Stepwise reduction of bone mineral density increases the risk of cage subsidence in oblique lumbar interbody fusion patients biomechanically: an in-silico study.

BACKGROUND: Cage subsidence causes poor prognoses in patients treated by oblique lumbar interbody fusion (OLIF). Deterioration of the biomechanical environment initially triggers cage subsidence, and patients with low bone mineral density (BMD) suffer a higher risk of cage subsidence. However, whether low BMD increases the risk of cage subsidence by deteriorating the local biomechanical environment has not been clearly identified. METHODS: OLIF without additional fixation (stand-alone, S-A) and with different additional fixation devices (AFDs), including anterolateral single rod screws (ALSRs) and bilateral pedicle screws (BPSs) fixation, was simulated in the L4-L5 segment of a well-validated finite element model. The biomechanical effects of different BMDs were investigated by adjusting the material properties of bony structures. Biomechanical indicators related to cage subsidence were computed and recorded under different directional moments. RESULTS: Overall, low BMD triggers stress concentration in surgical segment, the highest equivalent stress can be observed in osteoporosis models under most loading conditions. Compared with the flexion-extension loading condition, this variation tendency was more pronounced under bending and rotation loading conditions. In addition, AFDs obviously reduced the stress concentration on both bony endplates and the OLIF cage, and the maximum stress on ALSRs was evidently higher than that on BPSs under almost all loading conditions. CONCLUSIONS: Stepwise reduction of BMD increases the risk of a poor local biomechanical environment in OLIF patients, and regular anti-osteoporosis therapy should be considered an effective method to biomechanically optimize the prognosis of OLIF patients.

Deterioration of the fixation segment's stress distribution and the strength reduction of screw holding position together cause screw loosening in ALSR fixed OLIF patients with poor BMD.

The vertebral body's Hounsfield unit (HU) value can credibly reflect patients' bone mineral density (BMD). Given that poor bone-screw integration initially triggers screw loosening and regional differences in BMD and strength in the vertebral body exist, HU in screw holding planes should better predict screw loosening. According to the stress shielding effect, the stress distribution changes in the fixation segment with BMD reduction should be related to screw loosening, but this has not been identified. We retrospectively collected the radiographic and demographic data of 56 patients treated by single-level oblique lumbar interbody fusion (OLIF) with anterior lateral single rod (ALSR) screw fixation. BMD was identified by measuring HU values in vertebral bodies and screw holding planes. Regression analyses identified independent risk factors for cranial and caudal screw loosening separately. Meanwhile, OLIF with ALSR fixation was numerically simulated; the elastic modulus of bony structures was adjusted to simulate different grades of BMD reduction. Stress distribution changes were judged by computing stress distribution in screws, bone-screw interfaces, and cancellous bones in the fixation segment. The results showed that HU reduction in vertebral bodies and screw holding planes were independent risk factors for screw loosening. The predictive performance of screw holding plane HU is better than the mean HU of vertebral bodies. Cranial screws suffer a higher risk of screw loosening, but HU was not significantly different between cranial and caudal sides. The poor BMD led to stress concentrations on both the screw and bone-screw interfaces. Biomechanical deterioration was more severe in the cranial screws than in the caudal screws. Additionally, lower stress can also be observed in fixation segments' cancellous bone. Therefore, a higher proportion of ALSR load transmission triggers stress concentration on the screw and bone-screw interfaces in patients with poor BMD. This, together with decreased bony strength in the screw holding position, contributes to screw loosening in osteoporotic patients biomechanically. The trajectory optimization of ALSR screws based on preoperative HU measurement and regular anti-osteoporosis therapy may effectively reduce the risk of screw loosening.

The Mismatch Between Bony Endplates and Grafted Bone Increases Screw Loosening Risk for OLIF Patients With ALSR Fixation Biomechanically.

The mismatch between bony endplates (BEPs) and grafted bone (GB) triggers several complications biomechanically. However, no published study has identified whether this factor increases the risk of screw loosening by deteriorating the local stress levels. This study aimed to illustrate the biomechanical effects of the mismatch between BEP and GB and the related risk of screw loosening. In this study, radiographic and demographic data of 56 patients treated by single segment oblique lumbar interbody fusion (OLIF) with anterior lateral single rod (ALSR) fixation were collected retrospectively, and the match sufficiency between BEP and GB was measured and presented as the grafted bony occupancy rate (GBOR). Data in patients with and without screw loosening were compared; regression analyses identified independent risk factors. OLIF with different GBORs was simulated in a previously constructed and validated lumbosacral model, and biomechanical indicators related to screw loosening were computed in surgical models. The radiographic review and numerical simulations showed that the coronal plane's GBOR was significantly lower in screw loosening patients both in the cranial and caudal vertebral bodies; the decrease in the coronal plane's GBOR has been proven to be an independent risk factor for screw loosening. In addition, numerical mechanical simulations showed that the poor match between BEP and GB will lead to stress concentration on both screws and bone-screw interfaces. Therefore, we can conclude that the mismatch between the BEP and GB will increase the risk of screw loosening by deteriorating local stress levels, and the increase in the GBOR by modifying the OLIF cage's design may be an effective method to optimize the patient's prognosis.

Negative pressure pulmonary edema after percutaneous endoscopic interlaminar lumbar discectomy-a case report.

BACKGROUND: Negative pressure pulmonary edema (NPPE) is a rare complication that is more prevalent in young patients. NPPE usually results from acute upper airway obstruction, which is most commonly caused by laryngospasm during extubation. NPPE is characterized by the sudden onset of coughing, hemoptysis, tachycardia, tachypnea, and hypoxia, and is dramatically improved with supportive care, which prevents severe sequelae. To our knowledge, there is no report of a patient developing NPPE after percutaneous endoscopic interlaminar lumbar discectomy. CASE PRESENTATION: Herein, we report the case of a 22-year-old amateur basketball player with L5/S1 disc herniation who developed NPPE during extubation after general anesthesia for a minimally invasive spinal surgery (percutaneous endoscopic interlaminar lumbar discectomy). The NPPE was treated by maintaining the airway patency, applying positive-pressure ventilation, administering dexamethasone and antibiotics, and limiting the volume of fluid infused. The patient had an uneventful postoperative course, and was discharged to his home on postoperative day 3. CONCLUSIONS: Although NPPE is an infrequent complication, especially in patients undergoing percutaneous endoscopic interlaminar lumbar discectomy, this case report highlights the importance of early diagnosis and prompt treatment of NPPE to prevent the development of potentially fatal complications.

Multicenter Study on Observation of Acute-phase Responses After Infusion of Zoledronic Acid 5 mg in Chinese Women with Postmenopausal Osteoporosis.

OBJECTIVE: It has been reported that acute-phase reactions (APR) after infusion of 5 mg zoledronic acid for the first time is common. This study surveyed the incidence and characteristics of APR in Chinese postmenopausal women receiving 5 mg zoledronic acid intravenously for osteoporosis and to evaluate the efficacy of non-steroidal anti-inflammatory drugs (NSAID) in preventing or alleviating APR following the first 5 mg zoledronic acid infusion. METHODS: A total of 2601 patients with an average age of 68.14 ± 9.89 years and a mean body mass index of 22.90 ± 3.24 kg/m2 from 62 centers in China were treated with 5 mg zoledronic acid intravenously for the first time. The incidence of fever and pain were observed in these patients, and the time of fever or pain onset and duration, and the intensity of fever and grade of pain were also recorded. The dosage, duration, and efficacy of NSAID and safety outcomes were also documented. RESULTS: At the end of the study, 18 patients are eliminated due to incomplete records of temperature. The incidence of fever was 28.65% (740/2583) within 7 days following zoledronic acid infusion; 98.34% (727/740) occurred at 1.03 ± 0.66 days after infusion and lasted 1.72 ± 0.93 days. A total of 456 (17.53%) patients had newly onset pain (312 of 1187, 26.28%) or experienced pain aggravation (144 of 1414, 10.18%), which mostly occurred within 3 days after zoledronic acid infusion. A total of 1246 (47.6%) patients had received NSAID for a median time of 2.63 ± 2.45 days. Using NSAID for at least 2 days could decrease body temperature by 0.54 ± 0.86°C, increase the percentage of pain-free patients by 6.17%, and reduce the percentage of patients with moderate to severe pain by 8.7%. CONCLUSIONS: Compared with Western populations, Chinese patients had a higher rate of fever and pain after their first zoledronic acid infusion. These symptoms were often mild to moderate in intensity and transient in duration. NSAID could effectively reduce the incidence and severity of such APR.

Complications of Lumbar Disc Herniation Following Full-endoscopic Interlaminar Lumbar Discectomy: A Large, Single-Center, Retrospective Study.

BACKGROUND: The new surgical procedure of full-endoscopic interlaminar lumbar discectomy (FILD) has achieved favorable effects in the treatment of lumbar disc herniation (LDH). Along with the wide range of applications of FILD, a series of complications related to the operation has gradually emerged. OBJECTIVE: To describe the types, incidences, and characteristics of complications following FILD and to explore preventative and treatment measures. STUDY DESIGN: Retrospective, observational study. SETTING: A spine center affiliated with a large general hospital. METHOD: In total, 479 patients with LDH underwent FILDs that were performed by a single experienced spine surgeon between January 2010 and April 2013. Data concerning the complications were recorded. RESULTS: All 479 cases successfully underwent the procedure. A total of 482 procedures were completed. The mean follow-up time was 44.3 months with a range of 24 to 60 months. The average patient age was 47.8 years with a range of 16 to 76 years. Twenty-nine (6.0%) related complications emerged, including 3 cases (0.6%) of incomplete decompression in which the symptoms gradually decreased following 3 - 6 weeks of conservative treatment, 2 cases (0.4%) of nerve root injury in which the patients recovered well following 1 - 3 months of neurotrophic drug and functional exercise treatment, 15 cases (3.1%) of paresthesia that gradually improved following 1 - 8 weeks of rehabilitation exercises and treatment with mecobalamin and pregabalin, and 9 cases of recurrent herniation (1.9%). The latter condition was controlled in 4 cases with a conservative method, and 5 of these cases underwent reoperations that included 3 traditional open surgeries and 2 FILDs. Furthermore, the complication rate for the first 100 cases was 18%. This rate decreased to 2.9% for cases 101 - 479. The incidence of L4-5 herniation (8.2%) was significantly greater than that of L5-S1 (4.5%). LIMITATIONS: This is a retrospective study, and some bias exists due to the single-center study design. CONCLUSION: FILD is a surgical approach that has a low complication rate. Incomplete decompression, nerve root injury, paresthesia, and recurrent herniation were observed in our study. Some effective measures can prevent and reduce the incidence of the complications including strict indications for surgery, a thorough action plan, and a high level of surgical skill. Key words: Complication, lumbar disc herniation, lumbar discectomy, endoscopic, inter-laminar discectomy, minimally invasive spine surgery.

[Clinical characteristics and stage I operation of anterior and posterior approaches for the treatment of cervicothoracic junction (C7T1) fracture-dislocation].

OBJECTIVE: To summary the characteristics of cervicothoracic junction (C7T1) fracture-dislocation,and explore the surgical treatment of combined anterior-posterior procedure. METHODS: From January 2005 to March 2010,8 cases of cervicothoracic junction (C7T1) fracture-dislocation were treated by stage I operation through anterior and posterior approacheg, supplemented by non-structural bone graft. All patients were male with a mean age of 45.0 years old ranging from 32 to 68 years. Six cases were diagnosed clearly by CT scan but with normal cervical spine X-ray film at admission. According to AO classification, 4 cases were of type B, 4 cases of type C, with unilateral locked articular process in 2 cases, bilateral in 2 cases. Preoperative MRI showed intervertebral disc injury in 6 cases. RESULTS: The average operation time was 246.3 min ranging from 150 to 320 min. The blood loss was with an average of 307.5 ml (150 to 600 ml). One patient got hoarseness but recovered without special treatment 6 months later; No other complications happened. One patient of preoperative Frankel grade A died, the remaining patients were followed up from 12 to 63 months (38.6 months in average). These fracture-dislocations were completely reduction after operation, healed with bony union 12 months later, and no pseudoarthrosis. The function of the spinal cord improved obviously at the final follow-up, 1 patient of preoperative grade A had died,and the spinal cord function of the other one had no significant changes,the 2 cases of grade B recovered to C and D respectively, 1case recovered from grade C to D, and 3 case recovered from D to E. CONCLUSION: Cervicothoracic junction (C7T1) fracture-dislocation is a rare clinical spine trauma, and missed easily. The CT is a necessary complement to these patients highly suspected C7T1 fracture-dislocation but with negative cervical spine X-ray film. The patients diagnosed clearly could receive stage I operation of anterior and posterior approaches, supplemented with non-structural bone graft.

[The mid-term follow-up of Coflex non-fusion internal fixation in the treatment of degenerative lumbar disease].

OBJECTIVE: To summarize the mid-term effectiveness of Coflex non-fusion internal fixation treatment of degenerative lumbar disease. METHODS: From October 2008 to December 2010, a retrospective analysis was carried out on 39 patients (29 males and 10 females) diagnosed as degenerative lumbar disease and treated with Coflex interspinous dynamic device, who had been followed up for 1 year at least, the average age was 45.5 years (range, 23 - 67 years). The results were assessed by Japanese Orthopedic Association (JOA) scores, visual analogue scale (VAS) scores, Oswestry disability index (ODI) scores and SF-36 scores; and the range of mobility (ROM), intervertebral disc height of the responsible and adjacent segments were measured on X-film before the operation and at last follow-up. Observed the therapeutic effect of the patients and compared the effect on the patients of different body mass index (BMI) and different age by the One-way analysis of variance and paired t test. RESULTS: The 39 patients were followed up for 30.9 months (range, 12 - 37 months). At the last follow-up, JOA, ODI, VAS and SF-36 scores were improved by 70% ± 12%, 54% ± 12%, 77% ± 10% and 51% ± 9%, and were statistically significant (t = -33.289, 26.448, 26.596 and -20.772, P = 0.00). Patients with BMI ≥ 25 kg/m(2) had lower improvement rates in the scores than those with BMI < 25 kg/m(2) (F = 10.561, 5.850, 5.651 and 6.519, P < 0.05). The patients were 50 years older or younger couldn't affected the improvement rates in the scores statistically (P > 0.05). There were no significant difference in remaining disc height (P > 0.05), except that the intervertebral disc height of L4-5 increased slightly compared with the preoperative (t = -2.819, P = 0.008). In addition to the ROM of L3-4, L5-S1 and L1-S1 were not significantly different from the preoperative(P > 0.05), the ROM of L4-5 were decreased (t = 12.598, P = 0.000). CONCLUSIONS: The mid-term effectiveness of Coflex non-fusion interspinous fixation in treatment of degenerative lumbar disease is worthy of recognition, and Coflex combined with Isobar has advantages in the treatment of multi-segment degenerative lumbar disease.

Causes, treatment and prevention of esophageal fistulas in anterior cervical spine surgery.

OBJECTIVE: To evaluate the causes, treatment and prevention of esophageal fistulas after anterior cervical spine surgery. METHOD: Between January 2004 and December 2011, 5 of 2348 patients who underwent anterior cervical surgery in our hospital developed esophageal fistulas (three male and two female patients, average age 34 years). Their diagnoses were cervical injuries (three), cervical spondylosis (one) and cervical tuberculosis (one). Their esophageal fistulas were treated by debridement and exploratory surgery, primary suturing of the perforation and/or sternocleidomastoid myoplasty. If conservative treatment failed or esophageal fistula recurred, plate removal was offered. Postoperative treatment included esophageal rest, enteral nutrition, wound drainage, and antibiotics. Methylene blue was used to evaluate results. RESULT: An esophageal fistula was discovered during anterior cervical surgery in one patient and primary suturing performed. In four patients, fistulas were diagnosed after anterior cervical decompression and fusion. In one of these, only debridement and exploratory surgery were required. In another, a perforation was sutured during debridement and exploratory surgery. In the third, internal fixation was removed because of failure of prolonged conservative treatment. In the fourth, the esophageal fistula recurred repeatedly; he required removal of the hardware and reinforcement with a sternocleidomastoid muscle flap. At 6-48 months follow-up, all patients were in good condition, symptom free, and without cervical instability or infectious spondylitis. CONCLUSION: Successful management of esophageal fistula after anterior cervical spinal surgery depends on primary closure of the perforation with or without muscle flaps, surgical drainage, esophageal rest and nutritional support, and removal of hardware if necessary. Prevention consists of careful surgery and gentle tissue handling.

[Application of n-HA/PA66 composite artificial vertebral body in anterior reconstruction of lower cervical spine fracture and dislocation].

OBJECTIVE: To initially evaluate the application of artificial vertebra of n-HA/PA66 in anterior reconstruction of lower cervical spine fracture and dislocation. METHODS: In this study, 84 patients with lower cervical spine fracture and dislocation received anterior cervical discectomy, spinal canal decompression or subtotal corpectomy, spinal canal decompression and reconstruction by n-HA/PA66 composite artificial vertebral body combined with plate instrumentation. Neurological function was followed up by improvement rate of Frankel and situations of the supporting body was observed by X ray and 3D-CT in 3, 12, 24 months postoperatively. The intervertebral height, physical arc (reflected by Cobb angle) and the locations and fusion rate of the supporting body were assessed in order to evaluate the stability of the cervical spine and alignment improvements. RESULTS: All the patients underwent operation successfully and were followed up for 6 to 24 months with an average of 12 months. The preoperative symptoms were improved to varying degrees. Imaging studies showed that in all cases graft fusion were achieved, and cervical alignments, intervertebral height, cervical spine stability and the locations of the artificial vertebral body were well maintained. No displacement and subsidence of the artificial vertebral body occurred. Postoperative immediate intervertebral height (2.4 ± 0.2) cm, preoperative intervertebral height (1.9 ± 0.1) cm, comparisons of the two groups was statistically significant (q = 2.48, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group intervertebral height was not statistically significant (P > 0.05). Preoperative Cobb angle was 9.8° ± 1.2°, postoperative immediate Cobb angle was 16.6° ± 1.2°, comparisons of the two groups was statistically significant (q = 14.25, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group Cobb angle was not statistically significant (P > 0.05). CONCLUSIONS: n-HA/PA66 artificial vertebral body can provide early cervical spine support and stability and effectively maintain the biological alignment and cervical intervertebral height. It has high rate of graft fusion and is convenient to observe by X-ray. Therefore, n-HA/PA66 can be taken as an ideal graft for anterior lower cervical spine fracture and dislocation operation, but further follow-up study is still required to evaluate the long-term effects.

A simple technique of accessing the L5-S1 disc space for transforaminal endoscopic spine surgery.

Transforaminal endoscopic spine surgery is increasingly used to treat a range of spinal conditions. The success of the surgery requires an accurate insertion of the guide needle and a precise placement of the working cannula and endoscope. However, such a precise placement is challenging for many surgeons to achieve when the pathology is located at the L5-S1 level. On the basis of our years of experience with performing transforaminal endoscopic spine surgery, we have developed a simple technique to help surgeons safely access the L5-S1 level. The technique has been proven intuitive and easy for experienced as well as inexperienced surgeons to learn. The key steps of the technique involve identifying an appropriate entry point on the skin and choosing an accurate trajectory angle for insertion. The purpose of this chapter is to report how to easily identify the entry point and choose a trajectory angle depending on the patient's anatomic characteristics.

[Comparison of screw' inserting angle through the 11th and 12th rib anterior approaches for L1 burst fracture].

OBJECTIVE: To compare screw's inserting angle through the 11th and 12th rib in treating L1 burst fracture, explore effects on inserting screw and postoperative angle. METHODS: From October 2007 to October 2010, 108 patients with L1 brust fracture treated through anterior approach were analyzed,including 68 males and 40 females, aged from 21 to 64 years (mean 38.22 years). All patients were divided into the 11th (A, 51 cases) and 12th (B, 57 cases) approach. The data of operation time,blood loss, duration of incision pain, JOA score, Oswestry score, VAS score, quality of life (SF-36), recovery of nervous function, coronal Cobb angle, included angle between screw and plate were observed. RESULTS: All patients were followed up for 9 to 37 months, mean 23 months. The operation time, blood loss, duration of incision pain, in group A were lower than group B (P<0.05), JOA score, Oswestry score, VAS score, SF-36, recovery of nervous function had no significant differences (P>0.05). There were no differences in Cobb angle before operation, but had significance after operation (P=0.000). There were statistically significance between two group in angle between screw and plate (P=0.000, P=0.003). CONCLUSION: The 11th rib approach for the treatment of L1 burst fracture has less effects on screw, less trauma and less angle between screw and plate.

Novel biodegradable α-TCP/poly(amino acid) composite artificial lamina following spinal surgery for prevention of intraspinal scar adhesion.

Biodegradable copolymer α-TCP/poly(amino acid) composite artificial lamina was prepared and used in goat cervical vertebra resection repair. Cervical 4 was removed by laminectomy, and a vertebra defect of 27 × 9 mm was made. α-TCP/poly(amino acid) composite artificial lamina was inserted in the test group. The efficiency of the copolymer during repair and reconstruction of the goats' vertebra was tested by using X-ray, CT scanning, and histological and biomechanical measurements. In the 24 weeks following the operation, the artificial lamina refrained from shifting, and no dural adhesion pressure was observed. In contrast, the control group suffered from infiltration of soft tissue in the spinal canal, dural pressure and α-TCP/poly(amino acid) degradation. In conclusion, α-TCP/poly(amino acid) composite artificial lamina can significantly prevent scar tissue from infiltrating the spinal canal.

[Bone targeting of antitumor conjugate phenamine acid aryolysine-hexanedioic acid bridge grafting-bisphosphonates].

OBJECTIVE: To develop a new bone targeting antitumor therapy system which uses diphosphonate and bone-seeking nuclide to enhance the coordinated effects of chemotherapy and radiotherapy on bones, and to validate the targeting of the new therapy system in vitro and in vivo. METHODS: Phenamine acid caryolysine was connected to bisphosphonates, and then combined with radioactive nuclide 153Sm to establish a new bone targeting chemotherapeutic and radioactive drug for bone cancers. The targeting of this new therapy system was validated by hydroxyapatite crystal absorbing test and body distribution in vivo methods. RESULTS: The optical spectrum of the phenamine acid caryolysine-bisphosphonates conjugate detected by the nuclear magnetic resonance was consistent with the standard structure of synthesized drugs. The conjugate had good absorbability to hydroxyapatite crystals. The body distribution of the conjugate showed higher radiocounting in bones than in other tissues. CONCLUSION: The conjugate has a structure that is consistent with the active compound targeting bone tumors.

[Analysis of patients with bone injury in Wenchuan earthquake].

OBJECTIVE: To evaluate the patients with bone injury in Wenchuan earthquake. METHODS: From May 12th to June 15th 2008 the data of 1410 patients with bone injury in Wenchuan earthquake were analyzed to evaluate clinical intervention and remedy-managing experience. RESULTS: The 1410 patients average age was from 4 to 103 years old. And 744 cases (52.7%) suffered from blunt injuries, 379 cases (26.9%) from buried injuries, 287 cases (20.4%) from falling injuries; And 1317 cases were with fracture, 93 with limbs soft tissue injuries; 261 patients combined with other parts of injuries including 45 cases with paralysis; 66 cases were with crush syndrome, 25 with gas gangrene, 76 with acute kidney failure, 26 with multiple organ failure. And 912 operations were performed including 402 fracture fixation, 224 debridement, 152 debridement and suture, 85 amputation, 29 implant skin, 8 fixation of joint dislocation, 5 surgical flaps transplantation, 4 nerve and tendon suture, 2 arthroscopes, 1 joint replacement. Among the 66 crush syndrome patients, 49 accepted continuous renal replacement therapy, in which 9 cases were bleeding from named arteries and 20 blood vessels were getting embolism. Among the 1410 cases, 1 died from multiple organ failure. CONCLUSIONS: Among the patients with bone injury in Wenchuan earthquake, the elderly patients are more than the youth; The injuries are always combined with other complications; Opened injuries are polluted severely; It is difficult to deal with the crush syndrome; Paraplegia cases are less, but the amputees are more.

[The predictive value of the Tokuhashi revised scoring system for the survival time of patients with spinal metastases].

OBJECTIVE: To evaluate the predictive value of the Tokuhashi revised scoring system for the life expectancy of patients with spinal metastases. METHODS: A retrospective review of 447 patients with spinal metastases was performed, which comprised 291 men and 156 women with a mean age of 56. 1 years. All of the patients were scored with the Tokuhashi revised scoring system based on the available clinical, pathological and radiographic data. The relation between the survival time and the Tokuhashi revised score was analyzed. RESULTS: The patients had a median survival time of 7. 9 months and a mean Tokuhashi revised score of 8. 23 points. The median survival time of 155 patients with high grade primary tumor of lung, liver, gastrointestinal tract, esophagus, bladder and pancreas was 4. 7 months. The median survival time of 146 patients with low grade primary tumor of thyroid, breast and prostate was 12 months. The median survival time of 146 patients with medium grade primary tumor of kidney, lymphoma, ovary and uterus, and unknown primary tumor was 7. 1 months. The median survival time of 211 patients with the Tokuhashi revised score of 0 to 8 points was 4 months. The median survival time of 147 patients with the Tokuhashi revised score of 9 to 11 points was 10 months. The median survival time of 89 patients with the Tokuhashi revised score of 12 to 15 points was 29 months. The differences between the groups were significant (P<0. 01 or 0. 0001). The Tokuhashi revised score was positively correlated with survival time (r=0. 833, P<0. 001). CONCLUSION: The Tokuhashi revised score could support decision making with reliable estimation of life expectancy of patients with spinal metastases. Surgery could be a better choice to extend life span for those patients with solitary spinal metastasis of slow-growth primary tumor and those with the Tokuhashi revised score of 12 to 15 points.

[Establishment of orthotopic model of MG-63 osteosarcoma].

OBJECTIVE: To establish an orthotopic transplantation model of human osteosarcoma in nude mice. METHODS: The cell suspensions of serial passage of MG-63 cell line with high tumor formation rate were implanted into the distal femur of nude mice. The tumor tissue were treated with routine pathologic HE stain and observed under microscope, and made to the x-ray inspection. RESULTS: In two weeks, the neoplasm was found to grow at local tissue of nude mice, and also found in x-ray film when it was after implant operated for 4 weeks. The typical characteristics of osteosarcoma of tumor tissue were found under microscope. The tumor formation rate of tumor tissue transplantation was 100% and the tumor formation rate of MG-63 cell suspension was 70%. CONCLUSION: The orthotopic transplantation model of osteosarcoma in nude mice is well established and provides a more similar human internal milieu for researches of osteosarcoma.