Factors of Adjacent Segment Disease Onset After Microsurgical Decompression for Lumbar Spinal Canal Stenosis

Comparison of short-segment and long-segment fixation in treatment of degenerative scoliosis and analysis of factors associated with adjacent spondylolisthesis

The bleeding time and amount in the short-segment group were shorter than in the long-segment group, and the bleeding volume was less than in the long-segment group. The Japanese Orthopaedic Association low back pain score, Oswestry Dysfunction Index, and lumbar spine stiffness disability index score of the two groups were significantly improved preoperatively, postoperatively, and at 6 months, 1 year, and 2 years post-operation. The differences were statistically significant at different time points within the groups. Neurological function improved to varying degrees postoperatively. The Cobb angle was significantly higher in both groups (P < 0.05). Adjacent vertebral disease occurred in 10 of 64 patients with short-segment fixation, with a prevalence of 15.6%. Preoperative pelvic tilt angle, preoperative pelvic projection angle (PPA), preoperative degree of matching of PPA to LL (PI-LL), and preoperative coronal Cobb angle were higher in patients with adjacent vertebral disease. There were varying degrees of improvement in low back pain and spinal function after short-segment decompression and fusion internal fixation. However, the patients are generally elderly and at risk of persistent low back pain and accelerated degeneration of adjacent segments.

Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically: an in silico study

BACKGROUND

The capsule of the zygapophyseal joint plays an important role in motion segmental stability maintenance. Iatrogenic capsule injury is a common phenomenon in posterior approach lumbar interbody fusion operations, but whether this procedure will cause a higher risk of adjacent segment degeneration acceleration biomechanically has yet to be identified.

METHODS

Posterior lumbar interbody fusion (PLIF) with different grades of iatrogenic capsule injury was simulated in our calibrated and validated numerical model. By adjusting the cross-sectional area of the capsule, different grades of capsule injury were simulated. The stress distribution on the cranial motion segment was computed under different loading conditions to judge the potential risk of adjacent segment degeneration acceleration.

RESULTS

Compared to the PLIF model with an intact capsule, a stepwise increase in the stress value on the cranial motion segment can be observed with a step decrease in capsule cross-sectional areas. Moreover, compared to the difference between models with intact and slightly injured capsules, the difference in stress values was more evident between models with slight and severe iatrogenic capsule injury.

CONCLUSION

Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically, and iatrogenic capsule damage on the cranial motion segment should be reduced to optimize patients' long-term prognosis.

Long-Term Changes in Sagittal Balance After Microsurgical Decompression of Lumbar Spinal Canal Stenosis in Elderly Patients: A Follow-Up Study for 5-Years After Surgery

OBJECTIVE

The purpose of this study is to investigate long-term changes in spinal sagittal balance after microsurgical decompression in lumbar canal stenosis (LCS).

METHODS

Fifty-two patients who underwent microsurgical decompression for symptomatic single level L4/5 spinal canal stenosis at our hospital were included in the study. All patients had standing full spine radiographs taken preoperatively, 1 year postoperatively, and 5 years postoperatively. Spinal parameters including sagittal balance were measured from the obtained images. First, preoperative parameters were compared with 50 age-matched asymptomatic volunteers. Next, the parameters before and after surgery were compared to examine long-term changes.

RESULTS

Sagittal vertical axis (SVA) was significantly increased in the LCS cases compared to the volunteers (P = 0.03). Postoperative lumbar lordosis (LL) was significantly increased (P = 0.03). Postoperative mean SVA decreased but the difference was not significant (P = 0.12). Although there was no correlation between preoperative parameters and the Japanese Orthopedic Association score, postoperative pelvic incidence (PI)-LL and pelvic tilt changes correlated with changes in Japanese Orthopedic Association score (PI-LL; P = 0.0001, pelvic tilt; P = 0.04). However, after 5 years of surgery, LL decreased and PI-LL increased (LL; P = 0.08, PI-LL; P = 0.03). Sagittal balance began to deteriorate but was not significant (P = 0.31). At 5 years postoperatively, 18 of 52 patients (34.6%) were found to have L3/4 adjacent segment disease. Cases with adjacent segment disease showed significantly worse SVA and PI-LL (SVA; P = 0.01, PI-LL; P < 0.01).

CONCLUSIONS

In LCS, lumbar kyphosis improves and sagittal balance tends to improve after microsurgical decompression. However, after 5 years, adjacent intervertebral degeneration occurs more frequently and sagittal balance begins to deteriorate in about one third of cases.

Risk of further surgery after decompression in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segments: focus on the number of residual lumbar/lumbosacral and sacroiliac mobile segments

PURPOSE

Patients with diffuse idiopathic skeletal hyperostosis (DISH) that extends to the lumbar segments (L-DISH) have a high risk of further surgery after lumbar decompression. However, few studies have focused on the ankylosis status of the residual caudal segments, including the sacroiliac joint (SIJ). We hypothesized that patients with more ankylosed segments beside the operated level, including the SIJ, would be at a higher risk of further surgery.

METHODS

A total of 79 patients with L-DISH who underwent decompression surgery for lumbar stenosis at a single academic institution between 2007 and 2021 were enrolled. The baseline demographics and radiological findings by CT imaging focusing on the ankylosing condition of the residual lumbar segments and SIJ were collected. Cox proportional hazard analysis was conducted to investigate the risk factors for further surgery after lumbar decompression.

RESULTS

The rate of further surgery was 37.9% during an average of 48.8 months of follow-up. Cox proportional hazard analysis demonstrated that the presence of fewer than three segments of non-operated mobile caudal segments was an independent predictor for further surgery (including both the same and adjacent levels) after lumbar decompression (adjusted hazard ratio 2.53, 95%CI [1.12-5.70]).

CONCLUSIONS

L-DISH patients with fewer than three mobile caudal segments besides index decompression levels are at a high risk of further surgery. Ankylosis status of the residual lumbar segments and SIJ should be thoroughly evaluated using CT during preoperative planning.

Application of Oblique Lateral Interbody Fusion Combined with Bridge-Locking Cage in Adjacent Segment Disease After Lumbar Fusion

OBJECTIVE

Adjacent segment disease (ASD) is considered any abnormal process that develops in the mobile segment next to spinal fusion, accompanied by related symptoms. To evaluate the efficacy and complications of oblique lateral interbody fusion (OLIF) combined with bridge-locking fusion on ASD after lumbar fusion.

METHODS

A total of 35 ASD patients who required re-operation after lumbar fusion in our hospital from March 2014 to March 2020 were retrospectively analyzed, among which 13 cases (seven males and six females; 62.3 ± 11.3 years old) received the treatment of OLIF + bridge-locking cage internal fixation (OLIF group), and 22 cases (14 males and eight females; 52.3 ± 17.8 years old) received the treatment of transforaminal lumbar interbody fusion (TLIF) + pedicle screw fixation (TLIF group). The comparison of the operation time, intraoperative blood loss, postoperative drainage volume, and length of hospital stay between the two groups of patients was performed using the t-test. The comparison of Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) at different time points before and after the operation was performed using analysis of variance for repeated measurement data. The fusion rate and postoperative complications of the two groups of patients were also evaluated.

RESULTS

The operation time of patients in the OLIF group (55.4 ± 12.4 min) was significantly shorter than that of patients in the TLIF group (94.3 ± 22.9 min) (P < 0.05), the length of stay of patients in the OLIF group (7.4 ± 2.3 day) was significantly shorter than that of patients in the TLIF group (12.4 ± 3.2 day) (P < 0.05); the intraoperative blood loss (62.2 ± 30.1 mL) and postoperative drainage (47.3 ± 22.4 mL) of patients in the OLIF group were significantly less than those of patients in the TLIF group with intraoperative blood loss (363.4 ± 120.2 mL) and postoperative drainage (285.5 ± 57.8 mL) (all Ps < 0.05). Besides, the VAS and ODI scores of the two groups of patients were improved 3 months after the operation and at the last follow-up (all Ps < 0.05). Three patients in the OLIF group developed complications such as hip flexion weakness and fusion cage sink, with an incidence of 23.1%. Three patients in the TLIF group developed complications including wound infection and intraoperative nerve injury, with an incidence of 22.7%.

CONCLUSION

The combination of OLIF and bridge-locking cage may be a safe and effective therapy for ASD patients after lumbar fusion operation.