Spinal Disorders: Fundamentals of Diagnosis and Treatment Part 76 doc

Nerve Root Block A nerve root block can be helpful in deciding equivocal cases of neural compres- sion and radiculopathy (seeChapter 10 ). Particularly in degenerative spondylo- listhesis, anerve root block can be also used to support non-operative treatment. Functional Myelography CT myelography has been surpassed by MRI for the vast majority of indications. However, it is helpful in cases with: contraindications for MRI (e.g. pacemaker) functional stenosis postoperative (iatrogenic) spondylolisthesis Particularly in postoperative spondylolisthesis, myelography and postmyelo-CT are valuable Myelography alone is of limited use. Because a complete block of contrast fluid is occasionallyfound,thedegreeofpathology,especiallyofnerverootcompres- sion, is not adequately visualized. Without doubt there is the advantage of envis- aging the implications of lumbar flexion/extension for the spinal canal ( Fig. 5), yet in our opinion the invasive method only has true value if a consecutive CT myelography is performed. In cases where a postoperative spondylolisthesis is suspected (Wiltse Type IV), we routinely perform myelography and myelo-CT. This enables us to determine the degree of instability as well as the amount of postoperative scarring, which is important for planning surgery. a b Figure 5. Functional myelography a, b Functional myelography of an unstable spondylolisthesis demonstrating a narrowing of the spinal canal in extension at the level of L4/5 compared to flexion. 744 Section Spinal Deformities and Malformations Non-operative Treatment In the management of spondylolisthesis, the spine specialist needs to take into account various important aspects which will crucially influence the treatment decision and modality ( Table 3): Table 3. Factors influencing treatment natural history neurologic deficit grade of slippage severity of complaints lumbosacral anatomy duration of symptoms age comorbidities Natural History Low-grade spondylolisthesis in adults is usually a benign condition with little progression Some spondylolistheses progress to severe deformities yet are associated with no or only mild pain and no neurologic deficit and are uncovered only incidentally. Other slips progress very little but produce significant symptoms [30]. While nat- ural history is benign in low-grade adult spondylolisthesis, there is a high ten- dency for slip progression in children. High-grade slips almost always necessitate surgical treatment; yet low-grade slips can be managed non-operatively in the majority of cases. The risk of slip progression is very high in the presence of a A rounded sacral dome pre- disposes to slip progression lumbosacral deformity and a rounded sacrum dome, which often leads to a high- grade slip and a lumbosacral kyphotic deformity. In adults with low-grade spon- dylolytic, degenerative or postsurgical spondylolisthesis (Meyerding I and II), the natural history of the condition is usually benign [4, 24]. While progressive deformity might well occur due to increase in degeneration at the slipped seg- ment, the incidence and magnitude of such progression is small [44]. Often, independently of slippage, back pain improves when the disc space has completely collapsed. In only 30% of these cases does slippage progress, and about 75% of the patients who are initially neurologically intact do not deterio- rate over time [58]. These are the patients who will respond to a conservative treatment. Conversely, most patients (about 80%) with a history of neurogenic claudication or vesicorectal symptoms deteriorate with poor final outcome [98]. In view of these results, the indications for surgery should without doubt be stringently met and individualized. In view of this, treatment is dependent on the presence of a neurologic deficit either caused by a foraminal or a central stenosis. Treatment should therefore also take into account severity and duration of symptoms and comorbidities. With regard to the aforementioned aspects an etiology-based recommenda- tion of treatment modality can be given ( Table 4). Conservative Treatment Options The vast majority of spondy- lolisthesis patients can be treated non-operatively In general, the vast majority of patients with spondylolisthesis can be treated non-operatively ( Table 5). In patients with favorable indications for non-operative treatment, acute pain should be controlled with: activity modification (bedrest <3 days) pain medication anti-inflammatory drugs muscle relaxing drugs Spondylolisthesis Chapter 27 745 Table 4. Guidelines for treatment Etiology Age Low grade (Meyerding I–II) High grade (Meyerding III–IV) Asymptomatic Back pain only Back and neuro- logic symptoms Back pain only Back and neuro- logic symptoms Developmental children no treatment mostly non-operative surgical surgical surgical adults no treatment mostly non-operative mostly surgical non-operative or surgical surgical Degenerative adults no treatment non-operative or surgical usually surgical non-operative or surgical usually surgical Postsurgical children no treatment attempt non-operative surgical surgical surgical adults no treatment attempt non-operative surgical surgical surgical Pathologic children depending on etiology depending on etiology depending on etiology depending on etiology depending on etiology depending on etiology Trauma children depending on slippage surgical surgical adults surgical surgical surgical Table 5. Favorable indications for non-operative treatment no neurologic deficit high patient comorbidity tolerable pain threshold improvement by exercise program short duration of symptoms improvement by brace treatment In patients without neurologic deficit, asufficientconservative management program is a prerequisite before surgery is contemplated This is followed by a therapeutic exercise program with paraspinal and abdomi- nal strengthening to improve muscle strength, flexibility, endurance and balance (see Chapter 21 ). If pain does not subside sufficiently, the use of a brace or orthoses may be beneficial. Radicular symptoms in spondylolisthesis are a result of a herniated disc or a foraminal stenosis. In these cases, non-operative management is not equally suc- cessful when compared to mechanical low back pain. However, this does not mean that conservative care is inefficient. However, leg pain may require a longer trail of non-operative care to evaluate the efficacy [5]. The non-operative treat- ment can be supported by spinal injections (see Chapter 10 )toreduceinflam- mation and thus temporarily or even permanently eliminate leg pain: epidural blocks spondylolysis block nerve root blocks In patients with chronic recurrent back and leg pain a sufficient period of conser- vative management should be performed before operative options are seriously contemplated. It is essential that the surgeon is certain that the symptoms are in fact a result of the slippage. Non-spinal causes of leg pain need to be contem- plated and excluded. Children and adolescents with a low-grade spondylolisthesis are usually treated conservatively Children and adolescents with a low-grade spondylolisthesis (Meyerding I and II) are mostly treated non-operatively; yet particularly in adolescence these need to be closely observed, as it is then that they are most likely to progress [12, 33, 51]. One of the most important measures for dealing with pain is the stretch- ing of the hamstrings. These exercises will improve the clinical condition in the vast majority of the cases. 746 Section Spinal Deformities and Malformations An acute pars defect can be treated conservatively with a pantaloon cast In young patients with an acute pars defect, a lumbar brace treatment including onethighisavaluabletreatmentoption.Therationaleisthatbyminimizingflex- ion-extension movements of the lumbar spine, the brace will stabilize the acute fracture allowing the lysis to heal by bony bridging [72]. Furthermore the brace usually diminishes the pain significantly. This treatment is performed for 6–12 weeks, depending on the age and the symptoms of the patient ( Case Study 1 ). There are no given rules as to how long non-operative treatment should be continued. Generally speaking, if there is no neurologic deficit, intensive conser- vative management should be tried over a period of at least 3–6 months. How- ever, surgery should not be postponed in patients when clinical symptoms are concordant with the morphological alterations and an adequate trial of non- operative therapy has failed. Operative Treatment General Principles Thechoiceofsurgicaltreatmentgreatlydependsontheetiologyaswellasthe degree of slippage as outlined above. General objectives of surgical treatment are to: prevent further slip progression stabilize the segment correct lumbosacral kyphosis relieve back and leg pain reverse neurologic deficits Both patient age and degree of slippage differentiate absolute and relative indica- tions ( Table 6): Table 6. Indications for surgery Absolute indications Relative indications progressive neurologic defits slip progression in children/adolescents minor, non-progressive neurologic deficits radicular and claudication symptoms high-grade spondylolisthesis in children severe lumbosacral kyphosis with gait disturbance mechanical low-back pain non-responsive to non-operative care Progressive slips in children should be treated operatively High-grade developmental spondylolisthesis in adolescents should almost always be treated operatively. Those presenting with a sciatic crisis known as the Phalen-Dixon sign need immediate medical attention in the form of intravenous analgesics, bedrest and close neurologic monitoring. If the severe pain does not subside quickly or neurologic deficit is observed, early surgical management shouldbestrivedfor.Itmustbepointedoutthathigh-gradespondylolisthesis with either lysis or elongation of the pars constitutes a treatment challenge for even the most careful surgeon [94]. High-grade spondylolisthesis (Meyerding III and IV) in adults is treated according to the symptoms and biological age of the patient. While the young, otherwise healthy adult will biomechanically benefit from correction of deformity parameters and realignment of the spine with the sacrum, the elderly patient with comorbidity may only need decompression. Although Möller and Hedlund [69] were able to show that surgical management There is no general consensus on the optimal treatment regime for adult spondylolisthesis of adult spondylolisthesis can provide favorable clinical outcomes compared to a supervised exercise program, there is no general consensus as to what constitutes the optimal non-operative or operative treatment regime. The decision to recom- Spondylolisthesis Chapter 27 747 mend surgery to an adult patient with spondylolisthesis must therefore be indi- vidualized very carefully. Almost all cases of traumatic spondylolisthesis in the adult will need surgical management. Surgical Techniques Spondylolysis Repair An acute pars defect can be directly repaired by osteosynthesis In symptomatic cases with a very slight slippage and a verified fresh pars defect, an osteosynthesis using the Morscher screw and hook [35, 73] or direct repair by screw fixation (Buck’s f u sion [6, 14]) ( Fig. 6) or figure of eight wiring (Scott’s technique [19, 96]) may be justified. Each fixation technique significantly increases stiffness and returns the inter- vertebral rotational stiffness to nearly intact levels. Importantly the displacement across the defect is significantly suppressed by all these instrumentation tech- niques; yet the least motion is allowed with the screw-rod-hook fixation or Buck’s technique [19], making these the method of choice. The prognosis for these tech- niques is primarily determined by the time of surgery and whether displacement has already taken place. Overall direct osteosynthesis seems to be a compara- tively safe and effective treatment method, independent of which method is uti- lized in cases with spondylolysis and fresh pars defects [19, 124]. Decompression When decompression with laminectomy is performed, fusion is compulsory While a symptomatic disc herniation in the segment L4/5 with coexistent slip at L5/S1 can be treated by selective microsurgical decompression at L4/5 alone, a discectomy in the olisthetic segment should be avoided due to a high risk of addi- tional destabilization. Due to the nature of the slippage, foraminal stenosis can- not be addressed selectively without causing added instability. If neurologic symptoms necessitate decompression and a complete laminectomy (Gill’ s proce- dure [80]) is done, fusion is mandatory because of the destabilization. Care should be taken that all proliferative pseudarthrosis tissue is removed after the nerve roots have been identified. While neurologic deficit is a definite indication for decompression, there is an ongoing discussion as to whether in the face of radicular symptoms decompression is always necessary [44]. The argu- ment against decompression relates to the loss of the tension-band strength and subsequent potential instability that the removal of posterior elements may exac- erbate [44]. Long-term follow-up studies have shown that especially in children repositioning of the slippage by instrumentation can improve leg pain very soon after surgery [46]. Instrumented Versus Uninstrumented Fusion For many years, uninstrumented fusion in s itu hasbeenthegoldstandardfor the treatment of isthmic spondylolisthesis in children and adolescents [117] and still has strong advocates [91]. However, with the advent of pedicular fixation devices, many spine surgeons have now changed to an instrumented fusion because it facilitates aftertreatment [11, 13, 43, 47, 92, 105]. Outcome of instrumented fusion is not shown to be superior to non-instrumented fusion While the surgeon may well have the impression that instrumentation gives good primary stability and allows for a more precise realignment of the spinal column, studies randomizing isthmic spondylolisthesis patients with and without pedicle screws have not shown an improved fusion rate or improved clinical outcome with reduction and instrumentation [8, 62, 69]. The argument that a better realignment may be achieved with pedicle screws may be true but remains unproven. 748 Section Spinal Deformities and Malformations e f a b cd e Figure 6. Direct spondylolysis r epair a Isthmic spondylolisthesis at the level of L4/5 (arrow). b Reversed gantry CT demonstrating the bilateral spondylolysis. c, d Direct screw fixation and bone grafting of the defect. e, f Solid fusion of the defect at 1 year follow-up with complete resolution of pain. (Courtesy of University Hospital Balgrist). Spondylolisthesis Chapter 27 749 For the posterolateral fusion, the spine can be approached either by a midline skin incision or alternatively by bilateral muscle-splitting (Wiltse approach [117]). The transverse processes should be thoroughly denuded and decorticated, along with the lateral aspect of the facet joint and pedicle (see Chapter 20 ). Especially at the upper margin of the fusion, destruction of the facet joint should be avoided to avoid damage to the adjacent motion segment. Autologous cancellous bone should be packed over the transverse processes, the lateral facet joints and, if a mid line incision has been performed, along the decorticated spinous processes of the slipped motion segment. Bone is usually obtained from the iliac crest, though this may of course increase morbidity. The mainstay of surgery in children is spinal realignment and in the elderly patient spinal stabilization and decompression In contrast to treatment of adolescents and young adults where a primary aim of surgical treatment is correction of deformity and spinal realignment, the mainstay of surgery in the adult and elderly patient is decompression, whereby the aim is to relieve radicular and claudication symptoms (see Chapter 19 ). There is no general consensus about the indications for fusion surgery, the goals being to relieve back pain from a degenerated disc and facet joint by elimination of the instability. Indications for instrumentation are even more controversial [99], due to the higher complication rate. Slip Reduction The treatment of high-grade spondylolisthesis differs between children and adults,asdoesthatoflow-andhigh-gradeslipsinadults.Inlow-gradeslipsit remains uncertain whether an attempt to reduce the anterior slip is actually nec- essary or desirable. Often some degree of reduction is already achieved by the prone position and subsequent exposure of the spine [71]. In adult spondylolisthesis in situ fixation is a proven surgical method In high-grade slips in the adult, in situ fixation with or without decompres- sion, depending on the neurologic status, is a proven surgical method [20], espe- cially when intervertebral body space has markedly diminished. Reduction of the slipped vertebra remains controversial in this patient group [13, 33]. Consensus exists on the fact that partial reduction of the slip angle should be attempted if significant malalignment and foraminal stenosis is present. The aim is to decom- press neural structures, decrease the lumbosacral kyphosis and facilitate fusion. In cases where partial reduction has been achieved, anterior structural support should be contemplated to hold the reduction in place [20]. In children the aim of surgery is to correct sagittal alignment and lumbosacral kyphosis Especially in high-grade slips (Grade III–IV) in children, the aim of surgery is to correct sagittal alignment and lumbosacral kyphosis. By improving the bio- mechanics, the chances of solid fusion are significantly increased ( Case Study 2). Nonetheless the procedure remains a surgical challenge especially in view of the high complication rates ranging from 10% to 60% [11, 13, 21]. This has led some surgeons to perform in situ posterolateral spine arthrodesis for high-grade slips in children [12, 28] with satisfactory clinical results. Interbody Fusion Spondylolisthesisisperseaspinalinstabilityandaswithallformsofosteosyn- thesis good postoperative stability is needed to avoid non-union or implant Interbody fusion is recommended when reduction and/or distraction is performed breakage. Especially when repositioning and/or distraction is performed, an interbody structural support of the anterior column is crucial [11]. In cases where the anterior column has not been addressed biomechanically, fusion rates for posterolateral fusions vary from 100% [11, 29, 92] to as low as 33% [41, 50, 111]. Even in cases where fusion has been verified, authors report on patients who continue to suffer from what is presumed to be “discogenic back pain” [3, 47]. 750 Section Spinal Deformities and Malformations a b c d e f Case Study 2 A 10-year-old patient presented with hyperlordosis of the lumbar spine, sagittal malalignment (lumbosacral step-off), flexed knee position, tight hamstrings and paraspinal muscle spasm ( a). The patient was neurologically intact. CT and MRI of the lumbar spine demonstrated a spondyloptosis ( b). Note the dome shaped sacrum (b, c). The patient did not exhibit a spondylolysis but an elongated pars ( c). Surgery was performed to realign the spine by means of sacral dome osteotomy (for technique see Fig. 7), pedicular instrumentation at L4–S1, posterolateral fusion at L4/5 and interbody fusion at L5/S1 with correct sagittal realignment ( e, f ). At the latest follow-up, the patient was symptom free and had sub- stantially improved her sagittal balance. (Courtesy of University Hospital Balgrist). Spondylolisthesis Chapter 27 751 Table 7. Results of surgical treatment of high-grade spondylolisthesis with and without instrumentation Author Cases Type of spondylo- listhesis Patient age Follow- up Technique Complications/ outcome Conclusions Schuffle- barger et al. (2005) [85] 18 adoles- cent high- grade develop- mental 14 (10 –16) years 3.3 (2.3 –5) years Gill decom- pression, monosegmen- tal PLIF with Harm’s cages and autoge- nous iliac graft 2 structural complica- tions Retrospective study 0 neurologic complica- tions PLIF procedure provides near- anatomic correction of high- grade spondylolisthesis with- out significant complications. Anterior column support and posterior compressive instru- mentation help restore bio- mechanics and allow fusion 0 infections 0 pseudarthrosis 0 reoperations Grzegor- zewski et al. (2000) [23] 21 adoles- cent high- grade develop- mental 14.9 (9.4 – 19.3) years 12.8 (6–24.8) years PLF+iliac bone graft + immobiliza- tion in panta- loon cast 4 months 0 neurologic complica- tions 0 pseudarthrosis Retrospective study 5patientsshowedpro- gression of slip 1 year postop. In situ posterolateral arthrod- esis with large amount of bone graft followed by immo- bilization provides satisfac- tory results Molinari et al. (2002) [62] 37 adoles- cent high- grade develop- mental 13.5 (9–20) years 3.1 (2–10.1) years PLF (n =18)vs. circumferen- tial (n =19) fusion 39% pseudarthrosis for posterolateral proce- dure vs. 0% in circum- ferential fusion Retrospective study All patients who had pseudar- throsis achieved solid fusion with a second procedure involving 360° fusion with ante- rior column structural grafting Möller et al. (2000) [64] 77 adult low grade 39 (18 –55) years 2years PLFwith (n=37)vs. without (n=40)trans- pedicular fixation no significant differ- ence in fusion rate This prospective randomized trial suggests that the use of supplementary transpedicular instrumentation does not add to the fusion rate or improve clinical outcome levelofpainaswellas functional disability were very similar Bjarke et al. (2002) [7] 129 adult low grade 46 and 43.5 (20 –67) years 5years PLFwith (n=63)vs. without (n=66)trans- pedicular fixation instrumented group had 25% reoperation rate vs. 14 % for non- instrumented This prospective randomized trial showed that long-term functional outcome improved in both groups. Isthmic spondy- lolisthesis profited from non-in- strumentation while degenera- tive spondylolisthesis fared bet- ter with transpedicular fixation functional outcome similarinbothgroups Suk et al. (2001) [94] 56 adult low grade 45.9 and 51.3 (23 –70) years 2years PLFwith instrumenta- tion (n= 35) vs. ALIF with ped- icle screw fixa- tion (n=21) no difference in complication rate clinical outcome iden- tical Prospective study PLF led to significant loss of reduction ALIF with pedicle screw instrumentation was superior to PLF with instrumentation in terms of preventing reduc- tion loss for spondylolytic spondylolisthesis Kim et al. (1999) [40] 40 adult low grade ±42 (21 –62) years 2.3–3.6 years ALIF (n =20) vs. PLF with instrumenta- tion (n=20) fusion rate after 12 months over 90% for both methods Retrospective study satisfactory clinical results in 85% for ALIF and 90 % for PLF + instrumentation There was no statistically sig- nificant difference in clinical results between the two methods Brad- ford et al. (1990) [12] 22 adult high grade 5 (2–7.5) years First posterior decompres- sion + PLF + halo-traction, then in sec- ond proce- dure ALIF percentage of slippage pre- vs. postop. did not change substantially Retrospective study 4 patients had non- union Alignment of the sagittal plane was restored in 17 patients. Back pain and radicular symptoms were relieved in all but one patient postop. 1 cauda equi- na syndrome and 2 nerve root neuropathy, yet persisting neurologic deficit in only 1 patient at follow-up 752 Section Spinal Deformities and Malformations Table 7. (Cont.) Author Cases Type of spondylo- listhesis Patient age Follow- up Technique Complications/ outcome Conclusions Boos et al. (1993) [10] 10 adult high grade 4.7 (3.6 –6.3) years PLIF and PLF (n=6) vs. PLF (n=4) 5/6 patients with sole PLF had loss of reduc- tion, non-union and implant failure Retrospective study all patients with PLF + PLIF had fusion and no loss of reduction PLF + PLIF for spondyloptosis is a technically demanding pro- cedure. Permanent reduction and fusion is only obtained with combined interbody and posterolateral fusion Roca et al. (1999) [77] 14 adult high grade 21 years 2.5 years Lumbosacral decompres- sion + PLF + interbody fusion 6 patients with tran- sient motor deficit Retrospective study 2 pseudarthrosis Circumferential arthrodesis through a posterior approach isasafeandeffectivetech- nique for managing severe spondylolisthesis 13 excellent clinical results Fusion techniques can achieve posterior column stability, anterior column stability or both The fusion techniques available for this deformity can conceptually be divided into those that achieve posterior column stability, those that achieve anterior col- umn stability and combined approaches that achieve both. In cases where the spinal canal has to be decompressed and instrumentation is planned, it makes sense to perform a posterior lumbar interbody fusion (PLIF); yet this is certainly not mandatory ( Case Introduction). The choice of which approach to take will heavily depend on personal preference and familiarity with the approach, resources and infrastructure as well as back-up expertise in case of complica- tions. Anterior interbody fusion allows better disc removal and fusion Anterior techniques in spine fusion allow for a complete discectomy and very precise placement of an interbody implant or graft. Particularly the latter aspect is an advantage of the method, as larger structural grafts can be placed without the danger of dural sheath damage or nerve root injury. While disc height may thereby be restored and kyphosis diminished, there is ongoing discussion as to whether an adequate repositioning and thus improvement of sagittal alignment of the spine can be achieved by a single anterior procedure, with or without instrumentation. Also, because nerve root and dural sac are not decompressed before the repositioning maneuver, there is a high likelihood of neurologic injury. The method should therefore only be contemplated in low-grade olisthe- sis, where the primary aim is in situ stabilization and fusion without decompres- sion or repositioning in neurologically asymptomatic patients. In the lumbar spine the anterior technique usually involves a retroperitoneal approach, with its attendant complications such as possibility of vascular injury, damage of the sympathetic plexus with subsequent retrograde ejaculation in males, as well as damage to retro- and intraperitoneal structures. Spine surgeons performing this approach should therefore either be able to manage possible complications themselves or have very fast access to expertise. Circumferential arthrodesis offers the highest fusion rate Circumferential stability offers all the advantages of both the aforementioned techniques, yet obviously also incorporates the possible complications. Com- bined approaches can be either posterior or transforaminal interbody fusion (PLIF or TLIF) or anterior lumbar interbody fusion (ALIF) with posterolateral intertransverse fusion (PLF). Due to the high degree of primary stability achieved with the 360° treatment of the spine, fusion rates are highly reliable with numerous reports claiming rates of 100% [34, 100, 104, 123]. Also, an excel- lent spinal realignment can be achieved. Despite these good results, the tech- nique of 360° instrumentation is technically more demanding than ALIF or PLF alone. Spondylolisthesis Chapter 27 753 . mainstay of surgery in children is spinal realignment and in the elderly patient spinal stabilization and decompression In contrast to treatment of adolescents and young adults where a primary aim of. surgical treatment is correction of deformity and spinal realignment, the mainstay of surgery in the adult and elderly patient is decompression, whereby the aim is to relieve radicular and claudication. s itu hasbeenthegoldstandardfor the treatment of isthmic spondylolisthesis in children and adolescents [117] and still has strong advocates [91]. However, with the advent of pedicular fixation devices,