Aziz Nather

Epidemiology of diabetic foot problems and predictive factors for limb loss

OBJECTIVES The aim of this study was to evaluate the epidemiology of diabetic foot problems (DFP) and predictive factors for major amputations (below- and above-knee). METHODS This is a prospective study of 202 patients treated in National University Hospital (NUH) during the period of January 2005 to May 2006. A protocol was designed for documentation including patient profile, type of DFP, presence of risk factors, comorbidities and complications, clinical presentation, investigations, treatment given, and final outcome. The predictors for limb loss were determined using univariate and stepwise logistic regression analysis. RESULTS One hundred ninety-two patients had Type 2 diabetes. Mean age of cohort was 60 years, with male to female ratio of 1:1. Incidence of DFP was significantly higher in Malays (P=.0015) and Indians (P=.036) and significantly lower in Chinese (P<.05). Of patients, 72.8% had poor endocrine control (GHb level >7%), and 42.1% of patients had sensory neuropathy based on 5.07 Semmes-Weinstein Monofilament test. Common DFP included gangrene (31.7%), infection (abscess, osteomyelitis) (28.7%), ulcer (27.7%), cellulitis (6.4%), necrotizing fasciitis (3.5%) and Charcots osteoarthropathy (2.0%). Surgery was performed in 74.8% of patients and major amputation in 27.2% of patients (below-knee in 20.3% and above-knee in 6.9%). CONCLUSIONS This is the first detailed prospective study evaluating predictive factors for major amputations in patients with DFP. Significant univariate predictive factors for limb loss were age above 60 years, stroke, ischaemic heart disease, nephropathy, peripheral vascular disease (PVD), sensory neuropathy, glycosylated haemoglobin level, Ankle Brachial Index (ABI) <0.8, gangrene, infection, and pathogens such as methicillin-resistant Streptococcus aureus (MRSA) and Staphylococcus aereus. Upon stepwise logistic regression analysis, only PVD and infection were significant.

Assessment of sensory neuropathy in diabetic patients without diabetic foot problems.

OBJECTIVES To study the incidence and extent of peripheral sensory neuropathy in diabetic patients without diabetic foot problems (DFPs) with <5, 5-10 and >10 years duration of diabetes using three different modalities of testing: Pin-Prick Testing, 5.07 Semmes-Weinstein Monofilament Testing (SWMT) and Rapid-Current Perception Threshold (R-CPT) measurements using the Neurometer. METHODS Our study population consisted of 60 patients (120 feet) treated for diabetes mellitus in the Division of Endocrinology at the National University Hospital. No patient had any DFPs. Twenty-two, 21 and 17 patients had duration of diabetes of <5, 5-10 and >10 years, respectively. All patients were tested for sensory neuropathy using Pin-Prick Testing using a standardized protocol, SWMT and the Neurometer. RESULTS There was a significantly higher incidence of sensory neuropathy detected by both the Pin-Prick Test and the Neurometer as compared to the SWMT. Also, in all three modalities, there was a significant increase in incidence of sensory neuropathy detected in diabetics with >5 years duration of diabetes. In addition, the Pin-Prick Test showed an increase in extent of sensory neuropathy with a longer duration of diabetes. CONCLUSIONS The Pin-Prick Test was found to be a simple, cheap and useful diagnostic tool for detection of sensory neuropathy in diabetics without DFPs. In addition, it could accurately delineate the extent of neuropathy in the lower limb - additional useful information not obtainable with SWMT or Neurometer. Even for patients with <5 years duration of diabetes, the incidence of sensory neuropathy detected was considerable. The incidence of neuropathy detected continued to increase with length of duration of diabetes. Hence, we recommend screening of patients for neuropathy as soon as they are diagnosed with diabetes.

Negative-pressure wound therapy for management of diabetic foot wounds: a review of the mechanism of action, clinical applications, and recent developments

Negative-pressure wound therapy (NPWT) plays an important role in the treatment of complex wounds. Its effect on limb salvage in the management of the diabetic foot is well described in the literature. However, a successful outcome in this subgroup of diabetic patients requires a multidisciplinary approach with careful patient selection, appropriate surgical debridement, targeted antibiotic therapy, and optimization of healing markers. Evolving NPWT technology including instillation therapy, nanocrystalline adjuncts, and portable systems can further improve results if used with correct indications. This review article summarizes current knowledge about the role of NPWT in the management of the diabetic foot and its mode of action, clinical applications, and recent developments.

Predictive factors for lower extremity amputations in diabetic foot infections

The objective of this study was to evaluate the epidemiology of diabetic foot infections (DFIs) and its predictive factors for lower extremity amputations. A prospective study of 100 patients with DFIs treated at the National University Hospital of Singapore were recruited in the study during the period of January 2005–June 2005. A protocol was designed to document patients demographics, type of DFI, presence of neuropathy and/or vasculopathy and its final outcome. Predictive factors for limb loss were determined using univariate and stepwise logistic regression analysis. The mean age of the study population was 59.8 years with a male to female ratio of about 1:1 and with a mean follow-up duration of about 24 months. All patients had type 2 diabetes mellitus. Common DFIs included abscess (32%), wet gangrene (29%), infected ulcers (19%), osteomyelitis (13%), necrotizing fasciitis (4%) and cellulitis (3%). Thirteen patients were treated conservatively, while surgical debridement or distal amputation was performed in 59 patients. Twenty-eight patients had major amputations (below or above knee) performed. Forty-eight percent had monomicrobial infections compared with 52% with polymicrobial infections. The most common pathogens found in all infections (both monomicrobial and polymicrobial) were Staphylococcus aureus (39.7%), Bacteroides fragilis (30.3%), Pseudomonas aeruginosa (26.0%) and Streptococcus agalactiae (21.0%). Significant univariate predictive factors for limb loss included age above 60 years, gangrene, ankle-brachial index (ABI) <0.8, monomicrobial infections, white blood cell (WBC) count ≥ 15.0×109/L, erythrocyte sedimentation rate ≥100 mm/hr, C-reactive protein ≥15.0 mg/dL, hemoglobin (Hb) ≤10.0g/dL and creatinine ≥150 µmol/L. Upon stepwise logistic regression, only gangrene, ABI <0.8, WBC ≥ 15.0×109/L and Hb ≤10.0g/dL were significant.

Diabetic Foot Problems

Diabetes and Its Complications: A Global Problem (A Lim) Team Approach for Diabetic Foot Problems (A Nather et al.) Foot at Risk (A Jorgensen) Assessment for Neuropathy (A Nather) Outpatient Management (S B Chionh) Antibiotics in Management of Diabetic Foot Infections (P A Tambyah) Necrotizing Fasciitis (C H Wong) Role of Angiography and MRA (P Robless) Role of Vascular Surgery for Revascularization of Diabetic Foot (M G Sebastian) Predictive Factors for Limb Salvage: Singapore Experience (A Nather) Major Amputations (B Tiksnadi) Rehabilitation for Amputees (M Soedirman) Phantom Pain and Its Management (W Kusumaningsih) Surgery for Charcots Osteoarthropathy (I Singh) Role of Hyperbaric Oxygen (K Chan) Use of Phytochemicals for Infected Diabetic Foot Ulcers (S Sivananthan) Role of Anodyne Therapy (A Nather & E Sim) Role of Laser (P Hassan) Vacuum Pressings (A Lim) Principles of Skin Coverings for the Foot (J W-Y Ip) Screening Feet for All Diabetics (A Nather et al.) Footcare (A Erasmus) The Role of Stem Cells for Treatment of Diabetic Foot Problems (B Setiawan) The Role of Stem Cells for Limb Ischemia (S Cornain) and other chapters.

Value of team approach combined with clinical pathway for diabetic foot problems: a clinical evaluation.

Aims : To evaluate the effectiveness of management of diabetic foot problems (DFP) by the National University Hospital (NUH) Multidisciplinary Diabetic Foot Team combined with a clinical pathway in terms of average length of stay (ALOS), readmission rates, hospitalisation cost per patient, major reamputation rate, and complication rate. Methods : 939 patients admitted to the Department of Orthopaedic Surgery, NUH, for DFP from 2002 (before team formation) to 2007 (after team formation). It consisted of six cohorts of patients – 61 for 2002, 70 for 2003, 148 for 2004, 180 for 2005, 262 for 2006, and 218 for 2007. All patients were managed by the NUH Multidisciplinary Diabetic Foot Team combined with a clinical pathway. Statistical analyses were carried out for five parameters (ALOS, hospitalisation cost per patient, major amputation rate, readmission rate, and complication rate). Results : From 2002 to 2007, the ALOS was significantly reduced from 20.36 days to 12.20 days (p=0.0005). Major amputation rate was significantly reduced from 31.15 to 11.01% (p<0.0005). There was also a significant reduction in complication rate from 19.67 to 7.34% (p=0.005). There were reductions in the hospitalisation cost per patient and readmission rate after formation of the multidisciplinary team but they were not statistically significant. Conclusion : Our evaluation showed that a multidisciplinary team approach combined with the implementation of a clinical pathway in NUH was effective in reducing the ALOS, major amputation rate, and complication rate of DFP.

Distal amputations for the diabetic foot

Minor amputations in diabetic patients with foot complications have been well studied in the literature but controversy still remains as to what constitutes successful or non-successful limb salvage. In addition, there is a lack of consensus on the definition of a minor or distal amputation and a major or proximal amputation for the diabetic population. In this article, the authors review the existing literature to evaluate the efficacy of minor amputations in this selected group of patients in terms of diabetic limb salvage and also propose several definitions regarding diabetic foot amputations.

Allografts with autogenous platelet-rich plasma for tibial defect reconstruction: a rabbit study

Purpose. To evaluate the effect of autogenous platelet-rich plasma (PRP) for fresh-frozen allografts in tibial defect reconstruction in rabbits. Methods. 40 adult New Zealand white rabbits underwent tibial defect reconstruction with autografts (n=12), allografts without PRP (n=12), or allografts with PRP (n=12) and were observed for 12, 16, and 24 weeks (4 for each period). Tibias of the remaining 4 rabbits were used as donor allografts, and the remaining allografts were procured from recipient rabbits. A 1.5-cm cortical segment of the tibia was osteotomised, and then fixed with a 9-hole mini-compression plate and 2 cerclage wires. Allografts were stripped off the periosteum and soft tissues and medullary contents, and then stored in a freezer at −80°C. All allografts were deep frozen for at least 4 weeks before transplantation. 7 ml of whole blood was drawn to prepare 1 ml of PRP. The PRP was then mixed with 1.0 ml of human thrombin to form a platelet gel. The PRP gel was then packed into the medullary canal of the allograft and applied on the cortical surface before tibial defect reconstruction. Rabbits were sacrificed at 12, 16, and 24 weeks. The specimens were assessed for bone union at host-graft junctions and for bone resorption, new bone formation, callus encasement, and viable osteocyte counts. Results. There were 4 specimens in each group at each observation period. Osteoid bridging the gap at host-graft junctions was noted in all specimens in the autograft and allograft-with-PRP groups at week 12 and in the allograft-without-PRP group at week 24. Bone union in allografts without PRP was delayed. All indices for biological incorporation (resorption index, new bone formation index, callus encasement index, and viable osteocyte count) were significantly greater in the autograft than allograft-without-PRP groups, except for the resorption index at week 24, whereas the differences were not significant between the autograft and allograft-with-PRP groups. The differences between the 2 allograft groups were usually not significant, except for the resorption index. Conclusion. PRP-augmented allografts behaved similarly to autografts for tibial defect reconstruction in rabbits. PRP increased bone union and bone resorption.

Osteomyelitis in the diabetic foot

Osteomyelitis (OM) is a common complication of diabetic foot ulcers and/or diabetic foot infections. This review article discusses the clinical presentation, diagnosis, and treatment of OM in the diabetic foot. Clinical features that point to the possibility of OM include the presence of exposed bone in the depth of a diabetic foot ulcer. Medical imaging studies include plain radiographs, magnetic resonance imaging, and bone scintigraphy. A high index of suspicion is also required to make the diagnosis of OM in the diabetic foot combined with clinical and radiological studies.

Assessment of sensory neuropathy in patients with diabetic foot problems

Our aim of this study was to compare the accuracy of three different modalities for testing sensory neuropathy in diabetic patients with and without diabetic foot problems. The three devices used included the pin-prick testing using the Neurotip® (PPT), the Semmes–Weinstein 5.07/10 g monofilament testing (SWMT), and the rapid-current perception threshold (R-CPT) measurements using the Neurometer® testing. Our study population consisted of 54 patients (108 feet) with diabetic foot problems treated at the National University Hospital in Singapore by our multi-disciplinary diabetic foot care team. Our results showed no difference in sensory neuropathy detected by PPT and 5.07/10 g SWMT in both the pathological and normal foot. In the pathological foot, there was significant increase in sensory neuropathy detected by the Neurometer® device at both the big toe and ankle sites as compared to PPT and 5.07/10 g SWMT. In the normal foot, there was a significant increase in sensory neuropathy detected by the Neurometer® device at the big toe site only as compared to PPT and 5.07/10 g SWMT. Finally, the Neurometer® measurements detected a statistically higher proportion of feet with sensory neuropathy as compared to detection by the PPT or 5.07/10 g SWMT.