Manabu Sasaki

The Effect of Laser Irradiation for Nucleus Pulposus: an Experimental Study

Abstract Background: The radicular pain caused by disc herniation can be explained by two mechanisms: the compression of the nerve root by the herniated disc or the irritation of the nerve root due to chemical factors. Percutaneous laser disc decompression (PLDD) was introduced for the treatment of lumbar disc hernias in the 1980s. Decompression of the nerve root is assumed to be an effective therapeutic mechanism for PLDD. However, laser irradiation might reduce the chemical factors that cause nerve root irritation by altering intra–disc proteins. We used nerve conduction velocities (NCV) and levels of two chemical factors to evaluate the differences between the two groups in this in vivo study. Methods: All rabbits had the nerve root in contact with the leakage from the nucleus pulposus. One group underwent laser irradiation for the leaking nucleus pulposus including the incision site of the disc and nucleus pulposus itself. The levels of two chemical factors, prostaglandin E2 and phospholipase E2, in the intervertebral disc were measured before and after laser irradiation. Results: NCV in the laser–irradiated group was significantly faster than in the non–laser–irradiated group. The levels of chemical factors were significantly reduced after laser irradiation. Conclusions: One of the mechanisms thought to be responsible for PLDDs effectiveness is a decrease in the chemical factors through protein alteration in the intervertebral disc by laser irradiation.

Structural characterization and chromosomal localization of the MAGE-E1 gene

Genes of the melanoma-associated antigen (MAGE) family are characterized by the expression of tumor antigens on a malignant melanoma recognized by autologous cytolytic T lymphocytes. We have previously identified novel members of the MAGE gene family expressed in human glioma and named them MAGE-E1a-c. In the present study, we have revealed the genomic structure of MAGE-E1 by sequence analysis of a human chromosome bacterial artificial chromosome clone containing the MAGE-E1 gene. The MAGE-E1 gene is composed of 13 exons, and three of these (exon 2, exon 3 and exon 12) are alternatively spliced in each variant (E1a-c). The open reading frame encoding the MAGE-E1 peptides initiates in exon 2 and ends in exon 13. We have also demonstrated that the MAGE-E1 gene is located in Xp11 through the analysis of radiation hybrid panels. The genomic structure of MAGE-E1 is markedly similar to that of MAGE-D and its chromosomal locus is also identical to that of MAGE-D, but these features contrast with those of other MAGEs. These results suggest that MAGE-D and -E1 may be evolutionarily distant from other members of the MAGE family, and the two may be ancestral genes for the others.

Middle-term surgical outcomes of microscopic posterior decompression for far-out syndrome.

OBJECTIVE Far-out syndrome (FOS) is a rare incident caused by L5 nerve root entrapment in the far-out area, the L5-S1 extraforaminal area between the transverse process and the sacral ala. The purpose of this study is to disclose the middle-term surgical outcomes of microscopic posterior decompression in the far-out area (MPDFA). MATERIAL AND METHODS From June 2008 to November 2010, eight patients with FOS (six men and two women, mean age 65.4 years) were treated with MPDFA. Their chief complaint was leg pain in the L5 nerve root distribution area. Nerve root impingements in the far-out area were confirmed by magnetic resonance imaging, computed tomography and selective radiculography. Indications for MPDFA were given when pain was uncontrollable with conservative treatments for more than 1 month. MPDFA was performed according to the following procedure: a 4-to-5-cm skin incision was made just above the far-out area. The far-out area was exposed using Wiltses intermuscular approach. The nerve root was decompressed with partial resection of the transverse process and the sacral ala, and removal of the iliolumbar ligament. Surgical outcomes were evaluated at periodical examinations with the Japanese Orthopedic Score (JOA) and a Visual Analogue Scale (VAS) of the leg pain. The mean follow-up period was 24.3 months (ranging from 12 to 40 months). RESULTS All patients had reduced radicular leg pain after their operations. The mean postoperative hospital stay was 11.4 days, and the patients returned to their normal activities of daily living immediately after discharge. Both JOA and the VAS scores improved after surgery. The scores temporarily worsened in two patients with degenerative scoliosis; the worsening was attributed not to recurrence of the radiculopathy but to pain arising from knee arthropathy. The scores were maintained in the other patients at least until the final examinations during the follow-up. CONCLUSION MPDFA is a less-invasive surgery for treating FOS and can provide a good middle-term surgical outcome.

Report of a familial case of proatlas segmentation abnormality with late clinical onset

Although proatlas segmentation abnormalities as developmental remnants around the foramen magnum have been reported in postmortem studies, they are rarely documented in a clinical setting. This report details the clinical and radiological characteristics of a rare case of proatlas segmentation abnormalities with clinical onset during the seventh decade of life. This case was suspected to have a familial factor. We also review the literature regarding this condition.

Anterior transarticular screw fixation as a conventional operation for rigid stabilization

Background: Anterior transarticular screw (ATS) fixation is a useful surgical option for atlantoaxial (AA) stabilization. This report presents a revised ATS method for AA fusion. Methods: A 79-year-old male presented with AA instability attributed both to an old odontoid fracture and severe degeneration of the lateral atlantoaxial joints (LAAJs). ATS fixation was performed through the conventional anterior cervical approach. The longest screw trajectories were planned preoperatively using multiplanar reconstruction computed tomography (CT) scans, with entry points of the screws situated at the midpoint on the inferior border of the axial body. The surgical exposure was limited to opening at the entry points alone. Our retractor of choice was the Cusco speculum; it sufficiently secured space for utilizing the required instruments for screw placement while offering sufficient protection of soft tissues. Cannulated full-threaded bicortical screws stabilized the LAAJs. Screw insertion required a significant amount of coronal angulation up to the superior articular process of the atlas under open-mouth and lateral fluoroscopy image guidance. After ATS fixation, bone grafting was performed between the posterior laminae of the axis and the atlas through a conventional posterior approach. Results: Bony fusion between the atlas and the axis was confirmed radiographically. Arthrodesis of the LAAJs occurred despite no bone grafting. Conclusions: Rigid fixation of the LAAJs was obtained by our ATS technique, indicating that it is an alternative method for AA fixation when posterior rigid internal fixation is not applicable.

Long-term Surgical Outcomes of Symptomatic Perineural (Tarlov) Cysts with Occlusion of the Cyst Orifice Using Autologous Fat Tissue

Introduction:Lumbosacral perineural (Tarlov) cysts (TCs) are rare and usually asymptomatic. However, these cysts occasionally cause neuralgia or bowel/bladder dysfunction. We surgically treated symptomatic TCs with occlusion of the cyst orifice using autologous fat tissue. This report presents the long-term surgical outcomes using this method. Materials and Methods:Six consecutive cases with symptomatic TCs were included in this study. Patients were initially examined with magnetic resonance imaging (MRI) and treated conservatively for at least 1 month. Preoperative CT myelograms in all patients showed pooling of contrast medium in the cyst. Surgery was performed as follows:after laminectomy at the S1‒S2 level, the cyst wall was dissected and penetrated. The orifice of the cyst operated as a ball valve for cerebrospinal fluid and was occluded with autologous fat tissue that was sutured to the cyst wall. The visual analogue scale (VAS) score for pain in the buttock and/or posterior thigh was recorded before and after surgery. Results:All patients were female, and the mean age was 63.3 years. Preoperative symptoms were sacrococcygeal pain in 5 cases, sciatic pain in 2, and bladder dysfunction in 1. The mean duration between onset and definitive diagnosis was 23.7 months. All cysts were located at the sacral level including S2. Three cases had solitary lesions and the other 3 had multiple lesions. Cyst sizes ranged from 7 to 30 mm. The average postoperative follow‒up period was 37.8 months. The mean preoperative VAS score was 91.7, and gradually decreased to 33.3 at 6 months. The score was stable from the 6‒month examination to the final follow‒up. Postoperative MRI showed that the cysts decreased in size. A complication of surgery was mild bowel/bladder dysfunction in 1 case. During follow-up, no recurrence of symptoms or cyst regrowth was observed. Conclusion:For symptomatic TCs, closing the orifice with fat tissue provides good surgical outcomes. (Received:September 29, 2017;accepted November 20, 2017)

Adult Case of Atlantoaxial Rotatory Fixation Treated with In Situ Fixation Using an Unusual Posterior Instrumentation Construct

Atlantoaxial rotatory fixation (AARF) occurs commonly in children who have undergone trauma. It is usually corrected with conservative therapy. In this report, however, the patient was an adult with AARF who was treated surgically. A 64-year-old woman presented with a 1-year history of spastic gait and hand clumsiness. Imaging studies revealed the presence of AARF, os odontoideum, and severe spinal cord compression at that spinal level. As the AARF had not been responded to head traction with a halo device, we decided to treat the patient with in situ posterior fixation. Because the rigid dislocation was present between the atlas and the axis, we were forced to make an unusual instrumentation construct. Neurological symptoms other than hand numbness diminished after the surgery, and arthrodesis was obtained between the occiput and the axis. It should be noted that surgical planning for posterior instrumentation construct is required when rigid AARF is treated surgically.

Spontaneous Regression of Inflammatory Pseudotumor in the Cauda Equina: A Case Report

Spinal intradural extramedullary inflammatory pseudotumor (IPT) is an extremely rare entity. Spontaneous shrinking of a spinal IPT has never been reported. A case of an IPT of the cauda equina that regressed spontaneously is presented. A 78-year-old woman presented with hypoesthesia of both lower legs in the L4 nerve root distribution and motor weakness of the right leg. Preoperative CT myelography and MRI showed two tumor-like lesions located at T12-L1 and L2-3. The lesion at the T12-L1 level appeared to encase several nerve roots. The preoperative diagnosis was ependymoma, schwannoma, or malignant lymphoma. The tumors were biopsied. In the operation, the lesion turned out to consist of swollen and adherent nerve roots. On histopathological examination of the biopsied nerve roots, they were diagnosed as IPT. The patient’s symptoms improved gradually without any treatment after the operation. The IPTs regressed on the postoperative MR images and disappeared at one year. This is the first report of spontaneous regression of an IPT in the spinal region. IPT should be considered in the differential diagnosis of a tumor that appears to involve several nerve roots on preoperative imaging, but surgery is necessary for diagnosis. Complete resection is not absolutely required if an intraoperative pathological diagnosis of the frozen section reveals IPT.

Groin Pain Caused by L3 and L4 Radiculopathy

Background: Previous reports have described patients with groin pain induced by lumbar radiculopathy below the L3 spinal level, but this type of groin pain has not been studied in detail. This retrospective clinical study investigated the possibility of groin pain caused by lumbar radiculopathy below the L3 spinal level. Methods: We reviewed the clinical records of 210 consecutive patients who were surgically treated for singlelevel lumbar radiculopathy between June 2005 and September 2012. We examined the spinal level of the affected nerve root, clinical symptoms, and surgical outcomes based on the Japanese Orthopedic Association (JOA) score for lumbar diseases and a visual analog scale (VAS) for leg pain. Results: The 210 patients underwent surgery for single-level lumbar radiculopathy due to L3 radiculopathy (7 patients), L4 radiculopathy (20), L5 radiculopathy (127), or S1 radiculopathy (56). Groin pain was experienced by 8 patients (3 patients with L3 and 5 with L4 radiculopathy). Most of these 8 patients also experienced pain in the anterior thigh (6 patients) or knee (5 patients) regions. The pain experienced by these patients was relieved by surgical decompression of the affected nerve roots. The JOA and VAS scores showed significant improvement postoperatively. The mean postoperative follow-up period was 19.6 months (range, 6–40 months), during which time none of the patients required additional treatment for groin pain. Conclusions: L3 or L4 radiculopathy should be considered during the examination of patients with groin pain and radicular leg pain.