Adjacent Spinous Processes Research Articles

Baastrup’s disease prevalence across various age groups and its association with degenerative changes: insights from STIR sequence in MRI

PurposeBaastrup’s disease is characterized by abnormal contact between adjacent spinous processes. Our study is the first to systematically incorporate the STIR sequence, recognized for its heightened sensitivity to fluid and edema, into the MRI protocol for diagnosing Baastrup’s disease in symptomatic individuals. The objective is to determine its prevalence and association with lumbar spinal degenerative changes.Materials and methodsLumbar spinal MRI examinations of 375 patients performed between January 2021 and 2022 were retrospectively reviewed by two radiologists. Baastrup’s disease was diagnosed based on meeting any of the following criteria: lumbar interspinous bursitis, hyperintense signal changes in adjacent spinous processes, and ligaments on the STIR sequence. The study also investigated the presence of degenerative changes and interreader agreement among radiologists.ResultsBaastrup’s disease was found in 141 of 375 individuals (37.8%). It correlated significantly with degenerative lumbar changes such as bulging (P = 0.0012), herniation (P = 0.0033), disc degeneration (P = 0.0013), Modic changes (P = 0.034), facet osteoarthritis (P = 0.0041), spinal stenosis (P = 0.005), and anterolisthesis (P = 0.0049). No significant associations were observed with gender (P = 0.468) or retrolisthesis (P = 0.167). Its occurrence increased gradually, peaking at 87.5% in individuals aged 80 and above. Radiologists showed complete agreement with Baastrup’s diagnoses.ConclusionBaastrup’s disease is more commonly observed than being considered rare, displaying an incremental occurrence with increasing age in symptomatic individuals notably discernible on the STIR sequence. Using the STIR sequence seems to promote a consensus among radiologists, irrespective of their experience levels.

Correlation between spinous process deviation and lumbar disc herniation in young patients

To explore the relationship between spinous process deviation and lumbar disc herniation in young patients. From March 2015 to January 2022, 30 treated young (under the age of 30) patients with lumbar disc herniation were included as the young group. In addition 30 middle-aged patients (quinquagenarian group) with lumbar disc herniation and 30 patients with non-degenerative spinal diseases (young non-degenerative group) were selected as control groups. The angle of the spinous process deviation was measured on CT and statistically analyzed by various groups. All the data were measured twice and the average value was taken and recorded. The average angle of spinous process deviation in the degenerative lumbar vertebra of young patients were (3.89±3.77) degrees, similar to the (3.72±2.98) degrees of quinquagenarian patients(P=0.851). The average angle of s spinous process deviation young non-degenerative group were (2.20±2.28) degrees, significantly less than young group(P=0.040). The spinous process deviation angle of the superior vertebral of the degenerative lumbar in the young group was (4.10±3.44) degrees, which similar to the (3.47±2.87) degrees in the quinquagenarian group (P=0.447). A total of 19 young patients had the opposite deviation direction of the spinous process of the degenerative lumbar vertebra and upper vertebra, while only 7 quinquagenarian patients had this condition(P=0.02). The type of lumbar disc herniation in young patients had no significant relationship with the direction of spinous process deflection of the degenerative or upper lumbar vertebra (P>0.05). Spinous process deviation is a risk factor of young lumbar disc herniation patients. If the deviation directions of adjacent lumbar spinous processes are opposite, it will increase the incidence of lumbar disc herniation in young patients. There was no significant correlation between the type of disc herniation and the deviation direction of the spinous process of the degenerative or upper lumbar vertebra. People with such anatomical variation can strengthen the stability of spine and prevent lumbar disc herniation through reasonable exercise.

Ventilatory failure in a cat following radical chest wall resection for feline injection site sarcoma

Case summaryA 12-year-old spayed female domestic shorthair cat presented for chest wall resection and radiation therapy following incomplete surgical excision of a feline injection site sarcoma. A CT scan for surgical planning was performed under general anesthesia and showed extensive tumor infiltration of the soft tissues of the right thorax. The cat recovered uneventfully from this anesthetic event. Nineteen days later, the patient was reanesthetized for forequarter amputation plus radical chest wall resection, including ribs 3–8 and all associated soft tissues plus adjacent spinous processes. Postoperatively, the patient developed acute respiratory failure secondary to hypoventilation. The cat was mechanically ventilated for 12 h prior to being successfully weaned from the ventilator. However, the improvement was transient and mechanical ventilation was reinitiated 6 h later owing to respiratory fatigue. On the second day, the cat developed unexplained central nervous system signs and was euthanized.Relevance and novel informationTo our knowledge, this is the first case report to describe ventilatory failure secondary to radical chest wall resection in a cat. Hypoventilation with subsequent need for mechanical ventilation is a potential complication that should be considered during preoperative planning in patients requiring extensive chest wall resections.

Full-Endoscopic Approach Forchronic Low Back Pain from Baastrup's Disease: Interspinous Plasty.

The objective was to introduce a new endoscopic technique‐interspinous plasty for low back pain from Baastrup's disease; based on clinical manifestations, imaging findings and diagnostic test, to discuss a detailed diagnostic procedure for Baastrup's disease; and to explore the mechanism of interspinous plasty in pain relief. To our knowledge, there is no report about the results of endoscopic lumbar technique for Baastrup's disease. This study described the successful full‐endoscopic surgical treatment for Baastrup's disease, providing a brand‐new therapeutic method for patients. Clinical manifestations, imaging findings, including X‐ray, computed tomography (CT) and magnetic resonance imaging, and a “positive” diagnostic test with local anesthetic were used to confirm Baastrup's disease in the three included patients. The interspinous plasty procedure, which aimed to recover a physiological gap between the adjacent spinous processes, was performed by full‐endoscopic resection of marginal osteophytes. The removal of local inflamed tissue and reducing inflammation via intraoperative saline irrigation also lead to pain relief. Clinical outcomes included visual analog scale (VAS) for low back pain and the Oswestry Disability Index (ODI). The distance between the adjacent spinous processes was measured from the preoperative and postoperative CT scan. We calculated and recorded the difference between preoperative and postoperative measurements. Technical procedures and advantages of interspinous plasty are introduced. The three patients showed improvement in terms of the postoperative VAS of low back pain (from 8 to 2, from 7 to 1 and from 8 to 2) and ODI (from 68.9% to 33.3%, from 77.8% to 28.9% and from 71.1% to 28.9%, respectively) at the 12‐month follow‐up. Compared postoperative ODI index, the ODI index increased from 26.7% to 33.3% and from 24.4% to 28.9% in two of the cases at the 12‐month follow‐up. At 1 week, CT confirmed an obvious reduction in the marginal osteophytes between the adjacent spinous processes. Compared with those on preoperative CT images, the distance between adjacent spinous processes on postoperative CT was enlarged from 1 to 4 mm, and a repeated CT scan 3 months later reconfirmed little recrudescent osteoproliferation. In selected cases, full‐endoscopic surgical treatment for chronic mechanical back pain as part of the phenomena of Baastrup's disease may be beneficial. The operations in this study were performed under local anesthesia, with satisfactory early clinical outcomes and a low incidence of complications or adverse events. This may be a feasible therapeutic method or an alternative option for patients who cannot tolerate general anesthesia surgery.

99. Radiographic assessment of fusion: a comparison of interbody spacers, following anterior cervical decompression and fusion

BACKGROUND CONTEXT While fusion in the context of anterior cervical discectomy and fusion (ACDF) has been reported to be as high as 97% at 4 years postop, little is known about the bridging of trabecular bone, radiolucency and interspinous motion (ISM) as definitive criterion for assessing fusion on radiographic X-ray imaging. While there is no conclusive method for quantifying interbody fusion (IBF), there is curiosity about whether these parameters can prove a spacer type to have a higher fusion rate than another. PURPOSE To determine whether the use of interbody cages (IC) promotes higher fusion rates in ACDF using plain X-ray studies. STUDY DESIGN/SETTING Single-center retrospective analysis of prospective consecutive database of multilevel ACDF. PATIENT SAMPLE This study included 94 patients and 232 levels were evaluated with 1-year postop images from August 2015 to November 2018. OUTCOME MEASURES Interspinous motion, bridging trabecular bone, fusion grade. METHODS A total of 32 published papers were reviewed to select the three best parameters for assessing cervical fusion: the passage of trabecula through the implant, the presence of a radiolucent line interfacing implant and vertebral plate, and the range of motion between two adjacent spinous processes. Radiolucency and bridging trabecular bone (BTB) parameters were combined to categorize each ACDF level as fused (≥75% BTB present) or not fused ( RESULTS A total of 234 surgical levels from 92 patients were included (age: 62.5, 42.4% F, BMI: 29.87). Median number of levels fused by patient was 2 (IQR: 1). Overall, 28.2% of the patients had at least 1 level with incomplete fusion. Patients with incomplete fusion (by BTM or ISM method) had longer ACDF than those with complete fusion (median=3 vs 2, p=0.022). No associations were found between demographic, smoking status and fusion rate (all p > 0.1). When investigating fusion level by level, using the BTB and ISM methods respectively, no significant differences were found based on IC type (bone graft vs cage; p=.867 and .585), iliac bone vs local (p =.869, .796) or allograft. Lower fusion rate was noticed for C6-C7 (58.1%) compared to more proximal disc spaces (71.4% to 78.7%, p = 0.049). Combination of IC and graft material revealed no significant difference (bonegraft + local=71.8% vs cage + iliac=66.7%, p = 0.517). Multivariate analysis, controlling for demographic and smoking status, demonstrated that only location of the fusion was an independent predictor of incomplete fusion. CONCLUSIONS There was no superiority within the allograft and autograft respective groups or between spacers, using the ISM or BTB techniques. More than 2mm of motion on dynamic X-ray studies, BTB and radiolucent interface between implant and endplates are efficient quantifiable methods to measure fusion on X-ray studies, as they are easily accessible and affordable within the health care field. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Adult lumbar spondylolisthesis: Interspinous devices

As minimally invasive surgery has become increasingly popular, interspinous process devices (IPDs) have evolved beyond cases of simple focal spinal stenosis. Despite design differences, all IPDs aim to achieve indirect decompression of the nerve roots by enlarging the caliber of the neural foramina via distraction of the adjacent spinous processes. Whether IPDs reduce the risk of adjacent level stenosis compared to decompression and fusion for degenerative spondylolisthesis remains unclear. Ultimately, the paucity of high-quality, long-term, comparative, clinical studies precludes any strong recommendation for the use of IPDs for the treatment of degenerative spondylolisthesis.

Successful use of percutaneous interspinous spacers and adjunctive spinoplasty in a 9 year cohort of patients

PurposeLumbar spinal canal stenosis and lumbar spinal foraminal stenosis are common, degenerative pathologies which can result in neurogenic claudication and have a negative impact on function and quality of life....

Anatomical and Biomechanical Study of the Lumbar Interspinous Ligament.

Objective:The lumbar interspinous ligaments (ISLs) are thin and short fibers connecting adjacent spinous processes. However, their morphology is variably described and their biomechanics are not well understood. Therefore, the purpose of this study was to assess the anatomy and biomechanics of the lumbar ISL.Materials and Methods:Five fresh frozen cadaveric specimens were dissected posteriorly to reveal and study the lumbar ISL. Measurements of the ligaments included the anterior vertical height (length A), the posterior vertical height (length P), and the length (length H) at each lumbar level. Next, 17 lumbar vertebral levels from 6 cadaveric specimens were used for tensile strength testing. The ISLs were subjected to vertically controlled increasing manual tension. The force necessary to disrupt the ISL was recorded.Results:All the ISLs ran horizontally in an anterior–posterior direction with a slight curve. The average of length A, length P, and length H on the right sides was 9.82, 9.57, and 20.12 mm, respectively. The average of length A, length P, and length H on the left sides was 11.56, 12.01, and 21.42 mm, respectively. The mean tensile strength of the ISL was 162.33 (N) at L1/2, 85.67 (N) at L2/3, and 79 (N) at L3/4. There was a significant difference in the tensile force between L1/2 and L2/3 and L1/2 and L3/4 (P < 0.05). The ligaments became weaker with a descent along the lumbar levels.Conclusion:The results of this study might help surgeons understand pathology/trauma of the lumbar vertebral region.

Extensive Degeneration of Vertebral Body Leading to Baastrup's Disease: A Radiographic Review of an Image.

Baastrup’s disease, known colloquially as “kissing spine disease”, is a degenerative process, most commonly occurring in the lumbar spine, in which adjacent spinous processes closely approximate or even touch (Filippiadis et al. in Insights Imaging. 10.1007/s13244-014-0376-7, 2015). We present the case of an 86-year-old woman presenting with left low back, hip, and anterolateral thigh pain. Magnetic resonance imaging noted an approximation of the L2/3 spinous processes, with degeneration of the vertebral processes. This article is based on previously conducted studies and does not contain any studies with human participants or animals performed by any of the authors. Informed consent for publication was obtained from the participant.

03:45 PM Abstract No. 194 Does lateral tilt during inferior vena cava filter placement result in subsequent need for advanced retrieval technique?

To investigate if lateral tilt during placement of an IVC filter is associated with lateral tilt during retrieval or need for advanced retrieval technique. Retrospective review of Gunther Tulip IVC filters placed and retrieved at our institution between 2015 and 2017 (n = 71) was performed after IRB approval. The angle between the filter and IVC was measured on pre-retrieval venogram (measured lateral tilt). Using the spinous processes of the adjacent vertebrae as an internal reference, calculated filter lateral tilt was then obtained by measuring the angle between the filter and spinous reference line (line connecting adjacent spinous processes) and the angle between IVC and spinous reference line. Intraclass correlation (ICC) analysis was performed using a two-way mixed effects ANOVA model to compare measured and calculated tilt demonstrating a high agreement between calculated and measured tilt angles (absolute ICC: 0.993, P<0.0001). Using this validated spinous process internal reference technique, the filter lateral tilt at time of placement was calculated using pre-placement venogram and intra-procedural post-placement spot radiograph. Filter retrievals were classified as standard (conventional snare) or advanced (technique other than conventional snare). Statistical analysis was performed using Stata for Mac v14.2. Dwell time-adjusted agreement between filter tilt angle at the time of placement and retrieval was fair (ICC coefficient = 0.57). Mean difference between tilt angle at the time of placement and retrieval was 4.4±4.2 degrees. A higher filter tilt angle during retrieval was significantly associated with advanced retrieval technique (P=0.026) while tilt angle during placement was not significantly associated with advanced retrieval technique (P=0.068). While higher lateral tilt of the Gunther Tulip filter measured at the time of retrieval is associated with the need for advanced retrieval technique, lateral tilt at the time of placement does not correlate with the need for advanced retrieval technique. Furthermore, lateral tilt at the time of placement is poorly associated with lateral tilt at the time of retrieval.

Minimally Invasive, Stereotactic, Wireless, Percutaneous Pedicle Screw Placement in the Lumbar Spine: Accuracy Rates With 182 Consecutive Screws.

Standard fluoroscopic navigation and stereotactic computed tomography-guided lumbar pedicle screw instrumentation traditionally relied on the placement of Kirshner wires (K-wires) to ensure accurate screw placement. The use of K-wires, however, is associated with a risk of morbidity due to potential ventral displacement into the retroperitoneum. We report our experience using a computer image-guided, wireless method for pedicle screw placement. We hypothesize that minimally invasive, wireless pedicle screw placement is as accurate and safe as the traditional technique using K-wires while decreasing operative time and avoiding potential complications associated with K-wires. We conducted a retrospective review of 42 consecutive patients who underwent a stereotactic-guided, wireless lumbar pedicle screw placement. All screws were placed to provide fixation to a variety of interbody fusion constructs including anterior lumbar interbody fusion, lateral interbody fusion, and transforaminal lumbar interbody fusion. The procedures were performed using the O-arm intraoperative imaging system with StealthStation navigation (Medtronic, Memphis, TN) and Medtronic navigated instrumentation. After placing a percutaneous navigation frame into the posterior superior iliac spine or onto an adjacent spinous process, an intraoperative O-arm image was obtained to allow subsequent StealthStation navigation. Para-median incisions were selected to allow precise percutaneous access to the target pedicles. The pedicles were cannulated using either a stereotactic drill or a novel awl-tipped tap along with a low-speed/high-torque power driver. The initial trajectory into the pedicle was recorded on the Medtronic StealthStation prior to removal of the drill or awl-tap, creating a "virtual" K-wire rather than inserting an actual K-wire to allow subsequent tapping and screw insertion. Accurate screw placement is achieved by following the virtual path as an exact computer-aided design model of the screw traversing the pedicle is projected onto the display and by using audible and tactile feedback. A second O-arm scan was obtained to confirm accuracy of screw placement. A total of 20 women and 22 men (average age = 56 years) underwent a total of 182 pedicle screw placements using the stereotactic, wireless technique. The total breach rate was 9.9%, with a clinically significant breach rate of 0% (defined as >2 mm medial breach or >4 mm lateral breach) and a clinical complication rate of 0%. Wireless, percutaneous placement of lumbar pedicle screws using computed tomography-guided stereotactic navigation is a safe, reproducible technique with very high accuracy rates.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P122. Cervical interbody spacer with passive radiographic fusion status indicator

BACKGROUND CONTEXT Pseudarthrosis or nonunion of the cervical spine is the result of failed attempted fusion and is a leading cause of postoperative axial pain and radiculopathy. Reported rates of failed cervical fusion range from 4.4 to 50%, generally higher with multilevel procedures, and pseudarthrosis accounts for 45%–56% of revision surgeries. Nonunion is difficult to detect clinically and diagnosis is based solely on symptomatology (neck pain, radiculopathy) and imaging studies. The gold standard approach to define fusion status involves surgical exploration, a last resort option. Radiographic tools are commonly used first, with computed tomography (CT) considered the most reliable method. However, CT scans are expensive and expose patients to large radiation doses (hundreds of times more than standard X-ray). The status of anterior cervical fusion can also be determined using interspinous motion analysis; the goal is to detect any movement between adjacent vertebra using dynamic radiographs. This may be accomplished by measuring the distance between the tips of adjacent spinous processes on lateral flexion and extension films. However, the technique is subjective and affected by parallax, and studies have found wide interobserver differences. This makes it difficult to accurately apply the method to assess pseudarthrosis using the proposed cutoff values (1 or 2 mm). Other literature similarly suggests that current radiographic methods do not reliably provide clinical information about abnormalities of intervertebral motion. Therefore quantitative and standardized methods for defining spinal fusion or instability are needed. PURPOSE Our hypothesis is that intervertebral motion can be more accurately detected using a simple passive implantable device that responds to the pressure differential or vertebral body endplate motion within the index disc space between the flexed and extended positions of the cervical spine. Conceptually, this dynamic motion sensor could detect and potentially prevent pseudarthrosis, a leading cause of postoperative pain and radiculopathy STUDY DESIGN/SETTING This desktop and benchtop research was conducted primarily in a chemistry laboratory. Manufacturing of prototypes and other materials was performed on-site. Radiographic images were taken at a centralized animal research facility. METHODS A cervical interbody spacer with integrated fluidic pressure sensor was developed using CAD modeling software and prototyped with 3D printing. The working principal involves a fluid well and indicator channel. The spacer was placed between Sawbones vertebra analogs and loads applied to simulate dynamic spinal positions. Previous work with a similar fluidics device used a single-column compression tester to apply loads comparable to those experienced by vertebra in the cervical region. Radiographs were also taken of a device loaded with radio-dense fluid (cesium acetate) and channel diameter of 0.5mm. RESULTS Computer simulations suggested that the device would fit and function well between cervical vertebra in the flexed and extended spinal positions. Prototypes placed between cervical bone analogs under load demonstrated that the signal would be apparent clinically. Previous work showed that fluid displacement into the indicator portion was in the appropriate scale (0–6.9 mm) under applied loads in the range experienced clinically (0–110 N); this relationship was linear and repeatable. The imaging resolution of the device with a radiocontrast agent as the indicator fluid was also within the clinical range, and the signal was apparent on radiographs. CONCLUSIONS Based on these results it appears that an interbody device with fluidic sensor is potentially a viable option for assessing fusion status in the cervical spine.Prior literature gives the range of loads expected in the cervical spine (up to ≈100N). Articles describing interspinous motion analysis suggest sufficient bone growth (fusion) occurs when the distance between the tips of adjacent cervical spinous processes changes by less than 1 mm or 2 mm between flexion and extension. Our concept offers two primary advantages over existing techniques. First, the indicator channel provides a clear and distinct signal or marker that can be plainly read on radiographs, simplifying comparisons between the flexed, neutral and extended positions and enabling monitoring over time. Second, the device introduces gain proportional to the ratio of the cross-sectional areas of the fluid well and channel, providing amplification and enabling detection of smaller changes. While a priori research demonstrated that an implantable fluidic device responded appropriately under the range of applied physiologic loads, if needed additional gain could be introduced by increasing this ratio. Future work involving finite element analysis and mechanical testing is underway and ultimately a cadaveric study will be conducted to verify the loads and characterize the device in vitro.Limitations of this work include the material choice as all prototypes were created using 3D printing. The flexural modulus of the material is important, and the device may potentially be formed with polycarbonate urethane, a stiffer and tougher flexible material commonly used in cervical disc replacements.

Management of irreducible unilateral facet joint dislocations in subaxial cervical spine: two case reports and a review of the literature

BackgroundSkeletal and soft tissue damage are often associated with unilateral facet dislocations, which undoubtedly lead to instability of the spine and further increase difficulties in cervical reduction. This type of irreducible facet dislocation is usually accompanied with potential catastrophic consequences including neurological deficit and severe disability. Therefore, a consistent and evidence-based treatment plan is imperative.Case presentationThe literature regarding the management of traumatic unilateral locked cervical facet dislocations was reviewed. Two patient cases (a 30-year-old Asian man and a 25-year-old Asian woman) who suffered irreducible cervical facet dislocations were presented. These two patients received surgical treatments including posterior reduction by poking facet joints, adjacent spinous process fixation by wire rope banding, anterior plate fixation, and intervertebral fusion after the failure of skull traction and closed reduction. At the postoperative 24-month follow-up, intervertebral fusion was achieved and our patients’ neurological status improved based on the American Spinal Injury Association scale, compared with their preoperative status.ConclusionsUnilateral facet joint dislocations of subaxial cervical spine are difficult to reduce when complicated with posterior facet fractures or ligamentous injury. Magnetic resonance imaging can be beneficial for identifying ventral and dorsal compressive lesions, as well as ligamentous or capsule rupture. The combination of posterior reduction and anterior fixation with fusion has advantages in terms of clinical safety, ease of operation, and less iatrogenic damage.

Different Interspinous Stabilization Systems: Market Evaluation

The interspinous spacers are those devices that placed between the spinous processes of contiguous vertebrae, act by dynamically stabilizing the vertebral segment in the sagittal plane. The principle of implanting a spacer between adjacent spinous processes was used by F. Knowles in the 1950s to discharge the posterior ring in patients with herniated discs and thus achieve pain relief [1,2]. Senegas et al. [3] who in 1986 designed a system of dynamic normalization stabilization (mechanical normalization system) to stiffen the degenerated lumbar segment operated, using an interspinous titanium block to limit the extension and a tension band (Dacron) around the spinous processes, to Secure the implant and limit bending. This implant, which was designed as the first generation of the current Wallis, so that it restored more physiological mechanical conditions in the treated degenerate segment, could not only alleviate or prevent the pain related to instability but decrease the range of disc destruction at that level. It was also suggested that if the interspinous stabilization system preserved more mobility in the treated segment than a fusion would do, then the degenerative process at adjacent levels would progress more slowly [4,5].

Optimal Point of Insertion and Needle Angle in Neuraxial Blockade Using a Midline Approach: A Study in Computed Tomography Scans of Adult Patients.

Neuraxial blockade using a midline approach can be challenging. Part of this challenge lies in finding the optimal approach of the needle to its target. The present study aimed at finding (1) the optimal point of insertion of the needle between the tips of 2 adjacent spinous processes and (2) the optimal angle relative to the skin at which the needle should approach the epidural or subarachnoid space. A computer algorithm systematically analyzed computed tomography scans of vertebral columns of a cohort of 52 patients. On midsagittal sections, the possible points of insertion of a virtual needle and the corresponding angles through which the epidural or subarachnoid space can be reached were calculated. The point chosen to introduce the needle between 2 adjacent spinous processes determines the range of angles through which the epidural or subarachnoid space can be reached. At the thoracic interspaces 1-2 through 3-4, thoracic interspaces 5-6 through 9-10, and at the lumbar vertebral interspaces 2-3 through 4-5, the optimal point of insertion is slightly inferior to the point halfway between the tips of the spinous processes. For thoracic interspace 4-5, the optimal point of insertion is slightly superior to the point halfway between the tips of the spinous processes. For the other interspaces, the optimal point of insertion is approximately halfway between the tips of the spinous processes. The optimal angle to direct the needle varies from 9 degrees at the thoracolumbar junction and at the lumbar interspaces 3-4 and 4-5, to 53 degrees at the thoracic interspace 7-8. Our study has resulted in practical suggestions-based on accurate, reproducible measurements in patients-as to where to insert the needle and how to angulate the needle when performing neuraxial anesthesia using a midline approach.

Prevalence and distribution of ossification of the supra/interspinous ligaments in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine: a CT-based multicenter cross-sectional study.

BackgroundSupra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL).MethodsThe participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated.ResultsA total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients.ConclusionsThe prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

Baastrup Disease/Interspinous Bursitis

Baastrup disease (BD), an uncommon back pain syndrome, is characterized by pathologic approximation of adjacent spinous processes on a sagittal plane image. BD occurs most commonly at the lumbar L4-L5 level and tends to be more common in the elderly. The etiology is not precisely known, but BD may develop secondary to chronic active inflammatory facet arthropathy, leading to interspinous osteophytes and approximation of the adjacent spinous processes. Clinically, BD should be considered in the differential diagnosis of back pain if there is (1) midline back pain reproduced with palpation of the spinous process and exacerbated by extension of the lumbar spine and (2) direct contact of adjacent spinous processes on the lateral view of a plain x-ray image. Magnetic resonance imaging is more sensitive in detecting interspinous inflammation and the formation of bursa and new bone. Major differential diagnoses of BD include proliferative hyperostosis of the lumbar spinous processes, degenerative disease of the spine, sclerotic bone metastases to the spine, and ankylosing spondylosis. BD can be managed initially with nonsteroidal antiinflammatory drugs, a short-term steroid dose pack, and physical therapy. Injection of a local anesthetic to the inflamed spinous process and associated interspinous ligaments may be diagnostic, and injection of a local anesthetic/corticosteroid combination may be therapeutic. Surgery is reserved for patients with refractory BD. Surgical options include interspinous process decompression devices and excision of the affected spinous processes.

Optimal point of insertion of the needle in neuraxial blockade using a midline approach: study in a geometrical model.

Performance of neuraxial blockade using a midline approach can be technically difficult. It is therefore important to optimize factors that are under the influence of the clinician performing the procedure. One of these factors might be the chosen point of insertion of the needle. Surprisingly few data exist on where between the tips of two adjacent spinous processes the needle should be introduced. A geometrical model was adopted to gain more insight into this issue. Spinous processes were represented by parallelograms. The length, the steepness relative to the skin, and the distance between the parallelograms were varied. The influence of the chosen point of insertion of the needle on the range of angles at which the epidural and subarachnoid space could be reached was studied. The optimal point of insertion was defined as the point where this range is the widest. The geometrical model clearly demonstrated, that the range of angles at which the epidural or subarachnoid space can be reached, is dependent on the point of insertion between the tips of the adjacent spinous processes. The steeper the spinous processes run, the more cranial the point of insertion should be. Assuming that the model is representative for patients, the performance of neuraxial blockade using a midline approach might be improved by choosing the optimal point of insertion.

Morphology of the thoracolumbar spine of the middle Miocene hominoid Nacholapithecus kerioi from northern Kenya

A new caudal thoracic and a new lumbar vertebra of Nacholapithecus kerioi, a middle Miocene hominoid from northern Kenya, are reported. The caudal thoracic vertebral body of N. kerioi has a rounded median ventral keel and its lateral sides are moderately concave. The lumbar vertebral body has an obvious median ventral keel. Based on a comparison of vertebral body cranial articular surface size between the caudal thoracic vertebrae in the present study and one discussed in a previous study (KNM-BG 35250BO, a diaphragmatic vertebra), N. kerioi has at least two post-diaphragmatic vertebrae (rib-bearing lumbar-type thoracic vertebrae), unlike extant hominoids. It also has thick, rounded, and moderately long metapophyses on the lumbar vertebra that project dorsolaterally. The spinous process bases of its caudal thoracic and lumbar vertebrae originate caudally between the postzygapophyses, as described previously in the KNM-BG 35250 holotype specimen. In other words, the postzygapophyses of N. kerioi do not project below the caudal border of the spinous processes, similar to those of extant great apes, and unlike small apes and monkeys, which have more caudally projecting postzygapophyses. Nacholapithecus kerioi has a craniocaudally expanded spinous process in relation to vertebral body length, also similar to extant great apes. Both these spinous process features of N. kerioi differ from those of Proconsul nyanzae. The caudal thoracic vertebra of N. kerioi has a caudally-directed spinous process, whose tip is tear-drop shaped. These features resemble those of extant apes. The morphology of the spinous process tips presumably helps vertebral stability by closely stacking adjacent spinous process tips as seen in extant hominoids. The morphology of the spinous process and postzygapophyses limits the intervertebral space and contributes to the stability of the functional lumbar region as seen in extant great apes, suggesting that antipronograde activity was included in the positional behavior of N. kerioi.

A sesamoid ossicle of the nuchal ligament mimicking spinous avulsion fracture

A 25-year-old man who suffered a traffic accident was admitted to our emergency department. Computer tomography was performed. Computer tomography images showed an osseous structure mimicking avulsion fracture at the level of C5–C6 (Fig. 1). There was no bone defect corresponding to spinous process and so, the diagnosis was consistent with sesamoid ossicles of the nuchal ligament. Sesamoid ossicles of the nuchal ligament are an anatomical variant that are usually asymptomatic. Prominent differential diagnosis includes avulsion fractures of the spinal processes and myositis ossificans. Focal well-defined osseous masses, well-circumscribed with regular shape, are in favor of sesamoid ossicle of nuchal ligament, whereas triangular dense bony fragment with bony defect of the adjacent spinous process are in favor of spinous process fracture. Ihsan Yuce, MD Berhan Pirimoglu, MD Gokhan Polat, MD Recep Sade, MD Mucahit Emet, MD Mecit Kantarci, MD, PhD Department of Radiology, School of Medicine Ataturk University 25100 Erzurum, Turkey Department of Emergency Medicine, School of Medicine Ataturk University 25100 Erzurum, Turkey