A case report of an unusual cause of postoperative leg pain after posterior lumbar fusion.

We report the case of a 36-year old man who underwent elective posterior lumbar spinal fusion after presenting with bilateral leg pain with associated back pain. He had undergone a L5/S1 discectomy in 2001, which provided good symptomatic relief. On this admission, he underwent elective L4-S1 posterolateral fusion and bilateral L4/5 and L5/S1 decompression. Intra-operatively a pedicle screw had to be re-inserted after fluoroscopy confirmed a lateral breech. The patient had no major postoperative complications until the sixth day when the patient re-presented with acute leg pain and weakness. Following a local multidisciplinary meeting (MDT) an MRI showed a large haematoma at the right psoas muscle. CT angiogram confirmed a bleeding lumbar segmental vessel at the site of the previous misplaced screw and an emergency fluoroscopic guided embolisation of the vessel was performed. The patient recovered well post operatively and was discharged back to the community 12 days later. Haemorrhage, as in this case a psoas haematoma should be considered as one of the differentials in patients with recurrent post-operative radiculopathy following posterior lumbar spine fusion. This should be suspected particularly if there has been a misplacement of one or more screws as this can cause injury to blood vessels and be fatal for the patient.

Inequitable allocation of deep community wells for reducing arsenic exposure in Bangladesh.

Community wells that extend deeper than most private wells are crucial for reducing exposure to groundwater arsenic (As) in rural Bangladesh. This study evaluates the impact on access to safe drinking water of 915 such intermediate (90-150 m) and deep (>150 m) wells across a 180 km2 area where a total of 48,790 tubewells were tested with field kits in 2012-13. Half the shallow private wells meet the Bangladesh standard of 50 µg/L for As in drinking water, whereas 92% of the intermediate and deep wells meet the more restrictive World Health Organization guideline for As in drinking water of 10 µg/L. As a proxy for water access, distance calculations show that 29% of shallow wells with >50 µg/L As are located within walking distance (100 m) of at least one of the 915 intermediate or deep wells. Similar calculations for a hypothetical more even distribution of deep wells show that 74% of shallow wells with >50 µg/L As could have been located within 100 m of the same number deep wells. These observations and well-usage data suggest that community wells in Araihazar, and probably elsewhere in Bangladesh, were not optimally allocated by the government because of elite capture.

The effect of leg length discrepancy on pelvis and spine kinematics during gait.

There are assumptions that leg length discrepancy (LLD) may cause low back pain by creating pelvis obliquity and lumbar scoliosis. Although individuals with LLD develop compensatory movements in the lower limbs and pelvis during walking, few investigations have attempted to identify kinematic variables of the upper body. This study aims to gain an understanding of how simulated LLD influences three-dimensional motion of the pelvis and spine. Seven male participants were required to walk barefoot at a preferred speed. Three LLD conditions (1, 2, and 3cm) were simulated using modified pieces of high density EVA attached to the right foot. An optoelectronic motion analysis system was used to record kinematic data of the pelvis and spine (lumbar, lower and upper thoracic segments) for each condition. Differences in range of motion and patterns of movement for the pelvis and lumbar spine were minimal between barefoot and LLD conditions. These observations could be attributed to various kinematic compensatory strategies within the lower limbs which require further in-depth investigation.

IL-6 induced by Staphylococcus aureus infection prevents the induction of skin allograft acceptance in mice.

Clinical correlations between bacterial infections and rejection suggest a hypothesis that innate immune stimulation by bacterial infections results in the production of inflammatory cytokine that facilitate bystander T-cell activation, increased alloreactivity and inhibition of tolerance induction. Previous studies demonstrated that IFNß produced during an infection with a model bacterium, Listeria monocytogenes, prevented the induction of transplantation tolerance in mice with anti-CD154 and donor-specific transfusion (DST) (1). We investigated the impact of two clinically relevant bacterial infections at the time of transplantation on the ability of anti-CD154 and DST to induce skin allograft acceptance in mice. Staphylococcus aureus (SA) infection prevented skin allograft acceptance whereas maximally tolerated doses of Pseudomonas aeruginosa infection had no effect. SA induced an acute production of IL-6, which was necessary and sufficient for the prevention of skin allograft acceptance. Furthermore, a single pulse of methylprednisolone modulated IL-6 production during SA infection and facilitated skin allograft acceptance in SA-infected recipients. Taken together, our results suggest that bacterial infections elicit specific proinflammatory cytokines signatures that can serve as barriers to tolerance induction, and that inhibiting the production of or neutralizing these inflammatory cytokines can synergize with costimulatory blockade-based therapies to facilitate the development of transplantation tolerance.

Infection with the intracellular bacterium, Listeria monocytogenes, overrides established tolerance in a mouse cardiac allograft model.

Infections and TLR signals at the time of transplantation have been shown to prevent the induction of tolerance, but their effect on allografts after tolerance has been established is unclear. We here report that infection with Listeria monocytogenes precipitated the loss of tolerance and the MyD88- and T cell-dependent rejection of accepted cardiac allografts in mice. This loss of tolerance was associated with increases in the numbers of graft-infiltrating macrophages and dendritic cells, as well as CD4(+)FoxP3(-) and CD8(+) T cells. Rejection was also associated with increased numbers of graft-infiltrating alloreactive as well as Listeria-reactive IFNgamma-producing T cells. Rejection of the established grafts required both IL-6 and IFNss, cytokines produced during acute Listeria infection. However, IL-6 and IFNss alone, even when present at higher concentrations than during Listeria infection, were insufficient to break tolerance, while the combination of IL-6 and IFNss was sufficient to break tolerance. These and in vitro observations that IL-6 but not IFNss enhanced T cell proliferation while IFNss but not IL-6 enhanced IFNgamma production support a hypothesis that these cytokines play nonredundant roles. In conclusion, these studies demonstrate that the proinflammatory effects of infections can induce the loss of tolerance and acute rejection of accepted allografts.

A study of the mechanical stability of scoliosis constructs using variable numbers of sublaminar wires.

Sublaminar wiring with posterior instrumentation is one of the methods used when long fusions involving 10-12 thoracolumbar levels are required. Classically, wires are used at every consecutive level to make the construct as rigid as possible, although complications like dural tears, cerebrospinal fluid leak, and neurological deficit have been reported during their passage. We compared the mechanical stability under torsional strain of five specimens of each of three construct designs, by static and fatigue testing, using an electro-servo-hydraulic testing machine. In construct A, a contoured Hartshill rectangle was used from T2 to L2, with sublaminar wires passed at every level. In construct B, the Hartshill rectangle was wired to the spine at every alternate level. In construct C, every alternate level was wired except at the proximal end, where two consecutive levels were wired. Industrially fabricated spine models were used to prepare these constructs. The intervertebral motion within the construct was measured using the Fastrak magnetic field sensor device. On static testing, no statistically significant difference was found in the rotational displacement of the three construct designs. On fatigue testing, all samples of construct B consistently failed, with breakage of the wire at the most proximal level on the left side. But on adding additional wires to the next level (construct C), all five samples withstood fatigue testing at 300 N load to three million cycles. We conclude that wiring alternate levels instead of every level does not compromise the stability of the construct, provided that the most proximal two levels are consecutively wired. This practice would minimise the risk of dural tears and cord damage during wire passage and reduce surgical time, not to mention the economic benefits.