Fusion Surgery and Disc Arthroplasty

CHAPTER 30 Fusion Surgery and Disc Arthroplasty



Eugene K. Wai, Darren M. Roffey, Andrea C. Tricco, Angus Shane Don, Simon Dagenais



Description



Terminology and Subtypes


In the context of chronic low back pain (CLBP) and degenerative disc disease (DDD), fusion surgery is a broad term used to indicate various forms of lumbar surgery whose primary goal is to join bony anatomic structures in the lumbar spine that are thought to have excessive movement or otherwise contribute to presenting symptoms. Fusion surgery is also known as arthrodesis. The main types of fusion surgery are named according to the surgical approach taken (i.e., where the incision is made and the direction from which the spine is operated on) and include posterior approaches (Figure 30-1), anterior approaches, and combined anterior and posterior approaches, which are also known as circumferential or 360-degree approaches (Figure 30-2). Posterior approaches to fusion surgery include posterior lateral intertransverse fusion surgery (PLF), posterior lumbar interbody fusion surgery (PLIF), and transforaminal lumbar interbody fusion surgery (TLIF) (Figure 30-3). The main anterior approach to fusion surgery is known as anterior lumbar interbody fusion surgery (ALIF).


image

Figure 30-1 Lumbar fusion surgery: posterior approach.


(From Paz, JC. Acute care handbook for physical therapists, 3rd Edition. St. Louis, 2009, Saunders.)


image

Figure 30-2 Lumbar fusion surgery: circumferential approach.


(From Maxey L, Magnusson J. Rehabilitation for the postsurgical orthopedic patient, ed. 2. St. Louis, 2007, Mosby.)


image

Figure 30-3 Lumbar fusion surgery: transforaminal lumbar interbody approach.


(Adapted from Kim DH, Henn J, Vaccaro AR, Dickman CA (eds). Surgical Anatomy & Techniques to the Spine. Philadelphia, 2006, Saunders.)


Fusion surgery may also be categorized according to the use of surgical hardware such as plates, screws, hooks, cables, and cages, which are collectively termed instrumentation. Although surgical instrumentation was traditionally made of metal, it is now composed of a wide range of materials, such as titanium mesh, carbon fiber, and polyetheretherketone (PEEK). Noninstrumentation fusion surgery involves the use of bone grafts to fuse adjacent vertebrae. Autograft fusion surgery involves taking small bone chips from the patient’s own body such as the iliac crest, whereas allograft fusion surgery uses bone chips harvested from another person (i.e. bone bank). Autograft bone is also known as autologous or autogenous bone. Bone morphogenic protein (BMP) is a substance used to enhance the body’s natural bone growth processes and is occasionally (incorrectly) termed artificial or synthetic bone. It is also termed recombinant human bone morphogenetic protein (rhBMP).


Arthroplasty is a generic term indicating that a targeted structure is surgically removed and replaced. Disc arthroplasty describes a surgical procedure in which an intervertebral disc is removed through decompression surgery and replaced with a device intended to function as a disc replacement. Disc arthroplasty is also known as total disc replacement or artificial disc replacement. The artificial disc device normally consists of two metal plates between which a polyethylene core glides.



History and Frequency of Use


In 1891, the first spinal instrumentation procedure was performed by Hadra, who used wires to repair a spinous process fracture.1 Bone augmentation and arthrodesis for the treatment of lumbar DDD initially occurred in 1911, with successful noninstrumented fusion surgery using tibial grafts between spinal processes to stabilize the spine.2 Another technique “feathered” the lamina, decorticated the facet joints, and then added morsalized bone derived from the spinous processes, representing the first documented example of flexible stabilization utilizing autologous bone for reconstructive purposes.3 Kleinberg then pioneered the concept of using bone graft for fusion surgery in 1922.4 In 1933, the ALIF procedure was first documented by Burns.5 Internal fixation as an adjuvant to fusion surgery using bone graft was described shortly thereafter by Venable and Stuck in 1939.6 With an increased understanding of spinal fusion surgery, the PLIF procedure was developed and first performed in 1944 by Briggs and Milligan, who used bone chips collected during the laminectomy procedure in the disc space as an interbody autograft.7 In 1946, Jaslow modified the PLIF procedure by positioning an excised portion of the spinous process within the intervertebral space.8


Instrumentation advances were also occurring in the middle of the 20th century, with the original pedicle fixation procedure described in 1949.9 In 1953, Cloward described a PLIF technique that used impacted blocks of iliac crest autograft, after which the popularity of this approach increased.10 Holdsworth and Hardy were the first to report on internal fixation of the spine in patients with fracture dislocations of the thoracolumbar spine in 1953.11 The use of rigid interbody instrumentation to promote fusion surgery was originally reported in horses by DeBowes and colleagues12 and Wagner and colleagues.13 Boucher was the first to use transpedicular screws for spinal fusion surgeries in 1959.14 Harrington published his results for fusion surgery with instrumentation for scoliosis in 1962.15 Luque developed the segmental stabilization system in the late 1970s, in which two flexible L-shaped rods were wired to each of the vertebrae to correct the curve and achieve a more stable, stronger fixation.16 Bagby followed up this research using a slightly oversized, extensively perforated stainless steel cylinder (the “Bagby Basket”) filled with local bone autograft to restore the intervertebral disc space.17 Butts and colleagues furthered this concept using two parallel implants interposed between the lumbar vertebral bodies and reported achieving immediate stabilization; this technology would eventually become known as the Bagby and Kuslich (BAK) vertebral interbody cage.18


TLIF was introduced by Harms and Rolinger in 1982, enabling placement of the bone graft within the anterior or middle of the disc space to restore lumbar lordosis.19 This procedure preserved the contralateral laminae and spinous processes, making additional surface area available to help achieve a posterior fusion surgery. The first percutaneous screw placement technique was reported by Magerl in 1982 and involved the use of external fixators.20 The Cotrel-Dubousset system for spine surgery was introduced in 1984, followed by the Texas Scottish Rite system in 1991, the Moss Miami system in 1994, the Xia spine system in 1999, and the Expedium system in 2008. Although a large number of these surgical instrumentations, techniques, and devices were originally designed for scoliosis, many were later used to treat patients with DDD and CLBP. The initial discovery of rhBMP was made in 1965 by Urist and colleagues.21 Since then, at least 14 different types have been isolated and analyzed.22


Disc arthroplasty devices were first proposed in the early 1950s.23 Nachemson was the first to begin implanting a silicon testicular prosthesis into the disc space, although this procedure was later abandoned when the implants disintegrated.23 Fernstrom reported his experience with implanting a steel ball in the disc space in 1966, but this also met with poor results.23,24 Since that time, there has been a plethora of failed artificial disc designs including inelastic and elastic devices, silicon spacers, plastic spacers, silicon or plastic spacers with metal end plates, and various end plate designs including screws, pins, keels, cones, and suction caps.25,26 Various hygroscopic agents have also been used, followed by elastic beads, springs, oils, and expandable gels.25 The first such arthroplasty device approved for use in the United States was the Charite artificial disc, which was developed in the mid-1980s at the Charite University Hospital in Berlin, Germany.



Practitioner, Setting, and Availability


Fusion surgery and disc arthroplasty are usually performed by orthopedic spine surgeons or neurologic spine surgeons. In the United States, spine surgeons (orthopedic or neurologic) typically complete 4 years of undergraduate education, 4 years of medical school, and 5 to 7 years of surgical residency. Many spine surgeons also complete 1 or 2 years of optional subspecialty fellowship training to further develop clinical skills in spine surgery. Spine surgery fellowship training programs have been accredited by the Accreditation Council for Graduate Medical Education (ACGME) since 1991 and by the American College of Spine Surgery (ACSS) since 1998. After completion of residency/fellowship training, orthopedic and neurologic surgeons are eligible for board certification by the American Board of Orthopaedic Surgery (ABOS) and the American Board of Neurological Surgery (ABNS), which were founded in 1934 and 1940, respectively. Obtaining certification means the surgeon has met the specified educational, evaluation, and examination requirements of the respective board.


According to the American Academy of Orthopaedic Surgeons (AAOS), there were 17,673 orthopedic surgeons and 4605 residents practicing in the United States as of January 2010.27 Corresponding figures from the American Association of Neurological Surgeons (AANS) were 3519 neurologic surgeons and 1663 residents/fellows as of December 2009.28 The number of orthopedic and neurologic surgeons with subspecialty training in spine surgery is difficult to estimate because board certification in spine surgery is optional in the United States. The American Board of Spine Surgery (ABSS) was approved as a specialty certification board by the Medical Board of California in 2002 and reported 180 board-certified spine surgeons in the United States as of January 2010 (personal communication, Eckert M. Executive administrator, American Board of Spine Surgery, 2010).


Fusion surgery and disc arthroplasty are inpatient procedures performed in hospitals because they require general anesthesia and may require extensive postoperative care. Fusion surgery and disc arthroplasty procedures are both widely available throughout the United States.



Procedure



Preoperative


Fusion surgery and disc arthroplasty usually begin with an anesthesiologist performing a preoperative examination and history, followed by induction of general anesthesia. An endotracheal tube is inserted and the patient breathes with the assistance of a ventilator during the surgery. Preoperative intravenous antibiotics are often given to minimize the risk of postoperative infection. Depending upon the surgical approach used, patients are positioned in a prone or supine position using a flexible operating table with padding and supports. The skin in the lumbosacral region is then cleaned repeatedly using antimicrobial cleaning solutions. Sterile drapes are then placed around the area of the operation, and the surgical team wears sterile surgical attire to maintain a bacteria-free environment throughout the procedure.



General Surgical Approach


A skin incision is made by the surgeon above the area to be operated on. The length of the incision varies according to the surgical approach. The incision is then made gradually deeper by cutting through subcutaneous tissues and muscular planes, using retractors to maximize visualization (Figure 30-4). Decompression surgery is often performed before fusion surgery or disc arthroplasty to remove disc tissue and bone; that procedure is described in Chapter 29 of this text.


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Figure 30-4 Lumbar fusion surgery: complete dissection to maximize visualization of operative field.


(In Shen FH, Shaffrey C: Arthritis and arthroplasty: the spine. Philadelphia, 2010, Saunders. Adapted from Kim DH, Henn J, Vaccaro AR, Dickman CA (eds). Surgical Anatomy & Techniques to the Spine. Philadelphia, 2006, Saunders.)



Fusion Surgery


Once the intervertebral disc has been removed, fusion surgery is performed according to the particular approach selected by the surgeon. Although a detailed discussion of surgical technique is beyond the scope of this chapter, each approach will briefly be described. Noninstrumented fusion surgery requires bone chips. If these could not be obtained from the bone removed during the decompression surgery procedure, the surgeon will harvest additional bone chips from the posterior iliac crest (autograft) or obtain them from a bone bank (allograft). Bone chips will then be placed in the intervertebral disc space while applying axial distraction (ALIF, TLIF, or FLIF), or along the transverse processes (PLF). BMP may also be used with, or instead of, bone chips, depending on availability and the surgeon’s preference. Instrumented fusion surgery may use a variety of devices to fix adjacent vertebrae, such as metal rods held in place by screws placed through the pedicles and drilled into the vertebral bodies. Intervertebral body cages may also be placed in the intervertebral disc space while applying axial distraction; serrated edges on the cages help keep them in place, as does gravity using the weight of the upper body.



Disc Arthroplasty


To perform disc arthroplasty, a standard anterior approach to the lumbar discs is used, with the patient lying in a supine position (Figure 30-5). After the intervertebral disc has been removed, the artificial disc device will be placed in the intervertebral disc space while held under axial distraction. Positioning of the device should be verified extensively using fluoroscopic guidance in an attempt to preserve alignment with adjacent vertebral bodies and maximize lumbosacral motion. The device remains fixed to the adjacent end plates with small keels.


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Figure 30-5 Lumbar fusion surgery: standard anterior approach retracting major vessels to expose intervertebral disc.


(Modified from Yue JJ, Bertagnoli R, McAfee PC, An HS. Motion preservation surgery of the spine. Philadelphia, 2008, Saunders.)



Regulatory Status


Equipment and instruments used during fusion surgery or disc arthroplasty are regulated by the US Food and Drug Administration (FDA) as class I or class II medical devices. Class I medical devices present a negligible potential for harm and are subject only to general controls which provide reasonable assurance of the safety and effectiveness of the device. Surgical devices in this category include rongeurs (bone pliers), rotary burrs (bone drill bits), retractors, and other nonpowered hand-held surgical instruments. Class II medical devices are subjected to general controls and additional special controls to provide reasonable assurance that they will perform as indicated and will not cause harm or injury to the patient and/or surgeon. Obtaining approval to market a class II medical device requires a 510(k) premarket submission to the FDA with evidence from the manufacturer that the new device is substantially equivalent to a currently approved and legally marketed similar device. Devices in this category include surgical drapes, suture materials, electrically powered arthroscopes, and digital fluoroscopic equipment.


Many of the developmental trends in spine surgery over the past 20 years have been driven by the challenge of achieving arthrodesis in the lumbar spine. Because of this, the FDA has seen a dramatic increase in the number of applications for bone graft substitutes and disc arthroplasty technologies. Currently, there are two genetically engineered rhBMP bone graft substitutes available in the United States. In 2002, rhBMP-2 (Infuse Bone Graft, Medtronic) was approved by the FDA for use in ALIF cage (LT-Cage, Medtronic) procedures, with results subsequently indicating fusion surgery rates superior to those associated with autograft.29 In 2006, rhBMP-7 (Osteogenic Protein-1 [OP-1] Putty, Stryker) was approved by the FDA for revision posterolateral (intertransverse) lumbar spinal fusion surgery.30


Currently, there are four intervertebral disc arthroplasty devices available in the United States: Charité (Depuy) (Figure 30-6), ProDisc-L (Synthes) (Figure 30-7), Maverick (Medtronic), and Flexicore (Stryker). The Charité and ProDisc-L received FDA approval in 2004 and 2006 respectively, while Maverick and Flexicore multicenter trials have completed enrollment in their RCTs and are currently operating in continued access, nonrandomized modes. SpinalMotion (Mountain View, California), developer of the Kineflex lumbar artificial disc implant, submitted their premarketing approval application to the FDA in 2009. One of the potential barriers to using any of the disc arthroplasty devices instead of traditional fusion surgery for CLBP with advanced DDD is lack of end plate structural integrity (Figure 30-8).


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Figure 30-6 Total disc arthroplasty device: Charité (Depuy).


(From Yue JJ, Bertagnoli R, McAfee PC, An HS. Motion preservation surgery of the spine. Philadelphia, 2008, Saunders.)


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Figure 30-7 Total disc arthroplasty device: ProDisc-L (Synthes).


(© Synthes, Inc. or its affiliates. All rights reserved.)


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Figure 30-8 Lack of end plate structural integrity may represent a contraindication to total disc arthroplasty.


(From Yue JJ, Bertagnoli R, McAfee PC, An HS. Motion preservation surgery of the spine. Philadelphia, 2008, Saunders.)



Theory



Mechanism of Action



Fusion Surgery


Kirkaldy-Willis and colleagues described a degenerative cascade involving the intervertebral discs, facet joints, and ligamentum flavum that could eventually lead to neural impingement if sufficiently severe.31 This degenerative cascade initially involves dehydration of the disc and loss of disc height that naturally occurs with aging. These changes in disc composition and morphology may lead to posterior bulging, which exerts pressure on the ligamentum flavum and pushes it toward the neural canal. Further degeneration or injury to a degenerated disc may then lead to tears in the annulus, resulting in posterior prolapse of the nucleus pulposus into the neural canal.


Degenerative changes in the disc may affect the biomechanical properties of the motion segment, leading to mild instability that increases the mechanical load on surrounding structures. In response to this increased load, the facet joints may undergo degenerative changes including growth of osteophytes as well as facet joint capsule and ligament hypertrophy, which may eventually grow into the neural canal. Continued degeneration of the facet joints may eventually lead to segmental instability and contribute to degenerative spondylolisthesis or lateral listhesis, resulting in narrowing of the neural canal or intervertebral foramen, leading to further impingement of the neural structures.


Impingement of the neural canal may result in neurologic dysfunction from direct or indirect causes. Spinal nerve root function may be disrupted due to direct mechanical compression, although the amount of pressure required to do this remains a matter of continued research. An alternative mechanism that has been proposed is that spinal nerve root function may be indirectly affected by chemical mediators of the acute inflammatory cascade (e.g., cytokines).32 Claudication may result from direct mechanical compression of spinal nerve roots or from focal ischemia.33


Whereas decompression surgery may alleviate neurologic dysfunction by removing one or more of the structures with degenerative changes that may be causing or contributing to impingement of the neural canal, decompression alone may not be sufficient to address an underlying etiology related to severe degeneration. Because the elimination of motion after solid arthrodesis has been effective for pain relief in other arthritic joints within the body (e.g., ankle, wrist, hip), it is no surprise that fusion surgery to eliminate excessive motion leading to segmental instability has been used to treat CLBP. However, it should be acknowledged that the precise mechanism of action by which fusion surgery may alleviate symptoms of CLBP is not completely understood. The complexity of the multiple spinal articulations and uncertainty in determining whether these joints are in fact related to the etiology of CLBP underlines the inherent challenge presented by fusion surgery when compared to arthrodesis in smaller joints with less complex movement. Some authors have previously reported that clinical outcomes obtained following fusion surgery did not correlate with the presence of a radiographically solid arthrodesis.34–36



Disc Arthroplasty


The premise for disc arthroplasty stems from the assumption that CLBP is due to an abnormal and painful spinal motion segment, and that the artificial disc would function as a painless and physiologic replacement for the degenerated disc. This premise is buoyed by the success in treating arthritic hips and knees with arthroplasty, where replacements are now expected to last 15 to 20 years in an elderly population with generally favorable outcomes. Proponents of disc arthroplasty often argue that this approach is superior to the unsatisfactory results observed with fusion surgery because it avoids the morbidity associated with pseudarthrosis, prolonged healing required for fusion surgery, bone graft donor site pain, increased adjacent segment strain, and risk of accelerated DDD. Disc arthroplasty purports to reproduce the natural load transmission properties of the intervertebral disc and maintain spinal motion segment characteristics, theoretically avoiding some of the above problems related to fusion surgery and the associated adjacent level strain this may cause. It should be acknowledged that these assertions have not been conclusively demonstrated and may represent an oversimplification of a complex phenomenon.



Indication



Fusion Surgery


Fusion surgery is often used for a variety of indications. Given its primary objective, fusion surgery is most commonly used for CLBP with persistent, severe symptoms that may be due to underlying surgical instability secondary to degenerative spondylolisthesis, DDD, isthmic spondylolisthesis, spondylolysis, or failed back surgery syndrome. However, defining patients with CLBP who may be appropriate candidates for fusion surgery remains challenging because findings from the physical and neurologic examination, as well as advanced imaging or other diagnostic testing, have generally failed to identify a clear pathoanatomic cause for CLBP. This lack of consensus regarding appropriate indications has led to large geographic variations in the rate of lumbar spine surgery across the United States that cannot be explained by demographics alone.37 This uncertainty may perhaps best be illustrated by contrasting the two main schools of thought with respect to CLBP in the absence of serious spinal pathology, which are briefly discussed here.



Pain Generator Approach


The pain generator approach to CLBP generally focuses on attempting to identify a specific anatomic structure that is the root “pain generator” responsible for the symptoms observed in patients with CLBP. Following this approach requires several assumptions. First, this approach assumes that a specific pathoanatomic cause exists for CLBP, independently of any psychological, social, economical, neurophysiologic, or other contributing factors. Second, this approach assumes that one or more diagnostic tests are able to identify that specific pathoanatomic cause with certainty. Third, this approach assumes that one or more interventions may be recommended based on the underlying pathoanatomic cause. In an ideal world, this approach would be expected to be highly effective in eliminating symptoms of CLBP after instituting appropriate interventions aimed at correcting abnormal findings identified through diagnostic testing.



Biopsychosocial Approach


The biopsychosocial approach to CLBP is founded on findings from many epidemiologic, scientific, and clinical studies, which generally suggest that no specific pathoanatomic cause or structure can be identified to explain symptoms of CLBP in the vast majority of patients. This approach acknowledges the consistently poor long-term outcomes reported in many clinical trials of interventions directed at specific anatomic structures thought to contribute to CLBP. This approach also acknowledges that although subgroups with specific, correctable pathology may exist in the large number of patients with CLBP, the ability to identify those subgroups and institute interventions to improve their long-term prognosis is generally limited. The biopsychosocial approach accepts that pathoanatomic findings alone cannot fully explain the clinical course of CLBP, and other factors must be involved in its genesis, chronicity, and prognosis. Although these other factors are not completely understood, they likely include psychological, social, economic, occupational, and behavioral factors influencing a person’s response to experiencing CLBP. Rather than targeting interventions at specific pathoanatomic structures, this approach is generally aimed at restoring normal physical and mental function through education, behavioral therapy, activity modification, and multidisciplinary physical rehabilitation.



Combined Approach


The combined approach to CLBP attempts to integrate the best elements of both approaches described above. For fusion surgery, this combined approach would first attempt to identify patients with CLBP in whom there is a high degree of certainty that instability may be responsible for their symptoms and offer them a surgical intervention. For other patients where the likelihood of long-term benefit from fusion surgery is uncertain, the combined approach would likely promote the use of multidisciplinary rehabilitation combining educational, behavioral, and exercise approaches (described elsewhere in this text) rather than recommend fusion surgery. An important consideration in this combined approach is the timing of any proposed surgical intervention. Generally, fusion surgery should not be considered for CLBP unless the patient has suffered substantial functional disability and unremitting pain for a prolonged period despite receiving appropriate conservative interventions. Although the specific definition of appropriate conservative interventions remains elusive and depends on the clinical scenario, it may be appropriate to at least consider fusion surgery for severe CLBP of more than 6 months duration if no clinically meaningful improvement is noted following a coordinated approach with analgesics, supervised therapeutic exercise, manual therapy, education, and behavioral therapy.38



Disc Arthroplasty


The indications for disc arthroplasty are generally the same as those described above for fusion surgery. Because the goal of disc arthroplasty is to preserve some degree of motion at the targeted vertebral segment, this approach is generally recommended for younger patients with CLBP in whom preserving the maximal possible range of motion while restoring stability is desired. Because disc arthroplasty is predicated on preserving normal motion in the lumbosacral region, it is generally indicated in patients with CLBP who are thought to have degenerative or other changes that are isolated to one particular motion segment rather than widespread DDD. Those patients are thought to benefit the most from a motion preserving approach, while those with broader, multilevel degenerative changes may not be appropriate candidates for disc arthroplasty.



Assessment


Before receiving fusion surgery or disc arthroplasty, patients should first be assessed for LBP using an evidence-based and goal-oriented approach focused on the patient history and neurologic examination, as discussed in Chapter 3. Clinicians should also inquire about medication history to note prior hypersensitivity/allergy or adverse events (AEs) with drugs similar to those being considered, and evaluate contraindications for these types of drugs. Advanced imaging such as magnetic resonance imaging (MRI), computed tomography (CT), or CT myelography is required to help guide the spine specialist to target the appropriate spinal levels involved in a patient’s CLBP and related neurologic dysfunction. Findings on advanced imaging that may be of particular interest when considering fusion surgery include advanced degenerative changes. However, the presence of these findings on advanced imaging is not sufficient to justify proceeding with spinal surgery. It is of the utmost importance that any findings on advanced imaging be correlated with findings made independently from the medical history, symptoms, physical examination, and neurologic examination. Screening for biopsychosocial risk factors associated with poor outcomes should also be conducted before considering fusion surgery or disc arthroplasty.



Efficacy


Evidence supporting the efficacy of these interventions for CLBP was summarized from recent clinical practice guidelines (CPGs), systematic reviews (SRs), and randomized controlled trials (RCTs).



Clinical Practice Guidelines



Fusion Surgery


Five of the recent national CPGs on the management of CLBP have assessed and summarized the evidence to make specific recommendations about the efficacy of fusion surgery.


The CPG from Belgium in 2006 found low-quality evidence against fusion surgery for LBP without neurologic involvement.39


The CPG from Europe in 2004 could not recommend fusion surgery for CLBP because multidisciplinary rehabilitation was shown to be as effective as fusion surgery. However, fusion surgery could be used if all other conservative treatments were unsuccessful and combined behavioral and exercise interventions are not available in the patient’s geographic area.40


Similarly, the CPG from Italy in 2007 only recommended fusion surgery if 2 years of all other conservative therapy failed and psychological prognostic factors were absent.41


The CPG from the United Kingdom in 2009 recommended fusion surgery only if the patient was in severe enough pain to consider surgery an option and all other treatments had failed including combined physical and psychological interventions.42


The CPG from the United States in 2009 found fair evidence of a moderate net benefit for fusion surgery versus standard nonsurgical therapy and fair evidence of no benefit versus intensive rehabilitation for managing CLBP without neurologic involvement.43



Disc Arthroplasty


One of the recent national CPGs on the management of CLBP has assessed and summarized the evidence to make specific recommendations about the efficacy of disc arthroplasty.


For DDD without neurologic involvement, the CPG from the United States in 2009 found fair evidence of no difference for disc arthroplasty versus fusion surgery for up to 2 years of follow-up and insufficient evidence for longer-term outcomes.43


Findings from the above CPGs are summarized in Table 30-1.


TABLE 30-1 Clinical Practice Guideline Recommendations of Fusion Surgery and Disc Arthroplasty for Chronic Low Back Pain



































Reference Country Conclusion
Fusion Surgery
39 Belgium Not recommended
40 Europe Not recommended
41 Italy Recommended
42 United Kingdom Recommended
43 United States Recommended
Disc Arthroplasty
43 United States Insufficient evidence


Systematic Reviews



Fusion Surgery



Cochrane Collaboration


The Cochrane Collaboration conducted an SR in 2005 on various forms of lumbar surgery for degenerative lumbar spondylosis.45 A total of 31 RCTs were identified, of which 19 examined the effects of fusion surgery. Of the 19 RCTs identified for fusion surgery, 4 examined CLBP, 2 examined chronic DDD, 3 examined DDD without specifying the duration of symptoms, 5 examined spondylolisthesis, 2 included a mixture of spondylolisthesis and spinal stenosis, 1 included spinal stenosis, 1 included a mixture of failed back surgery syndrome, DDD, degenerative spondylolisthesis, and isthmic spondylolisthesis, and 1 included a mixture of patients without specifying the duration of LBP or condition.35,45–61


Three RCTs examined decompression surgery alone versus decompression surgery combined with fusion surgery, and their pooled results via meta-analysis did not find any statistically significant differences between the two approaches.34,58,59 In addition, another RCT did not find any differences between fusion surgery alone versus fusion surgery combined with decompression surgery for patients with isthmic spondylolisthesis.57 One RCT observed a statistically significant improvement in pain and disability for fusion surgery versus an intensive exercise program after 2 years of follow-up for patients with isthmic spondylolisthesis.54 One RCT randomized patients to three different forms of fusion surgery or to physical therapy and observed statistically significant improvements in pain and disability after 2 years of follow-up among the groups who received fusion surgery.46 Another RCT examined the effects of fusion surgery versus a multidisciplinary rehabilitation program (including a cognitive behavioral component) and observed no statistically significant differences in pain and function.46 Two RCTs compared fusion surgery versus disc arthroplasty and observed no statistically significant differences at the end of follow-up.49,50 Eight RCTs were pooled via meta-analysis to show that fusion surgery with instrumentation improved the radiologic fusion surgery rate, while four RCTs provided inconsistent evidence about the relative superiority of different techniques for fusion surgery (i.e., anterior, posterior, circumferential).

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Jun 14, 2016 | Posted by in PAIN MEDICINE | Comments Off on Fusion Surgery and Disc Arthroplasty

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