Utility of Power Tool and Intraoperative Neuromonitoring for Percutaneous Pedicle Screw Placement in Single Position Surgery: A Technical Note

The Role of Cage Placement Angle in Optimizing Short-Term Clinical Outcomes in Lateral Lumbar Interbody Fusion

OBJECTIVE

The purpose is to investigate the impact of cage angle on clinical outcomes and indirect decompression efficacy in patients undergoing lateral lumbar interbody fusion (LLIF).

METHODS

A retrospective review was conducted on 87 patients with single-level lumbar degenerative disease who underwent LLIF. Patients were grouped based on the angle of cage placement: minimal (0°-5°), mild (>5° ≤ 15°), and severe (>15°). Clinical outcomes assessed included pain intensity, functional improvement, and complication rates. Magnetic resonance imaging evaluations included measurements of canal diameter and central canal area pre- and postoperatively. Patient-reported outcomes were also analyzed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire.

RESULTS

Clinical and radiographic outcomes were significantly improved across all cage angle groups. Reductions in low back pain, leg pain, and numbness were significant in all groups, with no significant differences. Magnetic resonance imaging evaluations revealed significant increases in canal diameter and central canal area postoperatively, confirming effective indirect decompression. Japanese Orthopedic Association Back Pain Evaluation Questionnaire scores showed significant improvements in all domains, including low back pain, lumbar function, walking ability, social life function, and mental health. However, the severe angle group had higher rates of delayed cage subsidence. Complications such as transient motor weakness, thigh pain, numbness, and the need for revision surgery were consistent across groups, with no significant differences.

CONCLUSIONS

LLIF effectively treats LDD patients, providing significant short-term clinical and radiographic improvements regardless of cage angle. However, oblique cage placement increases the risk of cage subsidence, requiring careful surgical planning and postoperative following.

Impact of Osteoporosis on Short-Term Surgical Outcomes in Lumbar Degenerative Disease Patients Undergoing Lateral Lumbar Interbody Fusion: A Retrospective Analysis

OBJECTIVE

This retrospective study assesses the influence of osteoporosis on the short-term clinical outcomes of lateral lumbar interbody fusion (LLIF) surgery in patients with lumbar degenerative diseases (LDDs), focusing on complications, pain intensity, and quality of life (QOL) improvements. The primary aim of this study is to investigate the impact of osteoporosis on the short-term clinical outcomes following LLIF surgery in LDD patients, with a particular focus on the incidence of cage subsidence (CS) and overall patient well-being postoperatively.

METHODS

A retrospective review was conducted on 73 patients who underwent LLIF for LDD. Patients were categorized into 2 groups based on osteoporosis status determined by dual-energy X-ray absorptiometry scans: those with osteoporosis (n = 20) and those without osteoporosis (n = 53). Data collection included demographics, surgical details, complications, magnetic resonance imaging analysis, pain intensity, and QOL (Japanese Orthopaedic Association Back Pain Evaluation Questionnaire).

RESULTS

The groups had no significant differences regarding operative time, estimated blood loss, and hospital stay duration. However, the incidence of CS was 40% in patients with osteoporosis, compared to 17% in nonosteoporotic patients. Despite this, significant improvements in spinal canal dimensions were observed in both groups. Both groups experienced significant reductions in pain intensity, with notable improvements in functional outcomes assessed by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, indicating the overall effectiveness of LLIF in enhancing patient well-being and functionality, irrespective of osteoporosis status.

CONCLUSIONS

Osteoporosis increases the risk of CS in LLIF surgery for LDD patients but does not affect short-term pain relief and QOL improvements.

Short-Term Comparison Between Unilateral Versus Bilateral Percutaneous Pedicle Screw Fixation in Short-Level Lateral Lumbar Interbody Fusion-A Prospective Randomized Study

STUDY DESIGN

Prospective randomized controlled trial.

OBJECTIVES

No prospective studies have directly compared clinical and radiographic outcomes of unilateral vs bilateral instrumented lateral lumbar interbody fusion (LLIF) for lumbar degenerative disease (LDD). We compared the short-term radiographic, clinical outcomes, and some complications of the unilateral percutaneous pedicle screw (PPS) (UPS) vs bilateral PPS (BPS) fixation in short-level spinal fusion with LLIF for LDD.

METHODS

This was a prospective randomized controlled study of 33 patients who underwent UPS or BPS fixation after LLIF for LDD; 18 patients were assigned to the UPS group and 15 patients to the BPS group. Clinical outcomes, complication rates, and fusion rates were assessed.

RESULTS

The two groups were similar in age, sex, preoperative diagnosis, and level of surgery. Blood loss, length of hospital stay, and numeric rating scale score one year after surgery did not differ between groups. The operative time was longer in the BPS than UPS group (120.2 vs 88.8 min, respectively; P = .029). Both groups showed improvement in disc height and dural sac in the immediate postoperative computed tomography and magnetic resonance imaging, which did not differ significantly between groups. The subsidence grade and fusion rate did not differ, but cage subsidence was more severe in the UPS than BPS group.

CONCLUSION

Unilateral and bilateral PPS fixation after LLIF yielded similar short-term clinical and radiological outcomes. However, severe cage subsidence was more common in the UPS group, which suggests that BPS fixation after LLIF may be a better choice over the long term.

Quantifying Satisfaction of Degenerative Lumbar Spinal Stenosis Patients in Post-lateral Lumbar Interbody Fusion Surgery: Establishing Critical JOABPEQ Cutoff Scores

OBJECTIVE

This retrospective study aimed to determine the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) cutoff scores for assessing patient satisfaction postlateral lumbar interbody fusion (LLIF) in degenerative lumbar spinal stenosis (DLSS) patients.

METHODS

Analyzing 136 DLSS patients (83 males, 53 females), the study evaluated demographics, pain (Numeric Rating Scale), and JOABPEQ outcomes (low back pain, lumbar function, walking ability, social life, mental health). Patient satisfaction was surveyed, and based on their responses, patients were categorized into "Beneficial" and "Nonbeneficial" groups. Statistical analysis encompassed the Kolmogorov-Smirnov test, t-tests, Mann-Whitney U test, and Receiver Operating Characteristic (ROC) curve analysis for JOABPEQ cutoff determination.

RESULTS

Postoperative improvements in JOABPEQ scores, especially in walking ability, social life function, and mental health, were significant. Pain intensity, assessed using the Numeric Rating Scale, also showed notable reductions. The Δ walking ability cutoff was set at 25.00, indicating substantial mobility improvement. This domain's area under the curve (AUC) was 0.815 (95% CI: 0.726-0.903), demonstrating high effectiveness in assessing patient satisfaction postsurgery. The study also found no significant differences in complication rates between groups for conditions like transient motor weakness, thigh pain/numbness, and revision surgery.

CONCLUSIONS

This study underscores the value of patient-centered outcomes in evaluating LLIF surgery success for DLSS. The identified JOABPEQ cutoff values provide a quantitative tool for assessing patient satisfaction, emphasizing the necessity of comprehensive postoperative evaluations beyond traditional clinical metrics for improved patient care and life quality.

Evaluating the Efficacy of IL-6 as Predictors of Lateral Lumbar Interbody Fusion Success: Insights From Pain Scores and JOABPEQ Assessments

STUDY DESIGN

A prospective study.

OBJECTIVES

This study aims to explore the correlation between interleukin (IL)- 6 levels in intervertebral disc (IVD) tissue and clinical outcomes in patients undergoing lumbar surgery for lumbar degenerative disease (LDD).

METHODS

This prospective study analyzed 32 patients (22 men and 10 women, average age 69.6 years) who underwent lateral lumbar interbody fusion (LLIF). IL-6 gene expression in IVD tissues collected during surgery was measured and correlated with pre- and postoperative clinical outcomes, including pain intensity assessed via Numeric Rating Scales (NRS) and quality of life (QOL) evaluated through the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ).

RESULTS

IL-6 levels showed statistical correlations with postoperative intensity of low back pain (LBP) and several JOABPEQ domains. Patients with higher expression of IL-6 levels experienced more severe postoperative LBP and lower scores in lumbar function, walking ability, social life function, and mental health. The effectiveness rate of JOABPEQ scores was exceptionally high for low back pain (.548), walking ability (.677), and social functioning (.563), demonstrating the effectiveness of LLIF. The average operation time was 105.6 minutes, and the estimated blood loss was 85.6 mL.

CONCLUSIONS

The study underscores IL-6 as a potential biomarker for predicting surgical outcomes in LDD. High IL-6 levels correlate with worse postoperative LBP and lower QOL scores. Integrating molecular markers like IL-6 with patient-reported outcomes could provide a more comprehensive approach to postoperative care in spinal disorders, aiming to improve the overall QOL for LDD patients undergoing LLIF surgery.

Minimally Invasive Approach for Degenerative Spondylolisthesis: Lateral Single-Position Surgery with Intraoperative Computed Tomography Navigation and Fluoroscopy: A Technical Note

OBJECTIVE

Degenerative spondylolisthesis (DS) is a prevalent condition that leads to low back pain and neurological symptoms. This technical note presents a novel surgical strategy for treating DS using lateral single-position surgery (SPS) in combination with intraoperative computed tomography navigation and fluoroscopy.

METHODS

Fifteen patients (5 males and 10 females, mean age 70.2 years) diagnosed with DS with a slip of 5 mm or more underwent lateral lumbar interbody fusion (LLIF) with percutaneous pedicle screw (PPS) fixation using this technique. The procedure involved slip reduction using an upside PPS and rod fixation, followed by LLIF performed in the same lateral position. The term "upside PPS" refers to a PPS that is inserted on the ceiling side of the patient's surgical field. Preoperative and postoperative radiographic assessments were conducted to evaluate the effectiveness of the lateral SPS.

RESULTS

The results demonstrated significant improvements in various parameters, including spondylolisthesis reduction, segmental lordosis, disc height, and spinal canal dimensions. The lateral-SPS procedure exhibited several advantages over traditional flip LLIF approaches for slip reduction. Additionally, the technique provided accurate intraoperative navigation guidance through computed tomography imaging, ensuring precise implant placement and slip reduction.

CONCLUSIONS

Combining LLIF and PPS fixation in a single procedure presents a precise, efficient approach for DS treatment, minimizing repositioning needs. This technique enables effective lumbar reconstruction, restoration of spinal stability, and improved patient outcomes. Although further investigation is warranted, lateral SPS surgery may hold promise as an innovative solution for managing DS by reducing surgical invasiveness and optimizing surgical efficiency.

Early Radiological Assessment of Static and Expandable Cages in Lateral Single Position for Indirect Decompression- Lateral Lumbar Interbody Fusion

OBJECTIVE

This study aimed to compare the postoperative alignment of static and expandable cages in lateral single-position (LSP) for indirect decompression in lateral lumbar interbody fusion (LLIF).

METHODS

We included sixty-seven patients who underwent LSP-LLIF for lumbar degenerative disease. We performed radiological assessments preoperatively and two weeks postoperatively using computed tomography and magnetic resonance imaging. We divided the patients into the expandable cage group (23 patients) and the static cage group (44 patients). We measured disc height (DH), segmental lordosis (SL), and foraminal area (FA) from computed tomography images and the area of the dural sac from magnetic resonance imaging. We recorded surgical outcomes and complications.

RESULTS

Both static and expandable cages demonstrated improvements in DH, SL, FA, and dural sac expansion. However, we found no statistically significant differences in the average change in DH (4.4 ± 2.1 mm vs. 4.2 ± 1.8 mm, P = 0.685), the average change in SL (1.0 ± 4.4° vs. 1.9 ± 3.6°, P = 0.310), or FA change (32.5 ± 31.7 mm2 vs. 34.9 ± 29.5 mm2, P = 0.966) between the expandable and static cage groups. We also found no statistically significant difference in dural sac enlargement between the two groups. We observed no significant differences in operation time, estimated blood loss, or length of hospital stay between the two groups. No severe adverse events or additional surgeries were reported.

CONCLUSIONS

In LSP-LLIF without facet joint resection or other posterior techniques, static and expandable cages showed comparable effectiveness in achieving increased DH, SL, FA, and indirect decompression.

Comprehensive Assessment of Indirect Decompression Through Lateral Lumbar Interbody Fusion for Degenerative Lumbar Spinal Stenosis: A Japanese Orthopedic Association Back Pain Evaluation Questionnaire-Based Analysis

STUDY DESIGN

A retrospective study.

OBJECTIVE

This study aimed to comprehensively evaluate the clinical outcomes of lateral lumbar interbody fusion (LLIF) as an indirect decompression technique for degenerative spondylolisthesis (DS) and concomitant degenerative lumbar spinal stenosis (DLSS) patients. We utilized the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) to assess treatment success and its impact on patient's quality of life (QOL).

METHODS

We included 124 patients who underwent LLIF. Pre- and postoperative JOABPEQ evaluations indicated treatment success. Subgroup analysis categorized patients' perceptions of surgery as beneficial or non-beneficial.

RESULTS

89% of patients (110/124) reported satisfaction with LLIF. Lateral lumbar interbody fusion achieved successful indirect decompression, increasing canal diameter and central canal area. Significant improvements occurred across all JOABPEQ domains, notably for low back pain, lumbar function, walking ability, social life function, and mental health. Patients who perceived the surgery as beneficial experienced fewer postoperative complications, lower numeric rating scale scores for pain relief, and greater functional outcome improvements compared to non-beneficial patients.

CONCLUSIONS

Our findings highlight the utility of JOABPEQ as a valuable and sensitive tool for assessing treatment effectiveness and patient-reported outcomes in DS and concomitant DLSS patients. Patients undergoing LLIF. The results affirm the favorable outcomes of LLIF as a surgical option for DLSS patients and emphasize the importance of considering patient perspectives when evaluating overall treatment success. The study provides valuable insights into the impact of indirect decompression on patients' QOL, supporting the effectiveness of LLIF as a minimally invasive technique for DLSS and DS management.

The Analysis of Preoperative Roussouly Classification on Pain Scores and Radiological Data in Lateral Lumbar Interbody Fusion for Patients with Lumbar Degenerative Disease

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

The type of sagittal profile defined by Roussouly has affected spinal degeneration and surgical outcome. This study aimed to investigate the effect of preoperative Roussouly classification on pain intensity and radiological data of patients with lumbar degenerative disease who underwent indirect decompression with lateral lumbar interbody fusion (LLIF).

METHODS

We retrospectively investigated 102 patients who underwent LLIF without direct decompression. Patients were subdivided into 4 groups according to the Roussouly classification determined from preoperative full-length and lateral spine X-rays, and classified according to Roussouly types I, II, and IV in the nonstandard group and Roussouly type III in the standard group.

RESULTS

The nonstandard group showed improved sagittal vertical axis and lumbar lordosis after LLIF surgery, but the midsagittal canal diameter and axial central canal area of the thecal sac using T2-weighted sagittal and axial magnetic resonance imaging were smaller than those in the standard group. On the other hand, each numeric rating scale score 1 year after surgery improved in all patients. Changes in numeric rating scale scores in low back pain, leg pain, and numbness were not statistically significant between Roussouly classification types.

CONCLUSIONS

These results suggest that the nonstandard group may have less indirect decompression effect from LLIF than the standard group. In the short term, we show for the first time after LLIF surgery that preoperative sagittal spinal alignment and the pelvic position may not significantly impact pain improvement.

The Effect of Preoperative Neuropathic Pain and Nociceptive Pain on Postoperative Pain Intensity in Patients with the Lumbar Degenerative Disease Following Lateral Lumbar Interbody Fusion

OBJECTIVE

The purpose of this study was to analyze whether the type of preoperative pain affects the improvement in postoperative pain intensity in patients with a lumbar degenerative disease (LDD).

METHODS

We retrospectively reviewed 93 patients who underwent lateral lumbar interbody fusion (LLIF) without direct decompression. All patients were evaluated using Numeric Rating Scale (NRS) scores for low back pain (NRS_LBP), leg pain (NRS_LP), and leg numbness (NRS_LN) and imaging data before and after LLIF surgery. Based on the Japanese version of the painDETECT scores, patients were classified into 3 groups: a neuropathic pain (NeP) group, a nociceptive pain (NocP) group, and an intermediate mixed pain group.

RESULTS

The Japanese version of the painDETECT identified NeP in 20.4% of patients with LDD prior to LLIF. Preoperative NRS_LBP, NRS_LP, and NRS_LN scores were higher in the NeP group than those in the NocP group. All types of pain improved after LLIF surgery. The NRS_LBP score 12 months after surgery was higher in the NeP group (3.8 ± 2.8) than that in the NocP group (1.9 ± 2.2) (P = 0.008). Similar results were obtained with NRS_LP (NeP group = 3.1 ± 2.8, NocP group = 1.5 ± 2.0, P = 0.010).

CONCLUSIONS

Although LLIF was useful for relieving all types of preoperative pain in LDD patients, the NRS scores for preoperative pain were higher in the NeP group than those in the NocP group, and the postoperative NRS_LBP and NRS_LP score was significantly higher in the NeP group. Thus, controlling preoperative NeP may improve therapeutic efficacy.

Comparative Study of Cage Subsidence in Single-Level Lateral Lumbar Interbody Fusion

We investigated the incidence and clinical features of cage subsidence after single-level lateral lumbar interbody fusion (LLIF). We studied a retrospective cohort of 59 patients (34 males, 25 females; mean age, 68.9 years) who received single-level LLIF. Patients were classified into subsidence and no-subsidence groups. Cage subsidence was defined as any violation of either endplate, classified using radiographs and computed tomography (CT) images. After one year, we compared patient characteristics, surgical parameters, radiological findings, pain scores, and fusion status. We also compared the Hounsfield unit (HU) endplate value obtained on CT preoperatively. Twenty patients (33.9%) had radiographic evidence of interbody cage subsidence. There were significant differences between the subsidence and no-subsidence groups in sex, cage height, fusion rate, and average HU value of both endplates (p < 0.05). There were no significant differences in age, height, weight, or body mass index. Moreover, there were no significant differences in global alignment and Numerical Rating Scale change in low back pain, leg pain, and numbness. Despite suggestions that patients with lower HU values might develop cage subsidence, our results showed that cage subsidence after single-level LLIF was not associated with low back pain, leg pain, or numbness one year post-operation.

Effects of preoperative sagittal spinal imbalance on pain after lateral lumbar interbody fusion

Sagittal misalignment has been associated with negative quality of life (QOL). However, there is no report on whether differences in preoperative sagittal misalignment in patients with lumbar degenerative diseases affect postoperative results after lateral lumbar interbody fusion (LLIF). We investigated whether preoperative sagittal alignment influences the correction of alignment after surgery and whether the preoperative sagittal alignment affects the rating of low back pain, leg pain, and leg numbness. The subjects were 81 patients (48 male, 33 females, average age at surgery 70.2 years) who underwent anterior-posterior combined surgery with LLIF and percutaneous pedicle screws from May 2018 to July 2020. Cluster analysis was performed using the preoperative sagittal vertical axis (SVA) value, and patients were classified into two groups (group 1; n = 30, SVA = 129.0 ± 53.4 mm, group 2; n = 51, SVA = 30.8 ± 23.5 mm). Baseline demographics and treatment data were compared between groups. Sagittal and pelvic parameters and pain scores, such as low back pain, leg pain, and leg numbness, were also compared. Operative time, blood loss, and length of hospital stay did not differ significantly between groups. The changes (Δ) in SVA and lumbar lordosis (LL) for all patients from before to after surgery were not significant (ΔSVA; p = 0.218, ΔLL; p = 0.189, respectively). The SVA, LL, and PI - LL changed significantly after the surgery in group 1, but no marked improvement in sagittal imbalance was obtained after LLIF surgery. The improvement in each pain score from before to after the surgery did not differ significantly between groups. LLIF surgery has a limited chance of recovering sagittal imbalance. However, postoperative low back pain, leg pain, and leg numbness may be improved by LLIF surgery, regardless of the preoperative sagittal alignment.