White matter microstructural alterations in patients with neuropathic pain after spinal cord injury: a diffusion tensor imaging study.

Background: Through contrastive analysis, we aimed to identify the white matter brain regions that show microstructural changes in patients with neuropathic pain (NP) after spinal cord injury (SCI). Methods: We categorized patients with SCI into NP (n = 30) and non-NP (n = 15) groups. We extracted diffusion tensor maps of fractional anisotropy (FA) and mean (MD), axial (AD), and radial (RD) diffusivity. A randomization-based method in tract-based spatial statistics was used to perform voxel-wise group comparisons among the FA, MD, AD, and RD for nonparametric permutation tests. Results: Atlas-based analysis located significantly different regions (p < 0.05) in the appointed brain atlas. Compared to the non-NP group, the NP group showed higher FA in the posterior body and splenium of the corpus callosum and higher AD in the corpus callosum, internal capsule, corona radiata, posterior thalamic radiation, sagittal stratum, external capsule, cingulum, fornix/stria terminalis, superior longitudinal fasciculus, and uncinate fasciculus. Conclusion: The results demonstrated that compared with the non-NP group, NP pathogenesis after SCI was potentially related to higher values in FA that are associated with microstructural changes in the posterior body and splenium of the corpus callosum, which could be regarded as central sensitization or network hyperexcitability.

Chemometrics Approach Based on Wavelet Transforms for the Estimation of Monomer Concentrations from FTIR Spectra.

Fourier-transform infrared (FTIR) spectroscopy can detect the presence of functional groups and molecules directly from a mixed solution of organic molecules. Although it is quite useful to monitor chemical reactions, quantitative analysis of FTIR spectra becomes difficult when various peaks of different widths overlap. To overcome this difficulty, we propose a chemometrics approach to accurately predict the concentration of components in chemical reactions, yet interpretable by humans. The proposed method first decomposes a spectrum into peaks with various widths by the wavelet transform. Subsequently, a sparse linear regression model is built using the wavelet coefficients. Models by the method are interpretable using the regression coefficients shown on Gaussian distributions with various widths. The interpretation is expected to reveal the relation of broad regions in spectra to the model prediction. In this study, we conducted the prediction of monomer concentration in copolymerization reactions of five monomers against methyl methacrylate by various chemometric approaches including conventional methods. A rigorous validation scheme revealed that the proposed method overall showed better predictive ability than various linear and non-linear regression methods. The visualization results were consistent with the interpretation obtained by another chemometric approach and qualitative evaluation. The proposed method is found to be useful for calculating the concentrations of monomers in copolymerization reactions and for the interpretation of spectra.

Quantum chemistry simulation of ground- and excited-state properties of the sulfonium cation on a superconducting quantum processor.

The computational description of correlated electronic structure, and particularly of excited states of many-electron systems, is an anticipated application for quantum devices. An important ramification is to determine the dominant molecular fragmentation pathways in photo-dissociation experiments of light-sensitive compounds, like sulfonium-based photo-acid generators used in photolithography. Here we simulate the static and dynamical electronic structure of the H3S+ molecule, taken as a minimal model of a triply-bonded sulfur cation, on a superconducting quantum processor of the IBM Falcon architecture. To this end, we generalize a qubit reduction technique termed entanglement forging or EF [A. Eddins et al., Phys. Rev. X Quantum, 2022, 3, 010309], currently restricted to the evaluation of ground-state energies, to the treatment of molecular properties. While in a conventional quantum simulation a qubit represents a spin-orbital, within EF a qubit represents a spatial orbital, reducing the number of required qubits by half. We combine the generalized EF with quantum subspace expansion [W. Colless et al., Phys. Rev. X, 2018, 8, 011021], a technique used to project the time-independent Schrodinger equation for ground- and excited-states in a subspace. To enable experimental demonstration of this algorithmic workflow, we deploy a sequence of error-mitigation techniques. We compute dipole structure factors and partial atomic charges along ground- and excited-state potential energy curves, revealing the occurrence of homo- and heterolytic fragmentation. This study is an important step towards the computational description of photo-dissociation on near-term quantum devices, as it can be generalized to other photodissociation processes and naturally extended in different ways to achieve more realistic simulations.

Analytical Formulation of the Second-Order Derivative of Energy for the Orbital-Optimized Variational Quantum Eigensolver: Application to Polarizability.

We develop a quantum-classical hybrid algorithm to calculate the analytical second-order derivative of the energy for the orbital-optimized variational quantum eigensolver (OO-VQE), which is a method to calculate eigenenergies of a given molecular Hamiltonian by utilizing near-term quantum computers and classical computers. We show that all quantities required in the algorithm to calculate the derivative can be evaluated on quantum computers as standard quantum expectation values without using any ancillary qubits. We validate our formula by numerical simulations of quantum circuits for computing the polarizability of the water molecule, which is the second-order derivative of the energy, with respect to the electric field. Moreover, the polarizabilities and refractive indices of thiophene and furan molecules are calculated as a test bed for possible industrial applications. We finally analyze the error scaling of the estimated polarizabilities obtained by the proposed analytical derivative versus the numerical derivative obtained by the finite difference. Numerical calculations suggest that our analytical derivative requires fewer measurements (runs) on quantum computers than the numerical derivative to achieve the same fixed accuracy.

Suppression of Charge Recombination by Auxiliary Atoms in Photoinduced Charge Separation Dynamics with Mn Oxides: A Theoretical Study.

Charge separation is one of the most crucial processes in photochemical dynamics of energy conversion, widely observed ranging from water splitting in photosystem II (PSII) of plants to photoinduced oxidation reduction processes. Several basic principles, with respect to charge separation, are known, each of which suffers inherent charge recombination channels that suppress the separation efficiency. We found a charge separation mechanism in the photoinduced excited-state proton transfer dynamics from Mn oxides to organic acceptors. This mechanism is referred to as coupled proton and electron wave-packet transfer (CPEWT), which is essentially a synchronous transfer of electron wave-packets and protons through mutually different spatial channels to separated destinations passing through nonadiabatic regions, such as conical intersections, and avoided crossings. CPEWT also applies to collision-induced ground-state water splitting dynamics catalyzed by Mn4CaO5 cluster. For the present photoinduced charge separation dynamics by Mn oxides, we identified a dynamical mechanism of charge recombination. It takes place by passing across nonadiabatic regions, which are different from those for charge separations and lead to the excited states of the initial state before photoabsorption. This article is an overview of our work on photoinduced charge separation and associated charge recombination with an additional study. After reviewing the basic mechanisms of charge separation and recombination, we herein studied substituent effects on the suppression of such charge recombination by doping auxiliary atoms. Our illustrative systems are X-Mn(OH)2 tied to N-methylformamidine, with X=OH, Be(OH)3, Mg(OH)3, Ca(OH)3, Sr(OH)3 along with Al(OH)4 and Zn(OH)3. We found that the competence of suppression of charge recombination depends significantly on the substituents. The present study should serve as a useful guiding principle in designing the relevant photocatalysts.

[Two Cases of Venous Malformation of the Orbit Treated by Endoscopic Endonasal Surgery].

Venous malformation of the orbit(VMO), previously called orbital cavernous hemangioma, has been classified as a vascular malformation according to the International Society for the Study of Vascular Anomalies. Among various surgical approaches for VMO, endoscopic endonasal surgery(EES)has recently been developed, especially for those in the inferomedial quadrant of the orbit. Two 67-year-old and 69-year-old women presented with decreased visual acuity and visual field deficit, respectively. Their CT and MRI scans revealed retrobulbar masses, suggestive of the inferomedial type of VMO. The first case was diagnosed as an intraconal VMO, and subtotal removal was achieved through binostril EES using a two-surgeon four-handed technique after palliative partial resection through a prior frontal craniotomy. In the second case, diagnosed as an extraconal VMO, total en bloc removal was achieved using the same surgical technique as above. In both cases, the visual functions improved after the procedures, with uneventful postoperative courses. Although the inferomedial VMO is an uncommon type, EES is well indicated for this condition. The international consensus of surgical techniques and staging from a surgical point of view should be established in the near future.

Conservative and Surgical Management of Spinal Cord Cavernous Malformations.

OBJECTIVES: We present a case series of spinal cord cavernous malformations (SCCMs) to describe clinical presentation and outcomes of both surgical and conservative management. METHODS: The clinical courses of patients diagnosed with SCCMs at our institution were retrospectively reviewed. Neurologic symptoms were evaluated using the Modified McCormick Scale. RESULTS: A total of 18 patients were identified. Five patients (27.8%) presented with acute onset bleeding, 4 of whom underwent immediate surgical resection. Thirteen patients (72.2%) were initially managed conservatively. Eight patients (38.9%) developed a hemorrhage during follow-up, and 8 (38.9%) required surgical resection due to bleeding or neurological worsening. The mean (range) duration from primary symptoms to subsequent hemorrhage or deterioration of symptoms was 1.42 (range: 0.25-4.33) years. The mean duration from primary symptoms to surgery was 2.10 (range: 0.25-5.0) years. No patients experienced subsequent hemorrhage after surgical resection. Eleven patients (84.6%) in the surgery group showed improved neurological status, and 2 patients (15.4%) remained unchanged. The annualized subsequent hemorrhage risk was 3.7%. Patients in the immediate surgical group had a significantly larger lesion compared with those in the conservative group. There was significance between the worst Modified McCormick Scale grades at the time of debilitating symptoms and the length of hemorrhage, but not the size of the lesion. CONCLUSIONS: Surgery for SCCMs resulted in no recurrence of hemorrhage or exacerbation of neurological symptoms, and should be considered for patients who experienced acute onset of hemorrhage or debilitating symptoms during follow-up.

A Sufficient Surgical Window for Deep-Seated Extracranial Schwannomas in the Craniocervical Junction by the Anterolateral Approach.

Care should be taken regarding surrounding anatomic structures during access to deepseated extracranial schwannomas in the craniocervical junction (CCJ). Herein, we present surgical tips for extracranial schwannomas in the CCJ using the anterolateral approach. A retrospective review was performed of 3 cases of surgical treatment of extracranial schwannomas in the CCJ by the anterolateral approach, which is a presternomastoid retrojugular route to the CCJ. The combination of neck rotation and reflection of the sternocleidomastoid muscle presented a sufficient, shallow surgical field for the CCJ. We could identify tumors along the accessory nerves and internal jugular veins, and had sufficient rostrocaudal working space to resect the tumors. Two cases were enucleated total resection and 1 was subtotal resection. Two patients experienced transient postoperative vocal cord partial paralysis and 1 had transient dysphagia. These neurological complications improved within 1 month. The anterolateral approach can provide a shallow and sufficient rostral and caudal surgical window.

Perspective: Explicitly correlated electronic structure theory for complex systems.

The explicitly correlated approach is one of the most important breakthroughs in ab initio electronic structure theory, providing arguably the most compact, accurate, and efficient ansatz for describing the correlated motion of electrons. Since Hylleraas first used an explicitly correlated wave function for the He atom in 1929, numerous attempts have been made to tackle the significant challenges involved in constructing practical explicitly correlated methods that are applicable to larger systems. These include identifying suitable mathematical forms of a correlated wave function and an efficient evaluation of many-electron integrals. R12 theory, which employs the resolution of the identity approximation, emerged in 1985, followed by the introduction of novel correlation factors and wave function ansätze, leading to the establishment of F12 theory in the 2000s. Rapid progress in recent years has significantly extended the application range of explicitly correlated theory, offering the potential of an accurate wave-function treatment of complex systems such as photosystems and semiconductors. This perspective surveys explicitly correlated electronic structure theory, with an emphasis on recent stochastic and deterministic approaches that hold significant promise for applications to large and complex systems including solids.

Promotion of astrocytoma cell invasion by micro RNA-22 targeting of tissue inhibitor of matrix metalloproteinase-2.

OBJECTIVE Diffuse astrocytomas (DAs) have a high recurrence rate due to diffuse infiltration into the brain and spinal cord. Micro RNAs (miRNAs) are small noncoding RNAs that regulate gene expression by binding to complementary sequences of target messenger RNA (mRNA). It has been reported that miRNA-22 (miR-22) is involved in the invasion of some cancer cell lines. The aim of this study was to identify the biological effects of miR-22 in regard to the invasion of human DAs. METHODS The authors evaluated whether the level of miR-22 is elevated in human spinal DAs by using miRNA chips. Next, the role of miR-22 in 1321N1 human astrocytoma cells was investigated. Finally, to elucidate whether miR-22 promotes invasion by astrocytoma cells in vivo, the authors transplanted miR-22 overexpressed astrocytoma cells into mouse thoracic spinal cord. RESULTS The miR-22 significantly upregulated the invasion capacity of 1321N1 cells. Computational in silico analysis predicted that tissue inhibitor of matrix metalloproteinase-2 (TIMP2) is a target gene of miR-22. This was confirmed by quantitative reverse transcription polymerase chain reaction and Western blotting, which showed that miR-22 inhibited TIMP2 mRNA and protein expression, respectively. Luciferase reporter assays demonstrated that miR-22 directly bound the 3'-untranslated regions of TIMP2. The authors further showed that miR-22 promoted invasiveness in 1321N1 astrocytoma cells when transplanted into mouse spinal cord. CONCLUSIONS These data suggest that miR-22 acts to regulate invasion of 1321N1 astrocytoma cells by targeting TIMP2 expression. Additional studies with more cases and cell lines are required to elucidate the findings of this study for a novel treatment target for spinal DAs.

Significance of the Pars Interarticularis in the Cortical Bone Trajectory Screw Technique: An In Vivo Insertional Torque Study.

STUDY DESIGN: Retrospective study. PURPOSE: Cortical bone trajectory (CBT), a more medial-to-lateral and shorter path than the traditional one for spinal fusion, is thought to be effective for severely degenerated vertebrae because screws are primarily stabilized at the posterior elements. We evaluated the efficacy of this approach through in vivo insertional torque measurement. OVERVIEW OF LITERATURE: There has been only one prior in vivo study on CBT insertional torque. METHODS: Between January 2013 and April 2014, a total of 22 patients underwent posterior lumbar fusion using the CBT technique. The maximum insertional torque, which covers the radial strength needed for insertion, was measured for 113 screws, 8 of which were inserted for L5 spondylolysis. The insertional torque for cases with (n=8) and without (n=31) spondylolysis of L5 were compared using one-way analysis of variance (ANOVA). To evaluate vertebral degeneration, we classified 53 vertebrae without spondylolysis by lumbar radiography using semiquantitative methods; the insertional torque for the 105 screws used was compared on the basis of this classification. Additionally, differences in insertional torque among cases grouped by age, sex, and lumbar level were evaluated for these 105 screws using ANOVA and the Tukey test. RESULTS: The mean insertional torque was significantly lower for patients with spondylolysis than for those without spondylolysis (4.25 vs. 8.24 in-lb). There were no statistical differences in insertional torque according to vertebral grading or level. The only significant difference in insertional torque between age and sex groups was in men <75 years and women ≥75 years (10 vs. 5.5 in-lb). CONCLUSIONS: Although CBT should be used with great caution in patient with lysis who are ≥75 years, it is well suited for dealing with severely degenerated vertebrae because the pars interarticularis plays a very important role in the implementation of this technique.

Explicitly correlated frequency-independent second-order green's function for accurate ionization energies.

Explicitly correlated second-order Green's function (GF2-F12) is presented and applied to polycyclic aromatic hydrocarbons (PAHs), oligothiophene, and porphyrins. GF2 suffers from slow convergence of orbital expansions as in the ordinary post Hartree-Fock methods in ab initio theory, albeit the method is capable of providing quantitatively accurate ionization energies (IE) near the complete basis set limit. This feature is significantly mitigated by introducing F12 terms of explicitly correlated electronic structure theory. It is demonstrated that GF2-F12 presents accurate IE with augmented triple-zeta quality of basis sets. The errors from experimental results are typically less than 0.15 eV for PAHs. © 2016 Wiley Periodicals, Inc.

A case of T2 radiculopathy after anterior C5-6 fusion.

Thoracic radiculopathy is a rare entity. Symptomatic adjacent-segment disease after anterior cervical fusion occurs commonly in the lower cervical spine segment. We describe the clinical presentation and treatment of T2 radiculopathy after C5-6 anterior fusion. A 60-year-old man presented with the right axillary pain for 3 months. He had undergone C5-6 anterior fusion for cervical spondylosis 5 years prior. Computed tomography (CT) and magnetic resonance images showed T2-3 degenerative disease. C5-6 anterior fusion exacerbated the T2-3 segment involved in the patient's scoliotic deformity. After 2 months of conservative treatment, we decompressed the T2 foramen via T2-3 hemilaminectomy and partial facet resection. After the surgery, his symptoms disappeared. T2 radiculopathy is rare but should be considered in the differential diagnosis of chest pain. Surgeons should pay attention not only to adjacent-segment disease but also to segmental degeneration at the apex of a scoliotic deformity after cervical anterior fusion.

A Pilot Clinical Study of Olfactory Mucosa Autograft for Chronic Complete Spinal Cord Injury.

Recent studies of spinal cord axon regeneration have reported good long-term results using various types of tissue scaffolds. Olfactory tissue allows autologous transplantation and can easily be obtained by a simple biopsy that is performed through the external nares. We performed a clinical pilot study of olfactory mucosa autograft (OMA) for chronic complete spinal cord injury in eight patients according to the procedure outlined by Lima et al. Our results showed no serious adverse events and improvement in both the American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade and ASIA motor score in five patients. The preoperative post-rehabilitation ASIA motor score improved from 50 in all cases to 52 in case 2, 60 in case 4, 52 in case 6, 55 in case 7, and 58 in case 8 at 96 weeks after OMA. The AIS improved from A to C in four cases and from B to C in one case. Motor evoked potentials (MEPs) were also seen in one patient, reflecting conductivity in the central nervous system, including the corticospinal tract. The MEPs induced with transcranial magnetic stimulation allow objective assessment of the integrity of the motor circuitry comprising both the corticospinal tract and the peripheral motor nerves.We show the feasibility of OMA for chronic complete spinal cord injury.

Radiological Evaluation of the Initial Fixation between Cortical Bone Trajectory and Conventional Pedicle Screw Technique for Lumbar Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective study. PURPOSE: To compare initial fixation using the cortical bone trajectory (CBT) technique versus conventional pedicle screws (PS) in radiographs of postsurgical lumbar degenerative spondylolisthesis. OVERVIEW OF LITERATURE: Few reports have documented the holding strength of CBT technique for spondylolisthesis cases. METHODS: From October 2009 to June 2014, 21 cases of degenerative spondylolisthesis were surgically treated in our institution. Ten were treated with conventional PS technique and 11 of with CBT technique. Mean lumbar lordosis and percent slippage were evaluated preoperatively, immediately after surgery, and 6 months and 1 year postoperatively using radiographs. We also investigated percent loss of slip reduction. RESULTS: There were statistically significant differences between preoperative percent slippage and postoperative slippage in both PS and CBT procedures over 1 year, and both techniques showed good slip reduction. On the other hand, lumbar lordosis did not change significantly in either the PS or CBT groups over 1 year. CONCLUSIONS: CBT technique showed similarly good initial fixation compared with the PS procedure in the treatment of lumbar degenerative spondylolisthesis.

Motor evoked potential and voluntary EMG activity after olfactory mucosal autograft transplantation in a case of chronic, complete spinal cord injury: case report.

The efficacy of olfactory mucosal autografts (OMAs) for chronic spinal cord injury (SCI) has been reported, but there is no report documenting electrophysiological conductivity via the emergence of motor evoked potentials (MEPs). We report the case of a 39-year-old man with chronic, complete SCI at T8, who exhibited MEPs after OMA transplantation, and, with intensive rehabilitation, was ultimately able to ambulate with short leg braces and Lofstrand crutches. The initial injury occurred in a motor vehicle accident in November 1999 and resulted in a complete loss of sensorimotor function below T8. OMA transplantation to the injury site was performed in March 2010 in combination with intensive pre- and postoperative rehabilitation. The patient exhibited voluntary electromyograph (EMG) activity and MEPs at 96 and 144 weeks after transplantation and he was was ambulatory with short leg braces and Lofstrand crutches at 144 weeks after transplantation. We were able to elicit MEPs after OMA with intensive rehabilitation. To our knowledge, this is the first report of recovery of electrophysiological conductivity in the spinal cord after any type of treatment for chronic, complete SCI.

"Do Not Follow the Tail": A Practical Approach to Remove a Sheared Lumbar Catheter Fragment Avoiding Its Migration into the Spinal Canal.

BACKGROUND: Catheter shearing is one of the most common complications of various neurosurgical modalities that use an intrathecal lumbar catheter. The sheared catheter fragment often can spontaneously migrate into the spinal canal; however, in some cases, the end of the fragment will remain outside the spinal canal. In this situation, the consulting neurosurgeons may try to retrieve the catheter fragment by approaching it directly through the catheter tract. This simple maneuver, however, can cause the fragment to slip into the spinal canal before it is secured, as we experienced recently in 2 cases. Because the fragment of the sheared catheter slipped while manipulating it within the catheter tract, we suggest that surgeons not approach the fragment along the tract to prevent it from migrating downward. METHODS: Using the operative findings of an illustrative case, we describe how to avoid downward migration of the catheter fragment when retrieving a sheared lumbar catheter. RESULTS: We found that the sheared catheter of a lumbar-peritoneal shunt was slowly slipping along with the pulsatile movement of cerebrospinal fluid within the catheter tract. We successfully retrieved the fragment by approaching it from outside the catheter tract. CONCLUSIONS: We propose that surgeons approach the fragment from outside of the catheter tract. One should keep in mind a simple phrase, 'Do not follow the tail', when retrieving the sheared lumbar catheter fragment.

Extramedullary Conus Ependymoma Involving a Lumbar Nerve Root with Filum Terminale Attachment.

PURPOSE: In the current report, we describe a case of an extramedullary ependymoma involving a lumbar nerve root near conus medullaris. Spinal ependymomas commonly present as intramedullary tumors in the cervical or thoracic cord or as tumors arising from the conus medullaris or the filum terminale. In this case, we showed an extramedullary conus ependymoma involving a lumbar nerve root with filum terminale attachment. CASE PRESENTATION: A 69-year-old woman presented with lower back pain, but without sensory disturbance or motor weakness in her lower extremities. CLINICAL ASSESSMENT: Magnetic resonance imaging revealed an intradural mass at T12-L1 at the conus medullaris, which was totally resected. Histopathology revealed a non-myxopapillary ependymoma (WHO grade 2). Postoperatively, the patient did well and displayed no neurological deficits. Moreover, no radiotherapy was required. CONCLUSIONS: This report documented a rare case of intradural extramedullary ependymoma located at the conus medullaris, involving the lumbar nerve root, and attached to the filum terminale. Although extramedullary ependymomas at this region are more frequently classified as myxopapillary, histopathological examination revealed this tumor as a non-myxopapillary ependymoma.

Clear Zone Formation around Screws in the Early Postoperative Stages after Posterior Lumbar Fusion Using the Cortical Bone Trajectory Technique.

STUDY DESIGN: Retrospective study. PURPOSE: To evaluate the initial fixation using the cortical bone trajectory (CBT) technique for posterior lumbar fusion through assessment of the clear zones around the screws and the risk factors involved. OVERVIEW OF LITERATURE: Postoperative radiolucent zones (clear zones) are an indicator of poor conventional pedicle screw fixation. METHODS: Between January 2013 and April 2014, 19 patients (8 men and 11 women) underwent posterior lumbar interbody fusion or posterior lumbar fusion using the CBT technique. A total of 109 screws were used for evaluation with measurement of the maximum insertional torque of last two screw rotations. Clear zone-positivity on plain radiographs was investigated 6 months after surgery. The relation between intraoperative insertional torque and clear zone-positivity was investigated by one-way analysis of variance. In addition, the correlation between clear zone-positivity and gender, age (<75 years old or >75 years old), or operative stabilization level (<2 or >3 vertebral levels) was evaluated using the chi-square test. RESULTS: Clear zones were observed around six screws (5.50%) in five patients (26.3%). The mean insertional torque (4.00±2.09 inlbs) of clear zone-positive screws was lower than that of clear zone-negative screws (8.12±0.50 in-lbs), but the difference was not significant. There was a significant correlation between clear zone-positivity and operative level of stabilization. CONCLUSIONS: The low incidence of clear zone-positive screws indicates good initial fixation using the CBT technique. Multilevel fusions may be risk factors for clear zone generation.

Isthmus-guided Cortical Bone Trajectory Reduces Postoperative Increases in Serum Creatinine Phosphokinase Concentrations.

OBJECTIVE: This study aimed to determine whether an isthmus-guided cortical bone trajectory (CBT) technique provides better clinical outcomes than the original cortical bone trajectory CBT technique for screw fixation. METHODS: A consecutive series of 21 patients with lumbar spondylolisthesis who had undergone CBT screw fixation using the original technique from June 2012 to February 2013 and 33 who had undergone the isthmus-guided technique from March 2013 to August 2014 was retrospectively reviewed. The number of screws inserted, interbody fusion and screw misplacements, amount of blood loss, and creatinine phosphokinase (CPK) ratios (postoperative day 1 CPK/preoperative CPK) were reviewed to evaluate clinical outcomes and compared between the original and isthmus-guided CBT techniques. RESULTS: Postoperative serum CPK concentrations were significantly lower with the isthmus-guided than the original CBT technique (P < 0.05). There were no significant differences in age, blood loss, or number of screws, vertebral interbody fusions and patients with history of previous decompression surgery at the same level. There was a trend to higher incidence of screw misplacement with the original than the isthmus-guided CBT technique; this difference was not significant (P = 0.53). There were no major intraoperative complications. In all the CBT procedures performed in our institution, almost half (47%) the screw misplacements have occurred at the level of L5 , and most on the right side. CONCLUSIONS: Right-handed operators should take care inserting screws on the right side. From the viewpoint of screw misplacement, isthmus-guided CBT provides superior or equivalent safety to the original CBT technique.