Physical Signs and Clinical Features of Cervical Myelopathy in Elderly Patients, Especially 80 Years or Older: Comparison of 100 Consecutive Operative Cases across Three Age Groups.

STUDY DESIGN: Retrospective cohort study. PURPOSE: The present study aimed to examine the characteristics of physical signs in elderly patients with cervical myelopathy (CM) and to compare the findings in three different age groups. OVERVIEW OF LITERATURE: As the global population ages, the incidence of CM in elderly patients is increasing. METHODS: We evaluated 100 consecutive surgical patients with CM and divided them into the following groups: 80s (34 patients; mean age, 83.9 years), 70s (33 patients; mean age, 73.9 years), and 69 or younger (33 patients; mean age, 60.9 years). The clinical symptoms and physical signs were evaluated and recorded. RESULTS: Although the recovery rate decreased with increasing age, all groups demonstrated a significant improvement in clinical symptoms relative to preoperative values. The Hoffman sign and hyperreflexia of the triceps tendon were, respectively, present in 82% and 88% of patients in the 80s group, 74% and 64% of those in the 70s group, and 69% and 82% of those in the 69 or younger group, with no significant difference among the groups. In contrast, the rates of hyperreflexia of the patellar and Achilles tendons were, respectively, 59% and 32% in the 80s group, 85% and 48% in the 70s group, and 91% and 70% in the 69 or younger group, with significant differences. CONCLUSIONS: The positivity rate of the lower extremity hyperreflexia decreased significantly with increasing age in patients with CM. The absence of hyperreflexia, particularly lower extremity, is not uncommon in elderly patients with suspected CM.

Incidence and trend of antiresorptive agent-related osteonecrosis of the jaw from 2016 to 2020 in Kure, Japan.

We investigated the incidence/trend of osteonecrosis of the jaw by antiresorptive agent dose over a 5-year period in Kure city, Japan. The incidence was 24 times higher among osteoporosis patients with low-dose agents and 421 times higher among cancer patients with high-dose agents than in the population without agents. PURPOSE: We launched the registry system of osteonecrosis of the jaw (ONJ) cases in 2015 to investigate the trend in ONJ incidence. The purpose of our study was to estimate the ONJ incidence among patients with antiresorptive agent use by dosage and people without antiresorptive agent use in Kure and its trend from 2016 to 2020. METHODS: From 2016 to 2021, 98 eligible ONJ patients were enrolled. Medication-related ONJ (MRONJ) was diagnosed based on the American Association of Oral and Maxillofacial Surgeons criteria. The annual number of those with and without antiresorptive agents was obtained from the claims database. Antiresorptive agents used for cancer and osteoporosis patients were defined as high- and low-dose medications, respectively. RESULTS: The annual incidence of high-dose MRONJ was 2305.8 per 100,000 and that of low-dose MRONJ was 132.5 per 100,000, while the ONJ incidence among people without antiresorptive agents was 5.1 per 100,000. The incidence ratio was 23.6 (p < 0.001, 95% confidence interval (CI) 13.3-41.8) among osteoporosis patients who used low-dose antiresorptive agents and 420.6 (p < 0.001, 95% CI 220.8-801.4) among cancer patients who used high-dose agents compared with people who did not use these agents. MRONJ incidence increased from 2016 to 2020, but the incidence of high-dose MRONJ decreased, although this was nonsignificant. CONCLUSION: We demonstrated the incidence and trend of ONJ by antiresorptive agent dose over a 5-year period in Kure after launching the multiprofession study. This collaborative study for the early detection and prevention of ONJ will continue.

Incomplete Atypical Femoral Fracture Treated by Prophylactic Intramedullary Nail Fixation: A Case Series.

Long-term bisphosphonate use may be associated with atypical femoral fractures. In this report, we describe three cases of bisphosphonate-associated incomplete atypical femoral fracture, treated by prophylactic intramedullary nail fixation. Patients with long-term intake of bisphosphonates must be carefully monitored; atypical femoral fracture should be suspected in the presence of symptoms such as thigh pain. Its early identification is important to avoid a complete fracture and invasive surgery, and prophylactic fixation is recommended for incomplete atypical femoral fractures.

Prognostic factors for spontaneous spinal epidural hematoma: a multicenter case-control study.

BACKGROUND: To determine the optimal treatment for spontaneous spinal epidural hematoma (SSEH). The aim of this study was to identify factors associated with SSEH. METHODS: In 62 patients with SSEH, several patient-related parameters were analyzed as candidate factors associated with Frankel grade before treatment or at the last follow-up. These parameters were compared between patients with and without surgery. In addition, multivariate ordinal logistic regression analysis was used to identify factors significantly associated with Frankel's grade before treatment or at the last follow-up. RESULTS: There were significant differences in age, location of the hematoma, and Frankel grade before treatment and at the last follow-up between surgical and nonsurgical cases in all patients, but there were no significant differences in any of these parameters when comparing patients with pre-treatment Frankel grade C. The location of the hematoma was significantly associated with the severity of paralysis before treatment. In surgical cases, the time from onset to surgery and the location of the hematoma was significantly associated with the prognosis. When the time from onset to surgery was evaluated using the criteria of 12, 24, and 48 h, 24 and 48 h had a significant impact on the prognosis. In the analysis of nonsurgical cases, only the vertical size of the hematoma was significantly associated with prognosis. CONCLUSION: The time from onset to surgery and the location of the hematoma were prognostic factors in surgical cases, while the vertical size of the hematoma was a prognostic factor in nonsurgical cases.

Incidence of fractures among patients receiving medications for type 2 diabetes or chronic obstructive pulmonary disease and glucocorticoid users according to the National Claims Database in Japan.

According to information from the National Health Insurance and Claims database, the risk for hip, radius, and clinical vertebral fractures was higher among patients receiving medication for type 2 diabetes, COPD, or glucocorticoids than among the whole Japanese population after middle age. PURPOSE: The aim of this study was to determine the incidence of fractures among patients receiving medications for type 2 diabetes or chronic obstructive pulmonary disease (COPD) and using glucocorticoids (GC) according to the National Database of Health Insurance Claims (NDB) in Japan. METHODS: We obtained data on the number of fractures and patients receiving medications for type 2 diabetes, COPD, or GC from the NDB. The claims data included sex, age group, injury/illness name, hospitalization, outpatient, surgery/medical treatment, and drugs used between January and December 2017. RESULTS: The risk of hip fracture was higher among patients receiving medications for diabetes or COPD and GC users than in the Japanese population, with standardized incidence ratios (SIRs) of 1.71 (95% confidence interval [CI]1.6-1.75), 1.35 (95% CI 1.28-1.42), and 1.62 (95% CI 1.53-1.71) in men and 1.81 (95% CI 1.79-1.84), 1.67 (95% CI 1.54-1.80), and 1.71 (95% CI 1.66-1.76) in women, respectively. There was also a significantly higher incidence of radial fractures in women and clinical vertebral fractures in both men and women. A greater risk of hip fracture was found among diabetic patients starting in their late 40 s. CONCLUSIONS: Real-world data revealed that the incidence of hip, radius, and clinical vertebral fractures was significantly higher among patients receiving medications for diabetes or COPD and GC users than in the Japanese population after middle age.

Incidence of clinical vertebral fractures and hip fractures of the elderly (65 years or over) population-large-scale data analysis using claim database in Kure City, Hiroshima, Japan.

Using the claim database, we investigated the incidence rate of clinical vertebral fractures per 1,000 in the elderly residents, over 65 years of age, in Kure city. The incidence rate, of clinical vertebral fractures, was 15.58 (7.29 male, 21.17 female, 2.90 female/male ratio). PURPOSE: To elucidate the incidence of clinical vertebral and hip fractures using the claim database, in those over 65 years of age in Kure city, and to compare with the previous reports. METHODS: We used, for residents in 2015, the medical care information of the National Health Insurance or Senior Elderly Care System in Kure City (Hiroshima Prefecture, Japan). Those with vertebral fractures as disease name, and either treatment/operation/hospitalization were defined as clinical vertebral fractures. Among the claim database, we extracted the clinical vertebral fracture and investigated the number of occurrences and the incidence rate per 1,000. We also investigated the incidence rate of hip fractures and compared those to the clinical vertebral fractures. RESULT: The incidence rate of clinical vertebral fractures of the elderly population (65 years or over) per 1,000 was 15.58 (7.29 male, 21.17 female, 2.90 female/male ratio). In both men and women, the incidence rate increased with aging. The incidence rate of hip fractures per 1,000 was 9.17 (3.55 male, 12.96 female, 3.65 male/female ratio). Clinical vertebral fractures were more frequent than hip fractures, and the ratio of incidence rate of vertebral fractures to hip fractures was 1.70 (male, 2.05, female, 1.63). For both fractures, the incidence rate increases with age, apart from the women where the incidence of vertebral fracture reduces slightly in the older age group CONCLUSION: This is the first report that investigated the incidence rate of the clinical vertebral fractures using the claim database, which covered almost the whole number of 230,000 population area.

Microscopic Posterior Transdural Resection of Cervical Retro-Odontoid Pseudotumors.

Retro-odontoid pseudotumors are noninflammatory masses formed posterior to the odontoid process. Because of their anatomy, the optimal surgical approach for resecting pseudotumors is controversial. Conventionally, 3 approaches are used: the anterior transoral approach, the lateral approach, and the posterior extradural approach; however, each approach has its limitations. The posterior extradural approach is the most common; however, it remains challenging due to severe epidural veins. Although regression of pseudotumors after fusion surgery has been reported, direct decompression and a pathologic diagnosis are ideal when the pseudotumor is large. We therefore developed a new microscopic surgical technique; transdural resection. After C1 laminectomy, the dorsal and ventral dura was incised while preserving the arachnoid. Removal of the pseudotumor was performed and both of the dura were repaired. The patient's clinical symptoms subsequently improved and the pathologic findings showed degenerative fibrocartilaginous tissue. In addition, no neurological deterioration, central spinal fluid leakage, or arachnoiditis was observed. Currently, the usefulness of the transdural approach has been reported for cervical and thoracic disk herniation. According to our results, the transdural approach is recommended for resection of retro-odontoid pseudotumors because it enables direct decompression of the spinal cord and a pathologic diagnosis.

The effect of pedicle screw redirection after lateral wall breach--a biomechanical study using human lumbar vertebrae.

BACKGROUND CONTEXT: Currently, pedicle screw segmental fixation of the spine is considered a standard of care for a number of conditions. Most surgeons employ a free-hand technique using various intraoperative modalities to improve pedicle screw accuracy. Despite continued improvements in technique, pedicle breach remains a frequent occurrence. Once a breach is detected intraoperatively, the most common corrective maneuver is to medially redirect the pedicle screw into the pedicle. To our knowledge, the biomechanical impact of medially redirecting a pedicle screw after a lateral pedicle breach has not been examined. PURPOSE: To compare the fixation strength of perfectly placed pedicle screws to the fixation strength of pedicle screws that were correctly placed after having been redirected (RD) following a lateral pedicle breach. STUDY DESIGN/SETTING: A biomechanical study using human lumbar vertebrae. METHODS: Ten fresh human lumbar vertebrae were isolated from five donors. Each vertebra was instrumented with a monoaxial pedicle screw into each pedicle using two different techniques. On one side, a perfect center-center (CC) screw path was created using direct visualization and fluoroscopy. A 6.0-mm-diameter cannulated tap and a pedicle probe were used to develop the pedicle for the 7.0-mm-diameter by 45-mm-long cannulated pedicle screw, which was placed using a digital torque driver. On the contralateral side, an intentional lateral pedicle wall breach was created at the pedicle-vertebral body junction using a guide wire, a 6.0-mm-diameter cannulated tap, and a pedicle probe. This path was then redirected into a CC position, developed, and instrumented with a 7.0-mm-diameter by 45-mm-long cannulated pedicle screw: the RD screw. For each pedicle screw, we assessed four outcome measures: maximal torque, seating torque, screw loosening, and post-loosening axial pullout. Screw loosening and axial pullout were assessed using an MTS machine. RESULTS: The biomechanical cost of a lateral pedicle breach and the requirement to redirect the pedicle screw are as follows: an overall drop of 28% (p<.002) in maximal insertion torque and 25% (p<.049) in seating torque, a drop of 25% (p<.040) in resistance to screw loosening, and a drop in axial pullout force of 11% (p<.047). CONCLUSIONS: Compared with a CC lumbar pedicle screw, an RD lumbar pedicle screw placed after a lateral wall breach is significantly weaker in terms of maximal insertional torque, seating torque, screw loosening force, and axial pullout strength. These significant decreases in biomechanical properties are clearly important when RD pedicle screws are placed at the cephalad or caudal end of a long construct. In this situation, augmentation of the RD screw is an option.

Surgical treatment of high-grade dysplastic spondylolisthesis using intraoperative electrophysiological monitoring: report of two cases and review of the literature.

Treatment of high-grade dysplastic spondylolisthesis in adolescents remains challenging. Surgical treatment of spondylolisthesis has been recommended in adolescents with pain refractory to conservative treatment, slippage progression, or severe slippage on presentation. Controversy exists as to the optimal surgical approach for high-grade spondylolisthesis. Moreover, some authors reported the incidence of L5 root palsy during the reduction procedure. We performed 2 cases of surgical treatment using intraoperative electrophysiological monitoring for patients with high-grade dysplastic spondylolisthesis in adolescence. Each patient received treatment consisting of decompression of nerve with surgical microscope, reduction, and circumferential fusion with transpedicular and monosegmental fixation surgery with intraoperative neurological monitoring with transcranial electric motor evoked potentials and continuous spontaneous electromyography recording. Intraoperative monitoring did not show any abnormal changes. The patients got well after surgery, and they showed no postoperative motor paralysis of the extremities. A postoperative radiogram showed reduction of the slippage, and computed tomogram showed bone union between L5 and S1 vertebral body. This report describes 2 cases of surgical treatment using intraoperative electrophysiological monitoring with transcranial electric motor evoked potentials and continuous spontaneous electromyography for patients with high-grade dysplastic spondylolisthesis in adolescence. We successfully perform the surgery without any neurological deficit using intraoperative electrophysiological monitoring.

Therapeutic effects with magnetic targeting of bone marrow stromal cells in a rat spinal cord injury model.

STUDY DESIGN: Experimental rat animal study using a new cell delivery system. OBJECTIVE: To investigate the therapeutic effects with magnetic targeting of bone marrow stromal cells (BMSCs) in a rat spinal cord injury (SCI) model. SUMMARY OF BACKGROUND DATA: Several methods to deliver therapeutic agents have been used for the treatment of SCI in animal studies. However, the most appropriate administration method for clinical application has not been established. Previously, we reported the development of a new cell delivery system using magnetic targeting. This system has potential as a clinical application for a minimally invasive and efficient transplant method in SCI. METHODS: Contusion SCI was induced by placing a 25 g rod onto the spinal cord for 90 seconds in adult SD rats. A neodymium magnet was placed in the paravertebral muscles at the T7 level in the magnet group, whereas a nonmagnet metal was placed at the same spinal cord level in the nonmagnet group. Magnetically labeled BMSCs were injected into the subarachnoid space in both the magnet and nonmagnet group. RESULTS: Aggregations of the BMSCs were detected on the surface of the injured spinal cord in the magnet group, whereas few BMSCs were observed in the nonmagnet group. Hindlimb motor function of the magnet group demonstrated significant improvement compared with that of the nonmagnet group. CONCLUSION: This cell delivery system may be a useful method for future clinical application in the treatment of SCI.

Plate-only open door laminoplasty maintains stable spinal canal expansion with high rates of hinge union and no plate failures.

STUDY DESIGN: Prospective clinical series. OBJECTIVE: To evaluate the ability of plate-only laminoplasty to achieve stable laminar arch reconstruction and to determine the rate and time course with which bony healing occurs in such constructs. SUMMARY OF BACKGROUND DATA: Reconstruction of a stable laminar arch with sufficient room for the decompressed spinal cord is a desired goal when performing cervical laminoplasty for myelopathy. Traditional forms of laminoplasty fixation, such as sutures, bone struts, and ceramic spacers, may be associated with complications including loss of fixation, dislodgement with neurologic compromise, and premature laminoplasty closure. Plates, in contrast, provide more rigid fixation. Plate-only laminoplasty is gaining popularity as a method of laminoplasty fixation, but there is little data on its effectiveness. METHODS: Fifty-four patients who underwent open door laminoplasty for cervical myelopathy and had available postoperative computed tomography (CT) scans formed the basis of this study. In all cases, a 4-mm round burr was used to create the hinge at the junction of the lateral mass and lamina by completely removing the dorsal cortex and thinning the ventral cortex until a greenstick deformation of the hinge could be produced. Laminoplasty plates were used as the sole method of fixation. No supplemental bone graft struts were used on the plated side, and the hinge side was not bone grafted. Axial CT scans obtained at 3, 6, and 12 months postoperatively were assessed for plate complications and bony healing of the hinge. RESULTS: No plate failures, dislodgements, or premature closures occurred in any of the levels at any time postoperatively. Computed tomography scan review demonstrated that 55% of levels were healed at 3 months, 77% at 6 months, and 93% at 12 months. At each timepoint, C6 and C7 had the highest hinge healing rates. Laminar screw backout was seen in 5/217 (2.3%) of levels, but was not associated with plate dislodgement, laminoplasty closure, or neurologic consequences, and did not occur in any case in which 2 laminar screws had been placed. CONCLUSION: Plate-only laminoplasty provided stable reconstruction of an expanded laminar arch with no failures, dislodgements, adverse neurologic consequences, or premature closures in 217 levels. Ninety-three percent of hinges demonstrated radiographic union at 12 months, and even those that did not heal by CT scan criteria maintained patent expansion of the spinal canal without adverse neurologic consequences. Supplemental bone graft does not appear necessary when plated laminoplasty is performed.

Assessment of central motor conduction time in the diagnosis of compressive thoracic myelopathy.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: The objective of this study was to investigate central motor conduction time (CMCT) values in patients with compressive thoracic myelopathy (CTM) and analyze its power to diagnose this condition. SUMMARY OF BACKGROUND DATA: CTM is rare and its diagnosis is often difficult, when other spinal disorders such as cervical or lumbar degenerative spondylosis supervene. Measurement of CMCT following transcranial magnetic stimulation is a useful means to evaluate the electrophysiological functions of the corticospinal tract; however, there are few reports describing CMCT values among patients with CTM. METHODS: Motor-evoked potentials following transcranial magnetic stimulation, and compound muscle action potentials and F-waves following electrical stimulation in the ulnar and tibial nerves were measured from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles in 20 patients with CTM, 92 patients with compressive cervical myelopathy (CCM), and 18 control subjects. The CMCT detected from the ADM (CMCT-ADM), the AH (CMCT-AH), and the CMCT-ADM/AH ratio (CMCT-ADM/CMCT-AH) were calculated. RESULTS: The CMCT-AHs in patients with CTM were significantly longer than in control subjects, although there were no significant differences in the CMCT-ADMs. In contrast, both the CMCT-ADMs and CMCT-AHs in the CCM group were significantly longer than those of the control group. The CMCT-ADM/AH ratios in the CTM group were significantly lower than those of the other groups. Among the CTM and CCM groups, when the cutoff point of the CMCT-ADM/AH ratio was set at equal to or lower than 0.52, i.e., the mean CMCT-ADM/AH ratio in the control group, the odds ratio for CTM was 68.4 (95% confidence interval: 8.62-543; P < 0.001). CONCLUSION: Our data showed a significant pattern of CMCT parameters and low CMCT-ADM/AH ratios in patients with CTM. The measurement of CMCT is valuable as a noninvasive technique for screening patients with CTM or CCM before magnetic resonance imaging.

Do the adjacent level intervertebral discs degenerate after a lumbar spinal fusion? An experimental study using a rabbit model.

STUDY DESIGN: A rabbit model of disc degeneration adjacent to a lumbar spinal fusion. OBJECTIVE: To use a rabbit model to determine the long-term changes in the intervertebral discs at the levels above (cephalad) and below (caudad) 2 fused lumbar levels. SUMMARY OF BACKGROUND DATA: Lumbar spinal fusion is generally carried out to eliminate motion at a specific lumbar level. However, it is commonly thought that by eliminating motion at a level, one increases the motion at the adjacent levels cephalad and caudad the fused levels. There have been studies that have reported on degeneration occurring at the cephalad and caudad levels adjacent to the fused levels. METHODS: A total of 9 New Zealand white, female rabbits: 4 rabbits in the control group and 5 rabbits in the experimental group. The 5 rabbits in the experimental group underwent a posterolateral 2-level lumbar spinal fusion from L3 to L5. The changes in the lumbar discs were assessed using radiographs, magnetic resonance (MR) images, and histology at 6 months and 12 months. RESULTS: The results at 6 months are less clear than those at 12 months. The results at 12 months for the experimental group are (1) the intervertebral disc height decreased at the caudad adjacent level and to a lesser extent at the cephalad adjacent level; (2) the MRI scores for the discs at the caudad and cephalad adjacent levels showed severe loss of signal intensity as compared to the discs at the same levels in the control group. This loss was more pronounced at the caudad level where the loss of signal intensity was similar to that seen at the fused levels; (3) the histologic analysis showed severe degenerative changes with a lack of live cells in the nucleus pulposus and in the endplate at the caudad adjacent level. At the cephalad level, live cells were apparent (albeit few) in the nucleus pulposus, and there was a more normal looking endplate with live cells. CONCLUSION: The intervertebral discs at both the cephalad and the caudad levels adjacent to the 2 fused lumbar levels in this rabbit-model experiment carried out over 12 months after surgery showed degenerative changes asassessed using disc-height measurements, MR images, and histology, and the effect was more severe at the caudad adjacent level.

The effects of combining chondroitinase ABC and NEP1-40 on the corticospinal axon growth in organotypic co-cultures.

The area surrounding the injured spinal cord is a non-permissive milieu for axonal growth due to the inhibitory factors, especially chondroitin sulfate proteoglycan (CSPG) and Nogo. Recent studies have reported that chondroitinase ABC (ChABC) or Nogo-66(1-40) antagonist peptide (NEP1-40) promote axonal growth after spinal cord injury. But no study has addressed the effects on spinal cord injury of combining ChABC and NEP1-40. Previously, we described an organotypic co-culture system using the brain cortex and spinal cord from neonatal rats. In this study, we examined whether the combination of ChABC and NEP1-40 creates an action that promotes corticospinal axon growth in organotypic co-cultures. Organotypic co-cultures of brain and spinal cord were prepared from rats, and ChABC or NEP1-40 was delivered to them. To examine the effects of this combination these two drugs were applied together. We counted the number of labeled axons with DiI and assessed the immunoreactivity of CSPG and Nogo. Axonal growth was enhanced by infusing ChABC or NEP1-40 compared with that in the control group, whereas synergistic effects of combined administration of ChABC and NEP1-40 on axonal growth were not observed. There is a possibility that ChABC and NEP1-40 affect the same intracellular pathways and have no synergistic influence on axonal growth.

Spinal instrumentation for sacral-pelvic fixation: a biomechanical comparison between constructs ending with either S2 bicortical, bitriangulated screws or iliac screws.

STUDY DESIGN: A biomechanical study of 2 fixation techniques for lumbosacral fixation. OBJECTIVE: To evaluate 2 techniques, one using S1 screws combined with bicortical, bitriangulated (BCBT) S2 screws, and the other using S1 screws combined with iliac screws. SUMMARY OF BACKGROUND DATA: Common to the 2 techniques of sacral-pelvic fixation is S1 pedicle screws; the difference lies between S2 screws versus iliac screws. Iliac screws are clinically effective, yet present clinical disadvantages that S2 screws can potentially obviate, for example, wide dissection, soft tissue coverage, crossing the sacroiliac joint, and interference with bone graft harvesting. In an effort to optimize S2 fixation, we have used a BCBT S2 technique. METHODS: Eight fresh human sacral-pelvic specimens were harvested (average age 78.7 y; bone density 0.75 g/cm2). Screws were placed bilaterally: (1) at S1: 7.5 mm diameter screws were placed bicortical; (2) at S2: 7.5 mm diameter by 60 mm long screws were placed bicortical and bitriangulated; (3) the ilium received 7.5 mm diameter by 80-mm-long screws. Sacral-pelvic constructs were assembled and biomechanical stiffness testing was performed. The stiffness in each loading mode was calculated. After the stiffness tests were completed, each BCBT S2 screw and each iliac screw were individually loaded to determine fixation strength of each type of screw. RESULTS: There was no significant difference in stiffness between the 2 constructs, although S1 and the BCBT S2 construct tended to be stiffer in all modes. However, for the fixation strength of screws, the iliac screws loosened at loads that were significantly greater than those for BCBT S2 screws (c.f. 435.9 N with 144.7 N). CONCLUSIONS: Iliac screws maybe the better choice in cases with poor bone quality. However, the S1-BCBT-S2 screw construct is biomechanically an appropriate alternative to the S1-iliac screw construct and it presents clinical advantages.

Pedicle screw augmentation with polyethylene tape: a biomechanical study in the osteoporotic thoracolumbar spine.

STUDY DESIGN: Biomechanical study using human thoracolumbar spines. OBJECTIVE: To assess the strength of fixation of pedicle screws augmented with Nesplon tape applied sublaminar or applied subpars. SUMMARY OF BACKGROUND DATA: There are no reports on the biomechanical assessment of Nesplon tape used for pedicle screw augmentation. METHODS: Experiment 1: pedicle screws were inserted into bilateral pedicles as follows: (1) pedicle screw alone connected to a rod (PS alone), (2) pedicle screw augmented with Nesplon tape applied sublaminar, connected to a rod [pedicle screw applied sublaminar (PSSL)], and (3) pedicle screw augmented with tape applied subpars, connected to a rod [pedicle screw applied subpars (PSSP)]. The rods were pulled and pushed until the pedicle screw was loose. Experiment 2: 6 thoracolumbar spines were biomechanically tested as follows: axial compression, flexion, extension, left and right lateral bending, and left and right axial rotation. This sequence was applied to: (1) the intact spine; (2) the spine made unstable; (3) the spine fixed by pedicle screws and rods (PS alone); (4) the same as 3, but with the pedicle screws augmented using Nesplon tape applied sublaminar (PSSL); and (5) the same as 3, but with pedicle screws augmented using tape applied subpars (PSSP). From the load-deformation curves, stiffness values were calculated. RESULTS: Experiment 1: the pedicle screws augmented by sublaminar or subpars tape (PSSL or PSSP) showed significantly greater fixation strength compared with those pedicles that were not augmented by tape (PS alone). Experiment 2: a pedicle screw/rod construct augmented by tape provided a stiffer construct than the same construct without augmentation. CONCLUSIONS: Pedicle screws that are inserted into the osteoporotic thoracolumbar spine and augmented by Nesplon tape applied sublaminar or subpars provide firmer fixation of the screws and a stiffer pedicle screw/rod construct than the same construct without augmentation by tape.

Quantitative assessment of myelopathy patients using motor evoked potentials produced by transcranial magnetic stimulation.

Motor evoked potentials (MEPs) study using transcranial magnetic stimulation (TMS) may give a functional assessment of corticospinal conduction. But there are no large studies on MEPs using TMS in myelopathy patients. The purpose of this study is to confirm the usefulness of MEPs for the assessment of the myelopathy and to investigate the use of MEPs using TMS as a screening tool for myelopathy. We measured the MEPs of 831 patients with symptoms and signs suggestive of myelopathy using TMS. The MEPs from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles were evoked by transcranial magnetic brain stimulation. Central motor conduction time (CMCT) is calculated by subtracting the peripheral conduction time from the MEP latency. Later, 349 patients had surgery for myelopathy (operative group) and 482 patients were treated conservatively (nonoperative group). CMCTs in the operative group and nonoperative group were assessed. MEPs were prolonged in 711 patients (86%) and CMCTs were prolonged in 493 patients (59%) compared with the control patients. CMCTs from the ADM and AH in the operative group were significantly more prolonged than that in the nonoperative group. All patients in the operative group showed prolongation of MEPs or CMCTs or multiphase of the MEP wave. MEP abnormalities are useful for an electrophysiological evaluation of myelopathy patients. Moreover, MEPs may be effective parameters in spinal pathology for deciding the operative treatment.

Clinical results of cervical myelopathy in patients older than 80 years of age: evaluation of spinal function with motor evoked potentials.

OBJECT: In this prospective analysis the authors describe the clinical results of surgical treatment in patients > 80 years of age in whom spinal function was evaluated with motor evoked potential (MEPs) monitoring. METHODS: The authors included 57 patients > 80 years of age who were suspected of having cervical myelopathy. The mean age of the patients was 83.0 years (range 80-90 years). The central motor conduction time (CMCT) was calculated from the latencies of the MEPs following transcranial magnetic stimulation and from M and F waves following peripheral nerve stimulation. RESULTS: Preoperative electrophysiological evaluation demonstrated significant elongation of CMCT or abnormalities in MEP waveforms in 37 patients (65%), and 35 patients of these underwent laminoplasty. In 30 patients cervical spondylotic myelopathy was diagnosed and 5 patients ossification of the posterior longitudinal ligament was diagnosed. The preoperative mean Japanese Orthopaedic Association Scale score was 8.6 (range 3-12.5) and the mean postoperative score was 12.6 (range 6-14.5) with an average recovery rate of 45% (range -21 to 100%). There were no major complications in any of the patients during the operative period and there were no cases of death resulting from operative intervention. CONCLUSIONS: Sufficient clinical results are expected even in patients with myelopathy who are older than 80 years of age, provided the patients are correctly selected by electrophysiological evaluation with MEPs and CMCT.

Prevalence of physical signs in cervical myelopathy: a prospective, controlled study.

STUDY DESIGN: Prospective case-control study. OBJECTIVE: To determine the prevalence and utility of commonly tested myelopathic signs in surgically treated patients with cervical myelopathy (CM). SUMMARY OF BACKGROUND DATA: Although physical signs are sought in making the diagnosis of CM, their importance remains unclear, as patients with CM may have normal examinations while those without CM can demonstrate "myelopathic" signs. METHODS: Patients presenting with cervical complaints and advanced imaging were evaluated over a 6-month interval in a single surgical practice. The CM group consisted of those with (1) a history of myelopathic symptoms and (2) correlative spinal cord compression on imaging, who then (3) underwent surgery and (4) improved Nurick score by > or = 1 grade after surgery. The controls consisted of patients with neck/radicular complaints but no myelopathic symptoms and no cord compression on imaging. Myelopathic signs included hyperreflexia or provocative signs (Hoffman inverted brachioradialis reflex, clonus, Babinski). RESULTS: There were 39 CM patients and 37 controls. Myelopathic signs were more prevalent in the CM group (79% vs. 57%; P = 0.05), with significantly higher rates of all provocative signs but not hyperreflexia. Overall, myelopathic signs were not highly sensitive in diagnosing the presence of CM, as 21% of CM patients failed to demonstrate any myelopathic signs. There was no correlation between the presence of myelopathic signs and diabetes or preoperative Nurick score. However, those with cord signal changes were significantly more likely to demonstrate myelopathic signs. CONCLUSION: Although myelopathic signs are significantly more common in CM patients, they may be negative in approximately one-fifth and can not be relied on to make the diagnosis. In patients who lack myelopathic signs but otherwise seem myelopathic with no alternative explanations, symptoms combined with correlative imaging studies must be used to base treatment decisions, as the absence of signs does not preclude the diagnosis of myelopathy nor its successful surgical treatment.