| hasegawa TMD et al.1212. Hasegawa T, Mikawa Y, Watanabe R, An HS. Morphometric analysis of the lumbosacral nerve roots and dorsal root ganglia by magnetic resonance imaging. Spine (Phila Pa 1976). 1996;21(9):1005–9.
|
1996 |
MRI - 20 adults |
Vertebral pedicle |
The nerves that originate in L4L5 originate in the middle third of the pedicle (65%). |
The lumbar plexus of L1 to L5 begins more dorsally and at L4 begins its ventralization. |
| Moro T et al.1313. Moro T, Kikuchi S, Konno S, Yaginuma H. An anatomic study of the lumbar plexus with respect to retroperitoneal endoscopic surgery. Spine (Phila Pa 1976). 2003;28(5):423-8.
|
2003 |
Cadaver −30 adult cadavers |
The distance between the anterior and posterior margins of the vertebral body was divided into 4 equal zones (I, II, III, and IV). |
The lumbar plexus is located in zone II and below in L4L5. The genitofemoral nerve was found in zone I. |
The safe working zone is above L4L5, excluding the genitofemoral nerve (which is anteriorized before the others). |
| Benglis DM et al.22. Benglis DM, Vanni S, Levi AD. An anatomical study of the lumbosacral plexus as related to the minimally invasive transpsoas approach to the lumbar spine. J Neurosurg Spine. 2009;10(2):139–44.
|
2009 |
Cadaver - 3 adult cadavers |
The relationship between the location of the plexus in the posterior terminal plate and the total length of the disc in radiographical images. |
28% (L4L5) |
They suggest that the lumbar plexus begins more dorsally (L1L2) and has a more ventral direction during its course, especially in L4L5. Therefore, there is a higher risk of lesion of the genitofemoral nerve and the lumbar plexus. |
| Regev GJ et al.1515. Regev GJ, Chen L, Dhawan M, Lee YP, Garfin SR, Kim CW. Morphometric analysis of the ventral nerve roots and retroperitoneal vessels with respect to the minimally invasive lateral approach in normal and deformed spines. Spine (Phila Pa 1976). 2009;34(12):1330–5.
|
2009 |
MRI - 100 adults |
Anterior to posterior margin of the terminal plate of each vertebral disc. |
19.5mm |
The safety zone between L4 and L5 is quite reduced in comparison to the other vertebrae (13.1%). Thus, an error in posterior interventions could damage nerves or in anterior interventions, the blood vessels (particularly on the right). |
| Uribe JS et al.1616. Uribe JS, Arredondo N, Dakwar E, Vale FL. Defining the safe working zones using the minimally invasive lateral retroperitoneal transpsoas approach: an anatomical study. J Neurosurg Spine. 2010;13(2):260–6.
|
2010 |
Cadaver - 5 cadavers |
The space between the anterior and posterior margins of the vertebral body was divided into 4 equal zones. |
The lumbar plexus is ideally located in zones III and IV (L4L5) and the genitofemoral nerve was found in zone I. |
They suggest that the safe work zone would be in zone III (posterior middle fourth) and in L4L5 between zones II and III. |
| Guérin P et al.55. Guérin P, Obeid I, Gille O, Bourghli A, Luc S, Pointillart V, et al. Safe working zones using the minimally invasive lateral retroperitoneal transpsoas approach: A morphometric study. Surg Radiol Anat. 2011;33(8):665–71.
|
2011 |
MRI - 78 adults between 30 and 71 years of age. |
Dorsal region of the terminal plate of the vertebral body. |
No nerve root was found anterior to the terminal plate in 37.8%. |
The safe working zone is found in the most anterior part of the terminal plate (anterior to the nerves and posterior to the blood vessels). |
| Kepler KC et al.1414. Kepler CK, Bogner EA., Herzog RJ, Huang RC. Anatomy of the psoas muscle and lumbar plexus with respect to the surgical approach for lateral transpsoas interbody fusion. Eur Spine J. 2011;20(4):550–6.
|
2011 |
MRI - 43 adults above 50 years of age |
A coronal plane in each disc defined by the line that connects the anterior margin of the two adjacent vertebral bodies - anterior intervertebral plane (AIP). AIP to the lumbar plexus |
22.1mm (L4L5) |
The anterior edge of the psoas major muscle should be used as a reference to estimate the position of the lumbar plexus - when the anterior edge of the psoas muscle is 10 mm anterior to the AIP, the position of the lumbar plexus will be approximately 20 mm posterior to the AIP. Patients with neurological structures at risk were defined as those who had lumbar plexus/femoral nerve less than 20 mm from the anterior intervertebral plane. |
| Lu S et al.1717. Hu WK, He SS, Zhang SC, Liu YB, Li M, Hou TS, et al. An MRI study of psoas major and abdominal large vessels with respect to the X/DLIF approach. Eur Spine J. 2011;20(4):557–62.
|
2011 |
Cadaver −15 cadavers from 56 to 87 years of age |
Lower level of the transverse process. Division of the psoas major muscle into 3 equal thirds. |
4.9 - 8.4 mm (L4L5) Posterior third |
The psoas muscle can be considered a surgical marker, and incisions should be made in the anterior 2/3. |
| Spivak JM et al.1818. Spivak JM, Paulino CB, Patel A, Shanti N, Pathare N. Safe zone for retractor placement to the lumbar spine via the transpsoas approach. J Orthop Surg (Hong kong). 2013;21(1):77–81.
|
2013 |
Cadaver - 12 adults between 35 and 74 years of age. |
Anterior posterior diameter of each vertebral body (measured between the anterior edge of the foramen and the anterior edge of the vertebral body). |
No nerve roots were found in the anterior 33% of the L4L5 intervertebral space. |
The safe working zone would be the anterior half of the intervertebral disc. |
