Table 4.
Prospective controlled studies
| Study/author, methodology | Main inclusion criteria, main exclusion criteria | Type/level LDH | Interventions/technique/instrumentation | Follow-up: duration and outcome | Comment |
|---|---|---|---|---|---|
| Hermantin et al. [11], randomized n = 60 | Inclusion criteria | Type: intracanal LDH | Index: arthroscopic microdiscectomy | Follow-up I: mean 31 months (range 19–42), 0% lost to follow-up | |
| Radiculopathy | Level: single level, L2–S1 | Pure intradiscal technique Kambin technique biportal: n = 2 | C: mean 32 months (range 21–42), 0% lost to follow-up | ||
| Post-tension sign | n = 30 ♀8 ♂22, mean 39 years, range 15–66 | Pain (VAS) I: pre-op. 6.6, follow-up 1.9, difference 4.7 = 71% | |||
| Neurological deficit | Control: open Laminotomie, n = 30 ♀13 ♂17, mean 40 years, range 18–67 | C: pre-op. 6.8, follow-up 1.2, difference 5.6 = 82% | |||
| Exclusion criteria | Return to work (mean): I: 27, C: 49 days | ||||
| Sequestration | GPE (unclear instrument) I: 97%, C: 93% excellent + good | ||||
| Previous surgery (same level) | PS (very satisfied) I: 73%, C: 67% | ||||
| Central or lateral stenosis | Complications I: 6.7%, C: 0% | ||||
| Re-operations I: 6.7%, C: 3.3% | |||||
| Hoogland et al. [16], not adequately randomized (birth date) n = 280 | Inclusion criteria | Type: all LDH | Index: transforaminal endoscopic discectomy | Follow-up I: 24 months, 16% lost to follow-up | |
| Radiculopathy | Level: single level, L2–S1 | Intradiscal and intracanal technique, Thessys instrumentation, n = 142 ♀50 ♂92, mean 41 years, range 18–60 | C: 24 months, 16% lost to follow-up | ||
| Post-tension sign | Control: transforaminal endoscopic discectomy combined with injection of low-dose (1,000 U) chymopapain. n = 138 ♀44 ♂94, mean 40.3 years, range 18–60 | Pain leg (VAS) I: pre-op. 8.0, follow-up 2.0, difference 6.0 = 75% | |||
| Neurological deficit | C: pre-op. 8.2, follow-up 1.9, difference 6.3 = 77% | ||||
| Exclusion criteria | Pain back (VAS) I: pre-op. 8.2, follow-up 2.6, difference 5.6 = 68% | ||||
| Obesity | C: pre-op. 8.2, follow-up 2.8, difference 5.4 = 66% | ||||
| Previous surgery (same level) | GPE (MacNab) I: 16% excellent, 33.8% good, 0.9% poor | ||||
| C: 63% excellent, 27% good, 0.9% poor NS | |||||
| PS I: 85%, C: 93% S | |||||
| Recurrence I: 7.4%, C: 4.0% | |||||
| Complications I: 2.1%, C: 2.2% NS | |||||
| Re-operations I: 6.1%, C: 1.6% | |||||
| Krappel et al. [31], not adequately randomized (alternating) n = 40 | Inclusion criteria | Type: not specified | Index: endoscopic transforaminal nucleotomy | Follow-up I: range 24–36 months, 5% lost to follow-up | |
| Radiculopathy | Level: single level, L4–S1 | Pure intradiscal technique, Mathews technique, Sofamor–-Danek endoscope, n = 20 ♀? ♂?, mean 41 years, range 36–54 | C: range 24–36 months, 0% lost to follow-up | ||
| Post-tension sign | Control: Open nucleotomy, n = 20 ♀? ♂?, mean 39 years, range 25–43 | GPE (MacNab) I: 16% excellent, 68% good, 0% poor | |||
| Neurological deficit | C: 15% excellent, 60% good, 0% poor NS | ||||
| Exclusion criteria | Return to work I: 100%, C 100% | ||||
| Sequestration | Recurrence I: 5%, C 0% | ||||
| High iliac crest | Complications I: 0%, C 0% | ||||
| Re-operations I: 5%, C 0% | |||||
| Lee et al. [34], not adequately randomized, (preference of surgeon) n = 300 | Inclusion criteria | Type: not specified | Index: percutaneous endoscopic laser discectomy (PELD), n = 100 ♀35 ♂65 | Follow-up 12 months, 0% lost to follow-up | Authors included n = 3 patients in satisfactory group after re-operation. These were labelled as ‘adverse effects’ and ‘re-operations’ in this review |
| Radiculopathy | Level: single level, L3–S1 | Pure intradiscal technique, Kambin technique | GPE (modified MacNab) I: 29%, C1: 20%, C2: 18% excellent | ||
| Exclusion criteria | Control 1: chemonucleolysis, n = 100 ♀24 ♂76 | I: 39%,C1: 35%, C2: 30% good | |||
| Sequestration | Control 2: automated percutaneous discectomy, n = 100 ♀28 ♂72 | I: 9%, C1: 18%, C2: 20% poor | |||
| Return to work (6 weeks) I: 81%, C1: 67%, C2: 66% | |||||
| Complications I: 4%, C1: 10%, C2: 3% | |||||
| Re-operations I: 9%, C1: 18%, C2: 20% | |||||
| Mayer and Brock [39], randomization not specified n = 40 | Inclusion criteria | Type: not specified | Index: percutaneous endoscopic discectomy | Follow-up 24 months, 0% lost to follow-up | |
| Radiculopathy | Level: single level, L2–L5 | Pure intradiscal technique, modified Hjikata instrumentation, n = 20 ♀8 ♂12, mean 40 years, range 12–55 | GPE (S/S-score) I: 70% satisfactory, 0% poor | ||
| Post-tension sign | Control: open microdiscectomy, n = 20 ♀6 ♂14, mean 42 years, range 19–63 | C: 65% satisfactory, 15% poor | |||
| Neurological deficit | Patient satisfaction I: 55%, C: 55% | ||||
| Exclusion criteria | Recurrence I: 5%, C: 0% | ||||
| Sequestration | Complications I: 0%, C: 5% | ||||
| Previous surgery (same level) | Re-operations I: 15%, C: 5% | ||||
| Cauda syndrome | |||||
| Segmental instability | |||||
| Ruetten et al. [47], not adequately randomized (alternating by independent person) n = 200 | Inclusion criteria | Type: all LDH | Index: endoscopic transforaminal and interlaminar lumbar discectomy | Follow-up I: 24 months, 8% lost to follow-up | Authors excluded n = 6 from analyses due to revision surgery. These were taken into account in this review, n = 41 were operated via a transforaminal endoscopic technique, n = 59 patients were operative via an interlaminar endoscopic technique |
| Radiculopathy | Level: single level, L1–S1 | Intracanal technique, YESS, Richard Wolf instrumentation, n = 100 | C: 24 months, 8% lost to follow-up | ||
| Neurological deficit | Control: open microdiscectomy, n = 100, mean 43 years, range 20–68 | Pain leg (VAS) I: pre-op.75, follow-up 8, difference 67 = 89% | |||
| Exclusion criteria | Overall, n = 200 ♀116 ♂84, mean 43 years, range 20−68 | C: pre-op. 71, follow-up 9, difference 62 = 87% | |||
| Not specified | Pain back (VAS) I: pre-op. 19, follow-up 11, difference 8 = 42% | ||||
| C: pre-op. 15, follow-up 18, difference −3 = −8.3% | |||||
| Functional status: (ODI) I: pre-op. 75, follow-up 20, difference 55 = 73% | |||||
| C: pre-op. 73, follow-up 24, difference 49 = 67% | |||||
| Patient satisfaction I: 97%, C: 88% | |||||
| Return to work (mean) I: 25 days | |||||
| C: 49 days S | |||||
| Recurrence I: 6.6% C: 5.7% NS | |||||
| Complications I: 3%, C: 12% S | |||||
| Re-operations I: 6.8% C: 11.5 |
Intervention as quoted in original article. Post-tension signs denotes positive tension signs (straight leg raising test or contralateral straight leg raising test)
Outcomes: S statistically significant, NS not statistically significant, PS patient satisfaction, MacNab MacNab score as described by MacNab [39]. The sum of ‘excellent’ and ‘good’ outcomes are labelled ‘satisfactory’, GPE global perceived effect, S/S-score Suezawa and Schreiber score [40], ODI Oswestry disability index [38]