Ventral Compression Research Articles

Historical Control Background Incidence of Spontaneous Nonneoplastic Lesions of Sprague Dawley Rats in 104-Week Carcinogenicity Studies.

Microscopic observation data collected from approximately 1800 male and female Sprague Dawley (SD) control rats used on 104-week carcinogenicity studies performed at North American Labcorp Early Development, Inc, Madison, WI, were retrospectively evaluated for spontaneous nonneoplastic findings. This study provides incidence of the most common spontaneous nonneoplastic microscopic findings in each organ system of SD rats encountered during 104-week carcinogenicity studies. Some of the most common spontaneous background findings were cardiomyopathy; chronic progressive nephropathy; uterine cystic endometrial hyperplasia; prostate inflammation; pulmonary alveolar macrophage infiltrates; hepatocyte vacuolation, bile duct hyperplasia, and basophilic foci in the liver; pancreatic fibrosis; splenic extramedullary hematopoiesis and pigment; decreased lymphocytes and epithelial hyperplasia in the thymus; ventral brain compression; cystic degeneration and hyperplasia of the adrenal cortex; and mammary gland hyperplasia. The most common nonneoplastic findings in male SD rats were chronic progressive nephropathy (80.9%) and rodent progressive cardiomyopathy (73.2%). The most common nonnenoplastic findings in female SD rats were cystic degeneration of the adrenal cortex (64.7%) and ventral compression of the brain due to pituitary neoplasms (62.7%).

A novel classification and management scheme for craniocervical junction disorders with ventral neural element compression.

Craniocervical junction (CCJ) pathologies with ventral neural element compression are poorly understood, and appropriate management requires accurate understanding, description, and a more uniform nomenclature. The aim of this study was to evaluate patients to identify anatomical clusters and better classify CCJ disorders with ventral compression and guide treatment. A retrospective review of adult and pediatric patients with ventral CCJ compression from 2008 to 2022 at a single center was performed. The incidence of anatomical abnormalities and compressive etiologies was assessed. Surgical approach, radiographic data, and outcomes were recorded. Association rules analysis (ARA) was used to assess variable clustering. Among 51 patients, the main causes of compression were either purely bony (retroflexed dens [n = 18]; basilar invagination [BI; n = 13]) or soft tissue (degenerative pannus [n = 16]; inflammatory pannus [n = 2]). The primary cluster in ARA was a retroflexed dens, platybasia, and Chiari malformation (CM), and the secondary cluster was BI, C1-2 subluxation, and reducibility. These, along with degenerative pannus, formed the three major classes. In assessing the optimal treatment strategy, reducibility was evaluated. Of the BI cases, 12 of the 13 patients had anterolisthesis of C1 that was potentially reducible, compared with 2 of the 18 patients with a retroflexed dens (both with concomitant BI), and no pannus cases. The mean C1-2 facet angle was significantly higher in BI at 32.4°, compared with -2.3° in retroflexed dens and 8.1° in degenerative pannus (p < 0.05). Endonasal decompression with posterior fixation was performed in 48 (94.0%) of the 51 patients, whereas posterior reduction/fixation alone was performed in 3 patients (6.0%). Of 16 reducible cases, open posterior reduction alone was successful in 3 (60.0%) of 5 cases, with all successes containing isolated BI. Reduction was not attempted if vertebral anatomy was unfavorable (n = 9) or the C1 lateral mass was absent (n = 5). The mean follow-up was 28 months. Symptoms improved in 88.9% of patients and were stable in the remaining 11.1%. Tracheostomy and percutaneous G-tube placement occurred in 7.8% and 11.8% of patients, respectively. Reoperation for an endonasal CSF leak repair or posterior cervical wound revision both occurred in 3.9% of patients. In classifying, one cluster caused decreased posterior fossa volume due to an anatomical triad of retroflexed dens, platybasia, and CM. The second cluster caused pannus formation due to degenerative hypertrophy. For both, endonasal decompression with posterior fixation was ideal. The third group contained C1 anterolisthesis characterized by a steep C1-2 facet angle causing reducible BI. Posterior reduction/fixation is the first-line treatment when anatomically feasible or endonasal decompression with in situ posterior fixation when anatomical constraints exist.

Database Review of 514 Patients with Os Odontoideum. Detailed Analysis of 258 Surgically Treated (1978-2019).

Database review (1978-2019) is to identify the cause of os odontoideum, its presentation, associated abnormalities, and management recommendations. Review of referral database of 514 patients and 258 surgically treated patients ages 4-64years. Detailed history of early childhood trauma and initial encounter record retrieval were made. Patients had dynamic motion radiographs, dynamic motion MRI and also CT to identify pathology and reducibility of craniocervical instability. Preoperative crown halo traction was made before the year 2000 except in children. Intraoperative traction with O-arm/CT documentation was made since 2001. Reducible and partially reducible cases underwent halo traction under general anesthesia distraction, dorsal stabilization, and rib graft augmentation for fusion. Later semi-rigid instrumentation and subsequently rigid instrumentation was made. Irreducible compression of cervicomedullary junction was treated with ventral decompression. The follow up was 3-20years. Database; acute worsening after trauma 262, insidious neurological deficit 252. Minimal/normal motion with neurological deficit was present in 18, previous C1-C2 fusion with worsening in 18. 28 patients of 64 without treatment worsened in 4years. An intact odontoid process was seen in 52 children of 156 who had early craniovertebral junction trauma and later developed os odontoideum. There were 174 patients with reducible lesions and partially reducible were 22. Irreducible lesions were 62. Of the reducible, 50 underwent transarticular C1-C2 fusion, 26 C1 lateral mass, and C2 pars screw fixation. 182 had occipitocervical fusion (19 had extension of previous C1-C2 fusion and 43 after transoral decompression). 62 with irreducible ventral compression of the cervicomedullary junction underwent transoral decompression; 43 had a trapped transverse ligament between the os and C2 body and 19 previous C1-C2 fusions. Compression was by the axis body, os odontoideum, and the posterior C2 arch. Syndromic and skeletal/connective tissue abnormalities were found in 86 (36%). 2 patients worsened, age 10 and 62, due to failure of semi-rigid construct. The etiology of os odontoideum is multifactorial considering the associated abnormalities, reports of congenital-familiar occurrence, and early childhood craniovertebral trauma which also plays a role in the etiology. Patients with reducible lesions require stabilization. Asymptomatic patients are at risk for later instability. Patients who underwent childhood C1-C2 fusion must be followed for later problems. The irreducibility was seen due to trapped transverse ligament, pannus, or previous dorsal C1-C2 fusion.

Case report: Recurrent cervical spinal stenosis masquerading as myalgic encephalomyelitis/chronic fatigue syndrome with orthostatic intolerance

IntroductionMyalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex, chronic, multi-system disorder that is characterized by a substantial impairment in the activities that were well tolerated before the illness. In an earlier report, we had described three adult women who met criteria for ME/CFS and orthostatic intolerance, and had congenital or acquired cervical spinal stenosis. All three experienced substantial global improvements in their ME/CFS and orthostatic intolerance symptoms after recognition and surgical treatment of the cervical stenosis. After a several year period of improvement, one of the individuals in that series experienced a return of ME/CFS and orthostatic intolerance symptoms.Main symptoms and clinical findingsRadiologic investigation confirmed a recurrence of the ventral compression of the spinal cord due to a shift of the disc replacement implant at the involved cervical spinal level.Therapeutic interventionDecompression of the spinal cord with removal of the implant and fusion at the original C5-C6 level was once again followed by a similar degree of improvement in function as had been observed after the first operation.ConclusionThis recapitulation of the outcomes after surgical management of cervical stenosis provides further evidence in support of the hypothesis that cervical spinal stenosis can exacerbate pre-existing or cause new orthostatic intolerance and ME/CFS. Especially for those with refractory symptoms and neurological signs, surgical interventions may offer relief for selected patients with this complex condition.

A new species of possible archipolypodan millipedefrom the Carboniferous of the Netherlandswith unusually long tergites

Millipedes have a long evolutionary history, with the oldest presumed fossils of Diplopoda de Blainville in Gervais, 1844 being from the Silurian and the first definite fossil record originating from Devonian deposits. The phylogeny of Diplopoda is not fully resolved yet, especially not concerning fossil representatives. At the same time, already in the Palaeozoic millipedes showed quite a morphological and presumably also ecological variety. We describe here a new species of a Carboniferous millipede from the Westphalian A of the Netherlands, Lauravolsella willemeni n. gen., n. sp., a possible representative of Archipolypoda (†Archipolypoda Scudder, 1882). The species is based on a single specimen, preserved with part and counterpart, which both show a three-dimensional preservation. The specimen has unusually long tergites, in normal life position covering most of the following segment. These long tergites might have been beneficial when performing defensive enrolling. In extant millipedes, enrolling is usually facilitated by softer areas between the sternites, allowing for a certain degree of ventral compression. In the new fossil, the sclerotic sternites occupy the entire length of the ventral side of the segment, not allowing for any type of compression. The new fossil therefore demonstrates another solution for the mechanical challenges during enrolment and increases the morphological diversity of Carboniferous millipedes.

Endoscopic odontoidectomy for brainstem compression in association with posterior fossa decompression and occipitocervical fusion.

Endonasal endoscopic odontoidectomy (EEO) is an alternative to transoral surgery for symptomatic ventral compression of the anterior cervicomedullary junction (CMJ), allowing for earlier extubation and feeding. Because the procedure destabilizes the C1-2 ligamentous complex, posterior cervical fusion is often performed concomitantly. The authors' institutional experience was reviewed to describe the indications, outcomes, and complications in a large series of EEO surgical procedures in which EEO was combined with posterior decompression and fusion. A consecutive, prospective series of patients who underwent EEO between 2011 and 2021 was studied. Demographic and outcome metrics, radiographic parameters, extent of ventral compression, extent of dens removal, and increase in CSF space ventral to the brainstem were measured on the preoperative and postoperative scans (first and most recent scans). Forty-two patients (26.2% pediatric) underwent EEO: 78.6% had basilar invagination, and 76.2% had Chiari type I malformation. The mean ± SD age was 33.6 ± 3.0 years, with a mean follow-up of 32.3 ± 4.0 months. The majority of patients (95.2%) underwent posterior decompression and fusion immediately before EEO. Two patients underwent prior fusion. There were 7 intraoperative CSF leaks but no postoperative CSF leaks. The inferior limit of decompression fell between the nasoaxial and rhinopalatine lines. The mean ± SD vertical height of dens resection was 11.98 ± 0.45 mm, equivalent to a mean ± SD resection of 74.18% ± 2.56%. The mean increase in ventral CSF space immediately postoperatively was 1.68 ± 0.17 mm (p < 0.0001), which increased to 2.75 ± 0.23 mm (p < 0.0001) at the most recent follow-up (p < 0.0001). The median (range) length of stay was 5 (2-33) days. The median time to extubation was 0 (0-3) days. The median time to oral feeding (defined as, at minimum, toleration of a clear liquid diet) was 1 (0-3) day. Symptoms improved in 97.6% of patients. Complications were rare and mostly associated with the cervical fusion portion of the combined surgical procedures. EEO is safe and effective for achieving anterior CMJ decompression and is often accompanied by posterior cervical stabilization. Ventral decompression improves over time. EEO should be considered for patients with appropriate indications.

Transtubular Transoral Approach for Irreducible Ventral Craniovertebral Junction Compressive Pathologies: Surgical Technique and Outcome.

To investigate the use of a tubular retractor to provide access to the craniovertebral junction (CVJ) sparing the soft palate with the aim of reducing complications associated with traditional transoral approach but yet allowing adequate decompression of the CVJ. Twelve consecutive patients with severe myelopathy (JOA-score less than 11) from ventral CVJ compression were operated between 2014-2020 using a tubular retractor assisted transoral decompression. All patients improved neurologically statistically (p=0.02). There were no posterior pharynx wound infections or rhinolalia. There was one case with incomplete removal of the lateral wall of odontoid and one incidental durotomy. A Tubular retractor provides adequate access for decompression of the ventral compression of CVJ. As the tubular retractor pushed away the uvula, soft palate and pillars of the tonsils as it docked on the posterior pharyngeal wall, the traditional complications associated with traditional transoral procedures is completely avoided.

A New Proximal Adjustable Sling ATOMS SSP® Implantation Technique with Focus on the Urethral Bulb: Lessons Learned from Revision Surgery.

Adjustable sling ATOMS-SSP results in ventral compression of the urethra with favorable results in the treatment of men with mild to moderate stress incontinence. However, with transobturator tunneling and mesh fixation, the surgeon has a range of options, which leads to different results and sometimes unfavorable positioning of the silicone cushion. Using retrograde urethrography (RUG), we identified ATOMS patients with considerable misplacement. We then modified the implantation technique when we performed the revision, and now present here our first experiences with this new surgical technique. Patients after ATOMS-SSP implantation at our clinic were systematically subjected to a RUG if incontinence persisted after adjustments. In case of unfavorable positioning, a revision was performed with the aim of achieving an idealized urethroproximal position of the silicone pad. During follow-up, a repeat RUG was performed, and both subjective and objective outcome parameters were recorded. Four men met the above criteria and underwent revision with reimplantation using our new technique. All patients postoperatively experienced significantly improved continence. RUGs demonstrated an ideal ATOMS position immediately below the proximal bulbar urethra. Our proximal implantation technique, presented here for the first time, allows optimal positioning of the ATOMS SSP, which is reflected in the objective parameters and RUG. Its use in primary implantation should also be considered and an expansion to the indication of severe stress incontinence seems possible, but this should only be done in studies.

Effect of modified clivoaxial angle on surgical decision making and treatment outcomes in patients with Chiari malformation type 1.

Chiari malformation type 1 (CM1), a complex pathological developmental disorder of the craniovertebral junction, is typically characterized by herniation of the cerebellar tonsils from the foramen magnum. Treatment using posterior fossa decompression alone without taking the ventral cervico-medullary compression into consideration may lead to unsatisfactory treatment outcomes. The current study evaluated the utility of the modified clivoaxial angle (MCAA) in assessing ventral compression and also examined its effect on treatment outcomes. This retrospective study included 215 adult patients who underwent surgical treatment for CM1 at one medical center over a 10-year period. The following surgical techniques were used to decompress the posterior fossa: (a) PFD: bone removal only; (b) PFDwD: bone removal with duraplasty; and (c) CTR: cerebellar tonsil resection. The morphometric measurements of the craniovertebral junction (including MCAA) were recorded using preoperative images, and the postoperative clinical status was evaluated using the Chicago Chiari outcome scale (CCOS). MCAA was positively correlated with the CCOS score and also independently predicted treatment outcome. To enable Receiver operating characteristic (ROC) curve analysis of CCOS scores, the patients were divided into three groups based on the MCAA cut-off values, as follows: (a) severe (n = 43): MCAA ≤ 126; (b) moderate (n = 86): 126 < MCAA ≤ 138; and (c) mild (n = 86): MCAA > 138. Group a exhibited severe ventral cervico-medullary compression (VCMC), and their CCOS scores for the PFD, PFDwD, and CTR groups were 11.01 ± 1.2, 11.24 ± 1.3, and 13.01 ± 1.2, respectively (p < 0.05). The CCOS scores increased with widening of the MCAA angle in all surgical groups (p < 0.05). Furthermore, patients with mild MCAA (>138°) exhibited 78% regression of syringomyelia, and this was significantly greater than that observed in the other groups. MCAA can be used in the selection of appropriate surgical techniques and prediction of treatment outcomes, highlighting the importance of preoperative evaluation of ventral clivoaxial compression in patients with CM1.

Surgery for basilar invagination with and without Chiari I malformation.

The surgical treatment for Chiari I malformation and basilar invagination has been discussed with great controversy in recent years. This paper presents a treatment algorithm for these disorders based on radiological features, intraoperative findings, and analyses of long-term outcomes. Eight-five operations for 82 patients (mean ± SD age 40 ± 18 years; range 9-75 years) with basilar invagination were evaluated, with a mean follow-up of 57 ± 55 months. Apart from the radiological features and intraoperative findings, findings on neurological examinations before and after surgery were analyzed. Long-term outcomes were evaluated with Kaplan-Meier statistics. All 77 patients with a Chiari I malformation underwent foramen magnum decompression with arachnoid dissection and duraplasty. Patients with ventral compression by the odontoid peg were managed with posterior realignment and C1-2 fusion. Patients without ventral compression did not undergo C1-2 fusion unless radiological or clinical signs of instability were detected. Thirty-three patients without ventral compression or instability underwent foramen magnum decompression without additional fusion, whereas 52 operations on 49 patients involved posterior fusion at C0-2 or C1-2 after realignment of ventral compression and/or treatment of C1-2 instability. Postoperatively, gait ataxia, swallowing functions, and suboccipital pain improved significantly in both treatment groups. In total, 79% and 73% of patients reported that their condition improved after foramen magnum decompression alone and after fusion with or without foramen magnum decompression, respectively. Progression-free survival rates at 10 years were 83% and 81%, respectively. Among the patients with basilar invagination, a subgroup consisting of 40.2% of the included patients underwent successful long-term treatment with foramen magnum decompression alone and without additional fusion. This subgroup was characterized by the absence of a ventral compression and no atlantoaxial dislocation or other signs of craniocervical instability. The remainder of patients underwent C1-2 fusion with posterior realignment of ventral compression if required. In the presence of basilar invagination, Chiari I malformation should be treated with foramen magnum decompression and duraplasty.

A Novel Craniocervical Junction Compression Severity Index-Based Grading System for Multidirectional Quantification of the Biomechanics at Foramen Magnum of Chiari Malformation Type I.

Objective This study aimed to establish a novel grading system, based on the craniovertebral junction compression severity index (CVJCSI) for multidirectional quantification at the foramen magnum plane for Chiari malformation type I (CMI). Methods The CVJCSI grading system was established to stratify patients based on the ventral (modified clivoaxial angle < 138°), dorsal (tonsil herniation), and central (brainstem herniation) CVJ (craniovertebral junction) compression, the CVJCSI grading system was established to stratify patients. The optimal surgical method for each grade was recommended by intragroup comparisons regarding the efficacy of the three operations. Finally, according to the CVJCSI grading system, a prospective validation trial was performed and surgically treated for internal validation. Results Based on the retrospective study ( n = 310), the CVJCSI included six grades: I: syrinx alone without compression; II: dorsal compression; III: dorsal and central compression; IV: ventral compression; V: dorsal and ventral compression; and VI: ventral, dorsal, and central compression. Among all available variables, only the CVJCSI and surgical methods significantly affected the CCOS. The CCOS scores, overall and for each CVJCSI grade, increased in the prospective cohort ( n = 42) compared with that in the retrospective analysis. Conclusions The CVJCSI can be used to stratify CMI patients. The higher the CVJCSI grade, the more severe the CVJ compression and the worse posterior fossa deformity. Meanwhile, the CVJCSI was negatively correlated with the CCOS. The lower the CVJCSI grade, the better the response to surgery, and the less-invasive surgical procedures were warranted. Finally, the prospective cohort study validated the proposed CVJCSI-based surgical protocols.

Anterior Cervical Controllable Antedisplacement and Fusion (ACAF): Improving Outcomes for Severe Cervical Ossification of the Posterior Longitudinal Ligament.

The detailed steps to perform ACAF have been described previously1. Briefly, following induction of general endotracheal anesthesia, a standard right- or left-sided Smith-Robinson incision is made. Discectomies are performed at the involved levels. By measuring the thickness of the OPLL on an axial preoperative computed tomography scan at each compressed level, the amount of each anterior vertebral body to be resected can be calculated preoperatively. This was, in general, equal to the thickness of the ossified mass at the same level. The previously calculated portion of each involved body in the vertebral body-OPLL complex is resected. Following the creation of a contralateral longitudinal osseous trough, the prebent anterior cervical plate is then placed, and the screws are installed after proper drilling and taping on the remaining vertebral bodies. The screws utilized in this procedure should not be too short to achieve adequate purchase in the vertebral body. Subsequently, the intervertebral cages are inserted. Thus, the vertebral body-OPLL complex is temporarily stabilized for the next procedure. Next, an ipsilateral longitudinal osseous trough is created to completely isolate the vertebral body-OPLL complex. Notably, the objective of complete isolation of the vertebral body-OPLL complex is to further anteriorly hoist the complex to decompress the spinal cord. Finally, screws are inserted through the plate and into each vertebral body and are gradually tightened to displace the bodies anteriorly. Allogenic iliac bone graft is placed in the longitudinal bone troughs to promote fusion. Nonoperative treatment is frequently ineffective. Traditional surgical interventions have included anterior cervical corpectomy and fusion (ACCF), posterior laminoplasty, and laminectomy2,3. ACCF focuses on resecting the ventral ossified mass in order to obtain direct decompression; however, this technique is very technically demanding, with a high risk of complications. In addition, the clinical benefits of ACCF will be limited when the OPLL extends over >3 levels. Posterior decompression can achieve indirect decompression by allowing the spinal cord to float away from the ossified mass. This technique depends largely on the preoperative presence of cervical lordosis and is contraindicated in patients with kyphosis or severe OPLL. In addition, posterior decompression surgery has been associated with a high incidence of late neurological deterioration and even revision surgery2. ACAF combines the advantages of direct decompression as occurs with ACCF with the limited manipulation of the canal contents as occurs with the posterior approach4-6. The procedure considers the ossified mass and the vertebral body as a single unit. Decompression is accomplished by moving the vertebral body with the OPLL ventrally away from the spinal cord. The preserved part of the vertebral body-OPLL complex becomes part of the anterior wall of the spinal canal. Without direct instrument manipulation inside the canal, the occurrence of cerebrospinal fluid leakage, hemorrhage, and intraoperative neural injury can be minimized5. Compared with a posterior approach, ACAF can achieve more decompression of the cord, especially in patients with cervical kyphosis and those with >60% of the spinal canal occluded6. This procedure can yield satisfactory clinical outcomes with fewer surgery-related complications1,4-6,9. A single-center, prospective, randomized controlled study showed significantly better Japanese Orthopaedic Association scores and recovery rates at 1 year for ACAF compared with laminoplasty for the treatment of multilevel OPLL in cases in which the occupying ratio of the canal was >60% occluded or the K-line (i.e., a virtual line between the midpoints of the anteroposterior canal diameter at C2 and C7) was negative9. In addition, patients who underwent ACAF had better preservation of cervical lordosis and sagittal balance9. The cervical segments to be treated should include all of the segments with OPLL that are causing spinal cord compression.The uncinate process can be utilized as a safe anatomical landmark for the longitudinal osteotomies in order to avoid vertebral artery injury, even in cases with severely ossified masses.Careful evaluation of the vertebral artery on preoperative magnetic resonance imaging or computed tomography is of great importance.Appropriately increasing the curvature of the cervical plate can further enlarge the space for the following antedisplacement of the vertebral body-OPLL complex.The location of the uncinate processes must be confirmed before the creation of the 2 longitudinal osseous troughs7,8.The preserved superior and inferior vertebral end plates should be made as smooth and mutually parallel as possible.The thickness of the anterior part of the vertebral bodies to be resected should be calculated preoperatively.The posterior longitudinal ligament behind the involved segments should not be resected. ACAF = anterior cervical controllable antedisplacement and fusionACCF = anterior cervical corpectomy and fusionOPLL = ossification of the posterior longitudinal ligamentCT = computed tomographyJOA = Japanese Orthopaedic AssociationMRI = magnetic resonance imagingOR = occupying rate of the spinal canalVOC = vertebral bodies-OPLL complexRR = recovery rateCSF = cerebrospinal fluidUP = uncinate processTF = transverse foramen.

Review of transoral odontoidectomy. Where do we stand? Technical note and a single-center experience

BackgroundTransoral odontoidectomy followed by occipitocervical fixation is an accepted technique for the treatment of ventral compression at the craniocervical junction (CVJ). It is thought that surgical experience has stagnated owing to both the development of endonasal approaches, and improvement in rheumatoid pharmaceutical therapies. Accurate knowledge on whether the declining experience affects rates of intra-operative and peri-operative complications is essential. Herein, we present an illustrated technical note and case series based on our 10-year surgical experience. MethodsTechnical pearls for the transoral ondontoidectomy approach are discussed and illustrated. A retrospective analysis of patients aged 18 years or older who underwent the procedure over the last 10 years was conducted. Both intra and post-operative complications were recorded and compared to historical controls. ResultsTen patients were identified with an average of 60 years of age and follow-up time of 15 months. Indications for surgery included rheumatoid (10%), degenerative (30%) and pseudogout cervical pannus (10%), basilar invagination (30%), and malignancy (20%). Average length of stay was 19.4 days. Two patients suffered from intra-operative CSF leaks while 8 patients suffered from post-operative medical complications including the need for tracheostomy for 4 individuals. Rate of improved neurological outcomes was 60% while 20% of patients were stable at last clinic follow-up. ConclusionIn this study, we describe our technique to obtain exposure and perform decompression of CVJ ventral pathologies via the transoral route. The intra and post-operative complications we report represent the common pitfalls. Highly specialized and comprehensive patient care remains essential as post-operative complication rates remain high.

Determination of cutoff values on computed tomography and magnetic resonance images for the diagnosis of atlantoaxial instability in small-breed dogs.

ObjectiveTo determine cutoff values for the diagnosis of atlantoaxial instability (AAI) based on cross‐sectional imaging in small‐breed dogs.Study designRetrospective multicenter study.Sample populationClient‐owned dogs (n = 123) and 28 cadavers.MethodsDogs were assigned to three groups: a control group, a “potentially unstable” group, and an AAI‐affected group, according to imaging findings and clinical signs. The ventral compression index (VCI), cranial translation ratio (CTR), C1‐C2 overlap, C1‐C2 angle, atlantoaxial distance, basion‐dens interval, dens‐to‐axis length ratio (DALR), power ratio, and clivus canal angles were measured on CT or T2‐weighted magnetic resonance (MR) images. Receiver operating characteristic (ROC) analysis was performed to define cutoff values in flexed (≥25°) and extended (<25°) head positions.ResultsCutoff values for the VCI of ≥0.16 in extended and ≥0.2 in flexed head positions were diagnostic for AAI (sensitivity of 100% and 100%, specificity of 94.54% and 96.67%, respectively). Cutoff values for the other measurements were defined with a lower sensitivity (75%‐96%) and specificity (70%‐97%). A combination of the measurements did not increase the sensitivity and specificity compared with the VCI as single measurement.ConclusionCutoff values for several imaging measurements were established with good sensitivity and specificity. The VCI, defined as the ratio between the ventral and dorsal atlantodental interval, had the highest sensitivity and specificity in both head positions.Clinical significanceThe use of defined cutoff values allows an objective diagnosis of AAI in small‐breed dogs. The decision for surgical intervention, however, should remain based on a combination of clinical and imaging findings.

Relevance of C1/2 Facet Configurations and Clivus-Canal-Angles for Adult Patients with Chiari I Malformation with and without Basilar Invagination

C1/2 facet configurations and clivus-canal-angles (CXAs) have been proposed as criteria for posterior fusion in Chiari I malformation (CMI). Three-hundred and forty adults with CMI without basilar invagination (BI), 111 with CMI with BI, and 100 age- and sex-matched controls were studied using sagittal T2-weighted magnetic resonance imaging scans analyzing preoperative and postoperative values with their impact on progression-free survival rates. For CMI without BI, C1/2 facet configurations and CXA were similar to controls (142 ± 11 degrees and 144 ± 10 degrees, respectively) with low rates for posterior C1 displacements (7.1% and 10%, respectively). In CMI with BI, C1 facet displacements were common (54.9%) with lower CXA (120 ± 15 degrees). After foramen magnum decompression (FMD) in CMI without BI (n= 169), 1.8% developed posterior C1 facet displacements without CXA changes and a 97% progression-free survival rate for 10 years. In CMI with BI, patients without ventral compression or instability underwent FMD without fusion (n= 19). Among them, 5.3% developed a posterior C1 facet displacement without CXA changes and a 94% progression-free survival rate for 10 years. The remainder of CMI with BI underwent FMD with C1/2 fusion (n= 48). Among these, CXA values increased with 10-year progression-free survival rates of 74% and 93% with and without ventral compression, respectively. For adult CMI without BI, C1/2 facet configurations and CXA are irrelevant. FMD alone provides excellent long-term outcomes. In CMI with BI, anterior C1 facet displacements indicate C1/2 instability. Posterior fusions can be reserved for patients with ventral compression or C1/2 instability.

Characteristic computed tomographic myelography findings in 23 Thoroughbred horses.

The purpose of this observational study was to determine the characteristic computed tomographic (CT) myelography findings of cervical vertebral stenotic myelopathy (CVSM) lesions in Thoroughbred horses. A total of 23 Thoroughbred horses (age range, 155–717 days on CT examination; mean, 410.9 days) were analyzed. All 23 Thoroughbred horses underwent unenhanced radiography, radiographic myelography, and CT myelography. Unenhanced radiographs were observed the presence of cervical vertebral malalignment and osseous lesions. Radiographic myelograms were observed for signs of cervical spinal cord compression; additionally, CT myelograms were used to detect cervical vertebral osseous lesions. Ventral compressions were frequently observed in the cranial cervical vertebrae (C2–C4), whereas dorsal compressions were frequently observed in the caudal cervical vertebrae (C5–C7). Furthermore, osseous lesions of the caudal articular process developed more frequently than those of the cranial articular process. CT myelography in Thoroughbred horses is a useful method for detecting CVSM changes.

Posterior midline approach to odontoidectomy: A novel method to treat basilar invagination.

ABSTRACTBackground:Basilar invagination (BI) is a common malformation of the craniocervical region where the odontoid process protrudes into the foramen magnum. Surgery in this region is difficult because of the complex anatomy of the craniocervical junction. Serious life-threatening complications have been observed with previously described approaches. Therefore, we conceived a novel surgical approach that can be implemented by neurosurgeons with different skill levels to facilitate better outcomes.Methods:We describe a new surgical technique for the treatment of BI that we used in two patients in whom cervical myelopathy and direct ventral compression of the cervicomedullary junction were confirmed through clinical and radiological findings. We present the technique of posterior odontoidectomy in a step-by-step, didactic, and practical manner with surgical tips and tricks.Results:The resection was completed without intraoperative or postoperative complications in both cases. The patients experienced substantial neurological improvements, and full recovery was observed during the 9-month and 12-month follow-up visits after discharge. Compared with the transoral approach, our technique provides a larger decompression area.Conclusions:We describe a novel method for the treatment of BI that was applied in two patients and suggest that the posterior approach might be a safe and effective method for ventral decompression of the craniocervical junction. Posterior odontoidectomy followed by craniocervical fixation helped achieve complete cervicomedullary decompression.

Розробка і перевірка вірогідності методу оцінювання вентральної компресії хребетного каналу при хребетно-спинномозковій травмі

Актуальність. Механічна компресія вмісту хребетного каналу, що виникає при травматичному пошкодженні хребта, має основоположне значення при визначенні тактики терапії і прогнозів регресу неврологічних розладів у постраждалих. Аналіз даних літератури демонструє відсутність критерію, який дозволяє характеризувати морфологічно гетерогенний субстрат, що викликає компресію спинного мозку. Мета: сформулювати визначення, розробити і виконати перевірку вірогідності рентгенограмметричного методу оцінки сагітального розміру різних за морфологічним типом вентрально-інтраканально розташованих травматичних субстратів. Матеріали та методи. Інформаційний пошук дозволив виявити існуючі індекси і методи вимірювання ступеня компресії хребетного каналу, а також клінічну значимість характеру і ступеня компресії спинного мозку травматичним субстратом. Для первинної перевірки вірогідності методу оцінювання вентрально розташованого травматичного субстрату був проведений ретроспективний аналіз даних нейровізуалізації 150 пацієнтів із травматичними змінами шийного відділу хребта. Були проаналізовані дані спондилограм, комп’ютерних та магнітно-резонансних томограм. Вимірювання проводились трьома незалежними експертами. Результати. Розроблений термін «компримуючий фактор», що становить собою збірне поняття і відображає загальну характеристику патологічних анатомічних субстратів, які виникають при ушкодженнях хребетного рухового сегмента, що призводять до деформації стінок хребетного каналу і, як наслідок, викликають здавлення структур хребетного каналу. Для кількісної характеристики виконувалось вимірювання сагітального розміру компримуючого фактора, що має абсолютну метричну величину і характеризує відносний ступінь зміщення субстрату в просвіт хребетного каналу. Отримані при статистичній обробці результати виявляють високу відтворюваність результатів вимірювань. Коефіцієнт конкордації становив 0,85 при р = 0,00025. Висновки. Наведену радіологічну ознаку доцільно використовувати для загальної характеристики клінічного випадку, а також при статистичній обробці даних із метою уніфікації уявлення про ступінь компресії вмісту хребетного каналу.

Influence of the Head Neck Position on Imaging Measurements Used to Assess the Craniovertebral Junction in Small Breed Dogs: A Cadaveric Study.

The study aimed to determine the influence of head neck position on imaging measurements used to assess the craniovertebral junction (CVJ) and to recommend the most appropriate position for the evaluation of the CVJ. A cross-sectional sample of adult dogs' cadavers was subjected to a computed tomography scan of the cranium and the cranial cervical region in three standardized head positions. Imaging measurements often used to assess the CVJ were measured. The influence of the head neck position, breed, weight and gender on imaging measurements was tested using repeated measures analysis of variance. Twenty-eight cadavers of small breed dogs were enrolled in the study. All cadavers examined had occipital dysplasia. All transarticular imaging measurements were dependent on the head neck position. In addition, the breed, weight and gender had an influence on several measurements. We recommend a standardized head neck position of 50 degrees flexion if quantitative imaging measurements of the CVJ are used to diagnose pathologies in this region. Future studies should focus on the definition of cut-off values for quantitative imaging measurements of the CVJ to differentiate between healthy and diseased small breed dogs. Regarding atlantoaxial instability, a combination of six parameters (C1-C2 angle, C1-C2 overlap, atlantoaxial distance, dens-to-axis length ratio, ventral compression index and clivus canal angle) is promising for its diagnosis.

Compression of the сeliac trunk syndrome. History of the problem

The article presents the main stages of the development of ideas about a fairly rare pathology in clinical practice the syndrome of compression of the ventral trunk. Until the mid-nineteenth century, reports of the clinical picture of chronic abdominal ischemia were more descriptive. Serial pathoanatomic studies, comparison of anatomical features revealed at autopsy with clinical manifestations accompanying these changes, contributed to the isolation of chronic ischemic disease of the digestive system in a separate nosological form. The discovery of angiography contributed to the significant development of vascular surgery and the isolation of the ventral trunk compression syndrome as an independent disease, since it allowed for a lifetime comparison of the detected changes in blood vessels with the clinical manifestations of the disease. The term ventral trunk compression syndrome was first introduced by P. Harjola when describing a case of abdominal pain in a patient with compression of the ventral trunk by the neuroganglionic tissue of the ventral plexus. Later, J. Dunbar confirmed the Association of clinical manifestations of chronic abdominal pain with compression of the ventral trunk by the median arched ligament of the diaphragm. In English-language literature, the disease was named Dunbar syndrome. The effectiveness of eliminating the symptoms of this disease by surgical dissection of compression structures has been proven. Further study of this problem developed in parallel with the development of surgery in General in accordance with the emergence and introduction of new surgical technologies. The purpose of numerous studies was to study the etiopathogenetic mechanisms of the occurrence of a variety of clinical manifestations of this syndrome and improve the results of its treatment by improving known surgical techniques and introducing new ones.