The anatomical relationship between the celiac artery and the median arch ligament in degenerative spinal surgery.

BACKGROUND: This study aimed to characterize the anatomical relationship between the spine, the celiac artery (CA), and the median arcuate ligament using preoperative contrast-enhanced computed tomography (CT) images of patients with spinal deformity who underwent surgical correction. METHODS: This retrospective study included 81 consecutive patients (34 males, 47 females; average age: 70.2 years). The spinal level at which the CA originated, the diameter, extent of stenosis, and calcification were determined using CT sagittal images. Patients were divided into two groups: CA stenosis group and non-stenosis group. Factors associated with stenosis were examined. RESULTS: CA stenosis was observed in 17 (21%) patients. CA stenosis group had significantly higher body mass index (24.9 ± 3.9 vs. 22.7 ± 3.7, p = 0.03). In the CA stenosis group, J-type CA (upward angling of the course by more than 90° immediately after descending) was more frequently observed (64.7% vs. 18.8%, p < 0.001). The CA stenosis group had lower pelvic tilt (18.6 ± 6.7 vs. 25.1 ± 9.9, p = 0.02) than non-stenosis group. CONCLUSIONS: High BMI, J-type, and shorter distance between CA and MAL were risk factors for CA stenosis in this study. Patients with high BMI undergoing fixation of multiple intervertebral corrective fusions at the thoracolumbar junction should undergo preoperative CT evaluation of the anatomy of CA to assess the poteitial risk of celiac artery compression syndrome.

Lateral Lumbar Interbody Fusion within Three-level for Patients with Neurological Symptoms due to Vertebral Fragility Fractures in the Lumbar Spine.

There is a lack of agreement on whether minimally invasive lateral lumbar intervertebral fusion (LLIF) is a suitable treatment option for vertebral fragility fractures (VFFs). Hence, we sought to evaluate the efficacy and safety of LLIF in the management of VFF with neurological deficits in the lumbar spine. Between April 2015 and March 2020, we conducted a retrospective observational study of patients with VFF treated with three-level or less LLIF. The participants had previously received conservative treatment but had not been able to control their neurological symptoms. To assess the outcomes of the LLIF procedures, the patients were followed up for a minimum of 1 year. Clinical and radiological results, which include the timing and location of the bony fusion, were analyzed. The study involved 19 patients with 23 vertebral fracture levels. The residual height of the fractured vertebra was found to be 57.0 ± 12.3% of the height of the adjacent level. The mean Japanese Orthopedic Association score significantly improved postoperatively. Postoperative radiological parameters were significantly maintained at 1 year, and lumbar lordosis was maintained at the last follow-up (45.0 ± 26.7). In total 31 LLIF levels, bone fusion was observed in four levels at 6 months postoperatively, in 16 levels at 1 year, and in 23 levels at the last follow-up. The facet joint had the highest bony fusion location. LLIF within three levels can be safely performed in certain VFF cases with sufficient residual vertebral height.

Anatomical Analysis of the Gonadal Veins and Spine in Lateral Lumbar Interbody Fusion.

BACKGROUND: The current study aimed to investigate the anatomical position of the gonadal veins (GVs) from the viewpoint of spine surgery and the risk factors associated with lateral lumbar interbody fusion (LLIF). METHODS: This retrospective study included 99 consecutive patients. The GV locations were divided into the ventral (V), dorsal medial (DM), and dorsal lateral (DL) sides based on lumbar disk levels on axial contrast-enhanced computed tomography images. The DM region surrounded by the vertebral body and psoas muscle had the highest risk of GV injury. The GV at each intervertebral disk level was examined in terms of laterality and sex. The patients were divided into group M (which included those with GV in the DM region at any vertebral level) and group O (which included those without GV in the DM region at any vertebral level). Then, the two groups were compared. RESULTS: In the case of lower lumbar levels and in women, the GVs were commonly observed in the DM region. Group M had a higher incidence of degenerative scoliosis than group O and a significantly larger Cobb angle. CONCLUSIONS: We should pay close attention to the GV location on the preoperative image when using LLIF, particularly in female patients with degenerative scoliosis.

Adjacent Segment Degeneration after Short-Segment Lateral Lumbar Interbody Fusion (LLIF).

Purpose: To investigate the influence on the adjacent segment degeneration (ASD) of short-segment lateral lumbar interbody fusion (LLIF) at 2 years postoperatively. Methods: Ninety-seven consecutive patients who underwent one- or two-level LLIF were included from two institutions. We diagnosed radiographical adjacent segment degeneration with the appearance of adjacent spondylolisthesis (>3 mm) or deterioration of adjacent disk height (>3 mm) on plain radiographs or decrease of the intervertebral angle (>5 degrees). The differences between the two groups with and without radiographical ASD were investigated using univariate and multivariate analyses to determine the risk factors for ASD. The variables included extent of adjacent decompression, posterior fixation method (open method or percutaneous method), and facet violation on postoperative CT. Results: In total, 19 patients (19.6%) were diagnosed as radiographical ASD 2 years after surgery. Univariate analysis showed that the ASD (+) group had a high frequency of adjacent decompression (21.1 vs. 3.8%, p = 0.035) compared with the ASD (-) group. There were no differences between the two groups in posterior fusion method (percutaneous method 42.1 vs. 57.7%, p = 0.221) or facet joint violation (15.8 vs. 14.1%, p = 0.860). The multivariate analysis found adjacent intervertebral decompression to be a risk factor for ASD 2 years after surgery (odds ratio: 9.95; 95% confidence interval: 1.2-82.1). Conclusions: Adjacent intervertebral decompression was considered to be a potential risk factor for the development of ASD after spinal fusion with LLIF.

Assessment of Ureters at Dangerous Locations in Lateral Lumbar Interbody Fusion.

INTRODUCTION: This study aimed to investigate the ureteral running position from the viewpoint of the spine, and to identify the spinal level and left-right difference in the ureter at a dangerous location of ureteral injury during surgery. METHODS: This retrospective study included 100 consecutive patients (39 males and 61 females; average age, 70.4 years). Preoperative contrast-enhanced computerized tomography (CT) scans obtained in the supine position for patients who underwent lateral lumbar interbody fusion (LLIF) were analyzed. The ureter location was divided into four regions on the axial CT images based on the lumbar disk levels as follows: A (ventral-medial), B (ventral-lateral), C (dorsal-medial), and D (dorsal-lateral). The C region surrounded by the vertebral body and the psoas muscle was assumed to have the highest probability of ureteral injury. We examined the characteristics of the ureteral position at each disc level. RESULTS: In the upper lumbar spine, the ureter was outside the lateral dorsoventral axis from the contact point of the psoas muscle, while in the lower lumbar spine, it was inside the axis. The ureters located in the C region increased significantly in the lower lumbar disk levels (L1-L2 and L2-L3: 0%; L3-L4: 5.5%; L4-L5: 14.8%; L5-S: 31.5%). Comparing the left and right sides, especially at L4-L5, the ureter in the C region was observed in 21% of all ureters on the left side and in 9% on the right side. With respect to gender differences, the ureters present in the C region were significantly more common in women at lumbar disk levels L3-L4, L4-L5, and L5-S. CONCLUSIONS: The ureters in the C region were common on the left side and at lower lumbar disk levels. To avoid ureteral injury, it is necessary to confirm the location of the ureter by using preoperative images and performing LLIF carefully.

Sacroiliac Joint Degeneration After Lumbopelvic Fixation.

STUDY DESIGN: Retrospective Study. OBJECTIVES: Sacroiliac buttress screws (SBS) and S2 alar iliac screws (SAI) are used as distal screws in cases with long fusion to the pelvis. Distal fixation ends, whether exceeding the sacroiliac joint (SIJ), may affect postoperative degenerative changes in the SIJ. The aim of this study was to investigate SIJ degeneration after lumbosacral and lumbopelvic fixation, using SBS and SAI in degenerative spine diseases, respectively. METHODS: This study included 70 patients aged ≥50 years with lumbosacral fusion (>3 levels). They were divided into 2 groups (SBS 20 and SAI 50 cases) based on the type of distal screws. Radiographical and clinical data were reviewed with a minimum 2-year follow-up. Radiographical SIJ degeneration was analyzed using computed tomography; clinical outcomes were evaluated using visual analog scale (VAS) and Japanese Orthopaedic Association Back Pain Questionnaire (JOABPEQ). RESULTS: No significant differences were observed in patients' preoperative characteristics between the 2 groups. The incidence of SIJ degeneration, including osteophyte formation (30.0% and 8.0%, p = 0.03), intraarticular air (75.0% and 16.0%, p < 0.001), and subchondral cyst (20.0% and 2.0%. p = 0.02) in SBS and SAI groups, respectively, at the follow-up, was significantly higher in the SBS group. Although SIJ degenerative changes were significantly different between the SBS and SAI groups, there was no significant difference in VAS and JOABPEQ scores between the groups at 2 years post-surgery. CONCLUSIONS: Lumbosacral fusion can cause SIJ degeneration, which is more frequent when SBS are used in fixation to the sacrum.

Comparison of Outcomes between Minimally Invasive Lateral Approach Vertebral Reconstruction Using a Rectangular Footplate Cage and Conventional Procedure Using a Cylindrical Footplate Cage for Osteoporotic Vertebral Fracture.

The aim of the current study was to compare outcomes between lateral access vertebral reconstruction (LAVR) using a rectangular footplate cage and the conventional procedure using a cylindrical footplate cage in patients with osteoporotic vertebral fracture (OVF). We included 46 patients who underwent anterior-posterior combined surgery for OVF: 24 patients underwent LAVR (Group L) and 22 underwent the conventional procedure (Group C). Preoperative, postoperative, and 1- and 2-year follow-up X-ray images were used to measure local lordotic angle, correction loss, and cage subsidence (>2 mm in vertebral endplate depression). In anterior surgery, the operation time was significantly shorter (183 vs. 248 min, p < 0.001) and the blood loss was significantly less (148 vs. 406 mL, p = 0.01) in Group L than in Group C. In Group C, two patients had anterior instrumentation failure. Correction loss was significantly smaller in Group L than in Group C (1.9° vs. 4.9° at 1 year, p = 0.02; 2.5° vs. 6.5° at 2 years, p = 0.04, respectively). Cage subsidence was significantly less in Group L than in Group C (29% vs. 80%, p < 0.001). LAVR using a rectangular footplate cage is an effective treatment for OVF to minimize surgical invasiveness and postoperative correction loss.

Transdiaphragmatic Approach as a Novel Less Invasive Retroperitoneal Approach at Thoracolumbar Junction: Comparison with Conventional Diaphragmatic Incision.

INTRODUCTION: Lateral corpectomy has been considered a minimally invasive surgery, allowing a "transdiaphragmatic approach" at the thoracolumbar junction. This approach allows for a small diaphragmatic incision directly in the retroperitoneal space and the affected vertebra. However, its effectiveness in comparison to a conventional approach remains unclear. Thus, in this present study, we compared the surgical outcomes between conventional diaphragmatic detachment and the transdiaphragmatic approach in patients with vertebral fracture at the thoracolumbar junction. METHODS: In total, 31 patients with a vertebral fracture at the thoracolumbar junction (T12-L2) were included in this study: 17 underwent a conventional approach, whereas 14 underwent a transdiaphragmatic approach, with a minimum 2-year follow-up. The effectiveness of surgery was evaluated in each category of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). RESULTS: Operative time and estimated blood loss were determined to be significantly shorter in the transdiaphragmatic than in the conventional approach. Perioperative complications were observed in the conventional approach (one atelectasis and one pleural effusion), while no complication was noted in the transdiaphragmatic approach. There were no significant differences in postoperative quality of life as assessed by JOABPEQ in terms of pain-related disorders, lumbar spine dysfunction, gait disturbance, social life dysfunction, or psychological disorders between the conventional and transdiaphragmatic approaches. CONCLUSIONS: A "transdiaphragmatic approach" using lateral access surgery has been found to be associated with a shorter operative time and less blood loss with fewer complications than the conventional approach. Given that equivalent clinical outcomes were achieved in both conventional and transdiaphragmatic approaches, this "transdiaphragmatic approach" could be useful because of its minimal invasiveness.

Pedicle screw placement with use of a navigated surgical drill at subaxial cervical spine.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: This study was performed to evaluate the accuracy of cervical pedicle screw (CPS) placement with use of a navigated surgical drill (ND) and to compare it with navigated manual probe (MP) at C3-C6. METHODS: 47 consecutive patients (27 males and 20 females, 67.2 [33-91] years) underwent a posterior cervical fixation using CPSs under an intraoperative 3D - - CT based navigation system (total 207 CPSs). For initial probing, ND with 2.2-mm steel burr was used since Apr. 2017 (Group ND; 33 patients, 152 CPSs). MP was used earlier (Group MP; 14 patients, 55 CPSs). There were no other different procedures between the two groups. The accuracy of CPS placement was graded with postoperative CT and compared between the two groups. RESULTS: There were no significant differences in the total perforation rates both in axial and sagittal planes between Groups ND and MP (axial; 7.2% vs. 14.5%, p = 0.25, sagittal; 10.5% vs. 14.5%, p = 0.46). However, the lateral and rostral perforation rates were significantly reduced in Group ND compared to Group MP (lateral: 36.4% vs. 87.5%, p = 0.04; rostral: 6.3% vs. 100%, p = 0.001). CONCLUSION: Although ND did not decrease the total perforation rate significantly, it reduced the incidence of lateral and rostral perforation. ND is likely to make initial probing easier without a forcible manipulation which might cause vertebral rotation.

True accuracy of percutaneous pedicle screw placement in thoracic and lumbar spinal fixation with a CT-based navigation system: Intraoperative and postoperative assessment of 763 percutaneous pedicle screws.

PURPOSE: To investigate intraoperative reinsertion of percutaneous pedicle screw (PPS) with intraoperative CT-based navigation and to evaluate the rate of deviation of PPS at postoperative radiographic examination. METHODS: Seven hundred sixty-three screws were inserted in 138 patients. We investigated the rate of occurrence of intraoperative PPS reinsertion after the diagnosis of screw deviation by fluoroscopy and the causes of each screw deviation. The subsequent distribution of PPS deviation was evaluated by postoperative CT. We also assess the difference in variance between the group judged to be PPS misplaced intra-/postoperatively (IOD group/POD group) and appropriate PPS placement (ND group). RESULTS: Among all the screws inserted, 10 (1.3%) were diagnosed as being deviated by fluoroscopy during surgery, and 74 (9.7%) screws were found to be deviated at postoperative CT evaluation. We found more pedicle screw mismatch in the POD group than in the ND group (52.7 vs 11.0%, P < 0.001). The distance between the screw and the reference was greater in the IOD group than that in the ND group (1.4 ± 1.2 vs 2.4 ± 1.1 vertebral levels, P = 0.016). In one patient in the IOD group, a motor function deficit was observed postoperatively. CONCLUSION: PPS fixation under intraoperative CT-based navigation did not prevent screw deviation completely. It is necessary to consider errors that occur during surgery and to confirm placement with real-time assistance such as fluoroscopy even in a surgery performed under CT navigation assistance.

Reoperation for Late Neurological Deterioration After Laminoplasty in Individuals With Degenerative Cervical Myelopathy: Comparison of Cases of Cervical Spondylosis and Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of this study was to elucidate the rate and causes of reoperation for late neurological deterioration after cervical laminoplasty by comparing cases of cervical spondylotic myelopathy (CSM) with those of ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: Although the long-term surgical outcomes of cervical laminoplasty in patients with CSM or OPLL are satisfactory, reoperation is sometimes required for late neurological deterioration after laminoplasty. However, limited information is available about long-term follow-up in such cases. METHODS: This retrospective cohort study included 623 patients who underwent cervical laminoplasty for cervical myelopathy (average follow-up duration, 6.1 [range, 2-15] years). The rate of reoperations for late neurological deterioration (>6 mo after the initial surgery) was investigated. RESULTS: Primary diagnoses were CSM and OPLL in 522 (83.8%) and 101 (16.2%) patients, respectively. During the follow-up period, 10 (1.6%) patients required reoperation: 7 (1.3%) in the CSM group and 3 (3.0%) in the OPLL group. No significant difference was found between the CSM and OPLL groups regarding patients requiring reoperation (P = 0.26). The mean elapsed time between primary surgery and reoperation was 4.7 ±â€Š3.2 and 10.0 ±â€Š5.7 years in the CSM and OPLL groups, respectively. The predicted risk percentages of reoperation at 10 years after primary surgery were 2.9% and 1.0% in the CSM and OPLL group, respectively. The causes of reoperation for CSM were C5 palsy in five, severe radiculopathy in one, and restenosis due to instability after laminoplasty in one case; the cause of reoperation for OPLL was enlargement of ossification in all three cases. CONCLUSION: Although the clinical outcomes of laminoplasty were favorable in most patients, reoperation for late neurological deterioration was required in approximately 1.0% to 3.0% of CSM and OPLL cases within 10 years after laminoplasty. LEVEL OF EVIDENCE: 4.

Simultaneous single-position lateral interbody fusion and percutaneous pedicle screw fixation using O-arm-based navigation reduces the occupancy time of the operating room.

PURPOSE: Lateral interbody fusion and posterior percutaneous pedicle screw (LIF-PPS) fixation has been performed in two-stage positioning. The aim of this study was to investigate the surgical outcomes of simultaneous single-position LIF-PPS fixation using O-arm-based navigation. METHODS: Overall, 102 consecutive subjects underwent indirect decompression surgery for spondylolisthesis with LIF-PPS fixation. Fifty-one subjects underwent surgery with repositioning, and 51 in the right lateral decubitus position. We compared these two groups in terms of the surgery time, occupancy time in the operating room, intraoperative blood loss, Japanese Orthopaedic Association (JOA) score, local lordosis acquisition in postoperative radiographs, and accuracy of screw insertion using postoperative CT scans. RESULTS: In the single-position group, surgery time, occupancy time of the operating room, and estimated blood loss were 93.3 ± 19.3 min (vs. the repositioning group: 121.0 ± 37.1 min; p < 0.001), 176.3 ± 36.4 min (vs. 272.4 ± 42.7 min; p < 0.001), and 93.4 ± 78.8 ml (vs. 40.9 ± 28.7 ml; p < 0.001), respectively. The JOA scores (pre-/postoperative) were 15.1 ± 3.0/24.4 ± 2.8 (p < 0.001) for the single-position group and 15.1 ± 4.0/24.8 ± 3.0 (p < 0.001) for the repositioning group. The rate of misplacement was 1.8% versus 4.0%, respectively (p = 0.267), and the lordosis acquisition was 4.2° ± 4.1° versus 4.4° ± 3.2°, respectively (p = 0.516). CONCLUSIONS: Single-position surgery exhibited comparable clinical outcomes and local lordosis acquisition with conventional repositioning LIF-PPS fixation. This single-position minimally invasive technique reduces the occupancy time of the operating room and workforce requirements. These slides can be retrieved under Electronic Supplementary Material.

Patient-reported Quality of Life Following Posterior Lumbar Interbody Fusion or Indirect Decompression Using Lateral Lumbar Interbody Fusion.

STUDY DESIGN: A retrospective review of prospectively collected data. OBJECTIVE: The aim of this study was to compare quality of life (QOL) outcomes of posterior lumbar interbody fusion (PLIF) with lateral lumbar interbody fusion (LLIF) using reports from patients obtained at the 2-year postoperative follow-up. SUMMARY OF BACKGROUND DATA: Indirect decompression with LLIF is used to treat degenerative lumbar diseases that require neural decompression. However, the difference in improvement in QOL following indirect decompression compared with direct neural decompression using PLIF is unclear. METHODS: We enrolled 284 consecutive patients with degenerative lumbar spondylolisthesis in the present study, 203 who underwent PLIF and 81 who underwent LLIF. All patients completed a minimum of 2 years of follow-up. We evaluated the effectiveness of surgery in each category of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). RESULTS: The results of preoperative JOABPEQ and the severity of thecal sac stenosis were not significantly different between PLIF and LLIF, neither was the rate of perioperative complications (14.8% and 15.4% for the PLIF and LLIF groups, respectively; P = 0.91). The effectiveness at 2 years postoperatively was almost the same for all five domains of the JOABPEQ: 62.6% and 68.9% for pain-related disorders (P = 0.34), 38.3% and 42.7% for lumbar spine dysfunction (P = 0.51), 65.8% and 67.5% for gait disturbance (P = 0.79), 53.5% and 48.8% for social life dysfunction (P = 0.47), and 29.1% and 33.3% for psychological disorders (P = 0.48) following PLIF and LLIF, respectively. Visual analogue scale results for back and lower-limb pain and numbness of the lower limbs were almost the same for both groups. No significant differences were observed in terms of perioperative complications and radiographical outcomes. CONCLUSION: Indirect decompression using LLIF improves QOL and radiographical outcomes to a comparable degree as direct decompression via PLIF. LEVEL OF EVIDENCE: 4.

Lateral approach corpectomy and reconstruction after anterior longitudinal ligament release in cases with fixed kyphosis: A technical note and a preliminary case series.

Lateral approach corpectomy is a useful surgical technique for adult spinal deformity with vertebral deformity. However, in cases with anterior ankylosing over adjacent vertebrae, it is hard to achieve ideal correction without posterior column resection. To minimize surgical invasiveness, we have developed a method for lateral approach corpectomy and reconstruction after anterior longitudinal ligament release (LCRA) in such cases. The aim of the current study is to describe LCRA, and investigate surgical invasiveness, sagittal correction and perioperative complications in this surgery. The subjects were three patients (all female, average age 69.0 years old) with adult spinal deformity with severe fixed kyphosis who underwent LCRA and posterior fixation with pedicle screws. The primary disease was osteoporotic vertebral fracture in all patients. The operative levels were T12 in 2 cases and L2 in 1 case. The operative time and estimated blood loss were 442.3 ± 51.9 min and 875.7 ± 397.5 mL, respectively. Local kyphotic deformity was well corrected from 54.2 ± 4.3° preoperatively to 10.1 ± 3.7° in these surgeries (p < 0.001). There were surgical complications of dural tear and postoperative hemothorax in one case each. These outcomes suggest that LCRA gives good sagittal correction in cases with fixed kyphosis after osteoporotic vertebral fracture, and that this method is a viable surgical option for correction of fixed kyphosis.

Indirect Decompression Using Lateral Lumbar Interbody Fusion for Restenosis after an Initial Decompression Surgery.

STUDY DESIGN: Retrospective comparative study. PURPOSE: We compared clinical and radiographical outcomes after lumbar decompression revision surgery for restenosis by lateral lumbar interbody fusion (LLIF) and posterior lumbar interbody fusion (PLIF). OVERVIEW OF LITERATURE: Indirect lumbar decompression with LLIF was used to treat degenerative lumbar diseases requiring neural decompression. However, only a few studies have focused on the effectiveness of this technique for restenosis after lumbar decompression. METHODS: We retrospectively investigated 52 cases involving lumbar interbody fusions for restenosis with spondylolisthesis after lumbar decompressions; these cases consisted of 15 patients who underwent indirect decompression with LLIF and posterior fixation and 37 patients who underwent the same procedure with PLIF. We compared Japanese Orthopaedic Association (JOA) scores and perioperative complications between groups. The cross-sectional areas of the thecal sac on magnetic resonance imaging were measured before, immediately after, and 2 years after surgery. We conducted statistical analyses using unpaired t -test and Fisher's exact tests, and a p -value <0.05 was considered statistically significant. RESULTS: The operative time was significantly shorter in the LLIF group than in the PLIF group (115.3±33.6 min vs. 186.2±34.2 min, respectively; p <0.001). In addition, the intraoperative blood loss was significantly lower in the LLIF group than in the PLIF group (58.2±32.7 mL vs. 303.2±140.1 mL, respectively; p <0.001). We found two cases of transient lateral thigh weakness (13.3%) in the LLIF group and five cases of incidental durotomy, one case of deep infection, and one case of neurological deterioration in the PLIF group-resulting in a higher complication incidence (18.9%), although it did not reach (p =0.63). The JOA scores improved significantly in both groups. CONCLUSIONS: Indirect decompression using LLIF provided acceptable clinical and radiographical outcomes in patients with restenosis with spondylolisthesis after lumbar decompression; no revision-surgery-specific complications were found. Our results suggest that LLIF is a safe and minimally invasive procedure for revision surgery.

Neurological function following early versus delayed decompression surgery for drop foot caused by lumbar degenerative diseases.

The purpose of this study was to investigate the effectiveness of early (<72 h) versus late (≥72 h) decompression surgery after the onset of drop foot caused by root disorder in lumbar degenerative diseases (LDDs). Data were included from 60 patients who underwent decompression surgery for drop foot caused by LDDs, including lumbar disk herniation or lumbar spinal stenosis. The primary outcome was ordinal change in the manual muscle test (MMT) at 2 years follow-up. Secondary outcomes included changes in the Japanese Orthopedic Association's (JOA) score. The early- and late-stage surgery groups included 20 and 40 patients with mean durations from the onset of drop foot to operation of 0.8 days (range, 0-3 days) and 117.1 days (range, 10-891 days), respectively. There was no significant difference (p = 0.33) between the early- and late-stage surgery groups in the improvement of MMT scores to >4 (90% versus 80%, respectively). However, more patients in the early-stage group achieved an MMT score >5 compared with those in the late-stage surgery group (80% versus 45%; p = 0.03). Furthermore, the recovery rate of JOA scores was significantly higher in the early-stage (89.1%) compared with the late-stage surgery group (68.6%; p < 0.001). Early decompression surgery produced better neurological recovery; however, an improvement of >4 in the MMT score was achieved in 80% of cases with late decompression.

The Prevalence and Risk Factors for S2 Alar-Iliac Screw Loosening with a Minimum 2-Year Follow-up.

STUDY DESIGN: A retrospective cohort study. PURPOSE: The purpose of this study was to investigate the prevalence and risk factors for S2 alar-iliac (SAI) screw loosening following lumbosacral fixation, with a minimum 2-year follow-up. OVERVIEW OF LITERATURE: Although SAI screws allow surgeons to perform lumbosacral fixation with a low profile and enhanced biomechanical strength, screw loosening following surgery can occur in some cases. However, few studies have investigated the prevalence and risk factors for SAI screw loosening. METHODS: This retrospective study included 35 patients (mean age, 72.8±8.0 years; male, 10; female, 25) who underwent lumbosacral fixation using SAI screws with at least 2 years of follow-up. SAI screw loosening and L5-S bony fusion were assessed using computed tomography. The period for which the screws appeared loose and the risk factors for SAI screw loosening were investigated 2 years after surgery. RESULTS: A total of 70 SAI screws and 70 S1 pedicle screws were inserted. Loosening was observed 0.5, 1, and 2 years after surgery in 17 (24.3%), 35 (50.0%), and 35 (50.0%) SAI screws, respectively. Bony fusion rate at L5-S was significantly lower in patients with SAI screw loosening than in those without screw loosening (65.0% vs. 93.3%, p =0.048). The score for SAI screw contact with the iliac cortical bone and the bony fusion rate at L5-S were significantly lower in the loosening group than in the non-loosening group (1.8±0.5 vs. 2.2±0.3, p <0.001, respectively). Postoperative pelvic incidence-lumbar lordosis was significantly higher in the loosening group than in the non-loosening group (7.9°±15.4° vs. 0.5°±8.7°, p =0.02, respectively). CONCLUSIONS: SAI screw loosening is closely correlated with pseudoarthrosis at L5-S. Appropriate screw insertion and optimal lumbar lordosis restoration are important to prevent postoperative complications related to SAI screws.

Indirect Decompression on MRI Chronologically Progresses After Immediate Postlateral Lumbar Interbody Fusion: The Results From a Minimum of 2 Years Follow-Up.

MINI: On magnetic resonance imaging, indirect decompression using lateral lumbar interbody fusion and posterior fixation was confirmed immediately after surgery and also continuously progressed after surgery, particularly during the first 6 months. Thecal sac enlargement was also confirmed, and is suspected to be caused by the atrophy of the ligamentum flavum and the disc. STUDY DESIGN: A prospective cohort study. OBJECTIVE: The aim of this study was to investigate radiographical changes related to indirect decompression using lateral lumbar interbody fusion (LLIF) with posterior fixation. SUMMARY OF BACKGROUND DATA: Indirect lumbar decompression via LLIF is used to treat degenerative lumbar diseases requiring neural decompression. Although evidence suggests that thecal sac enlargement follows shortly after surgery, few studies have described the postoperative changes on MRIs. METHODS: This study involved 102 patients who underwent indirect decompression at 136 levels, with LLIF and posterior fixation. Magnetic resonance imaging (MRIs) were collected preoperatively and several times postoperatively (over a 2-year period starting immediately after surgery). We then quantified the cross-sectional areas of the thecal sac and ligamentum flavum, as well as the anteroposterior diameter of disc bulging, and qualitatively assessed lumbar spinal stenosis according to a modified version of Schizas' classification [Grades A (mild) to C (severe)]. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for the assessment of the clinical symptoms. RESULTS: All changes were observable immediately after surgery, progressed over time, and were significantly different statistically at 2 years after surgery. The thecal sac was significantly larger (189% of preoperative; P < 0.0001), while the ligamentum flavum and disc bulge were significantly smaller [58.9% and 67.3% of preoperative (P < 0.001), respectively]. The number of patients with grade C (severe) lumbar stenosis also dropped significantly (preoperative, 17.6%; 2 years postoperative, 0%). There were no significant differences in JOABPEQ results at 6 months, 1 year, and 2 years postsurgery. CONCLUSION: Indirect decompression produces immediate positive results that continue to improve over time. The cross-sectional area of the thecal sac doubled by 2 years after surgery, and the ligamentum flavum cross-sectional area and disc bulging both shrank significantly. At the same time, however, postoperative radiographical improvements do not appear to correlate with clinical symptoms. LEVEL OF EVIDENCE: 3.

A prospective cohort study. The aim of this study was to investigate radiographical changes related to indirect decompression using lateral lumbar interbody fusion (LLIF) with posterior fixation. Indirect lumbar decompression via LLIF is used to treat degenerative lumbar diseases requiring neural decompression. Although evidence suggests that thecal sac enlargement follows shortly after surgery, few studies have described the postoperative changes on MRIs. This study involved 102 patients who underwent indirect decompression at 136 levels, with LLIF and posterior fixation. Magnetic resonance imaging (MRIs) were collected preoperatively and several times postoperatively (over a 2-year period starting immediately after surgery). We then quantified the cross-sectional areas of the thecal sac and ligamentum flavum, as well as the anteroposterior diameter of disc bulging, and qualitatively assessed lumbar spinal stenosis according to a modified version of Schizas' classification [Grades A (mild) to C (severe)]. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used for the assessment of the clinical symptoms. All changes were observable immediately after surgery, progressed over time, and were significantly different statistically at 2 years after surgery. The thecal sac was significantly larger (189% of preoperative; P < 0.0001), while the ligamentum flavum and disc bulge were significantly smaller [58.9% and 67.3% of preoperative (P < 0.001), respectively]. The number of patients with grade C (severe) lumbar stenosis also dropped significantly (preoperative, 17.6%; 2 years postoperative, 0%). There were no significant differences in JOABPEQ results at 6 months, 1 year, and 2 years postsurgery. Indirect decompression produces immediate positive results that continue to improve over time. The cross-sectional area of the thecal sac doubled by 2 years after surgery, and the ligamentum flavum cross-sectional area and disc bulging both shrank significantly. At the same time, however, postoperative radiographical improvements do not appear to correlate with clinical symptoms. Level of Evidence: 3.

What Are the Important Predictors of Postoperative Functional Recovery in Patients With Cervical OPLL? Results of a Multivariate Analysis.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The objective of this study was to identify important predictors of poor functional recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: This was a retrospective cohort study of 142 OPLL patients with laminoplasty; 135 had complete radiographical data and were followed up for ≥2 years. The following OPLL characteristics were compared between patients with "good" and "poor" outcomes (Japanese Orthopedic Association [JOA] recovery rate ≥50% and <50%, respectively): number of ossified levels, OPLL classification, ossification shape, K-line, canal-occupying ratio, and increased magnetic resonance imaging (MRI) signal intensity. Predictors of functional recovery were identified. RESULTS: Pre- and postoperative (2 years following surgery) JOA scores were 10.6 ± 2.9 and 14.1 ± 2.2, respectively, indicating significant improvement following laminoplasty (P < .001). The average JOA recovery rate was 53.4% ± 34.7%, with 81 (60.0%) and 54 (40.0%) patients in the better and poorer neurological outcome groups, respectively. The canal occupation ratio of OPLL ≤60%/>60% were 117 (86.7%) and 18 (13.3%) patients, respectively. In the stepwise logistic regression analysis, an occupation ratio greater than 60% was identified as a significant factor for poor postoperative neurological outcome (relative risk, 4.82; 95% confidential interval, 1.61-14.46, P = .005). CONCLUSIONS: This multivariate analysis demonstrated a large size OPLL (occupying ratio >60%) was associated with a risk of poor neurological recovery roughly 5 times greater, and therefore other types of surgery are recommended in cases with such a ratio.

Factors Affecting Postoperative Sagittal Alignment after Lateral Lumbar Interbody Fusion in Adult Spinal Deformity: Posterior Osteotomy, Anterior Longitudinal Ligament Rupture, and Endplate Injury.

Study Design: Prospective cohort study. Purpose: To identify factors that affect sagittal alignment correction in lateral lumbar interbody fusion (LIF) surgery for adult spinal deformity (ASD) and to investigate the degree of correction in each condition. Overview of Literature: LIF is a useful procedure for ASD, but the degree of correction can be affected by posterior osteotomy, intraoperative endplate injury, or anterior longitudinal ligament (ALL) rupture. Methods: Radiographical data for 30 patients who underwent LIF for ASD were examined prospectively. All underwent two-stage surgery (LIF followed by posterior fixation). Radiographical parameters were measured preoperatively, after LIF, and after posterior fixation; these included the segmental lordotic angle, lumbar lordosis (LL), and other sagittal alignment factors. Results: LL was corrected from 16.5°±16.7° preoperatively to 33.4°±13.8° after LIF (p <0.001) and then to 52.1°±7.9° following posterior fixation (p <0.001). At levels where Schwab grade 2 osteotomy was performed, the acquired segmental lordotic angles from the preoperative value to after posterior fixation and from after LIF to after posterior fixation were 19.5°±9.2° and 9.9°±3.9°, respectively. On average, 12.4° more was added than in cases without osteotomy. Endplate injury was identified at 21 levels (19.4%) after LIF, with a mean loss of 3.4° in the acquired segmental lordotic angle (5.3°±8.4° and 1.9°±5.9° without and with endplate injury, respectively). ALL rupture was identified at seven levels (6.5%), and on average 19.3° more was added in these cases between the preoperative and postoperative values than in cases without ALL rupture. Conclusions: LIF provides adequate sagittal alignment restoration for ASD, but the degree of correction is affected by grade 2 osteotomy, intraoperative endplate injury, and ALL rupture.