Atlantoaxial Stabilization Using C1 Lateral Mass and C2 Pedicle/Translaminar Screw Fixation by Intraoperative C1- and C2-Direct-Captured Navigation with Preoperative Computed Tomography Images.

In C1-C2 posterior fixation, the C1 lateral mass and C2 pedicle/translaminar screw insertion under spine navigation have been used frequently. To avoid the risk of neurovascular damage in atlantoaxial stabilization, we assessed the safety and effectiveness of a preoperative computed tomography (CT) image-based navigation system with intraoperative independent C1 and C2 vertebral registration. It is ideal when a reference frame can be linked directly to the C1 posterior arch for C1-direct-captured navigation, but there is a mechanical challenge. A new spine clamp-tracker system was implemented recently, which allows reliable C1- and C2- direct-captured navigation in nine patients with traumatic C2 fractures. In this way, there was no misalignment of C1-C2 screws. C1 lateral mass screws were used except for one case, and translaminar screws were primarily used as an anchor for C2. The C1 lateral mass screw locations, which are 19 mm laterally from the C1 posterior arch's center, are taken to be constant. However, there is one unusual circumstance in which using a C1 laminar hook instead of a C1 lateral mass screw appears to be a beneficial substitute. The increase of surgical accuracy for posterior C1-C2 screw fixation without cost constraints is significantly facilitated by intraoperative C1- and C2-direct-captured navigation with preoperative computed CT images.

[A Case of Bilateral Trigeminal Neuralgia and the Possible Onset Mechanisms Based on the Operative Findings].

Several cases of bilateral trigeminal neuralgia(TN)have been reported;however, the possible onset mechanism has rarely been discussed. We encountered a case of bilateral TN occurring in two stages. A 64-year-old woman presented with left TN. Magnetic resonance imaging showed the transverse pontine vein adhering to the left trigeminal root and superior cerebellar artery adhering to the right trigeminal root;however, no symptoms were noted. Immediately after microvascular decompression(MVD)on the left side, TN disappeared completely. However, 2 years postoperatively, the patient presented with right TN. The second MVD surgery revealed that the right cerebellar surface severely adhered to the dura mater, particularly under the surface of the tentorium. The arachnoid membrane at the cerebellopontine angle was slightly adhered. The patient was completely free from pain after the second MVD. The intraoperative findings suggested that the brain stem may have shifted and the cerebellopontine cistern may have narrowed because of cerebellar adhesion to the surrounding structures and arachnoid adhesion. We speculate that such structural changes in the posterior fossa after the first operation may have caused the asymptomatic vascular adhesion to change into the symptomatic offending adhesion over time.

History and Evolution of Laminoplasty.

Techniques of expansive laminoplasty for degenerative cervical myelopathy and ossified posterior longitudinal ligament are described, focusing on the history of the surgical procedure. Laminectomy was the only approach for posterior decompression before Japanese orthopedic surgeons introduced laminoplasty from the 1970s to the 1980s to overcome the poor outcomes of laminectomy. Recent laminoplasty techniques offer less invasive maneuvers to the posterior cervical muscle structures to reduce axial neck pain and to obtain better functional outcome, but every operation is carried out based on the unchanged initial concept. Some recent attempts to improve the surgical results are also discussed.

Clinical study of C3-C4 level surgical cases of cervical spondylosis.

OBJECTIVE: The purpose of this study was to elucidate the pathological characteristics of C3-C4 cervical spondylotic myelopathy (CSM). METHODS: Single-level anterior cervical discectomy and fusion (ACDF) was performed at C3-C4 in 53 patients (38 men, 15 women). The mean duration of preoperative symptoms was 6.0 months. Fifty-three non C3-C4 ACDF patients of our random sample of ACDF patients were compared to the C3-C4 ACDF patients. Clinical outcomes were assessed according to the Japanese Orthopedic Association score (JOA score), the Neurosurgical Cervical Spine Scale (NCSS), and the Nurick scale. And radiological findings including C2-C7 lordosis, C3-C4 range of intervertebral motion (ROM), C2-C7 ROM, and C3-C4%ROM in the cervical spine were evaluated in both groups. RESULTS: The recovery rates of JOA score and the NCSS in C3-C4 ACDF patients were 62.5% and 62.1%, respectively. The radiological study of C3-C4 ACDF patients showed that they had significant cervical lordosis, and cervical motion was dependent on the C3-C4 segment, which accounted for 39.8% of C2-C7 ROM (total motion). CONCLUSION: In C3-C4 ACDF patients, not only static factors, but dynamic factors (instability) at the C3-C4 level contributed to the major causes of CSM.

Surgical consideration of cervical dumbbell tumors.

BACKGROUND: Nineteen patients with cervical dumbbell tumors treated surgically were analyzed retrospectively. METHODS: Surgical strategies for dumbbell tumor were discussed from the perspective of safe, less-invasive surgery. RESULTS: Patients included 6 men and 13 women, with a mean age at the time of surgery of 48.3 years (range, 25-70 years). Underlying pathologies included 16 schwannomas, 2 neurofibromas, and 1 double tumor (schwannoma and meningioma). According to Eden's classification, one patient was classified as Type 1, 5 as Type 2, 8 as Type 3, and 5 as Type 4. In 13 cases, tumors were excised through the posterior approach alone, compared to five cases using the anterior approach. One case was excised using combined anterior and posterior approaches. Facetectomy was not performed in 18 cases. In one case, the facet joint on one side had already destroyed and needed instrumentation. Tumors were totally excised in all cases. Postoperatively, the patients did not display any further neurological deficit, with the exception of transient radiculopathy in two patients. Major surgical complications and cerebrospinal fluid leakage were not seen. Tumor recurrence and spinal segmental instability were not found during follow-up period (mean, 41.6 months). CONCLUSIONS: Dumbbell tumor surgery requires sufficient debulking of the epidural and paravertebral mass, using intraoperative nerve stimulation and Doppler ultrasonography to detect the vertebral artery. When using a posterior approach, recapping laminoplasty using an ultrasonic bone curette is very useful to remove tumor without sacrificing facet joints.

Thoracolumbar extradural arachnoid cyst--three surgical case reports.

Three cases of symptomatic extradural arachnoid cyst were treated by surgery. Total excision of the cyst followed by tight closure of the fistula by suture was achieved in all 3 cases. Surgery improved the neurological deficits but urinary incontinence persisted in all three patients. Obliteration of the fistula is considered to be important at surgery from the etiological perspective of the cyst. There are many surgical options, but surgical removal of the cyst and obliteration of the communication usually leads to prompt improvement in neurological deficits. Instability, malalignment, and worsening scoliosis are well-recognized postoperative complications of excessive laminotomy, but the exposure should be wide enough to cover the cyst completely at the operation. Wide exposure of the entire cyst is preferable to avoid missing the fistula and to identify any adhesions or fistula between the cyst and the dura. Identification of the fistula location based on preoperative imaging studies is also important.

Percutaneous endoscopic lumbar discectomy - early clinical experience.

We report our early clinical experience with percutaneous endoscopic lumbar discectomy (PELD) for herniated nucleus pulposus (HNP) in the lumbar spine. We introduced PELD to our clinical practice in June 2009. A total of 311 patients with degenerative lumbar spine disease were treated in our hospital up to August 2011. Thirty-seven patients with lumbar HNP were treated by PELD. PELD was carried out under local anesthesia, and the endoscope was continuously irrigated with saline. Twenty-eight patients were treated through the transforaminal approach, 5 were treated through the interlaminar approach, and 4 were treated through the extraforaminal approach. Surgery was discontinued due to uncontrollable intraoperative pain or anatomical inaccessibility in one case of the interlaminar approach and 2 cases of the extraforaminal approach. In the other 34 patients, the elapsed time of surgery was 34 to 103 minutes (mean 62.4 minutes). Extracorporeal blood loss was insignificant. Immediate symptom relief was achieved in all patients, and postoperative magnetic resonance imaging revealed sufficient removal of the HNP. The length of the postoperative hospital stay was 1 or 2 days in all patients. The surgical method of PELD is completely different from percutaneous nucleotomy, and the aim is to directly remove the HNP with minimum damage to the musculoskeletal structure. Although this study is based on our early clinical outcomes, PELD seemed to be a promising minimally invasive surgery for HNP in the lumbar spine.

Recapping hemilaminoplasty for spinal surgical disorders using ultrasonic bone curette.

OBJECTIVE: The authors present a novel method of the recapping hemilaminoplasty in a retrospective study of patients with spinal surgical disorders. This report describes the surgical technique and the results of hemilaminoplasty using an ultrasonic bone curette. The aim of this study was to examine the safety and effectiveness of the hemilaminoplasty technique with ultrasonic bone curette. METHODS: Between April 2003 and July 2011, 33 patients with various spinal diseases (17 spinal tumors, 5 dural arteriovenous fistulas, 3 syringomyelia, 2 sacral perineural cysts, and 2 arachnoid cysts) were treated microsurgically by using an ultrasonic bone curette with scalpel blade and lightweight handpiece. The ultrasonic bone curette was used for division of lamina. After resection of the lesion, the excised lamina was replaced exactly in situ to its original anatomic position with a titanium plate and screw. Additional fusion technique was not required and the device was easy to handle. All patients were observed both neurologically and radiologically by dynamic plain radiographs and computed tomography (CT) scan. RESULTS: The operation was performed successfully and there were no instrument-related complications such as dural laceration, nerve root injury, and vessels injury. The mean number of resected and restored lamina was 1.7. CT confirmed primary bone fusion in all patients by 12 months after surgery. CONCLUSION: The ultrasonic bone curette is a useful instrument for recapping hemilaminoplasty in various spinal surgeries. This method allows anatomical reconstruction of the excised bone to preserve the posterior surrounding tissues.

ß-Tricalcium phosphate promotes bony fusion after anterior cervical discectomy and fusion using titanium cages.

STUDY DESIGN: Retrospective consecutive cohort study. OBJECTIVE: To study the effectiveness of ß-tricalcium phosphate (ß-TCP) granules as a packing material in the titanium cages for anterior cervical discectomy and fusion (ACDF), compared with the conventional hydroxyapatite (HA) granules. SUMMARY OF BACKGROUND DATA: ACDF using titanium cages is a standard procedure for the treatment of cervical spinal degenerative diseases. Synthetic bone substitutes are widely used to pack the titanium cage to augment intervertebral bony fusion, but the efficacy has not been confirmed. METHODS: Fusion condition was evaluated on lateral radiographs and computed tomography. Complete fusion of the treated segments was defined by three criteria: movement of the spinous process at flexion and extension positions of less than 3 mm, bony bridging between vertebral bodies, and absence of the halo around the titanium cage. The evaluation was performed at 6 months, 1 year, and 2 years after surgery. RESULTS: Intervertebral fusion was studied in patients who underwent ACDF using ß-TCP (93 segments of 57 patients) or HA (72 segments of 48 patients) packing of cylindrical titanium cages. Complete fusion rate at 6 months and 1 year was significantly better in the ß-TCP group (46% at 6 months and 69% at 1 year) than in the HA group (24% at 6 months and 49% at 1 year), but the rate was similar at 2 years in the ß-TCP group (94%) and the HA group (90%). There were no material-related adverse effects. CONCLUSION: Satisfactory final fusion rates were obtained after ACDF using both ß-TCP- and HA-packed titanium cages. ß-TCP showed higher fusion rate in the early stage after surgery and can be recommended as a bone substitute for ACDF with titanium cages.

Minimally invasive central corpectomy for ossified posterior longitudinal ligament in the cervical spine.

Minimally invasive central corpectomy (MICC) for cervical segmental ossified posterior longitudinal ligament (OPLL) is described. The procedure of MICC includes upper- or lower-half central corpectomy of the involved cervical spine, transdiscal decompression of the adjacent disc level, dissection and partial removal of the OPLL, removal of the OPLL behind the vertebral body via these windows, and fusion with cylindrical titanium cages. Anterior plate fixation is not necessary. From January 2008 to December 2009 we surgically treated three patients with cervical OPLL by MICC. All three patients showed remarkable improvement of their symptoms within a few days after the operation. No neurological or radiological complication was observed during that period. MICC is beneficial in avoiding complete corpectomy and long fusion, usage of an anterior plate, and usage of a large external orthosis. MICC also reduces the risk of postoperative esophageal perforation due to a screw backing out of the plate.

Long term outcome and adjacent disc degeneration after anterior cervical discectomy and fusion with titanium cylindrical cages.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) is widely performed for the treatment of cervical spinal degenerative disease. Autogenic or allogenic bone grafts are used for interbody fusion with satisfactory long term outcomes. However, harvest of the autograft causes donor site complications and allograft is associated with low fusion rate. Threaded titanium cages (TC) have recently been introduced to cope with these disadvantages, but there is little evidence of long term results. METHODS: The long term outcome was studied after ACDF using TC. Clinical and imaging follow up was performed in 41 patients for at least 5 years (range 5-8.3 years). New computer-assisted measurement methods for radiographs are proposed. FINDINGS: ACDF with TC achieved 80% excellent or good outcome by Odom's criteria, 95% fusion rate, and few minor complications. Asymptomatic adjacent disc degeneration was detected in 50% of the patients by our measurement methods. However, symptomatic adjacent disc degeneration occurred in 5% of the patients and only 2% required additional surgery. CONCLUSIONS: These results are comparable or better than those after ACDF with autograft or allograft. ACDF with TC can achieve rigid fixation and provide good long term results.

Angiographically occult spinal dural arteriovenous fistula located using selective computed tomography angiography. Case report.

Spinal dural arteriovenous fistula (DAVF) is the most common type of spinal arteriovenous malformation and may cause progressive myelopathy but is usually treatable in the early stages by direct surgery or intravascular embolization. Selective spinal angiography has been the gold standard for diagnosis, but angiographically occult DAVF is not uncommon. A 67-year-old man presented with a 2-year history of progressive paraparesis. Magnetic resonance (MR) imaging demonstrated segmental atrophy of the spinal cord and dilated coronary veins on the dorsal surface of the spinal cord. A DAVF was suspected, but repeated selective angiography failed to demonstrate the fistula. Findings from spoiled gradient echo MR imaging suggested that the draining vein flowed into the dilated venous plexus at the T-9 level. Selective computed tomography (CT) angiography of the right T-9 intercostal artery confirmed the location of the fistula. The authors successfully occluded the draining vein through surgery, and they observed that the fistula was low flow. The patient exhibited improvement in his symptoms, and postoperative MR imaging confirmed closure of the fistula. Selective CT angiography is useful in locating the draining vein of angiographically occult DAVF and therefore minimizing the extent of the surgical procedure.

Pathophysiology of cerebral circulatory disorders in idiopathic normal pressure hydrocephalus.

This study was conducted to elucidate the pathologic conditions of cerebral circulatory disorders in idiopathic normal pressure hydrocephalus (iNPH). Among 44 possible iNPH patients, 40 patients underwent shunt surgery based on diagnostic flow charts plotted by the Southern Tohoku method and were evaluated to be shunt-effective at the end of the first post-surgical month. The cerebral blood flow (CBF) was measured by N-isopropyl-((123)I)-P-iodo-amphetamine single photon emission computed tomography (mean, mCBF; cortical region, cCBF; thalamus-basal ganglia region, tbCBF on autoradiography [ARG] method) and the perfusion patterns of the cerebral cortex were measured based on three-dimensional stereotactic surface projection (3D-SSP) Z-score images, before and 1 month after the surgery in all 40 subjects. The mCBF rose significantly from 32.1 +/- 2.74 ml/100 g/min before surgery to 39.8 +/- 3.02 ml/100 g/min after surgery (p < 0.03). Investigation of the change of CBF revealed reductions in the cCBF (3 cases), tbCBF (9 cases), and cCBF + tbCBF (28 cases), with the reduced-cCBF group totaling 31 cases and the reduced-tbCBF group totaling 37 cases. Investigation of cerebral cortex hypoperfusion by 3D-SSP Z-score revealed 31 cases with hypoperfusion (frontal lobe type [19 cases], occipitotemporal lobe type [5 cases], mixed type [7 cases]) and nine cases with cortical normoperfusion (N). The pattern of reduction of the cortical blood flow on ARG method was favorably correlated with the pattern of hypoperfusion of the cerebral cortex on 3D-SSP Z-score images before surgery. A reduction of blood flow was found in the thalamus-basal ganglia region of all N type cases. The blood flow improved in 19 of 31 (61.3%) cases of the reduced-cCBF group and in 32 of 37 (86.5%) cases of the reduced-tbCBF group. All of the cases without detectable improvement exhibited increased blood flow in non-reduction areas. Investigation of the hypoperfusion patterns of the cerebral cortex on 3D-SSP Z-score images, revealed a reduction or disappearance of the hypoperfusion site in 19 of 31 (61.3%) cases, either no-change or a shift of the hypoperfusion site in 12 of 31 (38.7%) cases, and a correlation between the pattern of cortical blood flow reduction on ARG method and the pattern of cerebral cortex hypoperfusion on 3D-SSP Z-score images after surgery. Cerebral circulatory disorders in iNPH manifest as either of two pathophysiological conditions: the "circulatory disorder of the cerebral cortical region" and the "circulatory disorder of the thalamus-basal ganglia region." Various patterns develop according to the disease stage.

Novel dural closure technique using polyglactin acid sheet prevents cerebrospinal fluid leakage after spinal surgery.

OBJECTIVE: Extradural or subcutaneous cerebrospinal fluid (CSF) leakage is a common complication after spinal surgery and is associated with the risks of poor wound healing, meningitis, and pseudomeningocele. Numerous methods to prevent postoperative CSF leakage are available, but pressure-tight dural closure remains difficult, especially with synthetic surgical membranes. The efficacy of a novel dural closure technique was assessed by detecting extradural or subcutaneous CSF leakage on magnetic resonance imaging. METHODS: The novel dural closure technique using absorbable polyglactin acid sheet and fibrin glue and the conventional procedure using only fibrin glue were evaluated retrospectively by identifying extradural or subcutaneous CSF leakage on magnetic resonance imaging scans in the acute (2-7 d) and chronic (3-6 mo) postoperative stages after spinal intradural surgery in 53 patients. RESULTS: The incidence of extradural and subcutaneous CSF leakage was significantly lower (P < 0.05) in the acute (20%) and chronic (0%) stages using polyglactin acid sheet and fibrin glue in 15 patients compared with that in the acute (81%) and chronic (24%) stages using only fibrin glue in 38 patients. One patient in the fibrin glue-only group required repair surgery for cutaneous CSF leakage. CONCLUSION: The combination of polyglactin acid sheet and fibrin glue can achieve water-tight closure after spinal intradural surgery and can minimize the risk of intractable postoperative CSF leakage. This simple, economical technique is recommended for dural closure after spinal intradural surgery.

[Four cases of spontaneous spinal epidural hematoma].

Spontaneous spinal epidural hematoma (SSEH) is a rare clinical entity. Although approximately 500 cases have been reported, controversy exists concerning timing of the treatment and the validity of decompression surgery. We recently encountered four cases of SSEH. Evacuation of the hematoma was carried out in two patients with severe or persistent neurological deficits. Other two patients were treated conservatively because of the rapid resolution of the symptoms. All four patients improved after the treatment; three patients fully recovered and one patient required rehabilitation for moderate quadriparesis. Many previous reports recommended decompression surgery within 48 hours after the onset, however, one patient in our series fully recovered after surgery 4 days after the onset. We reviewed 183 operative cases of SSEH with incomplete neurological deficits in the literature and found that 93% of the patients who underwent surgery more than 48 hours after symptom onset showed good neurological recovery. Conservative treatment should be undertaken for rapidly improving patients, but surgical intervention should be considered in symptomatic patients regardless of the time from the onset.

Evaluation of anorectal function in patients with tethered cord syndrome: saline enema test and fecoflowmetry.

OBJECT: Disturbance in anorectal function is a major factor restricting the activities of daily living in patients with spinal cord disorders. To detect changes in anorectal motilities due to a tethered spinal cord, anorectal functions were evaluated using a saline enema test and fecoflowmetry before and after patients underwent untethering surgery. METHODS: The bowel functions in five patients with a tethered cord syndrome (TCS) were evaluated by performing a saline enema test and fecoflowmetry. The contractile activity of the rectum, the volume of infused saline tolerated in the rectum, anal canal pressure, and the ability to evacuate rectal content were examined. The characteristic findings in anorectal motility studies conducted in patients with TCS were a hyperactive rectum, diminished rectal saline-retention ability, and diminished maximal flow in saline evacuation. A hyperactive rectum was considered to be a major contributing factor to fecal incontinence. In one asymptomatic patient diminished anal squeezing pressure was exhibited and was incontinent to liquid preoperatively, but recovered after surgery. Two patients who underwent surgery for myeloschisis as infants complained of progressive fecal incontinence when they became adolescents. In one patient fecal incontinence improved but in another patient no improvement was observed after untethering surgery. CONCLUSIONS: Fecodynamic studies allow the detection of neurogenic disturbances of the anorectum in symptomatic and also in asymptomatic patients with TCS. More attention should be paid to the anorectal functions of patients with TCS.

Spinal cord edema preceding syringomyelia associated with Chiari I malformation--case report.

A 38-year-old woman with Chiari I malformation presented with spinal cord edema preceding syringomyelia manifesting as a 5-month history of nuchal pain and numbness of the upper extremities. Magnetic resonance imaging showed spinal cord edema, a poorly defined syrinx at the C-2 to T-2 levels, and distorted cerebellar tonsils. Computed tomography revealed cerebrospinal fluid (CSF) density in the center of spinal cord edema, and positron emission tomography revealed no uptake of L-[methyl-11C]methionine, indicating a non-neoplastic lesion. Craniocervical decompression achieved excellent clinical and neuroradiological outcomes. The success of surgical treatment supports the theory that patients with Chiari I malformation have increased transmural flow of CSF, causing spinal cord edema that progresses to syringomyelia. Early treatment of patients with spinal cord edema is indicated to prevent permanent spinal cord injury due to progressive syringomyelia.