Postoperative Metabolic Changes Research Articles

The thalamus in trigeminal neuralgia: structural and metabolic abnormalities, and influence on surgical response

BackgroundMedically-refractory trigeminal neuralgia (TN) can be treated successfully with operative intervention, but a significant proportion of patients are non-responders despite undergoing technically successful surgery. The thalamus is a key component of the trigeminal sensory pathway involved in transmitting facial pain, but the role of the thalamus in TN, and its influence on durability of pain relief after TN surgery, are relatively understudied. We aimed to test the hypothesis that variations in thalamic structure and metabolism are related to surgical non-response in TN.MethodsWe performed a longitudinal, peri-operative neuroimaging study of the thalamus in medically-refractory TN patients undergoing microvascular decompression or percutaneous balloon compression rhizotomy. Patients underwent structural MRI and MR spectroscopy scans pre-operatively and at 1-week following surgery, and were classified as responders or non-responders based on 1-year post-operative pain outcome. Thalamus volume, shape, and metabolite concentration (choline/creatine [Cho/Cr] and N-acetylaspartate/creatine [NAA/Cr]) were evaluated at baseline and 1-week, and compared between responders, non-responders, and healthy controls.ResultsTwenty healthy controls and 23 patients with medically-refractory TN treated surgically (17 responders, 6 non-responders) were included. Pre-operatively, TN patients as a group showed significantly larger thalamus volume contralateral to the side of facial pain. However, vertex-wise shape analysis showed significant contralateral thalamus volume reduction in non-responders compared to responders in an axially-oriented band spanning the outer thalamic circumference (peak p = 0.019). Further, while pre-operative thalamic metabolite concentrations did not differ between responders and non-responders, as early as 1-week after surgery, long-term non-responders showed a distinct decrease in contralateral thalamic Cho/Cr and NAA/Cr, irrespective of surgery type, which was not observed in responders.ConclusionsAtrophy of the contralateral thalamus is a consistent feature across patients with medically-refractory TN. Regional alterations in preoperative thalamic structure, and very early post-operative metabolic changes in the thalamus, both appear to influence the durability of pain relief after TN surgery.

Natural Postoperative Bone Metabolic Changes after Total Knee Arthroplasty Determined by Positron Emission Tomography Scans

Artificial joint replacement surgery is the orthopedic procedure of choice to relieve pain, correct joint deformities, and help patients resume everyday activities. However, the detailed mechanisms regulating peri-implant bone remodeling at the bone-prosthesis interface remain elusive. To address this gap in knowledge, we evaluated the natural postoperative course of bone metabolism by using [18F] NaF positron emission tomography (PET)/computed tomography in 57 patients (104 joints) who underwent asymptomatic total knee arthroplasty (TKA). First, we measured total tracer uptake around TKA to determine the total bone metabolism (TBM) and used the ischial tuberosity as the reference tissue for normalization of PET images. Second, we calculated the TBM ratio (TBMR) by dividing the TBM by tracer uptake in the reference tissue. A moderate increase in TBMR was observed 4 - 5 days after implantation, and its intensity reached the maximum on the seventh postoperative day. The TBMR showed no differences until 12 weeks, after which it decreased slowly and returned to the basal levels. The new parameter TBMR and the unique pattern of postoperative metabolic changes in the bone around the prosthesis may help set accurate interpretation criteria to diagnose complications such as loosening or infections.

Primary hyperparathyroidism: Dynamic postoperative metabolic changes.

Little is known about the natural changes in parathyroid function after successful parathyroid surgery for primary hyperparathyroidism. The association of intact parathyroid hormone (iPTH) and calcium (Ca) with "temporary hypoparathyroidism" and "hungry bone syndrome" (HBS) was evaluated. Potential risk factors for temporary hypoparathyroidism and HBS were evaluated by taking blood samples before surgery, intra-operatively, at postoperative day (POD) 1, at POD 5 to 7, in postoperative week (POW) 8 and in postoperative month (POM) 6. Of 425 patients, 43 (10.1%) had temporary hypoparathyroidism and 36 (8.5%) had HBS. The discriminative ability of iPTH and Ca on POD 1 for temporary hypoparathyroidism and HBS. Intact parathyroid hormone (IPTH) on POD 1 showed the highest discriminative ability for temporary hypoparathyroidism (C-index=0.952), but not for HBS. IPTH was helpful in diagnosing HBS between POD 5 and 7 (C-index=0.708). Extending the model by including Ca resulted in little improvement of the discriminative ability for temporary hypoparathyroidism (C-index=0.964) and a decreased discriminative ability for HBS (C-index=0.705). Normal parathyroid metabolism was documented in 139 (32.7%) patients on POD 1 and in 423 (99.5%) 6months postoperatively, while 2 (0.5%) patients had persistent hyperparathyroidism, one diagnosed between POD 5 and 7 and another at POW 8. No patients suffered from permanent hypoparathyroidism. The necessity for Ca and vitamin D3 substitution cannot be predicted with certainty before POD 5 to 7 without serial laboratory measurements. Based on the results, a routine 8-week course of Ca and vitamin D3 treatment seems reasonable and its necessity should be evaluated in a follow-up study.

Citation classics: Top 50 cited articles in bariatric and metabolic surgery

BackgroundThe number of times an article has been cited reflects its influence in a specific field. The aim of this study was to identify and characterize the most highly cited articles published on bariatric and metabolic surgery. MethodsThe 50 most frequently cited articles in bariatric and metabolic surgery were identified from the Scopus database in December 2013. ResultsThe median number of citations was 383.5 (range 275–2482). Most of the articles were published from 2000–2012 (n = 35), followed by 1990–1999 (n = 12), then before 1990 (n = 3). These citation classics came from 8 countries, with the majority originating from the United States (n = 34), followed by Sweden (n = 4) and Australia (n = 4). The 50 articles were published in 20 journals, led by New England Journal of Medicine (n = 9) and Annals of Surgery (n = 9). Only 10 of the articles were published in obesity-specific journals. The level of evidence of the 49 clinical publications and 1 animal study consisted of level I (n = 5), II (n = 11), III (n = 9), IV (n = 19), and V (n = 6). Meta-analyses were 16% of the total citations. Metabolic (n = 12) and survival (n = 6) effects of surgery were among the most common fields of study. ConclusionExtending from the early 1950s through the voluminous growth period of the early 2000s, the field of bariatric and metabolic surgery led to the emergence of many top-cited scientific articles. These articles have provided the scientific basis for the only currently effective treatment for severe obesity. Articles published in high-impact journals, innovative observational studies, meta-analyses, survival analyses, and research on postoperative metabolic changes are most likely to be cited in the field of bariatric surgery.

Maternal Ileal Interposition Surgery Confers Metabolic Improvements to Offspring Independent of Effects on Maternal Body Weight in UCD-T2DM Rats

Increasing numbers of people are undergoing bariatric surgery, of which approximately half are women in their childbearing years. However, information on the long-term effects of maternal bariatric surgery in their children is lacking. Furthermore, since bariatric surgery is performed to reduce body weight, clinical studies have not been able to differentiate between benefits to the child due to maternal body weight loss versus other maternal postoperative metabolic changes. Therefore, we used the University of California, Davis, type 2 diabetes mellitus (UCD-T2DM) rat model to test the hypothesis that maternal ileal interposition (IT) surgery would confer beneficial metabolic effects in offspring, independent of effects on maternal body weight. IT surgery was performed on 2-month-old prediabetic female UCD-T2DM rats. Females were bred 3 weeks after surgery, and male pups were studied longitudinally. Maternal IT surgery resulted in decreased body weight in offspring compared with sham offspring (P < 0.05). IT offspring exhibited improvements of glucose-stimulated insulin secretion and nutrient-stimulated glucagon-like peptide-2 (GLP-2) secretion (P < 0.05). Fasting plasma unconjugated bile acid concentrations were 4-fold lower in IT offspring compared with sham offspring at two months of age (P < 0.001). Overall, maternal IT surgery confers modest improvements of body weight and improves insulin secretion and nutrient-stimulated GLP-2 secretion in offspring in the UCD-T2DM rat model of type 2 diabetes, indicating that this is a useful model for investigating the weight-independent metabolic effects of maternal bariatric surgery.

Preoperative and postoperative 1H-MR spectroscopy changes in frontal deep white matter and the thalamus in idiopathic normal pressure hydrocephalus

BackgroundIn a previous study we found significantly decreased N-acetyl aspartate (NAA) and total N-acetyl (tNA) groups in the thalamus of patients with idiopathic normal pressure hydrocephalus (iNPH) compared with healthy...

Cerebral microdialysis and positron emission tomography after surgery for aneurysmal subarachnoid hemorrhage in grade I patients

Background Using cerebral microdialysis, baseline values for energy-related chemical markers have been reported in awake patients. Radionuclide studies have demonstrated a locally decreased metabolism, thought to be the result of brain retraction. These baseline values, however, may not be applicable to patients after surgical aneurysm repair following a subarachnoid hemorrhage (SAH). We assessed metabolic chemical marker levels in World Federation of Neurological Surgeons Committee (WFNS) grade I SAH patients after aneurysm surgery and compared them with previously reported baseline values. Methods In 5 WFNS grade I SAH patients, energy-related chemical marker levels were obtained using microdialysis in the area of brain retraction after aneurysm surgery. In addition, an [ 18F]2-deoxy- d-glucose positron emission tomography (FDG-PET) was performed. Results The FDG-PET showed a decrease of glucose metabolism in the frontotemporal area. Comparing the mean values for chemical markers of this study with reported baseline values, the most striking difference was a mild decrease of pyruvate and an increase of the lactate/pyruvate ratio. In individual patients, some markers indicated possible ischemia. A consistent pattern or ischemic profile for all markers, however, was not found. Conclusion FDG-PET scanning confirmed postoperative metabolic changes found in previous studies. Mean interstitial chemical marker levels ranged from normal to mildly deviant compared with reference chemical marker levels for awake patients and are likely to be applicable in SAH patients after aneurysm repair.

Parenteral nutrition for the surgical patient. A review of indications and current practice.

Parenteral nutrition for the surgical patient. A review of indications and current practice.

POSTOPERATIVE METABOLIC CHANGES: IN RELATION TO NUTRITIONAL REGIMEN

POSTOPERATIVE METABOLIC CHANGES: IN RELATION TO NUTRITIONAL REGIMEN

The relationship of aldosterone excretion to the metabolic response to adrenalectomy

1. 1. Observations have been made on the balance of sodium, potassium, chloride and nitrogen, and the urinary excretion of corticosteroids and aldosterone in three patients undergoing, respectively, 1st stage adrenalectomy, 2nd stage adrenalectomy and ovariectomy after previous bilateral adrenalectomy. 2. 2. Post-operative metabolic changes of sodium and chloride retention with urinary loss of potassium and nitrogen occurred. In the patient subjected to 1st stage adrenalectomy, the metabolic response was accompanied by rises in the urinary excretion of aldosterone and total corticosteroids. In the patient undergoing 2nd-stage adrenalectomy and in the patient undergoing ovariectomy, the metabolic response was not associated with any rise in urinary corticosteroids, and urinary aldosterone was not detectable post-operatively. 3. 3. It is concluded that the metabolic responses ordinarily observed affecting sodium, potassium and nitrogen excretion after surgery can occur without concomitant rises in excretion of aldosterone.

The metabolic response to adrenalectomy and hypophysectomy

1. 1. Observations have been made upon the balance of sodium, potassium, chloride and nitrogen and the excretion of corticosteroids in the urine in three patients subjected to bilateral adrenalectomy and given constant doses of cortisone acetate, and in two patients undergoing hypophysectomy, only one of whom received cortisone acetate. 2. 2. The usual post-operative metabolic changes of sodium and chloride retention with loss of potassium and nitrogen in the urine occurred in all patients. In the three patients subjected to second stage adrenalectomy, the metabolic response was not associated with a rise in the urinary excretion of adrenocorticosteroids (acid-stable formaldehydogenic or 17-hydroxy-steroids). Increase in urinary corticosteroids occurred in both patients after hypophysectomy and in the one patient studied on whom a first stage adrenalectomy was performed. 3. 3. It is concluded that the metabolic responses observed after second stage adrenalectomy occurred in the absence of significant alterations in the rate of adrenocortical secretion. The observations we have made do not eliminate the possibility that trauma and surgical operation in patients with intact adrenal glands increase the secretory activity of the adrenal cortex. However the occurrence of alterations in electrolyte and nitrogen balance following surgical trauma may not be used as evidence that such an increase in secretion occurs. 4. 4. The role of the cortisone acetate given to the patients before and after removal of the adrenal glands in the metabolic response is discussed. Although the results are not inconsistent with the “permissive” action of the hormone as suggested by Ingle, the possibility that alterations in metabolism and the rate of excretion of the hormone result in an increase in the blood concentration of biologically effective hormone with consequent alterations in electrolyte and nitrogen balance cannot be excluded. Nevertheless, if such an alteration in the rate of disposal of biologically active hormone occurs for some days after the operation, it must do so without causing a rise in the urinary content of the measured steroid métabolites such as is normally found after operations not involving the adrenal glands. 5. 5. Four possible interpretations of the increase in corticosteroids in the urine after hypophysectomy are suggested but it is not possible to decide which of these explanations is correct.