Park Daniel K, Weng Chong, Zakko Philip, Choi Dae-Jung
Beaumont Hospital, Royal Oak, Michigan.
Himnaera Hospital, Dong-Gu, Busan, South Korea.
JBJS Essent Surg Tech. 2023 Jun 27;13(2). doi: 10.2106/JBJS.ST.22.00020. eCollection 2023 Apr-Jun.
Unilateral biportal endoscopy (UBE) is a novel minimally invasive technique for the treatment of lumbar spinal stenosis and lumbar disc herniations. Uniportal endoscopy was utilized prior to the advent of UBE and has been considered the workhorse of endoscopic spine surgery (ESS) for lumbar discectomy and decompressive laminectomy. However, there are theoretical advantages to UBE compared with traditional uniportal endoscopy, including that the procedure utilizes typical spinal equipment that should be readily available, requires less capital cost and optical instrumentation, and provides greater operative flexibility as a result of utilizing both a working and a viewing portal.
A 0-degree arthroscope is typically utilized for discectomy and lumbar laminectomies. The use of a radiofrequency ablator is critical to help coagulate osseous and muscle bleeders. For irrigation, gravity or a low-pressure pump, typically <40 mm Hg, can be utilized. Further details regarding irrigation pressure are provided in "Important Tips." The use of a standard powered burr is typical to help osseous decompression, and Kerrison ronguers, pituitaries, osteotomes, and probes utilized in open or tubular cases suffice. Two incisions are made approximately 1 cm lateral to the midline. If working from the left side for a right-handed surgeon, the working portal is typically made at the lower laminar margin of the target level. The camera portal is then made typically 2 to 3 cm cephalad. A lateral radiograph is then utilized to confirm the portal placements. From the right side, the working portal is cephalad and the camera portal is caudal. Because of the switch, the portals may be shifted more distally.The first step is creating a working space because there is no true joint space in the spine. With use of radiofrequency ablation, a working space is created in the interlaminar space. Next, with use of a powered burr or a chiseled osteotomy, the base of the cephalad spinous process is thinned until the insertion of the ligamentum flavum is found. Next, the ipsilateral and contralateral laminae are thinned in a similar fashion. Once the osseous elements are removed, the ligamentum flavum is removed en bloc. The traversing nerve roots are checked under direct high-magnification visualization to ensure that they are decompressed. If a discectomy is necessary, standard nerve-root retractors can be utilized to retract the neural elements. With use of a blunt-tip elevator, the anular defect can be incised and the herniated disc can be removed under direct high-power visualization. In addition, a small curet can be utilized to create a defect in the weakened anulus or membrane covering the extruded disc material in order to help deliver the herniated disc material. Epidural veins are coagulated typically with use of a fine-point bipolar radiofrequency device.
Nonoperative treatments include oral anti-inflammatory drugs, physical therapy, and epidural injections; if these fail, alternative surgical treatments include open lumbar laminectomy and/or discectomy, tubular lumbar laminectomy and/or discectomy, and other minimally invasive techniques, such as microendoscopy, uniportal endoscopy, and microscopy-assisted decompression.
UBE is a minimally invasive surgical procedure that better preserves osseous and muscular structure compared with open and tubular techniques. Conventional lumbar laminectomy involves dissection and retraction of the multifidus muscle from the spinous process to the facet joint. This exposure can damage the delicate posterior dorsal rami. Long retraction time can also lead to pressure-induced muscle atrophy and potentially increased chronic low back pain. Alternatively, smaller incisions and shorter hospital stays are possible with UBE.Similar to UBE, tubular surgery can minimize soft-tissue damage compared with open techniques; however, in a randomized trial assessing techniques for spinal stenosis surgery, Kang et al. found that UBE and tubular surgery had similarly favorable clinical outcomes at 6 months postoperatively but UBE resulted in decreased operative time, drain output, opiate use, and length of hospital stay.Furthermore, the use of an endoscope in the biportal technique allows ultra-high magnification of the spinal pathology, decreased capital costs, and the ability to use 2 hands with freedom of movement. UBE provides clear visualization of the neural elements while keeping maximal ergonomic efficiency with the surgeon's head looking straight forward, the shoulders relaxed, and the elbows bent to 90°. Continuous irrigation through the endoscope also helps with bleeding and decreasing the risk of infection.
Long-term outcomes do not differ substantially between discectomies performed with use of the presently described technique and procedures done with more traditional minimally invasive (i.e., tubular) techniques; however, visual analogue scale scores for back pain may be better in the short term, and there is evidence of a shorter hospital stay with UBE. Complication rates did not differ from other minimally invasive techniques. When comparing UBE and stenosis, Aygun and Abdulshafi found that UBE was associated with decreased hospital stays, operative time, and blood loss and better clinical outcomes up to 2 years postoperatively compared with tubular laminectomy.
The optimal hydrostatic pressure is 30 to 50 mm Hg. Pressure is determined by the distance between the fluid source and the working space. Because the working space does not change, the height of the bag decides pressure. A simple formula for pressure is calculated by dividing the distance from the working field to the irrigation source by 1.36. A rule of thumb is that if the bag is 50 to 70 cm above the patient's back, the pressure should be adequate. The advantages of using gravity rather than a pressure pump are that excessive fluid solution pressure in the epidural space can cause neurological issues such as nuchal pain, headache, and seizure. Additionally, if the intertransverse membrane or the lateral margins of the disc are violated, hydroperitoneum can occur unknowingly due to the high-pressure system.Gravity or pump pressure of >40 mm Hg may elevate epidural pressure and mask operative bleeding. When the pump is turned off at the end of the surgical procedure, a postoperative epidural hematoma may occur because the bleeding source may not have been recognized while the pump pressure was on.Excessive pump pressure may lead to an increase in intracranial pressure, causing headache or delayed recovery from general anesthesia with stiff posture and hyperventilation.Make sure fluid is emerging from the working portal and the muscle area is not swelling to prevent soft-tissue fluid extravasation.Epidural veins are coagulated typically with a fine-point bipolar radiofrequency device.Osseous bleeding can be controlled with bone wax or a high-speed burr.
MRI = magnetic resonance imagingRF = radiofrequencyAP = anteroposterior.
单侧双通道内镜技术（UBE）是一种用于治疗腰椎管狭窄症和腰椎间盘突出症的新型微创技术。在UBE出现之前，单通道内镜已被使用，并且一直被认为是用于腰椎间盘切除术和减压性椎板切除术的脊柱内镜手术（ESS）的主力技术。然而，与传统单通道内镜相比，UBE具有理论上的优势，包括该手术使用的是常见的脊柱设备，这些设备应易于获取，所需的资金成本和光学仪器较少，并且由于同时使用工作通道和观察通道而具有更大的操作灵活性。
通常使用0度关节镜进行椎间盘切除术和腰椎椎板切除术。使用射频消融器对于帮助凝固骨质和肌肉出血点至关重要。对于冲洗，可以使用重力或低压泵，通常压力<40 mmHg。有关冲洗压力的更多详细信息在“重要提示”中提供。通常使用标准动力磨钻来帮助进行骨质减压，并且在开放或管状手术中使用的Kerrison咬骨钳、垂体咬骨钳、骨凿和探针就足够了。在中线旁约1 cm处做两个切口。对于右利手的外科医生，如果从左侧操作，工作通道通常在目标节段的下位椎板边缘处制作。然后通常在头侧2至3 cm处制作观察通道。然后使用侧位X线片确认通道位置。从右侧操作时，工作通道在头侧，观察通道在尾侧。由于操作侧的改变，通道可能会向更远处移位。第一步是创建工作空间，因为脊柱中没有真正的关节间隙。使用射频消融在椎板间隙中创建一个工作空间。接下来，使用动力磨钻或凿骨术，将上位棘突的基部变薄，直到找到黄韧带的附着处。接下来，以类似的方式将同侧和对侧椎板变薄。一旦去除骨质结构，将黄韧带整块切除。在直接高倍视野下检查横过的神经根，以确保它们得到减压。如果需要进行椎间盘切除术，可以使用标准的神经根牵开器来牵开神经结构。使用钝头剥离子，可以切开纤维环缺损，并在直接高倍视野下切除突出的椎间盘。此外，可以使用小刮匙在覆盖突出椎间盘物质的薄弱纤维环或膜上制造一个缺损，以帮助取出突出的椎间盘物质。硬膜外静脉通常使用细尖双极射频设备进行凝固。
非手术治疗包括口服抗炎药、物理治疗和硬膜外注射；如果这些治疗无效，替代手术治疗包括开放腰椎椎板切除术和/或椎间盘切除术、管状腰椎椎板切除术和/或椎间盘切除术，以及其他微创技术，如显微内镜、单通道内镜和显微镜辅助减压。
UBE是一种微创手术，与开放和管状技术相比，能更好地保留骨质和肌肉结构。传统的腰椎椎板切除术包括从棘突到小关节突对多裂肌进行解剖和牵开。这种暴露可能会损伤脆弱的后支背侧支。长时间的牵开也可能导致压力性肌肉萎缩，并可能增加慢性下腰痛。相比之下，UBE可以采用更小的切口和更短的住院时间。与UBE类似，管状手术与开放技术相比可以最大限度地减少软组织损伤；然而，在一项评估脊柱狭窄手术技术的随机试验中，Kang等人发现，UBE和管状手术在术后6个月时具有相似的良好临床结果，但UBE导致手术时间、引流液量、阿片类药物使用和住院时间减少。此外，在双通道技术中使用内镜可以对脊柱病变进行超高倍放大，降低资金成本，并能够双手自由活动。UBE在外科医生头部向前直视、肩部放松且肘部弯曲至90°的情况下，能清晰显示神经结构，同时保持最大的人体工程学效率。通过内镜持续冲洗也有助于止血并降低感染风险。
使用本文所述技术进行的椎间盘切除术与采用更传统的微创（即管状）技术进行的手术相比，长期结果没有显著差异；然而，短期内背痛的视觉模拟评分可能更好，并且有证据表明UBE的住院时间更短。并发症发生率与其他微创技术没有差异。在比较UBE和狭窄手术时，Aygun和Abdulshafi发现，与管状椎板切除术相比，UBE在术后2年内与住院时间缩短、手术时间缩短和失血量减少以及更好的临床结果相关。
最佳静水压力为30至50 mmHg。压力由液体源与工作空间之间的距离决定。由于工作空间不变，袋子的高度决定压力。压力的一个简单计算公式是将从工作区域到冲洗源的距离除以1.36。一个经验法则是，如果袋子高于患者背部50至70 cm，压力应该足够。使用重力而非压力泵的优点是硬膜外间隙中过高的液体压力可能会导致神经问题，如颈部疼痛、头痛和癫痫发作。此外，如果横突间膜或椎间盘的侧缘被侵犯，由于高压系统，可能会在不知不觉中发生腹膜后积液。重力或泵压力>40 mmHg可能会升高硬膜外压力并掩盖手术出血。当手术结束时关闭泵时，可能会发生术后硬膜外血肿，因为在泵压力作用下出血源可能未被识别。过高的泵压力可能会导致颅内压升高，引起头痛或全麻后恢复延迟，伴有僵硬姿势和过度通气。确保液体从工作通道流出，并且肌肉区域没有肿胀，以防止软组织液体外渗。硬膜外静脉通常使用细尖双极射频设备进行凝固。骨质出血可以用骨蜡或高速磨钻控制。
MRI = 磁共振成像；RF = 射频；AP = 前后位
