scholarly journals Retroperitoneal oblique corridor to the L2–S1 intervertebral discs: an MRI study

2016 ◽  
Vol 24 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Diana M. Molinares ◽  
Timothy T. Davis ◽  
Daniel A. Fung
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Vertebral Body ◽  
Psoas Muscle ◽  
Intervertebral Discs ◽  
Mr Images ◽  
Disc Space ◽  
Iliac Vessel ◽  
Medial Border ◽  
Transpsoas Approach

OBJECT The purpose of this study was to analyze MR images of the lumbar spine and document: 1) the oblique corridor at each lumbar disc level between the psoas muscle and the great vessels, and 2) oblique access to the L5–S1 disc space. Access to the lumbar spine without disruption of the psoas muscle could translate into decreased frequency of postoperative neurological complications observed after a transpsoas approach. The authors investigated the retroperitoneal oblique corridor of L2–S1 as a means of surgical access to the intervertebral discs. This oblique approach avoids the psoas muscle and is a safe and potentially superior alternative to the lateral transpsoas approach used by many surgeons. METHODS One hundred thirty-three MRI studies performed between May 4, 2012, and February 27, 2013, were randomly selected from the authors’ database. Thirty-three MR images were excluded due to technical issues or altered lumbar anatomy due to previous spine surgery. The oblique corridor was defined as the distance between the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5–S1 oblique corridor was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel (axial view) and vertically to the first vascular structure that crossed midline (sagittal view). RESULTS The oblique corridor measurements to the L2–5 discs have the following mean distances: L2–3 = 16.04 mm, L3–4 = 14.21 mm, and L4–5 = 10.28 mm. The L5–S1 corridor mean distance was 10 mm between midline and left common iliac vessel, and 10.13 mm from the first midline vessel to the inferior endplate of L-5. The bifurcation of the aorta and confluence of the vena cava were also analyzed in this study. The aortic bifurcation was found at the L-3 vertebral body in 2% of the MR images, at the L3–4 disc in 5%, at the L-4 vertebral body in 43%, at the L4–5 disc in 11%, and at the L-5 vertebral body in 9%. The confluence of the iliac veins was found at lower levels: 45% at the L-4 level, 19.39% at the L4–5 intervertebral disc, and 34% at the L-5 vertebral body. CONCLUSIONS An oblique corridor of access to the L2–5 discs was found in 90% of the MR images (99% access to L2–3, 100% access to L3–4, and 91% access to L4–5). Access to the L5–S1 disc was also established in 69% of the MR images analyzed. The lower the confluence of iliac veins, the less probable it was that access to the L5–S1 intervertebral disc space was observed. These findings support the use of lumbar MRI as a tool to predetermine the presence of an oblique corridor for access to the L2–S1 intervertebral disc spaces prior to lumbar spine surgery.

Retroperitoneal oblique corridor to the L2–S1 intervertebral discs in the lateral position: an anatomic study

2014 ◽  
Vol 21 (5) ◽  
pp. 785-793 ◽  
Author(s):  
Timothy T. Davis ◽  
Richard A. Hynes ◽  
Daniel A. Fung ◽  
Scott W. Spann ◽  
Michael MacMillan ◽  
...  
Keyword(s):  
Intervertebral Discs ◽  
Lateral Decubitus Position ◽  
Lumbar Plexus ◽  
Intervertebral Disc Space ◽  
Disc Space ◽  
Static State ◽  
Iliac Vessel ◽  
Mean Values ◽  
Medial Border ◽  
Lateral Decubitus

Object Access to the intervertebral discs from L2–S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4–5 disc access, and the L5–S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2–S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus. Methods Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2–S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2–5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5–S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline. Results The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2–3, 18.60 mm and 25.50 mm; at L3–4, 19.25 mm and 27.05 mm; and at L4–5, 15.00 mm and 24.45 mm. The L5–S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel. Conclusions The oblique corridor allows access to the L2–S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5–S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2–S1 discs.

An anatomical study of the lumbosacral plexus as related to the minimally invasive transpsoas approach to the lumbar spine

2009 ◽  
Vol 10 (2) ◽  
pp. 139-144 ◽  
Author(s):  
David M. Benglis ◽  
Steve Vanni ◽  
Allan D. Levi
Keyword(s):  
Lumbar Spine ◽  
Minimally Invasive ◽  
Interbody Fusion ◽  
Psoas Muscle ◽  
Anatomical Study ◽  
Lumbosacral Plexus ◽  
Disc Space ◽  
Lateral Interbody Fusion ◽  
Transpsoas Approach ◽  
Lateral Interbody

Object Minimally invasive anterolateral approaches to the lumbar spine are options for the treatment of a number of adult degenerative spinal disorders. Nerve injuries during these surgeries, although rare, can be devastating complications. With an increasing number of spine surgeons utilizing minimal access retroperitoneal surgery to treat lumbar problems, the frequency of complications associated with this approach will likely increase. The authors sought to better understand the location of the lumbar contribution of the lumbosacral plexus relative to the disc spaces encountered when performing the minimally invasive transpsoas approach, also known as extreme lateral interbody fusion or direct lateral interbody fusion. Methods Three fresh cadavers were placed lateral, and a total of 3 dissections of the lumbar contribution of the lumbosacral plexus were performed. Radiopaque soldering wire was then laid along the anterior margin of the nerve fibers and the exiting femoral nerve. Markers were placed at the disc spaces and lateral fluoroscopy was used to measure the location of the lumbar plexus along each respective disc space in the lumbar spine (L1–2, L2–3, L3–4, and L4–5). Results The lumbosacral plexus was found lying within the substance of the psoas muscle between the junction of the transverse process and vertebral body and exited along the medial edge of the psoas distally. The lumbosacral plexus was most dorsally positioned at the posterior endplate of L1–2. A general trend of progressive ventral migration of the plexus on the disc space was noted at L2–3, L3–4, and L4–5. Average ratios were calculated at each level (location of the plexus from the dorsal endplate to total disc length) and were 0 (L1–2), 0.11 (L2–3), 0.18 (L3–4), and 0.28 (L4–5). Conclusions This anatomical study suggests that positioning the dilator and/or retractor in a posterior position of the disc space may result in nerve injury to the lumbosacral plexus, especially at the L4–5 level. The risk of injuring inherent nerve branches directed to the psoas muscle as well as injury to the genitofemoral nerve do still exist.

scholarly journals Convergence analysis and validation of a discrete element model of the human lumbar spine

2022 ◽  
Vol 3 (1) ◽  
pp. 62-70
Author(s):  
Galina Eremina ◽  
◽  
Alexey Smolin ◽  
Irina Martyshina ◽  
◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Bone Tissue ◽  
Vertebral Body ◽  
Loading Rate ◽  
Numerical Models ◽  
Fold Increase ◽  
Intervertebral Discs ◽  
Effective Stiffness ◽  
Structural Element

Degenerative diseases of the spine can lead to or hasten the onset of additional spinal problems that significantly reduce human mobility. The spine consists of vertebral bodies and intervertebral discs. The most degraded are intervertebral discs. The vertebral body consists of a shell (cortical bone tissue) and an internal content (cancellous bone tissue). The intervertebral disc is a complex structural element of the spine, consisting of the nucleus pulposus, annulus fibrosus, and cartilaginous plates. To develop numerical models for the vertebral body and intervertebral disc, first, it is necessary to verify and validate the models for the constituent elements of the lumbar spine. This paper, for the first time, presents discrete elements-based numerical models for the constituent parts of the lumbar spine, and their verification and validation. The models are validated using uniaxial compression experiments available in the literature. The model predictions are in good qualitative and quantitative agreement with the data of those experiments. The loading rate sensitivity analysis revealed that fluid-saturated porous materials are highly sensitive to loading rate: a 1000-fold increase in rate leads to the increase in effective stiffness of 130 % for the intervertebral disc, and a 250-fold increase in rate leads to the increase in effective stiffness of 50 % for the vertebral body. The developed model components can be used to create an L4-L5 segment model, which, in the future, will allow investigating the mechanical behavior of the spine under different types of loading.

Disc space-targeted angled axial MR images of the lumbar spine: a potential source of diagnostic error

2007 ◽  
Vol 36 (12) ◽  
pp. 1147-1153 ◽  
Author(s):  
Kush Singh ◽  
Clyde A. Helms ◽  
David Fiorella ◽  
Nancy A. Major
Keyword(s):  
Lumbar Spine ◽  
Diagnostic Error ◽  
Mr Images ◽  
Disc Space ◽  
Potential Source

scholarly journals Variability in the size of the retroperitoneal oblique corridor: A magnetic resonance imaging-based analysis

2020 ◽  
Vol 11 ◽  
pp. 54
Author(s):  
Zain Boghani ◽  
William III Steele ◽  
Sean M. Barber ◽  
Jonathan J. Lee ◽  
Olumide Sokunbi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Lumbar Spine ◽  
Magnetic Resonance ◽  
Psoas Muscle ◽  
Resonance Imaging ◽  
Medial Aspect ◽  
Disc Space ◽  
Invasive Approach ◽  
Major Vessel ◽  
Iliac Bifurcation

Background: A minimally invasive approach to the L2-S1 disc spaces through a single, left-sided, retroperitoneal oblique corridor has been previously described. However, the size of this corridor varies, limiting access to the disc space in certain patients. Here, the authors retrospectively reviewed lumbar spine magnetic resonance imaging (MRI) in 300 patients to better define the size and variability of the retroperitoneal oblique corridor. Methods: Lumbar spine MRI from 300 patients was reviewed. The size of the retroperitoneal oblique corridor from L2-S1 was measured. It was defined as the (1) distance between the medial aspect of the aorta and the lateral aspect of the psoas muscle from L2-L5 and (2) the distance between the midpoint of the L5-S1 disc and the medial aspect of the nearest major vessel on the left at L5-S1. In addition, the rostral-caudal location of the iliac bifurcation was measured. Results: The size of the retroperitoneal oblique corridor at L2/3, L3/4, L4/5, and L5/S1 was, respectively, 17.3 ± 6.4 mm, 16.2 ± 6.3 mm, 14.8 ± 7.8 cm, and 13.0 ± 8.3 mm. The incidence of corridor size <1 cm at L2/3, L3/4, L4/5, and L5/S1 was 10.3%, 16.0%, 30.0%, and 39.3%, respectively. The iliac bifurcation was most commonly found behind the L4 vertebral body (n = 158, 52.67%) followed by the L4/5 disc space (n = 74, 24.67%). Conclusion: The size of the retroperitoneal oblique corridor diminishes in a rostral-caudal direction, often limiting access to the L4/5 and L5/S1 disc spaces.

scholarly journals RESEARCH ON THE INFLUENCE OF THE PROPERTIES OF INTERVERTEBRAL DISC STIFFNESS OF THE LUMBAR SPINE ON THE DISPLACEMENT OF VERETBRAE / STUBURO JUOSMENINĖS DALIES TARPSLANKSTELINIO DISKO STANDUMO CHARAKTERISTIKŲ ĮTAKOS SLANKSTELIŲ POSLINKIAMS TYRIMAS

2015 ◽  
Vol 6 (6) ◽  
pp. 595-597
Author(s):  
Artūras Linkel ◽  
Julius Griškevičius ◽  
Gintaras Jonaitis
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Degrees Of Freedom ◽  
Angular Displacement ◽  
Fast Response ◽  
Intervertebral Discs ◽  
Linear Displacement ◽  
Basic Task ◽  
Non Linear ◽  
Solid Bodies

The article proposes the method for evaluating angular and linear changes in intervertebral discs of the spine depending on linear and nonlinear intervertebral disc stiffness. A dynamic made of 5 solid bodies connected by damping and stiffness components and applied for 2-D 10 degrees of freedom of the lumbar spine has been used for calculations. The system of the equation has been written in a matrix form. Lumbar intervertebral discs stiffness and damping properties have been selected from scientific articles and make from 200 N/mm to 1200 N/mm and from 229 Ns / mm to 5100 Ns/mm respectively for non-linear calculation and 800 N / mm – 2637 Ns/mm for linear displacement calculation. External loads applied to the model are 1648 N, 2957 N, 3863 N and 4542 N. The basic task of the paper is to calculate the biggest difference in linear and angular displacement considering 2 cases: linear and non-linear stiffness value. The greatest estimated difference, under the highest load, makes 0.6 mm for linear and 0.95 degrees for angular displacement. Because of the fast response of the model to the load, the damping value could not affect displacement. Tyrimo objektas yra stuburo trapslankstelinių diskų poslinkių skirtumai esant tiesiniam ir netiesiniam jų standumo koeficientui. Taikomas 10 laisvės laipsnių 2-D stuburo juosmeninės dalies dinaminis modelis, kuris susideda iš 5 juosmens slankstelių, sujungtų standumo ir slopinimo ryšiais. Modeliui nustatomos juosmens apkrovos, kurios susidaro važiuojant dviračiu. Tarpslankstelinių diskų savybės parenkamos iš mokslinės literatūros. Sudarytas matematinis modelis leido apskaičiuoti stuburo slankstelių linijinius ir kampinius poslinkius įvertinant tarpslankstelinio disko standžio netiesiškumą. Atlikti skaičiavimai parodė, kad didžiausi skirtumai susidaro esant maksimaliai apkrovai. Didžiausi linijinių poslinkių skirtumai yra 0,6 mm, o kampinių – 0,95 laipsnio. Nustatytos slopinimo koeficiento reikšmės dėl greito modelio atsako poslinkių skaičiavimams įtakos neturėjo.

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