Single-level Anterior Cervical Discectomy and Fusion Results in Lower Five-year Revisions than Posterior Cervical Foraminotomy in a Large National Cohort

Surgical site infection following isolated lumbar discectomy increases odds of revision lumbar surgery within first 6 months, but not beyond

BACKGROUND CONTEXT

Lumbar discectomy is a commonly performed surgery following which surgical site infection (SSI) may occur. Prior literature has suggested that, following SSI related to lumbar fusion, the rate of subsequent lumbar surgeries is increased over prolonged periods of time. This has not been studied specifically for lumbar discectomy.

PURPOSE

To define factors associated with SSI following lumbar discectomy and determine if subsequently matched cohorts with and without SSI have differential rates of subsequent lumbar surgery beyond irrigation and debridement (I&Ds) over time.

STUDY DESIGN/SETTING

Retrospective cohort study.

PATIENT SAMPLE

Adult patients undergoing isolated primary lumbar laminotomy/discectomy were identified from the 2010-2021 M157 PearlDiver database. Exclusion criteria included: age<18 years, preoperative diagnosis of infection, neoplastic, or traumatic diagnoses within 90 days prior to index surgery, additional spinal surgeries on the same day as lumbar discectomy, and not being active in the database for at least 90 days postoperative. From this study population, those who developed SSI were identified based on undergoing I&D within 90 days after surgery. Those with versus without SSI were then matched 1:4 based on age, sex, Elixhauser Comorbidity Index (ECI), and obesity.

OUTCOME MEASURES

Following initial I&D, incidence of revision lumbar surgery (revision lumbar discectomy, lumbar laminectomy, lumbar fusion) out to 5 years after lumbar discectomy.

METHODS

Following index isolated lumbar discectomy, those with versus without SSI requiring I&D were matched and compared for incidence of secondary surgery in defined time intervals (0-6 months, 6-12 months, 1-2 years, 2-5 years) using multivariable logistic regression, controlling for patient age, sex, ECI, and obesity status.

RESULTS

Of 323,025 isolated lumbar discectomy patients, SSI requiring I&D was identified for 583 (0.18%). Multivariable analysis revealed several independent predictors of these SSIs: younger age (odds ratio [OR] 0.85 per decade increase), ECI (OR 1.22 per 2-point increase), and obesity (OR 1.30). Following matching of those with versus without SSI requiring I&D, rates of subsequent surgery beyond I&D were compared. Those with SSI had significantly increased odds of lumbar revision in the first six months (OR 5.26, p<.001), but not 6-12 months (p=.462), 1-2 years (p=.515), or 2-5 years (p=.677).

CONCLUSIONS

Overall, SSI requiring I&D is a rare postoperative complication following lumbar discectomy. If occurring, subsequent surgery beyond I&D was higher in the first 6 months, but then not increased at subsequent time points out to five years.

Anterior cervical decompression and fusion at one and two levels: trends and factors associated with structural allograft versus synthetic cages

Background

Following decompression in anterior cervical discectomy and fusion (ACDF), reconstruction is typically done with structural allograft or a synthetic cage. Relative trends and factors associated with utilizing these implants have not been well characterized.

Methods

The PearlDiver 2011 to 2021 M157 database was used to identify adult patients undergoing 1- or 2-level ACDF. The incidence of structural allograft versus synthetic cage utilized was compared by year. Patient factors predictive of synthetic cage use as the structural interbody for ACDF were assessed with multivariable analysis. Further, the use of anterior plates was trended to provide a measure of usage of stand-alone devices (this comparison was made beginning with 2016 based on coding limitations).

Results

Of 173,833 isolated 1- or 2-level ACDF cases identified, structural allograft was used for 63,029 (36.3%) and synthetic cages were used for 110,804 (63.8%). The use of synthetic cages increased from 51.1% of cases in 2011 to 75.8% of cases in 2021 (p < 0.0001). Independent clinical predictors of synthetic cage use were: older age (odds ratio [OR] 1.02 per decade), female sex (OR 1.04), and greater ECI (OR 1.09 per 2-point increase).Independent non-clinical predictors of synthetic cage use were: geographic region (Northeast OR 1.11, South OR 1.85, and West 2.08, each relative to Midwest), and provider specialty (orthopedic OR 1.06 relative to neurosurgeons). There was an increase in the percent of synthetic cases without separately coded plate ("stand-alone" interbody cages: 21.7% in 2016 to 35.3% in 2021, p < 0.001).

Conclusions

The usage of synthetic cages in 1- and 2- level ACDF has increased relative to structural allograft between 2011 and 2021 in the United States and more recently the use of "stand-alone" synthetic cages has been on the rise. Non-clinical as well as clinical factors were associated with implant choice, suggesting room for more consistent care algorithms.

Femoral Head Core Decompressions: Characterization of Subsequent Conversion to Total Hip Arthroplasty and Related Complications

BACKGROUND

Core decompression is a minimally invasive joint-preserving approach for early-stage osteonecrosis. The rate at which core decompression patients require total hip arthroplasty (THA) and rates of perioperative adverse outcomes have not been well-characterized.

METHODS

Adult patients undergoing core decompression and/or THA with osteonecrosis of the femoral head were identified from the 2015 to 2021 Q3 PearlDiver M157 database. Those undergoing THA without or with antecedent core decompression were identified and matched 4:1 on age, sex, and Elixhauser Comorbidity Index. Postoperative 90-day adverse events were compared with multivariable analysis. Five-year rates of revision, dislocation, and periprosthetic fracture were compared by the Kaplan-Meier curve and log-rank tests.

RESULTS

Core decompressions were identified for 3,025 patients of whom 387 (12.8%) went on to THA within 5 years (64% within the first year). The median time from initial core decompression to THA was 252 days. For THA, 26,209 adults were identified and 387 had prior core decompression. After matching, there were 1,320 without core decompression and 339 with core decompression. No statistically significant differences were observed in 90-day postoperative adverse events or 5-year rates of revision, dislocation, or periprosthetic fracture.

CONCLUSION

Core decompression may be an option for patients with osteonecrosis and does not seem to affect THA outcomes if required later.

Biomechanical evaluation of the novel assembled internal fixed system in C2-C3 anterior cervical discectomy and fusion: a finite element analysis

BACKGROUND

To analyze and compare the biomechanical characteristics of the new combined cervical fusion device (NCCFD) and the traditional cage-plate construct (CPC) to ascertain its effectiveness in anterior cervical discectomy and fusion (ACDF) using finite element analysis.

METHODS

A finite element model of the cervical spine, inclusive of the occipital bone was created and validated. In the ACDF model, either CPC or NCCFD was implanted at the C2-C3 segment of the model. A pure moment of 1.0 Nm combined with a follower load of 50 N was directed onto the superior surfaces of the occipital bone to determine flexion, extension, lateral bending (left and right), and axial rotation (left and right). The range of motion (ROM), stress distribution at the bone-implant interface, and facet joint forces were investigated and compared between CPC and NCCFD systems.

RESULT

The results showed that the ROMs of the fused levels in both models were nearly zero, and the motions of the unfused segments were similar. In addition, the maximum displacement exhibited nearly identical values for both models. The maximum stress of NCCFD screws in lateral bending and rotational conditions is significantly higher than that of the CPC, while the NCCFD model's maximum stress remains within an acceptable range. Comparing the maximum fusion stress, it was found that the CPC experiences much lower fusion stress in anterior flexion and extension than the NCCFD, with no significant difference between the two in lateral bending and rotational states. Stress on the cage was mainly concentrated on both sides of the wings. Comparing the maximum IDP in the CPC and NCCFD, it was observed that maximum stresses rise in extension and lateral bending for both models. Lastly, stress distributions of the facet joints were generally similar across the two devices.

CONCLUSION

NCCFD not only provides the same level of biomechanical stability as CPC but also avoids postoperative complications associated with uneven force damage to the implant. The device offers a novel surgical alternative for ACDF in C2-C3 level.