Spinal slip is a subluxation between a vertebra relative to another adjacent vertebra. Degenerative lumbar slip (DS) is acquired and is a common contributor to spinal stenosis. Clinicians need to have a thorough understanding of all treatment options in order to balance cost and efficacy in the treatment of each patient. Surgery Surgery needs to be considered for patients with severe symptoms and those who have failed conservative treatment. The best candidates for surgery are patients with radicular pain or neurogenic claudication, as they are often unable to stand for long periods of time or walk long distances. Patients with rectal or bladder dysfunction or progressive loss of function require more urgent surgical intervention. Most patients achieve a satisfactory outcome after surgery, with one study reporting a satisfaction rate of 86.6%. Although the number of surgical treatments for DS has increased over the past decade, laminectomy with medial partial synovectomy and decompression combined with instrumented fusion remains the standard, and all other new approaches need to be compared. Decompression alone without fusion The basic operation in DS surgery is decompression of the spinal stenosis. Laminectomy is the most common method of decompression, allowing direct decompression of the central canal, lateral socket, and neural foramina. Laminectomy is also an alternative decompression approach when the arch is concealed. Several early studies supported decompression in DS with reliable data.Mardjetko et al. published a meta-analysis in 1994 combining 11 studies and showed that 69% of patients who underwent decompression alone had a satisfactory outcome. Similar results were obtained in two subsequent publications by Epstein and Kristof et al, who performed decompression alone in elderly patients with satisfactory postoperative outcomes of 82% and 73.5%, respectively, without the presence of dynamic instability on lateral radiographs. Despite the fact that decompression fusion has now become the most common surgical procedure for the treatment of DS, several studies have resumed to devote attention to decompression alone in selected patients. Advocates of decompression alone argue that older patients with stable DS are better treated with this approach because of the lower incidence of symptoms and lethality. Decompression plus noninstrumented fusion The majority of current patients with DS are treated with neural decompression and lumbar fusion.Herkowitz and Kurz 1991, in a landmark prospective randomized study of 50 patients, found laminectomy plus fusion to be superior to laminectomy alone. Patients with laminectomy plus joint fixation had a significantly lower incidence of postoperative low back pain (p<0.01) and a higher overall clinical satisfaction rate (p=0.0001) than patients with laminectomy alone. Non-instrumented posterior posterolateral fusion (plf) using autogenous iliac bone graft with a mean follow-up of 3 years showed significant pseudoarthrosis in 36% of fusion cases, but did not have an impact on clinical outcomes in the time window of this study. In an updated series of retrospective studies, martin et al. also demonstrated the advantages of noninstrumented fusion for the treatment of ds. Decompression plus posterolateral instrumented fusion The use of posterolateral fixation instruments in DS fusion reduces the risk of pseudarthrosis formation, but its clinical outcome remains unclear.Fischgrund et al. divided 76 patients with DS into instrumented and noninstrumented unisegmental decompression and fusion groups in a classic study, and at a minimum 2-year follow-up found a higher rate of fusion in the instrumented fusion group (82% in the two groups and 45%), but there was no statistically significant difference in clinical outcomes between the two groups. A further study was done on 47 of these patients (mean follow-up 7 years and 8 months), and patients who obtained reliable fusions had significantly better clinical outcomes than those with pseudoarthrosis (p=0.01). The authors concluded that successful fusion is beneficial to clinical outcomes at long-term follow-up and that instrumented fusion should be considered in patients at risk for pseudoarthrosis. There are no long-term, high-quality studies of the association between fixation instrumentation and improved clinical outcomes in patients. However, sufficient data suggest that the use of immobilization improves fusion rates, making instrumented fusion the current standard of care. Degenerative Lumbar Spondylolisthesis and the SPORT Perspective The Spinal Disorders Clinical Outcomes Research Trial (SPORT) is a prospective multicenter trial that divided patients with symptomatic DS who underwent surgical and nonsurgical treatment into a randomized cohort and an observational cohort for comparative study. The randomized cohort consisted of 304 patients, while the observation cohort consisted of 303. This is the largest study on DS to date, and future studies should be evaluated against this standard. Surgery was posterior laminectomy and decompression with or without single-segment fusion, with or without fusion instrumentation. Nonoperative treatment included conventional clinical therapies. The authors attempted to analyze the two data sets using an intention-to-treat analysis, but there was a significant crossover between the two groups of cases, with only 64% of patients identifying surgery, whereas 49% of patients initially identified for nonoperative treatment but ultimately underwent surgery within 2 years. Receipt of treatment analyses, including both the randomized and observational cohorts after adjusting for potential confounders, amply demonstrated that the surgical group experienced a significant improvement in pain and function at the 2-year follow-up. this improvement was sustained at the 4-year follow-up, at which time patients in the surgical group experienced a mean reduction of 23 points in their Oswestry Disability Index (ODI) scores, compared with a mean reduction in the ODI scores of the nonsurgical group, with an efficacy difference of was 14.3 points (p<0.001). The sf-36 scale physical functioning score improved by 26.6 points in the surgical group compared to 7.7 points in the non-surgical group, with an efficacy difference of 18.9 points (p<0.001). In addition, 67.1% of surgical patients achieved improvement in major symptoms compared to 21% of non-surgical patients. The smallest clinically meaningful difference in odi scores for ds patients who underwent surgery was 14.9 points. Further analysis of the data from the SPORT study suggests that despite similar characteristics between patients with ds and patients with spinal stenosis, patients with ds have significantly better outcomes with surgical treatment than patients with spinal stenosis. Another analysis of the analyzed factors showed that patients with predominantly leg pain before surgery had more significant symptom improvement after surgery than patients with predominantly low back pain before surgery. The researchers also found that surgical patients improved more significantly than non-surgical patients, independent of the degree of slippage, disc height, and intervertebral mobility. In a further subgroup analysis of 380 ds patients, 80 patients underwent posterior-lateral in situ fusion, 213 underwent posterior-lateral instrumented fusion, 63 underwent 360° fusion, while 23 underwent decompression alone without fusion. During a 4-year follow-up, no consistent differences in clinical outcomes were found between the various fusion methods. In addition, no differences in clinical outcomes were found between the different bone grafting methods (e.g., posterior iliac spine bone graft, localized bone graft, allograft bone graft, and substitute bone graft) during the 4-year follow-up. In a subgroup analysis of patients with posterior iliac spine bone grafting, radcliff et al. also found that iliac spine bone grafting did not lead to increased postoperative complications or reoperation rates despite longer grafting times and more intraoperative bleeding. They further stated accordingly that autologous iliac spine bone graft patients were equivalent to non-iliac spine bone graft fusion patients in terms of overall clinical outcomes. sport data were also used to evaluate ds patients with multisegmental spinal stenosis. park et al. found that ds patients with only single-segment spinal stenosis had better surgical outcomes than those with multisegmental stenosis. smorgick et al. compared the results of a single segment lumbar spine slip with a combination of multisegmental spinal stenosis in patients with multisegmental stenosis. In patients with single-segment lumbar spinal slippage combined with multisegmental stenosis, they compared two surgical approaches, multisegmental decompression plus single-segment fusion or multisegmental fusion, and despite similar clinical outcomes, multisegmental fusion took longer and resulted in more intraoperative bleeding. Interbody fusion Additional interbody fusion in DS treatment is another point of controversy. Theoretically, interbody fusion increases the fusion area and improves the initial stability of the fused structure.The 2009 North American Society for Spine Surgery (NASS) guidelines raise the question of whether 360° fusion is more effective than decompression plus PLF alone. The authors found few relevant studies on this issue to make a recommendation. Since then, several studies have focused on this topic. Interbody fusion can be accomplished through a variety of surgical approaches, and different surgical approaches have their own advantages and disadvantages. Of all the interbody fusion approaches, anterior lumbar interbody fusion (ALIF) was one of the earliest, but not many studies have focused on ALIF in patients with DS. Advantages include indirect nerve root decompression, restoration of disc height and spinal sagittal sequence, repositioning of the anterior slip, and a larger space for graft embedment. Disadvantages include various surgical complications of the anterior lumbar approach.Satomi et al. compared ALIF with posterior decompression in 27 patients and found that JOA (Japanese Orthopaedic Association) clinical scores improved by 77% in patients undergoing ALIF, compared with a 56% improvement in the scores of patients undergoing posterior decompression.Fifty-six percent of the patients undergoing ALIF had an excellent improvement in their JOA scores, while posterior decompression patients had an excellent rate of 36 The JOA score improved to excellent in 56% of patients with ALIF compared to 36% of patients with posterior decompression. Similarly, Takahashi et al. found that 76% of DS patients who underwent ALIF were satisfied with the clinical outcome after 10 years of follow-up by JOA score.Kanamori et al. retrospectively studied 20 DS patients who underwent ALIF, and the rate of osseous fusion of grafted areas was 100% at the minimum 10 years of follow-up. However 6 patients required surgical intervention for symptoms of adjacent segmental disease (ASD). Posterior lumbar interbody fusion (PLIF) (Figure 3) and transforaminal lumbar interbody fusion (TLIF) provide direct access to the intervertebral space through a posterior approach, avoiding both the complications associated with anterior surgery and the reduction in operative time required due to both anterior and posterior approaches.TLIF has the added advantage of simpler arrival at the interforamen and intervertebral space, with less manipulation of neural tissue. In a retrospective study comparing TLIF and PLIF, both techniques were found to significantly improve clinical symptoms.The rate of good and excellent JOA functional disability scores was 84.1% (83.5% for PLIF and 84.6% for TLIF). Improvement in VAS pain scores was significant in both groups (p<0.001). The degree of slip repositioning, main keyboard height and intervertebral foraminal height recovery were significantly improved on imaging with both methods (p<0.05). TLIF was found to be safer and easier to perform than PLIF at 2-year follow-up.Ha et al. conducted a retrospective study of 40 patients with symptomatic DS at L4-5, comparing the results of two surgical approaches of decompression + PLF with or without PLIF. Slip <4 mm or slip angle <10° on preoperative hyperextension and hyperflexion radiographs was considered stable. At 2-year follow-up, patients with stable DS with combined PLIF did not have a significant advantage in their ODI and VAS scores, but patients with unstable DS with combined PLIF had a significantly better clinical outcome.Patients in the PLF group had 22% ± 16.1% fewer postoperative ODI scores, whereas patients in the PLF combined with PLIF group had a reduction in postoperative scores of 42.3% ± 17.9% (p=0.004). Further analysis revealed that the degree of disc height restoration was directly related to improved postoperative clinical outcomes. This study noted that preoperative determination of instability can determine the need for intraoperative interbody fusion.Lateral interbody fusion was proposed in 2006 as an alternative approach with less injury than traditional anterior and posterior interbody fusion. The advantages of this approach over the posterior approach include a lower risk of neurologic complications and less damage to posterior structures, and it reduces the risk of vascular and organ injury compared with the anterior approach. However, the posterolateral approach tends to be more difficult to manage and remediate in the event of any of these injuries. In addition, the lateral approach increases the risk of lumbar plexus injury during dissection of the psoas major muscle, leading to postoperative thigh pain, sensory deficits, and quadriceps weakness, which are transient in most cases.Pumberger et al. found in a retrospective study of 235 patients that sensory deficits were present in 28.7% of the patients at 6 weeks postoperatively, compared with only 1.6% at 12 months postoperatively, and that 41% had a sensory deficit at 6 weeks postoperatively, while 41% had a sensory deficit at 6 weeks postoperatively. had pain in the groin area and anterior thigh at 6 weeks postoperatively compared with 0.8% at 12 months postoperatively; Marchi et al. recently prospectively and nonrandomized controlled study of 52 patients with low-grade DS who underwent isolated posterolateral interbody fusion. At a minimum 24-month follow-up, the fusion rate was 86.5%, ODI scores improved by 54.5%, VAS scores improved by 60%, and the mean degree of slip resurfacing was 15.1%-7.1% (p<0.001). However 17% of patients had fusion settling and 13.5% had pseudarthrosis formation. In total 13% of patients underwent return surgery due to settling appearing unstable/recurrent spinal stenosis or inadequate decompression. The short-term clinical results and imaging performance of posterolateral interbody fusion are comparable to traditional anterior and posterior procedures, but it has the advantage of being more minimally invasive, and there is still a lack of information on mid- and long-term studies. Degenerative slip rarely exceeds degrees I and II because of the intrinsic stability that accompanies the disease process. If instrumented fusion is used, the posterior system alone is adequate for most patients with DS.The SPORT subgroup analyzed different fusion techniques and noted that there is no clear advantage to adding one fusion method to another. However, the addition of interbody fusion needs to be considered if there is a high risk of bone nonunion, the presence of localized kyphosis, high degree of slippage, symptomatic instability due to sagittal articular synovial joints, articular effusion on MRI and higher discs. Independent of the surgical approach, the goal of interbody fusion is to stabilize the anterior column, increase the fusion rate, and improve sagittal plane sequences and disc height. Another benefit of interbody fusion is the indirect decompression of the foramina. While pedicle screw fixation alone is biomechanically justified when the anterior column loads are well maintained, in cases of incomplete anterior column sequences (e.g., more than II degrees of slippage, excessive movement on power x-rays), pedicle screw fixation alone does not provide adequate stability, and the addition of an interbody fusion significantly improves the stability of the structure. Minimally Invasive Decompression Recent studies have shown that minimally invasive surgery (MIS) decompression of the stenotic spinal canal is comparable to open laminectomy with the assistance of a microscope and a tubular spacer. Minimally invasive decompression techniques continue to evolve, and although short-term results have been demonstrated, long-term follow-up studies are needed to observe any deterioration in outcomes, as is the case with traditional open laminectomy techniques for DS. Jang et al. retrospectively studied 21 patients with degree I DS with spinal stenosis who underwent minimally invasive lumbar laminoplasty (minimally invasive bipartite decompression via unilateral approach). After a minimum of 3 years of follow-up, ODI scores improved from 59.52 to 26.19, despite successive postoperative slippage in 10 of 22 segments at the earliest 18-month follow-up. The increase in postoperative slippage was particularly pronounced in patients with large sagittal movements on preoperative power radiographs, suggesting that decompression alone without fusion should only be applied to stable DS patients with smaller sagittal movements and incipient radicular symptoms.Kelleher et al. retrospectively examined 25 patients with predominantly lower extremity symptoms without low back pain or kinetic instability with degree I DS. Surgical measures were simple minimally invasive lumbar laminoplasty for decompression.ODI scores improved from 48 to 24.6 (p<0.001), and 77.8% of the patients were satisfied with the outcome at a mean follow-up of 31.8 months.Nine patients showed a mean of 8.4% progression of slippage, and two patients developed new slippage. The extent of the slips did not require revision. odi scores, revision rates, and dural injury rates improved better than the results of the sport study. Using a cost-effectiveness analysis, the authors found that minimally invasive decompression surgery saved approximately$8,330 Canadian dollars over conventional decompression single-segment fusion over the same 5-day hospital stay. Minimally invasive decompression fusion Wang et al. prospectively studied 85 patients with degenerative and isthmic cleft lumbar spondylolisthesis who were randomized into two groups: minimally invasive TLIF and open TLIF. The mean follow-up was 26.3 months, and the two groups were essentially similar in terms of operative time, ODI scores, and VAS scores for low back pain. Additional advantages for patients in the minimally invasive TLIF group were less total bleeding (p<0.01), lower postoperative low back pain VAS scores (p<0.05), and shorter hospital stay (p<0.05). Patients in the minimally invasive tlif group had more x-ray exposure. kim et al. reported the clinical and imaging results of minimally invasive tlif combined with percutaneous pedicle screw fixation in 19 degenerative lumbar slips and 25 isthmic cleft lumbar slips in a total of 44 patients. Postoperative odi scores and low back pain vas scores improved significantly (p<0.001) and were maintained at a minimum of 5 years of follow-up. The overall patient satisfaction rate was 80%. ct or power position radiographs demonstrated that fusion was obtained in all patients with ds. neighboring segmental lesions (asd) on imaging were found in 13 patients (68.4%), while symptomatic asd was seen in only 3 patients (15.8%). The authors concluded that minimally invasive tlif history is a safe and effective surgical procedure after a 5-year follow-up. Dynamic immobilization Dynamic immobilization as a method of preserving segmental mobility function aims to provide stability while overcoming the disadvantages of fusion and avoiding ASD.The role of dynamic immobilization in the treatment of unisegmental DS was prospectively studied by Schaeren et al. Nineteen out of twenty-six patients were given a minimum of 4 years of follow-up.The authors concluded that dynamic immobilization is a safe and effective method for the treatment of unisegmental DS. Lower extremity pain VAS scores and walking distance improved significantly (p<0.001), and claudication disappeared in 84% of patients. On imaging, lumbar slippage did not progress and the mobile segments remained stable. 4 patients (21%) experienced internal fixation failure, with 3 experiencing asymptomatic screw loosening and 1 experiencing significant screw loosening and fracture. 47% of the patients experienced asd. Overall patient satisfaction was high, with 79% reporting that they were certain they could withstand the same procedure again, and 16% reporting that they were likely to be able to withstand the same procedure again. The authors concluded that decompression with dynamic fixation was the best option. The authors concluded that decompression with dynamic fixation maintained clinical outcomes and imaging stability over 4 years and could be an alternative to fusion. However, in this series of studies, dynamic fixation was found not to prevent the development of asd. Similar clinical and imaging results were obtained in a retrospective analysis consisting of 39 patients with a mean follow-up of 7.2 years. At final follow-up, the grob questionnaire showed improvement in low back pain in 89% of patients and lower extremity pain in 86%. 92% of patients reported being able to tolerate the same procedure again. mild degenerative progression was detected on imaging in 9 patients, and the presence of asd on imaging was observed in 18 patients, although these changes did not correlate with the clinical picture. 8 patients required reoperation, 6 of whom had to have another procedure due to symptomatic asd, 1 due to delayed infection, and 1 with screw fracture.Functional fusion was observed in 73% of the endoprosthetic segments, which led the authors to hypothesize that the dynamic stabilization system was acting as a fusion device. Thus the clinical results produced by the dynamic fusion technique were not achieved because of its preservation of segmental mobility. Lumbar Interspinous Spacer Currently there are a variety of FDA-approved interspinous devices (ISDs) in use. Although these devices differ in both design and composition, their common purpose is to prop open adjacent spinous structures to increase spinal canal diameter and reduce segmental distraction.Kabir et al. 2010 conducted a series of retrospective studies on the clinical and biomechanical aspects of the various interspinous spacer devices currently in use. Although they found new biomechanical evidence to support the advantages of ISDs in the dynamics of spinal degeneration, clinical studies on them were inconclusive.Anderson et al. did a prospective randomized study on this topic, with a sample of 75 patients with DS of degree I with neurologic claudication.42 underwent implantation of the X-STOP device (Medtronic Inc.), and 33 did not undergo surgery. Zurich Claudication Questionnaire scores, patient satisfaction, and SF-36 scale scores improved significantly in the ISD group, whereas no significant changes were observed in the control group. 2-year follow-up revealed an overall clinical success rate of 63.4% in the operated group and only 12.9% in the non-operated group. Comparative studies between this endoprosthesis and other standard surgical procedures are lacking. Lumbar interspinous bracing devices may be beneficial in specific groups of patients. High-quality studies are needed to fully elucidate the rational use of ISDs and long-term follow-up is required. Degenerative Lumbar Slip in the Elderly With increasing life expectancy and a growing geriatric population, spine surgeons will be confronted with an increasing number of elderly patients with degenerative spinal conditions. In general, older patients are at higher risk for postoperative complications due to their age-related concomitant diseases. The most significant problems in this patient population are pseudoarthrosis, endoprosthesis failure or loosening due to bone loss, and a continued increase in the number and severity of concomitant diseases with a resulting high risk of perioperative complications.Rodgers et al. found that, in a group of 80-90 year olds undergoing minimally invasive transforaminal lumbar psoas fusion, the complication rate, bleeding/transfusion ratio, and mean length of hospital stay were significantly lower than in open surgery. and mean length of hospitalization were significantly lower than those with open PLIF (p<0.0001). Other studies confirm this result. lee et al. studied the outcome of minimally invasive tlif in elderly patients and found significant improvement in vas and odi scores (p<0.001) at a minimum of 36 months follow-up, with 88.9% of patients having a satisfactory clinical outcome and a low complication rate of 7.4%. The rate of pseudoarthrosis formation was 22.2% and 44.4% of patients presented with adjacent segmental lesions. However, all patients who did not achieve reliable fusion did not undergo reoperation and had a successful clinical outcome. Other studies have shown that conventional decompression with instrumented plf in elderly patients also resulted in satisfactory clinical and imaging outcomes with fewer complications. Age alone should not be a contraindication to surgery. Rational selection of surgical indications, preoperative optimization and effective perioperative drug therapy are factors that influence the success of surgery in elderly patients. COST-EFFECTIVENESS AND COST-UTILITY ANALYSIS OF DS TREATMENTS It is important for clinicians to have a cost-benefit awareness between measures to improve the quality of life of their patients and the socioeconomic impact. Cost-effectiveness analysis compares the cost-effectiveness ratio of two or more treatments. Treatment effectiveness is assessed by health-adjusted quality of life years (QALYs), which take into account both quality of life and length of life, and is usually evaluated using standardized instruments such as the European Five Dimensional Health Scale. The cost of a treatment needs to include both direct costs (e.g. resource use, health care costs) and indirect costs (e.g. loss of labor). The increased cost-effectiveness ratio is calculated by the difference in the value-added of the QALYs between the two treatment groups. There is currently no definitive cost-effectiveness threshold in the United States, but when the increase in the cost-effectiveness ratio is less than$50,000 per QALY, the treatment is generally recognized as cost-effective. In cost-utility analyses, QALYs are derived by applying different utility weights (0 for death and 1 for perfect health) to calculate the correlation between expected and actual survival life. With the focus on cost-effectiveness in medicine and increased scrutiny of the economic value of spinal surgery, there are now a growing number of findings for or against surgical treatment. A recent subgroup analysis of SPORT outcome data showed that surgical approaches to DS were not highly cost-effective at 2-year follow-up and were cost-effective at 4-year follow-up. There was no cost-effectiveness difference between different fusion types. In an analysis of 45 patients with DS who underwent TLIF, Adogwa et al. reported a cost per QALY of$42,854 after 2 years of follow-up, an outcome that is more favorable than current approaches that are generally considered cost-effective, such as total hip and total knee arthroplasty. The authors emphasize the difficulty of obtaining true utility (QALYs obtained), primarily due to the variability of patient selection and the potential exaggeration of QALYs in medical research. With the resurgence of minimally invasive subacute simple decompression, Kim et al. analyzed the cost of minimally invasive decompression techniques and found that despite the slight advantage of decompression plus fusion in terms of clinical outcomes, minimally invasive subacute simple decompression had better cost-effectiveness, saving costs while making the procedure easier to perform. Similarly, Parker et al. found that patients treated with minimally invasive sub-TLIF had shorter hospital stays and were able to return to work earlier than those treated with incisional TLIF, resulting in greater cost savings. The authors also emphasized the importance of indirect costs. Total joint arthroplasty (TJA) is recognized as a cost-effective method of restoring a healthy quality of life, and therefore TJA can be used as a benchmark for clinical outcome expectations. Lumbar spine surgery, on the other hand, is not as widely accepted as TJA because of its variable outcomes. Several scholars have investigated whether lumbar fusion and TJA can achieve equivalent outcomes in the same age group. According to these studies, it was found that patients who underwent lumbar decompression and fusion were able to regain a healthy quality of life in the same age group, an outcome similar to that of patients with TJA. Summary The surgical treatment of DS continues to evolve. According to the senior author (F.J.E.), laminectomy alone is the ideal treatment if DS is stable. Laminectomy with posterior instrumented fusion is currently the most widely used as the current standard approach for the treatment of DS.TLIF and PLIF are best suited for patients who need to be provided with additional stability.Fusion requires a larger bony interface with the goal of improving the kyphosis, which would otherwise be more severe in terms of low back pain than lower extremity pain. ALIF combined with percutaneous screw fixation provides the same anterior support but requires a higher degree of skill and experience in the surgeon's anterior approach. Lateral transforaminal lumbaris major interbody fusion combined with percutaneous pedicle screw fixation reduces the risk of new postoperative inguinal area and thigh symptoms. Each surgical approach has its own learning curve, and comparative data are available between the different approaches. When deciding on the appropriate surgical approach, the surgeon needs to consider his or her familiarity with the technique, understand the potential risks and benefits, weigh the cost of the endoprosthesis against the duration of the procedure, and consider the patient's length of hospitalization and return to work.