Pedicle screw fixation and posterior fusion for lumbar degenerative diseases: effects on individual paraspinal muscles and lower back pain; a single-center, prospective study

Abstract

BackgroundTo the best of our knowledge, there have been no reports on the points at which the denervated multifidus and erector spinae muscles become reinnervated after pedicle screw fixation and posterior fusion in patients with lumbar degenerative diseases. Our study was designed to confirm reinnervation of denervated paraspinal muscles following pedicle screw fixation and posterior fusion and to confirm alleviation of the patients’ lower back pain (LBP).MethodsIn this prospective study, we enrolled 67 patients who had undergone pedicle screw fixation and posterior fusion. The surgery had alleviated their leg pain, but the patients complained of LBP at the L3-5 level 3 months after the surgery. The patients were divided into two groups (I and II) according to the level at which pain was experienced. Paraspinal mapping scores were recorded preoperatively and 3, 6, 12, and 18 months postoperatively. Oswestry Disability Index and visual analogue scale scores were determined. Regression analyses using a general linear model and a mixed model were performed.ResultsPedicle screw fixation and posterior fusion significantly denervated the multifidus and erector spinae not only in the surgical segment, but also in adjacent segments. Group I patients displayed reinnervation in the denervated erector spinae and multifidus muscles at 12 and 18 months, respectively. In contrast, group II showed reinnervation only in of the denervated erector spinae of the upper segment at 18 months, with no other areas of reinnervation. Postoperative LBP was significantly diminished at 12 months in group I and at 18 months in group II. There was also significantly less LBP at 6 months (prior to reinnervation of the paraspinal muscles).ConclusionsThe denervated multifidus and erector spinae muscles at L4–5, which had been denervated using pedicle screw fixation and posterior fusion, were significantly reinnervated at 18 months postoperatively, whereas patients with denervation at L3–5 had only a tendency to be reinnervated at follow-up. Postoperative LBP in these patients was significantly diminished at the follow-up visits.

Reattachment of the Multifidus Tendon in Lumbar Surgery to Decrease Postoperative Back Pain: A Technical Note

“…The posterior approach to the lumbar spine, most commonly used for decompression and fusion procedures, involves significant manipulation of the paraspinal muscles, particularly the LM [1][2][3][4][5][6]. Upon standard superficial exposure, the tendon origin of the LM is dissected from the spinous process and, together with other paraspinal muscles, is retracted laterally to obtain an adequate surgical window [6,14]. Such manipulation places the LM at a significant risk of iatrogenic damage resulting from crush injury, devascularization, and denervation, all of which have been associated with postoperative pain and muscle atrophy [1][2][3][4].…”

“…Numerous reports have shown that patients with postoperative LBP exhibit gross and histological signs of LM degeneration, such as muscle atrophy (decreased crosssectional area [CSA]), LM intramuscular adipose tissue accumulation, and LM denervation [1,2,4,6,[8][9][10][13][14][15]. These findings have been attributed, in part, to the imprecise nature of the LM dissection as well as the intraoperative use of self-retaining retractors, both of which have been shown to result in ischemic necrosis, scar tissue formation, denervation, and atrophy [5,8,10,14]. Given these findings and the inevitability of intraoperative paraspinal muscle manipulation, the following technical report describes methods by which surgeons may minimize tissue disruption and respect the anatomical position of the LM to ultimately expedite recovery, minimize postoperative pain, and improve patient satisfaction.…”

Ti-24Nb-4Zr-8Sn Alloy Pedicle Screw Improves Internal Vertebral Fixation by Reducing Stress-Shielding Effects in a Porcine Model

“…Stress conduction can be caused by lumbar degeneration [ 16 ], whereas back pain and other symptoms can be reduced or even disappear if lumbar dynamic internal fixation system precisely limits the activities of the vertebral body [ 30 ]. Theoretically, lumbar dynamic stability system reduces adjacent segment degeneration and the stress on the intervertebral bone graft and promotes bone healing and spine recovery.…”