Dural ectasia: a likely cause of inadequate spinal anaesthesia in two parturients with Marfan's syndrome

Anesthetic management for cesarean section in two parturient with ascending aortic aneurysm: a case-based discussion

BACKGROUND

The anesthetic management of parturients with ascending aortic aneurysm for cesarean section can be particularly challenging, primarily because of increased risk for aortic dissection or aneurysm rupture.

CASE PRESENTATION

We present some aspects of the anesthetic management of two parturients with ascending aortic aneurysm for cesarean sections; amongst, the use of remifentanil with its effects on patient and newborn. We emphasize the importance of a cardio-obstetric team in the context of preoperative planning of such patients. Also, we reviewed some literature on the anesthetic management with its effect on peri-operative hemodynamic stability.

CONCLUSION

Maintaining hemodynamic stability is paramount in the prevention of the rupture or dissection of ascending aortic aneurysm during labor of parturient.

Quantitative measurement of dural ectasia: associations with clinical and genetic characteristics in Marfan syndrome

PURPOSE

Dural ectasia (DE) may significantly impact Marfan syndrome (MFS) patients' quality of life due to chronic lower back pain, postural headache and urinary disorders. We aimed to evaluate the association of quantitative measurements of DE, and their evolution over time, with demographic, clinical and genetic characteristics in a cohort of MFS patients.

METHODS

We retrospectively included 88 consecutive patients (39% females, mean age 37.1 ± 14.2 years) with genetically confirmed MFS who underwent at least one MRI or CT examination of the lumbosacral spine. Vertebral scalloping (VS) and dural sac ratio (DSR) were calculated from L3 to S3. Likely pathogenic or pathogenic FBN1 variants were categorized as either protein-truncating or in-frame. The latter were further classified according to their impact on the cysteine content of fibrillin-1.

RESULTS

Higher values of the systemic score (revised Ghent criteria) were associated with greater DSR at lumbar (p < 0.001) and sacral (p = 0.021) levels. Patients with protein-truncating variants exhibited a greater annual increase in lumbar (p = 0.039) and sacral (p = 0.048) DSR. Mutations affecting fibrillin-1 cysteine content were linked to higher VS (p = 0.009) and DSR (p = 0.038) at S1, along with a faster increase in VS (p = 0.032) and DSR (p = 0.001) in the lumbar region.

CONCLUSION

Our study shed further light on the relationship between genotype, dural pathology, and the overall clinical spectrum of MFS. The identification of protein-truncating variants and those impacting cysteine content may therefore suggest closer patient monitoring, in order to address potential complications associated with DE.

Anaesthetic considerations for elective cesarean section in a patient with a giant Tarlov cyst

Tarlov cysts are a pathological dilatation of the meninges. Their incidence is more frequent in women between 30 and 50 years of age. The imaging test of choice for diagnosis is MRI. Of unknown etiology, most cases are asymptomatic, but symptoms of radicular irritation, among others, may occur. The therapeutic possibilities are multiple, reserving surgical excision as the last option. We report a case of successful spinal anaesthesia for elective cesarean section in a patient with a giant Tarlov cyst but with potential airway compromise, in whom the risks of general anaesthesia would be increased. Anaesthetic management presents a challenge for the anesthesiologist, especially in situations where the patient presents an increased anaesthetic risk for general anaesthesia, as is the case in the obstetric patient.

Dural ectasia in Marfan syndrome and other hereditary connective tissue disorders: a 10-year follow-up study

BACKGROUND CONTEXT

Dural ectasia is widening of the dural sac often seen in patients with Marfan syndrome and other hereditary connective tissue disorders. Dural ectasia can cause specific symptoms and is associated with surgical complications. The knowledge on how and at which age dural ectasia develops is incomplete. There is no established gold standard for diagnosing dural ectasia, making it difficult to compare results from different studies.

PURPOSE

Our primary aim was to explore whether the radiological findings of dural ectasia changed after 10 years in an adult cohort with suspected Marfan syndrome. Our secondary aim was to re-evaluate the radiological criteria of dural ectasia.

STUDY DESIGN

Prospective cohort study.

PATIENT SAMPLE

Sixty-two persons from a cross-sectional study of 105 persons with suspected Marfan syndrome were included in a 10-year follow-up of dural ectasia. Forty-six were diagnosed with Marfan syndrome, 7 with Loeys-Dietz syndrome, and 5 with other hereditary connective tissue disorders. For comparison 64 matched hospital controls were evaluated.

OUTCOME MEASURES

Previously used radiological criteria for dural ectasia based on quantitative measurements of the lumbosacral spine.

METHODS

MRI of the lumbosacral spine was performed if not contraindicated, and if so then CT was performed. Differences in the study group between baseline and follow-up were assessed with paired Student t test, Wilcoxon rank signed test, and McNemar test. Receiver operating characteristic curves were constructed to assess the ability of radiological measurement to differentiate between the study and control group.

RESULTS

Fifty-two of 58 patients with hereditary connective tissue disorders and 11 controls had dural ectasia at follow-up. Forty-five Marfan patients had dural ectasia at follow-up vs. 41 at baseline. Five Loeys-Dietz patients had dural ectasia at follow-up vs. four at baseline. Twenty-four Marfan and 2 Loeys-Dietz patients had anterior sacral meningocele at follow-up, compared with 21 and 1, respectively, at baseline. Three Marfan patients developed herniation of a nerve root sleeve during follow-up. This was not seen in other individuals. The dural sac ended significantly lower at follow-up, and the dural sac ratio at level L5 was significantly increased from baseline in the Marfan patients.

CONCLUSIONS

In Marfan and Loeys-Dietz syndrome, dural ectasia may present or worsen during adulthood. The cut-off value of dural sac ratio at level S1 is suggested elevated to 0.64. The results from the present study may help as guidance for appropriate follow-up of patients with dural ectasia.

Marfan syndrome in a term-pregnant woman with aortic root dilatation between 40 and 45 mm

Marfan syndrome is a hereditary connective tissue disorder. The main cause of mortality in these patients is due to cardiovascular complications related to dilation of an aneurysm and dissection of the aortic root, a situation that increases their risk due to the physiological changes that occur during pregnancy, childbirth and puerperium. The case is presented of a pregnant woman with Marfan syndrome and aortic root dilatation of 42mm. The issues are discussed, such as the mode of delivery (vaginal delivery vs. caesarean section) depending on the aortic root diameter or the choice of type of anaesthesia (general vs. neuraxial) in these cases.

Successful spinal anaesthesia for caesarean section in a patient with Marfan syndrome complicated by dural ectasia

Marfan syndrome is a connective tissue disorder that may be complicated during pregnancy by aortic dissection. Caesarean section may be selected to avoid the haemodynamic challenges of vaginal birth. The common occurrence of dural ectasia in patients with Marfan syndrome is known to be associated with failed neuraxial anaesthesia. This report describes the administration of spinal anaesthesia to a woman with Marfan syndrome, and discusses why a hypobaric bupivacaine and opioid mixture, warmed to 37°C and injected intrathecally with the patient seated, produced successful surgical anaesthesia.

Epidural analgesia complicated by dural ectasia in the Marfan syndrome

Patients with the Marfan syndrome are considered to be high risk during pregnancy and warrant a complete multidisciplinary evaluation. One goal is to minimize hemodynamic fluctuations during labor since hypertensive episodes may result in aortic dissection or rupture. Although they may prevent these complications, neuraxial techniques may be complicated by dural ectasia. The case of a parturient with the Marfan syndrome and mild dural ectasia is presented. During attempted labor epidural placement, unintentional dural puncture occurred. A spinal catheter was used for adequate labor analgesia, and a resultant postdural puncture headache was alleviated by an epidural blood patch under fluoroscopic guidance.

Epidural Anesthesia for Cesarean Section in a Pregnant Woman with Marfan Syndrome and Dural Ectasia

Marfan syndrome (MFS) is a genetic disorder of connective tissue, characterized by variable clinical features and multisystem complications. The anesthetic management during delivery is debated. Regional anesthesia has been used with success during cesarean delivery, but in some MFS patients there is a probability of erratic and inadequate spread of intrathecal local anesthetics as a result of dural ectasia. In these cases, epidural anesthesia may be a particularly useful technique during cesarean delivery because it allows an adequate spread and action of local anesthetic with a controlled onset of anesthesia, analgesia, and sympathetic block and a low risk of perioperative complications. We report the perioperative management of a patient with MFS and dural ectasia who successfully underwent cesarean section using epidural technique anesthesia. The previous pregnancy of this woman ended with cesarean section with a failed spinal anesthesia that was converted to general anesthesia due to unknown dural ectasia at that time.

Lateral Position for Cesarean Delivery Because of Severe Aortocaval Compression in a Patient With Marfan Syndrome: A Case Report

Prompt recognition and management of hypotension resulting from aortocaval compression syndrome are essential to optimize the maternal and fetal outcomes. Management involves increasing leftward uterine displacement and sometimes full lateral positioning, although lateral position during cesarean delivery is typically considered to be impractical. We report an obstetric patient case of severe aortocaval compression syndrome resulting in hypotension and loss of consciousness that ultimately underwent cesarean delivery under general anesthesia in the lateral position. Performing cesarean delivery in the lateral position is virtually unreported, and this unique strategy prevented further symptoms of aortocaval compression and enabled safe delivery.

Loeys-Dietz syndrome and pregnancy: The first ten years

The physiological and haemodynamic changes that occur in pregnancy and the postpartum period increase the risk of aortic dissection. Loeys-Dietz syndrome results from mutations in the genes encoding components of the TGF-β signalling pathway; aortic pathology is of particular concern in this condition but other vascular abnormalities can also be present. Significant maternal morbidity and mortality has been described in patients with Loeys-Dietz syndrome, but successful and uncomplicated pregnancies are still possible. Nevertheless, all patients with this condition should, at present, be treated as very high risk in pregnancy and the postpartum period, until reliable risk prediction tools become available. This review summarises the recent advances in the understanding of the pathophysiology of this condition, and the management strategies currently advocated.

Aortopathy in pregnancy

Up to half of all aortic dissections and ruptures in women younger than 40 years are associated with pregnancy. In pregnancy, women with aortic disease such as arteritis and aortitis are at significant risk of aneurysmal formation and dissection with potential for catastrophic outcomes. Pregnancy places predisposed women at an increased risk of dissection due to physiological and hormonal changes that occur, particularly those with connective tissue disorders, genetic syndromes, congenital heart disease, and other heritable and acquired conditions involving the aorta. Thus, preconception counseling and preparation are advised to determine which patients may cautiously pursue pregnancy, to optimize medical management prior to conception (antihypertensive medications and anticoagulants in the setting of mechanical valves), to identify women in whom aortic root repair should occur prior to pregnancy, and lastly, those in whom pregnancy is contraindicated. Additionally, discussion of the heritable nature of many aortic conditions and associated syndromes is indicated. Preconception and genetic counseling, management by a multidisciplinary team, along with close echocardiographic surveillance and medical management, are recommended if precursors of dissection are identified.

Dural ectasia

Dural ectasia is one of the likely causes of incomplete or failed spinal anaesthesia. Its association with diseases like Marfans syndrome, neurofibromatosis, osteogenesis imperfecta, vertebral fracture, postopertative adhesions, trauma etc., is often overlooked as a reason for inadequate spinal anaesthesia. Greater than normal volume of cerebrospinal fluid in the lumber theca in dural ectasia is postulated to restrict the spread of intrathecally injected Local anaesthetic. Here, we report a case of failed spinal anaesthesia but successful epidural anaesthesia in later setting in a patient with dural ectasia.

Spinal anaesthesia in a patient with post-spine surgery dural ectasia

Dural sac ectasia is a very infrequent anatomical abnormality, usually caused by connective tissue diseases, as Marfan syndrome. Very few cases have been described being a consequence of a previous spine surgical procedure. We describe the case of an elderly patient who should be operated on twice due to sub-occlusive colon disease. Surgery was performed under spinal anaesthesia. A dural sac ectasia was suspected after the first procedure and the abdominal X-ray was reviewed. The characteristics of the anatomical alteration and the course of both anaesthetic procedures were described. X-ray and CT images were provided.

Dural ectasia in Marfan's syndrome: magnetic resonance imaging appearances and anaesthetic experience of three deliveries

Neuraxial anaesthetic techniques are considered useful to minimise haemodynamic stress during labour. In Marfan's syndrome, connective tissue abnormalities not only affect the thoracic aorta but also predispose to dural ectasia. A dural ectatic sac may cause difficulties with neuraxial analgesia and anaesthesia. We discuss magnetic resonance imaging appearances and anaesthetic experience of three deliveries in a parturient with stable echocardiographic findings. We consider that epidural analgesia and anaesthesia are a safe and pragmatic solution for labour and delivery. Lumbo-sacral magnetic resonance imaging at presentation will define dural ectasia and assist in management.

Marfan's syndrome and other aortopathies in pregnancy

Aortopathies, or disease affecting the aorta, are associated with a significant mortality risk for the mother and foetus during pregnancy because of an increased rate of aortic dissection. The hereditary aortopathies; Marfan's syndrome, bicuspid aortic valve, Loeys-Dietz syndrome, Ehlers-Danlos (type IV) syndrome, Turner's syndrome and nonsyndromic familial thoracic aortic aneurysm and dissection are all associated with an increased risk of aortic dissection particularly during the third trimester and early postpartum period. Maternal outcome in pregnancy depends on the underlying disorder and the aortic dimensions prior to pregnancy. The foetus has up to 50% chance of inheriting the underlying genetic defect. Vasculitis, particularly Takayasu's arteritis may also be a problem in pregnancy and predispose to aortic dissection. Prepregnancy review, including careful assessment of the aorta and prophylactic aortic surgery for an aortic aneurysm may reduce the risk of aortic dissection in pregnancy for some of the aortopathies but for women with Marfan's syndrome, Loeys-Dietz syndrome and Ehlers-Danlos (vascular type IV) who have had surgery, the risk of death remains high. A subgroup of women with Marfan's syndrome or a bicuspid aortic valve and normal aortic dimensions prepregnancy should do well in a pregnancy. Multidisciplinary pregnancy care with agreement on pregnancy follow-up, delivery and postpartum care with a crisis plan for an aortic dissection can improve pregnancy outcome and ensure prompt management of an aortic dissection should it occur.

Regional anesthesia in Marfan syndrome, not all dural ectasias are the same: a report of two cases

BACKGROUND

The anesthetic management of women with Marfan syndrome and dural ectasia undergoing Cesarean delivery remains controversial. We present two cases of patients with Marfan syndrome and dural ectasia where neuraxial anesthesia was used successfully. CASE 1: A 31-yr-old G1P0 female with Marfan syndrome presented for elective Cesarean delivery at 35(3/7) weeks' gestation. The magnetic resonance imaging of her spine revealed significant dural ectasia in the lumbosacral area with a mean lumbar dural sac area of 4.71 cm(2). Intrathecal administration of 0.75% hyperbaric bupivacaine 9 mg produced only limited perineal analgesia. The epidural catheter was titrated, and 0.5% bupivacaine 150 mg were required to achieve a T4 sensory level. CASE 2: A 34-yr-old G1P0 female with Marfan syndrome presented for elective Cesarean delivery at 37 weeks' gestation. The intrathecal administration of 0.75% hyperbaric bupivacaine 13.5 mg produced a T5 sensory level. Magnetic resonance imaging of her spine prior to discharge confirmed the diagnosis of moderate dural ectasia with a mean lumbar dural sac area of 3.61 cm(2).

DISCUSSION

The two patients described in this report responded differently to spinal anesthesia, most likely based on the severity of their dural ectasia. Although preoperative magnetic resonance imaging may help to identify patients at risk for a failed spinal, we suggest considering a combined spinal-epidural technique in cases of dural ectasia.

The pregnant patient with congenital heart disease

Advances in the surgical palliation and correction of congenital heart lesions have improved survival and increased the number of patients living into adulthood. Although pregnancy outcomes will be favorable for most patients with congenital heart disease, the cardiovascular challenges associated with pregnancy and delivery are best managed with a multidisciplinary approach during the puerperium. This review addresses the prevalence, physiology, risk assessment, peripartum complications, and anesthetic management of the pregnant patient with underlying congenital heart disease.

Dural ectasia in individuals with Marfan-like features but exclusion of mutations in the genes FBN1, TGFBR1 and TGFBR2

Mutations in the genes FBN1, TGFBR1, and TGFBR2 can result in heritable connective tissue disorders comprising the Marfan syndrome and the Loeys-Dietz syndrome. Dural ectasia is a characteristic manifestation of both syndromes. However, dural ectasia has not yet been investigated in connective tissue disorders that are unrelated to mutations in the FBN1, TGFBR1 or TGFBR2 genes. Here, we assessed dural ectasia in 33 individuals both with typical manifestations of heritable connective tissue disease and in whom mutations in all three genes had been excluded. We identified 19 individuals with dural ectasia (58%), who exhibited major skeletal manifestations of the Marfan syndrome more frequently than the remaining 14 persons without dural ectasia (p = 0.06). Moreover, only persons with dural ectasia fulfilled clinical criteria of the Marfan syndrome (p = 0.01). Conversely, aortic aneurysm (12 patients; p = 0.8), aortic dissection (five patients; p = 0.1), spontaneous dissection of the carotid arteries (five patients; p = 1), and mitral valve prolapse (13 patients; p = 0.4) were similarly frequent irrespective of dural ectasia. We conclude that dural ectasia is a marker for connective tissue disease which coincides with skeletal rather than with cardiovascular manifestations, and which may involve currently uncharacterized pathogenetic mechanisms and syndromes.

Epidural anesthesia for cesarean section in a patient with Marfan syndrome and dural ectasia -A case report-

Pregnancy is considered a period of high risk for cardiovascular complications in patients with Marfan syndrome. Therefore the choice of anesthetic technique for delivery should be focused on minimizing hemodynamic fluctuations, and preferably provide adequate post-operative pain control. For this purpose, neuraxial blocks, such as spinal or epidural anesthesia, may be deemed a safe option. However, dural ectasia is present in 63-92% of patients with Marfan syndrome, and the increased amount of cerebrospinal fluid volume is thought to be one of main reasons for spinal anesthesia failure. We report herein the peri-operative management of a patient with Marfan syndrome and dural ectasia for cesarean section using epidural anesthesia.

Health-related quality of life in Marfan syndrome: a cross-sectional study of Short Form 36 in 84 adults with a verified diagnosis

PURPOSE

To explore health-related quality of life as measured with Short Form 36 in adults with verified Marfan syndrome and to compare with the general population, other groups with chronic problems and studies on Marfan syndrome. Furthermore, to study potential correlations between the scores on the subscales of Short Form 36 and the presence of biomedical criteria and symptoms of Marfan syndrome.

METHOD

Cross-sectional study. Short Form 36 was investigated in 84 adults with verified Marfan syndrome.

RESULTS

The study group had reduced scores on all eight subscales of Short Form 36 compared with the general population, comparable with other groups with chronic diseases. Compared with earlier Short Form 36 results in Marfan syndrome, we found lower scores for social function, vitality, general health, bodily pain, and role physical. No correlations of substantial explanatory values were found between the Short Form 36 subscales and gender, body mass index, ascending aortic surgery, use of beta-blockers, visual acuity, joint hypermobility, fulfillment of the five major Ghent criteria, and number of major criteria fulfilled. Potential explanations are discussed.

CONCLUSION

Persons with Marfan syndrome have reduced scores for health-related quality of life as measured with Short Form 36, comparable with those in other chronic disorders and disabilities. The reduction does not seem to be related to biomedical criteria or symptoms of Marfan syndrome.

Transient paraplegia due to accidental intrathecal bupivacaine infiltration following pre-emptive analgesia in a patient with missed sacral dural ectasia

STUDY DESIGN

A case report with review of the literature.

OBJECTIVE

To highlight the need for careful magnetic resonance imaging evaluation for the presence of incidental lumbosacral dural anomalies before attempting caudal epidural interventions.

SUMMARY OF BACKGROUND DATA

Pre-emptive analgesia through the caudal epidural route provides good postoperative pain relief in spine surgeries. Several precautions have been advised in the literature. Presence of sacral-dural ectasia should be considered a relative contraindication for this procedure.

METHODS

A 50-year old woman underwent posterior instrumented spinal fusion for L4-L5 spondylolisthesis under general anesthesia. She received single shot caudal epidural analgesia at the start of the procedure.

RESULTS

After complete emergence from anesthesia, she had complete motor and sensory loss below the T12 spinal level, which reversed to normal neurology in 6 hours. Retrospective evaluation of the patient's magnetic resonance imaging showed an ectatic, low lying lumbosacral dural sac which had been overlooked in the initial evaluation. The drugs given by the caudal route have been accidentally administered into the thecal sac causing a brief period of neurologic deficit.

CONCLUSION

This unexpected complication has been reported only in the pediatric literature before. It is important to look for the presence of lumbosacral dural anomalies before planning caudal epidural injections in adults also. Sacral dural ectasia and other lumbosacral anomalies must be recognized as contraindications for caudal epidural pre-emptive analgesia for spine surgery. Other modes of postoperative pain relief should be tried in these patients.

Failed spinal anaesthesia: mechanisms, management, and prevention

Although spinal (subarachnoid or intrathecal) anaesthesia is generally regarded as one of the most reliable types of regional block methods, the possibility of failure has long been recognized. Dealing with a spinal anaesthetic which is in some way inadequate can be very difficult; so, the technique must be performed in a way which minimizes the risk of regional block. Thus, practitioners must be aware of all the possible mechanisms of failure so that, where possible, these mechanisms can be avoided. This review has considered the mechanisms in a sequential way: problems with lumbar puncture; errors in the preparation and injection of solutions; inadequate spreading of drugs through cerebrospinal fluid; failure of drug action on nervous tissue; and difficulties more related to patient management than the actual block. Techniques for minimizing the possibility of failure are discussed, all of them requiring, in essence, close attention to detail. Options for managing an inadequate block include repeating the injection, manipulation of the patient's posture to encourage wider spread of the injected solution, supplementation with local anaesthetic infiltration by the surgeon, use of systemic sedation or analgesic drugs, and recourse to general anaesthesia. Follow-up procedures must include full documentation of what happened, the provision of an explanation to the patient and, if indicated by events, detailed investigation.

Bupivacaine concentrations in the lumbar cerebrospinal fluid of patients during spinal anaesthesia

BACKGROUND

Data on bupivacaine concentrations in the cerebral spinal fluid (CSF) during spinal anaesthesia are scarce. The purpose of this study was to determine the concentration of bupivacaine in the lumbar CSF of patients with an adequate level of spinal anaesthesia after injection of plain bupivacaine 0.5%.

METHODS

Sixty patients with an adequate level of spinal block after standardized administration of plain bupivacaine 20 mg in men and of 17.5 mg in women were studied. To measure the CSF bupivacaine concentration, we performed a second lumbar spinal puncture and obtained a CSF sample at a randomized time point 5-45 min after the bupivacaine injection. In addition, we calculated the half-life of bupivacaine in the CSF and tested the hypothesis that the level of spinal block is related to the lumbar CSF bupivacaine concentration.

RESULTS

Men and women had CSF bupivacaine concentrations ranging from 95.4 to 773.0 microg ml(-1) (median 242.4 microg ml(-1)) and from 25.9 to 781.0 microg ml(-1) (median 187.6 microg ml(-1)), respectively. The large variability of bupivacaine concentrations obtained at similar times after subarachnoid administration made calculation of a meaningful half-life of bupivacaine in CSF impossible. There was no association between CSF bupivacaine concentration and spinal block level, and CSF bupivacaine concentrations for the same spinal block level differed between patients by six-fold.

CONCLUSIONS

There is a large variability of CSF bupivacaine concentrations in patients with an adequate level of spinal anaesthesia.

[Epidural and subarachnoid anesthesia and analgesia in adults: an update]

We present an update of the latest advances in clinical management and images of the most commonly used neuraxial techniques in epidural, subarachnoid, and combined spinal-epidural anesthesia and analgesia.

Large intrathecal volume: a cause of true failed spinal anesthesia

A 37-year-old woman scheduled for postpartum tubal ligation received two intrathecal doses of 2% hyperbaric mepivacaine (44 mg and 40 mg) and a subsequent single dose of 5% hyperbaric lidocaine (62.5 mg). Her sensory level never extended beyond S1. She subsequently underwent an uneventful general anesthetic, and had no residual sensory or motor deficits. An examination of the patient's lumbosacral magnetic resonance imaging (MRI) scan revealed an unusually large thecal volume. A large lumbosacral intrathecal volume may result in significant dilution or poor redistribution of hyperbaric local anesthetic. The final sensory level may be reduced or absent as a result. Intrathecal volume may be the most important non-modifiable factor affecting intrathecal distribution of local anesthetics; however, it cannot be easily measured or predicted. True failed spinal anesthesia should be distinguished from technical mishap, i.e., failing to introduce the anesthetic into the intrathecal space. The differential of a truly failed single-injection spinal anesthetic may include a large thecal volume, dural ectasias, cysts, and simple anatomic sacral restriction. To minimize maldistribution and neurotoxicity, the sum dose of all intrathecal local anesthetics administered for a single procedure should not significantly exceed the maximum recommended single-dose amount.

Complete failure of spinal anaesthesia in obstetrics

Intrathecal anaesthesia, either as a single shot-spinal or as part of a combined spinal-epidural technique, is now widely accepted as the management of choice for caesarean section. It generally produces rapid and predictable anaesthesia, yet occasionally fails for no apparent reason. Four case reports of seemingly inexplicable complete failure of intrathecal anaesthesia are presented, together with a literature review of other cases and possible causes of the failure, which include anatomical abnormality, drug failure and management failure.

Combined spinal-epidural analgesia for labor in a patient with Marfan’s syndrome

We report the management of a patient with Marfan's syndrome for labor analgesia and vaginal delivery using a combined spinal-epidural technique. The rapid onset of analgesia for the first stage of labor provided by the intrathecal opioid, combined with the slow and controlled onset of sensory anesthesia and sympathetic block provided by the dilute epidural local anesthetic, may make this technique particularly useful for labor and delivery in patients with Marfan's syndrome.

Marfan syndrome: clinical diagnosis and management

Marfan syndrome is a multisystem connective tissue disorder usually associated with mutation in fibrillin, and occasionally with mutation in TGFBR1 or 2. The clinical diagnosis is made using the Ghent nosology, which will unequivocally diagnose or exclude Marfan syndrome in 86% of cases. Use of a care pathway can help implementation of the nosology in the clinic. The penetrance of some features is age dependent, so the nosology must be used with caution in children. Molecular testing may be helpful in this context. The nosology cannot be used in families with isolated aortic dissection, or with related conditions such as Loeys-Dietz syndrome, although it may help identify families for further diagnostic evaluation because they do not fulfill the nosology, despite a history of aneurysm. Prophylactic medical (eg beta-blockade) and surgical intervention is important in reducing the cardiovascular complications of Marfan syndrome. Musculoskeletal symptoms are common, although the pathophysiology is less clear--for example, the correlation between dural ectasia and back pain is uncertain. Symptoms in other systems require specialist review such as ophthalmology assessment of refractive errors and ectopia lentis. Pregnancy is a time of increased cardiovascular risk for women with Marfan syndrome, particularly if the aortic root exceeds 4 cm at the start of pregnancy. High-intensity static exercise should be discouraged although low-moderate intensity dynamic exercise may be beneficial. The diagnosis and management of Marfan syndrome requires a multidisciplinary team approach, in view of its multisystem effects and phenotypic variability.