BACKGROUND: Spine has a variety of morphological structures and complicated adjacent location, so the surgery to treat spinal abnormality is a difficult. Three-dimensional (3D) printing technology can transform 3D digital model into physical model, which has been widely used in the field of medicine, even popularized gradually in spine surgery. OBJECTIVE: To summarize the application and status of 3D printing technology in spine surgery, and to make aprospect. METHODS: The first author retrieved CNKI, Baidu Xueshu, Google Scholar, WanFang and PubMed databases for the articles published from 2010 to 2016 using the keywords of 3D printing technology, spine surgery, navigation template,spine physical model, pedicle screw, individualized implants, clinical teaching in Chinese and English, respectively.Finally 29 eligible literatures were enrolled for further analysis in accordance with the inclusion and exclusion criteria.RESULTS AND CONCLUSION: 3D printing technology has been extensively applied in spine surgery, and shows rapid development in preoperative diagnosis, intraoperative navigation, communication, teaching, graft production, implant customization, bone tissue engineering and other aspects. With the development of society, and medical imaging, 3D printing technology will be more promising in the field of medicine, especially in spine surgery

[Objective]To investigate the late results of pedicle screw system and cage fixation for lumbar broken isthmus spondylolisthesis.[Method]Totally 86 patients with broken isthmus spondylolisthesis were collected and analyzed from October 1996 to October 2002,they were all reduced and fixed with pedicle screw system and cage.Group 1,62 patients were put one cage in the interbody at an angle of 45 degree from posterior to anterior,while Group 2,24 patients were put two cages in the interbody vertically from posterior to anterior.The height of interbody and the most proximal interbody' s height were measured,the rate was calculated.These rate were acquired preoperatively,2 weeks postoperatively and follow-up period respectively.[Result]The follow-up period was 24~96 months,averaged 35 months.The excellent and good rates were 80.23 per cent,according to Nakai standard.Ninteen patients with one degree spondylolisthesis were reduced anatomically after surgery.Fifty-one patients with two degree spondylolisthesis were reduced anatomically except 5 patients with one degree spondylolisthesis left.Sixteen patients with three degree spondylolisthesis were reduced anatomically except 4 patients with one degree spondylolisthesis left.There were loss of spondylolisthesis reduction at follow-up period comparing with 2 weeks postoperatively in two groups.However there was no statistical significance between the two groups.[Conclusion]Lumbar spondylolisthesis should be treated with pedicle screw system and cage,which may decrease the complications such as broken screw and spondylolisthesis recurrency postoperatively.One piece of cage is enough to make interbody stable.It is also an ideal procedure for lumbar spondylolisthesis.

[Objective] To evaluate the efficiency of Halovest external immobilization on the treatment of traumatic cervical fracture or dislocation.[Method]From February 1997 to July 2005,129 patients with cervical fracture or dislocation were treated in our hospital;all the patients were divided into two groups randomly.First group: 70 patients were treated with Halo-vest traction,among them 31 patients were treated with Halo vest combined jacket orthosis;others were treated with Halo vests and surgery(anterior route approach 18 cases,posterior route approach 17 cases,4 patients operated by anterior and posterior approach).The second group: 59 patients were treated with skull traction.Among them 13 patients were treated with skull traction and orthosis,others were treated with skull traction and surgery(anterior route approach 22 cases,posterior route approach 20 cases,4 patients operated by anterior and posterior approach).[Result]All the patients were followed 6~48 months(average 12 months).There was no statistical significance in two groups with reduction of upper cervical spine fracture and dislocation.However on the reduction of lower cervical injury groups,the prognosis with Halo-vest is significantly better than the other group.And the time for bed rest was much less than the skull traction.All the patients' spinal cord function improved obviously after treatment.[Conclusion]Halo-vest external fixation is an easy and effective way to treat cervical injuries.It can improve the reduction of the cervical injuries and it's capability of reduction and maintenance are much better than skull traction.

Intramedullary signal intensity (ISI) changes in morphology and extent of T2-weighted (T2W) in preopera?tive cervical magnetic resonance (MR) images was thought to be indicative to the prognosis of cervical spondylotic myelopa?thy (CSM) in recent years. However, the significance of ISI changes in predicting CSM prognosis remains controversial. Lack of satisfied evaluating approch of ISI on magnetic resonance imaging (MRI) is the main drawback. Identification of the type of T2WI ISI on preoperative MR imaging could give important information in predicting surgical outcome of patients with CSM. Currently, consensus is reached that preoperative multi-segmental T2WI ISI or sharp T2WI ISI indicate a worse prognosis for patients with CSM compared with regression of T2WI ISI. The literatures that link magnetic resonance imaging signal changes with prognosis of surgery to correct cervical spondylotic myelopathy are reviewed. The correlation of pathological changes and radiological performance of intramedullary signal intensity with prognosis of CSM are summarized to understand the significance of T2WI ISI on prognosis of surgical outcome.

Objective To study the influence of spinal instability after lamina decompression in symptoms and progno?sis. Methods The 76 patients were followed up for a minimum of 4 more years. The patients were divided into instability group (n=27) and non-instability (n=49) group according to the X-ray result of the final follow-up. The visual analogue scale (VAS) score, JOA score and improvement rate were compared between two groups at preoperation, 3-month after operation and the final follow-up. Results There were no significant differences in gender, age and mean follow-up time between two groups. There were no significant differences in VAS and JOA scores before surgery, 3-month after surgery and final follow-up between two groups. Postoperative VAS score decreased and JOA score increased with the increase in follow-up time (P<0.05). There were no significant differences in improvement rate [(80.0±8.8)%vs (83.6±11.7)%] and improvement ratio [81.48%(22/27) vs 61.22%(30/49)] between two groups (P > 0.05). Conclusion Although some patients show instability even with lumbar spondylolisthesis after lamina decompression on radiograph,which is no correlation with improvement of symptoms. With appropriate indications, lamina decompression is a simple and effective surgical method,which also retains the spinal movement function.

10.3969/j.issn.2095-4344.2013.24.017

Objective To evaluate and compare the presence of the nerve root sedimentation sign in patients with lumbar spondylolisthesis (LS) and lumbar disc herniation(LDH). Methods One hundred and fifty-one patients with degen?erative lumbar spinal disease treated by surgery from July 2012 to March 2014 were reviewed retrospectively in Tianjin Hos?pital. All the patients were divided into two groups:LS group (48 cases) and LDH group (103 cases). The clinical outcomes were evaluated by Japanese Orthopedic Association (JOA). The probability of positive sedimentation sign was compared be?tween LS group and LDH group. Correlation between the JOA score and nerve root sedimentation sign were analysed in two groups. Results There was no statistical difference in JOA score between LS group and LDH group (15.83±3.57 vs 16.76± 3.10, t=1.624, P=0.107). A positive sedimentation sign was identified in 39 patients in the LS group (81.25%) but in 65 pa?tients in the LDH group (63.11%). The difference between LS group and LDH group was statistically significant(χ2=5.028, P=0.031). In LS group, JOA scores of patients with positive nerve root sedimentation sign were lower than those of patients with negative nerve root sedimentation sign(15.33±3.50 vs 18.00±3.20, t=2.092,P=0.042);but in LDH group, there was no statistical difference in JOA scores of patients between positive nerve root sedimentation sign and negative nerve root sedi?mentation sign (16.40±3.13 vs 17.37±2.99, t=1.539, P=0.127). Conclusion A positive sedimentation sign also occurs in pa?tients with LDH, but positive nerve root sedimentation sign are more likely to appear in patients with lumbar spondylolisthe?sis who have worse clinical symptoms.

Objective To analyze the clinical results and early complications of corpectomy and reconstruction with titanium mesh cage implantation and pedicle screw fixation via a single posterior approach for severe thoracic and lumbar fractures.Methods Forty-four patients treated by reconstruction with titanium mesh cage implantation and pedicle screw fixation via a single posterior were studied retrospectively.There were 35 males and 9 females,with an average age of 37.3 years(range,19-66 years).The injury segments include 1 case at T11,5 cases at T12,20 cases at L1,11 cases at L2,5 cases at L3 and 2 cases at L4.According to AO classification,there were 24 cases of A3,17 cases of B1 and B2,and 3 cases of C1.According to ASIA,there were 10 cases of grade A,17 cases of grade B,10 cases of grade C and 7 cases of grade D.The neurologic function and effectiveness of correction of preoperative,immediate postoperative and 2years follow-up were compared,and the clinical outcome and early complications were analyzed.Results The follow-up time was 24 to 58 months,mean 38.9 months.At the time of 2 years postoperation,43 cases of incomplete neurologic deficit had improved 1 or 2 ASIA grades except 1 case of grade A.The results of decompression and reduction were satisfactory from the postoperative radiographic examinations.The correction maintained well and the implant loosening was not seen in 43 cases(97.7%)at the last follow-up.The com plications include:excessive blood loss(＞1500 ml)in 9 cases,transient nerve root injury in 4,cerebrospinal fluid leakage in 3,instrumentation failure in 1,mesh cage malposition in 3,iatrogenic leaving of free bone granula into the canal in 2,and superficial infection in 1.Conclusion This technique is effective for decompression and fusion,less invasive than combined anteroposterior procedure,and may be another good alternative for the treatment of severe thoracic and lumbar fractures.The early complications are not rare,but most of them are not serious and are relative to techniques.

Objective To explore the causes and risk factors affecting early death in patients with traumatic cervical spinal cord injury (SCI). Methods Clinical data of 553 patients with traumatic cervical SCI were analyzed retrospectively to discuss the related factors affecting early death of patients with traumatic cervical SCI by using univariate analysis and multivariate logistic regression analysis. Results The early mortality of the patients with traumatic cervical SCI was 4.0% ( 22/553 ). The main causes of the early death were respiratory failure in nine patients (40.9%) and electrolyte disorders in five (22.7%). Univariate analysis showed that age, cervical spinal cord injury severity, complications in respiratory, cardiovascular, digestive systems and electrolyte disturbance as well as tracheotomy were considered statistically significant for early death in patients with traumatic cervical SCI ( P < 0, 05 ). Multivariate logistic regression analysis showed that age, cervical SCI severity, complications in respiratory,cardiovascular system and electrolyte disturbance as well as tracheotomy. Conclusion Severe cervical SCI, combined respiratory, cardiovascular system and electrolyte disorder complications as well as tracheotomy are high risk factors for the early death in patients with traumatic cervical SCI.

Objective To observe changes in bone mass and symptom duration in patients with lumbar disc herniation(LDH) and explore the relationship between osteoporosis and clinical features of LDH. Methods 83 LDH patients undergoing surgery were enrolled in the study from November 2008 to September 2009. Before surgery, dual-energy X-ray absorptiometry was used to detect bone mineral density of lumbar spine and hip, and calculate T score. The patients were divided into three groups according to the T score: group A (normal bone mass group, n=27), group B (osteopenia group, n=31) and group C (osteoporosis group, n=25). The differences in the duration of symptoms and pathological types were compared between the groups. The relationship between BMI and lumbar spine T-score was explored. Results There were no significant differences in the pathological types among the three groups. The symptom duration in group C was significantly shorter than in group A (P < 0.05). There was no correlation between BMI and lumbar spine T-score (r=0.20, P=0.070). There was positive correlation between BMI and Hip T-score (r=0.263, P=0.016). Conclusion Osteoporosis may affect the symptom duration of LDH patients. We should attach great importance to patients with osteoporosis and LDH.