Surgical Correction in Patients with Lumbar Degenerative Kyphosis Who Had Low Bone Mineral Density: An Analysis of 40 Patients with a Minimum Follow-Up of Two Years

STUDY DESIGN: Retrospective study. PURPOSE: To investigate influence of bone mineral density (BMD) on the surgical correction of lumbar degenerative kyphosis (LDK). OVERVIEW OF LITERATURE: No studies so far have reported the influence of BMD on the surgical correction of LDK. METHODS: Forty LDK patients with more than 2 years follow-up were studied. Pelvic incidence (PI), pelvic tilt, sacral slope, sagittal vertical axis (SVA), lumbar lordosis (LL), and thoracic kyphosis were measured preoperatively, immediate postoperatively and at final follow-up. Adverse outcomes: proximal adjacent fractures, sagittal decompensation, pseudoarthrosis, and cage subsidence were documented. RESULTS: There were 37 females and 3 males. Average age was 65.1+/-4.5 years and mean follow-up was 34.2+/-16.7 months. 42.5% were Takemitsu type 3 curves, 27.5% type 2, 20.0% type 4 and 10.0% type 1. 37.5% had osteopenia, 40.0% osteoporosis and 22.5% had severe osteoporosis. SVA improved from 237.0+/-96.7 mm preoperatively to 45.3+/-41.8 mm postoperatively (p=0.000). LL improved from 10.5degrees+/-14.7degrees to -40.6degrees+/-10.9degrees postoperatively (p=0.000). At final follow-up SVA deteriorated to 89.8+/-72.2 mm and LL to 34.7degrees+/-15.8degrees (p=0.000). The association between late sagittal decompensation, pseudoarthrosis, or proximal adjacent fractures and osteoporosis was insignificant. The difference between immediate postoperative LL and PI (PIDiff) had a significant association with sagittal decompensation and pseudoarthrosis. CONCLUSIONS: Osteoporosis did not influence the degree of correction, late sagittal decompensation, proximal adjacent fractures, and pseudoarthrosis in LDK. PIDiff had a significant association with sagittal decompensation and pseudoarthrosis.

Restoration of Lumbar Lordosis in Flat Back Deformity: Optimal Degree of Correction

STUDY DESIGN: A retrospective comparative study. PURPOSE: To provide an ideal correction angle of lumbar lordosis (LL) in degenerative flat back deformity. OVERVIEW OF LITERATURE: The degree of correction in degenerative flat back in relation to pelvic incidence (PI) remains controversial. METHODS: Forty-nine patients with flat back deformity who underwent corrective surgery were enrolled. Posterior-anterior-posterior sequential operation was performed. Mean age and mean follow-up period was 65.6 years and 24.2 months, respectively. We divided the patients into two groups based on immediate postoperative radiographs-optimal correction (OC) group (PI-9degrees or =55degrees). Radiological and clinical results were analyzed. RESULTS: Patients in OC group had significantly less correction loss and maintained normal sagittal alignment (sagittal vertical axis<5 cm), as compared to patients in UC group (p<0.05). LL of low PI group significantly maintained within 9degrees better than high PI group (p<0.05). Oswestry disability index (ODI) significantly decreased at last follow-up, as compared to preoperative state. However, there was no significant difference in last follow-up ODI between the groups. CONCLUSIONS: In flat back deformity, correction of LL to within 9degrees of PI will result in better sagittal balance. Thus, we recommend sufficient LL to prevent correction loss, especially in patients with high PI.

The Impact of Lumbar Lordosis on the Adjacent Segment Disease after Posterior Lumbar Interbody Fusion

STUDY DESIGN: A retrospective study. OBJECTIVES: We analyzed the risk factors and relevance of lumbar lordosis on the incidence of adjacent segment disease after posterior lumbar interbody fusion. SUMMARY OF LITERATURE REVIEW: Maintaining lumbar sagittal balance is important for decreasing the incidence of adjacent segment disease after posterior lumbar interbody fusion. MATERIALS AND METHODS: Among the patients who had undergone posterior lumbar interbody fusion of 1 or 2 levels between August 2001 and October 2008, we analyzed 153 patients who were available for at least three years of follow-up; among the subjects, 115 were males and 38 were females. Mean age among the patients at the time of initial surgery was 60.3 (range, 41-82) and mean followup period was 5.6 years (range, 3-11). The causative diseases were spinal stenosis in 78 cases, degenerative spondylolisthesis in 51 cases, isthmic spondylolisthesis in 23 cases, and degenerative disc disease in 1 case. At last follow-up, there were 52 cases (33.9%) of adjacent segment disease. Among them were found 21 cases (40.4%) of disc degeneration, 17 cases (32.7%) of instability, and 14 cases (26.9%) of simultaneous disc degeneration and instability. A total of 10 patients (6.5%) underwent a revision operation, and the mean period from initial to revision operation was 5.5 years (range, 3.1-10.3). We analyzed the correlation between risk factors of adjacent segment disease and the incidence of the disease depending on the gap between lumbar lordosis and pelvic incidence, and compared the clinical results of the 2 groups using modified Whitecloud classification. RESULTS: The incidence of adjacent segment disease was not statistically significant for patient age, sex, BMD, degree of obesity, causative disease, and the level of previous surgery. However, the incidence of adjacent segment disease was statistically higher in patients who had more than 9 degrees gap between lumbar lordosis and pelvic incidence (p=0.013). In our analysis of clinical results, 63.5% of the group of patients who developed adjacent segment disease and 80.2% of the group without adjacent segment disease had good or satisfactory results (p=0.031). CONCLUSIONS: Maintaining lumbar sagittal balance is important for decreasing the incidence of adjacent segment disease after posterior lumbar interbody fusion, and close observation is needed in patients with 9 or more degrees gap between lumbar lordosis and pelvic incidence.

Computer-Assisted Total Hip Arthroplasty

Despite the overall satisfactory results of total hip arthroplasty, post-operative complications continue to occur. To minimize these problems, computer-assisted total hip arthroplasty using navigation or robot-assisted systems is being developed. A navigation system is defined as a system that locates a position in three-dimensional space and traces the target spot, and a robot-assisted system is defined as a system that performs operations automatically with mechanical robot arms based on prior preoperative planning. Computer-assisted surgeries have shown superior results to conventional methods in implant positioning, fixation, and accurate lower extremity alignment in the limited reports available. However, computer-assisted surgeries take longer compared to conventional methods. Due to the extra time needed, the risk of postoperative infection and blood loss is considered to be higher. Nevertheless, robot-assisted system is being developed for the field of hip arthroplasty, and thus its efficacy and accuracy needs to be further investigated. Since these methods have other advantages compared to conventional methods, they are the focus of much interest.

Survival improvement with combined radio-chemotherapy in the primary central nervous system lymphomas

The benefits of radio-chemotherapy in HIV-negative primary central nervous system (CNS) lymphomas were analyzed in 40 patients, who received radiotherapy to the brain or craniospinal axis with the total dose of 4460-5940 cGy to the primary tumor. Radiotherapy was followed by systemic chemotherapy, mainly with the cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) regimen, in 16 of the patients. Follow-up ranged from four to 95 months with a median of 15 months. The relapse rate was 72.5%, and 83% of the relapses occurred within the radiation field. Median survival was 19 months and the two-year survival rate was 41%. Survival was significantly influenced by treatment method and radiation dose when measured by univariate analysis; median survival and the two-year survival rate was 29 months and 63% after radio-chemotherapy, while 13.5 month and 29% after radiotherapy alone (p= 0.027), and 22 months and 49% with doses of 50 Gy or more, but 12.5 months and 13% with doses less than 50 Gy (p=0.009). However, statistical significance was lost in multivariate analysis. These results might suggest the short-term efficacy of radio-chemotherapy, however, cautious observation is needed to confirm long-term effects.