16 March 2006

Ossur Scientific E-letter, Issue #1 2006

Dear readers,
The first issue of the Ossur Scientific E-letter of 2006 includes five different scientific papers related to the field of the treatment of amputees. The articles cover the subjects of amputation, postoperative treatment, rehabilitation, prosthetics/biomechanics and quality management. Three of the selected papers have been published in 2005 and two 2006.

Enjoy the reading!

Amputation

Use of a Pneumatic Tourniquet Improves outcome Following a Trans-tibial Amputation
Wolthuis A.M. Whitehead E. Ridler B.M.F. Cowan A.R. Campbell W.B. Thompson J.F.
European Journal of Vascular and Endovascular Surgery Article in Press, Corrected Proof Accepted 18 November 2005. Available online 19 January 2006.

Wolthus and colleagues aimed to assess their hypothesis that a tourniquet used during trans-tibial amputation would reduce blood loss and subsequent complications without risking the healing. Pneumatic Tourniquets are traditionally contraindicated for that amputation in patients with peripheral arterial disease. However they are used successfully during at arthroplasty in an elderly patient group. Wolthus et al wanted to explore if the use of pneumatic tourniquet altered the rates of wound complications, haemoglobin concentration, blood transfusions, revision, morbidity and deaths.

89 patients underwent a trans-tibial amputation between January 2001 and December 2003 and were included in this prospective non-randomized study. The patients were divided in one group with a pneumatic tourniquet (42 patients) and one without (47 patients). All patients had end stage peripheral vascular disease.

It was found that there were no complications associated with the use of the tourniquet; neither no deep vein thrombosis nor acute postoperative skin flap necrosis. The haemoglobin fall was significant lower in the tourniquet group (5,6%) than in the non-tourniquet group (14,8%). Also the difference in blood transfusion was significant; one single patient was transfused two units of packed cells in the tourniquet group compared to 20 patients (42,6%) transfused 47 units in the non-tourniquet group.

The postoperative morbidity rates were similar in the two groups.

Significant differences were found between the groups regarding stump revision. In the tourniquet group six patients (14,3%) underwent revision and five of them went on to femoral amputation (11,9%). 18 patients (38,3%) in the non-tourniquet group needed a stump revision and half of them (19,2%) required a amputation above the knee.

The differences of the blood transfusion rate and revision rates were of such level that the advantages of the pneumatic tourniquet appeared clear, but a randomised trial would support that impression.

The authors concluded that it is safe and gives significant benefits regarding blood loss and the need of transfusion to use a pneumatic tourniquet during trans-tibial amputations.

Postoperative

Stump management after trans-tibial amputation: A systematic review
Nawijn S. E. van der Linde H. Emmelot C. H. Hofstad C. J.
Prosthet Orthot Int. 2005 Apr;29(1):3-12.

The lack of consensus on how to use wound dressings to optimise the healing after trans-tibial amputation had Nawijn et al to perform a systematic literature review to identify the optimal post-amputation management.

The lack of consensus on how to use wound dressings to optimise the healing after trans-tibial amputation had Nawijn et al to perform a systematic literature review to identify the optimal post-amputation management.

The authors included 11 studies in the review. The selection was based on the methodological quality of the studies and following criteria's:
1. "Studies that pertained to post-surgical stump dressings or the use of temporary prostheses in trans-tibial amputees.
2. Studies in which wound healing after amputation, oedema control or mobilization were the outcome measures.
3. Studies with either a Randomized Controlled Trial (RCT) design or a case-control design.
4. Publication in the English, German, French, or Dutch language".

Nawijn and colleagues found a trend in favour of the application of rigid and semi-rigid dressings compared to the application of soft dressings in order to achieve stump healing and reduction of stump volume in trans-tibial amputations due to peripheral vascular disease. It was also found support for a shorter time to prosthetic fitting in the studied patient groups treated with semi rigid dressing compared to patients treated with soft dressing. The functional outcome was more unclear; some studies reported a higher amount of patients becoming ambulatory when treated with semi rigid dressing compared to soft dressing, other did not find differences in functional outcome between the groups. A reduced time between amputation to gait training was reported in a study comparing plaster dressing to elastic bandage.

Rehabilitation

Phantom Pain, Residual Limb Pain, and Back Pain in Amputees: Results of a National Survey
Ephraim PE, Wegener ST, MacKenzie EJ, Dillingham TR, Pezzin LE
Archives of Physical Medicine and Rehabilitation Volume 86, Issue 10 , October 2005, Pages 1910-1919

Ephraim et al performed a cross sectional survey of amputees to illustrate the prevalence of pain related to amputation, to determine the intensity and affective quality of phantom pain, residual limb pain, back pain, nonamputated limb pain and to identify the relationship between demographic variables, amputation related factors, depressed mood and the experience of pain of the amputated persons.

The sample of 914 persons was telephone interviewed.

Almost all amputees (95%) included in the study experienced one or more types of pain related to the amputation, regardless of time since amputation. The result showed that in the study group experienced 79,9% phantom pain, 67,7% residual limb pain and 62,3 % back pain. Many of the persons with phantom pain and stump pain found their problems severe. A quarter of those experiencing amputation related pain found it to be extremely bothersome. Risk factors for bothersomeness and amputation related pain varied by pain site. However, across all pain types, depressive symptoms showed to be a significant risk of intensity and bothersomeness of pain.
No statistically significant correlations were found between phantom pain, age or level of amputation.

The authors suggest interventions to rehabilitate and improve the overall quality of life among persons with limb loss. That would reduce both the amount and the quality of pain and depression among amputees.

Prosthetics/biomechanics

Regional differences in pain threshold and tolerance of the transtibial residual limb: Including the effects of age and interface material
Lee WC, Zhang M, Mak AF (2005)
Archives of Physical Medicine and Rehabilitation Volume 86, Issue 4 , April 2005, Pages 641-649

Comfort is shown to be one of the most important factors when using prosthesis. This article contributes to the understanding of the reactions to load transfer between the prosthesis and the residual limb. Lee, Zhang and Mak wanted to compare the minimum pressure inducing pain and the maximal tolerable pressure of different sites of the residual limb. They also sought after to assess the interface pressure distribution and distortion of the skin surface on indentation by finite element (FE) analysis. Eight trans-tibial amputees were included for the indentation test and one for the FE analysis.

The loads were applied to the residual limb by an intender attached to a force transducer. The load was increased until the test subject could not tolerate it longer. To simulate the indentation process, with the recorded pain threshold, a FE model was built.

It was surprisingly found that some areas with thicker soft tissue layer had lower pain tolerance and thresholds than areas with thinner layers of soft tissue. Further it was showed that the patellar tendon was best and the distal end of the fibula the worst load tolerant areas. Aging seemed to affect the pain tolerance and threshold towards less tolerance and a lower threshold. The FE model suggests, when the pressure is exceeding a certain level, the pain is triggered.

Quality management

How trial designs impact on guidelines?
French J A.
Epilepsy Research Volume 68, Issue 1 , January 2006, Pages 56-60

Evidence based guidelines and practice parameters have been developed in most areas of medicine. Those guidelines have to be based on evidence proved in scientific studies. French have described how clinical trials should be designed so they will be considered to provide a high level of evidence. "Understanding the variables that will be considered for treatment guidelines can improve the methodological strength of studies and lead to recommendations for practice".

A development of a guideline is initiated by selecting the topic. That is usually based on the clinical importance of the topic, whether it is a gap between current clinical practice and the available evidence, whether there is controversy about what is best practice and whether there is sufficient evidence available to make a contribution.

The next step in developing guideline is to select a team with the attempt to be multidisciplinary, to bring in all viewpoints to minimize bias. The team defines a question that is clinically focused and answerable. It should include three basic components; the population involved, the intervention and the addressed outcome. When the question is defined the team search the literature for information. Usually only peer reviewed literature should be used. Every step in the literature search must be documented and reported in the guideline. The selection of articles to be included in the guideline must have been done by systematic selection criteria. Those criteria are used to classify the evidence of articles to be included. The strengths of the evidence in the articles determine the recommendation in the guideline.

The presence of randomization, control group, using masked outcome assessment, using an adequate comparator and adequate enrolment in active-controlled trials to detect a difference if one exists, will be assessed. Variables that also must be addressed are a clear priori definition of the primary outcome variable, clearly defined inclusion/exclusion criteria, presence of equivalent treatment groups at baseline, adequate duration of assessment to answer the clinical question, and appropriate management and statistical handling of drop-outs.

The author concludes that studies that will lead to recommendations for practice has to be strong and performed with a good methodology.

The development of treatment guidelines based on high quality trials will benefit the population for whom the therapeutic intervention have been tested for, the personal working with it and the investigator and it's sponsor.

Empower Health Care Solutions wish you all the best for the spring and is looking forward to provide you interesting scientific news in May 2006!

Best regards,
Louise Klevbo