Postoperative discal pseudocyst and its similarities to discal cyst: A case report.

BACKGROUND: Postoperative discal pseudocyst (PDP) is a rare condition that presents after surgery for lumbar disc herniation. Due to the lack of information, the diagnosis and treatment of PDP remain controversial. Herein, we report a PDP case that occurred following percutaneous endoscopic lumbar discectomy and received conservative treatment. Additionally, we review all the published literature regarding PDP and propose our hypothesis regarding PDP pathology. CASE SUMMARY: A 23-year-old man presented with a relapse of low back pain and numbness in his left lower extremity after undergoing percutaneous endoscopic lumbar discectomy for lumbar disc herniation. Repeat magnetic resonance imaging demonstrated a cystic lesion at the surgical site with communication with the inner disc. The patient was diagnosed as having PDP. The patient received conservative treatment, which resulted in rapid improvement and spontaneous regression of the lesion, and had a favorable outcome in follow-up. CONCLUSION: PDP and discal cyst (DC) exhibit similarities in both histological and epidemiological characteristics, which indicates the same pathological origin of PDP and DC. The iatrogenic annular injury during discectomy might accelerate the pathological progression of DC. For patients with mild to moderate symptoms, conservative treatment can lead to great improvement, even inducing spontaneous regression. However, surgical cystectomy is necessary in patients with neurological deficits and where conservative treatment is ineffective.

Long-term outcomes following en bloc resection for sacral tumor: a retrospective analysis of 93 cases.

Sacral tumors are rare. Appropriate surgical resection is crucial to treat the disease while minimizing disease recurrence. We present the results of 93 patients with sacral tumors to analyze the long-term functional and oncological results of patients undergoing en bloc resection. The medical data between January 2003 and July 2010 was retrospectively reviewed. None of the 93 patients died intra- or postoperatively. Patients undergoing intralesional curettage (range, 6500-25,000 mL; mean, 13,500 mL) lost more blood than those patients with wide excision (range, 1000-8100 mL; mean, 3590 mL). Mean follow-up duration from the time of surgery until most recent clinic visit or death was 44.5 months (range, 6-105 months). This study is an educational tool regarding primary sacral tumors and provides evidence on the treatment. It presents results from a large group of patients with sacral tumor. After follow-up, we did not find that sacrificed nerve roots and surgical margins have an impact on the recurrence of the tumor. Patients undergoing intralesional curettage lost more blood than those patients with wide excision. Postoperative bladder/bowel dysfunction was more severe for patients with removal of S1 and S2.

Green fluorescent protein as marker in chondrocytes overexpressing human insulin-like growth factor-1 for repair of articular cartilage defects in rabbits.

OBJECTIVE: To label the primary articular chondrocytes overexpressing human insulin-like growth factor (hIGF 1) with green fluorescent protein (GFP) for repair of articular cartilage defects in rabbits. METHODS: GFP cDNA was inserted into pcDNA3.1 hIGF 1 to label the expression vector. The recombinant vector, pcGI, a mammalian expression vector with multiple cloning sites under two respective cytomegalovirus promoters/enhancers, was transfected into the primary articular chondrocytes with the help of lipofectamine. After the positive cell clones were selected by G418, G418-resistant chondrocytes were cultured in medium for 4 weeks. The stable expression of hIGF 1 in the articular chondrocytes was determined by in situ hybridization and immunocytochemical analysis and the GFP was confirmed under a fluorescence microscope. Methyl thiazolyl tetrazolium (MTT) and flow cytometer methods were employed to determine the effect of transfection on proliferation of chondrocytes. Gray value was used to analyze quantitatively the expression of type II collagen. RESULTS: The expression of hIGF 1 and GFP was confirmed in transfected chondrocytes by in situ hybridization, immunocytochemical analysis and fluorescence microscope observation. Green articular chondrocytes overexpressing hIGF 1 could expand and maintain their chondrogenic phenotypes for more than 4 weeks. After the transfection of IGF 1, the proliferation of chondrocytes was enhanced and the chondrocytes could effectively maintain the expression of type II collagen. CONCLUSIONS: The hIGF 1 eukaryotic expression vector containing GFP marker gene has been successfully constructed. GFP, which can be visualized in real time and in situ, is stably expressed in articular chondrocytes overexpressing hIGF 1. The labeled articular chondrocytes overexpressing hIGF 1 can be applied in cell-mediated gene therapy as well as for other biomedical purposes of transgenic chondrocytes.

Biomechanical study on pullout strength of thoracic extrapedicular screw fixation.

OBJECTIVE: To identify the biomechanical feasibility of the thoracic extrapedicular approach to the placement of screws. METHODS: Five fresh adult cadaveric thoracic spine from T1 to T8 were harvested. The screw was inserted either by pedicular approach or extrapedicular approach. The result was observed and the pullout strength by pedicular screw approach and extrapedicular screw approach via sagittal axis of the vertebrale was measured and compared statistically. RESULTS: In thoracic pedicular approach, the pullout strength of pedicle screw was 1001.23 N+/-220 N (288.2-1561.7 N)ls and that of thoracic extrapedicular screw approach was 827.01 N+/-260 N when screw was inserted into the vertebrae through transverse process, and 954.25 N+/-254 N when screw was inserted into the vertebrae through the lateral cortex of the pedicle. Compared with pedicular group, the pullout strength in extrapedicular group was decreased by 4.7% inserted through transverse process (P larger than 0.05) and by 17.3% inserted through the lateral cortex (P less than 0.05). The mean pullout strength by extrapedicular approach was decreased by 11.04% as compared with pedicular approach (P less than 0.05). CONCLUSIONS: It is feasible biomechanically to use extrapedicular screw technique to insert pedicular screws in the thoracic spine when it is hard to insert by pedicular approach.