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Tetsuya Tamaki

Publications and source records attributed to Tetsuya Tamaki.

14 recordsLinked to original sources
PubMed2003

A clinical case of endoscopically assisted anterior screw fixation for the type II odontoid fracture.

STUDY DESIGN: A clinical case using a new surgical technique is reported. OBJECTIVE: To report for the first time an endoscopically assisted anterior screw fixation for the Type II odontoid fracture. SUMMARY OF BACKGROUND DATA: Recently, many endoscopically assisted surgeries have been performed for various spinal surgery because of its minimally invasive character. However, the anterior retropharyngeal approach to the upper cervical spine using endoscopy has not been reported. METHODS: A 76-year-old man was operatively managed for a Type II odontoid fracture. The operation was performed under immobilization of cervical spine using a halo vest apparatus. A skin incision 2 cm long was made on the medial border of the right sternocleidomastoid muscle at the C5-C6 intervertebral level. Blunt dissection between the neurovascular bundle laterally and the trachea and esophagus medially was performed. A processed polyethylene syringe (volume, 10 mL) was used as the tubular retractor. This retractor kept the minimum but sufficient space for the screw fixation and avoided esophageal complication. Using a cannulated screw system, a cancellous screw was inserted from the anteroinferior edge of the C2 vertebral body to the tip of the odontoid process. The drilling and the screwing process was monitored by a two-dimensional image intensifier. The entry point was monitored by endoscopy to avoid soft tissue involvement as well. RESULTS: The operation was completed without any soft tissue complications such as esophageal injury. The blood loss was 30 mL. The procedure resulted in nonunion, partially because of patient's old age or an entry point 2 mm above the anterior caudal margin of the C2 body retrospectively. CONCLUSIONS: Although the reported odontoid fracture ended in nonunion, the authors believe their modification of the approach using an endoscope made anterior screw fixation for the odontoid fracture safer and less invasive than the original anterior retropharyngeal approach.

Aged↗
PubMed2003

Comparison of neuropathic pain induced by the application of normal and mechanically compressed nucleus pulposus to lumbar nerve roots in the rat.

We studied whether applying nucleus pulposus tissue, obtained from tail intervertebral discs that had been subjected to chronic mechanical compression, to the lumbar nerve roots produces hyperalgesia, which is thought to be a pain-related behavior in the rat. An Ilizarov-type apparatus was used for immobilization and chronically applied compression of the rat tail for eight weeks. Three weeks after application of extracted nucleus pulposus tissue on the lumbar nerve roots, motor function, sensitivity to noxious mechanical stimuli was measured. Eight weeks after application of the apparatus, the instrumented vertebrae were resected and sections were stained with hematoxylin and eosin to evaluate degeneration of the intervertebral disc. Mechanical hyperalgesia observed in rats treated with the compressed nucleus pulposus tissue was greater and of longer duration than in the rats treated with normal and non-compressed discs. The nucleus pulposus in the instrumented vertebrae showed some histological degeneration. In conclusion, chronic mechanical compression of nucleus pulposus, which resulted in degeneration to some extent, enhanced mechanical hyperalgesia, which was induced by application of nucleus pulposus on the nerve root in the rat. Degenerative intervertebral discs might induce more significant pain than normal intervertebral discs.

Animals↗
PubMed2003

Relationships between the changes in compound muscle action potentials and selective injuries to the spinal cord and spinal nerve roots.

OBJECTIVE: Compound muscle action potentials (CMAPs) evoked by transcranial electrical stimulation have been widely introduced to monitor motor function during spinal surgery. They may reflect segmental injuries as well as injuries to motor-related tracts in the spinal cord. However, we have experience with some patients who developed postoperative segmental motor weakness without any potential changes during surgery. To evaluate the efficacy of this method, we used a cat model to observe the relationships between potential changes and selective injuries to the white and gray matters of the spinal cord and spinal nerve roots. METHODS: Ten CMAPs were obtained before and after injury to the spinal cord and spinal nerve roots in 20 cats. Changes in the amplitude, latency, and duration of CMAPs were analyzed. RESULTS: CMAPs decreased in amplitude significantly after the insult to the motor-related tracts in the spinal cord in all cats, while the potentials did not always change when the insult was restricted to a limited area in the anterior horn of the spinal cord or to the single spinal nerve root. CONCLUSIONS: CMAPs may not exactly reflect segmental injury, and careful attention should be paid to the interpretation of CMAPs.

Action Potentials↗
PubMed2003

Transdiscal L5-S1 screws for the fixation of isthmic spondylolisthesis: a biomechanical evaluation.

The current study is a biomechanical study using a cadaveric model of L5-S1 spondylolisthesis. The purpose of the current study was to compare, in a cadaveric model of simulated L5-S1 spondylolisthesis, the biomechanical stiffness of transdiscal fixation with traditional pedicle screw fixation, and transdiscal fixation with combined interbody/pedicle screw fixation. The surgical management of L5-S1 spondylolisthesis is a challenge because of the difficulties in achieving a reliable arthrodesis in the face of high mechanical forces. A method of lumbosacral fixation that has been used successfully in moderate grades of spondylolisthesis at our institution involves the use of transdiscal S1 pedicle screws. With this technique, S1 pedicle screws are placed through the S1 pedicle, through the superior endplate of S1, through the inferior endplate of L5, to terminate in the L5 body. Eighteen fresh human cadaveric (age 59-88 years) L5-S1 motion segments were obtained. The end of each intact motion segment was potted up to its midbody in a 10-cm-diameter polyvinylchloride end-cap using dental cement. The intact specimen was then biomechanically tested as follows: 1) axial compression (500 N), 2) flexion (10 Nm), 3) extension (10 Nm), 4) right lateral bending (10 Nm), and 5) left lateral bending (10 Nm). Stiffness values were calculated from the load-deflection curves obtained. Spondylolisthesis was then simulated by displacing L5 on S1 (% slip average = 41.3%) after performing a radical L5-S1 discectomy, L5 laminectomy, and bilateral L5-S1 facetectomies. The 18 motion segments were divided into two groups. Group I (n = 10) was biomechanically tested (as above) after pedicle screw fixation and again after replacing the S1 pedicle screws with transdiscal screws. Group II (n = 8) was biomechanically tested (as above) after combined interbody/pedicle screw fixation and again after fixation with transdiscal screws. Load-deflection curves were obtained each time, and stiffness values were calculated from the curves. Transdiscal fixation was 1.6-1.8 times stiffer than pedicle screw fixation (p < 0.05) in all loading modes tested. There were no differences in stiffness between transdiscal fixation and combined interbody/pedicle screw fixation. In a cadaveric model of simulated L5-S1 spondylolisthesis, transdiscal L5-S1 fixation produced a 1.6-1.8 times stiffer construct than traditional pedicle screw fixation. Further, the stiffness of the transdiscal fixation was equal to that of a combined interbody/pedicle screw fixation.

Aged↗
PubMed2002

Does reconstruction of posterior ligamentous complex with extensor musculature decrease axial symptoms after cervical laminoplasty?

STUDY DESIGN: The authors retrospectively determined the prevalence of neck and shoulder symptoms (axial symptoms) after expansive laminoplasty with reattachment of spinous process and extensor musculature in patients with cervical myelopathy. OBJECTIVES: To determine the prevalence of both preoperative and postoperative axial symptoms of expansive laminoplasty when they occur after expansive laminoplasty. SUMMARY OF BACKGROUND DATA: Several clinical reports have noted that laminoplasty for cervical myelopathy produces positive clinical outcomes. However, recent reports have pointed out that complications from laminoplasty, such as axial symptoms, may be severe enough to interfere with daily activities. METHODS: The authors used a modified spinous process-splitting laminoplasty, which involved reattaching the spinous process with extensor musculature after enlarging the spinal canal by use of the French window method. Postoperative axial symptoms were investigated in 173 of 214 patients (80.1%) who underwent expansive laminoplasty between January 1989 and December 1998. The patients included 121 men and 52 women, and their average age was 61.5 years. The presence or absence and grade of axial symptoms before and after laminoplasty were investigated. The severity and duration of complications were also recorded, along with differences between age, sex, spinal alignment, and cervical diseases. RESULTS: Neck and/or shoulder stiffness worsened in 15% of the patients and declined in 21%. Neck pain worsened in 10% of the patients and improved in 11%. Neck and/or shoulder stiffness worse than moderate was recognized in 14.4% of the patients. Neck pain worse than moderate was recognized in 5% of the patients. In the 137 patients who had no axial pain before surgery, only 13 patients experienced such symptoms after surgery, and in most cases these symptoms were minimal. In only 1 case, significant postoperative neck pain arose de novo as a result of this surgery. In 88 patients who had no neck and/or shoulder stiffness before surgery, only 16 patients experienced such symptoms after surgery, and in most cases these were minimal. A similar pattern held true for each of the other grades of preoperative axial symptoms. The recovery rate score (Japanese Orthopedic Association) was 47.5 +/- 32.3 in the patients whose axial symptoms were worse than moderate and 60 +/- 28.9 in patients whose axial symptoms were less than mild. This difference was significant (P < 0.05). CONCLUSION: Laminoplasty is an appropriate operation for cervical spondylotic myelopathy and did not, in this study, seem to have any significant influence on the development or resolution of axial symptoms.

Adult↗
PubMed2002

Lumbar sagittal balance influences the clinical outcome after decompression and posterolateral spinal fusion for degenerative lumbar spondylolisthesis.

STUDY DESIGN: This study was designed to assess both lumbar sagittal balance and clinical outcomes of decompression and posterolateral fusion for degenerative lumbar spondylolisthesis. As an index for the radiologic evaluation of sagittal alignment, the L1 axis S1 distance was used (i.e., the horizontal distance from the plumbline of the center in the L1 to the back corner of the S1). OBJECTIVE: To determine whether lumbar sagittal balance affected the clinical outcome after posterolateral fusion. SUMMARY OF BACKGROUND DATA: Little is known about whether the sagittal vertical axis influences clinical outcomes in cases of degenerative lumbar spondylolisthesis. METHODS: A retrospective review of 47 patients (15 men and 32 women), ranging in age from 41 to 79 years, was conducted. The mean follow-up period was 3.6 years. Relations among outcomes including the visual analog pain scale, recovery rate, L1 axis S1 distance, slippage, and lumbar lordosis were evaluated. RESULTS: Recovery rates were 44% and 62% in patients whose preoperative L1 axis S1 distance, respectively, was more than 35 mm (Group A, n = 16) and less than 35 mm (Group B, n = 31) (P < 0.05). Follow-up assessment found a positive correlation between only lordosis and recovery rate. Severe low back pain and lower recovery rate were observed in patients with in situ fusion in Group A (n = 9), as compared with patients with reduced slippage in Group A (n = 7) and patients in Group B. CONCLUSIONS: Both preoperative L1 axis S1 distance and lordosis at follow-up assessment affected surgical outcome. Reduction of slippage may improve clinical outcomes of posterolateral fusion for degenerative lumbar spondylolisthesis with an L1 axis S1 distance more than 35 mm.

Adult↗
PubMed2002

Discrepancy between decreases in the amplitude of compound muscle action potential and loss of motor function caused by ischemic and compressive insults to the spinal cord.

We examined the relationship between decreases in the amplitude of the compound muscle action potential (CMAP), caused by ischemic and compressive insults to the spinal cord, and postoperative motor deficits. Results were compared with those for other evoked potentials commonly used for multimodal monitoring of the spinal cord. CMAP was more sensitive than the other evoked potentials employed to ischemic and compressive insults to the spinal cord, although the disappearance of CMAP did not always result in a residual motor deficit. A decrease of more than 50% in the amplitude of the motor-evoked potential (MEP) from the spinal cord correlated well with the postoperative motor deficit. CMAP is a sensitive tool for the early detection of spinal cord impairment caused by ischemic or compressive insults to the spinal cord. The time after the disappearance of the CMAP amplitude was important for predicting postoperative motor deficit, but it is also necessary to employ CMAP concomitantly with other conductive potentials in spinal cord monitoring.

Action Potentials↗
PubMed2002

Epidural injection of cyclooxygenase-2 inhibitor attenuates pain-related behavior following application of nucleus pulposus to the nerve root in the rat.

Cyclooxygenase-2 (COX-2), the inducible isoform of COX, has been identified as the key enzyme to regulate prostaglandin E2 synthesis in inflammatory conditions. Although it has been reported that COX-2 is present in herniated disc samples obtained from patients, little is known concerning the relationships between COX-2 and painful radiculopathy. The purpose of this study was to evaluate whether epidural injection of COX-2 inhibitor abolishes hyperalgesia induced by nucleus pulposus, which is a pain-related behavior in the rat. Rats, in which nucleus pulposus was relocated on the nerve root, exhibited evidence of mechanical hyperalgesia. Epidural injection of COX-2 inhibitor resulted in decrease in mechanical hyperalgesia 1 h, 3 and 7 days after the epidural injection of COX-2 inhibitor (0.1 mg/kg SC-'236 dissolved in the vehicle). There were no significant differences in sensitivity to thermal noxious stimuli after either application of the nucleus pulposus or epidural injections. These results suggest that prostaglandins and thromboxane, which are produced by COX-2 in inflammatory cells, appear to be related to the inflammatory process produced by application of nucleus pulposus to the nerve root. It is possible that COX-2 plays a significant role in painful radiculopathy following herniated nucleus pulposus.

Animals↗
PubMed2002

Vascularized fibular osteocutaneous grafts in the treatment of severely infected wrist arthritis.

The authors successfully treated two cases of wrist arthritis severely infected by Staphylococcus aureus and Mycobacterium tuberculosis with vascularized fibular osteocutaneous grafts. The surgical procedure was divided into two stages, with extensive debridement of the infected wrist joint, and reconstruction with a vascularized fibular osteocutaneous flap. This two-staged surgery yielded complete amelioration of the severely infected wrist arthritis, and permanent stabilization of the wrist joint.

Arthritis, Infectious↗
PubMed2002

Preoperative instability does not influence the clinical outcome in patients with cervical spondylotic myelopathy treated with expansive laminoplasty.

Sixty-seven patients with cervical spondylotic myelopathy treated with expansive laminoplasty were retrospectively reviewed at a minimum 2-year follow-up. This study was designed to evaluate whether preoperative instability influences the clinical outcome in patients with cervical spondylotic myelopathy treated with laminoplasty without spinal fusion. Patients with preoperative instability were older and had shorter durations of symptoms prior to surgery than those without the instability. There were no significant differences in prevalence of axial symptoms, neurologic recovery, or radiologic findings between patients with and without preoperative cervical instability. At follow-up, the cervical range of motion was limited to 43.5% of the preoperative range, and no cervical instability was observed in any patients. Preoperative instability does not influence the clinical outcome and can be ignored if expansive laminoplasty is indicated for patients with cervical spondylotic myelopathy.

Adult↗
PubMed2002

Relationships between sagittal alignment of the cervical spine and morphology of the spinal cord and clinical outcomes in patients with cervical spondylotic myelopathy treated with expansive laminoplasty.

A total of 103 patients with cervical spondylotic myelopathy undergoing laminoplasty were retrospectively reviewed to evaluate whether sagittal alignment of the cervical spine and morphology of the spinal cord influence surgical outcomes. Sagittal alignment of the cervical spine did not influence surgical outcomes. Neurologic recovery in patients with anterior convexity of the spinal cord was better than in those without this type of spinal cord. In patients with supplementation of decompression at C2, sagittal morphology of the spinal cord did not influence neurologic recovery. It is important to acquire anterior convexity of the spinal cord after surgery if laminoplasty is performed below C3. In patients with kyphosis, where anterior convexity of the spinal cord is not thought to be obtained postoperatively, it is possible that additional decompression of C2 improves outcome.

Adult↗
PubMed2002

Incidentally diagnosed Kienböck's disease.

The results of examinations of 14 patients with incidentally diagnosed Kienböck's disease were reviewed. These patients had not been examined previously, clinically or radiographically, and had not received any treatment for their condition. For 12 of these patients, Kienböck's disease was diagnosed incidentally on radiographic examinations obtained for other reasons, including carpal tunnel syndrome in four patients, Colles' fracture in three patients, pseudogout attack in the wrist in two patients, infection of the hand in one patient, osteoarthritis of the carpometacarpal joint of the thumb in one patient, and osteoarthritis of the metacarpophalangeal joint in one patient. The remaining two patients were diagnosed incidentally with Kienböck's disease based on radiographs obtained from a medical examination. Although radiographic findings revealed an advanced Kienböck's disease, current symptoms were mild in all patients, no problems with wrist pain were observed in activities of daily living or at work, and no treatment for Kienböck's disease was required. Appropriate treatment for Kienböck's disease should be considered carefully because some patients have no problems with activities of daily living or work for many years.

Aged↗
PubMed1999

Plastic changes in sensory inputs to rat substantia gelatinosa neurons following peripheral inflammation.

Although hyperalgesia elicited by inflammation has been shown to be partly due to central sensitization, the cellular mechanisms are not clear at the moment. The present study was designed to address this issue using the blind whole-cell patch-clamp technique; glutamatergic primary-afferent inputs to substantia gelatinosa (SG) neurons were compared between spinal cord slices of naive rats and rats inflamed by an intraplantar injection of complete Freund's adjuvant. In naive rats, a large number of SG neurons examined received monosynaptic A delta- (69% of 41 neurons innervated by A fibers) and/or polysynaptic C- (94% of 36 neurons innervated by C fibers) afferent inputs, and only a few neurons received monosynaptic A beta inputs (7%). In addition, when examined in neurons which have both of the A- and C-afferent inputs, A afferent-evoked excitatory postsynaptic currents (EPSCs) were larger in amplitude than C afferent-induced ones; a ratio (A/C ratio) of the former to latter amplitude was 1.8 +/- 0.1 (n = 36). In inflamed rats, a change in the synaptic responses was observed: (1) SG neurons receiving monosynaptic A delta-afferent inputs decreased in number (to 20% of 30 neurons tested, innervated by A fibers), whereas those having monosynaptic A beta-afferent inputs increased to 33%, and (2) the A/C ratio decreased to 0.7 +/- 0.1 (n = 33). These results suggest that after inflammation, a substantial number of A beta-afferents sprout into the SG from their original location (laminae III-V) and that sensory information that used to be conveyed directly to the SG through A delta afferents is transmitted there indirectly through interneurons. These reorganizations of sensory pathway may contribute, at least in part, to underlying mechanisms for the development of hyperalgesia due to inflammation.

Animals↗