remains the sole definitive treatment, placing immense importance on precise preoperative planning and flawless surgical execution.

Understanding the epidemiology of these lesions is critical for formulating an appropriate differential diagnosis. The proximal humerus is the third most common site for primary osteosarcoma, following the distal femur and proximal tibia. Soft tissue sarcomas of the shoulder girdle, such as synovial sarcoma, liposarcoma, and myxofibrosarcoma, often present as painless, deep-seated masses that are frequently misdiagnosed as benign lipomas, hematomas, or muscle strains, leading to delayed diagnosis or inadvertent "whoops" excisions.

The integration of multidisciplinary tumor boards has become the standard of care. The coordination between orthopedic oncologists, medical oncologists, radiation oncologists, musculoskeletal radiologists, and pathologists ensures that systemic control is achieved alongside local tumor eradication. For instance, the utilization of MAP chemotherapy (methotrexate, doxorubicin, and cisplatin) has dramatically improved the 5-year survival rate of localized osteosarcoma from less than 20% in the era of amputation alone to approximately 70% today.

Surgical Anatomy and Biomechanics

The Shoulder Girdle and the Axillary Space

The shoulder girdle comprises the proximal humerus, the scapula, the distal third of the clavicle, and the complex investing musculofascial envelope. Primary soft tissue sarcomas favor the shoulder girdle and may secondarily invade the underlying osseous structures, necessitating composite resections.

The axilla represents a uniquely silent anatomic space. Tumors arising within or metastasizing to the axillary lymph nodes can grow to massive dimensions before becoming clinically symptomatic. The boundaries of the axilla dictate the surgical approach and the potential for neurovascular involvement. Anteriorly, the axilla is bounded by the pectoralis major and minor muscles; posteriorly by the latissimus dorsi, teres major, and subscapularis; medially by the serratus anterior and the thoracic wall; and laterally by the intertubercular sulcus of the humerus.

The axillary artery and the brachial plexus cords form the critical neurovascular bundle traversing this space. The relationship of the tumor to the neurovascular bundle is the primary determinant of limb salvage feasibility. The axillary artery is divided into three parts by the pectoralis minor muscle, providing key branches such as the superior thoracic, thoracoacromial, lateral thoracic, subscapular, and the anterior and posterior circumflex humeral arteries. The subscapular artery and its circumflex scapular branch are of paramount importance when considering pedicled latissimus dorsi flaps for soft tissue coverage following massive resections.

Neurovascular Proximity and Compartmental Margins

Unlike the thigh, where distinct fascial compartments allow for straightforward compartmental resections, the shoulder girdle lacks robust fascial boundaries. The deltoid, rotator cuff, and periscapular muscles are separated by relatively thin epimysium, allowing aggressive sarcomas to easily transgress muscular boundaries. The axillary nerve, traversing the quadrangular space alongside the posterior circumflex humeral artery, is frequently at risk or directly involved by tumors of the proximal humerus. Resection of the axillary nerve results in profound deltoid paralysis, fundamentally altering the reconstructive strategy and postoperative functional expectations.

The brachial plexus, emerging from the scalene triangle and passing beneath the clavicle, lies in intimate proximity to the medial aspect of the coracoid process and the subscapularis muscle. High-grade sarcomas of the coracoid or the medial scapular neck may encase the cords of the brachial plexus. Preoperative MRI evaluation must meticulously assess the fat planes between the tumor pseudocapsule and the epineurium of the plexus. Loss of this fat plane suggests perineural invasion, which may necessitate epineural dissection or, in severe cases, forequarter amputation to achieve clear oncologic margins.

Biomechanical Considerations in Reconstruction

The glenohumeral joint is inherently unstable, relying heavily on the dynamic stabilization provided by the rotator cuff and the static stabilization of the capsulolabral complex. Resection of the proximal humerus for a primary bone sarcoma typically mandates the excision of the rotator cuff insertions on the greater and lesser tuberosities, as well as the joint capsule (extra-articular resection).

Consequently, traditional anatomic endoprosthetic reconstructions function primarily as passive spacers. Active forward elevation and abduction are severely compromised, and the primary biomechanical goal shifts from restoring full range of motion to providing a stable fulcrum for hand and elbow function. The advent of reverse total shoulder arthroplasty (RTSA) implants modified for oncology has provided a biomechanical advantage by medializing the center of rotation and increasing the deltoid moment arm. However, the application of RTSA in oncology is strictly predicated on the preservation of a functional axillary nerve and adequate deltoid musculature.

Indications and Contraindications

The decision algorithm for limb-sparing surgery versus amputation in the upper extremity is governed by the ability to achieve wide oncologic margins while preserving a limb that is more functional than a prosthesis. Given the highly specialized nature of upper extremity prosthetics and their generally poor functional acceptance rates compared to lower extremity prostheses, limb salvage is pursued aggressively whenever oncologically sound.

Absolute contraindications to limb salvage include major neurovascular encasement that precludes a functional distal extremity following resection. Specifically, complete encasement of the brachial plexus or the axillary/brachial artery where vascular bypass is not feasible or would result in an ischemic, insensate, and flail limb necessitates forequarter amputation.

Relative contraindications include massive soft tissue extension that prevents adequate soft tissue coverage, pathological fractures with extensive hematoma tracking through multiple compartments, and severe radiation-induced tissue necrosis. Pathological fractures were historically considered an absolute contraindication to limb salvage; however, contemporary studies have demonstrated that with meticulous resection of the fracture hematoma and en bloc excision of the involved compartments, limb salvage can be achieved with local recurrence rates comparable to those of non-fractured cases.

Pre Operative Planning and Patient Positioning

Advanced Imaging and Staging

Meticulous preoperative planning begins with comprehensive local and systemic staging. Magnetic Resonance Imaging (MRI) of the entire humerus and shoulder girdle, utilizing T1-weighted, T2-weighted fat-suppressed, and post-contrast sequences, is the gold standard for defining intraosseous tumor extent (skip metastases) and extraosseous soft tissue extension. The relationship of the tumor pseudocapsule to the axillary nerve, radial nerve, and axillary vessels must be scrutinized.

Computed Tomography (CT) of the shoulder provides critical information regarding cortical destruction, matrix mineralization (e.g., rings and arcs of chondrosarcoma, osteoid production in osteosarcoma), and glenoid bone stock. For patients undergoing custom endoprosthetic reconstruction or massive allograft-prosthetic composites, 3D CT reconstructions are utilized for computer-aided design and manufacturing (CAD/CAM) of patient-specific cutting guides (PSI). Systemic staging typically involves a high-resolution CT of the chest to rule out pulmonary metastases, and a whole-body PET/CT or Technetium-99m bone scan to evaluate for distant osseous lesions.

Biopsy Principles

The biopsy is a critical step that dictates the ultimate surgical approach. An improperly placed biopsy tract can compromise limb salvage and necessitate amputation. The biopsy must be performed by the treating orthopedic oncologist or a musculoskeletal radiologist in direct consultation with the surgeon. The tract must be placed longitudinally, directly in line with the planned definitive surgical incision (typically the deltopectoral approach). Transverse incisions or approaches through uninvolved muscle compartments (e.g., a posterior approach for an anteriorly based tumor) are strictly prohibited. Meticulous hemostasis is required to prevent a contaminated hematoma.

Virtual Surgical Planning and Implant Selection

Virtual Surgical Planning (VSP) has revolutionized the precision of limb-sparing resections. By fusing CT and MRI data, the surgeon can virtually define the tumor margins (typically 2-3 cm for high-grade bone sarcomas) and design the osteotomy planes. Endoprosthetic selection depends on the extent of the resection. Malawer classified shoulder girdle resections into six types:
* Type I: Intra-articular proximal humerus resection.
* Type II: Partial scapulectomy.
* Type III: Intra-articular total scapulectomy.
* Type IV: Extra-articular total scapulectomy.
* Type V: Extra-articular proximal humerus and glenoid resection (Tikhoff-Linberg).
* Type VI: Extra-articular total humerus and total scapula resection.

For a standard Type I resection, a modular proximal humeral replacement is utilized. If the abductor mechanism can be salvaged, an oncologic reverse total shoulder arthroplasty may be indicated to optimize forward elevation. If the deltoid and rotator cuff are entirely sacrificed, a hemiarthroplasty with soft tissue suspension (e.g., using a Trevira tube or LARS ligament) is preferred to minimize the risk of dislocation.

Patient Positioning and Draping

The patient is typically positioned in a modified beach chair or semi-lateral decubitus position, depending on the posterior extent of the tumor. The beach chair position allows excellent access to the anterior shoulder, axilla, and proximal humerus, while the lateral decubitus position provides superior access to the scapula.

A beanbag positioner is utilized to secure the torso. The entire forequarter, from the sternal notch medially to the inferior angle of the scapula posteriorly, and down to the fingertips, must be prepped and draped free. An impervious stockinette is used to wrap the distal arm and hand. A sterile tourniquet is not feasible for proximal humerus or scapular resections; therefore, meticulous surgical technique and hypotensive anesthesia are critical for minimizing blood loss. Cell salvage systems (e.g., Cell Saver) are generally contraindicated in the resection of malignant tumors due to the theoretical risk of disseminating circulating tumor cells, though they may be used in selected benign aggressive lesions or with specialized leukocyte depletion filters.

Detailed Surgical Approach and Technique

Incision and Biopsy Tract Excision

The standard utilitarian approach for a proximal humerus resection is an extended deltopectoral incision. The incision begins at the lateral third of the clavicle, passes over the coracoid process, and extends distally along the deltopectoral groove, following the anterolateral border of the humerus.

The previous biopsy tract must be incorporated into the incision as an elliptical island of skin and subcutaneous tissue. This tract is left attached to the underlying muscle and resected en bloc with the tumor specimen. Flaps are raised medially to expose the pectoralis major and laterally to expose the deltoid.

Deltopectoral Interval and Anterior Dissection

The cephalic vein is identified and typically retracted laterally with the deltoid to preserve its venous drainage, although it may be ligated if involved by the tumor. The deltopectoral interval is developed. If the tumor has anterior extraosseous extension infiltrating the deltoid, a cuff of normal deltoid muscle must be left attached to the tumor to ensure a wide margin.

The insertion of the pectoralis major on the lateral lip of the bicipital groove is identified. If the tumor extends distally, the pectoralis major tendon is transected near its insertion and tagged for later reconstruction. The clavipectoral fascia is incised, exposing the conjoined tendon (short head of the biceps and coracobrachialis) originating from the coracoid process.

Neurovascular Identification and Mobilization

Safe mobilization of the neurovascular bundle is the most critical and technically demanding aspect of the procedure. The conjoined tendon is retracted medially, bringing the axillary sheath into view. The musculocutaneous nerve is identified entering the coracobrachialis and protected. The axillary artery and vein are isolated.

The anterior and posterior circumflex humeral vessels are identified as they wrap around the surgical neck of the humerus. These vessels are typically ligated and divided to allow the neurovascular bundle to fall away medially. The axillary nerve is identified as it dives posteriorly through the quadrangular space. If the tumor involves the surgical neck or proximal metaphysis with posterior extension, the axillary nerve must be carefully dissected free. If it is encased by the tumor, it must be sacrificed, resulting in definitive deltoid denervation. The radial nerve is identified in the spiral groove posteriorly and protected during the distal dissection and osteotomy.

Osteotomy and Tumor Resection

Once the neurovascular bundle is safely retracted, the distal extent of the tumor is addressed. Based on preoperative MRI measurements, the planned osteotomy site is marked on the humeral diaphysis, ensuring a minimum of 2 to 3 cm of normal marrow margin. The periosteum is incised circumferentially. Hohmann retractors are placed carefully to protect the radial nerve posteriorly.

The osteotomy is performed using an oscillating saw. A marrow sample from the distal stump is immediately sent for frozen section analysis to confirm clear osseous margins. The proximal humerus is then manipulated to facilitate the intra-articular or extra-articular resection.

For an intra-articular resection (Type I), the joint capsule is incised, and the rotator cuff tendons (supraspinatus, infraspinatus, teres minor, subscapularis) are transected near their insertions. The long head of the biceps is tenotomized. The specimen is delivered en bloc.

For an extra-articular resection (Type V), the glenoid and the entire joint capsule must be resected intact with the proximal humerus. This requires osteotomies of the coracoid process, the acromion, and the scapular neck, utilizing a Gigli saw or osteotomes, ensuring the joint remains unopened to prevent tumor spillage.

Endoprosthetic Reconstruction and Soft Tissue Coverage

Following copious irrigation of the tumor bed, reconstruction commences. The distal humeral canal is sequentially reamed to accommodate the endoprosthetic stem. Modular components are assembled to match the exact length of the resected bone, maintaining appropriate soft tissue tension. The stem is typically cemented using polymethylmethacrylate (PMMA) loaded with antibiotics, although press-fit stems with porous ingrowth collars are utilized in younger patients with

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