Is laminectomy necessary during multiple Smith-Peterson (or Ponte) spinal osteotomies?

Smith-Peterson/Ponte Spinal Osteotomies: Laminectomy Requirement

Laminectomy is an essential component of properly performed Smith-Peterson/Ponte spinal osteotomies, as the true Ponte osteotomy technique requires complete resection of the laminae to achieve adequate posterior shortening and optimal correction.

Understanding Smith-Peterson/Ponte Osteotomies

Smith-Peterson/Ponte osteotomies are posterior column procedures used to correct spinal deformities, particularly kyphosis. The technique involves:

• Complete resection of the posterior elements at the osteotomy level
• Removal of the spinous processes, ligamentum flavum, and facet joints
• Critically, removal of the laminae at the osteotomy sites

Technical Requirements

The true Ponte osteotomy, as described by its developer, requires:

1. Complete resection of the posterior elements including the laminae 1
2. Adequate bony resections to produce marked flexibility in extension, flexion, and rotation
3. Multiple levels of osteotomy to achieve desired correction

Evidence Supporting Laminectomy

The original description by Ponte himself emphasizes that "exact performance of the osteotomy with adequate bony resections, including the laminae, is an absolute condition to take full advantage of its properties" 1. This is considered the definitive technical description since it comes directly from the procedure's developer.

Clinical studies show that proper execution of Ponte osteotomies includes laminectomy:

• In a study of degenerative kyphosis, researchers measured "laminectomy time" as a standard component of the Ponte osteotomy procedure 2
• Research comparing Ponte osteotomies to 3-column osteotomies consistently includes laminectomy as part of the Ponte technique 3

Clinical Outcomes and Safety Considerations

When properly performed with laminectomy:

• Ponte osteotomies can achieve correction comparable to more invasive 3-column osteotomies (54.1% vs 54.4% correction) in appropriate cases 3
• The procedure has lower rates of neurological complications compared to vertebral column resection (VCR) procedures 3
• Modern techniques using ultrasonic bone knives for laminectomy during Ponte osteotomies have shown reduced blood loss and improved efficiency 2

Pitfalls and Misconceptions

A common error in clinical practice is performing incomplete resections and incorrectly labeling them as "Ponte osteotomies." As noted in the literature, "several publications use the term Ponte osteotomy loosely for by far incomplete resections and mixing it up with Smith-Petersen's osteotomy" 1.

Special Considerations

For patients with ankylosing spondylitis and severe kyphosis:

• Elective spinal osteotomy is generally not recommended due to high procedure-associated risks (4% perioperative mortality and 5% permanent neurologic sequelae) 4, 5
• Such procedures should only be considered in highly selected patients with major physical and psychological impairments due to loss of horizontal vision 4, 5
• When performed, these procedures should be done at specialized centers by surgeons with extensive experience 4

Conclusion

Based on the definitive technical description by the procedure's developer and supporting clinical evidence, laminectomy is an essential component of properly performed Smith-Peterson/Ponte spinal osteotomies. Incomplete resections that omit the laminae do not constitute true Ponte osteotomies and may result in suboptimal correction and outcomes.