Shuxun Hou

Four-year follow-up results of transforaminal lumbar interbody fusion as revision surgery for recurrent lumbar disc herniation after conventional discectomy

This study investigated the safety, effectiveness, and clinical and radiological outcomes of transforaminal lumbar interbody fusion (TLIF) for recurrent lumbar disc herniation (rLDH) following previous lumbar spine surgery. Seventy-three consecutive patients treated for rLDH between June 2005 and May 2012 were included in the study. The previous surgical procedures included percutaneous discectomy, discectomy with laminotomy, discectomy with unilateral laminectomy, and discectomy with bilateral laminectomy. The level of rLDH was L4-L5 in 51 patients, L5-S1 in 19 patients, and L3-L4 in three patients. All patients underwent reoperation using the TLIF technique. Outcomes were evaluated using the Oswestry disability index (ODI), visual analogue scale (VAS) scores for low back pain and leg pain, and the Japanese Orthopaedic Association (JOA) score, based on the results of physical examinations and questionnaires. The range of motion and disc height index of the operative segment were compared between preoperative and postoperative radiographs. The mean follow-up period was 4.1 years. The VAS scores for low back pain and leg pain, ODI, and JOA score improved significantly between the preoperative and final follow-up evaluations. The mean recovery rate of the JOA score was 89.0%. The disc space height and stability at the fused level were significantly improved after surgery. The fusion rate at the final follow-up was 93.2%. There were no major complications. These results indicate that TLIF can be considered an effective, reliable, and safe alternative procedure for the treatment of rLDH.

Porous Allograft Bone Scaffolds: Doping with Strontium

Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28±0.23 µm/day vs. 2.60±0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes.

Clinical Features and Surgical Management of Spinal Osteoblastoma: A Retrospective Study in 18 Cases

Objectives To investigate the clinical manifestation and surgical outcome of spinal osteoblastoma. Methods From June 2006 to July 2011, 18 patients with spinal osteoblastoma treated surgically were analyzed retrospectively. There were 11 males and 7 females with an average age of 27.5 years（range, 16-38 years). The tumors were located at C5 in 7, C6 in 6, C7 in 3, C6-T1 1 in 1 and T11 in 1. Based on WBB classification, 16 were 1-3 or 10-12 and 2 were 4-9 and 1-3. 18 operations had been performed with en bloc resection. A posterior approach was used for 16 patients, and a combined posterior and anterior approach was used for 2 patients. Reconstruction using instrumentation and fusion was performed using spinal instrumentation in 13 patients. We used visual analogue scales (VAS) to evaluate the change of pain before and after the operation, and the McCormick System to assess functional status of the spine. Imaging test was used to review the stability and recurrence rate of spine cord, and the confluence of graft bones. Results All cases were followed up for 24-80 months (average, 38.4 months). The average surgical time was 120.8 minutes (range, 80-220 minutes), with the average intraoperative blood loss of 520 ml (range, 300-1200 ml). During the follow-up period, the VAS grade reduced from 6.46±1.32 to 2.26±1.05 (P <0.05). 15 patients had neurological function improved and 3 remained no change which was evaluated by McCormick scale for spinal function status at final follow-up. Conclusions Spinal osteoblastoma has its own specific radiographic features. There is some recurrence in simple curettage of tumor lesion. The thoroughly en bloc resection of tumor or spondylectomy, bone fusion and strong in Ter fixation are the key points for successful surgical treatment.

A Comparison of Multilevel Anterior Cervical Discectomy and Corpectomy in Patients with 4-level Cervical Spondylotic Myelopathy: A Minimum 2-year Follow-up Study.

Study Design: Retrospective clinical series. Objectives: To compare perioperative parameters, clinical outcomes, radiographic parameters, and complication rates of segmental anterior cervical corpectomy and fusion (sACCF) plus preservation of middle vertebrae with those of multilevel anterior cervical discectomy and fusion (mACDF) in 70 patients with 4-level cervical spondylotic myelopathy (CSM). Methods: Between July 2006 and May 2011, 70 consecutive patients [49 males and 21 females; mean age 56.8 y (range, 38–72 years)] with 4-level CSM were enrolled in this study and divided into sACCF (n=39) group and mACDF (n=31) group. The study compared perioperative parameters, complication rates, clinical parameters, and radiologic parameters. Results: No significant differences between the groups were found in demographic, baseline disease characteristics, operation time, hospital stay, and follow-up time. Significant improvements of clinical outcome were seen from preoperative to postoperative in both groups. Satisfaction was rated as excellent or good by 79.5% of the sACCF group and 80.6% of the mACDF group, which was not a significant difference. Mean postoperative cervical lordosis was significantly greater in the mACDF group than in the sACCF group. Blood loss was significantly greater in the sACCF group than in the mACDF group and instrumentation-related and/or graft-related complication rate significantly lower for the mACDF group. Both sACCF and mACDF groups achieved solid fusion rates (87.1% and 90.3%, respectively). Conclusions: Both mACDF and sACCF provide satisfactory clinical outcomes and fusion rates for 4-level CSM. However, mACDF is associated with better radiologic parameter, less blood loss, and lower instrumentation-related and/or graft-related complication rate.

Irradiation Sterilized Gelatin–Water–Glycerol Ternary Gel as an Injectable Carrier for Bone Tissue Engineering

&NA; Injectable gelatin gels offer an attractive option for filling bone defects. The challenge is to fabricate gelatin gels with optimal gelation properties, which can be irradiation sterilized. Here, a gelatin–water–glycerol (GWG) gel is reported for use as a broad‐spectrum injectable carrier. This ternary gel is high in glycerol and low in water, and remains stable after gamma irradiation at doses (25 kGy). As an injectable gel, it remains a viscous solution at gelatin concentrations ≤2.0%, at room temperature. Its storage modulus increases dramatically and eventually exceeds the loss modulus around 46–50 °C, indicating a transition from a liquid‐like state to an elastic gel‐like state. This ternary gel ranges significantly in terms of storage modulus (12–1700 Pa) while demonstrating a narrow pH range (5.58–5.66), depending on the gelatin concentration. Therefore, it can be loaded with a variety of materials. It is highly cytocompatible compared with saline in vivo and culture media in vitro. When loaded with demineralized bone matrix, the composites show favorable injectability, and excellent osteogenesis performance, after irradiation. These features can be attributed to high hydrophilicity and fast degradability. These findings justify that this ternary gel is promising as an irradiation‐sterilized and universal injectable delivery system. &NA; A gelatin–water–glycerol (GWG) gel can be gamma radiation sterilized but a gelatin hydrogel cannot. Gelatin molecules in the GWG gel are compartmentalized into regions of “available glycerol‐free water”, as demonstrated by bubble formation in irradiated samples. Local gelatin protein concentration is remarkably increased, resulting in an increased viscosity. Therefore, demineralized bone matrix block can still be loaded into irradiated GWG gel. Figure. No caption available.

A new zero-profile, stand-alone Fidji cervical cage for the treatment of the single and multilevel cervical degenerative disc disease

To investigate the clinical and radiological results of the new zero-profile, stand-alone Fidji cervical cage to treat single- and multiple-level cervical DDD, and evaluate the safety and efficiency. Between October 2011 and July 2014, 72 consecutive patients (41 males and 31 females; mean age 50.9years [range, 33-68years]) with cervical DDD who underwent surgery and were followed for more than 2years were enrolled in this study (mean 31.1months, range 24-47months). The study compared clinical outcomes, radiologic parameters and complication rates. The SF-36, VAS, NDI, and JOA scores of all patients were improved significantly after surgery at any time point. (all p<0.05). The C2-C7 Cobb angle and the disc height index (DHI) of all patients were improved significantly after surgery at any time point (all p<0.05). From 3months after surgery to final follow-up the DHI showed a significant reduction comparing 1week after surgery (all p<0.05). The fusion rates were 91.7% (66/72) and the radiologic mean fusion time was 9.9months. Radiological evidence of adjacent segment degeneration (ASD) was observed in 4/41 patients (9.8%). Postoperative complications included epidural hematoma, hoarseness, dysphagia, axial neck pain, and subsidence. The zero-profile, stand-alone Fidji cervical cage for ACDF can be considered an effective, reliable and safe alternative procedure in the treatment of cervical DDD.