A multicenter retrospective clinical study on "symptomatic facet of residual bone mass", a rare complication of percutaneous trasforaminal endoscopic discectomy / 中华骨科杂志

Objective Retrospective study and report on cases of "symptomatic facet of residual bone mass" caused by percutaneous transforaminal endoscopic discectomy (PTED),to analysis of its causes and revision strategies.Methods Seven cases of "symptomatic facet of residual bone mass" after PTED were found in six medical centers from July 2015 to November 2017.Weintroduced the course of diagnosis and treatment,to analysis of the causes,clinical features and revision strategies of the rare complication.Results Seven patients came from different medical centers (2 cases in Ningbo No.6 Hospital and 1 case in each of the other medical centers).The average age of the subject is 67.29±9.64 years (range from 57-83 years).Among them there were 1 male and 6 female.PTED was performed for all cases with lumbar disc herniation or stenosis.The operative segments were 1 of L2,3,2 of L3,4,3 of L4,5,1 of L5S1.Symptoms occurred immediately after surgery in all cases except one after a week of operation and another one month later.Two cases were appeared symptom of contralateral irritation,and the rest were aggravated by the original symptoms.Two cerebrospinal fluid leakage caused by bone mass piercing the dural sac.The bone mass compressed the nerve root and caused 1 case of lower limb muscle weakness.Foraminoplasty was performed during PTED in all patients.After CT scan,5 cases of bone mass were found on the same side of operation,and 2 cases were in the contralateral side.The shortest time for revision was 2 days and the longest 3 months.After conservative treatment,the symptoms were relieved in only one case.Revision surgeries were performed for all the other 6 cases,2 with microendoscopic discectomy (MED),1 mobile microendoscopic discectomy (MMED),1 small incision operation,1 PTED and 1 with minimal invasive surgery of transforaminal lumbar intervertebral fusion (MIS-TLIF).The VAS scores of low back pain and leg pain was significantly relieved from 8.67±0.52 to 1.50±0.55.Conclusion FTED may lead to residual bone mass in lumbar foraminoplasty.The penetration of the bone mass block into the spinal canal can cause the compression symptoms of the corresponding segment.The patients showed the corresponding spinal canal stenosis and nerve root irritation symptoms.A revision operation is required to remove the oppressed bone mass to relieve the symptoms as soon as possible if the conservative treatment not effective.

Clinical report of revision surgery after percutaneous transforaminal endoscopic surgery for lumbar stenosis / 中华骨科杂志

Objective To analyze the causes of revision surgery after percutaneous transforaminal endoscopic discectomy (PTED) for lumbar spinal stenosis,and to provide references for indications and operative methods.Methods From January 2015 to October 2017,206,491 and 60 patients of lumbar spinal stenosis were treated with PTED in Tianjin Hospital,Shanxi People's Hospital,Ningbo Sixth Hospital,respectively;among them,4,10 and 4 cases received revision surgery.Another 13 patients of lumbar spinal stenosis were treated with revision surgery due to poor results after PTED in other hospitals.Among 31 cases of reoperation,there were 16 males and 15 females,aged 27-82 years (average,66.2±12.7 years).The lesion segments included 1 case of L3,4,23 cases of L4,5,5 cases of L5S1,1 cases of L3-L5,and 1 cases of L4-S1.Patients were followed up after reoperation from 3 to 24 months (average,12.1 months).The causes of poor result and revision surgery were analyzed according to preoperative,intraoperative and postoperative data.Results All of 757 cases of lumbar spinal stenosis were treated with PTED in three hospitals,of which 18 cases (2.4％) were re-operated.The causes of reoperation included:bone slice displacement in 1 case;nerve injury in 4 cases;lumbar instability in 4 cases;disc protrusion in 10 cases (residual or recurrence);insufficient decompression in 21 cases;planed staging operation in 4 cases with bilateral or two-level stenosis.32 revision surgeries were performed for 31 patients,including PTED in 15 cases,microendoscopic discectomy (MED) in 1 case,mobile MED (MMED) in 5 cases,MMED assisted fusion in 2 cases,transforaminal lumbar interbody fusion (TLIF) in 4 cases,Minimally invasive TLIF (Mis-TLIF) in 2 cases,and open decompression and fusion in 3 cases.All patients experienced relieve of symptoms after revision surgery.At final follow-up,VAS leg pain deceased form 7.1±3.9 before revision surgeries to 1.9±1.2,VAS low back pain decreased form 6.3±3.2 to 1.8±1.3,ODI score decreased from 35％± 14％ to 7.6％±5％.According to the MacNab score,the result was excellent in 11 cases,good in 16 cases,and fair in 4 cases.Conclusion The treatment of lumbar stenosis with PTED has high technical requirements,the indications of PTED for lumbar stenosis should be strictly controlled according to technical conditions,and appropriate operative methods should be chosen according to the specific conditions of the lesions.Insufficient decompression,disc protrusion,lumbar instability and nerve injury are the common causes of reoperation.Suitable indications and proper operation should be selected.

Modified drilling template for placement of cervical anterior transpedicular screws / 中华创伤骨科杂志

Objective To evaluate the accuracy in placement of cervical anterior transpedicular screws (ATPS) under the guidance of our modified drilling template.Methods Eight wet cadaveric specimens of adult cervical spine,4 male and 4 female ones,were used for this experiment.Data of CT thin layer scanning of the cervical specimens in DICOM format were imported into software Mimics 17.0.After 3D models of the cervical vertebrae were reconstructed,the optimal trajectory was designed for ATPS placement in the transparent mode of the 3D models.Normal and our modified drilling templates for ATPS placement were designed and manufactured by 3D printing.The 2 kinds of drilling templates were used to assist ATPS placement onto one cervical vertebra,with laterality randomized.Altogether 64 pieces of ATPS were placed,with 32 ones for each drilling template.Postoperative CT scanning was conducted to evaluate the accuracy in ATPS placement.The 2 kinds of ATPS template were compared in terms of the deviations between actual and ideal trajectories in direction (caudal-angle and extroversive-angle) and position (X and Y axes) of the entry point.Results Our modified drilling template led to one screw penetrating the pedicle cortical bone while the normal drilling template led to 4 screws penetrating the pedicle cortical bone,yielding an accuracy rate of 96.9％ and of 87.5％ respectively.The extroversive-angle deviation (0.72°±0.69°),caudal-angle deviation (0.91°±0.70°),X axis shift (0.53 ±0.40 mm) and Y axis shift (0.54 ±0.42 mm) related to the modified template were all significantly smaller than those related to the normal template (1.16° ± 0.70°,1.49°±0.68°,0.88±0.40mm,1.22±0.42mm,respectively) (P ＜0.05).Conclusion Compared with a normal ATPS template,our modified drilling template for ATPS may be advantageous in better fitness,greater stability,increased accuracy in screw placement,and protection of adjacent discs.

Radiological and anatomical study of posterior occipital condyle screw trajectory / 中华创伤杂志

Objective To investigate the optimal trajectory of posterior occipital condyle screw fixation via radiological and anatomical study.Methods Twelve adult craniocervical junction complete specimens were selected.The length,width and height of occipital condyle and the inclination angle of the longest axis were measured by CT scanning and reconstruction.Subsequently,occipital condyle screws were inserted with reference to CT measurements.After screw fixation,accuracy and safety of the placement of occipital condyle screw were verified by gross observation and CT scanning.Results Preoperative measurements of height and width of the occipital condyles indicated the placement of 4.0 mm bicortical screws was secure.Left vertebral artery horizontal sections of 2 specimens were slightly pressed without damage.CT scanning identified no damage to the inner or outer wall of the occipital condyle and the hypoglossal canal.Trajectory parameters between the right and left sides were slightly different,but no significant difference was observed (P ＞ 0.05).Average screw channel length and inclination angle were (20.8 ±2.6)mm and (37.1 ± 4.7)°respectively.Angle between screw and skull base tangent was observed as (8.5 ± 1.7) °.Distance between screw axis and hypoglossal canal was observed as (3.1 ± 1.1) mm.And the distance averaged (4.6 ± 1.4) mm between occipital condyle screw entry point and skull base and (6.1 ± 1.5) mm between entry point and inside edge of the occipital condyle.Conclusion Occipital condyle can be used as a new alternative fixed point in occipitocervical fusion.

Finite element analysis of biomechanical performance of atlanto-axial bony structure following artificial atlanto-odontoid joint arthroplasty / 中华创伤杂志

Objective To investigate the stress characteristics of atlanto-axial bony structure under conditions of anteflexion,posterior extension,lateral flexion,and rotation after artificial atlanto-odontoid joint arthroplasty using three-dimensional finite element method and to improve the orientation of artificial atlantoodontoid joint from perspective of stress.Methods A three-dimensional finite element model of prosthetic atlanto-odontoid joint arthroplasty was created from CT images of the artificial atlantoodontoid joint and cervical vertebrae using software Mimics,Freeform,and Ansys.Stress characteristics of the model dealt with proneness,posterior extension,lateral flexion,or rotation loads were observed.Biomechanical performance of the bony structure of the model was analyzed and the orientation in improving the prosthesis was discussed.Results Anteflexion loading produced a maximum stress of 0.138 ×l08 N/m2 at the junction of lateral mass and posterior arch of the atlas,and 0.201 × 108 N/m2 at axial nail hole,contact point of plates with the axis,and posterior arch of the axis.Posterior extension loading produced a maximum stress of 0.666 × 107 N/m2 at junction of lateral mass and posterior arch of the atlas and 0.254 × 108 N/m2 at arch of the axis.Besides,stress concentration occurred at atlantoaxis nail hole.Right bending produced a maximum stress of 0.124 × 108 N/m2 at nail hole of right mass of atlas and 0.178 × 108 N/m2 at right contact point of the axis with plates.Right rotation produced a maximum stress of 0.847 × 107 N/m2 at junction of lateral mass and posterior arch of the atlas and 0.170 × 109 N/m2 at contact point of the axis with plates.The finite element model comprised 28 620 nodes and 107 441 units and provided good defining of the structural properties of artificial atlanto-odontoid joint arthroplasty.Under different loading conditions,the stress was mainly distributed in contact point of the vertebral body with plates,nail holes,junction of lateral mass and posterior arch of the atlas,and axial pedicle.Conclusions Prosthetic atlanto-odontoid joint scatters a part of the stress and alters the stress distribution of the atlas and axis from the intact condition.Finite element method can obtain complete analysis of the stress distribution of the artificial atlanto-odontoid joint arthroplasty.

Unstable atlas fractures treated by anterior plate fixation through transoral approach / 中华骨科杂志

Objective To explore the clinical outcomes of anterior plate fixation through transoral approach in the treatment of unstable atlas fractures.Methods From March 2004 to May 2010,20 patients with unstable atlas fractures were treated by anterior plate fixation through transoral approach,including 12 males and 8 females,aged from 23 to 68 years (average,47.7±13.9 years).Of the 20 cases of unstable atlas fractures,4 cases were classified as anterior 1/2 Jefferson fracture,8 cases as 1/2 ring Jefferson fracture,and 8 cases as anterior 3/4 ring Jefferson fracture.The preoperative average VAS scores were 6.0±1.3 points,ranged from 4 to 8 points.Clinical and imaging examinations were performed during follow-up period to evaluate the outcomes.Results All patients were followed up for 12 to 81 months,with an average of 48.5±20.0 months.There were no screw loosing and breakage,no plate displacement,and no spinal cord and vertebral artery injury during operation.A total of 20 plates were placed and all 40 screws were inserted into atlas lateral mass.Computed tomography scans demonstrated 2 screws were placed too close to the vertebral artery canal,but without clinical consequences.The postoperative VAS scores were from 0 to 3 points with an average of 1.3±1.0 points.Static and dynamic films 6 months after surgery demonstrated that fusion was achieved in all cases.Atlantoaxial rotational function was restored satisfactorily.No plate-related complication was observed in all patients in the whole follow-up period.Conclusion Anterior plate fixation through transoral approach is an effective method for management of unstable atlas fractures,which has advantages such as solid bony fusion and low incidence of complication.

Preliminary clinical study of anterior pedicle screw fixation for lower cervical spine injuries / 中华创伤杂志

Objective To investigate the preliminary clinical application of anterior pedicle screws in treatment of the lower cervical spine injuries. Methods The study involved 22 patients with lower cervical spine injuries treated with anterior pedicle screw technique from January 2009 to December 2011.X-ray and CT images of the patients were taken postoperatively to evaluate whether the position,orientation and length of the screws were appropriate and whether there involved pedicle cortex perforation,transverse foramen or spinal canal invasion.MRI was also performed to ascertain the situation of decompression,the formation of epidural hematoma and the degeneration of cervical spinal cord.The improvement of JOA score was compared statistically. Results All the patients were followed up for 3-36 months ( mean,15.5 months).A total of 44 anterior lower cervical screws were implanted and all screws were inserted smoothly.All the patients had bone healing after average 4.5 months,which showed no loosening,prolapse or breakage of the screws or no loosening of the plate.One patient showed hoarseness postoperatively,which was probably due to the long-term distraction of recurrent laryngeal nerve.The symptom disappeared at around three weeks after neurotrophic support.Two patients complained of dysphagia postoperatively,and were informed of keeping a soft diet.The symptom was remarkably alleviated after three months or so.The X-ray films indicated satisfactory position of the implanted screws.Before discharge,the transaxial CT images showed that two screws perforated the medial pedicle cortex ( 1 ° ) and that two screws perforated the lateral cortex (1 °) and affected the medial margin of the transverse foramen.Before discharge,the MRI indicated obvious alleviation of the anterior spinal cord compression in all patients and a small amount of anterior epidural hematoma in four patients,with no obvious spinal cord compression.At 12 months after operation,the MRI showed significant improvement of spinal cord degeneration in three patients.JOA score was increased from preoperative (8.5 ± 0.7) to ( 14.5 ± 0.8 ) before discharge (P ＜0.01 ).JOA score was (15.7 ±0.7) at six months postoperatively,which was significantly improved as compared with that before discharge. Conclusions Anterior pedicle screw fixation is a reliable and safe method for reconstruction of the anterior lower cervical injuries.Surgical indications should be strictly controlled in its clinical application.

Minimally invasive transforaminal lumbar interbody fusion or posterior lumbar interbody fusion in treatment of lumbar degenerative disorder disease / 中华骨科杂志

ObjectiveTo evaluate the clinical effects of transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion(PLIF) using microendoscopic discectomy under X-Tube system in treatment of lumbar degenerative disc diseases.MethodsFrom December 2007 to April 2008,32 patients with low back disorders were treated by microendoscopic discectomy TLIF or PLIF under X-Tube system,including 19 cases in TLIF and 13 in PLIF.Etiologies including lumbar disc herniation combined with segmental instability in 21 cases,and spondylolisthesis in 11 cases.All patients were under regular postoperative follow-up and radiological examination.The clinical functional outcomes were evaluated according to Oswestry disability questionnaire.ResultsThe mean operation time was 120 min(range,90-180),and the average blood loss was 190 ml (range,100-400).There were no complications,such as infection and internal fixation failure.Bony fusion was achieved in all patients.The follow-up was from 14 months to 41 months with 21 months in the average.The average 0swestry scores decreased from preoperative 40.1％±4.1％ to 9.5％±3.7％ three months after the operation.The outcomes of this operation were rated as excellent.ConclusionMicroendoscopic discectomy TLIF or PLIF under X-Tube system in treatment of lumbar degenerative disc diseases has the characteristics of less blood loss,tissue trauma and quick recovery.

Surgical treatment selection for unstable atlas fractures / 中华创伤杂志

Objective To evaluate the clinical effect and safety of the occiput-cervicle or C1-C2 internal fixation and bone graft fusion in treatment of the unstable atlas fracture.Methods A retrospective study was performed in 38 patients with unstable atlas fractures treated by the occiput-cervicle or C1-C2 internal fixation and bone graft fusion from October 2004 to March 2009.Six patients with comminuted atlas fracture combined with instability of the occipito-atlantoid articulations were treated with occiput-C2 fusion(five patients)and with occiput-C3 fusion(one patient).There were seven patients with typical Jefferson fractures,three with semiring fractures,eight with atlas fractures combined with Anderson type Ⅱ odontoid process fractures,three with atlas fractures combined with Hangman's fractures (two patients with Levine and Edwards type Ⅲ Hangman's fractures were treated with occiput-C3 fusion and one patient Levine and Edwards type Ⅱ Hangman's fracture was treated with C1-C2 fusion),three with atlas fracture combined with lower cervicle injury,six with rupture of transverse ligament combined with instability of atlanto-axial joint(Dickman transverse ligament type Ⅰ injury)and two with comminuted fracture of the lateral mass associated with bony avulsion of the medial tubercle and transverse ligament(Dickman transverse ligament type Ⅱ injury).Of all,five patients were treated with occiput-C2 fusion,three treated with occiput-C3 fusion and 30 treated with C1-C2 fusion.Results All the patients were followed up for a range of 12-46 months(average 28 months),which showed improvement of clinical symptoms in some extent postoperatively.The operation time ranged from 80 to 190 min ates(average 135 minates),with intraoperative blood loss for 200-3 300 ml(average 460 ml)and average fluoroscopic time for 60 seconds.There were no neurological deficits,vertebral artery related complications or other complications in all the patients during the surgical operation.No neurological deficit was aggravated after the patient's mobilization with brace three days after operation.The enous plexus of blood vessel at C1-C2 rupture induced by the use of electrocautery was found in three patients who showed no cerebral hemodynamic deficit after hemostasis with hemostatic sponge and cotton piece.The follow-up X-ray and CT manifested osseous fusion in all the patients,with no looseness or breakage of the screws.The late follow-up showed pain associated with movement and limited range of motion in four patients(11%)and occipital neuralgia in one.Conclusions An occiput-cervicle fixation fusion or a C1-C2 fixation fusion combined with short external fixation can reestablish the upper cervical stability and prevent further injury of the spinal cord and nerve function and hence is an ideal option for C1 burst fracture with or without rupture of the transverse ligament.

Safety factors for anterior pedicle screw fixation tunnel in axis / 中华创伤杂志

Objective To investigate feasibility and safety of anterior pedicle screw fixation tunnel in the axis so as to provide theoretic evidence for further clinical application.Methods Thirty-two dry axis specimens were used for anterior pedicle screw placement,and the length of pedicle crews tunnel was measured by a digital caliper.The extraversion angle and the downslope angle were determined by CT cross-sectional scanning and reconstruction.Results All the anterior pedicle screws were positioned well,with no perforation of the pedicle.The anchoring point was at the vertex between the vertebral body and the superior articular process,with axis pedicle length of(28.4 ± 2.5)mm,the extraversion angle of (28.5 ±2.3)°and the downslope angle of(15.5 ±2.0)°.Conclusions Anterior pedicle screw fixation tunnel is feasible in the axis and can keep away from some important anatomy structures including transverse foramen,vertebral artery groove and vertebral canal to provide large safety space.

Clinical evaluation of three types of combined posterior atlantoaxial internal fixation techniques for treatment of atlantoaxial instability / 中华创伤杂志

Objective To assess clinical curative effect of three types of combined posterior atlantoaxial internal fixation techniques in treatment of atlantoaxial instability. Methods The study involved 68 patients with atlantoaxial instability treated with different fixation techniques from August 2002 to March 2008. ( 1 ) Transpedicular fixation was performed in 32 patients including 20 patients with Anderson Ⅱ odontoid fractures (seven with old odontoid fracture and 13 with fresh fractures), six with type Anderson Ⅲ fresh odontoid fractures, four with disrupt of transverse ligament of the atlas and two with congenital loose odontoid process combined with atlantoaxial instability. (2) Transpedicular internal fixation with screws of atlas incorporating C2 laminar screws was performed in 20 patients with upper cervical injury including eight with type Ⅱ odontoid process fractures combined with atlantoaxial backward dislocation,four with type Ⅱ odontoid process fractures combined with atlantoaxial forward dislocation, two with nonunion of odontoid process fractures, three with type Ⅲ odontoid process fractures combined with atlantoaxial unsteadiness and three with atlantoaxial dislocation combined with disrupt of transverse ligament of atlas. (3)A total of 16 patients with traumatic atlantoaxial instability, reducible atlantoaxial dislocation and irreducible atlantoaxial dislocation were treated with four-point internal fixation technique using autologous iliac bone grafts. Results (1) A total of 120 screws were implanted in 32 patients, with no spinal cord or vertebral artery injury after surgery. Atlas lateral mass fixation was adopted in three patients because of broken posterior arch of the atlas. Postoperative CT showed that two screws were inserted into the vertebral artery hole and that one screw was inserted medially into the spinal canal and caused medial correx rupture, but both with no clinical symptoms. All 32 patients were followed up for 6-42 months ( average 26 months), which showed solid fusion in all patients. The postoperative JOA scores ranged from 13.2 points to 16.8 points (average 14. 8 points). (2) Thirty-two screws were implanted in 20 patients,with no spinal cord or vertebral artery injury. The patients were followed up for mean six months ( range 6-14 months). Postoperative X-ray showed sound bone fusion, with no cervical instability, loosening or breakage of the screws. (3) The symptoms of all the patients were improved at different degrees, with no neurological deterioration or severe complications, such as nerve blood vessel injury. All 16 patients were followed up for 8-26 months ( average 16 months), which showed bony fusion in all patients at 3-6 months after surgery. The spinal cord function was improved markedly in five patients, good in eight, mild in two but unchanged in one. Conclusions Three types of combined posterior atlantoaxial internal fixation techniques have advantages of rigid, short-segmental and three-dimensional fixation and hence are effective methods for treatment of upper cervical injuries. The combination mode can be varied according to specific condition of the patients.

Treatment strategies for lower cervical distractive flexion injuries / 中华创伤杂志

Objective To discuss the strategies for treatment of lower cervical distractive flexion injuries. Methods Sixty-eight patients including 43 males and 25 females at age range of 18-72 years (average 43 years) suffered from lower cervical distractive flexion injuries were operated from January 2002 to June 2007. According to Allen's classification, there were 7 patients at grade Ⅰ, 19 at grade Ⅱ,29 at grade Ⅲ and 13 at grade Ⅳ. Temporary skull traction was used for each subject before surgery. Only posterior approach was performed in 26 patients who were fixated by pedicle screw system,lateral mass screw system or transarticular screw system. Combined anterior and posterior approach was applied for the other 42 patients at one stage. The curative effect was followed up for all patients after the procedures. Results All patients were followed up for 6-65 months ( average 34 months), which showed posterior incision infection in 2 patients who were cured after debridement or change dressing. Two patients with aggravated neural symptome were cured following treatment with methylprednisolone. Neural function was improved at least for one level in all patients except for 18 patients (Frankel A). Of 11 patients at grade B, there were 4 patients improved to grade C and 5 to grade D. Of 10 patients at grade C, there were 6 patients recovered to grade D and 4 to grade E. All 15 patients at grade D reached grade E. It was not found loosening, breakage or defuxion. The graft bone was fused within 3-4 months, with no any complications related to surgical fixation. Conclusions The strategies for lower cervical distractive flexion injuries should be taken according to Allen' s classification. Single posterior procedure is suitable for grade Ⅰ and Ⅱ injuries. While combined posterior and anterior procedure can be used for grade Ⅲ and Ⅳ injuries.