A novel lumbar total joint replacement may be an improvement over fusion for degenerative lumbar conditions: a comparative analysis of patient-reported outcomes at one year

Lumbar Disc Replacement Versus Interbody Fusion: Meta-analysis of Complications and Clinical Outcomes

Background

Lumbar spinal fusion is a commonly performed operation with relatively high complication and revision surgery rates. Lumbar disc replacement is less commonly performed but may have some benefits over spinal fusion. This meta-analysis aims to compare the outcomes of lumbar disc replacement (LDR) versus interbody fusion (IBF), assessing their comparative safety and effectiveness in treating lumbar DDD.

Methods

PubMed, Cochrane, and Google Scholar (pages 1-2) were searched up until February 2024. The studied outcomes included operative room (OR) time, estimated blood loss (EBL), length of hospital stay (LOS), complications, reoperations, Oswestry Disability Index (ODI), back pain, and leg pain.

Results

Ten studies were included in this meta-analysis, of which six were randomized controlled trials, three were retrospective studies, and one was a prospective study. A total of 1720 patients were included, with 1034 undergoing LDR and 686 undergoing IBF. No statistically significant differences were observed in OR time, EBL, or LOS between the LDR and IBF groups. The analysis also showed no significant differences in the rates of complications, reoperations, and leg pain between the two groups. However, the LDR group demonstrated a statistically significant reduction in mean back pain (p=0.04) compared to the IBF group.

Conclusion

Both LDR and IBF procedures offer similar results in managing CLBP, considering OR time, EBL, LOS, complication rates, reoperations, and leg pain, with slight superiority of back pain improvement in LDR. This study supports the use of both procedures in managing degenerative spinal disease.

In Vitro Wear of a Novel Vitamin E Crosslinked Polyethylene Lumbar Total Joint Replacement

BACKGROUND

A novel, lumbar total joint replacement (TJR) design has been developed to treat degeneration across all three columns of the lumbar spine (anterior, middle, and posterior columns). Thus far, there has been no in vitro studies that establish the preclinical safety profile of the vitamin E-stabilized highly crosslinked polyethylene (VE-HXLPE) lumbar TJR relative to historical lumbar anterior disc replacement for the known risks of wear and impingement faced by all motion preserving designs for the lumbar spine.

QUESTIONS/PURPOSE

In this study we asked, (1) what is the wear performance of the VE-HXLPE lumbar TJR under ideal, clean conditions? (2) Is the wear performance of VE-HXLPE in lumbar TJR sensitive to more aggressive, abrasive conditions? (3) How does the VE-HXLPE lumbar TJR perform under impingement conditions?

METHOD

A lumbar TJR with bilateral VE-HXLPE superior bearings and CoCr inferior bearings was evaluated under clean, impingement, and abrasive conditions. Clean and abrasive testing were guided by ISO 18192-1 and impingement was assessed as per ASTM F3295. For abrasive testing, CoCr components were scratched to simulate in vivo abrasion. The devices were tested for 10 million cycles (MC) under clean conditions, 5 MC under abrasion, and 1 MC under impingement.

RESULT

Wear rates under clean and abrasive conditions were 1.2 ± 0.5 and 1.1 ± 0.6 mg/MC, respectively. The VE-HXLPE components demonstrated evidence of burnishing and multidirectional microscratching consistent with microabrasive conditions with the cobalt chromium spherical counterfaces. Under impingement, the wear rates ranged between 1.7 ± 1.1 (smallest size) and 3.9 ± 1.1 mg/MC (largest size). No functional or mechanical failure was observed across any of the wear modes.

CONCLUSIONS

Overall, we found that that a VE-HXLPE-on-CoCr lumbar total joint replacement design met or exceeded the benchmarks established by traditional anterior disc replacements, with wear rates previously reported in the literature ranging between 1 and 15 mg/MC.

CLINICAL RELEVANCE

The potential clinical benefits of this novel TJR design, which avoids long-term facet complications through facet removal with a posterior approach, were found to be balanced by the in vitro tribological performance of the VE-HXLPE bearings. Our encouraging in vitro findings have supported initiating an FDA-regulated clinical trial for the design which is currently under way.

The Ideal Threshold of Hemoglobin A1C in Diabetic Patients Undergoing Elective Lumbar Decompression Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate the association of Hemoglobin A1C (HbA1c) with surgical site infection (SSI) and patient-reported outcomes (PROs), and to identify optimal HbA1c thresholds to minimize the risk of SSI and maximize PROs.

SUMMARY OF BACKGROUND DATA

Diabetes mellitus has been associated with worsened outcomes following spine surgery. HbA1c, a surrogate of glycemic control, is an important assessment tool in diabetic patients.

METHODS

A single-center, retrospective cohort study using prospectively collected data was undertaken. Diabetic patients undergoing elective lumbar decompression surgery between October 2010 and May 2021 were included. HbA1c, demographics, comorbidities, and perioperative data were collected. Primary outcomes included: 1) SSI, and 2) PROs, including the Numeric Rating Scale (NRS)-back/leg pain and Oswestry Disability Index (ODI). Secondary outcomes included: complications, readmissions, and reoperations within 90-days postoperatively. The minimum clinically important difference (MCID) was set at a 30% improvement from baseline PROs.

RESULTS

Of 1819 patients who underwent lumbar decompression surgery, 368 patients had diabetes mellitus, and 177 had a documented preoperative HbA1c value. Of patients with available HbA1c values, the mean age was 62.5±12.3, the mean HbA1c value was 7.2±1.5%, and SSI occurred in 3 (1.7%) patients only, which prevented further analysis of SSI and HbA1c. A significant association was seen with a higher HbA1c and failure to achieve NRS-Back pain MCID30 [Odds ratio(OR)=0.53, 95% confidence interval(CI) 0.42-0.78; P =0.001] and ODI MCID30 (OR=0.58, 95%CI 0.44-0.77; P =0.001), but not NRS-Leg pain MCID30 (OR=1.29, 95%CI 0.86-1.93; P =0.208). ROC-curve analysis and Youden's index revealed an HbA1c threshold of 7.8 for NRS-Back pain MCID30 (AUC=0.65, P <0.001) and 7.5 for ODI MCID30 (AUC=0.65, P =0.001).

CONCLUSIONS

In diabetic patients undergoing elective lumbar decompression surgery, HbA1c levels above 7.8 and 7.5 were associated with less improvement of NRS-Back and ODI scores at 12-months postoperatively, respectively. To optimize PROs, We recommend a preoperative HbA1c of 7.5 or below for diabetic patients undergoing elective lumbar decompression surgery.

Comparison of value per operative time between anterior lumbar interbody fusion and lumbar disc arthroplasty: A propensity score-matched analysis

Context

Despite the growing evidence demonstrating its effectiveness, lumbar disc arthroplasty (LDA) rates have not increased significantly in recent years. A likely contributing factor is uncertainties related to reimbursement and insurers' denial of coverage due to fear of late complications, reoperations, and unknown secondary costs. However, no prior study has compared the physician reimbursement rates of lumbar fusion and LDA.

Aim

The aim of this study was to compare the relative value units (RVUs) per min as well as 30-day readmission, reoperation, and morbidity rates between anterior lumbar interbody fusion (ALIF) and LDA.

Settings and Design

This was a retrospective cohort study.

Subjects and Methods

The current study utilizes data obtained from the National Surgical Quality Improvement Program database. Patients who underwent ALIF or LDA between 2011 and 2019 were included in the study.

Statistical Analysis Used

Propensity score matching analysis was performed according to demographic characteristics and comorbidities. Matched groups were compared through Fisher's exact test and independent t-test for categorical and continuous variables, respectively.

Results

Five hundred and two patients who underwent ALIF were matched with 591 patients who underwent LDA. Mean RVUs per min was significantly higher for ALIF compared to LDA. ALIF was associated with a significantly higher 30-day morbidity rate compared to LDA, while readmission and reoperation rates were statistically similar. ALIF was also associated with higher frequencies of deep venous thrombosis (DVT) and blood transfusions.

Conclusions

ALIF is associated with significantly higher RVUs per min compared to LDA. ALIF is also associated with higher rates of 30-day morbidity, DVT, and blood transfusions, while readmission and reoperation rates were statistically similar.

Optimal hemoglobin A1C target in diabetics undergoing elective cervical spine surgery

BACKGROUND CONTEXT

Diabetes mellitus (DM) is a well-established risk factor for suboptimal outcomes following cervical spine surgery. Hemoglobin A1C (HbA1c), a surrogate for long-term glycemic control, is a valuable assessment tool in diabetic patients.

PURPOSE

In patients undergoing elective cervical spine surgery, we sought to identify optimal HbA1c levels to: (1) maximize 1-year postoperative patient-reported outcomes (PROs), and (2) predict the occurrence of medical and surgical complications.

STUDY DESIGN/SETTING

A retrospective cohort study using prospectively collected data was performed in a single academic center.

PATIENT SAMPLE

Diabetic patients undergoing elective anterior cervical fusion and posterior cervical laminectomy and fusion (PCLF) between October 2010-March 2021 were included.

OUTCOME MEASURES

Primary outcomes included Numeric Rating Scale (NRS)-Neck pain, NRS-Arm pain, and Neck Disability Index (NDI). Secondary outcomes included surgical site infection (SSI), complications, readmissions, and reoperations within 90-days postoperatively.

METHODS

HbA1c, demographic, comorbidity, and perioperative variables were gathered in diabetic patients only. PROs were analyzed as continuous variables and minimum clinically difference (MCID) was set at 30% improvement from baseline.

RESULTS

Of 1992 registry patients undergoing cervical surgery, 408 diabetic patients underwent cervical fusion surgery. Anterior: A total of 259 diabetic patients underwent anterior cervical fusion, 141 of which had an available HbA1c level within one year prior to surgery. Mean age was 55.8±10.1, and mean HbA1c value was 7.2±1.4. HbA1c levels above 6.1 were associated with failure to achieve MCID for NDI (AUC=0.77, 95%CI 0.70-0.84, p<.001), and HbA1c levels above 6.8 may be associated with increased odds of reoperation (AUC=0.61, 95%CI 0.52-0.69, p=.078). Posterior: A total of 149 diabetic patients underwent PCLF, 65 of which had an available HbA1c level within 1 year. Mean age was 63.6±9.2, and mean HbA1c value was 7.2±1.5. Despite a low AUC for NRS-Arm pain and readmission, HbA1c levels above 6.8 may be associated with failure to achieve MCID for NRS-Arm pain (AUC=0.61, 95%CI 0.49-0.73, p=.094), and HbA1c levels above 7.6 may be associated with higher readmission rate (AUC=0.63, 95%CI 0.50-0.75, p=.185).

CONCLUSIONS

In a cohort of diabetic patients undergoing elective cervical spine surgery, HbA1c levels above 6.1 were associated with decreased odds of achieving MCID for NDI in anterior cervical fusion surgery. Though only moderate associations were seen for the select outcomes of reoperation (6.8), readmission (7.6), and MCID for NRS-Arm pain (6.8), preoperative optimization of HbA1c using these levels as benchmarks should be considered to reduce the risk of complications and maximize PROs for patients undergoing elective cervical spine surgery.

Barbed Suture versus Interrupted Suture in Posterior Cervical Spine Surgery: Are They Equivalent?

Introduction

Posterior cervical spine approaches have been associated with increased rates of wound complications compared to anterior approaches. While barbed suture wound closure for lumbar spine surgery has been shown to be safe and efficacious, there is no literature regarding its use in posterior cervical spine surgery. In a cohort of patients undergoing elective posterior cervical spine surgery, we sought to compare postoperative complication rates between barbed and traditional interrupted suture closure.

Methods

A retrospective review of demographics, past medical history, and operative and postoperative variables collected from a prospective registry between July 1, 2016, and June 30, 2020 was undertaken. All patients 18 years old and above undergoing elective posterior cervical fusion were included. The primary outcome of interest was wound complications, including surgical site infection (SSI), dehiscence, or hematoma. In addition, numerical rating scale (NRS) neck pain (NP), NRS arm pain (AP), Neck Disability Index (NDI), and operative time were collected. A variety of statistical tests were used to compare the two suture groups.

Results

Of 117 patients undergoing posterior cervical fusion, 89 (76%) were closed with interrupted suture and 28 (24%) with barbed suture. The interrupted cohort were more likely to have >1 comorbidity (p<0.001), diabetes mellitus (p=0.013), and coronary artery disease (p=0.002). No difference in postoperative wound complications between interrupted/barbed sutures was observed after univariate (OR 1.07, 95% CI: 0.27-4.25, p=0.927) and multivariable logistic regression analysis (OR 0.77, 95% CI: 0.15-4.00, p=0.756). Univariate logistic regression revealed no differences in achieving minimal clinically important difference (MCID) NRS-NP (OR 0.73, 95% CI: 0.28-1.88, p=0.508) or NRS-AP (OR 0.68, 95% CI: 0.25-1.90, p=0.464) at 3 months between suture groups. The interrupted suture group was less likely to achieve MCID NDI at 3 months (OR 0.29, 95% CI: 0.11-0.80, p=0.016).

Conclusions

Barbed suture closure in posterior cervical spine surgery does not lead to higher rates of postoperative wound complications/SSI compared to traditional interrupted fascial closure.

Is it Better to Stop at C2 or C3/4 in Elective Posterior Cervical Decompression and Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

(a) Compare operative variables, complications, and patient-reported outcomes (PROs) in patients with an upper instrumented vertebrae (UIV) of C2 versus C3/4, and (b) assess outcomes based on C2 screw type.

SUMMARY OF BACKGROUND DATA

When performing elective posterior cervical laminectomy and fusion (PCLF), spine surgeons must choose the upper instrumented vertebrae (UIV) at the subaxial cervical spine (C3/4) versus C2. Differences in long-term complications and PROs remain unknown.

METHODS

A single-institution, retrospective cohort study from a prospective registry was conducted. All patients undergoing elective, degenerative PCLF from December 2010 to June 2018 were included. Patients were divided into a UIV of C2 versus C3/4. Groups were 2:1 propensity matched for fusion extending to the thoracic spine. Demographics, operative, perioperative, complications, and 1-year PRO data were collected.

RESULTS

One hundred seventeen patients underwent elective PCLF and were successfully propensity matched (39 C2 vs. 78 C3/4). Groups were similar in fusion extending to the thoracic spine (P = 0.588). Expectedly, the C2 group had more levels fused (5.63 ± 1.89) compared with the C3/4 group (4.50 ± 0.91) (P = 0.001). The C2 group had significantly longer operative time (P < 0.001), yet no differences were seen in estimated blood loss (EBL) (P = 0.494) or length of stay (LOS) (P = 0.424). Both groups significantly improved all PROs at 1-year (EQ-5D; NRS-NP/AP; NDI). Both groups had the same percentage of surgical adverse events at 6.8% (P = 1.00). Between C2 screw type, no differences were seen in operative time, EBL, LOS, complications, or PROs.

CONCLUSION

In patients undergoing elective PCLF, those instrumented to C2 had only longer operative times compared with those stopping at C3/4. No differences were seen in EBL, LOS, 1-year PROs, and complications. Type of C2 screw had no impact on outcomes. Besides increased operative time, instrumenting to C2 had no detectable difference on surgical outcomes or adverse event rates.Level of Evidence: 3.