【Abstract】 Objective To discuss the main points of techniques and ranges of fusion in posterior operation ofdegenerated lumbar scol iosis compl icated spinal stenosis. Methods From February 2001 to September 2006, 23 cases with degenerated lumbar scol iosis stenosis were treated by posterior operation. There were 9 males and 14 females, with the average age of 65.3 years (ranging from 52 years to 71 years). The course of the diseases was 4 to 8 years. All patients were presented with severe low back pain. All patients were measured for Cobb angle of curves(17° to 53°), and lordosis angle of lumbar (-20° to -10° 10 cases, -40° to -20° 13 cases). Ten cases in which Cobb angle was smaller than 20° were operated by l imited segmental decompression of spinal canal, posterior intervertebral fusion and short transpedical instrument fixation. For the rest 13 cases in which Cobb angle was bigger than 20° were operated by canal decompression, longer instrument for scol iosis correction, intervertebral fusion and posterior-lateral fusion. The fixation and fusion were located at L4-S1 in 6 cases, L1-5 in 5, L2-5 in 4, L1-S1 in 5, L2-S1 in 2 and T10-S1 in 1. Results There was no patient who died from the operation. Average Cobb angle in coronal plane was 0° to 21° with the average of 15.6°. The lumbar lordosis angle was -48.0° to -18.2° with the average of -36.4°. There were 21 cases (91%) with sciatica and intermittent claudication who were clearly released. There were 20 cases (87%) whose low back pain intensely decreased. Three cases with drop-foot returned to normal activities. During the mean 15-month (6 to 54 months) follow-up for 23 cases, there was no change of corrected results and fusion rate was 100%. Conclusion For degenerated lumbar scol iosis patients, the most important purpose of the treatment is to improve cl inical symptoms through sufficient decompression of neural structures. Lumbar stabil ization reconstruction and benign spinal biomechanics l ine conduce to longterm curative effect. Overall estimate of the cl inical appearances and imageology characters is necessary when the decision, that segments are needed to be fixed and fused should be made. The strategy of the individual ized treatment may be the best choice.
Objective To evaluate the biomechanical characteristicsof titanium mesh with anterior plate fixation or ilium autograft in anterior cervical decompression.Methods Six fresh cervical spine specimens(C3-7) of young cadaver were used in the biomechanical test. After C5, C5,6 and C4-6 were given vertebrectomy,ilium autograft and titanium mesh with anterior plate fixation were performed. Their stabilities of flexion,bilateral axial rotation,the lateral bending and the extension were tested. Intact cervical spine specimens served as control group. Results Ilium autograft improved the stability of the unstable cervical vertebrae and decreased the flexion, the lateral bending or the extension, showing a significant difference when compared with control group(Plt;0.05). Whereas, axial rotational motion was decreased insignificantly(Pgt;0.05). Titanium meshwith anterior plate fixation improved the stability of the unstable spine and decreased the flexion,the bilateral axial rotation,the lateral bending or the extension, showing a significant difference when compared with control group(Plt;0.05). Conclusion The vertebrectomy and anterior cervical fusion by ilium autograft was the least stable construct of all modes tested,and the titanium mesh implantation is stabler than the intact cervical sample.
Objective To introduce operation skill of the spinal wedge osteotomy by posterior approach for correction of severe rigid scol iosis and to discuss the selection of the indications and the range of fusion and fixation. Methods Between July 1999 and January 2009, 23 patients with severe rigid scol iosis were treated with spinal wedge osteotomy by posterior approach, including 16 congenital scol iosis, 5 idiopathic scol iosis, and 2 neurofibromatosis scol iosis. There were 11 males and 12 females with a median age of 15 years (range, 8-29 years). Two patients had previous surgery history. The Cobb’s angles of scol iosis and kyphosis before operation were (85.39 ± 13.51)° and (56.78 ± 17.69)°, respectively. The mean spinal flexibil ity was 14.4% (range, 4.7%-22.5%). The trunk shift was (15.61 ± 4.89) mm. The preoperative CT or MRI showed bony septum in the canal in 2 patients. Results The mean operative time was 241 minutes and the mean blood loss was 1 452 mL. The average fused vertebrae were 10.7 segaments (range, 8-14 segaments). The follow-up ranged from 1 to 4 years with an average of 2 years and 6 months. The postoperative Cobb’s angle of scol iosis was (38.70 ± 6.51)°, the average correction rate was 54.7%. The postoperative Cobb’s angle of kyphosis was (27.78 ± 6.01)°, the average correction rate was 51.0%. The trunk shift was improved to (4.69 ± 1.87) mm, the increased height was 5.2 cm on average (range, 2.8-7.7 cm). The Cobb’s angle of scol iosis was (41.57 ± 6.80)° with an average 2.9° loss of correction at the final follow-up; the Cobb’s angle of kyphosis was (30.39 ± 5.94)° with an average 2.6° loss of correction at the final follow-up; the trunk shift was (4.78 ± 2.00) mm at the final follow-up. There were significant differences (P lt; 0.05) in the Cobb’s angles of scol iosis and kyphosis and the trunk shift between preoperation and postoperation, between preoperation and last follow-up. Four cases had pedicle fracture, 1 had L1 nerve root injury, 2 had superior mesenteric artery syndrome, 1 had exudates of incision, and 2 had temporary dysfunction of both lower extremity. Conclusion Spinal wedge osteotomy by posterior approach is a rel iable and safe surgical technique for correcting severe rigid scol iosis. With segmental pedical screw fixation, both the spinal balance and stabil ity can be restored.
Objective To discuss operative strategies of posterior deformity vertebra resection and instrumentation fixation in the treatment of congenital scol iosis or kyphoscol iosis in child and adolescent patients, and to evaluate the surgicalresults. Methods From May 2003 to December 2007, 28 patients with congenital scol iosis or kyphoscol iosis were treatedwith one stage posterior deformity vertebra resection. There were 11 males and 17 females with an average age of 9.6 years (1.5-17.0 years). The locations were thoracic vertebra in 13 cases, thoracolumbar vertebra in 10 cases, and lumbar vertebra in 5 cases. All the patients underwent one stage posterior deformity vertebra resection, fusion and correction with pedicle instrumentation. According to different types of deformities, the patients underwent three different surgeries: hemivertebra resection (13 patients), hemivertebra resection combined contralateral unsegmental resection (7 patients), and total vertebral column resection (8 patients). Based on short or long segmental pedicle instrumentation, deformities were corrected and fixed, in 7 patients with short segmental fixation (group A), in 13 patients with long segmental fixation with hemivertebra resection or combined contralateral unsegmental resection (group B), and in 8 patients with long segmental fixation with total vertebral column resection (group C). The operative duration and the volume of blood loss were recorded, and the correction rate was calculated through measurement of Cobb angles of scol iosis and kyphosis before and after operation. Results The operation time of groups A, B, and C was (98 ± 17), (234 ± 42), and (383 ± 67) minutes, respectively, and the blood loss during operation was (330 ± 66), (1 540 ± 120), and (4 760 ± 135) mL, respectively; showing significant differences among three groups (P lt; 0.05). All patients achieved one-stage heal ing of incision. No deep infection, respiratory failure or deep vein thrombosis occurred. One patient had the signs of ischemical reperfusion injury of spinal cord 6 hours after operation and recovered after 2 weeks of relative therapy in group C; no neurological compl ication occurred in other patients. The mean follow-up period was 32.8 months (24-72 months). Intervertebral rigid fusion was identified from radiological data 6 months after operation according to contiguous callus crossed intervertebral gap and maintenance of correction results. No instrumentation failure occurred. There were significant differences in the Cobb angle between before and after operations (P lt; 0.01). There were significant differences in the corrective rate of scol iosis between groups A, B and group C (P lt; 0.05). Meanwhile, there were significant differences in the corrective rate of kyphosis between groups A, C and group B (P lt; 0.05). Conclusion One-stage posterior deformity vertebra resection has a good capabil ity of correcting congenital scol iosis or kyphoscol iosis on coronal and sagittal plane rel ied on removal deformity origin. It is important to select appropriated strategies on deformity resection and segmental fixation according to different ages and deformity situations of patient.
Objective To investigate the cl inical outcomes of lumbar spondylol isthesis associated with lumbar spinal stenosis through decompressive laminectomy, spondylol ithesis reduction system (SRS) internal fixation, single posteriolateralVigor Spacer threaded fusion cages and intertransverse process arthrodesis bone grafting. Methods From June 2002 to June 2006, 58 cases of lumbar spondylol isthesis were treated with decompressive laminectomy, fixed by SRS instrumentation, posterior installed with interbody Vigor Spacer Cage and bone grafted between intertransverse process arthrodesis. There were 47 males and 11 females, aged 32-66 years old (45.8 on average). The course of disease was 3 months to 7 years, with an medium course of 25 months. Accoding to the Meyerding standard, 38 cases were classified as degree I and 20 as degree II. Spondylol isthesis between L4 and L5 covered 21 cases and between L5 and S1 covered 37 cases. There were 44 cases of lumbar spondylol isthesis and 14 of degenerative lumbar spondylol isthesis. The intervertebral height was 1.5-10.5 mm with the average of 5.1 mm. Results All patients’ incisions obtained heal ing by first intension after operation. The operation time was 50-90 minutes with an average of 65 minutes. The blood loss was 200-500 mL with an average of 250 mL. The patients were followed up for 10-38 months with an average of 23.6 months. According to the Macrab criteria, 54 cases were excellent, 3 good, 1 fair and the choiceness rate was 98.3%. According to the Meyerding classification, 38 cases of degree I and 19 out of 20 cases of degree II obtained complete reduction, and the rate of complete reduction was 98.3%. There were 57 (98.3%) cases which fused well 3-6 months after operation. The intervertebral height resumed to 9.6-12.5 mm with an average of 11.6 mm, and no intervertebral height loss was found. Conclusion The treatment of lumbar spondylol isthesis with decompressive laminectomy, SRS internal fixation, single posteriorolateral Vigor Spacer threaded fusion cage and bone grafting has excellent cl inical results and stable reduction.
Objective To compare the effectiveness of three different bone grafts [autogenous bone, allogeneic bone, and bone morphogenetic protein (BMP) composite bone] combined with screw system for spinal fusion of degenerative lumbardisease. Methods Between January 2005 and January 2010, 102 cases of degenerative lumbar disease were randomly treated with autogenous bone (group A, n=35), allogeneic bone (group B, n=33), and BMP composite bone (group C, n=34). There was no significant difference in sex, age, disease duration, affected segments, Meyerding grade, preoperative intervertebral space height, and the Japanese Orthopaedic Association (JOA) score among 3 groups (P gt; 0.05). The intervertebral space height, bone fusion rate, and JOA score were compared among 3 groups at different time points. Results All patients of 3 groups were followed up 2 to 5 years, with an average of 3.2 years. At 6 to 24 months after operation, the intervertebral space height significantly increased when compared with preoperative value in 3 groups (P lt; 0.05); the intervertebral space height of groups A and C was significantly greater than that of group B at 6, 12, 18, and 24 months after operation (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Bone graft fusion was observed at 6 months in groups A and C and at 12 months in group B; at 24 months, the rate of bone graft fusion was 100% in groups A and C, and 87.88% in group B, showing significant difference (P lt; 0.05). There was significant difference in JOA score between preoperation and postoperative 12th and 24th months (P lt; 0.05); at 12 and 24 months after operation, JOA socre and improving rate of groups A and C were significantly higher than those of group B (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Conclusion The effect of BMP composite bone is equivalent to that of autogenous bone graft in treating spinal fusion of degenerative lumbar disease, and they are better than allogeneic bone graft. BMP composite bone can obtain adequate bone grafts without invasive sampling, and has fast fusion and high successful rate.
Objective
To investigate the relationship between the volume of bone-graft and fusion efficacy in posterior lumbar interbody fusion and internal fixation of spondylolisthesis.
Methods
Between May 2004 and June 2007, 79 patients with spondylolisthesis were treated with posterior lumbar interbody fusion and internal fixation. The patients were randomly divided into 3 groups according to the volume of bone-graft for interbody fusion: group A (n=27), 5 bone granules/ cm3 on average; group B (n=26), 11 bone granules/cm3 on average; and group C (n=26), 25 bone granules/cm3 on average. There was no significant difference in gender, age, disease duration, affected segment, and the degree of vertebral slip among 3 groups (P gt; 0.05). The volume of bone-graft, the fusion rate, the loss of intervertebral height, and the incidence of internal fixation failure were compared among 3 groups.
Results
All cases were followed up 24-43 months (mean, 35 months). There were significant differences in volume of bone-graft among 3 groups (P lt; 0.05). There was no significant difference in total volume of bone-graft and Cage height among 3 groups (P gt; 0.05). The Oswestry disability index (ODI) and visual analogue scale (VAS) scores of low back pain and leg pain at last follow-up were significantly decreased when compared with preoperative scores in 3 groups (P lt; 0.05); but no significant difference was found among 3 groups (P gt; 0.05). The fusion rate was significantly higher in group B than in groups A and C, and in group A than in group C at 1 and 2 years after operation (P lt; 0.05). The change values of the intervertebral height were (2.2 ± 1.4), (0.8 ± 1.3), and (2.3 ± 1.6) mm respectively in groups A, B, and C; it was significantly lower in group B than in groups A and C (P lt; 0.05). The degree of vertebral slip at immediately after operation and last follow-up was significantly improved when compared with preoperative one in 3 groups (P lt; 0.05); the loss of vertebral slip in group B was significantly lower than that in groups A and C at last follow-up (P lt; 0.05). After operation, nail breaking occurred in 1 case (3.7%) of group C at 1 year, depinning in 1 case (3.8%) of group A at 2 years, and no nail breaking or depinning in group B. There was no significant difference in the incidence of internal fixation failure among 3 groups (χ2=3.950, P=0.604).
Conclusion
The application of bone-graft with middle volume (11 bone granules/cm3 on average) in internal fixation and posterior lumbar interbody fusion has a good imageology outcome, which can increase the fusion rate and decrease the loss of intervertebral height.
Objective
To explore the feasibility and effectiveness of spinal pedicle screw internal fixation through endoscope-assisted posterior approach for the treatment of traumatic atlantoaxial instability.
Methods
Between September 2008 and September 2010, 44 patients with traumatic atlantoaxial instability received spinal pedicle screw internal fixation through endoscope-assisted posterior operation (micro-invasive surgical therapy group, n=22) or traditional surgical therapy (control group, n=22). There was no significant difference in gender, age, type of injury, disease duration, and preoperative Japanese Orthopedic Association (JOA) score between 2 groups (P gt; 0.05). The blood loss, operation time, length of the incision, improvement rate of JOA, and graft fusion rates were compared between 2 groups to assess the clinical outcomes.
Results
The blood loss, operation time, and length of the incision in the micro-invasive surgical therapy group were better than those in control group (P lt; 0.05). All incisions were primary healing. Of 88 pedicle screws, 7 pedicle screws penetrated into the interior walls of cervical transverse foramen in the micro-invasive surgical therapy group and 8 in the control group, but there was no syndrome of vertebral artery injury. All patients of the 2 groups were followed up 12 to 37 months (mean, 26 months). Bony fusion was achieved in all cases within 3 to 12 months (mean, 5.3 months). No loosening or breakage of screw occurred. At 6 months to 1 year after operation, the internal fixator was removed in 6 cases and the function of head and neck rotary movement were almost renewed. The JOA score was significantly improved at last follow-up when compared with preoperative score (P lt; 0.05), and no significant difference in JOA score and improvement rate between the 2 groups at last follow-up (P gt; 0.05).
Conclusion
The micro-invasive surgical therapy can acquire the same effectiveness to the traditional surgical therapy in immediate recovery of stability, high graft fusion rate, and less complication. Moreover, it can significantly reduce the operation time, blood loss, and soft tissue injury, so this approach may be an ideal way of internal fixation to treat traumatic atlantoaxial instability.
Objective To investigate the stability and the stress distributions of L3-5 fused with three different approaches (interbody, posterolateral and circumferential fusions) and to investigate degeneration of thesegment adjacent to the fused functional spinal unit. Methods A detailed L3-5 three-dimensional nonlinear finite element model of a normal man aged 32 was established and validated. Based on the model, the destabilized model, the interbody, posterolateral and circumferential fusions models of L4-5 were established. After the loadings were placed on all the models, we recorded the angular motions of the fused segment and the Von Mises stress of the adjacent intervertebral disc. Results The circumferential fusion was most stable than the others, and the interbody fusion was more stable than the posterolateral fusion. The maximal Von Mises stress of the adjacent L3,4 intervertebral disc in all the models was ranked descendingly as flexion,lateral bending,torsion and extension. For the three kinds of fusions, the stress increment of the L3,4 intervertebral disc was ranked ascendingly as interbody fusion,posterolateral fusion and circumferential fusion. Conclusion After destabilization of the L4,5 segment, the stability of the circumferential fusionis better than that of the others, particularly under the flexional or extensional loading. The stability of the interbody fusion is better than that of the posterolateral fusion, except for under the flexional loading. The feasibility of adjacent segment degeneration can be ranked descendingly as: circumferential fusion,posterolateral fusion and interbody fusion.
Objective To analyze the cl inical features of scol iosis associated with Chiari I malformation in adolescent patients, and to explore the val idity and safety of one-stage posterior approach and vertebral column resection for the correction of severe scol iosis. Methods Between October 2004 and August 2008, 17 adolescent patients with scol iosis associated with Chiari I malformation were treated with surgical correction through posterior approach and pedicle instrumentation. There were 9 males and 8 females with an average age of 15.1 years (range, 12-19 years). The MRI scanning showed that 16 of 17 patients had syringomyel ia in cervical or thoracic spinal cord. Apex vertebra of scol iosis were located atT7-12. One-stage posterior vertebral column resection and instrumental correction were performed on 9 patients whose Cobb angle of scol iosis or kyphosis was more than 90°, or who was associated with apparent neurological deficits (total spondylectomy group). Other 8 patients underwent posterior instrumental correction alone (simple correction group). All patients’ fixation and fusion segment ranged from upper thoracic spine to lumbar spine. Results The operative time and the blood loss were (384 ± 65) minutes and (4 160 ± 336) mL in total spondylectomy group, and were (246 ± 47) minutes and (1 450 ± 213) mL in simple correction group; showing significant differences (P lt; 0.05). In total spondylectomy group, coagulation disorder occurred in 1 case, pleural perforation in 4 cases, and lung infection in 1 case. In simple correcction group, pleural perforation occurred in 1 case. These patients were improved after symptomatic treatment. All patients were followed up 24-36 months (32.5 months on average). Bony heal ing was achieved at 6-12 months in total spondylectomy group. No breakage or pull ingout of internal fixator occurred. The angles of kyphosis and scol iosis were significantly improved at 1 week after operation (P lt; 0.01) when compared with those before operation. The correction rates of scol iosis and kyphosis (63.4% ± 4.6% and 72.1% ± 5.8%) in total spondylectomy group were better than those (69.4% ± 17.6% and 48.8% ± 19.3%) in simple correction group. Conclusion Suboccipital decompression before spine deformity correction may not always be necessary in adolescent scol iosis patients associated with Chiari I malformation. In patients with severe and rigid curve or apparente neurological deficits, posterior vertebral column resection would provide the opportunity of satisfied deformity correction and decrease the risk of neurological injury connected with surgical correction.
