CLINICAL STUDIES
TRANSFORAMINAL LUMBAR INTERBODY FUSION: SURGICAL TECHNIQUE AND RESULTS IN 24 PATIENTS Sean A. Salehi, M.D. Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
Rabih Tawk, M.D. Department of Neurological Surgery, University at Buffalo, The State University of New York, Buffalo, New York
Aruna Ganju, M.D. Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
Frank LaMarca, M.D. Department of Neurological Surgery, University of Michigan School of Medicine, Ann Arbor, Michigan
John C. Liu, M.D. Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
Stephen L. Ondra, M.D. Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
OBJECTIVE: The advantage of anterior column support and fusion in addition to pedicle fixation in patients with degenerative spinal disorders has become increasingly clear. With the increase in popularity of this treatment, a variety of techniques have been used to achieve the goal of anterior column support, fusion, and segmental instrumentation. Posterior lumbar interbody fusion has been used since the late 1940s in the treatment of degenerative lumbar spine. We evaluated a modification to posterior lumbar interbody fusion called transforaminal lumbar interbody fusion (TLIF). METHODS: A retrospective analysis was performed on 24 patients (9 women, 15 men) who underwent TLIF. The approach involved a unilateral laminectomy and inferior facetectomy at the level of fusion. The interbody fusion was achieved from this unilateral approach by performing discectomy, arthrodesis, and insertion of one or two titanium cages packed with autologous bone. The average age of the patients in this study was 42.6 ! 12.5 years. Five patients were smokers. Five cases were related to workmen’s compensation. Seventeen patients’ original symptoms were a combination of low back pain and radiculopathy. Ten patients had had a previous spine operation. RESULTS: Eleven patients had L4–S1 TLIFs. The rest of the patients had a single-level TLIF (L2–S1). Average intensive care unit and floor days were 1.1 ! 1.0 and 5.8 ! 2.2 days, respectively. The number of days to ambulation was 2.8 ! 1.6 days. There were a total of six self-limited complications in 24 patients (including one transient neurological complication). The average follow-up time was 16.9 ! 9.1 months. Twentytwo patients had solid fusions. A modified Prolo scale (4 worst, 20 best) was used to evaluate the clinical outcome. The average score was 16.1 ! 4.1. CONCLUSION: TLIF is a reliable and safe technique for interbody support that can be performed with excellent clinical outcome. In the authors’ experience, TLIF offers excellent exposure with minimal risk. This applies particularly in cases of repeat spine surgery, in which the presence of scar tissue makes traditional posterior lumbar interbody fusion techniques difficult or impossible. In addition, TLIF seems to be a viable alternative to anteroposterior circumferential fusion and/or anterior lumbar interbody fusion. KEY WORDS: Circumferential fusion, Lumbar spine, Transforaminal lumbar interbody fusion
Reprint requests: Sean A. Salehi, M.D., 233 East Erie Street, Suite 614, Chicago, IL 60611. Email:
[email protected] Received, December 18, 2002. Accepted, October 8, 2003.
Neurosurgery 54:368-374, 2004
H
DOI: 10.1227/01.NEU.0000103493.25162.18
igh pseudoarthrosis rates after simple discectomy and fusion without instrumentation have provided the impetus for several alternative techniques for fusion (15, 22, 24). Although posterior lumbar interbody fusion (PLIF) has been used since the 1940s (19), only recently has recognition of its theoretical advantages, perhaps with the benefit of accumulated experience, generated increased enthusiasm. Complementing this increased understanding were technical advances that gave rise
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to the possibility of achieving a circumferential fusion. The risk of PLIF approach-related injuries is well recognized (8, 25, 30). Anterior lumbar interbody fusion represents another alternative to a 360-degree spinal fusion but requires a separate anterior approach. In 1982, with the rationale of offering a secure fusion in a onestage operation, Harms and Rolinger (12) pioneered a modified PLIF technique called transforaminal lumbar interbody fusion (TLIF). Compared with the more traditional techniques,
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it provides several advantages by accessing the spinal canal and disc via a path that runs through the far-lateral portion of the vertebral foramen. Because minimal retraction on the nerve roots and dural sac is required, the surgical risk for neurological deficit is significantly lower. In addition, TLIF achieves a single-stage circumferential fusion through only a posterior approach. As interbody techniques have been advocated to improve fusion rates and such procedures have become increasingly common, more patients require fusion after an initial decompression (9). It is our belief that TLIF is a reliable method not only to achieve a circumferential fusion but also to provide a safe and effective fusion with less violation of the posterior elements. It offers unique advantages in revision patients in whom scar tissue makes PLIF techniques difficult. In this report, we describe the TLIF technique, which has been addressed in only a few published works (12, 25, 33), and discuss our clinical experience in the management of the lumbar spine.
PATIENTS AND METHODS The clinical characteristics and operative outcomes of patients treated with TLIF at our institution were reviewed retrospectively. The patients’ clinical examinations, diagnostic imaging studies, hospital charts, and office records were analyzed for data collection. All patients underwent a transforaminal approach. TSRH or CD Horizon pedicle screws and Pyramesh cages (Medtronic Sofamor Danek, Inc., Memphis, TN) were used for the instrumentation. Follow-up review consisted of office visits with clinical examination and evaluation of x-rays by neurosurgery and radiology staff. Telephone interviews supplemented data in the chart. Successful fusion was defined as 1) absence of halo around the screws, 2) presence of bilateral continuous trabecular bone bridge between the fused segments on anteroposterior x-rays, and 3) lack of motion on flexion/extension films.
Patient Population In a 3-year interval of spine team practice in our institution, 24 patients received TLIF (Table 1). Their average age was 42.6 ! 12.5 years, and there were 15 men and 9 women. The original symptoms of 17 patients were a combination of low back pain and radiculopathy, and all patients were considered candidates for fusion. Ten patients (42%) had undergone previous spine surgery, and five (21%) were smokers. Before surgery, five patients (21%) were involved in claims for workmen’s compensation. Six patients had low back pain, one had lower-extremity radiculopathy, and 17 had a combination of the two. TLIF was performed at one vertebral level in 12 patients and at two levels in the remaining 12. Thirteen patients were diagnosed with spondylolisthesis, eight had spondylosis, two exhibited vertebral fractures and disc disruption, and one had a giant cell spinal tumor of the posterior elements with a moderately degenerated disc. Scoliosis patients were excluded. This group was followed up for a period averaging 16.9 months (range, 3–34 mo), and results were assessed. We
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used a modified Prolo scale (Table 2) with the fusion rate and patient satisfaction questionnaire to evaluate the outcomes.
Technique The patient is placed in the prone position (Fig. 1). Posterior spinal elements are exposed through a midline longitudinal incision. A subperiosteal dissection of the paraspinous muscles is completed to the transverse processes. Pedicle screws are sized and inserted under frameless stereotactic navigational or C-arm x-ray guidance before decompression to minimize blood loss and achieve distraction. If radiculopathy is present, the spinal canal is entered through a unilateral laminectomy and inferior facetectomy on the side of the radicular pain. If no radiculopathy is present, the side is chosen arbitrarily. The interspinous ligament as well as the ligamentum flavum on the opposite side is left intact. The exiting nerve root is identified and protected from surgical trauma. The thecal sac is gently retracted medially if necessary. Discectomy is performed through this unilateral approach. After the initial discectomy, gradual distraction is applied to the pedicle screws on the opposite side. An osteotome is used to remove the posterior lateral lip of concave bone to achieve a flat endplate surface. Dissection is completed, and the endplate is arthrodesed to the bleeding bone without violating the endplate entirely. The previously harvested cancellous bone is packed inside the interbody space in the anterior and lateral portions as well as into the cages. Cages are sized for maximum height. The first cage is placed into the disc space and slid anteriorly to the contralateral side. A second cage is seated next to the first one to line them up side by side. After insertion of the bilateral cages from a unilateral approach, the disc space distraction is released. The construct is compressed to establish an optimum graft-bone interface and to reestablish lumbar lordosis at the segments operated on. The rod-screw system is tightened and cross-linked. Cancellous iliac bone graft is laid over the transverse processes after adequate decortication to establish a circumferential fusion (Fig. 2).
RESULTS Perioperative Results The TLIF technique provided excellent exposure in all patients. Through a single incision, it allowed us to perform full decompression of the nerve roots and dural sac, followed by 360-degree stabilization. The average blood loss was 1612 ! 1038 ml (1412.5 ml for single-level fusion and 1812.5 ml for two-level fusion). The hospital stay averaged 7 ! 2.2 days. After surgery, patients were mobilized within 2.8 ! 1.6 days. In general, no rigid external orthosis was needed unless significant osteoporosis was present (three patients). Complications are listed in Table 1. One patient had a transient left foot drop. The patient is a 39-year-old man with no previous surgery who had a two-level L4–L5, L5–S1 TLIF and a left L5 paresis (3/5 motor strength). His intraoperative course was unremarkable. His postoperative imaging did not show any
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TABLE 1. Summary of transforaminal lumbar interbody fusion groupa Followup (mo)
Fusion
Prolo scale (P/F/E/M)
None
3
34
Yes
19 (4/5/5/5)
Yes
L4 –L5
None
3
27
Yes
17 (3/5/5/4)
Yes
Yes
L4 –L5, L5–S1
None
2
21
Yes
18 (5/3/5/5)
Yes
Spondylosis
No
L4 –L5, L5–S1
None
2
38
Yes
16 (3/5/4/4)
Yes
M/61
Spondylolisthesis
Yes
L4 –L5, L5–S1
Ileus
4
8
Yes
16 (4/3/4/5)
Yes
6
M/41
Spondylosis
No
L5–S1
None
1
6
Yes
17 (4/3/5/5)
Yes
7
F/57
Spondylosis
No
L4 –L5
Sutured drain
2
16
Yes
19 (5/5/5/4)
Yes
8
M/39
Spondylolisthesis
No
L4 –L5, L5–S1
Transient L5 paresis
2
24
Yes
12 (3/3/2/4)
No
9
F/57
Spondylolisthesis
No
L4 –L5
None
4
24
Yes
18 (5/4/4/5)
Yes
10
F/33
Spondylolisthesis
No
L5–S1
None
4
18
Yes
20 (5/5/5/5)
Yes
11
M/53
Spondylolisthesis
Yes
L4 –L5, L5–S1
None
2
20
Yes
17 (4/4/4/5)
Yes
12
M/49
Spondylosis
Yes
L3–L4
None
2
21
Yes
20 (5/5/5/5)
Yes
13
M/37
Spondylosis
No
L4 –L5
None
3
8
Yes
17 (4/3/5/5)
Yes
14
M/45
Posterior laminarpars fracture
No
L2–L3
None
7
9
Yes
6 (1/2/1/3)
Uncertain
15
M/41
Spondylolisthesis
No
L4 –L5, L5–S1
None
2
24
Yes
17 (4/3/5/5)
Uncertain
16
M/62
Spondylolisthesis
Yes
L4 –L5
Pulmonary embolus
2
13
Yes
17
M/42
Spondylolisthesis
No
L4 –L5
None
2
26
Yes
19 (5/4/5/5)
Yes
18
F/21
Spondylolisthesis
Yes
L4 –L5, L5–S1
None
2
10
Yes
16 (3/4/4/5)
Yes
19
F/66
Posterior laminarpars fracture
Yes
L5–S1
Dural tear
8
16
Yes
9 (2/3/3/1)
No
20
F/42
Spondylolisthesis
No
L4 –L5, L5–S1
None
2
10
Yes
19 (4/5/5/5)
Yes
21
F/24
Spondylolisthesis
No
L4 –L5, L5–S1
Pseudomeningocele
3
9
Yes
19 (4/5/5/5)
Yes
22
M/41
Spondylosis
Yes
L2–L3, L3–L4
None
2
3
No
7 (2/2/2/1)
No
23
M/40
Spondylosis
Yes
L4 –L5
None
2
17
Yes
20 (5/5/5/5)
Yes
24
F/37
Spondylolisthesis
No
L4 –L5, L5–S1
None
2
4
No
12 (3/3/3/3)
Uncertain
TLIF levels
Giant cell tumor of posterior elements
No
L4 –L5, L5–S1
M/38
Spondylosis
Yes
3
M/49
Spondylolisthesis
4
M/20
5
Sex/age (yr)
1
F/29
2
a
Patient’s answer to: “would you do it again?”
Walking (d)
Previous surgery
Patient no.
Diagnosis
Complications
TLIF, transforaminal lumbar interbody fusion; P, pain; F, functional status; E, economic status; M, medication.
foraminal stenosis or screw malposition. He had a complete recovery from this foot drop. This recovery occurred a few months after surgery, leading us to believe that he might have incurred a stretch injury during the distraction.
Postoperative Results After an average follow-up period of 16.5 ! 9.8 months, solid fusion was achieved in 22 patients, whereas pseudarthrosis was documented in two patients, manifested by pain
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and radiographic findings. Both of these patients were smokers, had two-level TLIFs, and required return to the operating room for arthrodesis across the pseudoarthrosis and placement of larger-diameter screws in addition to internal bone stimulators. The time to diagnosis and time to return to the operating room for these patients were at 3 and 4 months after surgery. Work status is recorded in Figure 3. The modified Prolo scale (23) (4 worst, 20 best) average was 16.1 ! 4.1 (Table 2; Fig. 4). On the patient satisfaction questionnaire, 17 patients
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TABLE 2. Modified Prolo scalea Score Pain P1 P2 P3 P4 P5
Description Unbearable pain Severe pain Moderate pain Mild pain No pain
Functional status F1 Total incapacity F2 Can do activities at home F3 Activities outside home with limitation F4 Limitation with strenuous activities F5 Able to do everything Economic status E1 Unable to do tasks around home E2 Able to do tasks around home but unable to work E3 Able to work at sedentary capacity E4 Able to work at moderate capacity E5 Able to work at heavy capacity or previous job Medication M1 M2 M3 M4 M5
10 or more hydrocodone tablets or equivalent 6 –9 hydrocodone tablets or equivalent 3–5 hydrocodone tablets or equivalent Regular NSAIDs or occasional hydrocodone None or occasional hydrocodone
Total a
NSAIDs, nonsteroidal anti-inflammatory drugs.
(71%) were satisfied with the results of the intervention and would willingly undergo the same operation, 3 (12.5%) were satisfied but were not sure whether they would undergo the same operation again, 3 (12.5%) were not satisfied with the results and would not be willing to undergo a similar operation, and 1 was unreachable for this follow-up questionnaire.
DISCUSSION The rationale for fusion in the treatment of degenerative lumbar spine disease remains controversial. There is an emerging consensus, however, to perform fusion along with any concurrent decompressive procedure for instability or discogenic back pain (5, 6). Alternatively, interbody fusion with pedicle instrumentation has rapidly gained popularity. Nevertheless, attention has been focused on reconstruction of the anterior column, because it shares 80% of the lumbar spine load, and such reconstruction places the interbody graft under compression and increases the fusion rate (5, 7, 26, 33). Anterior lumbar interbody fusion frequently requires involvement of an access surgeon as well as a separate approach
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from the posterior instrumentation (21). PLIF is also commonly used but requires bilateral exposure with loss of the posterior tension band at the level of fusion. It decreases the bony surface for posterior fusion, requires significant retraction of the neural elements, and cannot be performed safely in a repeat case secondary to scar tissue formation. TLIF technique provides a single posterior approach for a 360-degree fusion without the aforementioned limitations of other techniques. Currently, the accumulated experience coupled with technological evolution provides a greater range of choices to achieve internal fixation with less violation of normal tissues. TLIF offers a new window of opportunity to access the spine while leaving the contralateral laminar surface intact as an additional surface for bone graft placement (13). By preserving the spinous processes and the contralateral yellow ligament, the original posterior tension band is preserved. By allowing circumferential fusion, the transforaminal approach achieves a stiffer construct than either an anterior or posterior fusion alone (10, 16, 17, 31). Compared with the combined anterior and posterior approach, it reduces morbidity, length of hospital stay, and expenses (2, 4, 25). Indeed, it represents an alternative method for performing a circumferential fusion through one incision. Although this report is not a prospective study, our clinical experience with TLIF has demonstrated that the technique can reduce the approach-related neurological morbidity associated with traditional PLIF, particularly when there is a history of previous surgery (25, 27). By using TLIF, this potential risk can be avoided by operating on the opposite site, and the nerve can be safely mobilized by approaching it from the adhesion-free side, minimizing nerve root and dural retraction (14). As a modified PLIF, TLIF maintains the inherent benefits of the posterior approach. It dynamically decompresses neural structures and, by distraction/compression of the involved lumbar levels, reconstitutes the normal sagittal anatomic relation between the motion segments (19). Finally, like PLIF, TLIF enhances fusion through elimination of disc space motion and restoration of disc height (31). Biomechanically, this technique allows restoration of the spine in the sagittal plane balance (3). In addition, the large area of bony contact between the grafts and the vertebral bodies improves the likelihood of a successful fusion (18). The pedicle-based segmental fusion provides control over the vertebrae in the sagittal, coronal, and axial planes (1, 5, 28, 29, 32, 34). In addition to avoiding compression loss during tilting and minimizing graft retropulsion, posterior instrumentation achieves better segmental control with early stabilization (5, 14). As a result, the interbody fusion immediately produces a biomechanically stable postoperative spine, enhancing the opportunity for fusion (13). On a purely technical level, when using the PLIF technique, the surgeon is limited to the lower lumbar levels (13). Because the conus lacks the flexibility for retraction needed in a PLIF, in which one must retract the dural sac out to the midline at higher levels, this can result in neurological complications.
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FIGURE 1. Diagrams showing steps in performing the TLIF procedure. A, lumbar pedicle screws are inserted in a standard fashion. B, slight distraction is performed opposite the intended decompression side. The hatched area denotes the inferior facet complex that is going to be removed. C, inferior facetectomy is performed, and posterior lateral lip/ anulus complex is cut out. D, the endplates are arthrodesed, and the posterior vertebral body is made parallel to the rest of the endplate with an osteotome. E, bone graft is placed anterior in the disc space. F, the interbody graft is placed in the disc space. G, the interbody graft is pushed over to the opposite side with a curved half-moon instrument. H, the second interbody graft is placed in the disc space. I, distraction is removed from the contralateral screws and compression is performed bilaterally to achieve a good graft-endplate interface and to establish lordosis in the sagittal plane. J, posterolateral arthrodesis is performed, and bone graft is laid over it (courtesy of Medtronic Sofamor Danek, Inc., Memphis, TN).
TLIF can be performed at any lumbar level below L1, because it avoids significant retraction of the dura and conus medullaris (13). The appropriate laminectomy, inferior facetectomy, and foraminotomy enable the surgeon to relieve all neural compression (19). Moreover, the lateral approach allows vigorous undercutting of the endplate, optimizing fusion (25). Although more steps are involved in a TLIF procedure than PLIF, the distraction permits an easy and safe decompression of the disc space (5). In addition, by achieving a stable construct with the vertebrae, the pedicle-screw system can be
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used effectively for segmental distraction to restore disc height and lumbar lordosis (14). Pedicle screw distraction depends on the bone quality. Sequential distraction must be done carefully to avoid pedicle fracture (11, 25). The ability to restore lordosis to degenerative segments cannot be overstated. Because the cages are inserted in the middle to anterior third of the disc space, pedicle screw compression increases lordosis. This is in contrast to the PLIF technique, which can potentially reduce the lordosis and further decrease sagittal balance. Because the primary pathological condition in spondylolisthesis is a poor posterior tension band, decompressive surgery
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nique may provide a second line of defense against pseudarthrosis (31). Even though we did not compare our fusion rate with that of a control group in our institution, the results are similar to recent historical data with this type of procedure. Lowe et al. (20) describe a 90% fusion rate in 40 patients.
CONCLUSION
FIGURE 2. A, postoperative anteroposterior x-ray of a patient after the TLIF procedure. Note the midline position of the cages. B, postoperative lateral x-ray of the same patient. One can see the anteriorly placed cages.
FIGURE 3. Graph showing work status of the patients after surgery.
FIGURE 4. Graph showing clinical outcome of patients according to the Prolo expanded functional scale. Categories include 4 to 8, poor; 9 to 12, fair; 13 to 16, good; and 17 to 20, excellent.
invariably results in gross segmental instability from the loss of entire posterior stabilizing structures in the face of incompetent anterior support (16, 31). When posterior lumbar fusion is combined with anterior interbody fusion, it results in increased fusion rates as well as improved stability and reductions (13). This technique is particularly useful in cases with more unstable segments, malalignment, or long-segment fusion (14). The addition of segmental pedicle screw fixation facilitates the reduction of listhesis and improves spinal biomechanics (26). It also should be kept in mind that this tech-
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This study demonstrates that TLIF can be performed safely and effectively to achieve circumferential fusion. It requires nerve root and thecal sac retraction and achieves a generous decompression. Midrange follow-up outcomes are particularly encouraging. At the present time, the conclusion can be drawn that this technique is a safe and effective alternative to other types of interbody fusion procedures. It has the advantage of achieving a 360-degree fusion from a single posterior approach. It accommodates decompression, restoration of lumbar lordosis, disc height restoration, and augmentation of posterior tension band via a screw-rod construct. The unilateral approach also is very helpful in patients who have undergone a previous operation, often providing virgin tissue planes for dissection. Although this technique can be safely applied in patients requiring 360-degree fusion, it is challenging and requires a steep learning curve. The selection process for patients requiring this procedure should be very strict, and TLIF is not recommended in cases in which a simpler and less involved technique might achieve the goal.
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14. Jun BY: Posterior lumbar interbody fusion with restoration of lamina and facet fusion. Spine 25:917–922, 2000. 15. Katz JN, Lipson SJ, Chang LC, Levine SA, Fossel AH, Liang MH: Seven- to 10-year outcome of decompressive surgery for degenerative lumbar spinal stenosis. Spine 21:92–98, 1996. 16. Kim SS, Denis F, Lonstein JE, Winter RB: Factors affecting fusion rate in adult spondylolisthesis. Spine 15:979–984, 1990. 17. Kozak JA, O’Brien JP: Simultaneous combined anterior and posterior fusion: An independent analysis of a treatment for the disabled low-back pain patient. Spine 15:322–328, 1990. 18. Lin PM: Posterior lumbar interbody fusion technique: Complications and pitfalls. Clin Orthop 193:90–102, 1985. 19. Lin PM, Cautilli RA, Joyce MF: Posterior lumbar interbody fusion. Clin Orthop 180:154–168, 1983. 20. Lowe TG, Tahernia AD, O’Brien MF, Smith DAB: Unilateral transforaminal posterior lumbar interbody fusion (TLIF): Indications, techniques and 2-year results. J Spinal Disord Tech 15:31–38, 2002. 21. Muhlbauer M, Pfisterer W, Eyb R, Knosp E: Minimally invasive retroperitoneal approach for lumbar corpectomy and anterior reconstruction: Technical note. J Neurosurg 93[Suppl 1]:161–167, 2000. 22. Nakai O, Ookawa A, Yamaura I: Long-term roentgenographic and functional changes in patients who were treated with wide fenestration for central lumbar stenosis. J Bone Joint Surg Am 73A:1184–1191, 1991. 23. Prolo DJ, Oklund SA, Butcher M: Toward uniformity in evaluating results of lumbar spine operations: A paradigm applied to posterior lumbar interbody fusions. Spine 11:601–606, 1986. 24. Rish BL: A comparative evaluation of posterior lumbar interbody fusion for disc disease. Spine 10:855–857, 1985. 25. Rosenberg WS, Mummaneni PV: Transforaminal lumbar interbody fusion: Technique, complications, and early results. Neurosurgery 48:569–575, 2001. 26. Schlegel KF, Pon A: The biomechanics of posterior lumbar interbody fusion (PLIF) in spondylolisthesis. Clin Orthop 193:115–119, 1985. 27. Simmons JW: Posterior lumbar interbody fusion (PLIF), in Frymoyer JW, Ducker TB, Hadler NM, Kostuik JP, Weinstein JO, Whitecloud TS III (eds): The Adult Spine: Principles and Practice. New York, Raven Press, 1991, vol 2, pp 1961–1987. 28. Simmons EH, Capicotto WN: Posterior transpedicular Zielke instrumentation of the lumbar spine. Clin Orthop 236:180–191, 1988. 29. Steffee AD, Biscup RS, Sitkowski DJ: Segmental spine plates with pedicle screw fixation: A new internal fixation device for disorders of the lumbar and thoracolumbar spine. Clin Orthop 203:45–53, 1986. 30. Stonecipher T, Wright S: Posterior lumbar interbody fusion with facet-screw fixation. Spine 14:468–471, 1989. 31. Suk SI, Lee CK, Kim WJ, Lee JH, Cho KJ, Kim HG: Adding posterior lumbar interbody fusion to pedicle screw fixation and posterolateral fusion after decompression in spondylolytic spondylolisthesis. Spine 22:210–220, 1997. 32. Voor MJ, Mehta S, Wang M, Zhang YM, Mahan J, Johnson JR: Biomechanical evaluation of posterior and anterior lumbar interbody fusion techniques. J Spinal Disord 11:328–334, 1998. 33. Whitecloud TS III, Roesch WW, Ricciardi JE: Transforaminal interbody fusion versus anterior-posterior interbody fusion of the lumbar spine: A financial analysis. J Spinal Disord 14:100–103, 2001. 34. Zielke K, Strempel AV: Posterior lateral distraction spondylodesis using the twofold sacral bar. Clin Orthop 203:151–158, 1986.
COMMENTS
T
he authors performed transforaminal lumbar interbody fusion (TLIF) in 24 patients and achieved a solid orthosis in 22 patients. However, the follow-up is short: in some patients, only 2 months. Complications were minimal and patient satisfaction was acceptable. The authors conclude that this is a safe and effective alternative to other types of interbody fusion procedures.
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The contralateral side can be used in patients who have undergone surgical exploration on one side. Theoretically, the advantage of the procedure is that the posterior tension band remains intact. The authors emphasize that nerve roots should not be retracted rigorously. Yet, one patient had L5 radiculopathy after surgery. This procedure is not necessarily a better approach to other 360-degree operations, but it is a good alternative. As with any fusion procedure, careful patient selection contributes to a successful outcome. Volker K.H. Sonntag Phoenix, Arizona
S
alehi et al. have clearly and succinctly reported their recent experience with TLIF. This technique, although associated with a relatively lengthy hospital stay, seems to be a viable alternative to combined anterior and posterior operations and posterior lumbar interbody fusion operations. Its advantages and disadvantages are portrayed fairly by Salehi et al. This is a clear and meticulous documentation of the authors’ experience with this relatively new technique. Edward C. Benzel Cleveland, Ohio
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alehi et al. address the indications, surgical technique, complications, and results of the TLIF technique. It is the authors’ contention that the TLIF procedure is a safe, effective alternative to both posterior lumbar interbody fusion and anterior lumbar interbody fusion to achieve the goal of anterior column support, fusion, and segmental instrumentation. They claim that this is because it is a single posterior approach to the spinal canal and disc space from a far lateral corridor that runs through the intervertebral foramen, thus allowing for a safe approach to the disc space with minimal retraction of the neural elements and, in the case of reoperations, avoidance of midline scar tissue. The authors retrospectively reported the results of 24 TLIF procedures performed over a 3-year period. There were heterogeneous indications, including both trauma and tumor. Both one- and two-level fusions were included in their analysis, with follow-up of 16.5 ! 9.8 months. One patient in their series had a transient neurological deficit, and 22 of the 24 patients achieved a solid fusion. Both failed fusions were in smokers who underwent two-level fusions. In short, the authors have provided us with an excellent description of the TLIF technique and addressed its efficacy and safety compared with other types of interbody fusion techniques. However, longer follow-up will be needed to truly assess the clinical efficacy of achieving 360-degree stabilization with this technique. Paul R. Cooper Anthony K. Frempong-Boadu New York, New York
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