Surgical complications of posterior lumbar interbody fusion with total facetectomy in 251 patients SHINYA OKUDA, M.D., etc… Department of Orthopaedic Surgery, Osaka Rosai Hospital, Osaka; and Department of Orthopaedic Surgery, Hyogo, Japan J Neurosurg Spine 4:304–309, 2006 JOURNAL READING 2006, 4,11 PRESENTED BY P.E.HUNG

Introduction-- To treat degenerative lumbar disorders with segmental instability, it is essential to decompress all involved neural elements and stabilize the affected segment.

The PLIF provides wide posterior visualization and circumferential decompression of the neural elements

Introduction-- Although PLIF with pedicle screw fixation (TPS) has produced satisfactory clinical results, it is associated with surgical complications.

Introduction-- Several reports indicate lumbar arthrodesis have substantially higher complication rates than decompression alone. Previous studies of surgical complications are of limited value due to variation in instrumentation and fusion techniques.

Purpose and Methods-- To examine intraoperative, early postoperative, and late postoperative complication rates of PLIF Using a large number of cases with uniform instrumentation and a uniform fusion technique. Reviewed the records of 251 patients who underwent PLIF for degenerative lumbar disorders between 1996 ~ 2002 and who could be followed for at least 2 years.

Clinical Material-- F/U rate 88%. Mean age at surgery :61 Y/O Mean F/U period: 50 months Diagnosis: Most(154) of the patients degenerative spondylolisthesis 53 isthmic spondylolisthesis 23 lumbar canal stenosis 21 disc herniation Exclude infection, fracture– dislocation, rheumatoid arthritis, or destructive spinal arthropathy. The vertebral levels of the PLIF segments were as follows: L1–2 in 2 cases L2–3 in 5, L3–4 in 18 L4–5 in 162 L5–6 in 12, and L5–S1 in 39 In 13 patients, two levels were fused: L2–4 in 2, L3–5 in 10, and L4–S1 in 1.

Clinical Material— Indications: Severe, disabling low-back pain and lower-extremity pain that were unresponsive to conservative treatment such as medication and epidural steroid injection. Spondylolisthesis with slippage greater than 3 mm and a posterior opening greater than 5° on flexion– extension lateral radiographs. Lumbar canal stenosis, or disc herniation requiring wide decompression and discectomy.

Clinical Material— Procedures & Technique: By five surgeons, each had more than 10 years of experience in orthopedic surgery. Using the Steffee variable screw placement system and local bone grafting with Brantigan interbody fusion cages. Total facetectomy was performed to prevent excessive retraction of neural elements during discectomy and bone grafting.

Clinical Material— Procedures & Technique: Autografting was performed using local lamina bone. Neither fluoroscopic guidance nor computer navigation was used during the pedicle screw insertion. Posterolateral fusion was not added at any level.

Clinical Material— Assessments: JOA scoring system(29 to -6). Timimg: before surgery and at 1, 3, 6, 12, 15,18, and 24 months post-op. Early postoperative-- occurring less than or equal to 1 month. Late postoperative--greater than 1 month. Excluded complications that were not specific for spine surgery and did not affect recovery(for example, urinary tract infection, anemia, and confusion) Spine-specific complications (such as pedicle screw malpositions) were included even if they did not affect postoperative clinical results.

JOA scoring system(29 to -6)

Investigation-- Intraoperative complications dural tearing, nerve injury (for example, cauda equina and/or nerve root damage); pedicle screw malposition(penetration of the medial or lateral pedicle cortex by more than half the diameter of the screw or penetration of the anterior vertebral cortex by more than 5 mm of the screw tip) Early postoperative complications pulmonary, cardiac, and cerebrovascular morbidity; infection; hardware failure; and neurological complications classified into three categories: ( leg pain/severe/slight motor loss) Late postoperative complications late infection, hardware failure, nonunion, and adjacent-segment degeneration.(defined as a condition in which additional surgery was required) If solid fusion was not detected 6 months after surgery, a conventional and reconstruction CT study was performed every 3 months to confirm bone continuity between bone graft and vertebra.

Summary of the results--

Clinical issue-- Intraoperative complications Intraoperative complications did not affect the postoperative clinical results. One (1/7) patient with irritation of the nerve root due to medial penetration of the pedicle screw underwent revision surgery, then s/s improved. No other patient had symptoms due to pedicle screw malposition.

Clinical issue-- Early postoperative complications One case with brain infarction was observed 2 days after surgery, successfully treated with conservative therapy One case, CRF due to DM under H/D, deep wound infection was noted about 1 week after surgery, debridement three times, improved without hardware removal. 8 p’t with slight motor loss or radicular pain alone, their symptoms improved within 6 weeks. 9 p’t showed severe motor loss such as foot drop; compression of neural elements was not detected on image; 5/9 agreed to receive 2 nd op( average period 9 days ; 2/5 expansion of hemostatic agents; 1/5 epidural hematoma; 1/5 inadequate decompression around the nerve root; 1/5 unknown) JOA(before first op and after 2 nd op)=10  21 JOA(not revision surgery)=10  12(with permanent motor loss)

Clinical issue-- Late postoperative complications All 3 patients with hardware failure exhibited pedicle screw breakage, but none of them had complaints, bone fusion was detected in all. Nonunion, 2/3 had severe low-back pain that was unresponsive to conservative treatment for more than 1 year and was treated with a 2 nd op, average period 17 months

Postoperative progression of adjacent-segment degeneration It was observed at the cranial segment in 9/11 cases and at the caudal segment in 2/11 cases. The average JOA (before first op/before 2 nd op/max. after 2 nd op)  13/14/25 2 nd OP-- 6 laminotomy, 4 PLIF, 1 discectomy. All 11 p’t had improvement of neurological symptoms. The average period: 24 months

Discussion-- Intraoperative complications Dura-related complications are often considered of little consequence to the final outcome, as was the case in the present series. The incidence of pedicle screw malposition should be reduced by development of computer navigation systems.

Discussion-- Early postoperative complications Total facetectomy can provide more space for PLIF maneuvering and can facilitate retraction of nerve roots to prevent nerve injury. In the current series, all patients with severe motor loss exhibited neurological deficits for a few days after surgery. Therefore, we conclude that intraoperative nerve injury was not the cause of these neurological deficits. In cases severe motor loss occurs a few days after PLIF, surgical intervention should be performed to confirm decompression of the nerve roots, even if it is not detected on postoperative neuroimages.

Discussion-- Late postoperative complications Hardware failure was likely to increase if more fusion levels are involved, but it did not affect clinical results. The causes of these nonunions were not indicated by the patient’s history or laboratory data. We achieve an extensive bone graft area in the disc space by total facetectomy and extensive discectomy at the lateral border. Such techniques increased the fusion rate to 99% in the present series.

Discussion-- Late postoperative complications Adjacent-segment degeneration It tended to occur at the cranial segment, producing the same conditions(7/11 had the same Dx) as those seen at the first operation. Although progression of this degeneration can be considered part of the normal aging and deterioration process, this phenomenon appears to be at least partly influenced by the alteration of stresses. Risk factors: addition of instrumentation, injury to the adjacent facet joint, fusion length, and sagittal alignment, coexistence of facet tropism and lamina horizontalization adjacent to the fusion segment.

Related article Radiologic Evaluation of Adjacent Superior Segment Facet Joint Violation Following Transpedicular Instrumentation of the Lumbar Spine. Spine. 28(3): , February 1, Abstract: Study Design. The location of pedicle screws in relation to adjacent superior segment facet joints in 106 patients after lumbar spinal fusion was assessed using computed tomography and plain radiographs. Conclusion. Facet joint violation occurred in just >30% of the patients and 20% of the screws in this study. This, therefore, raises the theoretical possibility of long-term deterioration in the clinical results following the use of transpedicular instrumentation.

Related article Adjacent Segment Disease after Lumbar or Lumbosacral Fusion: Review of the Literature. Spine. 29(17): , September 1, Definition, etiology, incidence, and risk factors, potential treatment options. Conclusion-- Biomechanical alterations likely play a primary role Radiographically common but does not correlate with functional outcomes. Potentially modifiable risk factors include fusion without instrumentation, protecting the facet joint of the adjacent segment during placement of pedicle screws,fusion length, and sagittal balance. Surgical management, when indicated, consists of decompression of neural elements and extension of fusion. Outcomes are modest.

Conclusions-- Of the 251 patients whose cases we reviewed, 62 (25%) exhibited one or more complications, and 20 (8%) underwent a 2 nd op. There was no relationship between complications and a specific cause such as the size of the cage, age, diagnosis, or a specific surgeon. In the present study, the most serious complications of PLIF were postoperative severe neurological complications and adjacent-segment degeneration. Prevention and management of such complications are necessary for obtaining good long-term clinical results.

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