Are there compartment syndromes in some patients with idiopathic back pain?

Lumbar Paraspinal Compartment Syndrome: Case Report and Critical Evaluation of the Literature

BACKGROUND

Lumbar compartment syndrome is a recognized clinical phenomenon, despite receiving less attention as a clinical entity. Given its rarity, the definitive presentation, diagnosis, and management strategies are not completely agreed upon.

MATERIALS AND METHODS

A literature search on PubMed of all case reports of lumbar paraspinal compartment syndromes was conducted. All case reports and reviews were analyzed for patient demographic data, presentation, diagnostic evaluation, treatment, and clinical follow-up.

RESULTS

A total of 37 cases of lumbar compartment syndrome were identified. Overall, 91.9% occurred in men with an average age of 30.9 years. Weightlifting (n=18, 48.6%) and physical exertion (n=7, 18.9%) accounted for the majority of presentations. In all, 37.8% of cases occurred unilaterally. Creatinine kinase, aspartate aminotransferase, and alanine aminotransferase were notably elevated. Compartment pressure was elevated with an average of 91.8 mm Hg (SD: 44.8 mm Hg). Twenty-two cases were treated operatively (59.5%) and 15 (40.5%) were treated nonoperatively. In total, 19/20 (95.0%) of cases treated operatively reported either resolution of pain or return to baseline activities without limitation, compared with 1/11 (9.1%) treated nonoperatively. This difference between the operative and nonoperative cohort was statistically significant ( P <0.0001).

CONCLUSIONS

Lumbar paraspinal compartment syndrome is a rare, but well-documented clinical entity. In all, 67.5% of cases occurred after weightlifting or physical exertion. Overall, 40.5% of cases in the literature were treated nonoperatively. Per our analysis, there is a clinically and statistically significant difference in cases treated operatively versus nonoperatively (95.0% vs. 9.1%, P <0.0001).

The Relationship between Exercise-Induced Low Back Pain, the Fat Infiltration Rate of Paraspinal Muscles, and Lumbar Sagittal Balance

Introduction

Exercise-induced low back pain (EILBP) is induced during anterior trunk tilting when walking or prolonged standing. In some elderly with chronic LBP, the pain is induced by EILBP. The paraspinal muscles play an important role in supporting the spine; therefore, a dysfunction of back muscles and kyphotic alignment are considered to be associated with EILBP. However, few reports are showing the relationship between EILBP and degenerative muscle changes. This study aimed to clarify the relationship between EILBP, degenerative changes of paraspinal muscles, and spinal alignment in an epidemiological study.

Methods

A total of 324 subjects were included in the analysis. The presence of EILBP was determined through a medical interview and physical examination. The subjects underwent lumbar spine magnetic resonance image (MRI) and X-ray. The fat infiltration rate (FIR) of the multifidus, erector spinae, and psoas major were analyzed using MRI. For lumbar sagittal balance, L1 axis S1 distance (LASD) was measured using X-ray images. Multivariate logistic regression analysis was used to analyze the association between the presence of EILBP and FIR or LASD.

Results

The prevalence of EILBP was 21% and it increased with age. The subjects with EILBP had statistically higher FIR of the multifidus, erector spinae, and psoas major than those without EILBP. There was a significant association between the presence of EILBP and higher FIR of the erector spinae at L1-2 and L5-S1 (p<0.05). However, there were no significant associations between EILBP and LASD.

Conclusions

According to the results in this study, EILBP is not rare and the FIR of the erector spinae is associated with the presence of EILBP.

Minimally Invasive Percutaneous Fasciotomy in Lumbar Paraspinal Compartment Syndrome: A Case Report and Review of Literature

CASE

Lumbar paraspinal compartment syndrome (LPCS) is a rare but potentially catastrophic pathology caused by increased intracompartmental pressures leading to potential ischemic necrosis of muscle, local denervation, and complications of rhabdomyolysis. A combination of unique clinical history and examination findings, laboratory findings, and radiologic imaging help in diagnosis.

CONCLUSION

Early detection and intervention with minimally invasive percutaneous fasciotomy can minimize local soft tissue trauma while providing extensive fascial release with good clinical outcomes. Radiographic follow-up in this case suggests that the muscle at risk in LPCS can be spared with early surgical intervention.

Paravertebral compartment syndrome after exercise: a case report

BACKGROUND

Paravertebral compartment syndrome occurring without trauma is quite rare. We report a case of compartment syndrome that occurred after spinal exercises.

CASE PRESENTATION

A 23-year-old Japanese rower developed severe back pain and was unable to move 1 day after performing exercises for the spinal muscles. Initial evaluation at a nearby hospital revealed hematuria and elevated creatine phosphokinase levels. He was transferred to our hospital, where magnetic resonance imaging revealed no hematoma but confirmed edema in the paravertebral muscles. The compartment pressure measurements were elevated bilaterally. Despite his pain being severe, his creatine phosphokinase levels were expected to peak and decline; his urine output was normal; and surgery was undesirable. Therefore, we opted for conservative management. The next day, the patient's compartment pressure diminished, and his pain levels decreased to 2/10. After 5 days, he was able to walk without medication.

CONCLUSIONS

We present a rare case of compartment syndrome of the paravertebral muscles with good resolution following conservative management. We hope our case findings will help avoid unnecessary surgery in cases of paravertebral compartment syndrome.

Comparing two posterior quadratus lumborum block approaches with low thoracic erector spinae plane block: an anatomic study

BACKGROUND AND OBJECTIVES

Both posterior quadratus lumborum (QL) and erector spinae plane (ESP) blocks have been described as new truncal interfascial plane blocks. Distribution of injectate is influenced by fascial anatomy; therefore, different injection sites may produce similar spread. This anatomic study was designed to test the hypothesis that a posteromedial QL block at L2 level will more closely resemble a low thoracic ESP block when compared with the posterolateral approach at L2 level.

METHODS

Left-sided ESP blocks were performed in six cadavers at T10-11. Three of these cadavers received right-sided posteromedial QL block at L2, while the other three received right-sided posterolateral QL block at L2. All injections were composed of 20 mL methylcellulose 0.5 % mixed with India ink and 10 mL of Omnipaque (Iohexol) 240 mg/mL. CT 24 hours after injection and cadaver dissection were used to evaluate injectate spread.

RESULTS

Cephalocaudal spread of injectate by CT and cadaveric dissection was highly correlated (r=0.85 [95% CI 0.51 to 0.95]). Cadaver dissection showed ESP injectate spread deep to the muscle (mean [SD]) 11.7 (2.3) levels compared with 7.3 (1.2) levels for posterolateral QL and 9.7 (1.5) for posteromedial QL (p=0.04 overall, with a statistically significant pairwise difference between ESP and posterolateral QL only). The subcostal nerve and dorsal rami were commonly involved in most blocks, but the paravertebral space and ventral rami had inconsistent involvement. The lumbocostal ligament limited cranial spread from the posterlateral QL block approach.

CONCLUSIONS

The posteromedial QL block at L2 produces more cranial spread beyond the lumbocostal ligament than the posterolateral QL block, and this spread is comparable with a low thoracic ESP block. Both posterior QL and ESP blocks show unreliable spread of injectate to the paravertebral space and ventral rami, but the dorsal rami were frequently covered.

Low Back Pain in Patients with Lumbar Spinal Stenosis-Hemodynamic and electrophysiological study of the lumbar multifidus muscles

Introduction

Several studies have demonstrated improvement in low back pain (LBP) after decompression surgery for lower extremity symptoms in lumbar spinal stenosis (LSS); however, the influence of neuropathic disorders on LBP is uncertain. Aim of this study is to identify the features of motion-induced and walking-induced LBP in patients with LSS and to assess whether neuropathic LBP develops.

Methods

In total, 234 patients with LSS including L4/5 lesion were asked to identify their LBP. Subjects were classified into three groups: walking-induced LBP that aggravated during walking (W group), motion-induced LBP that aggravated during sitting up (M group), and no LBP (N group). Cross-sectional areas of the dural sac, lumbar multifidus, and the erector spinae were measured. Intramuscular oxygenation was evaluated with near-infrared spectrophotometer. Surface electromyography (EMG) and mechanomyography (MMG) were performed on the lumbar multifidus. Morphological, hemodynamic, and electrophysiological differences in the onset of LBP were evaluated.

Results

The prevalence of W, M, and control groups was 31.2%, 32.1%, 36.8%, respectively. Concordance between the laterality of LBP and leg symptoms including pain and numbness was 86.3% in the W group and 47.0% in the M group. Dural sac area was lower in the W group than in the M and control groups. In the hemodynamic evaluation, the oxygenated hemoglobin level was significantly lower in the W group than in the M and N groups. In electrophysiological evaluation of lumbar multifidus, the mean power frequency in EMG was significantly higher in the W group than in the N group. Amplitude in MMG was significantly lower in the W group than in the N group.

Conclusions

Neurologic disturbance in patients with LSS may be attributed to “neuropathic LBP.” Neuropathic multifidus disorder plays a role in walking-induced LBP.

Acquired Degenerative Changes of the Intervertebral Segments at and Supradjacent to the Lumbosacral Junction

In earlier evolutionary times, mammals were primarily quadrupeds, although other bipeds have been represented during the course of the Earth's several billion-year history. In many cases, either the bipedal stance yielded a large tail and hypoplastic upper extremities (e.g., Tyrannosaurus rex, the kangaroo), or it culminated in hypoplasia of the tail and further development and specialization of the upper extremities (e.g., nonhuman primates and human beings). In the human species this relatively recently acquired posture resulted in a more or less pronounced lumbosacral lordosis. In turn, certain compensatory anatomic features have since occurred. These include the normal characteristic posteriorly directed wedge-shape of the L5 vertebral body and the L5-S1 intervertebral disc; the L4 vertebral body and the L4-L5 and L3-4 disc may be similarly visibly affected.

These compensatory mechanisms, however, have proved to be functionally inadequate over the present long-term of the human life span. Upright posture leads to increased weight bearing in humans that progressively causes excess stresses at and suprajacent to the lumbosacral junction. These combined factors result in accelerated aging and degenerative changes and a predisposition to frank biomechanical failure of the subcomponents of the spinal column in these spinal segments.

One other specific problem that occurs at the lumbosacral junction that predisposes toward premature degeneration is the singular relationship that exists between a normally mobile segment of spine (i.e., the lumbar spine), and a normally immobile one (i.e., the sacrum). It is well known that mobile spinal segments adjacent to congenitally or acquired fused segments have a predilection toward accelerated degenerative changes. The only segment of the spine in which this is invariably normally true is at the lumbosacral junction (i.e., the unfused lumbar spine adjoining the fused sacrum).

Nevertheless, biomechanical failures of the human spine are not lethal traits; in most cases today, mankind reaches sexual maturity before spinal biomechanical failure precludes sexual reproduction. For this gene-preserving reason, degenerative spinal disorders will likely be a part of modern societies for the foreseeable eternity of the race.

The detailed alterations accruing from the interrelated consequences of and phenomena contributing to acquired degenerative changes of the lumbosacral intervertebral segments as detailed in this discussion highlight the extraordinary problems that are associated with degenerative disease in this region of the spine. Further clinicoradiologic research in this area will progressively determine the clinical applications and clinical efficacy of the various traditional and newer methods of therapy in patients presenting with symptomatic acquired collapse of the intervertebral discs at and suprajacent to the lumbosacral junction and the interrelated degenerative alterations of the nondiscal structures of the spine.

Shorter Lumbar Paraspinal Fascia Is Associated With High Intensity Low Back Pain and Disability

STUDY DESIGN

A cross-sectional, community-based study.

OBJECTIVE

The aim of this study was to investigate the relationship between structural features of the thoracolumbar fascia and low back pain and disability.

SUMMARY OF BACKGROUND DATA

The thoracolumbar fascia plays a role in stabilization of the spine by transmitting tension from the spinal and abdominal musculature to the vertebrae. It has been hypothesized that the fascia is associated with low back pain through the development of increased pressure in the paraspinal compartment, which leads to muscle ischemia.

METHODS

Seventy-two participants from a community-based study of musculoskeletal health underwent Magnetic Resonance Imaging from the T12 vertebral body to the sacrum. The length of the paraspinal fascia and cross-sectional area of the paraspinal compartment were quantitatively measured from axial images at the level of the transverse processes and the Chronic Pain Grade Scale was used to assess low back pain intensity and disability.

RESULTS

A shorter length of fascia around the parapsinal compartment was significantly associated with high intensity low back pain and/or disability, after adjusting for age, gender, and body mass index [right odds ratio (OR) 1.9, 95% CI 0.99-3.8, P = 0.05; left OR 2.6, 95% CI 1.2 to 5.6, P = 0.01). Further adjustment for the cross-sectional area of the compartment strengthened the associations between fascial length and low back pain/or disability (right OR 8.9, 95% CI 1.9-40.9, P = 0.005; left OR 9.6, 95% CI 1.2-42.9, P = 0.003).

CONCLUSION

This study has demonstrated that a shorter lumbar paraspinal fascia is associated with high intensity low back pain and/or disability among community-based adults. Although cohort studies are needed, these results suggest that structural features of the fascia may play a role in high levels of low back pain and disability.

LEVEL OF EVIDENCE

3.

Paravertebral compartment syndrome after training causing severe back pain in an amateur rugby player: report of a rare case and review of the literature

BACKGROUND

Acute compartment syndrome (CS) of the paravertebral muscles without external trauma is rarely reported in literature. Not all of clinical symptoms for CS are applicable to the paravertebral region.

CASE PRESENTATION

A 30-year-old amateur rugby player was suffering from increasing back pain following exertional training specially targeting back muscles. He presented with hardly treatable pain of the lumbar spine, dysaesthesia of the left paravertebral lumbar region as well as elevated muscle enzymes. Magnetic resonance imaging (MRI) showed an edema of the paravertebral muscles. Compartment pressure measurement revealed increased values of 47 mmHg on the left side. Seventy-two hours after onset of back pain a fasciotomy of the superficial thoracolumbar fascia was performed. Immediately postoperatively the clinical condition improved and enzyme levels significantly decreased. The patient started with light training exercises 3 weeks after the operation.

CONCLUSIONS

We present a rare case of an exercise-induced compartment syndrome of the paravertebral muscles and set it in the context of existing literature comparing various treatment options and outcomes. Where there is evidence of paravertebral compartment syndrome we recommend immediate fasciotomy to prevent rhabdomyolysis and further consequential diseases.

Lumbar paraspinal compartment syndrome

The purpose of this study was to systematically review the available evidence on lumbar paraspinal compartment syndrome with specific reference to patient demographics, aetiology, types, diagnosis, clinical features, and treatment. This was an Institutional Review Board-exempt study performed at a Level 1 trauma center. A PubMed search was conducted with the title query: lumbar paraspinal compartment syndrome. Eleven articles met our search criteria. Three of the patients with acute paraspinal compartmental syndrome treated with fasciotomy had a full recovery and were able to resume skiing after four months. The aetiology of the onset of lumbar paraspinal compartment syndrome is broadly divided into acute and chronic. Lumbar paraspinal compartment syndrome is one of the causes of back pain with diagnostic clinical features which should be considered in the differential diagnosis of a patient with low back pain. Prospective multicentre trials may provide the surgeon with more insight into the diagnosis and management of lumbar paraspinal compartment syndrome.

Acute exertional lumbar paraspinal compartment syndrome

STUDY DESIGN

A case report and review of the literature.

OBJECTIVE

To report a rare case of paraspinal compartment syndrome that presented a diagnostic challenge.

SUMMARY OF BACKGROUND DATA

Paraspinal compartment syndrome is a rare condition defined as increased pressure within a closed fibro-osseous space, resulting in reduced blood flow and tissue perfusion in that space. The reduced perfusion causes ischemic pain and irreversible damage to the tissues of the compartment if unrecognized or left untreated.

METHODS

A 20-year-old African-American man presented with 2 days of new-onset progressive back pain after repetitive lifting of 235 lbs in a deadlift exercise. The patient had significantly tender lumbar paraspinal muscles, was unable rise from a supine position, and had severe pain with attempted active rolling or sitting. Findings of supine radiographs were normal. Findings of initial laboratory investigations were consistent with rhabdomyolysis and acute kidney injury. Despite aggressive hydration and narcotic analgesia, the patient's creatinine kinase and myoglobin continued to rise and his pain continued to worsen. Computed tomography of the spine revealed enlarged paraspinal musculature and decreased enhancement bilaterally. Gadolinium-enhanced magnetic resonance imaging of the spine showed increased T2 signal and paraspinal muscle edema with areas of decreased contrast uptake, consistent with ischemia and necrosis. Compartment pressures measured 78 mm Hg on the left and 26 mm Hg on the right.

RESULTS

Because hydration and analgesia had failed, the patient was taken urgently to the operating room for bilateral paraspinal fasciotomies with delayed closure. His symptoms and rhabdomyolysis then resolved during the next 2 days.

CONCLUSION

The diagnostic challenge presented by this case, especially considering the rarity of paraspinal compartment syndrome, indicates the need for a high index of suspicion in the appropriate setting.

Increased intramuscular pressure in lumbar paraspinal muscles and low back pain: model development and expression of substance P in the dorsal root ganglion

STUDY DESIGN

The association between intramuscular pressure and low back pain was investigated by measuring intramuscular pressure and blood flow, assessing histologic appearance, and performing immunohistochemical testing in rats.

OBJECTIVE

To develop an experimental rat model of increased intramuscular pressure (IMP) in the lumbar paraspinal muscles accompanied by reduced intramuscular blood flow (IMBF). The expression of neuropeptides in the dorsal root ganglion of the experimental model was also investigated.

SUMMARY OF BACKGROUND DATA

Studies have reported that IMP in the lumbar paraspinal muscles is one of the causes of chronic low back pain. However, the pathology of low back pain accompanied by IMP has not been sufficiently clarified.

METHODS

A balloon was inflated below the vertebral fascia of rats (balloon group) and intramuscular pressure and blood flow in the lumbar paraspinal muscles were measured. Intramuscular pressure was measured using a pressure transducer, whereas IMBF was measured using a contact-type laser Doppler flowmeter. Compared with the sham operation group, intramuscular pressure was higher and IMBF was lower for the balloon group at 1 hour and 1 day after insertion. In addition, at 1 hour and 1 day after insertion, IMBF and pressure were continuously measured while rats were positioned in flexion for 1 hour.

RESULTS

Intramuscular pressure was significantly higher and IMBF was significantly lower in the balloon group at 1 day after insertion (P < 0.05). Expression of substance P, a neuropeptide, was also observed in the dorsal root ganglion of the first lumbar vertebra.

CONCLUSION

These findings suggest that IMP and decreased IMBF in the lumbar paraspinal muscles induce inflammation and pain in the lower back.

Muscle oxygenation and intramuscular pressure related to posture and load in back muscles

BACKGROUND CONTEXT

There is little information about the simultaneous changes of intramuscular pressure (IMP) and oxygen saturation (StO(2)) of the paraspinal muscle under various conditions of posture and load.

PURPOSE

To measure simultaneously and compare IMP and StO(2) across a range of static trunk postures commonly observed during normal work tasks.

STUDY DESIGN

A prospective study using a repeated-measure design in clinical setting.

PATIENT SAMPLE

Sixteen healthy young men with no history of back pain.

OUTCOME MEASURES

Simultaneous measurements of IMP by a flexible slit catheter and StO(2) by near infrared spectroscopy of the multifidus muscle were performed.

METHODS

The two measures were taken in six static posture tasks: standing upright and bending forward with and without load (20kg), bending backward and during a sustained isometric contraction (ie, Sorensen test). To compare the influence of the tasks on IMP and StO(2) variables, a one-way variance analysis with repeated measures was used. Spearman's rank correlation coefficient (rho) was determined between the two variables for each posture task.

RESULTS

We observed only a moderate but significant correlation between IMP and StO(2) values in upright standing and a trend in bending forward positions with load (p<.05). IMP increased in the bending backward position and showed the greatest increase during the Sorensen test. StO(2) decreased significantly during the Sorensen test, in the bending forward position with and without load bearing but did not in bending backward.

CONCLUSION

The simultaneous recording of IMP and StO(2) of the multifidus muscle allows a deeper insight of physiological events during various trunk postures. In the mutifidus muscle, there is no evident linear relationship between IMP and StO(2) values in various static postures of the trunk in young males. This preliminary study shows that IMP may play a role on StO(2) only in some circumstances, such as a prolonged endurance test or in a bending forward position with a significant load bearing.

The effect of muscle relaxant on the paraspinal muscle blood flow: a randomized controlled trial in patients with chronic low back pain

STUDY DESIGN

A randomized controlled trial.

OBJECTIVE

To investigate the effect of muscle relaxant for muscle blood flow at the trunk muscle in patients with chronic low back pain (LBP).

SUMMARY OF BACKGROUND DATA

Paraspinal muscle function is widely believed to play a role and considered to be of etiologic significance in LBP, and intramuscular pressure increases and blood flow decreases in the flexion position. Decrease in oxygenated hemoglobin at the trunk muscle is seen in patients with LBP.

METHODS

A total of 74 male patients with LBP lasting more than 6 months were randomized to 3 treatment groups: (1) physical therapy only (control) (n = 25), (2) administration of eperisone hydrochloride (EMPP) for 4 weeks (n = 24), and (3) McKenzie therapy (n = 25). The primary outcome variables, observed at 2 and 4 weeks, are the Japanese Orthopedic Association LBP score, visual analogue scale (VAS), Faces Pain Scale-Revised, and SF-36. Intramuscular oxygenation was evaluated using near-infrared spectroscopy during lumbar extension and flexion, and oxygenated hemoglobin and deoxygenated hemoglobin were compared.

RESULTS

VAS was significantly lower at 4 weeks in the McKenzie group than in the control group. There were no significant changes at 2 weeks in all parameters, however, the relative change of oxygenated hemoglobin during lumbar extension at 4 weeks was significantly higher in the EMPP group when compared with the other 2 groups. The relative change of deoxygenated hemoglobin during lumbar flexion showed a significant difference at 4 weeks in the EMPP group when compared with the control group.

CONCLUSION

Administration of EMPP for 4 weeks improved the LBP in VAS, though not as effective as McKenzie therapy. Our data demonstrated the effects of eperisone hydrochloride on paraspinal muscle hemodynamics improving intramuscular oxygenation during lumbar extension and flexion in patients with chronic LBP.

Treatment of a Case of Subacute Lumbar Compartment Syndrome Using the Graston Technique

OBJECTIVE

To discuss subacute lumbar compartment syndrome and its treatment using a soft tissue mobilization technique.

CLINICAL FEATURES

A patient presented with low back pain related to exercise combined with prolonged flexion posture. The symptoms were relieved with rest and lumbar extension. The patient had restrictive lumbar fascia in flexion and rotation and no neurological deficits.

INTERVENTION AND OUTCOME

The restrictive lumbar posterior fascial layers and adjoining restrictive fascia (thoracic, gluteal, hamstring) were treated with a form of instrument-assisted soft tissue mobilization called the Graston technique. Restoration of fascial extensibility and resolution of the complaint occurred after 6 treatment visits.

CONCLUSIONS

The posterior spinal fascial compartments may be responsible for intermittent lower back pain. Functional clinical tests can be employed to determine whether the involved fascia is abnormally restrictive. Treatment directed at the restrictive fascia using this soft tissue technique may result in improved fascial functional testing and reduction of symptoms.

Intramuscular pressure, tissue oxygenation and EMG fatigue measured during isometric fatigue-inducing contraction of the multifidus muscle

Simultaneous measurement of intramuscular pressure (IMP), tissue oxygen partial pressure (pO(2)) and EMG fatigue parameters in the multifidus muscle during a fatigue-inducing sustained muscular contraction. The study investigated the following hypotheses: (1) Increases in IMP result in tissue hypoxia; (2) Tissue hypoxia is responsible for loss of function in the musculature. The nutrient supply to muscle during muscle contraction is still not fully understood. It is assumed that muscle contraction causes increased tissue pressure resulting in compromised perfusion and tissue hypoxia. This tissue hypoxia, in turn, leads to muscle fatigue and therefore to loss of function. To the authors' knowledge, no study has addressed IMP, pO(2) and EMG fatigue parameters in the same muscle to gain a deeper sight into muscle perfusion during contraction. As back muscles need to have a constant muscular tension to maintain trunk stability during stance and locomotion, muscle fatigue due to prolonged contraction-induced hypoxia could be an explanation for low back pain. Sixteen healthy subjects performed an isometric muscular contraction exercise at 60% of maximum force until the point of localized muscular fatigue. During this exercise, the individual changes of IMP, pO(2) and the median frequency (MF) of the surface EMG signal of the multifidus muscle were recorded simultaneously. In 12 subjects with a documented increase in intramuscular pressure, only five showed a decrease in tissue oxygen partial pressure, while this parameter remained unchanged in six other subjects and even increased in one. A fall in tissue pO(2) was associated with a drop in MF in only five subjects, while there was no correlation between these parameters in the other 11 subjects. To summarize, an increase in IMP correlated with a decrease in pO(2) and a drop in MF in only five out of 16 subjects. High intramuscular pressure values are not always associated with a hypoxia in muscle tissue. Tissue hypoxia is not automatically associated with a median frequency shift in the EMG signal's power spectrum.

Simultaneous measurement of intramuscular pressure and surface electromyography of the multifidus muscle

The anatomic proof of a spinal compartment and the clinical symptoms of compartment syndrome in patients with chronic back pain are inconsistent with the rarely met measuring criteria of intramuscular pressure (IMP). Previous studies assume a dependence of the IMP on spinal alignment (degree of lumbar spine flexion) and the degree of muscle activation. The significance of these disturbance variables in the interpretation of IMP could explain the above discrepancy. This study therefore investigates the influence of both a 30% increase in trunk flexion and alterations in muscle contraction from 100% to 60%. Sixteen healthy subjects participated in the study. The IMP and mean rectified amplitude of the multifidus surface EMG signal were determined at rest and 0 degrees and approximately 30 degrees of lumbar spine flexion, and they were compared. Subsequently, both parameters were measured during both 100% and 60% maximal voluntary contraction (MVC) of the muscle and then correlated. During rest and 0 degrees flexion, the median IMP was 9.3 mmHg (range 0.0-22.5) while the median mean rectified amplitude (MRA) of the EMG signal was 1.98 microV (range 1.32-7.38). In 30 degrees flexion, the median IMP went up to 24.3 mmHg (range 1.4-97.3) with hardly any increase in the median MRA of 2.32 microV (range 1.20-9.72). Under 60% MVC, the median IMP rose to 186.6 mmHg (range 15.4-375.4) and the median MRA to 21.02 microV (range 4.63-43.63). During 100% MVC, the median MRA increased to 34.38 microV (range 12.99-102.54) while the median IMP rose to 273.4 mmHg (range 90.4-395.1). Spearman's rank correlation coefficient for the IMP and MRA quotients of the 100/60% MVC values was r= -0.21. To sum up, it can be said that IMP was subject to great interindividual variation in all the experiments. This parameter is highly dependent on spinal alignment and muscular activity. Further studies are needed so that the IMP can be interpreted properly when diagnosing a chronic compartment of the erector spinae muscles.

Acquired degenerative changes of the intervertebral segments at and suprajacent to the lumbosacral junction

A review of the imaging features of normal and degenerative anatomy of the spine on medical imaging studies shows features that have been largely overlooked or poorly understood by the imaging community in recent years. The imaging methods reviewed included computed tomography (CT) with multiplanar reconstructions and magnetic resonance imaging (MRI). A routine part of the MRI examination included fat-suppressed T2 weighted fast-spin- or turbo-spin-echo acquisitions. As compared to the normal features in asymptomatic volunteers, alterations in the observed CT/MRI morphology and MR signal characteristics were sought in symptomatic individuals. Findings in symptomatic subjects which departed from the normal anatomic features of the posterior spinal elements in asymptomatic volunteers included: rupture of the interspinous ligament(s), neoarthrosis of the interspinous space with perispinous cyst formation, posterior spinal facet (zygapophyseal joint) arthrosis, related central spinal canal, lateral recess (subarticular zone) and neural foramen stenosis, posterior element alterations associated with various forms of spondylolisthesis, and perispinal muscle rupture/degeneration. These findings indicate that the posterior elements are major locations of degenerative spinal and perispinal disease that may accompany or even precede degenerative disc disease. Although not as yet proven as a reliable source of patient signs and symptoms in all individuals, because these observations may be seen in patients with radicular, referred and/or local low back pain, they should be considered in the evaluation of the symptomatic patient presenting with a clinical lumbosacral syndrome. Imaging recommendations, in addition to the usual close scrutiny of these posterior spinal elements and perispinal soft tissues on CT and MRI, include the acquisition of high-resolution multiplanar CT reconstructions, and fat-suppressed T2 weighted fast-spin- or turbo-spin-echo sequence MRI in at least one plane in every examination of the lumbar spine.

Oxygen dynamics at paraspinal muscles during exertion using near-infrared spectroscopy in patients with degenerative lumbar scoliosis

Oxygen dynamics were measured in both sides of the paraspinal muscles of patients with degenerative lumbar scoliosis. The objective was to investigate the extent of stress by measuring the changes in oxygenation and blood flow volume using near-infrared spectroscopy. There were 44 patients with degenerative lumbar scoliosis (7 men, 37 women) and 11 controls with no scoliosis (2 men, 9 women). The measured recovery time for deoxyhemoglobin indicated the recovery from energy deficit after exercise. The average recovery time of the 11 control subjects was 2.4 +/- 0.7 s on the right and 2.4 +/- 0.8 s on the left. Among the 44 patients the average recovery time was 3.8 +/- 1.8 s on the convex side and 2.1 +/- 1.1 s on the concave side. There was a significant difference between the two groups. The recovery time on the concave side in patients was faster than that on the convex side. The results of the current study support the theory that stretching the muscles at the convex side results in chronic increases in the intramuscular compartment and reduced muscular blood flow.

Lumbar paraspinal rhabdomyolysis and compartment syndrome after abdominal aortic aneurysm repair

Lumbar paraspinal compartment syndrome is an extremely uncommon condition that is known to occur after strainful exercise or trauma. We report on the original case of a 55-year-old man in whom lumbar paraspinal rhabdomyolysis and compartment syndrome developed after open abdominal aortic aneurysm repair, documented with technetium Tc(99m) bone scan and computed tomographic imaging, and in whom successful complete recovery was achieved with conservative management. Clinical features, pathophysiology, and diagnostic and therapeutic strategies of this unusual adverse event are discussed.

Acquired degenerative changes of the intervertebral segments at and suprajacent to the lumbosacral junction. A radioanatomic analysis of the nondiskal structures of the spinal column and perispinal soft tissues

In earlier evolutionary times, mammals were primarily quadrupeds. However, other bipeds have also been represented during the course of the Earth's several billion year history. In many cases, either the bipedal stance yielded a large tail and hypoplastic upper extremities (e.g., Tyrannosaurus rex and the kangaroo), or it culminated in hypoplasia of the tail and further development and specialization of the upper extremities (e.g., nonhuman primates and human beings). In the human species this relatively recently acquired posture resulted in a more or less pronounced lumbosacral kyphosis. In turn, certain compensatory anatomic features have since occurred. These include the normal characteristic posteriorly directed wedge-shape of the L5 vertebral body and the L5-S1 intervertebral disk; the L4 vertebral body and the L4-L5 disk may be similarly visibly affected. These compensatory mechanisms, however, have proved to be functionally inadequate over the long term of the human life span. Upright posture also leads to increased weight bearing in humans that progressively causes excess stresses at and suprajacent to the lumbosacral junction. These combined factors result in accelerated aging and degenerative changes and a predisposition to frank biomechanical failure of the subcomponents of the spinal column in these spinal segments. One other specific problem that occurs at the lumbosacral junction that predisposes toward premature degeneration is the singular relationship that exists between a normally mobile segment of spine (i.e., the lumbar spine) and a normally immobile one (i.e., the sacrum). It is well known that mobile spinal segments adjacent to congenitally or acquired fused segments have a predilection toward accelerated degenerative changes. The only segment of the spine in which this is invariably normally true is at the lumbosacral junction (i.e., the unfused lumbar spine adjoining the fused sacrum). Nevertheless, biomechanical failures of the human spine are not lethal traits; in most cases today, mankind reaches sexual maturity before spinal biomechanical failure precludes sexual reproduction. For this gene-preserving reason, degenerative spinal disorders will likely be a part of modern societies for the foreseeable eternity of the race. The detailed alterations accruing from the interrelated consequences of and phenomena contributing to acquired degenerative changes of the lumbosacral intervertebral segments as detailed in this discussion highlight the extraordinary problems that are associated with degenerative disease in this region of the spine. Further clinicoradiologic research in this area will progressively determine the clinical applications and clinical efficacy of the various traditional and newer methods of therapy in patients presenting with symptomatic acquired collapse of the intervertebral disks at and suprajacent to the lumbosacral junction and the interrelated degenerative alterations of the nondiskal structures of the spine.

Lumbar paraspinal myonecrosis after abdominal vascular surgery: a case report

STUDY DESIGN

Case report.

OBJECTIVES

Lumbar paraspinal myonecrosis after abdominal vascular surgery.

SUMMARY OF BACKGROUND DATA

Lumbar paraspinal myonecrosis does not appear to have been reported previously.

METHODS

A patient who had severe back pain after abdominal vascular surgery was observed with computed tomographic scans and histologic examination of a specimen obtained in open biopsy.

RESULTS

Computed tomographic scans of the lumbar region demonstrated muscle swelling of the unilateral paraspinal compartment. Histologic examinations of affected muscle revealed fresh ischemic necrosis. A compartmental syndrome was considered from the patient's clinical presentation and radiographic and histologic features. An accompanying secondary infection led to an extensive abscess in the paraspinal compartment. The patient resumed active daily life after aggressive débridements of infected and necrotic muscles.

CONCLUSIONS

A compartmental syndrome in the paraspinal muscle should be kept in mind as a potential cause of acute back pain especially after abdominal vascular surgery.

Attachments of the posterior layer of lumbar fascia

STUDY DESIGN

Superficial and deep laminae of the posterior layer of lumbar fascia were dissected. The lumbar portion was measured for evidence of segmental thickenings. Superior attachments were dissected, documented, and photographed.

OBJECTIVES

To verify the existence of posterior accessory ligaments and establish the superior attachments and fiber angles of the posterior layer of lumbar fascia.

SUMMARY OF BACKGROUND DATA

There have been two small dissection studies on the posterior layer. Their findings are conflicting in several areas of clinical significance. Thickenings in the lumbar region were described in one study, but have not been verified. The superior attachments of the posterior layer have not been formally documented.

METHODS

Study 1: In 21 embalmed cadavers, the lumbar region of the posterior layer was dissected. The lumbar spinous processes and adjacent fascia were marked. The fascia was removed and examined, and its thickness measured with a manual micrometer. Results were statistically analyzed. Study 2: Superior attachments of the posterior layer in 20 cadavers were dissected and photographed. Capacity to transmit tension was estimated and documented photographically, and fiber angles measured in situ.

RESULTS

Study 1: There was no evidence of macroscopic segmental thickening in the posterior layer. Study 2: The superficial lamina was continuous superiorly with the rhomboids, and the deep lamina with the tendons of splenius cervices and capitis. These previously undocumented attachments were of variable thickness and fibrosity, and capable of transmitting tension.

CONCLUSIONS

Both superficial and deep laminae of the posterior layer are more extensive superiorly than previously thought. This may have implications for certain tests used in assessment and management of low back pain such as the slump and "nonorganic" tests. The thickness of the superior attachments is variable. Their capacity for load bearing is yet to be quantified.

Intramuscular pressure in the erector spinae and intra-abdominal pressure related to posture and load

STUDY DESIGN

Intramuscular pressures in both Erectors Spinae and intra-abdominal pressures were measured during different holding tasks.

OBJECTIVES

To investigate the potential for using intramuscular pressure measurements in both Erectors Spinae to better quantitate the role of muscles during different lifting tasks in vivo.

SUMMARY OF BACKGROUND DATA

Intramuscular pressure and intra-abdominal pressure were measured previously under isometric and dynamic conditions. However, no previous study systematically has addressed the relation between intramuscular and intra-abdominal pressures and different loads, tasks, and postures.

METHODS

Intramuscular and intra-abdominal were measured simultaneously with microtip pressure transducers in 10 healthy volunteers performing 24 different static holding tasks. Tasks included different weights (10 kg and 20 kg), postures (squat or back lift), and positions of the weight.

RESULTS

Intramuscular pressures were dependent on posture. Kyphotic back posture produced intramuscular pressures of 120-130 mm Hg, compared with the 10-25 mm Hg produced when volunteers were in the erect position (P < 0.001). Holding a 10-kg weight at the thighs close to the body produced significantly (P < 0.001) lower intramuscular pressures (25-32 mm Hg) than that produced by holding it 25 cm in front of the body (47-56 mm Hg). In all tasks, intramuscular pressures were significantly higher with the 20-kg weight than with the 10-kg weight (P < 0.001). Highest values (> 300 mm Hg) were measured when the 20-kg weight was held in the kyphotic posture above the floor and 25 cm away from the body.

CONCLUSIONS

Intramuscular pressure measurements in the erector spinae seem to be a valuable tool for quantitating the role of back muscles during different lifting tasks.