The use of botulinum toxin as an adjunct in the treatment of severe congenital unilateral upper limb muscular hypertrophy

Galip Gencay Ustun; Tuzun Firat; Alp Cetin; Ali Emre Aksu

doi:10.4103/tjps.tjps_25_20

CASE REPORT

Year : 2021 | Volume : 29 | Issue : 2 | Page : 128-130

The use of botulinum toxin as an adjunct in the treatment of severe congenital unilateral upper limb muscular hypertrophy

Galip Gencay Ustun¹, Tuzun Firat², Alp Cetin³, Ali Emre Aksu¹
¹ Department of Plastic Reconstructive and Aesthetic Surgery, Faculty of Medicine, Hacettepe University, Ankara, Turkey
² Department of Physical Therapy and Rehabilitation, Faculty of Physical Therapy and Rehabilitation, Hacettepe University, Ankara, Turkey
³ Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Hacettepe University, Ankara, Turkey

Date of Submission 23-Mar-2020

Date of Acceptance 10-May-2020

Date of Web Publication 26-Mar-2021

Correspondence Address:
Dr. Ali Emre Aksu
Hacettepe University Hospitals, Dpt. of Plastic Reconstructive and Aesthetic Surgery, 06100, Altındağ, Ankara
Turkey

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/tjps.tjps_25_20

Abstract

Congenital unilateral upper limb muscular hypertrophy is a rather new entity. Patients have unbalanced muscular forces on their upper extremities due to muscular hypertrophy. These unbalanced forces preclude physiological movements, and in the late course, cause joint deformities. Once joint deformities occur, benefit from surgery diminishes; botulinum toxin can be used for the prediction of a possible benefit from surgery. A 14-year-old girl presented with flexion and ulnar deviation contracture of the left wrist, narrowing of the first web space, flexion contracture of all fingers, and more evident on the first, third, and fourth fingers. After botulinum toxin injection, the most notable benefit was seen on the wrist contracture. In surgery, adductor myotomy, flexor carpi ulnaris transfer to palmar aponeurosis, and tendon transfers of flexor digitorum superficialis to flexor digitorum profundus in the third, fourth, and fifth fingers were made. The postoperative gain was similar to the outcome after botulinum toxin injection. Botulinum toxin may help the surgeon to understand if chronic joint deformities have occurred and predict possible benefit from surgery.

Keywords: Botulinum toxin, congenital unilateral upper limb muscular hypertrophy, joint deformity, muscular hypertrophy, tendon transfers

How to cite this article:
Ustun GG, Firat T, Cetin A, Aksu AE. The use of botulinum toxin as an adjunct in the treatment of severe congenital unilateral upper limb muscular hypertrophy. Turk J Plast Surg 2021;29:128-30

How to cite this URL:
Ustun GG, Firat T, Cetin A, Aksu AE. The use of botulinum toxin as an adjunct in the treatment of severe congenital unilateral upper limb muscular hypertrophy. Turk J Plast Surg [serial online] 2021 [cited 2023 Mar 21];29:128-30. Available from: http://www.turkjplastsurg.org/text.asp?2021/29/2/128/312177

Introduction

Congenital unilateral upper limb muscular hypertrophy (CUULMH) is a rather new entity in the hand surgery literature, which remains a difficult problem for the hand surgeon. Few reports have been published after Mizuoka's original article,^[1] mainly by Japanese authors.^[2],[3],[4] Before diagnosis and treatment planning, one needs to understand CUULMH comprises a broad spectrum of anomalies and is a diagnosis of exclusion. Yet, there are also common features that help the surgeon during differential diagnosis.

These patients have unbalanced muscular forces on their upper extremities due to muscular hypertrophy. These unbalanced forces preclude physiological movements, and in the late course, cause joint deformities. Intermetacarpal widening is a common finding. These are mentally normal patients without associated congenital malformations, except congenital heart defects and torticollis. There is no family history, right/left or gender preponderance noted.^[4] Hypertrophy is more prominent in distal extremity. Flexor and extensor hypertrophy are both reported.^[2],[3]

The treatment strategy is planned on a case basis, as any surgical hand procedure. Contracture releases, muscle excisions, tendon transfers, arthroplasties, and arthrodesis have been suggested in the literature. The goal is to provide intrinsic/extrinsic and flexor/extensor balance in the extremity. Yet, as the disease progresses, chronic joint deformities occur, and even if muscle balance gets provided with surgery, minimal to no benefit is obtained.

Case Report

A 14-year-old girl presented with flexion and ulnar deviation contracture of the left wrist, narrowing of the first web space, flexion contracture of all fingers, and more evident on the first, third, and fourth fingers [Figure 1]. Hand magnetic resonance imaging (MRI) showed advanced contractures and deformities in all fingers and no nerve hamartoma. Before surgery, 100 units of botulinum toxin was applied, with the aid of ultrasound imaging, to superficial, intermediate and deep flexor compartments to relieve muscle spasm. This intervention is thought to help differentiating contracture secondary to muscle spasm from chronic joint deformities. The limited benefit, which was more evident on the wrist contracture, was seen, and the surgery was planned.

Figure 1: Preoperative view of the patient's left upper extremity. Note with flexion and ulnar deviation contracture of the left wrist, narrowing of the first web space, flexion contracture of all fingers, and more evident on the first, third, and fourth fingers

Click here to view

The procedure started with the exploration and tagging of structures under tourniquet control [Figure 2]a. For the narrowing of the first web space, adductor myotomy was performed [Figure 2]b. For wrist contracture, flexor carpi ulnaris (FCU) tendon transfer to palmar aponeurosis was made [Figure 2]c. For finger contractures, needed extra tendon length was gained from transfers of flexor digitorum superficialis to flexor digitorum profundus in the third, fourth, and fifth fingers [Figure 2]d.

Figure 2: Intraoperative view. (a) Exploration and tagging of the median nerve and tendons. Note the pathologic reach of the muscle bellies to the palmar region. (b) Transfer of the third, fourth, and fifth flexor digitorum superficialis tendons to flexor digitorum profundus tendons. Note the increase in extension capacity. (c) Myotomy of adductor pollicis brevis muscle. (d) Transfer of flexor carpi ulnaris tendon to palmar aponeurosis

Click here to view

For the fingers, early active mobilization protocol was started to prevent adhesions, immediately after the surgery. The wrist was kept in a neutral position, and thumb in palmar abduction for 4 weeks to prevent contracture recurrence. Postoperative pinch and grip can be seen in [Figure 3]a and [Figure 3]b.

Figure 3: Postoperative view. (a) Fine motor pinch ability. (b) Grasping ability

Click here to view

Discussion

CUULMH is a rare phenomenon in hand surgery, which includes both mild and severe anomalies. There is some controversy in nomenclature. Even though the name of this deformity contains “unilateral,” Ogino et al.^[5] reported a patient with bilateral deformity and used “aberrant muscle syndrome” term, but in this report, it will be referred to as CUULMH due to its widespread use in the literature. In CUULMH, flexion or extension contractures, ulnar drift of the fingers/wrist, and intermetacarpal widening can be seen in varying degrees.

The etiology of this deformity remains to be unknown, but theories had been put forward to date. Tanabe et al. claim that laxity of the transverse metacarpal ligaments is the underlying etiology of this condition. Even if this theory explains the common intermetacarpal widening feature, it does not clarify the muscular hypertrophy. Takka et al. claim that multiple neuromuscular innervation causes longitudinal hypertrophy of muscles and emphasizes the changed tendon to muscle ratio that can be seen in these patients, but neither histologic nor electromyographic analysis was made in their article.^[4] A relatively new article by Castiglioni et al. found and association with PIK3CA mutation in a 6-year-old girl, which is the only nonspeculative data to date.^[6]

As mentioned, as a diagnosis of exclusion, some entities need to be excluded in the diagnosis process. Proteus syndrome can be excluded with lack of excessive bone hypertrophy, progressive course, and lower extremity involvement; macrodactyly can also be excluded with lack of excessive bone hypertrophy and isolated finger involvement; Freeman–Sheldon syndrome, a type of distal arthrogryposis can be excluded with lack of microstomia, whistling face, and H-shaped chin dimple; and nerve hamartomas can be excluded using MRI.

As muscular hypertrophy, first reports suggested muscle excisions for functional and cosmetic purposes, but results were not satisfactory.^[2] Determining the excision amount of aberrant muscles is difficult, and the procedure may cause another imbalance. Arthroplasties are useful for joint deformities, but the little benefit can be gained, and the patient selection and informing are essential. Arthrodesis is the late solution for chronic deformities. Tendon transfers are relatively easy procedures that aid in restoring the balance without associated morbidity.

Botulinum toxin use has not been reported in the literature for the treatment of CUULMH. Botulinum toxin use can help differentiate muscle imbalances from chronic joint deformities. There is no guideline or specific dosing scheme for the use of botulinum toxin for contractures caused by CUULMH. However, botulinum toxin is widely used for patients with spastic cerebral palsy.^[7] The recommended dose for forearm muscles is 1–2 U/kg/muscle whereas 0.5–1 U/kg/muscle for intrinsic hand muscles.^[8] One needs to keep in mind that these muscles are pathologically hypertrophic muscles, and routine dosage may not be adequate for these patients. However, the maximum dosage per injection should be limited to 8–10 U/kg/muscle or 400 U. Hence rather than injecting to every muscle belly, injections to specific muscles may need to be done to increase effectiveness while minimizing toxicity. Authors think botulinum injection 4–8 weeks before planned surgery is the optimal timing for the evaluation of effect. In our case, more relaxation was gained in the wrist contracture, so FCU transfer was made to restore balance in the wrist. However, little difference was noted in fingers. During exploration, shortening of flexor tendons was noted, which precluded passive extension, and transfers were made to elongate these tendons.

At the point where botulinum toxin does not work, the following question comes to our mind, what shall we do? Well, the inefficacy of botulinum toxin shows chronic joint deformities have occurred, and tendon transfers would have less benefit. Arthroplasties or arthrodesis are treatment options to overcome these deformities. However, it should be kept in mind that the benefits that can be obtained from these procedures can be quite limited. Tendon transfers may be the next step after releasing joint contractures, but the passive motion of relevant joints must be maximized beforehand.

Although there is a paucity of treatment suggestions for CUULMH, none of these procedures proved itself the righteous one for these patients. Most of the patients in the literature and nearly all of the patients with a severe deformity have unsatisfactory results. For this reason, patients need to understand multiple operations to be done in this long path, and gain may not be much in the end. Our patient is able to have a broader grip, but we were unable to improve fine motor movements of fingers, possibly due to chronic joint deformities.

For the future perspective, we think shedding light on the etiology may change the game. Etiology remains to be unknown, and most of the literature says its “idiopathic.” Today, we still do not know the pathology and treat the result, which is merely adequate. Genetic research is continuing, and hopefully, in the near future, we will be able to come up with the answer directed at the cause, not the result of this deformity.

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.

References

1.	Mizuoka JH, Ohmiya K. Duplication of thenar and hypothenar muscles in a incestuous offspring: A case report. Seikeigeka 1962;13:963-5.
2.	Tanabe K, Tada K, Doi T. Unilateral hypertrophy of the upper extremity due to aberrant muscles. J Hand Surg Br 1997;22:253-7.
3.	Imai S, Isoya E, Kubo M, Kodama N, Matsusue Y. Congenital unilateral upper limb muscular hypertrophy associated with contracture of an extrinsic extensor tendon. J Hand Surg Eur Vol 2007;32:308-10.
4.	Takka S, Doi K, Hattori Y, Kitajima I, Sano K. Proposal of new category for congenital unilateral upper limb muscular hypertrophy. Ann Plast Surg 2005;54:97-102.
5.	Ogino T, Satake H, Takahara M, Kikuchi N, Watanabe T, Iba K, et al. Aberrant muscle syndrome: hypertrophy of the hand and arm due to aberrant muscles with or without hypertrophy of the muscles. Congenit Anom (Kyoto) 2010;50:133-8.
6.	Castiglioni C, Bertini E, Orellana P, Villarroel C, Las Heras F, Hinzpeter D, et al. Activating PIK3CA somatic mutation in congenital unilateral isolated muscle overgrowth of the upper extremity. Am J Med Genet A 2014;164A: 2365-9.
7.	Multani I, Manji J, Hastings-Ison T, Khot A, Graham K. Botulinum toxin in the management of children with cerebral palsy. Paediatr Drugs 2019;21:261-81.
8.	Yadav S, Chand S, Majumdar R, Sud A. Effect of botulinum toxin type-A in spasticity and functional outcome of upper limbs in cerebral palsy. J Clin Orthop Trauma 2020;11:208-12.