Paraspinal Area Research Articles

Relation of Deep Paraspinal Muscles' Cross-Sectional Area of the Cervical Spine and Bone Union in Anterior Cervical Decompression and Fusion: A Retrospective Study

In the cervical spine, deep paraspinal muscles (DPMs) function to preserve spinal stability and mobility. However, the relationship between DPMs and bone union after cervical fusion surgery has not yet been investigated. The objective of this study is to evaluate the relationship between the cross-sectional area (CSA) of DPMs and bone union after cage alone anterior cervical decompression and fusion (ACDF). A total of 243 patients who underwent cage alone ACDF at the C5-6 or C6-7 segments were enrolled. The CSAs of the longus colli (LCo), longus capitis (LCa), semispinalis cervicis (SSC), and multifidus (MF) were measured using preoperative magnetic resonance imaging at 3 segments. Bone union was evaluated using dynamic radiographs. The patients were divided into 2groups according to the presence of bone union and the fusion time. For the extensor (SSC and MF) CSAs, 4 and 3 segments were significantly different between the union and nonunion groups, and between the 1- and 2-union groups (all P values <0.05), respectively. The CSAs of the extensors at C5-6 were an independent factor for decreasing the possibility of nonunion in men and women (odds ratio, 0.788 and 0.699, respectively; all P values <0.05). In addition, for the standardized extensor CSAs, the C5-6 segment was significantly different between the union and nonunion groups (P values <0.05). Pearson analysis revealed that the extensor CSAs exhibited a significant negative correlation with the fusion time at 5 out of the 6segments (all P values <0.05). The extensor CSAs were related to fusion rate and timing. In particular, as the extensor CSAs increased, fusion timing decreased.

Alteration of Signal Intensity on Follow-Up Magnetic Resonance Imaging in Spinal Epidural Inflammatory Myofibroblastic Tumor: A Case Report and Literature Review

: Inflammatory myofibroblastic tumor (IMT) in the spine or paraspinal area is extremely rare. Here, we report a rare case of a 56-year-old man who had pathological-proven spinal epidural IMT showing a malignancy-like infiltrative feature on MR imaging with alteration of T2 signal intensity on follow-up from slightly high to low compared with initial MR imaging. To the best of our knowledge, this is the first report to describe paraspinal IMT monitoring with various imaging modalities without treatment. From this case, we were able to gain understanding of the natural course of IMT, and it could be helpful in the differential diagnosis of infiltrative paraspinal masses.

Heritability of Thoracic Spine Curvature and Genetic Correlations With Other Spine Traits: The Framingham Study.

Hyperkyphosis is a common spinal disorder in older adults, characterized by excessive forward curvature of the thoracic spine and adverse health outcomes. The etiology of hyperkyphosis has not been firmly established, but may be related to changes that occur with aging in the vertebrae, discs, joints, and muscles, which function as a unit to support the spine. Determining the contribution of genetics to thoracic spine curvature and the degree of genetic sharing among co-occurring measures of spine health may provide insight into the etiology of hyperkyphosis. The purpose of our study was to estimate heritability of thoracic spine curvature using T4 -T12 kyphosis (Cobb) angle and genetic correlations between thoracic spine curvature and vertebral fracture, intervertebral disc height narrowing, facet joint osteoarthritis (OA), lumbar spine volumetric bone mineral density (vBMD), and paraspinal muscle area and density, which were all assessed from computed tomography (CT) images. Participants included 2063 women and men in the second and third generation offspring of the original cohort of the Framingham Study. Heritability of kyphosis angle, adjusted for age, sex, and weight, was 54% (95% confidence interval [CI], 43% to 64%). We found moderate genetic correlations between kyphosis angle and paraspinal muscle area (ρˆG , -0.46; 95% CI, -0.67 to -0.26), vertebral fracture (ρˆG , 0.39; 95% CI, 0.18 to 0.61), vBMD (ρˆG , -0.23; 95% CI, -0.41 to -0.04), and paraspinal muscle density (ρˆG , -0.22; 95% CI, -0.48 to 0.03). Genetic correlations between kyphosis angle and disc height narrowing (ρˆG , 0.17; 95% CI, -0.05 to 0.38) and facet joint OA (ρˆG , 0.05; 95% CI, -0.15 to 0.24) were low. Thoracic spine curvature may be heritable and share genetic factors with other age-related spine traits including trunk muscle size, vertebral fracture, and bone mineral density. © 2016 American Society for Bone and Mineral Research.

Changes in deep lumbar stabilizing muscle thickness by transcutaneous neuromuscular electrical stimulation in patients with low back pain.

Transcutaneous neuromuscular electrical stimulation (NMES) is known to stimulate contraction of deep lumbar stabilizing muscles. The purpose of this study was to investigate changes in deep lumbar stabilizing muscle thickness during transcutaneous NMES on specific abdominal wall and paraspinal regions. Thirty patients with low back pain (LBP) were recruited. Three sessions were preformed: Session 1: NMES on abdominal wall, Session 2: NMES on lumbar paraspinal area, and Session 3: concurrent NMES on abdominal wall and lumbar paraspinal area. Real time ultrasound imaging (RUSI) of three abdominal stabilizing muscles; transverse abdominis (TrA), obliquus internus (OI), obliquus externus (OE) muscles and one posterior stabilizer, the lumbar multifidus muscles (LM) was captured. All studied muscles of TrA, OI, OE, and LM were found to have significant thickness increases during all three sessions compared to resting state (p < 0.05). Thicknesses changes of TrA, OI, and LM were significant during simultaneous NMES of both abdominal wall and lumbar paraspinal regions (Session 3) (p < 0.05). Our results indicate that concurrent NMES on abdominal wall and lumbar paraspinal area is most effective to maximally activate deep lumbar stabilizers. Rehabilitative efforts for patients with LBP may benefit from simultaneous transcutaneous NMES of abdominal and lumbar regions.

Feasibility for Measuring Transverse Area Ratios and Asymmetry of Lumbosacral Region Paraspinal Muscles in Working Dogs Using Computed Tomography.

Describe computed tomographic (CT) anatomy of canine lumbosacral (LS) paraspinal muscles, a method for measuring paraspinal muscle transverse area ratios and asymmetry using CT, and application of this method in a small sample of working dogs with versus without LS pain. Published anatomy references and atlases were reviewed and discrepancies were resolved by examination of anatomic specimens and multiplanar reformatted images to describe transverse CT anatomy of LS region paraspinal muscles. Sixteen Belgian malinois military working dogs were retrospectively recruited and assigned to LS pain positive versus negative groups based on medical record entries. A single observer unaware of dog group measured CT transverse areas of paraspinal muscles and adjacent vertebral bodies, in triplicate, for L5-S1 vertebral locations. A statistician compared muscle transverse area ratios and asymmetry at each vertebral location between groups. The relative coefficient of variation for triplicate CT area measurements averaged 2.15% (N = 16). Multifidus lumborum (L6-7), psoas/iliopsoas (L5-6, L6-7), and sacrocaudalis dorsalis lateralis (L6-7, L7-S1) transverse area ratios were significantly smaller in dogs with LS pain (n = 11) versus without LS pain (n = 5) (p ≤ 0.05). Muscle asymmetry values were not significantly greater in dogs with versus without LS pain. Computed tomographic morphometry of LS region paraspinal muscles is a feasible objective method for use in future evidence-based research studies in working dogs. Potential future research applications include determining whether decreased paraspinal muscle area ratios and/or increased paraspinal muscle asymmetry could be used as markers for preclinical LS pain in stoic dogs or risk factors for other injuries in high performance canine athletes, or determining whether core muscle strengthening exercise prescriptions for dogs with LS pain have an effect on paraspinal muscle area ratios and asymmetry.

Paraspinal muscle, facet joint, and disc problems: risk factors for adjacent segment degeneration after lumbar fusion

Background ContextAdjacent segment degeneration (ASD) is one of the major complications after lumbar fusion. Several studies have evaluated the risk factors of ASD. Although the paraspinal muscles play an important role in spine stability, no study has assessed the relationship between paraspinal muscle atrophy and the incidence of ASD after lumbar fusion. PurposeIn the present study, we aimed to verify the known risk factors of ASD, such as body mass index (BMI), preoperative adjacent facet joint degeneration, and disc degeneration, and to assess the relationship between paraspinal muscle atrophy and ASD. Study DesignThis is a retrospective 1:1 pair analysis matched by age, sex, fusion level, and follow-up period. Patient SampleTo calculate the appropriate sample size for the study, we performed a pre-study analysis of the paraspinal muscle cross-sectional area (CSA), and estimated that at least 35 cases would be needed for each group. Among the 510 patients who underwent posterior lumbar fusion for degenerative lumbar disease between January 2009 and October 2009, a total of 50 patients with ASD after surgery were selected. Another group of 50 matched patients with degenerative lumbar disease without ASD after spinal fusion were selected as the control group. Each patient in the ASD group was matched with a control patient according to age, sex, fusion level, and follow-up period. Outcome MeasuresRadiographic measurements and demographic data were reviewed. MethodsThe risk factors considered were higher BMI, preoperative adjacent segment disc and facet degeneration, and preoperative paraspinal muscle atrophy and fatty degeneration. The radiographic data were compared between the ASD and control groups to determine the predictive factors of ASD after posterior lumbar fusion by using logistic regression analysis. The study was not externally funded. The authors have no conflict of interest to declare. ResultsMultivariate logistic regression analysis indicated that higher BMI (odds ratio [OR]: 1.353, p=.008), preoperative facet degeneration on computed tomography examination (OR: 3.075, p=.011), disc degeneration on magnetic resonance imaging (MRI) (OR: 2.783, p=.003), fatty degeneration (OR: 1.080, p=.044), and a smaller relative CSA of the paraspinal muscle preoperatively (OR: 0.083, p=.003) were significant factors for predicting the development of ASD. ConclusionsThe occurrence of radiological ASD is most likely multifactorial, and is associated with a higher BMI, preexisting facet and disc degeneration on preoperative examination, and a smaller preoperative relative CSA of the paraspinal muscle on MRI.

WISE 2005: Aerobic and resistive countermeasures prevent paraspinal muscle deconditioning during 60-day bed rest in women.

Microgravity-induced lumbar paraspinal muscle deconditioning may contribute to back pain commonly experienced by astronauts and may increase the risk of postflight injury. We hypothesized that a combined resistive and aerobic exercise countermeasure protocol that included spinal loading would mitigate lumbar paraspinal muscle deconditioning during 60 days of bed rest in women. Sixteen women underwent 60-day, 6° head-down-tilt bed rest (BR) and were randomized into control and exercise groups. During bed rest the control group performed no exercise. The exercise group performed supine treadmill exercise within lower body negative pressure (LBNP) for 3-4 days/wk and flywheel resistive exercise for 2-3 days/wk. Paraspinal muscle cross-sectional area (CSA) was measured using a lumbar spine MRI sequence before and after BR. In addition, isokinetic spinal flexion and extension strengths were measured before and after BR. Data are presented as means ± SD. Total lumbar paraspinal muscle CSA decreased significantly more in controls (10.9 ± 3.4%) than in exercisers (4.3 ± 3.4%; P < 0.05). The erector spinae was the primary contributor (76%) to total lumbar paraspinal muscle loss. Moreover, exercise attenuated isokinetic spinal extension loss (-4.3 ± 4.5%), compared with controls (-16.6 ± 11.2%; P < 0.05). In conclusion, LBNP treadmill and flywheel resistive exercises during simulated microgravity mitigate decrements in lumbar paraspinal muscle structure and spine function. Therefore spaceflight exercise countermeasures that attempt to reproduce spinal loads experienced on Earth may mitigate spinal deconditioning during long-duration space travel.

Malignant rhabdoid tumor of the vulva: A case report and review of the literature

Malignant rhabdoid tumor was originally described in the kidney as a variant of Wilms' tumor in 1978 by Beckwith and Palmer [1]. Extrarenal forms of this tumor are very rare but have been described in a variety of sites including soft tissues, paraspinal and paratesticular areas, the central nervous system, colon, tongue, prostate, liver, skin, thymus, heart, pelvis, uterus, and vulva. Only 13 vulvar cases have been reported thus far in the English literature. We are reporting the 14th case and a review of the clinical features, management and prognosis of all cases. A 51-year-old G4P3, postmenopausal woman presented to our Obstetrics and Gynecology Clinic, Erciyes University Faculty of Medicine, Kayseri, Turkey with a painless vulvar mass measuring 3 cm that was situated on the left labium major adjacent to the anterior comissura. The lesion first appeared 2 months previously and was locally excised by a gynecologist at a secondary care center with the presumed diagnosis of lipoma. The histopathological examination revealed an extrarenal rhabdoid tumor (ERT). At the time of referral to our center, 20 days after the excision, a recurrent tumor measuring 4 cm, which was painless, with irregular border and arising from the excision site was detected (Figure 1). On transvaginal ultrasonography, the uterus, endometrial thickness, and both ovaries were normal. A positron emission tomography/ computer tomography with 18-F-fludeoxyglucose (18-F-FDG PET/CT) was performed for metastases screening. The 18-F-FDG PET/CT detected a soft-tissue lesion showing hypermetabolic

Thrombosis of the inferior vena cava presenting with findings of radiculopathy

The patient presented to our clinic with lumbar pain and numbness in the right foot, as well as inguinal and thigh pain during walking. Previous orchiectomy due to germ cell testis tumor was present in the medical history. Lumbar magnetic resonance imaging with a preliminary diagnosis of disc herniation revealed no intervertebral disk pathology, but para-aortic-paracaval lymphadenopathies were observed. A heterogeneous, hyperintense structure containing septation and segmental widening was observed in the location of inferior vena cava (IVC). This was compatible with chronic thrombosis filling the lumen of the IVC at contrast-enhanced computed tomography, and the diagnosis was confirmed with Doppler ultrasonography. Computed tomography also revealed collateral dilated venous structures in the inguinal region and paraspinal area. Magnetic resonance imaging showed that dilated collateral venous structures were in the left foraminal localization, and they were compressing the nerve roots at the levels of L1–L2 and L2–L3 (Fig. 1).

Charcot spine neuroarthropathy and hip heterotopic ossification

Charcot spine neuroarthropathy and heterotopic ossification (HO) are known complications of complete spinal cord injury. Heterotopic ossification occurs most frequently around the hip joint. The clinical significance of HO ranges from an incidental finding on radiographs to total ankylosis leading to severely limited range of motion [1,2]. A 54-year-old man with complete T10 spinal cord injury for 34 years was admitted to the authors’ institution with left distal femur fracture. Plain radiograph of the left hip showed severe HO (Fig. 1). Plain radiograph of the spine showed spine dislocation at L3–L4 with osteolysis of the L3 and L4 vertebral bodies (Fig. 2). Computed tomography scan of the spine showed three-column body destruction and bony debris in the paraspinal area characteristic of Charcot spine neuroarthropathy (Fig. 3).

A 20-Year-Old Retained Surgical Gauze Mimicking a Spinal Tumor: A Case Report.

A 79-year-old man visited our clinic complaining of lower back and left leg radiating pain that began 1 month prior to his presentation. He underwent surgery for lumbar disc herniation 20 years ago at another hospital. Magnetic resonance imaging revealed left-sided foraminal stenosis at L4-5. In addition, a paraspinal mass occupying the L4 spinous process and left lamina was observed. We subsequently performed an L4-5 decompression and fusion. During the operation, retained surgical gauze with granulation tissue was found. The term gossypiboma is used to define a mass lesion consisting of retained surgical gauzes and an adjacent foreign body reaction. Gossypibomas are uncommon in the paraspinal area and are mostly asymptomatic in chronic cases. Because there are no specific clinical or radiological signs, they can be confused with other tumorous conditions. Gossypibomas should be included in the differential diagnosis of paraspinal soft-tissue masses detected in patients with a history of prior spinal surgery.

Thoracic Radiculopathy due to Rare Causes.

Thoracic radiculopathy represents an uncommon spinal disorder that is frequently overlooked in the evaluation of thoracic, or abdominal pain syndrome. The clinical representation of this uncommon disorder is often atypical. With many differential diagnoses to consider, it is not surprising that the cause of thoracic radiculopathy is often not discovered for months, or years, after the symptoms arise. We report two rare cases of thoracic radiculopathy; one case was caused by extraskeletal Ewing sarcoma (EES) along the thoracic paraspinal area, and the other by foraminal stenosis, due to a bony spur of the thoracic vertebra. As such, thoracic radiculopathy should be considered in the diagnosis of patients with thoracic and abdominal pain, especially if initial diagnostic studies are inconclusive.

Spinous Process Osteochondroma as a Rare Cause of Lumbar Pain.

We present a case of a 5th Lumbar Vertebra (L5) spinous process osteochondroma as a rare cause of lumbar pain in an old patient. A 70-year-old male presented with progressive and disabling lower lumbar pain. Tenderness over the central and left paraspinal area of the lower lumbar region and a palpable mass were evident. CT scan showed a mass arising from the spinous process of L5. Marginal resection of the tumor was performed through a posterior approach. The histological study revealed an osteochondroma. After surgery, pain was completely relieved. After one year there was no evidence of local recurrence or symptoms. Osteochondromas rarely involve the spine, but when they do symptoms like pain, radiculopathy/myelopathy, or cosmetic deformity may occur. The imagiologic exam of election for diagnosis is CT scan. When symptomatic the treatment of choice is surgical resection. The most concerning complication of osteochondromas is malignant transformation, a rare event.

Bee venom apipuncture; a successful therapy for myofascial pain. A case based review

A 58 years old man with widespread myofascial pain in dorsa lumbar paraspinal area and shoulder girdle muscles received whole bee venom injections (apipuncture) on trigger points and acupoint of Kid 3- 10, Ren 2-4 and UB 25. Before apipuncture injections intradermal allergy tests were performed. Patient experienced pain reduction at least 60 % following venom injections as measured by VAS, verbal description for pain intensity and unpleasantness, palpable muscle firmness and pressure pain thresholds. Bee venom which blocks muscle contraction by inhibiting nociceptive sensory impulses, appears to be an effective treatment on focal myofascial pain syndromes.

Myxoid Dermatofibrosarcoma Protuberance Presented as a Mass over Right Paraspinal Area of Back

Myxoid Dermatofibrosarcoma Protuberance Presented as a Mass over Right Paraspinal Area of Back

Study of Outcome of an Implanted Autologous Auricular Cartilage: A Preliminary Experimental Research in Rabbits.

To investigate the viability of the implanted crushed and uncrushed auricular cartilage graft with intact perichondrium with respect to macroscopic and microscopic parameters. Cartilage grafts from 8 white New Zealand rabbits were harvested from the right auricle, with intact perichondrial layers. There were two categories Pre implant and Post-implant and two types, mildly crushed and uncrushed cartilage graft. The cartilage grafts were implanted into the subcutaneous pockets over the right upper paraspinal area. At the end of 2months, implanted grafts were retrieved and examined histopathologically. There was a difference among the both types of cartilages in both the categories with respect to chronic inflammation, fibrosis, cartilage mass viability and vascularization. The mildly crushed auricular autologous cartilage with intact perichondrium does not lose the viability and maintains the structural integrity and thus increasing the clinical predictability for cosmetic correction of nose in rhinoplasty.

Associations of Abdominal Muscle Area with 4-Year Change in Coronary Artery Calcium Differ by Ethnicity Among Post-Menopausal Women.

To examine the association of abdominal muscle area with coronary artery calcium (CAC) presence, extent, and progression in a multi-ethnic cohort of older, community-dwelling post-menopausal women. Cross-sectional and longitudinal population-based cohort. The sample comprised 179 non-Hispanic White women, 116 Filipina women and 144 African American women, all without known CVD, who underwent chest and abdominal computed tomography (CT) scans twice about four years apart for abdominal muscle and fat, as well as CAC. CAC presence, extent and progression. There was a significant interaction of ethnicity with baseline oblique muscle area (p-for-interaction .01), and marginally significant interactions with baseline total and paraspinal muscle for change in CAC (p-for-interactions both .09). Among Filipina women, each standard deviation (SD) greater total muscle area was associated with a 26% (95% CI (-43%, -4%), P=.02) reduced rate of change in CAC; higher paraspinal and oblique muscle area were associated with a 24% (-38%, -6%, P=.01) and a 37% (-53%, -16%, P=.0002) reduced rate of change in CAC, respectively. These associations were not significant in African American or non-Hispanic White women. There were no significant associations of abdominal muscle with CAC presence or extent, nor were there significant ethnicity by muscle interactions in these models. Among Filipina women, greater abdominal muscle mass is associated with a decreased rate of CAC progression. Higher muscle mass may be important for this group in reducing CVD outcomes.

Morphometrics as a predictor of perioperative morbidity after lumbar spine surgery.

OBJECT Improved objective assessments of perioperative risk after spine surgery are necessary to decrease postoperative morbidity and mortality rates. Morphometric analysis has proven utility in predicting postoperative morbidity and mortality in surgical disciplines. The aim of the present study was to evaluate whether morphometrics can be applied to the cases of patients undergoing lumbar spine surgery. METHODS The authors performed a retrospective review of the perioperative course of 395 patients who underwent lumbar surgery at their institution from 2013 to 2014. Preoperative risk factors such as age, diabetes, smoking, coronary artery disease, and body mass index (BMI) were recorded. Preoperative MRI was used to measure the psoas muscle area at the L-4 vertebra and paraspinal muscle area at the T-12 vertebra. Primary outcomes included unplanned return to the operating room, 30- and 90-day readmissions, surgical site infection, wound dehiscence, new neurological deficit, deep vein thrombosis, pulmonary embolism, myocardial infarction, urinary tract infection, urinary retention, hospital-acquired pneumonia, stroke, and prolonged stay in the intensive care unit. RESULTS The overall rate of adverse events was 30%, the most common event being urinary retention (12%). Greater age (p = 0.015) and tobacco usage (p = 0.026) were both significantly associated with complications for all patients, while diabetes, coronary artery disease, and high BMI were not. No surgery-related characteristics were associated with postoperative morbidity, including whether surgery required instrumentation, whether it was a revision, or the number of vertebral levels treated. Using multivariate regression analysis, male and female patients with the lowest psoas tertile had an OR of 1.70 (95% CI 1.04-2.79, p = 0.035) for having postoperative complications. Male patients in the lowest psoas tertile had an OR of 2.42 (95% CI 1.17-5.01, p = 0.016) for having a postoperative complication. The paraspinal muscle groups did not provide any significant data for postoperative morbidity, even after multivariate analysis. CONCLUSIONS The morphometric measurement of psoas muscle size may be a sensitive predictive tool compared with other risk factors for perioperative morbidity in male patients undergoing lumbar surgery.

Thinking Outside the Bowels: An Atypical Cause of Acute Abdominal Pain

Introduction: Isolated spontaneous celiac artery dissection is an extremely rare entity with its occurrence without aortic dissection even rarer. We report a case of isolated spontaneous celiac artery dissection in the absence of autoimmune disease. Case Presentation: A 48-year-old male with a past medical history of migraines presents with acute, severe, persistent epigastric pain with radiation to the left upper quadrant and left paraspinal area. Cross sectional imaging performed reveals celiac artery dissection (Figure 1) without signs of an underlying vasculitis. An extensive rheumatologic evaluation undertaken was unremarkable with the only laboratory abnormality being a mildly elevated lipase level. Given his concomitant history of headaches, a temporal artery biopsy obtained was unrevealing. Blood cultures and ECHO were unremarkable for signs of thromboembolic disease and abdominal pain did not resolve with empiric trial of systemic steroids. Interval CT angiogram 2 weeks after presentation reveals no change in dissection; at this juncture, a diagnosis of isolated spontaneous celiac artery dissection was made with anticoagulation commenced and resultant clinical and radiological improvement observed (Figure 1).Figure 1Conclusion: Isolated spontaneous celiac artery dissection is a rare phenomenon with the exact etiology and natural history to date remaining an enigma. Ideal treatment modalities still remain to be clearly defined with anticoagulation, stent placement, and surgery employed. Our case demonstrates the efficacy of medical management in such a rare condition.

Lumbar paraspinal muscle transverse area and symmetry in dogs with and without degenerative lumbosacral stenosis.

To investigate whether dogs with degenerative lumbosacral stenosis have decreased lumbar paraspinal muscle transverse area and symmetry compared with control dogs. Retrospective cross-sectional study comparing muscles in transverse T2-weighted magnetic resonance images for nine dogs with and nine dogs without degenerative -lumbosacral stenosis. Mean transverse area was measured for the lumbar multifidus and sacrocaudalis dorsalis lateralis muscles bilaterally and the L7 vertebral body at the level of the caudal endplate. Transverse areas of both muscle groups relative to L7 and asymmetry indices were compared between study populations using independent t tests. Mean muscle-to-L7 transverse area ratios were significantly smaller in the degenerative lumbosacral stenosis group compared with those in the control group in both lumbar multifidus (0·84 ±0·26 versus 1·09 ±0·25; P=0·027) and sacrocaudalis dorsalis lateralis (0·5 ±0·15 versus 0·68 ±0·12; P=0·005) muscles. Mean asymmetry indices were higher for both muscles in the group with degenerative lumbosacral stenosis than in the control group, but highly variable and the difference was not statistically significant. These findings suggest that dogs with degenerative lumbosacral stenosis have decreased lumbar paraspinal muscle mass that may be a cause or consequence of the -syndrome. Understanding altered paraspinal muscle characteristics may improve understanding of the -pathophysiology and management options for degenerative lumbosacral stenosis.