Extreme Lateral EX Interbody Fusion

General

Transpsoas
Far lateral interbody fusion

Introduced in 2006

IOM: Lumbar plexus and genitofemoral nerves.

if IOM shows deficit change location of needle/retractor.

Indications

From L4/5 and cranial (Not L5/S1) + any TL spine case with need of access to disc and vertebral body

Adjacent segment degeneration
Degenerative disc disease (DDD) with instability
Recurrent disc herniation
Degenerative spondylolisthesis

Grade 1/2 only

High grades

The listhesis does not allow enough space for the docking of the retractor safely onto the disc space.
The lumbar plexus is brought forwards increases risk of injury to the lumbar plexus

Post-laminectomy DDD w/instability
Degenerative scoliosis
Pseudarthrosis
Corpectomy (tumor/trauma)
Anterior column realignment
Discitis

Surgical anatomy

Pre op scan review

X ray

Identify the ribs 11, 12

Identify Iliac crest

L4/5 can be done if the iliac crest is at the level of mid L4 vertebral body and below.

Address L4-L5 disk space with angled instruments-NOT by table break

MRI

Look at retroperitoneal fat

If doing higher levels check that there is fat around the kidneys so that it can be push forward for docking on the disc space

If not fat around kidneys could mean either

Patient is thin
Previous surgery in retroperitoneal space causing scaring

Look at psoas

Psoas is small cranially but increases to the size of the vertebral body at L4/5

The lumbar plexus

Transitional anatomy to look out for where at L4/5 the psoas is so large it is more anterior than the vertebral body. This also means that the lumbar plexus which is hyperintense on T2 within the psoas which is normally in the posterior 1/2 of the psoas, is now positioned in the anterior 1/2 of the psoas

The L4/5 is transitional and the psoas is larger and therefore the lumbar plexus is more anterior. Best to use a different interbody technique

L4/5 level where the psoas is the same size as the vertebral body

Look at Iliac arteries and veins

Make sure they are anterior to the vertebral body

Make sure they are not located laterally and between the psoas and vertebral body

This is important even on the contralateral side as annulotomy of the deep side can damage these vessels

Look at facet join

Look for fluid in the joint to suggest instability which suggest that there is scope for indirect decompression

Look for locked facet (over grown)

Meaning needs direct decompression

Choosing levels and side of surgery

Side of surgery

If there is fat under the blood vessel the vessel would be mobile

The plexus is not too anterior within the psoas

The vessel is on the right side so the left is safer

Where the bowel is located

Coronal scoliosis: check where the location

Side of leg pain: go to the side where the leg pain is worse to reduce risk of causing bilateral leg weakness or leg pain

Cranio-caudal

L4/5 can be done if the iliac crest is at the level of mid L4 vertebral body and below.

Address L4-L5 disk space with angled instruments-NOT by table break

Easiest is L2/3 and L3/4

Not for L5/S1

Cranially the T12 does not limit access as it is posterior to the disc space.

The T11 rib will obstruct.

Make an incision below T11 and use finger dissect through the diaphragm and sweep and push the pleura cranially to create space. After this make an incision between the 10 and 11 rib. can take rib down or push the ribs apart to get access to the disc space.

Contraindications

Patients with severe osteoporosis

Collapsed or fused disc space

Patients with general infections

Previous renal surgery

Anesthetic and neuromonitoring

TIVA, no paralytics

Make sure the MEP and EMG is working

Theatre set up

This is the theatre set up for a left sided ExLIF

Surgeon stands at the back of the patient

II base infront of the patients

Anesthetic team at the head.

monitoring at the top and anterior to the patient

So that surgeon can visualize both the Monitoring and II screen

Bed set up

Bed is turned 180 degree and move the head end and insert it to the end of the bed
Get a narrow table to make it easy for C arm to move

Position

Right lateral decubitus position

left side elevated
Patient position

Place the breaking point of the bed between the greater trochanter and the iliac crest.
Patient is kept as close to the edge of the bed

easier for surgeon to look down into the dept of the surgical field
This position keeps the bed rail from interfering with the C-arm images

Bend the hip and knees by 90 deg to:

Keep psoas lax
Creates increased stability of the patient preventing body roll.

The table and patient are laterally flexed to open the space between the iliac crest and the 12th rib.

Place two towel roll at the

Axillae: protect the brachial plexus
Waist: between the contralateral rib and iliac crest

Place two pillows between arms

Place one pillow between knees

The II is placed so that it is (do not change the angle of the II, only move the bed to get true lateral and true AP)

Parallel to the floor
90 deg to the floor

Adjust bed by tilting cranial caudal or laterally to make sure we have a true lateral x-ray

AP fluoroscopic image to confirm true AP

End plate is straight

AP x-ray done in lateral position shows that the spinous process is middle between two pedicle

Lateral x-ray done to make sure true lateral is shown

The exiting foramen is clearly seen

End plate is straight

Tilt so that the disc of interest is 90 deg to the floor

Tape

Before taping make sure true lateral is obtained first
1st just caudal to iliac crest

To keep skin taut
To make sure the tape do not losen when bed is broken

2nd X shaped tape

Start from greater trochanter → calf → under bed and across → corner of bed → over calf → under bed

3rd at Chest at nipple

Get a C arm to check you have a true AP before taping the chest

4th straight across calf

to prevent leg kicking during EMG stimulation

At the end of positioning the skin over lying the flank needs to be taut enough to be straight when a horizon view is taken but soft enough that when the skin is palpated the skin can be indented.

This is to allow the 3 abdominal muscle to be easily split

Attach the clamp for the retractor holder anterior to patient at the level of the thoracic spine.

Patient place so that GT is at the breakage point and a bit of the iliac crest is above the break

Mark skin

Mark out

Iliac crest

the more cranial looking one is the contralateral one. Mark the more caudal one

Ribs (11 and 12)

12 rib is hard to see as it is more vertical and should not block entry to disc space
A. The 12th rib is short as compared to the others and is normally positioned behind L2-L3 bodies on lateral fluoro.
B. The 11th rib can usually be found by crossing diagonally across the L1-L2 disc.

Lateral border of the ipsilateral erector spinae muscle

Anterior border of vertebral body (ALL)

Posterior border of vertebral body (PLL)

Mid point of the disc space

When drawing this line extending much anterior and posteriorly.

The angle of this line will tell you the direction of the AP xray to be done (to help guide the radiographer)

The line between the ALL and PLL will be the lateral incision point

Triangular area

Borders: Iliac crest, Ribs lateral border of ipsilateral erector spinae muscle.
Safe corridor for dissection to get under the abdominal wall muscle.

Mark out the posterior lateral incision

this will be within the triangular zone
It is at the MCP joint of the surgeons finger when the tip of the index finger is located at the posterior 1/3 of the disc space

Skin incision

Two options

Single incision technique (Dr Tan)

Make sure skin over lying the incision is taut enough so that the skin and underlying muscle can be split easily and the muscle fibres are easily visible
Horizontal incision made in line with the skin marking.

From ALL to PLL

Monopolar through the subcut fat but not any deeper due to the iliohypogastric and ilioinguinal nerves
Place retractors in to expose the External oblique fascia
Stand at the leg end of the patient, use artery forceps to open up the fascia and split the external oblique muscle.
Then split open the internal oblique followed by the transverse abdominus

One can tell the difference in the muscle by the orientation of the muscle fibres

The transverse abdominus fascia can be split using the artery and one will feel a drop into an empty space with fat.

Two incision technique

Posterior lateral incision

Made as wide to fit the whole index finger
Use finger and a closed dissecting scissor to blunt dissect between the quadratus lumborum and external oblique.

Do not enter the quadratus lumborum muscle as it will make dissection very difficult.

Open the dissecting scissor to widen the muscle opening for all 3 muscle fascia.
Now one enter the retroperitoneal fat area
Palpate for the ilium and sweep the peritoneum anteriorly.
Palpate for the TP and then the psoas which is located at the floor of the incision.

In more cranial cases: feel for the T11 rib and the diaphragm

A finger is inserted in this incision to tent up the . transversalis facia. Then guide the lateral skin incision so that the abdominal muscle can be split

Direct lateral incision made between the ALL and PLL

Go through skin and fat but do not enter the muscle until the finger is placed under the transverse abdominius muscle
Is the working incision
Split the muscle using scissor along the direction of the muscle fibres

External oblique
Internal oblique
Transverse abdominious

Trans-psoas dissection

Free run: Generally under GA, muscle does not produce any signal. However intraoperative irritation (Hammering, rubbing) can stimulate the muscle
Triggered:

Stimulation via electrical activity
help determine nerve presence, proximity, continuity, and prognosis of function.

Place the initial dilator and stimulate try to find the anterior femoral nerve, as the initial dilator traverse the psoas muscle.

Make sure the initial dilator is anterior to the femoral nerve and is > 10mA away from the nerve
Stimulation should be directed posteriorly where the femoral nerve is the closest

The holder should be as close to skin as possible to prevent slipping

If there is positive nerve stimulation or the nerve is anterior to the dilator 01or xray shows that it is not middle of the disc space or the 2/4-posterior 3/4 part of the disc space, take the dilator out and replaced it on the surface of the psoas before dissecting into the psoas again.

Use the initial dilator to position it 90 deg to the psoas and get it at the middle (both anterior/posteriorly and superior/inferiorly) overlying the disc.

Use Xray to confirm this

Place a sharp long K wire through the Psoas within the initial dilator into the disc.

Make sure that the needle is in the middle of the disc and that on AP xray it has passed over the midline. (check IOM)

Push the initial dilator down just outside of the disc space and also place the external dilator over it so that both dilator is sitting on the disc space but it is docked over the vertebral body. (check IOM)

Place the retractor over the dilator and get it within the muscle. (check IOM)

Place the initial dilator is in the psoas muscle

Here the tip is too posterior. How is the end of the dilator is identified: the proximal tip is always smaller and the distal is larger. The proximal tip has the stimulator clip located in.

Retractor placement

With the closed distal end of the retractor over the dilators, lower into the patient (once at the psoas, use neuromonitoring).

Take a fluoro image to confirm position (look for the "snake eyes" at the end of the retractor).

Reference line drawn (angle of disc space) and rotate the retractor so the line bisects the MaXcess retractor handles.

With the retractor oriented to the operative segment, connect the rigid arm to the MaXcess retractor.

Open retractor (check IOM)

the retractor can have 3 or 4 leafs

Two anterior and posterior
Two Medial and lateral

The retractor can have two pins that can be inserted into the upper and lower vertebrae to stabilize the retractor OR use a table stabilizer/holder

Efficiency

Time of retraction MOST IMPORTANT factor correlating with neurologic symptoms postop
Uribe et al (Eur Spine Journal 2015)

<30 minutes retraction time = less neuro comp risk

Discectomy

Perform the discectomy using the Osteotome, disc shaver, and then rasper.

Make sure that you are 90 degrees to the floor at all time so that we wont end up anterior (Aorta and IVC) or posterior (canal and cord)

Make sure to get across to the contralateral side of the disc by puncturing the annulus with a Cobb and gentle pressure.

Implantation

Gentle distraction of the disc space without damage the end plate

Measure the cage

The cage ideally needs to sit over the rim of the Endplate where it is the strongest.

Cage selection

Most commonly used width is 22 mm.
The height and shape of the implant depend on many factors:

Previous height of the disc space
Osteophytes
Condition of facet joints
Deformities

Cage filled with bone graft

Cage insertion

The use of correctly sized cages that reach the contralateral ring apophysis is recommended.

important to strike the cage inserter properly until the desired position is reached

A heavy impact can damage the endplate, causing subsidence of the cage.

If when placing the trial cage it suddenly felt very loose could be 3 things:

Trial cage in abdomen
Trial cage in vertebral body
ALL is torn

Post op plan

For the first month after surgery, it is recommended that a brace is used to reduce the movements of the lumbar spine.

Tips and tricks

Work in concavity of scoliosis so the disc space is all facing you and you can work though one incision

If doing multiple levels do the cranial one first as when you add disc height the cranial vertebrae will move away from the surgical field

At L4/5

One do not absolutely need to be perpendicular to the disc space.
One can used angled instruments
At T12/L1 one can put the shim into the disc space and angle the retractor cranially as the T12 ribs will move away

Relaxation of psoas muscle/plexus

Minimize or use minimal table break
Flex hip 30° and knees 90°
If necessary, address L4–L5 disc space with angled instruments, not by table break

Complication

Ghandi 2025

Complication	Prepsoas Studies (n = 20)	ㅤ	ㅤ	Transpsoas Studies (n = 39)	ㅤ	ㅤ	P value
ㅤ	No. Of events	Total no. Of pts	Incidence, % (95% CI)	No. Of events	Total no. Of pts	Incidence, % (95% CI)	ㅤ
Transient thigh or groin numbness/pain	93	1795	8.7 (4.9-15.0)	680	2352	21.7 (17.227.0)	0.002
Transient hip flexor weakness	18	1672	5.7 (3.9-8.2)	262	1295	19.7 (14.6-26.0)	0.001
Permanent motor neurological deficit [permanent neurological weakness]	9	1801	1.0 (0.5-1.8)	43	2842	2.8 (1.9-4.0)	0.005
Sympathetic plexus injury	11	412	5.4 (2.2-12.6)	0	641	0.0 (0.0-3.2)	0.03
Major vascular injury	21	1772	1.8 (0.9-3.5)	5	2709	0.4 (0.2-1.0)	0.01
Peritoneal (bowel) injury	3	1772	1.9 (0.6-5.5)	3	1655	1.3 (0.5-3.8)	0.64
Urological injury (kidney, ureter)	1	1772	1.1 (0.3-3.9)	0	1655	0.0 (0.0-0.9)	0.05
Postop ileus	16	1453	3.3 (1.0-10.2)	15	1199	2.8 (1.3-5.9)	0.79
Infection	10	1766	1.1 (0.6-2.0)	13	1807	3.1 (1.9-5.1)	0.01
Hematoma (psoas, subcutaneous)	14	1398	1.5 (0.9-2.5)	5	1196	1.7 (0.7-3.9)	0.13
Subsidence	56	241 (566*)	12.2 (5.6-24.7)	201	761 (1537*)	13.8 (9.4-19.7)	0.78
Pseudarthrosis	24	120 (262*)	9.9 (4.1-21.7)	103	796 (1275*)	7.5 (4.9-11.4)	0.57

Rodgers 2011

Nerve injury

Complication	No. of Events	Total No. of Pts	Incidence, % (95% CI)
Transient thigh or groin numbness/pain	680	2352	21.7 (17.2–27.0)
Transient hip flexor weakness	262	1295	19.7 (14.6–26.0)
Permanent motor neurological deficit	43	2842	2.8 (1.9–4.0)
Sympathetic plexus injury	0	641	0.0 (0.0–3.2)

Lumbar plexus injury

Mainly anterior thigh leg weakness, numbness

Generally due to swelling of the psoas causing transient femoral nerve deficit

If one can see the nerve, one is more likely to cause traction neuropraxia to the nerve

can take weeks to months to recover
Use the direct nerve probe to test the nerve throughout the case. Initially the nerve would be stimulated <5mA. Later on during the case if there is injury to the nerve then the stimulation will drop since the nerve is not functioning. If you see this during the case just remove the retractor and give time for the nerve to recover.

Very rare transect the nerve

Safe zone to prevent nerve injury

Requires thorough knowledge of lumbar plexus anatomy.

"Safe zones" defined for entry, typically anterior to the lumbar plexus within the psoas muscle.

The genitofemoral nerve, a sensory nerve, is ventral to Zone 3.

The “safe zone” (zone III) is depicted in green and is the recommended trajectory through the psoas to reduce lumbar plexus and femoral nerve injury.

Lumbar plexus injuries. Ahmadian 2012

A: Anterior views demonstrating a lateral abdominal hernia found 6 weeks postoperatively. Findings were associated with anesthesia of the superior-lateral portion of SDZ I.
B: Anterior view demonstrating significant muscle atrophy of the right lower extremity evident 18 months postoperatively, with associated anesthesia of SDZ III consistent with complete femoral nerve injury.
C: Lateral view outlining postoperative anesthesia (SDZ II) consistent with LFCN injury.
D: Anterior view outlining complex combined lumbar plexus injury with dermal anesthesia of SDZ II, paresthesia of SDZ III (sparing the saphenous dermatome), and neuropathic inguinal allodynia and regional anesthesia of SDZ I.
E: Lateral view demonstrating anesthesia of the lateral portion of SDZ I consistent with injury to the lateral cutaneous branch of the iliohypogastric nerve.

Sensory dermal zone (SDZ) -Ahmadian 2012

Nerves	Cutaneous/Sensory innervation	Motor innervation	Clinical syndrome	Injured
iliohypogastric	ant/lat cutaneous branches	transversus abdominis, internal oblique	Zone I	Approach through the abdominal wall
ㅤ	lower abdomen/mons pubis/upper gluteal	ㅤ	ㅤ	ㅤ
ilioinguinal	ant scrotal/labial branches (male/female)	transversus abdominis, internal oblique	Zone I	Approach through the abdominal wall
ㅤ	labium majus/scrotum sensation	ㅤ	(+/−) loss of cremasteric reflex	ㅤ
ㅤ	upper medial thigh sensation	ㅤ	ㅤ	ㅤ
subcostal	lower abdomen/flank	rectus abdominis, external oblique	Zone I	Approach through the abdominal wall
genitofemoral	genital branch	cremaster	Zone I	Approach through the abdominal wall
ㅤ	labium majus/scrotum sensation	ㅤ	(+/−) loss of cremasteric reflex	ㅤ
ㅤ	femoral/lumboinguinal branch	ㅤ	ㅤ	ㅤ
ㅤ	upper anteromedial thigh sensation	ㅤ	ㅤ	ㅤ
LFCN	lat thigh sensation	none	Zone II	Aggressive dissection of the retroperitoneal adipose tissue.
obturator	cutaneous branch	adductor longus, adductor magnus, obturator externus, gracilis, pectineus	Zone IV	On the psoas
ㅤ	lower medial thigh sensation	ㅤ	(+) leg adduction	ㅤ
femoral	ant cutaneous branches	iliopsoas, pectineus, sartorius, quadriceps femoris	Zone III	On the psoas and dissection of retroperitoneal fat
ㅤ	anteromedial thigh/leg sensation	ㅤ	(+) loss of patellar reflex	ㅤ
ㅤ	saphenous	ㅤ	(+) hip flexor weakness	ㅤ
ㅤ	medial leg sensation	ㅤ	(+) knee extension weakness	ㅤ
ㅤ	ㅤ	ㅤ	(+) lat thigh rotation	ㅤ

SDZ I—iliohypogastric, illioinguinal, genitofemoral, and subcostal nerves

SDZ II—LFCN

SDZ III—femoral nerve;

SDZ IV—obturator nerve.

Diagnostic paradigm for lumbar plexopathy. Interval electrodiagnostic studies for weakness without clinical recovery are performed at 6 weeks and 3 months (asterisks), and then at intervals thereafter to evaluate for reinnervation. Motor deficits with initial strength greater than antigravity have the potential for good functional recovery with physical therapy (suspected partial neurapraxia). No definitive conclusion on prognosis can be made from initial plegia. A degree of improvement is expected within 3 months with neurapraxia as opposed to axonotmesis or neurotmesis. FN = femoral nerve; LFC = LFCN; ON = obturator nerve.

Genitofemoral nerve injury

Burning or shooting pain, but it may also present as itching, tingling, stabbing, or sharp pain

Most common are transient thigh symptoms (numbness, paresthesias, dysesthesias) (0%-75%).

Femoral nerve and other motor injuries are less common (0.7%-33.6%), with a systematic review finding 2.8% permanent motor neurological deficit for ExLIF vs. 1.0% for OLIF.

Use of rhBMP-2 and ≥ four-level LLIF procedures were associated with higher risk of postoperative deficit.

Abdominal wall paresis

Aka "pseudohernia"

Due to iliohypogastric or ilioinguinal nerve injury, usually recovers spontaneously.

Wound infection

Rates - Uribe 2015

Superficial wound infection	35 (0.27 %)
Deep wound infections	18 (0.14 %)

Vascular injury

Rates - Uribe 2015

Vascular complications, n (%)	13 (0.10 %)
Visceral complications, n (%)	11 (0.08 %)

Other interbody fusion comparisons

OLIF vs. ExLIF Approach Comparison:

Transpsoas group had higher rates of transient thigh/groin sensory symptoms and transient hip flexor weakness, and increased prolonged motor deficits.
Prepsoas group had higher rates of sympathetic plexus injury (none in transpsoas) and higher rates of major vascular injury.
Rates of bowel and urological injury were similar.

ExLIF vs ALIF

Smith et al. (J Clin Neuro 2012)

1–2 level XLIF (115 patients): 36 and 43 hour LOS.
1–2 level ALIF (87 patients): 72 and 96 hour LOS.

From lecture

Reported ALIF complications

Visceral: 5% - 13.9%
Vascular: 2.2% - 6.7%, as high as 18%
Reproductive: 9.6% (in males)

Reported XLIF complications

Visceral: <1%
Vascular: <1%
Reproductive: <1%

ExLIF vs PLIF

Length of stay

Lucio et al 2012 (Risk Management and Healthcare Policy 2012)

2-level XLIF (109 patients): 1.2 day LOS.
2-level open PLIF (101 patients): 3.2 day LOS.

Rodgers et al 2010. (Spine 2010 – Fusion in Octogenarians)

XLIF (40 patients): 1.3 day LOS.
Open PLIF (20 patients): 5.3 day LOS.

Neurological deficit

TLIF/PLIF: 3-9.6%
ExLIF: 0.7-2.9%

Outcome

Reoperation rates

XLIF (no additional fixation): Ozgur et al. (SAS J 2010) – 0% reoperation rate; Rodgers et al. (Spine 2010) – 5%.
XLIF with MIS fixation: Isaacs et al. (Spine 2010) – 0% re-operation rate.
XLIF with open fixation: Isaacs et al. (Spine 2010) – 0% re-operation rate.
XLIF (unspecified fixation in title, individual series):

Hyde et al. (WSCJ 2011): 2.6%
Rodgers et al. (Spine 2011): 1.8%
Knight et al. (JSDT 2009): 1.7%
Youssef et al. (Spine 2010): 0%

Images

Video

Evidence

Cheng 2015:

Comparing:

Traditional transpsoas (TP) approach:

Dissection is performed through the psoas using neuromonitored sequential dilation, without direct visualization of the psoas during dilation.

Direct visualization (DV) approach:

Retractors are initially docked superficial to the psoas, and the surgeon then performs a directly visualized dissection through the psoas with identification of the lumbar plexus before placing retractors deep within the psoas.

Overall adverse events

Any postoperative adverse event occurred in 25.8% of patients (31/120), with 36 total events recorded; 1.7% required unplanned return to theatre and there were no deaths.
Neurologic adverse events (thigh dysesthesias, radiculopathy, weakness) occurred in 18.3% overall, and 98.2% of patients were independently ambulant at first postoperative follow‑up.

TP vs DV: neurologic AEs

Considering all levels, neurologic AEs occurred in 24.0% of DV cases versus 14.2% of TP cases (not statistically significant at this sample size).
For single-level fusions, neurologic AEs were significantly higher with DV (28.6%) than TP (10.2%, p ≈ 0.03), suggesting TP with neuromonitoring may better limit plexus-related morbidity in this context.

Most common neurologic complaint was

Anterior/lateral thigh paresthesia (12.5%),
Radiculopathic leg pain (5.0%) and postoperative weakness (2.5%).

Overall AE rates with the lateral approach (≈26%) were comparable to published complication rates for anterior and transforaminal lumbar interbody fusion techniques, indicating that lateral transpsoas fusion has a nontrivial but similar risk profile to established approaches.

Tohmeh 2011:

102 patients undergoing XLIF at L3–4 and/or L4–5 found that dynamic, directionally sensitive, threshold-based EMG (NeuroVision) reliably identifies the lumbar plexus during the transpsoas approach and is associated with a low rate of persistent neural injury
Nerve detection

Alert-level feedback (≤10 mA) indicating nerve proximity occurred in 53.9–55.7% of cases overall, more often at L4–5 than L3–4.

Complications

Intraoperative complications were rare, with 2 minor peritoneal perforations (1.96%) not requiring repair.
Transient approach-related deficits were common but self-limited: 27.5% had new iliopsoas/hip flexion weakness (typically MRC 4/5) and 17.6% had new upper medial thigh sensory loss, both usually resolving within ~2 weeks and attributed to psoas trauma rather than nerve injury.
True new motor neural deficits occurred in 3 patients (2.9%)—one foot dorsiflexion weakness and two quadriceps weaknesses—all resolved by 6 weeks to 6 months; in two of these, non-alert thresholds were present and free-run EMG changes correlated temporally with implant manipulation or difficult revision surgery.

Pros and cons

Pros

Benefits of minimally invasive surgery (MIS)

Less morbidity

less infection
Reduce blood loss

Less pain
Shorter hospital stays
Faster recovery

Avoiding the morbidity of a transperitoneal approach.

Larger surface area for intervertebral graft positioning → higher fusion rate

Alignment advantages

Powerful coronal correction

Modest sagittal correction

ALL release (ACR) allows more correction

Cons

Lumbar plexus injury

Sensory: 36%
Motor: 5% (femoral nerve injury)

Might not achieve adequate sagittal correction

Needs lateral positioning

Takes time

Neuro-monitoring required

Vascular injury

Learning curve

Limited approach can only access L1-L5 (mainly L2/3 and L3/4)

As the most proximal and most distal of those disc spaces may be difficult to enter due to ribs and iliac crest