Imaging in isolated sacral tuberculosis: a review of 15 cases

Objective. To review imaging studies of isolated involvement of the sacrum due to tuberculosis and determine the role of imaging in the diagnosis and management of these patients. Design and patients. A retrospective analysis of 15 cases of isolated sacral tuberculosis imaged with MR imaging was performed. The CT images were also reviewed where available, and the various lesion characteristics were identified. We also reviewed the medical records in an attempt to determine the impact of the imaging studies on the management of these patients. Results. Fifteen patients (5 male, 10 female) presented with symptoms of 3–15 months’ duration. Chronic localized backache with muscle spasm was the commonest presenting symptom; discharging sinuses with abscess formation was found in six patients, five of whom were children. MR imaging of the sacrum revealed a hypointense marrow signal on T1-weighted images and hyperintense signal on T2-weighted images in 14 of 15 patients, the S2 vertebra being always involved. CT revealed osteolytic changes in the sacrum in all the five patients in whom CT was performed. All patients showed marked clinical improvement within 1 year of anti-tuberculous chemotherapy. Conclusion. Isolated tuberculosis of the sacrum is uncommon but should be suspected in patients presenting with chronic low backache or children with discharging sinuses/abscesses and showing sacral destruction on CT or MR imaging. MR imaging can identify cases and enables early institution of anti- tuberculous chemotherapy. Received: 31 August 1999 Revision requested: 1 November 1999 Revision received: 27 March 2000 Accepted: 14 April 2000     

Differential effect of BMP4 on NIH/3T3 and C2C12 cells: implications for endochondral bone formation.

After intramuscular implantation, BMP4-expressing NIH/3T3 fibroblasts and BMP4-expressing C2C12 myoblasts can promote ectopic cartilage and bone formation. Fibroblasts tend to undergo chondrogenesis, whereas myoblasts primarily undergo osteogenesis. These results suggest that endochondral bone formation may involve different cell types, a finding that could have major implications for the tissue engineering of bone and cartilage. INTRODUCTION: The delivery of BMP4 through cell-based gene therapy can trigger ectopic endochondral bone formation in skeletal muscle. We hypothesized that, when stimulated with or transduced to express BMP4, different types of cells residing within skeletal muscle might participate in different stages of endochondral bone formation. MATERIALS AND METHODS: We compared the responses of a fibroblast cell line (NIH/3T3), a myoblast cell line (C2C12), primary fibroblasts, and primary myoblasts to BMP4 stimulation in vitro. We then transduced the four cell populations to express BMP4 and compared their ability to promote ectopic endochondral bone formation in skeletal muscle. RESULTS: Under the influence of BMP4 in vitro and in vivo, NIH/3T3 cells differentiated toward both chondrogenic and osteogenic lineages, whereas most C2C12 cells underwent primarily osteogenic differentiation. NIH/3T3 cells genetically modified to express BMP4 induced delayed but more robust cartilage formation than did genetically modified C2C12 cells, which promoted rapid ossification. These differences in terms of the timing and amount of cartilage and bone formation persisted even after we introduced a retrovirus encoding dominant negative Runx2 (DNRunx2) into the C2C12 cells, which interferes with the function of Runx2. Superior osteogenic potential was also displayed by the primary myoblasts in vitro and in vivo compared with the primary fibroblasts. The different proliferation abilities and differentiation potentials exhibited by these cells when influenced by BMP4 may at least partially explain the differing roles that BMP4-expressing myogenic cells and BMP4-expressing fibroblastic cells play in endochondral bone formation. CONCLUSIONS: Our findings suggest that the process of endochondral bone formation in skeletal muscle after delivery of BMP4 involves different cell types, including fibroblastic cells, which are more involved in the chondrogenic phases, and myoblastic cells, which are primarily involved in osteogenesis. These findings could have important implications for the development of tissue engineering applications focused on bone and cartilage repair.     

Laparoscopic totally extraperitoneal versus Lichtenstein herniorrhaphy: cost comparison at teaching hospitals

Laparoscopic hernia repair is safe and effective and may result in less postoperative pain and faster recuperation compared with traditional open hernia repairs. Controversy exists as to the increased cost associated with laparoscopic repairs. The purpose of this study was to quantify and compare the cost of the totally extraperitoneal (TEP) laparoscopic repair and the tension-free Lichtenstein repair at teaching hospitals. The records of consecutive TEP (n = 28) and Lichtenstein (n = 28) repairs performed at Parkland Memorial Hospital and Zale-Lipshy University Hospital were reviewed. A detailed cost analysis was performed. Total patient charge (5,509 US dollars vs. 3,999 US dollars) and total cost (2,861 US dollars vs. 2,009 US dollars) were higher for TEP versus Lichtenstein repairs, respectively (P < 0.05). Operative time and complications were similar for both groups. Return to full activity (15 vs. 34 days) was faster for TEP versus Lichtenstein repairs, respectively (P < 0.05). Of 9 patients in the TEP group who had previously undergone an open hernia repair, 8 (89%) preferred the laparoscopic approach. The laparoscopic TEP repair costs 852 US dollars more than the Lichtenstein repair. The TEP repair results in faster recuperation. Patient preference and faster recuperation may offset the increased cost associated with laparoscopic hernia repair.     

Pylorus-preserving Pancreaticoduodenectomy in the Treatment of Chronic Pancreatitis

The pylorus-preserving pancreaticoduodenectomy (PPPD) is an alternative to the standard Whipple resection in the treatment of chronic pancreatitis. The operation is safe and can be performed with a low mortality rate. The most common early complication is delayed gastric emptying, which occurs in 25% to 30% of patients, and generally results in longer hospital stays than the standard Whipple procedure. Follow-up studies show that both operations are equally effective in relieving pain in approximately 75% of selected patients. In the long term, the PPPD successfully preserves physiologic gastric emptying, but at the cost of a higher marginal ulceration rate. The purported nutritional advantages of the PPPD over the classic Whipple resection have not been clearly established. At present, the PPPD is the procedure of choice for patients with chronic pancreatitis requiring panceraticoduodenectomy. Based on available information, this recommendation appears to arise form the fact that the PPPD is less radical than the regular Whipple procedure, and some surgeons find it technically easier. Our experience fails to show a distinct superiority of the PPPD over the Whipple operation.     

Postoperative surveillance of differentiated thyroid carcinoma: a selective approach

This review was conducted to evaluate the selective use of 131I whole-body scanning (WBS) and radioablation (RA) after thyroidectomy for patients with differentiated thyroid carcinoma (DTC). A review of patients undergoing thyroidectomy for DTC between July 1, 1980 and December 31, 1999 was performed. Postoperative surveillance involved a selective RA protocol based on a modification of the AMES criteria (age, metastases, extent of cancer, size, and multifocality of tumor). Lower-risk patients were followed by yearly thyroglobulin (Tg) levels and physical examinations (PE) whereas higher-risk patients additionally underwent WBS and RA when appropriate. Three hundred forty-three patients were identified; of these 27 per cent had positive lymph nodes or metastatic disease at their initial operation. Two hundred thirteen (64%) patients underwent postoperative WBS with 174 (82%) requiring RA. One hundred thirty (36%) low-risk patients were followed with yearly Tg and PE that when abnormal led to WBS and RA. No additional patient morbidity or mortality resulted from this protocol. Factors identified during multivariate analyses as being predictive of occult metastasis and recurrence (P < 0.05) included tumor size and lymph node status. These data support a selective approach to the postoperative surveillance of DTC using Tg and PE to monitor low-risk patients and WBS for those with a higher risk of recurrence.     

Differentiation between classic and atypical meningiomas with use of diffusion tensor imaging

BACKGROUND AND PURPOSE:The differentiation between classic and atypical meningiomas may have implications in preoperative planning but may not be possible on the basis of conventional MR imaging. Our hypothesis was that classic and atypical meningiomas have different patterns of intratumoral water diffusion that will allow for differentiation between them.MATERIALS AND METHODS:Preoperative diffusion tensor imaging (DTI) was performed in 12 classic and 12 atypical meningiomas. Signal intensity of solid-enhancing tumor regions on diffusion-weighted trace images and apparent diffusion coefficient (ADC) and fractional anisotropy (FA) maps was assessed. Regions of interest (ROIs) were placed in solid-enhancing regions, peritumoral edema, and contralateral normal-appearing white matter (NAWM) to measure tensor metrics including major (λ₁), intermediate (λ₂) and minor eigenvalues (λ₃) and FA and ADC values. Distribution of tensor shapes within enhancing tumors was calculated for all tumors. Differences between classic and atypical meningiomas in tumor signal intensity, intratumoral and peritumoral tensor metrics, as well as tensor shapes distribution were statistically analyzed.RESULTS:A significantly greater proportion of atypical meningiomas were isointense and hypointense on ADC maps (P = .007). Classic meningiomas had significantly lower FA (P = .012), higher ADC (P = .011), greater λ₂ (P = .020) and λ₃ (P = .003). There was significantly more spherical diffusion in classic than in atypical meningiomas (P = .020). All diffusion tensor metrics for peritumoral edema of the 2 tumor groups did not differ.CONCLUSION:DTI showed that intratumoral microscopic water motion is less organized in classic than in atypical meningiomas. This feature may allow for noninvasive differentiation between classic and atypical meningiomas.

Meningiomas account for between 16% and 20% of primary intracranial tumors.¹ According to the World Health Organization (WHO) classification system, 78% of meningiomas are grade I, 20.4% are grade II, and 1.6% are grade III.² Grades II and III meningiomas are more aggressive than grade I meningiomas. Five-year recurrence rates are 12% for benign meningiomas and 41% for atypical meningiomas.² Initial extent of tumor resection and histologic grade are key determinants for recurrence.³ Therefore, prospectively identifying their histologic grades can be clinically beneficial in treatment planning. Although conventional MR imaging can provide detailed morphologic information of meningiomas, its value in the prediction of WHO grades is limited.⁴According to the WHO classification,⁵ classic meningiomas differ from atypical ones in their number of mitoses, cellularity, and nucleus-to-cytoplasm ratio (N/C ratio) as well as their histologic patterns. Complex microstructural barriers in brain tissue, such as white matter tracts, cell membranes, and capillary vessels result in a tendency for water molecules to diffuse with direction (anisotropic diffusion) rather than equally in all directions (isotropic diffusion). Isotropic diffusion-weighted imaging (DWI), which measures average magnitude of water motion in apparent diffusion coefficient (ADC), has shown controversial results for differentiating classic from atypical meningiomas.^6-8 In contrast to isotropic DWI, diffusion tensor imaging (DTI) provides information about magnitude and directionality of water diffusion⁹ and thus may be able to measure the differences in intratumoral diffusion anisotropy as a result of histologic differences between classic and atypical meningiomas. On the other hand, peritumoral edema associated with meningiomas, regardless of classic or atypical subtypes, has always been considered a purely vasogenic edema (ie, absence of tumor cell infiltration).^10,11Our first hypothesis was that intratumoral diffusion anisotropy is different between these 2 tumor types and that differences in diffusion anisotropy as detected by DTI allow differentiation between them. Our second hypothesis was that anisotropic diffusion measured in peritumoral edema with DTI will not be different between classic and atypical meningiomas.     

Circumumbilical pyloromyotomy in the era of minimally invasive surgery

Background/purpose

No studies have investigated the cosmetic outcome of current approaches to pyloromyotomy in infants with hypertrophic pyloric stenosis. The purpose of this study was to evaluate the final appearance of the scar in patients undergoing circumumbilical pyloromyotomy.

Methods

During a 16-year period, 86 infants underwent circumumbilical pyloromyotomy at our institution. A detailed questionnaire was created to document the family members' perceptions of the esthetic appearance of the scar. Data were collected by telephone interview and at clinic visit. In addition, cosmesis was assessed by 5 staff members who scored blindly the esthetic outcome of the scars with comparative photographs, using a categorical scale.

Results

Fifty-seven families were tracked by telephone contact. In the family questionnaire, 100% of families reported an excellent or good scar. Of these, forty-one (72%) were available for cosmetic assessment. Follow-up ranged between 5 months and 15 years (mean, 6 years). The panel members ranked the scar, on average, as excellent or good for 90% of the patients. No assessor stated that a scar was unacceptable. Intra- and interobserver agreement was 0.72 and 0.78, respectively.

Conclusions

Overall satisfaction with the cosmetic outcome of circumumbilical pyloromyotomy is very high.     

Brain mechanisms for reading words and pseudowords: an integrated approach

The present study tested two predictions of dual-process models of reading: (i) that the brain structures involved in sublexical phonological analysis and those involved in whole-word phonological access during reading are different; and (ii) that reading of meaningful items, by means of the addressed phonology process, is mediated by different brain structures than reading of meaningless letter strings. We obtained brain activation profiles using Magnetic Source Imaging and, in addition, pronunciation latencies during reading of: (i) exception words (primarily involving addressed phonology and having meaning), (ii) pseudohomophones (requiring assembled phonology and having meaning), and (iii) pseudowords (requiring assembled phonology but having no meaning). Reading of meaningful items entailed a high degree of activation of the left posterior middle temporal gyrus (MTGp) and mesial temporal lobe areas, whereas reading the meaningless pseudowords was associated with much reduced activation of these two regions. Reading of all three types of print resulted in activation of the posterior superior temporal gyrus (STGp), inferior parietal and basal temporal areas. In addition, pronunciation speed of exception words correlated significantly with the onset of activity in MTGp but not STGp, whereas the opposite was true for pseudohomophones and pseudowords. These findings are consistent with the existence of two different brain mechanisms that support phonological processing in word reading: one mechanism that subserves assembled phonology and depends on the posterior part of STGp, and a second mechanism that is responsible for pronouncing words with rare print-to-sound correspondences and does not necessarily involve this region but instead appears to depend on MTGp.     

Day surgery for laparoscopic repair of abdominal wall hernias

Laparoscopic repair of abdominal wall hernias is still a controversial and nongeneralized therapeutic option. The aim of this paper is to evaluate the results of laparoscopic surgery on abdominal wall hernias at a day-surgery unit and to describe our procedure protocol. Prospective analysis of 300 patients undergoing laparoscopic surgery for abdominal wall hernias was conducted: 260 preperitoneal and 40 intraperitoneal. The patients' clinical features, hernia type, intraoperative and postoperative complications, and follow-up are studied for both types of surgery. All the patients receiving surgery with extraperitoneal laparoscopy were completed as a day-surgical procedure with a rate of conversion to open surgery of 2.3%. Twelve (30%) of the 40 patients operated on for ventral hernias using intraperitoneal laparoscopy required hospitalization: five for perioperative complications and seven for pain (16%). There was no case of infection or mesh rejection. The recurrence rates were 0.78% (two cases) for the inguinal hernias and 2.5% (one case) for the ventral hernias. In conclusion, laparoscopic repair of abdominal wall hernias in a day-surgery setting is an efficient alternative to open surgery. Electronic Publication