[Percutaneous pedicle screw fixation combined expandable tubular retractor in the treatment of spinal metastases]

OBJECTIVE

To investigate the effectiveness of percutaneous pedicle screw fixation combined expandable tubular retractor in the treatment of patients with spinal metastases.

METHODS

In the study, 12 patients of spinal metastases treated with percutaneous pedicle screw fixation combined expandable tubular retractor in our hospital were retrospectively reviewed between June 2017 and October 2019. Among the 12 patients, 9 were males and 3 were females; the median age was 62.5 years [(65.1±2.9) years]. The decompression segment of 7 patients was located at the lower thoracic spine (including 1 patient with incomplete paraplegia) and the decompression segment of 5 patients was located at the lumbar spine; Tomita score was 6.0±0.6. Perioperative data of the patients were reviewed. Visual analog scale (VAS score), Karnofsky score, and Eastern Cooperative Oncology Group (ECOG) score were compared before and after surgery. The patient's survival, adjuvant treatment, and internal fixation failure were observed in the follow-up period.

RESULTS

All the 12 patients had a successful operation with percuta-neous pedicle screw fixation combined expandable tubular retractor. The average operative time, blood loss, and blood transfused of the patients were (247.0±14.6) min, (804.2±222.3) mL and (500.0±100.0) mL, respectively. The average amount of drainage was (240.8±79.3) mL. Drainage tubes were pulled out early postoperative [(3.2±0.3) d], allowing early mobilization. The patients discharged (7.8±0.8) d postoperative. All the patients were followed up for 6-30 months, and the average overall survival time was (13.6±2.4) months. During the follow-up period, 2 patients experienced screw displacement, the internal fixation was stable after conservative treatment and no revision surgery was performed. The VAS of the patients was 7.1±0.2 before surgery, which decreased to 2.3±0.1 and 2.8±0.4 at 3 and 6 months after surgery (P < 0.05). The Karnofsky score of the patients was 59.2±1.9 before surgery, which increased to 75.0±1.9 and 74.2±3.1 at 3 and 6 months after surgery (P < 0.05). The ECOG of the patients was 2.3±0.2 before surgery, which decreased to 1.7±0.1 and 1.7±0.2 at 3 and 6 months after surgery (P < 0.05).

CONCLUSION

For selected patients with spinal metastases, minimally invasive surgical treatment of spinal metastases (percutaneous pedicle screw internal fixation combined with expandable tubular retractor) can effectively relieve the clinical symptoms and improve the quality of life, with satisfactory clinical outcome.

[Measurement of the tibial alignment after total knee replacement without the extramedullary cutting guide]

OBJECTIVE

To evaluate the accuracy and analysis of the influencing factors of the tibia prosthetic coronal alignment after total knee arthroplasty without tibia extramedullary cutting guide.

METHODS

In the study, 76 patients (96 knees) who had primary total knee arthroplasty in Peking University First Hospital from February 2012 to April 2016 were selected retrospectively. All of the cases were performed by the same experienced orthopedic surgeon team. The patients were divided into 2 groups randomly: tibia cutting without guide group and tibia cutting with extramedullary guide group. Lower extremity standard anterior and posterior X-ray films of the knees were taken before and after surgery, and the anatomical tibial angle (AT), the posterior slope angle (PSA) before and after surgery, the tibia component angle (TCA) were measured in the X-ray films. We also recorded the beginning and finishing time of the operation, the operation sequence of the day respectively at the same time. The data were analyzed by correlation analysis, t test and chi square test between the two groups.

RESULTS

The age, gender, body mass index, AT/PSA before the surgery and TCA/PSA after the surgery of the two groups were no significant differences (P>0.05). The rate of 90-TCA≥ 3° was 31.5% (17 knees) and 31% (12 knees) respectively, there were no significant differences (P=0.956) between the two groups. The postoperative TCA of two groups was not correlated with age, gender, body mass index (BMI), operation side (P>0.05), there was also no correlation between the postoperative TCA and the start time of the operation, the whole operation time, and the operation sequence of the day (P>0.05). The two groups were divided into subgroups according to 90-AT before the operation (0°≤90-AT<3°, 3°≤90-AT<5°, 5°≤90-AT<8°, 90-AT≥8°), and there was no difference among them. But we found there was a much higher rate of 90-TCA<3° in the group without cutting guide than the group with extramedullary guide when 90-AT≥8° before the surgery (the rates were 71.4 % and 42.9%, P<0.05).

CONCLUSION

There is no significant difference of the tibia prosthetic coronal alignment accuracy between the tibia cutting without guide and the traditional extramedullary guided bone cutting by experienced surgeons. Only if when patients already have suffered severe malformation of knee joint (90-AT≥8°) before the operation, tibia cutting without cutting guide is more effective to rectify the tibia prosthetic coronal alignment.

[Clinical characteristics and prognosis of cultured negative pyogenic spondylitis]

OBJECTIVE

There are limited data describing the clinical characteristics and prognosis of culture negative pyogenic spondylitis. The aim of this study was to investigate the treatment, prognosis and clinical characteristics of culture negative pyogenic spondylitis.

METHODS

A retrospective study reviewed 74 patients who were diagnosed with spondylitis in Peking University First Hospital from January 2010 to December 2015. A total of 27 patients suffered from pyogenic spondylitis. According to the pathogenic culture results, the patients were divided into two groups: culture negative group and culture positive group. The clinical characteristics and treatment outcomes between the two groups were compared.

RESULTS

The elder were more vulnerable to pyogenic spondylitis, and of the 27 patients, 12 patients were female and 15 male. All patients had no history of administration of antibiotics prior to obtaining culture samples. A causative germ was identified in 14/27 patients (51.9%) with Staphylococcus aureus being the most common pathogen. There was no significant difference between the two groups in the patient's age, gender, visual analogue score (VAS), predisposing factor, clinical symptom, sign and spinal segment (P>0.05). Erythrocyte sedimentation rate (ESR) (P=0.056) and C-reactive protein (CRP) (P=0.040) of culture negative group were lower in contrast to culture positive group. The incidence of vertebral abscess in culture negative group was higher than in culture positive group (P=0.046). After treatment, ESR dropped almost equally in both groups, and CRP dropped faster in the culture positive group (P=0.192). At last, there was no significant difference between the two groups in hospital stay, pain relief, open debridement operation rate, and recurrence rate of infection.

CONCLUSION

ESR and CRP of the culture negative patient were lower than those of the culture positive patient, and the incidence rate of paravertebral abscess was higher than that of the culture positive patient. After administration of antibiotics, there was no significant difference between the two groups in duration of antibiotics, open debridement operation rate and recurrence rate of infection. So, culture negative may not necessarily be a negative prognostic factor for pyogenic spondylitis. However, we should watch out for the drug resistant bacteria or double infection, due to the long term use of wide-spectrum antibiotic in culture negative patients.

[Hydrogen sulfide in cartilage and its inhibitory effect on matrix metalloproteinase 13 expression in chondrocytes induced by interlukin-1β]

OBJECTIVE

To investigate whether endogenous hydrogen sulfide (H2S) was involved in the pathogenesis of osteoarthritis (OA) and its underlying mechanism, to detect H2S and its synthases expression in knee cartilage in patients diagnosed with different severity of OA, and to explore the transcription and expression of gene MMP-13 in chondrocytes treated with IL-1β or H2S.

METHODS

Synovial fluids of the in-patients with different severity of OA hospitalized in Peking University First Hospital were collected for measurement of H2S content using methylene blue assay. Articular cartilages of the patients who underwent knee arthroplasty were collected for the cell culture of relatively normal chondrocytes. The chondrocytes were cultured to the P3 generation and H2S molecular probes were used for detection of endogenous H2S generation in the chondrocytes. Immunocytochemistry was used to detect the localization of H2S synthases including cystathionine β-synthase (CBS), cystathionine-γ-lyase (CSE), and mercaptopyruvate sulfurtransferase (MPST) in OA chondrocytes. Western blot was used to quantify the protein expressions of CSE, MPST, and CBS in cartilage tissues of the patients who were diagnosed with OA and underwent knee arthroplasty. The relatively normal human chondrocytes were cultured to passage 3 and then divided into 4 groups for different treatments: (1)the normal control group, no reagent was added; (2)the IL-1β group, 5 μg/L of IL-1β was added; (3)the IL-1β+H2S group, 200 μmol/L of NaHS was added 30 min before adding 5 μg/L of IL-1β;(4)the H2S group, 200 μmol/L of NaHS was added. The transcription and expression of gene MMP-13 in chondrocytes of each group were determined with Real-time PCR and Western blot, respectively. And the total NF-κB p65 and phosphorylated NF-κB p65 in chondrocytes were detected with Western blot.

RESULTS

The content of H2S in the synovial fluid of degenerative knee was (14.3±3.3) μmol/L. Expressions of endogenous H2S and its synthases including CBS, CSE and MPST were present in the cytoplasm of chondrocytes.CSE protein expression in Grade 3 (defined by outerbridge grading) cartilage tissues was significantly increased as compared with that of Grade 1 cartilage tissues (1.67±0.09 vs. 1.26±0.11, P< 0.05). However, no significant difference of CBS or MPST expression among the different groups was observed. The expression of MMP-13 protein in the IL-1βgroup was significantly higher than that in the normal chondrocytes (1.87±0.67 vs. 0.22±0.10, P<0.05), and that in the IL-1β+H2S group was significantly decreased than that in the IL-1β group (0.55±0.11 vs. 1.87±0.67, P< 0.05), and that in the H2S group had no significant difference compared with that in the normal control group. The transcription of MMP-13 protein in the IL-1β group was significantly higher than that in the normal chondrocytes (31.40±0.31 vs. 1.00±0.00, P<0.05), and that in the IL-1β+H2S group was significantly decreased than that in the IL-1β group (24.41±1.28 vs. 31.40±0.31, P<0.05), and that in the H2S group had no significant difference compared with that in the normal control group. The total NF-κB p65 in the IL-1β group was significantly higher than that in the normal chondrocytes (2.13±0.08 vs. 0.73±0.08, P< 0.05), and that in the IL-1β+H2S group was significantly decreased than that in the IL-1β group (1.24±0.13 vs. 2.13±0.08, P<0.05), and that in the H2S group had no significant difference compared with that in the normal control group. The phosphorylated NF-κB p65 in IL-1β group was significantly higher than that in the normal chondrocytes (1.30±0.13 vs. 0.19±0.04, P<0.05), and that in IL-1β+H2S group was significantly decreased than that in the IL-1β group (0.92±0.26 vs. 1.30±0.13, P<0.05), and that in the H2S group had no significant difference compared with that in the normal control group.

CONCLUSION

H2S affected the cartilage degeneration by partly inhibiting the degradation of extracellular matrix.

[Bone marrow mesenchymal stem cells in Sprague-Dawley rat model of osteoarthritis]

OBJECTIVE

To investigate the efficacy of single time intra-articular different concentration of allogeneic bone marrow mesenchymal stem cells (BM-MSCs) injection in the treatment of Sprague-Dawley (SD) rat model of osteoarthritis (OA).

METHODS

In the study, 32 SD rats were equally randomized into 4 groups: control group, high concentration group (1×10(7)/mL BM-MSCs), low concentration group (5×10(6)/mL BM-MSCs) and high vs. low concentration group. The two knees of each rat were set up to a pair. The induction of OA was performed surgically randomly at one side in model group, and bilaterally in the other groups, which were through anterior cruciate ligament transaction (ACLT) and medial meniscus excising. After the operation, the SD rats were allowed free movement. Four weeks later, different concentrations of allogeneic BM-MSCs isolated from the SD rats, expanded in vitro and suspended in phosphate buffered solution (PBS) were delivered in the articular cavity of both knees; PBS was used as the control. After injection, we excised the femoral nerve and sciatic nerve to disuse the low limb. The cartilage histological sections of knees were scored by Mankin scoring system to assess the severity of the pathology. mRNA of collagen II was detected by real time polymerase chain reaction (RT-PCR). eGFP was detected by fluorescence microscope. Assessments were carried out 4 weeks after the operation in model group, and 3 weeks after injection in the other groups.

RESULTS

Mankin scores of the BM-MSCs side and control side were 6.60±0.40 vs. 10.00±0.32 in low concentration group (P<0.05), and 5.40±0.51 vs. 9.60 ±0.51 in high concentration group (P<0.05). Mankin scores of high vs. low concentration group were 6.40±0.51 vs. 7.60±0.75 (P>0.05). mRNA expression of collagen II of the BM-MSCs side in low concentration group was 106%±1% in contrast to the control side. As in high concentration group it was 108%±1%, and 102%±1% in high vs. low concentration group. Labeled BM-MSCs were detected unexpectedly in the synovial membrane but not in cartilage tissue three weeks from injection.

CONCLUSION

BM-MSCs could promote cartilage repair and inhibit OA progression through a trophic mechanism. There was no difference between the two concentrations.