Full Endoscopic Assisted Pars Repair

The pars interarticularis is a small strut of bone that connects the upper and lower joints of a vertebra, part of the bony ring at the back of the spine. In young people, particularly those who do a lot of repeated bending and extension — gymnasts, cricketers, fast bowlers, footballers — this strut can develop a stress fracture, a defect called spondylolysis. It most often affects the lowest lumbar vertebra and can cause persistent back pain that is worse with activity and extension. If the fracture does not heal and the vertebra begins to slip forward, it can progress to a spondylolisthesis. In many people the defect settles with rest and rehabilitation; when it does not, surgery is considered.

Here is the key decision, and it matters most in young patients. The traditional operation for a symptomatic pars defect that will not heal is to fuse the segment — but fusing a level in a teenager or a young adult permanently removes that segment's movement and places extra load on the neighbours over a lifetime. A direct pars repair takes a different path: rather than fusing the segment, it mends the fracture itself — cleaning out the non-healing defect, adding bone graft, and holding it with a small screw or a screw-and-hook construct across the break — so the bone can knit and the segment keeps moving. For a young, active person, preserving that motion is a significant advantage, and it is why direct repair, where suitable, is such an attractive option.

Bringing endoscopic assistance to this operation applies the low-demand, low-insult principle I hold throughout my practice. Endoscopic visualisation allows the pars defect to be cleared of the fibrous non-union tissue precisely, under magnified vision, and any accompanying nerve compression to be addressed, through much smaller exposures than an open repair requires — sparing the muscles that a young, athletic spine depends on. The defect is prepared, grafted and stabilised, with the aim of achieving solid healing of the pars while disturbing as little as possible of the surrounding tissue, so recovery and return to sport are supported. Careful selection is essential — direct repair works best in younger patients, with a defect at a single level, minimal or no slip, and a healthy disc below.

I am candid that this is a carefully selected operation rather than a routine one. The judgement of who is a good candidate — the age, the level, the state of the disc, the presence or absence of a slip — is as important as the technical execution, and getting that selection right is what gives direct repair its good results. The technique itself, mending a small bony bridge accurately and grafting it to heal while protecting the nearby nerves, rewards precision and experience. Bringing endoscopic assistance to it is exactly the sort of motion-preserving, tissue-sparing refinement that my focus on endoscopic surgery is about — but always applied to the right patient.

The evidence supports direct pars repair as a motion-preserving alternative to fusion in well-selected young patients, with good union and return-to-sport rates reported across techniques, and a meta-analysis of direct repair methods documenting solid fusion in the great majority. Minimally invasive and endoscopic-assisted approaches to direct repair have been described in technical notes and case series — including endoscopic clearance of the defect and repair in young adults — reporting good healing with the tissue-sparing benefits of a smaller exposure. Reviews of direct repair in athletes report high rates of return to sport. The consistent message is that direct repair, in the right young patient, preserves motion and gets people back to activity, and that minimally invasive routes deliver this with less disruption.

Because the segment is repaired rather than fused, its movement is preserved, which matters greatly for a young, active person. Recovery centres on allowing the pars to heal — a period of protected activity over some months while the bone knits, guided by physiotherapy, followed by a graded return to sport once healing is confirmed. The tissue-sparing endoscopic-assisted approach supports a more comfortable early recovery. Healing is followed up carefully over the longer term, because achieving solid union of the pars is what makes the repair last.

• —Sairyo K, et al. Minimally invasive direct repair of pars defects in young adults using a spinal endoscope: technical note. (PMID 17882757)
• —Percutaneous endoscopic-assisted direct repair of pars defect without general anaesthesia: technique and case series. (PMC7268338)
• —Direct surgical repair of spondylolysis in athletes: indications, techniques and outcomes. (PMID 22044108)
• —Comparison of techniques of direct pars interarticularis repair for spondylolysis and low-grade spondylolisthesis: meta-analysis. (PMID 29290131)
• —Minimally invasive direct repair of bilateral lumbar pars defects in athletes. (PMID 23737800 / PMC3657441)
• —Direct repair of pars defects using intraoperative O-arm navigation and microendoscopic techniques. (PMID 27488290)
• —Endoscopic-assisted fusion for lumbar pars fracture repair in an adolescent. (PMID 37536252)