Abstract
A lipoma, which is composed of fatty tissue, is the most common benign soft-tissue tumor. Lipomata can develop anywhere in the body including the intermetatarsal space. The intermetatarsal space is filled by dorsal and plantar interossei muscles, and a lipoma in this space will extend outside this space as the tumor grows. Classically, lipoma is resected via an open approach, which may result in a lengthy disfiguring surgical scar. The purpose of this Technical Note is to describe the details of endoscopic en bloc resection of intermetatarsal lipoma. This minimally invasive approach can provide a whole block specimen for histologic examination and reduce tumor seeding as compared with endoscopic piecemeal resection of lipoma.
Technique Video
A lipoma, which is composed of fatty tissue, is the most common benign soft-tissue tumor.1,2 Lipomata can develop anywhere in the body including the intermetatarsal space.1, 2, 3, 4, 5, 6, 7, 8 The intermetatarsal space is filled by dorsal and plantar interossei muscles, and a lipoma in this space will extend outside this space as the tumor grows. The patient may complain of cosmetic concerns and/or irritation with when wearing shoes.8 The tumor may also impinge the cutaneous nerve, causing numbness or paresthesia of the forefoot dorsum.
Classically, lipoma is resected via an open approach, which may result in a lengthy disfiguring surgical scar. Endoscopic en bloc tumor resection is a minimally invasive approach and can provide a whole block specimen for histologic examination.1,3,9,10
The purpose of this Technical Note is to describe the details of endoscopic en bloc resection of intermetatarsal lipoma. It is indicated in intermetatarsal lipoma extended dorsally through the inferior extensor retinaculum. It is contraindicated if it is a case of liposarcoma or the lipoma extended plantarly and proximally underneath the tarsal bones which requires open resection (Table 1).11,12
Table 1.
Indications and Contraindications of Endoscopic En Bloc Resection of Intermetatarsal Lipoma
| Indications | Contraindications |
|---|---|
|
|
Surgical Technique
Preoperative Assessment and Patient Positioning
Any clinical evidence of impingement of adjacent nerves and tendons by the tumor should be documented. Preoperative magnetic resonance imaging is an important investigation to study the nature of the tumor and its location and relationship to adjacent anatomical structures (Fig 1).
Fig 1.
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in the supine position with the legs spread. Magnetic resonance imaging of the illustrated case shows the intermetatarsal lipoma extended dorsally to the subcutaneous plane. Sagittal images (A-B); coronal images (C-D). (L, lipoma.)
The patient is placed in the supine position with the legs spread. A thigh tourniquet is applied to provide a bloodless operative field. A 2.7-mm 30° arthroscope (Henke Sass Wolf GmbH, Germany) is used for this procedure. Fluid inflow is by gravity and arthro-pump is not used.
Portal Placement
This procedure is performed via the distal and proximal lateral portals, which are at the distal corner and proximal lateral corners of the tumor (Fig 2). The distal portal should be placed over the intermetatarsal space from which the lipoma comes. Placing the proximal portal at the side of the lipoma can avoid hindrance of instrumentation freedom by the leg.
Fig 2.
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in supine position with the legs spread. This procedure is performed via the distal and proximal lateral portals which are at the distal corner and proximal lateral corners of the tumor. (DP, distal portal; L, lipoma; PLP, proximal lateral portal.)
Dissection of the Distal Part of the Lipoma
The proximal lateral portal is the viewing portal, and the distal portal is the working portal. The soft tissue is stripped from the surface of the fibrous capsule of the lipoma by a hemostat and an arthroscopic shaver (DYONICS; Smith & Nephew, Andover, MA). The fibrous capsule is released with a retrograde knife (Smith & Nephew) to expose the lipoma. The lipoma is dissected from the fibrous capsule and the underlying interossei muscles by peanut swab, hemostat, and SuperCut scissors (Stille, Lombard, IL) (Fig 3).
Fig 3.
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in supine position with the legs spread. (A) The proximal lateral portal is the viewing portal, and the distal portal is the working portal. (B) Soft tissue is stripped from the surface of the fibrous capsule of the lipoma by an arthroscopic shaver. (C) The fibrous capsule is released with a retrograde knife to expose the lipoma. (D) The lipoma is dissected from the fibrous capsule by peanut swab. (AS, arthroscopic shaver; DP, distal portal; FC, fibrous capsule of the lipoma; L, lipoma; PLP, proximal lateral portal; PS, peanut swab; RK, retrograde knife.)
Dissection of Proximal Part of the Lipoma
The distal portal is the viewing portal, and the proximal lateral portal is the working portal. The lipoma is traced proximally, and the extensor tendons and inferior extensor retinaculum are identified. The retinaculum is release from its distal edge proximally by the retrograde knife. The site where the lipoma herniated through the extensor retinaculum can then be identified. The retinaculum is further released with the SuperCut scissors so the constriction between the superficial and deep parts of the lipoma is completely released (Fig 4). The distal portal incision is enlarged and the whole lipoma can be removed via this portal (Fig 5, Video 1).
Fig 4.
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in supine position with the legs spread. (A) The distal portal is the viewing portal, and the proximal lateral portal is the working portal. (B) The lipoma is traced proximally, and the extensor tendons and inferior extensor retinaculum are identified. The retinaculum is release from its distal edge proximally by a retrograde knife. (C) The site where the lipoma herniated through the extensor retinaculum can then be identified. (D) The retinaculum is further released with a SuperCut scissors so the constriction between the superficial and deep parts of the lipoma is completely released. (DP, distal portal; ET, extensor tendon; IER, inferior extensor retinaculum; PLP, proximal lateral portal; L, lipoma; Ld, deep part of the lipoma; Ls, superficial part of the lipoma; RK, retrograde knife; S, scissors.)
Fig 5.
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in supine position with the legs spread. The distal portal incision is enlarged and the whole lipoma can be removed via this portal. (L, lipoma; PLP, proximal lateral portal.)
Discussion
In contrast to piecemeal removal of lipoma, endoscopic en bloc excision of the whole lipoma provides a better specimen for pathohistologic examination and reduces the risk of seeding of residual tumor.1,3,9,10
This endoscopic technique is not technically difficult. The key of success is detailed preoperative planning with the findings of magnetic resonance imaging, including the extent of the lipoma and identifying the structures encased by the lipoma, and proper placement of the portals (Table 2).
Table 2.
Pearls and Pitfalls of Endoscopic En Bloc Resection of Intermetatarsal Lipoma
| Pearls | Pitfalls |
|---|---|
|
|
The advantages of this technique include small incisions and better cosmetic outcome, minimal soft-tissue trauma, and en bloc resection of the lipoma. The potential risks of this technique include incomplete resection of the lipoma, injury to the extensor tendons, deep peroneal nerve and branches of the superficial peroneal nerve, and incompetence of the inferior extensor retinaculum and subtalar instability (Table 3).
Table 3.
Advantages and Risks of Endoscopic En Bloc Resection of Intermetatarsal Lipoma
| Advantages | Risks |
|---|---|
|
|
Disclosures
All authors (T.H.L., K.K.C., O.T.S.H.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Supplementary Data
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in the supine position with the legs spread. The proximal lateral portal is the viewing portal and the distal portal. The initial endoscopic working area is created just superficial to the fibrous capsule of the lipoma. The fibrous capsule is incised open to expose the lipoma. The lipoma is dissected from the fibrous capsule and underlying interossei muscles. The arthroscope is then switched to the distal portal. The lipoma is traced proximally to identify the extensor tendon and inferior extensor retinaculum. The retinaculum is released to expose the area where the lipoma herniated through the retinaculum. The constriction between the superficial and deep parts of the lipoma is released and whole lipoma is extracted via the distal portal.
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Associated Data
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Supplementary Materials
Endoscopic en bloc resection of intermetatarsal lipoma of the left foot. The patient is in the supine position with the legs spread. The proximal lateral portal is the viewing portal and the distal portal. The initial endoscopic working area is created just superficial to the fibrous capsule of the lipoma. The fibrous capsule is incised open to expose the lipoma. The lipoma is dissected from the fibrous capsule and underlying interossei muscles. The arthroscope is then switched to the distal portal. The lipoma is traced proximally to identify the extensor tendon and inferior extensor retinaculum. The retinaculum is released to expose the area where the lipoma herniated through the retinaculum. The constriction between the superficial and deep parts of the lipoma is released and whole lipoma is extracted via the distal portal.