Preoperative Imaging Features are Associated with Surgical Complications Following Carotid Body Tumor Resection.

BACKGROUND: Surgical resection remains the treatment of choice for carotid body tumors (CBTs). Although perioperative complications such as carotid artery injury and neurological deficits occur infrequently, they can be devastating. The aim of this study was to evaluate whether clinical factors or preoperative imaging findings can accurately predict perioperative complications. METHODS: Twenty CBTs were resected from 19 patients. Preoperative computed tomography (CT) and magnetic resonance imaging (MRI) of the neck were used to measure the degree of circumferential involvement of the CBT to the internal carotid artery (ICA), carotid artery narrowing, tumor length, tumor volume, and the distance from the tip of the C2 dens to the superior aspect of the CBT (dens-CBT). Operative reports and Shamblin classification (I-III) of each tumor were independently reviewed. Preoperative imaging features were compared to perioperative cranial nerve injury (CNI), rates of carotid artery injury, and major carotid artery repairs, as well as Shamblin classifications≥II. RESULTS: CNI was associated with a high-lying CBT (dens-CBT=1.8 vs. 2.9 cm, p<0.01). All four patients with CNI had a dens-CBT of <3 cm. Neither tumor length and tumor volume nor the involvement of the ICA (≥180° as measured by CT or MRI) was associated with CNI, carotid artery injury, major carotid artery repair, or Shamblin II or III classification. No carotid artery narrowing was observed in any of the cases. CONCLUSIONS: Preoperative measurement of the dens-CBT is helpful in identifying CBTs at risk for CNI after surgical resection.

The functional neuroanatomy of dystonia.

Dystonia is a neurological disorder characterized by involuntary twisting movements and postures. There are many different clinical manifestations, and many different causes. The neuroanatomical substrates for dystonia are only partly understood. Although the traditional view localizes dystonia to basal ganglia circuits, there is increasing recognition that this view is inadequate for accommodating a substantial portion of available clinical and experimental evidence. A model in which several brain regions play a role in a network better accommodates the evidence. This network model accommodates neuropathological and neuroimaging evidence that dystonia may be associated with abnormalities in multiple different brain regions. It also accommodates animal studies showing that dystonic movements arise with manipulations of different brain regions. It is consistent with neurophysiological evidence suggesting defects in neural inhibitory processes, sensorimotor integration, and maladaptive plasticity. Finally, it may explain neurosurgical experience showing that targeting the basal ganglia is effective only for certain subpopulations of dystonia. Most importantly, the network model provides many new and testable hypotheses with direct relevance for new treatment strategies that go beyond the basal ganglia. This article is part of a Special Issue entitled "Advances in dystonia".

Chasing "shadows": discovering the subtleties of sestamibi scans to facilitate minimally invasive parathyroidectomy.

BACKGROUND: With the advent of sestamibi scans, high-resolution ultrasonography (US), and intraoperative intact parathyroid hormone (PTH) measurements, minimally invasive parathyroidectomy (MIP) is considered the standard of care for patients with primary hyperparathyroidism (PHPT). Preoperative imaging, however, can be negative more than 20% of the time. METHODS: We chose to examine one surgeon's experience with patients who presented with PHPT and negative or indeterminate preoperative imaging from July 1993 to September 2009. A retrospective review of a parathyroid surgery database and patient records was conducted to collect the following information: patient age and sex; calcium and PTH levels; sestamibi and US results; and operative reports. Each sestamibi scan had been re-reviewed preoperatively by the surgeon with a nuclear medicine physician. The study cohort included patients with negative or indeterminate sestamibi results and a negative or no US report in which the surgeon was able to identify a "shadow" or subtlety on sestamibi and plan an MIP. RESULTS: A total of 126 patients had a negative or indeterminate sestamibi scan and a negative or no US report. "Shadows" or subtleties were found in 18 of 44 (41%) of the cases with a negative sestamibi and in 62 of 82 (76%) of cases with an indeterminate sestamibi scan. For these 80 cases a MIP was planned. In all, 7 of 80 (9%) were converted to a bilateral exploration. The remaining 46 patients underwent a planned bilateral exploration. Cure rates were comparable: 99% in the study group compared to 97% in the group who underwent a planned or converted bilateral exploration. CONCLUSIONS: With careful preoperative re-review of a negative or indeterminate sestamibi scan and the identification of subtleties in patients with a negative preoperative US scan, a successful MIP can be performed 91% of the time with a 98% cure rate.

The basal ganglia and cerebellum interact in the expression of dystonic movement.

Dystonia is a neurological disorder characterized by excessive involuntary muscle contractions that lead to twisting movements or abnormal posturing. Traditional views place responsibility for dystonia with dysfunction of basal ganglia circuits, yet recent evidence has pointed towards cerebellar circuits as well. In the current studies we used two strategies to explore the hypothesis that the expression of dystonic movements depends on influences from a motor network that includes both the basal ganglia and cerebellum. The first strategy was to evaluate the consequences of subthreshold lesions of the striatum in two different animal models where dystonic movements are thought to originate from abnormal cerebellar function. The second strategy employed microdialysis to search for changes in striatal dopamine release in these two animal models where the cerebellum has been already implicated. One of the animal models involved tottering mice, which exhibit paroxysmal dystonia due to an inherited defect affecting calcium channels. In keeping with prior results implicating the cerebellum in this model, surgical removal of the cerebellum eliminated their dystonic attacks. In contrast, subclinical lesions of the striatum with either 6-hydroxydopamine (6OHDA) or quinolinic acid (QA) exaggerated their dystonic attacks. Microdialysis of the striatum revealed dystonic attacks in tottering mice to be associated with a significant reduction in extracellular striatal dopamine. The other animal model involved the induction of dystonia via pharmacological excitation of the cerebellar cortex by local application of kainic acid in normal mice. In this model the site of stimulation determines the origin of dystonia in the cerebellum. However, subclinical striatal lesions with either 6OHDA or QA again exaggerated their generalized dystonia. When dystonic movements were triggered by pharmacological stimulation of the cerebellum, microdialysis revealed significant reductions in striatal dopamine release. These results demonstrate important functional relationships between cerebellar and basal ganglia circuits in two different animal models of dystonia. They suggest that expression of dystonic movements depends on influences from both basal ganglia and cerebellum in both models. These results support the hypothesis that dystonia may result from disruption of a motor network involving both the basal ganglia and cerebellum, rather than isolated dysfunction of only one motor system.

Colon cancer metastasis to the thyroid gland: report of a case with unique molecular profile.

A high index of suspicion is needed when a patient presents with thyroid mass in the settings of an advanced CRC. Secondary thyroid malignancy should be considered unless proven otherwise. reatment should be determined considering extent of CRC metastasis, patient's general condition, and presence of local symptoms.

Parathyroid surgery can be safely performed in a community hospital by experienced parathyroid surgeons: A retrospective cohort study.

BACKGROUND: There is ongoing debate about the effectiveness and safety of performing parathyroid surgery in low-volume community hospitals. STUDY DESIGN/METHODS: Cases performed at community hospital by a group of 4 parathyroid surgeons (group 1) were reviewed. Cure and complication rates were analyzed in light of outcomes of an expert endocrine surgeon from high-volume academic center (group 2) as point of reference. RESULTS: During the respective time periods, 204 patients met inclusion criteria in group1 and 218 patients in group 2. Patient characteristics, biochemical tests, and performed localizing studies (ultrasound and sestamibi scan) were comparable between the two groups. Pathological findings, including adenoma, double adenoma, hyperplasia, and cancer were comparable. Each had comparable cure rates (97% and 99%) (p < 0.18) and complication rates (1% and 1%) (p < 0.93) for group 1 and 2, respectively. CONCLUSION: Our results showed that experienced parathyroid surgeons will achieve comparable excellent outcomes of parathyroid surgery at both community and academic-based centers. As the field of endocrine surgery evolves and matures, producing young fellowship-trained endocrine surgeons, there will be growing need for expanding the niche of endocrine surgery into community-based hospital settings, which eventually will contribute to expanding and equalizing access to high-quality surgical care across urban and rural areas.

Minimizing shear and compressive stress during pancreaticojejunostomy: rationale of a new technical modification.

The failure of the pancreaticojejunal anastomosis remains an important and potentially lethal postoperative complication after pancreaticoduodenectomy. During the pancreaticojejunostomy, creation of compressive and shear forces during suture placement and knot tying may cause deformation of and cutting through the fragile pancreatic parenchyma. We sought to understand the mechanics of needle-pancreas interaction and make adjustments to our pancreaticojejunostomy technique so that the creation of shear and compressive stress could be minimized. We provide a detailed description, a mathematical model, and analysis of the outcomes of our new technical modifications.