Transabdominal muscle action potential lessons learned: when should decompression precede fusion? Illustrative cases

Area of Science:

• Neurosurgery
• Spinal Surgery

Background:

• Single-position prone lateral lumbar interbody fusion (pLLIF) allows for efficient surgical procedures without repositioning.
• Prone positioning offers flexibility in surgical sequencing and intraoperative decision-making.
• Advanced intraoperative neuromonitoring, such as transabdominal muscle action potential (TMAP) monitoring, provides critical real-time feedback on neurological status.

Purpose of the Study:

• To investigate the impact of surgical sequencing during pLLIF on neurological outcomes.
• To evaluate the utility of TMAP monitoring in guiding operative decisions related to surgical sequence.

Main Methods:

• A comparative case study of two patients with similar lumbar pathology undergoing pLLIF.
• Patients underwent pLLIF with proximal decompression in opposite operative sequences.
• Transabdominal muscle action potential (TMAP) monitoring was utilized to assess neurological responses to surgical sequencing.

Main Results:

• The patient who underwent interbody fusion before decompression experienced TMAP threshold elevations and postoperative motor deficit.
• The patient who underwent proximal decompression first showed TMAP signal stabilization and improvement, followed by uncomplicated interbody fusion.
• Surgical sequence significantly influenced neurological outcomes and TMAP signals in these cases.

Conclusions:

• Surgical sequencing in pLLIF can be clinically significant, particularly in patients with proximal canal stenosis.
• Event-based TMAP monitoring offers valuable real-time insights into sequence-dependent neural stress.
• Integrating TMAP monitoring with thoughtful surgical sequencing enhances intraoperative decision-making and patient neurological safety.