Eiki Nomura

Long-term Follow-up and Knee Osteoarthritis Change After Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation

Background Proximal or distal realignment procedures have long been selected as treatment for recurrent patellar dislocation, but associated knee osteoarthritis has been a substantial problem that leads to poor results. A new approach, medial patellofemoral ligament reconstruction, has recently started, but there have been no reports on the long-term follow-up. Hypothesis Anatomical medial patellofemoral ligament reconstruction can lead to satisfactory long-term outcome and a low association rate of knee osteoarthritis. Study Design Case series; Level of evidence, 4. Methods Twenty-four knees from 22 patients who underwent medial patellofemoral ligament reconstruction for recurrent patellar dislocation were reviewed at a mean follow-up of 11.9 years (range, 8.5-17.2 years). A lateral release was done on 14 of 24 knees. The clinical/physical outcome and the association of knee osteoarthritis were investigated. Patellofemoral and femorotibial osteoarthritis on the radiographs was evaluated using the Crosby/Insall and the Kellgren/Lawrence grading systems. Results According to the Crosby/Insall criteria, 11 knees (46%) were classified as excellent, 10 (42%) as good, 3 (12%) as fair/poor, and none as worse at follow-up. Further lateral subluxation or dislocation occurred in only 2 knees. The mean Kujala score improved significantly from 63.2 points preoperatively to 94.2 points at follow-up (P < .0001). According to the Crosby/Insall grading system, patellofemoral osteoarthritis was none to mild in 23 of the 24 knees and moderate in 1 knee, preoperatively. At the final follow-up, 21 knees were none to mild, and 3 knees were moderate. There were only 2 knees that had definite progression from none to mild to a moderate grade. Conclusion The association of definite knee osteoarthritis in medial patellofemoral ligament reconstruction with or without lateral release was small in the long-term follow-up. The conclusion is that medial patellofemoral ligament reconstruction not only prevents further patellar dislocation but also shows no or only slight progression of knee osteoarthritis.

An algorithm guiding the evaluation and treatment of acute primary patellar dislocations.

Primary patellar dislocation continues to be a common problem facing clinicians today. These injuries are associated with significant morbidity and a substantial recurrence rate. A myriad of operative and nonoperative options have been described to treat these injuries though the evidence-based literature is sparse. As a result, much controversy exists regarding the ideal management of the primary patellar dislocation. This article reviews the literature on this topic, from the initial examination and management to definitive treatment. Furthermore, an algorithm is presented to help the clinician approach and treat these patients.

Ultrastructural analysis on lumbar disc herniation using surgical specimens: role of neovascularization and macrophages in hernias.

Study Design. The mechanisms responsible for the spontaneous regression of lumbar disc herniation (LDH) were studied by examining herniated tissue collected at operation from patients with LDH. Objective. The aim of the present study was to investigate the role of neovascularization and macrophages in hernias when spontaneous regression of LDH occurred. Summary of Background Data. Spontaneous regression of LDHs has already been demonstrated by diagnostic imaging with tools such as magnetic resonance imaging. However, there have been few studies on the mechanisms of spontaneous regression based on pathologic examination of herniated tissue. In particular, there has been no detailed work on the role of macrophages, which are thought to be closely associated with spontaneous regression. Methods. The magnetic resonance imaging and operative findings of 73 patients who underwent surgery were investigated, and specimens collected during surgery were examined by light and transmission electron microscopy. Results. Capillaries that invade the hernia and macrophages derived from monocytes migrating out of these capillaries are considered to be important factors in the regression of the herniated disc. Macrophages contain lysosomes filled with collagen-degrading enzymes that break down substances after phagocytosis, whereas primary lysosomes are secreted by these cells and break down intercellular substances such as collagen. Both of these mechanisms are closely involved in the regression of herniation. Conclusion. The inflammatory response that occurs around hernia tissue in the epidural space is believed to play an important role in herniated disc resorption, although it may also have a harmful effect on the adjacent nerve root. Therefore, control of the inflammatory reac-tion is an important challenge when treating patients with disc herniation.

Synapse involvement of the dorsal horn in experimental lumbar nerve root compression: a light and electron microscopic study.

Study Design. This study was aimed at investigating changes in the dorsal horn of the lumbar cord induced by mechanical compression using an in vivo model. Objective. To determine the effect of axonal flow disturbance in the dorsal horns induced by nerve root compression. Summary of Background Data. Few studies have looked at changes of synapses within the dorsal horn caused by disturbance of axonal flow and the axon reaction as a result of mechanical compression of the dorsal root. Methods. In mongrel dogs, the 7th lumbar nerve root was compressed for 1 week, or 3 weeks using a clip. After intravenous injection of Evans blue albumin, they were observed under a fluorescence microscope for the purpose of clarifying the function of the blood-spinal cord barrier. Morphologic changes of the synapses in the dorsal horns secondary to the nerve fiber degeneration were examined by light and electron microscope. Changes on immuno-staining for substance P, calcitonin gene-related peptide, and somatostatin in the dorsal horn were also examined. Results. Light microscope observation conducted 1 week after compression of the nerve roots revealed Wallerian degeneration of the myelinated nerve in the dorsal horn, and fluorescence microscope observation of these areas demonstrated edema formation resulting from damage of the blood-spinal cord barrier. Three weeks after the compression, electron microscope observation revealed shrinkage of the axon terminals, ubiquitous presence of high electron density degeneration and presence of synapses whose contact with synapses was disrupted. Immuno-histochemical studies showed a marked decrease of substance P, calcitonin gene-related peptide, and somatostatin staining in substance gelatinosa with Wallerian degeneration after compression of nerve root. Conclusion. It is important to recognize that compressive disturbance of the nerve roots caused Wallerian degeneration not only at the site of compression of nerve roots but also at the synapses of spinal cord dorsal horns.

Motor neuron involvement in experimental lumbar nerve root compression: a light and electron microscopic study.

Study Design. The aim of this study is to investigate changes in lumbar motor neurons induced by mechanical nerve root compression using an in vivo model. This study is to investigate the changes of lumbar motor neuron induced by mechanical nerve root compression using in vivo model. Objectives. The effect of axonal flow disturbance induced by nerve root compression was determined in lumbar motor neuron. Summary of Background Data. The lumbar motor neuron should not be overlooked when considering the mechanism of weakness, so it is important to understand the morphologic and functional changes that occur in motor neurons of the spinal cord as a result of nerve root compression. However, few studies have looked at changes of neurons within the caused by disturbance of axonal flow, the axon reaction, chromatolysis, and cell death as a result of mechanical compression of the ventral root. Methods. In mongrel dogs, the seventh lumbar nerve root was compressed for 1 week, or 3 weeks using a clip. Morphologic changes of the motor neurons secondary to the axon reaction were examined by light and electron microscopy. Results. Light and electron microscopy showed central chromatolysis of motor neurons in the lumbar cord from 1 week after the start of compression. After 3 weeks, some neurons undergoing apoptosis were seen in the ventral horn. Conclusion. It is important to be aware that, in patients with nerve root compression due to lumbar disc herniation or lumbar canal stenosis, dysfunction is not confined to degeneration at the site of compression but also extends to the motor neurons within the lumbar cord as a result of the axon reaction. Patients with weakness of lower leg should therefore be fully informed of the fact that these symptoms will not resolve immediately after surgery.

Fine structure of cartilage canal and vascular buds in the rabbit vertebral endplate. Laboratory investigation.

OBJECT The vascular terminations (vascular buds) in the bone-disc junction area are structurally very similar to cartilage. In all previous studies to date, however, the roles of cartilage canals and vascular buds were mainly discussed using histological and transparent sections but not electron microscopic sections. The purpose of this study was to clarify the ultrastructure of the vascular bud seen in the bone-disc junction in comparison to the cartilage canal. METHODS Japanese white rabbits from 2 days to 6 months of age were used in this study. The bone-disc junctions were examined by microangiogram and light and electron microscopy, and morphological changes and their association with the age of the animals were noted. RESULTS The fine structure of the vascular bud was similar to that of the cartilage canal that nourished the growing cartilage. They were composed of arteries, veins, capillaries, cells resembling fibroblasts, and macrophages. The capillaries in the cartilage canal were all the fenestrated type. Vascular buds were seen over the entire bone-cartilage interface, with maximum density in the area related to the nucleus pulposus. They projected into the bone-disc junction area from the vertebral body contacting the cartilaginous endplate directly. CONCLUSIONS The results of this study clarify the formation process and ultrastructure of the vascular bud seen in the bone-disc junction. The authors found a strong structural resemblance between the vascular bud and the cartilage canal and hypothesize that the immature cells seen surrounding the cartilage canal and vascular bud represent a common precursor for the 3 main types of connective tissue cells seen during early vertebral development.

A Case of Nerve Root Heat Injury Induced by Percutaneous Laser Disc Decompression Performed at an Outside Institution: Technical Case Report

OBJECTIVE In recent years, percutaneous laser disc decompression (PLDD) has become a routine surgical procedure because it can be performed under local anesthesia and is minimally invasive. However, there is a risk of nerve root and endplate injury owing to heat generated by laser irradiation during PLDD. We recently performed salvage surgery on a patient with heat injury to the L5 nerve root that developed after PLDD. CLINICAL PRESENTATION One month before presenting to our hospital, the patient underwent two sessions of PLDD for lumbar vertebral disk herniation at another institution. The patient developed worsening sciatica, as well as bowel and urinary problems after the PLDD. INTERVENTION We performed salvage surgery after PLDD. The intraoperative findings in the present case included carbon spots in the dura mater of the nerve root and a disc herniation strongly adherent to the nerve roots. These findings indicate that the area adjacent to the nerve roots was damaged by excessive heat during laser irradiation. CONCLUSION When salvage surgery is performed after a PLDD procedure, disc and nerve root injuries owing to laser heat energy must be considered.

Atlantoaxial subluxation-induced myelopathy in cleidocranial dysplasia. Case report.

The authors describe the clinical course and treatment of a patient with cleidocranial dysplasia in whom spastic myelopathy developed due to atlantoaxial subluxation. This 27-year-old woman with cleidocranial dysplasia and a history of atlantoaxial subluxation presented with spastic myelopathy. Surgery was performed twice for cervical myelopathy and atlantoaxial subluxation, including laminectomy at the atlas and cervicooccipital fusion in which the Luque rod system was used, as well as C1-2 fusion via the transpharyngeal route. Solid bone fusion was achieved by 7 months postsurgery. Postoperative magnetic resonance imaging studies demonstrated that spinal cord compression was relieved, but atrophy persisted. At 2 years postsurgery there was no neurological disease progression, but spasticity persisted. The patient could walk with a cane. Cleidocranial dysplasia is an extremely rare cause of myelopathy in patients with atlantoaxial subluxation; the authors know of only two reports of this condition. When managing cleidocranial dysplasia, the practitioner should always be aware that atlantoaxial subluxation may be the cause of cervical myelopathy.

Histological findings of avulsion tear-type medial patellofemoral ligament injury in acute patellar dislocation

Acute patellar dislocation is a common injury that occurs during a variety of activities and accounts for 2–3% of knee injuries.1 Since 1990, especially over the past 5 years, more attention has focused on the medial patellofemoral ligament (MPFL) of the medial retinacular components. In several biomechanical studies, the MPFL has proved to be the primary restraint to lateral translation of the patella among the medial patellar stabilisers, and many clinical findings have shown that acute patellar dislocation is associated with MPFL injuries at a high rate.2–9 In 1999, Nomura6 classified MPFL injury in acute patellar dislocation into two types, avulsion tear and substantial tear. An avulsion tear is a detachment-type injury limited to the undersurface of the MPFL at the femoral attachment. It was suspected that this injury may result from a specific structure of the MPFL at the femoral attachment. This study was to evaluate the histological findings of the avulsion tear-type injury of the MPFL in acute patellar dislocation. A 23-year-old woman sustained initial dislocation of the left knee while climbing a step (case 1). Five days after the injury, we …

Vasomotion of intraradicular microvessels in rat.

Study Design. This study is to investigate the changes of vasomotion of intraradicular microvessels in vivo. Objective. We have observed microvascular corrosion casts of the lumbar nerve root by scanning electron microscopy and used an immunohistochemical technique to investigate the presence and distribution of autonomic and sensory nerve in blood vessels of the nerve root. Summary of Background Data. It is generally considered that the genesis of radiculopathy associated with the degenerative conditions of the spine may result from both mechanical compression and circulatory disturbance. However, the neurogenic control of intraradicular blood flow has received little attention in the past. Methods. For three-dimensional observation of intraradicular vessels, we used scanning electron microscopic examination of microvascular corrosion casts in ten Wister rats. To investigate the mechanism of vasomotion of the nerve root, we used immunohistochemical methods. The sections were incubated overnight with antisera to tyrosine hydroxylase, choline acetyl transferase, substance P, calcitonin-gene-related peptide, vasoactive intestinal peptide, somatostatin, neuropeptide Y, leucine-enkephalin, cholecystokinin octapeptide, brain-nitric oxide synthase, and endothelium-nitric oxide synthase. Abidin-biotin complex method was used as the immunohistochemical procedure and the sections were observed under the light microscope. Results. The general view of whole vascular casts of the lumbar spinal cord and nerve roots showed a high density of vessels. Bifurcation or anastomoses of capillaries approximately took place at right angles in a T-shaped pattern and capillaries showed a lot of ring-like compressions. This ring-like compression on the cast may represent a vascular sphincter in the microvessels. This study also reveals the existence of perivascular adrenergic, cholinergic, peptidergic, and nitroxydergic innervation with a possible role in neurogenic regulation of nerve root circulation. Conclusion. Perivascular nerve plexuses around intraradicular microvessels suggest that the autonomic nerves play an important role in intraradicular circulation.