Risk factor analysis of disc and facet joint degeneration after intersegmental pedicle screw fixation for lumbar spondylolysis.

BACKGROUND: Patients who do not respond to conservative treatment of the isthmus are often treated with surgery. We used direct repair plus intersegment pedicle screw fixation for the treatment of lumbar spondylolysis. The aim of this observational study was to assess the effects of this technique and evaluate various risk factors potentially predicting the probability of disc and facet joint degeneration after instrumentation. METHODS: The study included 54 male L5 spondylolysis patients who underwent pars repair and intersegment fixation using pedicle screws. Bony union was evaluated using reconstruction images of computed tomography. Radiographic changes, including disc height, vertebral slip, facet joint and disc degeneration in the grade of adjacent and fixed segments, were determined from before to final follow-up. Logistic regression analysis was performed to identify factors associated with the incidence of disc and facet joint degeneration. RESULTS: Bony union was achieved in all cases. Logistic regression analysis revealed that instrumentation durations of greater than 15.5 months and 21.0 months were significant risk factors for the incidence of L4/5 and L5S1 facet degeneration, respectively. CONCLUSIONS: Intersegmental pedicle screw fixation provides good surgical outcomes and good isthmic bony union rates in patients with lumbar spondylolysis. The duration of fixation was confirmed as a risk factor for facet joint degeneration. Once bony union is achieved, instrument removal should be recommended.

Repair of symptomatic bilateral L5 spondylolysis with autogenous iliac crest graft and temporary intersegmental pedicle screw fixation in youth.

BACKGROUND: When symptomatic spondylolysis fail to respond to nonoperative treatment, surgical management may be required. A number of techniques have been described for repair by intrasegmental fixation with good results; however, there are still some problems. We reported a repair technique with temporary intersegmental pedicle screw fixation and autogenous iliac crest graft. The aim of present study is to assess the clinical outcomes of L5 symptomatic spondylolysis with this technique. METHODS: A retrospective analysis of 128 patients with L5 spondylolysis treated with this method was performed. According to CT scan, the spondylolysis were classified into 3 categories: line, intermediate, and sclerosis type. The diagnostic block test of L5 bilateral pars defect was done in all patients preoperatively. The sagittal and axial CT images were used to determine the bone union. The healing time, complications, number of spina bifida occulta, Japanese Orthopedic Association (JOA) score, and VAS for back pain were recorded. After fixation removal, the rate of ROM preservation at L5S1 was calculated. RESULTS: There were 97 patients (194 pars) followed with mean follow-up of 23 months (range, 12-36 months). The union rate of pars was 82.0% at 12 months and 94.3% at 24 months postoperatively. Low back pain VAS significantly (P < 0.05) improved from preoperative mean value of 7.2 to 1.3 at the final follow-up postoperatively (P < 0.05). JOA score increased significantly postoperatively (P < 0.05) with average improvement rate of 79.3%. The rates of L5S1 ROM preservation were 79.8% and 64.0% after fixation removal at 1 and 2 years postoperatively. There were 3 patients of delayed incision healing without other complications. CONCLUSIONS: Although sacrificing L5S1 segment motion temporarily, more stability was obtained with intersegmental fixation. This technique is reliable for spondylolysis repair which has satisfactory symptom relief, high healing rate, low incidence of complications, and preserve a large part of ROM for fixed segment.

Long-Term Outcome of Dynesys Dynamic Stabilization for Lumbar Spinal Stenosis.

BACKGROUND: Many clinical studies over the past decade have indicated positive outcomes for patients treated with Dynesys dynamic stabilization for lumbar degenerative disease. However, long-term outcomes of Dynesys for lumbar spinal stenosis are rarely reported. The aim of this study was to analyze the long-term clinical and radiologic outcomes for patients with lumbar spinal stenosis treated with Dynesys stabilization. METHODS: Thirty-eight patients with lumbar spinal stenosis were treated with Dynesys stabilization from July 2008 to March 2010. The minimal duration of follow-up was 72 months. The patients were divided into stenosis and spondylolisthesis groups according to degenerative spondylolisthesis. Clinical outcomes were evaluated using the Oswestry Disability Index (ODI) and visual analog scale (VAS). Radiographic evaluations included range of motion (ROM) and the disc heights of stabilized segments and the upper adjacent segments. We also evaluated the occurrence of radiographic and symptomatic adjacent segment degeneration (ASD). RESULTS: There were 23 patients in stenosis group and 15 patients in spondylolisthesis group. The ODI scores were significantly improved at the final follow-up evaluation, as compared to the baseline values (16.1 ± 5.7 vs. 57. 2 ± 14.2, t = 61.41, P < 0.01). The VAS scores for back and leg pain were significantly improved from 4.82 ± 0.89 and 4.04 ± 0.82 preoperatively to 0.93 ± 0.61 and 0.54 ± 0.51 postoperatively (t = 6.59, P < 0.01, and t = 5.91, P < 0.01, respectively). There were no differences between the two groups with respect to VAS and ODI scores. The ROM of stabilized segments decreased significantly from 7.8° ± 2.4° to 4.5° ± 1.5° (t = 7.18, P < 0.05), while the upper adjacent segments increased significantly from 8.3° ± 2.4° to 10.4° ± 2.4° (t = 2.87, P = 0.01). The change in disc height of stabilized segments was not significant (11.9 ± 2.1 preoperatively vs. 12.5 ± 1.5 postoperatively, t = 1.43, P = 0.15), whereas the decrease in disc height of the upper adjacent segments was significant (12.5 ± 2.0 preoperatively vs. 11.0 ± 1.7 postoperatively, t = 2.94, P = 0.01). The occurrence of radiographic and symptomatic ASD was 16% (6/38) and 3% (1/38), respectively. CONCLUSIONS: Decompression and Dynesys stabilization for lumbar stenosis with or without spondylolisthesis showed good long-term clinical and radiographic results. Lumbar stenosis with or without Grade I spondylolisthesis, particularly in patients <60 years of age with mild-to-moderate lumbar disc degeneration, would be one of the main indications for the Dynesys system.

Comparison of Functional and Radiological Outcomes Between Two Posterior Approaches in the Treatment of Multilevel Cervical Spondylotic Myelopathy.

BACKGROUND: Posterior cervical decompression is an accepted treatment for multilevel cervical spondylotic myelopathy (CSM). Each posterior technique has its own advantages and disadvantages. In the present study, we compared the functional and radiological outcomes of expansive hemilaminectomy and laminoplasty with mini titanium plate in the treatment of multilevel CSM. METHODS: Forty-four patients with multilevel CSM treated with posterior cervical surgery in Department of Orthopedic Surgery, Beijing Army General Hospital from March 2011 to June 2012 were enrolled in this retrospective study. Patients were divided into two groups by surgical procedure: Laminoplasty (Group L) and hemilaminectomy (Group H). Perioperative parameters including age, sex, duration of symptoms, operative duration, and intraoperative blood loss were recorded and compared. Spinal canal area, calculated using AutoCAD ® software(Autodesk Inc., San Rafael, CA, USA), and neurological improvement, evaluated with Japanese Orthopedic Association score, were also compared. RESULTS: Neurological improvement did not differ significantly between groups. Group H had a significantly shorter operative duration and significantly less blood loss. Mean expansion ratio was significantly greater in Group L (77.83 ± 6.41%) than in Group H (62.72 ± 3.86%) (P < 0.01). CONCLUSIONS: Both surgical approaches are safe and effective in treating multilevel CSM. Laminoplasty provides a greater degree of enlargement of the spinal canal, whereas expansive hemilaminectomy has the advantages of shorter operative duration and less intraoperative blood loss.

[Effects of vertebral height restoration of vertebroplasty for osteoporotic vertebra compression fractures].

OBJECTIVE: To evaluate the effect of vertebral height restoration of vertebroplasty for osteoporotic vertebra compression fractures (VCFs). METHODS: From October 2004 to June 2007, a total of 37 patients with 40 VCFs were treated by vertebroplasty. There were 12 males and 25 females with a mean age of (72.4 +/- 12.7) years (ranged, 48 to 87). Pain easement state was evaluated by visual analog scale (VAS) before and after operation, as well as in followed-up. Preoperative and postoperative vertebral height, kyphosis angle at fractured levels were measured on X-rays. RESULTS: All of patients were followed-up for 12 to 47 months (averaged, 35.8 +/- 9.6). The VAS score was 8.4 +/- 1.6 before operative, 2.1 +/- 1.2 at the 2nd day after operative, there were significant difference between pre-and postoperative (P < 0.05); the average follow-up VAS was 1.6 +/- 0.9, there were significant difference as compared with the preoperative (P < 0.05). Lateral X-ray showed that the preoperative degree of vertebral height in the of anterior and middle vertebral were (72.0 +/- 10.6)% and (68.0 +/- 15.6)%, and postoperative were (76.0 +/- 8.6)% and (73.0 +/-6.1)%, respectively. There were no significant difference in vertebral height between preoperative and postoperative. The vertebral kyphosis angle was corrected from preoperative (7.8 +/- 2.7) degree to postoperative (8.1 +/- 2.3) degree. CONCLUSION: Vertebroplasty is a safe and effective method for treatment of osteoporotic VCFs, it can relieve the pain effectively. Failure to restore vertebaral height does not seem to interfere with the excellent pain management.

[Clinical classification and surgical options of the far-lateral lumbar disc herniation].

OBJECTIVES: To suggest the clinical classification of the far-lateral lumbar disc herniation and offer the considerations for clinical choice of different surgical procedures. METHODS: According to the locations of the herniated disc and relevant clinical symptoms, the far-lateral lumbar disc herniation was divided into three types: Type I: posterolateral and foraminal herniation(double herniations); Type II: foraminal disc herniation and Type III: extraforaminal herniation. From January 2002 to January 2007, 38 patients with far lateral lumbar disc herniation underwent surgery in the institute. The surgical options were decided by means of the classification. The surgical procedures included (1) discectomy by inter-TP (transverse process) approach, (2) discectomy with partial facetectomy and (3) discectomy with facetectomy and PLIF (posterior lumbar interbody fusion). Among the 38 patients, there were 25 males and 13 females. The mean age was 58.4 years old. The herniated discs located at L(3-4) in 17, L(4-5) in 13, and 8 cases at L(5)S(1). Twenty-three patients were simple disc herniation, 15 cases with concomitant lumbar spinal stenosis. The symptoms and signs of exiting root compression at herniated disc level were presented in all patients and passing root compression presented in 7 Type I cases as well; while intermittent claudication being presented in 15 and low back pain in 21 patients. The VAS (visual analog pain scale) of radicular leg pain was taken before and after the operation. The postoperative outcomes were evaluated through the MacNab's method in all the patients. RESULTS: By using the new classification system, the 38 patient were divided into Type I 10 cases, Type II 19 cases and Type III 9 cases. The adopted surgeries included discectomy by intertransverse approach in 5, discectomy with partial facetectomy in 7, and discectomy with facetectomy and PLIF in the rest 26 cases. The mean follow-up period was ranging from 6 months to 4 years and 10 months, average 2 years and 11 months. The mean VAS scores of radicular pain was 7.4 preoperatively, 2.7 at 2 weeks after the operation and 3.1 at final follow-up. The final clinical outcomes by MacNab's method were as follow: excellent results in 20 cases, good in 12, fair in 5 and poor in 1 case. The overall improvement ratio was 84.2%. The postoperative complications included superficial wound infection in 1 case, insufficient decompression in 1 case and leakage of cerebrospinal fluid in 1 case respectively. No breakage and loosening of internal fixation were detected. CONCLUSIONS: A new clinical classification of far lateral lumbar disc herniation was suggested, which is significant to understanding the relevant pathology and choosing the surgical procedures.