Pectus - Preoperative Assessment - Genetics

In pectus excavatum clinic, skeletal evaluation for Marfan syndrome includes examination for wrist sign (thumb and pinky finger overlap when wrapped around wrist) and thumb protrusion past the ulnar border to evaluate for long bone overgrowth relative to trunk.

Arm span to height ratios and upper to lower segment ratios are evaluated as part of Marfan syndrome skeletal assessment.

Skeletal findings evaluated for Marfan syndrome include pectus excavatum, pectus carinatum, scoliosis, and hind foot deformities.

The cardiac risk associated with Marfan syndrome includes aortic dissection and mitral valve prolapse, as well as retinal detachments.

Diagnosis of Marfan syndrome is largely centered on cardiac findings, with echocardiogram or MRI as main tools to evaluate for dilated aortic root.

Lens dislocations are evaluated as part of Marfan syndrome assessment, and fibrillin gene testing is performed in cases with suggestive findings.

In patients with Marfan-like characteristics, evaluation may be extended to other genetic syndromes involving TGF beta signaling, which is implicated in aortic remodeling and long bone overgrowth.

Ehlers-Danlos syndrome is by far the more common condition evaluated in pectus patients compared to Marfan syndrome.

Ehlers-Danlos syndrome represents a grouping of related conditions affecting connective tissue, not a single condition.

Classic type Ehlers-Danlos is due to defects in collagen 5 and is characterized by joint hypermobility and abnormal skin that is fragile, thin, with weak and papery thin scars.

Vascular type Ehlers-Danlos is caused by mutations in collagen 3 and is characterized by internal organ fragility rather than hypermobile joints.

Vascular Ehlers-Danlos is one of the least common conditions seen in pectus clinic.

For vascular Ehlers-Danlos, screening looks for family history or personal history of ruptures (bowel, aortic, or uterine rupture).

Genetic testing for vascular Ehlers-Danlos is 99% sensitive.

The hypermobile type of Ehlers-Danlos is what is typically evaluated in pectus clinic, characterized by very flexible patients.

The Beighton score is a test of 9 different joints, scored 1 for each side except the hips, used to formally assess hypermobility.

Beighton score criteria include: hyperextension of arms past 10 degrees, hyperextension of pinky past 90 degrees, apposition of thumb to forearm, hyperextension of knee past 10 degrees (all scored bilaterally for 8 points), and placing hands flat on floor without bending knees (assessing hip hypermobility).

Five or more hypermobile joints on the Beighton score meets criteria for generalized hypermobility.

Additional findings evaluated for hypermobile Ehlers-Danlos include mild skin changes (mild hyperextensibility, easy bruising, scarring abnormalities, striae) and family history of hypermobility.

The dividing line between being flexible and having Ehlers-Danlos may be very fuzzy; diagnosis looks for similar findings in family members and presence of clinical problems.

Clinical problems associated with hypermobile Ehlers-Danlos include: loose joints that dislocate, chronic pain, chronic headaches and migraines, temporomandibular joint dysfunction, easy bruising and bleeding, orthostatic hypotension or dizziness with standing, episodes of racing heartbeat, chronic constipation with irritable bowel syndrome, panic and anxiety disorders, and sleeping problems.

Most adult patients with hypermobile Ehlers-Danlos have almost all of the associated problems (pain, headaches, TMJ, bleeding, orthostatic issues, IBS, anxiety, sleep problems).

In children with hypermobile Ehlers-Danlos, problems may be very mild or not evident, but may begin to emerge during puberty, which may coincide with when they consider pectus surgery.

The chronic pain aspect of hypermobile Ehlers-Danlos can affect whether patients are at risk for more pain from pectus surgery.

Hypermobility is a risk factor for fibromyalgia; 50% of teenagers diagnosed with fibromyalgia have hypermobility.

Fibromyalgia involves central sensitivity to pain, meaning patients are unable to filter out unwanted pain signals in the same way as other persons.

A hypermobile patient may be at risk for having more problems with chronic pain due to central pain sensitivity mechanisms.

One clinician's screening approach for pectus patients includes checking for double-jointedness, appearance of Marfan disease, arachnodactyly, and striae, with referral to genetics if findings are present.