There is a spectrum of posterior-only releases and osteotomies. The posterior release also known as the wide posterior release was first described by Shufflebarger [9, 10]. He uses this approach with a three-stage approach done in a single day. He first performs a posterior release by removing the ligamentum flavum interspinous ligament and release through the facet joints with partial facetectomy. At the time of the posterior release, he places the pedicle screws in the lumbar spine. He performs an anterior approach and discectomies at multiple levels in the lumbar spine. The disc spaces are then prepared for fusion with disc height elevation with harms cages. The posterior procedure then involves placing the final rods and compression to achieve lordosis and correction of the lumbar scoliosis. The multiple stages of posterior and anterior and then posterior approach are not used very often. Most deformities are done posterior-only or anterior or lateral approach followed by posterior approach.

The posterior approach involves removing the interspinous ligament, part of the spinous process and lamina, the ligamentum flavum, and the entire facet joint. This was originally described in a fused spine where the osteotomy was performed through the facet joint that was already fused (Smith-Petersen osteotomy) (see Fig. 15.2a, b). In the mobile spine with supple disc spaces, the release is called a Ponte osteotomy. The osteotomy allows for aggressive posterior release, direct decompression of the neural elements, and shortening of the posterior column. Most surgeons are able to achieve 5–10° of lordosis through each level of osteotomy. This osteotomy can be very useful in correction of the lumbar curve as well as obtaining lumbar lordosis. If the disc space is rigid or fused, a posterior-only facetectomy is not as effective and may need to be combined with additional approaches and releases.

Various posterior lumbar interbody fusion techniques have been utilized. Posterior lumbar interbody fusion (PLIF) was the first to mobilize lumbar segments at multiple levels. After mobilization of the discs, posterior lumbar interbody spacers are placed to achieve lordosis as well as provide stability. This can be accomplished utilizing a bilateral approach. More recently, transforaminal lumbar interbody fusions (TLIF) have been utilized more often. The transforaminal lumbar interbody cage is inserted from one side only compared to the posterior lumbar interbody fusion cages that are inserted bilaterally. Transforaminal interbody fusion cage is shaped like a crescent and placed as anterior as possible to create lordosis. The PLIF approach involves more retraction of the nerve roots and can cause nerve root damage. It is however very useful in mobilizing the disc space bilaterally. Difficulty with the transforaminal lumbar interbody fusion technique is the amount of distraction that can be obtained within the disc space without cutting the annulus. If the annulus is mobile, the TLIF approach is very successful. On the other hand, if the annulus is stiff and fibrotic, it is difficult to obtain release of the disc space and adequate distraction to gain lordosis. In addition, the end plate preparation and placement of the graft have to be meticulously done to avoid end plate violation and subsequent graft subsidence. A study reported by Cho et al. found that 42 % of the patients developed sagittal decompensation after TLIF combined with a posterior fusion [11]. The preoperative sagittal imbalance as well as a high pelvic incidence proved to be the most significant risk factors in developing sagittal decompensation postoperatively. This study also found additional complications at the more distal segments including pseudarthrosis and implant failure at the lumbosacral junction. The radiographs shown in the paper found that the S1 screws were not protected with iliac fixation [11]. Other authors have also shown that sagittal plane realignment is very important but harder to obtain with TLIF [12].

Lateral minimally invasive approaches have been developed by multiple surgeons. There are two basic approaches. The first approach obtains disc access by dilating through the substance of the psoas muscle. There is a specific retractor that docks onto the disc space and then is used to dilate the muscle in a controlled fashion. Neural monitoring is used to place and dilate this retractor to avoid damaging the lumbar plexus [13–15]. The next approach achieves disc access by docking anterior to the psoas muscle [16]. This minimally invasive approach attempts to minimize the risk of injury to the lumbar plexus. The lateral minimally invasive approaches have had some adverse events. The grafts that are used can subside into the vertebral body if the end plate is not carefully prepared or the graft violates the end plate as it is inserted. The lumbar plexus is at risk as it is in the substance of the psoas muscle. There have been reports of pain from compression of the lumbar plexus and weakness in the proximal thigh. The recommendation is to minimize the distraction of the self-retaining retractor and minimize that time the retractor is pushing onto the lumbar plexus through the psoas muscle. Neural monitoring is mandatory for this technique especially when dilating through the psoas muscle in order to prevent nerve damage.