Lateral mass screw fixation is now the surgical procedure of choice for stabilizing the cervical spine in the treatment of patients with cervical instability. Several techniques have been proposed for safe rigid fixation. We describe a simple and reliable method for lateral mass screw fixation using an original device of our own design. Using this device under fluoroscopic assistance, the lateral mass screw is directed at an angle 25 degrees laterally and dorsally just until it meets the posterior ridge of the transverse process of the cervical spine. Over the past seven years between 2002 and 2008, lateral mass screw fixation was performed in a total of 26 patients with cervical instability in our situation. Our unique method was applied to 15 of those 26 patients, including 11 men and 4 women ranging in age from 37 to 84 years old. Retrospective analysis demonstrated that there were no surgical complications, such as screw malposition resulting in vascular or neural damage. We discuss our surgical method for lateral mass screw fixation, concentrating on the avoidance and management of complication.

  Objective : When deciding on a strategy for posterior fixation in atlantoaxial instability, it is very important to ascertain preoperatively about the location of the vertebral artery and the shape of C1 and C2. Herein, we report 5 cases in which we successfull operated according to a plan devised using three-dimensional (3D) models.

  Methods : In this study, full-scale 3D models were custom-made on the basis of multi-planer reconstruction from preoperative 3D computed tomography (CT) from the occiput to the middle cervical spine for 5 patients (3 men and 2 women) with atlantoaxial instability (age range, 32-75). We planned each surgical strategy by actually applying instruments to these 3D models before surgery.

  Results : In one of the 2 earliest cases, we performed a bilateral posterior atlantoaxial transarticular screw fixation, as developed by Magerl. In the other case, utilizing a posterior atlantoaxial transarticular screw with a connection to the atlas claw on one side, a C2 pedicle screw with a connection to the atlas claw was completed on the opposite side. In the third case, we fixed a bilateral C1 lateral mass screw to a C2 pedicle screw. In yet another case, we fixed the bilateral C1 lateral mass screws to a C2 pedicle screw on one side and a C2 laminar screw on the opposite side. In the final case, involving posterior and lateral ponticles on the C1 posterior arch, bilateral C2 pedicle screws were connected to a C1 lateral mass screw on one side and a C1 atlas claw on the opposite side were achieved. In all cases, stabilization according to preoperative plans was accomplished, and postoperative courses were good.

  Conclusions : A navigation system is a useful support tool for accurately applying instruments to the spine, but the preoperative trial installation of instruments such as screw assemblies using 3D models is also a great help and offers reassurance for the surgeons.

  Various procedures have been recommended for the surgical treatment of cubital tunnel syndrome. They are basically divided into ulnar neurolysis and anterior transposition with or without epicondylectomy.

  We report 51 operations to treat cubital tunnel syndrome among the 636 operations of the peripheral nerve during three years between 2005 and 2007. We analyzed our procedures in relation to the more detailed anatomical differences in the nature and location of the entrapment.

  There were five areas which had caused ulnar nerve entrapment at the elbow. From the distal side, they were ① the flexor carpi ulnaris muscle, ② cubital tunnel, ③ epicondyle, ④ intermuscular septum, and ⑤ arcade of Struthers. In addition, there were other areas ⑥ where the ulnar nerve entrapment was caused by unusual structures, such as ganglion and others.

  Our surgical cases were classified based upon the location ( ① to ⑤ ) and the nature of the pathology ⑥ of the entrapment as follow : ① 40 cases, ② 38 cases, ③ 8 cases, ④ 1 cases, ⑤ 1 cases, and ⑥ 7 cases. Cases of ① and ② made up the majority.

  The neurolysis was performed in 8 cases and anterior transposition either submuscular or epicondylectomy was added in the rest. There was no difference in the postoperative course between these two groups.

  Either neurolysis or anterior transposition were performed at ①, ② and ⑥. Anterior transposition was performed in all of the cases of ③, ④, ⑤ and epicondylectomy was added to the 28 cases where the ulnar nerve dislocated to anteriorly of the epicondyle by flexion of the elbow. Postoperative results were excellent in all of the cases.

  Although the location of entrapment can be presumed by the presence of Tinel-like sign and nerve conduction velocity study, we found that intraoperative findings were most important. We need to be aware of the anatomical differences in entrapment location, and it is important to choose the operative method suitable for each different scenario.

  The purpose of this study is to elucidate the characteristics of C3-4 level cervical spondylotic myelopathy. This study included 11 patients, 9 men and 2 women. Mean age at admission was 75.4 years. Clinically, all of the patients had clumsy hands and gait disturbance. There was also wooziness in 7 cases. This unusual symptom may contribute to late diagnosis. Radiologically, hypermobility at the C3-4 segment compensating for decreased mobility at lower segments may induce hypertrophy of the ligamentum flavum and disc bulging. This may be related to the occurrence of C3-4 level myelopathy.

  Background : Minimally invasive surgery has become more and more important for the treatment of traumatic spine fractures. A procedure involving percutaneous insertion of cannulated pedicle screws has recently been developed as a minimally invasive alternative to the open technique during instrumented fusion procedures.

  Purpose : We report on the technique and pitfalls of percutaneous pedicle screw insertion and compare this percutaneous approach versus an open approach for dorsal instrumentation with pedicle screws to the spine.

  Methods : Thirty one patients (percutaneous) and 36 patients (open) underwent bilateral pedicle screw fixation at the thoracolumbar one level. One hundred forty-four pedicle screws were bilaterally inserted into the pedicles and connected with rods using either an open dorsal standard or a percutaneous approach. Operation time, loss of blood, recovery rate of JOA, VAS (day 1), VAS (day 7), hospital stay, laboratory findings (CPK and CRP) were all evaluated to objectify possible advantages for the percutaneous operation technique.

  Results : Operation time, loss of blood, VAS (day 1), VAS (day 7), hospital stay, and laboratory findings (CPK and CRP) were significantly lower in the percutaneous group.

  Conclusions : Based on the results we found in the present study, percutaneous screw insertion can bring moderate advantages in acute phase although this maneuver requires scrupulous care with a small surgical field.

  The purpose of this study was to evaluate the effect of age on outcome of anterior spinal surgery in elderly patients with cervical spondylosis.

  We reviewed the cases of 14 non-elderly (<65 years of age), 9 early elderly (65-74 years of age), and 11 late elderly (>75 years of age) patients in whom anterior cervical decompression and fusion were performed for cervical spondylosis myelopathy. Effect of age on surgical outcome was statistically analyzed by evaluating the JOA score, Barthel index, and their recovery rates.

  Preoperative JOA scores and Barthel index declined with age. Postoperatively, JOA scores and Barthel index rose in all three age groups but only the increase in JOA score in the non-elderly group was statistically significant. Recovery rates of JOA scores were poor in both the early and late elderly patient groups.

  Although an age effect on outcome for anterior spinal surgery in elderly patients is evident, there is still the possibility of neurological recovery and improvement in activity of daily life in elderly patients. We need a special management to avoid postoperative confusion in late elderly patients.

  Objective : To analyze the significance of postoperative serum creatine phosphokinase (CPK) elevation as an indicators of muscle damage after various lumbar surgeries and to find a correlation between postoperative CPK elevation and various factors.

  Clinical Materials and Methods : Serum concentrations of CPK were measured serially in 133 patients who underwent one level lumbar surgery : unilateral foraminotomy (UF ; 6 cases), bilateral partial laminectomy (BP ; 11 cases), unilateral partial laminectomy with bilateral ligamentectomy (UPBILIT ; 16 cases), discectomy (DS ; 45 cases), pedicle screw removal (PSR ; 19 cases) and transforaminal lumbar interbody fusion with pedicle screws (TLIF ; 25 cases). In addition to these cases, eleven cases of facet thermocoagulation (Thermo) were also studied. From these cases, peripheral venous blood samples were collected serially before and one day after surgery. The serum concentration of total CPK was measured. The serial postoperative change in CPK level was then evaluated with respect to age, gender, type of surgery, blood loss during surgery and surgery time.

  Results : CPK changes in BP 14.4 SD 60%, in UF 26.7 SD 47%, in UPBILIT 28.9 SD 87%, in DS is 34.7 SD 106%, in Thermo 52.3 SD 30%, in PSR 249.8 SD 182%, in TLIF 464.3 SD 493% (SD : standard deviation). CPK elevation in TLIF was significantly higher than that in the other surgery (p<0.002), There were statistical significant correlations to blood loss (r=0.43, r²=0.18, p<0.0002) and surgery time (r=0.38, r²=0.15, p=0.0002), however, no significant correlation to age and gender. And finally, there were no cases with postoperative deterioration of low back pain.

  Conclusion : Although the clinical significance of the CPK elevation after surgery is still not clear, serum CPK elevation reflects to muscle trauma.

  Intraoperative motor-evoked potential (MEP) monitorings were performed during 100 spinal operations. Among these 100 operations, transcranial MEP (TCMEP) were performed in 98 operations including 30 cervical laminoplasties, 22 lumbar laminectomies, 12 cervical anterior fusions, 9 lumbar discectomies, 7 posterior interbody fusions, 7 vertebroplasties, 6 lumbar spinal canal fenestrations, and 4 spinal tumors. Transcranial stimulations at 300～400 V were used and applied by screw electrodes placed in the scalp and the resultant electromyographic responses were recorded with surface electrodes on the affected muscles. To exclude the effects of muscle relaxants on TCMEP, compound muscle action potential (CMAP) by supra-maximum stimulation of the peripheral nerve immediately after transcranial stimulation was recorded in 97 operations. Among 80 patients who had had no preoperative and postoperative definitive motor palsy, the amplitudes of TCMEP compensated by CMAP after peripheral stimulation decreased less than 20% in 4 patients with cervical spondylosis, thus the false positive rate was 4.9%. A false negative finding was not recognized in one patient who had had postoperative newly progressed motor palsy. The improvement of mild motor disturbance such as reduction of grasping force or intermittent claudication could not be monitored intraoperatively by conventional TCMEP. Among 16 patients who had had preoperative severe motor palsy, TCMEP could not be recorded preoperatively in 20 limbs of 12 patients. After the decompression of the spinal cord in these 12 patients, TCMEP could be recorded in 3 limbs in 3 patients, but postoperative improvement of the motor function was recognized in only one patient. In conclusion, although TCMEP monitoring during spinal surgery might seem to be too sensitive, it should be performed to prevent most postoperative severe adverse motor function events after spinal surgery that is intended as functional surgery. Finally, the selection of the muscles for recording should be elaborately decided for the most effective TCMEP monitoring during spinal surgery.

  Introduction : The disease specific outcome scale for cervical spondylotic myelopathy (CSM), such as JOA (Japanese Orthopedic Association) score or NCSS (Neurosurgical Cervical Spine Scale) evaluates only the patient's objective neurological status or symptoms. Whereas, a generic outcome scale represented by SF-36, can assess a patient's subjective physical and mental conditions. We prospectively evaluated the health-related quality of life (QOL) of patient with CSM pre-and postoperatively using SF-36v2 and visual analogue scale (VAS) in addition to JOA score and analyzed correlations among them.

  Methods : Twenty three patients with CMS treated surgically in our institute were enrolled in this study. Fourteen were male and nine were female and average age was 63.6 years old. Seven patients underwent anterior decompression and fusion and 16 underwent laminoplasty. The patients were evaluated using JOA score, VAS and SF-36 preoperatively and 6 months after operation.

  Results : JOA score significantly improved from 11.1±3.2 to 14.3±2.3 postoperatively. VAS was reduced from 3.3±3.6 to 1.8±2.2. The CSM patients demonstrated a lower score in all SF-36 subscales. Physical functioning, role functioning-physical, role functioning-mental, and mental health improved significantly at 6 months after operation. JOA score and VAS significantly correlated with physical functioning and bodily pain, respectively.

  Conclusion : Deterioration of not only physical function but also mental function was proven in patients with CSM, and both aspects significantly improved after surgery. SF-36 is the useful tool to better understand the QOL of CSM patients and the efficacy of the treatment.

  Facet syndrome is characterized by persistent low back pain and it is ofteh treated with surgical interventions such as cutting the nerve branches lateral to the facet joints, percutaneous radiofrequency (RF) facet denervation, and kryorhizotomy. The target of these surgical techniques is the transverse process bases where the medial nerve branches innervate the facet. However, highly variable success rates have been demonstrated with beneficial outcomes in different series. In this study, we carried out laser denervation to the dorsal surface of the facet capsule, an area that is richly innervated with medial nerve branches. Irradiation was performed on superior, middle, and inferior portions. One year after laser denervation, the average pain reduction of all cases was 76.2%, while that of the 68 cases treated without lumbar surgery was 79.9% and that of the 7 cases with lumbar surgery was 45.6%. The dorsal surface of the facet capsule might be a more preferable target for facet denervation. A history of prior spinal surgery has a marked adverse impact on outcomes. Outcomes are much more difficult to predict in patients with such a history. Based on the lumbar level, the outcome of L5/S cases was not good compared to other levels. Nerve distribution in the L5/S facet is different from other levels and the facet is broad compared to other levels as well. Such factors might affect an adverse impact on outcomes.

  Anterior cervical fusion surgery can cause fusion complications such as range of motion (ROM) restriction and degenerative changes of adjacent vertebral bodies. Disc removal is avoided if possible in young patients baring healthy disc and maintaining ROM. We adopted a modification of the transvertebral anterior micro-decompression (TVAD) technique for local cord compression or foraminal stenosis. The decompression is achieved by drilling a keyhole in the upper vertebral body, and most of the disc tissue and bony structure such as vertebral body and Luschka joint are preserved. A recent nineteen patients were prospectively analyzed for this procedure. TVAD was applied for 6 cases of cervical disc hernia, 5 cases of spondylotic radiculopathy, 5 cases of foraminal stenosis, and 3 cases of cervical spondylotic amyotrophy. This procedure was evaluated for neurological assessment, decompression, recurrence, cervical alignment, range of motion (ROM), and disc height. Neurological improvement and the decompression were well achieved in all cases. None of these cases recurred. The cervical alignment and ROM was maintained though the disc height decreased a mean 0.63 mm in 10 cases. TVAD is an effective treatment for local compression including cervical radiculopathy. It avoids unnecessary violation of the disc space and most of the bony stabilizers of the cervical spine, and preserves physiological cervical function. Short-term results of this technique are quite encouraging. Longer-term analysis can helpin outlining the true benefits of this technique.

  We report a 17-year-old male patient with a presyrinx state due to Chiari malformation. Neurological examination revealed weakness of both upper extremities. MRI image revealed a Chiari malformation and hyperintensity on a T2 weighted image at the gray matter of cervical spine. The patient underwent enhanced MRI and angiography, but there were no abnormalities evident on these examinations. We underwent foramen magnum decompression, C1 laminectomy, and duroplasty for the Chiari malformation. The hyperintensity of the spinal cord evidenced on the T2-weighted image was improved a week later. We were able to prevent progression to syringomyelia by properly treatmening the presyrinx state.

  Intramedullary lipomas of the cervical spinal cord without dysraphism are rare lesions, accounting for only 1% of spinal cord tumors. We experienced a 60-year-old male with cervicothoracic (C6 to T2) lipoma who complained of dysesthesia in his lower extremities. Magnetic resonance imaging identified a tumor which was dorsolateral to the cord in the intramedullary legion. In these cases, a fat suppression sequence is useful for diagnosis. He underwent surgery for partial removal of the tumor and expansive laminoplasty. Postoperative course of the patient was uneventful and follow-up showed an improvement in sensory disturbance.

  The authors report a rare case of an anterior sacral meningocele (ASM) associated with an epidermoid cyst, manifesting as an increasingly enlarged subcutaneous mass in the gluteal region. A 66-year-old male presented with a pygal mass lesion. Plain radiographs and three-dimensional computed tomography (CT) demonstrated a scimitar defect of the sacrum. Magnetic resonance images (MRI) revealed two cystic mass components in the presacral and subcutaneous region, which appeared to be continuous with the dural sac. Subsequent to sacral laminectomy, an exploration of the ostium was performed. However, during surgery, we could not find the communication between the thecal sac and the cysts. Reconstruction of the dural sac and suture ligation of both cysts were performed after resection of the cyst wall. The histological diagnosis was neutrophil epidermoid cyst, based on the finding in which the cyst wall consisted of squamous epithelia with infiltration. The patient remained neurologically intact postoperatively and had no further gluteal mass lesions. Follow-up MR images obtained 9 months after surgery showed a gradual reduction in size of both cystic components.

  Anterior spinal artery aneurysms are rare, and usually associated with vascular pathology such as arteriovenous malformations, Moyamoya disease or coarctation of the aorta. We report a case of subarachnoid hemorrhage due to rupture of an aneurysm without concomitant vascular disease. A 71-year-old man suddenly presented with severe headache, and was admitted to our hospital. Computed tomography revealed subarachnoid hemorrhage. Angiography demonstrated bilateral vertebral artery occlusion, and dilated anterior spinal artery which perfused the posterior circulation. The aneurysm was located at C3 level of the anterior spinal artery. Corpectomy of C2 and C3, and clipping of the aneurysm was performed the next day. We discuss the etiology and treatment of anterior spinal artery aneurysms.

  We report a rare case of cervicothoracic neurenteric cyst. A 53-year-old man presented with right shoulder pain and finger dysesthesia. Magnetic resonance imaging (MRI) showed a ventrolaterally situated mass strongly compressing the cervicothoracic spinal cord. The cyst fluid appeared hypointense on the T1-weighted images and hyperintense on the T2-weighted images. Whole spinal MRI showed no other abnormalities. An hemilaminectomy of C7 and T1 was performed. A yellowish cyst existed ventrolateral to the spinal cord from which mucinous cyst fluid was aspirated. The cyst wall adhered tightly to the ventral spinal cord. Total excision was achieved through meticulously sharp dissection. The patient's symptoms disappeared after the surgery. Pathological findings were compatible with those of a neurenteric cyst. We discuss the general features of spinal neurenteric cysts and the necessity of surgical excision.

  A good hemostastatic environment is indispensable in the spinal surgery even when administering a strict anticoagulant therapy. The restoration of coagulant function can be achieved by the discontinuation of the anticoagulant agents and the reversal of anticoagulant status by administering vitamin K and/or some coagulant factors. However, sudden restoration of the coagulation function may cause a thromboembolic event for those patients who need anticoagulant therapy. The perioperative management of such patients is therefore much more complicated.

  A 59-year-old man receiving warfarin as an anticoagulant medication because he suffered from infectious endocarditis, and had had a mitral and aortic valve replacement operation two years ago. A year later, he suffered a cerebral infarction despite his warfarin medication. This time, he had a cervical spinal epidural hematoma beginning with neck pain and left hemiparesis that developed into tetraparesis. The spinal surgery for hematoma removal and laminoplasty was done under anticoaguation reversal. A drainage tube was placed into the epidural space. The anticoagulation with continuous administration of heparin was started 12 hours postoperatively for functional maintenance of his mechanical cardiac valve. His tetraparesis was improving. The drainage tube was removed 48 hours postoperatively. However, spinal rebleeding was encountered three hours after the drain removal, and the patient developed tetraparesis again. An emergency operation was performed. An epidural drain was placed again, and it was removed 12 hours later when the drainage was completed and coagulation function was maintained. The heparinization was restarted six hours after drain removal. Rebleeding did not occur, and the anticoagulant therapy was transferred from heparin injection to warfarin medication. The rehabilitation of motor function was gradually progressed.

  Herein, we consider the safest, optimal perioperative management of spinal surgery for the patients taking anticoagulation therapy such as warfarin medication.

  A 37-year-old female presented with the upper cervical astrocytoma manifesting as a 1-year history of the right motor weakness and hypesthesia of the upper and lower extremities, and as a 2-month history of the progressive respiratory and swallowing disturbance and paraparesis. Cervico-medullary magnetic resonance (MR) imaging demonstrated an intramedullary mass at the C1-2 levels with enhancement after gadolinium injection and a syrinx which spread from the medulla oblongata to the upper thoracic spinal cord. Cervical laminoplasty at the C1-4 levels was performed and the tumor was subtotally removed. The surgical manipulation of the tumor at the attachement site was changed according to the state of the motor evoked potential (MEP). Histological examination showed a diffuse astrocytoma. She recovered from her symptoms postoperatively. It was thought that we could improve intramedullary tumor resection and reduce postoperative motor deficit by using intraoperative MEP.

  We report a case of lumbar intradural lipoma producing motor weakness and dysesthesia of the bilateral lower extremities and bladder dysfunction. A 57-year-old man, who suffered from motor weakness and dysesthesia of the bilateral lower extremities since ten years ago, suddenly started gaining weight periodically. His bladder function deteriorated as his weight gain continued. He visited our outpatient service after a magnetic resonance (MR) study at a nearby hospital revealed an unusual mass lesion occupying his lumbar spinal canal from L1 to L3/4, which seemed to be an intradural lipoma. Approached by right L1-3 recapping hemilaminoplasty, the tumor was partially removed until a sufficient volume reduction was confirmed. The patient's symptoms were slightly improved, and he was discharged one week after the operation without any complication. The mechanism of evolving symptoms in the involved patients seems to have some relation to gaining weight. Partial resection seemed to be the ideal treatment strategy for lumbar intradural lipoma.

  Neurinomas of the first two cervical nerve roots represent approximately 5% of all spinal neurinomas and 18% of the cervical localizations. However, from the aspect of the anatomy of the vertebral artery and neighboring venous structures, it is more useful to classify these tumors as C1-3 level tumors and others, so that, C1-3 neurinomas account for 17.7% of all cervical tumors, and for 57.7% at the extradural region, in 30% of all dumbbell type. Moreover, we can remove tumors at this level totally without injuring the motor function of the nerve roots.

  In the C1-2 level tumors, because of the defect of the intervertebral foramen, the tumor is apt to grow larger than ones at another level, but conversely, we can operate favorably in a wider field. In C2-3 tumors, it is important to deal with the tumor in the intravertebral foramen in a severely narrow space.

  Three cases are presented. Case 1, a 57-year-old man, presented with an extradural tumor at the C1-2 level, Case 2, a 37-year-old man, had a C2-3 tumor, intra-extradural and intra-extracanal dumbbell tumor, and Case 3, a 25-year-old woman, had a C2-3 intradural intra-extracanal dumbbell tumor, which was confirmed to be in the epiarachnoidal space. Tumors in all 3 cases were removed almost totally without using instruments ; that is, less invasively.

  We pointed out 4 surgical technical factors, first, the anatomical difference between C1-2 and C2-3 level, that is, whether the intervertebral foramen exists or not, second, the control method of the bleeding from the venous plexus' neighboring vertebral artery, third, how to remove the extracanal component of the tumor, paying attention to the vertebral artery, without instrumentation, fourth, how to close the dura without using other tissues.

  Objective : Once atlantoaxial joint instability has been detected, the goal of surgery is to reduce pathological subluxation, decompress neural elements and maintain vertebral column alignment. Herain, the surgical technique for internal fixation and fusion at the atlantoaxial joint is presented with an emphasis on complication avoidance.

  Patients and methods : The patient record included a total of 12 patients with the atlantoaxial instability (11 male and 1 female), who underwent surgery over the past four years. The age of the patients ranged from 16 to 75 years old. Patients were classified into 7 in trauma group, and 5 in rheumatoid arthritis or degeneration group based on their etiology. Goel-Harms method with a cancellous screw and rod system was preferably used. In the cases of retroodontoid pseudotumor with chronic atlantoaxial instability, the posterior C1 arch was resected and combined with posterior fusion.

  Results and conclusion : None of the patients demonstrated neurological deterioration after surgery. All of the patients with retroodontoid pseudotumor demonstrated neurological recovery with gradually diminishing pseudotumor. In one case treated by Megerl method, revision surgery was accomplished to achieve complete bone fusion. To avoid the surgical complications, selection and safe placement of C2 anchor screws, sufficient exposure of the lateral atlantoaxial joint, and fusion technique are key elements for successful surgery.