Publications by authors named "Yao Nuzhao"

5 Publications

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Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2015 Oct;29(10):1265-8

Objective: To explore the safety and effectiveness of graded infusion of bone cement in the unipedicular percutaneous vertebroplasty (PVP) for Kummell's disease.

Methods: Eighteen patients with Kummell's disease were treated by unipedicular PVP with graded infusion of bone cement between January 2012 and January 2014. Of 18 cases, 6 were male and 12 were female, aged from 65 to 88 years (mean, 75 years), with a disease duration from 3 to 32 months (mean, 11.6 months). The bone mineral density was measured by dual-energy X-ray absorptiometry; the T value ranged from -4.0 to -2.8 (mean, -3.4). Affected segments included T11 in 3 cases, T12 in 10 cases, L1 in 3 cases, and L2 in 2 cases. X-ray films were taken after operation to observe bone cement leakage and anterior height changes of affected vertebrae. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to assess pain status and functional activity.

Results: All cases underwent smoothly unipedicular PVP and were followed up 12-26 months (mean, 14 months). Cement leakage occurred in 4 patients, including 1 case of anterior paravertebral soft tissue leakage, 2 cases of intervertebral disc leakage, and 1 case of canal venous leakage, but there was no other complications. The anterior height of affected vertebrae were significantly improved (P < 0.05) from 29.1% ± 6.7% at preoperation to 68.1% ± 7.3% at 3 days after operation and 67.8% ± 5.9% at last follow-up; the VAS scores were significantly decreased (P < 0.05) from 8.11 ± 1.32 at preoperation to 2.14 ± 0.78 at 3 days and 1.97 ± 0.50 at last follow-up; and ODI were significantly decreased (P < 0.05) from 84.6% ± 8.5% to 24.1% ± 9.7% and 23.8% ± 10.2%; but no significant difference was found between at 3 days and at last follow-up (P > 0.05).

Conclusion: Graded infusion of bone cement in unipedicular PVP is a safe and effective procedure for Kummell's disease and this technique could decrease the incidence of bone cement leakage.
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October 2015

Needle puncture in rabbit functional spinal units alters rotational biomechanics.

J Spinal Disord Tech 2015 Apr;28(3):E146-53

Departments of *Physical Medicine and Rehabilitation †Bioengineering ‡Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA §Finance and Trade Hospital of Hunan Province, Tianxin, Changsha ∥The First Affiliated Hospital of University of South China, Xiangtan, Hunan, China.

Study Design: An in vitro biomechanical study for rabbit lumbar functional spinal units (FSUs) using a robot-based spine testing system.

Objective: To elucidate the effect of annular puncture with a 16 G needle on mechanical properties in flexion/extension, axial rotation, and lateral bending.

Summary Of Background Data: Needle puncture of the intervertebral disk has been shown to alter mechanical properties of the disk in compression, torsion, and bending. The effect of needle puncture in FSUs, where intact spinal ligaments and facet joints may mitigate or amplify these changes in the disk, on spinal motion segment stability subject to physiological rotations remains unknown.

Methods: Rabbit FSUs were tested using a robot testing system whose force/moment and position precision were assessed to demonstrate system capability. Flexibility testing methods were developed by load-to-failure testing in flexion/extension, axial rotation, and lateral bending. Subsequent testing methods were used to examine a 16 G needle disk puncture and No. 11 blade disk stab (positive control for mechanical disruption). Flexibility testing was used to assess segmental range-of-motion (degrees), neutral zone stiffness (N m/degrees) and width (degrees and N m), and elastic zone stiffness before and after annular injury.

Results: The robot-based system was capable of performing flexibility testing on FSUs-mean precision of force/moment measurements and robot system movements were <3% and 1%, respectively, of moment-rotation target values. Flexibility moment targets were 0.3 N m for flexion and axial rotation and 0.15 N m for extension and lateral bending. Needle puncture caused significant (P<0.05) changes only in flexion/extension range-of-motion and neutral zone stiffness and width (N m) compared with preintervention. No. 11 blade-stab significantly increased range-of-motion in all motions, decreased neutral zone stiffness and width (N m) in flexion/extension, and increased elastic zone stiffness in flexion and lateral bending.

Conclusions: These findings suggest that disk puncture and stab can destabilize FSUs in primary rotations.
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April 2015

External spinal skeletal fixation combination with percutaneous injury vertebra bone grafting in the treatment of thoracolumbar fractures.

Spine (Phila Pa 1976) 2011 Apr;36(9):E606-11

Spinal Department, First Affiliated Hospital of University of South China, Hengyang city, Hunan, China.

Study Design: A technical report of thoracolumbar fractures managed by percutaneous external pedicular fixation and intracorporeal bone grafting.

Objective: To develop a new technique by combining simplified percutaneous external pedicular fixator with intracorporeal bone grafting to treat thoracolumbar fractures and assess its technical safety and clinical efficacy.

Summary Of Background Data: For surgical treatment of thoracolumbar fractures, the classical techniques are beneficial in decompression, restoration, fixation, and graft fusion, but they are also hugely invasive procedures. The earlier external spinal fixation procedures are good at indirect restoration, decompression, and elastic fixation of spinal fracture. However, they are limited by remains of a large external frame and inability of vertebral reconstruct. Therefore, the minimally invasive techniques combining simplified percutaneous external pedicular fixation and intracorporeal bone grafting might be a useful alternative.

Methods: There were 50 consecutive patients who had thoracolumbar fractures with or without associated incomplete neurologic deficit. They underwent percutaneous external pedicle fixation and intracorporeal bone grafting surgery within 7 days of admission, had their implants removed after 3 months, and were prospectively followed for at least 12 months. American Spine Injury Association grading, spinal canal encroachment, spinal Cobb angle, and vertebral body height were calculated before and after surgery to assess clinical outcome.

Results: A minimum of 12-month follow-up was achieved in 50 patients. The average operative time was 90 minutes (range, 50-160 minutes). The mean bone graft volume was 4.8 cm (range, 3.2-10.6 cm). The intraoperative mean blood loss was 100 mL (range, 50-180 mL). Forty-two patients all had at least one American Spine Injury Association grade neurologic improvement on final follow-up observation; there were no surgery-related complications. The mean anterior height of vertebral body was 53.2% (range 25%-78%) before surgery, 93.6% (range 78%-104%) after surgery, and 94% (range 79%-103%) at final follow-up. The preoperative Cobb angle of the primary curve averaged 30.7° (range 8°-67°), and corrected to 4.5° (range 0°-12.0°) immediately after surgery, There were statistically significant (P < 0.01) among them before and after operation. There was no instrumentation failure or measurable loss of sagittal curve and vertebral height correction in any cases.

Conclusion: The new technique by combination of percutaneous external transpedicular fixation and transpedicular bone grafting is a feasible, safe, useful, efficient, and minimally invasive method to treat thoracolumbar fractures. It is a reasonable alternative method to other minimally invasive techniques of surgical management of the thoracolumbar fractures.
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April 2011

Percutaneous endoscopic lumbar discectomy and interbody fusion with B-Twin expandable spinal spacer.

Arch Orthop Trauma Surg 2011 Jun 16;131(6):791-6. Epub 2010 Dec 16.

Department of Spinal Surgery, 1st Affiliated Hospital, University of South China, 69 Chuanshan Road, Hengyang 412001, Hunan, People's Republic of China.

Background: Posterior lumbar interbody fusion (PLIF) is biomechanically sound as it ablates the degenerated disc, restores the intervertebral height, relieves foraminal stenosis, and positions the bone graft along the weight-bearing axis. But this conventional procedure also results in significant traction on the dural sac and the cauda equina and is thereby a potential source of neurologic damage. Therefore, we performed a minimally invasive technique: percutaneous endoscopic discectomy and interbody fusion (PEDIF) with B-Twin expandable spinal spacer (B-twin ESS) to treat symptomatic lumbar degenerative disc disease and explored the clinical outcome.

Methods: From June 2004 to December 2006, 43 consecutive patients with symptomatic lumbar degenerative disc disease were included in this study. There were 28 males and 15 females, with average age of 47 years (range 26-63). Following a routine micro-endoscopic discectomy or percutaneous nucleotomy, endplate curettage was meticulously carried out. The intervertebral space was packed with autograft cancellous bone cut from lumbar delivered through a 5-mm diameter funnel. The B-twin ESS was introduced into the intervertebral space and then expanded. Both stages were monitored by C-arm fluoroscopy.

Results: The mean operative time was 110 ± 36 min (80-150). The mean blood loss was 350 ± 68 ml (210-700). The mean length of hospitalization was 6.6 ± 2.9 days (3-10). All patients were evaluated in follow-up of 12-30 months (mean 18). According to radiological evidence of fusion on dynamic X-ray plain film, 31 cases (72.1%) achieved bone graft fusion after 6 months postoperatively; at the final follow-up, union of the bone graft has been established in all but one patient (97.7%). The subsidence degree of the B-twin ESS was 20-30% in 2 cases and in rest of the cases less than 10%. According to the modified criteria of Chinese Orthopaedic Association, excellent in 31 cases, good in 8 cases, fair in 3 cases, poor in 1 case, and the rate of excellent and good cases was 91%.

Conclusion: The PEDIF technique provided an option for percutaneous interbody fusion similar to that in open surgery while minimizing destruction to adjacent tissues. This technique was safe and exhibited a trend toward decreased intraoperative blood loss, length of stay and the risk of neurological complications.
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June 2011

Full-endoscopic technique for anterior cervical discectomy and interbody fusion: 5-year follow-up results of 67 cases.

Eur Spine J 2011 Jun 11;20(6):899-904. Epub 2010 Dec 11.

Department of Spinal Surgery, 1st Affiliated Hospital, University of South China, Hengyang 412001, Hunan, People's Republic of China.

With minimally invasive technique becoming more popular, endoscopic operations such as arthroscopy or laparoscopy have become the standard of care in several other areas. In this study, we evaluated the 5-year follow-up outcomes of anterior cervical (Ahn et al. in Photomed Laser Surg 23:362-368, 2005) discectomy and interbody fusion (ACDF) performed via endoscopic approach. Sixty-seven patients who underwent anterior cervical discectomy and cage fusion performed using endoscopic technique were followed for at least 5 years. We reviewed the clinical and radiographic records of these patients. The postoperative radiographic measures accessed were the anterior intervertebral height (AIH) and the lordosis angle (LDA). Clinical outcomes were determined using the previously validated Japanese Orthopaedic Association (JOA) and the pain visual analog scale (VAS). Patients included had a minimal follow-up period of 5 years and based on the outcomes criteria (JOA, VAS), 86.6% of patients reported excellent or good results. The AIH increased on average 18.7% of the original height (p < 0.01), and the LDA were more physiologic at final follow-up. Of the 67 cases, there was no segmental instability, and the bone fusion rate was 100%. One patient required revision open ACDF due to adjacent segment disc herniation 6 years postoperatively. There were no intraoperative complications, dysphasia or esophageal injury in this study group. It indicated endoscopic technique for ACDF can obtain satisfactory results in patients with cervical disc herniation, cervical myelopathy, or radiculopathy. Compared with a traditional approach, this technique may be associated with less morbidity while improving cosmesis and postoperative recovery. Prospective randomized control trials are needed to directly compare these two procedures.
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June 2011