Lower Sacral Segments Research Articles

Pelvic incidence-guided reduction in transverse parts of U-shaped sacral fractures: Technical recommendations.

The purpose of this study is to present a surgical technique that simultaneously reduces and fixates the transverse parts of U-shaped sacral fractures. The sacral fracture was exposed through a posterior median approach. In a flexion injury, the rotation of the lower sacral segment is reduced by distraction along a pre-curved rod. Then, lordotic restoration is performed with a Weber clamp placed at the lower sacral segment through dragging. In an extension injury, longitudinal distraction is performed along the spinopelvic rod to reduce the vertical displacement. Next, the transverse displacement is reduced by a dissector placed between the upper and lower sacral segments through levering. The sagittal reduction on the lateral pelvic view was judged by PI. A regression analysis of Oswestry disability index (ODI) with Z-scores of PI, lumbar lordosis (LL), sacral slope (SS), and pelvic tilt (PT) was performed. At the 1-year follow-up, the average PI, LL, SS, and PT values were 51.6 (range: 43.1-76.0), 44.8 (34.6 - 60.1), 35.4 (18.1 - 48.0), and 16.7 (2.2-35.4) degrees, respectively. All patients were able to maintain an upright stance. The average ODI was 27.6% (2-72%). Surprisingly, the regression analysis demonstrated a significant linear relationship between ODI and LL (R2 = 0.367, p = .048) but not between ODI and PI (R2 = 0.227, p = .138). Using PI as guidance, the surgical procedures were helpful to reduce the PI of transverse sacral fractures into the normal range. However, the relationship between PI and the prognosis remains to be evaluated by future researches.

Spinopelvic dissociation in patients suffering injuries from airborne sports.

Spinopelvic dissociation which is also called U-type or referred to H-type sacral fractures with a transverse fracture line is an infrequent injury that results mainly from high-energy accidents. This results in an osseous dissociation of the upper central segment of the sacrum and the entire spine from the lower sacral segments. The purpose was to investigate the incidence of spinopelvic fracture in general among airborne injuries. Using our electronic patient records, we retrospectively investigated all sacral fractures related to airborne sports between 2010 and 2017. All injuries were classified according to the Roy-Camille, Denis, AOSpine and the Tile classification system. During the period of interest, 44 patients (18.7%) were admitted with sacral fractures after accidents obtained from airborne sports, including 16 spinopelvic dissociations (36.4%). The majority of these injuries were obtained from paragliding (75.0%), followed by BASE jumping (21.4%) and parachuting (4%). The mean injury severity score(ISS) in the spinopelvic dissociation group was significantly higher compared with other sacral fracture group (38.1 vs. 20.0; p < 0.001). Six lambda-type, four T-type, four H-type and two U-type injuries were identified. In total, four patients (25%) were found to have neurological impairment. For treatment, 87.5% of patients underwent subsequent surgical stabilization. Airborne sports have high potential for serious, life-threatening injuries with a high incidence of spinopelvic dissociation. In the literature, the prevalence of spinopelvic dissociation in sacral fractures is described to be between 3 and 5%. In our series, the prevalence is 36.4%. It is important to identify the potential injuries promptly for the further treatment. These slides can be retrieved under Electronic Supplementary Material.

Safe corridor for iliosacral and trans-sacral screw placement in Indian population: A preliminary CT based anatomical study

ObjectivesNonsurgical management of unstable pelvic ring injuries is associated with poor outcomes. Posterior pelvic ring injuries include sacroiliac joint disruption and sacral fractures or a combination of the two. Morbidity is high in non-operatively managed patients. Screw fixation is being increasingly used to manage unstable posterior pelvic injuries. Limitations include a steep learning curve and potential for neurovascular injury. This is the first study in Indian population to describe the safe corridor for screw placement and check the feasibility of screw in both upper and lower sacral segments. MethodsThis study involved retrospective analysis of 105 pelvic CT scans of patients admitted to the emergency department of a Level 1 trauma centre. Vertical height at the level of constriction (vestibule) of S1 and S2 was measured in coronal sections and anteroposterior width of constrictions was measured in axial sections. We created a trajectory for 7.3 mm cylinder keeping additional 2 mm free bony corridor around it and confirmed that bony limits were not breached in axial, coronal and sagittal sections. Whenever there was breach in bony limit we checked applicability of 6.5 mm screw. ResultsThe vertical height and anteroposterior width of vestibule/constriction of S1 was significantly higher in males, whereas S2 vestibule height and width were similar in males and females. Both male and female pelves were amenable to S1 Trans-sacral and S1 Iliosacral screw fixation with a 7.3 mm screw when a safe corridor of 2 mm was kept on all sides. However, when S2 segment was analysed, only 42.9% of male pelves and 25.7% of female pelves were amenable to insertion of trans-sacral 7.3 mm screw. ConclusionAn individualized approach is necessary and each patient’s CT must be carefully studied before embarking on sacroiliac screw fixation in Indian population.

A Case of Chordoma in Association with Rectal Carcinoma

A 74-year-old male patient presented with anal and sacral pain 18 months after abdomino-perineal resection for rectal cancer. Computerized tomography (CT) of the pelvis demonstrated a well defined mass anterior to the lower sacrum, posteriorly infiltrating and destroying the fourth and fifth sacral nerves and invading the right gluteal fossa. A 7.5 × 15 × 2 cm encapsulated mass was demonstrated during the operation using a posterior approach and the lower sacral segments together with the tumour were removed by amputation at S3 level. Histopathology revealed chordoma. This case is unique because of the rarity of chordoma in association with rectal tumour at the sacrococcygeal region.

Localization of the spinal network associated with generation of hindlimb locomotion in the neonatal rat and organization of its transverse coupling system.

The segmental organization of the hindlimb locomotor pattern generators and the coordination of rhythmic motor activity were studied in isolated spinal cords of the neonatal rat. All lumbar segments and many thoracic and sacral segments of the cord exhibited an alternating left-right rhythm in the presence of serotonin (5-HT) and N-methyl-D-aspartate (NDMA). Other thoracic segments exhibited a synchronized left-right rhythm or an irregular bursting activity. Transection of the cord at the thoracolumbar or lumbosacral junction abolished the rhythmicity of nonlumbar segments and had no affect on the rhythmicity of lumbar segments. A fast alternating rhythm persisted in rostral lumbar segments after transection of the cord at mid-L3. A much slower alternating rhythm was found in the detached caudal lumbar segments after elevation of the NMDA concentration. These findings suggest that neurogenesis of hindlimb locomotion is not restricted to L1/L2, and that the lumbar pattern generators exhibited rostrocaudal specialization. An alternating left-right rhythm persisted in lumbar cords of midsagittally split preparations that were kept with either L1, L2, L3, or L4 as the only bilaterally intact segment. An alternating rhythm persisted also in preparations that were midsagittally split up to T13-T12, or down to L4. Extension of these lesions led to a bilaterally synchronous rhythm or to left-right independent rhythms in the lumbar cord. These results indicated that the transverse coupling system in the caudal-thoracic and lumbar segments in specialized and that left-right alternation in the lumbar cord can be carried out by the cross connectivity, which is relayed at least through the T12-L4 segments. Bath application of the glycine receptor antagonist strychnine, or the gamma-aminobutyric acid-A (GABAA) receptor blocker bicuculline, induced in the presence of NMDA and 5-HT a bilaterally synchronous rhythm in any intact or detached segment of the cord and in midsagittally split preparations with few bilaterally intact upper thoracic or lower sacral segments. A strychnine-resistant left-right alternating rhythm was found in the presence of 5-HT and NMDA in preparations that were treated with the non-NMDA receptor blocker 6-cyano-7-nitroquinoxaline (CNQX) before and during the application of strychnine. Subsequent washout of CNQX immediately induced a bilateral synchronous rhythm. These results suggest that the phase relation between the hemicords during the rhythm is determined by a dynamic interplay between the excitatory and inhibitory cross connectivity, and that this interplay can be modulated experimentally. Local application of strychnine to L2 kept bilaterally intact in midsagittally split preparations perturbed but did not completely block the alternating pattern of the rhythm induced by 5-HT and NMDA. Local application of bicuculline under the same conditions prolonged the cycle time and had no effect on left-right alternation. These results, together with those described above, suggest that left-right alternation is mediated mainly by strychnine-sensitive glycine receptors with possible contribution of strychnine-resistant glycine receptors and/or GABAA receptors.

Sacral chordoma developing two years after low anterior resection for rectal cancer

A 43-year-old male with sacral chordoma associated with rectal cancer is herein reported. A presacral tumor with extensive destruction of S4 and S5 was found 2.5 years after a low anterior resection for advanced rectal mucinous carcinoma. Under the preoperative diagnosis of a solitary sacral metastasis of rectal cancer, the lower sacral segments together with the tumor were removed by amputation at S3. Histologically, the tumor was a chordoma composed of polyhedral cells with an abundant eosinophilic cytoplasm mixed with typical vacuolated physaliferous cells within a myxoid matrix. Colorectal cancer associated with an extracolic primary malignant neoplasm is not uncommon; however, this is only the second case of colorectal cancer associated with chordoma to the best of our knowledge.

Patterns and Significance of the Sacral Evoked Response (the Urologist’s Knee Jerk)

Summary— Neurological examination may fail to demonstrate any abnormality in patients who have neurogenic bladder dysfunction. Standard clinical methods will include full examination of segmental nerves to the level of S1 but will not include the lower sacral segments which control sphincter function. We describe a simple method of measuring the integrity and function of these segments of the cord. The method and the common patterns of response are described. The stimulus is physiological (not supramaximal), the response is measured with surface mounted electrodes at the urethral and anal sphincters and each measurement is the average response after 100 stimuli.

AN IMPROVED METHOD OF EPIDURAL ANALGESIA WITH REDUCED INSTRUMENTAL DELIVERY RATE

Abstract. A detailed study on a modified technique of epidural analgesia (EDA) for pain relief in obstetrics has been performed. the aim of the modifications was to reduce the number of instrumental deliveries and at the same time to make the delivery a s smooth a s possible for the baby. This was achieved by the use of an anaesthetic with a favourable ratio between neonatal and maternal plasma levels (Bupivacaine) in low concentration (0.25 %). a special technique of injection enabled us to limit the extent of the blockade. An epidural catheter was inserted between L2 and L3 and moved upwards 20 cm into the epidural space. 8‐10 rnl of the solution was then injected after a test dose. the blockade was continued by the repeated injection of smaller doses. As judged by the skin anaesthetic zones and by obstetric examinations, the patient was gradually positioned, during labour, from supine to half‐sitting. the catheter was withdrawn at the end ofthc first stage of labour so that the lower sacral segments could be blocked. a group of 100 patients treated with the technique described was followed. the number of instrumental deliveries in the present series (15%) was significantly lower than in similar series reported in the literature. the group of 100 patients treated with modified EDA was also compared with 100 control patients who received only conventional treatment without EDA. There were no differences in the number of abnormal presentations. while the number of caesarean sections and cases of atonic post‐partum bleeding was insignificantly lower in the EDA group. the difference in the number of instrumental deliveries–although somewhat higher in the EDA group‐was not statistically significant. the total length of labour was prolonged in the EDA group but EDA was not necessarily responsible for this undesired effect. The clinical status of the babies was found to be better after EDA than in the control group, asjudged from Apgar score. Furthermore. fetal bradycardia was significantly reduced with EDA. It is concluded that EDA. a s used in this study, not only is a preferable way of achieving pain relief in the mother but also offers a means of facilitating the birth process for the infant. reducing the incidence of pre‐ and post‐natal asphyxia.

An improved method of epidural analgesia with reduced instrumental delivery rate.

A detailed study on a modified technique of epidural analgesia (EDA) for pain relief in obstetrics has been performed. The aim of the modifications was to reduce the number of instrumental deliveries and at the same time to make the delivery as smooth as possible for the baby. This was achieved by the use of an anaesthetic with a favourable ratio between neonatal and maternal plasma levels (Bupivacaine) in low concentration (0.25%). A special technique of injection enabled us to limit the extent of the blockade. An epidural catheter was inserted between L2 and L3 and moved upwards 20 cm into the epidural space. 8-10 ml of the solution was then injected after a test dose. The blockade was continued by the repeated injection of smaller doses. As judged by the skin anaesthetic zones and by obstetric examinations, the patient was gradually positioned, during labour, from supine to half-sitting. The catheter was withdrawn at the end of the first stage of labour so that the lower sacral segments could be blocked. A group of 100 patients treated with the technique described was followed. The number of instrumental deliveries in the present series (15%) was significantly lower in similar series reported in the literature. The group of 100 patients treated with modified EDA was also compared with 100 control patients who received only conventional treatment without EDA. There was no differences in the number of abnormal presentations, while the number of caesarean sections and cases of atonic post-partum bleeding was insignificantly lower in the EDA group. The difference in the number of instrumental deliveries-although somewhat higher in the EDA group-was not statistically significant. The total length of labour was prolonged in the EDA group but EDA was not necessarily responsible for this undesired effect. The clinical status of the babies was found to be better after EDA than in control group, as judged from Apgar score. Furthermore, fetal bradycardia was significantly reduced with EDA. It is concluded that EDA, as used in this study, not only is a preferable way of achieving pain relif in the mother but also offers a means of facilitating the birth process for the infant, reducing the incidence of pre- and post-natal asphyxia.

犬の脊髄神経根の線維分析的研究

After a vital fixation of a dog into which an Orth's solution was infused through the aorta, the anterior and posterior roots of the 2nd (C_2), 3rd (C_3), 4th (C_4), 6th (C_6), 7th (C_7), and 8th (C_8) cervical nerves, of the 1st (Th_1), 2nd (Th_2), 4th (Th_4), 6th (Th_6), 9th (Th_9) and 12th (Th_<12>) thoracal nerves, of the 2nd (L_2), 3rd (L_3), 4th (L_4) and 6th (L_6) lumbar nerve and of the 2nd (S_2), 3rd (S_3), 4th (S_4), 5th (S_5), 6th (S_6) and 7th (S_7) sacral nerves were taken out. These roots, fixed with an Orth's solution again and then with a Muller's solution, were made into refrigerated cross section which, given a myelin sheath staining, were enclosed in a gelatin added glycerin and examined under an oil immersed lens of 1, 000 magnifications in order to measure the diameters of the medullated nerve fibers and their axis-cylinders. Results obtained were as follows. 1. Range of the fiber diameter distribution The diameters of the medullated nerve fibers ranged from 0.5μ to 21μ in the anterior roots, from 0.5μ to 23μ in posterior ones. There was the tendency that the fiber range was widest in those roots arised from the cervical and lumbar intumescences, and narrowest in those arised from the upper cervical, thoracical and lower sacral segments. 2. Figure of the fiber diameter distribution 1) Medullated nerve fibers composing the anterior roots show two peaks in their diameter distribution histograms. According to the distribution histograms and to the quantitative ratios between the small and large fiber groups, the anterior roots could be divided into two types : A (C_2, C_3, C_4, C_6, C_7, C_8, Th_1 L_6 and S_2) and B (Th_2, Th_4, Th_6, Th_9, Th_<12>, L_2, L_3, L_4, S_3, S_4, S_5, S_6, and S_7). Type A has two peaks of biological distribution, of about 5&acd;7μ and of 12&acd;17μ ; fibers in the large fiber group were far more numerous than those in the small fiber group, the average of the quantitative ratio between the two groups being about seven to three. In Type B, on the other hand, the large fiber group (peak on about 10&acd;15μ) shows biological distribution and the small fiber group (peak on about 2&acd;5μ) irregular distribution ; fibers in the small fiber group were more numerous than those in the large fiber group, the average of the quantitative ratio between the two groups being about six to four. From the results above mentioned, it could be speculated that the small fiber group includes the autonomic nerve fibers and the motor small nerve fibers, the large fiber group consisting of pure motor large nerve fibers. 2) Medullated nerve fibers constituting the posterior roots clearly showed two peaks in diameter distribution ; and the large fiber group (peak on about 8&acd;13μ) showed a considerable irregular distribution in contrast to a really biological distribution of the small fiber group (peak on about 2&acd;5μ). 3) Relation between the fiber diameter and g value In both anterior and posterior roots, g value showed about 45&acd;46% in the fibers of 2&acd;3μ in diameter, and it increased remarkably with widening of the fiber diameter. After getting to about 60% around the fibers of 17&acd;19μ in diameter. In g value curve, the difference of phase was reconized around the fibers of 5&acd;6μ in diameter which correspond to the shifting part from the small fiber group to the large one.

The distribution of dorsal root fibres on motor cells in the lumbosacral spinal cord of the cat, and the site of excitatory and inhibitory terminals in monosynaptic pathways.

The degeneration of cut, lumbosacral dorsal roots was traced by means of a silver method to the various sites of termination in the spinal cord of the cat. Particular attention was given to the pattern and distribution of dorsal root fibres terminating on motor cells. An attempt was made to correlate the synaptic organization of these monosynaptic pathways with the presence and distribution of short latency, direct excitation and inhibition (measured on the ventral roots) in comparable segments of the cord. Short latency excitation was found in the lower sacral segments to be correlated with dorsal root fibres terminating on cell bodies and dendrites of the motoneurons. Direct inhibition, largely or entirely uncontaminated by excitation, was identified in lower lumbar and upper and lower sacral segments. In these sites the terminal degeneration of the responsible dorsal root was limited to the dendrites and did not reach the cell bodies of the motoneurons. This consistent correlation between the spatial distribution of direct inhibition and terminals on motor dendrites suggests that this inhibition is monosynaptically and dendritically mediated, at least in part. Certain other interpretations are considered and relevant evidence obtained from intracellular microelectrodes placed in lower sacral motoneurones which were excited by ipsilateral and inhibited by contralateral dorsal root stimulation is discussed. Here, uncontaminated, monosynaptic excitation could be correlated with synaptic terminals on both cell bodies and dendrites of motoneurones.