Ultrasound-guided lumbar facet nerve block: accuracy of a new technique confirmed by computed tomography

BACKGROUND: Lumbar facet nerve (medial branch) blocks are often used to diagnose facet joint-mediated pain. The authors recently described a new ultrasound-guided methodology. The current study determines its accuracy using computed tomography scan controls. METHODS: Fifty bilateral ultrasound-guided approaches to the lumbar facet nerves were performed in five embalmed cadavers. The target point was the groove at the cephalad margin of the transverse (or costal) process L1-L5 (medial branch T12-L4) adjacent to the superior articular process. Axial transverse computed tomography scans, with and without 1 ml contrast dye, followed to evaluate needle positions and spread of contrast medium. RESULTS: Forty-five of 50 needle tips were located at the exact target point. The remaining 5 were within 5 mm of the target. In 47 of 50 cases, the applied contrast dye reached the groove where the nerve is located, corresponding to a simulated block success rate of 94% (95% confidence interval, 84-98%). Seven of 50 cases showed paraforaminal spread, 5 of 50 showed epidural spread, and 2 of 50 showed intravascular spread. Despite the aberrant distribution, all of these approaches were successful, as indicated by contrast dye at the target point. Abnormal contrast spread was equally distributed among all lumbar levels. Contrast traces along the needle channels were frequently observed. CONCLUSIONS:: The computed tomography scans confirm that our ultrasound technique for lumbar facet nerve block is highly accurate for the target at all five lumbar transverse processes (medial branches T12-L4). Aberrant contrast medium spread is comparable to that of the classic fluoroscopy-guided method.     

Ultrasound-guided lumbar facet nerve block: a sonoanatomic study of a new methodologic approach

BACKGROUND: Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility. METHODS: (1) A paravertebral cross-axis view and long-axis view were defined under high-resolution ultrasound (15 MHz). Three needles were guided to the target point at L3-L5 in a fresh, nonembalmed cadaver under ultrasound (2-6 MHz) and were subsequently traced by means of dissection. (2) The lumbar regions of 20 volunteers (9 women, 11 men; median age, 36 yr [23-67 yr]; median body mass index, 23 kg/m2 [19-36 kg/m2]) were studied with ultrasound (3.5 MHz) to assess visibility of landmarks and relevant distances at L3-L5 in a total of 240 views. (3) Twenty-eight ultrasound-guided blocks were performed in five patients (two women, three men; median age, 51 yr [31-68 yr]) and controlled under fluoroscopy. RESULTS: In the cadaver, needle positions were correct as revealed by dissection at all three levels. In the volunteers, ultrasound landmarks were delineated as good in 19 and of sufficient quality in one (body mass index, 36 kg/m2). Skin-target distances increased from L3 to L5, reaching statistical significance (*, **P < 0.05) between these levels on both sides: L3r, 45+/-6 mm*; L4r, 48+/-7 mm; L5r, 50+/-6 mm*; L3l, 44+/-5 mm**; L4l, 47+/-6 mm; L5l, 50+/-6 mm**. In patients, 25 of 28 ultrasound-guided needles were placed accurately, with the remaining three closer than 5 mm to the radiologically defined target point. CONCLUSION: Ultrasound guidance seems to be a promising new technique with clinical relevance and the potential to increase practicability while avoiding radiation in lumbar facet nerve block.     

Ultrasound-guided Lumbar Facet Nerve Block: A Sonoanatomic Study of a New Methodologic Approach

Background: Lumbar facet nerve (medial branch) block for pain relief in facet syndrome is currently performed under fluoroscopic or computed tomography scan guidance. In this three-part study, the authors developed a new ultrasound-guided methodology, described the necessary landmarks and views, assessed ultrasound-derived distances, and tested the clinical feasibility.

Methods: (1) A paravertebral cross-axis view and long-axis view were defined under high-resolution ultrasound (15 MHz). Three needles were guided to the target point at L3-L5 in a fresh, nonembalmed cadaver under ultrasound (2-6 MHz) and were subsequently traced by means of dissection. (2) The lumbar regions of 20 volunteers (9 women, 11 men; median age, 36 yr [23-67 yr]; median body mass index, 23 kg/m2 [19-36 kg/m2]) were studied with ultrasound (3.5 MHz) to assess visibility of landmarks and relevant distances at L3-L5 in a total of 240 views. (3) Twenty-eight ultrasound-guided blocks were performed in five patients (two women, three men; median age, 51 yr [31-68 yr]) and controlled under fluoroscopy.

Results: In the cadaver, needle positions were correct as revealed by dissection at all three levels. In the volunteers, ultrasound landmarks were delineated as good in 19 and of sufficient quality in one (body mass index, 36 kg/m2). Skin-target distances increased from L3 to L5, reaching statistical significance (*, **P < 0.05) between these levels on both sides: L3r, 45 +/- 6 mm*; L4r, 48 +/- 7 mm; L5r, 50 +/- 6 mm*; L3l, 44 +/- 5 mm**; L4l, 47 +/- 6 mm; L5l, 50 +/- 6 mm**. In patients, 25 of 28 ultrasound-guided needles were placed accurately, with the remaining three closer than 5 mm to the radiologically defined target point.     

Ultrasound guidance for facet joint injections in the lumbar spine: a computed tomography-controlled feasibility study

We conducted this study to develop an ultrasound-guided approach for facet joint injections of the lumbar spine. Five zygapophyseal joints (L1-S1) on each side of 5 embalmed cadavers were examined by ultrasound for a total of 50 examinations. The joint space was demonstrated under ultrasound guidance. The midpoint of the joint space, defined as the middle of its cranio-caudal extension on its dorsal surface, was taken as a reference point, and its position was computed from its depth and lateral distance from the spinous process. Forty-two of 50 approaches could be clearly visualized. Subsequently, these distances were compared to those obtained by computed tomography (CT). To assess the efficacy of ultrasound in the needle placement, all lumbar facet joints were approached in one embalmed cadaver. The exact placement of the needle tips was again evaluated by CT. Ultrasound and CT measurements showed the same mean depth and lateral distance to the reference point, 3.15 +/- 0.5 cm and 1.9 +/- 0.6 cm, respectively. Pearson's coefficient of correlation was 0.86 (P < 0.0001) between ultrasound and CT. All 10 needle tips were within the joint space during simulated facet joint injections. We conclude that ultrasound guidance might be a useful adjunct for facet joint injections in the lumbar spine. IMPLICATIONS: This study was designed to develop an ultrasound-guided approach to the facet joints of the lumbar spine and to assess its feasibility and accuracy by means of a comparison to computed tomography images. The imaging study demonstrated a significant correlation between ultrasound and computed tomography measurements. During simulated facet injection, ultrasound guidance consistently resulted in accurate needle placement.     

Ultrasound-guided lumbar medial-branch block: a clinical study with fluoroscopy control

BACKGROUND AND OBJECTIVES: For diagnostic lumbar medial-branch blocks, fluoroscopic guidance is considered mandatory, but this technique comes with radiation exposure. The clinical feasibility of the ultrasound-guided lumbar medial-branch block has been demonstrated. We evaluated the success rate and validity of this new method by use of fluoroscopy controls in patients previously diagnosed with lumbar facet joint-mediated pain. METHODS: In 20 patients, 101 lumbar medial-branch blocks were performed under ultrasound guidance. The target point was the groove at the cephalad margin of the transverse process adjacent to the superior articular process. C-arm fluoroscopy was performed afterward to confirm the needle position. Pain scores were assessed by use of visual analog scale (VAS 0 to 100). RESULTS: All 101 needles were placed in the correct lumbar segment. Ninety-six of the 101 needletips were in the correct position with a success rate of 95%. Two needles were associated with intravascular spread of the contrast dye. VAS score was reduced from 52 to 16 after the block. CONCLUSIONS: Ultrasound-guided lumbar medial-branch blocks can be performed with a high success rate. However, to be completely independent from fluoroscopy controls, this technique requires further studies regarding the detection of intravascular spread.     

Percutaneous radiofrequency lumbar facet rhizotomy guided by computed tomography fluoroscopy

X-ray fluoroscopy-guided percutaneous radiofrequency facet rhizotomy is used to treat chronic low back pain. The traditional fluoroscopic approach to the medial branch of the posterior rami, however, is associated with a small incidence of complications. We describe a new method for radiofrequency lumbar facet rhizotomy in which computed tomography (CT) fluoroscopy is used to guide needle placement. Three patients with chronic intractable low back pain underwent CT fluoroscopy-guided percutaneous facet rhizotomy. After the safest and shortest route to the target site was determined on the CT image, the needle was advanced along the predetermined route under real-time CT fluoroscopy. When the needle tip was located at the target site, electrical stimulation was applied to verify proper electrode placement. After confirming the clinical effect and lack of complications under test block with a local anesthetic, denervation was performed using radiofrequency current. Pain scores of all patients were reduced after the procedure without any complications such as paralysis or neuritic pain. None of the patients complained of severe discomfort during the procedure. CT fluoroscopy-guided percutaneous lumbar facet rhizotomy appears to be safe, fast, and effective for patients with lumbar facet pain.     

Transverse Process and Needles of Medial Branch Block to Facet Joint as Landmarks for Ultrasound-Guided Selective Nerve Root Block

Background

Selective lumbar nerve root block (SNRB) is generally accepted as an effective treatment method for back pain with sciatica. However, it requires devices producing radioactive materials such as C-arm fluoroscopy. This study evaluated the usefulness of the longitudinal view of transverse process and needles for medial branch block as landmarks under ultrasonography.

Methods

We performed selective nerve root block for 96 nerve roots in 61 patients under the guidance of ultrasound. A curved probe was used to identify the facet joints and transverse processes. Identifying the lumbar nerve roots under the skin surface and ultrasound landmarks, the cephalad and caudal medial branch blocks were undertaken under the transverse view of sonogram first. A needle for nerve root block was inserted between the two transverse processes under longitudinal view, while estimating the depth with the needle for medial branch block. We then injected 1.0 mL of contrast medium and checked the distribution of the nerve root with C-arm fluoroscopy to evaluate the accuracy. The visual analog scale (VAS) was used to access the clinical results.

Results

Seven SNRBs were performed for the L2 nerve root, 15 for L3, 49 for L4, and 25 for L5, respectively. Eighty-six SNRBs (89.5%) showed successful positioning of the needles. We failed in the following cases: 1 case for the L2 nerve root; 2 for L3; 3 for L4; and 4 for L5. The failed needles were positioned at wrong leveled segments in 4 cases and inappropriate place in 6 cases. VAS was improved from 7.6 ± 0.6 to 3.5 ± 1.3 after the procedure.

Conclusions

For SNRB in lumbar spine, the transverse processes under longitudinal view as the ultrasound landmark and the needles of medial branch block to the facet joint can be a promising guidance.     

Anatomical description of the facet joint innervation and its implication in the treatment of recurrent back pain

AIM: Many techniques are used in the back pain treatment, standing out the facet denervation as a therapeutic option for pain that originates in the facet joints. It's known that the facet joint is an abundant area of nocireceptor innervation, although the distribution and the location of the involved branches have not being well demonstrated. A good comprehension about the affected innervation is very important to get an effective treatment. Purpose of study was to describe innervation of the lumbar facet joints, potentially used in the diagnosis and treatment of painful pictures of the lumbar region by facet syndrome. Study design: anatomical study of nerve roots distribution of the facet joint 3 human corpses. The determination of the neurotomy s point was carried out by direct visualization and the radiological study in human parts. METHODS: Three anatomical pieces of the human lumbar spine were dissected. In those 3 pieces, the facet joint innervation distribution was studied thoroughly using surgical microscope and microsurgical technique. In one of the pieces the needles positioning was first made to test through the radiological study the possible application of the precise denervation in low back pain treatment. RESULTS: The L1 to L4 segments, each dorsal branch of root emits a medial branch that emerges from intertransversal ligament. This branch crosses the superior margin of the medial termination of transverse process, passing through the root of the superior articulate process. Each branch innerves the anterior region of the inferior facet and the inferior portion of articulation which one spins around. The L5 dorsal branch was larger than the superior branches. It emerges dorsally and in the inferior region on top of the sacrum wing. This nerve is in the bone fissure of the junction between the wing and the posterior region of the sacrum articular process. Near the inferior portion of the articular process, the nerve ramifies itself in lateral and medial branch. The medial branch comes back around the inferior portion of the lumbar-sacrum articulation that it innervates. CONCLUSIONS: We didn't note great variations in the anatomy from L1 do L4. The L5 segment has a different distribution of the branches that should be considered when we do a percutaneous denervation procedure. The approach of the needle must touch the transverse process and feels the resistance of the articular joint . The determination of the neurotomy s point tends to become more precise denervation procedure.     

The surgical anatomy of thoracic facet denervation

Summary Thoracic percutaneous facet denervation has been employed for the treatment of thoracic zygapophysial joint pain. But the surgical anatomy of this procedure has been assumed to be the same as for lumbar medial branch neurotomy. To establish the anatomical basis for thoracic medial branch neurotomy, an anatomical study was undertaken. Using an X40 dissecting microscope, a total of 84 medial branches from 7 sides of 4 embalmed human adult cadavers were studied.The medial branches of the thoracic dorsal rami were found to assume a reasonably constant course. Upon leaving the intertransverse space, they typically crossed the superolateral corners of the transverse processes and then passed medially and inferiorly across the posterior surfaces of the transverse processes before ramifying into the multifidus muscles. Exceptions to this pattern occurred at mid-thoracic levels (T5–T8). Although the curved course remained essentially the same, the inflection occurred at a point superior to the superolateral corner of the transverse process.At no time during the dissection were nerves encountered crossing the junctions between the superior articular processes and transverse processes which have been the target points advocated for thoracic facet denervation. Rather, the results of this study indicate that the superolateral corners of the transverse processes are more accurate target points.     

Ultrasound-guided periradicular injections in the middle to lower cervical spine: an imaging study of a new approach

BACKGROUND AND OBJECTIVES: The objective of this study was to show the efficacy of ultrasound in facilitating the performance of a simulated cervical periradicular injection in cadavers. METHODS: A total of 40 ultrasound-guided examinations at 4 levels (C3 to C7) were performed on 4 embalmed cadavers. The cervical spinal nerves were located with ultrasound. First, the transverse process of each level was taken as a sonoanatomic landmark. The most lateral aspect of the transverse process of the seventh cervical vertebra was then established as the reference point. Ipsilateral distances (A, B, C, and D) between this point and each one of the transverse processes of the cervical spine up to the third vertebra were then computed. Subsequently, coronal computed tomography (CT) scans were taken to verify these distances. In a second part, a spinal needle was advanced under ultrasound guidance to the spinal nerves C5 to C8 on both sides of one cadaver. The exact placement of the needle tips was checked by CT. RESULTS: The transverse processes were identified in all cadavers. In 5 attempts, a depiction of the spinal nerves was not possible. Ultrasound and CT provided the same mean measurements of 1.1 cm, 2.1 cm, 3.1 cm, and 4.1 cm for distances A, B, C, and D, respectively. All 8 needle tips were placed within 5 mm dorsal to the spinal nerve and less than 5 mm away from the posterior tubercle of each level's transverse process, as also verified by CT. CONCLUSIONS: This preclinical study suggests that ultrasound is a useful guiding tool for periradicular injections in the cervical spine.     

Facet joint asymmetry and protrusion of the intervertebral disc

In a study of 47 cases of lumbar disc protrusion, the hypothesis that asymmetry of the facet joints is correlated with the presence of a disc protrusion, was tested. Seventeen cases of protrusion of the L4-L5 disc and 30 cases of protrusion of the L5-S1 disc were measured on coronal computed tomography (CT) scans. The nonprotruded discs of each level were used as controls of the protruded discs of the same level. The transverse interfacet angle, the inclination and curvature of the facet joints, and the frequency of asymmetric facet joints showed no significant differences, whether there was a disc protrusion or not. The magnitude of the asymmetry was significantly greater only at the L4-L5 interspace in cases of disc protrusion. However, taking into consideration the error of measurement, the difference becomes highly questionable. These results do not indicate any relation between facet joint asymmetry and protrusion of the intervertebral disc.     

Primary sensory neurons with dichotomizing axons projecting to the facet joint and the sciatic nerve in rats.

STUDY DESIGN: Dorsal root ganglion (DRG) neurons that have dichotomizing axons to the lumbar facet joint and to the sciatic nerve were investigated in rats using a double fluorescent labeling technique. OBJECTIVES: To clarify the existence of DRG neurons with dichotomizing axons projecting to the lumbar facet joint and to the sciatic nerve in rats. SUMMARY OF BACKGROUND DATA: DRG neurons having dichotomizing axons have been reported in several species and are considered to be related to referred pain. However, such DRG neurons have not been investigated in the lumbar spine. Clinically, pain from the lumbar facet joint is sometimes referred to the lower extremities innervated by the sciatic nerve. METHODS: Two kinds of neurotracers (DiI and FG) were used in the present double-labeling study. DiI crystals were placed in the left L5-L6 facet joint, and FG was applied to the ipsilateral sciatic nerve or along the midline of the L5 dermatome. Bilateral DRGs T13-S1 were observed by fluorescence microscope. RESULTS: DRG neurons double labeled with DiI and FG were recognized only in the ipsilateral DRGs from L3 to L6 levels. Approximately 3% of DRG neurons innervating the L5-L6 facet joint had other axons to the sciatic nerve. By contrast, no double-labeled neurons were observed after FG was applied to the L5 dermatome. CONCLUSIONS: In rats approximately 3% of DRG neurons innervating the lumbar facet joints have dichotomized axons projecting to the sciatic nerve.     

Influence of needle position on lumbar segmental nerve root block selectivity

BACKGROUND AND OBJECTIVES: In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. METHODS: Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). RESULTS: Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). CONCLUSION: The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.     

Electrical stimulation of the rat lumbar spine induces reflex action potentials in the nerves to the lower abdomen

STUDY DESIGN: The distribution of the nerve action potentials reflexively elicited by electrical stimulation of the lumbar spine was investigated in rats. OBJECTIVES: To elucidate the relation between the lumbar spine and other body regions that compose the spinal reflex. SUMMARY OF BACKGROUND DATA: The hypothesis was that the ventral portion of the L5-L6 disc spatially corresponds to the groin. METHODS: In Experiments 1 and 2, wire electrodes were placed 1) in the ventral and dorsal portions of the disc, facet joint, and muscle fascia at L5-L6, and 2) in the ventral portions of L3-L4, L4-L5, L5-L6, and L6-S discs. A needle electrode was inserted in the L5-L6 disc by 0.4-mm increments, and action potentials were serially recorded from the genitofemoral nerve. RESULTS: Experiments 1 and 2: Reflex action potentials were elicited in the iliohypogastric (T13 and L1), ilioinguinal (L1), and genitofemoral (L2) nerves. Experiment 1: Stimulation of the disc induced reflex discharges significantly more frequently than stimulation of the facet joint and muscle fascia. Experiment 2: The more cranial the disc stimulated, the more frequently the reflex discharge was induced in the iliohypogastric nerve. Experiment 3: The depth of stimulation did not influence the size of the reflex action potential. CONCLUSIONS: Electrical stimulation of the lumbar disc and facet joint induced reflex discharges in the nerves to the lower abdominal regions. It was postulated that the reflex discharges are related to muscle contraction resulting in referred pain in the loin and groin.     

Modified Lateral Block of the Suprascapular Nerve: A Safe Approach and How Much to Inject? A Morphological Study

BACKGROUND AND OBJECTIVES: This paper presents an evaluation of a modified lateral suprascapular nerve block with easy orientation, low risk of displacement of the needle, and with an assessment of 2 different volumes to propose an ideal volume for a successful block. METHODS: Both shoulders of 34 cadavers were investigated. Insertion point of the needle was determined in the angle of the lateral end of the clavicle, acromion, and the spine of the scapula. The needle was directed toward the medial, dorsal, and caudad direction. Ten mL of diluted contrast agent for computerized tomography was injected in the 34 right sides (group A) and 5 mL in the 34 left sides (group B). Immediately after injection, all shoulders were investigated by computerized tomography scans and 3-dimensional reconstruction to document the constrast dissemination. Five sides of each group were injected with colored contrast and dissected after computerized tomography investigation. RESULTS: Group A showed a distribution to the entire supraspinous fossa in all cases and the contrast was pressed out of the suprascapular notch in 4 cases with a maximal extension into the axillary fossa in 3 cases. In group B, the supraspinous fossa was filled in 24 cases, with a maximal extension to the axillary fossa in 2 cases. In 9 cases, the contrast agent stayed in the lateral half of the supraspinous fossa. In 1 case we had a medial spread only which still surrounded the suprascapular notch, in another case a superficial spread with misplacement of the needle. CONCLUSION: Based on this cadaver study, the lateral modified approach appears to be a safe technique for a suprascapular nerve block, which might be preferred as a single shot technique. A 5 mL volume appears sufficient to fill the supraspinous fossa and to reach the suprascapular nerve, which branches in this anatomical compartment.     

Misplacement of a psoas compartment catheter in the subarachnoid space

BACKGROUND AND OBJECTIVES: This case report describes an unusual cause of misplacement of an indwelling catheter in the subarachnoid space after primary psoas compartment block in a patient undergoing total knee arthroplasty. CASE REPORT: A 67-year-old woman presenting for total knee joint replacement received a combination of continuous psoas compartment block and sciatic nerve block. Neurostimulation and additional ultrasound guidance were used for identification of the lumbar plexus. After elicitation of a quadriceps motor response, a negative aspiration test, and an uneventful test dose, 20 mL ropivacaine 0.375% and 20 mL mepivacaine 1% were injected. Despite difficult ultrasound conditions because of intestinal air, local anesthetic spread was observed paravertebrally at the medial border of the psoas muscle as usual. A catheter was then advanced 7 cm through the insulated directional puncture needle. An additional sciatic nerve block was performed by using Labat's approach. Ten minutes after injection unilateral sensory block was noted and surgery was started. After uneventful surgery, bilateral sensory block to the T4 level and complete motor block in both lower limbs was detected. A second aspiration test was negative, and an epidural block was suspected. For verification of the catheter tip location, a computed tomography scan with contrast dye was performed revealing catheter placement in the subarachnoid space. The catheter was removed and showed a kink about 7 cm from the tip. After regression of the neuraxial block, lumbar plexus block persisted for another 2 hours. CONCLUSION: An additional test dose via the catheter is recommended if the indwelling catheter is inserted after injection of the local anesthetics through the puncture needle. If epidural anesthesia occurs, an x-ray of the catheter is advisable because negative aspiration via catheter does not rule out subarachnoid catheter location.     

腰后关节紊乱症与腰脊神经后内侧支关系的临床与实验研究

给出了一个解线性规划的有效集方法，此方法有以下几个待征：①对初始点不做任何要求；②每次迭代可能增加或减少多个约束，此将有利于提高收敛速度。     

Ultrasound-guided cervical facet joint injections

BACKGROUND CONTEXTCervical facet joints are a common cause of chronic neck pain. Radiofrequency neurotomy is a validated treatment technique for cervical facet joint pain, but the role of intra-articular injections is less clear. Ultrasound guidance can be used to inject the cervical facet joints. Given that the accuracy of any injection technique is likely to affect treatment outcomes, it would be useful to know the accuracy of ultrasound-guided cervical facet joint injections.PURPOSEThe primary purpose of this study was to determine the accuracy of ultrasound-guided cervical facet joint injections using a lateral technique. The secondary purpose was to describe the technique.STUDY DESIGN/SETTINGCohort study of ultrasound-guided cervical facet joint injections performed by an experienced spine and ultrasound interventionist, as assessed by contrast dye arthrography at a community interventional spine practice.PATIENT SAMPLESixty joints in 36 patients with facet mediated pain.OUTCOME MEASURESAccuracy of ultrasound-guided injections as determined by the percent of fluoroscopic contrast dye patterns interpreted to be intra-articular by the operator and an independent imaging specialist. Confidence intervals were determined using binomial “exact” and normal approximation to the binomial calculations.METHODSUltrasound using a long-axis or in-plane approach was used to guide a needle into a facet joint, followed by injection of contrast dye and a lateral fluoroscopic image. The dye pattern was interpreted by the operator. Depending on the pattern, local anesthetic and corticosteroid were injected. The patient was asked whether their neck pain had resolved. If not resolved, another joint was selected and the process was repeated. At the end of the study, all of the contrast patterns were interpreted independently by the imaging specialist. Funding was through a 501(c)(3) foundation without any commercial or sponsorship interests.RESULTSThe accuracy of ultrasound-guided cervical facet joint injections using the lateral technique ranged from 92% to 98% depending on the criteria used to confirm an intra-articular contrast pattern (95% CI: 0.82–0.97 to 0.91–1.0, and 0.85–0.99 to 0.95–1.00). The distribution of injections was C2–3 (22%), C3–4 (40%), C4–5 (33%) and C5–6 (5%).CONCLUSIONSCervical facet joint injections can be performed with a high degree of accuracy using a lateral ultrasound-guided technique. As with fluoroscopy-guided cervical facet joint injections, the technique requires a careful approach and a high degree of skill.     

The orientation of laminae and facet joints in the lower lumbar spine

The relationship between the angulation of the facet joints and that of the caudad parts of the corresponding laminae in the transverse plane was investigated with computed tomography (CT) at the vertebral levels L3-L4, L4-L5, and L5-S1. At the level of L3-L4, both the facet joints and the caudad portions of the laminae tend toward a sagittal orientation, while at L5-S1 this is more toward the frontal plane. At the level of L4-L5, they occupy an intermediate position. A highly significant correlation between the orientation of these structures is demonstrated. The caudad parts of the laminae may be considered buttresses for the inferior articular processes of the same vertebra.     

Curvature of the lower lumbar facet joints: variations at different levels and relationship with orientation.

The curvature of the lower lumbar facet joints in the transverse plane was measured using an innovative computed tomographic approach, and its relationship with the orientation of the joints was evaluated. Two hundred three vertebral levels were examined in 116 patients with low back pain. Reference circles were used to quantify joint curvature. The mean curvature (+/- SD) at the levels L3-L4, L4-L5, and L5-S1 conformed to circles of 27.3 mm +/- 11.5; 35.1 mm +/- 14.6; and 51.0 mm +/- 34.5 in diameter respectively. The ratio between the curvature of the facets and their orientation was 62.6% +/- 19.0; 57.8% +/- 21.6; and 64.9% +/- 48.9. From L3-L4 down to L5-S1 the curvature of the facet joints decreases. The differences between L3-L4 and L4-L5 is smaller than between L4-L5 and L5-S1. The curvatures of the joints conform to circles that are in mean approximately 40% in diameter smaller than those to which their orientations conform.