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K Nibu

Publications and source records attributed to K Nibu.

At least 37 records · Page 2Linked to original sources
PubMed1998

Head kinematics during in vitro whiplash simulation.

Knowledge of precise head kinematics during whiplash trauma is important for identifying possible injury mechanisms and their prevention. This study reports a comprehensive data set describing head kinematic response to horizontal accelerations simulating whiplash. Seven isolated fresh human cervical spine specimens (C0 to T1 or C7), each carrying a surrogate head designed to represent a 50th percentile human head, were mounted on the sled and subjected to incremental trauma by horizontal sled accelerations of 2.5, 4.5, 6.5, 8.5, and 10.5 g. Sled and head kinematics were measured with potentiometers and accelerometers. The incremental sled accelerations resulted in average (standard deviations) sled velocity changes (delta V) ranging from 5.8 (0.2) to 15.8 (0.2) km/h. Generally, all the peak head kinematic parameters increased with increasing sled acceleration, except for the peak head angular displacement, which decreased. In the initial phase of a whiplash trauma, the head translated posteriorly with respect to T1, without rotation. In the later phase, the head rotated backwards, but much less than its physiological limit. Maximum head rotation of 31.5 (23.9) degrees occurred in a 2.5 g trauma class, and this was less than the maximum physiological head extension of 55.1 (13.3) degrees. Head kinematics expressed in the T1 or shoulder coordinate system is better suited to study potential neck injury in whiplash.

Accidents, Traffic↗
PubMed1998

Immediate free flap reconstruction for head and neck pediatric malignancies.

We performed six immediate free flap reconstructions after tumor ablation in 5 children under the age of 15 years presenting with head and neck malignancy. One patient underwent free flap transfer on two separate occasions because of tumor recurrence. There were no flap losses nor were there any complications related to microvascular surgery. Although a pediatric head and neck malignant tumor is rare, surgical resection is the primary therapeutic role for those that are amenable to complete excision. Pediatric microsurgery provides a safe and reliable procedure for reconstruction of head and neck defects after extirpation of the tumor.

Adolescent↗
PubMed1998

Complications of craniofacial surgery for tumors involving the anterior cranial base.

OBJECTIVE: To evaluate the risk factors for postoperative complications among patients undergoing craniofacial resection for the treatment of anterior cranial base tumors, a retrospective analysis of patients treated in University of Tokyo Hospital between September 1987 and November 1996 was conducted. METHODS: Twenty-nine patients underwent 33 craniofacial resections for tumors involving the anterior cranial base. Twenty-three of the 29 patients had malignant tumors and 6 patients had benign tumors. Anterior craniofacial resection was performed using a combination of intracranial and extracranial approaches. Radiotherapy and neoadjuvant chemotherapy were administrated to some patients. RESULTS: Severe intracranial infections were more common among patients who underwent partial frontal lobectomies (P < 0.03). These infections occurred only in patients who had been treated previously with a craniotomy (P < 0.02) and a total radiation dose of > or =60 Gy (P = 0.06). Neither management of the extracranial structures nor methods of reconstruction of the cranial base showed significant correlation with major postoperative complications. CONCLUSION: Compared with previous reports, craniofacial resection has become a relatively safe and effective procedure for the treatment of tumors involving the anterior cranial base. However, additional care should be taken with patients who have experienced a previous craniotomy, frontal lobe involvement, or radiotherapy with a total dose of > or =60 Gy.

Adolescent↗
PubMed1998

Keratinocyte growth factor and its receptor messenger RNA expression in nasal mucosa and nasal polyps.

To examine the potential biologic role of fibroblast growth factors (FGFs) in nasal polyps and nasal mucosa during chronic inflammatory conditions, we investigated messenger RNA (mRNA) expression of three members of the FGF family -- acidic FGF, basic FGF, and keratinocyte growth factor (KGF)-- in nasal polyp tissues, as well as in hyperplastic nasal mucosa. Using the sensitive method reverse transcription-polymerase chain reaction (RT-PCR), we demonstrated that of the examined FGFs, KGF had the most abundant mRNA expression in nasal polyps and nasal mucosa. We also found that significantly higher levels of KGF mRNA were expressed in nasal polyps than in nasal mucosa, whereas mRNA expression of acidic FGF and basic FGF was relatively low in these tissues. In addition, we showed that KGF receptor mRNA was present in most of the nasal mucosa; however, none or little was expressed in nasal polyps. These results suggest that KGF might play an important role in nasal epithelial proliferation and that excessive synthesis of KGF in nasal polyp stroma may contribute to hypertrophy of the nasal mucosa in patients with chronic sinusitis associated with nasal polyposis.

Adult↗
PubMed1998

Biomechanical study of lumbar spinal stability after osteoplastic laminectomy.

The biomechanical stability of the lumbar spine after two surgical procedures of total facetectomy and osteoplastic laminectomy was investigated using fresh-frozen human cadaveric lumbar spine specimens. Six pure moments in flexion-extension, right-left bending, and right-left twisting were applied and intervertebral motions were recorded using an optoelectronic motion measurement system. Neutral zone (NZ) and range of motion (ROM) under three conditions of intact, total facetectomy, and osteoplastic laminectomy were analyzed statistically to determine comparative biomechanical potential for instability. Results of NZ showed no changes in any direction with respect to the intact behavior after the two procedures. Also, in lateral bending, there were no significant increases in ROM after the two procedures. However, flexion-extension ROM increased significantly (+33%, p < 0.05) after the total facetectomy, but not after osteoplastic laminectomy. Axial rotation ROM increased remarkably after the total facetectomy (+113%, p < 0.05), but only moderately (+57%, p < 0.05) after the osteoplastic laminectomy. The osteoplastic laminectomy, which preserves the spinous process as well as the facet joints, maintains greater spinal stability than the total facetectomy.

Aged↗
PubMed1998

Capsular ligament stretches during in vitro whiplash simulations.

Clinical symptoms of whiplash are presently not well understood. Injuries to capsular and other spinal ligaments of the cervical spine during trauma are a possible pathomechanism that could explain some aspects of the whiplash symptom complex. This study quantified the elongations of capsular ligaments (CLs) at all cervical spinal levels during whiplash simulation using an in vitro model. Seven fresh human cadaveric specimens (occiput-C7 or T1) were carefully dissected, preserving the osteoligamentous structures. Spinal ligament transducers were attached across the CLs from C2-C3 to C6-C7 in each specimen, alternating the two sides. Physiological elongations of the CLs were measured with a standard flexibility test using 1 Nm of pure moments. Next, the specimen was fitted with a surrogate head representing 50th percentile human head. The specimen was mounted on a sled designed to simulate whiplash and subjected to 2.5, 4.5, 6.5, 8.5, and 10.5 g (1 g = 9.81 m/s2) horizontal accelerations sequentially. The dynamic elongations of the CLs were continuously recorded during the entire trauma and were later converted to strains. There were modest increases in capsular ligament strains during the trauma over the maximum physiological values. The two largest peak strains of 29.5 and 35.4% were seen at C6-C7 during the 6.5- and 10.5-g accelerations. We did not find strong correlation between the strain during the trauma and the trauma sled acceleration.

Acceleration↗
PubMed1997

Whiplash produces an S-shaped curvature of the neck with hyperextension at lower levels.

STUDY DESIGN: A bench-top trauma sled was used to apply four intensities of whiplash trauma to human cadaveric cervical spine specimens and to measure resulting intervertebral rotations using high-speed cinematography. OBJECTIVES: To determine the cervical spine levels most prone to injury from whiplash trauma and to hypothesize a mechanism for such injury. SUMMARY OF BACKGROUND DATA: Whiplash injuries traditionally have been ascribed to hyperextension of the head, but other mechanisms such as hypertranslation also have been suggested. METHODS: Six occiput to T1 (or C7) fresh cadaveric human spines were studied. Physiologic flexion and extension motions were recorded with an Optotrak motion analysis system by loading up to 1.0 Nm. Specimens then were secured in a trauma sled, and a surrogate head was attached. Flags fixed to the head and individual vertebrae were monitored with high-speed cinematography (500 frames/sec). Data were collected for 12 traumas in four classes defined by the maximum sled acceleration. The trauma classes were 2.5 g, 4.5 g, 6.5 g, and 8.5 g. Significance was defined at P < 0.01. RESULTS: In the whiplash traumas, the peak intervertebral rotations of C6-C7 and C7-T1 significantly exceeded the maximum physiologic extension for all trauma classes studied. The maximum extension of these lower levels occurred significantly before full neck extension. In fact, the upper cervical levels were consistently in flexion at the time of maximum lower level extension. CONCLUSIONS: In whiplash, the neck forms an S-shaped curvature, with lower level hyperextension and upper level flexion. This was identified as the injury stage for the lower cervical levels. A subsequent C-shaped curvature with extension of the entire cervical spine produced less lower level extension.

Biomechanical Phenomena↗
PubMed1997

Transforaminal and posterior decompressions of the lumbar spine. A comparative study of stability and intervertebral foramen area.

STUDY DESIGN: Ten fresh, cadaveric, two-vertebrae, functional spinal units were used to study the pathoanatomy, intervertebral foraminal area, and flexibility changes after posterior and transforaminal decompression. OBJECTIVES: To determine the feasibility of an endoscopic transforaminal approach as an alternative to conventional approaches, to establish the adequacy of transforaminal decompression without destabilizing the spine, and to study the structural changes in the spine after decompressions. SUMMARY OF THE BACKGROUND DATA: Posterior decompression entails major dissection and excision of bone and ligaments to access the spinal canal. Posterior decompression may be complicated by acute or chronic spinal instability, and the adequacy of lateral decompression is highly subjective. METHODS: The functional spinal units were mounted in quick-setting epoxy blocks. Pre- and postoperative computed tomography scans were taken to study changes in the foraminal area. Pre- and postoperative flexibility and anatomic studies were performed to compare the results. RESULTS: A 45.5% increase in the intervertebral foraminal area was possible, there was no flexibility change, and minimal anatomic damage to the spine was noted after transforaminal decompression. A 34.2% increase in the intervertebral foraminal area and a significant increase in extension and axial rotation flexibility were noted after the posterior decompression. CONCLUSION: Transforaminal decompression produced a significantly larger increase in the intervertebral foraminal area than posterior decompression, without increasing the range of motion or neutral zone in any direction. Because there was no violation of the anatomic integrity of the spine in the transforaminal approach, the risk of surgically induced instability was minimized. Endoscopic transforaminal decompression is a feasible alternative to current approaches.

Adult↗
PubMed1997

Nerve paralysis after surgery in the submandibular triangle: review of University of Tokyo Hospital experience.

BACKGROUND: We assessed the incidence of neural complications in submandibular surgery in relation to the type of surgery, experience of the surgeon, and other factors. METHODS: We retrospectively reviewed the records of 133 patients who underwent excision of the submandibular triangle components at the University of Tokyo Hospital during the last 19 years. RESULTS: The most frequent complication was mandibular branch paralysis. Excluding 12 patients with malignant tumors, facial weakness was present postoperatively in 29.8% (37) or 124 resections. All palsies subsequently resolved. The paralysis was more frequent when nerve identification was performed than when it was not. CONCLUSIONS: The cardinal factors in minimizing incidence of nerve damage are an understanding of the anatomy of the nerves, low and generous skin incision, awareness of orientation in the surgical planes, avoidance of the use of metal retractors, and avoidance of elaborate identification of the nerve.

Adolescent↗
PubMed1997

Partial laryngectomy in the treatment of radiation-failure of early glottic carcinoma.

BACKGROUND: This study was undertaken to analyze the functional results, complications, local control rates, and survival in patients undergoing conservation surgery for squamous cell carcinoma (SCC) of the larynx as a salvage procedure for recurrent tumors after previous radiotherapy. METHODS: Twenty-one patients underwent frontolateral laryngectomy for radiation failure, T1 and T2 glottic SCC, at the Cancer Institute Hospital, Tokyo, from 1976 to 1991. All patients were men between the ages of 42 and 83 years. The disease-free interval ranged from 1 to 87 months (median, 26 months). The stage at initial treatment was T1 in 17 patients and T2 in four patients. Local recurrence developed in three patients. RESULTS: The rate of local control was influenced by a surgical margin of less than 1 mm (p < 0.05). Overall voice preservation was achieved in 86% of the patients. The 5-year and 10-year survival rates following frontolateral laryngectomy were 86% and 70%, respectively. Maximum phonation time after surgery ranged from 4 to 18 seconds (median, 8.1 seconds). CONCLUSIONS: These results indicate that in carefully selected cases, frontolateral laryngectomy may be used for treating radiation failure stage I or II vocal cord carcinomas with good success. Careful follow-up may be necessary in patients with a close surgical margin.

Adult↗
PubMed1997

Dynamic elongation of the vertebral artery during an in vitro whiplash simulation.

Clinical signs of whiplash are presently not well understood. Vertebral artery (VA) stretch during trauma is a possible pathomechanism that could explain some aspects of the whiplash symptom complex. This study quantified the VA elongation during whiplash simulation using an in vitro model. Seven fresh human cadaveric specimens (occiput to C7 or T1) were carefully dissected, preserving the osteoligamentous structures. The right VA was replaced with a thin nylon-coated flexible cable. This cable was fixed at one end to the occipital bone and at the other end to a specially designed VA transducer. Physiological motion of the occiput and physiological elongation of the VA were measured with a standard flexibility test. Next the specimen was mounted on a specially designed sled and subjected to 2.5, 4.5, 6.5, and 8.5 g (1 g = 9.81 m/s2) horizontal accelerations. Elongation of the VA was continuously recorded from the start of the trauma. The average (standard deviation) physiological VA elongation was 5.8 (1.6) mm in left lateral bending and 4.7 (1.8) mm in left axial rotation. Flexion and extension did not result in any appreciable elongation of the VA. The maximum VA elongation during the whiplash trauma significantly correlated with the horizontal acceleration of the sled (R2 = 0.7, P < 0.05). The VA exceeded its physiological range by 1.0 (2.1), 3.1 (2.6), 8.9 (1.6), and 9.0 (5.9) mm in the 2.5-, 4.5-, 6.5-, and 8.5-g trauma classes respectively.

Biomechanical Phenomena↗
PubMed1997

Spinal ligament transducer based on a hall effect sensor.

A spinal ligament transducer (SLT) was developed to measure in situ spinal ligament elongation during the simulation of whiplash trauma with a cadaveric spine specimen. The SLT was designed to be affixed to two K-wires drilled into the bone at the approximate points of ligament origin and insertion. The transducer is low cost and is capable of measuring the linear distance between the K-wires in the range 4-12 mm with the root mean square (RMS) accuracy of 0.025 mm.

Bone Wires↗
PubMed1997

The significance of arytenoid edema following radiotherapy of laryngeal carcinoma with respect to residual and recurrent tumour.

We sometimes experience patients with persistent or progressive arytenoid edema, among which residual or recurrent cancer is often accompanied. Because it is difficult to distinguish tumour rest or recurrence from normal tissue sequelae in the early period after irradiation, it is important to know both the contributing factors for arytenoid edema, and the incidence of residual or recurrent tumours in patients with postirradiation laryngeal edema. We therefore reviewed the charts of 67 patients with early laryngeal carcinoma who had received a curative dose of irradiation in the last 5 years. Fourteen patients (20.9%) had moderate or severe laryngeal edema persisting for or developing at more than 3 months after completion of a course of definitive radiotherapy. The incidence was highest in supraglottic T2 disease, followed by glottic T2 tumour. Of the 14 patients with edema, six (42.9%) had persistent or recurrent disease. The primary disease was uncontrolled in 18 patients, 17 of whom received successful salvage surgery. In patients without residual tumours, the edema was usually moderate and resolved within a year, although four patients had chronic edema lasting more than a year after treatment. All four had supraglottic T2 lesions and received 70 Gy of X-ray. We also reviewed, for sake of comparison, the records of 38 patients treated with radiotherapy at doses of more than 40 Gy between 1975 and 1980, when endoscopic microsurgery for laryngeal cancer was introduced as a primary part of treatment. The incidence of persistent or late developed edema over the period, though not significant, was 36.8%: nearly twice that of the last 5 years. Microscopic endolaryngeal surgical procedures seem to have been a causal factor for edema in this period.

Adult↗
PubMed1997

Anterior skull base surgery for secondary malignancies in retinoblastoma survivors: report of two cases.

With the improved survival rate of patients with retinoblastoma, the incidence of second malignancies has become substantial. We had two retinoblastoma survivors with secondary malignancies in the naso-ethmoidal complex, one a 21-year-old man with anaplastic carcinoma and the other a 16-year-old girl with malignant fibrous histiocytoma. They underwent repeated craniofacial surgery. Secondary malignancies arising at the nose and ethmoidal cells often invade the anterior skull base. The introduction of skull base surgery has provided wider surgical margins and increased the resultant likelihood of cure. Both patients have so far shown no evidence of recurrence.

Case Reports↗
PubMed1997

Stroboscopic observation of the larynx after radiation in patients with T1 glottic carcinoma.

We studied laryngeal video stroboscopy (LVS) system for evaluation of patients with glottic carcinoma (T1N0M0) before and after radiotherapy. There were 10 patients with T1 glottic squamous cell carcinoma (9 men and 1 woman) who received radiotherapy at the Hitachi General Hospital. We performed LVS before and after radiotherapy. The presence or absence of mucosal waves (MW) was particularly noted. No MW were present before radiotherapy but at 1-6 months after, MW gradually appeared. One year after radiotherapy all patients showed MW on LVS. In patients with glottic carcinoma MW recovered after radiation therapy. LVS may be useful for the clinical follow-up of post-radiation patients for early detection of recurrence of glottic carcinoma.

Carcinoma, Squamous Cell↗
PubMed1997

Multidirectional stabilizing potential of BAK interbody spinal fusion system for anterior surgery.

Improvement in laparoscopic surgery requires spinal-fusion devices appropriately designed for this technique. The BAK interbody fusion device (Spine Tech Inc., Minneapolis, MN, U.S.A.), which consists of two titanium screw cages, meets this requirement. Multidirectional stabilizing potential of this device was investigated by using an in vitro human cadaveric model. Four fresh-frozen human lumbosacral spine specimens (L5-S1) were used. The flexibility test consisted of applying six pure moments (flexion, extension, bilateral axial torques, and lateral bending moments) and measuring the ensuing three-dimensional motion. Moments were applied in four load steps: 0, 2.5, 5.0, 7.5, and 10.0 Nm, and for three load and unload cycles. Motion of the top vertebra was recorded during the third load cycle by using a three-dimensional optoelectronic motion-measurement system. The motion parameters studied were the ranges of motion (ROM) and the neutral zone (NZ). Comparing the ROM of the intact specimen and after the fixation, all motions except extension were reduced significantly (p < 0.005). Average percentage decrease in ROM were 45.8% in flexion, 40.4% in axial rotation, and 65.6% in lateral bending. The only significant changes in NZ were a 255.7% increase in extension, a 90.9% increase in axial rotation, and a 70.8% decrease in lateral bending. This biomechanical study revealed that the BAK system provided decreases in ROM in all directions except in extension. The increased NZ in extension and axial rotation is most likely related to the positioning of the implant. Because these implants were placed from the anterior, damage to anterior annulus and anterior longitudinal ligament is inevitable. For clinical relevance, the patients undergoing this surgical procedure should avoid extension motions.

Adult↗
PubMed1996

[A case of middle cranial fossa meningioma extending into the infratemporal fossa: an approach to the pterygoid extension of the sphenoid sinus via the infratemporal fossa].

A case of middle cranial fossa meningioma extending into infratemporal fossa and the pterygoid process is presented. The patient had a sphenoid sinus extending inferolaterally into the pterygoid process, which is known as pterygoid extension of the sphenoid sinus. This type of variation of the sphenoid sinus allowed a safe and well-oriented approach to the pterygoid process via the infratemporal fossa. The tumor extending into the pterygoid process was removed successfully without damaging any surrounding structures, e.g. maxillary nerve or Vidian nerve. However, pterygoid extension of the sinus is seen in only 40% of cases. Therefore, close preoperative examination with bone window CT scan is mandatory before employing this approach.

Cranial Fossa, Posterior↗