Can lumbar and pelvic surgery impair coordinated trunk and hip muscle activation?

Lumbar and pelvic operations can affect the muscle systems that contribute to lumbopelvic control, particularly the multifidus. The overall proposed pathway—surgery causing impaired coordinated multifidus, abdominal, and gluteal activation that reduces dynamic stability—is biologically and biomechanically plausible, but not directly established as a complete causal sequence.

Postoperative functional evidence

• One month after minimally invasive lumbar fusion, paraspinal electromyographic activity remained reduced despite improvement in pain and function. During forward reaching, control shifted toward leg rather than trunk musculature, consistent with compensatory load sharing rather than restoration of normal trunk contribution.
• Corrective fusion cohorts showed increased gluteus maximus activity during bending. This may reflect compensation for surgically constrained lumbar motion and altered demands on the hip–pelvic system.
• Direct postoperative studies simultaneously measuring multifidus, abdominal, and gluteal activation—and linking their coordination to standardized dynamic-stability outcomes—are not available in the supplied evidence.

Mechanistic rationale

• Structural compromise of the multifidus is well supported after lumbar surgery. At the operative level, open fusion was associated with substantially greater multifidus cross-sectional-area loss than minimally invasive fusion (36.8% versus 12.2%).
• Postoperative MRI commonly shows multifidus atrophy and fatty infiltration. Early edema may reflect medial-branch dorsal-ramus injury; chronic denervation can lead to atrophy and fatty replacement.
• Because multifidus, abdominal muscles, and gluteals contribute to spinal–pelvic force closure, impaired multifidus capacity and compensatory lower-limb/gluteal recruitment provide a coherent mechanism for altered dynamic lumbopelvic control.

Bottom line

• The claim is plausible with moderate confidence: lumbar surgery can disrupt multifidus structure and recruitment and alter trunk–leg load sharing, with compensatory gluteal activation. Reduced dynamic lumbopelvic stability is a credible consequence, but a directly demonstrated, surgery-induced deficit in coordinated multifidus–abdominal–gluteal activation—especially after pelvic procedures—has not been shown.