DISCUSSION
We herein, reported a 17-year-old boy with atypical Scheuermann’s kyphosis who underwent Smith-Peterson Osteotomy and posterior fixation surgery, and unlike most cases, had a remarkable improvement in his signs and symptoms with no significant complications. Usually, the management of Scheuermann’s kyphosis is based on conservative treatment of the patient’s symptoms, and surgical interventions are reserved for severe cases [11]. The current concept regarding the management of the patients with Scheuermann’s kyphosis is based on the TK degree. Patients with less than 60° TK are managed conservatively with analgesics, physical therapy, and sport medicine. In patients with TK of 60-75°, hyperextension brace in administered with the aim of decreasing 15° of the TK. In those, with TK of more than 75°, surgery is indicated [11]. Surgery is also indicated in those with intractable pain, neurological impairment, and progressive curve [4, 12].
In the surgical approach to typical Scheuermann’s kyphosis, two methods are well established; the first one is the combination of anterior release and posterior fusion, and the second one is the posterior-only approach. Since anterior release and posterior fusion in Scheuermann’s kyphosis composes of two consecutive interventions, it is accompanied by more complications, duration of operation, and blood loss. It is also accompanied by higher rates of neurologic, cardiologic, and pulmonary complications [12, 13]. The aim of the surgery is not only the correction of the kyphosis, but also correction of the all-sagittal balance parameters [13]. In order to improve the pain and the neurological symptoms, the cervical, thoracic and lumbar parameters should be corrected during the surgery [8, 10]. The stable vertebra should be detected preoperatively in order to design a perfect construct for correction of the spine parameters [13, 14]. The most common long-term complications of the surgery remains the distal junctional disease compared to the proximal disease [15, 16]. In this case report, we performed a posterior-only approach for correction of the kyphosis in this young boy. The posterior-only approach along with Smith-Peterson osteotomy, successfully improved the TK and all the sagittal balance parameters. We experienced no intraoperative and postoperative complication and the patient’s sign and symptoms relieved successfully. Thus, we recommend evaluation of the sagittal spine parameters preoperatively in order to perform a successful posterior-only approach for correction of the TK and improving the patient’s sign and symptoms.
There are various differences between the typical and atypical Scheuermann’s kyphosis. The typical Scheuermann’s kyphosis is mid-thoracic and encompass the radiological signs of the disease such as Schmorl’s nodule, vertebral wedging and disc narrowing more frequently [5]. The atypical Scheuermann’s kyphosis is usually thoracolumbar and is more frequently symptomatic compared to the typical disease [1, 6, 11]. In addition, patient with atypical symptoms have less frequently the radiological characteristics of the disease [4, 7]. The adult Scheuermann’s kyphosis is also accompanied by a 25% rate of scoliosis that makes the entity more complex [1, 11].
Weiss et al. showed that a holistic approach to the rehabilitative programs directed toward patients with thoracic and thoracolumbar Scheuermann’s kyphosis can significantly decrease the pain in the patients [17]. Previously, combined posterior and anterior approaches were the gold standard of treatment in surgical interventions, but recently, posterior-only approaches are brough into attention due to fewer postoperative complications and better outcomes [7]. Dai et al. reported a series of atypical lumbar Scheuermann’s kyphosis associated with scoliosis in a family and concluded that this condition might have genetic predisposing factors. The patient underwent surgical fixation and in the three-month follow-up of the patient, no major complication was found [18].
Wang et al. also reported a case of atypical Scheuermann’s kyphosis in a patient with heterozygous mutation in COL1A2 gene. Consequently, the patient was diagnosed with osteogenesis imperfecta. An association might exist between atypical Scheuermann’s kyphosis and osteogenesis imperfecta, but since patients with atypical lumbar Scheuermann’s kyphosis do not regularly undergo genetic sequencing, such associations are unclear [19]. The patient in that study did not undergo operation and the comparison of results is not possible. Nasto and colleagues performed a study on 64 patients with Scheuermann’s kyphosis and 33 controls. The patients underwent surgery and were followed-up for six months. They evaluated and compared the post-op cervical sagittal alignment in patients with thoracic and thoracolumbar Scheuermann’s kyphosis. They found that the cervical lordosis increased in patients with thoracolumbar Scheuermann’s kyphosis, whereas the patients with thoracic Scheuermann’s kyphosis had a decrease in their cervical lordosis [20].
Van Loon and colleagues performed pedicle subtraction osteotomy on eleven patients with atypical Scheuermann’s kyphosis and the patients were followed-up for about 3.5 years. They showed that this procedure was significantly effective in decreasing the pain of the participants. They concluded that this intervention could be used as an add-on option to previously established treatments of atypical thoracolumbar Scheuermann’s kyphosis [21]. Tsirikos reported two cases with atypical thoracolumbar Scheuermann’s kyphosis who had spontaneous fusion and ankylosis in the kyphotic vertebrae. The author concluded that in patients with anteroposterior fusion of the discs, an anterior release of the vertebrae and a posterior fusion might be the intervention of choice [22].
In a case report by Lamartina, a 27-year-old man with severe kyphosis was operated on by a posterior approach for fusion of T3-L2 vertebrae. No data regarding the follow-up of the case is available, but this approach is speculated to have less post-operative neurologic complications since the spinal cord is less likely to be manipulated [14]. In our case, in a follow-up period of two years, no neurologic deficit was seen and no further surgical intervention was needed. In a study by Heegaard et al. performed on 22 cases, the authors reported that the complication rate in the surgical treatment of Scheuermann’s kyphosis was as high as 77% [16]; however, the authors did not evaluate the complications based on the surgical approach. In a much larger study by Coe et al. performed on The Scoliosis Research Society morbidity and mortality database of 683 patients, the authors found that the complication rate for surgical repair of Scheuermann’s kyphosis was 14%. Only 1.9% of the patients suffered from acute neurologic complications. They also compared the posterior-only approach to the patients with combined anterior and posterior approach and found that although the complication rate in posterior-only approach was lower than in combined anterior and posterior approach, this difference was not statistically significant [15].
Lonner and colleagues reported the surgical outcomes in 78 typical Scheuermann’s kyphosis patients and compared the posterior-only and combined anterior and posterior approaches. They found that patients undergoing posterior-only surgical interventions had better outcomes; however, in that study, the preoperative lordosis angle, kyphosis angle, and greatest Cob angle in the two groups differed significantly; consequently, no definite conclusion could be made based on this study’s results [23]. Etemadifar et al. compared the complications and outcomes of the two approaches in 30 patients with Scheuermann’s kyphosis. They concluded that the surgical outcomes of the two approaches do not differ significantly; however, the complications of posterior-only surgical approach were much lower than the combined anterior and posterior approach; consequently, posterior-only approach is usually the first recommended surgical intervention to treat this condition [12].
Some rare complications have also been shown to be associated with anterior release and posterior fusion surgery. For instance, Daniels et al. reported acute celiac artery compression syndrome as a complication of this intervention [24]. Moreover, Soares do Borito et al. encountered anterior sternoclavicular dislocation after this surgery [25]. In our case with atypical thoracolumbar Scheuermann’s kyphosis, anterior release and posterior fusion was performed and no complication, either acute or chronic, mild or severe, was encountered in the two-year follow-up period. We have summarized the summary of the previously reported cases in Table 2.