The retrospective study was approved by our institutional review board (STUDY2021000113),&#160;and an informed consent waiver was granted because of the nature of the study. The procedure demonstrated in the video was performed on a human specimen that was obtained and utilized following the ethical guidelines and protocols established by our institution. The specimen was handled respectfully and in compliance with all relevant ethical standards.
1. Patient selection
<ol>
	<li>Select patients with degenerative lumbar disease and failed non-surgical treatment.</li>
	<li>Assess segment hypermobility or instability with flexion-extension X-ray images in addition to regular anteroposterior (AP) and lateral views (Figure 2). In cases of segment instability, perform an additional posterior fixation.</li>
	<li>Obtain a computed tomography (CT) and magnetic resonance (MR)-scan of the lumbar spine.</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66878/66878fig02.jpg" /> 
Figure 2: Pre-operative and follow-up X-ray images in A.P and lateral view. (A-B) Multilevel degenerative lumbar spine disease with collapsed disc space L3/4 as well as L4/5 and neuroforaminal stenosis. No signs of instability or hyperflexible were observed. (C-D) One-year post-operative follow up. Correct position of PEEK cages in L3/4 and L4/5 disc space without subsidence. Both disc and neuroforaminal height are restored. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66878/66878fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
2. Positioning
<ol>
	<li>Position the patient, under general anesthesia, in a right-sided decubitus position with partially flexed hips and knees on a radiolucent operating table. Pad bony prominences to avoid soft tissue damage due to pressure.</li>
	<li>Secure the patient with surgical tape and belts/pads to prevent movement and ensure safety.</li>
	<li>Flex the operating table to generate more space if needed.</li>
</ol>
3. Preoperative phase
<ol>
	<li>Confirm the desired surgical level with AP/lateral fluoroscopy images.</li>
	<li>Use skin markers to visualize the disc space and vertebral bodies of the desired level on the skin surface (Figure 3).</li>
	<li>Place electrodes for electromyography (EMG) on reference muscles for nerves that could be at risk during surgery17.</li>
</ol>
4. Approach
<ol>
	<li>After disinfecting the skin and covering the area with the surgical drape, according to institutional standards, make a 3-5 cm long skin incision using a sterile scalpel over the disc space in a single-level surgery.</li>
	<li>Use electrocautery to dissect the fascia abdominalis.</li>
	<li>Open the fascia and use clamps/retractors to bluntly split the three layers of the obliques until the retroperitoneal space is reached.</li>
	<li>Identify the psoas and split it in the longitudinal direction (for example, using retractors).</li>
</ol>
5. Neuromonitoring
<ol>
	<li>Look out for any changes in somatosensory evoked potentials (SSEP), motor evoked potentials (MEP), and spontaneous electromyography (EMG) during approach and when dissecting the psoas17.</li>
	<li>Using a handheld EMG probe, identify the exiting nerve root at the desired level.</li>
</ol>
6. Retractors
<ol>
	<li>After fluoroscopically confirming the desired level, place a self-retaining retractor system (Figure 4).</li>
</ol>
7. Preparation of intradiscal space
<ol>
	<li>Use a scalpel to perform an annulotomy and resect all discal material using a rongeur. 
	NOTE: In severe degeneration, the disc space may be obscured by osteophytes. These may need resection before evacuation of the discal space.</li>
	<li>Place a spreader to open the collapsed intervertebral space. 
	NOTE: In cases of severe degeneration, only partial restoration of the intervertebral space may be possible.</li>
	<li>Carefully remove disc material and cartilage from both endplates using Curettes or Cobb elevators (Figure 4).</li>
</ol>
8. Placement of trail cage
<ol>
	<li>Use different trial components to restore normal disc height and to relieve any pressure on nerve roots. 
	NOTE: The trial position is verified using fluoroscopy from both the AP and lateral views. The endplates should be symmetrically elevated (Figure 4).</li>
</ol>
9. Cage implantation
<ol>
	<li>After identifying the correct size, implant the cage under fluoroscopic guidance (Figure 5).</li>
	<li>Obtain final fluoroscopic images in A.P. and lateral view.</li>
</ol>
10. Closure
<ol>
	<li>Use irrigation and perform a final hemostasis check.</li>
	<li>Carefully remove all retractors and spreaders.</li>
	<li>Close the wound in a multilayered fashion.</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/66878/66878fig03.jpg" /> 
Figure 3: Identification of disc level. (A-B): Marking the desired level in anteroposterior (AP) and lateral view. (C) Identification of the desired level in the lateral view fluoroscopy. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66878/66878fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/66878/66878fig04.jpg" /> 
Figure 4: Interoperative view during LLIF. (A) Position of Retractors on AP view. (B) Intraoperative verification of the correct level using fluoroscopy lateral view with retractors in place. (C) View on disc-level through Retractors. The disc was removed, with some cartilage left. (D) Intraoperative fluoroscopy AP view, with a trial cage in place. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66878/66878fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/66878/66878fig05.jpg" /> 
Figure 5: Intraoperative view with implanted cage. (A) Intraoperative view through retractors.&#160;Visualization of the implanted cage. (B-C) Fluoroscopy with the cage in place. Correct positioning of the cage with restoration of disc height. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66878/66878fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
11. In-hospital postoperative phase
<ol>
	<li>Encourage patients to mobilize without a brace within hours by providing adequate pain medication or other pain management techniques.</li>
	<li>Provide the patient with a clear diet until the patient has passed flatus, then advance to a regular diet.</li>
	<li>Perform a recommended inspection and manual palpation of the flanks and a formal dressing check before discharge.</li>
</ol>
12. Outpatient postoperative phase
<ol>
	<li>After two weeks, perform a formal wound check.</li>
	<li>Advise the patients not to perform bending/lifting/twisting movements greater than 15 lbs.</li>
</ol>
13. Follow up
<ol>
	<li>At six weeks obtain postoperative X-rays and initiate 6 weeks of formalized physical therapy and education in trunk mechanics (Figure 2).</li>
	<li>At 3 months perform a formal evaluation. If concern for pseudoarthrosis arise obtain a CT with MPR (multiplanar reformatting) or MIP (maximum intensity projection) post-processing tools to assess for continuity of the fusion.</li>
	<li>At six months, perform a neurological evaluation and obtain standard radiographs.</li>
	<li>Release patient from care after a last clinical and radiological follow-up one-year post-surgery.</li>
</ol>

<ol>
	<li>Luoma, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Low+back+pain+in+relation+to+lumbar+disc+degeneration.">Low back pain in relation to lumbar disc degeneration.</a> Spine. 25 (4), 487-492 (2000).</li><li>Rabau, O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+lumbar+interbody+fusion+(LLIF):+An+update.">Lateral lumbar interbody fusion (LLIF): An update.</a> Global Spine J. 10 (2_suppl), 17S-21S (2020).</li><li>Pimenta, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Less-invasive+lateral+lumbar+interbody+fusion+(XLIF)+surgical+technique:+video+lecture.">Less-invasive lateral lumbar interbody fusion (XLIF) surgical technique: video lecture.</a> Eur Spine J. 24 Suppl 3 (S3), 441-442 (2015).</li><li>Pimenta, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+endoscopic+transpsoas+retroperitoneal+approach+for+lumbar+spine+surgery.">Lateral endoscopic transpsoas retroperitoneal approach for lumbar spine surgery.</a> Presented at VIII Brazilian Spine Society Meeting. , (2001).</li><li>Ozgur, B. 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T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-position+prone+lateral+interbody+fusion+improves+segmental+lordosis+in+lumbar+spondylolisthesis.">Single-position prone lateral interbody fusion improves segmental lordosis in lumbar spondylolisthesis.</a> World Neurosurg. 151, e786-e792 (2021).</li><li>. XLIF Nuvasive Available from: <a target="_blank" href="https://www.nuvasive.com/procedures/spine/xlif20/">https://www.nuvasive.com/procedures/spine/xlif20/</a> (2025)</li><li>. DLIF Metronic Available from: <a target="_blank" href="https://thespinemarketgroup.com/wp-content/uploads/2020/07/Direct-Lateral-Surgical-Technique-Medtronic.pdf">https://thespinemarketgroup.com/wp-content/uploads/2020/07/Direct-Lateral-Surgical-Technique-Medtronic.pdf</a> (2025)</li><li>. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+decision-making+pathway+for+utilizing+standalone+lateral+lumbar+interbody+fusion.">Development of a decision-making pathway for utilizing standalone lateral lumbar interbody fusion.</a> Eur Spine J. 31 (7), 1611-1620 (2022).</li><li>Camino-Willhuber, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumbar+lateral+interbody+fusion:+step-by-step+surgical+technique+and+clinical+experience.">Lumbar lateral interbody fusion: step-by-step surgical technique and clinical experience.</a> J Spine Surg. 9 (3), 294-305 (2023).</li><li>Kwon, B., Kim, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+lumbar+interbody+fusion.">Lateral lumbar interbody fusion.</a> J Am Acad of Orthop Surg. 24 (2), 96-105 (2016).</li><li>Lall, R. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraoperative+neurophysiological+monitoring+in+spine+surgery:+indications,+efficacy,+and+role+of+the+preoperative+checklist.">Intraoperative neurophysiological monitoring in spine surgery: indications, efficacy, and role of the preoperative checklist.</a> Neurosurg Focus. 33 (5), E10 (2012).</li><li>Taba, H. A., Williams, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+lumbar+interbody+fusion.">Lateral lumbar interbody fusion.</a> Neurosurg Clin of N Am. 31 (1), 33-42 (2020).</li><li>Rodgers, W. B., Gerber, E. J., Patterson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intraoperative+and+early+postoperative+complications+in+extreme+lateral+interbody+fusion.">Intraoperative and early postoperative complications in extreme lateral interbody fusion.</a> Spine. 36 (1), 26-32 (2011).</li><li>Moro, T., Kikuchi, S., Konno, S., Yaginuma, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+anatomic+study+of+the+lumbar+plexus+with+respect+to+retroperitoneal+endoscopic+surgery.">An anatomic study of the lumbar plexus with respect to retroperitoneal endoscopic surgery.</a> Spine. 28 (5), 423-427 (2003).</li><li>Ng, J. P. H., Kaliya-Perumal, A. K., Tandon, A. A., Oh, J. Y. 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G., Yu, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumbar+plexus+safe+working+zones+with+lateral+lumbar+interbody+fusion:+a+systematic+review+and+meta-analysis.">Lumbar plexus safe working zones with lateral lumbar interbody fusion: a systematic review and meta-analysis.</a> Eur Spine J. 31 (10), 2527-2535 (2022).</li><li>Godolias, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumbosacral+plexus+3D+printing+with+dissection+validation+-+a+baseline+study+with+regards+to+lateral+spine+surgery.">Lumbosacral plexus 3D printing with dissection validation - a baseline study with regards to lateral spine surgery.</a> Interdiscip Neurosurg. 31, 101666 (2023).</li><li>Agarwal, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lateral+lumbar+interbody+fusion+in+the+elderly:+a+10-year+experience.">Lateral lumbar interbody fusion in the elderly: a 10-year experience.</a> J Neurosurg Spine. 29 (5), 525-529 (2018).</li><li>Chen, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cage+subsidence+and+fusion+rate+in+extreme+lateral+interbody+fusion+with+and+without+fixation.">Cage subsidence and fusion rate in extreme lateral interbody fusion with and without fixation.</a> World Neurosurg. 122, 969-977 (2019).</li><li>Wang, Y., Beydoun, M. 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Trends, patterns, disparities, and future projections for the obesity epidemic.</a> Int J Epidemiol. 49 (3), 810-823 (2020).</li><li>Barrie, U., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+obesity+on+complications+and+surgical+outcomes+after+adult+degenerative+scoliosis+spine+surgery.">Impact of obesity on complications and surgical outcomes after adult degenerative scoliosis spine surgery.</a> Clin Neurol Neurosurg. 226, 107619 (2023).</li><li>Shasby, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erratum.+Does+minimally+invasive+spine+surgery+improve+outcomes+in+the+obese+population?+A+retrospective+review+of+1442+degenerative+lumbar+spine+surgeries.">Erratum. Does minimally invasive spine surgery improve outcomes in the obese population? 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Conflict of interest Jens Chapman MD receives consulting fees from Globus Medical Inc. Rod Oskouian MD receives royalties from Stryker and consulting fees from Seaspine, Globus Medical Inc., Stryker, DePuy Synthes, Medtronic and ATEC. All other authors have no relevant financial or non-financial interests to disclose.

Lateral Lumbar Interbody Fusion (LLIF) has become a popular minimally invasive technique for achieving arthrodesis. Since its introduction, indications have expanded for the treatment of various lumbar conditions such as degenerative diseases, deformity, and lumbar spinal pathologies. It allows implantation of larger interbody cages than TLIF or PLIF across the apophysis leading to effective correction of coronal deformities and indirect decompression of the neuroforamina by restoring disc height18,19.
When planning a stand-alone trans-psoas lateral interbody fusion procedure a careful patient selection is helpful for good results, especially in light of the risk of undue subsidence vertebral fracture and non-unions. Overall, this procedure has been shown to be an effective and safe procedure12.
Preoperative MR-images can be used to assess surgical disruption of the psoas major, abdominal vessels, and lumbar plexus. Assessment of the psoas muscle is needed to assess if a trans-psoas or pre-psoas lateral approach is favorable. Moro et al. introduced a definition of anatomical zones with respect to the disc space to assess safe zones20. This classification was later modified, providing more specific subtypes, to aid in the feasibility and safety of between approaches21. In cases of obstruction by vascular structures or a high-rising-psoas, a pre-psoas approach is not recommended21. Anatomical and MR studies concluded that a secure trans-psoas pathway does not exist without potentially damaging the plexus22,23. Utilizing innovative 3D reconstructions of MR-scan and 3D prints of the lumbar plexus may help to identify structures at risk at the desired disc-level. A study conducted at our facility showed the feasibility of this project, impressively marking each individual nerve branch24. Recall that with patient positioning the lumbar plexus can be significantly displaced ventrally, leading to false information provided by pre-operative supine position imaging23.
When performing this procedure, there are various pitfalls to consider. Among other things, reposition the patient rather than tilting the table extremely to achieve an orthogonal position. This allows for a more secure position and less intra-operative movement. During the access, perform a blunt dissection of the abdominal muscles rather than using electrocautery excessively. Additionally, changes in neuromonitoring may occur due to traversing nerve root. If there is a loss of signal from SSEP or EMG continue to retract dorsally. Nerve damage on the contralateral side can be avoided by careful resection of the disc space, especially on the contralateral side. Remember that oversized implants may lead to cage subsidence and endplate fractures
There is a risk of pseudarthrosis and cage subsidence, with osteoporosis as a major risk factor13,25. High-grade endplate sclerosis, such as Modic II, has been reported a predisposing factor towards successful fusion14. In a recent systematic review, pre-psoas procedures were reported to not have significant differences in subsidence or pseudarthrosis. In our own study, we observed similar results. Notably, compared to ALIF a slightly lower rate of this complication was found12,13. A combination of LLIF, regardless of the approach used, with internal fixation may be beneficial in selected cases, with a higher biomechanical stability and improvement of the lumbar lordotic angle reported. However, there was no difference in the rate of cage subsidence compared to a stand-alone trans-psoas lateral interbody fusion26.
Over the last decades the incidence of obesity has increased significantly27. Thus, the proportion of patients requiring Spine surgery has increased as well. In spine surgery obese patients showed an increase in operation time, estimated blood lost, length of hospital stay, and higher rate of complications, thus putting a significant additional burden on healthcare economics28. Carroll et al. investigated the outcome of obese patients in minimally invasive posterior spine surgery (MIS). Obese patients still benefited from MIS by reducing estimated blood loss, operation time, and surgical infection when compared to traditional open techniques. Interestingly, compared to a non-obese population who received MIS, they still had poorer outcomes. It showed longer operation time with greater estimated blood loss. Additionally, the need for revision surgery and readmission rates were significantly higher. This study also raises the issue that specialized surgical instruments may be needed if the patient size exceeds retractor length29. Although the effects of LLIF have not been studied in this population, similar results may be applicable.
The most predominant complication of trans-psoas/pre-psoas procedures is approach related. Walker et al. showed in their systematic review that the most common complications were transient sensory symptoms at 21.7%. A transient hip-flexor motor weakness was found at 19.7%. Persistent neurological symptoms were found in 2.8% of all cases13. In our study, temporary hip flexor weakness was observed in 8% 12. The pre-psoas group showed significantly fewer rates of transient neurological deficits (sensory 8.7%; motor 5.7%), and permanent damage is rare. This is likely due to the lack of psoas disruptions during the pre-psoas approach. Thus, the risk of damage from manipulating the intramuscular lumbar plexus is reduced. However, increased risks of major vascular, ureteral, bowel injury and sympathetic plexus damage are reported13. Overall, vascular and visceral complications such as bowel or urological injuries are rare at around 1%13,30. Vascular injuries were due to patient positioning. The vena cava and iliac veins were found to be at most risk using a right-sided approach31. Wound infections were relatively low, ranging around 1.3% to 3.1% in our study and the systematic review12,13. These rates are comparable to different spinal procedures.
Many studies have shown that a stand-alone lateral interbody fusion is a relatively safe procedure for the treatment of certain types of degenerative lumbar spine disease, foraminal stenosis, and some adult spine deformities. Optimized patient selection and knowledge of structures at risk are vital for a successful procedure and good patient outcome. The use of innovative 3D images or 3D prints obtained from pre-operative scans may be beneficial in identifying structures at risk. Compared to other techniques, the trans-psoas approach allows for the implantation of larger interbody cages and the effective correction of deformities. The most dominant complications are transient neurological defects and wound infections. The pre-psoas approach utilizing neuromonitoring offers reduced muscle disruption and potentially a faster recovery compared to other spine fusion techniques. However, the procedure is recommended to be performed by a skilled surgical team well-versed in neuromonitoring and lateral access spine surgery techniques.

Lower back pain, an important symptom of degenerative lumbar disease (DLD), is common in patients over 65 years1. Other symptoms of DLD include radiculopathy and claudication. When non-surgical treatment fails, surgical decompression or, if indicated, interbody fusion of the spine may be a viable treatment option2. Several techniques and approaches have been developed to achieve interbody fusion or decompression of the segment. Traditional approaches include posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF). Approaches to the lumbar spine are illustrated in Figure 1.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66878/66878fig01.jpg" /> 
Figure 1: Different approaches to the lumbar spine for interbody fusion12. Overview of the different approaches used for lumbar interbody fusion. LLIF is a trans-psoas approach, and OLIF is a pre-psoas approach. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66878/66878fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
Over the last decades, minimally invasive techniques for interbody fusion of the lumbar spine have been developed to reduce tissue damage and complications, allowing for quicker patient recovery, reducing complications, and surpassing the technical limitations of traditional approaches to the spine. In 2001, Pimenta et al. introduced a minimally invasive retroperitoneal approach to the lumbar spine by splitting the psoas, providing direct disc exposure by expanding the retroperitoneal space. This has been introduced as the lateral trans-psoas approach3,4. This technique was modified with the use of special retractors and popularized by Ozgur et al.5. In recent years, extreme lateral interbody fusion in a prone patient position has been developed. This technique offers efficiency with combined posterior procedures and improved lumbar lordosis6,7.
Lateral interbody fusion (LLIF) can be achieved utilizing various approaches. These include trans-psoas approaches (extreme lateral interbody fusion (XLIF8), direct lateral interbody fusion (DLIF9) using different instruments), and a pre-psoas approach (oblique lateral interbody fusion (OLIF10). The approach used for the procedure depends on the patient and the surgeon&#39;s training, among others. Anatomical studies showed notable benefits for trans-psoas approaches (minimal blood loss, preservation of the posterior musculature and ligamentous chain, the ability to perform an extensive discectomy, and placement of a large intervertebral graft) but also disadvantages (post-operative nerve palsies, visceral abdominal injuries)11. Reported major but rare complications include intestinal perforation, common iliac vein injury, cage subsidence, vertebral body fractures around the interbody device, retroperitoneal hematoma, and pneumoretroperitoneum with an associated pneumoscrotum12. Overall, pre-psoas approaches are associated with a slightly lower complication rate and fewer postoperative neurological deficits13. To allow optimal outcome, the indication for a lateral interbody fusion needs to be done carefully. We advise obtaining a computed tomography (CT) and magnetic resonance (MR)-scan of the lumbar spine. To assess the segment hypermobility or instability, obtain flexion-extension X-ray images besides regular anteroposterior (AP) and lateral. Common indications are patients with segmental instability and concurrent radiculopathy who have failed non-surgical treatment. In the case of segmental instability or deformity surgery, additional internal fixation may be necessary. LLIF may be limited in the lower lumbar spine, depending on the height of the iliac crest. Supplemental posterior fixation may add valuable construct stiffness and deformity reduction for patients with high-grade instability, deformity, or questionable bone stability. Contraindications for this procedure are typically malignancy, high-grade deformities, or bifurcation abnormalities. A history of retroperitoneal infection or disease and previous retroperitoneal surgery or injury are important considerations. Risk factors for poor outcomes include osteoporosis, smoking, long-term steroid use, severe deformities, and segment hypermobility due to facet effusion or previous laminectomy14,15,16. Also, patients with very low body mass index and anterior psoas location are potentially adverse patients for increased complexity of access. In revision surgery, a pre-psoas approach may be favorable to avoid scar tissue.
The aim of this article is to provide step-by-step guidance to surgeons on a stand-alone lateral trans-psoas interbody fusion, including pitfalls and complication rates after 10 years of single-center experience.

<table><tbody><tr><td>100mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244100</td><td></td></tr><tr><td>100mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243100</td><td></td></tr><tr><td>100mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241100</td><td></td></tr><tr><td>100mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242100</td><td></td></tr><tr><td>110mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244110</td><td></td></tr><tr><td>110mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243110</td><td></td></tr><tr><td>110mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241110</td><td></td></tr><tr><td>110mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242110</td><td></td></tr><tr><td>120mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244120</td><td></td></tr><tr><td>120mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243120</td><td></td></tr><tr><td>120mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241120</td><td></td></tr><tr><td>120mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242120</td><td></td></tr><tr><td>130mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244130</td><td></td></tr><tr><td>130mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243130</td><td></td></tr><tr><td>130mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241130</td><td></td></tr><tr><td>130mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242130</td><td></td></tr><tr><td>140mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244140</td><td></td></tr><tr><td>140mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243140</td><td></td></tr><tr><td>140mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241140</td><td></td></tr><tr><td>140mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242140</td><td></td></tr><tr><td>150mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244150</td><td></td></tr><tr><td>150mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243150</td><td></td></tr><tr><td>150mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241150</td><td></td></tr><tr><td>150mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242150</td><td></td></tr><tr><td>160mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244160</td><td></td></tr><tr><td>160mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243160</td><td></td></tr><tr><td>160mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241160</td><td></td></tr><tr><td>160mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242160</td><td></td></tr><tr><td>50mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244050</td><td></td></tr><tr><td>50mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241050</td><td></td></tr><tr><td>50mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242050</td><td></td></tr><tr><td>60mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244060</td><td></td></tr><tr><td>60mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241060</td><td></td></tr><tr><td>60mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242060</td><td></td></tr><tr><td>70mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244070</td><td></td></tr><tr><td>70mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241070</td><td></td></tr><tr><td>70mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242070</td><td></td></tr><tr><td>80mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244080</td><td></td></tr><tr><td>80mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241080</td><td></td></tr><tr><td>80mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242080</td><td></td></tr><tr><td>90mm Aluminum Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3244090</td><td></td></tr><tr><td>90mm Electrode Center Blade&amp;nbsp;</td><td>Nuvasive</td><td>3243090</td><td></td></tr><tr><td>90mm Left Blade&amp;nbsp;</td><td>Nuvasive</td><td>3241090</td><td></td></tr><tr><td>90mm Right Blade&amp;nbsp;</td><td>Nuvasive</td><td>3242090</td><td></td></tr><tr><td>ALGI Penfield, Long Push&amp;nbsp;</td><td>Nuvasive</td><td>3300118</td><td></td></tr><tr><td>Anterior Crossbar&amp;nbsp;</td><td>Nuvasive</td><td>3240003</td><td></td></tr><tr><td>Bayonetted Shim Inserter&amp;nbsp;</td><td>Nuvasive</td><td>3200215</td><td></td></tr><tr><td>Blade Rotation Driver&amp;nbsp;</td><td>Nuvasive</td><td>3240005</td><td></td></tr><tr><td>Dilator - 12mm&amp;nbsp;</td><td>Nuvasive</td><td>1010968</td><td></td></tr><tr><td>Dilator - 6mm&amp;nbsp;</td><td>Nuvasive</td><td>1010966</td><td></td></tr><tr><td>Dilator - 9mm&amp;nbsp;</td><td>Nuvasive</td><td>1010967</td><td></td></tr><tr><td>Fixation Shim Screw Driver&amp;nbsp;</td><td>Nuvasive</td><td>3200052</td><td></td></tr><tr><td>Fluoro Modulator&amp;nbsp;</td><td>Nuvasive</td><td>3220131</td><td></td></tr><tr><td>Hex Driver (3/32&amp;rdquo;)&amp;nbsp;</td><td>Nuvasive</td><td>1011691</td><td></td></tr><tr><td>Hex Key (3/32&amp;rdquo;)&amp;nbsp;</td><td>Nuvasive</td><td>1011748</td><td></td></tr><tr><td>Initial Dilator Holder&amp;nbsp;</td><td>Nuvasive</td><td>3230140</td><td></td></tr><tr><td>K-wire (13.5&amp;rdquo;)&amp;nbsp;</td><td>Nuvasive</td><td>3230101</td><td></td></tr><tr><td>Light Cable Adapter, Storz&amp;nbsp;</td><td>Nuvasive</td><td>1011811</td><td></td></tr><tr><td>Lock Shim Inserter/Repositioning Tool&amp;nbsp;</td><td>Nuvasive</td><td>3240001</td><td></td></tr><tr><td>Lock Shim Inserter/Repositioning Tool,</td><td>Nuvasive</td><td></td><td></td></tr><tr><td>Low-Profile Shim</td><td>Nuvasive</td><td>3240002</td><td></td></tr><tr><td>MaXcess 4 4th Blade Attachment&amp;nbsp;</td><td>Nuvasive</td><td>3240004</td><td></td></tr><tr><td>Maxcess 4 Access System</td><td>Nuvasive</td><td></td><td>Tray with XLIF Dilator and Retractors in different seizes</td></tr><tr><td>MaXcess 4 Articulating Arm&amp;nbsp;</td><td>Nuvasive</td><td>3240121</td><td></td></tr><tr><td>MaXcess 4 Blade, 180mm Electrode Ctr&amp;nbsp;</td><td>Nuvasive</td><td>3243180</td><td></td></tr><tr><td>Needle Electrodes&amp;nbsp;</td><td>Nuvasive</td><td>8050029</td><td>NVM5 System</td></tr><tr><td>Surface Electrodes&amp;nbsp;</td><td>Nuvasive</td><td>8020029</td><td>NVM5 System</td></tr><tr><td>Targeting Instrument&amp;nbsp;</td><td>Nuvasive</td><td>3240000</td><td></td></tr><tr><td>XL (18mm wide)</td><td>Nuvasive</td><td>1000-00-0716</td><td>Implant&amp;nbsp;</td></tr><tr><td>XL-F (18mm wide)&amp;nbsp;</td><td>Nuvasive</td><td>1000-00-0719</td><td>Implant&amp;nbsp;</td></tr><tr><td>XL-F Wide (22mm wide)</td><td>Nuvasive</td><td>1000-00-0720</td><td>Implant&amp;nbsp;</td></tr><tr><td>XLIF Annulus Cutter, 4x14mm&amp;nbsp;</td><td>Nuvasive</td><td>6942414</td><td></td></tr><tr><td>XLIF Annulus Cutter, 4x16mm&amp;nbsp;</td><td>Nuvasive</td><td>6942416</td><td></td></tr><tr><td>XLIF Cobb, 12mm Straight&amp;nbsp;</td><td>Nuvasive</td><td>6940012</td><td></td></tr><tr><td>XLIF Cobb, 18mm Down&amp;nbsp;</td><td>Nuvasive</td><td>6940118</td><td></td></tr><tr><td>XLIF Cobb, 18mm Straight&amp;nbsp;</td><td>Nuvasive</td><td>6940018</td><td></td></tr><tr><td>XLIF Cobb, 22mm Straight&amp;nbsp;</td><td>Nuvasive</td><td>6940022</td><td></td></tr><tr><td>XLIF Cobb, Serrated&amp;nbsp;</td><td>Nuvasive</td><td>6940001</td><td></td></tr><tr><td>XLIF Cutter, 8mm Disc&amp;nbsp;</td><td>Nuvasive</td><td>6940151</td><td></td></tr><tr><td>XLIF Forceps, Bipolar Str Extra Long&amp;nbsp;</td><td>Nuvasive</td><td>3200322</td><td></td></tr><tr><td>XLIF Handle, Slide&amp;nbsp;</td><td>Nuvasive</td><td>6940004</td><td></td></tr><tr><td>XLIF Inserter, Angled XL&amp;nbsp;</td><td>Nuvasive</td><td>D6904485</td><td></td></tr><tr><td>XLIF Kerrison, 2mm&amp;nbsp;</td><td>Nuvasive</td><td>6940132</td><td></td></tr><tr><td>XLIF Kerrison, 5mm&amp;nbsp;</td><td>Nuvasive</td><td>6940135</td><td></td></tr><tr><td>XLIF Nerve Retractor, Extra Long&amp;nbsp;</td><td>Nuvasive</td><td>3300319</td><td></td></tr><tr><td>XLIF Paddle Sizer, 4x16mm&amp;nbsp;</td><td>Nuvasive</td><td>6940416</td><td></td></tr><tr><td>XLIF Paddle Sizer, 6x18mm&amp;nbsp;</td><td>Nuvasive</td><td>6940618</td><td></td></tr><tr><td>XLIF Paddle Sizer, 6x22mm&amp;nbsp;</td><td>Nuvasive</td><td>6940622</td><td></td></tr><tr><td>XLIF Penfield, Pull Extra Long&amp;nbsp;</td><td>Nuvasive</td><td>3300318</td><td></td></tr><tr><td>XLIF Pituitary, Large&amp;nbsp;</td><td>Nuvasive</td><td>6940431</td><td></td></tr><tr><td>XLIF Pituitary, Medium&amp;nbsp;</td><td>Nuvasive</td><td>6940430</td><td></td></tr><tr><td>XLIF Pituitary, Small&amp;nbsp;</td><td>Nuvasive</td><td>6940429</td><td></td></tr><tr><td>XLIF Rasp&amp;nbsp;</td><td>Nuvasive</td><td>6940340</td><td></td></tr><tr><td>XLIF Scraper, Endplate&amp;nbsp;</td><td>Nuvasive</td><td>6940020</td><td></td></tr><tr><td>XLIF Slide, Bayonetted&amp;nbsp;</td><td>Nuvasive</td><td>6940063</td><td></td></tr><tr><td>XLIF Slide, XW Bayonetted&amp;nbsp;</td><td>Nuvasive</td><td>6940064</td><td></td></tr><tr><td>XLIF Suction, 12FR Extra Long&amp;nbsp;</td><td>Nuvasive</td><td>3300320</td><td></td></tr><tr><td>XLIF Suction, 15FR Extra Long&amp;nbsp;</td><td>Nuvasive</td><td>3300321</td><td></td></tr><tr><td>XL-W (22mm wide)</td><td>Nuvasive</td><td>1000-00-0717</td><td>Implant&amp;nbsp;</td></tr><tr><td>XL-XW (26mm wide)&amp;nbsp;</td><td>Nuvasive</td><td>1000-00-0718</td><td>Implant&amp;nbsp;</td></tr></tbody></table>

surgical approach and complications of stand-alone lateral trans-psoas interbody fusion

Interbody fusion of the lumbar spine is a standard procedure for symptomatic degenerative lumbar spine disease if conservative treatment fails. Surgical decompression and fusion of the segment can be achieved using several different techniques. Over the last decades, minimally invasive techniques, such as lateral interbody fusion (LLIF), have been developed to reduce tissue damage and complications and allow quicker patient recovery. With growing popularity, indications for LLIF have expanded to treat spinal deformities and foraminal/central stenosis. Mechanically, it allows for an unsurpassed fixation through the left-to-right apophyseal ring placement of the cage. LLIF utilizes a minimally disruptive retroperitoneal corridor and includes both trans-psoas and pre-psoas approaches. For the pre-psoas approach, the risk of damage from manipulation of the intramuscular lumbar plexus is reduced compared to a trans-psoas approach. However, increased risks of major vascular, ureteral, bowel injury and sympathetic plexus damage are reported.
This article aims to provide a detailed and comprehensive guide on stand-alone lateral trans-psoas interbody fusion, including its indications, surgical procedure, potential complications, and outcomes based on a decade of experience from a single center.

In our recent study, we investigated the complication rates following a stand-alone lateral interbody fusion12. We retrospectively investigated 158 patients (145 trans-psoas, 13 pre-psoas) who received an LLIF between 2016 and 2020, with a mean follow-up of 14 months (Table 1).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Patient characteristics&#160;</td>
			<td>All (n=158)</td>
			<td>Trans-psoas (n=145)</td>
			<td>Pre-proas (n=13)</td>
		</tr>
		<tr>
			<td>Age (years)</td>
			<td>65 &#177; 10&#160;</td>
			<td>65 &#177; 10&#160;</td>
			<td>65 &#177; 11</td>
		</tr>
		<tr>
			<td>Male (n)</td>
			<td>70 (44%)</td>
			<td>62 (43%)</td>
			<td>8 (62%)</td>
		</tr>
		<tr>
			<td>Isolated stenosis (%)</td>
			<td>94 (60%)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stenosis in Adult deformity&#160;</td>
			<td>37 (23%)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adult deformity&#160;</td>
			<td>27 (18%)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical time (min.)</td>
			<td>266 (&#177; 113)</td>
			<td>269 (&#177; 116)</td>
			<td>233 (&#177; 78)</td>
		</tr>
		<tr>
			<td>Blood loss (mL)</td>
			<td>120 (&#177; 187)</td>
			<td>121 (&#177; 195)</td>
			<td>109 (&#177; 58)</td>
		</tr>
		<tr>
			<td>Fused levels&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1</td>
			<td>127 (81%)</td>
			<td>117 (81%)</td>
			<td>10 (77%)</td>
		</tr>
		<tr>
			<td>2</td>
			<td>29 (19%)</td>
			<td>26 (18%)</td>
			<td>3 (23%)</td>
		</tr>
		<tr>
			<td>3</td>
			<td>2 (1%)</td>
			<td>2 (1%)</td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 1: Patient demographics
All procedures were performed by two senior spine surgeons. The combined expertise of both surgeons surpassed a decade of specialization in lateral spine surgery. Patients with a history of previous spinal operations were not included in the study. The primary pathologies were stenosis due to adult spinal deformity (60%) and isolated stenosis (23%). The average blood loss was 121 mL (&#177; 195 mL). Most patients received a single-level fusion in both study cohorts (81% trans-psoas; 77% pre-psoas). However, only patients in the trans-psoas group received a 3-level fusion (1%). An example of multilevel fusion is illustrated in Figure 2.
Overall, we observed a complication rate of 19.6%. The most prevalent complication observed was a temporary weakness of the hip flexor (8%) on the same side as the surgical procedure. This weakness, however, was completely resolved in all patients by their final clinical follow-up. Notably, four patients (2.5%) experienced significant bleeding exceeding 500 mL. A single patient (0.6%) endured permanent damage to the femoral nerve, resulting in considerable muscle atrophy during the follow-up period. In this case, electromyography alerts were triggered multiple times during intraoperative neuromonitoring. In accordance with a standardized institutional protocol, the retractor was temporarily closed until the neuromonitoring normalized, for a minimum of 5 minutes, before being reopened. Wound infections were found in 1.3% and symptomatic pseudarthroses 2.1% during follow up. A recurrent stenosis was the dominant reason for revision at 4.1% after 239 days (&#177; 318)12 (Table 2).
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Patient characteristics&#160;</td>
			<td>All (n=158)</td>
			<td>Trans-psoas (n=145)</td>
			<td>Pre-proas (n=13)</td>
		</tr>
		<tr>
			<td>Overall complications</td>
			<td>31 (19.6%)</td>
			<td>30 (20.7%)</td>
			<td>1 (7.7%)</td>
		</tr>
		<tr>
			<td>Temporary hip flexor weakness&#160;</td>
			<td>11 (7%)</td>
			<td>11 (8%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Significant Bleeding (&#62; 500 mL)&#160;</td>
			<td>4 (2.5%)</td>
			<td>4 (3%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Numbness (permanent)</td>
			<td>1 (0.6%)</td>
			<td>1 (1%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Nerve injury (permanent)</td>
			<td>1 (0.6%)</td>
			<td>1 (1%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Wound infection</td>
			<td>2 (1.3%)</td>
			<td>2 (1%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Recurrent stenosis&#160;</td>
			<td>11 (7.0%)</td>
			<td>6 (4.1%)&#160;</td>
			<td>2 (15.4%)</td>
		</tr>
		<tr>
			<td>Hardware failure&#160;</td>
			<td>4 (2.5%)</td>
			<td>4 (2.8%)&#160;</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Pseudarthrosis&#160;</td>
			<td>3 (1.9%)</td>
			<td>3 (2.1%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Adjacent level disease</td>
			<td>2 (1.3%)</td>
			<td>2 (1.4%)</td>
			<td>0</td>
		</tr>
		<tr>
			<td>Inability to place hardware&#160;</td>
			<td>1 (0.6%)</td>
			<td>1 (0.6%)</td>
			<td></td>
		</tr>
		<tr>
			<td>Days till revision&#160;</td>
			<td>221 (&#177; 22)</td>
			<td>239 (&#177;318)</td>
			<td>67 (&#177; 34)&#160;</td>
		</tr>
	</tbody>
</table>
Table 2: Complications and revision rates
At a mean follow-up time of 21.2 months, cage subsidence and pseudarthrosis were observed at 13.8% and 7.5%, respectively.

Interbody fusion of the lumbar spine can be achieved surgically using different techniques. Minimally invasive techniques, including lateral interbody fusion, have been developed within recent decades to reduce rates of complications and allow for quicker patient recovery. We provide insight into stand-alone lateral trans-psoas interbody fusion, highlighting potential complications and pitfalls.

Surgical Approach and Complications of Stand-alone Lateral Trans-Psoas Interbody Fusion

Interbody fusion of the lumbar spine is a standard procedure for symptomatic degenerative lumbar spine disease if conservative treatment fails. Surgical ...

surgical-approach-complications-stand-alone-lateral-trans-psoas

Nanyang Technological University

Research

JoVE Journal

Medicine

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Video: Chirurgische benadering en complicaties van stand-alone laterale trans-psoas interbodyfusie

A Novel Surgical Approach for Intratracheal Administration of Bioactive Agents in a Fetal Mouse Model

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and acquired diseases. Apart from congenital or inherited abnormalities with the requirement for long-term expression of the delivered gene, several non-inherited perinatal conditions, where short-term gene expression or pharmacological intervention is sufficient to achieve therapeutic effects, are considered as potential future indications for this kind of approach. Candidate diseases for the application of short-term prenatal therapy could be the transient neonatal deficiency of surfactant protein B causing neonatal respiratory distress syndrome1,2 or hyperoxic injuries of the neonatal lung3. Candidate diseases for permanent therapeutic correction are Cystic Fibrosis (CF)4, genetic variants of surfactant deficiencies5 and &alpha;1-antitrypsin deficiency6.
Generally, an important advantage of prenatal gene therapy is the ability to start therapeutic intervention early in development, at or even prior to clinical manifestations in the patient, thus preventing irreparable damage to the individual. In addition, fetal organs have an increased cell proliferation rate as compared to adult organs, which could allow a more efficient gene or stem cell transfer into the fetus. Furthermore, in utero gene delivery is performed when the individual's immune system is not completely mature. Therefore, transplantation of heterologous cells or supplementation of a non-functional or absent protein with a correct version should not cause immune sensitization to the cell, vector or transgene product, which has recently been proven to be the case with both cellular and genetic therapies7.
In the present study, we investigated the potential to directly target the fetal trachea in a mouse model. This procedure is in use in larger animal models such as rabbits and sheep8, and even in a clinical setting9, but has to date not been performed before in a mouse model. When studying the potential of fetal gene therapy for genetic diseases such as CF, the mouse model is very useful as a first proof-of-concept because of the wide availability of different transgenic mouse strains, the well documented embryogenesis and fetal development, less stringent ethical regulations, short gestation and the large litter size.
Different access routes have been described to target the fetal rodent lung, including intra-amniotic injection10-12, (ultrasound-guided) intrapulmonary injection13,14 and intravenous administration into the yolk sac vessels15,16 or umbilical vein17. Our novel surgical procedure enables researchers to inject the agent of choice directly into the fetal mouse trachea which allows for a more efficient delivery to the airways than existing techniques18.

We developed a novel surgical approach for intratracheal administration of bioactive agents into the mouse fetus. The delivery route is more efficient in targeting the fetal mouse lungs than the commonly used intra-amniotic injection. This procedure has to date not been described in a mouse model.

Prenatal pulmonary delivery of cells, genes or pharmacologic agents could provide the basis for new therapeutic strategies for a variety of genetic and ...

The Mouse Round-window Approach for Ototoxic Agent Delivery: A Rapid and Reliable Technique for Inducing Cochlear Cell Degeneration

Investigators have utilized a wide array of animal models and investigative techniques to study the mammalian auditory system. Much of the basic research involving the cochlea and its associated neural pathways entails exposure of model cochleae to a variety of ototoxic agents. This allows investigators to study the effects of targeted damage to cochlear structures, and in some cases, the self-repair or regeneration of those structures. Various techniques exist for delivery of ototoxic agents to the cochlea. When selecting a particular technique, investigators must consider a number of factors, including the induction of inadvertent systemic toxicity, the amount of cochlear damage produced by the surgical procedure itself, the type of lesion desired, animal survivability, and reproducibility/reliability of results. Currently established techniques include parenteral injection, intra-peritoneal injection, trans-tympanic injection, endolymphatic sac injection, and cochleostomy with perilymphatic perfusion. Each of these methods has been successfully utilized and is well described in the literature; yet, each has various shortcomings. Here, we present a technique for topical application of ototoxic agents directly to the round window niche. This technique is non-invasive to inner ear structures, produces rapid onset of reliably targeted lesions, avoids systemic toxicity, and allows for an intra-animal control (the contra-lateral ear). Results stemming from this approach have helped deeper understanding of auditory pathophysiology, cochlear cell degeneration, and regenerative capacity in response to an acute injury. Future investigations may use this method to conduct interventional studies involving gene therapy and stem cell transplantation to combat hearing loss.

Various methods exist for introducing ototoxic agents to the cochleae of animal models. Presented is a surgical protocol for delivery of ototoxic agents to the round window niche. The procedure is reliable, creates targeted intra-cochlear lesions, and avoids mechanical damage to the microarchitecture. Examination of cochlear self-repair/regeneration is possible.

Investigators have utilized a wide array of animal models and investigative techniques to study the mammalian auditory system. Much of the basic research ...

Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. ...

Three-dimensional Navigation-guided, Prone, Single-position, Lateral Lumbar Interbody Fusion Technique

Lateral interbody fusion provides a significant biomechanical advantage over the traditional transforaminal lumbar interbody fusion due to the large implant size and optimal implant position. However, current methods for lateral interbody cage placement require either a two-staged procedure or a single lateral decubitus position that precludes surgeons from having either full access to the posterior spine for direct decompression or comfortable pedicle screw placement.
Herein is one institution's experience with 10 cases of a prone single-position approach for simultaneous access to the anterior and posterior lumbar spine. This allows both lateral lumbar interbody cage placement, direct posterior decompression, and pedicle screw placement, all in one position. Three-dimensional (3D) navigation is utilized for increased precision in both approaching the lateral spine and interbody cage placement. The traditional blind psoas muscle tubular dilation was also modified. Tubular retractors and lateral vertebral body retractor pins were used to minimize the risks to the lumbar plexus.

The single-position, prone, lateral approach allows for both lateral lumbar interbody placement and direct posterior decompression with pedicle screw placement in one position.

Lateral interbody fusion provides a significant biomechanical advantage over the traditional transforaminal lumbar interbody fusion due to the large ...

Neuroscience

Posterior Approach for Debridement of the Psoas Abscess

This method focuses on outlining a safe zone for irrigation and debridement of a psoas abscess through a posterior approach. Initially, an anterior approach to the spine was performed to ensure that the anterior longitudinal ligament and the psoas muscle could be visualized. All the abdominal organs were removed. Subsequently, a posterior approach was performed to remove the paraspinal muscles from L1&#8211;L5. The transverse processes, pars interarticularis and lamina of L1&#8211;L5 were identified. The exiting nerve root was identified between the transverse processes and followed into the substance of the psoas muscle. Using the anterior and posterior approach, the lumbar plexus was isolated from the substance of the psoas muscle. Before and after various steps of dissection, digital photographs were obtained. These images were uploaded into ImageJ and multiple measurements, including the distance between the lateral superior and inferior tip of each TP to the most lateral region of the plexus, the distance between the lateral superior and inferior tip of the TP to the lateral edge of the psoas, and the width of the lumbar plexus were recorded. The safe zone for entering the substance of the psoas muscle was defined between the lateral edge of the psoas muscle and the lateral edge of the lumbar plexus. The relationship of this interval to the tip of the transverse process at each level was measured and reported.

This is a cadaveric study investigating the landmarks for the posterior approach for irrigation and debridement of the psoas abscess. The interval between the transverse processes (TP) was used to access the substance of the psoas muscle.

This method focuses on outlining a safe zone for irrigation and debridement of a psoas abscess through a posterior approach. Initially, an anterior ...

C-arm-Free Simultaneous OLIF51 and Percutaneous Pedicle Screw Fixation in a Single Lateral Position

Oblique lumbar interbody fusion (OLIF) is an established technique for the indirect decompression of lumbar canal stenosis. However, OLIF at the L5-S1 level (OLIF51) is technically difficult because of the anatomical structures. We present a novel simultaneous technique of OLIF51 with percutaneous pedicle screw fixation without fluoroscopy. The patient is placed in a right lateral decubitus position. A percutaneous reference pin is inserted into the right sacroiliac joint. An O-arm scan is performed, and 3D reconstructed images are transmitted to the spinal navigation system. A 4 cm oblique skin incision is made under navigation guidance along the pelvis. The internal/external and transverse abdominal muscles are divided along the muscle fibers, protecting the iliohypogastric and ilioinguinal nerves. Using a retroperitoneal approach, the left common iliac vessels are identified. Special muscle retractors with illumination are used to expose the L5-S1 intervertebral disc. After disc preparation with navigated instruments, the disc space is distracted with navigated trials. Autogenous bone and demineralized bone material are then inserted into the cage hole. The OLIF51 cage is inserted into the disc space with the help of a mallet. Simultaneously, percutaneous pedicle screws are inserted by another surgeon without changing the lateral decubitus position of the patient.
In conclusion, C-arm-free OLIF51 and simultaneous percutaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This novel technique reduces surgical time and radiation hazards.

C-arm-free oblique lumbar interbody fusion at the L5-S1 level (OLIF51) and simultaneous pedicle screw fixation are performed in a lateral position under navigation guidance. This technique does not expose the surgeon or operating staff to radiation hazards.

Oblique lumbar interbody fusion (OLIF) is an established technique for the indirect decompression of lumbar canal stenosis. However, OLIF at the L5-S1 ...

Application of Stand-Alone Oblique Lateral Interbody Fusion in L4-5 Lumbar Diseases

Lumbar spine diseases often cause lower back pain, lower extremity pain, numbness, and paresthesia. In severe cases, intermittent claudication may occur, affecting the quality of life of patients. Surgery is often required when conservative treatment fails, or when patients' symptoms become unbearable. Surgical treatments include laminectomy and discectomy, as well as interbody fusion. The main purpose of laminectomy and discectomy is to relieve nerve compression; however, recurrence is common due to spinal instability. Interbody fusion improves stability while relieving nerve compression and significantly reduces the risk of recurrence compared to non-fusion surgery. Nonetheless, conventionally posterior intervertebral fusion requires separation of the muscles to expose the operated segment, which causes more trauma to the patient. In contrast, the oblique lateral interbody fusion (OLIF) technique achieves spinal fusion with minimal trauma to the patients and shortens the recovery time. This article introduces procedures of stand-alone OLIF surgery performed in the lumbar spine, providing a reference for other spine surgeons.

This study describes the application of oblique lateral interbody fusion in lumbar spinal surgeries.

Lumbar spine diseases often cause lower back pain, lower extremity pain, numbness, and paresthesia. In severe cases, intermittent claudication may occur, ...

Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

The technique described in this article is well-suited to the Mini-ALIF procedure, allows for excellent exposure and decompression, and facilitates microscope-assisted manipulation.

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for ...

Oblique Lumbar Interbody Fusion at L5-S1 Segment Through an Approach Between the Psoas Muscle and the Great Vessels

Over the years, the oblique lateral interbody fusion (OLIF) technique has gained significant recognition for treating various spinal conditions in lumbar segments L2-L5. However, the adoption of OLIF for the L5-S1 segment has not been widely embraced by the spinal surgery community, given that significant concerns remain regarding the applicability of OLIF for lumbosacral fusion. In this study, a cohort of 20 patients underwent interbody fusion at the L5-S1 level using the OLIF technique through a single retroperitoneal oblique approach positioned between the Psoas muscle and the great vessels. The procedure involved discectomy and endplate preparation accomplished through a surgical window created on the anterolateral side of the L5-S1 disc. For secure interbody fusion cage placement, a supplementary cage insertion approach was employed. All patients were followed up for a minimum of 12 months. The mean preoperative visual analog scale (VAS) score for lower back pain was 6.3 &#177; 1.5 and experienced a significant reduction to 1.2 &#177; 0.8 at 12 months. The VAS score for lower limb pain significantly decreased from 5.6 &#177; 1.4 preoperatively to 0.8 &#177; 0.3 at 12 months after the surgery. Furthermore, the preoperative Oswestry disability index (ODI) improved from 82.4% &#177; 16.2% to 8.1% &#177; 2.0% at 12 months. Radiographic evaluations after surgery confirmed improved lumbosacral junction reconstruction for all patients. At the final follow-up, successful bony fusion was observed in all cases. Based on these findings, the OLIF technique for L5-S1 fusion represents an attainable approach for lumbosacral reconstruction. The procedure&#39;s success hinges on a comprehensive preoperative plan and precise intraoperative techniques.

The protocol presents an OLIF L5-S1 technique that offers a more feasible approach for lumbosacral fusion sharing a common surgical plane with OLIF L2-5. This facilitates reproducible multi-level interbody fusions extending from L2 to S1 through a retroperitoneal oblique corridor between the Psoas muscle and the great vessels.

Over the years, the oblique lateral interbody fusion (OLIF) technique has gained significant recognition for treating various spinal conditions in lumbar ...

Technique of Sagittal Adjusting Screw System for Thoracolumbar Burst Fractures

Minimally Invasive Treatment for Thoracolumbar Burst Fracture Using Sagittal Alignment Screws and A Trauma Reduction Device

Thoracolumbar (TL) burst fracture is one of the most common indications for minimally invasive percutaneous pedicle screw fixation. Although the indication for surgical treatment of neurologically intact TL fractures remains under debate, studies have demonstrated that posttraumatic malalignment may lead to a deterioration in the patient&#39;s quality of life. For burst fractures with malalignment or fragments in the spinal canal, a reduction technique using ligamentotaxis is commonly used to improve long-term outcomes.
The sagittal adjusting screw (SAS) system is a monoaxial screw system with a fixed head and concave sliding saddle that allows lordotic sliding of the rod in the sagittal plane after screw insertion. SAS also has a percutaneous option and has been used for TL spine fractures. Notably, the SAS only allows motion on the sagittal plane, allowing both secure fixation and angular reduction. The SAS has certain advantages over the conventional Schanz screw system or normal mono-/multiaxial pedicle screws for TL spine fracture treatment. In addition, specialized trauma reduction devices are available for the SAS system. In this video protocol, we discuss the indication for the SAS system in TL burst fracture and describe a technique of TL burst fracture reduction and fixation using the SAS system. Additionally, we describe our recent case series with radiological evaluation, including regional kyphotic angle and percent loss of anterior vertebral body height, to evaluate the newly introduced trauma reduction device.

The sagittal adjusting screw (SAS) system has been widely used for thoracolumbar (TL) spinal trauma. Percutaneous options and specialized trauma reduction devices are also available for the SAS system. We describe a technique for reducing TL burst fractures using an SAS system and a newly introduced trauma reduction device.

Surgical Approach and Complications of Stand-alone Lateral Trans-Psoas Interbody Fusion

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