Communicating hydrocephalus after resection of a meningioma ventral to the foramen magnum.

Background: Tumors in or near the foramen magnum may cause communicating or non-communicating hydrocephalus (HC), depending on their size and location. Here, an 81-year-old female developed communicating HC following the resection of a meningioma ventral to the foramen magnum. Case Description: An 81-year-old female presented with numbness in the left neck and left hemiparesis. The magnetic resonance revealed an 18-mm tumor ventral to the foramen magnum that significantly enlarged over the past 6 months. She underwent total tumor resection but then presented with progressive HC both clinically (i.e., instability of gait with confusion) and radiographically (computed tomography). Following placement of a lumboperitoneal (LP) shunt, symptoms markedly improved. Further, the cerebrospinal fluid (CSF) analysis showed elevated cell counts and protein concentrations, indicating likely "leakage" of intratumoral contents postoperatively contributing to the progressive HC. Conclusion: Patients presenting with acute meningiomas ventral to the foramen magnum may develop postoperative communicating HC attributed to tumor-related CSF leakage of necrotic intratumoral components that can be successfully treated with a LP shunt.

Ruthenibacterium lactatiformans isolated from a human blood culture: a first report.

BACKGROUND: Ruthenibacterium lactatiformans, a Gram-stain-negative, rod-shaped, obligate anaerobic bacterium of the Oscillospiraceae family, has not been previously reported in human infections. This study reports the first case of bacteraemia and potential vertebral osteomyelitis caused by Ruthenibacterium lactatiformans. CASE PRESENTATION: An 82-year-old man with a history of diabetes, chronic renal failure, and prior spinal surgery for spondylolisthesis and spinal stenosis presented with fever and lower back pain. Magnetic resonance imaging revealed multiple vertebral osteomyelitis lesions. Initial blood cultures identified methicillin-resistant Staphylococcus aureus (MRSA), which prompted vancomycin treatment. However, repeated blood cultures not only confirmed persistent MRSA, but also detected Gram-negative bacilli (GNB). Despite surgical removal of the spinal hardware and antimicrobial therapy, the patient's osteomyelitis worsened, necessitating transfer for further management. Subsequent analysis using 16S rRNA gene sequencing identified the GNB as Ruthenibacterium lactatiformans. CONCLUSIONS: This is the first documented instance of human infection with Ruthenibacterium lactatiformans, signifying its pathogenic potential in vertebral osteomyelitis. The involvement of anaerobic bacteria and the possibility of polymicrobial infections complicate the diagnosis and treatment of vertebral osteomyelitis. This report underscores the need for caution when identifying the causative organism and selecting an appropriate treatment.

Psoriasis vulgaris of the skin caused a L3-L4 lumbar epidural spinal abscess.

Background: In a 31-year-old male, psoriasis vulgaris (PV) of the skin caused paraparesis attributed to a L3-L4 epidural spinal abscess that required emergent surgical decompression. Case Description: A 31-year-old male presented with lower back pain and cauda equina compression attributed to a magnetic resonance-documented L34 enhancing lesion consistent with a spinal epidural abscess (SEA). The skin over the L3-L4 level revealed severe PV that proved to be the likely etiology of the right-sided paraspinal muscle abscess, infected right L3-L4 facet joint, and SEA. At surgery, the foci of infection were excised/decompressed, and cultures grew methicillin-susceptible Staphylococcus aureus. Following surgery, the patient was improved and was treated with appropriate antibiotic therapy. Conclusion: PV caused a L3-L4 epidural spinal abscess and cauda equina compression in a 31-year-old male who was successfully treated with operative decompression and appropriate antibiotic management.

Atlantoaxial Intradural Synovial Cyst Mimicking an Extradural Lesion Adjacent to a Retro-odontoid Pseudotumor: A Case Report.

Atlantoaxial synovial cysts can very rarely penetrate the dura mater into the thecal sac and cause direct neural compression. Several case reports have been available on "intradural synovial cysts" (IDSCs). In this study, we report on a case with an atlantoaxial IDSC mimicking an extradural lesion. A 90-year-old man was diagnosed with a cystic lesion located laterally to the atlantoaxial joint adjacent to the retro-odontoid pseudotumor (ROP) causing cervical spinal cord compression. Thus, surgical removal was planned. On preoperative examination, the cyst, which had a two-layer structure showing a T2-isointense small mass inside a T2-hyperintense lesion, was thought to be located in the extradural region. However, operative findings showed that the cyst was located inside the dura mater. Histopathological examination suggested a synovial cyst. No recurrence of the cyst was observed until the latest follow-up after 3 years, and the ROP decreased in size. Almost all IDSCs reported previously were observed in the medial site of the atlantoaxial joint. In our case, however, the cyst was observed adjacent to the posteromedial site of the right atlantoaxial joint and the ROP, mimicking an extradural lesion. We had no knowledge regarding the IDSC before the surgery and assumed an extradural lesion. Albeit rare, the existence of such a condition should be considered.

Lateral Lumbar Interbody Fusion Using Bone Graft Substitute for Lumbar Vertebral Fracture Associated Radiculopathy.

This study aims to present our surgical technique of lateral lumbar interbody fusion (LLIF) without corpectomy for lumbar vertebral fracture (LVF) associated radiculopathy. This study includes three patients treated with LLIF (mean age of 77.3 years, Group L) and three patients treated with PLIF (mean age of 75.7 years, Group P) to compare the surgical outcomes. The cartilage on the fractured vertebrae was aggressively resected with attention to avoid injury to the ring apophysis. The central cavity of the fractured endplate was filled with a bone graft substitute made of hydroxyapatite and collagen composite, followed by interbody fusion achieved by utilizing of a cage with sufficient length spanning the bilateral edges of the fractured vertebra. PLIF was performed with a standard technique using two interbody cages, and vertebroplasty was combined in one patient. Comparing to PLIF, LLIF could be performed with less estimated blood loss in shorter surgical time. Local kyphotic angle improved in all cases of Group L immediately after the surgery, but correction loss was observed at the final examination. The lordotic angle was lost in Group P postoperatively. Arthrodesis was achieved in all the cases. The mean VAS score for leg pain was 85.3 mm in Group L and 82.0 mm in Group P at preoperation and decreased to 8.7 mm and 11.3 mm, respectively, at postoperation. LLIF is an effective surgical option that enables stabilization of the fractured vertebra and reduces radicular pain by indirect neural decompression.

Diffuse Idiopathic Skeletal Hyperostosis with Severely Displaced Spine Fracture Managed with Posterior Approach Alone: Case Reports and Literature Review.

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition in which minor trauma can cause extremely unstable vertebral fractures. Spinal fractures associated with DISH are prone to instability due to the large moment of lever arm and secondary neurological deterioration; hence, surgical internal fixation is considered necessary. On the other hand, some reports suggest that patients with DISH have a high osteogenic potential. In this report, we describe three patients with DISH. These patients had spinal injuries that resulted in a large gap, for which anterior fixation with bone graft would generally be considered due to comminuted fractures. However, we achieved good bony fusion with posterior fixation alone, without forcible correction.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Isolation of human adult olfactory sphere cells as a cell source of neural progenitors.

Olfactory stem cells are generated from olfactory mucosa. Various culture conditions generate olfactory stem cells that differ according to species and developmental stage and have different progenitor or stem cell characteristics. Olfactory spheres (OSs) are clusters of progenitor or stem cells generated from olfactory mucosa in suspension culture. In this study, adult human OSs were generated and their characteristics analyzed. Human OSs were adequately produced from olfactory mucosa with area over 40 mm(2). Immunocytochemistry (ICC) and fluorescence-activated cell sorting showed that human OSs were AN2 and A2B5-positive. Immunofluorescence analysis of cell type-specific ICC indicated that the number of Tuj1-positive OS cells was significantly elevated. Tuj1-positive cells displayed typical neuronal soma and dendritic morphology. Human OS cells were also immunopositive for MAP2. By contrast, few RIP-, O4-, and GFAP-positive cells were present. These RIP, O4, and GFAP-positive cells did not resemble bona fide oligodendrocytes and astrocytes morphologically. In culture to induce differentiation of oligodendrocytes, human OS cells also expressed neuronal markers, but neither oligodendrocyte or astrocyte markers. These findings suggest that human OS cells autonomously differentiate into neurons in our culture condition and have potential to be used as a cell source of neural progenitors for their own regenerative grafts, avoiding the need for immunosuppression and ethical controversies.

Differences between Cervical Schwannomas of the Anterior and Posterior Nerve Roots in Relation to the Incidence of Postoperative Radicular Dysfunction.

STUDY DESIGN: A retrospective study. PURPOSE: To assess the case files of patients who underwent surgery for cervical dumbbell schwannoma for determining the differences between schwannomas of the anterior and posterior nerve roots with respect to the incidence of postoperative radicular dysfunction. OVERVIEW OF LITERATURE: The spinal roots giving origin to schwannoma are frequently nonfunctional, but there is a risk of postoperative neurological deficit once these roots are resected during surgery. METHODS: Fifteen patients with cervical dumbbell schwannomas were treated surgically. Ten men and 5 women, who were 35-79 years old (mean age, 61.5 years), presented with neck pain (n=6), radiculopathy (n=10), and myelopathy (n=11). RESULTS: Fourteen patients underwent gross total resection and exhibited no recurrence. Follow-ups were performed for a period of 6-66 months (mean, 28 months). Preoperative symptoms resolved in 11 patients (73.3%) but they persisted partially in 4 patients (26.7%). Six patients had tumors of anterior nerve root origin, and 9 patients had tumors of posterior nerve root origin. Two patients who underwent total resection of anterior nerve root tumors (33.3%) displayed minor postoperative motor weakness. One patient who underwent total resection of a posterior nerve root tumor (11.1%) showed postoperative numbness. CONCLUSIONS: Appropriate tumor removal improved the neurological symptoms. In this study, the incidence of radicular dysfunction was higher in patients who underwent resection of anterior nerve root tumors than in patients who underwent resection of posterior nerve root tumors.

Intranasal delivery of bone marrow stromal cells to spinal cord lesions.

OBJECT: The intranasal delivery of bone marrow stromal cells (BMSCs) or mesenchymal stem cells to the injured brains of rodents has been previously reported. In this study, the authors investigated whether BMSCs migrate to spinal cord lesions through an intranasal route and whether the administration affected functional recovery. METHODS: Forty Sprague-Dawley rats that were subjected to spinal cord injuries at the T7-8 level were divided into 5 groups (injured + intranasal BMSC-treated group, injured + intrathecal BMSC-treated group, injured-only group, injured + intranasal vehicle-treated group, and injured + intrathecal vehicle-treated group). The Basso-Beattie-Bresnahan (BBB) scale was used to assess hind limb motor functional recovery for 2 or 4 weeks. Intralesionally migrated BMSCs were examined histologically and counted at 2 and 4 weeks. To evaluate the neuroprotective and trophic effects of BMSCs, the relative volume of the lesion cavity was measured at 4 weeks. In addition, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels in the CSF were evaluated at 2 weeks. RESULTS: Intranasally administered BMSCs were confirmed within spinal cord sections at both 2 and 4 weeks. The highest number, which was detected in the intrathecal BMSC-treated group at 2 weeks, was significantly higher than that in all the other groups. The BBB score of the intranasal BMSC-treated group showed statistically significant improvements by 1 week compared with the control group. However, in the final BBB scores, there was a statistically significant difference only between the intrathecal BMSC-treated group and the control group. The cavity ratios in the BMSC-treated groups were smaller than those of the control groups, but the authors did not find any significant differences in the NGF and BDNF levels in the CSF among the treatment and control groups. CONCLUSIONS: BMSCs reached the injured spinal cord through the intranasal route and contributed to the recovery of hind limb motor function and lesion cavity reduction. However, the effects were not as significant as those seen in the intrathecal BMSC-treated group.

Retro-odontoid synovial cyst resected via an anterolateral approach without fusion.

PURPOSE: Retro-odontoid synovial cysts are rare and attributable to degenerative changes in the atlantoaxial joints. An anterolateral approach facilitates access to lesions located anterior to the craniocervical junction without harming the atlantoaxial joints, and can also treat small lesions in the ventral mid-portion of the craniocervical junction without compression of spinal cord. METHODS: We present herein the case of a 70-year-old man with a retro-odontoid synovial cyst. A ventral midsection mass was present at the level of the atlantoaxial joint. The compressed anterior medulla led to neurological deficits. Slight atlantoaxial instability was radiologically present. An intradural cyst resection without fusion was performed via the anterolateral approach. The diagnosis of a synovial cyst was histologically confirmed. RESULTS: The patient was followed up for 3 years and exhibited improvements in the neurological deficits. There were no recurrence and postoperative deterioration of atlantoaxial instability. CONCLUSIONS: The anterolateral approach for the retro-odontoid synovial cyst had little effect on C1-2 instability and yielded neurological improvements.

Adjacent lumbar disc herniation after lumbar short spinal fusion.

A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3-5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI) showed a large L2/3 disc hernia descending to the L3/4 level. Compared to the initial MRI, this hernia occurred in an "intact" disc among multilevel severely degenerated discs. Right leg paresis and bladder dysfunction appeared a few days after admission. Microscopic lumbar disc herniotomy was performed. The right leg motor weakness improved just after the operation, but the moderate left leg motor weakness and difficulty in urination persisted.

Syringomyelia associated with spinal arachnoiditis treated by partial arachnoid dissection and syrinx-far distal subarachnoid shunt.

The authors describe a new modified surgical approach to minimize the postoperative recurrence of a syrinx after surgery to treat syringomyelia associated with spinal adhesive arachnoiditis in two cases. Both patients presented with progressive gait disturbance without any remarkable history, and spinal magnetic resonance imaging revealed a syrinx and broad irregular disappearance of the subarachnoid space and/or deformity of the cord. We successfully performed a partial arachnoid dissection and syrinx-far distal subarachnoid shunt for both cases.

Presence of trans-synaptic neurons derived from olfactory mucosa transplanted after spinal cord injury.

STUDY DESIGN: Using biotinylated dextran amine (BDA) and wheat germ agglutinin (WGA) tracers, we measured the effectiveness of olfactory mucosa (OM) transplantation as a scaffold in a rat model of chronic spinal cord injury (SCI). OBJECTIVE: We examined whether OM transplantation for chronic SCI in rats results in reconstruction of neuronal pathways by both regeneration of the remaining axons and supply of OM-derived trans-synaptic neurons. SUMMARY OF BACKGROUND DATA: OM is one of the ideal scaffolds for axonal regeneration after chronic SCI. METHODS: Rats received a mild contusion at vertebral level T6-T7. Two weeks after SCI, enhanced green fluorescent protein rat-derived OM, respiratory mucosa, and phosphate-buffered saline were transplanted into each group of SCI rats. Ten weeks after SCI, BDA was injected into the right sensorimotor cortex. Eleven weeks after SCI, WGA was injected into the L1-L2 posterior column to label the corticospinal tract retrogradely and trans-synaptically. Twelve weeks after SCI, rats were killed and their spinal cords were divided into cervical (area a), thoracic-injured (area b), and lower thoracic portions (area c). Immunohistochemically, sections of area (b) were evaluated by counting cells positive for enhanced green fluorescent protein, 4',6-diamidino-2-phenylindole, WGA, and BDA (OM and respiratory mucosa groups). Axonal regenerations were estimated by counting WGA- and BDA-positive dots in transverse sections of area (a) and area (c). RESULTS: Compared with respiratory mucosa and phosphate-buffered saline transplantation, OM transplantation increased the number of WGA-positive dots in area (a), and the number of BDA-positive dots in area (c) was more after OM transplantation than after phosphate-buffered saline transplantation. Furthermore, the number of quadruple-positive cells in area (b) was much higher after OM transplantation. CONCLUSION: Our results provide both indirect and direct evidence for the presence of trans-synaptic neurons. OM transplantation in rats with chronic SCI resulted in reconstruction of neural pathways by both providing trans-synaptic neurons and supporting regeneration of remaining axons. The olfactory mucosa is thought to be an efficacious scaffold to produce the relay neuron in chronic spinal cord injury.