Lateral lumbar surgery for the treatment of degenerative lumbar scoliosis and stenosis

Decompression and stabilization of the degenerative lumbar spine using a minimally invasive extreme lateral approach: the XLIF experience

Degenerative scoliosis of the lumbar spine is a consequence of the natural deterioration of the intervertebral disks with age.  The biomechanical integrity of the disk declines with age.  Wear and tear on the disc causes oxidative damage to the proteins that make up the core of the disk.  Over time, the joint becomes unstable and the vertebral bodies start to slip out of alignment.  Some patients will develop degenerative disease of the lumbar spine without scoliosis, while others will develop significant scoliotic and kyphotic deformities.  The reason for this is unclear: why do some people get degenerative disease without scoliosis, while some people get severe scoliosis.  I presume that it may have something to do with posture, handedness, and asymmetrical forces acting on the spine over years and years of activities of daily living.

The symptoms of degenerative scoliosis

Patients with degenerative scoliosis of the lumbar spine typically come to clinic with two complaints: (i) back pain and (ii) leg pain.  In conjunction with their leg pain, they often have difficulty walking.  Usually, their walking endurance has declined in recent years.  Many of these patients will report that after walking a short distance they have to stop, sit down, lean forward.  After a few minutes their legs feel refreshed and they are able to get up and walk again.  Declining walking endurance is a symptom of neurogenic claudication.  Claudication is a word that means cramping pain.  In this case, the cramping pain is caused by spinal stenosis squeezing the nerve roots.  The blood supply to the nerve roots in the lumbar spine is decreased by increased disk bulging associated with weight bearing.  Forward flexion of the spine alleviates the pressure and restores the blood flow to the neural elements.  Here are two slides from a famous pathological collection of images that demonstrate the changes that occur — disk bulging and ligamentum flavum hypertrophy — that cause stenosis.  The first picture is from a young male, the second from someone in their 60’s or 70’s.


normal lumbar spineligamentum-flavum-hypertrophy-disk-bulge

Back pain and degenerative scoliosis

The back pain associated with degenerative scoliosis of the spine is a mechanical ache.  Patients typically feel worse at the end of the day or after spending a long time on their feet.  The pain is typically in the midline but tends to radiate around to the hip in a “belt like” distribution, and they often have bilateral deep seated buttock pain.

XRAY and MRI findings in degenerative scoliosis

Here are several plain xrays and the MRI scan of a 60 year old physically active male with degenerative kyphoscoliosis of the lumbar spine and associated spinal stenosis.  The plain xrays are taken in the standing position and they demonstrate that the disks have deteriorated and the vertebral bodies have started to slip out of alignment with respect to each other.  There is an abnormal side to side curvature of the spine.  This is the scoliotic component of degenerative diseass.  The anterior aspect of the lumbar spine has collapsed resulting in a flat or rounded low back.  This is the kyphotic component of degenerative disease.

Nerve root compression caused by degenerative scoliosis

The MRI scan demonstrates that at several levels there is significant compression of the space available for the nerve roots.  The most frequent area of compression is in the lateral recess areas of the spinal canal and in the neuroforamen where the nerve root is particularly vulnerable to compression.  Here several key images and the radiologist’s report of this patient’s pre-operative MRI scan:

pre op para saggital neuroforamenpre op axial L3.4


The Radiologist’s Report

CLINICAL HISTORY: Sciatica pain and weakness with numbness left leg.
COMPARISONS: No previous.
TECHNIQUE: Sagittal T1, sagittal STIR T2, high spatial resolution sagittally acquired 3D T2 SPACE which was also reformatted as axial T2 images, and axial Tl images were acquired on 1.5T Siemens Magnetom.
CONTRAST: Noncontrast exam.


Lower T-spine: Visualized portions of the lower T-spine from T9 to T12 are relatively normal in appearance for age without canal or foraminal stenosis and without any distal cord or conus imprint or compression. Posterior disc protrusions are seen at T6-7, T7-8, T8-9 and T9-10 levels. While these indent the anterior CSF space no frank cord compression is appreciated.

Alignment: Mild focal dextroscoliosis of lumbar spine at L2-L3 levels is present. Degenerative translational spondylolisthesis to the right of L2 and L3 with respect to Ll and L4 is present. In addition L3 shows anterolisthesis with respect to L2 and L4.

Anatomy: Nonnal vertebral anatomy is present in that the last rib bearing vertebral body is presumed to be T12 and 5 lumbar type vertebral bodies are present. The tip of the conus is seen at the T12-L1 level.

Lumbar discs:

T12-L1: Normal for age disc level.

L1-2: Moderate degenerative disc disease is present. Broad posterior disc osteophytic ridging indents the anterior margin of the central CSF space without central canal stenosis and causes mild right foraminal narrowing and moderate left foraminal narrowing but no definite nerve root abutment, displacement or impingement is seen at this level.

L2-3: Severe degenerative disc disease is present especially on the left with obliteration of the disc space and endplate irregularities. Broad posterior osteophytic ridging related to the anterolisthesis of L3, causes mild central canal narrowing but more importantly causes moderately severe left neural foraminal narrowing, moderate left lateral recess encroachment, mild right lateral recess narrowing and mild/moderate right neural foraminal narrowing. There may be some nerve root abutment within the lateral recesses but no definite nerve root impingement is seen at this level.

L3-4: Severe degenerative disc disease is present due to Grade I, borderline Grade II anterolisthesis of L3. Osteophytic ridging in conjunction with facet arthrosis and hypertrophy results in moderate central canal stenosis with central nerve root abutment. More importantly there is severe bilateral neural foraminal narrowing with nerve root impingement suggested in both neural foramina.

L4-5: Mild degenerative disc disease with 3-4 nun broad posterior disc protrusion centrally. This effaces the anterior epidural fat and minimally indents the anterior margin ofthe central CSF space without significant central canal stenosis. There is mild bilateral lateral recess encroachment with nerve root abutment but no definite displacement or impingement. Neural foramina are moderately narrowed on the left and moderately severely narrowed on the right with some nerve root abutment within the foramina but no definite impingement.

L5-S1: Moderate to moderately severe degenerative disc disease is present with large right anterior and far right lateral osteophytic ridging. Broad posterior disc osteophytic ridging effaces the epidural fat but no central canal stenosis is seen. Broad posterior disc osteophytic ridging does abut descending nerve roots within the lateral recesses bilaterally. The right neural foramen is severely narrowed with nerve root abutment if not imprint. The left neural foramen is more patent without evidence of nerve root abutment.

Facet Joints: Facet joints demonstrate asymmetical arthrosis at L1-2 and L2-3. Facet arthrosis is relatively severe on the right at L3-4. Mild arthrosis right worse than left is seen at L4-5 and L5-S1.

Paraspinous spaces and soft tissues: Within normal limits. STIR images show disc dehydration L1 to S1 levels and there is marrow edema surrounding the severe degenerative disc disease changes at L3-4 consistent with active ongoing degenerative disc disease superimposed on chronic degenerative disc changes .

1. Grade I to borderline Grade II anterolisthesis of L3 with respect to L2 and L4 with severe degenerative disc disease at L2-3 and L3-4levels and severe foraminal narrowing at L3-4 with apparent nerve root impingement.  Serpiginous nerve roots within the lumbar levels are secondary evidence of nerve root impingement.
2. Relatively severe anterior and far right lateral osteophytic ridging at L5-S 1 as well as broad posterior disc osteophytic ridging L5-S1 that abuts nerve roots within the lateral recesses and appears to cause some imprint of the nerve root within the right neural foramen at L5-S1.

Interpreting the MRI report

These are the images from the MRI scan that demonstrate spinal stenosis.  The axial images are often the most helpful, and I explain to patients that the normal spinal canal should look a little bit like the Texas Longhorn’s logo.  You should be able to clearly trace the path of the neuroforamen along the length of the longhorn.  In stenosis, the area at the base of the horn become obliterated by arthritis from the facet joint and disk space bulging.

The extreme lateral approach for degenerative scoliosis

Approximately 10 years ago, a very innovative surgeon in Sao Paulo, Brazil, developed a novel technique for decompressing and stabilizing degenerative disease of the lumbar spine.  He recognized that there is a surgical corridor to the spine through the side of the patient’s trunk — called the extreme lateral approach.  This approach has many advantages over the standard posterior midline approach to the spine, and one or two distinct disadvantages.  Via the extreme lateral approach, the intervertebral disks of the lumbar spine can accessed, and with the use of specially designed devices, the height of the disk spaces can be restored to their pre-degenerative height and alignment.  A company in San Diego, California, known as NuVasive has been instrumental in developing the specialized tools and implants used during this surgery.

The advantages of the XLIF approach

The advantages of the extreme lateral approach include the fact that the surgical approach (i) does not disrupt the large muscles of the back (ii) is possible with minimal blood loss (iii) allows for the insertion of intervertebral spacers that rest on a strong part of the bone called the apophyseal ring that provides an excellent platform for restoration of disk height and alignment.  The disadvantages of this approach are related to the fact that intervertebral spacers must be carefully inserted through the psoas muscle without damaging a complex of nerves called the lumbar plexus.  The psoas muscle is the major muscle that flexes the hip joint.  There are techniques and special surgical tools available that make it possible to dilate surgical channels through the substance of the posas muscle with minimal bleeding, but some degree of posas irritation with thigh pain, numbness, and weakness in hip flexion is expected after the surgical approach.  These symptoms seem to be transient and most patients report that their strength returns rapidly and any pain or weakness is minimal within a few weeks of surgery.

The lumbar plexus can get in the way

The lumbar plexus is a dense collection of nerves that run through the substance of the psoas muscle.  Nerve fibers do not tolerate much surgical manipulation so the key to this procedure is knowing where the nerves are so that they can be avoided.  Nuvasive has pioneered a very innovative tool called Neurovision that makes it possible to stimulate the nerves with a tiny ball tip electrode so that the course of the nerves in the posas muscle can be visualized without being seen and therefore avoided.  The operation is technically challenging but has great potential to treat this problem with limited tissue disruption.

Surgery in this case for degenerative scoliosis

This patient was operated upon in the lateral position.  Lying on his side, a 2 inch incision between the ribs and pelvis was made, and with careful surgical dissection, working channels were established in line with three degenerative disks — L1/2, L2/3, and L3/4.  Prior to surgery these disks had basically completely collapsed, but during the course of surgery, 10mm high spacers made out of a biopolymer called polyetheretherketone (PEEK) were inserted into the degenerative disk spaces.  This process restores disk height, restores spinal alignment, and increases the amount of space for the nerve roots in the spinal canal.  On post-operative day #1, after a 1 night stay in the hospital, standing X-rays were taken of the spine and we also obtained a post-operative MRI scan.  These images demonstrate the improvement in spinal alignment, disk height, spinal canal and neuroforaminal volume.  In fact, the radiologist was kind enough to measure the the amount of improvement in the dimensions of the spinal canal.


preop lateral MRI lumbarpost op lateral lumbar MRI sagittalpre-op-axial-L3.4-with-localizerL34-minimal-stenosis

The radiologists report after the operation


L1-L2:  Ligamentum flavum hypertrophy with degenerative facet change.  Mild narrowing of the left neural foramina.  The central canal measures 15 mm. There has been interval improvement in the degree of neural foraminal narrowing on the left.  The central canal is stable at this level.

L2-L3:  Ligamentum flavum hypertrophy and degenerative facet change.  There is moderate osseous narrowing of the bilateral neural foramina, the degree of neural foraminal narrowing improved when compared to the prior study.  The central canal measures 17 mm, this is also improved from 10 mm.

L3-L4:  Ligamentum flavum hypertrophy and degenerative facet change with moderate narrowing of both neural foramina.  The central canal measures 14mm.  There has been improvement in the degree of neural foraminal and central canal narrowing when compared to the prior study, with the central canal previously measuring 8 mm.

L4-L5:  Ligamentum flavum hypertrophy and degenerative facet change with a broad-based disc bulge.  There is moderate narrowing of the right greater than left neural foramina.  The overall appearance is stable.  The central canal is widely patent, measuring 12 mm.

This can be a minimally invasive operation

This surgical procedure for decompressing and stabilizing the lumbar spine is possible with relatively minimal blood loss, a short 1 or 2 day hospital stay, and a relatively quick recovery.  In published reports, the fusion rate is very favorable and in carefully selected patients it appears that it is possible to accomplish the goals of surgery — increasing space available for the nerve roots and realigning the spine — without resorting to supplemental posterior fixation using traditional pedicle screws.

degenerative-kyphoscoliosisAP-lumbar-post-oppreop lateral MRI lumbarpost op lateral lumbar MRI sagittal

After posting this link, the next patient that I treated in a similar fashion read this as part of his pre-operative preparation and his main question was as follows:

Dear Dr. Gollogly, I have read the material here and on your web page and have found it informative.

I have one question: What should I expect when I return home from the operation and hospital stay? Do I need to make any special accommodations at for sleeping, sitting, etc? You said I would be wearing a back brace of some sort. How will that limit my movement?

My response follows: After your operation you should not need to make any special accomodations for sleeping or sitting.  We will fit you in a lumbar brace that you fasten around your waist with velcro.  It looks like the sort of brace that you see the stockers at the supermarket wearing.  It supports your spine and prevents a little bit of movement, but it is not too restrictive.  It’s a soft brace, not a hard plastic shell.  You should try to avoid any kind of heavy lifting and sustained flexion (being bent over) of the lumbar spine for the first 6 weeks after surgery.  The brace helps to remind you to sit up straight, walk with good posture, and rather than bending over to pick things up off the ground, use your legs.

XLIF Youssef


Back pain in athletes

Low back pain in athletes

One of the more frequent reasons that a younger athletic patient, meaning anyone from the age of about 15 to 25, comes to see me in consultation is because they have severe activity related back pain that hasn’t responded to the usual treatments of rest, a couple of weeks of reduced activity, and over the counter anti-inflammatory pills. It’s a really challenging situation because in almost every case, the athlete can rest, rehabilitate, and get back to about 80% of their peak performance, but once they try to push it to become game ready, their pain returns.


Here’s a couple of actual examples of patient histories:

a 16 year old nationally ranked tennis player with plans to play Division 1 college tennis has been plagued by left sided back pain for the last 6 months. The pain is directly related to the number of overhead serves that he makes and to the number of sets that he plays. He has no pain at rest, no pain while cross-training, and no pain while playing at less than 80% of his full speed, hard hitting game. However, once he steps it up to match level play, after a few sets his back starts to seize up and he has had to withdraw from several tournaments.

a 17 year old competitive cross-country runner was cross training under the supervision of a strength and conditioning coach when she felt a sharp “pop” in her back while squatting with moderately heavy weights. Ever since, she has severe pain when sprinting, stair-climbing, or performing weighted lunges. The rest of the time she is basically normal. The injury happened over a year ago and in spite of rest, chiropractic massage, ice, and anti-inflammatories, she can’t sprint without her back seizing up.

I see similar histories up to about 25 years of age, so if this sounds familiar, keep reading.

Most of these patients have had plain X-rays of their spines before their visit, and many of them have had an MRI as well. Typically, these studies will demonstrate one of the following three conditions, in order of increasing severity:

1. a “stress reaction” in the pedicle of L5
2. spondylolysis or a “pars defect” of L5


3. spondylolisthesis at L5/S1

These findings are pretty common. For example, in a study of 19 competitive gymnasts attending a training camp that were selected basically at random and had MRI scans of their spine, spondylolysis was found in 3 of the 19 athletes, spondylolisthesis in 3 as well, and focal bone-marrow edema was found in both L3 pedicles in one gymnast. Since most of the patients are accomplished athletes to begin with, the usual prescription for six to eight weeks of physical therapy is rarely of much benefit. Most of the time they have already seen one or two trainers, conditioning coaches, or chiropractor-type practicioners before they come and see me, and they are usually pretty frustrated. Here are a couple of sample X-rays and MRI scans showing the findings that accompany them on their first visit.

These two slices of an MRI scan demonstrate a “stress reaction” in the pedicle of the vertebral body. The stress reaction shows up as white area in a part of the bone that normally has a darker appearance on MRI. This particular sequence of the MRI scan is formatted so that water shows up as a bright white signal and the presence of increased water content in this area is said to represent bony “edema”.
stress reaction in the pediclebilateral L5 bony edemaMRI pars defectL5 pedicle edema
Edema is defined as “a condition characterized by an excess of watery fluid collecting in the cavities or tissues of the body”, and we see edema in the bone underneath the cartilage of arthritic joints, surrounding fractures, and in bone that has been bruised by hard impacts. Here are a couple of examples of bony edema.

The presence of bony edema is definitely a pathologic finding. Something is wrong with the musculoskeletal system in the immediate area and the bone is not happy. In this case, this MRI scan belonged to a 16 year old male football player who was working out with a conditioning coach who was having him squat very deeply with pretty heavy weight — on the order of 1.5 times his body weight — and his pain seemed to be due to hyperextension of the spine at the bottom of the squat.

Here is an example of a spondylolysis or a “pars defect” of L5. In this case there is a physical break in bone across the pars inter-articularis. The break is usually described by the radiologist as a defect, a lysis, or a stress fracture. All of these terms are synonymous, and they all indicate that there is a physical gap in the bone. Occasionally I will get a patient who comes to the office in a bit of a panic after being told that he or she has a “fractured spine”, but this is probably a bit too strong of a phrase to describe this finding accurately. The classic X-ray finding of a spondylolysis is known as the “scotty dog” sign. This sign describes the manner in which the spondylolysis defect can look (to someone with a very healthy imagination) like the collar on a scotty dog on the oblique views of the limbo-sacral junction. While the gap can be seen on plain X-ray, often a CT or an MRI scan is needed to really confirm that it is there, because the X-ray can be a little bit unclear. The reason why the use of the word “fracture” is not terribly appropriate here is because this is typically not an acute break, the gap in the bone is often filled with fibrous tissue, and there is usually some degree of residual stability to the vertebral body. Sometimes there is edema surrounding the defect, and sometimes not. Typically, patients with more severe back pain tend to have relatively more edema, but this is not a perfect relationship.

lateral xray spondylolysisspondylolysis-obliquepars-interarticularisscotty-dog-parsspondylolysis-scotty-dogathletic-back-pain

Finally, here is a case of spondylolisthesis at L5/S1. In this case the to halves of the vertebral body have started to move apart and the spondylolysis defect is noticeably larger. The overall alignment of L5 with respect to S1 has shifted, and L5 has slipped anteriorly with respect to S1. This finding is more common in females who tend to have more supple ligaments and presumably more flexible intervertebral disks, and it is more common in patients with more vertically oriented L5/S1 disk spaces, presumably because there are greater forces acting to displace L5 on S1 in patients with more lumbar lordosis and vertically oriented sacral endplates.

Let’s imagine that all three of these patients have pain only with strenuous athletic activity. Why? My opinion is that area where the stress reaction, pars defect, or spondylolisthesis occurs is placed under some sort of tension or stress ONLY when the spine is moved to the limits of its range of motion under the heavy loads of torque, muscular contraction, and athletic movement. For example, it’s not hard to imagine why the lumbar spine would be stressed during the twisting, lunging, and hitting motions of these competitive tennis players in ways that are fundamentally different than the stress imposed by the more mundane activities of daily life.



Will it heal? This seems to be the most frequent first-asked question once the diagnosis has been made, and the important thing that needs to be clarified what you meant by “healed”: less pain or a normal X-ray or MRI scan? When it comes to the actual findings on the X-rays or the MRI scan it’s hard to know for sure, but my opinion is that the stress reaction will probably subside and will not necessarily progress to a spondylolysis if the activity responsible for the pain is not a repetitive motion that the athlete plans to continue to perform. I think that once a spondylolysis has occurred, it is usually going to be a persistent defect and if there is any evidence of anterior displacement in the form of a spondylolisthesis bone certainly won’t bridge the gap or restore the alignment back to normal.

Should I use a bone stimulator? Unclear. Most patient’s will improve with some form of conservative treatment, so the gold standard supporting the use of a bone stimulator would be radiographic evidence of healing of the spondylolysis defect after treatment. As of 2013, there are no studies that have not been any published studies that have conclusively demonstrated that a bone stimulator results in radiographic healing in a large series of patients. In my practice, I leave the decision up to the athlete and the parents and to be perfectly frank, it usually comes down to a question of insurance coverage. If the family has good insurance and they are not terribly bothered about the cost, I have no problem recommending and prescribing a bone stimulator. However, it’s not something that I would push, especially if it was going to cause any financial hardship.

What about rehab? This is the most interesting part of the entire problem and the question that I think the most about. Here’s a short video on a competitive cross-fit athlete that successfully rehabilitated herself back to a very high level of functional movement after having an episode of back pain that appears to be due to a spondylolysis or spondylolisthesis.


I’ve been a big fan of Kelly Starrett for a number of years — mostly as a result of my own Crossfit experiences as a 40 year old + athlete, and I think he does an excellent job of explaining the body mechanics of a “stable” and “organized” spine and how this type of posture can reduce the stress and strains on the lumbar spine during functional movements. I’ve had a lot of good results with patients when I refer them to particular physical therapists who are skilled in coaching olympic weightlifters and who have a solid understanding of the protective effects of good posture and core strength and endurance. This is where I personally try to put most of my emphasis, but it’s hard to unlearn habits that work. For instance, in the case of the competitive tennis player who was case #1, his serve worked for him. He was able to achieve killer spin and power with dramatic hyperextension of his lumbar spine, and while his pars paid the price, so did his opponent. Unlearning that serve seems unlikely, but with a combination of cross training, postural education, and attempts to change his style of hitting, he has managed to reduce his pain to the point where he can play with a tolerable level of discomfort.

My advice is: spend the money on good coaching. The coast of california seems to have more Crossfit gyms than 7-11’s these days, and the increasing popularity of olympic weightlifting — with it’s attendant risks and benefits — has lead to a dramatic increase in the number of people in the local athletic community who really are knowledgeable about the ways to protect and stabilize the spine during functional movements under the loads imposed by athletics.

1. Skeletal Radiol. 2006 Jul;35(7):503-9. Epub 2006 Mar 7.
Lumbar spine MRI in the elite-level female gymnast with low back pain.
Bennett DL, Nassar L, DeLano MC.
University of Iowa, Roy J. and Lucille A. Carver College of Medicine, Department of Radiology, 200 Hawkins Drive, Iowa City, IA 52242, USA.
Previous studies have shown increased degenerative disk changes and spine injuries in the competitive female gymnast. However, it has also been shown that many of these findings are found in asymptomatic athletic people of the same age. Previous magnetic resonance imaging (MRI) studies evaluating the gymnastic spine have not made a distinction between symptomatic and asymptomatic athletes. Our hypothesis is that MRI will demonstrate the same types of abnormalities in both the symptomatic and asymptomatic gymnasts.
Olympic-level female gymnasts received prospectively an MRI exam of the lumbar spine. Each of the gymnasts underwent a physical exam by a sports medicine physician just prior to the MRI for documentation of low back pain. Each MRI exam was evaluated for anterior apophyseal ring avulsion injury, compression deformity of the vertebral body, spondylolysis, spondylolisthesis, degenerative disease, focal disk protrusion/extrusion, muscle strain, epidural mass, and bone-marrow edema.
Nineteen Olympic-level female gymnasts (age 12-20 years) were evaluated prospectively in this study. All of these gymnasts were evaluated while attending a specific training camp.
Anterior ring apophyseal injuries (9/19) and degenerative disk disease (12/19) were common. Spondylolysis (3/19) and spondylolisthesis (3/19) were found. Focal bone-marrow edema was found in both L3 pedicles in one gymnast. History and physical exam revealed four gymnasts with current low back pain at the time of imaging. There were findings confined to those athletes with current low back pain: spondylolisthesis, spondylolysis, bilateral pedicle bone-marrow edema, and muscle strain.
Our initial hypothesis was not confirmed, in that there were findings that were confined to the symptomatic group of elite-level female gymnasts.


Sohrab Gollogly, MD is a board-certified orthopedic surgeon and Fellowship-trained spine surgeon who also performs scientific research and participates in several volunteer surgical organizations.

Dr. Gollogly completed his undergraduate education in biology at Reed College in Portland, Ore. He earned his medical degree from the University of Washington School of Medicine.

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