Glycan sulfation patterns define autophagy flux at axon tip via PTPRσ-cortactin axis.

Chondroitin sulfate (CS) and heparan sulfate (HS) are glycosaminoglycans that both bind the receptor-type protein tyrosine phosphatase PTPRσ, affecting axonal regeneration. CS inhibits axonal growth, while HS promotes it. Here, we have prepared a library of HS octasaccharides and, together with synthetic CS oligomers, we found that PTPRσ preferentially interacts with CS-E-a rare sulfation pattern in natural CS-and most HS oligomers bearing sulfate and sulfamate groups. Consequently, short and long stretches of natural CS and HS, respectively, bind to PTPRσ. CS activates PTPRσ, which dephosphorylates cortactin-herein identified as a new PTPRσ substrate-and disrupts autophagy flux at the autophagosome-lysosome fusion step. Such disruption is required and sufficient for dystrophic endball formation and inhibition of axonal regeneration. Therefore, sulfation patterns determine the length of the glycosaminoglycan segment that bind to PTPRσ and define the fate of axonal regeneration through a mechanism involving PTPRσ, cortactin and autophagy.

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.

Sarcopenia and physical function are associated with inflammation and arteriosclerosis in community-dwelling people: The Yakumo study.

OBJECTIVES: Sarcopenia reduces physical function, while chronic inflammation causes arteriosclerosis and decreases skeletal muscle. We conducted a cross-sectional study to elucidate the associations among sarcopenia, physical function, arteriosclerosis, and inflammation in community-dwelling people. METHODS: We recruited 335 participants in an annual health checkup. We diagnosed sarcopenia based on appendicular skeletal muscle mass index (aSMI) assessed by bioelectrical impedance analysis. We measured several physical function tests, blood pressure, and serum levels of high-sensitivity C-reactive protein (hs-CRP), total cholesterol, and low-density lipoprotein cholesterol. RESULTS: After controlling for age, sex, and BMI, participants in the sarcopenia group showed lower performance in all measured physical tests than the normal group. Arteriosclerosis risk factors, including blood pressure, cholesterol levels, and hs-CRP, were significantly higher in the sarcopenia group than in the normal group. hs-CRP and total cholesterol levels were significant risk factors of sarcopenia. The aSMI, grip strength, and maximum stride length were negatively related to hs-CRP level. CONCLUSIONS: Community-dwelling people with sarcopenia had higher levels of hs-CRP and a higher risk for arteriosclerosis. The serum level of hs-CRP was an independent risk factor for sarcopenia and was associated with physical function. These findings indicate that chronic inflammation may relate arteriosclerosis and sarcopenia simultaneously.

Analysis of cervical kyphosis and spinal balance in young idiopathic scoliosis patients classified by the apex of thoracic kyphosis.

PURPOSE: Sagittal balance has recently been the focus of studies aimed at understanding the correction force required for both coronal and sagittal malalignment. However, the correlation between cervical kyphosis and sagittal balance in AIS patients has yet to be thoroughly investigated. This study aimed to clarify the correlation between cervical alignment and spinal balance in patients with adolescent idiopathic scoliosis (AIS). Here, we hypothesized that cervical kyphosis patients can be classified into groups by the apex of thoracic kyphosis. METHODS: This study included 92 AIS patients (84 females, 8 males; mean age, 15.1 years). Patients were divided into the cervical lordosis (CL), cervical sigmoid (CS), or cervical kyphosis (CK) groups and further classified according to the apex of thoracic kyphosis into High (above T3), Middle (T4-T9), and Low (below T10) groups. RESULTS: There were 17 (18.5 %), 22 (23.9 %), and 53 (57.6 %) patients with CL, CS, and CK, respectively. In the CK group, 13 had CK-High, 35 had CK-Middle, and 5 had CK-Low. The C7 sagittal vertical axis (C7SVA) measurements were most backward in CK-High and most forward in CK-Low. The T5-12 kyphosis (TK) measurement was significantly lower in CK-High. CONCLUSIONS: Most AIS patients had kyphotic cervical alignment. Patients with CK can be classified as having CK-High, CK-Middle, or CK-Low according to the apex of thoracic kyphosis. CK-High is due to thoracic hypokyphosis with a backward balanced C7SVA. CK-Middle is well-balanced cervical kyphosis. CK-Low has forward-bent global kyphosis of the cervicothoracic spine that positioned the C7SVA forward.

Predictive factors for a distal adjacent disorder with L3 as the lowest instrumented vertebra in Lenke 5C patients.

OBJECTIVE: To investigate what type of Lenke 5C patient benefits most from a fusion to L3 as the LIV. METHODS: The subjects were 16 patients who underwent fusion surgery to L3 as the lowest instrumented vertebra (LIV), and who were then observed for a minimum of 2 years postoperatively. We considered an unsatisfactory radiologic outcome for the distal adjacent curve (DAD) to be an L3 or L4 tilt angle less than 10° or L3/4 disc wedging less than 10°. Patients were divided into 2 groups based on the radiologic outcome of the distal curve: the distal adjacent disorder+ (DAD+) and the distal adjacent disorder-(DAD-). We compared global balance, Cobb angles (thoracic and lumbar), L3 and L4 tilt angles and L3/4/5 disc angles between the 2 groups on preoperative, postoperative and final radiographs. RESULTS: Seven patients (43.8 %) met the criteria for the DAD+ group. On preoperative radiographs, there was a significant difference in the L3/4 disc angle: the DAD+ group opened to the preoperative convex side (-2.1° ± 3.0°) and the DAD- group opened to the preoperative concave side (4.7° ± 5.1°). The standing L3- and L4-CSVL and the L4-CSVL under traction were significantly different. CONCLUSIONS: In Lenke 5C patients who underwent fusion surgery to L3 as the LIV, preoperative LIV (L3), LIV + 1 (L4) translation and L3/4 disc angle on standing, plus LIV + 1 translation under traction were very important parameters correlating with postoperative global coronal balance.

Utility of a 3-dimensional full-scale NaCl model for rib strut grafting for anterior fusion for cervicothoracic kyphosis.

In severe spinal deformity, pain and neurological disorder may be caused by spinal cord compression. Surgery for spinal reconstruction is desirable, but may be difficult in a case with severe deformity. Here, we show the utility of a 3D NaCl (salt) model in preoperative planning of anterior reconstruction using a rib strut in a 49-year-old male patient with cervicothoracic degenerative spondylosis. We performed surgery in two stages: a posterior approach with decompression and posterior instrumentation with a pedicle screw; followed by a second operation using an anterior approach, for which we created a 3D NaCl model including the cervicothoracic lesion, spinal deformity, and ribs for anterior reconstruction. The 3D NaCl model was easily scraped compared with a conventional plaster model and was useful for planning of resection and identification of a suitable rib for grafting in a preoperative simulation. Surgery was performed successfully with reference to the 3D NaCl model. We conclude that preoperative simulation with a 3D NaCl model contributes to performance of anterior reconstruction using a rib strut in a case of cervicothoracic deformity.

Tuberculous meningitis with dementia as the presenting symptom after intramedullary spinal cord tumor resection.

Early-stage TB meningitis has no specific symptoms in patients, potentially leading to delayed diagnosis and consequently worsening prognosis. The authors present the fatal case with a delayed diagnosis of tuberculous (TB) meningitis with dementia as the presenting symptom after intramedullary spinal cord tumor resection. The medical records, operative reports, and radiographical imaging studies of a single patient were retrospectively reviewed. A 77-year-old man who underwent thoracic intramedullary hemangioblastoma resection for 2 times. The postoperative course was uneventful, but 1.5 months after surgery, the patient suffered from dementia with memory loss and diminished motivation and speech in the absence of a fever. No abnormalities were detected on blood test, brain computed tomography and cerebrospinal fluid (CSF) analysis. A sputum sample was negative for Mycobacterium tuberculosis in the QuantiFERON®-TB Gold (QFT-G) In-Tube Test and the tuberculin skin test was also negative. The patient was diagnosed with senile dementia by a psychiatrist. However, the patient's symptoms progressively worsened. Despite the absence of TB meningitis findings, we suspected TB meningitis from the patient's history, and administered a four-drug regimen. However the patient died 29 days after admission, subsequently M. tuberculosis was detected in the CSF sample. This case is a rare case of TB meningitis initially mistaken for dementia after intramedullary spinal cord tumor resection. Symptoms of dementia after intramedullary spinal cord tumor resection should first be suspected as one of TB meningitis, even if the tests for meningitis are negative. We propose that anti-tuberculosis therapy should be immediately initiated in cases of suspected TB meningitis prior to positive identification on culture.

Hyperamylasemia and pancreatitis following posterior spinal surgery.

BACKGROUND: Postoperative pancreatitis has primarily been reported as a complication of abdominal surgery, but there are some case reports of postoperative pancreatitis after spinal surgery. The objective of this study was to investigate a case series of hyperamylasemia and pancreatitis following posterior spinal surgery. METHODS: The serum amylase level was measured following posterior spinal surgery in the prone position. Patients were divided into groups with a normal serum amylase level (0-125 IU/L) and with hyperamylasemia (>125 IU/L), based on the upper limit of normal of 125 IU/L in our institution. Relationships among preoperative factors, perioperative factors, and the serum amylase level were investigated. RESULTS: Hyperamylasemia (serum amylase >125 IU/L) following posterior spinal surgery was found in 92 cases (35 %). Among perioperative factors, intraoperative estimated blood loss (EBL) and operating time were significantly higher in patients with high serum amylase than in patients with normal serum amylase (P < 0.01). In a multivariate regression model, intraoperative EBL (OR 1.001, 95 % CI 1.000-1.002; P = 0.001) and operation time (OR 1.006, 95 % CI 1.003-1.009; P = 0.006) were significantly associated with postoperative pancreatitis. Serum amylase levels of ≥ 5 times the upper limit of normal were found in six cases. Five of these cases were asymptomatic and one was caused by severe pancreatitis. CONCLUSIONS: In our case series, intraoperative blood loss caused a rise in the serum amylase level following posterior spinal surgery. Thus, this level should be carefully monitored after spinal surgery with significant blood loss. Clinical symptoms of pancreatitis, such as abdominal pain and vomiting, should also be monitored following spinal surgery.

Volumetric change in interbody bone graft after posterior lumbar interbody fusion (PLIF): a prospective study.

PURPOSE: The purpose of this study is to quantify the change in the volume of the interbody bone graft after the PLIF and monitor the change over time for subsequent analysis. METHODS: The 114 cases were selected as the subjects of this study. The observation period was for 5 years following the surgery. The volume of the bone graft in the interbody space was calculated by summing up the cross-sectional area of the bone graft on each axial image multiplied by the height (2 mm) (the volume of the two cages was excluded). The volume ratio (%) = (bone graft volume)/(total volume of the interbody space - cage volume) was used for the purpose of evaluation. RESULTS: The volumetric change of the bone graft was 51 % (3 months), 53 % (6 months), 54 % (1 year), 55 % (2 years), 59 % (3 years), 62 % (4 years), and 72 % (5 years), indicating a continued increase up to the 5-year mark. In particular, a significant increase was observed from the second year as compared with the previous years' result. Additionally, the volumetric increase from the second year to the fifth year was significantly higher than that before the second year. CONCLUSIONS: The post-PLIF volumes of interbody bone grafts exhibited increases particularly from the second to fifth years after the procedure. Even the elderly and those with poor bone qualities can expect to have volumetric increases over time. Sufficient interbody space should be secured for accommodating bone grafts by intraoperative reduction, wherever possible.

Predisposing factors for surgical site infection of spinal instrumentation surgery for diabetes patients.

PURPOSE: Diabetes mellitus (DM) is known as an important risk factor for surgical site infection (SSI) in spine surgery. It is still unclear however which DM-related parameters have stronger influence on SSI. The purpose of this study is to determine predisposing factors for SSI following spinal instrumentation surgery for patients with DM. METHODS: 110 DM patients (66 males and 44 females) who underwent spinal instrumentation surgery in one institute were enrolled in this study. For each patient, various preoperative or intraoperative parameters were reviewed from medical records. Patients were divided into two groups (SSI or non-SSI) based on the postoperative course. Each parameter between these two groups was compared. Univariate and multivariate analyses were performed to determine predisposing factor for SSI. RESULTS: The SSI group consisted of 11 patients (10%), and the non-SSI group of 99 patients (90%). Univariate analysis revealed that preoperative proteinuria (p = 0.01), operation time (p = 0.04) and estimated blood loss (p = 0.02) were significantly higher in the SSI group compared to the non-SSI group. Multivariate logistic regression identified preoperative proteinuria as a statistically significant predictor of SSI (OR 6.28, 95% CI 1.58-25.0, p = 0.009). CONCLUSIONS: Proteinuria is a significant predisposing factor for SSI in spinal instrumentation surgery for DM patients. DM patients with proteinuria who are likely to suffer latent nephropathy have a potential risk for SSI. For them less invasive surgery is recommended for spinal instrumentation. In this retrospective study, there was no significant difference of preoperative condition in glycemic control between the two groups.

The effects of surgery on locomotion in elderly patients with cervical spondylotic myelopathy.

PURPOSE: This study aimed to evaluate the effects of surgery on locomotor ability in patients with cervical spondylotic myelopathy (CSM) and compare the results between elderly and younger patients. METHODS: A total of 369 consecutive patients who underwent expansive laminoplasty for CSM were prospectively analysed. Patients were divided into two age groups of ≥ 75 years (elderly group, 76 patients) and <75 years (younger group, 293 patients). Locomotor ability was estimated using part of the functional independence measure (FIM). The sum of gait and stairs items [functional independence measure (locomotion), FIM-L; possible scores, 2-14] and neurological status were estimated using the Japanese Orthopaedic Association (JOA) score (possible score, 0-17). Pre-operative neurological anamnesis was reviewed, and the surgical results of elderly patients with or without co-existing neurological history were evaluated to determine the origin of locomotor disability. RESULTS: Peri-operative FIM-L and JOA scores were significantly lower in the elderly group than in the younger group, and the opposite was true for improved FIM score. Cerebral infarction and previous lumbar surgery were identified as neurological co-morbidities in the elderly group. However, there was no significant difference in surgical results between elderly patients with and without co-existing neurological disorders. CONCLUSIONS: Decompression surgery can improve locomotor ability and decrease nursing care requirements among elderly patients with CSM. However, other neurological diseases can co-exist in elderly patients, making it difficult to diagnose the origin of locomotor disability. Therefore, detailed peri-operative work-up and timely decompression should be given priority to avoid progression towards fixed locomotor disability.

Cardiopulmonary function in elderly patients with cervical spondylotic myelopathy.

BACKGROUND: Most elderly patients have cardiopulmonary diseases anamnesis and a perceived risk of perioperative complications. The responsible lesion may be located more cranially in elderly patients with cervical spondylotic myelopathy (CSM) compared with that in younger patients. The study aimed at evaluating cardiopulmonary dysfunction of CSM and effects of surgery on cardiopulmonary function and perioperative complications. METHODS: Thirty-one consecutive patients (>75 years of age) who underwent expansive laminoplasty for CSM were compared with 30 age-matched controls who underwent lumbar decompression. The ejection fraction (EF), percent vital capacity (%VC), and forced expiratory volume percent in 1 s (FEV(1)%) before and 6 months after surgery were analyzed by cardiac ultrasonography and spirometry. Furthermore, neurological status, lesion level, and perioperative complications were evaluated. RESULTS: The mean %VC significantly decreased in the study group compared with that in the control group before surgery (89.4 ± 12.4 vs. 96.5 ± 12.7, P = 0.032). EF, %VC, and FEV(1)% showed no significant differences after surgery. The mean %VC was significantly lower in the cranial group with lesions above C4 compared with that in the caudal group before (81.8 ± 10.0 vs. 95.0 ± 11.2, P = 0.0021) and after (83.8 ± 9.7 vs. 92.1 ± 11.8, P = 0.047) surgery. The Japanese Orthopaedic Association score significantly improved after surgery (P < 0.001), and the mean recovery rate was 48.3%. The occurrence of perioperative complications was significantly higher in the study group compared with that in the control group (P = 0.018). CONCLUSIONS: Elderly CSM patients with cranial lesions have a decreased %VC and high risk of perioperative cardiopulmonary complications. Therefore, detailed perioperative workup and timely decompression should be performed to avoid progression toward fixed neurological deficits and cardiopulmonary dysfunction whether or not they result from myelopathy itself.

An intraoperative 3D image-based navigation error during cervical pedicle screw insertion.

A 67-year-old man underwent posterior cervical decompression surgery for ossification of the posterior longitudinal ligament (OPLL) with fixation using cervical pedicle screws (CPSs) guided by intraoperative 3D image-based navigation. Intraoperatively, while creating the screw hole using the navigation probe, the virtual trajectory on the intraoperative navigation screen showed a 10-degree angle discrepancy in the axial plane depending on whether a probing force was or was not applied for making the hole. This was potentially caused by vertebra rotation and a bent probe. Consequently, the CPSs were placed more laterally than the ideal trajectory, which resulted in <2 mm lateral perforation to the foramen transversarium. There were no screw insertion-related perioperative complications. Based on this case, we conclude that navigation error during CPS insertion can occur even with intraoperative 3D image-based navigation. The risk of a bowed navigation probe caused by posterior cervical muscle and vertebra rotation should be considered, even with use of a navigation reference frame.

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.

Postoperative iatrogenic spinal cord herniation: three case reports with a literature review.

Although a majority of spinal cord herniation reportedly occurs idiopathically, postoperative iatrogenic spinal cord herniation is rare. Therefore, the incidence rate, pathogenic mechanism, and clinical outcomes are not clear. We present three cases of postoperative iatrogenic spinal cord herniation and present a literature review. Our data base included 32253 patients who underwent spinal surgery, and among these patients, 3 showed postoperative spinal cord herniation. Postoperative spinal cord herniation was observed in a 55-year-old man and a 60-year-old man. Both these patients underwent cervical laminoplasty for degenerative cervical myelopathy; however, intraoperative dural tear was reported. They presented with severe quadriplegia and sensory disorders at 8 years and 2 months after initial surgery. The third case of postoperative spinal cord herniation was of a 47-year-old woman who underwent Th11/12 schwannoma resection. Her neurological symptoms did not improve after tumor resection, and MRI at 2 months after surgery revealed spinal cord herniation. All the 3 patients underwent spinal cord reduction surgery; one patient showed sufficient neurological improvement while 2 patients with cervical spinal cord herniation showed limited neurological improvement due to preoperative severe quadriplegia. Although postoperative iatrogenic spinal cord herniation is a relatively rare pathology, careful observation with postoperative MRI is required in cases of patients with new neurological symptoms after dural injury and durotomy.

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.

Unplanned Second-Stage Decompression for Neurological Deterioration Caused by Central Canal Stenosis after Indirect Lumbar Decompression Surgery.

Study Design: Prospective cohort study. Purpose: This study aimed to identify risk factors for unplanned second-stage decompression for postoperative neurological deficit after indirect decompression using lateral lumbar interbody fusion (LLIF) with posterior fixation. Overview of Literature: Indirect lumbar decompression with LLIF has been used as a minimally invasive alternative to direct decompression to treat degenerative lumbar diseases requiring neural decompression. However, evidence on the prevalence of neurological deficits caused by spinal canal stenosis after indirect decompression is limited. Methods: This study included 158 patients (mean age, 71.13±7.98 years; male/female ratio, 67/91) who underwent indirect decompression with LLIF and posterior fixation. Indirect decompression was performed at 271 levels (mean level, 1.71±0.97). Logistic regression analysis was used to identify the risk factors for postoperative neurological deficits. The variables included were age, sex, body mass index, presence of primary diseases, diabetes mellitus, preoperative motor deficit, levels operated on, preoperative severity of lumbar stenosis, and preoperative Japanese Orthopedic Association (JOA) score. Results: Postoperative neurological deficit due to spinal canal stenosis occurred in three patients (1.9%). Spinal stenosis due to hemodialysis (p<0.001), ligament ossification (p<0.001), presence of preoperative motor paralysis (p<0.001), low JOA score (p=0.004), and severe canal stenosis (p=0.02) were significantly more frequent in the paralysis group. Conclusions: Severe preoperative canal stenosis and neurological deficit were identified as risk factors for postoperative neurological deterioration caused by spinal canal stenosis. Additionally, uncommon diseases, such as spinal stenosis due to hemodialysis and ligament ossification, increased the risk of postoperative neurological deficit; therefore, in such cases, indirect decompression is contraindicated.