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Updated: Sep 26, 2025
Full-Endoscopic Transforaminal Approach for Lumbar Discectomy
Published on: September 8, 2023
Magnetic Resonance Imaging Documentation of Approach Trauma With Lumbar Endoscopic Interlaminar, Translaminar,
Stefan Hellinger1, Albert E Telfeian2,3, Kai-Uwe Lewandrowski4,5,6
1Department of Orthopedic Surgery, Arabella Klinik, Munich, Germany.
Background:
Endoscopic spine surgery is associated with less approach trauma than conventional open translaminar surgery. However, objective evidence to corroborate this empiric observation is scarce. Preservation of the anatomic attachment and sensory function of multifidus muscles have been stipulated to be critical to maintaining the normal function of the lumbar spinal motion segment. The authors were interested in comparing the postoperative approach trauma between traditional open translaminar microsurgical and interlaminar endoscopic discectomy.
Methods:
The approach trauma to the paraspinal muscles due to interlaminar or open microsurgical discectomy was evaluated on T2-weighted axial magnetic resonance imaging (MRI) images of 39 consecutive patients who underwent lumbar disc surgery. Postoperative MRI images taken at 4 days and within 1 year after surgery were analyzed. Eleven patients underwent conventional open translaminar microdiscectomy surgery. Endoscopic discectomy was performed on 17 patients via the interlaminar and on another 11 patients via the transforaminal approach. The immediate surgical approach trauma was estimated as the defect zone by measuring the normalized relative cross-sectional area (rCSA) of muscle disruption in the surgical corridor 4 days postoperatively. The long-term effect of surgical approach trauma was assessed by measuring the area of the paraspinal muscles that had been replaced by fatty tissue 1 year postoperatively.
Results:
The rCSA data showed diminished approach trauma with a smaller surgical defect zone in the interlaminar endoscopy group (17.6%) was smaller than in the microsurgical group 4 days postoperatively (41.2%). At 1 year postoperatively, the mean fatty replacement of the paraspinal muscles was 23.6% after microsurgery and 2.1% after the interlaminar endoscopy. Muscle recovery was substantially reduced in the interlaminar endoscopic group, with the muscle zone reducing from 20.3% to 2.1% when analyzed 1 year postoperatively. In the microsurgery group, the muscle damage by atrophy increased from 41.2% to 62.9% at 1 year postoperatively (P < 0.001). Fatty replacement of the multifidus muscle was seen on the ipsilateral and contralateral approach side. There was a negligible change in the muscle zone with the transforaminal approach.
Conclusions:
Tissue trauma was significantly reduced with endoscopic surgery techniques compared with the traditional translaminar microdiscectomy approach. There was a minor postoperative tissue trauma and hardly any long-term replacement of the multifidus and paraspinal muscles by fatty tissue 1 year postoperatively with the endoscopic technique. The transforaminal approach has the least effect on the paraspinal muscles of the surgical motion segment. Further study is needed to investigate whether these findings translate into decreased postoperative instability or low back pain following endoscopic discectomy surgery.
Clinical Relevance:
MRI analysis of multifidus atrophy following various lumbar translaminar and transforaminal decompression techniques.
Insights
Endoscopic spine surgery causes less muscle trauma than open surgery. Interlaminar endoscopy significantly reduces paraspinal muscle damage and fatty replacement compared to microsurgery.
Area of Science:
- Spinal surgery techniques
- Minimally invasive procedures
- Musculoskeletal imaging
Background:
- Endoscopic spine surgery offers less approach trauma than open surgery.
- Preservation of multifidus muscles is crucial for lumbar spinal motion segment function.
- Objective evidence comparing surgical trauma between endoscopic and open techniques is limited.
Purpose of the Study:
- To compare postoperative approach trauma between traditional open translaminar microsurgical and interlaminar endoscopic discectomy.
- To evaluate the impact of different surgical approaches on paraspinal muscle integrity.
- To assess immediate and long-term effects on multifidus muscles.
Main Methods:
- Magnetic resonance imaging (MRI) analyzed approach trauma in 39 patients.
- T2-weighted axial MRI images assessed muscle disruption (defect zone) and fatty replacement.
- Compared open translaminar microdiscectomy (11 patients) with interlaminar (17) and transforaminal (11) endoscopic discectomy.
Main Results:
- Interlaminar endoscopy showed significantly less immediate muscle disruption (17.6% rCSA) than microsurgery (41.2%).
- One year post-surgery, microsurgery resulted in 23.6% fatty muscle replacement, versus 2.1% for interlaminar endoscopy.
- Transforaminal approach demonstrated negligible muscle zone changes.
Conclusions:
- Endoscopic techniques significantly reduce tissue trauma compared to traditional translaminar microdiscectomy.
- Endoscopic discectomy results in minimal postoperative tissue trauma and long-term muscle fatty replacement.
- The transforaminal approach has the least impact on paraspinal muscles; further research on clinical outcomes is warranted.
