Sacral Segments Research Articles

Biotinylated dextran amine anterograde tracing of the canine corticospinal tract.

In this study, biotinylated dextran amine (BDA) was microinjected into the left cortical motor area of the canine brain. Fluorescence microscopy results showed that a large amount of BDA-labeled pyramidal cells were visible in the left cortical motor area after injection. In the left medulla oblongata, the BDA-labeled corticospinal tract was evenly distributed, with green fluorescence that had a clear boundary with the surrounding tissue. The BDA-positive corticospinal tract entered into the right lateral funiculus of the spinal cord and descended into the posterior part of the right lateral funiculus, close to the posterior horn, from cervical to sacral segments. There was a small amount of green fluorescence in the sacral segment. The distribution of BDA labeling in the canine central nervous system was consistent with the course of the corticospinal tract. Fluorescence labeling for BDA gradually diminished with time after injection. Our findings indicate that the BDA anterograde tracing technique can be used to visualize the localization and trajectory of the corticospinal tract in the canine central nervous system.

Application of epidural electrostimulation to treat bladder dysfunction in patients with consequences of traumatic injury of lumbar and sacral segments of the spinal cord

Background. Bladder dysfunction is one of the most frequent and severe clinical manifestations of traumatic disease of the spinal cord, which causes chronic inflammatory processes in the urinary tract and impairs the quality of life of a patient.Methods. The results of correction of bladder dysfunction after epidural electrostimulation in 69 patients with consequences of spinal cord injury of lumbar and sacral segments of the spinal cord are presented. The degree of urination control was evaluated (none, partial, complete) before and after applied treatment.Results: in group A partial urination control was achieved in 45% of patients, in group B — in 61.5%, in 1 (7.7%) patient bladder control function restored completely. In group C a positive result in restoration of bladder function was achieved in 89.6% of patients, in group D — in all patients. It was incontinentia vera, at which we achieved best results of correction, 90.5% of patients showed positive results.Conclusions. Epidural electrostimulation is an effective method of correction of bladder dysfunction in patients with consequences of traumatic injury of spinal cord lumbar and sacral segments.

Can Lumbopelvic Fixation Salvage Unstable Complex Sacral Fractures?

Traditional screw or plate fixation options can be used to fix the majority of sacral fractures. However, these techniques are unreliable with dysmorphic upper sacral segments, U-fractures, osseous compression of neural elements, and previously failed fixation. Lumbopelvic fixation can potentially address these injuries but is a technically demanding procedure requiring spinal and pelvic fixation and it is unclear whether it reliably corrects the deformity and restores function. We therefore assessed reduction quality and loss of fixation, pain related to prominent hardware, subjective dysfunction measured by the Short Musculoskeletal Function Assessment (SMFA), and complications. We retrospectively reviewed 15 patients with unstable sacral fractures treated with lumbopelvic fixation between 2002 and 2010. Patients had radiographic monitoring regarding reduction quality and loss of fixation and clinical followup using the SMFA. The minimum followup was 12 months (mean, 23 months; range, 12-41 months). Posterior reduction quality was 11 of 15 with less than 5 mm persistent displacement and four of 15 with 5 to 10 mm displacement. Loss of fixation was observed in one patient as a result of a technical error. Prominent hardware resulted in greater pain. Despite daily activity and bother subscores improving over time, we found long-term dysfunction in the SMFA. Eleven of the 15 patients were able to return to previous work or activities. Complex posterior pelvic ring injuries of the sacrum not amenable to traditional fixation options can be salvaged with adherence to the technical details of lumbopelvic fixation. Hardware prominence and pain are markedly reduced with screw head recession. Long-term impairment is noted in patients with complex pelvic ring injuries requiring lumbopelvic fixation compared with normative data. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Partial pedicle subtraction osteotomy (PPSO): A modification for PSO in treatment of sagittal deformities.

Background data: Pedicle subtraction osteotomy is used for treatment of sagittal deformities. It has the advantages of being accomplished completely through a posterior approach. Neurological deficits that accompany the procedure are believed to be the result of a combination of subluxation, residual dorsal impingement, and dural buckling.Purpose: To introduce a new modification of the traditional pedicle subtraction osteotomy, in which we perform partial pedicle osteotomy; preserving the inferior third of the pedicle. This allows more smooth correction of the deformity,minimizes the injury or irritation of the nerve root below this pedicle, and decreases the incidence of subluxation and dorsal impingement. Since the correction occurs with theoretically smaller wedges, better closure and union of the osteotomy site is expected. Study design: Our retrospective study included 33 patients with sagittal plandeformity (16 cases of ankylosing spondylitis, 8 cases of old fractures, 5 cases of congenital kyphosis and 4 cases of postlaminectomy kyphosis after cord tumour resection). Methods: All patients were treated by our modifications of the pedicle subtraction osteotomy technique. Radiographic analysis included assessment of kyphosis by regional Cobb angle, and the CV7 sagittal plumb line in pre and post plain radiographs. Clinically, the patients are assessed by the Oswestry functional score. Results: Our series included 23 male and 10 females. The age was of a mean 42.3 years. The vertical plumb line distance from the first sacral segment improved to 3.4 cm compared to a mean of 9.3 preoperatively. The degree of correction for single osteotomy was of a mean of 22.4°. The intervertebral foramen below theosteotomised pedicle showed unchanged vertical dimension after the osteotomy. The complications included 4 cases of dural tears, 1 case of massive bleeding (2500 ml), 3 cases of superficial wound infection, and 1 case developed transientpostoperative paraparesis. There was no single case of root injury. The follow-up of the patients was of mean 27.4 months. At the end of follow up, radiologically, there was a loss of correction of mean of 2 degrees with no case of pseudoarthrosis or metal failure. According to Oswestry disability score, 88% of patients were able to return to their normal to moderate daily activities with good self image and overall satisfaction. Conclusion: Although our new technique is technically demanding, it has lower rate of neurological complication with better chances of union than the traditionalosteotomy.

Lumbar lordosis and pars interarticularis fractures: a case–control study

The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9° (SD = 6.5°) in the pars interarticularis fracture group, and 30.1° (SD = 6.4°) in the control group. The difference between the two groups was significant (mean difference 6.8°, Student'st test: P < 0.001). The mean angle of sacral tilt measured was 122.2° (SD = 10.16°) for controls and 136.4° (SD = 10.86°) for patients with pars defects. The difference in the means of 14.2° was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis.

Persistent sacrococcygeus ventralis muscle in an adult human pelvic wall: A variation for surgeons to note

Occurrence of abnormal muscles in the pelvic wall is very rare. During a routine dissection of the pelvic wall, an abnormal muscle referred to as sacrococcygeus ventralis was noted in a 65-year-old South Indian cadaver. The fleshy fibers of the muscle were arising from the lateral part of the ventral surface of the sacrum at the level of S3 segment. The muscle passed downwards in front of the S4 and S5 sacral segments, halfway through its course it became tendinous and finally became inserted in the ventral surface of the coccyx. Sacrococcygeus ventralis is a muscle which is well developed in animals where it acts on their tail. In human beings, sacrococcygeus ventralis is seen only during fetal life. A rare case of its persistence in an adult pelvic wall is reported and discussed here.

Gurltia paralysans ( ): Description of adults and additional case reports of neurological diseases in three domestic cats from southern Chile

Adults of Gurltia paralysans were obtained from veins of the spinal cord subarachnoid space from three domestic cats presenting with chronic paraparesis/paraplegia from rural areas of southern Chile. Four adult nematodes were collected (2 males and 2 females) were recovered from cat 1, 14 adult nematodes (12 females and 2 males) from cat 2, and 12 nematodes (10 females and 2 males) were collected from cat 3. Parasite induced lesions that compromised subarachnoid vein microvasculature at the thoracic, lumbar, sacral spinal cord segments extending to conus medularis. Female nematodes measured 25mm long (range=25–30mm) and 0.1mm wide. Male measured a mean of 16mm length (range=13–18mm) with a body diameter of 0.1mm (range=0.08–0.15mm). The present study described structural features of G. paralysans, a rare parasite first reported in the 1930s, and provides additional reports on associated clinical and pathological findings in naturally infected domestic cats.

Changes in electrical perceptual threshold in the first 6 months following spinal cord injury

ObjectivesTo investigate the use of electrical perceptual threshold (EPT) testing to follow the natural history of sensory progression after complete and incomplete acute spinal cord injury (SCI) and to compare EPT changes with the American Spinal Injuries Association (ASIA) Impairment Scale (AIS).Study DesignProspective descriptive study.MethodsASIA examination and EPT testing was performed on 17 patients (7 AIS A, 10 AIS B–D), within 1, 3, and 6 months after acute SCI. EPT assessment was carried out bilaterally at ASIA sensory points from 2 levels above the neurological level to all levels below, including the sacral segments. Comparisons of EPT values above, at, and below the SCI were made at the three time points as well as comparisons of EPT data to ASIA assessment.ResultsThere was poor agreement between lowest normal level on EPT and ASIA assessment. Over time, EPTs tended to deteriorate above and at the ASIA level in AIS A patients with modest changes below the neurological level of injury (NLI), mainly where EPTs correlated with the zone of partial preservation. Sacral sparing was detected in one patient with EPT testing, but not with ASIA assessment. AIS B–D patients showed improvement at the ASIA level and extensive changes, both improvement and deterioration, below the NLI.ConclusionEPT testing has sufficient sensitivity to detect subclinical changes in sensory function as early as the first month post–SCI, which is not apparent in ASIA examination. In particular, the testing is able to show abnormalities at and around the injury site for both complete and incomplete SCI. In addition, EPT allows for the detection and monitoring of alterations, both improvements and deterioration, in the abnormal range of sensation.

Pedicular Anatomy of the First Sacral Segment in Transitional Variations of the Lumbo-Sacral Junction

The study aims to investigate the dimensions and angular orientations of the pedicles of the first sacral segment at the L5-S1 junctions affected by transitional variations. Measurement of parameters of the S1 pedicle and its orientation in sacra with (1) Accessory L5-S1 articulations, (2) Sacralisation of the L5, and (3) Lumbarisation of the first sacral segment, and comparing data with that observed in normal sacra. Lumbosacral fusion with instrumentation and screw fixation is commonly practiced to treat unstable L5-S1 junctions caused by a host of reasons. Though morphometric data pertaining to normal S1 pedicle structure is available in literature, it is hard to find such information regarding pedicles of first sacral segments associated with transitional variations. Transitional states at the lumbosacral junctions are often linked to development of L5-S1 instability. It thus becomes imperative to investigate S1 pedicular anatomy in context of these variations to prevent inadvertent surgical injuries and optimizing effects of screw placement in such sacral variations. S1 pedicle dimensions were measured in normal and L5-S1 transition affected sacra. Slope of the pedicle was measured with respect to the sagittal and the horizontal planes. Linear parameters were similar in the normal sacra and those with L5-S1 accessory articulations. Sacralisation reduced all dimensions including pedicle height, sagittal and transverse dimensions. Lumbarisation was associated with small length between the facet and the sacral promontory. Sacralisation reduced the sagittal angulation of the pedicles but substantially increased its downward slope. Lumbarised pedicles were more obtuse with the sagittal plane and less steep in front. S1 pedicle morphology and angulation in the first sacral segment are different from the normal in L5-S1 transitional situations and hence should be mapped accordingly in screw placements at the region in context of such common variations.

Transiliac lengthening with posterior lumbar-iliac percutaneous fusion in sacral hemiagenesis

Sacral agenesis is a term that applies to a wide range of developmental disorders of the lower portions of the spine and pelvis. Hemisacrum patients with all sacral segments present on one side of the spine, and decompensated lumbar rotoscoliosis, whit instability torac-pelvic that had transiliac lengthening of the lower extremity, accomplished by an innominate osteotomy with interposition of a rectangular iliac-bone graft in the osteotomy site, besides a posterior lumbar-iliac percutaneous fusion. We reported 5 adolescent patients, 2 men and 3 women, treated from 2000 to 2009, associated with average pelvic imbalance of 3.2 cm (2.5–4.5 cm) without other associated congenital anomalies. Patients classified as Vergara (Acta Ortop Mex 19:6–12, 2005) type IB unilateral partial agenesis of the sacrum, asymmetry of the pelvic ring there’s a torac-pelvic cifoscoliotic deformity. Mean age was 12.2 years-old (range from 8.2 to 13.7). The mean follow-up was 7.2 years (from 2 to 8). The consolidation process of the osteotomy site was in an average of 6.4 (5–8.7 weeks) (P = 0.036). None of the patients presented family medical history of diabetes on their mothers. None residual femoral nerve palsy. The procedure offers postural correction at the level of the pelvis, low morbidity and no additional operations were required to achieve the surgical objective. Level of evidence Level IV, therapeutic study: Case series (no, or historical, control group), Prospective: The study was started before the first patient was enrolled.

Iliosacral Screw Placement: Are Uniplanar Changes Realistic Based on Standard Fluoroscopic Imaging?

With the aim of improving the understanding of iliosacral screw placement, two hypotheses were tested: (1) standard intraoperative inlet and outlet images are not based on orthogonal coordinates, and (2) therefore making starting point and aim changes by moving perpendicular to the c-arm beam will displace the guide wire on the other intraoperative radiographic view. This is a prospective case series with review of intraoperative data from consecutive patients treated at a University Level I trauma center. The study group included ten consecutive patients with nondysmorphic upper sacral segments and unstable posterior pelvic ring injuries that required surgical treatment. Posterior surgical stabilization included iliosacral screw placement using a standardized three- view technique in the supine position. The main outcome measurement included the angles from the perpendicular required to achieve what have been considered the ideal inlet and outlet views intraoperatively. The angle arc for each patient created by the recorded angles was then determined. The average sagittal plane tilt required to achieve the ideal inlet view was 25 degrees (range, 21-33 degrees). The average sagittal plane tilt required to achieve the ideal outlet view was 42 degrees (range, 30-50 degrees). The average arc between the ideal inlet and outlet views was 67 degrees (range, 62-76 degrees). These views never created an orthogonal system. We commonly work in orthogonal systems. Within these systems, it is possible to make a uniplanar correction by moving perpendicular to one plane or radiographic view. The ideal views to image the safe zone for iliosacral screw placement do not create an orthogonal system. When this average angle arc is placed on a graphic model of the pelvis, it becomes clear that the plane of the radiographic beam of the ideal inlet view is collinear with the anterior aspect of the upper two sacral bodies. The outlet view is oblique to the upper sacral bodies. Surgeons must keep this in mind when using fluoroscopic views to insert iliosacral screws.

Unique sacral location of an arteriovenous fistula of the filum terminale associated with diastematomyelia and lowered spinal cords

Dear Sir, An arteriovenous fistula of the filum terminale arising from the artery of the filum terminale has recently been reported. Other authors report spinal dural and arteriovenous fistulae with lateral sacral artery supply [1–4]. We wish to bring to your attention an arteriovenous fistula of the filum terminale supplied by a lateral sacral artery associated with diastematomyelia and a tethered spinal cord in a 57-year old man. The patient suffered a progressive paraparesis for 3 weeks. At admission, the paraparesis was severe and accompanied by anal sphincter disturbances. MRI of the lumbar spinal canal (Fig. 1) showed a split and tethered spinal cord ending in the sacral spinal canal in an intraspinal lipoma. Moreover, there was extensive edema of the thoracic, lumbar, and sacral segments of the spinal cord as well as pathologic flow voids surrounding the myelum, suggesting a spinal arteriovenous fistula. A digital subtraction angiography (Fig. 2) revealed an arteriovenous fistula of the filum terminale at level S3-S4 fed by an enlarged anterior spinal artery, filling via a large sacral radicular artery arising from segment S2 with main supply from the left hypogastric artery. Drainage of the fistula occurred via enlarged perimedullary veins. At higher levels, no other segments of the artery of Adamkiewicz could be observed, but an additional tiny radicular artery filling the anterior spinal artery was found at level Th9 on the left. After introduction of a crossover sheath in the left internal iliac artery, a flow-directed microcatheter (MagicR, Balt Extrusion, Montmorency, France) was navigated via the supplying left S2-radicular artery into the anterior spinal artery up to the level of the shunt. Embolization was performed with a mixture of acrylic glue (Histoacryl, Braun, Tuttlingen, Germany) and lipiodol (Lipiodol UF, Guerbet, France) in a concentration of 1:4 enabling an angiographic cure of the fistula (Fig. 3). During the postoperative phase, there was some improvement of the paraparesis. Spinal vascular malformations are rare [5–7]. Seventy percent of all spinal vascular malformations are spinal dural arteriovenous fistulae that induce progressive neurologic symptoms [8]. The arteriovenous malformations can be divided into intramedullary and perimedullary types [7, 9]. Spinal cord arteriovenous malformations at the sacral level can be of two types: first, the dural arteriovenous fistulae arising at a sacral level as reported by Mhiri et al. [2] or at the conus medullaris [3, 4] and then the arteriovenous fistulae of the filum terminale, which are single-shunt arteriovenous fistulae fed by an anterior spinal S. Macht (*) :B. Turowski Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, Moorenstrasse 5, 40225 Dusseldorf, Germany e-mail: stephan.macht@med.uni-duesseldorf.de

Beta3‐adrenoceptors in the rat sacral spinal cord and their functional relevance in micturition under normal conditions and in a model of partial urethral obstruction

Beta3-adrenoceptor selective agonists are evaluated as a new treatment for patients with lower urinary tract symptoms . It is believed that β3-AR selective agonists exert their effects via a peripheral site of action. However, β3-ARs have been found in brain tissue. This study examined whether β3-ARs are present in rat sacral spinal cord, and whether there are differences in β3-AR expression between normal and partial urethral obstruction (PUO) animals, and furthermore assessed the functional relevance of spinal β3-ARs for micturition. Thirty-eight male Sprague-Dawley rats underwent either PUO or sham-operation. Two weeks after operation, half of the animals were used for histomorphological analysis. Remaining animals were used for functional experiments, where a β3-AR selective agonist, BRL 37344, was given intrathecally. Bladder function was assessed by continuous cystometry in non-anesthetized animals before and after drug administration. Beta3-ARs were found in sacral spinal cord segments with an accumulation in the ventral horn. There was a significant increase of β3-AR expression in obstructed rats. In functional experiments obstructed rats showed increased bladder weight, micturition frequency, spontaneous activity, and bladder pressures (all P < 0.05) compared to controls. Intrathecally administered BRL 37344 showed no effect in non-obstructed rats. In obstructed rats intrathecal BRL 37344 significantly reduced bladder pressures, spontaneous activity, and micturition frequency (all P < 0.05). Beta3-ARs are present in rat sacral spinal cord, and are significantly up-regulated after PUO. Besides their well-established peripheral site of action in the treatment of voiding dysfunction, β3-AR selective agonists might exert relevant effects at a central nervous site of action.

Quiste sinovial lumbar como causa de síndrome de cauda equina. Presentación de un caso y revisión de la literatura

We report the case of a 77-year-old woman who was admitted to our hospital with cauda equina syndrome. An urgent magnetic resonance imaging scan showed lumbar spinal canal compression at L4-L5 and L5-S1. An urgent laminectomy was performed and cystic lesions were extracted. On pathological examination, the lesions were identified as synovial cysts. The patient required rehabilitation and achieved good functional recovery, although sensory deficit remains in the sacral segments.

Facet Dimensions, Orientation, and Symmetry at L5–S1 Junction in Lumbosacral Transitional States

Study analyses dimensions, angular orientations, and symmetry of articular facets at the L5-S1 junction associated with transitional anomalies comprising (1) L5-S1 accessory articulations; (2) complete sacralization of the L5 vertebrae; and (3) completely lumbarized S1 sacral segments. Data were compared with same parameters evaluated in normal sacrum. Investigating probable morphologic differences in facet joints at the normal and transition affected lumbosacral junctions. Facet joints at the L5-S1 play an important role in load sharing and imparting stability at this area as well as are involved in conditions such as isthmic spondylolysis, degenerative spondylolisthesis, and osteoarthritis, giving rise to low back pain situations. Several morphologic variations at the lumbosacral junction have been studied and inconsistently alluded to be associated with these painful conditions. Lumbosacral transitional anomalies, on the other hand, have also been linked to low back pain situations. L5-S1 transitions have been shown to be associated with altered L5-S1 articular morphology as well as load-sharing pattern at the region. The analysis of L5-S1 zygapophysial anatomy in context of transitional anomalies at this region has rarely been documented. Both the superior articulating facets in the normal as well as in transition associated sacra were measured for (1) height, (2) width, (3) surface area, and (4) angulation of the articular surfaces with reference to the midsagittal plane. Data were also analyzed to find structural asymmetry between the two sides. Facets demonstrated smallest linear dimensions, surface areas, and maximum coronal orientation in lumbarized specimens. Facets areas associated with accessory articulations were also smaller and coronally oriented. Sacralization induced insignificant alteration in the facet morphology. Asymmetry (tropism) was observed in facets predominantly associated with accessory L5-S1 articulations. L5-S1 transitions possess altered facet morphology. These alterations are possibly related to low back pain situations.

Lewy body-related α-synucleinopathy in the spinal cord of cases with incidental Lewy body disease

Incidental Lewy body disease (ILBD) represents the early asymptomatic phase of Lewy body diseases (LBD), including idiopathic Parkinson's disease (PD). Although pathological disturbances in the spinal cord, which connects the brain to the peripheral nervous system, plays an important role, the pathology of ILBD has not been adequately examined. Eighteen ILBD and eight age-matched LBD cases were enrolled in the present study. LB-related pathology was immunohistochemically evaluated using anti-phosphorylated α-synuclein (pαSyn) antibodies, revealing LB-related pathology in the spinal cords of 15 (83.3%) of the ILBD cases. Attempts were made to identify the early pattern of pαSyn deposition in the spinal cord by comparing the cervical, thoracic, lumbar and sacral segments in detail. Most pαSyn-positive structures were distributed in and around the autonomic nuclei of the spinal cord. The intermediolateral nuclei in the thoracic segments (Th/IML) were the most frequently and severely affected region, suggesting that Th/IML are the first structures affected. Furthermore, following analysis of the distribution pattern of the pαSyn-positive structures, it is suspected that LB-related pathology progresses toward the caudal vertebrae by involving neurons in the spinal cord that are vulnerable to αSyn. It should be noted that the ILBD cases enrolled in the present study were in an earlier stage than the PD cases enrolled in the previous study, and that the present study provides new, previously undescribed information.

Spinal Cord Infarct in a Calf after Aortic Catheter Implantation

Spinal Cord Infarct in a Calf after Aortic Catheter Implantation

Spinal cord plasticity and acid-sensing ion channels involvement in a rodent model of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastro-intestinal disorder characterized by intractable chronic abdominal pain. In this study, we examined the possible spinal mechanisms underlying colonic hypersensitivity (CHS) using a non-inflammatory rat model of IBS induced by rectal enemas of butyrate, a short-chain fatty acid. We hypothesized that spinal plasticity could be responsible for CHS and that ASIC channels, which are known to support pain-elicited currents in the spinal cord, could contribute to central sensitization in our model of IBS. First, in order to determine if visceral pain relies on changes in spinal activity, we analyzed Fos expression in the spinal cord of rats treated with butyrate following a challenge with repetitive noxious colorectal distension. We found that Fos immunoreactivity was increased in thoracic T10–11–12, lumbar L1–2–6 and sacral S1 spinal segments. In control rats treated with saline, noxious repetitive colorectal distensions evoked Fos expression only in L1–2–6 and S1 spinal segments. Secondly, intrathecal injection of PcTx1, a specific ASIC1A antagonist, in the lumbar spinal cord completely prevented the development of CHS induced by butyrate. ASIC1 and 2 mRNAs, especially ASIC1A, were upregulated in the lumbar spinal cord. ASIC1A could thus contribute to spinal sensitization in our model of IBS, as it is supported by spinal colocalization of ASIC1A and Fos proteins. The whole data pinpoint a potential critical role of thoracic spinal cord in non-inflammatory pain states such as IBS and suggest that ASIC channels are part of the molecular effectors of central sensitization leading to visceral pain.

Quantification of the Upper and Second Sacral Segment Safe Zones in Normal and Dysmorphic Sacra

To quantify the obliquity and dimensions of the upper and second sacral segment iliosacral screw safe zones and to determine the differences between normal and dysmorphic sacral morphology. Retrospective cohort. University Level I trauma center. Fifty patients with pelvic computed tomography scans. All sacra were characterized as normal or dysmorphic based on plain pelvic radiographs and previously described criteria. Multiple computed tomography scan reconstructions were viewed and manipulated simultaneously with 6 degrees of freedom to allow for custom visualization in any plane. In each patient, a unique reconstruction plane was created perpendicular to the safe zone axis. The narrowest safe zone cross-sectional area was measured. Next, on simulated pelvic outlet and inlet views, safe zone obliquity and width were measured. Finally, the space available for a transverse screw was assessed. Measurements were performed for both upper and second sacral segment. Values for normal and dysmorphic safe zones were compared. Sacral dysmorphism was identified in 22 patients. In these sacra, the upper sacral segment safe zone cross-section was 36% smaller than in normal sacra (P < 0.001). No transverse screws could be placed, but accommodating for the caudal to cranial obliquity (30° versus 21° in normals, P < 0.001) and posterior to anterior obliquity (15% versus 4% in normals, P < 0.001) of the safe zone, an iliosacral screw at least 75 mm in length could be placed safely in 91% of patients. A transverse screw could be placed in 75% of normal sacra. In the second segment safe zone, the cross-sectional area was more than twice as large in dysmorphic sacra compared to normals (220 mm versus 109 mm, P < 0.001). The obliquity was not different on either the inlet or outlet views between groups. A transverse screw could be placed at this level in 95% of those with dysmorphic sacra and in only 50% of normal sacra. Sacral dysmorphism occurred in 44% of patients in this consecutive series. Many anatomic differences were consistently found between the two morphologies with clinical relevance to iliosacral screw placement. Specifically, the dysmorphic upper sacral segment safe zone is significantly smaller and more obliquely oriented but is still large enough to accommodate an iliosacral screw in nearly all patients. The second sacral segment safe zone is approximately transversely oriented in both sacral types but is more than twice as large in dysmorphic sacra. This segment may be a primary fixation opportunity in patients with sacral dysmorphism.

Radiographic Quantification and Analysis of Dysmorphic Upper Sacral Osseous Anatomy and Associated Iliosacral Screw Insertions

To quantify upper sacral dysmorphic osseous anatomy and assess its impact on second sacral segment iliosacral screw insertion. Retrospective evaluation of a prospective trauma database. Regional Level I trauma center. Twenty-four patients with unstable posterior pelvic ring disruptions and sacral dysmorphism were evaluated radiographically and second segment (S2) screws were placed using a standard technique. The sacral osseous pathway limits were measured using preoperative pelvic computed tomography at the upper and second sacral segments. The S2 screw location relative to the sacral nerve root tunnels and the maximum possible screw lengths for both S1 and S2 screws were evaluated with postoperative pelvic computed tomography. The S2 screw positions were graded as intraosseous, juxtaforaminal, or extruded. Preoperative and postoperative peripheral neurologic examinations were documented. The dysmorphic S1 width available for screw insertion averaged 13.2 mm. The S2 pathway width averaged 15.2 mm. The maximum potential screw length for the dysmorphic S1 averaged 100.8 mm and for S2 measured 151.9 mm. Twenty of 24 patients with S2 screws were intraosseous and in four patients were juxtaforaminal. There were no extruded screws. There were no neurologic injuries. Dysmorphic S1 segments are anatomically competent for routine screw fixation. The S2 segment provides a larger osseous site for screw insertion than S1 in dysmorphic sacrums. Significantly longer screws are possible in S2 compared with the dysmorphic S1 segment. S2 iliosacral screws can be safely and accurately accomplished using a standard technique in patients with unstable posterior pelvic ring disruptions and sacral dysmorphism. Safe screw insertions avoid iatrogenic nerve root injuries.