A Comparison of Various Surgical Treatments for Degenerative Cervical Myelopathy: A Propensity Score Matched Analysis

Efficacy and safety of laminoplasty combined with C3 laminectomy for patients with multilevel degenerative cervical myelopathy: a systematic review and meta-analysis

PURPOSE

Laminoplasty (LP) combined with C3 laminectomy (LN) can effectively achieve spinal cord decompression while maintaining the integrity of the posterior ligament-muscle complex, thereby minimizing cervical muscle damage. However, its necessity and safety remain controversial. This study aimed to compare the safety and efficacy of LP and LP combined with C3 LN in the treatment of patients with multilevel degenerative cervical spondylotic myelopathy (DCM).

METHODS

A systematic review and meta-analysis of the literature was performed. A search of PubMed, Web of Science, Embase, and the Cochrane Library databases was conducted from inception through December 2023 and updated in February 2024. Search terms included laminoplasty, laminectomy, C3 and degenerative cervical spondylosis. The literature search yielded 14 studies that met our inclusion criteria. Outcomes included radiographic results, neck pain, neurologic function, surgical parameters, and postoperative complications. We also assessed methodologic quality, publication bias, and quality of evidence.

RESULTS

Fourteen studies were identified, including 590 patients who underwent LP combined with C3 LN (modified group, MG) compared to 669 patients who underwent LP (traditional group, TG). The results of the study indicated a statistically significant improvement in cervical range of motion (WMD = 3.62, 95% CI: 0.39 to 6.85) and cervical sagittal angle (WMD = 2.07, 95% CI: 0.40 to 3.74) in the MG compared to the TG at the last follow-up (very low-level evidence). The TG had a higher number of patients with complications, especially C2-3 bone fusion. There was no significant difference found in improvement of neck pain, JOA, NDI, cSVA, T1 slope at latest follow-up.

CONCLUSION

LP combined with C3 LN is an effective and necessary surgical method for multilevel DCM patients to maintain cervical sagittal balance. However, due to the low quality of evidence in existing studies, more and higher quality research on the technology is needed in the future.

A Comparison of Clinical Outcomes Between Anterior Cervical Discectomy and Fusion Versus Posterior Cervical Laminoplasty for Multilevel Cervical Myelopathy

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

To compare patient-reported outcomes and surgical outcomes after anterior cervical discectomy and fusion (ACDF) versus cervical laminoplasty for multilevel cervical spondylotic myelopathy.

BACKGROUND

Treatment options for multilevel cervical spondylotic myelopathy include ACDF and cervical laminoplasty. Given that the literature has been mixed regarding the optimal approach, especially in patients without kyphosis, there is a need for additional studies investigating outcomes between ACDF and cervical laminoplasty.

METHODS

A retrospective review was conducted of adult patients undergoing 3 or 4-level surgery. Patients with preoperative kyphosis based on C2-C7 Cobb angles were excluded. The electronic medical record and institutional databases were reviewed for baseline characteristics, surgical outcomes, and patient-reported outcomes.

RESULTS

A total of 101 patients who underwent ACDF and 52 patients who underwent laminoplasty were included in the study. The laminoplasty cohort had a higher overall Charlson Comorbidity Index (3.10 ± 1.43 vs 2.39 ± 1.57, P = 0.011). Both groups had a comparable number of levels decompressed, C2-C7 lordosis, and diagnosis of myelopathy versus myeloradiculopathy. Patients who underwent laminoplasty had a longer length of stay (2.04 ± 1.15 vs 1.48 ± 0.70, P = 0.003) but readmission, complication, and revision rates were similar. Both groups had similar improvement in myelopathy scores (∆modified Japanese Orthopedic Association: 1.11 ± 3.09 vs 1.06 ± 3.37, P = 0.639). ACDF had greater improvement in Neck Disability Index (∆Neck Disability Index: -11.66 ± 19.2 vs -1.13 ± 11.2, P < 0.001), neck pain (∆Visual Analog Scale-neck: -2.69 ± 2.78 vs -0.83 ± 2.55, P = 0.003), and arm pain (∆Visual Analog Scale-arm: -2.47 ± 3.15 vs -0.48 ± 3.19, P = 0.010). These findings persisted in multivariate analysis except for Neck Disability Index.

CONCLUSION

ACDF and cervical laminoplasty appear equally efficacious at halting myelopathic progression. However, patients who underwent ACDF had greater improvements in arm pain at 1 year postoperatively. Longitudinal studies evaluating the efficacy of laminoplasty to mitigate adjacent segment disease are indicated to establish a robust risk-benefit assessment for these 2 procedures.

LEVEL OF EVIDENCE

III.

Relationship between intervertebral disc height and post operative dysphagia secondary to single-level anterior cervical discectomy and fusion- a retrospective study

BACKGROUND

One goal of Anterior Cervical Discectomy and Fusion (ACDF) is to restore the loss of intervertebral disc height (IDH) results from the degenerative process. However, the effects of IDH on postoperative dysphagia after ACDF remain unclear.

METHODS

Based on the results of a one-year telephone follow-up, A total of 217 consecutive patients after single-level ACDF were enrolled. They were divided into dysphagia and non-dysphagia groups. The age, BMI, operation time and blood loss of all patients were collected from the medical record system and compared between patients with and without dysphagia. Radiologically, IDH, spinous process distance (SP) of the operated segment, and C2-7 angle (C2-7 A) were measured preoperatively and postoperatively. The relationship between changes in these radiological parameters and the development of dysphagia was analyzed.

RESULTS

Sixty-three (29%) cases exhibited postoperative dysphagia. The mean changes in IDH, SP, and C2-7 A were 2.84 mm, -1.54 mm, and 4.82 degrees, respectively. Changes in IDH (P = 0.001) and changes in C2-7 A (P = 0.000) showed significant differences between dysphagia and non-dysphagia patients. Increased IDH and increased C2-7 A (P = 0.037 and 0.003, respectively) significantly and independently influenced the incidence of postoperative dysphagia. When the change in IDH was ≥ 3 mm, the chance of developing postoperative dysphagia for this patient was significantly greater. No significant relationship was observed between the change in spinous process distance (SP) and the incidence of dysphagia. The age, BMI, operation time and blood loss did not significantly influence the incidence of postoperative dysphagia.

CONCLUSION

The change in IDH could be regarded as a predictive factor for postoperative dysphagia after single-level ACDF.

The role of comprehensive rehabilitation in the care of degenerative cervical myelopathy

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To find out if comprehensive rehabilitation itself can improve daily performance in persons with DCM.

SETTING

The spinal department of a rehabilitation hospital.

METHODS

Data from 116 DCM inpatients who underwent comprehensive rehabilitation after spinal surgery were retrospectively analyzed. The definitions of the calculated outcome variables made possible analyses that distinguished the effect of rehabilitation from that of spinal surgery. Paired t-tests were used to compare admission with discharge outcomes and functional gains. Spearman's correlations were used to assess relationships between performance gain during rehabilitation and between time from surgery to rehabilitation.

RESULTS

The Spinal Cord Injury Ability Realization Measurement Index (SCI-ARMI) increased during rehabilitation from 57 (24) to 78 (19) (p < 0.001). The Spinal Cord Independence Measure 3rd version (SCIM III) gain attributed to neurological improvement (dSCIM-IIIn) was 6.3 (9.2), and that attributed to rehabilitation (dSCIM-IIIr) 16 (18.5) (p < 0.001). dSCIM-IIIr showed a rather weak negative correlation with time from spinal surgery to rehabilitation (r = -0.42, p < 0.001).

CONCLUSIONS

The study showed, for the first time, that comprehensive rehabilitation can achieve considerable functional improvement for persons with DCM of any degree, beyond that of spinal surgery. Combined with previously published evidence, this indicates that comprehensive rehabilitation can be considered for persons with DCM of any functional degree, before surgery.

Full endoscopic laminotomy decompression versus anterior cervical discectomy and fusion for the treatment of single-segment cervical spinal stenosis: a retrospective, propensity score-matched study

OBJECTIVE

Anterior cervical discectomy and fusion (ACDF) is the standard procedure for the treatment of cervical spinal stenosis (CSS), but complications such as adjacent segment degeneration can seriously affect the long-term efficacy. Currently, posterior endoscopic surgery has been increasingly used in the clinical treatment of CSS. The aim of this study was to compare the clinical outcomes of single-segment CSS patients who underwent full endoscopic laminotomy decompression or ACDF.

METHODS

138 CSS patients who met the inclusion criteria from June 2018 to August 2020 were retrospectively analyzed and divided into endoscopic and ACDF groups. The propensity score matching (PSM) method was used to adjust the imbalanced confounding variables between the groups. Then, perioperative data were recorded and clinical outcomes were compared, including functional scores and imaging data. Functional scores included Visual Analog Scale of Arms (A-VAS) and Neck pain (N-VAS), Japanese Orthopedic Association score (JOA), Neck Disability Index (NDI), and imaging data included Disc Height Index (DHI), Cervical range of motion (ROM), and Ratio of grey scale (RVG).

RESULTS

After PSM, 84 patients were included in the study and followed for 24-30 months. The endoscopic group was significantly superior to the ACDF group in terms of operative time, intraoperative blood loss, incision length, and hospital stay (P < 0.001). Postoperative N-VAS, A-VAS, JOA, and NDI were significantly improved in both groups compared with the preoperative period (P < 0.001), and the endoscopic group showed better improvement at 7 days postoperatively (P < 0.05). The ROM changes of adjacent segments were significantly larger in the ACDF group at 12 months postoperatively and at the last follow-up (P < 0.05). The RVG of adjacent segments showed a decreasing trend, and the decrease was more marked in the ACDF group at last follow-up (P < 0.05). According to the modified MacNab criteria, the excellent and good rates in the endoscopic group and ACDF group were 90.48% and 88.10%, respectively, with no statistically significant difference (P > 0.05).

CONCLUSION

Full endoscopic laminotomy decompression is demonstrated to be an efficacious alternative technique to traditional ACDF for the treatment of single-segment CSS, with the advantages of less trauma, faster recovery, and less impact on cervical spine kinematics and adjacent segmental degeneration.

A Comparison of Short-Term Outcomes after Surgical Treatment of Multilevel Degenerative Cervical Myelopathy in the Geriatric Patient Population: An Analysis of the National Surgical Quality Improvement Program Database 2010-2020

STUDY DESIGN

Retrospective review of the American College of Surgeons-National Surgical Quality Improvement Program database from 2010 to 2020.

PURPOSE

To compare the short-term complication rates of anterior cervical decompression and fusion (ACDF), posterior cervical laminoplasty (LP), and posterior cervical laminectomy and fusion (PCF) in a geriatric population.

OVERVIEW OF LITERATURE

The geriatric population in the United States has increased significantly. Degenerative cervical myelopathy (DCM) is caused by cervical spinal stenosis, and its prevalence increases with age. Therefore, the incidence of multilevel DCM requiring surgical intervention is likely to increase. ACDF, LP, and PCF are the most commonly used surgical techniques for treating multilevel DCM. However, there is uncertainty regarding the optimal surgical technique for the decompression of DCM in geriatric patients.

METHODS

Patients aged 65 years who had undergone either multilevel ACDF, LP, or PCF for the treatment of DCM were analyzed. Additional analysis was performed by standardizing the data for the American Society of Anesthesiologists classification scores and preoperative functional status.

RESULTS

A total of 23,129 patients were identified. Patients with ACDF were younger, more often female, and preoperatively healthier than those in the other two groups. The estimated postoperative mortality and morbidity, mean operation time, and length of hospital stay were the lowest for ACDF, second lowest for LP, and highest for PCF. The readmission and reoperation rates were comparable between ACDF and LP; however, both were significantly lower than PCF.

CONCLUSIONS

PCF is associated with the highest risk of mortality, morbidity, unplanned reoperation, and unplanned readmission in the short-term postoperative period in patients aged 65 years. In contrast, ACDF carries the lowest risk. However, some disease-specific factors may require posterior treatment. For these cases, LP should be included in the preoperative discussion when determining the ideal surgical approach for geriatric patients.

Perioperative and safety outcomes following tissue-sparing posterior cervical fusion to revise a pseudarthrosis: A multicenter retrospective review of 150 cases

Background

Posterior cervical fusion (PCF) with lateral mass screws is a favorable treatment option to revise a symptomatic pseudarthrosis due to reliable rates of arthrodesis; however, this technique introduces elevated risk for wound infection and hospital readmission. A tissue-sparing PCF approach involving facet fixation instrumentation reduces the rates of postoperative complications while stabilizing the symptomatic level to achieve arthrodesis; however, these outcomes have been limited to small study cohorts from individual surgeons commonly with mixed indications for treatment.

Materials and Methods

One hundred and fifty cases were identified from a retrospective chart review performed by seven surgeons across six sites in the United States. All cases involved PCF revision for a pseudarthrosis at one or more levels from C3 to C7 following anterior cervical discectomy and fusion (ACDF). PCF was performed using a tissue-sparing technique with facet instrumentation. Cases involving additional supplemental fixation such as lateral mass screws, rods, wires, or other hardware were excluded. Demographics, operative notes, postoperative complications, hospital readmission, and subsequent surgical interventions were summarized as an entire cohort and according to the following risk factors: age, sex, number of levels revised, body mass index (BMI), and history of nicotine use.

Results

The average age of patients at the time of PCF revision was 55 ± 11 years and 63% were female. The average BMI was 29 ± 6 kg/m2 and 19% reported a history of nicotine use. Postoperative follow-up visits were available with a median of 68 days (interquartile range = 41-209 days) from revision PCF. There were 91 1-level, 49 2-level, 8 3-level, and 2 4±-level PCF revision cases. The mean operative duration was 52 ± 3 min with an estimated blood loss of 14 ± 1.5cc. Participants were discharged an average of 1 ± 0.05 days following surgery. Multilevel treatment resulted in longer procedure times (single = 45 min, multi = 59 min, P = 0.01) but did not impact estimated blood loss (P = 0.94). Total nights in the hospital increased by 0.2 nights with multilevel treatment (P = 0.01). Sex, age, nicotine history, and BMI had no effect on recorded perioperative outcomes. There was one instance of rehospitalization due to deep-vein thrombosis, one instance of persistent pseudarthrosis at the revised level treated with ACDF, and four instances of adjacent segment disease. In patients initially treated with multilevel ACDF, revisions occurred most commonly on the caudal level (48% of revised levels), followed by the cranial (43%), and least often in the middle level (9%).

Conclusions

This chart review of perioperative and safety outcomes provides evidence in support of tissue-sparing PCF with facet instrumentation as a treatment for symptomatic pseudarthrosis after ACDF. The most common locations requiring revision were the caudal and cranial levels. Operative duration and estimated blood loss were favorable when compared to open alternatives. There were no instances of postoperative wound infection, and the majority of patients were discharged the day following surgery.

Subclinical respiratory dysfunction and impaired ventilatory adaptation in degenerative cervical myelopathy

Degenerative cervical myelopathy (DCM) is a debilitating neurological condition characterized by chronic compression of the cervical spinal cord leading to impaired upper and lower limb function. Despite damage to areas of the cervical spinal cord that house the respiratory network, respiratory dysfunction is not a common symptom of DCM. However, DCM may be associated with respiratory dysfunction, and this can affect the ventilatory response to respiratory challenges during emergence from anesthesia, exercise, or pulmonary disease. Surgical spinal cord decompression, which is the primary treatment for DCM, leads to improved sensorimotor function in DCM; yet its impact on respiratory function is unknown. Here, using a clinically relevant model of DCM, we evaluate respiratory function during disease progression and assess adaptive ventilation to hypercapnic challenge before and after surgical intervention. We show that despite significant and progressive forelimb and locomotor deficits, there was no significant decline in eupneic ventilation from the early to late phases of spinal cord compression. Additionally, for the first time, we demonstrate that despite normal ventilation under resting conditions, DCM impairs acute adaptive ventilatory ability in response to hypercapnia. Remarkably, akin to DCM patients, surgical decompression treatment improved sensorimotor function in a subset of mice. In contrast, none of the mice that underwent surgical decompression recovered their ability to respond to hypercapnic ventilatory challenge. These findings underscore the impact of chronic spinal cord compression on respiratory function, highlighting the challenges associated with ventilatory response to respiratory challenges in individuals with DCM. This research highlights the impact of cervical spinal cord compression on respiratory dysfunction in DCM, as well as the persistence of adaptive ventilatory dysfunction after surgical spinal cord decompression. These results indicate the need for additional interventions to enhance recovery of respiratory function after surgery for DCM.

Failure of Surgical Equipoise in Posterior Cord Syndrome Myelopathy

We suggest that a clinical diagnosis of posterior cord syndrome indicates primary posterior decompression in cervical spondylotic myelopathy cases. We present two unique cases of failed anterior decompression in neutrally aligned necks with compressive myelopathy and a literature review. Two recent cases of cervical spondylotic myelopathy that failed to respond after anterior surgical decompression and fusion surgery were observed at our institution. Both patients had motor strength preservation but were unable to stand and walk independently and had other clinical findings consistent with posterior cord syndrome rather than the more common anterior or central cord syndromes, and both responded well to staged posterior decompression. Posterior cervical decompression successfully relieved posterior cord syndrome symptoms after a failed anterior decompression in both of our cases. Posterior cord syndrome is a rare syndrome best diagnosed clinically and should be considered in cases of cervical spondylotic myelopathy in which motor strength testing is preserved.

Comparison of Flexion Relaxation Phenomenon After Single-Level and Multi-Level Anterior Cervical Discectomy and Fusion

BACKGROUND

This prospective cohort study aimed to assess the influence of the number of fused segments in cervical paravertebral muscles by comparing the changes of the cervical flexion relaxation phenomenon (FRP) after single-level versus multilevel anterior cervical discectomy and fusion (ACDF).

METHODS

A total of 115 patients who had undergone ACDF were retrospectively recruited and divided into a 1-level group (n = 44), a 2-level group (n = 40) and a 3- to 4-level group (n = 31). The flexion relaxation experiment was carried out 3 days preoperatively and 12 months postoperatively by surface electromyography (SEMG). Patients were examined using the neck visual analog scale, cervical Japanese Orthopedic Association score, Neck Disability Index, and C2-C7 range of motion (ROM).

RESULTS

There was a significant difference in the time-related changes in flexion relaxation ratio (FRR) among the 3 study groups before and after surgery (F = 85.701; P < .001). Thirty-five patients (79.55%) with 1-level ACDF and 11 patients (27.5%) with 2-level ACDF had FRP were restored to normal at 12 months postoperatively; however, only 1 patient (3.33%) had normalized FRP after 3- to 4-level ACDF. There were significant differences in the time-related changes of the normalized SEMG root mean square values in each phase before and after surgery (P = .018, <.001, <.001, and <.001). A significant correlation was found between the changes in C2-C7 ROM and FRR in the 3 study groups (P = .007 for 1 level, P = .003 for 2 levels, and P = .036 for 3-4 levels).

CONCLUSIONS

Single-level ACDF contributes to normalizing the FRP of cervical paravertebral muscles, which is not ideally recovered by 2-level ACDF. In contrast, 3- or 4-level ACDF could not normalize the cervical FRP. Our research supports the passive structure hypothesis.

Trends in cervical laminoplasty and 30-day postoperative complications: 10-year results from a retrospective, multi-institutional study of 1095 patients

PURPOSE

This study aimed to investigate the recent 10-year trends in cervical laminoplasty and 30-day postoperative complications.

METHODS

This retrospective multi-institutional cohort study enrolled patients who underwent laminoplasty for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament. The primary outcome was the occurrence of all-cause 30-day complications. Trends were investigated and compared in the early (2008-2012) and late (2013-2017) periods.

RESULTS

Among 1095 patients (mean age, 66 years; 762 [70%] male), 542 and 553 patients were treated in the early and late periods, respectively. In the late period, patients were older at surgery (65 years vs. 68 years), there were more males (66% vs. 73%), and open-door laminoplasty (50% vs. 69%) was the preferred procedure, while %CSM (77% vs. 78%) and the perioperative JOA scores were similar to the early period. During the study period, the rate of preservation of the posterior muscle-ligament complex attached to the C2/C7-spinous process (C2, 89% vs. 93%; C7, 62% vs. 85%) increased and the number of laminoplasty levels (3.7 vs. 3.1) decreased. While the 30-day complication rate remained stable (3.9% vs. 3.4%), C5 palsy tended to decrease (2.4% vs. 0.9%, P = 0.059); superficial SSI increased significantly (0% vs. 1.3%, P = 0.015), while the decreased incidence of deep SSI did not reach statistical significance (0.6% vs. 0.2%).

CONCLUSIONS

From 2008 to 2017, there were trends toward increasing age at surgery and surgeons' preference for refined open-door laminoplasty. The 30-day complication rate remained stable, but the C5 palsy rate halved.

The Impact of Preoperative Myelopathy on Postoperative Outcomes among Anterior Cervical Discectomy and Fusion Procedures in the Nonelderly Adult Population: A Propensity-Score Matched Study

STUDY DESIGN

Retrospective cohort study.

PURPOSE

Anterior cervical discectomy and fusion (ACDF) is a common surgical intervention for patients diagnosed with cervical degenerative diseases with or without myelopathy. A thorough understanding of outcomes in patients with and without myelopathy undergoing ACDF is required because of the widespread utilization of ACDF for these indications.

OVERVIEW OF LITERATURE

Non-ACDF approaches achieved inferior outcomes in certain myelopathic cases. Studies have compared patient outcomes across procedures, but few have compared outcomes concerning myelopathic versus nonmyelopathic cohorts.

METHODS

The MarketScan database was queried from 2007 to 2016 to identify adult patients who were ≤65 years old, and underwent ACDF using the international classification of diseases 9th version and current procedural terminology codes. Nearest neighbor propensity-score matching was employed to balance patient demographics and operative characteristics between myelopathic and nonmyelopathic cohorts.

RESULTS

Of 107,480 patients who met the inclusion criteria, 29,152 (27.1%) were diagnosed with myelopathy. At baseline, the median age of patients with myelopathy was higher (52 years vs. 50 years, p <0.001), and they had a higher comorbidity burden (mean Charlson comorbidity index, 1.92 vs. 1.58; p <0.001) than patients without myelopathy. Patients with myelopathy were more likely to undergo surgical revision at 2 years (odds ratio [OR], 1.63; 95% confidence interval [CI], 1.54-1.73) or are readmitted within 90 days (OR, 1.27; 95% CI, 1.20-1.34). After patient cohorts were matched, patients with myelopathy remained at elevated risk for reoperation at 2 years (OR, 1.55; 95% CI, 1.44-1.67) and postoperative dysphagia (2.78% vs. 1.68%, p <0.001) compared to patients without myelopathy.

CONCLUSIONS

We found inferior postoperative outcomes at baseline for patients with myelopathy undergoing ACDF compared to patients without myelopathy. Patients with myelopathy remained at significantly greater risk for reoperation and readmission after balancing potential confounding variables across cohorts, and these differences in outcomes were largely driven by patients with myelopathy undergoing 1-2 level fusions.

Cervical Myelopathy: Diagnosis, Contemporary Treatment, and Outcomes

Cervical myelopathy is a clinical syndrome caused by compression of the spinal cord between the levels of the C1 and T1 vertebrae. Its clinical presentation can mimic other degenerative and neurological pathologies, making diagnosis challenging. Diagnosis is confirmed with appropriate imaging studies carefully correlated with history and physical examination. Treatment options are focused on decompression of the spinal canal from an anterior, posterior, or combined anterior and posterior surgical approach depending on the location of compression and patient factors. Outcomes are favorable if treatment is performed prior to severe symptom onset.

IDENTIFICATION OF RISK FACTORS ASSOCIATED WITH 30-DAY READMISSION OF PATIENTS SUBMITTED TO ANTERIOR OR POSTERIOR ACCESS CERVICAL SPINE SURGERY

ABSTRACT Aim: To conduct a systematic review of the literature to identify risk factors associated with 30-day readmission of patients submitted to anterior or posterior access cervical spine surgery. Methods: The databases used to select the papers were PubMed, Web of Science, and Cochrane, using the following search strategy: patient AND readmission AND (30 day OR “thirty day” OR 30-day OR thirty-day) AND (spine AND cervical). Results: Initially, 179 papers that satisfied the established search stringwere selected. After reading the titles and abstracts, 46 were excluded from the sample for not effectively discussing the theme proposed for this review. Of the 133 remaining papers, 109 were also excluded after a detailed reading of their content, leaving 24 that were included in the sample for the meta-analysis. Conclusions: The average readmission rate in the studies evaluated was 4.85%. Only the occurrence of infections, as well as the presence of patients classified by the American Society of Anesthesiology (ASA) assessment system with scores greater than III, were causal factors that influenced the readmission of patients. No significant differences were noted when comparing the anterior and posterior surgical access routes. Level of evidence II; Systematic Review of Level II or Level I Studies with discrepant results.