Lumps, bumps, and…nerve-end stumps? A collection of guidelines for safe in-office lipoma excision

ABSTRACT

Lipomas are benign adipose tumors frequently encountered by the primary care physician. They are the most common soft tissue tumor diagnosed in the adult population and generally present as soft, round, and discrete masses located in the subcutaneous tissues of nearly any anatomical location. In-office excision has become common practice, however, limitations of such settings along with varying locations and presentations of these lipomas may render the patient more susceptible to complications. This manuscript aims to provide the general practice provider with a set of safety guidelines for in-office lipoma excision, thus decreasing the chance of major complications. These guidelines include: obtaining a clear diagnosis prior to excision, ensuring familiarity with the anatomical location prior to excision, deferring excision if the lipoma appears to be located in the subfascial plane, and aborting excision if the patient is at risk for local anesthetic toxicity, if symptoms of motor blockade develop, or if uncontrolled bleeding occurs. The importance of these guidelines is highlighted by a case report of radial nerve injury sustained during an in-office lipoma excision requiring operative reconstruction of the radial nerve.

Introduction

Lipomas are benign adipose tumors frequently encountered by the primary care physician. Though these growths are rarely symptomatic, patients desire removal for a variety of reasons.[1] Lipomas may be found in nearly any anatomical location, however, are most frequently located in the subcutaneous tissue making in-office excision common practice.[2-6] Due to limitations of the in-office setting such as inconsistent access to electrocautery, suboptimal lighting, and reliance on local anesthesia, the risk of serious complications exists. Hematoma formation and nerve injury have been reported to occur in 1.6% and 0.8% of patients.[1] We present a collection of clinical guidelines for the avoidance of major complications during in-office lipoma excision. The importance of these guidelines is highlighted by a case report of radial nerve transection causing wrist drop during an in-office lipoma excision.

Case Report

An adult male was seen by his primary care physician for evaluation of a left upper extremity lump. The patient was clinically diagnosed with a lipoma and underwent in-office excision of the mass under local anesthetic. During the procedure, the patient developed acute radial nerve palsy. These symptoms were initially thought to be secondary to the use of local anesthetic or traction on the nerve caused by pulling on the mass during excision. The patient then presented to the emergency department the following day with complaints of persistent wrist drops. At that time, an orthopedic hand specialist evaluated the patient. Concern for radial nerve injury and hematoma prompted exploration of the wound in the operating room where a 100 cc hematoma was evacuated. The excisional cavity tracked down to bone and the radial nerve was found to be transected with a resultant four-centimeter gap after debridement and mobilization of the nerve-end stumps. The nerve was reconstructed with nerve autograft [Figures 1 and 2]. Given the patient’s level of injury, full recovery to premorbid strength is unlikely.[7-9] This case highlights the importance of adhering to surgical safety principles when conducting an in-office lipoma excision to decrease the risk of major complications. These surgical safety principles are detailed below.

Figure 1.

Operative exploration of the previous in-office lipoma excision cavity with demonstration of a 4 cm gap in the radial nerve

Figure 2.

Radial nerve reconstruction completed with a six-strand sural nerve cable autograft harvested from the patient’s left lower extremity

Discussion

To limit the risk of major complications during in-office lipoma excision, we have provided a collection of surgical safety principles pertaining to diagnosis, location, administration of local anesthetic, and surgical technique.

Most lipoma diagnoses can be made clinically, however, masses greater than 5 cm, and those with a rapid rate of growth should be evaluated with magnetic resonance imaging (MRI) for further characterization.[10,11] If the clinical diagnosis is not clear, the clinician should not pursue in-office excision. Further imaging, pathological sampling via biopsy, or specialty consultation may be employed for the determination of diagnosis prior to excision.

Most frequently, lipomas are located in the subcutaneous plane making in-office excision a safe option in many cases. However, the subcutaneous location of a lipoma does not guarantee risk-free excision, as even these lipomas may lie in close proximity to major motor nerves in areas such as the face, elbow, volar forearm, and posterior knee. The clinician should evaluate their own level of comfort and familiarity with the pertinent anatomy surrounding any lipoma planned for excision and defer excision when unfamiliar with the local anatomy or if uncertain as to the location or depth of the mass. Intramuscular or subfascial lipomas will move with muscle activation, whereas superficial, subcutaneous lipomas will remain free and mobile with muscle activation.[10] If the lipoma appears to be located in the subfascial plane, defer in-office excision as a risk for complications such as bleeding or nerve damage increases.

Knowledge of safe weight-based local anesthetic dosing is essential for in-office procedural care to avoid significant complications.[12] If the lipoma is large or located in an area that may require toxic dosages of local anesthesia for adequate pain relief, the procedure should be aborted. For motor blockade to occur, local anesthetic must be administered in such close proximity to the motor nerve, that any motor impairment following the administration of the local anesthetic should raise concern.[13] This should indicate to the physician that the lipoma is located too close to a major peripheral motor nerve for safe removal in the in-office setting and excision should be deferred. Similarly, if the patient develops motor impairment during the procedure, this likely indicates nerve injury and a surgical specialist should be contacted immediately.

Though varying techniques for lipoma excision have been described in the literature, we advocate for the use of a longitudinal incision without elliptical skin excision.[1,14,15] Excision of skin for lipoma removal is not indicated as excess skin almost always flattens over time. Skin closure completed under tension as a result of unnecessary skin excision places the patient at risk for complications such as dehiscence and widened scar formation. Once the dermis has been sharply incised, the skin should be retracted allowing direct visualization of the lipoma. Dissection should then be completed bluntly via spreading motions made circumferentially along the lipoma capsule with tenotomy scissors. This allows the safe separation of the lipoma from the surrounding tissues. After the lipoma has been freed from all surrounding tissues, the lipoma can then be dissected from the stalk with the use of either electrocautery or tenotomy scissors. Electrocautery should be completed under direct visualization with care taken to ensure no thermal injury to the skin or deeper structures occurs. The specimen should be sent for pathological evaluation and the wound irrigated and inspected for hemostasis. Skin closure should be achieved in layers with the clinician’s choice of absorbable suture for deep dermal closure and either absorbable or nonabsorbable suture for fine skin approximation.

If the dissection extends deep to the fascial plane, the clinician should abort the procedure due to the increased risk of complications. The provider should defer deeper dissection, obtain hemostasis, and close skin. Specialty consultation should be obtained for evaluation and definitive surgical excision of the mass.

No procedure exists without risk, however, these guidelines aim to provide the clinician with safety practices that may minimize the risk of major complications during in-office lipoma excision [Table 1].

Table 1.

Surgical Safety Principles for In-office Lipoma Excision

Principle	Description
Diagnosis	If diagnosis based on history and physical exam is not clearly established, do not excise the mass. Opt for clarification with imaging, pathology, or specialist consultation.
Evaluation of Location	If the clinician is uncomfortable with the relevant anatomy surrounding the lipoma, or if the lipoma appears to be located in the subfascial or intramuscular plane, defer in-office excision.
Administration of Local Anesthetic	If administration of local anesthetic results in motor deficit, do not proceed with excision. If motor deficit occurs mid-procedure, contact a surgical specialist for immediate evaluation.
Operative Technique	If significant skin excess is expected, do not excise skin with initial incision. Allow excess skin to flatten over time to avoid complications such as dehiscence or widened scar formation. Utilize blunt dissection conducted closely to the capsule of the lipoma. This helps to avoid inadvertent injury and trauma to the surrounding tissues and structures.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.