Systematic review of outcomes after surgical management of venous disease incorporating subfascial endoscopic perforator surgery☆

Article Outline

• Abstract
• Methods
  • Literature search and study retrieval
  • Critical appraisal and paper selection
  • Data abstraction
  • Data analysis
• Results
  • Literature search
  • Patient characteristics
  • Ulcer healing
  • Ulcer recurrence
  • Risk factors for nonhealing
  • Risk factors for ulcer recurrence
  • Complications after SEPS
• Discussion
• References
• Copyright

Abstract 

Introduction

In the United States more than 6 million persons have chronic venous insufficiency and more than 500,000 have venous ulcers. Patients in whom conservative therapies fail may improve after surgical treatment of superficial and perforating venous disease, but the degree of this benefit is uncertain.

Purpose

We performed a systematic review of health outcomes in patients with severe chronic venous insufficiency treated with surgical management that incorporated subfascial endoscopic perforator surgery (SEPS), to quantify the overall rates of surgical outcomes.

Methods

Published studies in English reporting venous ulcer healing and recurrence outcomes after SEPS were obtained from a MEDLINE search. Data regarding patient characteristics and surgical outcomes were abstracted from each study, and the outcomes were combined by using a random effects model.

Results

Our search identified 20 studies, 1 randomized trial and 19 case series, involving 1140 treated limbs. CEAP classification was secondary cause (E_S) in 36%, deep venous involvement (A_D)in 56%, and obstructive (P_O) in 12%. Overall, after surgical treatment including SEPS, with or without concomitant superficial venous ablation, ulcers in 88% of limbs healed. Ulcers recurred in 13%, at mean time of 21 months. Risk factors for nonhealing and recurrence included postoperative incompetent perforator veins, pathophysiologic obstruction, secondary cause, and ulcer diameter greater than 2 cm. Complications and their overall rates after surgical treatment including SEPS were wound infection (6%), hematoma (9%), neuralgia (7%), and deep venous thrombosis (1%).

Conclusion

Our results suggest that surgical management of venous ulcer including SEPS, with or without saphenous ablation, leads to an 88% chance of ulcer healing and a 13% chance of ulcer recurrence over the short term. Randomized controlled trials are needed to discern the contributions of compression therapy, superficial venous surgery, and SEPS in the treatment of venous ulcer disease.

More than 6 million persons in the United States have chronic venous insufficiency,1 leading to treatment costs of up to $2.5 billion2 and 2 million lost workdays annually.3 Venous ulcer accounts for much of this morbidity and treatment cost, because the natural history of this disorder is slow healing and high recurrence rate.4 Despite vigorous efforts at conservative therapies such as compression dressings and elevation, many patients fail to improve. Surgical approaches such as the Linton procedure and subsequent modifications of this procedure sought to eliminate perforator vein incompetence and therefore favorably affect venous hemodynamics and clinical outcome.5 While some studies have reported good results, morbidity related to wound complications has led many to abandon this procedure.6

Subfascial endoscopic perforator surgery (SEPS) enables surgeons to address perforator vein incompetence less invasively, with small upper calf incisions remote from severely diseased skin in the distal leg. SEPS is performed in many centers as a component of a comprehensive treatment program for venous insufficiency,7 but few studies have compared SEPS with the Linton procedure. In the only randomized trial, Pierik et al8 found similar ulcer healing and recurrence rates and lower surgical complication rates with SEPS, but the study was too small to enable definitive conclusions about the efficacy of SEPS. The rest of the studies incorporating SEPS have had an observational study design, often without comparison treatment groups, so the usefulness of SEPS in patients with venous disease remains uncertain.

When there is controversy regarding the efficacy of an intervention a systematic review of the literature to summarize the available data may be helpful. In a systematic review, investigators follow a specified protocol to conduct a comprehensive literature search, to apply well-defined inclusion and exclusion criteria to selected studies that address the research question, and to critically appraise the methodologic quality and applicability of the studies. When sufficient data exist, meta-analysis can be performed to combine the data, with appropriate statistical methods to increase the precision of the overall estimate of the treatment effect.9 The goal of this systematic review is to summarize the best available evidence on the outcomes of SEPS for treatment of venous disease and to identify risk factors for adverse outcomes associated with this procedure.

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Methods 

The steps in performing a systematic review include formulating a question, literature search and study retrieval, critical appraisal and paper selection, data abstraction, and statistical analysis and interpretation. We sought to answer the question, What are the rates of various surgical outcomes after SEPS for venous ulcer as reported in the literature?

Literature search and study retrieval 

We performed a MEDLINE search in Ovid (Ovid Technologies, New York, NY), using the MeSH terms “venous insufficiency/surgery, varicose ulcer/surgery, and leg ulcer/surgery” or the key word “perforator,” and combined these with the exploded MeSH term “endoscopy,” and limited our search to Human and English language studies. In addition we searched references of review articles and of retrieved studies, and consulted local experts regarding recently published papers. The initial search from 1966 to November 2002 provided 72 citations, and after two new trials were reported in December 2002, the same search strategy in January 2003 retrieved six additional citations.

Critical appraisal and paper selection 

To be included, a study must have reported the number of patients with active ulceration at the time of SEPS and with ulcer healing during follow-up. Because there was only one randomized trial, we included nonrandomized studies in our systematic review. We excluded studies with fewer than 10 patients with active ulcers. To minimize the risk for double counting in the analysis of healing and recurrence, we included only one paper when there were multiple reports from the same institution during the same period. When reported healing and recurrence outcomes could not be clearly defined we contacted study authors.

Data abstraction 

Two independent reviewers abstracted the following data from the studies, using specified data abstraction sheets: patient demographics; CEAP classification; outcomes, including healing, recurrence, and complications; and factors associated with adverse outcomes. We defined overall healing as the number of patients with class 6 disease that healed by the time of the latest reported follow-up, but we also collected data on healing within 30 days, within 60 days, and beyond 60 days in the subset of studies reporting these data. Ulcer recurrence was recorded for patients with class 5 and class 6 disease that healed after SEPS. Complications included in the analysis were infection, saphenous or sural neuralgia, hematoma, and deep venous thrombosis (DVT). We also collected data on risk factors associated with nonhealing and ulcer recurrence.

Data analysis 

We used a random effects model to combine two kinds of data: proportions, such as percent of limbs with ulcer healing; and odds ratios, which measure the strength of the association between a risk factor, such as secondary cause, and an outcome, such as failure to heal. The random effects model incorporates both within-study variance and between-studies variance in assigning a weight to individual studies in a meta-analysis. Compared with the fixed effects model, in which only within-study variance is used for weight, the random effects model is generally more conservative, usually resulting in a wider confidence interval.

For combining proportions we used an extension of the DerSimonian and Laird random effects model.10, 11 We calculated the logit of the proportion, then combined the logits with a random effects model, and finally re-transformed the result to arrive at a summary estimate.12 The logit transform of the proportion was undertaken to ensure that the data would comply with the normality assumption for meta-analysis and that the resultant confidence intervals would not be nonsensical (ie, confidence intervals with values less than 0% or greater than 100%). Meta-analyses were performed with Meta-analyst 0.99 computer software (created by J.L.) to calculate point estimates and 95% confidence intervals (CI).

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Results 

Literature search 

The literature search in January 2003 yielded 112 citations. This number was reduced to 78 after limiting to Human and English language studies. After excluding duplicate reports, 18 articles had data on healing outcomes after SEPS.6, 7, 8, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 Two studies found in references of included studies were added,28, 29 for a total of 20 included studies. Of these, 19 were case series and 1 was a randomized trial that compared open perforator ligation with SEPS.8

Patient characteristics 

Study and patient characteristics are listed in Table I. The studies included 1031 patients, with 1140 treated limbs. All patients had symptomatic venous insufficiency of clinical class I to III by previous classifications, and class 2 to 6 by CEAP classification: 526 limbs (46%) had active ulcer at the time of SEPS, and 70% of limbs with available data had CEAP class 5 or 6 disease. Average age was 57 years (range, 44-67 years) in individual studies, and 51% of patients were female (range, 11%-75%). In the 4 studies that reported mean ulcer size, average diameter was 6 cm (range, 2.8-9 cm).8, 15, 27, 29 The average duration of ulcer was 29 months (range, 8-144 months) in the seven studies in which it was reported.6, 8, 15, 17, 24, 27, 29

Table I. Study characteristics

NA, Data not available.

Other CEAP characteristics indicating more severe venous disease included secondary cause (E_s) in 36%, deep venous insufficiency (A_D) in 56%, and pathophysiologic findings including obstruction (P_O) in 12%. Because perforator vessel incompetence is de facto reflux, all limbs were also designated as such (P_R). Overall, 67% of patients underwent concomitant procedures for superficial venous insufficiency, including saphenous vein stripping and ligation (Table I).

Ulcer healing 

The ulcer healing rate of the SEPS arms of the 20 studies ranged from 56% to 100%. Combining all 20 studies, we found that ulcers healed in 88% (CI, 83%-92%) of limbs. The mean follow-up at which 17 of these studies reported percentage of healing was 10 months. In the subset of 9 studies that reported healing by time of follow-up,7, 15, 17, 19, 20, 24, 26, 30, 31 40% (CI, 27%-53%; range, 31%-91%) of ulcers healed within 30 days, 64% (CI, 53%-74%; range, 48%-100%) healed within 60 days, and 86% (CI, 77%-92%; range, 56%-100%) healed after 60 days (Fig 1). From this subset the median time to healing was 30 to 60 days. For ulcers that did not heal in the first 30 days, 40% healed by 60 days; and for ulcers that had not healed by 60 days, 61% healed by the end of study follow-up.

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• Fig 1. 

  Cumulative ulcer healing. Box-and-whiskers plot depicts ulcer healing after subfascial endoscopic perforator surgery in patients with class 6 disease in subset of studies with data for time to healing (nine studies, 264 limbs). y-axis shows percentage of limbs that healed during follow-up; x-axis depicts three healing end points, number of limbs, and number of studies that contributed to each end point. Horizontal lines, End points; boxes, 95% confidence intervals; error bars, range for individual studies that contributed to each estimate; Longest follow-up, healing by end of follow-up.

Ulcer recurrence 

Probability of ulcer recurrence is shown in Fig 2. For patients with class 5 disease at surgery, ulcers developed in 16% (CI, 10%-24%; range, 0%-33%) during follow-up. For patients with class 6 disease at surgery in whom ulcers subsequently healed, 16% (CI, 11%-21%; range 0%-28%) had ulcer recurrence during follow-up. When patients with class 5 and class 6 disease were combined, that is, all patients at risk for recurrence, 13% (CI, 9%-18%; range 0%-28%) had ulcer recurrence. For the 8 studies that reported time of follow-up when ulcers recurred (21 of 77 recurrences),7, 8, 14, 18, 19, 22, 28, 29 mean time to recurrence was 21 months. Total mean follow-up among 16 studies reporting these data was 29 months.6, 7, 8, 13, 14, 15, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28

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• Fig 2. 

  Ulcer recurrence. Box-and-whiskers plot depicts ulcer recurrence after subfascial endoscopic perforator surgery (SEPS). y-axis shows percentage of limbs with ulcer recurrence during follow-up; x-axis depicts three categories of limbs, number of limbs, and number of studies that contributed to each end point. Horizontal lines, Point estimates; boxes, 95% confidence intervals; error bars, ranges for individual studies that contributed to each estimate; class 5, recurrence in limbs with class 5 disease at SEPS; class 6, recurrence in limbs with class 6 disease at SEPS in which ulcers subsequently healed; combined, recurrence in limbs with class 5 and class 6 disease. Number of limbs and studies in class 5 and class 6 do not total those in the combined group, because not all studies reported data separately for limbs with class 5 and class 6 disease.

Risk factors for nonhealing 

To explore risk factors for nonhealing, we first identified factors examined in individual studies. For each study with available data we then estimated the odds ratio to quantify the association of individual factors with nonhealing. Finally, we pooled odds ratios to obtain a summary estimate of the association of each risk factor with nonhealing (Table II).

Table II. Factors associated with nonhealing

SEPS, Subfascial endoscopic perforator surgery; CI, confidence interval.

The presence of postoperative incompetent perforator vessels detected with Doppler ultrasound scanning was reported to be a significant risk factor for nonhealing in two studies8, 32 of the four studies that reporting healing stratified with this risk factor.8, 22, 23, 32 Combining odds ratios for these four studies resulted in significantly increased odds for nonhealing in patients with postoperative incompetent perforator vessels. Ulcer diameter greater than 2 cm was reported to be significantly associated with nonhealing in three studies7, 18, 23 of the four studies that reported this outcome.7, 18, 23, 29 Data for odds ratios were available only for the three positive studies, and combining these studies resulted in a statistically significant increase in the odds of nonhealing for ulcers greater than 2 cm in diameter. Six studies reported healing stratified by primary versus secondary cause,6, 7, 18, 19, 22, 23 and in two of these, secondary cause was reported to be a significant risk factor for nonhealing.7, 19 We calculated odds ratios in five studies (two positive,7, 19 three negative22, 23, 30), and combining these showed a significant increase in odds of nonhealing in patients with secondary cause. Note that confidence intervals were wide, reflecting variation among studies (Table II).

Results for patients with and without obstructive pathophysiology were reported in four trials,7, 18, 22, 23 one of which found that obstruction was a significant risk factor for nonhealing,23 and another found significantly longer time to healing in patients with obstruction.18 Combining the three trials with available data (one positive,23 two negative7, 22) did not find obstruction to be a significant risk factor for nonhealing. Deep venous involvement was not a significant risk factor for nonhealing in any of the five studies that reported this outcome7, 22, 23, 24, 27 or in four studies combined that had available data.7, 22, 24, 27 Four studies reported healing results on the basis of concomitant saphenous vein ablation.7, 20, 23, 24 Combining the three studies with available data7, 20, 24 resulted in a lower risk for nonhealing in patients who underwent concomitant saphenous vein ablation, but this did not reach statistical significance (Table II).

Two studies reported that the presence of a recurrent ulcer at surgery, as opposed to a new ulcer, was not a significant risk factor for nonhealing.18, 23 Although two studies reported that time to healing was longer in patients with longer duration of ulcer before surgery,17, 33 six studies found no association between duration of ulcer before surgery and failure to heal.17, 18, 22, 23, 29, 33 The two studies with available data for odds ratios were not pooled, because cutoff for duration in one study was 3 months31 and in the other it was 35 years.22

Risk factors for ulcer recurrence 

Factors associated with recurrence are shown in Table III. Obstruction was a significant risk factor for recurrence in two18, 23 of three studies.18, 22, 23 Combining odds ratios for these three studies resulted in a significant increase in odds of recurrence in patients with obstruction. Secondary etiology was reported to be a significant risk factor for recurrence in three18, 20, 23 of five studies that reported this outcome.7, 18, 20, 22, 23 Combining odds ratios for the four studies with available data (two positive,18, 20 two negative7, 22) resulted in a significant increase in odds of recurrence in patients with secondary etiology. Again, CI were wide, reflecting variation among studies (Table III).

Table III. Factors associated with ulcer recurrence

Postoperative incompetent perforator veins were a significant risk factor for recurrence in two18, 34 of the four studies that reported this outcome,18, 22, 23, 34 and combining data from these four studies resulted in a significant increase in the odds of recurrence in patients with postoperative incompetent perforator vessels. Deep venous involvement was not a significant risk factor for recurrence in the four studies that reported this outcome7, 22, 23, 28 or when data were combined for the three studies with available data7, 22, 28 (Table III).

Complications after SEPS 

Early surgical complications, as defined in each study, are shown in Fig 3. Wound infection was reported in 6% of patients (CI, 4%-8%; range, 0%-16%). Hematoma was reported in 9% of patients (CI, 6%-13%; range, 0%-23%), but definitions of this end point varied among studies. Some included mild hematomas; others reported only those requiring repeat intervention. Neuralgia was reported in 7% of patients (CI, 6%-9%; range, 0%-17%). Most studies did not specify whether the neuralgia was persistent or transient, but one study reported a much lower incidence of persistent neuralgia.27 DVT within 30 days of operation was reported in 1% of patients (CI, 0.7%-3%; range, 0%-2%). We included in this analysis the seven studies that explicitly reported no DVT, but we excluded several studies that reported no major complications without explicitly referring to DVT. No perioperative deaths or pulmonary emboli were reported in these studies.

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• Fig 3. 

  Early complications. Box-and-whiskers plot depicts early complications after subfascial endoscopic perforator surgery. y-axis shows percentage of patients with complications; x-axis depicts complications, number of limbs, and number of studies that contributed to each end point. Point estimates are shown next to boxes, which represent 95% confidence intervals; error bars, ranges for individual studies that contributed to each estimate. DVT, deep venous thrombosis.

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Discussion 

For patients with severe chronic venous insufficiency and active venous ulcer, an intervention that improves healing and recurrence has the potential to improve quality of life and reverse disability associated with this condition.3 In our systematic review of mostly observational studies with 1140 treated limbs in a patient population with severe venous disease, surgical treatment that included SEPS, with or without saphenous vein ablation, and conservative management resulted in healing of ulcers in 88% of limbs. An estimated 40% healed by 30 days, and 64% by 60 days. Ulcer recurrence in 611 limbs at risk was 13%, with mean time to recurrence of 21 months. Complications from these surgical procedures included wound infection in 6%, hematoma in 9%, neuralgia in 7%, and DVT in 1%, but serious complications such as thromboembolism and perioperative mortality were surprisingly low.

The healing and recurrence outcomes compare favorably with trials of conservative therapies,35 even though the patient population in these surgical studies generally had severe venous disease and previous conservative therapies had failed. Except for the 1991 study by Maybery et al,36 most other reports of compression therapy have found lower healing rates.35 In a randomized controlled trial of several medical treatments combined with compression therapy, ulcers in 14% to 31% of patients healed by 4 weeks,37 less than the 40% healing at 30 days in the present systematic review. Ulcer recurrence in 611 limbs at risk was 13%, with mean time to recurrence of 21 months, which also compares favorably with conservative therapy.38

Identifying risk factors that predict poor outcomes, such as nonhealing and recurrence after surgical approaches that incorporate SEPS, would be useful clinically. Studies reported different results on the association of risk factors with adverse outcomes (Table II, Table III), and understanding this discrepancy is important. We found that postoperative incompetent perforator veins, obstructive pathophysiology, secondary etiology, and larger ulcer increased the odds of these adverse outcomes by about 4-four to 14-fold. However, there is considerable uncertainty in the estimate, as evidenced by the wide confidence intervals.

Reported outcomes such as healing and recurrence varied broadly, and this may reflect differences in patient-specific or technique-specific factors. The patient populations differed in the proportion of patients with several key risk factors for adverse outcomes. Some studies that had high healing rates may have had patients with favorable risk profiles. The use of concomitant superficial venous insufficiency procedures also varied among studies (Table I), which is important because saphenous vein ligation by itself may improve outcome in venous disease. We were unable to evaluate the direct effect of saphenous vein ablation, because individual studies generally did not report outcomes stratified by the use of concomitant procedures. For example, patients who have already undergone saphenous vein ablation before SEPS may represent a subgroup at higher risk that may have poorer outcomes.

Other surgical characteristics that may contribute to the variability in outcomes include extent of perforator vesssel ligation, individual surgeon experience, and use of skin grafting. We found that postoperative incompetent perforator vessels are associated with nonhealing and recurrence, but it is not known whether these veins were missed at operation or arose de novo.34 Variation in surgical technique and individual surgeon experience may account, at least in part, for variation in rates of postoperative incompetent perforator vessels. Also, use of skin grafts varied among studies (some routinely applied skin grafts in all patients with large ulcers25), and this could have contributed to variability in outcomes. In the one study that reported healing according to presence or absence of skin grafting the healing rate was higher in patients with skin grafts, but the difference was not statistically significant.17

Lack of adherence with compression stockings postoperatively was not significantly associated with ulcer recurrence in the North American Subfascial Endoscopic Perforator Surgery Registry (NASEPS),23 but this is the only study reporting an outcome stratified by level of patient adherence. Another study reported good adherence in patients who responded to therapy.29 Other observational studies have reported up to 100% recurrence rate in patients who are noncompliant with compression therapy,36 so adherence is probably important, and variability in compliance among studies could also account for some of the variability in outcomes.

There are several limitations of this systematic review. First, most meta-analyses of interventions involve combining randomized controlled trials to estimate the relative efficacy of one intervention over another. For this systematic review, data from all but one of the trials came from cohorts that lacked a comparison group, so the efficacy of SEPS cannot be directly compared with another treatment. Studies differed in clinical characteristics of their populations, in their definitions of outcomes (hematoma or major hematoma only), and in reporting of outcomes (specific presence or absence of DVT). Also, because some patients underwent bilateral surgery, some outcomes may have been affected by clustering of risk factors for both limbs. The NASEPS Registry contributed the largest number of patients, but its inclusion in this analysis introduces some difficulties. While we excluded studies identified by the authors as part of the Registry, some included studies may have been part of it, and therefore some patients may have been counted twice.

As with any systematic review, the results are limited by the available data. Publication bias, in which studies with positive results are more likely to be published than those with negative results, may be more prevalent for case series than for randomized controlled trials. For overall healing, all 20 studies had usable data, and for recurrence there were 18 studies. The analysis of risk factors associated with adverse outcomes was limited to three to seven studies that reported outcomes stratified according to patient characteristics. In addition, analyses were performed on the subset of three to five studies with data available for calculating odds ratio. It is possible that the exclusion of a study or studies that reported an association but did not have usable data for meta-analysis could bias the result, so results of the analysis of risk factors should be interpreted with caution. More detailed individual patient data would enable construction of statistical models adjusting for factors that influence patient outcomes, and construction of meta-analysis survival curves.39

Inclusion of some of the studies in this systematic review may have resulted in less favorable results than might be found today. For example, some of the studies presented preliminary data and outcomes that might have reflected a learning curve for the procedure. In a 1996 study ulcers did not completely heal in four of nine patients,40 but in the 1999 mid-term report of the NASEPS Registry the cumulative ulcer healing rate was about 88% at 1 year.23

In this study we endeavored to clarify the outcomes of surgical treatment including SEPS and to report on factors that affect outcomes. The statistical methods used enabled us to make use of the published data. However, the quality of any analysis depends on the quality of the data. In the future authors should be encouraged to adhere to the reporting standards in venous disease,41 to both support their conclusions and enable future meta-analyses. This systematic review demonstrated excellent results in terms of ulcer healing and prevention of ulcer recurrence when SEPS was used as part of a treatment regimen for severe chronic venous insufficiency. However, prospective randomized trials are required to define the relative contributions of compression therapy, superficial venous surgery, and SEPS in the management of severe venous disease.

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