A randomised controlled trial of the efficacy of ultrasound-guided transversus abdominis plane (TAP) block in laparoscopic colorectal surgery

BACKGROUND

Optimal analgesia following laparoscopic colorectal resection is yet to be determined; however, recent studies have questioned the role of postoperative epidural anaesthesia, suggesting other analgesic modalities may be preferable. The aim of this randomised controlled trial was to assess the effect of transversus abdominis plane (TAP) blocks on opioid requirements in patients undergoing laparoscopic colorectal resection.

METHODS

After appropriate trial registration ( www.clinicaltrials.gov NCT 00830089) and local medical ethics review board approval (REC 09/H0407/10), all adult patients who were to undergo laparoscopic colorectal surgery at a single centre were randomised into the intervention group receiving bilateral TAP blocks or the control group (no TAP block). The blocks were administered prior to surgery after the induction of a standardised anaesthetic by an anaesthetist otherwise uninvolved with the case. The patient, theatre anaesthetist, surgeon, and ward staff were blinded to treatment allocation. All patients received postoperative analgesia of paracetamol and morphine as a patient-controlled analgesia (PCA). Cumulative opioid consumption and pain scores were recorded at 2, 4, 6, and 24 h postoperatively and compared between the groups as were clinical outcomes and length of stay.

RESULTS

The intervention (TAP block) group (n = 33) and the control group (n = 35) were comparable with respect to characteristics, specimen pathology, and type of procedure. The TAP block group's median cumulative morphine usage (40 mg [IQR = 25-63]) was significantly less than that of the control group (60 mg [IQR = 39-81]). Pain scores and median length of stay (LOS) were similar between the two groups.

CONCLUSION

Preoperative TAP blocks in patients undergoing laparoscopic colorectal resection reduced opioid use in the first postoperative day in this study.

[Diagnostic ideas and programs of lumbar intervetebral disc herniation]

Lumbar intervertebral disc herniation (LIDH) is one of the most common causes of lumbocrural pain with its uncertain causes, varied clinical manifestations and featuring on each individual case. Effective individualized therapy scheme depends on the correct and timely diagnosis of this disease. Many evidence indicated that the nervous symptoms and signs have higher specificity and sensitivity, has great significance to the diagnosis of LIDH but usually has polytropy among different patients or different period and conditioning of the same patient to some degree. This article systematically reviewed and analyzed the diagnostic value of specific symptoms and signs, selected physical and photographical examination methods of LIDH, and proposed that LIDH can be accurately and timely evaluated by using these diagnostic factors and ways comprehensively and systematically, this will be the helpful ideas and program to the diagnosis of this disease.

Lumbosacral intrathecal nerve roots: an anatomical study

BACKGROUND

The lumbosacral intrathecal anatomy is complex because of the density of nerve roots in the cauda equina. Space-occupying lesions, including disc herniation, trauma and tumor, within the spinal canal may compromise the nerve roots, causing severe clinical syndromes. The goal of this study is to provide spinal surgeons with a detailed anatomical description of the intrathecal nerve roots and to emphasize their clinical importance.

METHOD

Ten formalin-fixed male cadavers were studied. They were dissected with the aid of a surgical microscope, and measurements were performed.

RESULTS

The number of dorsal and ventral roots ranged from one to three. The average diameter of roots increased from L1 to S1 (0.80 mm for L1 and 4.16 for S1), respectively. Then their diameter decreased from S1 to S5 (4.16 mm for S1, 0.46 mm for S5). The largest diameter was found at S1 and the smallest at S5. The average number of rootlets per nerve root increased from L1 to S1, then decreased (3.25 for L1, 12.6 for S1, and 1.2 for S5), respectively. The greatest rootlet number was seen at S1, and the fewest were observed at S5. The average diameter of the lateral recess gradually decreased from L1 to L4 (9.1 mm for L1; 5.96 mm for L4) and then increased at L5 level (6.06 mm); however, the diameter of the nerve root increased from L1 to L5. The midpoint of distance between the superior and inferior edge of the intradural exit nerve root was 3.47 mm below the inferior edge of the superior articular process at the L1 level, while the origin of the L5 exit root was 5.75 mm above the inferior edge. The root origin gradually ascended from L1 to L5.

CONCLUSIONS

The findings of this study may be valuable for understanding lesions compressing intradural nerve roots and may be useful for intradural spinal procedures.

The use of lumbar sympathetic blockade at L4 for management of malignancy-related bladder spasms

BACKGROUND

Cancer-related bladder spasms may be a rare but severe symptom of bladder or metastatic cancer or its related treatments. Various treatments described in the literature include systemic medications, intravesical or epidural medications, or even sacral neurolectomies.

OBJECTIVE

We present 3 patients who have suffered from bladder spasm either from invasion of the bladder wall by tumor (2 patients) or from intravesical chemotherapeutic treatment.

DESIGN

Case Report.

SETTING

Cancer pain management hospital.

METHODS

For each patient, we describe the use of lumbar sympathetic block to successfully treat the bladder spasms. Sympathetic blockade was performed at the left anterolateral border of lumbar vertebra L4. We used 10 mL of local anesthetic (0.25% bupivacaine) delivered in 2 mL aliquots, each given after negative aspiration for heme. Each procedure was performed with fluoroscopic guidance (both AP and lateral views) with the use of iodine contrast (Omnipaque-180) to confirm the location of the medication and its resulting spread.

RESULTS

All 3 patients had a reduction in the frequency and intensity of spasms, with 2 out of 3 patients not having a recurrence of the spasms for up to 2 months post procedure and follow up.

LIMITATIONS

Case Report.

CONCLUSION

Lumbar sympathetic blockade could be a useful treatment for recurrent bladder spasm in the oncologic population. Based on these findings, we feel that the branches of the sympathetic nerve set at L4 may be a good target for neurolytic procedures, such as radiofrequency ablation, for long term treatment of bladder spasms. Further research is necessary to determine the efficacy of this technique for the treatment of bladder spasms in the oncologic population.

Characterization of intrathecally administered hemokinin-1-induced nociceptive behaviors in mice

Hemokinin-1 is a novel mammalian tachykinin cloned from mouse bone marrow. At present, pharmacological profile and physiological role of hemokinin-1 are still unclear. In the present study, we found that intrathecal (i.t.) administration of hemokinin-1 (0.00625-1.6 nmol) induced nociceptive responses consisting of scratching, biting and licking, which resemble substance P-induced behavioral responses in mice. The behaviors evoked by low-dose of hemokinin-1 (0.0125 nmol) were dose-dependently inhibited by i.t. co-administration of CP-99,994, a non-peptidic tachykinin NK(1) receptor antagonist, whereas high-dose of hemokinin-1 (0.1 nmol)-induced behaviors were not affected. Moreover, sendide, a peptidic tachykinin NK(1) receptor antagonist, failed to reduce the behavioral responses of both low- and high-dose of hemokinin-1. In contrast, substance P-induced behaviors were completely suppressed by both CP-99,994 and sendide. These results suggest that hemokinin-1 plays an important role in pain transmission at spinal cord. Moreover, the mechanism of hemokinin-1-induced nociceptive behaviors may be dose-dependent, and distinct from substance P-induced nociceptive behaviors.

Functional anatomy of the caudal thoracolumbar and lumbosacral spine in the horse

REASONS FOR PERFORMING STUDY

Research in spinal biomechanics and functional anatomy has advanced back pain research in man. Yet, despite the performance limiting nature of back pain in horses, there are few data for the equine spine.

OBJECTIVES

To describe aspects of functional anatomy of the equine thoracolumbar and lumbosacral (LS) spine and potential effects on performance.

METHODS

The first study investigated variations in LS vertebral formula by post mortem examination of 120 horses. Midline vertebral transection was carried out on 65 Thoroughbred (TB), 24 Standardbred (SB) and 31 other breeds. The second study investigated morphology and biomechanics of the deep stabilising epaxial muscles of 13 horses using MRI (n = 3), anatomical dissection (n = 11) and biomechanical analysis (n = 6). The spinous process angular orientation relative to the vertebral body, was analysed at vertebrae T13, T18, L3, L5, L6 and S1.

RESULTS

LS variations were found in 33.3% of the total group, 40.0% TB and 45.2% others, but 0% SB. Sacralisation of lumbar vertebra (L) 6 with LS motion between L5 and L6 occurred in 32.3% TB and 29.0% others. Five segmental multifidus fascicles were identified originating from spinous processes and vertebral laminae running craniocaudally onto the mammillary processes and lateral border of the sacrum, crossing between 1-5 intervertebral discs. Sacrocaudalis dorsalis (SCD) lateralis muscle was an extension of multifidus from L4, L5 and L6 depending on the vertebral formula whereas SCD medialis mm originated from S3. Both inserted on caudal vertebrae. Based on the location and direction of fibres, the principal action of the deep epaxial muscles was dorsoventral sagittal rotation. This action was dependent on vertebral spinous process/body orientation. We hypothesise that equine multifidus and SCD lateralis muscles act as caudal sagittal rotators of their vertebra of origin, as is the case in man, allowing dynamic stabilisation during dorsoventral motion.

CONCLUSION

Equine multifidus anatomy and function are comparable to that of man. The high prevalence of anatomical variations in the LS spine may affect maximal dorsoventral motion, the stability of the LS joint and, therefore, have consequences for athletic performance. Further studies of these structures are warranted in appropriately selected poorly performing horses.

Effects of capsaicin-induced sensory denervation on bone metabolism in adult rats

Bone metabolism has recently been revealed to be under nerve regulation. In this study, the integrity of the sensory innervation contributing to bone metabolism was examined by capsaicin-induced sensory neuron lesions. Eight-week-old male Wistar strain rats in a modeling phase of skeletal growth were divided into four groups (8 rats per group) and treated with capsaicin at one of three different doses (37.5, 75, 150 mg/kg) or vehicle, subcutaneously. Five weeks later, high-dose (150 mg/kg) capsaicin treatment had reduced trabecular bone volume (BV/TV) due to increased trabecular separation (Tb.Sp) in the proximal tibia and the modification of mechanical properties such as strength, ductility, and toughness toward increasing bone fragility in the trunk of the sixth lumbar vertebrae (L6). Moderate-dose (75 mg/kg) capsaicin treatment had no significant effect on trabecular BV/TV or bone mechanical properties but increased Tb.Sp as seen high-dose capsaicin treatment. Bone histomorphometry showed osteoclast number (Oc.N/BS) and surface (Oc.S/BS) were increased in both the moderate-dose and high-dose capsaicin treatment groups. High-dose capsaicin significantly increased the level of tartrate-resistant acid phosphatase form 5b (TRAP 5b) in plasma, a systemic bone resorption marker, but had no influence on plasma osteocalcin concentration, a bone formation marker, suggesting that capsaicin-induced sensory nerve denervation increased bone resorption but had no influence on bone formation. Low-dose (37.5mg/kg) capsaicin had no influence on bone remodeling. These results suggest that sensory nerve innervation contributes to the maintenance of trabecular bone mass and its mechanical properties by inhibiting bone resorption.

Innervation and nerve injections of the lumbar spine of the horse: a cadaveric study

REASONS FOR PERFORMING STUDY

The distal limb innervation of the horse has been studied extensively to allow use of local anaesthetic techniques to detect the origin of pain in lameness. However, the innervation of the lumbar spine has so far been poorly described and a more precise description may assist clinicians to localise back pain in the horse.

OBJECTIVES

To gain better knowledge of the innervation of the lumbar spine and identify salient anatomical features that might be used for diagnostic and therapeutic ultrasound guided injections.

METHODS

The spines of 8 mature horses were dissected. Branches of the dorsal rami were followed and their anatomical relationship, with articular facets, interspinous structures and muscles, noted. The spines of 3 other horses were sectioned transversely and dissected to identify ultrasonographic landmarks of the nerves. Six other spines were used to assess the accuracy of ultrasound guided injections of the nerves with blue dye.

RESULTS

Gross dissections confirmed the dual segmental innervation of the articular facets. Each lumbar articular facet of 2 lumbar vertebrae was innervated by the medial branch of the dorsal ramus exiting from the intervertebral foramen between those vertebrae, but also by the branch originating of the dorsal ramus cranial to it. The medial branch divided into 2 nerves before exiting the intertransverse space and has salient anatomical landmarks which could be identified ultrasonographically. The ultrasound guided injection technique appeared to be of an accuracy that would be clinically useful.

CONCLUSION

The results identified that the salient anatomical features of the medial branch of the dorsal ramus, as described in the present study, can be used as landmarks for reliable ultrasound-guided injection.

POTENTIAL RELEVANCE

This study has a clear clinical relevance for development of diagnostic and therapeutic injection techniques of the lumbar spine in the horse.

Accuracy of diagnostic lumbar facet joint nerve blocks: a 2-year follow-up of 152 patients diagnosed with controlled diagnostic blocks

BACKGROUND

Lumbar facet joint pain is diagnosed by controlled diagnostic blocks. The accuracy of controlled diagnostic blocks has been demonstrated in multiple studies and confirmed in systematic reviews. Controlled diagnostic studies have shown an overall prevalence of lumbar facet joint pain in 31% of the patients with chronic low back pain without disc displacement or radiculitis, with an overall false-positive rate of 30% using a single diagnostic block.

STUDY DESIGN

An observational report of outcomes assessment.

SETTING

An interventional pain management practice setting in the United States.

OBJECTIVE

To determine the accuracy of controlled diagnostic blocks in managing lumbar facet joint pain at the end of 2 years.

METHODS

This study included 152 patients diagnosed with lumbar facet joint pain using controlled diagnostic blocks. The inclusion criteria was based on a positive response to diagnostic controlled comparative local anesthetic lumbar facet joint blocks. The treatment included therapeutic lumbar facet joint nerve blocks.

OUTCOME MEASURES

The sustained diagnosis of lumbar facet joint pain at the end of one year and 2 years based on pain relief and functional status improvement.

RESULTS

At the end of one year 93% of the patients and at the end of 2 years 89.5% of the patients were considered to have lumbar facet joint pain.

LIMITATIONS

The study is limited by its observational nature.

CONCLUSION

Controlled diagnostic lumbar facet joint nerve blocks are valid utilizing the criteria of 80% pain relief and the ability to perform previously painful movements, with sustained diagnosis of lumbar facet joint pain in at least 89.5% of the patients at the end of a 2-year follow-up period.

Presence of NGF and its receptor TrkA in degenerative lumbar facet joint specimens

In a preliminary study, the recurrent presence of nervous terminations was demonstrated with optical microscopy in several slides of degenerative lumbar facet joints and surrounding soft tissues. The purpose of this study was to prove the presence of NGF (nerve growth factor) and its receptor TrkA (tyrosine kinase receptor) with immunofluorescence. The peri/articular tissues were harvested from the lumbar facet joints of ten patients surgically treated for degenerative diseases. There were seven females (one bilateral) and two males whose mean age at surgery was 72 years (range, 67-80 years). The affected levels were L3-L4 in two cases and L4-L5 in seven cases (one bilateral). All specimens were fixed in formalin, dehydrated and enclosed in paraffin. From each specimen, four slides were obtained. Two slides were employed for the search of NGF: one was treated with specific antibodies and marked with FITC (fluorescein isothiocyanate conjugated), and the second slide was for control purposes. It was exposed to FITC, but without prior exposure to the specific antibody. The same procedure was repeated to obtain on two more slides, to repeat the search for Trka with specific antibodies. All the slides were finally studied on a fluoromicroscope. The analysis of these specimens revealed the presence of the neurotrophin (NGF) and its own receptor (TrkA) in all cases: the immunohistochemical reaction between the specimens and the specific antibodies marked with FITC was seen under fluoromicroscopy, but in none of the control cases treated with FITC only. NGF is released by mastocytes, fibroblasts and other cell types involved in the inflammatory processes. The level of peripheral NGF is increased in inflammatory processes, while the administration of exogenous NGF has a hyperalgesic effect on rats and produces muscular pain in humans. Furthermore, NGF produces hypersensitization to heat stimulation in humans and mammals in general. There is considerable evidence showing that the system constituted by the NGF and its high-affinity receptor TrkA plays a fundamental role in the molecular processes underlying the main forms of "persistent" pain. This indicates a possible therapeutic area for the antibodies that could block the NGF/TrkA system, in order to modulate the frequency and the duration of the action potential of nociceptive neurons during chronic inflammation. This study demonstrated the presence of NGF and TrkA in specimens collected from degenerative facet joints, suggesting that specific molecules could be used in order to modulate chronic pain in patients with degenerative lumbar spine.

Systematic review of lumbar discography as a diagnostic test for chronic low back pain

BACKGROUND

The intervertebral disc has been implicated as an etiology of chronic lumbar spine pain based on clinical, basic science, and epidemiological research. However, there is lack of consensus regarding the diagnosis and treatment of intervertebral disc disorders. Based on controlled evaluations, the lumbar intervertebral discs have been shown to be sources of chronic back pain without disc herniation in 26% to 39%. Lumbar provocation discography, which includes disc stimulation and morphological evaluation, is often used to distinguish a painful disc from other potential sources of pain. Despite the extensive literature, controversy continues about provocation lumbar discography.

STUDY DESIGN

A systematic review of the lumbar provocation discography literature.

OBJECTIVES

To systematically assess the diagnostic accuracy of lumbar discography.

METHODS

A systematic review of the literature was performed to assess the diagnostic accuracy of lumbar discography with respect to chronic low back pain. Study inclusion/exclusion criteria were based on International Association for the Study of Pain (IASP) standards with pain provocation and determination of controlled discs. Selected studies were then subjected to a rating instrument for diagnostic accuracy studies. Specific data were then culled from these studies and tabulated. Quality of evidence was assessed using modified Agency for Healthcare Research and Quality (AHRQ) diagnostic accuracy evaluation. Studies meeting methodologic quality criteria scores of 50 or higher were included in the assessment of the level of evidence. Qualitative analysis was conducted using 5 levels of evidence, ranging from Level I to III, with 3 subcategories in Level II. The rating scheme was modified to evaluate the diagnostic accuracy.

RESULTS

Based on a modified U.S. Preventive Services Task Force (USPSTF) level of evidence criteria, this systematic review indicates the strength of evidence as Level II-2 for the diagnostic accuracy of lumbar provocation discography utilizing IASP criteria.

LIMITATIONS

Limitations include a paucity of literature, poor methodologic quality, and very few studies performed utilizing IASP criteria.

CONCLUSION

Based on the current systematic review, lumbar provocation discography performed according to the IASP criteria with control disc (s) with minimum pain intensity of 7 of 10, or at least 70% reproduction of worst pain (i.e. worst spontaneous pain of 7 = 7 x 70% = 5) may be a useful tool for evaluating chronic lumbar discogenic pain. Discography is an important imaging and pain evaluation tool in identifying a subset of patients with chronic low back pain secondary to intervertebral disc disorders.

Ultrasound guided, painful electrical stimulation of lumbar facet joint structures: an experimental model of acute low back pain

Quantitative sensory testing has indicated generalized muscle hyperalgesia in patients with chronic low back pain. The temporal development of such hyperalgesia is not well understood. The aim of the present study was to demonstrate whether generalized muscle hyperalgesia can develop within minutes of acute low back pain using a new experimental model of lumbar facet joint pain. Thirteen healthy volunteers were included and baseline pressure pain thresholds were assessed at eight separate sites, outside the area of evoked low back and referred pain. Using ultrasonography, two electrode needles were placed either side of a lumbar facet joint (right L3-4) and used to induce experimental low back pain for 10 min with continuous stimulation. Thresholds, stimulus-response relationships, distribution and quality of the electrically induced pain were recorded. Electrical facet joint stimulation induced low back pain and pain referral into the anterior leg, ipsilaterally, proximal to the knee, similar to what is observed clinically. Pressure pain thresholds did not change significantly before, during and after facet joint stimulation. In conclusion, we describe a novel model of acute experimental low back pain and demonstrate that generalized hyperalgesia did not develop within minutes of acute low back pain.

Radiofrequency cannula with active tip radio-opaque marker: image analysis for facet, gray ramus, and dorsal root ganglion techniques

BACKGROUND

Radiofrequency neurolysis is a common technique used in the treatment of chronic pain, particularly facet (zygapophyseal joint) arthralgia. A needle-like cannula is insulated except for the exposed active tip, which is positioned as parallel and adjacent as possible to the targeted nerve branch. Via an inserted probe connected to a radiofrequency generator, energy flowing from the tip of the cannula creates a heat lesion in the 80 - 85 degree Celsius range mostly about the length of the exposed active tip and in proportion to the diameter of the probe. The common active tip lengths used for neurolysis are 5mm or 10mm. The cannulae are FDA approved. The manufacturer advises physicians not to bend or otherwise modify a cannula prior to use. The cannulae are available straight or bent, sharp and blunt. The technique is guided under C-arm fluoroscopy. X-rays passing through the patient demonstrate in 2 dimensions the projected relative radio-opaque bony landmarks and the metallic cannula. Most currently available cannulae are uniform in their radio-opacity from tip to hub. The physician must make an educated guess as to the portion of the cannula that will be making the lesion in relationship to the bony landmark.

OBJECTIVE

A new radiofrequency cannula with a radio-opaque marker (ROC) delineates the proximal end of the active tip. The cannula was used in a phantom model. Images were reproduced with explanation of the potential advantage of the new device.

RESULT

The marker on the new cannula was visible and did help delineate the active tip as well as its orientation. It was also helpful in making sequential lesions at the same nerve using a "tip to tail" repositioning technique.

CONCLUSION

The ROC did represent an improvement over standard cannulae to optimize visualization of cannula and thus lesion placement using a phantom model. The applications described were only for conventional or "hot" RF.

Electric efficiency of the erector spinae in high performance amateur tennis players

AIM

The aim of the paper was to evaluate neuromuscular activity patterns of the lumbar erector spinae during isometric voluntary maximum trunk extension and how this could be influenced through a back exercise home program in high performance amateur tennis players.

METHODS

Experimental longitudinal study of the lower back in a clinical setting. Seventy high performance amateur tennis players underwent isometric trunk extension tests in a specially built apparatus with simultaneous surface electromyography (EMG) recording from right and left lumbar erector spinae. Imbalance quotients were calculated using Electric Efficiency measures. Isometric and electromyographic changes were reviewed after a 7-week daily home program of back exercise.

RESULTS

Neuromuscular imbalance of the lumbar erector spinae associated with reduced Electric Efficiency, closely related to handedness was observed amongst tennis athletes at the start of the study. After a 7-week back exercise home program, lumbar neuromuscular imbalances were evened out and the Electric Efficiency of the erector spinae improved significantly at lumbar level L2 and L4. No significant difference was measured in maximal isometric trunk extension strength.

CONCLUSION

The asymmetric trunk loading caused by tennis specific biomechanics with trunk hyperextension motions and trunk rotation seems to induce imbalanced muscle activity patterns of the lumbar erector spinae. A home program of back exercises for tennis players can help to compensate for these imbalances, improves Electric Efficiency patterns of the erector spinae and should therefore be integrated in the daily training routine of high performance tennis players.

The nerve supply of the lumbar intervertebral disc

The anatomical studies, basic to our understanding of lumbar spine innervation through the sinu-vertebral nerves, are reviewed. Research in the 1980s suggested that pain sensation was conducted in part via the sympathetic system. These sensory pathways have now been clarified using sophisticated experimental and histochemical techniques confirming a dual pattern. One route enters the adjacent dorsal root segmentally, whereas the other supply is non-segmental ascending through the paravertebral sympathetic chain with re-entry through the thoracolumbar white rami communicantes. Sensory nerve endings in the degenerative lumbar disc penetrate deep into the disrupted nucleus pulposus, insensitive in the normal lumbar spine. Complex as well as free nerve endings would appear to contribute to pain transmission. The nature and mechanism of discogenic pain is still speculative but there is growing evidence to support a 'visceral pain' hypothesis, unique in the muscloskeletal system. This mechanism is open to 'peripheral sensitisation' and possibly 'central sensitisation' as a potential cause of chronic back pain.

Preliminary morphological evidence that vertebral hypomobility induces synaptic plasticity in the spinal cord

OBJECTIVE

A widely accepted theoretical model suggests that vertebral hypomobility can cause pain and abnormal spinal mechanics because of changes in sensory input from spinal and paraspinal tissues. The purpose of this pilot study was 3-fold: (1) to make a preliminary determination if chronic vertebral hypomobility at L4 through L6 in the rat would affect synaptic density and/or morphology in the superficial dorsal horn of the L2 spinal cord level, (2) to identify relevant outcome variables for future studies, and (3) to obtain preliminary data that would permit estimating an appropriate sample size for future studies.

METHODS

Using an established rat model, we fixed 3 contiguous lumbar segments (L4-L6) for 8 weeks with a specially engineered vertebral fixation device. Electron micrographs were obtained from 2 animals from the experimental (fixed) group and each of 3 control groups (no surgery, surgery but no devices implanted, and devices implanted but not fixed). Synapses were randomly selected using a stereological approach and were analyzed for symmetry, curvature, type of postsynaptic profile, and perforations. The synaptic density was also estimated.

RESULTS

There was increased synaptic density and percentage of positively curved synapses in the dorsal horn of experimental animals as compared with controls. Experimental animals had a lower percentage of axospinous synapses, with a concomitant increase in the percentage of synapses on dendritic shafts.

CONCLUSIONS

These preliminary data suggest for the first time that chronic vertebral hypomobility at L4 through L6 in the rat affects synaptic density and morphology in the superficial dorsal horn of the L2 spinal cord level. More definitive studies are warranted, and the biologic significance of these finding should be investigated.

Alternative denervation using laser irradiation in lumbar facet syndrome

BACKGROUND AND OBJECTIVE

Facet syndrome is persistent low back pain that might be treated with some surgical interventions. The target of surgical techniques is the transverse process bases where the medial nerve branches innervated the facet. However, highly variable success rates have been demonstrated in different series.

STUDY DESIGN/MATERIALS AND METHODS

We carried out laser denervation to the dorsal surface of the facet capsule, where it is richly innervated with medial nerve branches.

RESULTS

One year after laser denervation, 17 patients (81%) experienced complete or greater than 70% pain reduction in all 21 patients. Among the six patients who had previously undergone spinal surgery, two (33.3%) experienced successful pain relief. Overall, in four patients (19%), the response to laser denervation at 1-year follow-ups was not successful.

CONCLUSION

The dorsal surface of the facet capsule might be a more preferable target for facet denervation.

Sensory innervation of lumbar vertebral bodies in rats

STUDY DESIGN

Using a retrograde neurotracing method with Fluoro-Gold (FG), the level at which dorsal root ganglions (DRGs) innervate the L2 and L5 vertebral bodies and the innervation pathways were investigated in rats.

OBJECTIVE

To clarify the levels at which DRGs innervate the lumbar vertebral bodies and to determine the pathways from the L2 and L5 vertebral bodies to DRGs.

SUMMARY OF BACKGROUND DATA

Elderly patients with osteoporosis sometimes experience lumbar vertebral fracture and may also feel diffuse nonlocalized pain in the back, lateral portion of the trunk, and area surrounding the iliac crest. However, the pattern of sensory innervation of vertebral bodies remains unclear.

METHODS

Forty female Sprague-Dawley rats were used. FG crystals were applied to the L2 (L2 vertebra group) or L5 (L5 vertebra group) vertebral bodies via an anterior approach, and numbers of labeled neurons in DRGs from T10 to L6 were counted. To determine sensory pathways, bilateral sympathectomy was performed.

RESULTS

In nonsympathectomy animals, FG-labeled neurons were present in DRGs from T11 through L3 in the L2 vertebra group and from T13 through L6 in the L5 vertebra group. The number of labeled neurons following sympathectomy was not significantly different in L1, L2, and L3 DRGs in the L2 vertebra group or in L3, L4, L5, and L6 DRGs in the L5 vertebra group from those in nonsympathectomy animals. In contrast, fewer labeled DRG neurons were present in sympathectomy animals at T11, T12, and T13 in the L2 vertebra group, and at T13, L1, and L2 in the L5 vertebra group than in nonsympathectomy animals (P < 0.01).

CONCLUSION

Sensory nerve fibers in the L2 and L5 vertebral bodies are derived from the T11-L3 and T13-L6 DRGs, respectively. Some sensory nerves from the L2 and L5 vertebral bodies enter the paravertebral sympathetic trunks and reach the DRGs at multisegmental levels. The present findings regarding multisegmental innervation to vertebral bodies may explain the diffuse pain that originates within osteoporotic vertebral fractures in elderly patients.

Thoracic and lumbar paravertebral blocks for outpatient lithotripsy

Paravertebral nerve block has been used for a variety of surgical procedures to provide unilateral anesthesia and postoperative analgesia. We report the successful application of this regional anesthesia modality for outpatient lithotripsy. Preoperatively, thoracic and lumbar paravertebral nerve blocks with 0.5% ropivacaine were placed with ultrasound and nerve stimulator guidance for two patients with ureteral calculi. One patient scheduled for cystoscopy and ureteroscopy with laser lithotripsy received general anesthesia intraoperatively. The second patient underwent extracorporeal shock wave lithotripsy with propofol intravenous sedation. Postoperatively, both patients reported pain scores of zero (Visual Analog Scale) for 24 hours and required no opioid rescue analgesia.

Characteristics of Sensory Dorsal Root Ganglia Neurons Innervating the Lumbar Vertebral Body in Rats

Characteristics of sensory dorsal root ganglia (DRG) neurons innervating the L5 vertebral body were investigated in rats by using a retrograde neurotransport method, lectin affinity- and immuno-histochemistry to further elucidate the causes of diffuse pain suffered by some elderly patients in their back, lateral trunk, and iliac crest, after lumbar osteoporotic vertebral fracture. We used calcitonin gene-related peptide (CGRP) as a marker of small peptide-containing neurons and the glycoprotein binding the isolectin from Griffonia simplicifolia (IB4) as a marker of small non-peptide-containing neurons. Neurons innervating the L5 vertebral bodies, retrogradely labeled with fluoro-gold (FG), were distributed throughout DRGs from T13 to L6. The proportion of CGRP-immunoreactive (IR) FG-labeled neurons was 32%. The proportion of IB4-binding FG-labeled neurons was significantly smaller, at 4%. Other neurons that were non-CGRP-IR and non-IB4-binding were mostly large neurons, and they may transmit proprioception from vertebral bodies. Most neurons transmitting pain are CGRP-IR peptide-containing neurons. They may have a more significant role in pain sensation in the vertebral bodies as peptidergic DRG neurons.

PERSPECTIVE

This article shows that vertebral bodies are innervated by CGRP-IR neurons. CGRP-IR neurons may play a role in pain sensation through peptidergic DRG neurons. These findings contribute to an understanding of pain associated with the vertebral body such as tumor, infection, or osteoporotic fracture.

Pathogenesis, diagnosis, and treatment of lumbar zygapophysial (facet) joint pain

Lumbar zygapophysial joint arthropathy is a challenging condition affecting up to 15% of patients with chronic low back pain. The onset of lumbar facet joint pain is usually insidious, with predisposing factors including spondylolisthesis, degenerative disc pathology, and old age. Despite previous reports of a "facet syndrome," the existing literature does not support the use of historic or physical examination findings to diagnose lumbar zygapophysial joint pain. The most accepted method for diagnosing pain arising from the lumbar facet joints is with low-volume intraarticular or medial branch blocks, both of which are associated with high false-positive rates. Standard treatment modalities for lumbar zygapophysial joint pain include intraarticular steroid injections and radiofrequency denervation of the medial branches innervating the joints, but the evidence supporting both of these is conflicting. In this article, the authors provide a comprehensive review of the anatomy, biomechanics, and function of the lumbar zygapophysial joints, along with a systematic analysis of the diagnosis and treatment of facet joint pain.

Up-regulation of p55 TNF alpha-receptor in dorsal root ganglia neurons following lumbar facet joint injury in rats

The rat L5/6 facet joint is multisegmentally innervated from the L1 to L6 dorsal root ganglia (DRG). Tumor necrosis factor (TNF) is a known mediator of inflammation. It has been reported that satellite cells are activated, produce TNF and surround DRG neurons innervating L5/6 facet joints after facet injury. In the current study, changes in TNF receptor (p55) expression in DRG neurons innervating the L5/6 facet joint following facet joint injury were investigated in rats using a retrograde neurotransport method followed by immunohistochemistry. Twenty rats were used for this study. Two crystals of Fluorogold (FG; neurotracer) were applied into the L5/6 facet joint. Seven days after surgery, the dorsal portion of the capsule was cut in the injured group (injured group n = 10). No injury was performed in the non-injured group (n = 10). Fourteen days after the first application of FG, bilateral DRGs from T13 to L6 levels were resected and sectioned. They were subsequently processed for p55 immunohistochemistry. The number of FG labeled neurons and number of FG labeled p55-immunoreactive (IR) neurons were counted. FG labeled DRG neurons innervating the L5/6 facet joint were distributed from ipsilateral L1 to L6 levels. Of FG labeled neurons, the ratio of DRG neurons immunoreactive for p55 in the injured group (50%) was significantly higher than that in the non-injured group (13%). The ratio of p55-IR neurons of FG labeled DRG neurons was significantly higher in total L1 and L2 DRGs than that in total L3, 4, 5 and 6 DRGs in the injured group (L1 and 2 DRG, 67%; L3, 4, 5 and 6 DRG, 37%, percentages of the total number of p55-IR neurons at L1 and L2 level or L3-6 level/the total number of FG-labeled neurons at L1 and L2 level or L3-6 level). These data suggest that up-regulation of p55 in DRG neurons may be involved in the sensory transmission from facet joint injury. Regulation of p55 in DRG neurons innervating the facet joint was different between upper DRG innervated via the paravertebral sympathetic trunks and lower DRG innervated via other direct routes.

[Anatomical study of human lumbar spine innervation]

OBJECTIVE

To explore the detailed innervation of the lumbar spine of humans.

METHODS

Six adult cadavers fixed in a solution containing 10% formalin were investigated under a stereomicroscope. The lumbar spine, together with the abdominal aorta, inferior vena cava and psoas muscle, was extracted. The dissection was focused on various patterns of rami communicantes (RC), including superficial oblique rami (SOR) and deep transverse rami (DTR), and their relationship to the psoas major muscle, the minute nerve supply of the anterior and posterior longitudinal ligaments, vertebral bodies and the intervertebral discs.

RESULTS

Two types of RC were observed: SOR and DTR. SOR ran obliquely between the superficial heads of the psoas major muscle, connecting the sympathetic trunk and T12-L2 spinal nerves non-segmentally. DTR, running along the lumbar arteries and veins, were distributed segmentally, close to the vertebral bodies. On the anterior aspect of the lumbar spine, the anterior longitudinal ligaments received branches from the sympathetic trunk and splanchnic nerves non-segmentally. On the lateral side of the lumbar spine, the vertebral bodies and the intervertebral discs received branches from the DTR and ventral rami segmentally, branches from the sympathetic trunk, and, in the upper lumbar region, SOR non-segmentally. Within the vertebral canal, the posterior aspect of the intervertebral discs and the posterior longitudinal ligaments received the sinu-vertebral nerves originating from DTR.

CONCLUSION

Exist two different types of innervation in the lumbar vertebrae: one originating directly from the spinal nerve segmentally, and one reaching the vertebral body and intervertebral disc via the sympathetic nerves non-segmentally. Therefore, sympathetic nerves are involved in the innervation of the spinal column and intervertebral disc and are likely involved in discogenic low back pain.

Preureteric inferior vena cava with possible rudiment of the proper inferior vena cava

A right single preureteric inferior vena cava (IVC) was found in the cadaver of a 77-year-old Japanese male during a student dissection course at Kumamoto University School of Medicine in 2003. The ureter emerged from the lower end of the hilum of the right kidney at the second lumbar vertebral level. It ran inferomedially to pass behind the IVC, and turned inferolaterally to cross the vein superficially at the level of the third to the fourth lumbar vertebrae. Then, the ureter was situated to the right of the IVC, and descended ordinarily. The second lumbar vein of each side united bilaterally, as did the third lumbar veins. The common stem of the second lumbar veins drained into the left side of the IVC posterolaterally at the level of the second intervertebral disc, and the third common stem opened into the left border of the IVC at the fourth lumbar vertebral level. The ureter hooked around the IVC between the openings of those common stems. There was a small continuation (0.2 mm in diameter) between the left second lumbar and the right third lumbar veins along the vertebral column slightly right of the midline. It passed superficial to the right third lumbar artery, as did the IVC. The right testicular vein opened into the IVC at the level of the lower end of the third lumbar vertebral body. Generally, the level of the opening of the gonadal vein corresponds to the level of the caudal end of the remaining subcardinal vein, but it is lower than usual in this case. Furthermore, the segment from the confluence of the common iliac veins to the common trunk of the third lumbar veins, and to the small continuation can be regarded as the proper IVC, and the part where the ureter hooks around it may have derived from the anastomosis between the common trunk of the third lumbar veins and the subcardinal vein.

Clinical predictors of success and failure for lumbar facet radiofrequency denervation

OBJECTIVE

To determine the clinical factors associated with the success and failure of radiofrequency denervation of the lumbar facet joints.

METHODS

Clinical data were garnered from 3 academic medical centers on 192 patients with low back pain who underwent radiofrequency denervation after a positive response to diagnostic blocks. Success was defined as >/=50% pain relief lasting at least 6 months. Factors evaluated for their association with outcome included duration of pain, opioid use, symptom location, paraspinal tenderness, pain exacerbated by extension/rotation (ie, facet loading), MRI abnormalities, diabetes, smoking, scoliosis, obesity, prior surgery and levels treated.

RESULTS

The only factor associated with a successful outcome was paraspinal tenderness. Variables that correlated with treatment failure were 'facet loading,' long duration of pain, and previous back surgery.

CONCLUSIONS

It is counterproductive to use 'facet loading' as the sole basis for choosing patients for facet interventions. In patients at high risk for treatment failure, taking additional steps to reduce the rate of false-positive screening blocks may improve outcomes.