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\begin{document}

\title{Large Sternal Exostoses presenting as stridor: A Surgical and Anesthetic
challenge}



\author[1]{Alok Sharma}%
\author[1]{Surendra Patel}%
\author[1]{Danishwar Meena}%
\author[1]{Ranjit Sahu}%
\author[1]{Amit Goyal}%
\author[1]{Pawan Garg}%
\author[1]{Mritunjay Kumar}%
\affil[1]{All India Institute of Medical Sciences Jodphur}%


\vspace{-1em}



  
  \date{May 04, 2024}


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\selectlanguage{english}
\begin{abstract}
Large osteochondroma arising from chest wall and sternum is uncommon and
presentation with airway compression is further uncommon. Here we
present a case of large chest wall osteochondroma as a part of
Hereditary multiple exostoses in a 9 years old boy presented with a
history of stridor and shortness of breath. The bony mass of the right
chest wall was extending up to a suprasternal notch and compressing the
trachea. The case was successfully managed by initial femoro-femoral
cardiopulmonary bypass under local anesthesia prior to the induction of
anesthesia to prevent respiratory collapse, followed by debulking
surgery was done.%
\end{abstract}%



\sloppy




\textbf{Introduction}

Hereditary multiple exostoses (HME) is an autosomal dominant disease
characterized by abnormal growth of bones, mainly involving epiphyses of
long bones. In HME involvement of Sternum is very
rare\textsuperscript{1}. Large sternal mass compressing airway needs to
be managed by a multidisciplinary approach to prevent injury to great
vessels, heart, and risk of fatal respiratory failure during induction
of anesthesia. We are reporting this case due to a very rare
presentation of a large sternal exostoses compressing airways, which was
managed successfully.

\textbf{Case report}

A 9 years old male child presented with complaints of rapidly
progressive shortness of breath for the last 2 months more on supine
position. The patient had a history of progressively increasing
swellings in upper limbs, lower limbs, and chest wall since the age of 2
years. The patient had a large, irregular, bony-hard, swelling involving
Upper 2/3 of sternum, suprasternal notch and right shoulder.
{[}fig.1{]}. The bony mass over suprasternal notch was compressing the
cervical part of the trachea, causing stridor. The swellings of
extremities were of cosmetic concerns only. The father of the patient
also had bony swellings over the right humerus and left femoral bone.
Computed tomography (CT) of the thorax showed a large exophytic bony
mass involving sternum and right side of chest wall {[}Fig 2A, 2B, 2C,
3A, and 3B{]}. The mass was encroaching in suprasternal notch causing
compression of the trachea at the level of lower border of C7 vertebra.
The minimum anteroposterior diameter of the trachea was 3.4 mm {[}Fig.
2D{]}. Multiple other bony exostoses also have seen arising from ribs
{[}Fig 2C{]} and scapula.

The key challenge in this patient was the severe external compression of
the trachea, not permitting the minimum required size of the
endotracheal tube. The case was discussed by the multidisciplinary
team\textbf{.} Considering the above circumstances, it was decided to
perform femoro-femoral Cardiopulmonary Bypass (CPB) under local
anesthesia preceding the induction of general anesthesia (GA). Various
invasive lines were placed under local anesthesia (LA) for
intraoperative monitoring after verbally explaining to the patient. The
right femoral artery and vein were exposed under LA and were canulated
with 16 and 20 Fr sized canula (Edwards FemFlex\selectlanguage{ngerman}®) respectively.
Cardiopulmonary bypass (CPB) was established at 80\% flow. After that
Anaesthesiologists induced the patient and put Flexo-metallic
endotracheal tube (ET tube) 4 mm size using a fiber-optic laryngoscope
and later, it was exchanged with 5.5 mm using a tube-exchanger. After
confirmation of good ventilation via the ET tube, CPB was weaned. The
total CPB time was 85 minutes.

A 'T' shaped incision was given over swelling with transverse limb at
the level of the thyroid cartilage and the vertical limb extending up to
xiphisternum. The~ bony-mass was removed in piecemeal by using chisel,
hammer, and oscillating saw while taking care of major neck vessels and
trachea. While the suprasternal extension of mass was completely
removed, only debulking of sternal body and chest wall mass were done to
achieve fair cosmetics result. No evidence of tracheomalacia was found.
In view of uneventful post-operative recovery, and absence of any
residual respiratory difficulty, the patient was discharged on the
fourth postoperative day. Histopathology report was suggestive of
Osteochondroma. CT thorax done at one-month follow-up showed an adequate
debulking of mass {[}Fig 3C, 3D{]} with the normal trachea. The patient
was asymptomatic and aesthetically satisfied after 1 year.

\textbf{Discussion}

Osteochondroma (Exostoses) is the commonest benign bone
tumor\textsuperscript{2}. These are cartilage-capped bony projections
arising on the external surface of the bone and containing a marrow
cavity that is continuous with that of the underlying
bone\textsuperscript{3}. The majority of lesions are solitary, and
around 15\% are multiple as a part of Hereditary multiple exostoses
(HME) syndrome. The patient usually presents in childhood with bony
swelling in limbs, causing deformity, and sometimes symptoms related to
compression of surrounding structures. Around 50\% of patients present
by the age of 5 years and 80\% by 10 years of age\textsuperscript{1}.
Our patient had multiple large swelling over upper limbs, lower limbs,
and chest wall since the age of 2 years, which were gradually increasing
in size. He presented with difficulty in breathing and stridor on supine
position due to compression of trachea by large suprasternal exostoses
mass. The patient's father also had similar bony swellings over limbs,
which supports our diagnosis of Hereditary multiple exostoses (HME).

The use of extracorporeal circulation in management of airway
obstruction was first reported by Onozawa et al in 1999, in a patient
with thyroid carcinoma\textsuperscript{4}. The use of CPB before
induction of GA for surgeries of large neck or mediastinal masses
compressing airways has been reported\textsuperscript{5,6}. With the
induction of GA, there is a loss of respiratory muscle tone and decrease
functional residual capacity which in patients with already compromised
airways may lead to respiratory collapse and death\textsuperscript{6}.
The tip of the ET tube can injure our patient's trachea at the site of
maximal compression leading to catastrophe.

We have managed our case successfully while avoiding catastrophic events
by instituting femoro-femoral CBP under LA preceding to the induction of
GA.

\textbf{Conclusion}

In patients of compromised airways due to compression by surrounding
tumors/ masses, femoro-femoral cardiopulmonary bypass is a safe method
to prevent further airway compromise while induction of
anesthesia\textbf{.}









\textbf{References}

\begin{enumerate}
\tightlist
\item
  Ryckx A, Somers JF, Allaert L. Hereditary multiple
  exostosis.\emph{Acta Orthop Belg.} 2013;79(6):597--607.
\item
  Murphey MD, Choi JJ, Kransdorf MJ et al. Imaging of osteochondroma:
  variants and complications with radiologic-pathologic
  correlation.\emph{Radiographics.} 2000;20:1407-1434.
\item
  Khurana J, Abdul-Karim F, and Bovée JVMG: Osteochondroma. In: Fletcher
  CDM, Unni KK, and Mertens F, eds. \emph{World Health Organization
  Classification of Tumours. Pathology and Genetics of Tumours of Soft
  Tissue and Bone.} Lyon, France: IARC; 2002:234-236
\item
  Onozawa H, Tanaka T, Takinami M, Kagaya S, Tanifuji Y. Anesthetic
  management using extracorporeal circulation of a patient with severe
  tracheal stenosis by thyroid cancer (Japanese).
  Masui.1999;48(6):658-61
\item
  Tempe DK, Arya R, Dubey S, Khanna S, Tomar AS, Grover V, Nigam M,
  Makwane UK. Mediastinal mass resection: femorofemoral cardiopulmonary
  bypass before induction of anesthesia in the management of airway
  obstruction. \emph{J Cardiothorac Vasc Anesth.} 2001;15:233--6.
\item
  Kim CW, Kim DH, Son BS, et al. The Feasibility of Extracorporeal
  Membrane Oxygenation in the Variant Airway Problems. \emph{Ann Thorac
  Cardiovasc Surg} . 2015; 21(6):517\selectlanguage{english}-522.
\end{enumerate}





\textbf{Figure captions}

Figure. 1: A large, irregular, swelling involving Upper 2/3 of sternum
extending to suprasternal notch (blue arrow) and right shoulder.

Figure 2: Computed tomography (CT) of the thorax in axial (A) (B) and
coronal (C) and Sagittal (D) plane, showing large exophytic bony mass
(black Asterisk) arising from the right side of the chest wall. The mass
is causing compression over the airway resulting in severe narrowing of
the trachea (minimal diameter of 3.4 mm) (white arrow). Multiple other
bony exostoses arising from ribs (dashed arrow).

Figure 3: Volume rendered (VR) 3D images of the chest in coronal (A) and
oblique plane (B), showing large bony mass (Asterisk) arising from the
right side of the chest wall causing significant deformity. Multiple
other bony exostoses arising from Ribs and scapula (white arrow).
Postoperative 3D VR images of the chest in coronal (C) and oblique plane
(D) showing a significant reduction in the size of the bony mass.\selectlanguage{english}
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