Lumbar Degenerative Kyphosis Patients Research Articles

Strategies for prevention of rod fracture in adult spinal deformity: cobalt chrome rod, accessory rod technique, and lateral lumbar interbody fusion.

Restoring the proper sagittal alignment in adult spinal deformity (ASD) can improve radiological and clinical outcomes, but pseudarthrosis including rod fracture (RF) is a common problematic complication. The purpose of this study was to analyze the methods for reducing the incidence of RF in deformity correction of ASD. The authors retrospectively selected 178 consecutive patients (mean age 70.8 years) with lumbar degenerative kyphosis (LDK) who underwent deformity correction with a minimum 2-year follow-up. Patients were classified into the non-RF group (n = 131) and the RF group (n = 47). For predicting the crucial factors of RF, patient factors, radiographic parameters, and surgical factors were analyzed. The overall incidence of RF was 26% (47/178 cases), occurring in 42% (42/100 cases) of pedicle subtraction osteotomy (PSO), 7% (5/67 cases) of lateral lumbar interbody fusion (LLIF) with posterior column osteotomy, 18% (23/129 cases) of cobalt chrome rods, 49% (24/49 cases) of titanium alloy rods, 6% (2/36 cases) placed with the accessory rod technique, and 32% (45/142 cases) placed with the 2-rod technique. There were no significant differences in the incidence of RF regarding patient factors between two groups. While both groups showed severe sagittal imbalance before operation, lumbar lordosis (LL) was more kyphotic and pelvic incidence (PI) minus LL (PI-LL) mismatch was greater in the RF group (p < 0.05). Postoperatively, while LL and PI-LL did not show significant differences between the two groups, LL and sagittal vertical axis correction were greater in the RF group (p < 0.05). Nonetheless, at the last follow-up, the two groups did not show significant differences in radiographic parameters except thoracolumbar junctional angles. As for surgical factors, use of the cobalt chrome rod and the accessory rod technique was significantly greater in the non-RF group (p < 0.05). As for the correction method, PSO was associated with more RFs than the other correction methods, including LLIF (p < 0.05). By logistic regression analysis, PSO, preoperative PI-LL mismatch, and the accessory rod technique were crucial factors for RF. Greater preoperative sagittal spinopelvic malalignment including preoperative PI-LL mismatch was the crucial risk factor for RF in LDK patients 65 years or older. For restoring and maintaining sagittal alignment, use of the cobalt chrome rod, accessory rod technique, or LLIF was shown to be effective for reducing RF in ASD surgery.

232. Optimal lumbar lordosis correction for adult spinal deformity with severe sagittal imbalance in patients over age 65: role of pelvic tilt and pelvic tilt ratio

BACKGROUND CONTEXT The prevalence of adult spinal deformity (ASD) is increasing as the average age of the population increases. Optimal surgical correction for patients with ASD is necessary. The Scoliosis Research Society-Schwab classification is used for optimal surgical correction in many spinal reconstruction surgeries, and the targets to obtain satisfactory alignment and favorable outcomes are ≤10° for pelvic incidence (PI) minus lumbar lordosis (LL), 20°, while pathologic based on Schwab criteria, may be a natural phenomenon in patients with a large PI. Therefore, the concept of global tilt has been introduced recently, and to overcome the limitations of PT in our study, a PT ratio value (PTr) of PT/PI x 100% was calculated along with measurement of PT. PURPOSE The purpose of this study was to evaluate optimal and ideal target values including PTr of the spine balance correction in elderly patients with ASD who were over the age of 65 years. STUDY DESIGN/SETTING Retrospective, consecutive case review. PATIENT SAMPLE A total of 121 patients (average age 70.5 years and a minimum 2-year follow up) with lumbar degenerative kyphosis (LDK) who underwent long-segment fusion from T10 to sacrum. OUTCOME MEASURES Description and analysis of x-ray changes. METHODS Based on the correction angle of their LL and incorporating PI, the patients were divided into 5 groups using the Schwab classification. Clinical and radiologic parameters were analyzed: Group 1 was 10 RESULTS The groups that showed 80% or more optimal sagittal alignment at their postoperative (Post) and the last follow-up (Last), were group 3, 4, and 5. Post and Last thoracic kyphosis (TK) were increased naturally. Post PT was decreased, but group 1 and 2 did not meet Schwab's target value, and the Post and Last PTr showed a tendency to decrease from group 1 to group 5 as LL increased. Based on correlation test with Post SVA, TK correction and SVA correction, Post lumbosacral angle, Post LL, PI–LL, Post PTr and Post PT were associated. Logistic regression analysis with these correlation factors led to risk factors of Post sagittal imbalance, and after confirming the significance of each path, it was confirmed that the effects of PI–LL and Post PTr were valid (p CONCLUSIONS Our study showed that undercorrection showed unfavorable results for the correction of LDK patients over age 65. Therefore, the restoration of global sagittal balance is more important, and through our study, the risk factors of Post sagittal imbalance were the value of PI–LL and that of PTr, and target value of PI-LL was FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Transcutaneous neuromuscular electrical stimulation applied to optimal points on the lower abdomen and lumbar paraspinal region changes gait parameters in patients with lumbar degenerative kyphosis.

Lumbar degenerative kyphosis (LDK) is characterized by sagittal imbalance resulting from degenerative loss of lumbar lordosis. The ability of transcutaneous neuromuscular electrical stimulation (NMES) to activate deep lumbar stabilizing muscles has been demonstrated. The aim of this study was to evaluate the effects of transcutaneous NMES applied to optimal points on the lower abdomen and lumbar paraspinal region on gait problems in patients with lumbar degenerative kyphosis (LDK). Twenty-one patients with lumbar degenerative kyphosis underwent three walking sessions in the following order; walking for 5 minutes without NMES, walking with NMES on the lumbar multifidus (LM) only, and walking with NMES on both LM and transverse abdominis (TrA)/obliquus internus (OI). Differences in gait parameters at the commencement and completion of each of the three sessions were evaluated by gait analysis. During the 5-minute walk with NMES applied to the LM or to the LM and TrA/OI, participants showed lesser increases in spine forward tilt, pelvic anterior tilt, and external foot progression angle, and a lesser decrease in hip internal rotation than when walking without NMES (P< 0.05). In addition, with NMES, patients showed less decrement in gait velocity and stride length at walk completion than patients walking without NMES (P< 0.05). However, in the comparison between walks with NMES applied to the LM and walks with NMES applied to the LM and TrA/OI, we could not find any significant difference in changes of gait parameters (p> 0.05). Transcutaneous NMES applied at optimal points on the lower abdomen and back could provide a means of treating gait problems caused by a stooped trunk in LDK patients.

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 DesignRetrospective study.PurposeTo investigate influence of bone mineral density (BMD) on the surgical correction of lumbar degenerative kyphosis (LDK).Overview of LiteratureNo studies so far have reported the influence of BMD on the surgical correction of LDK.MethodsForty 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.ResultsThere 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 10.5°±14.7° to -40.6°±10.9° postoperatively (p=0.000). At final follow-up SVA deteriorated to 89.8±72.2 mm and LL to 34.7°±15.8° (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.ConclusionsOsteoporosis 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.

Analysis of the incidence and risk factors for the progression of proximal junctional kyphosis following surgical treatment for lumbar degenerative kyphosis: minimum 2-year follow-up

Background context. Proximal junctional kyphosis (PJK) following surgical treatment of lumbar degenerative kyphosis (LDK) is one of the critical complications leading to the failure of instrumentation and additional extensive surgery. However, most previous studies have focused on idiopathic scoliosis resulting from variable surgical techniques. LDK usually differ from other scoliotic deformities in terms of patient characteristics and disease mechanisms. Purpose. Identification of the prevalence of PJK after the surgical treatment of LDK and searching for the predictable value for the progression of PJK. Study design. Retrospective comparative study. Patient sample (must be included in clinical studies). Forty-seven consecutive patients who underwent surgical correction of a sagittal imbalance due to LDK, from January 2005 to December 2008 in a single spine clinic, were evaluated with a minimum 2 years follow-up (mean 3.8 years). Methods. Patients were divided into 2 groups: with or without the occurrence of PJK, and three categorized factors according to patient characteristics, surgical variables, and the radiographic spinopelvic parameters were evaluated. Results. PJK had occurred in 29 of 47 patients (61.7%). Among variable factors, old age, upper-instrumented vertebra below L2, lumbar lordosis to PI ratio, and the sum of lumbar lordosis, and the sacral slope related to PI were found to be statistically significant. Conclusions. The overall incidence of PJK following surgical treatment of LDK patients was higher than expected. Spinal biomechanics may be changed after long instrumented fusion surgery. Thorough consideration of these factors is needed in the treatment strategy of LDK patients. A long-term follow-up study should be conducted.

Radiological analysis of lumbar degenerative kyphosis in relation to pelvic incidence

Lumbar degenerative kyphosis (LDK) is characterized by sagittal imbalance resulting from a loss of lumbar lordosis (LL). The pelvic incidence (PI) regulates the sagittal alignment of the spine and pelvis. The purpose of this study is to evaluate the spinopelvic parameters in patients with LDK and to compare them with those of a normal population. A cross-sectional study. The selected patients showed characteristic clinical features of LDK. As control group, asymptomatic volunteers without spinal pathology were recruited. Full-length radiographs of the spine in the anteroposterior and lateral planes were taken, extending from the base of the skull to the proximal femur. Pelvic incidence, sacral slope (SS), pelvic tilt (PT), main thoracic kyphosis (TK), thoracolumbar junction (TLJ), LL, and sagittal vertical axis (SVA) were evaluated. In terms of PI, the patient and control groups were divided into three groups: low (PI≤45°), middle (45°<PI≤60°), and high PI groups (PI>60°). All the spinopelvic parameters were compared between each group and between the patient and control groups in each group. The correlations between each of the parameters were analyzed. We evaluated 172 patients with symptomatic LDK and 39 healthy volunteers. The number of LDK patients with low, middle, and high PI groups were 44 (25.6%), 72 (44.8%), and 51 (29.6%), respectively. In the control group, the number of low, average, and high PI patients were 18 (46.2%), 15 (38.5%), and 6 (15.4%), respectively. In the control group, PI determined all spinopelvic parameters except SVA. In the LDK group, PI also determined spinopelvic parameters except for TK and SVA. Lumbar degenerative kyphosis with low PI was associated with pronounced kyphosis in LL and TLJ; LDK with a high PI was associated with relatively preserved lordosis in LL with a flat or lordotic TLJ. In terms of pelvic parameters, low PI showed flattened SS and low PT, whereas high PI showed steep SS and high PT. The results of this study suggest the importance of the key anatomical parameter, PI, in the determination of sagittal contour in symptomatic LDK patients and normal population. Spinopelvic parameters and pelvic compensatory mechanisms in LDK patients differ according to PI. Identifying the spinopelvic parameters is useful when correcting deformities.

Sagittal Decompensation After Corrective Osteotomy for Lumbar Degenerative Kyphosis

A retrospective study To classify the types and identify related factors on sagittal decompensation after corrective osteotomy for lumbar degenerative kyphosis (LDK). There has been a skeptical view of surgical treatment of LDK owing to loss of sagittal balance even after correction of kyphosis. However, there had been no report on the classification and risk factors of sagittal decompensation. A total of 23 LDK patients who had undergone corrective osteotomy were enrolled. The mean follow-up period was 45.7 months. Radiographic parameters including sagittal balance, the cross-sectional area of paravertebral muscles, were analyzed. We classified the type of sagittal decompensation into thoracic (Group T) and lumbar decompensation (Group L) with a reference line from the posterosuperior corner of the sacrum to the center of the T12-L1 disc. The type of sagittal decompensation was defined with the location of T1 and the reference line at the last follow-up radiographs. The mean number of fusion segments was 7.7. Sagittal balance improved from 26.4 cm to 4 cm immediately after operation but deteriorated to 11.2 cm at the last follow-up. The decompensation was greater in Group T (11 cases) than in Group L (12 cases) (9.1 cm vs. 5.2 cm, P = 0.03). The comparative analysis showed significant differences between groups T and L in thoracic kyphosis at the last follow-up (Group T:L = 40.5°:27.5°, P = 0.04), preoperative thoracic kyphotic angle (Group T:L = 19.6°:-1°, P = 0.01), mean ratio of cross-sectional area of paravertebral muscles to intervertebral disc in T12-L1, and incidence of the preoperative compensatory thoracic lordosis (Group T:L = 27.3%:100%, P = 0). The mean sagittal decompensation after corrective osteotomy for LDK was 38.3%. The etiology was loss of lumbosacral lordosis in Group L and progression of kyphosis at the proximal unfused segments in addition to lumbosacral loss in Group T. The decompensation was greater in the thoracic type than in the lumbar type and was considered relevant to a large preoperative thoracic kyphotic angle, absence of compensatory thoracic lordosis, and atrophy of paravertebral muscles.

Influence of Lumbar Lordosis Restoration on Thoracic Curve and Sagittal Position in Lumbar Degenerative Kyphosis Patients

A retrospective study. To determine postsurgical correlations between thoracic and lumbar sagittal curves in lumbar degenerative kyphosis (LDK) and to determine predictability of spontaneous correction of thoracic curve and sacral angle after surgical restoration of lumbar lordosis and fusion. To our knowledge, there are only a limited number of articles about the relationship between thoracic and lumbar curve in sagittal thoracic compensated LDK. Retrospective review of 53 consecutive patients treated with combined anterior and posterior spinal arthrodesis. We included patients with sagittal thoracic compensated LDK caused by sagittal imbalance in this study. Total lumbar lordosis, thoracic kyphosis, sacral slope, and C7 plumb line were measured on the pre- and postoperative whole spine lateral views. Postoperative changes in thoracic kyphosis, sacral slope, and C7 plumb line according to the surgical lumbar lordosis restoration were measured and evaluated. The mean preoperative sagittal imbalance by plumb line was 78.3 mm (+/-76.5); this improved to 13.6 mm (+/-25) after surgery (P < 0.0001). Mean lumbar lordosis was 9.4 degrees (+/-19.2) before surgery and increased to 38.4 degrees (+/-13.1) at follow-up (P < 0.0001). Mean thoracic kyphosis was 1.1 degrees (+/-12.7) before surgery and increased to 17.6 degrees (+/-12.2) at follow-up (P < 0.0001). Significant preoperative correlations existed between kyphosis and lordosis (r = 0.772, P < 0.0001) and between lordosis and sacral slope (r = 0.785, P < 0.0001). Postoperative lumbar lordosis is correlated to thoracic kyphosis increase (r = 0.620, P < 0.0001). Postoperative lumbar lordosis is correlated to sacral slope increase (r = 0.722, P < 0.0001). Reciprocal relationship exists between lumbar lordosis and thoracic kyphosis in sagittal thoracic compensated LDK. Surgical restoration of lumbar lordosis for LDK brings about high level of statistical correlation to thoracic kyphosis improvement. At the same time, the reciprocal relationship is maintained.

CAN PATIENTS WITH SAGITTALLY WELL-COMPENSATED LUMBAR DEGENERATIVE KYPHOSIS BENEFIT FROM SURGICAL TREATMENT FOR INTRACTABLE BACK PAIN?

To analyze pre- and postoperative x-rays of sagittal spines and to review the surgical results of 21 patients with lumbar degenerative kyphosis whose spines were sagittally well compensated by compensatory mechanisms but who continued to suffer from intractable back pain We performed a retrospective review of 21 patients treated with combined anterior and posterior spinal arthrodesis. Inclusion criteria were: lumbar degenerative kyphosis patients with intractable back pain and whose spines were sagittally well compensated by a compensatory mechanism, defined as a C7 plumb line to the posterior aspect of the L5-S1 disc of less than 5 cm. Outcome variables included: radiographic measures of preoperative, postoperative, and follow-up films; clinical assessment using the mean Numeric Rating Scale, Oswestry Disability Index, and Patient Satisfaction Index; and a review of postoperative complications. All patients were female (mean age, 64.5 years; age range, 50-74 years). The mean preoperative sagittal imbalance was 19.5 (+/- 17.6) mm, which improved to -15.8 (+/- 22.2) mm after surgery. Mean lumbar lordosis was 13.2 degrees (+/- 15.3) before surgery and increased to 38.1 degrees (+/- 14.4) at follow-up (P < 0.0001). Mean thoracic kyphosis was 5.5 degrees (+/- 10.2) before surgery and increased to 18.9 degrees (+/- 12.4) at follow-up (P < 0.0001). Mean sacral slopes were 12.9 degrees (+/- 11.1) before surgery and increased to 26.3 degrees (+/- 9.6) at follow-up (P < 0.0001). The mean Numeric Rating Scale score improved from 7.8 (back pain) and 8.1 (leg pain) before surgery to 3.0 (back pain) and 2.6 (leg pain) after surgery (P < 0.0001). The mean Oswestry Disability Index scores improved from 56.2% before surgery to 36.7% after surgery (P < 0.0001). In 18 (85.5%) of 21 patients, satisfactory outcomes were demonstrated by the time of the last follow-up assessment. This study shows that even lumbar degenerative kyphosis patients with spines that are sagittally well compensated by compensatory mechanisms may suffer from intractable back pain and that these patients can be treated effectively by the restoration of lumbar lordosis.

Change of Pelvic Tilt before and after Gait in Patients with Lumbar Degenerative Kyphosis

- Abstract - Study Design: This is a retrospective study. Objectives: We wanted to verify the value of radiography and gait analysis to analyze the changes of the pelvic tilt before and after gait in the patients with LDK. Summary of Literature Review: Patients with lumbar degenerative kyphosis show dynamic changes that are closely associated with the motion of pelvis. Materials and Methods: We analyzed 18 lumbar degenerative kyphosis patients who didn't have multiple vertebral compressio fractures, a past history of spinal surgery or surgery for degenerative arthritis of the knee or hip, and obesity which causes marker errors on the gait analysis. Pelvic tilt was statistically evaluated by utilizing radiographs and dynamically utilizing the gait analysis. The linear parameters of the gait cycle and the kinematic data were obtained from the gait analysis. Results: The LDK patients' mean walking velocity was 80.7 cm/s, and it was largely decreased to 65% of the normal value. The cause of the decreased walking velocity was a decrease of stride length, and not a decrease of cadence. The mean static pelvic tilt in the gait analysis was -1.3±8.0。 , and there were 8 cases of anterior tilt and 10 cases of posterior tilt. The mean pelvic tilt during gait was 12.5±8.2。 , and there were 17 cases of anterior tilt and 1 case of posterior tilt. It was statistically significant dif- ference (p<0.05) between the mean static pelvic tilt in gait analysis and the mean pelvic tilt during gait and the Pearson's corre- lation coefficient was -0.88. Conclusions: Though there was no statistical significance, we observed anterior pelvic rotation after gait on the radiographs. As fatigue of the pelvic extensor muscles increases during gait, anterior pelvis tilt increases with statistical significance on the gait analysis. Therefore, we feel gait analysis is useful for evaluating the dynamic change of the pelvic tilt in patients with LDK.

Radiologic Analysis of Postoperative Sagittal Plane Correction in Lumbar Degenerative Kyphosis (LDK)

� - Abstract - Study D Design: This is a retrospective study Objectives: We radiologically analyzed the correction of the sagittal imbalance and the proximal fusion level to prevent correc- tion loss and the usefulness of iliac screws in LDK. Summary o of tthe L Literature R Review: Complications can be encountered during fixation and fusion as most of the LDK patients are aged, and the osteoporosis that causes fixation loss is known to affect the loss of correction. Materials aand M Methods: We analyzed the cause of correction loss among 35 patients who underwent surgery and who were followed up for at least 1 year. All the patients had performed gait analysis before operation. The operative techniques were pedicle subtraction osteotomy and fixation to S1. For analyzing causes of correction loss, we analyzed the degrees of lumbar lor- dosis for the sagittal correction and the degrees of the preoperative thoracolumbar kyphosis for the proximal fusion range. For analyzing the usefulness of iliac screws, the subjects were divided into two groups: 1) the -iliac screw (23cases) group for the patients who were fixed without iliac screws and 2) the +iliac screw (12cases) group for the patients who were fixed with iliac screws. Results: There were no patients who had marked anterior pelvic tilt. It is important to correct the lumbar lordosis over 20�compared with the preoperative thoracic kyphosis. There are 10 cases of preoperative thoracolumbar kyphosis ≥ 10�and 25 cases of preoperative thoracolumbar kyphosis < 10�of the total 35 cases. Among 10 cases of preoperative thoracolumbar kyphosis ≥ 10� , 4 cases that were fixed to T10 had no sagit- tal correction loss, and 2 of the 6 cases that were fixed to T11 or T12 had sagittal correction loss. For the 25 cases of preoperative thoracolumbar kyphosis < 10� , 5 cases that were fixed to T10 had no sagittal correction loss and 1 of the 20 cases that were

MRI of paraspinal muscles in lumbar degenerative kyphosis patients and control patients with chronic low back pain

To compare lumbar musculature in lumbar degenerative kyphosis (LDK) patients and chronic low-back pain (CLBP) patients. The study group comprised LDK patients (54 women, aged 44-74 years, mean 60 years) and a control group with CLBP (54 women, aged 45-73 years, mean 60 years). The cross-sectional areas (CSA) of psoas, erector spinae, multifidus, and disc, were measured at the L4-L5 level using magnetic resonance imaging (MRI). Lumbar muscularity was expressed as three ratios: the ratio between CSA of psoas, erector spinae, multifidus and CSA of disc (PS:disc, ES:disc, MF:disc). Multifidus and erector spinae atrophy were evaluated at the L3-L4 level and the degree of fatty atrophy was estimated using three grades: mild, moderate, and severe. The shapes of thoracolumbar fascia were analysed at the L5-S1 level and were classified as flat or convex. Lumbar muscularity was found to be significantly smaller (p<0.001) in LDK patients (PS:disc=0.79, SD 0.22; ES:disc=1.36, SD 0.49; MF:disc=0.55, SD 0.21) than the control group patients (PS:disc=0.98, SD 0.23; ES:disc=1.71, SD 0.46; MF:disc=0.86, SD 0.30). Patients with LDK had a higher proportion of fat deposits in the multifidus and erector spinae muscle (p<0.001), and the thoracolumbar fascia at the L5-S1 level was more commonly flat (p<0.01). Evaluation of paraspinal musculature should be considered when assessing MRI images of the lumbar spine. Measurement of the CSA, visual grading of fatty atrophy and the assessment of the fascia may help physician and radiologist reach a more confident diagnosis for the patients with clinically suspicious LDK.

Correlations between the Cross-Sectional Area and Moment Arm Length of the Erector Spinae Muscle and the Thickness of the Psoas Major Muscle as Measured by MRI and the Body Mass Index in Lumbar Degenerative Kyphosis Patients

Purpose: Lumbar degenerative kyphosis (LDK) is a subgroup of the flatback syndrome, which is a condition caused by spinal degeneration. LDK is reported to be the most frequent cause of lumbar spine deformity in the farming districts of the ‘oriental’ countries. We investigated the relationship between the cross-sectional area (CSA) and the moment arm length (MAL) of the erector spinae muscle and the thickness of the psoas major muscle (PT) and the body mass index (BMI) by performing statistical analysis, and we tried to show the crucial role of these variables for diagnosing LDK. Materials and Methods: From July 2004 to April 2005, we retrospectively reviewed 17 LDK patients who had undergone anterior lumbar interbody fusion (ALIF) with posterior stabilization. We measured both the CSA & MAL on the transverse cross-sectional MR image of the trunk at the fourth to fifth vertebrae (L4/5). The MAL was defined as the anterior-posterior distance between the center of the erector spinae muscle and that of the vertebral body. A comparative study was undertaken between the LDK group and the matched (according to age & gender) control group with regard to the CSA, MAL, PT and BMI. Results: The 17 LDK patients were all females [age: 62.5±4.93 years, height: 157±6.19 cm, weight: 55.59±4.7 kg, and BMI: 22.58±2.08 kg/m 2 ]. The control group patients were all females [age: 63.6±2.27 years, height: 156±5.05 cm, weight: 59.65±7.39 kg and BMI: 24.38 ±2.94 kg/m 2 ]. Spearman’s rho indicated a positive association between the CSA & BMI (rho=0.49, p=0.046), between the MAL & BMI (rho=0.808, p=0.000) and between the CSA & PT (rho=0.566, p=0.018) in the LDK patients. In terms of the CSA versus MAL, there was a positive association in both groups (rho=0.67, p=0.000, MAL=0.023CSA+5.454 in the LDK group; rho=0.564, p=0.018, MAL=0.02CSA+5.832 in the control group with using linear regression analysis). Independent t-tests revealed that both groups had statistically different mean values (p=0.000) in terms of the CSA & MAL. Conclusion: This study showed that the patients with LDK not only had atrophied erector spinae muscles, but also atrophied psoas major muscles and short MALs, which is harmful because of the increased lower back load in the aged patients. Along with BMI, measurement of the CSA, MAL & PT on the MR images provides an objective assessment of the dimension & severity of the muscle atrophy in the LDK patients.