Kümmell disease is a specific condition of vertebral compression fractures,which is a typically manifestation of failed fracture healing process, and conservative treatments are usually ineffective. Although the optimal therapeutic methods remain controversial, surgical interventions are still needed to control the refractory pain or kyphosis. Though the optimal therapeutic methods remain controversial, surgical interventions are still needed to control the refractory pain or kyphosis. Various surgical procedures have been proposed for the management of Kümmell disease, such as PVP or PKP, which have satisfying effect to relieve clinical symptoms and improve functional status (10, 11). However, stage III Kümmell disease is more challenging for orthopaedic surgeons, because these patients have broken posterior cortex and obvious intravertebral instability. Conventional PVP or PKP could neither reconstruct the intravertebral stability nor contribute to the union of fracture, and the risks of cement leakages during the operation or the needs of revision surgery to remove the dislocated polymethylmethacrylate (PMMA) cement might lead to much more damages to the elderly patients(7, 12).Moreover, due to the loading shifts of adjacent vertebra, subsequent risks of vertebral fracture are high;And impaired nutrient supply to the disc due to the heat released by PMMA might induce degenerative changes in the adjacent disc, complicating the existing situation (13, 14).
For advanced Kummell disease, most surgeons choose open surgery to decompress spinal cord and stabilize the spine, however, current surgical options are complicated and risky for these patients. Both of anterior reconstruction (AR) and posterior osteotomy (PO) are common treatment methods for the situation mentioned above, of which AR approach could resect the bony fragments and provide anterior column support and PO approach could dissect the cortex by posterior spinal shortening osteotomy and correct kyphotic deformity. However, there are many disadvantages, such as AR approach might detach the diaphragm or open either the thoracic cavity or the retroperitoneal space, which could compromise lung function or injure the internal organs; longer operation time; cause of kyphosis due to vertebral body or graft re-collapse(9). In view of patients’ advanced age, serious comorbidities and severe osteoporosis, AR approach is inappropriate for these individuals because of its high risks and invasiveness. In contrast, most surgeons are more familiar with the posterior approach. PO and fixation can provide relatively secure fixation with less complications, and stable fixation could help early mobilization with lower incidence of implant-related complications, such as loose screw, screw fracture and screw disconnection (15). However, Osteotomy is a challenging and complicated procedure that requires delicacy and surgeons with more experiences (6). Any error around the spinal cord or medullary cone would be dangerous and might lead to nerve impingement or dural tear (16).
A successful surgical procedure for treating advanced kummell disease in elderly patients must consider the biological and biomechanical factors of this condition. Autologous or allograft bone should be implanted after thoroughly removal of the necrotic bone tissues, so that to promote osteogenesis and angiogenesis. On the other hand, better mechanical support of the collapsed vertebral body and good fixation are required to maintain the biomechanical stability.
In this case, we reported a detailed approach of transpedicular interbody cage insertion with posterior spine stabilization to treat stage III Kümmell disease in elder patient. A similar approach by Mei L (8) et al were reported in the literature. They used a series of transpedicular body augments (a titanium spacer with bone-ingrowth porous surface) to treat Kümmell disease with cord compression (III stage), and successfully restored body height and corrected kyphosis. Although there are different sizes of the augments available, their method has not been used widely and commonly in clinical practice. The custom-made tools that were needed for their method were hard to obtain for others. Although the porous surface of the augments might contribute to bone ingrowth, the shape of the augments can’t prevent itself from slip backward and it might not maintain stability in the implanted cancellous bones during the earlier time postoperatively. In addition, their method required making bilateral pedicle tunnels of the fractured vertebral body, which might influence the stability of the spine to some extent. Likewise, another similar method reported by Lee SH (17) et al used two kinds of different shaped polyetheretherketone (PEEK) interbody cages, which are CRESCENT cage and CAPSTONE cage. The CRESCENT cages are comparatively expensive, and its shape limits the function of wedged expansion, compared to bullethead. Also, it is difficult to control the direction when inserting them. While CAPSTONE cages have weak bullet-shaped head and contain less amount of bone grafts, which might influence the insertion and bone fusion (Figure 6 B).
In this case, our modified approach with large enough space enables a sizeable cage to be inserted, and the carbon fiber-reinforced polyetheretherketone (CFRP) cages that we used here are widely in use clinically. This type of cage was initially designed for posterior lumbar interbody fusion (Figure 4A), where its wedged bullethead can facilitate cage insertion (Figure 4B), tine-teeth devise can help maintain stability, and tantalum beads enable conventional imaging methods for evaluation of bone fusion postoperatively (Figure 4A), allowing for better follow-up studies (18). In addition, CFRP fusion cages can accommodate much more graft material and larger contact surface than CAPSTONE cages (Figure 4C), which may improve fusion rates. Furthermore, CFRP implants have better biological and mechanical properties compared to titanium implants, which can transfer high stresses and forces efficiently due to their ability to sustain both tension and compression (19). And our approach is less invasive and the possible risks of injuring the nerve root could be reduced with surgeons of good skills and experience. Moreover, the reduction of the fractured vertebrae by this method is easier to achieve but must be with cautionary in patients with chronic conditions of fracturees or ossified posterior longitudinal ligament (20). Finally, this method has the least interference on blood circulation of intervertebral disc, the debridement of fracture sites and bone grafting might help the recovery of blood circulation of the disc, which prevent the degeneration of the disc[14]. The limitation of this method including the necessity to remove unilateral transverse process and part of the pedicle in order to insert a bigger cage to restore the height the compressed vertebra. However, this doesn’t affect the spinal stability because of the existence of posterior pedicle screw. Furthermore, we found that there is no need to remove the superior or the inferior cortex of the pedicle after proficiency, because the fractured vertebral body can easily be expanded via the wedge-shaped cage.