Instituto de Patologia da Coluna, Minimally Invasive Surgery, Sao Paulo/SP, Brazil

Transcription

1 WScJ 3: , 2010 Standalone Anterior Interbody Fusion Procedure for the Treatment of Low-Grade Spondylolisthesis: A Case Series Leonardo Oliveira 1,2, Luis Marchi 1, Etevaldo Coutinho 1, Luiz Pimenta 1,3 1 Instituto de Patologia da Coluna, Minimally Invasive Surgery, Sao Paulo/SP, Brazil 2 Department of Radiology, Universidade Federal de Sao Paulo, Sao Paulo/SP, Brazil 3 Department of Neurosurgery, University of California San Diego, San Diego/CA, USA ABSTRACT OBJECTIVE: Spondylolisthesis may cause local instability, facet distraction, and central and foraminal stenosis. A common surgical aproach is to reduce and to stabilize the olisthesis posteriorly with pedicle screws and rods. In this work we propose an anterior one-stage approach for the treatment of spondylolisthesis, without direct decompression of neural structures nor posterior supplementation. AIM: This article reports an innovative way to reduce and stabilize low grade isthmic or degenerative lumbar spondylolisthesis by a minimal invasive anterior approach in a standalone construction. MATERIALS and METHOD: Eight patients and nine lumbar levels were treated through the mini-alif procedure. It was used an unique interbody cage, which has screws and a hollowed screw that pass through the device and reach at the upper lower vertebral body. Radiological and clinical data were collected at pre, intra and postoperative (one and six weeks, three, six and twelve months) follow-up visits. RESULTS: The average surgical time was 108 minutes and no intraoperative complications occurred. One postoperative complication was observed: post-surgical seroma, which was solved after intervention. Successful clinical results were testified in VAS an ODI scores. VAS and ODI scores decreased at postoperative visits. We can say that in all cases were achieved the surgical objectives: disc height gain, olisthesis correction, spine level stabilization, axial and/or radicular pain reduction. CONCLUSION: Low grade spondylolistesis was treated using stand alone anterior interbody fusion device without posterior decompression and supplementation. Good clinical and radiological results were achieved, providing the efficacy of the procedure in the treatment of different spondylolisthesis etiologies. KEY WORDS: ALIF, Arthrodesis, Lumbar, Spine, Spondylolisthesis INTRODUCTION Lumbar spondylolisthesis is often identified on clinical evaluations of patients with low back pain (5). It is defined as the forward slippage of one vertebra on its lower and has been classified into five major types based on both etiological and anatomical factors (15). The most common etiologies are degenerative and isthmic spondylolisthesis. The degeneration of the facet joints and intervertebral disc, and spondylolysis are responsible for the emergence of these respective pathologies (5). Although these two disease groups have a different pathogenesis, they represent unstable conditions of spine, and the treatment principles are the same. A good fusion is mandatory for good outcomes in isthmic and degenerative spondylolisthesis (8, 10). 194 World Spinal Column Journal, Volume 1 / No: 3 / September 2010

2 L Oliveira et al. The surgical goals in spondylolisthesis include stabilization of the affected level, decompression of neural elements, and restoration of the disc height and sagittal plane alignment. The stabilization is accomplished by arthrodesis from a posterior, anterior, or combined approach (7,11). The reconstruction of the anterior column is extremely important because 80% of the compressive, torsion, and shear forces are transmitted over the anterior column (4,15,16), and an interbody fusion enhances the opportunity for arthrodesis, generating biomechanical stabilization of the spinal segment (5,12, 13). Minimally invasive anterior lumbar interbody fusion (mini-alif) is one of the surgical options for the treatment of spondylolisthesis, indirect decompressing the neural structures, overcoming the technical limitations of the different posterior approaches and providing segmental stabilization of the affected level (6, 9). In this present study, we propose a new one-stage option using an interbody fusion device by mini-alif without the need of posterior decompression and supplementation for the treatment of low-grade spondylolisthesis. METHODS It is prospective non-randomized single-center evaluation of patients with low grade lumbar spondylolisthesis treated by standalone mini-alif. Clinical and radiographic data were analyzed to access safe and effectiveness of the proposed treatment. There were eight enrolled patients from August 2009 through April Inclusion criteria were low grade (I or II) lumbar spondylolistesis (degenerative or isthmic) on L5S1 and/or L4L5, central and foraminal clinical relevant stenosis, and at least 6 months of conservative care. Exclusion criteria were without previous surgical intervention (fusion or decompression) at the affected or adjacent spine levels, autoimmune disease, malignancy and pregnancy. Radiographic evaluation included x-ray, magnetic resonance (MRI) and computed tomography (CT) images. Olisthesis values were represented by the percentage of slippage one vertebra over the lower one. Values from 0 to 25% were considered to represent a grade I spondylolisthesis, while values from 25% to 50% were classified as grade II. Clinical self reported outcomes were assessed on Visual Analogue Scale (VAS) and Oswestry Disability World Spinal Column Journal, Volume 1 / No: 3 / September 2010 Index (ODI) questionnaires. Follow-up included preoperative and postoperative visits, on one and six weeks, three, six and 12 months. Seven cases were single level treated (L5S1) and one case was double level treated (L4L5 and L5S1). The surgeries were performed through a mini-alif using a retroperitoneal approach, without any posterior supplementation. Disc exposure was followed by ALL removal, partial discectomy, endplate preparation, disc space distraction and interbody device insertion, two screws (proximal) and one screw cage (distal) threading. The interbody cage was filled with silicate substituted synthetic calcium phosphate bone graft (Actifuse ABX, Baxter International Inc.). The interbody device Fusimax Cage on Cage (MDT, São Paulo, Brazil; Figure 1) is a titanium lordotic cage with two screws directed to the upper vertebra and a caudal directed hollow screw, which may act as another cage. So the primary fusion is either performed by anatomical pressures over the device and by the screws fixation, while the secondary fusion could be achieved by bone growth athwart both intravertebral and interbody cages. Statistical analyzes were performed through t-student tests considering 95% confidence intervals. RESULTS Five males and three females were enrolled. The case series was characterized by a mean age of 43.4 years old and 28.4 average BMI. Discectomy and interbody cage placement were performed on eight L5S1 levels and on one L4L5 levels. Mean surgical time was 108 minutes with 100cc average blood loss. At the point this article the mean follow-up is eight months (3 12, range). No intraoperative complication occurred. Average hospital discharge was 30 hours. One access related complication occurred (12.5%), a patient evolved with abdominal seroma and solved after intervention. No other complication occurred. Using a quantitative method for olisthesis assessment, preoperative x-rays evidenced that the studied patient group had 24% of mean slippage. X-ray analysis showed that the procedure achieved 50% correction (Figure 2). During the follow-up visits no significant subsidence or radiolucency has occurred. 195

3 Standalone Anterior Interbody Fusion Procedure for the Treatment of Low-Grade Spondylolisthesis: A Case Series Figure 1: The Fusimax Cage on Cage device (MDT, Rio Claro, Sao Paulo, Brazil) in different views. A) superior view. B) lateral view. C) anterior view. D) posterior view. E) inferior angled view. F) positioned in the L5S1 disc space. Note two cranial directed screws and one caudal directed hollow screw. Figure 2: Olisthesis improvement. It is shown olisthesis average values (± standard deviation) pre and postoperatively (one week follow-up point). Values represent percentage of slippage assessed on lateral x-rays images. p=0,001. Through the outcome assessment in Visual Analogue Scale (Figure 3), we could observe consistent reduce in back pain and legs pain, data that statistically testify the value of individual radiological data and clinical reports. Also, ODI questionnaire scores testified clinical patient improvement (Figure 4). CASE EXAMPLES Case #1 H.J.C., male, 42 years old, back and leg pain for 2 years, worsening during the last year, unresponsive to conservative care. Spondylolisthesis L5S1 grade I (Figure Figure 3: Visual Analogue Scale (VAS) outcomes assessment. Mean values for back and leg questionnaires are ploted in the graphic. All postop mean values are statistically different from preop scores (p<0.05). Figure 4: Oswestry Disability Index (ODI) outcomes assessment. From 6 weeks to 6 months, mean values are statistically different from preop scores (p<0.05). 196 World Spinal Column Journal, Volume 1 / No: 3 / September 2010

4 L Oliveira et al. 5). Preoperative VAS back and leg score, 95. Soon after surgery, radicular pain was totally solved and back pain was consistently reduced. It was possible to observe in the preop MRI that the L5S1 intervertebral disc was dehydrated and posterior located to the L5 vertebrae (Figure 5). Posterior L5S1 intervertebral space was diminished, foraminal spaces were narrowed by L5 pedicle and by the disc. Postoperative X-Rays show spondylolistesis reduction, disc height augmentation and foraminal spaces widening (Figure 6). A good spine primary fusion result was achieved and can be observed in the dynamic X-Rays. Case #2 E.I., male, 41 years old, with axial back pain for 20 years. During past two years feels irradiated bilateral pain, can t stand. Degenerative Disc Disease (DDD) L4L5, spondylolistesis L5S1 grade I, collapsed L5S1 disc and L5 pars fracture (Figure 7). Preoperative VAS back and both leg, 100. Pain reduced 70% one week after surgery. In preoperative MRIs it was possible to verify bilateral stenosis with no central stenosis (Figure 7). Surgery achieved wide intervertebral space gain, which allowed L5 pedicle rise and foramen opening (Figure 8). Case #3 E.G.S.N., male, 53 years old, axial and radicular pain for the past one year, not respondent to conservative care. Retrolistesis L4L5, listhesis L5S1 and L4L5 facet luxation. L5 pars fracture (Figure 9). Preoperative VAS back = 100, VAS legs = 80. Both affected lumbar levels were anteriorly approached and received the Cage on Cage interbody prosthesis. Soon after surgery patient referred 75% reduction in legs pain and 60% in back pain. The prosteshes were well aligned and disc height gain was achieved as expected (Figure 9). DISCUSSION In the present article we report cases of low-grade spondylolistesis treated by minimally invasive anterior lumbar interbody fusion. The procedure did not included any posterior access, what may avoid posterior access related risks: neural damage or epidural scar as a result of avoiding contact with the thecal sac, back muscle injury and significant blood loss. Clinical emerging signs were substantially reduced after surgery and radiological assessments testified that the surgical objectives were reached and maintained in a medium term follow-up. There are several surgical options for the treatment of spondylolisthesis (3). Choice is influenced by many technical factors, including anatomic variation of patient and surgeon s experience. Although the best surgical technique has not yet been determined, most surgeons have thought that posterior decompression, the so-called Figure 5: Case #1 preoperative exams. On the top are shown MRI slices, one axial and 4 saggittal images. In the axial one is revealed the bottom L5 endplate. In the bottom exams there are dynamic X-Rays. World Spinal Column Journal, Volume 1 / No: 3 / September

5 Standalone Anterior Interbody Fusion Procedure for the Treatment of Low-Grade Spondylolisthesis: A Case Series Figure 6: Case #1 postoperative X-Rays. Here are shown orthostatic lateral images in diverse postoperative time, also antero-posterior and dynamic images in 3 months follow-up visit. Figure 8: Case #2 postoperative X-Rays. Here are shown orthostatic lateral images in diverse postoperative time, also antero-posterior and dynamic images in 6 week follow-up visit. Figure 7: Case #2 preoperative exams. On the top are shown MRI saggittal slices, within central and left and right lateral slices. Dynamic X-Rays are at the bottom images. Figure 9: Case #3 exams. On the top are shown preoperative images and in the bottom, 3 months follow-up X-rays. 198 World Spinal Column Journal, Volume 1 / No: 3 / September 2010

6 L Oliveira et al. Gill operation, is necessary for isthmic spondylolisthesis (15). However, the Gill procedure can often lead to spinal instability and deformity (16). To prevent the defects of posterior laminectomy, posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) were developed (17, 18). But for cases presenting degenerative disc disease require wide dissection of normal tissue and excessive neural retraction, excessive blood loss, increased postoperative pain and recovery time. Most posterior approaches cannot avoid the risk of neural damage. Isthmic and degenerative are completely different entities in pathoanatomy and symptoms as well regarding indication for stabilization (19). Usually low grade isthmic does not need surgery (20), but we restricted it only for clinically and radiological relevant cases. With disc height diminishing and slipped vertebrae, the foramens usually are stenosed by the disc and the pedicle (21). With the disc removal and interbody spacer insertion, it was possible to provide disc height gain and slippage correction. These changes may remove the damaged disc, possible pain generator; opening the foraminal spaces, decompressing the neural roots; stabilize treated spine levels, preventing abnormal movements to overstress facets, muscles and adjacent levels elements. Moreover, for one-stage anterior lumbar fusion procedures it may be important to use a device with supplemental elements that increases primary fixation, prevents postoperative device misalignment and ensures the correction achieved on surgery. Unfortunatelly, the cage material, titanium, does not allow us to access secondary fusion (bone ingrowth) on CT images. But through x-rays it is possible to measure range of motion (ROM), and accompanied to absent radiolucency signs on CT it is possible to access primary fusion success. In this study, the one stage surgery provided the advantages of a minimally invasive surgical technique and reduced hospital stay. In conclusion, we demonstrate that the mini-alif technique without posterior decompression is a safe and effective technique for the treatment of lowgrade spondylolisthesis with leg pain. Future plans include to compare anterior interbody fusion versus posterior stabilization in a prospective randomized multicenter study for the treatment of lowgrade spondylolistesis. World Spinal Column Journal, Volume 1 / No: 3 / September 2010 CONCLUSION It was possible to treat isthmic or degenerative spondylolistesis with anterior interbody fusion without direct decompression nor posterior reduction and stabilization. To this point the procedure seems to be safe, radiological efficient and clinically effective, and other clinical studies are necessary to address the surgical feasibility of this procedure for this and other indications. BIBLIOGRAPHY 1. Evans JH (1985) Biomechanics of lumbar fusion. Clin Orthop 193: Harms J (1992) Screw-threaded rod system in spinal fusion surgery. Spine 6: Harry N. Herkowitz. Degenerative lumbar spondylolisthesis: evolution of surgical management. Spine J Jul;9(7): Ishihara H, Osada R, Kanamori M et al (2001) Minimum 10-year follow up study of anterior lumbar interbody fusion for isthmic spondylolisthesis. J Spinal Disord 14: Kalichman L, Kim DH, Li L, Guermazi A, Berkin V, Hunter DJ. Spondylolysis and spondylolisthesis: prevalence and association with low back pain in the adult community-based population. Spine Jan 15;34(2): Lee SH, Choi WG, Lim SR, Kang HY, Shin SW. Minimally invasive anterior lumbar interbody fusion followed by percutaneous pedicle screw fixation for isthmic spondylolisthesis. Spine J Nov- Dec;4(6): Lin PM (1977) A technical modification of Cloward s posterior lumbar interbody fusion. Neurosurgery 1: Martin CR, Gruszczynski AT, Braunsfurth HA, Fallatah SM, O Neil J, Wai EK. The surgical management of degenerative lumbar spondylolisthesis: a systematic review. Spine. 2007;32: Mayer HM. A new microsurgical technique for minimally invasive anterior lumbar interbody fusion. Spine 1997;22: Sengupta DK, Herkowitz HN. Degenerative spondylolisthesis: review of current trends and controversies. Spine. 2005;30:S71 S Spruit M, Pavlov PW, Leitao J et al (2002) Posterior reduction and anterior lumbar interbody fusion in symptomatic low-grade adult isthmic spondylolisthesis: short-term radiological and functional outcome. Eur Spine 11: Steffee AD, Sitkowski DJ (1988) Posterior lumbar interbody fusion and plates. Clin Orthop 227: Voor MJ, Mehta S, Wang M et al (1998) Biomechanical evaluation of posterior and anterior lumbar interbody fusion techniques. J Spinal Dis 11: Gill G., J. Manning and H. White, Surgical treatment of spondylolisthesis without spine fusion, J Bone Joint Surg Am 37 (1955), pp

7 Standalone Anterior Interbody Fusion Procedure for the Treatment of Low-Grade Spondylolisthesis: A Case Series 16. Papagelopoulos P.J., H.A. Peterson and M.J. Ebersold et al., Spinal column deformity and instability after lumbar or thoracolumbar laminectomy for intraspinal tumors in children and young adults, Spine 22 (1997), pp Cloward, R. The treatment of ruptured intervertebral discs by vertebral body fusion. Indications, operation technique after care, J Neurosurg 10 (1953), pp Okuyama K., Abe E.and Suzuki T. Posterior lumbar interbody fusion: a retrospective study of complications after facet joint excision and pedicle screw fixation in 148 cases, Acta Orthop Scand 70 (1999), pp Yang SW, Langrana NA, Lee CK (1986) Biomechanics of lumbosacral spinal fusion in combined compression-torsion loads. Spine 11: Wiltse LL, Newman PH, Macnab I. Classification of spondylolisis and spondylolisthesis. Clin Orthop 1976;117: Weinstein JN, Tosteson TD, Lurie JD, Tosteson AN, Blood E, Hanscom B, Herkowitz H, Cammisa F, Albert T, Boden SD, Hilibrand A, Goldberg H, Berven S, An H. Surgical versus nonsurgical therapy for lumbar spinal stenosis. N Engl J Med Feb 21;358(8): Manuscript submitted May 14, Accepted July 16, 2010 Address correspondence to: Leonardo Oliveira, Instituto de Patologia da Coluna, Minimally Invasive Surgery, Sao Paulo / SP, Brazil leonardo@luizpimenta.com.br 200 World Spinal Column Journal, Volume 1 / No: 3 / September 2010