Revision Surgery for Postoperative Spondylodiscitis at Cage Level after Posterior Instrumented Fusion in the Lumbar Spine-Anterior Approach Is Not Absolutely Indicated

Treatment Concept and Technical Considerations of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis

Decompression is a major component of surgical procedures for degenerative lumbar spinal stenosis (LSS). In addition to sufficient decompression to guarantee the relief of neurological pain, compensating surgical instability after wider laminectomy and foraminotomy and instrumentation with caging and fusion with grafting are performed to secure or restore the foraminal dimension and correct coronal/sagittal imbalance for longer survival of the adjacent segment. Endoscopic spinal surgery (ESS) has been developed under the flag of successful decompression while preserving structural integrity as much as possible with the help of magnification and illumination. ESS provides a technical possibility and feasibility for solving LSS by decompression alone. Recently, many endoscopic trials have been conducted to overcome conventional surgical treatment that requires wider dissection, escape inevitable complications from surgical damage, and compensate for the fusion technique. However, biportal ESS has some technical limitations, including clinical difficulties in accessibility for more moderate to severe stenosis and challenges for complicated conditions with segmental ventral slip, isthmic defect, stenosis combined with foraminal stenosis or foraminal disk rupture, or degenerative segmental scoliosis with disk height collapsing and endplate fatigue fracture. Because decompression alone is a skill for eliminating pathologies, there is no function of preserving degenerative structure or stopping the recurrence of disk degeneration or subsidence. This review of clinical reports investigated the possibility of biportal ESS for treating degenerative lumbar disorders by sufficient decompression and adequate elimination of various pathologies and decreasing technical complications. The results of this study may help develop better innovative spinal surgical techniques in the near future.

Biomechanical investigation of the hybrid lumbar fixation technique with traditional and cortical bone trajectories in transforaminal lumbar interbody fusion: finite element analysis

OBJECTIVE

To compare the biomechanical performance of the hybrid lumbar fixation technique with the traditional and cortical bone trajectory techniques using the finite element method.

METHODS

Four adult wet lumbar spine specimens were provided by the Department of Anatomy and Research of Xinjiang Medical University, and four L1-S1 lumbar spine with transforaminal lumbar interbody fusion (TLIF) models at L4-L5 segment and four different fixation techniques were established: bilateral traditional trajectory screw fixation (TT-TT), bilateral cortical bone trajectory screw fixation (CBT-CBT), hybrid CBT-TT (CBT screws at L4 and TT screws at L5) and TT-CBT (TT screws at L4 and CBT screws at L5). The range of motion (ROM) of the L4-L5 segment, von Mises stress of cage, internal fixation, and rod were compared in flexion, extension, left and right bending, and left and right rotation.

RESULTS

Compared with the TT-TT group, the TT-CBT group exhibited lower ROM of L4-L5 segment, especially in left-sided bending; the CBT-TT group had the lowest ROM of L4-L5 segment in flexion and extension among the four fixation methods. Compared with the CBT-CBT group, the peak cage stress in the TT-CBT group was reduced by 9.9%, 18.1%, 21.5%, 23.3%, and 26.1% in flexion, left bending, right bending, left rotation, and right rotation conditions, respectively, but not statistically significant (P > 0.05). The peak stress of the internal fixation system in the TT-CBT group was significantly lower than the other three fixation methods in all five conditions except for extension, with a statistically significant difference between the CBT-TT and TT-CBT groups in the left rotation condition (P = 0.017). In addition, compared with the CBT-CBT group, the peak stress of the rod in the CBT-TT group decreased by 34.8%, 32.1%, 28.2%, 29.3%, and 43.0% under the six working conditions of flexion, extension, left bending, left rotation, and right rotation, respectively, but not statistically significant (P > 0.05).

CONCLUSIONS

Compared with the TT-TT and CBT-CBT fixation methods in TLIF, the hybrid lumbar fixation CBT-TT and TT-CBT techniques increase the biomechanical stability of the internal fixation structure of the lumbar fusion segment to a certain extent and provide a corresponding theoretical basis for further development in the clinic.

Treatment strategy for surgical site infection post posterior lumbar interbody fusion: A retrospective study

Introduction

Posterior lumbar interbody fusion (PLIF) has been widely used to treat various degenerative spinal diseases. However, surgical site infection (SSI) post-PLIF is often difficult to cure. This study aimed to clarify the difference in clinical course due to the causative organism and develop a treatment strategy for SSI post-PLIF.

Methods

Between January 2011 and March 2019, 581 PLIF surgeries were performed at our hospital. Deep SSI occurred in 14 patients who were followed up for more than 2 years. Causative bacterial species were diagnosed by preoperative puncture and/or intraoperative drainage or by tissue culture in 13 patients and by intradiscal puncture in one patient who underwent conservative treatment. Of the 13 patients who underwent surgeries for infection, 10 had Propionibacterium acnes (Group A; n = 4) or coagulase-negative Staphylococcus (CNS) (Group B; n = 6) as the causative bacterial species. Groups A and B were retrospectively compared in terms of age, sex, number of segments, presence of diabetes mellitus, operation time, blood loss, C-reactive protein on hematological examination, the elapsed time to diagnosis (ETD), the presence of clinical findings such as heat, redness, swelling, and discharge from the wound and healing time.

Results

All infections were eradicated with surgery except in one patient whose causative bacteria was CNS; cages were finally removed in 11 patients. There was a significant difference (P = 0.0105) in the ETD and clinical findings (P = 0.0476) between Groups A and B. Posterior one-stage simultaneous revision (POSSR) was performed in nine patients, of whom eight were cured and one required additional surgery.

Conclusions

The ETD and clinical findings were significantly different in SSI cases caused by different bacteria, which will be useful in predicting the causative bacteria in future cases. For the treatment of deep SSI post-PLIF, POSSR was effective.