Síntomas clínicos: reporte de un caso de revisión Fusión lumbar anterior-posterior después de TLIF
ABSTRACTO
Antecedentes: Se han utilizado numerosas técnicas quirúrgicas para el tratamiento de la enfermedad degenerativa del disco. El abordaje quirúrgico, tratamiento e implante de elección depende de la edad del paciente, calidad ósea, sitio de compresión, alineación, angulaciones vertebrales y preferencia del cirujano.
El siguiente informe de caso ilustra las posibles correlaciones entre técnica quirúrgica e implante de elección y resultados del paciente.
Método: Presentamos el caso de una mujer de 65 años que presentaba un L4/ Fusión intersomática lumbar transforaminal L5 (TLIF) y experiencia sin alivio de los síntomas después de la fusión.
Después de cinco años de regreso continuo y síntomas de las extremidades inferiores, optó por una revisión multinivel Fusión intersomática lumbar anterior posterior (AP).
Resultados: Posteriormente experimentó un alivio inmediato de síntomas. En el siguiente informe de caso, nosotros (1) investigamos la hallazgos clínicos e identificar posibles factores causales y (2) mitigar estos factores en la fusión circunferencial de revisión para mejorar la resultado del paciente.
Conclusiones: Con base en la literatura actual y los hallazgos de este caso, investigamos hundimiento, hipolordosis, escoliosis y pseudoartrosis en relación con las decisiones periquirúrgicas, por lo tanto, podemos comprender mejor la relación entre las opciones quirúrgicas y la sintomatología del paciente.
Continua en inglés:
Understanding The Potential Impact Of Procedure And Implant Choice On Postoperative Clinical Symptoms: A Case Report Of Revision Anterior-Posterior Lumbar Fusion After TLIF
Introduction
Various lumbar fusion options exist for the treatment of symptomatic degenerative disc disease. Surgeons choose the procedure, techniques, and implant based on their preferences and patient attributes. These attributes include bone quality, age, mobility, vertebral alignment, and angular deformity (1). There is a lack of literature investigating the relationship between surgical decisions, patient attributes, and patient outcomes. The following case report and review of current literature illustrate the possible implications of surgical and implant choices on patient symptomatology. We present a unique case where the same patient underwent an index transforaminal lumbar interbody fusion (TLIF) and a subsequent anterior-posterior (AP) lumbar interbody fusion for the same symptoms. By comparing the outcomes of each surgery, we are able to understand the impact of surgical technique and implant choice on patient outcomes.
Case Report
A 65-year old woman presented four years after having L4/L5 TLIF with an outside surgeon. The patient was a non-smoker and had a BMI of 30.2. She had no history of diabetes, osteoporosis, anemia, or auto- immune disease. She presented to the clinic of the secondary author with a fixed forward inclination of the trunk and a hyper-extended neck to keep her head erect. She had lower back pain at the level of the previous surgical site. Her primary complaint was radiating pain in her lower extremity when standing, walking, or sitting. Pain was exacerbated with hip flexion and knee extension during ambulation. Pain on the right side was worse than pain on the left side. When seated, she shifted her weight from side-to-side to mitigate the pain. With no activity, her baseline pain was 5/10 on the VAS. With ambulation, her pain was significantly worse.
She related that she had no change in symptoms from before to after the TLIF. However, the level of pain was greater in the months prior to initial presentation.
Physical exam revealed lumbar and buttock pain in the seated position and throughout ambulation. She had a maximal hip flexion of 60° with notable discomfort and a maximal hip extension of less than 5°. The Faber test and straight-leg-raise test elicited lumbosacral pain as well. She had no neurovascular deficit.
A 2-view radiographic series consisting of anterior-posterior (AP) and lateral radiographs was performed to assess the bony anatomy and vertebral alignment. The patient’s AP radiographs showed a mild left-sided scoliosis with the apex residing at the L1/L2 disc space (Figure 1A). This finding coincided with the patient’s exacerbated right-sided lower extremity pains compared to her left. While a left-sided convexity opened the neural foramen, the right-sided concavity narrowed the foramen. The coronal Cobb angle was measured to assess the extent of the scoliosis visualized. A radiolucent implant consistent with a polyetheretherketone (PEEK) spacer was noted within an asymmetrically narrowed L4/L5 disc space. The implant was subsided within the L5 vertebral body. The posterior instrumentation was noted with no pedicle screw loosening. Subchondral sclerosis and joint space narrowing was found within the sacroiliac joint.
The lateral radiographs showed hypolordotic changes throughout the lumbar spine (Figure 1B). The sagittal plane imbalance was confirmed via the following radiographic parameters: global lumbar lordosis angle and segmental lumbar lordosis angle. The global lumbar lordotic angle was defined as the angle created between the superior endplates of L1 and S1 using the Cobb method (2). The L3/L4 segmental lumbar lordosis
was the measured angle between the superior endplate of L3 and the inferior endplate of L4 (3). The L5/S1 segmental lumbar lordosis was the measured angle between the superior endplates of L5 and S1 (3). Grade 1 anterolisthesis (<25%) was identified with L3 anterior to L4 and L5 anterior to S1. Findings consistent with degenerative disc disease, including asymmetric disc space narrowing and osteophytic growth along sclerotic endplates, was found from L4 to S1. Anterior, middle, and posterior disc space heights of L3/L4, L4/L5, and L5/S1 were recorded using the standard technique (4). Sclerotic facet joints from L4 to S1 were hypertrophied with peripheral osteophytes. All radiographic morphometrics were measured and recorded by the authors (Table 1).
After undergoing conservative treatment modalities including years of physical therapy, numerous epidural steroid injections, and medications to treat her lower extremity pain, she opted to proceed with advanced imaging modalities to explore surgical options.
After conventional radiographs an MRI was performed to provide a detailed evaluation of the lumbar anatomy (Figure 2). The MRI showed an inhomogeneous low signal in the intervertebral discs from L2 to S1 of the T2-weighted images. These findings were consistent with disc dehydration and fibrous changes within the nucleous pulposis. A broad- based disc prolapse and narrowing of the spinal canal was noted at L3/L4 and L5/S1 disc spaces. Notable fibrous scar tissue was seen in the spinal canal from L4 to L5. Hypointense Modic endplate changes noted on the T1WI sequence characterized fibrosis of the subchondral interface. A notably high signal intensity within the hypertrophic L3/L4 and L5/S1 facet joints in the sagittal STIR sequence. indicated joint degeneration with subchondral sclerosis and intra-articular joint effusion. A hypertrophied ligamentum flavum was noted from L2 to S1 on the sagittal T2WI sequence. Neural foraminal stenosis with perineural fat obliteration surrounding the corresponding nerve root was visualized. All sagittal MRI sequences confirmed that the L4/L5 intervertebral implant was subsided in the central aspect of the L5 vertebral body. The implant was narrow, crescent-shaped, and seated at the anterior and central aspect of the vertebral body. Fibrous scar tissue was noted at the surgical site. Fat atrophy of the lumbar extensor muscles was noted from L2 to S1 on the sagittal T2WI sequence. These findings coincided with the clinical and radiographic findings.
Cross-sectional CT imaging was performed to provide a detailed assessment of the osseous structures and joint spaces from a multi- planar dimension (Figure 3). The sagittal CT scan confirmed grade 1 anterolisthesis of L3 on L4 and L5 on S1 on the sagittal CT views. Osteophytic growth, endplate sclerosis, and asymmetric disc space narrowing were noted in the L3/L4 and L5/S1 disc spaces. Subsequent
foraminal impingement was seen from L3 to S1. Corresponding facet joint hypertrophy with narrowing and subchondral cysts was noted. The L4/L5 hardware appeared stable with no loosening. Minimal bone growth was noted at the TLIF surgical site. The interbody device was consistent with PEEK and subsided in the body of L5 by 5.6 mm. The implant was narrow in the sagittal plane. The posterior hardware construct appeared to be intact. These findings were consistent with the patient’s clinical, radiographic, and MRI findings.
After a thorough pre-op discussion, the patient was informed in the detail of the procedure opted to have a multi-level fusion from L3 to S1. The surgical plan involved checking the stability of the L4/L5 hardware. If there was loosening in the posterior column instrumentation or the interbody device, the primary surgeon (secondary author) planned for removal with hardware replacement. The surgeon contacted the office of the patient’s previous surgeon and found the device currently implanted within the patient was a 7° ALEUTIN® TLIF PEEK implant (K2M, Leesburg, VA). The ALIF was performed in the standard technique using a retroperitoneal approach. An access surgeon was utilized. A L5/S1 discectomy was performed, and the end plates were prepared with curettage. A 15° lordotic titanium SPIRA® cage was implanted (Camber Spine, King of Prussia, PA). At the L4/L5 disc space, the PEEK implant was visualized. The implant was non-mobile and firmly impacted in the disc space. It was noted to be imbedded within the L5 vertebral body. Fibrous scar tissue was found circumferential to the implant. Minimal bone formation was noted. The scar tissue was resected. The disc space surrounding the implant was prepared with curettage.
Next, a L3/L4 discectomy was performed. After endplates were prepared, an 8° lordotic, titanium, SPIRA® cage was implanted (Camber Spine, King of Prussia, PA). Both cages and all three disc spaces were packed with bone morphogenic protein (BMP), bone marrow aspirate (BMA), and DBX® (Depuy Synthes, Raynham, MA). Anterior plates were utilized at the L3/L4 and L5/S1 spaces to ensure maximal stabilization. A posterior incision was made to apply the pedicle and rod fixation. Once the incision was deepened using the standard technique, the current posterior instrumentation at L4/L5 was visualized. The right-sided screws had good purchase. However, some loosening was noted on the left side. This finding correlated with the mild radiographic scoliosis noted with a left-sided convexity. The L4/L5 instrumentation was removed. The remaining holes were deepened and tapped. Then, replacement pedicle screws from the ORTHOS MIS™ pedicle screw system were applied from L3 to S1 (Camber Spine, King of Prussia, PA). Excellent purchase was noted at all levels including L4/L5. Laminectomies were performed from L2 to L4. Concomitant foraminotomies were performed at L4. FIBRINET® (Vertical Spine, Wall Township, NJ) platelet rich plasma (PRP), platelet-rich fibrin matrix (PRFM), BMA, and DBX® bone graft were applied to all fusion sites to augment fixation at each level. Once intraoperative fluoroscopy confirmed proper positioning of the hardware and improvement of the patient’s sagittal and coronal plane deformities, closure ensued using the usual technique.
The patient ambulated with a back brace in the immediate postoperative period and stated that her leg pain was significantly better. Two weeks into the postoperative period, she stated that her leg pain was non-existent. Her lumbar pain level was 3/10 on the VAS when standing or walking. At the 6-month postoperative exam, she had a negative Faber test and negative straight-leg-raise test. She had no pain when standing and walking. She
had an erect posture with no fixed forward inclination of the trunk. She had a level 1/10 pain only when crouching.
One-year postoperative radiographs showed cages in proper alignment with anterior and posterior instrumentation intact (Figure 4). Osseous growth was noted at all three fusion sites. To understand the long-term degree of correction, the same morphometric measurements taken pre-circumferential fusion were taken one year post-surgery (Table 1). Results showed improved disc height, restored lumbar lordosis, and reduced scoliosis. The average disc height of L3/L4 and L5/S1 pre- revision surgery was 8.1mm and post-revision surgery was 16.3mm, indicating a long-term gain of 8.2mm. The average disc height at L4/L5 pre-AP fusion was 6.5mm and post-AP fusion was 10.5mm, indicating a long-term gain of 4.0mm. The global lumbar lordosis angle improved by 11.2°, and the average segmental lumbar lordosis angle of L3/L4 and L5/S1 improved by 6°. These angles indicated a restoration of the lumbar lordosis. The coronal Cobb angle improved by 6.8° to 4.8° post-ALIF, indicating correction of the patient’s scoliosis.
Discussion
The patient exhibited completely different symptomatology after the index TLIF procedure and the revision anterior-posterior fusion. She experienced no relief of symptoms post-TLIF, but experienced near- immediate relief of symptoms after the circumferential fusion. The purpose of this case report is to explore contributive factors after the TLIF, assess mitigating factors post-anterior-posterior fusion, and correlate our findings with that of current literature.
Radiculopathy Secondary to Subsidence
The patient presented with radiating symptoms consistent with lumbar radiculopathy. These clinical symptoms may have been a result of the high-grade subsidence (5.6mm) seen on the CT scan. Surgical observation confirmed that a narrow, crescent-shaped PEEK implant was firmly wedged in the L4/L5 disc space and deeply subsided within the central aspect of L5 vertebral body. Studies show that the central aspect of lumbar endplates have weaker load-bearing capabilities in comparison to the posterior lateral aspects of the endplates (5, 6). This area of structural weakness corresponded with the area of subsidence in the present case. Additionally, the anterior and middle columns bear 80% of the spinal load, thus these areas are more likely to be injured
(7). Patients with high-grade subsidence are prone to developing radiculopathy from neural foraminal narrowing (8, 9). A marked loss of foraminal height is associated with peri-foraminal osteophytic formation, stenosis, and nerve root compression as seen in the current patient (8). Thus, the high-grade subsidence in the present case may have exacerbated the patient’s radiating lower extremity pain. In order to restore disc height and mitigate the risk of high-grade subsidence in the adjacent disc spaces, the primary surgeon (secondary author) chose wide, biconvex SPIRA® implants for the revision anterior- posterior fusion surgery. By mimicking the anatomic convexity of the intervertebral disc, the implants were better equipped to disperse the forces across a larger surface area compared to the original narrow PEEK implant. The immediate postoperative relief of symptoms and the improved disc height indicated successful foraminal enlargement and neural decompression across all levels.
Postural Compensation Secondary to Lumbar Hypolordosis
In addition to radiculopathy, the patient presented with hip and knee flexion and cervical and thoracic extension. She experienced severe pain with knee extension and mitigated the pain through flexion. The cervical and thoracic extensions were compensatory postural adjustments needed to maintain an upright stance (10, 11, 12). Radiographic images confirmed a sagittal plane lumbar lordotic loss otherwise known as flatback syndrome (10). Studies show that patients with flatback syndrome demonstrated the same postural changes exhibited in the current case (10, 11, 12). Failure to restore the lumbar lordosis propagates the adjacent segment disease (11, 12, 13). As seen in the present patient, lumbar hypolordosis causes accelerated degeneration of the adjacent disc spaces, fixed forward trunk inclination, and a domino- effect of joint compensations (11). The patient’s preoperative lateral radiographs demonstrated a low global lumbar lordotic angle (38.1°), L3/ L4 segmental lumbar lordotic angle (14.1°), and L5/S1 segmental lumbar lordotic angle (13.6°). These angles are consistent with a hypolordotic lumbar spine (2). One of the most common complications of posterior lumbar fusions (TLIF, PLIF) is failure to mitigate the iatrogenic loss of lumbar lordosis post-fusion (10, 11, 13, 14). In the current case, it is likely that the patient’s symptomatic hypolordosis was caused or exacerbated by the TLIF (1, 11). Literature supports that the lordotic loss with posterior fusion is markedly higher (~10°) than anterior fusion (13). Furthermore, studies show that 67% of lumbar lordosis originates from the L4/L5 and L5/S1 disc space anatomy (11). Thus, surgery at these levels has a higher predilection towards postoperative lumbar hypolordosis (11). Thus, the primary surgeon utilized a 15° SPIRA® implant at the L5/S1 disc space and an 8° SPIRA® implant at the L3/L4 disc space to restore the lumbar lordosis. Postoperative lateral radiographs documented a long-term improvement in the global lumbar lordosis angle by 10.2°. As a result, the patient fell within the normal lordotic angle range (40°-70°) (15). Final radiographic measurements revealed an improved global lumbar lordotic angle (49.3°), L3/L4 segmental lumbar lordotic angle (19.4°), and L5/S1 segmental angle (20.3°). These angles and her erect posture indicated a restoration of the lumbar sagittal plane alignment (1, 16, 17).
Asymmetric Pain Secondary to Lumbar Scoliosis
In addition to lumbar hypolordosis, the patient demonstrated symptoms of coronal plane imbalance. She presented having worse right-sided radiating lower extremity pain. In surgery, the left-sided posterior pedicle screws post-TLIF were loose unlike the right-sided pedicle screws. These findings coincided with AP radiographs documenting a mild left-sided scoliosis. With a coronal plane curvature of greater than 10° and a vertebral rotation deformity, the patient had a diagnosis of scoliosis (Cobb angle: 11.6°) (18). Untreated scoliosis causes progressive vertebral remodeling, irregular weight dispersion, muscle spasms, and nerve root compression (19, 20). These symptoms result from the increased energy expenditure needed to counter the concavity and maintain an erect posture (19, 21). The failure to treat even a modest degree of malalignment is manifested through symptoms (19, 21). Treatment for mild cases, such as the present patient, are primarily non- surgical (18). However, since the patient was undergoing a revision, the correction was hastened through surgical means. The primary surgeon chose a combination of anterior-posterior reconstruction to correct the lumbar coronal plane imbalances and reverse the axial rotation. Final postoperative radiographs reveal a 6.8° improvement of the coronal Cobb angle from 11.6° to 4.8°, and the patient’s asymmetric pain resolved in the early postoperative period. Thus, the combined treatment choices were effective in addressing the patient’s multidimensional imbalances.
Persistent Lumbar Pain Secondary to Pseudarthrosis
Though the majority of the pain that the patient experienced was in the lower extremity, she had persistent pain at the previous TLIF surgical site. The CT scan and surgical visualization confirmed minimal bone growth around the L4/L5 PEEK implant. Pain and minimal or no bone growth are the primary features of symptomatic pseudarthrosis
(22). Studies document a higher rate of pseudarthrosis (45%) with an isolated posterior fusion technique, such as PLIF or TLIF, compared to a combined anterior and posterior fusion approach, which is associated with significantly higher fusion rates (>90%) (22, 23, 24). To mitigate the propensity of pseudarthrosis at the adjacent fusion sites, a combine anterior-posterior fusion technique was utilized in the present patient.
Since the L4/L5 implant in the current patient was non-mobile, firmly impacted within the disc space, and imbedded in the L5 vertebral body, removal could have possibly damaged the vertebral body and surrounding structures. Thus, the PEEK implant was left in place. Our findings support the current literature documenting a high rate of symptomatic pseudarthrosis in patients treated with PEEK cages (25, 26, 27). A study by Olivares found that PEEK implants reduced osteoblastic differentiation of osteoprogenitor cells and stimulated proteins associated with inflammation, necrosis, DNA damage, and apoptosis (26). In contrast, production of these bone growth-inhibitory proteins
was lowest on roughened titanium implants (26). Additionally, Eckman et al. reported that PEEK (3.6GPa) was significantly weaker than bone (10-30GPa), but titanium (100GPa) was significantly stronger than bone. Therefore, if cage subsidence is present, the integrity of the PEEK implant may be compromised (28). Based on his research, titanium was best suited to maintain disc height (28).
In the present case, the surgeon chose a roughened porous titanium SPIRA® implant for the remaining L3/L4 and L5/S1 anterior fusion sites due to the inner open cylindrical construct and textured surface. Thus, the implant fostered osteoconduction as bone growth was noted on the final postoperative x-rays. To address the lack of bone growth and failure to maintain disc height at L4/L5, the accessible vertebral endplates were prepared using curettage through both anterior and posterior techniques. Final radiographs confirmed more bone growth one year post-revision compared to five years post-TLIF.
Conclusion
To our knowledge, this is the only report and literature review to have retrospectively assessed the impact of surgical choice and implant choice on patient symptomology. The patient in the current study underwent both an unsuccessful TLIF with a PEEK cage and a successful subsequent AP lumbar fusion with titanium cages. The SPIRA® implants used in the anterior and posterior fixation were successful in maintaining disc height, decompressing the neural foramen, promoting bone growth, and restoring segmental and global lumbar lordosis long-term. These findings were documented by final postoperative radiographs and the patient’s void of clinical symptoms. By analyzing the results of two different surgical approaches with two different implant types in the same patient with the same symptoms, we are able to ascertain the implications of surgical choices on patient outcomes.
REFERENCE:
Priya Sundararajan1, DPM, FACFAS; Stephen B. Wolf2, MD, FAAOS (APRIL 2022). Understanding The Potential Impact Of Procedure And Implant Choice On Postoperative Clinical Symptoms: A Case Report Of Revision Anterior-Posterior Lumbar Fusion After TLIF. https://www.cambermedtech.com/articles-white-papers