15 Spine Surgery in the Developing World
The United Nations has classified countries on the basis of their state of economic and social development as least developed, developing, transitional, and developed; 48 countries are considered least developed, 95 developing, 22 transitional, and 26 developed. 1 , 2 Musculoskeletal diseases continue to produce major disability around the world. 3 , 4 Approximately half of the world′s population has no access to orthopedic care, including pediatric spine deformity care, which is a highly specialized area of orthopedic care. The problem is made worse by the lack of qualified personnel, the inadequate facilities, and the inability of patients to access the few existing facilities. 5 The combination of these factors has led many patients to live with severe and neglected spine deformities. The relative distribution of causes of death differs markedly between developed and developing countries. Of special interest to orthopedic surgeons is the prominence of tuberculosis, the sequelae of motor vehicle accidents, and congenital anomalies as causes of death in developing nations. 4 – 6 Spine surgery has benefited from the extraordinary developments of spine assessment, imaging, and complex surgical techniques of instrumentation in recent decades. These benefits are lacking in the developing world because even basic radiographic studies for spine deformity assessment are often nonexistent. 5 , 7
Families of pediatric patients with spine deformities often lack the financial resources to seek medical care, and thus they turn to alternative and ineffective treatments. These patients present a unique challenge in developing nations such as Ghana, where there is not a single trained spine deformity surgeon for 26 million people. 8 Those who are fortunate enough to obtain surgical treatment after failed conservative methods present with a myriad of medical comorbidities and advanced deformities, and thus they pose significant challenges to the medical treatment team. A multidisciplinary approach is needed to manage these patients perioperatively for successful outcomes. Patients presenting to our institution in Ghana are managed with a variety of nonsurgical and surgical methods customized to suit patients’ deformities and the available long-term care. A significant number of pediatric patients with complex spine deformities with restrictive pulmonary disease have to be managed with long-term preoperative halo gravity traction, a nutritional optimization program, and complex surgical interventions and postoperative management for successful outcomes. 9 , 10
The best way to circumvent the obstacles associated with the management of pediatric spine deformities is for their early detection and treatment to be among the leading major health concerns in the minds, actions, and funding priorities of international health agencies, governments, nongovernmental organizations, funders, and the general public. 5 , 11 We have embraced this mission of the Bone and Joint Decade at the Foundation of Orthopaedics and Complex Spine (FOCOS) Orthopaedic Hospital in Ghana, and we hope to facilitate establishing an infrastructure for sustainable programs and services in the West Africa subregion. Due to the complexity of spine deformities and the lack of resources, a good way to establish a treatment center is to follow the guidelines developed by the Scoliosis Research Society.
Spine Deformity and Disorders in the Developing World
All manner of spine deformities and disorders are seen in the developing world. At our center in Ghana, the majority of patients present with scoliosis, which is the most common pediatric deformity. It is idiopathic in origin in 75 to 90% of cases ( Fig. 15.1 ). The remaining 10 to 25% may be secondary to congenital anomalies, neuromuscular disease, infection, tumor, injury, or as part of such syndromes as Marfan′s and neurofibromatosis. Of utmost importance is that many patients present with severe early-onset spine deformity and failure to thrive. Casting or bracing facilities are not available in many underserved regions for these patients, leaving surgery as the only treatment option available.
For adolescent patients who have gone untreated, the deformities most often exceed 100 degrees in one or two planes and are associated with severe restrictive lung disease. A forced vital capacity (FVC) below 40% is a common presentation. We have assessed the nutritional state of our pediatric population and have recognized that 90% of these patients were undernourished or small for their age. 12 Using height to determine the patient′s body mass index (BMI) is very misleading, so we have resorted to using the arm span as a proxy for height in calculating an appropriate and meaningful BMI. Moreover, one cannot always use the chronological age as a factor in deciding on the surgical treatment of patients with early-onset scoliosis, as is done in developed countries; instead, we use skeletal age, and have instituted growing rod treatment programs in some 12- and 13-year-olds who present with skeletal age 6 or 7. Growing rod or growth friendly treatment includes utilization of limited fusion of the spine, allowing the unfused spine to grow. Periodic lengthenings are done to keep up with longitudinal growth of the spine. Early identification of patients who are malnourished or at risk is essential to institute timely nutrition interventions. Our nutritional optimization program has achieved improvements in weight and BMI prior to surgical intervention in a significant number of patients ( Fig. 15.2 ).
Tuberculosis (TB) spondylitis leading to post-TB kyphosis is prevalent in the developing world and causes some of the most severe kyphotic deformities and paralysis. It is not uncommon to see very young patients presenting with severe kyphosis exceeding 100 degrees, with neurologic impairment. 9 , 13 Medical management is still the mainstay of nonoperative treatment and is available through public health programs in most developing countries. 14 Surgical intervention is reserved for those with radiographic at-risk signs as described by Rajasekaran and associates. 15 Patients with neurologic deficits, severe and painful deformities, or pulmonary compromise are considered candidates for surgical intervention.
Our pediatric patients range in age from 12 months to 21 years, and they hail from different countries in Africa. They usually are not accompanied by a parent at the time of presentation for surgical treatment. The parents and guardians of some of the patients have been met during outreach visitations to the countries of origin by members of the FOCOS team, who have had the opportunity to discuss treatment options with them and their referring physicians. This sometimes presents an ethical dilemma when it comes to obtaining informed consent for complex spine surgery. The senior author and referring physicians communicate all treatment plans and complications with the families or guardians for a comprehensive consent before the patients depart for treatment in Ghana. Out-of-state patients are accompanied by a caregiver who also serves as the interpreter and proxy guardian to provide additional treatment consents.
Upon presentation to the clinic, a comprehensive assessment is done, which includes a medical, physical, and spinal exam. An angle of trunk rotation (ATR) exceeding 30 degrees, which falls outside the limits of the scoliometer device, is very common. A thorough neurologic evaluation is performed and documented using the American Spinal Injury Association (ASIA) grading system. Older children are given the English version of the Scoliosis Research Society Outcomes Questionnaire (SRS-22), a health-related quality-of-life (HRQOL) instrument, to complete. 16 We have recently compared the preoperative SRS-22 results of patients from Ghana, patients from New York City, and controls who were matched for age and sex. Adolescents without scoliosis had significantly better scores than scoliotic adolescents. Ghanaian scoliotic adolescents had significantly worse HRQOL scores than American scoliotic adolescents. These differences should be kept in mind when treating the emotionally vulnerable adolescent population in developing nations.
Radiographic studies including standard standing or upright anteroposterior and lateral views on 36-inchlong films are obtained to evaluate curve magnitude, type, and etiology. Many developing countries lack sophisticated radiographic imaging facilities and have to rely on radiographs not depicting the entire spine on a single film. In such cases, practitioners must piece together segments of the radiographic images to assess curve magnitude and etiology. Several radiographs may be needed to evaluate specific segments of the spine, resulting in increased radiation exposure and cost.
Patients with curves exceeding 100 degrees in either plane with less than 20% flexibility are considered candidates for a halo gravity traction program. 10 Advanced imaging is very hard to come by in many developing countries, and one may have to rely on only a careful review of the plain radiographs and a detailed neurologic assessment to make treatment decisions. Access is also limited. Ghana, for example, currently has 10 magnetic resonance imaging (MRI) and 20 computed tomography (CT) scan machines for 26 million people. The cost may also be prohibitive for many patients. We strive to obtain an MRI on all neurologically impaired patients and those with congenital anomalies preoperatively. For the latter group of patients, an echocardiogram and renal ultrasound is also obtained, as these patients have been found to have a higher incidence of associated anomalies of these organ systems 17 At our center, a global fee scale has been developed for surgical patients who are able to afford the nominal charges, which includes all treatment modalities, professional fees, imaging, hospital stay, and laboratory studies.
Medical and Anesthetic Considerations
Even though a multidisciplinary approach is preferred to manage spine deformity patients, such specialists may not be available in under-served regions. Thus, the preoperative evaluation should determine the presence of associated medical conditions and should try to obtain the records of previous medical and surgical procedures. Common coexisting medical conditions encountered in the West Africa subregion include tuberculosis, sickle cell disease, viral hepatitis, and HIV. Patient with these conditions or high viral titers are counseled to postpone surgical intervention and consider medical management accordingly.
The etiology, location, and degree of the deformity should be noted, and any other congenital abnormalities should be investigated to plan the most appropriate procedure for the particular case. This will enable a meaningful estimation of the duration and complexity of surgery, and preparation for potential complications. Particular attention should be paid to the respiratory and cardiovascular systems as well as to the central nervous system (CNS). Patients with severe spine deformities may have wheezes on chest examination. The presence of dyspnea at rest or on minimal exertion, orthopnea, or paroxysmal nocturnal dyspnea is indicative of imminent cardiac failure and loss of cardiovascular reserve. These conditions are occasionally seen in very severe deformities exceeding 100 degrees in young patients. Included in our risk stratification protocol are the American Society of Anesthesiologists (ASA) measurement, the BMI, the etiology, the curve magnitude, the Fusion levels, the osteotomy type, and the neurologic status. An electrocardiogram (ECG), a pulmonary function test (PFT), and echo cardiography, if available, should be ordered preoperatively. Cervical mobility and upper airway anatomy are also assessed to determine any potential airway or positioning difficulties ( Table 15.1 ).
Preparation should be made for the possibility of blood transfusion, for prolonged stay in the intensive care unit (ICU), and for postoperative pain management. These modalities are discussed with the patient and guardian as part of the informed consent interview.
Respiratory Effects and Postoperative Considerations
The FVC is a reliable prognostic indicator of perioperative respiratory reserve. 18 Based on our knowledge that patients with severe curves or neuromuscular disease have poor pulmonary function and may have a stormy postoperative course, we routinely ventilate patients postoperatively for 12 to 24 hours. This has reduced reintubation events in the middle of the night when resources and staff are limited. We highly recommend such protocols when treating severe spine deformity patients in developing countries ( Fig. 15.2 ).
Congenital spine deformity may also be associated with congenital heart conditions such as mitral valve prolapse, coarctation, cyanotic heart disease, and congenital chest wall abnormalities leading to thoracic insufficiency syndrome. Pulmonary hypertension may result in right-heart failure and eventually death.
Important anesthetic considerations in surgery for spinal deformity include management of the patient in the prone position, hypothermia secondary to a long procedure with an extensive exposed area, replacement of blood and fluid losses that may be extensive, maintenance of spinal cord integrity, and blood conservation techniques. A general anesthetic technique with intubation and mechanical ventilation is used in pediatric spine deformity surgery in all regions of the world. 19 The aim is to maintain an adequate depth of anesthesia, which enables intraoperative neurophysiological monitoring, if available. Our protocol includes hemodynamic monitoring, preoxygenation, intravenous induction with midazolam 0.1 mg/kg, fentanyl 5 µg/kg, and propofol 150 to 300 mg. This enables tracheal intubation without the use of a muscle relaxant. Bite blocks are inserted to prevent the tongue bites during stimulation of motor evoked potentials (MEPs). Maintenance of anesthesia is done with propofol, fentanyl, and oxygen.
Routine hemodynamic monitoring intraoperatively includes invasive blood pressure (BP) assessment via a radial artery cannula. BP measurement starts at induction in patients with cardiac instability. A central line is not always available, and therefore it is not routinely used intraoperatively. We have performed hundreds of complex spine procedures in pediatric patients without the central line, with very favorable outcomes. The central line is only placed when there is significant morbidity or difficult peripheral intravenous access. A urethral catheter is inserted routinely to monitor urine output and hence tissue perfusion.
The prone patient positioning requires good, coordinated teamwork as accidental extubation or dislodgment of intravascular and urinary catheters can occur. Blindness, though rare, has been reported after spine surgery, and has been attributed to multiple causes such as anemia, hypotension, and improper positioning. 20 The padding of the eyes is therefore frequently checked during surgery. Vulnerable areas such as peripheral nerves and genitalia should be protected from compression and soft tissue damage. The arms are anteriorly flexed and abducted to reduce tension on the brachial plexus. Invasive BP monitoring is started at this point, and noninvasive BP monitoring is set at 30-minute intervals for intermittent comparison.
Surgical Planning, Preparation, and Intervention
Surgical treatment of pediatric patients in developing countries is fraught with potential problems. The deformities are severe and neglected. The patients present with a myriad of comorbidities that were addressed above. When a patient is finally considered to be a candidate for surgical intervention, we determine the surgical risk score based on several risk factors. We have recently published a new method for surgical risk stratification. 12 The risk level is classified from 1 (low risk) to 5 (high risk). In our system at FOCOS, we determine the risk level based on the scores on our stratification questionnaire, as follow: level 1, 1 to 20 points; level 2, 21 to 40 points; level 3, 41 to 60 points; level 4, 61 to 80 points); and level 5, 81 to 100 points. Multiple regression analysis indicated a significant correlation between FOCOS level and estimated blood loss, length of surgery, and neurologic and overall complication ratio ( Table 15.2 ). This assessment has allowed us to carefully select and prepare pediatric patients for complex spine surgical intervention. Severe and stiff deformities with restrictive pulmonary disease are considered for long-term halo gravity traction (HGT). Our halo gravity protocol includes starting at 20% body weight and increasing it by 10% per week until 50% body weight is achieved. In our review of patients treated with this method, scoliosis improved from an average of 131 degrees to 91 degrees (31%). Pure kyphotics improved an average of 22%. Deformity correction with HGT plateaued at 63 days. There were no neurologic complications. We were able to demonstrate that long-term HGT is safe and provides curve correction as well as improves the pulmonary function, and in most cases has obviated the need for complex and high-risk three-column osteotomies, especially when resources are limited. For patients with early-onset spine deformities with severe kyphoscoliosis, the HGT has been shown to significantly improve the curves to render them amenable to growth-friendly instrumentation ( Figs. 15.2 and 15.3 ).
The spinal cord is at risk of injury during corrective spine surgery and when the spinal canal is surgically invaded, such as in three-column osteotomy procedures. The incidence of motor deficit or paraplegia after surgery to correct scoliosis in the absence of spinal cord monitoring techniques has been quoted as between 3.7% and 6.9%. 10 , 14 , 21 This has been reduced by intraoperative monitoring (IOM) to 0.5%. In the developed world, spinal cord monitoring is a standard practice and plays a major role in the management of complex pediatric deformities. 9 , 13 , 21 This modality is not available in many treatment centers in the developing world, so the surgical team has to resort to the wake-up test. This may take some time because advanced anesthetic methods for total intravenous anesthesia (TIVA) with medications like remifentanil may not be available. Patience is therefore required during the reversal process of waking up the patient. When dealing with patients who speak a language different from the that of the surgical team, a preoperative rehearsal of the wake-up test with an interpreter is crucial.