The Influence of Titanium-coated Poryetheretherketone Cages in Fusion Status after Posterior Lumbar Interbody Fusion with Cortical Bone Trajectory Screw Fixation.

OBJECTIVE: Posterior lumbar interbody fusion (PLIF) with cortical bone trajectory (CBT) screw fixation (CBT-PLIF) shows potential for reducing adjacent segmental disease. Previously, our investigations revealed a relatively lower fusion rate with the use of carbon fiber-reinforced polyetheretherketone (CP) cages in CBT-PLIF compared with traditional pedicle screw fixation (PS-PLIF) using CP cages. This study aims to evaluate whether the implementation of titanium-coated polyetheretherketone (TP) cages can enhance fusion outcomes in CBT-PLIF. METHODS: A retrospective analysis was conducted on 68 consecutive patients who underwent CBT-PLIF with TP cages (TP group) and 89 patients who underwent CBT-PLIF with CP cages (CP group). Fusion status was assessed using computed tomography at 1 year postoperatively and dynamic plain radiographs at 2 years postoperatively. RESULTS: No statistically significant differences in fusion rates were observed at 1 and 2 years postoperatively between the TP group (86.8% and 89.7%, respectively) and the CP group (77.5% and 88.8%, respectively). Notably, the CP group exhibited a significant improvement in fusion rate from 1 to 2 years postoperatively (P = 0.002), while no significant improvement was observed in the TP group. CONCLUSIONS: Examination of temporal changes in fusion rates reveals that only the TP group achieved a peak fusion rate 1 year postoperatively. This implies that TP cages may enhance the fusion process even after CBT-PLIF. Nevertheless, the definitive efficacy of TP cages for CBT-PLIF remains uncertain in the context of overall fusion rates.

Freehand screw insertion technique without image guidance for the cortical bone trajectory screw in posterior lumbar interbody fusion: what affects screw misplacement?

OBJECTIVE: Cortical bone trajectory (CBT) screw insertion using a freehand technique is considered less feasible than guided techniques, due to the lack of readily identifiable visual landmarks. However, in posterior lumbar interbody fusion (PLIF), after resection of the posterior anatomy, the pedicles themselves, into which implantation is performed, are palpable from the spinal canal and neural foramen. With the help of pedicle wall probing, the authors have placed CBT screws using a freehand technique without image guidance in PLIF. This technique has advantages of no radiation exposure and no requirement for expensive devices, but the disadvantage of reduced accuracy in screw placement. To address the problem of symptomatic breaches with this freehand technique, variables related to unacceptable screw positioning and need for revisions were investigated. METHODS: From 2014 to 2020, 182 of 426 patients with single-level PLIF were enrolled according to the combined criteria of L4-5 level, excluding cases of revision and isthmic spondylolisthesis; using screws 5.5 mm in diameter; and operated by right-handed surgeons. We studied the number of misplaced screws found and replaced during initial surgeries. Using multiplanar reconstruction CT postoperatively, 692 screw positions on images were classified using previously reported grading criteria. Details of pedicle breaches requiring revisions were studied. We conducted a statistical analysis of the relationship between unacceptable (perforations > 2 mm) misplacements and four variables: level, laterality, spinal deformity, and experiences of surgeons. RESULTS: Three screws in L4 and another in L5 were revised during initial surgeries. The total rate of unacceptable screws on CT examinations was 3.3%. Three screws in L4 and another in L5 breached inferomedial pedicle walls in grade 3 and required revisions. The revision rate was 2.2%. The percentage of unacceptable screws was 5.2% in L4 and 1.7% in L5 (p < 0.05), whereas other variables showed no significant differences. CONCLUSIONS: A freehand technique can be feasible for CBT screw insertion in PLIF, balancing the risks of 3.3% unacceptable misplacements and 2.2% revisions with the benefits of no radiation exposure and no need for expensive devices. Pedicle palpation in L4 is the key to safety, even though it requires deeper and more difficult probing. In the initial surgeries and revisions, 75% of revised screws were observed in L4, and unacceptable screw positions were more likely to be found in L4 than in L5.

Impacts of postoperative changes of segmental mobility on neurological improvement after laminoplasty for cervical ossification of the posterior longitudinal ligament.

ABSTRACT: Several studies have demonstrated that the dynamic factor at the mobile segment affects the severity of myelopathy in patients with cervical ossification of the posterior longitudinal ligament (C-OPLL), and posterior decompression supplemented with posterior instrumented fusion at the mobile segment provides good neurological improvement. However, there have been few reports of changes in range of motion at the mobile segment (segmental ROM) after laminoplasty (LP). The aim of this study was thus to retrospectively investigate changes in segmental ROM after LP and the impacts of these changes on neurological improvement in patients with C-OPLL.A total of 51 consecutive patients who underwent LP for C-OPLL since May 2010 and were followed for at least 2 years after surgery were included in this study. Neurological status was assessed using the Japanese Orthopaedic Association (JOA) score before surgery and at 2-year follow-up. Segmental ROM at the responsible level for myelopathy was measured preoperatively and at 2-year follow-up using lateral flexion-extension radiographs of the cervical spine.The mean JOA score improved significantly from 10.7 points preoperatively to 13.5 points at 2 years after surgery (mean recovery rate, 45.0%). The mean segmental ROM decreased significantly from 6.5 degrees before surgery to 3.2 degrees at 2 years after surgery. In the good clinical outcome group (recovery rate of the JOA score ≥50%; n = 22), the mean segmental ROM decreased significantly from 5.8 degrees preoperatively to 3.0 degrees postoperatively. It also decreased significantly from 7.1 degrees to 3.4 degrees in the poor clinical outcome group (recovery rate of the JOA score <50%; n = 29).This study showed that segmental ROM was stabilized after LP in most patients with C-OPLL. Neither preoperative nor postoperative segmental ROM showed significant differences between the good and poor clinical outcome groups and neither a postoperative increase nor decrease of segmental ROM significantly affected the recovery rate of the JOA score.

Postoperative Loss of Lumbar Lordosis Affects Clinical Outcomes in Patients with Pseudoarthrosis after Posterior Lumbar Interbody Fusion Using Cortical Bone Trajectory Screw Fixation.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to investigate relationships between clinical outcomes and radiographic parameters in patients with pseudoarthrosis after posterior lumbar interbody fusion (PLIF). OVERVIEW OF LITERATURE: In some patients with pseudoarthrosis after PLIF, clinical symptoms improve following surgery, although pseudoarthrosis can often be one of the complications. However, there are no previous reports describing differences between patients with pseudoarthrosis after PLIF who have obtained better clinical outcomes and those who have not. METHODS: Twenty-seven patients who were diagnosed with pseudoarthrosis after single-level PLIF with cortical bone trajectory screw fixation (CBT-PLIF) were enrolled in this study. They were divided into two groups based on mean improvement of 22 points on the Oswestry Disability Index (ODI) at the 2-year follow-up. Group G consisted of 15 patients who showed improvement on the ODI of ≥22 points, and group P consisted of the residual 12 patients. Radiographic parameters, percentage of slip, lumbar lordosis (LL), segmental lordosis, segmental range of motion, screw loosening, and subsidence were compared between the two groups. RESULTS: There were no significant differences between the two groups on radiographic parameters except for postoperative changes in LL. Although surgery-induced changes in LL showed no significant difference between the two groups, changes in LL from before surgery to 2-year follow-up and during postoperative 2-year follow-up were significantly better in group G (mean change of LL: +3.5° and +5.1°, respectively) compared to group P (mean change of LL: -4.6° and -0.5°, respectively) (p<0.01 and 0.05, respectively). CONCLUSIONS: Patients with greater improvement in ODI gained LL over the 2-year follow-up, whereas patients with less improvement in ODI lost LL during the 2-year follow-up. These results indicate that there is a significant correlation between clinical outcomes and LL even in patients with pseudoarthrosis after single-level CBT-PLIF.

Differences in Postoperative Changes of Cervical Sagittal Alignment and Balance After Laminoplasty Between Cervical Spondylotic Myelopathy and Cervical Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To compare postoperative changes of cervical sagittal alignment (CSA) and cervical sagittal balance (CSB) after laminoplasty between cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) and to examine impacts of these radiologic changes on neurologic outcomes. METHODS: A total of 168 consecutive patients with CSM (CSM group) and 51 consecutive patients with OPLL (OPLL group) were included. As indicators of CSA and CSB, the C2-7 angle and C1-C7 sagittal vertical axis (SVA) were, respectively, measured before surgery and at 2-year follow-up. Neurologic status was assessed using the Japanese Orthopaedic Association score before surgery and at 2-year follow-up. RESULTS: Whereas both postoperative loss of C2-7 angle and increase of C1-C7 SVA were significantly greater in the elderly subgroup of the CSM group, patient age did not significantly affect these changes in the OPLL group. Preservation of C7 maintained C1-C7 SVA at postoperative 2 years only in the CSM group. Postoperative cervical kyphosis and sagittal imbalance significantly decreased neurologic improvement in the CSM group but not in the OPLL group. CONCLUSIONS: Elderly patients with CSM have significantly greater postoperative loss of lordosis and increase in C1-C7 SVA than nonelderly patients, and both postoperative kyphotic deformity and sagittal imbalance significantly deteriorate neurologic recovery. On the other hand, although patients with OPLL, irrespective of patient age and preservation of C7, have significantly more loss of lordosis and increase in C1-C7 SVA than CSM patients, neither postoperative kyphotic deformity nor sagittal imbalance significantly deteriorates neurologic recovery in OPLL patients.

Early Fusion Status after Posterior Lumbar Interbody Fusion with Cortical Bone Trajectory Screw Fixation: A Comparison of Titanium-Coated Polyetheretherketone Cages and Carbon Polyetheretherketone Cages.

STUDY DESIGN: Retrospective cohort study. PURPOSE: We recently reported that when compared to posterior lumbar interbody fusion (PLIF) using traditional pedicle screw fixation, PLIF with cortical bone trajectory screw fixation (CBT-PLIF) provided favorable clinical outcomes and reduced the incidence of symptomatic adjacent segment pathology, but resulted in relatively lower fusion rates. Since titanium-coated polyetheretherketone (PEEK) cages (TP) could improve and accelerate fusion status after CBT-PLIF, early fusion status was compared between CBT-PLIF using TP and carbon PEEK cages (CP). OVERVIEW OF LITERATURE: A systematic review demonstrated that clinical studies at this early stage show similar fusion rates for TP compared to PEEK cages. METHODS: We studied 36 consecutive patients undergoing CBT-PLIF with TP (TP group) and 92 undergoing CBT-PLIF with CP (CP group). On multiplanar reconstruction computed tomography (MPR-CT) at 6 months postoperatively, vertebral endplate cysts (cyst signs) were evaluated and classified as diffuse or local cysts. Early fusion status was assessed by dynamic plain radiographs and MPR-CT at 1 year postoperatively. RESULTS: The incidences of cyst signs, diffuse cysts, and early fusion rate in the TP and CP groups were 38.9% and 66.3% (p<0.01), 16.7% and 32.6% (p=0.07), and 83.3% and 79.3% (p>0.05), respectively. Combining the two groups, 22 of 36 patients with diffuse cysts had nonunion at 1-year follow-up, compared to only three of 92 patients with local cysts or without cyst signs (p<0.01). CONCLUSIONS: Despite having fewer patients with endplate cysts at 6 months (a known risk factor for nonunion), the TP group had the same fusion rate as the CP group at 1-year follow-up. Thus, TP did not accelerate the fusion process after CBT-PLIF.

Cortical bone trajectory screw fixation versus traditional pedicle screw fixation for 2-level posterior lumbar interbody fusion: comparison of surgical outcomes for 2-level degenerative lumbar spondylolisthesis.

OBJECTIVE The cortical bone trajectory (CBT) screw technique is a new nontraditional pedicle screw (PS) insertion method. However, the biomechanical behavior of multilevel CBT screw/rod fixation remains unclear, and surgical outcomes in patients after 2-level posterior lumbar interbody fusion (PLIF) using CBT screw fixation have not been reported. Thus, the purposes of this study were to examine the clinical and radiological outcomes after 2-level PLIF using CBT screw fixation for 2-level degenerative lumbar spondylolisthesis (DS) and to compare these outcomes with those after 2-level PLIF using traditional PS fixation. METHODS The study included 22 consecutively treated patients who underwent 2-level PLIF with CBT screw fixation for 2-level DS (CBT group, mean follow-up 39 months) and a historical control group of 20 consecutively treated patients who underwent 2-level PLIF using traditional PS fixation for 2-level DS (PS group, mean follow-up 35 months). Clinical symptoms were evaluated using the Japanese Orthopaedic Association (JOA) scoring system. Bony union was assessed by dynamic plain radiographs and CT images. Surgery-related complications, including symptomatic adjacent-segment disease (ASD), were examined. RESULTS The mean operative duration and intraoperative blood loss were 192 minutes and 495 ml in the CBT group and 218 minutes and 612 ml in the PS group, respectively (p < 0.05 and p > 0.05, respectively). The mean JOA score improved significantly from 12.3 points before surgery to 21.1 points (mean recovery rate 54.4%) at the latest follow-up in the CBT group and from 12.8 points before surgery to 20.4 points (mean recovery rate 51.8%) at the latest follow-up in the PS group (p > 0.05). Solid bony union was achieved at 90.9% of segments in the CBT group and 95.0% of segments in the PS group (p > 0.05). Symptomatic ASD developed in 2 patients in the CBT group (9.1%) and 4 patients in the PS group (20.0%, p > 0.05). CONCLUSIONS Two-level PLIF with CBT screw fixation for 2-level DS could be less invasive and result in improvement of clinical symptoms equal to those of 2-level PLIF using traditional PS fixation. The incidence of symptomatic ASD and the rate of bony union were lower in the CBT group than in the PS group, although these differences were not significant.

Fixation Strength of Caudal Pedicle Screws after Posterior Lumbar Interbody Fusion with the Modified Cortical Bone Trajectory Screw Method.

STUDY DESIGN: Clinical case series. PURPOSE: In the posterior lumbar interbody fusion (PLIF) procedure in our institute, the cephalad screw trajectory follows a mediolateral and caudocephalad directed path according to the original cortical bone trajectory (CBT) method. However, the starting point of the caudal screw is at the medial border of the pedicle on an articular surface of the superior articular process, and the trajectory takes a mediolateral path parallel to the cephalad endplate. The incidence of caudal screw loosening after PLIF with this modified CBT screw method was investigated, and significant risk factors for caudal screw loosening were evaluated. OVERVIEW OF LITERATURE: A biomechanical study of this modified caudal screw trajectory using the finite element method reported about a 20% increase in uniaxial yield pullout load compared with the traditional trajectory. However, there has been no clinical study concerning the fixation strength of this modified caudal screw trajectory. METHODS: The subjects were 193 consecutive patients who underwent single-level PLIF with modified CBT screw fixation. Caudal screw loosening was checked in computed tomography at 6 months after surgery, and screw loosening was defined as a radiolucency of 1 mm or more at the bone-screw interface. RESULTS: The incidence of caudal screw loosening after lumbosacral PLIF (46.2%) was significantly higher than that after floating PLIF (6.0%). No significant differences in sex, brand of the instruments, and diameter and length of the caudal screw were evident between patients with and without caudal screw loosening. Patients with caudal screw loosening were significantly older at the time of surgery than patients without caudal screw loosening. CONCLUSIONS: Fixation strength of the caudal screw after floating PLIF with this modified CBT screw technique was sufficiently acceptable. Fixation strength after the lumbosacral procedure was not.

Surgical outcomes after laminoplasty for cervical spondylotic myelopathy in patients with renal dysfunction and/or aortic arch calcification.

OBJECTIVE The authors recently reported that the presence of chronic kidney disease (CKD) and/or extended abdominal aortic calcification was associated with significantly worse clinical outcomes after posterior lumbar interbody fusion. CKD is one of the highest risk factors for systemic atherosclerosis. Therefore, impaired blood flow due to atherosclerosis could exacerbate degeneration of the cervical spine and neural tissue. However, there has been no report of a study evaluating the deleterious effects of CKD and atherosclerosis on the outcomes after decompression surgery for cervical compression myelopathy. The purpose of this study was thus to examine whether CKD and systemic atherosclerosis affect surgical outcomes after laminoplasty for cervical spondylotic myelopathy (CSM). METHODS The authors analyzed data from 127 consecutive cases involving patients who underwent laminoplasty for CSM and met their inclusion criteria. Stage 3-4 CKD was present as a preoperative comorbidity in 44 cases. Clinical status was assessed using the Japanese Orthopaedic Association (JOA) cervical myelopathy evaluation questionnaire before surgery and 2 years postoperatively. As a marker of systemic atherosclerosis, the presence of aortic arch calcification (AoAC) was assessed on preoperative chest radiographs. RESULTS AoAC was found on preoperative chest radiographs in 40 of 127 patients. Neither CKD nor AoAC had a statistically significant deleterious effect on preoperative JOA score. However, CKD and AoAC were significantly associated with reductions in both the JOA score recovery rate (mean 36.1% in patients with CKD vs 44.7% in those without CKD; 26.0% in patients with AoAC vs 48.9% in those without AoAC) and the change in JOA score at 2 years after surgery (mean 2.3 points in patients with CKD vs 3.1 points in those without CKD; 2.1 points for patients with AoAC vs 3.2 points for those without AoAC). A multivariate regression analysis showed that AoAC was a significant independent predictor of poor outcome with respect to both for the difference between follow-up and preoperative JOA scores and the JOA score recovery rate. CONCLUSIONS CKD and AoAC were associated with increased rates of poor neurological outcomes after laminoplasty for CSM, and AoAC was a significant independent predictive factor for poor outcome.

Posterior lumbar interbody fusion with cortical bone trajectory screw fixation versus posterior lumbar interbody fusion using traditional pedicle screw fixation for degenerative lumbar spondylolisthesis: a comparative study.

OBJECTIVE Several biomechanical studies have demonstrated the favorable mechanical properties of the cortical bone trajectory (CBT) screw. However, no reports have examined surgical outcomes of posterior lumbar interbody fusion (PLIF) with CBT screw fixation for degenerative spondylolisthesis (DS) compared with those after PLIF using traditional pedicle screw (PS) fixation. The purposes of this study were thus to elucidate surgical outcomes after PLIF with CBT screw fixation for DS and to compare these results with those after PLIF using traditional PS fixation. METHODS Ninety-five consecutive patients underwent PLIF with CBT screw fixation for DS (CBT group; mean followup 35 months). A historical control group consisted of 82 consecutive patients who underwent PLIF with traditional PS fixation (PS group; mean follow-up 40 months). Clinical status was assessed using the Japanese Orthopaedic Association (JOA) scale score. Fusion status was assessed by dynamic plain radiographs and CT. The need for additional surgery and surgery-related complications was also evaluated. RESULTS The mean JOA score improved significantly from 13.7 points before surgery to 23.3 points at the latest follow-up in the CBT group (mean recovery rate 64.4%), compared with 14.4 points preoperatively to 22.7 points at final follow-up in the PS group (mean recovery rate 55.8%; p < 0.05). Solid spinal fusion was achieved in 84 patients from the CBT group (88.4%) and in 79 patients from the PS group (96.3%, p > 0.05). Symptomatic adjacent-segment disease developed in 3 patients from the CBT group (3.2%) compared with 9 patients from the PS group (11.0%, p < 0.05). CONCLUSIONS PLIF with CBT screw fixation for DS provided comparable improvement of clinical symptoms with PLIF using traditional PS fixation. However, the successful fusion rate tended to be lower in the CBT group than in the PS group, although the difference was not statistically significant between the 2 groups.

Lifestyle-Related Diseases Affect Surgical Outcomes after Posterior Lumbar Interbody Fusion.

Study Design Retrospective study. Objective Hyperlipidemia (HL) and hypertension (HT) lead to systemic atherosclerosis. Not only atherosclerosis but also bone fragility and/or low bone mineral density result from diabetes mellitus (DM) and chronic kidney disease (CKD). The purpose of this study was to examine whether these lifestyle-related diseases affected surgical outcomes after posterior lumbar interbody fusion (PLIF). Methods The subjects comprised 122 consecutive patients who underwent single-level PLIF for degenerative lumbar spinal disorders. The clinical results were assessed using the Japanese Orthopaedic Association (JOA) score before surgery and at 2 years postoperatively. The fusion status was graded as union in situ, collapsed union, or nonunion at 2 years after surgery. The abdominal aorta calcification (AAC) score was assessed using preoperative lateral radiographs of the lumbar spine. Results HL did not significantly affect the JOA score recovery rate. On the other hand, HT and CKD (stage 3 to 4) had a significant adverse effect on the recovery rate. The recovery rate was also lower in the DM group than in the non-DM group, but the difference was not significant. The AAC score was negatively correlated with the JOA score recovery rate. The fusion status was not significantly affected by HL, HT, DM, or CKD; however, the AAC score was significantly higher in the collapsed union and nonunion group than in the union in situ group. Conclusions At 2 years after PLIF, the presence of HT, CKD, and AAC was associated with significantly worse clinical outcomes, and advanced AAC significantly affected fusion status.

Incidence and Risk Factors for Late Neurologic Deterioration after C3-C6 Laminoplasty for Cervical Spondylotic Myelopathy.

Study Design Retrospective study. Objective We previously reported that the long-term neurologic outcomes of C3-C6 laminoplasty for cervical spondylotic myelopathy (CSM) are satisfactory, with reduced frequencies of postoperative axial neck pain and kyphotic deformity. However, only 20 patients were included, which is a limitation in that study. The present study investigated the incidence of late neurologic deterioration (LND) of myelopathic symptoms after C3-C6 laminoplasty for CSM and attempted to identify significant risk factors for LND in a larger patient population. Methods Subjects comprised 137 consecutive patients with CSM who underwent C3-C6 laminoplasty (bilateral open-door laminoplasty, n = 85; unilateral open-door laminoplasty, n = 52) and were followed for >24 months (mean follow-up, 70 months; range, 25 to 124 months). The patients' medical records were examined for evidence of LND due to cervical myelopathy. The age at time of surgery, sex, surgical procedures, anteroposterior spinal canal diameter at the C7 level, type of C6 spinous process, pre- and postoperative C2-C7 angle, C3-C6 range of motion (ROM), and disk height at the C6-C7 level were analyzed to identify risk factors for LND. Results Three patients (2.2%) developed LND of myelopathic symptoms due to caudal segment pathology adjacent to the C3-C6 laminoplasty (LND group). In these three patients, mean Japanese Orthopaedic Association (JOA) score improved from 10.2 before surgery to 12.2 at the time of maximum recovery, and declined to 9.7 just before additional surgery. On the other hand, in 134 patients without LND (non-LND group), the mean JOA score significantly improved from 10.2 before surgery to 13.4 at the time of maximum recovery and was maintained by the final follow-up (13.2). Compared with the non-LND group, the LND group showed significantly smaller anteroposterior spinal canal diameter at C7, more restricted postoperative C3-C6 ROM, and greater postoperative decrease in disk height at C6-C7, although a logistic regression analysis showed no significant differences. Conclusions In patients with CSM with more severe developmental spinal canal stenosis at C7, accelerated degeneration at the caudal segment resulting from restricted C3-C6 ROM after C3-C6 laminoplasty might lead to LND.

Factors affecting postoperative activities of daily living in patients with osteoporotic vertebral collapse with neurological deficits.

Surgical treatment of osteoporotic vertebral collapse (OVC) with neurological deficits presents significant clinical challenges because some patients have fragile bones and often have medical comorbidities, which affect the severity of osteoporosis. We hypothesized that clinical results of surgery in these patients depend on the extent of medical comorbidities that induce secondary osteoporosis. The aim of this study is to examine the effects of medical history and comorbidities on surgical outcomes for these patients, along with the factors that predict postoperative function in activities of daily living (ADL). We retrospectively reviewed data for 88 patients with OVC and neurological deficits who underwent surgery. We assessed clinical results regarding neurological deficits and function in ADL. The presence or absence of comorbidities responsible for secondary osteoporosis and treatments or medical events that affect bone metabolism were examined. We performed statistical analysis to examine prognostic factors for postoperative function in ADL. Of 88 patients, the distributions of comorbidities, treatment, and events in medical history were as follows: hypertension, 57 patients (64.8%); chronic kidney disease (CKD) stage 3 or 4, 32 (36.4%); diabetes mellitus, 16 (18.2%); liver dysfunction, 11 (12.5%); cardiovascular disease, 10 (11.4%); rheumatoid arthritis, 9 (10.2%); and glucocorticoid intake, 8 (9.1%). Twenty-five patients (28.4%) represented poor postoperative ADL (chair-bound or bed-bound), and 11 of 25 patients with poor postoperative ADL represented full neurological recovery. Multivariate analysis revealed decreased estimated glomerular filtration rate (odds ratio 0.96; 95% confidence interval 0.93-0.99; p = 0.005) and a high serum alkaline phosphatase (ALP) level (odds ratio 1.01; 95% CI 1.00-1.02; p = 0.01) were strong predictive factors for poor postoperative function in ADL. The majority of patients with poor postoperative function in ADL had advanced CKD with a disorder of bone metabolism as well as bone fragility.

Modified posterior lumbar interbody fusion for radiculopathy following healed vertebral collapse of the middle-lower lumbar spine.

Study Design Retrospective study. Objectives Lumbar radiculopathy is rarely observed in patients who have achieved bony healing of vertebral fractures in the middle-lower lumbar spine. The objectives of the study were to clarify the clinical features of such radiculopathy and to evaluate the preliminary outcomes of treatment using a modified posterior lumbar interbody fusion (PLIF) procedure. Methods Fourteen patients with at least 2-year follow-up were enrolled in this study. The radiologic and clinical features of radiculopathy were retrospectively reviewed. As part of our modified PLIF procedure, a bone block was laid on chipped bone to fill the cavity of the fractured end plate and to flatten the cage-bone interface. Results The morphologic features of spinal deformity in our patients typically consisted of the intradiscal vacuum phenomenon, spondylolisthesis, and a retropulsed intervertebral disk with a vertebral rim in the damaged segment. Cranial end plate fracture resulted in radiculopathy of the traversing nerve roots due to lateral recess stenosis. On the other hand, caudal end plate fracture led to unilateral radiculopathy of the exiting nerve root due to foraminal stenosis. The mean recovery rate based on the Japanese Orthopaedic Association score was 65.0%. Solid fusion was achieved in all but one case. Conclusions Because of severe deterioration of the anterior column following end plate fracture, the foraminal zone must be decompressed in caudal end plate fractures. The modified PLIF procedure yielded satisfactory clinical outcomes due to anterior reconstruction and full decompression for both foraminal and lateral recess stenoses.

Cervical myelopathy caused by invagination of anomalous lamina of the axis.

The authors report a case of cervical myelopathy caused by invagination of the bilaterally separated lamina of the axis. They also present a literature review. The patient was a previously healthy 68-year-old man with a 1-year history of slowly progressive gait disturbance, right-hand clumsiness, and right dominant sensory disturbance in his trunk and extremities. Both MRI and CT showed that the spinal cord was markedly compressed at the C2-3 level, on the right side, by a deeply invaginated anomalous lamina of the axis. A bilaterally separated lamina was also visible. The patient underwent removal of the anomalous invaginated fragment of the separated lamina and the spinous process of the axis. One year after surgery, his myelopathic symptoms had almost completely resolved. Here, the authors present the case of a patient with an extremely rare anomaly of the lamina of the axis. The underlying pathogenesis of this anomaly could be the failure of the 2 chondrification centers on either side to fuse into a single ossification center. Surgical removal of the anomalous invaginated lamina produced a satisfactory outcome.

Steroid-induced paraparesis: spinal epidural lipomatosis complicated by a wedge deformity of the middle thoracic vertebrae.

Steroid therapy is commonly prescribed, although a variety of complications have been reported. Among such complications, spinal epidural lipomatosis is rare and difficult to diagnose before paraparesis occurs. The purpose of this report is to present a rare but catastrophic complication of steroid therapy. A 64-year-old woman undergoing long-term steroid therapy suffered from an osteoporotic vertebral compression fracture and was unable to walk due to paraparesis. Magnetic resonance imaging (MRI) demonstrated a D7 compression fracture and stored epidural adipose tissue between D5 and D8. After surgery, the patient was able to walk with double canes. This case indicates that long-term steroid use has the potential to induce paraparesis.

Surgical outcomes of additional posterior lumbar interbody fusion for adjacent segment disease after single-level posterior lumbar interbody fusion.

PURPOSE: Adjacent segment disease (ASD) is an increasing problematic complication following lumbar fusion surgeries. ASD requires appropriate treatment, although there are only few reports on surgery for ASD. This study aimed to clarify surgical outcomes of posterior lumbar interbody fusion (PLIF) for ASD. METHODS: Medical charts of 18 patients who underwent the second (repeat) PLIF for ASD were retrospectively investigated (average follow-up, 40 [27-66] months). Modified Japanese Orthopaedic Association (JOA) score and Whitecloud classification were used as outcome measures. RESULTS: Mean modified JOA score improved from 7.7 just before repeat PLIF to 11.4 at maximum recovery and declined to 10.2 at final follow-up. Mean recovery rate of modified JOA score was 52.9 % at maximum recovery and 31.6 % at final follow-up. According to Whitecloud classification, 17 patients (94 %) were excellent or good and only 1 was fair at maximum recovery, whereas 10 (56 %) were excellent or good, 6 were fair, and 2 were poor at final follow-up. Eight patients (44 %) deteriorated again because of recurrent ASD. Two poor patients underwent a third PLIF. CONCLUSION: PLIF is effective for ASD after PLIF in the short term, although it tends to lead to a high incidence of recurrent ASD.

Outcomes of 2-level posterior lumbar interbody fusion for 2-level degenerative lumbar spondylolisthesis.

OBJECT: A systematic review concerning surgical management of lumbar degenerative spondylolisthesis (DS) showed that a satisfactory clinical outcome was significantly more likely with adjunctive spinal fusion than with decompression alone. However, the role of adjunctive fusion and the optimal type of fusion remain controversial. Therefore, operative management for multilevel DS raises more complicated issues. The purpose of this retrospective study was to elucidate clinical and radiological outcomes after 2-level PLIF for 2-level DS with the least bias in determination of operative procedure. METHODS: Since 2005, all patients surgically treated for lumbar DS at the authors' hospital have been treated using posterior lumbar interbody fusion (PLIF) with pedicle screws, irrespective of severity of slippage, patient age, or bone quality. The authors conducted a retrospective review of 20 consecutive cases involving patients who underwent 2-level PLIF for 2-level DS and had been followed up for 2 years or longer (2-level PLIF group). They also analyzed data from 92 consecutive cases involving patients who underwent single-level PLIF for single-level DS during the same time period and had been followed for at least 2 years (1-level PLIF group). This second group served as a control. Clinical status was assessed using the Japanese Orthopaedic Association (JOA) score. Fusion status and sagittal alignment of the lumbar spine were assessed by comparing serial plain radiographs. Surgery-related complications and the need for additional surgery were evaluated. RESULTS: The mean JOA score improved significantly from 12.8 points before surgery to 20.4 points at the latest follow-up in the 2-level PLIF group (mean recovery rate 51.8%), and from 14.2 points preoperatively to 22.5 points at the latest follow-up in the single-level PLIF group (mean recovery rate 55.3%). At the final follow-up, 95.0% of patients in the 2-level PLIF group and 96.7% of those in the 1-level PLIF group had achieved solid spinal fusion, and the mean sagittal alignment of the lumbar spine was more lordotic than before surgery in both groups. Early surgery-related complications, including transient neurological complications, occurred in 6 patients in the 2-level PLIF group (30.0%) and 11 patients in the 1-level PLIF group (12.0%). Symptomatic adjacent-segment disease was found in 4 patients in the 2-level PLIF group (20.0%) and 10 patients in the 1-level PLIF group (10.9%). CONCLUSIONS: The clinical outcome of 2-level PLIF for 2-level lumbar DS was satisfactory, although surgery-related complications including symptomatic adjacent-segment disease were not negligible.

Surgical treatment for osteoporotic vertebral collapse with neurological deficits: retrospective comparative study of three procedures--anterior surgery versus posterior spinal shorting osteotomy versus posterior spinal fusion using vertebroplasty.

PURPOSE: In general, osteoporotic vertebral collapse (OVC) with neurological deficits requires sufficient decompression of neural tissues to restore function level in activities of daily living (ADL). However, it remains unclear as to which procedure provides better neurological recovery. The primary purpose of this study was to compare neurological recovery among three typical procedures for OVC with neurological deficits. Secondary purpose was to compare postoperative ADL function. METHODS: We retrospectively reviewed data for 88 patients (29 men and 59 women) with OVC and neurological deficits who underwent surgery. Three typical kinds of surgical procedures with different decompression methods were used: (1) anterior direct neural decompression and reconstruction (AR group: 27 patients), (2) posterior spinal shorting osteotomy with direct neural decompression (PS group: 36 patients), and (3) posterior indirect neural decompression and short-segment spinal fusion combined with vertebroplasty (VP group: 25 patients). We examined clinical results regarding neurological deficits and function level in ADL and radiological results. RESULTS: The mean improvement rates for neurological deficits and ADL function level were 60.1 and 55.0%, respectively. There were no significant differences among three groups in improvement rates for neurological deficits or ADL function level. The VP group had a significantly lower estimated mean blood loss (338 mL) and mean duration of surgery (229 min) than both the AR and PS groups (p < 0.001). CONCLUSION: Direct neural decompression is not always necessary, and the majority of patients can be treated with a less-invasive procedure such as short-segment posterior spinal fusion with indirect decompression combined with vertebroplasty. The high-priority issue is careful evaluation of patients' general health and osteoporosis severity, so that the surgeon can choose the procedure best suited for each patient.

Postoperative deep surgical-site infection after instrumented spinal surgery: a multicenter study.

A retrospective survey revealed 37 cases (1.1%) of deep surgical-site infection (SSI) among 3,462 instrumented spinal surgeries between 2004 and 2008. Excluding 8 patients who were unclassifiable, we categorized 29 patients into 3 groups of similar backgrounds-thoracolumbar degenerative disease (the DEG group; n = 15), osteoporotic vertebral collapse (the OVC group; n = 10), and cervical disorders (the cervical group; n = 4)-and investigated the key to implant salvage. Final respective implant retention rates for the groups were 40, 0, and 100%, with the OVC group having the worst rate (p < 0.01). In the DEG group with early infection, those whose implants were retained had lower body temperatures, lower white blood cell counts, and a lower rate of discharge at the time of SSI diagnosis (p < 0.05). Implant retention may be affected by initial spinal pathology. In the DEG group, debridement before drainage may be advantageous to implant salvage.