Disclosure In 1920, Scheuermann first described the clinical findings of structural thoracic kyphosis. However, it was not until 1964, that Sorensen defined the radiographic findings in Scheuermann kyphosis. He described the defining characteristic of anterior wedging of 5° or more in at least 3 adjacent vertebral bodies. This helped to objectify and differentiate Scheuermann kyphosis from postural round back deformity. Scheuermann thoracic kyphosis is a structural deformity of the thoracic spine (see Image 1), defined by anterior wedging of at least 5° of 3 or more adjacent thoracic vertebral bodies. Further radiographic findings include Schmorl nodes and endplate narrowing. While the etiology of Scheuermann kyphosis remains unknown, the natural history and treatment indications are well described. Both adolescents and adults can develop symptoms associated with Scheuermann kyphosis. Adolescents typically develop a progressive cosmetic deformity, which first brings them in for medical attention, whereas adults with long-standing deformity typically develop pain as an indication for treatment. Bracing has been demonstrated to be an effective treatment modality for the adolescent with a progressive deformity, while pain often responds to nonoperative care, including physical therapy and anti-inflammatories in both adolescents and adults. In patients with a progressive deformity, refractory pain, or neurologic deficit, surgical correction may be indicated. Guidelines for treatment, surgical options and techniques, and complications are discussed in this article. History of the Procedure: Historically, the surgical care of Scheuermann kyphosis shadows the surgical care of idiopathic scoliosis. The role of surgical care for adolescent kyphosis was debated in the sparse literature prior to 1960. In 1962, Paul Harrington introduced the Harrington rod to augment the surgical correction of scoliosis. In 1965, Moe presented his nonoperative and operative results from a posterior approach in the treatment of adolescent kyphosis. Postoperative curve progression and a high pseudoarthrosis rate complicated the posterior-only approach. Combined anterior and posterior surgical approaches for Scheuermann kyphosis were first popularized in the 1970s. These techniques increased fusion rates and correction and remain the foundation of current surgical approaches. More recent innovations include simultaneous thoracoscopic anterior release with postinstrumented fusion. Problem: Differentiating normal thoracic kyphosis from abnormal thoracic kyphosis is somewhat problematic. Normal thoracic kyphosis is actually dynamic throughout life and typically increases. Fon et al measured thoracic kyphosis in children younger than 10 years and in adolescents aged 19 years and younger. In those younger than 10 years, he found that the average kyphosis was 20.00° with a standard deviation (SD) of 7.85 for boys and 23.87° with an SD of 6.67 for girls. In adolescents, the kyphosis had increased to an average of 25.11° with an SD of 8.16 in boys and 26.00° with an SD of 7.43 in girls. Females, on average, have slightly greater kyphosis in the thoracic spine throughout life. This difference between males and females increases further when they are older than 40 years. In women aged 50-59 years, the average kyphosis measured 40.71° with an SD of 9.88°, while men in the same age group had an average thoracic kyphosis of 33.00° with an SD of 6.46. For purposes of definition, any degree of kyphosis of more than 40° should be deemed abnormal. Additionally, any degree of kyphosis at the thoracolumbar junction or in the lumbar area of the spine should be considered abnormal. Frequency: The prevalence of Scheuermann kyphosis is estimated to affect 4-8% of the general population. In his 1964 description of Scheuermann kyphosis, Sorensen reported a prevalence of 0.4-8.3%. In 1991, Scoles et al reported on their review of 1384 cadaveric specimens. They demonstrated a 7.4% prevalence of Scheuermann kyphosis. While the prevalence of Scheuermann kyphosis is generally accepted to be essentially equal in males and females, this finding is debated in literature as well. Bradford et al reported a female-to-male ratio of Scheuermann kyphosis of 2:1. Meanwhile, Murray et al reported the exact opposite finding with a 2.1:1 male-to-female ratio. In Sorenson's previously cited work, 58% of the patients were male, while 42% were female. Etiology: The proximate cause of Scheuermann kyphosis has not yet been determined. Scheuermann initially hypothesized that avascular necrosis of the ring apophysis led to premature cessation of growth anteriorly and subsequent wedging of the vertebral body. Schmorl later postulated that traumatic herniations of disk material through the vertebral endplates led to subsequent loss of disk height and anterior vertebral wedging. Both of these theories were disproved later. In 1978, Halal reported on 5 families in which Scheuermann appeared to transfer in an autosomal-dominant mode of inheritance. To date, the genetic marker has not been determined. Skogland and Ascani proposed other theories that Scheuermann kyphosis is based in a genetic inheritance. Skogland reported on 62 females aged 9-18 years, whose mean height was an average of 2.5 SDs above average. Of these 62 females, 18 had thoracic kyphosis of more than 40°, with 11 additional participants having vertebral anomalies consistent with Scheuermann disease. Ascani also presented work demonstrating a similar correlation between Scheuermann kyphosis and height. He also demonstrated increased levels of growth hormone. Mechanical factors have been postulated as a cause for Scheuermann kyphosis. Scheuermann initially noted a higher incidence of kyphosis in industrial workers and found that hyperextension bracing is helpful in curbing the progression of Scheuermann kyphosis, which would support a mechanical etiology. However, the radiographic and histologic changes of Scheuermann kyphosis have not yet been demonstrated to be in fact secondary or primary in the development of Scheuermann kyphosis. Pathophysiology: While the etiology of Scheuermann kyphosis is not yet understood, the histologic and pathologic findings are well described. Radiographically, 3 adjacent wedged vertebral bodies of at least 5° each is pathognomonic for Scheuermann kyphosis. Anatomic findings include a thickened anterior longitudinal ligament (ALL) with narrowed intervertebral disks. The vertebral bodies are wedged, and traumatic disk herniations through the endplates are consistent findings. The ratio of collagen to proteoglycans in the matrix of the endplate in patients with Scheuermann kyphosis has been described as low compared to that in patients without the condition. This relative decrease in collagen has been hypothesized to lead to an alteration in the ossification of the endplate and, thus, to altered vertebral body growth. Finally, osteoporosis has been postulated to have a role in the pathology and etiology of Scheuermann kyphosis. In 1976, Bradford reported on 12 patients with Scheuermann kyphosis who were prospectively studied with an extensive osteoporosis workup, including an iliac crest biopsy. Some of the patients with Scheuermann kyphosis were demonstrated to have a mild form of osteoporosis, although the cause and effect of this finding in terms of developing Scheuermann kyphosis was not made. A follow-up study in 1989 by Gilsanz reported 20 adolescent patients, aged 12-18 years, with Scheuermann kyphosis, who demonstrated no evidence of osteoporosis as measured by quantitative computed tomography (CT). Bradford, however, had surmised that the osteoporosis was transient and somehow led to altered vertebral growth and, thus, the formation of Scheuermann kyphosis. This etiologic hypothesis remains debated. Clinical: Scheuermann kyphosis may be entirely asymptomatic. However, patients with Scheuermann kyphosis who present for medical attention generally have problems that fall under one of the following 5 categories:
When present, pain should be highly concordant with the location of the spinal deformity in Scheuermann kyphosis. Pain may be present in either adolescence or adulthood, although it is a more typical presenting complaint in adults. Characteristically, the pain is located just distal to the apex of the deformity and then radiates laterally in a paraspinal pattern. The pain also is activity related and often abates with rest. Address atypical pain, particularly in adolescents, with further diagnostic studies. Adults with pain often have low back pain, secondary to hyperlordosis below the Scheuermann kyphosis and subsequent degenerative disk disease and facet arthropathy, or the pain may be due to associated spondylolisthesis. Note that pain is the presenting complaint in 20-60% of patients with Scheuermann kyphosis. Progressive deformity in the absence of radiographic conformation is difficult to document, although the history of the deformity should be queried. Patients and, particularly, family members often note a deformity worsening over time. Clothes fit differently, shoulders appear more rounded, and it may appear that the length of the arms is increasing out of proportion to the rest of the body. Radiographic confirmation of progressive deformities is ideal. If progression of the curve is documented, particularly in an adolescent, consider more aggressive treatment options. Neurologic risk related to Scheuermann kyphosis is quite rare, but, when present, it typically mandates a surgical approach. A short-segment severe deformity generally is considered to be a curve that is at highest risk secondary to the cord being draped over the deformity with anterior compression. Lonstein et al demonstrated an average kyphosis of 95° in patients that presented with neurologic compromise. However, Ryan and Taylor presented 3 patients with Scheuermann kyphosis and neurologic compromise with an average kyphosis of only 54°. Spinal stenosis of the lumbar spine below the deformity may lead to neurogenic claudication in the adult patient, and, while not directly attributable to Scheuermann kyphosis, it may complicate the clinical picture. Congenital thoracic stenosis has been reported in association with Scheuermann kyphosis and may lead to myelopathy or intraoperative complications during correction of the deformity. Cardiopulmonary compromise as a presenting complaint for patients with Scheuermann kyphosis is quite rare. Restrictive lung disease has been documented by Murray et al, yet this was in curves of more than 100°, with the apex of the curve located in the upper thoracic region. Sorensen reported earlier that chest wall abnormalities in patients with Scheuermann kyphosis had no negative affect on cardiopulmonary function. Finally, cosmetic issues should not be underestimated in the evaluation of a patient with Scheuermann kyphosis. Address these concerns specifically and aggressively with the individual patient, as these concerns ultimately may be the driving force behind the patient's decision process. When cosmesis is the isolated indication for treatment, particularly for surgical care, exercise caution. After the history has been well documented, a physical examination completes the initial clinical evaluation. Scheuermann kyphosis must be differentiated from postural kyphosis. On physical examination, this difference is made on hyperextension. Patients with Scheuermann kyphosis, even adolescents, demonstrate a structural deformity that only partially corrects on hyperextension. Patients with postural kyphosis, by contrast, have flexible deformities. Forward flexion delineates the deformity quite well, with shorter angulated curves presenting as an A-frame deformity. Overall, sagittal alignment usually is maintained, secondary to compensatory hyperlordosis of both the cervical and lumbar spine. Perform a lower extremity neurologic evaluation, paying particular attention to any signs of upper motor neuron compromise. Findings typically are normal.
Indications for treatment in patients with Scheuermann kyphosis typically mirror the presenting complaints, namely pain, progressive deformity, neurologic compromise, cardiopulmonary issues, or cosmesis. Tailor the recommended treatment to the individual and base treatment not only on the severity of symptoms but also on the correlation between symptoms and the deformity. Additionally, in making decisions regarding treatment options, the physician must understand the natural history of Scheuermann kyphosis. Generally, the degree of clinical problems mirrors the magnitude of the deformity. Therefore, expect patients with mild deformities to have mild clinical symptoms. Murray et al reported the natural history and long-term follow-up of patients with Scheuermann kyphosis. They monitored 67 patients with a mean kyphotic angle of 71° for an average of 32 years. Patients with Scheuermann kyphosis had more intense back pain, typically localized to the thoracic spine, and overall had less demanding jobs and less mobility in the thoracic spine. However, both the patients with Scheuermann kyphosis and the age-matched controls also were found to have similar levels of education, absenteeism from work, physical activity, medication use, and social interactions. Other authors have presented a higher prevalence of problems in patients with Scheuermann kyphosis. Bradford reported a 50% incidence of severe thoracic back pain in his patients with thoracic deformities and a higher incidence of back pain in patients with thoracolumbar deformities. Lowe et al reported a high correlation between low back pain and severe thoracic deformity. Despite varying opinions on the natural history of Scheuermann kyphosis, there does appear to be a subset of adult patients who develop refractory pain. Knowing that a subset of adolescents who have progressive curves eventually develop painful deformities in adulthood affects treatment decisions earlier in life. The additional psychosocial effect of the deformity also must be considered. Neurologic and cardiopulmonary risks are exceedingly low, and, when encountered, they must be addressed on an individual basis.
Relevant Anatomy: The anatomy relevant to patients with Scheuermann kyphosis depends on the planned treatment. Surgical care for patients with Scheuermann kyphosis can be through a posterior, anterior, or a combined anterior and posterior approach (see Intraoperative details). Contraindications: Contraindications to treatment in patients with Scheuermann kyphosis are relative. Any treatment option must be balanced with risks and benefits for the individual patient. The magnitude of surgical intervention must be balanced with the perceived benefit and risk. Surgical care for patients with severe thoracic deformities is a large undertaking, and medical comorbidities must be considered. Neurologic compromise as a result of surgical intervention is the most catastrophic complication compatible with life that exists in treatment of patients with Scheuermann kyphosis. The incidence of neurologic compromise increases in revision spinal surgery, particularly with revision anterior approaches. Previous history of pulmonary compromise is a relative contraindication for an anterior approach. This should include previous history of empyema, which may complicate the surgical approach. Although no absolute contraindications exist to the surgical care of patients with Scheuermann kyphosis, the magnitude of the clinical problem and pervasiveness of the symptoms in the patient's life must be matched by the radiographic deformity and the surgeon's personal expertise. |
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Lab Studies:
Imaging Studies:
Medical therapy: Confirming the diagnosis of Scheuermann kyphosis does not mandate any specific treatment plan. Tailor treatment to the individual patient based on severity of the symptoms, age of the patient, and nature of the curve. The diagnosis should be confirmed and the history of the problem discussed with the patient. Observation may be the most reasonable treatment plan with no change in activity levels and simple radiographic follow-up. If the curve is progressive or symptomatic, additional treatment measurements are available. Anti-inflammatory medications Anti-inflammatory medications can provide reasonable short-term pain relief in the adolescent and may be considered for long-term use in the adult with symptomatic Scheuermann kyphosis. Obtain serial laboratory tests to monitor renal and liver function. Physical therapy Physical therapy should not be used with the thought of altering the natural history of a progressive kyphosis. However, a thoracic extension program and generalized conditioning program can be useful to aid in reducing symptoms. The program should be catered to the patient's clinical problem. Adults with Scheuermann kyphosis often develop lumbar spondylosis and mechanical low-back pain below the deformity. A spinal stabilization program, perhaps even with a flexion component, may prove to be useful in this patient population. Bracing Adolescents with progressive Scheuermann kyphosis early in their growth spurts and whose curves reach a threshold of at least 45° are ideal candidates for bracing. The brace must be high enough to affect forces proximal to the deformity. This typically necessitates a Milwaukee style brace with a neck ring, pelvic girdle, and connecting rods with a pad overlying the posterior apex of the kyphosis. Employ great vigilance in both brace fitting and subsequent follow-up. Obtain lateral radiographs at the time of initial bracing to confirm the adequacy of bracing correction. Continue follow-up at 3- to 6-month intervals to ensure that the brace is still producing a positive effect. As the patient continues to grow, the braces likely will need to be replaced. Bracing is continued until skeletal maturity is reached, and then a weaning process is begun. Lateral radiographs are performed during the weaning process and subsequent to the weaning process to monitor the potential loss of correction. Partial correction in patients who are skeletally mature and who underwent bracing therapy has been documented. Generally, bracing for adults with Scheuermann kyphosis is not recommended. Bracing in this patient population typically is poorly tolerated with poor patient compliance, secondary to brace discomfort, lack of objective improvement, and lack of a specific endpoint. In patients with severe refractory pain and deformity, bracing may be used to control discomfort in patients who are not surgical candidates and who otherwise are refractory to medical management. Surgical therapy: Once a patient with Scheuermann kyphosis, either adult or adolescent, reaches a surgical threshold, the goals for surgery are similar. These goals are to obtain a solid arthrodesis throughout the length of the kyphosis with appropriate correction of the deformity, alleviate pain, and improve spinal alignment. Surgical options include a posterior-alone approach, an anterior-alone approach, and a combined approach using both anterior and posterior techniques. Single approaches, either anterior alone or posterior alone, typically are reserved for deformities that exhibit partial ability for correction on a hyperextension film, with the deformity being reduced to less than 50°. Combined approaches typically are mandated for curves of 75° or more that do not correct to less than 50° on hyperextension lateral radiographs. The anterior-alone approach is the least commonly used approach for the correction of Scheuermann kyphosis. This approach initially was described by Kostuik and uses an interbody fusion technique with a Harrington distraction system. Kostuik reported on 36 patients with a mean preoperative deformity of 75.5° and demonstrated surgical correction maintained at follow-up with a deformity averaging 60°. The posterior-alone and combined anterior and posterior approaches are described more widely in the literature. The posterior-alone approach has the advantage of offering a single approach, which reduces total blood loss and avoids the risk of a thoracotomy. However, in the absence of an anterior release, the degree of correction obtainable by a posterior approach is lower than that of a combined approach. Additionally, the pseudoarthrosis rate would be predictably higher in a posterior-alone approach when compared to a combined approach. A combined approach is necessary for severe deformity correction. This also offers a higher rate of fusion than does a single-sided approach. The combined approaches typically are performed under the same anesthetic, depending on surgeon's preference. The anterior release is performed first through a thoracotomy, either open or thoracoscopically assisted, and this is followed by the posterior instrumented approach, which effects the correction of the deformity. Preoperative details: Preoperative planning for the patient with Scheuermann kyphosis is critically important. A detailed discussion with the patient and family members is conducted to prepare them for the magnitude of the operation and to discuss expectations of the rehabilitative process in the postoperative period. Conveying the specific risks involved with the operative procedures is also important so that a thorough understanding and informed consent is obtained. The treating physician must first decide on the operative technique, either a single-sided approach or a combined approach. Additionally, concomitant medical conditions must be considered and incorporated into the operative plan. For example, if concomitant thoracic stenosis is present, a decompressive procedure is indicated. Additionally, if a coexisting coronal deformity is present, this would impact the side of the anterior approach. Generally, approaching the deformity from the convexity is recommended. This facilitates the exposure, as the local vasculature tends to migrate towards the concavity. Finally, take great care in determining fusion levels. To determine overall sagittal balance, a plumb line is dropped from the C7 vertebral body to the sacral promontory. Sagittal balance is deemed positive when the plumb line falls anterior to the sacral promontory, and, conversely, it is deemed negative when the plumb line falls posterior to the sacral promontory. Patients with Scheuermann kyphosis frequently have negative overall sagittal balance. This often is exacerbated by surgical correction, particularly if the surgeon is overzealous in the technique. The risk of overcorrection leads to junctional kyphosis, either proximal or distal, to the fused segments. To avoid this complication, the fusion should extend approximately to the end vertebral body and distally beyond the end vertebral body to the first lordotic disk. The surgeon also should avoid overcorrection, with correction not exceeding 50% of the initial deformity and residual kyphosis exceeding 40°. Intraoperative details: Posterior approach
The levels to be addressed in the surgical approach must be determined on preoperative x-ray evaluation.
With a patient well padded in the prone position, a midline approach is created to the thoracic spine. An incision is created with skin knife, and dissection can be taken down through the subcutaneous tissues with electrocautery. A marker is placed over the first available thoracic spinous process, and a radiograph is obtained to confirm the appropriate level. It is best to choose the inferior aspect of the incision to mark the spinous process, as the radiograph can incorporate both the pelvis and the marked vertebral body, thereby facilitating the counting of appropriate levels.
A subperiosteal dissection ensues, stripping all of the perispinal muscles from the midline to lateral. Dissection is taken out all the way posterolaterally to the transverse processes of each respective level.
The posterior anatomy and landmarks of the vertebral bodies in individuals with Scheuermann kyphosis are fairly normal. The options for fixation include sublaminar hooks, transverse process hooks, pedicle hooks, and transpedicular screws. Any of these fixation devices then can be attached to a rod device. Take great care in contemplating sublaminar hooks, as staying out of the spinal canal is advisable.
Transpedicular fixation can provide excellent strength, but judicious use in the thoracic spine of transpedicular fixation is advised. Cross-sectional pedicular diameter makes transpedicular screw fixation technically challenging from T9 proximal, as pedicle diameter narrows considerably. The pedicular starting point for posterior placement of transpedicular screws is relatively proximal on these cephalad thoracic vertebral bodies.
Consider preoperative CT scan to assess pedicular diameter. Laminotomies may be performed to confirm medial or inferior violation of the pedicle during the placement of screws. However, cross-sectional pedicular diameter from T10-12 is more favorable for transpedicular fixation. Screws placed at these levels can provide an excellent base for the construct with a combination of pedicular and transverse process hooks proximally.
Hardware prominence also is particularly problematic in the thoracic spine, especially in thinner patients. Take great care in re-apposing the paraspinal muscles in the midline covering the hardware.
Anterior approach
The anterior approach to the thoracic spine often proves to be more challenging in patients with Scheuermann kyphosis. A standard posterolateral approach with single-rib resection is a useful approach to the thoracic spine from T4-12. If scoliosis coexists with the Scheuermann kyphosis, the incision typically is created to approach the convexity of the deformity. However, if no coronal deformity is present, the approach may be either from the patient's right or left, depending on surgeon preference and on the local vascular anatomy, which must be assessed preoperatively.
Take great care in planning the incision. Patients with Scheuermann kyphosis have more horizontal rib orientation, which must be considered when addressing the appropriate levels to be exposed.
Once the incision is created, the dissection is taken down through the subcutaneous tissues. The first muscle layer encountered is the latissimus dorsi, which crosses the incision anterolaterally, while the trapezius is located more posteriorly. Typically, these muscles must be incised in line with the incision to effect a wide exposure to the anterior thoracic spine.
Underlying these muscles is the serratus anterior. In the lower thoracic spine, the serratus anterior can be reflected proximally. In the upper thoracic spine, it must incised in line with the incision.
The level of the selected rib then is palpated. To facilitate an uncomplicated approach, take great care to confirm the appropriate rib to be resected. This may be confirmed by palpation from proximal or distal or confirmed by radiographic evaluation. The rib is subperiosteally exposed, sparing the neurovascular bundle on the inferior aspect of each respective rib. The rib is resected anteriorly and posteriorly as far as the incision will allow, and the chest then is entered by incising the pleura. The lung then can be retracted. For high thoracic approaches, a double lumen endotracheal tube is recommended to allow deflation of the lung. For midthoracic and lower-thoracic approaches, a single lumen tube is adequate.
The vertebral column is palpated, and a longitudinal incision is made in the prevertebral pleura to expose the vertebral column. The segmental vessels then are identified. These lie in the waists, or valleys, of the vertebral bodies, in contrast to the disks, which correspond to the peaks of the thoracic spine. If an anterior release with an interbody fusion is planned, it is possible to leave the segmental vessels intact. However, if vascular ligation is indicated, either for instrumentation or for wider visualization, they may be resected at the middle aspect of the vertebral body.
Temporarily applying a vascular clip to the segmental vessels without ligating the vessels has been recommended. This is followed by somatosensory evoked potential (SSEP) monitoring to ensure that the patient remains neurologically intact prior to ligation. However, Winter et al reported more than 1200 patients undergoing an anterior spinal approach with vascular ligation with only one neurologic event that was not directly attributable to mechanical causes.
With the vertebral column exposed and the appropriate level confirmed radiographically, discectomies and anterior release are performed over the apex of the deformity. Patients with Scheuermann kyphosis, by definition, have disk space height narrowing and wedged vertebral bodies with thickened and tightened ALLs. This anatomic fact makes an anterior release technically challenging.
A complete release of the ALL is necessary with complete resection of each disk to allow for subsequent maximal correction of the deformity. Occasionally, using an osteotome or burr is necessary to complete the discectomy, particularly in severe deformities.
A complete annulotomy around the entire vertebral body is necessary to effect a wide release. The relevant anatomy to the anterior spinal column is the aforementioned segmental vessels. The segmental arteries are direct branches off of the descending thoracic aorta, while the segmental veins drain directly into the ascending vena cava. The thoracic synthetic trunk and intercostal nerves also are readily visualized cascading along the anterior thoracic column and running from the costal grove on the inferior aspect of the rib directly to the vertebral foramen respectively. Additionally, take care to avoid injuring the thoracic duct and lymphatic system.
Combined anterior and posterior approach
The patient should be transferred to the operating room and placed on the operating table in a supine position. General anesthesia should be established. Use of a double-lumen endotracheal tube typically is not necessary, unless the patient is particularly small or the proposed anterior approach is proximal to T6.
After general anesthesia has been established, neurologic monitoring should be established. SSEP or motor-evoked potentials may be used. If neurologic monitoring is not available, a wake-up test is indicated.
The patient is then positioned laterally to perform the thoracotomy. Lieberman et al reported on a simultaneous anterior and posterior approach, with the patient positioned prone and the thoracoscopic anterior release being performed while the posterior exposure was being performed simultaneously. However, for this discussion, an open anterior release in the lateral position is described.
The incision must be planned with great care. The preoperative lateral x-ray gives the surgeon an idea of the obliqueness of the thoracic ribs. Patients with Scheuermann kyphosis often have more horizontal angles to their ribs, and this must be considered when planning the incision. The goal is to approach the deformity to its most severe levels, obtaining a complete anterior release of the apex of the deformity.
A right-sided approach avoids the great vessels. If a left-sided approach is contemplated due to a concomitant coronal deformity or for surgical preference, an MRI is useful to assess the local vasculature preoperatively. A posteriorly located descending aorta can obstruct the surgeon's approach to the thoracic spine.
A standard thoracotomy is used. The surgeon may elect to use a muscle-sparing approach through a more limited incision if the number of levels indicated in the anterior release is 4 or less. A rib-resecting approach facilitates a wider exposure and also provides for a local bone graft. Once the chest is entered, the lung is displaced proximally and anteriorly, or it is deflated when a double-lumen tube is used.
The pleura overlying the thoracic spine is incised longitudinally, and segmental vessels are identified. Treatment of the segment vessels is widely debated. Options include sparing the segmental vessels or ligating them. An intermediate approach is to temporarily occlude the segmental vessels with vascular clips and monitor the SSEPs to ensure that they do not change from baseline before proceeding with ligation of the segmentals.
The critical step in the anterior approach is to effect a wide release. The local vasculature must be protected while a complete discectomy is performed, including resection of the thickened ALL. The goal is a complete 270° release of the annulus to radically mobilize the disk space.
The surgeon then may proceed with the interbody fusion. Options are to perform a structural interbody fusion using the rib graft or to create a trough in the lateral aspect of the vertebral bodies and replace the morselized bone graft into the trough and interbodies. This creates a single column of morselized graft that is maintained during posterior manipulation and correction.
The pleura of the thoracic spine then is closed with a running suture to control blood loss and graft dislodgement. A chest tube is placed prior to closure, and the lung is reinflated under direct visualization. A standard closure then is effected, and the patient is repositioned for the posterior procedure.
The posterior procedure consists of a meticulous subperiosteal exposure of all posterior elements throughout the levels to be incorporated in the fusion. The hardware armamentarium includes hooks and screws with segmentally fixed rods. Hook options include transverse process hooks, sublaminar hooks, and pedicle hooks with the preference toward fixation that remains out of the spinal canal.
The 2 basic instrumentation techniques that effect posterior correction of the kyphotic deformity are the compression technique and the leverage technique.
A meticulous bone grafting technique must be used, particularly in adult patients with autogenous bone graft remaining the criterion standard.
Should intraoperative monitoring change from baseline, this must be explained. If no explanation is readily available, a wake-up test is indicated. If the wake-up test proves to be positive, all instrumentation should be removed to allow the spine to relax toward baseline. Generally, it is recommended at this juncture to proceed with closure and postoperative evaluation for the cause of the underlying neurologic change. Following this, subsequent corrective surgery can proceed if indicated. Postoperative details: The patient's hemodynamic and neurologic status must be monitored closely in the early postoperative period. In an uncomplicated recovery, the patient is mobilized and out of bed on the first postoperative day. The surgeon must determine whether a postoperative brace is necessary. Good quality bone and stable segmental fixation generally makes postoperative bracing unnecessary.
Physical therapy is necessary in the early postoperative period to reestablish ambulation and gait training, to facilitate mobilization out of bed, and to ensure proper hygiene. A standard regimen for chest-tube care is used with serial postoperative chest x-rays, monitoring of chest tube output, and, ultimately, chest-tube removal on the second or third postoperative day with an x-ray after chest tube removal.
The patient is discharged from the hospital after the patient is hemodynamically stable, has reasonable pain control on pain pills, resumes normal bowel habits and diet, the wound is clear and dry, and the patient resumes independence in ambulation and transfers in and out of bed. Discharge typically occurs around the fourth to sixth postoperative days. Standard postoperative instructions include wound care and expectations for rehabilitation. Generally, no specific physical therapy program is instituted, but the patient is instructed on daily walking and resumption of normal activities. The patient is cautioned against lifting, bending, twisting, or any athletic endeavors until further notice. Follow-up care: Follow-up for patients who have undergone surgical correction for Scheuermann kyphosis consists of clinical and radiographic evaluation. Clinical evaluation should include assessment of progress in terms of returning to normal activities and guidance of these activities.
Generally, patients are able to resume fairly normal activities of daily living within the first 4-6 weeks. Resumption of more physical activities occurs at 3-4 months. Radiographic evaluation depends on surgeon preference, yet a reasonable regimen might include radiographs at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperatively.
The patient should be making steady clinical and radiographic progress during this time frame, and any deviation from expectations should be evaluated. The treating physician must maintain a high concern for hardware failure and pseudoarthrosis, as these may have fairly indolent clinical presentations.
Radiographic evaluation should assess not only the fusion and correction, but also the sagittal and coronal balance and the junctional levels above and below the fusion.
Complications in patients undergoing extensive reconstructive spinal procedures are well documented. The complication rate is higher for adult patients than for adolescents. Categorically they are similar. Documented complications include death; neurologic compromise; hardware failure; pseudoarthrosis; pulmonary, chest-tube, and thoracotomy complications; blood clots; pulmonary emboli; wound infections; dural tears; and positional and anesthetic complications. Anticipation and vigilance in the identification and treatment of these potential complications are critically important.
Outcome and prognosis depend on the individual patient and treatment rendered. Generally, a patient with moderate to mild Scheuermann kyphosis rarely requires surgery or even bracing. These patients can be managed with education, guidance, and overall encouragement to resume and maintain normal activity levels. The aggressive use of exercise and judicious use of anti-inflammatory medications can augment this regimen. The outcome and prognosis of bracing treatment is more controversial. While the brace is in place, approximately a 50% correction of the deformity should be expected. However, once the brace is removed, a gradual loss of correction is expected over time. Sachs et al reported on 120 patients reviewed 5 years following discontinuation of bracing. Sixty-nine percent of these patients had maintained at least 3° of improvement over their presenting radiographs. Other authors have presented similar results. Sachs also reported that the prognosis was less favorable if the presenting curve was 74° or more. One third of these patients failed bracing therapy and progressed to needing surgery. The current literature is devoid of patient-based outcome studies in patients who have undergone surgical correction of Scheuermann kyphosis. While authors report high satisfaction rates, no papers have adequate control subjects. However, retrospective reviews with high patient satisfaction ratings should not be ignored. Surgical correction of the deformity affords predictable restoration of normal thoracic kyphosis, thus halting progressive deformities. Reasonable pain relief and resumption of normal activities also are reflected in multiple retrospective reviews.
Current controversies in the treatment of patients with Scheuermann kyphosis revolve around bracing care and the surgical decision making process. Proponents of bracing state that bracing postpones indefinitely the need for surgical intervention. Bracing nihilists believe that bracing does not affect the ultimate prognosis of the curve and that, if these patients are monitored long enough, the curve continues to settle and resumes its prebracing course of progression. Surgical care for patients with Scheuermann kyphosis also is somewhat controversial. Murray et al reported on 76 patients with a mean kyphosis angle of 71°, monitored for an average of 32 years. None of these patients underwent operative treatment. In comparing their quality of life to age-matched controls, no significant differences were encountered in level of education, number of days absent from work due to low-back pain, extent of pain that interfered with activities of daily living, presence of numbness in the lower extremity, self- consciousness, self-esteem, social limitations, use of medications for back pain, or level of recreational activities. However, these patients did report more intense back pain. They also tended to have jobs with lower requirements for physical activity. They had less range of motion and reported a different localization of their pain. This study has been criticized because of its lack of a surgical patient population as a control. Additionally, the average of 71° generally was deemed low compared to surgical groups. The future of the care for patients with Scheuermann kyphosis will mirror the evolution of the generalized care of patients with spine abnormalities. Dynamic instrumentation systems are being used, and improving surgical techniques with biological manipulation are almost certain to become mainstream treatment options.
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