|Year : 2014 | Volume
| Issue : 1 | Page : 191-196
Posterolateral fusion versus posterior interbody fusion in adult lumbar isthmic spondylolisthesis
Hosam A.M. Habib
Department of Neurosurgery, Faculty of Medicine, Menoufia University, Shibin Al Kawm, Egypt
|Date of Submission||20-Nov-2013|
|Date of Acceptance||05-Jan-2014|
|Date of Web Publication||20-May-2014|
Hosam A.M. Habib
MD, PhD, Department of Neurosurgery, Faculty of Medicine, Menoufia University, Shibin Al Kawm, 27 Dr. Sayed Fahmy St. Sidi Gaber Alexandria 21431
Source of Support: None, Conflict of Interest: None
The aim of this study is to assess and compare the outcomes of posterior lumbar interbody fusion (PLIF) and posterolateral fusion (PLF) in adult isthmic spondylolisthesis.
Both PLIF and PLF have been used widely in the treatment of lumbar degenerative spinal diseases. Although PLIF has theoretical and demonstrable advantages over PLF, many authors did not observe this and report that outcomes of both surgical methods are comparable.
Materials and methods
Fifty patients with lumbar spondylolisthesis were operated for isthmic spondylolisthesis complaining of low back pain with or without sciatica and neurogenic claudication. The patients were allocated randomly to two groups according to the mode of bony fusion into PLIF and PLF groups. The two groups were statistically similar with respect to demographic and clinical data.
No significant differences were found between PLIF and PLF in blood loss, short-term postoperative clinical result, or complications, but the operation time was longer with PLIF. Postoperative long-term visual analogue scale (VAS) for back pain, the Oswestry disability index, and fusion rates were significantly better in PLIF.
PLIF seems to be a better bone fusion technique than PLF in the management of isthmic spondylolisthesis.
Keywords: Lumbar fusion, posterior lumbar interbody fusion, posterolateral lumbar fusion, spondylolisthesis
|How to cite this article:|
Habib HA. Posterolateral fusion versus posterior interbody fusion in adult lumbar isthmic spondylolisthesis. Menoufia Med J 2014;27:191-6
|How to cite this URL:|
Habib HA. Posterolateral fusion versus posterior interbody fusion in adult lumbar isthmic spondylolisthesis. Menoufia Med J [serial online] 2014 [cited 2017 Dec 14];27:191-6. Available from: http://www.mmj.eg.net/text.asp?2014/27/1/191/132800
| Introduction|| |
Isthmic spondylolisthesis surgery aims to accomplish fusion and neural decompression with or without instrumentation, to correct the present instability, and alleviate pain. In 1889, Hadra  described the use of wires in treating spinal deformities caused by Potts disease. Later, Albee  and Hibbs  each presented variable successful methods to prevent progressive kyphosis in Potts patients and scoliosis treatment utilizing autogenous bone grafts derived from the spinous processes or tibia or iliac crest, which were placed on-lay of decorticated laminae to achieve fusion. Unfortunately, the high incidence of pseudoarthrosis in their series necessitated prolonged postoperative immobilization and external orthosis. Posterolateral fusion (PLF) was an improvement of these techniques, where the side of the vertebral bodies and transverse process were decorticated and bone grafts were placed on-lay to allow intertransverse process fusion, minimizing the risk of neobone formation into the neural canal. Because of the ease and good fusion rates with PLF, it has and still remains one of the largely used posterior fusion techniques .
Cloward , in 1952, placed the bone grafts anteriorly between the vertebral bodies, promoting fusion to occur through the disk space, while decompressing the spinal canal posteriorly by performing a laminectomy. This was the first introduction of the posterior lumbar interbody fusion (PLIF) technique. The possible risk of root injury caused by excessive retraction minimized the use of this technique by many surgeons. In the past two decades, there has been a resurge in the use of this technique because of innovations in the surgical instruments, which minimizes the amount of retraction and possibility of nerve injury, while providing the theoretical advantages of PLIF including preservation of sagittal balance and disk height ,,.
To date, both PLF and PLIF are widely used fusion techniques, applied during spondylolisthesis surgery. Several studies have shown that PLIF has theoretical and demonstrable advantages over PLF ,,,,,,,,,,, whereas others report that the outcomes of both techniques are comparable ,,. Thus, the aim of this series is to compare the outcomes of PLIF and PLF.
| Materials and Methods|| |
Fifty patients with lumbar spondylolisthesis in the period between 2007 and 2011 were operated for isthmic spondylolisthesis. The surgical indication was persistent low back pain with or without neurological compromise that failed to respond to 6 months of conservative treatment. These patients were then allocated randomly to two groups according to the mode of bony fusion into PLIF and PLF groups. The two groups were similar with respect to grade of slipping, sex, age, and activity.
After induction of anesthesia, the patients were placed in the prone position. Posterior spinal column and the transverse processes were exposed through a posterior midline incision. Excision of mobile laminae, including the attached spinous processes and inferior facet, was performed in addition to medial facetectomy and foraminotomy to achieve proper thecal sac decompression as well as the roots existing at the motion segment. The excised bone was kept for use as bone grafts after careful removal of any attached soft tissue. Pedicle screw instrumentation was carried out in all patients with care not disrupt the upper facet joint.
In the PLIF group, an almost complete diskectomy and end-plate decortication was performed. Intervertebral disk space spreaders were then sequentially inserted and rotated to restore the normal disk space height. The disk space was then packed with the laminectomy bone, starting with the smaller bone chips anterior and larger ones mainly consisting of a large portion of the lamina, which is sculptured to fit anterior to the posterior vertebral borders, to act as a mechanical barrier to prevent escape of the smaller bone chips.
In the PLF group, high-speed drilling of the side of the remaining parts of the facet joints and transverse processes was performed bilaterally for decortication, followed by on-lay placement of laminectomy bone chips bilaterally. All patients used a soft lumbar corset for 3 months.
A minimum 18-month follow-up was available in all patients. For clinical evaluation, the patients visual analogue scale (VAS) scores for leg and back pain were administered at 6-monthly intervals, where the sixth postoperative month was considered the short-term VAS and those obtained at 18 months or later were considered the long-term VAS.
The Oswestry disability index (ODI)  questionnaire with its 10-item ordinal scale (pain intensity; personal care; ability to lift, walk, sit, stand, and sleep; sex life; social; and traveling; each item had six responses, where 0 was normal functionality and 5 the worst, and the sum of these is multiplied by two, thus providing a worst sum of 100 and a best of 0) was administered in a similar manner as the VAS .
Anteroposterior, lateral, and dynamic radiographs views were performed at 3, 6, 12, and 18 month postoperatively for all patients, and, if possible, in subsequent visits, where the last was considered the final follow-up. Rarely computed tomography was utilized when fusion was questionable. 'Solid bony fusion' was considered when a bridging bony trabecular continuity and a mobility of less than 4° were documented radiographically . In this study, failure to achieve this by the end of the first postoperative year was considered a failure of fusion. Posterolateral spinal fusion was evaluated according to the Christensen classification , where the formation of a continuous intertransverse bony bridge at a minimum of one of the two sides indicated fusion at that level. The operative duration, postoperative complications, and need for a second surgery were assessed.
The data were collected and analyzed using the Statistical Package for Social Sciences (SPSS, version 17; SPSS Inc., Delaware, USA) software. Arithmetic mean, SD, number, and percent were calculated. For categorized parameters, the χ2 -test was used, whereas for numerical data, the t-test was used to compare two groups. The level of significance was 0.05.
| Results|| |
The study included 29 female and 21 male patients, with mean ages of 52.7 years in the PLIF group and 51.3 years in the PLF group. The two groups were statistically similar with respect to demographic and clinical data, which are summarized in [Table 1].
The minimum follow-up period in each group was 18 months. The mean follow-up period was 26 months (range, 18-46 month) for the PLIF group and 29 months (range, 20-52 month) for the PLF group; the difference between the two groups was not significant.
The mean operative time for single-level surgery was 110 min in the PLF group (range, 85-125 min) compared with 125 min (range, 100-140 min) in the PLIF group, whereas the mean operative time for double-level surgery was 140 min (range, 110-155 min) in the PLF group and 160 min (range, 140-185 min) for the PLIF group; these differences were significant (P < 0.05). Perioperative blood loss was 750 ml (range, 250-1100 ml) for patients in the PLF group and 850 ml (range, 450-1400 ml) for patients in the PLIF group: this difference was not significant [Table 2].
There were three perioperative complications in the PLF group: a dural tear in a patient, and postoperative aggravation of the radicular pain in two patients. In the PLIF group, two patients had probable dural tears detected postoperatively by the occurrence of postural headache and cerebrospinal fluid through the drain; both were self-limited and required no intervention. In addition, four patients had transient de-novo parethesia, related to radicular manipulation and not actual root injuries, and they resolved spontaneously [Table 2].
Radiological fusion was confirmed in 24 patients (96%) of the PLIF group [Figure 1] and 17 patients (68%) in the PLF group [Figure 2] by the end of the first year. None of the patients who failed to achieve fusion had achieved it in their later visits despite incomplete resorption of the bone chips. The difference in the prevalence of fusion between the two groups was significant (P = 0.0442).
The average short-term visual analogue score for leg and back pain, measured at the sixth postoperative month, showed improved leg pain from 65 preoperatively to 30, whereas back pain improved from 73 preoperatively to 35 in the PLF group and the PLIF leg pain from 68 to 24 and back pain 75 to 30, but the difference between the two groups was not significant (P > 0.05). The final follow-up visual analogue score for leg and back pain showed improved leg pain in both PLF and PLIF groups to 22 and 25, respectively, whereas back pain improved in PLIF to 22 and increased to 40 in the PLF group; the difference between the two groups was significant (P = 0.002) in terms of long-term VAS for back pain [Table 3].
There was a marked reduction in the preoperative ODI [Table 4] from that recorded in the final examination. The PLF group had a mean preoperative ODI of 38.5 (range, 22-82) that was reduced to a mean of 25.1 (range, 2-55) at the final postoperative follow-up. However, in the PLIF group, it was reduced from 36.9 (range, 24-68) preoperatively to 16.2 (range, 0-36). The difference between the two groups was significant (P = 0.0058).
Eight patients (16%) underwent a second surgery, all of whom had radiological nonfusion: a patient (4%) from the PLIF group because of the occurrence of pseudoarthrosis and persistence of severe back and seven patients (24%) from the PLF group for persistent severe back pain and, loosening of the screw caps in two cases and screw breakage in one [Figure 3]. In their second surgery, PLIF was performed. The difference between PLIF and PLF was significant (P < 0.002).
| Discussion|| |
After Clowards'  first description of PLIF in 1952, he later published the data of 165 patients who underwent PLIF for spondylolisthesis, where a fusion rate of 93% and excellent clinical results in 95% of the patients were recorded . In another series of 465 patients who were studied by Lin  in whom PLIF was performed for various spinal degenerative pathologies, a satisfactory clinical outcome was found in 82% of the patients, whereas 88% had radiographic fusion.
Ray  reported a radiographic fusion rate of 96%, and a clinical outcome of good to excellent in 65% in his series after a follow-up duration of 2 years; he reported that PLIF reduced the mechanical stresses in the fused segment and prevented the possible leakage of chemical irritants (such as phospholipoic acid from the disk space), and led to a reduction in the pseudoarthrosis rate with an improvement of clinical outcome, especially if augmented by instrumentation. Similarly, Brantigan et al.  reported a 98.9% fusion rate and 86% clinical success in their PLIF series when augmented by posterior instrumentation.
Dantas et al.  reported that PLIF augmented by transpediclular screws led to better clinical outcomes, Prolo economic, and functional scales, and fewer complications when compared with PLF. This is in agreement with the results obtained in this study.
La Rosa et al .  support the view that PLIF confers a superior mechanical strength to the spinal construct, whereas in PLF, there is a progressive reduction in the correction achieved, but not to the extent to affect the clinical outcome.
Deuhoux et al.  reported that fusion rates are directly proportional to the degree of slippage and disk height, while not affecting the functional outcome. Hence, they prefer to use PLIF for high-grade spondylolisthesis requiring reduction or if the disk space is still high, whereas in low-grade slippage, or narrow disk spaces, PLF is preferable.
Musluman et al.  reported a clinical outcome of good or excellent in 22 (88%) cases in the PLIF group and 19 (76%) cases in the PLF group. Fusion ratios were 100% in the PLIF group and 84% in the PLF group. Both lumbar lordosis and the segmental angle showed greater improvement in the PLIF group, but there was no difference in the complication rates for each group.
Ekman et al.  reported that the results of PLIF and PLF in the surgical management of adult isthmic spondylolisthesis were comparable in the patient outcome at the end of their 2-year follow-up. In this study, there was a significant difference between both techniques in favor of PLIF, and this was the basis for its application in the patients who needed a second surgery. In contrast, Mada n et al.  reported better clinical outcome in low grades of isthmic spondylolisthesis with PLF than PLIF, although they report that PLIF fusion is more predictable in maintaining correction and achieving union.
Wu et al.  reported a significant reduction in both pain and Oswestry disability indices for both PLIF and PLF groups, where 88% of the patients in the PLF group and 91% of the patients in the PLIF group had radiological fusion, which was statistically insignificant. Although both techniques were comparable in terms of the outcome, PLF had greater tendency for hardware failure than the PLIF group, which was statistically insignificant.
There is a general consensus that PLIF is a cumbersome procedure, where the surgeon might be faced with excessive bleeding and a protracted operative time , but with practice, it should not pose a technical challenge. In the present study, there was no significant difference in the perioperative blood loss between the PLF group and the PLIF group. However, impacting the bone and sculpturing the most dorsal bone graft did lengthen the procedure by an average of 15 min per level. These results are similar to those obtained by Suk et al. .
Despite the longer duration of procedure with the PLIF technique, it seems justifiable owing to the high fusion rates reported by many authors for interbody fusion ,,,,,,,,, and the overall superior reliability and resistance of the implanted systems associated with the PLIF procedures rather than PLF procedures, because of reduced mechanical stress conferred to the hardware [Figure 4], minimizing their failure as confirmed by several authors as well as this study ,,.
| Conclusion|| |
PLIF seems to be a better option for the management of isthmic spondylolisthesis on the basis of the better clinical outcome and higher fusion rates and fewer construct failures found in this study.
| Acknowledgements|| |
The funding resources were provided by the Department of Neurosurgery, Faculty of Medicine, Menoufia University.
Conflicts of interest
There are no conflicts of interest.
| References|| |
|1.||Hadra BE. The classic. Wiring of the vertebrae as a means of immobilization in fracture and Pott′s disease. Berthold E. Hadra. Med Times and Register. 1891;Vol 22, May 23, 1891. Clin Orthop Relat Res 1975; 112:4-8. |
|2.|| Albee FH. Transplantation of a portion of the tibia into spine for Pott′s disease. JAMA 1911; 57:885-887. |
|3.|| Hibbs RA. A report of 59 cases of scoliosis treated by fusion operation. By Russell A. Hibbs, 1924. Clin Orthop Relat Res 1988; 229:4-19. |
|4.|| Christensen FB. Lumbar spinal fusion. Outcome in relation to surgical methods, choice of implant and postoperative rehabilitation. Acta Orthop Scand Suppl 2004; 75:2-43. |
|5.|| Cloward RB. The treatment of ruptured lumbar intervertebral discs by vertebral body fusion. Indications, operative technique, after care. J Neurosurg 1953; 10:154-168. |
|6.|| Enker P, Steffee AD. Interbody fusion and instrumentation. Clin Orthop Relat Res 1994; 300:90-101. |
|7.|| Krishna M, Pollock RD, Bhatia C. Incidence, etiology, classification, and management of neuralgia after posterior lumbar interbody fusion surgery in 226 patients. Spine J 2008; 8:374-379. |
|8.|| Sears W. Posterior lumbar interbody fusion for degenerative spondylolisthesis: restoration of sagittal balance using insert-and-rotate interbody spacers. Spine J 2005; 5:170-179. |
|9.|| Aoki Y, Yamagata M, Ikeda Y, Nakajima F, Ohtori S, Nakagawa K, et al. A prospective randomized controlled study comparing transforaminal lumbar interbody fusion techniques for degenerative spondylolisthesis: unilateral pedicle screw and 1 cage versus bilateral pedicle screws and 2 cages. J Neurosurg Spine 2012; 17:153-159. |
|10.||1Edward Cunningham J, Elling EM, Milton AH, Robertson PA. What is the optimum fusion technique for adult isthmic spondylolisthesis - PLIF or PLF? A long-term prospective cohort comparison study. J Spinal Disord Tech 2013; 26:260-267. |
|11.||1Ekman P Moller H Tullberg T Neumann P Hedlund R. Posterior lumbar interbody fusion versus posterolateral fusion in adult isthmic spondylolisthesis. Spine (Phila Pa 1976) 2007; 32:2178-2183. |
|12.||1Hai Y, Kopacz KJ, Lee CK. Posterior lumbar interbody fusion with and without pedicle screw fixation: comparison for clinical and radiological results. Presented at the North American Spine Society; New York, NY, October 22-25, 1997 |
|13.||1Han X, Zhu Y, Cui C, Wu Y. A meta-analysis of circumferential fusion versus instrumented posterolateral fusion in the lumbar spine. Spine (Philadelphia) 2009; 34:E618-E625. |
|14.||1Kim KT, Lee SH, Lee YH, Bae SC, Suk KS Clinical outcomes of 3 fusion methods through the posterior approach in the lumbar spine. Spine (Philadelphia) 2006; 31:1351-1357. |
|15.||1Lee DY Lee SH Maeng PH. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation: a minimum 3-year follow-up study. Neurol Med Chir (Tokyo) 2010; 50:645-650. |
|16.||1Ray CD. Threaded titanium cages for lumbar interbody fusions. Spine 1997; 22:667-680. |
|17.||1Steffee A, Sitkowski D Posterior lumbar interbody fusion and plates. Clin Orthop 1988; 227:99-102. |
|18.||1Takahashi T, Hanakita J, Minami M, et al. Clinical outcomes and adverse events following transforaminal interbody fusion for lumbar degenerative spondylolisthesis in elderly patients. Neurol Med Chir (Tokyo) 2011; 51:829-835. |
|19.||1Zhou ZJ, Zhao FD, Fang XQ, Zhao X, Fan SW. Meta-analysis of instrumented posterior interbody fusion versus instrumented posterolateral fusion in the lumbar spine. J Neurosurg Spine 2011; 15:295-310. |
|20.||2Fairbank JC, Pynsent PB. The Oswestry disability index. Spine 2000; 25:2940-2952. |
|21.||2Fairbank JC, Couper J, O′Brien JP. The Oswestry Low Back Pain Disability Questionnaire. Physiotherapy 1980; 66:271-273. |
|22.||2Suk S, Lee C-K, Kim W-J, et al. Adding posterior lumbar interbody fusion to pedicle screw fixation and posterolateral fusion after decompression in spondylolytic spondylolisthesis. Spine 1997; 22:210-220. |
|23.||2Christensen BF, Laursen M, Gelineck J, Eiskjaer R SP, Thomsen K, Bunger EC. Interobserver and intraobserver agreement of radiograph interpretation with and without pedicle screw implants: the need for a detailed classification system in posterolateral spinal fusion. Spine 2001; 26:538-544. |
|24.||2Cloward RB. Spondylolisthesis: treatment by laminectomy and posterior interbody fusion. Clin Orthop Relat Res 1981; 154:74-82. |
|25.||2Lin PM. Posterior lumbar interbody fusion technique: complications and pitfalls. Clin Orthop 1985; 193:90-102. |
|26.||2Brantigan JW, Steffee AD, Lewis ML, Quinn LM, Persenaire JM. Lumbar interbody fusion using the Brantigan I/F cage for posterior lumbar interbody fusion and the variable pedicle screw placement system. Two-year results from a Food and Drug Administration investigational device exemption clinical trial. Spine 2000; 25:1437-1446. |
|27.||2Dantas FL, Prandini MN, Ferreira MA. Comparison between posterior lumbar fusion with pedicle screws and posterior lumbar interbody fusion with pedicle screws in adult spondylolisthesis. Arq Neuropsiquiatr 2007; 65:764-770. |
|28.||2La Rosa G, Conti A, Cacciola F, et al. Pedicle screw fixation for isthmic spondylolisthesis: does posterior lumbar interbody fusion improve outcome over posterolateral fusion? J Neurosurg 2003; 99: S143-S150. |
|29.||2Dehoux E Fourati E Madi K Reddy B Segal P. Posterolateral versus interbody fusion in isthmic spondylolisthesis: functional results in 52 cases with a minimum follow-up of 6 years. Acta Orthop Belg 2004; 70:578-582. |
|30.||3Musluman AM, Yilmaz A, Cansever T, et al. Posterior lumbar interbody fusion versus posterolateral fusion with instrumentation in the treatment of low-grade isthmic spondylolisthesis: midterm clinical outcomes. J Neurosurg Spine 2011; 14:488-496. |
|31.||3Madan S, Boeree NR. Outcome of posterior lumbar interbody fusion versus posterolateral fusion for spondylolytic spondylolisthesis. Spine 2002; 27:1536-1542. |
|32.||3Wu Y, Tang H, Li Z, Zhang Q, Shi Z. Outcome of posterior lumbar interbody fusion versus posterolateral fusion in lumbar degenerative disease. J Clin Neurosci 2011; 18:780-783. |
|33.||3Robert D. Interbody, posterior, and combined lumbar fusions. Spine 1995; 20:167-177. |
|34.||3Suk KS, Jeon CH, Park MS, Moon SH, Kim NH, Lee HM. Comparison between posterolateral fusion with pedicle screw fixation and anterior interbody fusion with pedicle screw fixation in adult spondylolytic spondylolisthesis. Yonsei Med J 2001; 42:316-323. |
|35.||3Oda I, Abumi K, Yu BS, Sudo H, Minami A. Types of spinal instability that require interbody support in posterior lumbar reconstruction: an in vitro biomechanical investigation. Spine 2003; 28:1573-1580. |
|36.||3La Rosa G, Cacciola F, Conti A, et al. Posterior fusion compared with posterior interbody fusion in segmental spinal fixation for adult spondylolisthesis. Neurosurg Focus 2001; 10:E9. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]