CHAPTER 16 VERTEBRAL COLUMN AND LOWER EXTREMITY
KEY POINTS
The surgeon should understand the particular risks associated with each lesion and ensure that patients undergo a multidisciplinary evaluation preoperatively.
A contrast-enhanced MRI should be used to assess the skin-to-bone involvement of the patient’s anomaly.
The surgeon should monitor leg length and foot length inequality and angular lower extremity deformity and use epiphysiodesis/hemiepiphysiodesis before puberty if indicated.
Intraarticular involvement should be treated aggressively before joint destruction and contracture with sclerotherapy and arthroscopy.
Vascular anomalies that involve the vertebral column and lower extremity may require management by an orthopedic surgeon. Most lesions are isolated vascular malformations (for example, capillary, lymphatic, venous, or arteriovenous) or overgrowth syndromes (for example, congenital lipomatous overgrowth, vascular malformations, epidermal nevis, spinal/skeletal anomalies/scoliosis [CLOVES] syndrome, Klippel-Trenaunay syndrome, or Parkes Weber syndrome). Lesions involving the vertebral column can cause osteolysis and collapse of the vertebra, as well as scoliosis. Vascular anomalies of the lower extremity can result in vertical or circumferential overgrowth, leg-length discrepancy, hemarthrosis, contractures, pain, decreased ambulation, and/or an inability to fit clothing (see Video 16-1, Intraarticular Venous Malformation).
The key to a treatment plan is a thorough history and physical examination. In the history the surgeon must assess overall function and prior treatments. The patient should be asked if he or she can walk community or household distances. The surgeon should inquire if pain is problematic and interfering only with sports or with school, sleep, and mood. The surgeon should also ask about bowel and bladder dysfunction, back pain, and headaches, which can be signs of tethering or spinal cord involvement. Any patient with these symptoms must have an MRI of the neural axis before a surgical plan is made. The surgeon should ask about bleeding and lymphatic drainage from areas of malformation and inquire about any prior episodes of blood clots or bleeding and a family history of these conditions. Finally, the surgeon must inquire if infections have occurred and record the severity and frequency.
During the physical examination, a full-body examination is important. Gait should be assessed in ambulatory patients in the hallway (walking and running if possible). The surgeon should correct leg-length discrepancy by placing blocks under the shorter leg before an Adams forward bend test of the spine is performed with a scoliometer or free app to examine spinal asymmetry. The surgeon should determine whether a soft tissue mass is creating imbalance or whether it is truly a bony deformity. This can be difficult to determine on examination and usually requires imaging. Standing pelvic balance and shoulder symmetry should be assessed. The coronal and sagittal alignment of the spine and lower extremities should be noted. The surgeon should measure side-to-side thigh, calf, and foot circumference difference and leg-length discrepancy. Foot size difference and macrodactyly, syndactyly, and sandal gap should be noted. All joints should be assessed for range-of-motion and angular deformities, which are common. The surgeon should perform a full neurovascular examination.
Standing PA and lateral spinal films with any leg-length discrepancy corrected with blocks are a good start at assessing spinal deformity. Patients with significant scoliosis, back pain, and/or neurologic symptoms need a full spine MRI. For those with high-flow malformations (for example, arteriovenous malformations), angiography may be needed. Leg-length discrepancy can be assessed with a standing AP hips-to-ankles radiograph; newer low-dose systems such as EOS make these films accurate and provide less radiation exposure. Because foot height and bulk often contribute greatly to a significant leg-length discrepancy (anything greater than 2 cm/approaching 1 inch) in vascular anomalies, standing films are preferred to lying down scanogram measurement radiographs with a ruler, which do not include the foot.
For patients with soft tissue overgrowth, joint contractures, or pain, a contrast-enhanced MRI of the affected part is critical for surgical planning. This can reveal the presence of anomalous vessels, intraarticular involvement, and the extent of deep disease in the musculature and around nerves.
SURGICAL INDICATIONS
VERTEBRAL COLUMN/SPINE
Scoliosis in the general pediatric population is generally observed until the curve reaches 25 degrees and braced until 40 to 50 degrees. This is the point at which curvature bracing is ineffective and curve progression continues after skeletal maturity, which is why this is the threshold for spinal straightening and instrumented fusion. However, vascular malformations do not follow these rules. Most curves result from intrathecal involvement (commonly seen in CLOVES syndrome) or vertebral column structural instability and collapse (for example, lymphatic malformations and Gorham-Stout disease). Thus curve progression is common. Spinal fusion stabilization is considered for progressive curvature of more than 40 degrees. Neurosurgical intervention for spinal cord detethering, decompression, and resection of intrathecal masses is much more common in the vascular malformation population than in the idiopathic scoliosis population. Spinal stabilization is also considered for instability and fractures.
LEG-LENGTH AND FOOT-LENGTH DIFFERENCE
A leg-length difference of greater than 2 cm causes gait disturbance, pelvic imbalance, and secondary scoliosis and can be a later source of leg and back pain. Although shoe lifts are effective, this amount of difference requires a build-on platform to each walking shoe. This is difficult and tedious to maintain for a lifetime, particularly if the platform is several inches, which leads to ankle sprains and difficulty with uneven surfaces. During childhood, annual clinical examinations and shoe lifts are recommended. As patients approach puberty, their final predicted leg length and foot length can be estimated accurately by widely available tools such as the Green-Anderson or the Paley Multiplier method. Apps are now available that can also assist. Because major leg lengthening on the unaffected limb or femoral shortening on the overgrown side is much riskier and morbid in this group, guided growth or epiphysiodesis is the most widely recommended technique that has good success if used in time on the overgrown part.
ANGULAR DEFORMITY
Angular deformity such as genu valgum/knock knees or genu varum/bow legs can occur. Whenever possible, guided growth/hemiepiphysiodesis with implantable devices to tether one side of the physis should be used to avoid the morbidity of osteotomy.
INTRAARTICULAR INVOLVEMENT
When vascular malformations occur around joints, they can invade the capsule and cause recurrent hemarthrosis and eventual end-stage arthritis and contracture. If diagnosed early, aggressive sclerotherapy and synovectomy can stop this cycle. Whenever possible, arthroscopic evaluation and synovectomy with cauterization of intraarticular malformation should be used. Very few patients with vascular malformations are joint replacement candidates because of the nature of the soft tissue envelope. Therefore a severely arthritic contracted knee often warrants an amputation.
JOINT CONTRACTURE
In young life early contractures can be managed with physical therapy. Often the contracture is driven by deep muscle and joint disease, which should be treated aggressively when possible with interventional radiology injection and cryotherapies and arthroscopic ablation. Botox and serial casting are not indicated, because the muscles are not spastic. In select cases tendon lengthening is helpful. If there is focal muscle involvement with pain and contracture, muscle resection can be beneficial.
SOFT TISSUE OVERGROWTH
By 2 years of age, children with overgrowth malformation syndromes (for example, CLOVES syndrome or Klippel-Trenaunay syndrome) should see a multidisciplinary team trained in vascular anomalies. Assessment for anomalous veins should be done with closure in interventional radiology. The family should be educated about compressive wrapping of lymphedema in limbs and later compression garments where appropriate. For severe cases, oral sirolimus and other drug therapies should be maximized according to the recommendations of the team’s hematology and oncology members. Children with CLOVES syndrome should be put on a renal ultrasound Wilms tumor screening protocol. For patients with massive overgrowth that limits ambulation, fitting of clothing, and use of limbs, debulking is recommended. A staged approach is used, with the most affected part worked on first and in limbs from distal to proximal. For massively overgrown, nonfunctional limbs or for those creating a parasitic limb or cardiac failure, amputation is recommended.
SURGICAL MANAGEMENT
VERTEBRAL COLUMN/SPINE FUSION
The surgeon should assess the type of malformation and perform three-dimensional imaging and planning. The use of titanium implants will allow a postoperative MRI. Many patients have significant anomalous venous systems, and thus all patients should be evaluated by hematology and interventional radiology before surgery. Many patients need preoperative embolization with inferior vena cava (IVC) filter placement. Bleeding should be expected and mitigated with preoperative embolization, normalization of D-dimer and fibrinogen (often with preoperative anticoagulation with enoxaparin sodium [Lovenox]), and intraoperative use of special cautery devices. Often a combined team approach with neurosurgery, orthopedics, and plastic surgery is helpful.
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