The purpose of this study is to describe surgical techniques and clinical outcomes of Minimally Invasive Spine Stabilization(MISt)with vertebral osteotomy for osteoporotic vertebral collapse. These techniques were performed on two patients：Case 1：An 80 year old female, with a L1 osteoporotic vertebral pseudoarthrosis and Case 2：An 80 year old male, with a L2 osteoporotic vertebral collapse with a L2 bone defect. For Case 1, L1 vertebral shortening using pedicle subtraction osteotomy technique and Th11-L3 posterior fusion using percutaneus pedicle screws were performed. In Case 2, L2 vertebral osteotomy with L2/3 modified PLIF using cortical bone trajectory was performed. Significant clinical improvement was obtained in both patients.

It is hard to support an osteoporotic spine only by posterior instrumentation. Vertebral osteotomy techniques enable us to correct a kyphotic spinal column and to get a neural decompression. The advantage of vertebral osteotomy is also to gain a stable anterior support. Therefore, MISt with vertebral osteotomy is a useful and important surgical technique for elderly patients with osteoporotic vertebral collapse.

Purpose：The purpose of this study was to investigate the clinical outcome of spinal fusion for the dialysis associated spondylitis of the lumbar spine.

Materials and Methods：We studied a consecutive series of 146 hemodialysis patients (84 males and 62 females)who underwent lumbar instrumentation surgery, from 2000 until 2011. Operation method, fusion level, perioperative complications, Japanese Orthopaedic Association (JOA) score, revision surgery, and adjacent segment disease were investigated.

Results：One hundred and thirty six cases were treated by posterior lumbar interbody fusion surgery. Thirty eight cases were treated by posterior lumbar fusion surgery. The fusion level was 1 in 94 cases, 2 in 44 cases, 3 in 27 cases, over 4 levels in 9 cases. Perioperative complications were infection (7 cases), hematoma (1 case), want of rigidity(4 cases)back out of cage (4 cases). JOA score was improved from 14.6 to 23.2 postoperatively. The adjacent segment disease occurred in 26 cases, and 34 operations were performed. Revision surgery was performed in 27％ of cases.

Conclusion：Clinical outcome of spinal fusion for the dialysis associated spondylitis of lumbar spine was relatively good, but many cases needed revision surgery because of perioperative complications and adjacent segment disease.

Introduction：PLIF for destructive spondyloarthropathy (DSA) has several problems, such as instrumentation failure, gradually progressing kyphosis deformity and poor post operative clinical outcomes. The purpose of this study is to evaluate the efficiency of Dynamization-PLIF for DSA.

Material and Methods：Ten patients who underwent Dynamization-PLIF in our institution were followed up over two years and were included in this study. Radiographic findings and clinical outcomes (ZCQ, VAS) were measured.

Results and Discussion：An average 3.7mm of shortening in fusion segments were observed within 6 months postoperatively. There was no loosening of pedicle screws. The fusion level and lumbar lordosis kept good alignment. The fusion rate was 100%. Only one case required reoperation for adjacent level impairment. In clinical outcomes, ZCQ and VAS have improved significantly. These results suggested that Dynamization-PLIF is effective for DSA.

Hemodialysis is initiated in approximately 40,000 patients annually in Japan. As this is a costly treatment, this has important financial implications for the Japanese healthcare system.

Antero-lateral partial vertebrectomy (ALPV) using beta-tricalcium phosphate (β-TCP), which is less invasive and removes the need for fusion technique, has been used for decompression in patients with multilevel anterior compression of the cervical cord. Six patients, four men and two women aged 52-80 years (mean 66 years), with hemodialysis lasting 2-40 years (mean 20.7 years) and progressively deteriorating cervical myelopathy were treated by ALPVs using β-TCP at 2-4 consecutive levels (mean 3) between C2-C3 and C6-C7. The neurosurgical cervical spine scale (NCSS) was used for comparison of the neurological status at the initial and follow-up examinations. Computed tomography (CT) was used to monitor the degree of ossification of b-TCPs implanted into the sites of the ALPVs and changes in configuration of the vertebral body. Improvement in NCSS score was 56％ (mean) in four patients at the latest follow up, excluding one patient suffering from cerebral infarction. One patient died due to cardiac failure three months after the ALPVs. Spondylolisthesis affecting C4 occurred in two patients without deterioration of the myelopathy. Resection of the pedicle on the opposite side resulted in asymptomatic complete occlusion of the vertebral artery in one patient. Serial CT confirmed that all β-TCPs blocks had been replaced by newly formed bone by six to twelve months after implantation in three patients, resulting in remodeling of the affected vertebrae. Delayed replacement of β-TCP by newly formed bone occurred in two patients compared to those without hemodialysis. ALPV using β-TCP was also successful in the patients with decreased bone matrix due to hemodialysis.

The objective of this study was to analyze the natural course of CSF leakage secondary to anterior decompression and arthrodesis for cervical degenerative diseases.

The 33 CSF leakage cases reviewed were made up of 30 cases of ossification of the posterior longitudinal ligmament (OPLL) cases and 3 cervical spondylotic myelopathy (CSM) cases. Primarily, repair was performed in all cases, observed with no lumbar subarachnoidal drainage after surgery. Four patients experienced headache, which improved 3 weeks after surgery. No patient needed re-intubation due to airway obstruction(caused by either pseudomeningocele or swelling of the retropharyngeal space after surgery). On MRI, the pseudomenigocele had diminished in 85％ of these cases. Neurological recovery showed no difference between the CSF leakage group and the non CSF leakage group in OPLL cases.

The study demonstrated the need for CSF leakage cases to be kept in hospital for at least 2 weeks in order to observe patients closely, as pseudomeningoceles have been found to regrow particularly between postoperative day 7 and postoperative day 14, and may in turn lead to airway obstruction.

Background：Intraoperative Monitoring(IOM)is often performed during spinal osteotomy for adult spinal deformity. We analyzed a retrospective study involving 109 consecutive patients who underwent posterior thoracolumbar osteotomies from 2010 to 2012. We set a 70％ reduction of amplitude as an alarm point of transcranial electrical stimulation motor evoked potentials (TcMEPs).

Results：Postoperative follow up revealed 16 cases(14.7%)of IOM alerts and 7 cases(6.4％)of new neurological deficits clinically. IOM yielded 7 true positive cases and 5 false positive cases.
Our alarm criteria provided higher sensitivity (100%) and specificity (92%). We experienced 6 cases of TcMEPs recovered by the protective mechanisms of the spinal cord and nerve function without postoperative neurological deteriorations.

Conclusions：IOM is able to predict postoperative neurological deterioration during spinal osteotomy for adult spinal deformity. We recommend the routine use of spinal cord monitoring in the surgery of spinal osteotomy.

Instrumentation failures after lumbosacral fusion sometimes require reconstruction surgeries. It is not enough to merely change rods made of pure titanium with those made of titanium alloy. Therefore we doubled the number of rods(dual rod method)using 5.5-mm titanium alloy rods along with rod connectors to increase the stability. Pedicle screws (PS) were not removed and reused for same-sized rods unless they were broken or significantly loosened. We investigated the clinical results of this method in 12 patients (9 male and 3 female) with the average age at surgery of 71 years. Delayed union was observed at L5/S in 7 patients, T12/L1, L1/2, L2/3, L4/5 and L4/5/S in 1 patient each. Instrumentation failures included rod breakage in 9 patients, PS breakage, PS loosening and infection in 1 patient each. Iliac screws were also used in 9 patients. The average follow-up period was 28 months. Bony fusion was achieved in 11 patients (92%). For the remaining 1 patient, there was no clear zone or instrumentation failure. It is advantageous not to replace any PS system with rods of large diameters with high profile. This method is effective for reconstruction in cases of delayed union and instrumentation failure after lumbosacral fusion.

Blood pressure control with continuous intravenous infusion of nicardipine hydrochloride has been introduced since May 2010, as postoperative hypertension was assumed to be one of the causes of postoperative epidural hematoma (PHE).

Prior to this method of controlling blood pressure, there were six cases (0.57%) of PEH out of 1037 surgeries, and 5 cases (0.48%) required surgical removal of hematoma. Since blood pressure has been strictly controlled postoperatively with nicardipine hydrochloride, there were two cases (0.19%) of PEH out of 1058 surgeries, with none of these requiring removal (p<0.05). This study therefore showed that strict blood pressure control postoperatively with continuous intravenous infusion of nicardipine hydrochloride was effective to reduce the incidence of PEH.

Purpose：To report our management protocol for incidental durotomy.

Materials and Methods：We noted the occurrence of incidental durotomy during surgery in 5 of 101 cases undergoing lumbar spine surgery from January 2010 to March 2013 at our institute. Our management strategies included: 1) Confirming the status of the dural defect；when suctioning cerebrospinal fluid [CSF] cottonoid strips should be used to avoid escape of the cauda equina through the dural defect 2) Using primary sutures (in cases where this is difficult, fascia should be used as patch grafts 3) Ensuring the muscle layers are tightly closed to reduce the dead space 4) Recommending postoperative bed rest for 1 to 3 days.

Result：All 5 cases were successfully treated, and no CSF leakage was observed postoperatively.

Conclusion：Our treatment strategies are useful for the management of dural injury.

Remote cerebellar hemorrhage(RCH)after spinal surgery is very rare, but is still a potentiall life-threatening complication following surgical procedures. We present a case of RCH after lumbar spinal surgery.

[Case]

A 68-year-old woman underwent L2/3/4/5 corrective PLIF due to lumbar spinal stenosis with degenerated listhesis and scoliosis. She acquired a pin-hole dural tear during surgery, without apparent cerebrospinal fluid(CSF)leakage. We repaired the tear with fibrin glue spray. Headache and cerebellar ataxia developed gradually, commencing one day postoperatively. The MRI and CT demonstrated RCH in the cerebellar hemisphere bilaterally.

Conservative treatment in order to control blood pressure and intracranial pressure was undertaken in ICU. The cerebellar hemorrhage and ataxia gradually improved, and she was discharged home 34 days after the onset.

[Discussion and Conclusion]

The proposed mechanism of RCH is that the low CSF pressure, caused by rapid and excessive CSF leakage (due to continuous negative pressure subfascial drainage), induces caudal traction to the cerebellum, which in turn results in the rupture of vessels.

It is important to be aware of CSF leakage as a potential factor in RCH, and subsequently to manage postoperative drainage after CSF leakage with great care.

Introduction：Monitoring of the Bulbocavernosus Reflex (BCR) has been applied to assess the integrity of the low sacral (S2-S4) reflex. However, it is not always reliably implemented. This study evaluates the usefulness of intraoperative BCR monitoring for urinary function in patients with tumors around the conus medullaris and cauda equina. Materials and Methods：We monitored the intraoperative BCR in ten patients with spinal tumors. Four of them showed tethered cord syndrome (TCS). Results：The BCR was detected in five patients, four men and one woman. One patient showed the disappearance of intraoperative BCR and the postoperative deterioration of bladder dysfunction. Among five patients, in whom the BCR was not detected, three underwent multiple operations and three presented with TCS. Conclusions：Reoperation and TCS are causative factors which make the detection of intraoperative BCR difficult；this is also the case in women who have severe urinary disturbances. Intraoperative disappearance of the BCR suggests the postoperative worsening of urinary function. Intraoperative BCR monitoring is useful in surgery for tumors around the conus medullaris and cauda equina, although a method enhancing BCR is necessary.

Introduction：Posterior spinal surgery is becoming increasingly common with the rapidly aging society. Changing a patient from the supine to prone position requires manpower and physical effort, and there is also the risk of neurological deterioration in the case of an unstable spine. The Jackson Table has been available in Japan since 1995, and approximately 110 devices have been used in operating theatres since then. The purpose of this study is to investigate the pros and cons of the Jackson Table for posterior spinal surgery.

Methods：We investigated 1080 cases(all of which required positional change) that utilised the Jackson Table between the dates April 2003 and August 2013. There were 717 males and 363 females with a mean age of 63.3 years (13-89 years). Complications were evaluated.

Results：All cases could change their position. There were no major complications associated with position change. Frame drop occurred in 2 cases (0.17%), metacarpal bone fracture of the operating nurse occured in one case (0.08%), and skin problems in the anterior buccal region in 15 cases (1.26%).

Conclusions：Posterior spinal surgery using the Jackson Table is useful, especially in terms of simplicity in positioning, radiolucency, and safety.

We aimed to investigate the frequency of pain worsening in patients who underwent surgical treatment for intramedullary hemangioblastoma and to elucidate the factors associated with this worsening.

Material and Method：From 2009 to 2012, we surgically treated eight patients with intramedullary hemangioblastomas. Residual pain was analyzed using the short-form of the McGill Pain Questionnaire using the Total Pain Rating Index(T-PRI)preoperatively and more than six month postoperatively. We investigated the positioning of the tumor and the surgical approach.

Results：The preoperative T-PRI scores ranged from 0 to 17 points. After the surgery, pain increased in three of eight patients. Pain increased in three out of four patients whose tumors were of the intramedullary type. In the four patients whose tumors were of the intra and extramedullary type, two patients experienced an improvement in their pain, and the remaining two reported pain that remained the same. In addition, pain increased in three of the six patients who were treated around the dorsal root entry zone (DREZ).

Discussion：Postoperative pain worsening was observed in three of the eight patients with intramedullary hemangioblastomas. Pain worsening after surgery was associated with the positioning of the tumor and the use of procedures involving the DREZ approach during the surgery.

Introduction：Correct intraoperative localization of intradural spinal tumors and also tailored dural opening is essential in surgery and can be demanding in some instances. We investigated the role of indocyanine green (ICG) fluorescence navigation to correctly localize intradural spinal tumors.

Objective：To characterize the role of indocyanine green fluorescence navigation surgery for intraoperative localization of intradural spinal tumors.

Methods：We reviewed 6 patients with spinal tumors, in which (hemi-) laminectomy or extended laminotomy was followed by ICG fluorescence navigation to determine intradural tumor margins (this involved the injection of intravenous ICG and visualization with a near-infrared fluorescence imaging handy camera). Tumor projection was verified before and after dural opening.

Results：Imaging was conducted without complications in all cases. In 5 cases, tumors were intradural extramedullary, except for one case of the dumbbell type. Identification of the tumor margins before dural opening was achieved in all cases by tumor enhancement with ICG uptake in relation to the surrounding spinal cord or nerve roots.

Conclusion：ICG fluorescence navigation surgery is a useful tool to localize the position of intradural spinal tumors. In addition to these findings we would like to explore the different pathologies and characteristics of tumor enhancement using ICG uptake.

Objective：Authors presented our surgical strategy for ventral large meningiomas to accomplish safe and precise surgical management.

Methods：21 patients who underwent surgery for spinal meningiomas over the past 7 years were included in this retrospective study. 15 out of 21 cases (71.4%) demonstrated the ventral attachment of tumor location. Ventral meningiomas were resected via a standard posterior or posterolateral approach with several modifications such as lateral oblique position, posterolateral exposure or unilateral partial facetectomy with resection of dentate ligament and spinal cord rotation technique.

Results：Macroscopically complete removal of the tumor with Simpson grade 1 or 2 was obtained in 10 of 15 cases (67%). Overall analysis of the modified McCormick Functional Schema before and after surgery demonstrated that 7 cases improved, 7 cases were deemed to be stable and 1 case deteriorated.

Discussion：Simpson grade 1 or 2 resection of the tumor may be desirable for the favorable outcome long after surgery. Surgical routes to ventral spinal meningioma should be tailored, and based on the location of the tumor, its spread, or the spinal level.

Introduction：The necessity for discectomy when magnetic resonance images(MRI)show a bulging disc before decompression surgery for lumbar canal stenosis is unclear. Our study aims to determine criteria for a discectomy.

Methods：Lumbar decompression was conducted in 89 consecutive patients with canal stenosis. We retrospectively evaluated the postoperative results(Japanese Orthopaedic Association Score (JOAS), complications, recurrence, and satisfaction). Our criteria for a discectomy were the appearance of a bulging disc in MRI accompanied by spontaneous leg pain or a positive Straight Leg Raising(SLR)test.

Results：A one year follow up was made of 79 patients(59 men and 20 women). The mean age of these patients was 70.7 years(range 46-87 years). Our criteria were met in 12 patients and they underwent a discectomy(group A). Our criteria were met in 7 patients, of which we did not discover any disc herniation at surgery(group B). A bulging disc was shown in 26 patients on MRI, but without clinical criteria(group C). No tension sign or spontaneous leg pain was found in 34 patients without disc bulging(group D). The average preoperative JOAS was 11.3, 12.7, 14.2, and 13.3 for each group respectively and significantly improved to 23.6, 22.7, 21.8 and, 21.3 respectively after surgery. Postoperative JOAS were not significantly different between groups. Satisfaction scores were 100％ for groups A and B, 92.3% for group C, and 91.2% for group D. Incidental dural tearing occurred in a patient from group A. In group C, 2 patients had recurrence, but it was caused by disease in adjacent segments.

Discussion：Unnecessary discectomy should be avoided because it can result in a damaged nerve root or incidental dural tearing from nerve root traction. A bulging disc on MRI with spontaneous leg pain or positive SLR test are useful criteria for determining the necessity of discectomy.

The purpose of this study was to evaluate the clinical results of lumbar cystic lesions treated with
microendoscopic procedure. Eight patients who underwent microendoscopic operations were analyzed(facet cysts：7 cases, discal cyst：1 case). There were seven men and one woman with an average age of 59 years. The average follow-up period was 13 months. The most common symptoms were painful radiculopathy, and the average disease duration was 3.9 months. Seven cases were performed using the unilateral approach, and one case using the midline approach. Four patients were found to have spondylolisthesis and five had hydrarthrosis of the facet joint. The average blood loss was 52ml, and the average operative time was 152 minutes. The average Japanese Orthopaedic Association score was 12.8±2.4 point preoperatively and improved to 25.8±2.6 points postoperatively. No serious perioperative complication or re-operative cases were recognized.

Although the follow-up for recurrence is necessary, microendoscopic procedure showed to be a very effective method for lumbar cystic lesions.

Cortical Bone Trajectory (CBT) has equivalent pullout and toggle characteristics if compared to the traditional trajectory pedicle screw. However there has been no research conducted on the reduction of the spondylolisthesis with the CBT screw.

This study demonstrates how the CBT screw is better at obtaining reduction in spondylolisthesis.

Up until January 2012, the reduction of spondylolisthesis were routinely performed using the CBT screw technique (total of five cases). In three of these cases, reduction failed；this was because of the loosening of the distal CBT screw during the operation. As a result since 2012 February, we penetrated the endplate with the distal CBT screw to prevent loosening. With this technique, all of the subsequent seven cases of reduction were successfully performed without loosening occuring of the distal CBT screw. This study showed that penetrating the endplate with the distal screw is a very effective method for the reduction of spondylolisthesis.

Objective：A cortical bone trajectory (CBT) is a novel pedicle screw trajectory of the lumbar
spine. Here, we analyzed the grading of CBT screw malposition on postoperative CT in our initial experience from the point of view of surgical safety.

Methods：This study included a total of 15 cases that were operated on using CBT screws in our institute between May 2012 and August 2013. Transforaminal Lumbar Interbody Fusion surgery was also carried out in 13 of the 15 cases. There were 8 males and 7 females with a mean age of 62 years. One or two-level fusion was performed in 13 cases, and multilevel fusion in two cases. Intraoperative image guidance such as fluoroscopy or CT based navigation was routinely applied. Screw position was assessed on postoperative CT.

Results：A total of 87 CBT screws were placed. Although a total of 7 screws (7.9%) were found to be malpositioned on postoperative CT, no screws resulted in neural or vascular injury. Five of seven screws were deviated shorter than mm out from the vertebral body.

Discussion：Intraoperative image guidance should be strongly recommended in the initial experience of CBT screws. Screw deviation of longer than mm may affect the surgical safety.

Purpose：After posterior spinal instrumentation is carried out(especially in the case of long spinal fusion)we sometimes need to extend to the lower fusion levels, because of either distal junctional spondylosis, fracture, deviation or loosening of pedicle screws and／or the need to perform revision surgery because of non-union after lumbosacral, spino-pelvic fixation. In these such situations, we performed revision surgery using the four rod construct for lumbosacral, spino-pelvic fixation.

Subjects and Methods：We operated on eight patients, and investigated the clinical findings. The reason for undertaking revision surgery was due to the pedicle screw loosening in all cases, and in addition to this the breakdown of the adjacent segment in one case, the adjacent vertebral fracture in two cases, and the non-union of previous lumbo-sacral fixation in one case. We placed four longitudinal rods across the lumbo-pelvic junction using the connector. Operative time, intraoperative bleeding, and complications were evaluated.

Results：Lumbosacral fixation with four iliac anchors were performed. Mean operative time was 282(225-389)minutes, and mean operative blood loss was 486(350-950)ml.

Discussion：Revision surgery using four rod constructs for lumbosacral spino-pelvic fixation offer a useful method for distal junctional kyphosis, and the non-union of lumbosacral fixation. Four rod constructs using the connector provides significantly greater fixation stability, as compared to a conventional cross-linked two-rod constructs.

Introduction：Although posterior fixation with ligamentotaxis is the standard treatment method for thoracolumbar burst fracture, inadequate reduction of the upper end plate of the vertebra has often been observed.

Objective：We introduced a novel technique to consider adequate reduction of the upper end plate.

Surgical procedure：The pedicle probe for the cervical spine is inserted within the gap between the end plate and the bony fragment, through the safety triangle that is located laterally to the superior articular process, parallel to the upper end plate. When the tip of the probe reaches the gap, the probe is tilted cranially and inserted into the fragment. Thereafter, the probe is tilted caudally, parallel to the end plate. After anteversion of the fragment is reduced, distraction and implantation are performed.

Subjects and Methods：We performed this procedure on 4 cases of lumbar burst fractures. We evaluated the fracture classifications (AO classification), neurological symptoms and recovery, occupancy rates of the spinal canal by the fragment, and angle of anteversion of the fragment in the 4 cases preoperatively, postoperatively, and at the final follow-up. Moreover, we assessed the complications of this procedure.

Results：All 4 cases were classified as A3. None of the cases had a neurological deficit or complications such as dural injury due to the procedure. The mean occupancy rate of spinal canal improved from 56.5% preoperatively to 33.3% postoperatively. The mean angle of anteversion of the fragment also improved from 27.8°preoperatively to 6.8°postoperatively.

Discussion：Reduction of lumbar burst fracture only through craniocaudal traction causes centralization of the spreading vertebral fragments, and subsequently results in inadequate reduction of the fragment that migrates into the canal due to disruption by other fragments. The main problem is the persistence of anteversion of the fragment that is not spontaneously remodeled. The use of other techniques, such as vertebroplasty and trans-pedicle reduction, does not solve this problem.

In the present report, we describe our novel technique that enables direct reduction of the fragment prior to distraction. The advantage of this technique is that the fragment can be reduced without causing disruption, and thus, it enables adequate reduction of the upper end plate.

The purpose of this study was to evaluate spinal stabilization in elderly patients with osteoporotic thoracolumbar burst fracture(pseudoarthrosis).

From Jan 2011 to Dec 2012, a total of 199 patients were admitted for the treatment of osteoporotic vertebral fracture in our institutions. Twelve patients were refractory to conservative therapy. Pedicle screw stabilization of the fractured vertebrae and transpedicular iliac bone grafting were performed in seven female patients. They had severe vertebral instability combined with middle column fracture and were included in this study. The fractured vertebrae in this study were either T12(three patients)or L1(four patients). The follow-up periods were at least 12 months.

We evaluated operation time(minutes), blood loss(millilitres), hospital stay(days), and used a Visual Analogue Scale (VAS) for back pain. Neurological deficits according to Frankel classification, parameters(vertebral wedging ratio and local kyphosis angle)on the lateral X-ray view at standing and supine position, bone union of the middle column at fractured vertebra on CT scan, and complications were also measured.

The operation time was a mean of 251 minutes. The blood loss was a mean of 103ml. The hospital stay was a mean of 66 days. VAS for back pain was significantly decreased postoperatively. Neurological deficits(Frankel C and D)were found in all four patients. Preoperative vertebral wedging ratio on the lateral X-ray view at standing and supine position were 51.0±17.4％ and 15.2±9.3％, respectively. Postoperative vertebral wedging ratio at standing and supine position were 26.6±20.2％ and 25.9±20.3％, respectively. Preoperative local kyphosis angle on the lateral X-ray view at standing and supine position were 7.0±7.3° and −3.1±4.4°, respectively. Postoperative local kyphosis angle at standing and supine position were 3.8±12.6° and −0.2±5.9°, respectively. Both intra- and inter-vertebral instability were significantly improved postoperatively. Bony union of the middle column were successfully achieved in all patients in a mean of 4.5 months. No-one had donor site pain at discharge.

The results indicated that inter-vertebral stability is as important as intra-vertebral stability to provide pain relief and also for the improvement of neurological deficits in elderly patients with osteoporotic thoracolumbar burst fractures.

In the past it was common to treat vertebral fractures secondary to osteoporosis conservatively. However BKP has since been covered by Japanese Health Insurance and subsequently this technique was introduced to our hospital in September 2012. We saw good results in the short term postoperative course of 12 patients.

Our study also demonstrated a significant improvement of postoperative pain from 10 to 1 using our pain scoring system.

There were intraoperative complications in two patients, but neither complication was found to be clinically significant.

With the need for two X-ray tables, this did not result in a shortened operative duration, but still allowed for a safe and effective operating environment.

Since 2005, we have performed muscle-preserving selective laminectomy on 18 patients who suffered myelopathy due to single-level cervical disc herniation. The average age was 47.2 years, ranging between 33 and 66 years. The average follow up period was 24.9 months. Operation time averaged 127.4 minutes and blood loss 9.5 grams. Pre- and post-operative C2-7 angles averaged 4.0° and 8.1°. Pre- and post-operative Japanese Orthopaedic Association scores averaged 13.1 and 15.8 with an average recovery rate of 66.5％. None of the patients complained of residual neck pain 3 months after surgery. It has been reported that adjacent segmental disease was one of the distinct postoperative problems of anterior cervical fusion. As compared to cervical spondylotic myelopathy, cervical disc herniation is more common amongst younger patients whose postoperative life remains long enough for the development of adjacent segment disease. Musclepreserving selective laminectomy for single-level cervical disc herniation successfully maintained mobility and stability of the cervical spine, probably reducing the incidence of adjacent segment disease by minimizing damage to the posterior stabilizing structures. No patients to date had problems with adjacent mobile segments to the affected disc level. Selective laminectomy provided satisfactory neurological recovery which was found to be comparable to reported outcomes of anterior procedures.

The purpose of this study is to elucidate correlation among the range of cervical motions, cervical disc degeneration, and cervical curvature by analyzing X-rays and MRI taken from 100 asymptomatic subjects. 100 asymptomatic volunteers underwent X-rays and 3.0 Tesla MR scanning. There were 20 subjects in each decade of age from twenties to sixties. Dynamic lateral Xrays were taken to measure range of movement (ROM). ROM averaged 75.5° in the twenties age group, 72.8° in the thirties, 61.5° in the forties, 52.5° in the fifties and 48.6° in the sixties age group. ROM significantly decreased linearly with age. ROM averaged 66.8° in 69 subjects without the reduction of disc space, 61.8° in 3 subjects with the reduction at C3/4, 56.6° in one subject at C4/5, 56.3° in 10 at C5/6 and 44.1° in 9 at C6/7. There is a statistically significant difference only between subjects without the reduction and those with the reduction at C6/7. Mobility of the neck decreased linearly with aging. Type of cervical curvature did not influence the mobility. It was suggested that disc degeneration and narrowed disc space were the factors causing restriction of neck movements. The disc height reduction at C6/7 was the most significant factor causing the restriction.

A 52 year-old woman experienced axial pain and numbness in the right forearm. A 3D MRI with Constructive Interference in Steady State (CISS) revealed expansion of the CSF space, and compression of the spinal cord from C7/T1 to T3/4. C7 laminoplasty and T1-T3 laminectomy were performed following resection of the subdural arachnoid cyst. Her symptoms were resolved immediately after the operation.