What are the surgical implications of a posterior approach in spinal surgery?

Surgical Implications of the Posterior Approach in Spinal Surgery

The posterior approach to the spine is universally applicable to all spinal segments but carries significantly higher morbidity due to extensive muscle dissection, resulting in increased postoperative pain, prolonged recovery, and elevated risks of wound infection and poor healing compared to anterior approaches. 1

Key Surgical Considerations

Indications and Applications

• The posterior approach is primarily indicated for decompression of epidural abscesses and can be used for any spinal segment. 1
• Posterior laminoforaminotomy is effective for treating cervical radiculopathy from soft lateral disc herniation or spondylotic foraminal narrowing, with good-to-excellent outcomes in 93-95.5% of patients. 1
• For lumbar stenosis without preexisting instability or deformity, in situ posterolateral fusion is NOT recommended as it provides no additional benefit over decompression alone. 1

Critical Technical Limitations

• Decompression of ventral epidural abscesses in the cervical or thoracic spine via posterior approach alone must be performed with extreme caution, as adequate access to anterior pathology is severely limited. 1
• Laminectomy rarely causes spinal destabilization unless substantial vertebral body destruction coexists. 1
• The American Association of Neurological Surgeons recommends subperiosteal dissection of paravertebral musculature to expose articular facets and pedicle screw entry points with high precision. 2

Major Morbidity Factors

Wound-Related Complications

• Posterior approaches require transgression of large muscle groups, leading to significantly longer recovery periods compared to anterior approaches. 1
• Dorsal incisions have substantially higher infection rates and poor wound healing, particularly in patients who remain recumbent postoperatively due to direct pressure on the wound and compromised wound care. 1
• Postoperative supine positioning significantly increases deep wound infection risk (P = 0.004), with Staphylococcus aureus being the most common pathogen; lateral decubitus positioning should be maintained postoperatively. 3

Pain and Recovery

• Posterior approaches are typically more painful than anterior approaches due to extensive muscle dissection. 1
• Muscle dissection and longer incision length contribute substantially to postoperative morbidity. 1

Comparative Outcomes: Posterior vs. Combined Approaches

Single Posterior vs. Anterior-Posterior Combined

• Single posterior approach demonstrates superior perioperative metrics including less intraoperative hemorrhage (P < 0.00001), shorter operative time (P < 0.00001), shorter hospital stay (P < 0.00001), and fewer complications (P < 0.00001) compared to combined anterior-posterior approaches. 4
• Clinical outcomes including pain scores, neurological improvement, and correction maintenance show no statistical difference between approaches. 4
• The complication rate is higher after anterior-posterior fusion compared to posterior approach alone for thoracolumbar fractures. 2

Instrumentation Considerations

Hardware Placement

• The American Society of Neurophysiological Monitoring recommends intraoperative electrophysiological monitoring (evoked and spontaneous EMG) during pedicle screw placement, with 100% sensitivity and 91-100% negative predictive value for detecting screw malposition. 2
• Titanium constructs are preferred as they are biologically inert with ultrastructurally smooth surfaces that minimize organism adherence. 1
• For lumbar stenosis without deformity or instability, pedicle screw instrumentation in conjunction with posterolateral fusion is NOT recommended. 1

Specific Clinical Scenarios

Cervical Radiculopathy

• Posterior laminoforaminotomy achieves good-to-excellent results in 93% of non-Worker's Compensation patients and 78% of Worker's Compensation patients (P < 0.01). 1
• Recurrent symptoms requiring reoperation occur in approximately 6.7% of patients. 1

Revision Surgery for Pseudarthrosis

• Posterior revision for anterior cervical pseudarthrosis achieves 100% fusion rate compared to 88% with anterior revision, with nonunion requiring reoperation occurring in 44% of anterior revisions versus only 2% of posterior revisions. 1

Common Pitfalls to Avoid

• Never attempt ventral decompression via posterior-only approach in cervical/thoracic spine without recognizing the severe access limitations. 1
• Avoid routine fusion in lumbar stenosis without documented instability, as it increases morbidity without improving outcomes. 1
• Maintain lateral decubitus positioning postoperatively rather than supine to reduce infection risk. 3
• Do not underestimate the prolonged recovery time and pain associated with extensive paraspinal muscle dissection. 1