Dr. Anthony J. Dixon. MB,BS. FACRRM. Dip.RACOG.
Dermasurgeon & Senior Lecturer, School of Medicine, University of Queensland, Australia
Assoc. Prof. John B. Dixon, MB,BS. PhD. Dip.RACOG. FRACGP.
Assoc. Prof. Centre for Obesity Research, Monash University, Melbourne, Australia
Method: This retrospective study compares 140 defects closed with a reducing opposed multilobed (ROM)) flap6 with 85 defects closed with traditional techniques.
A total of 225 defects between 11 and 44 mm in diameter were excised over 3 years from July 1st 2002.
There were 140 defects closed by ROM flap and 85 non ROM closures including 29 “O-to-Z” flaps and 12 bilateral transposition flaps. A total of 111 squamous cell carcinomas, 64 basal cell carcinomas, and 11 melanoma were excised.
ROM flap closures developed 20 complications (14.3%) 13 infections, 5 partial wound dehiscence, and 2 partial end flap necrosis.
Non-ROM closures developed 27 complications (31.8%):13 infections, 6 partial end flap necrosis, 4 partial dehiscence, 2 wound depression, 1 hemorrhage, and 1 persisting pain. Three ROM and 7 non-ROM cases suffered two complications.
The total complication rate was significantly lower with ROM flaps (P=.003), including lower end flap necrosis incidence. (P=.027)
The ROM flap results in fewer complications than traditional techniques when closing defects 11 to 45 mm in size on the leg and foot. In particular, end flap necrosis incidence is lower with ROM flap closure.
Managing skin cancers below the knee poses special problems for the surgeon. Wounds heal poorly compared with other skin sites on the body. Skin is often tight, especially on the shin, limiting its mobilization to close an adjacent defect. Circulation is often reduced or poor. Infection rates can be higher than elsewhere on the body.
Small defects (less than 11 mm in diameter) are usually able to be closed directly. Larger wounds become increasingly difficult to close directly due to skin tension.
Skin grafts can be used to close large leg wounds. Grafts do not suffer the tension issues faced with direct closure. However, grafts have their own difficulties, including failure to take and poor aesthetic outcomes. Wound depression is so common in skin graft closures that it is almost an expectation. Further, skin grafts on the leg require considerable periods of elevation and immobilization and the associated health risks such as deep venous thrombosis (DVT). Nevertheless, Skin grafts remain the most common realistic closure technique for large leg defects, (> 45 mm diameter).186
But what of medium sized defects, 11 – 45 mm in diameter? These defects are often too large to close directly, yet it would be disappointing to subject the patient to a graft for a defect of this size.
Many random pattern skin flaps such as rotation, advancement, transposition and island pedicle flaps have been used for these medium sized defects186, 187, 194. Bilobed type random pattern skin flaps, though initially described for nose defects150, 190, have found usage elsewhere including below the knee. End flap necrosis rates can be high, however, with delayed healing and wound breakdown common. Patients may spend lengthy periods before returning to normal ambulation and activity.
Other techniques including cross leg193 and meshed192 flap techniques have been described, but have significant functional and / or aesthetic disadvantages for the patient and may be more appropriate for larger defects.
Axial, fascio-cutaneous and related flaps remain an option for large defects but have the disadvantage that subcutaneous sheath and tissues are incised and mobilized86, 189, 191, 195, 196. These flaps are also predominantly for usage in other circumstances and for larger defects.
Defects can be left to heal by second intention. This often results in lengthy periods of leg elevation as well as delays in returning to normal ambulation and activity. Further, patients with wounds healing by second intention can suffer non healing and chronic ulceration problems.
The reducing opposed multilobed (ROM) flap6 was developed from first principles to attempt to address the traditional problems associated with random pattern skin flaps and second intention healing below the knee. (Figure 1) Using the ROM technique, all skin flaps have a low Length –to-Base ratio of 0.5. (Figure 2) Further, there are no “up-hill” flaps involved in this closure where the base of the flap is distal to the end of the flap. For these reasons the end flap necrosis rate and wound breakdown risk should be reduced when below knee defects are closed using this technique.
Skin “wastage” is also an issue in below knee defect closures. An elliptical closure can result in up to twice as much skin being excised as would be required for excising the lesion with an appropriate margin alone. If several skin lesions are excised, then the increasing loss of otherwise normal skin compounds the patient’s ongoing skin loss problems.
The ROM flap technique involves no skin wastage while enabling the patient to mobilize the same day as the surgery. While the theoretical benefits of the ROM flap are encouraging, evidence is needed to identify whether this translates into benefits for the patient.
The aim of the retrospective analysis was to ascertain whether theoretical benefits from the usage of the ROM flap below the knee were borne out by improved outcomes and fewer complications.
We retrospectively analyzed all patients treated at a dedicated skin cancer surgery unit over three years between July 1st 2002 and June 30th 2005.
We excluded all tumours managed by non surgical means. Only lesions excised and defects closed with suture were included. We also excluded any defect smaller than 11mm in size or larger than 45 mm in size. All skin sites below the knee were included. This includes the foot.
There were no exclusions based on medical conditions, including diabetes, peripheral vascular disease, peripheral neuropathy, Alzheimer’s disease and peripheral edema. Further, a tight or inflamed skin character did not lead to exclusion.
The age and sex of each patient was noted as well as whether they were diabetic, a smoker or were on anticoagulant therapy. In keeping with recommended practice197, anticoagulants would not be ceased other than in the event that INR levels were over the therapeutic range.
The retrospective study involved consecutive sequential series of patients. Non ROM techniques were used from July 2002 until October 2003. With the introduction of the ROM technique in October 2003, all medium sized defects were then closed with ROM flaps. The change of practice in October 2003 followed frustration with complication rates from existing techniques and the identification of significant theoretical advantages with the ROM technique. Other than the change in closure technique, no other change in management was implemented. Post operative antibiotics were only given if infection was apparent. Preparation and dressing protocols were consistent throughout. No patient received preoperative prophylactic antibiotics.
The ROM technique has been described previously by us6. Briefly it involves a series of semicircles extending strictly in a cephalic and caudal direction from the primary defect, (Figure 3). Semi circles closest to the defect are 65% of the diameter of the primary defect. Each subsequent semi circle is 65% of the diameter of the previous semicircle. The process of reducing semi circles continues until a 5 to 8 mm semicircle is planned.
The technique involves a series of transpositions. The outer smallest semi circles are transposed into the adjoining semicircular defect. This process continues until the largest semi circular flaps are joined together to close the central defect. The resulting wound appears as a “zig-zag” type line running cephalo-caudal down the leg. (Figure 4)
All surgery was undertaken by one surgeon. All wounds were closed with polyamide interrupted cutaneous sutures. No wound closures involved deep, subcutaneous or intradermal suturing. While such deep sutures can be useful in approximating skin edges, they are not the usual practice of this surgeon when closing defects below the knee. Surgery was undertaken with sterile gloves, equipment and drapes. The surgeon wore mask and gown. All wounds were occlusively dressed post suturing. A follow up of at least 4 weeks was undertaken on every case by consultation with the surgeon. They were also followed up by phone by nursing staff. Alternate sutures were removed two weeks after surgery with the remaining sutures removed five to seven days later.
All ROM patients were allowed to walk the same day as surgery but were asked to minimize walking for the first 24 hours following surgery. They were then progressively allowed to increase ambulation. When seated over the first three days following surgery, patients were encouraged to elevate legs where possible.
All non ROM closure patients were asked to avoid any walking for 2 days and were then advised to slowly return to normal ambulation. Skin graft patients were further advised to elevate their leg for at least 7 days where possible.
In the event that a wound dehisced or broke down, healing by second intent was effected, with minimal debridement undertaken when appropriate. All complications were assessed and recorded. Analysis was on an intention to treat basis.
All complications noted at any stage were recorded. Specifically, infection, haemorrhage, pain, dehiscence, end flap necrosis, oedema, delayed wound healing, chronic ulceration, elevation, depression, contour distortion, etc were all specifically assessed in the convalescence period.
Infection was assessed clinically based on finding three out of the following four clinical measures ; induration, erythema, pain and discharge. Any patient experiencing wound pain three months following surgery was deemed to have persistent pain.
We calculated that we needed at least 74 cases and controls in order to have a power of 0.8 to detect a reduction in the complication rate by 50% from 40% to 20% with a p value of < .05
Descriptive statistics regarding subjects were presented as mean values. Differences in proportions of complications between groups were assessed using Chi square test.
A total of 417 below knee post excision closures were effected on below knee wounds in the skin cancer surgery centre from July 1st 2002 until June 30th 2005. No tumor required excision of tissue beyond fat and surrounding subcuticular soft tissue structures.
A total of 189 defects were below 11 mm in size and were closed directly. Three defects were more than 45 mm in size and were closed with partial thickness skin grafts.
A total of 225 defects were medium in size (between 11 and 45 mm in diameter) and were hence included in this analysis. The diagnoses managed to produce these 225 defects are detailed in Table 1.
A total of 111 were squamous cell carcinoma and 64 were basal cell carcinomata.
A total of 140 medium sized defects were repaired with ROM flaps. Of these, 135 defects were fully closed while the remaining five defects were reduced in size by at least 80% by incompletely closed ROM flaps. Two of these residual defects had a graft applied. Three residual defects were left to heal by second intent. The largest size of the five residual defects was 13 x 12 mm in size. These five cases were included with the other ROM flaps in analysis on an intention to treat basis.
Eighty-five medium sized defects were closed with procedures other than the ROM flap. Twenty-two of these defects were closed directly. Sixty-one defects were closed with random pattern skin flaps that were not ROM flaps. Twenty-nine of these flaps were “O to Z” type closures. Six defects were closed with simple transposition flap repairs. Twelve defects were closed with bilateral transposition flap repair. An additional six defects were closed with bilobed type transposition flap repairs. The remaining 8 random flap closures were; 1 “A to T” repair, 2 rhombic transposition repairs, 2 simple rotation flaps, 1 “V to Y” type island advancement flap and 1 triple transposition flap repair.
There were no significant differences in the characteristics of the two groups of patients. ROM flap patients had a mean age of 58.0 years compared with non ROM patients whose age was 59.8 years on average. There were 104 defects on men and 121 defects on women included in the study. Nine per cent of patients were on Warfarin therapy while 24% were on Aspirin therapy. Fourteen per cent of patients were diabetic and 15% of patients were smokers.
The range of defects closed with ROM flaps varied from 11 to 44 mm in diameter. Defects closed by other techniques varied from 11 to 31 mm in diameter. There were no defects between 31 and 45 mm in this study until the ROM technique was being used.
This is a consecutive series. All non ROM closures were undertaken between July 1st 2002 and October 2003. All ROM flap closures were undertaken between October 2003 and June 30th 2005.
In both groups wounds that suffered infection, wound dehiscence or end flap necrosis were allowed to heal by second intent. No wound underwent flap / scar revision.
Two defects were electively closed with split skin grafts. Both of these developed wound infections. As there were few split skin grafts and as graft outcomes are known to be different to closures where skin edges retain their blood supply at closure, the skin grafts were excluded from further analysis.
Complications experienced (Table 2)
A total of 140 ROM flap closures experienced 20 complications in 17 closures. Three ROM closures suffered both infection and partial wound dehiscence.
Eighty-three non ROM closures (closed either directly or by non ROM random pattern flaps) experienced 24 complications in 18 closures. Six non ROM closures suffered two complications.
Partial end flap necrosis was low in the ROM group with only two cases experienced (1.4%). In contrast, six non ROM closures suffered partial end flap necrosis, (7.2%). This difference was significant. (p = 0.024)
Post operative infection was experienced in 13 ROM cases, (9.3%) versus 11 non ROM closures, (13.3%) p=0.36
All but one of the wound infections resolved with oral Dicloxacillin 500mg four times daily. One ROM flap wound infection did not respond to Dicloxacillin but responded subsequently to Ciprofloxacin 750 mg twice daily for 10 days.
Partial wound dehiscence was experienced in five ROM cases (3.6%) versus four non ROM cases (4.8%) This difference was not significant (p=.65). No dehiscence extended the full length of the wound.
While post operative infection and dehiscence rates were not significantly different, the trend favored ROM flap repairs. This contributed to an overall complication rate of 20 (14.3%) in ROM cases and 24 (28.9%) in non ROM cases. This difference is highly significant. (p=.008)
Seventeen ROM wounds suffered one or more complications, (12.1%). In contrast, 18 non ROM wounds suffered one or more complications (21.7%). (p=.06)
We effected a sub-analysis of “O – Z” repairs given they were the most common of the non ROM techniques used in this series. The 29 cases closed with “O – Z” type flap repairs suffered a total of 7 complications (24.1%). These were two infections, three cases of end flap necrosis, one persistent pain and one wound dehiscence. Although “O – Z” closures suffered a lesser percentage of complications than the other non ROM flaps, the difference was not significant, (p=0.25).
There was no case of intra-operative bleed beyond 100ml and no case of postoperative bleed in those patients continuing to take anticoagulants. No patient had a pre-operative INR in excess of therapeutic range. As such, none of the 72 patient taking Warfarin and / or aspirin discontinued their medication. There was no case of lymphoedema experienced.
All ROM patients tolerated the procedure well, with no patient expressing concern or disapproval with their surgery. In contrast one patient following skin graft, one patient following bilateral transposition repair and one patient following “O – Z” repair complained of the slow healing and length of time to return to full mobilization. All ROM patients had excellent final cosmetic outcomes, including the five cases that did not fully close with the ROM technique alone. There was no ROM closure that resulted in an unsightly scar, wound depression or elevation.
Patients with defects closed with ROM flaps suffered significantly fewer complications while walking early post surgery, - the same day.
The theoretical modeling of the ROM flap suggested wounds would have less tension, increased end flap perfusion, and quicker healing. This expectation of the ROM flap, with its low length-to-base ratio and lack of “up-hill” flaps was borne out by the significant reduction in the incidence of end flap necrosis in ROM patients.
Although the trend for ROM patients having lower infection and other complications did not reach statistical significance, they contributed to the overall significantly lower complication rate experienced by ROM patients.
ROM flaps were used to manage larger defects than the non ROM group. The largest ROM defect was 44 mm compared with 31 mm in the non ROM group. The apparent ROM procedure advantage is perhaps further supported by its better results despite this larger defect size range. The ROM procedure was well tolerated with excellent patient acceptance.
As no bleeding complications were experienced in any patient, the policy of not ceasing anticoagulants for this type of surgery is supported. Reduced ambulation following surgery below the knee places patients at increased risk of DVT. Continuing anticoagulant prophylaxis / therapy minimizes such DVT risk.
While no case of DVT was experienced in this series, the early mobilization of patients following ROM closure should theoretically further reduce risk of this complication. A much larger study would be required to identify whether this theoretical reduced DVT risk is realized.
This study has some significant limitations. There was no randomization. This consecutive series involved only one surgeon. As a consecutive series, there is the possibility that improved experience for both surgeon and nursing staff contributed to the better outcomes of ROM cases. As a new procedure, however, the surgeon had no experience with ROM flaps before this study. Further, the surgeon had considerable experience before the first excision in this trial, having excised and closed over 8000 skin lesions prior to the commencement of this study. There were several nursing staff changes over the study period. At all times during the study both, experienced and inexperienced nursing staff was involved in patient management. Although most patients were followed up for many months, not all were available for longer term follow up.
Not all skin cancers below the knee require surgical excision to manage the tumor. Other treatments include; curette (with or without electrodessication), imiquimod ointment, photodynamic therapy and cryotherapy. Further, clinicians can leave post excision wounds to heal by second intention following excision of tumor. Second intent healing can produce excellent results for defects below the knee, but recovery time and time spent with leg elevation can be considerable, with the subsequent disadvantages to patient. ROM flaps enable prompt return to walking and normal activity.
Patients with medium sized defects (11 – 45 mm) below the knees closed with a ROM flap experienced significantly fewer complications than patients with the similar sized defects closed by other means.
In this consecutive series study, end flap necrosis rates were also significantly lower in defects closed with ROM flap versus those closed with other techniques.
Although this study is not randomized, it demonstrates that in the hands of this surgeon, defects below the knee between 11 and 45 mm in size should be closed with a ROM flap hereinafter.
Dermasurgeons should consider adopting this technique.
A future prospective random control trial by other surgeons would further evaluate the role of the ROM flap in closing medium sized elective defects on the leg and foot after skin lesion excision.