[Treatment strategy and curative effect analysis of os odontoideum complicated with atlantoaxial joint dislocation].

OBJECTIVE: To explore the treatment strategy and clinical efficacy for os odontoideum complicated with atlantoaxial dislocation. METHODS: The clinical data of 17 patients with os odontoideum complicated with atlantoaxial dislocation surgically treated from January 2006 to January 2015 were retrospectively analyzed, including 7 males and 10 females, aged 17 to 53 (43.1±11.3) years old;course of disease was 3 to 27(10.2±6.9) months. All patients received cranial traction before operation, 12 of 14 patients with reducible dislocation were treated by posterior atlantoaxial fixation and fusion, and 2 patients with atlantooccipital deformity were treated by posterior occipitocervical fixation and fusion;3 patients with irreducible alantoaxial dislocation were treated by transoral approach decompression combined with posterior atlantoaxial fixation and fusion. The operation time, intraoperative blood loss and perioperative complications were recorded. Visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score were used to evaluate the change of neck pain and neurological function. Atlantoaxial joint fusion rate was evaluated by CT scan. RESULTS: The operation time of posterior fixation and fusion ranged from 86 to 170 (92.2±27.5) min, and the intraoperative blood loss was 200-350 (250.7±65.2) ml. No vertebral artery injury and spinal cord injury were recorded. Among the patients underwent atlantoaxial fixation and fusion, 1 patient with reducible dislocation fixed by C2 laminar screw lost reduction after primary operation, and received anterior release again and finally occipitocervical fusion. All patients were followed up for 15 to 58 (32.0±12.2) months. VAS score was decreased from preoperative 4.2±0.9 to 1.3±0.7 at final follow up and the JOA score was improved from preoperative 11.2±1.2 to 16.9±0.8 at final follow-up. CT scan confirmed that the atlantoaxial or occipitocervical fusion wasgood, and the fusion time was 5 to 9 (6.7±0.6) months. CONCLUSION: Surgical treatment of os odontoideum complicated with atlantoaxial dislocation can achieve satisfactory results, improve the patient's neurological function and improve the quality of life, however the surgical options needs to be individualized.

[Minimally invasive direct lateral approach debridement, interbody bone grafting, and interbody fusion combined with posterior percutaneous pedicle screw fixation for lumbar spinal tuberculosis].

OBJECTIVE: To investigate the clinical efficacy and superiority of direct lateral interbody fusion combined with posterior percutaneous screw fixation in the treatment of lumbar tuberculosis. METHODS: From June 2013 to August 2016, the clinical data of 83 patients with lumbar tuberculosis were retrospectively analyzed, including 55 males and 28 females, aged from 27 to 72 (49.5±13.5) years. These 83 patients were divided into two groups according to different operation methods, 35 cases in group A were treated with direct lateral interbody fusion combined with posterior percutaneous screw fixation;48 cases in group B were treated with anterior traditional extraperitoneal debridement combined with posterior internal fixation. After operation, regular quadruple antituberculosis drugs were continued for 18 months. The operation time, intraoperative blood loss, hospital stay, bone graft fusion time and complications were compared between the two groups. Visual analogue score (VAS) of lumbar pain, Oswestry Disability Index (ODI), sagittal Cobb angle, erythrocyte sedimentation rate (ESR) and C-reactive protein(CRP) values before and after operation were analyzed. RESULTS: The operation was successfully completed in both groups, and the operation mode was not changed during operation. The operation time, intraoperative blood loss and hospital stay were (149.4±13.3) min, (354.3±69.0) ml, (9.4±1.6) d in group A and(116.8±10.0) min, (721.9±172.3) ml, (11.8±1.7) d in group B, respectively, with significant difference between the two groups (P<0.05). The follow up time was (24.2±5.1) months in group A and (24.0±5.0) months in group B, there was no significant difference between two groups (P>0.05). At the follow-up of 4 months after operation, one patient in group A was found to have enlarged psoas major abscess on the contralateral side, and was cured after secondary operation. No sinus formation, cerebrospinal fluid leakage, internal fixation loosening, fracture or distal junction kyphosis were found during follow-up. The fusion time was (5.1±1.6) months in group A and (5.1± 1.7) months in group B, there was no significant difference between two groups (P>0.05). The VAS, ODI score, sagittal Cobb angle, ESR and CRP value of the lesion segment at the last follow-up of the two groups were significantly improved (P<0.05), but there was no significant difference between two groups (P>0.05). CONCLUSION: The two kinds of operation can obtain satisfactory clinical effect. Direct lateral interbody fusion combined with posterior percutaneous screw fixation can reduce intraoperative blood loss and hospital stay, which is conducive to early rehabilitation of patients.

[Nomograma prediction of the surgical treatment in triad of elbow].

OBJECTIVE: To establish an individualized Nomogram prediction model for predicting the postoperative recovery of patients with triad of elbow (TE) by analyzing risk factors of triad of elbow joint. METHODS: From January 2012 to December 2018, 116 patients with TE who met the criteria were collected. The independent risk factors were screened by univariate Logistic regression analysis. The statistically significant risk factors were included in the multivariate Logistic regression model. The R software was used to establish the Nomogram diagram model to predict the postoperative recovery of TE patients. C index was used to verify the discrimination, Calibration plot of the model, and the decision curve (decision curve analysis, DCA) to verify the net clinical benefit rate of the model. RESULTS: Forty-four of the 116 patients with TE developed symptoms after operation, with an incidence of 37.93%. Age (OR=1.930, 95% CI 1.418 to 2.764), work (OR=6.153, 95%CI 1.466 to 31.362), smoking(OR=4.463, 95%CI 1.041 to 2.291), the Mason of radial head(OR=1.348, 95%CI 2.309 to 9.348), the Regan-Morrey of coronal process (OR=4.424, 95%CI 1.751 to 2.426) and postoperative elbow immobilization time(OR=7.665, 95%CI 1.056 to 5.100) were independent risk factors for postoperative recovery of TE (P<0.05). The C-index of Nomogram plot was 0.716. Calibration plot showed that the predictive model was consistent, and the DCA curve showed satisfactory clinical net benefit. CONCLUSION: The Nomogram for predicting postoperative results of TE patients based on six independent risk factors:age, work, smoking, Mason classification of radial head, Regan-Morrey classification of coronal process and immobilization time of elbow joint after operation, has good distinguishing capacity and consistency. Thepredictive model could help clinicians to identify high risk population and establish appropriate intervention strategies.

[Comparison of the effects of injured vertebra pedicle fixation combined with vertebroplasty and vertebra pedicle screw fixation combined with vertebroplasty in the treatment of osteoporotic thoracolumbar burst fractures].

OBJECTIVE: To assess the curative effects of injured vertebra pedicle fixation combined with vertebroplasty and short-segment pedicle screw fixation combined with vertebroplasty in treatment of osteoporotic thoracolumbar burst fractures. METHODS: Seventy patients with osteoporotic thoracolumbar burst fractures who met the inclusion criteria were collected in the study from January 2015 to December 2017. Among them, 35 patients were treated with injured vertebra pedicle fixation combined with vertebroplasty (group A), including 20 males and 15 females, aged from 55 to 74 years with an average of (64.03± 7.82) years. Twenty-six cases were type A3 and 9 cases were type A4 according to the AO typing;another 35 patients were treated with short segment pedicle screw fixation combined with vertebroplasty (group B), including 18 males and 17 females, aged from 54 to 72 years with an average of (62.78±6.40) years. Twenty-eight cases were type A3 and 7 cases were type A4 according to AO typing. Operation length, intraoperative bleeding volume, complication, imaging parameters and clinical effects were compared between the two groups. RESULTS: All the patients were followed up for at least 12 months. There were no significant differences in gender, age, injury site, preoperative VAS, Cobb angle, and injured vertebral height before surgery. There were no significant differences in operation length, intraoperative bleeding volume between two groups. In terms of VAS scores before surgery, 1 week after surgery, and at the final follow up, group A was 5.5 ±2.5, 1.8 ±0.8, 0.9 ±0.4, group B was 5.4 ± 2.3, 1.7±0.6, 1.2±1.8, respectively;injured vertebral height was (40.4±8.8)%, (92.0±4.9)%, (87.1±3.8)% in group A, and (41.2±6.6)%, (93.2±4.6)%, (80.0±4.3)% in group B;Cobb angle was (18.4±6.9) °, (2.8±2.2) °, (4.2±2.6) ° in group A, and (16.8±7.2) °, (2.7±2.5) °, (6.0±2.4) ° in group B. There were significant differences in the 3 parameters above before the operation and at the final follow up in all groups (P<0.05). There were significant differences in the Cobb angle and injured vertebral height between 1 week after operation and at the final follow up (P<0.05). At the final follow up, injured vertebral height in group A was obviously better than that in group B (P<0.05). Internal fixation failure occurred in 2 cases from the group A, and occurred in 4 cases from the group B. There were no neurological complications in both groups. CONCLUSION: For osteoporotic thoracolumbar vertebral burst fractures, injured vertebra pedicle fixation combined with vertebroplasty and vertebra pedicle screw fixation combined with vertebroplasty can achieve good clinical effects. However, injured vertebra pedicle fixation combined with vertebroplasty is better at maintaining postoperative vertebral height and sagittal arrangement, and reducing internal fixation related complications. The treatment strategy is worthy of application and promotion.

Missed manubriosternal dislocation in patient with thoracolumbar fracture, a case report.

BACKGROUND: Spine fractures combined with sternal injury are most commonly occur in the thoracic region. Lower cervical and thoracolumbar injuries have also been reported, especially for the patients with manubriosternal dislocation. The type of spine injury is easily recognized in initial presentation, but we may miss the sternal fracture and manubriosternal dislocation. CASE PRESENTATION: A 23-year-old male patient complained with chest, right ankle, and lumbar pain after a fall at ground level, with diagnosis of right distal tibial fracture, sternal fracture, calcaneus fracture, and L2 vertebral fracture. However, neurologically he was completely normal. He underwent the operation for his lower extremity and spine, but we missed his manubriosternal dislocation after discharged. After one month, he came to the clinic with complained of chest pain, the imaging exams showed anterior dislocation of manubriosternal joint. We chose conservative treatment for manubriosternal dislocation. He was followed up at monthly intervals and radiographs along with computerized tomography showed satisfactory in fracture healing of lumber and the sternal fracture. However, the manubriosternal dislocation was malunioned. The patient had appearance deformity of the manubriosternal joint. CONCLUSION: This case supports the concept of the existence and clinical relevance of the thoracic cage theory, the thoracolumbar vertebrae should also be included in the thoracic cage theory.

[One stage temporary atlantoaxial segmental fixation and reduction for Grauer type IIB dens fractures in teenagers].

OBJECTIVE: To assess the clinical results of one stage temporary atlantoaxial segmental fixation and reduction for Grauer type IIB dens fractures in teenagers. METHODS: From February 2009 to April 2015, 19 teenagers with Grauer type IIB dens fractures not amenable to anteiror screw fixation were enrolled and treated using one stage temporary atlantoaxial segmental fixation and reduction without fusion. There were 14 males and 5 females, aged from 14 to 32 years with an average of (24.6±5.0 ) years. The internal fixation was removed after bone healing confirmed by CT scan. At the last follow-up (at least 1 year after internal fixation removal), dynamic CT was used to assess the atlantoaxial rotation activity. Visual analogue scale (VAS) was recorded before the first operation, before the second operation (removal of internal fixation) and at the last follow-up. Neck Disability Index(NDI) was used to evaluate the efficacy before the second operation (removal of internal fixation) and the last follow-up. RESULTS: After operation, 2 patients developed the symptoms of occipital nerve stimulation such as numbness and pain in the occipitocervical region, and were treated with drugs such as dehydration and neurotrophic drugs, and the symptoms were relieved after 1 to 2 months. All the internal fixations were removed and all the patients were followed up more than 1 year, with time ranging from 18 to 25 months and an average of (21.47±2.41) months. The time of bone fusion after operation was 6 to 10 months with the mean of(8.21±1.27) months. Secondary surgical removal of internal fixation were performed immediately after fracture healing without internal fixation failure. The symptoms of neck pain improved significantly after operation, VAS score decreased from 6.74±0.65 before operation to 0.42±0.51 at the last follow-up after the second operation (removal of internal fixation), with statistically significant differences(P<0.01). The NDI value decreased from (10.58±2.04)% before the second operation (removal of internal fixation) to (3.79±2.23)% at the last follow-up after the second operation (removal of internal fixation), with statistically significant difference(P<0.01). At the last follow-up after the second operation (removal of internal fixation), dynamic CT showed that the unilateral rotation of the atlantoaxial spine reached (15.73±5.57)° to the left, (15.55±5.78)° to the right, and the overall rotation of the atlantoaxial spine was (31.28±10.71)°. CONCLUSIONS: One stage temporary atlantoaxial segmental fixation and reduction for the treatment of Grauer type IIB dens fractures not amenable to anteiror screw fixation in teenagers can avoid the loss of atlantoaxial rotation function caused by atlantoaxial fusion, and to some extent retain the rotation activity of atlanto-axial joint.

[Treatment of senile spinal tuberculosis with posterior percutaneous pedicle screw fixation combined with local percutaneous endoscopic debridement].

OBJECTIVE: To explore the short-term efficacy of posterior percutaneous screw fixation combined with local percutaneous endoscopic debridement in treating senile spinal tuberculosis. METHODS: The clinical data of 19 senile patients with spinal tuberculosis underwent surgical treatment from January 2015 to September 2016 were retrospectively analyzed. There were 13 males and 6 females, aged from 60 to 73 years old with an average of (66.2±4.0) years. All patients have been diagnosed with spinal tuberculosis prior to hospitalization with abscess, dead bone formation but no sinus, neurological symptoms, open surgical indications. All patients were treated with posterior percutaneous screw fixation combined with local percutaneous endoscopic debridement, and were given appropriate chemotherapy for 3 weeks preoperatively. Pre-and post-operative visual analogue score (VAS), Oswestry Disability Index (ODI), sagittal Cobb angle of lesion segment, erythrocyte sedimentation rate(ESR), C-reactive protein(CRP) were analyzed. RESULTS: All the 19 patients successfully completed the operation and passed through the perioperative period safely. The operation method was unchanged during the operation. The average operation time was (153.2±14.0) min. Except for 1 patients who had delayed incision healing, other patients healed at I stage within 2 weeks after operation. All patients were followed up for 15 to 26 months with an average of (19.6±3.2) months.VAS, ODI, sagittal Cobb angle of lesion segment, ESR, CRP were decreased from preoperative(5.9±1.1) points, (80.9±4.0)%, (30.8±5.5)°, (79.6±14.4) mm/h, (56.9±9.5) mg/L to(1.8±0.9) points, (66.4±5.4)%, (15.9±2.5)°, (20.4±4.6) mg/L, (32.0±8.1) mm/h at final follow-up(P<0.05). CONCLUSIONS: Senile spinal tuberculosis have more complications and poor general body condition. Posterior percutaneous pedicle screw fixation combined with local percutaneous endoscopic debridement in treating the patients can reduce trauma, got satisfactory effect.

[Case-control study of pedicle screw fixation combined with vertebroplasty and injured vertebra pedicle fixation in treatment of osteoporotic thoracolumbar burst fractures].

OBJECTIVE: To compare the curative effect of short-segment pedicle screw fixation combined with vertebroplasty and injured vertebra pedicle fixation in treating osteoporotic thoracolumbar burst fractures. METHODS: A retrospective study was performed for 52 patients with thoracolumbar burst fractures from August 2010 to August 2015. Among them, 27 patients(group A) were treated with short-segment pedicle screw fixation combined with vertebroplasty, including 17 males and 10 females, aged from 54 to 68 years old with an average of(61.01±5.41) years, 16 cases were type A3 and 11 cases were type A4 according the new AO typing. Other 25 patients (group B) were treated with short-segment pedicle screw fixation combined with injured vertebra pedicle fixation, including 12 males and 13 females, aged from 55 to 66 years old with an average of (59.28±6.12) years, 18 cases were type A3 and 7 cases were type A4 according the new AO typing. Operation time, intraoperative bleeding volume, complication, image data and clinical effect were compared between two groups. RESULTS: All the patients were followed up for 12 to 15 months with an average of (12.4±2.1)months. There was no significant difference in general data(including gender, age, injured site, preoperative VAS score, Cobb angle, injured vertebral anterior border height) between two groups. There was no significant differences in operation time, intraoperative bleeding volume between two groups. Preoperative, one week after operation and final follow-up, VAS scores were 5.2±0.5, 1.2±0.2, 0.8±0.1 respectively in group A and 5.0±0.6, 2.5±0.4, 1.3±0.2 in group B; injured vertebral anterior border height were (49.4±6.8)%, ( 94.5±1.2)%, ( 94.1±3.7)% respectively in group A and (48.2±7.0)%, ( 94.3±4.1)%, ( 90.0±2.3)% in group B;Cobb angles were (20.4±5.2) °, (2.5±1.8) °, (4.4±1.7)° respectively in group A and (19.8±6.8)°, (2.4±1.7)°, (7.0±1.2)° in group B. At final follow-up, VAS, Cobb angle, injured vertebral anterior border height in two groups were obviously improved(P<0.05). Postoperative at 1 week and final follow-up, VAS score of group A was lower than that of group B(P<0.05);and there was no significant difference in Cobb angle between two groups(P>0.05); there was significant difference in injured vertebral anterior border height between two groups(P<0.05). The complication of internal fixation failure had 1 case in group A and 4 cases in group B. CONCLUSIONS: For the treatment of single osteoporotic thoracolumbar burst fractures, short-segment pedicle screw fixation combined with vertebroplasty is better than combined with injured vertebra pedicle fixation in clinical effect, it can relieve pain, maintain injured vertebral height and sagittal alinement, reduce the complications associated with internal fixation, and be worth spread in clinic.

Complications and Prevention Strategies of Oblique Lateral Interbody Fusion Technique.

OBJECTIVE: To analyze the early complications and causes of oblique lateral interbody fusion, and put forward preventive measures. METHODS: There were 235 patients (79 males and 156 females) analyzed in our study from October 2014 to May 2017. The average age was 61.9 ± 0.21 years (from 32 to 83 years). Ninety-one cases were treated with oblique lateral interbody fusion (OLIF) alone (OLIF alone group) and 144 with OLIF combined with posterior pedicle screw fixation through the intermuscular space approach (OLIF combined group). In addition, 137/144 cases in the combined group were primarily treated by posterior pedicle screw fixation, while the treatments were postponed in 7 cases. There were 190 cases of single fusion segments, 11 of 2 segments, 21 of 3 segments, and 13 of 4 segments. Intraoperative and postoperative complications were observed. RESULTS: Average follow-up time was 15.6 ± 7.5 months (ranged from 6 to 36 months). Five cases were lost to follow-up (2 cases from the OLIF alone group and 3 cases from the OLIF combined group). There were 7 cases of vascular injury, 22 cases of endplate damage, 2 cases of vertebral body fracture, 11 cases of nerve injury, 18 cases of cage sedimentation or cage transverse shifting, 3 cases of iliac crest pain, 1 case of right psoas major hematoma, 2 cases of incomplete ileus, 1 case of acute heart failure, 1 case of cerebral infarction, 3 case of left lower abdominal pain, 9 cases of transient psoas weakness, 3 cases of transient quadriceps weakness, and 8 cases of reoperation. The complication incidence was 32.34%. Thirty-three cases occurred in the OLIF alone group, with a rate of 36.26%, and 43 cases in the group of OLIF combined posterior pedicle screw fixation, with a rate of 29.86%. Fifty-seven cases occurred in single-segment fusion, with a rate of 30.0% (57/190), 4 cases occurred in two-segment fusion, with a rate of 36.36% (4/11), 9 cases occurred in three-segment fusion, with a rate of 42.86% (9/21), and 6 cases occurred in four-segment fusion, with a rate of 46.15% (6/13). CONCLUSION: In summary, OLIF is a relatively safe and very effective technique for minimally invasive lumbar fusion. Nonetheless, it should be noted that OLIF carries the risk of complications, especially in the early stage of development.

Surgical treatment of compressive spinal hemangioma : A case series of three patients and literature review.

PURPOSE: In this article we describe the treatment of compressive vertebral hemangioma. METHODS: Our case series comprised three patients with aggressive hemangioma. We performed a combination of posterior decompression and vertebroplasty for the two patients with a sacral hemangioma and a thoracic hemangioma, and en bloc resection for the third patient, who also had a thoracic lesion. RESULTS: Surgical intervention is indicated in cases of rapidly progressive tumors or severe myelopathy. All three patients had good clinical results. The follow-up period ranged from 8 to 56 months. The mean blood loss was around 700 ml, and mean surgical time was 2.1 h. Blood loss for the en bloc procedure was around 1,200 ml, and surgical time was 2.3 h. CONCLUSION: A combination of posterior decompression, vertebroplasty, and posterior fixation for aggressive hemangioma can reduce blood loss during surgery. For patients with hemangioma and with incomplete paralysis, total en bloc spondylectomy should be considered. Adjuvant radiotherapy can reduce the recurrence of cavernous vertebral hemangiomas.

[Posterior osteotomy and long-segment internal fixation for the treatment of senile thoracolumbar kyphotic deformity].

OBJECTIVE: To explore the therapeutic effects of posterior osteotomy and long-segment internal fixation in the treatment of senile thoracolumbar kyphotic deformity and provide the reference for operative treatment. METHODS: From April 2007 to April 2010, 19 older patients with thoracolumbar kyphotic deformity were respectively analyzed. There were 12 males and 7 females with an average age of 62 years (ranged, 58 to 74 years). Among patients, 11 cases were old fracture, 3 cases were ankylosing spondylitis, and 5 cases were old spinal tuberculosis. According to preoperative Frankel classification, 12 cases were grade E, 4 cases were grade D, 2 cases were C and 1 case was grade B. All patients were treated by posterior osteotomy and long-segment internal fixation and followed up above 1 year. VAS score preoperative, 2 weeks and 1 year after operation, Cobb's angle,n erve function and complication were observed. RESULTS: VAS score preoperative, 2 weeks and 1 year after operation separately was (7.0 +/- 1.2),(1.1 +/= .7) and (1.3 +/- .8); while Cobb's angle separately was (44.1 +/- .9), (10.9 +/- .1) and (11.5 +/- .8); there was significant difference in VAS score and Cobb's angle between preoperative and 2 weeks after operation (P < 0.05) w hile no significant difference between 2 weeks and 1 year after operation (P > 0.05). Eighteen cases met the standard of osseous fusion, 1 case occurred nonunion, but not looseness 1 year after operation. Nerve function: 3 cases changed grade E from 4 cases with grade D, 2 cases with grade C changed to grade D, 1 case with grade B changed to grade CONCLUSION: Posterior osteotomy and long-segment internal fixation for the treatment of senile thoracolumbar kyphotic deformity can receive a good short-time effects.

A new technique for anterior cervical pedicle screw implantation.

OBJECTIVE: To introduce and evaluate a new technique, anterior pedicle screw implantation, for anterior cervical reconstruction. METHODS: Seven patients (five men and two women) with an average age of 65 years were included in this group. After carefully preparation, anterior pedicle screws were implanted under fluoroscopy in all patients. The position of the anterior pedicle screws was evaluated three days postoperatively by X-ray and CT imaging. The mean recovery rate as assessed by the Japanese Orthopaedic Association (JOA) score was recorded at final follow-up. RESULTS: A total of fourteen anterior pedicle screws were implanted in our group. The average follow up period was 8 months. The mean JOA score was 12.5 preoperatively and 14.8 postoperatively. The mean improvement in the JOA score was 50.5% at final follow-up. The average local alignment improved from 4.0 of kyphosis preoperatively to 6.5 of lordosis at final follow-up. Early bony union was observed in four cases that were followed up for more than 3 months. There were no serious complications. No "pedicle perforation" was observed in any of the fourteen anterior pedicle screws, whereas one screw exposure occurred. CONCLUSION: Anterior cervical pedicle screw implantation is a feasible method for selected cases. It provides another choice for strong anterior cervical reconstruction.

[Study on the feasibility of posterior thoracic transarticular screw fixation].

OBJECTIVE: To study the feasibility and technical parameters of posterior transarticular screw fixation in the thoracic spine. METHODS: Since September 2009 to December 2009, 20 thoracic cadaveric spines (12 males and 8 females) were dissected. The lateral masses and pedicles were exposed carefully. After the entrance point of transarticular screws was determined, posterior transarticular screws implantation was performed under direct visualization into T(1,2), T(5,6) and T(9,10). Then CT scan was performed. On the CT scan,the angle and length of the transarticular screw trajectory were measured. RESULTS: The thoracic transarticular screw trajectory were caudal tilting in the sagittal plane and lateral tilting in the coronal plane with successful placement. There was little differences between different segmental of thoracic vertebrae of the angle, but without significance (P > 0.5). The average angles of the screws were (52.6 +/- 5.9) degrees caudal tilting in the sagittal plane and (12.4 +/- 2.9)0 lateral tilting in the coronal plane. The average trajectory lengths were (22.5 +/- 1.9) mm. There was significant differences statistically among T(1,2), T(5,6) and T(9,10) (P < 0.01). CONCLUSION: Posterior transarticular screw fixation is feasible. Transarticular screw fixation in the thoracic spine affords an alternative to standard pedicle screw placement for thoracic stabilization.

[Comparison of three techniques of the transarticular screw placement in the lower cervical spine].

OBJECTIVE: To compare three techniques of the transarticular screw placement in the lower cervical spine. METHODS: The techniques of transarticular screw placements used by Takayasu (group A), Dalcanto (group B) and Klekamp (group C) were applied in twenty-four cervical specimens, among which 14 specimens were male and 10 specimens were female, ranging in age from 55 to 80 years, with an average of 68 years. The entry point of Takayasu technique was between the superior and median third of the vertical medial line of the lateral mass with 60 to 80 degrees caudal tilt and 0 degrees lateral tilt. Dalcanto technique started 2 mm caudal to the midpoint of lateral mass with 40 degrees caudal tilt and 20 degrees lateral tilt. Klekamp technique inserted the screws with the starting point being 1 mm medial and 1 mm inferior to the midpoint of the lateral mass with 40 degrees caudal tilt and 20 degrees lateral tilt. The splits of facets, the encroachment of the cervical nerve roots and vertebral arteries, and no-involving facets screws were observed and analyzed. RESULTS: One hundred and ninety-two transarticular screws were implanted on both sides in twenty-four cervical cadavers, sixty-four for each group. There were twenty-five splits of inferior facets in group B, 2 splits in group C and none in group A. No superior facets were found to be broken in all cases. The difference of splits between group B and the other two groups was significant (Chi2AB = 31.07, P < .001; Chi2BC = 24.83, P < 0.01), while there was no statistical difference between group A and C (Chi2AC = 2.03, P > 0.05). Thirty-six screws encroached the vertebral arteries in group A, none in group B and C. There was significant statistical difference between group A and the other two groups (Chi2AB = 50.09, P < 0.01; Chi2AC = 50.09, P < 0.01). Forty anterior branches of lower cervical nerve roots were involved in group A, five in group B and three in group C. There were statistical differences between group A and the other two groups (Chi2AB = 41.98, P < 0.01; Chi2AC = 47-94, P < 0.01), and there was no statistical difference between group B and C. Sixteen posterior branches of lower cervical nerve roots were encroached in group A, 18 in group B and 14 in group C. There was statistical difference among the three groups (Chi2AB = 0.16, P > 0.05; Chi2AC = 0.17, 0.05; Chi2 = BC = 0.67, P >0.0 ). Although all screws went through facets in the study except for 5 in group A, there were no statistical differences between each groups Chi2AB k =3.33, P >0.05; X2A C =3.33, P> 0.05). CONCLUSION: There are high risk of injury of anterior branch of cervical nerve root and vertebral artery if the screws are too long and the Takayasu's technique is used. However, the rate of facet split is high if the Dalcanto's technique is applied. Klekamp's technique is value to be applied.