Clinical and experimental studies of cigarette smoking in microvascular tissue transfers

Development of a risk-predicting score for hip preservation with bone grafting therapy for osteonecrosis

Identification and differentiation of appropriate indications on hip preserving with bone grafting therapy remains a crucial challenge in the treatment of osteonecrosis of the femoral head (ONFH). A prospective cohort study on bone grafting therapy for ONFH aimed to evaluate hip survival rates, and to establish a risk scoring derived from potential risk factors (multivariable model) for hip preservation. Eight variables were identified to be strongly correlated with a decreased rate of hip survival post-therapy, and a comprehensive risk scoring was developed for predicting hip-preservation outcomes. The C-index stood at 0.72, and the areas under the receiver operating characteristics for the risk score's 5- and 10-year hip failure event predictions were 0.74 and 0.72, respectively. This risk score outperforms conventional methods in forecasting hip preservation. Bone grafting shows sustained benefits in treating ONFH when applied under the right indications. Furthermore, the risk scoring proves valuable as a decision-making tool, facilitating risk stratification for ONFH treatments in future.

Smoking and microvascular free flap perfusion in head and neck reconstruction: radial free forearm flaps and anterolateral thigh flaps

Head and neck reconstruction with microvascular free flaps is frequently performed in smokers. Smoking causes various alterations in the cardiovascular system. The aim of this study was to investigate the effects of smoking on flap perfusion as a critical factor for flap survival. A total of 370 patients reconstructed with a radial free forearm flap (RFFF) or anterolateral thigh flap (ALTF) in the head and neck region between 2011 and 2020 were retrospectively analyzed. Flap perfusion measurements with the O2C tissue oxygen analysis system were compared between nonsmokers, light smokers (< 20 pack-years), and heavy smokers (≥ 20 pack-years). The blood flow was intraoperatively equal in RFFFs (84.5 AU vs. 84.5 AU; p = 0.900) and increased in ALTFs (80.5 AU vs. 56.5 AU; p = 0.001) and postoperatively increased in RFFFs (114.0 AU vs. 86.0 AU; p = 0.035) and similar in ALTFs (70.5 AU vs. 71.0 AU; p = 0.856) in heavy smokers compared to nonsmokers. The flap survival rate was similar in nonsmokers, light smokers, and heavy smokers (97.3%, 98.4%, and 100.0%). Smoking partially increases rather than decreases microvascular free flap perfusion, which may contribute to similar flap survival rates in smokers and nonsmokers.

Progressive Reinvention or Destination Lost? Half a Century of Cardiovascular Tissue Engineering

The concept of tissue engineering evolved long before the phrase was forged, driven by the thromboembolic complications associated with the early total artificial heart programs of the 1960s. Yet more than half a century of dedicated research has not fulfilled the promise of successful broad clinical implementation. A historical account outlines reasons for this scientific impasse. For one, there was a disconnect between distinct eras each characterized by different clinical needs and different advocates. Initiated by the pioneers of cardiac surgery attempting to create neointimas on total artificial hearts, tissue engineering became fashionable when vascular surgeons pursued the endothelialisation of vascular grafts in the late 1970s. A decade later, it were cardiac surgeons again who strived to improve the longevity of tissue heart valves, and lastly, cardiologists entered the fray pursuing myocardial regeneration. Each of these disciplines and eras started with immense enthusiasm but were only remotely aware of the preceding efforts. Over the decades, the growing complexity of cellular and molecular biology as well as polymer sciences have led to surgeons gradually being replaced by scientists as the champions of tissue engineering. Together with a widening chasm between clinical purpose, human pathobiology and laboratory-based solutions, clinical implementation increasingly faded away as the singular endpoint of all strategies. Moreover, a loss of insight into the healing of cardiovascular prostheses in humans resulted in the acceptance of misleading animal models compromising the translation from laboratory to clinical reality. This was most evident in vascular graft healing, where the two main impediments to the in-situ generation of functional tissue in humans remained unheeded–the trans-anastomotic outgrowth stoppage of endothelium and the build-up of an impenetrable surface thrombus. To overcome this dead-lock, research focus needs to shift from a biologically possible tissue regeneration response to one that is feasible at the intended site and in the intended host environment of patients. Equipped with an impressive toolbox of modern biomaterials and deep insight into cues for facilitated healing, reconnecting to the “user needs” of patients would bring one of the most exciting concepts of cardiovascular medicine closer to clinical reality.

Review of Cross-Leg Flaps in Reconstruction of Posttraumatic Lower Extremity Wounds in a Microsurgical Unit

Since the advent of microsurgery, and expanding expertise in the field, extensive traumatic wounds of leg have been managed successfully with free tissue transfer. Various patient-related factors may preclude the use of free flaps even in units with available expertise and infrastructure. It is in such situations that the "cross-leg flap" comes into play. In these cases, instead of attempting complicated anastomotic techniques or anastomosis in the zone of trauma, it is better to perform the simpler and more reliable cross-leg flap. In this study, we try to show the utility of a cross-leg flap based on a retrospective study of 198 patients who underwent cross-leg flap in our institute over a period of 15 years extending from November 2003 to March 2018.

MATERIALS AND METHODS

Case sheets of all patients who underwent cross-leg flap from November 2003 to March 2018 were reviewed. The location of defect in the leg, the indication for cross-leg flap, the pattern of cross-leg flap, and perioperative complications were noted.

RESULTS

A total of 198 patients underwent cross-leg flap for traumatic soft tissue injury of leg during this period. The most common reason for performing cross-leg flap was poor pulsatility of the recipient artery as seen intraoperatively, followed by the economics of the procedure wherein the initial cost of free flap was found significantly higher compared with cross-leg flap. All flaps survived with partial necrosis occurring in 23 patients. All flaps settled well by 2 years' time. Bony union/fracture healing evaluation was not a part of this study.

CONCLUSION

Cross-leg flap is still a useful tool for leg wound coverage even in microsurgical unit in situations precluding free flap coverage.

Tobacco Smoking Associated With Increased Anastomotic Disruption Following Pancreaticoduodenectomy

BACKGROUND

The effect of cigarette smoking on postoperative morbidity following pancreaticoduodenectomy (PD) for cancer is unclear. We hypothesize that smoking is associated with higher morbidity following PD.

METHODS

A retrospective review of patients undergoing PD for cancer from 2010 to 2016 at a single institution was performed. Patients who had never smoked were compared to current or past-smokers with at least 1 pack-year history. Univariate and multivariable analyses were performed.

RESULTS

Two hundred fifty-two patients met inclusion criteria. On univariate analysis, there was a significant difference between smokers and never-smokers in age at diagnosis (65.5 versus 68.6 y, P = 0.013) and fistula rate (28.5% versus 16.2%, P = 0.024). Male sex was significantly associated with fistula rate compared with female sex (15.5% versus 7.1%, P = 0.023). Comparing males and females separately, smoking correlated with higher fistula development only in the male cohort (22.5% versus 5.8%, P = 0.016 in men and 7.3% versus 9.1%, P = 1.00 in women). On multivariable analysis, current and past smoking was independently predictive of developing a fistula: odds ratio of 2.038 (P = 0.030). For current and past-smokers, male sex was an independent risk factor for developing a fistula: odds ratio 2.817 (P = 0.022). There were no other significant differences between groups in rates of postoperative complications.

CONCLUSIONS

Smoking status is independently predictive of postoperative pancreatic fistula following PD for cancer. Among smokers, male sex is an independent risk factor for fistula. Further studies are needed to determine if smoking cessation before surgery decreases this risk, and if so, the optimal duration of cessation.

The Effect of Smoking on Necrosis Rate in Digital Replantation and Revascularization with Prostaglandin E1 Therapy: A Retrospective Study

BACKGROUND

Most microsurgeons believe that smoking and severity of injury adversely affect the outcome of digital replantation surgery. As countermeasures, several pharmacologic agents have been used for the perioperative period. The purpose of this retrospective study was to examine whether the rate of necrosis is appreciably different across smokers versus nonsmokers with prostaglandin E1 therapy.

METHODS

The authors' study subjects included 144 patients (184 digits) who underwent replantation or revascularization between August of 2013 and August of 2015.The primary outcome was the incidence of total necrosis after replantation surgery, and the secondary outcomes were the rate of overall necrosis, proportion of total necrosis to overall necrosis, and total success. Intravenous administration of prostaglandin E1 was performed at the rate of 120 μg/day for 7 days after surgery in all patients. These outcomes of each injury type were compared between smoking and nonsmoking groups.

RESULTS

Among the 184 injured digits, the incidence of total necrosis in smokers (23 percent) was higher than that in nonsmokers (17 percent), although no significant difference was shown (p = 0.36). The adjusted odds ratio was 1.17 (95 percent CI, 0.51 to 2.69). Similarly, there was no significant difference in the secondary outcomes between the two groups.

CONCLUSION

The authors' retrospective study found no significant difference in the formation or extent of necrosis after replantation or revascularization between smoking and nonsmoking groups when all patients were treated with prostaglandin E1.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Unfavourable results in free tissue transfer

With recent advances in the instrumentation and with increased expertise the results of microvascular surgery are getting better. Complications though, cannot be completely avoided. This paper gives a brief introduction to the possible complications at various stages of free tissue transfer. With careful planning and execution and vigilant postoperative care the overall success rate can be improved.

Effects of pentoxyfilline and heparin on reperfusion injury island skin flaps in rats exposed to tobacco

BACKGROUND

Ischemia-reperfusion injury is believed to be a major cause of transferred skin flap failure. Cigarette smoking is known to be associated with endogenous antioxidant depletion, hypercoagulability, and cutaneous vasoconstriction. This investigation was carried out to study possible effects of pentoxyfilline or heparin on rat skin reperfusion injury under tobacco exposure.

MATERIALS AND METHODS

Thirty-six rats were randomized into two major groups: 18 were exposed to cigarette smoke during a 4 wk period prior to surgery; the remaining 18 underwent a sham smoking procedure. Each group was further divided into three equal subgroups: heparin, pentoxyfilline, and saline solution. One identical skin flap was raised in each animal. The vasculature of the flap was clamped for 3 h and reperfused for 5 min. A venous blood sample was obtained from the flap after reperfusion for serum malondialdehyde (MDA) and myeloperoxidase (MPO) analysis. Flap survival was assessed 7 d after the procedure.

RESULTS

The lipid peroxidation levels and flap necrosis were significantly higher in the cigarette-smoking group skin flaps. There was also a decrease of MPO activity in this group compared with the non-smoking group. Heparin-treated rats had significantly lower MDA levels and showed the most viable percent area among smoking rats.

CONCLUSIONS

These data suggest that heparin had a significant beneficial effect both on flap survival and on the lipid peroxidation reduction after smoke exposure in the rat axial-pattern skin flap subjected to ischemia and reperfusion injury. Pharmacologic therapy may represent an alternative way to counteract tobacco effects in flap surgery in emergency situations.

Open calcaneal fractures in diabetic patients with neuropathy: a report of three cases and literature review

Level of Evidence: V, Case Report

Serum cotinine concentration and wound complications in head and neck reconstruction

BACKGROUND

The authors examined whether the preoperative serum concentrations of cotinine accurately predict the risk of complications in patients undergoing flap reconstruction of head and neck cancer defects.

METHODS

Patients with incident stage III or IV squamous cell carcinoma of the head and neck undergoing resection with pedicled or free flap reconstruction were selected from an existing database of 500 patients with squamous cell carcinoma of the head and neck who participated in a prospective epidemiologic study and were reviewed retrospectively. Preoperative serum cotinine concentrations were determined using a competitive microplate immunoassay. Complications were defined as any adverse postoperative wound outcome at either the donor or recipient site.

RESULTS

Eighty-nine patients underwent 101 flap reconstructions. Thirty-seven wound complications occurred in 33 patients. Forty of the 89 patients had a serum cotinine concentration greater than 10 ng/ml; twenty (50 percent) developed postoperative complications, whereas only 13 of 49 patients (27 percent) with a serum cotinine concentration of 10 ng/ml or less developed complications (p = 0.028). The relative risk of wound complications for those with a cotinine concentration greater than 10 ng/ml was approximately double that of patients with a lower cotinine concentration (relative risk, 1.9; 95 percent CI, 1.1 to 3.3). Patients with a cotinine concentration greater than 50 ng/ml had a particularly high risk (relative risk, 2.3; 95 percent CI, 1.1 to 16.7; p = 0.024). The relative risk of wound complications was not significantly associated with self-reported smoking status or history.

CONCLUSION

A serum cotinine concentration greater than 10 ng/ml may predict an increased risk of wound complication in head and neck flap reconstruction and may serve as an objective, easily measured variable with which to identify patients who may benefit from an aggressive smoking cessation program before surgery.

Effects of tobacco smoke on recovery after nerve crush injury in rats

The effects of tobacco smoke on nerve healing after crush injury was studied in a rat model. Thirty-six animals were randomized equally into smoke-exposed or nonsmoke-exposed groups. Two nerve crush injuries were performed on the right posterior tibial nerve of each animal at 4-week intervals to mimic a sustained or chronic nerve injury. Recovery of the two groups was assessed with walking track analysis and nerve histomorphometry. There was no difference in the rate of nerve recovery based on walking track analysis in the smoke-exposed animals compared with nonexposed animals. The study also failed to demonstrate any significant difference between the two groups as assessed by histomorphometric criteria.

If you continue to smoke, we may have a problem: smoking's effects on plastic surgery

Smoking causes various aero-digestive neoplasms, some cardiovascular diseases, respiratory pathologies, and cardiovascular disorders. Surgeons have observed an association between impaired wound healing and smoking. In plastic surgery, cigarette smoking should be forbidden before and after surgery to prevent poor surgical results. In this retrospective study, we presented four major complications related with continuous smoking immediately after surgery. Although we have strongly forbidden smoking for every patient, 4 patients did not follow our advice and continued to smoke. One of them had a breast reconstruction with a pedicled transverse rectus abdominis musculocutaneous flap. Another patient had an abdominoplasty. The third and fourth patients had digital replantation and they were chronic smokers. After their poor surgical outcomes, these heavy smokers received close supervision, but managed to smoke, anyway. Education, psychologic consultation, and sometimes refusing to perform aesthetic or reconstructive surgery are required to minimize postoperative complications.

Clearing the smoke: the scientific rationale for tobacco abstention with plastic surgery

The use of tobacco is a significant contributor to preventable morbidity and mortality in the United States. A significant proportion of cardiovascular diseases, various oral and pulmonary neoplasms, nonmalignant respiratory diseases, and peripheral vascular disorders can be attributed to the use of cigarettes. Surgical outcomes can also be adversely affected as a result of cigarette smoking with intraoperative and postoperative pulmonary, cardiovascular, and cerebrovascular complications as well as increased wound healing complications. These are found across the entire spectrum of surgical specialties. Tissue ischemia and wound-healing impairment secondary to the influence of tobacco is particularly problematic for the plastic surgeon, especially during elective facial aesthetic procedures, cosmetic and reconstructive breast operations, abdominoplasty, free-tissue transfer, and replantation procedures. By educating and providing guidelines to those patients who smoke and by refusing to operate on individuals who fail to abstain, tobacco-associated surgical morbidity in the plastic and reconstructive surgery patient can be eliminated.

Complications of postmastectomy breast reconstructions in smokers, ex-smokers, and nonsmokers

Smoking results in impaired wound healing and poor surgical results. In this retrospective study, we compared outcomes in 155 smokers, 76 ex-smokers, and 517 nonsmokers who received postmastectomy breast reconstructions during a 10-year period. Ex-smokers were defined as those who had quit smoking at least 3 weeks before surgery. Transverse rectus abdominis musculocutaneous (TRAM) flap surgery was performed significantly less often in smokers (24.5 percent) than in ex-smokers (30.3 percent) or nonsmokers (39.1 percent) (p < 0.001). Tissue expansion followed by implant was performed in 112 smokers (72.3 percent), 50 (65.8 percent) ex-smokers, and 304 nonsmokers (58.8 percent) (p = 0.002). The overall complication rate in smokers was 39.4 percent, compared with 25 percent in ex-smokers and 25.9 percent in nonsmokers, which is statistically significant (p = 0.002). Mastectomy flap necrosis developed in 12 smokers (7.7 percent), 2 ex-smokers (2.6 percent), and 8 nonsmokers (1.5 percent) (p < 0.001). Among patients receiving TR4AM flaps, fat necrosis developed in 10 smokers (26.3 percent), 2 ex-smokers (8.7 percent), and 17 nonsmokers (8.4 percent). Abdominal wall necrosis was more common in smokers (7.9 percent) than in ex-smokers (4.3 percent) or nonsmokers (1.0 percent). In this large series, tissue expansion was performed more often in smokers than was autogenous reconstruction. Complications were significantly more frequent in smokers. Mastectomy flap necrosis was significantly more frequent in smokers, regardless of the type of reconstruction. Breast reconstruction should be done with caution in smokers. Ex-smokers had complication rates similar to those of nonsmokers. Smokers undergoing reconstruction should be strongly urged to stop smoking at least 3 weeks before their surgery.

Risk factors for vesicourethral anastomotic stricture after radical prostatectomy

OBJECTIVES

Preoperative comorbidities associated with microvascular disease may contribute to the development of bladder neck contracture (BNC) by alteration of anastomotic healing. We investigated potential risk factors for development of BNC after radical prostatectomy (RP) and reviewed management of this complication.

METHODS

A retrospective review of 467 consecutive patients (mean age 63.2 years) undergoing RP between 1991 and 1999 was performed. In all cases, the bladder neck was tailored to 20 to 22F in a racket handle fashion. After mucosal eversion of the reconstructed bladder neck, a mucosa-to-mucosa vesicourethral anastomosis was created over an 18 to 22F catheter using 4 to 6 anastomotic sutures. The relationship between comorbidities identified preoperatively by patient interview and medical record review (coronary artery disease [CAD], diabetes mellitus [DM], hypertension [HTN], cerebral vascular accident, chronic obstructive pulmonary disease, and smoking history) and the incidence of BNC was determined. Risk factors including prior transurethral prostatectomy (TURP), estimated blood loss (EBL), and operative time (OR time) were also evaluated. Factors were evaluated for their ability to predict BNC using both univariate and multivariate analysis. Treatment results for BNC were also assessed.

RESULTS

A total of 52 (11.1%) patients developed BNC. Current cigarette smoking resulted in a significantly higher (26%) rate of BNC (P <0.001). The BNC rate was also increased in patients with CAD (26%, P <0.001), HTN (19%, P = 0.015), and DM (21%, P = 0.030). Average OR time was longer (271 versus 249 minutes, P = 0.025) and EBL was greater (1639 versus 1092 mL, P <0.001) in patients developing a BNC. In multivariate analysis, current cigarette smoking was the strongest predictor of BNC and independent of other factors (P <0.001). BNC was not related to prior TURP, type of anastomotic suture used, size of catheter, or duration of catheterization. Patients were treated with transurethral dilation (73%) or transurethral incision (27%) and 58% responded to the initial treatment. No patient became incontinent as a result of the treatment for BNC.Conclusions. Several comorbidities associated with microvascular disease are significant risk factors for development of BNC after RP. Current cigarette smoking in particular is a strong predictor. Transurethral dilation and transurethral incision are equally effective as initial treatment of BNC.

Effect of smoking on complications in patients undergoing free TRAM flap breast reconstruction

Free pedicled transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction is often advocated as the procedure of choice for autogenous tissue breast reconstruction in high-risk patients, such as smokers. However, whether use of the free TRAM flap is a desirable option for breast reconstruction in smokers is still unclear. All patients undergoing breast reconstruction with free TRAM flaps at our institution between February of 1989 and May of 1998 were reviewed. Patients were classified as smokers, former smokers (patients who had stopped smoking at least 4 weeks before surgery), and nonsmokers. Flap and donor-site complications in the three groups were compared. Information on demographic characteristics, body mass index, and comorbid medical conditions was used to perform multivariate statistical analysis. A total of 936 breast reconstructions with free TRAM flaps were performed in 718 patients (80.9 percent immediate; 23.3 percent bilateral). There were 478 nonsmokers, 150 former smokers, and 90 smokers. Flap complications occurred in 222 (23.7 percent) of 936 flaps. Smokers had a higher incidence of mastectomy flap necrosis than nonsmokers (18.9 percent versus 9.0 percent; p = 0.005). Smokers who underwent immediate reconstruction had a significantly higher incidence of mastectomy skin flap necrosis than did smokers who underwent delayed reconstruction (21.7 percent versus 0 percent; p = 0.039). Donor-site complications occurred in 106 (14.8 percent) of 718 patients. Donor-site complications were more common in smokers than in former smokers (25.6 percent versus 10.0 percent; p = 0.001) or nonsmokers (25.6 percent versus 14.2 percent; p = 0.007). Compared with nonsmokers, smokers had significantly higher rates of abdominal flap necrosis (4.4 percent versus 0.8 percent; p = 0.025) and hernia (6.7 percent versus 2.1 percent; p = 0.016). No significant difference in complication rates was noted between former smokers and nonsmokers. Among smokers, patients with a smoking history of greater than 10 pack-years had a significantly higher overall complication rate compared with patients with a smoking history of 10 or fewer pack-years (55.8 percent versus 23.8 percent; p = 0.049). In summary, free TRAM flap breast reconstruction in smokers was not associated with a significant increase in the rates of vessel thrombosis, flap loss, or fat necrosis compared with rates in nonsmokers. However, smokers were at significantly higher risk for mastectomy skin flap necrosis, abdominal flap necrosis, and hernia compared with nonsmokers. Patients with a smoking history of greater than 10 pack-years were at especially high risk for perioperative complications, suggesting that this should be considered a relative contraindication for free TRAM flap breast reconstruction. Smoking-related complications were significantly reduced when the reconstruction was delayed or when the patient stopped smoking at least 4 weeks before surgery.

Smoking as a risk factor for injury death: a meta-analysis of cohort studies

BACKGROUND

Injury and tobacco effects represent one-quarter of the global burden of disease. Understanding the causes of injury and the effects of smoking may help reduce those burdens. Some smokers have high risks of injury. We provide an initial meta-analysis of cohort associations between smoking and fatal injury.

METHODS

Three authors independently searched MEDLINE, and bibliographies of the pertinent studies found, for cigarette smoker-specific injury death data which allowed estimation of an appropriate relative risk (RR) and 95% confidence interval (CI). Relative risks and dose response were summarized by fixed effects and Poisson modeling, respectively.

RESULTS

Six studies covering 10 pertinent cohorts were located. Associations between smoking and injury death have been significant after adjustment or, in effect, stratification for age, race, sex, country, and, respectively, alcohol, marriage, education, and body mass; job and time period; job, alcohol, and exercise; etc. Summary dose-response trends were significantly positive (P < 0.00005). Cigarette smoking predicted summary injury death crude RRs of 1.61 (CI 1.44-1.81) vs never smokers and 1.39 (CI 1.25-1.55) vs ex-smokers.

CONCLUSIONS

Smoking has significant, consistent, dose-response, often strong and independent, prospective associations with injury death, internationally.

Cigarette smoking and bone healing: implications in foot and ankle surgery

Despite the known health risks associated with cigarettes, millions of Americans continue to smoke. Much has been reported on the adverse effects of cigarette smoke on wound healing. Recent experimental work and clinical observation have demonstrated the risk of impaired bone healing associated with cigarette smoking. The authors review the biological aspects of bone healing and analyze how the chemical components of cigarette smoke affect the bone healing process. Laboratory and clinical data are also reviewed. Cessation of cigarette smoking before foot and ankle surgery is recommended by the authors.

Smoking and the human vertebral column: a review of the impact of cigarette use on vertebral bone metabolism and spinal fusion

Chronic cigarette consumption has significant adverse effects on the human spinal column. Multiple mechanisms induced by tobacco use lead to less strong, less healthy, mineral-deficient vertebrae with reduced bone blood supply and fewer and less functional bone-forming cells among chronic smokers. Compared to nonsmokers, chronic smokers develop advanced bony degradation, are more likely to suffer from spinal column degenerative disease, and seem more susceptible to traumatic vertebral injury. Spinal fusion procedures in chronic smokers are less often clinically and radiographically successful, compared to similar procedures performed among nonsmokers for definitive biological, physiological, and mechanical reasons.

Fifteen years of experience in treating 2177 episodes of foot and leg lesions with the circulator boot. Results of treatments with the circulator boot

OBJECTIVE

To determine the clinical effectiveness of the end-diastolic pneumatic compression boot and of local antibiotics in treating limb lesions associated with diabetes and peripheral arterial, venous, and neuropathic disease.

RESEARCH DESIGN AND METHODS

Office and hospital data were kept over 15 years on 2177 episodes of leg problems classified by the Wagner method for 1514 legs of 1035 patients largely referred because of failure of standard therapies. The fate of the untreated legs served as a controls when possible.

RESULTS

Healing or improvement of treated legs was seen above that in the literature in all Wagner categories and was significant (P < 0.001) compared to the "control" leg, which deteriorated in 38.7% of patients. Significant risk factors against a successful outcome included smoking, inability to walk, increased home distance from the boot center, loss to treatment, hemodialysis, a Wagner 4-5 classification, inoperable iliac occlusions, vascular procedures before or after referral for boot therapy, and an aggressive vascular surgeon. Neuropathy allowed successful treatment of lesions nondiabetic patients could not tolerate. Relapse was significantly more frequent in arteriosclerosis obliterans (ASO) patients with diabetes than without diabetes and in patients with neuropathy than in those with ASO. Diabetes did not affect the relapse rate in stasis disease. The overall percentage of legs having major amputations was low: 2.5% for diabetic legs at the initial treatment episode, 1.6% at the time of a relapse, and 4.1% after seeking treatment elsewhere. For nondiabetic patients, the respective risks were similar: 2.0%, 1.2%, and 2.9%.