Factors affecting fusion rate in adult spondylolisthesis

The authors examined factors affecting fusion rate in the surgical treatment of 89 consecutive adult patients with spondylolisthesis. Two factors significantly improved fusion rate: combined anterior and posterior fusion and rigid postoperative immobilization in the cast. In 65 patients with isthmic spondylolisthesis, the fusion rate was raised from 70% when posterior fusion alone was used to 88% when combined anterior and posterior fusion was used. In 20 patients with degenerative spondylolisthesis, frequent use of combined anterior and posterior fusion contributed to a high overall fusion rate of 95%. Among patients with isthmic spondylolisthesis, postoperative cast immobilization resulted in a higher fusion rate of 90% compared with a fusion rate of 63% obtained after brace immobilization.     

A King type II curve pattern treated with selective thoracic fusion: case report with 44-year follow-up.

The optimal surgical treatment of the King-Moe type II thoracic curve pattern is controversial. The issue of postoperative "decompensation" has arisen in conjunction with the use of third-generation instrumentation systems. This report presents the 44-year clinical and radiographic follow-up of a patient with a type II scoliosis treated with uninstrumented selective thoracic fusion using the criteria of King and Moe. The caudal extent of the fusion was defined by proper identification of the neutral and stable vertebra. At final follow-up, the patient remained well balanced and essentially pain free. Her level of function was "above average" for her age, as per SF-36 evaluation.     

Postoperative deep wound infection in adults after posterior lumbosacral spine fusion with instrumentation: incidence and management

The authors reviewed 817 instrumented lumbosacral fusions in adults and found an incidence of 3.2% deep wound infections. The primary focus of this study was the management of these infections, with particular attention to whether the implants needed to be removed. A consulting infectious disease specialist indicated that an acute infection of a low back fusion wound could not be healed without removal of the metallic implants. This opinion was in contrast to the authors' daily experience and prompted this study. The authors identified and reviewed 817 cases of instrumented posterior lumbosacral arthrodeses in adults. A detailed analysis of any case with a deep wound infection was performed and yielded and infection rate of 3.2% (26 patients). Of these, 24 achieved a clean, closed wound without removal of instrumentation through a protocol of aggressive debridement and secondary closure. Instrumentation removal is not necessary to obtain a clean, closed wound using an aggressive approach with early diagnosis, vigorous debridement in the operative room under general anesthesia, delayed primary or secondary closure, and appropriate antibiotic coverage.     

Convex growth arrest for progressive congenital scoliosis due to hemivertebrae

Thirteen patients with progressive congenital scoliosis due to hemivertebrae or hemivertebrae associated with other spinal anomalies were treated by convex anterior and posterior hemiarthrodesis and hemiepiphysiodesis. The average curve prior to operation was 46 degrees, average age was 3 years 6 months, and average followup was 6 years 6 months. One patient failed because of an inadequate length of anterior surgery which was successfully salvaged by further surgery. Twelve patients were successes: Seven had only cessation of the progressive curve, and five had progressive curve improvement greater than or equal to 5 degrees due to the arrested convex and persistent concave growth. This procedure is a valuable treatment modality for selected patients with congenital scoliosis.     

Intracellular preoptic and striatal monoamines in pregnant and lactating rats: possible role in maternal behavior

In many mammals, hormonal fluctuations during pregnancy and parturition produce neurochemical events that are necessary for the transition from a non-maternal state to a maternal state that occurs when infants are born. However, the nature of these events is mostly unknown. We investigated whether changes in dopamine (DA) and serotonin (5-HT) activity within the preoptic area (POA) and striatum, neural sites important for some maternal behaviors, could be part of this process. Female rats were sacrificed as either diestrus virgins, on pregnancy day 10 or 20, on the day of parturition, or on day 7 or 17 of lactation. Bilateral tissue punches from the POA, dorsolateral striatum (ST_dl), and nucleus accumbens (NA) were obtained and levels of intracellular DA and 5-HT analyzed with high-performance liquid chromatography with electrochemical detection (HPLC–EC). In the POA, DA was high in virgins and during early pregnancy, lowest on the day of parturition, and very high during lactation. Although there were no changes in the DOPAC to DA ratio (i.e., turnover), DOPAC levels also followed this pattern. 5-HT turnover in the POA was lower in virgins compared to other groups. In the ST_dl, DA turnover was highest during late pregnancy and on the day of parturition, while no changes in 5-HT measures were found. No significant effects were found in the NA. Therefore, decreased DAergic activity in the POA and increased DAergic activity in the ST_dl occurs around parturition, the time when maternal behavior emerges, and may influence its onset.     

Effects of unilateral suckling on nursing behavior and c-fos activity in the caudal periaqueductal gray in rats

In rats, suckling elicits kyphosis-the bilaterally symmetrical, upright, humpbacked nursing posture-and maximal expression of the immediate early gene c-fos in a region of the caudal periaqueductal gray (cPAG) that mediates the sensorimotor integration of kyphosis. We determined the effects of prepartum unilateral nipple removal on nursing behavior and c-fos expression during a 60-min mother-litter interaction on Day 7 postpartum. Compared with dams suckled by 6 pups bilaterally, dams suckled unilaterally displayed essentially normal maternal behaviors, including kyphosis. Unilaterally suckled dams, however, showed an increase in the abnormal prone nursing posture, a decrease in proportion of kyphotic nursing of total time over pups, and a 20% higher contralateral/ipsilateral ratio of cPAG neurons expressing c-fos. These results are consistent with an incompletely lateralized neural pathway conveying suckling stimulation to the cPAG and provide a mechanism whereby kyphosis is elicited by unilateral suckling when pups initiate nursing from their supine dam.     

Immunocytochemical investigation of nuclear progestin receptor expression within dopaminergic neurones of the female rat brain

Progesterone influences most processes involved in female reproduction, including ovulation, sexual behaviour, pregnancy, parturition, lactation and maternal behaviour. One neurotransmitter through which progesterone might regulate many of these functions is dopamine. To determine where in the brain progesterone might alter dopaminergic activity necessary for these and other processes in rats via cell nuclear progestin receptors, ovariectomized rats were injected subcutaneously with either 4 micro g oestradiol benzoate to induce high levels of hypothalamic progestin receptor expression, or oil, and perfused 48 h later. Dual-label immunocytochemistry was used to visualize cells having immunoreactivity (ir) for progestin receptors and tyrosine hydroxylase, a rate-limiting enzyme for dopamine synthesis. Many cells containing both progestin receptor-ir and tyrosine hydroxylase-ir were found throughout the periventricular hypothalamus of oestradiol-treated females. Conversely, very few cells in the hypothalamus of oil-treated controls contained progestin receptor-ir and, consequently, few dual-labelled cells were found in this group. The greatest percentage of tyrosine hydroxylase immunoreactive cells expressing progestin receptors in oestradiol-treated females was in, or near, the arcuate nucleus (A12 group), where up to 55% of tyrosine hydroxylase-expressing cells coexpressed progestin receptors. Notably, dual-labelled cells in oestradiol-treated females were also found more rostrally than previously reported, with approximately 15-20% of tyrosine hydroxylase-ir cells in the preoptic area/anterior hypothalamus (A14 group) also containing progestin receptor-ir. No dual-labelled cells were found for either group in the posterodorsal hypothalamus (A11 group), zona incerta (A13 group), retrorubral field (A8 group), ventral tegmental area (A10 group) or substantia nigra (A9 group) because little or no progestin receptor-ir was found in these sites. These data provide new information about the neural substrate where progesterone might regulate dopamine release in the preoptic area/anterior hypothalamus. Using more sensitive techniques than those used previously, they also confirm the relationship between progestin receptor and tyrosine hydroxylase in the arcuate nucleus, which could be important for the regulation of prolactin release throughout the female reproductive cycle. Additionally, although progesterone alters mesolimbic and nigrostriatal dopamine release, and the numerous behaviours that these pathways influence, these data again suggest that it does not do so via nuclear progestin receptor in dopaminergic cells of the ventral tegmental area and substantia nigra.