Do positional changes of the inferior alveolar canal after sagittal split mandibular osteotomy affect neurosensory recovery?

The purpose of this study was to assess the pre- and postoperative position and dimensions of the inferior alveolar canal (IAC) following sagittal split osteotomy (SSO) and identify any association with postoperative neurosensory deficit (NSD) at 1 year. This retrospective cohort study enrolled consecutive patients who had SSO performed to correct skeletal malocclusion. The pre- and postoperative cone beam computed tomography data were superimposed to visualize differences in IAC position and dimensions. Subjective and objective neurosensory tests were used to determine NSD in the inferior alveolar nerve distribution. A total of 20 subjects were included. The preoperative distance from the lateral cortex of the IAC to the inner aspect of the lateral cortex of the mandible was significantly greater in sides with NSD when compared to sides without NSD (P = 0.01). A significantly greater reduction in the postoperative distance measurement was seen in sides with NSD when compared to sides without NSD (P = 0.01). The magnitude of mandibular movement was significantly increased in sides with NSD (P = 0.02). The preoperative location of the IAC, as well as certain changes in the mediolateral and vertical positions as a result of SSO, are risk factors for postoperative NSD.

[Organs at risk in radiation therapy of head and neck tumors: practical aspects in their delineation and normal tissue tolerance]. / Organes à risque en radiothérapie conformationnelle des tumeurs de la tête et du cou : aspect pratique de leur délinéation et des contraintes de dose.

The aim of this article is to provide some practical guidelines for the delineation of organs at risk in intensity-modulated radiation therapy (IMRT) in head and neck cancer, drawn from anatomic, radiology, physiopathology date which will take into account the daily imperatives of radiation oncologists. Standardizing the delineation of organs at risk by consensus, might help for an objective comparison of toxicities induced by radiotherapy.

Hydronephrosis with diffuse or segmental cortical thinning: impact on renal function.

PURPOSE: Management of hydronephrosis has changed considerably with the routine use of prenatal ultrasonography. Increased dependence is now placed on nuclear renographic differential renal function, and many urologists consider surgical intervention for ureteropelvic junction obstruction with significant decrease in renal function (less than 40%). Correlation between differential renal function and the degree of dilatation diagnosed by ultrasound has not been reported. In addition, no difference between hydronephrosis associated with either diffuse or segmental cortical thinning has been made, as both are classified as grade IV according to the Society of Fetal Urology classification. Based on clinical observation we hypothesized that hydronephrotic grade IV kidneys with diffuse parenchymal thinning are associated with worse renal function and are distinct from those with segmental cortical thinning. MATERIALS AND METHODS: We performed a retrospective study of patients who underwent pyeloplasty between January 1996 and December 1998. Hydronephrosis was graded according to Society for Fetal Urology classification and all diuretic renograms were performed in a standardized fashion. Grade IV kidneys were divided into IVA (segmental cortical thinning) and IVB (diffuse cortical thinning). Statistical correlation of grade and differential renal function was performed using a chi-square test. RESULTS: Images were available for review in 77 patients. Average patient age at intervention was 20.4 months and 7.6 years of the prenatally and postnatally detected hydronephrosis groups, respectively. Of the 77 cases 25 had grade IVA and 18 had grade IVB hydronephrosis. Of the grade IVB hydronephrosis cases 66% had less than 40% differential renal function compared to 24% in group IVA (p <0.05). CONCLUSIONS: Patients with grade IVB hydronephrosis secondary to ureteropelvic junction obstruction have a higher risk of significant decrease in renal function. Group IVA has significantly better function than group IVB and characteristics similar to grade III hydronephrosis cases. Grade IVB hydronephrosis should monitorized closely as earlier intervention may be warranted to avoid progressive deterioration of renal function.

The origin of platyrrhines: An evaluation of the Antarctic scenario and the floating island model.

This paper evaluates whether 1) protoplatyrrhines could have migrated to South America via Antarctica, and 2) the floating island model is a plausible transoceanic mode of dispersal for land vertebrates like protoplatyrrhines. Results show that Eocene Antarctica and Australia supported large and dense forests, and that the Antarctic fauna was comprised of many species of vertebrates, including placental and marsupial land mammals. However, no primate remains have ever been reported from these continents. Antarctica and South America were connected until the Middle Eocene (i.e., after the oldest Asian anthropoids), but two major water barriers existed between Antarctica and Asia since the Early Eocene. The Eocene and Oligocene water gap separating Africa and Antarctica was excessively large. Thus, all scenarios involving an Antarctic route have been rejected. The African scenario is difficult to falsify because only one water barrier existed, both paleowinds and paleocurrents were favorable, and Paleogene African anthropoids show phylogenetic affinities to platyrrhines. I tested whether a journey on a hypothetical floating island over the Paleogene Atlantic Ocean exceeds the survival limit of a genetically viable group of animals such as protoplatyrrhines. Studies of water deprivation suggest that they could have been able, with a body weight averaging 1 kg, to survive without water for at least 13 days. I have used the present Atlantic Ocean as a model for the velocity of Paleogene paleowinds and paleocurrents. Considering winds as the key accelerating force of floating islands, the Paleogene Atlantic water barrier could have been crossed, in the most conservative scenario, in 8 days at 50 Mya, 11 days at 40 Mya, and 15 days at 30 Mya. In order to survive a transoceanic journey, however, protoplatyrrhines had to be preadapted to strong seasonal variations in water availability in their original (African) environment. Once on the sea, their brains would have physiologically interpreted the rarity of water as the beginning of the dry season, and the group would have switched its diet to alternative foods, i.e., everything available on the floating island.

Supranormal renographic differential renal function in congenital hydronephrosis: fact, not artifact.

PURPOSE: Children with unilateral hydronephrosis, who had been prospectively examined with diethylenetriaminepentaacetic acid (DTPA) and dimercapto-succinic acid (DMSA) renography, were evaluated to determine whether supranormal renographic differential renal function exists. MATERIALS AND METHODS: A total of 54 children with congenital single system hydronephrosis underwent abdominal ultrasound, voiding cystourethrogram, and DTPA and DMSA renal scans. None had abnormalities of the bladder or contralateral kidney. Differential renal function greater than 55% was defined as supranormal. RESULTS: Of the 54 patients 15 (28%) with a median age of 4 months (range 0.5 to 66) were identified with supranormal renographic renal function on either DTPA or DMSA. Supranormal renographic renal function was detected by DMSA in 9 cases (mean 57+/-2%), DTPA in 8 (mean 58+/-2%) and both in 2 (mean 57+/-2%). Average function demonstrated in the 15 patients was 55+/-3% (range 51 to 62) with DMSA which was not different from that found with DTPA (mean 55+/-4%, range 46 to 61%). The kidneys with supranormal renographic renal function were significantly larger than hydronephrotic controls according to longitudinal parenchymal area on DMSA. Mean followup was 20 months for 13 patients, with 8 of 13 (62%) undergoing pyeloplasty. Followup DTPA renal scans available in 9 children revealed persistent supranormal function in 6, despite pyeloplasty in 3. CONCLUSIONS: Supranormal renographic differential renal function does exist in congenital hydronephrosis and when found the kidneys are consistently enlarged. The position of supranormal renographic renal function in the management algorithm of hydronephrosis remains to be elucidated as it does not appear to be a benign prognostic factor.

Magnetic resonance imaging in children with voiding dysfunction: is it indicated?

PURPOSE: We evaluated the role of magnetic resonance imaging (MRI) of the lumbosacral spinal cord in children with complicated voiding dysfunction and normal neuro-orthopedic examination. MATERIALS AND METHODS: We reviewed the records of 32 consecutive children with complicated enuresis who were referred for neurosurgical evaluation, including those with a history of refractory voiding dysfunction or incontinence associated with persistent vesicoureteral reflux, encopresis, or associated leg or back pain. Nine patients were excluded from study because of urethral or anorectal anomalies, or failure to meet the inclusion criteria. Eligible for study inclusion were 23 children with a mean age of 8.9 years. Complete neurological and orthopedic examinations were normal in all patients except 1 with mild scoliosis and 1 with congenital facial palsy. RESULTS: Urodynamic studies revealed instability in 14 cases, hypertonia in 7, hyporeflexia in 2 and detrusor-sphincter dyssynergia in 4. Skeletal abnormalities, mostly spina bifida occulta, were detected in 16 of the 23 children (70%). Spinal MRI was normal in 21 patients (91.3%), including 1 with a tethered cord and lipoma associated with a complex skeletal abnormality, and 1 with a nonprogressive, nonsurgical T7 to T9 syrinx. Only the case of lipoma required neurosurgical intervention. CONCLUSIONS: The value of MRI is limited in children with voiding dysfunction and a normal neuro-orthopedic assessment. This study should be reserved for patients with associated neuroorthopedic findings or complex skeletal deformity on plain x-ray.

Bladder function before and after selective dorsal rhizotomy in children with cerebral palsy.

PURPOSE: Approximately a third of children with cerebral palsy are expected to present with dysfunctional voiding symptoms. Selective dorsal rhizotomy, which is indicated for managing lower extremity spasticity in children with cerebral palsy, also has the potential of affecting bladder function. We evaluate the impact of selective dorsal rhizotomy on bladder function by comparing preoperative and postoperative symptoms, and urodynamic parameters in children undergoing selective dorsal rhizotomy for spasticity. MATERIALS AND METHODS: We reviewed urodynamic studies in 25 boys and 15 girls with a mean age plus or minus standard deviation of 5.43+/-2.1 years who underwent selective dorsal rhizotomy for spasticity at our institution between January 1992 and September 1995. Urodynamics were performed preoperatively only in 22 patients, preoperative and postoperatively in 13, and postoperatively only in 5. Preoperative urodynamic studies were done within 2 weeks of surgery and postoperative studies were done at least 6 months after surgery (mean 1.32+/-0.65 years). RESULTS: Of the 35 patients with preoperative urodynamic studies total bladder capacity, pressure specific volumes and full resting pressure were abnormal for age in 23 (65.7%). In addition, 17 of the 23 children (74%) were completely asymptomatic. In the group that underwent preoperative and postoperative urodynamic studies there was significant improvement in total bladder capacity (p <0.005) and pressure specific volumes (p <0.005) using the paired Student t test. All children had neurological improvement postoperatively, 5 of 7 (71%) who were incontinent preoperatively became continent and none had deterioration on urodynamics. CONCLUSIONS: At least half of the children with spastic cerebral palsy have clinically silent bladder dysfunction. Selective dorsal rhizotomy improves spasticity and significantly improves bladder storage characteristics. We propose that urodynamic studies be included in the evaluation of children with spastic cerebral palsy who are possible candidates for selective dorsal rhizotomy to treat lower limb spasticity.

Long-term results of percutaneous endopyelotomy in the treatment of children with failed open pyeloplasty.

PURPOSE: We reviewed our experience with the safety and long-term efficacy of percutaneous endopyelotomy in children with secondary ureteropelvic junction obstruction who previously underwent open pyeloplasty. MATERIALS AND METHODS: Nine patients a median of 7 years old underwent endopyelotomy between June 1985 and July 1995. Anderson-Hynes pyeloplasty had previously been performed in all children. Antegrade endopyelotomy was done with a cold knife in conjunction with balloon dilation in some cases. Postoperative stenting lasted 6 weeks. RESULTS: The median interval between pyeloplasty and endopyelotomy was 7.5 months. Mean operative time was 240 minutes. Percutaneous endopyelotomy was successful in 8 of the 9 patients. One patient who required repeat endopyelotomy after 4 years is presently well at 5 years of followup. Average followup was 5.6 years (range 2 to 10). There was a low morbidity rate, including 1 case of urinary tract infection, 1 of pneumonia and 1 that required blood transfusion. CONCLUSIONS: Percutaneous antegrade endopyelotomy is a safe, effective and durable alternative for children who previously underwent unsuccessful pyeloplasty.

Impact of urodynamic studies on the surgical management of spinal cord tethering.

To determine the usefulness of urodynamic studies in the management of children with a suspected tethered spinal cord, the authors retrospectively reviewed case records of 25 patients evaluated both pre- and postoperatively using this diagnostic adjunct. All patients were also evaluated with magnetic resonance imaging or computerized tomography myelography. Seven patients who presented initially with orthopedic deformity, skin stigmata, and neurological problems underwent primary cord untethering (Group 1). All seven patients were urologically asymptomatic; all but one had normal findings on urodynamic study. Eighteen patients with prior myelomeningocele closure underwent secondary untethering (Group 2). They presented with urological (11 cases), neurological (three cases), or both urological and neurological (four cases) deterioration. All patients underwent surgery via a microsurgical technique. At a mean follow-up time of 2 years, the only Group 1 patient with preoperative abnormal urodynamic findings normalized following untethering, whereas another asymptomatic patient showed worsened results on his postoperative study. In Group 2, all seven patients with preoperative neurological deterioration improved. Ten of the 15 patients who had isolated or associated preoperative clinical urological deterioration improved or stabilized, whereas five displayed continued deterioration in their bladder function. With respect to urodynamic studies, there was a significant increase in total and pressure-specific bladder capacities following untethering. We conclude that urodynamic studies are useful both diagnostically and in follow-up examinations of patients with tethered cord, that disturbances identified by these studies often precede clinical manifestations of deterioration, and that spinal cord untethering favorably influences the urological status in most patients.

Human chorionic gonadotropin but not the calcitonin gene-related peptide induces postnatal testicular descent in mice.

The androgen-regulated paracrine factor, calcitonin gene-related peptide (CGRP), has been proposed as a possible mediator of testicular descent. This peptide has been found to increase rhythmic contractions of gubernaculae and is known to be released by the genitofemoral nerve. We have investigated the ability of CGRP to induce premature testicular descent. CGRP was administered alone, or in combination with human chorionic gonadotropin (hCG) to C57BL/6 male mice postnatally. The extent of testicular descent at 18 days postpartum was then ascertained. The potential relationship between testicular weight and descent was also examined. Our results show that testes of mice treated with either hCG alone, or in combination with 500 ng CGRP, were at a significantly lower position than those of controls by 16% and 17%, respectively. In contrast, mice treated with 500 ng of CGRP alone had testes at a higher position when compared to those of controls, by 19%. In mice treated with 50 ng of CGRP alone or in combination with hCG, testes were at a position similar to those in controls. Furthermore, testicular descent was analyzed in relation to testicular weight, and we found that significantly smaller testes per gram of body weight than those of controls were at a significantly lower position compared to those of controls. Our data demonstrate that CGRP had no effect on postnatal testicular descent and that there is no relationship between postnatal descent and testicular weight.

A new technique for dynamic analysis of bladder compliance.

We propose an alternative method of measuring compliance that takes into account the multiple phases of bladder filling. We describe our new technique, dynamic compliance analysis, and evaluate its clinical applicability. To perform the analysis we digitized a cystometrogram curve at a sampling rate of 2 samples per second using an MS-DOS computer system. A program designed to retrieve the stored data was used to analyze the subtracted bladder pressure. The result yielded a value of compliance every half second that was then plotted on an x-y graph, with instantaneous compliance as the dependent variable and per cent of total volume infused as the independent variable. To determine the clinical applicability of this technique we chose 63 curves from clinically normal patients. The results of the dynamic compliance analyses were predictable. The dynamic compliance values for the normal group had a minimum that was always greater than 10 ml./cm. water throughout the tonus limb (phase 2) of the cystometrogram. We conclude that dynamic compliance analysis yields more information about bladder response during filling, similar to the stress-strain curve used in the study of solid mechanics.

What volume can a child normally store in the bladder at a safe pressure?

To determine what volume a child can normally store in the bladder at a safe pressure 923 pediatric urodynamic studies were reviewed, and 69 examinations done on 17 boys and 52 girls were considered normal. Patient ages were recorded and body surface areas were calculated. A continuous intermediate flow water cystometrogram had been performed. Total bladder capacity in milliliters, full resting pressures (cm. water), and the volumes (milliliters) and percentages of the total bladder capacity stored at detrusor pressures of less than 10, 20, 30 and 35 cm. water were measured. We found that 98.1% of the total bladder capacity could be stored at a detrusor pressure of less than 20 cm. water in more than 95% of the children independently of age or body surface area and 99.9% could be stored at a detrusor pressure of less than 30 cm. water. An approximation of the minimal acceptable total bladder capacity for age can be calculated by 16(age) + 70 in ml. According to our results, we proposed criteria for good storage characteristics of the bladder in children.

True hermaphrodites: an experimental model in the mouse.

When the Y chromosome from the Mus musculus domesticus mouse strain is placed onto the C57BL/6J mouse background ovarian and testicular components develop in half of the XY progeny (B6.YDOM), providing an excellent model of true hermaphroditism. We examined the correlation between gonadal sex and development of the internal genital tract in the B6.YDOM mouse at puberty. Of 55 mice examined 20 had bilateral testes, 33 were true hermaphrodites and 2 had mixed gonadal dysgenesis. In all mice with bilateral testes male accessory sexual organs developed bilaterally. In the true hermaphrodites testes were found on either side but preferentially on the left side. When a male feature was present on the ipsilateral side of the ovary, the seminal vesicle was more frequently found than prostate or vas. Testicular mass was significantly different between the true hermaphrodites with and those without bilateral seminal vesicles. Similar difference was found in those with and without bilateral prostates. The serum testosterone level was not significantly different between these groups. We conclude that the testicular mass is a better discriminant than serum testosterone for the presence or absence of seminal vesicles and prostates at puberty.

Extravesical nondismembered ureteroplasty with detrusorrhaphy: a renewed technique to correct vesicoureteral reflux in children.

We performed an extravesical nondismembered reimplant to correct surgically primary vesicoureteral reflux in 45 patients (65 renal units) between April 1989 and September 1990. Of the units 6 had grade I reflux, 16 grade II, 23 grade III, 14 grade IV and 6 grade V. Only patients with primary reflux were included in this study. The success rate was 100% for grades I to III, 92.9% for grade IV and 66.7% for grade V. Overall, the reflux was cured in 62 of the 65 operated renal units (95.4%) or 95.6% of the patients (43 of 45). Postoperative morbidity and complications were minimal. No cases of postoperative obstruction were detected on excretory urography 6 weeks postoperatively. Seven children (16%) suffered from transient inadequate bladder emptying as assessed by post-void ultrasound residual evaluations. This problem resolved spontaneously after a maximum of 4 weeks of clean intermittent catheterization. Compared to conventional transvesical technique, the discomfort related to bladder spasms during the postoperative period was subjectively decreased and patients had no prolonged hematuria.

Rapid development of an immunoblastic lymphoma and death in children following cadaveric renal transplantation.

We report on three children who underwent cadaveric renal transplantation and subsequently developed an immunoblastic lymphoma, leading to death in two patients. The development of the lymphoma occurred following a multi-drug immunosuppression regimen ending with monoclonal antilymphocyte (OKT3) treatment for biopsy-proven cellular and vascular acute rejection. These patients represent three of 11 children who received OKT3 treatment for rejection in the last 18 months at this institution. Following the diagnosis of lymphoma, all three patients were treated by transplant nephrectomy, cessation of immunosuppression, and administration of intravenous acyclovir. The first two patients died at 4 days and 4 weeks, respectively, after the definitive diagnosis was made with widespread metastatic disease. The remaining child is a short-term survivor (13 months), free of demonstrable malignancy. Multidrug regimens for immunosuppression have a profound effects on T cell function. These effects, when combined with a primary infection by the Epstein-Barr virus, are implicated in the rapid development of the lymphomas and are responsible for the death of these two children.

Effects of compound RU38486 on growth and lipid biosynthesis in glucocorticoid sensitive human leukemia line CEM-C7.

Glucocorticoid sensitive human lymphoblastoid cells CEM-C7 were examined for the effects of antiglucocorticoid RU38486 on the prevention of early dexamethasone-induced changes, including reduced cell growth, cell shrinkage and fragmentation, decrease in cell plating efficiency and incorporation of acetate into cellular lipids. When RU38486 was added no later than 24 hours after the addition of dexamethasone, it prevented the inhibition of [14C]acetate incorporation into nonsaponifiable lipids, partly reversed the decrease in plating efficiency and reduced cell fragmentation. In addition, the accumulation of dolichols in the nuclei of dexamethasone-treated cells was abolished by RU38486. These results indicate that glucocorticoid-induced changes in cellular lipids are receptor dependent and may be linked to the initiation of the apoptotic cascade.

Apoptosis: mode of cell death induced in T cell leukemia lines by dexamethasone and other agents.

Glucocorticoids can mediate the destruction of thymocytes and T cell-derived leukemia cells through a mechanism known as apoptosis. The characteristic feature of apoptosis is fragmentation of DNA at internucleosomal linkers through the activity of a specific endonuclease. In this study, an attempt was made to compare dexamethasone-induced apoptosis in two T cell-derived human leukemia lines (CEM-C1 and CEM-C7) to the cell killing brought about by selected cytotoxic agents. In the CEM-C7 cell line (dexamethasone-sensitive), apoptosis was induced not only by dexamethasone but by actinomycin D, cycloheximide, and 25-OH cholesterol. In the CEM-C1 cell line (dexamethasone-resistant) cycloheximide, 25-OH cholesterol, or cell starvation could induce apoptosis. It appears that in leukemic cells apoptosis may be induced by a variety of unrelated toxic agents and is not limited to glucocorticoids.

Emergency treatment and long-term follow-up of posterior urethral valves.

Posterior urethral valves have a broad spectrum of clinical severity determined by the degree and reversibility of the long stepwise sequence of secondary pathology. Neonatal azotemia and severe bilateral reflux are particularly important negative prognostic factors. In the mild cases, valve ablation with or without delayed reconstruction is good therapy. In the very severe cases, our interpretation of all the clinical and experimental information now available suggests that the time interval and the level of decompression are extremely important. Achievement of consistent low caliceal pressure without stasis and infections should be achieved as soon as possible. We do not agree with the philosophy of "valve ablation and wait and see" for secondary reconstruction as applied to the severe cases. An analogous philosophy would be treating all respiratory infections as upper respiratory infections and applying aggressive appropriate therapy for pneumonia only if the patient does not respond clinically. However, all controversy aside, the management of neonatal infants with posterior urethral valves remains a difficult and challenging problem for us all. The real challenge will be to improve published management results to the point that the family faced with decisions regarding an in utero diagnosis of posterior urethral valves will have enough hope to continue the pregnancy.

Dexamethasone-induced killing of neoplastic cells of lymphoid derivation: lack of early calcium involvement.

The role of calcium influx in dexamethasone-induced fragmentation of DNA was studied in the glucocorticoid-sensitive human lymphoid line of T cell derivation (CEM-C7). Reduction of calcium content in the medium or the use of EGTA increased DNA fragmentation and appeared to slightly enhance the effect of dexamethasone. Incubation of isolated nuclei in the presence of high concentrations of calcium did not bring about significant DNA fragmentation. Calmidazolium, an antagonist of calmodulin dependent reactions did not reduce the sensitivity of CEM-C7 cells to dexamethasone nor did it modify the response to dexamethasone of the resistant CEM-C1 line. It appears that in contrast to rodent thymocytes, massive calcium influx is not per se responsible for the initiation of directed cell killing (apoptosis).

Perioperative antibiotic prophylaxis for transurethral resection of the prostate: is it justifiable?

The role of perioperative antimicrobial prophylaxis in transurethral resection of the prostate remains controversial. A total of 110 patients with preoperative sterile urine undergoing transurethral resection of the prostate was included in this open, prospective and randomized study to compare the prophylactic role of cefoperazone to no antibiotic prophylaxis. Patients were well matched between the 2 groups on all essential characteristics and risk factors at baseline. Owing to the strict selection criteria and aseptic measures used, the low incidence of postoperative urinary tract infections in the control group (1.8 per cent) compared to none in the cefoperazone group made conclusions and generalization limited due to sample size. In view of the extremely low infection rate it is doubtful that antibiotic prophylaxis had any beneficial role in this selected population.