*Author for correspondence. Email:
david.angelo@ipface.pt |
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David Faustino Ângelo |
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1Instituto Português da Face, Lisboa, Portugal
2Centre for Rapid and Sustainable Product Development,
Polytechnic Institute of Leiria, Portugal 3Faculdade de
Medicina da Universidade de Lisboa, Portugal
4Serviço de Estomatologia Hospital Egas Moniz – Unidade
Local de Saúde Lisboa Ocidental, Portugal 5Clínica
Universitária de Estomatologia, Unidade Local de Saúde Santa
Maria, Lisboa, Portugal Unilateral condylar hyperactivity (UCH) has many
different definitions in the literature [1–3]. Still, one of
the most encompassing definitions describes it as a
condition with increased bone-cell activity of one
mandibular condyle, resulting in growth-resembling
progressive mandibular asymmetry of unknown etiology
occurring over an uncertain period of time and at an
uncertain rate in patients with varying age ranges, lacking
a gold standard [4]. Dr. Robert Adams lived between 1791 and
1875 and, to our knowledge, was the first to describe a UCH
in a female patient (Mary Keeve). In the literature and
clinical discussions, it is very common to observe confusion
between (1) condylar hyperactivity, (2) condylar
hyperplasia, (3) condylar hypertrophy, and (4)
hypermetabolic condyle. Condylar hyperactivity suggests an
increased growth regardless of size, and it’s a dynamic term
[5]; Condylar hyperplasia means an increase in cell number,
ongoing mitosis and a static end stage [6]. Condyle
hypertrophy implies an increase in cell size, no mitosis and
static end stage. Hypermetabolic condyle suggests an
abnormal hypermetabolic growth centre, but it’s not a
histological term. To use the correct terminology, we should
use hyperactivity, usually the primary cause, and
hyperplasia, usually secondary to the hyperactivity.
Condylar hyperactivity means a growing condyle; size does
not matter – the condyle is actively growing. |
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During the last few years, different classifications have been
proposed for UCH. Obwegeser and Makek proposed three types:
hemimandibular hyperplasia (HH), hemimandibular elongation (HE) and
hybrid forms [1]. A special remark for the term hyperplasia and not
hyperactivity. A recent study from Gateno
Nitzan
which is unilateral with normal condyle architecture but an enlarged head. Growth (unknown cause) with potentially ongoing growth into adulthood, and type 1B, mas/osteomas; CH type 4: malignant tumours originating in the condyle. Type
is usually self-limited. This system helps diagnose condylar hyperplasia and guide the treatment based on the underlying histopathological cause and growth pattern [3].
Further, the Wolford classification system categorised conditions causing condy-lar hyperplasia, defined as an abnormal enlargement of the jaw condyle. It pri-oritises by frequency: CH type 1, unilateral or bilateral excessive growth of the condyle; CH type 2: unilateral overgrowth due to benign tumours like osteochon-dromas or osteomas; CH type 3: rare benign tumours other than osteochondro-
2 David Faustino Ângelo
Please note how, in the classifications, the word used is hyperplasia and not hyperactivity.
Within the classification of condylar pathologies, mandibular condyle hyper-plasia takes the centre stage. However, hyperactivity of the condyle becomes paramount in establishing a diagnosis and selecting the most appropriate treat-ment course. For when the condyle is “active”, the surgical goal is to turn it off, removing the abnormally active growing centre. Current evidence suggests that SPECT scans are the most reliable diagnostic tool to detect condylar hyperactiv-ity. A positive scan with progressive facial asymmetry warrants a condylectomy. Conversely, a positive scan without progression may indicate a watchful waiting approach to be more prudent. Orthognathic surgery is recommended in the case of a negative scan but with present facial asymmetry. The terminology surrounding treatment options can be a source of confusion as well. To clarify:
• Condylectomy: this surgical technique involves an osteotomy (bone cut) performed at the level of the sigmoid notch, followed by the removal of the condyle’s head and neck.
• Condylar Shaving: this procedure removes a limited amount (2-3mm) of the condylar surface, specifically targeting the fibrocartilage.
• Condylar Reduction: this technique removes a more substantial portion (5-6mm) of the condylar surface. It is the preferred treatment for unilateral condylar hyperplasia (UCH).
While some surgeons may mistakenly use the term "condylectomy" for condylar reduction, it is crucial to maintain accurate terminology for clarity. Recently, TMJ surgeons have implemented different types of condylectomy, such as guided pro-portional condylar reduction [8] or slice functional technique, where the amount of bone to be removed is planned previously. This technical modification aims to equalise the healthy and unhealthy condyles, removing either a single piece or small slices [9] . The advent of 3D planning technology has also brought signifi-cant innovations in this field, making condylectomy techniques less invasive and more predictable. To improve the treatment accuracy, the ultimate technique is to perform an intraoral guided proportional condylar reduction [10] . A 3D-printed custom-made cutting guide laying over the sigmoid notch creates a glide plane for oscillating/piezoelectric tools, making the procedure easier.
In conclusion, unilateral condylar hyperactivity (UCH) presents a complex and evolving field of study, marked by a mare magnum of definitions, classifications, and treatment approaches. Despite the frequent misunderstanding between terms such as condylar hyperactivity, hyperplasia, and hypertrophy, understanding the nuances of each is crucial for accurate diagnosis and effective treatment. The ad-vancements in classification systems—from Obwegeser and Makek’s to the Wolford system—have significantly improved our ability to categorize and manage UCH. Surgical interventions like the proportional condylar reduction, particularly when guided by advanced imaging techniques, offer promising outcomes for patients with mandibular asymmetry. While challenges remain, particularly in termino-logical clarity and treatment precision, the integration of modern technology like 3D planning is enhancing surgical accuracy and in experienced hands to perform an intraoral approach. Ultimately, individualized treatment, based on a thorough diagnostic process, remains key to addressing condylar hyperactivity and restoring facial symmetry for affected patients.
[1] Obwegeser, H.L.; Makek, M.S. Hemimandibular hyperplasia–
hemimandibular elongation.
[2] Nitzan, D.W.; Katsnelson, A.; Bermanis, I.; Brin, I.; Casap, N.
The clinical characteristics of condylar hyperplasia: experience with
61 patients.
[3] Wolford, L.M.; Movahed, R.; Perez, D.E. A classification system
for condi-tions causing condylar hyperplasia.
[4] Arora, K.S.; Bansal, R.; Mohapatra, S.; Pareek, S. Review and
Classification Update: Unilateral condylar hyperplasia.
[5] Ghawsi, S.; Aagaard, E.; Thygesen, T.H. High condylectomy for
the treatment of mandibular condylar hyperplasia: a systematic review
of the literature.
[6] Nolte, J.W.; Alders, M.; Karssemakers, L.H.E.; Becking, A.G.;
Hennekam, R.C.M. Molecular basis of unilateral condylar hyperplasia?
[7] Gateno, J.; Coppelson, K.B.; Kuang, T.; Poliak, C.D.; Xia, J.J.
A better under-standing of unilateral condylar hyperplasia of the
mandible.
[8] Sembronio, S.; Tel, A.; Costa, F.; Robiony, M. An updated
protocol for the treatment of condylar hyperplasia: Computer-guided
proportional condylec-tomy.
[9] Cascone, P.; Runci Anastasi, M.; Maffia, F.; Vellone, V. Slice
Functional Condylectomy and piezosurgery: A proposal in unilateral
condylar hyper-plasia treatment.
[10] Haas Junior, O.L.; Fariña, R.; Hernández-Alfaro, F.; de
Oliveira, R.B. Minimally invasive intraoral proportional condylectomy
with a three- dimensionally printed cutting guide.