BACKGROUND

 

 

The humerus is a common site of metastatic bone disease requiring surgery. A metastasis at that site, and especially one involving the dominant extremity, has an immediate and profound impact on the affected individual's ability to perform activities of daily living. The quality of surgery, therefore, is an important determinant in restoring vital function.

 

A detailed preoperative clinical and imaging evaluation is mandatory for defining the morphologic characteristics of the lesion and, in turn, establishing the indication for surgical intervention as well as distinguishing between lesions that can be managed with curettage and cemented fixation and those which

require resection with endoprosthetic reconstruction.2,3,5,6

 

Unlike primary sarcomas of the humerus, metastatic tumors usually have a small soft tissue component, even in the presence of extensive bone destruction. This characteristic allows resection of bony elements only and the sparing of the extracortical structures, such as the joint capsule, overlying muscles, and muscle attachments, and affords the opportunity for using them to reconstruct and preserve function (FIG 1). To this end, exposure of the proximal humerus is done by splitting the deltoid muscle rather than using the deltopectoral interval, as is done in the case of a primary sarcoma of bone, which necessitates en bloc resection of the deltoid muscle with the tumor. Moreover, a few centimeters of upper limb shortening following resection of bone segment has minimal impact on function because a slight difference in positioning of that extremity in space can easily compensate for such limb length discrepancy.

 

 

 

FIG 1 • A. Primary bone sarcomas usually have considerable extension into the soft tissues. Resection of such tumors at the proximal humerus would require en bloc removal of the overlying deltoid muscle, rotator cuff tendons, and the joint capsule. B. Bone metastases, however, usually present with less soft tissue involvement, and their resection involves removal of bony elements with only a thin layer of surrounding soft tissues.

 

 

In contrast, a similar discrepancy in the lower extremities that require almost equal length for normal gait would result in an inevitable limp, the extent of which would be proportional to the shortening of the operated

extremity.2

 

Because of different anatomic and surgical considerations, surgeries around the proximal humerus (type I), humeral diaphysis (type II), and distal humerus (type III) will be discussed separately (FIG 2).1

ANATOMY

 

Proximal humerus: type I metastasis

 

 

Covered anteriorly and laterally by the deltoid muscle

 

Joint capsule encircles the humeral head and attaches to the base of anatomic neck.

 

Attachment site for the rotator cuff muscles. Long head of the biceps muscle crosses the anterior aspect within the bicipital groove.

 

Humeral diaphysis: type II metastasis

 

Upper half is occupied by muscle insertions:

 

 

 

Medial aspect—teres major, latissimus dorsi, coracobrachialis Lateral aspect—pectoralis major, deltoid

 

P.128

 

 

 

 

FIG 2 • Illustrations and plain radiographs showing a type I humeral metastasis (A,B) extending across the anatomic neck to the humeral head, a type II humeral metastasis (C,D) involving the humeral diaphysis between the anatomic neck and the supracondylar ridges of the humerus, and a type III humeral metastasis (E,F) extending to the humeral condyles below the supracondylar ridges.

 

 

 

Radial nerve curves at the back from medial to lateral at the midarm level Lower half is occupied by muscle origins:

 

 

Medial aspect—brachialis Lateral aspect—brachioradialis

 

 

Neurovascular bundle along its medial aspect Distal humerus: type III metastasis

 

Neurovascular bundle along its medial aspect between the biceps and brachialis muscles

Radial nerve along its lateral aspect between the brachialis and brachioradialis muscles

INDICATIONS

Pathologic fracture Impending pathologic fracture

Intractable pain associated with locally progressive disease that had shown inadequate response to narcotics and preoperative radiation therapy

Solitary bone metastasis in selected patients

 

 

IMAGING AND OTHER STAGING STUDIES

 

Plain radiographs of the entire humerus are mandatory to rule out synchronous metastases that may change the extent and technique of surgery. Computed tomography of the lesion will clearly define the extents of bone destruction and soft tissue component. Total body bone scintigraphy is done to detect synchronous metastases elsewhere in the skeleton. At the conclusion of imaging, the surgeon should be able to answer the following questions:

 

Are there additional humeral metastases and, if there are, can they be managed by nonoperative techniques or do they require surgery?

 

Are there additional skeletal metastases and, if there are, can they be managed by nonoperative techniques or do they require surgery?

 

What is the appropriate surgery? As a rule, the tumor curettage and cemented fixation approach is used for lesions in which the remaining cortices allow containment of the fixation device; otherwise, surgery involves resection of the affected bone segment with prosthetic reconstruction.

 

 

P.129

 

TECHNIQUES

• Types I and II Metastases

Position and Incision

The patient is placed in a semilateral position, and an anterior utilitarian shoulder girdle incision is made.

The incision begins at the junction of the inner and middle third of the clavicle and continues over the coracoid process, along the deltopectoral groove, and down the arm over the medial border of the biceps muscle (TECH FIG 1).

 

 

 

 

TECH FIG 1 • A,B. The utilitarian shoulder incision is used for exposure of types I and II metastases. It begins at the junction of the inner and middle third of the clavicle and continues over the coracoid process, along the deltopectoral groove, and down the arm over the medial border of the biceps muscle up to the distal arm, if required.

 

 

 

TECH FIG 2 • A,B. The deltoid and brachialis muscles are divided longitudinally to expose the humeral head and humeral diaphysis. The periosteum is similarly divided and reflected with muscle to expose the

underlying cortex.

 

Exposure

 

The deltoid muscle is divided longitudinally to expose the humeral head and proximal third of the humeral diaphysis.

 

Exposure of the remaining diaphysis is achieved by similarly dividing the brachialis muscle.

 

Electrocautery and rasps are used to detach and reflect the periosteum and muscle attachments from the underlying cortex (TECH FIG 2).

 

P.130

Tumor Removal

Type I Metastasis

 

Using electrocautery, the rotator cuff tendons are detached from the humerus, the long head of the biceps is cut at its insertion site around the glenoid, and the joint capsule is opened.

 

Osteotomy is carried out at the required level below the surgical neck, 1 to 2 cm below the distal margin of the tumor, and the proximal humerus can now be removed (TECH FIG 3).

Type II Metastasis

 

A longitudinal cortical window with oval edges is made just above the lesion (TECH FIG 4A).

 

Gross tumor is removed with hand curettes (TECH FIG 4B,C). Curettage should be meticulous and leave only microscopic disease in the tumor cavity.

 

It is followed by high-speed burr drilling of walls of the tumor cavity (TECH FIG 4D-F).

 

Occasionally, the cortices of the involved segment are completely destroyed, leaving no option but an intercalary resection of the affected segment. This is achieved by an osteotomy 1 to 2 cm above and below the segment (TECH FIG 4G-I).

Mechanical Reconstruction

Type I Metastasis

 

A cemented tumor prosthesis is used for reconstruction (TECH FIG 5). The prosthetic design should allow the reattachment of rotator cuff tendons.

 

 

 

TECH FIG 3 • A-C. Resection of the type I metastatic renal cell carcinoma in the plain radiograph in FIG 2B is executed by detaching the rotator cuff tendons and the long head of the biceps and opening the joint capsule. An osteotomy is performed, and the proximal humeral segment is removed. D. Surgical specimen.

Type II Metastasis

 

An intramedullary nail is introduced.

 

After proper position and length are verified, the nail is partially pulled back, and the entire tumor cavity is filled with cement (TECH FIG 6A,B). The nail is then pushed back into the medullary canal and fixed with interlocking screws.

 

Alternatively, a side plate can be used for reinforcement (TECH FIG 6C,D).

 

If an intercalary resection had been done, the remaining bone defect is filled with cement (TECH FIG 6E-G).

Soft Tissue Reconstruction and Wound Closure

Type I Metastasis

 

The rotator cuff tendons are attached to the prosthetic head using 3-mm Dacron tapes (Deknatel, Falls River, MA) or no. 5 Ethibond sutures (Ethicon, Somerville, NJ) (TECH FIG 7).

 

The pectoralis major, teres major, latissimus dorsi, and coracobrachialis are similarly attached.

 

Using the same technique, the prosthetic head is also secured to the drill holes within the bony elements around the shoulder joint, acromion, clavicle, and glenoid.

 

The second, overlying muscular layer includes the deltoid and brachialis muscles, which are sutured to cover the implant.

Type II Metastasis

 

The deltoid and brachialis muscles are sutured to cover the humeral diaphysis.

 

 

P.131

 

 

 

 

TECH FIG 4 • A. A longitudinal cortical window with oval edges is made just above the lesion. B,C. Gross tumor is removed with hand curettes. Curettage should be meticulous and leave only microscopic disease in the tumor cavity. (continued)

 

 

P.132

 

 

 

TECH FIG 4 • (continued) D,E. Curettage is followed by high-speed burr drilling of walls of the tumor cavity.

F. Tumor cavity following curettage and burr drilling G. Plain radiograph of type II thyroid carcinoma metastases. The extent of cortical destruction does not allow curettage and burr drilling and so intercalary resection of the affected segment is indicated. H-I. Intercalary resection is achieved by proximal and distal osteotomies 1 to 2 cm above and below the tumor margin.

 

 

P.133

 

 

 

TECH FIG 5 • Intraoperative photograph (A) and plain radiograph (B) showing a proximal humeral tumor prosthesis used for reconstruction after resection of a type I metastasis.

 

 

 

TECH FIG 6 • A. An intramedullary nail is introduced. B. After proper position and length are verified, the nail is partially pulled back, and the entire tumor cavity is filled with cement. The nail is then pushed back into the medullary canal and fixed with interlocking screws. Intraoperative photograph (C) and plain

radiograph (D) showing side plate reinforcement of a cemented intramedullary humeral nail. Intraoperative photographs (E,F) and plain radiograph (G) showing side plate reinforcement of a cemented intramedullary humeral nail following intercalary resection of a type II metastasis. The remaining bone defect is filled with cement. (continued)

 

 

P.134

 

 

 

 

TECH FIG 6 • (continued)

 

 

 

TECH FIG 7 • A. Three-millimeter Dacron tapes or (B) no. 5 Ethibond sutures are used for securing the prosthetic head to the neighboring acromion, clavicle, and glenoid and for reattachment of the rotator cuff tendons. C. Rotator cuff tendons are sutured to the prosthetic head.

 

 

 

• Type III Metastasis

P.135

 

These tumors extend to the humeral condyles below the supracondylar ridges. In most of these cases, the extent of bone destruction allows tumor curettage and reconstruction with cemented hardware (the technique will be described in the following section). Rarely will extensive destruction of the distal humerus necessitate formal resection with endoprosthetic reconstruction.

Position and Incision

 

The patient is placed supine on the operating table with the ipsilateral arm lying across the chest. A slightly curved incision is made on the lateral aspect of the arm over the supracondylar ridge of the elbow (TECH FIG 8).

 

 

 

TECH FIG 8 • To expose a lesion at the distal humerus, the patient is placed supine on the operating table with the ipsilateral arm lying across the chest. A slightly curved incision is made on the lateral aspect of the arm over the supracondylar ridge of the elbow.

 

 

 

TECH FIG 9 • The distal humerus and radial head are exposed using the plane between the brachioradialis and triceps muscles.

 

 

 

TECH FIG 10 • A. Gross tumor is removed with hand curettes. B. Curettage is followed by high-speed burr drilling.

Exposure

 

The distal humerus is exposed using the plane between the brachioradialis and triceps muscles. The brachioradialis is reflected anteriorly and the triceps posteriorly. Further posterior reflection of the anconeus muscle combined with detachment and anterior reflection of the common extensor origin exposes the radial head (TECH FIG 9).

Tumor Removal

 

A longitudinal cortical window with oval edges is made just above the lesion. Gross tumor is removed with hand curettes (TECH FIG 10A), and this is followed by high-speed burr drilling (TECH FIG 10B).

 

P.136

Mechanical Reconstruction

 

An intramedullary rod is introduced through the tumor cavity, which is then filled with cement. A

reconstruction plate along the lateral supracondylar ridge is used to reinforce the reconstruction (TECH FIG 11).

 

 

 

TECH FIG 11 • A cemented intramedullary rod that is reinforced by a reconstruction plate along the supracondylar ridge is used for reconstruction.

Wound Closure

 

The wound is closed over suction drains.

 

Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed.

 

 

 

PEARLS AND PITFALLS

Type II

metastasis

• Adequate imaging of the entire humerus—decision on tumor curettage, intercalary resection, or resection with

  endoprosthetic reconstruction

   

• Use the utilitarian shoulder incision.

   

• Wide exposure of the tumor cavity using properly positioned and large cortical window

   

• Meticulous curettage and burr drilling

   

• Reconstruction with cemented hardware

   

• If endoprosthetic reconstruction was done

   

  • Secure the prosthetic head to the surrounding bony elements to ensure shoulder stability.

     

  • Reattach the rotator cuff tendons to the prosthetic head to allow shoulder function.

     

  • Immobilize the shoulder for 3 weeks and only then allow ROM exercises.

Type III

metastasis

• Adequate exposure of the distal humerus

• Meticulous curettage and burr drilling

   

• Reconstruction with cemented hardware

   

• Early postoperative mobilization of the elbow joint

 

 

POSTOPERATIVE CARE AND REHABILITATION

Types I and II Metastases

 

Continuous suction is required for 3 to 5 days, and perioperative intravenous antibiotics are continued until the drainage tubes are removed.

 

If endoprosthetic reconstruction had been done, the shoulder is immobilized in a sling for 3 weeks. During that time, the rehabilitation program emphasizes range of motion (ROM) of the elbow, wrist, and fingers with gravity assistance. Gradual passive and active ROM of the shoulder is then started, with emphasis on forward flexion, abduction, and shrugging.

 

If tumor curettage had been carried out, ROM exercises should be practiced without delay. Upon wound healing, usually 3 to 4 weeks after surgery, patients are referred to adjuvant radiation therapy. Radiation therapy is usually not required in patients who had undergone proximal humerus resection with endoprosthetic reconstruction.

 

 

P.137

Type III Metastasis

 

 

Passive and active ROM exercises of the elbow joint are initiated when the suction drains are removed. Upon wound healing, usually 3 to 4 weeks after surgery, the patients are referred to adjuvant radiation

therapy. Radiation therapy is usually not required for patients who had undergone distal humerus resection with endoprosthetic reconstruction.

OUTCOMES

Most patients who undergo resection of a humeral metastasis experience immediate relief of their metastasis-related pain. Patients who had a type II metastasis and who underwent either curettage or intercalary resection have better ROMs and superior functional outcome than the ones who underwent proximal or distal humeral resection with endoprosthetic reconstruction.

Bickels et al2 reported that overall total function in their 56 patients (95%) who had undergone resection of a humeral metastasis was greater than 68% of full normal upper extremity function, which is the mean

functional outcome score after reconstruction of the upper extremity.4

 

 

COMPLICATIONS

Thromboembolic complications, deep wound infections, and prosthetic loosening (rare)

Proximal humeral prosthetic dislocation (poor securing to the adjacent bones and inadequate soft tissue coverage)

Decreased ROM around the shoulder (poor attachment of the rotator cuff tendons to the prosthesis) Decreased elbow ROM after surgery around distal humerus lesions

Local tumor recurrence of less than 5% if adjuvant tumor removal was done adequately and adjuvant radiation therapy had been administered.

 

 

REFERENCES

1. Bickels J, Kollender Y, Wittig JC, et al. Function after resection of humeral metastases. Analysis of 59 consecutive patients. Clin Orthop Relat Res 2005;137:201-208.

    

    

2. Bickels J, Wittig JC, Kollender Y, et al. Limb-sparing resections of the shoulder girdle. J Am Coll Surg 2002;194:422-435.

    

    

3. Eckardt JJ, Kabo JM, Kelly CM, et al. Endoprosthetic reconstructions for bone metastases. Clin Orthop Relat Res 2003;415(suppl):s254-s262.

    

    

4. Enneking WF, Dunham W, Gebhardt MC, et al. A system for functional evaluation of reconstructive procedures after surgical treatment of tumors of the musculoskeletal system. Clin Orthop Relat Res 1993;286:241-246.

    

    

5. Flemming JE, Beals RK. Pathologic fractures of the humerus. Clin Orthop 1986;203:258-260.

    

    

6. Harrington KD, Sim FH, Enis JE, et al. Methylmethacrylate as an adjuvant in internal fixation of pathological fractures: experience with three hundred and seventy-five cases. J Bone Joint Surg 1976;58A:1047-1055.