Introduction: Perioperative acute kidney injury (AKI) can have serious outcomes, including postoperative wound infection, conversion to chronic renal failure, or even death. In the present study, patients aged ≥ 60 years who underwent lumbar single interbody fusion alone at our hospital were divided into two groups: those aged ≥ 80 years, and those aged 60-79 years. We then investigated whether the invasiveness of single lumbar interbody fusion was associated with perioperative renal function in these age groups.

Materials: A total of 77 patients who underwent lumbar single posterior lumbar intervertebral body fusion at L4/5 or L5/S level due to back pain, lower limb pain, and numbness were divided into those aged ≥ 80 years (n=x) and those aged 60-79 years (n=y). Serum total protein (TP), hemoglobin (Hb), creatinine phosphokinase (CPK), creatinine (CRE), and estimated glomerular filtration rate (eGFR) were evaluated preoperatively, the day after surgery, and 7 days after surgery. The rate of change in these parameters was investigated and compared between the two age groups for the presence of rhabdomyolysis associated with surgical invasion and AKI.

Results: Rhabdomyolysis was observed in two patients aged 60-79 years, but in none of those aged ≥ 80 years. Seven days after surgery, there were no cases with worsened renal function in the ≥ 80-year age group, but three cases in the 60-79-year age group. No cases of AKI occurred in either group.

Conclusions: Posterior lumbar interbody fusion can be performed relatively safely with regard to renal function, even in patients aged ≥ 80 years.

Introduction: Depending on the underlying cause, fusion may be used as the revision surgery technique following decompression surgery for lumbar canal stenosis or degenerative spondylolisthesis. Posterior lumbar interbody fusion was formerly the main surgical technique used, but oblique lateral interbody fusion (OLIF) is coming into use as a less invasive method. The advantage of OLIF is that it allows minimally invasive and indirect decompression without touching the previous operating field where adhesions and scarring are likely to have developed. In this study, the postoperative outcomes of OLIF were investigated to determine whether it is a suitable approach for revision surgery.

Methods: The study subjects were 16 patients (5 men and 11 women) aged 43-84 years (mean 71 years) at surgery and who underwent OLIF as revision surgery.

Results: The mean number of back surgeries prior to OLIF was 1.5 (range 1-7). Previous surgeries had been conducted at 10 different hospitals, including our own. The mean time from previous surgery to revision surgery was 5.8 years (range 5 months to 20 years). The number of intervertebral levels treated by OLIF was 1 (n=3 cases), 2 (n=8), and 3 (n=5). The mean operating time was 56 minutes per intervertebral level treated by OLIF, and 87 minutes for posterior pedicle screw (PPS) fusion.

Lower back and lower extremity pain disappeared immediately after surgery. The pre- and post-operative dural tube areas were compared in order to confirm the effectiveness of indirect decompression. The mean preoperative dural tube area was 101 mm², compared to a mean postoperative dural tube area of 155 mm².

Synostosis of the fused intervertebral levels was evaluated on coronal/sagittal computed tomography (CT) images and confirmed for all 34 intervertebral levels.

Discussion: OLIF allows indirect decompression without touching operating fields where adhesions may have developed, thus making it possible to carry out corrective fusion. However, further studies are required to determine the clinical outcomes from OLIF in situations such as operating fields with adhesions, or for hernia recurrence. The results of the present study indicate that OLIF was effective in revision surgery.

Conclusions: OLIF was performed as revision surgery following lumbar spinal decompression in 16 patients. This study demonstrated the effectiveness of indirect decompression.

Although surgery may be required to treat lumbar spinal stenosis associated with compression fractures, there are many reports of fixation surgery but few reports of decompression surgery alone. We investigated the characteristics of surgical cases of lumbar spinal stenosis associated with compression fractures in elderly patients aged > 75 years.

No apparent instability of the lumbar spine was encountered after surgery, and relatively good treatment results were obtained. Since is minimally invasive, it is worth considering for elderly patients who often have osteoporosis and other pre-existing diseases.

Introduction: Osteoporotic vertebral fractures (OVFs) are often associated with reduced activities of daily living (ADL). At our institute, OVF patients were hospitalized in an instant cast, kept on bed rest, and released from bed at a NRS of 3 or less. Here, we report on the results of this conservative treatment for OVFs.

Methods: A total of 42 patients (18 males and 24 females, mean age 83.0 years) admitted to our hospital with fresh OVF in June 2020 were included in this study. Image findings (X-ray, CT, MR, bone mineral density), the number of total vertebral fractures, duration of bed rest, and ADL before injury and at the last survey were evaluated as the non-union risk or severity of osteoporosis.

Results: CT revealed 8 cases of diffuse idiopathic skeletal hyperostosis, and 4 cases of posterior wall and pedicle fracture. MRI revealed 11 cases of T2 high signal localized sign, and 17 cases of T2 low signal extensive sign. Bone mineral density analysis revealed 15 cases of the lumbar spine and 21 cases of the femur with YAM <70%. The mean number of total vertebral fractures was 2.0, and the mean length of bed rest was 9.0 days. Significant differences were found between patients with and without risk of osteoporosis in terms of the sitting X-ray vertebral collapse rate, MRI signal changes, bone mineral density, and the total number of vertebral fractures. No significant difference was found in the number of patients who showed a decline in ADL to non-independent status at the end of follow-up.

Conclusions: From the perspective of preserving ADL, our conservative treatment of OVF is considered superior, since ADL declined to a non-independent status, even after approximately 9 days of bed rest.