Recurrent Tethering: A Common Long-Term Problem after Lipomyelomeningocele Repair

Abstract

The authors reviewed the records of 94 patients who underwent initial repair of a lipomyelomeningocele between 1982 and July 1996 at the Children’s Hospital of Pittsburgh to determine the incidence and time course of symptomatic retethering. In each of these patients, the initial operative goals were to microsurgically debulk as much of the lipoma as possible to allow the conus to move freely within the spinal canal, to divide any tethering arachnoidal adhesions, to close the pia if possible and to reconstitute a capacious thecal sac, using a dural graft if necessary. With a median follow-up of 58 months, 19 of these patients (20.2%) required 28 subsequent operations for symptomatic retethering. Median time between the initial procedure and reoperation for retethering was 52 months. The primary complaint of 12 patients was intractable low-back or leg pain. Other common symptoms were progressive bowel and/or bladder dysfunction, deterioration of motor function and foot deformities. The decision to reoperate was based predominantly on the clinical situation of the patient; magnetic resonance imaging was used to confirm the location and extent of tethering. Patients with transitional lipomas had a significantly higher frequency of symptomatic retethering than those with caudal or dorsal lesions (p < 0.05). No other clinical or technical feature correlated with an increased frequency of retethering. In particular, none of a variety of types of dural graft materials appeared to entirely prevent symptomatic retethering. Following reoperation, pain complaints resolved and many of the other symptoms improved partially or resolved completely. Although the long-term results were also favorable in the majority of patients, a small subgroup (n = 6) exhibited repetitive symptomatic tethering that proved increasingly difficult to treat. We concluded that symptomatic retethering is a common problem in children with lipomyelomeningoceles, even after an adequate initial operation. To date, no type of graft material has been shown to entirely prevent this problem. Close long-term surveillance of such patients is required to allow detection and treatment of symptomatic retethering.

Letter to the Editor: Asymptomatic lipomas of the conus medullaris

“…As they correctly emphasized, worse results have been reported by the Parisian authors 5,12,15,16 and also by others, 1 but the incidence of spinal cord retethering following lipoma resection has been repeatedly found to be between 10% and 20%. 2,3,4,13 Apart from the cited papers by Pang et al, 10,11 there are also papers by other authors reporting results quite comparable with ours. For instance, Wu et al 14 demonstrated that 84% of their 43 patients maintained stable urodynamic and neurological functions after surgery.…”

Cord untethering for lipomyelomeningocele: expectation after surgery

“…7,13,15,19 The pattern of postoperative deterioration compared with preoperative symptoms from the British Columbia Children's Hospital series is shown in Table 2. Of those patients presenting with normal neurological function, without orthopedic or sphincteric dysfunction, 59% continued to experience clinically normal function throughout the last follow-up.…”

“…Figure 1 provides an approximation of the time to deterioration for nonsurgically treated LMMCs; the curves indicate the deterioration following surgical untethering. 7,15,19 The British Columbia's Children's Hospital, Paris, and Pittsburgh series included all patients and the Chicago series included only those with symptoms prior to untethering. The findings in the more recently published NEM series were not substantially different from reports published earlier.…”

“…Postuntethering symptomatic deterioration unrelated to the operative intervention has been reported in most surgical series, although the frequency and time to deterioration vary. 3,7,18,20 The time to development of specific symptoms differs depending on the symptom being assessed and the duration of follow-up. 6,8 Neurological and orthopedic deterioration is detected sooner than deterioration in urinary control.…”

“…In the few long-term follow-up studies of surgically treated patients with transitional LMMCs, investigators have demonstrated a significant risk of symptom progression and deterioration despite surgically adequate untethering. 1,[6][7][8]15,[18][19][20] The purpose of this paper was to review the evidence regarding the timing and pattern of deterioration prior to and following initial cord untethering in patients with transitional LMMCs, to describe the differences in the presentation of transitional lesions based on the morpholNeurosurg. Focus /…”