8.3.1 Radiographic Imaging

Preoperative evaluation should involve comprehensive characterization of all aspects of the spinal deformity. Knowledge of the location of bifid or open bony segments and subcutaneously located dural elements is critical to avoid dural tearing or further neurologic injury, as posterior deficiencies cephalad to the frankly obvious level of the myelomeningocele can also exist. Pelvic and sacral anatomy must also be rigorously defined, as the majority of patients will require stabilization and fusion to the pelvis. Plain imaging should include posteroanterior and lateral sitting spine and anteroposterior pelvic radiographs. Flexibility evaluation can include supine bending, fulcrum bending, and/or spinal traction films to assess the need for anterior spinal release, spinal osteotomies, and/or vertebral column resection (VCR). Computed tomography (CT) scan and the use of three-dimensional (3D) CT technology can facilitate preoperative planning of surgical approach, correction techniques, and spinal and pelvic anchor placements, especially in cases involving multiple congenital malformations where plain radiography alone may not be sufficient. Magnetic resonance imaging (MRI) should be considered in cases of rapidly progressing curvature as spinal cord tethering, undiagnosed Arnold–Chiari malformation, syrinx, or progressive hydrocephaly from ventriculoperitoneal (VP) shunt malfunction may be present. ^{2 ,​ 3}

If the patient has a preexisting VP shunt, a preoperative shunt evaluation should include radiographic confirmation of the structural integrity of any shunts from point of exit from the skull, with particular attention to the cervical region where shunt fracture is most common. Preoperative brain CT or MRI can be invaluable as a comparison tool for assessing postoperative hydrocephalus should shunt failure after deformity correction occur. This is of particular importance if a structural failure (separation) of a shunt is noted preoperatively, as arrested hydrocephalus should not be assumed. ^{4 ,​ 5} Postoperatively, radiographic confirmation of shunt integrity along its entire length should be immediately obtained. Symptoms of hydrocephalus due to shunt failure can include headache, nausea, emesis, lethargy, extraocular movement abnormalities, cognitive changes, neurologic deterioration, and even respiratory arrest and death.

8.3.2 Medical Management

A multidisciplinary approach, including consultation with neurosurgery (for shunt management and consideration for detethering), plastic surgery (for assistance with incisional planning, skin closure, and wound management), urologic surgery (for placement of preoperative urinary catheters if bladder reconstruction or diversion procedures have been performed), and rehabilitative medicine colleagues (for optimizing postoperative rehabilitation and functional outcome) can solidify decisions regarding timing of surgery and plans for postoperative recovery.

Signs of impaired pulmonary function due to thoracic insufficiency syndrome (TIS) from increasing loss of thoracic volume due to scoliosis, thoracic lordosis, and/or diaphragmatic intrusion of the abdominal contents into the thorax should be recognized. On physical examination, this may present as labored breathing, including the presence of the “Marionette sign of Campbell.” ⁶ Pulmonary function testing may be useful to quantify the degree of pulmonary insufficiency. Radiographic measures of the space available for lung (SAL) may not adequately characterize the degree of thoracic insufficiency in spina bifida, as a constricted hemithorax may not be present. ⁷ A more useful measurement may be the Diaphragm Intrusion Index (DII), which quantifies the SAL after upward displacement of the diaphragm by the abdominal cavity is accounted for (Fig. 8‑2). ⁸ The DII can be calculated for each side of the thorax and so is independent of the presence of scoliosis and a constricted hemithorax.

Preoperative nutritional parameters including serum albumin and white blood cell count, urinalysis, and urinary cultures should be obtained, and treatment of urinary tract infection should be completed prior to surgery. ⁹ The choice of intraoperative and postoperative antibiotics should be based on sensitivities of preoperatively cultured urinary organisms. ¹⁰ Intraoperatively, verification of the patency of a Foley catheter placed into the urethra or a urinary diversion site is critical throughout the procedure to avoid catheter occlusion. This is particularly critical at bladder augmentation sites where mucous plugging of the catheter is problematic. Catheter occlusion during prolonged surgery can lead to kidney damage as well as overwhelming urosepsis, which can lead to patient demise postoperatively. A urinary protocol (see text box below) should be in place and strictly adhered to. ⁸

Meticulous inspection of the entire skin envelope is critical, including the skin overlying the feet and pelvic prominences. This also includes anterior stoma and any other anterior abdominal incisions. The posterior scar from previous neurosurgical closure over the neural placode should be carefully evaluated for capillary refill, hypertrophic scar, overall mobility, and adhesions to underlying bony structures (typically the posterior superior iliac spines [PSIS]; Fig. 8‑3). Areas of deep pitting may be present and difficult to sterilize. Scar configuration (midline, off-centered, cruciate, inverted “Y,” etc.) will greatly impact incisional planning. Trunk obesity, dentition, and overall hygiene should also be assessed.

Functional assessments should include detailed evaluation of motor and sensory level, upper and lower extremity use, ambulatory function and adaptive equipment where applicable, technique of independent or caregiver self-catheterization, and overall level of desired postoperative independence. Careful preoperative assessment of reliance on upper extremity and shoulder girdle function for mobility is important in counseling the patient or family regarding the potential effects of the use of muscle transfer flaps (if needed) on crutch, walker, or wheelchair propulsion. Range of motion of all major upper and lower extremity joints should be recorded. In ambulatory patients, hip contractures and lower limb alignment may affect ambulation postoperatively and may require treatment prior to or after any spinal surgery. Hip extension contractures can place undue tension on the spinal implants when the child is in a sitting position and lead to loss of fixation.

The social environment to which the child will be returning after surgery can also greatly impact the overall success of the procedure, and evaluation of family structure and dynamics by a Social Work team is essential.