What is the step by step procedure for the surgical excision of an osteochondroma of the left humerus?

Surgical Excision of Osteochondroma of Left Humerus: Step-by-Step Procedure

The surgical excision of an osteochondroma of the left humerus should be performed with wide excision and negative surgical margins to minimize local recurrence while preserving limb function. 1

Preoperative Assessment and Planning

1. Imaging Studies:

   • Plain radiographs of the left humerus (AP and lateral views)
   • MRI of the left humerus to define tumor extent and relationship to neurovascular structures
   • CT scan to assess cortical and medullary continuity with parent bone
   • Chest imaging (radiograph or CT) to rule out pulmonary metastases
   • Bone scan to rule out skip lesions 1

2. Biopsy:

   • If not already performed, a biopsy should be planned along the same incision line that will be used for definitive surgery
   • Collaboration between surgeon, musculoskeletal oncologist, and bone pathologist is critical 1
   • Core needle biopsy is preferred if adequate tissue can be obtained 1

Surgical Procedure

1. Patient Positioning and Preparation

• Position patient supine with arm abducted on a radiolucent table
• Prepare and drape the entire left upper extremity and shoulder
• Apply tourniquet (if feasible based on tumor location)

2. Incision and Approach

• Plan incision directly over the osteochondroma, incorporating previous biopsy tract if present
• Make a longitudinal incision along the lateral or anterior aspect of the humerus depending on tumor location
• Carefully dissect through subcutaneous tissue and fascia
• Identify and protect major neurovascular structures (particularly the radial, median, and ulnar nerves) 2

3. Tumor Exposure

• Identify the osteochondroma and its stalk/base
• Carefully dissect soft tissues around the tumor
• Expose the entire lesion including the cartilaginous cap
• Identify the junction between normal bone and tumor base

4. Tumor Excision

• Perform an extraperiosteal en bloc resection 3
• For pedunculated osteochondromas:
  • Excise the lesion at its base using an oscillating saw or osteotome
  • Remove the entire cartilaginous cap
• For sessile osteochondromas:
  • Mark the junction between normal bone and tumor
  • Use high-speed burr or oscillating saw to remove the lesion with a margin of normal bone
• Ensure complete removal of the cartilaginous cap to prevent recurrence 4

5. Bone Bed Preparation

• Smooth the bone surface with a high-speed burr
• Remove any remaining cartilage tissue
• Irrigate thoroughly to remove bone debris

6. Hemostasis and Closure

• Achieve meticulous hemostasis
• Place a drain if necessary
• Close the wound in layers:
  • Close deep fascia with absorbable sutures
  • Close subcutaneous tissue with absorbable sutures
  • Close skin with non-absorbable sutures or staples

7. Specimen Handling

• Mark the specimen for orientation
• Send for pathological examination to:
  • Confirm diagnosis
  • Assess surgical margins
  • Rule out malignant transformation (which occurs in approximately 1% of cases) 5

Postoperative Management

1. Immediate Care:

   • Immobilize the arm in a sling for comfort
   • Monitor neurovascular status
   • Provide appropriate pain management

2. Follow-up Care:

   • Remove drain when output is minimal
   • Remove skin sutures/staples at 10-14 days
   • Begin passive range of motion exercises after wound healing
   • Progress to active range of motion and strengthening exercises

3. Surveillance:

   • For low-grade lesions: physical examination and imaging of the surgical site every 6-12 months for 2 years, then yearly as appropriate
   • Chest imaging as indicated to monitor for potential metastatic disease 1

Potential Complications and Management

1. Nerve Injury:

   • Particularly concerning for humeral osteochondromas near neurovascular structures 2
   • If nerve palsy occurs, early exploration and decompression may be necessary 4

2. Recurrence:

   • More common with incomplete resection, particularly if cartilage cap remains 6
   • Treat with repeat wide excision

3. Fracture:

   • Rare but possible, especially with large lesions
   • May require internal fixation if it occurs

4. Malignant Transformation:

   • Occurs in approximately 1% of solitary osteochondromas 5
   • Suspect if pain increases or tumor grows after skeletal maturity
   • Requires wide surgical excision if detected

Outcomes

With appropriate surgical technique, approximately 93% of preoperative symptoms resolve after excision of osteochondromas 4. The risk of recurrence is low with complete excision, and the functional outcome is typically excellent 3.