Curve/Countercurve

TLIF, XLIF or ALIF for Adjacent Segment Degenerative Disc Disease

Nitin N. Bhatia, MD, Stephen Timon, MD, Eric S. Wieser, MD, Jeffrey C. Wang, MD

Case Presentation
A 50-year-old man presents to the spine clinic with a chief complaint of chronic worsening low back pain (LBP) for over five years. He has a history of an L4-S1 decompression and in situ posterolateral fusion approximately 25 years ago. His complaints are of 90% LBP versus 10% lower extremity symptoms of which most are buttock and thigh pain consistent with discogenic pain.

His physical exam is positive for restricted range of motion of the lumbar spine with increased pain with extremes of motion. He has a well healed midline lumbar incision and is neurologically intact. Sciatic tension signs are negative. (X-rays and MRIs are shown on next page.)

He has undergone extensive medical and interventional treatment modalities including physiotherapy, NSAIDS, epidural steroid injections, chiropractic treatments and acupuncture without success. He can no longer work  secondary to his pain and presents to the spine clinic after extensive conservative treatment to discuss surgical
options. What would you recommend?

Nitin Bhatia, MD, Responds
This patient exemplifies a fairly common and challenging scenario facing spine surgeons today. To address this patient, we need to answer several fundamental questions. First, the patient’s primary complaint must be correctly correlated with anatomic pathology. Then decide whether the patient’s problem can be reliably improved with surgical intervention. Finally, evaluate the available surgical options in order to optimize outcomes and minimize iatrogenic morbidity.

In this case, a 50-year-old man with a history of an L4-S1 decompression and in situ fusion now has severe adjacent segment degenerative disc disease at L3-4 and resultant axial back pain. Radiculopathy is not a major complaint for this patient. The imaging studies show isolated disease confirmed with MRI scans and no significant canal stenosis. Discography is likely not necessary in the work-up of patients with severe, one-level degenerative changes and axial back pain, and the results of discography are controversial at best.1 Assuming that the patient has failed extensive nonsurgical treatment and has no significant psychological or medical confounding factors, surgery may be considered. The patient should be counseled that the results of surgery for axial back pain are varied and that surgery is performed as a last resort only.

Once a surgically treatable problem has been identified, approaches are considered. This patient has several options. Because of his previous posterior decompression and in situ fusion, he is not an optimal candidate for lumbar disc replacement. First, select isolated posterolateral fusion versus posterolateral and interbody fusion. Although some studies have suggested that posterolateral fusion may have similar results to interbody fusion for axial
back pain,2 others have shown that interbody fusions better stabilize the anterior column and may have better outcomes than posterolateral fusion alone.3 In order to more completely remove the degenerated disc and reconstruct the anterior spinal column, I prefer to perform an interbody fusion for patients with degenerative disc disease (DDD) and axial back pain.

There are three basic approaches for performing an L3-4 lumbar interbody fusion: anterior (ALIF), extreme lateral (XLIF), or via a posterior approach (in this discussion, transforaminal [TLIF]). Each of these procedures has distinct advantages and disadvantages. With ALIF, the incidence of retrograde ejaculation in men may be as high as 5%4 which needs to be clearly discussed with patients pre-operatively. This rate, however, is likely significantly lower at the L3-4 level than the L5-S1 level due to the distance from the superior hypogastric plexus. Recent development of anterior lumbar tension band plates has provided the technology to improve the stability achieved from an anterior-only approach. This stability, however, does not equal that achieved with pedicle screw fixation.5 Anterior revision of ALIFs can have high rates of complications because of postoperative scarring, with vascular complication rates of
over 50% in some studies.6

Definite risks are also associated with TLIF. Nerve root retraction is frequently necessary when placing the interbody device and postoperative neuropraxia or epidural fibrosis can develop. Additionally, complete posterior disc space preparation is challenging. Wide disc space and end plate preparation are mandatory to achieve high interbody fusion rates. Unilateral disc space preparation via a TLIF approach may only adequately prepare 56% of the end plate surface area.7 Local, anatomic constraints, including the exiting nerve root, limit the TLIF cage size. The smaller cage limits restoration of disc height and sagittal alignment. Dissection and retraction of the posterior spinal musculature may also lead to imparied postoperative muscle function with associated inferior clinical results.8

In this case, the patient’s primary complaint is axial back pain which is likely secondary to his DDD. There is no complaint of radiculopathy nor is there significant stenosis on the imaging studies, and hence canal decompression is not necessary. An ideal procedure for this patient would allow easy access to the intervertebral disc space and placement of a large interbody graft while avoiding the negative aspects of both ALIF and TLIF. XLIF is such a procedure.

XLIF allows excellent disc space preparation, disc space height and alignment restoration without the short- and longterm morbidity of an anterior approach. XLIF requires only minimal retroperitoneal dissection, thus inducing less scarring than with an anterior approach. Additionally, the great vessels anteriorly do not have to be mobilized or protected, thereby reducing the postoperative scarring of these structures. Large interbody devices can be safely placed with no nerve root retraction. Sagittal alignment and disc height may be better restored with XLIF. Furthermore, this patient has previously undergone a posterior decompression and fusion and an XLIF allows us to avoid the surgical site scarring which would likely be encountered through a posterior-only approach.

Beside avoiding the difficulties of the anterior and posterior approaches, XLIF appears to be safe9 and have good clinical outcomes. The XLIF procedure can be combined with lateral plate fixation via the same approach or minimally invasive posterior fixation including pedicle screws, facet screws or spinous process plating. These combinations provide excellent stability with minimal paraspinal muscle dissection and less resultant dysfunction. Unlike the anterior tension band plates used with ALIF, anterolateral instrumentation has been shown to restore spinal stability to intact levels in multiple planes when performed with interbody fusions.10 Certain studies, however, suggest
that pedicle screw instrumentation may provide a higher level of rigidity than anterolateral instrumentation, although this difference is likely not clinically significant in a patient with discogenic low back pain without gross instability.

XLIF is an excellent option in this case but does have some drawbacks. The XLIF approach requires blunt dissection
through the psoas muscle and the traversing lumbar plexus. The use of appropriate nerve root stimulation and monitoring is required to safely approach the disc space. Occasionally, the disc space cannot be accessed using an XLIF technique and a back-up procedure should be available and discussed with the patient preoperatively. Furthermore, a traction neuropraxia can occur because of pressure on the lumbar plexus by the expandable cannulas used to perform an XLIF. These patients may complain of postoperative numbness in the thigh or groin because of injury to the genitofemoral nerve. In one study, 30% of patients developed postoperative numbness, and in two-thirds
of these patients the numbness lasted longer than one month.11 XLIF can be extremely difficult to perform in the low lumbar spine, especially at L5-S1. The L3-4 level, however, can be reliably approached. Because the extreme lateral lumbar approach is relatively new, long-term data about XLIF is not currently available and the published data is sparse at best.

In summary, this 50-year-old man is suffering from axial back pain secondary to his L3-4 adjacent segment degenerative disc disease. XLIF provides a less invasive way to reconstruct the diseased level with minimal side effects and excellent outcomes.

References
1. Carragee EJ, Lincoln T, Parmar VS, Alamin T. A gold standard evaluation of the “discogenic pain” diagnosis as determined by provocative discography. Spine. 2006;31(18):2115-2123.

2. Fritzell P, Hagg O, Wessberg P, Nordwall A, Swedish Lumbar Spine Study Group. Chronic low back pain and fusion: a comparison of three surgical techniques: a prospective multicenter randomized study from the Swedish lumbar spine study group. Spine. 2002;27:1131-1141.

3. Madan SS, Harley JM, Boeree NR. Circumferential and posterolateral fusion for lumbar disc disease. Clin Orthop Relat Res. 2003;409:114-123.

4. Tiusanen H, Seitsalo S, Osterman K, Soini J. Retrograde ejaculation after anterior interbody fusion. Eur Spine J. 1995;4:339-342.

5. Beaubien BP, Derincek A, Lew WD, Wood KB. In vitro, biomechanical comparison of an anterior lumbar interbody fusion with an anteriorly placed, low-profile lumbar plate and posteriorly placed pedicle screws or translaminar screws. Spine. 2005;30:1846-1851.

6. Nguyen HV, Akbarnia BA, van Dam BE, et al. Anterior exposure of the spine for removal of lumbar interbody devices and implants. Spine. 2006;31:2449-2453.

7. Javernick MA, Kuklo TR, Polly DW. Transforaminal lumbar interbody fusion: unilateral versus bilateral disk removal - an in vivo study. Am J Orthop. 2003;32:344-348.

8. Rantanen J, Hurme M, Falck B, et al. The lumbar multifidus muscle five years after surgery for a lumbar intervertebral disc herniation. Spine. 1993;18:568-574.

9. Ozgur B, Aryan H, Pimenta L, Taylor W. Extreme lateral interbody fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion. Spine J. 2006;6:435-443.

10. An HS, Lim TH, You JW, Hong JH, Eck J, McGrady L. Biomechanical evaluation of anterior thoracolumbar spinal instrumentation. Spine. 1995;10:1979-1983.

11. Bergey DL, Villavicencio AT, Goldstein T, Regan JJ. Endoscopic lateral transpsoas approach to the lumbar spine. Spine. 2004;29:1681-1688.

Stephen Timon, MD, Responds
Adjacent level disease has become common diagnosis facing adult spine surgeons. With the advent of pedicle screws, lumbar plates and stand-alone devices, the number of lumber fusions has increased. Subsequently, the number of complications has increased, especially adjacent level degeneration. Although many more patients have achieved solid fusion becasue of these advances, more adjacent levels are stressed due to the higher number of fusions performed.

This 50-year-old man with a history of a prior L4-S1 decompression and in situ fusion had an excellent outcome for the past 20 years. Now he has axial back pain without radiculopathy. He has failed nonoperative management including weight loss, physical therapy and pain management. The patient was given the option of either continued nonoperative management or surgical treatment. A comprehensive physical and radiologic evaluation was performed. Radiographs reveal prior decompression and fusion at L4-S1 posteriorly, with significant disc height maintained anteriorly at L4-S1. Severe degeneration of the L3-4 disc space is noted by disc space collapse and subchondral sclerosis. The flexion and extension films show no evidence of instability. Magnetic resonance imaging reveals modic end plate changes in the L3 and L4 vertebral bodies and no evidence of neural compression.

Now that the patient has been counseled about his condition and he wishes to proceed with surgery, many options are available to him. These include posterior fusion alone (in situ and with instrumentation), posterior fusion with interbody grafting (TLIF), ALIF and XLIF. All three of these procedures have merits and drawbacks; I feel that treating this patient with an anterior alone approach with an interbody graft and anterior plate would greatly benefit the patient. This portion will discuss the potential advantages and disadvantages of ALIF.

In the absence of radiculopathy, a direct decompression is not warranted. Additionally, the patient has multiple levels
of degenerative discs. Presumably L3-4 is the main generator. However, stress continues at both the L4-5 and L5-S1 disc spaces (despite a solid posterior fusion) which could further degenerate causing pain. Discography would be helpful in confirming the pain generator(s).1-2 If the discogram is positive and concordant at only L3-4, then your initial surgical plan is unchanged. But if there is concordant pain in the lower lumbar segments, then these two discs can also be addressed at the time of surgery.

Anterior fusion surgery offers many benefits. ALIF allows the surgeon to prepare a large area for fusion. The majority of the disc is resected along with the anterior longitudinal ligament. After the cartilaginous end plate is removed, a large surface is available to the surgeon for graft optimization. Interbody implants maintain increased motion segment lordosis in order to restore sagittal balance. This restoration of the disc height and lordosis will indirectly decompress the foramina. When compared with TLIF there is a larger area of potential fusion, an increase in the size of the graft utilized and the ability to restore lordosis and aid in the overall sagittal contour of the spine.3-4

Other advantages of the anterior approach to the lumbar spine are: it avoids stripping of the posterior muscles and denervation, and reduces the chance of injury of scarring because direct neural retraction is not involved. Although recent studies have shown some posterior muscular atrophy in anterior-only surgeries, no direct denervation occurs. Additionally, data have been reported that show decreased incidence of adjacent level degeneration in ALIF patients compared to posterior lumbar interbody fusions.5

Although there are many advantages to ALIF, there are many drawbacks as well. Dissection anteriorly involves retraction of the iliac artery and vein. Either of these structures can be injured, resulting in a significant loss of blood.6 Recent studies have shown a higher incidence of vascular injury in cases that required the exposure of L4-5, though the rate of major injuries remains low.7 Injuries to the bowel and ureter, although uncommon, do happen. Retrograde ejaculation is a major potential complication of anterior exposures caused by injury to the sympathetic plexus. Many spinal surgeons will not perform stand-alone ALIFs in males during their reproductive years. Incidences have been reported in the neighborhood of 5%.8 Significantly higher rates of retrograde ejaculation have been reported in  patients undergoing a transperitoneal approach to L4-5 and L5-S1 than a retroperitoneal approach. 9 These aforementioned complications must be discussed at length with potential patients.

Traditionally, ALIFs were performed stand-alone. Early stand-alone ALIFs demonstrated high pseudarthrosis rates.10 Anterior plating for anterior lumbar surgery has increased in popularity and fusion rates have also increased. These fusion rates approach those of circumferential fusion.11-12

ALIF has been utilized by spine surgeons for more than 50 years. While traditional stand-alone ALIF with autogenous iliac crest bone grafts have had high pseudarthrosis rates, new technologies including the use of bone morphogenetic protein (rhBMP), anterior plating and graft optimization have produced significantly higher fusion rates. I feel that these significant advances make this procedure an excellent choice for this particular patient. It allows the surgeon to minimize direct muscular trauma, address the pathology seen and reinforce the prior posterior fusion.

References
1. Carragee EJ, Alamin T. Discogaphy: a review. Spine J. 2001:1:364-372.

2. Anderson MW. Lumbar discography: an update. Semin Roentgenol. 2004;39:52-67.

3. Motosuneya T, Asazuma T, Tsuji T, et al. Postoperative change of the cross-sectional area of back musculature after 5 surgical procedures as assessed by magnetic resonance imaging. J Spinal Disord Tech. 2006 Jul;19(5):318-322.

4. Rantanen J, Hurme M, Falck B, et al. The lumbar multifidus muscle five years after surgery for a lumbar intervertebral disc herniation. Spine. 1993;18:568-574.

5. Min JH, Jang JS, Lee SH, Comparison of anterior- and posteriorapproach instrumented lumbar interbody fusion for spondylolisthesis. J Neurosurg Spine. 2007 Jul;7(1):21-6

6. Fantini GA, Pappou IP, Girardi FP, Sandhu HS, Cammisa FP. Major vascular injury during anterior lumbar spinal surgery: incidence, risk factors and management. Spine. 2007;32(24):2751-2758.

7. Hamdan AD, Malek JY, Schermerhorn ML et al, Vascular injury during anterior exposure of the spine. J Vasc Surg. 2008 Jun 26. [Epub ahead of print]

8. Tiusanen H, Seitsalo S, Osterman K, Soini J. Retrograde ejaculation after anterior interbody fusion. Eur Spine J. 1995;4:339-342.

9. Sasso RC, Burkus KJ, LeHuec JC. Retrograde ejaculation after anterior lumbar interbody fusion:transperitoneal versus retroperitoneal exposure. Spine 2003 May 15;28(10):1023-6

10. Kumar A, Kozak JA, Doherty BJ, Dickson JH. Interspace distraction and graft subsidence after anterio lumbar fusion with femoral strut allograft. Spine. 1993;18(16):2393-2400.

11. Aryan HE, Lu DC, et al. Stand-alone anterior lumbar discectomy and fusion with plate: initial experience. Surg Neurol. 2007;68(1):7-13; discussion 13.

12. Burkus JK, Dorchak JD, Sanders DL. Radiographic assessment of interbody fusion using recombinant human bone morphogenic protein type 2. Spine. 2003;28(4):372-377.

Eric Wieser, MD, Responds
This 50-year-old gentlemen presents with a relatively common complaint of low back pain (LBP) many years after a lumbar fusion. Many factors have led to this situation including the natural history of lumbar spondylosis, but we cannot ignore the fact that the biomechanics of the lumbar spine have been drastically changed after a multilevel-fusion to the sacrum. As we tackle this and other challenging patients,consider each option as it relates to our individual surgical experience and the patient’s individual pathology.

In this case, a 50-year-old man who underwent an L4-S1 decompression and in situ posterolateral fusion 25 years ago, has developed severe adjacent segment degeneration at L3-4 resulting in severe axial, discogenic LBP without radiculopathy. The imaging studies do not suggest central canal stenosis. On the sagittal MRI, the foraminal height should be examined to exclude significant “up-down” foraminal stenosis. Vertebral end plate changes at L3-4 suggest severe degeneration of the disc at that level. Vertebral end plate changes are bone marrow lesions visible on MRI and are assumed to be associated with advanced degenerative intervertebral disc disease. Associations of these end plate or “modic” changes with clinical symptoms are controversial, but recent studies have correlated these changes with both LBP and sciatica with a high positive predictive value.1

A complete work-up of the patient is imperative prior to considering any surgical intervention. In this particular case, I
obtain a CT myelogram to define the bony landmarks, laminectomy defects, and extent of the previous in situ fusion. This can also better demonstrate any possible previous laminotomy at the L3-4 level not obvious on the MRI to allow better preoperative planning on surgical approach. Discography, although controversial, may be considered. However, I do not feel that it is necessary in this circumstance with one-level severe degenerative changes. Assuming that no medical or psychological issues would prohibit a good surgical outcome, he would be a candidate for surgical intervention.

After determining the patient appropriate for surgical intervention, we must decide on the appropriate technique. His
previous lumbar decompression and fusion provides a relative contraindication for lumbar disc arthroplasty. Studies have demonstrated improved outcomes in patients with degenerative changes and chronic LBP treated with fusion versus nonsurgical techniques.2 We must first decide on posterolateral fusion alone versus interbody fusion with or without additional posterolateral fusion. Interbody fusion when addressing disc pathology provides an excellent means of complete removal of the disc with reconstruction of the anterior column via posterior, lateral or anterior approaches to the disc. When approaching severe degenerative disc disease and associated discogenic pain, interbody fusion provides several benefits to posterolateral fusion alone including: complete removal of the diseased disc mechanically and biochemically, ability to restore anterior column support, significant increased fusion surface area thus resulting in higher fusion rates, improved lumbar lordosis, indirect foraminal decompression with restored disc height.

The best approach for this patient is a posterior approach alone via a TLIF with concomitant posterolateral fusion and
pedicle screw instrumentation. The posterior approach to lumbar pathology is the most utilized approach to the lumbar spine and thus familiar to most spinal surgeons. Also, a TLIF approach allows the surgeon to accomplish all goals of surgery including both decompression and fusion through a single approach thus decreasing operative time and logistical issues such as coordinating with an exposure surgeon. This particular case does not require a central decompression but if central decompression was necessary, then it could be achieved directly through this approach. The more recent increase in TLIF over the traditional posterior lumbar interbody fusion (PLIF) has occurred secondary to the decrease in nerve root retraction required by TLIF to address the disc work resulting in less postoperative neuropraxia or radiculitis of the traversing nerve root. The upper lumbar spine is especially sensitive to nerve root retraction as you move more cranial toward the conus. Therefore, TLIF provides a safer alternative to PLIF in the upper lumbar spine from a posterior approach.


TLIF truly allows a single approach to provide a circumferential fusion. A surgeon is able to restore lordosis and  neuroforaminal height by placing a large interbody cage (PEEK, allograft, titanium). The interbody cage also provides significant anterior column support and fusion surface. The ability to place a pedicle screw construct and achieve a facet fusion as well as inter-transverse process fusion is a distinct advantage of the TLIF posterior approach. A “belt and suspenders” philosophy via a circumferential fusion to achieve high fusion rates is often necessary in tough fusion environments such as adjacent segment disease, and a TLIF approach provides this for this patient.3

Additionally, minimally invasive approaches may be used to perform TLIF surgery.4 The new tubular retractor systems
minimize paraspinal muscle damage but still allow the ability to perform laminectomy, discectomy and end plate preparation, facet fusion, posterolateral fusion and instrumentation through two small paramedian incisions. The MIS TLIF can even minimize working through difficult scar tissue as the paramedian incisions avoid the midline scarring from the previous procedure. The posterior approach also allows the ability to place percutaneous pedicle screw constructs on the the contralateral side from the disc preparation. Recent data suggest that good outcomes with earlier recovery and decreased postoperative pain can be achieved with MIS TLIF.

Certainly, there are other interbody fusion alternatives other than TLIF for this patient. However, TLIF has distinct advantages over the other approaches including ALIF and XLIF.

ALIF has several disadvantages when compared to TLIF. First, the operation requires the assistance of a general/vascular approach surgeon for most spinal surgeons. A significant amount of logistical planning is needed to get both surgeons’ operative time scheduled and coordinated. Second, the operative time and equipment necessary are significantly more involved for an ALIF when compared to TLIF. Furthermore, there are significant surgical risks introduced when adding the anterior approach to the procedure including retrograde ejaculation, injury to great vessels or ureter, increased ileus and sympathetic dysfunction. Stand alone constructs are utilized less frequently after significant pseudoarthrosis rates have been published in the literature without supplemental posterior fixation.5 Therefore, the posterior approach will likely be necessary to achieve adequate fixation; so why not accomplish all goals of the surgery through a single approach which is possible with a TLIF.

A more recent approach to the lumbar interbody space called an extreme lateral interbody fusion (XLIF) has been popularized in the past few years.6 This lateral retroperitoneal approach is an unfamiliar approach to most spinal surgeons and thus requires additional training. This extreme lateral approach dissects directly through the iliopsoas muscle to get into the disc space. This introduces risk of neurologic injury to the postganglionic lumbar plexus in the belly of the muscle. There has been a relatively high incidence of neuropraxia causing thigh numbness or pain in these patients. Additionally, there is no good literature to support stand-alone XLIF in these patients. This means that an intra-operative positional change and posterior instrumentation would be required. This significantly increases the operative time for these cases. Furthermore, a paucity of significant long term data exists in the literature regarding outcomes of XLIF.

In conclusion, a TLIF with posterolateral fusion and instrumentation is the best way to treat this patient. A standard (or
MIS) posterior approach to the lumbar spine via a TLIF allows the surgeon the ability to accomplish all goals of surgery for this patient via a single approach. It is a technique that has demonstrated a safe and effective option for patients requiring lumbar fusion.7

References
1. Kuisma M, Karppinen J, Niinimäki J, et al. Modic changes in endplates of lumbar vertebral bodies: prevalence and association with low back and sciatic pain among middle-aged male workers. Spine. 2007;32(10):1116-1122.

2. Fritzell P, Hägg O, Wessberg P, Nordwall A, Swedish Lumbar Spine Study Group. 2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group. Spine. 2001;26(23):2521-2532; discussion
2532-2534.

3. Madan SS, Harley JM, Boeree NR. Circumferential and posterolateral fusion for lumbar disc disease. Clin Orthop Relat Res. 2003;409:114-123.

4. Schwender JD, Holly LT, Rouben DP, Foley KT. Minimally invasive lumbar interbody fusion (TLIF) technical feasibility and initial results. J Spinal Disord Tech. 2005;18(Suppl):S1-6.

5. Pradhan BB, Bae HW, Dawson EG, Patel VV, Delamarter RB. Graft resorption with the use of bone morphogenetic protein: lessons from anterior lumbar interbody fusion using femoral ring allografts and recombinant human bone morphogenetic protein-2. Spine. 2006;31(10):E277-284.

6. Ozgur BM, Aryan HE, Pimenta L, Taylor WR. Extreme lateral interbody gusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion. Spine J. 2006;6(4):435-443.

7. Hackenberg L, Halm H, Bullmann V, Vieth V, Schneider M, Liljenqvist U. Transforaminal lumbar interbody fusion: a safe technique with satisfactory three to five year results. Eur Spine J. 2005;14(6):551-558. Epub Jan 26, 2005. 

• N Bhatia: a-2, Alphatec, Seaspine; c-2, Alphatec, Seaspine, Stryker; e-2, Alphatec, Seaspine, Stryker, Biomet; k-2, Spinewave.
• S Timon: a-3, Seaspine; c-2, DePuy, Stryker.
• E Wieser: a-3, Seaspine; c-3, e-3, Stryker.