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Biomedical subjects

F Porchet

Publications and source records attributed to F Porchet.

At least 19 recordsLinked to original sources
PubMed2006

Interdisciplinary communication.

After an introduction clarifying the notion of interdisciplinarity, this chapter focuses on the importance of specific roles and mutual responsibilities within the interdisciplinary team, as well as basic rules of communication respecting the values of the concerned partners and professionals, as well as patient and family. Finally, the communication structure for efficient teamwork, and the importance of building a common vision, sharing leadership and learning to work together will be discussed.

Communication↗
PubMed2006

Cerebral vascular autoregulation assessed by perfusion-CT in severe head trauma patients.

PURPOSE: To use perfusion-CT technique in order to characterize cerebral vascular autoregulation in a population of severe head trauma patients with features of cerebral edema either on the admission or on the follow-up conventional noncontrast cerebral CT. MATERIAL AND METHODS: A total of 80 perfusion-CT examinations were obtained in 42 severe head trauma patients with features of cerebral edema on conventional noncontrast cerebral CT, either on admission or during follow-up. Perfusion-CT results, i.e. the regional cerebral blood volume (rCBV) and flow (rCBF), were correlated with the mean arterial pressure (MAP) measured during each perfusion-CT examination. Ratios were defined to integrate the concept of cerebral vascular autoregulation, and cluster analysis performed, which allowed identification of different subgroups of patients. MAP values and perfusion-CT results in these groups were compared using Kruskal-Wallis and Wilcoxon (Mann-Whitney) tests. Moreover, the functional outcome of the 42 patients was evaluated 3 months after trauma on the basis of the Glasgow Outcome Scale (GOS) score and similarly compared between groups. RESULTS: Three main groups of patients were identified: 1) 22 perfusion-CT examinations were collected in 13 patients, characterized by high rCBV and rCBF values and by significant dependence of perfusion-CT rCBV and rCBF results on MAP values (p<0.001), 2) 23 perfusion-CT examinations collected in 19 patients showing perfusion-CT results similar to control trauma subjects, and 3) 33 perfusion-CT collected in 16 patients, with low rCBV and rCBF values and near-independence of perfusion-CT results with respect to MAP values. The first group was interpreted as showing impaired cerebral vascular autoregulation, which was preserved in the third group. The second group was associated with the best functional outcome; it was linked to the first group, because eight patients went from one group to the other from admission to follow-up. CONCLUSION: Perfusion-CT in severe head trauma patients was able to provide direct and quantitative assessment of cerebral vascular autoregulation with a single measurement. It could hence be used as a guide for brain edema therapy, as well as to monitor the treatment efficiency.

Adult↗
PubMed2005

Early surgery for brainstem cavernomas.

BACKGROUND: The purpose was to review our experience with the surgical management of brainstem cavernomas (BSCs) and especially the impact of the surgical timing on the clinical outcome. METHOD: We retrospectively reviewed 22 patients harboring a BSC, who underwent 23 procedures. FINDINGS: Surgery was carried out during the early stage after the last haemorrhage, with a mean delay of 21.6 days (range 4-90 days). Sixteen procedures were performed after a first bleeding event while seven after multiple bleedings. Complete resection was achieved in 19 patients (86.4%). Early after surgery, 12 patients (52.2%) improved neurologically, 5 (21.7%) were stable and 6 (26.1%) worsened. New postoperative deficits were noted after 9 procedures (39.1%). Statistically significant factors for postoperative aggravation were: late surgery (P = 0.046) and multiple bleedings (P = 0.043). No patient operated on within the first 19 days after bleeding did worsen (n = 11), as opposed to 6 out of 12 who did when operated on later. After a mean follow-up of 44.9 months, 20 patients (90.9%) were improved, 1 patient (4.6%) was worse and 1 patient was lost to follow-up (4.6%), after reoperation for rebleeding of a previously completely resected cavernoma. Late morbidity was reduced to 8.6%. The mean Glasgow Outcome Scale (GOS) at the end of the follow-up period was 4.24, compared to a mean preoperative GOS of 3.22 (P<0.001). Complete neurological recovery of motor deficits, sensory disturbances, cranial nerves (CNs), internuclear ophtalmoplegia and cerebellar dysfunction were respectively 41.7%, 38.5%, 52.6%, 60.0% and 58.3%. Among the most affected CNs: CN 3, CN 5 and CN 7 were more prone to completely recover, respectively in 60.0%, 70.0% and 69.2%. CONCLUSIONS: Surgical removal of BSCs is feasible in experienced hands with acceptable morbidity and good outcome. Early surgery and single bleeding were associated with better surgical results.

Adolescent↗
PubMed2005

The role of posterior fossa decompression in acute cerebellitis.

BACKGROUND: We present two cases of children who were diagnosed with cerebellitis with acute cerebellar swelling. This rare pathology is potentially fatal, and no clear treatment guidelines are described in the literature. DISCUSSION: Considering our experience, we discuss the different therapeutic strategies and propose aggressive surgical measures consisting of external ventricular drainage and posterior fossa decompression in case of failure of early response to medical treatment to limit secondary cerebellar and brainstem lesions.

Acute Disease↗
PubMed2004

The origin of brain metastases in patients with an undiagnosed primary tumour.

BACKGROUND: In patients presenting brain metastases as the first manifestation of a previously undiagnosed primary tumour (UDP) histopathological confirmation of the diagnosis can be obtained by either direct surgical sampling of the brain lesion or paraclinical search for an accessible primary tumour. The sequence of the diagnostic work-up and the timing of an eventual neurosurgical intervention are a matter of debate and are mainly influenced by the distribution of primary tumours in UDP patients. The aim of this study was to verify the hypothesis that the distribution of primary tumours differs between UDP patients and the rest of the patients with brain metastases (DP), and to propose a diagnostic work-up specifically tailored to the UDP population. METHODS: Retrospective study on 342 patients admitted to the Lausanne University hospital between 1983 and 1998 with the diagnosis of cerebral metastases. FINDINGS: UDP patients represented 36% of the whole group. Primary tumour location was significantly different between the two groups (p=0.001). Although the lung was the most frequent primary tumour location in both groups (UDP: 60%, DP: 43%), in UDP 14% only of the primaries were found outside of the lung and as much as 26% remained unknown despite thorough investigations. CONCLUSIONS: Our study confirmed the hypothesis that the relative frequency of primary tumours differs between DP and UDP patients. This difference therefore mandates a diagnostic strategy specifically tailored for UDP patients: if a radiological lung investigation clearly remains the best initial step in the work-up of these patients, extensive paraclinical investigations without a clear clinical suspicion should probably not be undertaken if this first survey fails to disclose the primary tumour as only 14% of the patients will actually benefit from it. In this situation, a neurosurgical procedure should probably be considered the most appropriate next step to be taken in order to provide a definitive diagnosis without unnecessary delays.

Adult↗
PubMed2003

[Spinal tumors: clinical aspects, classification and surgical treatment].

Spinal tumors are classified in intradural and extradural tumors. Most extradural spinal tumors are metastasis. The other spinal tumors are rare and mostly benign. Only about 5% of tumors of the nervous system are spinal tumors. Their symptomatology is often insidious and the diagnosis can be difficult. Magnetic resonance imaging has revolutionized their diagnosis. The lesions within the spinal cord can now be directly visualized. The treatment of these tumors mostly require surgery. It has been proven that surgical results are better if these tumors are operated as soon as neurological symptoms have appeared. In our series of 39 operated intradural tumors we noted a functional improvement in 46.5% of the cases, a stabilisation in 43.5% and a deterioration in 10%.

Adolescent↗
PubMed2003

Spontaneous bilateral subdural haematomas in the posterior cranial fossa revealed by MRI.

A 52-year-old woman treated for acute myeloproliferative disease developed progressive stupor. CT showed obstructive hydrocephalus resulting from unexplained mass effect on the fourth ventricle. MRI revealed bilateral extra-axial collections in the posterior cranial fossa, giving high signal on T1- and T2-weighted images, suggesting subacute subdural haematomas. Subdural haematomas can be suspected on CT when there is unexplained mass effect. MRI may be essential to confirm the diagnosis and plan appropriate treatment.

Cranial Fossa, Posterior↗
PubMed2003

Current strategies in the management of spinal metastatic disease.

The treatment of metastatic spinal cord compression is complex. The three treatment modalities that are currently applied (in a histologically non-specific manner) are surgery, radiotherapy and the administration of steroids. The development of new spinal instrumentations and surgical approaches considerably changed the extent of therapeutic options in this field. These new surgical techniques have made it possible to resect these tumours totally, with subsequent vertebral reconstruction and spinal stabilization. In this respect, it is important to clearly identify those patients who can benefit from such an extensive surgery. We present our management algorithm to help select patients for surgery and at the same time identifying those for whom primary non-surgical therapy would be indicated. The retrospective review of surgically treated patients in our department in the last four years reveals a meagre application of conventional guidelines for the selection of the appropriate operative approach in the surgical management of these patients. The reasons for this discrepancy are discussed.

Algorithms↗
PubMed2001

[Role of surgical treatment of low back pain and lumbo-sciatica].

Low back pain alone without any sciatica is not an appropriate indication for lumbar disc surgery. The only exception might be a clinically and radiologically proven segmental instability. However a conservative multidisciplinary treatment should precede surgery. Good and excellent results of lumbar disc surgery are achieved in 80-90% of cases. The appropriate surgical indication and the postoperative reeducation are of utmost importance for good results. The patients history, neurological examination, neuroradiological imaging and failed conservative treatment modalities are key elements to define appropriate surgical candidates. Microdisectomy remains the "gold standard" for surgical treatment of lumbar disc disease assuring a better quality of life at long term follow up.

Humans↗
PubMed2001

Surgical treatment of lumbar spinal stenosis. Five-year follow-up.

We carried out a retrospective review of 155 patients with lumbar spinal stenosis who had been treated surgically and followed up regularly: 77 were evaluated at a mean of 6.5 years (5 to 8) after surgery by two independent observers. The outcome was assessed using the scoring system of Roland and Morris, and the rating system of Prolo, Oklund and Butcher. Instability was determined according to the criteria described by White and Panjabi. A significant decrease in low back pain and disability was seen. An excellent or good outcome was noted in 79% of patients; 9% showed secondary radiological instability. Surgical decompression is a safe and efficient procedure. In the absence of preoperative radiological evidence of instability, fusion is not required.

Adult↗
PubMed2000

Appropriateness of surgery for sciatica: reliability of guidelines from expert panels.

STUDY DESIGN: Reliability study of guidelines development. OBJECTIVE: To compare criteria for low back surgery between two expert panels. BACKGROUND: Reliability of expert panels for determining appropriateness of indications for surgical procedures has heretofore received little attention. METHODS: Two multidisciplinary expert panels of similar composition were convened, in the United States and in Switzerland, to evaluate the appropriateness of 720 distinct clinical scenarios involving sciatica. Each indication was assigned to a category of appropriate, uncertain, and inappropriate. The appropriateness of the 720 theoretical scenarios were compared between the two panels, and both sets of criteria were applied to two series of actual cases. RESULTS: Seventy-nine percent (n = 566) of the 720 theoretical indications were assigned to identical categories of appropriateness by both panels (kappa = 0.63; P < 0.001). Only 2 of the 720 scenarios elicited frank disagreement. The percentage of the 720 indications that were considered appropriate differed between the two panels (U.S.: 3%; Swiss: 11%, P < 0.001), as did the percentage of intrapanel agreement for indications (U.S.: 51%, Swiss: 64%, P < 0.001). When the same theoretical scenarios were matched with two series of actual cases (n = 181 and 149) agreement was moderate (kappa = 0.46) to fair (kappa = 0.30). CONCLUSION: There was substantial agreement on the appropriateness of surgery for theoretical cases of sciatica between independent expert panels from two countries. A better understanding of discordant ratings, especially for actual cases, should precede attempts at transposing recommendations emanating from a panel in one country to another.

Expert Testimony↗
PubMed2000

Cytochrome P-450 activities in human and rat brain microsomes.

The role of cytochrome P450 in the metabolism of dextromethorphan, amitriptyline, midazolam, S-mephenytoin, citalopram, fluoxetine and sertraline was investigated in rat and human brain microsomes. Depending on the parameters, the limit of quantification using gas chromatography-mass spectrometry methods was between 1.6 and 20 pmol per incubation, which generally contained 1500 microg protein. Amitriptyline was shown to be demethylated to nortriptyline by both rat and human microsomes. Inhibition studies using ketoconazole, furafylline, sulfaphenazole, omeprazole and quinidine suggested that CYP3A4 is the isoform responsible for this reaction whereas CYP1A2, CYP2C9, CYP2C19 and CYP2D6 do not seem to be involved. This result was confirmed by using a monoclonal antibody against CYP3A4. Dextromethorphan was metabolized to dextrorphan in rat brain microsomes and was inhibited by quinidine and by a polyclonal antibody against CYP2D6. Only the addition of exogenous reductase allowed the measurement of this activity in human brain microsomes. Metabolites of the other substrates could not be detected, possibly due to an insufficiently sensitive method. It is concluded that cytochrome P450 activity in the brain is very low, but that psychotropic drugs could undergo a local cerebral metabolism which could have pharmacological and/or toxicological consequences.

Aged↗
PubMed1999

Inhibition of epidural fibrosis with ADCON-L: effect on clinical outcome one year following re-operation for recurrent lumbar radiculopathy.

In a prospective multicenter study, 20 patients underwent re-operation for recurrent radiculopathy after lumbo-sacral discectomy, and were treated with ADCON-L (Adhesion Control in a Barrier Gel) to inhibit epidural fibrosis following secondary surgery. Outcomes after re-operation were assessed at six and 12 months using: Visual Analog Scales to measure radicular and back pain, straight leg raising exams, and self-assessment of activity-related radicular pain. Each parameter was compared to baseline values, obtained immediately prior to the re-operation. The long term clinical results at 12 months after re-operation (summarized below) demonstrate a significant improvement of all clinical parameters, and correlated with the results seen at six months. Radicular pain, measured when most severe, was reduced from an average pre-operative score of 8.1-3.7 (p < 0.005). The straight leg raising angle increased from an average pre-operative value of 41 degrees-67 degrees (p < 0.005). Activity-related pain mean score was 4.6, vs. 17.0 pre-operatively (p < 0.005). Low back pain, measured when most severe, was reduced from an average pre-operative score of 6.1 to 3.1 (p < 0.012). These clinical findings compare very favorably with data reported in the literature. There were no adverse events or complications related to the use of ADCON-L.

Adult↗
PubMed1999

Can the decision to operate be judged retrospectively? A study of medical records.

OBJECTIVE: To examine the precision and completeness of information in medical records for evaluating the appropriateness of operative indications for lumbar disc surgery. DESIGN: Retrospective review of records. SETTING: University department of neurosurgery, Switzerland. SUBJECT: 100 patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Proportion of pre-defined, detailed appropriateness criteria present in the records. Proportion of cases that could unequivocally be classified as to the appropriateness of the indication for operation. RESULTS: The criteria were present and precise for 52 of the items (range 9-90); present but imprecise for 38 of the items, and absent for 10. Because of this imprecision, the appropriateness of only 7 of the operative indications could be unequivocally assessed retrospectively. CONCLUSION: Medical records are of limited use in assessing the appropriate management of care. The process of care should therefore be evaluated prospectively.

Female↗
PubMed1999

Statistical approaches in the development of clinical practice guidelines from expert panels: the case of laminectomy in sciatica patients.

BACKGROUND: Variation in expert opinion and lack of a systematic methodology hinder the development of reliable clinical practice guidelines. However standardized protocols have been defined to quantify, combine, and summarize expert judgments. In addition, statistical methods may help to outline guidelines based on simplified models of these judgments. METHODS: To test this hypothesis, stepwise logistic regression (SLR) and classification tree pruning (CTP) were used to predict the results of two expert panels (USA 1992 and Switzerland 1995) on laminectomy in sciatica conditions. Both panels, using the RAND-UCLA explicit method, assessed whether the procedure would be inappropriate or of potential use in 720 case scenarios combining 7 relevant factors. RESULTS: Laminectomy was rated as inappropriate in 60% and 70% of the scenarios by the US and Swiss panels, respectively. Either statistical method, in both panels, based its simplest model on the same 4 factors, as follows: imaging test results; disability; neurological findings; and conservative treatment trials (in decreasing order); the influence of 2 other factors, duration of pain and nerve root irritation, were only marginal. The correct classification rates of the models were 89% and 93% for SLR and 93% and 85% for CTP. Adopting the CTP US algorithm as a guideline would lead to consider performing laminectomy only in patients with imaging evidence of hernia, relatively severe disability, reflex abnormalities, and previous nonsurgical treatment. Adherence to the corresponding CTP Swiss algorithm would result in less restrictive conditions. CONCLUSION: The statistical techniques proved as useful instruments to structure and simplify appropriateness criteria developed by expert panels and to outline parsimonious decision models for clinical practice.

Algorithms↗
PubMed1999

The assessment of appropriate indications for laminectomy.

We have developed criteria to determine the appropriate indications for lumbar laminectomy, using the standard procedure developed at the RAND corporation and the University of California at Los Angeles (RAND-UCLA). A panel of five surgeons and four physicians individually assessed 1000 hypothetical cases of sciatica, back pain only, symptoms of spinal stenosis, spondylolisthesis, miscellaneous indications or the need for repeat laminectomy. For the first round each member of the panel used a scale ranging from 1 (extremely inappropriate) to 9 (extremely appropriate). After discussion and condensation of the results into three categories laminectomy was considered appropriate in 11% of the 1000 theoretical scenarios, equivocal in 26% and inappropriate in 63%. There was some variation between the six categories of malalignment, but full agreement in 64% of the hypothetical cases. We applied these criteria retrospectively to the records of 196 patients who had had surgical treatment for herniated discs in one Swiss University hospital. We found that 48% of the operations were for appropriate indications, 29% for equivocal reasons and that 23% were inappropriate. The RAND-UCLA method is a feasible, useful and coherent approach to the study of the indications for laminectomy and related procedures, providing a number of important insights. Our conclusions now require validation by carefully designed prospective clinical trials, such as those which are used for new medical techniques.

Back Pain↗
PubMed1999

Long-term follow up of patients surgically treated by the far-lateral approach for foraminal and extraforaminal lumbar disc herniations.

OBJECT: This study was undertaken to evaluate the long-term benefit in 202 patients who were surgically treated via a microsurgical far-lateral approach for foraminal or extraforaminal lumbar disc herniations. METHODS: All patients underwent surgery at the authors' institute since 1987 and represented 6.5% of all lumbar spinal disc surgeries. There were 67 women and 135 men who ranged in age from 19 to 78 years (mean age 58 years). All patients had unilateral leg pain due to lumbar disc herniations into or lateral to the lateral interpedicular compartment. One patient underwent surgery at the L1-2 level, nine at L2-3, 48 at L3-4, 86 at L4-5, and 58 at the L5-S1 level. The mean follow-up period was 50 months (range 12-120 months). Outcome was defined as excellent (no pain), good (some back pain), fair (moderate radiculopathy), and poor (unchanged or worse) based on Macnab classification. Overall, excellent and good results were achieved in 62 (31%) and 85 (42%) patients, respectively, and fair and poor results in 40 (20%) and 15 (7%) patients, respectively. Of 11 recurrent disc herniations, four presented in an extreme-lateral position, five in a paramedian location, and two on the contralateral side. There were three minor complications related to surgery, seven general complications, and no case of spinal instability. CONCLUSIONS: The far-lateral approach is a safe, effective procedure that avoids the risk of secondary spinal instability.

Adult↗