Mechanical stress and bone metabolism

Mechanical stress (MS) is one of the most important factor regulating bone metabolism. However, little is known about the mechanism by which MS contribute to this important biological event. In this paper I will present a brief overview of the hypotheses and data so far presented as well as the ongoing researches elsewhere.     

Callotasis lengthening in patients with brachymetacarpia

Callotasis lengthening is an established method, but few cases of metacarpal lengthening have been reported. The authors performed callotasis lengthening to treat brachymetacarpia in six digits in three patients. The patient age at the time of distraction ranged from 10 to 19 years. The period of application of an external fixator averaged 13.9 weeks (range 10-19 weeks). All the metacarpals achieved the target length, and all patients were satisfied with the esthetic improvement. The length of the metacarpal distraction averaged 15.2 mm (range 10-18 mm). Complete consolidation of the transport gap was achieved for five of six digits. One digit that had a history of previous lengthening required bone graft. The average healing index was 62.3 days/cm. There were no serious complications. In four digits, the range of flexion of the metacarpophalangeal joint was increased after lengthening, and this enabled the patient to use the digit easily in a palmar grasp. Brachymetacarpia is an appropriate indication for callotasis lengthening in congenital deformities of the upper extremities.     

Minimal curettage,multiple drilling,and continuous decompression through a cannulated screw for treatment of calcaneal simple bone cysts in children

This report concerns a series of 12 patients with simple bone cysts of the calcaneus, who were treated between 1988 and 2000 by a minimal surgical intervention of curettage, multiple drilling and continuous decompression through insertion of a cannulated screw. Inserted screws were made of titanium in 8 cases and ceramics in 4 cases. The mean operative time was 58.8 +/- 25.4 minutes, and complete healing was achieved in 11 cases after 9.2 +/- 6.4 months. One patient needed an additional surgery for replacement of a titanium screw. Final results were excellent after a mean follow up of 91 +/- 52.1 months. This series of patients represents one of the largest reported series of calcaneal simple bone cyst in conjunction with long-term follow-up. Our technique of minimal curettage, drilling and continuous decompression with a cannulated screw insertion is considered to be a good option for management of simple bone cysts of the calcaneus.     

Long-term results after primary repairs of zone 2 flexor tendon lacerations in children younger than age 6 years

In young children, methods of primary flexor tendon repair in the digital canal are controversial. The authors reviewed 12 children younger than age 6 years with zone 2 flexor tendon repairs. The mean follow-up period was 8 years. In all cases, the flexor digitorum profundus tendons were repaired according to the Kessler modified technique and the hands were immobilized by an above-elbow cast. As for postoperative complications, there were no fingers with tendon rupture and two fingers with tendon adhesion. One finger needed tenolysis. The total active motion (TAM) in the interphalangeal joints evaluated with the Strickland formula averaged 155 degrees, and the TAM percentage averaged 89% (range 74%-100%). Eleven patients had an excellent result and one had a good result. The percentage phalangeal length averaged 99% (range 96%-100%). Functional motion and nearly normal growth of the finger can be expected after primary zone 2 flexor tendon repairs in children younger than age 6 years.     

Rupture of previously documented asymptomatic unruptured aneurysms--aneurysm size: risk factor for aneurysm rupture

The natural history of asymptomatic unruptured aneurysms is not clear. We conducted a follow up study of 100 patients (since 1993) with 122 asymptomatic unruptured aneurysms that had not been operated on. We report five patients with previously documented asymptomatic unruptured aneurysms smaller than 10 mm in diameter that subsequently ruptured. Among the 100 patients, five had suffered subarachnoid hemorrhage (SAH) due to rupturing of an aneurysm. Of the 5 cases, 1 was male and 4 were female, with ages ranging from 59-73 years (mean age, 68 years). The aneurysms were on the MCA in 3, on the BA-SCA in 1, on the IC-PC in 1. The maximal diameter of the aneurysms at diagnosis ranged from 4.5 to 8 mm. The period from discovery to SAH was from 4 to 69 months and the cumulative rate of rupture of the aneurysms was 1.5 percent per year. Four of the 5 cases increased in size after the rupture. In our series, 2 of the 5 cases showed enlargement and the development of an aneurysmal bleb in the follow up MRA and 3D-CTA. The present study demonstrates that five asymptomatic unruptured aneurysms less than 10 mm in diameter subsequently ruptured. We ought to seriously consider the assertion published in the New England Journal of Medicine (Dec. 10, 1998), that unruptured aneurysms less than 10 mm in diameter have a very low probability of subsequent rupture.     

Usefulness of dynamic digitized cerebral parenchymography for cerebral vascular disease

Aortic arch injections according to Theron's method have been performed in patients with cerebral ischemia. Digital subtraction angiograms with modified windowing (low and narrow) have been used for better visualization of cerebral parenchymal condition. This "cerebral parenchymography" allows much easier understanding of cerebral parenchymal vascularization on angiographic imaging. Although further study is necessary to estimate accurate cerebral blood flow, this technique can enable an easy and quick understanding of the overall cerebral hemodynamics.     

Indication and operative techniques of extended right hepatic lobectomy for advanced gallbladder cancer

Gallbladder cancer extends directly to the hepatic hilum and/or the right portal pedicle in the hepatic hilum type and the bed and hilum type of disease. Extended right hepatic lobectomy (ERHL), caudate lobectomy, lymph node dissection, and biliary reconstruction are necessary for radical resection of the tumor. It was previously thought that this extensive surgery carried high risk, with a hospital death rate of 20%, and had little survival benefit. However, it is now feasible with lower risk due to improvement in biliary decompression techniques, prevention of intrahepatic segmental cholangitis, introduction of preoperative portal embolization, etc. Long-term survival has been achieved after surgery unless there is hepatic, peritoneal, or paraaortic metastasis. Hilar hepatic involvement is more advanced in gallbladder cancer than in bile duct cancer, and portal vein resection and reconstruction are inevitable. All six such patients in our department over the past two years underwent concomitant portal reconstruction and have survived postoperatively.     

A case of solitary neurocysticercosis of unknown transmission route

We report a case of solitary neurocysticercosis of unknown transmission route. A 26-year-old male was taken to our hospital with a history of general convulsions. On admission, physical and neurological findings were normal. On the basis of neuroimaging (computed tomography scan and magnetic resonance imaging), initial diagnosis was brain abscess and the patient was treated with antibiotics. Two months later, the patient, at times, presented a loss of consciousness. The follow-up MRI revealed that the enhanced lesion became enlarged and perifocal edema became evident, so the patient was surgically treated. By histopathological examination, the lesion was diagnosed as a cysticercus. The immunoserologic assay gave a positive result for the disease. Postoperatively, the symptoms improved. Cerebral cysticercosis is the most common parasitic disease of the central nervous system, but rare in Japan. Therefore its diagnosis remains difficult, especially in the case of solitary cerebral cysticercosis, which has been reported only 7 times in Japan. The pathological examination or the immunoserologic assay should be taken into consideration to obtain definitive diagnosis of cerebral cysticercosis.     

Endotoxin removal in septic shock

Endotoxin adsorption therapy with a column containing polymyxin B-immobilized fiber (PMX-DHP) has been widely applied in the treatment of endotoxin-induced septic shock in Japan. Recently, the indications for PMX-DHP have been expanded as it has become clear that anandamide can be removed from the bloodstream with PMX-DHP. On the other hand, continuous hemodiafiltration with a polymethyl methacrylate (PMMA) membrane hemofilter(PMMA-CHDF) is performed to remove various humoral mediators from the bloodstream in the ICU in many hospitals because it has been accepted that those humoral mediators play a more important role in the pathogenesis of septic shock than endotoxins. According to our own results, there were no differences in the endotoxin removal rate, anandamide removal rate, and survival rate with or without PMX-DHP during PMMA-CHDF in the treatment of patients with septic shock. These results indicate that there is no need to perform PMX-DHP for septic shock as long as PMMA-CHDF is performed, and that the indications for PMX-DHP should be circumspectly investigated again.