Modified posterior lumbar interbody fusion using a single cage with unilateral pedicle screws: a retrospective clinical study

Trans-Pars Interarticularis Approach for Lumbar Interbody Fusion: An Efficient, Straightforward, and Minimally Invasive Surgery for Lumbar Spondylolisthesis and Stenosis

BACKGROUND

 Lumbar interbody fusion is a commonly applied surgical treatment for spondylolisthesis. For this procedure, various minimally invasive (MIS) approaches have been developed, including posterior lumbar interbody fusion, transforaminal lumbar interbody fusion (TLIF), oblique lumbar interbody fusion, and anterior lumbar interbody fusion. In this study, we characterized the features of an MIS trans-pars interarticularis lumbar interbody fusion (TPLIF) and compared its surgical outcomes with those of MIS-TLIF.

METHODS

 This study included 89 and 44 patients who had undergone MIS-TPLIF and MIS-TLIF, respectively, between September 2016 and December 2022. The following clinical outcomes were analyzed: operative time, blood loss, and hospitalization duration.

RESULTS

 The average operative time, blood loss, and hospitalization duration for the MIS-TPLIF and MIS-TLIF groups were, respectively, 98.28 and 191.15 minutes, 41.97 and 101.85 mL, and 5.8 and 6.9 days.

CONCLUSION

 The MIS-TPLIF approach for lumbar spondylolisthesis or other degenerative diseases involves the use of the commonly available and cost-effective instrument Taylor retractor, thus enabling posterior lumbar interbody fusion to be performed with minimal invasion. This approach also confers the benefits of a short learning curve and an intuitive approach. Our results suggest that although MIS-TPLIF is noninferior to MIS-TLIF, it is easier to learn and perform than MIS-TLIF.

Dislodgment Effects of Different Cage Arrangements in Posterior Lumbar Interbody Fusion: A Finite Element Study

The vertebral cage has been widely used in posterior lumbar interbody fusion. The risk of cage dislodgment is high for patients undergoing lumbar fusion surgery. Therefore, the main objective of this study was to use a lumbar fusion model to investigate the effects of cage dislodgment on different cage arrangements after PLIF. Finite element analysis was used to compare three PEEK cage placements, together with the fibula-type cage, with respect to the four kinds of lumbar movements. The results revealed that a horizontal cage arrangement could provide a better ability to resist cage dislodgment. Overall lumbar flexion movements were confirmed to produce a greater amount of cage slip than the other three lumbar movements. The lower part of the lumbar fusion segment could create a greater amount of cage dislodgment for all of the lumbar movements. Using an autograft with a fibula as a vertebral cage cannot effectively reduce cage dislodgment. Considering the maximum movement type in lumbar flexion, we suggest that a horizontal arrangement of the PEEK cage might be considered when a single PEEK cage is placed in the fusion segment, as doing so can effectively reduce the extent of cage dislodgment.

Clinical Efficacy and Rehabilitation of Microscopic "Over the Top" for Bilateral Decompression in Degenerative Lumbar Stenosis: A Retrospective Study

Background

Recently, “over the top” (also called ULBD; microscopic unilateral laminotomy for bilateral decompression) is a less invasive technique for symptomatic degenerative lumbar spinal stenosis (LSS), and this minimally invasive surgical technique has demonstrated favorable therapeutic outcomes. However, the risk of postoperative complications remains controversial.

Objective

This study is aimed at determining the clinical efficacy and complication and rehabilitation of the microscopic “over the top” for degenerative LSS in geriatric patients. Study Design. This was a retrospective study. Setting. All data were obtained from the People's Hospital of a University.

Methods

A retrospective analysis of 39 consecutive elderly patients treated for LSS by microscopic “over the top” between January 2016 and January 2018 was performed. A postoperative rehabilitation program for geriatric patients with restricted weight-bearing was instituted after the microscopic “over the top” treatment. Estimated blood loss, duration of operation, length of hospitalization, and total complications were also evaluated. The CT and MRI examinations of the lumbar spine were collected to evaluate the completeness of the nerve decompression. Clinical data were assessed at 6 months and 12 months after operation utilizing the visual analog scale (VAS), Oswestry Disability Index (ODI), and 36-Item Short-Form Health Survey (SF-36). Preoperative comorbidities, complications, and revision surgery were also recorded.

Results

We enrolled a total of 39 degenerative LSS patients (27 male and 12 female patients, mean age of 75.8 ± 9.2 years). Twenty patients had one-level of degenerative LSS; thirteen patients had two-level of LSS; six patients had three-level of LSS. The average follow-up time in our study was 14.6 ± 7.8 months (range, 6-24 months). The overall complication rate was 10.2% (4/39), and the reoperation rates at one year were 2.5% (1/39). VAS back and leg pain score at 6 months were decreased to 1.8 ± 0.7 and 1.4 ± 0.6, respectively, and remained at 1.9 ± 0.3 and 1.2 ± 0.2 at 12 months, respectively. ODI scores improved significantly from 32.26 ± 6.82 to 11.44 ± 2.50 at 6 months and 10.56 ± 2.29 at 12 months. 36-Item Short-Form Health Survey scores revealed a significant improvement throughout follow-up. Postoperative complications included dural tear (n = 2), neurologic deficit (n = 1), and reoperation (n = 1). No infections or hematomas were reported. Limitation. Multicenter research is recommended to confirm our results and investigate the factors related to clinical and radiographic results.

Conclusions

Microscopic “over the top” technique is a safe, effective option in the therapy of degenerative LSS and obtained satisfactory functional outcomes when coupled with aggressive rehabilitation, with a long recurrence-free recovery.

Biomechanical analysis of the posterior bony column of the lumbar spine

Background

Each part of the rear bone structure can become an anchor point for an attachment device. The objective of this study was to evaluate the stiffness and strength of different parts of the rear lumbar bone structure by axial compression damage experiments.

Methods

Five adult male lumbar bone structures from L2 to L5 were exposed. The superior and inferior articular processes, upper and lower edges of the lamina, and upper and lower edges of the spinous process were observed and isolated and then divided into six groups (n = 10). The specimens were placed between the compaction disc and the load platform in a universal testing machine, which was first preloaded to 5.0 N tension to eliminate water on the surface and then loaded to the specimen curve decline at a constant tension loading rate of 0.01 mm/s, until the specimens had been destroyed.

Results

Significant differences in mechanical properties were found among different parts of the rear lumbar bone structure. Compared with other parts, the lower edge of the lamina has good mechanical properties, which have a high modulus of elasticity; the superior and inferior articular processes have greater ultimate strength, which can withstand greater compressive loads; and the mechanical properties of the spinous process are poor, and it is significantly stiffer and weaker than the lamina and articular processes.

Conclusion

These data can be useful in future spinal biomechanics research leading to better biomechanical compatibility and provide theoretical references for spinal implant materials.

Effects of minimally invasive decompression surgery on quality of life in older patients with spinal stenosis

OBJECTIVES

Lumbar spinal stenosis (LSS) in the elderly may result in a progressive narrowing of the spinal canal leading to compression of nerve roots in some individuals. The aim of this study was to evaluate the quality of life changes after minimally invasive decompression surgery without instrumentation in geriatric patients with lumbar spinal stenosis.

PATIENTS AND METHODS

This prospective clinical study included 37 patients with American Society of Anesthesiologists (ASA) II-III scores between the ages of 65 and 86 years, who were planned to undergo surgical intervention due to LSS. All patients had neurogenic claudication and pain in the hips, thighs, and legs. Measurements of the osseous spinal canal were evaluated by magnetic resonance imaging. Before the surgical intervention, patient demographics and clinical characteristics were recorded. The Short-Form-36 test, the Oswestry Disability Index, and the Visual Analog Scale were applied to all patients preoperatively and two years postoperatively.

RESULTS

In the study population, 11 patients had single level of spinal stenosis, 20 patients had two levels of spinal stenosis, and six patients had three levels of spinal stenosis. There were significant differences between the preoperative and postoperative ODI and VAS scores. There was a statistically significant difference in all subscales of the SF-36 test with the exception of general health scores. Three patients who had dural damage during the operation were treated with bio glue. Also, no patients were recorded to have any neurological deficits and root injuries postoperatively.

CONCLUSION

Minimally invasive decompression surgery, without instrumentation, for lumbar spinal stenosis in geriatric patients significantly improves the patients' quality of life.